The corrosive experiments of YBCO were conducted in the steam at different temperatures. The relationship between the critical current and the corrosive time at the same temperature was measured. The corrosion rate wa...The corrosive experiments of YBCO were conducted in the steam at different temperatures. The relationship between the critical current and the corrosive time at the same temperature was measured. The corrosion rate was also calculated. The textured YBCO superconductor was coated by sintering Ag plating method. Another coating method with polytetrafluoroethylene (PTFE) and low temperature resin was studied for the sintered YBCO superconductors as the protect layer. The above two kinds of coating methods can be used to meet the desire of the protection for YBCO superconductor and its thin film device.展开更多
A dream or interesting problem is to obtain more information based on one measurement,for example to obtain all the thermodynamic functions based on specific heat only. We call it"holographic"study.After mor...A dream or interesting problem is to obtain more information based on one measurement,for example to obtain all the thermodynamic functions based on specific heat only. We call it"holographic"study.After more than 10 year's efforts,we suggest one possibility(or only one)is to solve an inverse problem(specific heat-phonon spectrum inversion,SPI).In this talk we will review recent development of studies of a class of inverse problems,including Dai's exact solution and Chen's formula and their unification.T...展开更多
The fabrication of large bulk high temperature superconducting YBCO samples was accomplished by melt-texture-growth(MTG) process with a seeding technique.The microstructure of the samples was observed by a polarizatio...The fabrication of large bulk high temperature superconducting YBCO samples was accomplished by melt-texture-growth(MTG) process with a seeding technique.The microstructure of the samples was observed by a polarization microscope.The observation shows that the samples have controlled orientation and large domains.The magnetic repulsion measurements as a function of distance were carried out.The maximum repulsion between the YBCO sample(29 mm in diameter and 10 mm thick) and a Nd-Fe-B permanent magnet with 0.5T surface magnetic field was 4.8 N/cm2 at 77K.The magnetic levitation on the samples exhibits anisotropic behaviour.展开更多
The top-seeded infiltration and growth process (TSIG) is very effective method for the preparation of YBa2Cu3O7-x (YBCO) bulk superconductors. In order to improve the levitation force of the samples, a series of singl...The top-seeded infiltration and growth process (TSIG) is very effective method for the preparation of YBa2Cu3O7-x (YBCO) bulk superconductors. In order to improve the levitation force of the samples, a series of single domain YBCO bulk superconductors with different ratios of nanoscale Y2Ba4CuBiOy (YBi2411) inclusions in the solid phase pellet is successfully fabricated by the TSIG technique on the basis of previous research. In the present work, the results of YBCO bulk superconductors with YBi2411 and CeO2 (1 wt%) codoping system indicate that, the optimum doping of YBi2411 is 2 wt%, the size of Y211 particles is reduced compared with the samples without CeO2 doping;the largest levitation force is about 15 N obtained in the samples with optimum YBi2411, which is about two times higher than that of the sample without CeO2 doping. The results are very helpful for the fabrication of high quality single domain YBCO bulk superconductors.展开更多
文摘The corrosive experiments of YBCO were conducted in the steam at different temperatures. The relationship between the critical current and the corrosive time at the same temperature was measured. The corrosion rate was also calculated. The textured YBCO superconductor was coated by sintering Ag plating method. Another coating method with polytetrafluoroethylene (PTFE) and low temperature resin was studied for the sintered YBCO superconductors as the protect layer. The above two kinds of coating methods can be used to meet the desire of the protection for YBCO superconductor and its thin film device.
文摘A dream or interesting problem is to obtain more information based on one measurement,for example to obtain all the thermodynamic functions based on specific heat only. We call it"holographic"study.After more than 10 year's efforts,we suggest one possibility(or only one)is to solve an inverse problem(specific heat-phonon spectrum inversion,SPI).In this talk we will review recent development of studies of a class of inverse problems,including Dai's exact solution and Chen's formula and their unification.T...
文摘The fabrication of large bulk high temperature superconducting YBCO samples was accomplished by melt-texture-growth(MTG) process with a seeding technique.The microstructure of the samples was observed by a polarization microscope.The observation shows that the samples have controlled orientation and large domains.The magnetic repulsion measurements as a function of distance were carried out.The maximum repulsion between the YBCO sample(29 mm in diameter and 10 mm thick) and a Nd-Fe-B permanent magnet with 0.5T surface magnetic field was 4.8 N/cm2 at 77K.The magnetic levitation on the samples exhibits anisotropic behaviour.
文摘The top-seeded infiltration and growth process (TSIG) is very effective method for the preparation of YBa2Cu3O7-x (YBCO) bulk superconductors. In order to improve the levitation force of the samples, a series of single domain YBCO bulk superconductors with different ratios of nanoscale Y2Ba4CuBiOy (YBi2411) inclusions in the solid phase pellet is successfully fabricated by the TSIG technique on the basis of previous research. In the present work, the results of YBCO bulk superconductors with YBi2411 and CeO2 (1 wt%) codoping system indicate that, the optimum doping of YBi2411 is 2 wt%, the size of Y211 particles is reduced compared with the samples without CeO2 doping;the largest levitation force is about 15 N obtained in the samples with optimum YBi2411, which is about two times higher than that of the sample without CeO2 doping. The results are very helpful for the fabrication of high quality single domain YBCO bulk superconductors.
