Eigenvalue and stability of singular differential delay systems

The eigenvalue and the stability of singular differential systems with delay are considered. Firstly we investigate some properties of the eigenvalue, then give the exact exponential estimation for the fundamental solution, and finally discuss the necessary and sufficient condition of uniform asymptotic stability.     

数学建模案例丛书即将问世

<正>以收集、精选国内外数学建模案例为主要内容的"数学建模案例丛书"即将问世了。下面刊登由丛书编委会主任李大潜院士撰写的总序、丛书编委会成员名单,以及作为丛书第一册《UMAP数学建模案例精选(1)》一书的前言和目录。丛书第二册《UMAP数学建模案例精选(2)》、第三册《ILAP数学建模案例精选》也将于2015年内出版。"数学建模案例丛书"总序数学作为一门研究现实世界中的空间形式与数量关系的科学,它所研究的并非真正     

Bounds and Constructions for Two‐Dimensional Variable‐Weight Optical Orthogonal Codes

Optical orthogonal codes (1D constant‐weight OOCs or 1D CWOOCs) were first introduced by Salehi as signature sequences to facilitate multiple access in optical fibre networks. In fiber optic communications, a principal drawback of 1D CWOOCs is that large bandwidth expansion is required if a big number of codewords is needed. To overcome this problem, a two‐dimensional (2D) (constant‐weight) coding was introduced. Many optimal 2D CWOOCs were obtained recently. A 2D CWOOC can only support a single QoS (quality of service) class. A 2D variable‐weight OOC (2D VWOOC) was introduced to meet multiple QoS requirements. A 2D VWOOC is a set of 0, 1 matrices with variable weight, good auto, and cross‐correlations. Little is known on the construction of optimal 2D VWOOCs. In this paper, new upper bound on the size of a 2D VWOOC is obtained, and several new infinite classes of optimal 2D VWOOCs are obtained.     

Lightcone dualities for hypersurfaces in the sphere

In this paper, we consider hypersurfaces in the unit lightlike sphere. The unit sphere can be canonically embedded in the lightcone and de Sitter space in Minkowski space. We investigate these hypersurfaces in the framework of the theory of Legendrian dualities between pseudo‐spheres in Minkowski space.     

REPRESENTATION OF ADDITIVE FUNCTIONALS AND LOCAL TIMES FOR JUMP MARKOV PROCESSES AND THEIR FUNCTIONAL LIMIT THEOREM

The representation of additive functionals and local times for jump Markov processes are obtained,The results of uniformly functional moderate deviation and their applications to birth-death processes are also presented.     

基于小波变换及布朗分形模型的纹理分割

在研究小波变换及布朗分形模型的基础上，定义了水平分维数，垂直分维数，对角分维数，并将它们作为纹理特征量来实现纹理的分割．实验结果表明，这些特征量能够很好地反映纹理特征，从而分割时不需有关图象中纹理类别的先验信息，较以往方法在准确度和计算复杂程度上都有很大提高．     

植物生长促进剂WD-5和WD-9对油菜生理和产量效应的研究

植物生长促进剂ＷＤ－５和ＷＤ－９于苗期或苗、苔期各喷施１５０ｍｇ／ｋｇ，其叶面积增大，干物质量增加，光合强度增强；苗期喷施者的ＧＡｓ和ＩＡＡ含量分别比对照高３７．４％～６１８．２％和３８．２％～１１４．４％，但ＡＢＡ含量也比对照高，因而易产生早衰现象．ＷＤ－５苗期喷施增产１０．２％，苗、苔期各喷一次增产１４．７％；ＷＤ－９苗期喷施增产１３．１％，苗、苔期各喷一次增产９．０％．     

NiMn2O4纳米粉体的相变过程和晶粒生长行为研究

采用溶胶凝胶法（Ｓｏｌ－Ｇｅｌ）制备ＮｉＭｎ２Ｏ４纳米粉体．用Ｘ射线衍射（ＸＲＤ）法，热分析仪研究ＮｉＭｎ２Ｏ４纳米粉体的相变过程．用Ｘ射线衍射线线宽法，透射电子显微镜（ＴＥＭ）研究晶粒长大行为．研究结果表明：热处理温度小于６７０°Ｃ，存在非晶晶化过程和向ＮｉＭｎ２Ｏ４尖晶石主晶相转变等相变过程，晶粒尺寸缓慢增大，热处理温度在于６７０°Ｃ，粉体的相结构为ＮｉＭｎ２Ｏ４尖晶石相．晶粒尺寸较快增长．相变过程严重影响了晶粒长大行为．