A local phase compress scheme is applied to suppress spiral and spatiotemporal chaos in the Fitzhugh-Nagumo and Panfilov systems. In the numerical investigation, the compress signal is limited to a small area in order to control the global spiral and spatiotcmporal chaos with or without noise. The simulation shows that the system becomes homogeneous stable within a few of 50 time units. A practical control of defibrillation and pattern formation is discussed.

SH wave field excited by circumferential shear source in cylindrically double layered media is theoretically analysed.Dispersion equation of cylindrical Love waves (guide waves) has been derived.Both existence condition and existence range of cylindrical Love waves are discussed.Dispersion and excitation of cylindrical Love waves are investigated by numerical calculation.It is discovered that the lowest order cylindrical Love waves have cut off frequency,which differs from Love waves in half space with horizontally double layered elastic media.The asymptotic expression of dispersion equation of cylindrical Love waves as well radius r₁→∞ consistently tends to the dispersion equation in the horizontal half space case,and cut off frequency tends to zero.The transient full waveform calculation is also calculated and illustrated, showing that realizing direct shear wave logs through exciting SH wave would be a more forthright way.

It emphasizes on the research of effects of thin layer and fissure on the full waveform is acoustic well logging by using the numerical simulation in the improved pressure-velocity finite difference (PV-FD) method. Array acoustic wave train records are numerically simulated for many sorts of asymmetrical horizontal layers around boreholes. And the variable density pattern of the really measured acoustic waveforms recorded by moving well logging tool is also simulatingly calculated and drawn. Being amplified (through the limitation to Stoneley wave's amplitude), the propagation of different types of waves through interface or layer is finely described.

Investigation for improving the method to solve leaky modes in acoustic oil well logging is introduced, and a numerical example of its applications is given.

Using a difference method of irregular meshes, a numerical model for 2-dimensional oil-water reservoir simulations is presented and its numerical results of two examples have been given when IMPES method is adopted. The numerical results of example 1 are in good agreement with the analytic solution. The number of difference meshes used for example 1 is less than that used in Petrosa's model of hybrid grid for the same example and the method given in this paper is more efficient and convenient. It is difficult to solve the problem of example 2 for the difference mehtod of rectangular meshes. However, satisfying results are also obtained when the method given here is used for the numerical solution of the example 2. The results show that this method of irregular difference meshes can be applied flexibly to probems of reservoir simulations with a complex boundary and a complex structure of stratum.