基于局部相关性的遥感图像全色锐化算法

为了增强多光谱图像的空间分辨率同时避免出现严重的光谱扭曲,对插值放大后的多光谱图像和原始全色图像分别作相同层数的非下采样轮廓波变换分解.在相应低频子带中,分别选取以待融合像素点为中心,大小为5×5的滑动窗口,计算待融合像素点的局部相关系数与四阶相关系数.如果局部相关系数大于四阶相关系数,说明该位置上的地物存在相似的光谱特征,因此用全色图像的高频系数替代多光谱图像的高频系数;反之,保持多光谱图像的高频系数不变.最后将多光谱图像的低频系数和替换后的高频系数进行非下采样轮廓波逆变换得到融合图像.采用Landsat 7遥感图像,对比给出了本文与现有同类最新文献融合结果及其主客观评价指标.实验结果表明,本文算法在提高空间分辨率与保持光谱信息两个方面都具有较好的效果.     

基于稀疏表示的可见光遥感图像飞机检测算法

为解决当前遥感图像飞机检测方法在复杂背景下准确率低,实现旋转不变困难的问题,结合图像稀疏表示原理,提出一种基于稀疏表示的飞机检测算法.该算法首先利用飞机是刚性目标且具有明显几何外观的特点,构建飞机几何原子库;然后建立飞机轮廓几何逼近的最优化方程,在稀疏表示原理框架下,得到飞机轮廓最优的几何部件组合;最后,以星型结构的部件模型为框架,生成待检测图像的目标显著图并根据显著图定位出飞机.实验结果表明,稀疏表示方法能自适应选取飞机部件,部件数目较少且不易受光照、颜色和复杂背景的影响.与现有算法相比,本文算法准确率达90%以上,检测速度有较大的提高.     

Can contributions to B_s→l＋l-γ from the magnetic-penguin operator with real photons in the standard model be neglected？

Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l＋l- γ,（l=e,μ） in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l＋l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future.     

我国光纤传感技术发展路线图

四十多年来,我国光纤传感技术在经济发展和市场需求的牵引下快速成长。针对我国光纤传感若干典型的细分技术领域,概括性地给出了各个细分技术的发展历程、技术现状及面临的主要问题,使读者能更好地理解我国光纤传感技术发展的样貌,把握我国光纤传感技术市场需求呈指数型增长的发展趋势。     

Multiband Terahertz Photonic Band Gaps of Subwavelength Planar Fractals

Optical transmission properties of subwavelength planar fractals in terahertz （THz） frequency regime are studied by means of time-domain spectroscopy. The transmission spectra with multiple pass bands and stop bands are observed. The tunable photonic band gaps are realized by changing the angle between the principle axis of planar fractal and the polarization of THz wave. The possible application of the subwavelength optical component is discussed. We attribute the detected transmittance from subwavelength fractals to localized resonances.     

Design and Fabrication of 1.06 μm Resonant-Cavity Enhanced Reflective Modulator with GaInAs/GaAs Quantum Wells

A resonant-cavity enhanced reflective optical modulator is designed and fabricated, with three groups of three highly strained InGaAs/GaAs quantum wells in the cavity, for low voltage and high contrast ratio operation. The quantum wells are positioned in antinodes of the optical standing wave. The modulator is grown in a single growth step in an molecular beam epitaxy system, using GaAs/AlAs distributed Bragg reflectors as both the top and bottom mirrors. Results show that the reflection device has a modulation extinction of 3 dB at -4.5 V bias.     

一个无理不等式的类比

文[1]给出了如下不等式： 设a，b〉0，0〈λ≤2，则 √a/a＋λb＋√b/λa＋b≤2/√1＋λ（1）     

微波等离子体离子束刻蚀技术

自行设计研制了一台微波电子回旋共振等离子体刻蚀系统。该系统采用微波直接通过石英窗口产生右旋圆极化波，由Nd—Fe—B永磁磁钢形成高强磁场，通过共振磁场区域内的电子回旋共振效应产生均匀的高密度等离子体。利用该系统，结合光刻技术和反应离子束刻蚀技术，在以碳氢（CH）等元素为主要组成的有机聚合物（PMMA）表面制备出线宽3-4μm的光栅形图形。原子力显微镜（AFM）测试结果表明，所得图形线条清晰，侧边比较陡直。     

新型含氟α-氨基膦酸酯的合成和晶体结构

利用含氟苯基亚胺与亚磷酸酯反应,合成了新型含氟α-氨基膦酸酯,通过元素分析、红外光谱、质谱、核磁共振氢谱对其结构进行了表征.X射线单晶衍射测试结果表明:化合物为三斜晶系,空间群P1,a=1.0178(6)nm,b=1.0354(6)nm,c=2.2534(13)nm,α=77.413(10)°,β=78.340(10)°,y=77.540(10)°,V=2.233(2)nm3,Z=4,Dc=1.289 Mg·m-3,μ=O.175 mm-1,F(000)=904.0,最终偏离因子R=0.0728,wR=0.1724.