Modern Physics Letters B

This study employs precise, accurate, and efficient analytical and numerical techniques to obtain novel and accurate solitary wave solutions for the (2+1)-dimensional Ablowitz–Kaup–Newell–Segur (AKNS) equation. The Khater II (Khat II) method and extended cubic-B-spline (ECBS) scheme are utilized as recent computational and accurate numerical techniques, respectively, for investigating the AKNS equation and constructing highly precise solitary wave solutions. The stability characteristics of the obtained solutions are also analyzed to ensure their applicability. These solutions are characterized by their peak amplitudes, wave speeds, and widths. Through comparisons with previous numerical techniques, our proposed approach demonstrates superior effectiveness and reliability. The research is significant due to the application of the (2+1)-dimensional AKNS equation in modeling various physical phenomena, such as nonlinear optics, water waves, and plasma physics. The precise and efficient determination of solitary wave solutions not only enhances the understanding of these phenomena but also provides a valuable framework for practical applications. The results have substantial implications for comprehending complex wave dynamics in physical systems and serve as a valuable tool for further research and analysis in the field of wave dynamics.

The influence of shear deformation on the electronic and optical properties of the Al-doped arsenene has been investigated using the first-nature principle based on density general function theory. Within this study, the 5.882% doping concentration in the Al-doped arsenene makes it reasonably stable and the doping of Al atoms causes the arsenene to exhibit quasi-metallic properties. The combined energy calculations show that the structural stability of the Al-doped arsenene is not significantly affected by shear deformation. With increased shear deformation, the band gap of intrinsic arsenene reduces, and the band gap of the Al-doped arsenene similarly does. Optical properties analysis indicates that shear deformation redshifts both the absorption and reflection peaks of the doped system.

A theoretical analysis on the influence of photothermal effects on the photoconduction of one-dimensional (1D) carbyne nanostructures has been explored in this paper. It is found that the size dependence of photoconduction is a great benefit from the change of band structure and optical absorption, while the influence of photothermal effect on the photoconduction is mainly induced by the grain boundary scattering and transport properties. Moreover, the photoconduction increases as the incident power enhances with a $P_0^{\gamma }$ dependence and $\gamma$ is not only related to the illumination intensity but also modulated by the dimensions. Our predictions are consistent with the available evidence, which indicates that our model is crucial for the understanding of the physical mechanism on the photothermal effect of 1D carbyne nanostructures and for their potential applications in nanotechnologies.

The optical properties of bulk AuCu₃-type ordered superconducting binary compounds ScGa₃ and LuGa₃ have been experimentally investigated for the first time in the wide spectral range and explained in terms of the band structure. First-principles calculations of electronic densities of states and optical conductivities are performed within the framework of LSDA+U method using the LMTO-ASA software package. The measured dielectric functions spectra for both materials exhibit a strong absorption region above ∼ 1eV, which are in a reasonable agreement with the calculated metal-like energy structures of compounds. Features of quantum light absorption are discussed on the basis of a comparative analysis of experimental and theoretical spectra of interband optical conductivity. Plasma and relaxation frequencies of conduction electrons are determined.

The effect of surface roughness, magnetic field, and couple stress on the performance of secant slider bearing is studied in this paper. The effectiveness of the bearing is assessed by using a couple stress liquid as the lubricant in the process. Because of microstructural impacts, couple stress fluids have distinctive rheological characteristics. These features have the potential to make a major impact on the bearing’s performance. The novel aspect of this study is that the roughness of the secant slider is taken into consideration. The modified Reynolds equation is derived using Christensen’s stochastic theory for roughness. Here, both transverse and longitudinal roughness patterns are considered. The analytical solutions are obtained for steady-state pressure, load-carrying capacity, film stiffness, and damping coefficient. The results are presented for various parameters through graphs and tables. The combined effect of the magnetic field and couple stress is significant on bearing characteristics. It is noticed that the bearing features increase with the longitudinal roughness parameter, and the reverse phenomenon is observed with the transverse roughness parameter. When a transverse roughness pattern is assumed on a secant slider bearing, characteristics like pressure, load, stiffness of the film, and damping coefficient increase significantly.

Vegetable insulating oil, with advantages such as high safety and environmental friendliness, is a good substitute for traditional mineral oil. However, thermal failure is one of the important factors affecting the safe operation of oil-immersed electrical equipment. This study focuses on soybean vegetable oil as the research subject and establishes a simulation model for soybean insulating oil to investigate the influence of thermal stress at different temperatures ranging from 1000K to 2000K on system decomposition and gas generation characteristics. The results indicate that, under elevated temperatures, the decomposition of soybean vegetable insulating oil predominantly occurs through decarboxylation reactions, leading to the generation of CO₂ and hydrocarbon radicals. The hydrocarbon radicals further decompose and react with other species, resulting in the formation of characteristic gases. It was observed that CO₂ and C₂H₄ serve as stable thermal decomposition by-products. Increasing temperatures significantly enhance the generation rates of various characteristic products and broaden the variety of such products. For instance, H₂ and CH₄ are characteristic gases produced at different temperature ranges. Studying the decomposition and gas generation characteristics of vegetable insulating oil under thermal stress holds crucial significance for transformer design and operation.

In thermophotovoltaic (TPV) systems, it is crucial that the selective emitters can tailor emission spectrum to match the bandgap of photovoltaic (PV) cells and largely enhance the system efficiency. In this work, a metamaterial emitter based on the metal-insulator-metal (MIM) structure is proposed to obtain the high energy conversion efficiencies. The geometric parameters of MIM emitter have been investigated to obtain an excellent radiation spectrum of emitter composed of W and HfO₂. The excellent emission performance of MIM emitter is attributed to the excitation of surface plasmon polariton (SPP) and cavity resonance, and the structure of MIM emitter is insensitive for different polarization modes. The 21 material combinations of MIM emitters have been screened to obtain the optimal emitter matching GaSb and InGaAsSb cells. This work identifies the crucial role of structure and materials into the emitter of a TPV system. In the evaluation of MIM emitter and TPV System, when the operating temperature of emitter increases from 1400K to 2000K, the system efficiency of optimal W/HfO₂/W MIM emitter increases from 20.26% to 30.41%, while the output electric power increases from 3.59kW/m² to 42.48kW/m². The phenomenon indicates that the MIM emitter with the optimal material combinations and geometric parameters can significantly improve the matching degree with GaSb and InGaAsSb cells. Our results will be helpful to expand the optimization scope of metamaterial emitters in TPV systems.

We show that the temperature-dependent superconducting order parameter and related superconducting properties (in particular, the temperature dependences of specific heat, superfluid density and related London penetration depth) of high-$T_c$ cuprates are fundamentally different from those of conventional superconductors and cannot be understood within the existing theories based on the Bardeen–Cooper–Schrieffer (BCS)-type condensation of weakly bound Cooper pairs into a superfluid Fermi-liquid and on the usual Bose–Einstein condensation (BEC) of bosonic Cooper pairs. We examine the validity of an alternative approach to the unconventional superconductivity in high-$T_c$ cuprates and establish that these materials exhibiting a $\lambda$-like superconducting transition at the critical temperature $T_c$ are similar to the superfluid ⁴He and are also superfluid Bose systems. We argue that the doped high-$T_c$ cuprates, from underdoped to overdoped regime, are unconventional (bosonic) superconductors and the tightly bound (polaronic) Cooper pairs in these polar materials behave like composite bosons just like ⁴He atoms and condense into a Bose superfluid at $T_c$. We identify the superconducting order parameter ${\mathrm{\Delta }}_{\mathrm{\text{SC}}}$ in underdoped and optimally doped cuprates as the coherence parameter ${\mathrm{\Delta }}_B$ of bosonic Cooper pairs, which appears just below $T_c$ and has a kink-like temperature dependence near the characteristic temperature $T_c^{\ast }<T_c$. We find that the $\lambda$-like specific heat anomaly in high-$T_c$ cuprates near $T_c$ predicted by the theory of Bose-liquid superconductivity is similar to that observed both in superfluid ⁴He near $T_{\lambda }$ and in Hg-based cuprate superconductor HgBa₂Ca₂Cu₃O₈ near $T_c\simeq 132$K. We demonstrate that in high-$T_c$ superconductor YBa₂Cu₃${\mathrm{\text{O}}}_{6.97}$ the superfluid density ${\rho }_s$ exhibits distinctly different temperature dependences in the temperature ranges $0\le T\le T_c^{\ast }$ and $T_c^{\ast }<T<T_c$. In this superconductor, a pronounced anomaly in ${\rho }_s(T)$ exists near $T_c^{\ast }\simeq 0.4T_c$ and the temperature dependence of ${\lambda }_L^2(0)/{\lambda }_L^2(T)$ below $T_c^{\ast }$ deviates downwards from the high-temperature behavior. Our results for the normalized superfluid density ${\rho }_s(T)/{\rho }_s(0)={\lambda }_L^2(0)/{\lambda }_L^2(T)$ are in good agreement with the experimental data on the temperature dependence of ${\lambda }_L^2(0)/{\lambda }_L^2(T)$ in YBa₂Cu₃${\mathrm{\text{O}}}_{6.97}$. The anomalous temperature dependences of specific heat and superfluid density observed in Hg- and Y-based high-$T_c$ superconductors are clear signatures of Bose-liquid superconductivity.

The robustness of complex networks to various kinds of attacks that could trigger cascading failures has attracted increasing attention. Most existing studies fail to consider that the cost to attack each network component (node or edge) may be unequal. Therefore, in this paper, we explore the network robustness to cascaded attacks based on heterogeneous costs. We introduce an attack cost model with both cost-sensitive and budget-constraint parameters. On this basis, three attack strategies are considered, including hub strategy, average degree strategy, and leaf strategy. Their cascaded attack effects are compared by considering the load local preferential redistribution rule. Both the fraction of failed nodes and the value of a new robustness metric, i.e. the budget-constraint threshold, are monitored in different complex networks. Numerical experiments indicate that as the attack cost changes from homogeneity to heterogeneity, the performance of the classic hub strategy decreases gradually. For the situation of weak heterogeneity of attack cost of each node, leaf strategy achieves the maximum attack performance gradually. Moreover, the budget, network structure, and robustness metrics may all affect the selection of the optimal attack strategy.

In the 21st century, understanding the mechanism of high-temperature superconductivity has emerged as a pinnacle achievement in condensed matter physics, capturing the lifelong interest of numerous physicists. This paper endeavors to offer a theoretical elucidation for this mechanism, advancing the broader field of physics. Recognizing that high-temperature superconductivity is an aspect of condensed matter physics — underpinned by Maxwell’s classical electromagnetic theory — we turn to theoretical mechanics and field theory, which are foundational perspectives in the contemporary scientific era. By framing Maxwell’s classical electromagnetic theory within the context of theoretical mechanics and field theory, this paper not only sheds light on the mechanism of high-temperature superconductivity but also recasts Maxwell’s theory within a purer theoretical mechanics and field theory domain. This represents a paradigmatic shift and cognitive transformation in physics. Furthermore, leveraging this theoretical mechanics and field theory interpretation of electromagnetic phenomena, we discern that electromagnetic phenomena can be more aptly explained without resorting to the concepts of charges and electric fields, leading to a reinterpretation of Coulomb’s law. We propose that protons and electrons might exist as entities devoid of charge-specific attributes and negate the possibility of a strongly correlated particle system within them.

Layered metal composites have been widely used in various industries fields because of their excellent properties and are responsible for mechanical behavior of materials. This paper focuses on analyzing the deformation mechanism of the (110) interface under different loading states by MD. The results show that there are two yield points in the stress–strain curve under both Z- and Y-axis loading states. The first yield is the nucleation of dislocations at the interface, meantime the slip of dislocations and the extension of stacking faults begin at the Al layer. The second one, the dislocation passes through the interface, nucleates and emits toward the Cu layer at the interface, leading to a stress mutation. It is worth noting that during the stable rheological stage, the deformation mechanisms vary under different loading directions. Under Y-axis tensile loading, the phase transformation of FCC–HCP is present due to the interaction of dislocation movement and stacking fault. On the contrary, there are two twin paths A and B, improving the strength, during Z-axis compression loading. For other loading modes, there are three zones, namely the elastic stage, the release of energy, and strain hardening and dynamic softening. The interface plays the role of nucleation, annihilation and penetration of dislocations, and this interface-dislocation mechanism is reflected in the whole stage of plastic deformation. The results have an insight into the design and control in heterointerface.

In this paper, a numerical framework for modelling multiphase flows with interface correction is proposed. In original Volume-of-Fluid method, the interface smearing may appear since the interface profile deviates from its equilibrium state, especially in the simulations of complex interface deformation. To solve this problem, a novel correction step is introduced into the procedure after solving the volume fraction transport equation, and this step just works on the region of phase interface. The difference between the current method and the previous work is that the correction coefficient can be adjusted adaptively with the gradient of normal velocity at the interface, which is strongly correlated to the intensity of interface smearing and changes with the computational time and interface position. The validation computations are performed for bubble deformation (initial shapes of two-dimensional four-lobed-star and three-dimensional (3D) box with holes), bubble rising in a channel and Rayleigh–Taylor instability problems (Reynolds number of 100 and 1000). The obtained results show that the unphysical phenomenon of interface smearing is suppressed effectively, and the interface sharpness is improved greatly by the present method. In addition, the mass of bubble deformation by the original method will decrease by 13.3%. While these results obtained by the present method are in good agreement with the analytical solutions or published data.

Today’s need of the growing industries is to get better products with long life which depends upon the production processes. This requires enhanced thermal properties of the fluid as well as the components surrounding to it. Therefore, this study reveals the flow of several water-based nanofluids past an expanding sheet. Oxide nanoparticles, such as Al₂O₃ and CuO, are considered in the base liquid water to show their behavior on the flow phenomena. Further, dissipative heat properties due to magnetization, i.e. Joule and viscous dissipation enrich the study. The novelty of this study is the consideration of KKL “(Koo–Kleinstreuer–Li) correlation” for the conductivity and viscosity plays its important role in which the influence of Brownian activity is vital. The utilization of similarity rules is beneficial for the transformation of the governing equations into non-dimensional form. Further, the shooting-based Runge–Kutta technique is useful for the solution of these set of equations. The characterization of diversified components likely the particle concentration, magnetic and buoyancy parameter on the velocity distribution along with the Eckert number, and thermal radiation on the energy profile is obtained and deliberated briefly.

This study emphasizes the dual exposition of the impact of convective condition and the significant effects of magnetic field, heat source and velocity slip on hybrid nanofluid flow over the exponentially shrinking sheet. The hybrid nanofluid is regarded as a contemporary variety of nanofluid; consequently, it is utilized to enhance the efficiency of heat transfer. By applying the Tiwari–Das model, the key objective of the current research is to investigate the impact of involving factors Biot number, Eckert number, volume fraction, magnetohydrodynamic (MHD), slip and suction on the temperature and velocity profiles. In addition, the Nusselt number and skin friction variations have been explored against the suction effect on the solid volume fraction of copper ${\varphi }_2\in$ [1–3%] and the Biot number $\mathrm{\text{Bi}}\in$ [1–3%]. The nonlinear partial differential equations are converted to a set of an ordinary differential equations by incorporating exponential similarity vectors. Eventually, ordinary differential equations are rectified utilizing MATLAB bvp4c solver. The results demonstrate the presence of dual exposition for suction with varying values of copper volume fraction and the Biot number. The heat transmission rate is observed to escalate in both cases as the strength of the Biot and Eckert numbers intensifies in the range of 1–3%. In summary, the results show that duality and non-unique solutions occur in the aiding flow situation when the suction $S\ge S_{\mathrm{\text{ci}}}$, while there is no flow and unique solutions of hybrid nanofluid feasible when $S<S_{\mathrm{\text{ci}}}$.

The lack of a bandgap in stanene severely limits its outstanding characteristics in optoelectronic devices. Using first-principles calculations, we systematically investigate the effects of full hydrogenation and shear deformation on the electronic structure and optical properties of stanene. Hydrogenation exerts a remarkable impact on electronic structure of stanene, enabling surface state transition from quasi-metallic to semiconducting. Shear degrades the structural stability of full-hydrogenated stanene (FHstanene). FHstanene exhibits a tunable bandgap of 1.327eV, which can be further reduced to 0.719eV through shear deformation. The presence of spin-orbit coupling (SOC) induces band splitting in FHstanene. The maximum optical absorption of FHstanene occurs at 291nm, while the reflectance peak is observed at 449nm. The variation in bandgap due to deformation results in a redshift in the absorption coefficient and reflectance, and shear deformation increases the reflectance of FHstanene. These findings broaden the application prospects of stanene in novel nano-optoelectronic devices.