We acknowledge the financial support by National Fundamen-tal Research Program of China (Grant No.2011CBA00200), the Natural Science Foundations of China (No.21203025), Fund of Education Committee of Fujian Province (JK 2013010 and JA13064), Science and technology major projects of Fujian Province (2013HZ0003) and project of Fujian Development and Reform Commission (2013-577). Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at http://dx.doi.org/10.1016/j.electacta.2015 .09.082.