Based on the time-dependent coincidence method, a preliminary experiment has been performed on uranium metal castings with similar quality （about 8-10 kg） and shape （hemispherical shell） in different enrichments u...Based on the time-dependent coincidence method, a preliminary experiment has been performed on uranium metal castings with similar quality （about 8-10 kg） and shape （hemispherical shell） in different enrichments using neutron from Cf fast fission chamber and timing DT accelerator. Groups of related parameters can be obtained by analyzing the features of time-dependent coincidence counts between source-detector and two detectors to charac- terize the fission signal. These parameters have high sensitivity to the enrichment, the sensitivity coefficient （defined as （AR/Am）/f-t） can reach 19.3% per kg of 235U. We can distinguish uranium castings with different enrichments to hold nuclear weapon verification.展开更多
Twisted two-dimensional van der Waals heterostructures provide a fertile ground for tailoring electronic and structural properties.However,their vast configurational space poses challenges for systematic study.Here,we...Twisted two-dimensional van der Waals heterostructures provide a fertile ground for tailoring electronic and structural properties.However,their vast configurational space poses challenges for systematic study.Here,weintroduce SAMBA,an open-source,high-throughput Python workflowthat automates the generation,simulation,and analysis of twisted bilayers.Using the coincidence lattice method,we generate a comprehensive set of over 18,000 quasi-commensurable homo-and heterobilayer structures based on 63 experimentally reported monolayers,and perform DFT simulations on a growing subset.The resulting database includes symmetry,interlayer energetics,band alignment,and charge transfer.A detailed case study on graphene-jacutingaite illustrates the framework’s capabilities.This platform offers a robust foundation for data-driven discovery and the rational design of 2D materials with tunable properties.展开更多
In his paper,we obtain a general theorem concerning the existence of solutions to an m-point boundary value problem for the second-order differential equation with impulses.Moreover,the result can also be applied to s...In his paper,we obtain a general theorem concerning the existence of solutions to an m-point boundary value problem for the second-order differential equation with impulses.Moreover,the result can also be applied to study the usual m-point boundary value problem at resonance without impulses.展开更多
文摘Based on the time-dependent coincidence method, a preliminary experiment has been performed on uranium metal castings with similar quality （about 8-10 kg） and shape （hemispherical shell） in different enrichments using neutron from Cf fast fission chamber and timing DT accelerator. Groups of related parameters can be obtained by analyzing the features of time-dependent coincidence counts between source-detector and two detectors to charac- terize the fission signal. These parameters have high sensitivity to the enrichment, the sensitivity coefficient （defined as （AR/Am）/f-t） can reach 19.3% per kg of 235U. We can distinguish uranium castings with different enrichments to hold nuclear weapon verification.
基金support from the Brazilian agencies FAPESP (grants 23/12336-5, 23/09820-2 and FAPESP-CEPID 24/00989-7)CNPq (INCT - Materials Informatics) grant 157793/2025-7, and LNCC (Laboratório Nacional de Computação Científica) for computer time (Project didmat).
文摘Twisted two-dimensional van der Waals heterostructures provide a fertile ground for tailoring electronic and structural properties.However,their vast configurational space poses challenges for systematic study.Here,weintroduce SAMBA,an open-source,high-throughput Python workflowthat automates the generation,simulation,and analysis of twisted bilayers.Using the coincidence lattice method,we generate a comprehensive set of over 18,000 quasi-commensurable homo-and heterobilayer structures based on 63 experimentally reported monolayers,and perform DFT simulations on a growing subset.The resulting database includes symmetry,interlayer energetics,band alignment,and charge transfer.A detailed case study on graphene-jacutingaite illustrates the framework’s capabilities.This platform offers a robust foundation for data-driven discovery and the rational design of 2D materials with tunable properties.
基金Sponsored by the National Natural Science Foundation of China(No.10971238)
文摘In his paper,we obtain a general theorem concerning the existence of solutions to an m-point boundary value problem for the second-order differential equation with impulses.Moreover,the result can also be applied to study the usual m-point boundary value problem at resonance without impulses.
