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Magnesium diboride (MgB2) shows a wide application prospect in the field of low field DC application for its relatively simple structure and rather higher critical temperature than LTS. With the development of MgB2 composite superconductor manufacturing technology and cryogenic technology, developing conduction cooled superconducting MRI system with MgB2 composite superconductor is becoming increasingly feasible. An MgB2 superconducting magnet for MRI was developed. The MgB2 superconducting magnet is used to investigate the fundamental scientific problem of the MRI main magnet, including field uniformity and stability, influencing factors of MgB2 composite superconductor on field uniformity and stability. The superconducting magnet consists of 2 solenoids wound with MgB2 wire with the length of 60 m. The magnet has an outer diameter of 169 mm, an iron core diameter of 135 mm, and air gap of 32 mm. The superconducting magnet is fabricated and tested. The central magnetic field reaches 1.0 T when the current of the MgB2 magnet is 290 A. The central magnetic field is 0.39 T when the current of the MgB2 magnet is 100 A. In this paper, the minimum quench energy, the quench propagation velocity and the minimum propagation zone of the MgB2 composite conductor are measured. Main magnet for MRI with MgB2 composite superconductor is analysed and proposed, including magnet design and test results. By theoretical modeling and simulation, the detailed quench propagation of the magnet is further analysed. Finally, the stability criteria of conduction-cooled MRI magnet are established. [ABSTRACT FROM AUTHOR]

The critical performance of YBCO tape with inhomogeneous superconducting properties was simulated by use of a bad point distribution model and the Gaussian distribution model. The critical current and n value of the whole HTS tape was analysed. The reliability of the simulation was verified with the experimental data. The results of the two simulation models were compared each other. The influence of inhomogeneous properties on the critical performance of YBCO HTS tape was proved by simulation results which are helpful for the simulation of superconducting devices based on YBCO HTS tapes. [ABSTRACT FROM AUTHOR]

Magnesium diboride (MgB2) shows a wide application prospect in the field of low field DC application for its relatively simple structure and rather higher critical temperature than LTS. With the development of MgB2 composite superconductor manufacturing technology and cryogenic technology, developing conduction cooled superconducting MRI system with MgB2 composite superconductor is becoming increasingly feasible. An MgB2 superconducting magnet for MRI was developed. The MgB2 superconducting magnet is used to investigate the fundamental scientific problem of the MRI main magnet, including field uniformity and stability, influencing factors of MgB2 composite superconductor on field uniformity and stability. The superconducting magnet consists of 2 solenoids wound with MgB2 wire with the length of 60 m. The magnet has an outer diameter of 169 mm, an iron core diameter of 135 mm, and air gap of 32 mm. The superconducting magnet is fabricated and tested. The central magnetic field reaches 1.0 T when the current of the MgB2 magnet is 290 A. The central magnetic field is 0.39 T when the current of the MgB2 magnet is 100 A. In this paper, main magnet for MRI with MgB2 composite superconductor is analysed and proposed, including magnet design, test results, and field uniformity. [ABSTRACT FROM AUTHOR]

HTS materials can be used to develop novel permanent magnet (PM) motor. Based on the experimental and theoretical investigations, it was observed that the multi-impulse magnetization strategy should be selected for the constraints such as the temperature distributions and mechanical strength of the motor. The asymmetrical field distribution of HTS would induce torque ripples and unbalanced force. Proper cares have to be taken to avoid irreversible demagnetization. Resin impregnation and enclosing the rotor in a can/sleeve may provide the rotor enough mechanical strength to enable its high speed applications. [ABSTRACT FROM AUTHOR]

Total AC losses in multi-filamentary, silver-sheathed Bi2Sr2Ca2Cu3Oy (Bi-2223) tape were measured as functions of transport current, applied magnetic field and frequency by electromagnetic and calorimetric methods. Results of both methods agree well with each other. The calorimetric method was employed to investigate the effect of the phase difference between transport current and applied field, Δj on total AC loss. Total loss changes significantly with Δj when applied magnetic field is perpendicular to the surface of the sample. The effect of Δj on total loss in parallel magnetic applied field is smaller. [ABSTRACT FROM AUTHOR]

HTS bulks can be used as flux-focusing elements in reluctance motors. As parts of the primary study, a small prototype reluctance motor was designed and constructed by using HTS YBCO bulks. The performance was analyzed based on magnetic field calculation. An experimental investigation was carded out on the prototype motor. Computed parameters are compared with test measurements, showing good agreement. Compared with the conventional synchronous reluctance motors, higher efficiency and smaller size make these motors very attractive for the applications, such as cryogenic pumps and flywheel drives. [ABSTRACT FROM AUTHOR]