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Effective extraction of elastase from Bacillus sp. fermentation broth using aqueous two-phase system 总被引：1，自引：0，他引：1
INTRODUCTION Aqueous two-phase system (ATPS) is widely used in biochemistry and biotechnology for purifica- tion of proteins (Diamond and Hsu, 1992; Balasubramaniam et al., 2003), enzymes (Pan et al., 2001; Bim and Franco, 2000), amino acids (Li et al., 2002), antibiotics (Yang et al., 1994; Guan et al., 1994), nucleic acids (Ohlsson et al., 1978; Kimura, 2000), aroma compounds (Marco et al., 2000) and lactic acid (Planas et al., 1998). ATPS is mainly composed of two-incompatible p… 相似文献
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双水相萃取技术是一项新的分离技术,因其具有独有的特点,应用越来越广泛,在生物技术领域中的应用最为普遍。主要介绍了双水相的种类及应用特点,展示了近三年来双水相萃取技术在生物技术中的应用,最后探讨了双水相萃取技术的应用前景。 相似文献
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管道输运工程中经常遇到两相流问题,因此需要预测对流体施加的压力大小以指导运输。拟对圆直管道分层两相流-层流模型做研究,用解析方法计算出圆管任一截面处流体的速度分布,并验证两层流体交界面处的摩擦力与其平均速度差值呈近似线性关系的结论。以此为基础,可以通过计算截面速度分布得到流体与管壁的摩擦力,通过输运流体所需达到的速度得到分界面处摩擦力,最终反推出运输流体所需要施加的压力差大小。 相似文献
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基于双相各向同性介质模型,推导了双相各向同性介质中波动方程的有限差分格式,并对其进行了数值模拟.结果表明,弹性波在双相各向同性介质中传播时除了存在常规的快纵波(qP1)和横波以外,还存在慢纵波(qP2),并且慢纵波的速度明显小于快纵波. 相似文献
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描述了基于J2EE架构的事务管理在项目中的应用,研究了J2EE项目中使用事务的方法,分布式环境中的事务处理及两阶段提交方法实现,分析总结了事务应用中应遵循的习惯. 相似文献
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结合建筑系高年级学生的专业特点和心理特点,在教学实践中提出以＂总体认识＂和＂深化理解＂为两个阶段、以＂问题-讲解-评析-小结＂为四个环节的＂双阶段四步课堂教学法＂,形成＂教＂与＂学＂的良好互动,激发学生发现问题、分析问题、解决问题的欲望,以促进学生综合能力的提升。 相似文献
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It is well known that the most prominent characteristic of emergency systems is the limit of time. A scheme must be made in
much shorter time, and the retrieval vehicle should be able to reach the emergency site in the earliest time according to
the proposed scheme so that the emergency event is dealt with as early as possible. This paper deals with multi-depot problems
in two cases: (1) When the duration or time needed by the retrieval vehicle arriving at the emergency site from each depot
is a non-negative real number, a single-objective (or min-max) and a two-phase problems on the earliest-emergency-activity-start-time
(EEAST) are considered. (2) When the duration is regarded as an interval number, we consider the problem of finding an opting
scheme meeting a given deadlinet with maximum possibility (or truth value). 相似文献
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ＩＮＴＲＯＤＵＣＴＩＯＮＭａｎｙｅｘｐｅｒｉｍｅｎｔａｌａｎｄｎｕｍｅｒｉｃａｌｓｔｕｄｉｅｓｈａｖｅｂｅｅｎｃｏｍｐｌｅｔｅｄｔｏｉｎｖｅｓｔｉｇａｔｅｔｈｅｐａｒｔｉｃｌｅｍｏｔｉｏｎｉｎｔｕｒｂｕｌｅｎｃｅ .Ｐｒｅｖｉｏｕｓｆｌｕｉｄｄｙｎａｍｉｃｓｓｔｕｄｉｅｓｗｅｒｅｃｏｍｍｏｎｌｙｂａｓｅｄｏｎｔｉｍｅ ａｖｅｒａｇｅｄＲｅｙｎｏｌｄｓｅｑｕａｔｉｏｎｓ,ｓｕｃｈａｓｔｈｅｔｗｏ ｅｑｕａｔｉｏｎｍｏｄｅｌ.Ｊｕｓｔｌｉｋｅｔｈｅｃａｒｒｉｅｒｇａｓｐｈａｓｅ,ｔｈｅｐａｒｔｉ ｃｌｅｐｈ… 相似文献
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在电站锅炉燃烧器的研究中，对于燃烧器中气体．颗粒两相流动的流场数据的测量，通常以采用粒子动态分析仪（Particle Dynamic Analyzer，简称PDA）为较好选择。本文采用三维粒子动态分析仪（3D-PDA）对燃烧器内气固两相流动的冷态流场进行了实验测量，其中在搭建实验台、选择固相粒子、布置测量光路和考虑相似性原则等方面做了一些有益的探索工作。 相似文献
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Sedimentation tanks and clarifiers play a significant role in an active sludge system, and the efficiency of the whole system is closely related with the design and operation of the sedimentation tanks. This paper focuses on the sludge concentration in each cross-section of the sedimentation tank. We measured the sludge concentration to explore its distribution inside the tank, carried in-situ tests to research the fluid pattern and real operational rules of the sedimentation tank. We also used the computational fluid dynamics (CFD) software, PHOENICS 3.5, to simulate the solid-liquid two-phase fluid inside the tank and describe the sludge concentration distribution. The numerical results indicate obviously a sludge-water interface and a compression interface inside the sedimentation tank, a stratified sedimentary region with uniform concentration and a compression region with high concentration at the bottom of the tank. Although the simulated concentrations deviated slightly from those of in-situ tests, they were still acceptable for identifying the sludge interfaces and fluid pattern inside a sedimentation tank, which are important parameters for optimizing the tank size and improving the settling efficiency. 相似文献