backward difference短语¹¹⁴⁴⁶⁷⁺⁴ 基本例句 反向差分,后向差分 By using backward difference of space- time intensity correlation function with respect to time delay, the two-dimensional velocity vector of a moving diffuser can be measured. 利用远场时变散斑空-时强度相关函致的有限差商可以测量散射体运动的二维速度矢量。 cnki