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        검색결과 676

        662.
        1999.02 KCI 등재 서비스 종료(열람 제한)
        Sorbents of calcined limestone and oyster particles having a diameter of about 0.63㎜ were exposed to simulated fuel gases containing 5000ppm H2S for temperatures ranging from 600 to 800℃ in a TGA (Thermalgravimetric analyzer). The reaction between CaO and H2S proceeds via an unreacted shrinking core mechanism. The sulfidation rate is likely to be controlled primarily by countercurrent diffusion through the product layer of calcium sulfde(CaS) formed. The kinetics of the sorption of H2S by CaO is sensitive to the reaction temperature and particle size, and the reaction rate of oyster was faster than the calcined limestone.
        665.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        A porous α-alumina tube of 2.5 ㎜ O.D. and 1.9 ㎜ I.D. was used as the support of an inorganic membrane. Macropores of the tube, about 150 nm in size, were plugged with silica formed by thermal decomposition of tetraethylorthosillcate at 600℃. The forced cross-flow CVD method that reactant was evacuated through the porous wall of the support was very effective in plugging macropores. The H_2 permeance of the prepared membrane was of the order of 10^-8 mol s^-1 m^-2 . Pa^-1, while the N_2 permeance was below 10^-11 mol. s^-1 . m^-2 . Pa^-1 at 600℃. This was comparable to that of silica-modified Vycor glass whose size was 4 nm.
        669.
        1996.10 KCI 등재 서비스 종료(열람 제한)
        The pure compound chloromethanes; methyl chloride, methylene chloride, chloroform and carbon tetrachloride were used as a model of chlorocarbon system with Cl/H ratio to investigate thermal stability and hydrodechlorination process of carbon tetrachloride under excess hydrogen atmosphere. The parent thermal stability on basis of temperature required for 99% destruction at 1 second reaction time was evaluated as 875℃ for CH3Cl, 780℃ for CH2Cl2, 675℃ for CHCl3, and 635℃ for CCl4. Chloroform was thermally less stable than CCl4, at fairly low temperatures (<570℃). The decomposition of CCl4, became more sensitive to increasing temperature, and CCl4 was degraded easier than CHCl3 at above 570℃. The number and quantity of chlorinated products decreases with increasing temperature for the product distribution of CCl4 decomposition reaction system. Formation of non-chlorinated hydrocarbons such as CH4, C2H4 and C2H6 increased as the temperature rise and particularly small amount of methyl chloride was observed above 850℃ in CCl4/H2 reaction system. The less chlorinated products are more stable, with methyl chloride the most stable chlorocarbon in this reaction system.
        670.
        1996.06 KCI 등재 서비스 종료(열람 제한)
        Granular sludge formation and it`s activity change are the most important factors in achieving successful start-up and operation of UASB reactor. Nevertheless, the detailed mechanism is still unknown. On the basic of the experiments in laboratory-scale UASB reactor, the effect of hydrogen partial pressure on sludge granulation was evaluated. Size distribution method and specific metabolic activity of the sludge with the operation time were used as a means for estimating the degree of the sludge granulation. At the constant hydrogen loading, the granulation increased as starvation periods in hydrogen supply increased, resulting in high organic removal efficiency. It was evidient that hydrogen play very important role in granulation and sludge granulation was achieved through mutual symbiosis between hydrogen utilizing bacteria and hydrogen producing bacteria under the hydrogen deficient conditions.
        672.
        1995.08 KCI 등재 서비스 종료(열람 제한)
        This study was investigated with denitrification of wastewater containing nitrate using upflow sludge blanket process. Contents of this study were the NO_3^- -N removal efficiency by various hydrogen donor addition, determination of optimum COD/NO_3^- -N ratio and characteristics of granular sludge.
        675.
        1991.02 KCI 등재 서비스 종료(열람 제한)
        다량의 대기오염물(SO2, HF)이 배출되고 있는 공업단지 주변에서 재배되고 있는 수도의 생육에 이들 대기오염물이 미치는 영향을 구명하기 위하여 수도의 각종 형질, 수량, 대기중의 오염물 농도, 엽내유황 및 불소함량과 엽피해율을 조사하여 시험한 결과는 다음과 같다. 1. 엽내유황함량과 대기중 아황산가스 농도간에는 높은 정의 상관이 인정되었다. 2. 엽피해율 조사치는 대기오염에 의한 수량감소의 가장 중요한 지표로 이용 할 수 있다. 3. 본 조사지역에서는 아황산가스보다 불화수소의 배출량이 적지만 엽피해의 발생에는 불소의 관련성이 아황산가스보다 높았다. 4 수량형질의 수량에 대한 기여정도는 주당수수가 제일 컸으며, 주당수수는 엽내 불소함량과 깊은 관련성이 인정되었다. 5. 엽내 유황함량은 수량 및 수량형질과 상관성이 인정되지 않았다.
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