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This paper is concerned with the propagation dynamics of a three-species nonlocal dispersal predator–prey system with two weak competing aborigine preys. Precisely, our main concern is the invading process of an alien predator into the habitat of two aborigine preys, when two preys are weak competitors in the absence of predator. This invasion process can be characterized by the spreading speed of the predator as well as the traveling wave solutions connecting the predator-free state to other states. First, by applying Schauder’s fixed point theorem with the help of two pairs of upper and lower solutions, we prove that there exists a positive number c∗, when the wave speed is large than or equals to c∗, the system admits a traveling wave solution connecting the predator-free state to the co-existence state, which indicates the occurrence of invasion-coexistence phenomenon. Then the invading speed of the predator is investigated by using the comparison argument. Our results show that (i) the weak interspecific competition between two preys will not affect the phenomenon of invasive-coexistence; (ii) the invading speed of the predator coincides with the minimal wave speed c∗. [ABSTRACT FROM AUTHOR]

The elastic properties, electronic structure, and optical properties of X (X = B , Al, Ga) atomic substitution for arsenene are calculated based on density functional theory. The results show that, at the same concentration, B-substituted arsenene shows the best structural stability, followed by Ga-substituted arsenene, with Al-substituted arsenene being the least. Arsenene and its substitution systems possess excellent mechanical stability. The substitution of X atoms leads to a reduction in the bulk modulus, shear modulus, and Young's modulus of arsenene systems, while simultaneously increasing the Poisson's ratio. For the substitution systems, the four parameters all gradually increase as the substitution concentration increases. The substitution of X (X = B , Al, Ga) atoms into arsenene can facilitate the transformation from an indirect to direct bandgap (except for Al and Ga substitution at a concentration of 3.13%) with a narrower bandgap for increasing substitution concentration. The B–As bond shows the strongest covalency, followed by the Ga–As bond, while the Al–As bond exhibits the strongest ionicity. Arsenene substituted with X atoms shows anisotropy of optical properties in both the xy-plane and along the z-axis direction. The static dielectric constant increases with higher substitution concentration. The imaginary part of the dielectric function shows the extent of excited electron transitions between bands. After X atom substitution, arsenene exhibits a redshift in its absorption edge, which is wider with the higher substitution concentrations. The peak reflectance and valley transmittance values of arsenene and its substitution systems are located in the ultraviolet region in both xy-plane and z-axis. [ABSTRACT FROM AUTHOR]

In this paper, we mainly investigate the dynamics of traveling wavefronts for a model describing host tissue degradation by bacteria. We first establish the existence of spreading speed, and show that the spreading speed coincides with the minimal wave speed of traveling wavefronts. Moreover, a lower bound estimate of the spreading speed is given. Then, we prove that the traveling wavefronts with large speeds are globally exponentially stable, when the initial perturbation around the traveling wavefronts decays exponentially as x → − ∞ , but the initial perturbation can be arbitrarily large in other locations. The adopted methods are the weighted energy and the squeezing technique. [ABSTRACT FROM AUTHOR]

In this paper, the effects of the thermostability, band structure, and the external electric field on the electronic structure of MoSe2/Arsenene heterojunction are calculated based on the density functional theory. The calculation results show that the MoSe2/Arsenene heterojunction is a type-II heterojunction with a bandgap of 0.89 eV. When MoSe2 and arsenene combine by van der Waals force, the electrons are transferred from MoSe2 to arsenene, the holes are transferred from arsenene to MoSe2, with the direction of the internal electric field from MoSe2 to arsenene. The MoSe2/Arsenene heterojunction with valence band top and conduction band bottom contributed by arsenene and MoSe2, respectively, shows excellent thermostability at room temperature. The external electric field can effectively modulate the electronic structure of heterojunction. When the electric field is negative, electrons are transferred from MoSe2 to arsenene and holes from arsenene to MoSe2. The Fermi level of arsenene moves down while that of MoSe2 moves up. When the electric field is positive, the direction of electron and hole transfer are opposite to that when the electric field is negative. The Fermi energy level of arsenene and MoSe2 also move in the opposite direction. [ABSTRACT FROM AUTHOR]

The rapid growth of suspension bridges' span makes vortex-induced vibration (VIV) appears more and more frequently, and once it occurs the closure of the bridge results in considerable economic losses. Investigating the dynamic behavior of the bridge experiencing VIV and the vehicles running on it is thus imperative for providing a reliable guidance for the managers to make operation decisions. Nevertheless, most of the existing studies focus on VIV of bridges subjected to smooth winds, but a certain level of turbulence always exists in reality. The effects of turbulence on vortex-induced dynamic response of the bridge and ride comfort of the vehicles are not clear. This study thus develops a coupled vortex-vehicle-bridge system applicable to the multi-mode lock-in regions of a twin-box deck subjected to both vortex-induced forces and buffeting forces in a turbulent flow. The system is then applied to a real long suspension bridge with three types of vehicles subjected to either smooth or turbulent winds. The results from the case study show that the increasing turbulence mitigates vortex-induced responses of both the bridge and the vehicles and reasonably improves the vehicles' ride comfort. However, the buffeting forces induced by turbulent wind component should not be ignored when turbulence intensity becomes high. [ABSTRACT FROM AUTHOR]

In this paper, for the Allen–Cahn equation, we obtain the error estimate of the temporal semi-discrete scheme, and the fully-discrete finite element numerical scheme, both of which are based on the invariant energy quadratization (IEQ) time-marching strategy. We establish the relationship between the L 2 -error bound and the L ∞ / H 2 -stabilities of the numerical solution. Then, by converting the numerical schemes to a form compatible with the original format of the Allen–Cahn equation, using mathematical induction, the superconvergence property of nonlinear terms, and the spectrum argument, the optimal error estimates that only depends on the low-order polynomial degree of − 1 instead of e T / 2 for both of the semi and fully-discrete schemes are derived. Numerical experiment also validates our theoretical convergence analysis. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of traveling wavefronts for a three-component Lotka–Volterra system with nonlocal dispersal. This system arises in the study of three-species competition model in which there is no competition between two of these three species. It has been shown that this system admits a bistable traveling wavefront. In this paper, we further investigate the stability of bistable traveling wavefronts. By constructing suitable super- and sub-solutions and using a dynamical system approach, we obtain the globally asymptotic stability of the bistable traveling wavefronts. [ABSTRACT FROM AUTHOR]

In this paper, we study the linear determinacy of the minimal speed of traveling wavefronts for a three-component competition system with nonlocal dispersal. We first transform this system into a cooperative system. Then, by constructing suitable upper solutions, we give some general conditions to ensure the linear determinacy of the minimal speed. Finally, we provide some more precise conditions that only rely on the parameters of the system such that the linear determinacy of the minimal speed is assured. [ABSTRACT FROM AUTHOR]

The ellipsoidal magnetization model has a wide range of application scenarios. For example, in aviation magnetic field prospecting, mineral prospecting, seabed prospecting, and UXO (unexploded ordnance) detection. However, because the existing ellipsoid magnetization formula is relatively complicated, the detection model is usually replaced by a dipole. Such a model increases the error probability and poses a significant challenge for subsequent imaging and pattern recognition. Based on the distribution of ellipsoid gravity potential and magnetic potential, the magnetic anomaly field distribution equation generated by the ellipsoid is deduced by changing the aspect ratio, making the ellipsoid equivalent to a sphere. The result of formula derivation shows that the two magnetic anomaly fields are consistent. This paper uses COMSOL finite element software to model UXO, ellipsoids, and spheres and analyzes magnetic anomalies. The conclusion shows that the ellipsoid model can completely replace the UXO model when the error range of 1nT is satisfied. Finally, we established two sets of ellipsoids and calculated the magnetic anomalous field distributions on different planes using deduction formulas and finite element software. We compared the experimental results and found that the relative error of the two sets of data was within ± 0. 2 5 ‰. Error analysis found that the error distribution is standardized and conforms to the normal distribution. The above mathematical analysis and finite element simulation prove that the calculation method is simple and reliable and provides a magnetic field distribution equation for subsequent UXO inversion. [ABSTRACT FROM AUTHOR]

The electronic and optical properties of black phosphorene with different bent angle are studied using density functional theory based on the first-principles. Within the scope of our study, it was found that the phosphorene becomes less stable with the increasement of bending deformation. Bending deformation has great impact on the electronic and optical properties on phosphorene. The bandgap degrades a little at 2. 5 ∘ bent angle, and then increases when the bent angle does not surpass 1 5 ∘ , after which the bandgap decreases with the increasement of bending deformation. Besides, the bandgap of black phosphorene occurs a direct to indirect transition at 1 9 ∘ bent angle. The bandgap calculated by HSE06 is larger than PBE functional, but the law of changes is consistent. By analyzing the density of states, we concluded that all the undeformed and deformed phosphorene structures have a strong sp orbital hybridization. Besides, the p orbits have narrower gap than s orbits, which causes the narrower bandgaps of these structures. From the analysis of optical properties, we concluded that the black phosphorene with 7. 5 ∘ bent angle has the highest absorption coefficient. All structures under bending deformation have higher reflectivity peak than intrinsic black phosphorene, among these structures, the black phosphorene with 2 7. 5 ∘ bent angle has the highest reflectivity. The novel optical property is observed at the 2 0 ∘ deformed structure, it stops absorbing (reflecting) light first. Redshift and blueshift phenomena are observed at the highest absorption peak and reflectivity peak. [ABSTRACT FROM AUTHOR]

In this paper, the dissipative characteristics of unsteady heat conduction process for the one-dimensional sphere is studied. The dissipation function can be regarded as a Lyapunov function for the heat conduction system, which determines the evolution direction of the system and the stability of the steady state. By use of the vector formula, the relationship between the thermal potential and dissipation function is derived, and its similarity with the dissipation system of mechanical energy is shown. The expression of dissipation function is obtained when the boundary temperature is fixed. In addition, an example for optimization of heat conduction process is discussed based on the entransy dissipation extremum principle. [ABSTRACT FROM AUTHOR]

The CrCuFeMnNi high entropy alloy (HEA) powder was synthesized by mechanical alloying. The effects of milling time and subsequent annealing on the structure evolution, thermostability and magnetic property were investigated. After 50 h of milling, the CrCuFeMnNi HEA powder consisted of a major FCC phase and a small amount of BCC phase. The crystallite size and strain lattice of 50 h-ball-milled CrCuFeMnNi HEA powder were 12 nm and 1.02%, respectively. The powder exhibited refined morphology and excellent chemical homogeneity. The supersaturated solid solution structure of the as-milled HEA powder transformed into FCC1, FCC2, a small amount of BCC and ρ phase in annealed state. Most of the BCC phase decomposed into FCC (mainly FCC2 phase) and ρ phases, and the dynamic phase transition was almost in equilibrium at 900 ∘ C. The saturated magnetization and coercivity force of the 50 h-ball-milled CrCuFeMnNi HEA powder were respectively 16.1 emu/g and 56.2 Oe. Phase transition of supersaturated solid solution structure of the as-milled CrCuFeMnNi HEA powder occurred at annealed condition of 700∼900∘C. FCC phase completely transformed into FCC1 and FCC2 phases. However, most of the BCC phase decomposed into FCC (mainly FCC2 phase) and ρ phase (Cr5Fe6Mn8), and the dynamic phase transition was almost in equilibrium at 900∘C. [ABSTRACT FROM AUTHOR]

The structure of ZrB2 under high-pressure was predicted by Particle Swarm Optimization method (CALYPSO). We investigated the structure stability, phonon dispersion curve, elasticity, electronic structure and thermodynamic properties of ZrB2 under high-pressure and high-temperature via first-principles calculations. It maintained the hexagonal structure when the pressure lowers below 600 GPa at 0 K, which is confirmed by the calculated phonon dispersion curve. Studies indicate that the elastic modulus and Poisson’s ratio increase monotonically with pressure, as supported by some theoretical and experimental evidences. Calculated anisotropic factors demonstrate that compression and shear isotropy of ZrB2 weakens as the pressure increases. Using the quasi-harmonic approximation Debye model, the Debye temperature, sound velocity, expansion coefficient, thermal capacity under the high-temperature and pressure were also predicted. [ABSTRACT FROM AUTHOR]

Internal flow field characteristics of HDDs are usually influenced by the arm swing during seek operations. This, in turn, can affect aerodynamic noise and airflow-induced noise. In this paper, the dynamic mesh method is used to calculate the flow-induced vibration (FIV) by transient structure analysis and the boundary element method (BEM) is utilized to predict the vibration noise. Two operational states are considered: the arm is fixed and swinging over the disk. Both aerodynamic noise and vibration noise inside drives increase rapidly with increase in disk rotation and arm swing velocities. The largest aerodynamic noise source is always located near the arm and swung with the arm. [ABSTRACT FROM AUTHOR]

The heat currents and thermal rectification in a non-equilibrium spin-chain system with multi-spin interaction and external field are investigated. The influence of system parameters, including mean temperature, temperature difference, external field and multi-spin interaction, on heat currents and thermal rectification are studied. We show that the magnitude of heat currents and thermal rectification can be controlled by varying these parameters. Particularly, by increasing the intensity of multi-spin interaction and external field, two kinds of blockade phenomena can be observed, i.e. the thermal blockade and the energy blockade. Besides, the physical origin of thermal rectification and the blockade phenomena are explored. In addition, the present results may provide a useful approach to the controlling of heat currents when there exists multi-spin interaction in the system. [ABSTRACT FROM AUTHOR]

Vertical silicon nanowire (SiNW) platforms are candidates for use in ultrasensitive biosensors, with surface-to-volume ratio higher than one-dimensional SiNW. In this paper, a vertical SiNW electrolyte-insulator-semiconductor (EIS) structure with an ALD-HfO2 sensing membrane is proposed for use in a hydrogen ion sensor. Hafnium dioxide is used as the sensing membrane, which was deposited on the surface of the vertical SiNW structure by atomic layer deposition. The sensing properties were examined using a HP4284A high-precision LCR analyzer. A linear relationship was found between the flatband voltage shift and the hydrogen ion concentration. Comparing with different diameters of SiNW, the sensitivity with diameter of 200 nm was slightly higher than 100 nm. A post-deposition rapid thermal annealing (RTA) was utilized to optimize the sensing properties, and the sensitivity was increased to 51.07 mV/pH. [ABSTRACT FROM AUTHOR]

With the effects of Dzialoshinski–Moriya interaction and external magnetic field, the entanglement transfer has been investigated in a parallel spin-chain system. Our results imply that the perfect transfer can be realized at some special times, and the transfer time can be greatly condensed with the rising of the spin-orbit coupling strength. The entanglement sudden death phenomenon is sensitive to the initial condition. In addition, due to the application of magnetic field on the channel spins, the reliability and efficiency of the transmission are greatly challenged. [ABSTRACT FROM AUTHOR]

This research is aimed on reversing multidrug resistance (MDR) of chemotherapy in lung cancer. According to our previous research, chemotherapeutic drugs resistance in lung cancer is mainly due to high expression of multidrug resistance-associated protein (MRP) gene and activation of caspases. The effect of stephania tetrandra-containing Chinese herbal formula, namely Supplement Energy and Nourish Lung (SENL), is effective in enhancing efficacy and reducing toxicity of chemotherapy in lung cancer. However, the underlying mechnism is largely unknown. To understand whether and how SENL herbs function on multidrug-resistance lung cancer cells, we treated a multidrug resistance lung cancer cell line, SW1573/2R120 with SENL herbs alone or together with a chemotherapeutic drug, Adriamycin (ADM). We observed that SENL herbs had a significant synergistic effect with ADM in inhibiting the growth of SW1573/2R120 cells. SENL alone and particularly together with ADM could significantly increase cell apoptotic death via mitochondria- and caspase-dependent pathway. Furthermore, we showed that SENL herbs could reverse drug resistance of lung cancer cells by decreasing MRP expression and increasing accumulation of intracellular ADM, which in turn increase the sensitivity of cancer cells to ADM. Taken together, the mechanism underlying reversal effect of drug resistance by SENL treatment was reported here and further systematical investigation on SENL herbs may lead to solve drug resistance in lung cancer chemotherapy. [ABSTRACT FROM AUTHOR]

We present a scheme of remote preparation of the two-particle state by using two Einstein–Podolsky–Rosen pairs or two partially entangled two-particle states as the quantum channel. The probability of the successful remote state preparation is obtained. [ABSTRACT FROM AUTHOR]

The afterpulse probability has been measured using the photon statistical method on the base of theoretical analysis for single-photon detection. It is found that the measured afterpulses obey Gaussian distribution, and the Gauss curves are left shifted with increasing incident photon intensity. We have analyzed the physical process of the phenomenon and obtained the afterpulse probability of our single-photon detector. Compared with the common start–stop method, this robust photon statistical method has the advantages of direct measurement and not requiring additional equipment. [ABSTRACT FROM AUTHOR]

The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations, X-ray photoelectron spectroscopy (XPS), mechanical property tests, UV spectroscopy, and light microscope. The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) samples show that the three colorants can decrease the efficiency of photo-initiated crosslinking of polyethylene to some different degree, in which the effect of red colorant is the largest among the three colorants. The colorized samples of 1 mm thickness are easily to be crosslinked to a satisfactory gel content of about 70% by the MWE lamp and optimized reaction conditions, such as the concentration of colorant, irradiation time, and so on. The XPS results give the evidence that the colorants can accelerate the surface photo-oxidation during the photo-crosslinking of polyethylene. The photo-oxidation products such as -CH2-O- and -C(C=O)- groups on the surface of XLPE samples with the colorants apparently increase with increasing the irradiation time. The data from the mechanical tests show that the colorants reduce the tensile strength and improve the elongation at break of XLPE samples. All the above results show that the effects of the three colorants on photo-initiated crosslinking and photo-oxidative degradation decrease with the order of red > blue > green colorants. The light microscope photos show that the colorant can disperse well in PE resin. The mechanism of the colorant effects can be elucidated by comparison of the UV absorption spectra of photo-initiator and colorants. This is because the colorants absorb the same UV wavelength regions as photo-initiator, and thus decrease the photo-crosslinking efficiency of photo-initiator and accelerate the surface photo-oxidation of XLPE materials. [ABSTRACT FROM AUTHOR]

We examine in terms of exact solutions of the time-dependent Schrödinger equation, the quantum tunnelling process in Bose–Einstein condensates of two interacting species trapped in a double well configuration. Based on the two series of time-dependent SU(2) gauge transformations, we diagonalize the Hamilton operator and obtain analytic time-evolution formulas of the population imbalance and the berry phase. The particle population imbalance $\langle\hat{a}^{+}_{L}\hat{a}_{L}-\hat{a}^{+}_{R}\hat{a}_{R}\rangle$ of species A between the two wells is studied analytically. [ABSTRACT FROM AUTHOR]

Quantum dynamics time evolution of a molecular magnet Fe8 interacting with an electron nuclear spin is studied by solving the time-dependent Schrödinger equations. It is found that the variation of Fe8 magnetization and the nuclear spin crucially depends on the interaction strength. The time evolution of the entanglement between the injecting electron and Fe8 is evaluated. It is observed that the entanglement oscillates in time and is tightly related to the spin variation of the injecting electron. From these characteristics, the technique for the reversing and read-out of Fe8 spin states is suggested. [ABSTRACT FROM AUTHOR]

By means of the measure of entanglement called "concurrence" we study the entanglement in Heisenberg dimer single molecular magnets V[SUP4+] with a strong magnetic field and find that thermal entanglement exits for both ferromagnetic (FM) and antiferromagnetic (AFM) cases. In FM case entanglement vanishes for anisotropic parameter λ = 0 while in AFM case, entanglement exits in the whole region of anisotropic parameter 0 ≤ λ ≤ 1. Entanglement variations with anisotropic parameter λ, magnetic field B and temperature T are evaluated. We find a critical magnetic field at which the concurrence changes sharply from zero to maximum entanglement. [ABSTRACT FROM AUTHOR]