扰动

Fig.6 Images reconstructed of the semispherical head phantom with and without a homogeneous "skull"approximate positions of perturbations, using a 29 mm diameter plaster rod as a perturbation and using a 16 mm diameter cylinder made of copper sheet as a perturbation.

图6扰动在半球形头模型中的大概位置；扰动目标为直径29 mm的石膏柱；扰动目标为直径16 mm铜管

The comparison of the simulations of the same perturbation in 2D and 3D shows that both are similar before the perturbation arrives at 7 solar radii, and that both have the observed three parts of the classical CMEs. However, the reflecting effect of the adopted boundary conditions at both poles in the 3D simulation has a significant effect on the simulation of more hours, and causes unphysical changes in the polar region, such as the enhancement of density and the change of the magnetic field topology.

从对相同扰动的二维和三维模拟结果的对比来看，在扰动到达7个太阳半径之前，模拟结果相似，都可以模拟出CMEs事件的三部分观测特征，但是三维模拟采用的两极边界条件存在的反射效应，对更长时间的模拟有明显的影响，在两极产生密度增强和磁场位形发生较大变化两个非物理扰动。

Distribution region of EDZ and mechanical behaviors of rock mass are further evaluated by using damage model, and the result shows that damage variable is 0.6-0.8 for damaged zone, 0.4-0.6 for affected zone and 0.2-0.4 for slight affected zone. Finally, the slope excavation softening factor is introduced to Hoek-Brown empirical strength criterion, based on the deficiencies of using Geological Strength Index to estimate the rock mass mechanical parameter of EDZ.

对应实测开挖扰动区的分布范围和形状，可以近似确定开挖损伤区岩体的损伤值约在0.6~0.8以内，卸荷影响区岩体的损伤值约在0.4~0.6以内，轻微扰动区岩体的损伤值约在0.2~0.4以内；由此基于Hoek-Brown经验强度准则，引入开挖弱化因子，结合地质强度指标GSI，进行开挖扰动区岩体力学参数研究。

First, the Lyapunov functional and variation of constants method are adopted to study the effect that Sigmoid function and the relation of resistance, capacitance and current in Hopfield neural networks have on the stability of networks. The stability criterion constructed by physics parameters is obtained. Thus how the constrained relation of physics parameters affects the stability of Hopfielf neural networks is clear. Based on the study above, the perturbation model of recurrent neural networks is constructed. And the theorems of the existence of solution of perturbation model are presented.

首先，采用Lyapunov泛函法和常数变易法研究Hopfield神经网络中给出的电阻、电容、电流之间的关系以及Sigmoid函数对网络稳定性的影响规律，得出仅由物理模型参数构成的稳定性判据，从而弄清物理模型参数约束关系对Hopfield神经网络稳定性所起的作用，在此基础上，构建了递归神经网络的扰动模型，并通过讨论扰动模型解的存在性问题，给出递归神经网络扰动模型解的存在性定理。

As to concrete treating method, the thesis adds the components in third dimension to the original 2D MHD code, and inward flows are embedded along the side of the current sheet, through changes of certain flow's scale, its distance to the current sheet, the viscosity coefficient and the resistivity in the plasma, the magnetic field figure, the velocity vector figure and the density distribution figure with different situations would be showed and observed, the reconnection growth rate figure is to be presented also, and the physical explanation involved will be made consequently.

在具体的处理方法上，文章在原有二维MHD流体理论基础上加入第三方向的分量，并且在电流片两侧加入入流扰动，通过改变其大小，距离电流片的位置，等离子体中的粘滞系数和等离子体电阻率，从而观察不同扰动情况下磁场重联的磁场位形、流场位形或者密度分布，绘制出磁场重联增长率在不同入流扰动下的图像，并分析其中的物理过程。

Using the Boussinesq approximation equations for meso-scale disturbances in zonally linear and non-linear shear flows a study is undertaken of the unstable features and wave properties of two typical meso-scale unstable disturbances i. e. symmetric and transversal instabilities.

使用纬向线性以及非线性切变基流下中尺度扰动的Boussinesq近似方程组，讨论了两种典型的中尺度扰动发生对称不稳定或者横波不稳定时，其不稳定的一些特征以及扰动的波动性质。

We investigate detailedly the process of the c - type instability for nonparallel boundary layers with three - dimensional disturbances .

文中通过对三维物体的非平行边界层稳定性的研究，确定最不稳定波的扰动参数和最易失稳的流向、展向位置；对三维扰动的非平行非线性边界层稳定性的研究，得到更精确的扰动放大因子值。

To investigate the dynamic stability of a two-degree-of-freedom manipulator as a system,differential equations of motion for this system were established on the basis of the Lagrange equation,and perturbed differential equations with period coefficients were derived for the period motion of this system by applying the perturbance theory.

为了研究两自由度机械手系统的动力学稳定性，基于拉格朗日方程给出了它的运动微分方程，并用扰动理论确定系统周期运动具有周期系数的扰动微分方程；根据F loquet理论对该系统扰动微分方程的平衡点的稳定性进行了分析，并用数值方法研究了平衡点失稳后的倍周期分岔过程。

The studies show that different types of the oscillation modes of the pulsational instabilities arise from the coupling of radial perturbations to azimuthal perturbations and the vertical perturbations.

结果表明，径向扰动能与环向扰动和垂向扰动相耦合，产生不同类型的脉动不稳定振荡模式。

In order to learn the effect of the random perturbation on imaging quality of the camera during the motion,the process of the dynamic imaging of the camera is analyzed,and the modulation transfer function of the camera is obtained.Then,the influence of the random perturbation,which submits to normal distribution or changes sinusoidally,is studied respectively.

为了描述航天相机运动过程中随机扰动对成像质量的影响，通过分析相机动态成像过程，得到了存在扰动时相机的调制传递函数，并分别讨论了服从高斯分布和具有正弦规律变化的随机扰动对像质的影响。

Singer Leona Lewis and former Led Zeppelin guitarist Jimmy Page emerged as the bus transformed into a grass-covered carnival float, and the pair combined for a rendition of "Whole Lotta Love".

歌手leona刘易斯和前率领的飞艇的吉他手吉米页出现巴士转化为基层所涵盖的嘉年华花车，和一双合并为一移交&整个lotta爱&。

This is Kate, and that's Erin.

这是凯特，那个是爱朗。