복강경을 이용한 대장 부분 절제 시행 1예

박재갑,서경석,정회원,김선회,오용석,송인성,박용현 대한대장항문학회 1993 Annals of Coloproctolgy Vol.9 No.1

Nortriptyline 제제의 생물학적 동등성에 관한 연구

신재국,차인준,장인진,정원석,김용식,박찬웅,신상구 大韓臨床藥理學會 1993 臨床藥理學會誌 Vol.1 No.1

고관절 전치환술시 응용프로그램을 이용한 수술 전 계획

원중희,김용민,최의성,손현철,박경진,남기세,정재중 대한고관절학회 2003 Hip and Pelvis Vol.15 No.3

對稱 二重 表面缺陷의 疲勞龜裂成長擧動에 對한 硏究

崔鎔湜,金在元 成均館大學校 科學技術硏究所 1988 論文集 Vol.39 No.1

This paper is concerned with the fatigue crack growth behavior for twin surface cracks. PMMA was selected for the specimen material because PMMA is transparent and the crack length of thickness direction can be measured exactly. Tension specimens having twin circular arc-shaped notch were used in the testing process. The results obtained from a series of experiments are summarized as follows: 1. The fatigue crack propagation of shallow-type surfacs cracks such as the case of crack aspect ratrio c/a = 0.151 initiated at the deepest point of the crack. Therefore, stress intensity factor at this point is estimated to be maximum value. 2. The fatigue crack growth race of the width direction was larger than that of the thickness direction. 3. The interaction behavior between two surface cracks was obseved in the fatigue crack growth rates toward the thickness direction as well as in those in the width direction, particularly, in the latter was greater than in the former. The more surface crack-tips approache closely, the greater the fatigue crack growth rate increases rapidly by the crack-tip interaction effect. 4. During the stable fatigue cracks are propagating, two surface cracks keep the feature approximately semi-elliptical cracks having major axis to minor axis length ratio of 3/2.

단독표면균열재의 피로수명 예측 해석

최용식,양원호,김영진,김재원 成均館大學校 科學技術硏究所 1990 論文集 Vol.41 No.1

Recent studies have shown that the fatigue growth behavior of semi-elliptical surface crack cannot be adequately predicted solely by the stress intensity factor analysis. The variation in constraint along the crack border, from plane stress condition at the plate surface to plane strain condition at the point of maximum crack depth, must be an important factor affecting the fatigue crack growth behavior. In this paper, an analysis on the fatigue life prediction of a semi-elliptical surface cracked body was performed, accounting for the variation in constraint along the crack border. That is, the fatigue life for a surface cracked body was predicted using linear elastic fracture mechanics concepts that were modified to account for crack closure behavior. The model for the fatigue life prediction in consideration of crack closure phenomenon was developed, and then the predicted fatigue lives using the model were compared with test data from PMMA specimens. The predicted results appeared to be conservative.

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.

Oxalate와 Enrofloxacin투여한 랫트신장에 대한 병리조직학적관찰

오원석,이차수,오규실,정원일,정재용,정다히,정규식 한국임상수의학회 2003 한국임상수의학회지 Vol.20 No.4

To investigate the renal effects of enrofloxacin administration on rats induced with dehydration or hyperoxaluria, male rats were treated with enrofloxacin of 50 mg to 500 mg/kg b.w.. The microscopical observations of kidney and urine sediment were carried out in the experimental groups. The result obtained were as follows; The male rats deprived of water for 72 hours and administered with enrofloxacin. As enrofloxacin administration dose was increased, clinical signs such as loss of appetite, depression, weakness, and loss of urine output became more severe. In the histopathological findings, there were hyperemia and hemorrhage in renal cortex, vacuolation and necrosis of renal tubular epithelia, proteinous casts within renal tubules. The male rats were orally administered with sodium oxalate and injected with enrofloxacin for 7days. As enrofloxacin administration dose was increased, clinical signs such as the loss of appetite and water consumption, and weakness became more severe. In the histopathological findings, there are hemorrhage of glomeruli and cortical hyperemia, vacuolation and necrosis of tubular epithelia, proteinous casts in renal tubules. In the microscopical findings of urine sediment, there are calcium oxalate crystal (diamond-like type) and magnesium ammonium phosphate crystals (rhomboid). The male rats were intraperitoneally injected with sodium oxalate and administered with enrofloxacin for 7days. As enrofloxacin administration dose was increased, clinical signs such as the loss of appetite and water consumption, weakness were more severe. In the histopathological findings, there were hyperemia and hemorrhage in both glomeruli and renal cortex. Severe necrosis of renal tubular epithelia, bluish materials within renal tubules were also found. In the microscopical findings of urine sediment, there were many calcium oxalate crystals. The present results suggest that enrofloxacin has some injurious effects in rats having dehydration or hyperoxaluria, and clinically, we should consider these renal injury effects when we use enrofloxacin in patients accompanied renal disease, dehydration and hyperoxaluria conditions.

증후성 단일 소심부뇌경색의 임상적 및 방사선학적 양상

신원철,이태규,노용우,오재욱,장대일,정경천 대한노인병학회 2000 Annals of geriatric medicine and research Vol.4 No.3

濕式法에 依한 輝安鑛으로부터 三酸化 안티모니의 製造에 關하여

오재현,김준수,고인용,정원용 연세대학교 산업기술연구소 1979 논문집 Vol.11 No.1

An investigation on the production of high purity Sb₂O₃was carried out by means of the acid leaching process from the roasted ore of stibnite. The approach of these studies has been to investigate purity, particle size, recovery and crystal structure of Sb₂O₃obtained through the subsequent treatments of leaching, hydrolysis and neutralization under various conditions. The results obtained in these experiments are summarized as follows; 1) It was possible to use dilute hydrochloric acid to extract Sb₂O₃from the roasted stibnite. Because of the prior roasting treatment, the contamination of impurities could also be reduced in the final products. 2) The rate of extraction of Sb₂O₃from the roasted stibnite was increased concentration of hydro-chloric acid as increased amount of addition of the acid. 3) The yield of Sb₂O₃obtained by hydrolysis of SbCl₃was increased with increasing temperature of hydrolysis. 4) The crystal structure of Sb₂O₃obtained by hydrolysis of SbCl₃at 20℃(room temperature) was confirmed as a orthorhombic crystal structure which is the same as that of valentinite. The recovery of Sb₂O₃from the roasted ore appeared to be nearly 100% under optimum conditions.

크리깅 기법을 이용한 마이크로 믹서의 최적 설계

박재용,김상락,이원구,유진식,김용대,한석영,맹주성 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

An active micro-mixer, which was composed of an oscillating micro-stirrer in the microchannel to provide rapid, effective mixing at high flow rates was analyzed. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight microchannel and microchannel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interactionafter the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced and stabilized. Therefore, an optimum design for a dynamic micro-mixer with an oscillating stirrer was performed using Kriging method in order to obtain a optimum solution. The design parameters were established as the frequency, the length and the angle of the stirrer, and the optimal values were determined to be 2.0932, 0.8D and ± 75°, respectively. It was found that the mixing index of the optimal design increased by 88.47% compared with that of the original design.