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Characteristics of semiconductor BSE electron microscope detector
Plot, Vítězslav ; Hubálek, Jaromír (referee) ; Boušek, Jaroslav (advisor)
The thesis deals with the characterization of a semiconductor detector of backscattered electrons. The theoretical part describes two types of electron microscopes, the interaction of the primary beam with the sample and individual types of electrons and radiation arising during the interaction. The most used types of electron detectors in scanning electron microscope are summarized. The basic characteristics of the semiconductor backscattered electron detector and their measurement methods are described. The experimental part deals with measuring the characteristics of the detector made by Delong Instruments and comparing it with commercially available detectors. Volt-ampere characteristic and dark current, the dependence of the gain on the accelerating voltage, as well as the time response of the detector were measured.
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Electro-Magneto-Hydrodynamic Model for Electron Microscopy
Mačák, Martin ; Horák, Vladimír (referee) ; Uruba, Václav (referee) ; Vyroubal, Petr (advisor)
This dissertation thesis deals with the description and development of an electromagneto-hydrodynamic model intended for electron microscopy. The basis of the work lies in the description of characteristic phenomena taking place in electron microscopes with a focus on environmental electron microscopy. The work dealt with a description of the electromagnetic field, supersonic flow of rarefied gas and a motion of relativistic charged particles in a gaseous environment. An electromagnetic model based on the definition of electric and magnetic vector potential was presented and was used for a simulation of an electromagnetic coil. The supersonic flow of a rarefied gas was defined by Navier-Stokes equations. In order to extend their application to low pressures, the boundary conditions for velocity and temperature were modified. Viscosity and thermal conductivity were subsequently introduced as functions of gas pressure. These adjustments were able to describe the effects of lower collision frequency of gas particles. The presented model was used for the analysis of a flow through a separate aperture and a differentially pumped chamber. Furthermore, the model and necessary adjustments for the description of relativistically moving particles were presented. The model was used for the simulation of electron optics. Separate attention was paid to the interaction of charged particles with a gaseous environment. These interactions had a stochastic character and the presented model described both elastic and inelastic collisions. The presented multiphysics model enables the simultaneous simulation of different physical areas and the interactions between them, which leads to a possibility of a more detailed description of processes and to the improvement of environmental electron microscope design.
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Bearing diagnosis of electrical motors
Kratochvíl, Lumír ; Janda, Marcel (referee) ; Vítek, Ondřej (advisor)
This work breaks down the individual phenomena and findings that have as a common denominator the emergence of irreversible processes leading to damage to bearings in electrical machinery and equipment. The introduction describes the basic description and division of bearings with the recommended methods of their basic operation. The following chapters then deal with the individual sources of damage, diagnostics of individual damages, or examine in more detail the accompanying phenomena of bearing damage. In the first practical part of the work, damaged bearings are physically analyzed and their diagnostics is performed on an electron microscope. The second part of the work deals with vibrodiagnostics and the use of appropriate methods to determine the condition of the rolling bearing and then the location of the source of vibration at error frequencies.
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Electrohydrodynamic Model Of Electron Microscope
Mačák, Martin
This work presents a complex multiphysics model of an electron microscope in ANSYSFluent software. A custom electromagnetic model was used to describe the relativistic transport ofelectrons. The model consisted of a description of an electromagnetic field, relativistic transport ofcharged particles and interactions between charged particles and solid materials. Presented resultssuggest, that the custom model can be coupled with the CFD module, which results in a possibilityof coupled simultaneous simulations of hydrodynamics, electromagnetics, and a transport of chargedparticles.
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Ray Tracing for Electron Microscope
Suchánek, Jan ; Lysek, Tomáš (referee) ; Čadík, Martin (advisor)
This thesis is pointed on simulation of electron microscope. It uses knowledge from ray-tracing methods and physically based rendering with physics of electron microscopy. The main object of this thesis is to create realistic simulator for electron microscope which can generate satisfying realistic images. This output can be used for another research in range of machine learning or microscope application development. This method should replace long and more expensive way of getting test images from real system for those research activities.
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Conceptual design of a precision manipulator
Stuchlík, Petr ; Pavlík, Jan (referee) ; Vetiška, Jan (advisor)
This diploma thesis deals with the problems of analysis and the subsequent design of a precision manipulator used as a microscope table. The first part od the final thesis deals with the problems associated with the movement of the test sample within the electron microscope. Subsequently, possiblle design variants were proposed, further developing the next steps fot the correctness and functionality of manipulator. The individual force loads of the components were calculated. The result of the work was constructed as a CAD model with subsequent transfer to the assembly drawing.
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Modification of nanomanipulator used in electron microscope
Habarka, Ondrej ; Tkoč,, David (referee) ; Krejsa, Jiří (advisor)
Cílem této diplomové práce je zlepšit chování nanomanipulátoru, používaného v elektronovém mikroskopu, při vykonávaní nejmenších kroků pohybu. První částí je analýza mechanismu za účelem nalezení možných řešení problému. Dále se práce zabývá testováním řešení jako je optimalizace tuhosti předepínacích pružin mechanismu anebo změna mazání šnekového převodu mechanismu. Výsledkem práce je výběr nejvhodnějšího řešení problému na základě výsledků testů a následná modifikace nanomanipulátoru.
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