Modern Physics Letters B

Researchers are working on perovskites for photovoltaic applications due to their low cost and excellent power conversion efficiency. Our investigation has focused on analyzing the effects of hydrostatic strain on the structural, electronic, optical and thermoelectric properties of CsSnBr₃. The calculated structural properties and enthalpy of formation imply that these structures are stable under different strain conditions. Our investigation shows that the CsSnBr₃ compound is a direct semiconductor with an electronic band gap of 1.272eV, which can be tuned from 0.604eV to 1.823eV under different strain conditions. As the compressive strain increases, the light absorption spectrum of CsSnBr₃ undergoes a red shift, causing a prolongation of the light absorption edge. The thermoelectric properties show that CsSnBr₃ is a p-type semiconductor. Our findings indicate that the CsSnBr₃ material is highly suitable for photovoltaic applications.

Based on the working mechanisms of heat pumps and chemical pumps, a model of the chemical heat pump operating between the two thermal material reservoirs with different temperatures and chemical potentials is established. The general expression of the coefficient of performance (i.e. generalized Carnot coefficient of performance) is derived, and a series of meaningful results are obtained. The different characteristics of the chemical heat pump operating under different conditions are revealed. It is found that the coefficient of performance of the chemical heat pump can be larger than that of the Carnot heat pump operating under the same temperature span or the reversible coefficient of performance of the chemical pump operating under the same chemical potential span. The reason is that the chemical heat pump operating between two thermal material reservoirs is driven by the temperature field and the chemical potential field at the same time. Moreover, it is expounded that these results accord with the second law of thermodynamics.

This study investigates the impact of initial temperature on the microstructure and mechanical properties of welded components, using molecular dynamics (MD). The stress–strain curves of the welded components, following various initial temperature treatments, revealed a double yielding phenomenon. Notably, there was a significant strain difference of 19.7% between the two yields. When the strain was loaded to the point of doubling yielding, stacking faults and twins covered the aluminum component part, while no such observations were made in the nickel component part. Additionally, tensile cracking occurred in the aluminum component part. The results indicate that treatment at varying initial temperatures alters the internal structure of the welded components. After the material yielded the first time, a significant number of disordered atoms and Shockley partial dislocations emerge, resulting in a substantial buildup of dislocation tangles and reduced dislocation migration rates. Consequently, the material exhibits a phenomenon of double yielding, with dislocation slip and deformation serving as the primary mechanisms. The optimal mechanical properties of the welded components achieved an initial temperature of 200K. Additionally, the effect of tensile temperature on the mechanical properties of the welded components were analyzed, and similar observations of double yielding were made. The significant number of dislocation tangles served as a barrier to dislocation slip, effectively enhancing the material’s mechanical properties. The simulation results provide theoretical support for the development of aluminum–nickel multilayer film self-propagation welding process.

Entanglement of the wave–particle duality of particles has attracted enormous attention as one of fundamental feature of quantum mechanics. Herein, we systematically studied the wave–particle entanglement of the particle system composed of N particles. The results indicate that the particle system has the wave–particle entanglement after the interaction, when the wave function of any one of the system can be obtained by using same basis vectors before the interaction. Moreover, a construction method of the wave–particle entanglement state is found for the particle system. Finally, the photons can show the wave–particle entanglement in the previous experimental work, which was further confirmed by the construction method. The results provide a new understanding for the entanglement of the wave–particle duality.

The non-Newtonian characteristic of the fluid flow phenomena has several applications in industries and the production of engineering gadgets. Based upon the role, the present work deals with the flow of Williamson nanofluid past two inclined parallel sheets. Further, the influence of radiating heat due to thermal radiation, Ohmic heating because of the magnetization, and inclined angle on Williamson fluid are presented, which are vital for the heat transfer enhancement. The proposed study became novel due to the scrutiny of entropy for the irreversibility processes within the system that is obtained due to heat transfer. The designed model with dimensional form is developed by converting to dimensionless forms with the help of similarity transformations. The finalized transformed equations are handled analytically using the Homotopy perturbation method (HPM). Heat irreversibility is calculated by inserting the observed values into entropy generation and Bejan number. The suggested method of solution for the momentum profile is verified by comparing it to a previously published numerical result in some limited circumstances, and great agreement is found. The result reveals that the entropy generation is enhanced near the upper wall of the channel for the magnetized particle but thermal radiation attenuates it, however, the fluid temperature boosts up for the enhanced coupling constraint i.e. for the existence of Eckert number.

The ZnO-10, ZnO-20, ZnO-30, and ZnO-40 nanopetal-shaped samples were successfully synthesized by a hydrothermal method. The results of XRD, SEM, TEM, and BET indicate that the micro–nano petal-like samples have the advantages of high purity, good crystallinity, and large specific surface area. The ZnO-20 sample with the largest specific surface area and pore volume was prepared by adjusting the scheme without changing the sample morphology. The specific surface area and pore volume of the sample were 33.6914m²/g and 0.1561ml/g. The results of gas sensitivity test show that the sample has the highest response and super good gas sensitivity selectivity. At 250^∘C, the responses to 5ppm and 50ppm ethylene glycol can reach 14.4 and 293, respectively. Because of the excellent gas performance of ZnO nanosheets, this work can provide a theoretical basis for the research and development of ultra-sensitive ethylene glycol gas sensors in the industry.

Effective thermal management is necessary for electronic devices to prevent overheating and guarantee optimal performance. The development of cutting-edge cooling methods may be aided by research into Triple Component Magneto-Convection (TCMC) in a superposed porous and fluid system with heat source/sink effects. It is feasible to improve the thermal management of electronic parts and systems by managing convective heat transfer via the optimization of heat source/sink spot and design. An investigation into the issue of TCMC in a horizontally infinite composite layer is presented in this work. The investigation takes into account of a consistent heat source or sinks in both layers as well as a uniform vertical magnetic field. The upper enclosure of the fluid layer is either free and adiabatic or isothermal, while the bottom enclosure of the porous layer is rigid and adiabatic. By employing normal mode analysis, the resulting system of ordinary differential equations is solved in closed form to obtain the eigenvalue, specifically the thermal Marangoni number (tMn). The investigation focuses on two different combinations of thermal boundaries: (i) adiabatic–adiabatic and (ii) adiabatic–isothermal. During the inquiry, the influence of major elements on TCMC in connection to the depth ratio is fully investigated. This work aims at understanding the stability of the superposed porous-fluid system using adiabatic and isothermal boundaries in the presence of a heat source or sink.

The micro-perforated panel structure has good sound absorption performance in medium and high frequencies, and the labyrinth metamaterial structure has good low-frequency sound absorption performance. Both the two structures are relatively simple, and can be obtained by simple processing with resin material, which is convenient for batch production. In order to enhance sound absorption ability for the sound absorption structure within low frequency, this research work has put forward one coupled structure via the micro-perforated panel and three second-order maze metamaterials structure, resulting in a coupled structure with a low-frequency sound absorption performance. Combination of equivalent circuit method calculates acoustic resistance and absorption coefficient for the sound absorption structure, and genetic algorithm has been employed to optimize the parameters of this sound absorption structure. Finally, the theoretical calculations analysis results have been verified by finite element simulation, which shows the trend of the curve of sound absorption coefficient of the two structures was basically consistent. And the sound absorption coefficient of the three peaks is all above 0.7, and the mean value of the sound absorption coefficient is above 0.6 at the acoustic frequency of 0–1500Hz, indicating that the coupled structure has a good performance of absorbing medium- and low-frequency sound waves.

This paper presents an ultra-wideband microwave absorber with a composite of carbonyl iron powder (CIP) and thermoplastic polyurethane (TPU) material and a wide-angle absorption stacked cross structure. The simulation results show that although the total thickness is less than 3.21mm, the proposed device can achieve high absorption (over 90%) in the range of 7.55–100GHz, and the total bandwidth is 92.45GHz, with a relative bandwidth of 172%. In addition, the absorber is insensitive to the polarization characteristics of incident electromagnetic waves and can achieve a wide incident angle absorption of up to 60^∘.

Using density functional theory, the effects of Pb${}^{2+}$ coverage and Fe modification on the electronic properties of black phosphorus in water were calculated. The investigation found that the increasing of Pb${}^{2+}$ coverage improves the stability of the structure and the adsorption height, and makes the bond length of the P–P bond continuously increase, and the modification of Fe further increases the adsorption height of the system. Black phosphorene has a direct bandgap semiconductor structure in water, with a bandgap value of 0.759eV, and the adsorption of Pb${}^{2+}$ makes it a metal structure, and the modification of Fe makes the bandgap reopened and becomes a direct bandgap semiconductor structure. Intrinsic black phosphorus has strong sp orbital hybridization, s orbital and p orbital make great contributions to the conduction band and valence band, the adsorption of Pb${}^{2+}$ makes the total density of states increase, and the value of the density of states at the Fermi level increases, the density of states crosses the Fermi level, and the system exhibits metallicity. It can be seen that the adsorption of Pb ions and the modification of Fe have changed the structural properties of the black phosphene system in aqueous solution, and the structural stability of the system has been continuously improved, which has important guiding significance for removing Pb ions in water, purifying water quality, protecting ecological environment and human life and health.

Singular integrals that appear in calculations of quantum electrodynamic (QED) corrections for three-body Coulomb systems are studied using Hylleraas coordinates. A general scheme is developed to separate divergent parts of singular integrals involving Hylleraas basis functions. Subsequently, the obtained singular integrals can be used in the calculations of QED corrections. The numerical results of two typical operators that appear in $m{\alpha }^5$ order QED corrections are precisely calculated. The leading radiative corrections are presented as well. These singular integrals would be intensively used in the calculations of high-order QED corrections for three-body systems such as helium, lithium ions, and hydrogen molecular ions.

This paper proposes a dual-channel high sensitivity photonic crystal fiber sensor with rectangular air holes, which can detect the refractive index of a single sample or detect the refractive index of two samples simultaneously, to increase the detection efficiency and wavelength sensitivity of the sample refractive index. The sensor can reduce the times of filling, emptying and cleaning of the sample to be tested and save labor and time costs. The finite element method is used to thoroughly analyze the proposed structure’s sensing properties. The results show that when the sensor detects a single sample, the maximum wavelength sensitivity is 67,300nm/RIU, and the highest figure of merit (FOM) is 547 RIU${}^{-1}$. When the sensor detects two samples synchronously, the maximum wavelength sensitivity is 64,100nm/RIU, which is the highest level among the known sensors of the same kind. It has good application prospect in the field of high sensitivity refractive index detection.