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Voltage contrast method in ESEM
Krňávek, Martin ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
This work contains theoretical description of basic features and principles of electron microscopy, with focus on environmental scanning electron microscopy. It describes function of the microscope, interactions that takes place after collision of electron pack with a sample, mainly it describes creation of back reflected electrons and secondary electrons and methods of voltage contrast. The practical part focus on voltage contrast issue by observing decomposition of electric potentials on surface of semiconductor devices and it establishes ideal working conditions for observing voltage contrast by scintillation detector of secondary electrons.
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Comparison of microscopic diagnostic methods
Veselý, Jakub ; Tihlaříková, Eva (referee) ; Čudek, Pavel (advisor)
This thesis deals with the description and comparison of diagnostic methods, transmission electron microscopy, scanning electron microscopy and atomic force microscopy. The introduction is a description of diagnostic methods. The following experimental section dealing with the diagnosis of ferritic chromium steel sample methods of scanning electron microscopy, atomic force microscopy, transmission electron microscopy and the evaluation and interpretation of measured results. The conclusion provides a comparison, the advantages and disadvantages of diagnostic methods.
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Analysis of active material for batteries by EDS
Vídeňský, Ondřej ; Jaššo, Kamil (referee) ; Čudek, Pavel (advisor)
This master thesis deals with analysis of battery mass using x-ray spectral microanalysis. For the measurement two scanning electron microscopes equipped with energy dispersive x-ray spectroscopes were used. Appropriate examples were prepaired by standard method. Then elemental analysis was performed with changing conditions of measurement. Two programs were used for spectrums evaluation and in the end the size of errors was observed for every conditions.
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Scintillation Secondary Electrons Detector for ESEM
Čudek, Pavel ; Kadlec, Jaromír (referee) ; Rek, Antonín (referee) ; Jirák, Josef (advisor)
The thesis deals with the scintillation secondary electron detector for environmental scanning electron microscope, its design and construction. The starting point was numerical simulation of electrostatic fields and electron trajectories in the electrode system of the detector and simulation of pressure distribution and flow of gases in different parts of the detector. On the basis of modeling and simulation, construction changes of the detector were gradually implemented. Detection efficiency of each version of the detector was determined by the method described in the work. This method enables to evaluate signal level from the captured images of the specimen, quality of images was stated from signal to noise ratio. The thesis describes the whole process of the detector improvement from initial state, when the detector operated with lower efficiency in the pressure range from 300 to 900 Pa, to final version that enables usage of the detector in the range from vacuum up to 1000 Pa of water vapors in the specimen chamber of the microscope.
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Influence of working conditions on the results of EDS in ESEM
Pospíchal, David ; Čech, Ondřej (referee) ; Čudek, Pavel (advisor)
The bachelor thesis deals with energy dispersion spectroscopy and detection of characteristic X-rays in the field of environmental scanning electron microscope. The aim of the semester work is to compare the results of elemental microanalysis of samples under optimal conditions and to monitor changes of results, when changing working conditions, resp. nitrogen and water vapor pressure in the sample chamber of the scanning electron microscope Vega3 XMU with LaB6 cathode. TESCAN, a.s equipped with Xflash 6 | 10 spectrophotometer. Bruker
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Comparison of microscopic diagnostic methods
Veselý, Jakub ; Tihlaříková, Eva (referee) ; Čudek, Pavel (advisor)
This thesis deals with the description and comparison of diagnostic methods, transmission electron microscopy, scanning electron microscopy and atomic force microscopy. The introduction is a description of diagnostic methods. The following experimental section dealing with the diagnosis of ferritic chromium steel sample methods of scanning electron microscopy, atomic force microscopy, transmission electron microscopy and the evaluation and interpretation of measured results. The conclusion provides a comparison, the advantages and disadvantages of diagnostic methods.
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Study of materials for the Li-ion batteries by electron microscopy
Hujňák, Jan ; Čudek, Pavel (referee) ; Kazda, Tomáš (advisor)
This work deals with problems of lithium-ion batteries. In the theoretical part are described electrochemical sources in general and their division. The main representatives of individual types of electrochemical sources are described in more detail. In the next part the thesis focuses specifically on lithium-ion accumulators, their history, electrochemical reactions taking place inside and materials of individual parts of which the accumulator consists. Next part focuses on electron microscopy and its division into scanning and transmission. Basic parts and the principle of operation are described. The practical part is focused on creating a small cell for examination under an electron microscope.
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Study of the electrode materials for Li-Ion accumulators by electron microscopy
Kaplenko, Oleksii ; Čudek, Pavel (referee) ; Kazda, Tomáš (advisor)
The aim of this work is to describe the influence of temperature on the structure and chemical composition of electrode materials for Li-ion accumulators. Theoretical part of this thesis contains described terminology and general issues of batteries and their division. Every kind of battery is provided with a closer description of a specific battery type. A separate chapter is dedicated to lithium cells, mainly Li-ion batteries. Considering various composition of Li-ion batteries, the next subchapters deeply analyzes the most used cathode (with an emphasis on the LiFePO4, LiMn1/3Ni1/3Co1/3O2) and anode materials (with an emphasis on the Li4Ti5O12). The next chapters describe the used analytical methods: electron microscopy, energy dispersion spectroscopy and thermomechanical analysis. The practical part is devoted to the description of the individual experiments and the achieved results.
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Ionization detector for environmental scanning electron microscope
Melechovský, Ondřej ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
Presented work deals with environmental scanning electron microscopy. The construction of the device is described concisely in the beginning. Important part is devoted to interaction of electrons with specimen and signals emitted from the specimen. The work aims especially at detection of secondary electrons using the ionization detector. Experimentally is determined effect of working environment and size of electrode system of ionization detector on detected signal.
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Contrast in image acquired by ionization detector in VP SEM
Goroš, Pavel ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
This work deal with problems of investigation materials electron beam. This project is focuses on investigation materials by the help of method environmental scan electron microscopy (ESEM) and describes her patterns. The perfection of ESEM excel above all at studies non - conducting or water containing, often biological samples. These samples not to be in no way prepared or cut – and – dries, in contradistinction to classical scanning electron microscope and thanks is under investigation their native surface structure without desiccation breaking. The general aim is determination of contrast in image acquired by ionization detector.
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