一种求解虚波长路径光网络波长资源优化问题的启发式算法

本文提出了一种虚波长路径光网络的启发式路由选择算法,它可以用来解决以最小化网络所需波长数目为目标的资源优化问题.该算法应用了基于最大概率路径的选路优化策略.对一个样例网络的数值分析结果表明该算法是有效的.     

缺项幂级数的最小模与最大项(英文)

在本文中我们研究缺项幂级数的最小模与最大项间的关系，改进了Ｐ．Ｅｒｄｏｓ和Ａ．Ｊ．Ｍａｃｉｎｔｙｒｅ的结果     

成组Broyden修正矩阵的紧凑形式与成组记忆修正算法

1 引言 成组型线性方程组 其中,p是适中的数值,由于其有相当的实际应用背景,人们一直在研究有效的数值方法,特别是近年来,实际问题中归结出来的成组型方程组,其规模越来越大,又具有稀疏结构,因而使用迭代法是一种有效的途径,目前使用比较多的是Krylov子空间方法中的Lanczos方法,CG方法,GMRES方法等等。这种成组型算法的建立,其基本出发点是使算法具有较少的计算量和存储量,具体体现在: 1)成组型算法在应用于问题(1.1)的求解时,也具有有限终止性性质,而其终止步数一般要比单个型算法的步数减少了户倍,由于成组型算法每迭代一步的计算量基本上等同于单个型算法使用户次的计算量,如此,算法的计算量会有明显的改善。 2)当A存储在二级(secondary)内存时,在迭代计算时需要不断地进行存取交换,由于成组型算法的迭代步数减少了户倍,如此,用在这种交换的时间也要减少户倍,相当有效。 3)由于在成组型算法中,出现的多是AX的形式,其中,故成组型算法便于计算并行化。 4)即使用于求解单个方程组,当A的少数几个极端特征值分离甚远时,这种成组型算法也有可能改善其收敛速度,如成组型的CG方法。 目前,这种成组型算法已体现出很大的实用计算价值,然而其进一步的理论分析还有待深入研究。     

On convergence of a semi-analytical method for American option pricing

We examine the valuation of American put options by a semi-analytical method, and obtain the prior estimate and the convergence of the approximate solution. Our proofs are based on the embedding theorem in Sobolev space and the theory of functional analysis, in particular, the theory of weak compactness. The results in this paper theoretically confirm empirical observations that these methods are accurate and computationally efficient.     

Applicability of improved Rayleigh-Sommerfeld method 1 in analyzing the focusing characteristics of cylindrical microlenses

The applicability of an improved Rayleigh-Sommerfeld method 1 (IRSM1) is investigated by analyzing the focal characteristics of various cylindrical microlenses in both cases of the TE and TM polarizations. The IRSM1 and original Rayleigh-Sommerfeld method 1 (ORSM1) are compared with rigorous boundary element method (BEM) by calculating the average square-root deviation (ASRD) of the intensity distribution on the focal plane for the continuously refractive microlens and diffractive microlenses with continuously varying or 8-level quantized profiles. The results indicate that the applicability of the IRSM1 has limitation in some parametric ranges, for instance, the number of sampling points, f-number, relatively refractive index, and wavelength of the incident light are restricted to some appropriate values.     

On stability crossing curves for general systems with two delays

For the general linear scalar time-delay systems of arbitrary order with two delays, this article provides a detailed study on the stability crossing curves consisting of all the delays such that the characteristic quasipolynomial has at least one imaginary zero. The crossing set, consisting of all the frequencies corresponding to all the points in the stability crossing curves, are expressed in terms of simple inequality constraints and can be easily identified from the gain response curves of the coefficient transfer functions of the delay terms. This crossing set forms a finite number of intervals of finite length. The corresponding stability crossing curves form a series of smooth curves except at the points corresponding to multiple zeros and a number of other degenerate cases. These curves may be closed curves, open ended curves, and spiral-like curves oriented horizontally, vertically, or diagonally. The category of curves are determined by which constraints are violated at the two ends of the corresponding intervals of the crossing set. The directions in which the zeros cross the imaginary axis are explicitly expressed. An algorithm may be devised to calculate the maximum delay deviation without changing the number of right half plane zeros of the characteristic quasipolynomial (and preservation of stability as a special case).     

超高压状态方程中激光驱动冲击波稳定性

实验利用特制的斜面Al靶,在空间均匀辐照的高功率激光驱动下,研究了激波在不同厚度材料中的传播稳定性,对应于激光状态方程实验中通常所用的靶参数(主要指厚度)范围,给出了相应的测量结果.实验所获得的激波发光信号及d-t图,P-d图表明,冲击波在此范围内具有很好的传播稳定性. 关键词：     

A high average power rotating hollow cylinder Nd : glass laser

The rotating hollow cylinder glass laser is one of the approaches for the generation of high average output powers scaling to kilowatt levels from solid-state laser materials. An analytical solution of the heat conduction equation is presented for a thin wall, infinitely long glass medium, with boundary conditions given by Newton's law of cooling. The theoretical result is applied to predict thermal effects of this geometry which ultimately limit the laser performance, and the design of such a laser. A flashlamp pumped rotating Nd-doped phosphate glass hollow cylinder laser has been demonstrated. An average power output of 300 W has been achieved at 3.8% slope efficiency and 2.6% overall efficiency. Our investigation shows that the development of a kilowatt average power rotating cylinder laser is feasible.     

A new 3s–3d heterometallic polymer containing N‐methyliminodiacetic acid: synthesis,structure and characterization

A new complex {[Na₂(H₂O)₃(µ‐L)₂Cu]₄}_∞ (L = N‐methyliminodiacetic acid) has been synthesized and structurally characterized. The complex crystallizes in the monoclinic, space group C2/c, with the unit cell parameters a = 16.556(3) Å, b = 8.0622(13) Å, c = 12.671(2) Å, α = 90°, β = 95.849(2)°, γ = 90°. The central metal Cu (II) ion is coordinated with two nitrogen atoms and four oxygen atoms belonging to two ligands. Simultaneously, the sodium is six‐coordinated with oxygen atoms coming from the ligand and water molecule; the sodium atoms related are bridged by oxygen atoms, forming a sodium chain. The structure consists of CuL₂ moieties linked by sodium chain via the exo oxygen atoms of two ligands, forming a novel three‐dimensional structure. Moreover, elemental analysis, IR, UV‐vis, ESR spectroscopy and thermal stability were determined. Copyright © 2007 John Wiley & Sons, Ltd.     

波状膜层全角度偏振分束特性的分析

从能带结构和等频面两方面完整阐述了利用光子晶体实现全角度偏振分束的条件，分析等频面目的在于确保波矢的切向分量保持连续，采用时域有限差分(FDTD)方法模拟了高斯光束在波状膜层中的传播过程，通过对比TE模与TM模在0°—89°不同入射角情况下的振幅透射系数，理论上验证了波状膜层的全角度偏振分束效应. 关键词： 光子晶体 偏振分束 等频面