expansion method的用法和樣例：
例句
- The methods employed in studying the wave motion in phononic crystals are based on the plane-wave expansion method and supercell technique.
本研究以平面波展開法分析二維聲子晶體其徹體波與表面聲波的波傳行為及頻溝現象，並針對不同效應在調變聲波頻溝上作進一步的探討。 - Here the plane wave expansion method is adopted for calculating the band structure at each iteration.Then the photonic crystal can be optimized after iterations.
在迭代的過程中，我們採用平面波展開法計算光子晶體之能帶，經多次迭代計算后即可合成最佳化之光子晶體。
