nearly-freeEconomist⁴¹³⁰³⁺² 例句 In this thesis, a new finite difference time domain FDTD method is developed to treat a two- dimensional photonic crystal consisting of nearly-free- electron metals. 本论文首先发展了一种基于等离子模型的有限差分计算方法，并应用于二维金属光子晶体，有效地计算了该类光子晶体的能带结构。 cnki