周期性点阵桁架材料力学性能分析的一种新的多尺度计算方法

论文提出一种周期性点阵桁架材料力学性能分析的新的多尺度方法.方法的主要思想是通过数值构造能反映周期性桁架材料单胞内部非均质性的多尺度基函数,从而在大尺度上求得单胞的等效刚度阵,大大减小了模型计算量.通过引入基函数的耦合附加项,以考虑多维矢量场问题不同方向问的耦合作用.数值研究表明,采用线性边界条件构造基函数有时会产生较...     

Networks Emerging from the Competition of Pullulation and Decrepitude

In real-world network evolution, the aging effect is universal. We propose a microscopic model for aging networks,which suggests that the activity of a vertex is the result of the competition of two factors: pullulatlon and decrepitude. By incorporating the pullulation factor into previous models of aging networks, both the global and individual aging effect curves in our model are single peaked, which agrees with the empirical data well. This model can generate networks with scale-free degree distribution, large clustering coefficient and small average distance when the decrepitude intensity is small and the network size not very large. The results of our model show that pullulation may be one of the most important factors affecting the structure and function of aging networks and should not be neglected at all.     

近场光学显微镜观察到纳米尺度的折射率变化

日本京都大学研究人员用近场光学显微镜(ＮＳＯＭ)在透明的聚合物膜上制作了纳米尺度的折射率图样 ,而薄膜的透明度及表面形态均未受到严重影响 .实验中用的是 3μｍ厚的聚合物薄膜 ,它是用自转镀层法在甲苯溶液中把在聚合物 (异丁烯酸甲脂ｍｅｔｈｙｌｍｅｔｈａｃｒｙｌａｔｅ)中掺杂的 3 苯基 2 ,5 诺卜拿丁 2羧酸 (3 ｐｈｅｎｙｌ 2 ,5 ｎｏｒｂｏｒｎａｄｉｅｎｅ 2 ｃａｒｂｏｘｙｌｉｃａｃｉｄ)镀到盖板玻璃片上而成的 .折射率图样是用照明模式ＮＳＯＭ设备制作的 ,该设备具有一个剪切力尖端取样距离调节功能 ,以及一个锥形探…     

在离散多尺度分析框架下的数据分解和回复的数值特征(英)

本文在离散多尺度分析框架了讨论了关于给定数据的分解和回复过程的数值特征．它给出了数据分解和回复算法的一般设计原则，它能有效地解释在正交小波基和双正交小波基下的数据分解回复过程．据此设计原则，文中还给出了一种新的数据分解回复方法，它可以在线性分层基背景下得到解释．     

凸几何经典不等式的蕴含关系

该文指出了凸几何分析中几个具有较高应用价值的经典不等式之间的蕴涵关系.     

小周期型复合材料稳态热传导问题的一种双尺度渐近展开收敛性分析

给出一类具有某种对称性小周期复合材料稳态热传导问题解的渐近表示方法.区别于传统多尺度计算方法,将计算过程中需要求解的关于单胞Q的H_per¹(Q)周期边值问题改为齐次边值问题,这样数值方法求解时协调元空间容易构造;另一方面传统的多尺度渐近解不满足原始问题的边界条件,新构造的渐近形式不仅满足原始问题的物理边界条件,同时保持一定的收敛阶,更能被工程上所接受.     

DFP变尺度法与FR共轭梯度法的二次等价性

研究了求解无约束极值问题的DFP变尺度法和FR共轭梯度法的关系问题.证明了在应用于求解二次函数的极值问题时,若将初始尺度矩阵取为单位矩阵,二者实际上是等价的,即两种方法求出的极小化点列是相同的.     

Cauchy Problem for Quasilinear Hyperbolic Systemsd with Higher Order Dissipative Terms

In this paper,the author studies the global existence,singularities and life span of smooth solutions of the Cauchy problem for a class of quasilinear hyperbolic systems with higher order dissipative terms and gives their applications to nonlinear wave equations with higher order dissipative terms.     

Frequencies-Selected Enhancement of the Extended High-Order Harmonic Generation Plateau from a United Two-Atom System Irradiated by a Combined Pulse

We present a high-order harmonic generation (HHG) spectrum from a united two-atom system exposed to a combined laser pulse, by numerically solving a one-dimensional time-dependent Schr6dinger equation. The combined laser pulse is composed of a low-frequency femtosecond pulse and a high-frequency attosecond one with respective appropriate amplitudes. For a suitable inter-nuclear separation, the harmonic emission efficiencies near the second cutoff of the extended plateau can be effectively enhanced by more than four orders of magnitude compared with the case of the low-frequency pulse alone. Such a combined pulse irradiating on the united twoatom system ionizes each atom, in a large rate (but not to a too large ionization yield), mainly at a particular time-interval. When the ionized electron from an atom reaches at the vicinity of the other atom and recombines with it, significant HHG enhancement is achieved for particular harmonics. This result, to our knowledge, is one of the best up to now in the endeavor for dramatically extending the width and simultaneously enhancing the height of the plateau.     

含有各阶导数的高阶微分方程边值问题三个单调正解的存在性

利用五个泛函的不动点定理,研究一类含有各阶导数的2m阶微分方程边值问题的三个单调正解的存在性.