使守恒

Firstly, using strategy of introducing associated auxiliary equation to a givenpartial differential equation without admitting Lagrangian, we make the extendedequations possess a variational principle. Based on this, the concepts of extendedconservation law and extended symmetry to given partial differential equationare put forwarded.

首先，我们给出了引入伴随方程扩充原方程的策略，使给定偏微分方程的扩充方程组具有对应泛函，即称为Lagrange系统的方法，以此为基础提出了作为偏微分方程传统守恒律和对称概念的一种推广—偏微分方程扩充对称和扩充守恒律的概念；其次，先给出以得到的Lagrange系统为基础，利用N？

This makes more and more people pay more attention to studies and applications of numerical simulation in thermal recovery. In this research, we have developed a reliable mathematical model for thermal recovery, which takes a full consideration of the effect of viscos, gravitical and capillary forces on the three-phase flow of gas, water and oil, the effect of the temperature on the medium characteristics of liquid and solid, the phase equilibrium of gas-liquid in each component, heat transportation including connection, conduction and radiation as well as heat losses in both the overburn and underlying strata. In the space discreation of the mathematical model, we have proposed a new method based on the improvement of the conventional nine-points difference approximation, which has a higher difference accurancy.

本项研究以热力采油的主要机理为基础，充分考虑在粘性力、重力和毛管力作用下油水气三相流动，考虑温度对各种流体和固体介质物性的影响，考虑每一组分中汽液两相的相平衡，考虑热在地层中的传导、对流和辐射以及上下盖层的热损失，利用热力学第一定律、质量守恒定律和流体迁移定律，建立了正确可靠的注蒸汽数学模型；在对数学模型进行空间离散时，利用控制有限体积积分法，对以往的九点差分近似作了合理的改进，使其具有较高的差分近似精度：结果表明，该公式的近似精度要比以往文献中所给的九点差分近似精度高，可以认为，在油藏数值模拟中，如果遇到非均质情况，使用这种九点差分近似更合理。

Multiple blood samples were taken for measurement of the time course of the drug concentrations, and the electrocorticogram processed (approximate entropy, for propofol and methohexital and percentage high frequency time, for ketamine) to numerically quantify drug effect.

结果：使用药代/药效分析法得出的t1/2Keo：氯胺酮为2.0±0.4min，异丙酚为2.7±1.1min，而美索比托的t1/2Keo为0.3±0.1min明显较前两者缩短。药代/药效分析法和总体守恒分析法在药物到达峰值的时间举无明显差异。

Developments in physics since the time of Newton make the law of momentum conservation appear to be more fundamental than Newton's third law.

牛顿时代以来物理学的发展，使动量守恒定律显得比牛顿第三定律还重要。

To use the field concept and its language consistently, we must regard the magnetic field as a store of energy. Only in this way shall we be able to describe the electric and magnetic phenomena in accordance with the law of conservation of energy.

为了一致地应用场的概念和它的语言，我们必须将磁场当作能的储存所，只有这样才能使我们能够按照能量守恒定律来描述磁和电的现象。

In Chapter 3 relaxation in growth with a conservation law is studied, and reduced roughness of the surface due to the effect of relaxation is found. The last chapter includes discussions of point defects in conservational surface growth.

第三章研究了守恒界面生长中界面弛豫效应的影响，发现弛豫作用使得守恒生长的界面粗糙程度下降；第四章研究了杂质点缺陷的存在对生长表面的影响，发现存在于生长的活跃表面层中的点缺陷会使表面的局域粗糙度增加。

EMHYDR HR oils have excellent oxidation stability and demulsibility, enabling ready separation of entrained water and giving long life without formation of harmful sludge.

守恒定律使我们能够就可得出有关原子稳定性的具有深远意义的结论，而不需要对原子核内起作用的力作任何假设。

Based on the analysis of current oscillation region of stable electric fielddomains in I-V curve,it is shown that when the applied bias voltage is changedwithin positive slope regions of I-V curve,the domain boundary between the high-and low-electric field domains does not moved,and the size of electic fielddomains regions is also not altered,while the electric filed strengths are adjusted tokeep the current conservation.

通过对稳态电场畴情况下I-V曲线中电流振荡区域的分析，证明当外加偏压在正微分电导区变动时，超晶格的高低电场畴之间的畴边界不发生移动，畴的大小不变，只是相应的电场强度做些调整以使电流守恒成立。

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％。