Raman Spectroscopic Study of Silicon Nanopowders

Vibrational properties of silicon nanopowders are discussed with reference to Raman spectroscopic measurements. The powders were produced in a low pressure rf plasma from the cluster induced agglomeration of positive ions formed during the dissociation of silane. Influence of thermal treatment and the crystallization phenomena of the powder were studied. Raman spectroscopic measurements reveal size quantization effects for the particles as well as the existence of partially ordered regions in the apparently amorphous primary particles. The crystalline and amorphous volume fraction in the material were calculated from the relative spectraI intensities. The results obtained in these experiments are consistent with the observations from recent high resolution transmission electron microscopy studies of these powders

IN-SITU TIME-RESOLVED RAMAN SPECTROSCOPIC STUDIES OF SILVER ELECTRODE IN NaSCN SOLUTION

In-situ time-resolved Raman spectroscopy(TRRS)has been applied on studies of electrochemical adsorption of thiocyanate at silver electrode during potential cycles and potential step.It is shown that some dynamic information about the adsorption and desorption processes can be obtained.

CALORIMETRIC AND RAMAN SPECTROSCOPIC STUDIES ON THE INTERACTION OF LANTHANOID IONS WITH DIPALMITOYLPHOSPHATIDYLCHOLINE BILAYER

The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the gel to liquid crystalline transition temperature of phospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs.

Raman spectroscopic study on Hela cells irradiated by X rays of different doses

Raman spectra are used for studying the structure and protein, nucleic acid, lipid, and carbohydrate contents, while cervical cancer cells irradiated by X rays of different doses are cultivated for 24 h. After irradiation by X rays, the following results are obtained. （1） Some 12-Gy groups move to the 1237-cm^-1 band in compared with the control group＇s 1240-cm^-1 band; after irradiation by 6-Gy X ray, the 1662-cm^-1 band of amide I has a blue shift of 10 cm^-1. The above two parts show that because of X ray irradiation, some proteins＇ random coil structures have transformed into β folding. （2） The 759-cm^-1 band disappear in the 6-Gy group; the 570-cm^-1 band of every group has a red shift, but the changes in intensity are different; the 1335-cm^-1 band in every group has a blue shift, and all their intensities increase. These show that although the 570-, 759-, and 1335-cm^-1 bands all belong to the tryptophan residue indole ring vibration, the molecular vibration energy structures which produce scattering lights are different. （3） The 786-cm^-1 band only has a blue shift of 3 cm^-1 in the 6-Gy group, and the non-hydrogen band of the phosphoric acid diester （O-P-O） increases. The frequency deviation of the 1089-cm^-1 band is erratic, and the bent symmetry stretch vibration conformation of phosphoric acid diester key （O=P=O） in the nucleic acid is complex. （4） The 1570-cm^-1 band has a blue shift, and its intensities all decrease, while the C=C conjugated duplet bond oxidizes, and the content of C=C decreases.

Raman spectroscopic detection using a two-dimensional echelle spectrometer

In order to meet the high-resolution and wide spectrum range of the backscattering Raman system, this paper designs and builds a Raman test system based on the echelle spectrometer. In the optical splitting system, compared with the ordinary planar grating spectrometer, the use of the echelle improves the resolution of the system without increasing the volume of the system. The use of intensified charge-coupled device(ICCD) in the detection system improves the signal-to-noise ratio(SNR) and the detection limit of weak spectrum. Finally, the Raman system was spectrally calibrated. The broadband backscattering Raman experimental results are given and discussed. The experimental results show that the system has an excellent application prospect for broadband and high-resolution Raman spectrum measurement.

Sample maturation calculated using Raman spectroscopic parameters for solid organics: Methodology and geological applications

The shape and shift of Raman peak of solid organics prove to be capable of revealing atomic and molecular level vibration information of aromatic ring structure and its relationship with sample maturation. Raman "D" peaks and "G" peaks of a series of continuously maturated coal samples were measured, and the inter-peak intervals (G-D) and peak height ratios (Dh/Gh) were derived and correlated with the vitrinite reflectance (vRo%) of standard coal samples. As a result, two formulae were established by using the two Raman indices for calculation of Raman reflectance (RmcRo%), which is equivalent to vitrinite reflectance. The formula for calculating Raman reflectance indicative of organic maturation using Raman shift inter-peak interval (G-D) is RmcRo%=0.0537d(G-D)-11.21, which is mainly applicable to matured to highly matured carbonized samples of solid organics; The formula for calculating Raman reflectance indicative of organic maturation using Raman peak height ratio (Dh/Gh) is RmcRo%=1.1659h (Dh/Gh)+2.7588, which is mainly applicable to carbonized samples of solid organics that are over matured or going to be turned into granulated graphite. Preliminary applications indicate that Raman reflectance "RmcRo%" calculated based on results of Raman spectral analysis of solid organics can be used to characterize sample maturation at molecular level, so enjoying extensive prospects in geological applications.

Tunable filter Raman spectroscopy of purified semiconducting and metallic carbon nanotubes

Tunable filter Raman spectroscopy is used to efficiently produce Raman excitation maps of unpurified and type-purified single walled carbon nanotubes (SWCNTs). Maps with fine excitation resolution (1 nm) are created over a wide wavelength range (727 to 980 nm), extending from metallic to semiconducting resonances. At a given wavelength, the wide bandwidth (>3,000 cm–1) allows the comparison of the G band with the radial breathing mode (RBM), and shows the 2D band and other less prominent bands. Materials examined included unsorted powders, aqueous sorted semiconductors, aqueous sorted metals, and polyfluorene sorted semiconductors in toluene. The Raman excitation profiles of the G band are broad, relative to the RBM bands. The maps offer evidence of minority species contamination, except in the case of the polyfluorene sorted semiconductors. Tunable Raman spectroscopy data help validate the simpler fixed wavelength Raman spectroscopy approaches to purity assessment. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Raman spectroscopic characteristics of microcosmic and photosensitive damage on space structure of liposomes sensitized by hypocrellin and its derivatives

Raman spectroscopic characteristics of microcosmic and photosensitive damage on space structure of DPPC liposomes sensitized by hypocrellin and its derivatives are obvious. The trans conformation decreased and the gauche conformation increased. The longitudinal order_parameter in chains and the lateral order_parameter between chains decreased in different degrees. The lateral packing became loose. Photodamage on the liposomes sensitized by 5 Br hypocrellin B was stronger than that by hypocrellins A and B.

Raman spectroscopic study of space structure of membrane proteins and membrane lipids in photodamaged human erythrocyte sensitized by hypocrellin B

Laser Raman spectroscopy was used to investigate the photodamage characteristics of human erythrocyte membranes sensitized by hypocrellin B (HB) at the molecular level. It brought to light that the essence of the changes of erythrocyte membranes’ functions caused by membrane protein cross linking and membrane lipid peroxidation, including increase of fluidity and ion permeability of membranes, etc., was that the orderly structure of erythrocyte membranes had been damaged by the active oxygen ( 1O 2, O 2 .- and .OH) generated by HB, including the decrease of α helix, β sheet and the increase of random coil in the main chain of membrane proteins, the decrease of mercapto groups, indole rings, p hydroxy phenyl rings, monosubstituted phenyl rings, etc. in the side chain, and the changes of the conformations of membrane lipids as well. With the increase of the irradiation time, the trans conformation of membrane lipids increased first, then decreased. On the contrary, the gauche conformation decreased first, then increased. In addition, the decrease of the intensities of the lines assigned to bending vibration of the conformation insensitive CH 2 and CH 3 of membrane proteins and lipids suggested that break of their chains had occurred.

Raman and Infrared Spectroscopic Investigation of Some Hydrous LnTPPTS Complexes(Ln=La,Sm)

The Raman and IR spectra of LnTPPTS·10H 2O[Ln=La,Sm,TPPTS=P(m C 6H 4SO 3)3-3]complexes are reported.Based on the observed Raman and IR characteristic frequencies,a vibrational assignments has been made for these complexes.Coordination induces a lengthening of the S—O bonds and a shortening of the C—S bond.The C—S stretching frequencies should therefore increase while the position of the v(SO 3)should move to a lower wavenumber.Vibrational modes of metal oxygen polyhedronν(Ln—Ο)at 146,168,253 cm-1 are the structural charactrization for coordinate bond of LnTPPTS complexes.

基于拉曼光谱技术的聚合物材料制备与组成分布的研究进展

聚合物材料制备过程和聚合物中添加剂的含量及分布决定了材料的性能,拉曼光谱技术为相关研究提供了一种有效的表征手段。基于拉曼光谱的基本原理,介绍了表面增强拉曼光谱、拉曼光谱成像、激光显微共聚焦拉曼光谱等多种拉曼光谱衍生技术,总结了相关技术在聚合物加工和聚合反应过程中的应用,评述了聚合物中添加剂分布的检测,涵盖了乳化剂、染料以及其他添加剂的浓度、分布及迁移规律等,并对拉曼光谱衍生技术进行了展望。

论川东北地区发现的高密度甲烷包裹体类型与油裂解气和页岩气勘探评价

据甲烷包裹体的产出特征和显微激光拉曼分析研究,近年来在川东北地区先后发现了多种类型的高密度甲烷包裹体,揭示了油气藏和石油包裹体的高温热演化作用的重要信息:普光气田三叠系碳酸盐和碎屑岩储层中含焦沥青的高密度甲烷包裹体分别反映了早期油藏阶段矿物捕获的石油包裹体经后期高温极端裂解的成因;普光5井碳酸盐储层中含H2S而不含焦沥青的高密度甲烷包裹体,反映了古油藏高温裂解阶段新生方解石捕获了储层中富含CH4也有"TSR"成因的H2S流体的信息;五科一井下志留统黑色硅质岩石英中发现的高密度甲烷包裹体和少量含轻烃包裹体,反映了本区富有机质的下志留统高演化程度的黑色页岩在地质历史中存在高压甲烷和轻烃产出的证据。以上各种高密度甲烷包裹体成因机理和形成的高温度高压力条件,为川东北地区古油藏裂解气和志留系"页岩气"的勘探评价提供了科学依据。

云南前寒武系—寒武系界线锆石激光拉曼光谱研究及意义

本文通过对8个澳大利亚TEM标准锆石和近百枚云南梅树村剖面前寒武系—寒武系界线M5层斑脱岩火山成因锆石进行了不同入射方位的激光拉曼光谱分析和对比研究。证实正常锆石拉曼光谱各峰的出现、强度与拉曼光束的入射方位有关,同时也发现晶化度差的异常锆石其拉曼光谱各峰的出现、强度与拉曼光束的入射方位无关或有很小的关系。这类异常锆石在四个不同方位上并不产生特征拉曼谱峰,就是有其强度也非常小。可以认为这些异常锆石的激光拉曼光谱特征与其晶体结构及蜕晶化的程度是有密切关系的。笔者等发现:①产在新鲜的火山灰M5层中约有80%的锆石因为高铀钍含量已发生不同程度蜕晶化,5%的锆石为滚圆状的继承老锆石,均为不适合铀-铅离子探针质谱(SHRIMP)和热电离同位素质谱(ID-TIMS)定年的异常锆石;②因为低铀钍含量该M5层中仅有15%的锆石没有发生蜕晶化,为适合SHRIMP和ID-TIMS同位素定年的正常锆石,只有这类锆石的年龄才能代表前寒武系—寒武系界线的年龄。首次提出火山成因锆石晶化度与锆石拉曼光谱的定量关系。使用这项显微拉曼光谱新技术方法可以对寒武系底界M5层火山灰或其它火成岩和变质岩锆石晶体的晶化状况作出了快速判断。对U-Pb定年来讲是一种简单易行并且十分有效的重要制约手段。

阳离子对硅酸盐玻璃激光拉曼光谱影响的研究

运用拉曼光谱技术研究了Na2O(K2O)—CaO(MgO)—SiO2,Na2O(K2O)—Al2O3—SiO2,Na2O(K2O)—B2O3—SiO2,Na2O(K2O)—PbO—SiO2和PbO—BaO—SiO2五个系统的玻璃。结果表明,阳离子对玻璃近程结构的改造会引起拉曼特征的变化。部分样品是根据古玻璃平均成分在实验室烧制的,这项研究对于运用激光拉曼光谱区分不同系统的古代硅酸盐玻璃有重要意义。

拉曼光谱的发展及应用

本文阐述了拉曼光谱产生的基本原理;介绍了拉曼光谱的发现、发展过程;讨论了表面增强拉曼光谱技术、高温拉曼光谱技术、共振拉曼光谱技术、共焦显微拉曼光谱技术和近年来在不同领域的应用及研究新进展。

拉曼光谱技术在中国古玉、古玉器鉴定和研究中的应用

激光拉曼光谱技术是应用于科技考古研究中的高技术之一,属于无损分析研究,但作为一种很好的无损分析方法它在中国古代玉器研究中的应用并不非常广泛。文章首先介绍了激光拉曼光谱技术的基本原理及近几年来国内外的最新进展,然后从矿物结构与拉曼特征峰之间的关系入手比较了目前国内外5种常见玉石的激光拉曼研究结果。然后分别通过对浙江良渚遗址和河南安阳殷墟遗址出土的4件中国古代玉器与新疆和田地区出产的软玉样品进行对比研究,成功地利用激光拉曼光谱技术对一批中国古代玉器进行了无损鉴定,从而阐明该项技术在中国古代玉器结构测试和材质鉴定中是一种很好的无损分析研究方法。最后,讨论了目前激光拉曼光谱技术在中国古玉和古代玉器研究中存在的局限性并对其发展前景进行了展望。

微型拉曼电解池现场研究硫酰氯的电化学还原

硫酰氯作为液体阴极活性材料,具有比能量高、毒性低和可循环性等显著优点。由于其放电性能受炭电极材料和结构的影响,过去的一些研究主要在于探讨适宜的炭电极材料和制备技术。我们研究了硫酰氯大功率放电特性,充放电性能,认为在了解硫酰氯电化学还原的基础上,寻求合适的催化方式以发挥该体系的固有优势,可以使其成为最有竞争力的新型大功率锂电池体系。硫酰氯还原过程中涉及到多种硫氧卤素互化物。

基于拉曼光谱分析的热处理松木吸湿机理研究

木材热处理可以显著降低木材的吸湿性,是提高其尺寸稳定性的有效改性方法。以南方松热处理材和对照材为试材进行动态水蒸气吸附试验,并借助拉曼光谱对两种试材的化学组分进行比较,探索热处理对木材吸湿性能的改性机理。结果表明:在本试验条件下,热处理不仅降低了木材的吸湿量,也改变了其吸湿特性,表现为热处理材平衡含水率变化率的降低和吸湿滞后性的增强。在实际应用中,这表明热处理材即使在环境湿度变化较大的情况下也能保持较好的尺寸稳定性。拉曼光谱分析表明,木素的结构变化是热处理材形成其吸湿特性的主要内在原因之一。热处理后木素在细胞壁中的相对含量有所上升,结构发生了重组,使木材细胞壁结构变得更加稳固而缺乏弹性,对木材的吸湿和平衡起到了阻滞作用。

拉曼光谱的应用及进展

本文介绍了拉曼光谱与红外光谱的应用区别,重点综述了拉曼光谱在高温、高压、共振、表面增强技术上的应用,以及拉曼光谱的快速分析检测,提出了拉曼光谱技术存在的主要问题与发展前景。

沉积参数对Mo-Re合金基体上沉积金刚石薄膜的影响

采用热丝化学气相沉积法(HFCVD),以甲烷和氢气为反应气体,在综合性能良好的Mo-40%Re(摩尔分数)合金基体上沉积金刚石薄膜。采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)和显微激光拉曼光谱仪(Raman)分别对金刚石薄膜相组成、表面形貌、晶粒大小和质量等进行检测分析,研究CVD沉积参数,如基体温度(θs)、碳源浓度(R,CH4的体积分数)和沉积压强(p),对金刚石形核、生长和金刚石成膜的影响。结果表明:在合适的基体预处理条件下,当θs=750℃,R=3%,p=3.5 kPa时,薄膜平均线生长速率高达1μm/h,得到的金刚石膜完整致密,晶粒大小均匀,纯度较高,具有明显的(111)织构。