• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.4
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• pp.318-322
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• 2009

In this paper, to establish growth technology of ZnO:Al thin films at low temperature applied to photoelectronic devices, ZnO:Al were prepared by RF magnetron sputtering on glass substrate at room temperature using different RF power with subsequent annealing process at different temperature in $H_2$ ambient. The resistivity of hydrogen-annealed ZnO:Al thin film at temperature of $300^{\circ}C$ was reduced to $8.32{\times}10^{-4}{\Omega}cm$ from $9.44{\times}10^{-4}{\Omega}cm$ which was optimal value for as-grown films. X-ray photoelectron spectroscopy(XPS) revealed that improved electrical properties are ascribed to desorption of the negatively charged oxygen species from the grain boundary surfaces by the hydrogen annealing process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.326-329
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• 2003

When an electrokinetic process is applied to a HOC-contaminated soil, hybrid types combined with soil flushing, chemical oxidation, and bioremediation are generally used. Especially when the electrokinetic process is combined with bioremediation, the hybrid technology can solve several limits of bioremediation such as low microbial mobility, low soil temperature, and shortage of nutrients in subsurface circumstance. Because microbial surface is charged negatively, the microorganism moves from cathode to anode under electrical field. In this study, mixed culture mainly-consisted by Pseudomonas sp. was applied to remediate pentadecane-contaminated kaolinite with particle size less than 300${\mu}{\textrm}{m}$. This remediation system was named ‘electrokinetic bioaugmentation’ and consisted of model aquifer, electrode reservoirs, bioreactor, power supply, and pump. The mixed culture above 0.5 of optical density in bioreactor was supplied to two reservoirs and penetrated soil when the electric current was applied. To enhance the removal efficiency, the optimal medium composition, electric current, and voltage were investigated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.351-354
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• 2013

Thin-film transistors(TFTs) with silicon-zinc-tin-oxide(SiZnSnO, SZTO) channel layer are fabricated by rf sputtering method. Electrical properties were changed by different annealing treatment of dry annealing and wet annealing. This procedure improves electrical property especially, stability of oxide TFT. Improved electrical properties are ascribed to desorption of the negatively charged oxygen species from the surfaces by annealing treatment. The threshold voltage ($V_{th}$) shifted toward positive as increasing Si contents in SZTO system. Because the Si has a lower standard electrode potential (SEP) than that that of Sn, Zn, resulting in the degeneration of the oxygen vacancy ($V_O$). As a result, the Si acts as carrier suppressor and oxygen binder in the SZTO as well as a $V_{th}$ controller, resulting in the enhancement of stability of TFTs.

• Journal of the Korean Magnetic Resonance Society
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• v.4 no.2
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• pp.82-90
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• 2000

Photoinduced charge separation of alkylphenothiazines in molecular assemblies such as positively, negatively and neutrally charged micelle interface results in the paramagnetic phenothiazine cation radical. This was studied as a model system for the light energy conversion into chemical energy. The photoproduced phenothaizne cation radical was identified and its amount was quantized with electron spin resonance (ESR). The microenvironment of photoproduced cation radical was studied with pulsed-ESR. Such a charge separation is enhanced by the optimization of various structural factors of the molecular assemblies. The structural factors of molecular assemblies have focused on the interface charge, interface structure with different headgroups and interfacial perturbation by disolving interface active organic additives.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.152-152
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• 2003

The majority of the SKYBIO will be used in the treatment of water in food processing plants, swimming pools and cooling towers, in the manufacture fabric softeners in Australia. Most will eventually be released into domestic sewage system as a consequence of product use. The SKYBIO is not readily biodegradable (0% over 28 days), and is expected to have a low partition coefficient and high water solubility (285 g/L), all indicating that the material would be mobile in both aquatic and terrestrial compartment. The PEC/PNEC ratio for the aquatic environment is 56. This value is significantly greater than 1, indicating an immediate concern to the aquatic compartment. However as a consequence of it's cationic character, the SKYBIO will be expected to associate to negatively charged organic matter in soil and sediment.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.328-328
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• 2011

전기장 E와 자기장 B가 서로 수직으로 인가된 플라즈마에서 전자와 이온의 이동 현상은 이미 널리 알려져 있다. 그런데 최근 플라즈마 응용 산업의 발달에 따라 음이온을 포함한 플라즈마에서 나노미립자의 운동에 대한 해석이 필요하다. 특히 실리콘 박막의 에칭, 스퍼터링, PECVD 등의 공정에 사용되는 실란 플라즈마에서 음이온의 발생에 따른 오염은 주요한 문제가 된다. 따라서 본 연구에서는 이러한 음이온을 제거하기 위해 E${\times}$B 드리프트 운동을 이론적으로 계산 하였다. 결과적으로 음으로 대전된 나노미립자는 E${\times}$B 드리프트 운동의 반대 방향으로 이동 하였고, 드리프트 속도는 자속밀도가 증가함에 따라 함께 증가됨을 보였다. 따라서 서로 수직으로 인가된 전자기장에 의한 E${\times}$B 드리프트 운동을 통해 음이온을 방전 공간에서 제거할 수 있음을 알 수 있었다.

• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.353-355
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• 2010

Poly(methyl methacrylate) (PMMA) particles were prepared by soap-free emulsion polymerization of MMA in the presence of a cationic initiator, 2,2'-azobis(2-methylpropionamidine) (AIBA). The Stober method has been adopted to coat silica on the surface of these cationic particles. Negatively charged silica precursors were coated onto cationic particle surfaces by electronic interaction. During the coating process, hollow particles were directly obtained by dissolution of PMMA.

• Journal of Plant Biology
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• v.31 no.2
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• pp.155-164
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• 1988

The rapid senescence of detached Chinese cabbage leaf discs in darkness is first manifested by a sharp rise in malondialdehyde content (indicated by distruption of membrane structure), then by a rise in peroxidase activity and a decrease in catalase activity, and ultimately by chlorophyll degradation. These changes in parameters besides the catalase activity during senescence were delayed by application of spermidine. Especially, 10-4M spermidine almost completely arrested chlorophyll degradation after incubaton over 5 days. Spermidine reduced the amount of ethylene produced by senescing leaf discs. Additionally, it also reduced IAA-induced ethylene production. Calcium ion (1mM, 10mM) supplied together with the spermidine diminished the spermidine action, indicating probable involvement of an initial ionic attachment mechanism. These results suggest that spermidine can be used as an anti-senescence agent for plants and that this agent may stabilize membrane structure through interaction with the negatively charged loci on the membrane and exert the influence during senescence.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.06a
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• pp.93-104
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• 1997

The objective of this study is to develop a method to reduce arsenic concentrations in contaminated water. This work is also aimed at increasing the specificity of membrane separation processes. Arsenic in contaminated waters is often present in the form of negatively charged oxyanions. These are relatively small molecules which cannot be separated directly by ultrafiltration. Oxyanions can be captured by polyelectrolytes and separated by ultrafiltration. Results will be presented on the use of two polyelectrolytes; polyethylenimine (PEI) and poly-diallyl dimethyl ammonium chloride (DADMAC) at various feed concentrations. A semi-continuous process utilizing PEI in a circulation loop was tested. The restfits indicate that better than 99.6 % recovery (permeate concentration < 0.001 $\mu$g/L) can be achieved based on an initial arsenic concentration of 300 $\mu$g/L. The results indicate that this treatment method is suitable as a main treatment process for drinking water or a polishing step after arsenic precipitation.

• Journal of Plant Biology
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• v.36 no.1
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• pp.19-27
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• 1993

Effects of polyamines on DNA synthesis were studied in synchronized culture of Nicotiana tabacum L. When DFMO and DFMA, inhibitors of ornithine decarboxylase and arginine decarboxylase, respectively were initially applied to the cells, the polyamine contents were rapidly dropped and [methyl-3H] thymidine incorporation into DNA was markedly reduced during the early stage of culture period. Inhibition of DNA synthesis, however, was partially reversed when these inhibitors were applied simultaneously with putrescine. In addition, exogenous administration of putrescine also increased the DNA synthesis during the all over the culture period. In vitro activity of DNA polymerase from Nicotiana tabacum L. was promoted by increasing concentrations of polyamines in the reaction mixture. Maximal activity was shown at 5 mM putrscine, 0.5 mM spermidine and spermine, respectively. Lack of Mg2+ ion in the reaction buffer resulted in an inhibition of the enzyme activity by about 30%. The inhibition could not be completely reversed by application of polyamines at optimal concentrations. These results suggest that polyamines promote the DNA synthesis in vivo and in vitro by stabilizing the DNA-helix upon binding to negatively charged groups on DNA or increasing the activity of DNA polymerase in Nicotiana tabacum L.