Systematic studies of fission fragment kinetic energy distributions by Langevin simulations

Fission fluctuation-dissipation dynamics of heavy nuclei has been studied using Langevin Monte Carlo simulations. The covariant form of the fission transport equation and the coefficients related to it are investigated. To learn about the influence of the dynamics from the ground state to the saddle point on the kinetic energy distributions we have studied various systems and compared the calculations both starting from the ground state and from the saddle point. Both the mean total kinetic energy of the fission fragments and its variances can fit with the experimental values in terms of a finite neck radius as scission condition.This work was supported by the National Natural Science Foundation of China.     

Comparison of the structures of an atomic three-valence-electron system with a nuclear three-valence-neutron system

A comparison has been made between the states of a 3-valence-electron system and a 3-valence-neutron system. The fermions are supposed to move in a sphere. The structures and internal motions of the head-states (the lowest of a given^2S+1 L ) of these systems havingL=0,S=1/2 and 3/2, and even and odd parity have been investigated. We have found that the symmetry governing the particular quantum system plays an essential role. In particular, all the nodal surfaces in the head-states originate from symmetry but not from dynamics. Consequently, the head-states of different dynamic systems have similar structures and similar internal motions.     

Radiation from hot spots orbiting an extreme Reissner-Nordström black hole

The general-relativistic effects of an extreme Reissner-Nordström black hole on the flux of radiation emitted by a hot spot orbiting the hole with a thin accretion disk are investigated. The light curves, the redshift factor, and the solid angle against the spot orbit position are given. The results are then compared with those of a spot orbiting a Schwarzschild black hole.