查询词典 conservation of momentum

To use respectively that rigid body plane differential equations of motion, theorem of angular momentum, conservation law of mechanical energy , and the law of conservation of energy.

分别采用刚体平面运动微分方程、动量矩定理、机械能守恒定律以及能量法，对拟定的半圆柱体微振问题进行分析求解，并作以比较，明确了从不同角度入手分析解决微振动问题所需基础知识和基本理论以及相对难易程

If a body is in the absence of any external torque, the angular momentum of the body is a constant. This is known as law of conservation of angular momentum.

如果物体所受的合外力矩等于零，或者不受外力矩的作用，物体的角动量保持不变，这个结论叫做角动量守恒定律。

Vector nature of angular momentum, precession, conservation of vector angular momentum (its transfer between parts of a system), nutation.

角动量的矢量特性，进动，角动量守恒(它在系统内部之间的转移)，章动。

To ensure the conservation of total momentum and energy of the system, the best discretization form of conservation equations are suggested.

在保证系统总动量和总能量守恒的基础上，提出了离散方程的理想离散形式。

Based on the laws of energy conservation and momentum conservation, the mass-speed equation is derived through Lorentz transformation .

从能量守恒和动量守恒出发，通过洛仑兹变换，推出了质量-速率关系式。

Week 3 Momentum theorem, conservation law of momentum and its application, work of variable force, work of conservative force, potential energy.

第3周 动量定理动量守恒定律及应用；变力的功、保守力的功、势能。

The ones, including conservation of mass, conservation of energy, Newtonian equations of motion, conservation of electric charge, linear momentum principle, continuity equation and Maxwell equations for electromagnet etc., are suitable to all substances. They are universal laws in nature.

连续介质力学的基本方程可分为两类：一类适用于所有物体，构成了自然界的普适规律，如质量守恒、能量守恒、电荷守恒，牛顿运动方程，马克斯威尔电磁学方程、熵产率恒正原理等。

The thesis can be divided into five parts as follows: First, the structural characteristics of finned-pipe evaporator are analyzed. After selecting suitable microelement controller, the heat-transfer and mass-transfer processes are analyzed for every microelement under the conditions of dryness, wetness and frostiness. Based on previous equations, some parameters of frostiness are confirmed and the frost-growing model is set up under frost condition. Some hypotheses are postulated and with the help of the equation of mass-conservation, energy-conservation and momentum-conservation, the evaporation model which fits in the dynamic simulation is built, which set a solid foundation for system simulation. Second, the starting and stopping behaviors under disturbed condition are analyzed and calculated by using the dynamic concentrative parameter model, which gives some advice to better prescribe refrigeration system and set theoretic foundation for carrying out automatic control of refrigeration system. Third, the normal running process is analyzed and calculated by means of rational matching theory, which gives some advice on how to better understand the parameter change under steady state and the affection of inlet-parameter on evaporator. Fourth, the simulation software with dynamic characteristic is designed, which can be applied to calculate thernio-parameter of cryogen, air humidity and frost thickness under different initial and boundary conditions, and to carry out dynamic simulation under conditions of dryness, wetness and frostiness, at the same time, to achieve detection and simulation at any stage from starting to stopping.

本文的主要内容如下：1对翅片管蒸发器结构特点进行分析，选取适当的微元控制体，就干、湿和霜工况下对每个微元分别进行传热传质分析，基于经验关系式确定霜的有关参数，对于霜工况下的霜生长建立模型，经适当假设，运用质量守恒、能量守恒和动量守恒方程建立适合动态仿真的蒸发器数学模型，为系统仿真奠定基础； 2对蒸发在大扰动下的开、停机过程，运用动态集中参数模型进行分析和计算，为更好地描述制冷系统运行的全过程奠定基础，同时也为制冷系统实现自动控制提供一定的理论基础； 3对蒸发器正常运行过程，运用动态分布参数和参数间定量耦合的观点来分析和计算，为更好地了解稳态工况下各点参数的变化情况及各入口参数对蒸发器动态特性的影响即蒸发器性能对各参数变化的敏感性； 4编写翅片管蒸发器动态特性仿真计算程序，可以计算不同边界条件和初始条件下的制冷剂热力参数、空气温湿度和霜厚度分布场，实现对翅片管蒸发器在干、湿和霜工况下的动态仿真。

In this paper, taking one 1900t/h supercritical pressure once—through boiler installed in East boiler company as subject investigated, analyzing the structure and characteristic of unit, from the mechanism of units, based on the law of quality conservation, energy conservation and momentum conservation, having Lagrange fluid particle tracing idea in hydrodynamics field application in analyzing of unit operational characteristic, author build up the nonlinear distributed parameter general dynamic mathematical model of single-phase heating surface or diphase heating surface in the steam-water system for supercritical pressure once—through boiler, which is suitable numerical calculation and simulation for large scale disturbance and full working conditions change, and enough materializing distributed characteristic of thermodynamic parameter in process and time lag characteristic of energy transportation in tache. The transient responses curve of the system main variables under several disturbance are computed by Computer Simulation for the model, and theoretical analysis shows that the simulation results are reasonable.

本文以东方锅炉集团公司的一台1900 t /h超临界压力直流锅炉为研究对象，在分析机组结构和特性的基础上，从机组的工作机理出发，以质量、能量、动量守恒定律为依据，将流体力学领域中的Lagrange流体质点追踪思想用于机组运行特性的分析上，建立了适用于超临界压力直流锅炉汽水系统单相、双相受热面的非线性分布参数通用动态数学模型，该模型适合于大扰动全工况变化的数值仿真计算，充分体现了过程热力参数的分布特性和环节中能量输送过程的时滞特性，并对模型通过计算机仿真得出各种扰动下系统主要变量的响应曲线，从理论上分析了仿真结果的合理性。

The ones, including conservation of mass, conservation of energy, Newtonian equations of motion, conservation of electric charge, linear momentum principle, continuity equation and Maxwell equations for electromagnet etc., are suitable to all substances. They are universal laws in nature.

非线性连续介质力学的基本方程可分为两类：一类适用于所有物体，构成了自然界的普适规律，如质量守恒、能量守恒、电荷守恒，牛顿运动方程，马克斯威尔电磁学方程、熵产率恒正原理等。

In the negative and interrogative forms, of course, this is identical to the non-emphatic forms.

。但是，在否定句或疑问句里，这种带有"do"的方法表达的效果却没有什么强调的意思。

Go down on one's knees;kneel down

屈膝跪下。。。下跪祈祷