• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1748-1750
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• 2002

Partial discharge is attendant physical phenomenon on electromagnetic, sounds, lightning and mechanical vibration. In this paper, we simulated GIS and measured the radiated electromagnetic wave emitted from partial discharge in $SF_6$ gas using antenna(30[MHz] ${\sim}$ 2[GHz]) and spectrum analyzer. This paper describes characteristics of radiated electromagnetic waves with distance 1 [m] between antenna and discharge source.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.199-199
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• 2009

실리콘을 기판으로 하는 대부분의 태양전지에서는 표면반사에 의한 광 에너지 손실을 최소화 시키고자 습식에칭 (wet etching)에 의한 텍스쳐링 처리가 이루어진다. 그러나 습식 에칭은 공정 과정이 번거롭고 비용이 많이 든다. Inductively Coupled Plasma Etcher 장비를 이용한 플라즈마 에칭 (plasma etching)을 실리콘 표면에 적용하여 공정을 간단하고, 저렴하게 하며 반사도를 획기적으로 낮추는 기술을 개발되었다. 플라즈마 에칭으로 형성된 나노구조는 내부전반사를 일으키며 대부분의 태양에너지를 흡수한다. 나노구조는 필라(pillar)의 형태로 나타나며, 이는 플라즈마 에칭 시 발생하는 이온폭격과 에칭 측벽 식각 보호막 (SiOxFy : Silicon- Oxy-Fluoride)의 형성 때문이다. 최저의 반사도를 얻기 위해서 나노필라 형성에 기여하는 플라즈마 에칭 시간, RF bias power, SF6/O2 gas ratio의 변화에 따른 실험이 진행되었다. 플라즈마 발생 초기에는 표면의 거칠기만 증가할 뿐 필라가 형성되지 않지만 특정조건에서 4um 이상의 필라를 얻는다. 이 구조에 알루미늄 전극을 형성하여 전기적 특성을 관찰하였다. 플라즈마 에칭을 적용하여 제작된 태양전지는 표면의 반사도가 가시광 영역에서 약 1%에 불과하며, 마스크 없이 공정이 가능한 장점이 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.252-255
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• 1996

Cl-based gas chemistry is generally used to etching for Al alloy metallization. After the etching of Al alloy with Cl-based gas plasma, residual chlorine on Al alloy reacts with $H_2O$ due to air exposure and results in Al corrosion. In this study, the corrosion Phenomena of Al were examined with XPS(X-ray photoelectron spectroscopy) and SEF(Scanning electron microscopy). It was confirmed that chlorine mainly existed at the grain boundary of Al alloy after plasma etching of Al alloy with Cl-based gas chemistry and Al corrosion was largely generated at the grain boundary of Al a1loy. And residual chlorine was passivated by sulfur and fluorine which were generated by SF$_{6}$ plasma. These effects of passivation reduced the Al corrosion due to air exposure.e.

• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.531-533
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• 2000

In compared with air insulated switchgear, GIS has a high efficiency and confidence So the transformer substation can be reduced the size to 1/10. Insulation method using $SF_6$ gas has a very excellent insulation characteristics for high pressure equipment but has a characteristics that insulation heredity is changed for internal unequal electric field. So analysis of electromagnetic field in GIS is very important basic data for structure design and trouble diagnosis process. In compared with established method, SNM in this paper observes variation of the electromagnetic field with real time and get result very similar to measurement. In order to know the variation of electromagnetic field distribution for transient response for time and position, variations are observed when the spacer is bonded and metal particles are moving fast.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.371-372
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• 2008

In this paper, we experimentally investigated discharge phenomena inside vacuum interrupter at 1 to 20 Torr to simulate the vacuum leakage. We used glass type of vacuum interrupter where the internal pressure and the type of gasses can be varied according to requirement. The experiment is conducted under ac applied voltage and the experimental circuit is constructed to simulate the actual circuit used in cubical type insulated switchgear. We used two types of gases such as air and $SF_6$. The use of glass type vacuum interrupter allowed us to measure discharges occurring in vacuum interrupter optically. We measured and discussed the discharge occurring in both gases with a current transformer and ICCD camera. We also revealed that electromagnetic wave spectra emitted by the discharge have same frequency range for both gasses.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2047-2049
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• 2000

In this study, we describe comparison of insulation characteristics of polyamid papers with heating conditions. The partial discharge behavior until breakdown and breakdown strength for thermal degradation films are observed in $SF_6$ gas chamber. The four layered NOMEX films of thickness of 50${\mu}m$ were used as solid insulation films and the sphere of which diameter is 40mm to sphere electrode system was used and each insulation films were inserted between sphere electrodes. The used gas pressure was 1.0bar and used temperature was each of 250$^{\circ}C$, 270$^{\circ}C$, 300$^{\circ}C$, 320$^{\circ}C$, 350$^{\circ}C$ and the voltage were applied until breakdown films.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1951-1953
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• 2000

Partial Discharge is non-disruptive discharge, which can be discriminated to 3 kinds as firstly, internal discharge which is caused by internal voids inside of insulator, secondly, surface discharge which occurs from the surface of insulator and finally, corona discharge which is from the surface of an electrode. In this thesis, three kinds of defects are artificially made to the inside and the surface of the epoxy resine busing with internal voltage detection sensor, which is practically equipped into SF6 gas insulated switchgear for 22.9kV distribution line, so that discrimination of three kinds of PD signals by means of phi-q-n pattern analysis method was performed.

• Industrial Engineering and Management Systems
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• v.7 no.1
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• pp.34-43
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• 2008

In recent years, many electronics producing firms have looked upon total quality management (TQM) strategy as a means by which they could maintain competitive advantage. This empirical research evaluates TQM strategic factors in order to determine the critical success factors in environmental uncertainty. Fuzzy analytic hierarchy process (FAHP) is the proposed research methodology to discuss and tackle the different decision criteria like effective leadership, people management, customer focus, strategic plan and process management, being involved in identifying the TQM strategic critical success factors with uncertainty. The result shows that effective leadership is the most critical success factor in TQM strategy.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.141-142
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• 2012

다운엔더 개념설계요건 설정을 위해서 PWR $16{\times}16$ SF집합체 제원을 분석하였다. 또한 수직에서 수평으로 전환될 때 충격량을 최소화하기 위해서 모의집합체 충격실험을 수행하였다. 그 결과 수직에서 수평으로 회전되는 각속도(30초/$90^{\circ}$)를 고려할 때 평균값은 약 0.1 g, 최대 약 0.3 g 정도가 되어 거의 충격을 받지 않음을 알 수 있다. 주요 설계요건으로 그리이드(grid)에 가해지는 수평클램프(clamp) 힘은 240kg, 하부노즐에 가해지는 수직클램프 힘은 900kg 이내로 하였다. 다운엔더의 개념설계를 위해서 기구학적 특성을 반영하였고, 전환시간을 30초/$90^{\circ}$로 하였다. 원격 유지 보수성을 향상하기 위하여 Solid Works 프로그램 툴(tool)을 이용하여 5개의 주요 모듈을 구성하였고, SF 집합체 다운엔더 개념을 3D로 설계하였다.

• Journal of Aerospace System Engineering
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• v.15 no.2
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• pp.16-25
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• 2021

Reliability of fatigue strength on Aircraft Composites(GFRP) Structures was assessed in this paper. Fatigue strength of GFRP was used through the existing fatigue test data with Monte Carlo method. The S_a-N_f curve of composites fatigue strength was assumed as normal distribution and reliability was analyzed using SSIT model. Fatigue stress was designed IAW ASTM F3114-15 with special safety factor of S_sf=1.2~2.0. Reliability was calculated by analytic method and FORM. Sensitivity for the effect of mean and standard deviation of fatigue strength as well as fatigue stability was evaluated. This result can be usefully applied to reliability and fatigue design for composite structures of light weight aircraft.