中文摘要：

提出一种设计永磁型核磁共振磁体磁极形状的优化方法，该方法用水平集函数隐式地描述材料界面，通过连续性形状灵敏度分析，可得到隐式描述的材料界面上各点的演化速度，而水平集的演化由哈密尔顿一雅可比方程控制，该方程可通过有限差分法求解。设计结果表明了该优化算法的有效性。

英文摘要：

A method to optimize the shape of pole is presented for permanent-type nuclear magnetic resonance （NMR）. An implicit interface representation depicts the interface by means of level set function. The velocity of each point on the implicit interface is given with the continuum shape sensitivity analysis, the evolution of this level set is controlled by a Hamilton-Jacobi equation which is solved by using finite difference scheme. The design result shows the effectiveness of the proposed algorithm.