• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.318-322
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• 1999

Perdeuterated hexaflouroacetylacetonato-neodymium [$Nd(HFA-D)_3$] complexes were synthesized by the keto-enol tautomerism reaction of $Nd(HFA-D)_3$ in methanol-d$_4$ in order to reduce the radiationless transition to the ligands. The emission properties of $Nd(HFA-D)_3$ complex were measured in the following anhydrous deuterated organic solvents; $Methanol-d_4$, $Aceton-d_6$, $THE-d_8$ and $DMSO-d_6$, and these properties depended on the coordination ability of solvent molecules. The intensity and lifetime of the emission in dimethysulfoxide (DMSO-$d_6$) were superior to those in other in other deuterated solvents. It was suggested that the anhydrous $DMSO-d_6$might be the most appropriate solvent for the liquid laser material of $Nd(HFA-D)_3$ complex.

• Korean Journal of Medicinal Crop Science
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• v.11 no.1
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• pp.19-23
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• 2003

The optimum extraction condition of pungent component from Zanthoxylum piperitum D.C pericarps by using supercritical fluid extraction(SFE) was investigated. The optimum condition of SFE was $300kg/cm^2$ of pressure, $60\;^{\circ}C$ of extraction temperature, 80% of $CO_2$ fluid, 20% of modifier(methanol) volume and 20 min of extraction time. The extraction efficiency between the classical solvent extraction method and SFE was studied. About 40% of extraction efficiency was improved when SFE was applied.

• Resources Recycling
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• v.29 no.6
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• pp.57-64
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• 2020

In this study, removal of OCA and organic impurities for recycling LCD touch panel glass was conducted by mechanical and chemical dissolution methode. Cut mill and oscillation mill were used for mechanical crushing of touch panel, and water, ethanol, dichloromethane were used to remove OCA and organic impurities. As a result of TGA, when applied only dicloromethane in the process, the efficiency of organic removal was to be best. In addition, removal effect of organic impurities increased as the cleaning temperature increased. As a result of zeta potential analysis to confirm the dispersion degree of touch panel glass in the solvent, the absolute value of the zeta potenial of water with the lowest cleaning effect was lower than other solvents, and it was confirmed that efficiency of organic removal is affected not only by the chemical dissolution properties but also the physical dispersion properties in the solvent.

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.488-493
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• 2003

Nickel fine powders were prepared from aqueous nickel chloride solution containing organic solvents and the effect of the addition of the organic solvent on the formation of nickel powders were investigated. All products were spherical particles in the range of 0.1∼1.0 $\mu\textrm{m}$ and the agglomeration of particles did not appear. In case of containing 40 vol% of 1-propanol, the particle size reduction and homogeneity of the powders were remarkable. The average particle size and the specific surface area of the powders produced with 40 vol% of 1-propanol were 0.3 $\mu\textrm{m}$ and 16.4 m$^2$/g respectively. The reduction reaction time by hydrazine decreased with increasing of the content of 1-propanol, and was 5 min for 40 vol% of 1-propanol. The oxidation of synthesized nickel powders occurred at 320$^{\circ}C$ and weight loss at 300$^{\circ}C$ was due to dehydration of Ni(OH)$_2$.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.779-785
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• 1994

The interaction between the cationic dye, thionin(Th) and the anionic surfactant, sodium dodecyl sulfate (SDS) has been investigated by absorption spectra. As the temperature of surfactant solution was increased in premicellar range(S/D=10, 80, and 160) which was much lower than the critical micelle concentration(CMC), the increment or decrement of the molar extinction coeffecient ratio appeared. It was found that the most stable temperature range of the oligomer aggregate in Th-SDS system at S/D=160 was below $60^{\circ}C$. With increasing the concentration of inorganic salt and organic solvents in Th-SDS system, ${\alpha}$-band was increased, but ${\gamma}$=band or J-band was decreased. The orders of ${\alpha}$-band increasing power were $Cl^-$>$ClO{_4}{^-}$>$SO{_4}{^{2-}}$>$NO{_3}{^-}$ and 2-propanol>ethanol>methanol>ethylene glycol.

• Journal of Life Science
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• v.26 no.5
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• pp.603-607
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• 2016

A crude extracellular lipase from solvent-tolerant bacterium Pseudomonas sp. BCNU 106 was highly stable in the broad pH range of 4-10 and at temperature of 37℃. Crude lipase of BCNU 106 exhibited enhanced stability in 25% organic solvents such as xylene (121.85%), hexane (120.35%), octane (120.41 %), toluene (118.14%), chloroform (103.66%) and dodecane (102.94%) and showed excellent stability comparable with the commercial immobilized enzyme. In addition, the stability of BCNU 106 lipase retained above 110% of its enzyme activity in the presence of Cu²⁺, Hg²⁺, Zn²⁺ and Mn²⁺, whereas Fe²⁺ strongly inhibited its stability. The detergents including tween 80, triton X-100 and SDS were positive signals for lipase stability. Because of its stability in multiple organic solvents, cations and surfactants, the Pseudomonas sp. BCNU 106 lipase could be considered as a potential biocatalyst in the industrial chemical processes without using immobilization.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.448-452
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• 2016

This study is for the effective pretreatment and saccharification of lignocellulosic biomass for a transport fuel receiving attention. The waste water during the pretreatment of biomass is major factor for determining the price of biofuel. Therefore, we conducted high concentration of organosolv pretreatment for decline waste water and reusing the solvent. We confirmed effect of organosolv pretreatment by components analysis and enzymatic hydrolysis of pretreated biomass. The corn stover was used for and 99.5 wt% of ethanol as a organosolv pretreatment. The pretreatment condition was varied 130 to $190^{\circ}C$ during the designated reaction times and the effect of pretreatment was investigated by enzymatic hydrolysis. The highest glucose conversion was more than 68% the pretreatment condition of $190^{\circ}C$ for 70 min or more. The solid remaining was more than 70% and almost of cellulose and hemicellulose were survived.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.114-114
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• 2018

탄소 재료는 뛰어난 물성에서 다양한 재료로의 응용이 기대되고 있다. 특히, 이종 원소 함유 카본 재료는 전기적 특성과 촉매성의 발현 등 새로운 기능을 카본 재료에 부여할 수 있어서 연료 전지, 에너지 저장, 태양 전지 등에의 응용이 기대되고 있다. 최근, 용액 중의 저온 플라즈마인 솔루션 플라즈마(solution plasma process)를 이용하여 벤젠 용액 등에서 탄소 재료 합성에 성공하였다. 그러나 기존의 연구에서는 솔루션 플라즈마 프로세스를 이용하여 합성한 이종원소 카본은 전도성이 낮아 이종원소의 함유량을 낮추는 고온의 열처리가 필요했다. 따라서 본 연구에서는 우수한 물리적 전기적 특성을 갖는 그래핀(graphene)과 같은 이종 원소 카본 나노시트(heteroatom carbon nanosheets)의 합성 및 메커니즘(mechanism)에 대해 검토하였다. 다양한 이종원소를 포함한 유기용매 안에 바이폴라 펄스 전원에 의한 전압을 두 텅스텐 전극 간에 인가하고, 솔루션 플라즈마를 생성하여 이종원소 카본 재료를 합성했다. 플라즈마 생성은 텅스텐 봉을 전극으로 사용하고 전압을 2.0 kV, 펄스 주파수를 200 kHz, 펄스 폭을 $1.0{\mu}s$, 전극 간 거리를 1.5 mm에서 일정하게 유지하며 200 mL 유기용매 중에서 방전시키는 것으로 재료를 합성했다. 플라즈마 방전 후, 필터을 이용하여 흡인 여과한 뒤 $200^{\circ}C$에서 1 시간 동안 건조 시켰다. 건조 후의 이종원소 카본의 물리적 특성을 원소 분석, X선 회절 법(XRD), 저항률 측정, 투과형 전자 현미경(TEM) 및 라만 분광법, 전자 현미경(SEM), X-선광전자분광기(XPS)등을 이용하여 카본의 형상 및 특성을 분석하였다. 그 결과 다양한 이종원소를 포함한 유기용매 중 2-pyrrolidone을 사용했을 때, 이종 원소 카본 나노시트를 합성하는데 성공하였다. 또한, 이 연구방법을 통해서 솔루션 플라즈마 프로세스를 통한 카본 나노시트 합성의 메커니즘을 규명하였다.

• Journal of Life Science
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• v.23 no.10
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• pp.1246-1251
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• 2013

An organic solvent-tolerant lipase of Pseudomonas sp. BCNU 154 that was isolated from wastewater in the industrial complex region had optimal activity at $37^{\circ}C$ and pH 8. This crude extracellular lipase from BCNU 154 exhibited maximum stability in toluene, retaining about 6.01 U/ml (117.53%) activity for 2 h. $Ca^{2+}$, $Mg^{2+}$, $NH_4{^+}$, and $Na^+$ ions and triton X-100 activated the enzymes, whereas $Ba^{2+}$, $Hg^{2+}$, and $Zn^{2+}$ ions inhibited their activity. Pseudomonas sp. BCNU 154 lipase revealed stable activity comparable to that of the commercial immobilized Novozym 435. Thus, this organic solvent-tolerant lipase could have potential as a whole cell biocatalyst in industrial chemical processes without the use of immobilization.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.624-628
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• 1998

The aromatic organic solvents(BTX) were decomposed in the fixed bed reactor packed with a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst, then, supercritical carbon dioxide(SC-$CO_2$) was used as the reaction media. And the conversion was dependent on the inlet concentration of BTX and the molar density of SC-$CO_2$. The conversion of BTX was decreased with increasing of inlet concentration, and was increased with temperature and pressure. The maximum conversion of benzene was 98.5% at $300^{\circ}C$ and 204.1 atm, and that of toluene and xylene were 82.0 and 76.5%, respectively, at $350^{\circ}C$ and 204.1 atm. The intermediate products of partial oxidation were identified as benzaldehyde, phenol, benzenemethanol, and so on. The BTX can be effectively converted into harmless $CO_2$ and $H_2O$ at appropriate operating condition. Thus, the nontoxic recovery process was suggested as the removal method of BTX.