Modern Physics Letters B

Blood clotting caused by COVID-19 has made this disease much more severe than other respiratory diseases. An alarming number of COVID-19 patients developed blood clots that trigger heart attack, stroke, and other disasters. Currently, blood thinner medicines are the only treatment. While blood thinners lower the blood’s ability to clot, they cannot disassemble existing blood clots. Many patients were not helped by them. Here we report our finding: Strong magnetic field can disassemble blood clots safely and effectively. This is attributed to the magnetic property of red cells and their unique disk shape. Hence, we have proposed a new treatment for patients with thrombosis: applying a strong magnetic field along the patients’ arm or leg. When the blood clots come to the magnetic field, they are disassembled safely; red cells recover their oxygen function; the blood viscosity along the flow direction is reduced, turbulence in blood circulation is suppressed, and the incidence of heart attack and stroke can be prevented. With thrombosis occurring in COVID-19 patients, the magnetic treatment will resolve this urgent issue and greatly help the patients to recover.

Pure hexagonal $\beta$-NaYF₄ micron crystals were synthesized by the hydrothermal method with the up-conversion luminescence properties studied by doping Yb${}^{3+}$/Ho${}^{3+}$. The up-conversion fluorescence spectra and fluorescence lifetime of $\beta$-NaYF₄ micron crystals were determined by FLS-980 transient fluorescence spectrometer. By changing the doping concentration of Yb${}^{3+}$/Ho${}^{3+}$, the optimal doping concentration was confirmed to be 20%Yb${}^{3+}$/2%Ho${}^{3+}$. The fluorescence spectrum was obtained by changing pump power, the relationship between power and intensity was analyzed, and the $\beta$-NaYF₄ micron crystal green and red emission up-conversion process was obtained into a two-photon process. The ⁵F${}_4{\to }^5$I₈ and ⁵S${}_2{\to }^5$I₈ of the sample were thermally coupled to obtain a large absolute sensitivity (Sa) of low temperature. The maximum absolute sensitivity within the range of 64–194K is 0.0097K${}^{-1}$ at 144K, while maximum absolute sensitivity at 333K is 0.00335K${}^{-1}$ in the range of 293–493K. The experimental results show that the sensing characteristics of $\beta$-NaYF₄:Yb${}^{3+}$/Ho${}^{3+}$ at low temperature are better than those at high temperature, and it has the potential to be used in the field of temperature sensing.

This investigation deals with the flow of Al₂O₃–water nanofluid in a wavy porous channel embedded in porous rocks. Fluid exchange takes place uniformly between porous rocks and the wavy channel. In this analysis, cylindrical and parallel plate wavy porous channels are considered. Consequences of Brownian motion and thermophoresis on the flow inside a wavy porous channel are elucidated. The modeled equations are made dimensionless by using dimensionless quantities. Impacts of flow parameters on the velocity, temperature, Nusselt number and friction factor are depicted through graphs. The numerical results with respect to parallel plate wavy porous channel are validated by comparing with the published results. The effectiveness of the cylindrical wavy porous channel as a heat transfer enhancement device in comparison to the parallel plate wavy porous channel is confirmed in this study. Designing devices at microlevels and understanding the heat transfer enhancement mechanism in wavy channels using the nanoparticle addition are the major outcomes from the results of this numerical investigation. The heat and mass transfer rate enhancements in the wavy porous channels are due to the higher Brownian motion in the boundary layer region and accelerated thermophoresis through thermal and concentration boundary layer thicknesses.

The proposed study examines the effect of inclined magnetic field on a ternary hybrid nanofluid flow that is axisymmetric thermo-solutal Marangoni convective over an infinite disc. Some well-known uses of Marangoni convection include semiconductor production, atomic reactors, crystal growth, fine art mechanisms, melting, thin-film stretching and welding processes. The non-uniform heat generation and viscous dissipation are taken into account. The thermal conductivity and diffusivity coefficient are presumed to vary inversely with linear function of temperature and concentration. The ternary hybrid nanofluid, which consists of silicon dioxide (${\mathrm{\text{SiO}}}_2$), iron oxide (${{\mathrm{\text{Fe}}}_3\mathrm{\text{O}}}_4$), molybdenum disulfide (${\mathrm{\text{MoS}}}_2$) and ethylene glycol as base liquid, undergoes an energy transition to improve heat transfer. The system of PDEs is transformed into nonlinear ordinary differential equations (ODEs) by using the appropriate transformations. Using the BVP4C method, this problem is numerically solved. The heat and mass phenomena rates on flow behavior are investigated using tables and graphs to address the impact of several physical and flow parameters on velocity, concentration, and thermal profiles. By increasing the Marangoni convection parameter, the surface tension gradient gets stronger, leading to more efficient heat and mass transfer inside the liquid as well as stronger induced flows. As the temperature and concentration profiles decrease, the outcome is a more consistent dispersion of these properties throughout the liquid.

The goal of this probing is to scrutinize the impact of chemical reaction and radiation on the flow behavior of a nanofluid, made up of copper nanoparticles suspended in water, as it moves through a vertically oscillating plate in a magnetohydrodynamic free, unsteady convective system. We tackled the problem with a mathematical model incorporating nanoparticle volume fraction and used a closed-form Laplace transformation method to resolve the governing equations for momentum, energy, and concentration field. The results were also depicted graphically with heat transport rate, mass transport rate, and skin friction illustrations. The study shows that increasing the volume fraction of Cu–water-based nanoparticles decreases primary and secondary velocities, while the temperature field grows. Moreover, a higher chemical reaction parameter leads to a drop in the fluid concentration. Furthermore, a graphic representation of the upshots of variant dimensionless parameters on the nanofluid velocity, temperature, and species concentration is provided. The subject of this paper explores an extension that involves the inclusion of Cu–water-based nanofluid. This nanofluid exhibits significantly higher thermal conductivity compared to typical fluids. Consequently, it can be considered a superior alternative to conventional fluids, proving to be valuable in enhancing heat transfer in diverse engineering and industrial processes. This study is significantly relevant to various industrial and machine-building applications.

A first-principles method was used to explore the influence of tensile strain on the electrical and optical characteristics of Nb-doped MoSe₂. The tensile strain has been discovered to have a higher influence on the electrical structure of the Nb-doped MoSe₂ system than pure monolayer MoSe₂. According to the energy band structure study, the pure monolayer MoSe₂ is a direct bandgap semiconductor, but the system doped with Nb instead of Mo atoms is a p-type-doped semiconductor. The bandgap of the Nb-doped MoSe₂ system decreases gradually with the increase of tensile strain, but still maintains the p-type semiconductor properties, and the bandgap of the pure monolayer MoSe₂ also decreases gradually with the increase of tensile strain. From the density of states analysis, it is found that for the total density of states of the doped system at different tensile strains, it is mainly contributed by the Mo-4d and Se-4p orbitals. The optical properties analysis showed that the doped system under tensile strain had higher absorption coefficient and reflectance peak than the Nb-doped MoSe₂ system without tensile strain. Additionally, the doped system showed redshift phenomenon in both the absorption and reflection peaks as the tensile strain increased.

A model condition for the propagation of ultrashort pulses in optical fiber frameworks could be established through the extensive generalization of the nonlinear Schrödinger equation introduced by Triki and Biswas. This study uses two significant and effective trustworthy methods to examine the Triki–Biswas (TB) equation. Sardar Subequation Methods (SSM) and the generalized Kudryashov (KUD) method generate solutions for trigonometric, hyperbolic, exponential, and rational functions. These approaches are specifically designed for handling solitary wave patterns, dark-singular-mixed solitons, combined dark-bright solitons, singletons, bright solitons, exponential and rational functions, as well as periodic solitons. All of these solution classes contribute to the physical dynamics of outcomes. These findings represent an innovative extension of the soliton domain within the TB model and are being reported for the first time in our investigation. In addition, Mathematica simulations are used to display the 3D and 2D graphs to explain the identified solutions’ physical dynamics.

This paper presents the results of a study of the dielectric constant of solutions of a polar liquid in a nonpolar solvent: chlorobenzene–benzene, chlorobenzene–hexane. The measurements were carried out at a wavelength $\lambda =12.80$cm in the temperature range from $-80^{\circ }$C to $20^{\circ }$C. The studies were carried out using the dielectric spectroscopy method. This method allows a more detailed study of the dielectric properties of the objects of study due to the large equilibrium (“static”) dielectric constant of the object. The temperature dependence of the dielectric relaxation time of molecules in the liquid and solid states of the studied solutions is determined. It has been established that with increasing concentration (0.300, 0.562, 0.794, 1.000 for a chlorobenzene–hexane solution and 0.179, 0.368, 0.567, 0.778, 1.000 for a chlorobenzene–benzene solution) of the halogen substituent, the relaxation time increases. The measurement results of dielectric constant ${\epsilon }^{\prime }$ and absorption coefficient ${\epsilon }^{\prime \prime }$ obtained for concentrated solutions chlorobenzene–benzene, chlorobenzene–n–hexane at wavelengths $\lambda =12$, 80 and $\lambda =3,26$cm at temperature $20^{\circ }$C are given in the paper. The static dielectric constant is obtained at a frequency of 1MHz. The obtained experimental values ${\epsilon }^{\prime }$, ${\epsilon }^{\prime \prime }$ and ${\epsilon }_0$ of investigated systems in (${\epsilon }^{\prime }$, ${\epsilon }^{\prime \prime }$) plane locate on the semi-circle the center of which is on ${\epsilon }^{\prime }$ axis. In this case, the high-frequency limit value of $\epsilon \infty$ dielectric coefficient exceeds the corresponding n₂ refraction index square. The macroscopic and molecular relaxation times are calculated on the base of experimental data. The thermodynamic quantities characterizing the process of dielectric relaxation are calculated for solutions of chlorobenzene–benzene, chlorobenzene–hexane. It has been determined that the height of the potential barrier separating the two equilibrium positions of a polar molecule is greatest in the state of a pure polar liquid and decreases with dilution in a nonpolar solvent.

The capacity of Phononic crystals (PCs) to form bandgaps (BGs) that limit the transmission of elastic/acoustic waves is a key property that is particularly beneficial for vibration/sound isolation and signal processing. In this work, a parametric analysis of Poisson’s ratio of rubber, and the density, geometry and size of scatterer on the BGs of porous, solid/solid, fluid/solid and solid/fluid PCs is presented. Based on the simulation results, it is found that the width of the first absolute bandgaps (FABGs) of porous PCs is not necessarily proportional to the porosity due to the pore shape; when Poisson’s ratio of compressible and incompressible rubber is increased, the FABG width of porous PC decreases dramatically. In addition, the FABGs of solid/solid PCs are strongly dependent on whether the rubber is a matrix or scatterer; the fluctuation of the FABGs is also highly related to the density of the solid. Fluid–structure PCs have smaller FABGs than porous and solid/solid PCs, and these FABGs usually occur within higher-order energy bands. Rubber compressibility significantly affects the FABGs of porous and solid/solid PCs, but almost not fluid-structural PCs. The results presented in this work offer guidance to tune the BG and design acoustic devices in various practical applications such as noise and vibration insulators.

The main purpose of this work is to optimize the mechanical properties of tungsten–copper (W–Cu) nanocomposite fabricated by the sintering process. For this purpose, the parameters of sintering temperature, sintering time and weight percentage of copper were selected to optimize the compression strength, impact strength, hardness and corrosion resistance of the W–Cu nanocomposite using the desirability function procedure and response surface method. The analyses of transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were also performed to examine the microstructure of W–Cu nanocomposite. The results exhibited that a rise in the sintering temperature from 1000^∘C to 1150^∘C significantly enhanced the impact strength of W–Cu nanocomposite, while a rise in the sintering temperature from 1150^∘C to 1300^∘C deteriorated the impact strength. Moreover, the compression strength and hardness of the W–Cu nanocomposite continuously improved by elevation of sintering temperature from 1000^∘C to 1300^∘C. A rise in the amount of Cu from 20wt.% to 40wt.% led to a reduction in the hardness of the W–Cu nanocomposite, while a rise of Cu content improved the impact and compression strengths. The results also indicated that the mechanical properties of W–Cu nanocomposite enhanced simultaneously by using 27wt.% Cu at sintering temperature of 1197^∘C and sintering time of 2.7h. The samples sintered at the optimal conditions indicated a higher corrosion resistance than that sintered at the initial conditions.

The structural, electronic, magnetic, magnetocaloric, and thermoelectric properties of the SrXO₃ (X = Mn and Fe) perovskite compounds were investigated using first-principles calculations. It was observed that the SrXO₃ compounds are G-anti-ferromagnetic perovskites with partial magnetic moment with a value of 2.7 ${\mu }_B$ and 2.4 ${\mu }_B$ for Mn-3d and Fe-3d orbitals for SrMnO₃ and SrFeO₃, respectively. Moreover, by using Monte Carlo simulation (MCs) combined with the Metropolis algorithm, the calculated coupling interactions between the magnetic atoms Mn–Mn and Fe–Fe are $J_1^{\mathrm{\text{Mn}}}=5.17$meV and $J_2^{\mathrm{\text{Mn}}}=-0.6$meV for SrMnO₃, $J_1^{\mathrm{\text{Fe}}}=3.44$meV and $J_1^{\mathrm{\text{Fe}}}=-0.4$meV for SrFeO₃, respectively. Furthermore, a significant magnetocaloric effect (MCE) was observed around the Néel temperature of $T_N^{\mathrm{\text{Mn}}}=260$K (for SrMnO₃) and $T_N^{\mathrm{\text{Fe}}}=134$K (for SrFeO₃), and the maximal simulated magnetic entropy and relative cooling power values of all the studied compounds are found to be 100J/kg (for SrMnO₃) and 110J/kg (for SrFeO₃), respectively, with an applied magnetic field of $H=4.0$ T. These results are in complete agreement with the experimental results and more specifics than other theoretical calculations. Hence, SrXO₃ compounds are considered promising candidates for magnetic refrigeration at low temperature.

Using the BVS method, we calculate Li-ion pathways and diffusion barriers in the interface between silicene and MgCl₂, MgBr₂ and MgI₂ substrates and we show that the results are in good agreement with the previously published DFT studies. In addition, we showcase that BVS does not need the exact crystal structure as we examine different initial positions for the Li ion and different interface heights without affecting the calculated $\mathrm{\text{BVSE}}$. Furthermore, we show that surface diffusion BVS calculations can be used to roughly optimize the interface, thus completely foregoing DFT geometry optimization calculations. Here, we propose that BVS can substitute DFT as a quick filter when searching for low migration barriers in silicene-based materials, providing good enough accuracy.

Unconventional superconductivity on a honeycomb lattice has received increasing interest since the discovery of graphene primarily due to the similarities between materials with a honeycomb lattice and cuprate superconductors. Many theoretical studies have been conducted on superconductivity on a honeycomb lattice, however, a consistent picture is still lacking. In this paper, we have extended the theory of kinetic-energy-driven superconductivity, which has been developed to investigate unconventional superconductivity in cuprate superconductors, to explore superconductivity on a honeycomb lattice within the t-J model. Our results demonstrate that the charge-carrier pair gap parameter with $d_{x^2-y^2}+\mathrm{\text{i}}{d}_{xy}$-wave symmetry exhibits a dome-like shape as a function of doping, with superconductivity emerging at a certain doping concentration and disappearing at high doping levels, similar to what has been observed in cuprate and cobaltate superconductors. Furthermore, the charge-carrier pair gap parameter decreases with increasing the value of $J∕t$ (the ratio between the antiferromagnetic exchange coupling constant and the nearest-neighbor hopping integral), and approaches zero when $J∕t$ reaches a sufficiently large value. This indicates that the antiferromagnetic order will suppress the superconducting state and a sufficiently strong exchange coupling will completely destroy the superconductivity. Taking into account our present results together with the corresponding results of cuprate and cobaltate superconductors, it appears that the dome-like shape of the doping dependence of the charge-carrier pair gap parameter may be a common feature in doped Mott insulators.

We theoretically investigate the polarized terahertz (THz) generation in laser–gas interaction using circularly polarized (CP) two-color laser pulses with uncommon frequencies. We show that these laser pulses can be applied to generate polarized THz radiation, and the polarization of THz radiation, which ranges from linear to circular, can be controlled in a flexible manner by manipulating the laser parameters, such as the relative phase and phase angle. Furthermore, in contrast to traditional harmonic frequency combinations, the polarization states of the incommensurate lasers undergo complex evolution with the phase angle, resulting in a noteworthy influence on the THz yield. The obtained results could deepen our understanding of polarized THz radiation generation.

In this study, we have conducted a thorough investigation into the influence of the atomic radius of transition metals on the structural, electronic, and optical properties of nanolaminated borides MAlB ($\mathrm{\text{M}}=\mathrm{\text{Cr}}$, Mo, W) using first principles calculation. The validity and dependability of our calculation parameters are confirmed and compared with other available data sets. The calculated elastic constants reveal stronger resistance to deformation along the c direction as compared to the a- and b-directions. The mechanical properties of these borides increased in tandem with the atomic radius of transition metal. The chemical bonding within the borides is a mix of metallic and covalent bonds. Interestingly, there is a decrease in the boride metallicity concurrent with an increase in the atomic radius of the transition metal. Optical property analysis shows promise for these borides as absorbent materials. Furthermore, there is a correlation between the increase in the atomic nucleus of the transition metal and the increase in the maximum absorption coefficient.