内力图的快捷画法

总结材料力学中内力图的简单、易学、快速、准确的绘制方法,以提高学生的学习兴趣和学习效果.     

有压块海底管线水动力特性的实验研究

本文通过模型实验研究了在接近海底平面的波浪场作用下 ,加有压块的水平管的动力载荷 .在 Re=3× 10 3～ 2× 10 4 ,Kc=0 .5～ 15的范围内 ,测量了加有压块的水平管和压块本身的阻力和升力 .采用波面拟合法选取合理的波浪理论 ,本文使用 Stokes II阶波理论确定波浪场的速度和加速度 .     

洛伦兹力的相对论解释

用狭义相对论讨论运动电荷之间的相互作用时，可以推导出洛伦兹力的表达式.并且可以看到电力(库仑力)与速度无关，磁力与速度有关，因而磁力是一种相对论效应..     

碰撞过程的瞬态数字测量

提出了一种对碰撞过程进行瞬态数字测量的方法和仪器装置。它可以用来显示冲击力的时间过程，计算出碰撞过程的冲量从而可以在气轨实验中验证的动量定理。     

电流强度的相对论效应

本文讨论了关于电流方向习惯说法存在的问题,并从相对论的观点给以解释。     

Observation of the V2O5(001) surface using ambient atomic force microscopy

Constant force images of the V₂O₅(001) surface were recorded in ambient conditions with atomic force microscopy. All images exhibit the 11.5 Å × 3.5 Å. periodicity expected for a bulk terminated surface. However, images reveal differences from the ideal structure. The experimental results are interpreted in terms of preferential adsorption sites for water molecules. Because these sites are thought to influence the catalytic properties of the surface, their characterization is an important step towards understanding how the atomic-scale structure of a surface influences its properties.     

我国政府执行力现状及提升对策研究

政府执行力是政府的核心要素之一,是政府组织履行职责与提高自身合法性的重要前提。一国政府要想有效地组织和引导本国社会经济沿着正确的方向发展,必须大力提升政府执行力。党的十七大报告提出了加快行政管理体制改革,形成决策科学、执行顺畅、监督有力的行政管理体制。把执行放在与决策和监督同样的高度,充分显示了执行问题的重要性。提升政府执行力,应变革和创新政府管理理念,合理界定政府职能边界,培育政府执行主体的执行力素质,构建协调高效的政府执行机制,强化责任追究,建立科学的考核机制和执行监控机制。     

Synthesis of high‐molecular‐weight linear methacrylate copolymers with spiropyran side groups: Conformational changes of single molecules in solution and on surfaces

P(BMA‐co‐HEMA‐spiropyran) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization of butyl methacrylate (BMA) and 2‐(trimethylsilyloxy)‐ethyl methacrylate (HEMA‐TMS), removal of the TMS‐protective groups, and the polymer analogous esterification of the hydroxyethyl side chains with a spiropyran containing a carboxylic acid group. UV‐induced conformational changes of the synthesized macromolecules and low‐molecular‐weight spiropyran molecules were studied. Rate constants and half‐life times of the ring closure reaction from zwitterionic merocyanine to the spiropyran species were determined in the presence and absence of mica‐dispersed particles in toluene both with the free spiropyran and the polymer‐bound spiropyran. Scanning force microscopy was used to visualize the conformation of spiropyran‐decorated single macromolecular chains and agglomerated polymer‐bound merocyanine adsorbed on mica. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1274–1283, 2009