No (399)
Yes (48)
Number of found documents:
447
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The role of pre-ionization on EUV capillary laser profile.
Štraus, Jaroslav; Schmidt, Jiří; Koláček, Karel; Frolov, Oleksandr
2017 - English
The profile of EUV capillary laser beam was believed to be an annulus and a corresponding theory for its explanation was generally accepted. Nevertheless, our recent detailed observation shows, that the laser profile can be remarkably influenced by the parameters of pre-pulse, serving for working gas pre-ionisation before introduction the main current into the capillary. The examples of possible profile shapes and corresponding parameters are presented.
Keywords:
Pre-pulse; capillary XUV laser beam profile
Available at various institutes of the ASCR
The role of pre-ionization on EUV capillary laser profile.
The profile of EUV capillary laser beam was believed to be an annulus and a corresponding theory for its explanation was generally accepted. Nevertheless, our recent detailed observation shows, that ...
Application of Electric Probes for Study of Structure of Thermal Plasma Jet.
Hurba, Oleksiy; Hrabovský, Milan
2017 - English
Thermal plasma at atmospheric pressure was investigated. Electric probes and doable probe used as relatively simple and efficient tool for diagnostic of structure of flow field in thermal plasma jet. Were defined plasma potential and boundaries of the conducting region and their changing for the diferent operating modes of plasma torch.
Keywords:
Electric probes; double probe; thermal; plasma jet
Available at various institutes of the ASCR
Application of Electric Probes for Study of Structure of Thermal Plasma Jet.
Thermal plasma at atmospheric pressure was investigated. Electric probes and doable probe used as relatively simple and efficient tool for diagnostic of structure of flow field in thermal plasma jet. ...
Material design problems of plasma-chemical reactors for disposal perfluorinated compounds
Brožek, Vlastimil; Březina, Václav; Mastný, L.; Kubatík, Tomáš František; Živný, Oldřich
2017 - English
Reduction of perfluorinated gases emissions from semiconductor industry has recently introduced a serious problem from both technological and economic side. With respect to chemistry of the decomposition reactions the most effective abatement techniques developed up to now consists in the interaction of those gaseous pollutants with several types of plasmas. In the framework of Czech-Taiwanese bilateral project No. 17-10246J 'Decomposition of Perfluorinated Compounds and Fluorinated Ozone Depleting Substances' a new plasmochemical reactor design is to be solved. In this reactor the plasma abatement process consisting of interaction of the plasma generated by unique watter stabilized H-WSP plasma torch at temperatures ranging\nfrom 2000 K up to 25,000 K with the treated gases will be carried out. However, the main product generated in the reactor during the steam plasma abatement process is hydrogen fluoride which causes corrosion of almost every construction material. The aim pursued by the work presented is to search for the materials resistant to exposition of HF even at high temperatures. To investigate corrosion resistance of construction materials with thermal stability within temperature interval 2700-3000 °C titan nitride, boron nitride, and silicon carbide have been selected. The samples of those materials have been prepared by spark plasma sintering method and exposed to concentrated solution of hydrofluoric acid for which corrosion rates have been measured
Keywords:
perfluorinated compounds; thermal plasma torch; boron nitride; titanium nitride; silicon carbide
Available at various institutes of the ASCR
Material design problems of plasma-chemical reactors for disposal perfluorinated compounds
Reduction of perfluorinated gases emissions from semiconductor industry has recently introduced a serious problem from both technological and economic side. With respect to chemistry of the ...
Properties of hydroxyapatite surface deposited by plasma spray technologies
Matějková, M.; Čížek, Jan; Mušálek, Radek; Dlouhý, I.
2017 - English
The surface properties of hydroxyapatite (HA) deposited on the Ti-6Al-4V substrates by plasma spraying were studied. Two different plasma spray technologies (hybrid plasma spray system (WSP-H) and conventional atmospheric plasma spray technology (APS)) and two various feedstock (suspension for WSP-H and powder for APS) were used for deposition of HA layers potentially suitable for bio-applications. The layers properties (thickness, chemical and phase composition) and coating-substrate interface quality were analyzed. The XRD analysis showed formation of small amount of new phases (TTCP and CaO) in layers deposited by WSP-H. Better coating-substrate interface quality of samples prepared by WSP-H was observed. The results showed the deposition of HA through liquid feedstock via WSP-H as a promising route, complementing the traditional APS powder deposition in the near future.
Keywords:
hydroxyapatite; hybrid water-stabilized plasma spray; atmospheric plasma spray technology
Fulltext is available at external website.
Properties of hydroxyapatite surface deposited by plasma spray technologies
The surface properties of hydroxyapatite (HA) deposited on the Ti-6Al-4V substrates by plasma spraying were studied. Two different plasma spray technologies (hybrid plasma spray system (WSP-H) and ...
ADHESION OF BIOCOMPATIBLE TiNb COATING
Kolegar, T.; Matoušek, M.; Vilémová, Monika; Starý, V.
2017 - English
Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several materials such as titanium CP grade 2, titanium alloys Ti6Al4V and stainless steel AISI 316L were measured. Testing samples were made in the shape of small discs. Those samples were coated with a TiNb layer by using the PVD method (magnetron sputtering). Onto the measured layer of TiNb an assistant cylinder was stuck using a high strength epoxy adhesive E1100S. The sample with the assistant cylinder was fixed into a special fixture and the whole assembly underwent pull-off testing for adhesion. The main result of this experiment was determining the strength needed to peel the layer and morphology and size of the breakaway. As a result, we will be able to determine the best base material and conditions where the coating will be remain intact with the base material.
Keywords:
PVD coating; Adhesion; Biocompatible materials; Pull-off test; Titanium; Niobium
Available at various institutes of the ASCR
ADHESION OF BIOCOMPATIBLE TiNb COATING
Preparation of a coating with a high quality requires good adhesion of the film to the substrate. The paper deals with the adhesion of biocompatible TiNb coating with different base materials. Several ...
RE beam generation in MGI disruptions on COMPASS.
Ficker, Ondřej; Mlynář, Jan; Macúšová, Eva; Vlainić, M.; Weinzettl, Vladimír; Urban, Jakub; Čeřovský, Jaroslav; Farník, Michal; Markovič, Tomáš; Papřok, Richard; Vondráček, Petr; Imríšek, Martin; Tomeš, Matěj; Havlíček, Josef; Varju, Jozef; Varavin, Mykyta; Bogár, Ondrej; Havránek, Aleš; Gospodarczyk, M.; Rabinski, M.; Jakubowski, M.; Malinovski, K.; Zebrowski, J.; Plyusnin, V.; Papp, G.; Pánek, Radomír; Hron, Martin
2017 - English
In the experiments with the massive gas injection (MGI) triggered disruptions in the COMPASS tokamak, post-disruptive runaway electron (RE) beams are generated occasionally. In this contribution, a relatively large set of discharges from the recent years is analysed in order to improve our understanding of the processes behind the beam generation. It seems that despite the low toroidal field applied in the discharges (typically 1.15 T) the magnetic perturbations may be small enough to allow the acceleration and confinement of the electrons. The influence of the different components and different sections of the frequency spectrum of the magnetic perturbations on the beam generation and RE beam current is examined. Fast visible camera images are also analysed. The relevance of COMPASS runaway electron experiments for large machines is discussed. Moreover, the potential of less common diagnostic tools (Cherenkov detector, vertical ECE, ...) to clarify the role of the pre-disruption fast electron population and the influence of prompt runaway electron losses in the current quench is discussed using the recent test measurements.
Keywords:
RE; massive gas injection (MGI); disruptions; HXR; ECE; fast cameras
Fulltext is available at external website.
RE beam generation in MGI disruptions on COMPASS.
In the experiments with the massive gas injection (MGI) triggered disruptions in the COMPASS tokamak, post-disruptive runaway electron (RE) beams are generated occasionally. In this contribution, a ...
Investigation of nanosecond pulsed corona-like discharge generated in deionized water.
Pongrác, Branislav; Šimek, Milan; Babický, Václav; Člupek, Martin; Lukeš, Petr
2017 - English
We employed techniques of time–resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water.
Keywords:
Underwater discharge; nanosecond pulsed discharge; time-resolved emission spectroscopy; time-resolved ICCD imaging
Available at various institutes of the ASCR
Investigation of nanosecond pulsed corona-like discharge generated in deionized water.
We employed techniques of time–resolved ICCD microscopy and spectroscopy to register basic morphologic and emission fingerprints of micro-discharges produced in deionized water.
Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
Ondáč, Peter; Mašláni, Alan; Hrabovský, Milan
2017 - English
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed camera, a high-voltage probe, and a hybrid water–argon plasma torch. The measurements were made for various values of ambient pressure, arc electric current, and argon flow rate. The measured plasma conductivity is in agreement with a model, camera observations and indirectly also with spectroscopy measurements. The procedure provides missing experimental data on the average plasma electrical conductivity and estimates average plasma temperature in the anode areas. The procedure can be theoretically used in every plasma torch where the anode arc attachment movement can be observed during a restrike process\n
Keywords:
DC arc plasma torch; Plasma electrical conductivity; Anode area
Available at various institutes of the ASCR
Measuring of Mean Plasma Electrical Conductivity in Anode Area of Plasma Torches with an External Anode
We developed a non-intrusive direct procedure of measuring an average electrical conductivity of a plasma volume in hot anode areas of those plasma torches. For our measurements, we used a high-speed ...
The role of microstructure on wettability of plasma sprayed yttria stabilized zirconia coatings
Komarov, P.; Čelko, L.; Remešová, M.; Skorokhod, K.; Jech, D.; Klakurková, L.; Slámečka, K.; Mušálek, Radek
2017 - English
Atmospheric plasma spraying utilizing initial powder materials in micrometric size has been successfully used for various applications in different fields of the industry over the past several decades. Nowadays, the new trend in plasma spraying is to use sub-micron or nano-sized powder feedstocks in the form of colloidal suspension. This relatively new technology enables to obtain specific types of dense vertically cracked, fully dense or columnar microstructure. The aim of this work is to investigate the influence of coatings microstructure and topography on its water wetting properties. Two different microstructures, i.e. lamellar and columnar, were sprayed from chemically the same yttria-stabillized zirconia (YSZ) ceramics powders by the means of conventional atmospheric plasma spray and suspension hybrid water stabilized plasma spray techniques, respectively. Microstructural and phase composition of the initial powders and as-sprayed coatings were investigated using optical microscopy, scanning electron microscopy and X-ray diffraction techniques. Topography of coatings surface was measured by means of non-contact optical profilometry. The YSZ coatings wettability was evaluated based on water droplet contact angle using Sessile droplet method. The coatings microstructure reveals the important role in the change of droplet contact angle, where lamellar microstructure was found close to hydrophilic-hydrophobic transition and columnar microstructure was found superhydrophobic
Keywords:
Contact angle; Plasma spraying; Sessile drop method; Water; Yttria stabilized zirconia
Available at various institutes of the ASCR
The role of microstructure on wettability of plasma sprayed yttria stabilized zirconia coatings
Atmospheric plasma spraying utilizing initial powder materials in micrometric size has been successfully used for various applications in different fields of the industry over the past several ...
Aspheric lenses test report
Lédl, Vít; Melich, Radek; Procháska, František; Steiger, Lukáš; Chiarini, M.; Cibin, L.
2017 - English
The scope of the document is to report the results of the tests on each of the 16 Aspheric Lenses + the 4 spare Aspheric Lens. \nIn particular, the tests performed on each lens are: reflectance of the coating on both the Aspheric Lens faces, interferometric profile of the Aspherical face and of the Spherical face of the Aspherical Lens.
Keywords:
aspherical lens; coating; interferometry
Available at various institutes of the ASCR
Aspheric lenses test report
The scope of the document is to report the results of the tests on each of the 16 Aspheric Lenses + the 4 spare Aspheric Lens. \nIn particular, the tests performed on each lens are: reflectance of the ...
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