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최근 10년간 원광의대병원에서 시행한 소아 심장혈관 수술의 임상적 고찰
윤향석,정수미,최두영,오광수,오연균,김종덕,양현웅,이삼윤,김형곤,최종범,최순호,노병석 圓光大學校 醫科學硏究所 1995 圓光醫科學 Vol.11 No.2
We reviewed 10 years experiences of the clinical aspects and early postoperative results in 544 pediatric patients(age less than 16 years old). Among them. 529 cases had the congenital heart diseases, and 15 had the acquired diseases. Open heart surgery was performed in 413 patients. 115 cases were treated with non-open heart surgery. 16 with interventional catheterization. Annual increase of the cardiac patients was not significant in recent 10 years, except slight increase in 1994. The mean age of the study patients had been evidently changed to younger year by year. Total mortality rate of the open heart surgery was 6.4%. The cyanotic congenital heart diseases were high in early postoperative mortality by 25.7%, whereas 4% in acyanotic group. The age group less than one month was most highest in surgical mortality(66.7%). There were no deaths in patients with patent ductus arteriosus(103 cases), atrial septal defect(83 cases) or pulmonary stenosis(17 cases). Among 220 patients with ventricular septal defects(VSD). 10(4.5%) were died early postoperatively. In cyanotic group, the patients with pulmonary atresia with ventricular septal defects(PAVSD), transposition of the great arteries(TGA), interrupted aortic arch(IAA), complex cardiac anomalies with isomerism seemed to be most susceptible to an early death.
최충석,김향곤,김동욱 한국안전학회 2004 한국안전학회지 Vol.19 No.1
The PVC insulated flexible cords are used mainly as power supply cords of electric appliance. This electric wire is a stranded wire consisted of dozens of strands. In case stranded wires are disconnected by mechanical stress, it weakens electrically. Finally, the over current flows through stranded wires, and electrical fire occurs. In this study, we analyzed the melting properties of strands by over current, such as melting process, melting current and melting time. And we analyzed that quantity of heat for melting, a cross sectional structure, and surface structure by optical microscope and SEM. As analysis results, melting time decreased as melting current increased. And quantity of heat for melting was low, too. From the cross sectional structure of melted wire, when a melting current low and melting time long, it was found that the dendrite structure grew. However, the dendrite structure is hard to grow because growing time is not enough when a melting current high and melting time short.
High efficient rice transformation method by modifying co-cultivation conditions
Hyang-Mi Park,Yul-Ho Kim,Tae-Young Hwang,Chang In Yang,Ji Ung Jeung,Young Chan Cho,Kyoung Ho Kang,Chung-Kon Kim 한국육종학회 2012 한국육종학회 심포지엄 Vol.2012 No.07
Rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5㎎/ℓ L-cysteine, 1mM sodium thiosulfate, 1mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5㎎/ℓ silver nitrate). Co-cultivation temperature (23. 5℃ for 1 day, 26.5℃ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.
옥외용 LED 가로등 및 보안등의 전력변환방식에 따른 출력 특성 분석
김향곤(Hyang-Kon Kim),김동욱(Dong-Ook Kim),김동우(Dong-Woo Kim),문현욱(Hyun-Wook Moon),최효상(Hyo-Sang Choi) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.4
본 연구에서는 LED 가로등 및 보안등의 전력변환장치(컨버터)의 구성에 따른 전기적 특성을 비교, 분석하였다. 실험결과, 별도의 외합을 갖는 외장형 컨버터의 출력특성이 양호한 것을 알 수 있었다. 주로 조명등기구 내부에 일체형으로 부착되는 트로이달 코일과 전력전자소자의 조합 또는 소형트랜스, 콘덴서, 전력전자소자로 조합되는 전력변환장치의 경우, 1차측의 전압, 전류 파형에 왜곡이 있었으며, 2차측의 출력전압과 전류파형에 있어서도 영점을 갖는 반파나 톱니파형을 나타냄을 볼 수 있었다. 이러한 전기적 특성은 LED 조명설비의 깜빡거리는 현상과 역륜, 성능, 수명에도 영향을 줄 것이다. 따라서, LED 조명의 특성에 적합한 컨버터의 성능 향상을 위한 지속적인 기술개발이 요구된다.
金珦坤(Hyang-Kon Kim),崔忠錫(Chung-Seog Choi),金桐郁(Dong-Ook Kim),崔孝祥(Hyo-Sang Choi) 대한전기학회 2007 전기학회논문지 P Vol.56 No.1
This paper describes characteristics for copper oxide growth of polyvinyl chloride(PVC) insulated wires by series arc. In this experiment, 600 V IV wires were used, and characteristics of oxide growth and ignition process were analyzed in case load was 300 W, 460 Wand 600 W, respectively. In the result of experiment, covering materials were molten, carbonized and ignited, whereas, oxidized materials were grown in conducting material. During copper oxide was growing, contact voltages and power dissipations increased. When there is copper oxide growth, the waveform of current showed sinusoidal waveform, and the waveform of voltage showed modified waveform. Oxidized materials were heated at about 905 ℃. surface structure showed irregular shapes, and cross-section showed multiple cracks. And, the results of this experiment were applied to the fire cause analysis of fire evidence collected at the fire scene.
수중에서의 LED 조명용 DC 전로의 누전 특성에 관한 연구
김향곤(Hyang-Kon Kim),길형준(Hyoung-Jun Gil),김동우(Dong-Woo Kim),문현욱(Hyun-Wook Moon),최효상(Hyo-Sang Choi) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.11
본 연구에서는 LED 가로등 및 경관조명의 DC 전로가 수중에서 누전되었을 때의 전기적 특성과 LED 조명의 동작 특성에 대하여 실험, 분석하였다. 분석결과, 컨버터(전원공급장치)의 구조(절연형, 비절연형)에 따라 누전에 있어 전기적 특성에 차이가 있었다. 특히, 비절연형 컨버터의 경우, 수중에서의 누전에 의해 누설전류가 접지극을 통하여 흘렀으며, 컨버터의 출력전압의 크기에 따라 +극 또는 -극과 접지극(판)의 접촉시 수중에서 아크가 발생함을 확인할 수 있었다 교류를 직류로 변환하여 공급하는 DC 전로에서서의 감전사고 예방을 위하여 LED 조명에 사용되는 컨버터는 반드시 절연형의 것을 사용하는 것이 필요하다. 앞으로 DC 누전 이외의 단락, 접촉불량 등 전기적 이상에 대한 지속적인 연구와 기술 개발이 필요하다.
김향곤(Hyang-Kon Kim),길형준(Hyoung-Jun Gil),김동욱(Dong-Ook Kim),김동우(Dong-Woo Kim) 대한전기학회 2009 전기학회논문지 P Vol.58 No.4
In this paper, we studied insulation characteristics of LED lamps for load and street lighting. LED lamps can be divided into internal type and external type according to converter type. In this study, we analyzed technology standard, K(Electrical Appliances Safety Standards) and KS(Korean Industrial Standards) about insulation resistance for LED lamps for load and street lighting, and measured insulation resistances for each measured point. Mostly, insulation resistances were measured high more than regulation value but some measured points were measured badly. We expect that the results of these experiments would be helpful for electrical safety of LED lighting installation, manufacture, construction and maintenance.
LED 조명설비의 컨버터의 DC 누전에 따른 전기적 특성 분석
김향곤(Hyang-Kon Kim),김동우(Dong-Woo Kim),이기연(Ki-Yeon Lee),문현욱(Hyun-Wook Moon),최효상(Hyo-Sang Choi) 대한전기학회 2010 대한전기학회 학술대회 논문집 Vol.2010 No.7
본 논문에서는 LED 조명설비의 전원공급에 사용되는 컨버터의 DC 누전에 따른 전기적 특성에 대하여 실험, 분석하였다. 컨버터는 교류의 전원을 입력받아 저전압의 직류 전원으로 변환시키는 장치로컨버터 2차측의 출력단 즉, +극 또는 -극과 LED 모듈로 이어지는 전로에 절연불량으로 누전이 발생하였을 때 컨버터 1차측의 전원단에 설치된 인체감전보호용 누전차단기의 동작특성과 함께, 컨버터 1차측 및 2차측 단자와 접지극간의 전압, 전류 특성에 대하여 측정, 분석하였다. 측정결과, 비절연형 컨버터에 있어 1차측의 입력전원에 따라 동일한 측정점간의 전압값에 차이를 나타냈으며, 특히, 중성선이 연결된 상태에서 2차측 +극과 접지극 사이에 컨버터의 출력전압이 그대로 나타남을 알 수 있었다. 또한, 컨버터 2차측의 +극과 -극을 각각 대지에서 인출한 접지극에 강제로 누전시켰을 때, 컨버터의 1차측에 설치된 인체감전보호용 누전차단기가 동작하지 않음을 알 수 있었다. 이는 기존의 누전차단기는 컨버터 2차측의 누전에 대한 보호를 하지 못함을 나타내는 것이여 감전사고의 예방을 위한 방안의 마련이 요구된다. 향후 다양한 조건에서의 지속적인 연구 결과는 DC 누전에 따른 감전사고 위험성 해석과 예방대책의 강구에 도움을 줄 것으로 기대된다.