Node importance ranking of complex networks
Identifying the most important nodes, or ranking the node importance by using the method of quantitative analysis in large scale networks are important problems in the complex networks. In this article, the metrics for node importance ranking in complex networks are reviewed and the latest progresses in this field are summarized from two prospects: the network structure and the spreading dynamics. The merits, weaknesses and applicable conditions of different node importance ranking metrics are analyzed. Finally, several important open problems are outlined as possible future directions.
Analysis of the dispersion and interaction impedance for a coupled cavity slow wave structure with double in-line slots in TWT
Study on the design and measurement of dual-directional multi-band metamaterial absorber
Restrain the spurious resonance of second-order fractal frequency selective surface in MMW band
Analytical vectorial structure of Airy-Gaussian beam
Cross polarization effects of vortex beam in reflection
Based on the angular spectrum theory, we establish a propagation model for vortex beam in reflection at an air-glass interface in the paraxial approximation, and investigate the cross polarization effects. When the horizontal polarization vortex beam is incident at different angles, the cross polarization component of the reflected beam shows a double-peak intensity distribution which is similar to the first-order Hermite-Gaussian mode. The distribution of horizontal polarization component is similar to that of the incident beam, and will show a double-peak intensity distribution which is perpendicular to the distribution of cross polarization components at the Brewster incidence. For the incident beam with arbitrary linear polarizations, we find that the polarized direction of cross polarization component is not perpendicular to the incident polarized direction, but exhibits an interesting rotational characteristic. The physical nature of this phenomenon is attributed to the different reflection coefficients of parallel and perpendicular polarizations. Experimental results agree well with our theoretical analysis.
Eye movement analysis for activity recognition based on one web camera
Eye movement information is the key clue for recognizing the vision-dominated tasks, such as browsing the web, or watching a video. However, traditional wearable sensors are invasive and the vision-based eye trackers are very expensive and need time consuming calibration. Therefore, an activity recognition method based on eye movement analysis under one web camera is first proposed and the feasibility is assessed. First, an iris tracking method for the low quality image is proposed to acquire eye movement information. Then, five ten novel features are extracted from the horizontal and the vertical eye movement signals for activity recognition, and the optimal feature subset is selected. Finally, the support vector machine is used to assess the feasibility of the proposed method. Three experiments are designed for different applications: leave-one-out cross-validation, k-fold cross-validation, and validation after respective calibration. Experimental results show that their accuracies are 68.4%, 79.3% and 84.1%, respectively, which demonstrate the promise of eye based activity recognition using one web camera.
PSF estimation via gradient cepstrum analysis for single blurred image
Since single image restoration algorithms using lots of priori information lead to high complexity and low computational efficiency, a gradient cepstrum analysis method is proposed to estimate the point spread function PSF for a single blurred image. Firstly, we present the basic principle of estimating PSF from gradient cepstrum of a single blurred image and use the phase retrieval algorithm to recover phase information of the two-dimensional PSF, which can obtain the estimated PSF rapidly, Secondly, to evaluate the accuracy of the proposed PSF estimation method, the total variation regularized image restoration model coupling with an image gradient fidelity term is established and an alternating direction method with rapid and stable convergence is adopted to optimize the energy function. Both synthetic and real blurred images are tested to verify the performance of our scheme. Results show that our scheme not only can estimate the PSF rapidly and accurately so that it overcomes shortcomings of traditional algorithm with slow convergence, but also suppresses ringing effects to preserve information in edges. These advantages provide theoretical and technical foundation of the real engineering requirement in single image deblurring, especially for large scale images.
Theory of complex ridgelet transform based on the entangled state
Entanglement properties of two coupled atoms in Kerr medium
Experimental research on retrieval efficiency of atomic spin wave based on electromagnetically induced transparency
The instantaneous linewidth measurement of DFB laser with ultrashort delay
Experimental characterization of polarization gain properties of 808nm semiconductor laser and analysis of energy band based on amplified spontaneous emissions from double facets
A measurement method of cell gap for liquid crystal lens
Investigation on large-mode-area flat-topped optical fiber with microstructured core and its transmission characteristics
An algorithm for image reconstruction based on lp norm
Investigation on characteristics of flow in microchannels with random surface roughness
Stability of liquid droplet containing insoluble surfactant spreading over corrugated topography
Study the coupling effect of shear and electric field on rheological behaviors of liquid crystals
Exchange bias effect in single crystalline phase MnO nanoparticles
Molecular dynamics simulation of tensile deformation mechanism of the single crystal tungsten nanowire
First principles studies of phase transition and mechanical properties of uranium
Isotropic compression of colloidal crystal in electric field between plate electrode
Single event effect of 3D H-gate SOI NMOS devices in total dose ionizing
Numerical investigation of bubble nucleation process using the lattice Boltzmann method
Structural phase transition of Ru at high pressure and temperature
Investigation on visible emission and n-type conductivity of ZnO thin films annealed at different temperatures
Molecular simulations of adsorption and separation of natural gas on zeolitic imidazolate frameworks
Single-vacancy-induced transformation of electronic properties in armchair graphene nanoribbons
First-principles study of structural stability and electronic properties of tetragonal and orthorhombic as well as monoclinic K0.5Na0.5NbO3
Plasmonic excitations in mesoscopic-sized atomic chains：a tight-binding model
Surface states of InAlN film grown by MOCVD
Analysis of characteristics and key influencing factors in magnetomechanical behavior for cable stress monitoring
Preparation of nanostructured GaN films and their field emission enhancement for different substrates
Broad band infrared optical properties of Cr4+-doped Li1.14Zn1.43SiO4 transparent glass-ceramics
Cr4+-doped transparent Li1.14Zn1.43SiO4 glass-ceramics were prepared by high-temperature melting and subsequent heat-treatment, and the crystalline, microstructural, and luminescence properties of the products prepared by different-temperature heat-treatment were investigated. Results showed that the glass-ceramics heat-treated at 580 ℃ for 2 h contained nano crystallines of about 5 nm in size, and a broadband infrared emission centered at 1226nm with full width at half maximum of more than 230 nm and a decay time of about 200.07 μs were observed by exciting with an 808 nm laser diode. Mean while, it is believed that the crystalline field environment of Cr4+ is changed with the increase of heat-treatment temperature, which results in blue shift and red shift of absorption and fluorescence spectra, respectively.
Photoluminescence properties of selenium nanocrystals on Si(100) substrate formed by rapid thermal annealing
We have investigated the structure and photoluminescence (PL) properties of Se nanocrystals (NCs) obtained by rapid thermal annealing of a-Se films on Si substrate. The size of Se NCs in a trigonal phase increases linearly with increasing temperature. Moreover, three PL peaks located at 1.4, 1.7 and 1.83 eV are observed, which are attributed to the emission of defects in amorphous Se, donor-acceprter pair (DAP) recombination at the interface of amorphous Se and Se NCs, and interband transition of Se crystals, respectively.
Study on microstructure and properties of Mg2(Si,Sn) compound phase in Mg-Sn-Si magnesium alloy
Microstructure, characteristic and metamorphism of Mg2(Si,Sn) compound phase are studied in as-cast Mg-Sn-Si alloy. The results indicate that Sn atom can replace the partial Si of Mg2Si then form Mg2(Si,Sn) compound phase, and structure of the ternary compound is the same as Mg2Si and Mg2Sn, all belong to face-centered cubic. The element content of Mg2(Si,Sn) phase is not invariable, the Mg2(Si,Sn) phase with high Si content is in Si enrichment region, while it with low Si content is in Si poverty region. The property of Mg2(Si,Sn) phase with high Si content is close to Mg2Si phase, the property of the phase with high Sn content is close to Mg2Sn phase. In experiments, the nano-hardness, elastic modulus, vickers hardness and other physical properties of Mg2(Si,Sn) phase are between Mg2Si phase and Mg2Sn phase, in the metamorphism process of Chinese-script-like Mg2Si phase, Mg2(Si,Sn) compound phase plays a role as a bridge.
Hydrothermal synthesis of K, Na doped Cu-S nanocrystalline and effect of doping on crystal structure and performance
Cuprous sulfide (Cu2S) nanocrystals and K or Na doped KCu7S4 nanowires and NaCu5S3 micro-nanospheres have been synthesized successfully by using a simple hydrothermal method, using KOH or NaOH as mineralizing agent, CuCl2·2H2O and S powders as copper and Sulfur sources, respectively. The structure and morphology are characterized and analyzed by X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The results reveal that under conditions that the amount of KOH is below 1g or the amount of NaOH below 2 g, the product is of the orthorhombic chalcocite Cu2S, while with high alkali amount (no less than 3 g), K+ or Na+ is successfully incorporated into the Cu-S structure; KCu7S4 has the pure tetragonal single crystal structure, and its uniform nanowires can be up to several tens of micrometers in length. Na doping has no effect on the morphology of the product, which forms the hexagonal NaCu5S3. The formation and growth of the product are closely related to the reaction temperature, reaction time and mineralizing agent. And, the formation and doping mechanisms are discussed. Finally, the influence of the alkali metal ion doping on the optical properties of the product is investigated. The diffuse reflectance spectra demonstrate that the optical band gaps of Cu2S, NaCu5S3 and KCu7S4 nanocrystallines is 1.21, 0.49, 0.42 eV, respectively. And K+ or Na+ doping greatly affects the optical characteristics.
Structural characterization and magnetic properties of perpendicularly magnetized MnAl films grown by molecular-beam epitaxy
Enhanced third harmonic generation by localized surface plasmon excitation
We experimentally achieved optical third harmonic generation (THG) from two-dimensional periodically arrayed gold-island films. The gold-island films were fabricated using micro-spherical lithography. By using a reflection-type optical system, these arrays can produce significant THG with the help of a spectrum-resolved femto-second laser. At the localized surface plasmon (LSP) excitation wavelength of the fundamental wave, THG is greatly enhanced due to the strong light localization effect. The radiation direction of THG satisfies the momentum matching condition.
Effect of interface energy anisotropy on the dendritic growth in directional solidification
The dendritic growth patterns in directional solidification with different amplitudes of solid-liquid interface energy anisotropy were investigated using the two-dimensional cellular automata (CA) model. It is shown that when the preferred growth direction of the crystal was the same as the direction of thermal gradient, the solidification pattern would transform from seaweed to dendrite with the increase of amplitude of interface energy anisotropy. The amplitude of interface energy anisotropy could also influence the morphology of dendritic tips. As the amplitude of interface energy anisotropy increased, the dendritic tip radius, the liquid concentration ahead of the tip and the tip undercooling decreased. A power law relationship evisted between the stability parameter of dendritic tip and the amplitude of interface energy anisotropy in directional solidification. The primary arm spacing changed little with the increase of interface energy anisotropy. When the angle between the preferred growth direction of the crystals and the direction of thermal gradient was-40°, and the amplitude of interface energy anisotropy increased, the solidification pattern would transform from seaweed to degenerated dendrite and finally to tilted dendrite.
Injection-locking of magnetrons with matched impedance
The impact of interface charges at the heterojunction on the carriers transport in abrupt InP/InGaAs heterojunction bipolar transistor
The carriers transport at the base-emitter interface of abrupt heterojunction bipolar transistors (HBTs) is controlled by thermionic emission and tunneling, which depends on the form and height of the energy barriers. The interface charges at the heterojunction disturb the energy barriers, thus bringing about the change of the electrical characteristics of HBT. Based on thermionic-field-diffusion model which combines the drift-diffusion transport in the bulk of the transistor with the thermionic emission and tunneling at the interface, a conclusion can be drawn that the positive interface charges can improve the electrical characteristics of abrupt InP/InGaAs HBT, while the negative interface charges deteriorate the devices.
Design of silicon based germanium metal-semiconductor-metal photodetector enhanced by surface plasmon resonance
Nonspecific adsorption of charged mesoporous nanoparticles on supported thiol/lipid hybrid bilayers
Mesoporous silica nanoparticles (MSN) with cationic and anionic surface charges were synthesized, Their adsorption behaviors to the supported lipid membranes at different pH values were also studied using QCM-D. We found that NH2-MSN could be adsorbed onto the membrane at pH values from 4 to 8, while the adsorption of COOH-MSN onto the membrane could not occur due to its charge being always the same as that of the membrane at any pH values. These results might provide the information for understanding and predicting the interactions between nanoparticles and cell membranes, and could be effectively used in drug delivery systems and disease treatment.
SPFGO effects on the electroluminescence and photovoltaic response in conjugated polymers
This paper studies the influence of poly [2-methoxy-5-(2’-ethylhexyloxy)-1, 4-phenylenevinylene] (MEH-PPV) on solution-processable functionalized graphene oxide (SPFGO) composite film-based organic light emitting Diode (OLED) and organic photovoltaic (OPV) performance for different SPFGO concentrations. There is a strong quenching of photoluminescence when MEH-PPV is doped with SPFGO, which means there is a strong transfer of electron and energy between MEH-PPV and SPFGO. Doping SPFGO in MEH-PPV can improve the performance of OLED at low concentration, and the performance will be the best when the concentration of SPFGO is 0.2%; however, the performance of OPV remains unchanged. The performance of OPV could be improved by high doping concentration of SPFGO, the performance will be the best when the concentration of SPFGO reaches 15%, and there is a quenching in the electroluminescence (EL) of OLED. As shown in the statistics of the experiment, SPFGO can increase the injectivity of carriers, and when the SPFGO is of low concentration, it can increase the luminous intensity of OLED and reduce the threshold voltage. SPFGO can act as an electron acceptor, and when the concentration of SPFGO is high, the exciton dissociation at MEH-PPV/SPFGO interface can be improved, and the performance of OPV can be also improved. Therefore, the concentration of SPFGO should be the main factor in adjusting the performance of OLED and OPV separately.
Congestion and efficiency in complex traffic and transportation networks
Perturbation method of travelling wave solution for (2+1) dimensional disturbed time delay breaking solitary wave equation
Homotopic approximate solutions for a class of generalized perturbed Kdv-Burgers equation
The homotopy analysis method for a class of jamming transition problem in traffic flow
Electromagnetic scattering from missile target above sea surface with finite element/boundary integral method
Wigner-Yanse skew information of the system with the electromagnetically induced transparency
The quantum-information theoretic notation of the Winger-Yanse skew information has been used to analyze the process of information transfer between probe fields and atomic ensemble in the electromagnetically induced transparency. It is well known that the skew information is a well-defined measure that quantifies the amount of the information a quantum state contains. We have calculated the dynamical skew information of the probe fields and the atomic ensemble, and found that the information for the individual atom is dependent of the numbers of the particles and the photons, as well as the state of the probe field. For a sufficiently weak coherent driving field, the dark-state polaritons is a purely atomic state with no photons in the composite system, and the information of the individual atom reaches the maximum value. However, the information of the probe field is not completely transferred into the atomic ensemble.
Application of the composite adiabatic passage technique in the Landau-Zener model with harmonic interaction modulation
Three-party quantum key agreement with Bell states
A three-party quantum key agreement protocol based on EPR pairs is proposed, in which the three participants have equal status in the protocol and each participant is capable of contributing to the shared secret key in the same degree. In addition, any one or two parties cannot predetermine the value of shared key alone. The security analysis shows that our protocol can resist the outside attack and the dishonest participants attack.
A model of quantum signaling repeater and its parameters simulation
A modified chaotic ant swarm optimization algorithm
Realization of synchronization between hyperchaotic systems by using a scheme of intermittent linear coupling
A modified feedback controlled car-following model considering the comprehensive information of the nearest-neighbor leading car
A new data assimilation method using complex-variable differentiation
A new method for data assimilation is proposed using complex-variable differentiation (CVD), which can be used to estimate the initial conditions of the nonlinear physical system governed by the following equation: . Firstly, the gradient analysis of cost function in variational data assimilation is transformed into function numerical computation in complex domain, and the value of gradient is computed more efficiently and exactly. Secondly, the new algorithm of data assimilation is developed by combining an accurate gradient information from CVD with the classical optimization method. Finally, numerical simulations of typical chaotic systems and a humidity evolution equation with physical “on-off” process show that the new data assimilation method can reconstruct initial conditions of the nonlinear dynamical system very conveniently and accurately.
Construction of a class of chaos systems with Markov properties
Fuzzy adaptive extended Kalman filter SLAM algorithm based on the improved wild geese PSO algorithm
Dynamic behavior and chaos synchronization of a simple nonlinear time-delayed system
Hopf bifurcation and chaotic properties of a simple second order time-delayed system, which includes bifrucation point, bifurcation direction and the stability of bifrucating periodic solutions, are analyzed. We obtain analytically the phase trajectory equations when the delay degenerates. Furthermore, through bifurcation diagram drawn by means of numerical simulation, the route from period-doubling bifurcation to chaos is reaveled; using single linearly combinating signals and the feedback control method, we achieve partial synchronization of the system. Combining the active-passive method with the linear feedback method, we have realized complete synchronization. In addition, we have designed and built an electronic experimental line, from which the same result as the theoretical analysis or numerical results are obtained.
Compound bursting in an electrical coupling model with three different time scales
A new method to directly observe the state of a single-variable nonlinear system with oscilloscope
In order to solve the problem why it was hard to observe the single-variable nonlinear system, this article proposed the 45° line method. In this method, the continuous signal changing with time was transformed into dots on the 45° line of the rectangular coordinates, so that it could be directly displayed on a general dual-trace oscilloscope (either analog or digital). In this way, it is convenient to directly observe and analyze various states of single-variable system while the system is running, such as the periodical stable states, the local and global non-stable states. The mechanism of this method was expounded in this paper. In addition, the key issues in physical circuit design and implementation of this method were researched and solved, i.e., the useful signal which reflected the state of the system could be extracted from the continuously changing signal. Since the Chua’s circuit is a typical nonlinear system, and it could produce abundant states with variation of parameters, so it was chosen as the system under test to conduct a great number of physical experiments. The experimental results confirmed the effectiveness and practicability of this method.
Sampled-data synchronization control of chaotic systems based on min-max approach
For the chaotic systems with disturbance, a sampled-data controller is designed to achieve chaotic synchronization. Firstly, to handle the discontinuity introduced by the sampling activities, the input-delay approach is introduced to transform the discontinuous chaotic systems into continuous ones. Secondly, the worst possible case of performance is considered according to min-max robust strategy. Then the sufficient conditions for global asymptotic synchronization of such chaotic systems are derived and expressed in terms of linear matrix inequality (LMI). The proposed algorithm can achieve synchronization of the sampled-data chaotic systems for all admissible disturbances at the pre-computed set of disturbance realizations. The effectiveness is finally illustrated via numerical simulations of chaotic Chua’s circuit, and the simulation results show that the proposed algorithm is suitable for secure communication.
Chaos synchronization of FitzHugh-Nagumo neurons via backstepping and adaptive dynamical sliding mode control
Shock pressure in femtosecond laser ablation of solid target
Uncertainty analysis of the measured spectrum obtained using transmission grating spectrometer
Arbitrary and absolute length measurement based on femtosecond optical frequency comb
Experimental research on the technique of magnetic flux compression by explosive cylindrical implosion
The cylindrical magnetic flux compression by explosive implosion (MC-1) is a kind of unique high energy density dynamic technique. A metal cylinder was driven by explosive implosion to compress the primary magnetic flux inside and an ultrahigh magnetic field was realized, which could be used to achieve effective isentropic compression of the sample. This technique has anigue characters like ultrahigh isentropic pressure and ultrahigh magnetic field, and would find wide usage in areas like high pressure physics, new material synthesis and ultrahigh magnetic field physics. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP) has begun to make experiments on MC-1 since 2011 and a one-stage MC-1 set-up has been built up. The primary experimental results including the movement of liner and typical "turn-around" character in MC-1 experiment were observed and recorded. In the experiment a dynamic magnetic field of about 430T was obtained. The MC-1 process was numerically simulated by the one-dimensional MHD code and the simulations are in accord with experiments. Numerical simulations show that this technique has advantages in isentropic compression of materials as compared with normal implosion experiment.
Noether-Lie symmetry and conserved quantities of Nielsen equations for a singular variable mass nonholonomic system with unilateral constraints
X-ray emission of C6+ pulsed ion beams of CSR impacting on Au target
Viscosity measurements using a cylindrical resonator
The Bohm criterion for a plasma sheath with two species of charged dust particles
Backscattered Light diagnostic technique on Shen Guang-III prototype Laser Facility
Experimental study on current division of nested wire array Z pinches
Two-dimensional simulation of atmospheric pressure cold plasma jets in a needle-plane electrode configuration
Simulation study on hydrogen penning source discharge at low pressure
A new method of forecasting initial formation temperature during the whole drilling process based on proportional-integral control principle