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Dynamic electroneurostimulation and electrical properties of skin
Špeta, Marek ; Dvořák, Petr (referee) ; Špinka, Jiří (advisor)
The focus of this diploma thesis is on theoretical basics of dynamic electroneurostimulation, which is an effect of electrical signal on acupuncture points of skin. This technology is used in devices made by russian DiaDENS company. Practical part of this thesis covers design of human skin impedance model. Especially derivation from three-element Cole-Cole model. Elementary, there is design of equivalent circuit of constant phase element and its incorporation into circuit. Then this circuit is designed, simulated and produced. Resulting product is used as a load to measure the characteristics of the DiaDENS device.
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Construction of an impedance analyzer
Slinták, Vlastimil ; Smékal, Zdeněk (referee) ; Mikulka, Jan (advisor)
The aim of this master’s thesis is to build stand-alone impedance analyzer for mesasuring antennas’ impedance. The vector network analysis is used as measuring method. Analog (with directional coupler and gain and phase detector) and digital (with 8bit AVR microcontrollers) part of analyzer are described and then build.
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Design and realzation of electric measurements on biological tissues
Kocová, Lucie ; Palai-Dany, Tomáš (referee) ; Tománek, Pavel (advisor)
This master’s thesis is focused on the electrical properties of biological tissues and flesh in particular. Their electrical characteristics depend on the physical and chemical parameters that determine the concentration and mobility of ions in metabolic fluids. From the electrical point of view, flesh can be simply substituted by a field of elongated conductive cells which are separated by the insulating membrane from each other. In the next part, the Fricke model is introduced. The model describes the measurement of impedance of the tissue at low and high frequencies. The aim of the work is to assess how the impedance of the dielectric sample is dependent on the frequency of the electrical signal during the optimal aging or ripening of flesh.
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Methods for properties analysis of transmission lines
Žůrek, Dalibor ; Kočiš, Luboš (referee) ; Hadinec, Michal (advisor)
This work focuses on a search of available literature on the theory of transmission lines and verify the possibility of simulation processes on these lines using a suitable simulation program. Initially, for the introduction to the parameters and the phenomenon that characterize the line and are important for understanding the issue. These parameters are then measured and compared with traces from the simulation in program PSpice. In another part of the work, the reader is familiar with the basics of reflectometry and fault detection capabilities on transmission lines with the basic reflectometry methods TDR and FDR, as well as with other methods of OTDR, MSR, and PD-FDR. For the TDR, FDR and MSR methods were made experimental measurements with a view to determining the position of the various types of faults on the tested leadership.
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Design of measuring solutions for circuits with differential signals
Jemelík, Lukáš ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This master´s thesis deals about a measuring structures of elements working at a current mode. There were outlined structures for measuring input and output impedance. These structures were simulated for DACA element. It deals with a voltage to current and current to voltage converters. All structures and converters were simulated at computer program PSpice. Selected variant were practically verified and control measuring was realized.
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Optoelectronic sensor of polarization state of light from biological samples
Mikláš, Jan ; Brüstlová, Jitka (referee) ; Tománek, Pavel (advisor)
The living body tissues consist of cells which dimensions are bigger than a wavelength of visible light. Therefore a Mie scattering of reflected of backscaterred light occurs and different polarization states arise. The changes of polarization state due to the multiple scattering of light in the biological cellular tissues allow measure the aging of biological tissue. The reflected or backscattered polarized laser light exhibits multiple scattering on the sample surface and in its subsurface area.
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Automatic antenna analyser
Dufek, Ivo ; Šebesta, Jan (referee) ; Lukeš, Zbyněk (advisor)
This project is dealing with methods of measuring impedances of the antenna systems in the frequency range from the low frequencies to the very high frequencies. There is a discussion about different methods of measuring impedance and each technique is critically evaluated. In terms of this project is compared few types of the professional antenna analyzers. According to this comparison there was made the concept of my own antenna analyzer. There is a detailed description of the design of this device’s important parts including software equipment. Designed instrument has been built and tested.
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Simulation of Effects of Short-circuit Currents in HV Switching Stations
Tománek, Miloslav ; Buriánek, Jiří (referee) ; Toman, Petr (advisor)
This thesis is engaged in a theoretical calculation of short-circuit currents in electric power system in compliance with the norm ČSN 60909-0 and first of all with calculation of dynamical and thermal effects of short-circuit currents in HV switching stations in accordance with the norm ČSN 60865-1. Next the thesis is engaged in a production of programs for simulation of mechanical effects of short-circuit currents with respect to a dimensioning of constructional elements of switching station and afterwards in a practical simulation of selected parts of the real switching station type „H“ in Slavkov u Brna.
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Computing directivity patterns in Comsol Multiphysics
Ryšánek, Martin ; Lukeš, Zbyněk (referee) ; Raida, Zbyněk (advisor)
The individual project – Computing directivity patterns in Comsol Multiphysics. In the first part, the theoretical background for monopole antennas is reviewed. The second part is focused on the analysis of several types of monopoles in COMSOL Multiphysics, and on the calculation of their radiation patterns and impedances. Finally, simulation results are presented and discussed.
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Stabilized operation of a 400 kV power line
Girga, Eduard ; Špaček, Jaroslav (referee) ; Blažek, Vladimír (advisor)
Electrical wiring 400 kV is the most used transfer wiring in the Czech Republic with length over three thousand kilometers. It is frequently used for running out significant output from the big power plants and for its significance in electrical engineering. Theoretical part of this thesis deals with the cross-section of mainly used methods for high and extra high stable wiring voltage solution. These methods can be generally dividend into precise and rough. Both of these methods will be analyzed in next chapters. Exact solution comes out from the presumption of equally spaced parameters. The rough solution uses substitution of double gates wiring, this method is accurate enough and accelerates the calculation. Former mentioned reasons explains it’s often use in technical practice. The electric line is substituted by T-cell, II-cell or Steinmetz cell according to length and required precision. Special method of rough solution is the broad method which enables to solve randomly knotted network by using II-cell to replace electric wiring between single knots. This method is mentioned in thesis for completeness; the network solved by me is not knotted. Part of the theoretical thesis is the analysis of specific transfer cases. In computing part will be mentioned not only the computation of stable wiring state with precise an rough method - with all former mentioned cell but the computation of specific transfer cases as well. In the end will be concluded all the counts from computing part and from precision view evaluated used methods of the stable wiring solution.
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