Systems of linear ordinary differential equations with bounded coefficients may have very oscillating solutions

An elementary example shows that the number of zeroes of a component of a solution of a system of linear ordinary differential equations cannot be estimated through the norm of coefficients of the system.

     

CONDITIONS FOR OSCILLATION OF NEUTRAL DELAY DIFFERENTIAL EQUATIONS

In this paper,we study one type of odd-order neutral delay differential equation. Suffcient conditions for the oscillation of every solution to this type of differential equation are given.     

脉冲中立型时滞抛物偏微分方程组的振动准则

考虑一类脉冲中立型时滞抛物偏微分方程组解的振动性,利用一阶脉冲时滞微分不等式获得了该类方程组在Robin,Dirichlet边值条件下所有解振动的若干充分条件.所得结果充分反映了脉冲和时滞在振动中的影响作用.     

某类二阶非线性时滞微分方程的振动性

讨论了一类非线性项具时滞的二阶中立型微分方程的振动性,得到了所研究方程振动的三个充分条件.所得结论推广了已有的相应结论.     

二阶非线性中立型时滞微分方程的振动性

考虑二阶非线性中立型时滞微分方程(x(t)-p(t)x(t-τ))″+∑ from i=1 to n (qi(t)fi(x(t-σi)))=0,t0,其中p,q_i∈C(R+,R+),τ,σ_i∈(0,∞),f_i∈C(R,R),i=1,2,…,n,分别得到了方程所有解振动和方程存在非振动解的充分条件,推广和改进了相关文献中的相关结果.     

一类二阶中立型偏泛函微分方程的振动性

获得了一类具连续偏差变元二阶非线性中立型偏微分方程的振动性的充分性条件.     

一类二阶非线性泛函微分方程的振动性

考虑一类二阶非线性泛函微分方程,得到了方程的解的导数振动的一个充分条件,推广和改进了Lee和Yeh的相关结论.     

Calculation of solutions to the Mathieu equation and of related quantities

For the Mathieu equation, we consider finding eigenvalues with a given index (on the basis of oscillation theorems for the relevant difference equations), the stability of solutions to the difference equations, correct definition and calculation of eigenvalues and Mathieu functions with noninteger numbers, correct definition and calculation of the Mathieu characteristic exponent, and the calculation of values of solutions to the Mathieu equation for large arguments. Numerical algorithms are proposed for the problems listed above.     

Contact friction analysis and stress oscilation suppression with a simple interface element

A simple interface element for analyzing contact friction problems is developed. Taking nodal displacements and contact stresses as unknowns, this element can simulate frictional slippage, decoupling and re-bonding of two bodies initially mating or having gaps at a common inteface. The method is based on the Finite Element Method and load incremental theory. The geometric and static constrait conditions on contact surfaces are treated as additional conditions and are included in stiffness equations. This simple element has the advantages of easy implementation into standard finite element programs and fast speed for convergence as well as high accuracy for stress distribution in interface. Undesirable stress oscillations are also investigated whenever large stress gradients exist over the contact surfaces. Exact integration or the conventional Gauss integration scheme used to evaluate the interpolation function matrix of the interface element is found to be the source of the oscillations. Eigenmode analysis demonstrates that the stress behavior of an interface element can be improved by using the Newton-Cotes integration scheme. Finally, the test example of a strip footing problem is presented.     

DSC Study on Brain Tubulin and the Effect of Cisplatin

Microtubules, a class of cytoskeletal elements, appear to be present in all eukaryoticcells. The temporal and spatial control of assembly and disassembly of microtubulesis believed to be a key factor in cellular function. Microtubules and their subunits(Q-0 tubulin heterodimers, MW 1 10,000) maintain a dynamic equilibrium in the cellcytoplasm. In addition, it is postulated that the lability of cytoplasmic microtubulescaused by drug is related to their equilibrium. Calorimetry method has been…