用波函数展开法求解界面圆孔的SH波散射问题

研究了ＳＨ波绕界面圆孔散射的波函数展开理论。由入射，反射和透射波组成的自由波场与孔 的散射场叠加成总波场．将定义于两个半平面的散射场按一定方式延拓到全平面，通过 Ｈａｎｋｅｌ—Ｆｏｕｒｉｅｒ型积分来满足界面与孔缘处的边界条件，得到了确定待定系数的封闭代数方程组．给 出了具体算例，计算了在孔缘处的动应力集中系数分布．

NONLINEAR WATER WAVE PROPAGATING OVER UNEVEN BOTTOMS

Various types of wave group solutions of the weakly nonlinear waves may exist over uneven bottoms. In this paper, the variation of the zeroes of the dispersive and nonlinear terms,and the wave group solution in the third-order evolution equations are described for the case of mild and locally fastvarying water depths.

Surface Tension Effect on Harmonics of Rayleigh-Taylor Instability

Using the method of the parameter expansion up to the third order, explicitly investigates surface tension effect on harmonics at weakly nonlinear stage in Rayleigh-Taylor instability （RTI） for arbitrary Atwood numbers and compares the results with those of classical RTI within the framework of the third-order weakly nonlinear theory. It is found that surface tension strongly reduces the linear growth rate of time, resulting in mild growth of the amplitude of the fundamental mode, and changes amplitudes of the second and third har- monics, as is expressed as a tension factor coupling in amplitudes of the harmonics. On the one hand, surface tension can either decrease or increase the space amplitude; on the other hand, surface tension can also change their phases for some conditions which are explicitly determined.

Cauchy prior distribution-based AVO elastic parameter estimation via weakly nonlinear waveform inversion

Cauchy priori distribution-based Bayesian AVO reflectivity inversion may lead to sparse estimates that are sensitive to large reflectivities. For the inversion, the computation of the covariance matrix and regularized terms requires prior estimation of model parameters, which makes the iterative inversion weakly nonlinear. At the same time, the relations among the model parameters are assumed linear. Furthermore, the reflectivities, the results of the inversion, or the elastic parameters with cumulative error recovered by integrating reflectivities are not well suited for detecting hydrocarbons and fuids. In contrast, in Bayesian linear AVO inversion, the elastic parameters can be directly extracted from prestack seismic data without linear assumptions for the model parameters. Considering the advantages of the abovementioned methods, the Bayesian AVO reflectivity inversion process is modified and Cauchy distribution is explored as a prior probability distribution and the time-variant covariance is also considered. Finally, we propose a new method for the weakly nonlinear AVO waveform inversion. Furthermore, the linear assumptions are abandoned and elastic parameters, such as P-wave velocity, S-wave velocity, and density, can be directly recovered from seismic data especially for interfaces with large reflectivities. Numerical analysis demonstrates that all the elastic parameters can be estimated from prestack seismic data even when the signal-to-noise ratio of the seismic data is low.

Spectrophotometric determination of heparin with safranine T and their interaction mechanism

In weak acidic medium the alkaline cationic Safranine T interacts with acidic biological rnacromolecule heparin intensively causing the change of the molecular conformation, the maximum absorption wavelength and the absorption value. The optimum experimental condition was given and a new method to determine the heparin was established. The linear range was 0.05-2.0 mg/L and the correlation coefficient was 0.9974. The method has been applied to analyze the samples and the results are satisfactory. Furthermore, the interaction mechanism was indicated.

Asymptotic Behavior of Global Classical Solutions of Quasilinear Non-strictly Hyperbolic Systems with Weakly Linear Degeneracy

In this paper, we study the asymptotic behavior of global classical solutions of the Cauchy problem for general quasilinear hyperbolic systems with constant multiple and weakly linearly degenerate characteristic fields. Based on the existence of global classical solution proved by Zhou Yi et al., we show that, when t tends to infinity, the solution approaches a combination of C^1 travelling wave solutions, provided that the total variation and the L^1 norm of initial data are sufficiently small.