In this work, a new TeO2-BaO-BaF2-La2O3-LaF3 oxyfluorotellurite glass system is investigated. Differential thermal analysis (DTA) and structural analysis by Raman scattering spectra are reported on the glasses. The DT...In this work, a new TeO2-BaO-BaF2-La2O3-LaF3 oxyfluorotellurite glass system is investigated. Differential thermal analysis (DTA) and structural analysis by Raman scattering spectra are reported on the glasses. The DTA results indicated that an increase of fluoride content in the glasses decreases the glass transition temperature (Tg) and increases the crystallization onset temperature (Tx). As a result the 70TeO2·20BaF2·10LaF3 glass showed a large Hruby's parameter, possessing excellent thermal stability. Changes in glass network structure with fluoride content are discussed based on the Raman scattering spectra of glasses. The glass network structures in the 70TeO2·4(20-x)BaO·xBaF2·(10-y)La2O3·yaF3 glasses are basically composed of both Te(O, F)4 and Te(O, F)3 units, but the Te(O, F)4/Te(O, F)3 ratio in the glass becomes higher with increasing fluoride content. This may be considered one of the reasons why the 70TeO2·20BaF2·10LaF3 glass exhibits excellent thermal stability.展开更多
Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have bee...Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have been analysed by means of the site group analysis method of group theory.The experimental vibrational modes have been assigned to A_g,B_g,E_g,A_u and E_u of crystal factor group C_(4h).Because the energies of stretching vibrational modes of(WO_4)^(2-)ion groups are very high(in the range of 755~940 cm^(-1)),multiphonon nonradiative transitions of ~5D_2→~5D_1 and ~5D_1→~5D_0 in Eu^(3+)will occur.So it causes Eu^(3+)ions in Na_5Eu(WO_4)_4 to emit ~5D_0→~5F_j(j=1,2,3,4)emissions mainly at room temperature and the emission light of Na_5Eu( WO_4)_4 has high red colour purity.展开更多
Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on (100) GaAs substrates by molecular beam epitaxy. Polarized Raman...Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on (100) GaAs substrates by molecular beam epitaxy. Polarized Raman spectra were recorded on the three samples at temperatures in a range of 4-50 K in a backscattering configuration. The two branches of coupled modes due to the interaction of the hole intersubband transitions and the quantum-well longitudinal optical (LO) phonon were observed clearly. The evaluation formalism of the Green function was employed and each lineshape of the Raman spectrum of the coupled modes was simulated. The dependence of the peak position of Raman shifts of the two coupled modes as well as the quantum-well LO phonon on the quantum-well size and measured temperature were given, and the coupling interaction mechanism between the hole subband transitions and the quantum-well LO phonon was researched.展开更多
As we know, there are three structures-sⅠ, sⅡ, and sH, with hydrocarbonate gas hydrate.Because of those special structures characteristics and potentail large fossil energy resource, gas hydrate play an important ro...As we know, there are three structures-sⅠ, sⅡ, and sH, with hydrocarbonate gas hydrate.Because of those special structures characteristics and potentail large fossil energy resource, gas hydrate play an important role in natural carbonate cycle system. In this paper, CH4, CO2, C3H8, and CH4 +CO2 system have been experimental performed in order to model hydrate formation and discomposition and to obtain hydrate stability conditions of tempreature and pressure. The results from laboratory using Raman spectra show that Raman spectrascopy is a effective tool to identify hydrate structure. Raman spectra of clathrate hydrate guest molecules are presented for two structure (sⅠ and sⅡ) in the following systems: CH4, CO2, C3 H8. Relatively occupancy of CH4 in the large and small cavities of sⅠ were determined by deconvoluting the v1 symmetric bands, resulting in hydration numbers of 6.04±0.03. The freqyuency of the v1 bands for CH4 in structures Ⅰ and Ⅱ differ statistically. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities.展开更多
The distribution of metal nanoparticles on the surface of a surface enhancement Raman scattering(SERS)-active substrate plays a prominent part in not only the enhancement of Raman vibration signal,but also the spectru...The distribution of metal nanoparticles on the surface of a surface enhancement Raman scattering(SERS)-active substrate plays a prominent part in not only the enhancement of Raman vibration signal,but also the spectrum uniformity.Here,a facile method to fabricate SERS substrates with excellent homogeneity and low cost was proposed,in which a lyotropic liquid crystal soft template was introduced for the coordinated growth of the silver nanoflowers in the process of electrochemistry deposition.Simulation was carried out to illustrate the dominated influence of the distance of electrodes on the deposited nanoparticle number.Two kinds of conductive materials,silver plate and indium tin oxide(ITO)glass,were chosen as the anode,while the cathode was fixed as ITO glass.The simulated conjecture on the effect of electrode flatness on the uniformity of deposited nanoparticles in silver is experimentally proved.More importantly,it was demonstrated that with a relatively smooth and flat ITO glass anode,a SERS substrate featuring higher spectrum uniformity could be achieved.This work is of great significance to the actual applications of the SERS substrate for quantitative detection with high sensitivity.展开更多
Crystal structure of tetra(1,10-Phenanthroline)neodymium (Ⅲ) tetra(4-aminobenzoate)-hydrate, [Nd(p-ABA)4·2Phen]H+3O·2Phen (p-ABA:p-aminobenzoate,Phen:1,10-phenanthroline) has been determined by X-ray diffra...Crystal structure of tetra(1,10-Phenanthroline)neodymium (Ⅲ) tetra(4-aminobenzoate)-hydrate, [Nd(p-ABA)4·2Phen]H+3O·2Phen (p-ABA:p-aminobenzoate,Phen:1,10-phenanthroline) has been determined by X-ray diffraction.The complex crystallizes in monoclinic, space group C2/c.The cell dimensions are a=1.9067 (5) nm,b=1.9192 (3) nm,c=2.0190 (4) nm,β=117.25 (2) °.V=6.568 (3) nm3, Mr= 1428.63,Z=4 and Dx= 1.45 g·cm-3.The coordination number of Nd atom is 10, and the coordinated polyhedron around the Nd atom is distorted trigonal prism.展开更多
The Raman spectrum of rhombohedral NdAl 3 (BO 3) 4 (NAB) is recorded and interpreted. A factor group analysis of the NAB space group shows that there are 21A 1 and 59E Raman active modes. A discussion of ...The Raman spectrum of rhombohedral NdAl 3 (BO 3) 4 (NAB) is recorded and interpreted. A factor group analysis of the NAB space group shows that there are 21A 1 and 59E Raman active modes. A discussion of the assignment of the individual Raman lines is given. The splitting predicted by factor group for the internal modes of (BO 3) 3+ anion are observed and interpreted.展开更多
Tip-enhanced Raman spectrum(TERS) is a scanning probe technique for acquiring chemical information at high spatial resolution and with high chemical sensitivity. The sensitivity of TERS with atomic force microscopy(AF...Tip-enhanced Raman spectrum(TERS) is a scanning probe technique for acquiring chemical information at high spatial resolution and with high chemical sensitivity. The sensitivity of TERS with atomic force microscopy(AFM) system is mainly determined by the metalized tips. Here, we report a fabrication protocol for AFM-TERS tips that incorporate a copper(Cu) primer film between a gold(Au) layer and a Si AFM tip. They were fabricated by coating the Si tip with a 2 nm Cu layer prior to adding a 20 nm Au layer. For top illumination TERS experiments, these tips exhibited superior TERS performance relative to that observed for tips coated with Au only. Samples included graphene, thiophenol and brilliant cresyl blue. The results may derive from the surface roughness of the tip apex and a Cu/Au synergism of local surface plasmon resonances.展开更多
Abstract: The Raman scattering spectra of n- type GaP(doped S) single crystal and red and green luminous materials grown on the n - type GaP (doped S) single crys-tal substrate by liquid - phase epitaxy are analyed. T...Abstract: The Raman scattering spectra of n- type GaP(doped S) single crystal and red and green luminous materials grown on the n - type GaP (doped S) single crys-tal substrate by liquid - phase epitaxy are analyed. The results show that the spectra of GaP single crystal and its luminous materials include not only the first - order longitudi-nal optical photons and transverse optical phonons Raman scattering peaks, but also the peaks of the bound excitons, bound electrons and bound holes.展开更多
We present an experimental study on low-threshold broadband spectrum generation mainly due to the amplirfication of the cascaded stimulated Raman scattering (SRS) effect in a four-stage fiber master oscillator power...We present an experimental study on low-threshold broadband spectrum generation mainly due to the amplirfication of the cascaded stimulated Raman scattering (SRS) effect in a four-stage fiber master oscillator power amplifier system. The cascaded SRS is achieved by using a long passive fiber pumped by a pulsed fiber laser cen: tered at wavelength 1064 nm. The amplified spontaneous emission during the amplification process is efficiently suppressed by cutting the length of the passive fiber and by using a double-clad ytterbium-doped fiber amplifier. The generated broadband spectrum spans from 960nm to 1700nm with maximum average output 13.6 W and average spectral power density approximately 17. 7 mW/nm.展开更多
The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of...The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of nano-SnO2 with the results of amorphous film and single crystal of SnO2 it is found that the new Raman peaks N1 and N2 are in accordance with Matossi’s force constant model completely.When the annealing temperature is near 673K,the local lattice disorders and the density of vacant lattice decrease rapidly in the nano-SnO2 grains.The lattice distortion and the new Raman peaks disappear almost at the same time.The possible mechanisms of the microstructural change and the new Raman peaks NI and N2 are discussed.展开更多
目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷...目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。展开更多
基金This work was supported by the National Natural Science Foundation of China under grant No.60207006the Optical Science and Technology of Shanghai under grant No.022261046"Qiningxing”Projert(No.04QMX1448)of Shanghai Municipal Science and Technology Conmission.
文摘In this work, a new TeO2-BaO-BaF2-La2O3-LaF3 oxyfluorotellurite glass system is investigated. Differential thermal analysis (DTA) and structural analysis by Raman scattering spectra are reported on the glasses. The DTA results indicated that an increase of fluoride content in the glasses decreases the glass transition temperature (Tg) and increases the crystallization onset temperature (Tx). As a result the 70TeO2·20BaF2·10LaF3 glass showed a large Hruby's parameter, possessing excellent thermal stability. Changes in glass network structure with fluoride content are discussed based on the Raman scattering spectra of glasses. The glass network structures in the 70TeO2·4(20-x)BaO·xBaF2·(10-y)La2O3·yaF3 glasses are basically composed of both Te(O, F)4 and Te(O, F)3 units, but the Te(O, F)4/Te(O, F)3 ratio in the glass becomes higher with increasing fluoride content. This may be considered one of the reasons why the 70TeO2·20BaF2·10LaF3 glass exhibits excellent thermal stability.
文摘Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have been analysed by means of the site group analysis method of group theory.The experimental vibrational modes have been assigned to A_g,B_g,E_g,A_u and E_u of crystal factor group C_(4h).Because the energies of stretching vibrational modes of(WO_4)^(2-)ion groups are very high(in the range of 755~940 cm^(-1)),multiphonon nonradiative transitions of ~5D_2→~5D_1 and ~5D_1→~5D_0 in Eu^(3+)will occur.So it causes Eu^(3+)ions in Na_5Eu(WO_4)_4 to emit ~5D_0→~5F_j(j=1,2,3,4)emissions mainly at room temperature and the emission light of Na_5Eu( WO_4)_4 has high red colour purity.
基金Project supported by Shandong Province Natural Science Foundation,China(Grant No.ZR2017MF018)the National Natural Science Foundation of China(Grant No.61675223)
文摘Three samples of GaAs/A1As multiple-quantum wells with different quantum well widths and tS-doped with Be ac- ceptors at the well center were grown on (100) GaAs substrates by molecular beam epitaxy. Polarized Raman spectra were recorded on the three samples at temperatures in a range of 4-50 K in a backscattering configuration. The two branches of coupled modes due to the interaction of the hole intersubband transitions and the quantum-well longitudinal optical (LO) phonon were observed clearly. The evaluation formalism of the Green function was employed and each lineshape of the Raman spectrum of the coupled modes was simulated. The dependence of the peak position of Raman shifts of the two coupled modes as well as the quantum-well LO phonon on the quantum-well size and measured temperature were given, and the coupling interaction mechanism between the hole subband transitions and the quantum-well LO phonon was researched.
基金Supported by the National Natural Science Foundation of China (No. 49973024, 40272066)211 Projects of Xiamen University.
文摘As we know, there are three structures-sⅠ, sⅡ, and sH, with hydrocarbonate gas hydrate.Because of those special structures characteristics and potentail large fossil energy resource, gas hydrate play an important role in natural carbonate cycle system. In this paper, CH4, CO2, C3H8, and CH4 +CO2 system have been experimental performed in order to model hydrate formation and discomposition and to obtain hydrate stability conditions of tempreature and pressure. The results from laboratory using Raman spectra show that Raman spectrascopy is a effective tool to identify hydrate structure. Raman spectra of clathrate hydrate guest molecules are presented for two structure (sⅠ and sⅡ) in the following systems: CH4, CO2, C3 H8. Relatively occupancy of CH4 in the large and small cavities of sⅠ were determined by deconvoluting the v1 symmetric bands, resulting in hydration numbers of 6.04±0.03. The freqyuency of the v1 bands for CH4 in structures Ⅰ and Ⅱ differ statistically. The large cavities were measured to be almost fully occupied by CH4 and CO2, whereas only a small fraction of the small cavities are occupied by CH4. No CO2 was found in the small cavities.
基金supported by the Jiangsu Key Disciplines of the Fourteenth Five-Year Plan(No.2021135)the National Natural Science Foundation of China(No.22205155)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220640)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.22KJB150011)。
文摘The distribution of metal nanoparticles on the surface of a surface enhancement Raman scattering(SERS)-active substrate plays a prominent part in not only the enhancement of Raman vibration signal,but also the spectrum uniformity.Here,a facile method to fabricate SERS substrates with excellent homogeneity and low cost was proposed,in which a lyotropic liquid crystal soft template was introduced for the coordinated growth of the silver nanoflowers in the process of electrochemistry deposition.Simulation was carried out to illustrate the dominated influence of the distance of electrodes on the deposited nanoparticle number.Two kinds of conductive materials,silver plate and indium tin oxide(ITO)glass,were chosen as the anode,while the cathode was fixed as ITO glass.The simulated conjecture on the effect of electrode flatness on the uniformity of deposited nanoparticles in silver is experimentally proved.More importantly,it was demonstrated that with a relatively smooth and flat ITO glass anode,a SERS substrate featuring higher spectrum uniformity could be achieved.This work is of great significance to the actual applications of the SERS substrate for quantitative detection with high sensitivity.
文摘Crystal structure of tetra(1,10-Phenanthroline)neodymium (Ⅲ) tetra(4-aminobenzoate)-hydrate, [Nd(p-ABA)4·2Phen]H+3O·2Phen (p-ABA:p-aminobenzoate,Phen:1,10-phenanthroline) has been determined by X-ray diffraction.The complex crystallizes in monoclinic, space group C2/c.The cell dimensions are a=1.9067 (5) nm,b=1.9192 (3) nm,c=2.0190 (4) nm,β=117.25 (2) °.V=6.568 (3) nm3, Mr= 1428.63,Z=4 and Dx= 1.45 g·cm-3.The coordination number of Nd atom is 10, and the coordinated polyhedron around the Nd atom is distorted trigonal prism.
文摘The Raman spectrum of rhombohedral NdAl 3 (BO 3) 4 (NAB) is recorded and interpreted. A factor group analysis of the NAB space group shows that there are 21A 1 and 59E Raman active modes. A discussion of the assignment of the individual Raman lines is given. The splitting predicted by factor group for the internal modes of (BO 3) 3+ anion are observed and interpreted.
基金supported by the National Basic Research Program of China(2011YQ03012415,2011CB808700)the National Natural Science Foundation of China(21127901,233010,21121063)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12020100)
文摘Tip-enhanced Raman spectrum(TERS) is a scanning probe technique for acquiring chemical information at high spatial resolution and with high chemical sensitivity. The sensitivity of TERS with atomic force microscopy(AFM) system is mainly determined by the metalized tips. Here, we report a fabrication protocol for AFM-TERS tips that incorporate a copper(Cu) primer film between a gold(Au) layer and a Si AFM tip. They were fabricated by coating the Si tip with a 2 nm Cu layer prior to adding a 20 nm Au layer. For top illumination TERS experiments, these tips exhibited superior TERS performance relative to that observed for tips coated with Au only. Samples included graphene, thiophenol and brilliant cresyl blue. The results may derive from the surface roughness of the tip apex and a Cu/Au synergism of local surface plasmon resonances.
文摘Abstract: The Raman scattering spectra of n- type GaP(doped S) single crystal and red and green luminous materials grown on the n - type GaP (doped S) single crys-tal substrate by liquid - phase epitaxy are analyed. The results show that the spectra of GaP single crystal and its luminous materials include not only the first - order longitudi-nal optical photons and transverse optical phonons Raman scattering peaks, but also the peaks of the bound excitons, bound electrons and bound holes.
基金Supported by the National Natural Science Foundation of China under Grant No 11404404the Outstanding Youth Fund Project of Hunan Provincethe Fund of Innovation of National University of Defense Technology under Grant No B120701
文摘We present an experimental study on low-threshold broadband spectrum generation mainly due to the amplirfication of the cascaded stimulated Raman scattering (SRS) effect in a four-stage fiber master oscillator power amplifier system. The cascaded SRS is achieved by using a long passive fiber pumped by a pulsed fiber laser cen: tered at wavelength 1064 nm. The amplified spontaneous emission during the amplification process is efficiently suppressed by cutting the length of the passive fiber and by using a double-clad ytterbium-doped fiber amplifier. The generated broadband spectrum spans from 960nm to 1700nm with maximum average output 13.6 W and average spectral power density approximately 17. 7 mW/nm.
基金Project supported by the Foundation of State Science and Technology and the Natural Science Foundation of Anhui Province.
文摘The dependence of the microstructural change and lattice space symmetry of nano-SnO2 on the annealing temperature has been studied systematically using Raman spectroscopy and X-ray diffraction.Comparing the results of nano-SnO2 with the results of amorphous film and single crystal of SnO2 it is found that the new Raman peaks N1 and N2 are in accordance with Matossi’s force constant model completely.When the annealing temperature is near 673K,the local lattice disorders and the density of vacant lattice decrease rapidly in the nano-SnO2 grains.The lattice distortion and the new Raman peaks disappear almost at the same time.The possible mechanisms of the microstructural change and the new Raman peaks NI and N2 are discussed.
文摘目的利用拉曼光谱与中红外光谱的数据融合技术实现对食用酒精乙醇浓度(酒精度)的快速定量检测。方法首先,分别采集不同浓度食用酒精水溶液的拉曼光谱与中红外光谱。其次,采用多元散射校正(multiplicative scatter correction,MSC)、卷积平滑(Savitzky-Golay,S-G)、一阶求导的方法对原始数据进行预处理。然后,基于自举软缩减法(bootstrapping soft shrinkage,BOSS)和无信息变量消除算法(uninformative variable elimination,UVE)分别对预处理后的光谱数据进行特征提取,并利用X-Y距离样本集划分法(sample set partitioning based on joint X-Y distance,SPXY)将光谱数据划分为校正集和预测集。最后,建立基于拉曼光谱-中红外光谱数据融合的偏最小二乘回归(partial least squares regression,PLSR)食用酒精乙醇浓度预测模型,并利用麻雀搜寻算法优化的混合核极限学习机算法(sparrow search algorithm-optimized hybrid kernel extreme learning machine,SSA-HKELM)提升预测性能,实现对不同浓度食用酒精的快速、准确定量检测。结果与拉曼光谱数据、中红外光谱数据以及中红外与拉曼光谱的数据层融合构建的预测模型相比,中红外光谱与拉曼光谱特征层融合数据构建的预测模型具有更好的预测性能。其中,最优模型的校正集均方根误差(root mean squared error of calibration set,RMSEC)为0.98314,校正集决定系数(R_(c)^(2))为0.99634,预测集均方根误差(root mean squared error of prediction set,RMSEP)为1.03256,预测集决定系数(R_(p)^(2))为0.99036。结论中红外光谱与拉曼光谱特征层融合预测模型可以实现对不同浓度食用酒精的高效定量检测,为食用酒精的质量检测提供了有效的理论支持与技术保障。