With air resistance taken into account, the approximateequation for yarn curve slope is given as (9);
本文研究离心纺纱时的纱线曲线，计入空气阻力，得出近似方程式（9）。
2
In the paper, the principle and approximateequation and typical experiment have been researched. The method is visible and simple.
文中论述了该方法的原理，推导出一近似公式，并得典型实验验证。
3
With the aid of the projective operator technique, an integro-differential equation for the porbability density and an approximateequation for the mean first-passage time (MFPT) have been derived.