• Bulletin of the Korean Chemical Society
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• v.6 no.3
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• pp.138-140
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• 1985

Hydroxylation of anisole with $H_2O_2$ was investigated by employing Fe(III) ion and N-dodecyl-3,4-dihydroxybenzamide (DDHB) as a catalyst. The study was aimed at obtaining an insoluble catalyst with a long catalytic life, in view of the inactivation of the catechol portion of the catalyst during the reaction. The rate of decomposition of $H_2O_2$ under various conditions indicated that the reaction proceeds through the catalytic participation of $Fe(III){\cdot}DDHB$. Yield of the hydroxylation products under various conditions revealed that $Fe(III){\cdot}DDHB$ is not inactivated during the reaction.

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.193-197
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• 1994

Due to possibility of visual observation of phase transformations and processes during solidification, the transparent binary alloy models are important in materials and metallurgical sciences. As such, phase diagram, linear velocity of crystallization, microstructure and spectral behaviour of binary organic systems of benzidine with resorcinol and catechol involving formation of addition compound with congruent melting point have been studied. While their phase diagrams show the formation of two eutectics and a 1:2 (B:RC, B:CT) addition compound in each case, the crystallization data obey the Hillig-Turnbull equation. The microstructural investigations give the characteristic morphology of the eutectics and the addition compounds, the spectral studies suggest intermolecular hydrogen bonding between two components forming the molecular complex.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.212-217
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• 1998

The electrochemistry and valence tautomerism of CoⅢ(N-N)(SQ)(Cat), [N-N=N,N,N',N'-tetramethylethylenediamine (TMEDA); SQ=3,5- or 3,6-di-tert-butyl-semiquinone, Cat=3,5- or 3,6-di-tert-butyl-catechol], have been investigated by spectroscopic, electrochemical, spectroelectrochemical methods in nonaqueous solvents under anaerobic condition. The transition temperature between tautomers is dependent upon the donation effect of substituted quinone ligand and solvent. It increases with the increase of donation effect of solvent and quinone ligand. CoⅢ(TMEDA)(SQ)(Cat) is reduced to [CoⅡ(TMEDA)(SQ)(Cat)]-, and then reduces to [CoⅡ(TMEDA)(Cat)2]2-. CoⅢ(TMEDA)(SQ)(Cat) is oxidized to [CoⅢ(TMEDA)(SQ)2]+, but the stability of the oxidized form in DMF is dependent upon the solution temperature. With the increase of solution temperatrue the oxidized form may be converted to [CoⅡ(TMEDA)(SQ)(BQ)]+ by intramolecular electron transfer from SQ ligand to CoⅢ.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.259-260
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• 2022

In this study, as part of a study to solve the problem of aggregate supply and demand, blast furnace slag fine aggregate and ferronickel slag fine aggregate were used as substitutes for natural fine aggregate, and a bioinspired polymer, a catechol-functionalized chitosan, was used instead of the mixing water.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.257-258
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• 2022

In this study, as a part of the study to alleviate the durability degradation due to low tensile performance and cracking of concrete, two kinds of catechol functional chitosan (Cat-Chit) were replaced at a ratio of 5, 10, 15, 20% as a mixed water substitute to evaluate the fluidility and strength characteristics of mortar.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.70-78
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• 1998

Dissipation, adsorption and desorption of oxadiazon were examined in two soils containing different amounts of soil organic matter. In addition, reactivity of oxadiazon with humic monomers was searched to clarify binding mechanism of oxadiazon to soil organic matter in the presence of a laccase of Myceliophthera thermophila. Half lives of oxadiazon were 38 days in Soil I and 45 days in Soil II. Freundlich constant, k values of fresh soils were higher than those of oxidized soils. Adsorption rates of oxadiazon were increased 17.1% in Soil I and 9.3% in Soil II in the presence of a laccase but no significant increase was observed in oxidized soils. Desorption rates of oxadiazon in fresh soils were lower than those in oxidized soils. Desorption rates of adsorbed oxadiazon in soils addes with the enzyme were not changed in oxidized soils but decreased in fresh soils. The herbicide oxadiazon alone underwent no transformation by a laccase but in the presence of catechol, guaiacol and gallic acid as humic monomer, transformation rates of it were from 20% to 24%.

• Journal of Life Science
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• v.19 no.5
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• pp.659-663
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• 2009

Bacterial stain 3Y was isolated from a site that was contaminated with diesel for more than 15 years. The strain could grow on various petroleum using hydrocarbons as the sole carbon source. The strain grew not only on aliphatic hydrocarbons but also on aromatic hydrocarbons. 3Y grew on aliphatic petroleum hydrocarbons hexane or hexadecane, and aromatic petroleum hydrocarbons BTEX, phenol, biphenyl, or phenanthrene. The strain showed aromatic ring dioxygenase and meta-cleavage dioxygenase activities as determined by tests using indole and catechol. Aromatic ring dioxygenase is involved in the initial step of biodegradation of aromatic hydrocarbons while meta-cleavage dioxygenase catalyzes the cleavage of the benzene ring. Based on a nucleotide sequence analysis of its 16S rRNA gene, 3Y belongs to the genus Sphingomonas. A phylogenetic tress was constructed based on the nucleotide sequences of closest relatives of 3Y and petroleum hydrocarbon degrading sphingomonads. 3Y was in a cluster that was different from the cluster that contained well-known sphingomonads. The results of this study suggest that 3Y has the potential to cleanup oil-contaminated sites. Further investigation is warranted to optimize conditions to degrade petroleum hydrocarbons by the strain to develop a better bioremediation strategy.

• Journal of Korean Society of Forest Science
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• v.85 no.3
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• pp.372-380
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• 1996

This study was carried out to study the resistant substances to pine needle gall midge and seasonal variation of phenolic compounds in pine needles among susceptible and resistant species to pine needle gall midge. Free and water soluble phenolic compounds contained in pine needles showed seasonal variations among pine species. But, catechol, vanillic acid and syringic acid including phenolic compounds showed no variation between pine species, even the amount of those component varied by the seasons. Salicylic acid in pine needles showed 140ppm in Pinus virginiana, 35ppm in Pinus thunbergii and 72ppm in hybrid pine, Pinus thunbergii${\times}$P. virginiana, but traces in Pinus densiflora on May and June, hatching season in larvae of pine needle gall midge. There was high level of salicylic acid in resistant species to pine needle gall midge but traces in susceptible species. As our previous researches, the necrosis rate of larvae of pine needle gall midge showed high level on the solution of phenolic compounds extracted from needles of P. virginiana and salicylic acid, and there was no gall formation in P. virginiana, so that salicylic acid in pine needles seems to have relation with those results. Therefore, it is estimated that salicylic acid is resistant substance to pine needle gall midge.

• Journal of Korean Society of Forest Science
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• v.50 no.1
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• pp.49-55
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• 1980

Monoterpenes, phenolic substances, growth substances and total nitrogen from normal needles and infested needles attacked by Thecodiplosis japonensis were compared for Pinus densiflora, Pinus thunbergii and Pinus rigida. The results obtained in this study were as follows: 1. Major monoterpene components in P. densiflora needles were ${\beta}$-phellandrene, ${\alpha}$-pinene and those in P. rigida needles were ${\beta}$-pinene and ${\alpha}$-pinene. In P. rigida resistant to this insect, infested needles showed higher ${\alpha}$-pinene, ${\beta}$-pinene and myrcene but lower camphene, limonene and ${\beta}$-phellandrene than normal needles. 2. Orcinol, catechol ferulic acid, salicylic acid and five unknowns were detected in P. rigida needles whereas orcinol, catechol, ferulic acid and four unknowns in P. densiflora needles. 3. Tryptophan, a precursor of IAA, was detected in larvae and also in gall tissues of both P. densiflora and P. thunbergii needles. This fact shows that growth substances may involve in gall formation by Thecodiplosis japonensis. 4. Total nitrogen contents per unit needle weight were neither significantly different between P. densiflora and P. rigida, nor between normal and infested needles.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.920-924
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• 2004

The beneficial effects of green and fermented tea are generally attributed to some antioxidant activities including superoxide dismutase (SOD)-like ability and scavenging activity originated from their phenolic compounds and flavonoids. Content of total flavonoid of green tea $(413.3\;{\mu}g/g)$ was similar to those of fermented tea $(405.7\;{\mu}g/g)$. Content of total phenol of green tea $(46.8\;{\mu}g/g)$ was higher than those of fermented tea $(23.5\;{\mu}g/g)$. Major catechin compounds of hot water extract in green tea was EGCG, including EGC, Gc, catechin and catechol. EGCG was not detected .in fermented tea. SOD-like ability was increased in proportional to added concentration of hot water extract. The scavenging activities of hydroxyl radical at $3000\;{\mu}g/ml$ of green and fermented teas were found up to $60\%$. Hot water extract of green tea was more effective in scavenging activity than that of fermented tea.