We present a 3D approach to numerical modeling of the borehole-surface electromagnetic （BSEM） method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using th...We present a 3D approach to numerical modeling of the borehole-surface electromagnetic （BSEM） method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using the 3D integral equation method. The modeling results are consistent with analytical solutions. 3D Born approximation inversion of BSEM data is also conducted for reservoir delineation. The inversion method is verified by a synthetic reservoir model.展开更多
This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based o...This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based on the guaranteed cost theory, and a sufficient condition for the existence is given in terms of linear matrix inequality （LMI）. Secondly, a continuous sliding mode controller is proposed to handle the nonlinear, time - varying behavior of the vehicles. Simulation results demonstrate that the system responds rapidly and has good robust stability. Therefore, it provides theoretical references for further study on control problems of supercavitating vehicles.展开更多
The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipo...The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipole oriented along the wire elements of the screen,the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements,the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source,while the transmitted field is arisen from image transmission-line source.The expressions of related surface waves are derived and can be compared with previous results.展开更多
文摘We present a 3D approach to numerical modeling of the borehole-surface electromagnetic （BSEM） method. The 3D electromagnetic response created by a vertical line current source in a layered medium is modeled using the 3D integral equation method. The modeling results are consistent with analytical solutions. 3D Born approximation inversion of BSEM data is also conducted for reservoir delineation. The inversion method is verified by a synthetic reservoir model.
基金Supported by the National Natural Science Foundation of China（ No. 10802026） and Research Fund for the Doctoral Program of Higher Education of China （ No. 200802130003 ）.
文摘This paper focuses on robust control problems for supercavitating vehicles in the vertical plane. Firstly, for the mathematical model with mismatched uncertainties, the robust sliding mode function is designed based on the guaranteed cost theory, and a sufficient condition for the existence is given in terms of linear matrix inequality （LMI）. Secondly, a continuous sliding mode controller is proposed to handle the nonlinear, time - varying behavior of the vehicles. Simulation results demonstrate that the system responds rapidly and has good robust stability. Therefore, it provides theoretical references for further study on control problems of supercavitating vehicles.
文摘The reflecting and transmitting effects of a planar unidirectionally conducting screen are analyzed based on the accurate closed-form expression for electric field of an arbitrarily oriented electric dipole.For a dipole oriented along the wire elements of the screen,the screen acts as a perfectly electrically conducting plane.For a dipole perpendicular to the wire elements,the fields reflected by the screen can be interpreted as the contribution of an image dipole and image transmission-line current source,while the transmitted field is arisen from image transmission-line source.The expressions of related surface waves are derived and can be compared with previous results.
