Wear mechanism map of uncoated HSS tools during drilling die-cast magnesium alloy

A wear mechanism map of uncoated high-speed steel (HSS) tools was constructed under the conditions of dry-drilling die-cast magnesium alloys. Three wear mechanisms appear in the map based on the microanalysis of drilled HSS tools by SEM, including adhesive wear, abrasive wear and diffusion wear. In the map, there exists a minor wear region which is called "safety zone". This wear mechanism map will be a good reference for choosing suitable drilling parameters when drilling die-cast magnesium alloys.

基于Arc Hydro Tools的流域特征自动提取——以贵州省内乌江流域为例

简要回顾和讨论了基于栅格数字高程模型(DEM)自动提取流域特征的原理和方法，介绍了一个新的基于ArcGIS开发的提取流域特征的工具Arc Hydro Tools，基于Arc Hydro Tools 提取流域特征包括5 个流程：DEM 的预处理、水流流向的确定、汇流栅格图的生成、河网的自动生成、子流域边界的划分。最后以贵州省内乌江流域为研究区进行了试验，试验结果表明：提取结果的精度在总体上是符合要求的，但在地势平坦区或人类活动干扰较大的地区，提取的结果与实际相差较大。从提取的效率和试验结果的精度两方面来看，基于Arc Hydro Tools 的流域特征自动提取是切实可行的。