PERIODIC BOUNDARY VALUE PROBLEM FOR SECOND ORDER FUNCTIONAL DIFFERENTIAL EQUATIONS

This paper investigates the periodic boundary value problems for a class of second order functional differential equations. The monotone iterative technique and the maximum principle are applied to obtain the existence of maximal and minimal solutions.     

试论网络传播中的社会控制

一般来说网络传播是自由的,因为在网络中我们可以自由的传递和接收信息,但是,网络传播受到的各种控制却往往被人们忽视。本文试图从社会控制的角度,从网络传播受到的内在控制和外在控制两个方面,探讨网络自由传播的本质,以期对网络传播作出正确的评价。     

桥头跳车原因分析及质量控制

文章针对桥头跳车原因的形成 ,就解决方法从施工工艺及质量控制方面作了介绍。     

内照射小器官剂量计算中减方差技巧的比较和应用

在用人体模型计算内照射比吸收分数的Monte Carlo模拟中,对小尺寸、远距离器官的计算结果通常精度不够,可信度差,这就要求采用减方差技巧。该文采用一个简单模型比较了直接模拟和区域粒子分裂-轮盘赌、强迫碰撞与DXTRAN球、指向概率强迫碰撞3种减方差技巧的效果。结果表明指向概率强迫碰撞方法能更有效解决此类问题。利用中国人体数学模型,选择一组典型的源靶器官对,计算了一个实例,得到了可信度高的吸收分数值并体现了指向概率强迫碰撞方法的优越性。     

对网络保险发展的思考

保险网络营销已成为保险业务发展的重要推动力,网络保险的发展已被很多保险公司视为提高自身竞争力的核心要素。这种传统产业与新兴产业相互融合的过程,不仅给保险电子商务带来了新的转机,也给传统保险经营的模式增加了新的活力。     

复合顶板条件下刨煤机工作面收尾工艺研究和应用

根据马兰矿10508刨煤机工作面收尾工作的特殊性,确定了工作面收尾工艺,并根据收尾过程中出现的问题提出了改进意见。     

Stability analysis of abnormal multiplication of plankton using parameter identification technique

This paper presents the mathematical approach for the abnormal multiplication of plankton. An abnormal multiplication can be expressed as an unstable problem and the stability of the system is investigated by introducing eigenvalues of a mathematical equation. The stability of the system can be judged by an eigenvalue based on the Lyapunov's stability theory. In this paper, the Arnoldi‐QR method is used to obtain eigenvalues and eigenvectors of the system. The mode superposition method is employed to create spatial distribution needed to analyse the stability. To obtain the objective eigenvalue, the parameter identification technique is employed. The finite element method is used for the discretization in space. Lake Kasumigaura, which is located in Ibaraki Prefecture in Japan, is selected and actual data in 1975, 1976, 1991 and 2000 are used in order to investigate the stability of the specified lake in Japan. Copyright © 2004 John Wiley & Sons, Ltd.     

An embedding domain approach for a class of 2-d shape optimization problems: mathematical analysis

This contribution combines a shape optimization approach to free boundary value problems of Bernoulli type with an embedding domain technique. A theoretical framework is developed which allows to prove continuous dependence of the primal and dual variables in the resulting saddle point problems with respect to the domain. This ensures the existence of a solution of a related shape optimization problem in a sufficiently large class of admissible domains.     

营口地区公路抗盐碱栽植新技术的研究

以辽宁省营口地区作为研究实例,通过土壤全盐量的测定,对营口地区抗盐碱栽植新技术进行了分析,并对结果进行了评价。     

刨煤机工作面初采初放新工艺的研究与应用

根据马兰矿刨煤机工作面初采初放工作的特殊性,阐述了对工作面初采初放工艺的改进。