太阳同步轨道卫星交点地方时漂移估算方法研究

根据我国第一代极轨气象卫星“风云一号”C(FY-1C)星轨道实际观测值，分析了太阳_同步轨道卫星轨道漂移的一般规律，提出了一种简便有效的卫星交点地方时漂移估算方法，并用FY-1C星实际的交点地方时漂移量，对该方法进行了分析和改进。     

构造含结点旋转单元的坐标变换法

Ａｌｌｍａｎ提出了带角结点旋转的三角形单元及相应的四边形单元，法向位移的二次插值保证了该单元的精度，但带来了构成单元的复杂。本文把Ａｌｌｍａｎ单元看成是对一个有边中结点单元进行坐标变换的结果，大大提高了计算效率。     

近代烃类转化用换热转化器的开发与应用

汇集国内外开发的新型换热转化器(亦称转化炉)的设计形式和结构特征,可供老厂节气节能挖潜技术改造或新建装置优选和参考。     

Design and implementation of five-axis transformation function in CNC system

To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle- tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP （rotation tool center point control） and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software struc- ture, the instructions with respect to the cutter＇s position and orientation can be directly carried out in the CNC system.     

天/地基多平台空间目标光电观测时效性分析

针对如何部署光学探测设备才能更好实现对空间目标的高精度高频度监视问题,考虑光照条件、相对关系及探测性能,构建了天/地基空间目标探测与成像仿真模型;按照轨道特征选取了94颗LEO（Low Earth Orbit,低地球轨道）卫星、63颗GEO（Geosynchronous Earth Orbit,地球同步轨道）卫星和18颗大椭圆轨道卫星,选用春夏秋冬典型季节的特定时间长度,仿真分析了国内地基、南北极科考站、LEO卫星、准GEO卫星等多平台光电手段的位置探测和成像观测能力;比对分析地基平台纬度和季节、天基平台轨道高度和倾角对探测能力的影响得出：南北极科考站相比于国内站点可提高重点季节的探测时效性,98°倾角LEO平台对低轨目标成像时效性方面更具优势,等.在此基础上,提出了我国空间目标光电观测设备天地一体的布局构想.     

Reliability analysis based on a novel density estimation method for structures with correlations

Estimating the Probability Density Function (PDF) of the performance function is a direct way for structural reliability analysis,and the failure probability can be easily obtained by integration in the failure domain.However,efficiently estimating the PDF is still an urgent problem to be solved.The existing fractional moment based maximum entropy has provided a very advanced method for the PDF estimation,whereas the main shortcoming is that it limits the application of the reliability analysis method only to structures with independent inputs.While in fact,structures with correlated inputs always exist in engineering,thus this paper improves the maximum entropy method,and applies the Unscented Transformation (UT) technique to compute the frac tional moments of the performance function for structures with correlations,which is a very efficient moment estimation method for models with any inputs.The proposed method can precisely estimate the probability distributions of performance functions for structures with correlations.Besides,the number of function evaluations of the proposed method in reliability analysis,which is determined by UT,is really small.Several examples are employed to illustrate the accuracy and advantages of the proposed method.     

An experimental method for squealer tip flow field considering relative casing motion

Squealer tip is widely used in turbines to reduce tip leakage loss. In typical turbine environment, the squealer tip leakage flow is affected by multiple factors such as the relative casing motion and the wide range of variable incidence angles. The development of experimental methods which can accurately model the real turbine environment and influencing factors is of great significance to study the squealer tip leakage flow mechanism. In the present paper, a low-speed turbine cascade test facility which can model the relative casing motion and wide range of variable incidence angles (−25° to 55°) is built. Based on the similarity criteria, a high-low speed similarity transformation method of the turbine cascade is established by considering the thickness of the turbine blade. A combined testing method of Particle Image Velocimetry (PIV) and local pressure measurement is proposed to obtain the complex flow structures within the tip cavity. The results show that the experimental method can successfully model the relative casing motion and the wide range of variable incidence angles. The low-speed cascade obtained by the similarity transformation can model the high-speed flow accurately. The measurement technique developed can obtain the complex flow field and successfully capture the scraping vortex within the squealer tip.     

Automatic extraction of lineaments based on wavelet edge detection and aided tracking by hillshade

Lineaments refer to the linear or curvilinear textures on remote sensing image, whose general spatial distribution characteristics are often the response of deep geological sturcture at the surface. Firstly, we use wavelet modulus maximum transformation to detect the edges with 4 scales on Landsat – 8 OLI B5 image and analyze their multi-scale characteristics. As the result, it is determined that the optimal scale of edge detection is 4, and the outline that consist of the edge pixels is roughly corresponding to the geological structure of mine area. Thus the incomplete lineaments have been extracted by using the 2D otsu algorithm. Secondly, the hillshade map generated based on DEM is processed to generate binarized linear shadow. Finally, the linear shadow is superimposed on the lineaments preliminarily extracted to obtain the optimized lineaments. Experiment results show that, based on the method, there are some deformation and displacement between the lineaments extracted and the actual geological structure, and it fail to effectively extract Qilinchang Fault, but lineaments are in good correspondence with Kuangshanchang Fault, Dongtou Fault and Niulan River Fault, which are basically in accord with the geological structure framework of the mine area.     

PCE方法在空间实验室轨道预报误差分析中的应用

应用多项式混沌展开法(PCE)进行空间实验室轨道预报误差分析。通过构建PCE模型对轨道预报的不确定性传播过程进行近似，进而对轨道预报后航天器位置和速度的误差进行分析。分析了不同PCE模型阶数、预报时长以及样本点的数目对构建PCE模型的影响。综合考虑精度和计算效率，给出了适用于空间实验室轨道预报误差分析的PCE模型。将PCE方法与传统方法进行对比，结果表明PCE方法有较好的非线性近似能力，且计算效率高，验证了PCE方法应用于空间实验室轨道预报误差分析的有效性。     

空间核动力平台电力管理系统的设计

空间核动力平台是一种全新的电源推进一体化航天器,其电力系统具有三相交流输出、工况多且复杂、母线电压体制多等特点。为了解决空间核动力平台负载供电诸多难题,通过对系统功能、负载类型、母线体制、组成配置、工作模式、控制机制等方面论证分析,提出了一种新型空间核动力平台电力管理系统架构。其中,变配电系统从硬件实现角度解决了基于布雷顿热电转换系统输出为负载稳态供电问题,自主控制系统从软件控制角度解决了主能源、辅助能源等多能源间流动控制以及负载暂态匹配问题,这为未来空间核动力平台电力管理系统研究工作奠定了基础。