多普勒效应在安全行车中的应用

将多普勒效应运用于汽车行驶及交通管理上,使汽车具有自动刹车功能,管理上有超速报警功能,从而降低交通事故的发生率。     

Hard missile impact on reinforced concrete

New penetration, scabbing and perforation formulae are derived for use in the design of reinforced concrete barriers to withstand impact by hard missiles. This is done by using dimensional analysis together with physical theories for the various impact processes. This leads to impact formulae with unknown coefficients which are then determined by an analysis of all available test data. The new formulae so derived are simple and, because of their parametric formulation, have a range of applicability easily definable in terms of impact parameters. The analysis indicates that some recently proposed impact formulae are not safe from the point of view of barrier design because the test data used for their derivation was affected by global movement of the barriers which reduced the measured local damage.     

日本神奈川县通信网络结构的演变

本文介绍了在日本神奈川县的电话网络结构的演变，详细分析了网络调整的必要性和具体实施方案通过调网前后网络性能的比较，说明了网络调整的重要性，文章学结合北京通信网现状，提出了北京网络结构发展构想。     

微型晶体振荡器的研制

本文介绍的微型晶体振荡器有普通型、快速加热简易恒温型、多信号输出等三种类型晶振.其中快速加热简易恒温型在常温下工作时,频率—温度特性达10~(-7),在正温范围工作时,频—温特性达lO~(-6)/(0℃～80℃),多信号输出型目前已作出的每台晶振有1OMHz、5MHz、1MHz、500KHz、1OOKHz等五个频率的信号输出,其频率稳定度为10~(-5).晶振的振荡电路、放大电路、温控电路及分频电路,均以集成技术来实现,并与石英晶体谐振器—同用电阻焊密封于16×16×5.5(mm)~3的金属盒内,其重小于5克.