风对旋转弹丸弹道轨迹的交叉影响

本文解释了风对旋转弹丸弹道轨迹交叉影响的物理本质,分析了风对直射弹道和曲射弹道的影响。指出横风对于直射弹道的交叉影响引起的射程偏差较大;而纵风对于曲射弹道的交叉影响所引起的方向偏差在大射角时也较为明显。     

榴弹射表编拟中符合系数和符合对象的综合选取

基于综合符合思想,通过诸参数对于弹道影响敏感特性的分析,及诸符合方案的对比论证,提出了在一个射角下,以零阻力系数C_(xo)和相对静力臂系数h/l作为符合系数,以射程X和偏流Z为符合对象的符合方案;同时,与国外符合方案进行了对比。     

工程制图教学内容与课程体系改革的探讨

在研究了工程制图教学内容与课程体系改革的目的、任务及相关课程的基础上,给出了适合我院培养目标的比较合理的教学内容与课程体系．     

有限元网格自动生成的Delaunay算法

介绍一种有限元网格自动生成算法,算法对点的位置没有任何限制,增加新点时,可在原有网格基础上生成新的符合Delaunay性质的三角形有限元网格．     

双三次参数曲面片的逼近求交法

本文提出了一种新的曲面求交方法,这种方法基于曲面控制网格的“子”分方法,只要控制网格足够逼近曲面,则通过对控制网格处理一系列特殊的直线与三角形求交问题,就可迅速、逼近地求出两张双三次曲面片的交线。     

1949-1954:台湾在我党军事斗争中战略地位的演变

1949至1954年期间,台湾在我党军事斗争中战略地位的演变,大抵经历了三个阶段:1949年2月至同年底,台湾战略地位的凸显与1949年攻台设想的放弃;1949年底至1950年11月,对台战略重点地位的形成与军事战略重心向东北方向的转移;1950年11月至1954年7月,对台战略防御体系的建立与“解放台湾”任务的重新提出。本文考察了这一演变过程。     

Skewness correction X̄ and R charts for skewed distributions

This paper proposes a skewness correction (SC) method for constructing the and R control charts for skewed process distributions. Their asymmetric control limits (about the central line) are based on the degree of skewness estimated from the subgroups, and no parameter assumptions are made on the form of process distribution. These charts are simply adjustments of the conventional Shewhart control charts. Moreover, the chart is almost the same as the Shewhart chart if the process distribution is known to be symmetrical. The new charts are compared with the Shewhart charts and weighted variance (WV) control charts. When the process distribution is in some neighborhood of Weibull, lognormal, Burr or binomial family, simulation shows that the SC control charts have Type I risk (i.e., probability of a false alarm) closer to 0.27% of the normal case. Even in the case where the process distribution is exponential with known mean, not only the control limits and Type I risk, but also the Type II risk of the SC charts are closer to those of the exact and R charts than those of the WV and Shewhart charts. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 555–573, 2003     

Two novel critical shock models based on Markov renewal processes

In this paper, we investigate systems subject to random shocks that are classified into critical and noncritical categories, and develop two novel critical shock models. Classical extreme shock models and run shock models are special cases of our developed models. The system fails when the total number of critical shocks reaches a predetermined threshold, or when the system stays in an environment that induces critical shocks for a preset threshold time, corresponding to failure mechanisms of the developed two critical shock models respectively. Markov renewal processes are employed to capture the magnitude and interarrival time dependency of environment-induced shocks. Explicit formulas for systems under the two critical shock models are derived, including the reliability function, the mean time to failure and so on. Furthermore, the two critical shock models are extended to the random threshold case and the integrated case where formulas of the reliability indexes of the systems are provided. Finally, a case study of a lithium-ion battery system is conducted to illustrate the proposed models and the obtained results.     

SAR图像中道路的检测

提出一种两步算法用于从合成孔径雷达 (SAR)图像中无监督地提取线性特征 ,特别是提取公路网。第一步利用局部线特征检测算子提取线基元 ,为此提出一种改进的均值比率 (RoA)算子 ,应用SAR图像的内在统计特性 ,保证较高的准确率 ;第二步引入公路结构特征的先验信息 ,对提取的线基元进行组织 ,获得比较宏观的线性结构。文中的方法通过ERS -1图像加以验证。     

基于人机工程学的防暴武器安全因素研究

文章运用现代科学——人、机、环境系统工程学分析探讨了防暴武器使用事故的原因,提出预防事故的措施。