Improved phase performance for rotman lens

Rotman lenses are used to obtain multiple beams from a single array. Although the beams produced by the feed antennas at focal points have no path length errors, the beams produced by feed antennas at off focal points may have large path length errors. These path length errors cause deterioration in the multiple beams. In this article, two novel methods are introduced to obtain feed curves which reduce the path length errors of off focal feed points significantly, compared with the commonly used circular and elliptical feed curves. The first method obtains feed curve points based on having zero path length error at three chosen points of the radiating array for each beam direction. The second method uses the particle swarm optimization method for obtaining optimum feed points for each beam direction. The results show that there is a very significant drop in the level of the maximum path length errors (in the order of about 1:4). © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 23: 634–638, 2013.     

永磁同步电机模糊PID控制建模与仿真

永磁同步电机（PMSM）作为一种非线性、强耦合、参数时变的被控对象,传统PID对其控制效果欠佳。为此在PID的基础上,结合模糊控制的优点,设计了一种PMSM的模糊自适应PID控制策略,并对系统建模仿真。结果表明,与PID控制相比,该模糊PID控制方案具有自适应强、超调量小等特点。     

基于瞬变电磁法的电磁场矿藏解释仿真技术研究

将瞬变电磁法（Transient Electromagnetic Method,TEM）应用到布敦花铜矿矿区的解释中,首先需建立电磁感应模型,对瞬变电磁场中的二次磁场频率、时间特性进行分析,通过MATLAB软件进行程序编写,得出相应的特性曲线图。然后分别计算早、晚期视电阻率和全程视电阻率,得出瞬变电磁场在矿区变化时的视电阻率参数变化,得出相应的数据结论。最后,利用MATLAB的网格化函数,对数据进行处理,模拟出瞬变电磁场在铜区时的异常场变化,完成对矿区的解释。从结果分析可以看出,利用瞬变电磁法解释的结果比利用物探资料进行矿区解释的结果更简单、更精确。这样一来,既提高了工作效率,又提高了解释的准确率。     

基于迈克尔逊干涉仪的SPR传感器的研究

研究了一种基于迈克尔逊干涉仪干涉成像的新型表面等离子体共振(Surface Plasmon Resonance,SPR)传感器,介绍了系统的构建方法和工作原理。系统以溴钨灯为迈克尔逊干涉仪的光源产生干涉图像,采用Kreschmann棱镜耦合结构激励SPR,由CCD摄像机采集传感芯片干涉图,对干涉图进行信息提取和傅里叶变换得到光谱图,再对光谱图进行分析处理得到SPR曲线。在系统中引入了辅助定标光路,即以一已知波长的单色光(氦氖激光器)作为标尺确定光强随光程差变化的干涉图函数中采样点的选取,降低了使用迈克尔逊干涉仪过程中的转动和传动机械误差。实验结果表明,该传感系统具有成本低、结构简单、操作方便、多通道检测等优点。     

基于ANSYS软件分析的磁通量传感器设计

设计用于在线监测的磁通量传感器,通过分析传感器磁路用磁导法计算磁通量传感器的具体参数。由ANSYS仿真软件建立磁通量传感器的模型。选用通用标示法（GSP）通过求解器对模型进行运算,模拟磁通量传感器的磁场分布,得到缆索中磁通量分布图以及相关数据。根据仿真结果对套筒式磁通量传感器和单旁路式磁通量传感器作出对比分析,并研究缆索外层护套对缆索导磁效果的影响。     

Using electric actuation and detection of oscillations in microcantilevers for pressure measurements

Response characteristics of a microcantilever, such as resonant frequency, amplitude, phase and quality factor, can be used for absolute pressure measurements in the range of 10⁻⁴ to 10³ Torr. To this end, it would be very convenient to have the resonance of the microcantilever actuated and detected electrostatically. Herein, we report the nonlinear dynamics of microcantilevers under varying pressure and different gases using the harmonic detection of resonance (HDR) technique [J. Gaillard, M.J. Skove, R. Ciocan, A.M. Rao, Electrical detection of oscillations in 340 microcantilevers and nanocantilevers, Rev. Sci. Instrum. 77 (2006) 073907]. The HDR technique exploits nonlinearities in the cantilever-counter electrode system to allow electrostatic actuation and detection of the responses of the microcantilever to the pressure and gas composition. In particular, the 2nd and 3rd harmonics of the measured charge on the cantilever are investigated. The microcantilever demonstrates a quality factor of 10,000 at 10⁻³ Torr, and a usable response in the range from 10⁻³ to 10³ Torr. The use of different harmonics can enable us to adjust the range of pressures over which the sensor has an efficacious response, enhancing its sensitivity to a particular environment. The experimental results are in reasonable agreement with theoretical calculations, despite the nonlinearities involved.     

Signal enhancement of surface plasmon resonance-based immunoassays for the allergen detection

A surface plasmon resonance (SPR) biosensor was used to determine the recombinant group 1 house dust mite allergen (rDer f1) in both HBS-EP buffer and fetal bovine serum (FBS). The monoclonal antibody was immobilized onto the CM5 sensor chip surface using an amine coupling method. The procedures of antibody immobilization and the subsequent primary and enhanced immunoassay were monitored in real time. The sensitivity for rDer f1 detection was remarkably improved by using intact polyclonal antibody as signal amplifying agent. Using this signal enhanced SPR immunosensor, rDer f1 in HBS-EP buffer and FBS was detected at a concentration of 15.4 and 32.1 ng/ml, respectively. The result demonstrates that SPR biosensor is a simple and reliable method for allergen detection.     

开卷机钢卷直径计算优化算法在带钢纵剪生产线中的应用

在带钢纵剪生产线的电气控制系统中,开卷机的钢卷卷径（以下简称卷径）是一个重要的检测参数,其检测和计算的准确性对系统的控制精度影响很大。本文介绍了一种适用于纵剪生产线开卷卷径的测量与计算方法,并且简要说明了如何通过西门子S7-400PLC来实现。经过实际的生产运行证明,该方法可以提高开卷机的实际卷径精度,增强测控系统的稳定性和可靠性。     

一种新型的磁定向系统及其定向算法研究

为了提高基于地磁检测的定向精度,通过引入高精度步进电机控制,设计了一种新型的平面单轴磁定向系统。该系统仅需要一个磁性传感器输出信号,通过步进电机带动磁传感器在水平面内做等间隔转动,求取最大值位置以确定磁方位。针对干扰和测试噪声的影响,研究了基于遗传算法和最优化理论的混合数据处理方法。通过对测试数据正弦曲线的四参数拟合,获取初始相位,提高了测角精度。仿真研究和工程实验表明：该定向方法有着较高的精度和较好的稳定性。     

磁保持射频继电器在移动通信设备自动测试系统中的应用研究

介绍了磁保持继电器的原理和移动通信设备自动测试系统的体系结构,重点阐述了磁保持射频继电器在直放站自动测试系统中的应用方法,并提出了使用磁保持射频继电器提高自动测试系统的安全性,防止意外损坏射频程控仪器的新方案和相应的软硬件设计.该方案在实际自动测试系统中已得到成功应用。