• 한국입자에어로졸학회지
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• 제19권3호
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• pp.89-100
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• 2023

In our previous study, a wire-plate type electrostatic precipitator (ESP) was developed to collect bioaerosols of 100 nm size. In the study, various flow rates (40 ~ 100 L/min) and applied voltages (3 ~ 10 kV) were tested for experiment. In this study, numerical analysis was performed for the ESP of the previous study with the same flow rates and applied voltages, but with varying the size of bioaerosols to 0.04 ~ 2.5 ㎛. Overall, the numerical analysis results well predicted the experimental data. Bioaerosols of 0.1 ~ 0.5 ㎛ showed the minimum collection efficiency for all conditions because of low charge number. The effect of the ionic wind generated by the corona discharge was calculated. However, the ionic wind did not affect much the collection efficiency. The aerosol collection in the ESP of this study was due to the electrostatic force generated by particle charge in the electric field. This numerical study on the ESP can be used for the design and optimization of higher flow rate (> 100 L/min) ESP.

• 한국산학기술학회논문지
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• 제19권1호
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• pp.603-608
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• 2018

전압 인가식 제전방식이 반도체나 디스플레이 산업에는 가장 많이 사용되고 있지만, 방전에 의한 주변 미세 먼지의 흡착 및 전극핀의 오염으로 불량 발생의 원인을 제공하므로, 주기적인 관리 비용이 발생하게 된다. 전극핀의 오염 문제는 코로나 방전으로 인하여, 주변 공기의 미세한 입자를 축적함으로 생성된다. Fuzz ball의 생성은 전극핀의 마모를 촉진 시키고, 또한 정전기 제거 장치의 성능을 저하시킨다. 오염물 제거 방법은 수동 브러쉬 및 자동 브러쉬를 이용하여 기계적인 세척 방법이 효과적이지만, 추가적인 기계부품이나 사용자의 관리를 요구한다. 일부의 경우에는 이미터에 축척된 오염물이 웨이퍼나 제품에 전이될 수도 있다. 이러한 문제를 해결하기 위해, 제전기의 외부로 돌출되는 전극핀을 없애고, 이온탱크 내부에 위치한 텡스텐 전극선을 이용하여 주위 기체 분자를 직접 이온화할 수 있는 청정 환경에 적합한 정전기 제거 장치를 개발하였다. 한국기계연구원에서 시험인증한 결과, 오염 입자는 평균 $0.7572particles/ft^3$이고, 제전 시간은 2초 이하 이며, 잔류 전위는 7.6V로 만족할 만한 결과를 얻었다.

• 한국수소및신에너지학회논문집
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• 제9권2호
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• pp.77-84
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• 1998

$H_2O/O_2$, $D_2O/H_2O$, $D_2O/H_$2 등의 반응계의 수소동위원소 교환반응용 전기방전을 이용하여 용이하게 일으킬 수 있다. 예를 들어, DC 코로나 방전을 위의 반응혼합물을 통하여 일으키면 여기된 상태의 반응물이 존재하는 플라즈마를 형성하게 된다. 이러한 플라즈마 내에서 반응물들은 양자에너지 준위의 여기, 이온화 그리고 라디칼 형성등을 통하여 매우 큰 반응성을 갖게되므로 실온에서도 용이하게 수소동위원소 교환반응을 일으킨다. 본 연구에서는 $H_2/D_2O$계의 기상에서의 교환반응에 대한 연구를 실시하였다. 위 반응계는 전기방전하에서 수소(H)와 중수소(D)간의 교환반응에 의하여 HDO와 HD를 생성하게 된다. 이러한 반응생성물을 FTIR 분광법을 이용하여 시간의 함수로 측정을 하였다.

• 대한기계학회논문집B
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• 제27권10호
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• pp.1498-1507
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• 2003

A SMPS(scanning mobility particle sizer) system measures the number size distribution of particles using electrical mobility detection technique. An aerosol charge neutralizer, which is a component of the SMPS, is a bipolar charger using a radioactive source to apply an equilibrium charge distribution to aerosols of unknown charge distribution. However, the performance of aerosol charge neutralizers is not well known, especially for highly charged particles. In this study, the effect of the particle charging characteristics of two aerosol charge neutralizers on the measurement using a SMPS system was experimentally investigated for highly charged polydisperse particles. One has radioactive source of $^{85}$ Kr (beta source, 2 mCi) and the other has $^{210}$ Po (alpha source, 0.5 mCi). The air flow rate passing through each aerosol charge neutralizer was changed from 0.3 to 3.0 L/min. The results show that the non-equilibrium character in particle charge distribution appears as the air flow rate increases although the particle number concentration is relatively low in the range of 1.5∼2x10$^{6}$ particles/㎤. The low neutralizing efficiency of the $^{85}$ Kr aerosol charge neutralizer for highly charged particles can cause to bring an artifact in the measurement using a SMPS system. However, the performance of the $^{210}$ Po aerosol charge neutralizer is insensitive to the air flow rate.

• 대한기계학회논문집B
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• 제27권10호
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• pp.1489-1497
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• 2003

Aerosol charge neutralizers with various radioactive sources have been used to apply an equilibrium charge distribution to aerosols of unknown charge distribution. However, the performance of aerosol charge neutralizers is not well known, especially for highly charged particles. Measurements of highly charged particles are needed in air cleaning devices, e.g. electrostatic precipitator, bag filter with a pre-charger, and electrical cyclone. In this study, the particle charging characteristics of two different aerosol charge neutralizers were experimentally investigated for singly charged monodisperse particles and highly charged polydisperse particles. One has radioactive source of $^{85}$ Kr (beta source, 2 mCi) and the other has $^{210}$ Po (alpha source, 0,5 mCi). The air flow rate passing through each aerosol charge neutralizer was changed from 0.2 to 2.5 L/min. The results show that the charge distribution of singly charged monodisperse particles passing through the $^{85}$ Kr aerosol charge neutralizer is well agreed with the Boltzmann equilibrium charge distribution at an air flow rate of 0.3 L/min, However, it deviates from the equilibrium charge distribution when the air flow rates are 0.6, 1,0, and 1,5 L/min, On the other hands, the effect of air flow rate is insignificant for the $^{210}$ Po aerosol charge neutralizer. The non-equilibrium character in charge distribution of highly charged polydisperse particles passing through the $^{85}$ Kr aerosol charge neutralizer greatly depends on the air flow rate, however it is insensitive to the air flow rate for the $^{210}$ Po aerosol charge neutralizer.

• 전기학회논문지P
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• 제60권3호
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• pp.114-119
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• 2011

Large Power transformer is a complex and critical component of power plant and consists of cellulosic paper, insulation oil, core, coil etc. Insulation materials of transformer and related equipment break down to liberate dissolved gas due to corona, partial discharge, pyrolysis or thermal decomposition. The dissolved gas kinds can be related to the type of electrical faults, and the rate of gas generation can indicate the severity of the fault. The identities of gases being generated are using very useful to decide the condition of transformation status. Therefore dissolved gas analysis is one of the best condition monitoring methods for power transformer. Also, on-line multi-gas analyzer has been developed and installed to monitor the condition of critical transformers. Rogers method, IEC method, key gas method and Duval Triangle method are used to failure diagnosis typically, and those methods are using the ratio or kinds of dissolved gas to evaluate the condition of transformer. This paper analyzes the reliability of transformer diagnostic methods considering actual dissolved gas concentration. Fault diagnosis is performed based on the dissolved gas of five transformers which experienced various fault respectively in the field, and the diagnosis result is compared with the actual off-line fault analysis. In this comparison result, Diagnostic methods using dissolved gas ratio like Rogers method, IEC method are sometimes fall outside the ratio code and no diagnosis but Duval triangle method and Key gas method is correct comparatively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1780-1782
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• 2001

In this experiment, an attempt to use the sludge pellets as catalyst for NO removal from simulated gas is experimentally investigated by using $BaTiO_3$-sludge packed-bed reactor of plate-plate geometry. An experimental investigation has been conducted for NO concentration of 50[ppm] balanced with air, a gas flow rate of 5[1/min]. $BaTiO_3$ pellets are filled at upstream of reactor for corona discharge and sludge pellets are put at downstream of reactor for catalystic effect. The volume rate of sludge pellets to $BaTiO_3$ pellets is 50[%] and AC voltage to dischare the gases was supplied. In the result, when sludge pellets is seperated to $BaTiO_3$ by other reactor and AC voltage is supplied to $BaTiO_3$ and sludge pellets NO, $NO_2$ removal rate is higher. When gas temperature increase from room temperature to 100[$^{\circ}C$], NO removal is decreased while $NO_2$ concentration is independent on gas temperature. This result suggest that the removal mechanism of active oxyzen species and $NO_2$ in sludge is not absorption, but chemical reaction. Temperature of heating treatment is on sludge pellets increased, $NO_x$ removal rate is decrease. It is thought that organic compound is removed by heating treatment.

• 전자공학회논문지
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• 제51권6호
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• pp.244-251
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• 2014

본 논문에서, 가스절연개폐장치(GIS)의 정상상태와 비정상상태에 대해 예방진단기술을 이용하여 자세하게 서술하였다. 이 기술은 지능형 GIS 감시시스템에 의해 저장된 GIS의 데이터의 분석과 진단에 근거한다. GIS음의 파형은 방전과 자체내의 코로나 방전음에 의해 발생되는 것으로 잡음과 비슷하다. 그러므로, 본 논문에서, GIS음의 정상 상태와 비정상 상태로 분류하는데, 정상과 비정상 상태를 레벨교차율(LCR)과 스펙트로그램 에너지비율로 이용하여 구분하였다.

• 설비공학논문집
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• 제6권3호
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• pp.237-246
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• 1994

Experimental data are reported for charging and collection of NaCl aerosols in the 0.03- to $0.2{\mu}m$-geometric-mean-diameter range in 2-stage parallel-plate electrostatic precipitators. The NaCl aerosols are generated with geometric standard deviation of about 1.74 and particle generation rate of about 10^9 particles/see by the constant output atomizer and injected into the air flow in the clean wind-tunnel. The 2-stage parallel-plate electrostatic precipitator installed in the test section of the wind-tunnel is operated with a positive corona discharge. The NaCl aerosols in the channel flow are sampled and transported to the aerosol particle number concentration measurement system by using the isoaxial sampling and transport system constructed based on the Okazaki and Willeke design. The aerosol particle number concentration measurement system measures the size distribution of submicrometer aerosols by an electrical mobility detection technique. It is confirmed from comparing the measured collection efficiencies in this study and the predicted ones by our previous theoretical analysis that the predicted collection efficiencies agree well with the experimental ones. It is also found from the comparison that below about $0.02{\mu}m$ all particles are not charged and the uncharged particles are not collected, and consequently 2-stage parallel-plate electrostatic precipitators are not suitable for that particle size range.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.27-33
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• 2004

우리가 생활하는 거의 모든 곳에서 발생하는 슬러지(sludge)는 악취, 토양오염 등 많은 문제점을 가지고 있으며, 대부분의 폐기물은 매립 또는 소각에 의해 처리되고 있으나 슬러지의 경우 두 가지 방법 모두 심각한 문제점을 가지고 있어, 대체 처리방법의 개발이 시급한 실정이다. 본 연구에서는 그 슬러지를 NOx제거용 촉매 펠렛(Pellet)재료로 재활용하기 위한 가능성을 타진하기 위하여 수돗물 정수장에서 발생되는 슬러지로 펠렛을 제작하여 $BaTiO_3$ 펠렛과 하이브리드 구조로 NOx제거용 플라즈마 반응기를 제작하였고, specific energy, 전압인가 방법, 슬러지의 양, 산소농도 변화에 따른 NOx제거 특성을 측정하고 슬러지 펠렛의 영향을 측정하고 분석하였다.