• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.254-255
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• 2007

This paper describes underwater discharge phenomena which are less studied than gas, solid and dielectric liquid. Since discharge phenomena were affected by various factors, we investigated the effect of water resistivity in point-plane gap by impulse voltage. In discharge photograph, it is hard to discover the streamer development in positive polarity at high reisistivity. On the other hand, the streamer originated at the tip of rod and developed toward the plane with increasing voltage. It is found that the breakdown voltage of both polarities in lower resistivity are lower than that of high resistivity. High current flowing in lower resistivity before the breakdown induce more streamer and enhance the probability of breakdown.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1436-1437
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• 2007

This paper presents the experimental results of the dielectric characteristics with temperature changes under highly non-uniform electric field in $SF_6$ gas. The impulse preliminary breakdown developments were investigated by the measurement of predischarge current and breakdown voltage. As a result, the first stremer corona is initiated at the tip of needle electrode, and bridges the test gap. Also the first stremer corona onset and breakdown voltages the negative polarity was much higher than that in the positive polarity in same temperature. In addition, the varition of temperature have a little effect on the positive polarity. On the other hand, in some cases negative polarity corona onset and breakdown voltages increased with increasing a high temperature.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.319-323
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• 2003

본 논문은 누전차단기의 충격파 부동작 특성과 전자기적합성(EMC) 특성비교에 관한 것이다 국내 규격에서는 충격파 부동작 성능만 확인하지만 국제규격에서는 많은 EMC 항목이 있다. 누전차단기 17종에 대하여 EMC 4항목을 실시한 결과, IEC 61000-4-5에 따른 조합서지 내성에서 9종이 불량이었다. 다른 항목에서는 불량이 발생하지 않았다. 오동작만 발생한 시료 2종에 대하여 충격파 부동작 성능을 평가한 결과 오동작이 발생하지 않았다. 이것으로 보아 EMC와 충격파 부동작 시험은 상관관계가 적으며 보완이 필요함을 알 수 있다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1174-1176
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• 1993

Morphology of low density polyethylene(LDPE) such as the degree of crystallinity changes with thermal history etc. In order to clarify the effects of morphological changes on electrical breakdown, we studied direct current and impulse breakdown phenomena of LDPE films heat-treated at 100[$^{\circ}C$] for 1[H] in silicone oil and subsequently cooling to various ways. The degree of crystallinity was estimated by the infra red absorption and X-ray diffraction measurements for the specimens of slowly cooled, cooled in water, original, and cooled in liquid nitrogen gas. As the result, we obtained that the first, second, third, and fourth was slowly cooled of 70.23[%], cooled in water of 61.6[%], original specimen of 56.75[%], and cooled in liquid nitrogen gas of 34.7[%] respectively. The crystalline size and distribution of specimens were researched by Differential scanning calolimeter measurements.

• Proceedings of the KIEE Conference
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• summer
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• pp.372-374
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• 2004

22.9kV 가공배전선은 여러 요소들로 구성되기 때문에 뇌격에 대한 반응도 단순하지 않다. 현재의 절연협조는 대표적인 선로모델에 패한 선로상수, 접지저항 등의 대표 값을 사용하여 EMTP로 계산한 뇌충격과전압 값을 근거로 하고 있다. 절연협조 수준에 따라 경제성이 결정되고 계산에 의한 모델해석결과는 실제의 현상과 많은 차이를 나타낼 수 있음에도 불구하고 현재의 기준은 계산과정에서 사용되는 모델과 특성 값의 유효성을 확인하는 수준에 머물고 있다. 이 연구에서는 ICG로 충격전류를 인가하여 여러 가지 경우에 애자 양단에 인가되는 과전압을 실측하였다. 실측 결과 접지특성은 애자에 인가되는 과전압에 많은 영향을 미치지 않는다는 것을 알 수 있었다.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.833-836
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• 1995

A capacitor discharge impulse magnetizer is used to produce a high current pulse of short duration in a magnetizing fixture for magnets of the various shapes. The problem of designing custom fixtures for magnetization has often been considered more of conventional experience than a scientific theory. Therefore, the design of magnetizingfixture has until recently been a "cut and try" process. It was common to literally blow up one or more fixtures beforeachieving the desired results. Finite element CAD package allow the design of such a fixture. Since magnetizing fixtures come in a variety of sizes and shapes, there is usually no simple analysis method that can be used to estimate the field characteristics of the fixtures. Instead, one typically uses finite element analysis. FEA program MAXWELL is the primary tool used here. The purpose of this study was a examine both theoretically and experimentally the field characteristics inside the fixture. Independent of sizes and shapes of magnetizing fixtures, the desired magnetic field can be obtained with resonable predictability. The experimental results have been achieved using a 1000[V], 22.4[KJ] capacitor discharge magnetizer and iron-core fixtures.

• Korean Circulation Journal
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• v.54 no.8
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• pp.427-453
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• 2024

His bundle pacing (HBP) and left bundle branch pacing (LBBP) are novel methods of pacing directly pacing the cardiac conduction system. HBP while developed more than two decades ago, only recently moved into the clinical mainstream. In contrast to conventional cardiac pacing, conduction system pacing including HBP and LBBP utilizes the native electrical system of the heart to rapidly disseminate the electrical impulse and generate a more synchronous ventricular contraction. Widespread adoption of conduction system pacing has resulted in a wealth of observational data, registries, and some early randomized controlled clinical trials. While much remains to be learned about conduction system pacing and its role in electrophysiology, data available thus far is very promising. In this review of conduction system pacing, the authors review the emergence of conduction system pacing and its contemporary role in patients requiring permanent cardiac pacing.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.4
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• pp.434-439
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• 2010

This study fabricated a simulation facility which reduced the structure of a current distribution line to 50:1 in order to analyze the induced lightning shielding effect of a 22.9kV-Y distribution line according to ground resistance capacity, grounding locations, etc. When installing an overhead ground wire, the standard for grounding a distribution line with a current of 22.9kV-Y requires that ground resistance in common use with the neutral line be maintained less than $50\Omega$every 200m span. The reduced line for simulation had 7 electric poles and induced lightning was applied to the ground plane 2m apart from the line in a direction perpendicular to it using an impulse generator. If induced voltage occurred in the line and induced current flowed through the line due to the applied current, the induced voltage and current of the 'A' phase were measured respectively using an oscilloscope. When all 7 electric poles were grounded with a ground resistance of less than $50\Omega$ respectively, the combined resistance of the line was $7.4\Omega$. When an average current of 230A was applied, the average induced voltage and current measured were 1,052V and 13.8A, respectively. Under the same conditions, when the number of grounding locations was reduced, the combined resistance as well as induced voltage and current showed a tendency to increase. When all 7 electric poles were grounded with a ground resistance of less than $100\Omega$, the combined resistance of the line was $14.9\Omega$. When an average current of 236A was applied, the average induced voltage and current of the 'A' phase calculated were 1,068V and 15.6A, respectively. That is, in this case, only the combined resistance was greater than when all 7 electrical poles were grounded, and the induced voltage and current were reduced. Therefore, it is thought that even though ground resistance is slightly higher under a construction environment with the same conditions, it is advantageous to ground all electric poles to ensure system safety.

• Asia Marketing Journal
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• v.14 no.3
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• pp.27-48
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• 2012

Temperature and weather are all around us, quite literally. Furthermore, temperature and weather not only permeate our atmosphere, constantly affecting our visceral states of warmth and coldness, but they metaphorically permeate our language. People, products, and ideas can all be "hot" or "cold." Given this ubiquity, it is perhaps surprising that relatively little research has systematically examined the influence of temperature on choice and judgment. Temperature-related words such as "hot" and "cold" are often used to describe impulsive and calculated behaviors, respectively. These metaphoric connotations of thermal concepts raise the question as to whether temperature, psychological states and decision making are related to each other, and if so, how. The current research examines these questions and finds support for a relationship. Across one field study and one laboratory experiment, I demonstrate that both hot ambient room temperature (Spa) and hot temperature primes (words) trigger decision outcomes in line with the metaphoric association between hot temperature and impulsivity. In the field study, participants were recruited in hot (40-50 degrees Celsius) and cold (10 degrees Celsius) rooms at a spa. Participants were simply asked to indicate their willingness-to-pay (WTP) for three product categories (travel package, birthday dinner, and cell phone). The results showed that participants in the hot room in comparison to those in the cold room were willing to pay more for the same products. Next, I tested if our results would go beyond ambient temperature and would hold if I were to prime temperature concepts by using a different priming method (i.e., subliminal vs. supraliminal). In line with the previous findings in the spa, participants in the hot priming condition were more likely to choose the wrong answer for the bat and baseball question than those in the cold priming condition. In addition, product type (e.g., pleasure vs. necessity) can moderate the effect of hot temperature on impulsivity. Mood and arousal did not mediate participants' responses. My findings seem to suggest that the effects of temperature on decision outcomes can be attributed to metaphoric associations rather than incidental mood or arousal. The current research applies a novel perspective in understanding the relationship between temperature and judgment and decision making. Also, the results have practical implications for packaging, advertising, merchandising, and pricing of goods and services, as well as for public policy and awareness. One of the most natural implications of my findings would be that retailers would be better off carrying more impulse purchase items on hot days. Furthermore, point-of-purchase promotions encouraging impulse purchase is more likely to be effective in retail environments with higher temperature than with lower temperature. In addition, advertisements and product packages evoking hot temperature associations (e.g., beach, sunshine, summer) might lead consumers to pay higher price for the advertised product than those with cold temperature associations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.62-67
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• 2005

Recently, polymer insulators that are used for high voltage applications have some advantages such as light weight, small size, vandalism resistance, hydrophobicity and easy making process. During outdoor service of polymer insulators, the surface of the insulating material is frequently subjected to moisture and contamination that lead to dry band arcing. Their tracking resistance, erosion resistance, end sealing and shed design are very important because dry band arcing causes degradation of polymer surface. Aging test to estimate life property of polymer insulator is executed through several international standard such as IEC 61109 and CEA tracking wheel test, but is not getting clear conclusion yet. There are two methods in the diagnosis method of polymer insulator such as off-line and on-line. The diagnosis methods in off-line are external condition analysis by the eye, contaminant analysis on surface, surface analysis, pollution withstand voltage test, power frequency flashover voltage test, lightning impulse flashover test, tensile fracture load test and flexural load test. Polymer material is also investigated it's tracking resistance by adding surface active agent in IEC 587. In this paper, the tracking performance of polymer insulator with salt solution which is added surface active agent. The diagnosis of insulator sample has been analyzed by leakage current and visual examination, STRI guide and thermal image camera.