• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2003.11a
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• pp.73-76
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• 2003

This paper is contents about method to measure interception performance of shock noise of floor slab of apartment house to be simple. In the case of interception performance of light floor impact sound level, according to measurement method, grade of sound insulation performance showed greatly differently. But, in the case of interception performance of heavy floor impact sound level, it was similar result in all measurement method. Therefore, use of simple method of measurement was examined by possible fact in case of interception performance of heavy floor impact sound level.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.432-437
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• 2001

It is necessary to improve mechanical and optical porperties in the optical disk substrates as the information storage devices with high storage density using blue laser are being developed. Injection compression molding is regarded as the most suitable process to manufacture optical disk substrates for quality recording and read-out. In the present research, the effects of processing conditions and the insulation layer thickness on gapwise birefringence and the land-groove pattern were investigated. It was found that the values of the birefringence distribution were very sensitive to mold temperature history, and the level of birefringence reduced and, furthermore, the quality of replication was improved due to the insulation layer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.682-686
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• 2002

It is increasing the interest on the comfortable dwelling environment, while sound Insulation performance of materials and elements used in building is falling down as they become thicker and lighter. Therefore, sound insulation performance in building has become the most important factor determining the level of housing, especially for apartment that has common wall and floor with next neighbors. This paper aims to experiment the sound insulation characteristics of floor coverings as their types and to analyse their noise reduction effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.88-88
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• 2010

High Voltage cross-linked polyethylene (XLPE) cables are widely used in a thermal power plant. These cables had been in service for 26 years. The insulation condition of six 6 kV XLPE cables was estimated by insulation diagnostic analyzer (IDA) with voltage amplifier. IDA was measured dissipation factor and capacitance of the whole cable as a function of frequency and voltage. This system measures in the frequency range from 0.1 to 10 Hz at each voltage level. Six XLPE cables are judged good condition, but three cables are analyzed at an aged condition.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.296-297
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• 2013

We have investigated correlation between airtightness measured by blower door and airborne sound insulation measured in the upper and lower units. We consist of two cases : all windows sealed(CASE 1) and not sealed(CASE 2). As a result, CASE 1 is tighter than CASE 2 in airtightness, but CASE 1 is lower than CASE 2 in sound level difference. This is because of big wind on measuring CASE 1. Thus we are going to measure them at another fields considering this factor. Finally we ought to find out the correlation between airtightness and sound insulation.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.33-36
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• 2015

A liquid nitrogen ($LN_2$) is usually used to be a coolant and insulant for a HTS coil system. HTS wires for a superconducting apparatus may be surrounded by gaseous nitrogen ($GN_2$) due to film boiling generated by a quench or voids occurred by electrical breakdown. The increased maximum electric field intensity at $GN_2$ may result in the degradation of dielectric strength of a HTS coil system. In this paper, a study on the dielectric characteristics of a composite insulation system composed of $LN_2$ and $GN_2$ is performed. A sphere-to-plane electrode system made with stainless steel is used to perform the experiments under AC and lightning impulse voltage condition. A sphere electrode is surrounded by $GN_2$ and a plane electrode is immersed into $LN_2$ to conduct dielectric experiments with a composite insulation system. The dielectric experiments are performed according to the level of $LN_2$ from the plane electrode to a sphere electrode. It is found that the dielectric characteristics of a composite insulation system are dependent on the level of $LN_2$ and the field utilization factor of an electrode system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.287-290
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• 2005

Housing is demanded to convert simple dwelling space into delightful one by improving of standard of living by economic development It is interested in the impact noise of the apartment housing that is revised to housing construction criteria at 29 March 2005 and then regulated the level of floor impact noise by the rule. The plan, which is actively investigated by counterplan for the reduction of impact noise, is application of sound insulation. In generally, first target by using insulation is the reduction of floor thermal transmittance in floor heating system of apartment housing. It is recently proposed soft materials that reduce the impact noise. However, it is a fact that the application of soft sound insulation includes some problem about structural performance. In this study, we made wet-heating specimen with various sound insulations, and carried out structralexperiment for evaluating the structural safety of it.

• Journal of Korea Foundry Society
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• v.30 no.3
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• pp.115-120
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• 2010

Recently, an advanced raw material supplying system in diecasting industry that molten metal produced by the raw material supplier can be directly delivered to the diecasting shops was proposed. It was known to have advantages of reducing melting process cost and improving working environment. However, for its successful mass production, the development of high insulation ladle is inevitable. In this study, the optimal mixing ratio of $SiO_2-Al_2O_3$ was investigated and the high insulation ladle with computer simulation result was built in a prototype and evaluated. The prototype which has refractory wall of $SiO_233%-Al_2O_3$ 35%-CaO 33% showed high insulation sufficient for carrying the Al molten metal for 138 minutes. Gas quantity result and SEM-EDS analysis on the melt poured in the ladle also showed extremely low level of 0.028 cc / 100 g and no penetration of Al molten metal into the refractory wall, satisfying the requirements for mass production.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.259-264
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• 2001

It is necessary to predict the sound pressure level(SPL) in rooms before designing an apartment when exterior noises are produced. In order to predict SPL for an apartment that has some specific exterior noises, the following should be known: the characteristics of outdoor noise, sound insulation performance and sound level differences of each room. The purpose of this study is to find out the possibility of predicting sound pressure level of rooms in an apartment by analysing sound level differences among rooms. Sound sources used in this experiment are construction noise, aircraft noise, railroad noise, road traffic noise and white noise as a reference to compare with the previous four. These noises were recorded and reproduced by speaker. As a result, we found that within the sound reduction pattern, the sound difference level appeared uniform depending on the sound insulation characteristics of the windows installed when facing the noise source. When the windows having the same acoustic performance were installed, the SPL in each room resulted in nearly the same values.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1208-1210
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• 1999

Design & operation power systems for meeting increase of electric power demand is becoming more difficult and complex. Some of limitations of conventional technology can be broken through by the application of superconductivity technology. This paper presents a new concept & image for the configuration of superconducting power system which has introduced superconducting(SC) generator, cable, transformer, fault current limiter(SFCL), SMES, etc. Engineering evaluation of each power apparatus and its assessment of application to power system were conducted. Futhermore, it is pointed that superconducting power system require a new operating condition. This is, SFCL should play a important part of quenching current level coordination to prevent the other superconducting devices from quenching. Its designing & operating condition including SFCL was discussed in viewpoint of quenching current level and insulation coordination of SC coil.