By means of the multiple-scale expansion method, the coupled nonlinear SchrSdinger equations without an explicit exteal potential are obtained in two-dimensiona
The Lie group theoretical method is used to study the equations describing materials with competing quadratic and cubic nonlinearities. The equations share some
This paper presents a new method for extract three-dimensional (3D) discrete spherical Fourier descriptors based on surface curvature voxeis for pollen particle