Showing papers in "Chinese Physics in 2003"
TL;DR: The exact normalized bound-state wavefunctions and energy equations of Klein-Gordon and Dirac equations were given in this article with equal scalar and vector potentials s(r = v(r) = V(r)/2 = (Ar-2-Br-1)/2
Abstract: The exact normalized bound-state wavefunctions and energy equations of Klein-Gordon and Dirac equations are given with equal scalar and vector potentials s(r) = v(r) = V(r)/2 = (Ar-2-Br-1)/2.
71 citations
TL;DR: In this paper, sufficient criteria have been established to ensure the global exponential stability of delayed cellular neural networks by using an approach based on delay differential inequality, which is simpler and more effective for a stability analysis of delayed system.
Abstract: Some sufficient criteria have been established to ensure the global exponential stability of delayed cellular neural networks by using an approach based on delay differential inequality. Compared with the method of Lyapunov functionals as in most previous studies, our method is simpler and more effective for a stability analysis of delayed system. Some previously established results in the literature are shown to be special cases of the present result.
53 citations
TL;DR: Based on the computerized symbolic system Maple and a Riccati equation, a general ansatz is presented by as mentioned in this paper. But the method is not suitable for solving nonlinear differential equations, such as non-travelling wave and coefficient functions.
Abstract: Based on the computerized symbolic system Maple and a Riccati equation, a Riccati equation expansion method is presented by a general ansatz. Compared with most of the existing tanh methods, the extended tanh-function method, the modified extended tanh-function method and generalized hyperbolic-function method, the proposed method is more powerful. By use of the method, we not only can successfully recover the previously known formal solutions but also construct new and more general formal solutions for some nonlinear differential equations. Making use of the method, we study the Bogoyavlenskii's generalized breaking soliton equation and obtain rich new families of the exact solutions, including the non-travelling wave and coefficient functions' soliton-like solutions, singular soliton-like solutions, periodic form solutions.
53 citations
TL;DR: In this paper, the periodic wave solutions for the Zakharov system of nonlinear wave equations and a long-short-wave interaction system are obtained by using the F-expansion method, which can be regarded as an overall generalization of Jacobi elliptic function expansion proposed recently.
Abstract: The periodic wave solutions for the Zakharov system of nonlinear wave equations and a long–short-wave interaction system are obtained by using the F-expansion method, which can be regarded as an overall generalization of Jacobi elliptic function expansion proposed recently. In the limit cases, the solitary wave solutions for the systems are also obtained.
44 citations
TL;DR: In this paper, the confined flow around a square cylinder mounted inside a two-dimensional channel (blockage ratio β = 1/8) was investigated by a newly developed incompressible nonuniform lattice-BGK model.
Abstract: The confined flow around a square cylinder mounted inside a two-dimensional channel (blockage ratio β = 1/8) was investigated in detail by a newly developed incompressible nonuniform lattice-BGK model. It is found that the vortex shedding behind the cylinder induces periodicity in the flow field and the periodicity of the flow will lose for Re>300. A detailed analysis for a range of Reynolds numbers between 1 and 500 was presented. Quantitative comparisons with other methods show that the model gives accurate results for complex flows.
42 citations
TL;DR: Solving Klein-Gordon equation with equal ring-shaped harmonic oscillator scalar and vector potentials, the authors obtained the exact normalized bound-state wave function and energy equation.
Abstract: Solving Klein-Gordon equation with equal ring-shaped harmonic oscillator scalar and vector potentials, we obtain the exact normalized bound-state wavefunction and energy equation.
41 citations
TL;DR: In this article, the homogeneous balance principle was used to derive Backlund transformations for nonlinear partial differential equations that have more nonlinear terms and more highest-order partial derivative terms.
Abstract: The homogeneous balance principle has been widely applied to the exploration of nonlinear transformation, exact solutions (especially solitary wave solution), dromion and similarity reduction to the nonlinear partial differential equations in mathematical physics. In this paper, we use the homogeneous balance principle to derive Backlund transformations for nonlinear partial differential equations that have more nonlinear terms and more highest-order partial derivative terms. With the aid of the Backlund transformations derived here, we could obtain exact solutions to the nonlinear partial differential equations. The Davey-Stewartson equation and the Nizhnik-Novikov-Veselov equation are considered as the examples.
35 citations
TL;DR: In this paper, a form invariance of canonical equations of generalized classical mechanics is defined for generalized classical systems and relations between form invariances, Noether symmetry and Lie symmetry are established.
Abstract: This paper presents a form invariance of canonical equations for systems of generalized classical mechanics. According to the invariance of the form of differential equations of motion under the infinitesimal transformations, this paper gives the definition and criterion of the form invariance for generalized classical mechanical systems and establishes relations between form invariance, Noether symmetry and Lie symmetry. At the end of the paper, an example is given to illustrate the application of the results.
33 citations
TL;DR: In this article, the authors investigated the transient third-order optical nonlinearity of the solutions of Metal(dmit)2/(mnt)2 salts in acetone by employing femtosecond optical Kerr gate measurement at 830 nm wavelength.
Abstract: We have investigated the transient third-order optical nonlinearity of the solutions of Metal(dmit)2/(mnt)2 salts in acetone by employing femtosecond optical Kerr gate measurement at 830 nm wavelength. An order of enhancement on the second-order hyperpolarizability is found for the above salts with central atoms of Cu and Ni. We have suggested an explanation for the enhancement based on the extension of electronic conjugation by the centring Cu or Ni atom.
32 citations
TL;DR: In this paper, the modulational instability of a nonlinear ion acoustic wave in a weakly relativistic warm unmagnetized nonthermal plasma whose constituents are an inertial ion fluid and nonthermally distributed electrons is investigated.
Abstract: An investigation has been made of modulational instability of a nonlinear ion acoustic wave in a weakly relativistic warm unmagnetized nonthermal plasma whose constituents are an inertial ion fluid and nonthermally distributed electrons. Up to the second order of the perturbation theory, a nonlinear Schrodinger type (NST) equation for the complex amplitude of the perturbed ion density is obtained. The coefficients of this equation show that the relativistic effect, the finite ion temperature and the nonthermal electrons modify the condition of the modulational stability. The association between the small-wavenumber limit of the NST equation and the oscillatory solution of the Korteweg-de Varies equation, obtained by a reductive perturbation theory, is satisfied.
32 citations
TL;DR: In this paper, the authors studied the Lie symmetries and conserved quantities of controllable nonholonomic dynamical systems, based on the infinitesimal transformation.
Abstract: This paper concentrates on studying the Lie symmetries and conserved quantities of controllable nonholonomic dynamical systems. Based on the infinitesimal transformation, we establish the Lie symmetric determining equations and restrictive equations and give three definitions of Lie symmetries before the structure equations and conserved quantities of the Lie symmetries are obtained. Then we make a study of the inverse problems. Finally, an example is presented for illustrating the results.
TL;DR: In this paper, it was found that after a tourmaline particle was bombarded by electron beams, a spot appeared on the surface of the sample and that one half of the spot was brighter than the other half under scanning electron microscope.
Abstract: Since Tetsujiro Kubo indirectly found the spontaneous polarization of tourmaline through absorbing copper ions in copper sulfate aqueous solutions in 1980s, there is no other evidence to demonstrate the existence of the spontaneous polarization in tourmaline. It was found that after a tourmaline particle was bombarded by electron beams, a spot appeared on the surface of the sample and that one half of the spot was brighter than the other half under scanning electron microscope. After tourmaline was treated for 2 h at 1223K and then bombarded by electron beams, the bombardment spot did not appear because the crystal structure of tourmaline is destroyed. The existence of the bombardment spot accounts for the spontaneous polarization. The shape and brightness of the bombardment spot not only shows the existence of a surface electric field induced by spontaneous polarization, but also the relation with the direction of the crystal plane of tourmaline.
TL;DR: In this article, an optical scheme for probabilistic teleporting entangled squeezed vacuum states (SVS) is proposed, in which the teleported state is a bipartite entangled SVS and the quantum channel is a tripartite SVS.
Abstract: An optical scheme for probabilistic teleporting entangled squeezed vacuum states (SVS) is proposed. In this scheme, the teleported state is a bipartite entangled SVS and the quantum channel is a tripartite entangled SVS. The process of the teleportation is achieved by using a 50/50 symmetric beamsplitter and photon detectors with the help of classical information.
TL;DR: In this paper, the perturbations to the symmetries and adiabatic invariants of the singular Lagrange system are discussed, and the conditions for the existence of the exact invariants and invariants are proved.
Abstract: Based on the theory of symmetries and conserved quantities of the singular Lagrange system, the perturbations to the symmetries and adiabatic invariants of the singular Lagrange systems are discussed. Firstly, the concept of higher-order adiabatic invariants of the singular Lagrange system is proposed. Then, the conditions for the existence of the exact invariants and adiabatic invariants are proved and their forms are given. Finally, an example is presented to illustrate these results.
TL;DR: In this article, the structure and phase transition of a 2D dusty plasma have been investigated in detail by molecular dynamics simulation and the simulation results are in favour of a two-step continuous transition for this kind of plasma.
Abstract: The structure and phase transition of a two-dimensional (2D) dusty plasma have been investigated in detail by molecular dynamics simulation. Pair correlation function, static structure factor, mean square displacement and bond angle correlation function have been calculated to characterize the structural properties. The variation of internal energy, shear modulus, particle trajectories and structural properties with temperature has been monitored to study the phase transition of the 2D dusty plasma system. The simulation results are in favour of a two-step continuous transition for this kind of plasma.
TL;DR: In this paper, the first-order field-induced itinerant-electron metamagnetic transition remains and brings about a large magnetic entropy change around room temperatures for the compounds.
Abstract: Magnetic properties and magnetic entropy change in La (Fe1-xMnx)11.7Si1.3Hy compounds have been investigated. A significant increase of the Curie temperature TC and a small increase of the saturation magnetizations µS have been observed after the introduction of interstitial H, which caused a slight volume expansion. The first-order field-induced itinerant-electron metamagnetic (IEM) transition remains and brings about a large magnetic entropy change around room temperatures for the compounds. The maximal magnetic entropy change is about 23.4, 17.7 and 15.9J/kgK under a magnetic field change from 0 to 5T for x=0.01, 0.02 and 0.03, respectively. Therefore, the compounds appear to be potential candidates for magnetic refrigerants around room temperatures.
TL;DR: In this paper, a generalized ansatz in the homogeneous balance method, the well-known Riccati equation and the symbolic computation were used to study a generalized Hirota-Satsuma coupled KdV system and a coupled MKdV equation.
Abstract: In this paper, we make use of a new generalized ansatz in the homogeneous balance method, the well-known Riccati equation and the symbolic computation to study a generalized Hirota-Satsuma coupled KdV system and a coupled MKdV equation, respectively. As a result, numerous explicit exact solutions, comprising new solitary wave solutions, periodic wave solutions and the combined formal solitary wave solutions and periodic wave solutions, are obtained.
TL;DR: In this article, the authors investigated the interaction of defects in one-dimensional hexagonal quasi-crystals using the complex variable function method and obtained the analytic solutions of elastic fields of interaction between a dislocation and a crack.
Abstract: The solution of elasticity problems involving the interaction between dislocations and cracks plays a fundamental role in many practical and theoretical applications. Although elasticity problems involving dislocation or cracks in quasi-crystals have been investigated in many papers, the analysis is limited to a single defect. This paper investigates the interaction of defects in one-dimensional hexagonal quasi-crystals using the complex variable function method. The interaction force between two parallel dislocations is presented and the analytic solutions of elastic fields of interaction between a dislocation and a crack are obtained. A version of the well-known Peach-Koehler formula in one-dimensional hexagonal quasi-crystals is given.
TL;DR: In this paper, a travelling-wave perturbation method was proposed to control the spatiotemporal dynamics in a cardiac model and it was numerically demonstrated that the method can successfully suppress the wave instability (alternans in action potential duration) in the one-dimensional case and convert spiral waves and turbulent states to the normal travelling wave states in the 2D case.
Abstract: We propose a travelling-wave perturbation method to control the spatiotemporal dynamics in a cardiac model. It is numerically demonstrated that the method can successfully suppress the wave instability (alternans in action potential duration) in the one-dimensional case and convert spiral waves and turbulent states to the normal travelling wave states in the two-dimensional case. An experimental scheme is suggested which may provide a new design for a cardiac defibrillator.
TL;DR: In this paper, the (1+1)-dimensional Whitham-Broer-Kaup and variant Boussinesq equations are solved using the standard Painleve analysis approach.
Abstract: Using the standard Painleve analysis approach, the (1+1)-dimensional Whitham-Broer-Kaup (WBK) and variant Boussinesq equations are solved. Some significant and exact solutions are given. We investigate the behaviour of the interactions between the multi-soliton-kink-type solution for the WBK equation and the multi-solitonic solutions and find the interactions are not elastic. The fission of solutions for the WBK equation and the fusions of those for the variant Boussinesq equation may occur after their interactions.
TL;DR: In this paper, the Tersoff-Brenner potential was used to describe the interaction between carbon nanotubes and thermal fluctuations to simulate the compression deformation of carbon nanoteubes under different temperature.
Abstract: The mechanical behaviour of carbon nanotubes is one of the basic research fields on the nanotube composites and nano machinery. Molecular dynamics is an effective way for investigating the behaviour of nano structure. The compression deformation of carbon nanotubes (CNTs) under different temperature is simulated, by using the Tersoff-Brenner potential to describe the interactions in CNTs. The results show that thermal fluctuations may induce the strained CNT to overcome the local energy barrier and develop the plastic deformation.
TL;DR: The communication using chaotic synchronization between two multi-mode Nd:YAG lasers has been investigated numerically and the digital signals can be successfully encoded into the spiky pulses and decoded through the subtraction of receiver output from the transmitted.
Abstract: The communication using chaotic synchronization between two multi-mode Nd:YAG lasers has been investigated numerically. The digital communication using multi-mode chaotic lasers is quite different from that using single mode lasers. By introducing a short break between two adjacent bits in the communication scheme, the digital signals can be successfully encoded into the spiky pulses and decoded through the subtraction of receiver output from the transmitted. Even when the two multi-mode lasers are not synchronized perfectly with certain deviations, the encoded digits can still be decoded correctly.
TL;DR: In this article, the authors investigated the problem of teleportation of an M-qubit state by using an entangled qudit pair as a quantum channel and showed that the teleportation of a multiparticle state can correspond to the teleoperation of a multi-dimensional state.
Abstract: We investigate the problem of teleportation of an M-qubit state by using an entangled qudit pair as a quantum channel and show that the teleportation of a multiparticle state can correspond to the teleportation of a multi-dimensional state. We also introduce a quantum-state converter composed of beamsplitter arrays, on/off-detectors and cross-Kerr couplers and demonstrate that the state conversion from an M-qubit to an N-dimensional qudit and vice versa can be implemented with this converter, where N = 2M. Based on this, an experimentally feasible scheme for the teleportation of an M-qubit via an entangled N-level qudit pair channel is proposed.
TL;DR: In this article, a scheme to probabilistically teleport an arbitrary and unknown three-particle state via a twoparticle non-maximally entangled state and a fourparticle nonsmooth state as the quantum channel was presented.
Abstract: We present a scheme to probabilistically teleport an arbitrary and unknown three-particle state via a two-particle non-maximally entangled state and a four-particle non-maximally entangled state as the quantum channel. With the help of Bell-state measurements, an arbitrary three-particle state can be perfectly teleported if a receiver introduces a collective unitary transformation. All kinds of unitary transformations are given in greater detail. This scheme can be generalized to the teleportation of an arbitrary and unknown multiparticle state.
TL;DR: In this article, the authors demonstrate the characteristics of relatively low saturation intensity using co-doped Nd, Cr:YAG as saturable absorber for passively mode locking the Nd-YAG laser.
Abstract: We demonstrate the characteristics of relatively low saturation intensity using co-doped Nd, Cr:YAG as saturable absorber for passively mode locking the Nd:YAG laser. The difference of the saturation intensity between Q-switched and mode-locked operation in co-doped Nd, Cr:YAG was only one to two orders of magnitude, while Cr:YAG was generally reported at a difference of five orders of magnitude. More than 80% mode locking modulation depth was achieved at an incident pump power of 4.4W, corresponding to an intracavity intensity of 6×104W/cm2, using a 68cm long plano-concave cavity.
TL;DR: In this paper, the periodic wave solutions expressed by Jacobi elliptic functions for the generalized Nizhnik-Novikov-Veselov equation were obtained using the Fexpansion method proposed recently.
Abstract: The periodic wave solutions expressed by Jacobi elliptic functions for the generalized Nizhnik-Novikov-Veselov equation are obtained using the F-expansion method proposed recently. In the limiting cases, the solitary wave solutions and other types of travelling wave solutions for the system are obtained.
TL;DR: In this paper, a new integrable system is obtained by making use of Tu's scheme, which possesses a bi-Hamiltonian structure, and an integrably coupling of the system obtained is given.
Abstract: A subalgebra of loop algebra A2 is established. Therefore, a new isospectral problem is designed. By making use of Tu's scheme, a new integrable system is obtained, which possesses bi-Hamiltonian structure. As its reductions, a formalism similar to the well-known Ablowitz-Kaup-Newell-Segur (AKNS) hierarchy and a generalized standard form of the Schrodinger equation are presented. In addition, in order for a kind of expanding integrable system to be obtained, a proper algebraic transformation is supplied to change loop algebra A2 into loop algebra A1. Furthermore, a high-dimensional loop algebra is constructed, which is different from any previous one. An integrable coupling of the system obtained is given. Finally, the Hamiltonian form of a binary symmetric constrained flow of the system obtained is presented.
TL;DR: The results of wavelet analysis show that the RT scheme can better extract the useful information from the initial fields, i.e. to memorize many main initial characteristics, such as periods, thus offering a new approach to the short-term climate numerical prediction.
Abstract: The evaluation of the applicability of a retrospective multi-time-level scheme (RT scheme) is carried out on the basis of comparison with the common leapfrog scheme (LF scheme) and its derivatives and modified BOTT's positive-definite schemes used in atmospheric models. Two rational flow field tests confirm that at least the BOTT scheme tested may be applied, but apparently the best results are obtained by the RT scheme. The results of wavelet analysis show that the RT scheme can better extract the useful information from the initial fields, i.e. to memorize many main initial characteristics, such as periods, thus offering a new approach to the short-term climate numerical prediction.
TL;DR: In this paper, a set of Lie symmetries and conservation laws for a rotational relativistic Birkhoffian system is given under infinitesimal transformations, and a new type of non-noether conserved quantities are directly obtained from Lie symmetry of the system.
Abstract: For a rotational relativistic Birkhoffian system, a set of the Lie symmetries and conservation laws is given under infinitesimal transformations. On the basis of the invariance of rotational relativistic Birkhoffian equations under infinitesimal transformations, Lie symmetrical transformations of the system are constructed, which only depend on the Birkhoffian variables. The determining equations of Lie symmetries are given and a new type of non-noether conserved quantities are directly obtained from Lie symmetries of the system. An example is given to illustrate the application of the results.
TL;DR: In this paper, the amplitude equations of all the models were put into a general form, that is, the new amplitude equation, and the stationary properties of the laser intensity for the white-gain model were investigated.
Abstract: The white-gain model and the white-loss model of a single-mode laser are investigated in the presence of cross-correlations between the real and imaginary parts of quantum noise as well as pump noise. It was found that, like the white cubic model (2001 Chin. Phys. Lett. 18 370), the amplitude equations are all decoupled from the phase equations for the two models and the same novel term appears in the amplitude equations of the two models. So we can put the amplitude equations of all the models into a general form, that is, the new amplitude equation. We further use this new amplitude equation to study specifically the stationary properties of the laser intensity for the white-gain model.