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Applied Superconductivity, IEEE Transactions on

Issue 4 • Date Dec 2000

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Displaying Results 1 - 4 of 4
  • Room-temperature testing for high critical-current-density Josephson junctions

    Publication Year: 2000 , Page(s): 1669 - 1672
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (68 KB)  

    This paper demonstrates that room-temperature resistance measurements can accurately predict the critical current and normal resistance of high critical-current-density junctions. We fabricated high critical-current-density (/spl sim/200 /spl mu/A//spl mu/m/sup 2/=20 kA/cm/sup 2/) Nb/Al/AlO/sub x//Nb Josephson junctions in cross-bridge Kelvin resistor (CBKR) test structures and measured their electrical characteristics both at 4.2 K and at room temperature. We developed a two-dimensional mathematical model of the CBKR test structure with two resistive wiring layers in order to characterize the effect of current crowding on the room-temperature measurements. We then used the model to remove the effect of current crowding from the room-temperature measurements and correlated the values of these measurements to the electrical properties of the junctions at 4.2 K. We also identified test-structure-design rules that guarantee current crowding is negligible. View full abstract»

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  • Active permanent magnet support for a superconducting magnetic-bearing flywheel rotor

    Publication Year: 2000 , Page(s): 1673 - 1677
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB)  

    This paper proposes a novel active permanent magnet support approach to improve the lateral stiffness of a superconducting magnetic-bearing flywheel rotor system. An actual flywheel rotor system levitated with high-temperature superconducting magnetic bearings is modeled and then analyzed with a moving permanent magnet support placed at the top of the rotor. The active support principle defined in this study is based on moving the permanent magnet support 180/spl deg/ out of the phase with the rotor displacement. A complete dynamical equation of the flywheel rotor is derived including gyroscopic effects. Analysis showed the active support of the flywheel rotor with additional permanent magnet movements decreased the amplitude of flywheel rotor vibration considerably. View full abstract»

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  • Author index

    Publication Year: 2000 , Page(s): 1678 - 1699
    Save to Project icon | Request Permissions | PDF file iconPDF (204 KB)  
    Freely Available from IEEE
  • Subject index

    Publication Year: 2000 , Page(s): 1699 - 1731
    Save to Project icon | Request Permissions | PDF file iconPDF (261 KB)  
    Freely Available from IEEE

Aims & Scope

IEEE Transactions on Applied Superconductivity contains articles on the applications of superconductivity and other relevant technology.

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Meet Our Editors

Editor-in-Chief
Britton L. T. Plourde
Syracuse University
bplourde@syr.edu
http://www.phy.syr.edu/~bplourde