There is provided a method of forming a permanent magnet system, the method including: determining one or more types of geometrical parameters for forming an array of magnet ring pairs including a first subarray of first magnet rings and a second subarray of second magnet rings spaced apart from the first subarray of the first magnet rings along a longitudinal axis; and forming the array of magnet ring pairs based on the determined one or more types of geometrical parameters, whereby the above-mentioned determining one or more types of geometrical parameters for forming the array of magnet ring pairs is based on a genetic algorithm. There is also provided a corresponding permanent magnet system, such as formed by the method.

A magnet array is disclosed comprising a plurality of polyhedral magnets arranged in a Halbach cylinder configuration, the centers of individual ones of the plurality of polyhedral magnets being arranged substantially in a plane in a magnet rack, the plurality of the polyhedral magnets at least partly enclosing a testing volume, and comprising a first plurality of polyhedral magnets arranged in a Halbach cylinder configuration and a second plurality of polyhedral magnets arranged in a non-Halbach configuration. In another aspect, a magnet array is disclosed comprising a first subset and a second subset of polyhedral magnets having different coercivities. In yet another aspect, a magnet array is disclosed wherein a subset of the centers of the individual ones of the plurality of polyhedral magnets are laterally displaced from a nominal position in the magnet rack to counteract a magnetic field gradient of the magnet array.

A method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

A magnetic field device, with a first magnet, a first ferromagnetic element positioned adjacent to the first magnet, a second magnet, a second ferromagnetic element positioned adjacent to the second magnet and relative to the first ferromagnetic element to create a gap between the first ferromagnetic element and the second ferromagnetic element, and a third magnet positioned between the first ferromagnetic element and the second ferromagnetic element and within the gap.

A method of producing a permanent magnet shim configured to improve a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The method comprises determining deviation of the B.sub.0 magnetic field from a desired B.sub.0 magnetic field, determining a magnetic pattern that, when applied to magnetic material, produces a corrective magnetic field that corrects for at least some of the determined deviation, and applying the magnetic pattern to the magnetic material to produce the permanent magnet shim. According to some aspects, a permanent magnet shim for improving a profile of a B.sub.0 magnetic field produced by a B.sub.0 magnet is provided. The permanent magnet shim comprises magnetic material having a predetermined magnetic pattern applied thereto that produces a corrective magnetic field to improve the profile of the B.sub.0 magnetic field.

Various communication systems may benefit from improved voice call support. For example, it may be helpful for a user equipment in a first radio access technology that may not support voice calls to initiate a voice call with a second radio access technology. A method includes initiating a voice call between a user equipment to an entity in a second radio access technology cell. The user equipment is located in a first radio access technology cell. The method also includes registering the user equipment with the second radio access technology cell. In addition, the method includes conducting the voice call with the entity via the second radio access technology cell.

A magnetic field device, with a first magnet, a first ferromagnetic element positioned adjacent to the first magnet, a second magnet, a second ferromagnetic element positioned adjacent to the second magnet and relative to the first ferromagnetic element to create a gap between the first ferromagnetic element and the second ferromagnetic element, and a third magnet positioned between the first ferromagnetic element and the second ferromagnetic element and within the gap.

An assembly for providing a B.sub.0 magnetic field for a magnetic resonance imaging (MRI) system, the assembly comprising: a plurality of ferromagnetic segments positioned to form: a bore extending along a common longitudinal direction, and a first gap, on a first side of the bore, to accommodate at least one first gradient coil, wherein at least some of the plurality of ferromagnetic segments are positioned on one side of the first gap and at least some others of the plurality of ferromagnetic segments are positioned on another side of the first gap.

Some variations provide a permanent-magnet structure comprising: a region having a plurality of magnetic domains and a region-average magnetic axis, wherein each of the magnetic domains has a domain magnetic axis that is substantially aligned with the region-average magnetic axis, and wherein the plurality of magnetic domains is characterized by an average magnetic domain size. Within the region, there is a plurality of metal-containing grains characterized by an average grain size, and each of the magnetic domains has a domain easy axis that is dictated by a crystallographic texture of the metal-containing grains. The region has a region-average easy axis based on the average value of the domain easy axis within that region. The region-average magnetic axis and the region-average easy axis form a region-average alignment angle that has a standard deviation less than 30° within the plurality of magnetic domains. Many permanent-magnet structures are disclosed herein.

There is provided a method of forming a permanent magnet system, the method including: determining one or more types of geometrical parameters for forming an array of magnet ring pairs including a first subarray of first magnet rings and a second subarray of second magnet rings spaced apart from the first subarray of the first magnet rings along a longitudinal axis; and forming the array of magnet ring pairs based on the determined one or more types of geometrical parameters, whereby the above-mentioned determining one or more types of geometrical parameters for forming the array of magnet ring pairs is based on a genetic algorithm. There is also provided a corresponding permanent magnet system, such as formed by the method.