Two linked models have been developed to explore the relationship between the amount of porosity arising in service from both radiolytic oxidation and fast neutron damage that influences both the strength and the forc...Two linked models have been developed to explore the relationship between the amount of porosity arising in service from both radiolytic oxidation and fast neutron damage that influences both the strength and the force-displacement(load-displacement)behaviour and crack propagation in pile grade A graphite used as a nuclear reactor moderator material.Firstly models of the microstructure of the porous graphite for both unirradiated and irradiated graphite are created.These form the input for the second stage,simulating fracture in lattice-type finite element models,which predicts force(load)-displacement and crack propagation paths.Microstructures comprising aligned filler particles,typical of needle coke,in a porous matrix have been explored.The purpose was to isolate the contributions of filler particles and porosity to fracture strength and crack paths and consider their implications for the overall failure of reactor core graphite.展开更多
We are now preparing for the third generation (e,e' K+) Λ hypernuclear spectroscopic experiment at Hall C,Jefferson Lab (USA). The goal of the experiment is the precise spectroscopy of hypernuclei in wide mass re...We are now preparing for the third generation (e,e' K+) Λ hypernuclear spectroscopic experiment at Hall C,Jefferson Lab (USA). The goal of the experiment is the precise spectroscopy of hypernuclei in wide mass region. We have constructed a new high resolution electron spectrometer "HES" dedicated to (e,e' K+) hypernuclear study in Japan and it was shipped to JLab in February,2008. We will discuss about the physics of the (e,e' K+) hypernuclear study at JLab and report the current preparation status of the third generatrion experiment.展开更多
文摘Two linked models have been developed to explore the relationship between the amount of porosity arising in service from both radiolytic oxidation and fast neutron damage that influences both the strength and the force-displacement(load-displacement)behaviour and crack propagation in pile grade A graphite used as a nuclear reactor moderator material.Firstly models of the microstructure of the porous graphite for both unirradiated and irradiated graphite are created.These form the input for the second stage,simulating fracture in lattice-type finite element models,which predicts force(load)-displacement and crack propagation paths.Microstructures comprising aligned filler particles,typical of needle coke,in a porous matrix have been explored.The purpose was to isolate the contributions of filler particles and porosity to fracture strength and crack paths and consider their implications for the overall failure of reactor core graphite.
文摘We are now preparing for the third generation (e,e' K+) Λ hypernuclear spectroscopic experiment at Hall C,Jefferson Lab (USA). The goal of the experiment is the precise spectroscopy of hypernuclei in wide mass region. We have constructed a new high resolution electron spectrometer "HES" dedicated to (e,e' K+) hypernuclear study in Japan and it was shipped to JLab in February,2008. We will discuss about the physics of the (e,e' K+) hypernuclear study at JLab and report the current preparation status of the third generatrion experiment.
