中文摘要：

目前现有的使图的谱半径增大的边变换方法中，边的移动方向几乎是不确定的。通过比较图的特征多项式，得到了几种使图的谱半径增大的边定向移动的新方法。这些方法不能从已有的结论推出，并且应用它们可以研究给定直径或边独立数的某些图的谱半径问题。

英文摘要：

Among all methods of edge transformation which make the spectral radius of graphs increase, the moving direc- tions of edges are almost non-determinate. By comparing the characteristic polynomials of two graphs, some new methods making the spectral radius of graphs increase were obtained, in which the moving direction of edges is determinate. These methods can not be obtained from the former results and can be used to investigate some problems on fixed diameter or edge independence number.