某光电跟踪仪锁定机构检测调试仪的研制

首先介绍了光电跟踪仪锁定机构检测调试仪研制的必要性和紧迫性,接下来介绍了方位锁定机构的特点及主要功能是完成对设备方位锁定机构状态的检测,能够在单板上实现对方位锁定机构加锁、解锁的控制,并能够判断锁定机构状态,实现脱离整机单独调试、排故,并以此制定出检测调试仪的设计方案.对硬件和软件设计部分作出详尽介绍,最后对光电跟踪仪...     

一种在真空室内OLED掩模板与镀膜基片的自动分离机构

本机构主要包括磁性掩膜板夹持机构、顶柱嵌套机构、夹持器顶轮机构和掩膜板接受台。主要功能是在真空室内将完成镀膜后的掩膜板从夹持机构中分离,从而达到掩膜板与镀膜基片在真空状态下完成全自动分离动作的工艺要求,提高掩膜板在真空镀膜生产线中的分离、清洗维护及使用效率,从而提高镀膜生产线的生产效率。     

CO2激光诱导液相沉积银的机理研究

激光诱导液相沉积的机理可大致分为光电化学机理、热电化学机理和热分解机理等。通过试验及分析表明 ,CO2 激光诱导液相沉积银属于简单的热分解机理。CO2 激光起到局域热源的作用 ,在激光辐照过程中 ,光照区介质溶液及基体表面均发生了极其复杂的物理化学变化 ,最后诱导产生的银沉积在基体表面并部分扩散到了基体内部 ,成为后续化学镀铜的催化中心及过渡层     

Temperature-dependence of steady-state characteristics of SCR-type ESD protection circuits

Experimental analysis of the temperature-dependent I–V characteristics of various SCR (Silicon-Controlled Rectifier) electrostatic discharges (ESD) protection circuits have been carried out. These circuits include diode-chain-triggering SCR (DCTSCR), low-voltage zener diode trigger SCR (ZDSCR), low-voltage trigger SCR (LVTSCR) and gate-coupled low-voltage trigger SCR (GCSCR) circuits. The ZDSCR uses the zener breakdown mechanism of a reverse-biased p⁺–n⁺ diode as a trigger mechanism, the DCTSCR uses the current flowing through forward-biased diode chain as a trigger mechanism, the LVTSCR uses the grounded-gate MOSFET breakdown current as the trigger mechanism and the steady-state I–V characteristics of GCSCR also uses the avalanche breakdown as a triggering mechanism. The trigger voltage can decrease or increase with increasing temperature depending upon the triggering mechanism used in the circuit, however the holding voltages of these SCRs decrease with increasing temperature.     

新型全柔性动镜机构的设计与分析

在傅里叶变换光谱仪研制中,基于迈克尔逊干涉仪的动镜机构研制是技术难点之一,而柔性铰链机构则是动镜机构的核心部分。利用简单的平行两杆机构为基体进行复杂化设计,得出一种新型柔性铰链机构并对其进行原理分析,利用有限元分析软件Patran和Nastran对其进行模拟计算,并和传统的平行两杆机构理论计算结果进行分析比较。结果表明,新型柔性铰链机构不仅使动镜的垂直耦合位移量缩小到原来的1.4%,而且将动镜的运动自由度有效地降至一维,为后续研究者提供参考。     

机会网络中的数据转发机制分析

机会网络作为一种新兴移动无线自组织网络,在军事及民用领域展现出广泛的应用前景,数据转发机制是其核心问题。论文针对机会网络中的数据转发机制展开讨论,首先对机会网络数据转发机制与传统路由机制进行综合比较,在此基础上介绍数据转发机制面临的问题和性能评估标准,并根据数据转发机制主要特点对其进行了分类,最后对机会网络中的典型数据转发机制进行归纳。     

直线电机驱动的经纬仪调焦机构设计

传统的凸轮调焦机构和丝杆丝母调焦机构存在结构复杂;加工、装调难度大;在传动链中引入齿轮传动,不可避免的会产生空回现象,进而导致整个机构存在传动效率低、响应速度慢、重复定位精度差等问题。为了弥补传统调焦机构的不足,设计了一种直线电机驱动的调焦机构,给出了新调焦机构的设计计算过程。直线电机驱动的调焦机构已成功应用于光电经纬仪中。实验证明,该机构的重复定位精度〈0.004mm,优于传统的调焦机构。     

基于参数化设计的连杆机构

以二齿四杆机构为例介绍具有相同或相似特征的连杆机构运动分析。利用Visual Basic程序来实现参数化机构的角位移、角速度、角加速度等相关运动分析，使计算机与机械有机结合，实现精确、快速设计要求。     

并联机构的发展及应用

绍了国内外并联机构的发展,通过与串联机构的比较,详细说明了并联机构的特点及其在各个领域中的应用.六杆并联机构是并联机构的一种特殊形式,文中具体阐述了其工作原理,并结合上海第三代同步辐射装置软X谱学显微光束线中使用的特殊六杆并联调节机构,对其特点做进一步说明.     

航空光电遥感器高精密紧凑型调焦机构的设计

针对航空光电遥感器在不同工作环境下会产生离焦这一问题,采用移动镜组方式进行调焦,以保证其成像质量。该调焦机构采用消间隙丝杠螺母副作为传动机构,采用六个精密轴承及弹性预紧组件作为导向机构,同时采用一对电涡流传感器及一个菱形被检测件作为测位移传感器,在有限包络尺寸下最大程度保证其调焦精度。从传动误差和传感器组件误差两方面对调焦机构进行精度分析,并且搭建实验平台对其进行了传动定位精度实验和晃动精度实验。实验结果表明,该调焦机构的传动定位精度在±6 μm以内,晃动精度在±4″以内,满足光学系统提出的调焦精度设计要求。     

抗干涉齿轮集机构优化编码的分层判据

抗干涉齿轮集（CMG）机构是一种可用于确保要害系统安全性的微型或微小型机械组合锁的密码鉴别机构。CMG机构复合齿轮的齿牙编码是 CMG机构设计的核心问题。为了获得齿轮层数最少的最优编码结果,建立了基于变换思想的 CMG机构编码新理论,该理论由二维迷宫映射、编码类型细分、编码分层判据等构成。作为前提,以迷宫映射图为工具,论述了 CMG机构的密码鉴别原理,定义了 CMG机构的编码问题。采用反证法证明了 CMG机构编码的分层判据（关键陷阱格点异层的“十字叉”判据）的原理,并以一个算例说明了应用“十字叉”判据实现关键陷阱格点分层的具体方法。     

VSS based session setup mechanism in IMS

This paper proposes a novel session setup mechanism in IMS (IP Multimedia Subsystem) by introducing the functional entity termed VSS (Visitor Subscriber Server) which is used to provide registration and location management. The new mechanism aims at improving session setup procedure by a betterment of location management in IMS. Through the use of two-tier subscriber information database constituted by the HSS (Home Subscriber Server) and the VSS, the new mechanism seperates the registration procedure and location management from the S-CSCF (Serving-Call’Session Control Function), and makes them be handled by the VSS. At the same time, the new mechanism updates the signaling procedure of registration and session setup. With VSS based location management, the cost of registeration and session setup procedure as well as the delay of session setup procedure become lower. The cost and delay functions of the new session setup mechanism as well as the cost function of new registeration are deduced. Then, simulations and analysis verify that the performance of this new mechanism gets the benefit in cost and time.     

Effect of load distribution in path protection of MPLS

We analyse and compare a protection mechanism based on load distribution with a typical protection mechanism in an multiprotocol label switching (MPLS) network. The protection mechanism based on load distribution is modelled as a fully shared mechanism (FSM) and the typical protection mechanism is a partially shared mechanism (PSM). By comparing the FSM and the PSM, we numerically analyse the effect of load distribution in path protection of MPLS. The comparison is based on numerical equations representing the relationship between service reliability and resource utilization. From the equations, we show that both the FSM and the PSM have a tradeoff between service reliability and resource utilization. In addition, we provide solutions for the FSM and the PSM to determine the amount of bandwidth occupied according to the requested service reliability. The comparison of the FSM and the PSM shows that the PSM cannot provide greater service reliability than the FSM under the same utilization. In addition, the PSM is not capable of accommodating greater resource utilization than the FSM for the same level of service reliability. However, an appropriate choice of the number of protection paths allows the PSM to provide the same level of service reliability as the FSM. The choice is the maximum among the possible numbers of protection paths of the PSM. In short, the typical protection mechanism is as good as the FSM in terms of service reliability and resource utilization even though the FSM is an attractive alternative to the typical protection mechanism. Copyright © 2003 John Wiley & Sons, Ltd.     

网络化治理理念下我国社会矛盾纠纷化解机制探索

文章针对新时期社会矛盾特点和传统管理模式失效现象,说明了网络化治理模式应运而生,该模式从强化网络合作机制、完善网络协调机制、落实网络责任机制等方面探索社会矛盾机制的化解。     

超声电机驱动的轻量化扫描机构高精度控制

为实现卫星高分载荷扫描驱动机构的轻量化,以超声电机为驱动部件,设计了一款扫描驱动机构,质量仅为传统的步进电机加谐波减速器驱动方案的15%。构建了扫描驱动机构驱动控制器,配合21位绝对式光电编码器作为位置反馈传感器,对扫描驱动机构高精度控制方法进行了研究。针对超声电机在精密控制中的非线性及时变性,在对比总结比例、积分、微分(PID)控制、模糊控制、神经网络PID控制算法的基础上,设计了一种基于专家规则的PID控制器,并结合超声电机实时温度作为前馈控制在线调节控制器控制参数,最后进行了指向控制和速度稳定度实验研究。实验结果表明：令扫描驱动机构指向20°时,稳态指向精度优于2″,在3.3 r/min情况下扫描驱动机构速度稳定度优于±1%,能够满足卫星载荷对扫描驱动机构高精高稳的控制需求。     

改进的红外光楔测量装置及应用分析

锗光楔角度的测量无法采用一般光楔的检测方法，本文对原有的楔形角测量装置进行了改进。与原装置相比，采用了多个微动机构，底座采用了720多齿分度台；绕光轴的转动采用螺旋－杠杆微动机构，以替代原先的摆动杠杆机构，可以更有效地利用搜索逼近法完成对楔角的测量。本装置除用于红外光楔的锗晶体测量之外，亦可用作其他光学玻璃的角度测量和分度使用。     

利用双证书机制改进SSL/TLS协议

在PKI技术规范发展的过程中目前形成两种证书机制:单证书机制和双证书机制[1]。近年来,在欧洲等国家又掀起多证书协议的研究[2],但尚不成熟。单证书是目前广泛存在和应用的证书机制,但用证书的加密和签名在PKI中是两种应用,因为,在SSL协议的应用中都采用双证书机制。为此,论文重点讨论了双证书机制的实现与应用,以及它对SSL/TLS通信协议进行的安全性改进,如改进了TLS的访问控制、增加抵抗DoS攻击特性等相关研究。     

基于超声电机的轻型指向机构及其指向误差分析

在探月工程中, 为了实现基于空间应用光谱仪的多目标光谱探测, 需要设计满足轻小型和高可靠性的二维指向机构。目前, 超声电机作为驱动源, 精密电位计作为一种位置传感器, 因其自身的优良性能正逐步应用于精密仪器和定位技术中。基于此, 设计了由超声电机、精密电位计和扫描镜组成的二维指向机构, 并以一维指向模型为工程样机, 通过设计闭环控制电路和指向控制机制进行功能测试, 验证了该机构空间应用的可行性。为了测量精度, 搭建实验室测试平台, 并进行多次指向试验, 通过对测试结果进行分析, 提出提高指向精度的方案。     

Smart pay access control via incentive alignment

We use game theoretic models to show the lack of incentives in the transport control protocol congestion avoidance algorithm and the consequential system-wide network problems. We then propose a Vickery-Clark-Groves (VCG) mechanism-based access control mechanism for packet traffic. Our mechanism is called "smart pay access control (SPAC)". We prove both the incentive compatibility and individual rationality of SPAC, which achieves Pareto efficient allocation of network resource. The computing problems are NP-hard for the general VCG mechanism, whereas our mechanism computes the winner's determination problem as fast as a sorting algorithm. The speed of SPAC makes it feasible for the real world usage. As a positive side effect, the mechanism provides the base for a pricing scheme, which we present in the context of the differentiated service architecture for the Internet.