Phased array of large reflectors for deep-space communication

In this paper the problem of uplink array calibration for deep-space communication is considered. A phased array of many modest-size reflectors antennas is used to drastically improve the uplink effective isotropic radiated power of a ground station. A radar calibration procedure for the array phase distribution is presented using a number of in-orbit targets. Design of optimal orbit and the number of calibration targets is investigated for providing frequent calibration opportunities needed for compensating array elements phase center movements as the array tracks a spacecraft. Array far-field focusing based on the near-filed in-orbit (low Earth orbit (LEO)) calibration targets is also presented and array gain degradation analysis based on the position error of the array elements and in-orbit targets has been carried out. It is shown that errors in the in-orbit targets positions significantly degrade the far-field array gain while the errors in array elements positions are not very important. Analysis of phase errors caused by thermal noise, system instability, and atmospheric effects show insignificant array gain degradation by these factors     

The Pre-CME Sun

The coronal mass ejection (CME) phenomenon occurs in closed magnetic field regions on the Sun such as active regions, filament regions, transequatorial interconnection regions, and complexes involving a combination of these. This chapter describes the current knowledge on these closed field structures and how they lead to CMEs. After describing the specific magnetic structures observed in the CME source region, we compare the substructures of CMEs to what is observed before eruption. Evolution of the closed magnetic structures in response to various photospheric motions over different time scales (convection, differential rotation, meridional circulation) somehow leads to the eruption. We describe this pre-eruption evolution and attempt to link them to the observed features of CMEs. Small-scale energetic signatures in the form of electron acceleration (signified by nonthermal radio bursts at metric wavelengths) and plasma heating (observed as compact soft X-ray brightening) may be indicative of impending CMEs. We survey these pre-eruptive energy releases using observations taken before and during the eruption of several CMEs. Finally, we discuss how the observations can be converted into useful inputs to numerical models that can describe the CME initiation.     

仿真与响应曲面法的结合及其在综合生产计划中的应用

 论述响应曲面法与仿真相结合的优化结构,着重讨论了一阶和二阶响应曲面的仿真拟合原理和寻优过程,从而可在仿真环境下给出最优决策参数。利用所开发的GASPRSM仿真优化软件,对飞机工厂生产计划安排进行了仿真运行,证明可以取得显著的经济效果。     

基于Riccati方程的离散容错控制系统设计

基于离散系统的Ｒｉｃｃａｔｉ方程，提出一种对传感器失效具有完整性的离散控制系统的设计方法，给出了完整性设计方法的设计步骤，并用设计实例验证了该方法的有效性．该方法还可推广用于执行器失效的情况．     

流变铸造法制备Al_2O_（3P）／ZA4－3复合材料的研究

为提高模用锌合金ＺＡ４－３的性能，扩大其应用范围，本项工作采用流变铸造法成功地制备了性能稳定的Ａｌ２Ｏ３Ｐ／ＺＡ４－３复合材料。对该材料进行了弯曲强度、冲击韧性、压缩强度、硬度及耐磨性等性能试验，结果表明：Ａｌ２Ｏ３ｐ的加入，使锌合金的压缩强度、室温和高温硬度以及耐磨性明显提高，其弯曲强度略有降低，而其冲击韧性下降了　。最后还讨论了成形工艺参数、颗粒含量和颗粒直径对该复合材料性能的影响。     

机场跑道耐冲磨混凝土的研究

针对机场跑道混凝土所处环境、受力特环以及对修补材料的性能要求，提出采用超塑化、膨胀、树脂掺入等复合手段，大幅度改善钢纤维混凝土基质材料的结构性能。通过高效粘结，充分发挥了钢纤维的增韧抗冲击作用，使这种有机无机复合、金属非金属复合的混凝土材料具有优异的抗冲击性和耐磨性。实验结果表明，机场跑道混凝土特别是飞机起降区域板块适合采用SPE－SFRC复合材料。在基础稳定的条件下，基本可在设计使用年限内无须大修，其社会、经济效益巨大。     

基于立体视觉的孔探分析系统及其应用

孔探分析在现代航空发动机故障诊断中一直发挥着重要的作用，开发基于立体视觉的孔探分析系统，对提高故障诊断水平和预测准确度，节约发动机维护成本有着重要的现实意义，系统利用立体视觉技术以及图像处理技术，完成了对双目视觉左右图像的标定和匹配，实现了对实体表面的三维测量和立体重建，本文介绍了基于立体视觉的孔探分析系统的基本原理与主要功能，并结合应用实例验证了系统的有效性。     

铝合金薄板焊接热裂敏感性探索

探讨了用钨极氩弧焊焊接铝合金ＬＹ１２ＣＺ及ＬＹ１２Ｍ薄板时其热裂纹的变化规律，并分析了焊接工艺参数及填充材料对热裂纹的影响。试验结果表明，选择合适的工艺参数和填充材料可以明显提高该类合金的抗裂性能。     

三维CT图象自动分割法

计算机断层扫描图象（ＣＴ）和核磁共振图象（ＭＲＩ）是诊断疾病和制定治疗方案与手术方案的主要依据之一，而分割ＣＴ和ＭＲＩ图象是定量分析其平面与三维信息的关键之一。本文先采用三维自适应滤波，在保留图象细节的前提下滤除高斯分布噪声和脉冲噪声，然后根据ＣＴ或ＭＲＩ各断层多阈值二值化图象采用区域自动增长算法实现了三维ＣＴ图象和ＭＲＩ图象的自动分割。最后给出了腹部ＣＴ图象的分割结果，该方法分割精度高，速度快，具有广泛的临床应用价值     

目标电磁散射特性的混合法研究

从Ｓｔｒａｔｔｏｎ－Ｃｈｕ公式出发，利用阻抗边界条件，得出阻抗边界条件积分方程，将目标表面分成不同的区域，有些区域用高频解析方法求出其表面电流，有些区域利用矩量法解阻抗边界条件积分方程得表面电流。本文以橄榄体（包括介质涂敷情形）为例，计算其电磁散射特性，混合法计算结果与实测结果或其他方法的计算结果比较吻合。