A new method to predict the wind direction from HF radar Doppler spectrum
According to the relationship between the first-order Doppler of HF radar and the wind direction over the sea surface, a new method of predicting wind direction is proposed with considering the combination of neural network and the method of the beam sampling. Using the simulated data under different input and output parameters of neural network, the wind direction is predicted when the expansion factor is odd number, the combination of the neural network and the beam sampling is utilized to predict the wind direction when the expansion factor is even number, which can eliminate the fuzziness of the wind direction. The predicted result shows a good agreement with the simulated data. From the predicted results by the neural network and the beam sampling, it is find that the error of the wind direction is about 4°-6° and the mean error of the expansion factor of the wind direction is 0.26, which provides a new idea and method of predicting the wind field over the sea surface.
Electromagnetically induced negative refraction induced by microwave field driving hyperfine levels transition
High efficient anti-Stokes signal conversion in photonic crystal fiber
Time-resolved spectrum characteristics of instantaneous plasma generation and evolution processes in nanosecond laser-Cu-target
Numerical simulation and experimental study of thermal-induced-depolarization in 2 μm Cr,Tm,Ho:YAG laser
The theory of thermal-induced-depolarization is analyzed, the distribution of depolarization is numerically simulated, and the result is verified by the polarized light interferometry. The experimental result is coincident with the numerical simulation, which shows that the distribution of depolarization in the cross section of Cr,Tm,Ho:YAG is crisscross, and increases with the pump energy increasing. The direction of the worst depolarization is 45° with respect to the polarization direction of the polarizer. According to the numerical simulation, we employ a λ/4-plate to compensate the depolarization of a high-energy Cr,Tm,Ho:YAG laser. The pulse energy increases by 24% after compensation.
A high power photonic crystal fiber laser oscillator based on nonlinear polarization rotation mode-locking
Multi-beam laser heterodyne measurement with ultra-precision for the glass thickness based on oscillating mirror sinusoidal modulation
Focal depth of digital lensless Fourier transform micro-holographic system
Binary collision approximation for solitary wave in periodic dimer granular chains
We study solitary wave propagation in periodic dimer granular chains of beads with the same material but different sizes by binary collision approximation. This kind of chain which is called “N:1 dimer” consists of pairs of N big beads and one small bead. First we present a method to map the actual chain into an effective chain, then use the binary collision approximation to obtain the transmitted solitary wave speed, the total time taken by the pulse to pass through the chain, and the frequency of oscillation of the small particle. Frequency of oscillation, which increases with the decrease of the radius of the small particle, is analytically obtained. And the results are in excellent agreement with numerical results. For the total time of the pulse passing through the chain, the results of theoretical analysis is in good agreement with numerical results when N ≤ 2. The relative error seems no change with the chain length but becomes larger with the increase of the value of N.
Dynamic simulation of fiber orientation in mold filling process in a complex cavity
Electronic theory of the mechanism of corrosion of Pb-Mg-Al alloy
Defining nearest neighbor clusters in alloy phases using radial distribution of atomic density
Investigation of proton irradiation damage in BaTiO3 thin film by computer simulation
Stability of hydrogen in tungsten with carbon impurity: a first-principles study
Amending the ferromagnetic properties of Ga0.94Mn0.06As films by He+ irradiation
First-principles investigations on the electronic, elastic and thermodynamic properties of Cr2MC(M=Al, Ga)
We investigate the electronic, elastic and thermodynamic properties of nanolaminate Cr2MC(M=Al, Ga) by using the ab initio pseudopotential total energy method. Our results show that they have shown almost identical volume compressibilities. The axial compressibility investigations show that the c axis is always stiffer than a axis. The internal coordinate calculations revealed that the values of Cr atoms in Cr2AlC are always larger than those in Cr2GaC. The elastic constants calculations demonstrated the structural stability within 0–50 GPa. The obtained bulk moduli by quasi-harmonic Debye model observed that the bulk moduli of Cr2MC(M=Al, Ga)decrease with temperature at 0 GPa, but increase at 300 GPa. We also found that the Debye temperatures of Cr2GaC are always smaller than those of Cr2AlC at any conditions. However, the opposite cases can be found in thermal expansion coefficients, Grüneisen parameter, entropy and heat capacity when comparing their respective counterparts between Cr2GaC and Cr2AlC. The electronic density of states and energy band distribution demonstrated that the Cr2MC(M=Al, Ga) have shown similar profiles with the only exception of the more localized s and p electrons in Cr2GaC than their respective counterparts in Cr2AlC.
Experimental study of thermal conductivity of polyethylene nanowire arrays fabricated by the nanoporous template wetting technique
We fabricate low-density polyethylene (LDPE) nanowire array with a diameter of 200 nm by using a nanoporous template wetting technique, and the thermal conductivity at 20–80℃ is experimentally studied by a nanosecond laser flash method. The measured thermal conductivity of the fabricated nanowire array is about 2.2 W/mK at room temperature, which is about one order of magnitude higher than its bulk counterpart. The thermal conductivity is found to increase slightly with the increase of temperature. The estimated thermal conductivity of a single LDPE nanowire is as high as 5 W/mK at room temperature. The high orientation of chain of the LDPE nanowire may arise from the integrative effects of shear rate, vibrational perturbation, translocation, nanoconfinement and crystallization. Findings in this study provide a useful strategy for enhancing the intrinsic thermal properties of polymer nanostructures.
Variation of adhesive force in the nanoscale contact
Study of growth of -oriented CdTe thin films by MBE
Oxygen adsorption on Nb(110) surface by first-principles calculation
First-prinicples study of Li-N and Li-2N codoped p-type ZnO
First-principles study of structural stability and electronic properties of rhombohedral and tetragonal PbZr0.5Ti0.5O3
Optical properties of N-doped Cu2O films and relevant analysis with first-principles calculations
First principles investigation of interaction between interstitials H atom and Nb metal
Research of electronic and magnetic properties on gold doped zigzag graphene nanoribbons
Synthesis and thermoelectric properties of nanostructured bismuth telluride alloys
One-shadow-mask ultralow-voltage indium-tin-oxide thin-film transistors on paper substrates
Stress models relevant to Raman spectrum in uniaxial/biaxial strained Si
A semiempirical model for kink effect on the AlGaN/GaN high electron mobility transistor
A new phenomenon of photoconductive InSb detector under the irradiation of out-band laser
A analytic model for the threshold-voltage of novel high-speed semiconductor device IMOS
Photoinduced change in resistance of charge-ordering Gd0.55Sr0.45MnO3 thin film
The compound and the film of the critical charge-ordering Gd0.55Sr0.45MnO3 thin film are prepared using the solid state reaction technique and the pulsed laser deposition method respectively. The properties of the photoinduced relative change in the resistance of the film are investigated. Experimental results indicate that the film exhibits the semiconductive conduction and the charge-ordering temperature is about 70 K from the fitting of a variable-range hopping model. The maximum value of the photoinduced relative change in resistance is about 99.8% when the laser with a power density of 40 mW/mm2 irradiates the film, and the rise time is about 8s independent of temperature. The maximum value of the photoinduced relative change in resistance is about 44% at T=20 K when the laser with a power density of 6 mW/mm2 irradiates the film. The time constant is increased with the increase of temperature, which is attributed to the competition between photoinduced effect and thermal fluctuation.
Experimental study of magnetic quantum-dot cellular automata function arrays
Effect of surface plasmon polariton of Ag nanoparticles on the photoluminescence property of up-conversion materials
Study on the local field enhancement of elliptical gold nanotube
Theory research of negative dynamic conductivity in electrically pumped multiple graphene layer structures with split gates
Molecular dynamics simulation of energy exchanges between single hydrogen and graphite(001)
The effect of substrate on terahertz transmission properties through metal subwavelength dual-ring structure
Study on 3D von Neumann equation with anisotropy for convex grains
Mesoscopic picture of fracture in porous brittle material under shock wave compression
Effects of mechanical alloying process on thermoelectric properties of Bi2S3 Bulk
Determination of optical constants and thickness of photoactive layer in polymer oslar cells by single transmission measurement
Parameter-induced stochastic resonance in overdamped system with α stable noise
Parameter-induced stochastic resonance is an important method of detecting weak signal from noise, but under α stable noise background, this method has not been reported. In this paper, we study the parameter-induced stochastic resonance in an overdamped system with α stable noise. Our investigation discloses that the stochastic resonance can be realized by tuning the system parameter under α stable noise background; when the nonlinear term parameter is turned, the resonant effect becomes weakened as the α stability index α decreases. But when the linear term parameter is turned, the resonant effect becomes strengthened as the α stability index α decreases. Our observation is significant for understanding the positive role of α stable noise in weak signal detection, which is helpful for understanding the effects of different α stable noises on stochastic resonance systems.
An efficient adaptive method of improving the synchronization of complex networks
A study of basin of attraction of the simplest walking model based on heterogeneous computation
Passive dynamic walking becomes an important development for walking robots due to its simple structure and high energy efficiency, but it often falls. The key to this problem is to ascertain its stable gaits and basins of attraction. In order to handle the discontinuity, massive numerical computation is unavoidable. In this paper, we first propose an algorithm to compute Poincaré maps in heterogeneous platforms with CPU and GPU, which can take the best performance of the newest heterogeneous platforms and improve the computing speed by more than a hundred times. With this algorithm, we study the simplest walking model by sampling massive points from the state space. We obtain high resolution images of the basin of attraction, and reveal its fractal structure. By computing the relation between the stable gaits and their basins and by varying the slop k, we find a new three-period stable gait and a period-doubling route to chaos, and we also study the new gait and its basin.
A new hyperchaotic system and its adaptive tracking control
SPIHT-based joint image compression and encryption
Prediction of multivariable chaotic time series using optimized extreme learning machine
Frozen random patterns in a globally coupled discontinuous map lattices system
Reseach on accommodation parameter of linear bridging relation for blunt cone in transitional regime
Three-dimensional optical modeling of color filter liquid-crystal-on-silicon microdisplays
Finite element analysis of the high-pressure tungsten carbide radius-anvil
The high-pressure tungsten carbide (WC) radius-anvil is analyzed and studied based on the finite element method (FEM). The results indicat that under the same transfer efficiency of pressure, the lifetime of high-pressure WC radius-anvil is longer than that of the traditional anvil, which can be enhanced about 3.05%–16.75%. The highest sample cell pressure generation by the new design of high-pressure WC radius-anvil increases about 5% (from 5.80 GPa to 6.09 GPa) compared with that by the traditional anvil, which can be attributed to the technology of radius-bevel. The high-pressure WC radius-anvil will be indeed very useful to broaden the synthetic region of functional materials. Further more, in this work, the operational costs of cubic high-pressure apparatus is reduced and the cubic anvil type high pressure techniques is improved in many important aspects.
GaP terahertz emitter with micro-pyramid anti-reflection layer
Joint production of Z boson and charged top-pion pair at the ILC
Self-focus and transmission of relativistic electron beam in a dynamically loaded plasma
In order to further study the radiation of the relativistic electron beam-ion channel experimentally and theoretically, the propagation of a relativistic electron beam in neutral gas and its self-focusing process are investigated. Particle in cell (PIC) simulation shows that the electron beam can self-focus and transmit the dynamically loaded plasma through impact ionization. The transverse and the longitude inhomogeneities of the ion background have significant effects on the transport properties of the electron beam. Base on these researches, a model of transmission of electron beam in a transverse non-uniform ion background is supposed. And the condition of self-focus is given. The numerical results show that the transverse inhomogeneity will lead to the mixed phase transmission of the electron beam, and the inner electrons can defocus near the focus point, which is consistent with the PIC simulation. The PIC simulation also shows that due to the self-focusing of the electron beam, there are much more ions to be ionized at the focus point, which will capture the lower-energy electrons after collision, the capture electron effect will significantly reduce the efficiency of the transmission of the electron beam. But the distribution of the captured electrons in the longitude direction is quasi-periodic, which acts as the electrostatic Wiggler field. These may achieve the dynamical loading of the electrostatic Wiggler field. These results give new clues to the further study of electron beam-plasma system in experiment and the establishment of theoretical models.
Population transfer of high excited states of Rydberg sodium atoms in a chirped microwave field
Geometric structure and electronic characteristics of NaBn (n=1–9) clusters
The geometric configurations, electronic structures, vibrational frequencies, and average binding energies of NaBn(n=1–9) clusters are studied using the B3LYP DFT method at 6-311+G(d) level. The stabilities of the ground states of NaBn(n=1–9) clusters are analysized by means of energy gaps, and secondary energy differences between the ground state structures. And the polarizations are studied.
First principles study on the structure and mechanical properties of hcp-C3 carbon bulk ring
Electroluminescence properties of SiN molecule under different external electric fields
Structures and potential energy functions of the ground states of YH,YD,YT molecules
Using the density functional theory(B3LYP) method, the 6-311++G(3df,2pd), AUG-cc-PVTZ, AUG-cc-PVQZ basis sets for H and effective core potentials for Y, the energies, equilibrium structure and harmonic frequency of the ground states of YH(D,T) molecules are calculated. Based on the theory of atomic and molecular reaction statics, the reasonable dissociation limits of the ground states of YH(D,T) molecules are derived. By comparing the calculation results with the existing experimental and theoretical values, we find that the mixed basis sets LANL2TZ/AUG-cc-PVQZ are most suited for the calculation of the molecules. Consequently, the potential energy surfaces of the ground states of YH(D,T) molecules are scanned at the B3LYP/LANL2TZ/AUG-cc-PVQZ level of theory. The potential energy curves of the ground states of YH(D,T) molecules are obtained by the least square fitting to the Murrell-Sorbie potential energy function. The spectroscopic constants (Be, αe, ωe, ωeχe, De) and force constants ((f2, f3, f4)are calculated and compared with experimental results, indicating that the calculation results are in good agreement with the experimental data.
Atomic process in high-temperature radiation field
Experimentally studying the scheme on exciting coherent population trapping resonances with lin//lin configuration
Influence of left-handed materials on the spontaneous emission spectrum of V-type three-level atom
Electron broadening of the resonance lines of Ar+17 and Ar+16
With the revised UCL wave code, the reactance matrix can be calculated when an electron impacts on an ion, so that the scattering matrix and the collision strength are calculated. With the collision strength, the electron broadening of the resonance line is studied. Specifically, the widths and the shifts of resonance lines emitted from Ar+17 and Ar+16 are calculated under the different values of electron temperature and electron density.
Evolution of ultracold 70S Cs Rydberg atom
High-gain Raman scattering spectrum of trapped atomic gas
Theoretical study of the P-branch spectral lines in d1Σ+–b1Σ+ electronic state transition of NbN molecule
The accurate P-branch spectral lines of high-lying rotational quantum states of (1,1) band in d1Σ+–b1Σ+ electronic state transition of NbN molecule are obtained in this work using the analytical formula proposed in Sun's previous work. The formula not only reproduces all known experimental spectral lines excellently, but also generates the correct values of the unknown spectral lines up to J=80 that are unavailable experimentally for this band.
Spectrum of PuO under inner radiation fields
A density functional method DFT/B3LYP with SDD basis for Pu and 6-311+G* basis for O is used to study HOMO energy level, LUMO energy level, energy gap, and harmonic frequency of PuO ground state molecule under different inner radiation fields ranging from -0.005 to 0.005 a.u.. The results show that the magnitude and the direction of the electric field have important effects on these characteristics of PuO molecule. The HOMO energy level is found to decrease, but the LUMO energy level, energy gap and Fermi energy level are found to increase with the increase of electric field. The electron which occupies orbital is difficult to stimulate to empty orbital and transform into excited state. The PuO molecule is more stable in inner radiation field, and it can prevent O2, H2 and so on from proliferating to superficial inner layer and corroding the plutonium surface, which contributes to the plutonium corrosion prevention in inner radiation field.
Generating isolated attosecond pulses at an arbitrary angle of the two-color polarized laser pulse
The theoretical calculation of (e,2e) triple differential cross sections of Ag+ (4p,4d) in coplanar asymmetric geometry
The three-body distorted-wave Born approximation is used to calculate the (e,2e) triple differential cross sections (TDCSs) of Ag+(4p10) and Ag+(4d10) in different kinematical variables in coplanar asymmetric geometry. The angles 4°, 10° and 20° are selected as the scattering electron angles. We find that the position of binary peak or the dip between split peaks are not in the direction of momentum transfer, which is probably ascribed to one kind of double-binary collision. We also find that the binary peaks show abnormal splits for Ag+(4p10). Such abnormal splits indicate that an (e,2e) process for inner valence orbital of ionic target becomes more complicated than for outer valence orbital. Furthermore, beside the binary peak and the recoil peak, some pronounced peaks appear at certain ejected angles in the (e,2e) TDCSs of Ag+(4p10) and Ag+(4d10). We consider that these pronounced peaks are probably related to one kind of double-binary collision.
Momentum transfer dependence of the triple differential cross section for electron impact ionization of helium at incident energy of 150 eV
Theoretical study of shield effect in the momentum transfer dependence of the cross section
Cross sections for the electron impact non-dissociative ion of hydrogen and its isotopic molecule
Calculation study of the geometry structures and electronic properties of heterofullerenes C19M(M=Cr,Mo,W)
The possible geometrical structures of C19M(M=Cr,Mo,W) molecules are optimized by using the density functional theory (B3LYP) at the LANL2DZ level. For the ground state structures of C19M(M=Cr, Mo, W) clusters, the physical and the chemical properties are studied. The results show that the kinetic stabilities of the C19M clusters with different M atoms are almost the same. Theis thermodynamic stabilities are obviously increased with the increase of atomic number. It can be found from the frontier orbital that the M atoms have the effects on the orbits more or less. M atom contribution to the orbits roughly increases with M atomic number increasing. A great many of positive charges accumulate on the M atoms in C19M clusters. Their aromaticity decreases with the increase of atomic number.
Magnetic control of the constant-current glow discharge plasma characteristics
Theory and simulation of laser pulse trapping and amplifying in the interaction with a thin foil and a solid target
Pressure increase in foam-solid target from X-ray driven shock waves
A three-dimensional particle-in-cell/Monte Carlo computer simulation based on negative hydrogen ion source
One-dimensional simulation of dielectric barrier glow discharge in atmospheric pressure Ar
Genetic algorithm with regularization method to retrieve ocean atmosphere duct