Collimated electrons generated by intense laser pulse interaction with cone-structured targets using particle simulation
Statistical characteristics and variation of speckle intensity in deep fresnel diffraction region
Influence of filling factor on far-field intensity distribution in coherent beam combination
Generation of cylindrical vector beams based on metasurface
Study on the cascade classifier in target detection under complex background
Spontaneous emission from a two-level atom in a dynamic photonic crystal with an isotropic disoersion relation
Multistable phenomenon of the Y-type four-level atom-assisted optomechanical system
A cross bus single microring electro-optical switch with U bend waveguide
Effect of Raman gain on the characteristic of soliton transmission in birefringence optical fiber
Generation of broadband multicolor femtosecond laser pulses by using cascading four-wave mixing in a CaF2 plate
Atmospheric temperature profiles estimated by the vertical wind speed observed by MST radar
Experimental investigation of dredging thermal protection system of hypersonic vehicle leading edge
Experimental features and mathematical model of pedestrian evacuation from a room with two exits
A cellular automaton model for the road in front of elementary and middle school gates during students going to school
An analytical solution for the interaction of two-dimensional currents and gravity short-crest waves
The flow and heat transfer characteristics of double droplets impacting on flat liquid film
Study on the excited states of zinc porphyrinogen and anisotropy of 2, 2, 6, 6-tetramethylpiperidinooxy by the technology of electron paramagnetic resonance
Surface plasmon enhancement effect in molecular excitation
Enhancement effect of surface plasmon in the metal nano-particle is a hot topic in nano-material field. A system is investigated where a spherical metal nano-particle is placed near a dye molecule. Under the optical excitation of a polarized electric field the subsequent charge transfer dynamics for different relative positions are simulated by density matrix theory approach, where the Coulomb interaction of molecule and metal nano-particle is calculated in the framework of the dipole-dipole approximation. It is found that the enhancement effect is closely related to the relative distance between the molecule and metal nano-particle. Effect of enhancement due to the surface plasmon is discussed in detail for various coupling interactions, polarization of field, lifetime of plasmon, and non-resonant excitation; and the physical essence in the molecule-metal nano-particle coupled system is analysed.
Luminescence characteristics of PVK doped with red-emitting quantum dots
Multilayer electroluminescent devices with a system in which red-emitting quantum dots doped PVK serves as the active layer is fabricated through non-treatment process, the device structure being ITO/PVK:QDs/Alq3/Al. Measuring the emission spectra and electrical characteristics of the devices we study the effect of different QDs doping concentration (mass fraction), and propose some possible solutions to optimize the PVK:QDs system after taking pure QDs for comparison. Experimental results show that changing QDs doping concentration would bring significant impact on the electroluminescence (EL) spectra, current density, brightness, and the stability of devices. When QDs doping concentration is low, we will mainly see the light of Alq3; when QDs doping concentration is 20%, saturated pure red light emission is observed and it is brighter than other devices. However, when the doping concentration is high, a slight red shift occurs in the EL spectra, and the performance of the device gets worse. With a suitable doping concentration, the PVK:QDs may increase the stability of devices.
First-principles study on phonon properties of iron-based fluoride superconductors SrFe1-xCoxAsF (x=0, 0.125)
Thermophysical properties and rapid solidification of Al-Cu-Ge alloys
Preparation and properties of polycrystalline and nanocrystalline Sm3Co alloys
Influence of external magnetic field on properties of aluminum-doped zinc oxide films prepared by RF magnetron sputtering
Fabrication and application of ordered Si nanopore array induced by Au
First principles calculations of solid phase transition of nitromethane
Multistage microstructural evolution caused by deformation in two-mode phase field crystals
Study on mechanical behavior of the transverse processing on a granular matter layer
When the granular matter is being pushed a certain point can be found, before arriving at which the force increases linearly, and after that it increases exponentially. The granular matter is a large assemblage of solid grains, which are fundamentally different from any other type of matters, such as solid blue and liquids; they have different physical properties. The meso-scale of force chain bridges single particles and granular matter, and leads to unique properties and behaviours of granular matters, thus acts as the key issue in the study of granular matter. In this work, we first find the variation of different forces by simulation. We then propose a discrete element model based on rigorous Hertzian contact law and Mindlin-Deresiewicz contact theory for normal and tangential contact forces, respectively, and then point out that the change of force chain is the key to the granular dynamics. The force distribution and the force chain length distribution are calculated and analyzed to show the change rule and the origin of the drag force.
Valley current mode pulse train control switching converter and its energy model analysis
Influence of temperature change on conductive characteristics of titanium oxide memristor
Circuit parameter calculation based on characteristic parameters and pseudo-impedance of damped oscillation signal
A universal emulator of mem-elements
Study of ZnO photoconductive X-ray detector
Analysis of low-frequency noise in the amorphous indium zinc oxide thin film transistors
A method of removing baseline drift in ECG signal based on morphological filtering
High voltage direct current additional reduced-order controller design based on improved projective control
A new reduced-order controller design method based on improved projective control is introduced. And the low-frequency oscillations can be suppressed by high voltage direct current additional controller through this method. The system reduced mode and relative oscillation frequencies are obtained through TLS-ESPRIT algorithm. Then the controller is designed by improved projective control, after the pole-placement method is applied to obtain a state-feedback matrix. The traditional pole-placement controller based on observer is compared with the projective controller at the same time. The advantages of lower order, stronger robustness and better control effect have been proved through simulation.
Quantum mechanical state equation for describing evolution of projects of financial investment
A new type of conserved quantity deduced from conformal invariance in nonholonomic mechanical system
Conformal invariance and a new type of conserved quantity in nonholonomic mechanical system are studied. The definition and determining equation of conformal invariance for the nonholonomic mechanical system are provided; and the necessary and sufficient conditions that the conformal invariance for a nonholonomic mechanical system should be of Lie symmetry are deduced. With the aid of a new structure equation that the gauge function satisfies, the system's corresponding new conserved quantity is obtained. Finally an example is given to illustrate the application of the results.
Conserved quantities and approximate solutions of a two-dimensional charged coupled oscillator system
Stability and bifurcation control in inertial neuron networks with delays
Based on the second order delay inertia neural network model, this paper puts forward the bifurcation control method: delay feedback control method. Applying the theory of delay differential equations, we give some stability and Hopf bifurcation conditions for the feedback control system. Examples are given to validate that the feedback controller can control the occurrence of bifurcation effectively, expand the stability domain, and change the convergence speed of the network as well.
The traveling wave approximation method for solving solitary wave in Schrödinger disturbed coupled system
Using time delay compensation scheme in dynamic output feedback controller for networked control systems
Data fusaggregation algorithm based on dynamic minimal spanning tree routing protocol
Emergence of scaling in hypernetworks
This paper proposes a unified model for hypernetworks and complex networks, and studies the evolution mechanisms of scale-free hypernetworks and the topological properties of the hypernetwork. We have analyzed the proposed model and calculated the stationary average hyperdegree distribution of the hypernetwork by using a Poisson process theory and a continuous technique. The analytical result agrees well with the simulation. It is shown that the hyperdegree distribution of the dynamic model follows a scale-free law. This paper not only integrates the hypernetwork model, in which one new node forms an edge with some old nodes, and the hypernetwork model, in which some new nodes form an edge with one old node, but also integrates the scale-free model in complex networks.
Studies on vibration response and energy harvesting of elastic-supported bistable piezoelectric cantilever beams
H∞ control for spacecraft chaotic attitude motion by liquid sloshing disturbance observer
Study on the scale-free topology model with strong intrusion-tolerance ability in wireless sensor networks
An improved discrete arnold transform and its application in image scrambling and encryption
To improve the image scrambling and encryption effect in traditional two-dimensional discrete Arnold transform, a new nonlinear transform for image scrambling is proposed which improves the classical discrete Arnold transform with quasi-affine properties, and can be applied in image scrambling and encryption researching. This method first makes good use of the construction thought in classical discrete standard map, and embeds the nonlinear expressions of output results of one congruence equation for classical two-dimensional discrete Arnold transform into the input item of the other congruence equation for two-dimensional discrete Arnold transform. Then a new transform with good nonlinear characteristics is constructed on the basis of classical two-dimensional discrete Arnold transform in order to quickly improve the scrambling effect of the gray image. In the end, through mathematical proof it is shown that the proposed transform no longer has the quasi-affine invariance properties in the existing two-dimensional discrete Arnold transform, but it is still a reversible mapping with periodic properties; and when it is applied in image scrambling encryption, the original image can be restored from the scrambling and encryption in gray image for its periodic properties or inverse transform. Some experimental results show that the proposed nonlinear transform is effective, and can obtain better scrambling and encryption quality than the existing discrete two-dimensional Arnold transform, meanwhile it is more practical than the standard Arnold transform in view of security.
Risk analysis on long inclined-shaft construction in coalmine by TBM techniques based on multiple variables chaotic time series
Study of a spherical vibration-insensitive optical reference cavity
Separating the Z-pinch plasma X-ray radiation and attaining the electron temperature
Theoretical and numerical studies on interactions between high-power microwave and plasma
Research of interactions between high-power microwave and plasma is of importance for both microwave discharge and electromagnetic compatibility. Based on wave equations, fluid equations, and Boltzmann equations of plasma interactively, a theoretical model of interactions between high-power microwave and plasma was established. Combined with characteristic parameters of plasma, the model was solved numerically by the method of finite difference in time domain to analyze variations of plasma electron density and transmission property of high-power microwave. Results show that heating of electrons by incident high-power microwave makes nonlinear effects become obvious in the plasma, and gas breakdown increases plasma electron density which results in the enhancement of reflection of microwave and the of decrease transitivity. The model mentioned above and results related are instructive for protecting against high-power microwave and electromagnetic pulse.
Detection of heavy metal Cr in soil by the femtosecond filament induced breakdown spectroscopy
Study on multi-beam superposition using complementary polarization control plates
Particle-in-cell simulation on surface-wave discharge process influenced by gas pressure and negative-biased voltage along ion sheath layer
Simulation on similarity law of glow discharge in scale-down gaps of rod-plane electrode configuration
On-line measurement on surface electric field of insulator in vacuum based on Kerr effect
Gravity field model calculated by using the GOCE data
Global static gravitational field determined by GOCE satellite data has become a hotspot in current research of geodesy. In this paper, a global static gravity field model entitled SWJTU-GO01S up to the degree and order 210 is recovered based on 12 months of GOCE orbit and gradient data from 2011-02-28 to 2012-03-05 with direct approach. GOCE gradient data are filtered by the zero phase finite impulse band-pass digital filter, and then a gradient observation equation is founded directly in gradiometer coordinates, which avoids high-accuracy gradient component loss in accuracy in the conversion process, while the orbit data is processed with short-arc integral approach. The optimal weight of combination result based on SST and SGG data is determined by variance component estimation and the polar gaps is dealt with the Kuala regularization method. Comparison of internal and external precision of SWJTU-GO01S with EGM2008 and with GPS leveling data of North America, shows that the geoid error and cumulative error of the SWJTU-GO01S model with the degree and order 210 are 2.1 cm and 13.7 cm respectively. Compared with the second generation models released by ESA and ITG-GRACE2010S, the accuracy of the model SWJTU-GO01S is higher than that of the model ITG-GRACE2010S and ESA official time-wise and space-wise model in the above degree and order 150. This study provides a reference to further joint multi-class satellite observation data to recover gravity field models.
Spatial distribution and seasonal variation characteristics of global atmospheric moisture recycling
This paper makes use of new definitions of moisture recycling to study the complete process of global moisture feedback. An accounting procedure based on ERA-Interim reanalysis data is used to calculate moisture recycling ratios. Furthermore, the spatial distribution and seasonal variation characteristics of global moisture recycling are analyzed. Results indicate that: a) Precipitation recycling ratio in different regions show distinct patterns. It is indicated that the dependences of precipitation in different regions on moisture transport are different. b) Spatial distribution of precipitation recycling ratio and evaporation recycling ratio are in good agreement over the lands, but show significant difference over the oceans. c) Seasonal variation characteristics of global moisture recycling ratio are significant, which are stronger in the Northern Hemisphere than in the Southern Hemisphere. d) Main oceanic sources are dominant over continental moisture recycling, and most of the evaporation is transported to other regions by advection. e) Regional moisture recycling ratio not only depends on the factors such as time, location, and shapes of the regions, but also the regional horizontal scale. The moisture recycling ratio curve rises as the regional horizontal scale increases. It is computed that, on the average, precipitation recycling ratio and evaporation recycling ratio of Chinese mainland are respectively about 32.6% and 44.9%; the main source of rainfall in China is moisture evaporated over the South China Sea, the Bay of Bengal, the Arabian Sea and the Western Australia Ocean. The atmospheric moisture recycling model in this paper is based on the atmospheric water balance equation, in terms of good mathematical and physical theory, hence the results are credible.
Characteristics of forecast errors in the National Climate Center atmospheric general circulation model in winter
By using the National Climate Center atmospheric general circulation model (BCC_AGCM) for the second generation monthly dynamic extended range system and the NCEP/NCAR reanalysis data accumulated during 1982-2010, the model forecast errors in winter temperature prediction and their relationship with external forcing factors are analyzed. Result indicates that the model can well reproduce the variation trends of winter temperature over Eurasia region, and the main interannual variability pattern of winter temperature over East Asian monsoon domain can be successfully presented. It reveals that the model has acceptable performances in winter temperature prediction over East Asian monsoon domain, while the forecast errors are still considerable. In spatial distribution, the forecast errors over lands are larger than those over oceans. Meanwhile, the errors at high latitudes are larger than at low latitudes, and they are also closely related to altitude. The principal components of forecast errors have significant association with the sea surface temperature and the sea ice concentration over some key regions, it is shown that the response capability to external forcings is insufficient. This may provide a valuable reference for improving the prediction skill of winter temperature for East Asian monsoon domain, in combination with the model response to external forcings.
Influence of the observation distance on the lightning channel temperature studied by means of spectroscopic diagnosis