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风云四号是地球静止三轴稳定平台气象卫星,装载其上的辐射成像仪受剧烈的外热流日周期和年周期变化的影响,扫描机构和主光学系统等关键部件的温度每天波动可达40℃以上.光学及支撑结构如何适应剧烈的环境温度变化,并保证良好的像质,是地球静止三轴稳定平台遥感仪器系统设计的国际性难题.多种特性材料的匹配性设计以及适当支撑结构形式的采用,是避免和减少因温度大幅波动引起的光机变形及成像质量下降的良好策略.在轨数据表明,辐射成像仪克服了昼夜温差大的不利影响,敏感恒星时的弥散斑几乎仅覆盖一个像素,而且正午和子夜结果差别不大. 相似文献
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The experimental tests of tensile for lead-free solder Sn-3.5Ag were performed for the general work temperatures range from
11 to 90 °C and strain rate range from 5×10−5 to 2×10−2 s−1, and its stress—strain curves were compared to those of solder Sn-37Pb. The parameters in Anand model for solder Sn-3.5Ag
were fitted based on experimental data and nonlinear fitting method, and its validity was checked by means of experimental
data. Furthermore, the Anand model was used in the FEM analysis to evaluate solder joint thermal cycle reliability. The results
show that solder Sn-3.5Ag has a better creep resistance than solder Sn-37Pb. The maximum stress is located at the upper right
corner of the outmost solder joint from the symmetric center, and thermal fatigue life is predicted to be 3.796×104 cycles under the calculated conditions.
Foundation item: Project(50376076) supported by the National Natural Science Foundation of China 相似文献
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某地球静止轨道卫星光学相机由于CCD 器件功耗较大,并要求处于较低的工作温度水平,经论证确定采用热电制冷器对CCD的温度进行主动控制。设计了热电制冷器性能地面试验装置,分别在大气和真空环境中选用国内外不同型号的热电制冷器进行对比试验研究。试验得到了安装方式对冷热端温差的影响、输入功耗与冷热端温差的对应关系、负载功率与冷热端温差的对应关系以及大气和真空环境对制冷器的性能影响等数据。试验结果表明,在CCD负载下,制冷器冷热端的温差最大可达到45.8℃,能够满足CCD的低温工作需求。 相似文献
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