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In a radially anisotropic sintered magnet of annular shape, the remanence
in a radial direction of the annulus increases and decreases at intervals
of 90.degree. in a circumferential direction of the annulus, and the
remanence in a radial direction over the entire circumference of the
annulus has a maximum of 0.95-1.60 T and a minimum equal to 50-95% of the
maximum. In a permanent magnet motor comprising a plurality of stator
teeth, the radially anisotropic annular sintered magnet is incorporated
after it is magnetized in 4n poles (wherein n is an integer of 1 to 20)
so that the boundary between N and S poles is located within the range
that is centered at the radial direction where the remanence exhibits the
minimum and extends .+-.10.degree. therefrom in a circumferential
direction. The radially anisotropic annular sintered magnet undergoes
neither fracture nor cracking during the sintering and aging/cooling
steps even when it is shaped to a low inner/outer diameter ratio and has
satisfactory magnetic properties. A permanent magnet motor comprising the
radially anisotropic annular sintered magnet is inexpensive and of high
performance.
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< Borazine-based resin, and method for production thereof, borazine based resin composition, insulating coating and method for formation thereof, and electronic parts having the insulating coating
> Photomask blank, photomask and fabrication method thereof
> Half-tone stacked film, photomask-blank, photomask and fabrication method thereof
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~ 00564
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