守恒

With the modernization of scientific and technological progress and industrial development, physics, chemistry, biology, engineering, aerospace, medical, economic and financial areas of the many principles and laws can be described as an appropriate ordinary differential equations, such as Newton's laws of motion, gravity law, law of conservation of mechanical energy, energy conservation law, the law of population development, ecological population competition, disease transmission, genetic variation, the trend of the stock's up V, the floating interest rates, the market equilibrium price changes.

随着科技进步和工业现代化的发展，物理、化学、生物、工程、航空航天、医学、经济和金融领域中的许多原理和规律都可以描述成适当的常微分方程，如牛顿的运动定律、万有引力定律、机械能守恒定律，能量守恒定律、人口发展规律、生态种群竞争、疾病传染、遗传基因变异、股票的涨伏趋势、利率的浮动、市场均衡价格的变化等。

The bland sameness of space is at the root of both momentum conservation and angular-momentum conservation.

平淡无奇的空间一致性，既是动量守恒的根本，又是角动量守恒的根本。

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。

Chapter two proposes the unified form of Hojman"s conservation law and Lutzky"s conservation law. Firstly, the author introduces the general Lie group of transformations that the variations of both the time and the generalized coordinates are considered, derives the determining equation of Lie symmetry for the system, presents a new conservation law, which contains the Hojman"s and the Lutzky"s conservation law as two special cases, and obtains a condition to exclude trivial Hojmans conserved quantities.

第二章，Hojman定理和Lutzky定理的统一形式：首先，引入一般意义下的Lie变换群(即位型变量q_s和时间变量t同时变换)，给出系统的Lie对称性确定方程，提出一个新的守恒律，Hojman定理与Lutzky定理则分别是这个新守恒律在两个特殊情况下的推论，导出一个可排除平凡Hojman守恒量的定理，并分别讨论了Birkhoff系统和非完整系统的Lie对称性和Hojman守恒量，最后，讨论了Hamilton系统的梅对称性与Lie对称性的关系，给出了由梅对称性求Hojman守恒量的方法。

According to Orowan's investigation results, the amount of plastic work Γ is three orders larger than that of surface energy. However, the yielding of metal material is only associated with the deviator strain energy.

由于引起金属材料屈服的原因仅为偏斜应变能，而与体积应变能无关，本文提出了一个与路径无关的守恒积分，即偏斜应变能积分，并对其守恒性进行了严格的证明。

The parity-violating energy difference of D- and L-alanine was undertaken as a function of the dihedral angle θ of the carboxylate plane with respect to the Cα-Hα plane.

自然界的力只有弱力是宇称不守恒的。在分子物理中，电弱力宇称不守恒是导致D-和L-丙氨酸能差的根源。

Compared with the initial value problems of scalar conservation laws with smooth flux function, the global weak entropy solutions for the initial-boundary value problems of scalar conservation laws with weak discontinuous flux function include the following new interaction types: a rarefaction wave collides with the boundary and is absorbed compltetely or partially by the boundary; a rarefaction wave collides with the boundary and the boundary will reflect a contact or non-contact shock wave; a contact or non-contact shock wave collides with the boundary and is absorbed by the boundary; a contact or non-contact shock wave collides with the boundary and a new non-contact shock will rebound from the boundary simultaneously or later.

与具有光滑流函数的单个守恒律的初始值问题相比，具有弱间断流函数的单个守恒律初边值问题的整体弱熵解中包括下列新的相互作用类型：稀疏波碰到边界并被边界部分或全部吸收；稀疏波与边界相撞，边界反射出一个接触或非接触激波；接触或非接触激波碰到边界并被边界吸收；接触或非接触激波与边界相撞，边界同时或稍后反射出一个新的非接触激波。

The effect of upper tropospheric perturbation PV on the development of the South-West Meso-cyclogenesis is discussed on Hoskins PV Principle in terms of conservation of PV on isobaric surface and humid isentropic PV.Upper tropospheric perturbation PV,which dilates slantwise downward and southward,is found to be an important factor to influence the low-level South-West Mesocyclone.

基于Hoskins位涡理论思想从等压面位涡守恒和湿等熵位涡守恒的角度来研究对流层高层位涡扰动对低层西南涡的发生发展影响，发现对流层高层位涡扰动是影响西南涡发生发展的重要因素，它对西南涡的影响表现出它有向南向下倾斜伸展的特点。

By using the theories of conservation of momentum,conservation of energy and hydrokinetics,a mathematical model for describing the relationship among the fluid parameters,the formation parameters and the vibrant operation parameters was established.The analytic solutions of one-dimensional and radial transfusion equation for compressive and single-phase fluid flow through the compressive formation were obtained.The effects of each parameter on the vibrant operation were also gotten.On the basis of the above results,the computation models were established.

应用动量守恒、能量守恒、流体动力学等基本原理，建立了地层参数、流体参数和振动作业参数之间相互耦合的数学模型，求出了单相微可压缩流体在可压缩地层中的平面一维和平面径向渗流方程的解析解，得到了各项参数与振动作业效果之间的关系，为振动采油的数值模拟提供了初始压力分布表达式。

Methods By using the theories of conservation of mass, of energy, Darcy's law and hydrokinetics, the mechanical model of oil layer fluid under the function of low frequency vibrated wave was studied. With the combination of indoor experiment and the numerical simulation, the effect of downhole low frequency vibration on oil viscosity, interfacial tension, capillary pressure, producing water cut and the rising velocity of it was studied quantitatively.

应用质量守恒定律、能量守恒定律、达西定律、流体动力学等基本原理研究了低频振动波作用下油层流体的数学模型，将室内实验和数值模拟技术相结合定量地研究了低频振动对原油私度、界面张力、毛管压力、产水率及产水率上升速度的影响。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。