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        검색결과 2,503

        2021.
        2001.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, there has been considerably interested in the development to new functional gemini type anionic surfactant, sodium bis-n-alkyl sulfonatosuccinate, had been synthesized through the addition reaction of sodium bisulfite to bis-n-alkyl maleate, in which water was azeotropically distilled by adding benzene to the reaction system, gave a good yield. All the surface activities including krafft point, surface tension, emulsion power and foaming were measure and cmc was evaluated in dilute solution. This results showed a lower ability in 27~30dyne/cm than single-chain surfactant with 32~35dyne/cm to surface tension. Also its cmc value much smaller in (6.5~10)×10-4mcal/l than single-chain surfactant with (40~45)×10-4mcal/l concentration. In foaming ability and foam stability of gemini surfactant had especially a good ability in approximately 100~150ml, and in emulsing power they exhibited a good emulsing phase and stability, and Krafft points were 0~10℃.
        4,000원
        2023.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In search for several fatty acid with unusual structure in vegetable oils, we have found that unknown peaks were shown on GLC in the analysis of fatty acids of the lipids from the pulp of ripened jujube (Zizypus jujuba var. inermis) fruits. These fatty acids were identified as a series of cis-monoenoic acids with Ω-5 double bond system such as C14:1Ω5, C16:1Ω5 and C18:1Ω5, including Ω-7 fatty acid as C16:1Ω7 and C18:1Ω7, by GLC, solid-phase extraction silver ion-column chromatographic, GLC-mass spectrometric and IR techniques. First of all, total fatty acid methyl esters were resolved into saturated and branched fatty acid, monoenoic acid, dienoic acid, and trienoic acid fraction, respectively, with 100% dichloromethane (DCM), DCM/acetone (9:1, v/v) 100% acetone, and acetone/ acetonitrile (97:3, v/v) solvent system. Unknown fatty acids were included in the monoenoic fraction and were confirmed to have cis-configuration by IR. Picolinyl esters of monoenoic fatty acids gave distinct molecular ion peak and dominant diagnostic peaks, for example, m/z 317, 220 and 260 fragment for cis-C14:1Ω5, m/z 345, m/z 248 and 288 fragment for cis-C16:1Ω5 and m/z 373, m/z 276 and 316 fragment for cis-C18:1Ω5. In this way the occurrence of cis-C16:1Ω7 and cis-C18:1Ω7 could be deduced from the appearance of prominent fragments as m/z 345, 220 and 260, and m/z 373, 248 and 280. Level of total Ω-5 fatty acids amounted to about 30% in the fatty acid composition with the predominance of C16:1Ω5 (18.7~25.0%), in the semi-ripened and/or ripened samples collected in September 14 (C16:1Ω5 ; 18.7%, C14:1Ω5 ; 3.6% and C18:1Ω5 ; 3.0%), September 22 (C16:1Ω5 ; 25.0%, C14:1Ω5 ; 1.4% and C18:1Ω5 ; 2.6%), and October 7 (C16:1Ω5 ; 24.7%, C14:1Ω5 ; 7.7% and C18:1Ω5 ; 2.5%). However, the lipids extracted from unripened jujube in July and August contain these unusual fatty acids as low as negligible. It could be observed that the level of Ω-5 fatty acids in the pulps increased sharply with an elapse of ripening time of jujube fruits. Other monoenoic fatty acids with Ω-7 series, C16:1Ω7 (palmitoleic acid) and C18:1Ω7 (cis-vaccenic acid) could be detected. And in the lipids of the kernel and leaf of jujube, none of Ω-5 fatty acids could be detected.
        4,200원
        2024.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Allylaliphatic carboxylate oligomers were prepared from polymerization giving allyl aliphatic carboxylates in the presence of potassium persulfate in methanol and the α-sulfonation of these allyl aliphatic carboxylates oligomers were carried by direct addition of dry sulfur trioxide. The dispersing performance of oligomer type anionic surfactants and SDS in the aqueous suspension of Fe2O3 and Tio2 particles were evaluated by particle size distribution and ξ-potential measurement. As results, the particles of Fe2O3 and Tio2 were flocculated by addition of small amount of oligomer type anionic surfactants and SDS, then the flocks redispersed by more addition oligomer type anionic surfactants and SDS. The dispersion and flocculation were observed in lower concentration range of oligomer type anionic surfactants than SDS.
        4,000원
        2025.
        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
        2026.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ultra-thin films of organic charge transfer complex were prepared on a hydrophilic substrate by Langmuir-Blodgett(LB) technique. In this study, the photoelectric properties of a LB film consisting of (N-docosyl quinolinium)-TCNQ(1:2) complex was investigated. The visible light(λ : 700 nm) of xenon lamp was illuminated on the LB films and light absorptivity and photoconductivity were observed. The photocurrent increased linearly and was saturated at the light intensity of 23 μW/cm2.
        4,000원
        2027.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Curing reaction was carried out with the acrylic resin (ACR) [n-butyl acrylate/atyrene/2-hydroxyethyl methacrylate/acetoacetoxyethyl methacrylate (AAEM)] synthesized before and a curing agent, hexamethoxymethylmelamine (HMMM). With rotational rheometer, the effect of catalysts on curing rate of acrylic resin/melamine was examined. Among the four catalysts used, p-toluene sulfonic acid showed the highest reactivity, and the optimum amount of catalyst was 0.5 phr. It was observed that in the ACR/HMMM curing reaction, gelation point was lowered with the increasing the amount of AAEM and HMMM in the ACR.
        4,000원
        2028.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An acrylic resin was synthesized with several monomers, styrene(St), 2-hydroxyethyl methacrylate(2-HEMA), n-butyl acrylate, methyl methacrylate, and acetoacetoxyethl methacrylate(AAEM) to prepare a high-solid coatings. Then, a high-solid acryl/melamine coatings was prepared by curing the acrylic resin with a curing agent, hexamethoxymethylmelamine(HMMM). The curing behavior of the acrylic resin with HMMM was investigated by the Ozawa method using DSC. For AAEM/HMMM and 2-HEMA/HMMM curing reactions, activation energies were 33.01 and 27.12 kcal/mol and frequency factors were 9.54×1015 and 1.53×1013 min-1, respectively. From the results, it was found out that 2-HEMA showed higher reactivity with the curing agent than AAEM.
        4,200원
        2029.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylic quarternary polymers were synthesized to prepare high-solid coatings. Acrylic resins were synthesized by the radical polymerization of n-butyl acrylate, methyl methacrylate, 2-hydroxyethyl methacrylate and acetoacetoxyethyl methacrylate. From the results of experiment on reaction condition to get high-solid acrylic resins with 70% solid content and viscosity of 1200cps, it was found that di-tert-amyl peroxide among the four types of initiators have lower viscosity and higher degree of conversion. The optinum initiator amount, chain transfer agent, reaction temperature and the dropping time were 5wt%, 4wt%, 150℃ and 5hrs, respectively.
        4,000원
        2030.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Eu(III) exhibits one electron-transfer reduction at E1/2 = -0.564 V(vs. Ag/AgCl) and the hypersensitive peak at 615 ㎚ corresponding to 5D0→7F2 transition in 0.1 M LiClO4 aqueous solution. Upon the addition of 2,6-pyridine dicarboxylic acid(PDA) to the Eu(III) aqueous soultion, the reduction potential shifts negatively and the PDA, and the Eu(III)-PDA complex emits great fluorescence than free-Eu(III) ion at 615 nm. The results are interpreted in term of the electrochemical and spectrofluorometric studies.
        4,000원
        2031.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        White emission is important for applying organic EL devices to full-color flat panel display and backlight for liquid crystal display. In order to obtain white emission, the use of a light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) (Zn(BTZ)2 was known to emit white light with a broad electroluminescence. In this study, the electroluminescent characteristics of Be(BTZ)2 and Mg(BTZ)2, as well as Zn(BTS)2 were investigated using organic electroluminescent devices with the structure of ITO/TPD/ Be(BTZ)2, Mg(BTZ)2, or Zn(BTZ)2/Al. It was found that the device containing Be(BTZ)2 showed the highest power efficiency.
        4,000원
        2032.
        2001.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Theoretical model has been studied for the transport phenomena of molecules in the system where an electric potential is applied to the system in the axial direction. The effect of electrophoretic convection in the polymeric media is significantly contributed to separate large ionic-molecules because the conformation of large ionic-molecule quickly orients in the field direction. The dependence of the transport in the polymeric media upon field intensity and molecular size aids in understanding the transport of large ionic-molecule in the system, since the convective velocity of large ionic-molecule is accelerated inside a porous material. The transport distance of individual large ionic-molecule can be predicted using the reptation theories.
        4,000원
        2033.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cellulose tosylate(CT) was prepared by reaction of cellulose with p- toluenesulfonylchloride in DMAc/LiCl homogeneous system. In order to study a reversible photoisomerization of disperse red 1(DR-1) attached on natural polymer, cellulose tosylate containing DR-1(DR-1/CT adduct) was prepared at 110℃ in DMAc, and the changes of UV/Vis spectra of its solutions and thick film were investigated by alternate irradiation technique. Form the UV/Vis spectra of DR-1/CT adduct dissolved in cosolvents, such as DMAc, DMAc/THF, DMAc/benzene, and DMAc/chloroform and irradiated with 360 nm and 450 nm ligths, we found out changes of UV/Vis spectra were reversible in all solvents systems and we found out changes of UV/Vis spectra were reversible at thick film, also.
        4,000원
        2034.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dual-actions are the most recently used delivery system in drug study. Dual-action agents are unique chemical entities comprised of two different type of antibacterial compounds covalently linked together in a single molecule in such a way that both components are able to exert their bactericidal properties. Crosslinked sulfadiazine-sulfanilamide such as antibiotics is synthesized by synthetic handle with glutaraldehyde. As a result, New synthetic antibacterial agent exhibited the broad antibacterial activities against gram(+) and gram(-) of 4 strains and a long durability supposing that the stomach and blood.
        4,000원
        2035.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylic pressure sensitive adhesives of n-butyl acrylate, 2-ethyl acrylate, methyl acrylate, vinyl acetate, acrylic acid, acrylonitrile and 2-hydroxyethyl acrylate were synthesized and basic physical properties of pressure sensitive adhesives with increasing the contents of 2-hydroxyethyl acrylate were investigated. 2-Hydroxyethyl acrylates effects on glass transition temperature, viscosity, hardening time and peel strength. Glass transition temperature(Tg) decreased with increasing the contents of 2-hydroxyethyl acrylate. Viscosity and hardening time were increased with increasing the contents of 2-hydroxyethyl acrylate. On the other hands, peel strength increased with increasing the contents of 2-hydroxyethyl acrylate up to 6 wt% and the decreased at further higher contents of 2-hydroxyethyl acrylate. In peel test, interfacial failure was occured in 8 wt% and 10wt%.
        4,000원
        2036.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Monodisperse polymer particles have many industrial applications such as surface coatings for metal panels, chromatographic media, spacers for liquid crystal display panel, and fillers for cosmetics, etc.. Micron-size monodispersed poly(methyl methacrylate) particles were prepared by dispersion polymerization in methanol medium in the presence of poly(vinyl pyrrolidone) and 2,2'-azobis(isobutyronitrile) as steric stabilizer and initiator, respectively. Effects of polymerization parameters, such as monomer and initiator concentration, stabilizer type and concentration, solvent composition on average particle size and size distribution were studied.
        4,000원
        2037.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the property of formation of mono-vesicle(designated nano-some) with using of the combined co-emulsifiers and phospholipid. Nano-some was prepared with hydrogenated lecithin(HL) and diethanolamine cetyl phosphate(DEA-CP) by swelling reaction. Kojic acid and kojic dipalmitate could be made stabilization by nano-some system using microfluidizer(MF). Nano-some has a good affinity to skin by means of this system. The composition was compounded by 2% of hydrogenated lecithin (phosphatidyl choline contained with 75%, 0.5% of DEA-CP and 0.5% of diglyceryl dioleate (DGDO). To make nano-some, several conditions of MF have to be considered as follows. The optimum pH was 6.0. The pressure was 10,000psi and passage temperature was at 306℃. The nano-some base was passed to homogenize continually 3 times through MF. The Particle size distributions of the vesicles were with in 57~75.7nm(mean 66nm) by measuring the Zetasizer-3000. Zeta potential of vesicles with 3 times passage through MF was -24.8mV. Formations for nano-some vesicle certificated photograph by scanning electric magnification (SEM). Stability of nano-some was very good for 6months. The turbidity was very good transparency compared nano-some with liposome. It was formed the mono vesicle in the opposite direction to be formed the multi-lamellar vesicle of liposome.
        4,000원
        2038.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two-component polyurethane flame-retardant coatings were prepared by blending trichloro aromatic modified polyesters(TCMPs) and polyisocyanate. TCMPs were synthesized by polycondensation of trichlorobenzoic acid(TCBA), a flame-retardant component, with adipic acid, 1,4-butanediol, and trimethylolpropane. The content of TCBA was varied in 10, 20, and 30 wt% for the reaction. These new flame-retardant coatings showed various properties comparable to other non-flame-retardant coatings. Moreover, we carried out the combustion test and the flammability test for our flame-retardant coatings. The results of vertical burning test for the coatings containing more than 20 wt% of TCBA were determined as 'no burn'. The results of flammability test for the coatings with 20 wt% and 30 wt% of TCBA contents indicated the limiting oxygen index(LOI) values of 25% and 28% respectively, which implied relatively good flame retardancy.
        4,000원
        2039.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To prepare an environmental friendly high-solid coatings an acrylic resin containing 80% of solid content was synthesized by addition polymerization of caprolactone acrylate, n-butyl acrylate, ethyl methacrylate, and 2-hydroxyethyl methacrylate. The conversion was 78~93% and the prepared resin's physical properties are as follows: viscosity, 212~3424cps: Mn 1740~2400. There was a trend that viscosity and molecular weight of the resin increased with Tg, but no direct proportionality was observed.
        4,000원
        2040.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyimide is a well-known organic dielectric material, which has not only high chemical and thermal stability but also good electrical insulating and mechanical properties. In this research, we have synthesized a polyamic acid(PAA), which is a precursor of the polyimide. To obtain the optimum conditions of polyamic acid alkylamine salt(PAAS) Langmuir-Blodgett(LB) film deposition, the π-A isotherms were examined by varying subphase temperature, barrier moving speed and spreading amount of solution. Film formation was verified by measuring transfer ratio, absorption of UV/vis spectra and scanning electron microscope(SEM) images.
        4,000원