高通量傅里叶变换成像光谱仪调制度分析

介绍了高通量傅里变换成像光谱仪的概念,分析了其中使用的改进型Mach-Zehnder干涉仪的原理,计算出其光程差以及调制度.可以看出:要得到较好的调制图形,必须满足两像面夹角和像方孔径角都是小角的条件,且两个像点之间的横向距离和纵向距离越小越好.讨论了像面与探测器平面之间的横向和纵向偏差及CCD单元尺寸等因素对光谱仪调制度的影响.通过调节各参量,三种调制度都可以达到90％以上,能够满足光谱仪应用需求.     

采用TMS320C6203的运动点目标检测系统设计

为了实现大视场运动点目标的实时检测和识别,设计了一种基于TMS320C6203为核心处理器件,FPGA为辅助控制处理器的硬件处理系统.在对点目标检测识别算法仿真实验分析的基础上,开发了实时运动点目标检测处理的软件系统.实验测试结果表明,该系统能够对信噪比不小于3 dB,帧频为10 fps的1024×1024运动点目标图像序列进行实时检测和识别,准确检测概率达到96%,满足实际工程要求.     

单边干涉图的数据处理方法研究

干涉成像光谱仪干涉图的采样方式一般有两种,即单边采样和双边采样,单边采样干涉图往往保留零光程差附近的部分“短双边”采样数据以利于数据处理.本文对空间调制干涉成像光谱仪不同干涉图采样方式下的光谱复原方法进行了研究,讨论了空间调制干涉成像光谱仪单边干涉图的切趾与相位修正,提出了更为合理和准确的方法.研究发现,合理设置短双边数据在减小仪器的原始数据量的同时,能够保证复原光谱的准确度.     

干涉多光谱图像压缩编码新技术

提出一种基于运动估计的三维小波变换和非对称零树编码的干涉多光谱图像压缩方案.该方案利用大孔径静态干涉成像光谱仪推扫成像特点,对图像进行分区域运动估计的三维小波变换.采用了一种新型非对称零树编码方法,该方法可在较少的图像间建立较长的零树,增加了系数编码时由重要结点变为不重要结点并趋于零的概率,使编码的效果更好.该方案消耗内存少,延时小,有利于卫星上的图像压缩,有效地保护了图像的光谱特性.在8倍压缩下,满足干涉多光谱图像的质量要求.     

层析型线阵推扫成象光谱技术及其仿真研究

本文设计了一种层析型线阵推扫成象光谱仪。与色散型推扫成象光谱仪或干涉型推扫成象光谱仪不同的是,它用线阵CCD代替面阵CCD,同时又具有高通量、多通道、高信噪比、结构简单、轻量等优点。其基本原理是利用光栅的多级衍射实现视场条带目标的一维空间和一维光谱组成的“空间-光谱平面”到一维投影象的Radon变换,然后由逆Radon变换重构二维数据(一维光谱和一维空间),另一维空间信息通过推扫便可得到。文章还提供了重构算法和计算机仿真试验结果,验证了算法和方案的可行性。     

冷原子荧光法测定蔬菜中痕量汞的不确定度评定

对冷原子荧光法测定蔬菜中痕量汞的不确定度进行了评定。不确定度来源主要为配制标准工作溶液引入的不确定度,称取样品质量引入的不确定度,样品消化引入的不确定度,定容体积引入的不确定度,重复测定引入的不确定度。当蔬菜中汞含量为5.2μg/kg时,测量结果的扩展不确定度为0.50μg/kg。     

小波双线性插值迭代算法应用于光学遥感图像

分析了小波双线性插值中高频外推阈值门限与重建图像峰值信噪比的变化关系,提出了峰值信噪比最大小波双线性插值迭代算法.提出的算法能够自动搜索到峰值信噪比最大的高频外推最佳阈值门限,实现了在不破坏光学遥感图像原始信息的情况下,提高图像的空间分辨率,有利于对图像的细节信息进行观察分析.实验结果表明,该算法重建图像的峰值信噪比比双线性插值和全小波插值重建图像的峰值信噪比高5.5 dB和2.5 dB,重建图像的熵增加到原图像的1.3倍.     

Dismutation of Titanium Sub-oxide into TiO and TiO2 with Structural Hierarchy Assisted by Ammonium Halides

Black TiO_2−x attracts enormous attention due to its large solar absorption and improved conductivity. In this work, a novel structure of TiO_2−x with conductive TiO layer, performing full-spectrum absorption, was synthesized in one step by the unforeseen dismutation reaction of titanium sub-oxides (Ti_nO_2n−1) in ammonium halide atmosphere. For this new reaction, a possible mechanism of decomposition-etching-disproportionation-rehydrolysis process was proposed. The vital intermediate reactant TiCl₄, which verifies the assumption, has been captured in the form of (NH₄)₂TiCl₆, especially where Ti₂O₃ is the reactant. Furthermore, this work not only can nominate TiO as an alternative for noble metals or carbon materials in the aim to improve the electron conductivity and solar absorption of black TiO_2−x, which are important in electrochemistry and optoelectronics fields, but also can be a new route to synthesize special structures for other multivalent transition metals.     

An Ultrasensitive Fluorescent Sensing Nanofilm for Organic Amines Based on Cholesterol‐Modified Perylene Bisimide

A stable, ultrasensitive, and fully reversible fluorescent sensing film for organic amines has been fabricated by assembling cholesterol (Chol)‐derived perylene bisimide on a glass plate surface. The compound exhibits excellent film formation properties and forms well‐defined nanofibers, as evidenced by SEM and AFM measurements. It has been revealed that besides the molecular structure of the specially designed perylene derivative, the existence of nanofibers in the film is another key factor to endow the film with superior sensing ability for organic amines, including aniline. The detection limit of the amine is ca. 150.0 ppt in the vapor phase and at room temperature. Furthermore, the sensing process is free of interference from common organic solvents, nitroaromatics, and particularly phenols, which makes the film a potential candidate to be used in lung cancer diagnoses and related applications.     

The magnetic phase transition in Cu-doped ZnO: From bulk to nanocluster

Using the first-principles calculations based on the density functional theory, we have investigated the magnetic properties of Cu-doped ZnO both in bulk and nanocluster. The calculated results show that the substitutional Cu ions are spin polarized and have a tendency to assemble. It is found that the ground state has shown a change from ferromagnetic phase to antiferromagnetic phase as the size for the doping system decreases from bulk to nanocluster. In bulk ZnO, the ferromagnetism is attributed to the strong hybridization between Cu 3d and O 2p states. In ZnO nanocluster, however, the antiferromagnetic exchange interaction is dominant because of the very close Cu–Cu distance.