几种塑料的傅里叶变换拉曼光谱分析

采用傅里叶变换拉曼光谱(FTIR)技术对几种塑料样品进行了分析,并给出了几种塑料的傅里叶变换拉曼光谱图。该方法具有快速、准确、操作简便、重复性好、不需对样品进行分离,可直接分析等特点。     

傅里叶变换拉曼光谱及其在橡胶分析中的应用

简介了傅里叶变换拉曼光谱（ＦＴ－Ｒａｍａｎ）仪的结构及特点，综述了ＦＴ－Ｒａｍａｎ在橡胶及其相关材料分析中的应用。     

傅里叶变换红外光声光谱在火炸药研究领域中的应用

阐述了傅里叶变换红外光声光谱（FTIR－PAS）的基本原理，测试条件及其在火炸药研究领域中的应用，证实了该技术在含能材料分析和研究中的实用价值。     

傅里叶变换红外光谱在橡胶研究中的应用

综述了傅里变换红外光谱在橡胶的表征、化学反应及加工使用过程中的应用情况。     

红外光谱技术的进展及其应用

对漫反射、衰减全反射傅里叶变换红外光谱和差谱等技术及其应用进行了简单介绍     

傅里叶变换衰减全反射红外光谱分析塑料的润滑剂

研究傅里叶变换衰减全反射红外光谱(ATR-FTIR)在塑料润滑剂分析中的应用。结果表明,通过ATR-FTIR法可以快速分析塑料的润滑剂。     

傅里叶红外光谱分析仪日常维护

傅里叶红外光谱分析仪凭借监测物质总类多、分析速度快、检出限相对较低、监测覆盖范围广等优点被工业园区有毒有害气体监测系统中广泛应用。本文介绍了傅里叶红外光谱分析仪原理,同时分享一些傅里叶红外光谱分析仪故障排除、日常维护知识,为傅里叶变换红外光谱法更好的服务工业园区提供参考。     

傅里叶变换红外光谱技术在法庭科学中的应用现状

傅里叶变换红外光谱技术因其方法简单快捷、结果准确直观、样品损耗小、检测成本低廉而被认为是适合分析各类物证的技术之一。通过介绍傅里叶变换红外光谱技术的原理及运用傅里叶变换红外光谱技术进行死后间隔时间推断、避孕套有关成分分析、微生物鉴定、土壤分析和车辆物证分析等几个方面阐述了其在法庭科学领域中的研究和应用现状,希望能够为该技术在法庭科学中的应用提供参考,并为鉴定相关案件中的物证提供一种新的思路。     

珍珠表层组成及结构的表征方法研究

扫描电子显微镜(SEM)、傅里叶变换红外光谱技术(FT-IR)等是表征物质组成及结构的常用方法。综述了近十几年来分析珍珠表层组成结构的表征方法,介绍了傅里叶变换红外光谱技术、X射线衍射技术、扫描电子显微镜等多种测试手段在珍珠表层官能团、晶型、形貌等结构分析中的应用,展望了表征方法的研究发展方向。     

基于Matlab的非平稳谐波检测方法仿真研究

针对传统的傅里叶变换对于检测非平稳谐波存在的缺陷,分析了两种非平稳谐波检测方法：短时傅里叶变换和小波变换。首先介绍了短时傅里叶变换和小波变换谐波检测方法的基本原理,然后通过Matlab使用上述两种方法对非平稳谐波模型进行了仿真。理论分析和仿真结果表明,两种方法均可以达到检测非平稳谐波的目的,但又各有优缺点。     

Discrimination of various poly(propylene) copolymers and prediction of their ethylene content by near‐infrared and Raman spectroscopy in combination with chemometric methods

Near‐infrared (NIR) diffuse reflectance (DR) spectra and Fourier‐transform (FT) Raman spectra were measured for 12 kinds of block and random poly(propylene) (PP) copolymers with different ethylene content in pellets and powder states to propose calibration models that predict the ethylene content in PP and to deepen the understanding of the NIR and Raman spectra of PP. Band assignments were proposed based calculation of the second derivatives of the original spectra, analysis of loadings and regression coefficient plots of principal component analysis (PCA) and principal component regression (PCR) (predicting the ethylene content) models, and comparison of the NIR and Raman spectra of PP with those of linear low‐density polyethylene (LLDPE) with short branches. PCR and partial least squares (PLS) regression were applied to the second derivatives of the NIR spectra and the NIR spectra after multiplicative scatter correction (MSC) to develop the calibration models. After MSC treatment, the original spectra yield slightly better results for the standard error of prediction (SEP) than the second derivatives. A plot of regression coefficients for the PCR model shows peaks due to the CH₂ groups pointing upwards and those arising from the CH₃ groups pointing downwards, clearly separating the bands due to CH₃ and CH₂ groups. For the Raman data, MSC and normalization were applied to the original spectra, and then PCR and PLS regression were carried out to build the models. The PLS regression for the normalized spectra yields the best results for the correlation coefficient and the SEP. Raman bands at 1438, 1296, and 1164 cm^?1 play key roles in the prediction of the ethylene content in PP. The NIR chemometric evaluation of the data gave better results than those derived from the Raman spectra and chemometric analysis. Possible reasons for this observation are discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 616–625, 2003     

Applications of laser Raman microprobe spectroscopy to the characterization of coals and cokes

Optical microscopy is widely used in the characterization of coals and cokes. This Paper shows that the laser Raman microprobe (MOLE) which combines an optical microscope and a Raman spectrometer can provide useful additional information. Three main areas were investigated: identification of minerals in coal and coke; structural characterization of coals and cokes; and the interaction of inorganic additives and coal. Where possible, the results were compared with conventional optical microscopy measurements whereby it was shown that the optical texture and Raman spectra of cokes are not closely related. The Raman spectra of high temperature cokes were used to estimate the size of microcrystalline regions.     

Raman spectroscopic study of CdS,PVA composite films

A new material, which can be used in solar energy utilization, is obtained here by adding different weights of poly(vinyl alcohol) (PVA) to the semiconducting material CdS. The effect of this addition was studied by using FT‐Raman spectrometer (based on 1500 mW Nd : YAG laser at 1064 nm), UV–Vis‐IR (190–800 nm) spectrophotometer, and X‐ray diffractometer. Our experimental results indicated the appearance of several new Raman bands, which have not existed in both CdS and PVA. Some of the bands which are already existing in the Raman spectra of PVA showed an unexpected systematic increase in their intensities after the addition of CdS to the matrix. On the other hand, some of the new Raman bands appeared in special concentrations of PVA only, whereas some of the Raman bands of CdS were found to disappear after adding PVA. Finally, shifts in some bands associated with random increase in their intensities after adding PVA to CdS was detected in the FT‐Raman analysis. The experimental evidence given here might be attributed to the occurrence of new bonds, indicating that the produced mixture is a new material. The assignment of the new bands as well as an interpretation of the obtained variations is given here. Our X‐ray diffraction data confirmed the interpretation introduced here. Moreover, the UV–Vis spectra confirmed the existence of new absorption bands in the Visible region. The I‐V characteristic curve was measured for a selected concentration of the new composite material, showing a remarkable increase in the values of the conduction current of about two orders of magnitude as compared with the pure PVA material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1984–1992, 2004     

采用Raman光谱研究硅烷接枝LLDPE的结晶结构

采用傅里叶变换红外光谱(FTIR)和Raman光谱表征了硅烷接枝线型低密度聚乙烯(LLDPE)的结晶结构。用FTIR和Raman光谱上硅烷特征峰与LLDPE亚甲基峰的强度比,可相对比较硅烷接枝LLDPE的接枝率,随着硅烷用量的增加,由FTIR计算的吸光比从0.96增至2.62,由Raman光谱计算的强度比从11.53增至14．00,两者的变化趋势相同。Raman光谱分析还表明,随着硅烷用量的增加,硅烷接枝聚乙烯的结晶相质量分数由57．58％降至46．99％,非晶相质量分数由11．58％升至16．52％,中间相质量分数从30．84％升至36．48％。     

Raman spectroscopic characterization of graphites: A re-evaluation of spectra/ structure correlation

First-order Raman scattering from nuclear grade graphites, highly oriented pyrolytic graphite (HOPG) and grafoil are reported. Spectral parameters such as band positions and bandwidths and their correlations with domain size values are presented. The dependence between the intensity ratio of the Raman D and G bands and the domain size L_a show inversely proportional behavior. However, the slope of the line fitted to the experimental points is different from previously reported results.     

Quantitative characterization of polyaniline films using Raman spectroscopy: II. Effects of self-doping in sulfonated polyaniline

Partially sulfonated polyaniline (SPANI) prepared by electropolymerization was studied using Raman spectroscopy (RS). The sulfonated substituent is known to induce a self-doping phenomenon, which allows conduction in SPANI in a larger pH range than in PANI. RS allows, to describe and discuss the modifications related to self-doping. It is shown that the charges organization (polaron lattice or bipolaron) on the chain is modified. Self-doping has an effect upon the rings nature, which presents a more oxidized character. The main SPANI characteristics: mean conductivity and high effect of protection against corrosion are explained, thanks to Raman results.     

Characterization of substituted polyaniline films using Raman spectroscopy: III. Study of a methoxylated polymer: POMA

The electropolymerization of o-anisidine leads to the formation of a polymer which is in the same time strongly oxidized and charged in a large potential range: the poly-o-methoxyaniline (POMA). The POMA Raman features are strongly different from the polyaniline (PANI) ones; in particular a new band, absent from the PANI spectrum, prevails in a large potential range. The nature of the polymer structures obtained in function of the polarization potential is discussed from their Raman spectra. A new polymeric configuration of the oxidized/charged rings is therefore described.     

NMR and FT Raman characterisation of regioselectively sulfated chitosan regarding the distribution of sulfate groups and the degree of substitution

Chitosan sulfates (CHS) were prepared with chlorosulfonic acid homogeneously and non-homogeneously. The total degrees of substitution (DS) ascribed to sulfate groups (DS_S) were determined with elemental analysis and the partial DS at 6-O-position was estimated via ¹³C NMR. CHS with diverse total DS_S and sulfation patterns were obtained according to the analysis. The effects of selected reaction parameters that can influence the distribution of sulfate groups were examined. The structure of CHS was then characterized with various NMR techniques, i.e. one- (1D-) and two-dimensional (2D-) NMR, and FT Raman spectroscopy. It was found that the primary hydroxyl groups were always predominantly sulfated for CHS prepared under homogeneous or non-homogeneous conditions and no sulfate groups at 2-N-position could be detected. Finally, the feasibility of using FT Raman spectroscopy as another alternative for determining the total DS_S of CHS was presented.     

Raman Scattering Characterization of Polytype in Silicon Carbide Ceramics: Comparison with X-ray Diffraction

Raman scattering measurements have been made on SiC ceramics prepared from two powdered by sintering at different temperatures. The Raman spectra of starting powders have also been measured. The volume contents of the 4H and 15R polytype phases relative to that of the 6H phase in the ceramics are inferred from the Raman intensity of folded modes of the acoustic branches and compared with those determined from X-ray diffraction (XRD) analysis. A strong correlation is found between the results obtained from the two analyses. The 4H polytype contents estimated by Raman measurement for specimens prepared from one powder show a good agreement with those obtained by the XRD analysis. For the 15R polytype component there is a correlation between the contents inferred by the two techniques when the content is not very small. The results obtained by the two techniques demonstrate that the Raman spectroscopy as well as the XRD analysis is useful to study the natures and preparation conditions of SiC ceramics.     

Pressure‐dependent Raman modes near the cubic‐tetragonal transition in strontium titanate

The pressure dependence of the Raman frequency shifts of various Raman modes is calculated at room temperature using the volume data from the literature for the cubic‐tetragonal transition in SrTiO₃. The isothermal mode Grüneisen parameters of those Raman modes are obtained, which decrease with increasing pressure for this molecular crystal. Calculated Raman frequencies are then used to predict the damping constant and the inverse relaxation time of those Raman modes as a function of pressure by means of the pseudospin‐phonon (PS) coupled model and the energy fluctuation (EF) model to describe the cubic‐tetragonal transition in SrTiO₃. Also, the values of the activation energy are extracted for the Raman modes studied using both models (PS and EF). Our predicted damping constant and the inverse relaxation time for the Raman modes, can be compared with the experimental measurements close to the cubic‐tetragonal transition in SrTiO₃.