An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and ...An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 60232090 and 10774102)the Science & Technology Project from Shenzhen Government of China (Grant Nos. 2008340 and 200717)
文摘An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.
文摘云顶压强可用于估计云高,对气象观测和云特性研究等具有重要的作用。基于高分五号卫星搭载的多角度偏振探测仪(DPC)在氧气A吸收带设置的763 nm和765 nm两个波段进行了云顶压强反演方法的研究。首先,通过辐射传输模拟和多项式拟合得到了大气压强的计算公式,并对拟合公式进行了误差分析和校正。然后,分析了气溶胶、大气廓线等因素对云顶压强反演结果的影响,并进一步利用晴空地表对反演方法进行了稳定性测试和原理性验证。测试结果表明氧气A带方法稳定性较好,可以适用于不同天气状况和观测角度;验证结果表明DPC反演压强与DEM估算压强有很好的一致性,地表压强的平均偏差约为47.6 h Pa。最后,将DPC反演的云顶压强与MODIS云顶压强产品(MYD06)进行了对比,结果表明两颗卫星的云顶压强观测结果具有较好的空间一致性。
