Journals >Spectroscopy and Spectral Analysis
Contents
2014
Volume: 34 Issue 8
57 Article(s)
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Research Article
Vibrational Spectra of Caesious Nephritefrom Qinghai Province
CHEN Quan-li, XU Ya-lan, AI Su-jie, HE An-qi, and YIN Zuo-wei
Qinghai caesious nephrite is discovered in the 1990s in the Golmud area of Qinghai Province. The conventional gemological testing methods, electron microprobe, infrared absorption spectroscopy and Raman spectroscopy were used in this study to analyze the chemical composition and infrared spectra characteristics of the Qinghai caesious nephrite is discovered in the 1990s in the Golmud area of Qinghai Province. The conventional gemological testing methods, electron microprobe, infrared absorption spectroscopy and Raman spectroscopy were used in this study to analyze the chemical composition and infrared spectra characteristics of the caesious nephrite, selected from the jade mine of Xiaozhaohuo river in Golmud area. The results show that, the gemological physical properties of the Qinghai caesious nephrite are similar to other origin nephrite. Electron microprobe analysis indicates that the MgO, CaO and SiO2 are the major and stable composition for the caesious nephrite. The content of MgO and CaO are 18.572%～23.603% and 12.333%～12.807% respectively. Moreover, the content of SiO2 is 56.799%～59.926%. In addition, it also contains a higher content of FeOT (Wt%: 1.924%～8.699%) and an amount of Al2O3, TiO2 and Na2O. Infrared absorption and Raman spectra show that the Qinghai caesious nephrite has a characteristic spectral features of tremolite indicating it is mainly composed of tremolite. The different frequency of the infrared absorption bands is due to the difference of Mg—Fe2+ isomorphous substitution and Fe2+ content of the caesious nephrite. Comprehensive analysis of chemical composition and vibrational spectroscopy indicate that the color of dark gray blue for the Qinghai nephrite is mainly related to its high content of FeOT, and the Fe is a main coloring element..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2017 (2014)
Research on the Reflection Spectrum of Linear Chirped Fiber Bragg Grating under the Impact of Dynamic Stress
WANG Jing, JIANG Shan-chao, SHI Bin, SUI Qing-mei, WANG Zheng-fang, LI Xiao-fei, WANG Ning, and YANG Shuai
Dynastic stress field detection based on the linear chirped fiber Bragg grating (LCFBG) was proposed. Firstly, the reflectance spectra strain sensing model of LCFBG adopting the transfer matrix method was constructed, and attenuation sine function was used to simulate the dynamic stress field along LCFBG. In the simulaDynastic stress field detection based on the linear chirped fiber Bragg grating (LCFBG) was proposed. Firstly, the reflectance spectra strain sensing model of LCFBG adopting the transfer matrix method was constructed, and attenuation sine function was used to simulate the dynamic stress field along LCFBG. In the simulation experiment, the responding character of LCFBG reflection spectrum to different amplitude, different attenuation coefficient and different propagation speed of dynamic stress was studied in detail. The simulation results show that the reflectivity, wavelength and spectral shape of LCFBG reflection spectrum are related to the dynamic stress. However, the LCFBG reflection spectrum has different response to different parameters of dynamic stress. In a range, maximum reflectivity of LCFBG reflectance spectra increases when the amplitude and propagation speed of dynastic stress field becomes larger, but it decreases when the attenuation coefficient increases. Eventually, vibration sensor using LCFBG as the sensing element was designed, and then LCFBG dynamic stress fluctuations experiment platform was build. The data obtained from experiment agrees with the simulation results. Therefore, a novel detection method of dynamic stress field through real-time acquisition of LCFBG full spectral information is proposed in this article..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2021 (2014)
Experimental Investigations of Cavity Ring-Down Spectroscopy under Different Threshold Circuit Design
ZHAO Gang, LI Zhi-xin, MA Wei-guang*, FU Xiao-fang, TAN Wei, DONG Lei, ZHANG Lei, YIN Wang-bao, and JIA Suo-tang
In the present paper, the authors simply describe the principle of cavity ring-down spectroscopy (CRDS) measurement technology and introduce a threshold circuit, based on 555 timer IC (integrated circuit), applied to CRDS. And we verify the feasibility of the circuit. By means of changing the input resistor and input cIn the present paper, the authors simply describe the principle of cavity ring-down spectroscopy (CRDS) measurement technology and introduce a threshold circuit, based on 555 timer IC (integrated circuit), applied to CRDS. And we verify the feasibility of the circuit. By means of changing the input resistor and input capacity, we analyzee the influence of threshold circuit characteristics on single ring-down event, and found that the greater the input capacitance, and the smaller the input impedance of circuit, the more serious the distortion of measurement of ring-down curve, especially when the resistance is less than 50 Ω the ring-down time produces very big change. Then we collected and analyzed the C2H2 absorption signal at 6 531.780 5 cm-1 with different input resistance and input capacitance, and fitted the absorption line with Voigt profile. We found that the change of the input capacitance and resistance caused the distortion of fitting curve. Finally We give the optimal design of threshold circuit: the input impedance of the threshold circuit should be great, minimum of 100 Ω, the capacitive reactance should be as small as possible, preferably below 1 nf, at the same time it should be ensured that the threshold of the circuit time constant is much smaller than ring-down time. The experiment research on CRDS technique application has important reference value to threshold circuit design..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2026 (2014)
Research on the Preparation and Optical Absorption Properties of Two-Dimensional ZnO Array
QIAO Lu, ZHU Ya-bin, and XU Hao
The present paper’s main work is firstly preparing a single layer and a large area polystyrene microspheres mask, with 117, 350 and 500 nm in diameter, and then depositing a layer of zinc oxide thin film on the mask board by RF magnetron sputtering technique, using nanospheres lithography technique to remove the polystThe present paper’s main work is firstly preparing a single layer and a large area polystyrene microspheres mask, with 117, 350 and 500 nm in diameter, and then depositing a layer of zinc oxide thin film on the mask board by RF magnetron sputtering technique, using nanospheres lithography technique to remove the polystyrene spheres by soaking with tetrahydrofuran, and two-dimensional zinc oxide nano-array samples were obtained at last. The samples were characterized on the morphology and composition by scanning electron microscopy and energy dispersive X-ray spectrometer. The results showed that the samples are zinc oxide nanocluster formed by ordered cellular reticular structures. By measuring with absorption spectroscopy in the range from 300 to 800 nm at room temperature, the absorption peak turns up with broadening and red shift with the increase in the diameter of polystyrene colloidal spheres, namely the nano-particles diameters. As the sputtering time increases, that is, the increase in the zinc oxide film thickness, the light absorption rate increases. In addition, theoretical calculation based on the theory of discrete dipole approximation was performed to simulate the optical absorption properties of the zinc oxide nanocluster arrays between 300 and 800 nm. Dipole approximation theory can be used to calculate the absorption of the particles of any shape and size. Currently, the theoretical calculation results of various shapes of nanostructured metals such as gold and silver are consistent with the experimental results. But the application of the theory of discrete dipole approximation calculation of ZnO nanoparticles was rarely reported. In this paper, this theory has been used to calculate the optical absorption properties of triangle-shaped ZnO nanoparticles array. Light absorption characteristics were simulated according to changes in the dielectric constant and thickness of zinc oxide films, and the results can be used to explain the experimental results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2031 (2014)
The Recent Development of Fiber-Optic Chemical Sensor
WANG Jian, WEI Jian-ping, YANG Bo, GAO Zhi-yang, ZHANG Li-wei, and YANG Xue-feng
The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemicl sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introducded respectively. Sensing film preparation methods such aThe present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemicl sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introducded respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2035 (2014)
Gold Nanoparticle-Aptamer Based Colorimetric Biosensing Assays
LIU Jin-chuan, L Zhen-zhen, and CHEN Ai-liang
The single strand nucleic acid based aptamer could bound to targets with high sensitivity and specificity. Gold nanoparticles have strong particle space optical effects and could take a color change from red to blue when the dispersed nanoparticles were aggregated. Aptamer could be immobilized through covalent couplingThe single strand nucleic acid based aptamer could bound to targets with high sensitivity and specificity. Gold nanoparticles have strong particle space optical effects and could take a color change from red to blue when the dispersed nanoparticles were aggregated. Aptamer could be immobilized through covalent coupling or direct adsorption to the surface of gold nanoparticle. Various approaches have been designed for biosensing based on the target induced aptamer-gold nanoparticle system color changes. The recent developments in the gold nanoparticle-aptamer based colorimetric biosensing assays were reviewed and the directions for future research were discussed and proposed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2040 (2014)
Progress of Electro-Optic Polymer in the Field of Generation and Detection of Terahertz Waves by All-Optical Technique
WANG Xuan, JIANG Qiang, WANG Yue, ZHANG Wen-long, and LI Zhi-yuan
Research on and development of the high amplitude, broadband terahertz system based on ultra-short pulse, low-power laser system is a hot spot in the field of terahertz. So far, for all the reported THz bandwidths broader than 10 THz, there always exist strong dispersion and absorption gaps associated with the lattice Research on and development of the high amplitude, broadband terahertz system based on ultra-short pulse, low-power laser system is a hot spot in the field of terahertz. So far, for all the reported THz bandwidths broader than 10 THz, there always exist strong dispersion and absorption gaps associated with the lattice resonance in either the photoconductive materials or crystalline EO materials. If such THz sources and detectors are employed in spectroscopic studies, spectral information in these gaps cannot be extracted. One of the advantages of using amorphous electro-optic polymer films as THz emitters and sensors is that there is no dispersion or absorption resulting from the lattice resonance effect, making a gap-free THz spectrum possible. Another advantage of electro-optic polymer films is the ease of fabrication and handling, in contrast to the extremely thin crystalline electro-optic materials used for existing broadband THz system. In addition, we can engineer the electro-optic polymeric materials to achieve small phase mismatch and high electro-optic coefficients such that brightness and broad bandwidth of THz radiation can be obtained. In this thesis a theoretical description of electro-optic effect based on electro-optic polymer and the second-order nonlinear chromophores synthesis is reviewed. In the past 20 years, progress in electro-optic polymer in the field of generating and detecting terahertz radiation by all-optical techniques is summarized, including the terahertz systems based on copolymer and the guest-host polymer induced by Titanium doped sapphire femtosecond laser and based on the guest-host polymer at communication wavelengths..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2053 (2014)
Upconversion and Mid-Infrared Fluorescence Properties of Ho3+/Yb3+ Co-Doped 50SiO2-50PbF2 Glass Ceramic
ZHANG Xiao-guang, REN Guo-zhong, and YANG Huai
In the present paper, the upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2-50PbF2 glass ceramic (GC) were studied. The GC has the following composition (in mol%): 50SiO2-50PbF2-1YbF3-0.5HoF3. The mixtures of about 10 g were placed in a corundum crucible and melted at 1 000 ℃ for 15 minIn the present paper, the upconversion and mid-infrared fluorescence properties of Ho3+/Yb3+ co-doped 50SiO2-50PbF2 glass ceramic (GC) were studied. The GC has the following composition (in mol%): 50SiO2-50PbF2-1YbF3-0.5HoF3. The mixtures of about 10 g were placed in a corundum crucible and melted at 1 000 ℃ for 15 min in a SiC electric furnace in air and then poured on a brass plate. The GCs were obtained just by heat treatment at 450 ℃. The X-ray diffraction pattern of the GC indicates that very small size crystals were precipitated in the precursor glass by heat treatment. The GCs have as high transmittance as glasses. The GCs have higher absorption cross section and narrower absorption peaks compared to the corresponding glasses, indicating that fluoride is doped with Ho ions. The Judd-Ofelt intensity parameters were determined from the absorption spectrum and Judd-Ofelt theory. The Ω2 value is 0.17×10-20 cm2 lower than that of fluoride glass ZBLA (2.28×10-20 cm2), because of Ho3+ doping in PbF2 microcrystal. The intense green upconversion light was observed in Ho3+/Yb3+ co-doped 50SiO2-50PbF2 GCs excited by 980 nm laser diode. A main emission band centered around 540 nm (green), and three week emission bands centered around 420 nm(violet), 480 nm (blue), and 650 nm (red) which correspond to the Ho3+: (5F4→5I8), (5G6→5I8), (8K3→5I8) and (5F5→5I8) transitions, respectively, were simultaneously observed in GCs. Compared with the glass sample, GCs have significantly intension in the green and blue upconversion fluorescence, and not significant change in the red upconversion fluorescence. Those changes are because that Ho ion in GCs locates in lower phonon energy environment than in glasses. Lower phonon energy can make the nonradiative relaxation rate reduce, which improves the green light upconversion efficiency, at the same time reduces the population of the intermediate energy level (5I7) of the red light radiation. The 2.9 μm mid-infrared light was observed in GC sample, but not in glass precursor excited by 980 nm laser diode..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2060 (2014)
Effect of Eu Ions on the Ag Nanoparticles Precipitation and Their Optical Properties in Borate Glasses
LIU Zhi-liang, JIAO Qing, and QIU Jian-bei
Eu-Ag co-doped borate glasses were prepared by the high temperature solid method in the present work. Absorption and emission spectra were employed to investigate the precipitation of Ag nanoparticles, which is influenced by the network form B2O3 and the co-doped Eu ions. It was found in the absorption spectra of Eu-AgEu-Ag co-doped borate glasses were prepared by the high temperature solid method in the present work. Absorption and emission spectra were employed to investigate the precipitation of Ag nanoparticles, which is influenced by the network form B2O3 and the co-doped Eu ions. It was found in the absorption spectra of Eu-Ag co-doped sample that a broad band centered at about 410 nm emerged and their intensity decreased with the increase in the B2O3 concentration. Meanwhile, under the excitation of 340 nm, a broad emission band was observed in the wavelength range of 350～600 nm, which belongs to the blue-green light of Ag aggregates. The intensity of the Ag aggregates presented an increasing tendency with the increase in the B2O3 contents. The weak characteristic emission of Ag aggregates and Eu3+ was observed respectively in their singly doped samples. It is concluded that both their emissions get significant enhancement when Eu ions and Ag ions are used for co-doping the sample. In addition, the increased absorption of Ag nanoparticles was detected with the increase in the Eu ions concentration. Herein, the mechanism behind Eu3+ contribution to the precipitation of Ag nanoparticles is discussed in detail. The luminescence properties of borate glasses can be controlled by the microstructure of the borate glasses. Therefore, the white emission can be realized by the adjustment of glass structure and Eu ions concentration, owing to the red light from Eu3+: 5D0→7FJ electronic transition and the blue-green light form the broad emission of Ag aggregates. The borate glasses are expected to be the candidates for the light-emission diode (LED) luminescent materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2065 (2014)
Visible and Near Infrared Spectroscopy Combined with Recursive Variable Selection to Quantitatively Determine Soil Total Nitrogen and Organic Matter
JIA Sheng-yao, TANG Xu, YANG Xiang-long, LI Guang, and ZHANG Jian-ming
In the present work, recursive variable selection methods (updating both the model coefficients and effective variables during the prediction process) were applied to maintain the predictive abilities of calibration models. This work compared the performances of partial least squares (PLS), recursive PLS (RPLS) and thrIn the present work, recursive variable selection methods (updating both the model coefficients and effective variables during the prediction process) were applied to maintain the predictive abilities of calibration models. This work compared the performances of partial least squares (PLS), recursive PLS (RPLS) and three recursive variable selection methods, namely variable importance in the projection combined with RPLS (VIP-RPLS), VIP-PLS, and uninformative variable elimination combined with PLS (UVE-PLS) for the measurement of soil total nitrogen (TN) and organic matter (OM) using Vis-NIR spectroscopy. The dataset consisted of 195 soil samples collected from eight towns in Wencheng County, Zhejiang Province, China. The entire data set was split randomly into calibration set and prediction set. The calibration set was composed of 120 samples, while the prediction set included 75 samples. The best prediction results were obtained by the VIP-RPLS model. The coefficient of determination (R2) and residual prediction deviation (RPD) were respectively 0.85, 0.86 and 2.6%, 2.7% for soil TN and OM. The results indicate that VIP-RPLS is able to capture the effective information from the latest modeling sample by recursively updating the effective variables. The proposed method VIP-RPLS has the advantages of better performance for Vis-NIR prediction of soil N and OM compared with other methods in this work..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2070 (2014)
Near Infrared Spectrum Analysis and Meaning of the Soil in 512 Earthquake Surface Rupture Zone in Pingtong, Sichuan
YI Ze-bang, CAO Jian-jin, LUO Song-ying, WANG Zheng-yang, and LIAO Yi-peng
Through modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Pingtong town, Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovThrough modern near infrared spectrum, the authors analyzed the yellow soil from the rupture zone located in Pingtong town, Pingwu, Sichuan province. By rapid identification of the characteristic of peak absorption of mineral particles, the result shows that the soil samples mainly composed of calcite, dolomite, muscovite, sericite, illite, smectite, talc, tremolite, actinolite, chlorite, etc. And the mineral compositions of the soil is basically the same with the yellow soil in Sichuan region. By analyzing and comparing it was revealed that part of mineral compositions of the soil are in accordance with the characteristics of the rock mineral compositions below the rupture zone, indicating that part of the minerals of the soil’s evolution is closely related to the rock compositions in this area; and the compositions of the clay mineral in the rupture zone is similar to the Ma Lan loess in the north of China, so it is presumed that the clay minerals in these two kinds of soil have the same genetic type. The characteristic of the mineral composition of the soil is in accordance with evolution characteristics of the rocks which is bellow the rupture zone, also it was demonstrated that the results of soil minerals near-infrared analysis can effectively analyze the mineral particles in the soil and indicate the pedogenic environment. Therefore, the result shows the feasibility of adopting modern near-nfrared spectrum for rapid analysis of mineral particles of the soil and research of geology. Meanwhile, the results can be the foundation of this region’s soil mineral analysis, and also provide new ideas and methods for the future research of soil minerals and the earthquake rupture zone..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2076 (2014)
Near Infrared Cavity Enhanced Absorption Spectroscopy Study of N2O
WU Zhi-wei, DONG Yan-ting, and ZHOU Wei-dong
Using a tunable near infrared external cavity diode laser and a 650mm long high finesse optical cavity consisting of two highly reflective (R＝99.97% at 6 561.39 cm-1) plan-concave mirrors of curvature radius ~1 000 mm, a cavity enhanced absorption spectroscopy (CEAS) system was made. The absorption spectra centered at Using a tunable near infrared external cavity diode laser and a 650mm long high finesse optical cavity consisting of two highly reflective (R＝99.97% at 6 561.39 cm-1) plan-concave mirrors of curvature radius ~1 000 mm, a cavity enhanced absorption spectroscopy (CEAS) system was made. The absorption spectra centered at 6 561.39 cm-1 of pure N2O gas and gas mixtures of N2O and N2 were recorded. According to the absorption of N2O at 6 561.39 cm-1 in the cavity, the measured effective absorption path was about 1 460 km. The spectra line intensity and line-width of N2O centered at 6 561.39 cm-1 were carefully studied. The relationship between the line-width of absorption spectra and the gas pressure was derived. The pressure broadening parameter of N2 gas for N2O line centered at 6 561.39 cm-1 was deduced and given a value of ~(0.114±0.004) cm-1·atm-1. The possibility to detect trace N2O gas in mixture using this CEAS system was investigated. By recording the absorption spectra of N2O gas mixtures at different concentration, the relationship between the line intensity and gas concentration was derived. The minimum detectable absorption was found to be 2.34×10-7 cm-1 using this cavity enhanced absorption spectroscopy system. And te measurement precision in terms of relative standard deviation (RSD) for N2O is ~1.73%, indicating the possibility of using the cavity enhanced absorption spectroscopy system for micro gas N2O analysis in the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2081 (2014)
Near-Infrared Reflectance Spectroscopy Analytic Model Established for the IVDMD of Cichorium intybus L
HU Chao, BAI Shi-qie, ZHANG Yu, YAN Jia-jun, YOU Ming-hong, LI Da-xu, BAI Ling, and ZHANG Jin
Chicory (Cichorium intybus L.) is a new type of forage grasses of high yield and quality with a great value of popularization and utilization. In vitro dry matter digestibility (IVDMD) is one of the important indicators of the nutritional value of forage evaluation. For the study of establishment of Chicory IVDMD NIRS Chicory (Cichorium intybus L.) is a new type of forage grasses of high yield and quality with a great value of popularization and utilization. In vitro dry matter digestibility (IVDMD) is one of the important indicators of the nutritional value of forage evaluation. For the study of establishment of Chicory IVDMD NIRS quantitative analysis model, seventy-two species with different genotypes, different growth stages of 204 chicory samples of aboveground material were collected, and by Fourier transform near-infrared diffuse reflectance spectroscopy, through the use of different regression algorithms, can comparing different spectral ranges and spectral pretreatment methods, eight chicory IVDMD NIRS calibration models were established, and the best calibration model parameters were chosen. Its calibration coefficient of determination (R2cal) and external validation coefficient of determination (R2val) were 0.953 17 and 0.904 55, calibration standard deviation (RMSEC) and predictive standard deviation (RMSEP) was 1.977 99% and 2.008 82%, and the correlation coefficient (r) between predicted values and chemical values was 0.951 08. The results show that using NIRS to determine chicory IVDMD is feasible, and provided a rapid analysis method for the determination IVDMD of chicory..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2085 (2014)
Characteristic Wavelengths Selection of Soluble Solids Content of Pear Based on NIR Spectral and LS-SVM
FAN Shu-xiang, HUANG Wen-qian, LI Jiang-bo, ZHAO Chun-jiang, and ZHANG Bao-hua
To improve the precision and robustness of the NIR model of the soluble solid content (SSC) on pear. The total number of 160 pears was for the calibration (n=120) and prediction (n=40).Different spectral pretreatment methods, including standard normal variate (SNV) and multiplicative scatter correction (MSC) were used To improve the precision and robustness of the NIR model of the soluble solid content (SSC) on pear. The total number of 160 pears was for the calibration (n=120) and prediction (n=40).Different spectral pretreatment methods, including standard normal variate (SNV) and multiplicative scatter correction (MSC) were used before further analysis. A combination of genetic algorithm (GA) and successive projections algorithm (SPA) was proposed to select most effective wavelengths after uninformative variable elimination (UVE) from original spectra, SNV pretreated spectra and MSC pretreated spectra respectively. The selected variables were used as the inputs of least squares-support vector machine (LS-SVM) model to build models for determining the SSC of pear. The results indicated that LS-SVM model built using SNVE-UVE-GA-SPA on 30 characteristic wavelengths selected from full-spectrum which had 3112 wavelengths achieved the optimal performance. The correlation coefficient (Rp) and root mean square error of prediction (RMSEP) for prediction sets were 0.956, 0.271 for SSC. The model is reliable and the predicted result is effective. The method can meet the requirement of quick measuring SSC of pear and might be important for the development of portable instruments and online monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2089 (2014)
A Wavelength Selection Approach of Near Infrared Spectra Based on SCARS Strategy and Its Application
LIU Guo-hai, XIA Rong-sheng, JIANG Hui, MEI Cong-li, and HUANG Yong-hong
According to the characteristics of near infrared spectral(NIR)data, a new tactic called stability competitive adaptive reweighted sampling (SCARS) is employed to select characteristic wavelength variables of NIR data to build PLS model. This method is based on the stability of variables in PLS model. SCARS algorithm cAccording to the characteristics of near infrared spectral(NIR)data, a new tactic called stability competitive adaptive reweighted sampling (SCARS) is employed to select characteristic wavelength variables of NIR data to build PLS model. This method is based on the stability of variables in PLS model. SCARS algorithm consists of a number of loops. In each loop, the stability of each corresponding variable is computed at first. Then enforced wavelength selection and adaptive reweighted sampling (ARS) is used to select important variables according to the stability of variables. The selected variables are kept as a variable subset and further used in the next loop. After the running of all loops, a number of subsets of variables are obtained and root mean squared error of cross validation (RMSECV) of PLS models is computed. The subset of variables with the lowest RMSECV is considered as the optimal variable subset. Validated by NIR data set of protein fodder solid-state fermentation process, the SCARS-PLS prediction model is better than PLS models based on wavelengths selected by competitive adaptive reweighted sampling (CARS) and Monte Carlo uninformative variable elimination (MC-UVE) methods. As a result, twenty one wavelength variables are selected by SCARS method to build the PLS prediction model with the predicted root mean square error (RMSEP) valued at 0.054 3 and correlation coefficient (Rp) 0.990 8. The results show that SCARS tactic can efficiently improve the accuracy and stability of NIR wavelength variables selection and optimize the precision of prediction model in solid-state fermentation process. The SCARS method has a certain application value..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2094 (2014)
Discrimination of Adulterated Milk Based on Euclidian Distances between Two-Dimensional Infrared Correlation Spectra
YANG Ren-jie, YANG Yan-rong, DONG Gui-mei, DU Yan-hong, SHAN Hui-yong, and ZHANG Wei-yu
Based on Euclidian distances between synchronous two-dimensional infrared correlation spectra, in terms of the average Euclidian distances between unknown samples and “extreme samples”, and average intra- and inter- Euclidian distances of samples in the calibration set, a new method for the discrimination of adulterateBased on Euclidian distances between synchronous two-dimensional infrared correlation spectra, in terms of the average Euclidian distances between unknown samples and “extreme samples”, and average intra- and inter- Euclidian distances of samples in the calibration set, a new method for the discrimination of adulterated milk was proposed. Sixteen pure milk samples were collected and 16 adulterated milk samples with urea (0.01～0.3 g·L-1), and 16 adulterated milk samples with melamine (0.01～0.3 g·L-1) samples were prepared, respectively. The IR absorption spectra of all samples were measured at room temperature. The synchronous two-dimensional correlation spectra were generated from concentration-dependent spectral variation of adulterant in milk. The Euclidian distances were calculated between synchronous two-dimensional infrared correlation spectra of all samples. Then, the classification models were built respectively for adulterated milk with urea, and adulterated milk with melamine. The “extreme samples”, average intra- and inter- Euclidian distances were determined. Finally, the unknown samples in prediction set were predicted using constructed models in terms of classification rules of adulterated milk. The classification accuracy rates for pure milk and adulterated milk were 100%. The effectiveness of the proposed method was verified. The results obtained in this study revealed that synchronous two-dimensional infrared correlation spectra in combination with Euclidian distance has a feasible potential to discriminate adulterated milk and pure milk..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2098 (2014)
Applying Local Neural Network and Visible/Near-Infrared Spectroscopy to Estimating Available Nitrogen, Phosphorus and Potassium in Soil
WU Qian, YANG Yu-hong, XU Zhao-li, JIN Yan, GUO Yan, and LAO Cai-lian
To establish the quantitative relationship between soil spectrum and the concentration of available nitrogen, phosphorus and potassium in soil, the critical procedures of a new analysis method were examined, involving spectral preprocessing, wavebands selection and adoption of regression methods. As a result, a soil spTo establish the quantitative relationship between soil spectrum and the concentration of available nitrogen, phosphorus and potassium in soil, the critical procedures of a new analysis method were examined, involving spectral preprocessing, wavebands selection and adoption of regression methods. As a result, a soil spectral analysis model was built using VIS/NIRS bands, with multiplicative scatter correction and first-derivative for spectral preprocessing, and local nonlinear regression method (Local regression method of BP neural network). The coefficients of correlation between the chemically determined and the modeled available nitrogen, phosphorus and potassium for predicted samples were 0.90, 0.82 and 0.94, respectively. It is proved that the prediction of local regression method of BP neural network has better accuracy and stability than that of global regression methods. In addition, the estimation accuracy of soil available nitrogen, phosphorus and potassium was increased by 40.63%, 28.64% and 28.64%, respectively. Thus, the quantitative analysis model established by the local regression method of BP neural network could be used to estimate the concentration of available nitrogen, phosphorus and potassium rapidly. It is innovative for using local nonlinear method to improve the stability and reliability of the soil spectrum model for nutrient diagnosis, which provides technical support for dynamic monitoring and process control for the soil nutrient under different growth stages of field-growing crops..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2102 (2014)
Application of EMD Algorithm to the Dynamic Spectrum Non-Invasive Measurement of Hemoglobin
LIN Ling, LI Wei, ZHOU Mei, ZENG Rui-li, LI Gang, and ZHANG Bao-ju
Empirical mode decomposition (EMD) algorithm combined with the theory of dynamic spectrum extraction at frequency domain was applied to the noninvasive measurement of hemoglobin concentration. Fifty seven cases’ photoplethysmography was collected in the range of 636.98～1 086.86 nm in vivo. After the denoising preprocesEmpirical mode decomposition (EMD) algorithm combined with the theory of dynamic spectrum extraction at frequency domain was applied to the noninvasive measurement of hemoglobin concentration. Fifty seven cases’ photoplethysmography was collected in the range of 636.98～1 086.86 nm in vivo. After the denoising preprocess through the EMD method for each wavelength pulse wave of each sample separately, dynamic spectrum of each sample was made up of all peaks extracted by Fourier transform. Partial least squares regression model was used to establish the calibration and prediction of hemoglobin concentration. Compared to the modeling results without EMD, the correlation coefficient of predicted values and the real values was increased from 0.879 8 up to 0.917 6. The root mean square error of prediction set was reduced from 6.675 9 to 5.300 1 g·L-1 and the relative error was reduced from 8.45% to 6.71%. The modeling accuracy has been greatly improved. The results showed that EMD algorithm can be effectively applied to denoise the spectral data and improve the accuracy of the non-invasive measurement of blood components..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2106 (2014)
Study of Alkaline Lignin from Arundo donax Linn Based on FT Raman Spectroscopy
YOU Ting-ting, MA Jian-feng, GUO Si-qin, and XU Feng
Arundo donax linn, as a perennial energy crop, has promising application prospect. In the present study, Fourier transform Raman (FT Raman) spectroscopy was applied to determine the structural information of materials, milled wood lignin (MWL), and alkaline lignins (AL, under different treated time) from A. donax stem Arundo donax linn, as a perennial energy crop, has promising application prospect. In the present study, Fourier transform Raman (FT Raman) spectroscopy was applied to determine the structural information of materials, milled wood lignin (MWL), and alkaline lignins (AL, under different treated time) from A. donax stem nondestructively. The results indicated that, extractable compounds in A. donax had negative contribution to the Raman spectra without rising new Raman peaks. FT Raman spectrum of MWL indicated that MWL from A. donax was HGS type lignins. Compared with the spectra of MWL from wood materials, the peak at 1 173 cm-1 was much higher in intensity for the MWL from A. donax stem, which may be assigned to hydroxycinnamic acid by analyzing the standard. With respect to FT Raman spectra of ALs, the relatively highest intensity of 1 173 cm-1 was found in alkaline lignin (AL2), which was treated for 40 min by alkaline. Moreover, the peak of coniferaldehyde/sinapaldehyde (1 630 cm-1) was lowest in intensity while the band attributed to coniferyl alcohol/sinapyl alcohol (1 660 cm-1) was almost disappeared in AL2. It could be inferred that AL2 demonstrated a highest content of phenolic acid, which may improve its potential application, such as for antioxidant activity. Furthermore, the results obtained by FT Raman spectra were verified by two dimensional heteronuclear singlequantum coherence nuclear magnetic resonance analyses. Above all, FT Raman spectroscopy provided alternative safe, rapid, accurate, and nondestructive technology for lignin structure determination..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2112 (2014)
Baseline Correction Method for Raman Spectroscopy Based on B-Spline Fitting
WANG Xin, FAN Xian-guang, XU Ying-jie, WU Jing-lin, LIANG Jun, and ZUO Yong
Baseline drift is a widespread phenomenon in modern spectroscopy instrumentation, which would bring a very negative impact to the feature extraction of spectrum signal, and the baseline correction method is an important means to solve the problem, which is also the important part of Raman signal preprocessing. The geneBaseline drift is a widespread phenomenon in modern spectroscopy instrumentation, which would bring a very negative impact to the feature extraction of spectrum signal, and the baseline correction method is an important means to solve the problem, which is also the important part of Raman signal preprocessing. The general principle of baseline drift elimination is using the fitting method to the fit the baseline. The traditional fitting method is polynomial fitting, but this method is prone to over-fitting and under-fitting, and the fitting order is difficult to be determined. In this paper, the traditional method is improved; the B-spline fitting method is used to approach the baseline of Raman signal through constant iteration. The advantages of B-spline, namely low-order and smoothness, can help the method overcome the shortcomings of polynomial method. In the experiments, the Raman signal of malachite green and rhodamine B were detected, and then the proposed method and traditional method were applied to perform baseline correction. Experimental results showed that the proposed method can eliminate the Raman signal baseline drift effectively without over- and under-fitting, and the same order can be used in both positions where large or small baseline drift occurred. Therefore, the proposed method provided more accurate and reliable information for the further analysis of spectral data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2117 (2014)
Study on the Frontier Orbital and Raman Spectra of Aflatoxin B1 and Isomer
LI Tao, TANG Yan-lin, LING Zhi-gang, and LONG Zheng-wen
Through computation, this paper obtained Aflatoxin B1 and its trans-isomer molecules stable structure which was rarely reported by the density functional theory(DFT) with B3LYP complex function and 6-311+g(d, p) basis set. Through a single point calculations and geometry analysis, we know that the cis -structure is morThrough computation, this paper obtained Aflatoxin B1 and its trans-isomer molecules stable structure which was rarely reported by the density functional theory(DFT) with B3LYP complex function and 6-311+g(d, p) basis set. Through a single point calculations and geometry analysis, we know that the cis -structure is more stable than trans-structure. On the basis of this, Raman spectra of two molecules are calculated by the same method and basis set. compared with the Aflatoxin B1 cis -structure powder experimental Raman spectra, it was informed that numerical results with experimental results combined with a better. While 1 582, 3 065, 1 626 means to take the strongest of the three peaks of cis-structure raman characteristics, 1 616, 3 065, 1 659 cm-1 is indicated for the strongest of the three peaks of trans-structure raman characteristics. Use the Hirshfeld atom division method combined with Multiwfn software to analyze the composition of frontier orbital based on optimization calculation, and it was informed that the electrophilic ability of two m on olecules was stronger than the nucleophilic ability. The proportion of C1 atoms in LUMO orbital are respectively 21. 48 percent, 20. 62 percent by calculating, thus it is predicted that C1 atom is most main position spot depriving of the electronic in DNA to cause cancer. The above-mentioned research has certain theoretical directive significance in detection, transformation and toxicity inhibition of the cis-trans isomers..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2122 (2014)
Preparation, Characterization and Surface-Enhanced Raman Properties of Agarose Gel/Gold Nanoparticles Hybrid
MA Xiao-yuan, LIU Ying, and WANG Zhou-ping
Agarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy(SEM)、 and UV-Vis-NIR absorption spectroscopy. Experimental data indicated a uniformAgarose gel/gold nanoparticles hybrid was prepared by adding gold nanoparticles to preformed agarose gel. Nanocomposite structures and properties were characterized by transmission electron microscopy (TEM), scanning electron microscopy(SEM)、 and UV-Vis-NIR absorption spectroscopy. Experimental data indicated a uniform distribution of gold nanoparticles adsorbed on agarose gel network. And the excellent optical absorption properties were shown. Based on the swelling-contraction characteristics of agarose gel and the adjustable localized surface plasmon resonance (LSPR) of the gold nanoparticles, the nanocomposites were used as surface enhanced Raman scattering (SERS) substrate to detect the Raman signal molecules Nile blue A. Results revealed that the porous structure of the agarose gel provided a good carrier for the enrichment of the gold nanoparticles. The gold nanoparticles dynamic hot-spot effect arising from the agarose gel contraction loss of water in the air greatly enhanced the Raman signal..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2126 (2014)
Algae Identification Research Based on Fluorescence Spectral Imaging Technology Combined with Cluster Analysis and Principal Component Analysis
LIANG Man, HUANG Fu-rong, HE Xue-jia, and CHEN Xing-dan
In order to explore rapid real-time algae detection methods, in the present study experiments were carried out to use fluorescence spectral imaging technology combined with a pattern recognition method for identification research of different types of algae. The fluorescence effect of algae samples is obvious during thIn order to explore rapid real-time algae detection methods, in the present study experiments were carried out to use fluorescence spectral imaging technology combined with a pattern recognition method for identification research of different types of algae. The fluorescence effect of algae samples is obvious during the detection. The fluorescence spectral imaging system was adopted to collect spectral images of 40 algal samples. Through image denoising, binarization processing and making sure the effective pixels, the spectral curves of each sample were drawn according to the spectral cube .The spectra in the 400～720 nm wavelength range were obtained. Then, two pattern recognition methods, i.e. hierarchical cluster analysis and principal component analysis, were used to process the spectral data. The hierarchical cluster analysis results showed that the Euclidean distance method and average weighted method were used to calculate the cluster distance between samples, and the samples could be correctly classified at a level of the distance L=2.452 or above, with an accuracy of 100%. The principal component analysis results showed that first-order derivative, second-order derivative, multiplicative scatter correction, standard normal variate and other pretreatments were carried out on raw spectral data, then principal component analysis was conducted, among which the identification effect after the second-order derivative pretreatment was shown to be the most effective, and eight types of algae samples were independently distributed in the principal component eigenspace. It was thus shown that it was feasible to use fluorescence spectral imaging technology combined with cluster analysis and principal component analysis for algae identification. The method had the characteristics of being easy to operate, fast and nondestructive..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2132 (2014)
Application of Fluorescence Spectra and Parallel Factor Analysis in the Classification of Edible Vegetable Oils
WU Xi-jun, PAN Zhao, ZHAO Yan-peng, LIU Hai-long, and ZHENG Long-jiang
The fluorescence spectra of 22 samples of 8 kinds of edible vegetable oils (soybean oil, maize oil, olive oil, rice oil, peanut oil, walnut oil, sunflower oil and sesame oil) were measured with FS920 fluorescence spectrometer and the fluorescence matrixs (EEMs) were analyzed with parallel factor (PARAFAC) analysis modeThe fluorescence spectra of 22 samples of 8 kinds of edible vegetable oils (soybean oil, maize oil, olive oil, rice oil, peanut oil, walnut oil, sunflower oil and sesame oil) were measured with FS920 fluorescence spectrometer and the fluorescence matrixs (EEMs) were analyzed with parallel factor (PARAFAC) analysis model. To synthesize the capabilities of material characterization and component identification, fluorescence spectra combined with PARAFAC fulfill the classification of vegetable oils. The map feature (peak position, peak value and peak number) was obtained by analyzing three dimensional spectra and contour maps in the range of emission wavelength from 260 to 750 nm, and excitation wavelengths from 250 to 550 nm. The fluorescent substances (unsaturated fatty acids, vitamin E and its derivatives, chlorophyll and carotenoid) corresponding to spectrum peaks were determined. The factor-number was selected and the components (vitamin E and its derivatives, linoleic acid and linolenic acid, fatty acid oxidation products, vegetable oil oxidation products) corresponding to each factor were ascertained. The four-factor excitation and emission profiles and projection score plots of PARAFAC model were plotted. Different vegetable oils can be characterized and distinguished with the map features of fluorescence spectra and sample projection plots of PARAFAC model. The results demonstrate the capability of the combination of fluorescence spectra technology and four-factor PARAFAC model for differentiating and characterizing vegetable oils..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2137 (2014)
Commercial Orange Juice Beverages Detection by Fluorescence Spectroscopy Combined with PCA-ED and PLSR Methods
HU Yang-jun, ZHU Chun, CHEN Guo-qing, ZHANG Yong, KONG Fan-biao, LI Run, ZHU Zhuo-wei, WANG Xu, and GAO Shu-mei
In order to classify the orange juice beverages effectively, the fluorescence character differences of two kinds of orange juice beverages including 100% orange juice and orange drink were analyzed and compared, principal component analysis combined with Euclidean distance was adopted to classify two kinds of orange juIn order to classify the orange juice beverages effectively, the fluorescence character differences of two kinds of orange juice beverages including 100% orange juice and orange drink were analyzed and compared, principal component analysis combined with Euclidean distance was adopted to classify two kinds of orange juice beverages, and ideal classification results were obtained. Meanwhile, the orange juice content estimation model was established by using fluorescence spectroscopy combined with partial least squares regression method, and the correlation coefficient R, root mean square error of calibration RMSEC and root mean square error of prediction RMSEP were 0.997, 0.87% and 2.05%, respectively. The experimental results indicate that the calibration model offers comparatively accurate content estimation, which reflect the actual orange juice content in the commercial orange juice beverages. The exploration to classify orange juice beverages was carried out from two aspects of qualitative and quantitative analysis by employing fluorescence spectroscopy combined with chemometrics method, which can provide a new idea for the classification and adulteration detection of commercial orange juice beverages, and also can give certain reference basis for the quality control of orange juice raw material..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2143 (2014)
Rapid Recognition of Common Machine Oils Based on Laser Induced Fluorescence
LIU Xiao-hua, CHEN Si-ying, ZHANG Yin-chao, GUO Pan, CHEN He, and MU Tao-tao
A rapid recognition method of common engine oils, based on the principle of laser induced fluorescence (LIF), is proposed in the present paper. A 355 nm ultraviolet laser is used to induce fluorescence emission of 9 kinds of common machine oil samples. In total 450 groups of fluorescence spectral data are collected, ofA rapid recognition method of common engine oils, based on the principle of laser induced fluorescence (LIF), is proposed in the present paper. A 355 nm ultraviolet laser is used to induce fluorescence emission of 9 kinds of common machine oil samples. In total 450 groups of fluorescence spectral data are collected, of which 360 groups of data are used for classification training and 90 sets of data for identification. It was found that the fluorescence spectra of engine oils are distinct from each other visibly. The rapid identification of 90 groups of data is realized by using clustering analysis combined with principal component analysis. The recognition rate could reach up to 97.8%. Experiment demonstrated that the fast identification of diverse engine oils could be realized by using LIF combined with multivariate analysis method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2148 (2014)
Sensitive Determination of Bi3+ by Spectrofluorimetry Based on Graphene Oxide-Methylene Blue System
ZHAI Qiu-ge, GUO Peng, ZHOU Lin, and LIU Yan-ming
Graphene oxide was prepared by the modified Hummers method and characterized by field emission scanning electron microscopy. The interaction of graphene with methylene blue was studied by UV absorption, the intensity of two main absorption peaks of methylene blue decreased significantly after the fluorescence was quencGraphene oxide was prepared by the modified Hummers method and characterized by field emission scanning electron microscopy. The interaction of graphene with methylene blue was studied by UV absorption, the intensity of two main absorption peaks of methylene blue decreased significantly after the fluorescence was quenched, and the energy transfer didn’t occur because the overlap of the absorption spectrum of GO and the emission spectrum of MB is too small. Therefore, the fluorescence quenching of MB and GO was static. When adding a certain amount of Bi3+ in the graphene-methylene blue system, Bi3+ replaces the methylene blue from the graphene-methylene blue complexes because Bi3+ has the smaller volume and is more positively charged. The methylene blue therefore dissociates from the GO-MB complexes, resulting in the recovery of fluorescence of the system. Furthermore, the fluorescence of the system increases with the increase in the amount of Bi3+ due to the enhanced amount of MB in the system. A novel spectrofluorimetric method was therefore developed for the sensitive determination of Bi3+. Some parameters including the concentration of methylene blue, the amount of graphene oxide, the amount of nitric acid and the sequence of reagent adding were optimized to obtain higher sensitivity. The fluorescence of the system was detected at an emission wavelength of 667 nm with excitation at 690 nm. Under the optimized conditions, the concentration of Bi3+ showed good linear relationships with the fluorescence intensity in the range of 0.5～100 μmol·L-1, with correlation coefficients of r=0.995 5. The limits of detection for Bi3+ was 1.0×10－8 mol·L-1 (S/N=3). The selectivity of the proposed method was evaluated and the results showed that 1 000-fold K+, Ca2+, Na+, Mg2+, Cu2+; 100-fold Fe3+, Be2+, SiO2-, Al3+, Ni2+, Sb3+, NO－3, Cl－, F－, and 20-fold Pb2+, Hg2+, Cd2+ had negligible interference with the determination of Bi3+. The method has advantages of sensitivity, rapidness and low cost. It was used for the determination of Bi3+ in environmental water samples including pond water, rain water and sewage water with recoveries of 93.4%～105.2%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2152 (2014)
Preparation of H3PW12O40/MCM-48 and Its Photocatalytic Degradation of Pesticides
LIU Xia, LI Yan-zhou, GAN Qiang, and FENG Chang-gen
A composite catalyst H3PW12O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3PW12O40 (HPW) to molecular sieve MCM-48 by impregnation method, and its structure was characterized by Fourier transform infrared (FT-IR) spectra, small angle X-ray diffraction (XRD) patterns, nitrogen adsorption analysisA composite catalyst H3PW12O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3PW12O40 (HPW) to molecular sieve MCM-48 by impregnation method, and its structure was characterized by Fourier transform infrared (FT-IR) spectra, small angle X-ray diffraction (XRD) patterns, nitrogen adsorption analysis and High-resolution transmission electron microscopy (HRTEM) analysis. Photocatalytic degradation activities of HPW/MCM-48 against pesticides imidacloprid and paraquat were evaluated under UV radiation (365 nm). The results show that HPW/MCM-48 maintains the mesoprous molecular sieve structure of MCM-48 and the Keggin structure of HPW, while the BET surface area is 793.35 m2·g-1, pore volume is 1.46 cm3·g-1, average pore diameter is 2.76 nm, suggesting loading HPW on MCM-48 is a considerable way to improve its surface area. After 14 h UV irradiation (365 nm), 57.38% imidacloprid and 63.79% paraquat were degraded by 20 mg HPW/MCM-48 catalyst, while HPW and blank group degraded the two pesticides at the degradation rate of about 25% and 5%, respectively. Implying loading on MCM-48 could greaterly improve the degradation activity of HPW. The reslut of degradation kinetics show that, the degradation process of HPW/MCM-48 fits first order kinetics equation. The rate constant Ka of HPW/MCM-48 toward imidacloprid and paraquat are 0.089 h and 0.117 h, with the half-life t1/2 of 7.8 h and 5.9 h, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2157 (2014)
Using Hyperspectral Indices to Measure the Effect of Mine Dust on the Growth of Three Typical Desert Plants
ZHANG Peng-fei, GULI·Jiapaer, YIN Jun-qi, BAO An-ming, YAO Feng, and LIU Jin-ping
To examine the influence of coal dust from mining on vegetative growth, three typical plants from near an open-pit coalmine in an arid region were selected, and their spectral signals were determined. The present study was conducted near the Wucaiwan open-pit coalmine in the East Junggar Basin in Xinjiang. We extractedTo examine the influence of coal dust from mining on vegetative growth, three typical plants from near an open-pit coalmine in an arid region were selected, and their spectral signals were determined. The present study was conducted near the Wucaiwan open-pit coalmine in the East Junggar Basin in Xinjiang. We extracted nineteen vegetation indices and examined their correlation with the dust flux. The objective was to determine which parameters that quantify vegetation damage could provide a basis for environmental monitoring in arid regions. The results indicate that when coal dust damages vegetation, both chlorophyll and moisture are reduced, and the amount of carotenoids increases with increasing coal dust. The pigment-specific normalized difference (PSNDb), structure-insensitive pigment index (SIPI) and plant water index (PWI) were the most sensitive indices, and sacsaoul was most sensitive to coal-dust pollution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2162 (2014)
Research on the Phase and Optical Properties of nc-Si Films Prepared by Low Temperature Aluminum Induced Crystallization
DUAN Liang-fei, YANG Wen, YANG Pei-zhi, ZHANG Li-yuan, and SONG Zhao-ning
In the present paper, nanocrystalline silicon thin films on glass substrates were prepared by rapid thermal annealing (RTA) of RF magnetron sputtered system and α-Si/Al films at a low temperature in N2 atmosphere. Optical metallographic microscope, confocal optical microscopy, X-ray diffractometer, Raman scattering andIn the present paper, nanocrystalline silicon thin films on glass substrates were prepared by rapid thermal annealing (RTA) of RF magnetron sputtered system and α-Si/Al films at a low temperature in N2 atmosphere. Optical metallographic microscope, confocal optical microscopy, X-ray diffractometer, Raman scattering and UV-Vis-NIR spectrometers were used to characterize the surface morphology and the phase and optical properties of nc-Si films. The influence of annealing process on the nc-Si films properties was studied. The results showed that nc-Si films were obtained after aluminum induced crystallization of the α-Si/Al films at 300 ℃, withthe crystallization rate 15.56% and the grain size 1.75 nm. The surface uniformity and lattice distortion of nc-Si films reduced, while grain size, degree of crystallization and the optical band gap of the films increased with increasing annealing temperature from 300 to 400 ℃. As the annealing temperature increased from 400 to 500 ℃, although the degree of crystallization and grain size increased, the tendencies of all other characteristics were opposite. On the contrary, the surface uniformity and the lattice distortion increased, but the optical band gap of nc-Si films reduced. The optical properties of the resulting films were confirmed by the absorption model of nc-Si thin films, where the tendency of band gap changes is in consistent with the optical modeling..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2169 (2014)
Spectroscopic Characteristics Study of Morganite from Mozambique
YIN Zuo-wei, LI Xiao-lu, BAO De-qing, CHEN Quan-li, and ZHANG Miao
In recent years, morganite is becoming more and more popular due to its special color. The morganite samples located in the Republic of Mozambique were detailedly analyzed for its basic properties, chemical composition characteristics and spectroscopy properties by laser ablation plasma mass spectrometry (LA-ICP-MS), uIn recent years, morganite is becoming more and more popular due to its special color. The morganite samples located in the Republic of Mozambique were detailedly analyzed for its basic properties, chemical composition characteristics and spectroscopy properties by laser ablation plasma mass spectrometry (LA-ICP-MS), ultraviolet-visible absorption spectra (UV-Vis-NIR), infrared spectrum (IR) and Raman spectroscopy. The color parameters of morganite samples including the main wavelength, saturation, and lightness were got by UV-Vis-NIR. Chemical composition test showed higher content of Li, Rb, Cs and Mn in samples and chemical formula was calculated as Be3.209 0Al2.075 7Li0.425Si5.664O18(Na0.142 0Cs0.131 6). Infrared spectroscopy showed that morganite structure vibration area is mainly in the fingerprint area 400～1 200 and 900~1 200 cm-1 for the vibration of the ring Si—O—Si, 550~900 cm-1 for Be-O vibration area, and 450~530 cm-1 for Al—O vibration area. Because the Cs element content is higher in sample morganite and Cs belongs to higher atomic number elements, its existence may move the vibration frequency of Si—O—Si rings to the low position. Raman spectra showed 1 065 cm-1 for Si—O inner vibration of non bridge oxygen, around 1 000 cm-1 for Be—O outer vibration of non bridge oxygen, 685 cm-1 for Si—O—Si inner vibration of deformation, 400 cm-1 for O—Be—O outer vibration of bending, 390 cm-1 for Al—O outer vibration of deformation, 320 cm-1 for Al—O outer vibration of bending..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2175 (2014)
Theoretical Analysis of Saturated Spectral Line Shape of Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy
MA Wei-guang, TAN Wei, ZHAO Gang, LI Zhi-xin, FU Xiao-fang, DONG Lei, ZHANG Lei, YIN Wang-bao, and JIA Suo-tang
In the present paper a theoretical description of the line shapes of frequency modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) under saturated conditions is presented. Expressions for both Doppler broadened and Doppler free frequency modulated NICE-OHMS signals at their absoIn the present paper a theoretical description of the line shapes of frequency modulated noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS) under saturated conditions is presented. Expressions for both Doppler broadened and Doppler free frequency modulated NICE-OHMS signals at their absorption and dispersion phases are given. The modulation frequency, saturation parameter and frequency modulation index are set to 384 MHz, 10 and 0.2, respectively in the simulation. Based on the simulated line shape curves, in the absorption detection phase there are four sub Doppler structures existing in the spectral envelope of absorption signals of two sidebands, and in the dispersion phase there are five sub-Doppler structures existing in the spectral envelope of dispersion signals of carrier and two sidebands. The sub-Doppler structure originates from the fact that two counter propagating waves interact with the same group of molecules and one can act as a detecting beam and the other can act as a pumping beam. Therefore the sub-Doppler structure can appear at laser carrier and sidebands frequency and their middle frequencies of carrier and sidebands. Since NICE-OHMS absorption signal is only related to the absorption of sidebands the small saturation parameters of two sidebands can not saturate the Doppler broadened signal too much. Although the NICE-OHMS dispersion signal includes the dispersion of carrier and two sidebands, the amplitude of Doppler broadened signal does not have so much influence by saturation except for the Doppler free signal. Therefore NICE-OHMS technique is a good candidate for the high sensitive detection of gas medium but with high selectivity under the condition of low pressure. Finally the dependences of NICE-OHMS line shape on the detection phase and saturation parameter are simulated and analyzed, the results of which nicely agree with the existing experimental results. The researches on NICE-OHMS line shapes will help explain the phenomena of related experiment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2180 (2014)
Primary Investigation of Formation and Genetic Mechanism of Land Subsidence Based on PS-InSAR Technology in Beijing
LEI Kun-chao, CHEN Bei-bei, JIA San-man, WANG Shu-fang, and LUO Yong
The present paper adopts permanent scatterer interferometric synthetic aperture radar(PS-InSAR)technique to obtain land subsidence information in Beijing plain area. Then, combined with the time series of meteorological data, groundwater dynamic monitoring data, interferometric data and geological structure data, the fThe present paper adopts permanent scatterer interferometric synthetic aperture radar(PS-InSAR)technique to obtain land subsidence information in Beijing plain area. Then, combined with the time series of meteorological data, groundwater dynamic monitoring data, interferometric data and geological structure data, the formation and evolution mechanism of land subsidence were revealed. The results show that (1) Beijing regional land subsidence characteristics are obvious, more land subsidence funnel areas are interconnected, the settlement is influenced by rainfall recharge and exhibits seasonal fluctuation characteristics; (2) The land subsidence center and groundwater drawdown funnel centre are not fully consistent, unconfined aquifer and shallow confined aquifer are the major contribution factors and have greater impact on the land subsidence; (3) Land subsidence mainly occurred in the clay layer with a thickness of 50~70 m; (4) Land subsidence caused by tectonic controls is significant and the deformation gradient is great on both sides of the fault..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2185 (2014)
Comparison of Red Edge Parameters of Winter Wheat Canopy under Late Frost Stress
WU Yong-feng, HU Xin, Lv Guo-hua, REN De-chao, JIANG Wei-guo, and SONG Ji-qing
In the present study, late frost experiments were implemented under a range of subfreezing temperatures (-1～-9 ℃) by using a field movable climate chamber (FMCC) and a cold climate chamber, respectively. Based on the spectra of winter wheat canopy measured at noon on the first day after the frost experiments, red edge In the present study, late frost experiments were implemented under a range of subfreezing temperatures (-1～-9 ℃) by using a field movable climate chamber (FMCC) and a cold climate chamber, respectively. Based on the spectra of winter wheat canopy measured at noon on the first day after the frost experiments, red edge parameters REP, Dr, SDr, Drmin, Dr/Drmin and Dr/SDr were extracted using maximum first derivative spectrum method (FD), linear four-point interpolation method (FPI), polynomial fitting method (POLY), inverted Gaussian fitting method (IG) and linear extrapolation technique (LE), respectively. The capacity of the red edge parameters to detect late frost stress was explicated from the aspects of the early, sensitivity and stability through correlation analysis, linear regression modeling and fluctuation analysis. The result indicates that except for REP calculated from FPI and IG method in Experiment 1, REP from the other methods was correlated with frost temperatures (P<0.05). Thereinto, significant levels (P) of POLY and LE methods all reached 0.01. Except for POLY method in Experiment 2, Dr/SDr from the other methods were all significantly correlated with frost temperatures (P<0.01). REP showed a trend to shift to short-wave band with decreasing temperatures. The lower the temperature, the more obvious the trend is. Of all the REP, REP calculated by LE method had the highest correlation with frost temperatures which indicated that LE method is the best for REP extraction. In Experiment 1 and 2, only Drmin and Dr/Drmin calculated by FD method simultaneously achieved the requirements for the early (their correlations with frost temperatures showed a significant level P<0.01), sensitivity (absolute value of the slope of fluctuation coefficient is greater than 2.0) and stability (their correlations with frost temperatures always keep a consistent direction). Dr/SDr calculated from FD and IG methods always had a low sensitivity in Experiment 2. In Experiment 1, the sensitivity of Dr/SDr from FD was moderate and IG was high. REP calculated from LE method had a lowest sensitivity in the two experiments. Totally, Drmin and Dr/Drmin calculated by FD method have the strongest detection capacity for frost temperature, which will be helpful to conducting the research on early diagnosis of late frost injury to winter wheat..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2190 (2014)
Simulation of Pseudo Cross-Correlation Degraded by the Hyperspectral Imaging of Satellite Complex Motion
ZHANG Li-jun, CHANG Yue-e, TANG Yi, NAN Yi-bing, and GUO Qian
The present paper proposed a spectral degradation theory based on the point spread matrix, which is developed from the simulation algorithm of degradation based on differential dynamic spectral imaging for moving imaging. According to the eight neighborhood mixing model, considering the varying movement with time of thThe present paper proposed a spectral degradation theory based on the point spread matrix, which is developed from the simulation algorithm of degradation based on differential dynamic spectral imaging for moving imaging. According to the eight neighborhood mixing model, considering the varying movement with time of the satellite platform, the situation that different object pixel has different point spread matrix is corresponding to the concept of the pseudo cross-correlation theory. Thus, the pseudo cross-correlation degradation theory of moving spectral imaging is presented. In this method, the point spread matrix is constructed by the mean mixing ratio of eight neighborhoods, which can be calculated by the POS data on satellite using the differential imaging theory based on image motion matrix. When calculating the point spread matrix with the simulating POS data curve, we found out that the point spread matrix can be simplified according to the importance of mixing effect to reduce calculation. Then, the presentation and computing method of the pseudo cross-correlation degradation theory of moving spectral imaging is clearly articulated, and the result of degradation simulating and calculating is evaluated qualitatively and quantitatively from imaging dimension and spectral dimension respectively, and the similarity between the degradation image and the initial image is revealed using the SSIM parameter. The pseudo cross-correlation degradation theory of moving spectral imaging improves the existing problem of spectral imaging degradation based on the complex movement of satellite platform. The simulation results show that this kind of degradation theory is suitable for solving the problem of spectral imaging degradation based on the complex satellite platform movement completely..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2196 (2014)
Evaluation of Four Dark Object Atmospheric Correction Methods Based on ZY-3 CCD Data
GUO Hong, GU Xing-fa, XIE Yong, YU Tao, GAO Hai-liang, WEI Xiang-qin, and LIU Qi-yue
The present paper performed the evaluation of four dark-object subtraction(DOS) atmospheric correction methods based on 2012 Inner Mongolia experimental data. The authors analyzed the impacts of key parameters of four DOS methods when they were applied to ZY-3 CCD data. The results showed that (1) All four DOS methods The present paper performed the evaluation of four dark-object subtraction(DOS) atmospheric correction methods based on 2012 Inner Mongolia experimental data. The authors analyzed the impacts of key parameters of four DOS methods when they were applied to ZY-3 CCD data. The results showed that (1) All four DOS methods have significant atmospheric correction effect at band 1, 2 and 3. But as for band 4, the atmospheric correction effect of DOS4 is the best while DOS2 is the worst; both DOS1 and DOS3 has no obvious atmospheric correction effect. (2) The relative error (RE) of DOS1 atmospheric correction method is larger than 10% at four bands; The atmospheric correction effect of DOS2 works the best at band 1(AE (absolute error)=0.001 9 and RE=4.32%) and the worst error appears at band 4(AE=0.046 4 and RE=19.12%); The RE of DOS3 is about 10% for all bands. (3) The AE of atmospheric correction results for DOS4 method is less than 0.02 and the RE is less than 10% for all bands.Therefore,the DOS4 method provides the best accuracy of atmospheric correction results for ZY-3 image..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2203 (2014)
Characteristics Analysis of Human Tongue Reflectance Spectra
ZHAO Jing, LIU Ming, LU Xiao-zuo, and LI Gang
The present paper presents the spectroscopic analysis method. Eighty samples of spectra data of tongue parts with coating and without coating were collected by Usb4000 spectrometer of Ocean Optics, then comparing the spectra data of the different parts of tongue we found that there was a relation between the spectra chThe present paper presents the spectroscopic analysis method. Eighty samples of spectra data of tongue parts with coating and without coating were collected by Usb4000 spectrometer of Ocean Optics, then comparing the spectra data of the different parts of tongue we found that there was a relation between the spectra characteristics and tongue coating, and further analysis of the spectra data showed that there was a big difference between the two parts within the wavelength range between 500 and 600 nm. It was also found that the biggest differences appear when the wavelength is 579.39 nm, and at the same time, different colors of tongue coating were also compared, and the spectrum was also quite different because of different color and thickness of the tongue coating. The experiment results show that different color, thickness, and dryness of the human tongue coating lead to different spectral characteristics, and compared with the current colorimetric method of tongue characterization, spectral reflectance can reflect more physiological and pathological information. The experiment results also indicated that the different spectral characteristics of tongue property and tongue coating will be used for further separation of these two parts, and to provide an objective analysis index for tongue coating qualitative and quantitative analysis, so as to promote the objectivity of the TCM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2208 (2014)
Validation of HJ-1B Thermal Infrared Channels Onboard Radiometric Calibration Based on Spectral Response Differences
LIU Li, FU Qiao-yan, SHI Ting-ting, WANG Ai-chun, and ZHANG Xue-wen
Since HJ-1B was launched, 7 sets of blackbody data have been used to calculate onboard calibration coefficients, but the research work on the validation of coefficients is rare. According to the onboard calibration principle, calibration coefficients of HJ-1B thermal infrared channel on Sep 14th, 2009 were calculated wSince HJ-1B was launched, 7 sets of blackbody data have been used to calculate onboard calibration coefficients, but the research work on the validation of coefficients is rare. According to the onboard calibration principle, calibration coefficients of HJ-1B thermal infrared channel on Sep 14th, 2009 were calculated with the half-width, moments and look-up table methods. MODIS was selected for the reference sensor, and algorithms of spectral match were improved between the HJ-1B thermal infrared channel and MODIS 31, 32 channels based on the spectral response divergence. The relationship of top of atmosphere (TOA) radiance between the remote sensors was calculated, based on which the surface leaving brightness temperature was calculated by Planck function to validate the brightness temperature calculated through the onboard calibration coefficients. The equivalent brightness temperature calculated by spectral response divergence method is 285.97 K, and the inversion brightness temperature calculated by half-width, moments and look-up table methods is 288.77, 274.52 and 285.97 K respectively. The difference between the inversion brightness temperature and the equivalent brightness temperature is 2.8, -11.46 and 0.02 K, respectively, which demonstrate that onboard calibration coefficients calculated by the look-up table method has better precision and feasibility..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2212 (2014)
Hyperspectral Image Classification Based on 3-D Gabor Filter and Support Vector Machines
FENG Xiao, XIAO Peng-feng, LI Qi, LIU Xiao-xi, and WU Xiao-cui
A three-dimensional Gabor filter was developed for classification of hyperspectral remote sensing image. This method is based on the characteristics of hyperspectral image and the principle of texture extraction with 2-D Gabor filters. Three-dimensional Gabor filter is able to filter all the bands of hyperspectral imagA three-dimensional Gabor filter was developed for classification of hyperspectral remote sensing image. This method is based on the characteristics of hyperspectral image and the principle of texture extraction with 2-D Gabor filters. Three-dimensional Gabor filter is able to filter all the bands of hyperspectral image simultaneously, capturing the specific responses in different scales, orientations, and spectral-dependent properties from enormous image information, which greatly reduces the time consumption in hyperspectral image texture extraction, and solve the overlay difficulties of filtered spectrums. Using the designed three-dimensional Gabor filters in different scales and orientations, Hyperion image which covers the typical area of Qi Lian Mountain was processed with full bands to get 26 Gabor texture features and the spatial differences of Gabor feature textures corresponding to each land types were analyzed. On the basis of automatic subspace separation, the dimensions of the hyperspectral image were reduced by band index (BI) method which provides different band combinations for classification in order to search for the optimal magnitude of dimension reduction. Adding three-dimensional Gabor texture features successively according to its discrimination to the given land types, supervised classification was carried out with the classifier support vector machines (SVM). It is shown that the method using three-dimensional Gabor texture features and BI band selection based on automatic subspace separation for hyperspectral image classification can not only reduce dimensions, but also improve the classification accuracy and efficiency of hyperspectral image..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2218 (2014)
Study on the Live State of Pieris Rapaes Using Near Infrared Hypserspectral Imaging Technology
SONG Ge-lian, YU Jun-lin, LIU Fei, HE Yong, CHEN Dan, and MO Wang-cheng
Near-infrared hypserspectral imaging technology was applied for the discrimination of a variety of life states, the judgment of being alive or death. Discrimination models were built based on spectral data of pieris rapaes acquired during different life states. The wavelengths from 951.5 to 1 649.2 nm were used for anaNear-infrared hypserspectral imaging technology was applied for the discrimination of a variety of life states, the judgment of being alive or death. Discrimination models were built based on spectral data of pieris rapaes acquired during different life states. The wavelengths from 951.5 to 1 649.2 nm were used for analysis after the removal of spectral region with obvious noises at the beginning and the end. And the spectra data of 951.5～1 649.2 nm were preprocessed by different pretreatment methods. To discriminate the state of being alive or death of pieris rapaes, discrimination models were built based on the spectral data processed by different pretreatment methods. Results showed that the discriminant accuracy can approach or attain 100%. Thus the method was proved to be useful for the discrimination of the state of being alive or death of pieris rapaes. After the spectral data were preprocessed by moving average (MA) algorithm, 17 characteristic wavelengths were extracted based on weighted regression coefficient (Bw) and 20 were extracted based on successive projections algorithm (SPA) to identify the state of being alive or death of pieris rapaes. Four classification methods based on characteristic wavelengths, including partial least squares-discriminant analysis (PLS-DA), K-nearest neighbor algorithm (KNN), back propagation neural network (BPNN) and support vector machine (SVM) were used to build discriminant models for identifying the state of being alive or death of pieris rapaes. The discriminant accuracy all can approach or attain 100%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2225 (2014)
An Algorithm of Spectral Minimum Shannon Entropy on Extracting Endmember of Hyperspectral Image
YANG Ke-ming, LIU Shi-wen, WANG Lin-wei, YANG Jie, SUN Yang-yang, and HE Dan-dan
It’s significant to study the algorithm of endmember extraction, which is the key for pixel unmixing, in the fields of feature identification, abundance inversion, quantitative remote sensing and so on. Based on the theory of shannon entropy and Gaussian distribution function, a new algorithm, named spectral minimum shIt’s significant to study the algorithm of endmember extraction, which is the key for pixel unmixing, in the fields of feature identification, abundance inversion, quantitative remote sensing and so on. Based on the theory of shannon entropy and Gaussian distribution function, a new algorithm, named spectral minimum shannon entropy (SMSE) method for extracting endmembers of hyperspectral images, is proposed in the present paper after analyzing the characteristics of spectra of the hyperspectral images. This algorithm was applied to extract the endmembers of an AVRIRS hyperspectral image, it was found that these extracted endmember spectra have higher precision by matching with the spectral library of United States Geological Survey(USGS). At the same time, it was also found that the SMSE algorithm has better efficiency and accuracy for extracting endmember spectra through comparing and analyzing comprehensively the results of endmember extraction of the experimental data by using the methods of SMSE, pixel purity index(PPI), sequential maximum angle convex cone(SMACC) and so on. In addition, the SMACC and SMSE are used to extract the endmembers in a Hyperion hyperspectral image, and it is concluded that the results of the SMSE is better than the SMACC’s. Thus, the SMSE algorithm can be thought to have a certain degree of universal applicability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2229 (2014)
A Novel Method Based on Y-Shaped Cotton-Polyester Thread Microfluidic Channel
WANG Lu, SHI Yan-ru, and YAN Hong-tao
A novel method based on Y-shaped microfluidic channel was firstly proposed in this study. The microfluidic channel was made of two cotton-polyester threads based on the capillary effect of cotton-polyester threads for the determination solutions. A special device was developed to fix the Y-shaped microfluidic channel bA novel method based on Y-shaped microfluidic channel was firstly proposed in this study. The microfluidic channel was made of two cotton-polyester threads based on the capillary effect of cotton-polyester threads for the determination solutions. A special device was developed to fix the Y-shaped microfluidic channel by ourselves, through which the length and the tilt angle of the channel can be adjusted as requested. The spectrophotometry was compared with Scan-Adobe Photoshop software processing method. The former had a lower detection limit while the latter showed advantages in both convenience and fast operations and lower amount of samples. The proposed method was applied to the determination of nitrite. The linear ranges and detection limits are 1.0~70 μmol·L-1, 0.66 μmol·L-1 (spectrophotometry) and 50~450 μmol·L-1, 45.10 μmol·L-1 (Scan-Adobe Photoshop software processing method) respectively. This method has been successfully used to the determination of nitrite in soil samples and moat water with recoveries between 96.7% and 104%. It was proved that the proposed method was a low-cost, rapid and convenient analytical method with extensive application prospect..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2234 (2014)
Progress in the Application of Laser Ablation ICP-MS to Surface Microanalysis in Material Science
ZHANG Yong, JIA Yun-hai, CHEN Ji-wen, SHEN Xue-jing, LIU Ying, ZHAO Lei, LI Dong-ling, HANG Peng-cheng, ZHAO Zhen, FAN Wan-lun, and WANG Hai-zhou
In the present paper, apparatus and theory of surface analysis is introduced, and the progress in the application of laser ablation ICP-MS to microanalysis in ferrous, nonferrous and semiconductor field is reviewed in detail. Compared with traditional surface analytical tools, such as SEM/EDS (scanning electron microscIn the present paper, apparatus and theory of surface analysis is introduced, and the progress in the application of laser ablation ICP-MS to microanalysis in ferrous, nonferrous and semiconductor field is reviewed in detail. Compared with traditional surface analytical tools, such as SEM/EDS (scanning electron microscopy/energy dispersive spectrum), EPMA (electron probe microanalysis analysis), AES (auger energy spectrum), etc. the advantage is little or no sample preparation, adjustable spatial resolution according to analytical demand, multi-element analysis and high sensitivity. It is now a powerful complementary method to traditional surface analytical tool. With the development of LA-ICP-MS technology maturing, more and more analytical workers will use this powerful tool in the future, and LA-ICP-MS will be a super star in elemental analysis field just like LIBS (Laser-induced breakdown spectroscopy)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2238 (2014)
Study on the Multivariate Quantitative Analysis Method for Steel Alloy Elements Using LIBS
GU Yan-hong, LI Ying, TIAN Ye, and LU Yuan
Quantitative analysis of steel alloys was carried out using laser induced breakdown spectroscopy ( LIBS ) taking into account the complex matrix effects in steel alloy samples. The laser induced plasma was generated by a Q-switched Nd∶YAG laser operating at 1 064 nm with pulse width of 10 ns and repeated frequency of 1Quantitative analysis of steel alloys was carried out using laser induced breakdown spectroscopy ( LIBS ) taking into account the complex matrix effects in steel alloy samples. The laser induced plasma was generated by a Q-switched Nd∶YAG laser operating at 1 064 nm with pulse width of 10 ns and repeated frequency of 10 Hz. The LIBS signal was coupled to the echelle spectrometer and recorded by a high sensitive ICCD detector. To get the best experimental conditions, some parameters, such as the detection delay, the CCD's integral gate width and the detecting position from the sample surface, were optimized. The experimental results showed that the optimum detection delay time was 1.5μs, the optimal CCD's integral gate width was 2 μs and the best detecting position was 1.5 mm below the alloy sample’s surface. The samples used in the experiments are ten standard steel alloy samples and two unknown steel alloy samples. The quantitative analysis was investigated with the optimum experimental parameters. Elements Cr and Ni in steel alloy samples were taken as the detection targets. The analysis was carried out with the methods based on conditional univariate quantitative analysis, multiple linear regression and partial least squares (PLS) respectively. It turned out that the correlation coefficients of calibration curves are not very high in the conditional univariate calibration method. The analysis results were obtained with the unsatisfied relative errors for the two predicted samples. So the conditional univariate quantitative analysis method can't effectively serve the quantitative analysis purpose for multi-components and complex matrix steel alloy samples. And with multiple linear regression method, the analysis accuracy was improved effectively. The method based on partial least squares (PLS) turned out to be the best method among all the three quantitative analysis methods applied. Based on PLS, the correlation coefficient of calibration curve for Cr is 0.981 and that for Ni is 0.995. The concentrations of Cr and Ni in two target samples were determined using PLS calibration method, and the relative errors for the two unknown steel alloy samples are lower than 6.62% and 1.49% respectively. The obtained results showed that in the quantitative analysis of steel alloys, the matrix effect would be reduced effectively and the quantitative analysis accuracy would be improved by the PLS calibration method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2244 (2014)
Determination of Multi-Element Contents in Gypsum by ICP-AES
GUO Zhong-bao, BAI Yong-zhi, CUI Jin-hua, MEI Yi-fei, and MA Zhen-zhu
The content of multi-element in gypsum was determined by ICP-AES. The sample was pretreated by acid-soluble method or alkali-fusion method. Acid-soluble method is suitable for the determination of CaO, SO3, Al2O3, Fe2O3, MgO, K2O, Na2O, TiO2, P2O5, MnO, SrO and BaO. Alkali-fusion method is suitable for the determinatioThe content of multi-element in gypsum was determined by ICP-AES. The sample was pretreated by acid-soluble method or alkali-fusion method. Acid-soluble method is suitable for the determination of CaO, SO3, Al2O3, Fe2O3, MgO, K2O, Na2O, TiO2, P2O5, MnO, SrO and BaO. Alkali-fusion method is suitable for the determination of CaO, SO3, SiO2, Al2O3, Fe2O3, MgO, TiO2, P2O5, MnO, SrO, BaO and B2O3. Different series standard solutions were prepared considering the properties and content of elements and solution matrix. The limit of detection and quantification were confirmed for each element under their best analysis spectral lines. The recoveries of the two pretreatment methods were from 93% to 110%, besides that for TiO2 was 81%～87% as pretreated by acid-soluble method. All RSDs(n=6)of tests were from 0.70%～3.42%. The accuracies of CaO and SO3 with ICP-AES method were less than the chemical analysis method. The determination of CaO and SO3 with ICP-AES method is only suitable for the case of low accuracy requirement. The results showed that the method can be used for the determination of multi-element contents in gypsum, with simple operation, fast analysis and reliable results. Total elements can be analysed with both acid-soluble method and alkali-fusion method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2250 (2014)
Cloud Point Extraction for Determination of Mercury in Chinese Herbal Medicine by Hydride Generation Atomic Fluorescence Spectrometry with Optimization Using Box-Behnken Design
WANG Mei, LI Shan, ZHOU Jian-dong, XU Ying, LONG Jun-biao, and YANG Bing-yi
Cloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by hydride generation-atomic fluorescence spectrometry (HG-AFS). Hg2+ was reacted with dithizone to form hydrophobic chelate under the condition of pH. Using Triton X-114, as surfactaCloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by hydride generation-atomic fluorescence spectrometry (HG-AFS). Hg2+ was reacted with dithizone to form hydrophobic chelate under the condition of pH. Using Triton X-114, as surfactant, chelate was quantitatively extracted into small volume of the surfactant-rich phase by heating the solution in a water bath for 15 min and centrifuging. Four variables including pH, dithizone concentration, Triton X-114 concentration and equilibrium temperature (T) showed the significant effect on extraction efficiency of total Hg evaluated by single-factor experiment, and Box-Behnken design and response surface methodology were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum extraction efficiency. The results showed that the binomial was used to fit the response to experimental levels of each variable. ALL linear, quadratic terms of four variables, and interactions between pH and Trion X-114, pH and dithizone affected the response value(extraction efficiency) significantly at 5% level. The optimum extraction conditions were as follows: pH 5.1, Triton X-114 concentration of 1.16 g·L-1, dithizone concentration of 4.87 mol·L-1, and T 58.2 ℃, the predicted value of fluorescence was 4 528.74 under the optimum conditions, and the experimental value had only 2.1% difference with it. Under the conditions, fluorescence was linear to mercury concentration in the range of 1～5 μg·L-1. The limit of detection obtained was 0.012 47 μg·L-1 with the relative standard deviations (R. S. D.) for six replicate determinations of 1.30%. The proposed method was successfully applied to determination of Hg in morindae Radix, Andrographitis and dried tangerine samples with the recoveries of 95.0%~100.0%. Apparently Box - Behnken design combined with response surface analysis method was considered to be well used for optimization of the cloud point extraction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2254 (2014)
Analysis of Arsenic Speciation in Food Condiments Based on the Online Trapping/Separation Coupling System
YUAN Chun-gang, JIANG Wan-ping, ZHU Tao, YUAN Bo, and SONG Xiao-wei
An online coupling system based on gas chromatography-hydride generation with atomic fluorescence spectrometry (GC-HG-AFS) for the analysis of arsenic species in food seasoning(soy sauce and vinegar) was developed. With absorbent cotton as separation medium, the volatile arsenic species released from the samples were cAn online coupling system based on gas chromatography-hydride generation with atomic fluorescence spectrometry (GC-HG-AFS) for the analysis of arsenic species in food seasoning(soy sauce and vinegar) was developed. With absorbent cotton as separation medium, the volatile arsenic species released from the samples were cold trapped online by liquid nitrogen. Then, the baseline separation of the volatile arsenic species was achieved at the room temperature and the arsenic species were sensitively detected by atomic fluorescence spectrophotometer. The experimental conditions such as flow rates of carrier gas (He), acid type and concentration, reducing reagent concentration and reaction time were discussed. Under the optimum conditions, the limit of detection for As(Ⅲ), As(Ⅴ), MMA(Ⅴ) and DMA(Ⅴ) was 0.2, 0.2, 0.3 and 0.8 ng·mL-1, respectively. The recoveries of As(Ⅲ), As(Ⅴ), MMA(Ⅴ) and DMA(Ⅴ) in soy sauce and vinegar were 93.07%～103.54%. Compared with the traditional liquid chromatography separation algorithm, the method was rapid, sensitive without any complex sample pretreatment. It was suitable and practical for detection of arsenic especially inorganic arsenic in food seasoning..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2259 (2014)
Analysis of Dissolution Characteristics and Content of Metal Elements in Scutellaria Baicalensis
LI Hua, LIU Jing, FU Mei-hong, KANG Chen, FANG Jing, and YANG Bin
ICP-OES analytical technique was used to determine the contents of Ca, Mg, Cu, Zn, Fe and Mn in S. baicalensis from different origins, and the dissolution characteristics and the contents of 6 elements were analyzed. There were significant differences in the contents among the prepared medical materials (pCa>Fe>MICP-OES analytical technique was used to determine the contents of Ca, Mg, Cu, Zn, Fe and Mn in S. baicalensis from different origins, and the dissolution characteristics and the contents of 6 elements were analyzed. There were significant differences in the contents among the prepared medical materials (p<0.05) and their water extraction also differed significantly. The results showed that there was no relationship on the contents of the 6 elements between in the prepared medical materials and in their water extraction. In the prepared medical materials, the contents of the elements were characterized as Mg>Ca>Fe>Mn>Zn>Cu, and the contents in the water extraction was rated from high to low as Mg, Ca, Mn, Zn, Fe and Cu. Most of the measured samples demonstrated lower Ca/Mg, higher Fe/Mn and lower Cu/Zn values, and these ratios were in relation to some efficacy of S. baicalensis, such as anti-hypertensive, anti-tumor activities. The results will provide a scientific basis for further enriching and developing the multi-index system for the quality evaluation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2264 (2014)
X-Ray Diffraction (XRD) and Near Infrared Spectrum(NIR) Analysis of the Soil Overlying the Bairendaba Deposit of the Inner Mongolia Grassland
LUO Song-ying, CAO Jian-jin, and WU Zheng-quan
The soil samples uniformly overlying the Bairendaba deposit of the Inner Mongolia grassland were collected, and analyzed with X-ray diffraction (XRD) and near infrared spectrum (NIR), for exploring the origins of the soil from the grassland mining area and the relationship with the underground rock. The results show thThe soil samples uniformly overlying the Bairendaba deposit of the Inner Mongolia grassland were collected, and analyzed with X-ray diffraction (XRD) and near infrared spectrum (NIR), for exploring the origins of the soil from the grassland mining area and the relationship with the underground rock. The results show that the samples consist of quartz, graphite, carbonate, hornblende, mica, chlorite, montmorillonite, illite, berlinite, diaspore, azurite, hematite, etc. These indicate that the soil samples were not only from the weathering products of the surface rock, but also from the underground rock mass and the alteration of the wall rock. The azurite and the hematite contained in the soil, mainly coming from the oxidation zone of the ore-bodies, can be used as the prospecting marks. The alteration mineral assemblage is mainly chlorite-illite-montmorillonite and it experienced the alteration process of potassic alteration→silicification→carbonatization→silk greisenization→clayization. Also, the wall rock alteration and the physical weathering processes can be accurately restored by analyzing the combination of the alteration minerals, which can provide important reference information for the deep ore prospecting and the ore deposit genesis study, improving the rate of the prospecting. The XRD and NIR with the characteristics of the economy and quickness can be used for the identification of mineral composition of soil, and in the study of mineral and mineral deposits. Especially, NIR has its unique superiority, that is, its sample request is low, and it can analyze a batch of samples quickly. With the development of INR, it will be more and more widely applied in geological field, and can play an important role in the ore exploration..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2268 (2014)
Research on Characteristics of Soil Clay Mineral Evolution in Paddy Field and Dry Land by XRD Spectrum
ZHANG Zhi-dan, LI Qiao, LUO Xiang-li, JIANG Hai-chao, ZHENG Qing-fu, ZHAO Lan-po, and WANG Ji-hong
The present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed tThe present paper took the typical saline-alkali soil in Jilin province as study object, and determinated the soil clay mineral composition characteristics of soil in paddy field and dry land. Then XRD spectrum was used to analyze the evolutionary mechanism of clay mineral in the two kinds of soil. The results showed that the physical and chemical properties of soil in paddy field were better than those in dry land, and paddy field would promote the weathering of mineral particles in saline-alkali soil and enhance the silt content. Paddy field soil showed a strong potassium-removal process, with a higher degree of clay mineral hydration and lower degree of illite crystallinity. Analysis of XRD spectrum showed that the clay mineral composition was similar in two kinds of soil, while the intensity and position of diffraction peak showed difference. The evolution process of clay mineral in dry land was S/I mixture→vermiculite, while in paddy field it was S/I mixture→vermiculite→kaolinite. One kind of hydroxylated 'chlorite' mineral would appear in saline-alkali soil in long-term cultivated paddy field. Taking into account that the physical and chemical properties of soil in paddy field were better then those in dry land, we could know that paddy field could help much improve soil structure, cultivate high-fertility soil and improve saline-alkali soil. This paper used XRD spectrum to determine the characteristics of clay minerals comprehensively, and analyzed two kinds of land use comparatively, and was a new perspective of soil minerals study..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2273 (2014)
A New Method of Sparse Feature Extraction for Stellar Spectra
LU Yu, LI Xiang-ru, YANG Tan, and WANG Yong-jun
The authors propose a novel method of feature extraction for stellar spectra parameterization. The basic procedures are: First, stellar spectra are decomposed by multi-scale Harr wavelet and the coefficients with high-frequency are rejected. Secondly, the optimal features are detected by the lasso algorithm. Finally, wThe authors propose a novel method of feature extraction for stellar spectra parameterization. The basic procedures are: First, stellar spectra are decomposed by multi-scale Harr wavelet and the coefficients with high-frequency are rejected. Secondly, the optimal features are detected by the lasso algorithm. Finally, we input the optimal feature vector to non-parametric regression model to estimate the atmospheric parameters. Haar wavelet can remove the high-frequency noise from the stellar spectrum. Lasso algorithm can further compress data by analyzing their significance on parameterization and removing redundancy. Experiments show that the proposed Haar+lasso method improves the accuracy and efficiency of the estimation. The authors used this scheme to estimate the atmospheric parameters from a subsample of some 40 000 stellar spectra from SDSS. The accuracies of our predictions (mean absolute errors) for each parameter are 0.007 1 dex for log Teff, 0.225 2 dex for log g, and 0.199 6 dex for ［Fe/H］. Compared with the results of the existing literature, this scheme can derive more accurate atmospheric parameters..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2279 (2014)
Quenched Fluorescein: A Reference Dye for Instrument Response Function of TCSPC
PAN Hai-feng, DING Jing-xin, LIANG Rong-rong, TAO Zhan-dong, LIU Meng-wei, ZHANG San-jun, and XU Jian-hua
Measuring the instrument response function (IRF) and fitting by reconvolution algorithms are routines to improve time resolution in fluorescence lifetime measurements. Iodide ions were successfully used to quench the fluorescence of fluorescein in this study. By systematically adding saturated NaI water solution in basMeasuring the instrument response function (IRF) and fitting by reconvolution algorithms are routines to improve time resolution in fluorescence lifetime measurements. Iodide ions were successfully used to quench the fluorescence of fluorescein in this study. By systematically adding saturated NaI water solution in basic fluorescein solution, the lifetimes of fluorescein were reduced from 4 ns to 24 ps. The quenched lifetime of fluorescein obtained from the analysis of Time-Correlated Single Photon Counting (TCSPC) measurement agrees well with that from femtosecond frequency up-conversion measurement. In time resolved excitation spectra measurements, the IRF should be measured at various detection wavelengths providing scattring materials are used. This study could not only reduce the complexity of IRF measurement, but also avoid the existing color effect in system. This study should have wide applications in time resolved fluorescence spectroscopy and fluorescence lifetime imaging..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2284 (2014)
Full-Field and Automatic Methodology of Spectral Calibration for PGP Imaging Spectrometer
SUN Ci, Bayanheshig, CUI Ji-cheng, PAN Ming-zhong, LI Xiao-tian, and TANG Yu-guo
In order to analyze spectral data quantitatively which is obtained by prism-grating- prism imaging spectrometer, spectral calibration is required in order to determine spectral characteristics of PGP imaging spectrometer, such as the center wavelength of every spectral channel, spectral resolution and spectral bending.In order to analyze spectral data quantitatively which is obtained by prism-grating- prism imaging spectrometer, spectral calibration is required in order to determine spectral characteristics of PGP imaging spectrometer, such as the center wavelength of every spectral channel, spectral resolution and spectral bending. A spectral calibration system of full field based on collimated monochromatic light method is designed. Spherical mirror is used to provide collimated light, and a freely sliding and rotating folding mirror is adopted to change the angle of incident light in order to realize full-field and automatic calibration of imaging spectrometer. Experiments of spectral calibration have been done for PGP imaging spectrometer to obtain parameters of spectral performance, and accuracy analysis combined with the structural features of the entire spectral calibration system have been done. Analysis results indicate that spectral calibration accuracy of the calibration system reaches 0.1 nm, and the bandwidth accuracy reaches 1.3%. The calibration system has merits of small size, better commonality, high precision and so on, and because of adopting the control of automation, the additional errors which are caused by human are avoided. The calibration system can be used for spectral calibration of other imaging spectrometers whose structures are similar to PGP..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2289 (2014)
Design of Inhalable Particulate Matters Measurement Based on the Mie Scattering Extinction
ZHANG Peng, LIU Lu-lu, LI Chuan-liang, QIU Xuan-bing, and WEI Ji-lin
The concentration of inhalable particle is an important indicator in atmospheric environment monitor. Based on Mie scattering extinction, a precise testing instrument which can measure the concentration of inhalable particles at the atmospheric was designed by three-wavelength method in combination with the algorithm oThe concentration of inhalable particle is an important indicator in atmospheric environment monitor. Based on Mie scattering extinction, a precise testing instrument which can measure the concentration of inhalable particles at the atmospheric was designed by three-wavelength method in combination with the algorithm of distributed function. The dependence of extinction index on the spectrum was calculated based on Mie scattering theory in this article. Furthermore, the signal of time domain is integrated in the data processing to reduce the effect of error caused by multi-peak of spectra. The PM2.5 and PM10 were collected simultaneously in particle selection. Three different wave-lengths of lasers were coupled into an optical fiber by coupler (3in1) and passed through the sample cell. The attenuated light was detected by a PIN. Output of the detector was converted, amplified, displayed and stored by electronic system. Finally, the data were transmitted and shared in network through the 3G wireless module. The average particle size and concentration of inhalable particles were measured by this device at the same time. The technical specifications of the detector were verified by experiment, the experimental results indicate that the detection sensitivity of the system is 0.01 μg·m-3, the responsive time of system is approximately 90 s and it is suitable for measuring particulate matter concentrations of atmosphere..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2298 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 1 (2014)
Research Articles
Application of THz Technology to Nondestructive Detection of Agricultural Product Quality
JIANG Yu-ying, GE Hong-yi, LIAN Fei-yu, ZHANG Yuan, and XIA Shan-hong
With recent development of THz sources and detector, applications of THz radiation to nondestructive testing and quality control have expanded in many fields, such as agriculture, safety inspection and quality control, medicine, biochemistry, communication etc. Compared with other detection technique, being a new kind With recent development of THz sources and detector, applications of THz radiation to nondestructive testing and quality control have expanded in many fields, such as agriculture, safety inspection and quality control, medicine, biochemistry, communication etc. Compared with other detection technique, being a new kind of technique, THz radiation has low energy, good perspectivity, and high signal-to-noise ratio, and thus can obtain physical, chemical and biological information. This paper first introduces the basic concept of THz radiation and the major properties, then gives an extensive review of recent research progress in detection of the quality of agricultural products via THz technique, analyzes the existing shortcomings of THz detection and discusses the outlook of potential application, finally proposes the new application of THz technique to detection of quality of stored grain..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2047 (2014)
Design and Study of Middle Infrared Spectrum System with Variational Field of View
BAI Yu, XING Ting-wen, JIANG Ya-dong, and FENG Cheng
In order to track and capture target at the same time with a set of equipment, a middle infrared spectrum variational field of view(fov) detection system with a large focal plane array was designed for a 640×512 novel large focal plane array infrared detector with the picture element size of 15 m×15 m. The spIn order to track and capture target at the same time with a set of equipment, a middle infrared spectrum variational field of view(fov) detection system with a large focal plane array was designed for a 640×512 novel large focal plane array infrared detector with the picture element size of 15 m×15 m. The spectrum range was 3.7～4.8 m, F number was 4.0, narrow FOV and wide FOV was 0.45 and 0.90 respectively. The manner of variational FOV was accomplished by pitching two lenses into the narrow FOV system layout with mechanism framework. Reimaging technology not only minished the diameter of front fixed group, but also met 100% cold shield efficiency to minish stray light into the infrared detector. Two common infrared materials Ge and Si were used in the variational FOV detection system. The aspheric technology was used in order to correct the off axis aberration and higher order aberration and assure the fixedness of image plane. At the spatial frequency 33 lp·mm-1, the modulation transfer function(MTF) was above 0.2 for both the narrow FOV and wide FOV. Moreover, the distortion is below 0.5%. The middle infrared spectrum variational FOV detection system has excellent image. The image quality of the middle infrared spectrum variational field of view detection system changed little in the working temperature range -35～55 ℃..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 8, 2293 (2014)
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