反向运动的

The key components in laser gyro is He-Ne ring laser, and the reciprocal action theory between light and medium is the base in studying the ring laser, use the Lamb half classical theory, and on the base of density matrix theory, the optical Brounch equation was established, which described the movement of amplifying medium atom in the ring syntonic cavity, and according to the medium polarize theory the self consistent equations was deduced, which describe the light intensity and phasic of the counter-propagating wave. On the basis of this equations, adopted the simulation software MATLAB and virtual instrument programming language LabWindows/CVI, we can do some simulated experiments in study the phenomenas such as amplify and dispersive characteristic of medium, mode pushing effection, burned hole effection and pattern competition, lock-in of frequency and the characteristic of light intensity and phasic of the counter-propagating wave in laser gyro.

激光陀螺的核心部件为He-Ne环形激光器，而掌握光与介质的相互作用理论是研究激光器的关键，采用拉姆半经典理论为主，在密度矩阵理论的基础上，推导环形谐振腔中描述He-Ne气体增益介质原子运动的光学布洛赫方程，运用介质极化理论得出描述激光陀螺反向行波的光强、位相所满足的自洽场方程组，在此基础上，运用MATLAB仿真软件和虚拟仪器编程语言LabWindows/CVI，对激光陀螺中的介质增益色散特性、频率牵引效应、烧孔效应及模竞争、闭锁效应及环激光的光强和相位特性进行仿真试验研究，并且运用全量子理论，对激光工作原理进行分析，得出二能级系统单模辐射场的光子数密度分布，得出激光场的光子统计分布，仿真激光场的动态建立过程。

In each of these waves there can be distinguished, first, the actual outbreak of revolution; second, the countermovement and organization of the resistance; and finally, a period of quiescence and adjustment, of stabilization at a new level, until the next outbreak.We can now distinguish three such waves since the sixteenth century.

我们从每一波皆可看出，首先是革命的真实爆发；其次是反向运动及抵制革命的组织；再最后是静止和调整的阶段，在新水平上的稳定阶段，直至下一次爆发。16世纪起到现在我们能看到三次这样的波浪。

The GKS stability theorem for one-dimensional model of hyperbolic initial and boundary value problem, Trefethen's explanation and extension based on the concept of group velocity are generalized firstly. Another possible high-frequency instability mechanism in numerical realization of MTF is pointed out based on his explanation and extension, namely, coupling effect of outgoing harmonic wave along one direction and node motion in the other directions can reverse the energy propagation in multi-dimensional discrete grids.

本文概述了—维双曲型偏微分方程组初边值问题数值稳定性的GKS定理及Trefethen基于群速度概念对这一定理的解释和推广；并应用Trefethen的解释和推广指出了MTF在数值实现中可能出现的另一种高频失稳机制，即在多维离散网格中，沿某一空间方向的外行简谐波，由于与其他空间方向节点运动的耦合效应可以使能量传播方向反向。

In addition, the motion for myosin VI which is opposite to other motors is also intriguing features.

另外，肌球蛋白VI相对于家族中其他分子马达的反向运动也很特殊。

According to Newton's third law of motion—for every action there is an equal and opposite reaction—air streaming out the back faster than the aircraft's speed will thrust the plane forward.

依据牛顿第三运动定律，每个作用力必会产生一个等量而反向的作用力，因此当空气以高于飞机的速度自引擎尾部流出时，便可将飞机向前推。

The control of a robot with unactuated joints is much more difficult than a conventional robot. Because the unactuated joints can't be controlled directly, it is an incomplete controllable system. Usual smooth feedback control is not usable for such system.

引言在一般的机器人控制中，机器人各关节是由各自的电机分别控制驱动的，这样在运动控制上非常简单，一般的只需要做运动学反向解，通过位置反馈控制来实现预定的运动轨道。

Redundant driving structure designed based on a new type of universal Cartesian serial-parallel manipulator, kinetics equations and Euler equations constructed, complete analysis of each jointed points of the moving platform carried out, inverse kinetics solution can be obtained with the given parameters, which include the position and orientation of the manipulator, applied force on the output shaft, parameters of motion of output shaft and connecting bar and sliding block, computer programming adopted to get the valid data and its figure, thus found the perfect show of this redundant driving structure compared to the primary mechanism without redundant driving.

对全新结构的万能直角串并联机构进行冗余驱动设计，通过建立动力学万程和欧拉方程，对机构的动平台各输入铰点处的受力状况进行了全面的分析，已知机构在给定空间位置和姿态下的输出端的受力、主轴的运动参数、连杆的运动参数、水平和垂直运动滑块的运动参数时，可以反向求解机构约动力学反解，通过计算机语言编程计算和绘图得至（直观有效的结果数据，由此得知冗余驱动在改善原机构的动力学特性方面的良好表现。

After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

The opened magnetic circuit is composed as tow NdFeB permanent magnets and a top plate without U-yoke. After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

For example, when joints are practicing yoga in the reverse movement, if the joint beyond the tolerance, caused by pressure on the joints, cartilage damage will be caused traumatic arthritis or degenerative joint disease.

比如练瑜伽时关节都在反向运动，如果超出了关节的承受度，对关节造成挤压，就会损伤软骨，造成创伤性关节炎或关节退行性病变。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。