12)This tendency of flux density to lag behind the field intensity when the ferromagnetic material is in a symmetrically cyclically magnetized condition is called hysteresis and the closed curve abcdea is called a hysteresis loop.
13) Note that the magnetomotive force of the coil produces a flux which is confined to the iron and to that part of the air having effectively the same cross-sectional area as the iron.
14) In spite of the presence of air gaps it happens that the space occupied by the magnetic field and the space occupied by the ferromagnetic material are practically the same.
15) Usually this is because air gaps are made as small as mechanical clearance between rotating and stationary members will allow and also because the iron by virtue of its high permeability confines the flux to itself as copper wire confines electric current or a pipe restricts water.
16) On this basis the three-dimensional field problem becomes a one-dimensional circuit problem and leads to the idea of a magnetic circuit. Thus we can look upon the magnetic circuit as consisting predominantly of iron paths of specified geometry which serves to confine the flux, air gaps may be included.
你们是在哪里找的翻译工具啊
有的还很好 可是有的根本就不想一句中国话啊