对称

Experiments show that:when the concentration of acetone is decreased from 100% to 20%,the absorbance bands at 3538cm-1 and 3441cm-1 of CH3 is redshifted,the absorbance band at 1713cm-1 and 1647cm-1 of CO is redshifted about 19 cm-1 and 21cm-1 respectively.

发现随着丙酮水溶液浓度的减小，丙酮CH3键的对称(3538cm-1)和不对称伸缩振动(3441cm-1)吸收峰位置波数减小方向迁徙，CO伸缩振动吸收(1713cm-1)向波数减小方向移动，丙酮浓度为20％时，迁徒至1691cm-1，减小了约19cm-1；同时1647cm-1处的吸收则迁徙至1626cm-1。

On which, the calculating formulas of which circuits are given when they are operated in asymmetric power voltages and currents, as well as in asymmetric reactances and resistances.

分析三相电弧炉电流不对称对等效电阻、等效电抗的影响，在此基础上，对三相电弧炉在电源电压、短网参数、工作电流皆不对称的情况下，给出了计算公式。

In recent years, optically active polymers have attracted much attention because of their unique functions such as molecular recognition, optical resolution for racemates and catalytic activity in asymmetric transformations as well.

近年来，光学活性聚合物的合成与结构—性能研究深受国内外学者的高度关注，这是由于这些合成材料具有潜在的应用前景，如：光学活性聚合物可应用于外消旋混合物的对映异构体分离，即光学拆分过程；不对称吸附、手性诱导及许多有机化学反应过程中的不对称催化。

According to the asymmetry and nonlinearity of the symmetrical valve controlled asymmetrical piston system, in order to improve control precision of the system, the work characteristic of the system is analyzed, then a new control method based on the cerebellar model articulation controller is advanced, and the CMAC compound controller is designed.

针对对称阀控非对称缸系统的不对称性和非线性，为了提高系统控制精度，分析了该系统的工作特性，提出了基于小脑模型神经网络的控制策略，设计了CMAC复合控制器；为验证CMAC复合控制器的有效性，进行了实验研究，并与普通的PID控制器进行比较。

The patient is rotated, as shown by asymmetric comparable ribs in relationship to the pedicles and asymmetric position of the claicles – note the right end of the claicle is quite laterally positioned

患儿拍片位置有点旋转，可以通过椎骨旁的肋骨不对称和锁骨的位置不对称判断出来－注意锁骨的右侧末端位置偏了许多。

Crystals of pure quartz, usually called rock crystal, are coarseness, colorless, and transparent.

答案：D分析及考点：平行对称结构，词性不对称，所以coarseness名词应改成coarse参考译文：纯净石英的结晶，通常称为岩石水晶，是粗糙的，无色的，透明的。

Crystals of pure quartz, usually called rock crystal, are coarseness, colorless, transparent.

答案：D分析及考点：平行对称结构，词性不对称，所以8ttt8 coarseness名词应改成coarse参考译文：纯净石英的结晶，通常称为岩石水晶，是粗糙的，无色的，透明的。

The first one is the system for the two-armed hard-flexible manipulators moving in a certain channel. The dynamic model of that is proposed based on the D'AlembertLagrange principle.

第一个模型研究了由两支对称的刚性-柔性机器臂构成一个双臂机器人的定轨道水平移物问题，利用D'Alembert-Lagrange原理建立了双臂钢性-柔性机器人系统的双臂机器人定轨道移动的非线性对称组合模型。

This thesis mainly calculate and analyze the effect of gravitational gradient based on the torsion pendulum, the result showed that for the modulated torsion pendulum, the torque caused by the gravitational gradient reached to 10~(-12)Nm, while the dissymmetry of round gravitational field can also affect the experiment.

本文主要计算和分析引力梯度效应对弱等效原理实验的影响，结果发现对于调制的扭秤，由于系统的不对称所引起的引力梯度效应达到了10~(-12)Nm，而周围引力场的不对称同样也会对实验产生不同程度的影响。

The article presents the developing condition of PWM and SVPWM first.Then the theory of SVPWM is discussed in detail.The SVPWM is based on the thought of magnetic chain tracking.It makes the ideal magnetic chain circle of three-phased sysmmetry electric motor supplied by three-phased sysmmetry sine wave voltage for basis,uses the practical magnetic chain vector formed by the different switch modes of three-phased inverter to track the basic magnetic chain circle.During the course of tracking,the inverter changes the switch modes properly to form the PWM waves.Then the modulation wave of SVPWM is analyzed in detail.The modulation wave of SVPWM is implicit,but the analogous modulation wave in A-B-C axis needs to be calculated in order to expose the internal relation of SVPWM and SPWM.That is to show the implicit modulation wave of SVPWM. SVPWM actually is a transformed SPWM ruly sampled by the modulation wave which is injected by the zero prefaces based on space vectors.

本文首先对脉宽调制技术的发展现状进行了综述，在此基础上分析了电压空间矢量脉宽调制技术的发展现状；接着对空间电压矢量脉宽调制技术的基本原理进行了详细的分析和推导，SVPWM是基于磁链追踪的思想，它以三相对称正弦波电压供电下三相对称电动机定子理想磁链圆为基准，由三相逆变器不同开关模式下所形成的实际磁链矢量来追踪基准磁链圆的，在追踪的过程中，逆变器的开关模式作适当的切换，从而形成PWM波；然后详细分析了电压空间矢量脉宽调制技术的调制波，虽然SVPWM法的调制波是隐含的，但是为了揭示SVPWM法与SPWM法的内在联系，需要求出SVPWM在A-B-C坐标系上的等效调制波，也就是将SVPWM的隐含调制波显化；SVPWM实质是一种基于空间矢量在三相正弦波中注入了零序分量的调制波进行规则采样的一种变形SPWM。

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％。