Iterative finite element model of nonlinear viscoplastic analyses for blended granular porous media

The iterative finite element model, in which an element is used to represent a single particle, is generated to analyze the global behavior of multiple-material aggregates of materially nonlinear viscoplastic particles. The generalized Maxwell model is used to define four types of specific nonlinear viscoplastic materials, which are the elasto visco-plastic matter with linear viscosity, the plasto visco-plastic material with linear viscosity, the elasto visco-plastic media with nonlinear viscosity, and the plasto visco-plastic media with nonlinear viscosity. The theory and relevant penalty iterative algorithm are developed to analyze the four representative mixed granular systems consisting of materially nonlinear viscous particles. To verify precision of stress calculation, solutions of an axis-symmetric radial flow problem are compared with results of the literature and they are in a great agreement. The results present here provide significant insight into the fundamental behavior of granular media under compaction conditions, including prediction of the overall aggregates stress-strain response.     

煤直接液化中SO2-4 /ZrO2固体酸的催化作用

以二苯甲烷、苯乙醚为煤的模型化合物,以四氢萘(THN)为溶剂,进行中高压加氢液化实验,结合产物的气相色谱和质谱分析,考察了SO2-4/ZrO2固体酸对煤直接液化的催化作用及加氢液化机理.实验结果表明,SO2-4/ZrO2固体酸对模型化合物的转化具有良好的催化活性,与非催化液化相比,400 ℃、H2初压5 MPa、30 min时二苯甲烷的转化率由8.96%提高到61.75%,且模型化合物的存在促进了溶剂THN的转化,上述条件下THN的转化率也达到10.92%;模型化合物及THN的转化主要包括氢解、异构、氢转移及烷基化等反应;SO2-4/ZrO2固体酸的催化作用主要为酸催化的离子反应机理,增强催化剂的酸性有利于煤的催化液化.     

遗传算法在通信网设计中的应用

由于优化问题的非线性，不能用传统的算法解决，本文利用遗传算法解决通信网设计中的优化问题，取得了良好的效果。     

适用于啤酒行业能源管理的智能冷量积算仪

介绍了智能冷量积算仪的测量原理以及软硬件设计，该仪表适用于啤酒行业中冰水和乙二醇水溶液冷量计量，并得到成功应用，具有广阔的应用前景。     

东营市CNG公交汽车改装及加气站经济性研究

对东营市公交汽车改装方案和建设相应的加气站进行了研究，结果表明，以2006年当地90号汽油、0号柴油和CNG价格计算，改装为柴油CNG双燃料公交车比柴油车，每天每车可节省燃料费92．24元，成本回收期为3．6个月；建一座年设计加气量为547．5万m^3、可供200-250辆汽车加气的常规开放式加气站，投资回收期为8年零8个月。改装汽车和建设加气站可利用当地丰富的天然气资源，节约石油，保护环境。     

Nanoindentation mapping of mechanical properties of cement paste and natural rocks

This paper reports a study to assess nanoindentation mapping of mechanical properties of cement paste and natural rocks. Initial work seems to show that mechanical property mapping by nanoindentation is feasible and can be related to microscopic information. Further work is however required on the effect of indent size and spacing. Such a testing technique can be very useful for materials with different phases to study the intrinsic properties of each component, and also the interaction and properties of the interfacial regions of different phases. The values of Young's modulus and hardness of the individual mineral phases were also determined by statistically analysing a large number of experimental data.     

浅埋地下建筑风冷热泵空调系统传热模型与试验研究

本文在浅埋地下建筑风冷热泵空调系统围护结构传热动态模拟的基础上，通过对南京市太园地下旅社围护结构传热的实时测试，验证动态传热模型及计算机模拟方法的可行性和正确性，为浅埋地下建筑风冷热泵空调系统的装机容量、节能指标和设计计算提供一定的理论依据。     

Transient performance study of a brushless doubly fed twin stator induction generator

This paper presents theoretical, simulation, and experimental study of the brushless doubly fed twin stator induction generator (BDFTSIG) dynamics under vector control based on the orientation on the power machine stator flux. A complex transfer function is derived which links the control current and power winding current space vectors in the field coordinates. Based on this result, the transient response of the BDFTSIG to step changes in the control current is examined theoretically. The oscillatory transients are explained in detail and linked to control flux transients triggered whenever operation point of the generator is changed. Furthermore, BDFTSIG operation with closed loop control of the power machine active and reactive powers is examined theoretically and experimentally. It is shown that in the closed loop operation, the system damping may be reduced so that the PI controller gains must be properly selected to achieve a good transient response.     

动力配煤高温复合固硫剂研究

分析了高温复合固硫剂各成分的作用，实验研究了在不同配比的燃烧试验下，各成分对燃煤着火和燃烧以及对炉渣固硫的影响，得出了该煤种高温复合固硫剂的最佳配方。