| 1. | Oscillation of second order difference operator
一类二阶差分算子的振动性 |
| 2. | Approximate difference operator
近似差分算子 |
| 3. | Backward difference operator
后向差分算子 |
| 4. | Multiscale decomposition of divided difference operators and nonstationary subdivision schemes of b - spline series
样条级数的非均匀细分算法 |
| 5. | In explicit depth extrapolation method of frequency - space fields , wavefield depth extrapolation is completed with convolution of short explicit difference operators and the wavefield
摘要在频率空间域显式叠前深度偏移中，波场深度延拓是通过显式差分短算子与波场的空间褶积完成的。 |
| 6. | Based on the study of the method of creating short explicit difference operators , a method for creating short explicit operators is presented , which is based on discrete smooth interpolation with control of phase - shift operator
基于对显式差分短算子的设计方法的研究，提出了一种基于相移算子约束的离散光滑插值的构造一维显式短算子的方法。 |
| 7. | In the thesis , the fundamental formula of ffd method derives from the square root that is approximated by a continued fraction expansion in the one - way wave equation . optimizations of the parameters of the finite - difference operator improve the validity of the method
本论文用连分式近似单程波波动方程中的平方根导出ffd算法的基本公式，并对ffd算法中的有限差分算子进行了系数优化，进一步提高了计算的有效性。 |
| 8. | The content of the study as follow : 1 to choice the ship form , mainly ship ' s overall size ; draft , according to design of shanghai deep - water port and development of container ; 2 . to deside the date of width ; depth ; path ; tract and sinkage through simulator tests ; 3 . to replenish and modify some date for channel design to very large container vessels in " design code of general layout for sea port " 4 . to study ship ' s turning area ; ship ' s stop distance the new and special content of the study as follow : 1 . statistics of path at the channel given by difference operators with the affections certain wind . currents . seas and other influences shows the path really needed under certain condition
并可在各类航道和水域的通航安全评估及操船方法，航迹带宽度，航道宽度，航迹带分布，船舶各种航行状态时的下沉量研究中应用。本课题研究的内容： ( 1 )根据洋山深水港设计规划和集装箱船舶的发展趋势，通过研究、分析、比较，选择最合适的船型，尤其是船舶主尺度和船舶吃水。 ( 2 )在大量模拟研究情况下，得出进港航道所需的航道宽度和深度。 |
| 9. | A hybrid migration method , named " fourier finite - difference migration " , is a post - stack depth migration scheme . the downward extrapolation operator is split into three operators : one operator is a phase - shift operator for a chosen constant background velocity , another operator is the well - known first - order correction term , and the third operator is a finite - difference operator for the varying of the velocity function . phase - shift downward extrapolation and finite - difference downward extrapolation preserves the advantage of phase - shift method and finite - difference method
傅立叶有限差分(简称ffd )偏移算法是一种叠后深度偏移算法，其向下延拓算子是一种混合算子，包括三项：一项是处理常速的相移算子，一项是一阶相移修正算子，最后一项是类似45度方程的有限差分算子，用来处理剧烈横向变速。 |
| 10. | 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。 |
