拉曼光谱技术在石油化工领域应用进展

拉曼散射是物质一种分子光谱,可以获取物质结构和官能团信息,已经用于物质的定性分析。本文就拉曼光谱技术在石油化工行业的应用进行简述。结合化学计量学,拉曼光谱技术已经用于石油产品组成分析、燃料（汽油、柴油、航煤和生物柴油）质量指标测定、输油管线油品监控以及化工产品和石油产品在线监控等领域。拉曼光谱技术具有结果准确、分析速度快、操作简单、不破坏样品、多参数、便携以及可现场分析等优点,将在石油化工领域得到进一步推广应用。     

激光拉曼光谱的若干应用技术

目前国内在运用拉曼光谱进行光谱——结构研究方面,已作了不少工作,但分析应用方面的报导仍不多见。本文拟就拉曼光谱在分析应用方面的若干技术作些简要介绍供参考。 Sloane曾对红外光谱和拉曼光谱在样品处理、仪器结构和应用方面的差别作过详细的比较。由于拉曼散射出现在光谱的可见区,并且能对水溶液进行测量,固此拉曼光谱有着特殊的显著优点。红外与拉曼光谱     

表面增强拉曼光谱的研究进展

本文从提高表面拉曼光谱检测灵敏度和空间分辨率两个方面的发展叙述表面增强拉曼光谱和针尖增强拉曼光谱的原理、方法、特点以及最新进展。对利用表面增强拉曼光谱和针尖增强拉曼光谱研究金属表面上分子吸附等方面的应用进行总结 ,并对他们的应用前景做了预测     

关于共振拉曼精确测量的几个问题

共振拉曼的原理及其应用已有许多报导,本文对在测量中应注意的几个问题作介绍。在共振拉曼光谱中样品的吸收和噪声是精确测量共振拉曼光谱的主要障碍。在共振拉曼实验中用与样品吸收相当的激光频率来照射。彼样品吸收的能量以三种形式来影响共振拉曼光谱,使光谱减弱。(1)入射光和     

海洋光学与江苏省食品药品检验所成功举办“拉曼光谱在药检领域应用”研讨会

拉曼光谱白发现以来,经过近80年发展,做出了其他分析技术所不能做到的许多特殊贡献。近年来,拉曼光谱法在药物分析中的应用越来越多,中国药典2010版将根据这一发展,在附录中新增拉曼光谱法指导原则,以进一步促进这一方法在药品检验中的应用。为了帮助相关制药、科研、高教单位掌握拉曼光谱方法并顺利开展工作,2008年8月,     

拉曼光谱的应用及其进展

本文简述了拉曼光谱的原理、特征及其在应用上的优越性。介绍了几种新的拉曼光谱技术及拉曼光谱技术在食品、材料化学、医药等领域的最新研究及应用进展。重点讨论了近年来该技术在食品质量检测、环境保护、细胞和组织的癌变方面的最新进展,并对其应用前景进行了展望。     

拉曼光谱技术在涂料鉴定中的应用进展

本文对拉曼光谱在涂料鉴定中的研究和应用现状进行综述,简要说明拉曼光谱用于涂料鉴定的特点,并对其应用前景进行展望。     

基于高波数拉曼光谱的口腔癌检测方法研究

目前口腔癌触诊检查依赖于医生经验,术中冰冻切片的检测方式为有创检测,准确性较低,为满足临床手术对口腔癌检测的实际需求,研究了基于高波数(2 400～4 000 cm~(-1))光纤激光拉曼光谱的口腔癌检测方法。研究光纤拉曼光谱实现口腔癌检测的原理,分析了主成分-线性判别分析(PCA-LDA)统计算法的可行性,搭建了便携口腔癌组织检测光纤拉曼系统,制备了口腔癌组织和正常组织病理切片,采集了口腔癌组织和正常组织的高波数拉曼光谱,利用PCA-LDA算法对光谱进行处理和分析。光谱分析结果表明,癌组织和正常组织的平均光谱在2 780、2 890、2 936、3 180、3 285、3 300、3 650 cm~(-1)有较大区别,利用PCA-LDA分析,对正常组织和口腔癌组织拉曼光谱进行降维分类,检测准确率为96.6%,与共聚焦显微拉曼光谱检测相比,提高了检测效率,较指纹拉曼光谱检测准确率提高约0.6%,研究表明高波数拉曼光谱结合统计学方法可以较好的区分正常组织和癌组织,有望成为一种高灵敏度,高时效性和高准确率的口腔癌检测方法,对术中口腔癌检测有重要意义。     

激光拉曼光谱相似性测度方法

现代固体激光器、光谱仪技术和软件技术的进步使激光拉曼光谱快速进入实用阶段,并开始广泛地用于物质结构分析与鉴定。文章详细地阐述了拉曼光谱的基本原理,指出拉曼光谱的本质是可见/近红外光谱,重点对采用激光拉曼光谱进行物质鉴别分析时常用的三类相似性测度方法——距离测度、相似性函数和峰匹配作了深入的分析,并就各种方法的特点做了说明     

拉曼光谱在中药注射剂鉴定中的应用初探

分析了中药注射剂的重要作用,探讨了利用拉曼光谱进行中药注射剂鉴定的可行性。运用拉曼光谱检测了中药灯盏花素注射剂和红花注射剂,并对其拉曼谱图进行了分析。灯盏花素注射剂和红花注射剂的拉曼谱图中虽然荧光背景很强,但依然包含了不少有用信息,这表明利用拉曼光谱鉴定中药注射剂是可行的,但是测量技术和技巧还有待进一步提高。     

拉曼光谱测量中的荧光抑制方法综述

拉曼光谱是物质的特征结构谱,但是在许多情况下,除了激发出拉曼散射光之外,还会激发出强度远大于拉曼散射的荧光,从而限制了拉曼光谱的应用。因此在拉曼检测中对荧光采取抑制措施是十分必要的。在过去的几十年里发展了多种荧光抑制方法,包括荧光淬灭剂法、光漂白法、红外/紫外激发法、偏振调制法、移频激发法、高频调制法、门控法、数值处理法、非线性效应法等。文中概括性地介绍了上述各种技术方法的原理,并扼要地分析比较了各自的性能特点。     

QUANTIFICATION OF BINARY MIXTURES OF COCAINE AND ADULTERANTS USING DISPERSIVE RAMAN AND FT-IR SPECTROSCOPY AND PRINCIPAL COMPONENT REGRESSION

Current forensic methods for detecting and identifying cocaine and its adulterants are destructive, so evidence cannot be re-analyzed. Vibrational techniques [Raman and Fourier transform infrared (FT-IR) spectroscopy] allow rapid, economical, nondestructive analysis. This work compares these techniques as methods for quantifying mixtures of cocaine (in the crack presentation) and adulterants. The aim is to provide a method to determine the amount of cocaine in crack rocks and to identify and quantify possible adulterants. A sample of crack was adulterated with benzocaine, caffeine, sodium carbonate, and lidocaine to create binary mixtures of concentrations of 20%, 40%, 60%, and 80%; pure samples of each adulterant and of crack were also examined. All samples were observed using dispersive Raman and attenuated total reflectance FT-IR spectroscopy. Quantitative analysis was performed based on principal component regression (PCR) applied to simulated and real spectra. The PCR model revealed that the Raman spectra yielded only minor measurement errors and the highest correlations using the PC2 spectral vector, which presented spectral features of cocaine. Among the mixtures, the best and worst results were obtained for caffeine and sodium carbonate, respectively. Dispersive Raman spectroscopy outperformed FT-IR in the quantitative determination of binary mixtures of cocaine and adulterants.     

Candle Soot as Particular Lubricant Additives

An onion-like carbon material was prepared from candle soot, and its tribological properties as an additive were investigated in water. The material assumed a spherical shape with a layered nanostructure based on high-resolution transmission electron microscopic analysis and had considerable sp² hybrid carbon as revealed by Raman spectroscopy. The tribological properties were determined on an optimal SRV-IV oscillating reciprocating friction and wear tester. The results indicate that these candle soots as additives are able to effectively reduce both the friction and wear of sliding pairs in water. In addition, the chemical reactivity, physical stability, surface charge, and size of candle soot had a key impact on their lubrication properties. Based on our characterization of the wear scars by scanning electron microscopy and in situ Raman spectroscopy, we suggest a rolling and sliding lubrication mechanism.     

Invited review article: combining scanning probe microscopy with optical spectroscopy for applications in biology and materials science

This is a comprehensive review of the combination of scanning probe microscopy (SPM) with various optical spectroscopies, with a particular focus on Raman spectroscopy. Efforts to combine SPM with optical spectroscopy will be described, and the technical difficulties encountered will be examined. These efforts have so far focused mainly on the development of tip-enhanced Raman spectroscopy, a powerful technique to detect and image chemical signatures with single molecule sensitivity, which will be reviewed. Beyond tip-enhanced Raman spectroscopy and/or topography measurements, combinations of SPM with optical spectroscopy have a great potential in the characterization of structure and quantitative measurements of physical properties, such as mechanical, optical, or electrical properties, in delicate biological samples and nanomaterials. The different approaches to improve the spatial resolution, the chemical sensitivity, and the accuracy of physical properties measurements will be discussed. Applications of such combinations for the characterization of structure, defects, and physical properties in biology and materials science will be reviewed. Due to the versatility of SPM probes for the manipulation and characterization of small and/or delicate samples, this review will mainly focus on the apertureless techniques based on SPM probes.     

Polymers on graphite and gold: molecular images and substrate defects

Sub-monomolecular layers of a derivatized Phthalocyaninato-poly-siloxane (PCPS) and a Polydiacetylene (PDA) have been prepared on highly orientated pyrolytic graphite and gold by Langmuir-Blodgett and Langmuir-Schäfer techniques. Raman scattering and grazing-incidence-reflection infrared spectroscopy were used to characterize packing and molecular orientations within these films. It was found that PCPS forms similarly well ordered monolayers on both graphite and gold while PDA does not. Scanning tunnelling microscopy (STM) was performed in air using both the constant height and constant current mode. On highly orientated pyrolytic graphite substrates various defect structures based on a √3X√3 R 30° superstructure were found near localized defects and small graphite steps. They were carefully distinguished from molecular images of densely packed hydrocarbon chains. Defect rich graphite was characterized with both STM and Raman spectroscopy. Similarly, disordered and graphite-like regions were found on carbon fibres. The sensitivity of STM to surface defects in graphitic material turned out to be large compared to that of the Raman spectroscopic method. STM images of PCPS monolayers on graphite and gold exhibited parallel polymer rods, 2 nm apart from each other.     

拉曼光谱结合深度学习算法的塑料分类的研究

拉曼光谱法能识别塑料制品光谱特征峰,但操作流程繁琐且准确率有待提升,对此提出了基于一维卷积神经网络 (one-dimensional convolution neural network, 1-D CNN) 的塑料制品分类算法,首先建立以聚乙烯 (polyethylene, PE) 、聚丙烯 (polypropylene, PP) 、聚对苯二甲酸乙二醇酯 (polyethylene terephthalate, PET) 和聚苯乙烯 (polystyrene, PS) 为原材料的40种塑料包装样本数据集;然后设计1-D CNN、K近邻 (KNN) 、决策树 (DT) 和支持向量机 (SVM) 4种算法模型进行训练,并在光谱分类流程、模型准确率和鲁棒性等方面进行对比。实验结果表明,1-D CNN在不经过预处理条件下分类准确率达到98.62%,且在60 dB噪声下仍有96.42%的准确率,优于另外3种传统机器学习算法模型。该结果证实,拉曼光谱融合神经网络的多分类方法可提升塑料制品检测性能。     

Examination of the tribolayer formation of a self-lubricant W–S–C sputtered coating

A W–S–C self-lubricating coating was deposited by d.c. magnetron sputtering from carbon and tungsten disulfide targets on steel substrates. The coating showed a carbon content of 42 at% and a S/W ratio of 1.26. The film was characterized (structure, hardness, adhesion) and tribologically tested using a pin-on-disk device. The load and number of cycles were varied and the corresponding wear tracks were thoroughly investigated by several techniques. Moreover, the wear tracks were monitored with Raman spectroscopy including in-situ measurements. The W–S–C coating exhibited friction and wear decreasing with the applied load. It has been demonstrated that the running-in process is related with changes in the Raman spectra on the wear tracks.