Huang Zu-Qia

Dust-Acoustic Solitons in Dusty Plasma with Two-Temperature Ions

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.

Frequency catastrophe and co-existing attractors in a cell Ca2+ nonlinear oscillation model with time delay

Frequency catastrophe is found in a cell Ca2+ nonlinear oscillation model with time delay. The relation of the frequency transition to the time delay is studied by numerical simulations and theoretical analysis. There is a range of parameters in which two kinds of attractors with great frequency differences co-exist in the system. Along with parameter changes, a critical phenomenon occurs and the oscillation frequency changes greatly. This mechanism helps us to deepen the understanding of the complex dynamics of delay systems and might be of some meaning in cell signalling.

FLUX IN THE CASE OF GAUSSIAN WHITE NOISES

The transport of a spatially periodic system driven by additive and multiplicative Gaussian white noises (between which there is a correlation function) is investigated. The probability current (flux) shows .that the correlation function between the additive and multiplicative noises, and the spatial asymmetry are ingredients for the flux of particles. It is a new phenomenon that the correlation function between the additive and multiplicative noises can cause transport.

Time-Correlation Function for Periodically-Forced Nonlinear Stochastic System*

The equilibrium time-correlation function for a general cosine-forced stochastic system are calculated respectively by the perturbation theory and the linear response theory. The results obtained by the two theories are basically identical. By calculation we find that it has two terms. One is the original time-correlation function (in the case when the external signal does not exist). The other is caused by the perturbing external signal. The two terms have the same relaxation time, and the latter has oscillator behavior.

SUPERCONDUCTING JUNCTIONS IN THE CASE OF CORRELATED SYMMETRIC NOISES

We study two models for Josephson junctions, i.e., a Gaussian white noise model and a symmetric dichotomous noises model. In this study we find that the correlated symmetric noises can produce a net voltage. This phenomenon is due to the correlation between the additive and the multiplicative noises. We show some characteristic features for this phenomenon: the net voltage is always negative and has a peak value when the strength of the additive noises varies for the former model (or when the strengths of the noises vary for the latter model). The results provide a theoretical foundation for reducing the net voltage caused by the correlated symmetric noises.

ON A CLASS OF EXACT SOLUTIONS OF THE BOLTZMANN EQUATION

A class of spatially dependent exact solutions of the Boltzmann equation for a gas of monatomic Maxwell molecules is obtained and discussed. The similarity solution describing a gas uniformly flying away proposed by Bobylev1 is included in this class as a special case.

Third-Harmonic Generated in EH32 Mode of a Gas-Filled WavegUide by fs Laser Pulses

In this paper it is reported for the first time that the third harmonic generated in EH32 mode of a gas-filled waveguide by fs pulses has higher generation efficiency. The new finding contrasts with the experiment in [C.G. Durfee III, S. Backus, M.M. Murnane, and H.C. Kapteyn, Opt. Lett. 22 (1997) 1565]. Some possible factors, which produce the contradiction, are discussed briefly.

Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

A numerical simulation of the backward Raman amplifying in plasma

This paper describe a numerical simulation method for the interaction between laser pulses and low density plasmas based on hydrodynamic approximation. We investigate Backward Raman Amplifying (BRA) experiments and their variants. The numerical results are in good agreement with experiments.

Theoretical Description of the Third Order Parametric Wave Mixing in a Gas-Filled Capillary of Femto-Second Laser Pulse*

The theoretical signal-pressure curves are calculated from approximate analytical solutions of the coupled equations describing the third order parametric wave mixing in a gas-filled capillary of femto-second laser pulses. The comparison with the corresponding experimental curves suggests that the following three factors exert important influences on the degree of fitting between the theoretical and experimental results: the walk-off, the phase modulation, and the third order harmonic of idler pulse.