• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.210-215
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• 2022

Two types of lignin materials with a different surface ionic character were used and polypyrrole layer was introduced on the lignin surface to obtain polypyrrole@lignin and polypyrrole@lignosulfonate composites using a simple chemical oxidation polymerization, reported in a previous article. Polypyrrole was effectively prepared regardless of the lignin type and the resulting composites were investigated using scanning electron microscope (SEM), cyclic voltammetry (CV), and impedance analysis. SEM and CV results showed that the obtained composites retained stable electrochemical properties after introduction of polypyrrole on the lignin surface. Impedance analyses showed that the surface properties of composites were dependent on lignin characteristics. In addition, the composites were embedded in agarose, an gelifying agent, to obtain conductive gels. It was found that the conductive gels possessed an electrical conductivity and also retained stable electrochemical properties, which indicated that the conductive gels might be useful for some applications.

• Journal of the Korean Geosynthetics Society
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• v.22 no.1
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• pp.1-7
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• 2023

This study has utilized self-assembled monolayers technology to improve electrical property of graphene-oxide, which has been seperated graphine powder through a chemical exfoliation. Aluminum sulfate (Al₂(SO₄)₃) was applied on graphene-oxide as a reactant, and the fundamental research was carried out to apply on the self-sensing of cement-based construction structures. Electric resistance measurement result has shown that cement-composites with GO and Al-GO can be used as a conductor, electric resistance of GO and Al-GO contained composites improved by 10.2% and 15.9% respectively when compared to the standard cement-composite. Microstructure analyzation shown the formation of Al(OH)₃ gel when Al-GO was added, which is speculated to result the smooth flow of current by improving the density of cement-composite. This implies that graphene-oxide has a possibility to be utilized as smart building materials and construction structure itself rather than just a structure.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.21-26
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• 1983

As a series of studios on the suitability as a second intermediate host of Clcnorchis sinensis, the wormicidal effects of mucus from epidermis of Cyprinus carpio nudus were observed. The results obtained were sumlnarized as follows : On the silica gel thin layer chromatography with the greenisll yellow supernatant in acetone: benzene110:90 as carrier, seven spots were observed in iodine chamber. The spot of Rf. 0.225 value among them disclosed the strongest wormicidal effect on the cercaria, the encysted metacercaria, and the adult of C. sinensis. hfeanwhile, no seasonal variations were found in Rf. values and effect of the wormicidal fractions. The wormicidal materials in epidermal mucus of C. carpio nudes and Carassius carassius were compared in their effect, and the former was Inore effective killing substance than the latter. It seemed that C. carpio nodus could not be proper intermediate host of C. sinensis according to results of the present study, in addition to our previous observation results.

• Proceedings of the Membrane Society of Korea Conference
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• 1992.04a
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• pp.60-60
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• 1992

알루미나 분리막이 세라믹 분리막의 연구개발 초기단계부터 많은 사람들에 의해 연구되어온 반면, TiO$_2$ 및 ZrO$_2$ 분리막에 관한 연구는 상대적으로 관심이 적었고 따라서 그 내화학성및 투과특성의 우수함이 밝혀진 것도 최근의 일이다. TiO$_2$ 및 ZrO$_2$ UF 분리막의 제조방법으로는 $Al_2O_3$ 의 경우와 마찬가지로 대부분 졸-겔 공정이 이용되고 있다.

• Transactions on Electrical and Electronic Materials
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• v.17 no.3
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• pp.178-181
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• 2016

In this study a coating experiment was performed to fabricate blue light cut films, which represent a 390~430 nm cut off rate of more than 40% and a transmittance rate of more than 90%, using a roll-to-roll nano micro coating system. The study also analyzed the characteristics of the blue light cut films. Thus, the hardness, which is more than 3H, is ensured through fabricating films using a Sol-Gel process that will determine the proper hardness level. Also, the experiment shows excellent results by cutting blue light through a mixing blue light powder.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3417-3422
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• 2012

A new method for the construction of 3-aminoindole nucleosides of 2-acetamido-2-deoxy-D-glucose based is presented. Nitration and acetylation of the indole nucleosides by acetic anhydride-nitric acid mixture followed by reduction using silver catalyst (SNSM) impregnated on silica gel, afforded the corresponding amino indole nucleosides. The nucleosides were tested for antiviral activity against hepatitis B virus (HBV) to show different degrees of antiviral activities or inhibitory actions.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.105-108
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• 2002

Polyimide-epoxysilane (coupling agent) composites were reacted with oligomeric PDMS, a condensation product of difunctional silane, by a sol-gel process and were then dried into films. And then, the surface, mechanical, and electric properties were measured. The study showed that PDMS existed in the polyimlde matrix by the use of FT-IR. In the mechanical properties, the maximum elongation and toughness was increased in the polyimide with silane-groups. But the maximum tensile strength was slightly decreased. And the intensive dispersion of the silane-groups on the surface of polyimide was ascertained through XPS measurement. In the electric properties, AC break down voltage was increased by increasing the amount of difunctional silane. This experiment showed that PDMS added polyimide had better mechanical and electric properties than classical materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.39-42
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• 1995

In this study, PLZT thin films prepared by Sol-Gel method were deposited on ITO glass by spin coating and cryatallized at 750$^{\circ}C$ for 5 min by RTA in oreder to investigate their electrical and optical properties. Although thin film experieneced narrowing their hysteresis loops with increasing La content, E$\sub$c/ and P.sub r/ were higher for thin film than for bulk materials. $\varepsilon$$\sub$r/ and optical transmittance increased with increasing La content.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.57-58
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• 2000

Production of dye-decolorizing enzyme was investigated with the cultivation of Geotrichum candidum Dec1 (abbreviated to Dec1) using molasses as a cheap raw materials. Molasses was found to stimulate the enzyme production as well as a role of carbon source, because the production increased with molasses content up to 50 g/L. However, the severe inhibition of dye-decolorizing enzyme activity was observed even at low concentration of molasses 10 g/L when purified decolorizing peroxidase was used. Its inhibitory effect was reduced through the cultivation of Dec1. The fractions of molasses separated by a gel chromatography showed the different degrees of inhibition. As a way to reduce the inhibitory effect, the dilution of culture broth was examined, and the total decolorizing activity for Reactive blue 5 increased 7 times as much as that of original culture broth by 30 times dilution. On the basis of result, we proposed a process scheme which can fully utilize both positive and negative effect of molasses in dye-decolorizing process using molasses.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.644-647
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• 2003

Materials currently used as an injectable bulking agent in the dermatologic and urologic fields revealed several drawbacks such as particles migration, inflammatory reaction, allergic reaction, rapid volume shrinkage, and necessity of a donor site. In this study, we have developed injectable biomaterial comprising poly (DL- lactide-co-glycolide)(PLGA) and hyaluronic acid gel to overcome these problems. PLGA is a biocompatible synthetic material and hyaluronic acid is a common substance found in living organisms. We examined the feasibility of injection through needle and tested biocompatibility in animal model. After transplantation, injected sites and distant organs were examined histologically to verify a new tissue formation, inflammation, and particles migrations. Injected volume was maintained approximately 80 percent for 2 months. Results demonstrated that the developed material was injectable through various gauges of needles and induced a new bulking tissue formation without serious inflammatory reaction.