Abstract:
By molecular dynamics simulations employing an embedded atom method potential, we have investigated structural transformations in single crystal Al caused by uniaxial strain loading along the 001], 011] and 111] directions. We find that the structural transition is strongly dependent on the crystal orientations. The entire structure phase transition only occurs when loading along the 001] direction, and the increased amplitude of temperature for 001] loading is evidently lower than that for other orientations. The morphology evolutions of the structural transition for 011] and 111] loadings are analysed in detail. The results indicate that only 20% of atoms transit to the hcp phase for 011] and 111] loadings, and the appearance of the hcp phase is due to the partial dislocation moving forward on {111}fcc family. For 011] loading, the hcp phase grows to form laminar morphology in four planes, which belong to the {111}fcc family; while for 111] loading, the hcp phase grows into a laminar structure in three planes, which belong to the {111}fcc family except for the (111) plane. In addition, the phase transition is evaluated by using the radial distribution functions.

Abstract:
Using the improved brick-wall model,the writers of the article have made some r esearches in the contribution made by the high spinning gravitation field to sta tic ball-symmetry black hole entropy. The research shows that in the static bal l-symmetry black hole, the quanta entropy of the gravitation field in whitch th e spinning is 2 is still in direct proportion to the horizon. When the same trun catin genes as theose in scalar guantity field are selected the quanta entropy i s two times in scalar quantity field, and four-sevenths of those in Dirac field .

Abstract:
The eigenstates and eigenspectrum of a charged particle in a one-dimensional semiconductor superlattice with an impurity under the action of a dc electric field are investigated employing the single-band tight-binding model. We find that the system undergoes a series of avoided crossings, at which resonant oscillations between the impurity and its nearest neighbour occur if appropriate conditions are met, suggesting an effective two-level approximation. This phenomenon shows that introducing an impurity in a perfect lattice provides a promising structure for the observation of terahertz radiation.

Abstract:
By molecular dynamics simulations employing an embedded atom model potential, we investigate the fcc-to-bcc phase transition in single crystal Al, caused by uniform compression. Results show that the fcc structure is unstable when the pressure is over 250 GPa, in reasonable agreement with the calculated value through the density functional theory. The morphology evolution of the structural transition and the corresponding transition mechanism are analysed in detail. The bcc (011) planes are transited from the fcc (111) plane and the (111) plane. We suggest that the transition mechanism consists mainly of compression, shear, slid and rotation of the lattice. In addition, our radial distribution function analysis explicitly indicates the phase transition of Al from fcc phase to bcc structure.

Abstract:
In terms of the improved brick-wall model, the statistical entropy of Dirac field in the most general spherically symmetric non-static black hole is calculated. It is shown that the entropy of the black hole is proportional to the area of event horizon at any time. It is noteworthy that the calculating formula for the dynamic proportional coefficient is obtained in this paper. Through calculating these dynamic proportional coefficients, the statistical entropies of the Dirac field in all kinds of the spherically symmetric non-static black hole can be obtained directly.

Abstract:
A statistical entropy of the Dirac field of static spherically symmetric black holes is gvien in this paper by using the improved brick wall model. The result shows that all these entrpies 7/2 times as large as the entropy of a scalar field when the same cutting factors are taken.

Abstract:
The quantum tunneling framework is adopted to investigate tunneling radiation of Barriola-Vilenkin black hole with a global monopole. We obtain a conclusion that the emission rate of massive particles is related with the change of Bekenstein-Hawking entropy. The emission rates of massless and massive particles take the same functional form. It is consistent with the underlying unitary theory.

Abstract:
Using entropy density near event horizon of the accelerating non-stationary black hole, the instantaneous radiant emittance is calculated, and we arrive at the conclusion that the instantaneous radiant emittance of black hole in a direction at any time is always proportional to the quartic power of temperature of the event horizon of black hole in that direction. It is found that the generalized Stefan-Boltzmann coefficient is no longer a constant, but a coefficient dynamically related to the rate of change of event horizon, the structure of space-time near event horizon and the radiation absorption coefficient of the black hole. It shows that an intrinsic relation between the gravitational field around the black hole and its thermal radiation must exist.