查询词典 contraction of tensor

By the utilization of the symmetric characteristic of the tensor, algebra relation between the elements in the tensor and refraction index ellipsoid equation, an approach base on Attenuated-total-reflection technology was proposed for the measurement of the QEO coefficient of the organic polymer.

有机聚合物材料的二次电光系数是衡量其二次电光效应的一个重要参数，其可以用一个6×6阶的张量来表示。利用该张量的对称特性、各个元素之间的已知关系以及折射率椭球公式，本文提出了一种基于衰减全反射技术的测量有机聚合物二次电光系数的方法。

This article mainly simulates gradually damage destruction process of rock, major in determinationg the definition of rock three-dimensional damage tensor, simplify to the damage tensor and obtain its engineering calculation method, and obtains the basic expression form of equivalent stress by equivalent stress assumption, symmetrization to the actual stress, thus obtains construction relation of the festival principle of three-dimensional damage rock mass, finally couples elasticity- plasticity with damage in the finite element equation, with reference to elasticity-plasticity gradually degenerated method thought, simulates rock damage to advance gradually the destruction process in finite element method, draws up elasticity - plasticity and damage coupling two-dimension finite element procedure with the C language in the VC contact surface, by simulating experiment destroyed process, acquires destruction image and the axial load distortion curve of model, agreement with the experimental result.

本文主要模拟岩石渐进损伤破坏过程，确定岩石三维损伤张量的定义，对损伤张量进行简化计算并得出其工程计算方法，采用等效应力假设得出有效应力的基本表达形式，对有效应力进行对称化，得出节理损伤岩体的三维本构关系，在有限元方程中实现弹塑性和损伤耦合；借鉴弹塑性渐进退化方法的思想，采用有限元的方法模拟岩石损伤渐进破坏过程，用C++语言在VC界面编制了弹塑性和损伤耦合的二维有限元程序，通过模拟已有的实验破坏过程，得出模型的破坏图像和轴向荷载变形曲线，与实验结果基本一致。

This method is based on tensor and tensor algebra.

中文摘要：提出了一种基于张量学习机的遥感影像目标探测方法。

Briefly covered vector and tensor notation, vector and tensor algebra, wave kinematics, eigenvectors/values, dimensional analysis, and scale analysis.

简要的介绍向量和张量符号，向量和张量代数，波的运动，特徵向量／值，向量分析，以及尺度分析。

PARTⅢMagnetic resonance imaging and diffusion tensor imaging of gray matter damage in multiple sclerosis Objective To study the Magnetic resonance imagingcharacteristics of the gray matter lesions in multiple sclerosis,and to investigate the occult damage in normal appearing gray matterby quantitative analysis using diffusion tensor imaging.

第三部分多发性硬化脑灰质损害的MRI表现及DTI定量研究目的：分析多发性硬化患者脑灰质病灶的磁共振成像特征，利用弥散张量成像定量研究MS的正常表现脑灰质是否存在隐匿性损伤。

Experiments were performed on both synthetic second-order tensor field and real diffusion tensor data set.

在合成二阶张量场和真实扩散张量数据集上进行了实验。

Therefore, topology of second-order tensor field around a degenerate point is determined and theoritic foundation of visualization of the second-order tensor field is built.

从而，定性地确定了简单"退化点"附近特征向量轨迹的拓扑结构。为进一步进行二阶张量场的可视化奠定了理论基础。

A spacetime point with a frame is proposed to be related to a skew-symmetric tensor field of degree 3 defined on Minkowski space, the field consisting of elements in a fixed tensor set.

场中的张量取自于一个固定的张量集合，我们得到了Riemann正则坐标下引力场的一个级数表示式。

According to the similar nature of gravitational field and electrostatic field, using analogy method, the stress tensor in gravitational field is obtained from Maxwells stress tensor in electrostatic field, and the universal gravitation inside t

文摘：根据引力场和静电场的相似性质，通过类比方法由静电场的麦克斯韦应力张量得出了引力场中的应力张量，并用它计算了均质球体内部的万有引力。

According to the similar nature of gravitational field and electrostatic field, using analogy method, the stress tensor in gravitational field is obtained from Maxwells stress tensor in electrostatic field, and the universal gravitation inside the isotropic spheroid is calculated with the obtained result.

文摘：根据引力场和静电场的相似性质，通过类比方法由静电场的麦克斯韦应力张量得出了引力场中的应力张量，并用它计算了均质球体内部的万有引力。

So it was last week in Selma , alabama.

上星期在亚拉巴马州塞尔马市发生的事件也是这样一个转折点。

The group also spearheads various social programs in China.

该组织还带头参与中国的各种社会活动。