건전지의 본질안전 방폭성 평가에 관한 연구

지승욱,이광식,이동인,박원주,이춘하,김하호 嶺南大學校 工業技術硏究所 1997 工業技術硏究所論文集 Vol.25 No.1

Ignitability of explosive gas mixture by spark of dry cell in case of short circuit by accident was studied for the purpose of evaluation of intrinsically safe characteristics of dry cell that manufactured in Korea. IEC type spark test apparatus, 21±2[vol%] of hydrogen-air mixture, and dry cell that produced in Korea was used for the experiment. The result of this research could be used for design, manufacturing and using the intrinsically safe electrical apparatus.

림프관 확장증형 모기질종 1예

김도현,김재욱,이지범,김성진,원영호,이승철 대한피부과학회 2003 大韓皮膚科學會誌 Vol.41 No.2

Pilomatricoma is a benign adnexal tumor differentiating toward elements of the hair matrix and shaft. It typically presents as a solitary, deep, dermal nodule, but other variants, such as anetodermic form and pseudo-bullous form have rarely been reported. A 22-year-old man presented with erythematous 4×5㎝ sized bulla-like nodule of about 1 month history on the upper back. Histopathologic examination of the lesion showed a well-circumscribed dermal nodule composed of basophilic cells, shadow cells, and transitional cells. There were also marked lymphangiectatic dilatations above the tumor in the upper dermis. We diagnosed this case as a lymphangiectatic pilomatricoma with pseudo-bullous appearance. (Korean J Dermatol 2003;41(2) : 258∼260)

저항을 이용한 프로판-공기 혼합가스의 점화한계 개선에 관한 연구

이춘하,오종용,옥경재,지승욱,이광식,심광렬 한국화재소방학회 2004 한국화재소방학회논문지 Vol.18 No.1

본 논문은 IEC형 불꽃점화 시험장치를 이용하여 저압 유도회로의 최소 점화한계를 프로판-공기 5.25 Vol.%의 혼합 가스에 대하여 실험적으로 구하였으며, 또한 유도회로의 인덕턴스 L에 안전소자로서 저항을 병렬접속하였을 경우 프로판-공기 5.25 Vol.%의 혼합 가스에 대한 점화한계 개선효과를 관찰하였다. 그 결과, 최소 점화한계는 전류의 크기에 따라 좌우되었다 또한, 전원으로부터 공급되는 에너지는 인덕턴스에 우선 축적되고. 그 초과분의 에너지가 폭발성 가스의 점화원으로 작용하였다. 점화한계 개선효과는 인덕턴스가 300 mH일 때, 최고 330%의 개선효과가 나타났으며 인덕턴스가 클수록 점화한계 개선효과가 크게 나타났다. 또한 병렬로 접속한 저항의 크기가 적을수록 점화한계 개선 효과가 크다. 본 연구결과는 본질안전 방폭형 전기기기의 연구개발을 위한 기본자료로 활용할 수 있을 뿐만 아니라 이들 기기의 방폭성능에 대한 시험자료로도 활용이 가능할 것으로 사료된다. This paper describes the minimum ignition limits for propane-air 5.25 Vol.% mixture gases in low voltage inductive circiuts. The improved effects on the ignition limit are studied by parallel safety components(resistors) for propane-air 5.25 Vol.% mixture gas in low voltage inductive circuits. The experimental devices used in this test are the IEC type spark ignition test apparatus. The minimum ignition limits are controlled by the values of current in inductive circuit. Energy supplied from elect source is first accumulated at the inductance, it's extra energy is working as ignition source of the explosive gas. The improved effects on the ignition limit are respectively obtained as the maximum rising rate of 330% by composing parallel circuits between inductance and resistor as compared with disconnecting inductance with the safety components. The more values of inductance increase the higher improved effects of ignition limit rise. The less values of resistor the higher improved effects of ignition limit rise. It is considered that the result can be used for not only data for researches and development of intrinsically safe explosion-proof machines which are applied equipment and detectors used in dangerous areas but also for datum for its equipment tests.

The Effect of Guard on Improving the Resistance to Tracking Phenomenon for the PCB

Jee Seung-Wook 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.1

As the need for safe and eco-friendly transportation increases, the electronization of transportation sector is expected to increase explosively. This will lead to increase the use of printed circuit boards (PCBs). The PCBs used for transportation have a poor operating environment, but are required long-term reliability. Therefore, PCBs used in transportation are required to have strong resistance to tracking phenomenon from moisture or contamination. A basic sample was fabricated using a PCB and characteristics of tracking phenomenon were investigated. An improved sample with a guard installed on the basic sample was made, and the resistance to tracking phenomenon was measured experimentally. The function of the guard was investigated through thermal distribution analysis, electric fi eld analysis, and current waveform measurement. By using the guard, the resistance to tracking phenomenon of the PCB increased by approximately 2.88 times. The guard changed the location of the dry band by conducting heat to the outside and retaining the electrolyte at the electrode tip. The strength of the discharge was weak, and the discharge appeared dispersed. As a result, the generation and growth of carbonization were delayed. The resistance to tracking phenomenon of the PCB used for transportation could be improved by using the guard. And the result of this study can be used as the basic knowledge necessary to implement this improvement in the PCBs

Classification of Bridge Current and Analysis of Heat Transfer Characteristics in Polyvinyl-Chloride-Sheathed Flat Cord Under Tracking

Seung-Wook Jee 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.1

In this study, we examine the tracking happen in a polyvinyl-chloride-sheathed flat cord (PVCSFC), which is widely used as a distribution cord. The study classifies the bridge current via the formed conductive paths during tracking in the PVCSFC. Further, it attempts to distinguish the characteristics of heat generation and heat transfer by kind of bridge current. When the PVCSFC is in the static state, the bridge currents flow only through the electrolyte bridge. In the case of the carbonized PVCSFC, the bridge currents flow through one or more conductive paths. One is the electrolyte bridge, the other is the bridge that is consisted electrolyte and carbonized insulation. Currents flowing through different conductive paths have different heat generation and transfer characteristics. As the bridge current flowing in the conductive path consisting of electrolyte and carbonized insulation increases, the temperature difference between the surface of the PVCSFC and ambient air also increases correspondingly.

Classification of Bridge Current and Analysis of Heat Transfer Characteristics in Polyvinyl-Chloride-Sheathed Flat Cord Under Tracking

Jee, Seung-Wook,Lee, Chun-Ha,Lee, Kwang-Sik The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.1

In this study, we examine the tracking happen in a polyvinyl-chloride-sheathed flat cord (PVCSFC), which is widely used as a distribution cord. The study classifies the bridge current via the formed conductive paths during tracking in the PVCSFC. Further, it attempts to distinguish the characteristics of heat generation and heat transfer by kind of bridge current. When the PVCSFC is in the static state, the bridge currents flow only through the electrolyte bridge. In the case of the carbonized PVCSFC, the bridge currents flow through one or more conductive paths. One is the electrolyte bridge, the other is the bridge that is consisted electrolyte and carbonized insulation. Currents flowing through different conductive paths have different heat generation and transfer characteristics. As the bridge current flowing in the conductive path consisting of electrolyte and carbonized insulation increases, the temperature difference between the surface of the PVCSFC and ambient air also increases correspondingly.

통전중인 도선에서 화재 가능성에 관한 기초 연구

지승욱(Seung-Wook Jee),김시국(Shi-Kuk Kim),이춘하(Chun-Ha Lee),이광식(Kwang-Sik Lee) 한국조명·전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.6

2006년 우리나라에서 발생된 전기화재 중 63.2[%]는 전기배선에서 단락에 의해 발생되었다. 따라서 전기배선에 의한 화재가능성에 대한 연구가 필요하다. 이에 본 연구에서는 통전중인 도선이 주변 조영재와 접촉할 가능성 및 접촉에 의한 화재가능성에 대하여 연구하였다. 그 결과 도선에 흐르는 전류가 클수록 주변의 조영재와 접촉할 가능성이 높고 특히, 도선의 온도가 도선피복의 발화점을 넘는 경우 도선과 주변 조영재 간에 불꽃을 동반하는 방전이 발생됨으로써, 전기화재 가능성이 더욱 커지는 것을 실험적으로 알 수 있었다. In total electric fire in Korea in 2006, a rate of the electric fire caused of short in electric wire is over 63.2[%]. It is needed to study a fire potentiality in electric wire. This paper studies contact and fire potentiality between a electric wire and conductors existed around the electric wire. As amplitude of current in electric wire is bigger, as it has higher possibility to contact between a electric wire and conductors existed around the electric wire. In case of temperature of wire is over combustion point of outer sheath, it is appeared to spark discharge between wire and conductors. So the fire potentiality raise up.

장애경보 방지를 위한 연소 연기입자와 비연소 연기입자의 광 특성 분석

지승욱(Seung-Wook Jee) 한국조명·전기설비학회 2014 조명·전기설비학회논문지 Vol.28 No.10

This paper is basic study for development of an advanced photoelectric type smoke detector that has high reliability by reducing the occurrence of nuisance alarms. This paper was attempted to distinguish optical characteristics of the typical fire smoke particle and non-fire smoke particle. According to UL 268 standards, three types of test fires (the paper, the wood and the flammable liquid) were used in this paper for measurement of the fire smoke particles, and the water vapor and the cigarette smoke that were known as the main cause of the nuisance alarms were also used for the non-fire smoke particles. A smoke detection chamber was created, which was equipped with one light source and several light sensors for enabling simultaneous detection of light extinction and scattering, respectively. This paper analyzes the optical characteristics of each smoke particle using this chamber.

실시간 상황 인식을 위한 하드웨어 룰-베이스 시스템의 구조

이승욱(Seung Wook Lee),김종태(Jong Tae Kim),손봉기(Bong Ki Sohn),이건명(Keon Myung Lee),조준동(Jun Dong Cho),이지형(Jee Hyung Lee),전재욱(Jae Wook Jeon) 한국지능시스템학회 2004 한국지능시스템학회논문지 Vol.14 No.5

본 논문에서는 실시간으로 상수 및 변수의 병렬 매칭이 가능한 새로운 구조의 하드웨어 기반 룰-베이스 시스템 구조를 제안한다. 이 시스템은 context-aware computing 시스템에서 상황 인식을 위한 기법으로 적용될 수 있다. 제안한 구조는 기존의 하드웨어 기반의 구조가 가지는 룰의 표현 및 룰의 구성에서 발생하는 제약을 상당히 감소시킬 수 있다. 이를 위해 변형된 형태의 content addressable memory(CAM)와 crossbar switch network(CSN)가 사용되었다. 변형된 형태의 CAM으로 구성된 지식-베이스는 동적으로 데이터의 추가 및 삭제가 가능하다. 또한 CSN은 input buffer와 working memory(WM) 사이에 위치하여, 시스템 외부 및 내부에서 동적으로 생성되거나, 시스템의 설정에 의해 지정된 데이터들의 조합 및 pre-processing module(PPM)을 이용한 연산을 통하여 WM을 구성하는 데이터를 생성시킨다. 이 하드웨어 룰-베이스 시스템은 SystemC ver. 2.0을 이용하여 설계되었으며 시뮬레이션을 통하여 그 동작을 확인 및 검증하였다. Context-aware computing systems require real-time context reasoning process for context awareness. Context reasoning can be done by comparing input information from sensors with knowledge-base within system. This method is identical with it of rule-based systems. In this paper, we propose hardware rule-based system architecture which can process context reasoning in real-time. Compared to previous architecture, hardware rule-based system architecture can reduce the number of constraints on rule representations and combinations of condition terms in rules. The modified content addressable memory, crossbar switch network and pre-processing module are used for reducing constraints. Using SystemC for description can provide easy modification of system configuration later.

브리지 특성이 트래킹에 미치는 영향에 관한 연구

지승욱(Seung-Wook Jee),옥경재(Kyung-Gea Ok),이춘하(Chun-Ha Lee),이광식(Kwang-Sik Lee) 한국조명·전기설비학회 2008 조명·전기설비학회논문지 Vol.22 No.8

본 논문은 전해액에 의해 양전극 사이에 형성되는 브리지가 트래킹에 미치는 영향을 기술하고 있다. IEC(International Electrotechnical Commission) 60589의 방법으로 만들어진 1, 3, 5[wt%] NaCl 용액을 이용하여 KS C IEC 60112의 전극에서 트래킹 실험을 하였다. 트래킹 진전과정 중에서 브리지가 형성되었을 때의 전압, 전류, 저항 및 열화상을 측정하여 분석하였다. 그 결과 전해액의 전도율이 커짐에 따라 브리지에서 발생되는 줄열도 커졌다. 하지만 전해액의 기화열로 인해 전해액의 끓는점을 넘지는 못했다. 다만, 전해액의 전도율이 커짐에 따라 건조대 형성에 소요되는 시간이 짧아졌다. 따라서 다음 적하까지 보다 긴 시간동안 건조대를 유지함으로써, 방전 기회가 증가하기 때문에 트래킹 진전이 빨라짐을 알 수 있었다. This paper describes the influence of the bridge formed between electrodes by electrolyte for tracking process. Electrolytes is made by IEC(International Electrotechnical Commission) 60589, NaCl added to deionized water as each 1, 3, 5[wt%]. The used test equipment is made according to KS(Korean Industrial Standard) C IEC 60112. It is investigated voltage, current, value of resistance and thermal image when bridge formed between electrodes on tracking process As a result, as conductivity of electrolyte gets bigger as Joule’s heat on bridge also gets bigger. But It is not over electrolyte’s boiling point clue to evaporation heat of electrolyte. However as conductivity of electrolyte gets bigger as the necessary time of dry band gets shorter. So dry band is existed more long time between ahead of droplet to next droplet and discharge chance at dry band gets much. Therefore tracking process gets faster.