Open access
Submitted: June 21st, 2011 Published: December 22nd, 2011
DOI: 10.5772/38502
From the Edited Volume
Edited by Dongmei Chen
Submitted: June 21st, 2011 Published: December 22nd, 2011
© 2011 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.0 License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.