Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils and at least one additional superconductive main coil. A pair of generally-non-permanently-magnetized ferromagnetic rings is spaced radially inward and apart from the superconductive main coils. The ferromagnetic rings allow the design of a shorter MRI magnet because the ferromagnetic rings overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: The present invention relates to an electromagnet apparatus having a coil wound around a bobbin, a core fixed to and supported by the bobbin to cover at least a portion of the surface of the coil and having a slant serving as a first pole head, the force of which acts in a direction of the surface of the coil, and a rotatively supported around a center of winding of the coil around the bobbin and having a slant serving as a second pole head, the force of which acts in a direction of the surface of the bobbin, wherein the slant of the core and that of the rotor are disposed to face each other with a predetermined air gap maintained with which the rotor is able to attractively rotate with respect to the core.

Abstract: A solenoid valve assembly having a rapid assembly clip. The clip is a spring clip which is pivotally secured to a housing for the solenoid valve assembly. The clip engages an annular groove in an extending portion of a solenoid element, with the clip being appropriately shaped to engage the groove to retain the solenoid element in place in the housing. In the described form of the invention, the spring clip is a wire element which engages the annular groove on opposite sides. Where there is engagement, the wire element is curved to conform to and firmly seat in the annular groove.

Abstract: A refrigerator with a freezer section and a passage for the flow of ice through the closed freezer section door is provided with a solenoid-like actuator which is effective for quickly opening a related ice dispenser door upon initiation of the flow of ice, and which is effective for relatively slowly closing the related ice dispenser door to thereby assure that further ice will not pass into the passage after the ice dispenser door is closed.

Abstract: The invention provides a cylindrical permanent magnet unit suitable for application to gyrotrons. Essentially the magnet unit consists of two cylindrical permanent magnets which are coaxially aligned, and there is a space between the two cylindrical magnets. Each of the two cylindrical magnet is a coaxially juxtaposed assembly of a plurality of ring-like permanent magnets, and each ring-like magnet is constructed of a plurality of permanent magnet segments. In one of the two cylindrical magnets every ring-like permanent magnet is magnetized in radial directions from the inside toward the outside, and in the other every ring-like permanent magnet is magnetized in radial directions from the outside toward the inside. In the bore of the cylindrical magnet unit the magnetic field is in the direction of the longitudinal center axis of the bore.

Abstract: An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil. A generally annular-shaped permanent magnet array is associated with each coil assembly, being generally coaxially aligned with the associated coil assembly and being spaced radially inward and radially apart from the associated coil assembly's superconductive main coil. The permanent magnet arrays overcome the gross magnetic field distortions in the imaging volume of the superconductive main coils (created by the open space between the magnet's superconductive coil assemblies) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: A magnet system for a nuclear spin tomograph having at least one field producing magnet coil S.sub.1 with radius r.sub.s1 arranged in a middle plane which produces a homogeneous magnetic field in an investigational volume directed along a z-axis perpendicular to the middle plane, is characterized in that at least one, preferentially at least two, ferromagnetic rings R.sub.i with radius r.sub.Ri are provided in the middle plane concentric to the magnetic coil S.sub.1. A system of this kind can be substantially more compact in construction than conventional systems with equal produced field strength. In addition substantially reduced currents are required through the coil or coils for field production.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils. A pair of generally annular-shaped bucking coils, carrying electric current in a direction opposite to that of the superconductive main coils, is spaced radially inward and apart from the superconductive main coils. The bucking coils allow the design of a shorter MRI magnet because the bucking coils overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: An apparatus and a method for reducing VLF pulsating magnetic field generated by electronic devices to less than about 0.25 mG beyond about 20 inches from said device. The apparatus includes a closed inert circuit having a number of windings effective to accomplish the reduction.

Abstract: An open magnetic resonance imaging (MRI) magnet having first and second spaced-apart superconductive coil assemblies each including a toroidal-shaped coil housing containing a superconductive main coil in thermal contact with a cryogenic fluid contained in a dewar. Preferably, each main coil is located outside of and in solid-conduction thermal contact with its corresponding dewar (instead of inside the dewar). Preferably, a surrounding single (not double) thermal shield is cooled by liquid cryogen boil-off or by a cryocooler coldhead. All this allows the main coil to be located closer to the magnet's open space which reduces magnet cost by reducing the amount of coil needed for the same-strength magnetic field.

Abstract: A closed magnetic resonance imaging (MRI) magnet has a single superconductive coil assembly including a toroidal-shaped coil housing containing a pair of superconductive main coils and at least one additional superconductive main coil. A pair of generally annular-shaped permanent magnet arrays is spaced radially inward and apart from the superconductive main coils. The permanent magnet arrays allow the design of a shorter MRI magnet because the permanent magnet arrays overcome the gross magnetic field distortions in the imaging volume of the magnet (created by removing some of the additional longitudinally-outermost superconductive main coils, otherwise used in the magnet, to make the magnet shorter) to produce a magnetic field of high uniformity within the imaging volume.

Abstract: A normal conducting bending electromagnet having: a pair of pole pieces having respective pole piece faces, said pole pieces being; disposed with the pole piece faces thereof facing each other with a substantially constant gap therebetween; a magnetic field for forming a charged particle beam arc orbit, being generated in the gap between the pole pieces. A yoke coupled to the pole pieces for forming a closed magnetic circuit with the gap, and a pair of coils is provided for generating a magnetomotive force and generating magnetic fluxes in the magnetic circuit. At least one side wall of each of the pole pieces is slanted or stepped along a virtual slanted plane; along the magnetic path of the pole piece so as to gradually broaden the cross sectional area of the pole piece at the plane perpendicular to the magnetic path from the gap toward the yoke, the slanted side wall or the virtual slanted plane; having a slant angle in the range from 30.degree.

Abstract: A low-noise solenoid has an armature with a projecting ridge receivable within a groove in a pole piece. As the ridge enters the groove, the magnetic force which opposes a return spring decreases until there is equilibrium whereat the armature remains suspended without impacting upon the pole piece.

Abstract: A magnet assembly has a generally U-shape, the bight of the U including a permanent magnet which generates a magnetic field whose flux passes through a working volume defined between the arms of the U. The dimensions of the assembly are chosen such that: ##EQU1## where: L.sub.g is the length of the gap between the arms,L.sub.m is the length of the magnet,B.sub.r is the remnant field of the magnet, andB.sub.g is the field in the gap.

Abstract: A shielded and open magnetic resonance imaging (MRI) magnet having two spaced-apart, generally toroidal-shaped superconductive coil assemblies. Each coil assembly has a coil housing containing a generally annular-shaped superconductive main and a radially-outwardly spaced-apart shielding coil carrying electric currents in opposing directions. Preferably, supplemental shielding is provided with the addition of: a generally annular permanent magnet configuration internal to, or external of, the coil housings; a generally-non-permanently-magnetized external ferromagnetic shield having at least a portion positioned longitudinally between the coil housings, an external resistive coil; or combinations thereof.

Abstract: A method and apparatus for compressing magnetic flux to achieve high levitation pressures. Magnetic flux produced by a magnetic flux source travels through a gap between two high temperature superconducting material structures. The gap has a varying cross-sectional area to compress the magnetic flux, providing an increased magnetic field and correspondingly increased levitation force in the gap.

Abstract: A plurality of magnetic poles provided by using magnets are arranged in opposition to one another in pairs. The pairs of magnetic poles are arranged with two kinds of intervals between the adjacent magnetic poles. The two intervals have the relation of an irrational number ratio in accordance with the lining order of generalized Fibonacci series. The series of peak values of the magnetic field or the series of peak values of the double integral values of the magnetic field along the central axis of the magnetic circuit comprising the array of the magnets reside at the positions to satisfy the relation of generalized Fibonacci series.

Abstract: A gradient coil system for the production of a magnetic transverse gradient field G.sub.x in an NMR tomograph is presented. The main magnetic field B.sub.z is directed along the z-axis, the magnetic transverse gradient field G.sub.x along the x-axis, and the gradient coil system comprises four partial coils (S.sub.1x, S.sub.2x, S.sub.3x, S.sub.4x) each with two current connections (A.sub.1, A.sub.2). The coils are arranged mirror symmetrically with respect to the xy-plane (z=0) and mirror symmetrically with respect to the zy-plane and each partial coil contains only winding sections on an inner and an outer cylinder Z.sub.ix, Z.sub.ax about the z-axis as well as in a radial connecting plane V.sub.+x, V.sub.-x parallel to the xy-plane. The partial coils are configured in such a fashion that the winding sections on the inner and outer cylinder Z.sub.ix, Z.sub.ax are axially further removed from the xy-plane than the corresponding radial connecting planes V.sub.+x, V.sub.-x, and the axial separation d.sub.

Abstract: A three way system for providing controlled levitation or suspension in a magnet-superconductor system, including a current-carrying conductor (such as a coil) for affecting interactions in the magnet-superconductor system, for example by producing a magnetic field intercepting the superconductor, thereby affecting the flux penetration and/or flux pinning properties of the superconductor. By varying the magnitude of the control current the magnitude of the field produced by the coil varies which in turn varies the magnetic interactions in the magnet-coil-superconductor system. This provides a controllable and stable range of levitation, suspension distances, and rotation in the system. Any type II superconductor can be used, but particular advantages are obtained when high T.sub.c superconductors are used.

Abstract: An apparatus for making permanent magnet material magnetizes a body of material including a primary winding which has portions wound on a first core carrying current in a first direction creating a first field of flux and a secondary winding having portions wound on a second core wherein the secondary winding carries current in a second opposing direction to create a second field of flux. Since the currents are flowing in opposing directions, the secondary field of flux is directed to oppose the first field of flux. The result of this is that the magnetizer is capable of controlling the width of the pole to pole transition region for matching the stator geometry and thereby nearly eliminating cogging torque and reducing ripple torque.