Showing papers in "Chinese Physics Letters in 2000"
TL;DR: Numerical results show that the RNN proposed here is a very powerful tool for making prediction of chaotic time series.
Abstract: A new proposed method, i.e. the recurrent neural network (RNN), is introduced to predict chaotic time series. The effectiveness of using RNN for making one-step and multi-step predictions is tested based on remarkable few datum points by computer-generated chaotic time series. Numerical results show that the RNN proposed here is a very powerful tool for making prediction of chaotic time series.
95 citations
TL;DR: In this paper, the quantization of inductance-capacitance (LC) circuits at a finite temperature T was considered and it was shown that the quantum mechanical zero-point fluctuations of both charge and current increase with upgoing T. Thermal field dynamics is used in the discussion.
Abstract: We consider the quantization of LC (inductance-capacitance) circuit at a finite temperature T as any practical circuits always produce Joule heat except for superconductivity. It is shown that the quantum mechanical zero-point fluctuations of both charge and current increase with upgoing T. Thermal field dynamics is used in our discussion.
61 citations
TL;DR: In this paper, a scheme for teleporting an unknown quantum state of many particles is proposed, which operates essentially by prearranging the sharing of an Einstein-Podolsky-Rosen-correlated pair of particles every time.
Abstract: A scheme for teleporting an unknown quantum state of many particles is proposed. The scheme operates essentially by prearranging the sharing of an Einstein-Podolsky-Rosen-correlated pair of particles every time. We show that after performing a series of Bell-state measurements and single-particle unitary transformations, the unknown state of many particles, which was destroyed at one place, can be reconstructed at another place. Our scheme is actually obtained by generalizing an earlier scheme of Bennett et al. [Phys. Rev. Lett. 70 (1993) 1895; 76 (1996) 722] known as quantum teleportation to the multiparticle case.
49 citations
TL;DR: In this article, the Sb2O3-doped TiO2 varistors were obtained by conventional ceramic processing and the 0.75 mol% Sb 2O399.25 mol% TiO 2 varistor has a nonlinear coefficient α = 7 and a minimum breakdown electrical field of 6 V/mm.
Abstract: The Sb2O3-doped TiO2 varistors were obtained by conventional ceramic processing. The 0.75 mol% Sb2O399.25 mol% TiO2 varistor has a nonlinear coefficient α = 7 and a minimum breakdown electrical field of 6 V/mm. The nonlinear electrical behaviour of TiO2Sb2O3 ceramics was explained by the introduction of defects in the crystal lattice that are responsible for the formation of Schottky potential barriers at grain boundaries.
37 citations
TL;DR: In this paper, the deformed relativistic Hartree theory (DRH) is solved both in coordinate space and in harmonic oscillator basis, and the results obtained from these two methods are compared in details.
Abstract: The deformed relativistic Hartree theory (DRH) is solved both in coordinate space (DRH-c) and in harmonic oscillator basis (DRH-o). Results obtained from these two methods are compared in details. The DRH-c and DRH-o calculations give similar total binding energies, deformation, level structures and radii for nitrogen isotopes, while their descriptions on the density distributions for drip-line nuclei are very different. The large spatial distributions of nucleon densities, which is crucial to understand a weakly bound system, can only be obtained by DRH-c calculations. This implies that the DRH theory should be solved in coordinate space in order to describe nuclei close to the drip line.
25 citations
TL;DR: In this article, the authors used the truncated Painleve analysis to obtain soliton solutions of the Nizhnik-Novikov-Vesselov equation, which is a special case of the soliton solution of the (2+1)-integrable model.
Abstract: Using the standard truncated Painleve analysis, we have obtained some new special types of soliton solutions of a (2+1)-dimensional integrable model, the Nizhnik-Novikov-Vesselov equation. Starting from the standard truncation approach in the Painleve analysis, one can obtain a Backlund transformation to find a new solution from a known one. Usually, one can obtain only a single solitary wave solution from the Backlund transformation related to the truncated Painleve analysis starting from the trivial vacuum solution. In this paper, we find some special types of the multisoliton solutions from the truncated Painleve analysis and the trivial vacuum solution.
24 citations
TL;DR: In this paper, the Raman tensor calculation demonstrates that both transverse-optical and longitudinal optical phonons in PbSe crystal are Raman active on BaF2-oriented surface.
Abstract: PbSe films were grown on (111)-oriented BaF2 substrates by using molecular beam epitaxy. High resolution x-ray diffraction characterization showed good crystalline quality of PbSe films. Both longitudinal optical phonon at 135 cm-1 and transverse optical phonon at 47.6 cm-1 were observed by Raman scattering measurements. The Raman tensor calculation demonstrates that both transverse-optical and longitudinal-optical (LO) phonons in PbSe crystal are Raman active on (111)-oriented surface. Furthermore, 2LO phonon at about 270 cm-1 and polaron at about 800 cm-1 in PbSe, were also observed. The observed Raman frequencies are in good agreement with theoretical calculations using point ion model.
24 citations
TL;DR: In this article, the role of the two system parameters α and K, governing the direction and strength of the kick, respectively, is investigated in a 1-dimensional kicked billiard model and its transport behavior is investigated.
Abstract: We study a classical 1-dimensional kicked billiard model and investigate its transport behavior. The roles played by the two system parameters α and K, governing the direction and strength of the kick, respectively, are found to be quite crucial. For the perturbations which are not strong, i.e. K < 1, we find that as the phase parameter α changes within its range of interest from -π/2 to π/2, the phase space is in turn characterized by the structure of a prevalently connected stochastic web (-π/2 ≤ α < 0), local stochastic webs surrounded by a stochastic sea (0 < α < π/2) and the global stochastic sea (α = π/2). Extensive numerical investigations also indicate that the system's transport behavior in the irregular regions of the phase space for K < 1 has a dependence on the system parameters and the transport coefficient D can be expressed as D ≈ D0(α)Kf(α). For strong kicks, i.e. K 1, the phase space is occupied by the stochastic sea, and the transport behavior of the system seems to be similar to that of the kicked rotor and independent of α.
22 citations
TL;DR: In this article, the Fourier transform infrared spectrometry (FTIR) spectra of SiO2 thin films are deliberated to reveal the structure change of siO2 and the mechanism of dielectric constant reduction after doping fluorine.
Abstract: Fluorine doped silicon dioxide (SiOF) thin films have been prepared by plasma enhanced chemical vapor deposition. The Fourier transform infrared spectrometry (FTIR) spectra of SiOF films are deliberated to reveal the structure change of SiO2 and the mechanism of dielectric constant reduction after doping fluorine. When F is doped in SiO2 films, the Si-O stretching absorption peak will have a blue-shift due to increase of the partial charge of the O atom. The FTIR spectra indicate that some Si-OH components in the thin film can be removed after doping fluorine. These changes reduce the ionic and orientational polarization, and result in the reduction in dielectric constant of the film. According to Gaussian fitting, it is found that the Si-F2 bonds will appear in the SiOF film with increase of the fluorine content. The Si-F2 structures are liable to react with water, and cause the same increase of absorbed moisture in the film.
22 citations
TL;DR: In this paper, a family of interesting exact solutions of the sine-Gordon equation are constructed, which seem to be some soliton, kink, and anti-kink ones respectively for the different choice of the spectrum, whereas due to the interaction between two traveling-waves they have some properties different from usual soliton and kink solutions.
Abstract: By using AKNS [Phys. Rev. Lett. 31 (1973) 125] system and introducing the wave function, a family of interesting exact solutions of the sine-Gordon equation are constructed. These solutions seem to be some soliton, kink, and anti-kink ones respectively for the different choice of the spectrum, whereas due to the interaction between two traveling-waves they have some properties different from usual soliton, kink, and anti-kink solutions.
21 citations
TL;DR: Based on a 2 × 2 mass matrix, the mixing angle of the axial vector states f1(1420) and f 1(1285) is determined to be 51.5°, and the theoretical results about the decay and production of the two states are presented as mentioned in this paper.
Abstract: Based on a 2 × 2 mass matrix, the mixing angle of the axial vector states f1(1420) and f1(1285) is determined to be 51.5°, and the theoretical results about the decay and production of the two states are presented. The theoretical results are in good agreement with the present experimental results, which suggests that f1(1420) can be assigned as the partner of f1(1285) in the 3P1 q nonet. We also suggest that the existence of f1(1510) needs further experimental confirmation.
TL;DR: In this article, the structural transformation in γ-Fe2O3 nanocrystals (about 10 nm) with dodecyl benzene sulfonic (DBS) coated is studied by using high-pressure energy dispersive x-ray diffraction of synchrotron radiation and high-resolution transmission electron microscopy (HRTEM).
Abstract: Structural transformation in γ-Fe2O3 nanocrystals (about 10 nm) with dodecyl benzene sulfonic (DBS) coated is studied by using high-pressure energy dispersive x-ray diffraction of synchrotron radiation and high-resolution transmission electron microscopy (HRTEM). Relative to the bulk crystal, the transition pressure showed a decrease while the compressibility increases significantly up to 375 (±9 GPa). HRTEM picture confirmed that there is surface cladding surrounding nanocrystals due to DBS, which formed new special boundaries between nanocrystals and should be different from the ordinary grain boundaries. The experimental results imply that the surface layers of γ-Fe2O3 nanocrystals have strong effect on the compressibility.
TL;DR: In this paper, a transmission-reflection-combined method is presented for measuring elastic velocities of rocks and minerals at elevated temperature and pressure, which resolves the problems of gradients of temperature/pressure existing in original sample assembly with a pyrophyllite cube.
Abstract: A transmission-reflection-combined new method is presented for measuring elastic velocities of rocks and minerals at elevated temperature and pressure, which resolves the problems of gradients of temperature and pressure existing in original sample assembly with a pyrophyllite cube. At room temperature and pressure up to 3 GPa, single-crystal quartz and eclogite were used to provide samples under test, respectively. The results of this work agree with the previous measurements very well within the error range. By the use of this new technique, more precise and reasonable data of elastic properties of rocks and minerals at elevated temperature and pressure can be achieved.
TL;DR: In this paper, lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (ne = 0.6 - 2.0 × 1019 m-3), toroidal magnetic field (Bt = 1.62 -2.0 T), and the experimental curves of current drive efficiency as a function of ne and Bt have also been obtained.
Abstract: Lower hybrid current drive experiments on the HT-7 device have been carried out by scanning the following parameters: central line averaged electron density (ne = 0.6 - 2.0 × 1019 m-3) and toroidal magnetic field (Bt = 1.62 - 2.0 T). The dependence of current drive efficiency on these parameters has been studied and the experimental curves of current drive efficiency as a function of ne and Bt have also been obtained. From these experimental results, it can be seen that current drive efficiency rises with the increase of toroidal magnetic field. As plasma density increases, the current drive efficiency first increases to a certain value, then gradually decreases, that is, there exists an optimized density regime where a better drive efficiency can be obtained. The analysis shows that the current drive efficiency is mainly affected by wave accessibility and impurity concentration, and the competition of these two factors determines the current drive efficiency.
TL;DR: In this paper, the Kukhtarev two-center model for photochromic doubly doped LiNbO3:Fe:Mn crystals is both numerically and analytically solved for the recording sensitivity and the fixed nonvolatile space charge field.
Abstract: The Kukhtarev two-center model for photochromic doubly doped LiNbO3:Fe:Mn crystals is both numerically and analytically solved for the recording sensitivity and the fixed nonvolatile space-charge field. An optimal prescription for material doping and oxidation/reduction processing is found, which requires that the crystal should be strongly oxidized together with a suitable Mn density with respect to the Fe density. Experiments performed with an oxidized crystal and a reduced crystal prove the prediction.
TL;DR: In this article, the effect of self-consistent dust-charge variation was investigated by employing reductive perturbation technique to derive dust-acoustic solitons in dusty plasmas with two-temperature isothermal ions.
Abstract: Dust-acoustic solitons in dusty plasmas with two-temperature isothermal ions are investigated by considering an effect of self-consistent dust-charge variation. Employing the reductive perturbation technique we derived dust-acoustic solitons. It is found that both rarefactive and compressive solitons exist and the approximate similarity law which holds in dust-charge-fluctuation plasma system with one-temperature ion does not survive in the present studied dusty plasma with two-temperature isothermal ions.
TL;DR: In this paper, the photoluminescence emission at about 520 nm from Eu2+ doped ZnS nanocrystals at room temperature was investigated by using photoluminance emission and excitation spectroscopy.
Abstract: Eu2+ doped ZnS nanocrystals exhibit new luminescence properties because of the enlarged energy gap of nanocrystalline ZnS host due to quantum confinement effects. Photoluminescence emission at about 520 nm from Eu2+ doped ZnS nanocrystals at room temperature is investigated by using photoluminescence emission and excitation spectroscopy. Such green emission with long lifetime (ms) is proposed to be a result of excitation, ionization, carriers recapture and recombination via Eu2+ centers in nanocrystalline ZnS host.
TL;DR: In this article, the quantum wavefunctions and corresponding energy levels of a RLC (Resistance-Inductance-Capacity) electric circuit are obtained by using canonical quantization method and unitary transformation from the classical equation of motion.
Abstract: The quantum wavefunctions and the corresponding energy levels of a RLC (Resistance-Inductance-Capacity) electric circuit are obtained by using canonical quantization method and unitary transformation from the classical equation of motion. The quantum fluctuations of charge and current in an arbitrary eigenstate of the system have also been given as well as the uncertainty relation. It is showed that even if at 0 K charge and current in the circuit exhibit quantum fluctuations, which originates from fluctuations of zero point vibrations of the system.
TL;DR: In this article, a constant pressure molecular dynamics simulation and the pair analysis technique have been performed to study the microstructural evolution of aluminium during rapid solidification, and the results may help us understand the microstructure of glass and its stability.
Abstract: Constant-pressure molecular dynamics simulation and the pair analysis technique have been performed to study the microstructural evolution of aluminium during rapid solidification. The microstructure characteristics of icosahedral ordering increase with decrease of the cooling rate, whereas the microstructure unit characteristics of hcp crystalline structure decrease. There are two kinds of microstructure units which are similar to those in the fcc crystal containing interstitialcies. These two kinds of microscopic units are nearly independent of the cooling rate. The microscopic structural unit characteristics of fcc crystalline structure do not depend on the cooling rate either. These results may help us understand the microstructure of glass and its stability.
TL;DR: In this paper, the optical transmission of one-dimensional Fibonacci-class quasiperiodic multilayers, which possess a mirror symmetry, was studied and it was shown that the transmission coefficient is unity for all studied sequences at the central wavelength λ = λ0.
Abstract: We have studied the optical transmission of one-dimensional Fibonacci-class quasiperiodic multilayers, which possess a mirror symmetry. We find that the transmission coefficient is unity for all studied sequences at the central wavelength λ = λ0, where λ0 = (1/4)nA(B)dA(B) with nA(B) and dA(B) being the index of refraction and thickness of two kinds of layers, respectively. Two-cycle or three-cycle has been found around λ = λ0, which is different from the features of the sequences without symmetric structure.
TL;DR: In this paper, the magnetization profiles of ferromagnetic Ising films in a transverse field were derived by the transfer matrix method, and a general nonlinear equation for phase transition temperatures was derived and then calculated.
Abstract: Within the framework of the mean field theory, we study the magnetization profiles of ferromagnetic Ising films in a transverse field. By the transfer matrix method, we first derive a general nonlinear equation for phase transition temperatures and then calculate the magnetization profiles of the system. The method proposed here can be applied to ferromagnetic films with arbitrary surface layer number, bulk layer number, exchange interaction constants and transverse fields.
TL;DR: In this article, the quantum fluctuations of charge and magnetic flux of a mesoscopic RLC circuit in a displaced squeezed Fock state were studied and it was shown that the fluctuations of magnetic flux do not depend on the displacement parameter and there exist squeezing effects between them.
Abstract: Starting from the equation of motion for a circuit including resistor, inductor and capacitor (RLC), we study the quantum fluctuations of charge and magnetic flux of a mesoscopic RLC circuit in a displaced squeezed Fock state. It is found that the fluctuations of charge and magnetic flux do not depend on the displacement parameter and there exist squeezing effects between them. We also show how to generate the displaced squeezed Fock state in the RLC circuit.
TL;DR: The double-well potential systems and a hybrid optical bistability device with liquid crystal have a relation to quartic maps with two equally high peaks as mentioned in this paper, and the star products for all doubly superstable kneading sequences in the knaving plane are presented, the generalized Feigenbaum's metric universalities such as scaling factors and convergent rates are obtained.
Abstract: The double-well potential systems and a hybrid optical bistability device with liquid crystal have a relation to quartic maps with two equally high peaks. The star products for all doubly superstable kneading sequences in the kneading plane are presented, the generalized Feigenbaum's metric universalities such as scaling factors {?C, ?D, ?E} and convergent rates {?a, ??, ?a,?} are obtained.
TL;DR: In this article, the results of a molecular dynamics simulation for CaSiO3 melt under an electric field were presented, where the two-body interaction potential was adopted in the simulation, with parameters chosen so that the calculated static structure is consistent with results of high temperature x-ray experiments.
Abstract: The results of a molecular dynamics (MD) simulation are presented for CaSiO3 melt under an electric field. The two-body interaction potential is adopted in the simulation, with parameters chosen so that the calculated static structure is consistent with results of high temperature x-ray experiments. It is found that the MD results for the heat capacity at constant volume, the self-diffusion coefficient and the electrical conductivity change greatly when the electric field is over 500 MV/m. Discussion is given on these results, together with the frequency-dependent electrical conductivity.
TL;DR: In this paper, nano-crystalline diamond films were deposited in a hot filament chemical vapor deposition system using CH4/H2 gas mixture, using various measurements such as field emission scanning electron microscopy, micro-Raman spectroscopy, x-ray photoelectron spectrograms, and transmission electron microscope for characterization.
Abstract: We have deposited nano-crystalline diamond films in a routine hot filament chemical vapor deposition system, using CH4/H2 gas mixture We used various measurements such as field emission scanning electron microscopy, micro-Raman spectroscopy, x-ray photoelectron spectroscopy, and transmission electron microscopy for characterization The result show that the films consist of a crystalline diamond phase with small grain sizes ranging from 20 to 100 nm
TL;DR: In this article, a bilayer heterojunction device was fabricated by using a novel oxadiazole derivative: 2, 2'-(2,5-thiophenediyl) bis (5-(4-methyl) phenyl-1,3,4-oxadiazoles) (T-OXD) as the electron-transporting layer (ETL) and a pyrazoline derivative: 1-phenyl-3-(dimethylamino)styryl-5-(p-(dimethyl)phenyl)pyrazoline (PDP
Abstract: The bilayer heterojunction devices were fabricated successfully by using a novel oxadiazole derivative: 2, 2'-(2,5-thiophenediyl) bis (5-(4-methyl) phenyl-1,3,4-oxadiazole) (T-OXD) as the electron-transporting layer (ETL) and a pyrazoline derivative:1-phenyl-3-(dimethylamino)styryl-5-(p-(dimethylamino) phenyl)pyrazoline (PDP) as the light-emitting layer and the hole-transporting layer. The emission at 500 nm was derived from PDP layer. In comparison with the bilayer device of tris (8-hydroxyquinoline) aluminum (Alq) as the ETL, the luminous efficiency of the PDP/T-OXD heterojunction device was enhanced by 104 times.
TL;DR: In this paper, the influence of thermal induced optical nonlinearities on Z-scan measurements with a nanosecond pulse laser is investigated theoretically, and the results demonstrate that thermal effect plays an important role in certain circumstance.
Abstract: The influence of thermally induced optical nonlinearities on Z-scan measurements with a nanosecond pulse laser is investigated theoretically. The results demonstrate that thermal effect plays an important role in certain circumstance. As an example, the optical nonlinearities of CS2 with an adjustable linear absorption coefficient which is used to alter the magnitude of thermally induced optical nonlinearities are analysed, and the results show that thermal effect even makes the change of the sign of optical nonlinearities.
TL;DR: In this paper, the binding energy of an exciton bound to an ionized donor impurity (D+,X) located st the center or the edge in GaAs-AlxGa1-xAs quantum wells is calculated variationally for the well width from 10 to 300 Angstrom by using a two-parameter wave function.
Abstract: The binding energy of an exciton bound to an ionized donor impurity (D+,X) located st the center or the edge in GaAs-AlxGa1-xAs quantum wells is calculated variationally for the well width from 10 to 300 Angstrom by using a two-parameter wave function, The theoretical results are discussed and compared with the previous experimental results.
TL;DR: In this article, the quantum entropic dynamics of the phonons and trapped ion were studied and the authors obtained a general evolution operator of the trapped ion system, which is the same as the one of the field in the Jaynes-Cummings model.
Abstract: By performing a unitary transformation, we transform the Hamiltonian of the trapped ion in any position of standing wave to that of the normal Jaynes-Cummings model in ionic bare basis and we obtain a general evolution operator of the trapped ion system. We study the quantum entropic dynamics of the phonons and trapped ion. Our results show that, when the trapped ion is located at the node of standing wave, the quantum entropic dynamics of phonons and trapped ion are the same as the one of the field in the Jaynes-Cummings model. When the trapped ion deviates from the node of standing wave, the entropies of the phonons and ion keep their maximum value except at the initial stage, and the phonons and trapped ion become extremely entangled.
TL;DR: In this article, the refractive index change induced by a focused incident beam with an additional incoherent uniform illumination in photovoltaic-photorefractive crystals under open-circuit condition has a saturable nonlinearity form.
Abstract: We show that the refractive index change induced by a focused incident beam with an additional incoherent uniform illumination in photovoltaic-photorefractive crystals under open-circuit condition has a saturable nonlinearity form. The incoherent uniform background illumination can be used to increase the effective dark irradiance. The formation time of the photovoltaic soliton can be decreased by keeping the intensity of the soliton at a higher value without over-saturation by use of the background illumination.