论文标题
在梯度和均匀磁场下的悬浮铁磁纳米颗粒的定向运输
Directed transport of suspended ferromagnetic nanoparticles under both gradient and uniform magnetic fields
论文作者
论文摘要
受梯度和均匀磁场的悬浮铁磁颗粒经历了田间梯度产生的平移力，也经历了磁场强度产生的旋转扭矩。尽管均匀场并不促进力，但它仍影响这些颗粒的翻译运动。之所以发生这种情况，是因为翻译力取决于粒子磁化的方向，这又取决于场的强度。为了研究这种影响，在低雷诺数近似值中引入并解决了一组最小的方程式，描述了纳米化铁磁颗粒的耦合平移和旋转运动。轨迹分析表明，根据纳米颗粒的初始位置，其定向运输有四个方案。确定与不同动力学机制相对应的初始位置的间隔，确定其对均匀磁场的依赖，并证明该场对有向运输的强大影响。还讨论了均匀磁场控制悬浮铁磁纳米颗粒的分离的能力和效率。
The suspended ferromagnetic particles subjected to the gradient and uniform magnetic fields experience both the translational force generated by the field gradient and the rotational torque generated by the fields strengths. Although the uniform field does not contribute to the force, it nevertheless influences the translational motion of these particles. This occurs because the translational force depends on the direction of the particle magnetization, which in turn depends on the fields strengths. To study this influence, a minimal set of equations describing the coupled translational and rotational motions of nanosized ferromagnetic particles is introduced and solved in the low Reynolds number approximation. Trajectory analysis reveals that, depending on the initial positions of nanoparticles, there exist four regimes of their directed transport. The intervals of initial positions that correspond to different dynamical regimes are determined, their dependence on the uniform magnetic field is established, and strong impact of this field on the directed transport is demonstrated. The ability and efficiency of the uniform magnetic field to control the separation of suspended ferromagnetic nanoparticles is also discussed.
