二次反射
http://www.sec.ntnu.edu.tw/Monthly/99(326-335)/335-PDF/01-97063-%E7%89%A9%E9%AB%94%E5%9C%A8%E4%BB%BB%E6%84%8F%E5%A4%BE%E8%A7%92%CE%B8%E7%9A%84%E5%85%A9%E5%B9%B3%E9%9D%A2%E9%8F%A1%E4%B9%8B%E9%96%93%E6%9C%83%E6%88%90%E5%B9%BE%E5%80%8B%E5%83%8F%EF%BC%9F(%E6%9C%88%E5%88%8A2a).pdf