back propagation的用法和樣例：
例句
- The free transverse vibration in an axially moving beam on fixed support is investigated by wave propagation.
摘要用波傳播法分析研究了兩端固支軸向運動梁的橫向自由振動。 - The simulation using the bi-directional beam propagation method proves that the demultiplexer can have very low insertion loss and high isolation ratio.
藉由雙向光束傳播法來模擬此元件，結果顯示此解多工器具有很低的插入損耗和高的隔離度。
