基于变量变换级数展开法，获得了掩埋矩形光波导及脊形光波导的矢量本征模及其传播常数。变量变换使无限平面映射成单位平面，从而使单位平面边界上的电磁场自然为零，消除了非物理反射，提高了计算精度；另外，由于这种方法所导致的矩阵阶数小，因此计算效率较高。分析的结果与已发表的结果吻合较好，可以为优化波导光电子器件的结构提供参考。

The usual mode sets for the dynamics modeling of flexible spacecraft are reviewed. Some mode reduction criterions for the selection of system retained modes are summarized. It is pointed out that the modal cost analysis and the internal balance theory are for the system mode selection and there is the problem how to use these criterions for the component elastic mode or the system elastic deformation mode selection. A tactic for using the order reduction criterions for the dynamics modeling is introduced. An example is given to show the comparison of modeling results with different mode sets and to illustrate how to use the mode reduction criterions for the dynamics modeling of flexible spacecraft.