Abstract: A metal nanonetwork includes metal nanostructures that are joined by metallic bond. The joined part between the metal nanostructures includes a fillet part. In the joined part between the metal nanostructures, the distance between the central axis of one metal nanostructure and the central axis of another metal nanostructure is smaller than the sum of the radii of both metal nanostructures. The metal nanostructure is a metal nanowire. A first method for producing the metal nanonetwork includes a process of forming an oxide film on the outermost surface of the metal nanostructure, and a process of reducing the oxide film at the joined parts of a plurality of the metal nanostructures to thereby join the metal nanostructures.

Abstract: A superconducting cable for alternating current, comprising conductor layers formed by a plurality of tape-shaped superconducting wires wound around a center member, an electric insulating layer formed outside the conductor layers, and a plurality of shielding layers formed outside the insulating layer, wherein, the conductor layers are formed, where N is a number of layers in the conductor layers and expressed by an integer, by gradually increasing a winding pitch of conductor layers in the same direction from an inner first layer to an N/2 layer when the number of layers is even, or from an inner first layer to a (N−1)/2 layer when the number of layers is odd, and then by gradually decreasing a winding pitch of conductor layers in an opposite direction to the inner layers from a N/2+1 layer to an N layer when the number of layers is even, or from a (N+1)/2 layer to an N layer when the number of layers is odd.

Abstract: A superconducting cable for alternating current, comprising conductor layers formed by a plurality of tape-shaped superconducting wires wound around a center member, an electric insulating layer formed outside the conductor layers, and a plurality of shielding layers formed outside the insulating layer, wherein