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Pulsed plasma systems
Klusoň, Jan ; Kudrna, Pavel (advisor) ; Krčma, František (referee) ; Čada, Martin (referee)
The doctoral thesis deals with the experimental study of the low-temperature plasma designated for the preparation of thin films using the method of physical sputtering. It describes measurements which were realized on two types of devices - on the low-pressure plasma jet sputtering system and on the planar magnetron. The plasma diagnostics in the discharge excited in the pulse regime represent the main theme of the thesis. The discharge in the low-pressure plasma jet was studied by means of an electrostatic Langmuir probe, in the case of the planar magnetron, mass spectroscopy with energetic as well as time resolution was used. To understand the results achieved in the pulse generated plasma good knowledge of the basic continuous DC regime of the discharge excitation is essential. Therefore a considerable part of the thesis deals purely with the continuous DC discharge. In the case of the low- pressure plasma jet, the attention was focused also on the characteristic property of this plasma source, which is the flow from the jet.
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Studium parametrů plazmatu v plazmatické trysce
Štefániková, Estera ; Tichý, Milan (advisor) ; Klusoň, Jan (referee)
This thesis deals with the low-temperature plasma diagnostics by means of electrostatic Langmuir probe. The measurements were carried out on the experimental system of plasma jet which is very perspective mainly for the deposition of thin layers. Besides different resistant and industrial compelling surfaces there are also some layers with specific electrical or optical properties that cannot be prepared in other way. In order to control and reproduce such material depositions, the knowledge of plasma parameters is inevitable. The main contribution of this work lies in the measurement of vertical profiles of main plasma parameters (electron temperature, density and mean energy; the floating and plasma potential) in different pressure conditions.
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Technology of Production Frame of Case
Tvarůžek, Martin ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
The bachelor Thesis compares and evaluates the most advanced production technology of components frame of case. These cases are used for induction heating of material. The thesis compares technological features of the material division by means of plasma jet, water jet and laser. It also evaluates the using of the given technology from economic point of view.
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Volumetric Velocimetry and Accelerometry of Injected Particles in Thermal Plasma Jet
Šonský, Jiří
Measurements of the injected particles velocities and accelerations in the plasma jet are important for thermal plasma spraying technology improvement. Commonly used methods of optical diagnostic, such as particle image velocimetry (PIV) or particle tracking velocimetry and accelerometry (PTVA),are complicated due to strong optical self-emission of the plasma jet. We have developed 3-D variant of the PTVA, able to measure particle velocities and accelerations in hot core of the thermal plasma jet, as well as in surrouding areas, such as entrance of particle flow into the plasma jet.
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Numerical simulations of jet formation in laser-target interactions
Váchal, P. ; Liska, R. ; Kuchařík, M. ; Limpouch, J. ; Kmetík, Viliam
Cylindrical version of our two-dimensional Arbitrary Lagrangian Eulerian code PALE is applied for numerical studies of dense plasma jet formation from laser targets. Well collimated plasma expansion from a massive solid target irradiated by a single laser beam with a special profile is investigated. Particular interaction beam profile with intensity minimum in the beam centre is found to be responsible for jet formation during plasma expansion. A deep concave interaction beam profile at PALS is obtained from our simulation of the laser propagation in the amplifying chain and in the focusing system.
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Depozice tenkých vrstev Ba.sub.x./sub.Sr.sub.1-x./sub.TiO.sub.3./sub. pomocí dvoutryskového RF plazmatického systému s efektem duté katody
Hubička, Zdeněk ; Virostko, Petr ; Olejníček, Jiří ; Deyneka, Alexander ; Adámek, Petr ; Valvoda, V. ; Jastrabík, Lubomír ; Šícha, Miloš ; Tichý, M.
Low-pressure plasma jet system with two hollow cathodes was used for deposition of BaxSr1-xTiO3 (BSTO) ferroelectric thin films. High density pulse modulated RF hollow cathode discharge was generated in ceramic nozzles made of SrTiO3 and BaTiO3. In the experiment, the composition of BSTO films was controlled by magnitude of average RF power applied on particular plasma jet guns. X-ray diffraction proved that BSTO thin films were polycrystalline with perovskite structure. Time resolved Langmuir probe system and plasma impedance monitor were used for ´in situ´ plasma diagnostics and control of deposition conditions.
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Vliv připojeni oblouku k anodě na proud termického plazmatu
Chumak, Oleksiy ; Kavka, Tetyana ; Hrabovský, Milan
The paper examines an effect of an argon amount on the thermal plasma jet generated from water/argon mixture in a dc arc plasma torch. In spite of an increase of plasma velocity with an addition of argon a decrease of plasma jet length is observed for bigger argon amount in the plasma. The investigation was based on an analysis of a jet structure based on imaging of the plasma jet by a CCD camera. Statistical processing of plasma jet photographs provided information about a jet shape and its fluctuations space distribution. It was found that an argon amount increase caused significant intensification of the plasma jet fluctuations.
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Měření excitačních a ionizačních teplot v expandujícím proudu H2O-Ar plazmatu
Sember, Viktor ; Mašláni, Alan
Optical emission spectroscopy is used to determine the temperature in a plasma jet expanding from the H2O-Ar dc arc torch into a chamber maintained at a pressure of 10 kPa. The excitation and rotational temperatures are derived from relative intensities of argon atomic and ionic lines, and from the UV OH band at 306.357 nm, respectively. The ionization temperature is obtained from the intensity ratio of argon ionic and atomic lines, using electron number density calculated from the Stark broadening of hydrogen H line. The structure of the plasma jet is characterized by isocontours of electron number density and intensity of atomic and ionic lines. In the expansion region, the ionic excitation temperature is found close to the ionization temperature and much higher than the excitation temperature of argon atoms, which is close to the rotational temperature of OH radical. In the normal shock region, all the measured temperatures tend to be equal.
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