• Title/Summary/Keyword: Longitudinal diffusion coefficients

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The study of electron transport coefficients in pure Ne by 2-term approximation of the Boltzmann equation (2항근사 볼츠만 방정식을 이용한 Ne분자가스의 전자수송계수의 해석)

  • Jeon, Byung-Hoon;Gang, Myung-Hee;Kim, Song-Gang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.05c
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    • pp.182-185
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    • 2001
  • The electron transport coefficients, the electron drift velocity W, the longitudinal diffusion coefficient $ND_L$ and $D_L/{\mu}$, in pure Ne were calculated over the wide E/N range from 0.01 to 300 Td at 1 Torr by two-term approximation of the Boltzmann equation for determination of electron collision cross sections set and for quantitative characteristic analysis of Ne molecular gas.

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Determination of Inelastic Collision Cross Sections for $C_{3}F_{8}$ Molecule by Multi-term Boltzmann Equation Analysis

  • Jeon, Byung-Hoon;Ha, Sung-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.934-941
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    • 2000
  • We measured the electron transport coefficients, the electron drift velocity W and the longitudinal diffusion coefficient $D_{L}$ in the 0.526% and 5.05% $C_{3}F_{8}$-Ar mixtures over the E/N range from 0.01 Td to 100 Td by the double shutter drift tube, and compared the measured results by Hunter et al. with those. We determined the inelastic collision cross sections for the $C_{3}F_{8}$ molecule by the comparison of the present measurements and the calculation of electron transport coefficients in the $C_{3}F_{8}$-Ar mixtures by using a multi-term Boltzmann equation analysis.

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A Simulation of Diffusion coefficients for electrons in $SF_6$-Ar Gas Mixtures (시뮬레이션에 의한 $SF_6$-Ar혼합기체의 확산계수)

  • Seong, Nak-Jin;Kim, Sang-Nam
    • Proceedings of the KIEE Conference
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    • 2006.10b
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    • pp.163-166
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    • 2006
  • Energy distribution function for electrons in $SF_6$-Ar mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range 30${\sim}$300(Td) by a two term Boltzmann equation and by a Monte Carlo Simulation using a set of electron cross sections determined by other authors, experimentally the electron swarm parameters for 0.2(%) and 0.5(%) $SF_6$-Ar mixtures were measured by time-of-flight(TOF) method, The results show that the deduced longitudinal diffusion coefficients and transverse diffusion coefficients agree reasonably well with theoretical for a rang of E/N values The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

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Diffusion Coefficients for Electrons in SF6-Ar Gas Mixtures by MCS-BEq (MCSBEq에 의한 SF6-Ar혼합기체의 확산계수)

  • Kim, Sang-Nam
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.3
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    • pp.125-129
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    • 2015
  • Energy distribution function for electrons in SF6-Ar mixtures gas used by MCS-BEq algorithm has been analysed over the E/N range 30~300[Td] by a two term Boltzmann equation and a Monte Carlo Simulation using a set of electron cross sections determined by other authors experimentally the electron swarm parameters for 0.2[%] and 0.5[%] $SF_6-Ar$ mixtures were measured by time-of-flight(TOF) method, The results show that the deduced longitudinal diffusion coefficients and transverse diffusion coefficients agree reasonably well with theoretical for a rang of E/N values. The results obtained from Boltzmann equation method and Monte Carlo simulation have been compared with present and previously obtained data and respective set of electron collision cross sections of the molecules.

Analysis of Electron Transport Coefficients in Low Voltage Air Circuit Breaker Using MCS and BE (몬테칼로 시뮬레이션과 볼츠만 방정식을 이용한 저전압 기중차단기의 전자수송계수 특성파악)

  • 하성철;서상현
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.16 no.2
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    • pp.168-172
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    • 2003
  • The electron transport coefficients in Air is analysed in range of E/Nvalues from 100~1000(Td) by a MCS and BE method. This paper have calculated W, ND$\sub$L/, ND$\sub$T/, Mean energy mixtures by N$_2$+O$_2$. The results gained that the values of the electron swarm parameters such as the electron drift velocity, longitudinal and transverse diffusion coefficients.

Radial and Circumferential Variations in Hygroscopicity and Diffusion Coefficients within a Tree Disk

  • Kang, Wook;Chung, Woo Yang;Eom, Chang Deuk;Han, Yeon Jung;Yeo, Hwan Myeong;Jung, Hee Suk
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.2
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    • pp.29-38
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    • 2007
  • This study was undertaken to investigate the variation of equilibrium moisture content (EMC) in transverse direction and three different directional (longitudinal, radial, and tangential) linear movements, and diffusion coefficients within a tree disc of Korean red pine (pinus densiflora). The EMC gradually increased in heartwood from pith. Therefore, the chemical components might differ even in heartwood and the radial variation in EMC might have a close relationship with the cellulose content within a cross section. The specific gravity increases gradually from pith and the porosity has not direct influence on the variation of EMC within a tree disk. Both the radial and tangential diffusion coefficients exhibited clear trend of increase from pith. The EMC change (${\Delta}EMC$) and tangential diffusion coefficient were close to be axisymmetrical but others were deviated from axisymmetry. The diffusion coefficient decreases with decreasing an activation energy and specific gravity, The diffusion coefficient increased with increasing ${\Delta}EMC$ and hygroscopicity of wood might be inversely proportional to the activation energy, The fJEMC may depend on the chemical constituents of cellulose, hemicellulose and lignin. As the number of sorption sites and sorption capacity of wood increase, therefore, it might be assumed that the hygroscopicity of wood increases while activation energy decreases. Modeling physico-mechanical behavior of wood, the variations should be considered to improve the accuracy.

Characteristics of Electron Transport in $SiH_4$ Gas used by MCS-BEq Algorithm (MCS-BEq 알고리즘에 의한 $SiH_4$ 기체의 전자수송특성)

  • Kim, Sang-Nam;Seong, Nak-Jin
    • Proceedings of the KIEE Conference
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    • 2006.10b
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    • pp.159-162
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    • 2006
  • In this paper energy distribution function in $SiH_4$ has been analysed over the E/N range 0.5${\sim}$300Td and Pressure value 0.5, 1.0, 2.5 Torr by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, diffusion coefficient, electron ionization, mean energy and the electron energy distribution function. The electron energy distribution function has been analysed in $SiH_4$ at E/N=30, 50Td for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results show that the deduced electron drift velocities, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients and mean energy agree reasonably well with theoretical for a rang of E/N values.

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A study on the electron energy diffusion function of the sulphur hexaflouride ($SF_6$ 가스의 전자에너지 분포함수에 관한 연구)

  • 김상남;유회영;서상현;박동화;하성철
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 1996.11a
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    • pp.134-139
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    • 1996
  • The electron energy distributions function were analysed in sulphur hexaflouride at E/N : 500~800(Td) for a case of non-equilibrium ion in the mean electron energy. This paper describes the electron transport characteristics in SF$_{6}$ gas calculated for range of E/N values from 150~800(Td) by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters. The results gained that the value of an electron swarm parameter such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N. The properties of electron avalanches in an electron energy non-equilibrium region.n.

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A Study on the electron energy diffusion function of the sulphur hexaflouride (SF_6 가스의 전자에너지 분포함수에 관한 연구)

  • ;金相南
    • The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.13 no.2
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    • pp.227-227
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    • 1999
  • The electron energy distributions function were analysed in sulphur hexaflouride at E/N : 500~800(Td) for a case of non-equilibrium region in the mean electron energy. This paper describes the electron transport characteristics in $SF_6$ gas calculated for range of E/N values from 150~800(Td) by the Monte Carlo simulation and Boltzmann equation method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters. The results gained that the value of ane1ctron swarm parameter such as the e1ectron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N. The properties of electron avalanches in an electron energy non-equilibrium region.

Ionization and Attachment Coefficients in CF4 (CF4 기체에서의 전리와 부착계수)

  • Kim, Sang-Nam
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.60 no.1
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    • pp.27-31
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    • 2011
  • In this paper, the electron transport characteristics in $CF_4$ has been analysed over the E/N range 1~300[Td] by a two-term approximation Boltzmann equation method and by a Monte Carlo simulation. The motion has been calculated to give swarm parameters for the electron drift velocity, longitudinal diffusion coefficient, the ratio of the diffusion coefficient to the mobility, electron ionization and attachment coefficients, effective ionization coefficient, mean energy, collision frequency and the electron energy distribution function. The electron energy distribution function has been analysed in $CF_4$ at E/N=5, 10, 100, 200 and 300[Td] for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The results of Boltzmann equation and Monte Carlo simulation have been compared with experimental data by Y. Nakamura and M. Hayashi. The swarm parameter from the swarm study are expected to serve as a critical test of current theories of low energy electron scattering by atoms and molecules, in particular, as well as crucial information for quantitative simulations of weakly ionized plasmas.