Modern Physics Letters B

In the present work, we performed a theoretical work to investigate how a make-to-order (MTO) company operates its producing plan for dealing with a rush-order-inserting problem. Firstly, we constructed two models, the time-minimized and cost-minimized model, to investigate the energy-cost generated by the prey during experiencing the pursuit-evasion game. Inspired by the natural pursuit-evasion game, two models have been extended and re-constructed to understand the cost of MTO company induced by the rush-order-inserting problem. In particular, the present results revealed that the optimal strategy adopted by the prey and the MTO manager are significantly coincident. This work provides helpful findings for operating the rush-order-inserting problem and indicates the natural behavior can be appropriately adopted to guide the manager’s decision making.

This paper examines the effectiveness of an integration scheme, which called the extended modified auxiliary equation mapping method in exactly solving a well-known non-linear longitudinal wave equation with dispersion caused by transverse Poisson’s effect arises in a magneto-electro-elastic (MEE) circular rod. Explicit new exact solutions are derived in different form such as hyperbolic, kinky, anti-kinky, dark, and singular solitons of the longitudinal wave equation. The movements of obtained solutions are shown graphically, which helps to understand the physical phenomena.

This paper presents results of density functional theory (DFT) studies on structural, electronic, and magnetic properties of novel Y₂FeSi Heusler material characterized by spin polarization at Fermi level of $\sigma =79.3\%$ and magnetic moment of 1.56 ${\mu }_B$. The total magnetic moment of investigated material is dominated by Iron sites, while magnetic moments coming from Yttrium sites are aligned antiparallel to the Iron. Here, we introduced Co and Mn substitutions to alter the magnetic and electronic properties of the studied material. The Heusler alloys are very sensitive to electronic structure changes induced by ionic substitutions, which allowing to specifically modulate their properties. The Co-substitution lowered the total magnetic moment to $\sim$1.20 ${\mu }_B$ and Mn caused a rise to $\sim$1.93 ${\mu }_B$. Introduction of Mn resulted in $\sigma =86.5\%$ spin polarization. We hope that this study will promote further theoretical as well as experimental interest in these types of compounds.

In this study, a design for the high-efficiency transmissive terahertz polarization beam splitter is proposed. Based on the metal–insulator–metal waveguide array structure, it is found that the phase change between the transverse-electric (TE) and transverse-magnetic (TM) modes of terahertz wave transmission depends greatly on the medium width. According to this phenomenon, our designed devices can achieve polarization splitting of TE and TM modes in the frequency range 0.8–2.4 THz, and the transmittance can be maintained above 85%. In addition, through judicious design, polarization splittings with 93% transmittance at 1 THz and 95% transmittance at 1.5 THz are obtained, and polarization splitting at different angles is achieved according to variable periods. Compared with the traditional polarization beam splitter, this design has the advantages of adjustable frequency, high efficiency, and easy integration, thus having potential application in terahertz optical systems.

Formation of embedded Co nanostructures in Cu(001) surface under electromigration is investigated on the atomic scale by performing self-learning kinetic Monte Carlo (kMC) simulations. The analysis of simulation results reveals the following important result. The electromigration of vacancies does not influence on the self-organization of Co nanostructures in the first layer of Cu(001) surface at all values of current density, which can be achieved in experiments.

In this paper, the microscopic electronic structure and related optical properties of the 4H-SiC (111) surface doped with B, Al, Ga elements are explored by first principles calculation methods. Compared with Al- and Ga-doped systems, the formation energy of B-doped system is found to be very small, showing excellent stability. The bandgaps of doped system decrease obviously, and an indirect bandgap is observed in all the systems. Charge density difference maps show that the covalency is increased after B doping and the iconicity is increased after Al and Ga doping. Moreover, due to the sharp increase in static dielectric constant and dielectric loss, the B-doped system can be used as the candidate for absorbing materials. In addition, the increase in the peak value of the absorption and reflectivity makes the doped systems more promising in the development of solar cells.

The Korteweg–de Vries (KdV)-type bilinear equations always allow 2-soliton solutions. In this paper, for a general KdV-type bilinear equation, we interpret how the so-called extended homoclinic orbit solutions arise from a special case of its 2-soliton solution. Two properties of bilinear derivatives are developed to deal with bilinear equation deformations. A non-integrable (3+1)-dimensional bilinear equation is employed as an example.

Interface capturing methods are effective means to analyze the micromechanism of cavitation. It is complex to handle the phase change for interface capturing methods since it occurs at the narrow gas–liquid interface. This study proposes a new method to handle the phase change: treating it as the source of vapor inside the bubble. The phase change rate is calculated by the constant-transfer model, and the gas phase is an ideal mixture of non-condensable gas and vapor. In the validation part, the cavitation of a spherical bubble is trigged by the Gaussian pulses and harmonic forcing pressure is simulated, which shows good agreements between the proposed model and the constant-transfer model.

Elements in whole blood and urine were determined, and the influence of matrix spectral interference on the analysis results was evaluated in search of optimal measurement conditions on the quadrupole mass spectrometer with inductively coupled plasma Agilent 7700 that did not require correction when determining the varied elements in physical properties. The study showed that when using a quadrupole mass spectrometer, the detection limit of gallium in the studied biological fluids (both whole blood and urine) will be determined not by the background content of the element, but by the interfering effect of ions formed by the matrix components of the analyzed samples.

A mean field antiferromagnetic model with both short and long interaction was studied via the microcanonical approach. The thermodynamic quantities such as temperature and entropy were calculated theoretically. The ergodicity breaking and negative heat capacity could be encountered in this system.

The perovskite membrane with large particle size, uniform coverage and high quality is the prerequisite for the preparation of efficient and stable perovskite solar cells. Various additives have been used to increase the grain size and improve the film morphology and crystal quality. In this paper, methylammonium chloride (MACl) was proposed to obtain high crystalline quality of ${({\mathrm{\text{FAPbI}}}_3)}_{0.85}{({\mathrm{\text{MAPbBr}}}_3)}_{0.15}$ perovskite absorption layer. The results show that the adding ammonium methyl chloride into the precursor of tricationic perovskite not only passivates surface defects to form high-quality and large-grain perovskite films, but also facilitates the formation of pure $\alpha$-phase ${\mathrm{\text{FAPbI}}}_3$. Meanwhile, the designed perovskite precursor solutions were used to fabricate mesoporous perovskite solar cells (PSCs). Owing to the perovskite layer consisting of optimized MACl doping, the short-circuit current density $(J_{\mathrm{\text{sc}}})$ of PSCs reaches 23.81 mA/cm², which is 2.73 mA/cm² higher than the primary ${({\mathrm{\text{FAPbI}}}_3)}_{0.85}{({\mathrm{\text{MAPbBr}}}_3)}_{0.15}$ based on PSCs. The obtained power conversion efficiency (PCE) increases from 13.67% to 17.59%.

Two integrable discretizations of general differential-difference coupled Volterra equations with multiple branches of dispersion are constructed using the Hirota bilinear formalism. The multi-soliton solutions are built and discussed for both discretizations and the nonlinear forms of completely discretized Volterra system are recovered.

Studying overlapping community structure can help people understand complex network. In this paper, we propose a link community detection method combined with network pruning and local community expansion (NPLCE). Firstly, we delete unattractive links and transform pruned graph into line graph. Secondly, we calculate score matrix on line graph through pagerank algorithm. Then, we search seed nodes and expand local communities from the seed nodes. Finally, we merge those communities and transform them back into node communities. The experiment results on several real-world networks demonstrate the performance of our algorithm in terms of accuracy.

The 400 keV proton implantation with a fluence of $8.0\times 10^{16}$ ions/cm² was applied on the ${\mathrm{\text{Er}}}^{3+}/{\mathrm{\text{Yb}}}^{3+}$ co-doped phosphate glass to fabricate a planar waveguide structure. The mode profile at the end face of the waveguide was measured by the end-face coupling technique. The energy loss profile of the energetic protons was calculated by the SRIM 2013. The refractive index distribution was simulated by the reflectivity calculation method. Based on these results, the formation theory of the planar waveguides was discussed through simulating the energy loss distribution and analyzing the reconstructed refractive index profile, which could be used for applications in the future integrated optical systems.

The porous media model was improved to simulate the flow field of a shell-tube heat exchanger with spiral bend tubes. The improved porous medium model can be used to control the fluid flow direction. On the tube side, the streamline was along the spiral bend tubes. The fluid velocities and pressure drops on the tube and shell sides agree well with the experimental values. The fluid flow on the shell side is little affected by the spiral bend structure. The thermal stress of the spiral bend tubes was analyzed. The thermal stress of the spiral bend tubes is much smaller than the thermal stress of the straight tube. The thermal stress at the bend part decreases with the increase of bending angles.

In this paper, the magnetostriction and stress of an orthotropic mechanical high-temperature superconducting disk with a concentric small hole are investigated based on the exponential model of the critical state. Approximate solutions of the displacement and stress for the superconducting disk during zero-field cooling (ZFC) and field-cooling (FC) processes are obtained. The results show that tensile stresses will appear in the disk during the decreasing field of ZFC, while the stresses are always compressive during the increasing field of ZFC and FC processes. This indicates that the superconducting disk is easily damaged during the decreasing field of ZFC and FC processes. The critical point where tensile stress is largest is provided. The value of magnetostriction depends on the size of the disk, the applied field and the magnetization process. This research is helpful in the reliability design of high-temperature superconducting disks and cables with high strength for space solar power stations.