二阶非线性泛函微分方程解的有界性的判据

考虑二阶非线性泛函微分方程y"(t)+a(t)f(y(t))+b(t)y(t-τ)+c(t)y'(t)=0 (*)y"(t)+a(t)f(y(t))+b(t)g(y(t-τ))+c(t)y'(t)=0, (**)其中a∈C1([0,∞,(0,∞)),b∈C([0,∞),R),c∈C([0,∞),(0,∞)),f,g∈C(R,R)且存在常数λ＞0,μ＞0,使当u≠0时有u/f(u)≥λ,g2(u)≤μu2.文章得到方程(**)所有解有界的一个充分条件为,存在函数h∈C1([0,∞),(0,∞)),使得h(t)≥a't+2a(t)c(t)/b2(t),h'(t)≤0,∫∞h(s)ds＜∞.     

Mechanism Study for Thermal/Electric Field Poling of Fused Silica

On the basis of the experimental reports, the mechanism of the second-order susceptibility ⁽²⁾ for the thermal/electric field poling of fused silica is analyzed, and expressions for ⁽²⁾ are detailedly derived and numerically calculated for the first time. By comparison the theoretical value of ⁽²⁾ with the experiment results, we propose that the effective ⁽²⁾ is created via both the interaction of the intense electric field with the third-order susceptibility ⁽³⁾ and the dipole orientation. The theoretical results show that, in the differently applied voltage, the dipole orientation and ⁽³⁾ play different role in the formation of ⁽²⁾. This theory successfully explains some experiment results.     

激子自旋弛豫对简并量子点发射光子对纠缠度的影响

利用粒子数运动方程和量子回归理论，计算了单个半导体量子点双激子体系脉冲激发下粒子在各能级间辐射跃迁的二阶交叉相关函数以及系统发射光子对的偏振密度矩阵.分析了激子态能级简并量子点体系发射光子对偏振纠缠特性，讨论了纠缠度随激子态间自旋弛豫的变化关系.研究表明，激子自旋弛豫会破坏该系统发射光子对的纠缠度. 关键词： 纠缠光子对 半导体量子点 二阶相关函数     

一类二阶非线性脉冲微分方程的振动性（英）

利用Lakshmikantham等人建立的脉冲微分方程不等式研究了一类二阶脉冲常微分方程解的振动性, 获得了此类方程振动所应具备的充分条件. 同时改进了一些已知结果. 最后用一个具体例子说明了是否带有脉冲对微分方程的振动性有很大的影响.     

二阶奇异边界值问题解的存在性

在对非线性项没有附加单调性的条件下,讨论了一类二阶奇异值问题解存在的充分条件和必要条件.讨论了非线性项在t=0和t=1时的奇异性,改进了参考文献中的结果.     

教育投入与GDP动态协整关系的实证分析

运用计量经济学中的Granger因果关系检验和误差修正模型,对中国GDP的增长与教育投入之间的关系进行了实证分析,结果表明:经济增长与教育投入之间存在着明显的双向因果关系。并用误差修正模型对二者的关系进行了模拟。     

Semi-infinite programming,duality, discretization and optimality conditions†

The aim of this article is to give a survey of some basic theory of semi-infinite programming. In particular, we discuss various approaches to derivations of duality, discretization, and first- and second-order optimality conditions. Some of the surveyed results are well known while others seem to be less noticed in that area of research.     

浅谈篮球运动个人防守的控制范围

现代篮球运动竞争激烈,对抗性强性.提高运动员的防守能力,扩大其防守的控制范围,需要在防守的脚步动作、正确的选位、适时的干扰、伸缩及防守的基本姿势等方面,加强对运动员的训练与培养.     

Metrics of algebraic closures in pattern recognition problems with two nonoverlapping classes

It is shown that, in the pattern recognition problem with two nonoverlapping classes, the matrices of estimates of the object closeness are described by a metric. The transition to the algebraic closure of the model of recognizing operators of finite degree corresponds to the application of a special transformation of this metric. It is proved that the minimal degree correct algorithm can be found as a polynomial of a special form. A simple criterion for testing classification implementations is obtained.