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정흥채,김정회 한국산업미생물학회 1992 한국미생물·생명공학회지 Vol.20 No.4
동물세포 배양기에서 silicone tube를 oxygenator로 이용하여 산소전달 정도를 조사하였다. Silicone tube를 이용할 때 표면통기에 비해 산소전달 상수 k_La는 약 30배 이상 증가하였다. 통기속도와 교반속도가 증가할수록 k_La값도 증가하지만 교반속도가 휠씬 효과적이었고, 물질전달에 관한 무차원 상수 tubing Sherwood number(Sh)와 유체 흐름에 관한 상수 impeller Reynolds number(Re)는 log-log 좌표에서 직선관계가 있었고 기울기는 tube 길이에 관계없이 0.26이었다. Tube 길이는 2m가 적당하였고 impeller는 pitched blade type이 효과적이었다. 5% serum이 첨가된 medium에서는 k_La가 40%로 감소하였다. HepG2를 이용한 실제 동물세포 배양에서는 전형적인 세포농도인 4∼6×10^6 cells/㎖를 얻을 수 있었다. An enhancement of the oxygen transfer rate in a 1ℓ bioreactor for mammalian cell culture by using a silicone rubber tubing as an oxygenator was investigated. When the silicone membrane was used to supply oxygen to the culture broth, the oxygen transfer coefficients (k_La) measured in deionized-distilled water were markedly increased. Effect of surface aeration without the tubing aeration was very low under 1.0 hr^-1 of k_La. The enhancing effects of agitation rates on k_La were much more effective than those of aeration rates. The increase of k_La with increasing tube length was observed as a result of the large surface area for oxygen supply. However, 2m of the tube length was adequate for a 1ℓ vessel. The larger blade type of impeller was effective to enhance the k_La values because of its high mixing intensity. In culture medium supplemented with 5% serum, k_La values were reduced to approximately 40% probably due to the viscosity. We also obtained the normal cell concentration of 5×10^6 cells/㎖ of HepG2 on microcarriers, which could be achieved in a typical bioreactor for animal cell culture.
정흥채(Chung Heungchai),엄기영(Eum Kiyoung),김석원(Kim Sukwon),서정원(Seo Jungwon),신종한(Shin Jonghan) 한국철도학회 2002 한국철도학회 학술발표대회논문집 Vol.- No.-
A field of test and evaluation plays an important role in railway system in the safety and reliability aspects. In this paper, test and evaluation items for various railway systems i.e., conventional railway system, tilting system, and high speed railway system, were compared to analyze characteristics of the systems.