基于Windows CE.NET的IP视频会议系统设计

由于传统视频会议系统的实时性不能很好满足多媒体流视频会议系统,设计了一套基于嵌入式操作系统WindowsCE.NET的视频会议系统.系统主要由音视频编解码、会议管理、网络传输、网络质量控制4部分组成,采用H.264编码技术对视频进行编解码;采用G.723标准对音频进行编解码;采用UDP/RTP/RTCP协议传输多媒体流信息和TCP协议传输数据信息及其控制信息;同时采用基于H.332协议的IP组播技术来实现点对多点的通信.这种分布式、松散耦合的系统结构较好地解决了多媒体会议系统的规模扩展问题.     

整体型钢定位架预埋超长基础地脚螺栓的施工技术

针对工程实际需要,设计使用了型钢定位架来预埋超长基础地脚螺栓,并通过实践总结,形成了整体型钢定位架预埋超长基础地脚螺栓的施工技术。实践证明,该项技术具有预埋位置精确、施工周期短、需用设备少、操作工艺简单、附加费用较少等优点。     

Assessment of strain gradients affecting the performance of 3-D strain rosettes – relevant to the analysis of cement mantle strains in total hip replacements

A large scale model analysis, using embedded strain gauges, of the strain distribution in the cement mantle surrounding a femoral prosthesis is underway. In order to predict, and so avoid, positions of locally high strain gradients in this model, a finite element and experimental analysis of a similar problem was undertaken. For this purpose, a loose fitting rectangular steel insert inside a surrounding rectangular epoxy sheath was used to model an extreme case of the torsional and bending components of hip joint load. The axial component of joint load was modelled using an axisymmetric finite element model of a tapered shaft. The finite element results were used to determine suitable positions for embedding gauges in the experimental model. Results showed that the finite element analysis failed to adequately model the close sliding fit between the steel insert and epoxy. Altering the experimental model to artificially replicate the finite element contact conditions produced good correlation in bending, with experimental strains agreeing with simple bending theory to within 6%. Satisfactory correlation under torsional loading was not obtained, but strain magnitudes were low. Predicted positions for embedding gauges give conservative results, lessening the possibility of strain gradient induced error in the large scale model test of the cement mantle and prosthesis.     

大型机械高精度安装校准基准给定的新方法

介绍一种大型机械安装校准的新方法，论述了利用拉直的钢丝和新型电容测微仪及多功能核准检具对大型机械安装校正给定高精度基准的方法。同时还简要介绍了电容测微仪在校准中的应用及其标定方法，以及多功能检具的功能特点和设计原则等。     

An estimate of the achievable accuracy of the connections and fittings of precision articles

The possibility of using end gauges, special quartz plates and measuring jaws to model various fittings and connections of articles is investigated. The mutual position and deformations of the joined surfaces and also the effect of different factors on the property of the fittings in connections are considered. The results of the modeling enable one to estimate the optimum achievable accuracy of the fittings and connections of articles.Translated from Izmeritelnaya Tekhnika, No. 9, pp. 29–32, September, 2004.     

简易船载航海数据记录仪S-VDR的设计与实现

从性能标准要求、系统原理与功能、系统结构组成等几个方面对简易船载航海数据记录仪（S—VDR）进行了简单的介绍。并介绍了运用模块化的设计思想实现的S-VDR系统。该系统综合应用了嵌入式工控机、单片机、多媒体技术、数据压缩技术及通信技术．可以根据不同船舶的要求进行配置，对于远洋船舶和沿海船舶均有使用价值。     

Stiffness and Reinforcement Effect of Electrical Resistance Strain Gauges

Abstract:  The increasing use of low-modulus materials, on which the reinforcement effect of the electrical resistance strain gauge is not negligible, has re-opened the research interest into this issue. This study deals with the evaluation of stiffness, and of the strain gauge Young's modulus involved in the estimation of both the global and the local reinforcement effect; the relationship between the strain gauge stiffness and the local reinforcement effect is also analysed. In particular, the experimental technique used to determine the stiffness of some commercial strain gauges is described. The results show that the strain gauge stiffness alone does not permit an accurate evaluation of the local reinforcement effect.     

VxWorks系统的BSP设计与实现

BSP(Board Support Packet)是介于硬件和实时操作系统VxWorks之间的底层软件开发包,为VxWorks系统提供了标准的硬件接口函数,保证了VxWorks系统能够运行在不同的硬件平台上.介绍了BSP的概念,并以嵌入式微处理器MPC8280构成的硬件平台为例详细介绍了BSP的开发过程.     

The calibration of CERL-Planer capacitance strain gauges

CEGB-Planer capacitance strain gauges are used extensively for monitoring the deformation of components operating in the creep range. However, there are significant differences between the way the gauges are installed for use and the way they are installed for calibration. This paper describes the various types of calibrations that have been carried out to identify the errors associated with these differences and the results show that, providing the manufacturers' recommendations are adhered to, the errors are acceptably small.     

加成型液体硅橡胶用铂配合物催化剂

介绍了加成型液体硅橡胶用铂配合物催化剂,包括铂-乙烯基硅氧烷配合物的制备及改进方法、包埋型铂-乙烯基硅氧烷配合物的制备方法（喷雾干燥法、水分散液法、热熔法）、铂-乙炔基（铂-炔醇、环二烯烃铂-炔醇、三有机磷铂-炔醇）配合物的制备方法,以及醇改性氯铂酸（辛醇改性氯铂酸、乙醇改性氯铂酸）的配制.