산화툴륨의 결함구조와 전기전도성에 대한 연구

최재시,정원양,김진호,이창환 연세대학교 자연과학연구소 1985 學術論文集 Vol.14 No.-

산화툴륨의 전기전도도를 400~1100℃의 온도영역과 10^-6~10^-1atm의 산소분압범위에서 측정하였다. 일정한 산소분압에서 전기전도도의 대수값을 절대온도의 역수에 대하여 도시한결과 직선관계를 얻었으며 inflection point가 나타났다. 활성화에너지는 고온영역에서 34.5kcal/mole, 저온영역에서 19.3kcal/mole이었다. 전기전도도의 산소분압의존성은 직선관계를 나타내었으며 600~1100℃의 온도영역에서 σ∝Po_2^1/5.3, 400~600℃의 온도영역에서σ∝Po_2^1/6.3이었다. 고온영역에서의 주결함은 V_??이며, 저온영역에서는 O_?? 임이 밝혀졌다. 전도도의 온도 및 산소분압의존성을 해석하였으며, 전도메카니즘을 제시하였다. The electrical conductivity of thulium sesquioxide has been measured from 400 to 1100℃ under oxygen partial pressure (Po_2) of 10^-6 to 10^-1 atm. Plots of log conductivity vs. 1/T at constant Po_2 are found to be linear with inflection point and the activation energies obtained from the slopes are 34.5kcal/mole in the higher temperature region and 19.3kcal/mole in the lower temperature region. The Po_2 dependences of the electrical conductivity are found to be linear and closely approximated by σ∝Po_2^1/5.3 in the temperature range of 600-1100℃ and σ∝Po_2^1/6.3 in the range of 400-600℃. The dominant defect is V_?? in the higher temperature region and O_?? in the lower temperature region. The interpretations of conductivity dependences on temperature and Po_2 are presented and conduction mechanisms are suggested to illustrate the data.

중추에서 Prostaglandin계가 Renin-angiotensin System에 미치는 영향

최영태,김종승,문성호,오형균,김재훈,전제열,염철호,윤평진 朝鮮大學校 附設 醫學硏究所 1997 The Medical Journal of Chosun University Vol.22 No.1

Role of prostaglandins on the renin-angiotensin system in the central nervous system was examined in normotensive and 2-kidney, 1 clip (2K1C) hypertensive rats. The experiment was done under thiopental (50 ㎎/㎏, IP) anesthesia. Captopril and indomethacin were injected into the right lateral cerebral ventricle. Arterial blood pressure and heart rate were recorded from the femoral artery. Intracerebroventricular (ICV) captopril (1 ㎎) caused a decrease in mean arterial pressure in both normotensive and 2K1C hypertensive rats. The depressor response to captopril was more sensitive in hyper-tensive rats than in normotensive rats. Indomethacin treatment (ICV, 200 ㎎) altered the depressor response to captopril neither in normotensive nor in hypertensive rats. These results suggest that the cardiovascular effect of renin-angiotensin system in the central nervous system may not be mediated via prostaglandin systems in normotensive and 2KlC hypertensive rats.

回轉圓板의 應力擴大係數에 관한 硏究 : Stress Freezing Method of Photoelastic Experiment

최선호,이충섭,권재도,황재석 嶺南大學校 工業技術硏究所 1986 연구보고 Vol.14 No.2

It is well known fact that the stress distributions in the vicinity of crack tip and fracture problems are governed by stress intensity factor which is presented as a function of the crack shape, boundary condition and loading mode etc. In. the determination of the stress intensity factor, there are many theoritical and experimental methods. Among them the stress freezing method of photoelastic experiment has been considered to be one of the most accurate experimental methods which have been used for stress analysis. In this paper, this method was applied to the rotating disk with inner arbitrary crack. The results of photoelastic experiment for disk with various straight cracks, radial and others which are oblique to the radical direction were as follows. In case of radial crack, in comparison with the results of photoelastic experiment obtained by stress freezing method and the theoritical solutions of Blauel, stress freezing method is fully available for analysis of uniform dynamic status.

流路彎曲部 橋脚주위의 洗掘 및 保護工

宋在偶,李鎔桓,崔仁鎬 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

Laboratory flume experiments to investigate the characteristics of the flows and local scour around circular shapes of bridge pier in a curved channel are performed. This study examines the effect of a circular collar devices for controlling the depth of scour. The scour depth due to a collar is about 40% of the scour depth without collar in a straight course of the flume while it is about 44% of the scour depth without collar at the location of 150˚in a curved channel. when the collar is placed yd/h=-0.2 for which the diameter of a collar is twice of the pier diameter, reduction o scour depth is very effective in a straight channel but when the collar is placed at yd/h=-0.1, the reduction of scour depth is very effective in a curved channel.

鑄鐵熔接에 對한 一硏究 : on the practice of Cast Iron Repair Welding 鑄鐵補修熔接의 實際에 對하여

河載晧,崔圭夏 忠州大學校 1968 한국교통대학교 논문집 Vol.2 No.-

On the practice of Cast Iron Repair Welding in many cases, castiron like steel, the field of the use of castiron will be increadid. But castiron is difficatly welded because of many condition. As welding technic has been developing, the welding of cast iron is becoming the ofbect of study. The welding of cast iron requires such high technic that it is omitted especially in practice training for student, this point the purpose of this study lies in this point.

Kimura Disease 치험예보고 : 이하선 종양과의 감별 Pitfalls in Parotid Gland Surgery

류재현,정구용,한호성,최용만 梨花女子大學校 醫科大學 醫科學硏究所 1997 EMJ (Ewha medical journal) Vol.20 No.4

Kimura disease, which was initially described by Kimura et al. in 1948, is a rare entity that occurs primarily in Asian people characterized histopathologically by a lymphofolliculoid granuloma with infiltration of the mass and the surrounding tissue by eosinophils, often with concomitant peripheral blood eosinophilia and elevated serum Ig E. The kimura disease frequentlly involves head and neck region and reraly extrimities. When the disease involvews parotid gland, it is very difficult to differentiate clinically with parotid gland tumor. We have experienced a case of Kimura disease. The lesion was initially diagnosed as a parotid gland due to extensive fibrosis surrounding the mass. So, the mass excision was performed without clear identification of the facial nerve. The Kimura disease usually follows a benign course. But when this disease is confused with parotid gland tumor, there will be a danger of nerve injury due to difficulty in dissection of the extensive fibrotic soft tissue surrounding the parotid gland.

신동맥 협착 정도에 따른 도플러 초음파 소견

박재성,이혜경,김대호,최득린,권귀향,홍현숙,임한혁,김기정 순천향의학연구소 1995 Journal of Soonchunhyang Medical Science Vol.1 No.2

Renal artery stenosis is the one of causes of hypertension in a small percentage of all patients but is only anatomical cause that can be treated by means of surgery and percutanecous transluminal angioplasty. Angiography is the golden standard for diagnosis of renal artery stenosis, but a little invasive. With the advent of abdominal Doppler ultrasonography, renal artery stenosis could be diagnoed noninvasively. The experienced hands appears to be valuable in the doppler examination, ut some investigators consider it almost useless. The authors studied the effect of stenosis of renal artery on the downstream intrarenal blood flow, a snare was placed around renal artery in 12 rabbits and compressed to create stenosis while Doppler ultraonographic curve and flow index were obtained from main renal and interlobar arteries by means of placement of 10-MHz curved linear tranducer directly on the surface of kidney. The Doppler measurements were compared with the percentage of stenosis on angiograms. The results were as follow: 1. Ten satisfactory angiograms and Doppler ultrasonograms were obtained. 2. Three renal arteries were created stenosis below 70% (Group A), Seven were above 70% (Group B). 3. The ranges of RI (resistance index) were 0.61-0.86 (mean 0.78±0.154) at main renal arteries, 0.57-0.85 (mean 0.77±0.231) at interlobar artery. The range of PS (peak systolic velocity) were 13.1-28.8 (mean 21.65±4.445) m/sex at main renal artery, 5.2-18.1 (mean 11.74±4.095) m/sec at interlobar arteries. The RI of rabbits were higher than those of human (mean 0.58±0.05). 4. The range of RI in stenotic arteries of group B were 0.45-0.74 (mean 0.57±0.143) at main renal artery, 0.52-0.65 (mean 59±0.051) at interlobar arteries. The range of PS were 11.2-21.3 (mean 15.04±3.755) m/sec at main renal arte교, 5.7-11.3 (mean 8.24±2.056) at interlobar artery. The difference were statistical y significant (P=0.0302), but without remarkable change in group A. 5. Doppler ultrasonographic curve during progressive compression of renal artery showed dampened systolic waveform and diagonal upstroke at main renal arteries (71.4%) and interlobar arteries (85.7%) in group B, but without remarkable change in group A. 6. Release of the arterial compression caused higher than normal peak systolic velocity initially, at main renal arteries (42.9%) and interlobar arteries (28.6%). but the curve of all rabbits returned to normal within 5 minutes. The Doppler ultrasonographic index and curve were not changed on follow up Doppler ultrasonogram at 5 min. 10 min. 30 min. and 1 hour. The change of the systolic curves that compressed experimentally is identical to change in the pulsus tardus and parvus waveforms seen in both acute and chronic severe renal artery stenosis in humans, can helpul for the diagnosis of renal artery stenosis and the effects of treatment by percutaneous tranluminal angioplasty and surgery.

Epstein-Barr virus(EBV)와 연관된 Nasal type T/Natural Killer(NK)-cell lymphoma 1예

지두현,최지호,성경제,문기찬,고재경 울산대학교 의과대학 1996 울산의대학술지 Vol.5 No.1

Nasal type T/NK-cell lymphoma는 병리조직학적으로 응고성 괴사가 동반된 혈관중심성 침윤을 특징으로하며 T-cell과 NK-cell 항원을 모두 표현하는 면역조직화학염색 소견을 보이는 매우 드문 피부 림프종으로서 EBV와의 연관성이 흔히 보고되고있다. 저자들은 42세 여자에서 발생한, 전신적인 홍반성 구진, 판, 결절의 임상양상을 보였으며 피부 병변에서의 EBV-encoded RNA(EBER)에 대한 in situ hybridization상 양성소견을 보였고 전산화단층촬영, 골주사, 갈륨주사 등의 검사상 비강, 위장관 및 다른 내부장기 침범소견은 보이지 않아서 피부에만 국한된 경우로 사료되는 nasal type T/NK-cell lymphoma 1예를 보고하는 바이다.

Tufted Angioma와 유사한 소견을 보인 화농성 육아종

장경애,최정철,최지호,성경제,문기찬,고재경 대한피부과학회 1999 대한피부과학회지 Vol.37 No.6

Tufted angiomas are rare slowly progressive vascular lesions found typically in children and young adults, usually involving the trunk and neck. Microscopically, groups of capillary tufts, many uncanalized, were found dispersed at various levels in the dermis. Some authors regarded tufted angioma as a member of lobular capillary hemangiomas. We describe a pyogenic granuloma mimicking acquired tufted angioma on the lip in a 59-year-old woman. We suggest that a term lobular capillary hemangioma$quot; may be preferable in this case.

Ortho-Chlorobenzylidene Malononitrile(CS) 이 흰쥐 피부조직에 미치는 조직학적 영향에 관한 연구

이우용,최봉근,김잉곤,엄기일,정호삼,정호삼,류재만 한양대학교 의과대학 1998 한양의대 학술지 Vol.18 No.1

This study was undertaken to describe the fine structural changes of cytoplasmic organelles in epidermal cells, and the changes of volume and localization of collagen type Ⅰ in the dermis of rat skin by CS(Ortho-chlorobenzylidene malononitrile) application. The experimental animals, 100∼150gm of body weight rats(Sprague-Dawley strain), were sacrificed at 12 hours, 24 hours, 3 day and 5 day after CS application on the hair-shaved back skin. The specimens were prepared for ultrastructural findings, ultrathin sections were stained with uranyl acetate and lead citrate double stain and observed with Hitachi-600 electron microscrope. The others were incubated with rabbit anti rat type Ⅰ collagen antibody as primary antibody, and Goat anti rabbit IgG antibodies as secondary antibody And advidin-biotin-conjugated(ABC) peroxidase procedure was used. All of specimens for immune reactions were observed with light microscope. The results obtained were as follows. 1 Keratinocytes appeared fully necrotized after 3 days of CS application. The epidermis showed degeneration of basal lamina, enlargement of intercellular spaces and necrotic keratinocytes with vacuole and vesicles. And large keratohyalin granules were seen in the shrunken epidermal cells. 2 At 3 or 5 day after CS treatment, the normal cytoplasmic organelles of keratinocytes began to appear on the basal and prickel cells. 3 At 12 hour an 24 hour after CS treatment. The immune reaction of type Ⅰ collagen showed weak reaction in reticular layer of dermis. But at 3 day and 5 day after CS treatment, moderate immune reaction were seen in throughout the dermis. These results suggest that CS application to rak skin may induce changes of keratinocytes and reductive changes of type Ⅰ collagen in the dermis.