Formation Mechanism of silicon Carbide layer during self-propagating high temperature synthesis

최용 선문대학교 1999 공과대학논문집 Vol.1 No.2

흑연과 규소층을 고온연소합성시켜서 탄화규소 층을 합성하였다. Auger 전자현미경과 X-선 회절시험으로써 고온연소합성된 생성물은 β-SiC 층이며 계면에 상호확산 층은 관찰되지 않았다. 이론적 연소한계는 초기 반응온도에 따라 감소하였다. 상온과 1200℃에서의 연소한계는 각각 0.37과 0.06이었다. 이는 연소반응을 위하여 예열이 필요함을 의미한다. 탄화규소의 합성을 위한 활성화에너지는 액상 규소와 탄소화이버 또는 흑연을 사용하였을 경우에 각각 2875 and 1782 KJ/mole이었다. 연소개시온도, 활성화에너지 및 미세조직 관찰을 통하여 연소반응중에 합성되는 탄화규소는 탄소원자 가 액상규소와 탄화규소를 확산함으로써 성장하는 것으로 사료된다. Silicon carbide was deposited by self-propagating high temperature synthesis reaction between graphite and silicon layers. Chemical analyses by auger electron microscopy and X-ray diffractometry revealed that the final product was relatively dense microstructure of beta-SiC and an interdiffusional layer was not observed at the interface. Numerical analysis of the combustion behavior showed that the combustion limit decreases with initial reaction temperature. The estimated values of the combustion limit at room temperature and 1200℃ were 0.37 and 0.06, respectively. This supports that additional heat is required for the complete reaction. Activation energies for the formation of the silicon carbide between liquid silicon and carbon fiber or carbon black were 2875 and 1782 KJ/mole, respectively. Considering ignition temperature, activation energies and microstructural observations, silicon carbide prepared by the combustion reaction between silicon and carbon was formed by the carbon diffusion at the interface of liquid silicon and silicon carbide.

폐형광등 형광분말(Phosphor powder)의 활용방안에 대한 연구

최용,양희성,고영근,박주은,최형진,박헌수,이승희 한국폐기물자원순환학회 2014 젊은 연구자 학술연구발표회 Vol.13 No.0

콤팩트형 형광등(CFLs) 재활용 시 공기선별에 의한 종이 및 비닐의 선별효율 평가

최용,최형진,김성호,이승희 한국폐기물자원순환학회 2016 젊은 연구자 학술연구발표회 Vol.14 No.0

만성 신부전증 환아에서 성장호르몬 투여후 성장속도의 변화

최용,문형로,양세원 대한내분비학회 1993 Endocrinology and metabolism Vol.8 No.2

We studied the effect of rhGH on the growth in seven children with chronic renal failure(CRF). All seven children showed normal GH responsed (peak GH response, more than 10 ng/mL) to classical GH provocative tests (L-dopa, Arginie), which results did not differ from that of healthy children. The change of height SDS for 1 year of rhGH treatment was from -3.47±1.31 to -2.74±1.57, which had no statistical significance (p$lt;0.1) The growth velocity during 1 year prior to and following rhGH treatment increased from 2.78±0.85 cm/hear to 11.24±7.90 cm/year, respectively, which had statistical significance (p$lt;0.05). One child who had had successful renasl transplantation showed an increase in the height SDS from -5.4 to -4.0 and an increase in the growth melocity from 3.2cm/year to 12.2 cm/year with rhGH treatment. The predicted adult height, obtained by Tanner-Whitehouse method, following GH treatment increased from 151.9±5.7 cm to 160.4±10.3 cm, which had marginally statistical significance(p=0.05) Subcutanat mass measured with triceps subcutaneous skin fold, decreased significantly with significant increase in muscle mass follwing rhGH treatment (p$lt;0.05) Through the period of rhGH treatment, we could not observe any side effect of GH treatment, such as hypothyroidism, glucose intolerance, or aggravation of renal function. Also we could not observe any exaggerated advancement of bone maturation(0.6±0.2 year/chronological year) during rhGH treatment, but less than the advancement of chronological age. (J Kor Soc Endocrinol 8: 157~163, 1993)

초등 도덕과와 연계된 창의적 체험 활동 : "다문화능력 개발을 위한 창의/인성교육 프로그램의 활용"에 대한 토론

최용 한국초등도덕교육학회 2010 초등도덕교육 Vol.0 No.33

백서의 사구체 격측상피세포의 배양가 성상확인

최용,하태선 대한신장학회 1995 Kidney Research and Clinical Practice Vol.14 No.4

For the purpose of evaluating the origin of cultured glomerular epithelial cells(GEC), we applied immunohistochemical(IHC) and electron microscopic (EM) studies to characterize the cultured rat GEC. After isolation by differential sieving method, glomeruli were explanted and maintained in a medium(K1-3T3) consisting of equal parts of a Kl medium and conditioned medium taken from cultures of NIH 3T3 fibroblasts grown in Dulbecco's modified Eagle's mediurn plus 10% fetal calf serum. Morphologically distinct GEC grew out from the isolated glomeruli and they were cultured continuously. The grown GEC(early stage within 7 days after glomerular explantation) and continuously cultured cells were characterized by IHC using primary antibodies, such as, monoclonal antibodies to cytokeratin, desmin, Thy 1.1, and vimentin and EM methods. At the sarne time, their results were compared with those of glomerular epithelium from rat kidney sections. The inverted light microscopic features of continuously cultured GEC were similar to those of primarily cultured GEC. Both prirnarily and continuously cultured GEC stained positive for cytokeratin and negative for desmin, Thy 1.1, and vimentin, which results were identical to the IHC results of parietal cells in situ. On the contrary, visceral epithelial cells in situ stained positive for vimentin and desmin and negative for cytokeratin. These results suggested that rat GEC in primary and continuous culture, expressed IHC characteristics of in situ parietal, not visceral epithelium. We could observe junctional complexes of the desmosome type in cultured GEC which were noted in parietal epithelial cells, not in visceral cells. In conclusion, the cultured epithelial cells might be glomerular parietal epithelial cells by comparing the IHC and EM characteristics of cultured GEC with glomerular epithelium from rat kidney sections. Therefore, we can use these cultured and characterized glomerular parietal epithelial cells (GPEC) for the study of their biologic functions or of the pathophysiology of GPEC-associated diseases, such as, crescentic glomerulonephritis.

Manufacturing and Performance Teste of In-pile Creep Measuring Machine of Zirconium Alloy

최용,김봉구,강영환 한국원자력학회 2000 春季學術發表會論文集 Vol.2000 No.-

하나로 내에서 지르코늄 합금의 조사 크립시험을 수행하기 위한 조사 크립 시험용 크립시험장치의 목합(mock-up)을 설계·제작하고 부품별 성능시험을 수행하였다. 목합은 하나로에 적합하도록 직경과 길이가 각각 55×700mm이었다. 하중은 가스압에 의하여 벨로우즈(bellows)를 균일하게 수축시켰고 回자형 이음쇠(yoke)와 그립(grip)을 통하여 시편에 전달되었다. 그립에 설치된 시편의 변형량은 이은쇠와 밀대(push rod) 및 환형 베어링을 통하여 선형변위차등변압기에 정확하게 전달되었다. 하중에 따른 시편의 변위는 선형변위차등변압기(Linear Voltage Differential Transformer, LVDT)와 압력계를 사용하여 측정하였다. 이를 통하여 직경 3mm의 인장 시편의 하중-변위 곡선을 얻었다. A mock-up of the in-pile creep test machine of zirconium alloys for HANARO was designed and manufactured, which performance tests were carried. The dimension of the in-pile creep machine is 55 mm in diameter and 700 mm in length for HANARO, respectively. Load is transferred to specimen by through the working mechanisms in which the contraction of bellows by gas pressure moves a yoke and an upper grip connected to a specimen, simultaneously. It was observed that the extension of the specimen mounted in grips was transferred to a linear voltage differential transformer perfectly by a yoke and a push rod in a bearing. The displacement of specimen with applied pressure was determined with the LVDT and a pressure gauge, respectively. Resultant stress-strain behaviors of the specimen was determined by the displacement-applied gas pressure curve, which showed similar values obtained with a standard tensile test machine.

Effect of Chloride Ion on the Corrosion Behavior of Functionally Graded Zirconium Alloy

최용 선문대학교 1998 공과대학논문집 Vol.1 No.1

나요비윰(Nb)의 조성이 점진적으로 변화하는 경사성기능의 지르코늄 합금을 HIP와 냉간가공으로 제조하고 내식성을 전기화학적인 방법으로 조사하였다. X-선 회절 시험으로 고온 음극 충진으로 생성된 수소화합물은 γ-ZrH과 δ-ZrH_(1.6) phases이었으며 입계를 걸쳐서 비교적 균일하게 분포되어 있었다. 내식성은 붉은 염산 수용액에서 수소화합물의 생성에 따라 감소하였다. 수소화합물이 생성된 경사성 기능의 지르코늄 합금에서 공침과 부식산물이 관찰되었다. The zirconium alloy with composition gradient of niobium was prepared with a hot isostatic pressing followed by cold deformation to develop an advanced nuclear cladding tubing and corrosion behavior of functionally graded zirconium alloy was studied. X-ray diffractometry revealed that the hydrides prepared by a high temperature cathodic charging method were γ-ZrH and 5-ZrH_(1.6) phases, which homogeneously distributed across the grains. Corrosion resistance in dilute hydrochloric acid solution decreased with the hydride content. SEM observation showed that brittle fracture with corrosion products and pits occurred were observed on the failed surface of hydrided zirconium alloy

童話的 體驗과 想像力의 夙成

崔湧 한국아동문학학회 2001 한국아동문학연구 Vol.- No.9

소아에서의 혈액투석

최용 대한신장학회 1988 Kidney Research and Clinical Practice Vol.7 No.3