Abstract: An MgB2-based superconducting wire for a liquid hydrogen fluid level sensor which can maintain an unimmersed portion of the MgB2-based superconducting wire for a liquid hydrogen fluid level sensor in a non-superconducting state even without heating the unimmersed portion is provided. A wire for a liquid hydrogen fluid level sensor comprises an MgB2-based superconductor which contains Mg, B, and Al. The critical temperature at which the electrical resistance becomes essentially zero is 20-25 K, and the transition width, which is the difference between the temperature at which the electrical resistance begins to decrease toward zero and the critical temperature, is at most 5 K.

Abstract: A wire saw which has excellent cutting ability and which is not easily clogged by chips formed by cutting is provided. It has a body 6 having a first metal wire 1 which is made of a cobalt-based alloy, two second metal wires 2a and 2b which are made of a cobalt-based alloy, and three third metal wires 3a-3c which are made of a cobalt-based alloy and are wound on the first metal wire 1. The second metal wires 2a and 2b are helically wound on each of the third metal wires 3a-3c in opposite directions so as to cross each other. Cutting teeth are constituted by projections 8 which are formed by the crossing points of the two second metal wires 2a and 2b.