If indeed the friction coefficient is independent of surface area, then when I tilt them they should start to slide roughly at the same Angle.
若摩擦系数真的，与接触面积没有关系，那么两者下滑时的角度，应该基本相当。
2
This surface has extreme hardness (60 RC. ), excellent wear and corrosion resistance, and low coefficient of friction.
这表面有极高的硬度（60局。），耐磨性和耐腐蚀性，低摩擦系数。
3
The fluidized-bed electrochemical reactor is a new type of electrocbemical reactor cbaracterized by large active surface and high mass transter coefficient.