Effects of non-Gaussian noise on the dynamical properties of a logistic system

The dynamical properties of a tumor cell growth system described by the logistic system with coupling between non- Gaussian and Gaussian noise terms are investigated. The effects of the nonextensive index q on the stationary properties and the transient properties are discussed, respectively. The results show that the nonextensive index q can induce the tumor cell numbers to decrease greatly in the case of q 〉 1. Moreover, the switch from the steady stable state to the extinct state is speeded up as the increases of q, and the tumor cell numbers can be more obviously restrained for a large value of q. The numerical results are found to be in basic agreement with the theoretical predictions.     

Effects of fractal gating of potassium channels on neuronal behaviours

The classical model of voltage-gated ion channels assumes that according to a Markov process ion channels switch among a small number of states without memory, but a bunch of experimental papers show that some ion channels exhibit significant memory effects, and this memory effects can take the form of kinetic rate constant that is fractal. Obviously the gating character of ion channels will affect generation and propagation of action potentials, furthermore, affect generation, coding and propagation of neural information. However, there is little previous research on this series of interesting issues. This paper investigates effects of fractal gating of potassium channel subunits switching from closed state to open state on neuronal behaviours. The obtained results show that fractal gating of potassium channel subunits switching from closed state to open state has important effects on neuronal behaviours, increases excitability, rest potential and spiking frequency of the neuronal membrane, and decreases threshold voltage and threshold injected current of the neuronal membrane. So fractal gating of potassium channel subunits switching from closed state to open state can improve the sensitivity of the neuronal membrane, and enlarge the encoded strength of neural information.     

Preparation of the W State of Atoms in a Single Cavity or N Distant Cavities by Photon Interference

We suggest two schemes to generate the W state of N A-type three-level atoms. In the schemes, identical N three-level atoms are trapped in a cavity or N distant cavities. The success or failure of the generation of the W state can be determined by detecting the polarization of photon leaking out of the cavity. The result demonstrates that the W state is free from both the cavity loss and the spontaneous emission due to the fact that the two ground states (left and right) of the three-level atoms are stable states (or metastable states).     

Structures and Electronic Properties of CuN （N≤13） Clusters

A systematic study on the structures and electronic properties of copper clusters has been performed using the density functional theory. In the calculation, there are many isomers near the ground state for small copper clusters. Our results show that the three-dimensional isomers of copper clusters start from Cu7 cluster and then show a tendency to form more compact structures. The results of the formation energy and the second derivative of binding energy with duster size show that besides N = 8, N =11 is also a magic number. Furthermore, it is the first time to find that the ground state of 11-atom clusters is a biplanar structure as same as the 13-atom cluster. The clear odd-even alternation as cluster size for the formation energy indicates the stability of electronic close shell existed in the range studied.     

Step instability of the surface during Ino.2Gao.sAs （001） annealing

Anisotropic evolution of the step edges on the compressive-strained In0.2Ga0.8As/GaAs（001） surface has been investigated by scanning tunneling microscopy （STM）. The experiments suggest that step edges are indeed sinuous and protrude somewhere a little way along the [110] direction, which is different from the classical waviness predicted by the theoretical model. We consider that the monatomic step edges undergo a morphological instability induced by the anisotropic diffusion of adatoms on the terrace during annealing, and we improve a kinetic model of step edge based on the classical Burton Cabrer-Frank （BCF） model in order to determine the normal velocity of step enlargement. The results show that the normal velocity is proportional to the arc length of the peninsula, which is consistent with the first result of our kinetic model. Additionally, a significant phenomenon is an excess elongation along the [110] direction at the top of the peninsula with a higher aspect ratio, which is attributed to the restriction of diffusion lengths.     

Zero-Magnetic-Field Spin Splitting of Polaron＇s Ground State Energy Induced by Rashba Spin-Orbit Interaction

We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit （SO） coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron area/density and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the polaron are more stable than electron＇s.     

Density Matrix and Squeezed Vacuum State for General Coupling Harmonic Oscillator

By taking a unitary transformation approach, we study two harmonic oscillators with both kinetic coupling and coordluate coupling terms, and derive the density matrix of the system. The results show that the ground state of the system is a rotated two single-mode squeezed state.     

Rotational and Vibrational Temperatures of Atmospheric Double Arc Argon-Nitrogen Plasma

The spectroscopic technique is employed to study the emission of atmospheric argon-nitrogen plasma jet generated by an original dc double anode plasma torch. The molecular bands of the N^＋2 first negative system are observed at the torch exit and chosen to evaluate the rotational and vibrational temperatures in comparison with the simulated spectra. The excitation temperature （Texc ≈ 9600 K） is determined from the Boltzmann plot method. The results show that the rotational, vibrational, electron and kinetic temperatures are in good agreement with one another, which indicates that the core region of atmospheric double arc argon-nitrogen plasma jet at the torch exit is close to the local thermodynamic equilibrium state under our experimental conditions.     

Numerical Simulation of Solitary Kinetic Alfvén Waves

Using the two-fluid model in the case of α〉〉1 （α= β/2Q, β is the ratio of thermal pressure to magnetic pressure, and Q = me/mi ）, we numerically investigate the interactions between two solitary kinetic Alfvén waves （SKAWs） and between an SKAW and a density discontinuity. The results show that the two SKAWs would remain in their original shapes and propagate at their initiating speeds, which indicates that SKAWs behave just like standard solitons. The simulation also shows that SKAWs will reflect and refract when crossing a discontinuity and propagating into a higher density region. The transmission wave is an SKAW with increasing density, and the reverberation is a disturbance with lower amplitude.     

Nonequilibrium dynamical phase transition of 3D kinetic Ising／Heisenberg spin system

We have studied the nonequilibrium dynamic phase transitions of both three-dimensional (3D) kinetic Ising and Heisenberg spin systems in the presence of a perturbative magnetic field by Monte Carlo simulation. The feature of the phase transition is characterized by studying the distribution of the dynamical order parameter. In the case of anisotropic Ising spin system (ISS), the dynamic transition is discontinuous and continuous under low and high temperatures respectively, which indicates the existence of a tri-critical point (TCP) on the phase boundary separating low-temperature order phase and high-temperature disorder phase. The TCP shifts towards the higher temperature region with the decrease of frequency, i.e. T_{TCP}=1.33×exp(-ω/30.7). In the case of the isotropic Heisenberg spin system (HSS), however, the situation on dynamic phase transition of HSS is quite different from that of ISS in that no stable dynamical phase transition was observed in kinetic HSS after a threshold time. The evolution of magnetization in the HSS driven by a symmetrical external field after a certain duration always tends asymptotically to a disorder state no matter what an initial state the system starts with. The threshold time τ depends upon the amplitude H_{0}, reduced temperature T/T_C and the frequency ω as τ=C·ω^α·H_0^{-β}·(T/T_C)^{-γ}.     

Wavelength-dependent nonlinear absorption of gold nanocages

The dipole resonances of gold nanocages were investigated theoretically using finite difference time domain method.The results show that field enhancement is obtained at the walls of the gold nanocages.It is believed that the effect can cause a strong optical nonlinear property.To test the hypothesis,nonlinear absorption was investigated using a broadband 5 ns Z scan.It was found that at low intensities the sample shows saturable absorption(SA),while at higher intensities a switch from SA to reverse SA occurs.Moreover,the nonlinear absorption of the sample is sensitively wavelength-dependent,and,in the resonant region,saturation intensity is the largest.     

Enhanced Field Emission from Well-Patterned Silicon Nanoporous Pillar Arrays

The silicon nanoporous pillar array （Si-NPA） is synthesized by using hydrothermal etching method, and the electron field emission properties are studied. The results show that Si-NPA has a low turn-on field of 1.48 V/μm at the emission current of 0.1 μA and its field emission is relatively stable. The field emission enhancement of Si-NPA is believed to originate from its unique morphology and structure. Our finding demonstrates that the Si-NPA is a promising candidate material for field emission applications.     

Energy of a Polaron in a Wurtzite Nitride Finite Parabolic Quantum Well

The effects of electron-phonon interaction on energy levels of a polaron in a wurtzite nitride finite parabolic quantum well （PQW） are studied by using a modified Lee-Low-Pines variational method. The ground state, first excited state, and transition energy of the polaron in the GaN/Al0.3Ga0.7N wurtzite PQW are calculated by taking account of the influence of confined LO（TO）-like phonon modes and the half-spaee LO（TO）-like phonon modes and considering the anisotropy of all kinds of phonon modes. The numerical results are given and discussed. The results show that the electron-phonon interaction strongly affects the energy levels of the polaron, and the contributions from phonons to the energy of a polaron in a wurtzite nitride PQW are greater than that in an A1GaAs PQW. This indicates that ehe electron-phonon interaction in a wurtzite nitride PQW is not negligible.     

Chaotic analysis of Atangana–Baleanu derivative fractional order Willis aneurysm system

A new Willis aneurysm system is proposed, which contains the Atangana–Baleanu(AB) fractional derivative.we obtain the numerical solution of the Atangana–Baleanu fractional Willis aneurysm system(ABWAS) with the AB fractional integral and the predictor–corrector scheme.Moreover, we research the chaotic properties of ABWAS with phase diagrams and Poincare sections.The different values of pulse pressure and system order are used to evaluate and compare their effects on ABWAS.The simulations verify that the changes of pulse pressure and system order are the significant reason for ABWAS'states varying from chaotic to steady.In addition, compared with Caputo fractional WAS(FWAS),ABWAS shows less state that is chaotic.Furthermore, the results of bifurcation diagrams of blood flow damping coefficient and reciprocal heart rate show that the blood flow velocity tends to stabilize with the increase of blood flow damping coefficient or reciprocal heart rate, which is consistent with embolization therapy and drug therapy for clinical treatment of cerebral aneurysms.Finally, in view of the fact that ABWAS in chaotic state increases the possibility of rupture of cerebral aneurysms, a reasonable controller is designed to control ABWAS based on the stability theory.Compared with the control results of FWAS by the same method, the results show that the blood flow velocity in the ABWAS system varies in a smaller range.Therefore, the control effect of ABWAS is better and more stable.The new Willis aneurysm system with Atangana–Baleanu fractional derivative provides new information for the further study on treatment and control of brain aneurysms.     

Dependence of electron dynamics on magnetic fields in semiconductor superlattices

Numerical simulation results are presented for a drift-diffusion rate equation model which describes electronic transport due to sequential tunneling between adjacent quantum wells in weakly coupled semiconductor superlattices （SLs）. The electron dynamics is dependent on the external magnetic field perpendicular to the electron motion direction, and a detailed explanation is given. Using different parameters, the system shows different dynamic behaviors, and three distinct phenomena are observed and controlled by increasing magnetic field. （i） For a lower doping density, the system state transfers from stable state to oscillationary state. （ii） An opposite result is obtained to that in the case （i） for an intermediate value of the doping density, and the state changes from oscillationary to stationary. （iii） The state varies between oscillationary and stationary when doping density is large. Then, a detailed theoretical analysis is given to explain these surprise phenomena. The distribution of the electric-field domain along the SLs is plotted. We find the structure of the domain is almost uniform for a lower doping density, and no domain occurs in the SLs. By adding an external ac signal, complex nonlinear behaviors are observed from the Poincaré map and the corresponding phase diagrams when the driving frequency changes.     

Zero-Magnetic-Field Spin Splitting of Polaron‘s Ground State Energy Induced by Rashba Spin-Orbit Interaction

We study theoretically the ground state energy of a polaron near the interface of a polar-polar semiconductor by considering the Rashba spin-orbit (SO) coupling with the Lee-Low-Pines intermediate coupling method. Our numerical results show that the Rashba SO interaction originating from the inversion asymmetry in the heterostructure splits the ground state energy of the polaron. The electron arealdensity and vector dependence of the ratio of the SO interaction to the total ground state energy or other energy composition are obvious. One can see that even without any external magnetic field, the ground state energy can be split by the Rashba SO interaction, and this split is not a single but a complex one. Since the presents of the phonons, whose energy gives negative contribution to the polaron‘s,the spin-splitting states of the polaron are more stable than electron‘s.     

An Anti-Control Scheme for Spiral under Lorenz Chaotic Signals

The Fitzhugh-Nagumo (FHN) equation is used to generate spiral and spatiotemporal chaos. The weak Lorenz chaotic signal is imposed on the system locally and globally. It is found that for the right chaotic driving signal,spiral and spatiotemporal chaos can be suppressed. The simulation results also show that this anti-control scheme is effective so that the system emerges into the stable states quickly after a short duration of chaotic driving (about 50 time units) and the continuous driving keeps the system in a homogeneous state.     

Growth of Structured Non—crystalline Boron—Oxygen—Nitrogen Films and Measurement of Their Electrical Properties

The boron-oxygen-nitrogen(BON) films have been grown on Si wafer by the low-frequency rf-plasma-enhanced metal-organic chemical vapour deposition method.The homogeneous film structure of completely amorphous BON is first fabricated on a low-temperature-made buffer at 500℃ with N2 plasma and is observed with a highresolution-electron microscope by the transmission-electron diffraction.The results show that the interfaces among substrate/buffer/film are clear and straight in the structured film.A heterogeneous film containing nano-sized crystalline particles is also grown by a routine growth procedure as a referential structure,The C-V characteristic is measured on both the amprphous and crystal-containing films by using the metal-oxidesemiconductor structure,The dielectric constants of the films are,therefore,deduced to be 5.9 and 10.5 for the amorphous and crystal-containing films,respectively,The C-V results also indicate that more trapped charges exist in the amorphous film.The binding energy of the B,O.and N atoms in the amprphous film is higher than that in the crystal-containing one,and the N-content in the latter is found to be higher than that in the former by x-ray photo-electron spectroscopy.The different electrical Property of the films is thought to originate from the energy state of the covalent electrons.     

Light intensity distribution of a new type of contact laser scalpel

The emergent light distribution of a new type of contact laser scalpel is measured in three different states using a light sensor.The relationship between the angle and the light intensity is analyzed.The results show that the strongest light is emitted from two sides and the front of the scalpel.The light from the front mainly plays a role of cutting.The light from two sides contributes to stanch the wound so as to remain a clear visual field during the surgery.It also helps to increase the cutting efficiency.     

Structural, elastic, phonon and electronic properties of a MnPd alloy

The structural, elastic, phonon and electronic properties of a MnPd alloy have been investigated using the first-principles calculation. The calculated lattice constants and electronic structure agree well with the experimental results. The microscopic mechanism of the diffusionless martensitic transition from the paramagnetic B2 (PM-B2) phase to the antiferromagnetic L10 (AFM-L10) phase through the intermediate paramagnetic L10 (PM-L10 ) phase has been explored theoretically. The obtained negative shear modulus C′= (C11-C12)/2 of the PM-B2 phase is closely related to the instability of the cubic B2 phase with respect to the tetragonal distortions. The calculated phonon dispersions for the PM-L10 and AFM-L10 phases indicate that they are dynamically stable. However, the AFM-L10 phase is energetically most favorable according to the calculated total energy order, so the PM-L10 →AFM-L10 transition is caused by the magnetism rather than the electron-phonon interaction. Additionally, the AFM-L10 state is stabilized through the formation of a pseudo gap located at the Fermi level. The calculated results show that the CuAu-I type structure in the collinear antiferromagnetic state is dynamically and mechanically stable, thus is the low temperature phase.