Ben Ali, NaimTrabelsi, YoussefAlsaif, HaithamBadawi, Issam...
7页查看更多>>摘要：Using the transfer matrix method and Fibonacci structure, an omnidirectional high reflector that covers the fiber optics wavelengths is searched. We aim to make the reflector covers the operating wavelengths of Plastic and Glass fiber optics (650, 850, 1300 and 1550nm). Firstly, an ordinary Fibonacci structure composed of TiO2 and SiO2 slabs materials was studied and for TE and TM polarization modes the reflectance spectra cover only the 850, 1300 and 1550 nm wavelengths and for a limited range of wave-angle of incidence. Secondly, the SiO2 slabs were replaced with the superconductor YBCO slabs which allows the extension of the reflectance bands to cover all fiber optics wavelengths for the entire angle of incidence interval [0-1.5 radian] and for both polarization modes. During that, the structure thickness was optimized by varying the iteration number and the optical thickness of Fibonacci sequence. Finally, the optical behavior of the reflector was tested when changing the ambient temperature.
原文链接:
NSTL
Elsevier
Ikebe, Y.Awaji, S.Ban, E.
6页查看更多>>摘要：In this work, the effect of cobalt (Co) doping on the superconducting properties of filamentary (Sm1/3Gd1/3Dy1/3)(1.18)Ba2.12Cu3.09-xCoxOy (SGD123, x = 0 -1.20) superconductors was investigated using samples prepared using a solution spinning method. Its pinning mechanism was also examined. The Co-doped x = 5.0 x 10(-4) and 1.0 x 10(-3) samples obtained a J(c) value higher than that of the pure sample, although the T-c value of the SGD123 filaments slightly decreased with increasing Co content. The anisotropic behavior of the field dependence of the transport J(c) can hardly be confirmed for the pure sample. The superconductivity of the pure sample disappeared at an applied magnetic field approximately 12 T, at most. In contrast, Co-doped x = 1.0 x 10(-3) sample showed the angular dependence of the transport J(c) in an applied magnetic field. Furthermore, the Co-doped x = 1.0 x 10(-3) sample rotated at 90 degrees maintained a J(c) value higher than 10(3) A cm(-2) in a magnetic field up to 17.5 T. Co doping was effective in enhancing J(c) at self-field and high magnetic field. In addition, we attempted to elucidate the pinning mechanism of Co on the J(c) enhancement of the SGD123 filament using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy measurements.
原文链接:- NSTL
- Elsevier
Xu, YingWu, XiaochenHu, ZihengZhang, Bin...
6页查看更多>>摘要：High-temperature superconducting (HTS) direct current (DC) cables have advantages of large capacity, low transmission loss, and small size over conventional cables under normal operating conditions, which give a promising potential to upgrade the power grid. However, under fault current, which is 10-30 times larger than the rated current, the quench and the subsequent heat generation of HTS tapes pose a great challenge to the thermal stability of the HTS cable stability. Therefore, it is important to study the quench behaviors, recovery characteristics, and thermal stability criteria of HTS cables. In this paper, we studied the transient thermal stability of the superconducting cable through theoretical analysis and experimental verification. The influence of the thickness and the structure of the insulation layer, and parallel connected stabilizing layers are considered. The results show that the thickness and structure of the insulation layer affect the heat transfer efficiency between HTS tapes and liquid nitrogen thus affecting the thermal stability criteria, and the parallel connected stabilizing layer has a current shunt effect and contributes to the heat capacity so that stabilized the cable against thermal impulse.
原文链接:- NSTL
- Elsevier
Chen, DachuanLi, Xiao-FenWu, WeiSheng, Jie...
6页查看更多>>摘要：Magnetic levitation (Maglev) train has the advantages of high speed, low noise, low carbon emission and low operation costs, which meets the demands of future transportation systems. The high temperature super-conducting (HTS) ElectroDynamic Suspension (EDS) system with on board HTS magnets and null-flux ground suspension coils is one of the most promising schemes for commercial operation. The numerical model of the electromagnetic forces in the HTS EDS system is well established through the dynamic circuit approach. However some realistic behavior including the eddy current induced in the metal vessel cannot be easily described as simple circuit components like a coil. The analysis of these issues is easier with a finite element method (FEM). In this paper, a three-dimensional FEM model is built to simulate the electromagnetic behavior of the null-flux coils - HTS magnet mechanism in motion. Especially, the electromagnetic interaction forces between the ground null-flux coils and HTS magnets mechanism are studied. Moreover, effects of framed vessel structures on electro-magnetic forces of the HTS EDS system is discussed.
原文链接:- NSTL
- Elsevier
