准一维体系的电子关联函数

对于具有库仑相互作用的准一维电子体系,本文根据电子气的集体振荡行为给出了该体系的多体波函数,并由此求出了准一维体系的电子关联函数g(|z₁₂|)。 关键词：     

市场竞争与国有企业所有权安排

改进了张维迎对地区间竞争与国有企业民营化的分析,给出了经营者的剩余索取份额对竞争性的连续依赖关系:国有企业若要降低成本,就必须参与市场竞争,随着市场竞争的加强,国有企业经营者的剩余索取份额应该逐渐增大,而当市场竞争水平超过某一阈值,国有企业经营者拥有全部剩余索取权是最优的.     

无催化纳米氧化锌的制备及其光学性质研究

本文采用无催化剂直接蒸发高纯Zn粉,在800℃氧气氛条件下,在Si(111)衬底上生长得到以四角状为主的纳米ZnO(T-ZnO)。T-ZnO纳米线每个角约互成110°,长度约为1.5μm,直径100nm左右;Raman分析表明E2(H)普遍存在于各形态的ZnO;光致发光光谱表明,T-ZnO纳米线的光致发光除了与材料性质有关,还与杂质缺陷有关,蓝绿光带是ZnO的缺陷产生的。     

位移和速度反馈的数学模型及实现方法

本文提出了位移和速度同时反馈的数学模型 .并给出了位移和速度反馈的实现方法 ,该方法用传统的差动变压器实现了位移和速度的同时反馈     

Spectral Representation Theory for Dielectric Behavior of Nonspherical Cell Suspensions

Recent experiments revealed that the dielectric dispersion spectrum of fission yeast cells in a suspension was mainly composed of two sub-dispersions. The low-frequency sub-dispersion depended on the cell length, while the high-frequency one was independent of it. The cell shape effect was simulated by an ellipsoidal cell model but the comparison between theory and experiment was far from being satisfactory. Prompted by the discrepancy, we proposed the use of spectral representation to analyze more realistic cell models. We adopted a shell-spheroidal model to analyze the effects of the cell membrane. It is found that the dielectric property of the cell membrane has only a minor effect on the dispersion magnitude ratio and the characteristic frequency ratio. We further included the effect of rotation of dipole induced by an external electric field, and solved the dipole-rotation spheroidal model in the spectral representation.Good agreement between theory and experiment has been obtained.     

BEPCⅡ高频发射机和环流器的调整和测试

北京正负电子对撞机升级改造工程(BEPCⅡ)将采用的频率500MHz、输出功率250kW的高频发射机和环流器已安装、调整、测试和验收完毕,这是国内建立的第一套500MHz/250kW发射机系统.本文将详细介绍机器的调测试的原理和各项测量内容及结果, 并比较设计指标和要求,来阐述此发射机的实际技术指标和测试性能.     

双电极对双脉冲激光器结构分析

本文对双电极对双脉冲激光器的谐振腔结构进行了分析,结果表明采用双非稳腔和增大反射镜的曲率半径可分别获得单纵模和基横模输出。为使输出能量稳定,则双电极对的间距有一最小值的限制。     

一个基于运输规模经济的库存选址模型

介绍了一种新的配送中心(DC)选址模型,在该模型中考虑了一般库存和安全库存成本,同时把从供应商到DC的运输成本也结合进去综合考虑,运输成本是由固定成本加可变成本两部分组成,反映了运输规模经济.     

Topological Properties of Urban Public Traffic Networks in Chinese Top-Ten Biggest Cities

We investigate the topological characteristics of complex networks as exemplified by the urban public traffic network （UPTN） in Chinese top-ten biggest cities. It is found that the UPTNs have small world behaviour, by the examination of their topological parameters. The quantitative analysis of the transport efficiency of the UPTNs reveals their higher local efficiency El and lower global efficiency Eg, which coincide well with the status quo of those Chinese cities still at their developing stage. Furthermore, the topological properties of efficiency in the UPTNs are also examined, and the findings indicate that, on the one hand, the UPTNs show robustness to random attacks and frangibility to malicious attacks on a global scale; on the other hand, the interrelation between UPTN efficiency and network motifs deserves our attention. The motifs which interrelate the UPTN efficiency are always triangular-formed patterns, e.g. motifs ID 238, ID 174 and ID 102, etc.     

两点拉伸型不动点定理及其应用

在研究各种非线性方程解的存在性问题时,上下解方法是一个强有力的工具.设 E是 Banach 空间,P 是 E 中的锥,E 中的半序由 P 导出.设 A:E→E 是一个算子.如果x_0∈E 满足