查询词典 symmetry

In consideration of the cyclic symmetry of displacement constraints of group blades, a skew boundary condition and a skew coordinate system are introduced to deal with the constraint condition of group blades or integral blades.

该模型考虑到成组叶片位移约束的周期对称性，引入了料边界条件和斜坐标系统来处理成组或整圈叶片的约束条件，从而可以准确地计算出三维复杂形状叶片组在动、静状态下的固有频率和振型。

By setting symmetric orbit traps (in particular, by using more complex bounded sets, such as chaotic attractors, as orbit traps), visually fascinating images with cyclic or dihedral symmetry can be created in this way.

通过设置具有对称性的轨迹井(同时也把轨迹井推广到更加复杂的有界集上，如混沌吸引子)，生成具有循环群对称性的彩色图像。

of the mistuning effects on thedynamics of the bladed disk are summarized. The bladed disk assemblies are cyclic symmetry structures.

谐调叶盘系统为循环对称结构，而失谐的存在破坏了这种循环对称性，并造成叶盘系统模态的局部化现象。

The results indicated that the centrifugal force reduces the localization; when the Young's modulus of all blades are in the tolerance of 5%, the blade-disc can regarded as an cyclic symmetry system. The study results given in the present paper have provided a variety of effective numerical methods for the study of vibration characteristics of blade, disc and the blade-disc system. These research results can also serve as a helpful guide to the vibration study of other rotating components.

本文的研究成果为汽轮机关键部件叶片—轮盘系统的振动特性研究提供了一些有效的数值方法，得到了一些结论，对工程具有较大的现实意义，同时对其他叶轮机械旋转部件的振动研究也有参考价值。

Based on Three Gorges Project, the following aspects about the three typical embedding manners are studied:(1) The border condition of cyclic symmetry is applied to the finite element models with contact among cushion layer, penstock and concrete. The effects of elastic modulus, thickness and placement extent of cushion layer on the stress of its around concrete are analyzed. It is suggested that the ratio of thickness to elastic modulus can be used as an important parameter in the design of cushion layer.

因此，本文结合三峡工程建设实践，在收集和总结前人经验的基础上，以大型通用有限元分析软件ANSYS为平台，对不同埋设方式的巨型蜗壳结构进行以下几个方面的研究：(1)引入循环对称边界条件，考虑垫层-钢板-混凝土之间的接触摩擦，建立有限元模型；并对垫层敷设范围、垫层厚度和弹性模量等设计关键参数进行了优化，并把"垫层弹性模量与垫层厚度之比"作为参考指标进行设计。

The cyclic symmetric conditions of node points are presented to modify the stiffness and mass matrices of the substructure.With the use of the structural cyclic symmetry and the complex constraint conditions,the eigenvalue ...

这证明复约束法既极大地减少了计算所需内存和机时，又可建立包含轮齿和轮体在内的计算模型，保证了齿轮结构特征值问题计算的完整性和准确性。

Cyclic symmetry in blade-disc assembles is often destroyed by small differences in the individual blades'structural properties that result from manufacturing and material tolerance, this phenomenon commonly knows as mistuning.

建立了某汽轮机叶片—轮盘的有限元模型，研究了离心力对失调叶片—轮盘系统振动的影响；利用概率分析方法，研究了所有叶片弹性模量在5%误差范围内随机失调叶片—轮盘振动情况。

The static natural frequencies and dynamic frequencies (under 3000rpm) are calculated by the finite element method and cyclic symmetry technique. The rotating vibration behaviors of the two models are compared. Different vibration characteristics between the two models are discussed. Geometry mismatch in a turbine blade root, which arose in manufacturing process or caused by wearing out during service, leads to contact conditions changed in fir-tree attachments. As a result, shifting of the fundamental frequencies and redistribution of stress in the blade base possibly cause failure of the blade.

在叶片—轮盘耦合系统振动研究方面，建立了带围带的叶片振动计算模型和带围带的叶片—轮盘耦合系统振动计算模型，考虑旋转离心力作用，采用波传播技术，对两种模型分别进行了整圈模态分析，得到了某汽轮机叶片模型和叶片—轮盘耦合模型在0转速和工作转速(3000rpm)下的振动模态，并对所得结果进行分析比较，讨论了整圈叶片振动模态与叶片—轮盘耦合振动模态的区别。

The copolymerization of cycloolefin and α-olefin, and structure of the obtained polymer are significantly affected by the structure and symmetry of metallocene catalysts, electronic effect and steric hindrance of ligands.

着重介绍了加成聚合法中茂金属催化剂的结构对称性、配体的电子和体积效应、反应条件等对聚合活性、产物组成与序列分布及相关热性能的影响。

The copolymerization of cycloolefin and α-olefin,and the structure of the obtained polymer are significantly affected by the structure and symmetry of metallocene catalysts ,electronic effect and steric hindrance of ligands.

着重介绍了加成聚合法中茂金属催化剂的结构对称性、配体的电子和体积效应、反应条件等对聚合活性、产物组成与序列分布及相关热性能的影响。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。