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        검색결과 13

        1.
        2001.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nb 첨가 Zr합금인 Zr-lNb합금과 Zr-lNb-lSn-0.3Fe함금의 석출물 및 산화 특성에 미치는 마지막 열처리 온도의 영향을 알아보기 위하여 최종 열처리 온도를 450˚C에서 800˚C까지 변화시켜 미세조직 및 산화 특성을 조사하였다. 부식 시험은 400˚C , 수중기 분위기에서 270 일 동안 실시하였으며 X-선 회절법을 이용하여 산화막 결정 구조를 분석하였다. 마지막 열처리 온도가 600˚C 이상일 때 두 합금 모두 β-Zr이 관찰되었으며 모두 재결정 이후 마지막 열처리 온도가 상승할수록 석출물의 면적 분율이 증가하는 경향을 나타내었다. 모든 열처리 온도 구간에서 Zr-lNb합금의 부식 저항성이 Zr-lNb-lSn-0.3Fe 합금에 비해 우수하였으며 두 합금 모두 재결정 이후 부식 저항성이 급격히 나빠졌다. 이는 600˚C 이후 형성된 β-Zr의 영향으로 밝혀졌다.
        4,000원
        2.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        These N-acyl amino acid surfactants is normally produced by reaction of acid anhydride with sodium l-glutamate hydrolysates under Schotten-Baumann condition i.e., in alkaline aqueous medium. To avoid using fatty acid chlorides, acylations were also carried out with the fatty acids themselves or with their methyl esters, but unfortunately these methods cannot be used in practice, dodecenyl succinic anhydride, was to be studied for their suitability as acylating agents the production if acylated glutamine hydrolysates. The surface activities including surface tension forming power, forming stability and emulsifying power were measured. The experimental results revealed that the products have a good emulsifying power. Thus, there derivatives will be expected to be used an emulsifying agent for O/W type cosmetic emulsion.
        4,000원
        3.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sodium N-acyl N-methyl taurates were synthesized by effectual acylation of fatty acid ethyl esters C(C12~C18) and N-methyl taurine. All the surface activities including krafft point, solubility, interface tension, foaming power, lime-soap dispersing ability and detergency were measured, and cmc was evaluated in dilute aqueous solution.
        4,000원
        4.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A synthesis of Dimer acid was studied from a tall oil fatty acid. Catalytic activity measured as reactant conversion in a autoclave reactor increase in accordance with the acidity. The optimization of process conditions were tested by an experimental design method. Optimization synthetic conditions of dimer acid and were reaction of tall oil fatty acid during 2 hour at 250℃, used of 7.3 wt% active clay and 1.2~1.4wt% water, and found reation pressure 8~9Kg/cm2. The maximum conversion rate was researched 74~76%.
        4,000원
        5.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Surface active properties of these aqueous Gemini surfactant solutions including surface tension, critical micelle concentration(cmc), foaming power, foam stability, emulsifying power and Krafft point were measured at given conditions. They showed excellent properties, being compared with conventional single-chain surfactants such as sodium dodecyl sulfonate(SDS). Their surface tensions in the aqueous solutions were decreased to 30~38 mN/m, which is lower than 39 mN/m of SDS, and their cmc values evaluated by surface tension method were 2.8×10-5~3.3×10-4 mol/L. These values were also much lower than that of SDS, 9.8×10-3 mol/L. The foaming power and foam stability, especially decyl and dodecyl compounds, were good and the emulsifying power in benzene or soybean oil was also excellent. All of the synthesized Gemini surfactants possessed good water solubility and their Krafft points were all below 0℃. As results, DDED and DDOD, Gemini surfactants which were synthesized are expected to be applied as foamers, emulsifiers and so on.
        4,000원
        6.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The emulsion stability of W/O emulsion prepared by D phase emulsification during storage and handling is studied by using phase diagrams. The process of D phase emulsification begins with the formation of isotropic surfactant solution, followed by formation of oil-in-surfactant (O/D) gel emulsion by dispersion of octamethylcyclotetrasiloxane(OMCS) in the surfactant solution. Polyols were essential components for this purpose. To understand the function of polyols, the solution behavior of nonionic surfactant/oil/water/polyol systems were investigated by the ternary phase diagrams of polyoxyethylene oleyl ether/OMCS/propylene glycol(PG) aqueous solutions. The addition of PG increased the solubility of oil in the isotropic surfactant phase. D phase emulsification method has been applied to a new type of cosmetics. By using this emulsification technique, O/W emulsion were formed without a need for adjust of HLB. Fine and stable W/O emulsions were prepared by D phase emulsion.
        4,000원
        7.
        1998.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        All the surface activities including surface tension, foaming power, foam stability, emulsifying power, dispersion effect, and detergency were measured and critical micelle concentration(cmc) was evaluated in dilute aqueous solution. The cmc evaluated by the Ring method was 10-3~10-4mol/L in case of monoesters, and 10-3~5.0×10-5mol/L in case of diesters, respectively. Surface tension of the aqueous solution was decreased to 45~50dyne/cm, showing the tendency that the ability of lowering the surface tension was dependent on increasing of carbon atom number in alkyl chain. Foaming power of all the monoesters was better than that of diesters. while foam stability of diesters was to the contrary. Emulsifying power of soybean oil or benzene was specially expected to be good for emulsifiers in industrial application fields. HLB values of monoesters and diesters evaluated by Griffin's method were in the range of 8 to 12. Dispersion property of ferric oxide was stable in the range of 4.5×10-5~5.0×-4mol/L in case of monoesters, and 10-5~10-4mol/L in case of diesters.
        4,600원
        8.
        1998.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Novel type surfactants containing two long-chain hydrophobic alkyl groups and two hydrophilic sulfonate groups were successfully synthesized by reactions of ethylene glycol diglycidyl ether with long-chain fatty alcohols, after then by reactions with 1,3-propane sultone and sodium hydride under THF solvent. All these compounds, so called Gemini surfactants, were purified by thin layer chromatography and column chromatography. Their structures were identified by FT-IR and 1H-NMR.
        4,000원
        9.
        1998.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One of the objectives of this study were to develop a process for manufacturing activated carbons from agricultural by-products(rice shells and saw dust) and another is to measure the iodine number, ash content and removal ratio of COD. The other is to compare those values with those of commercialized activated carbons. Agricultural by-products based activated carbons were manufactured through the steam-reaction method. A rotary kiln type furnace was used for both carbonization and activation. The optimum operating temperatures for carbonization and activation were 650℃ and 900℃, respectively. For the activated carbons produced under these conditions, the iodine number was 1,127mg/g. Especially, removal efficiency of COD was 61.5% for 40mg/L of wastewater and 30% for 150mg/L of SLS(Sodium Lauryl Sulfate).
        4,300원
        10.
        1998.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of long chain N-acyl amino acid type anionic surfactants were prepared by treating fatty acid chlorides with three kinds of amino acids, that is, sodium N-acyl-sarcosinates, sodium N-acyl-N-methyl-β-alaninates and sodium N-acyl-N-methyl-taurates in an alkaline solution. All prepared biodegradable surfactants were purified by thin layer chromatography and column chromatography, and identified their structures by spectral analysis.
        4,900원
        11.
        1993.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Anionic polyolic surfactants, alpha-sulfo fatty acids that straight long chain alkyl group has from 12 to 18 hydrocarbon numbers, was synthesized with sulfur trioxide-dioxane complex to good yields. New sodium alpha-sulfo long chain fatty acid monoglyceride were obtained by reaction that the ketalificaticn and esterification of glycerol, acetone and alpha-sulfo long chain fatty acid and hydrolysis respectively. These reaction products separated by column chromatography and their Rf values(Rf×100) were 19, 21, 24 and 26 respectively. These compounds were identified by infrared spectroscopy and 1H NMR spectroscopy.
        4,000원
        12.
        1992.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The synthesis and solution properties of polyglycerol alkyl ether(R12Gn) are described. The phase behavior, surface tension, cloud point and HLB value of polyglycerol dodecyl ether in aqueous solution and in mixed solution of surfactant /water /oil have been investigated and compared with values of polyoxyethylene dodecyl ether. The surface tension showed that R12Gn have sufficiently low values of surface tension and cmc to serve as useful polyoxyethylene alkyl ether. The mesophases appearing in the R12Gn systems were more stable in a high temperature range than the mesophases of polyoxyethylene alkyl ether systems. The cloud point and HLB data indicated that addition of one glycerol group was equivalent to the addition of three oxyethylene group units, as far as the hydrophilic property was concerned. The phase diagrams of the polyglycerol alkyl ether /dodecane /water systems showed that the solubilizing and emulsifying powers of R12Gn were greater than those of polyoxyethylene alkyl ether. It is concluded that the polyglycerol chain can be even more useful as hydrophilic group of nonionic surfactants than the polyoxyethylene chain.
        4,200원
        13.
        2011.09 KCI 등재 서비스 종료(열람 제한)
        본 연구는 실제 교량에서 차량 주행에 따른 가속도 계측 자료를 이용하여 교량의 고유진동수를 진동 모드별로 파악한 후, 수치 모델링을 통하여 유도된 동적하중에 따른 6차 모드까지의 고유진동수를 고려하여 처짐을 계산할 수 있는 산정식에 관한 것이다. 처짐 계산식은 모드중첩법에 의한 비감쇠 강제진동 이론을 이용하여 교량을 등속도로 이동하는 동적 주행하중에 의해 발생하는 처짐을 계산할 수 있도록 수치 모델링을 하였으며, 이를 검증하고 자동으로 계산할 수 있도록 하였다. 그리고, 제안된 처짐 계산식을 검증하기 위하여 콘크리트 교량을 대상으로 동적재하시험을 실시하여 처짐을 측정하고 이 값을 본 연구의 처짐 계산식의 결과와 비교하여 정확성 및 타당성 검증을 실시하였다. 이 결과, 본 연구에서 제시하는 처짐 계산식은 고유진동수를 고려하는 진동모드의 차수가 낮은 경우에 비교적 정확한 처짐을 예측하며, 주행속도에 따라서는 적용하는 진동 모드 차수에 의하여 처짐 예측의 정확도가 영향을 받는 것을 확인하였다. 그리고, 주행속도가 비교적 빠른 경우에 한하여 본 연구에서 제시하는 처짐 계산식은 진동 모드에 상관없이 비교적 정확하고 신뢰도가 양호한 계산 결과를 얻을 수 있는 것으로 나타났다.