• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.269-270
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• 2012

This study discussed the applicability of double layered bubble sheet(BS) to the concrete for retaining wall to verify the insulation effect as well as prevention of condensation. The BS was applied to the surface of retaining wall, which is contacted with ground. Temperature profile was monitored since placement of concrete. As expected, the application of BS helps the concrete keeping favorable heat insulating, preventing condensation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.493-496
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• 2003

Electrical characteristic of tracking resistance, volume resistance, insulation breaking strength etc. and mechanical characteristic are required to high voltage insulation insulator silicone rubber. Tracking resistance is adding much ATH to improve tracking resistance as the most important factor among them. But, there is problem that mechanical strength grows worse rapidly adding much ATH. Therefore, this research studied effect that flame retardant gets to tracking resistance during factor that influence to tracking resistance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.9
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• pp.834-840
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• 2010

The Sound reduction indices(SRIs) of interior door with 13 different size apertures are measured in acoustic chamber. Also, as a theoretical approach, the SRIs are estimated using Gomperts' theory. In this study, the aperture of interior door is focused on the lower part of door leaf which is well known as a main cause to deteriorate the sound insulation performance of door. The results show that the SRI of door strongly depends on the aperture width and the dip in the measured sound reduction index curve by the resonance effect within aperture is observed at high-frequency. On the whole, the values calculated by theory are in good agreement with the measured values including the position of resonance dip. The average difference between the measured and the calculated values is 0.9 dB for 13 doors with different size aperture in terms of the weighted SRI.

• Journal of Korea Society of Industrial Information Systems
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• v.18 no.2
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• pp.13-18
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• 2013

The authors designed a high temperature superconductor (HTS) racetrack coil for a 10 MW class superconducting synchronous wind turbine generator. The designed HTS racetrack coil was analyzed by an electromagnetic finite element method (FEM) to determine the magnetic field distribution, inductance, stress, etc. This paper describes the stress analysis and structure design result of the HTS racetrack coil for 10 MW class superconducting synchronous wind turbine generators, considering orthotropic material properties, a large magnetic field, and the resulting Lorentz force effect. Insulated HTS racetrack coils and no-insulation HTS racetrack coils were also considered. According to the results of the stress analysis, the no-insulation HTS racetrack coil results were better than the insulated HTS racetrack coil results.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.02a
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• pp.36-39
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• 2003

HTS (High Temperature Superconducting) cable termination current lead has been designed based on simplified boundary conditions such as fixed temperature at both end and sdiabatic/convection in the side wall. However, in the real situation the current lead is enclosed with insulators and exposed to insulation oil and L$N_2$. Therefore it is necessary to consider them for the proper current lead design. In this paper, several important design parameters were chosen and their effect on the temperature distribution and heat loads on the current lead has been investigated. It was found that current lead has to be 2 stage to reach the minimum temperature requirement of insulation oil and insulator is required to reduce the cooling capacity of cryogenic system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.159-163
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• 2007

We studied the example of various side on effect the aging of exterior materials for concrete structure by analyzing the reason of water leakage in exist serviced skyscraper apartment. For this side, we would like to suggest the proper waterproofing materials and construction methods resulted in the mechanical performance test. So, it could be ensured the leakage safety for using residence facility and crowd utilization after repairing. It may maximize the durability for the concrete structure.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1846-1849
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• 1998

An optical magnetic filed sensor, YIG (Yittrium Iron Garnet), response rapidly, to the power-line currents to be measured. In response to Faraday effect, it shows wide-and-linear measurable range. This paper reports the development and implementation of an OOCR (Optoelectric OverCurrent Relay) using this sensor. This relay is free from environmental electro-magnetic noises and has excellent insulation characteristics inherently. By using this OOCR, we can reduce insulation cost of protective relaying systems and its maintenance cost, and can achieve high reliability of the system.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.853-856
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• 2008

Windows have an great effect on annual building load because windows are the weakest parts of building envelope thermally. To reduce the consumption of building energy, the thermal performance of window has to be improved in first place. Therefore this research aims to make a quantitative analysis of the heating and cooling load according to the window thermal performance using the heat load simulation program. As a result of the simulation, annual heat load is down 38% according to the decrease of U-value of window, 1.00 W/$m^2K$. and annual heat load is up 10% according to the decrease of shading coefficient, 0.20. The annual load of the window with Low-E glass is 15% lower than the window with pair glass.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2191-2194
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• 2008

This paper investigates the sound insulation performance of the fiber sandwich panels for a tilting train. Due to the high strength and low mass, fiber sandwich panels are widely used for aircraft structures, railway vehicle structures. These fiber sandwich panels show orthotropic behavior because of the fiber's structural characteristics. This orthotropy often reduces the critical frequency and makes negative effect on the sound insulation performance. In this study, transmission loss of the fiber panels is analyzed based on the equivalent orthotropic plate model. An analysis program is developed to calculate the transmission loss of the fiber sandwich panels. Using the program, the coincidence frequency ranges and their effects on the transmission loss are investigated.

• KIEE International Transactions on Power Engineering
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• v.5A no.2
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• pp.171-176
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• 2005

The effects of surge arresters for the protection of transmission systems against direct lightning strokes have already been reviewed by many researchers. However, their studies have not encompassed underground cable systems. Therefore, in this paper we investigate the 22.9kV combined distribution systems that have arresters and ground wires. In addition, we analyze the overvoltages on underground distribution cable sections when direct lightning strokes contact the overhead ground wire using EMTP. Finally, we discuss the effect of lightning strokes according to the change of cable length and installation of arresters. This study provides insulation coordination methods for reasonable system design in 22.9kV underground distribution cable systems.