查询词典 calculus of finite differences

How to calculate the synthesis operator is the key problem of controlled illumination prestack depth migration. In this paper the inverse time focusing operator is synthesized based on the traveltime calculation method of finite difference approach, and with this synthesis operator the authors calculate the focusing point controlled illumination prestack depth migration using Fourier finite difference. The test results of Marmousi model show its effectiveness and the great advantage of improving computational efficiency.

进行控制照明叠前深度偏移的关键是合成算子的选择，笔者基于有限差分的走时计算方法合成了逆时聚焦算子，基于该合成算子利用傅里叶有限差分法进行了聚焦点控制照明叠前深度偏移，针对Marmousi模型的试算结果表明了该方法的有效性及其在提高计算效率方面的巨大优势。

Deterministic irreducible polynomial and primitive polynomial over finite rings, i. e. polynomial rings with coefficients in finite fields, are obtained.

在系数属于有限域的多项式环即有限环上，给出确定型的不可约多项式和本原多项式。

3D finite element model of concrete pavement in transverse joint with dowel bar s or without dowel bar s is established by 3D finite element numerical analysis method.

建立接缝无传力杆及设传力杆时水泥混凝土面层结构的三维有限元模型，运用数值分析方法，分析接缝处水泥混凝土面层的荷载应力、弯沉值和弯沉差，研究了地基模量、传力杆直径对荷载应力及弯沉差的影响规律，并对条件相同的计算结果进行了对比分析。

Based on the characteristics of structure and loading of the cylinder compress coil spring, the 3D finite element analyzing model of the cylinder compress coil spring in utility is established, and the finite analysis under the static and dynamic loading and life prediction are completed.

在充分考虑圆柱压缩螺旋弹簧的受力及结构特点的基础上，建立了比较符合实际的三维有限元计算模型，并对压缩螺旋弹簧进行了动静态有限元分析，获得了弹簧的刚度，进行了静强度校核、疲劳寿命估算和模态分析。

A methodology to connect microscopic finite element model to macro model is proposed, which is important to carry out multiscale finite element analysis of stuctures.

在有限的计算条件下，为了尽可能的提高结构有限元分析的精度，本文引入了有限元多尺度计算方法。

For the multidimensional representation of finite fields, we define a new Mannheim distance, under which codes over finite fields are discussed.

对有限域的任意多维表示，定义了一种Mannheim距离，并在这种距离之下讨论了有限域上的线性分组码。

Finite element method is based on numerical calculation with the help of matrix and material mechanics and other knowledge, which is widely used in structural analysis ANSYS is a big finite element software integrated with structure, fluid, electric and magnetic field.

有限元法是借助矩阵、材料力学等知识，在结构分析中得到广泛运用的数值计算方法，ANSYS是融结构、流体、电场、磁场分析于一体的大型有限元分析软件。

On the basis of deriving stiffness matrix of an elastic beam unit, the knowledge of computation mechanics and finite element method are used to analyze the strutbeam under distributional load, a finite element analysis result is obtained through an example calculation, which is compared with those of Ansys and material mechanics so as to demonstrate its correctness.

在求出弹性梁单元刚度矩阵的基础上，利用计算力学和有限元法的知识，对分布载荷作用下的简支梁进行了分析。

In this section, we also give a conjecture: A finite lattice is isomorphic to the lattice of flats of a finite poset matroid if and only if it is a semi-modular lattice.

本节的一个中心问题是提出了一个猜想：一个有限格L同构于一个有限偏序集拟阵的闭集所构成的格当且仅当L是一个半模格。

In this paper,we generalize that Polya Theorem for composite of the entire function f is finite order to the form composite and the entire and meromorphic function f is finite order .

将Polya.G关于整函数的复合函数f为有穷级的定理推广到整函数与亚纯函数的复合函数f为有穷级，并得到f为有穷级的一些充分条件

I go to school at night.

我是上上学。

Clear Tip Nasal Aspirator: A soft time and gentle suction action makes removing excess mucus easy.

鼻吸明确提示：一个柔软的时间和温柔吸力行动使消除过剩的粘液容易。