Súčasné technológie neumožňujú experimentálne študovať a overovať naše teoretické modely
a predstavy o fundamentálnych fyzikálnych javoch prebiehajúcich v takých astro-fyzikálnych
objektoch, akými sú čierne diery. Zatiaľ jediným spôsobom ako experimentálne verifikovať
tieto modely (a predstavy) o fyzike čiernych dier je nájsť laboratórny fyzikálny systém, ktorý
s istými obmedzeniami...
Quantum walks represent a generalization of the random walk to the coherent evolution of the
quantum particle on a graph or a lattice. We provide an overview of the concept, focusing on
the discrete-time quantum walk, and illustrate the applications in quantum simulations and
quantum computation. Finally, we introduce a very successful experimental implementation
of quantum walks which is...
Neutrinos are together with photons the most abandon particles in the Universe. The
knowledge of the neutrino mass is important not only for particle physics but also for
cosmology. Oscillation experiments proved that at least two of the known three neutrino mass
states have the mass different from zero, while at least one of these states has the mass greater
than 0.05 eV. Precision...
Magnetic nanoparticles (NPs), especially SPIO nanoparticles, have long been used as MRI
(Magnetic Resonance Imaging) contrast agents and as advantageous nanoplatforms for drug
delivery, taking advantage of their unique magnetic properties and ability to function at the
molecular and cellular level. In our centre smart design and development of SPIO
nanoparticles in mild conditions with...
Why are the III-nitride semiconductors so unique that they became the second most important
semiconductor material after silicon? Why it was so difficult to prepare high quality nitride
layers? It was so difficult that scientist, which have partly solved this problem were five years
ago awarded by Nobel Prize. What are the most perspective applications for nitrides? What
problems have to...
Photovoltaic solar energy conversion years has become a decisive part of the
electricity generation. The global installed photovoltaic (PV) capacity surpassed 600 GW in
2020 and the terawatt installed capacity is going to be achieved within the following decade.
The dramatic fall of costs made PV the cheapest source of new electricity generation (without
subsidies) in large part of the...
Recent breakthroughs in electrical detection and manipulation of antiferromagnets have
opened a new avenue in the research of non-volatile spintronic devices. Antiparallel spins in
antiferromagnets lead to the insensitivity to magnetic field perturbations, multi-level stability
and ultra-fast spin dynamics, which is also a major experimental challenge [1]. In this
contribution we show how...
Present state of elementary particles to be specified by a set of quantum numbers is
summarized. An existence of four types of interactions between elementary particles is
reminded with an emphasis that not all particles are able of all four interactions. Those to be
able of strong interactions are named “hadrons”- compound of “quarks”. Compound from
quark-antiquark are “mesons” and...
The ATLAS experiment is the largest particle physics detector installed at the Large Hadron
Collider at CERN, which measures the proton-proton (or lead-lead) collisions at the world-
highest energies. The precision measurements of the physics processes and particles'
properties probe our current theory of elementary particles, the so-called Standard Model
(SM). The discovery of the...
Recent detection of gravitational waves from merging black holes and neutron stars opened a
new window for studying the Universe and further accelerated the tremendous progress in
multiwavelength time-domain astronomy. This talk will review exciting new developments in
the quest for uncovering the origin of chemical elements in the Universe and understanding
the birth of neutron stars and...
The COMPASS tokamak, originally constructed and operated at UKAEA in UK, has been
reinstalled at the Institute of Plasma Physics of the CAS in 2009 and experienced a fruitful
decade of scientific exploration. In this contribution, we will summarize the main
achievements, which have contributed to the physics understanding of tokamak plasmas and
development of nuclear fusion related...
Czech Republic is aspirant member of the Facility for Antiproton and Ion Research (FAIR)
since March 2019. Unique new European Large Research Infrastructure FAIR is currently
built up at the campus of German national laboratory for heavy ion research GSI Darmstadt.
It will cover research in nuclear and hadron physics as well as in associated fields. It is
included in the European Strategy...
It is widely known that nucleosynthesis takes place into stars. Element lighter than
Iron and heavier than Lithium (partially produced in primordial nucleosynthesis) are
in fact produced during stellar evolution by means of the interaction between
charged and neutral particles. About charged particles its interactions is strongly
hampered by the presence of the Coulomb barrier – usually...
Abstrakt: Vzdelávanie je procesom sprístupňovania nadobudnutých poznatkov a overených
postupov z vybranej oblasti ľudskej činnosti, ponúkajúcim využívanie a nadväznosť na
existujúcu úroveň vedy, techniky či spoločenských zvyklostí. Kvalitným vzdelávaním nie iba
informujeme o minulosti, ale najmä iniciujeme smerom k budúcnosti. Fyzika, ako veda, má
obrovský vzdelávací potenciál z pohľadu...
Knowledge of experimental activation cross sections is important for creation and evaluation
of evaluated libraries (TENDL) used by various programs for design accelerators, their
components, reactors, but also for nuclear structure study. The proton and deuteron activation
cross sections have been studied at NPI CAS (Nuclear Physics Institute) for many years at
variable energy cyclotron...
Zvyšovanie výpočtového výkonu počítačových komponentov, ktoré je sprevádzané
znižovaním ich cien je predpokladom vzniku nových progresívnych oblastí, ktoré postupne
získavajú na popularite, vďaka čomu získavajú masový rozmer. Tieto nové technológie rýchlo
prenikajú do rôznych oblastí nášho života a školstvo nie je výnimkou. V čase, keď väčšina
žiakov vlastní digitálne zariadenie sa...
Precise nuclear data are of great importance in the design of fusion and ADS devices. The
studies of prompt and delayed gamma rays from (n,g*) reactions bring important knowledge
as it is one of the main sources of nuclear data such as cross-section, nuclear energy levels,
etc.
A central part of the capability is the Cyclotron U-120 and neutron converter coupled to the
collimator. The...
Cieľom príspevku je ponúknuť učiteľom fyziky spôsob ako rozvinúť žiacke predstavy
o tlaku v kvapalinách, o jeho príčine a dôsledkoch. Zaoberáme sa preto chápaním pojmov
tiaž, tiažová sila, gravitačná sila. Venujeme sa tiež pokusu s kvapalinou v beztiažovom stave,
kedy na telesá ponorené v kvapaline nepôsobí vztlaková sila. V príspevku navrhujeme
experiment zameraný na overenie lineárnej...
At the Nuclear Physics Institute at the laboratory of Fast Neutron Generators, a new neutron
collimator was recently constructed. Simultaneously a new neutron converter coupled to the
collimator was constructed and successfully tested last year. Collimated beams of fast
neutrons bringing new experimental possibilities especially for on-beam measurements with
semiconductor detectors....
Experiment je základním prvkem nejen ve fyzice jako vědě, ale také ve výuce fyziky. Ačkoliv
je v poslední době více výzkumné pozornosti věnováno samostatnému experimentování žáků
v rámci badatelské výuky, významnou roli stále ve školách hraje demonstrační experiment.
Na katedře didaktiky fyziky MFF UK má projekt předvádění demonstračních experimentů pro
studenty středních škol tradici více...
It is well known that the radioctive decay can be influenced from external environment [1][2].
However we still don't have a univocal picture that describes these effects. Understanding
how the radioctive decay is influenced in high density environments is useful for different
fields like, for example, the relevant fusion processes in stellar environment [3] or for isotope-
cycling and...
Co zajímá nejmenší "fyziky" z mateřských škol a prvního stupně základních škol, co se jim
líbí a co všechno dokáží, a co na to jejich učitelé? Co vše lze prostřednictvím jednoduchých
fyzikálních pokusů u dětí rozvíjet? Jak fyzika pomáhá spolupráci učitelů z různých typů škol?
Při odpovídání na předchozí otázky vychází autorka ze své mnohaleté zkušenosti se
zprostředkováváním...
The transition metal oxides, with perovskite structure, have been largely studied because these
materials exhibit strong coupling between orbital, electronic, spin and lattice degrees of
freedom. The atomic substitution at the dodecahedral sites in stoichiometric compounds has
been extensively studied and recently, interest has turned on to the effect of the substitution at
the octahedral...
Smíchovská střední průmyslová škola se dlouhodobě snaží o zavádění nových forem výuky,
se kterými souvisí také snaha o status otevřené instituce přístupné všem generacím. Centrem
všeho dění jsou samozřejmě studenti školy, kteří mají možnost se všeobecně rozvíjet, a to
nejen klasicky v hodinách, ale i jako asistenti či vedoucí workshopů pro mateřské a základní
školy a od roku 2015 také pro...
The study of intermetallic compounds has a long history. Rare earth intermetallic
compounds are systematically investigated more than 3 decades already. Polycrystalline
samples (Ce,Gd,Yb)Ni 5 were prepared by different ways, where interesting physical problems
were studied.
In this work we focused on competition between the effect of spin fluctuations and the
possible existence of quantum...
Multiferroic materials exhibiting coupled magnetic and electric orderings are intensely
studied due to an interest in both their fundamental properties and potential applications based
on the magnetoelectric coupling. In general, magnons are collective spin excitations of
various types. In multiferroics, the electric component of the electromagnetic radiation can
excite magnons via the...
Geometrically frustrated lattices play an important role in emergent quantum mechanical
phases, which have been rather well investigated in electronic insulators. A system that
exhibits both lattice frustration and metallic behaviour are the rare-earth (RE) tetraborides
REB 4 . They have a tetragonal structure with magnetic RE ions embedded in boron network
and forming a lattice...
Mikroštruktúra materiálov determinuje aj ich makroskopické fyzikálne vlastnosti. Tie je
nevyhnutné poznať hlavne v prípade ocelí, ktoré sa používajú ako základný materiál pre
konštrukčné prvky jadrových zariadení. Ukazuje sa, že chróm v rôznych zliatinách má
antikorózne vlastnosti kvôli povrchovej segregácii a tvorbe pasivačnej vrstvy. Práve preto sú
ocele s prímesou chrómu vhodným...
In the past two decades Ni-Mn-Ga Heusler alloys have received great attention as these
exhibit magnetic shape memory effects, first described in 1999. Modulated Ni 2 MnGa
martensite has exceptionally low stress for pseudoplastic deformation or structural
reorientation by twinning mediated by highly mobile twinning boundaries [1]. Owing to large
magnetic anisotropy and low twinning stress...
Píšťalky a najmä fujara sú neodmysliteľnou súčasťou slovenskej kultúry a svetového
kultúrneho dedičstva. Najviac osobitými slovenskými píšťalami sú fujara (najdlhší nástroj
tohto typu na svete) a koncovka (píšťala bez dierok). Fujara si získala celosvetovú pozornosť
najmä špecifickou farbou zvuku, koncovka zasa svojou jednoduchou konštrukciou
a spôsobom hry na ňu. Oba tieto nástroje však...
Odklon od využívání fosilních paliv vyžaduje hledání nových nosičů energie, které budou
nezbytné pro dosažení ambiciózního cíle uhlíkově neutrální energetiky. Přestože podíl výroby
elektrické energie z obnovitelných zdrojů, především solární a větrné, neustále roste,
významnější závislost na těchto zdrojích bude spojena s řešením různých problémů,
spojených především s vlivy počasí a...
At RHIC energies, charm quarks are primarily produced in hard partonic scatterings at early
stages of ultra-relativistic heavy-ion collisions. This makes them an ideal probe of the Quark-
Gluon Plasma (QGP) produced in these collisions, since they experience the whole evolution
of the hot and dense medium. STAR is able to study the interactions of charm quarks with the
QGP through direct...
We employed the eye-tracking method (Eyetracker by Tobii, 300 Hz) in order to observe
students’ strategies of choosing an option when they solved multiple-choice tasks focused on
graph slope interpretation. Each student solved 7 multiple-choice tasks focused on graphs in
kinematics. Most tasks were adopted from Beichner’s TUG-K test (Beichner, 1994).
Particularly, they were focused on...
Cílem příspěvku je prezentovat výsledky mezinárodního šetření o existenci a obsahu
překlenovacích kurzů pro absolventy středních škol, kteří nastupují do 1. ročníku studia
přírodovědných předmětů na vysokých školách. Byli dotazování jak studenti, tak i
vysokoškolští pedagogové, zda jsou takovéto kurzy na vysokých školách nabízeny, zda
studenti tyto kurzy navštěvují, popř. zda by byl o...
It has been established that the Quark-Gluon Plasma (QGP), an exotic state
of deconfined matter, is created in high-energy heavy-ion collisions. Jets are a
very important probe of this hot and dense nuclear matter, since they emerge
from the fragmentation of hard-scattered partons (quarks and gluons) that are
created during the early stages of the collisions. Therefore, measurements...
QCD jets are modified ("quenched") by their interactions with the quark-gluon plasma (QGP)
formed in high-energy nuclear collisions. The measurement of jet quenching in small collision
systems can tell us about the limits of QGP formation and the nature of equilibration in QCD,
but to date no significant jet quenching has been observed in small systems. In this talk, the
ALICE...
Konštruktivistické prístupy, ktoré sa v súčasnosti uplatňujú vo vzdelávaní v podobe
bádateľsky orientovanej výučby, zdôrazňujú okrem rozvíjania porozumenia aj rozvoj
zručností a spôsobilostí súvisiacich s činnosťami, ktoré vedú ku konštrukcii poznatkov. Počas
prípravy študentov učiteľstva fyziky sa však často stretávame so situáciou, kedy študent
uprednostňuje vyučovacie stratégie, ktorými...
Jets of collimated particles arising from hard scattered partons have been studied extensively
in hadron collisions. Jets serve a multitude of purposes as they are utilized in fundamental
studies of the Standard Model (SM) and in searches for new particles. Recently, studies of jet
interaction with the quark-gluon plasma (QGP) created in high energy heavy ion collisions are
of growing...
V poslední době se i ve vysokoškolské výuce, zejména v úvodních kurzech během prvních let
studia, objevuje posun od tradičně pojaté výuky k aktivizujícím výukovým formám. Jejich
prostřednictvím se prohlubuje konceptuální pochopení základních myšlenek, které se tak
vzájemně doplňuje s řemeslným zvládnutím konkrétních technik řešení úloh typických pro
dané fyzikální téma. Výzkumy prováděné...
Heavy-ion collisions allow to recreate conditions present in the universe shortly after the Big
Bang when the quark-gluon plasma can be formed. The properties of such plasma can be
studied using Upsilon mesons. Each of Upsilon states is expected to dissociate at a different
temperature reached in the plasma, through Debye-like screening of color charges. Thus, their
production yields are...
Lab rats and rabbits are irrepleceable models for study of the ortopedic pathologies.
Traditional analysis of these pathologies is based on postmortem histological analysis or X-
ray or invasive sampling, however modern monitoring of orthopedic pathology and
regeneration needs the smart and noninvasive methods for quantification of the motility of
the limbs and organism. Advances in...
V súčasnosti častokrát skloňované problémy s prírodovedným vzdelávaním sú v centre
pozornosti národného projektu IT Akadémia, ktorého hlavným cieľom je vytvorenie modelu
vzdelávania pre aktuálne a perspektívne potreby vedomostnej spoločnosti a trhu práce so
zameraním na informatiku a digitálne technológie. V rámci príspevku predstavíme dva
kľúčové ciele projektu: inovácia vzdelávania...
Nepretržitý pokrok v oblasti magneticky mäkkých materiálov prináša nové možnosti ich
využitia v modernej elektrotechnike a elektronike. Cieľom hľadania progresívnych materiálov
je snaha o zníženie ekonomických nákladov na ich výrobu a prevádzku z nich zhotovených
výrobkov v priemyselných aplikáciách. Magneticky mäkké kompozity (MMK) vyrobené
práškovou metalurgiou otvárajú nové možnosti pri...
Predkladaný príspevok je venovaný pedagogicko-psychologickej téme záujmu, ako jedného
z významných činiteľov zohrávajúcich dôležitú úlohu v procese samostatného žiackeho
bádania a učenia sa. Autori príspevku sústreďujú svoju pozornosť na záujem žiakov o
predmet školskej fyziky. Dôraz pritom kladú na poznávací záujem. Hlavným cieľom
príspevku je zistiť prítomnosť poznávacieho záujmu...
The low-temperature electron-hole plasma may undergo phase transition to the liquid state:
the electron-hole liquid (EHL). The transition is allowed in dense plasma below critical
temperature T C and it exists only in the thermodynamic limit, i.e. when the lifetime of the
electron-hole system is long enough to reach the thermal equilibrium. For that reason, the
macroscopic and relatively...
Človek je spoločenská bytosť a integrálnou súčasťou spoločenského života je aj komunikácia.
Pri komunikácií musíme často zdôvodňovať svoje tvrdenia, presviedčať iných o ich
pravdivosti – argumentovať. Schopnosť argumentovať však nie je schopnosť, ktorá je človeku
daná pri narodení. Je však možné ju rozvíjať a zlepšovať napríklad tým, že žiaci počas hodín
vyjadrujú svoje názory pri riešení...
Hodnotenie, ako súčasť výchovno-vzdelávacieho procesu, je v poslednej dobe značne
diskutovanou témou medzi odborníkmi v didaktike, učiteľmi, žiakmi, rodičmi ale i v celej
spoločnosti. Diskutovanou témou je najmä úloha hodnotenia, jeho funkcie a postavenie vo
výchovno-vzdelávacom procese. Taktiež sa vedú úvahy, či je hodnotenie v podobe, akej sa
realizuje, objektívne a naozaj posudzuje...
Nitride semiconductor heterostructures are widely used for light-emitting, high-power and
high-frequency applications. But InGaN/GaN multiple quantum well (QW) structures are also
potential candidates for scintillation detectors. This application needs completely different
design of the heterostructure in comparison with LED one. It opens new problems that have
not been solved yet. Main...
Cílem výzkumu, o jehož části pojednává tento příspěvek, je zjistit představy zainteresovaných
aktérů o fyzikálním kurikulu. Mezi tyto aktéry patří mimo jiné fyzikové–vědci, další
přírodovědci, didaktikové fyziky a učitelé fyziky. Na základě sběru a analýzy jejich představ
budou formulovány podněty k proměně současného kurikula fyziky pro základní a střední
školy.
Cílem příspěvku je...
The present work deals with the exactly solvable spin-1/2 Ising-Heisenberg model on an
infinite but regular two-dimensional lattice composed of identical inter-connected bipyramidal
plaquettes with the aim to clarify a bipartite entanglement between the Heisenberg spins at
zero as well as finite temperatures. The quantity called concurrence is used as an indicator for
determining a...
The Brownian motion of a particle in a bath of other particles is effectively described by the
generalized Langevin equation (GLE). Following Kubo, it is usually assumed that if external
forces act on the system, they do not affect the thermal force and the memory function that
enter the GLE. The action of such forces is restricted to the Brownian particle (BP), leaving
the bath particles...
The Brownian motion of a particle immersed in a bath of charged particles is considered when
the system is placed in a magnetic field. The widely accepted Caldeira-Legget particle-bath
model is modified so that not only the charged Brownian particle (BP) but also the bath
particles respond to the external field. For stationary systems, two equations for the BP
motion across the field are...
The Heusler Ni 2 Mn 1+x Sn 1-x alloys exhibit structural martensitic transformation from cubic
(austenite) into orthorhombic (martensite) phase in a narrow composition range, 0,4 ≤ x ≤ 0,6,
only. The transformation is accompanied by a significant changes of volume, magnetization
and by large anomalies in transport properties. We have studied forced volume magneto-
striction, Joulian...
Sbírka řešených úloh z fyziky a Sbírka fyzikálních pokusů vznikají na Katedře didaktiky
fyziky MFF UK. Jedná se o podpůrné materiály pro studenty a učitele základních, středních
i vysokých škol.
Sbírka řešených úloh z fyziky je vyvíjena již 14 let a obsahuje přes 900 úloh v češtině. Je
primárně určena vysokoškolským studentům a žákům středních škol, lze v ní ale nalézt
i úlohy na úrovni...
Metallic glasses are still attracting the interest of researchers namely for their very good soft
magnetic properties. With the aim to enhance their practical applications, new compositions
are continuously scrutinized. Here, we present Mössbauer spectrometry study of a novel
Fe 51 Co 12 Si 16 B 8 Mo 5 P 8 metallic glass prepared in a form of ribbons by conventional method of
planar flow...
Polyaniline (PANI) is a material known for its high conductivity and also huge range of
obtainable conductivities. In general, three types of charge carriers are considered in PANI
salt, namely holes, polarons and protons. Many authors attribute the high conductivity of acid
doped PANI to polarons [1-3]. We show that conductivity of polarons might not be
necessarily the prevailing...
If we put a several tens of microns thin sample of nematic liquid crystal with planar alignment
of molecules with respect to the LC cell surface in between two crossed plane polarizers,
illuminate it by white light and rotate appropriately, then using a fiber optic spectrometer we
can observe a quasi-periodic spectral distribution of intensity of light behind the output
polarizer. The...
Lawsonite [CaAl2Si2O7(OH)2·H2O] is an uncommon mineral found in metamorphic rocks,
occurring at subduction zones, supposedly at depths of up to 250 km. It contains 11.5 wt%
water in its crystal structure. At room temperature, it is orthorhombic, crystallizing in the
Cmcm space group. Its structure contains a silicate tetrahedra framework with four formulas
in the unit cell. Each chemical...
Thermoplastic starch, a group of starch-based materials, has often been under review because
it can be used as low-cost bioplastics. Native starch is usually processed under the action of
high temperature and shear stress with addition of plasticizers such as low molecular weight
polyols and/or amide-containing molecules to obtain a moldable thermoplastic material. Such
materials are...
STEM vzdelávanie zamerané na Science, Technology, Engineering a Mathematics zahŕňa
v sebe prípravu vysokoškolsky vzdelaného absolventa technickej univerzity, ktorý v priebehu
prípravy získal zručnosti zo všetkých spomínaných oblastí. Podľa Bloomovej taxonómie
poznávacích cieľov takéto vzdelávanie je realizované na vyšších stupňoch, ako je analýza,
aplikácia a hodnotiace posúdenie....
V lednu 1956 bylo Československo přizváno k účasti na založení ústavu pro jaderný, který
měl být obdobou Laboratoře Evropské organizace pro jaderný výzkum (CERN) v Ženevě pro
země tzv. lidové demokracie. Československé stranické a vládní orgány nabídku přijaly.
Na konferenci o ústavu, která se konala ve dnech 20.–26. března 1956 v Moskvě, byla
československou vládou vyslána sedmičlenná...
Tokamak COMPASS je vybaven dvěma sadami diagnostik, které jsou rutině využívány
k počítání tomografických inverzí. Jedná se o polovodičové diody, které slouží buď jako
bolometry (měří celkový vyzářený výkon), nebo jsou vybaveny beryliovým filtrem a měří
měkké rentgenové záření.
V důsledku omezení pozorovacích úhlů je tomografická inverze na tokamacích nedostatečně
určená, a proto se...
The uranium based intermetallics are intensively studied because of dual character of uranium
5f electrons. Unique coexistence of ferromagnetism and superconductivity has been revealed
in URhGe and UCoGe crystalizing in the orthorhombic TiNiSi-type structure. Since UCoGe
(T C =2.5 K) is very close to magnetic instability, it is a candidate to observe vanishing of
ferromagnetic order and...
Dust grains in the Martial dust storms or dust devils may be electrically charged by
triboelectric effects and laboratory experiments show that under specific conditions electric
discharges might occur in the dusty Martian atmosphere. Remote measurements from the
Earth using a 34-m Deep Space Network antenna have shown a non-thermal component of
electromagnetic radiation from Mars which...
Atomic Force Microscopy (AFM) is a powerful imaging technique which provides very high-resolution images and topological data in scales of nanometers. The quality of the obtained data is determined by quality of used AFM tip and fine adjustment of measuring parameters and settings of the machine. The measurement becomes more challenging if the AFM probe is about to approach a soft and elastic...
Kvarkonia jsou dúležitou sondou k vyšetřování vlastností kvark-gluonového plasmatu.
Proton-protonové srážky jsou nezbytným prostředkem k ustanovení základních vlastností,
které slouží ke studiu kvarkonií v proton-jaderných a jádro-jaderných srážek. Tento poster
prezentuje základní charakteristiky Upsilon mezonů zjištěné pomocí Monte Carlo generátorů
v proton-protonových srážkách při √ sNN...
Al-Li based alloys of AA2195 type are designed mainly for aerospace applications. They
exhibit a very high strength due to a presence of strengthening precipitates of a nanometric
size. However, materials prepared by a conventional direct-chill casting and following rolling
exhibit strong crystallographic texture and inhomogeneous mechanical properties. This
inconvenient behavior could be...
The Waves instrument onboard the Juno spacecraft recorded numerous cases of dispersed
electromagnetic waves generated by Jovian lightning. These waves, also known as whistlers,
propagated through ionospheric and magnetospheric plasmas before their detection by Juno
during its close approaches to Jupiter. We present observations of nearly five thousand low-
dispersion lightning whistlers...
Nitride semiconductors became the second most important semiconductor material after
silicon in the last two decades. Many daily used devices, such as blue light emitting diodes or
high electron mobility transistors in electronic devices, are based on nitride semiconductors.
Despite the nitride devices mass production, there are many open questions and not well
understood phenomena which...
One of the approaches to investigate the equation-of-state of dense nuclear matter is the study
of the short-range correlations of nucleons in nuclei. Short-range correlations have densities
comparable to the density in the center of a nucleon and they can be considered as the drops
of cold dense nuclear matter. Dp elastic and dp breakup processes are investigated at Internal
Target...
Nanoparticles of hexagonal phase in bcc-Ti(Mo) single crystals ( phase) occur due to a
diffusionless athermal to transformation and they grow during follow-up ageing at
elevated temperatures, while the alloying atoms (Mo in our case) are expelled from the
nanoparticle volumes. We used anomalous x-ray diffraction for the study of local chemical
composition of growing particles and...
The idea of controlling the magnetic ground state of a spin-1 one-dimensional
antiferromagnetic (1d AFM) quantum magnets has long been of interest to physicists. In the
study of anisotropic 1d AFM systems based on Ni 2+ compounds, a series of topologically
protected quantum phases was observed, one of these phases is the topologically protected
Haldane phase [1, 2]. The magnetic ground...
Current work is focused on the lattice subsystem of Cu(en)Cl 2 , Cu(tn)Cl 2 and
Cu(en)(H 2 O) 2 SO 4 (en = C 2 H 8 N 2 , tn = C 3 H 10 N 2 ), quasi-two-dimensional quantum magnets with
one-dimensional polymeric structure. Magnetic layers were described within spin = 1/2
Heisenberg models on the rectangular and zig-zag-square lattice with nearest-neighbor
couplings J 1 > J 2 . The...
Small-scale thin films are frequently used in microelectronic devices and micro-electro-
mechanical systems where they are commonly subjected to high strains during their dynamic
motion. However, mechanical behavior of thin films significantly differs from the behavior
observed in bulk materials. To understand the size dependent properties of deformation
mechanisms, characterization of the...
Bonding of aluminium and steel into one single material – an aluminium-steel clad –
represents an excellent composite material, which provides high potential for applications in
automobile industry by combination of properties of respective materials – high stiffness and
strength of steel and durability, corrosion resistance, thermal capacity and high specific
strength of aluminium....
Twin-roll casting of AA8079 aluminum sheets creates non-equilibrium structure as a result of
high solidification rates. Homogenization treatments consisting of an exposure of the as-cast
material to high temperatures close to the melting point result in a redistribution of solute
atoms and a formation of a more stable structure. Newly formed equilibrium particles have
different...
The usual interband transitions S0–S0, S0–S1, S0–S2 can be clearly identified in the recently published photoluminescence measurements on P3HT layers. However, in many cases the spectra are characterized by weaker ripples besides these main features. We point out their possible interpretation by means of the H and J aggregates theory proposed by Spano (F. C. Spano, J. Chem. Phys. 122,...
One of the fundamental features of nanotechnology is that properties of a certain material can
be changed just by varying its shape and size. This exactly is the case for the two types of
gold nanostructures in our study, where luminescent gold nanoclusters (AuNCs) benefit from
the presence of plasmonic gold nanorods (AuNRs). Despite the limited number of atoms,
AuNRs with characteristic...
Laserové systémy prošly od svého objevení v roce 1960 dlouhou cestu a v posledních letech
se stávají stále častěji běžně využívaným pracovním nástrojem. Centrum HiLASE
Fyzikálního ústavu se od svého vzniku zaměřuje na vývoj špičkových, zejmna pulsních,
diodově buzených pevnolátkových laserů pro moderní průmyslové aplikace. Takové lasery
s vysokou účinností, středním výkonem až 1 kW a dobou...
Štúdium dielektrických parametrov vedie k lepšiemu porozumeniu polarizačných
a relaxačných javov v nových materiáloch. Táto štúdia je zameraná na mnohostenné
karbónové nanorúrky funkcionalizované magnetickými nanočasticami. Pomocou dielektrickej
spektroskopie sa študoval vplyv elektrického poľa na zmeny dielektrických parametrov
i štruktúrneho usporiadania MWCNT/Fe 3 O 4 . Frekvenčná...
This paper focuses on quantum dots (QDs) embedded inside semiconductor heterostructures
prepared by Metalorganic Vapor Phase Epitaxy (MOVPE) technology and is based on our
contribution in [1].
Light emission from atoms/molecules in a glass matrix or in gas is strongly monochromatic.
Semiconductor direct-bandgap materials have much higher energy conversion efficiency than
the other light...
The contribution focuses on a new plasma laboratory, currently in commissioning phase. Its
aim is to provide doctoral and undergraduate students as well as non-fusion experts with
hands-on experience and support for their experimental research relevant to modern fusion
technology. The laboratory consists of four main sections: Electric and magnetic fields,
Plasma, Optics, and the GOLEM...
Thin MoS 2 layers grown by sulfurisation of Mo films can be aligned horizontally or vertically
depending on the initial Mo thickness. So far, the vertical alignment of MoS 2 layers has been
detected by TEM measurements. However, TEM provides information only from a very
limited area of the sample and requires time consuming and laborious sample preparation.
Alternatively, grazing incidence...
Turbulence is one of the most fascinating phenomena in nature existing from Ångström
length-scales (quantized vortices in superfluid helium [La Mantia et al. 2016]) up to galactic
scales [Vatistas 2010]. One of the main features of turbulence is the presence of interacting
vortices of various strengths sizes and orientations. But the present description of turbulence
is based on...
The physical and chemical properties of materials tested on the macro- or nano-scale may
differ dramatically. For example, when measuring the Young's modulus of elasticity, we
assume an “infinite” depth of material, which is not fulfilled especially when the Young’s
modulus is measured at the nano-scale. Another example, the interaction of nanomaterials
with biological environment and...
Low dimensional materials offer very interesting material and physical properties due to
reduced dimensionality. At present, 2D materials are the focus of attention. However, 1D
systems often show far more exotic features, such as Tomanaga-Luttinger liquid, Peierls
distortion, etc.. In this talk, we will present -conjugated molecular chains of distinct
topological classes formed on...
V posledných rokoch vzrástol význam syntézy konjugovaných kopolymérov spájajúcich v
jednej molekule rôzne monoméry. Takéto materiály nachádzajú široké uplatnenie v
mikroelektronike aj vo fotovoltike, keďže ich cielaná syntéza umožňuje nielen vhodné
nastavenie šírky zakázaného pásu, ale aj zvýšenie účinnosti konverzie slnečného žiarenia na
elektrickú energiu spojením monomérov s dierovou a...
The new polycrystalline intermetallic compound Gd 3 Ni 2 In 4 has been prepared. We have
investigated the structural, magnetic, magnetocaloric, thermodynamic and transport
properties. X-ray powder diffraction pattern displays that Gd 3 Ni 2 In 4 crystallizes in hexagonal
Lu 3 Co 2 In 4 – type of crystal structure. The presence of two magnetic transitions,
antiferromagnetic T N = 21 K and...
We present unusual properties of the commercial quartz tuning forks (QTFs) operating at
resonance frequencies of 32 kHz, 77 kHz and 100 kHz at temperature range below 1K and in
high magnetic fields up to 7.5 T. We show that in millikelvin temperature range, the quartz
tuning forks exhibit the property of the coherent oscillations. These are manifested as a
temperature-dependent, extremely...
We present analysis of microscopic origin of magneto-optical spectra from the electronic
structure of bcc Fe. The magneto-optical (MO) permittivity spectra are obtained by the
WIEN2k code and compared to the corresponding experimental MO Kerr effect spectra. The
ab-initio spectra are given by the Kubo formula, i.e., as a result of summation over all pairs of
electronic bands and...
Simple examples that the direction of the momentum, defined by its spectral support in a
given state, and the direction of the probability flux may be locally uncorrelated in 1+1
dimensional space-time are given for the Schrödinger and the Dirac particle with non-zero
mass. For the zero-mass Dirac particle, they are always correlated.
Jednoduché příklady ukazují, že směr...
The Ni 1.92 Mn 1.56 Sn 0.52 belongs to a family of Heusler alloys with peculiar magnetic, structural
and transport properties that can be potentially useful for applications. They show structural
transition from high temperature cubic austenite (A) to low temperature orthorhombic
martensite (M) with significant changes of volume, magnetization, resistivity and Hall effect.
We have...
The future experimental facility EIC (Electron-Ion Collider) that will be built in Brookhaven
National Laboratory in the USA introduces new opportunities for precise study in high energy
nuclear physics. This contribution is an overview of the author’s research related to this topic.
Particularly, in this contribution, we focus on topics as nuclear shadowing, quarkonia wave
function study,...
We report that this alloy has been formed in three phases Dy 5 Si 3 , Dy 3 Co 2.2 Si 1.8 , and Dy 3 Co with
four successive magnetic transitions. The important role in the magnetic behavior plays
competing ferromagnetic and antiferromagnetic interactions in the alloy. The number of
successive magnetic transitions together with competing magnetic interactions exhibit
broadened...
With an aim of promoting open-source software and text files for data storage and processing,
the author presents a program [1] that attempts to resolve the less-than ideal situation in this
field.
The usual approach is to either load the data into a point-and-click application for scientific
plotting, or learn basics of programming and type the commands in a scientific math...
Extraction of the multi-TeV proton and lead LHC beams with a bent crystal or by using an
internal gas target allows one to perform the most energetic fixed-target experiment ever. pp,
and pA collisions at collision energy of 115 GeV and Pbp and PbA collisions at 72 GeV can
be studied with high precision and modern techniques over a broad rapidity range. Using the
LHCb and ALICE detectors...
Development of a new material with required properties is a very complex task. Theoretical
models for growth procedure are usually not available, at least at the beginning. Therefore,
many attempts are made to achieve required properties of the material and many
characterization datasets are obtained. However, the way how the physical properties of the
material are affected by the growth...
The ALICE Inner Tracking System detector is undergoing a major upgrade in order to cope
with the increased data rates and to meet the requirements as set out by the physics goals of
the experiment after Long Shutdown 2. The new ITS will be completely made up of ALPIDE
monolithic active pixel sensors based on a CMOS 180nm process. A single sensor measures
15mm x 30mm and contains half a...
We describe macroscopic defects on InGaN/GaN multiple quantum well structures caused by
accidental contamination with dust particles during the metalorganic vapour phase epitaxy.
Gallium nitride and InGaN/GaN heterostructures are promising materials for many
optoelectronic devices, such as light emitters, high-power and high-frequency electronics,
detectors of ionizing radiation,...
The properties of the heavy fermion compound Ce 3 PtIn 11 are rather enigmatic. Not only the
compound possesses two inequivalent Ce-sites but at ambient pressure it exhibits two
successive antiferromagnetic (AFM) transitions at T 1 = 2.2K and T N = 2K, respectively [1].
Upon further cooling superconductivity is found with T c = 0.32K. Entropy analysis
conjectured the idea that the Ce2-ions...
Charm quarks are mostly produced in hard partonic scattering processes in the early stages of
a heavy-ion collision, before the quark-gluon plasma (QGP) is formed. Because of their large
mass the production cross section can be calculated using perturbative quantum
chromodynamics down to zero transverse momentum. Therefore, they are ideal probes of the
properties of this hot, dense, and...
The discovery of graphene – the archetype two-dimensional (2D) system, stimulated the
frantic pace of research in the area of 2D materials (2DM). The rapid progress of the field,
particularly in the growth technologies, is enabling expanding the research interests in other
2DM with outstanding optical, transport, magnetic and other properties giving rise to a
plethora of tailored...
Surprise for the persistent individuals - goodbye drink
(foyer of building A - behind the lecture room T1)
Why are the III-nitride semiconductors so unique that they became the second most important
semiconductor material after silicon? Why it was so difficult to prepare high quality nitride
layers? It was so difficult that scientist, which have partly solved this problem were five years
ago awarded by Nobel Prize. What are the most perspective applications for nitrides? What
problems have to...
