Modern Physics Letters B

In this paper, we investigate the pairwise quantum correlations in a two-qubit anisotropic Heisenberg model under the interplay of Calogero–Moser (CM) and Dzyaloshinsky–Moriya (DM) interactions in the presence of the homogeneous and inhomogeneous magnetic fields. We employ, respectively, the logarithmic negativity and local quantum uncertainty (LQU) to characterize the degree of entanglement and the amount of quantum correlations between the two parties of the considered system in equilibrium with a thermal reservoir. We analyze and compare the behaviors of the two quantum correlation quantifiers in the thermal state of the chain spin system and we discuss how relative distance between spins, equilibrium temperature, DM interaction coupling parameter and the external magnetic fields strengths influence the variations of both quantum correlation measures in such system.

Skin cancer is a common human malignant tumor and melanoma is one of the most fatal diseases in skin cancer. There exists a high degree of visual similarity between melanoma and non-melanoma. In addition, the acquisition and labeling of skin cancer images need relevant medical knowledge, therefore, it is difficult to obtain natural images. These problems make it difficult to distinguish between melanoma and non-melanoma. How to extract the high-dimensional features of skin cancer images is the main problem to improve the classification performance of skin cancer images. For this purpose, we propose a new computer-aided classification system with a two-dimensional (2D) multifractal detrended fluctuation analysis (MF-DCCA) method and classifier combination. The proposed 2D MF-DCCA is expanded by the 2D MF-DFA and we aim to change the distribution of the generalized Hurst exponents calculated by the original 2D MF-DFA, making the image features represented by the generalized Hurst exponents calculated by 2D MF-DCCA are more significant. Therefore, we take the generalized Hurst exponents calculated by the two methods into the classifier and evaluate their classification performance. The classification metrics, such as Accuracy (Acc), Sensitivity (Sen), and Specificity (Spe) of two classifiers, show that the features extracted by MF-DCCA are better than those by MF-DFA. In addition, among the two classifiers such as the SVM and k-NN, the k-NN performs best in Acc and Spe with $97.72\%$ and $97.72\%$, respectively. The k-NN performs better than SVM in the classification Sen with $98.94\%\pm 0.1213$.

Critical nodes of complex networks are pivotal for effective information propagation. Several centrality methods have been presented to identify critical nodes relied on the relationships between node and its neighbors, which indicates that the interaction between them will account for determining the importance of nodes. In this paper, a novel ranking method based on the defined similarity coefficient is proposed. The main thought of the proposed method is that the importance of nodes being linked to the local structural similarity between node and its neighbors. By quantifying the distinction between the node’s local structure information, a similarity matrix of the entire network is constructed first. Further, the similarity coefficient of node is defined by taking into account the interaction relationships between nodes and the local structural attribute of complex networks. Finally, a novel method, named Extended Similarity Coefficient Ranking Method (ESCRM), is proposed to determine the influentiality of node based on its neighbors’ information. We perform extensive experiments on ten real-world datasets to comprehensively estimate the performance of the ESCRM and other ten representative centralities. The experimental results demonstrate that under the Susceptible-Infected-Recovered (SIR) model, the ESCRM outperforms the other centralities on identifying critical nodes, and as a relatively efficient ranking method can provide better performance.

For increasing the cooling performance within the system with one circular hot wall, combinations of nanotechnology and Kelvin force have been utilized. Iron oxide with fraction of 0.04 has been added to water and properties were estimated according to homogenous model. Appearance of wire near the middle of circular wall generates space-dependent Kelvin force which acts like gravity force and boosts the migration of ferrofluid. To gain the solution, CVFEM was applied to measure the values of scalars. Before employment of numerical approach, the equations become simplified with defining the vorticity formulation. Utilizing FHD makes the fluid move faster inside the domain and more effective collision with walls happens. Nu elevates about 108.05% by applying FHD when $\mathrm{\text{Ra}}=\mathrm{\text{1e3}}$. When ${\mathrm{\text{Mn}}}_F=0$ and 4e3, imposing greater buoyancy forces offers augmentation of Nu about 11.54% and 0.01%. Utilizing ferrofluid instead of H₂O makes Nu to rise around 14.15%.

The multiple exp-function technique, as an extension to Hirota’s perturbation algorithm, is employed to find N-soliton solutions of the 3D Vakhnenko–Parkes (3D-VP) equation. This is a straightforward and effective alternative method. Consequently, one- two- and three-soliton solutions besides the front wave solutions and their wave numbers are obtained, which are completely distinct from the other published literature. 3D and density plots were investigated via the help of the Maple package program by suitably choosing the free parameters in the solutions. Further, the physical meaning for these solutions is clarified. We mention that the propagation of high-frequency waves in a relaxing medium can be investigated by discussing the dynamical behavior of the obtained solutions for the 3D-VP equation.

In this work, MoS₂ was successfully deposited on Ni foam (NF) by a simple one-step electrochemical deposition method. MoS₂ were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectrum (XPS) and energy dispersive spectrometer (EDS). XRD and FESEM results show that MoS₂ is an amorphous film structure. The electrochemical properties of the MoS₂ electrode have been studied in detail via cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopic (EIS) technology, respectively. The MoS₂/NF binder-free electrode provides a special capacitance of 210 F/g at a constant discharge current density of 1 A/g. When the current density increases five times, the specific capacitance can still maintain 51.74% of the initial capacitance. In addition, after 1000 cycles at 3 A/g, the capacitance retention of the MoS₂ electrode still retained 79.4%.

Starting from a discrete spectral problem, two new integrable differential-difference hierarchies are presented and their Lax pairs are given, respectively. The first hierarchy is related to the relativistic Toda lattice equation. Darboux transformations for the first systems in the two hierarchies are derived, respectively, accordingly their explicit solutions are obtained. By selecting appropriate parameters, we can see the phenomena of soliton fission or soliton fusion.

In this paper, a special class of exact solutions of the coupled higher-dimensional Klein–Gordon–Zakharov (KGZ) equation with power law nonlinearities is constructed explicitly by separation transformation method. One merit of this work is that when the dimension is larger than one, there is an arbitrary function $f(\varsigma )$, which is used to search for more general exact solutions of the coupled higher-dimensional KGZ equation. As a result, the Jacobi elliptic function solutions and soliton solutions with free parameters are derived, which lead to rich localized nonlinear structures of the coupled higher-dimensional KGZ equation with power law nonlinearities.

In this paper, we study the asymptotic stability of the monotone decreasing kink profile solitary wave solutions of the generalized Gardner equation with dissipative term. Firstly, we obtain the estimation of the first-order and second-order derivatives for monotone decreasing kink profile solitary wave solutions, then by using anti-derivative strategy, with the help of prior estimate and Young inequality, we overcome the difficulties caused by two higher-order nonlinear terms of the equation in the estimation, and prove the asymptotic stability of monotone decreasing kink profile solitary wave solution in the sense of $L^{\infty }$ norm.

The development of micropump is directly related to the popularization and application of microfluidic systems. Recently, microfluidic systems have more urgent requirements for stable operation and simple structure of micropumps. For these purposes, a novel micro steam jet pump which uses planar induction heating to evaporate the initial fluid is presented. This new micropump could generate continuous flow with merits of no moving parts, stable operation and easy integration. A negative pressure is formed flowed with high-speed flow of vapor in the chamber to pump and eject liquid, and then realize continuous pumping. The working chamber of the micropump is calculated with aerodynamic function, and the simulation analysis is carried on with COMSOL Multiphysics 5.5. By changing key working parameters, appropriate working conditions are adopted with simulation analysis. When the primary vapor temperature is 403.15 K, the inlet width of the tapered section of the mixing chamber is 0.4 mm and the outlet width of the diffuser is 0.5 mm, the mingling and enhancing pressure performance of the micro steam jet pump is better. The optimization of design and simulation involved in this paper provided a good guidance for the design and experimental study of the micro steam jet pump.

We show that two-mode squeezed vacuum-like states may be engineered in the Bohm–Madelung formalism by adequately choosing the phase of the wave function. The difference between our wave function and the one of the squeezed vacuum states is given precisely by the phase we selected. We would like to stress that the engineering of two-mode vacuum states is possible due to the existence of the Bohm potential, and it is relevant because of its potential use in the propagation of optical fields, where it may render a variety of applications in optics. The approach to generate non-classical states, namely, two-mode squeezed states of a quantum mechanical system is one of the first applications of the Madelung–Bohm formalism.

Based on the principle of linearized stability proposed by Lyapunov, we investigate the robustness of Majorana zero-energy state (MZES), which plays an important role in topological quantum computation. We show that the MZES is not robust enough against the external perturbations, because mathematically it is critically stable instead of being asymptotically stable, and only the states with asymptotic stability can be regarded as robust, therefore, the MZES cannot be used to carry quantum information in topological quantum computation. Our study is different from previous works that usually make the numerical tests by some special perturbations, whereas our analytical derivation is suitable for arbitrary perturbations. As an example, we demonstrate this by the stability analysis of MZES in the spin-orbit-coupled semiconductor/superconductor junction.