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물 및 디메틸포름아마이드中에서 4-(2-Pyridylazo)-resorcinol의 分光電氣化學的 環元
李興洛,裵俊雄,李在鶴,吳相協 慶北大學校 1988 論文集 Vol.45 No.-
Spectroelectrochemistry involve the combination of an electrochemical technique with a spectroscopic techinque so that the two measurements may be performed simultaneously in an electrochemical cell. One of the most generally useful spectroelectrochemical technique involves spectral observation of a thin layer of solution. Thin-layer spectroelectrochemistry at the optically transparent thin-layer electrode(OTTLE) takes advantage of the rapid electrolysis (30∼60 sec.) and small volume features of thin-layer electrochemistry. This study has used controlled potential as the excitation signal. Potential control provides a facile means of presicely adjusting the redox potential of the thin solution layer as determined by the Nernst equation for reversible systems: E_applied=E^0'+0.059/n log (O)/(R) In experiment, the slopes of Nernstian plot were 28.3mV in aqeous solution and 53mV in N, N-dimethylformamide(DMF) solution. The results of this study showed that the reduction mechanisms of 4-(2-pyridylazo)-resorcinol(PAR) were one two-electron step in aqueous solution and two one-electrons steps in DMF solution. The formal reduction potentials(E^0') of the PAR were -0.574 volts vs. S.C.E. in aqueous soltion and -0.74 volts vs. Ag/AgClO_4 in DMF solution. These results were generally similar to the reduction mechanism of the other cyclic hydrocarbons in the aprotic solvent. In aprotic solvent, the product of the first electron transfer is expected to be a relatively stable anion radical. In this experiment tetraethylammonium perchlorate was used as a supporting electrolyte of the DMF solution.
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>
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.
( 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.
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.