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        검색결과 305

        121.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Water-soluble cutting fluids are used for processing of aluminium materials. This short article describes properties of new additives of water-soluble cutting fluids for aluminium materials. Various Diels-Alder adducts of unsaturated fatty acids with acrylic acid of maleic anhydride were prepared by thermal reactions. Triethanolamine salts of Diels-Alder adducts of dehydrated castor oil fatty acids with acrylic acid or maleic anhydride showed excellent anti-corrosion property of aluminium materals. These thermal adducts showed anti-rust property for cast-iron chips, too.
        4,000원
        123.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We studied electrochemical characteristics of Langmuir-Blodgett(LB) films by using cyclic voltammetry with a three-electrode system. An Ag/AgCl as a reference electrode, a platinum wire as a counter electrode and LB film-coated indium tin oxide(ITO) as a working electrode were used to study electrochemical characteristics at a various concentration of NaClO4 solution. LB films were reduced from initial potential to -1350 mV, continuously oxidized to l650mV and returned to the initial point. The scan rate was l00mV/s. The monolayer surface morphology of the LB film have been measured by Atomic Force Microscope(AFM). As a result, We comfirmed that the microscopic properties of LB film by AFM showed the good orientation of momolayer molecules and the thickness of monolayer was 3.5-4.lnm. The cyclic voltammograms(CV) of the ITO-coated glass showed the peak potentials for the reduction-oxidation reation. LB films of 4-octyl-4'-(5-carboxypentamethyleneoxy) azobenzene(8A5H) / L-α-phosphayidyl choline, dilauroyl(DLPC) seemed to be irreversible process caused by only the oxidation current from the cyclic voltammogram. The current of oxidatation increased at cyclic voltammogram by increasing 8A5H density in LB films. The diffusivity(D) of LB films increased with increasing of a 8A5H amount and was inversely proportional to the concentration of NaClO4 solution.
        4,000원
        126.
        2002.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to know effect of Yackwa quality when sucrose fatty acid esters(S-570, S-970, S-1570) were added as an emulsifier. In mechanical characteristics, the Yackwa of sucrose fatty acid esters did greatly decrease the hardness, cohesiveness, springiness and gumminess, respectively, and increase the brittleness compared to the Yackwa of non-emulsifier and egg yolk. This tendency showed at the above level of 1.0% S-570, and 0.5% S-970 and S-1570, respectively. In sensory evaluation, the Yackwa of sucrose fatty acid esters increased the softness compared to the Yackwa of non-emulsifiers and egg yolk. There were significantly differences in the preference at 0.5% level of S-970 and 1.5% level of S-1570, respectively compared to other treatments. In conclusion, the 0.5% level of S-970 would be mostly useful level of emulsifier for making Yackwa.
        4,000원
        127.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methyl glycoside oleic acid polyester was successfully prepared from methyl glycosides and methyl oleate by emulsion interesterification in the presence of methyl fructoside oleic acid polyester as an emulsifier. Emulsion interesterification process was optimized to obtain 98% yield of methyl glycoside polyester within 3~5hr at temperatures as relatively low as 90~150℃ and 20~200mmHg pressure with a five-fold molar ratio of oleic acid methyl ester to methyl glycoside in the presence of 2(w/w)% potassium carbonate and 2O(v/v)% methyl fructoside polyester based on oleic acid methyl ester.
        4,000원
        128.
        2002.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We carried out this subject to observe photoisomerization using 1,2-dioleoyl-sn- glycero-3-phosphocholine(DOPC) mixed with fatty acid containing azobenzene group which has reversible to cis-trans by light irradiation. Spreading solutions for the LB films were prepared in chloroform(5.0×10-5mol/L).We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was prepared on the hydrophilic ITO(idium tin oxide) glass plate by LB method. As a result, the absorption spectra of 8A5H and DOPC of mixture LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in several solvents and mixture LB films.
        4,000원
        130.
        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
        131.
        2000.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investgated UV-Vis absorbance to observe the photoisomerization using the mixture solutions in chloroform and LB monolayers mixed with DLPE and 8A5H containing azobenzene which showed reversible cis-trans photoisomerization irradiated by alternate lights. We have found that the absorbance spectrums of the mixture solutions and LB monolayers were reversibly induced to cis-trans photoisomerization irradiated by alternate lights. In addition, the absorbance of both solution and LB monolayer mixed with 8A5H and DLPE were reversibly by alternate temperatures. As a results, the 1:1(by volume) mixture ratio of 8A5H and DLPE was more flexible and reversible cis-trans photoisomerization than the others.
        4,000원
        132.
        2000.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate fatty acid constituents and relative compositions in the fluid of the follicles, oviducts, uterine body and uterine body in Korean native cow, the fluids of the reproductive tract were analyzed using gas chromatography. The samples were taken from various reproductive tract of 23 Korean native cows. q. Caprylic acid (C8:0), myristic acid(C14:0), palmitic acid(C16:0), palmitoleic acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), linoleic acid(C18:2), arachidonic acid(C20:4) were found in the reproductive tracts of the cows, which made 8 kinds of fatty acid in total. 2. Palmitic acid, oleic acid, stearic acid were predominant with 35.67%, 24.98% and 17.52%, respectively. while low levels of fatty acids(<5%) were myristic acid, palmitoleic acid and caprylic acid with 1.75%, 1.28% and 2.69%, respectively. 3. Two kinds of polyunsaturated fatty acids, linoleic acid arachidonic acid were found in the reproductive tracts of cows. 4. Palmitic acid among saturated fatty acids and oleic acid among unsaturated fatty acids were the highest level in all of the reproductive tracts. 5. The Highest level of arachidonic acid was found in the uterine horn. 6. The sum of the palmitic acid and oleic acid were 61.72%, 63.72%, 57.66% and 57.65% for the fluid of follicle, oviduct, uterine horn and uterine body of the cows, respectively. 7. The relative compositions of palmitic acid, palmitoleic acid and caprylic acid were higher during the luteal phase than during the follicular phase. 8. The relative compositions of arachidonic acid was higher during the follicular phase in the fluid of uterine horn and uterine body of the cows. 9. The long chain fatty acid, the palmitic acid, stearic acid, oleic acid and linoleic acidshowed higher relative compositions during the follicular phase(86.49%∼95.51%) than during the luteal phase(85.64%∼88.93%).
        4,000원
        133.
        2000.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To investigate fatty acid constituents and relative compositions in the fluid of the follicles, oviducts, uterine ho군 and uterine body in sows, the fluids of the reproductive tract were analyzed using Gas chromatography. The samples were taken from various reproductive tract of 21 sows slaughtered. 1. Caprylic acid(C8: 0), capric acid(C10:0), lauric acid(C12:0), myristic acid(C14:0), palmitic acid(C16:0), plamitolele acid(C16:1), stearic acid(C18:0), oleic acid(C18:1), linoleic acid(C18:2) and arachidonic acid(C20:4) were found in the reproductive tracts of the sows, which made 10 kinds of fatty acid intotal. 2. Two kinds of polyunsaturated fatty acids, linoleic acid and archidonic acid were found inthe reproductive tracts. 3. Palmitic acid among saturated fatty acids and oleic acid among unsaturated fatty acids were the hihgest level in all of the reproductive tracts. 4. Palmitic acid, oleic acid and stearic acid showed higher rate with 44.89%, 23.69% and 14.36%, respectively, and lauric acid, capric acid, palmitoleic acid, arachidonic acid ad myristic acid showed lower rate with 0.62%, 1.13%, 1.65%, 1.97% and 2.24%, respectively in the reproductive fluid. 5. The highest level of arachidonic acid was found in the uterine horn. 6. The sum of the palmitic acid and oleic acid were 66.91%, 70.41%, 66.14% and 73.36% in the fluid of follicle, oviduct, uterine horn and uterine body, respectively. 7. The relative composition of arachidonic acid was higher during the follicular stage than during the luteal phase in the fluid of oviduct and uterine. 8. The long chain fatty acids such as the palmitic acid, stearic acid, oleic acid and linoleic acid showed higher relative compositions during the follicular phase(93.18%∼96.83%) than during the luteal phase(82.56%∼88.37%). 9. Caprylic acid, luric acid and palmitoleic acid were undetected in the fluid of all of the reproductive tracts during the follicular phase. Low relative compositions of capric acid, myristic acid andarachidonic acid were found during the follicular phase, while the low relative compositions (<5%)of capric acid, lauric acid, myristic acid, plamitoleic acid and arachidonic acid were found during the luteal phase.
        4,000원
        134.
        1999.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We carried out this subject to observe photoisomerization using 8A5H and phospholipid(DLPC) containing azobenzene group which has reversible to cis-trans by light irradiation. We investigated the photoisomerization and property of the monolayer film on quartz substrate prepared by the mixture of 8A5H and phospholipid deposited using Langmuir-Blodgett(LB) method. It was found that the absorption spectrum of the 8A5H and phospholipid LB monolayer was induced to photoisomerization by alternate light irradiation. And the absorbance of both the solution of mixtures of 8A5H-phospholipid and LB film was reversibly changed by the acid-base exposure and alternate temperatures.
        4,000원
        136.
        1999.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Maxwell displacement current(MDC) measuring technique has been applied on the study of monolayers of fatty acid. The displacement current was generated from monolayers on the water surface by monolayer compression and expansion. Displacement current was generated when the area per molecule was about 130a2. MDCs were investigated in connection with monolayer compression cycles. It was found that the current pulses were generated over the entire range of molecular area, and the maximum of MDC appeared at the molecular area just before the initial rise of surface pressure in compression cycles. We investigated the change in absorption spectra of the fatty acid(8A5H) monolayer LB film due to cis-trans photoisomerization. It was found that the absorption spectrum of the 8A5H LB film was induce to photoisomerization by alternate irradiation with UV and visible light irradiation.
        4,000원
        138.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        All the triacylglycerols including the molecular species having δ5-unsaturated fatty acids from the seeds of Pinus Koraiensis, were split into a mixture of diacylglycerols by a Grignard reagent prepared with allyl bromide without arousing acyl chains of a glycerol moiety to migration, and were also easily partially hydrolyzed to diacylglycerols by pancreatic lipase. (S)-(+)-(1-naphthyl)ethyl urethane(NEU) derivatives of the diacylglycerol mixture derived from the triacylglycerols were fractionated into sn-1, 3-, sn-1, 2- and sn-2, 3-DG-NEU by silica-HPLC and the fatty acid composition of these fractions was analysed. C18:1Ω9 is distributed evenly in the three positions of TG with C18:2Ω6 mainly located in sn-2 position, while δ5-unsaturated fatty acids such as δ5.9-C18:2, δ5.9.12-C18:3 and δ5.11.14-C20:3 are exclusively present in the sn-3 position. These results could be confirmed by 13C-NMR spectroscopy : the signals at δ173.231 ppm and δ172.811 ppm of the carbonyl carbon of acyl moieties indicate the presence of saturated acids and/or C18:1Ω9 (oleic acid) in the α(α')- or β- positions, and C18:2Ω6 including C18:1Ω9 in the β-position, respectively. In addition, the resonance at δ173.044 ppm suggested a location of δ5-unsaturated fatty acid moiety in the α(α')-position.
        4,000원
        139.
        1998.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to economical status, under-nutrition and over-nutrition coexist in preschool children in Korea. Subjects consumed more than RDA in most nutrients, and children in of the upper income class tended to have more nutrients than those of the low income class. Especially in case of energy, protein, fat, vitamin B2, and P there were significant differences among the different classes. The mean calorie compositions of carbohydrates, protein and fat were 57~59: 16~17: 26~27 and fat calorie percentage was higher than quantity recommended for Korean adults. Energy, protein, Fe, vitamin A, B1 and C intakes were taken mostly from plant food sources. In the upper income class group, intakes of protein and vitamin B2 from animal food sources were higher than in any other income classes. Intakes of iron, vitamin A, B1 and C were largely provided by plant food group. Especially 44-45% of vitamin A were taken from vegetable and fruits group, which indicated that about 50% of vitamin A intake was the form of β-carotene. Also compared with other groups, in the upper income class group, the intakes of energy, protein, Ca, p, vitamin B1 and vitamin B2 from cereal and potatoes were significantly lower, and those of Ca and P from milks and meats, fishes & eggs were significantly higher(p〈0.05). The mean fat intake in all subjects was 38~43g/day. Regardless of income class, oleic acid(6.6~8.4g) and linoleic acid(6.7~8.1g) were the most abundant fatty acids contained in the diet. The upper class group consumed significantly more total saturated fatty acids and total monounsaturated fatty acids(p〈0.05). In polyunsaturated fatty acids, there were no differences between 3 different income classes, but intakes of total Ω6 fatty acids in the upper class tended to be higher and those of total o3 fatty acids in low class tended to be higher. Therefore, Ω6/Ω3 tended to be higher in the upper class group. Regardless of income classes, P/M/S and Ω6/Ω3 ratios in all subjects were 0.9~l.3/1.0~1.1/1.0 and 5.2~7.4/1.0, respectively and were in a desirable range. Cholesterol intake of subject was 184-218 mg/day, which was comparable to the value of Korean adult intake.
        4,500원
        140.
        1998.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polyoxyethylene monooleate was prepared by addition of ethylene oxide to oleic acid. And also, polyoxyethylene monooleate type oil dispersant was prepared by blending polyoxyethylene monooleate, n-paraffine, sorbitan monooleate, sorbitan monopalmitate, and palm oil. Dispersion efficiency test was carried out by vertical shaking flask and swirling flask methods. Low toxic oil dispersant was prepared with polyoxyethylene monooleate, which has high biodegradability and excellent dispersion efficiency on crude oils and weathered W/O emulsions with high viscosity, and its dispersion efficiency was measured to various crude oils and weathered oils.
        4,000원