finite difference operator meaning in English

有限差分格式
有限差分算子

Author , secondly , starts from the approximate expandness of square root operator , perform mathematical calculations for finite difference operator in frequency - space domain , fourier finite difference operator in mixing domain ( frequency - space and frequency - wavenumber domain ) and general screen operator in mixing domain , compare and discuss their precision of their wavefield , adaptability for lateral velocity variations , computation efficiency and stability . thirdly , author , applies the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) in frequency - wavenumber domain , to the prestack and poststack forward modeling and depth migration
第二，从平方根算子的近似展开出发对频率?空间域的有限差分算子、混合域(频率?空间域；频率?波数域)的fourier有限差分算子、混合域的广义屏算子进行了推导并对其波场描述精度、对横向变速的适应性、计算效率和稳定性进行了比较与评述。