查询词典 structure stability

The method can be used to calculate thin-walled structures not only overall stability but also local stability and interactive stability.

通过算例验证了该方法的可靠性，可以计算薄壁结构的整体稳定、局部稳定和整体局部相关稳定。

However, as we know, the stability condition obtained by method of linear stability is only necessary condition for stability, while subcritical instability cannot be excluded.

Xu[2]用推广的能量方法对该问题的非线性进行了研究，通过定义一个能量泛函，给出当参数时静止状态非线性稳定的充分条件。

Meanwhile,we establishψfunctional stability which is more general than the classical exponential stability and polynomially stability.

我们通过对几类方程的讨论，将不同的渐近稳定性借助于&ψ函数&归结为一种&ψ函数稳定性&。

Therefore, the structure could be stable. However, the structure was changed to amorphous when the strain level was over 15%. At the same time, the binding energy increased rapidly and the structure stability was reduced. During the deformation process, both the bond angle and bond length were significantly affected by the strain level.

这表明Ni纳米线的径向很软，结构之间几乎没有能量转换，且其稳定性基本不变；当压缩程度大于15%时，Ni纳米线结构变为无定形结构，它的结合能变大，且变化很快，表明其稳定性降低；压缩程度对Ni纳米线键角和键长的分布有着很大的影响。

PDC bit crown profile, consisting of single circular arc parabola profile or dual cone profile with deeper inner taper is introduced. Cutter arrangement for various bits is determined. The bit is improved by the application of hybrid cutting structure and detailed analysis of hydraulic structure. Simultaneously, bit stability is enhanced using multiple bit stable structure design techniques such as deep inner taper, force balance and hybrid cutter arrangement etc.

提出了以单圆弧抛物线形轮廓或双锥轮廓配以较深的内锥组成PDC钻头的冠部轮廓，确定了各种钻头切削齿的分布密度，应用了各类切削齿混合设计切削结构，对PDC钻头的水力结构做了详细分析研究；同时，结合深内锥、力平衡、混合布齿等多种钻头稳定性结构设计技术，以增加钻头稳定性。

Geometries of two-dimentional hexagonal net and one-dimentional chain of C36 polymers were optemized by using PM3 and B3LYP/6-31G method. Their electronic structure and stability were also discussed . Band structure were calculated at ab initio level . Compered to the solo C36 molecular ,the results indicated that C36 unit"s structure in the polymers changed obviously and the polymerization increased the system"s stabilities .

本文在系统总结具有纳米尺度的碳团簇研究现状的基础上，着重开展了如下四方面的工作：首先采用PM3和B3LYP／6-31G方法对2D六方网状，以及1D链状C36聚合体的构型进行全优化，探讨了其电子结构和稳定性；并在从头算水平上计算了相应的能带结构。

On the basis of the improved structure and under the premise of meeting specification requirement, the light steel door-truss structure is optimally designed by changing, cycle checking and gradually reducing the cross section size of overall structural member with the ANSYS parametric design language. The mechanical properties such as changes in stiffness, strength and stability of the optimized structure are completely analyzed under three load cases.

基于改进结构，在满足相关规范的前提下，利用ANSYS软件的参数化命令流语言（ANSYS parametric design language， APDL），通过改变结构杆件截面尺寸，对整体结构杆件的截面采用循环校核、递减尺寸，并对轻钢门式桁架结构进行优化设计，分析了优化结构在3种荷载工况组合条件下的整体刚度、强度及稳定性等力学性能的变化，给出了改进前后与优化前后结构的力学特性对比。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

Compared to reticulated structure, it has more stability bearing capacity. So the sheet-space structure is a structure system which has good future.

其稳定承载力比相同条件下的网壳结构有很大的提高，是一种很有发展潜力的空间结构形式。

Referring to the optical rounded reflector of spherical surface used in a space remote sensor, a kind of flexible structure was designed for regulating thermal deformation. Theoretical analysis was done to its dynamic model and parameter of structure, and simulating analysis was also done to reflector module with technology of the Computer Aided Engineering in order to solve the status of high rigidity of structure and poor thermal stability of thermal dimension.

针对某空间光学遥感器的圆形球面反射镜设计了一温升变形调节柔性结构件，对其力学模型及柔节参数进行了理论分析，并采用计算机辅助工程分析技术对反射镜组件结构进行建模和仿真分析，以解决反射镜在力学环境下满足结构刚度要求，而热环境下面形精度显著超差的状况，使反射镜结构刚度满足力学要求的同时，具有良好的热尺寸稳定性，达到遥感器成像质量要求。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。