National Repository of Grey Literature 33 records found  beginprevious20 - 29next  jump to record: Search took 0.01 seconds. 
Institute of Scientific Instruments: An Overview Presenatation
Kolařík, Vladimír ; Zobač, Martin ; Fořt, Tomáš ; Vlček, Ivan ; Dupák, Libor ; Mikmeková, Šárka ; Mikmeková, Eliška ; Mrňa, Libor ; Horáček, Miroslav ; Sobota, Jaroslav
The aim of this contribution is to present the Institute of Scientific Instrument of the Academy of Sciences of the Czech Republic, mainly from the potential of applied research viewpoint. It covers mainly the six application fields including material study of metals and alloys, nano layer residual stress observation methods, 2 kW fibre laser, impact testing of hard coatings, e-beam welding, machining and engraving, and finally e-beam lithography. Recently achieved results as well as the new application potential are presented. Furthermore, each topic is assumed to have a separate presentation prepared in more details within this event. A brief overview follows. Scanning low energy electron microscopy (SLEEM) is increasingly becoming recognized as a valuable analytical tool in the field of materials science. The SLEEM is also used for observation of compressive stress in nano layers that leads to wrinkling and film delamination. Using the fibre laser, we can offer 3D laser welding and cutting of various type of materials and laser surface hardening too. For the hard coatings testing and evaluation of their impact resistance a new method was suggested (Dynamic Impact Wear Test). During testing the specimen is cyclically loaded by tungsten carbide ball that impacts of the coating/substrate surface. In house e-beam welding machine allows for welding, machining, engraving and other utilizations of intense electron beam. The group of micro lithography is able to prepare micro and nano structures in thin layers of metals and other materials; including the characterization of the realized structures
Comparison of techniques for diffraction grating topography analysis
Matějka, Milan ; Rek, Antonín ; Mika, Filip ; Fořt, Tomáš ; Matějková, Jiřina
There are a wide range of analytical techniques which may be used for surface structure characterization. For high resolution surface investigations, two commonly used techniques are Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Both techniques are capable resolve surface structure down to the nanometer in scale. However the mechanism of topography imaging and type of information acquired is different.
Optical and scanning electron microscopies in examination of ultrathin foils
Konvalina, Ivo ; Hovorka, Miloš ; Fořt, Tomáš ; Müllerová, Ilona
Very low energy scanning transmission electron microscopy is emerging as a novel tool for examination of ultrathin foils to learn more about the electron structure of solids. The electron micrographs provide image contrasts governed by the effective thickness of the sample proportional to the inner potential and at lowest energies the local density of electron states in the direction of impact of the electron wave starts to dominate. The optical methods are used during the sample preparation. The laser confocal microscope Olympus Lext OLS 3100 was used for preliminary observations of the 3 nm C foil prepared by magnetron sputtering in nitrogen atmosphere on a flat glass covered by a disaccharide layer.
Transmission of Electrons through Thin Films by Scanning Low Energy Electron Microscopy
Müllerová, Ilona ; Hovorka, Miloš ; Fořt, Tomáš ; Frank, Luděk
For examination of thin films by transmitted electrons (TE) the Transmission Electron Microscope is used at primary beam energies in hundreds of keV. The Scanning Electron Microscopes (SEM) utilize reflected electrons in order to image surfaces but recently the TE mode has been introduced into SEM at much lower electron energies.
Sputtered coatings of SiNx:H on H2 plasma etched mono-Si substrate
Hégr, O. ; Boušek, J. ; Fořt, Tomáš ; Sobota, Jaroslav ; Vavruňková, V. ; Bařinka, R. ; Poruba, A.
The paper deals with cleaning, activation and ability of hydrogenation of monocrystalline silicon surface with the help of plasma etching in H2. Using the input gases Ar/H2 it is possible to initiate silicon surface chemical reactions acting similar to a standard chemical etching. The process is combined with deposition of SiNx:H layers on plasma etched substrate.
Characterization of multicrystalline solar cells with LBIC method in different wavelength
Fořt, Tomáš ; Jandová, K. ; Vaněk, J. ; Boušek, J.
For the determination of defects in the solar cells was used a method LBIC (Light Beam Induced Current). We use LED light source with various wavelengths to reveal the different types of defects. Using multiple wavelengths enables detecting defects in different depths. Surface defects can be observed in shorter wavelengths (400nm and 470nm). The junction region is well observed at wavelengths close to 525nm. Defects in the base material are visible using the light at a wavelength of 630nm or 890nm.
Studium mechanických vlastností DLC tenkých vrstev deponovaných v jedno a dvoufrekvenčním kapacitním výboji
Buršíková, V. ; Stoica, A. ; Sobota, Jaroslav ; Grossman, Jan ; Fořt, Tomáš ; Klapetek, P. ; Buršík, Jiří ; Bláhová, O.
Nanostructured diamond-like carbon coatings were deposited on several different substrate materials (silicon, glass, polycarbonate and steel) in single (13.56 MHz) and dual capacitive r.f. discharges (LF=100-300kHz, HF =13.56 MHz). The objective of our study was to find the optimum combination of the high and low frequency (continuous or pulsed) excitation enabling to cover uneven substrate surfaces and significant lowering of the internal stress in films.
Studium mechanických vlastností gradovaných amorfních DLC povlaků deponovaných PECVD
Buršíková, V. ; Stoica, A. ; Sobota, Jaroslav ; Grossman, Jan ; Fořt, Tomáš ; Klapetek, P. ; Buršík, Jiří ; Peřina, Vratislav ; Bláhová, O.
For optimisation of performance of the coating there is necessary to optimise the following materials parameters: the elastic modulus, hardness, surface strength, film fracture toughness and film-substrate adhesion. We proposed to protect the substrate surface with graded coating, which has monotonically graded elastic modulus and Poisson's ratio.
Tribologické chovaní tvrdých uhlíkových kompozitních vrstev
Fořt, Tomáš ; Grossman, Jan ; Sobota, Jaroslav ; Vítů, T. ; Novák, R.
Carbon hard composite coatings were exposed to dynamical load and high temperature pin-on-disc CSM Tribometer. To evaluate the impact resistance of thin hard composite coating in dynamic loading wear applications an impact test was used. The sliding tests in air were carried out in the range from room temperature to 500 °C with controlled relative humidity. Hardness, elastic modulus and fracture toughness of deposited coatings were studied by indentation technique using Fisherscope H100 tester.
Mechanical Properties of TiCN Layers
Bláhová, O. ; Prušáková, L. ; Sobota, Jaroslav ; Fořt, Tomáš ; Grossman, Jan ; Fajkus, M.
The work deals with problems of evaluation mechanical properties of thin wear resistance layers deposited by PACVD method. Nanoindenter XP carried out the nanoindentation measurements with continuous stiffness measurement. The tribological properties were carrying out by high temperature pin-on-disk tribometer and by impact tester.

National Repository of Grey Literature : 33 records found   beginprevious20 - 29next  jump to record:
See also: similar author names
2 Fořt, Tadeáš
Interested in being notified about new results for this query?
Subscribe to the RSS feed.