• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.896-899
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• 2002

Microcellular foaming Process has several merits, impact strength elevation, thermal insulation, noise insulation, and raw material saving etc. This method make the glass transition temperature of polymers low, and diminish the residual stress of polymers. This characteristics of Microcellular foaming process influences the physical properties of recycled polymers. This paper describes about the impact strength change of Microcellular foamed recycled ABS.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.232-235
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• 2003

To realize the development of HTS power apparatus, various breakdown test of L$N_2$ should be carried out and the mechanism should be understood more. Moreover the dielectric design technology that the basic dielectric experimental data applied to the HTS power system should be developed. In this paper, the electric fields for the insulation design were calculated for example with the analysis of Weibull distribution. And V-t characteristics of L$N_2$ were discussed. Around the breakdown voltage the n values were less than 1.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.391-394
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• 2000

EPDM/silicone blend was prepared with polyorganosiloxane compatibilizer for out-door polymer insulation used to shed. Each blend had various weight ratios, 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100 as EPDM to silicone, and electrical and tracking characteristics were studied with the method of IEC 60587. And also, tracking properties and contact angle related to UV-weathering period were studied to understand the degree of degradation of blend after 1000 h UV-weathering.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.882-887
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• 2001

This paper deals with the effect of mass-spring-mass resonance that is a characteristics of the multi-layered panels in order to enhance sound insulation performance. From theoretical and experimental investigation, it is evident that tuning mass-spring-mass resonance by controlling elastic modulus of the core materials is very important to improve the STC value without increasing the weight of panels, resulting in enhancing STC value more than 10 dB.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2002.05a
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• pp.15-15
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• 2002

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2001.11a
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• pp.4-4
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• 2001

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.9
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• pp.558-565
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• 2017

Hybrid insulators that have the advantages of both porcelain (high mechanical strength and chemical stability) as well as polymer (light weight and high resistance to pollution) insulators, can be used in place of individual porcelain and polymer insulators that are used for both mechanical support as well as electrical insulation of overhead power transmission lines. The most significant feature of hybrid insulators is the presence of porcelain/polymer interfaces where the porcelain and polymer are physically bonded. Individual porcelain and polymer insulators do not have such porcelain/polymer interfaces. Although the interface is expected to affect the mechanical/electrical properties of the hybrid insulator, systematic studies of the adhesion properties at the porcelain/polymer interface and the effect of the interface on the insulation characteristics and electric field distribution of the hybrid insulator have not been reported. In this study, we fabricated small hybrid insulator specimens with various types of interfaces and investigated the effect of the porcelain/polymer interface on the microstructure, insulating characteristics, and electric field distribution of the hybrid insulators. It was observed that the porcelain/polymer interface of the hybrid insulator does not have a significant effect on the insulating characteristics and electric field distribution, and the hybrid insulator can exhibit electrical insulating properties that are similar or superior to those of individual porcelain and polymer insulators.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1560-1565
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• 2011

The environmental pollution caused by green-house gases such as $CO_2$ and $SF_6$ has been becoming the main issue of industrial society. Many developed countries are making efforts to minimize the amount of $CO_2$ emission come from the operation of high voltage electrical apparatuses. As a part of these efforts, 180 countries signed the Kyoto Protocol in 1997 to cut back on their green-house gas emissions. Nowadays, the study on the development of dry air insulated switchgear (DAIS) which is known as an eco-friendly electrical apparatus is in progress. A DAIS is advantageous for minimizing the effect of impurities and enhancing the dielectric characteristics over an air insulated switchgear (AIS) by applying constant pressure to an enclosed cubicle. Therefore, a study on the electrical insulation performance of dry air as a gaseous insulation medium is conducted in this paper to substitute a gas insulated switchgear (GIS) for DAIS. As results, it is verified that the AC dielectric characteristics of dry air are similar to those of air and the lightning impulse dielectric characteristics of dry air are superior to those of air at 1bar pressure condition. However, dry air is of inferior dielectric characteristics to $SF_6$ at 4bar pressure condition. Finally, it is suggested that the internal pressure of DAIS should be over 4bar pressure to develop a high voltage switchgear which has similar electrical performance to a conventional GIS. Also, the empirical formulae on calculating the maximum electric field intensity at sparkover of dry air are deduced by experiments according to pressures. It is expected that these results are helpful to design and develop a high voltage electrical apparatus.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.301-306
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• 2014

Recently in accordance with the rapid development of the industrial society, the accidents caused by dielectric breakdown have been increasing in power grid. It is important to prevent the dielectric breakdown of a high voltage apparatus to reduce the damage from electrical hazards. To establish an electrically reliable database of insulation design criteria for high voltage apparatus, a study on dielectric characteristics test is indispensable. In this study, dielectric characteristics according to field utilization factors (${\xi}$) which are represented as the ratio of mean electric field to maximum electric field are investigated. the dielectric breakdown experiments by using several kinds of electrode systems made with stainless steel are performed by AC breakdown voltage under air-insulation. Also, the experimental results are analyzed by the Weibull distribution. As a result, it is found that the dielectric characteristics of air-insulation are determined by ${\xi}$ as well as arrangement of electrode systems. It is considered that the results of this study would be applicable to designing the air-insulated high voltage apparatuses.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.120-126
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• 2012

BIPV is applied to buildings in various forms. However, there are some aspects of consideration in applying PV systems in buildings, such as attaching methods, PV electrical efficiency, appearance and so on. BIPV can be installed on curtain wall spandrel as finishing material, which may combine with insulation. The thermal characteristic of spandrel with BIPV has rarely been studied; the temperature of air space between PV module and insulation layer affects both the electrical behavior of PV module and the energy load in a building. This paper aims to analyse the temperature variation of the layers in BIPV spandrels. In this paper, the temperature of layers, including the air space and PV module, was measured for three different type of BIPV applications on spandrel. The results show that the temperature of air layer for the spandrel with G/G(2) type BIPV module on October was the highest among other months.