International Journal of Modern Physics B

For reinforcement, the photochromic field and the cooperation between the theoretical and experimental branches of physics, the computational, theoretical artificial neural networks (CTANNs) and the resilient back propagation (R${}_{\mathrm{\text{prop}}}$) training algorithm were used to model optical characterizations of casting (Admantan-Fulgide) thin films with different concentrations. The simulated values of ANN are in good agreement with the experimental data. The model was also used to predict values, which were not included in the training. The high precision of the model has been constructed. Moreover, the concentration dependence of both the energy gaps and Urbach’s tail were, also tested. The capability of the technique to simulate the experimental information with best accuracy and the foretelling of some concentrations which is not involved in the experimental data recommends it to dominate the modeling technique in casting (Admantan-Fulgide) thin films.

Weighted folded hypercube is an charming variance of the famous hypercube and is superior to the weighted hypercube in many criteria. We mainly study the scaling of network coherence for the weighted folded hypercube that is controlled by a weight factor. Network coherence quantifies the steady-state variance of these fluctuations, and it can be regarded as a measure of robustness of the consensus process to the additive noise. If networks with small steady-state variance have better network coherence, it can be regarded as more robust to noise than networks with low coherence. We firstly calculate the spectra of weighted folded hypercube and obtain the leading terms of network coherence that are quantified as the sum and square sum of reciprocals of all nonzero Laplacian eigenvalues. Finally, the results show that network coherence depends on iterations and weight factor. Meanwhile, with larger order, the scatings of the first- and second-order network coherence of weighted folded hypercube decrease with the increasing of weight factor.

In this paper, we presented the fabrication and testing of a new type of stretchable interconnections based on horseshoe shape metal nanowires. The stretchable interconnections could serve for stretchable electronics which are widely used in the field of tactile sensor, surgical devices, intelligent manufacturing and so on. The significant advantage of the stretchable interconnections is that excellent stretchability and outstanding conductivity are obtained simultaneously. The proposed horseshoe shape stretchable interconnections were fabricated by embedding silver nanowires (AgNWs) into the surface of a polydimethylsiloxane (PDMS) thin film. The results from the stretching tests have demonstrated that the stretchable interconnections has a stable resistance (around 15$\mathrm{\Omega }$) after repeated stretching and release. Moreover, the resistance increment in the 30% stretched state after fifty stretching cycles is only 138% of the initial value. With the good conductivity and stability during stretching, the stretchable interconnections developed in this paper are applicable to stretchable electronic devices.

We study the overdamped Brownian dynamics of a particle in a sawtooth potential along with a temporal asymmetric driving force. We observe that in the deterministic limit, the transport coherence which is determined by a dimensionless quantity, called Peclet number Pe, is quite high under certain circumstances. For all the regime of parameter space of this model, Pe in our model shows similar features of current like Stokes efficiency. Diffusion as a function of driving amplitude shows a nonmonotonic behavior and results a minimum exactly at which the current shows a maximum. Unlike the previously studied models, Pe in our model shows a peaking behavior with temperature. Moreover, the diffusion shows a nonlinear dependence of temperature in the long-time limit and it is sensitive to the potential asymmetry parameter.

Effects of site preference, phase stability and brittle versus ductile behaviors of W, Mo, La and Ce in TiAl have been investigated by using the first-principles calculations. The results show that transition elements W and Mo can effectively stabilize B2 phase except rare earth elements La or Ce. Elastic modulus show that the ductility can be improved for ternary elements addition and there is a plastic transition from intrinsic brittleness to intrinsic ductility with W and Mo addition due to phase transition. The competitive mechanisms between the opening of microcracks and dislocation emission show the increased ductility is mainly due to the energetic dislocation but suppressed cracks. Finally, electronic density of states and charge density show that weakened covalent interactions of TiAl for W, Mo, La and Ce addition are the essential reasons for the transformation from brittleness to ductility.

We present new complexiton solutions to the (2 + 1)-dimensional asymmetric Nizhnik–Novikov–Veselov (aNNV) equation by application of the Hirota direct method and the linear superposition principle. We first find hyperbolic function solutions to the corresponding bilinear equation and consequently derive the so-called complexitons. In particular, we construct nonsingular complexiton solutions from positive complexiton solutions of the bilinear form of the nonlinear equation. Finally, we give some illustrative examples and a few concluding remarks.

A double-stranded DNA molecule subject to a perpendicular gating electric field and a small mechanical strain exhibits a negative differential resistance (NDR) in its current–voltage (I–V) characteristics. Using an advanced two-dimensional tight-binding model including hopping integrals for the next nearest-neighbors, we implement perturbative strain- and tilted angle-dependent DNA helix conformation in conjunction with the theories of Slater–Koster and linear elasticity. The degree of NDR can be tuned by adjusting the tilt angle and mechanical strain of the DNA. This effect arises because of a surface charge distribution near the contacts due to the normal component of the electric field and structural change of the DNA molecule due to the strain. It is shown that enhancement of NDR peak current and a large peak-to-valley ratio of NDR are achieved by an increase of the tilt angle and stretching strain. Finally, a series of step-like current jumps without NDR features are exhibited in the weak DNA-lead coupling regime. This disappearance of NDR stems from the fact that reduced conduction through metal electrodes with a sufficiently small tunneling rate compensates the current drop.

In this paper, an air sector network (ASN) model is established based on the airspace of Chinese mainland. Meanwhile, the ASN is a weighted graph whose nodes are sectors, and its edge weight is the flights between sectors. In addition, a node ranking algorithm is proposed according to the variation coefficient method (VCM). Then, the topological structure of the ASN is analyzed by the complex network theory, simultaneously, the key sectors are ranked through the proposed VCM. The results indicate that the ASN has heterogeneous and assortativity structure characteristics to a certain extent. Finally, the effectiveness of the proposed VCM centrality measure is verified by the susceptible-infected-removed (SIR) model and Kendall’s tau coefficient. Results show that the VCM centrality method is applicable and effective.

Urban bus transit is a major mode of transportation in modern cities and plays an important role in mitigating the traffic pressure in urban road networks. We used smartcard data collected by three-million bus passengers in Shenzhen, a major southern city of China, to study the statistical properties and dynamics of bus passenger flows. In this study, the recorded passenger flows were cross-grained into each 1 km × 1 km square grids to avoid large flow variations at a single bus station. The temporal and spatial patterns of passenger flows were analyzed and a machine learning-based model for passenger flow prediction was generated.

The mixed spin-1/2 and spin-1 Blume–Capel model is studied with randomly alternated coordination numbers (CN) on the Bethe lattice (BL) by utilizing the exact recursion relations. Two different CNs are randomly distributed on the BL by using the standard–random (SR) approach. It is observed that this model presents first-order phase transitions and tricritical points for variations of CNs 3 and 4, even if these behaviors are not displayed for the regular mixed-spin on the BL. The phase diagrams are mapped by obtaining the phase transition temperatures of the first- and second-order on several planes.

Weakly first-order or nearly second-order phase transitions occurring in metal–organic frameworks (MOFs), particularly in DMAKCr and perovskite HyFe, are studied under the mean field model by using the observed data from the literature. In this work, mainly thermal and magnetic properties among various physical properties which have been reported in the literature for those MOFs are studied by the mean field theory. By expanding the free energy in terms of the magnetization (order parameter), the excess heat capacity ($\mathrm{\Delta }$C${}_P$) and entropy ($\mathrm{\Delta }$S), latent heat (L), magnetization (M) and the inverse susceptibility (${\chi }^{-1}$) are calculated as a function of temperature close to the weakly first-order phase transition within the Landau phenomenological model which is fitted to the experimental data from the literature for C${}_P$ (DMAKCr and perovskite HyFe) and for magnetization M (HyFe).

Our predictions of the excess heat capacity ($\mathrm{\Delta }$C${}_P$) and entropy ($\mathrm{\Delta }$S) agree below T${}_c$ with the observed data within the temperature intervals studied for DMAKCr and perovskite HyFe. From our predictions, we find that magnetization decreases continuously whereas the inverse susceptibility decreases linearly with increasing temperature toward the transition temperature in those MOFs as expected for a weakly first-order transition from the mean field model.

Most illegal Ponzi schemes are ultimately out of control and lead to systemic financial risk. Risk education and precaution are similar to mass random immunization of epidemic spreading. In this study, the effect of random immunization strategy is evaluated based on the potential-investor–divestor (PID) spreading model in both homo- and inhomogeneous social networks. Fund flux function and system balance function are formulated. The zero point of system balance is used as the collapse point. The peak value of balance, the total number of investors involved and the total amount of principal involved are defined to compare the immunization effects in various scenarios. Mathematical derivation and numerical simulation show that the random immunization takes effect by postponing the peak position of the system balance as well as suppressing the peak values of the system balance. This kind of positive effect helps reduce the scheme’s scale of total number of investors involved and total amount of principal involved. The random immunization is more powerful towards the schemes with small spreading rate than those with medium and high spreading rates. Hence, it is suitable for the concentrated regulation on a large amount of small scale and slow spreading schemes in bulk.

In this paper, we calculate ab initially the phonon dispersion relationship of the superconductor LaFeAsO and investigate a main property in the superconductor, the oxygen isotope effect. Based on this phonon dispersion relationship, we find the fact that an important reason of the oxygen isotope effect is connected with the phonon. This result agrees well with the experimental data where the power index of the oxygen isotope effect in the superconductor LaFeAsO is small.

The modified spin-wave theory is used to investigate the one-dimensional Heisenberg ferromagnet with the nearest-neighbor (NN) and next-nearest-neighbor (NNN) exchange anisotropies. The ground-state and low-temperature properties of the system are studied within the self-consistent method. It is found that the effect of the NN anisotropy on the thermodynamic quantities is stronger than that of the NNN anisotropy in the low-temperature region. The anisotropy dependence behaviors (such as the power, exponential and linear laws) are obtained for the position and the height of the maximum of the specific heat and its coefficient, as well as the susceptibility coefficient. The specific heat and its coefficient both display the low-temperature double maxima which are induced by the anisotropies and the NNN interaction. In the very low temperatures the specific heat and the susceptibility behave severally as T${}^{1/4}$ and T${}^{-4/3}$ at the critical point J₂/J₁ = −0.25, where J₁ and J₂ are the NN and NNN interactions, respectively.