• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.169-171
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• 1993

In order to estimate space charging process in the corona charging apparatus which has been used to make polymer electret cell, the electrical properties of 30[${\mu}m$] thick polypropylene film were obtained from TSC measurement after corona charging between copper knife electrode and aluminum cylinder electrode with the voltage of -8, -7, -6, -5 (kV). And, the electrostatic contour and the electric field vector were calculated using Finite Element Method with the electrical properties obtained from TSC spectra analysis. The edge effect around the edge of knife electrode affects electrostatic contour on the surface of specimen and the electric field concentration inside the polymer. As a result the uneven charging state in the electret cell due to the mistake of design was calculated, and the optimal design of corona charging apparatus opprobriate to various specimen was come to be practicable.

• 전기의세계
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• v.29 no.10
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• pp.615-620
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• 1980

본고의 내용은 다음과 같다. 1. 일렉트렉트의 정의 2. 일렉트렉트의 분류 3. 일렉트렉트의 생성기구 개요 4. 일렉트렉트의 열분석 5. 일렉트렉트의 응용

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.26 no.1
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• pp.18-22
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• 1997

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.3
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• pp.259-268
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• 2001

In this study, we have developed a simulation method to predict the initial collection efficiency of a unipolar charged fiber in the electret filters. The particle sizes considered were in the submicron range and thus Brownian motion of particles was also taken into consideration along with electrostatic forces acting on the particles. The simulation results were compared with other investigators experimental data on single fiber efficiency as well as with the calculated results using the existing correlations on single fiber efficiency. It has been shown that simulation results are in good agreement both with the experimental data with those predicted by the correlations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1989.06a
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• pp.114-117
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• 1989

An infrasonic wide band transducer fabricated by polytetrafluoroethylene(PTFE)is studied experimentally. The sensitivity of the transducer depends largely on the surface charge of the Electret and is typically between-50 and -62[dBV] for a sound-pressure level of 1[ubar]. The sensitivity of the transducer does not decay over periods of the order of years at room temperature. The frequency response is within 1.5[dB] from 1 to 6,000[Hz] and within 12[dB] from 0.05[Hz] to 1[Hz] respectively. The resonance frequency of the element is 510 [Hz]. We conjectures that the element is applicable to accustics, communication system, seismological observation and other similar filed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.4
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• pp.417-426
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• 1994

Filter media performance was evaluated using monodisperse NaCl particles with Differential Mobility Analyzer and Ultrafine Condensation Particle Counter. Low or medium performance filters show that the most penetrating particles size(MPPS) is around $0.3{\mu}m$ in diameter and is shifted to smaller sizes as the filter face velocity increases. However, HEPA and ULPA filters show MPPS is around $0.15{\mu}m$ in diameter and is also shifted to $0.1{\mu}m$ in diameter as the face velocity increases. In case of electret filter, the MPPS is found around $0.04{\mu}m$ region for Boltzmann charge equilibrium particles. There is a tendency of strong collection efficiency decrease for large particles as the face velocity increases on the contrary to the other filters. One of the medium performance filter efficiency was compared with filtration theory and the good agreetment was found in the experimental range.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.5
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• pp.489-495
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• 1991

In this paper, we study the electrical conduction mechanism in Langmuir-Blodgett(LB) ultra thin films for which the LB device has a metal/LB films(TCNQ)/metal sandwich structure. Our experiments show that the current at the LB device does not depend on the temperature at below 0 C. This phenomena confirm that the electrical conduction current is a tunnel current inherent to ultra thin films. However, the current depends upon the temperature near the room temperature. This phenomena indicates the electeical conduction current is a Schottky current inherent to ultra thin films.

• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.10-12
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• 2007

See Full Text

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.198-200
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• 1985

• Proceedings of the KIEE Conference
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• 1983.07a
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• pp.201-202
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• 1983