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박동규,이경석,염훙열,황유동 순천향대학교 부설 산업기술연구소 2000 순천향 산업기술연구소논문집 Vol.6 No.1
In this paper, we propose a secure electronic transaction and management protocol to provide user authentication, data integrity, confidentiality and access control for secure medical management system based on internet. We prove the validation of the proposed protocol by implementing it and testing it's fuctions.
Bacillus lkicheniformis IAM 11054가 生産하는 耐熱性 α- Amylase의 特性과 分解産物에 關한 硏究
鄭萬在,南相烈,申敬娥 충북대학교 농업과학기술연구소 1987 農業科學硏究 Vol.5 No.2
These experiments were performed to investigate the purification, the characteristics and the hydrolysis products on various Polysaccharides and oligosaccharides of thermophilic α-amylase produced by Bacillus licheniformis IAM 11054. The optimum culture time, the optimum initial pH and the optimum culture temperature for the production of α-amylase were 72hrs, pH 6.5 and 40℃, respectively. The crude enzyme was purified to 568- fold by starch adsorption, ammonium sulfate fractionation, DEAE-cellulose column chromatography and CM cellulose column chromatography. The specific activity of the purified enzyme was 312.5u /mg ㆍ protein and the yield of enzyme activity was 13.0%. The purified enzyme showed a single band (relative mobility 0.25) on polyacrylamide gel electrophoresis and the molecular weight was estimated to be approximately 145,000 by SDS-polyacrylamide gel electrophoresis, and isoelectric point was pH6.0. The optimum pH, the stable pH range, the optimum temperature and the stable temperature of the purified enzyme were pH6.0∼7.5, pH6.0∼10.5. 80℃ and below 75℃, respectively. The purified enzyme was greatly inhibited by Hg++ Ag+ and I2, and the thermostability of it was greatly increased by Ca++. The purified enzyme hydrolyzed soluble starch, corn starch, glutinous rice starch, green banana starch, arrow root starch, potato starch, yam starch, oyster glycogen, maltopentaose and maltohexaose, but did not hydrloyze α, β, γ -cyclodextrin, pullulan, maltose, maltotriose, maltotetraose, raffinose, lactose and sucrose. The purified enzyme hydrolyzed various starch to G1, G2, G3, G4, G5, G6 and others, and G5 to G2 and G3 and G6 to G1, G2, G3, G4 and G5. Among various gelatinized starches, potato starch and green banana starch were favorably hydrolyzed by the purified enzyme.
Kyeong Youl Jung,Young-Kwon Park,Yu Ri Jung,전종기,Jung Hwan Kim,김승도 한국공업화학회 2011 Journal of Industrial and Engineering Chemistry Vol.17 No.1
Mesoporous V2O5/TiO2 particles with a spherical shape were prepared via spray pyrolysis, using P123 as a structure directing agent, and applied to the catalytic oxidation of 1, 2-dichlorobenzene (DCB). The texture properties of the prepared V2O5/TiO2 particles were monitored by changing the P123/Ti molar ratio from 0.03 to 0.07 and the vanadia content from 3 to 7 wt%. All the prepared samples had mesopores,but without any pore ordering. The sample prepared with a P123/Ti = 0.05 (molar ratio) had the largest surface area (142 m2/g) and smallest pore size (6.6 nm). The quantity of vanadia loading affected the texture properties as well as the crystallographic form of the V2O5/TiO2 particles. The major crystal phases of mesoporous V2O5/TiO2 particles were anatase, but 7–30% were formed in the rutile phase,which depended on the quantity of vanadia loading. However, the catalytic activity of V2O5/TiO2particles progressively increased with increasing quantity of vanadia loading. With 7 wt% V2O5/TiO2particles, 94% decomposition of 1, 2-DCB was achieved at 400 8C. The mesoporous V2O5/TiO2 particles prepared via spray pyrolysis showed higher catalytic activity compared with that prepared via the conventional impregnation method, which was due to the high dispersion of vanadia on the surface of pores. From the results obtained, the mesoporous V2O5/TiO2 particles prepared via spray pyrolysis were confirmed to have excellent activity for the oxidation of 1, 2-DCB, particularly at temperatures lower than 350 8C.
Kyeong Youl Jung,Yun Chan Kang,Young-Kwon Park 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.2
N,N-Dimethylformamide (DMF) was used as a drying control chemical additive (DCCA) in spray pyrolysis in order to improve the luminous properties of Y₂O₃:Eu particles. It was found that the addition of DMF to the spray solution containing citric acid (CA) and ethylene glycol (EG) greatly enhances the photoluminescence intensity as well as the morphology of Y₂O₃:Eu particles. According to BETanalysis, the surface area of Y₂O₃:Eu particles prepared from the solution containing only the organic additives was not reduced, whereas, the surface area of the Y₂O₃:Eu particles prepared from the solution containing both DMF and organic additives was decreased gradually as increasing the concentration of DMF. From these results, it was concluded that the adding of DMF to the spray solution containing the organic additives is a very effective way to reduce the porosity of phosphor particles, keeping the spherical morphology. As a result, the densification of porous structure led to greatly improve the photoluminescence intensity of Y₂O₃:Eu particles under ultraviolet (254 nm) excitation. Finally, the prepared Y₂O₃:Eu particles with dense structure showed about 208% improved photoluminescence intensity compared with the particles which have a spherical shape but porous structure.
분무열분해법으로 CeO2:Er/Yb 형광체 제조 및 발광특성 최적화
정경열 ( Kyeong Youl Jung ),박재훈 ( Jea Hoon Park ),송신애 ( Shin Ae Song ) 한국공업화학회 2015 공업화학 Vol.26 No.3
Submicron-sized CeO2:Er3+/Yb3+ upconversion phosphor particles were synthesized by spray pyrolysis, and their luminescent properties were characterized by changing the concentration of Er3+ and Yb3+. CeO2:Er3+/Yb3+ showed an intense green and red emission due to the 4S3/2 or 2H11/2 → 4I15/2 and 4F9/2 → 4I15/2 transition of Er3+ ions, respectively. In terms of the emission intensity, the optimal concentrations of Er and Yb were 1.0 % and 2.0%, respectively, and the concentration quenching was found to occur via the dipole-dipole interaction. Upconversion mechanism was discussed by using the dependency of emission intensities on pumping powers and considering the dominant depletion processes of intermediate energy levels for the red and green emission with changing the Er3+ concentration. An energy transfer from Yb3+ to Er3+ in CeO2 host was mainly involved in ground-state absorption (GSA), and non-radiative relaxation from 4I11/2 to 4I13/2 of Er3+ was accelerated by the Yb3+ co-doping. As a result, the Yb3+ co-doping led to greatly enhance the upconversion intensity with increasing ratios of the red to green emission. Finally, it is revealed that the upconversion emission is achieved by two photon processes in which the linear decay dominates the depletion of intermediate energy levels for green and red emissions for CeO2:Er3+/Yb3+ phosphor.
Jung, Kyeong Youl,Jung, Yu Ri,Jeon, Jong-Ki,Kim, Jung Hwan,Park, Young-Kwon American Scientific Publishers 2011 Journal of nanoscience and nanotechnology Vol.11 No.2
<P>Mesoporous V2O5/TiO2 particles were prepared by spray pyrolysis and applied to the catalytic oxidation of 1,2-dichlorobenzene (1,2-DCB). Two different precursors (alkoxide and nanoparticles) for the TiO2 support were used to determine the effects on the texture properties and the catalytic activity of the mesoporous V2O5/TiO2 particles. The 5 wt% V2O5/TiO2 particles had the largest surface area (173 m2/g) and 4.7 nm in average pore size. The catalytic activity of the V2O5/TiO2 particles depended strongly on the loading quantity of vanadium, whereas the P25-derived samples showed no significant change in catalytic activity with weight% of vanadium. The surface area of the V2O5/TiO2 particles prepared using the alkoxide precursor was larger than that of the particles prepared using P25 nanoparticles. The P25-derived V2O5/TiO2 particles, however, showed a higher catalytic activity compared with those alkoxide-derived, which is due to the difference in the vanadium quantity exposed to the pore surface. It was confirmed that the 10 wt% V2O5/TiO2 particles prepared by spray pyrolysis had an excellent activity for the oxidation of 1,2-DCB, particularly at temperatures below 300 degrees C.</P>