数据传输卡插拔互换性技术探讨

介绍了数据传输卡(DTC)插拔互换性技术有关的几个问题。在产品有使用延续性要求的限制下,在不提高原零部件制造精度和不改变原装配方式的条件下,提出了按照模拟量传递原则而建立的标准体系——装配检验对合平台,并以此在生产中实施,满足了产品使用互换性要求。同时提出了一种新型弹顶组件的设计,使弹顶位置更合理,弹顶更可靠,从而进一步提高了产品插拔可靠性。     

采用二维贝叶斯方法求解旋转盘腔导热反问题

为了研究压气机旋转盘腔换热特性,实现准确求解转盘表面传热系数,引入二维贝叶斯方法,此方法采用先验分布优化测温误差,并且更加符合转盘的二维特性。通过加入噪声的模拟数据验证方法的可行性,结果表明无测温误差时方法的平均误差是3.2%,有测温误差时方法的平均误差是10.6%,并分析了误差来源。通过与已有实验结果对比,发现方法更适用于计算转盘迎风面与背风面传热差异较大时的表面传热系数,平均相对误差为9.6%,满足实际工程精度的要求。通过改变盘面温度测点数量,发现测点增加会提升计算精度,并采用统计抽样理论分析原因,发现在可接受误差为10%时,所需要的测点数量比较合理。     

利用随机森林算法的卫星控制系统故障诊

针对卫星姿态控制系统存在闭环控制，外部干扰强，进而影响故障诊断准确性和实时性的问题，提出了一种利用随机森林算法的卫星姿态控制系统姿态敏感器和执行器故障诊断方法。首先，采集不同故障情形下卫星姿态控制系统的输入输出数据，进行特征提取。随后通过随机有放回抽样划分训练集和测试集，建立基于随机森林算法的故障诊断模型。利用生成的随机森林模型，对实时输入输出数据进行分类，实现卫星姿态控制系统的故障诊断。利用卫星姿态控制系统半物理仿真平台的数据进行实验，对比实验结果表明：本文所提方法可以实现故障高精度分离，并具有更好的实时性，适用于卫星姿态控制系统的故障诊断问题。     

锂离子电池单离子导体聚合物电解质研究进展

锂离子电池在3C电子产品和动力汽车电池行业广泛应用,在航天电源领域也展现出一定的前景。单离子导体是基本仅由参与电化学反应的锂离子迁移的电解质体系,解决传统锂离子电池液态电解质存在的副反应和阴离子的浓差极化等问题,改善电池的库伦效率和循环寿命。研究者们发展了多种类型的单离子导体电解质。本文总结了近5年来不同阴离子类型的单离子导体聚合物电解质合成策略以及分子动力学模拟计算的最新进展。     

Performance analysis of PPP ambiguity resolution with UPD products estimated from different scales of reference station networks

Integer ambiguity fixing with uncalibrated phase delay (UPD) products can significantly shorten the initialization time and improve the accuracy of precise point positioning (PPP). Since the tracking arcs of satellites and the behavior of atmospheric biases can be very different for the reference networks with different scales, the qualities of corresponding UPD products may be also various. The purpose of this paper is to comparatively investigate the influence of different scales of reference station networks on UPD estimation and user ambiguity resolution. Three reference station networks with global, wide-area and local scales are used to compute the UPD products and analyze their impact on the PPP-AR. The time-to-first-fix, the unfix rate and the incorrect fix rate of PPP-AR are analyzed. Moreover, in order to further shorten the convergence time for obtaining precise positioning, a modified partial ambiguity resolution (PAR) and corresponding validation strategy are presented. In this PAR method, the ambiguity subset is determined by removing the ambiguity one by one in the order of ascending elevations. Besides, for static positioning mode, a coordinate validation strategy is employed to enhance the reliability of the fixed coordinate. The experiment results show that UPD products computed by smaller station network are more accurate and lead to a better coordinate solution; the PAR method used in this paper can shorten the convergence time and the coordinate validation strategy can improve the availability of high precision positioning.     

基于PCA聚类机场跑道利用率研究分析

机场跑道利用率低一直是制约机场运行效率的主要因素之一.为找出机场跑道利用率低的机场,首先运用数据挖掘的方式,结合国内外相关研究,找到一套适合机场跑道利用率的评价指标体系,利用主成分聚类分析方法,建立基于主成分聚类分析下机场跑道聚类结果;其次对聚类分析得到的相关图表加以说明,并揭示各大机场跑道利用状况的发展趋势并加以分析.结果表明:PCA聚类分析优于聚类分析,具有一定实用性.     

Bipartite graph-based control flow checking for COTS-based small satellites

Single event upset(SEU)effect,caused by highly energized particles in aerospace,threatens the reliability and security of small satellites composed of commercial-off-the-shelves(COTS).SEUinduced control flow errors(CFEs)may cause unpredictable behavior or crashes of COTS-based small satellites.This paper proposes a generic software-based control flow checking technique(CFC)and bipartite graph-based control flow checking(BGCFC).To simplify the types of illegal branches,it transforms the conventional control flow graph into the equivalent bipartite graph.It checks the legality of control flow at runtime by comparing a global signature with the expected value and introduces consecutive IDs and bitmaps to reduce the time and memory overhead.Theoretical analysis shows that BGCFC can detect all types of inter-node CFEs with constant time and memory overhead.Practical tests verify the result of theoretical analysis.Compared with previous techniques,BGCFC achieves the highest error detection rate,lower time and memory overhead;the composite result in evaluation factor shows that BGCFC is the most effective one among all these techniques.The results in both theory and practice verify the applicability of BGCFC for COTS-based small satellites.     

民用飞机翼身整流罩区域温度场分析研究及影响

现代民用飞机机身结构大量采用复合材料,但因其遇到高温时会变软,耐热性较差,这就对复合材料周围的环境温度提出了新的要求。以某型飞机的空调组件安装区域进行温度场CFD计算,分析了安装区内的高温部件对机身复合材料结构的影响。为了防止机身复合材料被高温部件烫伤,在高温部件的上方安装隔热板同时进行局部通风冷却,并对相应的工况进行CFD计算对比。