Wang Ming-Jun

GENERALIZED SYNCHRONIZATION OF FRACTIONAL ORDER CHAOTIC SYSTEMS

In the paper, generalized chaotic synchronization of a class of fractional order systems is studied. Based on the stability theory of linear fractional order systems, a generalized synchronization scheme is presented, and theoretical analysis is provided to verify its feasibility. The proposed method can realize generalized synchronization not only of fractional order systems with same dimension, but also of systems with different dimensions. Besides, the function relation of generalized synchronization can be linear or nonlinear. Numerical simulations show the effectiveness of the scheme.

Projective synchronization of a complex network with different fractional order chaos nodes

Based on the stability theory of the linear fractional order system, projective synchronization of a complex network is studied in the paper, and the coupling functions of the connected nodes are identified. With this method, the projective synchronization of the network with different fractional order chaos nodes can be achieved, besides, the number of the nodes does not affect the stability of the whole network. In the numerical simulations, the chaotic fractional order Lu system, Liu system and Coullet system are chosen as examples to show the effectiveness of the scheme.

Dynamic analysis of a new chaotic system with fractional order and its generalized projective synchronization

Based on the stability theory of the fractional order system, the dynamic behaviours of a new fractional order system are investigated theoretically. The lowest order we found to have chaos in the new three-dimensional system is 2.46, and the period routes to chaos in the new fractional order system are also found. The effectiveness of our analysis results is further verified by numerical simulations and positive largest Lyapunov exponent. Furthermore, a nonlinear feedback controller is designed to achieve the generalized projective synchronization of the fractional order chaotic system, and its validity is proved by Laplace transformation theory.

Anisotropic scattering for a magnetized cold plasma sphere

The transformation of parameter tensors for anisotropic medium in different coordinate systems is derived. The electric field for a magnetized cold plasma sphere and the general expression of scattering field from anisotropic target are obtained. The functional relations of differential scattering cross section and the RCS for the magnetized plasma sphere are presented. Simulation results are in agree with that in the literatures, which shows the method used and results obtained are correct and the results provide a theoretical base for anisotropic target identification etc.

Scintillation of partially coherent Gaussian-Schell model beam propagation in slant atmospheric turbulence considering inner- and outer-scale effects

Based on the modified Rytov theory and the international telecommunication union-radio (ITU-R) slant atmospheric structure constant model, the uniform scintillation index of partially coherent Gaussian—Schell model (GSM) beam propagation in the slant path is derived from weak- to strong-turbulence regions considering inner- and outer-scale effects. The effects of wavelength of beams and inner- and outer-scale of turbulence on scintillation are analyzed numerically. Comparison between the scintillation of GSM beams under the von Karman spectrum and that of beams under the modified Hill spectrum is made. The results obtained show that the scintillation index obtained under the von Karman spectrum is smaller than that under the modified Hill spectrum. This study can find theory bases for the experiments of the partially coherent GSM beam propagation through atmospheric turbulence.

Microwave propagation in charged sand particles

Based on the forward scattering amplitude function for charged sand particle under the Rayleigh approximation, the calculation model of microwave attenuation due to charged sand particles is given in terms of equisized distribution and exponential distribution. The attenuation is calculated and analyzed. The results show that the attenuation with charged sand is larger than without regard to charges on the sand surface, and the more concentrative the surface charges on sand particles are, the greater are the influence on microwave attenuation. The attenuation due to the sand particles following exponential distribution is greater than that due to the sand particles for the equisized distribution.

Electric fields inside and outside an anisotropic dielectric sphere

Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electromagnetic theory. The theoretical expressions are consistent with those in the literature. The inside electric field, the outside electric field and the angle between their directions are derived in detail. Numerical simulations show that the direction of the outside field influences the magnitude of the inside field, while the dielectric constant tensor greatly affects its direction.

Partially coherent Gaussian—Schell model pulse beam propagation in slant atmospheric turbulence

Based on the extended Huygens—Fresnel principle, a two-frequency, two-point cross-spectral density function of partially coherent Gaussian—Schell model pulse (GSMP) beam propagation in slant atmospheric turbulence is derived. Using the Markov approximation method and on the assumption that (ω1 − ω2)/(ω1 + ω2) ≤ 1, the theory obtained is valid for turbulence of any strength and can be applied to narrow-band signals. The expressions for average beam intensity, the beam size, and the two-frequency complex degree of coherence of a GSMP beam are obtained. The numerical results are presented, and the effects of the frequency, initial pulse width, initial beam radius, zenith angle, and outer scales on the complex degree of coherence are discussed. This study provides a better understanding of the second-order statistics of a GSMP beam propagating through atmospheric turbulence in the space-frequency domain.

Rayleigh Scattering for An Electromagnetic Anisotropic Medium Sphere

Based on the scales theory of electromagnetic waves, the analytical expression of electrical fields inside an anisotropic medium sphere is studied. Differential scattering cross section and radar cross section (RCS) for an anisotropic spherical target are presented. The correctness of the obtained results is tested. The simulation results show that the scattering of an anisotropic sphere has the property of a dipole radiation under the condition of Rayleigh scattering. The larger the dielectric constant is, the stronger the dipole scattering is. Anisotropy in magnetism only has an effect on differential RCS. These results provide a theoretical base for the identification of anisotropic targets.

The laser radar Doppler spectrum of moving conical target in its spaced orbit observed by ground-based station

Utilizing the characteristics of laser Doppler spectrum of rotating conical target in target coordinate system and combining with a hypothetical spaced orbit data and transformed relationships between space target, ground-based observation and geocentric coordinate system, the model on the laser radar Doppler spectrum of moving conical target in its orbit observed by ground-based station is presented in this paper. Three applied cases are detaily calculated and analyzed that the lidar normalized power of moving conical target observed by ground-based station is changed with the time of orbit and the Doppler frequency shift in different dimensions and roughness of conical target and different ground-based observed directions. The calculated results are shown that the dimension and roughness of orbited conical target and different ground-based observed directions have influnce on their laser Doppler spectrum. The rules of the lidar normalized power changed with the time of orbit and the Doppler frequency shift is periodically fluctuated for any spaced conical targets. As the rotation speed is constant, the dimension of conic target is bigger, Doppler frequency shift is higher. The roughess of the conic surface is bigger, the fluctuatations of lidar normalized power changed with the time of orbit and the Doppler frequency shift is strongger. So our works are based on further developed to theoretically study on all kinds of spased complex targets in their orbits and furth given a technological support for laser radar observing spased complex targets with micro-motion and distinguishing true/false targets in their orbits on gound-based station.