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Observation of Insulators in ESEM
Matějka, Milan ; Špinka, Jiří (referee) ; Jirák, Josef (advisor)
This graduation theses in introduction deals with principle and problems of electron signal detection in scanning electron microscopy and charging of insulating specimens in SEM. The experimental part of the thesis describe the methods of qualification and quantification of insulating specimen charging effect observed in environmental scanning electron microscope through the use of ionisation and scintillation detector in dependence on water vapour pressure in specimen chamber. The goal of the thesis is formation of the methodics useful to evaluate charging effect at insulating specimens observing and on the basis of measuring, determine optimal conditions for insulating specimen observation with ionisation and scintillation detector.
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Method of Voltage Contrast in ESEM
Buchta, Michal ; Černoch, Pavel (referee) ; Jirák, Josef (advisor)
This graduation thesis deals with the problem of voltage contrast in ESEM. The purpose of this work was to verify influence of used detectors in the dependence on conditions in specimen chamber on the size of voltage contrast. With the conditions in specimen chamber we understand pressure and working conditions of signal detection. We used power transistor as specimen.
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Evaluation of structures of solder joint with printed board circuit
Jakubec, Jiří ; Jirák, Josef (referee) ; Černoch, Pavel (advisor)
The theoretical part of the diploma thesis deals with the basic principles of the scanning electron microscope and the environmental scanning electron microscope. A description of the signals generated by an electrons incidence onto a specimen and detection options of these signals in the mentioned microscopes is included in the work. The experimental part of the work concerns an examination of a quality of several joints soldered by different methods on the printed circuit boards after different stresses by use of a visual check and the instruments of the light microscope and the environmental scanning electron microscope. The acquired data are evaluated and summarized.
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Logistic process optimization in expedition of electrical enterprise
Reboková, Lenka ; Jirák, Josef (referee) ; Špinka, Jiří (advisor)
Logistics as a process of planning, realization and controlling of effective and powerful workflow and commodities warehousing, services and related information with the goal of costumers satisfaction, became highly important and inseparable part of every company. The essential part of the planning process is an analysis of the current company situation, which tries to find all the limiting factors, and which serves as a basis for the process of making a company more effective. This diploma thesis analyses the current state of the expedition division of the ModusLink Czech Republic s.r.o. company – it analyses all its working operations in detail and using chronometrical analysis method evaluates division‘s theoretical and feasible throughput capacity. The feasible throughput capacity is then confronted with division’s real throughput capacity achieved during the monitored months, and depending on the results of the comparison there are some conclusions and recommendations for future improvements mentioned.
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Optimalizace detekce sekundárních elektronů segmentovým ionizačním detektorem v environmentálním REM
Černoch, P. ; Jirák, Josef
The article deals with a prezentation of results of optimization of secondary electron detection by an ionization detector in the environmental scanning electron microscope. The ionization detectors consisting of a varied electrode geometry and varied voltages on these electrodes, named segmental ionization detectors, are presented as a possibility to reach desired contrasts in a specimen image. In this work, images acquired by several detectors demonstrate detection of different types of signal electrons utilizing a specimen containing thin surface layers and a specimen made for a material contrast measurement.
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Detekce signálu segmentovým ionizačním detektorem
Černoch, P. ; Jirák, Josef
This article deals with signal detection by a segmental ionization detector. Changes of image contrasts in a dependency on different potentials on electrodes of the segmental ionization detector are studied. Electron trajectories in an electrostatic field in a vacuum simulated via program Simion 3D 7.0 are considered during the experiment.
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