For the value considered, the functional Ib is unbounded from below on a46a6497cf409725027032c333" title="Click to view the MathML source">Sr(c). By using a minimax procedure, we prove that for any c>0, there are infinitely many critical points of Ib restricted on a46a6497cf409725027032c333" title="Click to view the MathML source">Sr(c) with the energy . Moreover, we regard b as a parameter and give a convergence property of as b→0+.