• 전력전자학회논문지
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• 제9권4호
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• pp.350-355
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• 2004

본 논문에서는 열원인 전력용 반도체 소자와 방열판 및 팬으로 구성된 강제 냉각방식 방열 시스템을 먼저 해석 가능한 요소로 나눈 후 각 요소에 대한 해석적이거나 실험적인 설계 식을 제시하고 이를 적용한 설계 방법을 제안하였다. 제안한 방법으로 400kW급 IGBT 인버터용 강제 냉각방식 방열 시스템을 설계하고 제작하였다. 실험결과는 설계 온도가 실험치에 대해 10［%］ 오차 범위 내에서 잘 일치함을 검증하여 제안한 해석적인 정상상태 설계방법의 타당성을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
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• pp.45-49
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• 2008

Polyethylene is widely used as the insulator for power cable. To investigate the conduction mechanism for power cable insulation under ac high field, it is very important to acquire the dissipation current under actual running field. Recently, we have developed the unique system, which make possible to observe the nonlinear dissipation current waveform. In this system, to observe the nonlinear properties with high accuracy, capacitive current component is canceled by using inverse capacitive current signal instead of using the bridge circuit for canceling it. We have already reported that the dissipation currents of $40\;{\mu}m$ thick LDPE film at 10 kV/mm and over 140 Hz, it starts to show nonlinearity and odd number's harmonics were getting large. To investigate the conduction mechanis ms in this region, especially space charge effect, various kinds of estimation, such as time variations of instantaneous resistivity for one cycle, FFT spectra of dissipation current waveforms and so on, has been examined. As the results of these estimations, it was found that the dissipation current will depend on not only the instantaneous value of electric field but also the time differential of applied electric field due to taking a balance between applied field and internal field. Furthermore, two large peaks of dissipation current for each half cycle were observed under certain condition. In this paper, to clarify the reason why it shows two peaks for each half cycle, the film thickness dependences of dissipation current waveforms were observed by using the three different thickness LDPE films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.349-350
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• 2007

Polyethylene is widely used as the insulator for power cable. To investigate the conduction mechanism for power cable insulation under ac high field, it is very important to acquire the dissipation current under actual running field. Recently, we have developed the unique system, which make possible to observe the nonlinear dissipation current waveform. In this system, to observe the nonlinear properties with high accuracy, capacitive current component is canceled by using inverse capacitive current signal instead of using the bridge circuit for canceling it. As the results of these estimations, it was found that the dissipation current will depend on not only the instantaneous value of electric field but also the time differential of applied electric field due to taking a balance between applied field and internal field. Furthermore, two large peaks of dissipation current for each half cycle were observed under certain condition. In this paper, to clarify the reason why it shows two peaks for each half cycle, the film thickness dependences of dissipation current waveforms were observed by using the three different thickness LDPE films.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1990년도 추계학술대회
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• pp.118-121
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• 1990

This paper describes development of an implantable power switching system for biotelemetry system. This system is designed and manufactured to achieve as small size and low power dissipation as possible, using pulse powered circult and CMOS technology. The function of the power switching system is to connect the implantable battery to implanted sensors and, electronics systems by receiving intermittent command signals from external circuits. The power dissipation of this system was about $15{\mu}W$ for a stand-by operation.

• 한국항행학회논문지
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• 제24권4호
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• pp.261-266
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• 2020

항공기 장착물에 KW급 전력변환장치가 탑재되는 경우, 전력 변환 시 발생하는 대량의 발열에 대한 방열설계가 고려되어야 한다. 적절한 방열을 하지 못하는 경우, 장비 오작동 및 화재의 우려가 발생하며 이는 항공기 운항에 있어 치명적인 요인이 될 수 있다. 본 논문은 항공기 장착물에 탑재되는 KW급 전력변환장치의 방열설계에 관하여 기술하였다. 전산해석을 통한 설계 및 제작 후 시험을 수행하였으며, 고전력 변환에 따른 발열부품의 급격한 발열 현상을 확인하여 해석 모델을 보정하였다. 모델 보정 후 방열구조가 개선된 형상으로 설계를 개선하였으며, 미 군사규격인 MIL-STD-810G 의 고온동작 시험을 수행하여 개선된 형상의 타당성을 검증하였다.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
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• pp.272-277
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• 1999

The necessity of voice recording device was increased using voice signal IC with designed LSI/VLSI. The control unit which developed here voice recorder has low power dissipation, portable, and comfortable using voice source. However, the Korea voice recorder abilities far behind of foreign products for its performance and size on sailing. So we used Chua circuit to improvement voice quality abilities after minimize power supply device and circuit by designing voice recording device into lower power dissipation power circuit.

• Journal of the Optical Society of Korea
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• 제16권1호
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• pp.6-12
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• 2012

We present the optical models and calculation results of thin-film organic solar cells (OSCs) at oblique incidence of light, using the transfer matrix method. The simple expression for the optical power dissipation is derived at oblique incidence for s- and p-polarized light. The spatial distribution of the electric field intensity, the optical power density, and the optical power dissipation are calculated in both s- and p-polarized light with respect to the incidence angle. We identify how the light absorption efficiency for p-polarized light becomes relatively larger than that for s-polarized light as the incidence angle increases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1572-1573
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• 2006

This paper presents electrical properties of Zinc Oxide(ZnO) surge arrester blocks under the power frequency AC voltages and various temperatures. The leakage current, $I_{R}-V$ curios and power dissipation for the fine and aged ZnO surge arrester blocks were measured as a function of the temperatures and applied voltages. When the temperature is increased from $50\;[^{\circ}C]$ to $150\;[^{\circ}C]$, the total leakage current significantly increased at the sane applied voltage level. Also, the resistive leakage currents and power dissipation were increased with increasing temperature. The leakage current and power dissipation of the aged ZnO arrester blocks were higher than the fine ZnO arrester blocks.

• Journal of Radiation Protection and Research
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• 제48권3호
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• pp.124-130
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• 2023

Background: When bipolar junction transistors (BJTs) are used as switches, their switching characteristics can be deteriorated because the recombination time of the minority carriers is long during turn-off transient. When BJTs operate as low frequency switches, the power dissipation in the on-state is large. However, when BJTs operate as high frequency switches, the power dissipation during switching transients increases rapidly. Materials and Methods: When silicon (Si) BJTs are irradiated by fast neutrons, defects occur in the Si bulk, shortening the lifetime of the minority carriers. Fast neutron irradiation mainly creates displacement damage in the Si bulk rather than a total ionization dose effect. Defects caused by fast neutron irradiation shorten the lifetime of minority carriers of BJTs. Furthermore, these defects change the switching characteristics of BJTs. Results and Discussion: In this study, experimental results on the switching characteristics of a pnp Si BJT before and after fast neutron irradiation are presented. The results show that the switching characteristics are improved by fast neutron irradiation, but power dissipation in the on-state is large when the fast neutrons are irradiated excessively. Conclusion: The switching characteristics of a pnp Si BJT were improved by fast neutron irradiation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2035_2036
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• 2009

This paper is purpose to understand the dissipation factor properties of the oil-filled large transformer according to the oil filtering. In order to know the insulation characteristic change by insulating oil filtering, we carried out the insulation diagnostic test for the same transformer before oil filtering and after. The insulation diagnosis tests are consist of the megger, the polarization index, the AC current test, the dissipation factor test and the partial discharge test, Especially we took notice of dissipation factor change, we analyzed and made a comparison of the two cases test result.