Statistical seismo-ionospheric precursors of M7.0+ earthquakes in Circum-Pacific seismic belt by GPS TEC measurements

The Circum-Pacific seismic belt is the region heavily affected by earthquakes in the world. The relationship between earthquake (e.g., the geographic location, occurrence time, magnitude, and focal depth) and ionospheric anomalies in the belt was investigated using 100 M7.0+ earthquakes during 2006–2015. The ground-based GPS measurements and global ionosphere map (GIM) data were used for the analyses of the ionospheric variations preceding the earthquakes. The results indicated that the occurrence rate of total electron content (TEC) anomalies was proportional to the magnitude and inversely proportional to the focal depth to a certain degree, and the occurrence frequency of anomalies had a rising trend with the days getting close to the main shock. The occurrence rate of TEC anomalies in the Southern hemisphere was larger than that in the Northern hemisphere. Besides, the spatial characteristics of TEC anomalies showed that the anomalies in low-middle latitudes did not coincide with the epicenter, sometimes the anomalies were also observed in the corresponding conjugated region. However, the TEC anomalies in the high latitude usually appeared around the epicenter and within the seismogenic zone while no TEC anomalies appeared in the conjugated area. These results may have potential applications to the earthquake prediction in the Circum-Pacific seismic belt.     

大型充液卫星在轨模式识别

提出了大型充液卫星在轨模式识别的方法 ,通过大型充液卫星在轨飞行试验确定液体晃动阻尼 ,为控制系统设计中确定晃动阻尼提供最可靠的依据     

基于U-net的紫外极光观测极光卵形态提取

极光卵形态提取是极光研究的重要手段.如何提高强干扰背景下的紫外极光图像极光卵形态提取精度,目前仍是一个难题.本文提出一种基于深度学习语义分割模型U-net的方法,实现了对极光卵形态的高精度提取.在Polar卫星紫外极光观测数据的实验结果表明,该方法相比于已有算法精度更高,对完整型极光卵和缺口型极光卵图像均能得到更加精确的提取结果,特别是针对强日辉干扰、灰度不均匀和对比度低情况下的紫外极光图像时,该方法显示了明显优势.     

基于PHM的航空装备可用度影响因素分析方法

对已有的航空装备可用度分析方法进行了综述,将航空装备可用度影响因素分为三类.通过PHM(Prognostics and Health Management)技术对航空装备保障过程的影响分析,梳理了基于PHM的航空装备可用度影响因素,并将这些因素按照其来源分为使用影响因素和设计影响因素两大类.给出了4个合理的仿真假设条件以简化仿真过程,并进一步将设计影响因素分为5种,并结合一个实例给出了基于PHM的航空装备可用度影响因素仿真过程中的输入.提出给定装备系统及其保障系统参数条件下的稳态可用度为仿真的输出,并给出与仿真输入相符的解析计算公式.详细描述了仿真程序的构成及其流程图.最后,以图形的方式给出了仿真结果,给出了案例的单因素分析及多因素耦合分析的过程及结论,验证了所提出的分析方法的可行性.      

可重构履带机器人的机构设计与控制方法实现

开发了用于完成复杂地形侦察作业的可重构履带机器人.从可重构机器人的特点出发,研究了模块化的机械电气结构和控制方法实现.设计实现的可重构机器人由4个基础运动模块,3个连杆模块和2个转动关节模块组成,通过各个模块的不同组合形式,实现了机器人构型的可重构.系统采用分布式控制体系,研究实现了机械构型发生改变时,基于ARM(Advanced RISC Microprocessor)的实时嵌入式控制系统的可重构.通过模拟楼宇内房间侦察作业,验证了可重构履带机器人具备复杂地形环境适应能力和简单方便的可重构性能.     

机翼／外挂颤振主动抑制实验研究

介绍了机翼/外挂系统颤振主动抑制实验的全过程,包括对于模型固有动特性的实验分析、颤振主动抑制系统的调试、以及风洞实验三个阶段。风洞实验在3m×3m低速风洞进行。实验目的是对基于三种不同原理设计的控制律进行验证,并对颤振主动抑制系统进行实验研究。结果表明:所设计的控制律能有效地抑制颤振。经实验验证,控制律的理论计算与实验结果相符。实验系统工作可靠,重复性好。     

气动弹性系统的阵风减缓与颤振主动抑制

针对Ｊ８飞机模型，研究了阵风减缓与颤振主动抑制的综合控制问题，应用现代控制理论设计控制系统，分别对机翼／外挂系统模型作开环和闭环分析。由数字式控制实现了阵风减缓与颤振主动抑制的风洞实验，风洞实验结果表明：设计控制律具有抑制颤振和减缓阵风响应的双重功能。     

CAS-1 lunar soil simulant

Lunar soil simulant is a geochemical reproduction of lunar regolith, and is needed for lunar science and engineering researches. This paper describes a new lunar soil simulant, CAS-1, prepared by the Chinese Academy of Sciences, to support lunar orbiter, soft-landing mission and sample return missions of China’s Lunar Exploration Program, which is scheduled for 2004–2020. Such simulants should match the samples returned from the Moon, all collected from the lunar regolith rather than outcrops. The average mineral and chemical composition of lunar soil sample returned from the Apollo 14 mission, which landed on the Fra Mauro Formation, is chosen as the model for the CAS-1 simulant. Source material for this simulant was a low-Ti basaltic scoria dated at 1600 years from the late Quaternary volcanic area in the Changbai Mountains of northeast China. The main minerals of this rock are pyroxene, olivine, and minor plagioclase, and about 20–40% modal glass. The scoria was analyzed by XRF and found to be chemically similar to Apollo 14 lunar sample 14163. It was crushed in an impact mill with a resulting median particle size 85.9 μm, similar to Apollo soils. Bulk density, shear resistance, complex permittivity, and reflectance spectra were also similar to Apollo 14 soil. We conclude that CAS-1 is an ideal lunar soil simulant for science and engineering research of future lunar exploration program.     

原子氧对航天器用有机热控涂层影响的研究

以在我国某型号卫星上应用的两种有机热控涂层——改进型S781铝灰漆和S956灰漆作为对象，首次就近地轨道原子氧环境对涂层性能（太阳吸收比αS和红外半球发射率εH）的影响进行实验研究。实验中采用同轴源原子氧装置，以近地轨道原子氧通量条件对涂层进行试验。结果表明，原子氧对涂层表面的侵蚀作用是造成涂层性能退化的主要原因，在相同的原子氧剂量下，涂层性能变化的程度与涂层组成成分的配比有关。     

卫星定位导航算法研究中卫星运动参数及导航星选取的仿真

在卫星定位导航系统的定位算法研究过程中，导航卫星星座中各卫星的运动参数，包括位置和速度参数，是进行研究的基础。因此在这一过程中，必须根据需要生成仿真卫星运动参数。针对定位卫星星座的特点，推导了适用于进行算法研究的导航卫星运动参数的仿真公式。在此基础上，依据卫星定位用户工作的方式特点，给出了一种判断用户机可视卫星的公式。作为算例，最后给出了以ＧＰＳ参数为基础的导航卫星星座运动参数的仿真结果