The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bu...The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bulk material,which could be benefited from pulsed neutron source.Here we build a Bragg-edge imaging system on the General Purpose Powder Diffractometer at the China Spallation Neutron Source.The residual strain mapping of a bent Q235 ferrite steel sample has been achieved with a spectral resolution of 0.15%by the time-of-flight neutron Bragg-edge imaging on this system.The results show its great potential applications in materials science and engineering.展开更多
This paper is concerned with a stabilized approach to low-order mixed finite element methods for the Stokes equations.We will provide a posteriori error analysis for the method.We present two a posteriori error indica...This paper is concerned with a stabilized approach to low-order mixed finite element methods for the Stokes equations.We will provide a posteriori error analysis for the method.We present two a posteriori error indicators which will be demonstrated to be globally upper and locally lower bounds for the error of the finite element discretization.Finally two numerical experiments will be carried out to show the efficiency on constructing adaptive meshes.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFB0701903 and 2016YFA0401502)the National Natural Science Foundation of China(Grant No.12041202)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2017023)the Guangdong Natural Science Foundation,China(Grant No.2016A030313129)the Department of Science and Technology of Guangdong Province under grant project of energy-resolved neutron imaging instrument.
文摘The neutron Bragg-edge imaging is expected to be a new non-destructive energy-resolved neutron imaging technique for quantitatively two-dimensional or three-dimensional visualizing crystallographic information in a bulk material,which could be benefited from pulsed neutron source.Here we build a Bragg-edge imaging system on the General Purpose Powder Diffractometer at the China Spallation Neutron Source.The residual strain mapping of a bent Q235 ferrite steel sample has been achieved with a spectral resolution of 0.15%by the time-of-flight neutron Bragg-edge imaging on this system.The results show its great potential applications in materials science and engineering.
基金supported by the NSF of China(No.10971166)the National Basic Research Program(No.2005CB321703).
文摘This paper is concerned with a stabilized approach to low-order mixed finite element methods for the Stokes equations.We will provide a posteriori error analysis for the method.We present two a posteriori error indicators which will be demonstrated to be globally upper and locally lower bounds for the error of the finite element discretization.Finally two numerical experiments will be carried out to show the efficiency on constructing adaptive meshes.
