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High Temperature Processes in Silicon Solar Cells Production
Frantík, Ondřej ; Hudec, Lubomír (referee) ; Banský,, Juraj (referee) ; Szendiuch, Ivan (advisor)
The thesis is focused on high temperature processes in crystalline solar cells production. Main topic is diffusion of traditional dopants phosphorus and boron. Diffusion processes for creating solar cells are different from classical diffusion in semiconductor industrial. It is reason why the thesis describes crated layers in detail. Knowledge of diffusion processes is used for creating bifacial solar cells and development of a new phosphorus emitter for conventional solar cells. Bifacial cells are a new type of cells. Developed new emitter increases efficiency and decreases cost of solar cells production. Another part the thesis is devoted to the prediction of diffusion processes. New models of phosphorus and boron diffusion for photovoltaic industrial are created in software SILVACO. Models correspond with real results.
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Fluoride coatings on magnesium prepared in melts
Drábiková, Juliána ; Richtera, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This work deals with the corrosion protection of magnesium alloy AZ31, AZ61, AZ91 using fluoride conversion coating prepared from Na[BF4] melt. The theoretical part describes the properties of magnesium alloys, the recent results of fluoride conversion coatings preparation and analysis of the available literature about the properties of salt Na[BF4] and its decomposition products. The experimental part was devided into two main sections. The first deals with the corrosion resistance of the treated magnesium alloys (AZ31, AZ61, AZ91 and AZ91 annealed) in the Na[BF4] melt. Corrosion resistance was tested using potentiodynamic tests and tests in the corrosion chamber. In the second part, the mechanism has been studied for preparing fluoride conversion coating, where it was shown that in air-free atmosphere the oxidizing agent in the process is boron, which is reduced from BIII to B0, and thereby enables the fluoride conversion coating.
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Issues of boron in water
Šípková, Helena ; Nevrlá, Jana (referee) ; Komendová, Renata (advisor)
This bachelor thesis is focused on boron and its compounds. It is dedicated to properties, sources and the use of these substances and their effects on living organisms. The emphasis is put on the issue of boron in water. In this work are possible forms of this element in water, legislative rules and regulations and methods of its determination described. The experimental part is focused on azomethine-H spectrophotometric analysis to identify the stability of boron samples and their possible preservation.
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Mimokořenová výživa B, Zn a Mo u kořenové zeleniny
Očenášková, Květa
There are many external and internal factors which influence the quality and yields of vegetables. Counted among the external factors is nutrition and fertilisation which are an integral part of growing technologies. Without sufficient and balanced supply of acceptable nutrients the plants are not capable of achieving high quality and yields. Among the essential nutrients we also count micro biogenic elements. Although vegetables require only small amounts, their importance is equal to nitrogen, phosphorus, potassium and other macro elements. The first part of the bachelor dissertation thesis maps the present information about the importance of some micro nutrients (B, Zn, Mo) in the nutrition of vegetables. In a two-year vegetation experiment we explored the effect of foliar applications of some micro elements on their content in radish plants and on the yields of the edible part of this root vegetable. The experiment was established as a pot experiment in soil culture. During vegetation we applied the nutrients at graded rates. The effect of the foliar application was evaluated on the basis of analyses of the plant mass and yield parameters. The results showed that foliar nutrition with micro nutrients increased their contents namely in the leaves, but also in the radish roots. Fertilisation had a significant effect on the yields of whole plants in a similar way as on the edible roots. Supplementary fertilisation with the micro nutrients increased roots yields by 7,0 to 46%. Zinc at a rate equal to an application of 700 g Zn.ha-1 had a statistically significant effect on the production of radish roots. Radish yields increased significantly also after the application of molybdenum at a rate equal to 62.5 g Mo.ha-1.
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