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        검색결과 18

        1.
        2004.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adsorption of heavy metals in the waste water carried out on the various domestic clays and waste pottery. The effect of parameters such as pH, temperature, adsorption time and coexisting cations on the adsorption ability and characteristics were investigated to find out whether the clays could be used as adsorbents. Adsorption equilibrium was reached within 20 minutes on all the clays. The optimum pH was found to be above 5. When other cations such as Cu(II) or Zn(II) coexisted with Pb(II), the adsorption amount of Pb(II) decreased because of competing adsorption.
        4,000원
        2.
        2004.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to increase of using quantity, people interested in the environmental influence by synthetic detergent. The main visible form when synthetic detergent dissolved in water is generating foams. This foam makes coating over water surface and prevents oxygen penetrating in water and make water more polluted with that result. To analyze, components and origins of the foam, and to make clear its environmental influence in this study. The analyzing objects are introducing water of sewage treatment plant from the a tributary to the Han River. After analysis, reached the conclusion like below, Analyzing foams and introducing water by sublation method, average return rate of standard LAS (1.0ppm) is 90%. LAS contents of foams analyzed by UV photometric method and HPLC method are 35.0ppm and 44.5ppm each, and AOS contents of foams analyzed by the same method are 0.6ppm and 0.4ppm each. We can find out by this study's analyzing results that the main components of foams are anion surfactant, it's content and in case of capric acid linoleic acid, it's contents.
        4,000원
        3.
        2002.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two PU flame-retardant coatings, 2,3-DBPO/N-l00 (DBPON) and 2,3-DBPO/IL (DBPOI), were prepared by curing 2,3-dibromo modified polyester (2,3-DBPO) with isocyanate curing agent Desmodur N-l00 (or Desmodur IL) at room temperature. The physical properties and flame-retardancy of the two coatings were tested and compared. As a result, the pot-life, yellowness index, lightness index difference, 60˚ specular gloss, cross-hatch adhesion, viscosity, and accelerated weathering resistance of DBPON were better than those of DBPOI; the fineness of grind of the two coatings were the same; and the drying time, hardness, and abrasion resistance of DBPOI were better than those of DBPON. The flame retardancy of the flame-retardant coatings increased with the content of the flame retarding component, 2,3-dibromopropanoic acid (2,3-DBP); and the LOI values of the two coatings were in a range of 27~29% when the content of 2,3-DBP was 30wt%.
        4,000원
        5.
        2000.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Drug delivery system(DDS) applied to various fields, such as medicine, cosmetics, agriculture and necessities of life. Among these application fields, DDS is often used as the method of drug dosage into the epidermic skin. We investigated characters of transdermal therapeutic system(TTS) and the skin permeability of that with applying DDS. Chitosan was selected as material of TTS. We investigated the permeation of chitosan ointment containing drug in rat skin using horizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug such as riboflavin in vitro. We used glycerin, PEG 600 and oleic acid as enhancers. Since dermis has more content water(hydration) than the stratum corneum, skin permeation rate at steady state was highly influenced when glycerin was used in water-soluble drug. The permeation rate of content enhancer and drug was found to be faster than that of content water-soluble drug only. These results showed that skin permeation rate of drug across the composite was manly dependent on the property of ointment base and drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate.
        4,000원
        6.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In spite of various applications of chitin derivatives from waste marine sources, commercial use of chitin has been limited due to resistance to chemicals and the absense of proper solvents. We prepared chitin through decalcification, bleaching and deproteination from protunus trituberculatus shells by the application of Hackman's method. Structural and chemical properties of chitin were investigated to have proper specific surface area and particle size by IR, BET and PSA. The amount of absorbed water of chitin reached equilibrium by stirring about 15 minutes. The amount of absored water of the prepared chitin were large than the commercial chitin. When prepared chitin tested on dyeing wastewater, they showed better treatment efficiency in COD, suspended solid, and color tests than the commercial chitin. The adsorption capacity increased with decreasing particle size for the prepared chitin. Treatment efficiency for color was increased as the sitirring rate increased. Results show the possibility of the prepared chitin from waste marine sources as a treatment system for dyeing wastewater.
        4,000원
        7.
        1998.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chitin/chitosan be known as biodegradable natural polymer. However, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. Therefore, we was studied that chitin was prepared by the application of Hackman's method from Protunus trituberculatus shells. And another viscosity chitosan were prepared from chitin which were deacetylated under various concentration of alkali, reaction time and temperature by the application of Mima's method. And crosslinked chitin/chitosan was preparaed from chitin/chitosan with crosslink agent followed by crosslinkage. The major parameters for chitosan manufacturing methods were found to be concentration of alkali solution, reaction time and temperature etc. The effects of these parameters on chitin, another viscosity(molecular weight) chitosan and crosslinked chitin/chitosan were investigated by various analysis apparatus.
        4,200원
        8.
        1996.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        EMA-co-DAMA were synthesized from 2-diethylaminoethyl metacrylate and ethylhexyl metacrylate in acrylmonomer. To facilitate water emulsification, acrylic copolymer was cationized by acetic acid to produce acetated acrylic copolymer. The structures of the synthesized copolymer and acetated copolymers were confirmed by IR, NMR, and molecular weight was measure by GPC, and C.H.N elemental analysis. Acetated acrylic copolymers were perfectly emulsified in water and showed increased emulsion stability. Polymer dispersion for cement modifier[(PDCM-PED) water proof agent of cement for concrete in building construction] was prepared by blending of the guaternized acrylic copolymer syndisized above, sodium silicate, sodium gluconate and oleic acid emulsion. The result with prepared polymer dispersion of cement modifier was examined, and it was found that excellent waterprooffing effect ; Water permeability ratio is 0.50 under the water pressure of 100g/cm2 and 0.60 under 3kg/cm2, and water absorption ratio is 0.42~0.50 and 1.0~1.02 compressive strength ratio at mixed of water/PDCM-PED is 50 times.
        4,300원
        9.
        1996.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fluorenylidene chalcone derivatives were synthesized by condensation. The structure of these compounds were ascertained by means of UV, melting point, IR and 1H-NMR spectra. The nucleophilic addition reaction kinetics of Thioglycolic acid to fluorenylidene chalcone was investigate by UV in 20% dioxane-H2O at 25℃. The rate equation which were applied over a wide pH1.0~13.0 range. On the basis of general base catalysis and confirmation of addition reaction product, the nucleophilic addtion reaction kinetics of thioglycolic acid to fluorenylidene chalcone were measured by the pH change. From the result of the above caption, a plausible nucleophilic addition reaction mechanism of thioglycolic acid to fluorenylidene chalcone was proposed. These compounds may be used as the starting materials for the preparation of the engineering plastics or the germicide.
        4,000원
        10.
        1993.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The hydrolysis reaction kinetics of 2-thienyl chalcone derivatives [II]~[V] was investigated by ultraviolet spectrophotometery in 20% dioxane-H2O at 25℃ and the structure of these compounds were ascertained by means of ultraviolet, infrared and NMR spectra. The rate equations which were applied over a wide pH range(pH 1.0~13.0) were obtained. The substituent effects on 2-thienyl chalcone derivatives[II]~[V] were studied, and the hydrolysis were facilitated by electron attracting groups. On the basis of the rate equation, substitutent effect and final product, the plausible hydrolysis reaction mechanism was proposed : At pH 1.0~9.0, not relevant to the hydrogen ion concentration, neutral H2O molecule competitvely attacked on the double bond. By contraries, above pH 9.0, it was proportional to concentration of hydroxide ion.
        4,000원
        11.
        1993.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, p-CH3 m-CH3, p-OCH3) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-H2O at 25℃. A rate equation which can be applied over wide pH range(pH 1.0~13.0) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH 1.0~9.0 was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.
        4,000원
        12.
        1993.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The hydrolysis kinetics of 2-furyl chalcone derivatives [I]~[V] was investigated by ultraviolet spectrophotometery in 30% dioxane-H2O at 25℃ and the structure of these compounds were ascertained by means of ultraviolet, infrared and NMR spectra. The rate equations which were applied over a wide pH range(pH 1.0~12.0) were obtained. The substituent effects on 2-furyl chalcone derivatives [I]~[V] were studied, and the hydrolysis were facilitated by the electron attrecting groups. On the basis of the rate equation, substituent effect, general base effect and final product. the plausible hydrolysis mechaism was proposed: Below pH 4.0, it was only proportional to concentration of hydronium ion, at pH 4.0~9.0, neutral H2O molecule competitively attacked on the double bond. By contrast, above pH 9.0, it was proportional to concentration of hydroxide ion.
        4,000원
        13.
        1991.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The kinetics of the addition of 1-benzylindole-3-(p-substituted) acetophenone derivatives was investigated by ultraviolet spectrophotometery in 30% dioxane -H2O at 25℃. A rate equation which can be applied over wide pH range was obtained. The Substituent effects on 1-benzylindole-3-(p-substituted) acetophenone derivatives were studied, and addition were facilitated by electron attracting groups. On the base of the rate equation, substituent effect, and general base effect the plausible addition mechanism was proposed : Below pH 3.0, only neutral thiourea molecule was added to the carbon-carbon double bond, and in the range of pH 0.0~14.0, netural thiourea molecule and thiourea anion competitively attacted the double bond. By contrast, above pH 10.0, the reaction was dependent upon only the addition of thiourea anion.
        4,000원
        14.
        1991.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The kinetic of hydrolysis for cinnamylidene aniline derivatives has been investigated by ultraviolet spectrophotometry in 20% (v/v) dioxane - H2O at 25℃. A rate equation which can be applied over wide pH range was obtained. The substituent effects on cinnamylidene aniline derivatives were studied and the hydrolysis was facilitated by electron attracting group. Final products of the hydrolysis were cinnamaldehyde and aniline. From the rate equation, substituent effect and final products, the hydrolysis of cinnamylidene aniline derivatives was initiated by the neutral molecule of H2O which does not dissociate at below pH 9.0~12.0, but proceeded by the hydrogen ion at above pH 5.0~9.0.
        4,000원
        15.
        1990.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Kinetics of the addition of benzalacetophenone derivatives was investigated by ultraviolet spectrophotometery in 5% dioxane H2O at 50℃. A rate equation was obtained in wide range of pH. The substituent effects on benzalacetophenone derivatives were studied, and addition were facilitated by electron attracting groups. The final product was benzalacetophenone-β-thioglycolic acid synthesized by the addition of thioglycolic acid to benzalacetophenone. On the base of the rate equation, substituent effect, general base effect and final product, the plausible addition mechanism was proposed: Below pH 9.0, only neutral thioglycolic acid molecule was added to the carbon-carbon double bond, and in the range of pH 9.0~11.0, neutral thioglycolic acid molecule and thioglycolic acid anion competitively attacted the double bond. By contrast, above pH 11.0, the reaction was dependent upon only the addition of thioglycolic acid anion.
        4,000원
        16.
        1989.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Kinetics of the Hydrolysis of benzalacetophenone derivatives has been investigated by ultraviolet spectrophotometry in 5% dioxane - H2O at 50℃. A rate equation which can be applied over wide pH range was obtained. The substituent effect on the hydrolysis of benzalacetophenone derivatives were facilitated by electron attracting groups. Based on the rate equation, substituent effect, general base effect, activation parameters and final product, the hydrolysis of benzalacetophenone derivatives seems to be initiated by the netural molecule of H2O which does not dissociate at below pH 9.0 but proceeded by the hydroxide ion at above pH 11.0. In the range of pH 9.0~11.0 these two reactions occur competitively.
        4,000원
        17.
        1989.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The rate constants of the hydrolysis of cinnamanilide derivatives were determined UV spectrometry in H2SO4 (5~20N), NaOH(5~11N) at 50~110℃ and rate equation could be applied over a strong acid and strong base were obtained. Final product of the hydrolysis was a cinnamic acid. The σ values obtained from the slope of linear plots of log kabs vs. Hammet tΣ constants were slightly negatives, Substituents on cinnamanilide showed a relatively small effect, with hydrolysis facilitated be electron donating group. Activation energy(Ea)was also calculated for the hydrolysis of the cinnamanilide. From this reaction rate equation, substituent effect and experimental of rate constants, that the hydrolysis of cinnamanillde was Initiated by the netural molecule of H2O which do not dissociate at strong acid, and proceeded by hydroxide ion at strong base.
        4,000원
        18.
        1987.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Linear alkylbenzene sulfonate (LAS) from the mixture of anionic and nonionic detergents (containing amide type and alkylphenoxy polyethanol type) is identified by Fourier transform infrared spectrometer, separated using physical properties (solubility) and determined by nuclear magnetic resonance spectroscopy
        3,000원