• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.452-460
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• 1991

The chemical evidence for involvement of singlet oxygen during photoirradiation for 2-ethylanthracene [2-EA] and 9-phenylanthracene [9-PA] was based on the rapid decomposition of 1,3-diphenylisobenzofuran [DPBF] in methanol-water mixture and aqueous CTAB, and SDS micellar solutions. The average microenvironmental polarities of 2-EA and 9-PA were estimated by UV spectroscopic characteristics sensitive to the polarity of solvent. When 2-EA and 9-PA were solubilized in aqueous CTAB, SDS and Brij 35 solutions, their average microenvironmental polarities were polar, and their microenvironmental polarity parameter showed little dependence on the ionic properties of the micelles. The average microenvironmental polarity of 2-EA was similar to the polarity of 40% (w/w) aqueous ethanol, and that of 9-PA was similar to the polarity between 30 and 40% (w/w) aqueous ethanol. It was found that the greater part of these species might be distributed at the surface of micelles when they were solubilized in aqueous micellar solutions. The methanol-water mixture solution appeared to have characteristics more favorable for photooxidation reaction than aqueous micellar solutions.

• Applied Chemistry for Engineering
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• v.4 no.3
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• pp.474-481
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• 1993

The infinite dilution activity coefficients(${\gamma}{\infty}$) of nonpolar and polar solutes have been determined in different solvents at temperature between 60 and $100^{\circ}C$ by using gas chromatography. The $ln{\gamma}{\infty}$ values of nonpolar solutes(alkanes, cyclohexane, benzene, toluene and $CCl_4$) were linearly increased as 1/T in the nonpolar solvent (n-octadecane) and the polar solvent(n-hexadecyl alcohol) systems and the $ln{\gamma}{\infty}$ values at the constant temperature were increased with the number of carbon atoms of solute molecule. For the polar solutes(alcohols, esters and ketones) and the weak polar solvent(di-2-ethyl adiphate and di-2-ethylhexyl sebacate) systems, the relations of $ln{\gamma}{\infty}$ vs. 1/T were found to be curved with increased slope, and the $ln{\gamma}{\infty}$ values at constant temperature were linearly diminished as increasing the number of carbon atoms of solute molecule. For the polar solutes(alcohols, esters and ketones) and the strong polar solvents(triphenyl phosphate and tricresyl phosphate)systems, the relations of $ln{\gamma}{\infty}$ vs. 1/T were found to be curved with increased slope but $ln{\gamma}{\infty}$ values at constant temperature were linearly increased as increasing the number of carbon atoms of solute molecule.

• Polymer(Korea)
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• v.30 no.5
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• pp.380-384
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• 2006

Polyhedral oligomeric silsesquioxanes (POSS) were used as starting materials for the preparation of hybrid materials with polystyrene (PS). Optically transparent hybrids were obtained in a wide range of weight ratios when phenyl groups were introduced to each corner of the silsesquioxane. In contrast, as cyclohexyl groups were introduced, the obtained hybrid materials with PS resulted in turbid films. The aromatic (${\pi}-{\pi}$) interaction was confirmed to be a quite effective tool for the synthesis of organic-Inorganic polymer hybrids with POSS. The obtained homogeneous and transparent hybrid films could be dissolved in solvents and East again without any separation. The homogeneity of polymer hybrids with POSS was supported by the result of scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), which demonstrated a nanometer-level integration of PS and POSS.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.291-292
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• 2003

Amphiphilic block copolymer는 self-assembly특성을 가지고 있기 때문에 선택된 용매 속에서 nanoscale-domain 즉 micelle을 형성할 수 있다. 이러한 특성은 기타 불용성 물질을 가용화하고 colloidal particle을 안정화시키거나 micro-emulsion을 형성할 수 있어 pharmaceutics, drug delivery system등 영역, 그리고 emulsion stabilizer, thickener, dispersion agent등으로 사용될 수 있다. (중략)

• Prospectives of Industrial Chemistry
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• v.22 no.3
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• pp.6-10
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• 2019

용액공정을 이용하여 우수한 특성을 가지는 OLED를 제작하기 위해서는 다층 박막을 형성하여야 하며, 일반적인 용액공정으로는 다층 구조를 형성하는 데에 어려움이 있어 다양한 공정 및 재료에 대한 연구와 개발이 이루어지고 있다. 박막을 전사하는 방법은 상부막에 사용되는 용매의 침투에 의한 하부막 손상을 최소화할 수 있다는 장점을 가지고 있지만, 사용할 수 있는 전사 공정은 극히 제한적이다. 본 기고에서는 전사 공정으로서 산업에 이용되고 있는 hydrographic printing (수전사) 공정을 OLED 제조에 적용하고 그 가능성에 대하여 알아보고자 한다.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.1015-1019
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• 1996

Several alkyl chlorides were brominated using LiBr and $CaBr_2$ adsorbed on alumina in the absence of solvent. The yields of alkyl bromides were fairly high. Such a high reactivity by these bromide salts might be due to the interaction of minute amount of water and the salt on alumina. Differential scanning calorimetry (DSC) thermogram was provided and discussed.

• Proceedings of the EASDL Conference
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• 2004.10a
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• pp.73-92
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• 2004

참기름은 높은 온도로 볶아 짜는 공정을 통해 제조되는데 이때 참깨의 성분 중 당과 단백질에 의한 Maillard 반응에 의해 향기성분인 pyrazine 화합물과 갈샐물질이 생성된다. 참깨의 볶는 방법, 온도 및 시간은 참기름의 맛과 향기에 중요한 인자가 될 수 있고 또한 참기름에 함유되어 있는 갈색물질과 향기성분인 pyrazine류가 생리활성을 나타낼 수 있는 가능성이 제기되어 본 연구에서는 참기름으로 부터 갈색화 관련 물질을 용매별로 분류하여 tyrosinase 저해 효과와 항상화 효과를 측정였고 pyrazine 유도체들의 혈소판 응집에 미치는 효과를 측정하였다. 갈색도가 높은 butanol, methanol 에서 농도 의존적으로 높은 tyrosinase 저해효과를 보였다. 또한 각종 radical 소거능을 측정한 결과 butanol 에서 높은 소거능을 보였다. 향기 성분에 다량 함유되어 있는 Pyrazine 유도체가 collagen 에 의해 유도된 혈소판 응집억제능을 측정한 결과 -methyl의 결합수가 많을수록 (2,3,5-trimethylpyrazine>2,5-dimethylpyrazine>pyrazine) 농도 의존적으로 높은 응집 억제효과를 나타내었다. 이상의 결과, 참기름 가공 공정에서 생성되는 갈색화관련 물질과 향기 성분인 pyrazine 유도체는 생리활성을 나타내는 물질임이 확인되어 기능성 식품에 다양하게 활용되기를 기대한다.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.299-304
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• 2005

There have been many efforts to use anionic hydrogels as oral protein delivery carriers due to their pH-responsive swelling behavior. The dynamic swelling behavior of poly(methacrylic acid-co-methacryloxyethyl glucoside) [P(MAA-co-MEG)] hydrogels was investigated to determine the mechanism of water transport through these anionic hydrogels. The exponential relation $M_t/M_{\infty}=kt^n$ was used to calculate the exponent, n, describing the Fickian or non-Fickian behavior of swelling polymer networks. The mechanism of water transport through these gels was significantly affected by the pH of the swelling medium. The mechanism of water transport became more relaxation-controlled in the swelling medium of pH 7.0 that was higher than the $pK_a$ of the gels. Experimental results of time-dependent swelling behavior of the gels were analyzed with several mathematical models. Using ATR-FTIR spectroscopy, the effect of ionization of the carboxylic acid groups in the polymer networks on the water transport mechanism was investigated.

• Resources Recycling
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• v.25 no.2
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• pp.33-41
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• 2016

A scale up tests (380 kg/day) using a continuous solvent extraction and electro-winning system was carried out to separate and recover cobalt from a solution containing 1.91 g/L Co and 14.65 g/L Ni. The solution was obtained during a process including solvent extraction and precipitation stages for removal of Cu and Fe from a synthetic sulfuric acid solution of manganese nodule matte. The optimal condition for solvent extraction was : solvent concentration of 0.22M Na-Cyanex 272 (45% saponified with NaOH) and O:A phase ratios of 1:1.5, 10:1 and 1.5:1 used in extraction, scrubbing and stripping stages, respectively. The extraction and stripping efficiencies were found to be 99.8% and 99.88%, respectively. The stripped solution contained 40.27 g/L Co with 4 ppm Ni. Cobalt metal of 99.963% purity was yielded with current efficiency of 67% and current density of $0.563A/dm^2$ during the electro-winning process.

• Journal of Life Science
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• v.25 no.3
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• pp.345-348
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• 2015

An organic solvent stable lipase from solvent-tolerant Pseudomonas sp. BCNU 171 had an optimal pH of 8 and an optimal temperature of 37℃. This crude extracellular lipase from BCNU 171 exhibited increased stability in the presence of various types of solvents at high concentrations (25%, v/v). The lipase stability was found to be highest in the presence of xylene (137%), followed by toluene (131%), octane (130%), and butanol (104%). Overall, BCNU 171 lipase tended to be more stable than immobilized commercial lipase (Novozyme435) in the presence of organic solvents. Furthermore, BCNU 171 lipase maintained about 90% of its enzyme original activity in the presence of NH₄⁺, Na⁺, Ba²⁺, Hg²⁺, Ni²⁺, Cu²⁺, and Ca²⁺ion and significantly increased its enzyme activity in the presence of various emulsifying agents. Thus, the organic solvent stable lipase from Pseudomonas sp. BCNU 171 could be usable as a potential whole cell biocatalyst and for synthetic applications of enzymes for industrial chemical processes in organic solvents without using immobilization.