中文摘要：

钙钛矿结构的复杂氧化物因其丰富的物理性能而成为研究热点。本文选取了SrTiO3、BiFeO3、NdGaO3三种钙钛矿结构的氧化物材料，运用透射电镜、JEMS软件模拟等方法研究其晶体结构转换关系。通过对正交、菱方畸变的钙钛矿结构进行立方定向转换的具体方法做理论推导，得到了三种定向之间的转换矩阵，并结合电子衍射、模拟、高分辨像验证了推导结果。我们的研究为畸变钙钛矿结构材料统一为等效立方晶胞讨论提供了依据。

英文摘要：

Complex oxides with perovskite structure have been a research hotspot for their abundant physical properties. Based on the three kinds of perovskite oxides as SrTiO3, BiFeO3 and NdGaO3, the eonversion relationships of different perovskite crystal structures were investigated by using transmission electron microscopy （TEM）, simulation with JEMS software, etc. The orientational transformation matrices were obtained though theoretical derivations on the orientation conversion among eubie, orthorhombic and rhombohedral perovskite structures, which is confirmed by the results of electron diffraetion patterns （ EDPs）, simulation and high resolution TEM. Our work provides a way to diseussion the distorted perovskite structures with the pseudo-cubic structure consistently.