Zhun-Zhi Jin

Growing networks with mixed attachment mechanisms

Networks grow and evolve when new nodes and links are added in. There are two methods to add the links: uniform attachment and preferential attachment. We take account of the addition of links with mixed attachment between uniform attachment and preferential attachment in proportion. By using numerical simulations and analysis based on a continuum theory, we obtain that the degree distribution P(k) has an extended power-law form P(k) ~ (k + k0)−γ. When the number of edges k of a node is much larger than a certain value k0, the degree distribution reduces to the power-law form P(k) ~ k−γ; and when k is much smaller than k0, the degree distribution degenerates into the exponential form . It has been found that degree distribution possesses this extended power-law form for many real networks, such as the movie actor network, the citation network of scientific papers and diverse protein interaction networks.

Influence of external field on diffusion-limited aggregation

Abstract The influence of external electric field on diffusion-limited aggregation (DLA) has been investigated by computer simulations. When the parameter λ increases from 0 to ∞, the morphology of aggregates changes from pure DLA to chain-like pattern gradually, where λ stands for the relative strength of field-induced dipolar interaction to thermal energy. The structure transition is the transition between a prototype disorder structure and a relative order one in essence. The reason of the transition is the interaction controlling systems changes from thermal force to field-induced dipolar interactions with λ rising.

Application of a probability model for relaxation to the dielectric and -relaxation of amorphous polyethylene terephthalate

A probability model (PM) developed recently, which is an alternative to the conventional Havriliak-Negami (HN) dispersion function for polymer systems, is applied for the first time to the study of the dielectric alpha- and beta-relaxation of amorphous polyethylene terephthalate (PET). It has been found that the temperature dependence of the maxima of the imaginary part of the dielectric function and of the half-width of the distribution in the PM of the alpha-relaxation exhibit Vogel-Fulcher-type temperature behaviour; the temperature dependence of the maxima of the imaginary part of the dielectric function of the beta ation is proportional to the ratio of the gauche content to the trans content of the ethylene glycol linkages in PET. Finally, the mechanisms of the alpha- and beta-relaxation are elucidated concisely.

Metal-nonmetal transition of fluid Cs along the liquid-vapour coexistence curve

Abstract The conductivity of expanded cesium along the liquid–vapour coexistence curve has been obtained by a three-component plasma model. The present work has concluded that the critical point of the liquid–vapour transition does not coincide with that of the metal–nonmetal transition of fluid Cs.

Calculated infrared and Raman spectra of P2O5 glass

Abstract The vibrational spectrum and structure of P 2 O 5 glass are calculated by the ab initio method with the STO-3G basis set. The cluster model PO 4 H 3 is used. The calculated results show that in P 2 O 5 glass each P atom is surrounded almost tetrahedrally by three bridging O atoms and one double-bonded O atom. The calculated frequencies are in good agreement with experimental data.

Extended DDA model: deposition, diffusion and aggregation with a power-law adsorption

Abstract The deposition, diffusion and aggregation (DDA) on surfaces with a power-law adsorption has been studied by Monte Carlo simulations. The model incorporates four elementary processes including deposition, diffusion, adsorption, and aggregation. When the correlation parameter α increases from 0 to ∞, the patterns change from site percolations to DDA clusters. The fractal dimension increases too. It shows that there is a clustering transition from a weakly correlated distribution of particles to a strongly correlated one.

Particle–cluster aggregation by randomness and directive correlation of particle motion

Abstract A particle–cluster aggregation model is presented, in which particle motion is controlled by randomness and directive correlation. The directive correlation means that the walking direction of the particle at next step relates to the moving direction at previous step. The influence of competition between randomness and directive correlation of particle motion on aggregation is investigated by Monte Carlo simulations.

Short-time dynamics behavior at the gas–liquid critical point

Abstract The dynamic relaxation process for the two dimension fluid at the critical point was studied, by using the constant pressure and constant temperature (NPT) molecular dynamics (MD). The system was initially at the state of very high temperature and of the density little higher than the critical density, and then it was quenched to the state of the critical temperature and critical pressure. The initial increase of the density was observed. The new dynamic exponent θ has been obtained and it manifests the universal short-time dynamic behavior also exists in the fluid phase.

Epidemic spreading in percolation worlds

Abstract Epidemic spreading in percolation worlds has been investigated by Monte Carlo simulations, based on a correlated percolation model. It is found that the spreading behavior is greatly influenced by the spreading worlds. When the correlation changes from the weak limit to a strong one, the pattern consisting of sick individuals converts from the pattern of site percolation to that of Leath percolation in a percolation world. Correspondingly, the fractal dimension varies from the dimension of the random pattern to that of dense growth morphology. The critical correlation exponent α c = d w , where d w is the fractal dimension of the percolation world. Furthermore, the critical behavior of epidemic spreading is obviously affected by the spreading world also. The threshold of pathogenic ratio s c =1 (for uniform world) and 0.593 (for the critical percolation one), respectively, in the strong correlation limit.

Are Guggenheim formulae and Landau theory still applicable to expanded liquid metals

In the present work, we have found that Guggenheim formulae are still applicable to the liquid-vapor coexistence curves of expanded fluid metals only by adjusting their coefficients rather than exponents. In addition, the equation of state of expanded liquid cesium has been derived based on Landau theory of continuous phase transitions including the sixth-order term of the order parameter. Both the equation of state and the coexistence curves obtained are in good agreement with experimental data