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Otsuka A.,Kobe University | Otsuka A.,Japan Superconductor Technology Inc. | Kiyoshi T.,Japan National Institute of Materials Science | Takeda M.,Kobe University
IEEE Transactions on Applied Superconductivity

NMR magnets using high-T c superconductors (HTS) to generate high magnetic fields exceeding 25 T are currently being designed by several organizations. In these designs, the HTS is used for the inner coils, and the other coils consist of NbTi and Nb 3Sn wires. The YBCO wire, which is a typical HTS, has excellent critical current performance over a wide range of magnetic fields and tolerates high tensile stress of up to 700 MPa. These properties make it possible to realize a high-field NMR magnet. In particular, the superior mechanical strength allows for the high-stress criterion of the electromagnetic force to be applied to the design of the magnets. In this study, we show the conceptual design of 1.3 GHz (30.5 T) NMR magnets under the condition of high hoop stress of 500 MPa. To achieve high magnetic field homogeneity in these designs, we propose three magnet design plans that have different arrangements of the compensation coils. We assumed that the magnet would be operated by the driven mode at 4.2 K. We also considered the strong angular dependence of the critical current of the YBCO wires to design the magnet. © 2006 IEEE. Source

Nakamura A.,Tokyo University of Science | Ohtsuka J.,Tokyo University of Science | Miyazono K.-I.,Tokyo University of Science | Yamamura A.,Tokyo University of Science | And 6 more authors.
Crystal Growth and Design

Space-based microgravity environments have been utilized to obtain a highly ordered crystal because of the lack of gravity-induced convection. A superconducting magnet-based quasi-microgravity is also expected to contribute to the enhancement of the quality of protein crystals. We here report a case study on protein crystallization using fifteen kinds of samples in a magnetic field gradient, which was sufficient for magnetic levitation of water droplets. In three cases, rod-type crystals were aligned perpendicular to the crystallization plate, exhibiting magnetic orientation parallel to the direction of the magnetic field. Five proteins showed improvement in crystal quality evaluated by the resolution limit in X-ray diffraction experiments and the overall B-factor of the crystal. Our data support the idea that the reduced-gravity environment produced by a high magnetic field gradient can be used to obtain enhanced-quality protein crystals, aiding in the determination of their precise crystal structures. © 2012 American Chemical Society. Source

Japan Superconductor Technology Inc. and Japan National Institute of Materials Science | Date: 2014-03-07

An object of the present invention is to provide a method for protecting a superconducting coil, which method prevents damage to the superconducting coil caused by a quench or the like, in a new way, without using a voltage (a change in voltage) generated in the superconducting coil. Provided is the method for protecting a superconducting coil made by winding tape-like superconducting wire having a superconducting layer. Power from a power supply is shut off based on the magnitude of a screening field, which is a difference between a measured magnetic field B in a direction of a thickness of the superconducting wire at a predetermined position, and a magnetic field Bcal in the direction of the thickness of the superconducting wire calculated disregarding an effect of screening current.

Japan Superconductor Technology Inc. | Date: 2007-07-10

Electrical conductors, wire for superconductors, magnets for superconductors.

Kiyoshi T.,Japan National Institute of Materials Science | Choi S.,Japan National Institute of Materials Science | Matsumoto S.,Japan National Institute of Materials Science | Zaitsu K.,Kobe Steel | And 5 more authors.
IEEE Transactions on Applied Superconductivity

Because of their high critical fields, high-T c superconductors (HTS) are considered to be the only solution to dramatically increase the highest fields of NMR magnets. We have successfully demonstrated that a 500 MHz HTS/LTS NMR system with a Bi-2223 innermost coil could be used for solution NMR in a driven-mode operation. As the next step, the upgrade of the 920 MHz NMR system installed at the Tsukuba Magnet Laboratory is underway. The innermost Nb 3Sn coil has been replaced by a Bi-2223 coil. The coil was fabricated as a layer-wound coil using five Bi-2223 conductors reinforced with bronze tapes. It was connected in series with the outer Nb 3 Sn and NbTi coils. The magnet is expected to generate a field of 24.2 T (1.03 GHz of 1H resonance frequency) at an operating current of 244.4 A. The test using the Bi-2223 coil and the outer Nb 3Sn coils in combination was successfully carried out. The coil has been installed in the 1.03 GHz NMR magnet. Its cooling and operation are scheduled to take place within Fiscal Year 2010. © 2010 IEEE. Source

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