中文摘要：

单边开放式永磁型磁共振磁体结构的研究是一个全新的电工课题。本文基于鞍点理论，探索永磁磁体外部一侧构建均匀磁场区域的可行性问题，并根据可行性要求，通过对单边电流线圈结构的分析，给出一种单边永磁磁体结构方案，并应用一种数值法与半解析法相结合的混合算法分析这种特殊磁体结构的磁场。数值仿真结果表明，本文提出的永磁磁体结构能够较好地在磁体外部构建符合成像要求的薄片形磁场区域。鞍点理论在单边开放式MRI磁体结构设计中的成功应用，为单边永磁MRI磁体结构的分析提供了可靠的理论依据，而磁体外部特殊磁场区域的成功构建，为介入式磁共振系统的研究准备了条件。

英文摘要：

It is a new problem in terms of magnet designs to generate a slice region with highly homogeneous magnetic field outside the permanent magnet. In this paper, the feasibility about the problem was discussed on the basis of the theory of saddle point. Considering the unilateral coils structure, a kind of unilateral permanent magnet structure was proposed and analyzed by use of a hybrid method, which is a combination of numerical method and semi-analytical method. The simulation results show that the proposed magnet structure can generate a slice region with homogeneous magnetic field outside the permanent magnet. The feasible analysis on the magnet design and the successful achievement of the magnet model build the foundation for the scientific research on the open magnetic resonance imaging （MRI） device and the minimally invasive surgical procedures.