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.

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.

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.

VCTFK 끝단에서 발생되는 트래킹의 진전특성

지승욱(Seung-Wook Jee),김시국(Shi-Kuk Kim),옥경재(Kyung-Gea Ok),이춘하(Chun-Ha Lee),이광식(Kwang-Sik Lee) 한국조명·전기설비학회 2010 조명·전기설비학회논문지 Vol.24 No.8

본 논문은 배전선으로 널리 사용되고 있는 비닐캡타이어 타원형코드(Polyvinyl chloride insulated cabtyre oval cord, VCTFK)의 끝단에서 발생되는 트래킹의 진전특성에 대하여 언급하고 있다. 트래킹은 VCTFK의 끝단에 전해액을 적하함으로써 발생시켰다. VCTFK 끝단에서 발생되는 트래킹 진전과정 및 그 특징은 다음과 같다. 방전으로 인해 VCTFK 끝단에서 탄화가 시작되었고 침식도 일어났다. 도체에서 가까운 절연층이 먼저 침식되었으며, 피복층은 그 이후에 침식되었다. 침식이 진행된 이후, VCTFK 끝단의 표면에서 탄화물의 적층이 시작되었다. 적층 단계에서 아크를 동반했으며, 트래킹 파괴로 이어졌다. This paper describes the characteristic of tracking progress happened at the end of the polyvinyl chloride insulated cabtyre oval cord(VCTFK) that is widely used for distribution cord. Tracking is occurred owing to the drop of electrolyte at the end of the VCTFK. The tracking progress and its characteristic happened at the end of the VCTFK are as follow; Carbonization and electrical erosion are happened at the end of the VCTFK. Electrical erosion is begun at the insulation layer near conductors. After that, it is also happened at the sheath layer. Accumulation of carbonized insulation and sheath materials at the end of the VCTFK is begun after progress of electrical erosion. When the accumulation is progressed arc discharge is appeared and finally it goes to tracking breakdown.

전류 모니터를 이용한 백열등 부하 전기설비에서 사고 징후 검출에 관한 연구

지승욱(Seung-Wook Jee),옥경재(Kyung-Gea Ok),김시국(Shi-Kuk Kim),이춘하(Chun-Ha Lee),이광식(Kwang-Sik Lee) 한국조명·전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.1

본 논문은 백열등 부하 전기설비에서 측정한 전류 파형으로 전기사고 징후를 조기에 검출하기 위한 것이다. 첫째, 저항성 회로에서 전류 모니터의 특성을 분석하였다. 둘째, 백열등을 부하로 하는 전기설비를 구축하고, 전기설비의 일부에서 KS C IEC(Korea Standard C International Electrostatic Commission) 60112에 따라 트래킹을 발생시켜 사고를 모의하였다. 전기사고 징후는 전류 모니터로 측정한 전류파형을 분석함으로써 검출되었다. 그 결과 부하의 수에 관계없이 사고의 최종 단계인 트래킹으로 진전되어 갈수록 전류 파형에는 점점 큰 전류 펄스가 보였고 출현빈도도 더욱 높아졌다. This paper describes an early detection for indication of electric accident using current waveform which is measured in electric equipments consisted incandescent lamps. At first, it analyzes characteristics of current monitor in resistive electric circuit. In second, the electric equipment is consisted of incandescent lamps. And the electric accident is simulation of tracking according to KS C IEC(Korea Standard C International Electrostatic Commission) 60112 at some part of the electric equipment. The indication of the electrical accident is detected to analyzing current waveform measured by current monitor. As the tracking breakdown, electric accident, processes, as current pulse is bigger and ratio of appearance also is increased irrespective of amount of load.

장기요양시설 노인의 환자구성에 관한 연구

이지전 ( Jee Jeon Yi ),김석일 ( Suck Il Kim ),유승흠 ( Seung Hum Yu ),이상옥 ( Sang Wook Yi ) 한국병원경영학회 2001 병원경영학회지 Vol.6 No.3

This study is about major symptoms of elderly and medical services for elderly in long-term care facilities. The subject of this study was 298 patients over 60 years old staying two geriatric hospitals and two nursing homes. The symptoms and medical services were level of patient classification from RUG(Resouce Utilization Group)-Ⅲ which is applied for both Medicare and Medicaid for skilled nursing facilities reimbursement system in US and designed for measuring patient characteristics and medical staff time. This classification is explained by each patient resource(staff time) utilization level which is called CMI(Case-Mix Index). In this study, the symptoms and services were compared by facility type and they were categorized by level and compared by CMI. Major findings are as follows; 1. There were more elderly who have cognitive function problems in nursing homes than patients in geriatric hospitals. There were more patients with behavioral problems in geriatric hospitals than residents in nursing homes. These results were both statistically significant. 2. The patients in geriatric hospitals received significantly more nursing rehabilitation services, rehabilitation services and extensive services than residents in nursing homes. Other hands, special care services were provided significantly more to residents in nursing homes than elderly in geriatric hospitals. 3. ADL and depression variables had higher CMI when the syptoms were heavier condition. The CMI were not matched with levels of cognitive function problems and behavioral problems. 4. The CMI matched well significantly with levels of nursing rehabilitation services, special care services, and clinically complex services provided for the patient in geriatric hospitals and only nursing rehabilitation services in nursing homes. The CMI for rehabilitation services level and extensive services had regular trends. From the result of this study, the resource utilization level and services provided for elderly in each long-term care facilities were figured out. For the further study, it needs to have more concern about RUG-Ⅲ which classification variables were just analyzed.

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.