搅拌子和搅拌棒的改进与制作

介绍了带轮搅拌子和玻塑搅拌棒的制作，方法简便，材料易得，价格低廉，使用范围广泛。通过对７届学生指导其制作使用，效果很好。不仅适用于教学、科研，也便于在大、中学中推广，指导学生自己制作，能有效地培养他们自力更生意识，提高他们的实验技能     

新学说:磁场空间分布的新概念

 在磁场空间分布的传统概念中,认为一条棒状磁铁的两端磁性最强,称为磁极,如果把棒状磁铁悬挂起来自由转动,磁棒指北的一端称为北极(N极),指南的一端称为南极(S极),棒状磁铁的中部几乎无磁性,棒状磁铁周围磁场的分布是空间位置的函数,磁场由S极向着N极方向,如图1(a)所示.地球象一条形磁铁,也有S极和N极,地球外部磁场的空间分布如图1(b)所示.     

均匀磁化永磁棒的磁场

本文综合运用分子电流观点及磁荷观点,系统地计算了沿轴向、横向及其它任意方向均匀磁化的有限长永磁棒在轴线上的磁场以及无限长永磁棒在全空间的磁场.     

基于数字示波器的综合性实验设计

介绍一个综合性实验的设计．用数字示波器与一个简单的装置配套,通过对同一个物理现象的多角度分析,实现了对法拉第电磁感应定律的验证;应用电磁感应测定了重力加速度;同时对磁棒的磁感应强度分布做出了定性描述．     

Changes in the natural frequency of a ferromagnetic rod in a magnetic field due to magnetoelastic interaction

Based on the magnetoelastic generalized variational principle and Hamilton＇s principle, a dynamic theoretical model characterizing the magnetoelastic interaction of a soft ferromagnetic medium in an applied magnetic field is developed in this paper. From the variational manipulation of magnetic scale potential and elastic displacement, all the fundamental equations for the magnetic field and mechanical deformation, as well as the magnetic body force and magnetic traction for describing magnetoelastic interaction are derived. The theoretical model is applied to a ferromagnetic rod vibrating in an applied magnetic field using a perturbation technique and the Galerkin method. The results show that the magnetic field will change the natural frequencies of the ferromagnetic rod by causing a decrease with the bending motion along the applied magnetic field where the magnetoelastic buckling will take place, and by causing an increase when the bending motion of the rod is perpendicular to the field. The prediction by the mode presented in this paper qualitatively agrees with the natural frequency changes of the ferromagnetic rod observed in the experiment.