2026-01-24
00:12 |
Preparation and analysis of multilayer metal- dielectric systems by PVD methods
Lis, Jáchym ; Skočdopole, J. ; Bulíř, Jiří ; Kalvoda, L. ; Fekete, Ladislav
To develop the use of hydrogen technologies in the energy sector, it is necessary to ensure their safety by developing high-quality hydrogen sensors. In this work, two principles of optical sensors exploiting metal-dielectric interface phenomena in multilayer thin film structures are investigated, specifically the combination of a thin silver layer with a very thin palladium layer for excitation of the surface plasmon-polariton and the combination of silver, a dielectric intermediate layer and a very thin palladium layer for excitation of the waveguide mode. The samples were prepared by Magnetron Sputtering and Ionized Jet Deposition methods. The analysis of the samples was carried out using ellipsometry, Attenuated Total Reflection method, atomic force microscopy and computer simulations.
Úplný záznam
|
2026-01-24
00:12 |
Elektrochemická vizualizace otisku prstu nanesením polymerního filmu – CM VaVaI č.159
Festová, S. ; Broncová, G. ; Hlavín, P. ; Novotný, Michal
Vytvořená certifikovaná metodika zviditelnění daktyloskopických otisků je založena na depozici polymerního filmu poly(neutrální červeni) (PNR) na mosazné substráty – nábojnice/mince s naneseným daktyloskopickým otiskem za specifických podmínek daných optimalizací metody cyklické voltametrie v elektrochemické cele. Do cely jsou umístěny tři elektrody. Na pracovní elektrodu, kterou tvoří uchycená nábojnice/mince, je aplikován cyklicky měnící se potenciál v určitých potenciálových mezích tak, aby došlo k depozici (nanesení) filmu PNR na povrch nábojnice/mince a byl zviditelněn daktyloskopický otisk. Optimalizované parametry jsou potenciálové rozmezí –200 až 500 mV oproti referentní argentchloridové elektrodě, počet cyklů 5 až 8 a skenovací rychlost 50 mV/s.
Úplný záznam
|
2025-12-15
16:33 |
Úplný záznam
|
2025-12-15
16:33 |
ECLC2025: Book of Abstracts of the 17th European Conference on Liquid Crystals
Bubnov, Alexej ; Kohout, M. ; Novotná, Vladimíra
This is the Book of Abstracts for the 17th European Conference on Liquid Crystals (ECLC2025 conference) held in Prague (Czech Republic) on June 1-6, 2025. This is the major European conference on liquid crystals, self-assembled materials and related soft matt subjects. At the ECLC2025 conference there were about 200 participants from 30 countries delivered 4 plenary lectures, 28 invited lectures, 61 oral contributions, 12 short oral contributions: 93 posters were presented during two poster sessions.
Úplný záznam
|
2025-08-31
00:00 |
Comparison of Lu.sub.3./sub.Al.sub.5./sub.O.sub.12./sub.:Ce(Er) bulk and nano single crystals
John, David ; Volf, Jakub ; Bartosiewicz, Karol ; Horiai, T. ; Kamada, K. ; Yoshikawa, A. ; Remeš, Zdeněk ; Landová, Lucie ; Ledoux, G. ; Houel, J. ; Prokhorov, Andriy ; Buryi, M.
Lutetium aluminum garnet (LuAG) is a crystal well known for being extraordinarily useful for building highly efficient laser devices or ionizing radiation detectors. To design the most favourable physical properties, different dopants and synthesis methods are constantly developed, primarily focused on the advantages of single crystals. However, the downscaling of the luminescent materials to nanosize also creates additional benefits of increased surface to volume ratio and thus, the efficiency of luminescence or doping can be improved. Therefore, the aim of this work is to compare the single crystals and nanogarnets under the influence of Ce and Er doping. Optical properties of the garnet single crystals are very well known while the nanocrystals should have been studied first.
Úplný záznam
|
2025-06-08
00:00 |
Finite element analysis of nanoindentation pile-up and correction of projected contact area
Kovář, J. ; Fuis, V. ; Čtvrtlík, Radim ; Tomáštík, Jan
This paper deals with the pile-up phenomenon that can occur during nanoindentation. Finite Element (FE) simulation of X5CrNiCuNb16-4 steel nanoindentation with pyramidal Berkovich indenter was done, and stress and strain beneath the indenter leading to pile-up behavior were analyzed in detail. Pile-up also influences the projected contact area, which should be corrected to include the pile-up into the Oliver-Pharr analysis. Accurate calculation of the projected contact area requires knowledge of its boundary. Few methods of boundary approximation were used, including approximation by the triangle and the semi-ellipse. For more precise approximation, the expression for parabolical approximation was derived. These methods were compared with the projected contact area calculated by finite element method. The most precise results were obtained using semi-elliptical and parabolical correction, which can be used for the determination of the projected contact area and its boundary.
Úplný záznam
|
2025-05-03
00:00 |
Optical spectra of thin intrinsic and Al doped nanocrystalline zno thin layers deposited by pulsed laser deposition on fused silica glass substrates
Remeš, Zdeněk ; Neykova, Neda ; Jain, N. ; Sharma, K.R. ; Holovský, Jakub ; Ukraintsev, E. ; Míčová, J. ; Hsu, S.S.
Zinc oxide (ZnO) is a low-cost and environmentally friendly material with unique optical properties and a variety of nano and microstructures imposing challenges for energy conversion, scintillators, photocatalytic wastewater treatment, electrochemical energy storage, or sensing applications. In this work, the nominally undoped and Al-doped nanocrystalline ZnO thin layers were pulsed laser deposited (PLD) on fused silica glass. The samples were characterized by photothermal deflection (PDS) and photoluminescence (PLS) spectroscopy. Excitons were observed at low temperature in both samples at about 3.4 eV. The intrinsic samples show the red PL in near infrared region at about 1.9 eV related to zinc vacancies. The results show that optical properties can be evaluated from optical spectra of very thin nanocrystalline ZnO layers with the thickness below 100 nm.
Úplný záznam
|
2025-05-03
00:00 |
Wet chemistry treatment and surface modification of recycled glass particles for sustainable construction applications
Babčenko, Oleg ; Beranová, Klára ; Remeš, Zdeněk ; Kolářová, Kateřina ; Lörinc, Jakub ; Volf, Jakub ; Prošek, Z. ; Tesárek, P.
The recycled glass particles obtained from the commercial source were treated by wet chemistry (different pH). The resulting changes in glass particle properties were analyzed using microscopic and spectroscopic techniques. Changes in the concentrations of Mg, Al, Ca and Na near the particle surfaces were detected, indicating potential elements release. It is proposed that observed changes in the subsurface region can be important for the calcium-silicate-hydrate formation in concrete-based constructions. The study findings will be helpful in the explanation of processes at interfacial transition zones in waste glass containing concrete-based materials.
Úplný záznam
|
2025-05-03
00:00 |
Metallic and semiconductor nanoparticles integrated into thin layers of hydrogenated amorphous silicon or silicon carbide
Stuchlík, Jiří ; Kupčík, Jaroslav ; Čermák, Jan ; Stuchlíková, The-Ha ; Remeš, Zdeněk
The combination of PECVD - plasma enhanced chemical vapor deposition and VE - vacuum evaporation at one vacuum chamber is in situ method how to integrate semiconductor (Ge) and metallic (Sn) nanoparticles into amorphous hydrogenated thin films and their structures on the base of a-Si:H or a-SiC:H. In this work we focus our effort to deposit a-SiC:H thin films from monomethylsilane (MMS = SiH3-CH3) diluted by hydrogen in the ratio 2/100 sccm. The Ge evaporates at vacuum higher than 2E-5 Pa. The TEM - transmission electron microscopy and AFM - atomic force microscopy are used for microscopical characterization of thin films while PDS - photothermal deflection spectroscopy and PL – photoluminescence spectroscopy are used for their spectroscopical characterization.
Úplný záznam
|
2025-05-03
00:00 |
Nanocomposites of ZnO-decorated HPHT Nanodiamond as a perspective green photocatalysts
Mičová, J. ; Košutová, T. ; Jerigová, M. ; Remeš, Zdeněk
Electrical and optical properties of zinc oxide, in particular the relatively wide direct band gap of ~3.3 eV predetermines ZnO as a photocatalytic material at room temperature. ZnO itself is non-toxic and the hydrothermal growth method we use to prepare its nanostructures is environmentally friendly. These facts contribute to the attractiveness of this material. Recently, we have focused on studying the influence of doping or of plasma surface treatment on the photocatalytic efficiency of ZnO. However, the main disadvantages are the high recombination rate of charge carriers and the poor use of visible light. The solution is the use of ZnO as part of nanocomposites. In the past, ZnO-detonation nanodiamons (DND) composites were studied. The disadvantage of DND is the formation of clusters of different sizes, therefore we focused our attention on the use of HPHT nanodiamonds (NDs). We modified the surface of commercial HPHT NDs by oxidation in order to increase the concentration of hydroxyl-, carbonyl- and carboxyl- functional groups. The resulting ZnO-HPHT NDs composites were synthesized using a dehydration-condensation process between oxygen-containing functional groups on the NDs surface and hydroxyl groups on the ZnO surface. The prepared nanocomposites were characterized by SEM, AFM, FTIR and PL and tested by photocatalytic dye degradation.
Úplný záznam
|
|
|
|
host ::
