• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.1-2
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• 2003

While aromatic polyimides and polyamides have found widespread use as high performance polymers, the present work addressed the need for organosoluble materials through the use of a hyperbranching scheme. The $AB_2$ monomers were prepared. The $AB_2$ monomers were then polymerized via aromatic fluoride-displacement and Yamazaki reactions to afford the corresponding hydroxyl-terminated hyperbranched polyimides (HT-PAEKI) and amine-terminated hyperbranched polyamides, respectively. HT-FAEKI was then functionalized with allyl and propargyl bromides as well as epichlorohydrin to afford allyl-terminated AT-PAEKI, propargyl-terminated PT-PAEKI, and epoxy (glycidyl)-terminated ET-PAEKI, in that order. All hyperbranched poly(ether-ketone-imide)s were soluble in common organic solvents. AT-PAEKI was blended with a bisphenol-A-based bismaleimide (BFA-BMI) in various weight ratios. Thermal, rheological, and mechanical properties of these blend systems were evaluated. Two characteristic hyperbranched polyamides, which the one has para-electron donating groups to the surface amine groups and the other has para-electron withdrawing groups to the surface amine groups, were selected to compare BMI curing behaviors. The electron rich polymer displayed ordinary Michael addition type exothermic reaction, while electron deficient polymer did display unusual curing behaviors. Based on analytical data, the later system provided the strong evidences to support room temperature curing of BMI by reactive intermediates instead of reactive primary amine groups on the macromolecule surface.

• 한국수산과학회지
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• 제40권3호
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• pp.113-116
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• 2007

We investigated the characteristics of various Tofu coagulants extracted from sea tangle using treated deep ocean water (DOW) as the solvents. The coagulants were typical solutions extracted from sea tangle using raw DOW and strongly electrolyzed acidic (SAC) or alkaline (SAK) water. The total dissolved solids (TDS), NaCl and electric conductivity were increased in the coagulant solution extracted by SAC than the others. In the coagulant solutions extracted by acidic electrolyzed solvent, aspartic acid content (13.5 mg/100 g) was higher than others (11.2 and 12.1 mg/100 g). The Tofu obtained using coagulants extracted with treated DOW had the water contents ranging from 79.55% to 80.04%. The contents of crude protein (12.1 g/100 g) and Na, Ca, K and Mg were relatively higher than general Tofu commercially available. Therefore, coagulant solutions extracted from sea tangle using treated DOW can be used to develop natural high-grade tofu for practical use.

• 한국식품과학회지
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• 제24권6호
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• pp.552-557
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• 1992

영지추출액의 세균, 효모, 곰팡이에 대한 항균활성을 cup cylinder method와 MIC로 검색한 결과 세균에 대해서만 활성을 나타내었으며 그 중에서 영지의 ethylacetate fraction B와 fraction E에서 강한 활성을 보였다. Fraction B는 Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typtimurium 및 Pseudomonas aeruginosa 등에서 활성을 나타냈고 특히 Staphylococcus aureus와 Salmonella typtimurium에 대한 최소저해농도(MIC)는 0.8%(8,000 ppm)로 향신료로 사용되는 celery가 Staphylococcus aureus에 대하여 10,000 ppm인 것과 유사하였다. Fraction E는 Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Salmonella typtimurium에서 활성을 나타내었고, 특히 Staphylococcus aurues에 대한 최소저해농도(MIC)는 0.187%(1,875 ppm)로 향신료로 사용되는 rosmary가 Staphylococcus aureus에 대하여 MIC가 5,000 ppm인데 비하여 약간 강한 항균활성을 나타내었다.

• 대한화학회지
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• 제34권4호
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• pp.319-324
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• 1990

비스(아세틸아세토네이토)옥소바나듐(Ⅳ) 착물(VO (acac)$_2$)에서 하나의 아세틸아세톤(acac) 배위자가 디벤조일메탄(dbm)에 의해 치환되는 반응속도를 여러 가지 용매에서 분광광도법으로 측정했다. 반응조건을 [VO (acac)$_2$] 》[Hdbm]으로 했을 때 치환반응의 속도식은 다음과 같다. 속도 = k$_2$K[VO(acac)$_2$] [Hdbm] / (1 ＋ K[VO(acac)$_2$])여기에서 평형상수 K는 [VO (acac)$_2$dbmH] / [VO(acac)$_2$][Hdbm]이며, 반응속도상수 k$_2$는 dbmH착물내에서 Hdbm으로부터 acac-로의 양성자 이동속도에 해당하는 값이다.

• 대한화학회지
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• 제42권1호
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• pp.22-27
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• 1998

여러 가지 용매에서 N,N-dimethylaniline에 의한 coumarin 153과 coumarin 481분자의 형광소광효과를 조사하였다. 소광속도상수와 분자의 확산속도상수간의 관계로부터 소광과정이 분자의 확산과 어느정도 상호연관성을 갖고 있음을 알 수 있었다. slip boundary조건 보다stick boundary 조건을 적용하였을 때 분자확산 속도상수와 실험적인 소광속도상수와의 차이가 작게 나타났다. cyclohexane 과 같은 비극성용매에서의 소광속도 상수는 이론적인 확산속도상수 값과 오차범위 내에서 거의 일치하였으나 acetonitrile과 같은 극성용매에서는 소광속도상수는 확산속도상수보다 일관되게 작게 나타났다. 이것은 coumarin 분자의 형광소광이 분자간 확산에 의한 충돌 뿐만 아니라 분자내 전하분리와 같은 과정에 의해서도 진행되는 것으로 해석할 수 있다.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.381-386
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• 2002

The objective of this study was to link conformational changes of proteins at a water/methylene chloride interface to their destabilization upon emulsification. When 4 aqueous protein solutions (bovine serum albumin, $\beta$-lactoglobulin, ovalbumin, or ribonuclease) were emulsified in methylene chloride, considerable proportions of all the proteins became water insoluble aggregates. There were also noticeable changes in the compositions of their water-soluble species. A series of water/methylene chloride interfacial reactions upon the proteins was considered a major cause of the phenomena observed. Based on this supposition, the interfacial tension was determined by a Kruss DVT-10 drop volume tensiometer under various experimental conditions. It substantiated that the interfacial tension was high enough to cause the adsorption of all the proteins. Under our experimental conditions, their presence in the aqueous phase resulted in reductions of the interfacial tension by the degrees of 8.5 - 17.1 mN $m^{-1}$. In addition, dynamic changes in the interfacial tension were monitored to compare relative rates at which the adsorbed proteins underwent conformational, structural rearrangements at the interface. Such information helped make a prediction about how easily proteins would denature and aggregate during emulsification. Our study indicated that emulsifying aqueous protein solutions in organic solvents should be handled with care, due to adverse interfacial effects.

• 생약학회지
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• 제38권1호
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• pp.95-99
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• 2007

In order to find novel cancer chemopreventive agents, quinone reductase (QR) inductive activity of methanol extract of herbal medicines was examined using murine hepatoma, hepa1c1c7 cells. QR has been used as an anticarcinogenic marker enzyme in cancer chemoprevention study. The methanol extract of Alpinia officinarum (Zingiberace) showed showed significantly strong quinone reductase inductive activity compared to the control group. The methanol extract of Alpinia officinarum was successively fractionated with various solvents according to polarity. Hexane, ethyl acetate, buthanol and water fractions were obtained and theirs activities were assessed. The QR inductive effect was moved to the ethyl acetate fraction and was highly increased. The CD (concentration required to double the specific activity of QR) value of ethyl acetate fraction was 8.6 ${\mu}g/mL$. Alpinia officinarum also showed strong antioxidant activity. These results suggest that Alpinia officinarum can be developed as cancer chemopreventive agent.

• 환경위생공학
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• 제21권3호
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• pp.52-60
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• 2006

The ion exchange resins have been synthesized from chlormethyl styrene-1,4-divinylbenzene(DVB) with 1%, 2%, and 20%-crosslinking and macrocyclic ligand of cryptand 21 by copolymerization method and the adsorption characteristics of uranium(VI), copper(II) and dysprosium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, equilibrium time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The metal ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium$(UO^{2+}_2)\;>\;copper(Cu^{2+})\;>\;dysprosium(Dy^{3+})$ ion. The adsorption was in order of 1%, 2%, and 20% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvents.

• 대한화학회지
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• 제12권3호
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• pp.99-105
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• 1968

몇가지 ortho-hydroxy monoazo 化合物들을 合成하여 이것들을 遷移元素로 金屬化시켰다. 三酸化크롬, 酢酸銅 및 酢酸코발드를 이 金屬錯鹽生成反應에 使用하였다. 이 硏究에서 다음과 같은 事實들을 알 수 있었다. (1) 이 金屬錯鹽生成反應에서의 溶媒는 다른 여러가지 有機溶媒보다는 물이 가장 좋고, (2) 金屬錯鹽生成反應 混合液의 가장 適當한 液性은 pH=4.5~5.5程度 이었으며, (3) 이들 monoazo 金屬錯鹽의 물에 대한 溶解性은 主로 그 錯鹽의 組成에 달렸으나 어느 程度는 分子內의 黃酸基의 存在에 의하여서도 影響을 받는다. 그리고 (4) 分子當 두개의 ortho-hydroxy基를 가진 金屬錯鹽이 더 强한 結合能을 가지고 있다.

• Macromolecular Research
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• 제14권4호
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• pp.438-442
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• 2006

Novel sulfonated poly(aryl ether ketones) containing benzoxazole were directly synthesized by aromatic nucleophilic polycondensation using various ratios of 2,2'-bi[2-( 4-flurophenyl)benzoxazol-6-yl]hexafluoropropane to sodium 5,5'-carbonylbis(2-fluorobenzenesulfonate). The copolymers were soluble in polar aprotic solvents such as N-methyl-2-pyrrolidone, N,N-dimethylacetamide, and N,N-dimethylformamide at a relatively high solid composition (>15 wt%) and formed tough, flexible and transparent membranes. The membranes exhibited a degradation temperature of above $290^{\circ}C$. The exact dissolution times of these membranes at $80^{\circ}C$ in Fenton's reagent (3 wt% $H_2O_2$ containing 2 ppm $FeSO_4$) were undetectable, confirming their excellent chemical stability in fuel cell application. The membranes showed a moderate increase in water uptake with respect to increasing temperature. The proton conductivities of the membranes were dependent on the composition and ranged from $1.10{\times}10^{-2}$ to $5.50{\times}10^{-2}Scm^{-1}$ at $80^{\circ}C$ and 95% relative humidity (RH). At $120^{\circ}C$ without externally humidified conditions, the conductivities increased above $10^{-2}Scm^{-1}$ with respect to increasing benzoxazole content, which suggested that the benzoxazole moieties contributed to the proton conduction.