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。     

论终身学习与数字图书馆

终身学习是终身教育的继承和超越，是人的一切活动的核心。介绍了终身学习的内涵及特征，阐述了数字图书馆以其信息资源数字化，信息传递网络化，资源管理分布化和共事化以及提供个性化智能信息的优势，成为人们终身学习的重要场所。     

“西电东送”工程与“长三角经济带”经济可持续发展

“长江三角经济带”是我国最大的经济核心区，而电力又是制约其发展的一个重要因素。论述了实施“西电东送”，对实现我国能源合理配置，改善电源结构，促进“长江三角经济带”经济发展具有深远的战略意义和作用。