The direct process for ( n, p) or ( p, n) reaction is treated as a knock-out reaction and calculated by conventional DWBA ( distorted wave Born approximation) theory in the zero-range approximation. 将(n,p)或(p,n)反应的直接过程看成是一种敲出反应并用通常的在零程近似下的DWBA理论进行计算。