柔性输流管泄流效应实验研究

基于模型试验研究了柔性输流管在恒定内流速度下由泄漏孔引入的泄流效应.研究发现:泄流效应可改变临界值,使得形变随流速增大近似线性增大;增加管道失稳时的形变幅值,可激发不同输流管的系统模态,引起管道多个频率的振动响应.研究结果为管道运输泄漏点定位提供了支撑,为数值模拟提供了实验参照.     

气体储罐泄漏扩散模型研究

安全评价中如何预测和模拟气体储罐完全破裂后介质在瞬间泄漏的动态扩散过程目前还没有合适的模型,通常只能借用环保领域中的高斯模型和Su tton模型,但环保领域的模型为稳态扩散模型,不含时间变量,并不适合动态扩散过程.目前开发的用有限元方法求解的计算机模型只能针对具体的装置进行模拟.本文根据F ick定律建立了气体扩散的动态模型,再限定气体储罐形状为最常见的圆柱形,确定了模型的初始条件和边界条件.通过坐标变换和两个积分变换:Fourier变换和适用于圆柱函数(Bessel函数)的H ankel变换,求出了此条件下扩散方程的解析解.     

铀包装容器含水量计算分析

以铀材料腐蚀理论、Henry定律、渗透与泄漏理论为基础,建立了铀包装容器的含水量理论计算方法,分析了铀包装容器在不同状态下的水分含量及其变化规律.结果表明,水分的泄漏量、渗透量和泄漏渗透处两端的压力差成正比,渗透与材料本身的渗透系数有关;有机材料吸附水不仅与材料自身的饱和含水率有关,而且和有机材料所处的水分分压有关;铀水反应消耗水量与铀材料质量、表面积及时间成正比.水分的渗透、环境湿度及有机材料吸附水是影响铀包装容器中水分的主要因素.     

弹性介质中充液井孔的漏模和井孔声场中的分波计算

在对井孔中与声场有关的不同Riemann叶上的复极点(泄漏模式)分析的基础上研究了纵波头波和其它分波的分离和计算问题,分析了现行的头波理论的缺陷,指出了泄漏模对横波头波和在高Poisson比地层中的纵波头波的贡献不能忽略,同时提出了正确的分离和计算纵波头波和其它分波的方法,改进了现行的声波测井理论.     

装载与运输路径的联合最优规划

运输问题中可以分为两个过程:分配装载和规划路径运输,后者是图论问题,前者因为涉及到分配不同的货物装载到不同的运输工具上,是非线性整数规划问题,所以整个问题也是NP复杂问题,随着问题复杂度的增加,变量增多,求解将会非常耗时和困难.提出了基于多旅行商的M-TSP图论装载运输优化模型,和对此模型进行简化后的基于确定路线的整数线性规划装载模型,从而极大的方便此类问题的快速求解,为实际生产运输商业行为提供了一种方便、科学、可靠的决策模型和方案.     

随机规划在专用码头管理与设计中的应用

<正> 所谓专用码头,就是只向船中装载或只从船里卸下固定的有限几种货物的码头.其货物由火车、汽车等运输工具运到或运出码头.如煤码头,油码头,矿物码头,盐码头,散粮码头等.在这类专用码头的管理与设计中常常提出下述问题.对于正在使用中的专用码头,经常遇到:问题 PA.在满足船、车在港停留时间等技术条件下,如何利用现有装卸设备、货场,选用何种调度原则,使码头的年吞吐量最大?问题 PB.在完成一定的年吞吐量的前提下,如何利用现有装卸设备、货场,选用何     

在时间尺度上研究带有脉冲的泄漏时滞细胞神经网络反周期解的动态特征

在时间尺度上,通过使用叠合度理论中的连续定理和微分不等式技巧,研究带有脉冲的时变泄漏时滞细胞神经网络模型的反周期解,获得了一些使带有脉冲的时变泄漏时滞细胞神经网络模型的反周期解存在和全局指数稳定的充分条件,并将以前的结论在时间尺度上做了扩展.     

考虑气体加速效应的高压气井产能方程推导及其应用

高压气体径向渗流中气体加速效应非常显著,因此传统二项式或三项式产能方程中的非Darcy项不能反映带有气体加速效应的非Darcy渗流特征.气体加速效应影响的忽略导致无阻流量计算的误差增大,不利于合理产能和开发方案的确定.采用考虑了气体加速效应的高压气体运动方程,通过质量守恒方程、真实气体状态方程和气体运动方程,推出考虑加速效应的高压气井产能新方程,此方程同样可反映传统的二项式产能方程,提高了无阻流量的预测精度.由于此方程没有解析解,采用类比法进行简化,再利用试凑法,求解此产能方程的相关系数.为了验证准确性,将该方程应用到了四川盆地高压气藏西35⁃1井的试井资料中,其解释结果与陈春燕和罗银富等所得结果进行对比分析,结果表明该方法所获得的产能精度明显提高,并且能够消除随着压差增大而产能相对误差增大的弊端,更加有利于高压气井无阻流量的精确计算.研究结果丰富了高压气井产能预测方法,同时无阻流量的准确计算保障了高压气井合理产能的确定.     

具有泄漏时滞的复值神经网络的全局同步性

研究了一类具有泄漏时滞的复值神经网络的全局同步性问题.在不要求激励函数可分离为实部函数和虚部函数的条件下,通过构造合适的Lyapunov-Krasovskii泛函,并运用驱动-响应同步方法、自由权矩阵方法和矩阵不等式技巧,获得了具有泄漏时滞的复值神经网络全局同步性的充分条件和同步控制器设计方法.给出的判据是由复值线性矩阵不等式表示的,易于MATLAB软件的YALMIP Toolbox实现.数值仿真实例验证了获得结果的有效性.     

考虑冗余的极小碰集问题研究

针对海上采油平台可燃气体探测器布设优化问题，首先建立了一个精确理论模型；通过对精确理论模型进行降维、简化和数字化处理，得到一个近似应用模型，该模型可视为极小碰集问题的一个变体，即考虑冗余的极小碰集问题。证明了冗余度大于或等于2的极小碰集问题都是NP-完备的。结合探测器布设的应用背景，针对冗余度为2的问题设计了一个启发式算法，旨在保证冗余度的前提下，极小化所需探测器的数目。仿真结果表明，该算法可以在不显著增加或减少探测器安装数目的情况下，使得任何一个拟泄漏点在任何风向下发生泄漏，都可以至少被两个探测器探测到，从而大大提高平台的安全性。     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

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Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].