White Emitting ZnS Nanocrystals： Synthesis and Spectrum Characterization

Spherical organic-bonded ZnS nanocrystals with 4.0 4-0.2 nm in diameter are synthesized by a liquid-solid-solution method. The photoluminescence spectrum of sample （[S^2-]/[Zn^2＋] = 1.0） shows a strong white emission with a peak at 490nm and - 170 nm full widths at half maximum. By Gauss fitting, the white emission is attributed to the overlap of a blue emission and a green-yellow emission, originating from electronic transitions from internal S^2- vacancies level to valence band and to the internal Zn^2＋ vacancy level, respectively. After sealingZnS nanocrystals onto InGaN chips, the device shows CIE coordinates of （0.29,0.30）, which indicates their potential applications for white light emitting diodes.     

在不同语境下对几个物理学名词的阐释

经典物理学中的基本概念都是由西方建立,众多物理学名词最早也是用欧美所用语言来定名.我国学习和吸收西方科学技术知识,主要途径是翻译外文书籍.这一现实,就导致同一个物理概念,不同的语言可能呈现给学习者不同的物理图像,造成对物理学理解上的差异.本文选取高中物理教材中几个容易混淆的或乍一看难以理解的名词,在中英两种语境下,对其逐一阐释.