Extended Conservation Laws of Some Nonlinear Partial Differential Equations

Self-adjoint theorem is introduced to match the corresponding functional of the given differential equations, and then N\"{o}ether's theorem is used todetermine the extended conservation laws of the original equations. Finally, as the application of the method, the conservation laws of Drinfel'd-Sokolov-Wilson equation and Benjamin-Bona-Mahony equation are constructed.