Excel在数值计算中的应用

本文介绍了用Excel电子表格解决数值计算中的计算问题，并用图表形式表示出运算结果。     

浅析现代战斗机翼-身接头的构造和连接形式

较详细分析了现代战斗机翼-身接头的构造和连接形式以及各种形式的优缺点和选择这些结构形式时的注意事项,并对现代战斗机翼-身接头形式未来的发展趋势作出预测。     

Influence of the gravitational vertical on geometric visual illusions

The occurrence of geometric orientation illusions and the perception of ambiguous figures were analyzed in 24 subjects during static body tilt relative to gravity on Earth. Results showed that illusions such as the Rock's diamond/square, the Ponzo illusion, and orientation contrast illusions occurred less frequently, and that depth reversal of ambiguous figures took more time when subjects were lying on their side or supine compared to upright, thus suggesting that the gravitational reference plays a significant role in these “visual” illusions. The structure of images, our representation of the environment, and orientation relative to gravity are all integral parts in interpreting visual images. In a weightless environment where no gravitational reference can be used, it is expected that similar alterations in visual perception will occur.     

Predicting performance in manually controlled rendezvous and docking through spatial abilities

Manually controlled rendezvous and docking (manual RVD) is a challenging space task for astronauts. This study aims to identify spatial abilities that are critical for accomplishing manual RVD. Based on task analysis, spatial abilities were deduced to be critical for accomplishing manual RVD. 15 Male participants performed manual RVD task simulations and spatial ability tests (the object-manipulation spatial ability and spatial orientation ability). Participants’ performance in the test of visualization of viewpoints (which measures the spatial orientation ability) was found to be significantly correlated with their manual RVD performance, indicating that the spatial orientation ability in the sense of perspective taking is particularly important for accomplishing manual RVD.     

Spatial transformation of general sampling-aliasing frequency region for rotating-blade parameter identification with emphasis on single-probe blade tip-timing measurement

Blade-health monitoring is intensely required for turbomachinery because of the high failure risk of rotating blades. Blade-Tip Timing (BTT) is considered as the most promising technique for operational blade-vibration monitoring, which obtains the parameters that characterize the blade condition from recorded signals. However, its application is hindered by severe undersampling and stringent probe layouts. An inappropriate probe layout can make most of the existing methods invalid or inaccurate. Additionally, a general conflict arises between the allowed and required layouts because of arrangement restrictions. For the sake of economy and safety, parameter identification based on fewer probes has been preferred by users. In this work, a spatial-transformation-based method for parameter identification is proposed based on a single-probe BTT measurement. To present the general Sampling-Aliasing Frequency (SAFE) map definition, the traditional time–frequency analysis methods are extended to a time-sampling frequency. Then, a SAFE map is projected onto a parameter space using spatial transformation to extract the slope and intercept parameters, which can be physically interpreted as an engine order and a natural frequency using coordinate transformation. Finally, the effectiveness and robustness of the proposed method are verified by simulations and experiments under uniformly and nonuniformly variable speed conditions.     

超精密CNC平面磨床在线测量、补偿加工及对刀功能的自动化实现

介绍了大型超精密ＣＮＣ平面磨床测量控制系统设计中多传感器在线检测、导轨误差补偿加工以及超精密磨削对刀等特殊功能的实现方法,并将其纳入ＣＮＣ的Ｍ功能指令系统,实现了超精密平面磨削自动化     

求解TSP问题的遗传算法

无人侦察机的巡航问题,如果不考虑其它约束条件,实际上是一个 TSP 问题。目前还没有求解 TSP 问题的比较有效的实时算法,我们首先利用改良圈算法求得一个较好的初始种群,再应用遗传算法就可以实时地求得一个较满意的解。     

运载火箭起飞噪声环境缩比模型试验方法

基于相似理论建立缩比模型试验相似准则,提出了火箭发动机喷流声场试验预示方法的流程。通过缩比模型系留点火试验,根据几何相似、喷流参数相似、发射环境相似来预示起飞噪声环境,在国内首次给出了运载火箭表面的噪声环境的空间相关特性,结果表明预测结果与遥测数据之差小于1.5 dB,校验了缩比模型方法的有效性。缩比模型方法对于我国新一代运载火箭的起飞噪声环境预示、噪声载荷设计、地面试验具有重要意义。     

激光测高仪回波分解算法

开发了一种激光测高仪回波基本信息提取算法,对回波数据进行了高斯波分解,获取了高斯波分量的个数,及每个高斯波分量的波中心位置、宽度和幅度等参数．该算法首先根据回波拐点的数目和位置确定出高斯分量的个数及每个高斯分量的波中心位置和宽度初始值,随后利用线性最小二乘法计算出每个高斯分量的幅度,最后将经过选择和标记的高斯分量针对实际回波采用Levenberg-Marquardt方法进行拟合,得到优化后的高斯波基本参数．通过这些基本参数信息,能够进一步推导出激光测高仪光斑内各个反射表面的垂直分布、起伏程度和反射率等基本信息．