Design of high-gain broadband low-RCS waveguide slot antenna
A time-domain Gauss-Newton inversion algorithm for solving two-dimensional electromagnetic inverse scattering problems
Curved surface effect and characteristic emission of silicon nanostructures
Some bonds on the curved surface (CS) of silicon nanostructures can produce localized electron states in the band gap. Calculated results show that different curvature can form the characteristic electron states for some special bonding on nanosilicon surface, which are related to a series peaks in photoluminescience (PL), such as LN, LO1 and LO2 lines in PL spectra due to Si–N, Si=O and Si–O–Si bonds on the curved surface, respectively. In the same way, Si–Yb bond on the curved surface of Si nanostructures can manipulate the emission wavelength into the window of optical communication by the CS effect, which is marked as LYb line near 1550 nm in the electroluminescience (EL).
A 147 fs mode-locked erbium-doped fiber laser with a carbon nanotubes saturable absorber in evanescent field
Coherent emitting of multiple sub-beams for small target detection
Visible supercontinuum generation in dual-concentric-core-like photonic-crystal fiber
Improvement of the filtering performance of a heterostructure photonic crystal ring resonator using PSO algorithm
Investigation of a novel all-solid large-mode-area photonic quasi-crystal fiber
Study of prism surface plasmon resonance effect based on dielectric-aided layer
Study on the periodic error in ptychographic iterative engine imaging
Tunable three photonic band-gaps coherently induced in one-dimensional cold atomic lattices
Propagation of nonlinear waves in the bubbly liquids
Estimation of single hydrophone target motion parameter based on cepstrum analysis
Influences of sound absorption material on acoustic characteristics of acoustic vector sensor installed on a small underwater carrier
Robust source localization based on mode subspace reconstruction in uncertain shallow ocean environment
Defect state of the locally resonant phononic crystal
By taking a two-dimensional solid local resonant phononic crystal as an example, we investigated the mechanism of the defect state on a subwavelength scale. It is well known that, when the working wavelength is much greater than the distance between resonators, the dispersion of the phononic crystal is insensitive to the lattice structure, and the whole structure can be described in terms of the effective medium theory. As a result, it is hard to introduce a defect state in the system by a local real-space disorder. It is shown in this paper that the dispersion of the local resonant phononic crystal can be understood from the long-range feature of the interaction between resonators, so the creation of a defect state in the system is in fact to break such a long-range interaction. Based on this understanding, the mechanisms of the recently reported methods, that are used to create defect states, are discussed. In addition, a waveguide structure that can guide the longitude or transverse waves separately is realized by introducing an anisotropic defect resonator.
Characteristics of mapping domain of the acoustic field interference structures radiated by a moving target
Multiphysics-based simulation on heat conduction mechanism of TFC head and its influencing factors
Discrete element simulation of mechanical properties of wet granular pile
Shear test and physical mechanism analysis on size effect of granular media
Control of flow around hydrofoil using the Lorentz force
Non-equilibrium thermodynamic analysis of quasi-static granular flows
Granular flow is usually divided into three kinds of flow pattern, namely quasi static flow, slow flow, and rapid flow. The core issue of the research is the constitutive relation. A series of constitutive relations of application value have been received up to now, however, the study on principal theory is insufficient. Granular flow has an emergent mesoscopic structure, such as force chain network and vortex, involving complex irreversible processes. This paper studies its mesoscopic structure and principal characters, introduces the concept of two granular temperatures Tconf and Tkin of the granular flow to characterize the degree of chaotic motion and disordered configuration evolution, sets them as the non-equilibrium variables to constitute the thermodynamic state variables set for granular flow with the classical irreversible thermodynamic (CIT) variables, also determines the granular flow law of energy conversion and the entropy production rate, etc., and develops the two granular temperatures (TGT) model. Taking the simple shear quasi-static granular flow in a constant volume as example, and combining it with the discrete element method (DEM), this work confirms the material parameters needed for the TGT model, and analyzes the law of developing period and the effective coefficient of friction of steady period of granular flow.
Study on band gap properties of two-dimensional 8-fold quasi-periodic phononic crystals
Influence of H2 introduction on wide-spectrum Mg and Ga co-doped ZnO transparent conductive thin films
Electronic properties and modulation of structurally bent BN nanoribbon
Study on Grove model of the 4H-SiC homoepitaxial growth
In this paper, A Grove model on the homoepitaxial growth of 4H-SiC is presented, based on the structure and growth conditions of CVD system. According to the model analysis, the growth rate of 4H-SiC is quiet influenced by carrier gas flow rate and temperature, which is verified by experiments. Growth rate along the substrate has a bowl-shaped distribution, and the growth rate on the center is slightly lower than on the edge. As the carrier gas flow rate increases, the growth rate controlled by the transport changes into the reaction rate control, the growth rate first increases and then decreases. The position of highest temperature in the actor will be drifted with the carrier gas flow increasing. The reaction rate and the mass transport coefficient increase with the rise of growth temperature, which can cause the increase of growth rate. But the effect of temperature on reaction rate is much greater than on the mass transport. When the temperature rises excessively, the epitaxial growth will be determined by the mass transport. But the high reaction temperature results in forming some particles at the edge of reactor, which can reduce the growth rate, and the particles will have a chance to fall on the epitaxial layer, thus seriously affecting the quality of the epitaxial layer. All the above shows that the growth rate and thickness uniformity can effectively controlled by adjusting the flow rate of hydrogen, the rotational speed of the substrate and the growth temperature.
Investigation of the saturation characteristic and lifetime of the novel AlGaInP lightemitting diodes
Effect of thermal treatment on the structural phase transformation of the detonation-prepared TiO2 mixed crystal nanoparticles
Investigation of carrier transport properties along the c-axis in K0.8Fe2Se2 superconducting crystals
Electroluminescence from Si nanostructure-based silicon nitride light-emitting devices
Influence of Ce doping concentration on the luminescence properties of LaCl3：Ce scintillation crystals
LaCl3:Ce is an excellent rare earth halide scintillation crystal discovered in the beginning of this century. Pure LaCl3 crystal and LaCl3 crystal doped with several different Ce concentrations were grown by vertical Bridgman method. Their transmission and luminescence as well as decay time were measured and compared with each other. It was found that the cut-off edge, emission wavelength as well as decay time for pure LaCl3 crystals are respectively 215 nm, 405 nm and 1 μs. This emission is explained by the self trapped exciton (STE) of LaCl3. However, with the increase of Ce concentration in the crystal, the cut-off edge of LaCl3:Ce crystal shifts to about 300 nm, and the luminescence is dominated by the emission originating from 5d-4f transition of Ce ions. Meanwhile, the increase of the luminescence intensity of Ce3+ ion emission is accompanied with the expense of STE emission, this anti-correlation between the Ce3+ and STE luminescence intensity is interpreted by the energy transfer from STE to Ce ions in LaCl3:Ce scintillation crystals.
Effect of anisotropic surface tension on deep cellular crystal growth in directional solidification
Quasi-equilibrium growth of monolayer epitaxial graphene on SiC (0001)
Sublimation of SiC substrates is a promising way to prepare high-quality graphene on large scale. Nowadays, growth of high-quality epitaxial graphene is still a crucial issue. In this work, monolayer epitaxial graphene is grown on Si-terminated 4H-SiC (0001) substrate. By introducing argon inert gas and silicon vapor as background atmosphere, the Si evaporation rate and condensation rate on the SiC surface is close to equilibrium and the growth of monolayer epitaxial graphene with very low speed is realized. The growth duration of monolayer epitaxial graphene is prolonged to 75 minutes from 15 minutes. It is found that the disorder-induced Raman D peak shows an obvious decrease as the growth speed decreases, indicating the improvement of crystal quality, which makes the electrical properties of the monolayer epitaxial graphene is improved. The maximum carrier mobility and sheet resistance have reached 1200 cm2/V·s and 604 Ω/, respectively. The above results indicate that slowing down of growth speed by controlling of growth atmosphere is an efficient way to prepare high-quality epitaxial graphene.
Fractional-order multiple RLαCβ circuit
Numerical simulation of generation and radiation of super-radiation from relativistic backward wave oscillators
Optimization method for extracting ocean wave parameters from HFSWR
Effect of source/drain preparation on the performance of oxide thin-film transistors
The adhesion of two cylindrical colloids to a tubular membrane
Influences of driver’s attributions on signalized intersection traffic
A cellular automaton model is proposed to study the traffic at signalized intersection. The driving behaviors induced by driver’s attribution (gender, driving experience, character, etc.) are numerically analyzed. Simulation results show that the rusty driving skills or tension driving, impatient driving and so on can lead to the transition from free flow to congestion more easily, and these behaviors are the important cause for low travel efficiency at the intersection; the signal cycle is the main factor influencing traffic flux and travel time fairness.
Calculation of system risk in a dynamical bank network system
There have been many researches and rich results on the system risk in bank network systems that use complex network theory. Researches to date focus on the relationship between the contagion of the risk and the structure of the network after risk bursting, based on the assumptions that the accumulation of the system risk in network systems has approached the critical point of bursting and that the network is static (both the node and connection of the bank network are static).However, the problem why the system risk accumulates gradually and finally bursts in the network has not been addressed yet. The study on the system risk accumulation can only be conducted in dynamically evolving bank network systems; and the risk can be observed clearly only if the system risk is evaluated quantitatively. Therefore, a dynamically evolving complex bank network system, which has nodes of dynamic behavior and exhibits macroeconomic trends, is modelled first in the present paper. A lending-borrowing algorithm and a multi-term clearing algorithm for the dynamic bank network system are designed, and the method for calculating the system risk is proposed also. Finally, the system risk is calculated and analyzed by simulation. The curve of the system risk evolving with time is shown and the process of the accumulation of the system risk can be observed clearly. Researches in the present paper are to lay a foundation for the quantitative study of the system risk accumulation in dynamically evolving bank network systems.
Complexity analysis of traffic flow based on multi-scale entropy
New complex soliton-like solutions of combined KdV equation with variable coefficients and forced term
The [G’(ξ)]/[G(ξ)] expansion method is extensively studied to search for new infinite sequence of complex solutions to nonlinear evolution equations with variable coefficients. According to a function transformation, the solving of homogeneous linear ordinary differential equation with constant coefficients of second order can be changed into the solving of a one-unknown quadratic equation and the Riccati equation. Based on this, new infinite sequence complex solutions of homogeneous linear ordinary differential equation with constant coefficients of second order are obtained by the nonlinear superposition formula of the solutions to Riccati equation. By means of the new complex solutions, new infinite sequence complex soliton-like exact solutions to the combined KdV equation with variable coefficients and forced term are constructed with the help of symbolic computation system Mathematica.
Approximate analytic solution of solitary-like waves in a class of quantum plasma
A physical model for band gap of silicon-based photonic crystal of air hole at telecom wavelengths
Quantum discord in the system of atoms interacting with coupled cavities
Analysis of measurement device independent quantum key distribution with an asymmetric channel transmittance efficiency
Dynamically accessible variations for two-fluid plasma model
Cascading failure of scale-free networks based on a tunable load redistribution model
Solution of the fractional-order chaotic system based on Adomian decomposition algorithm and its complexity analysis
Research on train traffic flow affected by the line curve of the moving block system
Investigation of information bandwidth oriented spectrum sensing method
Variation of parameters and recovery in crystal lattice of 30CrMnSiNi2A
Aiming at the peaks overlapping in the field of X-ray diffraction, a new method for peaks separation was developed, and the parameters and recovery behaviors of crystal lattice of 30CrMnSiNi2A were investigated using RU-200V X-ray powder diffractmeter, by which the relationship between lattice parameters and carbon content at different tempering temperatures was obtained. Results show that the variation of lattice parameters of 30CrMnSiNi2A is consistent with high-carbon martensite on the whole, however there are some differences in the rate of change. The lattice parameter a is independent of carbon content, and slightly decreases with the rise of tempering temperature, while the amplitude of change for the lattice parameter c and carbon content is large, and a steep drop is observed in the process of quenching to the tempering temperature at 180 ℃, while the amplitude becomes flat aferwards for a higher tempering temperature.
Quenching rate of laser-excited lithium atoms with argon molecules in photochemical reaction
Study on cumulative fractional release of radionuclides in HTGR fuel particles
A novel scheme of beam smoothing using multi-central frequency and multi-color smoothing by spectral dispersion
Parametric excitation of axisymmetric toroidal electrostatic mode by drift wave turbulences
Numerical study on the effects of magnetic field on helicon plasma waves and energy absorption
Numerical study of the erosion of the EAST tungsten divertor targets caused by edge localized modes
Experimental investigations of tungsten X-pinches using the QiangGuang-1 facility
Nondestructive detection of nano grating by generalized ellipsometer
The silicon nanometer structure grating and the photoresist nanometer structure grating were prepared. A fitting model was built on the new self-developed generalized ellipsometer. Then, the gratings was tested and fitted. Results proved that the machine could work well in nondestructive test of nano grating. Under the condition of the incident angle of 60° and the azimuth angle of 75°, the measurement accuracy can be up to 99.97% for the three-dimensional morphology parameters such as key dimension and sidewall angle and so on, and the maximum error is less than 1%. This method is significant for the nondestructive test.