Journals >Spectroscopy and Spectral Analysis
Contents
2013
Volume: 33 Issue 5
62 Article(s)
Export citation format
Research Article
Investigation of the Temperature-Dependent Spectral Characteristics of Colloidal PbSe Nanocrystals
WANG Fang-rong, FAN Wen-yong, ZHAI Wei-wei, ZHANG Tie-qiang, WANG Yi-ding, and ZHANG Yu
In the present paper colloidal PbSe nanocrystals were prepared with the particle size of 3.8 and 5.8 nm, and the temperature- dependent optical properties of colloidal PbSe nanocrystals were investigated. The experimental data show that the band gap, photoluminescence peak wavelength, photoluminescence intensity and fuIn the present paper colloidal PbSe nanocrystals were prepared with the particle size of 3.8 and 5.8 nm, and the temperature- dependent optical properties of colloidal PbSe nanocrystals were investigated. The experimental data show that the band gap, photoluminescence peak wavelength, photoluminescence intensity and full width at half-maximum of colloidal PbSe nanocrystals will change with variations in temperature and size at room temperature. The band gap of colloidal PbSe nanocrystals with the particle size of 3.8 nm shifts towards red when the temperature increases. However, the blue shift occurs when the particle size is 5.8 nm. The photoluminescence intensity of colloidal PbSe nanocrystals drops and the full width at half-maximum will increases with the increase in temperature..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1153 (2013)
Study of the Microwave Emissivity Characteristics of Vegetation over the Northern Hemisphere
SHI Li-juan, QIU Yu-bao, and SHI Jian-cheng
The microwave emissivity is a function of structure, water content, and surface roughness, and all these factors have obvious seasonal variations. In the present study, the half-month averaged emissivities in summer and winter of 2003 over the vegetation of Northern Hemisphere were estimated using Advanced Microwave ScThe microwave emissivity is a function of structure, water content, and surface roughness, and all these factors have obvious seasonal variations. In the present study, the half-month averaged emissivities in summer and winter of 2003 over the vegetation of Northern Hemisphere were estimated using Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) combined with IGBP (International Geosphere-Biosphere Project labels) land classification data. Then the emissivities of vegetation land covers at different frequencies, the polarization and their seasonal variations were analyzed respectively. The results show that the emissivities of vegetation increase with the increase in frequencies, and decline with the frequency increasing over snow region. In summer, the vegetation emissivity at V-polarization of 89 GHz is larger than 0.944, and all emissivities are relatively stable and the RMSE of time series emissivity variation is less than 0.007 2. In winter, emissivities decrease over snow covered area, especially for higher frequencies. Furthermore, with the increase in vegetation density, the emissivities increase and emissivity polarization difference decreases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1157 (2013)
Quartz-Enhanced Photoacoustic Spectroscopy Trace Gas Detection System Based on the Fabry-Perot Demodulation
LIN Cheng, ZHU Yong, WEI Wei, ZHANG Jie, TIAN Li, and XU Zu-wen
An all-optical quartz-enhanced photoacoustic spectroscopy system, based on the F-P demodulation, for trace gas detection in the open environment was proposed. In quartz-enhanced photoacoustic spectroscopy (QEPAS), an optical fiber Fabry-Perot method was used to replace the conventional electronic demodulation method. TAn all-optical quartz-enhanced photoacoustic spectroscopy system, based on the F-P demodulation, for trace gas detection in the open environment was proposed. In quartz-enhanced photoacoustic spectroscopy (QEPAS), an optical fiber Fabry-Perot method was used to replace the conventional electronic demodulation method. The photoacoustic signal was obtained by demodulating the variation of the Fabry-Perot cavity between the quartz tuning fork side and the fiber face. An experimental system was setup. The experiment for detection of water vapour in the open environment was carried on. A normalized noise equivalent absorption coefficient of 2.80×10-7 cm-1·W·Hz-1/2 was achieved. The result demonstrated that the sensitivity of the all-optical quartz-enhanced photoacoustic spectroscopy system is about 2.6 times higher than that of the conventional QEPAS system. The all-optical quartz-enhanced photoacoustic spectroscopy system is immune to electromagnetic interference, safe in flammable and explosive gas detection, suitable for high temperature and high humidity environments and realizable for long distance, multi-point and network sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1163 (2013)
Measurement of Active Particles Generated in a Coaxial Barrier Discharge by Spectral Method
LI Xue-chen, CHANG Yuan-yuan, and JIA Peng-ying
Coaxial dielectric barrier discharge has extensive application prospects. A dielectric barrier discharge device with water electrode was used to investigate the discharge properties and spectral intensity emitted from active particles in the air by optical method. Results indicate that the optical emission spectra consCoaxial dielectric barrier discharge has extensive application prospects. A dielectric barrier discharge device with water electrode was used to investigate the discharge properties and spectral intensity emitted from active particles in the air by optical method. Results indicate that the optical emission spectra consist of spectral lines from oxygen atoms (777.5 and 844.6 nm), which implies that oxygen atoms with high chemical activity were generated in the discharge plasma. Through spatially resolved measurements, spectral intensities from oxygen atoms were given as functions of the experimental parameters such as the value of the applied voltage, the gas flow rate and argon content. Results show that the spectral line intensity from oxygen atom increases with increasing the peak value of the applied voltage, increases with increasing the gas flow rate, reaches its maximum with a gas flow rate of 30 L·min-1 and then decreases with further increasing the gas flow rate. Similarly, the spectral line intensity increases firstly and then decreases with increasing argon content (in a mixture of argon and air) and a maximum is reached when argon content is 16.7%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1167 (2013)
Experimental Investigation of the Chemical Effect of Direct Current Arc Plasma Igniter
ZHAO Bing-bing, HE Li-ming, SHEN Ying, BAI Xiao-feng, and YU Jin-lu
To study the chemical effect of direct current arc plasma igniter, the emission spectrum of plasma jet was measured, and the active particles produced by the interaction of plasma jet with atmospheric air were analyzed. The NO and CO volume fractions were measured quantificationally by smoke analyzer at the 8cm downstrTo study the chemical effect of direct current arc plasma igniter, the emission spectrum of plasma jet was measured, and the active particles produced by the interaction of plasma jet with atmospheric air were analyzed. The NO and CO volume fractions were measured quantificationally by smoke analyzer at the 8cm downstream the plasma igniter exit, and the changing law between arc current and NO, CO volume fractions was obtained. The results show that the plasma jet interacting with atmospheric air produced active particles (H, O, N), charged particles(O2+, N2+), and excited particles(N2(A3), N2(B3), N2(C3), N2(a1), O2(a1), O2(b1)). The NO and CO volume fractions increased with rising of arc current and feedstock argon flow rate..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1171 (2013)
Preparation and Optical Properties of MgAl2O4/Ce∶YAG Transparent Ceramics
HE Long-fei, FAN Guang-han, LEI Mu-yun, LOU Zai-liang, CHEN Zhi-wu, XIAO Yao, ZHENG Shu-wen, and ZHANG Tao
High-purity ultrafine MgAl2O4 powder was synthesized by metal-alkoxide method and calcining for 2～4 h.And then MgAl2O4/Ce∶YAG tra nsparent ceramics were fabricated by hot-pressed sintering and hot isostatic pressed sintering technique with YAG∶Ce powder and MgAl2O4 powder. The tra nsparent ceramics were characterized bHigh-purity ultrafine MgAl2O4 powder was synthesized by metal-alkoxide method and calcining for 2～4 h.And then MgAl2O4/Ce∶YAG tra nsparent ceramics were fabricated by hot-pressed sintering and hot isostatic pressed sintering technique with YAG∶Ce powder and MgAl2O4 powder. The tra nsparent ceramics were characterized by XRD, SEM, EDS and fluorescence spectrometer, respectively. The results show that the crystal phase of the tra nsparent ceramic was composed of MgAl2O4 and YAG,and the YAG phase dispersed well in the matrix of MgAl2O4. The excitation spectra had a weak band at 345 nm and a strong band at 475 nm. The broad emission peaks at about 533 nm were attributed to 5d→4f tra nsition of Ce3+ io ns. Decay curves for the fluorescence of MgAl2O4/Ce∶YAG tra nsparent ceramic test show that the lifetime of the Ce∶YAG glass ceramic was 59.74 ns. All results show that MgAl2O4/Ce∶YAG tra nsparent ceramic may be a promising fluorescent material for white LED applicatio ns..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1175 (2013)
Influence of Delay Time on Laser-Induced Breakdown Spectroscopy of Limestone
WANG Yang-en
In order to study the influence of delay time on laser-induced breakdown spectroscopy(LIBS), the relationship between the intensities of the spectral line and the delay time was discussed in theory, and the LIBS instrument manufactured by Applied Spectra Inc was used for testing the limestone certified reference sampleIn order to study the influence of delay time on laser-induced breakdown spectroscopy(LIBS), the relationship between the intensities of the spectral line and the delay time was discussed in theory, and the LIBS instrument manufactured by Applied Spectra Inc was used for testing the limestone certified reference sample GBW07716. The characteristic spectral line was analyzed with MnⅠ357.788 nm, WⅡ364.141 nm, WⅠ407.436 nm, WⅠ426.938 nm and CoⅠ387.312nm.It was demonstrated that the intensities of the spectral line decrease exponentially with the delay time, and the decrease speed is not the same for different spectral line. The intensities of the ion spectral line are stronger in an early stage, but decrease faster with the increase in delay time than the atomic spectral line. The experimental data fit with exponential law and the fitting R value is about 0.99..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1180 (2013)
Effect of PbO on Emission Properties of YAG∶Ce3+ Phosphor
WANG Lei, ZHANG Jia-hua, CUI Cai-e, and HUANG Ping
Doubly doped YAG∶Ce3+, Pb2+ phosphor was obtained by doping YAG∶Ce3+ phosphor with PbO. Compared with the emission spectra of YAG∶Ce3+ phosphor without PbO, the Ce3+ emission band of YAG∶Ce3+, Pb2+ shifts to longet wave, which can enhance the red component of spectrum. Meanwhile, the intensity of Ce3+ emission is increDoubly doped YAG∶Ce3+, Pb2+ phosphor was obtained by doping YAG∶Ce3+ phosphor with PbO. Compared with the emission spectra of YAG∶Ce3+ phosphor without PbO, the Ce3+ emission band of YAG∶Ce3+, Pb2+ shifts to longet wave, which can enhance the red component of spectrum. Meanwhile, the intensity of Ce3+ emission is increased by 10% when the concentration of PbO is 5%, SEM image indicates that PbO may act as a flux. Temperature-dependent emission spectra of YAG∶Ce3+, Pb2+ phosphor show a better thermal quenching characteristics than YAG∶Ce3+ phosphor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1185 (2013)
The Research on Remote Sensing Dust Aerosol by Using Split Window Emissivity
XU Hui, YU Tao, GU Xing-fa, CHENG Tian-hai, XIE Dong-hai, and LIU Qian
Dust aerosol can cause the change in the land surface emissivity in split window by radiative forcing (RF). Firstly, the present paper explained from the microscopic point of view the extinction properties of dust aerosols in the 11 and 12 μm channels, and their influence on the land surface emissivity. Secondly, on ApDust aerosol can cause the change in the land surface emissivity in split window by radiative forcing (RF). Firstly, the present paper explained from the microscopic point of view the extinction properties of dust aerosols in the 11 and 12 μm channels, and their influence on the land surface emissivity. Secondly, on April 29, 2011, in the northern region of Inner Mongolia a strong sandstorm outbroke, and based on the analysis of the changes in land surface emissivity, this paper proposed a dust identification method by using the variation of emissivity. At last, the dust identification result was evaluated by the dust monitoring product provided by the National Satellite Meteorological Center. The result shows that under the assumption that the 12 μm emissivity equals to 1, using 11 μm relative emissivity could identify dust cover region effectively, and the 11 μm relative emissivity to a certain extent represented the intensity information of dust aerosol..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1189 (2013)
Characterization of the Different Organic Matter from Soils and Sediments
GAO Bo, ZHOU Huai-dong, JIN Jie, and SUN Ke
The humic acid (HA) and nonhydrolyzable carbons (NHC) were isolated from three river sediment samples (1, 2, 3) from the rivers in the Tongzhou district of Beijing and four soil samples(4, 5, 6, and 7) from the surface soils in the vicinity area of Tianjin near Bohai Bay, respectively. The isolated HA and NHC fractionsThe humic acid (HA) and nonhydrolyzable carbons (NHC) were isolated from three river sediment samples (1, 2, 3) from the rivers in the Tongzhou district of Beijing and four soil samples(4, 5, 6, and 7) from the surface soils in the vicinity area of Tianjin near Bohai Bay, respectively. The isolated HA and NHC fractions were also characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS), solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR), and Fourier transformed infrared spectroscopy (FTIR). The results showed that NHC had lower H/C and O/C atomic ratios than HA from the same source. The sum of surface O-containing groups accounted for 7.6%～10.7% and 40.9%～46.7% in NHC and HA samples, respectively. 13C NMR and FTIR spectra of the NHC samples revealed a large contribution of alkyl carbon and aryl carbon. In addition, the NHCs isolated from soils had higher content of aromatic carbon than the NHC form river sediments. Systematic characterization showed that the NHC samples were more condensed and hydrophobicity than the HA samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1194 (2013)
FTIR Spectra Study on the Swellbility and Controlled-Release Mechanism of Polyurethane Coated Urea
WU Shu, RU Tie-jun, and WANG Jin-ming
The nutrient release experiment of polyurethane coated urea (PCU) was carried out in pure water at 25 ℃. With the release of urea, the structural variation of polyurethane coating was investigated by Fourier transform infrared spectroscopy (FTIR), then a series of curves were collated and compared so as to better refleThe nutrient release experiment of polyurethane coated urea (PCU) was carried out in pure water at 25 ℃. With the release of urea, the structural variation of polyurethane coating was investigated by Fourier transform infrared spectroscopy (FTIR), then a series of curves were collated and compared so as to better reflect the relation between diffusion rate of urea and coating structure. It was found that when the nutrient was released by 50% wt, new absorption peaks at 3 435, 3 342, 1 671, 1 621, 1 448 and 1 159 cm-1 appear in the FTIR spectra of polyurethane coating, moreover, the height of these absorption peaks was increased gradually when the nutrient was released by 70% wt, more importantly, these new absorption peaks are consistent with the characteristic absorption peaks of urea fertilizer, the spectra of urea were mainly characterized by bands at 3 440, 3 346, 1 672, 1 621 and 1 461 cm-1. The results show that the IR spectra variation was caused by the content of urea, existing in the polyurethane coating, and was increased gradually, The more the urea content, the greater the swelling degree of the polyurethane coating. The swelling of polyurethane coating leads to the pores size change, and release rate is increased, so the “S” pattern curve of the nitrogen accumulative release is formed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1198 (2013)
Research on Discrimination of Cabbage and Weeds Based on Visible and Near-Infrared Spectrum Analysis
ZU Qin, ZHAO Chun-jiang, DENG Wei, and WANG Xiu
The automatic identification of weeds forms the basis for precision spraying of crops infest. The canopy spectral reflectance within the 350~2 500 nm band of two strains of cabbages and five kinds of weeds such as barnyard grass, setaria, crabgrass, goosegrass and pigweed was acquired by ASD spectrometer. According to The automatic identification of weeds forms the basis for precision spraying of crops infest. The canopy spectral reflectance within the 350~2 500 nm band of two strains of cabbages and five kinds of weeds such as barnyard grass, setaria, crabgrass, goosegrass and pigweed was acquired by ASD spectrometer. According to the spectral curve characteristics, the data in different bands were compressed with different levels to improve the operation efficiency. Firstly, the spectrum was denoised in accordance with the different order of multiple scattering correction (MSC) method and Savitzky-Golay(SG)convolution smoothing method set by different parameters, then the model was built by combining the principal component analysis (PCA) method to extract principal components, finally all kinds of plants were classified by using the soft independent modeling of class analogy (SIMCA) taxonomy and the classification results were compared. The tests results indicate that after the pretreatment of the spectral data with the method of the combination of MSC and SG set with 3rd order, 5th degree polynomial, 21 smoothing points, and the top 10 principal components extraction using PCA as a classification model input variable, 100% correct classification rate was achieved, and it is able to identify cabbage and several kinds of common weeds quickly and nondestructively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1202 (2013)
Study on Infrared Spectrum Change of Ganoderma Lucidum and Its Extracts
CHEN Zao-xin, XU Yong-qun, CHEN Xiao-kang, HUANG Dong-lan, and LU Wen-guan
From the determination of the infrared spectra of four substances (original ganoderma lucidum and ganoderma lucidum water extract, 95% ethanol extract and petroleum ether extract), it was found that the infrared spectrum can carry systematic chemical information and basically reflects the distribution of each componentFrom the determination of the infrared spectra of four substances (original ganoderma lucidum and ganoderma lucidum water extract, 95% ethanol extract and petroleum ether extract), it was found that the infrared spectrum can carry systematic chemical information and basically reflects the distribution of each component of the analyte. Ganoderma lucidum and its extracts can be distinguished according to the absorption peak area ratio of 3 416~3 279, 1 541 and 723 cm-1 to 2 935～2 852 cm-1. A method of calculating the information entropy of the sample set with Euclidean distance was proposed, the relationship between the information entropy and the amount of chemical information carried by the sample set was discussed, and the authors come to a conclusion that sample set of original ganoderma lucidum carry the most abundant chemical information. The infrared spectrum set of original ganoderma lucidum has better clustering effect on ganoderma atrum, Cyan ganoderma, ganoderma multiplicatum and ganoderma lucidum when making hierarchical cluster analysis of 4 sample set. The results show that infrared spectrum carries the chemical information of the material structure and closely relates to the chemical composition of the system. The higher the value of information entropy, the much richer the chemical information and the more the benefit for pattern recognition. This study has a guidance function to the construction of the sample set in pattern recognition..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1206 (2013)
Rapid Identification of Wolfberry Fruit of Different Geographic Regions with Sample Surface Near Infrared Spectra Combined with Multi-Class SVM
DU Min, GONG Ying, LIN Zhao-zhou, SHI Xin-yuan, HUA Guo-dong, and QIAO Yan-jiang
Portable near infrared spectrometer combined with multi-class support vector machines was used to discriminate wolfberry fruit of different geographic regions. Data pre-processing methods were explored before modeling with the identification rate as indicator. To eliminate the influence of sample subset partitioning onPortable near infrared spectrometer combined with multi-class support vector machines was used to discriminate wolfberry fruit of different geographic regions. Data pre-processing methods were explored before modeling with the identification rate as indicator. To eliminate the influence of sample subset partitioning on model performance, multiple modeling and predicting were conducted and the statistical result of identification rate was utilized to assess model performance of different acquisition sites. The results showed that SVM model with raw spectra after pretreatment of second derivative and Savitzky-Golay filter smoothing showed the best predicative ability. And the model of every acquisition site except for site 5 exhibited good stability and prediction ability and its median and average of identification rate of external validation were all greater than 97%. It was suggested that surface NIR spectra of wolfberry fruit was applicable to accurate identification of geographic region, and portable near infrared spectrometer could act as an effective means of monitoring the quality of Chinese herbal medicine in circulation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1211 (2013)
Dithiobis-Succinimidyl Propionate on Gold Island Films: Surface-Enhanced Infrared Absorption Spectroscopy Study
GUO Hao, DING Li, ZHANG Tian-jie, and MAO Yan-li
Dithiobis-succinimidyl propionate (DTSP), an important homobifunctional crosslinker, has been widely used for the covalent immobilization of proteins onto solid supports by amine coupling. In the present study, adsorption of DTSP on vacuum-deposited gold island films was analyzed by means of surface-enhanced infrared aDithiobis-succinimidyl propionate (DTSP), an important homobifunctional crosslinker, has been widely used for the covalent immobilization of proteins onto solid supports by amine coupling. In the present study, adsorption of DTSP on vacuum-deposited gold island films was analyzed by means of surface-enhanced infrared absorption spectroscopy (SEIRAS). For the sake of a reliable assignment of the vibrational spectra, IR intensity of the adsorption model of TSP on one gold surface was calculated using density functional theory (DFT) at the Beck’s three-parameter Lee-Yang-Parr (B3LYP) level with the LANL2DZ basis set. SEIRAS and multiple-angle-of-incidence polarization infrared reflection-absorption spectroscopy indicated that TSP is arranged orderly in a tilted fashion with a dihedral angle of 65 degrees between the plane of succinimidyl ring and the gold surface. The binding kinetics revealed that that the time constant of self-assembly of the TSP layer is 220 sec. Furthermore, the coupling process of amino-nitrilotriacetic acid (ANTA) with surface-bound TSP monolayer was monitored in situ by SEIRAS. Three negative bands observed at 1 807, 1 776, and 1 728 cm-1 respectively provided direct evidence for the reaction of the succinimidyl ester. The appearance of one intense band at 1 566 cm-1 gave a clear support for the presence of the cross-link between ANTA and TSP. We hope that the results in current investigation will contribute to the better understanding of properties of DTSP and related reactions at the molecular level..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1215 (2013)
Simultaneous Quantitative Determination of Multicomponents in Tablets Based on Terahertz Time-Domain Spectroscopy
CHEN Tao, LI Zhi, MO Wei, and HU Fang-rong
Terahertz time-domain spectroscopy (THz-TDS) combined with chemometric modeling methods was used to perform quantitative analysis of both active pharmaceutical ingredient (API) and excipient concentrations of multicomponent pharmaceutical mixtures. The THz spectra of ternary mixtures formulated with anhydrous theophyllTerahertz time-domain spectroscopy (THz-TDS) combined with chemometric modeling methods was used to perform quantitative analysis of both active pharmaceutical ingredient (API) and excipient concentrations of multicomponent pharmaceutical mixtures. The THz spectra of ternary mixtures formulated with anhydrous theophylline, lactose monohydrate, magnesium stearate and quaternary mixtures composed of acetaminophen, lactose monohydrate, microcrystalline cellulose and soluble starch were measured using THz-TDS. Two multivariate calibration methods, principal component regression (PCR) and partial least squares (PLS) regression, were employed to correlate THz absorbance spectra with the pharmaceutical tablet concentrations. Both API and excipient concentrations of mixtures were predicted simultaneously, and the PLS method provides better result than PCR method. The correlation coefficients of calibration (Rcal) and validation (Rval) for ternary mixtures’ components, anhydrous theophylline and lactose monohydrate, were all more than 0.98. The Rcal and Rval for quaternary mixtures’ components, acetaminophen, lactose monohydrate, microcrystalline cellulose and soluble starch, were all more than 0. 93, 0.98, 0.63 and 0.86, respectively. Experimental results show that THz-TDS combined with chemometrics is feasible in nondestructive quantitative analysis of multicomponent mixtures, and it can be widely applied in the fields of pharmaceutical analysis and others..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1220 (2013)
Near Infrared Spectroscopy and Multivariate Statistical Process Analysis for Real-Time Monitoring of Production Process
WANG Yi, MA Xiang, WEN Ya-dong, ZOU Quan, WANG Jun, TU Jia-run, CAI Wen-sheng, and SHAO Xue-guang
Near infrared diffusive reflectance spectroscopy has been applied in on-site or on-line analysis due to its characteristics of fastness, non-destruction and the feasibility for real complex sample analysis. The present work reported a real-time monitoring method for industrial production by using near infrared spectrosNear infrared diffusive reflectance spectroscopy has been applied in on-site or on-line analysis due to its characteristics of fastness, non-destruction and the feasibility for real complex sample analysis. The present work reported a real-time monitoring method for industrial production by using near infrared spectroscopic technique and multivariate statistical process analysis. In the method, the real-time near infrared spectra of the materials are collected on the production line, and then the evaluation of the production process can be achieved by a statistic Hotelling T2 calculated with the established model. In this work, principal component analysis (PCA) is adopted for building the model, and the statistic is calculated by projecting the real-time spectra onto the PCA model. With an application of the method in a practical production, it was demonstrated that a real-time evaluation of the variations in the production can be realized by investigating the changes in the statistic, and the comparison of the products in different batches can be achieved by further statistics of the statistic. Therefore, the proposed method may provide a practical way for quality insurance of production processes..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1226 (2013)
Terahertz-Band Study on Surface Enhanced Raman Scattering of Nanoparticle
WU Yu-deng, REN Guang-jun, HAO Yun, and YAO Jian-quan
Study on surface-enhanced Raman scattering in the terahertz-band proved in that the terahertz-band Raman enhancement also exists. By studing principles of electromagnetic enhancement of surface-enhanced Raman scattering, using the finite-difference time-domain method, the electromagnetic enhancement of surface enhancedStudy on surface-enhanced Raman scattering in the terahertz-band proved in that the terahertz-band Raman enhancement also exists. By studing principles of electromagnetic enhancement of surface-enhanced Raman scattering, using the finite-difference time-domain method, the electromagnetic enhancement of surface enhanced Raman scattering of nano-particles irradiated by terahertz-wave was simulated, and the enhancement effect of terahertz waves was analyzed. Simulation experiments show that using finite-difference time-domain method could obtain effectively accurate simulation result of nano-particle scattering, proving that for terahertz waves, surface-enhanced effects on the surface of the nano-particle also exist. The results for surface-enhanced Raman scattering extended from the visible and infrared to terahertz-band, and provide a basis for application of the combination of surface-enhanced Raman scattering and terahertz-wave..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1230 (2013)
Raman Spectroscopy Study of the Effect of H+ on the Oxygen Affinity Capacity of Hemoglobin
LIU Pei-pei, GUAN Xiao-yue, ZENG Chang-chun, NIE Guang, and LIU Song-hao
The hemoglobin was extracted from the blood which was provided by the healthy volunteers and the impact of the pH on hemoglobin oxygen binding capacity was studied with microscopic Raman spectroscopy. The results indicated that: under the excitation light of 514.5 nm, with the reducing of the oxygen partial pressure (PThe hemoglobin was extracted from the blood which was provided by the healthy volunteers and the impact of the pH on hemoglobin oxygen binding capacity was studied with microscopic Raman spectroscopy. The results indicated that: under the excitation light of 514.5 nm, with the reducing of the oxygen partial pressure (PO2), the Raman peak intensity at 1 375, 1 562, 1 585 and 1 638 cm-1 of the control hemoglobin (pH 7.4) reduced gradually, among which, the change of the 1 375 and 1 638 cm-1 were the most significant and had a good relevance with the PO2. The curves were plotted by regarding the PO2 as the x-axis and the Raman absolute intensity as the y-axis, and the relationship between hemoglobin Raman absolute intensity of the 1 375 and 1 638 cm-1and their related PO2 levels when the pH was 5.7, 7.4 and 8.0 respectively were analyzed. The data was well linear fitted and the fitting equation was obtained. The relationship of the slope (Raman intensity/PO2 level) among them were K8.0＞K7.4＞K5.7, indicating that the lower the pH, the easier the release of the oxygen molecules. It was showed that the Raman spectroscopy technique could be used to detect the oxygen binding rate of hemoglobin quantitatively, and the effect of the PH on oxygen binding state of hemoglobin could be observed, which could provide a new method and make a foundation for the monitoring of the PO2 levels in the blood, as well as the research on the regulatory factors of the blood oxygen affinity, such as H+ and CO2..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1234 (2013)
Application of the Raman Spectroscopy to the Study of Plant Cell Walls
MA Jing, MA Jian-feng, ZHANG Xun, and XU Feng
Due to the deficiency of energy supply and negative environmental impacts. Much attentions have been paid to agnicultural these lignocellulosic the replacement of fossil resources with and forestry biomass for the production of bio-fuels, chemicals and biomaterials on a global scale. Highly effective utilization of bioDue to the deficiency of energy supply and negative environmental impacts. Much attentions have been paid to agnicultural these lignocellulosic the replacement of fossil resources with and forestry biomass for the production of bio-fuels, chemicals and biomaterials on a global scale. Highly effective utilization of biomass is dependent on full understanding of their chemical composition and structural characteristics. A state-of-the-art Raman spectroscopy has evolved an important and nondestructive technique for plant research as information concerning histochemistry and structural characteristics of plant cell walls can be investigated in a nearly native state. In this paper, the principle of Raman imaging was introduced briefly. Meanwhile, the research progress in structural analysis of major components, micro-area distribution and molecular organization of the cellulose and lignin in the plant cell walls by Raman spectroscopy was summarized. The aim of the review is to promote the application of Raman spectroscopy to the study of plant cell walls..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1239 (2013)
Study on the CNT Sensor for Strain Measurement and Its Control Method of Raman Polarization
LI Shi-lei, QIU Wei, KANG Yi-lan, LEI Zhen-kun, LI Qiu, DENG Wei-lin, and GAO Di
The present paper studied the methodology of carbon nanotube (CNT) sensor applicable for the strain measurement in microscale. Based on the varieties of polarization configurations of the Raman spectrometers, a series of analytic expressions of CNT sensor were derived by applying the Raman properties of the CNT, such aThe present paper studied the methodology of carbon nanotube (CNT) sensor applicable for the strain measurement in microscale. Based on the varieties of polarization configurations of the Raman spectrometers, a series of analytic expressions of CNT sensor were derived by applying the Raman properties of the CNT, such as the strain sensitivity and the polarization selectivity. From the viewpoint of metrology, the sensoring relationships corresponding to different polarization configurations were compared and contrasted with one another, which educed that the “bipolar homology” type is most suitable for the strain measurement where both the incident and scattered lights are continuously controllable and always remain parallel to each other. A new easy-realized control method for this configuration is introduced. The experiments proved that the method presented in this paper can effectively measure the in-plane strain components in microscale by polarized micro-Raman spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1244 (2013)
The Investigation of Humic Acid by Surface-Enhanced Raman Spectroscopy
ZHANG Wen-juan, LI Ying, GUO Jin-jia, XIAO Qiong, and YU Li
Humic acid (HA), which are organic compounds widely existing in the oceans, rivers and soil, has important significance for the enviro nmental monitoring of soil and water. In this paper, ai ming at the problem of Surface-enhanced Raman Spectroscopy (SERS) applying for HA detection in water, the characteristics of the Humic acid (HA), which are organic compounds widely existing in the oceans, rivers and soil, has important significance for the enviro nmental monitoring of soil and water. In this paper, ai ming at the problem of Surface-enhanced Raman Spectroscopy (SERS) applying for HA detection in water, the characteristics of the humic acid on silver colloids was studied by means of SERS. The influence of laser irradiation time, HA concentrations and pH value on the surface-enhanced effects of HA were investigated. The experimental results show that the SERS spectra of HA is ideal when the laser irradiation time between 20～30 min. The SERS of different HA concentrations was detected. It was found that the relative intensity at 1 379 cm-1 increased as a linear function of the concentration of HA with correlation coefficient R2 of 0.993. The SERS of HA was found to be very sensitive to pH, the SERS spectra of HA was very weak at neutral pH, but at acidic pH and alkaline pH a remarkable increase of SERS intensity occurred. The SERS of HA in running water was detected too. The experimental results show that it is feasible to detect HA in natural water by means of surface-enhanced Raman spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1249 (2013)
Feasibility Reaserch on Using Raman Spectroscopy with PLS for the Quantitative Detection of Cholesterol Content in Serum
DONG Hai-sheng, ZHANG Li-fen, ZHONG Yue, HUANG Jian-ying, and CHEN Bin
Taking the serum obtained from daily clinical inspection as study object, the Raman spectra were collected with the range of 250 to 2 400 cm-1. Taking the serum cholesterol content determined by traditional clinical biochemical method as contrast, together with combination of PLS, we established a Raman spectroscopy quTaking the serum obtained from daily clinical inspection as study object, the Raman spectra were collected with the range of 250 to 2 400 cm-1. Taking the serum cholesterol content determined by traditional clinical biochemical method as contrast, together with combination of PLS, we established a Raman spectroscopy quantitative models for cholesterol content in serum. The experimental results show that Raman spectroscopy displacement could reflect certain chemical group in organic compound. The correction model of cholesterol content in serum was established with the coefficient R=0.909 6, cross-validation calibration standard deviation (RMSECV) of 0.24, standard error of prediction of test set (RMSEP) was 0.69, and coefficient (R) is 0.926 2. The results showed that application of Raman spectroscopy combined with chemometrics in the rapid noninvasive detection of serum cholesterol content is feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1253 (2013)
Analytical Method for On-Site Test of Drug Precursor Chemicals
YOU Xiao-ming, HONG Li-jun, LI Zhi-hao, and SHU Tian-min
Thirteen kinds of common drug precursor chemicals were detected on the spot by transportable Raman spectrometer independently researched and developed. Changing analysis methods, such as the focal position of the instrument, analysis time, external light source, sample containers and the concentration of the analyte, tThirteen kinds of common drug precursor chemicals were detected on the spot by transportable Raman spectrometer independently researched and developed. Changing analysis methods, such as the focal position of the instrument, analysis time, external light source, sample containers and the concentration of the analyte, the high quality Raman spectrums were obtained. The study shows that analysis method can be optimized to improve the detection efficiency, LOD(limit of detection)of 1-phenyl-2-acetone, toluene and chloroform was recorded for lower concentrations and the component contents of the mixture have a significant impact on the test results. Selecting the appropriate instrument conditions can be more effective and fast screening of precursor chemicals on site to provide help for those who are engaged in the anti-drug work．.
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1257 (2013)
Studies on Toxicity of Four Kinds of Heavy Metals in Water by Synchronous-Scan Fluorescence
DUAN Jing-bo, LIU Wen-qing, ZHANG Yu-jun*, ZHAO Nan-jing, WANG Zhi-gang, YIN Gao-fang, FANG Li, and LIU Jing
Spectrofluorometry of chlorella pyrenoidosa was studied by three dimensional excitation-emission (3DEEM) fluorescence spectroscopy and synchronous scan fluorescence spectroscopy with Δλ=20 nm in the stress of Hg2+, Cd2+, Cu2+ and Zn2+. The conclusion from two kinds of Spectrofluorometry was the same: after 96h stress bSpectrofluorometry of chlorella pyrenoidosa was studied by three dimensional excitation-emission (3DEEM) fluorescence spectroscopy and synchronous scan fluorescence spectroscopy with Δλ=20 nm in the stress of Hg2+, Cd2+, Cu2+ and Zn2+. The conclusion from two kinds of Spectrofluorometry was the same: after 96h stress by heavy metals, the maximum fluorescence values reduced obviously, chlorophyll-a and chlorophyll-b in the photosynthetic system were seriously damaged by heavy metal. Further analysis of the correlations between heavy metal concentration and fluorescence quenching efficiency I0/I can conclude that the toxicity of heavy metal and the fluorescence quenching efficiency I0/I were positively correlated, and they all increased with the heavy metal concentration and stress time. For one kind of heavy metals, synchronous scan fluorometry is a sensitive method for its toxicity assessment. Compared to 3DEEM fluorescence spectroscopy, synchronous scan fluorescence spectroscopy is less time consuming and of higher selectivity. It is suitable to assess the toxicity of pollutions in water..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1262 (2013)
Study of CdTe Quantum Dots as Fluorescence Probe to Detect Trace Amount of Pb2+
DU Bao-an, LIU Cheng, CAO Yu-hong, GAO Lu, and ZHAO Xue-yuan
The surface modified quantum dots (QDs) as fluorescence probe to quantitatively detect the Pb2+ in water phase was studied in the paper. Using the mercaptopropionic acid (MPA) as the stabilizer, the CdTe quantum dots were synthesized in water phase. Based on the quenching effect of the Pb2+ on the QDs fluorescence, theThe surface modified quantum dots (QDs) as fluorescence probe to quantitatively detect the Pb2+ in water phase was studied in the paper. Using the mercaptopropionic acid (MPA) as the stabilizer, the CdTe quantum dots were synthesized in water phase. Based on the quenching effect of the Pb2+ on the QDs fluorescence, the method for detecting trace Pb2+ using QDs as probe was established. The results showed that the relationship between the Pb2+ concentration and the quenching intensity of the QDs (ΔF) while the Pb2+ concentration ranged from 1.0×10-8 to 1.0×10-6 mol·L-1 was fairly linear, and the correlation coefficient was 0.997 2. The detection limit was 9.3×10-10 mol·L-1. The RSD was 5.9%, and the recovery rate was between 86% and 110%. The study of the interference of the metal ions showed that the method was highly selective..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1266 (2013)
A TDDFT Study on the Photophysical Mechanism of Optical Quenching of a New Type Fluorescent Probe Molecule
DAI Yu-mei, LI Fu-jun, MIAO Chun-chao, and HU Xiao-jun
3-hydroxyl flavone (3-HF), a typical representative of the second generation new fluorescence molecular probe, was studied by high-accuracy quantum chemical methods, density functional theory (DFT), in the present paper. The photo-physics mechanism of 3-HF as fluorescence molecular probe was studied by the calculation 3-hydroxyl flavone (3-HF), a typical representative of the second generation new fluorescence molecular probe, was studied by high-accuracy quantum chemical methods, density functional theory (DFT), in the present paper. The photo-physics mechanism of 3-HF as fluorescence molecular probe was studied by the calculation of the optimum geometry structure, charge population and excitation spectrum, in the ideal condition. Then the calculation results were analyzed, and the photo-physics looping graph was plotted for the elucidation of the mechanism. Compared with the experiments, the geometry structure obtained by our calculation is in good agreement, and the errors in the calculated excitation spectrum are in a reasonable limitation. As in this paper, it is only a tentative research work in the field of molecule fluorescence probe with the method of quantum chemistry calculation, and we hope that it could provide systematically valuable theoretical reference in this field in the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1270 (2013)
Spectroscopic Evaluation of Effects of Heat Treatments on the Structures and Emulsifying Properties of Caseins
ZHANG Hao, WANG Peng-jie, LEI Xin-gen, YANG Hong-ju, ZHANG Lu-da, REN Fa-zheng, and ZHENG Li-min
The effects of heat treatment (heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy. Heat treatment from 60 to 100 ℃ resulted in an increase in their fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying activity index, but deThe effects of heat treatment (heating temperature and pH) on the structures and emulsifying properties of caseins were systematically studied by spectroscopy. Heat treatment from 60 to 100 ℃ resulted in an increase in their fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying activity index, but decreased the size polydispersity of caseins. In the pH range of 5.5 to 7.0, the fluorescence intensity, hydrodynamic diameter, turbidity and emulsifying properties decreased with increased heating pH, but the size polydispersity of caseins increased with increased pH. The relationship between the surface fluorescence intensity and emulsifying activity was also investigated, revealing a correlation coefficient of 0.90. These results suggested that heat treatment could be used to modify the structures and emulsifying properties of caseins by appropriately selecting heating conditions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1275 (2013)
Retrieval of Atmospheric CO2 from Ground-Based High Resolution FTS Spectra
WU Jun, FANG Yong-hua, YE han-han, WANG Xian-hua, and JIANG Xin-hua
Atmospheric carbon dioxide is a key greenhouse gas. Global monitoring of carbon dioxide would be helpful to improving the understanding of climate change. Ground-based observations usually have higher resolution and signal-to-noise ratio and more known parameters than satellite-based observations, which make it easier Atmospheric carbon dioxide is a key greenhouse gas. Global monitoring of carbon dioxide would be helpful to improving the understanding of climate change. Ground-based observations usually have higher resolution and signal-to-noise ratio and more known parameters than satellite-based observations, which make it easier to achieve a better retrieval precision. Ground-based retrieval method could be extended to satellite scenarios, and it could also provide validation for satellite data. The main procedure of the retrieval method was established, and this procedure was validated by simulated retrieval. It was proved that the method could get reasonable results under certain system errors. The retrieval of ground-based FTS spectra showed that this method has a potential to obtain atmospheric carbon dioxide column information..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1281 (2013)
An Information Extraction Method of Spectral Images Based on 3D Spectral Angle Statistics
FENG Wei-yi, CHEN Qian, HE Wei-ji, GU Guo-hua, and MIAO Zhuang
A novel information extraction method of spectral images based on 3D spectral angle statistics is proposed. By computing the spectral angle between adjacent pixels of the image in the horizontal, vertical and diagonal direction respectively, a 3D information statistical model was then constructed. This model reflects tA novel information extraction method of spectral images based on 3D spectral angle statistics is proposed. By computing the spectral angle between adjacent pixels of the image in the horizontal, vertical and diagonal direction respectively, a 3D information statistical model was then constructed. This model reflects the similarity between adjacent pixels which represent some kind of materials. Uniform areas and edge information of the same material, which will be used for the training sample collection in supervised classification, can be extracted from the image if different threshold values are set and slices are extracted from different axes in the statistical model. Compared with the traditional statistical tools, such as the histogram and scatter diagram, this statistical method has higher robustness and reliability. And it can obtain more information extracted from the spectral images..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1285 (2013)
Characteristics of U(Ⅵ) Biosorption by Biological Adsorbent of Platanus Leaves
NIE Xiao-qin, DONG Fa-qin, LIU Ming-xue, LIU Ning, ZHANG Wei, and YANG Xue-ying
The platanus leaves were used as adsorbent to study uranium removal efficiency from aqueous solution on the basis of adsorption kinetics and isotherm equations. Static adsorption affected by initial pH values and contact time was analyzed, and surface characteristics of platanus leaves and uranium removal mechanism werThe platanus leaves were used as adsorbent to study uranium removal efficiency from aqueous solution on the basis of adsorption kinetics and isotherm equations. Static adsorption affected by initial pH values and contact time was analyzed, and surface characteristics of platanus leaves and uranium removal mechanism were investigated with the help of SEM, FTIR, XRD and XRF. The adsorption process fits pseudo-second-order kinetic model and Freundlich isotherm equation, and the maximum adsorption capacity for uranium was 19.68 mg·g-1. Results showed that hydroxyl groups, amides II belt and carboxyl active functional groups were important for uranium removal. Structure characteristic adsorption band of cellulose was found in XRD spectra, uranium was detected, and also Ca and Na elements of the content increased. Mg element content relative decrease was found on platanus leaves after adsorption by XRF, and it proved the reaction feasibility. Speculation for the behavior of uranium adsorption by platanus leaves was both physical adsorption and chemical adsorption, exhibiting joint action of electrostatic attraction, redox reaction, chelating ligand and ion exchange..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1290 (2013)
Preparation and Properties of P-Type Cd1-xZnxTe Thin Films
ZHAO Yu, JIANG Hong-chao, WU Li-li*, FENG Liang-huan, ZENG Guang-gen, WANG Wen-wu, ZHANG Jing-quan, and LI Wei
Cd1-xZnxTe∶Cu Thin films were prepared by co-evaporation method. X-ray Fluorescence Spectrometry (XRF), scanning electron microscope(SEM), UV-Vis transmission spectra, thermal probe, four-probe method, step profiler and X-ray diffractometer (XRD) were used to investigate the composition, structure, morphology, optical Cd1-xZnxTe∶Cu Thin films were prepared by co-evaporation method. X-ray Fluorescence Spectrometry (XRF), scanning electron microscope(SEM), UV-Vis transmission spectra, thermal probe, four-probe method, step profiler and X-ray diffractometer (XRD) were used to investigate the composition, structure, morphology, optical and electrical properties of Cd1-xZnxTe∶Cu thin films with different doping concentration. The results show that the resistivity of 10% copper doped Cd1-xZnxTe films increased several magnitude and the conductive type changed from p-type to n-type after annealing. The 20% cu-doped Cd1-xZnxTe films had not obvious change in conductive type and electrical resistivity after annealing and they exhibit good surface morphology. The transmissivity of 30% cu-doped Cd1-xZnxTe films decreased seriously below 10% after annealing, which indicate that they are not suitable to be the top cell materials in tandem structure. The 20% and 30% cu-doped Cd1-xZnxTe films were both p-type conductivity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1295 (2013)
Synthesis of Folate Receptor-Targeted Nanoprobe for Detection of Cancer Cells and Its Spectral Analysis
YAO Cui-ping1, WANG Jing, YANG Yang, DONG Yan-hua, XUE Yang, MEI Jian-sheng, ZENG Wei-hui, and ZHANG Zhen-xi
Folate receptor (FR) is particularly upregulated in many epithelial cancer cells membrane and limited distribution is found in normal tissues. In the present work, the folic acid protected gold nanoparticles (FA-GNPs) were synthesized by a simple and quick method, in which chloroauric acid (HAuCl4) was reduced by sodiuFolate receptor (FR) is particularly upregulated in many epithelial cancer cells membrane and limited distribution is found in normal tissues. In the present work, the folic acid protected gold nanoparticles (FA-GNPs) were synthesized by a simple and quick method, in which chloroauric acid (HAuCl4) was reduced by sodium borohydride (NaBH4) in the presence of FA is used as stabilizer. UV-Visible spectroscopy and transmission electron microscopy (TEM) were used to characterize the shape and size distribution of the produced FA-GNPs. X-ray photoelectron spectroscopy and cell experiment were employed to confirm the immobilization of FA and GNPs. The results showed that FA-GNPs have a good size distribution in the 3~5 nm diameter range. Moreover, it is very stable even in solution with high concentration of salt (up to 3.5% NaCl), and even high speed centrifuges of 25 000 r·min-1 could not cause aggregation. The nanoparticles could be used to detect cancer cells..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1299 (2013)
Preparation, Characterization and Photocatalysis of Bi2WO6 Nanocrystals
XIA Jia-wei, ZHANG Yue, LU Lei, and HAN Qiao-feng
In the present study, bismuth tungstate(Bi2WO6) nanocrystals were prepared by the hydrothermal method using bismuth nitrate (Bi(NO3)3·5H2O) and sodium tungstate (Na2WO4·2H2O) as raw materials at 150 ℃ for 24 h. The powder X-ray diffraction (XRD) pattern shows that the Bi2WO6 nanocrystals belong to the orthorhIn the present study, bismuth tungstate(Bi2WO6) nanocrystals were prepared by the hydrothermal method using bismuth nitrate (Bi(NO3)3·5H2O) and sodium tungstate (Na2WO4·2H2O) as raw materials at 150 ℃ for 24 h. The powder X-ray diffraction (XRD) pattern shows that the Bi2WO6 nanocrystals belong to the orthorhombic phase with calculated lattice constants a=5.457 , b=16.435 and c=5.438 . The X-ray photoelectron spectra (XPS) indicate that the obtained Bi2WO6 was pure. The photocatalytic activity of the nanocrystal prepared by using water, N, N-dimethyl formamide (DMF) and ethylene glycol (EG) as the solvent respectively were studied for the degradation of rhodamine B under visible light irradiation. The results show that Bi2WO6 sample obtained in EG has the best photocatalytic activity mainly owing to good dispersion, small particle size and broader spectrum response for visible light. In addition, the influence of pH and surfactant on the Bi2WO6 photocatalytic activity was also studied. The results show that Bi2WO6 sample has better photocatalytic activity when prepared at 150 ℃ and pH 1.0 with sodium dodecylsulfate (SDS) as the surfactant. The photoluminescence (PL) spectra of the prepared Bi2WO6 reveal that the recombination of photo-generated electrons and holes was inhibited over Bi2WO6 prepared with SDS and thus its photocatalytic ability was enhanced..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1304 (2013)
A New Tunable SOI Micro-Ring Resonator with Three Coupling Points
LI Zhi-quan, ZHANG Xin, SUN Yu-chao, LI Xiao-yun, and BAI Chun-lei
A new structure of tunable single micro-ring with three coupling points was proposed in the present paper based on the theory of coupled modes and transmission matrix. Also, the output optical spectrum was simulated by the aid of Matlab. In this new structure, we use silicon-on-insulator (SOI) as its material, so the oA new structure of tunable single micro-ring with three coupling points was proposed in the present paper based on the theory of coupled modes and transmission matrix. Also, the output optical spectrum was simulated by the aid of Matlab. In this new structure, we use silicon-on-insulator (SOI) as its material, so the output optical spectrum can be tuned when the length or temperature is changed in feedback waveguide. According to the outcome of simulation, when the coupling coefficient k is 0.018, the free spectral range (FSR) approaches 43.8 nm and the quality factor is 1.25×105. This resonator not only has narrow bandwidth, high quality factor and large FSR, but also can achieve the tunable output optical spectrum through modulating the properties of feedback waveguide. The corresponding curve was presented in this paper as well..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1309 (2013)
Band Depth Analysis and Partial Least Square Regression Based Winter Wheat Biomass Estimation Using Hyperspectral Measurements
FU Yuan-yuan, WANG Ji-hua, YANG Gui-jun, SONG Xiao-yu, XU Xin-gang, and FENG Hai-kuan
The major limitation of using existing vegetation indices for crop biomass estimation is that it approaches a saturation level asymptotically for a certain range of biomass. In order to resolve this problem, band depth analysis and partial least square regression (PLSR) were combined to establish winter wheat biomass eThe major limitation of using existing vegetation indices for crop biomass estimation is that it approaches a saturation level asymptotically for a certain range of biomass. In order to resolve this problem, band depth analysis and partial least square regression (PLSR) were combined to establish winter wheat biomass estimation model in the present study. The models based on the combination of band depth analysis and PLSR were compared with the models based on common vegetation indexes from the point of view of estimation accuracy, subsequently. Band depth analysis was conducted in the visible spectral domain (550~750 nm). Band depth, band depth ratio (BDR), normalized band depth index, and band depth normalized to area were utilized to represent band depth information. Among the calibrated estimation models, the models based on the combination of band depth analysis and PLSR reached higher accuracy than those based on the vegetation indices. Among them, the combination of BDR and PLSR got the highest accuracy (R2=0.792, RMSE=0.164 kg·m-2). The results indicated that the combination of band depth analysis and PLSR could well overcome the saturation problem and improve the biomass estimation accuracy when winter wheat biomass is large..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1315 (2013)
Evaluation on the Atmospheric Correction Methods for Water Color Remote Sensing by Using HJ-1A/1B CCD Image-Taking Poyang Lake in China as a Case
ZENG Qun, ZHAO Yue, TIAN Li-qiao, and CHEN Xiao-ling
HJ-1A/1B satellite CCD images have higher spatial and temporal resolution, making them of great potential in quantitatively monitoring the water quality of inland lakes. However, the atmospheric correction of the images restricts their application. Therefore, taking Poyang Lake, the biggest freshwater lake in China as HJ-1A/1B satellite CCD images have higher spatial and temporal resolution, making them of great potential in quantitatively monitoring the water quality of inland lakes. However, the atmospheric correction of the images restricts their application. Therefore, taking Poyang Lake, the biggest freshwater lake in China as study area , and using the in-situ data collected in 2009 and 2011, this paper compares the atmospheric correction results done by the four methods: FLAASH, 6S, COST and QUAC, and analyzes the influence of these atmospheric correction methods on the inversion accuracy of the total suspended sediments (TSS) concentration. The results indicate: (1) the band 1 (blue band) of HJ-1A/1B CCD satellite images should be recalibrated while being applied into water quality remote sensing. The accuracy of atmospheric correction done from band 2 (green band) and band 3 (red band) is higher than that of others , especially that of the correction done by FLAASH, 6S and COST is much higher while that of correction done by QUAC is lower. So the algorithms of QUAC should be pointedly improved. (2) The ratios done from band 2 and band 3 have a good match with in-situ data , with an average relative error of 8.2%, 9.5%, 7.6% and 11.6% respectively for FLAASH, 6S, COST and QUAC. Therefore, it would be better to use the ratio done from band 2 and band 3 as inversion factors in Poyang Lake. (3) It is found that the accuracy of directly building models by using the four atmospheric corrected results and the TSS concentration is higher than the models built by the in-situ remote sensing reflectance and the TSS concentration. The accuracy of the TSS concentration inverted by FLAASH, 6S and COST is much high with an average error of only 10.0%, 10.2% and 8.0% respectively, while the error inverted by QUAC is a little bit higher of being 18.6%. So it is suggested to build model with atmospheric correction results and the TSS concentration data, because it can avoid the cumulate error resulted from modeling by using the in-situ spectrum data. (4) Under a low requested situation, these four atmospheric correction algorithms can all be adopted; otherwise, the COST should be used in the case of lacking supplementary information..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1320 (2013)
Determination of Recombinant Hirudin in Urine of Rat by Spectrophotometric Method
JIANG Su-yun, JIAO Jian, LU Jun, XU Yong-ping, and DOU Gui-fang
To develop a spectrophotometric method for determining the concentration of recombinant hirudin (rH) in urine of rats. rH concentration was determined based on the rH inhibility to thrombin which hydrolyzed the Chromozym TH TH chromogenic substrate to form the specific pNA absorbed at 405nm. The standard rH in rat urinTo develop a spectrophotometric method for determining the concentration of recombinant hirudin (rH) in urine of rats. rH concentration was determined based on the rH inhibility to thrombin which hydrolyzed the Chromozym TH TH chromogenic substrate to form the specific pNA absorbed at 405nm. The standard rH in rat urine was determined by the spectrophotometric method at concentration of 6.25 to 75 ng·mL-1 with day and intra-day RSD <10%, method recoveries of >95% and the dilution recoveries of >93%. The rH samples of rat urines which iv dose of 0.5, 1.0, and 2.0 mg·kg-1 were collected and analyzed by the CSA method. Their cumulative excretion rH at 0～12 hr were (116.850±57.160), (235.544±39.375) and (474.986±85.426) μg·kg-1. The calculated cumulative excretion rate of three doses is about 23% which indicates that the rH was eliminated in the way of a linear kinetics in rats. The rH content in rat urine could be measured by the spectrophotometric method accurately, reliably and sensitively for the rH urinary excretion dynamics study..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1327 (2013)
Seasonal Changes in Copper and Cobalt Concentrations of Pinus nigra L., Cedrus libani and Cupressus arizonica Leaves to Monitor the Effects of Pollution in Elazig (Turkey)
Nagihan M Karaaslan, and Mehmet Yaman
The aim of this study is to examine seasonal changes in Cu and Co concentrations of three plant species for monitoring the effects of pollution in Elazig, Turkey. For this purpose, the leaves of the Pinus nigra L., Cedrus libani and Cupressus arizonica together with soil samples were collected from different points depThe aim of this study is to examine seasonal changes in Cu and Co concentrations of three plant species for monitoring the effects of pollution in Elazig, Turkey. For this purpose, the leaves of the Pinus nigra L., Cedrus libani and Cupressus arizonica together with soil samples were collected from different points depending on traffic intensity, nearness the city center and cement factory as well as control location during different months of the year. Flame atomic absorption spectrophotometer (FAAS) was used for measurement of the metals in clear digests after the dry ashing method. Copper and Co concentrations were in the ranges from 1.3 to 2.6 mg·kg-1 and
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1331 (2013)
Effect of Ultrasonic Cavitation on ICP Source Radiation Intensity
CHEN Jin-zhong, WEN Nuan, SUN Jiang, LI Xu, and YANG Bao-zhu
In order to increase the intensity of inductively coupled plasma radiation and reduce the detection limit of analysis, the experiment studied on the change of surface tension and viscosity of the water samples which were processed by the ultrasonic cavitation, meanwhile the influence of cavitation effect to samples’ spIn order to increase the intensity of inductively coupled plasma radiation and reduce the detection limit of analysis, the experiment studied on the change of surface tension and viscosity of the water samples which were processed by the ultrasonic cavitation, meanwhile the influence of cavitation effect to samples’ spectral intensity and signal-to-background ratio was researched. The experimental results showed that the surface tension and viscosity of sample solution initially decreased and then increased as the ultrasonic power and cavitation time monotonously increased, and the minimum value could be achieved at the ultrasonic power of 50W and the cavitation time of 15 minutes. Under the best experiment condition (the ultrasonic power of 50W and the cavitation time of 15 min), the results revealed that the spectral lines intensity of element Al, Cd, Mn, Ni, Pb and Zn were increased around 56.73％, 57.23％, 44.57％, 43.20%, 39.04％ and 40.19％ than that without cavitation treatment, spectral signal-background ratio increased about 61.54％, 64.86％, 40.95％, 52.27%, 37.84％ and 40.84％, respectively. Thus it can be seen that cavitation-processed water solution can improve the quality of Inductively Coupled Plasma-atomic emission spectrum..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1338 (2013)
High-Precision In Situ Analysis of the Lead Isotopic Composition in Copper Using Femtosecond Laser Ablation MC-ICP-MS and the Application in Ancient Coins
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the present study we set up a femtosecond laser ablation MC-ICP-MS method for lead isotopic analysis. Pb isotopic composition of fifteen copper (brass, bronze) standard samples from the National Institute of Standards Material were analyzed using the solution method (MC-ICP-MS) and laser method (fLA-MC-ICPMS) respecIn the present study we set up a femtosecond laser ablation MC-ICP-MS method for lead isotopic analysis. Pb isotopic composition of fifteen copper (brass, bronze) standard samples from the National Institute of Standards Material were analyzed using the solution method (MC-ICP-MS) and laser method (fLA-MC-ICPMS) respectively, the results showed that the Pb isotopic composition in CuPb12 (GBW02137) is very homogeneous, and can be used as external reference material for Pb isotopic in situ analysis. On CuPb12 112 fLA-MC-ICPMS Pb isotope analysis, the weighted average values of the Pb isotopic ratio are in good agreement with the results analyzed by bulk solution method within 2σ error, the internal precision RSEs of the 208Pb/204Pb ratio and 207Pb/206Pb ratio are less than 90 and 40 ppm respectively, and the external precision RSDs of them are less than 60 and 30 ppm respectively. Pb isotope of thirteen ancient bronze coins was analyzed via fLA-MC-ICPMS, the results showed that the Pb isotopic composition of ancient coins of different dynasties is significantly different, and not all the Pb isotopic compositions in the coins even from the same dynasty are in agreement with each other..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1342 (2013)
Determination of Impurity Elements in the Positive Electrode Material LiMn2O4 by Inductively Coupled Plasma Mass Spectrometry
ZHU Qian-hua
Samples of LiMn2O4 were digested by microwave digestion, and impurity elements amounts of Na, Mg, Al, K, Ca, Ti, Cr, Fe, Cu, Zn, As, Ag, Cd and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation was achieved by digestion with HNO3+HCl in a closed-vessel mSamples of LiMn2O4 were digested by microwave digestion, and impurity elements amounts of Na, Mg, Al, K, Ca, Ti, Cr, Fe, Cu, Zn, As, Ag, Cd and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). Sample preparation was achieved by digestion with HNO3+HCl in a closed-vessel microwave system. The effects of mass spectrum interference were studied. Sc, Rh and Tl as internal standard elements were used to compensate matrix effect and signal drift. Under the optimal conditions, the detection limits of the 14 elements are in the range of 0.007～0.209 μg·L-1. The recovery was 92.66%～108.34% by adding standard recovery experiment, and the relative standard deviation (RSD) was less than 4.80% for all the elements. This method was simple, sensitive and precise, which could satisfy the sample examination request and provide scientific rationale for determining impurity elements of LiMn2O4..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1350 (2013)
Study on the Determination of Trace Elements in Bitter Almond by Inductively Coupled Plasma Mass Spectrometry
LIU Hong-wei, XIE Hua-lin, and NIE Xi-du
Samples of bitter almond were digested by microwave digestion, and trace elements amounts of B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Ba and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). HNO3+H2O2 was used to achieve the complSamples of bitter almond were digested by microwave digestion, and trace elements amounts of B, Na, Mg, Al, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Ba and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). HNO3+H2O2 was used to achieve the complete decomposition of the organic matrix in a closed-vessel microwave oven. The working parameters of the instrument were optimized. The results showed that the relative standard deviation (RSD) was less than 4.79% for all the elements, and the recovery was 90.00%～109.30% by adding standard recovery experiment. This method was simple, sensitive and precise and can perform simultaneous multi-elements determination for bitter almond, which could satisfy the sample examination request and provide scientific rationale for determining inorganic elements in bitter almond..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1354 (2013)
Determination of Trace Lead in Water and Milk Tea Powder Samples with Organic Coprecipitation-Flame Atomic Absorption Spectrometric
LIN Jian-mei, YAO Jun-xue, and ZHAO Wen-yan
A method was proposed for the determination of trace lead with flame atomic absorption spectrometry after preconcentration of lead by rapid coprecipitation technique with PAR-Fe(Ⅲ) at pH 6.0. The analytical parameters including pH, amount of iron(Ⅲ), amount of reagent, the standing time of the precipitate, etc., were eA method was proposed for the determination of trace lead with flame atomic absorption spectrometry after preconcentration of lead by rapid coprecipitation technique with PAR-Fe(Ⅲ) at pH 6.0. The analytical parameters including pH, amount of iron(Ⅲ), amount of reagent, the standing time of the precipitate, etc., were examined. The detection limits (DL) were found to be 18.7 μg·L-1 for Pb(Ⅱ). In analysis of lake water and the milk tea powder samples, RSD’s and the standard addition recovery of this method were in the ranges of 1.03%～2.24% and 94.2%～98.3% respectively. The effect of matrix can be overcome by the method and the results are satisfyiog. The method shows good application prospect in the determination of trace lead owing to its rapidness and reproducibility..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1357 (2013)
Near Infrared Distance Sensing Method for Chang’E-3 Alpha Particle X-Ray Spectrometer
LIANG Xiao-hua, WU Ming-ye, WANG Huan-yu, PENG Wen-xi, ZHANG Cheng-mo, CUI Xing-zhu, WANG Jin-zhou, ZHANG Jia-yu, YANG Jia-wei, FAN Rui-rui, GAO Min, LIU Ya-qing, ZHANG Fei, DONG Yi-fan, and GUO Dong-ya
Alpha particle X-ray spectrometer (APXS) is one of the payloads of Chang’E-3 lunar rover, the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present papAlpha particle X-ray spectrometer (APXS) is one of the payloads of Chang’E-3 lunar rover, the scientific objective of which is in-situ observation and off-line analysis of lunar regolith and rock. Distance measurement is one of the important functions for APXS to perform effective detection on the moon. The present paper will first give a brief introduction to APXS, and then analyze the specific requirements and constraints to realize distance measurement, at last present a new near infrared distance sensing algorithm by using the inflection point of response curve. The theoretical analysis and the experiment results verify the feasibility of this algorithm. Although the theoretical analysis shows that this method is not sensitive to the operating temperature and reflectance of the lunar surface, the solar infrared radiant intensity may make photosensor saturation. The solutions are reducing the gain of device and avoiding direct exposure to sun light..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1360 (2013)
Discussion on Diagenesis of Xilingang Pluton—Constrained by X-Ray Fluorescence Spectroscopy, Plasma Mass Spectrometry and Raman Spectroscopy
TANG Yu-kun, CHEN Guo-neng, ZHANG Ke, and HUANG Hai-hua
The results on Xilingang pluton, mainly consisting of red beds, granites containing numerous debris of red beds and granites, obtained by X-ray fluorescence spectroscopy, plasma mass spectrometry and Raman spectroscopy show: (1) Xilingang pluton from red beds, granites containing numerous debris of red beds to granitesThe results on Xilingang pluton, mainly consisting of red beds, granites containing numerous debris of red beds and granites, obtained by X-ray fluorescence spectroscopy, plasma mass spectrometry and Raman spectroscopy show: (1) Xilingang pluton from red beds, granites containing numerous debris of red beds to granites has obvious characteristics of decreasing silicon and alkali content, and rising ignition loss, dark mineral content and oxidation index; (2) Chondrite-normalized REE distribution curves and primitive mantle-normalized spider diagram for trace elements of redbed, granites containing numerous debris of red beds and granites have a good consistency, the distribution characteristics of elements are similar to Nanling transformation-type granite; (3) The value of Raman spectrogram characteristic peak of quartz crystal in Xilingang granite decreased from the center of quartz crystal, and FWHM is steady. According to the above, the authors believe that Xilingang granite formed was related to in-situ melting of red beds and underlying strata and magma consolidation. Volatile components were discharged continuously, and oxidation index decreased gradually in the melting process. In the process of diagenesis, the top of pluton tend to be an ongoing silicon and alkali increase, while TFeO and MgO continue to migrate to bottom, and crystallization environment is a relatively closed and steady system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1369 (2013)
Spectral Characteristics and Implications of Quartz from Heliao Lead-Zinc Polymetallic Ore District in the South of Qinzhou-Hangzhou Joint Belt
Lv Wen-chao, YANG Zhi-jun, ZHOU Yong-zhang, LI Hong-zhong, ZENG Xiang-qing, CHEN Qing, LIANG Jin, and ZENG Chang-yu
The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rockThe XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock→near ore body rock→mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It’s a unique to mineralized rock that the quartz’s absorption peak at 1 050 cm-1 was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn’t have enough hydrothermal influence, so it’s not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1374 (2013)
Effect of Dynamic High-Pressure Micro-Fluidization on the Structure of Maize Amylose
TU Zong-cai, YIN Yue-bin, ZHANG Qiu, and WANG Hui
The effect of dynamic high-pressure micro-fluidization (DHPM) at 80, 120, 160, and 200 MPa on the structure of maize amylose was investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), Xray diffraction, and FT-IR spectroscopy. SEM analysis showed that the surface appearances of maize amyloThe effect of dynamic high-pressure micro-fluidization (DHPM) at 80, 120, 160, and 200 MPa on the structure of maize amylose was investigated using scanning electron microscopy (SEM), atomic force microscope (AFM), Xray diffraction, and FT-IR spectroscopy. SEM analysis showed that the surface appearances of maize amylose were altered and the starch granules were partially congregated together after DHPM treatment. AFM images showed that the treated starch molecules are cross-linked to each other and arranged in a close mesh structure. Xray diffraction spectra and IR spectra indicated that relative crystallinity declined gradually with the pressure increasing. The results provide a theoretical basis for starch modification of DHPM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1379 (2013)
Research on X-Ray Multispectrum Imaging Based on Variable Energy
CHEN Ping, HAN Yan, and PAN Jin-xiao
In conventional X-ray imaging based on fixed energy, the ray image of the complicated structural component often appears overexposed or underexposed. This is because of the variations in the effective thickness of the component along the orientation of the X-ray penetration that exceed the limit of the dynamic range ofIn conventional X-ray imaging based on fixed energy, the ray image of the complicated structural component often appears overexposed or underexposed. This is because of the variations in the effective thickness of the component along the orientation of the X-ray penetration that exceed the limit of the dynamic range of the X-ray imaging system. Complete structural information cannot be obtained, and this lack will impact the quality of the X-ray image. To solve this problem, the technology of X-ray multispectrum imaging based on variable energy has advanced. In this new method, the tube voltage is adjusted several times to accommodate the full necessary range of effective thickness, and then, the extracted images are fused to reconstruct the full projection information. Experiment shows that for the 12 bit imaging system, the new technology makes the system’s dynamic range expand 4 times, also completely represent the internal structure information of a complicated structural component..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1383 (2013)
Spectra of Dark Green Jade from Myanmar
MAO Jian, CHAI Lin-tao, GUO Shou-guo, FAN Jian-liang, and BAO Feng
Chemical compositions and spectral characteristics of one type of dark green jades assumed from omphacite jadeite from Myanmar jadeite mining area were studied by X-ray powder diffraction(XRD), X-ray fluorescence spectra(XRF), Raman spectra(RM) and UV-Vis Spectroscopy, etc. Based on testing by XRD and XRF, it was shownChemical compositions and spectral characteristics of one type of dark green jades assumed from omphacite jadeite from Myanmar jadeite mining area were studied by X-ray powder diffraction(XRD), X-ray fluorescence spectra(XRF), Raman spectra(RM) and UV-Vis Spectroscopy, etc. Based on testing by XRD and XRF, it was shown that it belongs to iron-enriched plagioclase, including albite and anorthite. The compositions range is between Ab0.731An0.264Or0.004 and Ab0.693An0.303Or0.004. Raman spectra of samples, albite jade and anorthite were collected and analyzed. Additionally, the distributions of Si, Al in the crystal structure were also discussed. UV-Vis spectra showed that dark green hue of this mineral is associated with d—d electronic transition of Fe3+ and Cr3+..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1388 (2013)
Research on the Application of Principal Component Analysis and Improved BP Neural Network to the Determination of Fe and Ti Contents in Geological Samples
XU Li-peng, GE Liang-quan, GU Yi, LIU Min, ZHANG Qing-xian, LI Fei, and LUO Bin
Aiming at forecasting elemental contents in geological samples accurately, a principal component analysis and improved BP (PCA-BP) neural network theory is proposed in the present work. The samples from west Tianshan were measured through X-ray fluorescence measurement method, and the X-Ray fluorescence counts of each Aiming at forecasting elemental contents in geological samples accurately, a principal component analysis and improved BP (PCA-BP) neural network theory is proposed in the present work. The samples from west Tianshan were measured through X-ray fluorescence measurement method, and the X-Ray fluorescence counts of each element such as Fe, Ti, V, Pb, Zn, etc. were input to the PCA-BP neural network as input variables to forecast Fe and Ti contents in uncertified geological samples quantitatively. The results show that the PCA-BP neural network can give an ideal result, and the relative error between the forecast data and chemical analysis data is less than 3%. This method provides a new and effective approach to forecasting elemental contents in geological samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1392 (2013)
Stellar Spectrum Parameter Measurement Based on Line Index by Linear Regression
TAN Xin, PAN Jing-chang, WANG Jie, LUO A-li, and TU Liang-ping
Using the Lick line index, according to the magnanimity characteristics of the spectrum an efficient algorithm of the atmospheric physical parameters measurement by the linear regression method from the point of view of statistical regression was designed. The linear regression was used to achieve the best regression eUsing the Lick line index, according to the magnanimity characteristics of the spectrum an efficient algorithm of the atmospheric physical parameters measurement by the linear regression method from the point of view of statistical regression was designed. The linear regression was used to achieve the best regression effect by selecting the type of regression and the composition of line index. The formula obtained from the regression model makes the computation speed fast when applied to new data, and the clarity and ease of analysis processing can not be reached by other methods. The experimental results show that through the line index regression method to get the atmospheric physical parameters is feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1397 (2013)
Interference Hyperspectral Data Compression Based on Spectral Classification and Local DPCM
TU Xiao-long, HUANG Min, Lv Qun-bo, WANG Jian-wei, and PEI Lin-lin
In order to get a high compression ratio, according to the spatial dimension correlation and the interference spectral dimension correlation of interference hyperspectral image data, the present article provides a new compression algorithm that combines spectral classification with local DPCM. This algorithm requires sIn order to get a high compression ratio, according to the spatial dimension correlation and the interference spectral dimension correlation of interference hyperspectral image data, the present article provides a new compression algorithm that combines spectral classification with local DPCM. This algorithm requires spectral classification for the whole interference hyperspectral image to get a classification number matrix corresponding to the two-dimensional space and a spectral classification library corresponding to the interference spectra first, then local DPCM is performed for the spectral classification library to get a further compression. As the first step of the compression, the spectral classification is very important to the compression effect. This article analyzes the differences of compression effect with different standard and different accuracy of classification, the relative Euclidean distance standard is better than the angle standard and the interference RQE standard. Finally, this article chooses an appropriate standard of compression and achieves the combined compression algorithm with programming. Compared to JPEG2000, the compression effect of combined compression algorithm is better..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1401 (2013)
Design of High-Efficiency Double Compound Parabolic Concentrator System in Near Infrared Noninvasive Biochemical Analysis
GAO Jing, LU Qi-peng, PENG Zhong-qi, DING Hai-quan, and GAO Hong-zhi
High signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilizatioHigh signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilization efficiency. Firstly, with the request of collection efficiency in near infrared noninvasive biochemical analysis, the characteristic of emergent rays through compound parabolic concentrator (CPC) was analyzed. Then the maximum focusing angle range of the first stage CPC was determined. Secondly, the light utilization efficiency of truncated type was compared with standard DCPC, thus the best structure parameters of DCPC system were optimized. Lastly, combined with optical parameters of skin tissue, calculations were operated when incident wavelength is 1 000 nm. The light utilization efficiency of DCPC system, CPC-focusing mirror system, and non-optical collecting system was calculated. The results show that the light utilization efficiency of the three optical systems is 1.46%, 0.84% and 0.26% respectively. So DCPC system enhances collecting ability for human diffuse reflection light, and helps improve SNR of noninvasive biochemical analysis system and overall analysis accuracy effectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1406 (2013)
Spectral Repeatability of Regenerated Fiber Gratings Prepared by High Temperature Annealing
WANG Tao, HE Da-wei, WANG Yong-sheng, QUAN Yu, WANG Peng-fei, and YIN Ze-lin
Two groups of fiber Bragg gratings were fabricated by using UV laser, and group one was annealed at 850 ℃ in the high temperature furnace. Grating regeneration occurred after the initial grating vanished. For the regenerated gratings from group one, the variation in Bragg wavelength is 0.22 nm and the average transmissTwo groups of fiber Bragg gratings were fabricated by using UV laser, and group one was annealed at 850 ℃ in the high temperature furnace. Grating regeneration occurred after the initial grating vanished. For the regenerated gratings from group one, the variation in Bragg wavelength is 0.22 nm and the average transmissions strength is 2.57 dB, while the variation of transmission among ten gratings is 0.52 dB. Group two underwent post-annealing at 1 100 ℃ after the process of grating regeneration at 850 ℃. For the regenerated gratings from group two, the variation in Bragg wavelength is 0.41 nm and the average transmissions strength is 0.69 dB, while the variation of transmission among ten gratings is 0.16 dB. The variation in Bragg wavelength of grating with post-annealing is notably larger than that of the regenerated gratings in group one, which is caused by the small difference in fixed tension among the ten gratings. The process of grating regeneration has good reproducibility. The mass production of the regenerated gratings by high temperature annealing is feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1411 (2013)
Research on Improving Spectrum Resolution Based on Electro-Optic Modulation Wollaston Prism Group
LI Yuan, CHEN Zhi-gang, LI Kai, and SONG Zhen-duo
Under the condition of no substantial change in the crystal size of the optical interference device, in order to improve the static spectrum resolution of the spectrum analysis equipment, the optical interference system of electro-optic modulation was designed. Wollaston prism group was used on the basis of analysis ofUnder the condition of no substantial change in the crystal size of the optical interference device, in order to improve the static spectrum resolution of the spectrum analysis equipment, the optical interference system of electro-optic modulation was designed. Wollaston prism group was used on the basis of analysis of the methods for increasing scanning range of the optical path of the static interference system. In the meantime, crystal refractive index was modulated by electro-optic modulation technique, and the range of the optical path difference was derived. Finally, the synthesized optical path difference function and spectrum resolution of the system was given in a modulation cycle. Experiments used three Wollaston prisms with same size and structural angle to constitute Wollaston prism group, and the signal was modulated by type SGT-3 acousto-optic modulator devices. Experimental results show that the interference fringes image after eliminating redundant processing can be effectively fused. Modulated interference image has a little distortion, but meets the requirements to reduce the spectrum distribution function after linearity correction. The spectrum resolution increased nearly by an order of magnitude compared to the static interference with the same crystal size..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1415 (2013)
The Improved Design of Encoding Mask and the Correcting Method for Recovered Spectral Images in Hadamard Transform Spectral Imager Based on DMD
XU Jun, XIE Cheng-wang, LIU Hai-wen, LIU Qiang, and LI Bin-cheng
A novel type of DMD-based Hadamard transform spectral imager is introduced. Taking the 7-order S-matrix as an example for discussion, the present paper develops an improved design of Hadamard encoding mask, which makes the dispersed spectrum of all pixels to be encoded by seven elements strictly. A correcting method foA novel type of DMD-based Hadamard transform spectral imager is introduced. Taking the 7-order S-matrix as an example for discussion, the present paper develops an improved design of Hadamard encoding mask, which makes the dispersed spectrum of all pixels to be encoded by seven elements strictly. A correcting method for the recovered spectral images is proposed, and eventually 6 high-quality spectral images are obtained when Hadamard transform spectral imager operates based on 7-order S-matrix. Similarly, if the spectral imager operates based on n-order S-matrix, n-1 spectral images can be obtained. The experimental results show that the improved design and the correction method are feasible and effective..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1419 (2013)
Study on Phase Correction Method of Spatial Heterodyne Spectrometer
WANG Xin-qiang, YE Song, ZHANG Li-juan, and XIONG Wei
Phase distortion exists in collected interferogram because of a variety of measure reasons when spatial heterodyne spectrometers are used in practice. So an improved phase correction method is presented. The phase curve of interferogram was obtained through Fourier inverse transform to extract single side transform spePhase distortion exists in collected interferogram because of a variety of measure reasons when spatial heterodyne spectrometers are used in practice. So an improved phase correction method is presented. The phase curve of interferogram was obtained through Fourier inverse transform to extract single side transform spectrum, based on which, the phase distortions were attained by fitting phase slope, so were the phase correction functions, and the convolution was processed between transform spectrum and phase correction function to implement spectrum phase correction. The method was applied to phase correction of actually measured monochromatic spectrum and emulational water vapor spectrum. Experimental results show that the low-frequency false signals in monochromatic spectrum fringe would be eliminated effectively to increase the periodicity and the symmetry of interferogram, in addition when the continuous spectrum imposed phase error was corrected, the standard deviation between it and the original spectrum would be reduced form 0.47 to 0.20, and thus the accuracy of spectrum could be improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1424 (2013)
Temperature Compensation Strategy and Implementation for Photoelectric Modulation Interferometer with Large Optical Path Difference
WANG Yan-chao, WANG Zhi-bin, ZHANG Ji-long, and CHEN You-hua
For temperature drift in hypervelocity photoelectric modulation interferometer, a control model of temperature compensation is presented including voltage and phase compensation. First, according to the similar and modeling theory, an equivalent circuit model of mechanical properties of hypervelocity photoelectric moduFor temperature drift in hypervelocity photoelectric modulation interferometer, a control model of temperature compensation is presented including voltage and phase compensation. First, according to the similar and modeling theory, an equivalent circuit model of mechanical properties of hypervelocity photoelectric modulation interferometer was established, the impact of temperature drift on its resonance frequency was analyzed, a mathematical model was set up, which contains drive voltage, frequency and resonance frequency, and the control method was determined for high optical path difference to get steady. Then, a digital method including voltage and phase compensation is given for optical path difference deviation control, which merges the DPLL and program of voltage and phase compensation. Finally, the control method was tested through experiment system. A test between drive control system including voltage and phase compensation and traditional drive control system was executed, using a laser doppler vibrometer to record the amount of change in optical path difference within 3 hours. Results show that the optical path difference deviation caused by temperature drift in long term is reduced by about 50%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1429 (2013)
Optimum Design of Imaging Spectrometer Based on Toroidal Uniform-Line-Spaced (TULS) Spectrometer
XUE Qing-sheng, and WANG Shu-rong
Based on the geometrical aberration theory, a optimum-design method for designing an imaging spectrometer based on toroidal uniform grating spectrometer is proposed. To obtain the best optical parameters, twice optimization is carried out using genetic algorithm(GA) and optical design software ZEMAX. A far-ultraviolet(Based on the geometrical aberration theory, a optimum-design method for designing an imaging spectrometer based on toroidal uniform grating spectrometer is proposed. To obtain the best optical parameters, twice optimization is carried out using genetic algorithm(GA) and optical design software ZEMAX. A far-ultraviolet(FUV) imaging spectrometer is designed using this method. The working waveband is 110～180 nm, the slit size is 50 μm×5 mm, and the numerical aperture is 0.1. Using ZEMAX software, the design result is analyzed and evaluated. The results indicate that the MTF for different wavelengths is higher than 0.7 at Nyquist frequency 10 lp·mm-1, and the RMS spot radius is less than 14 μm. The good imaging quality is achieved over the whole working waveband, the design requirements of spatial resolution 0.5 mrad and spectral resolution 0.6 nm are satisfied. It is certificated that the optimum-design method proposed in this paper is feasible. This method can be applied in other waveband, and is an instruction method for designing grating-dispersion imaging spectrometers..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1433 (2013)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1 (2013)
Research Articles
Texture Variation of CC 5052 Aluminum Alloy Slab from Surface to Center Layer by XRD
CHEN Ming-biao, LIU Wen-chang, MA Xiao-yi, LI Jian, YANG Qing-xiang, WANG Shan1, MA Min, LIU Chang, and Zhao Y M
For improvement of the processing and gaining uniformity texture structure and performance of direct chill cast CCAA 5052 aluminum alloy band after first hot rolling with different reduction, the material was annealed at 454 ℃ and then cold rolling with different reduction was conducted, the texture at surface, quarterFor improvement of the processing and gaining uniformity texture structure and performance of direct chill cast CCAA 5052 aluminum alloy band after first hot rolling with different reduction, the material was annealed at 454 ℃ and then cold rolling with different reduction was conducted, the texture at surface, quarter and center layer of the sample was tested and examined by X-ray diffraction method, the data calculated using special software and the difference of texture at surface, quarter and center layer was analyzed. There existed an elevated gradient of intensity from surface layer to center layer after cold rolled with less than or equal to 40% reduction, The main texture of β is stronger mainly due to transformation from remainder exposure, while the goss and remainder is infirm, the state of texture at each layer is close to each other after cold rolling with reduction high than 56.1%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 1364 (2013)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20