The eruption of Vesuvius of 79 AD caused extensive destructions all over the Campanian area, engulfing the cities of Pompeii, Herculaneum, Oplonti and Stabiae.The eruption followed a long quiescence period and the i...The eruption of Vesuvius of 79 AD caused extensive destructions all over the Campanian area, engulfing the cities of Pompeii, Herculaneum, Oplonti and Stabiae.The eruption followed a long quiescence period and the inhabitants of the area were surprised by the volcanic events. The first part of the eruption was characterized by a widespread dispersal of pumices from a high erup-tive column. The second part of the eruption, character-ized by pyroclastic flows emplacement, caused the major damages with extensive life losses in most of the towns surrounding the volcano. In Pompeii, the major casual-ties during the first phase resulted from roof collapses;during the second phase, people were killed either by physical trauma due to the kinetic energy of the flow or by suffucation because of the ash-rich atmosphere.展开更多
The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in the framework of the Brueckner–Hartree–Fock theory including a three-body force. The energy per nucleon E<SUB>A<...The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in the framework of the Brueckner–Hartree–Fock theory including a three-body force. The energy per nucleon E<SUB>A</SUB>(δ) calculated in the full range of spin polarization for symmetric nuclear matter and pure neutron matter fulfills a parabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density along with the related quantities such as the magnetic susceptibility and the Landau parameter G<SUB>0</SUB>. The main effect of the three-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value with only two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurations studied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.展开更多
The three-body force effects on the equation of state and its iso-spin dependence of asymmetric nuclear matter and on the proton fraction in neutron star matter have been investigated within Brueckner-Hartree-Fock app...The three-body force effects on the equation of state and its iso-spin dependence of asymmetric nuclear matter and on the proton fraction in neutron star matter have been investigated within Brueckner-Hartree-Fock approach by using a microscopic three-body force. It is shown that, even in the presence of the three-body force, the empirical parabolic law of the energy per nucleon vs. isospin asymmetry is fulfilled in the whole asymmetry range and also up to high density. The three-body force provides a strong enhancement of symmetry energy at high density in agreement with relativistic approaches. It also shows that the three-body force leads to a much more rapid increasing of symmetry energy with density in relatively high density region and to a much lower threshold density for the direct URCA process to occur in a neutron star as compared to the predictions adopting only pure two-body force.展开更多
文摘The eruption of Vesuvius of 79 AD caused extensive destructions all over the Campanian area, engulfing the cities of Pompeii, Herculaneum, Oplonti and Stabiae.The eruption followed a long quiescence period and the inhabitants of the area were surprised by the volcanic events. The first part of the eruption was characterized by a widespread dispersal of pumices from a high erup-tive column. The second part of the eruption, character-ized by pyroclastic flows emplacement, caused the major damages with extensive life losses in most of the towns surrounding the volcano. In Pompeii, the major casual-ties during the first phase resulted from roof collapses;during the second phase, people were killed either by physical trauma due to the kinetic energy of the flow or by suffucation because of the ash-rich atmosphere.
基金中国科学院知识创新工程项目，国家重点基础研究发展计划(973计划)，the Important Pre-research Project，科技部资助项目
文摘The equations of state of spin-polarized nuclear matter and pure neutron matter are studied in the framework of the Brueckner–Hartree–Fock theory including a three-body force. The energy per nucleon E<SUB>A</SUB>(δ) calculated in the full range of spin polarization for symmetric nuclear matter and pure neutron matter fulfills a parabolic law. In both the cases the spin-symmetry energy is calculated as a function of the baryonic density along with the related quantities such as the magnetic susceptibility and the Landau parameter G<SUB>0</SUB>. The main effect of the three-body force is to strongly reduce the degenerate Fermi gas magnetic susceptibility even more than the value with only two-body force. The equation of state is monotonically increasing with the density for all spin-aligned configurations studied here so that no any signature is found for a spontaneous transition to a ferromagnetic state.
文摘The three-body force effects on the equation of state and its iso-spin dependence of asymmetric nuclear matter and on the proton fraction in neutron star matter have been investigated within Brueckner-Hartree-Fock approach by using a microscopic three-body force. It is shown that, even in the presence of the three-body force, the empirical parabolic law of the energy per nucleon vs. isospin asymmetry is fulfilled in the whole asymmetry range and also up to high density. The three-body force provides a strong enhancement of symmetry energy at high density in agreement with relativistic approaches. It also shows that the three-body force leads to a much more rapid increasing of symmetry energy with density in relatively high density region and to a much lower threshold density for the direct URCA process to occur in a neutron star as compared to the predictions adopting only pure two-body force.
