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Gaseous by-products from the TiO₂ Photocatalytic Oxidation of Benzene
Sang Wook Han,Jin Hong Lee,Jin Seog Kim,Sang Hyub Oh,Young Kwon Park,Hyun Ook Kim 대한환경공학회 2008 Environmental Engineering Research Vol.13 No.1
Photocatalytic oxidations of benzene gas using the closed system (batch reactor) were induced to determine its by-products and investigate the effect of humidity and oxygen concentration on their generation. The study was able to identify 11 gaseous by-products: 2-methylpropene, acetaldehyde, acetone, pentane, methylcyclobutane, methylcyclopentane, cyclohexane, 2,3-dimethylbutane, 2-methylpentane, 3-methylpentane, and hexane. All the by-products were saturated hydrocarbons, which are less toxic than benzene and were probably formed through hydrogenation reaction on the photocatalytic surface. The photocatalytic oxidation of benzene under higher humidity produced less by-products. However, the amount of acetone released increased with higher humidity and oxygen concentration.
Oh, Sang-Hyub,Kim, Myung-Soo,Lee, Jin-Bok,Lee, Heung-Lark,, Myung-Soo Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.1
Cycle life tests have been carried out to evaluate the influence of safety valve pressure on valve regulated lead/acid batteries under deep cycling applications. Batteries were cycled at 5 hour rates at 100% DOD, and safety valve pressure was set to 1.08 and 2.00 bar, respectively. The batteries lost 248.3 g and 235.3 g of water for each case after about 1,200 cycles, but the cyclic performances of the batteries were comparable. Most of the gas of the battery during discharging was hydrogen, and the oxygen concentration increased to 18% after 3 hours of charging. The micro structure of the positive active materials was completely changed and the corrosion layer of the positive grid was less than $50{\mu}m$, regardless of the pressure of the safety valve after cycle life tests. The cause of discharge capacity decrease was found to be water loss and the shedding of the positive active materials. The pressure of safety valve does not give little effect to the cyclic performances and the failure modes of the gelled electrolyte valve-regulated lead acid batteries.
Evaluation of changes in cylinder volume due to gas filling and subsequent release
Oh, Sang Hyub,Kim, Byung Moon,Kang, Namgoo Springer-Verlag 2013 Metrologia Vol.50 No.4
<P>This paper provides useful and important information in gas metrology especially where high-precision gas mixtures are essential. Buoyancy effects due to cylinder expansion are taken into account as a source of uncertainty in weighing for the preparation of primary or standard gas mixtures by gravimetric methods. Potential effects of cylinder construction materials, nominal volumetric capacity and filling gas species on cylinder volume during the preparation of primary standard gas mixtures remain unknown in the current literature. It is also difficult to find experimental evidence to demonstrate the theory that cylinder expansion upon pressurization is linear. We therefore devised an indirect measurement method to measure apparent volume changes and ultimately estimate changes in the volume of highly pressurized cylinders. We found that changes in the volumes of some gas cylinders varied significantly with construction material and nominal volumetric capacity. The relative volume changes for aluminium alloy cylinders were about 30% higher than those for manganese steel cylinders regardless of the nominal volumetric capacity and the filling gas species. We also provide experimental evidence verifying that changes in cylinder volume follow nearly linear patterns within the pressure range from 12 MPa to 0.1 MPa. Our estimate for the volume expansion of an aluminium alloy cylinder of 5 dm<SUP>3</SUP> capacity with a pressure difference of 15 MPa is (15 ± 2) cm<SUP>3</SUP>. The reported value of about 20 cm<SUP>3</SUP> in ISO 6142 : 2001 would be regarded as a rough estimate.</P>
조상연(Sang Yeon Cho),오승협(Seung Hyub Oh) 한국추진공학회 2012 한국추진공학회 학술대회논문집 Vol.2012 No.5
한국항공우주연구원에서는 현재 1.5톤급 위성 발사체인 한국형 발사체 KSLV-Ⅱ를 개발중이며 시스템의 설계 리뷰를 앞두고 있다. 또한, 발사체의 개발과정에 있어서 임무 보증 업무의 일환으로 신뢰성과 안전, 품질등을 관리하고 있으며 발사체의 안전 확보를 위해서 기존에 공표된 안전 보장 계획 및 시스템 안전 프로그램 계획에 따라 관련 업무를 수행하고 있다. 본 연구에서는 상기의 계획에 의거하여 수행된 사전 안전 분석의 내용과 방법에 대하여 설명하고 실제 추진기관 시스템에 대하여 도출된 위험요소들을 소개하고자 한다. 도출된 위험 요소들은 향후 개발이 진행되면서 위험 수준을 완화하는 방향으로 관리될 계획이다. KARI is now developing KSLV-Ⅱ which can insert 1.5ton satellite into the orbit, and system design review is close at hand. As a part of mission assurance for space launch vehicle, reliability and safety management is being performed and to assure the safety, KARI has been doing actions on the basis of the safety assurance plan and system safety program plan. In this study, preliminary hazard analysis is reviewed and the result for the propulsion system will be illustrated. The result will be used as a reference for the safety and risk management.
( Hong Sang Oh ),( Joo Myung Lee ),( Sang Hyub Lee ) 대한내과학회 2011 대한내과학회 추계학술대회 Vol.2011 No.1
증례보고의 목적 및 강조 사항: Choledochal cyst is a rare disease; nonetheless, it has a clinical importance because of high incidence of biliary tract cancer, even in asymptomatic patient. The importance of complete cyst excision is commonly understood to prevent the development of malignancies and other complications. In this case, common bile duct cancer arising from remnant choledochal cyst, 9 years after excision of a choledochal cyst and it manifested as mucinous cystic neoplasm of the pancreas. To our knowledge, this is the first reported case in the English-language literature. 초록본문: We report a rare case of common bile duct cancer arising from remnant choledochal cyst which was incompletely excised 9 years ago, manifesting mucinous cystic neoplasm of the pancreas, respectively. A 42-years-old woman was admitted to our hospital because of dyspepsia and abdominal discomfort for 1 week. She had undergone operation for cholecochal cyst with gall bladder cancer 9 years ago; radical cholecystectomy including lymph node dissection and liver wedge resection, choledochal cyst excision, Roux-en-Y hepaticojejunostomy, distal pancreatectomy and splenectomy for multinodular hard mass in tail of pancreas. Pathology revealed a polypoid mass in gall bladder with liver infiltration as poorly differentiated adenocarcinoma, and a pancreatic tail mass as chronic pancreatitis. Based on her past medical history, we conducted imaging studies including CT, MRCP, EUS. Imaging showed a newly developed suspected solid nodule in the peripheral portion of cystic lesion in the pancreas head. She underwent a pylorus preserving pancreaticoduodenectomy for the suspected mucinous cystic neoplasm of the pancreas. At surgery, two hard mass were notified in the dilated remnant intrapancreatic choledochal cyst. Pathology revealed common bile duct cancer as poorly differentiated adenocarcinoma. The remnant choledochal cyst had developed to malignancy. Thus, complete excision is a crucial treatment strategy of choledochal cyst.
흐름주입법에 의한 Melamine 정량을 위한 Ruthenium-Ce(IV) 시스템의 백금 나노입자 증강 화학발광
이상학 ( Sang Hak Lee ),오상협 ( Sang Hyub Oh ),김영호 ( Young Ho Kim ),( M. Mahabub Khan ),( M. Arifur Rahman ),( Al Mahmnur Alam ),( Mohammad Kamruzzaman ) 한국공업화학회 2012 응용화학 Vol.16 No.1
A chemiluminescence (CL) method is reported for the determination of melamine by flow injection analysis (FIA). This method is based on the reaction of melamine with Ru(bipy)3 2+ and Ce(IV) in presence of colloidal platinum nanopartilces to produce CL. Under optimal condition, CL intensity was linearly related with melamine concentration. The calibration curve was linear over the range of 5.0×10-9-2.0×10-6 M with the limit of detection, 9.8×10-9 M. The relative standard deviation of 1.0×10-7 M melamine was found 2.5% (n=10).