中文摘要：

用MoO3与多孔γ-Al2O3载体以机械混合法制备了一系列MoO3/γ-Al2O3样品.用扫描电子显微镜、X射线衍射、X射线光电子能谱分析、综合热分析（TG/DTA）和正电子湮没谱学研究了MoO3加载于γ-Al2O3后固熔分散过程.分别测量了不同含量的MoO3/γ-Al2O3经不同温度与不同时间烘烤后,以及采用逐步加载方式所得样品的正电子寿命谱.实验结果揭示了MoO3的热扩散过程：表现为MoO3逐步向载体的外表面、二次孔以及微孔中扩散;采用逐次加载方式能使MoO3更有效地在γ-Al2O3载体中分散;碾磨对MoO3的热扩散过程有影响.

英文摘要：

A series of the MoO3/γ-Al2O3 samples is prepared by mechanically mixing MoO3 with γ-Al2O3 powder.The solid state dispersion of the MoO3 in to the porous γ-Al2O3 is studied by SEM,XRD,XPS,TG/DTA,and positron annihilation spectroscopy.The positron annihilation lifetime spectra of the MoO3/γ-Al2O3 are measured as a function of the mass ratio of MoO3,heating temperature,heating time and in a way that the MoO3 is loaded gradually,separately.The experimental results show the process of the thermal dispersion of the MoO3 into the γ-Al2O3 support.It is shown that the MoO3 disperses into the outer surface first,and then into the secondary pores and the micro pores.The gradual Loading can make MoO3 effectively dispersed into γ-Al2O3.Grinding can also affecte the thermal dispersion process.