We adopted a combination of pieces of permanent magnets and a single-channel (SC) shim coil to shim the magnetic field in a magnetic resonance imaging system dedicated for skeletal age assessment of children. The target magnet was a 0.3-T open and compact permanent magnet tailored to the hand imaging of young children. The homogeneity of the magnetic field was first improved by shimming using p...

The ready availability of very strong permanent magnets in the form of rare-earth magnetic alloys such as neodymium-iron-boron has lead to renewed interest in one of the oldest types of electric motors the homopolar motor. The ease with which a demonstration homopolar motor can now be built and operated when neodymium magnets are used is quite remarkable. In this paper two recent types of simpl...

An analytical expression is derived for the magnetic field of a two-dimensional periodic circular array of head-to-head permanent magnets, assuming there is either no gap between the magnets or that they are separated by a non-magnetic pole-piece. Some more general symmetry properties are described. The force experienced by the magnets is calculated and an analytical approximation is derived. W...