航天器中频段力学环境预示的混合线连接建模方法

针对航天器中频段的力学环境预示问题,提出了一种航天器结构混合线连接建模方法。首先应用波动理论推导了波数空间下的线连接动态刚度矩阵,然后通过构造线连接处的位移形函数,采用傅里叶变换技术建立混合线连接模型。提出了模态插值、三角波和Shannon小波三种形函数构造方法,并对三类形函数的优缺点进行了对比。典型结构的仿真结果表明,提出的混合线连接建模方法具有较好的预示精度,可应用于航天器结构的中频段的力学环境预示。     

一体化太阳敏感器热分析与验证方法

为保证太阳敏感器在进行光电一体化设计后的光学系统热稳定性,满足电子元器件的工作温度降额要求,采取光学模型与热模型相结合的热分析方法,得出了包括光学组件在内的整机温度分布数据.采用温度边界设定结合太阳光外热流的热平衡试验方法对产品实际温度分布情况进行验证,结果表明一体化太阳敏感器在壳体温度达到55℃,且受到1太阳常数太阳光照射时,仍满足设计要求,且测试数据和分析结果吻合.     

基于fMRI的逻辑运算脑功能效应连接

联合主成分分析(Principal component analysis,PCA)和Granger因果关系检验方法,研究顶下小叶皮层在逻辑计算认知任务中起到的可能效应因果连接.以双侧顶下小叶激活区域为参考区域,利用PCA提取主要成分作为参考种子信号,计算其与大脑其余每个体素之间的Granger因果关系,并映射到全脑,形成Granger因果效应连接图.结果表明,顶下小叶将在逻辑计算任务下神经活动传播到额中下回、运动前区、扣带回等区域,同时受到枕叶视觉区、丘脑、壳核等区域神经活动的影响,得到了符合生理机制的脑功能效应连接网络.     

风沙流中沙粒相浓度的高频测量

在大气边界层风洞内采用高速CMOS相机记录了定常来流条件下运动沙粒的图像.根据二进制图像标记像素的连通性,从数字图像中提取相机拍摄区域内沙粒的数量N,由此计算得到风沙流的瞬时含沙量q.获取图像的同时,使用恒温式热线风速仪MiniCTA配合55R49热膜探头测量观测域上方主流位置和跃移层顶部附近的风速变化.实验结果表明,即使在定常风速下,瞬时含沙量也是非稳定的,为了真实的记录瞬时含沙量的变化,测量频率至少需要在100Hz以上.定常风速下,高浓度风沙流含沙量的最大波动幅度可达到其时均值的50%以上;而当定常来流风速值在沙粒起动风速附近时,低浓度风沙流的含沙量具有明显的间歇性.     

空间薄膜阵面结构褶皱分析

薄膜褶皱是空间薄膜阵面形面误差主要因素,其制约阵面技术性能参数。首先,基于ABAQUS软件,建立薄膜褶皱数值仿真过程和方法;对正方形薄膜阵面进行了褶皱数值模拟分析,包括分析模型和参数分析,考虑了预应力值、膜边形式（膜边、索边、卡框边）、粘结缝及粘结缝模拟方法、剪应力值对阵面褶皱的影响,取得了阵面褶皱参数特征和规律。论文方法和结论对薄膜阵面结构设计研发具有参考价值。
     

嵌金属丝端燃装药方案绝热层设计方法

根据固体火箭发动机绝热防护模型,提出了一种嵌金属丝端燃装药绝热层设计方法。用该法对某特定发动机燃烧室绝热层的设计结果表明:与动机原绝热层烧蚀相比,用本方法设计的绝热层可在绝热防护达到安全要求的同时,最大化地降低发动机消极质量。     

改进的被动段弹道解算平根数算法

根据被动弹道的特点,提出了一种适合于被动段弹道快速计算的改进平根数方法.根据自由段和再入段力学特点,阐述了改进算法的基本思路,使用神经网络求取再入阻力对轨道根数的影响,推导了改进方法的计算公式,给出了方法的计算步骤.从仿真计算结果可知,提出的算法具有速度快、精度高等特点.     

风沙两相流动光学测量及图像处理技术研究进展

介绍了自风沙动力学诞生以来所使用的各类光学测量方法,阐述了各种方法的优缺点和适用范围,针对最新光学测量技术在近代风沙两相流研究中的重要作用,着重介绍了PIV、高速数字图像测量及其图像处理技术在风沙两相流中的应用,指出光学测量在时间和空间的解析能力上的持续增长将为沙粒微观力学解析和风沙流宏观统计规律获取提供充足的支持。     

Tool Materials Rapid Selection Based on Initial Wear

Based on a large amount of literature about tool wear research, 873 tool wear curves are taken as samples, and statistical analysis is carried out to select the most suitable tool from all the tool materials suggested by the tool manufacturers. Statistical relationships between the initial wear and uniform wear periods are obtained. The results show that there is qualitative relationship between wear rate during initial wear period (WRIWP) and wear rate in uniform wear period (WRUWP) to certain extent. On this basis, a tool material rapid selection method based on the initial wear is put forward, and suitable tool materials for machining titanium alloy are selected. The experimental results indicate that this method is effective and useful. The new tool materials rapid selection can be used to select suitable cutting tool materials quickly before carrying out systematic machinability tests with the most suitable tool materials. The technology can be applied to doing the initial selection of cutting tool materials in either the machinability research or the workshop production.     

Heat Absorbing and Releasing Experiments with Improved Phase-change Thermal Storage Canisters

This article, based on authors' long-term study, proposes an improved foamed-Ni-packed phase-change thermal storage canister, which takes advantage of the foamed-Ni characteristic of instinctive porous structure and excellent properties to ameliorate its void distribution and thermal conductivity. The improved canister and the unimproved one without foamed-Ni package, are put to heat absorbing and releasing tests to investigate the effects of heat absorbing temperature upon the phase-change materials (PCM) melting time under three temperature schemes by using platinum resistance thermometers (PT100) and data acquisition modules (ADAM-4000) to gather the data of varying temperature. Afterwards, the computerized tomography (CT) is employed to scan the void distribution in both canisters. Compared to the unimproved canister, the experimental results evidence the superiority of the improved one in higher uniformity in void and temperature distribution as well as faster thermal responses.