• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.555-560
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• 2007

This paper describes the results of a study on the sealing integrity of polymer housed surge arrester based on the thermal mechanical test. The polymer housed surge arrester employs silicone insulating materials for its housing, instead of the conventional porcelain housing. The polymer housed surge arresters exhibited the highest sealing integrity because it is not air volume between the FRP(fiber reinforced plastics) module and the silicone housing. In accordance, the sealing integrity of station class surge arresters is investigated with moisture ingress test. And, the influence of sealing integrity was evaluated through such as measurement of the deflection, reference voltage, leakage current. In electrical characteristics, reference voltage decreased in the range of $16.45{\sim}16.15\;kV$ with after thermal mechanical test. In contrary, despite the continued moisture ingress, the polymer housed surge arresters exhibited almost the same leakage current value and the resistive leakage current has risen slightly. As a results, It was thought that the polymer housed surge arresters shows good stability with sealing integrity.

• Applied Science and Convergence Technology
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• 제26권6호
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• pp.208-213
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• 2017

Flexible opto-electronic devices are developed on the insulating layer deposited stainless steel (STS) substrates. The silicon dioxide ($SiO_2$) material as the diffusion barrier of Fe and Cr atoms in addition to the electrical insulation between the electronic device and STS is processed using the plasma enhanced chemical vapor deposition method. Noble silver (Ag) films of approximately 100 nm thickness have been formed on $SiO_2$ deposited STS substrates by E-beam evaporation technique. The films then were annealed at $650^{\circ}C$ for 20 min using the rapid thermal annealing (RTA) technique. It was investigated the variation of the surface morphology due to the interaction between Ag films and $SiO_2$ layers after the RTA treatment. The results showed the movement of Si atoms in silver film from $SiO_2$. In addition, the structural investigation of Ag annealed at $650^{\circ}C$ indicated that the Ag film has the material property of p-type semiconductor and the bandgap of approximately 1 eV. Also, the films annealed at $650^{\circ}C$ showed reflection with sinusoidal oscillations due to optical interference of multiple reflections originated from films and substrate surfaces. Such changes can be attributed to both formation of $SiO_2$ on Ag film surface and agglomeration of silver film between particles due to annealing.

• Korean Chemical Engineering Research
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• 제49권1호
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• pp.120-127
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• 2011

친환경 복합단열재를 개발하기 위하여 천연섬유질(목재칩 및 톱밥)을 심재로, 활성황토를 결합재로 사용하였다. 물/결합재비 및 천연섬유질/결합재비를 다양하게 변화시켜 공시체를 제작하였으며, 공시체의 제 물성을 조사하기 위하여 압축 및 휨강도, 흡수성, 내열수성, 열전도도, 세공분포측정 및 SEM에 의한 미세조직 관찰을 실시하였다. 그 결과 흡수율은 천연섬유질/결합재비가 증가될수록 증가되었으나 폴리머/결합재비 증가에 따라 현저히 감소되었다. 압축 및 휨강도는 물/결합재비 및 천연섬유질/결합재비에 따라 다양한 특성을 나타내었다. 천연섬유질/결합재비 및 폴리머/결합재비가 증가됨에 따라 열전도도는 감소되었다. SEM조사에서 활성황토 결합재는 수화결정체가 잘 형성되어 치밀한 조직을 관찰할 수 있었고, 활성황토를 결합재로 사용한 시편의 총세공량은 생황토를 결합재로 사용한 시편의 총세공량에 비하여 적게 나타났다.

• 한국건설순환자원학회논문집
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• 제7권4호
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• pp.431-437
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• 2019

본 연구는 유기계 기재에 무기계 바인더 소재를 함침시킴으로써 유기계 수준의 경제성을 가지며 우수한 단열성능 및 화재 안전성을 보유한 유무기 융합형 단열재 개발을 목적으로 한다. 유기계 기재는 폴리우레탄 소재의 상용 스펀지를 사용하였고, 함침용 무기 바인더 용액은 재활용 석고 부산물에 물과 첨가제를 혼합하여 제조하였다. 개발 소재의 성능평가 결과 열전도율 0.051W/mK 이하의 우수한 단열성능 뿐만 아니라 국토교통부 고시 제 2015-744호 기준에 명시된 준불연 재료임을 확인할 수 있었다. 또한 본 개발 소재는 제조 공정 과정에서 밀도 제어에 따른 열전도율 및 난연성 조절이 가능하여 다양한 용도의 단열재에 적용 가능할 것으로 판단된다.

• 한국전기전자재료학회논문지
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• 제35권1호
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• pp.86-92
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• 2022

Despite otherwise advantageous properties, the performance and reliability of devices manufactured in β-Ga₂O₃ on semi-insulating Ga₂O₃ substrates may degrade because of poorly mitigated self-heating, which results from the low thermal conductivity of Ga₂O₃ substrates. In this work, we investigate and compare self-heating and device performance of β-Ga₂O₃ MESFETs on substrates of semi-insulating Ga₂O₃ and 4H-SiC. Electron mobility in β-Ga₂O₃ is negatively affected by increasing lattice temperature, which consequently also negatively influences device conductance. The superior thermal conductivity of 4H-SiC substrates resulted in reduced β-Ga₂O₃ lattice temperatures and, thus, mitigates MESFET drain current degradation. This, in turn, allows practically reduced device dimensions without deteriorating the performance and improved device reliability.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2001년도 학술대회 논문집
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• pp.45-47
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• 2001

The function of the thermal shield(TS) is to eliminate the thermal radiation from the room temperature side to the coil temperature(4.5K) region so as to reduce the thermal load on the He refrigerator. The TS is composed of multilayer insulation(MLI) which is coated very thin aluminum on the insulating material, cryopanel which is cooled by cold gaseous He, and supports which stand the cryopanel and MLI on the room temperature part. The thermal shield for the TF coils and PF coils has been located between the coils and vacuum vessel. The thermal shielding cryopanel is cooled under 80 K by a forced flow of helium gas using cooling pipes on the cryopanel.

• 대한안전경영과학회지
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• 제4권4호
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• pp.137-146
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• 2002

In order to investigate the effect of irradiation by $^{60}Co-\gamma$rays as well as the e thermal treatment on the dielectric deterioration in ethylene propylene rubber, insulating material for electric cables used in atomic power plants, charging discharging current, residual built- up voltage and dielectric properties are measu discussed in this study. Variance in the characteristic of relative dielectric constant as a function of tem was observed in relatively high dose of irradiation. Since glass transition tem appeared at tens of degree Celsius below zero, the characteristic is attributed orientation polarization. Dielectric loss is generally increased, with increasing d irradiation in the characteristic of dielectric loss as a function of temperature, No d loss by thermal treatment was observed. Dielectric resistance decreases with increa of irradiation in the characteristic of charging current as a function of temperature be considered that dielectric resistance seems to be recovered by thermal treatm characteristic of discharging current as a function of time in the specimen less ir become similar to that of the unirradiated, when thermal treated. A peak is shown residual built- up voltage as a function of time, and the corresponding time of the shorten as increasing dose of irradiation. It is also observed that the corresponding the peak is lengthened by thermal treatment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.85-85
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• 2010

In this paper, each specimen blended at weight proportions of 80% HDPE to 20% EVA, 70% HDPE to 30% EVA, 60% HDPE to 40% EVA, and 50% HDPE to 50% EVA was manufactued respectively. FE-SEM, DSC and XRD analysis were carried out as the means of structural and chemical analysis. From the results of DSC and XRD analysis, the lower contents in blended specimens were, the higher melting temperature and crystallinity of main crystal were. It seems that the phenomena was attributes to themoplastic interpenetrating network effect(TPIPN) in which EVA having low melting point penetrated into HDPE. Also, from the decreasing tendeancy of melting point as a function of blend ration, it was confirmd that above resins have compatibility. The thermal and mechanical performance of proposed insulator were compared with conventional XLPE, main insulating material of CV cable. Also, validity was proved by superior and inferior factor respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.480-483
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• 2000

Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, the electrical properties of PI LB films were investigated at room temperature. At low electric field, ohmic conduction(I∝V) was observed and the calculated electrical conductivity was about 9.7$\times$10$^{-15}$ S/cm. At high electric field, conduction(I∝V$^2$) was observed and the conduction mechanism was explained by space charge limited region effect. The dielectric constant of LB film was about 7.5.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.558-559
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• 2005

Recently, polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. In this paper, the tracking property of polymer suspension insulator for power transmission is investigated with CEA tracking wheel test. The diagnosis of insulator sample in tracking test has been analyzed by leakage current, STRI Guide, SEM, FTIR and thermal image.