Papers

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2020-11-18
15:34

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2020-11-11
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2020-11-11
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2020-11-11
11:55

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2020-09-24
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2020-09-24
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2020-07-11
10:41
Chalcopyrite Solar Cells
Škvarenina, Ľubomír
Thin-film chalcopyrite based Cu(In;Ga)Se2 solar cells with a metal wrap through interconnection were investigated by non-destructive methods in our research. The primary focus of this investigation was a detection and a localization of microstructural defects in this type of Cu(In;Ga)Se2 solar cells. A combination of a visible and near infrared electroluminescence with a lock-in thermography was used for these purposes. Mainly the electroluminescence was a very sensitive tool for an indication of pre-breakdown sites influenced by a trap-assisted tunneling or stress-induced leakage currents. A strong correlation between electroluminescence maps and lock-in thermograms was obtained after a local breakdown accompanied by a creation of permanent defect.

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2020-07-11
10:41
Lead-Acid Battery Evaluation Based On Opencircuit Voltage Fluctuation Measurement
Kuparowitz, Tomáš ; Kuparowitz, Martin
The state of charge and the state of health are two crucial parameters of batteries. Current state of the art methods of their estimation include some as simple as measuring open circuit voltage, all the way to fuzzy logic estimation and constant online battery overview. Some main problems of such methods are either the length of single parameter evaluation cycle, or their inherent inaccuracy due to limitations in battery manufacture precision. This article proposes novel method of the lead-acid battery state of the health estimation, based on open circuit noise measurement. It reports the nature of changes in low frequency noise spectral density, that occur after catastrophic self-discharge failure or avalanche voltage drop in lead-acid batteries.

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2020-07-11
10:41
Characteristics Of Gallium Arsenide Solar Cellsat High Temperature
Papež, Nikola
This article reviews a work on processing of gallium arsenide (GaAs) solar cells. The performance of the cells before and after 300 _x000E_C thermal processing was correlated with topography identified by optical camera, atomic force microscope (AFM) and scanning electron microscope (SEM). Experiment indicates insignificant changes in topography of GaAs solar cells, but electrical characteristics show an excellent resistance of the samples to processing temperature.

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2020-07-11
10:41
Neural Network For Testing
Smetana, Bedřich
This article describes basics of neural networks, specifically aimed at usage of freeware to test freeware for creation simple neural network. Discussion focuses on the use of generally available programs and problems with use of freeware applications. Attention is devoted to a comparison of real and theoretical conditions connected with practical computer support.

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