关于有心力的几点讨论

讨论2种常见类型的有心力F→=F(r)er→及F→=F(r→)er→的对称性与守恒量;并以→F=(k r2)e→r为例,引入偏心率ε→矢量或Runge-Lenz矢量。     

关于生产力的几个问题的思考

生产力是历史唯物主义大厦的基石，是社会关系的基础，是社会发展的最终决定力量。生产力是由诸要素构成的，其中科学技术处于支配的地位，是第一生产力，笔以马克思关于生产力的有关论述和邓小平关于科学技术是第一生产力”的理论为指导，就生产力的几个问题作初步的探讨。     

框架内力估算

土木结构内力计算的方法存在两大发展趋势，更精确的非线性有限元计算和快速简捷的解析估算，两者有着不同的应用范围。针对建筑结构中常见的框架结构，根据力学的基本平衡原理，引入一支座固定程度系数R，提出了一种非常简便，精度可满足工程要求的估算框架内力的新方法，该方法同时适用于直梁框架和曲梁框架，可供有关人员在方案初步设计和工程现场使用。     

岩石切削力研究

采用单因素法和二次回归正交组合设计法，详细研究了辉绿岩、花岗岩和大理石的切削力性质；提出了合理选择岩石切削加工工艺参数的原则；给出了若干可供岩石切削机械设计使用的切削力经验公式；为进一步建立岩石切削力理论公式打下了基础。     

作用力和反作用力做功与参考系的选取

讨论作用力和反作用力做功及其代数和在不同参考系中的情况．     

Direct measurement of critical Casimir forces

When fluctuating fields are confined between two surfaces, long-range forces arise. A famous example is the quantum-electrodynamical Casimir force that results from zero-point vacuum fluctuations confined between two conducting metal plates. A thermodynamic analogue is the critical Casimir force: it acts between surfaces immersed in a binary liquid mixture close to its critical point and arises from the confinement of concentration fluctuations within the thin film of fluid separating the surfaces. So far, all experimental evidence for the existence of this effect has been indirect. Here we report the direct measurement of critical Casimir force between a single colloidal sphere and a flat silica surface immersed in a mixture of water and 2,6-lutidine near its critical point. We use total internal reflection microscopy to determine in situ the forces between the sphere and the surface, with femtonewton resolution. Depending on whether the adsorption preferences of the sphere and the surface for water and 2,6-lutidine are identical or opposite, we measure attractive and repulsive forces, respectively, that agree quantitatively with theoretical predictions and exhibit exquisite dependence on the temperature of the system. We expect that these features of critical Casimir forces may result in novel uses of colloids as model systems.     

Spiral forces established by optical phase singularities

The spiral forces of phase singularities are demonstrated experimentally and numerically by presenting the generation and propa-gation dynamics of multiple optical vortices embedded in a Gaussian beam. The results reveal that the energy flow established by certain phase singularity will perform the characteristics of force on other singularities whose direction is determined by the sign of the topological charge. The force is confirmed by the fluid-like motions of multi-vortex beams, i.e. singularities undergo rotation (annihilation) with each other when they involve identical (opposite) topological charges. This force mechanism may help develop an intuitive understanding of multi-vortex motion and presents a new viewpoint from which to study the dynamics of singularities     

一个非线性气动力模型的分岔研究

研究一个来自工程中的非线性力学模型,我们运用常微分方程几何理论和非线性动力学的分岔理论对其进行奇点类型分析,讨论其周期运动的存在性和Hopf分岔、全局分岔等问题,并进行数值模拟对理论结果进行验证．通过理论分析和数值模拟的研究方法,得到了所研究系统较为全面的定性结果．     

作用在直立桩柱上的破碎波浪力研究

采用理论分析与实验相结合的方法,对现有的计算作用在直立柱体上的破碎波浪力的各种方法(莫里森公式、冲击绕流法)特点进行了分析。提出了计算破碎波浪力的绕流绕流冲击法,并给出了计算实例。结果表明,用绕流绕流冲击法计算出的破碎波浪力比常规波浪力大约3倍,约为冲击绕流法的2倍。实验结果证实了此法的正确性。本研究可为新滩海海洋结构物的设计和现役结构的安全使用提供理论依据。     

毛细力驱动自组装定位模型

毛细力驱动自组装的定位是利用微元件及基片表面之间的毛细力作用实现的。为了研究微元件及组装区的形状对自组装定位的影响,在分析毛细力驱动自组装机理的基础上,利用能量法建立了毛细力驱动自组装系统的定位解析模型,预测了不同形状微元件的自组装结果,并对一些不合理的组装设计进行了修正。结果表明:通过计算自组装表面能量可以预测组装结果,并设计合理的粘合区形状。