噪声对相干衍射成像重构物体图像的影响

为探究噪声对物体图像重构的影响，在模拟的衍射图中加入泊松噪声和高斯噪声。改变信噪比，分析了扩展叠层扫描迭代算法迭代50次的图像重构结果。发现信噪比低于6时无法重构物体图像，信噪比为18时，可以恢复透射率为50%的物体图像。信噪比为22时，可以恢复透射率为10%的物体图像。结果表明噪声对透射率低的物体图像影响更大。信噪比大于22时噪声对不同透射率物体图像的重构均不再有影响。此研究为相干衍射成像算法的实际应用提供了理论指导。

Stability of Anchorage System of Youshui Bridge on Zhangjihuai Railway

The safety and stability evaluation of main cable and buckle anchorage system is always a key technical problem that puzzles engineers and technicians. This paper takes anchorage system of Youshui bridge on Zhangjihuai Railway as a study case，builts an FLAC3D physical model based on a detailed analysis of engineering geological characteristics and design materials. We analyzed the stress，deformation and plastic zone distribution characteristics of the surrounding rocks，prestress anchorage cables and anchor solids under various working conditions before and after construction of main cable，calculated the safety coefficients of each component and critical parts，and finally evaluated their safety. The results show that the deformation of surrounding rocks，prestress anchorage cables and anchor solids is small in the construction process，all of them are in a safe and stable state，having the security of reserves.