Modern Physics Letters B

Based on tremendous real data, a macroscopic model is established, which can depict the process of volatile organic compound (namely, VOC) emissions. Different from previous work, a complete set of sources is taken into account rather than only an isolated source. These data have been processed to support the sample set in order to prove the validity of the theoretical analyses. Besides, the relationship between the industrial production and VOC emissions of industrial source is discussed and depicted. Furthermore, the relationship between the electronic industrial production and VOC emissions is emphasized and calculated. VOC emissions per unit production is investigated. Additionally, the relationship between the number of sample points in the sample set and VOC emissions is illustrated. Then, the control strategy of VOC emissions is proposed by calculating the optimal solutions of each sample set. It is found that the lower the slope of optimal solutions, the lower the average VOC emissions, the better the VOC emissions control effect.

We report, in this paper, a recent study on the dynamical mechanism of Brownian particles diffusing in the fractional damping environment, where several important quantities such as the mean square displacement (MSD) and mean square velocity are calculated for dynamical analysis. A particular type of backward motion is found in the diffusion process. The reason of it is analyzed intrinsically by comparing with the diffusion in various dissipative environments. Results show that the diffusion in the fractional damping environment obeys the Langevin dynamics which is quite different form what is expected.

Chen–Lee–Liu (CLL) lattice equation is an integrable discretization of the CLL equation which can be used to model the evolution of the self-steepening optical pulses without self-phase modulation. In this paper, the discrete N-fold Darboux transformation (DT) is used to derive the discrete kink multi-soliton solutions in terms of determinant for CLL lattice equation. Soliton fission and fusion interaction structures of such solutions are shown graphically. The details of their evolution are investigated by using numerical simulations, showing that a small noise with amplitude less than or equal to 0.01 produces a strong oscillation and instability of these kink soliton solutions. The discrete generalized perturbation $(n,N-n)$-fold DT is constructed to express some rational solutions in terms of the determinants of CLL lattice equation by modifying the discrete N-fold DT. Infinitely many conservation laws for CLL lattice equation are constructed based on its Lax representation. Results in this paper might be helpful for understanding the propagation of optical pulses.

Face recognition is a vastly researched topic in the field of computer vision. A lot of work have been done for facial recognition in two dimensions and three dimensions. The amount of work done with face recognition invariant of image processing attacks is very limited. This paper presents a total of three classes of image processing attacks on face recognition system, namely image enhancement attacks, geometric attacks and the image noise attacks. The well-known machine learning techniques have been used to train and test the face recognition system using two different databases namely Bosphorus Database and University of Milano Bicocca three-dimensional (3D) Face Database (UMBDB). Three classes of classification models, namely discriminant analysis, support vector machine and k-nearest neighbor along with ensemble techniques have been implemented. The significance of machine learning techniques has been mentioned. The visual verification has been done with multiple image processing attacks.

In order to depict the effect of driver’s memory on car-following behavior, a new kind of car-following model is proposed by using fractional order differential equation in this paper. Its dynamic equation is defined by Caputo fractional order derivative. And the order of derivative is the measurement of driver’s memory. In addition, discrete formulas of the position and velocity of the new model are given. The Optimal Velocity (OV) model is taken as an example to introduce how to get the fractional order car-following model from an ordinary model. The simulation results show that the Fractional Order Optimal Velocity (FOOV) model is more stable, and it can avoid unrealistic acceleration values of the OV model in the cases of starting and braking processes. Moreover, magnitudes of the speed and headway fluctuation of the FOOV model with a suitable order are smaller than those of the OV model. This indicates that the memory characteristic of drivers increases the stability of traffic flow.

976 nm fiber Bragg grating (FBG) external cavity laser is the core component in erbium-doped fiber amplifiers (EDFA). In this paper, the theory model of FBG is modeled by transfer matrix method (TMM). The effects of Bragg grating length and modulation depth on the reflectivity, grating spectrum width and wavelength have been investigated. Then 976 nm laser modules with different grating reflectivity, i.e. 4%, 6%, 8% and 10% have been fabricated. By improving the reflectivity of FBG, the side-mode suppression ratio (SMSR) has been optimized to above 40 dB, and the threshold current decreases. The temperature cycling test indicates that the peak wavelength has a change rate $\sim$0.0095 nm/${}^{\circ }$C.

In this paper, Ag–Ce–ZnO nanocomposites with average particle size of about 50 nm were prepared by direct precipitation method. In order to solve the problem of agglomeration, the nanocomposites with the average particle size of about 30 nm were obtained by treating the nanocomposites with surfactant sodium polyacrylate (PAAS). The effect of surfactant PAAS on the content of hydroxyl radicals produced by nanocomposites was determined by UV spectrophotometry and fluorescence spectrophotometry, and the effect of PAAS on the dispersion effect was obtained indirectly. The experimental results showed that the addition of surfactants’ PAAS effectively reduced the average particle size of nanocomposites, increased the content of hydroxyl radicals, and made the nanocomposites have good dispersing effect.

Identifying the influential nodes in complex networks is a challenging and significant research topic. Though various centrality measures of complex networks have been developed for addressing the problem, they all have some disadvantages and limitations. To make use of the advantages of different centrality measures, one can regard influential node identification as a multi-attribute decision-making problem. In this paper, a dynamic weighted Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is developed. The key idea is to assign the appropriate weight to each attribute dynamically, based on the grey relational analysis method and the Susceptible–Infected–Recovered (SIR) model. The effectiveness of the proposed method is demonstrated by applications to three actual networks, which indicates that our method has better performance than single indicator methods and the original weighted TOPSIS method.

The optical performance of RGB LEDs used in displays is highly sensitive to the drive current and ambient temperature. The emitting intensity and dominant wavelength of RGB LEDs are investigated with the various currents and temperatures, and then the relevant mathematic models are proposed and summarized. Hence, the emitting intensity and dominant wavelength of RGB LEDs under any operating condition can be known from these models.

In this paper, a variable speed limit control approach for improving the efficiency of signalized intersection is proposed from the cyber-physical view. In the proposed control scheme, vehicle-to-vehicle communication is being utilized fully such that the preceding vehicle’s optimal information is exploited for optimizing the motion of the current vehicle. To prepare the control scheme for dynamical optimization, nonlinear model predictive control technique is used to optimally control vehicle speed limit and a new traffic model is constructed by considering vehicle dynamics. Moreover, this paper evaluates the influence of communication distance on the traffic. The results show that extending communication distance in the vicinity of signalized intersection can improve vehicles’ average fuel economy.

The adiabatic sound velocity of liquid argon is calculated by means of classical molecular dynamics simulations via the COMPASS force field, at the temperature of 388 K and the pressure range of 0.5–2.0 GPa. The isothermal sound velocity of liquid argon is obtained from the fluctuations of the supercell volume via Fluctuation Formula. Then, the adiabatic sound velocity is calculated from isothermal sound velocity by the Landau–Placzek ratio derived from the dynamic structure factor of the system. The calculated adiabatic sound velocities of liquid argon are in good agreement with the former Brillouin scattering measurements.

Electronic structures and optical properties of zinc-blende aluminum nitride doped with transition metals are investigated. Lu-doped system possesses the most considerate stability with the lowest formation energy of −9.033 eV compared to others. Band structures of systems are introduced to investigate a more excellent semiconductor capacity for Re-doped system with a band gap $(E_G)$ of 0.689 eV, with others having band gaps of 2.120, 2.159, 1.806, 1.837 and 0.879 eV, respectively, much smaller than that of pristine one, 3.113 eV. Moreover, absorption spectra curve reaches the lowest peak of $2.558\times 10^5{\mathrm{\text{cm}}}^{-1}$ for Os-doped system; simultaneously, the system exhibits a relatively negative reflectivity spectra and dielectric loss of 5.620 eV that are extensively expected in solar cell industry, predicting its broad scope of application prospects in photoelectric and microelectronic devices.

In this paper, a novel metal-matrix phononic crystal with a low-frequency, broad and complete, locally-resonant band gap, which includes the in-plane and out-of-plane band gaps, is investigated numerically. The proposed structure consists of double-sided single “hard” cylinder stubs, which are deposited on a two-dimensional locally-resonant phononic-crystal plate that consists of an array of rubber fillers embedded in a steel plate. Our results indicate that both the out-of-plane band gap and the in-plane band gap increase after introducing single “hard” cylinder stubs. More specifically, the out-of-plane band gap is increased by the out-of-plane analogous-rigid mode, while the in-plane band gap is increased by the in-plane analogous-rigid mode. The out-of-plane and the in-plane analogous-rigid mode are formed after introduction of the single “hard” cylinder stub. As a result, a broad, complete locally-resonant band gap in the low frequency is obtained due to the broad in-plane and out-of-plane band gaps overlapping. Compared to the classical double-sided stubbed metal-matrix phononic-crystal plate, the absolute bandwidth of the complete band gap is increased by a factor of 4.76 in the proposed structure. Furthermore, the effect of simple “hard” stubs on complete band gaps is investigated. The results show that the location of the complete band gaps can be modulated using a low frequency, and the bandwidth can be extended to a larger frequency range using different “hard” stubs. The new structure provides an effective way for metal-matrix phononic crystals to obtain broad and complete locally-resonant band gaps in the low-frequency range, which has many applications for low-frequency vibration reduction.

In this paper, the new type of coupled states localized near the nonlinear boundary media and propagating along it are considered. The boundary of nonlinear media with different parameters of anharmonicity of interatomic interaction creates a disturbance of medium characteristic. It is expected that the particle has a complex linear law of dispersion with several branches of different parameters in a model proposed in this paper. The problem is reduced to the solution of the nonlinear Schrödinger equation with boundary conditions for a special kind. Explicit solutions of nonlinear Schrödinger equations satisfying the boundary conditions were found. It is shown that the existence of nonlinear localized excitations of several types is possible. They have a soliton-like profile in the direction perpendicular to the boundary. The structure and shape of the localized states is determined by the anharmonicity parameters and the intensity of interaction of the excitations with the plane defect. The equations determining the energy of the wave localized along the media boundary for a fixed direction of its wave vector are derived. Dependences of the wave numbers from the parameters of the system for localized states in various private cases are explicitly expressed.