飞机整体壁板智能数控编程系统

结合飞机整体壁板结构特点、典型加工工艺路线.针对目前数控编程中存在的问题,对智能数控编程相关技术作了一定的探索.主要内容包括飞机整体壁板智能数控编程系统结构建立、数控加工知识综合表示、广义槽加工单元分层识别、基于几何特性加工刀具自动选取、基于知识推理的加工自动排序等.最后应用上述技术开发了飞机整体壁板快速数控编程系统.     

太阳帆航天器被动姿态控制研究

针对由有效载荷、太阳帆和4个控制叶片所组成的太阳帆航天器系统,从物理模型出发,利用欧拉方程建立了姿态动力学模型,并通过数值仿真对太阳帆航天器基于控制叶片的对日定向性能进行了研究。研究结果表明,在行星际飞行中太阳帆航天器可以通过使控制叶片保持偏置来保持姿态稳定。     

整体加筋壁板中三维裂纹扩展过程模拟

基于有限元法和线弹性断裂力学理论,使用通用商业软件ABAQUS模拟了三维裂纹在飞机整体加筋板结构中的扩展过程,考察了一种典型的开裂模式,提出了一种对三维裂纹问题边界效应的修正方法,重点分析了裂纹在结构倒角附近区域的扩展规律。     

Nickel Isotopic Composition and Nickel/Iron Ratio in the Solar Wind: Results from SOHO/CELIAS/MTOF

Using the Mass Time-of-Flight Spectrometer (MTOF)—part of the Charge, Elements, Isotope Analysis System (CELIAS)—onboard the Solar Heliospheric Observatory (SOHO) spacecraft, we derive the nickel isotopic composition for the isotopes with mass 58, 60 and 62 in the solar wind. In addition we measure the elemental abundance ratio of nickel to iron. We use data accumulated during ten years of SOHO operation to get sufficiently high counting statistics and compare periods of different solar wind velocities. We compare our values with the meteoritic ratios, which are believed to be a reliable reference for the solar system and also for the solar outer convective zone, since neither element is volatile and no isotopic fractionation is expected in meteorites. Meteoritic isotopic abundances agree with the terrestrial values and can thus be considered to be a reliable reference for the solar isotopic composition. The measurements show that the solar wind elemental Ni/Fe-ratio and the isotopic composition of solar wind nickel are consistent with the meteoritic values. This supports the concept that low-FIP elements are fed without relative fractionation into the solar wind. Our result also confirms the absence of substantial isotopic fractionation processes for medium and heavy ions acting in the solar wind.     

Mission analysis and performance comparison for an Advanced Solar Photon Thruster

The so-called “compound solar sail”, also known as “Solar Photon Thruster” (SPT), is a design concept, for which the two basic functions of the solar sail, namely light collection and thrust direction, are uncoupled. In this paper, we introduce a novel SPT concept, termed the Advanced Solar Photon Thruster (ASPT), which does not suffer from the simplified assumptions that have been made for the analysis of compound solar sails in previous studies. After having presented the equations that describe the force on the ASPT and after having performed a detailed design analysis, the performance of the ASPT with respect to the conventional flat solar sail (FSS) is investigated for three interplanetary mission scenarios: an Earth–Venus rendezvous, where the solar sail has to spiral towards the Sun, an Earth–Mars rendezvous, where the solar sail has to spiral away from the Sun, and an Earth-NEA rendezvous (to near-Earth asteroid 1996FG3), where a large change in orbital eccentricity is required. The investigated solar sails have realistic near-term characteristic accelerations between 0.1 and 0.2 mm/s². Our results show that an SPT is not superior to the flat solar sail unless very idealistic assumptions are made.     

Comparative study of high-latitude,mid-latitude and low-latitude ionosphere on basis of local empirical models

The analysis of the regular features of the high-, mid- and low-latitude ionosphere characteristics has been carried out using local empirical models. The local empirical models were derived from the manual scaled ionogram data recorded by DPS-4 Digisondes located at Norilsk (69 N, 88E), Irkutsk (52 N, 104E) and Hainan (19 N, 109E) for a 6-year period from December, 2002 to December, 2008. The technique used to build the local empirical model is described. Primary focuses are diurnal, seasonal and solar cycle variations of the peak electron density and the peak height under low solar activity and their changes with increasing solar activity. The main objective of the paper is to reveal both common and specific features of high-, mid- and low-latitude ionosphere. Based on earlier comparisons with the International Reference Ionosphere model, we analyze how the common and specific features are reproduced by this model.     

基于Matlab的FY-4星载扫描辐射计午夜太阳入侵模拟

用Matlab软件建立了动态仿真模型,以分析太阳午夜入侵对风云四号(FY-4)地球静止气象卫星扫描辐射计的影响。给出了仿真算法的流程,介绍算法中太阳光线方向、受照面转换和主镜反射特性计算等难点,并说明为提高效率采用的近似简化和优化处理。计算结果与文献中GOES卫星的实测数据相近,表明该仿真模型可较准确地模拟午夜太阳入侵,所获数据准确。     

太阳帆航天器姿态控制技术综述

太阳帆作为一种无工质消耗的新型航天器推进技术,逐渐受到国内外航天界的广泛关注。文章首先综述了太阳帆航天器控制技术的发展现状,重点分析了太阳帆航天器姿态控制技术的特点和难点;其次,按照执行机构的不同,分别介绍了近年来国内外航天领域提出的多种太阳帆航天器姿态控制方案,针对各个方案的优缺点加以分析;最后,对该领域未来的发展前景进行了展望。     

表面带电对航天员出舱活动的影响及对策分析

根据我国某载人航天器在轨飞行时的空间环境和航天器表面带电的机理,对航天器表面带电进行了仿真,并对结构切割地磁场的感应电势进行计算。在此基础上,分析了表面带电对航天员出舱的影响,以及出舱安全性防护措施,计算出主动电位控制系统最大发射电流。研究结果可为航天员出舱安全防护提供参考。