Modern Physics Letters B

This paper makes a prospect of the future development in applications of superconducting high-magnetic separation technology to the mining industry with the analysis of domestic status quo of researches and applications in China.

In this paper, design, fabrication and measurements of a novel single-pole-double-throw three-state RF MEMS switch based on silicon substrate are presented. The RF MEMS switch consists of two UV-shaped beam push–pull thermal actuators which have three states of ON, OFF and Deep-OFF by using current actuation. When the switch is at Deep-OFF state, it can provide a higher isolation. The switch is fabricated by MetalMUMPs process. The measurement results show that, to the proposed single-pole-double-throw RF MEMS switch, when Switch I is at the ON state and Switch II is at the OFF state, the return loss is better than −16 dB, the insertion loss of Port1 and Port2 is less than −0.9 dB and the isolation of Port3 and Port1 is better than −22 dB at the frequency range from 8 GHz to 12 GHz. When Switch I is at the ON state and the actuator of Switch II is pulled back, which is called the Deep-OFF state, the return loss of Port1 is better than −15.5 dB, the insertion loss of Port1 and Port2 is better than −0.8 dB, and the isolation of Port3 and Port1 is better than −23.5 dB can be achieved at the frequency range from 8 GHz to 12 GHz.

There are some disadvantages such as low efficiency, high work intensity by using the manual methods to detect the quality of micro-nano parts because of the characteristics such as small size and fragile structure. Considering about the disadvantages, computer microscopic vision is introduced into the detection system in this paper, which can collects the image information of the parts into the computer system efficiently. The parts to be detected are transmitted by the spin material platform driven by the stepping motor. It is CNN based on deep learning that used to detect the surface quality and classify the defects of the parts according to the image information in this paper, which can improve the accuracy of the detection and reduce the work intensity of human compared with not only the traditional manual detection methods but also some edge detection methods that former researchers used.

In order to control the charged jet and deposition area of the glass frit in the electrostatic spray system, the nozzles with/without sleeve-type auxiliary electrode are comparatively studied through simulations and experiments. The influence of the voltage applied on the auxiliary electrode and its diameter is analyzed. According to the vector diagram and the distribution of electric field intensity, the optimal values for the applied voltage and the diameter of the auxiliary electrode are determined for the present work, i.e. 1.5 kV and 6 mm, respectively. The experimental results further demonstrate the nozzle with the auxiliary electrode is much better than the one without the electrode, and under the above optimized condition the charged jet can be well controlled to deposit glass frit film on silicon wafer with a line width of 330 μm, which is much more narrow than the conventional nozzle (without the electrode). This work will offer another good way for better control of the deposition during electrostatic spray process.

With the continuous development of the wireless communication, a device needs to integrate multiple antennas, which will lead to increased volume, increased cost, electromagnetic compatibility problems and increased weight. This paper presents a $M\times N$ reconfigurable antenna array based on RF MEMS switches. The modeling script of $M\times N$ reconfigurable antenna array is written in MATLAB by using MATLAB-HFSS-API. In order to quickly get a switch array with target frequency, genetic algorithm is applied to $M\times N$ reconfigurable antenna array. Taking the $3\times 3$ reconfigurable antenna array as an example, a switch array with the resonant frequency of 3.81 GHz is searched from its 4096 switch arrays. The switch array found by genetic algorithm is 1 1 0 0 1 0 0 1 1 0 1 0. The resonant frequency and S11 parameter of this switch array is 3.81 GHz and −20.96 dB. The search takes 6.77 h and the efficiency is 17 times of the simulating all switch arrays.

A novel chiral metasurface (CMS) based on T-shaped resonators is proposed and investigated numerically. The CMS is composed of a periodic array of bi-layered conjugated fourfold T-shaped structure. The retrieved effective electromagnetic (EM) parameters indicate that the multi-band negative refractive index associated with strong optical activity and circular dichroism (CD) effect is realized in terahertz (THz) region. The physical mechanism is illustrated by analyzing the current density distributions. Due to its exotic chiral optical properties, the proposed CMS is useful for the development of THz devices.

In this paper, we study the nonlinear Schrödinger equation with self-consistent sources, and obtain the rogue wave solution, the breather solution and their interactions by the generalized Darboux transformation. The dynamics of the rogue wave solution, the breather solution and their interactions are analyzed.

Molecular dynamics (MD) simulations were performed to investigate the evolution of local atomic structure during rapid solidification of liquid metal W. The microstructures were characterized by means of potential energy (PE) per atom, pair distribution function and largest standard cluster analysis (LSCA). Instead of [12/555] perfect icosahedra, the [8/555 2/544 2/433] distorted icosahedra dominated in W monatomic metallic glasses (MGs). With the decrease of temperature, these clusters in metal W systems aggregated steeply into icosahedral medium-range orders (IMROs), especially in the super-cooling liquid region. Moreover, the maximal size $n_{max}$ of IMROs played a control role in the formation of W monatomic MGs rather than the number $N_{\mathrm{\text{IMRO}}}$. The mean local fivefold symmetry $D_{\mathrm{\text{S555}}}$ of IMROs was demonstrated to be an effective indicator to characterize the glass transition of monatomic metal W liquids.

In the current experiments, realizing the synthetic spin-orbital coupling (SOC) with ultracold atoms, a finite two-photon detuning (TPD) is present. However, in most relevant theoretical studies so far, the TPD has been assumed as zero. Here, we investigate how a finite detuning affects the ground phase diagram in a Bose gas with equal-weight Rashba and Dresselhuas SOC. We show that the single-particle dispersion relation in the presence of a finite TPD can be significantly modified compared to the case with zero detuning, which gives rise to experimentally observable effects on quantum tricriticality and phase transitions. In particular, the zero-momentum phase that can arise for a zero TPD becomes unstable against a finite TPD and disappears. Our results are relevant to the current cold atom experiments using the Raman laser-induced gauge field.

Exploring new two-dimensional (2D) materials is becoming a peculiarly important task due to their potential applications in future nanoelectronics and optoelectronics. In this paper, we propose a stable 2D monolayer B₆C₂P₂ based on particle swarm optimization (PSO) methodology for crystal structure prediction. The monolayer B₆C₂P₂ is an indirect semiconductor with the band gap of about 1.05 eV. We further find that under a biaxial tensile stress with its strain ratio altering from 6% to 9%, B₆C₂P₂ can be transferred from an indirect semiconductor to a quasi-direct semiconductor. Moreover, it can be transferred to metal until the strain ratio goes up to 15%. These properties promote the monolayer B₆C₂P₂ to be a potential 2D material for future applications in optoelectronic devices and nanodevices.

We analyze guided waves in the linear media separated nonlinear interface. The mathematical formulation of the model is a one-dimensional boundary value problem for the nonlinear Schrödinger equation. The Kerr type nonlinearity in the equation is taken into account only inside the waveguide. We show that the existence of nonlinear stationary waves of three types is possible in defined frequency ranges. We derive the frequency of obtained stationary states in explicit form and find the conditions of its existence. We show that it is possible to obtain the total wave transition through a plane defect. We determine the condition for realizing of such a resonance. We obtain the reflection and transition coefficients in the vicinity of the resonance. We establish that complete wave propagation with nonzero defect parameters can occur only when the nonlinear properties of the defect are taken into account.

Flexoelectricity describes the coupling between polarization and strain gradients and presents a strong size dependence at nanoscale. In the current work, based on the extended linear piezoelectricity theory with flexoelectricity, we study bending of piezoelectric beams with consideration of flexoelectric effect. When a concentrated force at any position and electric voltage is exerted, the expression for bending deflection of simply-supported and clamped beams is derived. The obtained results show that flexoelectric effect can cause a softer elastic behavior of simply-supported and clamped beams. Sensitivity analysis of the transverse deflection and bending moment is made for two typical boundary conditions. Flexoelectric effect has a more significant effect on the bending response of a piezoelectric beam with smaller thickness.

This work studies the hyperbolic nonlinear Schrödinger equation (H-NLSE) in (2 + 1)-dimensions. The model describes the evolution of the elevation of water wave surface for slowly modulated wave trains in deep water in hydrodynamics, and also governs the propagation of electromagnetic fields in self-focusing and normally dispersive planar wave guides in optics. A class of gray and black optical solitary wave solutions of the H-NLSE are reported by adopting an appropriate solitary wave ansatz solution. Moreover, classification of conservation laws (Cls) to the H-NLSE is implemented using the multipliers approach. Some physical interpretations and analysis of the results obtained are also presented.

The power of quantum computing may allow for solving the problems which are not practically feasible on classical computers and suggest a considerable speed up to the best known classical approaches. In this paper, we present the contemporary quantum behaved approach which is based on Schrödinger equation and Monte Carlo method. The three basic steps of proposed technique are also mathematically modeled and discussed for effective movement of particles. The performance of the proposed approach is tested for solving the dynamic nonlinear problem. Experimental results reveal the supremacy of proposed approach for solving the nonlinear problem as compared to other approaches.