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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Využití uživatelské odezvy pro zvýšení kvality řečové syntézy / Improving text-to-speech in spoken dialogue systems by employing user's feedback

Hudeček, Vojtěch January 2017 (has links)
Although spoken dialogue systems have greatly improved, they still cannot handle communications involving unknown topics. One of the problems is, that they experience difficulties when they should pronounce unknown words. We will investigate methods that can improve spoken dialogue systems by correcting the pronunciation of unknown words. This is a crucial step to provide a better user experience, since for example mispronounced proper nouns are highly undesirable. Incorrect pronunciation is caused by imperfect phonetic representation of the word. We aim to detect incorrectly pronounced words, use knowledge about the pronunciation and user's feedback and correct the transcriptions accordingly. Furthermore, the learned phonetic transcriptions can be added to the speech recognition module's vocabulary. Thus extracting correct pronunciations benefits both speech recognition and text-to-speech components of the dialogue systems.
152

Využití organokatalýzy založené na tvorbě H-vazeb v organické syntéze / Application of H-Bonding Catalysis in Organic Synthesis

Urban, Michal January 2020 (has links)
Over the last 20 years, asymmetric synthesis has seen considerable progress, particularly in the field of catalysis. In addition to enzyme catalysis and transition metal catalysis, organocatalysis, catalysis using small organic molecules also plays an important role in the asymmetric synthesis. Chiral organocatalysts allow the preparation of structurally interesting and optically pure molecules via various activation modes. This work is focused on the use of organocatalysis based on the formation of hydrogen bonds in organic synthesis. Our study was devoted to the enantioselective organocatalytic reactions of ketimines leading to the formation of chiral vicinal centers. The first part deals with the organocatalytic enantioselective addition reaction of α- fluoro(phenylsulfonyl)methanes to ketimines derived from isatin. The reaction utilizes catalysis of a commercially available quinoline alkaloid cinchonine. A series of enantiomerically pure compounds were prepared containing two neighboring stereocenters in good yields of up to 97%, with diastereoselectivity up to 6: 1 dr and with enantiomeric excesses of 70-98% ee. In most cases pure diastereomers were obtained. In the second part of the work a method of enantioselective orgnocatalytic synthesis of bis-spirocompounds containing two neighboring...
153

Příprava rekombinantního cytochromu P450 1A1 / Preparation of recombinant cytochrome P450 1A1

Dvořák, Martin January 2011 (has links)
5 Abstract Cytochrome P450 1A1 (CYP1A1) is one of the major isoforms of the cytochrome P450 superfamily. It is primarily an extrahepatic enzyme which is responsible for oxidation of many polycyclic aromatic hydrocarbons and other xenobiotics. Besides of the role in detoxification metabolism CYP1A1 is the one most important isoform involved in activation of procarcinogens. The main aim of this project was preparation of two modifications of the rat CYP1A1 gene with codon optimization for expression in E. coli by gene synthesis. One was wild type (wt1A1) and the other was with modified N-terminal anchor (mod1A1) - for both modifications with or without His Tag at the C-end of CYP1A1. Furthermore, an aim was to compare their level of expression in different strains of E. coli and try to purify and assess enzymatic activity of the gene's products. From pre-prepared oligonucleotides 2 "syntons" (parts of gene) were synthetized and separately inserted into pUC19. After verified sequence of the "syntons" they were cleaved from pUC19 and inserted together into pET-22b. These vectors were prepared for transformation of 3 strains of E. coli (BL-21 (DE3) GOLD, RIL a RIPL). For production of proteins many conditions were tested: temperature (18, 22, 24, 27 a 37 řC), time of production (untill 48 hours), concentration...
154

Příprava a charakterizace nanomateriálů obsahujících sloučeniny bóru / SYNTHESIS AND CHARACTERIZATION OF NANOMATERIALS CONTAINING BORON COMPOUNDS

Vrbata, David January 2021 (has links)
This thesis is focused on synthesis and polymerization of caprolactone and its derivatives by living ring opening polymerization (LROP), Self-assembly in aqueous solutions produced nanoaggregates comprised of amphiphilic block copolymers or telechelic polymers with incorporated boron compounds (phenyl boronic acids and boron clusters). Incorporation of boron compounds was facilitated either by covalent or non-covalent bonding. Obtained complex nanoparticle structures manifested stimuli-responsive behaviour and were investigated under varying conditions by combination of light scattering, fluorescence spectroscopy and electron microscopy. The obtained results on solution behaviour of polymers in combination with added value of boron compounds, yield general aspects of nano aggregate morphology, responsive character tuning and practical aspects of synthesis and self-assembly overcame in the preparation process. The publications wrote during this thesis are therefore adding valuable information to researchers engaged in biomedical utilization of such nano assemblies.
155

Studium katalytické aktivity keramických perovskitových materiálů pro energetické aplikace / Study of catalytic activity of ceramic perovskite materials for energy applications

Schlosser, Radek January 2011 (has links)
In this diploma thesis the preparation of ceramic catalytic materials was studied. They were studied by means of catalytic activity on powder samples and in a form of membrane as well. At first were multicomponent perovskite materials with the help of “glycine-nitride synthesis” synthesized. Two types of perovskite systems were prepared. First system was on the basis of nickelates LaNiO3 and the second one on the basis of cobaltites SmCoO3. Both of them were doped with aluminium and calcium. Ceramic powders were catalytic tested during reformed reaction. A part of powders was pressed with hydraulic biaxial press. Then the membranes were calcinated, sintered and polished. The membranes were tested to specify the catalytic activity. At first they were in hydrogen atmosphere reduced and afterwards came through the partial oxidation. The appearance of coke fibers on the surface was discussed.
156

APLIKACE NANOMATERIÁLŮ PRO VÝVOJ PÁJEK BEZ OLOVA / THE APPLICATION OF NANOMATERIALS FOR LEAD FREE SOLDERS DEVELOPMENT

Pešina, Zbyněk January 2012 (has links)
The present dissertation is motivated by the search for alternatives of lead-free soldering by nanoparticles of metals and their alloys. The research focuses on the possibility of replacing lead-free solders by nanoparticles. This issue is currently being addressed by the use of lead-free solders but their properties are not entirely equivalent to properties of lead-tin based alloys. The theoretical part of the dissertation first summarizes up-to date knowledge on the development of lead-free alloys currently used for soldering in the electronics. The work compares these lead-free solder candidates with previously used Pb-Sn alloys. The second section of the theoretical part is devoted to nanotechnology that offers possible solutions of problems associated with the use of lead-free solders. The text contains a description of the properties of nanocrystalline materials in comparison with those of compact alloys having the same chemical composition. The possibility of preparation of nanoparticles and potential problems associated with small particle sizes are also presented. Introduction of the experimental part focuses on the preparation of nanoparticles of pure metals and alloys by chemical and physical ways as well as on an instrumentation for characterisation and analysis. Attention is focused on the silver in nanoparticle form that exhibits the low temperature sintering effect, which is thermally activated by decomposition of oxide envelope covering the Ag nanoparticles. This factor is critical for low-temperature sintering and thus also for possible future applications. The thermal effects of the low sintering process were studied by methods of thermal analysis. The preparation of the Cu / Ag nano / Cu joints was carried out in-situ in inert atmosphere and under the action of atmospheric oxygen. In both cases varying conditions of thermal treatment were used. The cross sections of the prepared joints were then used for the metallographic analysis of the local mechanical properties of the resulting silver layer, for the chemical composition evaluation of the resulting layers of the joint, and for the microstructure study. Strength characteristics are represented by testing shear strength of individual joints.
157

Zdroj pro pulzní magnetronové naprašování / Power source for pulse magnetron sputtering

Schulz, Jakub January 2008 (has links)
The presented thesis deals with the design and assembly of the generator for pulse magnetron sputtering. The designed device is capable of generating two square wave signals via its counter-working outputs. Both signals have independently adjustable frequency, pulse count and duty ratio. Both signals originate from two frequency syntheses controlled by microcontroller PIC16F877A. All the settings are entered by four buttons and are shown on an alphanumeric display with 16x4 characters. The duty ratio is adjusted using a special module.
158

Role kresby postavy v Orientačním testu školní zralosti / Role of human figure drawing in Indicative test of school maturity

Michálková, Anna January 2017 (has links)
The thesis studies the role of human figure drawing in Orientační test školní zralosti (i. e. Jirasek's Orientation Test of School Readiness). The starting point is the correspondence between human figure drawing and other tasks in both verbal and non-verbal thinking. For the empirical material we have chosen pre-school children results in Orientační test školní zralosti, including the verbal thinking test and Raven's Coloured Progressive Matrices. The aim is to examine correspondence of human figure drawing with other tasks taking into account verbal and non-verbal thinking and logical and infralogic operations. The data was collected in two stages with the interval of four months and therefore it is able to assess durability of findings in time. The thesis is beneficial in terms of qualitative analysis of discovered correspondences and also in developing a theory of abilities tested by the test, especially regarding human figure drawing. Last but not least it is helpful in examining similarities and differences in the ability of children to analyse and synthetize. KEY WORDS: school maturity, drawing, figure, man, writing, points, matrices, verbal thinking, non-verbal thinking, logical operations, infralogic operations, analysis, synthesis
159

Syntéza kvantových teček pro in-vivo zobrazování / Synthesis of quantum dots for in-vivo imaging

Ferdusová, Helena Unknown Date (has links)
The aim of this work was to synthesise water-soluble QDs using different precursors and stabilizers and to determine the toxicity of the synthesized QDs by in vivo imaging. Experiments were performed on water-soluble QDs (MPA-CdTe, MPA-CdTe/ZnS, MSA-CdTe, MSA-CdTe/ZnS, GSH-CdTe, GSH-CdTe/ZnS, TGA-CdTe, TGA-CdTe/ZnS, GSH-ZnSe and GSH-ZnSe/ZnS ) and toxicity was measured. Synthesized QDs were characterized by high intensity (fluorescence spectroscopy), FWHM and zeta potential (ZS Zetasizer) were selected due to their suitability for this task. The toxicity of QDs was determined by the MTT assay on the cell line HEK 293. The experiments show that a core/shell structure is less toxic than a core structure. The results indicate that the toxicity of our synthesized QDs is the lowest for MPA-CdTe (core structure) and MPA-CdTe/ZnS (core/shell structure).
160

Strojový překlad a strojové tlumočení / Machine Translation and Machine Interpreting

Skadchenko, Yulia January 2019 (has links)
This thesis aims to provide an in-depth overview of machine translation and machine interpreting, describing their history, development, and current state, as well as their place on the market and their potential use. The thesis describes machine translation and machine interpreting on theoretical, practical, and technological level, including the description of their basic principles, evaluation criteria, obstacles and challenges, and scope of their use. The thesis also includes a practical test of one of currently available machine interpreting programs - Skype Translator by Microsoft. The aim of the test is to determine whether the program can facilitate successful communication between two people who don't speak the same language, and to describe the user's experience. Keywords: machine translation, machine interpreting, machine translation limitations, neural translation, Skype Translator, STACL, speech recognition, speech production

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