基于S3C2440的能量色散X射线荧光光谱仪

提出了基于S3C2440的能量色散X射线荧光光谱仪的设计方案,重点介绍了EDXRF光谱仪的硬件设计及Windows CE下高速AD转换器AD7676驱动程序的开发方法,并用实例验证了该方案可以满足元素定性分析的需要。     

基于荧光图像的水华微囊藻浓度检测

通过荧光光谱仪分析了水华微囊藻叶绿素a的荧光激发特性,利用图像处理技术,提出了基于藻类荧光激发效应的水华微囊藻浓度自动检测方法.利用430 nm荧光作为激发光源,得到波长为680nm的水华微囊藻荧光显微图像,利用红色滤光片去除其它入射光的影响,使图像中只包含水华微囊藻荧光特性;对得到的荧光图像进行灰度化、二值化、滤波,进行计数以及藻液浓度测量.实验证明:此方法能够很好地区分藻类和杂质,浓度测量结果精准,计算速度快,为藻类细胞浓度检测提供了一种新的便捷方法.     

基于PLS的X光谱重金属含量模型建立

随着宜昌地区工业水平的快速发展,宜昌及周边农田土壤中重金属的污染风险在日益增大.污染土壤的部分重金属元素生物毒性显著,若过量摄入可引起生理功能紊乱、营养失调.利用能量色散X荧光光谱仪采集土壤样本光谱数据,采用偏最小二乘法建立As、Gu、Pb、Cr、Zn五种重金属元素的含量模型.模型经交互验证,其预测值与实际值的相关系数均达到0.9以上,预测均方根误差较小.研究表明,所建模型的精度及相关性均比较理想,能够较准确地测量土壤中的5种元素,对于提高能量色散X荧光光谱仪的准确性有重要意义.     

由O_2(~1△)发生的红色荧光高分辨光谱

在做氧碘化学激光试验中偶然发现:当放入某种热金属丝后,出现较强的红色荧光现象。其强度比原始的O_2(~1△)二聚物荧光强2～3个数量级。用光学多通道分析器(OMA)和Bomem傅立叶变换光谱仪分别测量了这红色荧光的光谱,最高分辨率达0.1cm~(-1)。红色荧光的发射体可能是O_4~*或Cl_2_2~*的某种异构体。     

测量叶绿素a/ c 生长特征的全光纤荧光谱仪的研究

介绍一种测量海藻中叶绿素a/c生长特征的全光纤荧光谱分析仪 ,包括荧光测量、光纤传输、光纤光谱仪数据采集、频谱分析与微机信号处理的设计 ,组成全新的光 机 电一体化的在线测量分析仪器 ,并给出了测绘的叶绿素a/c的荧光谱和反映其生长过程的时间分辨的差分谱 ,为研究藻类的浓度及其群落类别 ,进而实现海洋污染状况的监测提供了有效的方法     

基于拉曼光谱CCD信号的谱峰识别技术研究

针对在线拉曼光谱信号存在荧光背景和严重谱峰重叠的情况,提出了一种从含荧光背景信号中提取有用信号并对其进行充分分离的谱峰识别方法。首先采用小波变换扣除原始信号中的荧光背景(即低频成分),然后采用免疫算法对有用信号进行分离。由于免疫算法在组分较多情况下收敛速度慢甚至不收敛,因此,又采用主成分分析(PCA)法得到累计百分比,对免疫算法中的标准信号进行加权,从而完成对重叠拉曼光谱信号正确、快速地识别,并很好的满足了在线拉曼光谱仪在工业现场谱峰识别准确快速的要求。     

低成本微型光谱仪的设计制作

本文分析了微型光谱仪的发展现状与系统结构,设计了一种基于CMOS摄像头模块的微型光谱仪。给出了该微型光谱仪的实现方案,描述了光谱仪的软件流程,利用激光二极管对光谱仪进行了校准。采用所研制的微型光谱仪对绿光LED进行了光谱测量实验,取得了较好的检测效果。该微型光谱仪具有成本低、体积小等特点,应用前景广阔。     

基于特征串匹配的X射线荧光光谱仪数据采集

针对水泥企业在异构环境下采集X射线荧光光谱仪数据的问题,提出一种基于特征串匹配的数据采集算法,在此基础上构建一个具有通用性的水泥质量管理系统,用于自动实时地采集、存储和上传样品质量数据。应用结果证明,该系统运行情况良好,适应能力较强,较大地提高了水泥企业质量管理和生产控制能力。     

用高新技术更新改造大型科学仪器

采用面向对象的程序设计原理,Ｘ荧光光谱数据和信息交换等方面的最新技术,对八十年代从日本理学公司引进的３０８０Ｘ荧光光谱仪实现了微机改造,研究开发了达到九十年代先进水平的“ＸＲＦＩＡＳ Ｘ荧光光谱集成分析系统”,并几度改进提高,现有Ｗｉｎｄｏｗｓ３．Ｘ和Ｗｉｎｄｏｗｓ９．Ｘ两种版本的软件。可在ＰＣ４８６,５８６,Ｐ－Ⅱ等机型上运行。从而淘汰了ＰＤＰ和Ｓｏｒｄ两种过时的计算机,扩充了软件功能,创新许多     

基于Linux的便携式光谱仪数据采集系统的设计

为了满足光谱仪的小型化、智能化的要求,提出了基于Linux操作系统的光谱仪数据采集系统的设计方案,可以方便后续应用研究软件的开发;该方案主要采用Intel公司的PXA270作为光谱仪的处理器,SONY公司的ILX554B高灵敏度线阵CCD作为光电探测器,设计了光谱仪的硬件采集电路,并在分析Linux设备驱动的基础上,针对光谱仪的硬件采集电路,设计了Linux操作系统下采集设备的驱动程序,实现了光谱仪的光谱数据采集功能;经过测试,该驱动能够满足Linux操作系统下应用程序的需求。     

The identification of phytoplankton pigments from absorption spectra

The absorption spectra of photosynthetic algae are characterized by a continuous envelope, which is a result of the overlapping spectra of the indivual pigments. This feature makes it difficult to estimate the contribution of each pigment to the total absorption spectra. Derivative analysis is an objective tool for isolating absorption peaks in phytoplankton. Theoretically, electrons and ions of interacting molecules can be regarded as simple harmonic oscillators in an electromagnetic field, which result in a Lorentzian shape. However, when measured by an optical spectrophotometer the signal is transformed into a Gaussian curve. Thus, a combination of both types of curve provides a realistic approach to the decomposition of absorption spectra. In this study derivative analysis is performed on absorption spectra in order to prove that the method can be successfully used to identify the individual absorption spectra of component pigments. The spectra used are modelled phytoplankton, spectrophotometric measurements of algal cultures and samples from natural waters. A combination of Gaussian-Lorentzian shaped curves, centred on the identified peaks, were compared with the original spectra and showed good agreement.     

Detecting photosynthetic algal pigments in natural populations using a high-spectral-resolution spectroradiometer

Reflectance data from a high spectral resolution spectroradiometer were obtained onboard a ship in Plymouth coastal waters. These data were analysed to detect algal photosynthetic accessory pigments for comparison with absorption spectra as measured in the laboratory by a spectrophotometer. The overall spectral characteristics of Plymouth waters allowed identification as to population composition. Derivative analysis of the spectra was used to resolve characteristic peaks of specific pigments. It was determined that chlorophyll pigments, a specific carotenoid and sea water absorption bands were detectable in the reflectance data. Absorption bands of photosynthetic and accessory pigments were assessed through chromatographic pigment analysis.     

矿物与岩石的可见-近红外光谱特性综述

矿物和岩石的系统光谱学研究是当今高光谱遥感发展的基础。在简要介绍了吸收光谱产生的电子过程和振动过程机理后,系统归纳了主要矿物类型和岩石类型的可见-近红外光谱特征。认为矿物的吸收光谱主要由二价、三价铁离子和过渡族元素的电子跃迁以及晶体场效应等电子过程产生;此外,还可以由水分子、Al-OH、Mg-OH、碳酸根的振动过程及卤化物的色心和硫化物的导带产生;岩石的吸收光谱都是杂质、包体、蚀变及替代成分产生的,主要为铁、水和羟基、碳酸根、硼酸根的光谱。最后指出,不同物理、化学环境下的矿物光谱特征变异研究在将来的高光谱遥感地质勘察中将变的更为重要。     

二维黑磷纳米片的液相剥离和稳定性研究

黑磷是一种具有天然褶皱结构的直接带隙二维半导体材料,因其拥有诸多传统二维半导体材料不具备的优秀特性,故自 2014 年起倍受研究人员的青睐。在该研究中,首先,通过液相剥离方法成功制备了不同尺寸大小的二维黑磷纳米片;其次,用扫描电子显微镜、透射电子显微镜和原子力显微 镜对样品的尺寸、形貌、厚度进行系统表征,并对不同尺寸大小的二维黑磷的拉曼散射光谱进行了研究。由于黑磷在水中会逐渐反应生成磷酸或亚磷酸,所以黑磷在水氧环境中会逐渐分解。而黑磷的可降解性是它作为可降解生物医用材料的重要基础,故对不同尺寸的黑磷纳米片的降解特性进行了一系列的检测。研究不同尺寸黑磷纳米片水溶液的吸收光谱和 pH 值随时间变化过程发现,黑磷纳米片在前 3 天会迅速降解,之后其降解速率逐渐平稳;同时发现纳米片的尺寸越小,其降解速率越快。     

Application of the fast fourier transform method for compression of spectral data obtained from a photodiode array spectrophotometer

Data compression using the Fourier transform method was applied to data generated from an ultraviolet-visible photodiode array spectrophotometer. The spectroscopic data were converted into the Fourier domain by using the fast Fourier transform technique. Four different methods were utilized to reduce the number of Fourier coefficients required for accurate reproductions of the original spectra. The performance of these methods in data compression was evaluated by using synthetic spectra as well as experimental absorption spectra. It was found that the storage space of the spectral data can be reduced by more than 90% by using three of the suggested methods.     

基于吸收光谱乙炔气体浓度在线检测系统的研究

可调谐二极管激光吸收光谱技术是利用二极管激光器的波长调谐特性,获得被选定的待测气体特征吸收谱线的吸收光谱,从而对待测气体进行定性或定量分析技术,与多次反射池相结合,利用谐波检测技术对所提取的微弱信号进行处理,设计了一套远距离在线测量乙炔气体监测系统,经过系统实验,能准确、快速地完成乙炔气体浓度的监测。     

Multiwavelength analysis for a first-order consecutive reaction

Multiwavelength data acquisition for a two-step first-order consecutive reaction was achieved in a single run experiment using a computerized UV-visible scanning spectrophotometer. Nonlinear least square fitting procedures were applied to the spectral data obtained to deduce rate constants and other parameters of the reaction. Since measurements were carried out at around absorption maxima of constituting components and more experimental quantities at different wavelengths are available, kinetics reaction parameters and concentration-time profiles can be determined with higher accuracy than those in the conventional method. The present experimental setup can be adopted for kinetics systems of which components have absorption maxima close to one another or overlapping spectra.     

一种激光诱导荧光光谱特征提取新方法

利用主成分分析（Principal Component Analysis,PCA）和Fisher线性判别分析（Fisher Linear Discriminative Analysis,FLDA）方法相结合提取特征,提出了一种荧光光谱特征提取新方法——PCA_FLDA。实验证明,新方法提高了激光诱导自体荧光光谱对早期结肠癌的诊断精度。对预处理后的240条荧光光谱,利用PCA_FLDA算法提取了50个特征变量,利用支持向量机将其分为正常组织和癌变组织,分类敏感性、特异性和准确率可分别达到97.5%、95.12%和96.25%。     

西替利嗪及其盐酸盐电子结构及CD谱的理论解析

采用量子化学密度泛函理论在B3LYP/6-31++G~(**)水平上对西替利嗪及其盐酸盐分子几何构型进行了优化;在优化的基础上进行红外光谱(IR)、振动圆二色谱(VCD)、紫外光谱(UV)和电子圆二色谱(ECD)研究。计算结果表明:盐酸盐中Cl~-与季胺N~+之间的静电吸引作用可能通过Cl…H—N氢键作用进行传递。涉及到或者靠近手性中心的振动在VCD谱上表现出强的Cotton效应;远离手性中心的振动,尽管在IR谱上出现较强的吸收,在VCD谱上也可能不产生Cotton效应。ECD谱分析发现,涉及到手性中心的电子跃迁,在ECD谱上产生Cotton效应。     

Self-consistent theory of selective reflection

A relatively simple procedure is developed for calculation of transmission and selective reflection spectra in a system consisting of a layer of atomic vapor sandwiched between two transparent solids with parallel interfaces. The proposed method allows one to correctly take into account multiple reflections, absorption, and spatial dispersion of atomic medium and is applicable to arbitrary densities and optical lengths of atomic medium. The article is published in the original.