新型通用进气道类复杂腔体结构电磁散射计算方法

 利用Unigraphics（UG）内部基于非均匀有理B样条（NURBS）的建模技术,采用UG二次开发,实现了在任意腔体中射线路径准确追踪,寻迹效率较高。提出一种射线追踪的新方法,解决了传统弹跳射线法（SBR）确定射线路径困难、精度不高和效率较低的问题。在此新方法基础之上开发了可以计算任意形状进气道类复杂电大腔体及角形结构雷达散射截面（RCS）的计算软件,实现了腔体建模与RCS计算的无缝集成,不用对腔体进行网格剖分,计算精度和效率都较高,使用方便,通用性好,具有较高的工程应用价值。使用该软件计算了圆形直腔、二面角和S形进气道的RCS,结果与其他方法吻合良好,具有比较好的计算精度。     

真三维立体显示系统中的体视观察算法分析与实现

在简要介绍真三维立体显示系统的基础上,以直线运动模型为出发点,对其中的体视观察算法进行了数学分析,并对可视体素进行了定义。最后结合象空间的光线投影法,提出了一种有针对性的体视观察算法实现思路。     

固体火箭发动机内部缺陷高分辨率检测

针对固体火箭发动机的特点，对工业CT成像结果数据处理方法进行了有效的改进，采用S－L滤波函数进行滤波修正，建立图像重建算法，对同种材料物体通过锐化边缘提高缺陷的空间分辨率；对密度差别较大的不同材料，采用不同的滤波函数分别处理，得到清晰的图像后再叠加成完整的图像，方法简单可行，实现了固体火箭发动机内部缺陷高清晰度的检测。     

机载天线罩的设计研究

研究了机载天线罩设计过程中的基本问题和综合设计方法,运用三维射线追踪法进行了计算机辅助设计,给出了布设防雷击部件的经验公式,介绍了工艺设计方法。电测结果较好地满足了设计要求。     

Dark Matter Particle Explorer and Its First Results

The Dark Matter Particle Explorer (DAMPE) is China's first astronomical satellite dedicated to the indirect detection of dark matter particles and the study of high-energy astrophysics. It can measure high-energy electrons and gamma-rays up to 10 TeV with unprecedentedly high energy resolution and low background. Cosmic ray nuclei up to 100 TeV can also be measured. DAMPE was launched on December 17, 2015, and has been operating smoothly in space for more than two years since then. The first results about the precise measurements of the electron plus positron spectrum between 25 GeV and 4.6 TeV have been reported.     

电离层拟合方法及路径参数量化分析

针对多层电离层,采用反抛物层作为连接层来描述电离层之间区域的电子密度分布.以电子密度和其相对于高度的一阶偏导数连续为依据,拟合出连接层的临界频率、半厚度和底高等电离层参数.将电离层的准抛物模型和连接层的反抛物模型中计算出来的等离子频率代入Appleton-Hartree公式和Snell定理,结合射线的几何结构完成多层电离层中的射线追踪,同时计算群路径、相路径和传输距离这3种重要的路径参数.分析当给定频率时,路径参数与入射角之间的关系,群路径、相路径与传输距离之间的关系,频率对路径参数之间变化关系的影响;同时分析了给定入射角时,路径参数与射线工作频率之间关系和入射角对于路径参数之间变化关系的影响.     

World grid of cosmic ray vertical cut-off rigidity for the last decade

Cosmic ray cut-off rigidity tables and maps over the world concerning the epochs 2010, 2015 and the current one 2020 have been constructed. These maps display the effective cut-off rigidity in every five degrees in latitude and in longitude at the altitude of 20 km above the surface of the international reference ellipsoid. The values of the geomagnetic cut-off rigidity were calculated in every 5° in latitude and in every 15° in longitude applying the well-known method of particle trajectory calculations resulted from the theory of the particle motion in the Earth's magnetic field. The applied software employed the 12th Generation of the International Geomagnetic Reference Field (IGRF 12) and trajectories were calculated at 0.01 GV intervals in order to determine the vertical cut-off rigidity for each location. Beyond the use of the calculated cut-off rigidity values as a basic reference of charged particle access to different geographical locations during quiet and/or more intense geomagnetic periods, these results can be used for a long- term forecasting of the geomagnetic conditions variations.     

First measurements of periodicities and anisotropies of cosmic ray flux observed with a water-Cherenkov detector at the Marambio Antarctic base

A new water-Cherenkov radiation detector, located at the Argentine Marambio Antarctic Base (64.24S-56.62 W), has been monitoring the variability of galactic cosmic ray (GCR) flux since 2019. One of the main aims is to provide experimental data necessary to study interplanetary transport of GCRs during transient events at different space/time scales. In this paper we present the detector and analyze observations made during one full year. After the analysis and correction of the GCR flux variability due to the atmospheric conditions (pressure and temperature), a study of the periodicities is performed in order to analyze modulations due to heliospheric phenomena. We can observe two periods: (a) 1 day, associated with the Earth’s rotation combined with the spatial anisotropy of the GCR flux; and (b) $～$ 30 days due to solar impact of stable solar structures combined with the rotation of the Sun. From a superposed epoch analysis, and considering the geomagnetic effects, the mean diurnal amplitude is $～$ 0.08% and the maximum flux is observed in $～$ 15 h local time (LT) direction in the interplanetary space. In such a way, we determine the capability of Neurus to observe anisotropies and other interplanetary modulations on the GCR flux arriving at the Earth.