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ABSTRACT We report a novel superconductivity fault current limiters (SFCLs) using high-temperature superconducting (HTS) materials, which serve as the protection devices in high-speed communication systems. Although the superconductivity-material YBaCuO has been regarded as a candidate for FCL owing to its attractive characteristics of good thermal stability and fast quenching capability, there is still no adequate limiter design with good impedence matching and high RF-circuit integration for communication system. Here, we proposed a new structure of FCL, and the new FCL is called mixed-line FCL, featuring a cost-effective monocoque design without integrated passive components, which not only simplify the circuit design and process complexity in conventional power system with FCL, but also lower generated joule energy during operation because of fast nanosecond-level switching. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:964-966, 2017 [ABSTRACT FROM AUTHOR]

Abstract: An overview of the recent development of the superconducting FeSe1− x and related compounds is presented. Methods to synthesize high purity polycrystalline samples, single crystals and thin films with preferred orientation are described. In addition to the synthesis of FeSe and FeSeTe, the effects of various partial chemical substitutions on Fe and Se/Te site are described. It was found that the effects of chemical doping to the Se-site or Fe-site are rather different. Ionic size of the dopant is found to play a critical role on the occurrence of superconductivity. We also review the physical properties, including transport, magnetic, and thermal properties. There exist interesting transport anomalies in the resistivity at low temperature, and it was found that a structural distortion at low temperature is critical to the occurrence of superconductivity in these materials. However, the exact origin of these observed anomalies is not clear, and the exact pairing symmetry in FeSe-based superconductors is also still in question. [Copyright &y& Elsevier]

Abstract: Crystals of the new superconductor FeSe were investigated by X-ray absorption near edge structures spectroscopy (XANES) in the temperature range 300–77K. Crystals with Se content varying from x=1–0.8 were used. The Fe K-edge spectra show a structure distortion and increase in hole content as x decreases. The Fe K-edge spectra also show changes when the crystals are cooled to 100K which may be related to the orthorhombic distortion reported in these crystals. The data is examined in conjunction with XRD measurements on the crystals to seek a correlation. [Copyright &y& Elsevier]