Modern Physics Letters B最新文献

The photogalvanic effect (PGE) can produce a photocurrent independent of a p–n junction or bias voltage, but the resulting photocurrent is usually very small. An appropriate lateral heterojunction can effectively enhance PGE. Here, we studied the PGE of a monolayer (ML) Janus MoSSe-CrSSe lateral heterojunction through ab initio quantum transport simulation. Compared with that of a homogeneous material, PGE is enhanced due to the reduced symmetry of the lateral heterojunction, and the maximum increase ratio in the photocurrent is more than two orders of magnitude greater than that of the homogeneous ML MoSSe and CrSSe photodetectors. A peak maximum photocurrent of 13.85 a${}_0^2$/photon and high polarization sensitivity with a maximum extinction ratio of 308 are obtained for the ML MoSSe-CrSSe lateral heterojunction. These favorable properties indicate that the MoSSe-CrSSe lateral heterojunction is a promising candidate for photodetectors.

Globally, infectious diseases pose a significant threat. Notable cases include influenza, Hepatitis B and HIV. COVID-19, caused by the coronavirus, has been the subject of recent discussion due to its great transmissibility. This study explores the Susceptible–Infectious–Recovered (SIR) epidemic model, explaining several analytical approaches to comprehend the nonlinear incident rates and geographic dispersion. The model investigates phenomena such as M-shaped solitons, homoclinic breather-like solitons, lump waves (LWs), lump solution (LS) with one or two kinks, rogue waves (RWs), periodic waves (PWs) and periodic cross-kink waves. These solutions aid in understanding the disease spread and informing containment strategies by identifying optimal outbreak control methods. This work studies localized wave solutions in nonlinear wave equations, known as soliton solutions including the LS. RWs are characterized by unexpectedly large amplitude and rapid profile changes, drawing attention for their erratic features. PWs exhibit periodic repetitions over time and space. Besides, some type of solitons with special waveforms are the periodic cross-kink, M-shaped and homoclinic breather-like solitons. Graphical representation visualizes the behavior of these effective waves, providing insights into virus spread in specific regions over time. SIR models help identify optimal strategies for controlling outbreaks. The work adds to our understanding of epidemic dynamics by illuminating how the movement of susceptible and infected individuals affects the spread of disease.

This study delves into the realm of optical soliton solutions within the intricate framework of highly dispersive couplers integrated with optical metamaterials featuring a parabolic law nonlinear refractive index. Employing the extended auxiliary equation method, the investigation systematically unveils various soliton solutions, including dark solitons, bright solitons, singular solitons, and a distinctive amalgamation of bright and singular solitons. The results illuminate the diverse dynamics of solitons in these complex systems, offering crucial insights into the interplay among dispersion, nonlinearity, and metamaterial characteristics. Beyond enhancing the theoretical understanding of soliton behavior in optical metamaterial couplers, the findings hold practical significance by potentially influencing the design and optimization of optical communication devices and systems.

Based on the first-principles study, the adsorption and electron transfer properties of Li atom at different sites of SnS₂ monolayer, SnS₂@Graphene 2D-nanocomposite are analyzed. The differential charge density and density of states (DOS) analysis show that the graphene substrate as an electron donor can change the 2D-nanocomposite from a semiconductor to a metal, and reduce the adsorption energy of Li atom by decreasing the charge transferring from Li atom to SnS₂. This indicates that graphene substrate is beneficial for improving the performance of SnS₂@Graphene. Meanwhile, the Li atoms tend not to cluster on the SnS₂@Graphene 2D-nanocomposite, which is useful to prolong the lifespan of the SnS₂@Graphene. The functionality of graphene in SnS₂@Graphene 2D-nanocomposite is proved by other electron donor substrates, such as a two-H-atom model and a Sn (111) substrate model. All the results indicate that the graphene, as an electron donor in SnS₂@Graphene 2D-nanocomposite, plays a key role in improving the performance of SnS₂ in rechargeable lithium batteries.

Nanofluids are the fluid suspensions in nanoparticles. A considerable enhancement in their features is less nanoparticle concentrations. Various studies on nanofluids focused on representing their performance with respect to the functions — here enhancing straight heat transfer was critical, like that in nuclear reactors, transportation, different industrial settings, biology, food and electronics. Hence, this consideration analyzes the utilization of the novel mathematical method, called the bvp4c method by viscous heat energy research in Buongiorno-modeled nanoliquid confined by the apt permeable plate along with slip mechanism. The thermophoresis and Brownian dispersion affects are again assumed. This transfer of solutal and thermal energy was dependent on the appreciable effect on heat source, variable chemical reactions and nonlinear thermal radiation. The dimensional model of partial differential equations (PDEs), applied to precise related applications, had been adapted into ordinary differential equations (ODEs). This modified Nusselt number decreases with increasing viscous heating, thermal radiation, thermophoresis parameter and Brownian motion, always it rises due to increasing temperature ratio parameter. The validation of the outcomes was attained with past solutions by free convectional flow and non-magnetic research. There are many functions in petroleum industries and engineering like electroplating, chemical processing of substantial metals and solar water heaters.

This work aims to examine the entropy production, heat transport, and dynamics of the unsteady thin film magnetohydrodynamic (MHD) flow of a nanofluid composed of alumina (Al₂O₃) and water. The fluid flow is seen to pass over an inclined sheet, taking into account the effects of buoyancy force, viscous dissipation, and joule heating. The system of partial differential equations (PDEs) is optimized under the boundary layer assumptions. Appropriate transformations are used to convert the governing partial differential equations (PDEs) and boundary conditions into dimensionless forms. Using MATLAB’s bvp4c code and a local non-similarity technique with up to second-degree truncation, we can obtain the findings of the enhanced model. The effect of multi-shape Al₂O₃ nanoparticles on flow, heat, and entropy-generating features is also investigated after the calculated results have been successfully aligned with published data. Mixed convection, nanoparticle volume percent, inclination angle, magnetic field intensity, mass suction, Eckert number, and Biot number are only a few of the governing parameters whose effects are graphically shown for selected values. As a result, the local Nusselt number and skin friction coefficient may be calculated. The skin friction and Nusselt number profiles exhibit a decreasing trend as the values of nanoparticle volume fraction ($\varphi$) magnetic $(M)$ and unsteadiness (A) increase toward mixed convection ($\delta$). On the other hand, Nusselt number profile increases with increasing values of mass suction parameter $(S)$ The profiles of entropy generation and Bejan number show an upsurge as the values of the magnetic parameter $(M)$ and Brinkman number (Br) increase. Conversely, the entropy generation reduces with an increase in the temperature difference parameter $(\mathrm{\Omega })$ and Bejan number increases.

Bismuth oxychloride (BiOCl)/silver (Ag)/tungsten oxide (WO₃) nanocomposite was produced by laser ablation to enhance photocatalytic performance. The ternary nanocomposite showed a superior photocatalytic activity for methylene blue (MB) degradation under visible light compared to pure BiOCl and BiOCl/Ag with degradation up to 74%, 62%, and 52 %, respectively. The addition of Ag improved the dispersibility of BiOCl and WO₃, which reduced the recombination of electron–hole pairs and can be responsible for higher photocatalytic activity.

This paper deals with the soliton solutions for beam movement within a multimode optical fiber featuring a parabolic index shape. It is considered that a Two-Dimensional Nonlinear Schrödinger Equation (2D-NLSE) with an instantaneous Kerr nonlinearity of the kind can represent the beam dynamics. Nonlinear Multimode Optical Fibers (MMFs) of this kind are gaining popularity because they provide novel approaches to control the spectral, temporal, and spatial characteristics of ultrashort light pulses. We gain the optical soliton solutions for the nonlinear evolution beam dynamics using the Jacobi Elliptic Function Expansion (JEFE) method. The exact analytical solution of Nonlinear Partial Differential Equations (NLPDEs) can be achieved with wide application using the effective JEFE approach. These solutions are obtained in the form of dark, bright, combined dark–bright, complex combo, periodic, and plane wave solutions. Additional solutions for Jacobi elliptic functions, encompassing both single and dual function solutions, have been acquired. This approach is based on Jacobi elliptic functions, which will provide us the exact soliton solutions to nonlinear problems. Additionally, we will analyze the Modulation Instability (MI) for the underlying model. Moreover, we show the physical behavior of the beam propagation in a multimode optical fiber the three-dimensional, two-dimensional, and their corresponding contour plots are dispatched using the different values of parameters.

Alcohol abuse is a substantial cause of various health and societal issues, as well as a significant factor in global disease. Once alcohol is consumed in the gastrointestinal tract, it undergoes metabolism in the liver and lungs. In this investigation, the nonlinear deterministic and stochastic differential frameworks are analyzed numerically to predict the dynamic evolution of the virus in the drinker alcohol model. The framework for apprehending drinking patterns is categorized into three distinct groups: the susceptible population, risk drinkers, and moderate drinkers. The approximate solution for each population group is determined by exhaustively creating scenarios that vary the probability ratio of infection in susceptible individuals who do not consume alcohol, the increasing rate of alcohol consumption, the rate at which individuals transition from acute to chronic drinking categories, the rate at which new non-drinking consumers are attracted, the death rate of the population, the ratio affecting the rate of sociability in heavy drinkers, and the overall population rate. The Euler–Maruyama approach for the stochastic framework and the Adams method for the deterministic framework are utilized, respectively, to determine the solutions of the alcohol drinker model. This study compares deterministic and stochastic frameworks to underscore their distinct characteristics and efficiency, achieved through comprehensive simulations and in-depth analysis of the numerical outcomes.

Colloidal crystals formed with attractive interactions are used for in-situ observations of homogeneous nucleation processes in density-matched dispersion. We found globular and plate-like polycrystalline clusters stably suspended in the dispersion. Both clusters rotated randomly and moved freely with suspending in the dispersion. They were probably formed through homogeneous nucleation processes.