直线永磁振动电机的磁场与静推力特性分析

主要介绍了一种直线永磁振动电机的结构及其工作原理，并用有限元软件对其在不同位置时的磁场进行了分析，同时搭建实验台做了实际的测试，给出了误差及出现误差的原因。该电机结构简单，可靠性高，寿命长，易维护，并且控制电路简单，运行平稳，适用于小功率电磁间的开关系统中。     

PowerBui1der9．0动态下拉数据窗口的应用

本文介绍在PowerBuilder的数据窗口中利用DropDownDW形式的下拉列表输入枚举型数据的方法，既可提高数据输效率和准确性，又可动态更新下拉列表中枚举型数据，提高软件的适应性。     

Skyrmions in a ferromagnetic Bose-Einstein condensate.

Multi-component Bose-Einstein condensates provide opportunities to explore experimentally the wealth of physics associated with the spin degrees of freedom. The ground-state properties and line-like vortex excitations of these quantum systems have been studied theoretically. In principle, nontrivial spin textures consisting of point-like topological excitations, or skyrmions, could exist in a multi-component Bose-Einstein condensate, owing to the superfluid nature of the gas. Although skyrmion excitations are already known in the context of nuclear physics and the quantum-Hall effect, creating these excitations in an atomic condensate would offer an opportunity to study their physical behaviour in much greater detail, while also enabling an ab initio comparison between theory and experiment. Here we investigate theoretically the stability of skyrmions in a fictitious spin-1/2 condensate of 87Rb atoms. We find that skyrmions can exist in such a gas only as a metastable state, but with a lifetime comparable to (or even longer than) the typical lifetime of the condensate itself.     

An Expert System for the Prediction of Surface Finish in Turning Process

Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob lem, an expert system approach is proposed, wherein it will be possible to predi ct the surface finish from limited experiments. The expert system contains a kno wledge base prepared from machining data handbooks and number of experiments con ducted by turning steel rods, over a wide range of c...     

导电混凝土材料电阻系数的研究和分析

作者研究表明：导电混凝土电气加热蓄热冷却过程中温度（t）随时间（z）变化的客观规律可用广义吴震东方程精确描述和控制。在冬季，导电混凝土墙面、地面及水泥混凝土路面在通电加热或融雪化冰过程中的热工计算也可用广义吴震东方程精确地描述，但需要考虑0℃的冰吸热后转化为0℃的水所需的溶解热。基于这一原理建立了导电混凝土融雪化冰新的热力学微分方程及一整套精确的理论公式，其中，电功率（P）的计算与导电混凝土材料的电阻系数（ρ）密切相关，在上述的基础上对导电混凝土材料电阻系数ρ的主要影响因素，作了研究和分析。     

中小企业融资担保的风险与防范

为中小企业融资提供担保，可以保证中小企业融到资金。但是，担保公司却承担着巨大的担保风险，必须采取措施防范融资担保风险，保证担保公司的资产不受损失，实现其良性运作。长期发挥支持中小企业融资的作用。