This operation creates a tapering of the workpiece via the use of a rotating hammer, which produces stepped columns and shafts of declining diameter.
这次行动创造了一个楔的工件通过使用旋转锤，生产，加强栏目和竖井下降的直径。
2
A method of stepped-diameter design for pneumatic conveying pipelines, as well as relationship among pressure loss, ratio of material to air, and mass flow rate of materials etc.