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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.
Structural Study of Antisense Dimers, Modified Adenosine-Thymidine Phosphorothioate
JUNG, KYEONG-EUN,YANG, MIRIM,LEE, KWANGJUN,LIM, HONG,JUNG, JIHYUN,KOO, BONJUNG,JEONG, LAK SHIN,SHIN, DONG-HOON,LEE, CHUL-HOON,CHO, YOUL-HEE,LIM, YOONGHO 梨花女子大學校 藥學硏究所 2000 藥學硏究論文集 Vol.- No.9
Antisense molecules are structurally simple linear oligomers of nucleotides. They can recognize a complementary sequence by base pairing, therefore, antisense drugs composed of 15-16 bases are potentially useful, unlike drugs such as protein agonists, antagonists, and inhibitors. Since antisense oligomers are classified as nucleotides, they are subject to attack by nucleases. In order to be antisense drugs resistant to degradation by nucleases, the structural modifications in the linkages, bases, and sugars to satisfy this requirement are considerable. We attempted in this study, to synthesize 16-mer antisenses with a modified linkage and adenosine. When studying on the three-dimensional structure of the oligomer, however, the existence of isomers may complicate the interpretation of the NMR data. Therefore, an attempt was made to eliminate the above problem, thus, two dimers were synthesized and their structural studies were carried out.
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.
Structural Study of Antisense Dimers,Modified Adenosine-Thymidine Phosphorothioate
JUNG, KYEONG-EUN,YANG, MIRIM,LEE, KWANGJUN,LIM, HONG,JUNG, JIHYUN,KOO. BONJUNG,JEONG, LAK SHIN,SHIN, DONG-HOON,LEE, CHUL-HOON,CHO, YOUL-HEE,LIM, YOONGHO 한국미생물 · 생명공학회 2000 Journal of microbiology and biotechnology Vol.10 No.6
Antisense molecules are structurally simple linear oligomers of nucleotides. They can recognize a complementary sequence by base pairing, therefore, antisense drugs composed of 15-16 bases are potentially useful, unlike drugs such as protein agonists, antagonists, and inhibitors. Since antisense oligomers are classified as nucleotides, they are subject to attack by nucleases. In order to be antisense drugs resistant to degradation by nucleases, the structural modifications in the linkages, bases, and sugars to satisfy this requirement are considerable. We attempted in this study, to synthesize 16-mer antisenses with a modified linkage and adenosine. When studying on the three-dimensional structure of the oligomer, however, the existence of isomers may complicate the interpretation of the NMR data. Therefore, an attempt was made to eliminate the above problem, thus, two dimers were synthesized and their structural studies were carried out.
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>
Jung, Kyeong Youl,Kim, Eun Joung,Kang, Yun Chan 한국공업화학회 2005 Journal of Industrial and Engineering Chemistry Vol.11 No.2
High-luminescent (Y,Gd)BO₃:Eu red phosphor particles were synthesized by spray pyrolysis and the morphology of these particles was improved by controlling the precursor solution to be sprayed. An investigation was also conducted into the effects that several codopants (In, Dy, Sm, Tm, and Pr) have on the photoluminescence intensity of (Y,Gd)BO₃:Eu particles under vacuum ultraviolet excitation. It was found that modifying the spray solution with NH₄OH improved the morphology of phosphor particles obtained after heat treatment. As a result, the rod-shaped (Y,Gd)BO₃:Eu particles obtained from the nitrate precursor solution in the spray pyrolysis were almost spherical. By varying the heat treatment temperature from 900 to 1200℃, the optimal temperature was found to be 1050℃ in terms of the luminescence efficiency and morphology of the (Y,Gd)BO₃:Eu particles prepared from the NH₄OH-modified precursor solution. Of the several codopants used, indium was the most effective at improving the photoluminescence intensity of (Y,Gd)_(0.95)BO₃:Eu_(0.05),M_(x) particles under vacuum ultraviolet excitation. Finally, the highest photoluminescence intensity was obtained when the indium content (X) was 0.001. The optimized (Y,Gd)_(95)BO₃:Eu_(0.05),In_(0.001) particles show a 6% higher luminescence intensity than do the commercial particles.