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Electromigration of defects in (CdZn)Te single crystals.
Pekárek, Jakub ; Belas, Eduard (advisor) ; Grill, Roman (referee)
In the present work we study effect of electromigration of defects in CdTe material in external electric field at various temperatures and biases. The aim was to verify this effect using a set of electric contacts arranged linearly along the sample. These contacts as a potential probes was used for the detection of the drift of the local resistance modulation. We try to determine under what conditions and why it happens and then decide how this effect can be used for purification of semi-conducting samples and for preparation of semi-insulating material.
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Electromigration of Flux Residues on PCB Surface
Tylich, Ondřej ; Zatloukal, Miroslav (referee) ; Starý, Jiří (advisor)
Diploma thesis introduces the problems of electromigration, fluxes and flux residues. It includes a proposal for methods of measuring surface insulation resistance, information about selected types of fluxes and conformal coatings. It focuses on the influence of temperature, humidity. There are applied conductometric method and method of measuring SIR by IPC-25-B. The thesis describes the practical measurement of SIR and ionic contamination of PCB covered with flux and influence of RH, temperature and applied voltage is evaluated and discussed.
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Wave Soldering Fluxes and Flux Residues
Kryll, Josef ; Dušek, Karel (referee) ; Starý, Jiří (advisor)
This work deals with issues of flux residues after wave Soldering. The general aim is to create methodology for measuring the surface insulation resistance values of flux residues after soldering and isothermal heating. Finding the ammount of ionic contamination by using conductometric method. Measurement of wettability of Cu wire by using wetting balance method for different fluxes. The aim is then to compare the measured values with the values dictated by the manufacturer.
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Flux Residues after Reflow Soldering
Uhlář, Vít ; Špinka, Jiří (referee) ; Starý, Jiří (advisor)
The aim of this bachelor thesis is to solve flux residue characteristics on PCBś after reflow soldering and compare different solder pastes. The first part deals with the issue of solder paste application and flux residues. The second part focuses on the process of reflow soldering. The third part is devoted to the measurement methodology of flux residues. Finally, project is a practical part, which is summarized in the production of test samples and contains measurement results.
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