변압기의 유동대전에 대한 유속 및 유온의 영향에 관한 연구

정원용,고희석,박상현,박재윤,김정달 慶南大學校 附設 工業技術硏究所 1992 硏究論文集 Vol.10 No.-

本 硏究에서는 固體-液體 界面에서 液體가 流動할 때 발생되는 유동대전에 대한 硏究로서 大容量 變壓器내에서 絶緣油가 통과하는 通路를 모델링한 帶電 파이프를 設計·製作하고 대전 파이프내의 油路形狀에 따른 流動電流를 側定·分析하였다. 이러한 實驗으로부터 얻은 결과는 다음과 같다. 1) 流動電流는 油速의 增加에 따라 線形的으로 增加하였으며, 油溫의 增加에 따라 약 46[℃]이하에서는 增加하고 그 이상에서는 感少한다. 2) 絶緣油의 흐름이 원활하게 되도록 油路形狀을 변화시키면 流動電流는 感少한다. In this paper, the streaming electrification generated at a solid-liquid interface is studied. Electrification pipe modeled on the oil path of the high power transformer is designed and manufactured. The Streaming current is measured as a function of oil velosity, temperature at each electrification pipe. From the result of this study the following conclusions are obtained. 1) The streaming current increases linearly with increasing of oil velocity and It increases at lower temperature than 46[℃]and decreases at higher temperature than 46[℃] 2) The smoother the flow of insulating oil is the less the streaming current decreases.

생쥐 중이와 상기도 점막의 섬모세포운동

정하원,오승하,유원석,이강수,모지훈,전상준,김인상,김종선 대한이비인후과학회 1999 대한이비인후과학회지 두경부외과학 Vol.42 No.9

우라늄 이온의 선택흡착

정종헌,김준수,오원진,유재형,유승곤 한국공업화학회 2002 응용화학 Vol.6 No.1

Uranium-containing aqueous wastes have been treated by electrosorption on a carbon electrode composed of activated carbon fibers(ACFs) in a continuous flow-through cell. Effective uranium (VI) removal is accomplished when a negative potential in the range of -0.3 to -0.9V (vs. Ag/AgCI) is applied to the carbon electrode. For a feed concentration of 350mg/l, the concentration of U(VI) in the cell effluent is reduced to less than lmg/l. Electrosorption capacity over 552 mg_uranium/g_ACF is reached.

흡착 우라늄 이온의 전기 탈착거동

정종헌,원휘준,최왕규,김계남,이성호,오원진 한국공업화학회 2003 응용화학 Vol.7 No.1

Liquid wastes containing uranium ions in high concentration of chemical salts havebeen treated by electrosorption on a activated carbon fibers(ACFs) electrode. Effectiveuranium (VI) removal is accomplished when the potential is -0.5V(vs. Ag/AgCl) ormore negative. For a feed concentration of 100mg/1, the concentration of U(VI) in thecell effluent is reduced to less than 1mg/1, and electrosorption capacity over 500mg/uranium/gACF is reached. The adsorbed uranium can be desorbed up to 99%for 20h by passing a 1.9N NaCl solution at pH 3 through the cell and applying a potential of +1.2V. The amount of desorbed uranium increased as the solution pHwas lowered and the applied potential increased.

연질폴리우레탄폼의 물리적 성질 및 흡음율에 관한 연구

정종원,박남국,박선정,박종래,김영철 全南大學校 觸媒硏究所 1997 觸媒硏究 論文集 Vol.19 No.-

The effects of polyols, isocyanates. surfactants and water on the physical properties of the polyurethane foam were investigated. The resin used in this study was prepared from a variety of polyol mixtures by adding catalyst, surfactant and cross-linker. The polyurethane was foamed from the resin by adding an equivalent amount of isocyanate and was used in property measurements. The physical properties were more affected by the type of isocyanates and the amount of water than the sound absorption coefficient. The sound absorption coefficient of the polyurethane foam was superior for the polyol mixture of KE-810(40%)FA-733(40%)/FA-703(20%). The sound absorption coefficient was increased with the amount of surfactant L-5309 up to 3000Hz, but was decreased above that frequency.

餘暇活動 參加의 社會的 要件 : 椿川市內 主婦들을 中心으로 Like above results based on researches about social in women's leisure activity in Chunchon city can be derived

鄭淸子,夫基源,朴南煥 江原大學校附設 體育科學硏究所 1984 江原大學校附設體育科學硏究所論文集 Vol.- No.9

S. E. S. is one of the elements in resolving participation for individual leisure activities and is static leisure activity rather than dynamic activity. It is probable that that women try to participate in leisure activity dynamically, their husbands, however, have initiative in women's activities. However, it is certain that social elements in the step from family of orientation to family of procreation cannot be found apparently. This(research) remains a few questionable problems. One of them is to explain several elements except for choice of leisure activities and effective factors in participation in leisure activity; resolving participation in activities not only for women but all of the members in family.

생체내 심근허혈-재관류 모델에서 멜라토닌의 재관류 부정맥에 대한 심근보호작용에 관한 연구

조규종,김원,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Recently, a few studies demonstrated that melatonin reduced the severity of myocardial reperfusion injuries, such as reperfusion arrhythmias. However, it is uncertain whether the melatonin reduces reperfusion arrhythmias in thus anesthetized animals because results were obtained using isolated hearts. Thus, to see whether melatonin reduces reperfusion arrhythmias in anesthetized animals, we examined the effect of melatonin on the incidence of reperfusion arrhythmias in an anesthetized-cat model of regional ischemia. Method: Adult mongrel male cats(n=30, 2.9∼4.2 kg) were anesthetized under positive-pressure artificial ventilation with room air. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in experimental group(n=15) were divided into two. Group I(n=6) was pretreated with melatonin, 1 mg/kg, before occluding the LAD. Group II(n=9) was pretreated with melatonin, 10 mg/kg. The animals in experimental group were subjected to ischemia/reperfusion insult following drug treatment: melatonin was applied intra-peritoneally for 3 minutes just before LAD coronary artery ligation. The Fisher's exact test was used to compare the data from different animal groups. p<0.05 was considered significant. Results: The incidence of ventricular fibrillation(VF) during the reperfusion phase in group II(pretreated with melatonin, 10 mg) was significantly smaller than that in the control group(p-value = 0.0029). However, no statistically significant difference of VF incidence was found between group I(pretreated with melatonin, 1 mg) and the control group. Conclusion: Employing an anesthetized-cat model of regional cardiac ischemia, we investigated the dose-dependant effects of melatonin on reperfusion-induced arrhythmia. The cats pretreated with 10 mg/kg of melatonin before ischemia had a significantly reduced incidence of lethal reperfusion-induced arrhythmia, but there was no difference between the cats pretreated with 1 mg/kg of melatonin before ischemia and the control group.

동시공학 설계 개념을 이용한 자동차 현가 장치의 최적 설계

김정욱,전용범,이종원 중앙대학교 미래신기술연구소 2002 미래신기술연구소 논문집 Vol.11 No.2

동시동학 설계 방법은 보다 짧은 개발기간과 저렴한 생산비용으로 보다 우수한 품질을 갖는 제품의 개발을 위해 적용될 수 있다. 본 논문에서는 이러한 동시공학 설계개념을 이용하여 자동차 현가 장치의 최적 설계에 대한 연구를 수행하였다. 본 논문에서 제안한 동시공학 설계 개념을 이용한 자동차 현가 장치의 최적 설계 과정은 전처리 설계 단계, 해석 단계, 후처리 단계로 구성된다. 또한 본 논문에서는 현재 독립식 현가 장치 중에서도 전륜 현가 장치로 널리 쓰이고 있는 맥퍼슨 스트럿 현가 장치에 대해 기구학적 민감도 해석과 함계 이를 통한 최적 설계를 수행함으로써 최초 현가장치를 설계 시, 레이아웃(layout) 결정에 유용하게 적용될 수 있는 새로운 접근법을 제시한다. Concurrent engineering design methods can be applied to meet the demand for the quality product with lower production cost and time. In this paper, the optimal design of the automotive suspension system using concurrent engineering design concept is studied. The optimal design process of the automotive suspension system is composed of a pre-processing design stage, and analysis stage and a post-processing stage. In this paper, optimal design with kinematic sensitivity analysis for a McPherson strut suspension system which is widely used for a from wheel suspension is proposed and new approach method which can be applied usefully to determine the layout of suspension system is proposed when a engineer designs the suspension system at the first stage.

17β-Estradiol의 심근 보호작용에 대한 연구 ; 재관류 부정맥을 유발한 동물실험

홍정석,김원,조규종,이미우,장성은,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Although reperfusion certainly prevents tissue ischemia from possible cardiac death, several lines of evidence suggest that reperfusion may paradoxically aggravate the frequency of serious reperfusion-induced lethal arrhythmias. It has been reported that acute administration of estrogen at physiological concentrations reduced with myocardial ischemic injury in women with coronary heart disease. In studies with canines, acute administration by either the intra-muscular or the intra-coronary route similarly prevented ischemia and reperfusion dysrhythmias and also reduced the infarct size because the estrogen increased the distal coronary perfusion pressure, scavenged free radicals and had other effects during both ischemia and reperfusion. However, the canine heart is notoriously well collateralized. 17β-estradiol induces very little vasorelaxation in cat coronary rings, suggesting that increased ischemic myocardial blood flow dose not contribute to the protective effect. In the present study, employing a cat model of regional cardiac ischemia, we examined whether reperfusion rendered after acute administration of 17β-estradiol could lower the incidence of reperfusion-induced lethal arrhythmia and the death rate. Method: Adult mongrel male cats(n=31, 2.7∼4.5 kg) were anesthetized under positive-pressure artificial ventilation with room air. Electrocardiograms were recorded. The animals of the control group(n=15) were subjected to 20-minute left anterior descending coronary artery(LAD) occlusion followed by abrupt reperfusion. The animals in the experimental 17β-estradiol(2 or 20 ㎍/kg) group were subjected to ischemia/reperfusion insult following drug treatment: 17 β -estradiol was applied intravenously within the 60 seconds just before LAD ligation followed by abrupt reperfusion. The Fisher's exact test was used to compare the data from different animal groups(p<0.05). Results: The number of arrhythmias(ventricular premature beat, ventricular tachycardia and ventricular fibrillation) emerging during the reperfusion phase were not statistically different from that in the control group. The death rate in the 17β-estradiol 20㎍/kg group was lower from that in the control group(P value = 0.039). Conclusion: Acute administration of 17β -estradiol at a supraphysiological concentration might produce cardioprotective effects, not by modificating the coronary blood flow into the threatened myocardial region, but by other mechanisms that directly or indirectly increase the intrinsic myocardial ischemic tolerance in the cat during the reperfusion phase.

범하수체 기능저하증을 동반한 일차성 중추성 림프종의 1예

김원영,김원,조규종,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

A primary central nervous system lymphoma(PCNSL) is defined as a lymphoma limited to the cranial-spinal axis without systemic involvement. PCNSLs were formerly very rare, only 0.5∼ 1.2% of all intracranial neoplasms, and were usually associated with acquired immuno-deficiency syndrome(AIDS) and other immune-compromised states. Recently, there has been a clear rise in the incidence of this disease among normal individuals. We describe a 77-year-old female with hyponatremia who presented with a confused mental state. Computed tomography(CT) of the brain demonstrated a suprasellar mass with enhancement. We evaluated the basic hormonal studies and the magnetic resonance imaging(MRI). A ventricular biopsy was done, and the result was a diffuse, large, B-cell-type malignant lymphoma. She presented panhypopituitarism and partial central diabetes insipidus. She received chemotheraphy and was discharged in an improved condition. We report a case of panhypopituitarism due to PCNSL and give a review of the literature.