| 摘要 |
PCT No. PCT/FR87/00392 Sec. 371 Date Apr. 14, 1989 Sec. 102(e) Date Apr. 14, 1989 PCT Filed Oct. 13, 1987 PCT Pub. No. WO88/02923 PCT Pub. Date Apr. 21, 1988.Industrial problems concerning the production of a field of uniform and traverse induction are solved by providing a cylindrical magnet with magnetic blocks of which the internal magnetization is either radial or tangential to the cylinder. Such an arrangement facilitates the fabrication and the magnetization of the blocks. A radial or tangential magnetization distribution produces a transverses field only if the magnetization modulus varies respectively with the cosine or the sine of the localization angle of the block with respect to the direction of induction to be produced. By combining both structures, it is even possible to obtain a magnet having a zero bipolar moment. The variation of the magnetization modulus is obtained by providing composite magnetic bricks. They comprise plates of magnetic materials which are coupled to non-magnetic plates in a proportion dependeing on the reduction of magnetization to be achieved. Such a magnet applies to imaging by nuclear magnetic resonance in the medical field.
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