An incidental error has occurred in the acknowledgment included in the footnote on the front page of the article (page 241). The correct version is presented below. We sincerely apologize to the authors for this inconvenience. We would like to thank Prof. Miroslaw Kutylowski and anonymous reviewers for their helpful suggestions to improve this paper. We also thank Ph. D Xiangfa Guo for his many helpful discussions and contribution to this paper.