International Journal of Modern Physics B

In this paper, rotation properties of suspended particles under an external rotating electric field (EREF) are investigated. Based on the re-distribution of surface-induced charges on moving particles, the torque exerting on particles by EREF is derived analytically. Furthermore, for the sol suspended in Newtonian fluid, the angular velocity of the rotating particle is formulated by the EREF and the dielectric constants of the particle and matrix. The result shows that the angular velocity of particles depends on the angular velocity of EREF, and is proportional to the square of EREF strength. The maximum angular velocity of rotating particles is reached if the angular velocity of EREF is equal to the reciprocal of the relaxation time of the induced charge.

Understanding energy transfer between working fluid and vapor is a critical issue in absorption refrigeration and thermophysics for the aim of intensifying heat conversion. However, it is difficult to achieve by experimental measurements due to the difficulty in catching the detailed and accurate modeling information, e.g., specific working fluid, and its underlying molecular mechanism. In order to study the evaporation and boiling behavior of refrigerant mixture from the microscopic point of view, the nanofilm consisting of different working fluids, with the evaporation model of R32/R1234ze (E) on metal wall, was established by utilizing molecular dynamics (MD) method. The effect of different mole ratios, i.e., pure R32, 3:1, 1:1, 1:3, pure R1234ze (E), on the evaporation and boiling behavior of mixtures was analyzed. The results show that the probability of explosive boiling decreases with the decrease of R32 molecular mole ratios. Thus, in turn, the performance of refrigerant mixture is observed to be better than that of pure refrigerant. Insights from this simulation research could provide an effective reference for the MD interactions and have potential benefit in developing efficient and sustainable processes for industries to minimize the chemical usage and environmental damage.

Since the concept of memristor was proposed, the memristor, as the fourth-generation electronic component, has attracted great attention from researchers. Memristors can be used not only for nonvolatile memory but also to mimic the behavior of nervous system. The inherent nonlinearity of memristor makes it valuable in nonlinear circuits. Since it is still difficult to realize the commercial application of memristors at present, designing suitable memristor models can play a guiding role in practical application. This work proposes a novel memristor model with a time-delay state variable. The proposed memristor cannot only generate pinched hysteresis loop under periodic signal excitation, but also can generate chaotic current or even hyperchaotic current under DC voltage. The nonlinear dynamics of the proposed time-delay memristor are studied by phase portraits, bifurcation diagram and Lyapunov exponents. Furthermore, the proposed memristor is used in the HR neuron model to study neuronal electrical activities with electromagnetic induction. Multiple firing patterns of the memristive neuron can be generated such as periodic, bursting and chaotic. Finally, the memristor emulator circuit and the HR neuron model circuit are designed and simulated by Pspice.

The electronic transport behavior of a sulflower molecule sandwiched between metal leads by S atom connecting apex Au or Ag atoms was investigated using a first-principles study by current-voltage characteristics, transmission spectrum and local density of states. Negative differential resistance (NDR) effect which originates from Coulomb blockade driven by bias was obtained. We also found that the differential conductance can be modulated by the metal leads with different work functions, which promise the potential applications in molecular devices in the future.

In this paper, we use the improved modified extended tanh-function method to obtain exact solutions for the nonlinear longitudinal wave equation in magneto-electro-elastic circular rod. With the aid of this method, we get many exact solutions like bright and singular solitons, rational, singular periodic, hyperbolic, Jacobi elliptic function and exponential solutions. Moreover, the two-dimensional and the three-dimensional graphs of some solutions are plotted for knowing the physical interpretation.

Micropolar fluid flow studied in this paper is influenced by microstructural slip. The flow is directed by a scheme of Partial Differential Equalities. These Partial Differential Equalities are then converted to nonlinear set of Ordinary Differential Equalities via boundary layer conversions. MATLAB bvp4c built in code is taken into account to resolve the leading set of ODEs, along with the initial-boundary settings. Hydro dynamical and thermal boundary layer outlines are considered and deliberated and the results are confirmed by linking with available literature in the classical case. Microstructural slip effects are shown on the Nusselt number and skin-friction coefficient. This model can better predict the effects and characteristics of rotational slip. Specifically, it is predicted from the tabular and graphical results that the rotational slip affects the boundary layer thickness when second-order translational slip disappears. It is important to mention that augmenting the standards of Prandtl number and radiation constraint declines the fluid temperature in the nonappearance and existence of microstructural slip. Moreover, increasing the values of magnetic parameter enhances the fluid temperature in presence as well as in absence of microstructural slip.

In this work, an exact renormalization group treatment of honeycomb lattice leading to an exact relation between the coupling strengths of the honeycomb and the triangular lattices is presented. Using the honeycomb and the triangular duality relation, the critical coupling values of honeycomb and triangular lattices are calculated exactly by the simultaneous solution of the renormalized relation and the duality relation, without using the so-called star-triangular transformation. Apparently, the obtained coupling relation is unique. It not only takes place the role of the star triangular relation, but it is also the only exact relation obtained from renormalization group theory other than the 1D Ising chain. An exact pair correlation function expression relating the nearest neighbors and the next nearest neighbor correlation functions are also obtained for the honeycomb lattice. Utilizing this correlation relation, an exact expression of the correlation length of the honeycomb lattice is calculated analytically for the coupling constant values less than the critical value in the realm of the scaling theory. The critical exponents $\nu$ and $\alpha$ are also calculated as $\nu =1$ and $\alpha =0$.

Complex network is now widely used in a series of disciplines such as biology, physics, mathematics, sociology and so on. In this paper, we construct the stock price trend network based on the knowledge of complex network, and then propose a method based on information entropy to divide the stock network into some communities, that is, a gathering study of stock price trend. We construct time series networks for each stock in Chinese A-share market based on time series network model, and then use these networks to divide the stock market into communities. We find that the average trend of stocks in the same community is the same as the trend of market value weighting, but the average trend of stocks in different communities is quite different and the sequence correlation is low. This conclusion shows that stocks in the same community share the same price trend, while the stock trend in different communities varies. This paper is a successful application of complex network and information entropy in stock trend analysis, which mainly includes two contributions. First, the success of the visibility graph algorithm provides a new perspective for enriching stock price trend modeling. Second, our conclusion proves that the clustering based on information entropy theory is effective, which provides a new method for further research on stock price trend, portfolio construction and stock return prediction.

This papers presents new exact analytical solutions of a generalized Ito equation having three nonlinear terms, third- and fifth-order derivative forms that model the dynamics of traveling waves in nonlinear dispersive systems. With the help of Riccati equation method, we obtain different kinds of exact traveling wave solutions containing dark, singular, trigonometric, rational and other form of waves solutions that are more general than classical ones existing in the literature. Despite the originality of the new results obtained, the method used here is very efficient, powerful and can be extended to other types of nonlinear equations and more. Moreover, the behaviors of traveling waves solutions are portrayed graphically by selecting suitable values for the physical parameters.

In this paper, we study the (3+1)-dimensional Burger system which is considered in soliton theory and generated by considering the Hirota bilinear operators. The bilinear frame to the Burger system by using the multi-dimensional Bell polynomials is constructed. Also, based on the binary Bäcklund transformations, the generalized Bell polynomials are written. We retrieve some novel exact analytical solutions, containing interaction between lump and two kink wave solutions, interaction between lump and periodic wave solutions, interaction between stripe and periodic solutions, breather wave solutions, cross-kink wave solutions, interaction between kink and periodic wave solutions, multi-wave solutions, and finally solitary wave solutions for the (3+1)-dimensional Burger system by Maple symbolic computations. The required conditions of the analyticity and positivity of the solutions can be easily achieved by taking special choices of the involved parameters. The main ingredients for this scheme are to recover the Hirota trilinear forms and their generalized equivalences.