• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.292-300
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• 2006

In order to improve energy efficiency in the dilute trichloroethylene removal using the nonthermal plasma process, the barrier discharge treatment combined with manganese dioxide was experimentally studied. Reaction kinetics in this process was studied on the basis of final byproducts distribution. Decomposition efficiency was improved to about $99\;\%$ at the specific energy of 40 J/L with passing through manganese dioxide. C=C ${\pi}$ bond cleavage of TCE substances gave DCAC, which has the single bond of C-C through oxidation reaction during the barrier discharge plasma treatment. Those DCAC were broken easily in the subsequent catalytic reaction due to the weak bonding energy about $3{\sim}4\;eV$ compared with the double bonding energy in TCE molecules. Oxidation byproducts of DCAC and TCAA from TCE decomposition are generated from the barrier discharge plasma treatment and catalytic surface chemical reaction, respectively. Complete oxidation of TCE into COx is required to about 400 J/L, but $CO_2$ selectivity remains about $60\;\%$.

• 한국표면공학회지
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• 제41권6호
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• pp.308-311
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• 2008

Oxide layers were prepared on Al2021 alloys substrate under a hybrid voltage of AC 200 V (60 Hz) combined with DC 260 V value at room temperature within $5{\sim}60\;min$ by plasma electrolytic oxidation (PEO). An optimized aluminate-fluorosilicate solution was used as the electrolytes. The surface morphology, thickness and composition of layers on Al2021 alloys at different reaction times were studied. The results showed that it is possible to generate oxide layers of good properties on Al2021 alloys in aluminate-fluorosilicate electrolytes. Analysis show that the double-layer structure oxide layers consist of different states such as ${\alpha}-{Al_2}{O_3}$ and ${\gamma}-{Al_2}{O_3}$. For short treatment times, the formation process of oxide layers follows a linear kinetics, while for longer times the formation process slows down and becomes a steady stage. During the PEO processes, the average size of the discharge channels increased gradually as the PEO treatment time increased.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.502-507
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• 2007

The oxidation treatment of several carbon materials with a sodium chlorate and 70 wt.% of nitric acid, combined with heat treatment, were attempted to achieve an electrochemical active material with a larger capacitance. Among pitch, needle coke, calcinated needle coke and natural graphite, the structure of needle coke and calacinated needle coke were changed to the graphite oxide structure with the expansion of the inter-layer. On the other hand, the calcinated needle coke after oxidation and heating at $200^{\circ}C$ has exhibited largest capacitance per weight and volume of 29.5 F/g and 24.5 F/ml at the two-electrode system in the potential range of 0 to 2.5 V. The electrochemical performance of the calcinated needle coke was discussed with the phenomenon of the electric field activation and the formation of new pores between the expanded inter-layer at first charge.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.552-553
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• 2005

In order to improve energy efficiency in the dilute trichloroethylene removal using the nonthermal plasma process, the barrier discharge treatment combined with manganese dioxide was experimentally studied. Reaction kinetics in this process was studied on the basis of final byproducts distribution. Decomposition efficiency was improved to about 99% at the specific energy 40J/L with passing through manganese dioxide. C=C $\pi$ bond cleavage in TCE gave DCAC (single bond, C-C) through oxidation reaction during the barrier discharge plasma treatment. Those DCAC were broken easily in the subsequent catalytic reaction due to the weak bonding energy about 3 ~ 4 eV compared with the double bonding energy in TCE molecules. Oxidation byproducts of DCAC and TCAA from TCE decomposition are generated from the barrier discharge plasma treatment and catalytic surface chemical reaction, respectively. Complete oxidation of TCE into $CO_X$ is required to about 400J/L.

• Bulletin of the Korean Chemical Society
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• 제12권2호
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• pp.219-224
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• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.

• 한국해양바이오학회지
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• 제7권1호
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• pp.1-10
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• 2015

Bio diesel has advantages to reduce GHG(Greenhouse Gas) compare with the fossil fuel by using oil comes from plant/animal sources and even waste such as used cook oil. The diversity of energy feeds brings the positive effects to secure the national energy mix. In this circumstance, micro-algae is one of the prospective source, though some technical barriers. We analyzed the bio diesel which was derived from Dunaliella tertiolecta LB999 through the BD100 quality specifications designated by the law. From that result, it is revealed that the oxidation stability is one of the properties to be improved. In order to find the reason for low oxidation stability, we analyzed the oxidation tendency of each FAME components through some methods(EN 14111, EN14112, EN16091). In this study, we could find the higher double bond FAME portion, the more oxidative property(C18:1${\ll}C18:3$) in bio diesel and main unsaturated FAME group is acted as the key component deciding the bio diesel's oxidation stability. It is proved experimentally that C18:3 FAME are oxidized easily under the modified accelerated oxidation test. We also figure out low molecular weight hydrocarbon and FAME were founded as a result of thermal degradation. Some alcohol and aldehydes were also made by FAME oxidation. In conclusion, it is necessary to find the way to improve the micro-algal bio diesel's oxidation stability.

• Journal of Photoscience
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• 제9권2호
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• pp.488-490
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• 2002

DNA photodamage mediated by photosensitizers are believed to play an important role in solar UVA carcinogenesis. We investigated the relationship between the DNA-damaging abilities of photoexcited xanthone analogues (as photosensitizers) and their highest occupied molecular orbital (HOMO) energies. DNA damage was examined using /sup 32/P-labeled DNA fragments obtained from the p53 tumor suppressor gene. These compounds induced DNA photodamage in a similar manner, and the extents of DNA damage were following order: xanthone> thioxanthone > acridone. Photoexcited xanthone caused nucleobase oxidation specifically at 5'-G of GG sequence in double-stranded DNA. An oxidative product of 2'-deoxyguanosine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), was detected, and the amount was decreased by DNA denaturation. These findings suggest that photoexcited xanthone generates 8-OHdG at 5'-G of GG in double-stranded DNA through electron transfer. The calculated HOMO energies of these photosensitizers decreased in the following order: xanthone> thioxanthone > acridone. This study has demonstrated that DNA-damaging abilities of these photosensitizers increased exponentially with an increase in their HOMO energies.

• 대한화학회지
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• 제35권1호
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• pp.59-63
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• 1991

카나비노이드의 할로겐화 반응은 metal halide와 함께 18-crown-6 존재하에 m-chloroperbenzoic acid에 의해 좋은 수득률의 산화반응이 일어났다. 이 반응계에서는 할로겐화 반응이 방향족 고리에만 선택적으로 일어났다.

• Bulletin of the Korean Chemical Society
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• 제9권1호
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• pp.13-15
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• 1988

Several types of resocinols have been monobrominated in the ring in good yields with sodium bromide in the presence of 18-crown-6 on oxidation with m-chloroperbenzoic acid. Monoiodination takes place with 2'-(1-methylcyclohexen-3-yl)-5-(1,1-dimethylheptyl )-resocinol when sodium iodide is employed. This new reagent system, MX/18-crown-6/m-CPBA (M =$K^+, Na^+, X = Br^-, I^-X$ ), effects the regiospecific halogenation of activated aromatic ring over olefinic double bond.

• Progress in Superconductivity
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• 제10권2호
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• pp.99-102
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• 2009

We report our development of the fabrication process of sub-micron scale $Al-AlO_x-Al$ tunnel junction by using electron-beam lithography and double-angle shadow evaporation technique. We used double-layer resist to construct a suspended bridge structure, and double-angle electron-beam evaporation to form a sub-micron scale overlapped junction. We adopted an e-beam insensitive resist as a bottom sacrificing layer. Tunnel barrier was formed by oxidation of the bottom aluminum layer between the bottom and top electrode deposition, which was done in a separate load-lock chamber. The junction resistance is designed and controlled to be 50 $\Omega$ to match the impedance of the transmission line. The junctions will be used in the broadband shot noise thermometry experiment, which will serve as a link between the electrical unit and the thermodynamic unit.