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Main conference link:http://science.sut.ac.th/spc2022/
Registration / Exhibition and poster presentation set up
Welcome speech by Rector of Suranaree University of Technology
Reported by Dean of Institute of Science, Suranaree University of Technology
Opening speech by President of Thai Physics Society
Opening remark by President of AAPPS
Plenary talk
$\hspace{1cm}$Organometal halide perovskites have captured wide interest as a promising material for light-weight and high-efficiency solar cells. Through recent studies of the organometal halide perovskite solar cells (PSCs), the composition of organometal halide perovskites is recognised as one of the key factors in the improvement of the PCE. In this study, we investigated mixed cation perovskite absorber. The results revealed that incorporating a small amount of K$^+$ into the double organic cation perovskite absorber (FA$_{0.85}$MA$_{0.15}$Pb(I$_{0.85}$Br$_{0.15}$)$_{3}$) improved the photovoltaic performance of PSCs significantly, and K$^+$ incorporation diminished I-V hysteresis. Consequently, the 0.187 cm$^2$ PSC of 22% power conversion efficiency (PCE) without I-V hysteresis were constructed. The crystal lattice of the organometal halide perovskite was expanded with increasing of the K$^+$ ratio, where both absorption and photoluminescence spectra shifted to the longer wavelength, suggesting that the optical band gap decreased. It is concluded that stagnation-less carrier transportation could minimise the I-V hysteresis of PSCs. Additionally, we successfully constructed 2.76 cm$^2$ monolithic PSC mini-module of 20.5% PCE without I-V hysteresis. In the case of MA-free PSCs, the 24.9% PCE (0.187 cm$^2$) and 21.6% PCE (2.76 cm$^2$ monolithic PSC mini-module) were obtained, respectively.
$\hspace{1cm}$On the other hand, the micro-structural aspects within the organometal halide perovskite are still unknown, even though it belongs to a crystal system. In this study, direct observation of the microstructure of the thin film organometal halide perovskite using transmission electron microscopy was investigated. Unlike previous reports, it is identified that the tetragonal and cubic phases coexist at room temperature, and it is confirmed that superlattices composed of a mixture of tetragonal and cubic phases are selforganized without a compositional change. The organometal halide perovskite self-adjusts the configuration of phases and automatically organizes a buffer layer at boundaries by introducing a superlattice. These results shows the fundamental crystallographic information for the organometal halide perovskite and demonstrates new possibilities toward high performance perovskite solar cells.
$\textbf{Keywords}$: organometal halide perovskite, perovskite solar cell, tetragonal, cubic, superlattice
Preparation and coffee break
General oral presentation
Chemo-sensory system is an essential part of the living organism ranging from the smallest bacterial cells up to the most complex neural systems as presented in human. In fact, the sense of smell especially in mammalian species (i.e., dogs and human) occurs at the nanoscale. By transduction of the chemical interactions between the odor molecules with the receptor proteins into electrical signals, smell perception including recognition and memory would be possible. At present, nanoscience of smell attracts a great interest from both academic and industry, particularly in terms of artificial olfaction. Technological applications of artificial noses (aka electronic nose) are vast: for examples, quality assurance of foods, beverage and agricultural products, health-care diagnostics, environmental monitoring, security systems etc. In this lecture, the development of electronic nose from the discovery of sensing materials to the fabrication of chemical sensor array up to the integration into various forms of electronic nose systems, such as portable, handheld and wearable devices, will be presented. We have explored numerous sensor materials based on different sensing mechanism, i.e., metal oxides, porphyrins/phthalocyanines, carbon nanotubes and conductive polymers, in order to span the applications in broad areas. In addition, techniques of hybridization between the sensor materials as well as transduction principles have been examined, leading to enhanced functionality and flexibility of the new electronic nose systems. Especially in this lecture, real-world applications of our electronic noses to assess the quality of foods, diagnose cancer, determine the health status of individuals and monitor the environmental conditions will be demonstrated. Development of a startup business based on this research will be provided in this lecture.
$\textbf{Keywords}$: chemical sensor, electronic nose, smell, artificial sense
Formaldehyde detection is an important method to protect harmful effect on human health. This study aimed to develop a colorimetric sensor for detecting formaldehyde based on thiol-functionalized polydiacetylene (PDA) and zinc oxide (ZnO) nanocomposites. PDA/PDA-SH/ZnO liposomes exhibit a color change from blue to red in the presence of formaldehyde in the range of 100 to 1000 ppm. This color change was easily visualized by the naked-eye and optical absorption spectroscopy. With increasing concentration of formaldehyde, the absorption intensity at 640 nm dramatically decreased, and new absorption peak appeared at 540 nm. The colorimetric response value increase when the concentration of formaldehyde was increased. In addition, the quantitative color change of PDA/PDA-SH/ZnO sensor can be extracted using color RGB images captured by a smartphone. These results suggest a possibility to develop PDA/PDA-SH/ZnO sensor for detecting formaldehyde in real applications.
Keywords: Polydiacetylene, Conjugated Polymer, Nanocomposites, Formaldehyde Detection, Colorimetric Sensors, Digital Image
Urbanization in the Philippines is at a fast pace. As it grows, urban land expansion increases. It results in the conversion of the different land areas in the country. To determine its changes, this study used geographic information system images by using data products of MODIS Terra and Aqua from NASA EOSDIS, it provides satellite images of the Philippines’ cover and land use. Eighteen (18) satellite images were gathered and used in this study. The findings showed that the National Capital Region and Cebu islands regions are the most urbanized areas in the country.
Analysis revealed that both urbanization and vegetation landcover increases while the cropland landcover gradually declines. Multiple linear regression analysis revealed that these variables are significant to each other. It also revealed a positive relationship between urbanization and vegetation, while both showed a negative relationship towards cropland landcover. For the next five (5) years, the Philippines' data revealed that urbanization will increase immensely and expand to 3,181.4523 km² in 2023 from the current 2,952.63 km². Thus, the continuous expansion of two variables revealed that there will be a loss in cropland landcover and will only be 40,215.3680 km² in 2023 from the current 63,139 km² total area, which will be very crucial for agriculture and food security in the country.
As a result of the coronavirus (Covid-19) epidemic, the public has become actively involved in bodily sanitation. The ‘New Normal’ lifestyle now focuses on cleanliness and disinfection to prevent the spread of germs. This research designed and programmed a microcontroller for a UVC disinfection system using an Arduino board as an open-source electronics platform operated with a motion sensor (PIR) and a time control module (RTC). The optical properties of an 8 Watt (W) UVC source were measured. The four UVC sources investigated had wavelengths ranging from 251 to 577 nm. A UVC wavelength of 251 nm eradicates germs but also destroys tissues and is harmful to humans. Experimental results showed that UVC intensity decreased with distance from the source according to the exponential decay function. A control system, installed inside a building to kill germs when there are no humans or pets, can control UVC light source operation with a maximum power of 2 kW. Operational time can be adjusted by settings on the control box, while as an additional level of safety, the system can be turned off if a motion sensor detects movement. Movement detection distance at an angle of -90 to +90 degrees was recorded. Results gave 11 m detection distance at an angle of 0 degrees, with more than 3 m detection distance at -60 to +60 degrees, as suitable for installation above a door. This timer and motion sensor-operated UV germicidal ray system can be safely deployed to keep rooms germ free.
General oral presentation
This work discusses a design framework based on “idea-power” established by the late MIT professor Seymour Papert. The GoGo Board is used as a case study of an educational robotics toolkit that follows this design principle by focusing on making important ideas in STEM learnable more than specific technical skills such as circuit assembly and low-level programming. A collection of fieldwork examples is shown based on the GoGo Board’s 20-year history and case-studies from schools in Thailand, Brazil, USA.
This paper presents an alternative approach to enhance students’ understanding of a simple harmonic motion (SHM) in that baby mobiles were used as a hands-on activity through a game-based STEM lesson. The subject comprised 28 eleventh grade (mattayom five) students of a public high school in Chanthaburi province, Thailand. The activity was conducted in two consecutive parts. The first part started with a brief review of SHM followed by a simple pendulum experiment so that students learned how length of the string, mass of the bob and other quantities affect the period of an oscillating motion. For the second part, a baby mobile competition was assigned to groups of four students for which necessary materials were provided. Students in each group needed to brainstorm, plan, and create their own baby mobile that meets the competition criteria. The winner of the game would share the successful strategy and receive a tiny reward for positive reinforcement. Results, after the completion of this activity, shows a remarkable improvement of students’ understanding after post-activity test (mean = 8.57 out of 10.00, S.D. = 1.61) when compared to pretest (mean = 2.93 out of 10.00, S.D. = 1.52). In addition, the satisfaction survey reveals that students felt more enjoyable and were engaged in the activity with an average score of 4.05 out of 5.00. These findings suggest that integrating a hands-on STEM activity with specific course contents may be one of the potential approaches that promotes students’ engagement and conceptual understanding in physics.
We investigated the results of pre-instruction mathematics test and introductory physics exams of two groups of first-year engineering students at Suranaree University of Technology. We intend to examine the test results to identify factors that predict exam results in the first-year physics course. The first and the second groups took their physics classes in the first and second trimester of the academic year 2020 respectively. Here, we report our analysis of the pre-instruction math tests and claim that they meet reasonable standards for reliability and validity. As a by-product of this investigation, we found that there was no gender gap in the math test results.
“How to teach effectively” has become challenging to many teachers after their classrooms were moved to an online platform. For high-school physics, we found that students struggled to grasp the concept when learning in the online classroom. Circular motion is the topic that is difficult to focus on details. They could not understand the content well while concentrating on the screen. Some of them lost the attention during the class. The aim of this work is to investigate the achievement of using collaborative learning to teach the first three steps of circular motion problem solving. The three steps are (i) identifying the path of motion and its radius, (ii) drawing a free-body diagram, and (iii) finding the components of forces acting on the object. The method was applied to an online physics classroom with 12 high-school students of science and mathematics program. Finding of the research was interpreted by pre- and post-tests, and video recording during the teaching. The result showed that there were more students who could interpret the circular motion situation correctly than the beginning of the class. Their understanding has been improved. They could interpret the path of motion and the forces acting on the object and some of them could find the centripetal force correctly. Moreover, there was an interaction between the students that related to their understanding of the topic. Details on how collaborative learning was conducted for an online teaching will be given, along with the limitation and future improvement.
Keywords: High school physics, Circular motion, Collaborative learning, and Centripetal force
Alkali titanates including the Andesson-Wadsley type A$_\text{2}$O·nTiO$_\text{2}$ (A = alkali) and the lepidocrocite-type A$_\text{x}$M$_\text{y}$Ti$_\text{2-y}$O$_\text{4}$ are diverse in crystal structure, composition, and microstructure including microcrystals or nanotubes. They are composed of tunnels or sheets of corrugated, double edge-shared (Ti,M)O$_\text{6}$ with varying lengths of such motifs, depending on the alkali-to-Ti ratio. The tunnel or the interlayer space allow many interesting physical properties such as ion/proton conduction, positive temperature coefficient of resistivity (PTCR) effect, etc. They also exhibit rich chemistry including intercalation, proton exchange, exfoliation, and reassembling, which are absent in denser alkaline titanate such as the BaTiO$_\text{3}$ perovskite. The nanosheets derived from layered alkali titanates display interesting dielectric properties with potential applications as pressure sensors and triboelectric nanogenerators (TENG). These materials therefore serve as a bridge for solid state chemistry and soft matter which is to be presented here.
We investigated the effects of external pressure on the superfluid density of s-wave isotropic superconductors by the BCS theory and semi-classical approach. The analytic results obtained the equation of superfluid density with pressure variables involved were derived. After that, the derived equations were numerically calculated in used to predict the experimental results in the superfluid density of hydrogen sulfide(H3S) and Lanthanum decahydride(LaH10) superconductors. We found that when temperature rises, the superfluid density drops however, the superfluid density is highest near zero temperature.
In this study, we used a two-band Ginzburg-Landau technique to investigate the surface critical magnetic field (Hc3) of magnetic superconductors, with the first band being anisotropic superconductors and the second band being isotropic superconductors. Following the calculation of the 1st Ginzburg-Landau equation, a surface critical magnetic field and its temperature dependent surface critical magnetic field were solved analytically using the variation method. Based on Changjan and Udomsamuthirun's temperature dependency model, we discovered that fits best with experimental data of K0.73Fe1.68Se2 superconductors, vicinity of the critical temperature.
The chromium aluminium nitride (CrAlN) thin films were deposited on Si by using reactive DC unbalanced magnetron sputtering method from alloy target and then annealed in air at different temperatures for 1 hr. The effect of annealing temperature on the structure, chemical composition, morphology, and hardness of the films was characterized by XRD, EDS, FE-SEM, and Nanoindentation, respectively. The as-deposited thin films were solid solutions of (Cr,Al)N with (111), (200), and (220) planes. The film composes of chromium, aluminium, and nitrogen in different ratios, with slight oxygen. The lattice constant was in the range of 4.104 – 4.145 Å. The average crystal size was increased from 17.2 to 22.4 nm with an increase in annealing temperature. The result from the FE-SEM technique was revealed that the as-deposited films annealed at the low temperature showed the dense morphology, and turned to be the compact columnar structure at the high temperature of more than 700 OC. However, when the annealing temperature was increased up to 900 OC, a slight increase in oxygen content in the films. The film’s hardness decreased from 67.3 GPa to 50.1 GPa with increasing the annealing temperature. In addition, the crystal structure or the oxides layer were not observed, showed that alloyed aluminium in the film can improve the oxidation resistance up to 900 OC.
Fusion reactions fuse light nuclei to form a heavier nucleus and release a huge amount of energy. In tokamaks and stellarators, this starts by heating magnetically-confined plasma until the light nuclei could overcome a Coulomb barrier and reach fusion conditions. Neutrons, one of the two products of the fusion reactions, are then captured with its kinetic energy converted to electricity generation. This MeV-scale reaction energy produces essentially no greenhouse gases. International-wise, fusion reactors at 1000-MW scale are envisaged as an alternative and GHG-free energy source in 2040s to 2050s. With such a plan for commercialization of fusion energy technology in a global stage, is Thailand ready to incorporate this advanced energy source in its energy mix by the time? Thailand aims to reach carbon neutrality in 205x and net zero emissions by 206x. Can fusion energy then contribute to strengthen the electricity stability in this bold plan? Is our ecosystem in terms of infrastructure, frontier sciences, research and development and human resource development for fusion technology up and ready to meet this grand demand? This contribution aims to address this question, summarize the preparation and project the ways forward.
Fueling in tokamaks is important for plasma confinement and operation. It can be realized by three main methods: gas puff, pellet injection, and supersonic molecular beam injection (SMBI). The SMBI can deliver the fuel more effective than the gas puff, and Thailand Tokamak 1 which is under development may potentially employed this fueling technique. In this work, we develop a simulation for studying the plasma dynamics during the SMBI in TT1. The simulation is based on the fluid model which includes the continuity equation, energy balance equations, momentum equation, continuity of fuel equation, and momentum of fuel. BOUT++ code is used to numerically solve these equations by a finite difference method in three-dimensional space. The initial results show that when SMBI of the hydrogen gas is launched into the plasma with a speed of 600 m/s, the electron density in the edge immediately increases due to the dissociation and ionization processes. The ion and electron temperatures subsequently decrease. The full analysis of the simulations hopes to benefit for designing of the injector and experimental plan for TT1 in the future.
Thailand Tokamak-1 (TT-1) will be the first tokamak setting up at Thailand Institute of Nuclear Technology (TINT) in Nakorn Nayok province, Thailand. In the initial operation phase, the hydrogen plasma will be performed with Ohmic heating. In the future, the neutral beam injection (NBI) will be used as the auxiliary heating to achieve the high-performance plasmas. The goal of this study is to investigate the beam ion birth profile generated by NBI using NUBEAM code, taking into consideration of the possible beamline geometry and beam ion energy in this machine. Furthermore, the full orbit motion of the model beam ions is analyzed by the collisionless Lorentz-Orbit (LORBIT) Code. The effects of the beam geometry including the tangency radius, shape, and power of the beam ion source will be conducted for assessing the beam ion confinement capability and engineering constraints. The detailed modeling of beam ion birth profile generated by NBI and the feasibility of NBI installation in TT-1 will be presented.
The 3D range-modulator is an innovation used in particle delivery systems that can create a highly conformal and homogeneous dose distribution in the target volume with mono-energetic beam, providing an option for high dose rate FLASH therapy (exploiting the Bragg peak) [1,2].
In the normal case, the modulators are positioned far away from the target in order to avoid the fluence ripples resulting from the periodic structure of the modulators [1]. To understand the fluence structure of protons induced by the 3D range-modulators and determine the minimum distance at which the fluence is homogeneous enough for the treatment, FLUKA Monte Carlo simulation package was used to observe the fluence distributions in the air or water after protons undergoing the modulators. The highest fluence ripple was spotted at a few centimeters from the modulators and then faded away as the distance increased, which can be described by the edge scattering effect and later by the blur-out of the overlapping contributions from the pins. Moreover, the dose distribution in water was investigated, particularly for small distances between the modulators and the water phantom.
Furthermore, the Monte Carlo results were compared with Gafchromic EBT-3 film measurements irradiated with a 3D-printed range modulator prototype and show a good qualitative agreement.
Prospectively, the strong dose inhomogeneity’s which appears in the proximal part of the target, could introduce a kind of ‘mini beam’ normal-tissue sparing by the 3D range-modulators.
Keywords: Proton therapy, 3D range-modulators, FLUKA Monte Carlo simulation, Edge scattering, Fluence and dose ripple
Ref.: [1] Yuri Simeonov et al 2017 Phys. Med. Biol. 62 7075, [2] Yuri Simeonov et al 2022 Biomed. Phys. Eng. Express 8 035006
The detection of gravitational waves (GWs) from the binary neutron star (BNS) has opened a new window on the gravitational wave astronomy. With current sensitivities, detectable signals coming from compact objects like neutron stars turn out to be a crucial ingredient for probing their structure, composition, and evolution. Moreover, the astronomical observations on the pulsars and their mass-radius relations put important constraints on the dense matter equation of state (EoS). In this talk, we will consider a homogeneous and unpaired charge-neutral 3-flavor interacting quark matter with (m$^{4}$$_\text{s}$) corrections that account for the moderately heavy strange quark instead of the naive MIT bag model. In addition, we study a strange quark star in the context of recently proposed 4D Einstein-Gauss-Bonnet (EGB) theory of gravity. However, this theory is not well defined in four-dimensional spacetime. Thus, we thoroughly show that the equivalence of the actions in the regularized 4D EGB theory and in the original one is satisfied for a spherically symmetric spacetime. We pay particular attention to the possible existence of massive neutron stars of mass compatible with M ~ 2M$_\text{⨀}$. Our findings suggest that the fourth-order corrections parameter (a$_\text{4}$) of the QCD perturbation and coupling constant α of the GB term play an important role in the mass-radius relation as well as the stability of the quark star. Finally, we compare the results with the well-measured limits of the pulsars and their mass and radius extracted from the spectra of several X-ray compact sources.
In this work R-symmetry defined in Wess-Zumino model is determined to be broken spontaneously within broken supersymmetric vacuum according to O'Raifeartaigh potential containing scalar fields of R-charges of 0 or 2. The analysis is done on Coleman-Weinberg effective potential at one-loop level. We find that there can be gauge symmetry breaking and R-symmetry breaking if $m_{X}^2<0$ and scalar field with R-charge other than 0 or 2 exists. The gaugino mass at one loop is in the order of $\Lambda\ln\Lambda$ scale but the renormailization is required.
Nonlinear dynamical systems, such as well-tuned recurrent neural networks, have proved a powerful tool for modeling temporal data. However, tuning such models to achieve the best performance remains an outstanding challenge, not least because of the complex behaviors that emerge from interacting microscopic constituents. Here, we consider a minimal model of two interacting phase oscillators coupled to a thermal bath and driven by a common signal. We quantify the memory and predictive capability of the system with the mutual information between the phases of oscillators and the signals at different times. We show that the interaction between oscillators can increase the information between the system and the signal. We attribute this behavior to an increase in the effective signal-to-noise ratio, resulting from a stronger correlation between the oscillators. Our work offers a first step toward a systematic approach to optimize interacting nonlinear dynamical systems for memorizing and predicting temporal patterns.
The locations of Earth’s auroral initial brightening and maximum poleward expansion are indicated as the magnetic latitudes, when the auroral breakup is expected to occur at magnetic local time between 22:00-1:00. Auroral images taken by the Visible Imaging System (VIS) and the Ultraviolet Imager (UVI) instruments onboard POLAR spacecraft reveal the variation of the locations that different auroral phases, initial brightening and maximum poleward expansion, took place. From different substorm events, the locations of the auroral phases appear to be highly variable. Quantitative analysis of the times and locations of both phases are presented via the time-series plots, keograms, and intensity profiles, for VIS; 557.7, 130.4, 391.4, 630.0 nm and for UVI; lbhl, lbhs, 130.4, and 135.6 nm emissions. For aurora associating with low-energy, “soft”, precipitating electrons, the responsive auroral emissions were shown in Polar/VIS 3914 Å, Polar/VIS 5577 Å, and Polar/VIS 6300 Å. On the other hand, the FUV auroras are presented in Polar/UVI images, representing the results of higher energy precipitating auroral particles (mostly electrons). Those visible auroras appear to be mostly expansive to higher latitude in comparison to the FUV auroras. The different locations of the auroral initial brightening and the less extensive FUV aurora are due to the different origins and distributions of high energy electrons in the magnetotail. Moreover, the location variation for different substorm events, in corresponding to the solar wind conditions, will be discussed.
Pulsars are rapidly rotating and highly magnetized neutron stars that radiate non-thermal radio beams from their poles. The radio emission of pulsars usually remains stable in the averaged intensity of ~1,000 pulses or more, but some pulsars exhibit interesting features in emission variations on short and long timescales. In this research, we report the phase-resolved pulse-to-pulse energy distribution of pulsar PSRJ1825-0935 and found that the pulse profile’s main component energy distribution is well described by a log-normal distribution. This pulsar has two different emission modes, B and Q modes, and we analyze the energy distribution of each mode energy separately.
Keywords: Pulsar, energy distribution
Maser flares are spectacular increases in brightness of astrophysical masers over a typical timescale of weeks to months. I consider a number of plausible mechanisms for generating these flares and determine the most likely mechanisms on the basis of timescale, variability index and ability to support periodic flares. The flare mechanisms considered are overlap of clouds in the line of sight, shock compression, rotation of non-spherical clouds and variations in the flux of pumping and background radiation. I briefly introduce the analysis of the flares observed towards a small number of star-forming regions, and discuss the correlation and anti-correlation of flares in different transitions and molecular species. I set out possible roles for the new 40-m TNRT in detecting and monitoring maser flares.
Jiangmen Underground Neutrino Observatory (JUNO) has a potential to indirectly detect dark matter (DM), observing neutrino events from annihilations of DM trapped by the gravitational force in the solar core. Weakly interacting massive particle (WIMP) DM candidate with mass $>$ 3-4 GeV has significant solar capture rate. In this work, we simulate JUNO neutrino events from the most dominated WIMP annihilation channel, $\tau\tau^{-}$. Given the high-energy neutrinos from massive WIMPs, we extend the neutrino-nucleon interactions in the detector to include Quasi-Elastic (QE) and Deep Inelastic scatterings (DIS).
The most challenging background events in the energy range above 100 MeV is the atmospheric neutrinos. The pulse shape discrimination (PSD) method is usually applied to distinguish between DM and atmospheric neutrinos. In this work, we apply Machine Learning (ML) techniques to classify the background events and rare dark matter signals. We found that the Support-Vector Machine (SVM) algorithm gives the best results. Using ML, the accuracy of DM- atmospheric neutrino events classification up to 99.2$\%$ with similar f1-score is achievable. On the other hand, only 92-93$\%$ maximum accuracy is obtained using linear classification criteria in 3 parameters space. The preliminary JUNO WIMP indirect detection sensitivity will also be presented.
We present the results of the most complete up-to-date spectropolarimetric survey of early-type peculiar (CP) stars in the association Orion OB1. The final sample contains 31 magnetic stars or 55% of the whole CP population in Orion OB1. For 14 CP stars, the longitudinal magnetic field exceeding approximately 500 G was detected for the first time. We show that the percentage of the magnetic CP stars and the field strength drop sharply with age. The mean longitudinal magnetic field in the young subgroup OB1b (log t=6.23) is confidently three times stronger than in the older subgroups OB1a (log t=7.05) and OB1c (log t=6.66). We conclude that the observed trends come from the different initial conditions in star formation regions. Meantime, in the Orion Nebula, a place with the youngest stellar population (log t < 6.0), the magnetic field appeared only in 20% of CP stars. Such occurrence drastically differs from 83% of magnetic CP stars in the nearby subgroup OB1c. We consider this effect an observational bias caused by the significant portion of the very young population with the signatures of Herbig Ae/Be stars.
The Sun is a well-known source of gamma rays emitted from cosmic rays during solar activity. It exhibits the variations over an approximately 11-year cycle due to the changes in the Sun’s magnetic field. In this work, we studied photons of energy of 0.1 – 10 GeV from the Sun disk detected by the Large Area Telescope (LAT) onboard of the Fermi Gamma-ray Space Telescope (Fermi), moving in the low-earth orbit at an altitude of about 550 km. We present the solar gamma-ray variations during the latest solar cycle between 2009 and 2021 of the latest versions of the LAT event selection (Pass 8). The results show the relationship between the solar gamma rays and the number of sunspots. This study provides a better understanding of the solar gamma rays, solar magnetic activity, and cosmic rays.
Although fault-tolerant quantum computation theoretically promises revolutionary benefits for computational science, the hardware development of a scalable fault-tolerant quantum computer is still in its infancy. In this talk, we will demonstrate near-term benefits of quantum or quantum-inspired computation from our two recent works [1-2]. First, using Quantum Alternating Operator Ansatz (QAOA), an algorithm that can be implemented on a near-term quantum device or simulated on a digital computer, we solve a realistic large-scale financial optimization problem experienced by a Thai bank. We show that the presence of the QAOA can improve the expected net profit returned to the bank (in a loan collection problem) by approximately 70%, compared to when the QAOA is absent from the algorithm [1]. Secondly, we discuss the benefits of quantum-inspired approaches in supervised machine learning. In particular, we recast a sentiment analysis problem with a recurrent neural network (RNN), which is difficult to analyze due to intrinsic nonlinearities, as an equivalent problem using a quantum tensor network, which can be efficiently and more easily analyzed on a digital computer. Using an entanglement entropy as a proxy for information propagation, we show that, contrary to a common belief that long-range information propagation is the main source of RNNs’ successes in sentiment analysis, single-layer RNNs harness high expressiveness from the subtle interplay between the information propagation and the word vector embeddings [2]. Our work sheds light on the phenomenology of learning in RNNs, using tools from many-body quantum physics.
References:
[1] https://arxiv.org/abs/2110.15870
[2] https://arxiv.org/abs/2112.08628 (New Journal of Physics, 2022)
Motivated by the current technology of solid-state qubits, which is one of the promising platforms for quantum computing, we are interested in the effects of random charge noises and how they can result in qubit decoherence. In this work, we model the charge noise as a random telegraph process (RTP), or a noise described by a two-state fluctuator, and analyze theoretical formulas for the RTP. We then construct a setup of a logical qubit with a qubit probe to measure the charge noise. Given the theoretical model, we investigate possible experimental parameters from the current experiments in the literature and numerically simulate the logical-qubit phase and its decoherence. Moreover, we analyze the recent phase-correction technique using Bayesian maps and show how the decoherence can be vastly improved.
NK acknowledges the support from the Development and Promotion of Science and Technology Talents Project (DPST). This work was supported by National Research Council of Thailand (NRCT) grant and N41A640120 and Australia-US-MURI grant AUS-MURI000002.
Machine learning techniques have been widely used for many complex systems including quantum systems with noisy environments. In this work, we are interested in a system of qubits affected by the random-telegraph noise that could destroy the qubit coherence. We construct a theoretical model including one logical qubit and one probing qubit, the latter of which can be measured at various times and with various measurement bases to collect information of the unknown fluctuating noise. We then use the recurrent neural network (RNN), in particular the Long short-term memory (LSTM) model, to process the measurement readouts obtained from the probe qubit and train the machine to learn how to estimate the correct phase of the logical qubit. We show numerical results of the random qubit phase affected by the random noise and the estimation accuracy from the LSTM. The accuracy does depend on different parameters of the machine as well as the qubit sensitivity to noise.
This work was supported by National Research Council of Thailand (NRCT) grant, N41A640120 and Australia-US-MURI grant AUS-MURI000002. SR also acknowledges the Faculty of Science for a Sri Trang Thong scholarship.
One of the main obstacles for implementing qubits in real experiments is the detrimental effects of environmental noises. Qubits in noisy environments can decohere quickly, i.e., losing their capability in processing quantum information. In this work, we are interested in analyzing the decoherence and possible ways to correct the phase errors due to the Gaussian white-noise. We consider a single logical qubit and investigate the qubit decoherence depending on different parameters of the white noise. We show analytical results of the qubit decoherence and verify them with numerical simulations. Moreover, we present a possible noise measurement and phase correction protocol that can be applied to estimate the effect of noise on the logical qubit. The quality of phase estimation does vary depending on the sensitivity to noise and the number of qubit probes used in measuring the unknown noise.
This work was supported by National Research Council of Thailand (NRCT) grant, N41A640120 and Australia-US-MURI grant AUS-MURI000002. TA also acknowledges Laser and Optic Research Group, Science and Technology Research Institute, KMUTNB for financial support.
In the past decades, organic light-emitting diodes (OLEDs) have been well commercialized due to the maturity of fluorescent (1$^{st}$ generation) and phosphorescent (2$^{nd}$ generation) emissive materials. However, both materials still are not perfect emitters for OLEDs. Recently, the 3$^{rd}$ generation of organic light-emitting materials has been developed by combining the key advantages of the 1$^{st}$ generation materials: simple structure and low cost and the 2$^{nd}$ generation materials: capable of up to 100% intrinsic quantum efficiency (IQE) due to its emission from both singlet and triplet excitons. The 3$^{rd}$ generation emissive materials still retain the basic structure of the 1$^{st}$ generation organic molecule, but they are structurally modified at the molecular level to harvest additional light emissions from triplet excitons, giving rise to high IQE, simple molecular structure, and low-cost emissive material. In this talk, I will focus on our recent developments in 3$^{rd}$ generation of organic luminescent materials capable of producing high IQE $\textit{via}$ several mechanisms, including thermally activated delayed fluorescence (TADF), hybridized local and charge-transfer excited state (HLCT), triplet-triplet annihilation (TTA), excited-state intramolecular proton transfer (ESIPT) and aggregation-induced emission (AIE) for high-performance organic light-emitting diodes (OLEDs). Our latest achievement in developing and utilizing fluorescence metal-organic framework (MOF) as advanced luminescent materials for OLEDs will be discussed. Finally, the study and development of novel solution-processable luminescent materials in which the essential elemental functions of an OLED, namely an intense solid-state light emission, electron/hole injection and transport capabilities, and solution-processability, would be incorporated by design into a single molecular architecture, will be illustrated. Some examples of solution-processable emissive materials will be discussed in terms of the structure-property relationships, with particular attention to the molecular design that affects the OLED device performance.
$\textbf{Keywords}$: organic luminescent materials, organic light-emitting diodes (OLED), thermally-activated delayed fluorescence (TADF), hybridized local and charge-transfer excited state (HLCT), triplet‒triplet annihilation (TTA), solution-processable luminescent materials, fluorescence metal-organic framework (MOF)
$\hspace{1 cm}$Controlling global warming is an essential social issue that humankind must solve in the future. With the Paris Agreement at COP21 (21st Conference of the Parties to the United Nations Framework Convention on Climate Change), Many countries try to limit future temperature rises to 1.5-2 ° C or less compared to pre- industrial levels. Furthermore, we are aiming to "pursue the 1.5 ° C effort target" agreed in November 2021 at COP26 in Glasgow, UK. In order to achieve such extremely high reduction targets, it is necessary to accelerate research and development in the energy field.
$\hspace{1 cm}$Tokyo Tech “InfoSy$\textbf{Energy}$ consortium” and “Academy of Energy and Informatics” were established as global research / education organization for industry-academia collaboration toward carbon-neutral society to develop the energy technologies by utilizing energy science and informatics. Twenty-five companies and 16 overseas universities are the members including over 70 Tokyo Tech professors and associate professors.
$\hspace{1 cm}$In the presentation, I will firstly explain the importance of nine priority research fields in InfoSy$\textbf{Energy}$ toward carbon neutrality, which are (1) Distribution energy systems controlled by using energy big data, (2) Technology for Renewable energy base-load, (3) Solar energy conversion, (4) Fuel cells, electrolysis, hydrogen energy, battery,,,energy storage, (5) Energy economy, Electricity free market, (6) Energy carriers, low carbon process by catalysts, (7) Hydrogen combustion, heat utilization, (8) Future energy technologies and (9)Tech trends, future scenarios, services in energy sector. I also introduce the present developmental status of the grid cooperated/distributed energy system named as “$\textit{Ene-Swallow}$” using big data and required hydrogen technologies like solid oxide fuel cell/electrolysis cell, and finally introduce “carbon air battery system” developed as an original energy storage system.
$\textbf{Keywords}$: energy system, big data, renewable energy, carbon neutrality, hydrogen energy, energy device
General oral presentation
This research is the WRF model initial application for wind investigation over Uttaradit Rajabhat University at Lamrang Thungkalo campus under some physical limitations. Its objective is to study weather simulation sensitivities specifically of wind characteristics over the campus on each domain sizes and on each season from selected time periods. Major three case studies are hot season case, rainy season case and cold season case. This experiment was conducted under two-way nested dynamical downscaling techniques, which nested domain (D02, 12km grid size) are within coarse domain (D01, 36km grid size). The National Centers for Environmental Prediction (NCEP) Final (FNL) operational global analysis data were used for initial and boundary conditions brought into WRF Preprocessing System (WPS). The cumulus physics process was controlled by Betts-Miller-Janjic (BMJ) cumulus parameterization, while simple ice scheme (WSM3) was used for microphysics. The NCAR Command Language (NCL) was utilized for graphic visualization. The results found that, WRF is firstly sensitive to domain size which finer domain can improve regional phenomena for coarser domain. Secondly, WRF can well simulate major winds in each case (southern wind in hot season, cyclonic flow in rainy season and northeastern wind in cold season). Thirdly, wind speeds in nested domain are mostly (greater than 50%) under light breeze (less than 3 m/s) agreed with all cases in coarse domain. Wind speeds In both domain were in accordance with TMD observed temporal variation. Fourthly, the vertical updraft was between -0.10 and 0.35 m/s which the highest speed was in hot season, while d02 enhance higher updraft than d01. Finally, high atmospheric stability can be detected from skew-T log P diagram during cold season case. Hence, WRF model can be applied to Uttaradit Rajabhat University at Lamrang Thungkalo campus to analyze the wind characteristics for all atmospheric levels.
A recent study has investigated and studied the growing body of research endeavors on human mobility during quarantine periods, employing a variety of methodologies and procedures. There are also numerous approaches to assessing human mobility using light pollution data. This study focuses on analyzing data on light pollution and the COVID-19 cases in the Philippines. The Visible Infrared Imaging Radiometer Suite (VIIRS) satellite data can be used to quantify light pollution as human mobility in the Philippines while the country has employed different quarantine classifications in the different regions. For this investigation, NASA's EOSDIS Worldview website provided the light pollution data while the Philippines' Department of Health (DOH) for the COVID-19 cases. It revealed that between early April and late August 2020, the number of COVID cases and light pollution increased. From September to January 2021, COVID cases decrease, while human mobility is almost constant. From February to April 2021 the number of COVID cases has immensely increased. This could be explained as an effect of the increased human activity between December 2020 and January 2021 which is the Christmas season in the country. Since August 2020, human contact has been intense, resulting in a rise in COVID cases that peaked between March and April 2021 and then declined in May 2021. As a result of this study's findings, light pollution VIIRS satellite images can be utilized to identify suspected COVID-19 cases in an area. When creating a full paper, there are numerous additional factors and variables to consider. Once the flexible quarantine period is extended, dates may be further investigated.
Home healthcare medical technologies have been gaining popularity and are more affordable in recent years. Exhaled breath analysis has potential in this field and the development of gas sensor technology has enabled us to build a small affable breath analysis device together with the electronic nose concept. In this work, a handheld breath analyzer was developed for monitoring body fuel utilization. A hybrid gas sensor array, including electrochemical, optoacoustic, and chemo-resistive gas sensors was used to provide accurate measurement of oxygen and carbon dioxide in exhaled breath. The bypass configuration volume flow measurement method was developed to fit in a small portable device. The result shows that both oxygen and carbon dioxide sensors are flow-dependent due to individual slow response time of each sensor type. The response of optoacoustic sensor is relatively slower than those of other sensor types. Thus, a mathematical model was developed to correct the individual sensor value to get more accurate value of body fuel utilization. The comparing protocol for known concentration of the oxygen and carbon gases with various flow rate was conducted and the model of transfer functions to reconstruct original gas concentration was proposed.
General oral presentation
The impact of the pandemic on the education sector is severe. It paralyzed the operations and administration of teaching and learning in response to fulfilling the need of the students to do an internship while at home. The Rizal Technological University (RTU) Center for Astronomy Research and Development (CARD) was able to redesign its internship program for students. The Physics, Astronomy, and Space Science Satellite Technology Virtual Internship Program (PASSTVIP) was developed to accommodate students who wanted to pursue research engagements at the convenience of their homes. The program aims to introduce the nature of physics, astronomy, and space science satellite technology through satellite databases and explore its relevance to research and development relative to the Philippine setting. The students were able to do data gathering, explore the Philippines using the data from the satellite of the National Aeronautics and Space Administration (NASA), and process these data thru Python coding with the assistance of their assigned mentors. The students were able to produce a ready Scopus conference paper.
The correlation was determined in the apparent links between attitude and motivation toward the PASSTVIP internships responses the interns. Both scales were supported, as well as the internship evaluation form. The participants were 168 undergraduate students who had undergone PASSTVIP from September 2020 to June 2021 in a synchronous and asynchronous setup. It showed that the PASSTVIP was rated as outstanding due to the uniqueness of exposure and the inspiring tasks from a satellite point of view. Students may have varying measures of their attitudes and motivation. As part of the evaluation form, open-ended questions demonstrate that students value satellite data and have explored the world through earth observations. They have also extended their learnings through coding analysis of earth data, geophysics, and earth observation which they also have cherished the research tasks. The students regarded their internship as exemptional due to its peculiarity, which involved physics, astronomy, and space science satellite technology training. While the students' attitudes and motivations are minimal, their responses to the internship program are impressive.
It is then proved that online internships can be done, applying scientific concepts with the aid of technology and equipment. Also, it imparts to make the students and the community explore the benefits and solutions that can be provided by space science and satellite technology in the country.
An experimental set for studying harmonic motion patterns was developed in this research. It was designed to be compact and easy to use. It employs sensors in general smartphones to track trajectory patterns of the object moving in both simple and damped harmonic motions. This experimental set can be remotely controlled and collected trajectory data. The data and patterns of trajectory of the studied object can also be real-time displayed and collected by other devices (computers, tablets or smartphones) which students can use for more analysis. Testing the functionality of the presented experimental set, it was found that there was a good consistency between the trajectory patterns collected from the experimental set and simulated from the theory. To evaluate the usage of the experimental set, it was applied to Physics classes. It was found that the students had improved their understanding of harmonic motion pattern by 34.50 percent. These results show that the proposed experimental set can be used for studying harmonic motion patterns effectively.
The teaching of uniform circular motion in high school Physics consists of a combination between theoretical background and experimental method. In particular, the experimental study can emphasize the concept of centrifugal force for the object moving in a circular path. The experiment set has been developed to study the relationship between the centrifugal force and the moving period. However, the effect of friction in the conventional experiment set has been neglected leading to the deviation of the expected results. In this study, we have developed the circular motion experimental set with the reduction of friction between a hollow tube and a string. The plastic tube in the conventional experiment set was replaced by an aluminum rod to reduce friction at the surface connected to the string. By collecting the experimental data, the mass moving in the circular path was evaluated and showed high accuracy with a deviation of 0.58%. In contrast, a high discrepancy (up to 35%) was observed in the conventional setup due to the surface roughness of the plastic tube. Therefore, the results obtained from our studies can be used to enhance student learning on the uniform circular motion subject in high school.
The electronic properties of random networks of single-walled carbon nanotubes (SWCNTs) are probed by 1/f noise characteristics in a frequency range of up to 109 kHz as a function of bias voltages and the number of nanotubes deposited between asymmetrical-work function metal electrodes. The measured current-voltage characteristics of the devices exhibit rectifying and ohmic behaviour revealing Fermi-level depinning and pinning of the metal and one-dimensional contacts, respectively. The noise amplitude ($A$) characterizing the 1/f noise levels and the power-law exponents ($\beta$) of the devices are investigated in both reverse- and forward-bias voltages for different nanotube depositions at ambient temperature. In a few nanotube depositions, $A$ is found relatively small (10^-5 to 10^-7) and the extracted $\beta$ is exceeded 2 in the reverse bias, suggesting that charge-carrier trapping by the formation of the Schottky barrier is exhibited at the metal-nanotube contacts. Furthermore, as the number of nanotubes increases the device-channel resistance drops rapidly as the densely-packed inter-tube junctions are formed between the two electrodes. The observed A is found 1.5 times higher than that obtained in the devices with fewer nanotube depositions. This result shows that the 1/f noise of the SWCNT devices is dominated by the device resistance due to the inter-tube junctions under a finite bias. Our experimental observation agrees well with that of the previous works using carbon nanotube films for implementing hybrid-silicon Schottky barrier photodetectors.
Free-standing reduced graphene oxide (rGO) has been gaining popularity for its use in supercapacitors and battery applications due its facile synthesis, multi-layered structure, and high-current carrying capacity. Pertinent to the successful implementation of such applications, however, is the need to develop a thorough understanding of the electrical properties of such materials when subject to high applied electric fields. In this work, we undertake a detailed study of high-field electrical properties of mm-scale, lightly-reduced, rGO papers. Our results reveal that the I–V curves exhibit substantial nonlinearity with associated hysteresis that depends strongly on the applied electric field. The nonlinear behaviour which was interpreted using conventional transport models of Fowler–Nordheim tunneling and space charge limited conduction revealed that while these models provided good qualitative fits to our data, they were quantitatively lacking, thus leaving the issue of high-field transport mechanisms in rGO open for debate. Careful I–V cycling experiments with measurement time-delay introduced between cycles revealed that the observed hysteresis contained recoverable and non-recoverable parts that we identified as arising from charge trapping and Joule heating effects, respectively. Time-dependent measurements showed that these effects were characterized by two distinct time scales. Importantly, the Joule heating was found to cause a permanent conductivity improvement in the rGO via the 'current annealing' effect by effectively eliminating oxygenated groups from the rGO. The analysis of the electrical breakdown in our samples resembled a thermal runaway-like event that resulted in premature damage to the rGO. Finally, we investigated the low-field resistivity in the 80 K–300 K temperature range. The reduced activation energy analysis revealed a robust power law behaviour below 230 K, while deviating from this trend at higher temperatures. For samples that received current annealing treatment, a reduced value for the power law exponent was obtained, confirming the effective lowering of disordered regions.
Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this work, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much larger than (e^2)/h. This violation of one of the fundamental tenets of mesoscopic physics dramatically demonstrates how local considerations can be overwhelmed by remote signatures in phase-coherent conductors.
Nowadays, clean and sustainable energy with flexible energy storage devices has gained more attention. Therefore, among various energy storage systems, flexible supercapacitors (SCs) are standing out due to their high capacity, high power density, high flexibility, and long cyclic lifetime. In this work, the electrochemical performances of carbon nanofibers decorated by TiO2 hollow nanospheres (hTiO2-CNFs) supercapacitor electrodes are studied. The hCNF-TiO2 were synthesized using an electrospinning method followed by heat treatment. The inner structure, morphology, crystal structures, distribution of elements, and specific surface areas of the samples were characterized by Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscope (FE-SEM), X-Ray Diffraction (XRD), Energy-dispersive X-ray spectroscope (EDS), and Nitrogen adsorption/desorption isotherms (BET), respectively. In addition, the electrochemical properties were studied by using Cyclic Voltammetry (CV), Galvanostatic Charge-Discharge (GCD), and Electrochemical Impedance Spectroscopy (EIS). It was found that the specific capacitance of the bare-CNF electrode (170.03 F g-1 at a current density of 0.5 A g-1) was improved after being embedded with 5 wt% TiO2 hollow nanospheres (185.70 F g-1). Furthermore, the hCNF-TiO2 exhibits high cycling stability, retaining 98% after 2000 cycles. This shows that TiO2 hollow nanospheres can help enhance the efficiency of the CNF electrode. As a result, this might pave a way for the development of high-performance flexible supercapacitors.
Pretreatment processes including physical polishing (PP), wet-chemical polishing (WP), and thermal annealing for smoothing a surface of copper (Cu) foil were optimized for high-quality graphene growth. In this work, the cu foil with a small thickness of 25 µm has been used as a substrate. Preliminarily, a substrate surface was smoothed by the PP process using Brasso as a polishing substance. The substrate was next etched by the WP process using phosphoric acid $(H_{3}PO_{4})$ as an etchant in order to further reduce a surface roughness and remove surface contamination. For the condition of WP process, an etchant concentration was varied from 30 to 60%, and an etching period was adjusted to 60, 90, and 120 s. Finally, the substrate was thermally annealed with a nitrogen gas for 10 min before growing graphene. An annealing temperature was varied from 860 to 940 ºC. After the pretreatment processes, graphene was grown on the prepared cu foil substrate by direct-liquid-injection chemical-vapor deposition (DLI-CVD) technique using cyclohexane $(C_{6}H_{12})$ as a carbon precursor and nitrogen as a carrier gas. A growth temperature was fixed constantly at 920 ºC, and $C_{6}H_{12}$ was injected into the reactor with a flow rate of 0.5 g/min and pulse frequency of 0.5 Hz for 6 min. The surface morphology of Cu foil observed by optical microscopy exhibits that the substrate treated by PP and WP with the conditions that $H_{3}PO_{4}$ concentration is 45% and etching period is 90 s provides the smoothest surface without being damaged by the etchant. When the annealing temperature is assigned to 880 ºC, the room-temperature Raman spectra measured with a 473-nm excitation shows that an intensity ratio of 2D to G peak $(I_{2D}/I_{G})$ is enhanced above 2. This result indicated that a monolayer graphene could be successfully formed at this optimized temperature.
In this work, the dielectric and non-Ohmic properties of $Ca_2 Cu_2-x Ge_x Ti_4 O_12$ ($CaCu_3Ti_4O_12$/$CaTiO_3$ composite) ceramic with additions of $GeO_2$ (x = 0, 0.025, 0.050 and 0.100) were prepared using a solidstate reaction method. X-ray diffraction technique was used to confirm the second phases of CaCu3Ti4O12 and CaTiO3 phases was detected in all the ceramics. The slight decrease in the grain sizes of $Ca_2 Cu_2-x Ge_x Ti_4 O_12$ ceramics can be observed using a scanning electron microscopy. The results revealed that ceramics sintered at 1060 °C for 6 h exhibited slightly different dielectric permittivity (~ 1784 – 2645), and the dielectric loss tangent was still very low (~ 0.036 – 0.018) at 1 kHz. This should be associated to insulating grain boundaries with activation energies of 0.80 eV by substitution of $Ge^(4+)$ for x = 0.050. The electrical responses of grains boundaries and internal interfaces were investigated using impedance spectroscopy. Strongly enhanced dielectric responses and variation in nonlinear electrical properties can be well described based on the electrical responses at internal interfaces of the ceramic composites.
Vanadium dioxide (VO2) is a material which has a special characteristic that can change its properties drastically called metal-Insulator transition (MIT). The MIT of VO2 occurs at temperature about 68๐C under atmospheric pressure which change its phase from monoclinic to rutile phase, result in their different properties and structure. This characteristic of VO2 can be used for application such as smart windows[1]. Moreover, some material can be used to improve VO2 film quality. In this work, bilayer-graphene were deposited on top of VO2/Al2O3 of 50 nm and 100 nm VO2 and were studied via temperature-dependent Raman spectroscopy technique. The results from Raman spectrum indicate that the lattice parameter mismatch between bilayer-graphene and VO2 induce compressive strain on graphene and in-plane tensile strain on VO2 according to the observed blue shift of VO2 Raman modes. From the temperature-dependent Raman results, the monoclinic VO2 Raman peaks diminished as temperature reach 60-65°C while the TMIT measured by temperature dependent resistance of bare VO2 is equal to 70°C. Moreover, an unexpected behavior from graphene can be observed in graphene/VO2. For graphene/SiO2 G-peak position tends to red shift as temperature increase[3]. However, the G-peak position observed from graphene/VO2 structure begins with red shift and turn to blue shift at ~60°C instead of only red shift.
References
[1] Y. Cui, Y. Ke, C. Liu, Z. Chen, et al. Thermochromic VO2 for Energy-Efficient Smart Windows. Joule, Volume 2, Issue 9-2018, 1707-1746. https://doi.org/10.1016/j.joule.2018.06.018
[2] Zhou, H., Li, J., Xin, Y., Cao, X., Baoa, S., and Jin, P. (2015). Enhanced optical response of hybridized VO2/graphene films. J. Mater. Chem. C, 3(19), 5089-5097. doi:10.1039/C5TC00448A
[3] Wang, W., Peng, Q., Dai, Y. et al. Temperature dependence of Raman spectra of graphene on copper foil substrate. J Mater Sci: Mater Electron 27, 3888–3893 (2016). https://doi.org/10.1007/s10854-015-4238-y
This work study the effects of magnetic field topology of polywell fusion device on electron confinement time. Several polywell designs are used including a cube configuration (6 coils), dodecahedron configuration (12 coils), double-layer configuration (14 coils) and disco configuration (26 coils). The results of magnetic field structure are investigated by using numerical simulations based on finite element method. In addition,the effect of electrical current in each coil on the observe magnetic field is also investigated. Electron beams are injected into each configuration in order to determine the decay behavior of electron numbers. The probability of loss is defined with loss cone, which can be used to predict what configuration yield the most electron loss. It is found that the increase of coils current does not affect the probability of loss. However, it demonstrates that the dodecahedron configuration yield highest probability of loss. The confinement time study shows that the dodecahedron configuration yields better confinement than cube and double-layer configuration. The disco configuration yields the best results, confining electrons for the longest time of about 20 μs.
The heat and particle transport equations are used to study the formation of an edge transport barrier (ETB) in a tokamak plasma based on the two-field bifurcation concept. These equations are simultaneously solved by a numerical method using the BOUT++ physics framework resulting in plasma pressure and density profiles as a function of time and plasma radius. The transport effects include both neoclassical and anomalous effects, where the latter can be suppressed by the flow shear mechanism. The flow shear is proportional to the multiplication of the pressure and density gradients. The main heat and particle sources are localized at the center and edge of the plasma, respectively. The result shows that when the heat or particle source surpasses its threshold value, there will be the formation of the ETB at the plasma edge. As a result, pressure and density at the center are enhanced. Moreover, the effect of varying neoclassical and anomalous transport coefficients on the pressure and density profiles is also investigated. It is found that as the transport values are increased, the plasma performance drops, and at some point, the plasma can no longer form an ETB. The results are compared with those solved by MATLAB from previous research work for benchmarking purposes. This research is supported by TSRI Fundamental Fund project number 91526.
This work studies the phenomenon of neutron transport simulation and the ratio between incident neutrons and produced tritium breeding of fusion blanket on various materials. The aim is to investigate the local Tritium Breeding Ratio (TBR) after neutrons pass through 5 meters thickness of the 30 degrees angle of cylindrical-shape breeding blanket of different materials using GEANT4 simulation framework. For all simulations, G4HadronPhysicsQGSP_BIC_HP Physics list, materials i.e., 6Li+7Li, 6Li, Li2O, Li17Pb83, Li4SiO4, Li2ZrO3, and Li2TiO3 are used. The results show that the local TBR of Li2O and Li17Pb83, two of the most popular materials, are 0.9595 and 0.96091, respectively, for 0.025 eV neutron energy at room temperature. For 50 eV neutron energy, the local TBR of Li2O and Li17Pb83 are 0.35613, and 0.36256 respectively. Their local TBR decreases when faster neutrons pass through the blanket. Still, they stand out from other components, i.e., Li4SiO4, Li2ZrO3, and Li2TiO3. In addition, temperature effects on the local TBR is also investigated. It is found that higher temperature only slightly decreases the local TBR on all materials. This research is supported by TSRI Fundamental Fund project number 91525.
Strange and charmed baryon pair productions in proton-antiproton collisions are studied in effective Lagrangian and Regge approaches. Unknown parameters from both models are determined from the comparison with the existing data for strangeness productions. Then, we predict charm production cross sections by extrapolating the amplitudes for strangeness productions to those for charm. From our study, charm production cross sections are about $10^{-4}$ to $10^{-5}$ times smaller than those of strangeness productions. Our results can be tested in the future experiments at $\bar{\text{P}}$ANDA.
The masses of low-lying S-wave and P-wave charmonium mesons are evaluated in a constituent quark model (CQM) where the Cornell-like potential and Breit-Fermi interaction are employed. All model parameters are imported from the previous work of S-wave meson mass calculation. Two sets of complete bases are constructed by using the harmonic oscillator wave function, and the Sturmian wave function, respectively. In the calculations, the bases size is $N=38$, and the length parameters of the complete bases are adjusted to determine the eigenvalues. The thus established model with one set of parameters may be applied to study higher excited meson states as well as tetraquark systems.
Fluid-Gravity correspondence is an effective theory of AdS-CFT correspondence in a long-wavelength regime. The correspondence represents the map between Einstein equations in AdS bulk and hydrodynamics on the boundary. In particular, we demonstrate the construction of the energy-momentum tensor of the fluid on the boundary from various types of black holes in the bulk of AdS spacetime up to the first order in derivative expansion.
Although the discovery of the 125 GeV Higgs boson has confirmed the Higgs mechanism of the Standard Model (SM), many theories beyond the Standard Model (BSM) has been introduced to solve several phenomena not explained by the SM. One example is the Two Higgs Doublet Models (2HDM), the simplest extension of the SM Higgs sector, that predicted the existence of additional Higgs bosons. In this study, we investigate the use of supervised learning of machine learning method which is hypothesized to be more effective than traditional cut-based method, to search for BSM Higgs bosons decaying into bottom-antibottom quark pairs ($H\rightarrow b b$), the dominant Higgs boson decay channel. We train machine learning models to classify whether events detected by the detector belongs to $H\rightarrow b b$ process (signal) or multijet process (background) based on simulated proton-proton collisions within the Compact Muon Solenoid (CMS) detector. The evaluation matrix is calculated to compare the classification efficiency of models using Neural Networks (NN) and Tree based models. The results show that machine learning models can classify signal and background processes with significant improvement and can be used as signal-background discriminator for further statistical analyses searching for BSM Higgs bosons.
Proton computed tomography (pCT) is a medical scanning technology suitable for treatment planning of proton therapy. Suranaree University of Technology, together with the Bergen pCT collaboration, is currently constructing a pCT prototype for clinical trials. This study aims to reconstruct proton tracks generated from a Monte Carlo simulation which can be applied to 3-dimensional image reconstruction. Our simulation is built on Geant4 via Gate toolkits. We analyze a simultaneous irradiation of the telescope with the KCMH proton beam implementing a track following algorithm written in python. Hereby, each node or hit point will identify its subsequent node within the next detector layer as the one within minimum distance. We fix the ratio of the number of reconstructed track hits to Monte Carlo hits at 75%. The pencil beam at 220MeV has 3.3 mm of spot sigma. With 200 primary protons in simulation, the reconstruction efficiency can achieve 84%.
Quantum annealing is an optimization method conventionally performed in an adiabatic fashion. Adiabatic quantum annealing (AQA) gradually changes the Hamiltonian so that the system stays in an instantaneous ground state of the Hamiltonian at all times. However, this slow process could hamper computational speedup. In contrast, diabatic quantum annealing (DQA) allows transitions between the ground state and excited states during the anneal. Hence the annealing process can take less time, enabling quantum speedup. In theory, DQA could be achieved by exploiting the interference effect from the Landau-Zener-Stückelberg (LZS) transition as a shortcut to adiabaticity. Our goal is to execute the LZS experiment on high-Q superconducting flux qubits. Typically, the LZS experiment is performed in the steady state, using a continuous-wave drive. The result of averaging many drive cycles makes the definition of the environmental effect challenging. Instead of using a continuous-wave drive, we aim to use a single pulse sequence to drive the system through the avoided crossing just one time. This technique creates a sensitive probe for decoherence and gives better visibility of the environmental impact on the qubit. Here, we characterize and calibrate a superconducting device consisting of a flux qubit, a quantum flux parametron, and a tuneable resonator in a dilution refrigerator, which cools the device down to 10 mK. Device calibration is performed to account for the crosstalk among the qubit, the quantum flux parametron, and the tuneable resonator. Qubit two-tone energy spectroscopy is subsequently derived using continuous- wave measurements. Then, we establish a pulse readout measurement configuration for the LZS experiment towards DQA. Moreover, we investigate the impact of the readout pulse length when measuring a dispersive readout resonator. The results could suggest a suitable pulse length for the subsequent Rabi oscillation experiment.
Quantum computing is an interesting research and can be applied to many research areas, such as machine learning, optimization, and especially quantum simulation. In this work, we simulated the ground state energy of diatomic molecules: O2 and CO. We designed the ansatz for symmetric diatomic molecule, which is the O2 and asymmetric diatomic molecule, which is the CO. The designed quantum circuit was implemented in IBM quantum, and the results of the ground state enegy simulation can be compared with the experimental results.
We reanalyze the problem of a 1D Dirac single-particle colliding with the electrostatic potential step of height $V_{0}$ with an incoming energy that tends to the limit point of the so-called Klein energy zone, i.e., $E\rightarrow V_{0}-\mathrm{m}c^{2}$, for a given $V_{0}$. In this situation, the particle is actually colliding with an impenetrable barrier. In fact, $V_{0}\rightarrow E+\mathrm{m}c^{2}$, for a given high relativistic energy $E\,(
Quantum emitters (QEs) play crucial roles in quantum technology applications, especially for quantum key distribution. Recently, color-center defects in a two-dimensional hexagonal boron nitride (hBN) have revealed many promising properties, such as high brightness, operation under room temperature, and broad emission wavelengths, demonstrating that they are attractive candidates for QEs. Thus far, most experiments found the emitter at 2 eV range influenced by C-based defects; however, the nature of defects for such QEs remains unknown and uncovered. In this work, we investigate 2 eV emitters using density functional theory (DFT) with Perdew-Burke-Ernzerhof (PBE) functional. We aim to theoretically characterize the origin of the electronic transition and to further identify the possible 2 eV defects. Four different types of defects, namely $C_BV_N$, $C_BC_N$, $N_BV_N$, and $O_BO_BV_N$ have been unraveled. Our results suggest that all of studied defects except for $C_BC_N$ are likely 2 eV emitters whereas $C_BC_N$ is more likely to be a 4 eV emitter. This paves the way that not only C-based defects, but also non C-based defects emit at 2 eV. Furthermore, our defect formation energy calculation predicts that $C_BC_N$ is the most thermodynamically favorable for synthesis, followed by $N_BV_N$, $O_BO_BV_N$ and $C_BV_N$.
The determination of the refractive index (RI) and concentration of ternary mixture of glucose, ethanol and water is demonstrated by smartphone platform based on the detection of the refractive index by using surface plasmon resonance (SPR) principle. The optical coupler has been specially designed for coupling the light from smartphone screen to excite SPR on the thin gold layer in contact with solutions and to guide the reflected light to the smartphone camera used as the detector. For this work, the RIs of glucose and ethanol solution was determined by using image processing technique; the captured images of each individual solution were processed to the SPR spectra which indicates the significantly different SPR shift corresponding to the RI changes. In order to estimate the individual concentration of ternary mixture, at least two independent calibration equations are needed. Hence, two color light sources with different color intensity denoted as color1 (R=255, G=0, B=0) and color2 (R=255, G=100, B=0) were used to construct the calibration equations of two binary solutions. Calibrations ware carried out using four ethanol-water and glucose-water solutions which were providing a linear response in the refractive index range of 1.341– 1.361 RIU (R2 = 0.977-0.992) with the resolution of 0.14 mL/dL, and 0.04 g/dL for ethanol-water and glucose-water solutions, respectively. As a result, the estimated concentration errors for each element of the prepared ternary solution were found to be less than 5%. Accordingly, our work demonstrates the successful experiment for the determination of concentration of ternary mixture on unmodified smartphone which provides a simple and reliable portable device.
General oral presentation
With the growing concern of climate change and the reduction of CO$_{2}$ emission, the Advanced Nanomaterials for enhancing Sustainable Energy and Environment in Dong Phayayen - Khaoyai World Hertage (or ANSEE project) was initiated. Prototypes of green energy applications, especially relating to customized batteries, have been installed and tested in the Khao Yai National Park and farms near the park. The applications include hybrid-off-grid solar system for tourists and office, EV motorcycles, EV charging stations and off-grid solar systems for farming. In this talk, we will describe about the customization processes relating to energy storage and the environmental/financial/social benefits.
$\textbf{Keywords}$: renewable energy, energy storage, battery application, CO2 emission, environmental sustainability
Net radiation can be used for different purposes especially for studying the energy or radiation balance, which can be further analyzed to investigate a global warming. In order to utilize these applications, it is necessary to know the amount of net radiation in that area. This can be done by installing a net radiometer for measuring the net radiation. However, there are few monitoring stations of net radiation compared to a global solar radiation in Thailand. Therefore, this research aims to analyze a statistical characteristic of the measured net radiation and to develop a model for estimating the net radiation from the global solar radiation at four solar monitoring stations in the main regions of Thailand, namely Chiang Mai, Ubon Ratchathani, Songkhla and Nakhon Pathom during the year of 2017 to 2021. The results showed that the average net radiation of these stations was between 8-12 MJ/m2. The relationship between daily and monthly average daily net radiation and global solar radiation was found to be a linear. After that, the developed model was validated by comparing the estimated and measured net radiation. The discrepancy between the calculated net radiation and that obtained from the measurements was presented in terms of root mean square difference (RMSD) and mean bias difference (MBD) ranged from 6.98% to 16.03% and -1.82% to 6.77%, respectively.
High-efficiency perovskite solar cell (PSC) normally utilizes metals such as gold or silver as the electrode to achieve the highest power conversion efficiency (PCE) as possible due to their high charge transfer properties. However, there are some disadvantages of the metal electrodes such as high price, high-temperature deposition requirement, and low hydrophobicity. Recent studies show that carbon has a great potential for being PSC’s electrode due to its adequate conductivity, proper work function, flexible nature, hydrophobicity, low cost, and low energy input for fabrication. This work focuses on improving a commercially available carbon electrode material for perovskite solar cell by adding carbon black to increase its flexibility and conductivity, yielding reduction of resistivity by 50% measured with a 4 point probe. To further improve mixability between the carbon paste and the carbon black, different solvents were explored. Smaller pore size, smother morphology, better charge transfer, and homogeneous conductance distribution of the carbon film were achieved. The power conversion efficiency more than 15% with little hysteresis was demonstrated with the enhanced carbon electrode.
Western North Pacific is the most active TC Basin globally as the season runs whole year round and Sun is the main driver of Earth's Climate, although climate drivers are the ones that affect the typhoon season. As presented in the literature studies, there are few research studies have investigated the relationship between SSN and Tropical Cyclones, but it is done in a specific location or basin. This research will fill in the gap of finding the relationship between SSN and TC in the Western North Pacific as part of the recommendation of the said studies. Datasets that were used were from Japan Meteorological Agency, Solar Influences Data Analysis Center, and National Oceanic Atmospheric Administration. The researcher investigated the relationship between Solar Activity and Tropical Cyclone Frequency with the use of Pearson Correlation, Linear Regression Analysis, and T-Value. The researcher found out that the results of the analysis are mostly in negligible correlation and not significant in terms of overall season, Solar Minimum and Maximum basis, and ENSO phases which concludes that a). there is no overall significant correlation between SSN and WNP-TCF, b). there is no significant correlation between SSN and WNP-TCF during Solar Minimum and Solar Maximum, c). there is no significant relationship between SSN and WNP-TCF during El Nino and La Nina. Thus, this study found out that Sunspot Number doesn’t have much effect to the Tropical Cyclone Frequency in the Western North Pacific Basin and likely that Anthropogenic Aerosols and Climate Oscillators plays the role in the Tropical Cyclone Activity.
General oral presentation
Throughout the COVID-19 pandemic, SARS-CoV-2 has been mutated several times into new variants. Some of them are classified as variants of concern (VOCs) by the World Health Organization, such as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.1.529). In this work, we developed an extended Susceptible‐Exposed-Infection‐Recovered model with cross-immunity between two co-circulating strains to investigate the transmission and competition of two VOCs, Delta and Omicron, that recently emerged in Thailand during the mid and late 2021. Here, the basic reproduction number of the Omicron variant was estimated higher than that of the Delta variant. The results showed that the Omicron variant has a significantly faster transmission, leading to a higher number of infected cases than the Delta variant. Moreover, lowering cross-immunity induced by primary infection also increases the re-infection rates. These results suggested that the capacity of transmission illustrated by the basic reproduction number and cross-immunity play an important role in determining the competition and equilibrium of transmission.
COVID-19 vaccination is an important role to reduce the chance of infection and lower the risk of hospitalization and death. However, the vaccination is far less effective with the recent emergence of the Omicron variant. In addition, vaccine protection after vaccination may wane over time, thus receiving additional booster doses is significant to maintain the protection. In this work, we applied an extended SEIR model with vaccinations to investigate the impact of the vaccination rate of primary and additional doses on the spread of the COVID-19 pandemic in Thailand. The results shown that the booster vaccination rate has a major impact on the reduction of infection. These results suggest that the high coverage of booster vaccination remains crucial for reducing the spread of COVID-19.
The first SARS-CoV-2 infections were discovered in Wuhan, China, and then the virus became the pandemic known as “COVID-19”. In Thailand, the COVID-19 situation is still on going and is extremely serious in the central region of the country. To understand the pandemic in Thailand, we investigated the association of three variables, temperature, relative humidity, and the concentrations of PM 10, on the number of cases. We applied a long short-term memory model (LSTM) to predict the number of cases from these associated factors, in the central region of Thailand. This study observed the COVID-19 reported cases from Open Government Data. The meteorological variables data were obtained from the Global Surface Summary of the Day (GSOD), and the PM 10 data was obtained from the World Air Quality Index (WAQI). The results showed that the variables related to the number of COVID-19 cases and could be used to predict the number of cases. We also studied the effect of time lags to the number of cases.
Many airborne infections can easily be transmitted from a patient through coughing, sneezing, or even talking. This encourages awareness of wearing a mask as a protection. This research demonstrates the dispersion characteristics of exhaled airflow through the different ways of protection using background-oriented schlieren (BOS) technique to visualize the air flow around facial area of a demonstrator. Circumstances such talking and coughing under the different modes of protection were video recorded and processed with a MATLAB PIVlab toolbox to visualize the characteristics of the airflow around facial area. It was found that there is always air leakage out from protected masks while coughing in which surgical mask performed poorly when compared with N95 masks. Nonetheless, wearing mask can significantly reduce the speed of airflow.
Nonetheless, there is a small amount of dispersion of the airflow from the protected circumstances. The characteristics of each dispersion relate to the shape of the mask. The high potential of the protection can be respectively classified as N95 mask without valve, N95 mask with valve, and surgical mask. On the other hand, all protection has a potential in reducing airflow dispersion comparing to unprotected circumstance.
Convection is one of the heat transfer mechanisms in which heated fluid expands and rises while the cooled fluid shrinks down. The air convection occurs naturally but difficult to be observed when there is a slight difference between temperature of heated object and the ambience. Schlieren imaging technique is mostly used to visualize the motion of the fluid itself. This method, however requires high accuracy and expensive optic devices. Background-oriented schlieren (BOS) is an optical measurement technique where the velocity field of the viewing region could be visualized. In this study, air flow field around ice cube, hand and candle flame were constructed and the converted air speed were measured using Particle Image Velocimetry (PIV) technique from MATLAB PIVlab toolbox. The results showed that the BOS technique can be similarly used to visualize the air convection around the testing objects when comparing to schlieren technique yet significantly costs less in expenditure.
In this talk, I will present my ongoing research on the theme of bacterial cellulose nanocomposites. Bacterial cellulose (BC) is a natural polymer with a three-dimensional network of nanofibers. It is produced by cultivation of certain types of bacteria strain. The structure and properties of BC are very unique. It exhibits remarkable mechanical properties, porosity, water absorbency, moldability, biodegradability, and excellent biological affinity. Moreover, it possesses highly porous nanostructure with very high surface area, which makes it an ideal substrate to host other nanomaterials. Several types of nanoparticles have been incorporated in BC to improve the characteristics and properties. In my group, we have focused on impregnation of various kinds of magnetic nanoparticles in BC to make flexible magnetic membranes, which can be utilized for several applications, such as actuators, sensors, electromagnetic shielding, information storage, and anti-counterfeit materials. Furthermore, by pyrolysis, BC transforms into carbon nano-sponge, which can be used for heavy metal adsorption or oil adsorption. I will summarize the work I have been doing in the past 4 years, and an outlook for the future work.
Titanium nitride (TiN) thin films were deposited on Si substrates by reactive DC unbalanced magnetron sputtering from metallic Ti targets. The effect of N2 flow rate, in the range of 1.0–4.0 sccm with 1 sccm increment, on the structure of the as-deposited TiN films was investigated. The crystal structures were identified by the GI-XRD technique. The thicknesses, microstructures, and surface morphologies were observed by the FE-SEM technique. The elemental compositions were evaluated by the EDS technique. The hardnesses were measured by the nano-indentation technique. The film’s colors were measured by the UV-VIS spectrophotometer. The results showed that the as-deposited films had an fcc structure with (111), (200), (220), and (311) planes. The lattice constant and the crystallite size were ranging from 4.211–4.239 Å and 17.8–24.6 nm, respectively. The as-deposited films showed a nanostructure with a crystal size of less than 25 nm. The thickness of films decreases from 1254 nm to 790 nm with increasing in the N2 flow rate. The elemental composition of the films
(Ti and N contents) depended on the N2 flow rates. The cross-sectional analysis of films by the FE-SEM technique showed a compact columnar structure. The hardness of films measured by the nano-indentation technique was increased from 4.5–19.4 GPa with increasing in the N2 flow rates. The color of the film was measured in the CIE Lab* system showing that the film deposited with optimal N2 flow rates was close to the color of 24K gold.
Organic-inorganic hybrid perovskites are currently some of the most promising photovoltaic materials to produce highly efficient and cost-effective solar cells. Currently, many approaches have been proposed to prepare high-quality perovskite layers. The antisolvent technique is an effective and widely used method that can be done by dropping antisolvent into the rotating precursor surface during the spin-coating process. This technique is used to rapidly decrease the precursor's solubility, leading to a crystal-like uniform and dense perovskite layer. In the development of perovskite solar cells, three main areas are being developed: efficiency, stability, and reproducibility. This work concentrates on improving a reproducible and large scale (>1 cm^2) perovskite solar cells by using an automatic liquid injection machine in the antisolvent method. Moreover, the properties of the perovskite solar cells were compared with the devices prepared by manual liquid dropping. Liquid drops with the automatic liquid injection machine are more accurate and consistent. The characteristics can reduce tolerances from manual production. Our work increases the reproducibility and the precision for the development of large-scale perovskite solar cells. It also increases the production capacity and reduces waste generated during the production process.
$Zn^2+/Nb^5+$ co-doped $TiO_2$ (ZNTO) nanocrystalline powders were prepared by a combustion process. A pure rutile-$TiO_2$ phase of powders and sintered ceramics with a dense microstructure was achieved. Both co-dopants were homogeneously dispersed in the ceramic microstructure. The presence of oxygen vacancies was confirmed by Raman techniques. The thermally activated giant-dielectric relaxation of ZNTO ceramics was observed. Removing the outer-surface layer had a slight effect on the dielectric properties of ZNTO ceramics. The density functional theory (DFT) calculation showed that, in the energy preferable configuration, the 2Zn atoms are located near the oxygen vacancy, forming a triangle-shaped ZnVoTi defect complex. This defect cluster was close to the diamond-shape 2Nb2Ti defect complex. Thus, the electron-pinned defect-dipoles (EPDD) can be formed. The giant-dielectric relaxation process of the ZNTO ceramics might be attributed to the interfacial polarization associated with electron hopping between $Zn^2+/Zn^3+$ and $Ti^3+/Ti^4+$ ions inside the grains, rather than due to the surface barrier layer capacitor (SBLC) or EPDD effect.
High-density linear plasma devices can produce plasmas similar to that of the Tokamaks[1,2]. But, they are simple and compact than the tokamaks. The linear devices are much more cost-effective than the tokamaks for research on plasma material interactions.
In this research, a linear helicon plasma device with permanent magnets was fabricated. A half-turn helical antenna and 13.56 MHz RF were used to excite helicon wave of m = +1. The 800 G magnetic field is uniform in the vicinity of the antenna. Ar gas was used for the plasma discharges. The electron temperatures and plasma densities were obtained by using optical emission spectroscopy(OES) and Langmuir probe. When the helicon waves were excited by RF power more than 400 W, high-density plasmas of more than 10^13 cm^(-3) were obtained. The electron temperatures were in the ranges of 1 – 5 eV. The linear helicon plasma device developed in work is excellence for the studies of plasma material interaction (PMI) for development of fusion related materials. The ion fluence, similar to that of the plasma-facing wall in tokamaks, can be investigated.
Reference
1. Caughman et al., Plasma source development for fusion-relevant material testing, Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 35, 03E114 (2017)
2. R. H Goulding et al., Progress in the Development of a High Power Helicon Plasma Source for the Materials Plasma Exposure Experiment, Fusion Science and Technology, (2017)
Two types of dipole magnets are designed for the storage ring of Siam Photon Source II, the second synchrotron light source in Thailand. Magnetic field at the magnet center is 0.87 T, which bends a 3.0 GeV electron beam with the bending radius of 11.532 m and consequently the synchrotron radiation is generated. The first type of dipole magnet is a standard dipole with the magnet gap of 36 mm. The other type is designed for Infrared (IR) beamline with the larger magnet gap of 59 mm to accommodate a wide opening angle of IR radiation. The magnets are designed such that the applied operating current is the same while the turn number of magnet coils and the magnet gap are allowed to be different. Therefore, a single power supply can be used to excite all dipole magnets in the storage ring which will be connected in series. Magnet modelling and magnetic field calculation of dipole magnets are performed in Opera-3D. The magnet poles are shimmed near the edges to improve magnetic field homogeneity to be within the requirement of 2×10^(-4) within the good field region. Mechanical analysis of magnet structure is performed in SOLIDWORKS and ANSYS where the maximum deformation of 18 - 23 micrometers is found at the magnet pole and the first-mode natural frequency is higher than 200 Hz.
In our previous experiments, biological samples of naked DNA were bombarded by decelerated low energy ion beams (< 100 eV). The results found that the DNA could be damaged to induce single strand breaks (SSBs) and double strand breaks (DSBs). However, mechanisms of the low energy ion beam interaction with biological samples are unclear yet, particularly on the hot spot issue, namely what and where the most vulnerable spots of DNA are. As relevant mechanisms need deep understanding, we have planned and prepared to develop a low-energy single ion irradiation system for highly localized and does-controlled ion bombardment of DNA.
In the system, the ion beam energy is decreased by the existing deceleration lens, then the low-energy ion beam passes through µm slits and finally, low energy single ions are obtained by beam scanning from scanner plates and detected by a single ion detection device, as shown in Fig 1. Conceptual designing, calculation and simulation of the low-energy single ion system are presented in this report. The significance of developing such a system is not only in studying fundamentals of the ion-DNA interaction but also in investigation of ion irradiation fabrication and effects on microelectronics.
Keywords: Designing and simulation; Low-energy single ion; Deceleration lens; Beam scanning.
The small amounts of natural and anthropogenic radionuclides that accumulate in some human staple diets can cause harm to the health of consumers. In order to examine the level of radioactive background in staple food of Thai people, specific activity of natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides were studied and evaluated in 28 samples of organic Sungyod rice collected from Don Pradu sub-district, Pak Phayun district in Phatthalung province. The hyper-pure germanium (HPGe) detector and gamma-ray spectrometry analysis system which were set-up in advanced laboratory in Thailand Institute of Nuclear Technology (public Organization) or TINT were employed to perform some measurements and analysis for this study. It was found that the average values of specific activities of 40K, 226Ra, 232Th and 137Cs were 24.11 ± 2.01, 0.28 ± 0.07, 0.17 ± 0.06 and < 0.10 Bq/kg respectively. In addition, the average values of 40K, 226Ra and 232Th were also used to evaluate some related radiological hazard indices which are gamma-absorbed dose rate (D), radium equivalent activity (Raeq), external hazard index (Hex) and annual external effective dose rate (AEDout). Furthermore, by using the AEDout value, the excess lifetime cancer risk (ELCR(outdoor)) in this area would be also evaluated and presented. Moreover, Office of Atoms for Peace (OAP) annual report data, Thailand and global radioactivity measurement and calculations were used to compare and discussed with the present results. According to all results from this study, the organic Sungyod rice in the studied area were not only the low level of background radiation diet but also safe to consume.
Starting from June 2022, LHC will start Run-3 with proton collisions at 13.6 TeV. In this talk, highlight results from LHC Run-2 will be presented. The physics plan for Run-3 for both LHC and non-LHC experiments to be discussed. In addition, we will also discuss on the plan for high luminosity LHC which is expected to start in 2029.
We investigate the impact of a first-order chiral phase transition and critical point on hadron multiplicity ratios. We model the dynamical expansion of the hot and dense matter created in a heavy ion collision with a Bjorken hydrodynamics expansion coupled to the explicit evolution of the chiral order parameter at center-of-mass energies from 2 to 10 GeV. Hereby, the chiral dynamics is implemented using a Langevin equation including dissipation and noise. We find a strong enhancement of the entropy-per-baryon S/A at lowest energies which is created at the non-equilibrium first-order phase transition. By mapping the initial and final S/A to a hadron resonance gas, we are able to quantify the shift of hadron multiplicity ratios.
We investigate scalar field minimally coupled to gravity in the framework of holographic dark energy with apparent horizon cutoff in non flat universe. Dynamics of the model are studied by rewriting the Friedmann equation which modified by holographic effect in the form of autonomous differential equations system. In the model, we consider in pure kinetic $(V(\phi)=0)$, power law potential $(V(\phi)=V_0\phi^2)$, and exponential one $(V(\phi)=V_0e^{-\alpha \phi})$. We obtain fixed points and also analyze the nature and their stability of each fixed points. We found that de Sitter attractor solutions which corresponds to the dark energy era are obtained in the case of non minimal coupling scalar field with powerlaw and exponential potentials in flat universe.
Abstract. We study the production of charged particles and the kaonic nuclei $K^{-}p$, $K^{+}\overline{p}$ in pp collisions at $\sqrt{s_{NN}}$ = 7 TeV and $K^{-}pp$, $K^{+}\overline{pp}$ in Au + Au collisions at beam energy 130 GeV. The PACIAE model is used to calculate the charged particles, and the DCPC model is used to calculate the kaonic nuclei. Results showed that the yield of charged particles was consistent with ALICE and STAR experimental data. The yield per even of $K^{-}p$ and $K^{+}\overline{p}$ are calculated to be the order of $10^{-3}$ . The yield per even of $K^{-}pp$ was greater than the yield of $K^{+}\overline{pp}$. The kaonic nuclei $K^{-}pp$ and $K^{+}\overline{pp}$ are probably formed by $K^{+}$(or $K^{-}$) directly trapping two protons (or antiprotons). Since there are no experimental data available on this observable at present, our work may provide a guide for future experiments.
High-mass X-ray binaries (HMXBs) are systems in which a neutron star or black hole accretes material from a massive companion. They can be roughly divided into three main classes: (i) wind-fed compact objects with supergiant donors; (ii) compact objects accreting from the decretion disc of a Be star; (iii) compact objects accreting via a disc from a Roche-lobe filling companion. All HMXBs must have experienced a core-collapse supernova event during their evolution. The kick associated with this event should affect the space velocity of the system in a way that depends on the state of the binary at the time of the explosion. Here, we test whether the different evolutionary histories of HMXBs have left a detectable imprint on their peculiar velocities. Using data from Gaia Early Data Release 3 (Gaia EDR3), we first calculate the peculiar velocities ($V_p$) and associated uncertainties for 55 well-known HMXBs. The peculiar velocity distribution shows some evidence for bimodality, suggesting the existence of two distinct populations: one characterised by low velocities ($<50~\mathrm{km~s^{-1}}$), the other characterised by high velocities ($>50~\mathrm{km~s^{-1}}$). The existence of a high-velocity population is surprising for such massive systems. We use Monte Carlo simulations to set firm lower limits on $V_p$ for all of our targets, finding that at least 5 systems in our sample have $V_p>75~\mathrm{km~s^{-1}}$ at probability (p) $<2e^{-5}$.
The detection of a very extended gamma-ray emission around the Geminga and Monogem pulsars at TeV energies has set a new class of gamma-ray sources called gamma-ray halo. These objects are characterised by the presence of a rather old pulsar (~100 kyr), emitting electrons and positron that are escaping and diffusing away into the interstellar medium, producing a large scale gamma-ray emission by inverse Compton scattering. A gamma-ray halo has also been detected at GeV energy around Geminga by the Fermi-LAT. Appart from Geminga and Monogem, a few other gamma-ray halo candidates have been proposed, amongst them the TeV source 3HWC J1928+178 detected by HAWC.
In this contribution, I present the analysis of the region of 3HWC J1928+178 with 13 years of fermi-LAT data, in order to assess the presence of a gamma-ray halo around 3HWC J1928+178 at GeV energies.
We present the initial study on the membership determination of the open clusters in Cassiopeia. Proper motion and parallax of stars collected in the Gaia Early Data Release 3 are used to derive the cluster members by employing the Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm which is further improved upon using a Gaussian Mixture Model. We showed that HDBSCAN is great for determining values while GMM is great for determining the frequency and degree of a star’s membership in a cluster. We calculate the parallax and distance of the NGC 7789 cluster center to be 0.1994 ± 0.11 mas and 18637 ± 333110 pc respectively. The position of the cluster center is calculated to be α = 359֠ 16׳ 56.44״, δ = 56֠ 42׳ 38.46״ and proper motion to be µα = -1.386 ± 0.68 mas/yr and µδ = -1.052 ± 0.37 mas/yr. Our results are consistent as well with the known values from the previous studies. The stars in NGC 7789 show very little movement on proper motion and might be caused by fainter observations. The cluster is peppered with younger stars in the main phase sequence with several blue stragglers and redder stars in the turnoff region.
Circumstellar structures, such as inclination and opening angles of outflow/jet cavities, thickness and flaring angle of disk surrounding an central object, and so on, is crucial to understand formation processes of high-mass stars and their evolution more quantitatively by determining a spectral energy distribution (SED) accurately that provides us information of the spectral types and to investigate evolutionary phases of high-mass stars. The science working group for star formation researches in KaVA (KVN and VERA Array) has thus initiated a large program (LP) of multi-epoch very-long-baseline-interferometry (VLBI) monitoring studies toward high-mass protostars with multiple species of MASERs (microwave amplification by stimulation emission of radiation) using KaVA, in which each different species maser possibly traces each different significant phenomenon in jet/outflow/disk (T. Hirota, K.-T. Kim, et al.: https://radio.kasi.re.kr/kava/large_programs.php#sh3). This VLBI monitoring has enabled us to measure proper motions of the maser emissions on the sky plane and understand 3-dimensional (3-D) spatial/velocity structures and dynamics on the circumstellar structures. In this presentation, we would like to show the outline of this large program and the progress for one of follow-up observations: imaging survey and monitoring observations of the 6.7 GHz methanol masers with the East-Asian VLBI Network (EAVN). These EAVN follow-up observations have been conducted in the 2021A open-use semester for 11 target sources that were selected from KaVA-LP source list, and we succeeded imaging their spatial/velocity distributions in 4 sources, in which a source presented a structure evoking an association with a disk and accurate absolute coordinates for some sources were obtained with phase-referencing technique as well. We will also touch the on-going EAVN open-use monitoring in the 2022A semester to measure 3-D structures for the detected high-mass protostars.
Thailand is involved in the next generation of Cherenkov Telescopes, the Cherenkov Telescope Array (CTA). Amongst the main CTA key science cases is the search for dark matter (DM). With a sensitivity one order of magnitude better than current instruments, CTA will be in a unique position to discover a DM signal in the GeV and TeV energy domain, or, in the absence of it, to significantly improve the current DM limits.
In this contribution, I will introduce the principle of gamma-ray detection from the ground using Cherenkov Telescopes and in particular CTA. I will illustrate the search for a signal from dark matter annihilation using simulated data from two dwarf spheroidal galaxies, Draco and Sculptor.
Quantum gas microscope is a powerful tool for studying complex atomic many-body quantum systems in optical lattices with a high-resolution imaging. This tool is used to investigate the interplay between charges and spins, which involves many exotic phenomena. In this talk, we will discuss about the utilization of quantum gas microscope of ultracold fermions ( $^6$Li) in optical lattices for quantum simulation. Experimentally, we have a complete control over the onsite atomic interaction and the tunneling energy. Harnessing the full spin and charge detection, we directly measure spin-spin and spin-density correlations of the systems. This measurement allows us to observe the evolution of a doped Mott insulator from polaronic metal to Fermi liquid, and allows us to realize the symmetry-protected Haldane phase.
Passive vibration isolation has been extensively used to mitigate a sensitive object from unwanted motions. It is a simple configuration consisting of an isolated object, a damper, and a spring in which excess vibration is suppressed by using its harmonic oscillator. However, resonance amplification at low-frequency range is a major weakness of this system. In this work, we add an active vibration isolation on the passive system to cancel unabsorbed vibrations. Our active system consists of an acceleration sensor, a PID control system, and a piezoelectric (PZT) actuator. The PZT is used as the vibration source to generate the counteracted vibration. The PZT effect can response in a wide-frequency range up to kHz and can provide a rigid system assembly. The PZT displacement can be precisely controlled down to sub-micron range. In this work, we investigate the behaviors of the actuator and the performance of our active vibration isolator. One prospect use of our active vibration isolator will be to protect the inertial mirror in the quantum gravimeter from the surrounding vibrations.
A vapor glass cell containing neutral atoms is an important tool for developing portable quantum devices. It can be used in quantum sensors, atom chips and cryptography devices quantum-related experiments involving quantum metrology, computation and communication. In this work, we find that the absorption coefficient of rubidium atoms in our home-made vapor cell decreases as the input power of light increases. We prepare the cell by filling it with rubidium atoms in a closed system at ambient pressure. We focus on the changes of the absorption profile based on the D2-transition while we change the power of the input laser. These changes are important in determining the absorption coefficient of vapor in the glass cell, which reflects restriction of ambient pressure on the working condition of our quantum devices. The absorption profile is compared with that obtained from the commercial cell.
One of the most sensitive methods for magnetic field measurement employs quantum phenomena at atomic level. We use the Doppler-free saturated absorption spectroscopy to reveal the hyperfine levels of the rubidium atoms which obscured by the thermal broadening, we able to observe the splitting of energy levels due to an external magnetic field. Furthermore, effect of polarization of the light beam is changing the rubidium spectrum as a consequence to the optical pumping process. The measured of the energy separated subsistence an external magnetic field use toward to atomic magnetometry or analysis various theories.
Optical silica fiber demonstrated its priority in communications, which make a global village become a reality. It was predicted as a long term and irreplaceable communication technology. However, Internet of anything and big data are requiring the huge bandwidth and challenging the development speed of optical fiber communications. New All-wave fiber makes the O-L band transmission with low loss possible. Broadband optical fiber devices become the bottleneck. New designed active optical fiber with the O-L broadband emission and their 3D printing based manufacture technology are developed to supply the broadband demand and given in this talk.
General oral presentation
Solar ultraviolet radiation has both beneficial and drawback impacts on human health. Excessive exposure to ultraviolet radiation is hazardous for human. For example, it can cause skin cancer, cataracts and suppression of the immune system. On the other hand, solar ultraviolet radiation is a part of the vitamin D photosynthesis in the human skin. It is needed in the process of synthesize previtamin D in the epidermis to 25-hydroxyvitamin D via the liver and kidneys. Although Thailand is located in the equator where solar radiation is relatively high, the number of patients with vitamin D deficient is increasing. Therefore, the instantaneous amount of solar ultraviolet is needed to be known. This can be measured by using a spectrophotometer together with the vitamin D action spectral response. However, in Thailand, such ground-based instrument is very scarce. To solve this problem, this work aims to develop an empirical model for estimating hourly solar ultraviolet radiation for vitamin D synthesis under all sky condition using atmospheric parameters.
A spectrophotometer (model DMc150, Bentham Instruments) is used together with a CIE action spectral response to obtain the measured solar ultraviolet radiation for vitamin D synthesis (UVvitD) at Nakhon Pathom province, Thailand. The input of the model consists of cloud index from Himawari satellite, total ozone column from OMI/AURA satellite, aerosol ptical depth from an AERONET sunphotometer and air mass from a well-known formula. The data used in this work are in the period of 2016-2018. The result shows that UVvitD obtained from the measurement and that calculated from the model are consistent with root mean square difference (RMSD) of 17.1% and mean bias difference (MBD) of –9.2%. In further work, this model will be generalized in order to apply for all regions in Thailand.
A cavity formed from an impact of a ball on a fluid surface will begin to collapse into two volumes: one wrapping around the ball and another rising to the surface. The experiment measuring the volume of the rising cavity suggested that it is the same across different liquid densities. This research presents a mathematical model to explain the phenomenon and its correspondence with the experimental results under a certain condition. The method used in this research is a good practice for applying fluid mechanics to explain a real-life phenomenon.
General oral presentation
Drug delivery system (DDS) has been extensively interested in scientific area such as medical science, environment, industry, agriculture and food processing. In this work, nanobubble (NB) was developed as carrier in the DDS and applied in the niosome particle. The DDS had been prepared by jointing of MNB technology, mechanical technique (ball milling) and niosome particle. Drug particle consists of NB (carrier), surfactant (span 60), additive (cholesterol) and drug (melatonin). Stability and viability of the drug particle system had been defined by size and zeta potential for a moth which measured every week (total 5 times in a month). The size and zeta potential had been measured by the dynamics light scattering (Malvern Zetasizer analyzer). Melatonin encapsulation was measured by the dialysis method. The particle sizes and zeta potential of the drug particle system are an average 300 nm and -30 mV, respectively. And melatonin encapsulations are about 60%. From results can be concluded that the conditions of surfactant at span60 : cholesterol molar ratio of 1.5 : 0.5 is a proper condition. And all conditions are stability for a month as the NB carrier in drug particle system.
Keyword: Drug delivery system, Nanobubble, Niosome, Melatonin
The spread factor of liquid-stains on glass surfaces, following both perpendicular and non-perpendicular impact velocity, had been studied with a view to understanding whether surface-specific properties affect the size and shape of the stain. According to the properties of swine blood, there is a ratio of the area of change when the blood strikes the surface to the area of the blood when it contracts to equilibrium. Therefore, this research aim to impact to 2 types of surfaces, namely clean glass surface and coated with commercial non-adhesive glass surface, resulting in significant size or shape of the blood droplets. When a drop of blood impacted on glass surface, it is found that the droplet radiates and adheres to the surface. As for the water proofed coating surface, it was found that at low heights, the droplets of blood radiated and retracted into equilibrium. As the height increased, Spatter stains were formed around the drop of blood. Therefore, the rate of rebound is 53-62% . This works has demonstrated some of fundamental systematic sources of the conventional formula for interpreting elliptical stains and established some of the basic theory on which to develop the interpretation casework stains on other surfaces, in the future.
Due to their high potential for use in ceramic capacitors, high–performance giant dielectric properties (HP–GDPs), i.e., high dielectric constant (ɛʹ), low loss tangent (tan$\delta$), and the temperature stability of ɛʹ over a wide temperature range (Δɛʹ/ɛʹ$_{25}$(%)) < $\pm 15$, of acceptor/donor (A/D) codoped–$TiO_{2}$ ceramics have been widely studied since the discovery of a new $In^{3+}$/$Nb^{5+}$ codoped rutile–$TiO_{2}$. In this presentation, HP–GDPs of the $TiO_{2}$–based oxides were achieved in $Sn^{4+}/Nb^{5+}$ codoped rutile $TiO_{2}$ (SnNTO) ceramics. $SnO_{2}$ isovalent ($I^{4+}$) dopant was employed to replace the A dopants. The SnNTO samples with different $Sn^{4+}/Nb^{5+}$ concentrations (x = 0.01–0.05) were prepared using a standard solid–state reaction (SSR) method . The X–ray diffraction patterns of all the SnNTO ceramics showed only a single–phase rutile–$TiO_{2}$ (JCPS 21–1276) without any impurity phases. A highly dense microstructure of all SnNTO samples consisted of grains and grain boundaries. The average grain size slightly enlarged from 1.6 to 2.6 µm, which was caused by the diffusion of oxygen vacancies ($V_{o}^{••}$) due to the existence of multivalent $Sn^{2+}/Sn^{4+}$ ions. The dielectric properties of the SnNTO ceramics showed a high ɛʹ (~$10^{4}$), very low tan$\delta$ (<~0.05), and a low Δɛʹ/ɛʹ$_{25}$(%) < $\pm 15$ values in a wide temperature range. The origin of HP–GDPs was investigated using impedance spectroscopy (IS). The dielectric response was described by Maxwell–Wagner relaxation.
Keywords: $TiO_{2}$; Giant dielectric constant; Codopant; Grain boundary; Maxwell–Wagner relaxation
Research in van der Waals heterostructures has been rapidly progressing in the past decade, thanks to the art of sequential and deterministic placement of one two-dimensional (2D) material over another. The successful creation of heterostructures however has relied largely on expensive transfer systems that are not easily accessible to researchers. Although a few reports on low-cost systems have recently surfaced, the full functionality, portability features, and overall effectiveness of such systems are still being explored. In this work, we present an “all-in-one” low-cost transfer setup that is compact, lightweight, and portable and which can be quickly installed with a facile and do it yourself (DIY)-style anaerobic glovebox option that performs at par with commercial anaerobic systems. The “installable” glovebox option means the user has the convenience of quickly converting the working environment into an inert one when air-sensitive 2D materials are used. The lowest RH values obtained in our glovebox is <3%, and the O2 levels rapidly drop from 21% to less than 0.1% in just a few minutes of purging the chamber with inert gas. The transfer system is also equipped with a light-weight PID-controlled substrate heating option that can be easily assembled within just a few hours. We test the versatility of our low-cost system by the successful creation of hexagonal boron nitride (hBN)-encapsulated graphene and hBN-encapsulated molybdenum disulphide (MoS2) heterostructures using the hot pickup technique and graphene-hBN, MoS2-hBN, twisted MoS2, and twisted MoS2 on hBN stacks using the wetting technique, and a MoS2-hBN-graphene vertical tunneling heterostructure was formed using a combination approach. The effectiveness of the DIY glovebox is proven with the demonstration of extended stability of freshly exfoliated black phosphorous (BP) flakes, their encapsulation between thin hBN layers, and the formation of electrically contacted BP devices with a protective hBN top layer. At an overall price point of approximately 1000 $, the versatile setup presented here is expected to further contribute to the growth of research in 2D materials, in particular, for researchers initially faced with overcoming a huge entry-level threshold to work in the field of 2D materials and van der Waals heterostructures.
ALICE (A Large Ion Collider Experiment) is one of the CERN experiments along LHC that studies quark-gluon plasma, a state of matter thought to have formed shortly after the big bang. By 2021, a plan to upgrade the ALICE Inner Tracking System has been proposed and the Monolithic Active Pixel Sensor, a novel silicon sensor technology, will be employed. The ALICE PIxel DEtector is the name of the new sensor (ALPIDE). The ALPIDE sensor is planned to be investigated with a rotating telescope at the Synchrotron Light Research Institute Beam Test Facility using a 1.2 GeV electron beam. A part of this work is to study the pixel sensor telescope when the angle of the Device Under Test (DUT) plane changes. Simulation has been performed with the G4beamline software. Once the G4beamline simulation is completed, a ROOT file is produced. The beam profile and correlation plot are then analyzed. These data were used to calculate the scattering angle, which was found to be between 0.0098 and 0.0102 rad when a DUT was not rotated. Furthermore, the simulation result was compared to the theoretical calculation.
Neutron shielding materials were fabricated based on natural rubber (NR) and boron carbide (B4C) as their main components. Natural rubber, which contains a lot of hydrogen, can lower the energy of a neutron. Boron carbide, which contains a lot of boron, may absorb neutrons. The shielding materials were created with boron carbide concentrations of 0, 20, 40, and 60 parts per hundred rubber (phr) and thicknesses of 2, 5, 10, and 15 mm. The manufactured materials will be examined for neutron absorption efficiency using an Am/Be neutron source at the Radiation Measurement Laboratory at the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University. In this example, the findings will be compared to those of a Monte Carlo N-Particle (MCNP) transport code and silicone rubber sold in Japan by Atom Shield Co., Ltd.
Galactic-scale outflows driven by active galactic nuclei (AGNs) have been invoked to explain the quenching of star formation in massive galaxies. Large statistical outflow samples are required to study to fully understand their impact on galaxy evolution. The most traditional technique to distinguish the outflowing gas from non-outflowing gas is to detect the blueshifted-wings in the absorption and/or emission-line profiles as they represent the outflowing motion of the gas. However, this technique requires spectra with high signal-to-noise (S/N) ratio to decompose outflowing components. Over past decades, many researchers have developed a new technique to obtain a significant number of galaxies with large-scale outflow by reconstructing images of [O III]$\lambda\lambda4949, 5007$ emission using narrowband and/or broadband images. Nevertheless, the gas kinematics of the outflows selected from this technique are less studied. To answer this question, we compare the selection efficiency of the galactic-scale outflows from broadband images and spectroscopy. We apply both of the outflow selection techniques to 165 local galaxies ($z\sim0.1$) observed by the Mapping Nearby Galaxies at APO (MaNGA) survey, the latest integral-field spectroscopic survey of the Sloan Digital Sky Survey (SDSS). Fourty-seven ($\sim28\%$) galaxies are classified as AGNs based on line diagnostic diagrams and multi-wavelength observations. We construct [O III] images using the SDSS broadband images together with a continuum subtraction of the galactic continuum. We find that the area of [O III] emission-line regions are positively correlated with the outflow velocities, as traced by the 98\% extent of Na ID $\lambda\lambda$5890,5896 absorption lines with a power-law slope of 0.64$\pm$0.16. We discuss the selection efficiency and applications of the broadband images to study the AGN feedback with large statistical samples.
We use numerical simulations to study the evolution of merging galaxies. This study focuses on the AGN-driven feedback mechanism which could be responsible for outflow gas on kpc scales observed in Seyfert galaxies. The galaxy's initial conditions were created to mimic observational properties of a galaxy NGC 5252. The object is one of the interesting seyfert galaxies, showing an extended [OIII] emission out to ~10 kpc scales and appears to contain an off-nucleus ultraluminous X-ray (ULX) source, CXO J133815.6+043255, with optical spectral properties similar to Low-Luminosity AGNs (LLAGNs). The high angular resolution very long-baseline interferometry (VLBI) observations have also showed that it is a promising candidate of dual radio-emitting AGN system. Furthermore, the off-nucleus ULX component in the NGC 5252 is believed to be a stripped remnant of a merging dwarf. To study the formation and evolution of such a system, the supermassive black hole (SMBH) accretion physics module is employed in the smoothed-particle hydrodynamics (SPH) simulations of merging galaxies, using GIZMO code. We will report on the progress of our on-going study which will be focusing on possible configurations and properties of the merging galaxies, the evolutions of the merging pair and AGN feedback that results in the observed properties of the system.
Anisotropic flow in Au + Au collision at 1 A GeV using a quantum molecular dynamics model was concentrated. The direct flow of proton ($v_{1}$) as a function of rapidity ($y_{0}$) at intermediate energy around 1 A GeV and impact parameter from 0.25 to 0.45 fm with the nuclear equation of state (soft and hard equation of state) were computed and compared with FOPI experiment. The results showed that the direct flow of proton as a function of the rapidity with a soft equation of state was consistent with the FOPI data. The behavior of the nuclear equation of state at high temperature and high density could be explained by the calculation result of the proton flow from Au + Au collision at intermediate energy.
The Schamel-Korteweg-de Vries (SKdV) equation is the equation which described weakly ion-acoustic wave in cold plasmas. The soliton solution to the Schamel-Korteweg-de Vries equation can be determined by the shooting method. The spectral method is applied to study the time evolution of this solution. This can experimentally confirm that the solution is stable.
The Fourier transform spectrograph (FTS) is an important tool that has been applied in many fields of research. In astronomical observation, the FTS has been used for analyzing stellar objects. Most of FTS that hav been designed and used with large telescope are based-on free space design to maximize flux throughput at the detector. However, the limited space at a focal plane of a large telescope may lead to complex design of the FTS if not impossible. To overcome the space limitation, a fiber-fed design of FTS has gained more interest. The used of fiber to feed the star incoming flux from the telescope to the spectrograph makes comfortable for an optical alignment of the system. Nevertheless, the main challenge of the fiber-fed FTS is a low flux throughput due to a single point field of view and a transmission loss in the optical fiber. In this work, we report the development of the laboratory prototype of a fiber-fed FTS specifically designed for the Thai National Telescope (TNT). Off-the-shelf optical components have been mainly used in the implementation. To improve the signal-to-noise ratio of a low flux signal, a balanced detection scheme has been investigated. The simultaneous detection of scientific and metrology interferograms for correction of the phase distortion of the interferogram has been implemented. The phase distortion in the measured interferogram was corrected by using peak-valley positions of the metrology interferogram. The instrument line shape, corresponding with the spectral resolving power of the system was measured to be higher than 19,000. Furthermore, the scan range of the FTS was maximized to obtain the maximum spectral resolution of the implemented system. The achieved maximum optical path difference is currently about 30 mm.
For fruit and flower transportation, ethylene gas is necessary to be detected. Various techniques are innovated, and the hollow core optical fiber is one of them. Its structure is suitable for flowing gas. So, it is used as a gas cell. This work proposed the nested hollow-core anti-resonant fiber made of Polyethylene Terephthalate (PET). Our structure is optimized to get the lowest loss at a wavelength of 3.2 um, which is related to the ethylene absorption band in the Mid-IR. The confinement loss is predicted from the numerical simulation in COMSOL. After trying to vary parameters such as core diameter and cladding tube thickness, we obtain a loss lower than 2 dB/m at the core diameter and cladding tube thickness of 108 um, and 2 um, respectively.
General oral presentation
Newton’s cooling law provides a linear differential equation governing the rate of heat loss of a heated body using the temperature difference of the body with the environment. However, the prediction of Newton’s cooling law still did not fit with the data under the laboratory framework. Previous works have modified Newton's cooling law by incorporating fractional derivatives as a basis of their models, and in particular cases of convective fluid, higher correlations with the experimental data can be observed. In this study, to model the empirical value obtained from the experiment, the conventional model is enhanced by appending a new parameter as the exponent of time in the differential equation. The comparison is shown between the conventional Newton’s cooling law and the modified model, along with its adjusted R-Squared value from the regression of the experimental data, which results in a significant enhancement from the conventional model. In a numerical relationship between the two parameters, correlation of this newly proposed model is found with an established model of Newton’s cooling law using Caputo type fractional derivative, thereby providing some support to the theoretical basis of the model. Moreover, the performance of this modified model is to a certain degree higher than the fractional derivative model.
We perform a Monte Carlo simulation to study the propagation of uncertainty in Euler rotational kinematic equation. The rate gyro data from an IMU sensor (mpu6050) are inserted into the Euler rotational kinematic differential equation to calculate the sensor orientation, which is specified by its Euler angles. The uncertainty of sensor orientation is determined by simulating the variation of rate gyro input due to its uncertainty obtained from the calibration process. We find that the uncertainties of the Euler angles grow with time. Their values are proportional to the square root of time elapse. We find also that the rate of change of uncertainties are linearly proportional to the sampling time and the square of uncertainties of rate gyro data. These results interestingly resemble the behavior of a Wiener process, with the step size of random walk depends on the time step. We can use these results as a criterion to choose a suitable IMU due to the characteristic of the integrated rate gyro sensor, especially in the application like the vehicle tracking or posture warning for elderly/disable people, where the precise sensor orientation is needed for a long period of operation.
In this report we present a machine vision algorithm for pointer gauge reading based on coordinates transformation. Since a pointer gauge is a polar representation of a linear scale, it is possible to transform its polar reading to the original linear counterpart. Once the picture of a pointer gauge is captured digitally, we can assign the polar positions to each pixel of the image. Those polar coordinates can be plotted on a rectangular frame to form a transformed image. The scale lines and the pointer are transformed to point vertically (or horizontally). Locations of the scale lines and pointer can be obtained from their pixel histograms maxima. An advantage of our algorithm is that we can avoid the complication of the conventional algorithm, e.g., Hough transformation, to find the orientation of pointer and scale lines. We have tested the algorithm with the ideal and real image of pointer gauges. In the latter case, even though there are some noises on the transformed image, the locations of pointer and scale lines can still be easily found from their histogram maxima. The other advantage of the algorithm is that, due to the polar structure of the gauge, the algorithm does not strongly depend on the orientation of the gauge with respect to the camera. We have tested the case where the camera is not pointed perfectly perpendicular to the gauge panel. Our algorithm still works quite well. Again, we can avoid the difficulty of the conventional algorithm that can strongly depend on the configuration of the camera and the pointer gauge.
During the fall of a Mahogany seed, its wing-like structure is used to create rotational motion to propel itself further. The following research is concerned with the moment of inertia of the seed, which is the basis for analysing the rotational dynamics of the body. The formula used for calculating the moment of inertia was derived based on the approximated geometry of the seed. The inhomogeneity in mass distribution was also considered, and three experiment setups were performed to measure the moment of inertia. The results from these experiments are in an acceptable range of variations. However, the comparison between the formula and the results of the experiments suggests that the empirical factor of 2 must be introduced to the formula. The source of discrepancy is due to the resistance in the system. The obtained semi-empirical formula can be applied in the further study of the Mahogany seed’s motion. Moreover, the techniques used in this research could be applied as good practice in high school and undergraduate physics laboratories.
Assessment of annual effective dose due to inhalation and ingestion of radon from 43 groundwater samples at Kantharawichai District, Maha Sarakham Province by using Radon Gas Monitor ATMOS 12 DPX. The results were as follows: 1. radon concentrations in groundwater were ranged from 1.04 – 21.87 Bq/L with the mean value of 8.27 Bq/L., 2. The annual effective dose due to inhalation from groundwater (Dinh) was ranged from 2.61 – 54.68 µSv/y with the mean value of 20.66 µSv/y. The annual effective dose due to ingestion from groundwater (Ding) was ranged from 0.19 – 3.94 µSv/y with the mean value of 1.49 µSv/y., 3. The annual effective dose on organs, namely the dose on lungs (Dinh-lung) was ranged from 6.26 – 131.24 µSv/y with the mean value of 49.59 µSv/y, and the dose on stomach (Ding-stomach) is 0.45 – 9.45 µSv. /y and has a mean of 3.57 µSv/y., and 4. The mean of excess lifetime cancer risk (ELCR x 10-4) in males was 0.88 and in females, it was 0.96. The results will be compared with the action levels of various organizations, including: The maximum allowable radon concentration in water is 11.1 Bq/L, according to United States Environmental Protection Agency, and The allowable annual effective dose due to inhalation and ingestion of radon from groundwater (D) is 100 µSv/y, according to the World Health Organization. The result of analysis by comparing the data of research with the action levels of various organizations can indicate the safety of inhalation and ingestion of groundwater radon in the research area.
Green and clean diets are on focus for consumers with healthy and safety concerns. Good source of safe and clean vegetables and fruits are vital. Vegetables and fruits are often found on market shelves in below standard of good agricultural practices. Pesticides and other chemical residues are found in those fruits and vegetables which may connect to many late complication issues in health. Various methods are utilized as common wisdom to fight the problem. Some methods are more practical and handier. This contribution has studied properties of tap water after activation by a commercial fruit and vegetable purifier. Chlorine, which is present in tap water, is bound with hydroxyl radical from electrohydrolysis by an apparatus to form hypochlorous acid. The activated water is found to peak at 291 nm in its absorbance with a UV-Vis spectrophotometer. Properties of water were studied under various experimental settings such as comparing with activation of de-ionized water, as a function of (i) operating time, (ii) storing time of input tap-water, (iii) storage time of activated water and (iv) water volume. Concentration of hypochlorous acid is calibrated against commercial ready-to-use acid.
The surface water wave can be easily seen in everyday life. Extracting crucial wave characteristics is however challenging since the wave propagation phenomena occurs so rapidly to measure its characters. Free surface synthetic schlieren (FS-SS) offers a great visualization technique of surface water disturbance using invert gradient algorithm of background patterns. In this study, a ring surface water wave generated by falling water droplet was investigated using MATLAB PIVlab and PIVmat toolboxes to reconstruct 3D surface of the ring wave. Wave properties including wave packet profile and phase speed were readily extracted from the technique. The wave pattern could salon be further used in determining surface tension and wave damping coefficient.
An invisible cloak is an appliance that is frequently mentioned in many pieces of non-scientific literature as an attention-grabbing component. It can cause any desired object to disappear while the observer will still see its surroundings, i.e., the object under its effect becomes translucent. A similar effect can be demonstrated in laboratories by using optical instruments such as a lenticular lens. The mechanism in which the lenticular lens uses to hide the object was theoretically and experimentally investigated in this research through the knowledge of geometrical optics, especially the ray-tracing analysis. A discussion on the aspects of wave optics was also conducted to obtain a comprehensive understanding of the phenomenon. To verify the theory, a computational simulation was created based on the proposed theory. The simulation result was compared with results from the experiment under various conditions such as the distance from the object to the lenticular lens. The method used in this study can be applied in the classroom to enhance students’ understanding of the geometrical optics and wave phenomenon.
Hair cells are the sensory receptors of the auditory and vestibular systems. A bundle of cilia situated atop each hair cell, termed the hair-cell bundle, is deflected upon an impinging of a mechanical force. This subsequently modulates the open probability of mechanically gated ion channels. Owing to the asymmetry in the geometry of the hair-cell bundle, individual hair cells are polarized and display the maximal response to a force applied in a certain direction. The auditory organs of most vertebrates comprise primarily hair cells with identical polarity, whereas hair cells of the vestibular system are organized in two opposite polarities. To understand the advantages of the bi-polarity arrangement of hair cells, we employ the theoretical framework of active nonlinear oscillators to investigate the dynamics of a system of two coupled hair-cell bundles with opposite polarity. Each hair-cell bundle is described by a nonlinear oscillator poised near a supercritical or subcritical Hopf bifurcation. Our results from numerical simulations reveal that a system of coupled hair-cell bundles with opposite polarity can undergo a limit-cycle oscillation, but with a significantly altered value of the critical control parameter. Predictions from the model further demonstrate that reversing the polarity of a hair-cell bundle can enhance the response of the system to a bi-directional constant force, as well as a periodic force, with respect to the displacement of a system of two identical hair-cell bundles.
The ant species Oecophylla smaragdina, commonly known as the weaver ant, is native to tropical Asia and Africa. Ants are known for highly-organized, co-operative behavior and weaver ants are particularly adept at working together, in numbers, to accomplish large-scale tasks. Considered an example of a coherent many-body system, weaver ants have been studied by researchers in various fields. As a first step towards understanding weaver ant coordinated motion, we want to find the algorithm that a single ant employs for its own navigation. Having previously tracked the motion of individual ants within a small, bounded arena, we here present a simple theoretical model that can describe this motion. We show that their navigation can be adequately modeled as Brownian motion: the ant velocity changes by random impulses drawn independently from a robust probability distribution. Using establish Brownian motion theory, we show that the ant’s tendency to remain near boundaries can be explained as a result of pure chance: having been stopped at the boundary, random motion is unlikely to bring the ant back to the arena interior. All qualitative aspects of ant motion are captured by a model with few parameters and without any assumption that an ant has preferences for position or velocity.
In this article, we investigate the network structure of stocks in the Thai stock market from 2008 to 2020, applying the correlation distance as weights and the average of correlations as a criterion for deciding whether two stocks are connected. We can access and filter strongly correlated and weakly correlated stocks in a financial network using different average correlation thresholds ($\mu-5\sigma$, $\mu-3\sigma$, $\mu$, $\mu+3\sigma$, $\mu+5\sigma$). The results indicate that during high volatility situations, such as the global financial crisis in 2008 and the COVID pandemic in early 2020, the network's characteristic path length decreases, whereas the clustering coefficient increases. These findings suggest that the network structure has shrunk in size, and stocks are now tightly linked, resulting in a similar trend of price and return behaviors observed in many stocks during financial crises. Also, the minimal level of network entropy implies that the complexity decreases, and each node of the network has lost its ability to perform independently across stock sectors. Furthermore, we discover that the banking and utility sectors have the highest probability of being a hub of the network clusters. This research can contribute to the explanation of stock clustering in terms of entropy and network topology.
Keywords: stock network measurement, network entropy, financial market, econophysics
Radiative cooling is a passive cooling process that requires no additional input of energy which can be used as a cooling process in various fields. Though many radiative cooling materials have been conducted to improve efficiency in temperature reduction during the past few years, the scalability and the applicability are equally important. With high efficiency and low scalability, applications of the radiative cooling film would be severely limited. In this research, doctor blade coating technique was explored as a high scalability process, and the resulting thickness of the obtained film remained within the desirable range of 11-13 um, which correspond to the atmospheric window. The field experiment performed on the rooftop confirmed that the doctor blade-film can reduce the temperature by 3-4 °C below the ambient, comparable to the performance of the commercial radiative cooling film and the lab-based spin coating film. Moreover, by forming the patterns with the sizes between 8-13 um on the film, additional resonance in the atmospheric window range could be induced, enhancing radiative cooling efficiency.
General oral presentation
Nowadays, there is much software used for both education and astronomy research. For photometry, license software and high performance of computer’s operating system are required, which are a fund limitation for some schools in Thailand. Thus, in this article, we develop and present the Demonstration Photometry Scripts for Astrophysics Teaching (DPSAT version 1.0). The program is designed to work on cloud computing services via internet browsers to avoid the hardware and operation requirement pain points. The DPSAT is programming on flexible, low-cost, on-trend language, Python, and Jupyter Notebook online editor. In advance, our new code supports the home-use image or video file format, i.e., jpg, png, or mp4. Thus it will be more accessible for teachers and students who do not have the standard astronomical instruments. The DPSAT measures the stellar light intensity from the time-series still-images or video files from a smartphone or another digital device. The code can extract video files into sequenced still images, then transform the RGB color space images into greyscale. The light intensity signal of selected pixels is counted with a simple aperture method in time series. It shows the results, for example, the mean signal, standard variation, measured signal as light intensity versus time, and image of light sources. This will be fruitful for low-cost and easily accessible for teaching astrophysics subjects.
The traditional method of dial gauge calibration is time consuming and a measurement result is depending highly on human errors. To overcome this problem, an automatic measuring system based on machine vision has been proposed. This paper presents an application of machine learning based on Open CV for automatic digital dial gauge calibration. The k-Nearest Neighbors algorithm is applied for characters recognition of the dial gauge panel. The dial gauge tester developed in this study has a calibration and measurement capability (CMC) of approximately 0.0012mm. Even though the image of a dial gauge reading is slightly disturbed due to reflected light, the algorithm indicates efficient characters recognition of dial gauge reading. In this study, a calibration result from the developed method and traditional method were compared using a commercial digital dial gauge with a measuring range of 10 mm. The result shows good agreement with a comparable measurement uncertainty, approximately 0.008 mm. The automatic calibration system, however, has many great advantages over the traditional method as the algorithm can eliminate most human errors and also can reduce measurement time by 70%.
Raman spectroscopy is a spectroscopic technique that is used to analyze the chemical constituents or structure of molecules and can be applied to solid, liquid, and gas materials. This technique has been widely used in various fields such as analysis of medicine constituents in a pharmaceutical application, narcotic classification, examination of explosive substances for forensic medicine, and usage in quality control of semiconductor and microelectronics process industry. The Raman technique relies upon the inelastic scattering of photons, which is called Raman scattering. The Raman signal, which is either lower or higher energy than the incident photon due to inelastic scattering, is emitted when excited sample molecules at a virtual energy state transiting to the ground state in a short time.
Commercially, almost Raman spectrometers are constructed with many optical and electrical parts for fluorescence noise and background reduction and Raman signal enhancement. Consequently, almost commercial Raman spectrometer systems were neither compact nor carriable for field usage purposes. Therefore, in this study, we propose an approach to develop a compact Raman spectrometer that can be used in the field. Our system is only composed of necessary components such as a laser source, lens, and compact spectrometer. These components are designed to be set up in a compact area. Then, the raw Raman signal from a compact optical system with large noise and background signal is filtered by using a polynomial fitting-based Vancouver algorithm. The Vancouver algorithm is chosen because it is more accurate and faster than other methods in noise and background removal. According to the experiments, we found that our approach can give distinguish Raman peaks of the paracetamol sample, which is very close to the signal from the commercial system. Therefore, our designed system approach will be applied to make the Raman spectrometer for field usage in near future.
Proton computed tomography (pCT) is a novel radiography technology that is used for treatment planning in proton therapy with better benefit of higher position accuracy than the conventional radiography. This work focused on the design and construction of a synchronizing system, the so-called the pCT trigger controller as a key communication part in the pCT prototype. This controller was designed using the MEGA2560 pro mini as a microcontroller unit (MCU). The MCU connected to the SAMKOON SK-070FE HMI touchscreen using Universal Asynchronous Receiver/Transmitter (UART) to create a graphical user interface (GUI) based on Modbus protocol via the C language program. The controller was tested at King Chulalongkorn Memorial Hospital (KCMH) on August 2021 and March 2022. It was found that the controller can send the programmed signals to control the rotational stage, ALPIDE sensors, and TSS interface box of the proton beam in a desired sequence. Where the ALPIDE sensor interfaced with EUDAQ2 software to record the hit map of protons on ALPIDE’s active area.
The autocollimator is a non-contact angle measuring instrument using the geometric light reflection principle. The instrument can be used in scientific research and industrial applications with high resolution. In this work, we propose an application of the autocollimator for surface profile measurement. We use an autocollimator to directly measure the tangent profile of a surface. The results can be interpreted as the first partial derivative of the surface along 2 reference axes. The higher derivatives can then be calculated. For second-order bi-quadratic approximation, the second derivatives are used to estimate the bending and twisting of a local surface. We compare our results with that of the industrial, high-resolution interferogram. The results agree well with the RMSE ranging from 2 nm to 10 nm.
Conventional laser triangulations are designed to measure the depth or height on a dull or rough surface. This can be done by projecting a light perpendicularly to the surface and capturing the spot of the diffuse reflection which is scattered from the surface. However, for a shiny or smooth surface, the specular reflection dominates, and it is difficult to detect diffuse reflection. We may modify the system setting to capture the specular reflection, with the cost of losing the diffuse reflection information. In this article, we proposed a design of dual diffuse and specular reflection mode of laser triangulation. The advantage is that there is no need to repeat alignment and calibration processes when we change the measuring mode, so we can easily select the measuring mode that is suitable for each surface. We have described the system setting, the calibration results, and the uncertainty evaluations for the laboratory-scale experimental demonstration, where we can achieve the resolution of micrometer for both measuring modes.
OctoPrint is a powerful open source 3D printer software what user can control and monitor printing jobs with its own online server that suitable for remote and isolated work. The Raspberry pi 3 B+ is hardware for installing Octopi that including Raspbian operating system and OctoPrint software. An USB webcam was connected for live viewing of printing processes and the ESP32 microcontroller with filament runout sensor was communicated to Raspberry pi 3 B+ for notify user when filament was runout or back to work resume through LINE mobile application. The Google Calendar and LINE mobile application were used for jobs booking of multiple users that will notify before and after finish printing for each user. The Power relay circuit was used for shut down the Raspberry pi 3 B+ when complete printing to save energy and electricity.
Modelling is a power tool in a development of an engineering system. In this study, a solar vapour compression refrigeration system was modelled by two machine learning approaches, namely ARX and ANN and the performance of these two approaches were compared. The solar refrigeration system is composed mainly of a vapour compression unit, two 300W-solar modules, two 12V-batteries with the capacity of 200 Ah (each) and a charge controller. Ten experiments were carried out. Water contained in a bottle was used as cooling loads. The load of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 liters were employed in the experiments. Data obtained from the experiments with the loads of 10, 30, 50, 70 and 100 liters of water were used to construct the model and experiments with the loads of 20, 40, 60, 80 and 90 liters of water were employed to test the performance of the model. The difference of the load temperature from the experiments and those predicted by the models, in terms of the percentage of root mean square difference relative to a mean measured values (RMSD) was used as an indicator of the performance of the models. It was found that the RMSD of ARX model and ANN model were 4.3% and 5.4%, respectively. We conclude that ARX approach performs batter than ANN approach for this system.
The reactive oxygen nitrogen species (RONS) from plasma activation is intensively used in agriculture, particularly in the regulation of seeds germination and plants growth. It shows a promising effect on increasing the germination rate and promoting the growth of plants. This research employs plasma activated water (PAW) in cultivation of green algae (Chlorella spp.). The objective of this research was to introduce a comparison between the use of different fluids for cultivation of green microalgae. The used fluids were fertilized water, simulated-fertilized water, tap water, tap water treated with activated plasma for 2.5, 5.0 and 7.5 minutes. Samples of green microalgae were cultivated in these waters for 7 days. A comparative investigation was conducted and reported. It was found that concentration of the reactive oxygen nitrogen species increased with the treatment time. According to the growth of green algae, the plasma activated water provided a better result than any other until day 2. This indicates an effect of RONS on promoting the growth of green algae. Upon completion of the test, the fertilized water showed the highest growth. This finding could be distributed to a rapid reduction of the reactive oxygen nitrogen species. However, a well-controlled plasma activation would make PAW possible for industrial uses in the future.
Keywords: plasma activated water (PAW), green microalgae, Chlorella spp., growth rate and plasma arc discharge.
Tomato, mango, banana and durian are climacteric fruits characterized as having high respiration rate during the ripening. Generation of ethylene is actively involved in metabolic activities leading to the ripening. Inhibition of the ethylene generation is therefore able to delay the ripening. Typically, the ethylene generation is dependent on temperature, oxygen level and fruit injury which includes mechanical damage, diseases, and insect infestation. These factors stimulate the generation of ethylene. To overcome this issue, low CO2, low temperature and the use of ethylene absorbent are conventionally required. However, in the current work, a technique using dielectric barrier discharge (DBD) plasma was proposed. DBD plasma could not only eliminate ethylene but also moisture in the package in a short period. In this work, a comparative study was done on storing cultivated banana, papaya and mango in different ways of storage: non packed, packed in a paper box, packed in a paper box treated with 5-minute plasma, packed in a paper box sealed with plastic wrap, packed in a paper box sealed with plastic wrap and treated with 5-minute plasma and packed in a paper box sealed with plastic wrap and treated with 10-minute plasma. It was found that the cultivated banana samples ripened in sequence, when packed in (1) the paper box sealed with plastic wrap, (2) the paper box, (3) non-packed, (4) the 5-minute plasma box, (5) the paper box sealed with plastic wrap and treated with 5-minute plasma (6) the paper box sealed with plastic wrap and treated with 10-minute plasma. This suggests that C2H4 was successfully removed by a DBD plasma reactor.
In all sports involving a ball, spin is heavily utilized to alter the ball's course. A spinning ball has more kinetic energy of the same ball traveling with the same translational velocity. The additional energy comes from the rotation of the ball. This extra hidden energy can affect the trajectory of the ball as the ball interact with the floor or even with the air. Dimples are placed on the golf balls to increase the friction with the air making the spin effects on the trajectory more pronounced. Good pitchers can curve the trajectory of a baseball by throwing the ball with a lot of spin. In this work, we use simple tools to study of how spin affect the bouncing trajectory of a ball. The height of the ball when thrown with different spins, such as back spin, top spin, and no spin, will be investigated in this experiment. The heights of the bouncing balls were collected using a high-speed phone camera and evaluated with a video analysis software. The height ratio of basketball with spin-launching is higher than without. The height ratio of back spin launches is higher than that of top spin launches. The bouncing angle will affect back spin, whereas the angular velocity will affect top spin. By launching the basketball with spin, the height ratio of the bouncing ball can be enhanced. The changes in the bouncing angles and trajectories due to spin will also be discussed. We believe that a simple setup used in this experimental study can be applied to study the behaviors of many other movement of objects.
Global spectral solar irradiance is of importance for various solar energy applications such as photovoltaic systems and selective surfaces of flat plate solar collectors. In this study, a model for estimating global spectral solar irradiance under all-sky conditions for Nakhon Pathom station (13.82˚N, 100.04˚E) Thailand was developed. The model expresses the global spectral solar irradiance under all-sky conditions as a multiplication of two functions. The first function is a global spectral solar irradiance under clear sky condition and the second function is an expression of a cloud modification factor. This factor is a function of satellite-derived cloud index. To obtain the first and the second functions, global spectral solar irradiance was measured at Nakhon Pathom station in Thailand for the year 2017-2019 using a spectroradiometer (EKO, model MS-710). Ancillary data such as aerosol optical depth and precipitable water were obtained from an AERONET sunphotometer installed at the same station. The validation of the model was carried out using an independent data set from the same station for the year 2020. It was found that the global spectral solar irradiance from the measurement and that calculated from the model were in reasonable agreement, with the discrepancy in terms of root mean square difference (RMSD) and mean bias difference (MBD) of 12.39% and -0.64%, respectively.
In the past few years, there were accidents that caused people to die from hydrogen sulfide gas. This is due to the lack of warning system and appropriate measuring equipment. General commercial hydrogen sulfide detectors are not suitable to use in the risk area as users have to take them into the area which could be dangerous if the gas concentration exceeds the limit. Therefore, the purpose of this research was to develop an innovation that can remotely detect hydrogen sulfide concentration, display detected results to the users via smartphones. It also alerts when the concentration is in hazards level. This innovation was designed to be compact and easy to use. It applies a microcontroller (Arduino) combine with a MQ-136 gas sensor to measure hydrogen sulfide concentration. Measured results are real-time analyzed to determine the hazards of the gas and user recommendations. All measured and analyzed results are displayed both onsite and online. An OLED display is used to show the results for onsite. A buzzer is also used to warn the users when the gas concentration is at a dangerous level. For online display, the users can remotely monitor all results via their mobile devices (smartphones or tablets). Thingspeak.com was used as platform to collect results. A mobile application was created using MIT App inverter to retrieve the results and display them on mobile devices. The innovation prototype was tested to measure hydrogen sulfide gas in the range of 0-200 ppm. The operation of the prototype is in accordance with all requirements. These results show that the prototype can be used for real-time remote hydrogen sulfide measurement.
Keywords: Hydrogen sulfide detection, microcontroller and sensor, remote measurement
Excellent giant dielectric properties (ExGDPs) of dielectric oxides have been widely investigated due to their significant potential for many applications, especially for ceramic capacitors. However, low loss tangent (tan$\delta$) and temperature coefficient ($\Delta$$\varepsilon$$^,$(T)/$\varepsilon$$^,$$_\text{RT}$) are difficult to achieve. In this presentation, we show systematic strategies for moving beyond conventional material problems in order to obtain a material that meets the practical requirements. The electron-pinned defect-dipole (EPDD) and internal/surface barrier layer capacitor (IBLC/SBLC) effects in TiO$_\text{2}$-based materials are proposed for obtaining the ExGDPs with high ultra-low tan$\delta$ (<0.01) and very high dielectric permittivity (>104) with temperature coefficient less than $\pm$ 15% over the temperature range of -55 – 200 $^{\circ}$C. The relevant electric polarization mechanisms in the TiO$_\text{2}$2-based materials are described.
An abruptness of InGaAs/InP heterointerfaces in the superlattice (SL) structure grown by metal-organic vapor-phase epitaxy has been improved by optimizing a gas-purging period of tertiary-butyl phosphine (TBP) onto the InGaAs terminated surface, and tertiary-butyl arsenide (TBA) onto the InP terminated surface. The non-abrupt heterointerface is a result of intermixing layer formation caused by two main effects: (1) carry-over and (2) diffusion of group-V atoms. The sample composes of 20 periods of InGaAs (2 nm)/InP (10 nm) epitaxially grown on the InP substrate in [001] direction. The In composition in InGaAs was adjusted to be 53% which is a lattice match to InP. The layer structure was characterized by high-resolution X-ray diffraction. Crystal quality and relaxation were analyzed from the reciprocal space mapping result recorded around diffraction from the InP (-2-24) asymmetric plane. Lattice mismatch and layer thickness were examined by the 2θ-ω results around the InP (004) symmetric plane. In this work, we proposed a model in order to estimate the thickness of intermixing layers by using the Fourier transform of a periodic trapezoid-shape scattering function to fit an intensity of high-order satellite diffraction peaks. Since InGaAs has a lower energy gap than InP, the InGaAs layer could be considered as a quantum well (QW) inserted between the InP barriers. Hence, we also analyzed the QW shape of SL structures via the ground-state transition energy characterized by room-temperature photoluminescence. Our results show that purging the InGaAs terminated surface with TBP for 2-4 s could effectively remove residual As atoms and reduce As carry-over into the next-grown InP. By purging the InP terminated surface with TBA, even though an effect of P carry-over is reduced, the structure becomes more suffered from diffusion of As atoms into the beneath InP layer.
EFFECT OF ANNEALING CONDITIONS ON VO2 THIN FILMS PREPARED BY SOL-GEL METHOD
Sub.Lt.Pongsatorn Panburana, Salinporn Kittiwatanakul
Abstract
Vanadium Dioxide has attracted considerable attention because of the metal-semiconductor phase transition at 68oC. This reversible transition changes crystal structure from monoclinic to rutile resulting in tremendously change of transmittance and reflectance of Infrared wavelength and electrical resistance making VO2 thin film potential candidate for energy-saving smart windows (automatically block heat).
However, its preparation is very challenging due to the multivalence of Vanadium element. In this study, we explored different annealing conditions for thin films synthesized by sol-gel method which has advantage over other methods such as lower cost, simpler process and ability to make large scale thin film.
In the experiment, we used vanadium (V) triisopropoxy oxide (VO(OC3H7)3) as precursor. The annealing conditioned explored are annealing temperature and annealing time of thin films in low pressured Argon rich atmosphere. The spin-coated films were annealed at 350-530 ºC for 30 minutes, while another set were annealed at 450 ºC for 30, 60, 90, and 120 minutes. Then the films were characterized with Raman spectroscopy and temperature dependent resistance measurement. The results show that the longer the annealing time and the higher the temperature are better for film formation —closer to VO2 (higher V:O ratio).
In addition, the effect of various substrate types was also explored, another set of thin films were coated on c-plane sapphire (c-Al2O3) and Soda lime glass (SiO2) to compare the effect. Then the films were characterized with Raman spectroscopy and X-Ray Diffraction. The result showed that sapphire substrate yielded better film formation.
Keywords: VO2 thin film;; Argon atmosphere; electrical resistance property; annealing temperature ; XRD; Raman spectroscopy spectroscopy
Nowadays, the most anxious problem is global warming which caused by an emission of CO2. To solve this problem, this research proposes the use of high porosity, stability, and simple synthesized material, metal-organic framework (MOFs). The aim of this work are synthesis and chemical modification of MOFs, UiO-66(Zr) that prepared from plastic waste, polyethylene terephthalate (PET). Hydrothermal technique was carried out for depolymerization of PET to produce orgainic ligand, BDC, then modulated synthesis technique for UiO-66(Zr). FTIR showed O=C−O in carboxylate group in BDC at 1675 cm−1and a smaller band at 1508 cm−1 presented C=C vibration of a benzene ring. These are summarized that is the success of synthesizing BDC from PET. However, to confirm a chemical structure NMR will be reported. The further step are using hydrothermal and ultrasonication techniques to synthesize combination two of UIO-66 with NH2, NH2-GO, and NH2-GMA functional groups and their characterization. After that, investigation of their CO2 absorption efficiency will be examined.
The bulk $Cr_2O_3$ (Chromia) is one of the candidates for voltage-controlled spintronics which is a key element for magnetoelectric random access memory (MERAM) due to its antiferromagnetic and magnetoelectric effects in high temperature. However, engineering applications MERAM require thin films to reduce the voltage required and the chromia films might have different physical and magnetic properties from bulk ones because of film surface effects. Therefore, Density Functional Theory (DFT) study and the Atomistic spin model were used to investigate the effects of bulk and film chromia in this work. The results from DFT calculations showed that the Density of states (DOS) and Band structures of chromia films might be induced by defects and surface interaction with substrates. In order to calculate the Neel temperature ($T_N$) and magnetic properties, we need to extract the exchange interaction constants from the classical Heisenberg model and DFT results, which we evaluated up to the fifth nearest neighbors (J1-J5). Finally, the exchange coupling constants were used as parameters in the atomistic spin model i.e., Monte Carlo simulation and the Landau–Lifshitz–Gilbert (LLG) equation to calculate its magnetic properties such as magnetization ($M$), magnetic susceptibility ($\chi_M$), $T_N$, and hysteresis loop etc. Moreover, the LLG equation is also used to visualize and simulate spin dynamics of chromia films.
Keywords : Antiferromagnets, Exchange interaction constants, Neel temperature, Atomistic spin model
References
[ 1 ] Saha, C. N. (2020). Fabrication of Micron Scale Test Structures for Magneto-Electric Chromia ($Cr_2O_3$) Thin Films (Doctoral dissertation, State University of New York at Buffalo).
[ 2 ] Sun, C. (2018). Structure Study of Magnetic Thin Films for Voltage Controlled Spintronics by Scanning Transmission Electron Microscopy Experiment and Density Functional Theory Calculations. The University of Wisconsin-Madison.
The recent experimental and theoretical search for near-room temperature superconductors
have shed light of interest on metal hydride as the critical temperature can vary from a
few kelvins to over 200 kelvins. One problem occurring in the theoretical research of the
material is that the traditional way of studying thermal superconductivity material is through
calculation of electron-phonon spectral function which cost enormous amount of time and
computational resource. Here we propose machine learning method (Support vector machine)
to classify the critical temperature of the material without calculating electron-phonon spectral function. The features used in the model are based on electronic properties occur from
hydrogen atom in the molecule and consideration effect of electron localization function
which have strong correlation to the temperature, this set of features can be obtained faster
and with less computational resources than directly find the critical temperature. Decision
boundary from the model can categorize most material in the dataset and thus speed up the quest for future high-temperature hydrogen-based superconductors.
Vanadium pentoxide (V2O5) is one of the promising cathode materials for Mg-ion batteries owing to its high capacity, safety, and low toxicity. However, it still suffers from sluggish charge transport kinetics and low stability. To overcome these problems, experiments reported that using aqueous electrolytes dramatically improves ion diffusion and capacity of V2O5-based cathode. Proton from water in the electrolyte may alter battery performance but its role remains unclear. Herein, we used density functional calculations to examine the effect of proton on the improved charge transfer properties and stability of Mg-proton co-intercalation to reveal the role of aqueous electrolyte. We find that protons prefer to intercalate into V2O5 and reside at vanadyl oxygen atoms. Upon proton intercalation, the band gap of V2O5 decreased from 2.17 eV to 0.07 eV suggesting better electronic conductivity. In addition, it improves Mg-ion diffusion where the diffusion barrier is reduced from 0.89 to 0.49 eV in the vicinity of intercalated proton. This work unravels the role of water in electrolyte in the enhanced cathode performance which could be used to better design cathode materials or electrolyte for Mg-ion batteries.
Over the last decade since the discovery of graphene, two-dimensional materials have gained a great attention due to their outstanding properties suitable for fabrication of next generation nanodevices. A single-layered diamond or diamane, whose high stiffness and high thermal conductivity are inherited from its bulk counterpart, is a candidate for heat dissipating device applications. Unfortunately, pristine diamane is structurally unstable without passivation of dangling bonds on it surfaces by H, F, and OH. Recent theoretical studies have suggested that site-specific substitution of N for C can stabilize the diamane’s structure without surface termination. Despite its superhard properties inherited from bulk carbon nitrides, thermal properties of N-substituted diamane have not been explored. In this work, we investigate thermal properties of N-substituted diamane using density functional theory and Boltzmann transport equation in the relaxation time approximation. Our results show that the flexural phonon branch, which is typically observed in two-dimensional materials, appears in the phonon dispersion relation of N-substituted diamane and it contributes large thermal conductivity to the material. Also, we estimate the thermal conductivity of N-substituted diamane as a function of temperature, and the results are discussed in comparison with that diamond.
Transition-metal carbides/nitrides (MXenes) and their alloys, the largest family of two-dimensional materials, are gaining a lot of attention in the material research community due to their high potential in many applications, e.g., batteries, supercapacitors, electromagnetic and interference shielding. In this work, we investigated the thermodynamic stability of ((Ti$_{1-x}$V$_x$)$_{1/3}$Mo$_{2/3}$)$_3$C$_2$ MXenes (TVMCs), using the first-principles calculation based on density functional theory and cluster-expansion formalism. Our results suggest that Mo atoms prefer to substitute in the outer metal layers of TVMCs, and such occupying behavior is a crucial factor that determines the thermodynamic stability of TVMCs. On the other hand, Ti and V atoms residing in the inner metal layer of them are predicted to weakly interact with each other and their atomic configuration has a minimal impact on the stability of TVMCs. The transition temperatures between configurational order and disorder phase whose Ti, V, and Mo atoms reside in TVMCs have been predicted, and the possible existence of configurationally disordered TVMCs has also been discussed.
This work presents fabrication and characterization of a p-n junction in Si. The p-n junction was fabricated simply by thermal diffusion of n-type Si wafer with boron deposited on the surface. The depth of the p-n junction was primarily predicted by the Fick’s law of diffusion. Boron deposition was carried out in a vacuum system using an electron beam evaporator. The deposited samples were annealed in the same vacuum system to introduce boron diffusion into the Si substrate. V-I curve measurements were performed to characterize the electrical properties of the p-n junction. Appropriated depth and width of depletion region will be discussed for application of X-ray detectors.
Keywords: boron diffusion, p-n junction, thermal annealing, electron beam evaporation, silicon semiconductor
The outbreak of COVID-19 affects a daily life of human beings so protective equipment such as surgical masks is become essential. In this research, the development of filter layers for surgical masks from poly butylene saccinate (PBS) fiber nanocomposite which is a biodegrable polymer and copper nanoparticle (Cu NPs) that can inhibit microorganisms and can be synthesized from organic substances by electrospin technique, The spinning condition at a potential difference of 20 kV and a speed of 40 ml/hour was used in nanofiber fabrication. By using a co-solvent system between chloroform and dichloromethane, a composite solution was prepared. From scanning electron microscopy technique, it was found that the nanofiber size of polybutylene saccinate was 750 nm, However, when comparing with the size of PBS composite nanofibers were not significantly different. Further, the antimicrobial inhibition of nanocomposite was performed using 0.1% with CuNPs. Then, physical properties such as absorbance properties will be studied by UV-visible spectroscopy. Mechanical properties of nanofibers will be test by UTM. Additionally, the pressure of air passing through the filter layer will be test in order investigate its application in surgical mask.
Giant dielectric (GD) ceramics have been extensively reported in recent years due to their potential for use in high−performance capacitors. However, the strong temperature stability of high dielectric permittivity ($εˊ > 10^3$) and low dielectric loss tangent (tanδ < 0.05) have been difficult to accomplish. In this work, a novel GD oxide was discovered in (Tb+Nb) co−doped $TiO_2$ (TNTO) ceramics. Their colossal εˊ (~$4.7−5.3×10^4$) and ultra−low tanδ (~0.006 − 0.007) were achieved at 30℃ and 1 kHz. Moreover, their temperature coefficient of εˊ (Δεˊ /εˊ ) values at 1 kHz were less than |±15%| over the temperature range from −60℃ to 210℃, which encounter the primary desire in X9R−type capacitor. Interestingly, their low tanδ (~ 0.033−0.045) still appears at 200℃. These outstanding dielectric behaviors of TNTO ceramics were investigated via characterization of their phase structures, microstructures, and impedance spectroscopy (IS) analysis. The observation of electrical heterogeneity of semiconducting grains and high insulating layers indicates that interfacial polarization exists in the TNTO ceramics leading to the GD behaviors. Besides, the dispersed second phase particles in their microstructures could reduce their εˊ and tanδ values. Therefore, the appropriate second phase particles fraction could tune the TNTO’s dielectric properties as required.
Siam Photon Source II (SPS-II) will be the first and only 4th generation synchrotron light source in South-East Asia region upon its completion. The accelerator complex consists of a 150 MeV linac and 3 GeV booster synchrotron combination acting as an injector, and a 3 GeV electron storage ring based on a modified 6 Bend Achromat (6BA) lattice. The modified 6BA, or Double Triple Bend Achromat (DTBA) lattice, is adopted because the emphasis is put on maximum utilization of the medium-size storage ring. It is planned that several components will be manufactured domestically. A half-cell prototype of the SPS-II storage ring was successfully developed, demonstrating the domestic fabrication capability. In this talk, the details of the machine design along with prototype development will be described.
Since discovering of radioisotope materials, scientists and engineers tried to apply them into many ways to take the advantage from its penetration characteristic. This paper aims to introduce its usefulness as an important tool for process investigation in petroleum and petrochemical plants. Mostly, petroleum and petrochemical plants are continuously operating for more than three years per cycle before a turn-around maintenance. During the operation, the malfunction could be possible and may cause the process upset, consequently, the products are out of specification. The applications can be one or more than one of three techniques, i.e. transmission technique, emission technique and back-scattering technique. Mostly, transmission and emission techniques are using gamma rays sources ($^{60}$Co and $^{137}$Cs) while back-scattering technique used to neutron source ($^{241}$Am-Be) and thermal neutron detector. The examples of gamma ray applications for transmission technique are pipe-scan, on-steam distillation column scan, scanning of heat exchanger, radiographic testing, and industrial computed tomography. Whereas the emission techniques are using radiotracer for leak detection in heat exchanger, residence time distribution, etc. The examples of neutron backscattering applications are the sludge level in vessel determination, water accumulation in concrete foundation, and water accumulation in thermal insulation materials. The petroleum and petrochemical industries in Thailand have understood the benefits of utilizing these techniques. The result from investigation can be used for preventive and corrective maintenance, process optimization, problem shooting as the result of techniques can identify the location of problem precisely. The usefulness of stated techniques has proven to have significant roles in certain applications which could not be replaced by other inspection techniques.
The mechanism behind the biological sparing effect with ultra-high dose rate (FLASH) still remains unknown. One possibility is that the FLASH effect is caused by oxygen removal or the reaction of radiation-induced radicals with oxygen during irradiation. In this work, before studying the oxygen removal with FLASH irradiation, we decide to irradiate the samples with conventional dose rate (CONV) to investigate experimental oxygen removal in different liquids and study the radical production and reactions that arise in this dose rate range, for reference. Water samples were exposed to 50 Gy X-ray radiation dose at the dose rate of ~4.7 Gy/min. Each sample was irradiated for 2-3 irradiations. Dosimetry for the X-rays source was carried out using a Semiflex ionization chamber. The oxygen measurement was performed using a chemical optical sensor and observed online. The oxygen depletion was the highest in the first irradiation and then decreased in steps afterwards with the average values of 0.28, 0.25 and 0.23 μM/Gy in the first three irradiations, respectively. From the experimental results, we conclude that the decreasing behavior of oxygen removal is produced by the radical production and their reactions which compete with oxygen removal. The radicals created in previous steps might react with each other and reduce the reaction that should occur with the oxygen in the next irradiation. In addition, an increased oxygen removal was found in solutions containing organic molecules.
The ELM phenomenon in fusion plasma is studied based on bifurcation concept. Three field transport equations including thermal, particle and toroidal momentum transports are solved simultaneously, resulting in the spatio-temporal prediction of plasma pressure, density, and toroidal momentum profiles. The transports include both neoclassical and anomalous effects with the velocity shear dependent suppression effect acting on only the anomalous channel. The results show plasma pressure, density and toroidal momentum profiles versus time and radius. It is found that the plasma can transit to H-mode once the threshold power is reached, resulting in the formation of an edge transport barrier. A peeling-ballooning model of edge localized mode, ELM, is included in form of thermal loss once the critical pressure gradient and current density has been reached. Frequency and amplitude of ELMs are investigated. The results exhibit ELMs phenomenon in which a periodically drop of pressure, hence a loss of energy can be observed. It is also found that changing of other model variables affect frequency and type of ELMs. This research is supported by TSRI Fundamental Fund project number 91526.
Boron neutron capture therapy (BNCT) is a type of radiation therapy that utilizes the interaction of a stable boron ($^{10}B$) isotope and a thermal neutron to generate high-LET alpha and $^7Li$ particles that disrupt tumor cell DNA. Due to the low penetrating properties of alpha, the interaction is confined within cancer cells, and normal tissues are spared. BNCT has been demonstrated to be effective against specific types of cancer, including glioblastoma (GBM). The aim of this study is to apply BNCT to cholangiocarcinoma (CCA), which is a malignant tumor most prevalent in the northeastern part of Thailand. First, we measured L-p-Boronophenylalanine (L-BPA) accumulation in CCA cells using ICP-MS. Then, the survival curves of CCA cells exposed to neutron irradiation were investigated. The results show a relationship between neutron flux and the survival rates of CCA cells in our in vitro experiments. This gives us some insight on how to apply BNCT in CCA treatment.
Cosmic rays are high-energy particles from space, i.e., the sun, the supernova explosion of stars, and other currently unknown sources by processes that are not fully understood. Magnetic fields influence the propagation of these particles in the solar wind and the magnetosphere of the Earth. We can investigate changes in these magnetic fields by recording variations and fluctuations in the cosmic ray intensity. Ground-or-sea-based neutron monitors are a standard tool for detecting atmospheric showers from 20 GeV-range primary cosmic rays of either solar or galactic origin. Configurations of neutron detectors may not be completely identical, and these differences lead to different energy-dependent effective areas (yield functions). Near Polar regions, the earth's magnetic field is less effective in keeping cosmic rays from reaching the atmosphere than near the equator; so lower-energy particles from the sun are admitted. We, in Thailand, have developed portable neutron monitors to investigate the energy spectrum of cosmic rays during ocean voyages to/from Antarctica and its solar modulation, i.e., variations over the typically 11-year sunspot cycle. The interesting new findings from these voyages and future approaches will be discussed.
This study investigates the enhancements of relativistic electron flux (MeV) in the outer radiation belt that can cause anomalies of geosynchronous satellite systems. The enhancements occurred during High Intensity, Long Duration, Continuous AE Activity (HILDCAA) of 12 events during 2015 - 2017. The relativistic electron (0.8 - 2.0 MeV) flux measured by GOES-13 satellite and low-energy electron (40-130 keV) flux measured by POES satellite are examined. Results reveal that, in the long recovery phase, the relativistic electron flux increases, while the low-energy electron flux decreases. Typically, the enhancements of E > 0.8 and > 2.0 MeV electrons occurred promptly and ∼1.0 day after the HILDCAA onset, respectively. Case studies show that the peak flux of > 2.0 MeV occurred about 2 days after the onset of short-period HILDCAA, while it occurred 4 days after the onset of long-period HILDCAA. The HILDCAA events with high amplitude and long-lasting Alfven waves with low solar wind dynamic pressure are associated with the long-lasting of sporadic injection of low energy electrons into the nighttime magnetosphere during the period of prolonged substorm (AE) activity.
The solutions of sine-Gordon equation will be used as the series solution for determining the kink solution of Oskolkov equation. The matching coefficients and choosing the some parameters of the series can provide the suitable solution. The numerical calculation with the kink soliton as the initial condition shows the stable solution can be found by this expansion method.
Recent discoveries regarding the existence of the large–scale structures in the universe, especially on the scales where the Cosmological Principle is expected to be accurate, pose a challenge to the Standard Model of Cosmology (ΛCDM model). These structures extend beyond 200 – 300 Mpc (Haines, Clowes, and Campusano, 2000; Gott III et al., 2005; Clowes et al., 2013; Horváth, Hakkila, and Bagoly, 2014, Lopez et al., 2021) provide strong evidence of anisotropy against the ΛCDM model as there should not be clumping of objects within that scale. The work of Migkas et al. (2020, 2021) also observed a similar anisotropic behavior of galaxy clusters towards a particular direction in the night sky. However, there is still no clear explanation for how to explain these observations. From this, the researcher aims to describe these anisotropies and their nature by viewing them through a theoretical lens.
We outline a new model in which generalised uncertainty relations, that govern the behaviour of microscopic world, and dark energy, that determines the large-scale evolution of the Universe, are intrinsically linked via the quantum properties of space-time. In this approach the background is treated as a genuinely quantum object, with an associated state vector, and additional fluctuations of the geometry naturally give rise to the extended generalised uncertainty principle (EGUP). An effective dark energy density then emerges from the field that minimises the modified uncertainty relations. These results are obtained via modifications of the canonical quantum operators, but without modifications of the canonical Heisenberg algebra, allowing many well known problems associated with existing GUP models to be circumvented.
A new notion of integrability called the multi-dimensional consistency for the integrable
systems with the 1-form structure is captured in the geometrical language both in classical
and especially quantum realms. A zero-curvature condition, which implies the multi-
dimensional consistency, will be a key relation in context of Hamiltonian operator.
Therefore, the existence of the zero-curvature condition directly leads to the path-
independent feature in a mapping (which will be expressed in terms of the Wilson line),
namely unitary multi-time evolution operators in the Schrödinger picture, introduced to
alternatively capture integrability of the systems. Another important result is the
formulation of the continuous multi-time propagator. This new type of the propagator
exhibits the path-independent feature on the space of time variables. Consequently, a new
perspective on summing all possible paths unavoidably arises as not only all possible paths
on the space of dependent variables but also on the space of independent variables must be
taken into account.
Coiling of rope, fed from a height onto a rotating plane, progresses through a sequence of shapes, a hypotrochoid to an epitrochoid to a circle as frequency of plane increases. Feeding velocity controls the rate of length deposition on a plane and frequency of plane controls the rate of length transfer from a contact point, where rope first touches a plane. Formation of secondary loops of a hypotrochoid or an epitrochoid results from the faster deposition rate than the transfer rate. When these two rates are comparable, secondary loops disappear so the shape returns to a circle like in rope coiling on a static plane. In a reference frame corotating with rope, the Coriolis and centrifugal forces act only at the contact point, not extending to the portion of rope far above a rotating plane. For small deflection of rope, tension is inferred from the equations of motion with using the radius and frequency of a primary loop measured in experiments. Tension changes continuously at both the hypotrochoid-epitrochoid transition and the epitrochoid-circle transition, reminiscent of the features of a second order phase transition.
Understanding of the dynamics of stars around the black hole is still incomplete. The Hubble Telescope discovered an evidence of the orbits of stars in the galactic centre that do not follow the Kepler’s laws. In this work, we study the classical effects on the periastron shift. We select the Hernquist potential function for the galactic bulge to examine the rate of change of periastron angular position. We propose a computational approach based on the principle of classical mechanics to study that shift. As a result, we find that the initial speed of the star affects the orbit shape. For a selected initial speed, we get a precession rate of approximately 0.69, in arbitrary units. We expect that our numerical method is able to apply to other models of galaxies.
Galaxy haloes evolve through complex structure formation processes. Feedback from active galactic nuclei (AGN) plays an important role on the formation and matter distribution in haloes. We investigate the effect of AGN feedback on the shape of dark haloes formed in the EAGLE simulations and trace the evolution. Haloes from the 50 Mpc box simulation with and without AGN feedback are extracted at redshifts 0, 0.25 and 0.87, with high ($10^{13} -10^{14.5} M_☉$), intermediate ($10^{12} -10^{12.5} M_☉$), and low ($10^{11} -10^{11.5} M_☉$) mass ranges, containing approximately 20, 100 and 800 haloes at redshift 0, respectively. We average the triaxiality profile of haloes in each mass range at different redshifts. The triaxiality at ${r_{200}}$ for the highest mass range for both simulations is simililar at all redshifts, but differ near the centre ($r<0.1 r_{200}$). The effect of AGN on the shape is more pronounced at low and intermediate mass ranges, with haloes in the AGN simulation progressively become more prolate internally as they evolve to the present. However, shape of individual dark haloes may also be affected by other processes. We follow the evolution of triaxiality of 3 most massive haloes and find that outside ${0.1r_{200}}$ the haloes exhibit change of shape erratically which could be due to merging. We conclude that AGN can affect the internal shape of haloes particularly in low and intermediate mass ranges, and that haloes are triaxial objects as a result of undergoing structural change through time.
The Evanescent Wave Coronagraph, EvWaCo, is an in-development prototype coronagraph, designed for use on the 2.4m Thai National Telescope (TNT), in the R and I-band filters. This work examines the astronomical capabilities of EvWaCo using the results from Fourier-analysis simulations. The coronagraph mask comprises a spherical lens placed in contact with a prism, utilising the principle of frustrated total internal reflection. On-axis light is transmitted through prism and the lens, whereas off-axis light is totally internally reflected within the prism, producing the mask’s coronagraphic properties. Fourier optics simulations were applied to the EvWaCo prototype to analyse its performance, combining different sources of contrast degradation that will be present in the system. The simulations used for the main analysis assume a good night at the Thai National Observatory (TNO) and include the fitting error, aliasing and wave-front noise, providing a radially averaged contrast curve. From the contrast curve, the detection limit, as defined by a minimum signal to noise ratio of 5 for a typical observation time, can be calculated for different primary star magnitudes. The relative fluxes of various binary stars, with a range on spectral classes and separations, were modelled allowing comparison to the EvWaCo detection curves. The photon-noise limited detection curves provide a theoretical baseline for the performance that will be achieved with EvWaCo; they therefore give an indication of the types of objects EvWaCo can observe. Along with a broader discussion of observable objects, some potential known candidates for observations on the TNT using EvWaCo are suggested.
To detect distant, low-mass exoplanets, the microlensing technique has been proven to be one of the most successful techniques. On the other hand, to detect the Earth as a rocky planet in the Solar system, the other technological civilisations could also use the microlensing technique. Assuming that technological civilisations have equal chance to be located around any star anywhere in the Galaxy, we can define the “Earth microlensing zone'' (EMZ) as the region of the sky from which observers may most likely see Earth's microlensing signal. The EMZ can be thought of as the microlensing analogue of the Earth Transit Zone (ETZ) from where observers see Earth transit the Sun. Just as for the ETZ, the EMZ could represent a game-theoretic Schelling point for targeted searches for extra-terrestrial intelligence (SETI). To compute the EMZ, the Gaia DR2 catalogue with magnitude G<20 is used to generate Earth microlensing probability and detection rate maps to other observers. We then show that Earth could be observable on average of thousands per year.
Interstellar complex molecules can be formed in interstellar molecular clouds during the process of star formation. Those complex molecules can be later delivered to planets to serve the role of the building blocks of life. Therefore, understanding the interaction and formation processes of those complex molecules in interstellar conditions is crucial to the understanding of the origin of life. Interstellar complex molecules are thought to be formed in a solid phase, on a surface of icy dust grains in molecular clouds. The regions where the formation of the complex molecules occurs are generally cold with temperatures below 100 K and pressure of 10$^{-10}$ mbar. Here we present the development of the astrophysical laboratory to study interstellar surface chemistry. The laboratory includes an experimental station to mimic the extreme conditions of interstellar molecular clouds and computational modeling of the chemical processes that occur in the interested physical conditions. The experimental station will be located at the PBP-CMU Electron Linac Laboratory, with the collaboration between NARIT, CMU, SUT, and SLRI. The setup includes an ultra-high vacuum chamber pumped to 10$^{-10}$ mbar as the main chamber for the experiments. Connected to the sample holder in the main chamber is a liquid nitrogen dewar to maintain the temperature of around 80 K. The water and the interested molecules are injected through the gas injection unit onto the cold surface of the substrate to form an interstellar ice analog. The chemical products will be probed with mid-IR and far-IR from the FTIR spectrometer by the MCT detector connected to the chamber. Finally, we present examples of the experiments that can be done with this experimental setup. The experiments will allow us to understand the structures, intermolecular interactions, and formation processes of the complex molecules in interstellar cloud environments.
Understanding the extraterrestrial origin of ribose, as one of the subunits of ribonucleic acid (RNA), is crucial to anticipating the formation of the building blocks of life under interstellar medium conditions. Under ordinary atmospheric conditions, the formation of sugar is suggested to occur through the formose reaction, where formaldehyde is solely used as the precursor in each of the iterative steps of the processes. On the other hand, sugar synthesis under interstellar medium conditions has evidently been shown to be significantly different from the terrestrial formose reactions due to the extremely low density of molecules and the very low temperature. In this study, we theoretically investigate the formose-like reactions for ribose formation catalyzed by a single proton through the mean of computer simulation based on first-principles density functional theory (DFT). The ribose formation reactions are modelled in the absence of solvation effects at absolute zero temperature to mimic the extremely low pressure and temperature found in interstellar molecular clouds. We observe that the presence of a proton gives rise to a more thermodynamically stable complex of the two reactive carbonyl compounds by bridging their oxygen atoms as required for the iterative formose reaction to proceed. In order to form a new carbon-carbon bond through an iterative process, only the region where the additional formaldehyde attaches to the existed protonated carbonyl compound is of great importance. Similar energy barriers for all the iterative steps during the ribose formation have been observed to be approximately 67 kcal/mol. Our findings show that a single proton can act as an efficient catalyst for the gas-phase ribose formation reactions. The results suggest that ribose formation can preferentially occur via the formose pathway in the presence of protons, which are presented in interstellar clouds.
The National Astronomical Research Institute of Thailand (NARIT) is currently developing new low resolution and high-resolution spectrographs for the Thai National Telescope. These instruments will be used for follow-up observations for spectral type characterisation and exoplanet detections. Such observation typically will need long exposure (> 1 hour) where the target has to stay inside the slit of the spectrograph during the observation. Therefore, information on the pointing accuracy and the tracking performance of the telescope is essential as part of the preparation works for these two instrumentations.
To gather these information, we look into past science data collected with the 2.4-m telescope between 2014 to 2022. These photometric data are then re-analysed to obtain the pointing coordinates and the x-y position of the target on the CCD. We choose only science data where the observations cover at least 4 hours or longer for the tracking analysis.
Our results show that the Thai National Telescope has a satisfactory pointing accuracy where in most cases, the targets are positioned within 5-40 arcseconds from given coordinates. While such accuracy is acceptable for photometric observation, it will pose a problem for the spectrographs because the width of the slit is usually only a few arcseconds. As for the tracking, we found that the telescope has a good tracking (drift <5 arcsec/hour for ULTRASPEC) with an exception for targets near the zenith with declination close to 18^{\circ}. However, we also found that the tracking after 2019 is worse compared to previous years. Further investigations are needed to find the cause of this issue.
I will present the first result of our project on the search for high-degree nonradial pulsations in the very fast rotating bright A-f stars.
These pulsations look like the tsunami waves running over the stellar equator to the direction of rotation (prograde waves).
To search for the pulsating candidates, we used the photometric data from the NASA space telescope TESS and the high- and medium-resolution spectroscopy obtained with 2m class telescopes located in Europe and with the Thai National Telescope.
For all candidate stars, we discovered prograde waves having very large amplitude on the surface. We discussed the identification of the spatial structure of these oscillations.
The 21-cm neutral hydrogen (HI) survey is an important probe for cold gas and galaxy evolutions in the local and low-redshift universe. One of the key measurements used to study evolution and properties of local star-forming galaxies is the HI mass function (HIMF). Among the interested topics in modern astrophysics, the study could potentially shed more light and offer explanations for the discrepancy between the $\Lambda \text{CDM}$ standard model prediction and observed HI-galaxy number density (e.g. ALFALFA, HIPASS). The simulation also over-predicted the abundance of small satellite and low-mass galaxies. Both problems still requires sensitive instruments for more larger and deeper HI surveys to detect the populations of low-mass HI-galaxy. Currently, the HI-galaxy surveys could only reach down to $ \sim 10^7 $ Solar mass (M$_{\odot}$). Since, the next-generation radio surveys such as FAST or Australian Square Kilometer Array Pathfinder (ASKAP) will provide deeper any more sensitive data for reaching lower HI-mass and high-redshift HI-galaxies. The HI source catalogs from cosmological simulation (mock catalogs) are used to determine the expected HIMF from the upcoming HI surveys. We aim to compare the variability in the HIMF obtained from various mock catalogs, which were simulated with different parameters and purposes. This work also demonstrates the dissimilarities between the HIMF from recent semi-analytic model and the observed HIMF. Moreover, we aim to create an accurate mock catalog for the upcoming large HI-galaxy survey with the focus on calibrating the calculation of HIMF using both $1/V_{\text{max}}$ and 2DSWML determination methods. We therefore determined the HIMF from various mock catalogs (e.g. Multidark, Boishoi and Millennium), which the HI mass was evaluated by using the cold gas mass for each object. We found that the HIMF are relatively diverse on $ \le 10^7 \text{M}_{\odot} $ HI mass compare to the observed HIMF, which could be the effect of the mass resolution of the mock catalogs.
We investigate how the local and temporal variation in the speed of light may help alleviating the Hubble tension problem. The idea is motivated from the observed variation in the fine structure constant from spectra of quasar absorption systems which could potentially be caused by the change in the speed of light. To test the hypothesis, we use the data from Pantheon Supernova which contains 1,048 spectroscopically confirmed type Ia supernova within redshift range $0.01 < z < 2.3$. From our model, we find that the variation in the local speed of light $\Delta c / c = (-1.63 \pm 2.65) \times 10^{-5}$ and the temporal variation in the speed of light is $(1/c)({\rm d}c/{\rm d}t) = (5.45 \pm 4.37) \times 10^{-20}$ year$^{-1}$ which gives a slightly better constraint from any measurements to date. It is still inconclusive whether the data prefers larger or lower value of the speed of light in the past due to a large uncertainty. However, in all our models of variation in the speed of light, the Hubble tension problem is alleviated by having a lower value of $H_0$ at $69.84 \pm 3.94$ km s$^{-1}$ Mpc$^{-1}$ and $\sim1\sigma - 2\sigma$ difference to the early-time value. Such a simple model has a potential leading to our better understanding of how the Hubble tension arises and our presumption to the laws of physics which may not hold true across the cosmic time.
It is widely believed that star-forming spiral galaxies stop their star formation activity and eventually evolve into the passively evolved elliptical galaxy. One of the key factors is the gas outflowing process that depletes the star-forming ingredient in the galaxy. In 2017, we reported the systematic search for large-scale outflowing galaxies at $z=0.1-1.5$ covering the past 9 billion years of the universe. However, due to the small comoving volume at low redshifts, we could not detect any candidates at $z<0.40$. In this study, we redo the search with newly available imaging data from Subaru/Hyper Suprime-Cam legacy survey. We found 819 candidates with large-scale outflow at $z=0.1-1.5$. The number of samples increases more than 10 times as compared with the previous study. With this new result, we can make a meaningful constraint on the evolution of galaxies with gas outflow on a scale large enough to go beyond their stellar component. We also found that extended emission indicating the gas outflow is rather concentrated in the galaxy cluster than in the individual galaxy. Further study with follow-up spectroscopic observations shows that the gas outflow found in most samples originates from the intense star formation in a density-bounded ionization state without any evidence of fast radiative shock.
The cosmos consists of various elements, which have many different isotopes. Some of those isotopes are stable nuclei, but some of those are radioactive nuclei. However, some radioactive isotopes have exotic properties, and these nuclei cannot be explained by the shell model. In this work, we studied the light neutron-rich nuclei, He-6, by using the halo structure model. We applied the Wood-Saxon potential and the hyperbolic cosine potential to calculate the nuclear density. We also compared our calculation results to the experimental results of He-6.
Blazars are a class of active galactic nuclei whose jets are aligned with the observer’s line of sight. They are powerful multi-frequency emitters that exhibit rapid and violent variation. Based on optical emission lines, blazars are classified into two subclasses which are BL Lacertae objects (BL Lacs), and flat spectrum radio quasars (FSRQs). Various studies have shown that besides using emission lines, it is possible to use blazar variability to classify blazars into the aforementioned subclasses. We are investigating the use of blazar variability for blazar classification by using it as inputs in machine learning algorithms. In this work, we use the 5th edition of the Roma-BZCAT catalog as a reference. Optical and radio light curves are taken from 3 facilities, namely, Zwicky Transient Facility (ZTF), Gravitational-wave Optical Transient Observer (GOTO), and Owen Valley Radio Observatory (OVRO), observed during 2019-2020. From the data, we study the statistics of blazars variability which in turn are used to inform features extraction for machine learning. We will report on the results of the study, challenges, future opportunities, and discuss the classification performance. There are 766 BL Lacs and 1288 FSRQs in the analysis, each of which has at least 10 data points in both g and r band of the ZTF data. The light curves from the entire observation period are used to find the relation between g-r color evolution and the fractional variability in the r band. The pearson correlation of the relation is 0.73, while the spearman correlation is 0.76. The correlation values suggest that when blazars are more active in the g band, the variabilities in the r band tend to be less.
This research aims to study photometric variability and Fourier analysis of High Amplitude Delta Scuti stars (HADS), which are interesting short period variable stars with spectral types between A2 and F0. They are located in the area of the classical cepheid instability strip, which crosses the main-sequence (MS) on the Hertzsprung-Russell (H-R) diagram. The CCD photometric V-magnitude data of the selected HADS stars were acquired based on the AAVSO international database (American Association of Variable Stars Observers), which is the largest and most comprehensive digital variable star database. Time-series light curve data was accomplished using discrete Fourier transformation. The pulsating properties of the selected HADS stars were analyzed using the Period04 astronomical program. We obtained the times of maxima, magnitude changes and pulsation frequencies for each star. The study of the pulsation frequencies, O-C diagram, and period change of HADS stars can estimate their pulsation modes and their evolution. HADS stars are very important as standard candles that can be used to measure galactic distances.
Galactic cosmic rays (GCRs) are energetic charged particles, mainly protons originated in supernova remnants. Near Earth, GCR intensity ($n$) is subjected by modulation mechanisms in the solar wind, which are changed along the solar cycles (SCs) indicated by heliospheric magnetic field (HMF). We have used GCR count rates as observed by neutron monitors at low-to-high cut-off rigidities ($P_c$) and polarity states ($A$) of the HMF to determine the North-South (NS) asymmetry of the $n$. The study times span the SCs 22/23, 23, and 24 during periods 1996–1998 ($A>0$), 2004–2008 ($A<0$), and 2015–2019 ($A>0$), respectively. By using a new simple correction method for secular changes for $n$, we calculated the NS asymmetry of $n$ denoted as $\delta {n_{{\rm{S - N}}}}/n$ with respect to the heliospheric current sheet (HCS) which is a thin region with large-scale wavy structure separating the north and south HMFs. The NS differences of corrected HCS tilt angle [$\alpha$] for Earth’s excursions in helio-latitude denoted as $\Delta \alpha _{{\rm{N - S}}}^{\rm{E}}$ show a comparably consistence and anti-correlation with the corrected $\delta {n_{{\rm{S - N}}}}/n$ particularly during $A<0$ epoch (2004-2008) and $A>0$ epoch (2015-2019 not 1996-1998). The aspect suggests the importance of heliospheric drift on asymmetric modulation and latitudinal gradient of GCRs in both periods. The unidirectional latitude gradient [${G_ \bot }$] derived from the relation of the consistencies between corrected $\delta n_{S-N}/n$ and $\Delta \alpha _{{\rm{N - S}}}^{\rm{E}}$. We found a strong positive correlation between $\delta {n_{{\rm{S-N}}}}/n$ and ${G_ \bot }$ for all epochs and $P_c$ .
We investigate the characteristic spectrum of Hydrogen atoms subjected to the gravitational wave (GW) produced by a compact binary inspiral, particularly the supermassive black hole binary (SMBHB). These atoms are assumed to be distributed in the source’s local wave zone. The gravitational wave is mathematically described by the quadrupole formula of the linearized theory of General Relativity. The energy shifts and the spectrum of Hydrogen atoms are computed by the first-order perturbation theory in non-relativistic approximation. The effect of GW perturbation is analyzed in a strong-field, a weak-field, and an intermediate-field regime. The extraction of source parameters from the spectrum is also discussed.
Standard time and frequency are widely implemented in many systems: global navigation satellite system, high speed communication, and financial technology. Each application requires different accuracy and stability. Atomic clock has been used as the precise oscillator. In 1967, the energy level between two hyperfine ground states of Cesium 133 at 0 K has been defined as the standard unit of time. However, the next generation of the atomic clock, called “Optical Clock” has illustrated the uncertainty below 10$^{-17}$. The optical transition of various atoms and ions are selected as the second representative of second. NIMT has developed the next generation of atomic clock using an Ytterbium ion. The core technology i.e., electronics control, helical resonator and linear quadrupole trap has been designed and built in Thailand. The system has been successfully trapped single ion of Yb174.
We build a quantum diamond spectrometer (QDS), outlined by Bucher et. al [1], to study the fluorescence of the nitrogen-vacancy (NV) center in diamond, a quantum defect that can be used as a qubit or quantum sensor. The QDS has several advantages to a traditional confocal microscopy, particularly in terms of measurement speed. The setup consists of a green laser excitation onto the diamond that is placed on an optical light guide for fluorescence detection. A microwave loop is then placed onto the diamond to deliver oscillating magnetic field to probe the NV center transition. Finally, permanent magnets are attached to a kinematic stage for tuning the transition energy of the NV center. With this setup, we can adjust the magnet distance, azimuthal angle, and polar angle with reference to the NV center axis for optimizing NV center fluorescence. We demonstrate measurements of NV center fluorescence as a function of microwave frequency and show the intensity drop at 2.87 GHz, showing the interaction at zero-field splitting, and measurements of the Zeeman splitting of NV center electronic spin from an external magnetic field in different orientations. The results can be used to perform vector magnetometry, which has potential applications in quantum sensing.
[1]. Bucher, D.B., Aude Craik, D.P.L., Backlund, M.P. et al. Quantum diamond spectrometer for nanoscale NMR and ESR spectroscopy. Nat Protoc 14, 2707–2747 (2019).
Nitrogen Vacancy (NV) center is a defect in a diamond with unique optical transitions in the visible wavelength that is spin-dependent, allowing it to be utilized as an optical qubit or as a magnetometer. Our work primarily focus on magnetic field sensing with NV center, as they offer high sensitivity and high spatial resolution at the nanoscale level, along with ability to simultaneously measure magnetic field magnitude and direction. To exploit the NV center as a vector magnetometer, we use a confocal microscope retrieve photoluminescence (PL) emitted by the NV center, in combination with Optically Detected Electron Spin Resonance (OD-ESR) technique that probes the microwave frequencies corresponding to the NV electronic transition. In the OD-ESR, we vary applied microwave frequencies to change the spin population in the ground state triplet. If the applied microwave frequency is on resonance with the transition frequency between m_s=0 and m_s=±1, the measured PL will decrease. A magnetic field can be applied to split the m_s=±1 states, and the splitting depends on the magnitude and direction of magnetic field. As a result, two resonant transition frequencies can be used to determine the vector magnetic field experienced by the NV center, and four different orientations of the NV center in the diamond lattice can provide a complete 3-dimensional components of the magnetic field. In this work, we demonstrate simulated OD-ESR spectra of the NV center as a function of the magnitude and direction of the magnetic field. The results can be used to understand the experimental ODESR data in order to determine the magnetic field vector in nanoscale magnetometry, which can be used as quantum sensors.
Optical Coherence Tomography Angiography (OCTA) is a non-invasive imaging technique for microvasculature visualization. OCTA does not require injection of exogenous contrast agents, or fluorescent dye into blood circulation, which may cause allergic reactions as in fluorescein angiography (FA) and indocyanine green angiography (ICGA). OCTA differentiate blood vessel from static tissues by analyzing the variation of OCT speckle caused by moving particle in blood vessel. In this study, OCTA was implemented on a spectrometer-based spectral domain OCT that was built on Michelson interferometer. The OCT imaging systems was operated at 835 nm central wavelength with acquisition speed of 10,000 depth scans/s. Three methods of speckle analysis were implemented, i.e. Amplitude Decorrelation (AD), Speckle Variance (SV), and Intensity-to-Average Variance (IAV). Their performance for segmentation of blood vessels underneath skin were studied. In addition, the auxiliary methods of pixel averaging and split-spectrum were added to improve the signal-to-noise ratio of images. To compare the performance of the implemented algorithms, a flow phantom was constructed by embedding a capillary tube inside a petrolatum-based gel (tissue mimic material, or TMM). To mimic a blood flow beneath skin, dilute milk was pumped through the capillary with average flow speed of 2.0 mm/s by using a syringe pump system. The performances of each OCTA algorithm, in terms of signal-to-noise (SNR) ratio and contrast-to-noise (CNR) ratio, were measured and compared. The OCTA imaging system will be optimized for nailfold vasculature imaging. The ability to detect and visualize change in nailfold microvasculature pattern can help in diagnosis of many diseases, such as connective tissue disease, autoimmune rheumatic disease, ophthalmic disease, and coronary disease. Furthermore, OCTA technique is capable of in vivo volumetric imaging of capillary in real-time and hence can potentially be a powerful tool for skin diagnostics.
Inspired by random walks on graphs, the diffusion map (DM) is a class of unsupervised machine learning that offers automatic identification of low-dimensional data structure hidden in a high-dimensional data set. In recent years, among its many applications, the DM has been successfully applied to discover relevant order parameters in many-body systems, enabling automatic classification of quantum phases of matter. However, a classical DM algorithm is computationally prohibitive for a large data set, and any reduction of the time complexity would be desirable. With a quantum computational speedup in mind, we propose a quantum algorithm for the DM, termed the quantum diffusion map (qDM). Our qDM takes as an input $N$ classical data vectors, performs an eigendecomposition of the Markov transition matrix in time $O(\log^3 N)$, and classically constructs the diffusion map via the readout (tomography) of the eigenvectors, giving a total expected runtime proportional to $N^2\text{polylog}\,N$. Finally, quantum subroutines in the qDM for constructing a Markov transition matrix and for analyzing its spectral properties can also be useful for other random-walk-based algorithms.
Phase change correction is an important correction value of the end effect in an optical interferometry system. Normally, this value is used to compensate for gauge block measurement by an optical interferometry system based on ISO 3650:1998. Quartz plates and three different types of gauge block: steel, ceramic, and tungsten carbide were used in this study. Two different interferometric measurement systems in terms of fringe fraction (a phase shift method and an average slits method) were determined for the phase change correction by a five-stacking method. These results are used to determine the length measurement of gauge blocks in an optical interferometer technique and consequently, to evaluate the uncertainty of gauge blocks measurement. The preliminary results are shown that the value of phase change correction in a phase shift gauge block interferometer (PSGBI) system and a standard uncertainty are 35.3 nm and 6.2 nm, respectively. In contrast, the values from an average slits gauge block interferometer (ASGBI) system and a standard uncertainty are 66.0 nm and 6.4 nm, respectively. We found that the phase correction from the PSGBI system is lower than ASGBI about 20.6 nm because the PSGBI's wave-front correction is more complete than the systematic error of ASGBI leading to the low value of phase correction in the end effect. However, the lengths of gauge blocks of all three materials measured by the two different systems were consistent as assessed by En number. According to the study, we can conclude that phase change correction is based on the characteristics of each GBI system, material types of gauge block and optical plates such as the fringe fraction technique, and wavefront error compensation. Consequently, measurements that require a high accuracy should determine the phase change correction before each measurement due to this value is not interchangeable.