基于Modelica的斜盘式轴向柱塞泵建模仿真研究

斜盘式轴向柱塞泵是典型机电液混合的复杂系统,故障隐蔽性强,缺乏基于实际机械结构的多领域仿真建模。本文开展了基于Modelica的斜盘式柱塞泵建模仿真研究。首先研究了实际某型柱塞泵机械结构参数,进行部件划分和组装建模,搭建了以斜盘式柱塞泵为核心的局部液压系统。然后针对柱塞泵常见的泄漏、压损、堵塞和气穴等故障模式,分别基于模型进行故障注入和定量仿真分析。明确了不同故障发生对液压系统造成的影响,充分验证了该模型对于柱塞泵常见故障问题仿真分析的可用性。该模型提高了斜盘式轴向柱塞泵多领域统一建模的精确性,为故障诊断和健康监测提供了参考。     

空空导弹研制风险分析中的模糊数学方法

 从软、硬件的成熟度、复杂度和依赖度对空空导弹研制的失败概率进行了评价,对研制失败在技术、进度和费用3方面造成的影响进行了分析。在以上分析的基础上给出了空空导弹研制风险评价的方法,以及用模糊数学的方法对评价结果进行处理的过程。最后给出空空导弹研制风险评价的实例。     

Statistical study of radio drifting pulsation structures with associated CMEs and other observations

Solar radio burst, especially the fine structures (FSs) and the drifting pulsation structures (DPSs), may be used as an important diagnostics tool to draw the evolution map of the flare loop in the initial phase of solar flares. In this work, 52 radio events were found accompanying with DPSs. They were all observed with the Solar Radio Spectrometers (0.625–7.6 GHz) of China during 1998–2004. Combining the radio observations with LASCO-C2, Goes-8 SXR, H_α, EUV and Trace observations, we analyzed all these events and obtained some statistic conclusions: First, 88% DPSs take place at the initial phase of the radio burst, and their rich spectrum characteristics are helpful to understand the events further. Second, 83% DPSs are associated with CMEs or ejection events, and all the events are accompanied by Goes SXR flare. Third, for CMEs and DPSs, which take the first step, there is no significant predominance of either of them. The relationship between the DPSs and CMEs is still not clear in this study because of the lack of spatial resolution in the centimeter–decimeter band. However, the EIT or Trace ejection happened during the onset/end time of DPSs. They are signatures of the initial phase of CMEs. Two events will be illustrated to explain this.     

平行度误差与虚拟基线场的构建

主要讨论在构建虚拟基线场的过程中所遇到的两反射镜面的平行度误差的影响问题,通过分析计算并前瞻可行的措施,在理论上证明了微小的平行度误差不会影响虚拟基线场的构建.     

空间环境对航天器影响的统计分析

概括介绍了空间环境的九个主要区域,归纳了它们对航天器各系统的影响。对114例各类环境造成的航天器失效和异常进行了统计分析,在此基础上对引起航天器失效、异常较多的四类空间环境进行了具体分析。     

紧急采购管理及风险库存控制模型

采购部门在日常事务中经常面临紧急采购的情况,以及随之而来的库存积压问题,这会给企业带来风险及库存成本的增加。在理论分析的基础上,通过是否设置风险库存的假设,建立两种对比模型,最后得出结论,设置风险库存的控制方法可以降低成本,并达到抵御风险的目的。     

扩展频谱技术在无人作战飞机通信系统中的应用

本文根据无人作战飞机的用途特点，从无人机的生存力角度出发（隐身通信），阐述了扩展频谱技术在其通信系统中的应用。     

一种叉齿式微硅加速度计的设计与分析

本文介绍了一种适合军民两用市场的、中低精度的叉齿式微硅加速度计的设计和仿真 ,其敏感轴平行于检测质量平面 ,微结构梁采用了折叠梁结构。对这种加速度计的结构参数进行了理论设计和优化选择 ,利用Ansys结构分析软件重点研究了折叠梁结构参数对加速度计固有谐振频率和力学特性的影响。最后给出了一个符合仪表性能要求的微加速度计 ,其中心摆片大小为 1.6 mm× 1.0 mm ,量程为 2 5 g,分辨率为 0 .5× 10 - 3g。     

The present and the future of random signal radars

The 30+ year development of random signal radar (RSR) is described in this paper. Conventional methods of implementing RSRs are summarized: correlation, spectrum analysis, and anti-correlation. Some typical RSR systems are introduced; for example: noise frequency modulation continuous wave radar; and random binary phase-coded continuous wave radar, and their merits and demerits are also pointed out. Finally, the development trends of RSR is analyzed