轧机压下螺纹副回松机理试验和铜螺母螺牙塑扁鼓包分析
Rapping experiment of rolling mill pressure SCREW-PAIRS and plastic bulge of nut teeth analysis
相反，他提出地球是一个扁球面&两极稍扁、中间略鼓的扁球面。
Instead , he suggested it was an oblate spheroid & a sphere that is squashed at its poles and swollen at the equator .
扁鼓