Abstract: A novel composite superconductor includes a superconducting material and a normal conducting material. The composite superconductor has a number of closely spaced grooves on a surface being in contact with a refrigerant, and a number of ridges spaced apart from each other by the grooves and having acutely tapered ends. The surfaces of the grooves and the ridges are coated with a thin film of metal or its compound having higher heat resistance than that of the surface of the composite superconductor. Consequently, a high critical heat flux in film boiling and a high cooling capability can be provided, thereby making it possible to decrease the sectional area of the normal conducting material, to increase the effective current density and to miniaturize the size of a magnet.

Abstract: Apparatus for applying chemical plating to inner surfaces of tubular members including a tank for storing a plating solution, a table for supporting a plurality of tubular members to be simultaneously plated, a plating solution distributing member connected to the storage tank via a plating solution supply line mounting a pump, and a plating solution collecting member connected to the storage tank via a plating solution return line. To provide a liquidtight seal, each tubular member to be plated is connected at its plating solution inlet end to the distributing member through a first connector and at its plating solution outlet end to the collecting member through a second connector. Each tubular member supported on the table, which is suitably inclined to allow hydrogen gas to be released through the plating solution outlet end of each tubular member to be plated, is encased in a supporting member formed of insulating material and comprising detachably attached two halves.