Lagrange方程的动力学本质

对广泛应用的Lagrange方程的动力学本质做了探讨,指出在引入速度变换矩阵后,Lagrange方程实际上是牛顿第二定律的一种表示方式;由于引入了速度变换矩阵,Lagrange方程可以方便地在任意的坐标系中建立,对动力学问题的求解提供了一个途径。     

空间振动卸料机的力学分析

利用经典力学和振动学原理建立了空间振动卸料机的力学模型和数学模型，并对其求解。在实验基础上导出阻尼系数的计算公式。     

生产能力扩大的系统动态性研究

利用系统动力学的原理和建模方法描述了企业生产能力与企业物流、信息流与资金流所涉及的各种计划、生产、采购、仓储、销售及财务等职能的关系，利用因果环路图研究分析了生产能力与库存水平、交货期、市场份额、产品价格、成本、利润率、人力等多种因素的因果反馈关系，并构建了生产能力扩大的系统动力学模型来刻画其变化的复杂性与动态性，在两种市场需求（阶跃需求和泊松流随机需求）下模型的仿真结果表明，该模型能较好的反应生产能力扩大的动态行为。     

Molecular dynamics study on the structure I helium hydrate

A 368- water molecule structure I gas hydrate, encased by the number of helium (He) molecules ranging from two to twenty-two, are calculated by molecular dynamical simulations. The potential TIP4P (transferable intermolecular potentical with four sites) is used for water interactions and Lennard-Jones for He-He and He-water interactions. He molecules do not affect the water lattice and can stabilize the hydrate when their concentration is small. A trough signature of He encased is found at 80～90 meV in the phonon density of states. He molecules prefer to be more off-center in 51262 cages. Heavier isotope He are energetically favorable to be filled in cages.     

APPLICATION OF MECHANICAL IMPEDANCE IN VIBRATION ANALYSIS

In the network of a mechanical system,force F and velocity V are related by mechanicalimpedance Z as:Z=F/V.In this paper,we are going to discuss two cases:①Z=0,which gives the frequency equation of the system.We shall use this equation tosolve some practical examples;②Z=∞,which can serve as the design criterion of dynamic dampers.     

一种可视化CFD网格生成方法

结合可视化技术 ,提出一种CFD前处理中的网格生成方法。阐述了CFD前处理中存在的问题 ,并针对这些问题构架起专用的绘图平台。详细介绍了网格划分的思路及实现方法 ,并将网格自动生成模块集成在绘图平台中。实践证明 ,这种可视化CFD网格划分平台操作界面方便友好 ,算法简捷正确 ,大大简化了前处理工作的复杂性 ,具有很高的实用价值     

ANALYSIS OF REGIONAL ECONOMY GROWTH WITH THE THEORY OF DIFFERENTIAL SYSTEM DYNAMICS

In order to describe the interrelation forces among different regions during the economic growth, this paper introduces and analyzes the dynamical system model with the theory of differential systems dynamics. A practical example based on a simplified model is given to analyze the dynamical process of Sichuan economy growth.     

结构动力分析一种简易的直接积分法

本文利用方块脉冲函数优良的运算性质,提出一种结构动力分析简易的直接积分法——方块脉冲函数法,具有无条件稳定的积分格式,并表明方法的可行和有效.     

人类通信模式中基于时间统计的实证研究

最近关于人类通信模式的实证研究显示，信件的回复时间分布具有近似幂律的尾部，其中幂指数在电子邮件和普通信件中并不相同，前者为1．O，后者为1．5。统计了钱学森和鲁迅先生的信件数据，同样发现了近似幂律的回复时间分布，但是钱学森的分布指数是2．1，该发现暗示，将人类动力学划分为两个普适类的猜测可能是不充分的；信件发送的时间间隔分布也服从相同幂指数的幂律分布。同时，截取钱学森连续10年的信件得到的等待时间分布和间隔时间分布与总体基本相似，且幂指数也相同。这种巧合有可能暗示了潜藏在人类通讯模式中的某种未知机制。     

Superhydrophobicity on Micro-and Nanostructured Polyolefin Surfaces:an Experimental and Theoretical Study

1 Results Simultaneous micro-and nanostructuring was prepared on polyolefin surfaces by injection molding.The molds were made of electropolished aluminum foil where the micropatterns were structured with a custom made robot.Nanopatterns were subsequently created on the molds by oxidizing the aluminum surface electrochemically in polyprotic acid.The preparation technique allowed simultaneous control of the dimensions of the micro-and nanostructures.Structuring has a remarkable effect on the contact angle...