The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid interv...The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid intervals. In this study, the cosine-modulated binomial window function （CMBWF）-based staggered-grid finite-difference method is proposed. Two new parameters, the modulated time and modulated range are used in the new window function and by adjusting these two parameters we obtain different characteristics of the main and side lobes of the amplitude response. Numerical dispersion analysis and elastic wavefield forward modeling suggests that the CMBWF method is more precise and less computationally costly than the conventional Taylor series expansion staggered-grid finite-difference method.展开更多
We prove some 3-adic congruences for binomial sums,which were conjectured by Zhi-Wei Sun.For example,for any integer m≡1（mod 3）and any positive integer n,we have v3（1/n ∑n-1X k=0 1/mk 2k/ k〉））≥min{3（n）,3（...We prove some 3-adic congruences for binomial sums,which were conjectured by Zhi-Wei Sun.For example,for any integer m≡1（mod 3）and any positive integer n,we have v3（1/n ∑n-1X k=0 1/mk 2k/ k〉））≥min{3（n）,3（m-1）-1},where 3（n）denotes the 3-adic order of n.In our proofs,we use several auxiliary combinatorial identities and a series converging to 0 over the 3-adic field.展开更多
基金supported by the National Major Research Equipment Development Projects(No.ZDYZ2012-1-02-04)the National Natural Science Foundation of China(No.41474106)
文摘The numerical dispersion and computational cost are high for conventional Taylor series expansion staggered-grid finite-difference forward modeling owing to the high frequency of the wavelets and the large grid intervals. In this study, the cosine-modulated binomial window function （CMBWF）-based staggered-grid finite-difference method is proposed. Two new parameters, the modulated time and modulated range are used in the new window function and by adjusting these two parameters we obtain different characteristics of the main and side lobes of the amplitude response. Numerical dispersion analysis and elastic wavefield forward modeling suggests that the CMBWF method is more precise and less computationally costly than the conventional Taylor series expansion staggered-grid finite-difference method.
基金supported by National Natural Science Foundation of China (Grant Nos. 11271185,11171140 and 11226277)the Initial Founding of Scientific Research for the Introduction of Talents of Nanjing Institute of Technology,China (Grant No. YKJ201115)
文摘We prove some 3-adic congruences for binomial sums,which were conjectured by Zhi-Wei Sun.For example,for any integer m≡1（mod 3）and any positive integer n,we have v3（1/n ∑n-1X k=0 1/mk 2k/ k〉））≥min{3（n）,3（m-1）-1},where 3（n）denotes the 3-adic order of n.In our proofs,we use several auxiliary combinatorial identities and a series converging to 0 over the 3-adic field.
