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The Influence of Nanoparticles on The Properties of Hard Polyurethane Foams
Eliáš, Filip ; Kotlík, Josef (referee) ; Petrůj, Jaroslav (advisor)
The theoretical part of the thesis focuses on general principles of polyurethane chemistry. Nanotechnologies are also discussed, in particular using nanoparticles in the production of polyurethane foams. There are also mentioned selected preparation methods of silver and titanium dioxide nanoparticles. The experimental part describes mainly a novel method for synthesis of the concentrated solution of titanium dioxide nanoparticles in glycerol and their analysis by using confocal microscopy, scanning electron microscopy, dynamic light scattering and UV-VIS spectroscopy. Finally, there are suggested particular steps for further investigation of prepared nanoparticles for the production of rigid polyurethane foams, and also for other applications.
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Analysis and modification of thin layers using ion beams
Jonner, Jakub ; Lörinčík, Jan (referee) ; Bábor, Petr (advisor)
This diploma thesis deals with analysis and modification of thin layers using ion beams. The first part of this diploma thesis deals with phenomena accompanying ion beam bombardment of solid matter. The second part of this diploma thesis is concerned with Secondary Ion Mass Spectroscopy (SIMS) and Low Energy Ion Scattering (LAIS). This work convey some basic information about these two techniques and it also deals with some benefits result in their connection into parallel depth profiling mode (such as better depth resolution of the LEIS profile, quantification of the SIMS). These benefits are demonstrated on MoSi film measurement. Within the framework of this thesis a new UHV manipulator was designed. This new UHV manipulator is equipped with precise stepper UHV motor and since the proportions are smaller, the manipulation with a sample in a space limited UHV chamber is much more comfortable and more precise. The third part of this diploma thesis deals with ion-beam induced transformation of epitaxially grown Fe films with thickness of 22 monolayer (ML) and 44 ML on Cu(100) single crystal at room temperature. Metastable Fe films of 22 ML thickness were prepared in CO pressure and 44 ML Fe films were prepared by co-evaporation of Fe with Fe64Ni36 (invar). Structural changes are analyzed by scanning tunneling microscopy and low-energy electron diffraction. The aim of this thesis is to discuss the influence of the sputtering parameters such as ion dose and ion energy on the nucleation of bcc nanocrystals, their growth, final shape and size. The influence of different Ni concentration on stability of 44 ML thick Fe films is also discussed.
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The synthesis and development of new catalyst with the bipyridine scaffold.
Kadlčíková, Aneta ; Kotora, Martin (advisor) ; Starý, Ivo (referee) ; Veselý, Jan (referee)
1 Abstract Chiral N,N'-dioxides serve as very useful catalysts in various enantioselective reactions. I developed a simple and efficient method for preparation of new unsymmetrically substituted axially chiral bis(tetrahydroisoquinolines)-N,N'-dioxides, based on "one-pot" [2+2+2]-cyclotrimerization of a tetrayne with benzonitrile and (R)-tetrahydrofurancarbonitrile catalyzed by CpCo(CO)2 under microwave irradiation (scheme 1)1,2 . First, the prepared chiral N,N'-dioxides were used as catalysts in highly enantioselective allylations of variously substituted aromatic, aliphatic and α,β-unsaturated aldehydes. The corresponding homoallylalcohols were obtained with ee up to 99%. Two obtained chiral homoallylalcohols prepared by allylation were used as a building-blocks for synthesis of some natural products such as (S)-(-)-Goniothalamin (scheme 2)3 . Second, the chiral N,N'-dioxides were also used for the epoxide ring opening of various meso-epoxides with tetrachlorosilane giving rise to chlorohydrines in moderate enantioselectivities (up to 64% ee) (scheme 3)4 . N N OScheme 1 + N N O O O CpCo(CO)2 MCPBA O NC NC SiCl3 Cat. (1-5mol%) O O (S)-(-)-Goniothalamin, 97% ee Ph R OH up to 99% ee Scheme 2 R R R = phenyl, alkyl O OHClSiCl4 up to 64% ee R H O R= Ar, alkyl, ArCH=CH, alkyl-CH=CH Ph H Scheme 3 Cat. O Cat....
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Fotogenerace nosičů náboje v polymerních nanokompozitech
Pfleger, Jiří ; Pavlík, Martin ; Vohlídal, J.
Polymer nanocomposites seem to be promising systems for solar cell application with polythiophene acting as photosensitizer and charge transport medium. The electrophoretic deposition proved to be suitable method for preparation nanostructured core/shell functional layers. The simplicity, fast operation rate and the possibility of covering surfaces of irregular shape, as well as a good quality of prepared films are the major advantages of the method.
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Optimal fibre cross section shape for cladding-pumped fibre lasers and amplifiers
Peterka, Pavel ; Kašík, Ivan ; Matějec, Vlastimil
The efficiency of the cladding-pumped fibre amplifier critically depends on the coupling of the pump radiation from the inner cladding to the single mode signal core, doped with rare earth ions /Er, Yb, .../. This coupling depends on the cross sectional shape of the inner cladding. In the paper, the conditions of the optimal shape are defined. Verification of these conditions in case of several specific examples, including experimental fibre prepared in the author's laboratory, is shown.
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Tuned semiconductor laser for the diagnostic of the channel waveguides
Ondráček, František ; Skalský, Miroslav ; Čtyroký, Jiří
In contribution is described new measuring set up with tuned semiconductor laser and there are given first results of spectral losses and group refractive index in various channel waveguides by using a resonator method. The waveguides were prepared in special glasses by ion exchanges method and in LiNbO.sub.3./sub. crystal by proton exchange and also by titan difusion. Experimental results have demonstrated accuracy and rate of this arangement. In conclusion we have shown the possibility of the next research.
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