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According to the nickel foam surface defect images with the typical characteristics of complex geometry and texture distribution, a nickel foam surface defect detection method based on spatial-frequency multi-scale block local binary pattern is proposed. First, nonsubsampled contourlet is used to carry out foam nickel image multi-scale decomposition, and therefore, low-frequency sub-band images and high-frequency sub-band images are obtained. The multi-scale block local binary pattern is then used to extract the feature histogram vectors of each block region of low- and high-frequency sub-bands, and the histogram feature vectors of the whole image after cascade are formed. The kernel principal component analysis and support vector machine are adopted to reduce the dimension of the feature histogram vectors and used for the defect classification. Experimental results show that the proposed method of feature extraction can extract more detailed texture information, and the average recognition rate reaches to 90%, which meets an enterprise’s needs.

The paper investigated the effect of chemical etching and temperature on the optical properties and microstructures of porous silicon layer fabricated by the pulse electrochemically etching by means of the reflectance spectroscopy and photoluminescence spectroscopy. The relationship between the optical thickness (nd) and refractive index n of porous silicon layer and the chemical etching time and temperature has been detailedly studied. With increasing the chemical etching times, the reflectance spectra exhibit the more intense interference oscillations, which mean the uniformity and interface smoothness of porous silicon layers become better, meanwhile, results in decreasing the optical thickness and refractive index, indicating a higher porosity. Moreover, the intensity of photoluminescence spectra increases, and the envelope curves of photoluminescence spectra exhibit a trend of red-shift, which implied the average diameter of silicon nanocrystallite became larger. The chemical etching rate of the optical thickness intensely increases with the chemical etching temperature.

We present two schemes for efficient implementation of a nonlocal gate with nonmaximal entanglement. The main strategy of the schemes is local conversion of pure states, which consists of a generalized measurement described by a positive operator-valued measure (POVM), one-way classical communication, and corresponding unitary operations. First, we discuss the way to generate determinately the nonlocal gate via any pure shared entangled state combined with entanglement-assistance. Then we propose the other way to generate probabilistically the nonlocal gate via any pure entangled state with the aid of ancillary particles.