The neutron-induced total cross sections of natural lead have been measured in a wide energy range(0.3 eV-20 MeV)on the back-streaming white neutron beamline(Back-n)at the China Spallation Neutron Source.Neutron energ...The neutron-induced total cross sections of natural lead have been measured in a wide energy range(0.3 eV-20 MeV)on the back-streaming white neutron beamline(Back-n)at the China Spallation Neutron Source.Neutron energy was determined by the neutron total cross-section spectrometer using the time-of-flight technique.A fast multi-cell fission chamber was used as the neutron detector,and a 10-mm-thick high-purity natural lead sample was employed for the neutron transmission measurements.The on-beam background was determined using Co,In,Ag,and Cd filters.The excitation function of ^(nat)Pb(n,tot)reaction below 20 MeV was calculated using the TALYS-1.96 nuclear-reaction modeling program.The present results were compared with previous results,the evaluated data available in the five major evaluated nuclear data libraries(i.e.,ENDF/B-VIII.0,JEFF-3.3,JENDL-5,CENDL-3.2,and BROND-3.1),and the theoretical calculation curve.Good agreement was found between the new results and those of previous experiments and with the theoretical curves in the corresponding region.This measurement obtained the neutron total cross section of natural lead with good accuracy over a wide energy range and added experimental data in the resonance energy range.This provides more reliable experimental data for nuclear engineering design and nuclear data evaluation of lead.展开更多
In this study,measurements of the^(128)Te(n,2n)^(127m,g)Te reaction cross sections and the computation of the isomeric cross section ratio were performed around the neutron energy of 13−15 MeV.We used aγ-ray spectrom...In this study,measurements of the^(128)Te(n,2n)^(127m,g)Te reaction cross sections and the computation of the isomeric cross section ratio were performed around the neutron energy of 13−15 MeV.We used aγ-ray spectrometric technique to conduct the measurements.The neutron energy was produced by the^(3)H(d,n)^(4)He reaction.For the^(128)Te(n,2n)^(127m,g)Te reaction,the excited state,ground state,total cross section,and isomeric cross section ratio were determined using the TALYS-1.96 code,a theoretical nuclear model that allows for variations in density options.The initial experimental data,assessed nuclear data,and theoretical calculations based on the TALYS-1.96 algorithm were compared with the measurement results.The new data produced by this study are essential for validating nuclear models and establishing parameters for nuclear reactions.展开更多
Defect and interface engineering have been recognized as efficient strategies for developing high-performance electrocatalysts.However,it is still challenging to couple defect and interface engineering in transition m...Defect and interface engineering have been recognized as efficient strategies for developing high-performance electrocatalysts.However,it is still challenging to couple defect and interface engineering in transition metal sulfides and understand their dynamic evolution process during electrocatalysis.Herein,we developed one-step pyrolysis of bimetallic sulfide to construct S vacancy-rich Cu_(1.96)S/Co_(9)S_(8) heterostructure by controlling the critical decomposition temperature.The as-synthesized Cu_(1.96)S/Co_(9)S_(8) exhibits excellent bifunctional electrocatalytic performance,with a low overpotential of 99 and 200 mV at 10 mA cm−2 towards hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in 1.0 mol/L KOH electrolyte,respectively.A symmetric two-electrode cell with Cu_(1.96)S/Co_(9)S_(8) delivered a current density of 10 mA cm^(−2) at a low voltage of 1.43 V and showed long-term stability for 200 h.A series of in/ex-situ techniques revealed that the electrochemical reconfiguration only appeared in the OER process,resulting in the CoOOH/CuO and SO42−species promoting OER performance.Meanwhile,the S vacancy and heterostructure interface in Cu_(1.96)S/Co_(9)S_(8) were proved to optimize the electronic structure and the adsorption of intermediates for HER by density function theory(DFT)simulations.This work provides a promising strategy to construct metal sulfides with rich defects and heterogeneous interfaces and understand their dynamic evolution process for electrochemical storage and conversion devices.展开更多
基金This work is supported by the National Natural Science Foundation of China(No.12375296)the Key Laboratory of Nuclear Data Foundation(No.JCKY2022201C153)+2 种基金the Natural Science Foundation of Hunan Province of China(Nos.2021JJ40444,2020RC3054)the Youth Innovation Promotion Association CAS(No.2023014)the National Key Research and Development Plan(No.2022YFA1603303).
文摘The neutron-induced total cross sections of natural lead have been measured in a wide energy range(0.3 eV-20 MeV)on the back-streaming white neutron beamline(Back-n)at the China Spallation Neutron Source.Neutron energy was determined by the neutron total cross-section spectrometer using the time-of-flight technique.A fast multi-cell fission chamber was used as the neutron detector,and a 10-mm-thick high-purity natural lead sample was employed for the neutron transmission measurements.The on-beam background was determined using Co,In,Ag,and Cd filters.The excitation function of ^(nat)Pb(n,tot)reaction below 20 MeV was calculated using the TALYS-1.96 nuclear-reaction modeling program.The present results were compared with previous results,the evaluated data available in the five major evaluated nuclear data libraries(i.e.,ENDF/B-VIII.0,JEFF-3.3,JENDL-5,CENDL-3.2,and BROND-3.1),and the theoretical calculation curve.Good agreement was found between the new results and those of previous experiments and with the theoretical curves in the corresponding region.This measurement obtained the neutron total cross section of natural lead with good accuracy over a wide energy range and added experimental data in the resonance energy range.This provides more reliable experimental data for nuclear engineering design and nuclear data evaluation of lead.
基金Supported by the National Natural Science Foundation of China(12165006,12375295)。
文摘In this study,measurements of the^(128)Te(n,2n)^(127m,g)Te reaction cross sections and the computation of the isomeric cross section ratio were performed around the neutron energy of 13−15 MeV.We used aγ-ray spectrometric technique to conduct the measurements.The neutron energy was produced by the^(3)H(d,n)^(4)He reaction.For the^(128)Te(n,2n)^(127m,g)Te reaction,the excited state,ground state,total cross section,and isomeric cross section ratio were determined using the TALYS-1.96 code,a theoretical nuclear model that allows for variations in density options.The initial experimental data,assessed nuclear data,and theoretical calculations based on the TALYS-1.96 algorithm were compared with the measurement results.The new data produced by this study are essential for validating nuclear models and establishing parameters for nuclear reactions.
基金supported by the National Natural Science Foundation of China(Nos.U1904190 and22202065)the Natural Science Foundation for Excellent Young Scholars of Henan Province(No.212300410091)+1 种基金the Program for Science and Tech-nology Innovation Talents in Universities of Henan Province(No.22HASTIT005)the Key Program of Henan Province for Science and Technology(No.222102240029).
文摘Defect and interface engineering have been recognized as efficient strategies for developing high-performance electrocatalysts.However,it is still challenging to couple defect and interface engineering in transition metal sulfides and understand their dynamic evolution process during electrocatalysis.Herein,we developed one-step pyrolysis of bimetallic sulfide to construct S vacancy-rich Cu_(1.96)S/Co_(9)S_(8) heterostructure by controlling the critical decomposition temperature.The as-synthesized Cu_(1.96)S/Co_(9)S_(8) exhibits excellent bifunctional electrocatalytic performance,with a low overpotential of 99 and 200 mV at 10 mA cm−2 towards hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in 1.0 mol/L KOH electrolyte,respectively.A symmetric two-electrode cell with Cu_(1.96)S/Co_(9)S_(8) delivered a current density of 10 mA cm^(−2) at a low voltage of 1.43 V and showed long-term stability for 200 h.A series of in/ex-situ techniques revealed that the electrochemical reconfiguration only appeared in the OER process,resulting in the CoOOH/CuO and SO42−species promoting OER performance.Meanwhile,the S vacancy and heterostructure interface in Cu_(1.96)S/Co_(9)S_(8) were proved to optimize the electronic structure and the adsorption of intermediates for HER by density function theory(DFT)simulations.This work provides a promising strategy to construct metal sulfides with rich defects and heterogeneous interfaces and understand their dynamic evolution process for electrochemical storage and conversion devices.
