National Repository of Grey Literature 201 records found  beginprevious191 - 200next  jump to record: Search took 0.01 seconds. 
Gas sensors, their construction and testing
Pytlíček, Zdeněk ; Boušek, Jaroslav (referee) ; Prášek, Jan (advisor)
This work deals with branch of gas sensors, their construction and methodology of testing. The general aim is a design and implementation of a station for simple testing of conduction gas sensors. The whole station is conceived as virtual measuring apparatus, operated by PC in LabView environment. The station enables mixing of any two gases at concentration demanded and measuring of the basic conduction characteristics of the thick-film and thin-film gas sensors. The central communication interface and modular conception enable easy expansion of possibilities of the whole apparatus in the future. It is possible to measure up to eight gas sensors split into two TO-12 packages simultaneously.
Study of organic based structures for solar cells
Kostovčík, Tomas ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
Práce se zabývá problematikou využití organických materiálů v solárních článcích. V úvodu práce jsou rozebrány a vysvětleny jednotlivé fyzikální a chemické jevy, které ovlivňují vlastnosti organických materiálů. Práce pokračuje rozborem působení rozličných struktur organických solárních článků na jejich vlastnosti. Dále je popsána technologie výroby vzorku a jsou v ní uvedeny výsledky měření fotovodivosti.
Worpllace for dynamic testring of solar cells.
Hanák, Kamil ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This work deals with method for characterization of photovoltaic solar cells based on evaluation of solar cell response to fast transients. The voltage of the cell in both forward and reverse polarisation was controlled by current pulse exciting. Real reverse breakdown voltage and exact value of serial resistance of the cell can be obtained easily by evaluation of the transient curves recorded by digital osciloscope. By negotiation of the time constants of the cell response to excitation in forward polarisation the lifetime of minority carriers in semiconductor bulk can be estimated.
Chemical passivation of surface for silicon solar cells
Solčanský, Marek ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This master´s thesis deals with an examination of different solution types a for the chemical passivation of a silicon surface. Various solutions are tested on silicon wafers for their consequent comparison. The main purpose of this work is to find optimal solution, which suits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibility of a perfect cleaning of a passivating solution remainig from a silicon surface, so that the parameters of a measured silicon wafer will not worsen and there will not be any contamination of the other wafers series in the production after a repetitive return of the measured wafer into the production process. The cleaning process itself is also a subject of a development.
Lifetime measurement of current carriers in silicon solar cells structures
Macháček, Martin ; Hégr, Ondřej (referee) ; Boušek, Jaroslav (advisor)
This thesis deals with a lifetime measurement of current carriers in silicon solar cell structures. In the first chapter there is a description of several recombination models and their participation at a final effective lifetime value. By using these recombination models in a computer simulation it is possible to receive approximate evaluation of some important silicon solar cell structure parameters. The PC1D simulation program was used for this thesis. For the lifetime measurement of real test-wafers two methods were used: QSSPC (quasi-steady-state photoconductance) and MW-PCD (microwave photoconductance decay). There is a detail description of these methods, used measurements machines and differences between both of them in the chapter four. The main objective of the thesis is mentioned in the last chapter, which is mainly focused on a chemical passivation of silicon wafers and deals with a problem of post-passivation wafer cleaning. There are three passivation techniques mentioned: the iodine in ethanol solution, the iodine and polymer in ethanol solution and the quinhydron in methanol solution. In two cases a results, that are adequate to return the tested wafers in the manufacture process, were achieved.
Remote Operated Probe for Deep-water Cave Exploration
Široký, Daniel ; Boušek, Jaroslav (referee) ; Šteffan, Pavel (advisor)
Předkládaná práce se zabývá návrhem a konstrukcí dálkově řízené sondy pro průzkum zatopených krasových oblastí. Cílem práce je zhotovení cenově přijatelné sondy pro speleologický výzkum. Soustava senzorů a dálkově řízený kamerový systém umožňuje pořízení záběrů z velkých hloubek, které lze později analyzovat.
Differential amplifiers with bipolar and field-effect transistors
Mašlan, Stanislav ; Boušek, Jaroslav (referee) ; Horák, Michal (advisor)
Simulation and comparison of various types of differential amplifiers.
Automated measurement system for gas sensors analysing
Stříteský, Stanislav ; Boušek, Jaroslav (referee) ; Přikryl, Radek (advisor)
Aim of this bachelor thesis was to propose and to realise the system of automatic control of appliance for measurement of hydrogen sensors characteristics and to verify the utility of the system on reference sample. The Appliance was built at FCH VUT in Brno. The program “sensor-tester” for controlling parts of appliance was made within this bachelor thesis. Moreover, reference samples of dipyridyldiketopyrrolopyrrole (DPPP) were analysed, controlling functionality of the program and sensors.
Sputtered coatings of SiNx:H on H2 plasma etched mono-Si substrate
Hégr, O. ; Boušek, J. ; Fořt, Tomáš ; Sobota, Jaroslav ; Vavruňková, V. ; Bařinka, R. ; Poruba, A.
The paper deals with cleaning, activation and ability of hydrogenation of monocrystalline silicon surface with the help of plasma etching in H2. Using the input gases Ar/H2 it is possible to initiate silicon surface chemical reactions acting similar to a standard chemical etching. The process is combined with deposition of SiNx:H layers on plasma etched substrate.
Characterization of multicrystalline solar cells with LBIC method in different wavelength
Fořt, Tomáš ; Jandová, K. ; Vaněk, J. ; Boušek, J.
For the determination of defects in the solar cells was used a method LBIC (Light Beam Induced Current). We use LED light source with various wavelengths to reveal the different types of defects. Using multiple wavelengths enables detecting defects in different depths. Surface defects can be observed in shorter wavelengths (400nm and 470nm). The junction region is well observed at wavelengths close to 525nm. Defects in the base material are visible using the light at a wavelength of 630nm or 890nm.

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1 Boušek, Jaroslav
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