全光纤反射式马赫曾德尔干涉型多波长滤波器的研究

对反射式的马赫－曾德尔干涉型多波长滤波器的性能作了较详细的研究，得出了两个耦合器的分光比和两臂的臂长差对其输出谱线的影响，结论对设计制作不同性能指标的该型多波长滤波器具有重要的参考价值。实验上用光纤熔融拉锥法制作了该种器件，实验结果与理论相符合。     

一种新型可调谐锁模光纤激光器

利用法布里-珀罗腔的激光二极管作为调制器件，实现环形腔光纤激光器的主动锁模。并利用法布里-珀罗腔的激光二极管的多纵模特性，把激光二极管当作一梳状滤波器，通过偏振控制器来调整入射到激光二极管内光的偏振态，同时均衡腔内增益，得到波长大范围可调谐的锁模激光，其脉冲宽度约为48ps，脉冲重复速率2GHz。     

纳米MOSFET迁移率解析模型

从玻尔兹曼方程出发，重新计算了纳米MOSFET沟道内的载流子所服从的分布函数，特别是考虑了纳米MOSFET横向电场和纵向电场之间的相互作用，并且以得到的非平衡状态下的分布函数为基础，考虑载流子寿命和速度的统计分布，给出了纳米MOSFET载流子迁移率的解析表达式.通过与数值模拟结果进行比较和分析，该迁移率解析模型形式简洁、物理概念清晰，且具有相当精度. 关键词： 玻尔兹曼方程 纳米MOSFET 迁移率 沟道有效电场     

MEMS光开关及其与光纤组装方式的研究

光开关是一种在光路中应用极其广泛的光无源器件,可用于扫描、投影、通讯等多种不同的领域,其中用于全光通讯中连接光纤之间的光开关日渐成为人们关注的焦点.高性能、低成本、又能大量生产的MEMS光开关很好地满足了全光网络对器件的要求.本文对这种MEMS光纤光开关的类型、特点以及研究现状进行了介绍,并给出了MEMS光开关与输入输出光纤的组装与自组装以及主要方式.     

基因芯片荧光图象采集与分析

描述了基因芯片荧光图象的光学共聚焦成象,大范围高速扫描与控制,数据采集的原理和方法.并讨论了基因芯片荧光图象的分析算法,即模板定位与阈值分割相结合的半自动算法,并将其计算结果与完全采用人工分割算法的结果进行了比较.     

On Dirichlet Characters of Polynomials

The main purpose of this paper is to use the properties of Gaussiansums and the analytic method to study the problem of calculatingone kind of character sums modulo q, and to give an interestingidentity. 2000 Mathematics Subject Classification 11L10, 11L40.     

具连续时滞Liénard方程概周期解的存在唯一性

结合Liapunov泛函，研究了具连续时滞Lienard方程概周期解的存在唯一性和安全一致渐进稳定性。     

Analysis on the effectiveness of the 20-H rule for printed-circuit-board layout to reduce edge-radiated coupling

This paper presents the quantified study of the electromagnetic radiation mechanism of the 20-H rule using a numerical approach that has not yet been systematically addressed. The 20-H rule is a rule-of-thumb layout technique recommended to minimize radiated fields propagating from the edges of a printed circuit board (PCB) coupling onto nearby structures. Propagating electromagnetic fields may corrupt adjacent cable assemblies, sheet metal enclosures, and aperture openings. The magnitude of this design rule is investigated using the full-wave finite-difference time-domain (FDTD) method. An analysis on whether benefits exist from use of this rule is examined and under what conditions the rule is valid when correctly implemented. The purpose of this paper is to provide insight into the validity of the 20-H rule, recognizing that every PCB will have different simulation results. FDTD is used to capture a snapshot view of field propagation. This view allows one to determine the validity of the 20-H rule at a single point of time within a dynamic structure and what may be expected when digital components are finally added to a PCB assembly, which generally negates simulated results.     

Optimal sequences and sum capacity of symbol asynchronous CDMA systems

The optimal signature sequences that maximize the sum capacity of a direct sequence code-division multiple-access (CDMA) system are characterized in the general case of symbol delay profile and user power constraints. It is shown that the optimal sum capacity of the symbol asynchronous system equals that of the symbol synchronous system with the same user power constraints. With the optimal signature sequence set, the maximum sum capacity is achieved with white Gaussian input signals. The existence of the optimal signature sequence set is proved by the proposal of an explicit construction method for arbitrary user delay profiles and power constraints.     

两个安全第一思想模型的比较分析

针对投资者可能的投资需求确立了基于安全第一思想下两个相近的投资目标:1、极大化投资末期总收益率超过给定水平α的概率;2、极小化投资末期总收益率与给定水平α的距离.并分别就这两个目标建立了优化决策模型,得到了模型解析解,最后对两个模型结果进行了比较分析和经济解释.