四端光纤补偿网络的理论分析

强度干扰是阻碍强度调制光纤传感器发展及应用的关键问题.研究表明,光纤网络补偿方法对抑制强度干扰是一种行之有效的方法.作者经过深入的研究,提出了一种先进的四端光纤补偿网络结构.本文对四端光纤补偿网络进行了全面、系统的分析,揭示了网络的特性.这对于强度调制光纤传感器的发展及应用具有重要的意义.同时,对于强度调制光学测量系统也具有一定的意义.     

凝视热成像系统MTF斜缝法测试技术研究

凝视热成像系统MTF测试不同于扫描系统，必须有解决其空间采样的混淆特性。在传统的线扩展函数法基础上发展起来的方法主要有：缝扫描法、最值法、斜斜法。实际使用中，前两种方法需要精确的定位技术，而斜缝法的数据处理较复杂。本文主要论述斜缝测试法，分析其工作原理，介绍其数据处理技术。     

用频谱分析法测量声光驻波调制器的调制度

从调制的基本概念出发，指出声光驻波调制器件为宽带频率调制型。讨论了调制度概念的成立条件和适用范围。理论上求出其成立条件为ｖ＜０．９（ｖ＝２πＬ△ｕ／λ为衍射光强Ｉ（θ，ｔ）中的自变量）。鉴于一般驻波型声光器件都是含有一定的行波成份，但行波声场和驻波声场在拉曼－奈斯衍射范围内衍射角均遵从ｓｉｎθｍｉ＝土ｍλ／，故两者在空间上是无法分开的。文中给出了从频域上测量调制度Ｍ的一种新方法。并给出了零级和一般衍射光的测量值。     

Interactive effects of local smoothing window size and fundamental frequency on shimmer calculation

Slow amplitude modulation of human voice was approximated by a sinusoidal wave. The theoretical effects of smoothing window size, F₀, and modulation frequency on window amplitude average as well as calculated shimmer were mathematically derived. Subsequently, the theoretical predictions were tested using idealized and real voice signals from normal speakers. The theoretical and experimental results suggest that shimmer (when calculated using a smoothing window) is a function of window duration and modulation frequency. Window duration when defined as a constant number of pitch periods varies from speaker to speaker depending on their F₀. It may not be desirable to use local smoothing windows with a constant number of cycles for shimmer computation, especially if voices with known low-frequency amplitude modulations but notably different fundamental frequencies are compared.     

非重子冷暗物质粒子的研究进展

暗物质问题目前已受到物理学界的高度关注，因为这一课题的研究和进展，将直接影响到粒子物理、天体物理和宇宙学的发展方向。当前世界上已有一些大的实验组正在开展这方面的研究工作，并已取得了一定的结果；文章重点介绍两个重要的探测实验，即中意合作DAMA组（Dark Matter Group)100kg Nal（Tl）探测器阵列实验和美国的CDMS（Cold Dark Matter Search）实验组的低温探测器实验。详细介绍了DAMA实验的物理分析方法及其实验结果，并同CDMS实验结果进行了相应的比较。     

Optical mm-wave generation by using external modulator based on optical carrier suppression

In this paper, we have theoretically investigated the transmission performance of the optical millimeter (mm)-wave generated by using an external modulator based on optical carrier suppression for the first time. According to our theory, the data signals carried by the optical mm-wave are transmitted in the dispersion fiber without fading but are degraded greatly because of the time shift of the code edges, which still limits the transmission distance. The experimental results agree well with our theory.     

半导体激光器脉冲调制理论分析

本文用龙格-库塔法求解高斯脉冲调制下半导体激光器速率方程,对结果进行了分析。推出了较高偏置直流和高斯脉冲调制下计算激光脉冲延迟时间、脉冲宽度和最大调制码率的公式。给出了调制畸变的实验结果。     

方波调制时的光热光束偏转理论

本文叙述了加热光束光强以方波调制时的光热光束偏转理论,讨论了偏转信号值与加热光功率、光斑半径,两光点的相对位置及调制频率等的关系并与实验结果比较,其结果是定性一致的.     

The Ginzburg-Landau manifold is an attractor

Summary The Ginzburg-Landau modulation equation arises in many domains of science as a (formal) approximate equation describing the evolution of patterns through instabilities and bifurcations. Recently, for a large class of evolution PDE's in one space variable, the validity of the approximation has rigorously been established, in the following sense: Consider initial conditions of which the Fourier-transforms are scaled according to the so-calledclustered mode-distribution. Then the corresponding solutions of the “full” problem and the G-L equation remain close to each other on compact intervals of the intrinsic Ginzburg-Landau time-variable. In this paper the following complementary result is established. Consider small, but arbitrary initial conditions. The Fourier-transforms of the solutions of the “full” problem settle to clustered mode-distribution on time-scales which are rapid as compared to the time-scale of evolution of the Ginzburg-Landau equation.