International Journal of Modern Physics B

A spin-polarized first-principles calculation of the atomic and electronic structure of the graphene/Ni(111) interface is studied. The electronic structure of the graphene layer is strongly modified by interaction with the substrate and a behavior where magnetic moments are localized at the edges of nanoscale holes of isolated graphene does not happen in the defect-graphene/Ni(111) system. The magnetic moment of the surface nickel atoms is lowered in the presence of the graphene layer and nanoscale holes of graphene, which control the strength of the hybridization between electronic states of graphene and Ni substrate. Our findings show that an electron spin in the graphene/Ni(111) interface can be manipulated in a controlled way and have important implications for graphene-based spintronic devices.

In this paper, we propose a new lag synchronization scheme for a general class of chaotic systems with external disturbance. Based on Lyapunov theory and linear matrix inequality (LMI) approach, the lag synchronization controller is presented to not only guarantee exponential lag synchronization but also reduce the effect of external disturbance to an norm constraint. The proposed controller can be obtained by solving a convex optimization problem represented by the LMI. As an application of the proposed method, the lag synchronization problem for Genesio–Tesi system is investigated.

A modified generalized Morse (mGM) equation of state (EOS) is proposed that can incorporate the cohesive energy data correctly. It is compared with a four-parameter modified Rose EOS (MR EOS) which is proposed by following the Rose's approach and the Vinet EOS. The MR, mGM and Vinet EOSs are applied to five transition metals to fit all experimental compression data available. The results show that for all pressure ranges the mGM EOS gives the best fitting results. From the comparison of variation of pressure and energy versus compression ratio between MR and mGM EOS, it is clear that the pressure and energy of the MR EOS oscillate both in the neighborhood of (V/V₀) ≈ 0.005 and in the range (V/V₀) > 1. Such oscillations are physically incorrect, and the tendency of the mGM EOS are physically correct both in the neighborhood of (V/V₀) ≈ 0.005 and in the range (V/V₀) > 1. Generally speaking, the mGM EOS has evident advantage among the three EOSs, and the MR EOS's practical applications are seriously limited because of the physically incorrect oscillations.

A sol-gel method is investigated to synthesize CuO–ZrO₂ nanoparticles as catalyst for hydrogen production from methanol. Finer precursor nanoparticles give rise to larger specific areas in catalyst which result in a high hydrogen production. The effects of some critical process parameters on the sol-gel synthesis of CuO–ZrO₂ nanoparticles are studied. These parameters are affected on synthesis of CuO–ZrO₂ when it is prepared with sol-gel method. Particle size and distribution are considered as the results. The parameters including the effect of calcination temperature, aging temperature, nature and concentration of catalyst (acidic or basic conditions), H₂O/precursor molar ratio, and chelating agent that have been identified as most important, are focused. It is found that the calcination temperature strongly influenced the morphology and interaction between the active species and support, and hence the structure and catalytic performance. Nature and concentration of catalyst (pH value), chelating agent, (H₂O/precursor) molar ratio and also aging temperature have influence on the nanoparticles. Thus, by controlling these factors, it is possible to vary the morphology and properties of the sol-gel-derived inorganic network over wide ranges. Morphology, particle size and distribution, phase evaluation, structure, and chemical analysis of the products are investigated by SEM, TEM, DTA/TG, XRD and EDX respectively.

A soliton hierarchy of multicomponent KN equations is generated from an arbitrary order matrix spectral problem, along with its bi-Hamiltonian formulation. Adjoint symmetry constraints are presented to manipulate binary nonlinearization for the associated arbitrary order matrix spectral problem. Finally, a class of integrable coupling systems of the multicomponent KN soliton equation hierarchy is obtained using Ma's method associated with enlarging spectral problems [W. X. Ma, Phys. Lett. A316, 72–76 (2003)].

We present a scheme for realizing open-destination and controlled teleportation of a single-qubit rotation gate, albeit probabilistically, by using partially entangled pairs of particles. In the scheme, a quantum rotation is faithfully teleported onto any one of N spatially separated receivers under the control of the (N-1) unselected receivers in a network. We first present the three-destination and controlled teleportation of a rotation gate by using three partially entangled pairs, and then generalize the scheme to the case of N-destination. In our scheme, the sender's local generalized measurement described by a positive operator-valued measurement (POVM) lies at the heart. We construct the required POVM. The fact that deterministic and exact teleportation of a rotation gate could be realized using partially entangled pairs is notable.

This paper looks at the mass transfer effects on the unsteady two-dimensional and magnetohydrodynamic flow of an upper-convected Maxwell fluid bounded by a stretching surface. Homotopy analysis method is used for the development of series solution of the arising nonlinear problem. Plots of velocity and concentration fields are displayed and discussed. The values of surface mass transfer and gradient of mass transfer are also tabulated.

In this paper, the drive system and the response system can be in a state of linear generalized synchronization via transmitting single signal. By means of a transitional system, the response system is obtained by variable replacement method. Chen system and hyperchaotic Chen system are used as examples in numerical simulations. Simulation results show the effectiveness of the method.

A system composed of a single-Cooper-pair box irradiated by a single-mode quantized field has been considered. The entanglement relative to the mixedness μ and the detuning δ is investigated with negative partial transpose. It is found that in the case of initial mixed state, the entanglement is weakened, but increases as time evolves. For a detuned system, the entanglement is further suppressed but more stationary than that for a resonant system.

In this work, we present a simple approximate transfer matrix method for 2D and 3D Ising ferromagnet to calculate spontaneous magnetization of the system. The critical coupling strength K_c of 2D and 3D Ising models in reduced transfer matrix approximation is obtained quite accurately by simple improvements over the mean field theory. The important physical effect we include is the some of the fluctuations effects of the systems directly with help of this method. We predict from the spontaneous magnetization curve that the critical coupling strength K_c=J/k_BT = 0.401 and 0.245 for two-dimensional (2D) and three-dimensional (3D) systems, respectively.

There is a continuing interest in determining the characteristics of unreacted plastic bonded explosives (PBXs). In this work, a Particle Velocity Comparing Method to determine the unreacted Hugoniot of heterogeneous explosive using magnetic particle velocity gauge is described. The Hugoniot for the PBXs has been measured using flyer driven by planar wave lens. A superposition principle considering unreacted explosives as composite and porous materials is presented, the unreacted Hugoniot of explosives is calculated, and the results of calculation are compared with the experiment results.

An alternative scheme is proposed in this paper to realize an n-qubit Fredkin gate with superconducting quantum-interference device (SQUID) in cavity QED. The multiqubit logical gate is essentially accomplished by a sequence of operations on only two SQUIDs in a large-detuned cavity. In the scheme, the two logical states of a qubit are presented by the two lowest states of a SQUID and the cavity is always in vacuum state so that the limit on the cavity is not serious.

Ultra-thin platinum (Pt) films were deposited on Si(100) substrates at 160°C by magnetron sputtering and subsequently annealed to form silicides. The thickness of the Pt_xSi films was found to be approximately 4 nm as determined by transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) analysis shows that these films consist of PtSi and Pt₂Si phases, and a multi-layer configuration of SiO_x/PtSi/Pt₂ Si/Si was detected by angle-resolved XPS. However, the Pt₃Si phase was not detected by X-ray diffraction (XRD).