Banach空间上非扩张映像的一个不动点定理

设X为满足Opial条件的自反Banach空间,D包含X为一闭星形集。证明了非扩张映像G：D→D的一个新的不动点定理,这一定理推广了已有相关结果。     

The role of ultraviolet imaging in studies of resolved and unresolved young stellar populations. M31 and M33

We discuss the relevance of UV data in the detection and characterization of hot massive stars and young stellar populations in galaxies. We show results from recent extensive surveys in M31 and M33 with Hubble Space Telescope (HST) multi-wavelength data including UV filters, which imaged several regions at a linear resolution (projected) of less than half a pc in these galaxies, and from GALEX far-UV and near-UV wide-field, low-resolution imaging of the entire galaxies. Both datasets allow us to study the hierarchical structure of star formation: the youngest stellar groups are the most compact, and are often arranged within broader, sparser structures. The derived recent star-formation rates are rather similar for the two galaxies, when scaled for the respective areas. We show how uncertainties in metallicity and type of selective extinction for the internal reddening may affect the results, and how an appropriate complement of UV filters could reduce such uncertainties, and significantly alleviate some parameter degeneracies.     

APS星敏感器太阳照射影响分析及试验验证

针对APS星敏感器在轨过程中太阳照射问题进行了研究,分析了太阳照射对星敏感器功能和性能的影响,设计了太阳照射相关的试验及验证方案,最后给出了相关试验过程和试验验证结果,明确了分析及试验结论.通过分析和试验结果表明:紫外辐照试验对光学系统透过率无明显影响,且影响在APS星敏感器灵敏度余量范围内;在轨太阳照射对APS星敏感器探测器及整机的功能和性能无影响.相关分析和试验数据可作为星敏感器后续改进设计的依据和参考.     

双星计划太阳电池壳降低磁场干扰的改进措施

文章通过试验和计算阐明“探测一号”卫星的周期性磁场干扰信号是来源于太阳电池壳,由于壳内表面的电流布线所致。通过对太阳电池壳背面电流走线方式进行改进,使改进后的“探测二号”卫星太阳电池壳的周期性变化磁场干扰有了很大程度的改善,达到了技术指标要求,保证了卫星飞行任务的圆满完成。     

根据同时观测信息确定航天器 姿态四元数的一种解析方法

介绍根据星敏感器同时观测几颗恒星的方向信息,用最小二乘法确定飞行器姿态的经典Wehba问题.针对用四元数描述飞行器姿态的情况,推导了的一种解析算法.观测5颗恒星实例的仿真结果表明,该算法能保证飞行器体轴系相对惯性系姿态的高精度.     

Athens Neutron Monitor Data Processing Center – ANMODAP Center

Cosmic ray measurements in Athens were initiated in November 2000 with a standard 6NM-64 neutron monitor. Within the last years an effort has been made in order to construct an effective database of neutron monitor (NM) and satellite data in real-time, regarding the necessities of space weather monitoring (Athens Neutron Monitor Data Processing Center – ANMODAP Center). The prospective goal of this network is to make possible the receiving of all data in real-time in close sequence from all servers around the globe. The graphical representation of all these data in real-time is available through the website of the station (http://cosray.phys.uoa.gr). Moreover, a second database that collects data with 1-min resolution operates in a parallel mode. The online services as a special ‘Alert’ algorithm for Ground Level Enhancements (GLEs) and some models created to analyze aspects of GLEs as the neutron monitor Basic Anisotropic Neutron Ground Level Enhancement (BANGLE) model and the Forbush Decreases (FORD) model as well, are presented. Moreover, a short account on work performed on the possible relationship between the geomagnetic activity level and the biological effects is given.     

惯性+星光折射定位组合导航技术研究

由于现有惯性器件精度水平有限,纯惯性导航误差较大,因此需要采用组合导航的方式来提高导航精度.目前,全自主组合导航方式中传统的惯性+星光定姿组合导航方法只能实现定姿,不能实现定位,无法修正加速度表测量误差引起的惯性导航误差,故在精度上可提升空间有限.为此,提出了一种惯性+星光折射定位组合导航方法,重点从星光折射定位原理、...     

An identification for GEMINGA: A review of all the available data

Dedicated X-ray, optical and radio observations aimed at the identification of the bright γ-ray source 2CG195+04 (GEMINGA) are presented. A very promising candidate is found and its properties are discussed in the context of possible astrophysical scenarios.     

羊八井宇宙线强度观测数据的气压修正

分析了羊八井宇宙线强度的气压修正，分析表明，气压修正不仅与气压有关，而且与太阳活动有关．太阳活动最高的年，气压修正系数的绝对值最大．此外，计数率的修正值还与数据采样的时间间隔有关，即使是同一时间段，不同时间间隔采用率得到的修正值是不同的．本文最后分析了西藏羊八井中子监测器观测数据的气压修正，得到单路及八道多重计数的气压修正系数．     

基于Delaunay三角剖分的全天自主星图识别算法

在地球物理建模中,Delaunay三角剖分因其对给定点集进行三角剖分具有剖分结果唯一性这一重要特点而得到广泛应用.采用Delaunay 剖分这一性质,首次将Delaunay剖分算法应用到星图识别中.利用全天球星图的剖分不变性,采用有界曲面剖分的边界递归法,生成有序且容量小的完备导航星库;利用二维Delaunay三角剖分对视场内恒星星图进行剖分,将其结果进行快速匹配识别.仿真实验结果表明与现有的星图识别算法相比,此算法具有高的识别率,良好的实时性和鲁棒性,且所需导航星库的容量小,检索速度快.