• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1053-1056
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• 2003

Progress in light emitting materials is presented. New polymers based on the Spiro concept show encouraging properties in electroluminescence performance and lifetime. The spiro-polymers can be tailor made to fit the RGB color requirements of a full color display. This class of materials showed recently very promising performance for white emission as well. They are readily soluble, show excellent thermal stability and can be processed by printing or through simple synthetic modification by photolithography technology.

• 한국환경보건학회지
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• 제5권1호
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• pp.21-24
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• 1978

This study was conducted to find out the co-operative effect of antioxidants (butyl hydroxy anisol, dibutyl hydroxy toluene, propyl gallate, dl-$\alpha$-tocopherol) and organic acid (citric acid, tartaric acid, succinic acid) on the stability of soybean oil by active oxygen method. The results obtained were summarized as follows: 1. When antioxidants and organic acid were used together, the antioxidants activity was more strong than antioxidants were used only. 2. The co-operative effect of citric acid for antioxydants was the strongest whereas succinic acid was the weakest. 3. The co-operative effect of phenolic antioxydants for organic acid was more strong than dl-$\alpha$-tocopherol.

• Macromolecular Research
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• 제11권3호
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• pp.194-197
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• 2003

A new 2,5-di(t-octylphenoxy) group substituted poly(p-phenylenevinylene) derivative was synthesized by Gilch polymerization. The obtained polymer was characterized by NMR, FT-IR, and chemical analysis and completely soluble in common organic solvents. The polymer showed good thermal stability with T$_{g}$ of 105$^{\circ}C$. The polymer dissolved in chloroform showed maximum emission at 514 nm with a shoulder peak at around 560 nm. The EL spectrum of the ITO/PEDOT/TOP-PPV/Al device was observed maximum emission at 545 nm with a shoulder peak at around 585 nm.m.

• Macromolecular Research
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• 제8권3호
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• pp.142-146
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• 2000

Hyperbranched poly(ether sulfone) analogs with the 1,3,5-s-triazine moiety were prepared by the direct polymerization of AB$_2$type monomer, 2,4-bis(4-hydroxyphenyl)-6-(4-(4-(4-fluorobenzenesulfonyl)phenoxy)phenyl)-1,3,5-s-triazine (3). The selective reactivity of three chlorine atoms on cyanuric chloride toward nucleophiles provides an efficient route for the systematic synthesis of AB$_2$type triazine monomers and their hyperbranched polymers. The triazine rings influenced the structural and material characteristics of these hyperbranched polymers. The hyperbranched poly(ether sulfone) analog4 showed a glass transition at 295$^{\circ}C$. and was soluble in THF, 1,4-dioxane, and DMSO. An excellent thermal stability of polymer 4 was exhibited by a TGA analysis, which showed that 5% weight loss occurred at 480$^{\circ}C$.

• 한국응용과학기술학회지
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• 제20권1호
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• pp.27-32
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• 2003

The core-shell latex particles were prepared by sequential emulsion polymerization of alkyl methacrylate and styrene(ST) by using an water-soluble initiator(APS) after preparing monomer pre-emulsion in the presence of an anionic surfactant(SDBS). In organic/organic core-shell polymerization, the pre-emulsion method, which minimized required quantity of sulfactant, has been used to increase the conversion rate and the stability of core-shell latex particles as well as to reduce the formation of secondary particle that cause problems of soap-free emulsion during shell polymerization. We used several methods to observe the core-shell structure. The core-shell structure was studied by measuring pH change during hydrolysis by NaOH, glass transition temperature($T_g$) by differential scanning calorimeter(DSC), morphology of latex by transmission electron microscope(TEM) and change of particle size and distribution by a particle analyzer.

• 한국식물병리학회지
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• 제10권4호
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• pp.277-283
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• 1994

An antimicrobial chitinase was purified from grapefruit extract and its properties were characterized. The chitinase was purified with a single step chromatography on regenerated chitin affinity gel column. The molecular weight of the purified chitinase was 29 kDa. The grapefruit extract contained the chitinase protein more than 50% of its total soluble proteins measured by coomassie stained protein bands. When the purified chitinase was incubated with polymers of N-acetylglucosamine (NAG), such as mycelia of Fusarium oxysproum and swollen chitin, they were degraded to oligosaccharides, and the oligosaccharides were then further hydrolyzed by the same enzyme to monomer and dimer of NAG. This result suggests that the chitinase contained both endo- and exo- chitinase activities. The chitinase was stable to heat and pH treatment; its activity was not diminished by the heat treatment upto 7$0^{\circ}C$ for 1 hr, and it showed a pH stability in the range of pH 4.0 to 12.0.

• 미생물학회지
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• 제21권1호
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• pp.27-35
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• 1983

The stoichiometry between the consumption of CO and $O_2$ and the production of $CO_2(2CO+O_2{\rightarrow}2CO_2)$) showed that Pseudomonas carboxydohydrogena grows as a typical aerobic CO oxidizer with CO. The optimal concentration of CO for growth was found to be 30% in gas mixture with air. The initial buffer concentration of the culture medium did not affect the growth of this bacterium. P. carboxydohydrogena is an obligate aerobe and dose not use nitrate as a terminal electron acceptor. The CO dehydrogenase is an inducible and soluble enzyme. The reaction rate and stability were maximal at pH7.5, and the Arrhenius plot revealed an activation energy of 37.7kJ/mol (9.0 Kcal/mol). The crude enzyme used methylene blue, thionin, and toluylene blue as electron acceptors for the oxidation of CO to $Co_2$ under anaerobic conditions. It was found that water must be the source of the second oxygen atom for CO oxidation.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2006년도 춘계학술발표회 논문집
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• pp.180-181
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• 2006

The hydrolysis of some vinylsulfonyl (VS) typed reactive dyes were investigated at the pH, temperature and other experimental conditions. The hydrolytic behaviour, especially, stability in various pH value, of the water soluble reactive dyes are examined. In neutral and acid condition, mother dyes are a quite stable. Other hand, it was found that dimerization and decomposition for these dyes were estimated in an aqueous alkaline medium. These alkaline hydrolysis behaviour was monitored by the high performance liquid chromatography.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 가을 학술발표회 논문집
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• pp.169-170
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• 2003

There was little development in transparent conductive polymer films and their limited studies have been mainly focused on polymer films coated by water-soluble PEDOT doped with the polymeric counteranion poly(4-styrenesulfonate) (PEDOT-PSS)[1-3]. However PEDOT-PSS as coating material has some difficulties because of high viscosity and low solubility in organic solvent except for in water. In this study, in order to extend practical applications of PEDOT and to prepare conductive PC films, we tried to prepare PEDOT-coated PC films and investigated their conductivity and thermal stability. (omitted)

• Transactions on Electrical and Electronic Materials
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• 제13권6호
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• pp.317-321
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• 2012

Poly[4,4'(3,3')-biphenylenevinylene-alt-2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene], 4,4'(3,3')-PBPMEH-PPV, and poly[4,4'(3,3')-biphenylenevinylene-alt-N-ethylhexyl-3,6-carbazolevinylene], 4,4'(3,3')-PBPCAR-PPV, of varying effective conjugation lengths, were synthesized by the well-known Wittig condensation polymerization between the appropriate biphenyl diphosphonium salts and dialdehyde monomers such as carbazole or dialkoxyphenyl dialdehyde. The conjugation lengths of the polymers were controlled by biphenyl linkages (4,4' or 3,3'). The resulting polymers were highly soluble in common organic solvents and exhibited good thermal stability up to $300^{\circ}C$. The synthesized polymers showed UV-visible absorbance and photoluminescence (PL) in the ranges of 314-400 nm and 430-507 nm, respectively. Carbazole and 3,3'-biphenyl containing 3,3'-PBPCAR-PPV showed a blue PL peak at 430 nm. A single-layer light-emitting diode was fabricated in a configuration of ITO/polymer/Al. Electroluminescence (EL) emission of 3,3'-PBPCAR-PPV was shown at 455 nm.