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激光噪声对声频段横向小位移测量精度的影响 被引量:3
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作者 王洪伸 张超霞 +3 位作者 李治 刘奎 杨荣国 郜江瑞 《量子光学学报》 北大核心 2021年第1期15-20,共6页
本文研究了由厄米高斯模TEM00作为信号光场、TEM10模作为本地光组成的小位移产生及平衡零拍探测系统,实验上开展了基于该系统的声频段(20 Hz~20 kHz)横向小位移的产生和测量,讨论了系统散粒噪声、指向性噪声和激光强度噪声对最小可测位... 本文研究了由厄米高斯模TEM00作为信号光场、TEM10模作为本地光组成的小位移产生及平衡零拍探测系统,实验上开展了基于该系统的声频段(20 Hz~20 kHz)横向小位移的产生和测量,讨论了系统散粒噪声、指向性噪声和激光强度噪声对最小可测位移量的影响。通过噪声测量实验结果,当信噪比为3 d B时给出了声频段不同频率处的最小可测位移量,其中1 kHz处为3×10^(-9)m,10 kHz处为1.2×10^(-10)m,15 kHz处为0.85×10^(-10)m。本文为小位移测量系统中抑制声频段激光噪声,减小系统指向性噪声的实验和理论研究奠定了一定的基础。 展开更多
关键词 横向小位移 声频 指向性噪声 强度噪声
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A Simplified Analysis Method for the Lateral Deformation of Braced Excavations
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作者 许海勇 刘玮 陈龙珠 《Journal of Shanghai Jiaotong university(Science)》 EI 2013年第2期224-228,共5页
Pile-anchor retaining structure is widely used in foundation pit engineering and side slope engineering in many countries. In contrast to strut, pile-anchor retaining structure has its typical features and advantages.... Pile-anchor retaining structure is widely used in foundation pit engineering and side slope engineering in many countries. In contrast to strut, pile-anchor retaining structure has its typical features and advantages. It does not occupy the internal space of the foundation pit, and the project cost is much lower. Accurate prediction of the lateral displacement of the retaining structure is very important in the design stage. A simplified analysis method and several calculation assumptions of the lateral deformation of pile-anchor retaining structures are set up according to the engineering features. The expression function of lateral displacement versus depth is solved by means of a fitted function and the quasi-elastic summation method. The parameters are obtained through the stiffness equation of the anchors and the principle of minimum potential energy. The analytical evaluation of the lateral deformation curve is then completed, whose applicability is proved through practical engineering. 展开更多
关键词 EXCAVATION pile-anchor retaining structure fitted function lateral deformation analytical evaluation
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