• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.725-730
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• 2008

In this study, we found out charged particle's deposition characteristic by experiments of $0.5{\mu}m$, $1.0{\mu}m$, $3.0{\mu}m$ size particle's concentration decay. We carried out the experiments on charged particle deposition onto the vertical cleanroom wall panel and some other fundamental experiments. The particle deposition mechanism is consist of sedimentation, convection, diffusion, thermophoresis, electrostatic and so on. Particle size determines mainly working deposition mechanism. The charged particle is made with corona discharge that are constituted field charging and diffusion charging. In addition, this combinational mechanism is called combined charging. The type of corona discharge determines quantity of particle electrical charge. In conclusion, we assumed that quantity of particle electrical charge accelerations deposition velocity onto the vertical cleanroom wall panel and proved it. And we figured out particle's deposition characteristic through compared between our experiment's results.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.212.2-212.2
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• 2012

지구 자기권에 존재하는 플라즈마 입자의 다중관측을 목적으로 개발된 초소형 탑재체 STEIN (SupraThermal Electron, Ion, Neutral) 은 경희대학교와 UC Berkeley가 공동으로 개발 중인 3대의 초소형 과학위성 TRIO-CINEMA (TRiplet Ionosphere Observatory - Cubesat for Ion, Neutral, Electron and MAgnetic fields) 에 탑재될 입자 검출기이다. 32개의 픽셀로 이루어진 STEIN 검출기는 2~300 keV의 전자, 4~300 keV의 이온과 중성입자(Energetic Neutral Atom: ENA) 를 분리 계측할 목적으로 설계되었으며, 하전입자가 정전장 편향기를 통과하여 서로 다른 검출기 픽셀에 도달함으로써 전자와 이온, 중성입자를 분리하여 계측할 수 있도록 하였다. 한편, STEIN 구조물에서 발생한 2차 입자의 검출을 방지하기 위해 정전 편향기 사이에 차단날(blade)을 설계하였다. 본 연구에서는 STEIN 모의실험 예비 결과로써 전기장에 크기 및 차단날에 의한 하전입자의 궤적과 이에 따른 분리 계측 성능을 알아보고자 Geant4 (GEometry ANd Tracking)를 사용하여 검출기 픽셀에 입사하는 전자의 초기 위치를 분석하였다. 전자의 입사 위치는 검출기로부터 5 cm 전방에서 6 mm * 20 mm 범위 내에서 무작위로 생성하여 검출기의 방향으로 수직 입사하였다. 분석 결과 전자들은 전기장의 방향에 따라 편향되는 결과를 보였으며, 저에너지 전자는 강한 전기장의 영향으로 차단날에 의해 차폐되어 검출되지 않았다. 따라서 전기장의 크기와 차단날에 따른 입자 분리 검출이 가능함을 본 모의실험을 통해 확인하였으며, STEIN 운용 시 입자 분리 검출 및 결과 분석 기반으로 본 연구 결과를 사용될 수 있을 것으로 기대된다.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.85-90
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• 2001

This work presents experimental results of filter media test by using particles from $0.02\;to\;0.6{\mu}m$ in diameter and by applying different charging states. In order to investigate the electret filter performance, the collection efficiency and the pressure drop of filter were measured. The face velocities of test filters varied from 2.4 to 20.4 cm/s. Another experiment setup for the cartridge cabin air filter was used to get an collection efficiency in submicron region. After charging level of electret filter severely decreased, the change of collection efficiency was verified. Experimental results show that the reliability of electret filters can be poor in some conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.46-53
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• 2003

Effects of electric force on the morphology and growth of aggregates were studied experimentally. Nano-sized NaCl particles were supplied to a flame to perform the unipolar charging state. This electric precursor did not modify a temperature profile of the flame. The morphology of aggregates was measured by TEM image processing technique and the light scattering technique. In the unipolar charged state, the fractal dimension of aggregates was smaller than that of' the electrically neutral state. This result was in good agreement with our previous numerical simulations.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.2
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• pp.185-191
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• 1992

In this paper, it is attempted to distinguish the charged particles and to judge the polarity by the use of Thermally Stimulated Current(TSC) and Temperature Gradient Thermally Stimulated Surface Potential Measurement(TG-TSSP)with experimental insulation material XLPE-EVA for power cables which is made by blending cross-linked polyethylene(XLPE) and ethylene-vinylacetate copolymer(EVA). In addition, it is performed to investigate the effect of EVA blending. From the experimental results, it is known that for the case of XLPE-EVA blended experimental material, the generation of space charged electric field is not obtained in the high temperature region due to the obatruction of the injection of trapping carrier by the electron and the positive hole.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.4
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• pp.289-294
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• 2001

A well defined electro-spraying and electro-static precipitator(ESP) experiment is carried out to investigate the charging characteristics of the submicron particles and the monodisperse particles. The basic idea is that the highly charged electro-sprayed droplets will be produced into the gas when the Coulombic repulsive force on the surface is higher than the surface tension of the spraying liquid. During this process many highly charged smaller droplets or ions, if the droplets are completely dried out, will be produced in the space. These charged species will be attached ion the particles and then eventually charge the particles. These charged particles will be easily collected with ESP. The experimental results show that the atomizer generated particles with geometric mean diameter (GMD) of 62nm are charged more than 90% even at the mean face velocity of 2.5m/s at the charging zone.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.6
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• pp.677-684
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• 2003

A new unipolar aerosol charger was developed by using an indirect photoelectric charging. The charger consists of two coaxial tubes, the inner UV lamp wrapped with stainless mesh and the outer Al cylinder. In this study, the effects of flow rate, particle size, and electric field were examined to search the optimal charging conditions with experimental and numerical methods. Monodisperse NaCl particles were fed into an annular space and the particles were charged by negative ions generated from Al plate exposed to the UV light. According to experimental results, the average number of elementary charge on particles increases from 2.5 to 5.5 as particle size increases from 50nm to 130nm at 2.5 L/min and 100V. The average number of elementary charge on particles was maximized at 25V as the electric potential between the stainless mesh and Al plate was varied from 0V to 400V.

• Journal of the Semiconductor & Display Technology
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• v.1 no.1
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• pp.35-40
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• 2002

Understanding of charging properties of a small particle is necessary to control the particle contamination and to improve productivity of the electronic device in the plasma aided semiconductor manufacturing processes. In this study, the effects of both magnetic field and particle size on the charging properties are experimentally investigated in collisional dusty plasmas. The experiments carried out in the system consisted of a monodisperse particle generation system, a DC magnetized plasma generation system and a charge measurement system. The plasma chamber is made of cross-shape Pyrex surrounded by magnetic bucket (composed of 12 permanent magnetic bar) to confine the plasma. DC magnetic field up to 250G are applied to the plasma zone by external magnetic coil. Previous work shows the charging effect clearly increase with increasing the size of the particle and plasma density, as it was expected.

• Journal of Radiation Protection and Research
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• v.10 no.2
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• pp.89-95
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• 1985

An alternative estimator for dose equivalent was derived. The original LET distribution concept was transformed into a charged particle fluence spectrum concept along with the definition of an average quality factor named slowing-down averaged quality factor by adopting the continuous slowing down approximation. With the alternative estimator, the dose equivalent delivered into a receptor located in a given radiation field can be directly and conveniently estimated in a Monte Carlo procedure. The slowing-down averaged quality factors for the energy range below 10 MeV were evaluated and tabulated for the charged particles which may be generated from the interactions of neutron with the nuclei composing soft tissue.

• Electrical & Electronic Materials
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• v.5 no.2
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• pp.166-174
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• 1992

본 논문에서는 열자격 전류 기법을 이용하여 폴리비닐덴 후로라이드필름에 대한 하전 입자의 거동 상황을 살펴보았는데 결과로 .betha.2, .betha.1, .alpha. 그리고 .alpha.'의 4개의 피크가 -35[.deg.C], -10[.deg.C], 60[.deg.C], 그리고 85[.deg.C]부근의 온도에서 관측되었다. 처음 .betha.2 피크와 .betha.1 피크에서의 온도는 항상 일정하였고 .alpha. 피크와 .alpha.'피크는 형성온도에 의존하였다. .betha.2 피크와 .betha.1 피크의 기원은 쌍극자의 기여로 .alpha. 피크는 결정질 영역의 얕게 트랩된 하전 입자의 탈트랩으로 그리고 .alpha.'피크는 형성온도에 따라 발생되는 Langmurian Model과 Henry Model에 의하여 나타났다. 이러한 해석을 위해 분리된 단일 완화곡선에 점근해법에 의한 수치해석 기법을 적용함으로서 사용시료의 제정수에 대한 계산을 보다 정확하게 구할수 있었으며 특히 적분항에 대한 계산오차가 감소함을 확인하였다.