毫米波非均匀平面阵列无损检测三维成像算法

毫米波因其分辨力强、穿透性强、光子能量低的独特优势,在无损检测领域具有极大的潜力.针对毫米波无损检测应用,结合距离徙动算法和非均匀快速傅里叶变换的思想,提出一种适用于非均匀平面阵列的三维成像算法.该算法利用非均匀快速傅里叶变换在波数域重构信号频谱,克服了非均匀空间采样对传统基于傅里叶变换的成像算法的限制;该算法应用非均...     

考虑可信度时导弹最大射程的Bayes评估

首先讨论了一种验前数据和现场试验数据相容性检验的新方法, 考虑验前信息可信度, 研究了导弹最大射程的 Ｂａｙｅｓ 评定和 Ｂａｙｅｓ 估计。最后给出了数据分析的例子。     

微波雷达目标信号模拟器及其应用

本文为在野战条件下检测雷达测距系统的性能提供一种新型微波目标信号模拟器,闸述其工作原理及功能。除在检测雷达测距系统性能上已得到实际应用外,还论述了可以进一步开发的应用项目,因为不受场地和气候条件的限制,从而获得较好的效能、效率和效益。     

921A钢动态屈服应力的实验研究

本文采用较为先进的实验技术——高应变率下材料的分段式Hopkinson拉杆实验(分段式—维杆拉伸实验)研究了“921A”钢在高应变速率情况下的动态屈服性能,获得了很有理论和实用价值的应变率ε—功屈服应力σ_d变化曲线。同时本文简要介绍了分段式Hopkinson拉杆实验技术的基本原理和实验方法。     

超高斯随机振动环境的疲劳强化机理

针对可靠性强化试验的全轴随机振动环境的超高斯幅值分布特性开展其疲劳强化机理研究。首先通过理论分析表明RS机振动激励下试件应力仍保持超高斯分布,然后证明了同等量级下的超高斯分布比高斯分布随机应力具有更高的疲劳强化效能,从而揭示RS机全轴随机振动环境超高斯幅值分布特性的疲劳强化机理。     

Stage life testing

In progressive censoring, items are removed at certain times during the life test. Commonly, it is assumed that the removed items are used for further testing. In order to take into account information about these additional testing in inferential procedures, we propose a two‐step model of stage life testing with one fixed stage‐change time which incorporates information about both the removed items (further tested under different conditions) and those remaining in the current life test. We show that some marginal distributions in our model correspond either to progressive censoring with a fixed censoring time or to a simple‐step stress model. Furthermore, assuming a cumulative exposure model, we establish exact inferential results for the distribution parameters when the lifetimes are exponentially distributed. An extension to Weibull distributed lifetimes is also discussed.     

Avoiding self-inflicted wounds to the credibility of the US nuclear deterrent

Nuclear deterrence requires not only the reliability of a state’s strategic weapons and the willingness of its leaders to employ them but also an adversary’s appreciation of these conditions. Weapons perceived as failing to hold their targets at risk may lack deterrent value, just as retaliatory threats that are not believable may fail to deter, even if a state’s operational capabilities are robust. Both the technical and political credibility of the US nuclear deterrent may have suffered self-inflicted harm since the end of the Cold War, often as casualties of intemperate policy debates. In particular, doubts have been sowed about the reliability of aging US warheads under a science-based stockpile-stewardship regime meant to substitute for nuclear-explosive testing. Likewise, the credibility of US deterrent threats may have waned as American leaders have spoken ever more stridently about the horrors of nuclear war and nuclear terrorism, underscoring their extreme aversion to the risk of nuclear attack. Diminished credibility in both spheres threatens to compromise US national-security objectives ranging from nuclear nonproliferation to the outcomes of nuclear crises.     

防火涂料性能要求及测试方法探讨

介绍了饰面型防火涂料、电缆防火涂料、钢结构防火涂料以及混凝土防火涂料的理化性能要求及防火性能要求。重点阐述了这些防火涂料防火性能的测试方法。     

协议测试中测试序列生成方法综述

文章在介绍协议一致性测试基本概念的基础上,重点列举了测试序列的几种生成方法。对目前广泛采用的形式化描述模型,重点介绍其中基于有限状态机模型的测试序列生成方法,同时对基于扩展有限状态机以及确定有限状态机的测试序列生成方法也进行了介绍。文章对每一种方法介绍了其原理并分析了其使用中的局限。文章最后指出了在协议测试中面临的问题和进一步研究的方向。     

大口径火炮制退机内腔压力测试技术

从火炮反后座装置的特殊结构及测试技术两方面详细分析、总结了我国几种大口径火炮在内腔压力测试时出现不正常现象的原因,并从传感器的机械度、传感器的封装技术、传感器的绝热处理、传感器的频响和排气工装等几个方面改进内腔压力测试的技术工艺方法,并用改进后的方法对155-2型火炮的内腔压力进行了试验,结果表明其工艺方法可准确地测试出内腔压力曲线,从而解决了多年来火炮后座阻力测试技术中存在的关键问题。