Schr(o)dinger方程的时空有限元方法与守恒性

对非线性Schroedinger常微分方程，利用常微分方程连续有限元法证明了能量守恒；对非线性Schroedinger偏微分方程利用时空都连续的全离散有限元方法证明了能量积分守恒和利用空间连续、时间问断的有限元法得到电荷近似守恒，误差为高阶量．并在数值计算上探讨了守恒性和近似程度。结果与理论相吻合．     

SPACE-TIME FINITE ELEMENT METHOD FOR SCHRODINGER EQUATION AND ITS CONSERVATION

Energy conservation of nonlinear Schrodinger ordinary differential equation was proved through using continuous finite element methods of ordinary differential equation; Energy integration conservation was proved through using space-time continuous fully discrete finite element methods and the electron nearly conservation with higher order error was obtained through using time discontinuous only space continuous finite element methods of nonlinear Schrodinger partial equation. The numerical results are in accordance with the theory.     

二维线性哈密尔顿系统的有限元法及辛格式

利用连续有限元法得到了二维线性哈密尔顿系统一次元和二次元的计算格式，并证明了它们都是辛格式．系统的内在特征在离散后能保持．本的数值例子也证实了这些结论．     

抛物方程时间连续有限元全离散格式的超收敛性

利用张量积分解和时间方向单元正交分解,证明了线性抛物型方程的时间连续全离散有限元在单元节点和内部的特征点的超收敛性.并用连续有限元计算了非线性Schrodinger方程,验证了能量的守恒性.计算结果与理论相吻合.     

SPACE-TIME FINITE ELEMENT METHOD FOR SCHRDINGER EQUATION AND ITS CONSERVATION

Energy conservation of nonlinear Schrodinger ordinary differential equation was proved through using continuous finite element methods of ordinary differential equation; Energy integration conservation was proved through using space-time continuous fully discrete finite element methods and the electron nearly conservation with higher order error was obtained through using time discontinuous only space continuous finite element methods of nonlinear Schrodinger partial equation. The numerical results are in accordance with the theory.     

线性哈密尔顿系统的m次连续有限元法

1引 言哈密尔顿系统是一个重要的动力系统,因此如何正确计算哈密尔顿系统有着重要的意义.正确的计算方法离散后应该保持着问题原型的基本特征.其中辛性质和能量守恒是哈密尔顿系统的两个重要特征.冯康和他的研究小组提出了哈密尔顿系统辛几何算法,即算法的每一步进都是辛变换,取得了一系列的优秀成果[1],[2].由辛几何算法构造的辛差分格式能保持该系统基本特征,在有关整体性、结构性、长期跟踪能力上具有独特的优越性.秦孟兆,丁培柱,王雨顺,Marsden,Sanz-Serna,[2,9,11,7,8]等人作了进一步的研究.对线性哈密尔顿系统辛算法能保持能量守恒,但对非线性的哈密尔顿系统,能量为近似守恒.     

哈密尔顿系统的有限元法

利用常微分方程的连续有限元法,结合函数的M-型展开,对非线性哈密尔顿系统证明了连续一、二次有限元分在3阶量、5阶量意义下近似保辛,且保持能量守恒.在数值实验中结合庞加莱截面,哈密尔顿混沌数值试验结果与理论相吻合.     

常微方程组初值问题的连续有限元及守恒性

In this paper the continous finite element to solve initinal value problem for system of linear differential equations is used, and the absolute stability of the corresponding single step k-order hidden shceme is discussed. In the paper by simplified means, the superconvergence of finite element and one of it on the nodes are proved. Using the continuous finite element to solve linear Hamilton systems: Pt = Hq,qt = -Hp, the conservation of energy H(p,q) = 1/2 ap^2 bpq 1/2 cq^2 can be obtained. The computation shows that even if division is regular and the error of finite element Ph, qh is big, H(ph, qh) is almost equal H(p, q) in the range of computation accuracy.     

参数函数和复合函数高阶导数的计算

用函数的链式法则和乘积公式给出了参数函数和复合函数的高阶导数的计算公式．     

提高高等数学教学质量的对策研究

本阐述了当今工科院校中高等数学教学内容、教学方法、教学手段的一些急需解决的问题，并对这些问题作了详细的分析，提出相应的处理对策。