Implementation and analysis of the perfectly matched layer with auxiliary differential equation for the multiresolution time-domain method
Finite difference time domain analysis on electromagnetic scattering characteristic of plasma thin layer based on surface impedance boundary condition method
Sensitivity of delta-P1 approximation model to the reduced scattering parameter
Distributed-feedback laser based on low-scattering and high-gain holographic polymer dispersed liquid crystal grating
A nnovel wide field fluorescence sectioning microscope based on polarization filtering image enhancement and dynamic speckle illumination
Surface waves formed at the interface between a metal and a photorefractive crystal
Breather for weak beam induced by strong beam in strongly nonlocal nonlinear medium
A broadband artificial magnetic conductor composite structure for radar cross section reduction
Location-free optical microscopic imaging method with high-resolution based on microsphere superlenses
Characteristics of the fiber Bragg grating based all-fiber acousto-optic modulator
Generation of autofocusing beams with multi-Airy beams
Study on resonance frequency and equivalent circuit parameters of a thin disk in flexural vibration
The electro-mechanical equivalent circuit is the most common method of analyzing and designing composite transducers. However, for the thin disk, because of the complexity of flexural vibration, equivalent lumped parameters are difficult to obtain, and so this method is rarely used. From the point of equivalent view of the distributed parameter system and lumped parameter system, according to the kinetic energy equal principle and the potential energy equal principle in this paper, we give the lumped parameter equivalent mass and equivalent elasticity coefficient of the flexural vibration, and the resonance frequency equations as well. The results from the analytical method are in good agreement with those from the finite element method. Finally, the equivalent circuit of lumped parameter model of the thin disk in analyzing the composite vibration system is given. These results can serve as a reference for designing flexural vibration composite transducers.
Effects of Ge profile on thermal characteristics of SiGe heterojunction bipolar transistor with non-uniform doping profile in base region
Application research of symplectic Runge-Kutta method of solving Lagrange-Maxwell equation
Molecular dynamics simulation of isothermal crystallization dynamics in Cu nanocluster
Optimization of the longitudinal structure of intrinsic layer in microcrystalline silicon germanium solar cell
Twisting effects on energy band structures and transmission behaviors of graphene nanoribbons
A study of LED with surface photonic crystal structure fabricated by the nanoimprint lithography
Mechanism of three kink effects in irradiated partially-depleted SOINMOSFET's
Molecular dynamics investigation of shock front in nanocrystalline copper
The elasto-plastic deformation behavior, yield strength and strain rate of material under shock compression can be represented by shock front, and the shock front is also related to the variation of strength after shock compression. In this paper, we study the dynamic plastic deformation processe of nanocrystalline copper under shock compression through molecular dynamics simulations. We also explore the dependences of the shock front and the mechanism of elasto-plastic deformation on grain boundary, and make a comparison with the case of the shock response of nanocrystalline aluminum. This investigation shows that the contribution of grain boundary to the shock-front width of nanocrystalline copper are smaller than that of nanocrystalline aluminum. The plastic mechanism of nanocrystalline copper is dominated by the emission and propagation of partial dislocations, and the full dislocation and deformation twin are rarely found in the samples. From the simulations are also found that the shock-front width decreases with the increase of loaded shock stress. A quantitative inverse relationship between the shock wave front width and the shock intensity is obtained. This quantitative inverse relationship is close to other simulation result of nanocrystalline copper and quite different from results of coarse-grained copper compression experiments.
Density functional theory studies of O2 and CO adsorption on the graphene doped with Pd
Release melting of bismuth
Phase-change behaviors in Ga30Sb70/Sb80Te20 nanocomposite multilayer films
Microstructures and mechanical properties of (Ti, N)/Al nanocomposite films by magnetron sputtering
Roughening and pre-roughening processes on InGaAs surface
First-principles study on the effect of high Mn doped on the band gap and absorption spectrum of ZnO
According to the density functional theory, using first-principles plane-wave ultrasoft pseudopotential method, we set three different concentration Mn doped ZnO models, and perform the geomertry optimizations for the three modes. The total density of states, the band structures and the optical absorption are also calculated. The results show that in the case of non-spin state, the smaller the doping concentration of Mn is, the smaller the formation energy of ZnO is and the easier the Mn doping is, thus the stabler the crystal struetuer is; the Mn doping leads to the degenerations of the impurity energy band and the conduction band, and also to the optical absorption blue-shift. These calculation results accord with the experimental results. Moreover, the magnetism exists in the system under the situation of spin polarization, the absorption spectrum has a red-shift, which is consistent with the experimental result.
First-principles study on the energy bandgap bowing parameter of wurtzite BexZn1-xO
First-principles study on the electronic structures of Cr- and W-doped single-layer MoS2
We study the electronic properties of Cr- and W-doped single-layer MoS2 using an ab initio method according to the density functional theory. Our calculated results show the energy band structures of MoS2 are significantly affected by Cr doping, but not by W doping at a high doping concentration. The effects of Cr doping manifest as the transition of energy band structure from direct to indirect, and the decrease of band gap. Our further analysis reveals that strain is the direct reason for the change of electronic structure in the Cr-doped MoS2.
The DFT analyses of effect of chromium and nickel additions on the mechanical properties of Fe3Al based alloys
Optical properties of GaN:Tb nanoparticles synthesized by simple ammonification method
Photo-conductivity decay properties of Fe-doped congruent lithium niobate crystals
Phase transition of ultrathin Bi2Se3 film sandwiched between ferromagnetic insulators
For an ultra-thin Bi2Se3 film sandwiched between two ferromagnetic insulators (FIs), we investigate how its topological properties change with the angle between the magnetizations of the two FIs. The Chern numbers are calculated from the low-energy effective Hamiltonian for electrons in the surface states, and the bulk energy band and the edge states are simulated from the tight-binding model of a long ribbon with armchair edges on a two-dimensional honeycomb lattice, from which the topological phase of the system can be determined. It is found that with the magnetizations of the FIs varying from parallel to antiparallel, there appears a topological phase transition from the anomalous quantum Hall phase to the trivial insulating one at a critical angle.
Investigation of anti-reflection properties of crystalline silicon solar cell surface silicon nanowire arrays
New application of surface plasmon resonance-measurement of weak magnetic field
Comparison between exponential-doping reflection-mode GaAlAs and GaAs photocathodes
Local ferromagnetic structure in Heusler alloy Mn2CoGa and Mn2CoAl doped by Cr, Fe and Co
The crystal structures and magnetic properties of Mn2CoMxGa1-x and Mn2CoMxAl1-x (M=Cr, Fe, Co) alloys are investigated through experiment and calculation. Due to the covalent effect, the doped Fe and Co atoms preferentially occupy the A sites. It causes that some MnA (-2.1 μB) atoms become MnD (3.2 μB) and a local ferromagnetic structure of MnB-CoC-MnD is generated in the ferrimagnetic matrix, showing that an increment of molecular moment is as high as 6.18 μB. The achievement of the ferromagnetic structure consumes the exchange interaction energy, consequently, reducing the TC in Fe doping alloys. It is found that the toleration for doping Co in Mn2CoAl reaches up to x=0.64, much more than that in Mn2CoGa (x=0.36), and the change from ordered B2 to A2 structures along with the decrease of Al content. These observations reveal the importance of the covalent effect in these intermetallic compounds. The Cr doping shows an abnormal increment of molecular moment of 3.65 μB and increases the TC rapidly, which implies that Cr atoms may take an atomic configuration thereby disobeying to the occupation rule.
Morphology and ferromagnetism of Ge nanostructure
Quantitative analysis on the influences of the precursor and annealing temperature on Nd2O3 film composition
In this paper, ultra-thin Nd2O3 dielectric films are deposited on p-type silicon substrates by advanced atomic layer deposition method. Nd (thd)3 and O3 are used as the reaction precursors separately. The as-grown samples are annealed in N2 atmosphere in a temperature range of 700—900 ℃. The samples are investigated at room temperature by X-ray photoelectron spectroscopy and the changes of the film composition at different annealing temperatures are discussed in detail. For a higher precursor temperature of 185 ℃ in the deposition process, the ratio of oxygen to neodymium atoms for the as-grown film is 1.82, which is close to the stoichiometry. Dielectric constant increases from 6.85 to 10.32.
Method of accurately measuring silicon sphere density difference based on hydrostatic suspension principls
Study on the p-type conductivities and Raman scattering properties of N+ ion-implanted O-rich ZnO thin films
Effect of molecule polarity on the resonance raman spectrum of caroteniod
The resonance Raman spectra of nonpolar molecule all-trans-β-carotene and polar molecule canthaxanthin in nonpolar CS2 and polar 1,2-dicholoroethane in a temperature range from 243K to 293K are measured. The results show that polarities of the solute and solvent have a great effect on Raman spectrum. Raman scattering cross-section of nonpolar all-trans-β-carotene in nonpolar solvent CS2 is biggest and its bandwidth is narrowest. Raman scattering cross-section of polar canthaxanthin in polar solvent 1,2-dicholoroethane is smallest and its bandwidth is widest. The experimental phenomena are explained by solvent effects, coherent weakly damped electron-lattice vibration and effective conjugated length.
Vibrational spectra and first principles calculation of BaBPO5 crystal
In this paper, the lattice vibrational modes of the nonlinear optical crystal BaBPO5 are studied using polarized Raman spectrum and the first-principles calculation. The polarized Raman spectra are obtained in different configurations and recorded in a range of 100-1600 cm-1. Combining the experimental data of the FT-IR spectrum, the lattice vibrational modes of the internal and external vibrations are analyzed by the factor group analysis method. The results indicate that the primary Raman peaks of the BaBPO5 crystal are ascribed to the internal vibrations of the PO4 and BO4 tetrahedrons, and the vibrations of the PO4 tetrahedron show strong Raman- and IR-activity. On the other hand, the first-principles calculation indicates the correlation of the vibrational modes with the atomic activities. Especially, the Raman peak located at 672 cm-1 is ascribed to the vibration of the B-O-P bond, which is the connector between the PO4 and BO4 tetrahedron. These results obtained in this work are important for understanding the micro-structures of the BaBPO5 crystal, and the further study on the crystal growth mechanism.
Preparation and luminescent properties of Sr0.8-xBaxEu0.2WO4 red phosphors for white LED
Sr0.8-xBaxEu0.2WO4 red phosphors with different Ba2+ doping concentrations is prepared by the co-precipitation method at different sintering temperatures. We study the influences of the crystal orientation and lattice distortion of the samples on the luminescence property. The results show that the Sr0.8-xBaxEu0.2WO4 synthesized by the process has a phase with tetragonal structure and that the red emission 5D0-7F2 of Eu3+ in the sample can be excited effectively by the near-UV light and blue light. The part of Sr2+ replaced with Ba2+ leads to the increase in emission intensity of Sr0.8-xBaxEu0.2WO4. The doping concentration of Ba2+ has a great influence on the crystal parameter, the crystal symmetry and the luminescent property. The optimized doping concentration of Ba2+ is found to be 30%.
Preparation and near-infrared luminescence properties of Bi2O3-B2O3-BaO glasses
xBi2O3-50B2O3-(50-x)BaO glasses are prepared by melting method. Their infrared luminescence spectra, fluorescence decay curves and Raman scattering spectra are measured. No obvious near-infrared (NIR) luminescence is observed in 50Bi2O3-50B2O3 glass under 808 nm laser diode (LD) pumping. Adding BaO, broadband NIR luminescences are observed in 40Bi2O3-50B2O3-10BaO glass, 45Bi2O3-50B2O3-5BaO glass and 49Bi2O3-50B2O3-1BaO glass. With the increase of BaO concentration, no obvious NIR luminescences are observed in 30Bi2O3-50B2O3-20BaO glass, 20Bi2O3-50B2O3-30BaO glass and 10Bi2O3-50B2O3-40BaO glass. The NIR emissions with several emission peaks appear in 0.5Bi2O3-50B2O3-50BaO glass and 1Bi2O3-50B2O3-50BaO glass. The mechanism for the emission is investigated preliminarily.
Tunable properties of localized surface plasmon resonance wavelength of gold nanoshell
The effects of shell thickness, inner core size, and dielectric constants of core and embedding medium on the localized surface plasmon resonance wavelength of gold nanoshell are investigated by Mie theory. The results show that the extinction peak of gold nanoshell is first blue-shifted and then red-shifted with the increase of shell thickness, that the shift shell thickness corresponding to quadrupolar wavelength is greater than that corresponding to dipolar wavelength, and that the ratio of the shift shell thickness to the inner core size decreases with the increase of inner core size, and increases with the increase of dielectric constant of inner core or embedding medium. The resonance peaks in the scattering spectra have similar phenomena to those in extinction spectra as the shell thickness increases. The shift of the spectral peak is ascribed to the plasmon hybridization and phase retardation effect.
Extraction of effective constitutive parameters of active terahertz metamaterial with negative differential resistance carbon nanotubes
A strategy is presented to acquire active terahertz (THz) metamaterial by incorporating negative differential resistance carbon nanotubes. Furthermore, we propose a method of extracting active metamaterial effective parameters. This new method can effectively solve the problems of signs and multi-branches, while the traditional parameter extraction method becomes powerless for active case. Our results indicate that the active THz metamaterial with metal wires array not only has negative value of the imaginary part of the permittivity but also presents magnetic-dispersion characteristics.
One-step synthesis of a carbon nano sheet-scarbon nanotubes composite and its field emission properties
Design and reconfiguration of cognitive engine based on Bayesian network
Nonlinear dynamic model and chaotic characteristics of mechanical thastic energy storage unit in energy storage process
Effect of annealing atmosphere on characteristics of MONOS with LaTiON or HfLaON as charge storage layer
Modified symbolic relative entropy based electroencephalogram time irreversibility analysis
In this letter, we show that the trajectory of electroencephalogram (EEG) possesses the character of time reversal asymmetry, which can provide information about the entropy production of EEG. We develop a kind of new method to estimate symbolic relative entropy and entropy production using forward and backward trajectories. Finally, we use this method to dispose and analyse the EEGs of younger and elder people, and is turned out that this method works and the average energy dissipation can be used as a parameter to detect nonequilibrium.
The grand canonical Monte Carlo simulation of hydrogen physisorption on single-walled carbon nanotubes at the low and normal temperatures
Modelling and structure optimization of flat-panel thermal concentrated solar thermoelectric device
Influences of deposition rate in second stage on the Cu(In,Ga)Se2 thin film and device prepared by low-temperature process
Crosslayer parameter configuration for TCP throughput improvement in cognitive radio networks
Empirical analysis of microblog centrality and spread influence based on Bi-directional connection
The identifying of the most influential nodes in the complex network is of great significance for information dissemination and control. We collect actual data from Sina Weibo and establish two user relationship networks based on bi-directional “concern”. By analyzing the statistical characteristics of the network topology, we find that each of them has a small world and scale free characteristics. Moreover, we describe four network centrality indicators, including node degree, closeness, betweenness and k-Core. Through empirical analysis of four-centrality metric distribution, we find that the node degrees follow a segmented power-law distribution; betweenness difference is most significant; both networks possess significant hierarchy, but not all of the nodes with higher degree have the greater k-Core values; strong correlation exists between the centrality indicators of all nodes, but this correlation is weakened in the node with higher degree value. The two networks are used to simulate the information spreading process with the SIR information dissemination model based on infectious disease dynamics. The simulation results show that there are different effects on the scope and speed of information dissemination under different initial selected individuals. We find that the closeness and k-Core can be more accurate representations of the core of the network location than other indicators, which helps us to identify influential nodes in the information dissemination network.
Mechanism of dual-wavelength anti-jamming photoelectric smoke-detection
Carbon isotope ratio analysis in CO2 based on Fourier transform infrared spectroscopy
Partial Bessel electromagnetic wave
Entanglement properties in the system of atoms interacting with three coupled cavities which are in weak coherent states
We study the entanglement dynamics of the system comprising three two-level atoms resonantly interacting with three coupled cavities which are in weak coherent states initially. The atom-atom entanglement and cavity-cavity entanglement are investigated. The influences of coupling constant between cavities and intensity of the cavity field on entanglement properties are discussed. The results obtained using the numerical method show that atom-atom entanglement and cavity-cavity entanglement are both strengthened with the increase of intensity of the cavity field; on the other hand, atom-atom entanglement is weakened and the entanglement between cavity A and cavity B is strengthened with the increase of the coupling constant between cavities, and the entanglement between cavity B and cavity C has a nonlinear relation with the increase of the cavity-cavity coupling coefficient. These results are different from those in the case that cavity field is in vacuum state initially.
Entanglement dynamics in Majorana representation
With the help of the newly proposed definition of entanglement, the entanglement dynamics of a system composed of two bosonic atoms trapped in a symmetric double-well potential is investigated. For any state of this system, the description of Majorana representation can be analytically derived. It is found that the entanglement dynamics depends on both the atomic interaction and the initial state of the system. Specifically, the atomic interaction determines the oscillation frequency of the entanglement degree, whereas the initial state controls the oscillation amplitude.
Nonsingular terminal sliding-mode observer design for interior permanant magnet synchronous motor drive at very low-speed
Resonant behavior of a fractional linear oscillator with fluctuating frequency and periodically modulated noise
Feynman's ratchet and pawl heat engine in a one-dimensional lattice
In this paper, we studiy the Feynman's ratchet and pawl heat engine in a one-dimensional lattice. The dynamics of the particle is described by a master equation. The expressions of the current, efficiency and power output of the heat engine are derived analytically. The influences of the height of barrier, external load force and the temperature ratio of the heat reservoirs on the efficiency of heat engine are discussed. When the steady-state current is zero, there is a nonzero heat flux transterred from the hot bath to the cold bath, which is similar to the heat leak of the irreversible Carnot model. The curve of the power output versus the efficiency is a loop-shaped one. The heat engine is irreversible and the efficiency is less than the Carnot efficiency. The heat engine can work in optimal operation by optimizing the performance parameters of the heat engine.
Feedback compensation control on chaotic system with uncertainty based on radial basis function neural network
Parameter estimation for chaotic systems based on hybrid biogeography-based optimization
The signal-to-noise ratio of the quarter beam of wind imaging polarization interferometer
Primary spectrum pyrometry based on radiation measurement within a finite solid angle
Dielectric property of binary phase composite and its interface investigated by electric force microscope
The inverse method of carbon monoxide from satellite measurement and the result analysis
Thorium capture ratio determination through γ-ray off-line method
The differential cross sections and mechanisms of ionization and in the collisions of He2++H(1s) with strong magnetic fields
Neutral beam injection induced discrete Alfvén instabilities on experimental advanced superconducting tokamak
The neutral beam injection (NBI) system is applied to the experimental advanced superconducting tokamak (EAST). It will excite some Alfvén instabilities when the plasma characteristics are improved. The numerical research on the NBI-induced discrete Alfvén eigenmode (αTAE) and toroidal effect-induced Alfvén eigenmode (TAE) in the pedestal region is presented in the paper. The research results show that plenty of αTAEs appear in this region. The α TAE is very different from the TAE. These modes are trapped by the α-induced potential wells along the magnetic field line. Due to negligible continuum damping via wave energy tunneling, similar to TAE, the αTAE can also be readily destabilized by energetic particles. Differently, α TAE frequency spectrum is more broad than TAE, and they are existed not only inside the gap but also outside the gap. The growth rate increases with injected power increasing. This instability maybe affects the physical behavior of the tokamak and the confinement of the plasma.
Experimental research on X-ray radiation and ablation of an Ag foil targets irradiated by high intensity 2ω0 laser light beam
Influence of sea spray droplets on drag coefficient in high wind speed
Dynamic modification of the shallow water equation on the slowly changing underlying surface condition
The variation features of the surface mixed layer depth in Erhai Lake and Taihu Lake in spring and autumn and their mechanism analyses
Wind partitioning and reconstruction with variational method in a limited domain I: theoretical frame and simulation experiments
Global characteristics of the double tropopause derived from the COSMIC radio occultation data
Using the principle of critical slowing down to discuss the abrupt climate change