This study performed a statistical analysis of the correlation and uncertainty of parameters in the classical liquid drop mass formula(namely BW3 type)via regression,along with the theoretical impact of error propagat...This study performed a statistical analysis of the correlation and uncertainty of parameters in the classical liquid drop mass formula(namely BW3 type)via regression,along with the theoretical impact of error propagation.Within the improved BW3 formula,the total deviation between evaluation and experiment can be reduced to 1.66 MeV,involving a reduction from 2.89(2.42)MeV to 1.92(1.89)MeV in the proton(neutron)-dripline region.Ridge regression validation verified this total deviation as the optimal point in the present mass model.Through trend coefficients and Pearson linear-correlation analysis,obvious collinearity was identified between volume,surface,Coulomb,and curvature terms,with notable correlation among high-order symmetry energy and surface symmetry terms.The theoretical derivation of the distribution of binding energy error was then achieved through error propagation analysis.Across the nuclide chart,the error uncertainty of mass predictions varies from 1.996 to 124.469 keV,demonstrating a convex trend of the initial decrease of evaluation error followed by an increase versus the neutron number.展开更多
Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi‐2212)superconducting round wires exhibited great potential for use in high‐field applications.The purity of the precursor powders is critical for the transport current of the wires.Ho...Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi‐2212)superconducting round wires exhibited great potential for use in high‐field applications.The purity of the precursor powders is critical for the transport current of the wires.However,the role of the residual secondary phase in the precursor powders is not fully understood.Here,the origin of the secondary phase was investigated in precursor powders that were prepared using ultrasonic spray pyrolysis(USP)and calcination processing.The microstructure and phase evolution of the precursor powders during the crystallization process were analyzed.Moreover,the effects that the residual secondary phase has on melting behavior,morphology properties,and the supercurrent flow of Bi‐2212 multi‐filamentary wires are systematically discussed.The residual secondary phase in the filament caused further crystallization,and this led to the formation of more and larger Bi‐2201 grains at the onset of the melting process.The poor microstructure and low critical current of the final Bi‐2212 wires can be attributed to the presence of the residual copper‐rich phase.Bi‐2212 wires that were prepared with fully crystallized powders had a high critical current density(J_(c))of 6773 A/mm^(2) at 4.2 K,self‐field.It was revealed that control of the secondary phases in precursor powders is greatly significant for achieving superior values of J_(c).展开更多
基金Research at ZSTU was supported by the National Natural Science Foundation of China(Grants No.U2267205,No.12475124)ZSTU intramural grant(22062267-Y)+2 种基金supported by the National Natural Science Foundation of China(Grant No.12075121)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190067)the Fundamental Research Funds for the Central Universities(Grant No.30922010312)。
文摘This study performed a statistical analysis of the correlation and uncertainty of parameters in the classical liquid drop mass formula(namely BW3 type)via regression,along with the theoretical impact of error propagation.Within the improved BW3 formula,the total deviation between evaluation and experiment can be reduced to 1.66 MeV,involving a reduction from 2.89(2.42)MeV to 1.92(1.89)MeV in the proton(neutron)-dripline region.Ridge regression validation verified this total deviation as the optimal point in the present mass model.Through trend coefficients and Pearson linear-correlation analysis,obvious collinearity was identified between volume,surface,Coulomb,and curvature terms,with notable correlation among high-order symmetry energy and surface symmetry terms.The theoretical derivation of the distribution of binding energy error was then achieved through error propagation analysis.Across the nuclide chart,the error uncertainty of mass predictions varies from 1.996 to 124.469 keV,demonstrating a convex trend of the initial decrease of evaluation error followed by an increase versus the neutron number.
基金supported by the National Key R&D Program of China(2021YFB3800201)the National Science Fund Program of China(No.51777172,51902267)the Natural Science Basic Research Plan in Shaanxi Province(No.2022GY‐392,2021JQ‐884).
文摘Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi‐2212)superconducting round wires exhibited great potential for use in high‐field applications.The purity of the precursor powders is critical for the transport current of the wires.However,the role of the residual secondary phase in the precursor powders is not fully understood.Here,the origin of the secondary phase was investigated in precursor powders that were prepared using ultrasonic spray pyrolysis(USP)and calcination processing.The microstructure and phase evolution of the precursor powders during the crystallization process were analyzed.Moreover,the effects that the residual secondary phase has on melting behavior,morphology properties,and the supercurrent flow of Bi‐2212 multi‐filamentary wires are systematically discussed.The residual secondary phase in the filament caused further crystallization,and this led to the formation of more and larger Bi‐2201 grains at the onset of the melting process.The poor microstructure and low critical current of the final Bi‐2212 wires can be attributed to the presence of the residual copper‐rich phase.Bi‐2212 wires that were prepared with fully crystallized powders had a high critical current density(J_(c))of 6773 A/mm^(2) at 4.2 K,self‐field.It was revealed that control of the secondary phases in precursor powders is greatly significant for achieving superior values of J_(c).
