多组分传质过程的Maxwell-Stefan方法模拟

为定量研究多组分系统在多孔介质内传质过程中组分之间的交互作用现象,本文基于Maxwell-Stefan模型对CH₄/Ar/H₂混合气体在单个直孔道内的纯扩散过程和C₂H₆/C₃H₈/N₂混合气体在活性炭上的吸附扩散过程进行了模拟,定量地描述和分析了多组分系统中组分之间在传质过程中的交互作用。研究表明:对于扩散过程,组分之间的交互作用表现为大分子对小分子的拖带;对于吸附过程,这种作用表现为强吸附质能够替代已被吸附在吸附剂表面的弱吸附质;主体扩散为主要的传质形式。     

二粒子Boltzmann方程组的奇异扰动解法

讨论了二粒子Boltzmann方程组的边界层解.为此我们先对未知变量进行了Fourier变换,然后运用前人的方法对变换后的函数进行展开.通过对未知变量做一些特殊的函数展开,得到了二粒子Boltzmann方程组的正规解和边界层解,并得到了边界层解的初级和高级近似.     

Image normalization of Wiener-Hopf operators and boundary-transmission value problems for a junction of two half-planes

The present paper deals with an application of the image normalization technique for certain classes of Wiener-Hopf operators (WHOs) associated to ill-posed boundary-transmission value problems. We briefly describe the method of normalization and then apply it to boundary-transmission value problems issued from diffraction problems for a junction of two half-planes, which are relevant in mathematical physics applications. For each boundary-transmission value problem, we analyze the conditions under which the associated operator and the equivalent WHO are not normally solvable, and define the corresponding image normalized operators.     

由卷积和从属关系刻画的单叶调和函数某些子类

Let SH be the class of functions f = h + ˉg that are harmonic univalent and sensepreserving in the open unit disk U = {z ∈ C : |z| 1} for which f(0) = f′(0)-1 = 0. In the present paper, we introduce some new subclasses of SH consisting of univalent and sensepreserving functions defined by convolution and subordination. Sufficient coefficient conditions,distortion bounds, extreme points and convolution properties for functions of these classes are obtained. Also, we discuss the radii of starlikeness and convexity.     

关于二阶半线性椭圆方程的Dirichlet边值问题一个注记(英文)

本文研究二阶半线性椭圆方程的Dirichlet边值问题.利用山路引理和最小作用原理,获得了在新条件下具有Dirichlet边值问题的二阶半线性椭圆方程的弱解的存在性的结果.     

A 3D non-Newtonian fluid-structure interaction model for blood flow in arteries

The mathematical modelling and numerical simulation of the human cardiovascular system is playing nowadays an important role in the comprehension of the genesis and development of cardiovascular diseases. In this paper we deal with two problems of 3D modelling and simulation in this field, which are very often neglected in the literature. On the one hand blood flow in arteries is characterized by travelling pressure waves due to the interaction of blood with the vessel wall. On the other hand, blood exhibits non-Newtonian properties, like shear-thinning, viscoelasticity and thixotropy. The present work is concerned with the coupling of a generalized Newtonian fluid, accounting for the shear-thinning behaviour of blood, with an elastic structure describing the vessel wall, to capture the pulse wave due to the interaction between blood and the vessel wall. We provide an energy estimate for the coupling and compare the numerical results with those obtained with an equivalent fluid-structure interaction model using a Newtonian fluid.     

图的符号团边控制数

本文研究了图的符号团边控制数的问题.利用鸽巢原理,获得了图K_n∨P_m和K_n∨C_m的符号团边控制数,推广了已有的结果.     

关于数列极限概念教学的调查分析

通过对兰州城市学院相关专业165人的调查，分析该校在数列极限ε-N 定义的教学中存在的问题，并给出解决问题的应对措施：依教材为范本，做好由具体到抽象的过渡教学；加强“证明”作用的教学；加强反例教学；及时耐心地纠正学生错误。     

带谱参数边界条件的四阶边值问题的矩阵表示

研究了一类具有有限谱的带有谱参数边界条件的四阶微分方程边值问题及其矩阵表示,证明了对任意正整数m,所考虑的问题至多有2m+6个特征值,进一步给出这类带有谱参数边条件的四阶边值问题与一类矩阵特征值问题之间在具有相同特征值的意义下是等价的.     

Numerical study of an equation related to wave propagation

We discuss two algorithms for the computation of approximate solutions of a generalization of the so-called Benjamin-Bona-Mahony equation, which is a model proposed to describe unidirectional propagation of long water waves. Both schemes discussed are quadratically convergent with respect to Δt in theH ¹-norm. They use the Galerkin method for the space variable in such a way that the global truncation error has the same order as the error for the interpolation with the Galerkin basis. Estimates are obtained for the study of the discretization that also yield an existence proof for the exact problem. Results of some numerical experiments are presented.