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Drobní savci v potravě sovy pálené ve východním Středomoří.
Šindelář, Jiří ; Horáček, Ivan (vedoucí práce) ; Anděra, Miloš (oponent)
Obsáhlý materiál kosterních pozůstatků savců z potravy sovy pálené v oblasti východního Středomoří byl zpracován a různými technikami chorologické a morfometrické analýzy zhodnocen. Ve vlastním souboru, obsahujícím doklady nejméně 8400 jedinců, je zastoupeno celkem 45 druhů hmyzožravců, hlodavců a netopýrů, kteří reprezentují podstatnou část fauny regionu. Podrobně byla zhodnocena chorologická skladba tafocenos a meziregionální rozdíly, projevující se především odlišnostmi v zastoupení satelitních a akcesorických elementů. Vysoce průkazné je ochuzení tafocenos izolovaných ostrovů (Kypr, Karpathos, zčásti Kréta), kde chybí křečkovití, hrabošovití, C. leucodon aj. a v dominanční struktuře se zásadním dílem uplatňuje krysa Rattus rattus, představující zde invazní druh, výrazně úspěšnější než v členitých kontinentálních kontextech. Druhová diverzita zkoumaných tafocenos je pozitivně korelována s geografickou šířkou (tafocenosy severnějších regionů jsou výrazně bohatší) a negativně s ostrovním efektem a stupněm aridizace. Morfometrická analýza tří nejhojnějších druhů rejskovitých ukázala z hlediska zkoumaného regionu výrazně homogenní distribuci metrických charakteristik jednotlivých druhů, v lokálním měřítku se však tato homogenita u některých druhů ztrácí. U C. leucodon je patrný aspekt klinální...
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HYDROGENATION PROPERTIES OF BALL-MILLED Mg-Ti-C-Zr COMPOSITE
Král, Lubomír ; Čermák, Jiří ; Roupcová, Pavla
The hydrogen storage properties of ball-milled Mg-Ti-Zr-C composite (1.8 wt.% Ti, 1.9 wt.% Zr and 0.2 wt.% C) were investigated. It has been previously shown, that the addition of Ti, Zr and C improved its storage properties. This beneficial effect of additives upon hydrogen storage properties can be explained by catalysis by the particles rich in Ti or Zr located on the surface of Mg grains. They provide effective pathways for the hydrogen diffusion into the MgH2. The morphological and microstructural characteristics were investigated by scanning electron microscopy and by X-ray diffraction. The hydrogen sorption was measured by Sieverts method using Setaram PCT-Pro device. In this paper, sorption behaviour of the composite after ball-milling and after aging on the air was compared. The ball-milled composite adsorbed 3.5 wt.% H2 within 10 min at 623 K. However, hydrogen storage capacity of the composite aged on the air for 7 months remarkably decreased: The aged composite adsorbed within 10 min only 2 wt.% H2 at 623 K and the sorption capacity decreased from 4.7 wt.% H2 to 2.1 wt.% H2.
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STRAIN ENGINEERING OF THE ELECTRONIC STRUCTURE OF 2D MATERIALS
del Corro, Elena ; Peňa-Alvarez, M. ; Morales-García, A. ; Bouša, Milan ; Řáhová, Jaroslava ; Kavan, Ladislav ; Kalbáč, Martin ; Frank, Otakar
The research on graphene has attracted much attention since its first successful preparation in 2004. It possesses many unique properties, such as an extreme stiffness and strength, high electron mobility, ballistic transport even at room temperature, superior thermal conductivity and many others. The affection for graphene was followed swiftly by a keen interest in other two dimensional materials like transition metal dichalcogenides. As has been predicted and in part proven experimentally, the electronic properties of these materials can be modified by various means. The most common ones include covalent or non-covalent chemistry, electrochemical, gate or atomic doping, or quantum confinement. None of these methods has proven universal enough in terms of the devices' characteristics or scalability. However, another approach is known mechanical strain/stress, but experiments in that direction are scarce, in spite of their high promises.\nThe primary challenge consists in the understanding of the mechanical properties of 2D materials and in the ability to quantify the lattice deformation. Several techniques can be then used to apply strain to the specimens and thus to induce changes in their electronic structure. We will review their basic concepts and some of the examples so far documented experimentally and/or theoretically.
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HYDROGEN ABSORPTION IN A-Co30Fe55B15
Čermák, Jiří ; Král, Lubomír ; Roupcová, Pavla
Hydrogen solved in amorphous alloys (AAs) influences their magnetic characteristics. AAs are also perspective\nas additives that can improve hydrogen storage kinetic in certain types of ball-milled hydrogen storage\nmaterials (HSMs). Therefore, knowledge of hydrogen solubility and hydrogen sorption kinetics in AAs are of a\ngreat importance for aimed design both AAs with optimal magnetic parameters and HSMs with desired sorption\ncharacteristics. In the present paper, amorphous alloy Co30Fe55B15 (an example of the type a-TM1xTM2y Bz ;\nTM - transition metal) was investigated. Hydrogen concentration c H was measured by Sieverts method in\ntemperature interval from T = 150 °C to T = 350 °C under hydrogen pressure p up to 6 MPa. It was found that\nc H was an increasing function of p and its maximum value was typically 0.5 wt.% H2 at 350 °C and 6 MPa.\nHowever, when the alloy was preliminary hydrogen charged (PHC), the pressure dependence of total c Htot in\nthe first absorption cycle(s) is non-monotonous in dependence on PHC conditions. For the sake of comparison,\nthe same absorption characteristics were measured also in Mg2Ni intermetallic that is a common constituent\nin Mg-based HSMs. Comparing Co30Fe55B15 and Mg2Ni, it was concluded that Co30Fe55B15 shows lower\nhydrogen solubility, but much better absorption kinetics.
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Deposition of Titania from Solution by Hybrid Water-Stabilized Plasma Torch
Mušálek, Radek ; Medřický, Jan ; Tesař, Tomáš ; Kotlan, Jiří ; Lukáč, František
Thermal spraying with liquid feedstock presents a novel route for deposition of functional coatings. In this study, possibility of preparation of titania coatings from solution by hybrid water stabilized plasma torch is presented. Coatings were prepared from solution of titanium isopropoxide Ti[OCH(CH3)2]4 in anhydrous ethanol. Fragmentation of feedstock stream in the plasma jet was monitored by shadowgraphy. Deposition was carried out on steel samples mounted to the cooled rotating carousel. Cross-sectional images from SEM microscope showed successful formation of the deposit with dual morphology consisting of fine feather-like features combined with bigger droplets. X-ray diffraction revealed formation of nanometric rutile crystallites.
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Black Chromia Coatings on Metal Tubes for the Solar Collectors
Brožek, V. ; Mastný, L. ; Novák, M. ; Vilémová, Monika ; Kubatík, Tomáš František
This paper describes the results of the first phase of the study preparation, structure and properties of coatings modification of black chromium oxide on copper, aluminium, iron and zirconium tubes for solar collectors. The coatings are prepared by plasma spraying of liquid chromate method which is known as liquid precursor plasma spraying. Coatings have the function of an energy trap for thermal radiation wavelengths of 1 μm – 3 μm i.e. in the IR region. At the same time, the coating increases the corrosion resistance of metal substrates. The nanometric structure and thickness of the coating depend of the feeding distance and the concentration of chromate precursors. For the deposition of nanometric splats of melt chromiumIII oxide, a new type of feeder that injects precursors into the water stabilized thermal plasma produced by the WSP® generator has been\ndeveloped.\n
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Miřenka Čechová
Janečková, Kateřina ; PETIŠKOVÁ, Ladislava (vedoucí práce) ; SOPROVÁ, Jana (oponent)
Monografická práce se zaměřuje na tvorbu Miřenky Čechové, jedné z předních
osobností našeho současného jevištního umění. Přibližuje její osobnost a
umělecký vývoj od studia tanečního umění k mimickému a fyzickému divadlu.
Představuje její přínos pro současné české fyzické divadlo a odkazuje na její
zahraniční úspěchy. Všímá si její úlohy jako spoluzakladatelky souborů
Theatro Pantomissimo a Spitfire Company. Mapuje tvorbu těchto souborů a
odkrývá pracovní i pedagogické postupy při přípravě autorských představení.
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