Silicon nitride ceramics with MgSiN2 as additives were sintered by hot pressing at 1600° ~ 1750 °C for 1-12 h under uniaxial pressure of 20 MPa. The specimens were characterized by x-ray diffraction, scanning electron microscopy, transmission electron microscopy and photothermal deflection spectroscopy. After sintered at 1750°C for 1 h, the thermal conductivity of the material was 90 W·m-1·K-1. The thermal conductivity could remarkably increase to 120 W·m-1·K-1 by prolonging the dwell time from 1 h to 12 h. The present work demonstrated that MgSiN2 additives were effective to improve the thermal conductivity of β-Si3N4 ceramic.

SrMoO4:Eu3+ micro-spheres with well morphology were fabricated by a one-step and template-free ultrasonic spray pyrolysis method using strontium nitrate and ammonium molybdate as precursors. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra (PL). The XRD results indicate that all the XRD peaks can be indexed as SrMoO4 with a pure tetragonal scheelite structure. The SEM photographs show that the sample particles are spheres with regular spherical shape. The excitation and emission spectra demonstrate that the phosphors could be excited effectively by the ultraviolet light with wavelength 394 nm or visible blue light with wavelength 466 nm, and the highest emission peak locates at 615 nm.

This paper presents an algorithm for detecting the small infrared target under complex background. An method, Local Mutation Weighted Information Entropy (LMWIE), is proposed to suppress background. Then, enhance targets’ gray value by calculating the local energy. For the problem that the gray value of noises is enhanced with the gray value improvement of targets, image segmentation bases on the adaptive threshold. Experiment results indicate that it is a robust and effective small target detection algorithm.

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The red long persistent phosphors (Sr 1-x Ca x) S: Eu 2+ , Dy 3+ (0≤x≤0.4) were prepared by sol-gel thermolysis method under reducing atmosphere. The results of XRD indiSuperscript textcated that the phosphor of the major phase was SrS (0≤x≤0.4) and the diffraction peak positions shift to higher angles with increase in x. The spectral properties are measured, and it found that the emission wavelength and decay properties of the phosphor varied with x. With increasing x, the luminescence intensity increased at beginning ,then decreased, and at x=0.3, the initial brightness and the afterglow time of the phosphor became maximal.