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Masaru Hori - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal behaviors of Absolute Density of atomic oxygen in a planar type of ar o2 non equilibrium atmospheric pressure plasma jet
Plasma Sources Science and Technology, 2014Co-Authors: Fengdong Jia, Kenji Ishikawa, Keigo Takeda, Hiroyuki Kano, Jagath S Kularatne, Hiroki Kondo, Makoto Sekine, Masaru HoriAbstract:A method combining of two-photon absorption laser-induced fluorescence and vacuum ultra-violet absorption spectroscopy is constructed and used to get the fine spatial distribution of O generated by a planar type of Ar/O2 non-equilibrium atmospheric-pressure plasma jet. The O Density in the quasi-uniform region, which occupies about 80% of the total plasma width, is as high as 1015 cm−3. The lifetime of O is estimated to be about 360 ± 60 µs. The loss of O atoms is due to the three-body reaction of O + O2 + Ar → O3 + Ar confirmed by a simple calculation with a few rate equations. The results are very useful for the simulation of Ar/O2 plasmas, the design of large-scale planar plasma jets and the development of their potential applications.
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effect of gas flow on transport of o 3pj atoms produced in ac power excited non equilibrium atmospheric pressure o2 ar plasma jet
Journal of Physics D, 2013Co-Authors: Keigo Takeda, Fengdong Jia, Kenji Ishikawa, Hiroyuki Kano, Makoto Sekine, Masanori Kato, Masaru HoriAbstract:The Spatial distribution of O (3Pj) atoms emitted from a non-equilibrium atmospheric-pressure O2/Ar plasma jet in ambient N2 gas has been measured by using the vacuum ultraviolet absorption spectroscopy. In remote regions of the plasma, the Absolute Density of O (3Pj) atoms for a total gas flow rate of 1 slm decreased from 4.1 × 1014 to 1.5 × 1013 cm−3 as the distance from the main discharge region increased from 10 to 16 mm and that for 5 slm decreased from 7.7 × 1014 to 2.0 × 1014 cm−3. The reduction ratio thus changed from 0.037 to 0.259 with increasing total gas flow rate. Although loss of O (3Pj) atoms occurs frequently due to the influence of N2 or nitrogen oxide species produced by the inflow of ambient gas, it is found that the gas flow velocity is a very important factor for the transport of the active species to longer distances from the plasma, and it determines the material processing performance for a non-equilibrium atmospheric-pressure O2/Ar plasma jet.
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development of vacuum ultraviolet absorption spectroscopy technique employing nitrogen molecule microdischarge hollow cathode lamp for Absolute Density measurements of nitrogen atoms in process plasmas
Journal of Vacuum Science and Technology, 2001Co-Authors: Seigou Takashima, Akihiro Kono, Masafumi Ito, Masaru Hori, Toshio Goto, Shigeo Arai, Katsumi YonedaAbstract:We have developed a vacuum ultraviolet absorption spectroscopy (VUVAS) technique employing a high-pressure nitrogen molecule (N2) microdischarge hollow cathode lamp (N2 MHCL) as a light source of the atomic nitrogen (N) resonance lines for measuring Absolute N densities in process plasmas. The estimations of self-absorption and the emission line profiles of the N2 MHCL, which are necessary for Absolute N Density determination, were carried out. The measurement of Absolute N densities have been demonstrated for an inductively coupled N2 plasma using the VUVAS system employing the N2 MHCL.
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Vacuum ultraviolet absorption spectroscopy employing a microdiacharge hollow-cathode lamp for Absolute Density measurements of hydrogen atoms in reactive plasmas
Applied Physics Letters, 1999Co-Authors: Seigou Takashima, Akihiro Kono, Masafumi Ito, Masaru Hori, Toshio Goto, Katsumi YonedaAbstract:We have developed a measurement technique for Absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge hollow-cathode lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the Absolute H-atom Density in an inductively coupled H2 plasma.
Alexander Karamanov - One of the best experts on this subject based on the ideXlab platform.
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sinter crystallisation in the diopside albite system part i formation of induced crystallisation porosity
Journal of The European Ceramic Society, 2006Co-Authors: Alexander KaramanovAbstract:Abstract The sinter-crystallisation was investigated in three model glasses ( G1 , G2 and G3 ) belonging to the diopside–albite system and forming between 30 and 60% diopside, respectively. The effect of bulk crystallisation on the sintering was studied by the addition of 0.7 wt.% Cr 2 O 3 as nucleating agent to the G2 glass. The degree of sintering was evaluated by the variation of the apparent Density while the crystallisation, by the increasing of the Absolute Density. The structure and morphology of the sintered glass-ceramics was observed by SEM-BSE. The results highlighted that the densification is not influenced by the variation of the composition among the three glasses but is inhibited by the diopide formation in G2 - Cr where bulk nucleation takes place. It was shown that, due to the volume variation related to the diopside crystallisation, a spherical intragranular pores were formed in the glass-ceramics. The amounts of this porosity, named induced crystallisation porosity, increased as function of the crystallisation trend.
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sinter crystallisation in the diopside albite system part i formation of induced crystallisation porosity
Journal of The European Ceramic Society, 2006Co-Authors: Alexander KaramanovAbstract:Abstract The sinter-crystallisation was investigated in three model glasses ( G1 , G2 and G3 ) belonging to the diopside–albite system and forming between 30 and 60% diopside, respectively. The effect of bulk crystallisation on the sintering was studied by the addition of 0.7 wt.% Cr 2 O 3 as nucleating agent to the G2 glass. The degree of sintering was evaluated by the variation of the apparent Density while the crystallisation, by the increasing of the Absolute Density. The structure and morphology of the sintered glass-ceramics was observed by SEM-BSE. The results highlighted that the densification is not influenced by the variation of the composition among the three glasses but is inhibited by the diopide formation in G2 - Cr where bulk nucleation takes place. It was shown that, due to the volume variation related to the diopside crystallisation, a spherical intragranular pores were formed in the glass-ceramics. The amounts of this porosity, named induced crystallisation porosity, increased as function of the crystallisation trend.
Harald Kucharek - One of the best experts on this subject based on the ideXlab platform.
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interstellar neutral helium in the heliosphere from ibex observations vi the he Density and the ionization state in the very local interstellar matter
The Astrophysical Journal, 2019Co-Authors: Maciej Bzowski, Priscilla C. Frisch, A Galli, Jerzy Grygorczuk, Jacob Heerikhuisen, M A Kubiak, S. A. Fuselier, Andrzej Czechowski, Harald KucharekAbstract:Interstellar neutral gas atoms penetrate the heliopause and reach 1 au, where they are detected by Interstellar Boundary Explorer (IBEX). The flow of neutral interstellar helium through the perturbed interstellar plasma in the outer heliosheath (OHS) results in the creation of a secondary population of interstellar He atoms, the so-called Warm Breeze, due to charge exchange with perturbed ions. The secondary population brings the imprint of the OHS conditions to the IBEX-Lo instrument. Based on a global simulation of the heliosphere with measurementbased parameters and detailed kinetic simulation of the filtration of He in the OHS, we find the number Density of the interstellar He+ population to be (8.98±0.12)×10−3 cm−3. With this, we obtain the Absolute Density of interstellar H+ as 5.4×10−2 cm−3 and that of electrons as 6.3×10−2 cm−3, with ionization degrees of 0.26 for H and 0.37 for He. The results agree with estimates of the parameters of the Very Local Interstellar Matter obtained from fitting the observed spectra of diffuse interstellar EUV and the soft X-ray background.
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Interstellar Neutral Helium in the Heliosphere from IBEX Observations. VI. The He + Density and the Ionization State in the Very Local Interstellar Matter
The Astrophysical Journal, 2019Co-Authors: Maciej Bzowski, Priscilla C. Frisch, A Galli, Jerzy Grygorczuk, Jacob Heerikhuisen, M A Kubiak, S. A. Fuselier, Andrzej Czechowski, Harald KucharekAbstract:Interstellar neutral gas atoms penetrate the heliopause and reach 1 au, where they are detected by Interstellar Boundary Explorer (IBEX). The flow of neutral interstellar helium through the perturbed interstellar plasma in the outer heliosheath (OHS) results in the creation of a secondary population of interstellar He atoms, the so-called Warm Breeze, due to charge exchange with perturbed ions. The secondary population brings the imprint of the OHS conditions to the IBEX-Lo instrument. Based on a global simulation of the heliosphere with measurementbased parameters and detailed kinetic simulation of the filtration of He in the OHS, we find the number Density of the interstellar He+ population to be (8.98±0.12)×10−3 cm−3. With this, we obtain the Absolute Density of interstellar H+ as 5.4×10−2 cm−3 and that of electrons as 6.3×10−2 cm−3, with ionization degrees of 0.26 for H and 0.37 for He. The results agree with estimates of the parameters of the Very Local Interstellar Matter obtained from fitting the observed spectra of diffuse interstellar EUV and the soft X-ray background.
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interstellar neutral helium in the heliosphere from ibex observations vi the he Density and the ionization state in the very local interstellar matter
arXiv: Solar and Stellar Astrophysics, 2019Co-Authors: Maciej Bzowski, Priscilla C. Frisch, A Galli, Jerzy Grygorczuk, Jacob Heerikhuisen, M A Kubiak, S. A. Fuselier, Andrzej Czechowski, Harald KucharekAbstract:Interstellar neutral gas atoms penetrate the heliopause and reach 1~au, where they are detected by IBEX. The flow of neutral interstellar helium through the perturbed interstellar plasma in the outer heliosheath (OHS) results in creation of the secondary population of interstellar He atoms, the so-called Warm Breeze, due to charge exchange with perturbed ions. The secondary population brings the imprint of the OHS conditions to the IBEX-Lo instrument. Based on a global simulation of the heliosphere with measurement-based parameters and detailed kinetic simulation of the filtration of He in the OHS, we find the number Density of interstellar He$^+$ population at $(8.98\pm 0.12)\times 10^{-3}$~cm$^{-3}$. With this, we obtain the Absolute Density of interstellar H$^+$ $5.4\times 10^{-2}$~cm$^{-3}$ and electrons $6.3\times 10^{-2}$~cm$^{-3}$, and ionization degrees of H 0.26 and He 0.37. The results agree with estimates of the Very Local Interstellar Matter parameters obtained from fitting the observed spectra of diffuse interstellar EUV and soft X-Ray background.
Hideki Matsumura - One of the best experts on this subject based on the ideXlab platform.
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direct detection of h atoms in the catalytic chemical vapor deposition of the sih4 h2 system
Journal of Applied Physics, 2002Co-Authors: Hironobu Umemoto, Kentaro Ohara, Daisuke Morita, Yoshitaka Nozaki, Atsushi Masuda, Hideki MatsumuraAbstract:The Absolute densities of H atoms produced in catalytic chemical vapor deposition (Cat-CVD or hot-wire CVD) processes were determined by employing two-photon laser-induced fluorescence and vacuum ultraviolet absorption techniques. The H-atom Density in the gas phase increases exponentially with increases in the catalyzer temperature in the presence of pure H2. When the catalyzer temperature was 2200 K, the Absolute Density in the presence of 5.6 Pa of H2 (150 sccm in flow rate) was as high as 1.5×1014 cm−3 at a point 10 cm from the catalyzer. This Density is one or two orders of magnitude higher than those observed in typical plasma-enhanced chemical vapor-deposition processes. The H-atom Density decreases sharply with the addition of SiH4. When 0.1 Pa of SiH4 was added, the steady-state Density decreased to 7×1012 cm−3. This sharp decrease can primarily be ascribed to the loss processes on chamber walls.
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identification of si and sih in catalytic chemical vapor deposition of sih4 by laser induced fluorescence spectroscopy
Journal of Applied Physics, 2000Co-Authors: Yoshitaka Nozaki, Hironobu Umemoto, Atsushi Masuda, Koichi Kongo, Toshihiko Miyazaki, Makiko Kitazoe, Katsuhiko Horii, Hideki MatsumuraAbstract:Radical species produced in catalytic chemical vapor deposition (CVD), often called hot-wire CVD, processes were identified by using a laser induced fluorescence technique. Ground state Si atoms could be detected at low pressures where collisional processes in the gas phase could be ignored. The electronic temperature of Si atoms just after the formation on the catalyzer (tungsten) surfaces was 1320±490 K, when the catalyzer temperature was 2300 K. By the addition of 0.5 Pa of Ar, the electronic temperature was lowered down to 450±30 K. The Absolute Density of Si atoms was 3±1×109 cm−3 at 10 cm below the catalyzer when the flow rate and the pressure of SiH4 were 0.5 sccm and 4 mPa, respectively. This Density is just 0.3% of that of the parent SiH4 molecules. However, since the decay rate of Si atoms is fast, it can be concluded that atomic silicon is one of the major products on the heated catalyzer surfaces. SiH radicals could also be detected, but the production rate of this species is two orders of magnitude less than that of Si atoms. It was also discovered that volatile SiH4 molecules are produced by the atomic hydrogen attack on the amorphous silicon deposited on the chamber walls.Radical species produced in catalytic chemical vapor deposition (CVD), often called hot-wire CVD, processes were identified by using a laser induced fluorescence technique. Ground state Si atoms could be detected at low pressures where collisional processes in the gas phase could be ignored. The electronic temperature of Si atoms just after the formation on the catalyzer (tungsten) surfaces was 1320±490 K, when the catalyzer temperature was 2300 K. By the addition of 0.5 Pa of Ar, the electronic temperature was lowered down to 450±30 K. The Absolute Density of Si atoms was 3±1×109 cm−3 at 10 cm below the catalyzer when the flow rate and the pressure of SiH4 were 0.5 sccm and 4 mPa, respectively. This Density is just 0.3% of that of the parent SiH4 molecules. However, since the decay rate of Si atoms is fast, it can be concluded that atomic silicon is one of the major products on the heated catalyzer surfaces. SiH radicals could also be detected, but the production rate of this species is two orders of mag...
Katsumi Yoneda - One of the best experts on this subject based on the ideXlab platform.
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development of vacuum ultraviolet absorption spectroscopy technique employing nitrogen molecule microdischarge hollow cathode lamp for Absolute Density measurements of nitrogen atoms in process plasmas
Journal of Vacuum Science and Technology, 2001Co-Authors: Seigou Takashima, Akihiro Kono, Masafumi Ito, Masaru Hori, Toshio Goto, Shigeo Arai, Katsumi YonedaAbstract:We have developed a vacuum ultraviolet absorption spectroscopy (VUVAS) technique employing a high-pressure nitrogen molecule (N2) microdischarge hollow cathode lamp (N2 MHCL) as a light source of the atomic nitrogen (N) resonance lines for measuring Absolute N densities in process plasmas. The estimations of self-absorption and the emission line profiles of the N2 MHCL, which are necessary for Absolute N Density determination, were carried out. The measurement of Absolute N densities have been demonstrated for an inductively coupled N2 plasma using the VUVAS system employing the N2 MHCL.
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Vacuum ultraviolet absorption spectroscopy employing a microdiacharge hollow-cathode lamp for Absolute Density measurements of hydrogen atoms in reactive plasmas
Applied Physics Letters, 1999Co-Authors: Seigou Takashima, Akihiro Kono, Masafumi Ito, Masaru Hori, Toshio Goto, Katsumi YonedaAbstract:We have developed a measurement technique for Absolute H-atom densities in process plasmas using vacuum ultraviolet absorption spectroscopy employing a high-pressure microdischarge hollow-cathode lamp (MHCL) as a Lyman α (Lα, 121.6 nm) emission light source. Characterization of the Lα emission-line profile could be simplified by using a high-pressure discharge at about 1 atm. The effect of self-absorption in the MHCL was reduced to an insignificant level by decreasing the H2 partial pressure. The contribution of the collisional broadening to the Lα emission profile was estimated from the saturation characteristics of the absorption intensity when the optical thickness of the plasma was varied. The technique was applied to the measurement of the Absolute H-atom Density in an inductively coupled H2 plasma.
