• Title/Summary/Keyword: Monte Carlo collision

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The Analysis of Electron Transport Characteristics in SiH4 Plasma (SiH4 플라즈마중의 전자수송특성 해석)

  • Lee, Hyoung-Yoon;Ha, Sung-Chul;Kim, Dae-Yeon
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.925-928
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    • 1998
  • In this paper, the electron transport characteristics in SiH4 has been analysed over the E/N range 0.5300[Td] and Pressure value 0.5, 1, 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 SiH4 at E/N=30, 50[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 Pollock, Ohmori, cottrell and Walker.

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Calculation of ion distribution in an RF plasma etching system using monte carlo methods (몬테카를로 계산 방식에 의한 RF 플라즈마 에칭 시스템에서의 이온 분포 계산)

  • 반용찬;이제희;윤상호;권오섭;김윤태;원태영
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.5
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    • pp.54-62
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    • 1998
  • In a plasma etching system, ions become an important parameter in determining the wafer topography which depends on both the physical sputtering mechanism and the chemically enhanced reaction. this paper reports the energy and angular distributions of ions across the plasma sheath using a monte carlo method. The ion distribution is mainly affected by the magnitude of the sheath voltage and by the collision in the sheath. Furthemore, the local potential distribution in a plamsa sheath has been determined by solving the poisson's equation. In th is work, ionic collisions were cosidered in terms of both charge exchange and momentum transfer. The three-dimensional distributions of ions were calculated with varying the input process conditions in the plasma reactor.

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Diffusion coefficients of electrons in SF6-Ar Mixtures Gas used by MCS-BEq Algorithm (SF6-Ar 혼합기체(混合氣體)의 MCS-BE_q알고리즘에 의한 확산계수)

  • Kim, Sang-Nam;Ha, Sung-Chul
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.1150-1153
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    • 2004
  • Diffusion coefficients Of electrons in SF6-Ar mixtures gas used by MCS- BEq algorithm has been analysed over the E/N range 30300(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[%] SF6-Ar mixtures were measured by time-of-flight(TOF) method, 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 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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Rarefied Gas Flows in Spiral Channels of a Disk-Type Drag Pump (원판형 드래그펌프내의 희박기체유동)

  • Hwang, Young-Kyu;Heo, Joons-Sik
    • 유체기계공업학회:학술대회논문집
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    • 2000.12a
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    • pp.82-87
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    • 2000
  • The direct simulation Monte Carlo (DSMC) method is applied to investigate the flow field of a disk-type drag pump. The pumping channels are cut on both sides of a rotating disk. The rotor has 10 Archimedes' spiral blades. In the present DSMC method, the variable hard sphere model is used as a molecular model, and the no time counter method is employed as a collision sampling technique. For simulation of diatomic gas flows, the Larsen-Borgnakke phenomenological model is adopted to redistribute the translational and internal energies.

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Effect of Vertical Clearance Between a Rotor and Stater of a Disk-Type Drag Pump on the Performance (원판형 드래그펌프 회전자와 고정자 사이의 간극이 성능에 미치는 영향)

  • Kwon, Myoung-Keun;Hwang, Young-Kyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.12
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    • pp.1501-1510
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    • 2004
  • The pumping characteristics of a single-stage disk-type drag pump (DTDP) are calculated for the variation of the vertical clearance between a rotor and stator by the three-dimensional direct simulation Monte Carlo (DSMC) method. The gas flow mainly belongs to the molecular transition flow region. Spiral channels of a DTDP are cut on the both the upper and lower sides of a rotating disk, but a stationary disk is planar. The interaction between molecules is described by the variable hard-sphere model. The no time counter method is used as a collision sampling technique. The vertical clearance has a significant effect on the pumping performance. Experiments are performed under the outlet pressure range of 0.4∼533 Pa. When the numerical results are compared with the experimental data, the numerical results agree well quantitatively

Particle Simulation on the Effect of Grid Cathode Geometry in SCBF Device (SCBF 장치에서 그리드 음극 구조의 영향에 대한 입자 시뮬레이션)

  • Ju, Heung-Jin;Park, Jeong-Ho;Ko, Kwang-Cheol
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.8
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    • pp.742-747
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    • 2007
  • In 2-dimensional SCBF (Spherically Convergent Beam Fusion) device, the effect on neutron production rate of the grid cathode geometry was simulated. The motion of Particles was tracked using Monte Carlo Method including the atomic and molecular collision processes and potential distribution was calculated by Finite Element Method, Main processes of the discharge were the ionization of D2 by fast D2+ion. As the number of cathode rings was small and the size of grid cathode decreased, the ion current increased and neutron production rate will also increase. The star mode discharge which is a very important characteristic in SCBF device, was confirmed by the ionization position.

Analysis of electron transport properties in SF6+N2 mixtures gas used by MCS-BE (MCS-BE에 의한 SF6+N2 혼합기체의 전자수송특성 해석)

  • 서상현;하성철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.696-699
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    • 1999
  • The electron transport coefficients in SF6+N2 gas is analysed in range of E/N values from 100~900(Td) by a Monte Carlo simulation and Boltzmann method, using a set of electron collision cross sections determined by the authors. The result of the Monte Carlo simulation such as electron drift velocity, ionization and electron attachment coefficients, longitudinal and transverse diffusion coefficients in nearly agreement with the respective experimental and theoretical for a range of E/N.

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Electron Transport Characteristics in SiH4 by MCS-BEq (MCS-BEq에 의한 SiH4 전자수송특성(電子輸送特性))

  • Seong, Nak-Jin;Kim, Sang-Nam
    • Proceedings of the KIEE Conference
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    • 2005.10a
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    • pp.97-100
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    • 2005
  • This paper describes the electron transport characteristics in SiH4 has been analysed over the E/N range 0.5300[Td] and Pressure value 0.5, 1, 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 SiH4 at E/N=30, 50[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 Pollock, Ohmori, cottrell and Walker.

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OPTIMIZATION OF A DRIVER-SIDE AIRBAG USING KRIGING AND TABU SEARCH METHODS (크리깅과 타부탐색법을 이용한 운전석 에어백의 최적설계)

  • Kim, Jeung-Hwan;Lee, Kwom-Hee;Joo, Won-Sik
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1035-1040
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    • 2004
  • In the proto design stage of a new car, the performance of an occupant protection system is often evaluated by CAE instead of the real test. CAE predicts and recommends the appropriate design values hence reducing the number of the real tests. However, the existing researches using CAE in predicting the performances do not consider the uncertainties of parameters, in which inconsistency between the actual test results and CAE exists. In this research, the optimization procedure of a protection system such as airbag and load limiter is suggested for the frontal collision. The DACE modeling known as Kriging interpolation is introduced to obtain the meta model of the system followed by the tabu search method to determine a global optimum. Finally, the distribution of a suggested design is determined through the Monte-Carlo Simulation.

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Removal trajectory generation for LEO satellites and analysis collision probability during removal maneuver (저궤도 위성의 폐기경로 생성 및 폐기기동 중 충돌위험 분석)

  • Seong, Jae-Dong;Min, Chan-Oh;Jeong, Soon-Woo;Lee, Dae-Woo;Cho, Kyeum-Rae;Kim, Hae-Dong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.40 no.4
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    • pp.354-363
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    • 2012
  • Now there are a lot of expired satellites or space debris around the earth orbit and they threaten the operating satellites and manned space missions. KOMPSAT-2 that scheduled to operate the mission by July, 2013 also has to consider the space debris. This paper introduces the '25 years rules' that must be re-entered within 25 years after the space mission for LEO satellites and describes the removal trajectory design that satisfies the '25 years rules' and minimizes fuel consumption. And this paper suggests monte-carlo simulation for risk analysis that causes the approaching object to the removal trajectory. The result shows that the collision probability of worst case presents 6.0741E-07 and it need to more analysis about precise satellite safety during removal maneuver because there is no information about the object size that approaching to the satellites.