Annealing behavior of hexagonal phase content in cubic GaN thin films grown on GaAs (001) by MOCVD

The annealing behavior of the hexagonal phase content in cubic GaN (c-GaN) thin Films grown on GaAs (001) by MOCVD is reported. C-GaN thin films are grown on GaAs (001) substrates by metalorganic chemical vapor deposition (MOCVD). High temperature annealing is employed to treat the as-grown c-GaN thin films. The characterization of the c-GaN films is investigated by photoluminescence (PL) and Raman scattering spectroscopy. The change conditions of the hexagonal phase content in the metastable c-GaN are reported. There is a boundary layer existing in the c-GaN/GaAs film. When being annealed at high temperature, the intensity of the T0_B and LO_B phonon modes from the boundary layer weakens while that of the E₂ phonon mode from the hexagonal phase increases. The content change of hexagonal phase has closer relationship with annealing temperature than with annealing time period.     

(2S, 3R, 4R)-4, 5-O-异亚丙基-2, 3-环亚硫酰-2, 3, 4, 5-四 羟基戊酸乙酯 中硫原子手性的研究

我们在合成鞘氨醇3时,成功地分离到一对环亚硫酸酯1由于硫原子手性形成的非对映异构体,通过氢核磁共振谱分析和分子力学计算,确定了它们手性硫原子的绝对构型。     

有机-无机杂化膜的研究进展

有机-无机杂化膜由于具备了无机膜和有机膜各自的特点,具有良好的分离特性和物化稳定性,因而成为当前膜技术领域新型膜材料研究的热点.本文主要介绍了近年来国内外有机-无机杂化膜的研究现状、杂化膜的制备方法、结构和应用.