• Title/Summary/Keyword: collision cross-section

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Electron Energy Distribution Function in SF6-He Gas by Simulation (시뮬레이션에 의한 SF6-He 혼합기체에서 전자에너지 분포함수)

  • Kim, Sang-Nam
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.1
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    • pp.19-23
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    • 2014
  • This paper describes the electron transport characteristics in $SF_6$-He gas calculated E/N values 0.1~700[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 obtained by TOF method. This study gained the values of the electron swarm parameters such as the electron drift velocity, the electron ionization or attachment coefficients, longitudinal and transverse diffusion coefficients for $SF_6$-He gas at a range of E/N. A set of electron collision cross section has been assembled and used in Monte Carlo simulation to predict values of swarm parameters. The result of Boltzmann equation and Monte Carlo Simulation has been compared with experimental data by Ohmori, Lucas and Carter. The swarm parameter from the swarm study are expected to sever as a critical test of current theories of low energy scattering by atoms and molecules.

The Study of the insulation Charateristic in $SF_6$+$N_2$ mixture gas ($SF_6$+$N_2$ 혼합기체의 절연특성에 관한 연구)

  • 박명진;전병훈;하성철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.592-595
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    • 2000
  • The electron transport coefficients in $SF_6$+$N_2$ gas is analyzed in range of E/P values from 70~240(V/cm $Torr^{-1}$) at 2$0^{\circ}C$ by Boltzmann method that using set of electron collision cross sections determined by authors. The result of this Boltzmann simulation such as ionisation coefficient, attachment coefficient, effective ionisation coefficient and breakdown voltage are in nearly agreement with the respective experimental and theoretical for a range of E/P.

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Monte carlo simulation for electron transport characteristics in sulphur hexaflouride ($SF_6$ 가스의 전자수송특성에 관한 몬테칼로시뮬레이션)

  • 하성철;서상현
    • Electrical & Electronic Materials
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    • v.9 no.7
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    • pp.660-667
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    • 1996
  • The electron transport characteristics in $SF_6$ gas is calculated for range of E/N values from 150 -800(Td) by the Monte Carlo simulation using a set of electron collision cross sections determined by the authors. The results suggest 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 in nearly agreement with the respective experimental and theoretical for a range of E/N. The electron energy distributions function were analysed in sulphur hexaflouride at E/N:500 and 800(Td) for a case of the equilibrium region in the mean electron energy. The validity of the results obtained has been confirmed by a Time of Flight method also investigated as a set of electron collision cross section for sulphur Hexaflouride.

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Basic study on the gas discharge panel for LCD and PDP (PDP와 LCD에서의 가스방전 페널에 대한 기초연구)

  • Song, Byoung-Doo;Ha, Sung-Chul;Jeon, Byung-Hoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.11a
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    • pp.554-557
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    • 2003
  • This paper describes the information for quantitative simulation of weakly ionized plasma. We should grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. In this paper, electron swarm parameter in He+Xe and Ar+He mixture gas calculated for range E/N values $0.01{\sim}500$ [Td] at the temperature is 300 [K] and pressure is 1 [Torr], using a set of electron collision cross sections determined by the authors, and using a method of Backward Prolongation by two term approximation Boltzmann equation method, for basic study on the gas discharge panel.

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Verification of a two-step code system MCS/RAST-F to fast reactor core analysis

  • Tran, Tuan Quoc;Cherezov, Alexey;Du, Xianan;Lee, Deokjung
    • Nuclear Engineering and Technology
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    • v.54 no.5
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    • pp.1789-1803
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    • 2022
  • RAST-F is a new full-core analysis code based on the two-step approach that couples a multi-group cross-section generation Monte-Carlo code MCS and a multi-group nodal diffusion solver. To demonstrate the feasibility of using MCS/RAST-F for fast reactor analysis, this paper presents the coupled nodal code verification results for the MET-1000 and CAR-3600 benchmark cores. Three different multi-group cross-section calculation schemes are employed to improve the agreement between the nodal and reference solutions. The reference solution is obtained by the MCS code using continuous-energy nuclear data. Additionally, the MCS/RAST-F nodal solution is verified with results based on cross-section generated by collision probability code TULIP. A good agreement between MCS/RAST-F and reference solution is observed with less than 120 pcm discrepancy in keff and less than 1.2% root-mean-square error in power distribution. This study confirms the two-step approach MCS/RAST-F as a reliable tool for the three-dimensional simulation of reactor cores with fast spectrum.

Characteristics of Droplet Properties in the Two-Phase Spray into a Subsonic Cross Flow

  • Lee, I.C.;Cho, W.J.;Koo, J.Y.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.03a
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    • pp.358-363
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    • 2008
  • The spray cross-section characteristics of two-phase spray that using external-mixing nozzle injected into a subsonic cross flow were experimentally studied with various ALR ratio that is $0{\sim}59.4%$. Suction type wind tunnel was used and experiments were conducted to ambient environment. Several plain orifice nozzles with L/d of 30 and orifice diameter of 0.5 mm and orifice length 1.5 mm were tested. Free stream velocity profiles at the injection location were measured using hot wire. Spray images were captured to study collision point and column trajectory. Phase Doppler particle analyzer(PDPA) was utilized to quantitatively measuring droplet SMD, volume flux. Measuring probe of PDPA positions was moved 3-way transverse machine. SMD distributions were layered structure and peaked at the top of the spray plume and low value at bottom of the spray. Volume flux of spray was distributed to the two side region and volume flux quantity decreased when ALR ratio increased. It was found that the perpendicularly injected two-phase spray jet of external mixing into a cross flow showing that mistlike spray moved away from the test section bottom region.

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Coriolis Coupling Influence on the H+LiH Reaction

  • Zhai, Hongsheng;Li, Wenliang;Liu, Yufang
    • Bulletin of the Korean Chemical Society
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    • v.35 no.1
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    • pp.151-157
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    • 2014
  • We have reported the reaction probability, integral reaction cross section, and rate constant for the title system calculated with the aid of a time-dependent wave packet approach. The ab initio potential energy surface (PES) of Prudente et al. (Chem. Phys. Lett. 2009, 474, 18) is employed for the purpose. The calculations are carried out over the collision energy range of 0.05-1.4 eV for the two reaction channels of H + LiH ${\rightarrow}$ Li + $H_2$ and $H_b$ + $LiH_a$ ${\rightarrow}$ $LiH_b$ + $H_a$. The Coriolis coupling (CC) effect are taken into account. The importance of including the Coriolis coupling quantum scattering calculations are revealed by the comparison between the Coriolis coupling and the centrifugal sudden (CS) approximation calculations.

Development of a fast reactor multigroup cross section generation code EXUS-F capable of direct processing of evaluated nuclear data files

  • Lim, Changhyun;Joo, Han Gyu;Yang, Won Sik
    • Nuclear Engineering and Technology
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    • v.50 no.3
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    • pp.340-355
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    • 2018
  • The methods and performance of a fast reactor multigroup cross section (XS) generation code EXUS-F are described that is capable of directly processing Evaluated Nuclear Data File format nuclear data files. RECONR of NJOY is used to generate pointwise XS data, and Doppler broadening is incorporated by the Gauss-Hermite quadrature method. The self-shielding effect is incorporated in the ultrafine group XSs in the resolved and unresolved resonance ranges. Functions to generate scattering transfer matrices and fission spectrum matrices are realized. The extended transport approximation is used in zero-dimensional calculations, whereas the collision probability method and the method of characteristics are used for one-dimensional cylindrical geometry and two-dimensional hexagonal geometry problems, respectively. Verification calculations are performed first for various homogeneous mixtures and cylindrical problems. It is confirmed that the spectrum calculations and the corresponding multigroup XS generations are performed adequately in that the reactivity errors are less than 50 pcm with the McCARD Monte Carlo solutions. The nTRACER core calculations are performed with the EXUS-F-generated 47 group XSs for the two-dimensional Advanced Burner Reactor 1000 benchmark problem. The reactivity error of 160 pcm and the root mean square error of the pin powers of 0.7% indicate that EXUF-F generates properly the broad-group XSs.

Memory of Initial States in Scattering over Attractive Potential Energy Surface for Atom-Diatom Collisions

  • Seung-Ho Choi;Hyung-Rae Kim
    • Bulletin of the Korean Chemical Society
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    • v.12 no.4
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    • pp.423-429
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    • 1991
  • Global and local memory functions, defined by Quack and Troe, were calculated for the rotationally inelastic collision of O + SO(v, j)→ [O--S--O]→O + SO(v, j'). It is seen to decrease steadily as total energy increases. Distribution of scattering cross section over product rotational states also shows the decreasing memory of initial state as total energy is increased. These results are interpreted in terms of energy scrambling at high energy due to the availability of more phase space and also the influence of strong dynamical constraints.

Determination of the initial cross-sections for the $C_4F_6$ molecule from the electron drift velocity ($C_4F_6$-Ar혼합기체에서의 Plasma Discharge Simulation을 위한 $C_4F_6$ 초기단면적 결정)

  • Lee, Kyung-Yeob;Jeon, Byung-Hoon
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1544-1545
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    • 2011
  • For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. Processing plasma etching of semiconductor, and research are being used in the etching source $C_4F_6$ gas may be used by itself and mixed with other gases are also used. However, the molecular gas $C_4F_6$ study on the characteristics of the electron transport and the cross-sectional area of the decision is still lacking. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients. And to understand and interpret physical properties of the ionization coefficient ${\alpha}$/N, and the attachment coefficient ${\eta}$/N in $C_4F_6$ gas.

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