基于多级等压混合的引射器参数匹配与优化

匹配和优化多级等压混合引射器的各项参数,得到理想的引射器增压比和引射效率,目的是提高多级等压混合引射器性能。通过数学分析和实验,研究了单级引射器参数变化对性能的影响,明确了多级等压混合引射器级数的确定原则,对影响单级引射器性能的参数在多级中进行了匹配和优化,表明引射马赫数、被引射气体温度、单级引射器引射系数和增压比匹配与优化后,能显著提升多级等压混合引射器性能。     

基于TMSDG的民用飞机故障诊断隔离策略

 针对民用飞机排故时交互式故障诊断与隔离需求,在符号有向图(SDG)中补充状态节点的故障概率信息和未测状态表达,引入对测试节点的描述,提出了一种附带测试维修信息的SDG(TMSDG),给出了基于此模型的交互诊断流程。首先根据初始征兆获取可疑集,然后综合可靠性和测试代价等因素生成一种基于最小测试代价的诊断二叉树对初始可疑集进一步隔离。该模型能描述复杂系统中存在的状态关联和故障测试依赖关系,对其中故障进行交互式诊断和隔离指导。利用该方法建立了某飞机发动机高压引气的诊断模型,实验结果表明提出的方法有效。该方法适用于飞机的外场故障诊断与隔离。     

Turbulence, Magnetic Reconnection in Turbulent Fluids and Energetic Particle Acceleration

Turbulence is ubiquitous in astrophysics. It radically changes many astrophysical phenomena, in particular, the propagation and acceleration of cosmic rays. We present the modern understanding of compressible magnetohydrodynamic (MHD) turbulence, in particular its decomposition into Alfvén, slow and fast modes, discuss the density structure of turbulent subsonic and supersonic media, as well as other relevant regimes of astrophysical turbulence. All this information is essential for understanding the energetic particle acceleration that we discuss further in the review. For instance, we show how fast and slow modes accelerate energetic particles through the second order Fermi acceleration, while density fluctuations generate magnetic fields in pre-shock regions enabling the first order Fermi acceleration of high energy cosmic rays. Very importantly, however, the first order Fermi cosmic ray acceleration is also possible in sites of magnetic reconnection. In the presence of turbulence this reconnection gets fast and we present numerical evidence supporting the predictions of the Lazarian and Vishniac (Astrophys. J. 517:700–718, 1999) model of fast reconnection. The efficiency of this process suggests that magnetic reconnection can release substantial amounts of energy in short periods of time. As the particle tracing numerical simulations show that the particles can be efficiently accelerated during the reconnection, we argue that the process of magnetic reconnection may be much more important for particle acceleration than it is currently accepted. In particular, we discuss the acceleration arising from reconnection as a possible origin of the anomalous cosmic rays measured by Voyagers as well as the origin cosmic ray excess in the direction of Heliotail.     

空空导弹仿真环境的构建

导弹的仿真试验是导弹挂飞和靶试前的关键性试验,是判断导弹是否具备试飞条件的重要工程依据.本文介绍的空空导弹仿真试验环境,可以在试验室条件下完成导弹的工作流程,为雷达型空空导弹的半实物仿真提供了重要的支撑平台     

红外热像检测技术在吸波涂层缺陷研究中的应用

采用红外热像技术探索了一种吸波材料脱粘缺陷无损检测的方法。在铝合金基材上制备具有不同脱粘缺陷的吸波材料。采用红外热像检测系统监测热激励后材料样品表面的温度变化。通过对热图像和温度变化数据的分析,获得材料表面或缺陷的特征。试验表明这一方法可以有效地检测出铝合金基材上铁磁性吸波涂层脱粘缺陷,测量简便、结果直观,对涂层无损坏,可以实现吸波涂层施工中吸波涂层质量和使用过程中涂层可靠性的监控。     

热处理制度对1Cr16Ni2MoN钢组织和性能的影响

通过试验研究了不同热处理制度对1Cr16Ni2MoN钢的金相组织、室温拉伸、冲击性能、硬度的影响.随淬火温度的提高,晶粒长大,570℃回火后的强度、塑性、韧性均增加,但660℃回火后的强度、塑性均下降;脆性温度区间为500℃左右;随1040℃保温时间的延长,略提高570℃回火后的强度,略降低660℃回火后的强度.合金优化的热处理工艺为:(a) 1030～ 1040℃×1h油冷+ 550～570×1 h空冷;(b) 1030 ～ 1040℃×1h油冷+650～ 670×1 h空冷.     

载人航天器热控分系统噪声控制

随着载人航天器越来越复杂,热控分系统所用到的高速旋转设备越来越多,所产生的噪声将影响航天员的身体健康,因此载人航天器的噪声控制非常迫切。文章通过热控分系统的布局设计以及单机设备的降噪优化等措施,找到了有效降低整个载人航天器热控分系统噪声水平的方法,可供类似的载人航天项目的热控设计参考。     

用于深层充电评估的卫星介质电导率测量技术研究

准确测量得到卫星介质材料的电导率对于卫星深层充电危害评估具有重要意义。在电荷贮存衰减法的基础上,文章提出了一种获得介质材料暗电导率和辐射诱导电导率的试验测量和数值计算方法,即采用90Sr-90Y β放射源,在温度为20 ℃、束流密度为5 pA/cm2的条件下对卫星常用的聚酰亚胺材料进行辐照试验,通过测得的材料表面电位随时间的变化曲线,拟合得到材料的暗电导率和辐射诱导电导率。该方法已在某卫星产品的充电评估中得到应用,计算结果与模拟试验结果符合较好。     

Experimental investigation on ice-breaking performance of a novel plasma striker

Aircraft icing has long been a plague to aviation for its serious threat to flight safety.Recently, researches about a newly proposed deicing method based on Plasma Synthetic Jet Actuator(PSJA) have just started. To meet the requirements of in-flight deicing, structure of PSJA needs to be adjusted. This paper completed the detailed design and experimental validation of a novel plasma striker, which was a modified version of PSJA. Influences of mass of the moving part and rod shapes on the ice-br...     

一种辐射噪声源快速重构与机理描述方法

针对现有辐射电磁兼容标准测试方法仅能得到辐射总噪声,而无法诊断辐射噪声机理,利用盲源信号分离算法进行辐射噪声源分析与定位,并结合近场波阻抗理论实现辐射噪声机理诊断。理论与实验结果表明,采用文中方法可提取辐射噪声源特性,抑制辐射噪声,并通过GB 9254 Class B标准,从而验证方法的有效性。