Modern Physics Letters B

In this brief review, we studied the development milestones of thin film photovoltaics (PV) made of CdTe, CIGS, CZTS and perovskite materials and expanded the discussion to the application of graphene and nanotube in the architecture of these devices. Thin film solar cells are alternative for Si-based PVs and reached a comparable performance to Si PVs. However, they mostly suffer from instability in device and performance and thus several research groups considered the application of graphene and nanostructure carbon materials as conductive electrodes of such devices. The stability of such devices has been the main barrier on up-scaling the cell to module level despite the performance being beaten 23% so far. For emerging perovskite solar cells, the main approach of the researchers is to protect the perovskite layer from moisture and humidity degradation by bringing the protective layers such as graphene and nanotubes or carbon deviations into the devices structure. It has been revealed that graphene’s excellent heat dissipation and thermal conductivity can reduce the moisture reaction with perovskite layer which promises device stability at air.

Further experimental investigations in the microwave field emerging from a composite pupil are reported in order to determine the nature of the wave propagation. The experiments consisted of delay-time measurements as a function of the distance of the detector from the pupil under test, as well as of the phase variation of a radio-frequency signal at 35 MHz that modulated the same microwave carrier at 9.33 GHz. In addition, measurements employing an admittance comparator were made in order to determine the character of the propagation impedance. All results obtained confirmed superluminal behavior in the near field, up to a distance of about 40 cm. These results were then interpreted within the framework of a stochastic model.

The competitive relationships among ports become complicated as the consequence of the prosperity of international trade. Typical oligopoly competition models cannot be competent for the analysis of ports competition in real scenario. In this paper, the scale-free network is adopted to characterize the interactions among ports with various number of neighbors. For each port node, not only direct competition but also indirect influences exerted by its neighbor are taken into account. Following the hypothesis in evolutionary game theory, social learning behavior among competitors occurs generally in our model. Conforming to reality, strategies considering both price collusion and price competition are proposed to investigate evolutionary dynamics of competition among ports in the self-organization process of imitation. It shows that neighbors have the same goal but play different roles in affecting strategy transition during the evolution with two competitive means. We explore how evolutionary dynamics are influenced by different imitation means. Then this paper verifies that price collusion is more conducive to port development when abundant resources is provided. Our results obtained in this evolutionary framework with different imitation means may enhance port-operation efficiency.

High sensitivity and response ratio of magnetoimpedance (MI) sensors have raised interest for using them in different environments for detection of weak magnetic fields of magnetic elements even though the high dependence of the MI response to the surface condition of the MI sensor has limited its application in some environments. In this study, we investigate the effects originating from the MI measurement in moisturized air. Using scanning electron microscopy (SEM) images, it is observed that the surface of an Fe-based MI sensor has become rough and granular after the presence of moisture on its surface. Results can be useful for developing MI sensors for use in different environmental conditions.

The difference between the optimal current difference and the actual current difference will be used as the correction item. The dynamic multiple current information about the front lattice will be considered. A modified lattice traffic hydrodynamics model is established by considering the downstream traffic conditions in the two-lane system. Through the stability analysis, it is found that the downstream traffic condition can be added as a correction term to increase the stability of the system. The area of the stable region on the phase diagram is enlarged by the derived stability. The mKdV equation, which can describe density wave, is derived by nonlinear analysis. Finally, the phase diagram of stability condition in linear analysis and the kink wave diagram of mKdV equation in nonlinear analysis are obtained by numerical simulation, which verifies the theoretical derivation of this paper. The results show that in the two-lane traffic flow expansion model, considering the downstream traffic conditions can effectively suppress traffic jams and make the traffic flow stable.

In this paper, we investigate an integrable nonlocal “breaking soliton” equation, which can be decomposed into the nonlocal nonlinear Schrödinger equation and the nonlocal complex modified Korteweg–de Vries equation. As an application, with the use of this decomposition and Darboux transformation, the dark solitons, antidark solitons, rational dark solitons and rational antidark solitons of the considered equation are given explicitly. In particular, the interaction mechanisms of these solutions are discussed and illustrated through some figures.

In this work, Fix 1211 addition has been used in different amount in the iron mix. The samples prepared have been used thermically in the temperature 77${}^{\circ }$C in normal atmosphere condition. The samples thermically developed have been thermically analyzed with the constant 5${}^{\circ }$C/min of 20 ml/min argon gas from 30${}^{\circ }$C up to 900${}^{\circ }$C. Thermo-physical mechanisms have been researched in the cement, sand and road metal with the thermogravimetric (TG) and Differential Scanning Calorimetry (DSC) analysis. Mass kinetics, activation energy and special heat capacity have been researched for different temperature intervals. The decomposition mechanism of the mass in stages and the speed of decomposition is equal to the cost of the heat flow. The mass loss has been determined in 6.99 mg under the first code, 5.82 mg under the second code, 5.63 mg under the third code, 4.65 mg under the fourth code in $30\le T\le 900^{\circ }$C temperature interval. In addition, it has been researched that the activation energy has been changed between 0.56–0.80 eV and 0.23–0.36 eV under each code and phase passage.

This study is devoted to handle disturbances occurring in a subway network during the off-peak period. By dissecting the relationship of transfer connections between connected lines, transfer passengers and non-transfer passengers as well as operating agencies are taken into consideration, respectively, and a trade-off method for timetable rescheduling is proposed to minimize the waiting time of all transfer passengers as well as the deviation from the planned timetable. We adopt the $𝜀$-constraint method to convert the bi-objective model to an integer linear programing model with single objective, which can be solved by CPLEX within seconds. The method is validated by some numerical experiments based on a real-world case derived from the Beijing Subway network. Results show that the proposed method is able to generate approximate Pareto optimal solutions and to provide decision support for dispatchers.

The adsorption properties of isolated H₂O molecule on stoichiometric and reduced ceria(111) surfaces are theoretically investigated by first-principles calculations and molecular dynamics simulations. We find that the most stable adsorption configurations form two hydrogen bonds between the adsorbate and substrate. The water molecule is very inert on the stoichiometric surface unless up to a high temperature of 600 K. For the reduced surface, we find that the oxygen vacancy enhances the interaction. Moreover, simulations at low temperature of 100 K confirm that it is facilitated for water to dissociate into H and OH species.

In this paper, the combined heat and mass transfer of mixed convection, non-similar Sisko fluid flow in the presence of a magnetic field is studied. The combined effects of thermal radiation and heat generation/absorption are examined for Sisko fluid flow via local non-similar method. For the radiative heat transfer, Rosseland approximation model is used. The governing partial differential equations of the present problem are transformed into a system of nonlinear ordinary differential equations by employing the Sparrow–Quack–Boerner local non-similarity method (LNM). The obtained equations are then numerically investigated by utilizing the bvp4c function in MATLAB. The impact of different supervising parameters on the velocity, temperature, skin friction and rate of heat transfer is performed graphically. It is observed that the velocity is more for a higher rate of the buoyancy force parameter while it is less for opposing buoyancy fluid. The thermal boundary layer thickness for the shear thickening fluids is smaller than the shear thinning fluids.

To solve the problems of low efficiency and high void rate in the process of the MEMS filter (die) attach and increase the strength of wire bonding between the die and microwave circuit board, plasma cleaning process was introduced in the micro-assembly process of the MEMS filter switch module. The spreading area of the solder melted on the copper was analyzed before and after the plasma cleaning process. Process parameters including plasma flow, radio frequency time and radio frequency power were optimized by the orthogonal test. It is demonstrated that the plasma cleaning process is effective to decrease the void rates in die attach and enhance the wire bonding strength, thus improve the reliability of the MEMS filter module micro-assembly.

This paper focuses on the study of dynamic boundary flow problems based on the Element-Free Galerkin method. First, Navier–Stokes equation is discretized with the Galerkin method. The inertial term in the equation is discretized with the method of the speed term and direct deduction, respectively. The penalty function method is used to deal with the pressure and the essential boundary condition in the equation, and the discretization of two-dimensional N–S equation based on the EFG method is established. However, irregular changes in boundary conditions are often encountered in practical fluid problems. For example, the motion of flapping-foil is not uniform relative to the flow. In this paper, numerical experiments are carried out for the flow problems with non-uniform boundary motions. The problem which a plate with non-uniform drag movement above a rectangular tank filled with water is studied with the EFG method. The feasibility of the proposed algorithm is verified by comparison with the FEM method. Then, the procession of the water in the tank is stimulated. In the end, the influence of different calculation time steps on the accuracy of the solution is discussed.

Metal halide-perovskite solar cells have managed to attain soaring heights in power conversion efficiency in the past decade, rising from 3.8% to around 24% in 2019. Formal lead-based perovskites have captivated massive attention because of their then toxic nature and short-term stability of fabricated devices. Therefore, lead-free perovskites have drawn the researcher’s interest in recent years. In this work, we projected a unique planar perovskite structure constituted of $\mathrm{\text{FTO}}|$ Tungsten Disulfide $({\mathrm{\text{WS}}}_2)|$ lead-free perovskite$\left|{\mathrm{\text{Cu}}}_2\mathrm{\text{O}}\right|\mathrm{\text{Au}}$. Herein, Tungsten Disulfide (WS₂) acts as an electron transport layer (ETL) due to its excellent electron transport capability. The cuprous oxide is used as a hole transport layer (HTL) due to its perfect band alignment with perovskites. The proposed structure is quantitatively analyzed using a solar cell capacitance simulator. The simulation carried out revealed that tin halide perovskite (CH₃NH₃SnI₃) is having the great potential to be an absorbent layer. The proposed configuration demonstrated excellent power configuration efficiency (PCE) of 23% at an optimized thickness of different segments. The impact of neutral defect density and position of defect energy level with respect to active layer on device performance was quantitatively analyzed. The results showed that values of performance parameters ($J_{\mathrm{\text{SC}}}$, FF, $V_{\mathrm{\text{OC}}}$ and PCE) of proposed device configurations are drastically reduced with increasing the total defect density of interfacial and perovskite layers. These simulated results will help the researchers working in the specific area of lead-free perovskite solar cell (LFPSC) fabrication.

This paper investigates the robustness of first-order coherence characterized by the Laplacian spectrum in duplex networks with varying interlayer linking topologies and node connections of two layers under degree, closeness and eigenvector centrality indicators. The interlayer linking weight and linking rate play an important role in the coherence of duplex networks. The increasing larger linking weight and linking rate make the duplex networks more consensus. In addition, the positively, negatively and randomly correlated linking patterns display diverse consensus behaviors in duplex networks with different interlayer connections. Finally, the linking pattern under the eigenvector centrality has a profound impact on the coherence in the constructed duplex networks. The obtained results of duplex networks may help with a deeper understanding of consensus in multilayer networks.