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Study of optical properties of perovskites and their precursors thin films
Blahut, Jan ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
The thesis is focused on the study of the optical properties of thin films of perovskites and their precursors. The first two chapters of the theoretical part are theoretical introduction to the studied problems, they discuss the basics of electromagnetic radiation and its interaction with matter and basic informations about perovskite materials, especially their semiconductor structure. The remaining two chapters deal with specific principles and practical uses of methods and procedures for the preparation of thin films, as well as the instrumentál characteristics of thin films in terms of their optical properties. The experimental part is focused on the preparation of solutions of perovskites and their precursors, where the replication and optimization of published procedures took place, the preparation of thin layers of these solutions by the spin coating method and their ellipsometric characterization using the Tauc plot method, modeling and fitting of the experimentally determined data, which led to the determination of the index refraction, absorption coefficient and band gap width of individual materials.
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Koncepce pohonů osobních automobilů
Pospíšil, Jan
This work is focused on the conception of the drives cars. You will become acquainted with the various concepts pioneered in the field of passenger cars, with the advantages and disadvantages of each approach and the current situation. Further mention of the development of concepts for passenger cars and where it will go in the future. In addition, there will be described and technical solutions specific vehicle. First of all, familiarize yourself with the concepts that are 4, but each is unique. In the historical part I will focus on the pioneers and interestingly designed cars. Development of the concept of drives already a few years point to the use of alternative fuels and hybrid technology.
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Computer-Controlled Planting
Pospíšil, Jan ; Šimek, Václav (referee) ; Růžička, Richard (advisor)
This work is focused on the issue of plant cultivation in domestic conditions. We focused on the automation of the growbox using the Wemos D1 R32 ESP32 board, which then consists of the design and implementation of three parts of the solution, i.e. the growbox itself, including the sensors needed to maintain ideal conditions for the plant being grown, the user applications, for interpreting the values and the configuration of the growbox. Application to collect data from growbox, for later analysis. The solution includes the creation of a demonstration growbox, software for all parts and comparison with available home growing systems.
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On Market Efficiency, Optimal Distributional Trading Gain, and Utility Maximization
Navrátil, Robert ; Večeř, Jan (advisor) ; Witzany, Jiří (referee) ; Pospíšil, Jan (referee)
On Market Efficiency, Optimal Distributional Trading Gain, and Utility Maximization Robert Navr'atil The aim of this thesis is multifold. First, using results from the optimal distributional trading gain problem, we determine a utility-maximizing portfolio that optimizes the benefit an agent may receive by trading the difference between his perceived future distribution of a security price and the risk-neutral density provided by the corresponding option market. Moreover, we show how one can fit the risk-neutral density directly from option market data using the SVI parameterization. We use integer programming with kernel search heuristics to statically replicate the optimal payoff. Second, we show that the United States equity market was inefficient during the weeks following the initiation of the COVID-19 pandemic. This is demonstrated by showing that utility-maximizing agents over the period ranging from mid-February to late March 2020 could generate statistically significant profits by utilizing historical price and virus- related data to forecast future equity ETF returns. Finally, we focus on the passport option. We present a version of insurance of a traded account that symmetrically treats both of its underlying assets. In our approach, we impose a natural symmetric limit in which the agent can...
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Study of electric properties of thin films of perovskite precursors
Harna, Václav ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
High efficiency perovskite solar cells may be the solution to obtain cheap renewable solar energy. However, characteristics of crystalline perovskite materials suitable for solar cells are not yet all clearly understood. In this thesis was studied and optimized the preparation of perovskite methylammonium lead tribromide (MAPbBr3) crystals using anti solvent vapor assisted crystallization (AVC). These crystals were prepared and studied in a small channel between two carbon electrodes on 3D printed substrate made from polylactic acid (PLA) connected to a larger electrode system were measuring took place. Electrical properties of prepared crystal structures were studied using current voltage characteristic and the process of crystallization was documented. Crystal prepared by AVC method achieved sizes larger than 0,5 mm, their electrical conductance increased with their size and the crystals were photo and thermal sensitive. During crystallization of MAPbBr3 precursors from solution was found that a certain structural change exhibiting an increase in electrical conductance takes place in the presence of MABr. The setup of PLA substrate and measuring electrode system creates great opportunities for study of other perovskite materials and may be able to uncover some of the mysteries that these fascinating materials hold.
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English counterparts of Czech finite subjectless clauses
Pospíšil, Jan ; Malá, Markéta (advisor) ; Šaldová, Pavlína (referee)
The thesis focuses on the English counterparts of a Czech clause type which does not exist in English - finite subjectless clauses. These Czech clauses with a verbal or verbo-nominal predicate correspond to English clauses with a subject and a predicate. The thesis describes the repertoire of means used as subjects of the English constructions, also examining the factors which influence the choice of a particular subject and predicate, and the structure of the English sentence. The most influential factors are linked with the semantic class of the clause, i.e. whether it refers to the states of the surrounding environment or physical and psychical states, whether a general human agent is implied, or whether the meaning of the clause is associated with modality. The material is extracted from the Czech-English parallel corpus InterCorp. One hundred examples of Czech finite subjectless clauses were obtained from Czech original texts (the "core" texts). The clauses extracted comprise predicates which include the third person singular of an active past participle, i.e. Setmělo se. Došlo k nedorozumění.
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Study of transistor properties with ionic liquids
Mitáčková, Martina ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This diploma thesis is focused on the study of electric and dielectric properties of transistors based on ionic liquids. The measurements were performed on organic electrochemical transistors with a semiconducting channel made of PEDOT:PSS, which were firstly prepared on ITO substrates, later they were printed using 3D print. Ionic liquid NO4 (1-butyl-3-methylimidazolium hydrogensulfate) was used for measuring of the properties. Electrical properties were determined by measuring volt-ampere characteristics, dielectric properties were measured by impedance spectroscopy.
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Study of Electric Properties of Electrochemical Transistors with Ionic Liquids
Blahut, Jan ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor’s thesis is focused on preparation of organic electrochemical transistors and following characterization of electric properties of these systems. Two types of electrode systems were used for preparation – glass substrates with steamed oxide of indium and tin and polylactic acid substrates with admixture of carbon soot. Three methods were tested for creation of PEDOT channel. Materiál printing, spin-coating and manual application. The measurement shows, that voltage applied to gate electrode has no effect switching of transistor. Size and polarity of current between source and drain electrodes has a major influence here.
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Study of electrical and dielectric properties of perovskites
Moravčík, Marek ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
This bachelor’s thesis is focused on a study of electrical and dielectrically properties of perovskite single crystal prepared by inversed temperature crystallization. Measurement was done on sample of MAPbBr3. First the temperature dependences of current-voltage characteristics were measured, they help to determined Arrhenius dependences. Activation energies were determined from Arrhenius dependences for every single voltage. These activation energies were used to determined position of Fermi level during thermodynamic balance. Concentration of state for dominant energies and charge carrier mobility (drift, microscopic) were determined from current-voltage characteristics for constant temperature. Relative permittivity was used to determine these parameters from impedance measurement.
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Czech Drama in Early Modernism: The Portrayal of Leaders
Pospíšil, Jan ; Vojtěch, Daniel (advisor) ; Sílová, Zuzana (referee) ; Topolová, Barbara (referee)
The thesis constitutes the analysis of selected Czech dramas from the beginning of the 20th century representing various portrayals of national leaders. In my view, the dramas are Apollonian images of a kind representing the dreams of their creators about the strength and greatness, both individual and national. That is because, on one hand, the national leader is an exceptional individual, an exquisite human specimen and as such he or she corresponds to Nietzsche's characterization of a tragic hero as the highest phenomenon of the will. But at the same time, he or she is a national educator. Individual works represent various forms of how the leader educates and edifies the nation and whether he or she leads by command or by example. The dramas show us the leaders, who not only tame, purify, but also urge to growth those, whom they lead. The approach of the Czech playwrights is essentially mythopoetic. Their works constitute contributions to the creation or re-creation of national mythology, in other words, they deal with the meaning of the existence of the nation, or the national condition. They represent a dialogue or a polemic with one particular national mythology formed at the time that of T. G. Masaryk as he stated it in his works Česká otázka (1895), Naše nynější krise (1895), and Jan Hus...
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