Electron crystallography image processing and its applications in materials science

It is pointed out that the images obtained by high - resolution electron microscope., is not always reflect the crystal structure directly, and the resolution of the structure image taken under a certain defocus condition is limited by the resolution of the election microscope. The structure image with atomic resolution can be directly obtained only with the high - voltage high - resolution electron microscopes. The advantage of introducing diffraction analysis into high - resolution electron microscopy (HREM) is clarified, and an electron crystallographic image processing technique set up by combining the diffraction crystallography with HREM is introduced in die present paper. This technique makes realizable the ab initio crystal structure determination by HREM. It is shown that the resolution of the structure image obtained with a medium - voltage electron microscope can be enhanced. up to the atomic resolution. Examples of applying this technique to the study of crystal structures and defects are given.