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        검색결과 113

        42.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Four activated carbons were produced by two-stage process as followings; semi-carbonization of indigenous biomass waste, i.e. cotton stalks, followed by chemical activation with KOH under various activation temperatures and chemical ratios of KOH to semi-carbonized cotton stalks (CCS). The surface area, total pore volume and average pore diameter were evaluated by N2-adsorption at 77 K. The surface morphology and oxygen functional groups were determined by SEM and FTIR, respectively. Batch equilibrium and kinetic studies were carried out by using a basic dye, methylene blue as a probe molecule to evaluate the adsorption capacity and mechanism over the produced carbons. The obtained activated carbon (CCS-1K800) exhibited highly microporous structure with high surface area of 950 m2/g, total pore volume of 0.423 cm3/g and average pore diameter of 17.8 a. The isotherm data fitted well to the Langmuir isotherm with monolayer adsorption capacity of 222 mg/g for CCS-1K800. The kinetic data obtained at different concentrations were analyzed using a pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The pseudo-second-order model fitted better for kinetic removal of MB dye. The results indicate that such laboratory carbons could be employed as low cost alternative to commercial carbons in wastewater treatment.
        4,200원
        48.
        2008.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this work is to study the feasibility of the preparation of the activated carbon (AC) from coconut tree flowers using high temperature fluidized bed reactor (HTFBR). The activating agent used in this work is steam. The reactor was operated at various activation temperature (650, 700, 750, 800 and 850℃) and activation time (30, 60, 120 and 240 min) for the production of AC from coconut tree flowers. Effect of activation time and activation temperature on the quality of the AC preparation was observed. Prepared AC was characterized in-terms of iodine number, methylene blue number, methyl violet number, ethylene glycol mono ethyl ether (EGME) surface area and SEM photographs. The best quality of AC from coconut tree flowers (CFC) was obtained at an activation temperature and time of 850℃ and 1 hr restectively. The effectiveness of carbon prepared from coconut tree flowers in adsorbing crystal violet from aqueous solution has been studied as a function of agitation time, carbon dosage, and pH. The adsorption of crystal violet onto AC followed second order kinetic model. Adsorption data were modeled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacity qm was 277.78 mg/g., equilibrium time was found to be 180 min. This adsorbent from coconut tree flowers was found to be effective for the removal of CV dye.
        4,000원
        52.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The international cooperation project CIBER (Cosmic Infrared Background ExpeRiment) is a rocket-borne instrument, of which the scientific goal is to measure the cosmic near-infrared extra-galactic background to search for signatures of primordial galaxy formation. CIBER consists of a wide-field two-color camera, a low-resolution absolute spectrometer, and a high-resolution narrow-band imaging spectrometer. Currently, all the subsystems have been built, and the integration, testing, and calibration of the CIBER system are on process for the scheduled launch in June 2008.
        4,000원
        57.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        생장조절물질과 광도가 국화 경정배양에 미치는 영향 을 조사하였다. 다신초(multiple shoots) 형성은 국화 경 정을 MS배지에 kinetin 2.0mg · L-1와 NAA 0.2mg · L-1 첨가된 배지에 배양하였을 때 촉진되었으며, 형성된 다 신초는 MS배지에 kinetin 2.0mg · L-1와 NAA 0.02 mg · L-1 첨가된 배지에 배양하였을 때 생육이 촉진되었 다. 한편, 국화 경정을 NAA 0.2mg·L-1와 BA 1.0mg · L- 1가 첨가된 배지에 배양하였을 경우에는 절편체당 신초 형성 수가 6.9개로 가장 많았으나 형성된 신초의 대부분 이 유리질화 되었다. 기내에서 국화묘의 생장은 광도 100 μmol · m-2 · s-1 PPFD에서 신초의 길이와 엽록소 함량이 가장 높았다.
        4,000원
        58.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The application of membrane bioreactors for the depuration of wastewater coming from the washing of mineral oil storage tanks is described. Microfiltration hollow-fibre membranes were used in the submerged configuration. Filtration tests were carried out with a biomass concentration of about 15 g/L in order to assess the critical flux of the hollow fibre membrane used. Then particular care was taken in carrying out the performance runs in the sub-critical flux region. The reactor performance was very high, with removal efficiencies ranging between 93% and 97% also when the concentration of hydrocarbon was very high. Some kinetic parameters for the COD and the hydrocarbon removal were estimated.
        4,000원
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