Modern Physics Letters B

The electronic and structural characteristics of the armchair and zigzag single-walled AlN nanotubes (SWAlNNTs) have been considered by using density functional theory (DFT). The effects of tube diameter on the Al–N bond length, the buckling separation, tube lengths, valence band maximum (VBM), conduction band minimum (CBM), Fermi energy, strain energy, and bandgap have been studied. The strain energy calculation revealed that higher-diameter nanotubes are more stable than those with smaller diameters consequently at the same chirality armchair AlNNTs are more stable than zigzag types. It revealed a correlation between the bandgap and buckling: the smaller the bandgap, the higher the buckling, and the buckling separation increases by decreasing tube diameter. The 2p-orbitals of Al and N atoms have the most contribution to CBM and VBM, respectively. All zigzag and armchair AlNNTs are semiconductors having direct and indirect bandgap, respectively. It is also found that for both zigzag and armchair AlNNTs, with increasing nanotube diameter, the bandgap increased. The conclusions of this study can definitely be useful in future experimental works on optoelectronic devices.

This work considers the analytical analysis of silver-water, silver-blood base nanofluid flow over fluctuating disk with the influence of viscous dissipation over fluctuating disk. The primary goal of this study is an effort to improve the heat transfer ratio, which is a core part of the engineering and industrial sectors. Following a continuity check, the problem is modeled using the conservation rules of momentum and energy. Nonlinear PDEs are produced through modeling, which are then transformed into ODEs using a similarity transformation and thermophysical characteristics. The resultant ODEs are resolved using the Optimal Homotopy Asymptotic Method (HAM). The outcomes of this method are compared to authenticate the outcomes of the obtained results. The Mathematica software is used to run HAM methods, and graphical interpretations are given to highlight the influence of dissimilar contributing factors on the velocity profile and temperature distribution. Nusselt’s number, and the skin friction are examined through graphical representation. Convergence of the problem is checked with the help of graphs and tables by using dual solution of the problem.

In this study, we focus on exploring the propagation characteristics of particle swarms in social networks and analyze the diffusion process of viruses among populations based on system dynamics. The article mainly discusses three propagation influence mechanisms, including individual attributes, group attributes, and particle swarm attributes, and delves into the modeling of diffusion processes based on network structures. Firstly, we adopt the main roads in the transportation network (hub nodes) as the initial network backbone. On this basis, by introducing branch networks with small-world characteristics and scale-free characteristics, we construct a transportation network that integrates multiple properties. Using this network, we conducted a detailed simulation and analysis of the COVID-19 transmission process and compared and verified it with the infection dynamic data of COVID-19 in Shanghai from March to September 2022. The verification results reveal that our proposed model can significantly improve prediction accuracy. Compared with other existing dynamic models, our model demonstrates excellent performance, possessing high practical application value. This study provides robust theoretical support for the propagation characteristics of particle swarms in social networks and lays the foundation for further research and application in related fields.

This work aims to study the optoelectronic and thermoelectric properties of the new perovskites LiSnX₃ (X$=$Br or I). This study is carried out by using the density functional theory (DFT) combined with the Boltzmann transport theory. First, the investigation of the structural, electronic and optical properties of such materials, using the Generalized Gradient Approximation (GGA), has been performed. This latter method has been performed under the Perdew–Burke–Ernzerhof (GGA–PBE) approximation applying the exchange correlation potential. It is found that the two compounds exhibit a p-type semiconductor characteristic and interesting optical properties. Moreover, the thermoelectric properties of the studied materials, such as the Seebeck coefficient, electrical conductivity, thermal conductivity, figure of merit and power factor, have been examined. It is found that the Seebeck coefficient takes positive values. This finding reveals and confirms the p-type semiconductor characteristic for two studied compounds. On the other hand, such materials display large values of the figure of merit (ZT) in comparison with the existing thermoelectric materials. Such large values of ZT are found for both small or large temperature values. The obtained results of the optoelectronic and thermoelectric properties show that these materials could be useful both for photovoltaic and thermoelectric applications.

The thermodynamic and mechanical properties of the zinc-blende indium pnictides InP, InAs and InSb compounds have been investigated thanks to the statistical moment method in statistical mechanics. We have derived the analytical expressions of thermal induced atomic displacement, lattice constant, elastic moduli (Young’s modulus, bulk modulus and shear modulus) and elastic constants of the zinc-blende compounds. The difference of temperature effects on mechanical properties of InSb comparing to InP and InAs compounds has been pointed out. We show that InSb is less affected by temperature while InP changes its mechanical properties from hardness to softness quickly when the temperature increases. The advancement of this method is that it has included the anharmonic effects of thermal lattice vibrations by taking into account the higher-order atomic displacement terms.

CuO pricky microspheres have been synthesized without additives by calcination after hydrothermal treatment at $120^{\circ }$C for 6h. The product was characterized by SEM, TEM, EDS, etc. The unique pricky microspheres were formed with NH₄HCO₃ and urea as precipitators. Through a series of reaction experiments, the possible formation mechanism of nucleation, growth and secondary growth was proposed. With the assistance of H₂O₂, the degradation rate of RhB aqueous solution reached 87.16% after 50 min by simulated visible light degradation, which proved the good photocatalytic performance of the CuO pricky microspheres. After four cycles of degradation experiments, the degradation rate of RhB aqueous solution is still above 80%. The radical capture experiments showed that the main active groups in the degradation process were ⋅OH and $\cdot {\mathrm{\text{O}}}_2^{-}$, and the mechanism of photocatalytic degradation of Rhb was proposed.

The aim of this paper is to construct a six-component integrable hierarchy associated with a matrix spatial spectral problem of arbitrary order. The adopted method is the zero curvature formulation. The corresponding Hamiltonian formulation is furnished by using the trace identity, which guarantees the Liouville integrability for the resulting hierarchy. Two illustrative examples of integrable equations of lower orders are six-component coupled nonlinear Schrödinger equations and modified Korteweg–de Vries equations.

This work considers the analytical analysis of graphene oxide ethylene glycol and graphene oxide blood base nanofluid over a vertical sheet. The principal objective of this study is to make an effort to improve the heat transfer ratio, which is the core part of the engineering and industrial sectors. Following a continuity check, the problem is modeled using the conservation rules of momentum and energy. Nonlinear PDEs are produced through modeling, which are then transformed into ODEs using the similarity transformation and thermophysical characteristics. The resultant ODEs are resolved using the Homotopy Asymptotic Method, and graphical interpretations are given to highlight the influence of different contributing parameters such as unsteady parameter, nanoparticle volume fraction, mixed convection parameter, Grashof number and Prandtl number on the velocity profile and temperature distribution. It is noted that increasing the values of nanoparticle volume fraction and stretching parameter slow down the velocity profile. Also, increasing the values of mixed convection parameter and Grashof number (Gr) enhance the velocity profile, and increasing values of Prandtl number and Graship number reduce the temperature distribution. The Nusselt number and the skin friction are examined through graphical representation. It is noted that increasing the value of mixed convection parameter decreases the skin friction of the fluids, and the Nusselt number decreases with the growing value of Prandtl number.

In this paper, we discuss the forced convective heat transfer of power-law fluid flow through porous annular sector duct by applying the Brinkman-extended Darcy flow model. A strongly implicit procedure (SIP) is utilized to solve the algebraic momentum and energy equations which was discretized by using the finite volume method (FVM). The effects of permeability factor and power-law index corresponding to the Brinkman-extended Darcy flow model and power-law fluid, respectively, on flow and heat transfer rate are carried out numerically and graphically against different values of parameters corresponding to geometrical configuration. In the pseudo-plastic fluids, a maximum decrease of more than $100\%$ has been observed in $f\mathrm{\text{Re}}$, whereas maximum decrease in dilatant fluid is around $30\%$, when we increase the values of k. A decrease of 16.02% in Nu has been carried out in pseudo-plastic fluid, whereas unforeseen decrease in Nu has been observed in both Newtonian and dilatant fluids comparably pseudo-plastic fluid for particular values of k.

ZnS nanoparticles (NPs) are prepared by co-precipitation method using ethylene diamine tetra-acetic acid as a stabilizer and capping agent. The structural, morphological and optical properties of as-synthesized NPs are investigated using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, ultraviolet-visible (UV-Vis) absorption, and photoluminescence spectroscopy. The X-ray diffraction pattern exhibits a zinc-blended crystal structure at room temperature. The particle size was found to be in the range of 22.22 nm. The ultraviolet absorption spectrum shows the blue shift in the bandgap due to the quantum confinement effect. The photoluminescence spectrum of ZnS NPs shows a blue visible spectrum. The template of the cyclic voltammetry contour demonstrated a strong rate suggesting that the ZnS nanostructure electrode has a reduced polarization effect. The above studies have provided resplendent efficiency and proven that ZnS NPs can be used as a prominent material for supercapacitor applications.

Nitrogen (N) is an important impurity in silicon (Si), which associates with impurities as well as with other defects to form defect complexes. The knowledge of the properties and behavior of defect structures containing carbon (C), N and oxygen (O) is important for the Si–based electronic technology. Here, we employ density functional theory (DFT) calculations to investigate the association of nitrogen with carbon and oxygen defects to form the C_iN and C_iNO_i defects. We provide evidence of the formation of these defects and additional details of their structure, their density of states (DOS) and Bader charges. Therefore, C_iN and C_iNO_i defects are now well characterized.

In this paper, the structural, electronic, optical, and mechanical properties of the hexagonal Ceria CeO₂ have been studied with hybrid functionals. The rare-earth oxide compound exhibits a $\mathrm{\Gamma }-M$ indirect bandgap, with a bandgap energy of 2.706 eV. The electronic bandstructure has been described in detail in terms of orbital states. The rare-earth Ce f orbital contributes to the conduction band and transitional Ce d, O s electron orbitals to the valence bands. Our optical spectra also fully explain the structural and electronic properties of the material. (i.e. atomic-bonding, density or capacity inside Cerium oxide system, and the excitation of electrons to transfer from valence O 2p to conduction Ce f orbitals, leading to orbital hybridizations, etc.). Finally, our elastic coefficients verify the mechanical stability of our Ceria system. Our bandgap energy found is in excellent agreement with the experimental data. A high optical absorption coefficient of up to $1\times 10^5$ cm${}^{-1}$ is found, indicating a good material absorption within the ultraviolet C (UVC) range. The findings of this work would be beneficial to both theoretical and experimental research works to explore the potential applications of CeO₂ in optoelectronics devices.