The effect of mold hardness on the microstructure of ductile iron and the contraction porosity was investigated.Molds with different hardnesses（0.41,0.48,0.55,0.62 MPa）and a sand mold prepared by Co2 method were use...The effect of mold hardness on the microstructure of ductile iron and the contraction porosity was investigated.Molds with different hardnesses（0.41,0.48,0.55,0.62 MPa）and a sand mold prepared by Co2 method were used.The influence of silicon content on the induced expansion pressure owing to the formation of graphite was also investigated.The contraction during solidification can be compensated by an induced expansion owing to the graphite relief when the hardness of mold increases;therefore,the possibility of achieving a sound product without using any riser increases.展开更多
The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms o...The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms of symmetry energy. It is found that the neutron-rich system has smaller threshold energy of radial flow and this quantity depends on the form of symmetry potential. It is indicated that the threshold energy of radial flow can provide a new method to determine the symmetry energy of asymmetric nuclear matter.展开更多
文摘The effect of mold hardness on the microstructure of ductile iron and the contraction porosity was investigated.Molds with different hardnesses（0.41,0.48,0.55,0.62 MPa）and a sand mold prepared by Co2 method were used.The influence of silicon content on the induced expansion pressure owing to the formation of graphite was also investigated.The contraction during solidification can be compensated by an induced expansion owing to the graphite relief when the hardness of mold increases;therefore,the possibility of achieving a sound product without using any riser increases.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10575012 and 10435020, the Science Foundation of Beljlng, and the Science Foundation of Beijing Normal University.
文摘The threshold energies of radial flow in reactions of ^40 Ca-^40Ca and ^48Ca＋ ^48Ca in central collisions are investigated within an isospin dependent quantum molecular dynamics model by using three different forms of symmetry energy. It is found that the neutron-rich system has smaller threshold energy of radial flow and this quantity depends on the form of symmetry potential. It is indicated that the threshold energy of radial flow can provide a new method to determine the symmetry energy of asymmetric nuclear matter.
