2D的芳纶丝理论直径是多少

V柱=ЛH柱R柱^2V锥=(ЛH锥R锥^2)3V柱/V锥=3H柱R柱^2/(H锥R锥^2)第一题3*2h*(2d/2)*(2d/2)/[h*(d/2)*(d/2)]=24:1第二题直径比1:3既是半径比为1:33*h*r*r/(2h*3r*3r)=1:6