The elements of ferrite magnet are ferricoxide barium strontium . ferrite has highter coercive force and highter resistance to bedemagnetized and oxidized than other non - rare earth permanent magnets . the biggest advantage of such magnet is their low cost . it is widely used from motors and loudspeakers to toys and craft etc . . 铁氧体由氧化铁、钡、锶等元素组成，与其它非稀土磁钢相比，铁氧体的矫顽力和抗腐性都比较好，尤其它的低成本更是其它磁钢所无法比拟的。它被广泛应用于从电机、扬声器到玩具、工艺品等各个领域
In this paper , we have prepared soft magnetic mnzn ferrites with high thermal stability and low coercive force using sol - gel citrate auto - combustion method successfully , and investigated on how this process affected the magnetic properties of soft magnetic mnzn ferrites . sol - gel auto - combustion method is a new technology , combining ordinary sol - gel process with self - propagating at high temperature 本文主要用溶胶?凝胶柠檬酸盐自燃烧法( sol - gelauto - combustion )来制备软磁锰锌铁氧体，探究了该方法及工艺条件对软磁铁氧体性能的影响，并制备出低温度系数和低矫顽力的软磁锰锌铁氧体。
According to study on magnetic parameters of the bounded ndfeb magnets : coercive force ( hc ) , residual magnetism intensity ( br ) , ( bh ) max . the residual magnetism intensity ( br ) and ( bh ) max of the bounded ndfeb magnets have not been evidently changed between that of cladded and non - cladded ndfeb magnetic powders 能够改善ndfeb磁体的导电性能的目的。浙江工业大学硕士学位论文包覆前后的粘接ndfeb磁体的矫顽力有不同程度地降低;而最大磁能积和剩余磁感应强度却变化不大。
Design engineers now selecting pmbldc motors over conventional dc or induction motor drives for the following reasons : 1 ) the absence of brushes results in an essentially maintenance free operation and eliminates the undesirable effects of commutation such as sparks , brush - loss , radio - frequency interference , etc . 2 ) the low inertia of the rotor enhances the quality of the mechanical response of the motor , shortening the acceleration and deceleration time . 3 ) utilizing rare - earth permanent magnet materials with high coercive force results in substantially higher efficiency than their counterpart with brushes of the same size . 4 ) because of the absence of commutation segments , the stator construction is simple 现在的工程师们更为青睐永磁无刷直流电动机是因为以下几点原因： 1 )去除了电刷的永磁无刷直流电动机彻底地免除了维护而且消除了我们不希望的由于换向带来的火花、电刷损耗以及无线电干扰等等； 2 )低转动惯量的转子提高了电机机械响应的质量，从而缩短了电机加速和减速的时间； 3 )高矫顽力稀土永磁材料的使用使得同样尺寸的永磁无刷直流电动机比传统的直流电动机效率高； 4 )由于没有机械换向部分，定子的结构简单了。
The researching results of the paper is that administrative guidance is a new - style and feeble administrative behavior taken by administrative organizations . for the behavior there is no legally coercive force , it must be ruled by law . administrative guidance must be controlled by material law , procedural law and remedies , which make administrative guidance consummate 本文的研究结论:本文认为行政指导是行政机关依职权行驶的一种弱权力性行政行为,对于这种行为尽管不具有法律上的强制力,但仍然要纳入法治化进程,对行政指导要从实体法、程序法及事后救济三维一体的方法对其进行法控制,促进我国行政指导制度的完善。
When the doping amount of these four rare earths is lower , coercive force of la and sm - doped barium ferrite powders shows a similar regularity , that is , there exists a minimum , whereas there exists a maximum in nd and gd - doped barium ferrite powders . when the doping amount is higher , coercive force increases greatly with the increasing of the doping amount 样品的矫顽力在掺杂量较低的范围内出现一个极值( la和sm掺杂时为极小值， nd和gd掺杂时为极大值) ；在掺杂量较高的范围内，矫顽力随掺杂量的增加而大幅度增大。
