Electromagnetic modeling of 2D electronic mode‐stirred reverberating chambers for electromagnetic compatibility and interference analysis and design

This research concentrates on developing a complete theoretical tool to analyze the electronic mode‐stirred reverberating chamber. A 2D modeling of the EM fields is performed, which can then readily be extended to a 3D analysis of the cavity. The finite‐difference time‐domain (FDTD) method is implemented to discretize the Maxwell's equations. With our newly proposed method, the electromagnetic‐field characteristics can be easily studied inside the reverberating chamber under a realistic circumstance, thus opening doors to the analysis of a large spectrum of problems related to both commercial and military applications. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

基于集成神经网络的CSTR状态预测

针对连续搅拌反应釜(CSTR)具有的多重稳态性质,提出使用多个相同拓扑结构的神经网络模块组成的集成神经网络对CSTR的状态进行预测的方法。对集成神经网络的所有网络模块使用多目标粒子群优化算法进行同步训练,使训练结果收敛于参数空间内最优的Pareto面。避免了单一神经网络训练收敛到某一最优点可能产生的过拟和的问题;解决了使用传统训练方法对集成神经网络的子网络进行独立训练时增加学习算法复杂度的问题。对CSTR浓度预测的测试结果证明集成神经网络比同等规模的单一神经网络更适用于CSTR的状态参数预测。     

WATER SIMULATION OF SODIUM REACTORS

The thermal hydraulic simulation of a large sodium reactor by a scaled water model is examined. The Richardson Number, friction coefficient and the Peclet Number can be closely matched with the water system at full power and the similarity is retained for buoyancy driven flows. The simulation of thermal-hydraulic conditions in a reactor vessel provided by a scaled water experiment is better than that by a scaled sodium test. The results from a correctly scaled water test can be tentatively extrapolated to a full size sodium system.     

A global study of Kondepudi’s pitchfork

This model reaction, studied so effectively by Kondepudi and his co-workers, is transferred here to a stirred tank. It is shown that, though the rate constants for the two pathways are identical, the stable steady state can still be one in which one or the other pathway is favoured enormously. We are indebted for partial support to the National Science Foundation through heir grant CPE 8112292.     

Hybrid modeling of inulinase bio‐production process

BACKGROUND: A potential application of inulinase in the food industry is the production of fructooligosaccharides (FOS) through transfructosilation of sucrose. Besides their ability to increase the shelf‐life and flavor of many products, FOS have many interesting functional properties. The use of an industrial medium may represent a good, cost‐effective alternative to produce inulinase, since the activity of the enzyme produced may be improved or at least remain the same compared with that obtained using a synthetic medium. Thus, inulinase production for use in FOS synthesis is of considerable scientific and technological appeal, as is the development of a reliable mathematical model of the process. This paper describes a hybrid neural network approach to model inulinase production in a batch bioreactor using agroindustrial residues as substrate. The hybrid modeling makes use of a series artificial neural network to estimate the kinetic parameters of the process and the mass balance as constitutive equations. RESULTS: The proposed model was shown to be capable of describing the complex behavior of inulinase production employing agroindustrial residues as substrate, so that the mathematical framework developed is a useful tool for simulation of this process. CONCLUSION: The hybrid neural network model developed was shown to be an interesting alternative to estimate model parameters since complete elucidation of the phenomena and mechanisms involved in the fermentation is not required owing to the black‐box nature of the ANN used as parameter estimator. Copyright © 2010 Society of Chemical Industry     

Yeast‐mediated stereo‐selective reduction of estrone by continuous cell culture with dual stirred tanks for product yield improvement

BACKGROUND: β‐Estradiol is an important hormone for the treatment of breast cancer and osteoporosis. β‐Estradiol can be produced via Saccharomyces cerevisiae mediated reduction of estrone. However, substrate inhibition and low production yield have been observed in the batch cell culture. RESULTS: An innovative continuous cell culture with dual stirred tanks in series was designed to solve the above problems. The growth medium was fed continuously to the incubation tank where the cells were incubated aerobically; the viable cells were then supplied continuously to the reaction tank in which the yeast‐mediated anaerobic reduction of estrone was performed with continuous feed of the substrate medium and continuous withdawal of the reaction cell culture. Thus, an increase in cell productivity from about 3‐fold to 7‐fold was obtained when compared with the batch cell culture. The β‐estradiol yield was improved to 64.8% on the second reaction day, accompanied by an accumulation of 12.9 mg β‐estradiol on the third reaction day. The yield was about 10% more and the accumulated recovery of β‐estradiol was 4.3‐fold better than with the batch cell culture. The diastereomeric excess value (%de) of β‐estradiol was more than 99%. CONCLUSION: A high product yield with excellent stereo‐selectivity was achieved in a short reaction period with the developed continuous cell culture and the dual stirred tank. Copyright © 2010 Society of Chemical Industry     

不同布水方式下水平潜流人工湿地水动力学机制研究

通过6种布水方式（一般推流、多向入流、部分回流、波流、对角流、多点进水）下水平潜流人工湿地的脉冲示踪剂实验研究，获得其水力停留时间概率分布密度曲线。用4种不同概率分布函数（正态分布、对数正态分布、卡方分布、瑞利分布）对其水力停留时间的概率分布密度进行拟合分析，结果表明：对数正态分布的拟合效果更好。将对流扩散模型和连续反应器模型分别用于6种布水方式下的示踪剂迁移过程模拟，结果表明：连续反应器模型比较适合模拟部分回流式布水方式，对流扩散模型能够较好模拟其他5种布水方式。考虑多向入流和多点进水的示踪剂浓度叠加作用，进一步利用基于对流扩散机制的叠加模型进行示踪剂迁移过程模拟，结果表明：基于对流扩散机制的叠加模型能够较好模拟多向入流、多点进水类型的水平潜流人工湿地。     

KWM卧式搅拌磨机的研制及应用

基于卧式搅拌磨机的工作原理,分析研究了其关键技术,包括筒体磨腔形态、搅拌器形式、密封装置和分级装置等,进而成功开发了KWM卧式搅拌磨机。该设备具有能量密度高、粉磨强度大、产品粒度细和开路磨矿等特点,可用于金属矿和非金属矿的细磨及超细磨作业。最后总结了KWM275卧式搅拌磨机在工业化连续运转过程中的研究成果。