嫦娥三号软着陆近月点和远月点位置的确定

本文分析得嫦娥三号绕月匀速圆周运动轨道至椭圆轨道的交点,由机械能守恒定律得,近月点与远月点处的动能与势能之和相同,应用动能定理可求算出近月点速度大小,根据动能定理和弧长公式,最终确立了两点的具体位置。     

能量守恒定律在制冷循环过程中的解析

能量守恒定律是自然界普遍存在的定律之一,本文通过内能概念,利用能量守恒定律从微观上解释蒸气压缩式制冷的各个过程,从而为我们理解蒸气压缩式制冷原理提供了一个新思路。     

人性遵从的法则

现代量子场论认为，真空是量子场的基态。各个层次以及层次之间的运动变化虽然在现象上纷繁复杂，法则却只有几个，那就是物质不灭定律、能量守恒定律、能量最小原理。同样，动物社会的结构也满足能量守恒定律和能量最小原理，通过竞争处于平衡稳定之中。人立于世上，必须同时满足自身、家庭和社会的需要，所以人性是三重结构优化的结果，这就是普遍的人性，没有特例。     

浅谈动量、动量定理和动量守恒定律的概念和应用

物体的动量比起物体的速度,更能全面地反映物体的运动状态;动量定理和动量守恒定律比起牛顿运动定律,具有更大的普遍性和独立性。本文介绍了动量的概念、动量定理和动量守恒定律;应用动量定理和动量守恒定律求解了典型例题,解题后有说明,点评了本题的重点、难点或解题方法,画龙点睛。     

高分子介质中的能量转换

综述了高分子介质中机械能变热能、声能变热能、辐射能变热能、电能变热能、电能变辐射能、机械能变电能、辐射能变化学能、声能变化学能、机械能变化学能等能量转换的研究近况，并介绍了它们在不同领域的应用前景。     

基于无碳小车的优化设计

基于无碳小车的越障要求,设计一辆无碳小车,在设计、工艺、成本分析和工程管理等方面进行优化设计,通过给予一定的重力势能,依据能量转换的原理,将重力势能转换为动能等机械能来驱动小车行进。     

谈变速技术在引风机节能改造中的选型及应用

引风机是依靠输入的机械能,提高气体压力并排送气体的机械,它是～种从动的流体机械。引风机广泛用于工厂、矿井、隧道、冷却塔、车辆、船舶和建筑物的通风、排尘和冷却,锅炉和工业炉窑的通风和引风等,其能耗较大,因此,对引风机进行节能改造具有很大的经济效益,文章介绍了变频器的调速原理和其优点,分析了变频调速于引风机节能改造中的应用。     

广西百色欲投资7亿元打造稀土铝导线厂

铽镝铁大磁致伸缩材料（简称GMM）是一种新型的电（磁）／机械（声）能换能材料。该材料在磁场作用下可发生位移而做功或反复伸张与缩短，从而产生位移或振动，将电磁能转换成机械能或声能，同时该材料还具有传感功能，即将机械能（如位移、压力、冲击等）转换成电磁能。     

机械传动无碳小车的设计构想

给定一重力势能,根据能量转换原理,设计一种可将该绿色能源重力势能转换为机械能并可用来驱动小车行走的装置。通过不同的条件进行一定的附加设计,达到特定目的。     

液压油泵的工作原理及排除故障

液压泵是液压系统的动力源，也称“动力元件”，它能将原动机（电动机、内燃机等）输入的机械能转换为液压能，用以驱动液压系统中的执行元件。在每个液压系统中，液压油泵是不可或缺的动力设备，液压泵的应用范围比较广，从大的工程机械到小液压工具都离不开液压泵，所以了解液压油泵的工作原理及常见故障是每个工程人员不可缺少的知识。本文就从液压泵的种类、工作原理及常出现的故障进行论述，为工程人员更好的了解液压系统提供基础知识。     

系统的稳定性与不稳定性--搅动能守恒律意义和作用的引伸性讨论

讨论了欧阳首承提出的搅动能守恒律意义和作用，并结合曲率空间做了引伸性的讨论，认为搅动能守恒定律是系统稳定性和演化分析的重要原理和方法，它既是解释系统稳定性的原因，也可以作为系统演化分析的方法，并指出了牛顿体系的某些本质性问题。     

Hypervelocity penetration modeling: momentum vs. energy and energy transfer mechanisms

Analytic penetration modeling usually relies on either a momentum balance or an energy-rate balance to predict depth of penetration by a penetrator based on initial geometry and impact velocity. In recent years, fairly sophisticated models of penetration have arisen that develop the three-dimensional flow field within a target. Based on the flow field and constitutive assumptions, it is then possible to derive a momentum or an energy-rate balance. This paper examines the use of assumed flow fields within a target created by impact and then examines the resulting predicted behavior based on either momentum conservation or energy conservation. It is shown that for the energy-rate balance to work, the details of the energy transfer mechanisms must be included in the model. In particular, how the projectile energy is initially transferred into target kinetic energy and elastic compression energy must be included. As impact velocity increases, more and more energy during the penetration event is temporarily deposited within the target as elastic compression and target kinetic energy. This energy will be dissipated by the target at a later time, but at the time of penetration it is this transfer of energy that defines the forces acting on the projectile. Thus, for an energy rate balance approach to successfully model penetration, it must include the transfer of energy into kinetic energy within the target and the storage of energy by elastic compression. Understanding the role of energy dissipation in the target clarifies the various terms in analytic models and identifies their origin in terms of the fundamental physics. Understanding the modes of energy transfer also assists in understanding the hypervelocity result that penetration depth only slowly increases with increasing velocity even though the kinetic energy increases as the square of the velocity.     

A variational principle for the equations of viscopiezoelectricity

The three-dimensional equations of linear viscopiezoelectricity and an accompanying electromechanical energy theorem are deduced, by the quasielectrostatic approximation, from the equations of viscoelectromagnetism and a generalized Poynting's theorem, respectively. For a viscopiezoelectric solid of volume V and bounding surface S, the internal energy, kinetic energy, and electric enthalpy densities as well as the variation of work done over S and the variation of energy dissipation in V are defined. A variational principle in terms of the defined functions is presented. It is shown that, from the principle, the equations of viscopiezoelectricity in V and the natural boundary conditions on S are obtained.     

建筑爆破倒塌过程的摄影测量分析(Ⅱ)——后坐及能量转化分析

通过前文"建筑爆破倒塌过程的摄影测量分析(Ⅰ)——运动过程分析"中搭建的摄影测量系统,根据图像处理原理以及非量测用摄影机采集到的一系列建筑物倒塌过程的图片的特点——摄影的坐标定位相同,编写图像批处理程序,对建筑物倒塌过程的运动轨迹进行测量。根据摄影测量分析获得的建筑物倒塌过程中的姿态及力学参数,对建筑物爆破拆除过程中后坐现象的形成过程和机理进行了分析,并探讨了建筑物倒塌过程中的势能、动能和机械能的变化和转化的过程。     

铰接盘绕式空间伸展臂屈曲分析理论研究

首先介绍了铰接式可展空间伸展臂设计构造、受力特点与展开折叠机理,然后根据弹性稳定理论与卡氏能量原理,分别推导出局部卷压屈曲和整体螺旋屈曲的临界压力表达式,并据此进行参数特性分析。该文分析理论对铰接式空间伸展臂的设计具有重要指导意义。     

A thermo-micro-mechanical modeling for smart shape memory alloy woven composite under in-plane biaxial deformation

This paper presents a theoretical study of the in-plane behavior of Smart Shape Memory Alloy Woven Composites (SSMAWC) under biaxial loading by developing an integrated micromechanical constitutive model. The model studied in this research is established on the geometric parameters of fibers, metal layers, unit cell, the material constants of composite constituents, and the orientation of fibers, in which the fibers in one direction are SMA ones. The Helmholtz free energy of a Shape Memory Alloy, in 3-Dimensional and 1-Dimensional applications is derived. Using mechanical energy of matrix and elastic yarns, the constitutive relations are developed with the use of strain energy approach and energy variation theorem. The kinetic relations of SMA depicted by Brinson is coupled with the final governing equation of the composite to predict the stress history in smart shape memory alloy woven composites. The deflection of the structure, subjected to uniform biaxial loading is studied numerically. It is found that the effect of Shape Memory Effect (SME) of the SMA wires on the behavior of plain woven flexible fabric composite is significant.     

A discrete mechanics approach to the Cosserat rod theory—Part 1: static equilibria

A theory of discrete Cosserat rods is formulated in the language of discrete Lagrangian mechanics. By exploiting Kirchhoff's kinetic analogy, the potential energy density of a rod is a function on the tangent bundle of the configuration manifold and thus formally corresponds to the Lagrangian function of a dynamical system. The equilibrium equations are derived from a variational principle using a formulation that involves null‐space matrices. In this formulation, no Lagrange multipliers are necessary to enforce orthonormality of the directors. Noether's theorem relates first integrals of the equilibrium equations to Lie group actions on the configuration bundle, so‐called symmetries. The symmetries relevant for rod mechanics are frame‐indifference, isotropy, and uniformity. We show that a completely analogous and self‐contained theory of discrete rods can be formulated in which the arc‐length is a discrete variable ab initio. In this formulation, the potential energy density is defined directly on pairs of points along the arc‐length of the rod, in analogy to Veselov's discrete reformulation of Lagrangian mechanics. A discrete version of Noether's theorem then identifies exact first integrals of the discrete equilibrium equations. These exact conservation properties confer the discrete solutions accuracy and robustness, as demonstrated by selected examples of application. Copyright © 2010 John Wiley & Sons, Ltd.     

水下近场非接触爆炸作用下固支方板破口计算

为研究水下近场非接触爆炸载荷作用下固支方板的破口现象,根据能量守恒原理,假设冲击波能完全转化为结构的初始动能,进而转化为结构的塑性变形能。通过假设变形模式,建立塑性变形能与平板转角之间关系,进而求解平板转角。平板在中间出现破口后,裂纹向外扩展,呈现花瓣状,满足环向应变等于开裂应变条件时裂纹终止,破口达到最大。根据转角大小,可以求解破口尺寸。与通用有限元软件ABAQUS/EXPLICIT计算结果对比,两者吻合较好。工程上,可以利用本文建立的计算方法估算破口大小。     

The Kinetic Energy of the Condensate in the Presence of an External Applied

Average quantities can be determined in many-body physics by the virial theorem even in cases when knowledge about the interaction among particles is not complete. Starting from the virial theorem for superconductivity we obtain an expression for the magnetization of two periodic systems, the infinitely extended film of arbitrary thickness under a perpendicular applied field and the bulk superconductor. We show that the kinetic energy of the condensate can be directly retrieved from the magnetization for a large κ type II superconductor or near the upper critical field, in the pinning free (reversible) regime. Isofield kinetic energy lines for low- and high-T _c compounds have striking differences near the critical transition that clearly indicate for the latter case the presence of a unique superconducting condensate below and above the mean field critical temperature.