• Magazine of RCR
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• v.15 no.4
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• pp.43-47
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• 2020

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.339-339
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• 2011

진공 플라즈마와 달리 개방된 공간에서 방전되는 대기압 플라즈마는 진공상태에서 수행되는 에칭, 증착 등의 복잡한 플라즈마 공정을 경제적이고 신속하게 수행할 수 있어, 최근 들어 연구가 활발히 진행 중이다. 이와 관련하여 He, Ar, $N_2$, $O_2$, Air 등의 여러 종류의 기체를 50 kHz 고전압에서 방전하여 대기 중에서 저온 플라즈마 공정이 가능한 아크젯 타입의 플라즈마 소스를 개발하였다. 개발된 플라즈마 소스에서는 입력전압, 기체유량, 노즐의 구조와 크기 등의 여러 운전변수에 따라 플라즈마의 방전특성이 변화되었다. 특히 본 연구에서는 아크젯의 플라즈마 발생부의 물질성분(SUS, Aluminum, Cupper)에 따른 플라즈마의 기체온도 및 전자여기 온도의 변화를 광방출분광법(OES)를 이용한 Synthetic spectrum method와 Boltzmann plot method을 통해 살펴보았다. 전압-전류 특성곡선, 시간분해 이미지 촬영법, 기체온도 측정법 등을 이용하여 발생된 플라즈마의 물리적인 특성을 분석하였다. 특히 물질의 성분에 따라 발생되는 플라즈마의 기체 및 전자여기 온도가 이차 전자 방출계수 및 물질의 전도도와의 상관관계가 있는지 연구가 진행 중이다.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.12
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• pp.44-51
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• 2004

In a micro-EDM, it is well known that an RC circuit is suitable as a discharge circuit because of its low pulse width and relatively high peak current. To increase machining speed without changing unit discharge energy, charge resistance should be decreased. But, when the resistance is very low, continuous (or normal) arc discharge occurs, electrode wear increases and machining speed is reduced remarkably. In this paper, an RC circuit with transistors is used in a micro-EDM. Experimental results show that the RC circuit with transistors can cut off a continuous (o. normal) arc discharge effectively if the duty factor and switching period of the transistor are set up optimally. Through experiments with varying charge resistances, it is shown that the RC circuit with transistors has about two times faster machining speed than that of an RC circuit.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.564-571
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• 1995

This paper deals with the arc discharge characteristics of kerosene oil as a basic study on electrical discharge machine. Using needle electrode the discharge voltage, discharge current, discharge energy and the shape of discharge crater are measured. In consequence, it becomes clear that the discharge crater(depth, height, diameter) is depending on the discharge energy. Rapid increase in depth, height and diameter of discharge crater was observed during initial discharge, where discharge energy is large. However, rather slow decrease of those values was found when discharge energy is low or N is more than 3. As the ratio of $I_p$$T_on$ increase, the shape of discharge crater gets near circle. The protuberances of the discharge crater were not formed by the melted needle electrode but by the that of work piece.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.75-81
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• 2008

Water treatment study employing plasma is thoroughly examined in the following paper. The research using water plasma torch showed superior results in terms of economical and energy efficiency due to the substantial reduction of electric power. A comparison of streamer and arc discharge phenomena taken place in water was put under close scrutiny. Dyeing wastewater exposed to the plasma treatment was sampled and analyzed for relative dissolved ozone concentration, hydrogen peroxide, as well as the color removal efficiency. It was found that streamer discharges is more effective than arc discharge in growth of $H_2O_2$ and $O_3$ by plasma chemical constituents, though plasma torch had small oxidation reagents selectivity. Thus, streamer discharges, due to the efficient plasma-chemical reactions environment, proved to be more efficient compare to the thermal arc plasma loading.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.201-207
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• 2010

In this study, we calculated arc discharges happened in high-voltage circuit breakers for understanding the complex physics and the probability of thermal breakdown. The four main parts of arc model for this virtual-reality are radiation, PTFE abaltion, Cu evaporation and turbulence. Among these important parts the turbulence model can be critical to the reliability of computation results during high-current period because the plasma flow is affected by high eat energy and mass momentum. Two kinds of turbulence model, zero-equation model and two-equation model, are applied for these calculations and are compared with the measured pressure data inside a chamber.

• Journal of computational fluids engineering
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• v.15 no.3
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• pp.9-15
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• 2010

In this study, we calculated arc discharges and flow characteristics driven by arcs in a thermal puffer chamber, which is one of most outstanding high-voltage interrupters, for understanding the complex physics and the probability of thermal breakdown. The four main parts of arc model for this virtual-reality are radiation, PTFE ablation, Cu evaporation, and turbulence. Among these important parts the turbulence model can be critical to the reliability of computation results during the whole arcing history because the plasma flow is affected by high heat energy and mass momentum. Two turbulence models, the Prandtl's mixing length model and the standard $k-\varepsilon$ model, are applied for these calculations and are compared with pressure-rise inside chamber and arc voltage between the contacts as well as flow characteristics near current zero.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.120.2-120.2
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• 2014

플라즈마 토치를 이용한 시료의 가스화용융 기술에 대하여 원리, 적용 분야, 그리고 현황에 대하여 소개한다. 플라즈마 토치는 아크방전이나 고주파에 의하여 상압 조건에서 기체를 열플라즈마로 만드는 장치이며, 산업적으로 대규모의 시료를 처리할 때는 주로 아크방전을 이용한 토치가 사용된다. 최근에는 이 플라즈마 토치가 주로 폐기물의 가스화 용융에 활용되고 있는데 이는 폐기물을 고온에서 처리할 경우 친환경적인 처리가 가능하며 경우에 따라서는 발생되는 합성가스를 이용하여 고효율로 전기를 생산할 수도 있기 때문이다. 또한 플라즈마 토치는 밀폐된 로에서 소량의 가스로 고온에서 동작할 수 있기 때문에 방사성폐기물이나 플럭스 등을 친환경적으로 용융하는 것이 가능하므로 이러한 적용 분야도 증가하고 있다. 이 발표에서는 플라즈마 토치기술과 이를 이용한 가스화/응용기술의 기본적인 소개와 함께 플라즈마 가스화용융기술을 이용한 폐기물의 가스화용융기술의 세계 현황과 국내현황, 그리고 GS플라텍의 기술 현황에 대하여 소개한다. 아울러 몇가지 구체적인 실제 플랜트를 소개하고 실제 가동 데이터와 상업적 운전 결과에 대하여도 소개하고자 한다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.91-92
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• 2018

A glassy thin film was formed on the surface of the blast furnace slag. When blast furnace slag is used as an admixture of concrete, addition of alkali activators were required. However, alkali activators are not only dangerous as chemical products, but they are also difficult to use as expensive materials. Therefore, it is necessary to study the way of removal of the glassy thin film of blast furnace slag without the risk and cost increase. In this study, to solve this problem, experiment was carried out to improve the hydration reactivity by treatment the surface of blast furnace slag using arc discharge. Experimental results show that when the surface of the blast furnace slag was tratmented by arc discharge, the glassy thin film was destroyed. And the hydration reactivity was improved, the compressive strength was increased.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.210-211
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• 2006

154kV송전용 자기현수애자 오손특성을 구하기 위하여 자체 제작된 챔버 내에서 3개의 자기애자를 현수하여 누설전류파형의 변화를 관찰하였다. 154kV 송전용자기 애자의 신뢰성평가를 위하여 ESDD 레벨에 따른 누설전류 파형 및 최대값 변화양상을 단계적 승압을 통하여 파형을 계측하였다. ESBD 레벨에 따른 누설전류 파형의 최대값이 아크방전의 영향이 없을 경우는 일정한 규칙으로 증가하였고, ESDD레벨이 높아지면서 아크방전의 발생은 주파수 분석을 통한 고조파성분의 변화양상을 볼 수 가 있다.