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        검색결과 2,636

        1921.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the electrochemical properties for Langmuir-Blodgett (LB) films mixed with fatty acid (8A5H) and phospholipid (DLPE, DMPC, and DPPA). LB films of 8A5H monolayer and 8A5H-phospholipid mixture were deposited using the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured using cyclic voltammetry with three-electrode system, an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode at various concentrations(0.1, 0.5, and 1.0 mol/L) of NaClO4 solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV and measured to the initial point. The scan rate was 50, 100, 150 and 200 mV/s, respectively. As a result, LB films of fatty acid and phospholipid (8A5H/DLPE and DPPA) appeared irreversible process were caused by only the reduction current from the cyclic voltammogram and LB film of 8A5H-DMPC mixture was found to be caused by a reversible oxidation-reduction process.
        4,000원
        1922.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Theoretical total nitrogen removal efficiency and reactor volume ratio in oxic-anoxic-oxic system can be found by influent water quality in this study. The influent water quality items for calculation were ammonia, nitrite, nitrate, alkalinity, and COD which can affect nitrification and denitrification reaction. Total nitrogen removal efficiency depends on influent allocation ratio. The total nitrogen removal follows the equation of 1/(1+b). Optimal reactor volume ratio for maximum TN removal efficiency was expressed by those influent water quality and nitrification/denitrification rate constants. It was possible to expect optimal reactor volume ratio by the calculation with the standard deviation of ±14.2.
        4,000원
        1923.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Benzoxazolo carbocyanine compounds were synthesized by condensation of a suitable ortho-ester with an appropriately substituted 2-methylbenzoxazole in the presence of triethylamine. This compounds used as green sensitizing dyes in photographic emulsions. The compounds are characterized by fast atom bombardment mass spectrometry. The values(m/z) of structurally significant ions observed in FAB spectra. It was showed tentative fragmentation pattern in FAB spectroscopy of HN(C2H5)3 cations in glycerol/trifluoroacetic acid matrix.
        4,000원
        1924.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        From the result of pharmacetical characteristics and analysis of Green-tea extract, it could obtain some conclusions as follows. The extract experiment of Green-tea appeared about 10%-extraction ratio as semi-solid state, and after dried in freezing from Green-tea extract of semi-solid state, it obtained about 65% Green-tea extract as solid state. In the results on antimicrobial experiment of Green-tea extract, number of S-typhimurium and fungus in microbe decreased more and more according to the time passage. This phenomenon could show that Green-tea extract keeps antimicrobial effect. In the results on antioxidation experiment of Green-tea extract, DPPH scavenging activity of free radical showed that Green-tea extract appears more remarkable reduction ability than reference samples. This phenomenon means that antioxidation of Green-tea extract appears higher than Vitamin-C and BHA sample. In the results on intrument analysis, the fatty and aromatic components of aniline, acetaldehyde, acetic acid, trichloroethylene, caffeine etcs from Green-tea extract was detected with GC/MS analysis and inorganic components of Ca, Mg, Cu, Mo, Sb, Ti etcs from Green-tea extract was detected with ICP/OES analysis.
        4,000원
        1925.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The high-solid coatings were prepared by blending the synthesized acrylic resin in the previous paper, and hexamethylene diisocyanate-trimer and curing it at room temperature. The characterization of the films of the prepared coatings was performed. The 60˚ specular gloss, impact resistance, cross-hatch adhesion, and heat resistance of the films proved to be good, and the pencil hardness, drying time, and pot-life proved to be slightly poor. From a viscoelastic measurement using a rigid-body pendulum, curing was accelerated with the Tg value.
        4,000원
        1926.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to obtain the maximum flame retardancy as well as the minimum deterioration of physical properties of PU flame-retardant coatings, chlorine and phosphorus functional groups were introduced into the pre-polymer of modified polyesters. In the first step, the tetramethylene bis(orthophosphate) (TBOP) and neohexanediol dichloroacetate (DCA-adduct) intermediates were synthesized. In the second step, 1,4-butanediol and adipic acid monomers were polymerized with the two kinds of intermediates to obtain copolymers. The modified polyesters containing chlorine and phosphorus (ATBA-10C, -20C, and -30C) were synthesized by adjusting that the content of phosphorus compound was fixed as 2wt% and the contents of chlorine compound (dichloroacetic acid) were varied as 10, 20, and 30wt%. Average molecular weight and polydispersity index of the preparation of ATBAs were decreased with increasing DCA content because of the increase in hydroxyl group that retards reaction.
        4,200원
        1927.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, magenta coupler was prepared by the reaction of 1-(2,4,6-Trichlorophenyl)-3-(5-amino-2-chloroanilino)-5-pyrazolone with 2,4-di-tert-pentyl-phenoxy butanoyl chloride in the presence of pyridine. The product was identified by using various analytical tools such as melting point, elemental analyzer, IR spectrophotometer, UV-Vis spectrophotometer and GC-mass spectrometer. The reaction of magenta coupler with CD-3 (color development agent) was shown magenta color.
        4,000원
        1928.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Acrylic resins (HSCs : EA/EMA/2-HEMA/CLA) which contain 80% solid content were synthesized by the copolymerization of monomers (ethyl acrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate) and functional monomer (caprolactone acrylate : CLA) which improves the crosslinking density and physical properties of films. The physical properties of the prepared acrylic resins (HSCs) containing CLA, are as follows: viscosity 1440~2630 cps ; Mn 1590~1660 ; and conversions, 81~86%, respectively. From the correlation of Tg values, viscosities, and Mn of the HSCs, it was found thst viscosity and Mn increased with Tg value.
        4,000원
        1929.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Modified polyesters (TTBA-10C, -20C, -30C) that contain phosphorus and chlorine were synthesized by the condensation polymerization of tetramethylene bis(orthophosphate), neohexanediol trichlorobenzoate, 1,4-butanediol and adipic acid, in which tetramethylene bis(orthophosphate) and neohexanediol trichlorobenzoate were prepared previously in our laboratory. In this study, two-component flame-retardant polyurethane coatings (TTBA-10C/HDI-trimer=TTHD-10C, TTBA-20C/ HDI-trimer= TTHD-20C, TTBA-30C/HDI-trimer= TTHD-30C) were obtained by curing at room temperature with the synthesized TTBAs and hexamethylene diisocyanate (HDI)-trimer as a curing agent. The obtained TTHDs were made into coating samples and used as test samples for various physical properties. The physical properties of the flame-retardant coatings containing chlorine and phosphorus groups were generally inferior to those containing only phosphorus group. Flame retardancy was tested by vertical and horizontal combustion method, and 45˚ Meckel burner method. Since the retardancy of flame-retardant coatings containing chlorine and phosphorus groups was better than that containing only phosphorus group, it could be concluded that the retardancy by the synergism effect of chlorine and phosphorus groups exhibited.
        4,000원
        1930.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical parameters(μs, μa, μt, γ, σ). The value of scattering coefficient μs is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.
        4,000원
        1931.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Methanol and formaldehyde were produced directly by the partial oxidation of methane. The catalysts used were mixed oxides of late-transition metals, such as Mn, Fe, Co, Ni and Cu. The reaction was carried out at 450℃, 50 bar in a fixed-bed differential reactor. The prepared catalysts were characterized by XRD, TPD and BET apparatus. Of the catalysts, A-Mn0.2-6, which contains 0.2 mole of Mn and calcined at 600℃, showed the best catalytic activity: 3.7% methane conversion, and 30 and 28% methanol and formaldehyde selectivities, respectively. The catalytic activity was changed with the content of Mn and the calcination temperature. Catalytic activity increased with the specific surface areas of the catalysts. With XRD, it was found that the structure of the catalysts are changed with calcination temperature. Through O2-TPD experiment, it was found that the catalysts showing good catalytic activity showed O2 desorption peak around 800℃.
        4,000원
        1932.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kelvin equation is revisited, which accounts for important phenomena observed frequently in nano-dispersion systems. They include vapor pressure increase for curved interfaces, nucleation, capillary condensation, Ostwald ripening and so on. The smaller the radius of curvature is, the more significant Kelvin equation becomes. Therefore, its meaning, curvature effect, and importance are examined and discussed.
        4,000원
        1933.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we prepared porous cation exchange membrane using polystyrene such as, EPS (expanded polystyrene), SAN (styrene acrylonitrile copolymer) and HIPS (high impactive polystyrene). These polystyrenes were sulfonated by acetyl sulfate to make porous cation exchange membrane such as, SEPS, SSAN, SHIPS. SEM was employed to confirm porous structure of membrane, and IR spectroscopy was used to confirm sulfonation rate of ion exchange membrane. Water and methanol content were also increased with amount of sulfuric acid in reactants. SSAN-20 showed the highest value in water and methanol content. Fixed ion concentration and conductivity was also increased with an amount of sulfuric acid in reactants. Methanol permeability for SEPS-20, SSAN-20, SHIPS-20 was found to be 1.326 × 10-5 cm2/s, 1.527 × 10-5 cm2/s and 1.096 × 10-5 cm2/s respectively. From the result of electrodialysis experiment in 0.03 M Pb(NO3)2 aqueous solution, anion exclusion and cation selection effects were confirmed.
        4,000원
        1934.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Solvent-free low foaming scouring agents (LFSC) were prepared by blending of 2-ethylhexylaminoethyl sulfate (2-EHAS), POE(10) octadecylbenzyl- ammonium chloride (POBAC) and Sedlan FF-200 (FF-200). As the results of several tests, 2-EHAS/POBAC/FF-200/water (8g/12g/20g/60g) mixture (LFSC-5) showed good cleaning power, penetrating ability and stability to alkali, and gave less problem in water pollution. The foaming power of LFSC-5 measured by Ross and Miles method was 8mm foam height immediately after foaming, and that measured by Ross and Clark method was less than 300mm foam height at 30℃, and 18mm at 80℃. As a result, LFSC-5 proved a good low foaming scouring agent for fiber.
        4,000원
        1935.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to synthesis basic resins for the preparation of PU flame-retardant coatings that contain phosphorus and chlorine. After synthesizing intermediates of tetramethylene bis(orthophophate) (TMBO) and neohexanediol trichlorobenzoate (TBA-adduct), the condensation polymerization was performed with the intermediates, 1,4-butanediol, and adipic acid to obtain four-component copolymers. In the condensation polymerization, the content of phosphorus was fixed to be 2%, and the content of trichlorobenzoic acid (TBA) that provides chlorine component was varied to be 10, 20, and 30wt%, and we designated the prepared modified polyesters containing chlorine and phosphorus as TTBA-10C, TTBA-20C and TTBA-30C. Average molecular weight and polydispersity index of the prepared TTBAs decreased with increasing TBA content because of the increase in the number of hydroxyl groups that retards reaction. We found that the thermal stability of the prepared TTBAs increased with chlorine content at high temperatures.
        4,200원
        1936.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Flesh wasters from tannery create major environmental problems. Despite their considerable fat content, these waster do not find important usage. Their disposal is also troublesome and costly. We have investigated the possible use of this fat as the production of biodiesel(fatty acid methyl esters) by transesterification using with fossil fuels. The fat released the waste by boiling water under the optimal condition (i.e., temperature, 120℃; decompression, 200mbar) and used to dry without refining for the production of fatty acid methyl esters. Under the optimal condition, the experimental value of biodiesel yield was about 96%. The result of the chemical and GC analysis showed fatty acid composition and characteristics of biodiesel. Evaluation of the product indicated that it was suitable for use as a biodiesel fuel. In result of this experiment oil extract from fleshing process can be transformed into an environmentally affination fuel, to provide economical and ecological profits.
        4,000원
        1937.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The transesterification of vegetable oils into Biodiesel at 60℃ was performed on the rotary viscometer. The overall yield(%) of fatty acid methyl ester from canola oil at optimum conditions was 95%. The viscosities of fatty acid methyl esters were predicted by Orrick and Erbarr's model. The overall yield increased as the viscosities of fatty acid methyl esters decreased. The limiting molar ratio of methanol to oil appeared to be 1:5. The content of sodium hydroxide as the optimum catalyst appeared to be 0.5wt%.
        4,000원
        1938.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and 5.73 μm at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the SiO2/Na2O mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of SiO2/Na2O.
        4,200원
        1939.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In general, water treatment sludge (WTS) had high concentration of heavy metal, thus it made the reuse or recycling of WTS difficult. The optimal solidification conditions for maximum suppression of heavy metal elution from WTS were decided in this study. Under the optimal solidification conditions (i.e., temperature, 320℃; ratio of WTS and MgO, 9:1; solidification time, 1hr), all of heavy metal including aluminum were not detected. Therefore there are no problems for reuse or recycling of WTS which was solidified under the optimal solidification conditions found in the study.
        4,000원
        1940.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the previous study, three kinds of monomers and the functional monomer, acetoacetoxyethyl methacrylate (AAEM), which could improve the film property and cross-linkage, were polymerzied into acrylic resin copolymers (HSA-98-20, HSA-98-0, HSA-98+20) containing 80% solid content. In this study, the high-solid coatings(HSA-98-20C, HSA-98-0C, HSA-98+20C) were prepared by the curing reaction between acrylic resins containing 80% solid content and isocyanate at room temperature. Various properties were examined for the film coated with the prepared high-solid coatings. The introduction of AAEM in the coatings enhanced the abrasion resistance and solvent resistance of coatings, which indicated the possible use of high-solid coatings for top-coating materials of automobile. The curing times measured by viscoelastic measurement were 350, 264, and 212 min for HSA-98-20C, HSA-98-0C, and HSA-98+20C, respectively. This shows that the curing times become shorter with increasing Tg values.
        4,000원