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침전법으로 제조한 Ni/SiO2 촉매에서 규산니켈의 생성에 따른 촉매의 특성변화
정종식,문상흡,서동진,임태훈 한국화학공학회 1989 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.27 No.5
실리카 담체가 분산된 질산니헬의 수용액 중에 암모니아수 또는 탄산소다 등의 알칼리 침전제를 주입하여 니켈염을 침전시키면서 니켈/실리카 촉매를 제조할 때에 침전조건에 따른 촉매의 특성변화를 주로 X-선 회절법으로 관찰하였다. 제조된 촉매의 특성은 침전과정에서 촉매표면에 생성된 규산니켈의 양에 따라서 크게 변화한다. 즉, 촉매표면의 규산니켈이 증가하면 촉매의 총 표면적은 증가하고 니켈입자의 크기, 환원도 등은 감소하며 담체표면이 불규칙하게 되고 촉매의 기공크기도 감소한다. 한편, 이 규산니켈은 침전용액의 온도가 높고 침전제의 주입속도가 느린 경우에, 그리고 암모니아수 보다는 탄산소다를 침전제로 사용하는 경우에 그 생성량이 증가하는 것으로 밝혀졌다. 탄산소다를 침전제로 사용한 경우에는 니켈염을 빨리 침전시킨 후에 이어서 용액의 pH를 높게 유지하고 장시간 숙성처리했을 때에 규산니켈의 생성량이 크게 증가하지만, 반대로 암모니아수를 침전제로 사용한 경우에는 이러한 숙성처리없이 침전제를 서서히 첨가하여 니켈염을 천천히 침전시키는 방법이 규산니켈의 생성량을 높이는 데에 효과적이다. 규산니켈의 생성량이 증가하면 불포화지방산의 수소화반응에 대한 촉매의 활성이 급격히 떨어지는 데, 이것은 규산니켈의 생성에 의하여 촉매의 기공크기가 작아지고 따라서 반응물이 촉매기공 내로 확산해 들어가기가 힘들어지기 때문으로 판단된다. Ni/kieselguhr catalysts have been prepared by precipitation of nickel nitrate with either ammonium hydroxide or sodium carbonate in a solution where kieselguhr particles are suspended. Changes in the catalyst properties with the preparation conditions have been studied primarily by observing the X-ray diffraction patterns of the sample catalysts. The amount of nickel silicate formed on the catalyst surface during the precipitation step is closely related to the properties of the catalysts. That is, formation of nickel silicate on the catalyst increases the total surface area of the catalysts, and reduces the nickel particle size as well as its reducibility. Nickel silicate also makes the silica surface rough, thus reducing the pore opening of the support. Nickel silicate is enhanced on the catalyst when the alkaline precipitant, preferably sodium carbonate than ammonium hydroxide, is injected slowly into the nickel nitrate solution which is maintained at high temperature. Aging of the precipitation solution at high pH after fast precipitation enhances the formation of nickel silicate on the catalyst, particularly when sodium carbonate is used as a precipitant. However, when ammonium hydroxide is used as a precipitant,slow precipitation without aging is more effective for the nickel silicate formation than fast precipitation followed by aging. The hydrogenation rates of unsaturated fatty acid on the nickel catalysts decrease significantly when nickel silicate is formed on the catalyst to certain extents. This seems to result from retarded diffusion of the large reactant molecules into the catalyst pores, whose opening size has been reduced by the nickel silicate formation.
鄭然植,徐允換 경북대학교 1986 社會科學 Vol.5 No.-
The purpose of this paper is to search for the meaning of the mediator of plural-social values today by studying Hobhouse's basic conception, that is, the idea of harmony in his thought. Historically, as ideals the idea of harmony has been the subject of political philosophy. Hobhouse derived it from F.H. Bradley's concept of "the Absolute". In this point he believed reality to be a harmonious system. Also, he was affected by the spirit of Hegelianism. This paper traced the idea of harmony through his theory of development and the role ascribed to reason in his system. Therefore, he emphasized on the inner harmony of feeling and effort and postulated co-operation as the idea of harmonious developnent in the organic view of society. This idea of harmony is related to the social values in the development of personality and the realization of the common good as the whole. In conclusion, the idea of harmony represents the reconciliation of the ideas of whole and part, of society and individualism and their legitimate claims.And he interpreted liberalism as the doctrine of social reform to realize the individual freedom. So, he was estimated highly in the history of liberal thought as a new liberal movement.
호흡기 감염증 환자에 대한 Cefoperazone의 임상 효과
서환조,신완식,강문원,이정희,정희영,이학중,박성수,이홍순 대한감염학회 1984 감염 Vol.16 No.1
Cefoperazone is a new piperazine cephalosporin derivative which has a broad antibacterial activity against aerobic & anaerobic gram-negative cocci and bacilli, including P. aeruginosa. A total of 75 patients with a variety of respiratory tract infections were treated with Cefoperazone. The drug was administered intravenously in dose of 4∼6g per day for 7 to 14 days. The clinical response was satisfactory in 46 (70.0%) of 65 patients with pneumonia,5 (70.1%) of 7 with bronchiectasis complicated by infections, 2 (50%) of 4 with infections secondary to chronic respiratory disease, 1 with pyothorax, 1 with severe chronic bronchitis. Overall, Cefoperazone was effective in 54 (72.0%) of all patients treated. Adverse effects-mainly fever, rash-occurred in only 4.0%, and abnormal results of laboratory test-mainly elevation of hepatic enzyme levels-occurred in 4.0% of all patients treated. But it is doubtful whether these adverse effects are related to Cefoperazone or not.
이중섭(Chung-Seub Yi),신재호(Jae-Ho Shin),이해종(Hae-Jong Lee),서정세(Jeong-Se Suh),정한식(Han-Shik Chung),정효민(Hyo-Min Jeong) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
This study is analysis on the heat transfer of exhaust gas into the muffler at passenger car. Numerical analysis with Computational fluid Dynamics(CFD)was carried out to investigate exhaust gas flow. The STAR-CD S/W used for the three dimensional steady state CFD ananlysis in a muffler. The Navier-Stokes Equation is solved with the SIMPLE method in a general cartesian coordinates system. Result of numerical simulation; Inlet and outlet temperature shown about ΔT=239K, 216K, 202K at in the muffler. Heat transfer was progressed quickly by atmospheric temperature of muffler external at in the near wall.