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Shi L.,Huaihai Institute of Technology | Zhou Z.,Huaihai Institute of Technology | Tang B.,Lianyungang Teachers College
Applied Optics | Year: 2012

We demonstrate the optimization of plasmonic thin-film solar cells with broadband absorption enhancements. The solar cells model system consists of a three-dimensional, periodic array of Ag/silica cylinders on a Si film supported by a silica substrate. Particle swarm optimization (PSO) and the finite-difference time domain (FDTD) are combined to achieve the maximum absorption enhancement (Ehm). Through optimization, the optimal system parameters, such as the height and diameter of Ag and the silica cylinder, and the period of periodic array, were obtained. Following this approach, we can attain a 321% enhancement in the integrated quantum efficiency as compared to a cell without metallic structures. The full-band absorption enhancement arises from the near-field enhancement and multiresonant guided modes in the Si waveguide. © 2012 Optical Society of America. Source


Yan M.,Lianyungang Teachers College
Journal of Computers (Finland) | Year: 2013

Classification of nonlinear high-dimensional data is usually not amenable to standard pattern recognition techniques because of an underlying nonlinear small sample size conditions. To address the problem, a novel kernel fuzzy dual discriminant analysis learning based on a rank symmetric relation is developed in this paper. First, dual subspaces with rank symmetric relation on the discriminant analysis are established, by which a set of integrated subspaces of within-class and between-class scatter matrices are constructed, respectively. Second, a reformative fuzzy LDA algorithm is proposed to achieve the distribution information of each sample represented with fuzzy membership degree, which is incorporated into the redefinition of the scatter matrices. Third, considering the fact that the kernel Fisher discriminant is effective to extract nonlinear discriminative information of the input feature space by using kernel trick, a kernel algorithm based on the new discriminant analysis is presented subsequently, which has the potential to outperform the traditional subspace learning algorithms, especially in the cases of nonlinear small sample sizes. Experimental results conducted on the ORL and Yale face database demonstrate the effectiveness of the proposed method. © 2013 ACADEMY PUBLISHER. Source


Wang P.,Nanjing Normal University | Wang P.,Lianyungang Teachers College | Zhang Z.,Nanjing Normal University
International Journal of Computer Mathematics | Year: 2010

In this article, we use the quadratic finite volume element method (FVEM) to solve the problem of the air pollution model, choose the trial function spaces as the Lagrange quadratic element function spaces and the test function spaces as the piecewise constant function spaces, then get the error estimates of L2 and H1. Finally, by numerical experiments, we analyse and compare the FVEM with the finite difference method, and the numerical results we get show that the FVEM is much better and more effective, so this article has some practical significance in the improvement and control of air pollution. © 2010 Taylor & Francis. Source


Tang B.,Lianyungang Teachers College | Tang X.,Nankai University | Wang G.,Jiangsu University
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011

Details on alternately layered composite cycle structure of two-dimensional photonic crystal, which was formed by the cylinder body thickness and dielectric constant difference, were discussed in the essay. Its transmission characteristics were studied numerically by using the plane wave expansion method. The numerical results indicate that in the layered complex period photonic crystal transmission spectra with different two-dimensional cylindrical radius, the band gap position, width and conduction mode appearance associates with the differences of spacer columns thickness. The greater the difference is, the smaller the photonic band gap is, and the central frequency location moves to lower dielectric constant layer. Also, in different complex periodic structure, the greater the dielectric constant difference is, the smaller the photonic band gap width is. Likely, the center frequency moves to lower frequency. When the spacer column layer reaches a certain value, no conduction mode will exist. Under the same difference conditions, forbidden band not only associates with conduction mode, but also with the lattice structure type and the display order of electromagnetic wave incident surface column. The related conclusions can be applied to the expansion of two-dimensional photonic crystal applications as a new theoretical basis. Source


Shi L.,Huaihai Institute of Technology | Zhou Z.,Huaihai Institute of Technology | Tang B.,Lianyungang Teachers College
Optik | Year: 2014

We present a numerical study on the optimization of plasmonic thin-film solar cells with full band optical absorption increased in all polarization using plasmonic backcontact gratings. Particle swarm optimization (PSO) and the finite-difference time domain (FDTD) are combined to achieve the maximum absorption enhancement. Through optimization, we obtained approximately a 288% average absorption enhancement, 304% and 273% absorption enhancement for TE- and TM-polarized illumination as compared to a bare cell. The corresponding optimal design parameters of plasmonic solar cell are P = 442 nm, h4 = 283 nm, h5 = 191 nm and w=238 nm. The full band absorption enhancement arises from the waveguide-plasmon-polariton, Fabry-Pérot (FP) cavity mode and multiresonant guided modes. The average absorption enhancement under an unpolarized illumination is almost immune to the incident angle ranging from -40 to 40. If the thickness of the light absorbing layer is increased, the absorption enhancement could be reduced significantly. And the average absorption enhancement is maximum (2.88) when the thickness of Si layer is 100 nm. © 2013 Elsevier GmbH. Source

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