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General overview of GaN devices and transport properties of AlGaN/GaN HEMT structures - impact of dislocation density and improved design
Hulicius, Eduard ; Hájek, František ; Hospodková, Alice ; Hubík, Pavel ; Gedeonová, Zuzana ; Hubáček, Tomáš ; Pangrác, Jiří ; Kuldová, Karla
GaN-based nanostructures are used for many present semiconductor devices. The main topics are structures for blue LEDs and LDs, but there are also other interesting and important GaN devices namely for power electronics, scintillators and detectors as well as High Electron Mobility Transistors (HEMT). Reduction of dislocation density considerably increases electron mobility in 2DEG. All presented results support our expectation that a suitably designed AlGaN back barrier can help to prevent this phenomenon.
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Compost accelerator to composters and garden composts
HÁJEK, František
The purpose of this paper is to research and suggest good-quality compost accelerators that could be effectively used in the garden composts. The additive eliminates the shortage of the input pulverized grass matter which is being composted. This thesis also describes the features of the compost, the nature of the correct composting procedures, and the legal implications to the production of the composting process. This paper elaborates the efficiency of the compost accelerators that are available within the home market and abroad. An important component of my accelerator is magnesium from the Dolomites limestone distributed by the "HASIT" company which positively affects the process of humification. The experiment of compostation with this type of accelerator took place on the pulverized grass matter. In order to objectively assess the quality of the composts, the Sanhoff´s method of stating the cation exchange capacity was used. During this experiment, the cation exchange capacity increased by 22% in the sample where the accelerator has been used, as compared to the sample where only the composted grass matter was present. Based on the results gathered, it is feasible to conclude that the suggested accelerator does have a significant impact on the composting of the grass matter. Due to this fact, it is strongly recommended to conduct a further research on the composition of the compost accelerators.
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