If we classify these users by project, then, from a project-by-project point of view, the defect database appears to be unique for each user and each project.
A refractive defect of a lens or other optical system that prevents light rays from converging at a single point resulting in a blurred or imperfect image.
散光有折射缺陷的透镜或其它光学系统，阻碍光线汇聚于一个焦点，形成一个模糊或不完全的图象。
3
This paper analyzes the cause of civil-situ floor defect from the construction point of view, and put forward control measures to prevent casting slab defects.