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검색결과 585,658건 처리시간 0.226초

Ethyl Silicate로부터 Silicon Nitride의 합성(I) (Synthesis of Silicon Nitride from Ethyl Silicate(I))

  • 오일환;박금철
    • 한국세라믹학회지
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    • 제25권4호
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    • pp.415-423
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    • 1988
  • Mixtures of carbon and silica (about 0.46${\mu}{\textrm}{m}$) which was synthesized by the hydrolysis of ethyl silicate, the molar ratio of silica/carbon was fixed as 1/10(weight ratio : 1/2), were nitrided in the temperature range 135$0^{\circ}C$~150$0^{\circ}C$. The phse of the product Si3N4 was $\alpha$ phase and the morphology was hexagnoal prism and the nitridation reaction was completed in 5 hrs at 150$0^{\circ}C$ or 7hrs at 145$0^{\circ}C$. The reaction rate above 150$0^{\circ}C$ was diffusion-controlled, following Jander equation. Activation energy Q was derived from the Arrhenius plot and the value was about 101kcal/mol. Axis ratio of Lattice constants(c/a) was 0.726 and unit volume was $\AA$3, the larger the molar ratio of carbon/Alkoxide was, the smaller the particle size of $\alpha$Si3N4 was.

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늑막직하 농양을 동반한 결핵성 간장 육아종 1례 치험 (Hepatic Tuberculous Granuloma with Subphrenic Abscess - A Case Report -)

  • 정상조;안재호;오성태
    • Journal of Chest Surgery
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    • 제24권6호
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    • pp.585-589
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    • 1991
  • We experienced a rare hepatic tuberculous granuloma with subphrenic abscess. The patient was 45-years old female. She complained the right flank pain and tenderness on the protruding mass for 2 weeks. It was fixed, erythematous and 5x5cm sized mass, which was thought as cold abscess. She has done the hysterectomy as endometriosis at November 1990. Under general endotracheal anesthesia, the mass was incised, but the pus was not found. The needle aspiration was done through the 8th ICS, then the yellowish non-foul odor pus was rushed out. The 7th and 8th ribs were resected segmentally about 5cm. The abscess cavity was placed in the subphrenic area, therefore the operative fields extended along the 8th ICS. After the evacuation of subphrenic abscess, the granulomatous tissues from the superior aspect of liver was seen. The granuloma was resected and the penrose drainage was inserted. The tuberculosis was resulted from the 8th ICS muscles. subphrenic abscess and granuloma on the pathology report.

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변색된 치아의 심미성 회복에 관한 임상증례 (ESTHETIC IMPROVEMENT OF DISCOLORED TEETH : A CASE REPORT)

  • 정호석;김대업
    • 대한소아치과학회지
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    • 제21권2호
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    • pp.593-598
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    • 1994
  • There were two cases of esthetic improvement of discolored teeth. First case was 12-year-old girl whose upper right central incisor was discolored after traumatic injury. She was treated by walking bleaching technique. Endodontic retreatment was done, and then the mixture of Superoxol and sodium perborate was applied and changed every week. After 3 weeks, esthetic result was obtained and fracture site was rcovered with light-curing composite resin. Second cases was 11-year-old girl whose teeth were discolored by fluorosis. She was treated by vital bleaching technique. A resin splint was made and then 30% and 15% carbamide peroxide was applied using this splint. After 4 weeks, a noticeable improvement in the color and the brightness of the teeth was achieved.

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표면온도 및 조도분포가 있는 경우 난류경계층의 완충층 거동에 관한 연구 (A Study on the Behavior of Buffer Layer in Turbulent Boundary Layer with Variation of Surface Temperature and Roughness)

  • 정동빈
    • 수산해양기술연구
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    • 제35권1호
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    • pp.83-92
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    • 1999
  • In this paper, the wind tunnel test was carried to investigate the behavior of buffer layer in turbulent boundary layer with variation of surface temperature and roughness. The results were as follows; 1. The velocity in turbulent boundary layer was increased when the roughness height within viscous sublayer thickness was increased. 2. When the surface temperature was increased, the density of air was decreased and the velocity in turbulent boundary layer was increased. Thus, the thickness of turbulent boundary layer was decreased. 3. When the roughness height and surface temperature was increased simultaneously, the thickness of turbulent boundary layer was decreased. 4. The decrement of the thickness of turbulent boundary layer was more effected by the increment of the roughness height rather than the increment of surface temperature. 5. In this study, it was found that the condition of the highest velocity n turbulent boundary layer was the temperature 333K and roughness #100.

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개 전안방 안구사상충증 (Ocular Filariasis in Canine Anterior Chamber)

  • 김기홍;엄혜윤;나기정;양만표
    • 한국임상수의학회지
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    • 제16권2호
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    • pp.506-508
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    • 1999
  • An one-year-old, female pointer dog with conjunctival hyperemia, corneal opaque and ocular pain in right eye was referred to Veterinary Medical Teaching Hospital, Chungbuk National University. In the ophthalmic examination the worm was observed in anterior chamber, The heart worm antigen test was positive. A modified Knott's test was negative. The values of complete blood count and serum chemistry (TP, BUN, creatinine, AST, ALT, ALP, albumin, globuline) showed normal ranges. Any abnormality was not detected in the heart using a thoracic radiography and cardiac sonography. Therefore, this dog was diagnosed as ocular filariasis. The worm was removed by surgical incision through a limbus of cornea. The closure of limbal incision was sutured in a simple interrupted suture pattern with 6-0 silk and the eye was reinflated with sterile saline solution. Antibiotics and dexamethasone ophthalmic solution were applied to right eye every 24 hours for 7 days. To prevent latent filariasis, ivermectin was also administered on day 14 of operation. The heart worm antigen test on day 60 was negative. The dog was successfully cured.

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가연성 폐기물의 가스화에 관한 연구 (A Study on the Gasification of Combustible Waste)

  • 정준화
    • 한국환경보건학회지
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    • 제16권2호
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    • pp.89-95
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    • 1990
  • This study was investigated to the energy recovery by the pyrolysis of waste tyre. the pyrolysis of the waste tyre was made by using the pyrolysis chamber for the gasification and the combustion chamber for the combustion of the pyrolysis gas. In batch system, the amount of waste tyre was put 150kg in the pyrolysis chamber and the proper air flow rate for the stable production of the pyrolysis gas was 0.95Nm$^{3}$ /min. the production time of the pyrolysis gas was stable above 210minutes, and the stable production rate was above 3.8Nm$^{3}$ /min. The production temperature of pyrolysis gas was 170$^{\circ}$C and combustion temperature of pyrolysis gas was 1,000$^{\circ}$C. The combustible component of washing gas in pyrolysis gas of waste tyre was CO, CH$_{4}$, $C_{2}H_{6}$ and $C_{3}H_{8}$, and total amount was 22.7%. Heat value of condensed material was 9,804Kcal/kg. The average concentration of air pollutants between cyclone and scrubber was CO 420.4ppm, SO$_{x}$ 349.8ppm. NO$_{x}$ 68.Sppm, HCl 24.4ppm and Dust 240.0g / Nm$^{3}$, respectively.

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일반탄소강의 상변태 중 발열 특성 해석 (Characteristics of Heat Generation during Transormation in Carbon Steels)

  • 한흥남
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.196-201
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    • 2000
  • A thermodynamic model was developed to analyze the characteristics of the heat generation during transformation of austenite in 0.186wt% and 0.458 wt%. carbon steels. The heat capacity and the heat evolved during transformation were formulated as functions of temperature and chemical composition for ferrite bainite and pearlite. in addition using the transformation dilatometer the transformation heat evolved during cooling was measured and the transformation behavior was observed. It was found that the heat capacity of ferrite was similar to those of pearlite and bainite. The heat capacity of ferrite was greater than that of bainite which was greater than that of pearlite. The molar heat of transformation to pearlite was greater than that to bainite which was greater than that to ferrite. The heats were found to be increased with decreased temperature and increasing the carbon content, It was also observed that the thermodynamic model. The heat of transformation in the higher carbon steel was greater than that in the lower carbon one. This was attributed to the lower transformation temperature and the greater amount of transformed pearlite in the higher carbon steel.

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낙안읍성의 공간구성 변화에 관한 조사연구 (A Study on the Change of Space Organization of Nagan Eupsung)

  • 길종원;신웅주
    • 한국농촌건축학회논문집
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    • 제12권2호
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    • pp.1-12
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    • 2010
  • The results of Change of Space Organization of Nagan Eupsung are as follows. There was no castle when Nagan folk village was built and it was merely small village arranged centering around road, but as it was emphasized as a point of strategic importance, castle wall was built and the government office and military facilities were established. In the late period of the Joseon Dynasty, as central power was weakened and its importance as a strategic point was declined, private houses outside the folk village were extended to the inside of castle. The whole structure of the village was not greatly changed through the modern society, but disappearance of village components and change of its basic structure like destruction of the castle were continued not to be restored to the former condition spontaneously. It was considered that it was caused by social demographic characteristics of the folk village which was deteriorated and environmental factors that it was changed into sightseeing place.

후천성 심질환의 인공판막치환술에 대한 임상적 고찰 (Clinical Analysis of Prosthetic Valve Replacement on Acquired Heart Disease)

  • 이준영;지행옥
    • Journal of Chest Surgery
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    • 제22권6호
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    • pp.951-959
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    • 1989
  • Between September, 1972 and September, 1989, total 359 patients were operated for acquired heart disease at Department of Thoracic and Cardiovascular Surgery, Hanyang University Hospital. A consecutive series of 293 prosthetic valve replacement was also performed during this period. The results were summarized as follows; 1. There were 141 men and 218 women, whose ages ranged from 6 to 64 years, [mean 35.5 years] 2. Out of 293 cases, mitral valve replacement was 182 cases, aortic valve replacement was 39 cases and double valve replacement was70 cases. 3. Early post-operative death was 30 cases [Mortality; 8.4 %] and late death was 9 cases in the survivors. 4. Re-operation was 30 cases and operative mortality was 10%. 5. Mean post-operative interval was 76 months. [Ranged from 216 months to 2 months] 6. Among re-operation cases, primary prosthetic valve failure was 16 cases and paravalvular leakage was 2 cases. 7. Since January 1988, 79 cases of prosthetic valve replacement were performed and then 1 case was expired. [Mortality; 1.2 %]

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수문자료 빈곤지역에서의 저수지 규모 결정 모의 모형 개발 (Development of a Simulation Model for Reservoir Sizing in a Region with Insufficient Hydrological Data)

  • 최진규
    • 한국농공학회지
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    • 제42권4호
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    • pp.67-75
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    • 2000
  • A simulation model for reservoir sizing was developed to be applied in a region with insufficient hydrological data. Reservoir storage balance equation was formulated on a monthly basis. Gajiyama equation was generalized to estimate monthly reservoir inflow more accurately. Monthly evaporation equation on a reservoir water surface was introduced , which was functioned with monthly mean temperature. Generalized Gajiyama equation was applied to estmate reservoir inflow of the Sayeon dam. Nash-Sutcliffe's model efficiency was 0.793. Using developed model for reservoir sizing, water supply capacity was analyzed with 118.000㎥/day on the Sayeon dam. This showed a reasonable result as compared with 110000㎥/day in other technical report. For general application of developed model, a virtual reservoir was considered and its dta of surface area and volume by elevation was prepared using DEM. Using the model, size of reservoir was determined and water supply capacity was anlayzed on a virtual reservoir.

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