摘要
Submission of a manuscript implies: that the work described has not been published before (except in the form of an abstract or as part of a pub- lished lecture, review, or thesis); that it is not under consideration for publication elsewhere; that its publication has been approved by all co-authors, if any, as well as tacitly or explicitly by the responsi- ble authorities at the institution where the work was carried out. The au- thor warrants that his/her contribution is original and that he/she has full power to make this grant. The author signs for and accepts responsibility for releasing this material on behalf of any and all co-authors. Transfer of copyright to Science China Press and Springer becomes effective if and when the article is accepted for publication. After submission of the Copy- right Transfer Statement signed by the corresponding author, changes of authorship or in the order of the authors listed will not be accepted by Science China Press and Springer. The copyright covers the exclusive right (for U.S. govemment employees: to the extent transferable) to re- produce and distribute the article, including reprints, translations, photo- graphic reproductions, microform, electronic form (offiine, online) or other reproductions of similar nature.