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Structure defects in SiC radiation detectors
Zetek, Matyáš ; Belas, Eduard (advisor)
Silicon carbide (SiC), is a wide band gap (2.4 eV < Eg < 3.3 eV) semiconducting material well known for its potential applications in high-temperature, high-power, high-frequency or hard radiation resistant devices. In this thesis, we are broadening elementary knowledge about this material. We identify energy levels in the material, using Photo-Hall effect spectroscopy supported by the temperature dependency of classic Hall effect measurement and temperature dependent photoluminescence. This knowledge is essential to allow SiC application as a radiation detector.
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Thermo-transport effects in antiferromagnets
Baďura, Antonín ; Schmoranzerová, Eva (advisor) ; Martins Godinho, João Pedro (referee)
This thesis investigates magnetic properties of an antiferromagnet Mn5Si3 in both collinear and noncollinear antiferromagnetic phases, which this compound evinces. The work is based on three distinct experimental approaches: The first one comprises mea- surements of magnetotransport phenomena (namely anisotropic magnetoresistance and Hall effects), the second one studies thermal counterparts of these effects (particularly the anomalous Nernst effect). Finally, we used scanning thermal gradient microscopy in order to observe the domain structure of Mn5Si3. The key outcome of the magnetotransport measurements is an observation of the Hall response in the collinear antiferromagnetic phase, which we attribute to the recently proposed crystal Hall effect. Furthermore, the thermotransport measurements resulted in the first observation of the anomalous Nernst effect in this compound. Due to the variety of artefacts, we did not record any convincing image of the domain structure in Mn5Si3. The analysis of the artefacts was supported by mathematical modelling that helped to pinpoint their origin.
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Utilization of artificially created weak magnetic field for navigation in 3D space
Váňa, Dominik ; Beneš, Petr (referee) ; Havránek, Zdeněk (advisor)
This master's thesis focuses on the utilization of an artificially created weak magnetic field for navigation in 3D space. The theoretical part of this work deals with the general properties of the magnetic field and with its description. The next section of the theoretical part contains an overview of measuring principles for magnetic field measurements. Based on various types of measuring principles, the thesis elaborates on commercially available miniature sensors for magnetic field measurement with a measuring range up to 10 mT. The work focuses mainly on the magnetoresistive principle and fluxgate sensors. Furthermore, the theoretical part contains descriptions of methods for modeling the magnetic field of simple permanent magnets and various magnet assemblies. Lastly, the theoretical part involves a patent search of devices used for locating magnets that are installed in an intramedullary nail, which is used in intramedullary stabilization used on fractures of human bones. By locating the magnet in the nail, it is possible to precisely determine the position of the mounting holes. The practical part of the thesis deals with the analysis of magnetic field behavior in the vicinity of various magnetic assemblies, which were modeled in COMSOL Multiphysics using the finite element method. The models were created with the aim of analysing the behaviour of the magnetic field in the vicinity of the magnets and at the same time to find possible analytical functions that could be used to determine the position of the magnet in space relative to the probe. The result of this work is an analysis of various assemblies, which contains graphs of different dependencies and prescription of polynomial functions that approximate these dependencies. Another part of the thesis is the design of a probe that serves to locate the magnetic target. The work describes two possible methods of localization. For the differential method, a user interface in LabVIEW was created. The probe based on this method is fully capable of locating the magnet in the 2D plane. The state space search method is described only in theory.
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Structure defects in SiC radiation detectors
Zetek, Matyáš ; Belas, Eduard (advisor)
Silicon carbide (SiC), is a wide band gap (2.4 eV < Eg < 3.3 eV) semiconducting material well known for its potential applications in high-temperature, high-power, high-frequency or hard radiation resistant devices. In this thesis, we are broadening elementary knowledge about this material. We identify energy levels in the material, using Photo-Hall effect spectroscopy supported by the temperature dependency of classic Hall effect measurement and temperature dependent photoluminescence. This knowledge is essential to allow SiC application as a radiation detector.
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Structure defects in SiC radiation detectors
Zetek, Matyáš ; Belas, Eduard (advisor) ; Hazdra, Pavel (referee)
Silicon carbide (SiC), is a wide band gap (2.4 eV < Eg < 3.3 eV) semiconducting material well known for its potential applications in high-temperature, high-power, high-frequency or hard radiation resistant devices. In this thesis, we are broadening elementary knowledge about this material. We identify energy levels in the material, using Photo-Hall effect spectroscopy supported by the temperature dependency of classic Hall effect measurement and temperature dependent photoluminescence. This knowledge is essential to allow SiC application as a radiation detector.
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Design and implementation of encoder unit
Kirchner, Tomáš ; Sova, Václav (referee) ; Spáčil, Tomáš (advisor)
The aim of the thesis is to implement an absolute magnetic encoder unit as a sensor measuring the angle of rotation of a DC engine on a ballbot, which is part of the BB-8 project at the mechatronic laboratory. It describes the principals and limitations of a magnetic encoder technology, also the design of printed circuit board for the sensor and the engine housing. Testing functionality of the encoder at Raspberry Pi was part of the work as well as creating SPI communication with a master microcontroller PIC. Furthermore an accuracy of the angle of rotation sensing was measured for different inaccuracy of a magnet position to the sensor.
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Design and realization of the power meter with IoT connectivity
Zagrapan, Ivan ; Lattenberg, Ivo (referee) ; Krajsa, Ondřej (advisor)
This thesis deals with designing and creating working prototype of IoT Wattmeter with option to switching relay. This device can be control remotely with option to read measured values. To reach my goals, I am using open-source designing board, different sensors and modules. I tis possible to communicate with device through Wi-Fi module ESP 8266 and to test LPWAN network I am using SIGFOX, module. To measure current, it´s used simple Hall-effect sensor and all available information’s are displayed on OLED display. To switch the circuit off or on solid state relay was used. In theoretical part of the work, I am trying to explain working principles of every module and source code, which I am using to control these modules. In practical part I created scheme, using CADSoft EAGLE and created functional wattmeter. Whole work is programmed in C++ language using Arduino IDE.
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Magnetic field meter
Rejnuš, Milan ; Hadinec, Michal (referee) ; Friedl, Martin (advisor)
This thesis summarizes well-known methods of magnetic fields and quantities. Particular methods and their principles are discussed and problems at usage are described as well. The proposal of laboratory product construction for teaching of subject Electrical engineering 1 is first part of the thesis. It is a case of magnetic measurement in the gap of the core excitation. The second part of the thesis describes design of the realization of the laboratory product. A microcontroller is used for data processing. There are discussed the possibilities of functions and the periphery control of connectable to microcontroller.
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Current sensing with Hall-effect sensors
Štindl, Daniel ; Kovář, Jan (referee) ; Šotner, Roman (advisor)
This master's thesis deals with integrated Hall-effect current sensors. The thesis contains summary of manufacturers of current sensors suitable for low current measurement and comparison of their important parameters. Next objective of the thesis is a design of test board used for evaluation of temperature depedent accuracy of several sensors simultaneously. The device can be connected with PC through USB interface for saving measured values or automated control with other instruments.
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Serial and Parallel Diagnostics of Vehicle Engine Control Units
Čoček, Jan ; Svída, David (referee) ; Beran, Martin (advisor)
The thesis considers diagnosis of motor vehicles from the past until the present day, focusing especially on the engine of internal combustion engines. In its sections briefly describes the function of the system and then analyzed how to diagnose faults. The charts are presented symptoms and denouement, using measuring techniques. The conclusion describes the OBD systems, the most commonly used automotive bus and a summary of several major measuring devices used in automotive diagnostics.
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