ARMA噪声中的正弦波检测

本文提出一种ＡＲＭＡ噪声中正弦波检测的方法，本方法先用改进的Ｐｒｏｎｙ法估计可能存在的正弦波，然后利用一种综合考虑衰减因子以及ＭＵＳＩＣ值的准则从估计结果中区分正统率波的真伪。数值例子表明，本文方法比Ｐｒｏｎｇ方法及ＭＵＳＩＣ方法具有更高的分辨力。     

PWM整流器高功率因数的实现

论述了交流斩波电路中控制部分的工作原理，并对该电路中电抗器的取值进行了计算。采用16位80C196KC单片机能使控制电路非常简单，并容易实现高频开关器件整流器的高功率因数。     

全面实施上海城市总体规划加快建设资源节约型城市

上海是一个经济快速发展的城市,同时也是一个资源相对匮乏的地区.文章从上海城市的总体规划出发,全面阐述坚持科学发展观,以资源节约型城市规划的理念,充分发挥城市规划的先导和调控作用,从全局和战略高度,实现能源、资源的合理节约利用,促进人与自然的和谐发展.     

Chalcogenide Glasses Based on Germanium Disulfide for Second Harmonic Generation

High second‐order susceptibilities are created by thermal poling in bulk germanium disulfide based chalcogenide glasses. Experimental conditions of the poling treatment (temperature, voltage, time) were optimized for each glass composition. The second‐order nonlinear signals were recorded by using the Maker fringes experiment and a second‐order coefficient χ⁽²⁾ up to 8 pm V^–1 was measured in the Ge₂₅Sb₁₀S₆₅ glass. This value is obtained using a simulation based on accurate knowledge of the thickness of the nonlinear layer. Two mechanisms are proposed to explain the creation of a nonlinear layer under the anode: the formation and the migration of charged defects towards the anode may mainly occur in Ge₂₀Ga₅Sb₁₀S₆₅ and Ge₂₅Ga₅S₇₀ glasses, whereas the migration of Na⁺ ions towards the cathode may be responsible for the accumulation of negative charges under the anode in Ge₃₃S₆₇ and Ge₂₅Sb₁₀S₆₅ glasses. Different electronic conductivity behaviors seem to be at the origin of the phenomenon. In parallel, the potential effect of the poling treatment on the structural and electronic properties is studied using Raman spectroscopy and secondary ion mass spectroscopy measurements.     

劈刀和肋环夹持工况对超声键合换能系统电学特性的影响

通过实验分析了肋环夹持松紧度和劈刀存在两个因素对超声键合换能系统电学导纳特性的影响规律。对换能系统在悬挂有无劈刀和夹持8个松紧度等各个情况下进行谐振频率附近的导纳圆测量,确定换能系统等效电路各特征参数的变化情况。由实验结果的分析可知,劈刀的附加质量以及肋环松紧程度对换能系统谐振频率的影响不大,但劈刀的存在改变了换能系统的能量分布和耗散,是影响换能系统各特征参量的主要因素之一。这些结论有助于超声键合换能系统的优化。     

一种基于循环小波累积量的谐波恢复方法

循环统计量是乘性和加性噪声中谐波恢复问题的主要分析工具之一。本文在其基础上提出了一种新的理论与方法——基于循环小波累积量的谐波恢复方法。首先,提出了循环小波累积量的定义。然后,建立了基于一阶、二阶、三阶循环小波累积量的谐波分量的频率和相位的估计方法。在此基础上,采用了一种可调参数的小波,通过调节其参数来改善传统方法中频率分辨率低的缺陷。最后给出了模拟实验结果。     

Optically Tunable Nonlinearities in Polymers Based on Photoisomerizable Metal‐Based Coordination Complexes

The bottom‐up design of polymer films exhibiting quadratic nonlinear optical properties that can be tuned optically and chemically is described. The polymer matrices are doped with metal‐containing chromophores built around a Zn^II core and photoisomerizable ligands with two different geometries. These molecules possess specifically designed photophysical and nonlinear optical properties to be used towards all‐optical poling, an interference process between one‐ and two‐photon excitations that locally induces macroscopic second‐order effects in polymer films. It is shown that grafting the molecules onto the polymer chains improves the stability of the macroscopic photoinduced nonlinearity in the films.     

弹性直杆热膨胀状态下的非线性振动

以ＫＢＭ法为基础，引进谐波平衡观点来研究弹性直杆热膨胀状态下的非线性振动．通过实例计算表明，弹性直杆热膨胀状态下非线性振动的频率对温度的变化非常敏感．     

光纤中二次谐波的产生及机理的电镜分析

本文报导了石英光纤中的二次谐波产生及用透射电子显微镜观察光纤内部物质结构变化的实验结果,观察到了已“预置”光纤中缺陷的存在.     

量子卡诺制冷机制冷率与熵产率的协调优化性能

研究了内可逆谐振子量子卡诺制冷机的整体最优性能。得到了协调优化目标函数Ｅ最大时量子制冷机的制冷系数以及最佳制冷率和熵产率。