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Design of YBCO Superconducting Magnets with Highly Homogeneous Magnetic
Fields |
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We study how to design YBCO superconducting magnets producing highly stable
and homogeneous magnetic fields, which are required for NMR and MRI devices.
YBCO superconducting wires have the shape of tapes. Magnetic field perpendicular
to the surface of the wires induces screening currents in the wires. The
currents and magnetic field decay with time and result in generating inhomogeneous
fields. We try to evaluate the screening currents from measurement data
and develop a design method suitable for YBCO wires. |
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Superconducting Motors and Generators |
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We have studied 10 MW-class superconducting wind turbine generators, which
are characterized as a high torque and very low speed machine and expected
to be applied to off-shore wind power generation. Performance analysis
using the three-dimensional finite element method, and conceptual machine
designs have been carried out. Several field magnet designs have been investigated
for a high power density machine, such as a combination of bulk superconductors
and superconducting windings, transverse- flux enhanced type field windings,
and conventional racetrack coils, etc. Cooling systems and mechanical support
structures for them have been also studied. In addition, high power density
motors have been investigated. |
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Superconducting Technology for Railway Systems |
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Application of superconducting technologies to railway systems has been
studied. Design study of high-temperature superconducting magnets for the
maglev system has been carried out. In addition, potential application
of DC superconducting power cable to DC feeding systems in conventional
railway systems, combined with other superconducting equipment and energy
storage devices have been studied based on numerical simulation. |
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Medical Applications of Superconducting Technologies and Electromagnetic
Fields |
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We develop a new magnetic resonance imaging (MRI) technique for visualizing dielectric properties of biological tissues which could not be measured using conventional techniques. The accuracy of the proposed method is evaluated using numerical methods. A dedicated RF coil improves the efficacy of signal acquisition. Another project is to develop a compact transcranial magnetic stimulator for treatment of pain at home. The equipment incorporates a novel coil producing magnetic fields. |
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Electromagnetic Phenomena in Bulk Superconductors and their Applications |
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For practical application of (RE)BCO bulk superconductors, which have high
critical current densities based on strong flux pinning characteristics,
electromagnetic phenomena inside the superconductors have been studied.
For their magnet applications, pulsed-field and field-cooling magnetization
methods have been examined using a FEM analysis tool developed for studying
improvement of magnetization performance. Magnetic shielding application
of bulk superconductor is also investigated. |
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Development of Self-consistent Numerical Analysis Tool for Microwave-exited
Plasma |
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Microwave-excited plasmas can be generated very stably at the low gas pressure, and even at the atmospheric pressure. However, the device characteristics cannot be prospected and optimized on the design level due to the close and complicated coupling of plasma parameters and microwave propagation characteristics. In order to overcome this problem, it needs to simulate them simultaneously. In this study, we develop a self-consistent numerical analysis tool in three-dimensional system with combining plasma fluid model and FDTD (Finite-Difference Time-Domain) method. |
