Number of found documents: 14683
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Correlated microscopy of electronic and material properties of graphene grown on diamond thin films
Rezek, Bohuslav; Čermák, Jan; Varga, Marián; Tulic, S.; Skákalová, V.; Waitz, T.; Kromka, Alexander
2017 - English
In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into formation and properties of GoD. The diamond films are coated by a nm thin sputtered Ni layer and heated to 900°C in a forming gas atmosphere (H2/Ar) to initiate catalytic thermal CVD process. The samples are cleaned from residual Ni after the growth process. We employ scanning electron microscopy, Raman micro-spectroscopy and Kelvin probe force microscopy to correlate material, structural, and electronic properties of graphene on diamond. We show how grain size and grain boundaries influence graphene growth and material and electronic properties. For instance we show that the grain boundaries (with non-diamond carbon phases) in diamond films have an important role. They influence the electronic properties and they are beneficial for forming graphene on diamond higher quality. Keywords: graphene; diamond; microscopy; micro-spectroscopy; electronic properties Available at various institutes of the ASCR
Correlated microscopy of electronic and material properties of graphene grown on diamond thin films

In this work we compare growth of graphene on diamond thin films that enable large area processing. We use films with different crystal size and surface roughness to obtain deeper insight into ...

Rezek, Bohuslav; Čermák, Jan; Varga, Marián; Tulic, S.; Skákalová, V.; Waitz, T.; Kromka, Alexander
Fyzikální ústav, 2017

Chemical and microstructural characterization of the render, sampled from Gloriette, the US Embassy in Prague 1
Slížková, Zuzana; Frankeová, Dita; Viani, Alberto; Hauková, Petra; Koudelková, Veronika; Svoboda, Milan
2017 - English
The aim of the work was to analyze the mortar taken from the Gloriette (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in HCl to determine the mixing ratio. Keywords: survey; material characterization; chemical composition; binder and aggregate characterization Available at various institutes of the ASCR
Chemical and microstructural characterization of the render, sampled from Gloriette, the US Embassy in Prague 1

The aim of the work was to analyze the mortar taken from the Gloriette (US Embassy, Prague 1). Analyzes were performed for the binder and filler characterization and the sample was also dissolved in ...

Slížková, Zuzana; Frankeová, Dita; Viani, Alberto; Hauková, Petra; Koudelková, Veronika; Svoboda, Milan
Ústav teoretické a aplikované mechaniky, 2017

Souhrnný report výsledků smluvního výzkumu mezi FZU AV ČR, v.v. i. a HVM Plasma s.r.o. za rok 2016
Mates, Tomáš; Fejfar, Antonín; Ledinský, Martin; Vetushka, Aliaksi; Pikna, Peter; Bauerová, Pavla
2017 - Czech
Několika diagnostickými metodami byly zkoumány vzorky ochranných vrstev na bázi DLC (Diamond-like-Carbon) na různých substrátech (testovací tělíska i reálné součástky). Pomocí Ramanovské spektroskopie byly vyhodnocovány vazby ve vzorcích pro bližší určení strukturních variací a povrchových modifikací, a to jak pro čerstvě připravené vzorky, tak zejména pro vzorky které prošly různými zátěžovými testy.\nSkenovacím elektronovým mikroskopem (SEM) byla zkoumána povrchová struktura vrstev v různých místech vzorků a vyhledávána vhodná testovací místa pro následnou analýzu pomocí Mikroskopu atomárních sil (AFM). Mikroskopem AFM ve speciálních režimech byly měřeny mapy lokálních mechanických vlastností (tření, adheze hrotu, disipace energie, atd.). Na vybraném vzorku byla metodou Focussed Ion Beam (FIB) analyzována struktura průřezu vzorku a dále bylo zdokumentováno prvkové složení v různých tloušťkách vrstvy metodou Energy-dispersive X-ray Spectroscopy (EDS).\n Samples of protective layers based on DLC (Diamond-like-Carbon) on different substrates (test bodies and real components) were studied by several diagnostic methods.\nRaman spectroscopy was used for the detection of bindings in order to specify the structural variations, surface modifications both for as-deposited samples and particularly for samples that underwent different stress tests.\nScanning Electron Microscope (SEM) was used to examine the surface structure of layers in different locations on the sample and to search suitable test spots for the subsequent analysis by the Atomic Force Microscope (AFM). AFM in special modes was employed to measure the maps local mechanical properties (friction, tip adhesion, energy dissipation, etc.).\nOn a selected sample, the cross-sectional structure of the sample was analysed by the Focussed Ion Beam (FIB) and the elemental composition in various thicknesses was documented by the Energy-dispersive X-ray Spectroscopy (EDS).\n Keywords: diamond like carbon layers; Raman spectroscopy; Atomic Force Microscopy; Scanning Electron Microscopy; Focussed Ion Beam; Energy Dispersive Spectroscopy Available at various institutes of the ASCR
Souhrnný report výsledků smluvního výzkumu mezi FZU AV ČR, v.v. i. a HVM Plasma s.r.o. za rok 2016

Několika diagnostickými metodami byly zkoumány vzorky ochranných vrstev na bázi DLC (Diamond-like-Carbon) na různých substrátech (testovací tělíska i reálné součástky). Pomocí Ramanovské spektroskopie ...

Mates, Tomáš; Fejfar, Antonín; Ledinský, Martin; Vetushka, Aliaksi; Pikna, Peter; Bauerová, Pavla
Fyzikální ústav, 2017

Nanopatterning of Silicon Nitride Membranes
Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
2017 - English
Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The principle of silicon nitride membranes preparation is based on the wet anisotropic etching of the bottom side of the silicon wafer with crystallographic orientation (100). While the basic procedure for the preparation of such membranes is well known, the nano patterning of thin membranes presents quite important challenges. This is partially due to the mechanical stress which is typically presented within such membranes. The resolution requirements of the\nmembrane patterning have gradually increased. Advanced lithographic techniques and etching procedures had to be developed. This paper summarizes theoretical aspects, technological issues and achieved results. The application potential of silicon nitride membranes as a base for multifunctional micro system (MMS) is also\ndiscussed. Keywords: e-beam writer; silicon nitride membranes; nano patterning; anisotropic etching Available at various institutes of the ASCR
Nanopatterning of Silicon Nitride Membranes

Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The ...

Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
Ústav přístrojové techniky, 2017

Analytical solution for charged fluid pressure profiles - circulation in combined electromagnetic field
Kovář, J.; Slaný, P.; Stuchlík, Z.; Karas, Vladimír; Trova, A.
2017 - English
We introduce a general transformation leading to an integral form of pressure equations characterizing equilibrium configurations of charged perfect fluid circling in strong gravitational and combined electromagnetic fields. The transformation generalizes our recent analytical treatment applicable to electric or magnetic fields treated separately along with the gravitational one. As an example, we present a particular solution for a fluid circling close to a charged rotating black hole immersed in an asymptotically uniform magnetic field. Keywords: charged perfect fluid; toroidal structures; compact object Fulltext is available at external website.
Analytical solution for charged fluid pressure profiles - circulation in combined electromagnetic field

We introduce a general transformation leading to an integral form of pressure equations characterizing equilibrium configurations of charged perfect fluid circling in strong gravitational and combined ...

Kovář, J.; Slaný, P.; Stuchlík, Z.; Karas, Vladimír; Trova, A.
Astronomický ústav, 2017

Hysteresis behavior of shocks in low angular momentum flows
Suková, Petra
2017 - English
In this work we present the GRMHD 1D simulations of accreting matter with variable angular momentum. We focus on the existence and behaviour of the shock in the flow. We show that the location of the shock front responds to the change of the angular momentum, which also causes the accretion rate onto the black hole to vary on different time scales. We study the possible hysteresis behaviour of the shock\nfront during the time evolution of the flow. We discuss the potential observational effects of this phenomenon. Keywords: black hole; microquasars; accretion flows Fulltext is available at external website.
Hysteresis behavior of shocks in low angular momentum flows

In this work we present the GRMHD 1D simulations of accreting matter with variable angular momentum. We focus on the existence and behaviour of the shock in the flow. We show that the location of the ...

Suková, Petra
Astronomický ústav, 2017

Deformation of thin self-standing mask at inhomogeneous irradiation.
Koláček, Karel; Schmidt, Jiří; Frolov, Oleksandr; Štraus, Jaroslav; Chalupský, Jaromír; Choukourov, A.
2017 - English
Flatness of the mask is one of key features influencing the quality of image. Among factors that can affect mask flatness belongs inhomogeneous illumination. This does not apply to lithography, but to experiments that use only discrete parts of mask e.g. for nanostructuring or other type of material research. It is shown that even single EUV laser shot (laser wavelength ~46.9 nm, pulse duration ~1.5 ns, focused pulse energy ~20 .mu.J, peak fluency 48 J/cm2) not only deforms the mask, but also changes mask-substrate distance. In our case two kinds of grids (one circular with rectangular windows 7.5x7.5 μm and bars 5 micro m (period 12.5x12.5 micro m), other rectangular with rectangular windows 3.2x1.2 μm and bars 0.8 micro m (period 4x2 micro m)) were attached to PMMA substrate and exposed to one or five superimposed focused laser shots. The mask (grid) deformation was inferred from the changes of diffraction pattern engraved into PMMA. Keywords: interaction of XUV radiation with solid surface; nanostructuring; nanopatterning; XUV diffraction Available at various institutes of the ASCR
Deformation of thin self-standing mask at inhomogeneous irradiation.

Flatness of the mask is one of key features influencing the quality of image. Among factors that can affect mask flatness belongs inhomogeneous illumination. This does not apply to lithography, but to ...

Koláček, Karel; Schmidt, Jiří; Frolov, Oleksandr; Štraus, Jaroslav; Chalupský, Jaromír; Choukourov, A.
Ústav fyziky plazmatu, 2017

The role of pre-ionization on EUV capillary laser profile.
Štraus, Jaroslav; Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr
2017 - English
The profile of EUV capillary laser beam was believed to be an annulus and a corresponding theory for its explanation was generally accepted. Nevertheless, our recent detailed observation shows, that the laser profile can be remarkably influenced by the parameters of pre-pulse, serving for working gas pre-ionisation before introduction the main current into the capillary. The examples of possible profile shapes and corresponding parameters are presented. Keywords: Pre-pulse; capillary XUV laser beam profile Available at various institutes of the ASCR
The role of pre-ionization on EUV capillary laser profile.

The profile of EUV capillary laser beam was believed to be an annulus and a corresponding theory for its explanation was generally accepted. Nevertheless, our recent detailed observation shows, that ...

Štraus, Jaroslav; Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr
Ústav fyziky plazmatu, 2017

Flow Dynamics in the Vicinity of Tandem Buildings
Gnatowska, R.; Kellnerová, Radka; Uruba, Václav
2017 - English
The flow-field in the vicinity of tandem building model in a wind tunnel will be subjected to analysis of dynamics. The model is 3D consisting of the two blocks of different sizes arranged in a streamwise direction. Experiments were performed using time-resolved PIV technique in several measuring planes to capture both spatial and dynamical features. Keywords: PIV experiment; tandem building arrangement; wind tunnel Available at various institutes of the ASCR
Flow Dynamics in the Vicinity of Tandem Buildings

The flow-field in the vicinity of tandem building model in a wind tunnel will be subjected to analysis of dynamics. The model is 3D consisting of the two blocks of different sizes arranged in a ...

Gnatowska, R.; Kellnerová, Radka; Uruba, Václav
Ústav termomechaniky, 2017

31st Symposium on anemometry: proceedings
Chára, Zdeněk; Klaboch, L.
2017 - Czech
Sborník z konference 31st symposium o anemometrii. Konference byla zaměřena na experimentální techniky používané v mechanice tekutin.\n Proceedings of 31st Symposium on Anemometry. The conference was oriented on the experimental techniques applied in fluid mechanics. Keywords: anemometry; conference; proceedings Available at various institutes of the ASCR
31st Symposium on anemometry: proceedings

Sborník z konference 31st symposium o anemometrii. Konference byla zaměřena na experimentální techniky používané v mechanice tekutin.\n...

Chára, Zdeněk; Klaboch, L.
Ústav pro hydrodynamiku, 2017

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