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Design of low-voltage supply and reference block based on the bandgap reference
Mudroch, Michal ; Kledrowetz, Vilém (referee) ; Prokop, Roman (advisor)
In this diploma thesis there is elaborated design of low-voltage power supply block using I3T25 technology. The theoretical part describes the basic structures used in the design, using CMOS and bipolar devices. Furthermore, the properties and the analysis used in the evaluation are described. In the design part there is an elaborated design of individual parts, including voltage references, current references, DAC converter, operational amplifier. In the last part, the power supply block is subjected to simulations for verification of temperature compensated output variables and analyzed circuit functionality.
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Mechanical and Electrical Properties of Thin Metal Films Deposited by Vacuum Evaporation
W. F. Yahya, Doaa ; Kolařík, Vladimír (referee) ; Štencl,, Jiří (referee) ; Šandera, Josef (advisor)
Thin layers are widely used in many fields of technology and today we can say that they are found in all modern technologies. Thin layers can be created in two ways, namely by chemical or physical means. This work focuses on the latter method, more particularly a technology of thermal evaporation of thin layers in a vacuum. The work focuses on the process principles during and after the evaporation. Much of the work focuses on the development and design of experiments. These experiments illustrate some of the phenomena that take place on thin films produced by the aforementioned technology. Work helps to better understand processes during formation of thin layers and properties that influence the quality and stability of thin films. In conclusion we describe results of experiments and new developments in the field of thin films deposition using evaporation under vakuum are summarized.
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Optimization of the Production of Lipases by Bacillus subtilis
Slavíčková, Radka ; Omelková, Jiřina (referee) ; Hermanová, Soňa (advisor)
In this thesis, optimization of production of lipolytic enzymes by submerzed cultivation of Bacillus subtilis (BS) was studied. Production of lipolytic enzymes was tested in three nutrient media, which differed mainly in main sources of carbon, respectively of nitrogen. The first medium contained mainly extract from calf brain and beef heart (BHIB), the second medium contained peptone and yeast extract (NB) and the third one contained peptone and yeast extract with the addition of 2% (w/v) glucose (NBG). The highest lipolytic activity (0.0784 Uml-1) was measured in NBG medium. Maximum of lipolytic activity was observed before the end of the exponential phase of BS growth in all the media. Temperature optimum in NBG medium was determined from 30 to 50 °C, pH optimum in the range of 5 to 11 and subsequently the temperature stability of lipolytic enzymes produced by the BS was estimated. The activity value was determined spectrometrically using p-nitrophenyllaurate as a substrate. Produced lipolytic enzymes showed maximum activity at 37 °C in the alkaline pH of 8.0. Measurement of temperature stability showed that lipolytic enzymes are relatively thermostable enzymes retaining 100 % of the activity even after 1 hour of cultivation at 30 - 50 °C. The presence of 1% (w/v) olive oil in medium NBG caused a decrease in lipolytic activity by 65 % as well as in pH from 6.5 to 5.4 after 14 days of cultivation. After substitution of glucose by fructose in medium NBG, lipolytic activity showed comparable values during the first week of cultivation. On the other hand, the decrease of lipolytic activity by 29 % in the medium with fructose was observed after 14 days of cultivation. A procedure for the identification of lipolytic enzymes of BS by peptide massfingerprinting was developed to understand the potential of synthetic polyester - poly(e-caprolactone) as a lipase inductor. Degradation study of commercial polyester poly(e-caprolactone) was carried out by submerged cultivation of Bacillus subtilis in NBG medium at initial pH 7.0 and 30 °C for 14 days. PCL (Mn = 10,000, Mw = 14 000) was studied in the form of films (1.0 x 1.0 cm), which were prepared by melt-pressing, rapid cooling of the melt to 4 °C and evaporation of the solvent from 2 % dichlormethane solution. The evaluation of the films shown occurrence of weight loss (7.8 - 17.0 wt.%) together with the formation of numerous holes and cracks in the sample surface in relation to the method of the films preparation. Lipolytic activity values increased by 9 - 17 % in the degradation media compared to control samples. Densitometric monitoring showed also higher increase in cell mass in the degradation medium compared with control samples. Based on the results obtained, the degradation process induced by BS could be suggested.
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Design of voltage references in BiCMOS ONC18 process
Dušek, Samuel ; Prokop, Roman (referee) ; Šotner, Roman (advisor)
This bachelor's thesis deals with design of voltage references in 180 nm technology of the ON Semiconductor company with main focus on the lowest value of power supply. First part presents theoretical knowledge concerning voltage references. The next part introduces chosen topologies, describes their function and methods of initial design. In this part there are also shown results which were achieved after initial design and after optimization of all references. The last part appraises the best replacement for bandgap etalon in area of power supply, where bandgap reference can not work properly.
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Design of low-voltage supply and reference block based on the bandgap reference
Mudroch, Michal ; Kledrowetz, Vilém (referee) ; Prokop, Roman (advisor)
In this diploma thesis there is elaborated design of low-voltage power supply block using I3T25 technology. The theoretical part describes the basic structures used in the design, using CMOS and bipolar devices. Furthermore, the properties and the analysis used in the evaluation are described. In the design part there is an elaborated design of individual parts, including voltage references, current references, DAC converter, operational amplifier. In the last part, the power supply block is subjected to simulations for verification of temperature compensated output variables and analyzed circuit functionality.
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Design of voltage references in BiCMOS ONC18 process
Dušek, Samuel ; Prokop, Roman (referee) ; Šotner, Roman (advisor)
This bachelor's thesis deals with design of voltage references in 180 nm technology of the ON Semiconductor company with main focus on the lowest value of power supply. First part presents theoretical knowledge concerning voltage references. The next part introduces chosen topologies, describes their function and methods of initial design. In this part there are also shown results which were achieved after initial design and after optimization of all references. The last part appraises the best replacement for bandgap etalon in area of power supply, where bandgap reference can not work properly.
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Mechanical and Electrical Properties of Thin Metal Films Deposited by Vacuum Evaporation
W. F. Yahya, Doaa ; Kolařík, Vladimír (referee) ; Štencl,, Jiří (referee) ; Šandera, Josef (advisor)
Thin layers are widely used in many fields of technology and today we can say that they are found in all modern technologies. Thin layers can be created in two ways, namely by chemical or physical means. This work focuses on the latter method, more particularly a technology of thermal evaporation of thin layers in a vacuum. The work focuses on the process principles during and after the evaporation. Much of the work focuses on the development and design of experiments. These experiments illustrate some of the phenomena that take place on thin films produced by the aforementioned technology. Work helps to better understand processes during formation of thin layers and properties that influence the quality and stability of thin films. In conclusion we describe results of experiments and new developments in the field of thin films deposition using evaporation under vakuum are summarized.
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|
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Optimization of the Production of Lipases by Bacillus subtilis
Slavíčková, Radka ; Omelková, Jiřina (referee) ; Hermanová, Soňa (advisor)
In this thesis, optimization of production of lipolytic enzymes by submerzed cultivation of Bacillus subtilis (BS) was studied. Production of lipolytic enzymes was tested in three nutrient media, which differed mainly in main sources of carbon, respectively of nitrogen. The first medium contained mainly extract from calf brain and beef heart (BHIB), the second medium contained peptone and yeast extract (NB) and the third one contained peptone and yeast extract with the addition of 2% (w/v) glucose (NBG). The highest lipolytic activity (0.0784 Uml-1) was measured in NBG medium. Maximum of lipolytic activity was observed before the end of the exponential phase of BS growth in all the media. Temperature optimum in NBG medium was determined from 30 to 50 °C, pH optimum in the range of 5 to 11 and subsequently the temperature stability of lipolytic enzymes produced by the BS was estimated. The activity value was determined spectrometrically using p-nitrophenyllaurate as a substrate. Produced lipolytic enzymes showed maximum activity at 37 °C in the alkaline pH of 8.0. Measurement of temperature stability showed that lipolytic enzymes are relatively thermostable enzymes retaining 100 % of the activity even after 1 hour of cultivation at 30 - 50 °C. The presence of 1% (w/v) olive oil in medium NBG caused a decrease in lipolytic activity by 65 % as well as in pH from 6.5 to 5.4 after 14 days of cultivation. After substitution of glucose by fructose in medium NBG, lipolytic activity showed comparable values during the first week of cultivation. On the other hand, the decrease of lipolytic activity by 29 % in the medium with fructose was observed after 14 days of cultivation. A procedure for the identification of lipolytic enzymes of BS by peptide massfingerprinting was developed to understand the potential of synthetic polyester - poly(e-caprolactone) as a lipase inductor. Degradation study of commercial polyester poly(e-caprolactone) was carried out by submerged cultivation of Bacillus subtilis in NBG medium at initial pH 7.0 and 30 °C for 14 days. PCL (Mn = 10,000, Mw = 14 000) was studied in the form of films (1.0 x 1.0 cm), which were prepared by melt-pressing, rapid cooling of the melt to 4 °C and evaporation of the solvent from 2 % dichlormethane solution. The evaluation of the films shown occurrence of weight loss (7.8 - 17.0 wt.%) together with the formation of numerous holes and cracks in the sample surface in relation to the method of the films preparation. Lipolytic activity values increased by 9 - 17 % in the degradation media compared to control samples. Densitometric monitoring showed also higher increase in cell mass in the degradation medium compared with control samples. Based on the results obtained, the degradation process induced by BS could be suggested.
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