Cluster synchronization in nonlinearly coupled delayed networks of non-identical dynamic systems

In the real world, many networks show community structure, i.e., clusters of nodes, which have a high density of links within the same cluster but a lower density of links between different clusters. In this paper, nonlinearly coupled networks with community structure and non-identical nodes and with time-varying delay are considered. By applying pinning control to a fraction of network nodes, and using a suitable Lyapunov function, we obtain some new and useful synchronization criteria, which guarantee that various clusters are synchronized independently. An example is presented to show the application of the criteria obtained in this paper.     

Preparation and Characteration of UV-cured EA/MMT Nanocomposites Via In-Situ Polymerization

A long-chain surfactant, enzoylbenzyl-N,N-dimethyl-N-octadecylammonium bromide (BDOB) with a benzophenone group, was synthesized to modify the montmorillonites (MMT) for the preparation of nanocomposites via photo-induced polymerization. The BDOB-modified MMT was characterized by the fourier transform infrared spectrometer (FTIR), thermal gravimetric analyzer (TGA) and X-ray diffraction (XRD), and the results of XRD indicated that the intercalated structures of BDOB-modified MMT was obtained. The conversion of the bisphenol A epoxy diacrylate (EA) was quantified by the FTIR, and the results indicated that conversion increased with an increase in the amount of BDOB-modified MMT. The morphologies of the UV-cured EA/MMT nanocomposites prepared from this organically modified MMT were studied by means of XRD and TEM, and the results showed that all the samples contained an intercalated structure with partial exfoliated structure. The results of TGA and mechanical properties also indicated that the thermal and mechanical properties of UV-cured nanocomposites were significantly enhanced due to the presence of the long chain surfactant organically modified MMT.     

Two new eudesmane derivatives from Verbesina virginica

<正>Two new eudesmane derivatives were isolated from the leaves and flowers of Verbesina virginica,along with the known 6-O-β-E -p-coumaroyl-4α-hydroxyeudesmane(1).Their structures were determined as 6-O-β-Z-p-coumaroyl-4α-hydroxyeudesmane(2) and 6-O-α-E-p-coumaroyl-1β-4α-dihydroxyeudesmane(3) by spectroscopic methods.     

葡萄酒香气成分的仪器分析方法评述

葡萄酒香气成分的研究对葡萄酒产品的质量评价及葡萄酒产品的真伪鉴别意义重大,而香气成分的分析结果及其区分价值取决于分析方法,尤其是香气成分的萃取方法。文章综述了近几年葡萄酒香气成分分析方法的研究进展,分析了"电子鼻"等非色谱方法分析葡萄酒香气的特点,阐述了葡萄酒香气成分气相色谱分析的不同检测器方法,比较了影响葡萄酒香气色谱分析结果的不同香气成分萃取方法,并对今后该领域的研究重点进行了展望。     

半球面与半平面安排以及Linhart的一个猜测

首先给出半球面安排与半平面安排之间的一些联系，然后得到关于半平面安排的权和的一个方程.在此基础上证明了J.Linhart关于权和的一个猜测.     

籼型杂交稻米垩白性状频数分布及其与亲本的关系

研究结果表明 :籼型杂交稻米垩白面积指数为连续分布 ,分布曲线为单峰或不明显的双峰 ,在主峰与低谷之间的发生频率差别不大 ,说明杂交稻米垩白性状发生了广泛的分离 ;在大垩白 /大垩白或大垩白 /中垩白的组合中 ,其分布主峰在大垩白或中垩白处 .大垩白 /小垩白或中垩白 /小垩白的组合中 ,其分布因组合不同而异 ,但尽管主峰在无垩白处的组合中 ,大垩白或中垩白仍有相当的分布 ,而在小垩白 /小垩白的组合中 .不仅其主峰在无垩白处 ,且大、中垩白的出现频率也很低 .上述结果说明 ,提高籼型杂交稻米的外观品质必须选用双亲均属无或小垩白的品种进行组配     

关于算子迹的算术—几何平均不等式

本给出了关于两个或三个核算子的迹的几个算术－几何平均不等式。     

有向图上的动态规划

在集合论的基础上将离散的动态规划形式化,用递归函数刻划了动态规划的目标函数,并在有向图上建立了动态规划,推广了动态规划方法的应用范围。     

LOGARITHMICALLY IMPROVED REGULARITY CRITERION FOR THE 3D GENERALIZED MAGNETO-HYDRODYNAMIC EQUATIONS

This article proves the logarithmically improved Serrin's criterion for solutions of the 3D generalized magneto-hydrodynamic equations in terms of the gradient of the velocity field, which can be regarded as improvement of results in [10](Luo Y W. On the regularity of generalized MHD equations. J Math Anal Appl, 2010, 365: 806–808) and [18](Zhang Z J.Remarks on the regularity criteria for generalized MHD equations. J Math Anal Appl, 2011,375: 799–802).     

一类广义Liénard型系统解振荡的充要条件

给出了一类广义Liénard型系统(x)=p(y)k(x),(y)=-f(x,y)p(y)q(y)-g(x)h(y).解振荡的充要条件,文中的引理也有助于研究这类系统周期解的存在性.