查询词典 algebraic form

We develop his ideas by finding some algebraic invariants under the adjoint actions of the group in addition to the Killing form and give a rigorous proof of the optimality of the one-parameter systems for the symmetry group of the given equations.

本文系统地研究了1+2维非线性发展方程的对称代数，证明了该方程容许一个七维李点对称群，利用Olver提出的方法，详细地建构了1+2维非线性发展方程的一维最优系统，在此基础上我们发展了他的方法，发现了除Killing型之外的其它六个在群伴随作用下的代数不变量，利用这些不变量证明了该最优系统的最优性。

They are studied for their global properties by the methods of algebra and algebraic topology and form a natural domain for the global analysis of differential equations.

它们的整体性质用代数和代数拓扑的方法进行研究，并且形成微分方程式的整体分析的一个自然的领域。

For a general parametric curve/surface, we usually cannot compute its exact implicit form. Even though its exact implicit form can be computed, the curve/surface implicitization involves relatively complicated computation and the degree is higher. Moreover, it may have unexpected components and self-intersections. All these unsatisfied properties limit the applications of the exact implicitization. So finding curve/surface approximate implicitization has become a practical problem. In this paper, we present an algorithm to solve the approximate implicitization of a given parametric curve by using a quadratic algebraic spline curve.

由于精确隐式化过程不一定可以实现，即使可以实现隐式曲线曲面的阶数高计算复杂，并且具有不希望的自交点和奇异分支，从而限制了隐式化的运用，所以寻求参数曲线曲面的近似隐式化问题成为很实际又重要的问题，提出利用二次代数样条曲线来实现一般平面参数曲线近似隐式化的一种算法。

Since the method does not need to derive the concrete form of the transformation matrix, making it simple and easy to calculate the results to the eigenvalue problems of the Hamilton with symmetrical form. This algebraic methods is more universal and more effective.

由于该方法不需要求出变换矩阵的具体形式，使得运用此方法求解具有对称形式的Hamilton量的本征值问题变得简单、易计算出结果，该方法更具有普遍性，是一种十分有效的代数方法。

First, a simple criterion on the delay-independent asymptotic stability has been derived in the form of the algebraic Riccati inequality and algebraic Riccati equation for the linear systems with time-varying multi-state delays.

4针对工业生产中广泛存在的不确定时滞过程，研究了时滞系统的渐近稳定性的判定方法和镇定方法。

Put the discrete algebraic equations of initial derivative conditions and algebraic equation system of governing differential equation together to form a new algebraic system.

采用重心Lagrange插值近似未知函数，推导了未知函数各阶导数微分矩阵的显式表达式，建立了求解二阶常微分方程初值问题的重心Lagrange插值配点法。

In the light of the complex, high-level and non-linear feature of the mathematical model which describe the transport of the coalbed methane, this paper study the fully-implicit solving method of the mathematical model in detail. Based on the complexity of the algebraic equations which are formed eventually, according to the alternating direction implicit difference pattern, this paper use the iterative method and the fully main element Gauss-Jordan eliminating method to solve equations, which is to use the iterative method to determine coefficient matrix and use the fully main element Gauss-Jordan method to solve th linear algebraic equation group, at the same time of studying the solving method of the mathematical model, according to the devising requirement of FORTRAN77 program structure, this paper draw up computer program and form the corresponding computer model, and verify the validity and reliability of the model in theory by operating the model.

重点研究了模型内、外边界及有关参数的处理，针对描述煤层甲烷运移的数学模型是一个复杂、高阶非线性数学模型的特点，详细研究了模型的全隐式求解方法，根据最后形成的代数方程组的复杂性，按交替方向隐式差分格式，采用迭代与全选主元高斯约当消去法相结合的方法求解方程：即确定系数矩阵采用迭代法，求解线性方程组时采用全选主元高斯约当消去法，在研究模型解法的同时按FORTRAN结构化程序设计的要求，编制计算机程序，形成相应的CBMRS计算机模型，并通过模型的运行从理论上证明了模型的正确性与可靠性。

Main contributions and achievements are as follows:A general non-equilibrium rigorous model for RDP is developed in this thesis. Based on the pseudo-homogenous assumption, two main factors reaction and separation are de-coupled, and an RDP model with the same format as that for a traditional distillation process is established. To solve the model with a large number of algebraic equations, modified M-K equations with tri-diagonal matrix form are developed based on the improved Separation Efficiency Functions, which greatly increases the iteration efficiency. This thesis also develops a general reactive distillation dynamic model. Through splitting of the differential variables based on SEFS, large-scaled differential algebraic equations can be solved with the improved Gear's algorithm which makes the dynamic model suitable for the on-line application. A simulation platform for the control loop design and evaluation of RDP by introducing control system equations into the dynamic model is also developed.A lactic acid purification pilot-scale RDP is investigated.

论文对热点问题——反应精馏过程的建模与优化控制相关技术进行了深入的研究，取得了一系列成果：1、建立了反应精馏过程机理模型，基于拟均相假设，将反应和分离过程进行解耦，推导出反应精馏过程的非平衡级稳态模型和动态模型，通过引入推广的分离效率函数，对模型变量进行了合理划分，显著提高了模型求解效率；将动态模型和控制系统方程结合，建立了反应精馏过程控制系统研究的辅助工具。2、全面分析了乳酸提纯反应精馏新工艺试验装置，利用本文建立的过程机理模型，对该试验装置进行了稳态和动态性能分析及水力学核算；设计和分析了单边质量控制方案，比较了间接和直接物料平衡控制两种方案的控制性能。

Applying the techniques of real radical ideal, P-radical ideal , decomposition of semi-algebraic set in ( [72] ), affine Hilbert polynomial and B-net form of polynomials on simplex, this paper obtains two theorems of real C〓 piecewise algebraic variety dimensions and the real Nullstellensatz in C〓 spline ring.

4：应用多项式在单纯形上的B-网形式以及文献（[72]）中的实根理想，锥根理想，半代数簇分解定理，本文得出了实C〓分片代数簇的二个维数定理和C〓样条空间的实零点定理。

But , when we changeour trainofthought , we can find that sometimes using mathematical Analysis is a better solution to the linear algebraic problems.In thispaper, use the propertyofcontinuous function andimproper integralof infinite interval and to solve some matrix and quadratic form problems.Algebraic ideas andmethodstosolvemathematical analysisproblems are indicated by several specific examples. Close contactof differentmathematical analysis fields is shown.

该文探讨运用数学分析的有关知识（如：函数连续性、无穷区间的广义积分）和方法解决高等代数中的某些复杂、繁琐的问题；通过具体的实例，阐述高等代数的思想和方法在解决数学分析问题中的作用，揭示不同的数学领域之间的密切联系，例如：二次型与正交变换是代数学的基本内容，其用途十分广泛，而重积分的计算往往存在技术性的困难，若利用"二次型"与"正交变换"的有关理论去解决某些重积分的计算问题是颇有功效的。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。