Results 1 - 10 of 19
Results 1 - 10 of 19. Search took: 0.016 seconds
|Sort by: date | relevance|
[en] Based on the anisotropic London theory, we derive an expression for the elastic matrix of flux superlattices in anisotropic superconductors. The elastic tilt and compressional modulus in the long wavelength limit are also given. (orig.)
[en] The interaction potential of two like-charged colloid spheres with nonuniform surface charge distribution suspended in an electrolyte confined in a long charged cylinder wall is calculated in this paper. Two models of boundary conditions on the cylinder wall are considered. One is the fixed potential model, and the other is the fixed charge density model. The confinement makes a quantitative or even qualitative change to the spheres' interaction compared with the unconfined system. A long-ranged attraction emerges in the confined system, though they are repulsive in the unconfined system under the same other conditions
[en] Metropolis Monte Carlo simulation was used to study the response of uniformly charged dsDNA to strong stretching at different values of the ratio rs/lp. Equilibrium distributions of dsDNA conformations for different values of the Debye screening length were simulated using a discrete worm-like chain model. The simulations show that the entropic elasticity of the dsDNA with a Yukawa-type pair potential depends on the screening length, and the strong force behavior differs from that of the electrostatically neutral dsDNA chain
[en] The position-dependent entanglement dynamics of two qubits embedded in a leakage cavity is investigated. The two qubits are initialled in Bell states and the cavity mode is taken as a standing wave. It is found that (i) the dynamics of the Bell states can be divided into two groups according to one-photon entangled states and two-photon entangled states; (ii) the entanglement life of the one-photon entangled states can be kept as long as possible if we put the two qubits at certain positions; (iii) at larger detuning, the entanglement dynamics manifests more robustly
[en] A general method is proposed to design a cylindrical cloak, concentrator and superscatterer with an arbitrary cross section. The method is demonstrated by the design of a perfect electrical conductor (PEC) reshaper which is able to reshape a PEC cylinder arbitrarily by combining the concept of cloak, concentrator and superscatterer together. Numerical simulations are performed to demonstrate its properties.
[en] We show that the widely used parabolic approximation to the Equation of State (EOS) of asymmetric nuclear matter leads systematically to significantly higher core-crust transition densities and pressures. Using an EOS for neutron-rich nuclear matter constrained by the isospin diffusion data from heavy-ion reactions in the same sub-saturation density range as the neutron star crust, the density and pressure at the inner edge separating the liquid core from the solid crust of neutron stars are determined to be 0.040 fm-3≤ρt≤0.065 fm-3 and 0.01 MeV/fm3≤Pt≤0.26 MeV/fm3, respectively. Implications of these constraints on the Vela pulsar are discussed.
[en] In order to extend the service lifetime of Ti-6Al-4V-based components, friction and wear behaviors of Ti-6Al-4V alloys needed to be further improved. Laser additive manufacturing with a moving laser beam was used to prepare (Ti-6Al-4V)/10 wt.% Ag samples, on a three-dimensional RC-SLM400 printer with laser powers of 2-10 kW. (Ti-6Al-4V)/10 wt.% Ag samples were successfully printed using spherical powders prepared by gas atomization process (SPGAP) and combustion reaction (SP-CR). The tribological properties of the as-prepared samples sliding against Si3N4 balls were examined using a ball-on-disk tribometer. The results showed that the tribological behavior of (Ti-6Al-4V)/10 wt.% Ag printed by SP-CR was better than that of the sample printed by SPGAP. The low friction and reduced wear were mainly attributed to the formation of the lubrication layer containing large amounts of silver, which can exhibit an excellent deformation and plastic ductility. It effectively reduced the friction resistance and material loss and provided the good lubrication for 0-80 min, resulting in low friction and reduced wear of the samples prepared by SP-CR.
[en] The transition density ρ t and pressure Pt at the inner edge separating the liquid core from the solid crust of neutron stars are systematically studied using a modified Gogny (MDI) and 51 popular Skyrme interactions within well established dynamical and thermodynamical methods. First of all, it is shown that the widely used parabolic approximation to the full equation of state (EOS) of isospin asymmetric nuclear matter may lead to huge errors in estimating the transition density and pressure, especially for stiffer symmetry energy functionals E sym(ρ), compared to calculations using the full EOS within both the dynamical and thermodynamical methods mainly because of the energy curvatures involved. Thus, fine details of the EOS of asymmetric nuclear matter are important for locating accurately the inner edge of the neutron star crust. Second, the transition density and pressure decrease roughly linearly with increasing slope parameter L of E sym(ρ) at normal nuclear matter density using the full EOS within both the dynamical and thermodynamical methods. It is also shown that the thickness, fractional mass, and moment of inertia of the neutron star crust are all very sensitive to the parameter L through the transition density ρ t whether one uses the full EOS or its parabolic approximation. Moreover, it is shown that E sym(ρ) constrained in the same subsaturation density range as the neutron star crust by the isospin diffusion data in heavy-ion collisions at intermediate energies limits the transition density and pressure to 0.040 fm-3 ≤ρ t ≤ 0.065 fm-3 and 0.01 MeV fm-3 ≤Pt ≤ 0.26 MeV fm-3, respectively. These constrained values for the transition density and pressure are significantly lower than their fiducial values currently used in the literature. Furthermore, the mass-radius relation and several other properties closely related to the neutron star crust are studied by using the MDI interaction. It is found that the newly constrained ρ t and Pt together with the earlier estimate of ΔI/I>0.014 for the crustal fraction of the moment of inertia of the Vela pulsar impose a more stringent constraint of R ≥ 4.7 + 4.0M/M sun km for the radius R and mass M of neutron stars compared to previous studies in the literature.
[en] In this article, three models with different isospin and momentum dependence are used to study the thermodynamical properties of asymmetric nuclear matter. They are isospin and momentum-dependent MDI interaction constrained by the isospin diffusion data of heavy ion collision, the momentum-independent MID interaction and the isoscalar momentum-dependent eMDYI interaction. Temperature effects of symmetry energy, mechanical and chemical instability and liquid-gas phase transition are analyzed. It is found that for MDI model the temperature effects of the symmetry energy attribute from both the kinetic and potential energy, while only potential part contributes to the decreasing of the symmetry energy for MID and eMDYI models. We also find that the mechanical instability, chemical instability and liquid-gas phase transition are all sensitive to the isospin and momentum dependence and the density dependence of the symmetry energy. (authors)
[en] Thermal properties of asymmetric nuclear matter are studied within a self-consistent thermal model using an isospin and momentum-dependent interaction (MDI) constrained by the isospin diffusion data in heavy-ion collisions, a momentum-independent interaction (MID), and an isoscalar momentum-dependent interaction (eMDYI). In particular, we study the temperature dependence of the isospin-dependent bulk and single-particle properties, the mechanical and chemical instabilities, and liquid-gas phase transition in hot asymmetric nuclear matter. Our results indicate that the temperature dependence of the equation of state and the symmetry energy are not so sensitive to the momentum dependence of the interaction. The symmetry energy at fixed density is found to generally decrease with temperature and for the MDI interaction the decrement is essentially due to the potential part. It is further shown that only the low momentum part of the single-particle potential and the nucleon effective mass increases significantly with temperature for the momentum-dependent interactions. For the MDI interaction, the low momentum part of the symmetry potential is significantly reduced with increasing temperature. For the mechanical and chemical instabilities as well as the liquid-gas phase transition in hot asymmetric nuclear matter, our results indicate that the boundaries of these instabilities and the phase-coexistence region generally shrink with increasing temperature and are sensitive to the density dependence of the symmetry energy and the isospin and momentum dependence of the nuclear interaction, especially at higher temperatures