Showing papers in "Chinese Physics in 2004"
TL;DR: In this article, the authors extended the Green's function formalism to the semi-infinite networks by using the method of image and investigated the local field distribution near resonance for the impurity clusters with admittance 0 embedded in one semiinfinite network with 1.
Abstract: In the resonant composites, the formerly developed Green's function formalism (GFF) can be used to compute the local field distribution near resonance. In this paper, we extend the GFF in the infinite network to the semi-infinite networks by the method of image. Using the formalism, we investigate the local field distribution near resonance for the impurity clusters with admittance 0 embedded in one semi-infinite network with 1. With varying the admittance 2 of another semi-infinite network, we find that the local fields in the boundary experience great changes, especially at 2 = −1. The existence of the boundary enhances the localization of the fields within and around the metallic clusters. Therefore, the intensity of local field is influenced by the arrangement of impurity metallic bonds and its distance from the boundary.
96 citations
TL;DR: In this paper, the authors presented the results of the self-consistent calculations on the electronic structure of anatase phase of TiO2, which were performed using the full potential-linearized augmented plane wave method (FP-LAPW) in the framework of the density functional theory (DFT) with the generalized gradient approximation (GGA).
Abstract: This paper presents the results of the self-consistent calculations on the electronic structure of anatase phase of TiO2. The calculations were performed using the full potential-linearized augmented plane wave method (FP-LAPW) in the framework of the density functional theory (DFT) with the generalized gradient approximation (GGA). The fully optimized structure, obtained by minimizing the total energy and atomic forces, is in good agreement with experiment. We also calculated the band structure and the density of states. In particular, the calculated band structure prefers an indirect transition between valence and conduction bands of anatase TiO2, which may be helpful for clarifying the ambiguity in other theoretical works.
71 citations
TL;DR: In this article, the surface energies for 38 surfaces of fcc metals were calculated by using the modified embedded-atom method and the results showed that the average values of the surface energy are very close to the polycrystalline experimental data.
Abstract: The surface energies for 38 surfaces of fcc metals Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Rh and Ir have been calculated by using the modified embedded-atom method. The results show that, for Cu, Ag, Ni, Al, Pb and Ir, the average values of the surface energies are very close to the polycrystalline experimental data. For all fcc metals, as predicted, the close-packed (111) surface has the lowest surface energy. The surface energies for the other surfaces increase linearly with increasing angle between the surfaces (hkl) and (111). This can be used to estimate the relative values of the surface energy.
67 citations
TL;DR: In this paper, the structure of amorphous and crystalline Ge2Sb2Te5 thin films was investigated using XRD, Raman spectra and XPS.
Abstract: Ge2Sb2Te5 film was deposited by RF magnetron sputtering on Si (100) substrate. The structure of amorphous and crystalline Ge2Sb2Te5 thin films was investigated using XRD, Raman spectra and XPS. XRD measurements revealed the existence of two different crystalline phases, which has a FCC structure and a hexagonal structure, respectively. The broad peak in the Raman spectra of amorphous Ge2Sb2Te5 film is due to the amorphous –Te–Te– stretching. As the annealing temperature increases, the broad peak separates into two peaks, which indicates that the heteropolar bond in GeTe4 and the Sb–Sb bond are connected with four Te atoms and other units such as (TeSb) Sb–Sb (Te2) and (Sb2) Sb–Sb (Te2), where some of the four Te atoms in the above formula are replaced by Sb atoms, remain in crystalline Ge2Sb2Te5 thin film. And from the results of Raman spectra and XPS, higher the annealing temperature, more Te atoms bond to Ge atoms and more Sb atoms substitute Te in (Te2) Sb–Sb (Te2).
63 citations
TL;DR: In this paper, the exact bound state solutions of the Klein-Gordon equation and Dirac equation with scalar and vector pseudoharmonic oscillator potentials are obtained using supersymmetric quantum mechanics, shape invariance and alternative method.
Abstract: The exact bound state solutions of the Klein–Gordon equation and Dirac equation with scalar and vector pseudoharmonic oscillator potentials are obtained in this paper. Furthermore, we have used the supersymmetric quantum mechanics, shape invariance and alternative method to obtain the required results.
55 citations
TL;DR: A fourth-order circuit, by introducing additional breakpoints in the modified Chua oscillator, is implemented for the study of generation and synchronization of N-scroll chaotic attractors and confirms the consistency of theoretical calculation, numerical simulation and circuit experiment.
Abstract: Based on our previous works and Lyapunov stability theory, this paper studies the generation and synchronization of N-scroll chaotic and hyperchaotic attractors in fourth-order systems. A fourth-order circuit, by introducing additional breakpoints in the modified Chua oscillator, is implemented for the study of generation and synchronization of N-scroll chaotic attractors. This confirms the consistency of theoretical calculation, numerical simulation and circuit experiment. Furthermore, we give a refined and extended study of generating and synchronizing N-scroll hyperchaotic attractors in the fourth-order MCK system and report the new theoretical result, which is verified by computer simulations.
48 citations
TL;DR: The exact normalized bound state wavefunctions and energy equations of Klein-Gordon equation with equal scalar and vector ring-shaped Kratzer-type potential have been obtained in this article.
Abstract: The exact normalized bound state wavefunctions and energy equations of Klein–Gordon equation with equal scalar and vector ring-shaped Kratzer-type potential have been obtained.
43 citations
TL;DR: The LS-SVM achieves higher generalization performance than traditional neural networks and provides an accurate chaotic time series prediction and has fast convergence.
Abstract: We propose a new technique of using the least squares support vector machines (LS-SVMs) for making one-step and multi-step prediction of chaotic time series. The LS-SVM achieves higher generalization performance than traditional neural networks and provides an accurate chaotic time series prediction. Unlike neural networks' training that requires nonlinear optimization with the danger of getting stuck into local minima, training LS-SVM is equivalent to solving a set of linear equations. Thus it has fast convergence. The simulation results show that LS-SVM has much better potential in the field of chaotic time series prediction.
37 citations
TL;DR: In this paper, the exact bound state wavefunctions and energy equations of Klein-Gordon and Dirac equations are given with equal scalar and vector potential s(r) = v(r), = V(r)/2 = V0tanh2(r/d).
Abstract: The exact bound state wavefunctions and energy equations of Klein–Gordon and Dirac equations are given with equal scalar and vector potential s(r) = v(r) = V(r)/2 = V0tanh2(r/d). The relation between the energy equation and that of relativistic harmonic is discussed.
31 citations
TL;DR: In this article, the invariance of Birkhoffian equations under the infinitesimal transformations of groups is established and the condition under which the form invariance can lead to a non-Noether conserved quantity is deduced by relying on the total time derivative along the trajectory of the equations and two corollaries in special cases are presented.
Abstract: Based on the invariance of Birkhoffian equations under the infinitesimal transformations of groups, the definition and the criterion of a form invariance for a Birkhoffian system are established. The condition under which the form invariance can lead to a non-Noether conserved quantity and the form of the conserved quantity are deduced by relying on the total time derivative along the trajectory of the equations and two corollaries in special cases are presented. An example is finally given to illustrate the application of the results.
31 citations
TL;DR: A unified lattice Bhatnagar-Gross-Krook (ILBGK) model iDdQq for the incompressible Navier-Stokes equation is presented in this article.
Abstract: A unified lattice Bhatnagar–Gross–Krook (ILBGK) model iDdQq for the incompressible Navier–Stokes equation is presented. To test its efficiency, the lid-driven cavity flow in three-dimensional space for Reynolds number Re=3200 and span aspect ratio SAR=1, 2 and 3 is simulated in detail on a 48×48×(48×SAR) uniform lattice using the model. The test results agree well with those in previous experiments and numerical works and show the efficiency and strong numerical stability of the proposed ILBGK model.
TL;DR: In this paper, a new discrete spectral problem is introduced and the corresponding hierarchy of the lattice soliton equations are derived by means of the trace identity, through which the explicit solutions are shown.
Abstract: A new discrete spectral problem is introduced and the corresponding hierarchy of the lattice soliton equations are derived by means of the trace identity. We find a new Darboux transformation of the lattice soliton equation, through which the explicit solutions are shown.
TL;DR: In this article, the electron-phonon interaction in polar ternary mixed crystals is studied in the framework of the continuum model of Born and Huang and the random-element-isodisplacement model.
Abstract: Optical vibrations of the lattice and the electron–phonon interaction in polar ternary mixed crystals are studied in the framework of the continuum model of Born and Huang and the random-element-isodisplacement model. A normal-coordinate system to describe the optical vibration in ternary mixed crystals is correctly adopted to derive a new Frohlich-like Hamiltonian for the electron–phonon interaction including the unit-cell volume variation influence. The numerical results for the phonon modes, the electron–phonon coupling constants and the polaronic energies for several typical materials are obtained. It is verified that the nonlinearity of the electron–phonon coupling effects with the composition is essential and the unit-cell volume effects cannot be neglected for most ternary mixed crystals.
TL;DR: In this article, the authors derived the character formulae of representation-matrices of the physical property tensors for the one-dimensional (1D) quasicrystals.
Abstract: According to the group representation theory, we derive the character formulae of representation-matrices of the physical property tensors for the one-dimensional (1D) quasicrystals. Based on this, we have calculated the numbers of independent components of representation-matrices for thermal expansion coefficient tensors, piezoelectric coefficient tensors and elastic constant tensors under 31 point-groups for the 1D quasicrystals. Moreover, we have deduced the particular matrix forms of these tensors under the 31 point-groups. This is an important complement of quasicrystal physical property.
TL;DR: In this paper, the authors investigated the correlation between additive and multiplicative noises and found that the dependence of stochastic resonance on the initial conditions is entirely caused by the coupling strength λ between two noise terms.
Abstract: The phenomenon of stochastic resonance (SR) in a bistable nonlinear system with coupling between additive and multiplicative noises is investigated when the correlation between two noise terms is coloured. It is found that the signal-to-noise ratio (SNR) of the system is affected not only by the coupling strength λ between two noise terms, but also by the noise correlation time τ. The SNR is changed from a single peak, to two peaks with a dip and then to a monotonically decreasing function with noise strength. The dependence of the SR on the initial conditions is entirely caused by the coupling strength λ between two noise terms.
TL;DR: In this paper, a scheme for teleporting an unknown N-particle entangled W state via entanglement swapping is proposed, where N maximally entangled particle pairs are used as quantum channel.
Abstract: A scheme for teleporting an unknown N-particle entangled W state is proposed via entanglement swapping. In this scheme, N maximally entangled particle pairs are used as quantum channel. As a special case, the teleportation of an unknown four-particle entangled W state is studied.
TL;DR: In this paper, the magnetic properties and magnetocaloric effects of Mn5Ge3−xGax compounds with x = 0.6 and x =0.9 were reported.
Abstract: We report on the magnetic properties and magnetocaloric effects of Mn5Ge3−xGax compounds with x=0.1, 0.2, 0.3, 0.4, 0.6 and 0.9. All samples crystallize in the hexagonal Mn5Si3-type structure with space group P63/mcm and order ferromagnetically. The Curie temperature of these compounds decreases with increasing x, from 306K (x=0.1) to 274K (x=0.9). The average Mn magnetic moments increases with increasing Ga content, reaching a maximum value at x=0.6. The magnetic entropy changes in these compounds are determined from the temperature and field dependence of the magnetization using the thermodynamic Maxwell relation. The Ga substitution has two kinds of influence on the magnetocaloric effect (MCE) of Mn5Ge3. One is that the magnitude of the magnetic entropy change decreases, the other is that the MCE peak becomes broadened.
TL;DR: In this paper, the authors studied the relationship between the pull-off force and the transition parameter (or Tabor number) as well as the variation of the pulloff radius with the transition parameters in the adhesion elastic contact.
Abstract: In this paper, we study the relationship between the pull-off force and the transition parameter (or Tabor number) as well as the variation of the pull-off radius with the transition parameter in the adhesion elastic contact. Hysteresis models are presented to describe the contact radius as a function of external loads in loading and unloading processes. Among these models, we verified the hysteresis model from Johnson{Kendall{Roberts theory, based on which the calculated results are in good agreement with experimental ones.
TL;DR: In this article, an extended Jacobian elliptic function expansion method is presented and successfully applied to the nonlinear Schrodinger (NLS) equation and Zakharov equation.
Abstract: An extended Jacobian elliptic function expansion method is presented and successfully applied to the nonlinear Schrodinger (NLS) equation and Zakharov equation. We obtain some new solutions besides Fu et al's results. The results show that our method is more powerful to construct Jacobian elliptic function and can be applied to other nonlinear physics systems.
TL;DR: In this article, a scheme for probabilistic remote state preparation of a general qubit by using W states is proposed, which consists of the sender, Alice and two remote receivers Bob and Carol.
Abstract: In this paper we consider a scheme for probabilistic remote state preparation of a general qubit by using W states. The scheme consists of the sender, Alice and two remote receivers Bob and Carol. Alice performs a projective measurement on her qubit in the basis spanned by the state she wants to prepare and its orthocomplement. This allows either Bob or Carol to reconstruct the state with finite success probability. It is shown that for some special ensembles of qubits, the remote state preparation scheme requires only two classical bits, unlike the case in the scheme of quantum teleportation where three classical bits are needed.
TL;DR: In this article, the energy spectrum of Hartmann potentials is obtained in r and θ dimensions using supersymmetric quantum mechanics and shape invariance, and the result is consistent with that obtained by using the super-ymmetric WKB approximation.
Abstract: Using the method of supersymmetric WKB approximation, the energy spectrum of some noncentral separable potentials can be exactly obtained in r and θ dimensions. We take the Hartmann potential as an important example for its validation and the result is consistent with that obtained by using the supersymmetric quantum mechanics and shape invariance.
TL;DR: In this article, the retrospective time integration scheme presented on the principle of the self-memory of the atmosphere is applied to the mesoscale grid model MM5, constructing a mesoscalescale self-memorial model SMM5 and then the short-range prediction experiments of torrential rain are performed.
Abstract: The retrospective time integration scheme presented on the principle of the self-memory of the atmosphere is applied to the mesoscale grid model MM5, constructing a mesoscale self-memorial model SMM5 and then the short-range prediction experiments of torrential rain are performed in this paper. Results show that in comparison with MM5 the prediction accuracy of SMM5 is obviously improved due to its utilization of multiple time level past observations and the precipitation area and intensity predicted by SMM5 are closer to observational fields than those by MM5.
TL;DR: In this paper, the authors investigated the Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions and found that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 film.
Abstract: We report on Raman scattering of VO2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO2 films, compared with the stoichiometry VO2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO2 films is discussed.
TL;DR: In this paper, the atmospheric pressure surface barrier discharge (APSBD) in air has been used in killing Escherichia coli (E. coli) for 2 min and almost no bacterial colony in the sample after treatment by discharge plasma for two min.
Abstract: The atmospheric pressure surface barrier discharge (APSBD) in air has been used in killing Escherichia coli (E. coli). There is almost no bacterial colony in the sample after treatment by discharge plasma for 2 min. A diagnostic technique based on mass spectrum has been applied to the discharge gas and the mechanism of killing is discussed. Ozone and monatomic oxide are considered to be the major antimicrobial active species. There is almost no harmful by-product. The experiment proves that APSBD plasma is a very simple, effective and innocuous tool for sterilization.
TL;DR: In this article, a subalgebra of loop algebra A2 and its expanding loop algebra is constructed, and a generalized nonlinear coupled Schrodinger equation, the standard heat-conduction and a formalism of the well known Ablowitz, Kaup, Newell and Segur hierarchy are given.
Abstract: A subalgebra of loop algebra A2 and its expanding loop algebra are constructed. It follows that both resulting integrable Hamiltonian hierarchies are obtained. As a reduction case of the first hierarchy, a generalized nonlinear coupled Schrodinger equation, the standard heat-conduction and a formalism of the well known Ablowitz, Kaup, Newell and Segur hierarchy are given, respectively. As a reduction case of the second hierarchy, the nonlinear Schrodinger and modified Korteweg de Vries hierarchy and a new integrable system are presented. Especially, a coupled generalized Burgers equation is generated.
TL;DR: In this article, the relation between Lie symmetries and invariants of a system with a singular Lagrangian is investigated in phase space, and new dynamical equations of the system are given in canonical form and determining equations of Lie symmetry transformations are derived.
Abstract: According to the theory of the invariance of ordinary differential equations under the infinitesimal transformations of group, the relations between Lie symmetries and invariants of the mechanical system with a singular Lagrangian are investigated in phase space. New dynamical equations of the system are given in canonical form and the determining equations of Lie symmetry transformations are derived. The proposition about the Lie symmetries and invariants are presented. An example is given to illustrate the application of the result in this paper.
TL;DR: In this paper, a lattice Boltzmann method is developed to simulate three-dimensional solid particle motions in fluids, where a uniform grid is used and the exact spatial location of the physical boundary of the suspended particles is determined using an interpolation scheme.
Abstract: A lattice Boltzmann method is developed to simulate three-dimensional solid particle motions in fluids. In the present model, a uniform grid is used and the exact spatial location of the physical boundary of the suspended particles is determined using an interpolation scheme. The numerical accuracy and efficiency of the proposed lattice Boltzmann method is demonstrated by simulating the sedimentation of a single sphere in a square cylinder. Highly accurate simulation results can be achieved with few meshes, compared with the previous lattice Boltzmann methods. The present method is expected to find applications on the flow systems with moving boundaries, such as the blood flow in distensible vessels, the particle?flow interaction and the solidification of alloys.
TL;DR: In this article, a new isospectral problem is established by constructing a simple interesting loop algebra and a commutation operation of the loop algebra is as straightforward as a loop algebra A1.
Abstract: A new isospectral problem is established by constructing a simple interesting loop algebra. A commutation operation of the loop algebra is as straightforward as the loop algebra A1. It follows that a type of multi-component integrable hierarchy is obtained. This can be used as a general method.
TL;DR: In this article, a Jacobi elliptic function rational expansion is devised to uniformly construct a series of new double periodic solutions to (2+1)-dimensional asymmetric Nizhnik-Novikov-Veselov (ANNV) equation.
Abstract: By means of a new general ansatz and with the aid of symbolic computation, a new algebraic method named Jacobi elliptic function rational expansion is devised to uniformly construct a series of new double periodic solutions to (2+1)-dimensional asymmetric Nizhnik–Novikov–Veselov (ANNV) equation in terms of rational Jacobi elliptic function.
TL;DR: In this article, degree correlations of the Barabasi-Albert scale-free model with both analytical results and simulations are investigated and two neighbouring regions, a disassortative one for low degrees and a neutral one for high degrees, are found.
Abstract: Correlation between nodes is found to be a common and important property in many complex networks. Here we investigate degree correlations of the Barabasi–Albert (BA) scale-free model with both analytical results and simulations and find two neighbouring regions, a disassortative one for low degrees and a neutral one for high degrees. The average degree of the neighbours of a randomly picked node is expected to diverge in the limit of infinite network size. As a generalization of the concept of correlation, we also study the correlations of other scalar properties, including age and clustering coefficient. Finally we propose a correlation measurement in bipartite networks.