扫描相干衍射成像（PCDI）是近年来快速发展的一种新型无透镜成像技术，具有高分辨、高稳定性、多功能的成像能力。众所周知，相对于样品的二维高分辨结构信息，纳米尺度的三维结构信息对于材料和生命科学来说具有更为重要的意义。所以PCDI在二维成像上获得巨大成功后，很快就被拓展至三维成像。本项目将全力发展基于STXM的极限分辨三维PCDI技术和数据分析方法，大力提升上海光源的三维空间分辨能力。重点发展基于直接耦合PXCT（扫描相干衍射X射线CT）和多切片方法的新型低剂量高分辨三维成像方法学，以满足生命、材料、环境等前沿科学对原位三维极限分辨技术的迫切需求。同时还将结合其他PCDI技术（如超分辨、飞扫等），探索和发展更加新异的低剂量三维PCDI技术，以实现更为高效便捷的三维纳米尺度成像。本项目所发展的新型三维成像方法将进一步拓宽同步光源的科研潜力和应用领域，使光源更好的服务于国内外用户的高水平研究。

The ptychographic coherent diffractive imaging (PCDI) is a novel lensless imaging technology under rapid development in recent years, which has the imaging capability of high resolution, high stability and multiple functions. As is well known, compared to the two-dimensional (2D) high-resolution structural information of a specimen, the nanoscale three-dimensional (3D) structural information is more significant to material science and biology. Therefore, PCDI was soon generalized to 3D imaging after its great success in 2D imaging. In this project, we will make great efforts to develop the ultimate-resolution 3D PCDI technology and data analysis methods based on STXM, and try hard to elevate the 3D spatial resolving power of Shanghai light source. The emphasis is put on the development of new low-dose high-resolution 3D imaging methods based on the direct coupled ptychographic tomography and the multi-slice approach, to satisfy the active demand for the in-situ 3D ultimate resolution techniques in the leading edge sciences such as material, life, environment, etc. In the meantime, by combination with other ptychography technologies (such as superresolution, fly-scan, etc), we will explore and develop more novel low-dose 3D PCDI techniques to implement nanoscale 3D imaging with higher efficiency and better conveniece. The new 3D imaging methods developed in this project will broaden the research potential and application field of our synchrotron light source, and enable the light source to provide better services for high-level scientific research of users from all over the world.