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        검색결과 2,503

        1581.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Titanium dioxide particles are used as cosmetics, pigments, photocatalysts, adsorbents, catalytic supports, and sensors. The TiO2 particles were prepared by the precipitation in TTIP/Solvent mixtures and calcined at different temperatures. The resulting materials were characterized by XRD and SEM testing techniques. The TiO2 particles phase composition was determined by XRD ranging from amorphous to crystalline anatase and rutile largely proportional to the calcination temperature.
        4,000원
        1582.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ultraviolet curable coating solution was prepared with poly(ethylene glycol) acrylate oligomer and various mono and multi-functional acrylate monomers. The optical properties of UV cured coating layer on PET film with acrylate coating solution containing metal oxides, such as fumed silica and alumina, were also investigated to reduce light reflection on films. Poly(ethylene glycol) diacrylate which has 575 of average molecular weight was used as oligomer acrylate, and pentaerythritol triacrylate and dipentaerythritolpenta-/hexa acrylate were used as multi-functional acrylate monomers. Also, butyl acrylate was used to improve the adhesion as well as to reduce glass transition temperature to give a better flexability. 1-hydroxy cyclohexyl phenyl ketone was used as photoinitiator. We found out the metal oxides in acrylate coating solution showed a homogeneous dispersion from energy dispersive spectroscopy data. Transmittance and light reflection of coated PET film was measured with UV/vis spectrometer and gloss meter, respectively. When 1.00 g of both metal oxides was added into coating solution, the transmittance and the glossiness were reduced from 90% to 30% and from 190 GU to 35 GU, respectively. However, adding up to 1.00 g of the metal oxide into coating solution did not affect on the hardness of coating layer and adhesion between coated layer and PET film. Conclusively, we can control transmittance and light reflection of coated film by adjusting the amounts of metal oxide in coating solution.
        4,000원
        1583.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is manufacturing method and analysis of feasibility about collagen peptide from fish scale. This is processed by enzyme hydrolysis, isolating and refining etc. The results of analysis of nutritional composition showed protein content of collagen peptide. In the analysis of constitutive amino acids, the ratio of contents of hydroxyproline and glycine, the characteristics of collagen peptides appeared similar and the contents of glutamic acid and aspartic acid which are involved in protein metabolism. As a result of measurement of total polyphenol content and total flavonoid, it showed that collagen peptide had more contents generally, and the effect of bioactivity of pig-skin collagen peptide appeared higher although different kinds of scale collagen peptide showed a little DPPH radical scavenging ability, total antioxidant capacity by ABTS, ACE inhibitory.
        4,000원
        1584.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We carried out this experiment to observe an electrochemical properties for LB films of alkyl compounds by the cyclic voltammetry. Alkyl bromides was deposited by using the Langmuir- Blodgett method on the ITO glass. We measured to an electrochemical measurement by using cyclic voltammetry with a three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) in 0.5, 1.0, 1.5 and 2.0 N NaClO4 solution. A measuring range was reduced from initial potential to -1350 mV, continuously oxidized to 1650 mV. The scan rate were 100 mV/s. As a result, an electrochemical properties of the LB films of alkyl bromides appeared irreversible process caused by only the oxidation current from the cyclic voltammogram. The diffusivity(D) effect of LB films decreased with increasing of alkyl compounds amount.
        4,000원
        1585.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Metal(Zinc) soap and mixed metal(Zn/Ba) soap were synthesized with good structures and characterized by IR and H-NMR. The H-NMR spectrums of the synthesized soaps were in very good accordance with the structures proposed by earlier workers. The mixed metal soaps with various costabilizers(acid or metal content effect), which added in order to investigate the thermal stabilization effect at low and high temperature, were investigated the thermal stabilization effect. The temperature effect is relation to the metal content effect than acid effect. In case of mixed metal soap, the high thermal stabilization effect improved with increasing Barium content. As the Zinc content increase the low temperature thermal stabilization effect improved, but the high temperature thermal stabilization effect showed an opposite tendency.
        4,200원
        1586.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is a new method for prevent. The particulate scale. stero-microscope were used for the scale removal experiment to improve mineralogical characteristics and the reduction of scales in heat pipe. Generally, the scale in the heat pipe consists of calcium carbonate minerals, such as calcite and aragonite which are precipitated by the reaction of Ca and CO2 in the water. Copper alloy metal could eliminate the scale and prevent the production of scale in the heat pipe.
        4,000원
        1587.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cellulose triacetate (CTA) was prepared from cotton linter and pulps which contain various contents of α-cellulose. CTA which contains 2.8 of degree of substitution (DS) and 222 of degree of polymerization (DP) was obtained from V-81 pulp under the heterogeneous system. The DS was measured by the titration method, and the DP was obtained by measurement of viscosity. FT-IR spectometer (FT-IR 6300, JASCO) was used to analyze the chemical structure of raw materials and cellulose triacetate, and X-ray diffractometer (X-pert MPD PW3040, Philips) was used to confirm the crystal structure and to calculate the relative crystallinity index (RCI). As α-cellulose content in pulp increased, the acetylation yield increased. Besides with a kind of pulp, it contains insoluble residue which was mainly formed due to the formation of glucomannan triacetate and xylan diacetate during the esterification.
        4,000원
        1588.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have investigated the effects of polyols and NaCl on the rheological behaviours of surfactant mixtures. Sodium lauryl ether sulfate (SLES), cocamidopropyl betaine (CAPB), disodium cocoamphodiacetate (DSCA), cocamide DEA (CDEA) and lauroyl/myristoyl DEA (LMDE) were used as surfactants. The polyols added into the surfactant mixture were 1,3-butylene glycol, propylene glycol, glycerin, sorbitol, dipropylene glycol, PEG 1500 and PEG 400. The addition of amphoteric surfactant to SLES aqueous solution lead to increase the height of foam and the viscosity of the system. The addition of nonionic surfactant, LMDE or CDEA to the SLES aqueous solution increased the viscosity and the effect of LMDE was better than that of CDEA. The effect of adding polyols and NaCl into the surfactant mixture aqueous solution lead to increase or decrease the viscosity of the systems depending on the concentration of NaCl and the kinds of polyols. These results can be explained through the salting in or salting out of surfactant of the systems.
        4,000원
        1589.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Esterification reaction between succinic acid[SA] and 1,4-butanediol [BD was kinetically investigated in the presence of organic metal catalysts (alkyl-silver oxide(ASO),CAT 100E) at 150~190℃. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order kinetics with respect to the concentration of reactants and catalyst, respectively. The overall reaction order was 2nd. From the examination of relationship between apparent reaction rate constants and reciprocal absolute temperature, the activation energy has been calculate as 146.70 kJ/mol with ASO catalyst and 43.04 kJ/mol with CAT 100E catalyst.
        4,000원
        1590.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Water-in-Oil (W/O) emulsions are widely used in cosmetics. However, O/W (Oil-in-Water) emulsions are generally superior to W/O emulsions in terms of stability. In this study, we investigated the changes of viscosity, the size of emulsion droplets, and rheological properties of emulsions prepared using distearyldimonium chloride (DDC), magnesium aluminum silicate (MAS) and quaternium-18 hectorite (QH). In addition to the changes of the composition, we tested the condition of homogenization including rotation per minute of the mixer and the mixing time. The viscosity of emulsions with DDC and AMS were not changed with time and the stability of emulsions was stable during the storage time. However, the fluidity of emulsions were low due to the forming gel network in the emulsions. The gelling power of the emulsions with QH was rather weaker than that of the emulsions with DDC and MAS. The viscosity of emulsions with QH was gradually reduced and the phase separation of emulsions with high concentration of oil was observed throughout the storage time, however, the stability of emulsions with DDC, MAS and QH was excellent, the fluidity of emulsions was enhanced, and the viscosity of emulsions was sustained for a long time after setting of emulsions.
        4,000원
        1591.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the electrochemical properties for Langmuir-Blodgett (LB) films of functionalized polyimide. LB films of polyimide monolayer were deposited by the Langmuir-Blodgett method on the indium tin oxide(ITO) glass. The electrochemical properties measured by cyclic voltammetry with a three-electrode system(an Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode) at various concentrations(0.5, 1.0, and 1.5 N) of NaClO4 solution. The current of reduction and oxidation range was measured from 1650 mV to -1350 mV, continuously. The scan rates were 50, 100 and 150 mV/s, respectively. As a result, monolayer and multilayer LB films of polyimide are appeared on irreversible process caused by the oxidation current from the cyclic voltammogram.
        4,000원
        1592.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The esterification of palmitic acid in Jatropha Oil using 8wt% p-TSA catalyst was done at the 1:8 molar ratio of oil to methanol and 65℃. The conversion of palmitic acid appeared to be 95.3% in 60min. After that, the continuous transesterification of the oil using 0.5wt% KOH, 0.8wt% TMAH mixed catalyst[40vol% KOH(0.5wt%) + 60vol% TMAH(0.8wt%)] and 1.1wt% TMAH was conducted with the flow rates and the molar ratios at 65℃. The overall conversion of Jatropha Oil increased with the decrease of flow rate and showed 95.6% with 9ml/min of flow rate at the 1:8 molar ratio of oil to methanol and 65℃. But it showed 87% with 15ml/min of flow rate at the same conditions. The recovery of methanol(%) appeared to be 86% at the 1:8 molar ratio of oil to methanol, mixed catalyst and 65℃.
        4,000원
        1593.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of SO42- in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to 1050℃. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.
        4,000원
        1594.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Epoxy resin based encapsulants are widely used in semiconductor packaging applications. Epoxy resin based encapsulants are often subject to crack or delamination during the reliability test due to the thermal stress caused by high modulus nature of epoxy resins. Epoxy functional siloxanes are often added into epoxy resin to reduce the modulus so that the thermal stress can be reduced. Epoxy functional siloxanes, additives for reduced modulus, were synthesized and added into the curable epoxy resins. The modulus and the coefficient of thermal expansion (CTE) were also measured to investigate the thermal stress and to see whether the epoxy functional siloxane adversely affects the CTE or not. As a result, around 26% to 72% of thermal stress reduction was observed with no adverse effect on CTE.
        4,000원
        1595.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kinetic studies on the ligand substitution reactions of cyanocomplexes were performed in several micellar solutions. It showed the observed rate constants was found to be independent of the entering ligand concentration at high concentration of cyanopyridine and pyrazinecarboxylate. We could see also that in nonionic and anionic micellar solutions no influence of changes in the surfactant concentration on the observed rate constants was found. Taking into account the hydrophilic nature of the cobalt complex, the cobalt complex molecule was expected to be located in the aqueous phase of the micellar systems, where the reaction would take place. In cationic micellar solutions, a small increase in the observed rate constant was found when the cationic surfactant concentration increased. After reaching a maximum, the rate constant decreased on increasing surfactant concentration and subsequently it reached a plateau, where the observed rate constant was independent of changes in the surfactant concentration.
        4,000원
        1596.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Esterification reaction between succinic acid and 1,4-butanediol was kinetically investigated in the presence of monobutyl tinoxide catalysts at 150~190℃. The reaction rates measured by the amount of distilled water from the reaction vessel. The esterification reaction was carried out under the first order conditions with respect to the concentration of reactants, respectively. The overall reaction order was 2nd. The linear relationship was shown between apparent reaction rate constant and reciprocal absolute temperature. By the Arrhenius plot the activation energy have been calculated as 87.567 kJ/mol under monobutyl tinoxide catalyst and also apparent reaction rate constant, k' was found to obey first kinetics with respect to the concentration of catalyst.
        4,000원
        1597.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The authors have demonstrated white oraganic light-emitting diodes (WOLED) using 1,4-bis[2-(4'-diphenylaminobiphenyl-4-yl)vinyl]benzene as fluorescent blue emitter and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate as phosphorescent red emitter. The optimized WOLED using red host material as bis(2-methyl-8-quinolinato) -4-phenylphenolate exhibited proper color stability in comparison with the control device using 4,4'-N,N'-dicarbazole-biphenyl as red host. The white device showed a maximum luminance of 21100 cd/m2 at 14 V, luminous efficiency of 9.7 cd/A at 20 mA/cm2, and Commission Internationale de I'Eclairage (CIEx,y)coordinates of (0.32, 0.34) at 1000 cd/m2. The devices also exhibited the color shift with δCIEx,y coordinates of ± (0.01,0.01) from 100 to 20000 cd/m2.
        4,000원
        1598.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objection of this research is to conform of practicable possibility and recycling of producing junk after citrus fruits is processed. In the middle of practicable possibility, with verification of antibiosis that tactiling sensibility in a microorganism. With extracting d-limonene oil that have 70~90% a component of oil out of junk citrus peel, making certain the about 12000ppm(1.2%) concentration of it. By means of antibiosis property over the a pathogenic bacterium as well as a residence bacterium, considerating the limit of application against daily living supplies needs to antibiosis. Antibiosis effect of a stationing bacterium in the body permanently and by means of antibiosis verification of special bacteria Propionibacterium Acnes that causative skin trouble is selected, in based the antibiotic sencitivity test check up result of minimal inhibitory concentration(MIC).
        4,000원
        1599.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Natural grape extraction was extracted from grape component using diethyl ether as a solvent, and we tested various pharmaceutical and chemical characteristics of this extract. Characteristic experiments to use natural grape extract tested antimicrobial experiment using microbe in pharmaceutical material, and tested dye experiment using fiber in chemical material. From the result of characteristics experiment, some conclusions are obtained as follow. From the result of characteristics experiment, it obtained about 7.5%-grape extraction ratio as semi-solid state, and after dried in freezing from grape extract of semi-solid state, it obtained about 10%-grape extraction ratio as solid state of dark purple color. From result of antimicrobial experiment of grape extract, number of staphylococcus aureus (KCMC-01) and aspergillus niger (KCMC-02) in microbe decreased more and more according to time passage. This phenomenon showed that grape extract influences to antimicrobial effect. From the result of dye experiment of grape extract, it appeared in direction of dark purple color after dyed to use cotton and silk with fiber to control in pH 7.5. Specially the result which confirmed dye of fiber with optical electron microscope(OEM), we could know that it appears darker silk than cotton.
        4,000원
        1600.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the paste mixing of positive active materials which, affect the life cycle of batteries in Pb-Ca-Sn grids, and generation of 4BS in a curing process and considers the effects of these things on the initial charge characteristics and life cycle. In the results of the experiments applied in this study, it was possible to reduce the curing time in which the fine 4BS was formed by the mixing of the positive active materials of lead acid battery applied at high temperature compared to that of the existing coarse 4BS and that represented some improvements in the life cycle performance.
        4,000원