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이수경,엄종호,하동명,이성민 한국산업안전학회 1992 한국안전학회지 Vol.7 No.3
A general theory is developed which enables closed-cup flash points of mixtures of flammable and non-flammable liquid to be estimated from a knowledge of a certain properties of flammability diagram by thermodynamic method. The estimated equations is shown the effect of both the flame inhibiting properties of the vapor of the non-flammable component and the relative volatility of that component. The vapor phase flame inhibition effect results in a even greater elevation of flash points than the relative volatility of that component. Especially in cases of similar vapor phase flame inhibition of the nonflammable component, the relative volatility is affected greater elevation of flash points(extinguishing effect).
409L페라이트계스테인리스강CO2레이저용접부의미세조직과경도
공종판 ( Jong Pan Kong ),박태준 ( Tae Jun Park ),나혜성 ( Hye Sung Na ),엄상호 ( Sang Ho Uhm ),김정길 ( Jeong Kim Kim ),우인수 ( In Su Woo ),이종섭 ( Jong Sub Lee ),강정윤 ( Chung Yun Kang ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 대한금속·재료학회지 Vol.48 No.4
The microstructure and hardness of CO2 laser welds were investigated in the Ti-stabilized ferritic stainless steel 409L. The observed specimen was welded in a fully penetrated condition in which the power was 5 kW and the welding speed 5 m/min. The grain structure near the bond line of the laser welds was produced by epitaxial growth. The grain size was the largest in the fusion zone, and HAZ showed nearly the same grain size as that of the base metal. The HAZ microstructure consisted of subgrains and precipitates that were less than l00 nm in size and that were located along the subgrain boundaries. On the other hand, the hardness was the highest in the fusion zone due to the large amount of small precipitates present. These were composed of TiN, Ti(C,N) and TiO2+Ti(C,N). The hardness decreased continuously from the fusion zone of the base metal. The HAZ hardness was slightly greater than that of the base metal due to the existence of subgrains and precipitates in the subgrain boundary. (Received January 13, 2010)
제조합 대장균에서 과발현된 Citrobacter freundii KCTC2006 유래의 β-Tyrosinase를 이용한 3,4-Dihydroxyphenyl-L-alanine의 생산
이승구,노현수,홍승표,이규종,왕지원,태동년,엄기남,방상구,김영준,성문희 한국미생물생명공학회 ( 구 한국산업미생물학회 ) 1996 한국미생물·생명공학회지 Vol.24 No.1
재조합 대장균에서 대량발현 시킨 Citrobacter freundii KCTC 2006 유래이 효소 β-tyrosinase를 이용하여 pyrocatechol, sodium pyruvate, ammonium acetate로부터 3,4-dihydroxy phenyl-L-alanine을 생산하기 위한 연구를 수행하였다. 이 효소반응에 적합한 온도 및 pH 조건은 각각 18℃와 8.5로 결정되었고, 반응액 중의 ammonium acetate와 sodium pyruvate의 농도는 각각 300 mM, 50 mM 이상으로 조절하는 것이 적합하였다. Pyrocatechol의 경우는 20 mM에서 가장 높은 반응성을 나타냈으나, 기질을 반복적으로 첨가하며 장시간 동안 효소반응을 수행하는 경우에는 pyrocatechol의 고갈을 피하기 위하여, 20 mM에서 50 mM 사이로 조절하였다. 한편, 반응액 중에 ethanol을 10% 첨가한 경우에는 반응속도가약 20% 증가하였다. 이상과 같은 효소반응특성에 기초하여 조제한 기질용액에 β-tyrosinase를 1 unit/㎖ 농도로 가하고, pyrocatechol과 pyruvate가 고갈되지 않도록 간헐적으로 첨가하면서 효소반응을 수행한 결과, 24시간 만에 85.2%의 수율로 31.6g/ℓ의 3,4-dihydroxyphenyl-L-alanine를 생산할 수 있었다. By using the β-tyrosinase of Citrobacter freundii KCTC2006, which was cloned and overexpressed in Escherichia coli, 3,4-dihydroxy phenyl-L-alanine (L-DOPA) was synthesized efficiently from pyrocatechol, sodium pyruvate, and ammonium acetate. Optimal temperature and pH for the reaction were determined to be about 18℃ and 8.5, respectively. The effects of substrate concentrations were also examined at different concentrations of ammonium acetate, sodium pyruvate, and pyrocatechol. Ammonium acetate and sodium pyruvate increased the reaction rate until the concentrations reached to 300 mM and 50 mM, respectively. Although pyrocatechol showed the optimal concentration at 20 mM, it was controlled between 20 mM and 50 mM to avoid the depletion of substrate during the enzymatic synthesis. Based on above results, a reaction medium for the production of L-DOPA was prepared and incubated with 1 unit/㎖ of β-tyrosinase. Pyrocatechol and sodium pyruvate was added to the reaction solution intermittently to avoid the substrate depletion during the enzymatic reaction. After 24 hour of reaction, 31.6 g/ℓ L-DOPA was accumulated in the reaction solution as soluble and precipitated ones and the conversion yield was about 85.2%.
( Young Hoon Lee ),( Jong Su Uhm ),( Soo Hyun Yoon ),( Ji Young Kang ),( Eun Kyung Kim ),( Beom Sik Kang ),( Do Sik Min ),( Young Seuk Bae ) 생화학분자생물학회 2011 BMB Reports Vol.44 No.9
Elevated phospholipase D (PLD) expression prevents cell cycle arrest and apoptosis. However, the roles of PLD isoforms in cell proliferation and apoptosis are incompletely understood. Here, we investigated the physiological significance of the interaction between PLD2 and protein kinase CKII (CKII) in HCT116 human colorectal carcinoma cells. PLD2 interacted with the CKIIβ subunit in HCT116 cells. The C-terminal domain (residues 578-933) of PLD2 and the N-terminal domain of CKIIβ were necessary for interaction between the two proteins. PLD2 relocalized CKIIβ to the plasma membrane area. Overexpression of PLD2 reduced CKIIβ protein level, whereas knockdown of PLD2 led to an increase in CKIIβ expression. PLD2-induced CKIIβ reduction was mediated by ubiquitin-dependent degradation. The C-terminal domain of PLD2 was sufficient for CKIIβ degradation as the catalytic activity of PLD2 was not required. Taken together, the results indicate that the C-terminal domain of PLD2 can regulate CKII by accelerating CKIIβ degradation in HCT116 cells. [BMB reports 2011; 44(9): 572-577]
Park, Tae Jun,Kong, Jong Pan,Uhm, Sang Ho,Woo, In Su,Lee, Jong Sub,Kang, Chung Yun Elsevier 2011 Journal of materials processing technology Vol.211 No.3
<P><B>Abstract</B></P><P>In this study, commercial 409L ferritic stainless steels and Al–8wt% Si alloy-coated 409L ferritic stainless steels were subjected to gas tungsten arc welding and the effect of the coated layer on the penetration properties and microstructure were investigated. Full penetration was obtained with a welding current greater than 90A and a welding speed lower than 0.52m/min. At the full penetration condition, the bead width of Al–8wt% Si alloy-coated 409L ferritic stainless steels was narrower than that of commercial 409L ferritic stainless steels. In these samples, a narrow and deep weld pool was considered to have formed under gas tungsten arc welding due to Marangoni convection with existing oxides in the Al–Si coating layer. The grain size of both materials was the largest in the fusion zone and decreased from near the heat-affected zone to the base metal. Especially, the grain size of the heat affected zone and the fusion zone of Al–8wt% Si alloy-coated 409L ferritic stainless steels were small compared to those of commercial 409L ferritic stainless steels. The hardness was maximized in the fusion zone and decreased from the bond line to the base metal. The maximum hardness in the fusion zone was attributed to the re-precipitation of the TiN and Ti(C, N), which were present in the base metal with the finer grain size during the melting and solidification processes. However, the maximum hardness of Al–8wt% Si alloy-coated 409L ferritic stainless steels was relatively high due to the formation of oxides such as Al<SUB>2</SUB>O<SUB>3</SUB> and SiO<SUB>2</SUB> that originated from the dissolved elements from the coating layer.</P>
Al-Si 용융도금된 11%Cr 페라이트 스테인리스강, STS409L GTA 용접부의 미세조직과 경도
박태준,공종판,나혜성,강정윤,엄상호,김정길,우인수,이종섭,Park, Tae-Jun,Kong, Jong-Pan,Na, Hye-Sung,Kang, Chung-Yun,Uhm, Sang-Ho,Kim, Jeong-Kil,Woo, In-Su,Lee, Jong-Sub 대한용접접합학회 2010 대한용접·접합학회지 Vol.28 No.3
Ferritic stainless steels, which have relatively small thermal expansion coefficient and excellent corrosion resistance, are increasingly being used in vehicle manufacturing, in order to increase the lifetime of exhaust manifold parts. But, there are limits on use because of the problem related to cosmetic resistance, corrosions of condensation and high temperature salt etc. So, Aluminum-coated stainless steel instead of ferritic stainless steel are utilized in these parts due to the improved properties. In this investigation, Al-8wt% Si alloy coated 409L ferritic stainless steel was used as the base metal during Gas Tungsten Arc(GTA) welding. The effects of coated layer on the microstructure and hardness were investigated. Full penetration was obtained, when the welding current was higher than 90A and the welding speed was lower than 0.52m/min. Grain size was the largest in fusion zone and decreased from near HAZ to base metal. As welding speed increased, grain size of fusion zone decreased, and there was no big change in HAZ. Hardness had a peak value in the fusion zone and decreased from the bond line to the base metal. The highest hardness in the fusion zone resulted from the fine re-precipitation of the coarse TiN and Ti(C, N) existed in the base metal during melting and solidification process and the presence of fine $Al_2O_3$ and $SiO_2$ formed by the migration of the elements, Al and Si, from the melted coating layer into the fusion zone.
중력보상 관절구동기를 적용한 로봇 매니퓰레이터의 실험적 연구
최형식(Hyeung-Sik Choi),서해용(Hae-Yong Seo),엄태웅(Tai-Woong Uhm),윤종수(Jong-Su Yoon) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
In this paper, the structure of a gravity compensator was studied, and the 6-axis robot manipulator which is newly developed by applying the gravity compensator is presented to improve the torque performance of the robot joint. The kinematics analysis on the robot was presented. Also, a experiment of the performance of the joint actuator of robot adopting the gravity compensator was presented by applying various springs. According to the experiment results, it was validated that the payload effect on the robot joint actuator adopting the gravity compensator is reduced in proportion to the spring intensity of the gravity compensator.
Seo Mi Ryoung,Kim Gunwoo,Moon Ki Won,Sung Yoon-Kyoung,Yoo Jong Jin,Yoon Chong-Hyeon,Lee Eun Bong,Lee Jisoo,Kang Eun Ha,Kim Hyungjin,Park Eun-Jung,Uhm Wan-Sik,Lee Myeung Su,Lee Seung-Won,Choi Byoong Yo 대한의학회 2021 Journal of Korean medical science Vol.36 No.17
Background: There is increasing interest in the quality of health care and considerable efforts are being made to improve it. Rheumatoid arthritis (RA) is a disease that can result in favorable outcomes when appropriate diagnosis and treatment are provided. However, several studies have shown that RA is often managed inappropriately. Therefore, the Korean College of Rheumatology aimed to develop quality indicators (QIs) to evaluate and improve the health care of patients with RA. Methods: Preliminary QIs were derived based on the existing guidelines and QIs for RA. The final QIs were determined through two separate consensus meetings of experts. The consensus was achieved through a panel of experts who voted using the modified Delphi method. Results: Fourteen final QIs were selected among 70 preliminary QIs. These included early referral to and regular follow-up with a rheumatologist, radiographs of the hands and feet, early initiation and maintenance of disease-modifying anti-rheumatic drug (DMARD) therapy, periodic assessment of disease activity, screening for drug safety and comorbidities, including viral hepatitis and tuberculosis before biologic DMARD therapy, periodic laboratory testing, supplementation with folic acid, assessment of the risk for cervical spine instability before general anesthesia, patient education, and specialized nurse. Conclusion: These QIs can be used to assess and improve the quality of health care for patients with RA.