• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.18-22
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• 2013

This paper describes the information for quantitative simulation of weakly ionized plasma. We must grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. Using quantitative simulations of weakly ionized plasma, we can analyze gas characteristic. In this paper, the electron transport characteristic in $CH_4$ has been analysed over the E/N range 0.1~300[Td], at the 300[$_{\circ}\;K$] by the two term approximation Boltzmann equation method and Monte Carlo Simulation. Boltzmann equation method has also been used to predict swarm parameter using the same cross sections as input. The behavior of electron has been calculated to give swarm parameter for the electron energy distribution function has been analysed in $CH_4$ at E/N=10, 100 for a case of the equilibrium region in the mean energy. 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.

• Electrical & Electronic Materials
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• v.10 no.4
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• pp.342-348
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• 1997

In this paper, the behavior of electron swarm parameters and energy distribution function of the discharge under high E/N condition in e$^{-10}$ -CF$_{4}$ gas have been analysed over the E/N range from 1-300(Td) by the MCS and BEq methods using set of electron collision cross section determined by the authors. The swarm parameters and energy distribution function have been calculated for the pulsed Townsend, steady-state Townsend and Time of Flight methods. The results gained that the value of electron swarm parameters such as the electron drift velocity, the electron ionization and attachment coefficients and longitudinal diffusion coefficients in agreement with the experimental and theoretical data for a range of E/N. The electron energy distribution function has been explained and analysed in e$^{-10}$ -CF$_{4}$ at E/N : 5, 10, 100, 200, 300(Td) for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The validity of the results has been confirmed by TOF and SST methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.104-108
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• 2008

Accurate sets of electron collision cross sections and the electron transport coefficients for atoms and molecules are necessary for quantitative understanding of plasma phenomena Kr and Xe atom are used in many industrial applications, such as in PDP and fluorescent induction lamps(FILs). Therefore, we analysed and calculated the electron transport coefficients, the electron drift velocity W, the longitudinal and transverse diffusion coefficient $ND_L$ and $ND_T$, and the ionization coefficient $\alpha$/N in pure Kr and Xe gases over the wide E/N range from 0.001 to 500[Td] at 1[Torr] by two-tenn approximation of the Boltzmann equation.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.2
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• pp.65-69
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• 2004

This paper calculates and gives the analysis of electron swarm transport coefficients as described electric conductive characteristics of pure Ar, pure $SiH_4$, Ar-$SiH_4$ mixture gases($SiH_4$-0.5%, 2.5%, 5%) over the range of E/N = 0.01~300[Td], P = 0.1, 1, 5.0 [Torr] by Monte Carlo the backward prolongation method of the Boltzmann equation using computer simulation without using expensive equipment. The results have been obtained by using the electron collision cross sections by TOF, PT, SST sampling, compared with the experimental data determined by the other author. It also proved the reliability of the electron collision cross sections and shows the practical values of computer simulation. Electron swann parameters in argon were drastically changed by adding a small amount of mono-silane. The electron drift velocity in these mixtures showed unusual behaviour against E/N. It had negative slope in the medium range of E/N, yet the slope was not smooth but contained a small hump. The longitudinal diffusion coefficient also showed a corresponding feature in its dependence on E/N. A two-tenn approximation of the Boltzmann equation analysis and Monte Carlo simulation have been used to study electron transport coefficients.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.673-679
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• 2000

LNG Carriers are currently known as sole commercial means of shipping natural gas on the sea. They are designed to proven dangerous explosion for shipping a lot of gas over long distance. In this study. In this study, a scaled model chamber was made to investigate ventilation characteristics of the hood room in LNG carrier. Experimental study was performed in model using visualization equipments with laser apparatus and image intensifier CCD camera gated by an AOM controller Twelve different kinds of measuring area were selected as experimental condition. Instant simultaneous velocity vectors at whole field were measured by using 2-D PIV system which software adopts two-frame grey-level cross correlation algorithm. To look into stagnation area of hood room for LNG carrier, a three-dimensional numerical simulation with standard ${\kappa}-{\varepsilon}$ model was carried out by using PHOENICS for three kinds of Reynolds number, $6.5{\times}10^3$, $9.7{\times}10^3\;and\;1.29{\times}10^4$, based on the cavity inlet velocity and cavity height. The flow pattern showed the large scale counter-clockwise forced-vortex rotated at center area, small eddies at each corner and stagnation area located at left-back upper side of model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05c
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• pp.43-46
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• 2004

This paper describes the information for quantitative simulation of weal이y ionized plasma. We must grasp the meaning of the plasma state condition to utilize engineering application and to understand materials of plasma state. Using quantitative simulations of weakly ionized plasma, we can analyze gas characteristic. In this paper, the electron transport characteristic in $CH_4$ has been analysed over the E/N range 0.1~300[Td], at the $300[_{\circ}K]$ by the two tenn approximation Boltzmann equation method and Monte Carlo Simulation. Boltzmann equation method has also been used to predict swarm parameter using the same cross sections as input. The behavior of electron has been calculated to give swarm parameter for the electron energy distribution function has been analysed in $CH_4$ at E/N=10, 100 for a case of the equilibrium region in the mean energy. 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.

• Journal of Korea Foundry Society
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• v.19 no.5
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• pp.427-432
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• 1999

Most investment castings contain some porosities and microcavities. In this study, we investigated the elimination trends of various internal defects in IN738LC investment castings for industrial gas turbine blade by hot isostatic pressing. The results showed that cylindrical defects which are under $0.6mm{\Phi}{\times}7mm$ size are mostly eliminated and aspect ratio of defects is more sensitive factor than their cross section shape in removing these defects. Increasing hot isostatic pressure and holding time doesn't affect the elimination trend of cylindrical defects over $0.6mm{\Phi}{\times}7mm$ size because first step(plastic deformation) of HIP densification doesn't occur under these HIPping conditions.

• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.2205-2210
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• 2015

Experimental studies have been carried out to study the principle operation of the conductive type wire-mesh tomography sensor and analyse the wire-mesh tomography sensor for the liquid/gas two-phase flow interface and void fraction distribution in a process column. The measurement of the two-phase flows in the process column is based on the cross-sectional local instantaneous conductivity. The sensor consists of two planes of parallel electrode wires with 16 electrodes each and was placed orthogonally with each plane. The sensor electrode wires were made of tinned copper wire with an outer diameter of 0.91 mm which stretched over the sensor fixture. Therefore, this result in the mesh grid size with 5.53×5.53mm². The wire-mesh sensor was tested in a horizontal liquid/gas two-phase flows process column with nominal diameter of 95.6 mm and the sampling frequency of 5882.3529 Hz. The tomogram results show that the wire-mesh tomography provides significant results to represent the void fraction distribution in the process column and estimation error was found in the liquid/gas interface level

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.92-98
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• 2008

A combination of the instrumented indentation and 3D morphology measurement has been tried in order to perform a real-time property measurement of degraded materials in gas pipelines; three-dimensional indent morphologies were recorded using a reflective laser scanner after a series of insturmented indentations on three metallic specimens. Dimensions of the permanent deformation zone and contact boundary were analyzed from the cross-sectional profile over an remnant indent and used for estimating yield strength and hardness, respectively. Estimated yield strength was comparable with that from uniaxial tensile test and actual hardness implying material pile-up effects was lower than the calculated value from indentation curve by $20{\sim}30%$. It means that this 3D image analysis can explain the material pile-up effects on the contact properties. Additionally, a combined system of indentation and laser sensor was newly designed by modifying a shape of the indentation loading fixture.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.77-77
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• 2012

As interest has increased in the interaction between low-temperature plasmas and materials, the role of modeling and simulation of processing in plasma has become important in understanding the effects of charged particles and radicals in plasma applications. Thus in this presentation, we present the theoretical and experimental studies of electron impact cross section for plasma processing gas, such as plasma etching and deposition processes. Also, here the work conducted at the Data Center for Plasma Properties (DCPP) over last 7 years on the systematic synthesis and assessment of fundamental knowledge on low-energy electron interactions with plasma processing gases is briefly summarized and discussed.