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Characterization of Ta-B-C nanostructured hard coatings
Buršík, Jiří ; Buršíková, V. ; Souček, P. ; Zábranský, L. ; Vašina, P.
Microstructure and mechanical properties of Ta-B-C nanocrystalline layers prepared by magnetron sputtering were studied. DC magnetron sputtering was used to prepare thin layers on rotated substrates. Various deposition parameters were tested. Microstructure of layers was studied by means of scanning and transmission electron microscopy on thin lamellar cross sections prepared using a focussed ion beam. Both undisturbed layers and the volume under relatively large indentation prints (load of 1 N) were observed. The microstructure observations were correlated with mechanical properties characterized by means of nanoindentation experiments in both the static and the dynamic loading regime. Elastic modulus, indentation hardness and fracture resistance of prepared nanostructured coatings were evaluated and discussed.
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Iron Functionalized Nanoparticles of Titanium Dioxide
Volfová, Lenka ; Nižňanský, Daniel (advisor) ; Tabor, Edyta (referee)
Diploma thesis Iron Functionalized Nanoparticles of Titanium Dioxide Lenka Volfová 2017, ABSTRACT Iron-functionalized TiO2 were obtained by hydrolysis of aqueous solutions of titanyl sulfate with addition of ferric nitrate with ammonium hydroxide and the reaction filtered and washed with hydrogen peroxide. The colloid solutions thus prepared were lyophilized and the products were subsequently annealed at three different temperatures of 650 řC, 800 řC and 950 řC. The prepared doped materials were characterized by powder X-ray diffractometry, electron microscopy, infrared spectroscopy, Mössbauer spectroscopy, UV/VIS spectroscopy, thermogravimetric analysis and differential thermal analysis, and measurement of the specific surface area. Photocatalytic activity was determined by measuring of the decomposition of kinetics of 4-chlorophenol in an aqueous solution in the ultraviolet and visible area. For comparison of activity in the UV area and in the visible area were used a previously prepared highly photoactive specimen and standard TiO2 from Kronos, respectively. Keywords: Doped titanium dioxide, nanostructure, X-ray diffraction, electron microscopy, Mössbauer spectroscopy, suppression of photoactivity
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Nanoscale phases on surface Fe-6Si magnetic sheets
Švábenská, Eva ; Roupcová, Pavla ; Král, Lubomír ; Bulín, Tomáš ; Vondráček, Martin ; Foldyna, Josef ; Čechal, J. ; Schneeweiss, Oldřich
Analysis of the nanoscale phases which appear on the surface Fe-6Si samples were carried out after the various treatments – grinding and etching, annealing, and water jet abrasion. The basic information on structure, chemical and phase composition was obtained by X-Ray Powder Diffraction (XRD), Scanning Electron Microscopy with EDX, Glow Discharge Optical Emission Spectrometry (GDOES), Mössbauer Spectroscopy and X-ray Photoelectron Spectrometry (XPS). The results show high stability of the surface phase composition after the mechanical and heat treatments. Results obtained from the surface analysis in micrometer depth (XRD, EDX, GDOES) do not show any changes after the different treatments. Iron oxides were detected in XPS and conversion electron Mössbauer spectra (CEMS) which analyze the surface composition in a nanometer scale. In addition to, fine changes in atomic ordering on the surface can be observed after mechanical and heat treatments in the CEMS spectra.
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Preparation of nanostructures using nanoporous template
Dzuro, Matej ; Hrdý, Radim (referee) ; Drbohlavová, Jana (advisor)
The aim of the work described in this paper is to prepare electrochemically an optical sensor consisting of TiO2 quantum dots (QDs) using nanoporous Al2O3 template in the first step and to modify the surface of QDs with gold layer by evaporation process, again using nanoporous template, in the second step. This easy, cheap and rapid approach provides homogenous and highly ordered distribution of both nanostructures on substrate. The final objective is to characterize the physical parameters and fluorescent properties of TiO2/Au sensor designed for optical detection of biomolecules such as DNA and proteins.
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Strukturní studie tenkých titaničitých vrstev
Šolcová, Olga ; Matějová, Lenka ; Krejčíková, Simona ; Matěj, Z. ; Kužel, R. ; Strýhal, Z.
Our study is focused on the relationship between the number of oxyethylene units in nonionic surfactants used for preparation of a set of various titania layers by dip-coating via the sol-gel method and morphology, roughness, type of titania phase and textural properties of the prepared titania layers. Additionally, the contact angle determination as a rapid and easy method suitable for evaluation of the surface quality of the prepared titania layer has been tested, too.
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Distribuce porů z permporometrických měření
Šolcová, Olga ; Schneider, Petr
Two measurement modes for obtaining wet-curves were suggested and verified. In the figure the obtained wet and dry curves for two catalysts are shown. It was verified that LEPP gives consistent pore size distribution of flow-through pores and, thus, should be tried as the standard texture characteristic suitable for prediction and/or simulation of gas flow in porous media
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