• 한국안전학회지
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• 제32권4호
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• pp.16-21
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• 2017

The sprinkler system is a basic fire extinguishing system that uses water as an extinguishing agent. In order to evaluate the fire extinguishing performance of the sprinkler system, information such as the discharge angle, discharge speed, discharge pressure, flow rate, and water droplet size of the installed head are required. However, there is a lack of research on droplets size compared to other requirements. In this study, to evaluate the extinguishing characteristics of sprinkler system, the droplet size distribution was measured for various types of sprinkler heads actually used. The size of the droplet was measured using laser diffraction method. The 50% cumulative volume distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the distribution ($D_{v50}$) according to discharge coefficient(K factor) was $540{\mu}m{\sim}695{\mu}m$ for K50, $542{\mu}m{\sim}1,192{\mu}m$ for K80, $980{\mu}m{\sim}1,223{\mu}m$ for K115 and $1,188{\mu}m{\sim}1,234{\mu}m$ for K202. Based on the measured results, the vaeiance of the droplet particle distribution and the Rosin-Rammler index value are presented. As a result of the fire simulation with FDS, it was confirmed that the performance difference occurs according to the water droplet size distribution even when the same amount of water is used. Therefore, the extinguishing performance of the sprinkler system should be evaluated considering the droplet size distribution according to the sprinkler head type.

• 한국전자통신학회논문지
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• 제10권12호
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• pp.1337-1344
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• 2015

Li-ion 배터리를 생산하는데 있어서 충/방전을 통한 formation 과정이 필요하다. 이 과정에서 방전기의 부하 저항을 통해 방전하게 되는데 이때 에너지 손실이 발생한다. 따라서 본 논문에서는 DC ${\mu}-Grid$ 기반의 충/방전 시스템에서 배터리를 효율적으로 운영하는 방안에 대해 연구하였다. 컴퓨터 시뮬레이션 결과, DC ${\mu}-Grid$ 기반의 충/방전 시스템에서 충전 배터리 set 3개 기준 대비 방전 배터리 set의 수가 133%를 초과하게 되면 망 전압이 안정화되는 과정에서 발생하는 전압 fluctuation 폭을 초과하기 때문에 시스템에 치명적인 손상을 야기한다. 따라서 충전 배터리 set 3개 기준 대비 방전 배터리 set의 수를 133%까지 운영할 수 있으며 획기적인 에너지 절감 효과를 확인할 수 있었다.

• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.1035-1042
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• 1998

After the 1990's, a computer-aided partial discharge(PD) measurement system was referred in part of aging diagnosis using digital signal processing as the new technology has been studied. The PD patterns and relevant information for pattern recognition are discussed in PD research area, because discharge quantity(q), the number of discharge pulse(n) and the applied boltage phase($\varphi$) was combined with the system information of the aging state. This paper investigates the discharge phase and quantity, as well as the number of discharge(n) with regard to discharge signals generated in power cable. therefore, according to characteristic analysis on the distribution of $\varphi$, q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

• 대한화학회지
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• 제38권3호
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• pp.214-220
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• 1994

금속시료를 직접분석하기 위하여 원자흡수법에 의한 글로우방전시스템을 구성하였다. 방전이 일어나는 양극과 음극은 가공성 세라믹을 이용한 arrestor에 의해 분리하였으며, 방전에 영향을 미치는 전류 및 전압, arrestor의 형태, 가스 압력 그리고 가스 흐름 등을 개인용 컴퓨터와 ADC/DAC board 및 RS-232를 사용하여 자동적으로 제어될 수 있도록 하였다. 여러가지 방전에 미치는 실험변수들을 변화시키면서 시료손실속도, 원자흡광도 등의 변화를 측정하였으며, sputtering 된 후의 시료 표면을 주사형 전자현미경으로 관찰하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.746-752
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• 2000

A study on discharge characteristics of a rotating discharge hole is very important to enhance the performance of an induction motor which have external forced cooling system. The discharge characteristics of rotating discharge holes are influenced by rotating speed, length-to-diameter ratio, inlet shape of rotor holes, etc. An experimental study on the effect of chamfered inlet edge of rotor inlet part with various depth-to-diameter and inlet chamfered edge angle is conducted. Depth-to-diameter ratios range from 0 to 0.5 and inlet chamfered edge angle range from 0 to 60. As a result, there is an optimal design point of inlet chamfered edge depth. And the inlet edge angle far maximum discharge coefficient is influenced mainly by the rotating speed of discharge holes.

• 대한전기학회논문지
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• 제35권12호
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• pp.560-566
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• 1986

In the design of an RF discharge system, the electrical equivalence of the gas discharge must be known. With this knowledge, one can design a suitable matching network for a maximum power transfer from the RF generator into the discharge. For this purpose, an experiment has been conducted in which the electrical impedance (conductance and capacitance) was determined as a function of power. In parallel with this, a detailed theoretical analysis has been done and the results are in accord with those of our experiment. Design equations are also given for a simple matching network, and a design example is presented to demonstrate its application. During the actual operation of an RF discharge system, however, it has been often observed that the reflected power tends to vary in small values due to the changes in the impedance of the system. This problem can be relieved by adding an automatic impedance matching circuit to the system and this paper presents such an automatic impedance matching network.

• 전기학회논문지
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• 제59권3호
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• pp.599-603
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• 2010

A point-mesh type corona system has been well used as a ionic wind blower. However this type corona system suffers from its lower ionic wind generation, because of its lower on-set and breakdown voltages of its very sharp needle point corona electrode. This means that the point corona electrode must act both as an effective ion-generator and a very higher electric field producer in the discharge airgap in order to generate higher ionic wind velocity. In this paper, a cylinder-mesh type discharge system as a ionic wind generator is proposed and investigated. The cylindrical corona electrode can produce many ions from its sharpened edge, and the corona on-set and breakdown voltages are very higher than those of the needle point corona electrode. As a result, this type cylindrical corona electrode might generate a higher ionic wind than the needle point corona electrode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1930-1932
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• 2000

PD in defects of solid insulation system is very harmful since it leads to deteriorate insulation system by. the discharge electrons and ions bombarding the insulation surface and the action of chemical products that are formed by discharges. PD is used to detect and recognize defects and degradation of insulation system However, there are still marked difficulties to recognize defects by PD methode. In this paper, we investigated properties of PD of defects in solid insulation by using statical methods and classified PD patterns of surface discharge, electrical tree and void discharge with source of discharge, we used specific distributions such as $H_n(q)$, $H_{an}(\phi)$, $H_n(\phi)$, $H_a(\phi)$ to recognize defects of solid insulation system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기설비전문위원
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• pp.99-102
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• 2005

In order to development of diagnosis system for mold transformer, partial discharge measurement technique is recommended the best effective method for the evaluation of insulation condition on high voltage winding part. However, this technique was not applied to mold transformer yet. The purpose of this paper is to describe the method of partial discharge measurement for mold transformer with coupling sensor and measuring system. As we reviewed and developed the on-line partial discharge test technique, ceramic coupling sensor, measuring system, terminal box and index parameters.

• 디지털융복합연구
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• 제20권2호
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• pp.399-405
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• 2022

본 연구는 재활용 의무 대상 제품 포장재의 재활용 분리 체계에 대하여 사용자 관점에서 새로운 디자인 가이드라인을 제시하는 것이다. 국내 사례는 현행법과 재활용 분리배출에 대한 문헌을 사전 연구하였고, 국외 사례는 아시아, 유럽, 북아메리카 대륙에서 재활용 분리배출에 대한 성과를 거둔 도시를 각각 1개씩 선정 조사하였다. 사용자의 긍정적인 참여 결과의 피드백과 올바른 분리배출에 관한 보상이라는 사용자 중심 디자인관점에서 ID(Identification) 사용자 분리배출 체계를 제안한다. 이 체계는 명시된 개인식별 코드가 부착된 분리배출 전용 용기와 개인용 애플리케이션을 이용한다. 사용자는 분리배출 전용 용기에 기재된 분리배출 표시와 분리배출 요령에 따라 해당 분리배출 품목을 전용 용기에 배출하며, 선별처리 결과가 사용자에게 통보되고, 이에 따른 보상이 이루어지는 체계이다. 이 분리배출 체계는 사용자의 적극적인 참여를 유발할 수 있는 분리배출 체계라는 의미를 가진다.