International Journal of Modern Physics B

The industry is the key to economic development. This paper proposed a fractal evolutionary dynamic model of industry based on the propagation dynamics theory from the perspective of fractal theory. The model quantitatively portrays the evolutionary trend of industries and provides reasonable solutions to the problems faced by industrial structure optimization. First, the fractal characteristics of the industrial system are analyzed, and the proposed model is used to study the evolution of industry and enterprise impact values at different granularities. Subsequently, the impact of micro firms on the macro industrial development was further investigated. Finally, the correctness of the model simulation results was verified by real data. The results showed that the evolution of industries under different granularities shows self-similarity and that micro industries with small and medium-sized enterprises (SMEs) were more influential in the development of industries. Finally, the proposed fractal evolutionary dynamics model of the industry has proven to be reasonable and effective through empirical comparison. This study provided new insights for solving industrial development problems with high theoreticality and reliability.

Solar water splitting has attained much attention in recent years for renewable and clean production of hydrogen from water under irradiation by sunlight. Solar water splitting has been progressively at the forefront of chemical research and also provides a promising path for sustainable hydrogen production. TiO₂ has a wide range of applications and is considered as one of the most propitious semiconductors due to its photo-stability, low price and chemical stability. TiO₂ nanotubes have been prepared by using electrochemical anodization method followed by organic dye deposited onto the TiO₂ nanotubes. rGO-supported TiO₂ nanotubes and dye-doped graphene-supported TiO₂ nanotubes show more efficient behavior for water splitting as compared to pure TiO₂ nanotubes. The surface morphology, elemental composition, structure and size of the nanocrystalline TiO₂ nanotubes and dye-doped graphene-supported TiO₂ nanotubes were examined by using SEM, XRD, EDX and UV/Visible spectroscopy, respectively. Dye-doped graphene-supported TiO₂ nanotubes have been utilized for efficient solar water splitting.

This research work aims to understand the structural, electronic, elastic and thermoelectric properties of half-Heusler RhVX (X = Si, Ge) compounds. The included properties are explored by using the full-potential linearized augmented plane wave method under the support of density functional theory by employing Wien2k computational code. Within the calculations, the lattice constant of RhVSi is found as 5.69 Å and for RhVGe as 5.74 Å. These values are in admirable agreement with the existing literature. Further, both the half-Heusler compounds are explored as ductile in ground state from the calculation of elastic and mechanical properties. The narrow indirect bandgap (0.21 eV for RhVSi and 0.33 eV for RhVGe) semiconductor character of both the RhVX compounds is revealed from the results of electronic properties. The thermoelectric performance of RhVX compounds is analyzed by calculating the important parameters such as thermal conductivity (both electronic and lattice), Seebeck coefficients, carrier concentration and figure of merit. Both the RhVX compounds are suggested as suitable candidates for thermoelectric power generators at high temperatures.

There arises the formation of thin films of cobalt monosilicide (CoSi) deposited into the base surface of SiO₂/Si (111) using magnetron ion-plasma sputtering and subsequent thermal annealing. It was found that, in addition to the formation of CoSi silicide, also there are Co and Si atoms that do not form bonds on the surface. Therefore, in this work, we studied the surface morphology and composition of a CoSi silicon target using a scanning electron microscope. The study, silicide CoSi, was chosen as the target and standard SiO₂/Si (111) was used as the substrate. The surface morphology and composition of the CoSi silicon film obtained by scanning electron microscopy had been studied. The paper reports on a method, morphology of the surface of a CoSi silicon film obtained using Raman microscopy. The results obtained are based on the fact that they were obtained using a modern magnetron sputterer, a high-vacuum thermal heater and modern devices.

We construct a kind of substitution networks and investigate their eccentric Fermat distance sum. In terms of some singular integrals, we solve the integral using the approach of finite pattern, and gain their asymptotic formula on eccentric Fermat distance sum.

The dynamic magnetic properties of the nonequilibrium Fe₄N system are calculated on the basis of correlated effective-field theory (EFT). The dynamic phase diagrams are plotted for different values of the oscillating magnetic field and the crystal field. The reentrant behavior, the dynamic tricritical point and the dynamic critical end point observed in certain case by using EFT are established to emerge as the generic nonequilibrium features of the Fe₄N system. Moreover, we compare our results with those produced by mean-field theory (MFT), and find that the first-order phase transition and the reentrant phenomena are significantly reduced due to the consideration of spin–spin thermal fluctuations in EFT approximations. Our findings lead us to conclude that the thermal fluctuations considered in EFT are a critical factor for the dynamic magnetic properties of the nonequilibrium Fe₄N system.

To attain a new system with a higher rate of freezing, two approaches were utilized in this paper namely: (1) loading alumina nanoparticles; (2) involving curved walls. The geometry has two cold surfaces and pure PCM is water. The convection role in this mechanism is very low and so the related terms have been neglected in modeling. By adding source term of freezing in energy equations and removing the advection terms, the final form of mathematical model will appear. Finite element method, by involving the implicit technique, has been selected for simulations and to increase the correctness of code, an adaptive grid has been utilized. For better description of efficacy of alumina nanoparticles, influences of size and amount of powders have been examined. As greater sizes are utilized, the period firstly decreases around 19.98% then it augments around 49.13%. Besides, the dispersion of powders results in 70.06% reduction in freezing time.

There are several regularly reported applications for the dispersion of nanoparticles in a conventional fluid along a vertical wall in clinical medicine, architecture and agriculture fields. On the other hand, it still has not been reported the effect of electromagnetohydrodynamic convective flow of nanofluid through a radiating, moving Riga plate with heat absorption. As a result, this paper examines a water-based nanofluid comprising copper and aluminum oxide along a moving Riga plate, taking into cognizance $\lambda =0$ (stationary Riga plate) $\lambda =\pm 1$ (moving Riga plate). The Laplace transform technique is used to solve the ODEs obtained after employing the similarity variables on the governing equations. The effect of various variables on the shear stress coefficient, Nusselt number, velocity and temperature distribution is explored and graphically shown. Driven by the electromagnetic force effect, the increased modified Hartmann number and radiative impact increase copper nanofluid over aluminum oxide nanofluid on the moving plate. Simultaneously, heat absorption favors a modest decrease in aluminum oxide nanofluid’s thermal and velocity fields over copper nanofluid.

In this study, the design and performance estimation of tin (Sn)-based planar $p$–$n$ homojunction perovskite solar cell (PSC) have been carried out. Here, the effect of maintaining the intrinsic active layer thickness and replacing the intrinsic active perovskite $i$-layer of a standard $n$-$i$-$p$ structure of lead (Pb)-free PSCs with a $p$–$n$ homojunction is fully investigated. When the active layer is divided into a $p$–$n$ junction layer, it increases the photo-generated electrons and holes efficiency due to the built-in electric field of the junction. Furthermore, in order to get a better insight, the effects of various technological and device dimensional parameters on the performance of the reported PSC have been studied. It has been reported that the thickness of the p-side with methyl-ammonium tin triiodide (MASnI${}_3)$ layer must be greater than the n-side of the MASnI₃ layer. Meanwhile, its acceptors concentration should be slightly lower than the donors’ concentration on the n-side of MASnI₃ layer to achieve maximum power conversion efficiency (PCE). Using the optimized parameters, our design demonstrates an open-circuit voltage ($V_{oc})$ of 0.89 V, short-circuit current density ($J_{sc})$ of 32.36 mA/cm², fill factor (FF) of 74.40%, and PCE of 21.46%. This advocates the huge potential and great opportunities for deploying these Pb-free PSCs for eco-friendly photovoltaic applications.

To find periodic solutions of nonlinear equations, the Jacobi elliptic function expansion method is used. This strategy is more extensive than expanding the hyperbolic tangent series. This approach can produce periodic shock wave solutions such as solitary wave solutions.