[en] We investigate the cosmological attractor of the minimally coupled, self-interacting phantom field with a positive energy density but negative pressure. It is proved that the phantom cosmology is rigid in the sense that there exists a unique attractor solution. We plot the trajectories in the phase space numerically for the phantom field with three typical potentials. Phase portraits indicate that an initial kinetic term decays rapidly and the trajectories reach the unique attractor curve. We find that the curve corresponds to the slow-climb solution

[en] The Izergin-Korepin model on a semi-infinite lattice is diagonalized by using the level-one vertex operators of the twisted quantum affine algebra U_q[A⁽²⁾₂]. We give the bosonization of the vacuum state with zero particle content. Excitation states are given by the action of the vertex operators on the vacuum state. We derive the boundary S-matrix. We give an integral expression of the correlation functions of the boundary model, and derive the difference equations which they satisfy

[en] Using a 2.5-dimensional MHD simulation, we investigate the role played by the inner coronal null point in the formation and evolution of solar quiescent prominences. The flux rope is characterized by its magnetic fluxes, the toroidal magnetic flux Φ _p and the poloidal flux Φ_ψ. It is found that for a given Φ _p, the catastrophe does not occur in the flux rope system until Φ_ψ increases to a critical point. Moreover, the magnetic flux of the null point is the maximum value of the magnetic flux in the quadrupole background magnetic field, and represented by ψ _N. The results show that the bigger ψ _N usually corresponds to the smaller catastrophic point, the lower magnetic energy of the flux rope system, and the lesser magnetic energy inside the flux rope. Our results confirm that catastrophic disruption of the prominence occurs more easily when there is a bigger ψ _N. However, ψ _N has little influence on the maximum speed of the coronal mass ejections (CMEs) with an erupted prominence. Thus we argue that a topological configuration with the inner coronal null point is a necessary structure for the formation and evolution of solar quiescent prominences. In conclusion, it is easier for the prominences to form and to erupt as a core part of the CMEs in the magnetic structure with a greater ψ _N

[en] Quasi-aligned Zn_1-xMg_xO nanorods have been synthesized on Si substrates by thermal evaporation. The Mg content (x) in Zn_1-xMg_xO nanorods was 0.23, higher than that in the source materials by a factor of about 1.9. Zn_1-xMg_xO (x = 0.23) nanorods showed a wurtzite ZnO structure with the c-axis constant of 0.5179 nm. The nanorods grew along the [0 0 0 1] crystal direction and had uniform and flat hexagonal planes with diameters of about 200 nm. Photoluminescence measurements revealed that the predominant ultraviolet (UV) emission of Zn_1-xMg_xO (x = 0.23) nanorods was centred at 3.78 eV, with a ∼0.51 eV blueshift from the UV emission line (3.27 eV) of ZnO nanorods. This blueshift indicated the bandgap engineering in nanostructures of Zn_1-xMg_xO ternary alloys

[en] Epitaxial La_1.85Sr_0.15CuO_4+δ thin films were successfully deposited onto SrTiO₃(100) substrates by using on-axis DC magnetron sputtering. Several different annealing and cooling processes were performed in studying the influence of the annealing processes for La_1.85Sr_0.15CuO_4+δ thin films grown on SrTiO₃ substrates. By using a quenching method, we found that the method can tune the superconducting transition temperature in a large viable range without changing the La/Sr ratio. We suggest that this effect is probably induced by releasing tensile strain for La_1.85Sr_0.15CuO_4+δ thin films grown on SrTiO₃ substrates

[en] Following the two-stage catastrophic flux rope model presented by Zhang et al., we investigate how magnetic flux emergence affects the formation and evolution of solar quiescent prominences. The magnetic properties of the flux rope are described with its toroidal magnetic flux per radian Φ_p and poloidal flux Φ_ψ, and Φ_p is defined as the emerging strength (ES) of the magnetic flux. After the first catastrophe, the quiescent prominences are supported by the vertical current sheet and located in cavities below the curved transverse current sheet in the inner corona, for which both ES and Φ_ψ are in the certain ranges. We calculate the strength range as 0.25 < ES < 0.50 for the quadrupolar field, and obtain the equation Φ_pΦ_ψ = const., that is, the relationship between Φ_p and Φ_ψ of the emerging flux for which the quiescent prominences are formed in the inner corona. After the second catastrophe, the quiescent prominences would either fall down onto the solar surface or erupt as an important part of coronal mass ejections. During the eruption of the quiescent prominences, most of the magnetic energy in the flux rope is lost, and less than half of the energy loss of the rope is released in the form of Alfvèn waves. We argue that there would be two important conditions required for the formation and eruption of solar quiescent prominences, a complicated source region and emerging toroidal magnetic flux that exceeds a critical strength

[en] Thermally activated flux flow and vortex glass transition of the recently discovered SmFeAsO_0.9F_0.1 superconductor are studied in magnetic fields up to 9.0 T. The thermally activated energy is analyzed in two analytic methods, of which one is conventional and generally used, while the other is closer to the theoretical description. The thermally activated energy values determined from both methods are discussed and compared. In addition, several critical magnetic fields determined from resistivity measurements are presented and discussed.

[en] Temperature-dependent photoluminescence (PL) properties of ZnO/Zn_0.9Mg_0.1O multi-quantum wells (MQWs) grown on Si (1 1 1) substrates by pulsed laser deposition have been investigated. For MQWs with well widths of 14 and 3 nm, the predominant excitonic emission in the whole temperature range (8-300 K) is attributed to bound excitons and localized excitons, respectively. The effect of quantum confinement on enhancing the intensity of the excitonic emission is clearly observed in the MQWs with well width of 3 nm, while the effect on blue-shifting the emission energy is not distinct, most probably due to the quantum confined Stark effect. The PL peak from the barrier layers shows an 'S'-shaped shift with increasing temperature due to localization of carriers in the potential minima induced by composition and interface fluctuations. The depth of the potential well is determined to be ∼15 meV

[en] We epitaxially deposited a series of differently doped (Ca_xLa_1-x)(Ba_1.75-xLa_0.25+x)Cu₃O_y thin films by in situ dc magnetron sputtering. Samples with x = 0.1 and 0.5 were prepared. The sputtering condition, annealling processes, and cooling methods were carefully studied. A quenching method has been developed. By using this method, a series of differently doped samples were routinely obtained. The structures of the thin films were studied by x-ray diffraction with θ-2θ, rocking curve, and Φ scans. The surface morphologies of the thin films were analysed by atomic force microscopy. The study shows that the thin films are highly c-axis oriented and constructed from three-dimensional stacking islands

[en] Based on time-dependent MHD simulation, we investigate how physical features in the solar atmosphere affect the evolution of coronal mass ejections (CMEs). It is found that temperature and density play a crucial role in CME initiation. We argue that lower temperature facilitates the catastrophe's occurrence, and that the CMEs which initiate in low density could gain lower velocity. In our numerical experiment, by employing different values of β, the resulting eruptions of either slow or fast events may be obtained.