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H. Kinoshita N. Miyoshi Y. Fukunaga T. Ogawa T. Ogasawara K. Sano 《Journal of Raman spectroscopy : JRS》2008,39(5):655-660
We employed Raman microspectroscopy to measure the Raman spectra of phosphate in sound and carious tooth substance. The peak intensity at 960 cm−1 of the phosphate (PO43−) symmetric stretching vibrational mode (υ1) in sound enamel was stronger than that of sound dentin, which indicated that sound enamel contained more phosphate than sound dentin. Furthermore, the element analysis of phosphate in sound teeth substance, measured using a scanning electron microscope (SEM) equipped with an energy dispersive X‐ray spectroscope (EDX), gave similar results to those of the Raman measurement. In addition, the border between sound enamel and dentin was clearly demonstrated by mapping the image of the Raman spectrum of phosphate. The mapping image of phosphate in the carious enamel region revealed a heterogeneous low Raman spectrum intensity of phosphate in the area surrounding carious enamel; this finding indicates that phosphate had dissolved from the tooth substance in such areas. In contrast with the decrease in the Raman spectrum intensity of phosphate, the intensity of amide I increased mainly in the low‐phosphate area. Although it remains very difficult to clinically identify the accurate border between sound and carious tooth substance, this distinction may be enabled by using the Raman spectrum of carious tooth substance. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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海水水下温度测量对研究海洋环境和气候监测及自然灾害的早期预报等十分重要。利用蓝绿激光在海水中良好的透射性,拉曼光谱技术可应用于大面积海水水下温度的快速遥感监测。但目前能够实现现场连续水温监测功能的实用化拉曼光谱水温遥测系统还尚未见报道。研制了实用化低成本的拉曼光谱水下温度遥测系统,开发了光谱实时采集和数据处理软件。数据处理中结合了面阵CCD的空间累加与时间积分及本底扣除算法,有效增强了拉曼光谱的信噪比和光谱系统的探测灵敏度。为了提高实际测温精度,以短波段拉曼谱的面积(SHB)与长波段拉曼谱的面积(SNHB)之比作为光谱信标与水温建立关系,研究了测温精度与光谱积分范围和拟合阶次的关系。实验测量了五百多组不同水温的拉曼光谱,分别选用比值SHB/SNHB和SNHB/SHB与水温进行线性拟合和二阶多项式拟合。研究结果显示,分界波长对面积比值变化范围影响很大,而拟合阶次对面积比与温度的拟合关系的准确度影响很大,两者最终都影响水温测量误差。为了更客观地反应不同面积比法、分界波长和拟合阶次对水温测量误差的影响,分析了温度测量误差与不同分界波长的关系。结果显示,温度测量误差受分界波长影响较小,受面积比法和拟合阶次影响较大;相同情况下2阶多项式拟合结果优于相应的线性拟合结果;而采用比值SHB/SNHB与水温进行线性拟合时测温精度较高,且拟合参数易于调整。进一步研究了不同面积比方法和分界波长对系统抗干扰性能的影响。研究结果显示,比值SHB/SNHB法抗干扰能力随分界波长减小而减小,而比值SNHB/SHB法抗干扰能力随分界波长减小而增大。上述研究结果提高了温度反演算法参数设置的合理性和拉曼散射系统测温精度及系统抗干扰能力。综合考虑上述研究结果,数据处理中设定649.3 nm作为分界波长计算拉曼光谱面积比SHB/SNHB与水温进行线性拟合。最后通过实验检验了拉曼光谱水下温度遥测系统的连续实时测温能力和测温精度。结果显示,拉曼光谱系统测温值与高精度同步温度传感器测量温度一致,最大测温误差为±0.5 ℃,测温误差的标准差约0.21 ℃。 相似文献
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PAN基碳纤维在石墨化过程中的拉曼光谱 总被引:5,自引:1,他引:4
采用激光拉曼光谱研究了PAN基碳纤维在石墨化(2 000~3 000 ℃)过程中的结构变化;比较了石墨化前后纤维表面和断面拉曼光谱特征。结果表明:高温石墨化后,碳纤维的一级拉曼光谱有3个峰(D,G和D′),表征碳纤维结构有序程度的拉曼参数主要有D和G峰的半高宽(FWHM)、G峰的拉曼位移和D与G峰的积分强度比R(ID/IG)。随着热处理温度的提高,D和G峰的半高宽、G峰的拉曼位移和R值均逐渐减小,即使经过3 000 ℃高温处理后,D峰仍然存在,R值为0.19,说明纤维中仍存在无序结构。另外,R值与纤维中石墨微晶的基面宽度La成反比,石墨化后纤维取向性的增加使得表面和断面的拉曼光谱有明显的差异。因此,可利用激光拉曼光谱来定量表征碳纤维的石墨化程度和取向。 相似文献
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The experimental Raman spectra of graphene exhibit a few intense two-phonon bands, whichare enhanced through double-resonant scattering processes. Though there are manytheoretical papers on this topic, none of them predicts the spectra within a single model.Here, we present results for the two-phonon Raman spectra of graphene calculated by meansof the quantum-mechanical perturbation theory. The electronic and phonon dispersions,electronic lifetime, electron-photon and electron-phonon matrix elements, are all obtainedwithin a density-functional-theory-based non-orthogonal tight-binding model. We studysystematically the overtone and combination two-phonon Raman bands, and, in particular,the energy and polarization dependence of their Raman shift and intensity. We find thatthe ratio of the integrated intensities for parallel and cross polarized light for alltwo-phonon bands is between 0.33 and 0.42. Our results are in good agreement with theavailable experimental data. 相似文献
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光学声子色散关系对多孔硅喇曼谱的影响 总被引:2,自引:0,他引:2
测量了多孔硅的喇曼光谱,观察到谱峰有明显的红移和非对称性展宽效应。用微晶模型对此现象进行了解释:认为谱峰的这种变化不完全是由尺寸的空间限制效应和多孔硅的应变造成的,更主要的是多孔硅的色散关系发生了变化。采用不同的色散关系对谱峰进行了拟合,发现色散关系对喇曼谱的拟合有较大的影响。 相似文献
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High-sensitive automatic transient laser-induced breakdown spectroscopy system with high temporal and spatial resolution
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A high-sensitive automatic transient laser-induced breakdown spectroscopy (LIBS) system is designed and integrated. It successfully avoids the delay time selecting problem in conventional LIBS system, and realizes the LIBS data acquisition with high spatiotemporal resolution automatically. Multiple transient spectra can be obtained in each measurement, which will provide more information for spectral research. The water-vapour and liquid-water Raman scattering spectra are captured by this system, and the comparison of experimental water-vapour Raman scattering spectrum with theoretical data verifies the reliability of the LIBS system. Based on this system, the air laser induced air breakdown spectra are captured and analysed. The system is also useful for the research on water-vapour Raman Lidar remote sensing. 相似文献
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A highly-sensitive automatic transient laser-induced breakdown spectroscopy system with high temporal and spatial resolution
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A highly-sensitive automatic transient laser-induced breakdown spectroscopy(LIBS) system is designed and integrated.It successfully avoids the delay time selecting problem in the conventional LIBS system,and realizes the LIBS data acquisition with high spatiotemporal resolution automatically.Multiple transient spectra can be obtained in each measurement,which will provide more information for spectral research.The water-vapour and liquid-water Raman scattering spectra are captured by this system,and the comparison of experimental water-vapour Raman scattering spectrum with theoretical data verifies the reliability of the LIBS system.Based on this system,the air laser induced air breakdown spectra are captured and analysed.The system is also useful for the research on water-vapour Raman Lidar remote sensing. 相似文献
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共焦显微拉曼光谱技术在墨迹鉴定方面的应用 总被引:3,自引:0,他引:3
利用共焦显微拉曼光谱技术,用可见514.5nm和紫外325nm激光器作激发光源,分别测试了不同品牌的黑色圆珠笔,蓝色圆珠笔和黑色签字笔墨迹的拉曼谱图。在可见514.5nm激光器的激发下,黑色和蓝色圆珠笔墨迹都呈现了丰富的拉曼特征峰而黑色签字笔仅出现了碳峰的信号;此时改换325nm激光器来激发,发现黑色签字笔墨迹出现了清晰的拉曼特征谱峰。通过实验数据对比发现:同一类型且不同品牌笔的墨迹拉曼特征谱峰也存在一定的差异,同一种品牌墨迹的拉曼峰都保持了相对的稳定性。实验结果将为鉴定签字笔和圆珠笔油墨种类提供了法庭科学依据。它的最大优点就在于对样品的无损性,其次还有快速、无需对样品预处理和测试方法简单等。 相似文献
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A series of polyacrylonitrile-based graphite fibers with different tensile modulus and electrical resistivity were characterized by laser confocal Raman spectroscopy. The Raman spectra of the graphite fibers were deconvolved into five constituent bands using Lorentzian peak fitting function. The Raman spectra parameters, including band position, full width at half maximum, and integrated band area, were extracted and correlated with the tensile modulus and electrical resistivity. Most of the Raman parameters changed monotonically with the tensile modulus and electrical resistivity. A good linear relationship between the electrical resistivity and the structural order was found. 相似文献
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The low-frequency Raman scattering spectra of the DKDP ferroelectric crystal are studied in the temperature range 30–393 K. At temperatures above 150 K, the Raman spectra exhibit a central peak which reflects the lattice relaxation susceptibility. The width and integrated intensity of the central peak are derived from the experimental spectra. The critical slowing down of the relaxation response predicted by the Ginzburg-Landau-Devonshire theory is observed throughout the temperature range in which the central peak persists. Its integrated intensity does not, however, follow the predictions of the theory and reveals a strong temperature dependence in the ferroelectric phase and a weaker dependence in the paraphase. It is shown that the thermal activation law describes well the temperature dependence of the intensity of the central peak. An interpretation is proposed according to which the intensity of order parameter fluctuations is related to the activation barrier whose height is proportional to the deviation from the phase transition temperature. 相似文献
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通过拉曼散射光谱,吸收光谱,荧光发射寿命和808 nm LD激发下的红外荧光光谱的实验测量,系统研究了Nd3+:SrMoO4晶体的自受激拉曼光谱性质.分析指认了拉曼散射光谱中各拉曼峰所对应的晶格振动模式,得出了其SRS活性最强的声子频率约为898 cm-1,对应于(MoO2-4)离子团的完全对称光学伸缩振动Ag模;通过J-O理论对晶体的吸收谱进行了全面的光谱参数计算,得出4F3/2→4I11/2跃迁的积分发射截面达0.57×10-18 cm2,自发辐射概率为141.06 s-1;同时,实验测得该跃迁的荧光发射寿命约为0.2 ms.最后,结合808 nm LD激发下的红外波段荧光光谱,论证了SrMoO4晶体中Nd3+离子1068 nm发射通过拉曼频移获得1180 nm一级斯托克斯激光发射的可能性,为Nd3+:SrMoO4晶体的自受激拉曼激光器研究提供了理论依据.
关键词:
3+离子')" href="#">d3+离子
4 晶体')" href="#">SrMoO4 晶体
自受激拉曼散射 相似文献
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Julian J. Schuster Stefan Will Alfred Leipertz Andreas Braeuer 《Journal of Raman spectroscopy : JRS》2014,45(3):246-252
The paper reports on a routine to extract the composition of multi‐component mixtures from their Raman spectra at elevated pressures. The strategy is based on fitting weighted Raman spectra of the pure compounds to the measured Raman spectrum of the mixture, also considering the effects of intermolecular interactions onto the Raman spectra by applying Gaussian and Voigt profile deconvolution of the Raman peaks. Thereby, an improved accuracy compared to previous evaluation strategies could be obtained. The more accurate data of the ternary mixtures of carbon dioxide, water and organic solvents are presented. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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测量了不同浓度杂质水的拉曼光谱的,并与蒸馏水的拉曼光谱线进行比较和分析.结果表明,水中所含杂质的浓度越高其对应拉曼谱线弯曲振动的强度就越大,弯曲振动与伸缩振动的强度比也越大,而且拉曼光谱线峰下的面积也随着杂质浓度的增大而增加. 相似文献
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The inelastic light scattering spectra of the europium chalcogenides are analyzed in terms of a one phonon-one spin Raman process. Calculations are presented for the temperature dependence of the integrated intensity of the “spin-disorder” spectrum of EuS and compared with experiment. The observed temperature dependence of the Raman spectrum of EuSe in the two-sublattice antiferromagnetic phase is presented and examined in terms of the one phonon-one spin mechanism. Experiments are suggested in which the Raman spectra can be used to measure the magnetic field dependence of the order parameter exponent β in EuTe. 相似文献