• 한국산학기술학회논문지
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• 제16권8호
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• pp.5721-5727
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• 2015

페인트는 외부로부터 본체가 손상되는 것을 막아주며, 오랫동안 색깔과 마무리 상태를 유지해 준다. 유기용제와 물이 페인트의 용제로 사용되고 있으며, 유기용제는 VOCs의 인위적인 공급원으로 알려져 있다. 이러한 이유로 자동차 내장부품에서 유기용재 페인트의 사용은 줄어들고 있으며, 외장 부품에서는 계속 사용하고 있다. 수성페인트의 접착력은 유성페인트에 비하여 작아, 페인트가 기제로부터 박리되고 있어, 품질문제를 일으킨다. 본 연구에서는 수성페인트와 실린 혼합물의 접착 특성에 대하여 연구하였다. 수성페인트의 접착력을 향상시키기 위하여 접착제와 혼합이 필요하다. 접착력은 UTM을 이용하여 ASTM D1002 방법으로 측정하였고, 박리현상은 ASTM D1002를 사용하여 측정하였다. 수성페인트와 실란접착제의 최적 혼합조건은 $25^{\circ}C$, 500rpm, 20분 이었으며. 실란접착제 농도는 5wt% 이었다

• 생명과학회지
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• 제5권4호
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• pp.155-161
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• 1995

The effects of substrate concentration, enzyme concentration, reaction temperature, and water content were investigated in intramolecular esterification. This study used cyclohexane as organic solvent, power lipase as enzyme, and benzyl alcohol and octanoic acid as substrate. The initial reaction rate was found to be proportional to enzyme concentration; followed Michaelis-Menten equation for octanoic acid; and was inhibited by benzyl alcohol . The observed initial reaction rate first increased, then decreased with increasing reaction temperature, giving rise to the maximum rate at 20$\circ$. The drop in the reaction rate at higher temperature was to partition equilibrium change of substrate between organic solvent and hydration layer of enzyme molecule in addition to the deactivation by enzyme denaturation. Water layer surrounding enzyme molecule seemed to activate in organic solvent and the realistic reaction was done in the water layer. In the enzymatic reaction in organic solvent, the initial reaction rate was influenced by partition quilibrium of substrate, so the optimum condition of substrate concentration, enzyme concentration, reaction temperature, and water content would give a good design tool.

• Rapid Communication in Photoscience
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• 제4권3호
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• pp.67-69
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• 2015

FTIR spectroscopy has been employed to investigate the variation of anion-water hydrogen bonding in 1-butyl 3-methyl imidazolium tetrafluoroborate ([Bmim][$BF_4$]) ionic liquid caused by addition of organic co-solvents with various polarities. The variation was estimated by probing band shape and intensity of the OH stretching vibration of trace water present in ionic liquid at $3400-3800cm^{-1}$. The presence of polar aprotic co-solvent in ionic liquid dramatically reduces the absorptivity of the OH stretch band, indicating that the co-solvent changes the nature of anion-water hydrogen bond drastically, which might be responsible for the reduction of the viscosity of ionic liquid in the presence of the co-solvent.

• 한국염색가공학회지
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• 제13권2호
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• pp.42-42
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• 2001

Following the prior studs regarding that 1.0g of cotton fabric cound be dyed uniformly with a reactive dye in the solvent mixture of 2㎖ of water and 23㎖ of dichloromethane, silk fabric was dyed with C. I. Reactive Blue 203 in the water/dichloromethane two-phase immiscible solvent media. In order to minimize dye loss due to its hydrolysis, the reactive dyeing was carried out in dichloromethane containing a small amount of water. With only 3㎖ of water in 22㎖ of dichloromethane, 1.0g of silk fabric could be dyed perfectly. The uptake ratio was increased greatly, compared with that of normal reactive dyeing in a water medium. It would seem that the one of hydrophobic solvents, dichloromethane, can assist the even dyeing as it disperses a small amount of dye-dissolved water phase and conveys this water phase to the fabric entirely and uniformly.

• 대한화학회지
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• 제27권3호
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• pp.167-177
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• 1983

물-메탄올, 물-에탄올, 물-아세톤 및 물-아세토니트릴의 2-성분 혼합용매 속에서 2-염화안트라센 술포닐의 가용매 분해반응을 전기전도도법을 써서 속도론적으로 고찰하였다. 물의 몰분률이 같은 혼합용매속에서는 쌍극자성 반양성자 용매에서 보다 양성자성 용매에서 속도가 컸으며, 물-메탄올 혼합용매에서는 실험 농도의 전체 범위에 걸쳐 물-에탄올에서 보다 항상 속도가 컸으나 아세톤과 아세토니트링의 경우에는 몰분율 0.9에서 속도의 크기가 뒤바뀌었다. 용매의 이온화 능력에 대한 반응의 감도를 나타내는 m와 전이상태에서의 물의 관여차수 n값은 모두 쌍극자성 반양성자용매에서 컸다. 이들 값과, 속도상수에서 결정한 활성화 파라미터로부터 2-염화안트라센 술포닐의 가용매분해반응은$ S_N2$ 메카니즘으로 진행된다는 것을 알았다.

• The Korean Journal of Ceramics
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• 제7권2호
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• pp.55-57
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• 2001

For the fast dry of the aqueous tape, the process which water was replaced by organic solvent was proposed. Socalled, it was the solvent washing dry. Three organic solvents (methanol, ethanol and acetone) were selected for the washing solvent. The weight loss of the washed tapes was measured to evaluate the dry rate of the tapes and dried tapes were examined the generation of the cracks with the variations of the organic solvent and the washing time. Methanol, ethanol and acetone were available organic solvents for this method. The tapes washed in methanol, ethanol and acetone were dried rapidly for twenty minutes. After thirty minutes, the weight losses were not found any more. The solvent of the lower surface tension can decreases the crack of dried tape. If solvent substitutes water completely, though it was fast dried, crack can be eliminated.

• Korean Chemical Engineering Research
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• 제44권1호
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• pp.92-96
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• 2006

유기용매에서 효소를 이용하면 다양한 선택적 반응을 쉽게 수행할 수 있어 산업적 적용 가능성이 매우 높지만, 효소의 안정성 저하는 아직까지 큰 문제 중의 하나로 남아있다. 유기용매에서 효소 반응시 효소의 실활 원인과 효소의 안정화 방법 연구를 위하여 단백질의 folding에 관여하는 molecular chaperone의 일종인 heat-shock protein Hsp90을 이용하여, 대표적인 유기용매 반응시스템에서의 과산화효소 HRP 안정성 향상 연구를 수행하였다. 그 결과 Hsp90은 30％ DMSO, 30％ 및 50％ dioxane 완충용액에서 HRP의 실활 방지 효과를 보였고, 실활된 효소의 재생에도 탁월한 효과를 보였다. 그리고 형광분석과 CD(circular dichroism)에 의한 구조분석을 수행하여 Hsp90이 유기용매에 의해 unfolding되어 있는 효소를 다시 refolding하는 데 기여함을 알았다.

• 한국염색가공학회지
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• 제13권2호
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• pp.128-134
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• 2001

Following the prior studs regarding that 1.0g of cotton fabric round be dyed uniformly with a reactive dye in the solvent mixture of $2m\ell$ of water and $23m\ell$ of dichloromethane, silk fabric was dyed with C. I. Reactive Blue 203 in the water/dichloromethane two-phase immiscible solvent media. In order to minimize dye loss due to its hydrolysis, the reactive dyeing was carried out in dichloromethane containing a small amount of water. With only $3m\ell$ of water in $22m\ell$ of dichloromethane, 1.0g of silk fabric could be dyed perfectly. The uptake ratio was increased greatly, compared wish that of normal reactive dyeing in a water medium. It would seem that the one of hydrophobic solvents, dichloromethane, can assist the Even dyeing as it disperses a small amount of dye-dissolved phase and conveys this water phase to the fabric entirely and uniformly.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.283-292
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• 2023

Currently, spray coating has attracted interest in the mass production of anode catalyst layers for proton exchange membrane water electrolysis (PEMWE). The solvent in the spray ink is a critical factor for the catalyst dispersion in ink, the microstructure of the catalyst layer, and the PEMWE performance. Herein, various pure organic solvents were examined as a substitute for conventional isopropanol-deionized water (IPA-DIW) mixture for ink solvent. Among the polar solvents that exhibited better IrO₂ dispersion over nonpolar solvents, 2-butanol (2-BuOH) was selected as a suitable candidate. The PEMWE single cells were fabricated using 2-BuOH at various ionomer contents, spray nozzle types, and drying temperatures, and their performance was compared to the cells fabricated using a conventional IPA-DIW mixture. The PEMWE single cells with 2-BuOH solvent showed good performances comparable to the conventional IPA-DIW mixture case and highly durable performances under accelerated degradation tests.

• Environmental Engineering Research
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• 제11권5호
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• pp.241-249
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• 2006

A mathematical model is described for the prediction of convective upward transport of an organic solvent driven by evaporation at the surface, which is known as the major transport mechanism in the in-situ photolysis of a soil contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD). A finite-element model was proposed to incorporate the effects of multiphase flow on the distribution of each fluid, gravity as a driving force, and the use of hysteretic models for more accurate description of k-S-p relations. Extensive numerical calculations were performed to study fluid flow through three types of soils under different water table conditions. Predictions of relative permeability-saturation-pressure (k-S-p) relations and fluids distribution for an illustrative soil indicate that hysteresis effects may be quite substantial. This result emphasizes the need to use hysteretic models in performing flow simulations including reversals of flow paths. Results of additional calculations accounting for hysteresis on the one-dimensional unsaturated soil columns show that gravity affects significantly on the flow of each fluid during gravity drainage, solvent injection, and evaporation, especially for highly permeable soils. The rate and duration of solvent injection also have a profound influence on the fluid saturation profile and the amount of evaporated solvent. Key factors influencing water drainage and solvent evaporation in soils also include hydraulic conductivity and water table configuration.