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Tourism is the major industry in the Huangshan city. This paper examines time series of tourism to Huangshan from 1979 to 2004. The yearly data set comprises the total arrivals of tourists and total income. A mathematical model which is based on the polynomial approximation and radial basis function is set up to model the tourist flow. The total income and expenditure per tourist are also modeled. The established mathematical models can be used to forecast the tourist flow so that proper planning and management can be arranged.

Studies have shown that numerous operating parameters affecting the proton exchange membrane fuel cell (PEMFC) performance, such as fuel cell operating temperature, operating pressure, anode/cathode humidification temperatures, anode/cathode stoichiometric flow ratios. In order to improve performance of fuel cell systems, it is advantageous to have an accurate model with which one can predict fuel cell behavior at different operating conditions. In this paper, a model using support vector regression (SVR) approach combining with particle swarm optimization (PSO) algorithm for its parameter optimization was developed to modeling and predicting the electrical power of proton exchange membrane fuel cell. The accuracy and reliability of the constructed support vector regression model are validated by leave-one-out cross-validation. Prediction results show that the maximum absolute percentage error does not exceed 5%, the mean absolute percentage error (MAPE) reached 0.68% and the correlation coefficient (R²) as high as 0.998. This implies that one can estimate an available combination of controller parameters by using support vector regression model to get suitable electrical power of proton exchange membrane fuel cell system.

A novel model using support vector regression (SVR) combined with particle swarm optimization (PSO) was employed to construct mathematical model for prediction of the magnetic properties of the NdFeB magnets. The leave-one-out cross-validation (LOOCV) test results strongly supports that the generalization ability of SVR is high enough. Predicted results show that the mean absolute percentage error for magnetic remanence B_r, coercivity H_cj and maximum magnetic energy product (BH)_max are 0.53%, 3.90%, 1.73%, and the correlation coefficient (R²) is as high as 0.839, 0.967 and 0.940, respectively. This investigation suggests that the PSO-SVR is not only an effective and practical method to simulate the properties of NdFeB, but also a powerful tool to optimatize designing or controlling the experimental process.

We use a Lattice Boltzmann Model (LBM) in order to simulate diffuse-charge dynamics in Electric Double Layer Capacitors (EDLCs). Simulations are carried out for both the charge and the discharge processes on 2D systems of complex random electrode geometries (pure random, random spheres and random fibers). The steric effect of concentrated solutions is considered by using a Modified Poisson–Nernst–Planck (MPNP) equations and compared with regular Poisson–Nernst–Planck (PNP) systems. The effects of electrode microstructures (electrode density, electrode filler morphology, filler size, etc.) on the net charge distribution and charge/discharge time are studied in detail. The influence of applied potential during discharging process is also discussed. Our studies show how electrode morphology can be used to tailor the properties of supercapacitors.

The calculation of the coefficients of magneto-optical absorption in semiconductors at different temperatures and pressures is carried out. A formula for the temperature dependence of the oscillations of the combined density of states by the Kane dispersion law is obtained. Mathematical modeling has been carried out that determines the magneto-optical absorption coefficient in semiconductors in the presence of external influences. A new method for determining the magneto-optical absorption coefficient in semiconductors in the presence of pressure and temperature is proposed. The correspondence of simulation results with experimental data is shown.

Historically, although the first indications for the use of lasers in general were in dentistry, coming as a relief from the sound of the drill and mechanical contacts, it still seems somewhat that the entry in various ways of lasers in dentistry has been slower. This is somewhat true for the situation at the continents (e.g. USA much later approved the application relative to Europe). This paper analyzes the potential and existing applications of lasers in dentistry in a wide range of existing types, including interaction with dental tissues, in terms of surgical applications, on living tissue, the prosthetic area of applications and therapeutic doses. There is another special feature that can be recognized is the precise determination of the color of the material (teeth and prosthetics) and in general the determination of the composition of the material including classic, but also modern laser techniques (LIBS, complimentary techniques, tooth tissue, bone) and especially in the case of the first Q switch systems related to pain reduction, because the short pulse favors the intervention rate (ns, ps and fs). Special attention should be paid to modeling of interaction and analysis with the appropriate software support.

In this work, a new model has been developed for calculating the effect of a quantizing magnetic field on the temperature dependence of the two-dimensional combined density of states in direct-gap heterostructures with quantum wells. The temperature dependence of the oscillations of the two-dimensional combined density of states of the quantum well is explained by the thermal smearing of the Gaussian distribution function in a strong magnetic field. Based on the proposed new models, the Landau levels of charge carriers in a direct-gap quantum well are determined in a wide temperature range. The experimental results were interpreted using the oscillations of the combined density of states of the quantum well in a quantizing magnetic field.

Excellent properties of gallium nitride (GaN) make it an ideal material for realizing gas sensors, especially for ammonia (NH${}_3)$ detection. Although many researchers have pursued to describe the characteristics of GaN-based NH₃ gas sensors by different approaches, few models have been reported. In this paper, with the consideration of the exponential distribution of interfacial states, a model for ammonia concentration detection of GaN gas sensors has been presented. The Poisson equation is applied to model the effect of defect states on the potential. By taking advantage of the current-voltage characteristics, the value of Schottky barrier height can be obtained. The concentration of the adsorbed NH₃ gas is derived by exploiting the surface potential. It indicates that densities of acceptor interfacial trap states are in the order of 10${}^{11}\sim 10^{12}$cm${}^{-2}$eV${}^{-1}$. The current increases with the NH₃ concentration at the same applied voltage. In addition, detailed investigations of physical mechanisms and the analysis of the sensitivity have been depicted. It shows that the sensitivity followed an approximately exponential dependence on NH₃ density. Results compared well with experimental data that verify the proposed model and simulation method.

In this paper, we concern with the dynamic behaviors of a high speed mass measurement system with conveyor belt (a checkweigher). The goal of this paper is to construct a simple model of the measurement system so as to duplicate a response of the system. The checkweigher with electromagnetic force compensation can be approximated by the combined spring-mass-damper systems as the physical model, and the equation of motion is derived. The model parameters (a damping coefficient and a spring constant) can be obtained from the experimental data for open-loop system. Finally, the validity of the proposed model can be confirmed by comparison of the simulation results with the realistic responses. The simple dynamic model obtained offers practical and useful information to examine control scheme.