• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1917-1919
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• 1996

This paper aims to extract the air clearance in 22.9KV the metal enclosed switchgear. First, we investigated the actual conditions on the clearance in the metal enclosed switchgear which has been used in domestic. The test model and 9 test electrodes for the air insulation strength tests have been designed and manufactured based on the investigation results. To find optimal clearance in the metal enclosed switchgear, we performed 50% flash-over test by the up and down method and lightning impulse withstand voltage test. And we obtained results that the clearance or phase-to-phase is 230 [mm] and clearance or phase-to-earth is 210[mm].

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2011년 춘계학술대회논문집
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• pp.512-517
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• 2011

This study is intended for validation of numerical modeling of a residential building which is made to simulate a phenomenon of fire extension from floor to floor. A common residential building which has the area of 80m2 each floor and some combustibles were chosen for numerical modeling. The combustible models were verified through comparing results of numerical simulations and real fire tests. For computational analysis, the Fire Dynamics Simulator was used with Large Eddy Simulation model for turbulence. Consequently, fire-intensity was well predicted and flash-over of rooms were successfully estimated.

• 한국분무공학회지
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• 제14권3호
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• pp.122-130
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• 2009

Vegetable oil and its derivatives as an alternative diesel fuel have become more attractive recently because of its environmental benefits and the fact that they are made from renewable resources. Viscosity is the most significant property to affect the utilization of vegetable oil and its derivatives in the compression ignition engines. This paper presents the existing correlations for predicting the viscosity of vegetable oil and its derivatives for compression ignition engines. According to the parameter considered in the correlations, the empirical correlations can be divided into six groups: correlations as a function of temperature, of proportion, of composition, of temperature and composition, of temperature and proportion, and of fuel properties. Out of physical properties of fuel, there exist in the literature several parameters for giving the influence on kinematic viscosity such as density, specific gravity, the ratio of iodine value over the saponification value, higher heating value, flash point and pressure. The study for the verification of applicability of existing correlations to non-edible vegetable oil and its derivatives is required.

• 한국전기전자재료학회논문지
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• 제18권6호
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• pp.506-509
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• 2005

This paper presents the improved burn-in method for the reliability of SRAM in Multi Chip Package (MCP). Semiconductor reliability is commonly improved by the burn-in process. Reliability Problem is very significant in the MCP which includes over two chips in a package because the failure of one SRAM chip has a large influence on the yield and quality of the other chips such as Flash Memory, DRAM, etc. Therefore the quality of SRAM must be guaranteed. To improve the qualify of SRAM, we applied the improved wafer level burn-in process using multi cell selection method in addition to the previously used methods and it is found to be effective in detecting particular failures. Finally, with the composition of some kinds of methods, we achieved the high quality of SRAM in MCP.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.296-299
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• 1987

The purpose of this paper is to increase the lamp efficacy by filling the optimal Nitrogen gas pressure in the outer enclosure of metal halide lamp. This study presents a new model of Langmuir in the outer enclosure of discharge lamp. In this paper, in the first place, the diameter of Langmuir sheath and the total gab loss were calculated. Secondly, the each gas loss was computed if the arbitrary gas pressure is filled, With the calculated data, flash over which affects the lamp efficacy, lamp life and color rendering was considered. In case of the established discharge lamp, the gab pressure has been filled by experience only roughly. The gas loss is converted into the radiation output. Therefore, the lamp efficacy is improved by reducing the gas loss.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1807-1809
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• 1997

The salt contamination on the surface of the porcelain insulators used electric power systems causes flash-over accidents. Therefore the quantity of salt contamination should be monitored not to exceed a limit. In this study, we tried laser aided measurement of salt contamination. The Nd:YAG laser beam was focused on the surface of the porcelain insulators which were artificially contaminated, and we detected the D-Line (${\cong}589nm$) of spontaneous emission from the excited sodium atoms with a PMT and an oscilloscope. And we deduced the relation between the detected signals and degree of salt contamination.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1636-1638
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• 1994

Salt deposited on the surface of insulators used in electric power system causes flash-over accidents. Therefore, the quantity of salt on insulators should be monitored not to exceed a critical value. We propose a new remote sensing technique to measure the quantity of salt on insulators of power systems. A pulsed laser beam is focussed on ah insulator to dissociate the salt to sodium atoms. The amount of the salt is measured from the intensity of the spontaneous mission from the sodium atoms. In this paper, a compact salt meter composed of pulsed Nd:YAG laser and omission signal detection system will be introduced. And measurement condition such as the sensitivity, detection range, required laser fluence will be investigated.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.2026-2028
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• 2000

As the results of evaluation of its performance for 300 kN Ball and Socket type suspension insulators. There was electrically internal puncture of the solid insulating body of the insulating due to the steep front impulse voltage, which usually occurs puncture before external flash-over of insulators, moreover we have obtained satisfactory results in power arc test of 7.2kA cycle fatigue test with high qualify control index of 4.6, especially we have obtained more satisfactory results than that before improvement of its materials.

• 한국철도학회논문집
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• 제7권4호
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• pp.302-306
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• 2004

Many long railway tunnels without emergency evacuation system or ventilation system are under construction or in-use in Korea. In the case of tunnel-fire, many fatalities are occur in current condition. Current safety level is estimated in this study, for the efficient investment on safety. But so many uncertainties in major input parameters make the safety estimation difficult. In this study, probabilistic techniques are applied for the consideration of uncertainties in major input parameters. As results of this study, accident scenarios and survival ratio under tunnel fire accident are determined for various conditions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기설비전문위원
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• pp.90-92
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• 2005

When the jacket damaged conductors in 22.9kV-y overhead distribution lines are contacted with the metal material by strong wind, which, leads to are melting as well as faults accordance. The duration of the arc temperature due to flame effected by weather and flash over conditions. In order to simulated the worst conditions, the ACSR-OC($58mm^2$) used as specimen was artificially cut in no wind. After contacting the two cut conductors again the testing current was applied. thus, the changes in temperature of are flame was analyzed.