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Electrical characterization of flexible nanofiber piezoelectric materials
Pokorná, Romana ; Holcman, Vladimír (referee) ; Tofel, Pavel (advisor)
This bacherol thesis is focused on piezoelectric nanofibrous materials. The first part describes the formation, use and possible aplications of nanofibers. It further analyze the principle of piezoelectric effect. It is a conversion of mechanical energy into electric energy and conversely. The second part is focused on design of experimental workplace for measurement of functional material properties. The last section of the thesis is dedicated to the electrical characterization of PVDF nanofibers and to the measurement of the piezoelectric charge constant.
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Semiconductor nanowire growth modelling
Kovács, Roland ; Bartošík, Miroslav (referee) ; Kolíbal, Miroslav (advisor)
This bachelor’s thesis deals with modelling of semiconductor nanowires growth. The work describes the mechanism of growth using the VLS method. The main objective is to simulate the distribution of eutectic material in a droplet in the initial stage of growth. Mathematical models describing different situations of material diffusion in the droplet were depeloped. The simulation model is programmed in MATLAB.
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Preparation and application of PHA based nanofibres and nanoparticles
Linha, Vojtěch ; Skoumalová, Petra (referee) ; Márová, Ivana (advisor)
The goal of this thesis was to summarize basic options of fiber spinning and manufacturing and their usability in industry. Methods of nanofiber spinning are described in the teoretical part, alongside the materials used in experimental part. The experimental part was focused on creating of workflow of defined nanofibers in laboratory enviroment, the possible modification of nanofibers with aditives. The release of aditives from different nanofibers into different enviroments was measured.
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Controlling of Nanostructure Temperature by Light Absorption
Kovács, Roland ; Schmidt,, Eduard (referee) ; Kalousek, Radek (advisor)
The thesis deals with a new versatile strategy which is aimed to heat up rapidly the nanostructures with the help of a focused light beam utilizing localized plasmons (collective oscillation of electrons). By local heating, the growth of the semiconductor nanowires can be initiated and controlled at any arbitrarily prespecified location down to the single nanostructure level in a chamber at room-temperature. The aim of the work is to study electromagnetic field in the selected structures, especially in metal nanospheres by using numeric calculations and computations of the thermal field in the vicinity of these illuminated nanostructures. Electromagnetic phenomena is simulated in Lumerical and the temperature field in COMSOL.
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Effect of pH on quantitative determination of additives in nanofibers
Grufíková, Jana ; Marek, Pokorný (referee) ; Knotková,, Kateřina (advisor)
The object of my thesis was to prepare a nanofiber layer with dye additives and to quantify the additive content in dependence on pH. The nanofiber layers with additives were prepared by means of electrospinning. The analysis of the additive content in samples was performed by UV-VIS spectrophotometry. Concretely Erythrosine, Eriochrome Black, Riboflavin and Brilliant Blue were analysed. Each of this colors has different chemical structure and charge. The pH was defined by use of buffers, namely acetate buffer (pH 5), phosphate buffer (pH 7,4) and carbonate buffer (pH 10). For Erythrosine and Eriochrome Black the research was extended to study the effect of ionic strength on the quantitative determination of these dyes. It was found that the quantity of the determined additive depends on the pH and also on the ionic strength. However, this dependency is different for each additive. This confirms the assumption of influenced chemical structure and charge by interaction with polymers and buffers used in this experiment. The accuracy of evaluation is influenced by the way of data processing.
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Castables with Inorganic Nanofibers
Zogata, Stanislav ; Keršnerová,, Lucie (referee) ; Sokolář, Radomír (advisor)
This work deals with the use of inorganic nanofibers in refractory castables. The thesis describes some of the results of previously conducted research on nanofibers. Also description of nanofibres, production and distribution. The experimental part is focused on studying the interaction of Al2O3 and SiO2 nanofibres with aluminate cement. The main subject of investigation is a dispersion of nanofibers using a surfactant and ultrasonication.
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Modification of semiconductor nanowire growth
Pejchal, Tomáš ; Grym, Jan (referee) ; Kolíbal, Miroslav (advisor)
This diploma thesis deals with the growth of semiconductor nanowires on Ge(111) surface. The nanowires were prepared by means of PVD (physical vapor deposition). The growth was calatyzed by Au colloidal nanoparticles. An impact of different growth conditions on nanowire morfology is presented. It is demonstrated that Ge nanowires grow preferentially along axis. Ge wires with orientation were observed as well.
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Theoretical use of nanotechnology for filtration in HVAC systems
Bosák, Jan ; Ell, Jiří (referee) ; Rubina, Aleš (advisor)
Thesis solves problems using the nanotechnology for air filtration in HVAC systems. Main specialization work is air filtration for clean spaces with high classes of purity. For example Hospitals, sophisticated technology service, pharmacy etc. Thesis is devide for three parts. First part contains foundation infromations about theory and making fabrics by nanotechnology. Next I described laws of physics, That were using during the solving filtration´s issues. Goal for second part was making the experiments, which should show abilities and properties nanofilters during the air filtration in real environment HVAC systems. In the end measure part is compare nanofilters with common filters. There is describe nanofiltres behavior and their possibilies during the filtration as well as. In last part I expressed own opinions on air filtration by nanofibers. Opinions were making throught informations, That I found out in the process working on thesis and my experiences in HVAC field. By this facts I did compare for get a better idea. Additionally last part contains summary infomations from previously parts and own vision to development in the future. Goal work isn´t promotion and advertising sorts technologies. Ask is just summary and describe discovered knowledges, considered opinions ensue from measuring, information from the Net and people Who work in nanotechnology field.
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