Robust tracking servo system considering force disturbance for the optical disk recording system

This paper proposes a new robust tracking servo system for the optical disk recording system with feedforward controller based on the prediction of the tracking error. In optical recording systems, the feedback servo system must suppress the influence of force disturbance and parameter variation. To overcome this problem, this paper designs the robust feedback control system by using coprime factorization and disturbance observer. The detecting signal of the optical disk recording system is only a tracking error. Hence, the feedforward controller of the proposed tracking control system is constructed based on both the "zero-phase-error tracking" control theory and the prediction of the tracking error. The experimental results point out that the proposed tracking servo system has a quick and precise tracking response and keeps the residual tracking error below its tolerance.     

A control method for a nonlinear multivariable system: applicationto interstitial laser hyperthermia

An original adaptive control method is presented for controlling a nonlinear multivariable system. The method, which could be described as a modified quasi-linear approach, involves dividing the source excitation into a series of pulsing rounds and is implemented as a control algorithm on a computer. The theory underlying the method is developed with reference to an application involving temperature control in interstitial laser hyperthermia. In this application, the method is both successful and necessary to achieve optimally uniform elevated temperatures in a ground beef phantom. Apart from variable and parameter definitions, the method is otherwise general and might be useful for controlling a nonlinear system in which no prior exact characterization of the system is possible. Simulations were conducted to assess the effectiveness of the method in systems for which the unit excitation response changes by factors ranging from zero to three over the total period of excitation. In each case the method has proven stable.     

可二次开发的通用视频捕获记录系统

在实际研发的基础上，提出并实现了一种既支持应用软件又支持硬件控制程序的二次开发的通用视频捕获记录系统，详细地阐述了该系统的设计思想及工作流程。     

轻小型立体相机光学系统研制

针对民用低成本立体成像的应用需求,设计了一种轻小型立体成像相机光学系统,旨在于在250 km轨道高度地面实现像元分辨率为50 m的立体成像,该光学系统在焦面探测器配合下,既可实现立体成像,又可实现大画幅面阵成像。该系统焦距f'=32 mm,视场角2=66,相对孔径D/f'=1:6.8,工作谱段450~750 nm。光学系统设计中,采用反远距系统与消色差显微物镜两种光学结构组合的形式,最终全视场光学传递设计值优于0.49@78 lp/mm,几何畸变小于0.1%,边缘视场与中心视场照度比0.83,边缘视场与主光线入射角小于15。光学系统采用精密定心装配,并对成像质量进行了检测,装调后相机光学系统传递函数的测试值均优于0.4@80 lp/mm,满足实验室静态传递函数优于0.2的指标。该光学系统在成像幅宽、几何畸变数值等方面的指标均优于国内外典型立体相机。     

Fast optical recording media based on semiconductor nanostructures for image recording and processing

Fast optical recording media based on semiconductor nanostructures (CdTe, GaAs) for image recording and processing with a speed to 10⁶ cycle/s (which exceeds the speed of known recording media based on metal-insulator-semiconductor-(liquid crystal) (MIS-LC) structures by two to three orders of magnitude), a photosensitivity of 10^?2V/cm², and a spatial resolution of 5–10 (line pairs)/mm are developed. Operating principles of nanostructures as fast optical recording media and methods for reading images recorded in such media are described. Fast optical processors for recording images in incoherent light based on CdTe crystal nanostructures are implemented. The possibility of their application to fabricate image correlators is shown.     

扩散光层析成像系统研究现状及发展

对国内外有关扩散光成像系统进行总结分析,将成像系统分为三大部分,对每部分进行分类并分析了各自的优缺点。分析介绍了国内外具有代表性的扩散光层析成像系统,总结了成像系统存在的问题。     

Modeling and compensation of asymmetry in optical recording

Asymmetry, also known as domain bloom, is a systematic imperfection caused by the writing process in optical or magneto-optical recording. At the reading end of the system, asymmetry causes shifts of adjacent signal transitions in opposite directions. We present a simple nonlinear model for the replay signal in the presence of asymmetry. The model is specified by a single parameter, which is proportional to asymmetry, and its accuracy is demonstrated by application to replay signals from digital video disk drives. Based on the proposed model, a maximum-likelihood sequence detector is designed for replay signals with asymmetry. Simple modifications of the proposed detector lead to significant reductions in complexity, while the attainable performance, evaluated both analytically and through error-rate simulations, is superior to that of conventional techniques.     

Diode lasers for mass market applications: optical recording andprinting

The existence of inexpensive semiconductor diode lasers has led to realization of consumer products in the home entertainment and personal computer industries that are already successful and promise to continue to grow in value. For example, optical recording has proven to be a technology that not only has become a dominant factor in the audio market (CD player), but has found markets as memory peripherals for personal computers and the playback of prerecorded video. In addition, diode laser printers for personal computers will become a large market. Diode-laser-based optical recording and printing systems are reviewed in this paper, as are the properties of the diode lasers that allow these systems to operate so well. Future developments in diode laser technology that will allow enhanced or new systems are also described     

我国光纤通信系统演进的阶段与展望

光纤通信商用化以后,由于市场需求和技术进步的推动,光纤通信系统依次经历了PDH光传输时代、SDH光传送网时代、大容量WDM传输时代等发展时代。考察了我国光纤通信系统技术的演进与发展,并且指出今后的光纤通信系统将向超高速大容量,分组化,智能化,全光网方向发展。     

1:1方式带备纤监控的光路检测系统研制

1:1方式带备纤监控的光路检测系统采用ARM核的32位低功耗微处理器作为系统控制核心,系统采用嵌入式μCOS-II2操作系统,可实现主备光纤信道状态同时检测,发现故障时瞬时切换到备用信道,切换时间小于15ms,大大低于ITU-TG.841标准所规定的50ms,确保光路通信畅通无阻,具有实时性强、动态性能良好,运行稳定可...     

空间光学遥感系统设计及反射膜的研制

本文采用Code V软件设计一种空间光学遥感系统,该系统的F数为2,入瞳直径为125mm,出瞳直径为39mm,畸变小于05,点列图均方根直径小于5μm。根据光学薄膜基础理论,设计出铝基碳化硅的表面镀镍后,波长1064±5nm处R>985%的反射膜。选择铝基碳化硅作为反射镜的基底材料,采用改性的镍层再镀反射膜的方法,在OZZSQ900型箱式真空镀膜机上完成了铝基碳化硅基底镀镍层铝膜的制备。采用岛津UV 2600i光谱仪对镀膜样品的反射光谱进行测试,测试结果满足设计要求。该研究具有重要的实际意义和工程价值。     

多参量一体化光纤传感器及标校系统的研制与开发

提出一种集温度、压力和流量多参数同时测量的新型光纤传感器,并对其原理和结构、工艺设计展开研究工作。采用靶式与悬臂梁结构相结合的机敏结构、薄壁压力应变筒结构等集成在同一传感器探头上,并利用四只光纤光栅使得温度、压力和流量三个参数得以同时检测。利用光纤光栅两两之间波长移动量相差或相和,使温度与流量、压力交叉敏感问题得以解决。同时开发了光纤传感器标校系统,这一系统可以较准确实现对所研发的多参量一体化传感器的测试结果进行检测和标校。     

Advanced optical disk mastering and its application for extremelyhigh-density magnetic recording

As the demand for recording density becomes stronger, mastering technology becomes more important along with its level of mechanical precision. To visualize such an important technology, the author presents one of the latest examples of optical disk mastering technologies in the application of preembossed magnetic disks. The preembossed magnetic disks have emerged from the integration of two existing technologies: one is magnetic recording technology and the other is optical disk technology. The effect of precision machining for such development is described in detail, along with suggested possible directions of further development in precision mechatronics     

视频服务器及其在收录系统中的应用

根据河南电视台新闻中心新闻网的具体情况,介绍了视频服务器的工作原理和功能。通过对收录系统业务流程及其系统结构的描述,着重分析和研究了其核心设备视频服务器在收录系统中的计划编排、控制、手动、自动收录、分段切片收录、收录实时监测等应用特点,及其在安全方面的设计。     

光纤技术的发展及其在光通信中的应用

随着光纤网络的快速增长，光纤技术的发展越来越重要。光子晶体光纤是一种新型光纤，它将会极大地影响光通信的发展，为此对传统光纤进行了分析，对光子晶体光纤的性质和应用前景也进行了讨论和评价。     

光控光开关的发展和应用

综述了光控光开关的发展状况以及它在未来全光网络中的应用 ;分析了几种典型的光控光开关实现方案的结构及原理 ;详细论述了光控光开关在全光网络中的各种应用 ,并通过分析和论述指出光控光开关将在未来的大容量全光网络中发挥关键作用。     

基于光学标测技术和MEA技术的植物电研究概述

植物电信号的研究进展很大程度上依赖于测量技术的发展。目前对于微电极等测量技术而言,多方面因素的限制使得同时测量2个以上细胞的电活动基本无法实现,因此对植物群体细胞电活动规律的研究进展较小。本文介绍了2种可以同时对植物群体细胞电活动进行测量并具有空间分辨率的测量技术-依赖于电压敏感染料的光学标测技术和微电极阵列技术。分别介绍了光学标测技术的测量原理、电压敏感染料的特性、系统构成、信号提取方法等内容,并列举了在植物细胞电信号测量方面的应用实例,概述了影响植物电信号光学标测的因素;阐述了微电极阵列技术的系统组成、阵列微电极的特征、测量依据及模型、影响测量的因素,并对阵列微电极在玉米幼根测量中的应用做了简要介绍。最后对这2种测量技术在植物电信号测量中存在的一些问题进行了讨论。     

HermesB: a continuous neural recording system for freely behaving primates

Chronically implanted electrode arrays have enabled a broad range of advances in basic electrophysiology and neural prosthetics. Those successes motivate new experiments, particularly, the development of prototype implantable prosthetic processors for continuous use in freely behaving subjects, both monkeys and humans. However, traditional experimental techniques require the subject to be restrained, limiting both the types and duration of experiments. In this paper, we present a dual-channel, battery-powered neural recording system with an integrated three-axis accelerometer for use with chronically implanted electrode arrays in freely behaving primates. The recording system called HermesB, is self-contained, autonomous, programmable, and capable of recording broadband neural (sampled at 30 kS/s) and acceleration data to a removable compact flash card for up to 48 h. We have collected long-duration data sets with HermesB from an adult macaque monkey which provide insight into time scales and free behaviors inaccessible under traditional experiments. Variations in action potential shape and root-mean square (RMS) noise are observed across a range of time scales. The peak-to-peak voltage of action potentials varied by up to 30% over a 24-h period including step changes in waveform amplitude (up to 25%) coincident with high acceleration movements of the head. These initial results suggest that spike-sorting algorithms can no longer assume stable neural signals and will need to transition to adaptive signal processing methodologies to maximize performance. During physically active periods (defined by head-mounted accelerometer), significantly reduced 5-25-Hz local field potential (LFP) power and increased firing rate variability were observed. Using a threshold fit to LFP power, 93% of 403 5-min recording blocks were correctly classified as active or inactive, potentially providing an efficient tool for identifying different behavioral contexts in prosthetic applications. These results demonstrate the utility of the HermesB system and motivate using this type of system to advance neural prosthetics and electrophysiological experiments.     

基于光纤传感的智能安防报警系统设计与开发

针对现有安防传感系统高能耗、易受电磁干扰、成本高和铺设困难等缺陷,提出了一种低能耗、高灵敏度、不受电磁干扰的智能光纤传感安防报警系统。系统传感器采用微弯型阶跃光纤结构,在分析微弯光纤传感器光能损耗与谐振频率相对折射率差函数关系的基础上,优化了传感单元的结构参数。实验首先对干扰抑制算法进行测试,从波形分布看出,采用本算法后噪声得到了大幅抑制。在此基础上,又采用系统对不同伪目标干扰进行了测试。选用功率为2.5 mW的650.0 nm激光器、光纤功率计、微弯光纤架和纤芯9 μm的微弯光纤传感器搭建了光纤微弯传感实验,对4种不同安防状态的光电响应特征进行了分析。结果表明,针对不同干扰类型只要采用相应的信号分析手段就能有效降低系统误识别的概率。由此可见,光纤微弯传感系统具有高灵敏、低能耗、抗干扰等优势,满足设计要求,在智能安防领域具有很好的应用前景。     

Rayleigh-Sommerfeld and Helmholtz-Kirchhoff integrals: applicationto the scalar and vectorial theory of wave propagation and diffraction

Approximations for known integral solutions of the scalar Helmholtz equation (the Rayleigh-Sommerfeld (RS) integrals of type I and II) are discussed. The validity range of the approximated RS I integral for large, but finite distances from the boundary plane is calculated as a new result. The scalar Kirchhoff boundary conditions leading to a rough approximation of an aperture diffraction problem are inspected, and a new spatial frequency solution in the aperture plane is given. Published measurements and known approximate vectorial boundary values formulated with the Hertz vector are compared with the outcome of the traditional Kirchhoff theory. For the field propagating from light waveguide endfaces into a homogeneous medium, the polarization effects in the far-field are considered by approximating the near-field for weakly guiding fibers with a Hertz vector ansatz. Comparison with measurements shows that the polarization induced asymmetry of the far-field is small in comparison with the experimental uncertainties. Finally, the proper applications for the RS I; II integrals are clarified as opposed to using the scalar or vectorial Helmholtz-Kirchhoff integral