• 한국전자통신학회논문지
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• 제7권6호
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• pp.1403-1411
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• 2012

본 논문에서는 최근 DC 전력케이블에서 큰 이슈가 되고 있는 공간전하(space charge) 문제와 관련하여 공간전하의 비파괴 측정법 중 하나인 펄스정전응력법(PEA method)에 대한 이론적 고찰을 수행하였으며, 이를 바탕으로 직류전압 하에서 고분자 유전체 내에서 공간전하분포를 측정할 수 있는 시스템을 개발하였다. 또한, 보정(deconvolution) 처리를 통해 왜곡된 공간전하 신호에 대한 개선을 실시함으로써 신호의 정확도를 개선하였다.

• Transactions on Electrical and Electronic Materials
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• 제7권5호
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• pp.235-239
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• 2006

Charge dynamics in polymeric materials after aged under ac electric field using the pulsed electroacoustic (PEA) technique is reported. The emphasis is placed on charge decay. The charge dynamics of the ac aged additive free low density polyethylene (LDPE) samples under dc bias differ from the sample without ac ageing, indicating changes brought in by ac ageing. It is believed that a slow decay rate of charge in the ac aged sample is related to the formation of deep traps in the material. However, chemical analysis by infrared spectroscope (FTIR) and Raman microscope reveals no significant chemical changes taken place in the bulk of the material after ac ageing. Further experiments on irradiated LDPE have revealed a similar behaviour, i.e. the charge decay is slower in irradiated samples than that of fresh sample. The findings presented clearly indicate that space charge measurement can be used as a diagnostic tool to monitor ageing in polymeric materials.

• 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.

• 한국조명전기설비학회지:조명전기설비
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• 제6권6호
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• pp.23-31
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• 1992

Charged particle in the polymers is supposed to affect the electrical conduction and to lead them th dielectrical breakdown finally. So we measured the space charge distribution made by application of high electric field and evaluated the polarity of the charged particle affected on electrical conduction and space charge formed in the insulating materials by using temperature gradient thermally stimulated current measurement method(TG-TSC measurement). As a result, in the cross-linked polyethylene, A-peak was caused from dipole polarization, C-peak was caused from ionic space charge polarization and D-peak was injected trap hole. Also we found it crossible the evaluated the polarity of injected trap carrier and electron(or hole) of carrier trap in the cross-lined polyethylene. We found that ${\gamma}$-ray irradiated low density polyethylene had a relation to the electronic trap and we also could get the value of electric field distribution in the samples of which evaluation was available.

• 한국군사과학기술학회지
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• 제19권3호
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• pp.339-345
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• 2016

This paper is concerned with the numerical simulation result of pressure propagation to the main charge by warhead penetration into concrete targets. In this study, we developed on-line pressure measurement method in the main charge during warhead penetration. Using the on-line pressure measurement method, we successfully recorded the pressure-time history in the main charge during the field penetration test. Then we compared result of numerical simulations with test data and found that the simulation results are in good agreement with the test results. Finally, through the numerical calculations it is concluded that the installation of liner is effective in reducing pressure level produced in the main charge.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.433-436
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• 1999

In this paper we applied TVS(Triangular Voltage Sweep) method to calculate the mobile ionic charge densities in some ferroelectric thin films. During the measurement, the temperature of specimens were maintained at 20$0^{\circ}C$. By this method, the amount of mobile ionic charge Q$_{m}$ and mobile ionic charge density N$_{m}$ of a MFIS structure were calculated 3.5 [pC] and about 4.3$\times$10$^{11}$ [ions/cm$^2$], respectively. In order to successful TVS measurement, the gate leakage current density of films must be low 10$^{-9}$ (A/cm$^2$) order.der.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2011년도 한국우주과학회보 제20권1호
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• pp.20.2-20.2
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• 2011

The NASA Antarctica balloon experiment CREAM has successfully collected the data of energetic cosmic rays during flights in past years. We will present the recent analysis results of the CREAM experiment. We will also report on the launch and recovery process of the latest flight. The silicon charge detector of the CREAM has played the key role in the precision measurement of the charge constitution of energetic cosmic rays. We proposed the upgrade of the CREAM experiment with the installment of a new large silicon charge detector on top of the CREAM instrument. The charge measurement of the large silicon detector with no material in front is expected to improve the accuracy of the CREAM charge measurement drastically when combined with the measurement of the existing double layer silicon detector. We will present the fabrication of the large silicon detector and its performance in the radiation source test as well as in the beam test.

• 한국조명전기설비학회지:조명전기설비
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• 제10권3호
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• pp.78-85
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• 1996

표면전위측정 수단을 이용하여 polyethylene terephthalate의 electret 구조를 해명하는 실험을 하였다. 시료에 전극을 증착하므로서 내부의 전하생성과 감쇠를 관측하였다. electret 의 기구에는 hetero charge 와 home charge가 공존하고 있으며 model로 2전하이론을 기반으로 연구하였는데 hetero charge는 쌍극자와 내부의 이온 변위로 되고 hetero charge를 형성하는 것은 외부에서 주입된 전하라고 생각된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.605-608
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• 2002

This paper proposes a real-time wall charge measurement circuit for three-electrode AC PDP. It includes a charge-compensation network, current-integrating capacitors, initializing switches, and an op-amp. With this equipment, we measure the wall charge variations for the effects of sustain voltage, sustain pulse width, sustain frequency, and neighboring cells.

• 펄프종이기술
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• 제29권3호
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• pp.87-94
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• 1997

As the paper market becomes more and more competitive, more mills will want to switch to alkaline papermaking to take advantage of the Vowing demand. Many papermakers have tried to do this without success in the past much like the American papermakers did in the late 1970's. The Problem is that runnability Problems occur, drainage slows, Presses pick drying becomes more difficult and sheet quality suffers as a result Sheet holes and breaks occur, and runnability becomes a real operating problem. Converting to alkaline papermaking is not as simple as turning off the alum. We must be aware of the numerous factions that alum served at acid pH and provide alkaline alternatives. It is the purpose of this paper to discuss methods of deposit control via charge neutralization and system control at alkaline pH. This article explains the concept as well as the measurement and control. The resultant benefits are seen in runnability, quality and profitability for the papermaker.