Veins and clasts of pseudotachylyte developed in the microbreccias of the detachment fault along the boundary of the Xiaoqinling metamorphic core complex. The Raman spectral analysis shows that there are three kinds o...Veins and clasts of pseudotachylyte developed in the microbreccias of the detachment fault along the boundary of the Xiaoqinling metamorphic core complex. The Raman spectral analysis shows that there are three kinds of textures in the matrices of the pseudotachylyte, i.e. ultracataclastic fine grained texture, cryptocrystalline texture and both of them with minute quantity of glass. The three different textures are the results of different degrees of ultracataclasis. This demonstrates that ultracataclasis comminution melting is the genetic mechanism of the pseudotachylytes in the Xiaoqinling detachment fault and the ultracataclasis comminution dominates in their formation.展开更多
To realize the fast and accurate quantitative analysis of the mixture of polycyclic aromatic hydrocarbons(PAHs),surface-enhanced Raman spectroscopy(SERS)coupled with multivariate calibrations were employed.In this stu...To realize the fast and accurate quantitative analysis of the mixture of polycyclic aromatic hydrocarbons(PAHs),surface-enhanced Raman spectroscopy(SERS)coupled with multivariate calibrations were employed.In this study,three kinds of calibration algorithms were used to quantitative analysis of the mixture of naphthalene(Nap),phenanthrene(Phe),and pyrene(Pyr).Firstly,partial least squares(PLS)algorithm was used to select characteristic variables,then the global search capability of genetic algorithm(GA)was used for the determining of the initial weights and thresholds of back propagation(BP)neural network so that local minima was avoided.The PLS-GA-BP model exhibited superiority to quantify PAHs mixture,which achieved R2=0.9975,0.9710,0.9643,ARE=10.07%,19.28%,16.72%and RMSE=13.10,5.40,5.10 nmol L−1 for Nap,Phe,Pyr(in the PAHs mixture)concentration prediction respectively.The forecast error,ARE and RMSE have been reduced more than 50%and 60%respectively compared with the whole spectral BP model.The study indicates that accurate quantitative spectroscopic analysis of the mixture of PAHs samples can be achieved through the combination of SERS technique and PLS-GA-BP algorithm.展开更多
A comprehensive study on Raman spectroscopy with different excitation wavelengths, sample sizes, and sample shapes for optic phonons （OPs） and acoustic phonons （APs） in polar and non-polar nano-semiconductors has ...A comprehensive study on Raman spectroscopy with different excitation wavelengths, sample sizes, and sample shapes for optic phonons （OPs） and acoustic phonons （APs） in polar and non-polar nano-semiconductors has been performed. The study affirms that the finite size effect does not appear in the OPs of polar nano-semiconductors, while it exists in all other types of phonons. The absence of the FSE is confirmed to originate from the long-range FrShlieh interaction and the breaking of translation symmetry. The result indicates that the Raman spectra of OPs cannot be used as a method to characterize the scale and crystalline property of polar nano-semiconductors.展开更多
Surface-enhanced resonance Raman scattering （SERRS） of Rhodamine 6G （R6G） adsorbed on colloidal silver clusters has been studied. Based on the great enhancement of the Raman signal and the quench of the fluorescen...Surface-enhanced resonance Raman scattering （SERRS） of Rhodamine 6G （R6G） adsorbed on colloidal silver clusters has been studied. Based on the great enhancement of the Raman signal and the quench of the fluorescence, the SERRS spectra of R6G were recorded for the samples of dye colloidal solution with different concentrations. Spectral inhomogeneity behaviours from single molecules in the dried sample films were observed with complementary evidences, such as spectral polarization, spectral diffusion, intensity fluctuation of vibrational lines and even ＂breathing＂ of the molecules. Sequential spectra observed from a liquid sample with an average of 0.3 dye molecules in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1 or 2 molecules. Difference between the SERRS spectra of R6G excited by linearly and circularly polarized light were experimentally measured.展开更多
Smoothing by spectral dispersion （SSD） leads to considerable improvement on laser-irradiation uniformity in far field for fusion lasers. Phase modulation in time and spectral angular dispersion （SAD） across the be...Smoothing by spectral dispersion （SSD） leads to considerable improvement on laser-irradiation uniformity in far field for fusion lasers. Phase modulation in time and spectral angular dispersion （SAD） across the beam introduced by SSD will affect the stimulated rotational Raman scattering （SRRS） gain in the near field. This paper focuses on the influence of SAD on SRRS gain under different laser conditions. Results show that the SAD will aggravate the generation of SRRS when the laser initial additional phase is constant. On the contrary, the SAD can reduce the SRRS gain if appropriate SSD parameters are adopted when the laser initial additional phase is variable. SSD has a certain application prospect in SRRS suppression.展开更多
目的在近红外光谱(near infrared spectroscopy,NIR)与表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)特征层数据融合的基础上构建偏最小二乘回归(partial least squares regression,PLSR)模型实现花生油中黄曲霉毒素B_(1...目的在近红外光谱(near infrared spectroscopy,NIR)与表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)特征层数据融合的基础上构建偏最小二乘回归(partial least squares regression,PLSR)模型实现花生油中黄曲霉毒素B_(1)(aflatoxin B_(1),AFB_(1))含量的快速检测。方法首先,分别采集待测样本的NIR与SERS光谱。其次,将采集的NIR与SERS光谱分别进行光谱预处理。然后,采用基于希尔伯特-施密特独立准则的变量空间迭代优化算法(Hilbert-Schmidt independence criterion based variable space iterative optimization,HSIC-VSIO)分别筛选NIR与SERS光谱的特征变量。最后,将筛选的特征变量进行融合并构建PLSR模型用于定量检测花生油中AFB_(1)含量。结果与NIR光谱数据、SERS光谱数据以及NIR与SERS光谱直接融合数据构建的PLSR模型相比,NIR与SERS光谱特征层融合数据构建的PLSR模型具有最佳的预测性能:校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.1569,校正集决定系数(coefficient of determination of calibration set,R_(c)^(2))为0.9908,预测集均方根误差(root mean squared error of prediction set,RMSEP)为0.1827,预测集决定系数(coefficient of determination of prediction set,R_(c)^(2))为0.9854,性能偏差比(ratio of performance to deviation,RPD)为8.2761。将本方法与标准方法分别检测真实含有AFB_(1)的花生油样本,结果表明两者的检测性能无显著性差异(P=0.84>0.05)。结论本方法可实现花生油中AFB_(1)含量的快速、高精度定量检测,也验证了NIR与SERS光谱融合的可行性与有效性。展开更多
文摘Veins and clasts of pseudotachylyte developed in the microbreccias of the detachment fault along the boundary of the Xiaoqinling metamorphic core complex. The Raman spectral analysis shows that there are three kinds of textures in the matrices of the pseudotachylyte, i.e. ultracataclastic fine grained texture, cryptocrystalline texture and both of them with minute quantity of glass. The three different textures are the results of different degrees of ultracataclasis. This demonstrates that ultracataclasis comminution melting is the genetic mechanism of the pseudotachylytes in the Xiaoqinling detachment fault and the ultracataclasis comminution dominates in their formation.
基金National Natural Sci ence Foundation of China(No.41476081)the Major Research and Development Project in Shandong Province(No.2019GHY112027)the Shandong Provincial Natural Science Foundation(No.ZR2020MF121).
文摘To realize the fast and accurate quantitative analysis of the mixture of polycyclic aromatic hydrocarbons(PAHs),surface-enhanced Raman spectroscopy(SERS)coupled with multivariate calibrations were employed.In this study,three kinds of calibration algorithms were used to quantitative analysis of the mixture of naphthalene(Nap),phenanthrene(Phe),and pyrene(Pyr).Firstly,partial least squares(PLS)algorithm was used to select characteristic variables,then the global search capability of genetic algorithm(GA)was used for the determining of the initial weights and thresholds of back propagation(BP)neural network so that local minima was avoided.The PLS-GA-BP model exhibited superiority to quantify PAHs mixture,which achieved R2=0.9975,0.9710,0.9643,ARE=10.07%,19.28%,16.72%and RMSE=13.10,5.40,5.10 nmol L−1 for Nap,Phe,Pyr(in the PAHs mixture)concentration prediction respectively.The forecast error,ARE and RMSE have been reduced more than 50%and 60%respectively compared with the whole spectral BP model.The study indicates that accurate quantitative spectroscopic analysis of the mixture of PAHs samples can be achieved through the combination of SERS technique and PLS-GA-BP algorithm.
基金Project supported by the National Basic Research Program of China (Grants Nos. 2009CB929403 and 2012CB825700)the National Natural Science Foundation of China (Grants Nos. 10774006 and 60876002)
文摘A comprehensive study on Raman spectroscopy with different excitation wavelengths, sample sizes, and sample shapes for optic phonons （OPs） and acoustic phonons （APs） in polar and non-polar nano-semiconductors has been performed. The study affirms that the finite size effect does not appear in the OPs of polar nano-semiconductors, while it exists in all other types of phonons. The absence of the FSE is confirmed to originate from the long-range FrShlieh interaction and the breaking of translation symmetry. The result indicates that the Raman spectra of OPs cannot be used as a method to characterize the scale and crystalline property of polar nano-semiconductors.
文摘Surface-enhanced resonance Raman scattering （SERRS） of Rhodamine 6G （R6G） adsorbed on colloidal silver clusters has been studied. Based on the great enhancement of the Raman signal and the quench of the fluorescence, the SERRS spectra of R6G were recorded for the samples of dye colloidal solution with different concentrations. Spectral inhomogeneity behaviours from single molecules in the dried sample films were observed with complementary evidences, such as spectral polarization, spectral diffusion, intensity fluctuation of vibrational lines and even ＂breathing＂ of the molecules. Sequential spectra observed from a liquid sample with an average of 0.3 dye molecules in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1 or 2 molecules. Difference between the SERRS spectra of R6G excited by linearly and circularly polarized light were experimentally measured.
基金Project supported by the State Key Program of the National Natural Science Foundation of China(Grant No.61138005)the National Natural Science Foundation of China(Grant No.61008004)
文摘Smoothing by spectral dispersion （SSD） leads to considerable improvement on laser-irradiation uniformity in far field for fusion lasers. Phase modulation in time and spectral angular dispersion （SAD） across the beam introduced by SSD will affect the stimulated rotational Raman scattering （SRRS） gain in the near field. This paper focuses on the influence of SAD on SRRS gain under different laser conditions. Results show that the SAD will aggravate the generation of SRRS when the laser initial additional phase is constant. On the contrary, the SAD can reduce the SRRS gain if appropriate SSD parameters are adopted when the laser initial additional phase is variable. SSD has a certain application prospect in SRRS suppression.
文摘目的在近红外光谱(near infrared spectroscopy,NIR)与表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)特征层数据融合的基础上构建偏最小二乘回归(partial least squares regression,PLSR)模型实现花生油中黄曲霉毒素B_(1)(aflatoxin B_(1),AFB_(1))含量的快速检测。方法首先,分别采集待测样本的NIR与SERS光谱。其次,将采集的NIR与SERS光谱分别进行光谱预处理。然后,采用基于希尔伯特-施密特独立准则的变量空间迭代优化算法(Hilbert-Schmidt independence criterion based variable space iterative optimization,HSIC-VSIO)分别筛选NIR与SERS光谱的特征变量。最后,将筛选的特征变量进行融合并构建PLSR模型用于定量检测花生油中AFB_(1)含量。结果与NIR光谱数据、SERS光谱数据以及NIR与SERS光谱直接融合数据构建的PLSR模型相比,NIR与SERS光谱特征层融合数据构建的PLSR模型具有最佳的预测性能:校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.1569,校正集决定系数(coefficient of determination of calibration set,R_(c)^(2))为0.9908,预测集均方根误差(root mean squared error of prediction set,RMSEP)为0.1827,预测集决定系数(coefficient of determination of prediction set,R_(c)^(2))为0.9854,性能偏差比(ratio of performance to deviation,RPD)为8.2761。将本方法与标准方法分别检测真实含有AFB_(1)的花生油样本,结果表明两者的检测性能无显著性差异(P=0.84>0.05)。结论本方法可实现花生油中AFB_(1)含量的快速、高精度定量检测,也验证了NIR与SERS光谱融合的可行性与有效性。
文摘目的建立基于光谱融合的定性分析模型,实现高值茶油的真伪快速鉴别。方法优化设备条件,同时采集茶油的近红外光谱(near infrared spectroscopy,NIRS)和拉曼光谱(Raman spectroscopy,RS),分别使用6种方法进行预处理,优选4种方法来提取光谱特征波段,并应用数据层和特征层策略融合多光谱信息,通过比较验证不同模型的准确率和预测均方根误差(root mean square error of prediction,RMSEP)来评估效果。结果单独使用NIRS经标准正态变换处理后的偏最小二乘判别分析结果最优,准确率为0.8361,RMSEP为0.1060;单独使用RS经二阶导数处理后的结果最优,准确率为0.8443,RMSEP为0.1332;经NIRS和RS融合后数据结果高于任意单一光谱结果,其中数据层光谱融合模型准确率为0.8525,RMSEP为0.1270,特征层融合后的模型效果较好,最佳结果为基于核主成分分析下的支持向量机模型,准确率达到0.9508。结论光谱融合提升茶油掺伪定性鉴别准确率更高,具有较好的应用前景。
