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        검색결과 3

        1.
        2004.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An aqueous solution of a commercial liquid synthetic detergent for kitchen use was photodecomposed in the presence of titanium dioxides powder under an atmosphere of air at room temperature. Titanium dioxides were prepared by sol-gel method from titanium iso-propoxide at different R ratio(H2O/titanium iso-propoxide) and calcined at 500℃. All titanium dioxides were characterized by XRD, BET surface area analyzer and UV-VIS spectrometer. The surface area of titanium dioxides prepared at R ratio=6 appeared higher volume about 20% than commercial TiO2 catalysts. XRD patterns of titania particles were observed mixing phase together with rutile and anatase type. Titanium dioxides prepared by sol-gel method show higher activity about 6% than commercial TiO2 catalysts on the photocatalytic degradation of a commercial liquid synthetic detergent for kitchen. The concentration of the detergent decreased to about 90% of its initial value at illumination times of 2 hour. Illumination for 30 minutes decreased the concentration of oxygen to about one-fifth of the initial value.
        4,000원
        2.
        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
        3.
        1985.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        AOM and lamp tests were carried out with soybean, corn, palm oil and beef tallow without the addition of antioxidant. The evaluation of rancidity for the stability was determined by changes of peroxide value and acid value, and the correlation between the stability and the composition of fats and oils was examined. The results obtained were as follows. 1. In the AOM test, POV began to rise in the order of corn oil, soybean oil, beef tallow and palm oil. However, the time required to reach POV 100 in beef tallow was faster than other fats and oils. It was found that there was a good correlation between POV and content of tocophrol. 2. In the lamp test by light of main wavelength 253.7nm, beef tallow was stabler than soybean and corn oil. It was because the absorption of light into beef tallow was much smaller than others, since beef tallow was fats. Palm oil was very stable in all the samples during AOM and lamp test.
        4,000원