• Transactions on Electrical and Electronic Materials
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• 제13권2호
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• pp.89-92
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• 2012

The effect of organic impurities on the electrical properties of a neat epoxy resin was studied. 0.05, 0.5 and 1.0 phr of iso-propyl alcohol (IPA) and methylene chloride (MC) mixture (50/50 wt%) were used as impurities. The current density, volume resistance and impedance characteristics of the epoxy/IPA/MC systems were measured with a high voltage source meter and broadband dielectric spectroscopy. Glass transition temperature (Tg) was measured by a differential scanning calorimetry (DSC) and it was found that Tg decreased slightly with increasing IPA/MC content. It was also found that Tg values of the epoxy systems with various IPA/MC contents were closely related to the current density, volume resistance and impedance characteristics.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.392.2-392.2
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• 2014

Poly (vinylidene fluoride) thin films were deposited by a spray-coating technology. Two organic solvents with different boiling point were used to prepare the mixture solution for spray coating process: N-Methylpyrrolodone ($B.P.=202^{\circ}C$); Tetrahydrofuran ($B.P.=66^{\circ}C$). Post-deposition annealing temperature was varied for the spray-coated Poly(vinylidene fluoride) thin films. Structural characteristics of the thin films were comparatively investigated by FT-IR and XRD in relation with the organic solvent and post-deposition annealing temperature.

• 대한화학회지
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• 제11권4호
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• pp.121-125
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• 1967

各種 아민과 할로겐化合物間의 Charge Transfer Complex 形成與否를 檢討하여 보았다. Pyridine Tridthylamine, Piperidine Ethanolamine Triethanolamine, Aniline, Diethylamine 等의 아민類와 四鹽化炭素 또는 클로로폼의 混合溶液을 n-Hexane 溶媒存在下에서 紫外線吸收 스펙트라를 檢査한 結果 장파장쪽의 Shift가 있었으며 特히 Diethylamine과 Triethylamine은 클로로폼 또는 四鹽化炭素와 1:1 Charge Transfer Complex를 形成하였고, Piperidine은 接觸的 Complex를 形成하는 것이 確認되었다. Complex의 形成경향과 아민의 Nucleophilicity와의 關係를 論議하였다.

• KSBB Journal
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• 제14권6호
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• pp.696-701
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• 1999

본 연구에서는 lipase를 이용해서 ricinoleic acid를 대량생산하기 위해 피마자유의 완전가수분해 조건을 찾고자 하였다. 널리 알려진 lipase CR, lipase CC, lipase PP를 대상으로 피마자유의 가수분해의 가능성을 시험하고, 유기용매를 사용함으로써 가수분해도를 향상시킬 수 있음을 확인하였다. 일반적으로 lipase의 활성을 감소시키는 극성용매의 경우 피마자유의 가수분해에 있어서도 효소의 활성을 감소시켰고, 물과 섞이지 않는 hydrophobic solvent가 피마자유의 가수분해도를 크게 증가시키는 것을 확인하였다. 본 연구에서는 isopropyl ether의 효과가 가장 크며, 조건에 따라 가수분해도를 두 배 이상 증가시킨다는 것을 확인하였다. 그리고 유기용매를 사용함으로써 pH의 영향을 바꾸거나 감소시킬 수 있다는 사실도 확인하였다. 용매와 물의 부피비에 의해서 가수분해가 영향을 받는다는 사실과 특히 유기용매보다는 물의 양에 절대적으로 영향받는다는 사실을 발견하였다. 하지만, 물과 유기용매의 부피비와 함께 lipase와 피마자유의 무게비도 매우 중요하다는 것을 확인하였다. 30$^{\circ}C$에서 isopropyl ether를 사용할 경우 무게 비로 2 wt%일 때는 약 82%, 4 wt% 이상의 lipase CC나 lipase CR을 사용하면 피마자유가 완전히 가수분해되는 사실을 발견하였다.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2109-2113
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• 2014

Solvent extraction of Fe(III) from chloride solution by using a mixture of D2EHPA (Di-(2-ethylhexyl)-phosphoric acid) and TBP (Tri-butyl phosphate) and the reductive stripping of Fe(III) from the loaded organic were investigated. Quantitative extraction of Fe(III) from the solution (Fe concentration = 90 g/L) was accomplished in two cross-current extraction stages by using the mixture of D2EHPA and TBP. In order to facilitate the stripping efficiency, a reductive stripping method was employed by using $H_2SO_3$ or $Na_2SO_3$ as a reducing agent. The addition of $H_2SO_4$ into reducing agents led to improvement in the stripping efficiency while high concentration acid would suppress it. Both of the mixtures of $H_2SO_4+H_2SO_3$ and $H_2SO_4+Na_2SO_3$ showed good efficiency for the stripping of Fe(III), while the latter was recommended as the stripping solution based on the economics and experimental condition.

• 약학회지
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• 제46권5호
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• pp.352-357
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• 2002

The three crude drugs of the Kalopanax pictus (Araliaceae) roots (K), Pueraria thunbergiana (Leguminosae) flowers (P), and the Rhus verniciflua (Anacardiaceae) heartwood(R) used for anti-thirst drugs in Oriental herb medicine were extracted with MeOH, respectively, and the successive fractionation of the extract gave EtOAc extract. Certain amount ratios of the three extracts were also prepared to compare the antimutagenicity in Ames test. In N-methyl-N(-nitro-N-nitrosoguanidine (MNNG; 0.4 (g/plate)-induced test, the activities of complex mixture were observed between the highest antimutagenic activity of K extract and the lowest P extract. In aflatoxin (AFB$_1$)-induced test, the EtOAc complex (K : P : R=l : 1 : 3) labeled E-113 decreased the revertants of Salmonella typhimurium TA100 by 95％, which activity were highest among other extracts or complexes mixture used. Fractionation of organic solvent mostly increased the antimutagenicity. These trends were also observed in the antimutagenicity test of the mixture of each active component of kalopanaxsaponin A, tectorigenin and sulfuretin. These results supported that many kinds of anti-thirst herb medicine in the prescription could effectively prevent cancer disease.

• 약학회지
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• 제44권2호
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• pp.135-140
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• 2000

Determination of Aconitum alkaloids in processed Buza (Cho-0, Salted Buza, Moist-heating Buza, Limed Buza), which had been prepared from the raw tubers of Aconitum chiisanenseb(Ranunculaceae), was established using visible spectrophotometry and high-performance liquid chromatography (HPLC) method especially for Aconitine analysis. Aconitum alkloids were reacted with tetra- thiocy-anatocobalt[II] complex ion to form a stable ion pair. The reaction product was insoluble in water but freely soluble in several organic solvents. 1.2-Dichloroethane was the best extracting solvent among the examined solvents. Spectrophotometry of Aconitum alkaloids at nax. 625 was carried out. The HPLC method for aconitine was carried out using Radial PAK-CN column with gradient solvent system by solvent mixture of acetonitrile and phosphate buffer (pH 3.0) at 4$0^{\circ}C$ and 254 nm. Linear relationship was found between absorbance response and concentration of aconitine in range of 0.45 mM~0.9 mM ($r^2$=0.9949) by spectrophotometry and 0.3 mM~1.2mM($r^2$=0.9983) by HPLC method. These methods have been found to be suitable and reproducible for routine analysis of Aconitum alkaloids and its pharmaceutical preparations.

• 한국대기환경학회지
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• 제12권4호
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• pp.479-485
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• 1996

Volatile organic compounds are air pollutants exhausting from industrial process, evaporation of solvent, and so on. Most of VOCs are the combustible gas of low calorific value as it is diluted by air. The systems burning such a hazardous gas need to increase enthalpy in order to increase flame stability. In this study an incinerator with reciprocating flow in the honeycomb ceramic has been used for the experiment of VOCs control. By the reciprocating flow system, the enthalpy of combustion gas is effectively regenerated into the enthalpy increases of the combustible gas through the honeycomb ceramic, which provides a heat storage. The position of the reaction zone is strongly dependent on the parameters of mixture velocity and time frequency. Flame front is changed to the point where burning velocity is coincided with burning velocity in the honeycomb ceramic. In this system it is important that flame front should be located symmetrically at the center of honeycomb ceramic for the purpose of increasing the reaction rate at one point. Peak temperature becomes higher with decreasing time frequency, at which the flow direction is regularly reversed.

• 대한화학회지
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• 제9권1호
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• pp.61-65
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• 1965

有機클로로酸, 또는 에스타와 各種金屬(亞鉛, 硅素, 마그네슘, 錫)과의 여러 溶媒存在下(아세트나이트라일, 디옥센 및 토루엔)의 反應에서 얻은 反應生成物, 또는 反應系中의 金屬分布狀態를 (n,${\gamma}$)反應으로 製造한 各種放射性 金屬트레이서를 使用하여 決定하였다. 有機클로로 金屬 콤푸렉스의 溶解度는 親水性溶媒에서는 顯著하게 增加하였으며, 無極性溶媒에는 減少하였다. 이 事實은 回收된 金屬, 또는 回收된 金屬混合物의 水洗液中의 金屬分布狀態의 增加로서 確認되었다. 카보닐化合物 存在下에서 反應시켰 때에도 같은 事實을 나타내었다. 親水性溶媒中의 金屬콤푸렉스의 溶解度는 亞鉛, 硅素, 錫 및 마그네슘이 順序로 減少되었으며 無極性溶媒下에서는 硅素, 錫, 마그네슘 및 亞鉛의 順으로 減少되었다. 有機할로겐化合物과 金屬과의 反應生成物로 普通 豫期되는 有機金屬化合物은 全反應을 通하여 거의 없었다. 反應結果를 論議하였으며, 本反應過程에서 觀察한 溶媒의 影響에 關하여 論及하였다.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.73-78
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• 1992

Tryptophanase를 이용하여 트립토판 합성시 인돌의 효소활성 저해를 억제하기 위하여 유가식 조업, 유기용매 이상계의 사용, 그리고 cyclodextrin의 첨가등에 대하여 연구하였다. 효소 농도가 0.5mg/ml일때 인돌 농도 0.4mM 부근에서 트립토판 생성이 가장 빨랐으며 그 이상에서는 효소활성이 심한 저해를 받았다. 초기 인돌 농도가 20mM일 때는 27시간 반응후 인돌의 전환율이 20인데 비하여 반응기내 인돌 농도를 5mM 이하로 유가식 조업을 하였을 때 전환율이 80%로 향상되었다.