共查询到18条相似文献,搜索用时 78 毫秒
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拉曼光谱的应用及其进展 总被引:1,自引:0,他引:1
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。 相似文献
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为了提高微量气体的拉曼散射强度,本文设计并搭建了注入锁定腔增强拉曼光谱微量气体检测平台。半导体激光器(波长为638nm,功率为15mW)输出到由三块高反镜组成的V型增强腔中,结合注入锁定技术,腔内激光强度达到7.5 W,实现了500倍的增强效果。利用该实验平台对微量单一气体及其混合气体进行了拉曼检测,并根据拉曼特征谱峰选取原则及信噪比大于3的原则,确定了H2、CO、CO2、CH4、C2H6、C2H4、C2H2的特征拉曼谱峰分别为4 156,2 143,1 388,2 918,2 955,1 344,1 975cm-1,最小检测极限分别为10.2,21.7,9.4,2.1,8.9,4.9,3.3Pa。腔增强拉曼光谱法可以实现微量同核双原子气体检测及利用单一波长激光的混合气体同时检测,具有替代气体检测传统光谱方法的潜力。 相似文献
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结合仪器的原理,从激光波长和功率、显微镜头、滤光片、共聚焦设置、光栅等几个方面简要说明了共聚焦拉曼参数条件的选取。同时简单介绍了拉曼光谱的应用。 相似文献
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Electric field polarization orientations and gradients close to near-field scanning optical microscope (NSOM) probes render nano-Raman fundamentally different from micro-Raman spectroscopy. With x -polarized light incident through an NSOM aperture, transmitted light has x, y and z components allowing nano-Raman investigators to probe a variety of polarization configurations. In addition, the strong field gradients in the near-field of a NSOM probe lead to a breakdown of the assumption of micro-Raman spectroscopy that the field is constant over molecular dimensions. Thus, for nano-Raman spectroscopy with an NSOM, selection rules allow for the detection of active modes with intensity dependent on the field gradient. These modes can have similar activity as infra-red absorption modes. The mechanism can also explain the origin and intensity of some Raman modes observed in surface enhanced Raman spectroscopy. 相似文献
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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. 相似文献
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Label‐free monitoring of inflammatory tissue conditions using a carrageenan‐induced acute inflammation rat model 下载免费PDF全文
Seung Ho Lee Sang Hwa Lee Jae‐Ho Shin Samjin Choi 《Microscopy research and technique》2018,81(6):544-550
Although the confirmation of inflammatory changes within tissues at the onset of various diseases is critical for the early detection of disease and selection of appropriate treatment, most therapies are based on complex and time‐consuming diagnostic procedures. Raman spectroscopy has the ability to provide non‐invasive, real‐time, chemical bonding analysis through the inelastic scattering of photons. In this study, we evaluate the feasibility of Raman spectroscopy as a new, easy, fast, and accurate diagnostic method to support diagnostic decisions. The molecular changes in carrageenan‐induced acute inflammation rat tissues were assessed by Raman spectroscopy. Volumes of 0 (control), 100, 150, and 200 µL of 1% carrageenan were administered to rat hind paws to control the degree of inflammation. The prominent peaks at [1,062, 1,131] cm?1 and [2,847, 2,881] cm?1 were selected as characteristic measurements corresponding to the C–C stretching vibrational modes and the symmetric and asymmetric C–H (CH2) stretching vibrational modes, respectively. Principal component analysis of the inflammatory Raman spectra enabled graphical representation of the degree of inflammation through principal component loading profiles of inflammatory tissues on a two‐dimensional plot. Therefore, Raman spectroscopy with multivariate statistical analysis represents a promising method for detecting biomolecular responses based on different types of inflammatory tissues. 相似文献
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Abstract A polycrystalline gold surface was modified with 2-benzo[c]cinnoline (BCC) in nonaqueous media using cyclic voltammetry. A multilayer BCC nanofilm at the gold surface was formed by the electrochemical reduction of 2-benzo[c]cinnoline diazonium salt (BCC-DAS). Grafting of BCC molecules onto the gold surface was verified by cyclic voltammetry using various redox probes, electrochemical impedance spectroscopy, and Raman spectroscopy. The BCC film thickness was measured by ellipsometry and calculated as 46 nm indicating a multilayer film formation. The stability and the potential range of the novel Au-BCC modified electrode were also studied in open atmosphere and pure water. The working potential range of Au-BCC electrode was found to be between ?1.8 and +1.6 V. 相似文献
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B. H. Stuart 《Tribology International》1998,31(11):687-693
This paper reviews the use of Raman spectroscopy for investigations in polymer tribology. In particular, a number of studies dealing with the problem of surface plasticisation in engineering polymers have been reported and are reviewed in this paper. Solvent and thermally-induced plasticisation have been examined using Raman spectroscopy. The polymers poly(ether ether ketone), nylon and polycarbonate have been investigated and are discussed here. 相似文献
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AbstractAn instrument combining laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy was developed for the in situ atomic and molecular composition analysis of minerals. The apparatus consists of an optical system, a sample chamber, a spectrometer for Raman and another for LIBS, as well as a control system equipped with laboratory-written software. Gypsum, calcite, prehnite, pearl, lazurite, and several mixtures of NaBr and CaCO3 were selected as samples for evaluation of the performance of the instrument. Sulfate, carbonate, silicate, and crystalline water were identified and different structures of CaCO3 were clearly distinguished by the use of a Gaussian fit. The limit of detection for CaCO3 in a NaBr mixture was 5.7?mg/g by Raman. LIBS was employed to determine calcium, magnesium, iron, sodium, aluminum, and carbon with the newly developed system. The limits of detection obtained for Ca, Na, and C were 90.2?μg/g, 84.6?μg/g, and 2.5?mg/g, respectively. The experimental results from commercial Raman spectroscopy instruments were used to verify and support the measurements from this novel instrument. 相似文献
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The structural, physical, and chemical properties of hair taken from an ovarian teratoma (teratoma hair) was first examined by atomic force microscopy (AFM), Fourier transform infrared (FT-IR), and Raman spectroscopy. The similarities and differences between the teratoma hair and scalp hair were also investigated. Teratoma hair showed a similar morphology and chemical composition to scalp hair. Teratoma hair was covered with a cuticle in the same manner as scalp hair and showed the same amide bonding modes as scalp hair according to FT-IR and Raman spectroscopy. On the other hand, teratoma hair showed different physical properties and cysteic acid bands from scalp hair: the surface was rougher and the adhesive force was lower than the scalp hair. The cystine oxides modes did not change with the position unlike scalp hair. These differences can be understood by environmental effects not by the intrinsic properties of the teratoma hair. 相似文献