• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.15-20
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• 2009

Entering in the time of high oil price, seriousness of an energy effect sector has given a huge impact and the importance of energy is growing. Especially, building energy occupying 24% of total demand of energy can be expected to reduce energy demand more than other section. To do this, the Building Energy Rating System is applied and implemented in Apartment houses on Jeju, South and Central region. This system calculates into energy saving rate, and certifies the building energy rating. This study evaluates the energy saving rate and rating and compares the difference in energy savings considering to each region and the thermal performance of the window. In result, the standard of the assessment house which is applied to the build energy rating system is demanded to distinguish the thermal performance of window according to regional variation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.50-54
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• 1983

Contact resistance variation which may be called sliding noise in carbon film variable resistors whose resistance elements consists of linear resistivity distribution were measured with several kinds of sliders and were analyzed to reduce the contact resistance variation. About the measuring method, the standard method of measuring contact resistance variation specified by the variable Resistance Components Institute was adupted. By analyzing the experimental results, it has been shown that the primary cause of contact resistance variation is due to current constriction and small discharge sparks in the resistance film in the area close to the slide contact. Moreover, it has been found that the sliding noise would be reduced by increasing the number of contact points, sliding speed, and pressure, and by using some kinds of insulation oil on the contacting surface. High contact resistance variation is likely to occur in the area of high resistance variation in a logrithmic resistance taper.

• The Journal of the Acoustical Society of Korea
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• v.21 no.7
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• pp.614-623
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• 2002

In this paper, it was manufactured an interferometric optical fiber sensor and measured partial discharge acoustic signal caused by defect of power facilities such as power cables, transformers and gas insulation. Acrylic and aluminium mandrels wound with fiber-optic were chosen as optical fiber sensor, Sagnac and Mach-Zehnder interferometers were chosen to detect discharge acoustic signals. The two fiber optic interferometers were identified by using the PZT. Discharge experimentation set in the discharge imitation cell in oil tank and the discharge phenomena was generated. Based on the experimental result, to detect the discharge acoustic signal, Sagnac interferometer can detect stably the acoustic signal than the Mach-Zehnder interferometer. It is shown that Sagnac optical fiber sensor can detect the discharge acoustic signals effectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.7
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• pp.636-641
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• 2000

The purpose of this study is assessing the characteristics of surface aging and recovery of hydrophobicity for silicone rubber which takes a great interest as outdoor insulation recently subjected to the combined stressed of salt fog and AC power. The methods for assessing are contact angle ATR-FRIR, AFM and XRD. In addition salt fog method is adopted as the artificial contamination experiment and AC power is applied 24 hour on and 24 hour off repeatedly for 5 cycles. The results suggest that degraded surface was more rough than virgin but was restored water repellency through the off cycle. It was due to not only the formation of fractal surface but also maintenance of hydrophobic surface by diffusion of low molecular oil. Although surface recovers initial hydropohbicity there are possibilities of decreasing electrical performance due to irreversable changes such as depolymerization of surface and loss of filler particles. This fact is confirmed by surface conductivity measurement showing that the degradation is significant and the recovery of hydrophobicity is imperfect as the energized cycle increases.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1609-1611
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• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) system of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system, Boding ICCP system. In this paper, the mechanism of mitigation method of DC stray current for underground metallic structures is described.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1612-1614
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• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) design of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system. We installed the mitigation system at the real field and test of its efficiency in Busan and Seoul, Korea. In this paper, the results of field test, especially, distributed ICCP system is described.

• Journal of the Korea Furniture Society
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• v.24 no.1
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• pp.60-69
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• 2013

Timber is an eco-friendly material that is suitable for low carbon and green growth, and recently, studies on utilization and manufacture of timber are increasing. Thus, we need a stable supply of wood working materials for the formative element and widespread function of timber. It is necessary to develop the use of timber because it enhances the added value of this material by making the most of it. In this way, skin-timber is an appropriate material for life articles because skin-timber has a variety of functions including the ability for storage use, the beauty of structure, the ability to maintain heat and insulation, and the capability to control humidity. In this study, I developed household items using skin-timbers that are made up of circular columns and square columns of pine, larch, and yellow popular. The circular and square columns have an inner hole that is approximately 90% of the external structure's width. I intended for the concept of these designs to display creativity considering functionality and productivity. These items are life articles and furniture for modern people. They are eco-friendly products that are varnished with traditional lacquer and natural oil. According to the result of this study, skin-timbers are made of domestic pine, larch, and yellow popular and are resource of furniture, household items, and woodcraft. I believe skin-timber is not only a useful material for processability and design applicability, but it also has the capability to be a multifunctional and high value-added material. Also, if the standards, such as cortex thickness, outside diameter, and length, of skin-timber are producted diversely, I believe skin-timber can be have more the possibility of industrial products' development.

• Transactions on Electrical and Electronic Materials
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• v.14 no.6
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• pp.308-311
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• 2013

The effect of an electric field on the ac electrical treeing in various epoxy/reactive diluent systems was studied in a needle-plate electrode geometry. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE was acted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the treeing initiation time and the propagation rate, three constant alternating currents (ac) of 10, 13 and 15 kV/4.2 mm (60 Hz) were applied to the specimen, in a needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. When 10 kV/4.2 mm (60 Hz) was applied, the treeing initiation time and the propagation rate in the DGEBA system were 356 min and $1.10{\times}10^{-3}$ mm/min, respectively, those in the DGEBA/BDGE system were 150 min and $1.14{\times}10^{-3}$ mm/min, respectively. Those in the DGEBA/PG system were 469 min and $1.05{\times}10^{-3}$ mm/min, respectively. As 15 kV/4.2 mm (60 Hz) was applied, the propagation rate in the DGEBA system was $5.41{\times}10^{-3}$ mm/min, and that in the DGEBA/PG system was $1.42{\times}10^{-3}$ mm/min. These values meant that PG could be used as a reactive diluent in the DGEBA system, without the deterioration of the insulation breakdown property.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.184-192
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• 2012

For use as recyclable power cable insulations without dielectric oil, technology trends of IPP based thermoplastic polyolefin elastomer(TPO) nanocomposites were reviewed. In 2010 research results of IPP nanocomposite dielectrics for power capacitors showed promising high voltage properties except dielectric loss. Research of IPP based TPO nanocomposites for automotive exterior parts revealed considerable improvements of mechanical properties including impact strength, especially minimization of compatibilizer content, the origin of dielectric loss. A study on electrical properties of IPP based TPO nanocomposites containing a few weight percent of nanofillers for power cable insulations is suggested.

• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.9-14
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• 2011

Heavy duty diesel engine has relatively small portion of whole vehicles due to long drive distance and large engine displacement, but largely influences atmosphere environment. City buses changed to CNG (Compressed Natural Gas) bus with Korea-Japan Worldcup. Heavy duty truck and intercity bus, however, were impossible to use CNG because those kinds of vehicles had long drive distance and CNG station was installed mainly at the around of the bus garage of city. Insulation container storing the natural gas as a liquid makes heavy duty truck and intercity bus possible to use the natural gas. Drive using diesel is possible where is hard to recharge the gas. With LNG (Liquefied Natural Gas), the dependence on oil is largely decreased, PM (Particulate Matter) and NOx which is chronic disadvantage of diesel is remarkably reduced and finally $CO_2$, the representative green house gas, is reduced over 10%.