Abundances of Light Elements

This paper briefly reviews a few relevant features about the abundances of light elements (D, ⁴He, ⁶Li, ⁷Li, ⁹Be) in the Milky Way. It places special emphasis on metal-poor stars. Observational concerns are discussed. The use of ⁷Li and ⁶Li as cosmological probes and of ⁹Be as a chronometer for the early evolution of our Galaxy are discussed.     

在线加工用高精度二维微小角度传感器的设计

提出了一种基于内反射效应的二维微小角度传感器的设计方法。该传感器采用光学差动法,通过检测光强实现了对二维方向上微小角度的测量。研制的角度传感器俯仰角和偏转角的测量范围为±500arcsec;具有优于0.1arcsec的分辨力。     

Process of establishing design requirements and selecting alternative configurations for conceptual design of a VLA

In this study, a process for establishing design requirements and selecting alternative con-figurations for the conceptual phase of aircraft design has been proposed. The proposed process uses system-engineering-based requirement-analysis techniques such as objective tree, analytic hier-archy process, and quality function deployment to establish logical and quantitative standards. Moreover, in order to perform a logical selection of alternative aircraft configurations, it uses advanced decision-making methods such as morphological matrix and technique for order prefer-ence by similarity to the ideal solution. In addition, a preliminary sizing tool has been developed to check the feasibility of the established performance requirements and to evaluate the flight perfor-mance of the selected configurations. The present process has been applied for a two-seater very light aircraft (VLA), resulting in a set of tentative design requirements and two families of VLA configurations: a high-wing configuration and a low-wing configuration. The resulting set of design requirements consists of three categories: customer requirements, certification requirements, and performance requirements. The performance requirements include two mission requirements for the flight range and the endurance by reflecting the customer requirements. The flight performances of the two configuration families were evaluated using the sizing tool developed and the low-wing configuration with conventional tails was selected as the best baseline configuration for the VLA.     

基于局部大气偏振特性的仿生导航方法

目前主流的偏振导航算法中，思路通常为通过对全天域偏振图像的获取拟合出太阳子午线或中性点的位置，进而判断导航方向。现提出一种新的导航方向获取算法，可在小视场条件下，通过对太阳方向矢量的拟合判断导航方向。在此基础上进行了计算机仿真和室外实验，利用偏振相机获取了天顶区域大气偏振分布模式；利用斯托克斯矢量分析法解算出了大气偏振模式的分布情况，包括其中偏振度和偏振角的信息，初步证实了解算算法在实际情况下的可行性和精度，导航精度可达到0.2°左右。     

偏振光导航

本文简单的介绍了偏振光导航的发展背景、偏振光导航的基本原理以及偏振光导航的发展历程,同时提出了偏振光导航需要解决的问题。     

用于航天电子设备的PMI泡沫夹层结构力学性能试验验证

针对应用于空间站的我国首个航天综合一体化电子系统设备的减重需求,通过试验验证了碳纤维/PMI/碳纤维、铝合金/PMI/铝合金2种PMI泡沫夹层结构的物理及力学性能,并与航天电子设备中常用的铝合金、碳纤维结构进行对比分析。研究表明,相比于铝合金结构,PMI泡沫夹层结构具有显著的减重效果以及良好的阻尼和比刚度特性,平均减重比约为40%,力学响应量级降低了40%～50%,为空间站电子设备的轻量化设计奠定了基础。     

空间目标在天基光学探测中的特性分析与仿真

分析了空间目标的分布及几何特性,研究了空间目标光学特性与天基探测系统、太阳以及目标自身参数的关系,提出了空间目标光学特性仿真的思路,建立的天基空间目标光学特性分析系统可以计算并绘制相对距离、太阳相位角及目标星等变化曲线.由于很难获取准确的空间目标实际光度数据,文中提出了对仿真结果的验证方法.通过对仿真结果的分析,得出了天基空间目标光学探测的特点,为天基光学探测和识别的研究提供了参考.     

Three-line structured light vision system for non-cooperative satellites in proximity operations

Adapter ring is a commonly used component in non-cooperative satellites,which has high strength and is suitable to be recognized and grasped by the space manipulator.During proximity operations,this circle feature may be occluded by the robot arm or limited field of view.Moreover,the captured images may be underexposed when there is not enough illumination.To address these problems,this paper presents a structured light vision system with three line lasers and a monocular camera.The lasers proje...     

可被蓝光激发的白光LED用红色荧光粉材料体系与发光性能研究

综述并讨论了目前研究的可被蓝光LED芯片有效激发且具有宽发射带的红色荧光粉,可以得出：白光LED用红色荧光粉主要包括碱土金属硫化物、新型氮化物及硅酸盐等,这些红色荧光粉均可被460 nm蓝光激发,并具有宽发射光谱的特点。同时着重分析了其晶体结构与荧光性能之间的联系,并探讨了高显色指数和色温可调的白光LED用红色荧光粉下一步的研究方向与应用趋势。     

考虑恒滞差流动的爆震波特性参数计算

在两相脉冲爆震的研究过程中,以恒滞差流动假设为基础,考虑气液两相性来计算爆震波的特性参数。计算结果与实验数据对比表明:考虑气液两相性计算得到的爆震波特性参数更能真实反映两相脉冲爆震的流动情况。