Modern Physics Letters B

Cu₂ZnSnS₄ (CZTS) materials have been widely investigated due to their excellent properties in solar cell applications. The common reference structure for CZTS cells is Al:ZnO(AZO)/i-ZnO/CdS/CZTS, but it is critical to find a suitable buffer layer material to replace toxic cadmium (Cd). In addition, the efficiency of CZTS cells is improved by improving the doping type (n or p) and doping concentration of MoS₂ generated during the manufacturing process. wxAMPS was used to simulate the performance of a CZTS battery with an Al:ZnO/i-ZnO/Zn(O,S)/CZTS/(MoS₂) structure. The performance of batteries using Zn(O,S) and CdS as buffer layers was compared. The optimal thickness of CZTS layer and the doping concentration of CZTS layer were calculated, and the doping type and concentration of MoS₂ layer were analyzed and the performance of the battery was improved by optimizing the solar cell parameters. This work provides novel ideas for designing and manufacturing higher performance solar cells.

The EPR paradox appears when measurement results of some properties of two distantly entangled particles are correlated in a way that cannot be explained classically, and apparently violate locality. The resolution of the paradox depends on one’s interpretation of quantum mechanics. Explanations from quantum mechanics remain commonplace today, but they fail to explain the EPR (Einstein, Podolsky and Rosen) paradox totally in a way than can be accepted by the whole community. Here, we present a simple resolution to this paradox in which the uncertainty in the energy of the two-particle system is reduced by its lack of interaction during the journey so that the uncertainty in time becomes greater than the time they have been separating. Consequently, the present and past become indistinguishable because when we measure an observable in the system its value is the same as if the two particle were still together or very close. It is also argued that the destruction of information as the present and past become identical should release heat by Landauer’s principle, and this might make this proposal testable.

In this paper, we firstly recall some basic facts on the Two-Boson hierarchy. Then, introducing some time variables that consist of a non-abelian Lie algebra. Next, we construct additional symmetries for the Two-Boson hierarchy with the aid of the Orlov–Schulman operator, which depend on the time variables and dressing operator. In addition, we give the additional flow equations of the Two-Boson hierarchy as a simple example, and prove that the additional flows are symmetries of the Two-Boson hierarchy. In this way, an isomorphism between the additional symmetries of the Two-Boson hierarchy and the $W_{\infty }$ algebra is constructed. Finally, the multi-component Two-Boson hierarchy can be defined, and we consider the additional symmetries for the multi-component Two-Boson hierarchy with the method of Dickey, Orlov, and Shulman.

In this paper, we mainly study the symmetry analysis and conservation laws of the time fractional Clannish Random Walker’s Parabolic (CRWP) equation. The vector fields and similarity reduction of the time fractional CRWP equation are obtained. In addition, based on the power series theory, a simple and effective approach for constructing explicit power series solutions is proposed. Finally, by use of the new conservation theorem, the conservation laws of the time fractional CRWP equation are constructed.

The rapid development of new urbanization boosts the pace of urban rail transit (URT) network construction. The new-built lines not only facilitate people’s daily travel, but also change the reliability of the original network. In this paper, based on the complex network theory, the static characteristics of Tianjin URT represented by the current and forward networks are analyzed. The global efficiency is selected as the evaluation index to analyze the evolution characteristics of the network. The results show that Zhigu station and Xiawafang station are more vulnerable in the current network, while Zhangxingzhuang station and Jinzhonghe street station are the key stations in the forward network, and need to be paid more attention. Meanwhile, the lines M9 and Z2 as the key lines in the long-term network and their reliability must be ensured.

The goal of our research is to establish the direction of coronavirus chaotic motion to control corona dynamic by fractal nature analysis. These microorganisms attaching the different cells and organs in the human body getting very dangerous because we don’t have corona antivirus prevention and protection but also the unpredictable these viruses motion directions what resulting in very important distractions. Our idea is to develop the method and procedure to control the virus motion direction with the intention to prognose on which cells and organs could attach. We combined very rear coronavirus motion sub-microstructures images from worldwide experimental microstructure analysis. The problem of the recording this motion is from one point of view magnification, but the other side in resolution, because the virus size is minimum 10 times less than bacterizes. But all these images have been good data to resolve by time interval method and fractals, the points on the motion trajectory. We successfully defined the diagrams on the way to establish control over Brownian chaotic motion as a bridge between chaotic disorder to control disorder. This opens a very new perspective to future research to get complete control of coronavirus cases.

Two photonic crystal fiber (PCF) polarization beam splitters (PBSs) featuring ultra-short length and ultra-high extinction ratios at wavelengths of 1.31 $\mu$m and 1.55 $\mu$m are designed and investigated. Non-silicon materials, such as gallium arsenide (GaAs) and nematic liquid crystal (NLC), are incorporated into the structure to ensure operation of the splitters in the communication bandwidth. Based on the full-vector finite element method (FEM), numerical simulation is carried out to optimize the structural parameters systematically. Specifically, for the splitter operating at 1.31 $\mu$m, the optimal optical fiber length, extinction ratio, and bandwidth are 27.87234 $\mu$m, $-152.40$ dB, and 152 nm, respectively. In comparison, the optimal fiber length, extinction ratio, and bandwidth of the splitter at the wavelength of 1.55 $\mu$m are 15.59356 $\mu$m, $-137.21$ dB, and 200 nm, respectively. The results reveal that the splitters have great potential in environmental monitoring, biochemical detection, and optical communication.

Traffic dynamics of multilayer networks draws continuous attention from different communities since many systems are actually proved to have a multilayer structure. Since the core nodes of network are prone to congested, an effective routing strategy is of great significance to alleviate the congestion of the multilayer networks. In this paper, we propose an efficient improved routing strategy, with which the core nodes that can reasonably avoid congestion at the high-speed layer in the transmission process of packets, and can also make the most of the traffic resources of the low-speed layer nodes to optimize the traffic capacity of multilayer networks. The simulation results show that the proposed routing strategy can not only improve the network traffic capacity, but also shorten the average path length and average transmission time.

A triple mixed-spin Ising system defined on the Bethe lattice is numerically investigated by means of exact recursion relations (ERRs) calculations. The lattice is constituted by three types of magnetic atoms A, B, C with spins $1/2$, $1$, $3/2$ respectively arranged in the form ABCABC. The effects of bilinear exchange and crystal-field interactions as well as those of thermal fluctuations on the order parameters and phase diagrams are thoroughly studied and specified. First-order transitions and tricritical points are present for the coordination number $q=4$ whereas at $q=3$ they are absent. Global compensation phenomena are absent for the magnetic system. Instead, it is shown that it can only occur between the sublattice magnetizations B and C of the system. Several novel kinds of reentrance of the phase boundaries while varying the values of model parameters have been reported.

Considering the many-body quantum dynamics, the pairon Green’s function has been developed via a Hamiltonian that encompasses the contribution of pairons, pairon-phonon interactions, anharmonicities, and defects. To obtain the renormalized pairon energy dispersion, the most relevant Born–Mayer–Huggins potential has been taken into account. The Fermi surface for the representative ${\mathrm{\text{YBa}}}_2{\mathrm{\text{Cu}}}_3{\mathrm{\text{O}}}_{7-\delta }$ high-$T_c$ superconductor has been obtained via renormalized pairon energy relation. This revealed the $v$-shape superconducting gap with a nodal point along $k_x=\pm k_y$ direction. Further, the superconducting gap equation has been derived using the pairon density of states. The developed gap equation is the function of temperature, Fermi energy, and renormalized pairon energy. The temperature variation of the gap equation is found to be in good agreement with the BCS gap equation. Also, this reveals the reduced gap ratio ($2\mathrm{\Delta }(0)/k_B{T}_c\simeq 7.71-7.96$ for ${\mathrm{\text{YBa}}}_2{\mathrm{\text{Cu}}}_3{\mathrm{\text{O}}}_{7-\delta }$) in the limit (5–8) of the reduced gap ratio designated for high-$T_c$ superconductors.

In this paper, we investigate the higher-order modified Korteweg–de Vries (mKdV) equation by using an algebraic method. On the background of the Jacobi elliptic function, we obtain the admissible eigenvalues and the corresponding non-periodic eigenfunctions of the spectral problem in this higher-order model. Then, with the aid of the Darboux transformation (DT), we derive the rogue dn- and cn-periodic wave solutions. Finally, we analyze the non-linear dynamics of two kinds of rogue periodic waves.

We proposed a kind of unit cell composed of simple steel plate structures in this work. A variety of acoustic phenomena including anomalous refraction, asymmetric transmission, acoustic splitting and acoustic focusing were realized by coding the unit cells with different splicing modes. The transformation from plane acoustic wave to vortex acoustic wave was also realized by using the coding method of three-dimensional rotation. This work increased the functionality of the unit cell and provided a method for the design of sub-wavelength acoustic devices.

In order to reveal the operating characteristics of the pumpjet propulsor, standard $k$–$𝜀$, standard $k$–$\omega$, RNG $k$–$𝜀$ and SST $k$–$\omega$ turbulence models were used to conduct steady calculation for the whole flow channels. By comparing the calculation results with experimental data, it was found that the calculation errors were very large in some operating conditions. Therefore, the uncertainty analysis was carried out at all operating conditions of the pumpjet propulsor and the error source was finally determined that it is mainly derived from the model error. Then, the applicability of different turbulence models was analyzed to numerical simulation for the pumpjet propulsor by comparing the internal and external characteristics. It can be seen that the strong turbulent kinetic energy in the guide vane will inevitably cause energy loss, but not necessarily in the impeller. In this area, the increase of turbulent kinetic energy will enhance the mixing and transport of fluids, and the impeller makes the fluids get more energy. In addition, a modified hybrid Reynolds Average Numerical Simulation/Large Eddy Simulation (RANS/LES) model was proposed for unsteady calculation, and the performances, internal flow states and the interaction between the pump and the outer region were further revealed under various conditions of the pumpjet propulsor, which provides some references for predicting accurately and selecting conditions optimally in the future.

The perturbation theory based on the inverse scattering transform is extended to discuss the Toda lattice with corrections. The time evolution of the associated scattering data is given by some summation representations for corrections and eigenfunctions. The perturbation correction of the conservation laws is investigated. The adiabatic approximate solution and its correction are considered.

By using the density functional theory (DFT), we explored ferromagnetic and electronic transport aspects of CaM₂S₄ (M = Ti, Cr) spinels. For both spinels, we used PBEsol generalized gradient approximation (GGA) to investigate structural parameters and noted that studied spinels are good compared with the existing parameters. A novel exchange correlation potential, modified Becke and Johnson (mBJ), was utilized for the investigation of electronic, magnetic and transport aspects because we assure our predicting results of electronic bandgap to be consistent to the experiments. The energy difference between ferromagnetic and nonmagnetic states is calculated to check the structural stability of ferromagnetic state. Further, the calculations of band structures and density of state have been explored to check ferromagnetic nature of semiconductor spinels that was further confirmed on the basis of exchange splitting energy and magnetic parameters. In addition, exchange constants ($N_0\alpha$ and $N_0\beta$) and crystal field energy $(E_{\mathrm{\text{cry}}}=E_{t2g}-E_{\mathrm{\text{eg}}})$ along with magnetic moments were also calculated. Our calculated results of magnetic parameters indicate that these spinels are considered as suitable candidate for spintronic applications. Furthermore, to check the reliability of these spinels in energy storage systems, the electronic transport aspects were calculated in detail.

ZnSc₂Se₄ and CdSc₂Se₄ spinels in cubic phase are analyzed by using ab-initio total energy calculations in order to examine their structure along with optoelectronic and thermoelectric characteristics. We used Perdew–Burke–Ernzerhof (PBEsol) generalized gradient approximation (GGA) to evaluate the structural parameters and found that our predicted parameters are good compared with existing other theoretical and experimental results. In addition, we employed the recently developed modified Becke and Johnson (mBJ) potential for the prediction of accurate electronic bandgap measurements of ZnSc₂Se₄ and CdSc₂Se₄. By employing mBJ potential, direct bandgap nature of studied spinels is absorbed from electronic band structure plots, which indicate that bandgap decreases as cation Zn is replaced by Cd. Predicted values of bandgap are $Eg=1.2$ eV for ZnSc₂Se₄ and $Eg=0.8$ eV for CdSc₂Se₄ using mBJ potential representing the studied spinels which play a vital role in the field of opto-electronic devices operating in visible range of spectrum. On the basis of direct bandgaps nature, we also investigate optical characteristic in detail as a function of incident photon energy (0–12 eV). Further, electronic transport characteristic of studied spinels is also investigated with respect to temperature (K) and chemical potential (eV) for their application in energy storage devices.