International Journal of Modern Physics B

Mechanical energy, such as sound waves and impulses, have been used to detect shallow buried objects for more than half a century. Yet, very little is understood about how mechanical energy propagates into one of the simplest kinds of soil, namely, a granular bed. Here we present an overview of the state of the art in our understanding of mechanical energy propagation in granular beds.

In this work, the effect of thin films on the orientational, thermotropic and optical properties and on the peculiarities of the nematic–isotropic liquid phase transition has been carried out.

The planar textures of MBBA+EBBA eutectic mixture on the surfaces coated with Al₂O₃ and ZrO₂ thin films have been obtained. The optical and thermodynamical parameters of the obtained, oriented textures have been determined. The effect of thin films on the temperature width of heterophase region and on the nematic–isotropic liquid phase transition temperatures has been investigated. The shift of the phase transition temperatures and the change of the temperature width of the heterophase region have been revealed.

For the analysis of peculiarities of the nematic–isotropic liquid phase transition and the heterophase regions of this transition, the mean field theory has been used.

In this paper, we have investigated the interplay of the asymmetric exclusion process (ASEP) of parallel updated rules with "Langmuir kinetics" (LK) by equipping the ASEP system with the additional feature of local particle creation at empty sites with rate ω_a and annihilation with rate ω_d. Two slightly different models are proposed. It is shown that the phase separation may occur in both models. However, in one model, the maximum flow phase may occur but in the other model, there only exists the constant bulk density phase.

In this paper, we have studied the chiral lipid bilayers with the tilted fluid phase where the orientation of the molecular tilt varies as a function of the cylindrical coordinates. The rigorous solution of the equation related to the orientation of the long molecular axis is obtained, which describes the property of the tubules with a modulation in the tilt. When the angle of the molecular director is independent of the cylindrical coordinates θ, z, the patterns formed by chiral molecules can be degenerated to the right-handed helix, the left-handed helix, the straight lines, and the circles. The curvature and torsion of the corresponding curves are given explicitly, which denotes the winding of the molecules around the cylinder. We find also that the angle between the director of the molecule and the local normal direction of the cylinder increases if the radius of the cylinder reduces when the tilted angle ϕ from the equator of the cylinder is uniform.

Intrinsic microcrystalline silicon films have been prepared using very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at low temperature. The effect of silane concentration and power density on the deposition rate and crystallinity of silicon films has been investigated. The Raman spectra indicates a phase transition from microcrystalline to amorphous phase at silane concentrations of higher than 6%. A growth rate of microcrystalline films as high as 6.6 A/s is achieved at a silane concentration of 6% and the crystalline volume fraction X_c is 39%. We have also observed that the decrease of power density shifts the phase transition to low silane concentration.

We identify a conformal field theory (CFT) that describes the Yang–Lee edge singularity of the 2-dimensional (2D) 3-state Potts model. The identification is based on a comparison of finite-size scaling measurements to predictions for conformal minimal models. The comparison shows that the Yang–Lee edge singularities of the 2D 3-state Potts and the 2D Ising models are in the same universality class.

The structural and dielectric properties of a PZN-PLZT solid solution were investigated. The formation of a single phase was studied by the addition of PLZT (8/60/40) in the present system. With the increase of PLZT, the content of the pyrochlore phase decreased significantly and PZN ceramics with 100% perovskite phase could be achieved with x>0.6. Dielectric properties were investigated as a function of temperature and frequency. The ferroelectric hysteresis loop shows typical characteristics of ferroelectrics.

The actinide compounds exhibit a variety of unusual ground states. These states are dominated by the strong electron-electron correlations that are not included in normal density-functional electronic band-structure calculation with the local density approximation. These correlations are taken into account in the local density approximation +U (LDA+U) method.

We have calculated the Coulomb repulsion term U for uranium in USn₃ compound, and investigated the total and partial DOS for USn₃ using LDA+U method. The LDA+U results for USn₃ have been compared with similar results from a ThSn₃ model calculation through which the number of 5f electrons outside the U muffin-tin sphere in USn₃ has been deduced. We have also calculated the electric field gradient (EFG), which may be regarded as a measure of the asymmetry in charge distribution, at the Sn site in USn₃ in LDA, LDA+SO and LDA+SO+U methods, and have shown that the Coulomb repulsion term does not introduce any considerable effect on the electric field gradient at the Sn site.