Abstract: A magnet apparatus for use in magnetic resonance imaging systems comprises a superconducting coil which produces a main magnetic field in a working volume defined in the bore in which a patient is accommodated and a cryostat accommodating the superconducting coil and keeping the superconducting coil in the superconducting state. This cryostat includes only one thermal radiation shield and is configured with a smaller volume than that of conventional cryostats with no reduction in the heat insulation effects. Therefore, the dimensions of the bore are determined to comply with 1.0.ltoreq.L/B<1.9 where L is the length along the Z axis of the bore and B is its diameter. Thus, the length L along the Z axis of the bore is determined to be relatively short while the dimensions of the working volume necessary for diagnosis is secured in the bore, with the result that the oppressive sensation that the patient has in the bore is lessened.

Abstract: A magnetic resonance system having a compact magnet configuration for generating a static magnetic field. The magnet and platform carrying the patient to be examined are so arranged as to be arbitrarily moved relative to one another. The resulting small size field-homogeneous space may be freely moved to various portions of the patient body to permit a wide range of whole body measurements.

Abstract: A magnetic shield for a magnetic resonance magnet, the shield being made of magnetic material, surrounding the magnetic resonance magnet, the shield having at least two units which are so constructed as to be assembled with essentially horizontal movements of the units.

Abstract: A pair of coils are arranged to surround a crucible for storing a melt. The axes of the coils are vertical and the melt is heated by a heater. When the coils are energized such that the magnetic fluxes thereof oppose each other along the axial direction, a magnetic field having an isomagnetic field distribution of an elliptical shape is formed. When the energization current is properly selected, a magnetic field for restricting thermal convection of the upper melt portion is formed, while, conversely, thermal convection of the lower melt portion occurs. When the melt surface level is lowered upon pulling of the single crystal, a magnetic field is controlled such that the boundary between the thermal convection restriction region and the thermal convection region is, similarly, lowered. Since thermal convection is restricted near the solid-liquid interface layer, the single crystal can be stably grown. In the lower melt portion, thermal convection is present such that the lower melt is stirred.

Abstract: A single crystal pulling system including a single crystal pulling apparatus, an electromagnet, and an electromagnet moving mechanism, wherein the single crystal pulling apparatus pulls a seed crystal from a single crystal material melt contained in a crucible at a specified constant speed. The electromagnet is disposed at the outer periphery of the crucible so as to apply a predetermined required strength of magnetic field to the crystal-melt interface of the melt. The magnet moving mechanism moves the electromagnet in a vertical direction with respect to the crucible as the level of the crystal-melt interface is lowered during seed growth so that a predetermined required strength of magnetic field is always applied to the crystal-melt interface.

Abstract: A single crystal manufacturing apparatus has a pulling mechanism and a magnetic field generating unit. The pulling mechanism grows a single crystal by inserting a seed crystal into a melting liquid of a single crystal raw material and pulling the seed crystal from the melting liquid at a predetermined speed. The generating unit has a pair of superconductive magnets for applying a magnetic field to the melting liquid. The magnetic field applied from the magnets suppresses a thermal convection in the vicinity of the surface of the melting liquid and allows the thermal convection in the region of the melting liquid below the surface thereof.

Abstract: A cold insulation vessel comprises an inner chamber in which cryogen is enclosed, an outer chamber to enclose this inner chamber and a shield member against heat radiation which is provided between the inner chamber and the outer chamber. This vessel is provided to hold a superconducting coil which is enclosed in the inner chamber at a very low temperature. A power lead is provided to supply an exciting current to this superconducting coil. A recondenser is provided to recondense the evaporated gas of the cryogen in the inner chamber. The small refrigerator means has a plurality of refrigeration stages which are directly coupled to the power lead and the recondenser.