Systems and methods for reversing a magnetization in a ferromagnet include a nanometer-scale cylindrical ferromagnetic sample having a height to diameter aspect ratio on the order of 2 or greater. A temporally-varying external field comprising an r.f. Pi pulse is applied to the ferromagnetic sample to cause a precession magnetization vector inclined at an angle with respect to the longest axis of the ferromagnetic sample to continuously rotate around the longest axis. One or more parameters of the temporally-varying external field is continuously adjusted based on at least magnetization dynamics of the ferromagnetic sample and/or an angular dependence of a precession frequency of the ferromagnetic sample.

Systems and methods for reversing a magnetization in a ferromagnet include a nanometer-scale cylindrical ferromagnetic sample having a height to diameter aspect ratio on the order of 2 or greater. A temporally-varying external field comprising an r.f. Pi pulse is applied to the ferromagnetic sample to cause a precession magnetization vector inclined at an angle with respect to the longest axis of the ferromagnetic sample to continuously rotate around the longest axis. One or more parameters of the temporally-varying external field is continuously adjusted based on at least magnetization dynamics of the ferromagnetic sample and/or an angular dependence of a precession frequency of the ferromagnetic sample.

A device (2) for demagnetizing and for measuring the magnetic signature of a stationary hull (4) and for simulating a magnetic field, including a demagnetization coil assembly (8), a magnetic field sensor assembly (10) and a simulation coil assembly (12a, 12b, 12c), which can be positioned next to the hull (4) in a horizontal manner on one side and the cross-sectional areas of the demagnetization coils (8) and of the simulation coils (12a, 12b, 12c) being disposed in the longitudinal direction of the hull (4) with horizontally oriented surface normals. The demagnetization coils (8) produce an alternating magnetic field; the simulation coils (12a, 12b, 12c) produce a stationary simulated magnetic field in all three dimensions.

A method of fabricating a shape-changeable magnetic member comprising a plurality of segments with each segment being able to be magnetized with a desired magnitude and orientation of magnetization, to a method of producing a shape changeable magnetic member composed of a plurality of segments and to a shape changeable magnetic member.

A method of fabricating a shape-changeable magnetic member comprising a plurality of segments with each segment being able to be magnetized with a desired magnitude and orientation of magnetization, to a method of producing a shape changeable magnetic member composed of a plurality of segments and to a shape changeable magnetic member.

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.

Provided are a magnetorheological fluid rotational load device and a method of controlling the same. The magnetorheological fluid rotational load device includes a housing, a yoke fixed in the housing, a shaft rotatably mounted at the center in the housing, one or more rotation rings connected to the shaft to rotate in association with rotation of the shaft, a coil disposed in the housing, a magnetorheological fluid filling the housing.

Provided are a magnetorheological fluid rotational load device and a method of controlling the same. The magnetorheological fluid rotational load device includes a housing, a yoke fixed in the housing, a shaft rotatably mounted at the center in the housing, one or more rotation rings connected to the shaft to rotate in association with rotation of the shaft, a coil disposed in the housing, a magnetorheological fluid filling the housing.

A demagnetization method for a multilayer shielding apparatus is provided. In the demagnetization method, the demagnetization is realized on the basis of a demagnetization coil system. The demagnetization coil system includes a plurality of turns of demagnetization coils (2), a plurality of connection wires and a power supply module. The multilayer shielding apparatus includes at least two layers of shielding bodies (1); all the layers of shielding bodies (1) are sleeved layer by layer from inside to outside; a plurality of turns of demagnetization coils (2) are wound on each layer of shielding bodies (1) at intervals; and one half of each turn of demagnetization coils (2) is located inside the wound shielding bodies (1), and the other half is located outside the wound shielding bodies (1). Each demagnetization coil (2) is connected to the power supply module through the corresponding connection wire.

A device for accommodating and magnetizing a tissue-penetrating medical device of various lengths, with or without a cover covering a portion or the entirety of the tissue-penetrating medical device, is disclosed including a sleeve member having an open proximal end, a distal end, an inner surface, an outer surface having a graduated injection depth gauge to indicate needle penetration depth when the cover is placed into a magnetizer, and a hollow body extending between the proximal end and the distal end to form a protective closure over a shaft of a tissue-penetrating medical device. A device having one or more magnetizing elements sectioned into a plurality of movable segments pivoting around an axis to accommodate needles with different lengths is also disclosed. Also disclosed is a device having one or more magnetizing means mounted on a movable element to magnetize needles of various lengths.