Number of found documents: 535
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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. ...

Hurba, Oleksiy; Hrabovský, Milan
Ústav fyziky plazmatu, 2017

Sub-Nanosecond Laser Induced Plasma as Water Window Radiation Source.
Vrbová, M.; Vrba, Pavel
2017 - English
Laser plasma created in a krypton gas puff target is studied as a source of radiation in the water window spectral range (lambda= 2.3 - 4.4 nm). The spatial development of the plasma induced by a sub-nanosecond Nd:YAG laser pulse focused on the gas puff target is modeled using 2d RMHD code Z*. Space-time distributions of plasma quantities, namely electron temperature, electron density, mass density and plasma expansion velocity were evaluated. Instantaneous spectra during the laser pulse and during plasma decay period are also calculated. Temporal evolutions of the krypton ions relative populations prove that ions from Kr21+ and Kr22+ are responsible for dominant spectral intensity emitted at a wavelength around lambda= 3 nm. Evaluated time resolved spectra are compared with time integrated spectra obtained experimentally. Keywords: RMHD simulations; gas puff; laser plasma water window sources Available at various institutes of the ASCR
Sub-Nanosecond Laser Induced Plasma as Water Window Radiation Source.

Laser plasma created in a krypton gas puff target is studied as a source of radiation in the water window spectral range (lambda= 2.3 - 4.4 nm). The spatial development of the plasma induced by a ...

Vrbová, M.; Vrba, Pavel
Ústav fyziky plazmatu, 2017

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 ...

Matějková, M.; Čížek, Jan; Mušálek, Radek; Dlouhý, I.
Ústav fyziky plazmatu, 2017

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.

Pongrác, Branislav; Šimek, Milan; Babický, Václav; Člupek, Martin; Lukeš, Petr
Ústav fyziky plazmatu, 2017

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 ...

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
Ústav fyziky plazmatu, 2017

FÁZOVÁ STABILITA Y2O3 A W-Y2O3 ZPRACOVANÝCH METODOU MECHANICKÉHO LEGOVÁNÍ.
Illková, Ksenia; Vilémová, Monika; Lukáč, František
2017 - Czech
Kinetika fázových transformací B -> C jak v samotném Y2O3 tak i ve slitině W-xY2O3 je velmi důležitá vzhledem k použití těchto materiálů ve vysokoteplotních aplikacích. Chování vysokotlaké fáze B práškového Y2O3 indukované mletím a vlastnosti kompozitu W-Y2O3 byly studovány pomocí diferenční termální analýzy a rentgenové difrakce. Bylo zjištěno, že fázová stabilita je výrazně závislá na rychlosti ohřevu a na době setrvání na dané teplotě. Properties of milling-induced high-pressure B phase in Y2O3 and W-Y2O3 powders were studied by differential thermal analysis and X-Ray diffraction. It was found that phase stability strongly depends on the heating rate and holding time. Keywords: yttrium oxide; tungsten; milling; differential thermal analysis Available at various institutes of the ASCR
FÁZOVÁ STABILITA Y2O3 A W-Y2O3 ZPRACOVANÝCH METODOU MECHANICKÉHO LEGOVÁNÍ.

Kinetika fázových transformací B -> C jak v samotném Y2O3 tak i ve slitině W-xY2O3 je velmi důležitá vzhledem k použití těchto materiálů ve vysokoteplotních aplikacích. Chování vysokotlaké fáze B ...

Illková, Ksenia; Vilémová, Monika; Lukáč, František
Ústav fyziky plazmatu, 2017

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 ...

Ondáč, Peter; Mašláni, Alan; Hrabovský, Milan
Ústav fyziky plazmatu, 2017

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 ...

Kolegar, T.; Matoušek, M.; Vilémová, Monika; Starý, V.
Ústav fyziky plazmatu, 2017

Maksutovovy soustavy z Turnova
Rail, Zdeněk; Melich, Zbyněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
2017 - Czech
Tento referát popisuje vývoj a výrobu optických soustav, u kterých byl použit meniskový korektor Maksutova jako vstupní člen. Řada těchto vysoce kvalitních systémů byla v Turnově vyráběna od sedmdesátých let na několika pracovištích. V naší práci presentujeme zkušenosti s optickým designem, výrobou a konstrukcí meniskových dalekohledů a komor. This paper deals of a design and a manufacture of optical systems with the entrance meniscus corrector of Maksutov. Many of these high performance systems have been manufactured in several workshops in Turnov since Seventies. We present our experience with the optical design, manufacture and construction of the meniscus telescopes and cameras in this article. Keywords: Catadioptric system; meniscus corrector; spherochromatic aberration; spherical aberration; coma; astigmatism; Petzval´s curvature; MTF curve; glass dispersion curve Available at various institutes of the ASCR
Maksutovovy soustavy z Turnova

Tento referát popisuje vývoj a výrobu optických soustav, u kterých byl použit meniskový korektor Maksutova jako vstupní člen. Řada těchto vysoce kvalitních systémů byla v Turnově vyráběna od ...

Rail, Zdeněk; Melich, Zbyněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
Ústav fyziky plazmatu, 2017

Reflectivity of a mirror in XUV spectral region (46.9 nm).
Schmidt, Jiří; Koláček, Karel; Štraus, Jaroslav; Frolov, Oleksandr; Prukner, Václav; Melich, Radek; Psota, Pavel; Sobota, Jaroslav; Fořt, Tomáš
2017 - English
A focusing mirror as an optical element is used in our applications that require light collection (e.g. for laser ablation studies). A knowledge of the mirror reflectivity is important for determination of focused laser pulse energy, or for determination of local fluencies near the laser focus. The reflectivity of our spherical focusing mirror with(/without) multi-layer coating was measured. Reflection coefficients of this mirror in a long period of time are also reported. Further, the incidence-angle dependence of the XUV reflectivity of flat mirrors is presented as well. Keywords: Reflectivity of multilayer mirror in XUV range; aging of multilayer mirrors Available at various institutes of the ASCR
Reflectivity of a mirror in XUV spectral region (46.9 nm).

A focusing mirror as an optical element is used in our applications that require light collection (e.g. for laser ablation studies). A knowledge of the mirror reflectivity is important for ...

Schmidt, Jiří; Koláček, Karel; Štraus, Jaroslav; Frolov, Oleksandr; Prukner, Václav; Melich, Radek; Psota, Pavel; Sobota, Jaroslav; Fořt, Tomáš
Ústav fyziky plazmatu, 2017

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