To study the influence of thickness on the magnetic properties of ReBCO(Re = Y, Gd, Sm, Nd, etc.) bulk superconductors, a single domain gadolinium barium copper oxide(GdBCO) bulk superconductor fabricated by the Re + ...To study the influence of thickness on the magnetic properties of ReBCO(Re = Y, Gd, Sm, Nd, etc.) bulk superconductors, a single domain gadolinium barium copper oxide(GdBCO) bulk superconductor fabricated by the Re + 011 top seeded infiltration growth(Re + 011 TSIG) method was continuously sliced along the bottom to obtain samples of different thickness. The levitation force and attractive force of these samples were tested at 77 K in the zero-field-cooled(ZFC)state. It is found that as the sample thickness decreases, the levitation force decreases gradually whereas the attractive force increases. This is related to the varied ability to resist the penetration of magnetic field occasioned by varying sample thickness, which are deeply revealed by combining with the characteristics of the non-ideal type-II superconductor. Further,the levitation force exhibits a trend of slow initial change followed by rapid change, which may be attributed to the growth of the sample. Measurement of the trapped field shows that a similar distribution of trapped field at the top and bottom surfaces can be achieved by removing some materials from the bottom of the bulk. These results provide a reference for meeting the actual requirements of ReBCO bulks of different thicknesses and greatly contribute to practical designs and applications.展开更多
The goal of the present study was to investigate the influence of latex particle aggregation on membrane fouling attachments and the ultrafiltration performance of simulated latex effluent using Cetyltrimethyl Ammoniu...The goal of the present study was to investigate the influence of latex particle aggregation on membrane fouling attachments and the ultrafiltration performance of simulated latex effluent using Cetyltrimethyl Ammonium Bromide（CTAB） as a cationic surfactant. Hydrophilic polysulfone and ultrafilic flat heterogeneous membranes, with molecular weight cut off（MWCO） of 60,000 and 100,000, respectively, as well as hydrophobic polyvinylidene difluoride with MWCO of 100,000, were used under a constant flow rate and cross-flow mode in ultrafiltration of latex solution. In addition, a polycarbonate flat membrane with uniform pore size of 0.05 μm was likewise used during the experiment. The effects of CTAB on the latex particle size distribution were investigated at various concentrations, different treatment times, and diverse agitation duration times. The effects of CTAB on the zeta potential of membrane surfaces and latex particles were also investigated. The data obtained indicate that the particle size distribution of treated latex effluent experienced significant shifts in the peaks toward a larger size range caused by the aggregation of particles. As a result, the mass of fouling contributing to pore blocking and the irreversible fouling were noticeably reduced. The optimum results occurred in the instance when CTAB was added at the critical micelle concentration of 0.36 g/L, for the duration of 10 min and with minimal agitation. Notably, a higher stirring rate had an overall negative effect on the membrane fouling minimization.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 52072229)the Key-grant Project of the Ministry of Education of China (Grant No. 311033)+1 种基金the Fundamental Research Funds for the Central Universities (Grant No. GK201706001)the Teaching Reform and Innovation Project of Higher Education in Shanxi Province, China (Grant No. J2021719)。
文摘To study the influence of thickness on the magnetic properties of ReBCO(Re = Y, Gd, Sm, Nd, etc.) bulk superconductors, a single domain gadolinium barium copper oxide(GdBCO) bulk superconductor fabricated by the Re + 011 top seeded infiltration growth(Re + 011 TSIG) method was continuously sliced along the bottom to obtain samples of different thickness. The levitation force and attractive force of these samples were tested at 77 K in the zero-field-cooled(ZFC)state. It is found that as the sample thickness decreases, the levitation force decreases gradually whereas the attractive force increases. This is related to the varied ability to resist the penetration of magnetic field occasioned by varying sample thickness, which are deeply revealed by combining with the characteristics of the non-ideal type-II superconductor. Further,the levitation force exhibits a trend of slow initial change followed by rapid change, which may be attributed to the growth of the sample. Measurement of the trapped field shows that a similar distribution of trapped field at the top and bottom surfaces can be achieved by removing some materials from the bottom of the bulk. These results provide a reference for meeting the actual requirements of ReBCO bulks of different thicknesses and greatly contribute to practical designs and applications.
基金support from Natural Science and Engineering Research Council of Canada(NSERC)(RGPIN/216939-2013)The assistance and facilities provided by the Department of Chemical Engineering,Ryerson University
文摘The goal of the present study was to investigate the influence of latex particle aggregation on membrane fouling attachments and the ultrafiltration performance of simulated latex effluent using Cetyltrimethyl Ammonium Bromide（CTAB） as a cationic surfactant. Hydrophilic polysulfone and ultrafilic flat heterogeneous membranes, with molecular weight cut off（MWCO） of 60,000 and 100,000, respectively, as well as hydrophobic polyvinylidene difluoride with MWCO of 100,000, were used under a constant flow rate and cross-flow mode in ultrafiltration of latex solution. In addition, a polycarbonate flat membrane with uniform pore size of 0.05 μm was likewise used during the experiment. The effects of CTAB on the latex particle size distribution were investigated at various concentrations, different treatment times, and diverse agitation duration times. The effects of CTAB on the zeta potential of membrane surfaces and latex particles were also investigated. The data obtained indicate that the particle size distribution of treated latex effluent experienced significant shifts in the peaks toward a larger size range caused by the aggregation of particles. As a result, the mass of fouling contributing to pore blocking and the irreversible fouling were noticeably reduced. The optimum results occurred in the instance when CTAB was added at the critical micelle concentration of 0.36 g/L, for the duration of 10 min and with minimal agitation. Notably, a higher stirring rate had an overall negative effect on the membrane fouling minimization.
