COMPACT COUPLED LINEAR TAPERED LINE BANDPASS FILTER WITH TWO TRANSMISSION ZEROS

A new compact bandpass filter composed of two coupled linear tapered line resonators (LTLRs) is designed. The two resonators are arranged in different layers. The filter has two transmission zeros on both sides of the passband. It has small size and steep response below its passband. It is also shown that this filter has 0.6 dB low insertion loss at the centre frequency and 10.5% 3dB bandwidth. This work was supported by the Development Foundation of Shanghai Educational Committee (217608) and Shanghai Leading Academic Discipline Project (T0102).     

应用小波边缘检测技术分析荧光寿命显微像

研究了小波图象边缘检测技术在荧光寿命显微像分析中的应用，利用小波分析的多尺度特性进行了荧光寿命显微像的边缘提取，结果表明，这种方法非常有效。     

基于粒子群优化的移动机器人SLAM方法

针对传统Rao-Blackwellized粒子滤波器存在的粒子消耗问题,提出了一种基于粒子群优化的移动机器人同步定位与制图方法. 该方法在粒子重采样过程中利用粒子群优化算法获得机器人位姿的建议分布,并引入遗传算法中的交叉和变异操作对求得的粒子集进一步优化、调整. 改进后的粒子分布保持了粒子的多样性,有效提高了机器人位姿估计的一致性. 仿真结果表明,本文提出的方法与传统Rao-Blackwellized粒子滤波器相比,能有效解决粒子耗尽问题,使机器人获得更精准的定位和更准确的地图,具有可行性、实用性.      

基于CCⅡ的双二次滤波器的设计方法—替换法

用ＣＣⅡ构成的基本块替代由运放构成的相应基本电路，就能效经典的有源ＲＣ二阶滤波器转换成基于ＣＣⅡ的相应滤波电路。还给出了由ＣＣⅡ实现的单端和差动电压放大器以及由ＣＣⅡ实现的构成状态变量滤器的基本块－相加积分器。加权法器等。     

一种新的基于改进实时双通滤波器的信号数字积分方案

信号积分是重要的测试测量技术手段,本文综合论述了信号数字积分问题的提出、数字积分中面临的问题及解决方法。着重研究了信号数字积分技术的核心问题,即低频噪声造成的积分器不稳定问题。本文首先将一种改进的实时双通滤波算法应用于低频干扰消除,以解决积分器不稳定问题。其次,本文研究对比了目前多种数字积分算法的优缺点及性能,选择了目前最优的数字积分算法。将选择出的积分算法与实时双通滤波结合,保证了积分后信号幅值、相位精确不失真,并且保证了数字积分的实时性;从而为数字积分在测试测量及其它相关应用领域的推广应用奠定了基础。仿真研究表明,本文的方案具有较好的精度。     

Large eddy simulation of turbulent incompressible flows by a three‐level finite element method

The variational multiscale method provides a methodical framework for large eddy simulation of turbulent flows. In this work, a particular implementation in the form of a three‐level finite element method separating large resolved, small resolved, and unresolved scales is proposed. Residual‐free bubbles are used for the numerical approximation of the small‐scale momentum equation. A stabilizing term is added, in order to take into account the effect of the small‐scale continuity equation. This implementation guarantees the stability of the method without further provisions and offers substantial computational savings on the small‐scale level. Furthermore, it is accounted for the unresolved scales by a specific dynamic modelling procedure. The method is tested for two different turbulent flow situations. Copyright © 2005 John Wiley & Sons, Ltd.     

Experimental determination of cohesive failure properties of a photodegradable copolymer

In this paper we present a methodology to measure the material traction-separation relation for a poly(ethylene carbon monoxide) copolymer, ECO. This material exhibits a ductile-to-brittle transition when subjected to ultraviolet irradiation and undergoes a change of failure mechanism, from shear yielding to crazing, in the process. Single edge notched tension specimens of ECO irradiated for 50 h were used to generate slow-speed stable crack growth, predominantly from material crazing. Full-field measurements of the in-plane deformation around the growing crack tip were performed using the optical technique of digital image correlation. A multicamera setup was used in which simultaneous measurement of both the far-field displacement and that directly surrounding the craze was performed. The far-field results were used to obtain a value of the energy release rate supplied to the crack tip region. The near-tip results were used to extract a material traction-separation law in the regime of steady-state crack growth. A softening traction-separation relation was measured. The area under the traction-separation curve was then compared with the simultaneous far-field measurements and the agreement was very good (within 6.5%) validating the experimental methodology used.     

Integrating noisy data

Suppose the parametric form of a curve is not known, but only a set of observations. Quadrature formulae can be used to integrate a function only known from a set of data points. However, the results will be unreliable if the data contains measurement errors (noise). The method presented here fits an even degree piecewise polynomial to the data where all the data points are being used as knot points and the smoothing parameter is optimal for the indefinite integral of the curve which happens to be a smoothing spline. After the smoothing parameter has been chosen, this approach is less computationally expensive than fitting a smoothing spline and integrating.     

多环芳烃的滤纸基质室温磷光法研究

本文以芘为模型化合物,对滤纸基质室温磷光法的重原子进行选择, 并研究了影响磷光强度的因素. 在通氮气情况下,以十二烷基硫酸铊为重原子, 测定了芘、芴、萘三种多环芳烃的室温磷光.实验结果表 明: 芘、萘、芴的最低检测限分别为 1. 5ng、3. 0ng 和 3. 0ng, 相关系数均大于 0. 995, 相对标准偏差均小于 5%.     

激光防护器材和抗激光损伤薄膜

介绍激光防护滤光片、激光辐射屏蔽和抗激光损伤的光学薄膜的发展情况。