Wang Suyu

A scheme of Maglev vehicle using high T/sub c/ bulk superconducters

High T/sub c/ superconductors are highly attractive because they can operate at liquid nitrogen temperature. The high performance of high T/sub c/ bulk superconductors is exciting to people in the application research work on superconducting magnetic levitation (Maglev) vehicle. The Maglev concept using high T/sub c/ bulk superconductors has been demonstrated by the Beijing Small Model. In this paper, schemes relating to the use of high T/sub c/ YBaCuO superconducting bulk materials for Maglev vehicle are discussed. First, the YBaCuO bulk superconductors are arranged above the rail using NdFeB permanent magnets. The second scheme is the electromagnetic suspension (EMS) Maglev vehicle using high T/sub c/ superconducting permanent magnets (SCPM) or high T/sub c/ superconducting wire. The third is the EMS Maglev using high T/sub c/ SCPM. The third scheme is chosen after making a comparison. The key problems of the EMS Maglev vehicle using high T/sub c/ SCPM are discussed.

A method for frequency measurements of submillimeter wave using Josephson effect

A method for directly measuring the absolute frequency of a long pulse period and ultrashort pulse duration in the submillimeter band using a superconducting technique is presented. The frequency of these pulses cannot be measured by the AC Josephson effect, because their frequency spectrum is very complex. The method makes use of superconductive active and passive devices, namely, tapped delay lines, Josephson junctions for switching, and Josephson junctions for measuring frequency, and all devices constitute a whole. This method can directly accomplish real time frequency measurement of the submillimeter wave pulse signal.