• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.9
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• pp.816-820
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• 2007

We measured the electron drift velocity, W, in 0.5% $SF_6-Ar$ mixture over the E/N range from 30 Td to 300 Td and gas pressure range from 0.1 to 0.5 Torr by the double shutter drift tube with a variable drift distance, and calculated over the same E/N and gas pressure range by using the two-term approximation of the Boltzmann equation. The measured and calculated values at different gas pressure at each E/N was appreciable dependence in the results on the gas pressure.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.86-92
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• 2013

In studies on an alternative insulating gas of $SF_6$ gas, the section of the alternative gas and an insulation technique to improve its low dielectric strength have been reported, but very few attempts have been made at the dependence of a gas pressure and a gap as well as the medium effect in the alternative gas. The purpose of this paper is to analyze the dependence of the gas pressure and the gap at surface flashover voltage in dry air. The dependence is analyzed based on the medium effect. The medium effect by the gas pressure and the gap can be explained by surface roughness of a solid dielectric and an electrode as well as an electric field which decreases due to the correlation between the collision ionization coefficient and the gap, respectively. In addition, an insulation technique which can fabricate a compact eco-friendly gas insulated switchgear is proposed by the results of this paper.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.7-13
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• 1997

To investigate the pressure dependence of minimum ignition energy(MIE), thermal ignition theory, concept of heat transfer, ideal gas law, and kinetic theory are discussed. Correlation equations for the MIE and pressure were obtained through a regression analysis of reported data. In the proposed methodology the predicted MIE with pressure variations agree with reported data within a few average absolute deviations(A.A.D.). Therefore the proposed methodology has provided to be the general method for predicting the MIE of hydrocarbons.

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.214-220
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• 1990

We have studied the Infrared Multiphoton Dissociation (IRMPD) of 1-bromo-3-chloropropane by using the pulsed $CO_2$ laser. The product yields and the HCl/HBr branching ratios in IRMPD of $BrCH_2CH_2CH_2Cl$ are studied under the focused beam geometry as a function of buffer gas (He) pressure, laser energy, and photolysing wavelength. It is observed that the total dissociation yield has a laser energy dependence of 1.8-2.0 power order and the branching ratio is very slightly dependent on the pulse energy for the laser lines employed. The dependences of total dissociation yield and branching ratio on the buffer gas pressures show that the dissociation yield monotonically decreases and the branching ratio slightly decreases with the increase of the buffer gas pressure. The Energy-Grained Master Equation (EGME) was applied to explain the laser pulse energy and the buffer gas pressure(He) dependence of the dissociation yield and the branching ratio.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.248-251
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• 2002

We measured the electron drift velocity, W, in 0.5% $SF_{6}$-Ar mixture over the E/N range from 30 Td to 300 Td and gas pressure range from 0.1 to 8 Torr by the double shutter drift tube with a variable drift distance. This coefficient in the mixture was calculated over the same E/N and gas pressure range by using the two-term approximation of the Boltzmann equation. And the measured and calculated values at different gas number density at each E/N was appreciable dependence in the results on the gas number density,

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.234-234
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• 2011

Electron-neutral collision frequency is one of the important parameters in the plasma physics and in industrial plasma engineering. We can understand the momentum, energy, and charge transport properties of the plasma using electron-neutral collision frequency.[1] The wave-cutoff method is a diagnostic method for the electron density measurement, but the cutoff peak value depends on gas pressure. The wave-cutoff signal becomes unclear as increasing gas pressure. The reason of pressure dependence is that the electron-neutral collision disturbs electron motion so that microwave can propagate through plasma at plasma frequency.[2] Using the pressure dependence of wave-cutoff method we can find the electron-neutral collision frequency. At first we tried to confirm this method using well known gas such as Ar. The cutoff signal decrease as increasing gas pressure (the simulation result). The wave-cutoff signal is unclear at a gas pressure of 500 mTorr. (electron density $1.0{\times}10^{10}/cm^3$, electron temperature 1.7 eV, electron -neutral collision frequency~1 GHz). In this condition, the electron-neutral collision frequency is closed to the wave-cutoff frequency.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.787-790
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• 2009

There are several types of compressors which are appropriate for hydrogen gas station. Metal diaphragm type of hydrogen compressor is the one of them, a use in which satisfies the requirements of maintaining gas purity and producing high pressure over 700 bar. The objective of this study is to investigate an characteristics of compression as bulk modulus of oil varies. Three cases of bulk modulus ranging from $2{\times}10^9$, $4.52{\times}10^9$ and $7{\times}10^9$ were studied through FSI (Fluid Structure Interaction) analysis. Gas pressure, oil pressure and deflection degree of diaphragm were analysed during a certain period of compression process. Highest pressure and deflection were found in the condition of high bulk modulus of $7{\times}10^9$.

• 한국가스학회:학술대회논문집
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• 1999.09a
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• pp.203-208
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• 1999

• 한국가스학회:학술대회논문집
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• 1997.09a
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• pp.171-176
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• 1997

• Journal of the Semiconductor & Display Technology
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• v.8 no.4
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• pp.59-63
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• 2009

This paper presents two dimensional simulation results of an inductively coupled $Ar/O_2$ plasma reactor. The effects of operating conditions on the plasma properties and the uniformity of atomic oxygen near the wafer were systematically investigated. The plasma density had the linear dependence on the chamber pressure, the flow rate of the feed gas and the power deposited into the plasma. On the other hand, the electron temperature decreased almost linearly with the chamber pressure and the flow rate of the feed gas. The power deposited into the plasma nearly unaffected the electron temperature. The simulation results showed that the uniformity of atomic oxygen near the wafer could be improved by lowering the chamber pressure and/or the flow rate of the feed gas. However, the power deposited into the plasma had an adverse effect on the uniformity.