AC 220V 부하전류 2 A가 흐를 때 발생되는 직렬 아크방전의 스펙트라 패턴 해석에 관한 연구

임종민(Jong-Min Lim),최충석(Chung-Seog Choi) 한국화재소방학회 2023 한국화재소방학회 학술대회 논문집 Vol.2023 No.1

형광등용 안정기의 화재원인 판정에 관한 연구

최충석,백동현 한국화재소방학회 2000 한국화재소방학회논문지 Vol.14 No.3

본 연구에서는 옥내 조명으로 널리 사용되고 있는 형광등용 안정기의 화재위험성을 분석하였다. 안정기 권선을 실체현미경으로 분석한 결과 용융흔을 다수 발견할 수 있었으나, 육안으로 원인 판정은 불가하였다. 700℃ 이상에서 열열화(熱劣化)된 안정기 권선은 연신구조(elongation structure)가 없어지고 구리입자의 확대된 형태만 보였다. 단락 권선의 금속현미경 분석에서 경계면을 중심으로 주상조직 및 보이드 성장의 규칙성이 확인된 것으로 보아 전기적인 단락이 층간에 일어났음이 증명되었다. SEM을 이용한 미세구조 분석에서 용융된 부분이 확인되었다. EDX를 이용한 스펙트라 분석에서 Cu의 구성요소인 CuL 및 CuK lines뿐만 아니라 OK line이 고르게 관측되고 있다. 이것은 재결합 과정에서 산소가 반응에 참여했음을 의미한다. In this paper, we analyzed the fire hazard of the ballast for fluorescent lamp used as the indoor lighting. In the result of being analyzed the ballast wire by stereo microscope, many melting points were discovered, it was impossible to judge a cause with the naked eye. In the thermal-deteriorated ballast wire, elongation structure disappeared at above 700℃, and it only showed the enlarged appearance of the copper particle. On the metallurgical microscope of short wire, as it was confirmed the regulation of the columnar structure and the void growth at the center of boundary-face, we found that electrical short-circuit generated. Also, it was confirmed the melted part on the analysis using SEM(scanning electron microscope). Not only CuL and Cuk line that is composition factor of copper but also OK line was observed uniformly on the spectra analysis using EDX(energy dispersive x-ray spectroscopy). It means that oxygen took part in reaction at the recombination process.

VCTFK의 반복피로에 의한 소손 패턴의 특성 해석

최충석,송길목,김동우 한국안전학회 2004 한국안전학회지 Vol.19 No.4

In this paper, we analyzed on the characteristics of the stranded wire disconnected by repeated stress. The stranded wires that were used in the experiment are PVC insulated flexible cords(VCTFK: Vinyl Insulated Vinyl Cabtyrc Cord Flat-type) of 0.75mm², 1.25mm², and 2.Omm². They are used to connect the load in low voltage. The stranded wires disconnected by repeated stress were magnified with optical microscope. Using X-ray, the disconnected wire were photo-graphed. we compared mechanical characteristics of the stranded wire between disconnected tendency and allowable current. On the mechanical strength of vinyl cap tire ellipse type cords under bending stress, VCTFK of 1.25mm²was the strongest of them. When it was bent 826.3±7 times, it appeared the disconnected tendency that element wires of VCTFK of 1.25mm²are more about 1.67 times than element wires of VCTFK of 0.75mm². In mechanical strength, VCTFK of 1.25mm² is higher about 1.7 times than VCTFK of 0.75mm². Therefore, we found out that mechanical strength was higher, when the wire had a lot of element wires. In comparison with bending stress, VCTFK of 1.25mm²is the strongest among samples, and it is the most useful in wires of movable type.

원발성 다한증의 교감신경차단술에 대한 임상적 고찰

정민규,이석기,임진수,최형호 朝鮮大學校 附設 醫學硏究所 2004 The Medical Journal of Chosun University Vol.29 No.1

Background : Exccssive sweating of the facial, Palms, axilla and soles, is a psychologically and occupationally distressing and sometimes disabling condition. VideoUassisted thoracoscopic surgery (VATS) is now mostly performed for treating of the facial, palmar and axillary hyperhidorsis. This study was designed to evaluate the results and complication of sympathicotomy of the primary hyperhidrosis. Material and methods : From June 1999 to May 2002, 55 patients ( 30 males and 25 females ) suffering from primary hyperhidirosis were operated. The mean age of patients was 24.0±6.0 years. Bilateral thoracoscopic sympathicotomy was resected the only T2, T2 & T3, onlY T3, T3 & T4 and T2, T3 & T4. The mean follow up period was 18±6.5 months. Results : Mean operation time was 61.2+25.0 minutes and the mean elevation of palmar temperature after sympathicotomy was 1.13±0.2℃. There were no operative deaths but some complication existed : 42 patients (76%) complained the compensatory hyperhidrosis, and 5 patients was developed the postoperative pneumothorax. Sweating decreased in 43% of the planter hyperhidrosis. Conclusion : Most of the patients were satisfied with the postoperative results of the thoracoscopic sympathicotoiny. We conclude that thoracoscopic sympathicotomy is a simple, safe and effective technique in primary hvPcrhidrosis, but satisfaction has been decreased by the compensatory hyperhidrosis; therefore, it is important to thoroughly explain the compensatory sweating. We recommend that the less extent of sympathicotomy decrease the incidence of compensatory hyperhidrosis.

누전차단기 외함 전원측 단자사이의 트래킹에 의한 탄화특성 분석

최충석,송길목,김동우 한국화재소방학회 2003 한국화재소방학회논문지 Vol.17 No.4

본 논문은 누전차단기 외함 전원측 단자사이에서 발생하는 전기화재 원인에 대한 분석을 연구하였다. 누전차단기는 보호범위의 전기시설물에서 누전 또는 과부하에 의한 차단을 목적으로 한다. 누전차단기의 전원측 단자는 트래킹에 의해 화재로 쉽게 이어질 수 있다. 따라서, 누전차단기의 재현실험을 통해 트래킹시료(E₁)와 화재현장에서 트래킹된 것(S₁)을 비교분석하여 전기화재의 원인을 밝히는데 중요한 자료가 되도록 하였다. 실험은 IBC Publ. 112법을 응용하여 실시하였고 누전차단기에서 미소방전과 건조대가 발생한 후 소손되는 것을 확인하였다. E₁센서 전원측 단자간의 절연저항은 약 25.7Ω이고 S₁ 절연저항은약 58.6Ω이었다. E₁의 발열피크는 491.0℃ 603.2℃였다. 603.2℃에서의 발열피크는 트래킹에 기한 것이다. S₁의 발열피크는 593.1℃에서 나타났다. 트래킹에 의해 변화된 시료는 IR 흡수스펙트림에서 1590 cm-¹ 서 흡광피크가 나타나지 않았다. In this paper, we studied on the characteristics of RCD(Residual Current Device) case deteriorated by tracking, and compared the tracked samples between in the site of fire(S₁) and in the reappearance experiment(E₁). This experiment is applied to IEC Publ. 112 method. Electrical fire by tracking occurred after scintillation and dry-band generated. The insulation resistance between source terminals of RCD case was about 25.7 Ω in E₁ and the resistance was about 58.6 Ω in S₁. The exothermic peaks of E₁ appeared at 491.0℃ and 603.2℃. The exothermic peak at 603.2℃ was shown by tracking. And the exothermic peak of S₁ appeared at 593.1℃. In spectrum of S₁ and E₁, absorption peak didn't appear at near 1590 cm¹.

열적 스트레스 변화에 따른 600V 비닐절연전선의 특성 분석

최충석 한국화재소방학회 2001 한국화재소방학회논문지 Vol.15 No.1

본 연구에서는 660V 비닐절연전선에 열적 스트레스를 인가하였을 때 전선의 특성 변화를 분석하였다. 전선의 구조 분석에서 정상 전선은 표면에 방향성을 갖고 있으나, 400℃ 이상에서 열화된 전선의 경우 탄화물, 크랙, 결정 등이 형성되었다. 정상 전선의 표면 조성은 Cu ;100%였으나, 800℃에서 열화된 전선의 단면 조성은 Cu ; 78.89%, O ; 21.11%를 나타냈다. 연동선의 시차주사열량 분석 결과 700℃ 이상에서 열화된 전선에서 새로운 반응 피크가 관측되었다. 절연물의 시차열 분석에서 150℃로 열화된 전선의 경우 정상 전선의 반응점보다 낮은 264℃에서 흡열 반응이 나타났다. 동선의 열화에 따른 산소 점유율은 500℃에서 약 20%이다. In this paper, we analyzed the properties change of electric wire when the thermal stress was applied to 600V grade polyvinyl chloride insulated wire (IV). In the structure analysis, normal wire has the properties of direction on the surface, but in case of deteriorated wire at above 400℃, it formed the carbide, the crack and the crystal. The surface composition rate of normal wire was Cu ; 100%, but the section composition of the deteriorated wire at 800℃ showed Cu ; 78.89%, O ; 21.11%. In result of analyzing the differential scanning calory of copper wire, the new reaction peak was observed on the deteriorated wire at above 700℃. In case of the deteriorated wire as 150℃ at the differential thermal analysis, an endothermic reaction appeared at 264℃ lower than the reactive point of normal wire. The occupation rate of oxygen according to the deterioration of copper wire is about 20% at 500℃.

과전류에 의해 용단된 소선의 특성해석에 관한 연구

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.

마우스 Myeloma Cell P3-X63-Ag8.653 및 T Cell Hybridome DO11.10에서의 Programmed Cell Death 유발 특성 비교

임석원,정용훈,최용,한승룡,조양자 한양대학교 의과대학 1998 한양의대 학술지 Vol.18 No.2

This study was aimed to prove that the death of HGPRT myeloma V653 by aminopterin treatment is due to PCD. This PCD was also compared with a relatively well-defined dexamethasone-induced PCD of T-cell hybridoma DO11.10. And these PCD systems were further characterized by inhibiting protein synthesis with cycloheximide, inhibiting mRNA synthesis with actinomycin-D, increasing intracellular calcium with calcium ionophore A23187. Induction of c-myc, an universal apoptosis gene, was also compared between these 2 systems. Viability of V653 cell was decreased by aminopterin-treatment in a dose-dependent manner. After treatment of aminopterin, this decrease of viability began in 6 hours and was accelerated in 12-18 hours. DNA fragmentation of V653 was detectable at 3 hours of incubation and peaked in 12-18 hours. Patterns of decrease in cell viability and increase in DNA fragmentation of dexamethasone-treated DO11.10 cells was similar to that of aminopterin-treated V653 cell, but the progress was much slower. The decrease in cell viability and increase in DNA fragmentation of aminopterin-treated V653 cells were inhibited by protein synthesis inhibitor cycloheximide, and RNA synthesis inhibitor actinomycin-D. In contrast the decrease in cell viability and increase in DNA fragmentation of dexamethasone-treated DO11.10 cell were accelerated by cycloheximide and actinomycin-D additions. Ca^2+ ionophore A23187 addition to aminopterin-treated V653 cells and dexamethasone-treated DO11.10 accelerated the decrease in cell viability and the increase in DNA fragmentation of both cells. In northern blot analysis, induction of c-myc gene was observed in aminopterin-treated V653 cell reached peak at 2hours and thern decreased drastically. Induction of c-myc gene in dexamethasone-treated DO11.10 cells was much slower and the fold of gene induction was much lower than that of aminopterin-treated V653 cell. Ultrastructural changes during the death process were observed by using electron microscope. Dilatation of rough endoplasmic reticulum(RER) and detachment of ribosomes were the earliest ultrastructural changes, which were observed in 30 minutes after death induction. The results of this study suggest that aminopterin-induced selective elimination of fusion partner V653 myeloma cell is due to PCD, and that this process requires de novo protein and RNA synthesis in which a Ca^2+ -mediated signal transduction pathway is involved.

Pt-Co 합금박막형 측온저항체 온도센서의 제작과 그 특성

홍석우,최영규,정귀상 경북대학교 센서기술연구소 1998 센서技術學術大會論文集 Vol.9 No.1

We made Pt-Co alloy resistance patterns on the Al_(2)O_(3) substrates by lift-off method and investigated the physical and electrical characteristics of these films under various conditions (the input power, working vacuum, annealing temperature, thickness of thin films) and also after annealing these films. The TCR value of Pt-Co alloy thin films was measured with various thickness of thin films and annealing conditions. The optimum TCR value is gained under conditions 3000Å of thin films thickness and 1000°C of annealing temperature. These results indicate that Pt-Co alloy thin films have potentiality for the high resolution RTD temperature sensors.

A Study on the Growing Properties of Cu2O according to the Change of Load

Choi,Chung Seog,Kim,Dong Ook,Kim,Hyang Kon 한국산업안전학회 2001 한국안전학회지 Vol.16 No.5

Being the joining badness of the wire, the hot zone was generated, and it was necessary to maintain the proper current for the growing of continuous copper oxide. We could found the fact that the voltage drop was enlarged and the resistance was increased as the hot zone was grown. In analysis on SEM image at the surface of the hot zone, the original structure of the wire disappeared and particles of the irregular type showed the laminated form. In the result of analyzing into EDX, its surface component was Cu; 84.02%, O; 12.28%, C; 3.70%, and its cross section was Cu; 87.94%, O; 12.06%. In analysis of DSC, the wire generated by the joining badness showed the calorievariation at 1,231℃, and it was found that the produced oxide was Cu₂O.