The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different...The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different from that of ordinary regions in synchrotron topographs.Differential thermal analysis indiates that the Curie temperature of the extraordinary region is lower than that of ordinary region,and the extraordinary region is really a high defect density region.The diffraction contrast of the extraordinary region in synchrotron topographs is explained qualitatively by a calculation at the selected wavelength.2001 Published by Elsevier Science B.V.展开更多
For the development of high‐temperature superconducting(HTS)magnet systems of future fusion devices,a novel HTS round strand based on a stacking structure was designed and manufactured using second generation(2G)HTS ...For the development of high‐temperature superconducting(HTS)magnet systems of future fusion devices,a novel HTS round strand based on a stacking structure was designed and manufactured using second generation(2G)HTS tapes.Different mechanical loads during operation can result in irreversible degradation of the strand.The axial tension and fatigue loads need particular attention.Therefore,it is important to investigate the electromechanical behavior of the round strand under various axial tension and cyclic loads.In this paper,the axial tensile and fatigue tests were conducted at 77 K,self‐field.Taking 95%critical current(I_(c))retention as the criterion,the results of the tensile tests revealed that the average tensile stress and strain were as high as 344 MPa and 0.47%,respectively.Fatigue characteristics were also investigated as a function of axial tensile stress.No significant performance degradation was observed up to 100,000 loading cycles with stress amplitudes ranging from 20 MPa to 200 MPa.Ic degradation occurs after 16,000 loading cycles with 380 MPa as the maximum stress.Furthermore,the microscopic defects of the round strand samples due to fabrication imperfections and mechanical loading were investigated using metallographic microscope and scanning electron microscope.These results presented in this paper are useful for comprehending and improving the mechanical behaviors of the strand in high‐field and large‐scale fusion magnet systems.展开更多
文摘The inhomogeneity in a congrunet LiTaO3 crystal has been observed by transmission synchrotron topography.Many extraordinary regions exist in congruent LiTaO3 crystal and they often show diffraction intensity different from that of ordinary regions in synchrotron topographs.Differential thermal analysis indiates that the Curie temperature of the extraordinary region is lower than that of ordinary region,and the extraordinary region is really a high defect density region.The diffraction contrast of the extraordinary region in synchrotron topographs is explained qualitatively by a calculation at the selected wavelength.2001 Published by Elsevier Science B.V.
基金supported by the Southwestern Institute of Physics(SWIP)under project number 202101XWCXRZ001 and 2021XWCXRZ002.
文摘For the development of high‐temperature superconducting(HTS)magnet systems of future fusion devices,a novel HTS round strand based on a stacking structure was designed and manufactured using second generation(2G)HTS tapes.Different mechanical loads during operation can result in irreversible degradation of the strand.The axial tension and fatigue loads need particular attention.Therefore,it is important to investigate the electromechanical behavior of the round strand under various axial tension and cyclic loads.In this paper,the axial tensile and fatigue tests were conducted at 77 K,self‐field.Taking 95%critical current(I_(c))retention as the criterion,the results of the tensile tests revealed that the average tensile stress and strain were as high as 344 MPa and 0.47%,respectively.Fatigue characteristics were also investigated as a function of axial tensile stress.No significant performance degradation was observed up to 100,000 loading cycles with stress amplitudes ranging from 20 MPa to 200 MPa.Ic degradation occurs after 16,000 loading cycles with 380 MPa as the maximum stress.Furthermore,the microscopic defects of the round strand samples due to fabrication imperfections and mechanical loading were investigated using metallographic microscope and scanning electron microscope.These results presented in this paper are useful for comprehending and improving the mechanical behaviors of the strand in high‐field and large‐scale fusion magnet systems.
