旋进电子衍射的动力学校正及纳米晶的三维重构

项目名称： 旋进电子衍射的动力学校正及纳米晶的三维重构

项目编号： No.11274263

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 杨奇斌

作者单位： 湘潭大学

项目金额： 90万元

中文摘要： 旋进电子衍射（PED）是1994年由英国Bristol大学的Vincent和Midgley开创的，它的特点是入射电子束沿着与电子显微镜的光轴成一定夹角的圆锥面运动，可收集到晶体的所有衍射斑点，故在未知纳米晶体的结构测定方面意义很大，得到了国际国内晶体学工作者的普遍重视，但是电子动力衍射的问题始终没有解决。本课题组负责人早在十一年前就在Ultramicroscopy （V87(2001)pp177-186）上发表了旋进电子衍射的解析表达式。当我们在进行结构分析时，每改变一个进动角和旋转角，同时照两张照片，一张高分辨像，一张衍射图，然后对每一张高分辨像和衍射图进行动力衍射校正，去噪，传递函数校正和优化处理后，再将大量的分析结果统一合成到三维空间中去，经傅里叶变换以后就有可能重构出未知晶体结构。本项目将建立一套用旋进电子衍射测定晶体结构的新方法及先进软件。

中文关键词： HAADF；像模拟计算；三维重构；；

英文摘要： Procession electron diffraction (PED) was established by Vincent and Midgley in 1994. The characterization of PED is that the incident beam in PED is scanned at a constant angle around the optic axis of the electron microscope. therefore, PED is able to collect diffraction spots of whole reciprocal space and is very suitable to solve the structure of unknown crystals with nano-size. Although, PED has attracted much attention of the worldwide crystallographers, the problem about correction of dynamical diffraction for PED has still not been solved. The applicant of this project has already solved this problem in 2001 (Ultramicroscopy （V87(2001)pp177-186）) . Analytical dynamical expressions for PED have been derived in this paper.Performing structure analysis of a crystal, we take two pictures with one high resolution image and another diffraction pattern simultaneously for each precession angle and rotation angle, then correct dynamical diffraction effect according to the expressions, transfer function ,reduce noisce, optimize data and finally merge all the data into a unified 3 dimensional reciprocal space, the structure could be solved through reverse Fourier transformation. A complete set of method for solving structure by PED and an advanced software package would be established under the support of this pr

英文关键词： HAADF；image simulation；3-dimension reconstruction；；