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Ab initio calculation of doping in Ni2MnGa alloy
Janovec, Jozef ; Černý, Miroslav (referee) ; Zelený, Martin (advisor)
Cieľom tejto práce je teoretické štúdium systému Ni-Mn-Ga, vykazujúceho efekt magnetickej tvarovej pamäti. Pri výpočtoch bola použitá metóda Exaktných Mufiin-Tin Orbitálov v kombinácii s aproximáciou koherentného potenciálu vrámci Korringa-Kohn-Rostoker formalizmu. Totálna energia bola spočítaná pomocou metódy úplnej nábojovej hustoty. Skúmaný bol vplyv dopovania zinkom alebo kadmiom na totálne energie pozdĺž tetragonálnej deformačnej dráhy a následne na teplotu martenzitickej premeny TM a Curieho teplotu TC. Taktiež boli skúmané nestechiometrické zliatiny prebytkom Mn na úkor Ga. Výsledky predikujú nárast TM po všetkých pozorovaných substitúciách v podmriežke Ga a pokles TM po substitúciách v podmriežke Mn. Curieho teplotu znižujú všetky študované substitúcie s výnimkou zmeny magnetického usporiadania v martensite nestechiometrickej zliatiny.
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Electronic structure and mechanical properties of interfaces in solids
Češka, Jakub ; Šesták, Petr (referee) ; Černý, Miroslav (advisor)
In this work I focus on a theoretical study of the properties of transition metal nitrides (TiN, AlN and VN in the rock-salt structure). In addition to the nitrides themselves, I focus on the interface in systems of multilayers consisting of pairs of these nitrides. For nitrides, I predict the lattice parameter and cleavage energy using ab initio calculations. For the interface, the main goal is to predict the cleavage energy of the interface and to predict the influence that an atom substituted in one of layers on the interface has on the value of cleavage energy. According to the calculations performed, an oxygen atom substituted in the interface has a significant influence on the value of cleavage energy. The value of cleavage energy for the interface with an oxygen atom differs significantly from that for the pure interface. Whether there was a decrease or an increase depended on which of the layers at the interface the oxygen atom was substituted in.
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Lexical Obsolescence and Loss: The Case of Early Modern English (1500-1700)
Volná, Veronika ; Tichý, Ondřej (advisor) ; Fernandez Alcaina, Cristina (referee) ; Černý, Miroslav (referee)
Literature dealing with the development of the English lexicon has been concerned primarily with new additions to the language's vocabulary, such as borrowings, coinages and word formation patterns, while the topic of lexical obsolescence and loss remains under-researched. In the Early Modern period, the rate at which new lexical items appeared in the English language was unprecedented, especially in the years 1590-1620, as documented in the Oxford English Dictionary's online Timelines feature. In tandem with the rapid expanding lexicon, there was a portion of the vocabulary that was undergoing obsolescence or complete disappearance. Over the course of the Early Modern period, English lost a significant portion of its word- stock, including those short-lived coinages or borrowings which had entered the language only several decades or centuries earlier. Using authentic examples from the EEBO (Early English Books Online) corpus, this dissertation provides an insight into the role of lexical obsolescence and loss in the development of Early Modern English. Based on frequency data, a list of candidates for obsolescence has been generated featuring words such as sacerdote (lat.), travalier (fr.), and breastlap (en.), all of which were common at the onset of the Early Modern period but had disappeared...
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Ab initio study of electronic structure of 2D materials
Pekár, Zdenko ; Nezval, David (referee) ; Černý, Miroslav (advisor)
This bachelor’s thesis begins with an overview of basic terminology and principles regarding transition metal dichalcogenides and density functional theory. The theoretical part then brings several examples of atomic configuration of such materials and aproximations for the exchange-correlation functional. The practical part focuses on computational simulation and optimization of cells for various phases of transition metal dichalcogenides and their combinations, and compares their properties to those found in scientific literature and also gathers new, so far untested information about these materials.
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The effect of impurities on the interface cohesion in multilayers in transition metal nitrides
Češka, Jakub ; Zelený, Martin (referee) ; Černý, Miroslav (advisor)
This work deals with the study of transtition metal nitride multilayers using first-principles calculations. Objects of this study are three particular systems AlN / TiN, AlN / VN and TiN / VN. Studied systems are in the B1 structure with an interface along the (001) plane. The main goal is to unravel the effect of impurity on cohesion in these multilayers. The impurity in question is a substitutional O atom replacing N in the lattice. Preferred positions of these substitutions are predicted for three different concentrations of substitution impurity. These predictions are based on the energy balance of substitutions in different positions. Resulting preferred positions within the multilayer may differ depending on the oxygen concentration. In most cases, the preferred position is at the interface between the two nitrides. For such systems with oxygen impurity in the preferred position a cleavage energy along several (001) planes is calculated. The effect of the impurity on the value of cleavage energy depends on its concentration. In the case of AlN / TiN multilayer, a suitable concentration of the impurity may increase the cleavage energy of the weakest link in multilayer compared to clean multilayer. In other cases the presence of impurity either causes a decrease in the cleavage energy or does not significantly affect its value.
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Attitudes of football fans in lower league
Černý, Miroslav ; Janák, Vladimír (advisor) ; Šíma, Jan (referee)
Attitudes of football fans in lower league Objectives: The aim of the work is to find out the attitudes and motives of people to active visitation of football matches in lower league. Then I would like to introdukce a gained knowledges to the head of the clubs in order to reach a higher level of satisfaction of fans. Methods: Questionnaire, interview Results: It will find out the attitudes of fans in lower leagues thanks to mentioned methods of research. The work will present the view of individual behaviour and Leeds of fans in lower league. Keywords: Lower league, football, attitudes, spectators
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Analysis of wave-particle interactions in space plasmas
Černý, Miroslav ; Santolík, Ondřej (advisor) ; Souček, Jan (referee)
This work deals with the linear analysis of plasma waves, especially with the methods of solution of a hot plasma dispersion relation. There are cited some results achieved in the space plasma research and mapped current numerical methods of their analysis. Besides, this work introduces a new numeric procedure, computer code PDRS (Plasma Dispersion Relation Solver), which allows finding solution of a dispersion function of a cold or hot plasma with general distribution function. It also demonstrates the usage of the PDRS methods on real examples of waves in space plasma based on the spacecraft Cluster measurement.
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Electronic structure and mechanical properties of interfaces in solids
Češka, Jakub ; Šesták, Petr (referee) ; Černý, Miroslav (advisor)
In this work I focus on a theoretical study of the properties of transition metal nitrides (TiN, AlN and VN in the rock-salt structure). In addition to the nitrides themselves, I focus on the interface in systems of multilayers consisting of pairs of these nitrides. For nitrides, I predict the lattice parameter and cleavage energy using ab initio calculations. For the interface, the main goal is to predict the cleavage energy of the interface and to predict the influence that an atom substituted in one of layers on the interface has on the value of cleavage energy. According to the calculations performed, an oxygen atom substituted in the interface has a significant influence on the value of cleavage energy. The value of cleavage energy for the interface with an oxygen atom differs significantly from that for the pure interface. Whether there was a decrease or an increase depended on which of the layers at the interface the oxygen atom was substituted in.
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Ab initio calculation of doping in Ni2MnGa alloy
Janovec, Jozef ; Černý, Miroslav (referee) ; Zelený, Martin (advisor)
Cieľom tejto práce je teoretické štúdium systému Ni-Mn-Ga, vykazujúceho efekt magnetickej tvarovej pamäti. Pri výpočtoch bola použitá metóda Exaktných Mufiin-Tin Orbitálov v kombinácii s aproximáciou koherentného potenciálu vrámci Korringa-Kohn-Rostoker formalizmu. Totálna energia bola spočítaná pomocou metódy úplnej nábojovej hustoty. Skúmaný bol vplyv dopovania zinkom alebo kadmiom na totálne energie pozdĺž tetragonálnej deformačnej dráhy a následne na teplotu martenzitickej premeny TM a Curieho teplotu TC. Taktiež boli skúmané nestechiometrické zliatiny prebytkom Mn na úkor Ga. Výsledky predikujú nárast TM po všetkých pozorovaných substitúciách v podmriežke Ga a pokles TM po substitúciách v podmriežke Mn. Curieho teplotu znižujú všetky študované substitúcie s výnimkou zmeny magnetického usporiadania v martensite nestechiometrickej zliatiny.
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