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Radicals formation in supersonic plasma jet
Mašát, Milan ; Tichý, Milan (advisor) ; Glosík, Juraj (referee)
Title: Creation of radicals in electric discharge supersonic plasma jet Author: Milan MaSat Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Milan Tichy, DrSc. Supervisor's e-mail address: Milan.Tichy@mff.cuni.cz Abstract: Free radicals are the key intermediates and propagators of chemical reactions in Earth's atmosphere. Study of their structure and chemical properties is vital for understanding the processes in atmosphere. But their high reactivity brings the need for specific research methods. In-situ preparation and non-invasive detection and characterization techniques are needed. Most commonly used laboratory techniques such as photodissociation or electric discharge generate radicals at temperatures that are significantly higher then those under atmospheric conditions, which we intendto model. In this work, I was developing a source of cold radicals and experimental techniques for measuring their properties. 1 combined plasma source, which creates sufficient concentrations of radicals with supersonic expansion in which the translational and internal degrees of freedom are cooled deeply below the room temperature. For their characterization I used high-resolution spectroscopy utilizing near infrared laser diodes. I also developed and built electronic circuits and software...
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Ultrathin films deposited by means of magnetron sputtering and their characterization
Petr, Martin ; Kylián, Ondřej (advisor) ; Straňák, Vítězslav (referee) ; Tichý, Milan (referee)
Presented work is focused on the deposition and characterization of thin and ultrathin plasma polymer films, then also on the preparation of nanocomposites metal/plasma polymer. The characterization of plasma polymer films was partly done in-situ without exposing the samples to the atmosphere. The thickness of prepared films was measured by spectral ellipsometry, the chemical composition was measured by XPS. The morphology and optical properties of deposited films were measured ex-situ. It is shown that during the initial stages of growth the properties of plasma polymer films depend on their thickness and also on the material of the substrate. Many interesting applications were explored for prepared nanocomposites metal/plasma polymer. They can be used as superhydrophobic coatings, gradient coatings, substrates for Raman spectroscopy or as antibacterial coatings. Moreover, special optical properties of prepared nanocomposites were studied in detail. Presented work has an experimental character.
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Diagnostics of low-temperature plasma using the Langmuir and emissive probes
Klusoň, Jan ; Kudrna, Pavel (advisor) ; Tichý, Milan (referee)
Magnetron sputtering belongs to the most important methods of production of thin films with a wide range of physical properties. Examples include hard, wear-resistant coatings, low friction ones, corrosion resistant ones as well as coatings with specific electrical or optical properties. During the development the basic sputtering process has been significantly improved and nowadays there are a number of various techniques of magnetron sputtering. Pulsed magnetron sputtering presents one of these techniques. The pulsed regime is especially suitable for the deposition of insulating layers because there occurs no effect of charging up of the target followed by arc events. The fact that pulsed sputtering allows reducing the substrate temperature during the deposition is also important. This thesis deals with the low-temperature plasma in magnetron discharge generated by pulsed DC voltage. The measurement was carried out in the experimental apparatus of the cylindrical magnetron. The plasma diagnostics was performed by means of the electrostatic Langmuir and emissive probe. The dependencies of the basic plasma parameters, i.e. electron density, electron temperature and plasma potential, were evaluated with time and spatial resolution. The dependencies on pressure, length of the voltage pulse and the value of...
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Selected issues of thermonuclear fusion in tokamak-like magnetic containers
Ondáč, Peter ; Tichý, Milan (advisor) ; Kudrna, Pavel (referee)
In this thesis there are summarized in the form of basic knowledge the basic problems of fusion research. It serves as an introduction to this field of physics for beginners, but also intermediate candidates. The first two chapters set out the basic terms and ideas associated with controlled thermonuclear fusion. Further described is the magnetic confinement in tokamaks. Physically most important is the third chapter, which includes more advanced parts of physics. It discusses the main focus of this work, i.e. some of the major problems hindering fusion research. Final fourth chapter is relaxed. It discusses the ideas and visions for the near and distant future.
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Experimental and theoretical study of utilization of probe methods for plasma diagnostics
Peterka, Matěj ; Tichý, Milan (advisor) ; Horáček, Jan (referee)
The ball-pen probe is a unique probe recently developed at the Institite of Plasma Physics in Prague. It has been designed for direct measurement of plasma potential at the CASTOR tokamak. Nowadays, it is used routinely at several tokamaks in Europe, and the first tests in low-temperature plasma have also already been performed. The aims of the thesis are primarily experimental. A ball-pen probe has been constructed from available materials, which is suitable for systematic measurements of radial profiles in the low-temperature plasma of a cylindrical magnetron. By means of comparison to other diagnostics, it was proved that ball- pen probe is able to directly measure plasma potential in a certain range of plasma parameters even though its current-voltage characteristic is not symmetric, which is in contradiction with the simplified theory for ball-pen probe. Powered by TCPDF (www.tcpdf.org)
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Probe diagnostics of the pulse-generated plasma
Turek, Zdeněk ; Tichý, Milan (advisor) ; Kaňka, Adolf (referee)
The subject of the bachelor thesis is the plasma diagnostics in the planar magnetron and in the hollow cathode system operating in the pulse mode, when the plasma is generated by DC pulses. The diagnostics method used will be the Langmuir probe. The aim of the thesis is the construction of the computer-controlled electronic measuring system and its assessment when measuring the parameters of argon discharge plasma in both systems with time resolution i.e. depending on time during one pulse period.
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Study of instabilities in tokamak plasmas using radiation diagnostics
Imríšek, Martin ; Tichý, Milan (advisor) ; Igochine, Valentin (referee) ; Jardin, Axel (referee)
Title: Study of instabilities in tokamak plasmas using radiation diagnostics Author: Martin Imríšek Department: Department of Surface and Plasma Science Supervisor: Prof. RNDr. Milan Tichý, DrSc. Consultants: Mgr. Vladimír Weinzettl, PhD. RNDr. Jan Mlynář, PhD. Abstract: The thesis focuses on the characterisation of sawtooth instability and its effect on selected edge plasma processes at COMPASS. It is shown that saw- tooth crash precedes the vast majority of L-H transitions, lower occurrence of ELMs and transitions to ELM-free H-mode. The sawtooth instability also af- fects H-L transitions, as their increased occurrence is observed in the middle of the sawtooth cycle. In the thesis, optimised tomography of the electromagnetic emission at COMPASS and JET is also applied to study instabilities in tokamak plasmas. The performance of fast tomographic methods with potential for real- time plasma control purposes is also studied. As the magnetic field configuration plays a vital role in plasma stability and tomographic reconstructions, the thesis also includes simulations of magnetic fields. These simulations were applied to optimise the design of coils for COMPASS-U. Keywords: tokamak, tomography, sawtooth instability, electromagnetic emission iii
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Multicomponent plasma polymers with spatially controlled properties
Pleskunov, Pavel ; Shukurov, Andrey (advisor) ; Čech, Vladimír (referee) ; Tichý, Milan (referee)
Title: Multicomponent plasma polymers with spatially controlled properties Author: MSc. Pavel Pleskunov Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Prof. Ing. Andrey Shukurov, PhD, Department of Macromolecular Physics / Charles University Abstract: Mixing of two (or more) polymers often leads to phase separation and to the formation of nanoscale architecture, which can be highly attractive in various applications including controllable drug delivery, fabrication of separation and solid electrolyte membranes, gas storage, etc. Different wet-chemistry techniques already exist to produce nanophase-separated polymers; however, capturing the resultant polymeric structure in a predictable manner remains a challenging task. In this thesis, a low-temperature plasma-based strategy is investigated for the production of multicomponent thin films of plasma polymers with spatially discriminated nanoscale domains. Gas aggregation cluster source is used for the fabrication of nanoparticles of plasma polymerized acrylic acid, whereas Plasma-Assisted Vapor Phase Deposition is used for the deposition of thin films of poly(ethylene oxide) plasma polymer. Embedding of nanoparticles into matrices of thermodynamically incompatible plasma polymer as well as...
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