Density fluctuations in intermediate-energy heavy-ion collisions

Within the framework of the isospin-dependent quantum molecular dynamics model,we simulate^(129)Xe+^(119)Sn collisions in an incident energy range of 20 to 190MeV/nucleon and discuss the liquid-gas phase transition with density fluctuations.For comparison,we also extract the effective Fisher parameter τ_(eff),multiplicity of intermediate-mass fragments(IMFs),and information entropy.It is found that the Fisher parameter and maximum information entropy of collisions have peak values at E_(beam)=50-80 MeV/nucleon.In addition,the maximum multiplicity of IMFs has a plateau around 70 MeV/nucleon.For higher-order density moments in a larger central region of[-5,5]^(3) fm^(3) in the collision system,a maximum plateau also appears as function of beam energy at energies exceeding 70 MeV/nucleon.These observables,which are consistent with each other,indicate a liquid-gas phase transition around 70 MeV/nucleon for the^(129)Xe+^(119)Sn system.

Upper bound for the time derivative of entropy for a stochastic dynamical system with double singularities driven by non-Gaussian noise

A stochastic dynamical system with double singularities driven by non-Gaussian noise is investigated. The Fokker Plank equation of the system is obtained through the path-integral approach and the method of transformation. Based on the definition of Shannon＇s information entropy and the Schwartz inequality principle, the upper bound for the time derivative of entropy is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculations can be used to interpret the effects of the system dissipative parameter, the system singularity strength parameter, the noise correlation time and the noise deviation parameter on the upper bound.

Edge detection of magnetic tile cracks,based on wavelet

In order to extract the defect edge information on the magnetic tile surface with low contrast and textured background,an edge detection algorithm based on image weighted information entropy and wavelet modulus maxima is proposed.At first,a new Butterworth high pass filter(BHPF) with adaptive cutoff frequency is produced,because the clarity and complexity of the textured background are described by the weighted information entropy of the image gradient variance quantitatively,and the filter can change its parameters through matching the non-linear relationship between the information entropy and the cutoff frequency.And then,the best decomposition scale is obtained by the level determination function to prevent edge information from missing.At last,edge points are got by double threshold after obtaining the wavelet modulus maxima,and then the edge image is linked by the edge points to ensure the edge continuity and veracity.Experiment results indicate that the proposed algorithm outperforms the conventional Canny and Sobel algorithm,and the edge detection algorithm can also detect other defects,and lays the foundation for defecting auto- recognition.