非对易相空间三模坐标动量耦合谐振子的能谱

本文用不变本征算符方法研究非对易相空间中三模坐标动量耦合谐振子的能谱,分别得到了非耦合和坐标动量耦合两种情况下谐振子能谱的解析解,其中包括受非对易参数θ和φ影响的解λ0,1和λ1,1,以及不受非对易参数θ和φ影响的解λ0,2和λ1,2.然后,分析了两类耦合参数κ和η对三模坐标动量耦合谐振子能谱的影响.结果发现,耦合参数κ和η对λ1,1的影响是相同的,且当κ=η时,耦合系数κ和η对λ1,1是没有影响的.     

相对论中的若干“勾股定理”

本文总结了作者讲授电动力学与狭义相对论的若干心得与体会;运用四维闵可夫斯基空间张量的性质及其缩并运算法则,介绍了用各阶四维张量构造相对论不变量即四维标量的方法,进而在所得四维标量为负定的类时标量时,推导出若干典型的勾股关系,并应用或验证于若干简单情形.     

Holographic Storage Properties of In：Fe：Mn：LiNbO3 Crystals

In:Fe:Mn:LiNbO3(LN) crystals were grown in air atmosphere by Czochralski method with different concentration of In (0,1,2,3 mol%) in the melts,while the contents of Fe2O3 and MnO were 0.1 and 0.5 mol%,respectively. The location of doping ions was analyzed by Ultraviolet-visible absorption spectra and differential thermal analysis. The diffraction efficiency (η),writing time (τw) and erasure time (τe) of the crystals were measured by two-beam coupling experiment. The dynamic range and photorefractive sensitivity have also been calculated. The results showed that with the increase of In ions in the melt,the absorption edge of In:Fe:Mn:LN crystal shifts to the violet firstly and then makes the Einstein shift,the Curie temperature of crystal increases firstly and then decreases,the storage ratio speeds up,diffraction efficiency decreases,and dynamic range and photorefractive sensitivity increase. The mechanism of holographic storage properties of In:Fe: Mn:LN crystal with different doping concentration of In3+ was investigated,suggesting the In: Fe:Mn:LN crystals are excellent holographic storage materiel with better synthetical properties than Fe:Mn:LN crystals.     

一种在非视距环境中的移动节点定位方法

在移动节点射频定位技术基础上,根据自主移动节点运动的特点,提出一种能够减轻非视距NLOS影响的定位算法nLAEL．该算法首先利用移动节点的速度信息,构造相对定位轨迹;然后通过相对定位轨迹和射频定位的比较实现对位置和方向的估计,获取定位结果;最后估计射频定位精度,区分出失真的射频定位结果,以减小NLOS的影响．本算法计算简单,是一种实用的移动节点定住方法．仿真实验结果证明了算法的有效性．     

大型柔性结构振动主动控制的实验研究

本文采用压电陶瓷作为传感器和执行器,对二维柔性板的振动抑制进行了实验研究。指出了在实际系统中采用同位控制存在的问题,并提出了改进的方法,对二维柔性板的振动抑制实验。证实了同位控制的问题,验证了改进方法的有效性。     

航天器管路吹除污染物成分分析与来源解析

制定了航天器管路吹除污染物检测总体技术方案,并依据方案分别采用扫描电镜能谱检测技术、衰减全反射傅立叶红外光谱检测技术和液相色谱-质谱联用检测技术,对航天器产品在管路吹除过程中发现的黄色污染物液体进行了成分分析,结果表明,航天器管路吹除污染物的主要成分为苯酚类物质和油脂类物质,污染物来源于航天器生产加工工艺过程中使用的润...     

离散设施选址问题研究综述

本文首先回顾了设施选址问题百年发展历史,认为其研究经历了零散研究、系统研究、不确定性研究三个阶段.离散选址问题包括中值问题、覆盖问题、中心问题、多产品问题、动态问题、多目标问题、路径选址问题、网络中心选址问题8个子问题.最后作者讨论了选址问题研究中存在的问题以及今后发展的趋势.     

A duopolistic spatial competition model with non-zero conjectural variation

Consider a two-stage non-cooperative Cournot game with location choice involving two firms. There aren spatially separated markets located at the vertices of a network. Each firm, first selects the location of a facility and then selects the quantities to supply to the markets in order to maximize its profit. Non-zero conjectural variation at the second stage is studied. Equilibrium in the quantities offered by each firm in the markets exists. Furthermore, when the demand in each market is sufficiently large, each firm chooses to locate its facility at the vertices. Partially financed by FEDER and Ministerio de Ciencia y Tecnología, grant BFM2002-04525-C02-01, and Universidad de Las Palmas de Gran Canaria, grant UNI2004/12     

Toward Optimal ε-Approximate Nearest Neighbor Algorithms

We combine the recent optimal predecessor algorithm with a recent randomized stratified tree algorithm for an ε-approximate nearest neighbor to give an algorithm for an ε-approximate nearest neighbor in a fixed-dimensional space that is optimal with respect to universe size. We also give a deterministic version of the stratified tree algorithm.     

两个方差分量的不变二次估计的可容许性

本文对Ｙ￣Ｎ（Ｘβ，θ１Ｖ１＋θ２Ｖ２），Ｖ１，Ｖ２〉０给出了方差分量的线性函数的不变二次无偏估计、不变二次非负估计及不变二次估计不可容许的充要条件，并据此给出了具体判别上述估计的可容许性的方法。