正弦波模型化测量方法及应用

本文对应用较多的几种正弦波模型化测量方法进行了综述，它们是曲线拟合法、直方图统计分析法、FFT法和拍频法。较详细地介绍了这几种测量方法的典型用途以及特点，通过比较几种方法的优缺点，讨论了它们应用中的局限性。     

Integration of lessons from recent research for “Earth to Mars” life support systems

Development of reliable and robust strategies for long-term life support for planetary exploration must be built from real-time experimentation to verify and improve system components. Also critical is incorporating a range of viable options to handle potential short-term life system imbalances. This paper revisits some of the conceptual framework for a Mars base prototype which has been developed by the authors along with others previously advanced (“Mars on Earth^®”) in the light of three years of experimentation in the Laboratory Biosphere, further investigation of system alternatives and the advent of other innovative engineering and agri-ecosystem approaches. Several experiments with candidate space agriculture crops have demonstrated the higher productivity possible with elevated light levels and improved environmental controls. For example, crops of sweet potatoes exceeded original Mars base prototype projections by an average of 46% (53% for best crop) ultradwarf (Apogee) wheat by 9% (23% for best crop), pinto bean by 13% (31% for best crop). These production levels, although they may be increased with further optimization of lighting regimes, environmental parameters, crop density etc. offer evidence that a soil-based system can be as productive as the hydroponic systems which have dominated space life support scenarios and research. But soil also offers distinct advantages: the capability to be created on the Moon or Mars using in situ space resources, reduces long-term reliance on consumables and imported resources, and more readily recycling and incorporating crew and crop waste products. In addition, a living soil contains a complex microbial ecosystem which helps prevent the buildup of trace gases or compounds, and thus assist with air and water purification. The atmospheric dynamics of these crops were studied in the Laboratory Biosphere adding to the database necessary for managing the mixed stands of crops essential for supplying a nutritionally adequate diet in space. This paper explores some of the challenges of small bioregenerative life support: air-sealing and facility architecture/design, balance of short-term variations of carbon dioxide and oxygen through staggered plantings, options for additional atmospheric buffers and sinks, lighting/energy efficiency engineering, crop and waste product recycling approaches, and human factor considerations in the design and operation of a Mars base. An “Earth to Mars” project, forging the ability to live sustainably in space (as on Earth) requires continued research and testing of these components and integrated subsystems; and developing a step-by-step learning process.     

夫兰克-赫兹实验中影响曲线形状的因素分析

夫兰克-赫兹实验是近代物理学重要的实验之一,对物理学有深远的影响。主要分析实验中影响曲线形状的三个重要因素,得出了这些因素变化时的实验曲线变化规律,深入分析曲线变化的原因,从而确定了氩原子夫兰克-赫兹实验的最佳工作参量。     

双喷管差动式小推力测量装置的设计与分析

为了研究喷管型面对小推力火箭发动机推力性能的影响,设计并建设了双喷管差动式小推力测量装置及其附属设备.在测量装置中,基准喷管和待测喷管同轴反向设置,通过测量结构应变来直接测量两个喷管的推力差.对测量装置进行了简化模型理论分析,导出其灵敏系数理论公式.依据该公式进行关键参数设计,确定合理的灵敏系数,指导试验系统设计,以保证测量精度.验证性试验表明测量装置可以测量牛级推力差,标定曲线线性较好,以基准喷管推力作为比较对象,推力差的相对扩展不确定度为0.5％.推力差与基准喷管推力的比值越小,以基准喷管推力为比较对象的相对测量不确定度越小.测量装置可以用于小推力火箭发动机喷管性能分析及优化的试验研究.     

基于最小二乘支持向量机的SAR平台定位

将SAR平台定位分解为粗略定位和精确定位两个阶段。首先,在SAR正侧视成像的条件 下,利用某个方位门内的所有控制点,采用非线性最小二乘平差粗略估计出SAR平台在该方 位时刻的空间位置,并从理论上推导了控制点的误差协方差矩阵到SAR平台定位的误差协方 差矩阵的传递规律。其次,利用各个方位时刻粗略估计的SAR平台位置,采用最小二乘支持 向量回归机精确估计SAR平台的运动方程,从而精确估计SAR平台在某个时刻的空间位置。仿 真试验表明,本文提出的方法能够精确地反演出SAR平台的空间位置。
     

非对称来流下带隔板的二维短隔离段研究

在隔离段中放置隔板，可以在满足气动性能的前提下缩短隔离段的长度。采用数值计算的方法对带隔板的二维隔离段与不带隔板的隔离段性能进行了比较，对非对称来流条件下不同进口附面层厚度隔离段内弯曲隔板的形状进行了研究，给出了非对称来流条件下隔离段内弯曲隔板的设计参数。结果表明，在进口马赫数为2，隔离段进口下板附面层厚度δ／H=0．24，上板附面层厚度为0时，通过放置弯曲隔板，在进出口压比相同与出口总压恢复系数基本不变的情况下，隔离段长高比减小了33％。     

一种水下使用的大型排水气囊

文章主要介绍了一种大体积高强度排水气囊的工作程序、组成、地面试验的情况及其已达到的技术指标。     

空间相机温度解算方法的分析与研究

通过温度解算完成相机主体温度测量,是相机主体温控系统实现的关键环节之一.传统的温度解算方法存在数据存储量大、可移植性差、温度映射精度低等缺点.文章提出一种拟合温度解算法,针对不同的系统需求,给出两种改进方案,对拟合温度解算法及其改进方案的原理、性能及实现方式进行描述与分析.实践证明,该方法具有占用内存小、可移植性好、温...     

提高空间环模设备中铝热沉高真空气密性的工艺措施

我国大型空间环境模拟器的铝热沉,工作于-196～+100℃的温度,内压最高1.6MPa。其中主容器热沉是一个直径10.5m、高20m 的鼠笼形立式铝列管热交换器。整个热沉由2500多根铝管焊接而成,焊缝数量超过5000道。热沉有很严格的真空气密性要求,整个热沉的总漏率要求不大于1×10~(-6)Pa·m~3/s。文章分别从管件检测、纯铝焊接、高真空检漏等方面论述了确保热沉高真空气密性的措施。     

一种成像敏感器对月定姿算法

成像敏感器根据月像来确定卫星对月姿态角。分析了月球光学系统成像模型以及卫星两轴姿态角与月像边缘曲线方程的关系，利用分析结果并结合月像边缘点的曲线拟合提出了一种新的卫星对月定向姿态确定方法。此算法克服了非零姿态月像边缘的非圆现象并且在部分月像下也可完成姿态确定，仿真工作显示了新算法的有效性。