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Analysis of high-speed induction motor
Klíma, Jiří ; Ondrůšek, Čestmír (referee) ; Vítek, Ondřej (advisor)
This thesis deals with the problem of the high-speed induction machines. In the introduction the design of the machines and problem areas are discussed. The feeding from the frequency converter and the mechanical strength of the rotor appear to be the biggest problem. High-speed engines with solid rotors were designed. The first model is equipped with a conductive cooper layer on the surface. This model is exposed to harmonic and non-harmonic input voltage and then the results of the simulations are compared. The following model of the thesis is equipped with axial slots. In the practical part of the thesis no load measurement is taken. One point was measured at nominal frequency. At the end of the thesis the results of the measurements are compared with the results of the figures extracted from Maxwell software.
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Search in field of core shooter machines
Klíma, Jiří ; Pavlík, Jan (referee) ; Bradáč, František (advisor)
This thesis deals with construction and technology of core shooter machines. Thesis contains basic characteristics of machines and overview of world manufacturers. The machines are compared in terms of arrangement and used equipment. For completeness, there is focus on single core production technology, preparation of raw materials and manufacturing automation. In conclusion there is assessment of the current situation and view on future developments in this area.
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Ultrathin nanofibrous membranes with enhanced properties for transplantation of retinal pigment epithelial cells
Studenovská, Hana ; Popelka, Štěpán ; Abelová, Lucie ; Riedel, Tomáš ; Studený, P. ; Straňák, Z. ; Klíma, Jiří ; Ardan, Taras ; Dvořánková, B. ; Rypáček, František
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FOX-7 - Study of Reduction Products of Spectroelectrochemical Methods
Šimková, Ludmila ; Dmitrieva, E. ; Klíma, Jiří ; Dunsch, L. ; Ludvík, Jiří
A new energetic material 2,2-dinitroethene-1,1-diamine (FOX-7) is recently broadly tested because of its high performance and very low sensitivity. On the other hand, its electrochemical and redox properties have not been studied yet. Our results show that FOX-7 is reduced in aprotic solvents only by two one-electron steps up to -2.9 V. The color changes during reduction of FOX-7 and reversibility of the redox process indicate the presence of radical intermediates. Therefore in situ UV-vis-NIR and ESR spectroelectrochemical investigations were performed. The products after exhaustive electrolyses were separated by HPLC and are identified by mass spectrometry. The possible formation of gaseous products was followed online EC-GC.
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Electrochemical and spectrometric study of FOX-7 in aprotic solvents
Šimková, Ludmila ; Ludvík, Jiří ; Klíma, Jiří
2,2-Dinitroethene-1,1-diamine (FOX-7) is a recently developed and broadly tested energetic material with high efficiency and low sensitivity. Generally, explosion is based on thermally initiated chain of intramolecular redox reactions. Recently it has been found that electrochemical reduction in aqueous solutions is also able to provoke the chain of follow-up processes leading to total decomposition of the parent substance yielding gaseous products analogously like during explosion. Similarly, results from reductive electrolysis of FOX-7 in aprotic solvents show analogous course of degradation. The first transferred electron activates the molecule and initiated the formation of colored radical intermediates that have been spectroscopically characterized
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Strange Redox Behavior of 1,1-Diamino-2,2-dinitroethene
Šimková, Ludmila ; Ludvík, Jiří ; Klíma, Jiří
The expected product of polarographic reduction of 1,1-diamino-2,2-dinitroethene (FOX-7) in aqueous buffered solutions is ethan-1,2-diamine. But exhaustive electrolysis did not show this product. The main products are gases. Due to combination of electrochemistry and GC and with MS analysis were found following gaseous products: N-2, NO, N2O, H2O. However, no carbon containing gaseous product was found. A part of products remains probably in the water solution as inorganic ions. The degradation process accompanying the exhaustive electrolysis seems to be analogous to the reactions during explosion, but under very low concentration, cooled and slowed down by the solvent.
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Charakterizace míšních progenitorových buněk in vitro
Vitásková, Martina ; Klíma, Jiří ; Vodička, Petr ; Motlík, Jan
We performed in vitro studies with the spinal cord of mice and miniature pig. Employing papain dissociation system we isolated neural progenitor cells and cultured them in DMEM/F12 HEPES, Ala-Glu, gentamicin, heparin, B27 supplement without vitamin A, N2 supplement, EGF (Epidermal Growth Factor) and bFGF (Basic Fibroblast Growth Factor). We added retinoic acid and 10% fetal bovine serum into cultivation media to induce cell differentiation. Using immunocytochemistry we confirmed cell capability to differentiate into neurons (βIII-tubulin, Map 2A - Microtubule Associated Protein), astroglia (GFAP – Glial Fibrillary Acidic Protein), and oligodendroglia (CNPase - 2',3'-cyclic nucleotide 3'-phosphodiesterase). Cells can keep non-differentiated status for a longer period of time when cultured in low adhesion culturing flask or by addition of LIF (Leukemia Inhibitory Factor) to the cultivation media.
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