高精度非接触磁浮机构设计及其输出特性测试研究

为验证"双超"卫星地面试验系统与地面验证方案的合理性、可行性,针对"双超"卫星平台的核心部件非接触磁浮机构,提出了一种非接触磁浮机构磁钢匀强磁场、激励线圈拓扑结构及高精度程控精密功率放大器的多参数综合优化设计与测试方法。首先,通过选择适宜的磁钢材料和设计磁钢结构尺寸参数实现非接触磁浮机构磁钢磁场的均匀性;其次,通过激励线圈参数优化可降低输出力的波动;再次,通过驱动电路的优化设计可提升程控精密功率放大器的输出电流精度;最后,通过非接触磁浮机构的输出特性测试,验证了设计方法的有效性。该方法将"双超"平台的需求分解成磁浮机构各部分的设计指标,简化明确了设计思路,方案通过验证为下一步"双超"平台原理样机的设计及未来"双超"平台的工程应用提供了技术支撑。     

攻角引起的高超声速进气道不起动/再起动特性分析

起动/不起动是高超声速进气道的重要流动现象,其影响进气道的工作范围和再起动能力.首先对典型的高超声速进气道二维流场进行了数值模拟,对攻角变化引起的高超声速进气道不起动/再起动过程进行了研究.从流动稳定性的角度阐述了高超声速进气道不起动/再起动特性形成的原因,分析了高超声速进气道不起动/再起动过程中进气道性能参数随来流攻角的变化规律,最后对进气道的再起动条件进行了讨论.      

光阻法测量油液中颗粒污染度的研究

光阻法颗粒计数器是利用颗粒对光的消光作用来实现对颗粒的计数功能。提出了利用光阻法来测量油液颗粒污染度的方法 ,着重介绍了光阻法测量油液污染度的工作原理、测量系统及其工作特点。     

基于FPGA的高速串行传输接口研究与实现

介绍了FPGA最新一代器件Virtex-5上的高速串行收发器RocketIO.基于ML505开发平台构建了一个高速串行数据传输系统,重点说明了该系统采用RocketIO实现1.25Gbps高速串行传输的设计方案.实现并验证了采用FPGA完成千兆串行传输的功能目标,为后续采用FPGA实现各种高速协议奠定了良好的基础.     

太阳系边际探测飞行任务规划

针对太阳系边际探测任务,开展了星际多目标飞越的任务规划,采用小推力混合优化设计方法完成了基于借力飞行及电推进技术的行星际转移轨道联合优化设计,对比研究了面向日球层鼻尖和尾部探测的星际多目标探测飞行方案。研究表明,探测器在2024-2025年发射,可飞抵日球层鼻尖区域,在2027-2030年发射可飞抵日球层尾部区域,并可在2049年1月1日前飞离日心100 AU,实现太阳系边际空间的科学探测。其中日球层鼻尖探测任务探测器飞抵100 AU的位置位于鼻尖中心区域,可与旅行者1号、2号探测器形成有效互补。文章所用任务规划方法,可为太阳系边际探测的自主任务规划技术提供基础,相关研究成果能够为未来中国首次太阳系边际探测任务的实施提供有价值的参考。     

Time delay of ionospheric TEC storms to geomagnetic storms and pre-storm disturbance events in East Asia

Using the TEC data at Beijing (39.61°N, 115.89°E)/Yakutsk (62.03°N, 129.68°E) stations of East Asia regions and relevant geomagnetic data from 2010 to 2017, we have studied the time delay of ionospheric storms to geomagnetic storms and compare it with our previous results of Taoyuan (25.02°N, 121.21°E) station (Zhang et al., 2020). The data shows a well-known local time dependence of the time delay, and seasonal dependences are different at these stations. In addition, there is no correlation between the time delay and the magnetic storm intensity /solar activity, except the time delay of negative storms has weakly negative dependence on the solar activity. Comparing with the results of Taoyuan station which is located at EIA region in East Asia, we find that the time delay increases nonlinearly as the latitude decreases due to different ionospheric backgrounds at these places. Moreover, the pre-storm disturbance events are found to have similar statistical characteristics as the pre-storm enhancement in Europe middle latitudes (Bure?ová and La?tovi?ka, 2007). By subtracting the common features of the pre-storm disturbance events, we preliminarily infer that auroral activity might be main driver of the pre-storm disturbance events.     

Experimental study of curvature effects on jet impingement heat transfer on concave surfaces

Experimental study of the local and average heat transfer characteristics of a single round jet impinging on the concave surfaces was conducted in this work to gain in-depth knowledge of the curvature effects. The experiments were conducted by employing a piccolo tube with one sin-gle jet hole over a wide range of parameters: jet Reynolds number from 27000 to 130000, relative nozzle to surface distance from 3.3 to 30, and relative surface curvature from 0.005 to 0.030. Exper-imental results indicate that the surface curvature has opposite effects on heat transfer characteris-tics. On one hand, an increase of relative nozzle to surface distance (increasing jet diameter in fact) enhances the average heat transfer around the surface for the same curved surface. On the other hand, the average Nusselt number decreases as relative nozzle to surface distance increases for a fixed jet diameter. Finally, experimental data-based correlations of the average Nusselt number over the curved surface were obtained with consideration of surface curvature effect. This work con-tributes to a better understanding of the curvature effects on heat transfer of a round jet impinge-ment on concave surfaces, which is of high importance to the design of the aircraft anti-icing system.     

C/C++软件的危险函数静态检查研究

C/C++软件开发过程中,源代码中若使用了危险函数,会造成内存缓冲区溢出,产生严重的安全漏洞和隐患,因此对源代码进行危险函数检查非常重要.对于大型软件模块需要将危险函数静态检查工具集成到持续集成工具上,对源代码进行危险函数检测.结合工作实践,介绍了危险函数检测工具,叙述了对源代码进行检查的流程;详细叙述了基于持续集成的危险函数检查过程;最后介绍了两个典型案例.工作实践表明,进行危险函数检查有助于及时发现和处理软件中的危险函数隐患,从而提高软件产品的质量和安全性.     

The OSIRIS-REx Visible and InfraRed Spectrometer (OVIRS): Spectral Maps of the Asteroid Bennu

The OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) is a point spectrometer covering the spectral range of 0.4 to 4.3 microns (25,000–2300 cm^?1). Its primary purpose is to map the surface composition of the asteroid Bennu, the target asteroid of the OSIRIS-REx asteroid sample return mission. The information it returns will help guide the selection of the sample site. It will also provide global context for the sample and high spatial resolution spectra that can be related to spatially unresolved terrestrial observations of asteroids. It is a compact, low-mass (17.8 kg), power efficient (8.8 W average), and robust instrument with the sensitivity needed to detect a 5% spectral absorption feature on a very dark surface (3% reflectance) in the inner solar system (0.89–1.35 AU). It, in combination with the other instruments on the OSIRIS-REx Mission, will provide an unprecedented view of an asteroid’s surface.     

10 cm ECR中和器性能优化实验研究

针对电子回旋共振(ECR)中和器性能无法满足实际应用需求的问题，开展了10 cm ECR中和器的性能优化实验研究，在分析现有ECR中和器内部结构的基础上，提出新的结构改进方案。通过改进ECR中和器的电子束流引出对比实验，得到了中和器结构对束流引出性能的影响规律。优化后的ECR中和器性能实验表明：相同条件下ECR中和器束流引出大小与气体流量大小不成正相关，但随着微波功率的增加而增加。性能实验得到的中和器最佳工作和性能参数为：微波功率为10 W、氙气流量为0.5 sccm，收集板间距为5 mm时，在50 V引出电压条件下能够引出127 mA的电子束流。