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Study of ferroelectric materials
Kos, Lukáš ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This work is focused on the study of perovskite ferroelectric materials group and monitoring changes their dielectric parameters in temperature and frequency dependence Is described scrystallographic systems of barium titanate and their influence on material properties. The measured values are mathematically interpreted using the Curie – Weiss law and discussed about the influence of strontium titanite on important dielectric parameters.
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Modeling of physical phenomena in semiconductors
Pálka, Mário ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
This work deals with properties and physical phenomena occurring in semiconductor materials. In details are described generation - recombination processes in a state of thermodynamic disequilibrium. The output of work is a software application simulating waveforms of energy levels in the band's own models and impurity semiconductors, depending on the type of semiconductor, impurities concentration and temperature. Finally, the processed virtual lab experiment deliverable in the educational process.
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Accuracy of the determination of liquid viscosity
Zikmund, Ondřej ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This master thesis is focused on the rheological properties of liquids, especially on the viscosity and the standard uncertainty. It explains methods of the viscosity measurement and the calibration selected viscometers, the principle of the determination of standard uncertainty by indirect measurement of the viscosity and the density. The main object of this thesis was to create a specialized centre for viscosity measurement and to create a document which could be used by teaching of diagnostics.
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Methodology for contactless measurement of temperature
Skalický, David ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This thesis deals with the issues of contactless measuring of temperatures and calibration of chosen temperature meter. The beginning of this thesis concerns physical laws and basic terms which are crucial for contactless measuring of temperatures. The following part gives the division of detectors and pyrometres for contactless measuring of temperatures. The conclusion of the theoretical part describes the advantages of these ways of measuring and practical use of them. The practical part deals with instruments that are accessible at Faculty of Electrical Engineering and Communication, their comparing and choice of the most advantageous meter for calibration. The following part is the implementation of the experiment related to contactless meassuring of temperatures. The conclusion of the practical part contains composition of optimized workplace for calibration of contactless temperature meters and the calibration of chosen temperature meters itself.
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Synergic effects of multistress ageing of electroinsulating materials
Novák, Lukáš ; Frk, Martin (referee) ; Rozsívalová, Zdenka (advisor)
Submitted work deals with monitoring impact of thermal and electric ageing on the dielectric properties of insulating material NKN 0887. In the course of the experiment five sets of dielectric insulating materials were aged. The voltage range has been set from 1,5 kV till 2,2 kV and temperatures were 23 °C and 200 °C. The capacity and loss factor has been directly measured by RLC meter Agilent with attached electrode system. The electrode system operates on the principle of a plate capacitor. The values of relative permittivity and loss number has been calculated from values of capacity and loss factor. For easier confrontation has been frequency dependences of these values plotted in a chart. The Cole-Cole diagrams has been created and factors of Havriliak-Negami function has been calculated. Data has been compared with each other and the effect of ageing factors has been deduced.
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Electrical conduction of alternative electroinsulating liquids
Reňák, Ladislav ; Rozsívalová, Zdenka (referee) ; Frk, Martin (advisor)
This labor deals with features of alternative electrical insulating liquids and also petroleum-base liquids. It examines their usage in the electrotechnical industry. The practical part of the thesis deals with measurement of absorption charakteristics of biodegradable electrical insulating liquid MIDEL 7131 and the petroleum - based transformer oil TRAFO N. The results of the measurement are examined by the help of substitutional math function.
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