• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.5
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• pp.373-377
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• 2005

In this paper the gas leakage controller in processing chamber for semiconductor manufacturing is proposed. A pressure sensor is connected between the final valve and the numeric valve. A pressure sensor signal and a numeric valve signal are controlled by a proposed digital circuit module. Gas leakage condition, producing by 2nd plasticity in semiconductor process, display at LED. The proposed controller module is useful for monitoring the gas flow for preventing the critical process gas leakage.

• Journal of Energy Engineering
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• v.25 no.2
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• pp.29-36
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• 2016

In this study, diesel/natural gas dual-fuel engine was studied numerically using DoE method. The engine is CI engine for power generation and modelled by 1-D simulation GT-power. The combustion and emission characteristics were analyzed as a function of IVO, IVC and the ratio of natural gas to total fuel enegy. As the proportion of natural gas increases, the BSFC(Brake specific fuel consumption) is increased and BSNOx(Brake specific NOx) is decreased. If specific valve timing to improve the BSFC is applied to the engine, the BSFC is decreased by 1% and simultaneously BSNOx is decreased by 36%.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.44-59
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• 2020

This study analyzed a gas explosion accident. A gas smell from a underground coffee shop in the two-story building was reported to 119. A fire brigade was turned out, turned off the main valve of LPG gas cylinder on the roof, and checked the turning off of middle valve in the coffee shop. The fire brigade required a gas supplier and gas installer who arrived at the spot to take safety actions. Gas explosion occurred seven minutes after the fire brigade was withdrawn and two people died and 21 people were injured. A court decided that because the causes for gas explosion were not found, compensation responsibility could not be charged with the gas supplier, the gas installer, or Korea Gas Safety Corporation. In this reason, the court judged that only the fire brigade who was withdrawn without taking safety actions shall compensate victims or bereaved families. Therefore, fire brigades who turn out after a 119 report of a gas leak should take safety actions such as escaping people or preventing people's access and ventilating and be withdrawn when there is no possibility of fire or explosion.

• Transactions of the Korean hydrogen and new energy society
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• v.19 no.6
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• pp.474-481
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• 2008

수소 기관에서 역화없이 고성능과 저$NO_x$를 실현시키기 위하여 밸브 타이밍 변화에 따른 흡기관 분사식 수소 기관의 성능을 파악하고 가솔린의 경우와 비교하였다. 그 결과 흡기밸브 타이밍은 역화억제와 성능향상에 큰 영향을 미치는 것을 확인하였다. 흡기밸브타이밍의 진각은 역화를 억제하며 효율과 출력을 동시에 향상된다. 비록 흡기밸브 타이밍 변화에 의해 NOx는 증가하지만, 희박영역인 출 ${\Phi}=0.5$에서 현저히 감소된다. 또한 열효율은 ${\Phi}=0.5$ 토크는 ${\Phi}=1.0$에서 가장 높게 나타난다. 흡기밸브 타이밍을 $ATDC20^{\circ}$에서 TDC로 변화시켰을 때, ${\Phi}=1.0$에서 토크는 약 28% 증가되고, ${\Phi}=0.5$에서 효율은 약 7%향상된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.200-204
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• 2014

LPG is used in the home would have to depend on the provider, because there is no method for measuring the capacitance. In addition, by measuring the gas capacities can not be known because of the LPG gas replacement time and requires an alarm for replacement. In this study, and that the gas capacities to the trusted user and the supplier, in order to know when it is time to change to LPG gas by applying a Hall effect sensor developed a gas capacities measurement the valve system.

• The Journal of the Acoustical Society of Korea
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• v.40 no.1
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• pp.55-63
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• 2021

In this study, a numerical methodology is proposed for evaluating valve flow noise in a pipe conveying high pressure gas, and the effects of perforated plates on reduction of such valve flow noise are quantitatively analyzed. First, high-accurate unsteady compressible Large Eddy Simulation techniques are utilized to predict flow and flow noise by a valve in a high-pressure pipe. The validity of the numerical result is confirmed by comparing the predicted wall pressure spectrum with the measured one. Next, the acoustic power of downstream-propagating acoustic waves due to the valve flow is analyzed using an acoustic power formula for acoustic waves propagating on mean flow in a pipe. Based on the analysis results, perforated plates are designed and installed downstream of the valve to suppress the valve flow noise and the acoustic power of downstream-going acoustic waves is predicted by using the same numerical procedure. The reduction by 9.5 dB is confirmed by comparing the predicted result with that of the existing system. Based on these results, the current numerical methodology is expected to be used to reduce valve flow noise in an existing system as well as in a design stage.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.1-6
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• 2007

This paper provides the effects on the leakage characteristics of the surface roughness of a valve stem in LPG automotive. The valve stem seal is to stop an oil leakage through a sealing gap between a valve stem and a valve stem seal. The sealing performance of two components is related to a leak safety and a long life of a valve stem and a valve stem seal. The experimental results show that the optimal surface roughness of a valve stem is to recommend as $0.4{\sim}0.5{\mu}m$ in a centerline average roughness, Ra and a uniformly distributed profile of the roughness. Basically the smooth surface and uniform profiles of the roughness may reduce an oil leakage between a valve stem and a valve stem seal.

• 한국가스학회:학술대회논문집
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• 2003.05a
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• pp.127-131
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• 2003

• 월간 기계설비
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• s.297
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• pp.117-117
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• 2015

• 월간 기계설비
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• s.313
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• pp.48-49
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• 2016