Atmospheric physics deals with very complicated natural phenomena. Basic models have to be implemented for the sea-air and land-air oscillators and then solve them using the approximate method. In this paper, a class of nonlinear coupling system for land-air oscillator model is studied. Using the homotopic mapping method, it is translated into solving linear problems, and the approximate expressi...
BEC(Bose Einstein Condensation)-BCS(Bardeen Schrieffer Cooper) crossover is currently one of the main research focuses in the area of cold atoms and BEC. In this paper, we study in detail the phenomenon of a phase slip in a superfluid Fermi gas near a Feshbach resonance, based on our previous work. The density profiles of a superfluid Fermi gas with a phase slip at various temperatures are compu...
Using the perturbed theory, the plasma channel produced by ultra-short ultra-high power laser pulses is considered. Under the actions of recombination, attachment and detachment, the perturbed asymptotic expressions of the density of each kind of charged particles in the course of evolution of the plasma channel are obtained. The influence of each action on the evolution and life_time of the chann...
The form invariance and the non-Noether conserved quantity of generalized Raitzin's canonical equations of non-conservative system are studied. The definition and criterion of the form invariance in the system under infinitesimal transformations are proposed. The necessary and sufficient condition under which the form invariance is a Lie symmetry is given. The Hojman theorem is established. Finall...
This paper studies the symmetries and non-Noether conserved quantities of mechanical systems with unilateral non-Chetaev nonholonomic constraints. The differential equations of motion of the systems are established, and the definitions and criterions of Lie symmetry and Mei symmetry are given. For the unilateral non-Chetaev nonholonomic constraint system, it is proved that under some conditions a ...
Extended mapping approach is introduced to solve the (2+1)-dimensional breaking soliton equations. On its basis, abundant propagating and non-propagating structures are found by selecting the arbitrary function appropriately. However, only periodic soliton wave structures are revealed in this paper.
The defect states in two-dimensional phononic crystal homogeneity dislocation structures has been studied by means of the plane-wave expansion method in combination with a supercell technique. Transverse dislocation structures and longitudinal dislocation structures are investigated respectively. The results show that, acting as a line defect, transverse dislocation structures can mold the flow of...
The s-wave bound states of the Klein-Gordon equation and Dirac equation with equal Manning-Rosen scalar and vector potentials are obtained, and the solutions are expressed by the hypergeometric function.
The s-wave bound states of the Klein-Gordon equation and Dirac equation with the Second Pschl-Teller scalar and vector potentials are obtained, and the solutions are expressed in terms of hypergeometric function.
Entanglement decoherence of two particles interacting with the same environment is investigated by means of concurrence and the input-output fidelity. It is found that the entangled states of two-particle system can be divided into two kinds, coherence-preserving states and fragile entangled states. The dynamics of entanglement decoherence for fragile entangled states is discussed by taking into a...
Utilizing the general linear quantum transformation theory, we give the exact expressions of evolutionary operator's matrix elements, wave function, expectation value of an observable and partition function, for multi-dimensional coupled and forced quantum oscillator.
Adopting Parikh's mode of quantum radiation as tunneling, the tunneling effect of Reissner_Nordstrm de Sitter black hole is studied. Under implementation of energy conservation, the result shows that the emission of the particle on the event horizon and the cosmic horizon is related with the change of Bekenstein_Hawking entropy and that the spectrum is not precisely thermal.
For a type of Fredholm integral equation with weak singularity integral kernel of logarithm function, the exact solutions is deduced through a calculus procedure when the free term is a triangle function. The singular character of solution is also analyzed when the variable is approaching the extreme points.
Based on the semiclassical quantum theory, we study the dynamical behaviors of Bose-Einstein condensate in an asymmetric Josephson junction. It is shown that the Josephson effect appears in the system when the ratio χ of the difference of two ground state energies to the interaction energies is zero. When χ≠0, the dynamical behavior of the system shows both the macroscopic quantum tunneling and th...
Based on Bose-Einstein condensation at minimized momentum state, a criterion for the validity of potential and the limited atom number loaded in a power law attractive potential well for ultra-cold atom gas is deduced. The criterion gives the required potential intensity when the loaded atom number is defined, or the limited atom number when the potential intensity is decided.
Starting from the support vector domain model, the paper establishes SVD predictive models of chaos time series as well as chaos phase trace of non-linear map, based on Takens phase space delay reconstructing theory. We adopted the methodof data set as support object elements. Machine self-learning reduces error upper limit of the generalized model. The three chaos time series, Henon/Lorenz/Rossle...
To recover the initial conditions of coupled map lattices (CML), which goes athwart the coupled systems, is one of key tasks of signal processing. Based on thecommon symbolic dynamic method, a novel time-varying symbolic dynamic method is proposed. The Logistic map is used to test the properties of the method. Numerical simulation shows that the new scheme can recover the statistical property of t...
According to the method of calculating maximal Lyapunov exponent (MLE) from univariate small data sets, an extended method based on multivariate time series is proposed. The extended method can search out optimal reconstructing parameters to meet the requirement of the original method for reconstructing multivariate phase space, and the method can compute the MLE by making use of the optimal recon...
It's of vital importance to estimate the unknown parameters of chaos systems in chaos control and synchronization. We firstly improve the newly developed particle swarm optimization (PSO) in view of the population initialization and objective function treatment. Then we use the improved algorithms for parameter estimation and on-line estimation of chaotic system for its global searching ability. ...
Making use of the well-known truncated-series method, we give a numerical program to calculate the exact solutions of two Coulomb-correlated ions confined in a linear Paul trap. The discrete motion state functions and energy spectra are obtained for the trap frequencies approaching the experimentally realizable limiting values, which correspond to a denumerable infinite point-set of the frequencie...
Generalized synchronization of two non-identical systems is studied based on Temam's inertia manifold theory of infinite dimensional dynamical systems. On the assumption that both systems have absorbing sets and attractors, the generalized synchronization manifold, which has the property of Lipschitz smoothness, invariance and exponential absorption, can be attained by defining a fixed point in a ...
The problem of controlling a class of new chaotic system is investigated. Applying Routh-Hurwitz criterion, we analyze the stability of the controlled system. The choice principle of feedback coefficients to attain control objective is proved strictly by combining the linear state feedback method. Numerical simulation results show that the method can effectively guide the chaotic trajectories to a...
This paper addresses the adaptive synchronization and parameter identification problem of two Chen systems with unknown system parameters. Based on the Lyapunov stability theory, an adaptive controller and the parameter update rule are designed. It is proved that the controller and update rule can make the states of the drive system and the response system with unknown parameters asymptotically sy...
Period-doubling bifurcation in a double-well Duffing-van der Pol system with bounded random parameters and subject to harmonic excitations is studied. The random system is reduced to its equivalent deterministic one by the Chebyshev polynomial approximation, through which the response of the random system can be obtained by deterministic numerical methods. Numerical simulations show that similar t...
A forced system with two time-delays, including van der Pol-Duffing types, is studied. The aim is to study the primary parametrical resonance bifurcation of this system. Perturbation method is used to obtain the bifurcation equation with time-delays. Based on the bifurcation equation, co-dimension one, co-dimension two and Hope bifurcation are discussed, and the effect of time-delays on the steady...
Turbo Codes can approach the Shannon limit very closely with the help of its special iterative decoding algorithm. This paper establishes a nonlinear dynamic system to analyze the relationship between Turbo decoding output and the number of iterations. Here, the number of iterations is taken as the time axis, decoding output as the state variable, SNR and information bits N as system parameters. I...
Under the condition of small deformation, a new nonlinear wave equation is derived to describe nonlinear wave evolution in a nonlinear elastic circular rod by means of Hamilton principle. The nonlinear constitutive relationship proposed by Cox and transverse Possion effects are simultaneously taken into account. Nonlinear wave equation and truncated nonlinear wave equation are solved by the Jacobi...
Based on the full velocity difference (FVD) model proposed by Jiang and Wu, we present an extended car_following model, called the multiple velocity difference (MVD) model. We attempt to enhance the stability of the traffic flow by using the velocity differences of multiple vehicles. It can be found that the critical value of the sensitivity in the MVD model decreases and the stable region is app...
A general scheme for the analog implementations of wavelet transform using switched_current (SI) filter circuits is presented. SI circuits are well suited for this application since the dilation constant across different scales of the transform can be precisely implemented and controlled by both the transconductance ratios (W/L) and the clock frequency. The circuits are composed of analog filter ...
In order to find the effects of high magnetic fields on the solidification processes of metallic materials, the changes of solidified structures of Al-14.98% Si and Al-9.2% Si alloys were examined in this study. The alloys were solidified under different magnetic field conditions, and then the distribution and morphologies of Si element in the solidified structures was analyzed. It is found that u...
The relaxation effects induced by excitation (or ionization) of inner subshell electrons and their influences on the electronic wave functions of the ground configuration 3p6 and five excited configurations 1s-14s, 2s-14s, 2p-14s, 3s-14s, and 3p-14s in Argon have been systematically studied by using the Multi_configuration Dirac_Fock method (MCDF). Furthermore, the transition energies and probabil...
The photoionization of acetone seeded in helium is studied by time_of_flight mass spectrometry using a 25 ns, 532 nm Nd: YAG laser with intensity in the range of 1010—1011 W/cm2. Multiply charged ions of Op+(p=2—4) and Cq+(q=2—4) of tens of eV have been observed when the laser beam irradiates the most dense part of the pulsed molecular beam. The intensity and the kinetic energy of the multiply ch...
A grating structure with the period of half of the laser wavelength is formed by focusing the atoms with a nearly resonant laser standing wave field. The motion of sodium atoms traversing an unsaturated potential are studied by the semi_classical approximation. The structures of gratings under various conditions were simulated using numerical method. By characterizing the grating with FWHM and con...
The electron emission induced by highly charged ions 207Pbq+(24≤q≤36) interacting with Si(110) surface is reported. The result shows that the electron emission yield Y has a strong dependence on the projectile charge state q, incidence angle ψ and impact energy E. In fitting the experimental data we found a nearly 1/tanψ dependence of Y. Theoretical analysis shows that these processes are closely ...
A two_dimensional array of resonant absorptive and dispersive medium is proposed. The transmission,reflection and absorption spectra of optical field transmitting in the structure are calculated. The photonic band gap caused by resonance(PBG), similar as the case of one_dimensional active photonic crystal, is observed. It’s found that the resonance between the border of the Brillouin zone and the ...
Based on the Mie theory,the light scattering properties in the visible regions of clouds consisting of pure water, pure ice spheres and concentric water_ice spheres are computed respectively. The reflection function and plane albedo, transmissivity, absorptivity of the three types of clouds are evaluated with the adding_doubling method by solving the radiative transfer equation. The numerical resu...
A diamond_like structure, which has a large complete photonic band gap and needs only a low refractive index contrast to open the complete photonic band gap, have been fabricated using four umbrellalike beams. By use of special prism to match the beams, diamond_like crystals with special surface orientations have been fabricated. The capability and feasibility of this method have been demonstrat...
A single_mode laser cubic model driven with quadratic pump noise is proposed. Closed laser intensity Langevin equation is got. Based on our early work of the Approximation Fokker_Planck equation (AFPE) for the systems driven by nonlinear external noise [Cao L and Wu D J 1988 Phys. Lett. A 133 476], the AFPE for laser intensity probability distribution is obtained. Exact analytic expression for the...
The spontaneous emission properties of a Λ_type atom embedded in anisotropic photonic crystals are investigated. We find that the dynamical properties of the atom and the propagating characteristics of the radiation field are obviously influenced by the relative position of the upper level from the forbidden gap and the space between the two lower levels. With the help of numerical calculation and...
From the quantum information point of view we investigate the entropy squeezing properties of a two_level atom with arbitrary initial state interacting with the coherent field via the two_photon process. The influence of the initial state of the system on the atomic information entropy squeezing is discussed. The numerical results obtained from the uncertainly relation of quantum information entro...
Based on the theory of coherent_mode decomposition of laser beams, the mode correlation and coherent_mode representation of the elegant Hermite_Gaussian (EHG) beams are discussed. The analytical expressions for the mode coherence coefficients (MCCs) of EHG beams, which include a coherent_mode representation that consists of finite coherent_modes, are derived. Furthermore, the difference of the M2_...
Supercontinuum generation in anomalous dispersion_flattened fibers through higher_order soliton compression effect is simulated and analyzed in detail. The results show that the second order differential constant of the dispersion parameter, dispersion parameter of the fiber and the pulse width, and peak power of the pump pulse are crucial to flat wideband supercontinuum generation, and the fiber...
The molecular structure of a series of coumarin derivatives were optimized and their second_order nonlinear optical polarizabilities(β) were calculated by the restricted Hartree_Fock (RHF) ab initio level with the 6_31G basis set in Gamess package. The results include both the distribution of charges in the ground and the excitated state and β under the external field(λ=1064nm). It is revealed th...
A broad complete photonic band_gap (larger than 18%) in compound square lattices, and both single and double absolute band gaps in compound triangular lattices are obtained by optimization of the structure parameter. The relationship curves between absolute band gaps and the structure parameter are demonstrated. The simulation results also show that the shifts of two sub_lattices affect the band_g...
Colloidal crystals are grown in capillaries. Experimental results demonstrate that these colloidal crystals are formed in a structure with cylindrical symmetry. The colloidal crystals are relatively stable. In all radial directions in the plan perpendicular to the axis of the capillary, the transmission spectra are the same and the wavelength of the band gaps are the longest. In other directions,...
Ultrabroadband spectrum is necessary for generation of ultrafast laser pulses; however, the extent of broadening the spectrum by its own nonlinear effect, such as self_phase modulation or cross phase modulation etc., is always limited. An easy way to broaden the spectrum to an octave is synthesizing the spectrum of its second-harmonic and the spectrum of itself. In this paper, influence of carrier...
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
A disscussion is given of the optical conductivity of decagonal quasicrystals. With group theory it is proved that decagonal quasicrystals may have different optical conductivity in the periodic and quasiperiodic directions. The formula is derived for the optical conductivity. The optical conductivity of Al65Co17Cu18 is calculated using this formula. The calculated results basically agree with th...
ZnO∶In thin films with thickness varying in the 210—240nm range were prepared on quartz substrates by sol_gel spin_coating technique. The structural properties of these thin films (In/Zn=0, 1, 2, 3 and 5at%) were studied by grazing incidence X_ray diffraction, conventional X_ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and photoluminescence. It is found that th...
Biopolymer_CdSe/ZnS core_shell quantum dot hybrid films were prepared using self_assembly technique. Compared with the absorbance spectrum, the photoluminescence excited by laser with λ=395nm has Stokes shift. The third_order nonlinear optical properties of biopolymer_CdSe/ZnS film were studied by Z_scan setup with femtosecond laser at 790nm. It is found that the nonlinear absorptive signal partia...
In order to improve the sensitivity of surface thermal lens(STL) absorption measurement, numerical simulations are performed based on STL diffraction theory. The optimization method for choosing proper instrument parameters, including the size and position of probe laser waist and the position of detecting fiber, is developed from the simulation. The sensitivity of the instrument reaches 0.1ppm a...
To investigate the significance of various many_body effects on the equation of state (EOS) of solid helium,the interaction energy of hcp crystal structure is expanded as a sum of two_ to five_body potentials in the present work. Each short_range many_body term between helium atom clusters is computed by means of Hartree_Fock (HF) self_consistent_field (SCF) method. It is indicated that at high de...
TiN/Al2O3 nanomultilayers with various Al2O3 layer thicknesses were prepared by multi_target magnetron sputtering. The chemical composition, microstructure and mechanical properties of these multilayers were characterized by energy dispersive X_ray spectrometry, X_ray diffraction, high_resolution transmission electron microscopy and nanoindentation. The result raveals that under the sputtering con...
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
In order to reveal the behaviors of Fe and RE atoms on grain boundaries in ZA27 alloy theoretically, the atomic structure model of high angle grain boundary of α phase in ZA27 alloy was set up by using the concept of coincidence-site lattice(CSL). The electronic structure (state density, Fermi energy level, structure energy) of grain boundary was calculated using the recursion method. The cluster...
The phase-field model based on Kim model which couples the solute field is used to simulate microstructural dendrite growth of multiple grains for Al-2-mole-Cu alloy. In order to improve the efficiency of calculation, an interpolative method is used to achieve the coupling of the macro field with the micro field. The influence of different undercooling on shapes of dendrites and distribution of so...
This paper studies the detailed beating oscillation in Shubnikov-de Hass (SdH) of magnetic two dimensional electron gas consisting of a modulation doped n type Hg0.82Cd0.16Mn0.02Te/Hg0.3Cd0.7Te first type quantum well, by which found that temperature, gate voltage are both bring the variety of magnetic resistance beating node position. By analyzing beating patterns, gate voltage dependent Rashba s...
Electronic energy and wave function of three-layer spherical nanometric system in homogeneous electric field is solved, the influence of applied field and sample size to the shift of Stark energy level is discussed.
To estimate the apex field enhancement factor associated with an array of carbon nanotubes (CNTs) on a planar cathode surface, the model of floating spheres between parallel anode and cathode plates is proposed. An approximate formula for the enhancement factor is derived, showing that the intertube distance of a CNT array critically affects the field emission. When the intertube distance is less ...
The charge stability has been systematically studied by measuring open-circuit thermally stimulated discharge (TSD) current spectra, in situ TSD charge spectra and isothermal charge decay for the polypropylene (PP) cellular films after chemical treatments ( extraction, oxidation and HF solution treatment). The results showed that a very strong new current peak, which the virginal film does not hav...
The Ni80.2Fe14.1Si0.2Mn0.4Mo5.1 sandwiched films are prepared on the magnetostrictive (Tb0.27Dy0.73)0.3Fe0.7 film substrate. Due to magnetostrictive stress effect on magnetic anisotropy which is believed to be critical for the giant magneto-impedance (GMI) effect, the GMI ratio is seen to increase sharply in the magnetic fields. The GMI effect also increases when the samples are annealed at 280℃. ...
The dissipative mesoscopic coupled circuits are obtained by the method of damped harmonic oscillator quantization . The quantum fluctuations of charge and current in an arbitrary eigenstate of the system have also been given .The result shows that the quantum fluctuations of the charge and current exist in all states, and the fluctuations in the component circuits are corelated.
The mechanism of negative bias temperature instability (NBTI) degradation in ultra deep submicron PMOSFET's is investigated. We mainly focus on the threshold voltage shift under subsequent positive bias temperature (PBT) stress after the preceding NBT. It's experimentally demonstrated that trapped holes from inversion channel and the diffusion of hydrogen molecules in the gate oxide are the major ...
The metal induced crystallization with chemical source on different silicon based films is studied. All amorphous silicon films deposited by LPCVD, RF-PECVD and VHF-PECVD have been crystallized. However, the a-Si films prepared by VHF-PECVD seems to have crystallized better. The crystallization was also affected by the concentration of the chemical solution. Under a certain conditions, the polycry...
We use a modified time-dependant Ginzburg-Landau model to study the characteristics of superconductive rings and evaluate the vortex motion equations. We show in theory that the flux has jumps, find sign reversal of the current and obtain expressions that are in accordance with the data of experiments.
In the framework of the Blonder-Tinkham-Klapwijk model,we calculate the differential tunneling conductance in normal metal / insulator / normal metal/triplet p-wave superconductor junctions which is studied theoretically as a function of the bias voltage. The results show that there are zero-bias conductance peak, zero-bias conductance dip, double-minimum structures and oscillation components of t...
We developed a 3D flux_line lattice model with magnetic interactions between intraplane and interplane vortices to simulate the transport properties and the dynamic behavior of disordered anisotropic superconductors. We observed a double peak in the differential resistivity as the driving current increases, which corresponds to a two-step depinning in the vortex motion. Between the two peaks we ...
By using high temperature optical microscopy (HTOM), the superheating phenomenon in YBa2Cu3Oz (Y123) oxide thin film was found by in-situ observation of its melting process. The origin of superheating is discussed in combination with the analysis of XRD pole figure and the unwettability of Ba-Cu-O melts. Besides, the relationship between the microstructure of YBCO thin film and its superheating de...
Double perovskite Sr2FeMoO6 with Al doping at Fe site up to 30% were prepared by traditional solid-state reaction. The degree of the cation ordering of Sr2FeMoO6 increases with Al doping obviously as shown by the refinement of room-temperature X-ray diffraction. The saturated magnetic moment per formula unit of these compounds decreases gradually with increasing Al concentration, but the magnetic ...
The resistivity and magnetoresistance of bulk polycrystalline La0.7Sr0.3MnO3-δ, fabricated to produce nanoscale grains sintered at different temperatures, have been investigated as functions of temperature. With decreasing temperature below room temperature the resistivity (ρ) exhibits a maximum near 250K, below which it shows “metallic" behaviour, i.e. ρ∝T2 in the temperature range from 50K to 17...
A new method of readout and writing process driven by perpendicular current in magnetoresistantive random access memory (MRAM) based on the magnetic tunneling junction is reported, and its schematic structure and operation are described.
The influences of W doping at Mn site on the magnetic structure of the charge-ordering system La0.3Ca0.7MnO3 are studied by the measurements of M_T curves,M_H curves and ESR spectra of polycrystalline samples of La0.3Ca0.7Mn1-xWxO3(x=0.00,0.04,0.08,0.12,0.15) are studied. The results show that when the doping amount is 0.00≤x≤0.08, the charge-ordering(CO) phase exists in the system, the AFM/CO sta...
A systematic study based on ab initio calculations within the local spin density approximation (LSDA) has been performed on the Ⅲ-Ⅴ semiconductors (GaAs and GaP) doped by the 3d-transition metals (TM=V, Cr, Mn, Fe, Co and Ni). It is shown that the ferromagnetic (FM) state will be realized when the GaAs and GaP are doped by V, Cr or Mn, however, the system is antiferromagnetic (AFM) when doped by F...
The effect of T substitution for Fe on the structure, spin reorientation and Mssbauer spectra of a series of Tb0.3Dy0.7(Fe0.9T0.1)1.95 (T=Mn,Fe,Co,B,Al,Ga) alloys at room temperature has been investigated systemically. The X-ray result shows that all samples are single phase having the cubic Laves-phase structure (C15). The analysis of the Mssbauer spectra indicates that the easy magnetization d...
Solving the Bloch equations is a core procedure in the optimal design of radio frequency pulses, which has direct impacts on the quality of acquired images in magnetic resonance imaging. Although the analytical solutions of the Bloch equations exist under some circumstances, they hardly can be applied for practical use because of their complexity and lack of generality. In this paper, we employ pr...
Arrays of Ni nanowires were electrodeposited into anodic alumina oxide templates with various pore diameters and porosity. The magnetization behavior of the Ni nanowire arrays was investigated with ferromagnetic resonance techniques and the vibrating sample magnetometer. Both ferromagnetic resonance spectra and hysteresis loops show that there is a strong dipolar interaction between the nanowires....
Using a method based on the system energy described by Smith and Beljers, the ferromagnetic resonance in ferromagnetic (FM)/Antiferromagnetic (AFM) bilayers under the stress field is studied. The thin FM film is taken to be a single crystal with cubic and uniaxial magnetocrystalline anisotropies, while the thickness of AFM layer is thin enough for its energy to be neglected. Numerical calculations...
The influence of charging parameters (such as charging voltage, charging time and charging temperature, etc.) on piezoelectricity and its thermal stability of cellular polypropylene film electrets was studied by means of contact charging and constant voltage corona charging methods and the thermal stimulated discharge technique. The cause of the influence is discussed in connection with the struct...
The necessary conditions of all-angle polarization beam splitting effect of photonic crystal is discussed from the aspects of band structure and equal frequency surface. The conservation law of the tangential k-vector component is illustrated in the equal frequency surface. In order to theoretically verify the all-angle polarization beam splitting effect, finite-difference time-domain (FDTD) metho...
Hexagonal InxGa1-xN film grown by metalorganic chemical vapor deposition (MOCVD) was studied by Micro-Raman scattering and X-ray diffraction. The phase separation was observed in InxGa1-xN, the biaxial stress was measured by both Raman and X-ray diffraction. In Raman spectroscopy, the A1(LO) mode of InxGa1-xN is absent. Instead, the LO phonon-plasmon coupled mode (LPP+) was observed at about 778 c...
In our experiment, the ZnO nanoparticles(diameter about 100nm) are optically pumped by the third harmonics (355 nm wavelength) of a pulsed Nd:YAG laser (30Hz repetition ration rate, 8ns pulse width). Laser-like light emission was observed in the ZnO nanoparticles. We simulate the ZnO particle density transport versus mean free path using the ring cavity theory. The result shows that random lasing ...
Ce3+ ions were introduced into the Er3+/Yb3+-codoped TeO2-WO3-ZnO glasses, and the effect of Ce3+ on the emission properties at 1.5μm band and the upconversion luminescence of Er3+ in the glasses was investigated. With the increasing of Ce3+ concentration, the emission intensity of Er3+ at 1.5μm band increases firstly, and then decreases. The optimal doping concentration of Ce3+ is about 2.07×1020...
The performance of polymer light-emitting diodes was optimized by dispersing titania nanotubes into different functional layers. When titania nanotubes are doped into the hole-transport layer, the hole mobility of the device is greatly increased due to the good p-type conductibility of titania nanotubes. In the case of doping titania nanotubes into emitting layer, irradivative recombination was de...
A quasi-one-dimensional coaxial photonic crystal has been assembled from a series of “tee”,“female” and “male” connectors. With the vector network analyzer the transmission coefficient and the phase information has been measured for different structures. The energy band structure has also been calculated with the method of transmission matrix under Bloch periodicity boundary condition. The experim...
INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
Carbon nanotips were prepared by plasma-enhanced hot filament chemical vapor deposition under different bias current using CH4, NH3 and H2 as the reaction gases, and investigated by scanning electron microscopy and micro-Raman spectrometer. The results indicate that the carbon nanotips have graphite structure. With increasing of the bias current, the tip angles of the carbon nanotips are reduced a...
Silicon thin films material with different crystalline ratio (Xc) have been deposited with varying silane content of source gases in the PECVD process. We have researched how hydrogen content affects the material and the relationship between micro-structure and optoelectronic properties. Light soaking experiment was then performed. By comparing the changes in the properties before and after irradi...
In the framework of a tight binding model, effect of the lattice site position fluctuation on the energy band and the electronic states of DNA is studied by means of stimulation with the square distribution. Effect of the position fluctuation on the conductivity of DNA is also analyzed. It is found that with the enhancement of the fluctuation the band gap becomes smaller and the electronic states ...
It is considered that complex systems far from equilibrium are evolved in avalanche and self similar multiplicative cascade way, and have characteristics of multifractality. By using the ground electric field data obtained in the middle of Qinghai-Xizang plateau region, multifractal behavior of lightning discharges in thunderstorm is investigated with wavelet-based multifractal method. It is found...
The conditional entropy of two symbolic sequences which are encoded faithfully from two different time series is minimized at the zero relative shift of the two time series if the two time series have their origins in the same underlying dynamics. This technique is also useful in studying the delayed coupling between different time series. Applications are made to the temperature data derived from...
Regarding Lorenz model as the forecast equation,this paper investigates the evolution of the number of particles falling into the predefined dynamic window and the average forecast weight X of the Lorenz system. Then we research preliminarily the predictability of the Lorenz system from another point of views, and the influence of the Gaussian white noises on the Lorenz system. The results show th...
Based on the extended Huygens-Fresnel principle, the spreading of partially coherent cosh-Gaussian beams propagating through turbulent atmosphere is studied by using the incoherent superposition of higher-order Hermite-Gaussian beams. The analytic expression of the mean-squared width of partially coherent cosh-Gaussian beams in turbulence is derived. It is shown that the spreading increases with i...
Based on laser atmosphere backscattering spectrum, the design and experiment of a Raman lidar system for measurement of atmospheric CO2 are presented. 354.7nm third harmonic of Nd∶YAG laser is transmitted with 350mJ pulse energy and repetition rate of 20Hz. The receiver employs a photomultiplier tube with quantum efficiency of 25% and 200MHz photon counter, and it detects Raman backscattering 371....
In this paper, we collect 119 γ-ray-loud Blazar (97 flat spectrum radio quasars (FSRQs) and 22 BL Lacertae objects (BL Lac)),and investigate respectively the correlation between the γ-ray emission (maximum, minimum, and average data) at 1GeV and the radio emission at 8.4GHz by discrete correlation function (DCF) method. Our main results are as follows: there is good correlation between the γ-ray i...
By using the brick-wall model, the quantum entropy of a cylindrical black hole in Anti-de Sitter space-time arising from the massless Dirac field is discussed. It is shown that the quantum entropy has both linear and logarithmical divergences if the usual contribution from the vacuum surrounding the system is ignored, and the whole expression does not take the form of the scalar one. Both the whol...