大型水面舰艇舷侧水下防雷舱吸能结构论证设计

分析了大型水面舰艇舷侧水下防雷舱的设计 ,根据板的破坏模式进行了吸能量的计算 ,分析并比较了防雷舱的传统设计与在此基础上加吸能结构后各自的吸能量 ,从而得出了防雷舱的一种新的结构设计 .     

轨、姿控固体燃气发生器式动力系统研究

概述了固体燃气发生器的特点及发展状况,提出了如何进一步研究的建议。     

DJ去噪法在语音信号处理中的应用

对被污染的语音信号的去噪进行了讨论与分析,应用异于DJ硬、软门限的新门限法对语音信号进行了去噪的仿真计算,结果确实优于DJ软、硬门限的去噪法     

对DJ小波VisuShrink去噪法中j0取值的分析

ＤＪ小波ＶｉｓｕＳｈｒｉｎｋ去噪法在数字信号处理方面的应用已十分广泛,但是去噪后恢复信号质量的优劣与低分辨率截断参数ｊ０的选取是密切相关的,而ｊ０的选取又与被污染信号的噪声指数σ以及采样率有关。这篇文章对这些关系进行了分析,并给出了仿真计算的结果,分析与计算的结论对如何选取最佳低分辨率截断参数ｊ０具有一定的指导意义。     

扭力轴头的堆焊修复加激光强化

本文对某重载车辆扭力轴轴头的堆焊修复加激光强化工艺进行了试验研究.优选了激光强化的工艺参数;分析了堆焊及激光强化层的组织;并进行了硬度及接触疲劳试验.试验结果表明:堆焊加激光强化层的硬度高,其接触疲劳性能比原材料高频淬火略有提高;堆焊加激光强化修复扭力轴轴头具有较高的经济效益.     

采用RLS算法的功率倒置阵列的性能

为解决功率倒置阵列采用LMS算法时收敛速度和稳态失调误差不能兼顾的缺点,提出了采用RLS算法实现功率倒置阵列的方法。仿真结果表明,功率倒置阵列采用RLS算法和LMS算法都能达到较好的抗干扰效果。和LMS算法相比,RLS算法同时具有收敛速度快和稳态失调误差小的优点,代价是计算量增大。     

Designing a degradation experiment

Degradation experiments are widely used to assess the reliability of highly reliable products which are not likely to fail under the traditional life tests. In order to conduct a degradation experiment efficiently, several factors, such as the inspection frequency, the sample size, and the termination time, need to be considered carefully. These factors not only affect the experimental cost, but also affect the precision of the estimate of a product's lifetime. In this paper, we deal with the optimal design of a degradation experiment. Under the constraint that the total experimental cost does not exceed a predetermined budget, the optimal decision variables are solved by minimizing the variance of the estimated 100pth percentile of the lifetime distribution of the product. An example is provided to illustrate the proposed method. Finally, a simulation study is conducted to investigate the robustness of this proposed method. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 689–706, 1999     

空天防御体系及技术发展

网络空间攻防技术对国家安全影响的地位日趋上升,已成为世界主要国家超前布局、优先发展的重要技术领域。文章系统梳理了主要国家在态势感知技术、攻击技术、防御技术、控制技术、支援保障技术等领域所取得重要进展和面临的问题,重点分析和前瞻了网络空间攻防技术发展的新趋势和新途径。     

2(1/2)谱在直升机声信号特征提取中的应用

介绍了四阶累积量对角切片的一种定义,分析了其傅里叶变换(212谱)在提取三次相位耦合特征方面的良好性能及其估计方法;将其应用于具有三次相位耦合的直升机声信号特征提取。仿真结果表明,利用该方法能够分析信号的三次相位耦合信息,且具有计算方法简单、运算速度快及良好的抑制高斯噪声的优点。实际的数据处理结果验证了该方法的有效性。     

A general model for accelerated life testing with time‐dependent covariates

This paper introduces a general or “distribution‐free” model to analyze the lifetime of components under accelerated life testing. Unlike the accelerated failure time (AFT) models, the proposed model shares the advantage of being “distribution‐free” with the proportional hazard (PH) model and overcomes the deficiency of the PH model not allowing survival curves corresponding to different values of a covariate to cross. In this research, we extend and modify the extended hazard regression (EHR) model using the partial likelihood function to analyze failure data with time‐dependent covariates. The new model can be easily adopted to create an accelerated life testing model with different types of stress loading. For example, stress loading in accelerated life testing can be a step function, cyclic, or linear function with time. These types of stress loadings reduce the testing time and increase the number of failures of components under test. The proposed EHR model with time‐dependent covariates which incorporates multiple stress loadings requires further verification. Therefore, we conduct an accelerated life test in the laboratory by subjecting components to time‐dependent stresses, and we compare the reliability estimation based on the developed model with that obtained from experimental results. The combination of the theoretical development of the accelerated life testing model verified by laboratory experiments offers a unique perspective to reliability model building and verification. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 303–321, 1999