Abstract: A portable computer includes a main body containing a large number of electronic parts, a display panel including a flat display device and pivotal between a first position overlapping the main body and a second position separated from the main body, a hinge mechanism for pivotally coupling the main body and the display panel, a lock mechanism which non-pivotally locks the main body and the display panel at the first position of the display panel, and can be manually released, and a photosensor unit for detecting the position of the display panel with respect to the main body so as to cut off power supply to the display panel when the display panel is located at the first position, and to allow power supply to the display panel when the display panel is located at the second position.

Abstract: A superconducting magnet comprising a superconducting coil for generating a magnetic field when current flows therethrough and a vacuum heat insulation vessel storing and maintaining therein the coil at a cryogenic temperature, said vacuum heat insulation vessel having a part, such as a cylindrical outer wall, made of a ferromagnetic material which provides a path of high magnetic permeability for outwardly-directed flux lines of the magnetic field generated by said coil to reduce the spread of the flux lines and weaken the magnetic field outside the vessel.