• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.881-882
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.157-158
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• 2011

• 대한기계학회논문집B
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• 제28권9호
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• pp.1066-1074
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• 2004

With a diode corona charger, which is a component of ELPI(Electrical Low Pressure Impactor), aerosol particles are charged to make electrical detection possible before they are collected by the impactor. We designed and evaluated two cylindrical corona chargers, each of which had a central corona needle electrode. For the performance evaluation of each corona charger the polydisperse dioctyl sebacate(DOS) particles, with diameters of 0.1∼0.8 $\mu$m and NaCl particles, smaller than 0.1$\mu$m, were used. The particles were then led through an electrostatic classifier (TSI model 3081) to classify monodisperse aerosol with minimal size deviation. After evaluating the wall loss of the particles in the corona charger, we measured the product of penetration and number of charges, Pㆍn, to evaluate the corona charger efficiency at high positive voltages of 4, 5, 6 kV.

• 조명전기설비학회논문지
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• 제23권2호
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• pp.45-52
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• 2009

본 연구는 Full-HD급 PDP의 고속 구동 구현을 위한 새로운 구동 방식에 관한 연구이다. 새로운 SPA (self-priming address) 구동 파형은 어드레스 구간에서 지속적인 프라이밍 방전을 유지하여 하전 입자 효과를 이용하여 어드레스 방전 지연 시간을 개선하기 위하여 제안되었다. 본 연구에서는 프라이밍 방전의 기본 특성에 대해 조사하였으며, 안정적인 프라이밍 방전을 유지할 수 있는 초기화 펄스 및 프라이밍 램프 펄스를 도출하였다. 특히, 프라이밍 램프 펄스의 기울기가 0.1[$V/{\mu}s$]의 미약한 프라이밍 방전의 경우에 대해서도 기존 방식의 1.2[${\mu}s$]의 어드레스 방전 지연 시간을 0.8[${\mu}s$]로 획기적으로 개선할 수 있는 것을 확인하였다.

• 대한기계학회논문집B
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• 제26권8호
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• pp.1102-1114
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• 2002

An electret filter is composed of permanently charged electret fibers and is widely used in applications requiring high collection efficiency and low-pressure drop. In this work, the collection efficiency of the filter media used in manufacturing cabin air filters was investigated by using poly-disperse particles when submicron particles were loaded. Long-term experiments were conducted by applying two different charging states, which were spray electrification and charge equilibrium by bipolar ionization. In order to investigate the effect of particle loading in filter media, NaCl particles were generated from 0.1% and 1% solutions by an atomizer. Liquid DOS particles were used to evaluate the effect of liquid particles on the collection efficiency of an electret filter. The results show significant effect of charge amount and size distribution of loading particles on the collection performance of a filter media in submicron region. Smaller particles loaded in electret fibers cause a more rapid degradation in collection efficiency and have lower minimum efficiency with time. The pressure drop of a filter media do rarely increase when the collection efficiency decreases to the minimum value. For the larger particles charged by spray electrification, which have charge amounts more than that of Boltzmann equilibrium charge distribution, the pressure drop of a filter media slowly increases in comparison with that of equilibrium charged particles. For DOS particles it is shown that the charging level of an electret filter severely decreases and the collection efficiency is below 10% in some particle size range.

• 대한기계학회논문집B
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• 제30권2호
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• pp.186-192
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• 2006

We applied a new charging system using the condensation and evaporation method to charge the submicron particles with a uniform charging performance. The monodispersed NaCl submicron particles were condensed by n-butanol vapor and grew up to micron droplets with a same size, regardless of their initial size. Those condensed droplets were charged in an indirect corona charger. The indirect corona charger consisted of the ion generation zone and the particle charging zone. In the ion generation zone, Ions were generated by corona discharge and some of them moved into the particle charging zone by a carrier gas and mixed with the condensed droplet. And finally, the charged and condensed droplets dried through an evaporator to shrink to their original size. The average charge and penetration rate of the particles before and after evaporation were measured by CPC and aerosol electrometer and compared with those of a conventional corona charger. The results showed that the average charge was $5\~7$ charges and the penetration rate was over $90\%$, regardless of the initial particle size.

• 대한기계학회논문집B
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• 제28권5호
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• pp.501-509
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• 2004

Unipolar diffusion charging of non-spherical particles was investigated for various particle shapes. We researched with TiO$_2$agglomerates produced by the thermal decomposition of titanium tetraisopropoxide (TTIP) vapor. TTIP was converted into TiO$_2$, in the furnace reactor and was subsequently introduced into the sintering furnace. Increasing the temperature in the sintering furnace, aggregates were restructured into higher fractal dimensions. The aggregates were classified according to their mobility using a differential mobility analyzer. The projection area and the mass fractal dimension of particles were measured with an image processing technique performed by using transmission electron microscope (TEM) photograph. The selected aggregates were charged by the indirect photoelectric-charger and the average number of charges per particle was measured by an aerosol electrometer and a condensation particle counter. For the particles of same mobility diameter, our results showed that the particle charge quantity decreases as the sintering temperature increases. This result is understandable because particles with lower fractal dimension have larger capacitance and geometric surface area.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1713-1717
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• 2008

We have developed a nanoparticle focusing mask which can generate particle arrays directly on the large area with high resolution. Using this mask, nanomaterials are precisely deposited onto desired positions on a substrate surface. We obtained various sizes of arrays ranging from 80 nm to 6 ${\mu}m$ with silver and copper nanoparticles that are generated by a spark discharge and an evaporation-condensation method. The feather size is much smaller than that of mask openings due to the focusing effects, like electrostatic lens, caused by charge or electric potential on insulator mask surface, which also prevent a mask clogging. The particle array size depends on the size of mask open patterns and focusing effects near the mask relate to ion flow rate and electric potential. We have demonstrated that diverse size of arrays with high resolution could be obtained repeatedly using the same sized mask in atmosphere.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.413-414
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• 2001

실내공간에 존재하는 먼지입자를 제거하는데 적용되는 대표적인 방법들로는 섬유상 필터를 이용한 먼지입자 여과 기술과 전기집진기를 이용한 여과 기술이 있다. 섬유상 필터를 이용한 여과 기술은 입자의 관성충돌(inertial impaction), 차단(interception) 및 확산(diffusion) 메카니즘을 이용한 기술로써, 입자포집 효율이 아주 우수한 반면 압력손실이 큰 단점이 있다. 이러한 단점을 개선하기 위하여 개발된 필터로써 정전부착(electrostatic deposition) 메카니즘을 이용한 정전여과필터(electret filter)라고 것이 있는데, 이것은 섬유 자체에 정전 하전을 주입시킨 특수한 필터이다. (중략)

• 한국정보과학회논문지:소프트웨어및응용
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• 제32권8호
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• pp.769-780
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• 2005

본 논문에서는 스프링-댐퍼 메쉬를 2차원 영상 패턴의 변형을 모델링 및 분석하는 데 응용하는 방법을 제안한다. 기존의 메쉬와 다르게 새롭게 제안된 메쉬 모형은 메쉬 노드와 영상 픽셀을 하전입자로 표현하고 둘 사이의 상호작용에 의하여 변형되는 메쉬를 다양한 기준함수에 의하여 분석하는 것이다. 메쉬의 변형 과정은 하전입자 사이의 상호작용에 의한 스트레스 완화 과정으로써 널리 알려진 간단한 수치적분법을 사용한다. 변형 메쉬평가함수로 네 가지를 제안하고 각각의 성능을 분석하였다. 훈련 메쉬로는 샘플 영상의 평균 패턴을 구하여 메쉬로 직접 변환한 것을 사용하였다. 실험 결과 각 함수는 국소 변형을 모두 제대로 평가하는 측도로서는 아직 부족하지만 앞으로 이에 대한 보완 또는 새로운 함수의 제안, 그리고 이완 과정의 개선이 뒤따른다면 보다 체계적인 분석 방법과 높은 성능을 제공할 것으로 판단된다.