大型平铺贮箱卫星的液体晃动模型与晃动力矩分析

针对高轨气象卫星的远地点发动机点火过程中贮箱内液体晃动与星体耦合动力学问题,根据流体力学及小幅液体晃动理论,建立可等效的液体晃动力学模型和姿态耦合动力学模型,分析了大型平铺贮箱内液体晃动产生的干扰力矩。研究表明：在远地点发动机点火阶段,液体晃动对卫星将产生较大干扰力矩。     

Project Icarus: Optimisation of nuclear fusion propulsion for interstellar missions

The Daedalus spacecraft design was a two-stage configuration carrying 50,000 tonnes of DHe³ propellant. Daedalus was powered by electron driven Inertial Confinement Fusion (ICF) to implode the pellets at a frequency of 250 Hz. The mission was to Barnard's star 5.9 light years away in a duration of around 50 years. This paper is related to the successor Project Icarus, a theoretical engineering design study that began on 30 September 2009 and is a joint initiative between the Tau Zero Foundation and The British Interplanetary Society. In the first part of this paper, we explore ‘flyby’ variations on the Daedalus propellant utilisation for two different mission targets: Barnard's star and Epsilon Eridani, 10.7 light years away. With a fixed propellant mass a number of staged configurations (1–4) are derived for an optimal configuration but then moving to an off-optimal configuration due to the requirement for a high final science payload mass. Some comments are then made on the ICF pellet configuration compared to the typical pellets fielded at the National Ignition Facility (NIF) and those proposed for the Vista and Longshot fusion based propulsion designs. This is a working progress report, which aims to study perturbations of the Daedalus baseline design as part of a trade study. This is a submission of the Project Icarus Study Group.     

微弱光信号检测技术研究

为减少光电二极管与信号放大电路噪声对微弱光信号检测系统灵敏度的影响,提高检测精度.给出了微弱光信号检测电路噪声模型,并分析了灵敏度与带宽的关系,藉此能得到最佳的灵敏度和带宽组合.经仿真和实验表明该模拟有效,由此搭建的实验平台能测量nW级光功率.     

Large-scale Bright Fronts in the Solar Corona: A?Review of?��EIT waves��

??EIT waves?? are large-scale coronal bright fronts (CBFs) that were first observed in 195 Å images obtained using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). Commonly called ??EIT waves??, CBFs typically appear as diffuse fronts that propagate pseudo-radially across the solar disk at velocities of 100?C700 km?s^?1 with front widths of 50?C100 Mm. As their speed is greater than the quiet coronal sound speed (c _s ??200 km?s^?1) and comparable to the local Alfvén speed (v _A ??1000 km?s^?1), they were initially interpreted as fast-mode magnetoacoustic waves ( $v_{f}=(c_{s}^{2} + v_{A}^{2})^{1/2}$ ). Their propagation is now known to be modified by regions where the magnetosonic sound speed varies, such as active regions and coronal holes, but there is also evidence for stationary CBFs at coronal hole boundaries. The latter has led to the suggestion that they may be a manifestation of a processes such as Joule heating or magnetic reconnection, rather than a wave-related phenomena. While the general morphological and kinematic properties of CBFs and their association with coronal mass ejections have now been well described, there are many questions regarding their excitation and propagation. In particular, the theoretical interpretation of these enigmatic events as magnetohydrodynamic waves or due to changes in magnetic topology remains the topic of much debate.     

基于光纤传感网络的可变体机翼应变场数值模拟及实验验证

在不同飞行姿态及飞行条件下,可变体机翼智能结构及驱动器根据外部条件及控制指令,可以实现翼体自适应动态变形,表现出良好的空气动力学性能.由于翼体结构应力场与温度场的分布和作用形式复杂多样,因此需要对结构进行多物理场耦合分析,并准确获取翼体结构应变分布的有效信息.为此,采用COMSOL Multiphysic多物理场数值分...     

Generalized approach to resolution analysis in BSAR

Bistatic synthetic aperture radars (BSARs) have been the focus of increasing research activity over the last decade. The generalized ambiguity function (GAF) of bistatic SAR is introduced here. First, the GAF for BSAR is represented in the delay-Doppler domain, and is then expanded to the spatial (coordinates) domain. From the GAF, comprehensive knowledge regarding the resolution of BSAR can be extracted, including the range and azimuth resolutions, as well as the area of a resolution cell of BSAR. These general results are also applied to the performance analysis of several particular BSAR geometries, including the space-surface-BSAR (SS-BSAR) system, to demonstrate the potential ability of this newly introduced system.     

职业教育概念再认识

什么是职业教育,这是现代职教中必须弄清楚的一个基本问题。在分析职业教育本质属性的前提下,文章对职业教育的概念做了进一步的探讨,提出了现代职业教育的科学定义、内涵、特点和基本组成要素。     

随机振动校准加速度计方法研究

介绍了随机振动校准加速度计系统的实现.使用随机信号传感器绝对校准方法,得到了较为理想的加速度计频响曲线.与传统的方法相比在保证校准精度的前提下,提高了效率.     

工科《大学物理》CAI课件制作

作者运用Authorware、3Dmax、Premiere等多媒体制作工具，把文字、图片、动画、音频、视频等信息有机地结合起来，制作完成了新颖、实用、交互性强、功能强大的工科《大学物理》CAI课件制作并投入使用，解决了教师难教、学生难学的问题，得到了学生的极大欢迎并取得了良好的教学效果。本文介绍了作者制作中的技术手段及运用的体会。     

视觉及其融合惯性的SLAM技术发展综述

当前视觉同时定位与建图（Simultaneous localization and mapping,SLAM）技术已经成为导航定位领域重要的导航方式之一。为提升视觉SLAM全天候多场景的综合性能,融合多种信息的视觉SLAM技术得到了快速发展。本文系统综述了近年国内外视觉SLAM的研究成果。首先归纳整理了视觉及视觉/惯性SLAM中的前端里程计、后端优化、回环检测和地图构建关键环节。在纯视觉SLAM技术分析方面,围绕传统基于几何变换和现代基于深度学习的两大类视觉SLAM方法开展讨论,并梳理了相关具有代表性的视觉SLAM技术。在详细阐述视觉/惯性组合导航的多信息融合SLAM方法基础上,分析了近年基于异源图像的视觉及其与惯性组合的SLAM导航技术进展。最后对视觉SLAM的未来发展方向进行了针对性展望。