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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.
121

Speciační analýza vybraných sloučenin rtuti pomocí HPLC, UV-fotochemického generování studené páry rtuti a její detekce AAS / Speciation Analysis of Selected Mercury Compounds Using HPLC, UV-Photochemical Cold Mercury Vapor Generation and its AAS Detection

Linhart, Ondřej January 2013 (has links)
The mercury occurs in the environment in a variety of forms. Mercury compounds can be found in the soil, atmosphere, water and living organisms. Although some of the mercury substances are very toxic, they are often used in various sectors of industry, agriculture and medicine. Mercury compounds differ in their toxicity, so it is necessary to do speciation analysis. The aim of this diploma thesis was to develop and validate a new analytical method for the determination of mercury compounds in different samples. This method involves the combination of high performance liquid chromatography, UV-photochemical cold vapor mercury generation and atomic absorption spectrometry. Effective separation of mercury(II), methylmercury(I), ethylmercury(I) and phenylmercury(I) ions and subsequent comparable efficient of mercury cold vapor generation from all of forms was achieved using these techniques. The reached detection limits were 8 µg l-1 , 31 µg l-1 , 16 µg l-1 and 38 µg l-1 . At the end of experimental work, the proposed method of RP-HPLC-UV-CVG- QTAAS was used for the determination of mercury compounds in real samples (fish tissue and water samples: Labe, Vltava and tap water) and in certified reference materials (DORM-3 and DOLT-4). Several methods for extraction of mercury species from solid samples...
122

UV-fotochemické generování těkavých sloučenin selenu a teluru / UV-photochemical generation of volatile compounds of selenium and tellurium

Nováková, Eliška January 2017 (has links)
The presented thesis deals with UV-photochemical generation of volatile compounds of Se and Te from various species. The aim of the project was to expand the current state of knowledge by the application of photocatalytic reduction of higher oxidation states of Se and Te for the speciation analysis based on UV-photochemical generation of volatile compounds. The first step of the study was the assembly of the apparatus for the photocatalysed UV-photochemical generation of volatile compounds. The material of reactor and the whole experimental set-up were based on literature survey and previous research done in our research group. Experiments were directed towards finding the optimum conditions for generation of volatile compounds of selected model elements Se and Te. Se was studied as the element most commonly determined by the UV-photochemical generation of volatile compounds. Conversely, Te was selected as a model analyte representing elements forming less stable volatile compounds. The second part was the application of the optimised method of photocatalysed UV- photochemical generation of volatile Se compound to the determination of Se in water matrices, liquid certified reference materials and also samples of dietary supplements. TiO2/UV-photochemical generation was also successfully modified to...
123

Mechanismus atomizace vybraných hydridotvorných prvků ve vyhřívaném křemenném atomizátoru a plazmovém atomizátoru s dielektrickou bariérou / Mechanism of atomization of selected hydride forming elements in an externally heated quartz tube atomizer and a dielectric barrier discharge atomizer

Juhászová, Lucie January 2019 (has links)
Atomization conditions for tin hydride in the planar dielectric barrier discharge (DBD) plasma atomizer were optimized with detection by atomic absorption spectrometry (AAS). The effects of apparatus arrangement such as the shape of a waveform function of the high voltage power supply source, DBD atomizer design as well as presence of a dryer tube filled with NaOH pellets to prevent residual aerosol and moisture transport into the DBD were investigated in detail. The optimal experimental setup consisted of a square wave high voltage power supply source coupled to a DBD with vapor-deposited electrodes in the presence of NaOH dryer upstream the DBD atomizer. Argon was found as the best discharge gas under a flow rate of 120 mL min-1 while the DBD optimum high voltage supply rate was 7 kV. A sensitivity of 0.05 s ng-1 Sn and a limit of detection of 1.1 ng mL-1 Sn were reached under optimized conditions. Optimization of the whole experimental setup resulted in 7-fold improvement of sensitivity compared to the original arrangement consisting of a sinusoidal source coupled to a DBD atomizer with glued electrodes in absence of the dryer. Keywords atomic absorption spectrometry, hydride generation, hydride atomization, quart tube atomizer, dielectric barrier discharge (DBD)
124

Generování hydridu bismutu pro atomovou absorpční a fluorescenční spektrometrii. / Hydride generation of bismuth for atomic absorption and fluorescence spectrometry.

Kolrosová, Marta January 2019 (has links)
This master's thesis deals with the optimization of conditions of chemical hydride generation (HG) of bismuth, its atomization and detection by atomic absorption spectrometry (AAS) and atomic fluorescence spectrometry (AFS). Two types of atomizers were used for atomization of volatile species, a miniature diffusion flame for AAS as well as for AFS and a flame-in-gas-shield atomizer for AFS. At first, the parameters of HG in a flow injection mode were optimized - the concentration of hydrochloric acid, the concentration of sodium borohydride and the volume of the reaction coil. Subsequently, the atomization conditions were optimized using both atomizers. The parameters optimized were hydrogen fraction, total gas flow rate and observation height. Due to the more complicated construction of the FIGS atomizer, more parameters were studied, such as the oxygen flow rate through the capillary and the flow rate of shielding argon required for shielding the free atoms. A special part of the thesis dealt with the optimization of the optical path of the atomic fluorescence spectrometer, the selection of an interference filter and the optimization of a power supply of an electrodeless discharge lamp. It was found that under optimum conditions of generation, atomization and detection excellent detection limits...
125

Generátor otisků prstů / Fingerprints Generator

Chaloupka, Radek Unknown Date (has links)
Algorithms for fingerprints recognition are already known for long time and there is also an effort for their best optimization. This master's thesis is dealing with an opposite approach, where the fingerprints are not being recognized, but are generated on the minutiae position basis. Such algorithm is then free of the minutiae detection from image and enhancements of fingerprints. Results of this work are the synthetic images generated according to few given parameters, especially minutiae.
126

Informační systém pro školy s automatickou tvorbou rozvrhů / Information System for a School Including Automated Timetabling

Švadlenka, Jiří January 2008 (has links)
This thesis devote itself to use of information system for school agenda administration. Schools are forced to administer big amounts of informations, not only referred to their students. Broad issue is very extensive and disparate, so the most common types of data and demands on school information system operation are stated. The system for automatic generation of timetables is part of the school information system. At the first, basic conceptions of scheduling scope are defined and tied together with them are methods and algorithms for timetable creation problem solving. School timetabling is problem of scheduling lessons with certain limitative conditions. Further, thesis is engaged in design of school information system, data organization in such system and solving of system design problems. Designed information system accentuates on easy expandability and wide range of usage possibilities. Also suggested algorithm for solving of defined school timetabling is stated in this part of thesis.
127

Realistická krajina s vegetací / Realistic Landscape with Vegetation

Zelený, Jan January 2009 (has links)
There is enough rendering power to draw more than only simple indoor scenes today and it can produce very realistic images of landscape with vegetation. Moreover, there are new sophisticated methods for generating of such landscape and simulation of plants ecosystem. This text explains few algorithms for generating and methods for interactive rendering of landscape and vegetation.
128

Generování herního prostředí na základě hudby / Game Environment from Music

Vaněk, Jiří January 2009 (has links)
The topic of this work is game environment generation from music. The main subject of this work is the music analysis. I am dealing with the problem of finding relevant information in music, which would be useful for game generating. The design of the system for music analysis, presented in this work, is based on the theory of signal processing and statistical classification. The proposed analysis of music is focused mainly on a beat detection, musical genre recognition and song segmentation. The second part of the work deals with the design of a game, which generates its environment from the data obtained in the music analysis. I have implemented the complete system for the music analysis and a prototype of the game, in which it is possible to evaluate the results from the analysis. The implementation and the achieved results are described in the conclusion of this work.
129

Grafické intro 64kB s použitím OpenGL / Graphics Intro 64kB Using OpenGL

Gunia, Pavel Unknown Date (has links)
This work deals with the phenomenon of graphic intros, a digital graffiti of the modern age. The focus is put on size restricted animation of size of the executable file lower than 64 kilobytes. It reveals the main techniques used. Finally, interesting aspects and experiences that came up are discussed, as well as the conclusion and future work proposal.
130

Vyšší vrstvy a rozhraní pro knihovnu generující grafy / High Layers and Interface for Graph Library

Studený, Tomáš Unknown Date (has links)
This work deals with problems of easy web graph generate. Project implement user-friendly interface for Object-Oriented Graph creating library pChart.

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