• 제목/요약/키워드: Various Solvents

검색결과 784건 처리시간 0.022초

친환경 제설제 개발 현황 (Current Status of Eco-Friendly Deicing Material Development)

  • 서호성;박병흥
    • 융복합기술연구소 논문집
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    • 제6권2호
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    • pp.25-28
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    • 2016
  • Recently, due to the climate change by global warming, the amount of snow has increased. The situations were demanded to use many snow removal materials. The snow removal materials that used in Korea were solid chloride deicing material. That is calcium chloride($CaCl_2$) and sodium chloride(NaCl). Solid chloride baesd snow removal materials have various property, for example good freezing point depression, deliquescence and economical solvents. However, there are problems such as water pollution, high corrosiveness and ecocide. For such reason, development of eco-friendly deicer was required obligatorily. This study investigated development situation of eco-friendly deicer materials.

키토산 C-6에 Amine기를 갖는 Polyamino Acid 유도체의 합성과 생물학적 활성에 관한 연구 (A Study on the Synthesis and Biological Activity of Polyamino Acid Derivatives have Amine Group on to Chitosan C-6)

  • 류성렬
    • 한국응용과학기술학회지
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    • 제28권4호
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    • pp.438-448
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    • 2011
  • Chitosan is widely used in cosmetics and medical fields. Special emphasis has been put on the chemical modification of chitosan to explore its full potential. We have described the synthesis and biological activity of novel peptide amino acid derivatives. The polyamino acid derivatives were synthesized by introducing alkylamine functional group on chitosan at C-6. The poor aqueous solubility of chitosan derivatives hinder both pharmacological studies and pharmaceutical development. To make amino acid coupled chitosan derivatives with improved biological effect and solubility, some attempts have been taken to consist of amino peptide group like aspartic acid and phenylalanine-aspartic acid derivatives onto chitosan C-6. The resultingly substituted chitosan was characterized by solubility in various solvents. We measured chitosan derivatives with $^1H$-NMR and $^{13}C$-NMR. Also, We were investigated on the physical properties and biological activities of these products.

산초와 초피 잎의 항균활성 (Antimicrobial Activities of Zonthoxylum schinifolium and Zanthoxylum piperitum Leaves)

  • 김정;조영수;서권일;주옥수;심기환
    • 한국식품저장유통학회지
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    • 제7권2호
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    • pp.195-200
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    • 2000
  • Yields of various solvent extracts for Zanthoxylum schinifolium and Z. piperitum leaves were higher in ethanol extract layer. Ethanol Extract in sancho and chopi leaves was fractionated with different solvents, such as hexane, chloroform, ethyl acetate, butanol and water, yields of hexane fraction was higher. In the solvent extracts using methanol, ethanol, hexane, chloroform, and water, ethanol extract showed the most effective antimicrobial activities. Ethanol extract in sancho and chopi leaves was fractionated, the most antimicrobial activities of sancho leaf were ethyl acetate fraction, and chopi leaf were chloroform fraction.

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4차 아민이 치환된 아닐린의 고리화반응 메카니즘 및 Pyrrolo[1,2-a]benzimidazoquinone 유도체의 합성에의 응용 (Mechanistic Studies for the Cyclization of t-Amine Substituted Anilines and Their Utilization to the Synthesis of Pyrrolo[1,2-a]benzimidazoquinone Derivatives)

  • 이창희;백호진;김국진;조규욱;오경택
    • 대한화학회지
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    • 제39권5호
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    • pp.408-413
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    • 1995
  • A few t-amine substituted anilines and amides were synthesized and cyclized to pyrrolo[1,2-a]benzimidazole by heating in various solvents having different polarity. Subsequent nitration of cyclized compound followed by reduction and oxidation of resulting amine afforded quinone such as 7 in 14% yield. The formation of imidazole moiety by thermal cyclization was independent on the solvent polarity. The regiochemistry for the nitration of 4 was unambiguously determined by chemical transformation.

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항생물질 현탁액중에서 Erythrosine의 흡수에 관한 연구 (Studies on the Adsorption of Erythrosine in the Suspension of Antibiotics)

  • 백우현;송영준;김정우;김종갑
    • 약학회지
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    • 제23권3_4호
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    • pp.133-140
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    • 1979
  • The adsorption of erythrosine in the aliphatic alcohols by antibiotics such as ampicillin anhydrous, ampicillin trihydrate, amoxicillin trihydrate, cephalexin monohydrate was studied. The adsorption isotherms were all described with Freudlich equation. From the various experimerts, it was found that the adsorption of erythrosine by antibiotics in the aliphatic alcohols was affected by the solubility of adsorbents. The adsoption in the mixture of aliphatic alcohols and water is related with the dielectric constant of mixed solvents. According to increase in the pH values of aqueous solution, the adsorption of erythrosine for antibiotics is decreased, but increased in the mixture of aliphatic alcohols and water. The adsorption of erythrosine in the suspension of antibiotics showed a correlation with the temperature. Colloidal silica which is used as stabilizer had a favorable effect on the adsorption of erythrosine in the suspension of antibiotics.

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제한효소에 대한 용매의 영향 :소수성 용매에 의한 PvuII 특이성 변화 (Solvent Effect on Restriction Endonuclease : Alteration of Specificity of Restriction Endonuclease PvuII in Hydrophobic Solution)

  • 김희정;이강민
    • KSBB Journal
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    • 제9권1호
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    • pp.63-71
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    • 1994
  • During the last decade enzyme reaction in organic solvent has been studied to show that specificity in buffer is different from that in organic solvent. The specificity of restriction enzyme was effected by various factors such as ionic strength, salt organic solvent and temperature. In this study, restriction enzyme PvuII which is used most frequently in genetic engineering and the substrate was vector pGEM3 whose sequence was already known were used. As a result the recognition sequence site was changed in the presence of organic solvents whose Log P are -1.5∼0. Their specificities were contrast with activities were contrasted. Specificities were not changed in organic solvent easily in inactivating enzyme. We think that the enzyme recognition site was not changed randomly but by preferential order. A recombinant vector which does not contain typical cleavage site CAG↓CTG was cleaved in 20% ethanol solution. This result might show that restriction enzyme could be used to cleave at unusual sites by changing the reaction conditions.

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Synthesis of Thermally Reduced Graphene Sheets Using Poly(ionic liquid)

  • 이현욱;김태영;서광석
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.256-256
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    • 2010
  • It is demonstrated that graphene sheets are produced via thermal reduction of graphene oxide (GO) in the presence of imidazoium-based poly (ionic liquid) (PIL). PILs plays an important role in minimizing the reduction time and dispersing graphene sheets in organic solvents. In addition, as-obtained graphene sheets are found to be functionalized with PIL molecules by the strong interaction of PIL and the graphene, as analyzed by various physical methods such as atomic force microscopy (AFM), X-ray photoelectric spectroscopy (XPS) and Raman spectroscopy. Such a strong interaction allows the successful production of graphene/PIL composites, in which their electrical properties are controllable by the loading level of graphene in the PIL matrix.

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이온성 액체를 이용한 수계 양자 점 합성 (Aqueous synthesis of quantum dots using functionalized ionic liquid)

  • 최숙영;김태영;서광석
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.254-254
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    • 2010
  • We report aqueous synthesis of cadmium telluride (CdTe) quantum dots(QDs) using imidazolium-based ionic liquids with various functional groups. The functinalized ionic liquids were designed to have thiol groups, and then phase transfer with aqueous or organic solvents can be adjusted by changing side chain lengths of the cation and the choice of anion. The quantum yield was obtained IL-functionalized CdTe QDs reached up to 40% by post-treatment method.

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Gum-Resinosis in Mangifera indica

  • Marimuthu, Jayabalan;Rajarathinam, Kaniayappanadar;Jayakumar, Muthukrishnan;Kil, Bong-Seop;Kulandaivelu, Govindasamy
    • The Korean Journal of Ecology
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    • 제24권2호
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    • pp.121-123
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    • 2001
  • Gums, resins and gum-resins represent a variety of plant exudates that are highly prized and are extensively used in various industries. The usage of water soluble gums is growing at faster rate as they are excellent suspending agents, dispersants stabilizing agents, emulsifiers and gel forming agents. The gums are made up of carbohydrate polymers, composed of sugar units glycosidically condensed to form large molecules. Resins are non-volatile products, and oxidative products of terpenes or fatty acids, and are of greater commercial importance. They are soluble in water and contrasted with gums, soluble in organic solvents only.

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INVESTIGATION OF TRIPLET STATE AND SINGLET OXYGEN DYNAMICS OF BENZOPHENONE IN POLAR AND NONPOLAR SOLUTIONS WITH TIME-RESOLVED TWO-COLOR THERMAL LENSING METHOD

  • Ha, Jeong-Hyon
    • Journal of Photoscience
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    • 제3권3호
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    • pp.141-145
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    • 1996
  • The heat generated by nonradiative decay dynamics induces thermal lens effect. From such an effect, photodynamic properties of solutions can be investigated with two-color pulsed thermal lens experiments which have the time resolution of down to nanoseconds. In this study, using nanosecond two-color thermal lens method, we investigated the triplet state of benzophenone and the singlet oxygen state dynamics in various oxygen concentration solvents. The measured triplet state lifetimes, singlet oxygen relaxation times and singlet oxygen formation quantum yields are in good agreement with the reference values. From these parameters the existence of the triplet exciplex formation between benzophenone and benzene is proved, and it is also suggested that the relaxations of triplet states of benzophenone undergo coupled dynamics with some of singlet oxygens in oxygen-rich conditions.

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