Journals >Spectroscopy and Spectral Analysis
Contents
2014
Volume: 34 Issue 11
57 Article(s)
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Research Article
Measurement and Application of CO2 Spectroscopic Parameters near 2.0 μm
SUN Ming-guo, MA Hong-liang, CAO Zhen-song, LIU Qiang, WANG Gui-shi, CHEN Wei-dong, and GAO Xiao-ming
The accuracy of absorption spectral parameters is very important for the trace gas measurement based on absorption spectroscopy techniques, especially for the isotopic abundance measurement of gas molecules. For some of the applications, spectral parameters listed in HITRAN database were used to retrieve the trace gas The accuracy of absorption spectral parameters is very important for the trace gas measurement based on absorption spectroscopy techniques, especially for the isotopic abundance measurement of gas molecules. For some of the applications, spectral parameters listed in HITRAN database were used to retrieve the trace gas concentration. However, these parameters have uncertainty, in order to validate spectroscopic parameters near 2.0 μm of CO2 lines, which are to be used in detecting the CO2 concentration and isotopic abundance, spectra of those lines were recorded at room temperature using a distributed feed-back (DFB) diode laser. The recorded absorption spectra were fitted to Voigt profile. Line position, intensity, self-broadening coefficient and N2-broadening coefficient were deduced from those data. The results show a good consistency in comparison with those listed in HITRAN2012 database. The discrepancy of most line intensities and self-broadening coefficients are less than 2%. The CO2 concentration and δ(13CO2)in real atmosphere inside laboratory are 440 ppm and -9‰ respectively. These results provide a reliable basis for real time and on line detecting the CO2 concentration and δ(13CO2)in the wavelength range..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2881 (2014)
Collisional Relaxation between Highly Vibrationally Excited Na2 and Ar, and H2
WANG Shu-ying, LI Jia-ling, DAI Kang, and SHEN Yi-fan
Energy transfer rate constants were measured for excited rovibrational levels of Na2 (X1Σ+g). Stimulated emission pumping was used to excited the levels ν=33～51, J=11 via A-X transition. Laser induced fluorescence was used to follow the collision dynamics. Energy transfer processes induced by collisions with Ar and H2 Energy transfer rate constants were measured for excited rovibrational levels of Na2 (X1Σ+g). Stimulated emission pumping was used to excited the levels ν=33～51, J=11 via A-X transition. Laser induced fluorescence was used to follow the collision dynamics. Energy transfer processes induced by collisions with Ar and H2 were investigated. The decay curves for the parent level populations gave good fits to single exponential function. At ν=33～51, the total transfer rate constants increase linearly with vibrational quantum number. Parameterized expressions for the (48, 11)- to -(47, J) rate constants were fitted to the fractional populations of the satellite lines. This produced sets of relative rate constants. Absolute rate constants were then obtained by normalizing the sums of the relative rate constants to the total removal rate constants. For Na2(ν)+Ar, no multiquantum vibrational transfer was detected. For Na2(ν)+H2, a significant fraction of the initial population of highly vibrationally excited Na2(X ν=48) relaxes to lower vibrational level (Δν=-5). The time scale is much shorter than the known collisional lifetimes of the intervening vibrational levels and thus a sequential single-quantum relaxation mechanism can be explicitly ruled out. For ν=48, at least 40% of the initially prepared population, undergoes multiquantum vibrational relaxation. We discuss possible explanations of this result..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2887 (2014)
Structural, Morphological and Optical Properties of PbI2 Thick Films
YANG Ding-yu, ZHU Xing-hua, SUN Hui, HAO Dong, LI Xu, and GAO Xiu-ying
In the present paper, the structural, morphological and optical properties of PbI2 thick films prepared by close-spaced sublimation technique were investigated. It was found that the thickness of PbI2 films decreased from 1 000 μm to 220 μm with the increase in the sublimation source temperature. X-ray diffraction (XRDIn the present paper, the structural, morphological and optical properties of PbI2 thick films prepared by close-spaced sublimation technique were investigated. It was found that the thickness of PbI2 films decreased from 1 000 μm to 220 μm with the increase in the sublimation source temperature. X-ray diffraction (XRD) pattern shows that the thick films are polycrystalline hexagonal structure with preferred growth orientation of (002) plane, and their grain size, dislocation density and growth stress are closely related to the source temperature. Images of scanning electron microscopy (SEM) reveal the accumulation of hexagonal plate-like particles which constitute the samples, and the particles with a diameter of 248 μm and a thickness of 32.7 μm, exhibit clearly layered structure. By spectrum fitting using Gauss function, the Raman spectra show a shift of about 147, 169, 217 and 210 cm-1 respectively, the first three peaks correspond to the longitudinal optical vibrations (LO) mode in 4H-PbI2 crystal, while the last peak originate from a vibration pattern associated with SnO2 in substrate. Raman peak of 147 cm-1 changes significantly with the increases in source temperature, and a dramatic decrease in peak intensity with broadening peak width occurred when the source temperature increased up to 225 ℃ or more. Under 340 nm excitation at room temperature, several weak photoluminescence peaks of PbI2 samples which associated with defects and exciton recombination near 2.25, 2.57 and 2.64 eV were observed. Given a comprehensive consideration of structural and spectral characterization results, PbI2 thick films with a thickness of about 659 μm deposited at a source temperature of 200 ℃ achieves the best crystalline quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2892 (2014)
Nondestructive Evaluation of Wheat Quality Using Terahertz Time Domain Spectroscopy
GE Hong-yi, JIANG Yu-ying, LIAN Fei-yu, ZHANG Yuan, and XIA Shan-hong
Terahertz time-domain spectroscopy (THz-TDS) is used to investigate the spectra properties of the wheat kernel with various deterioration degrees in the frequency range of 0.2～1.6 THz. The absorption coefficient and refractive index of normal, worm-eaten, moldy and sprouting wheat kernel were calculated. Comparison of Terahertz time-domain spectroscopy (THz-TDS) is used to investigate the spectra properties of the wheat kernel with various deterioration degrees in the frequency range of 0.2～1.6 THz. The absorption coefficient and refractive index of normal, worm-eaten, moldy and sprouting wheat kernel were calculated. Comparison of the experimental data, clearly indicates that changes in the absorption coefficient and refractive index are recorded, different wheat samples have different optical parameters. The absorption coefficient of normal wheat sample is more obvious and higher than others; refractive index increases as the frequency increases. THz-TDS can be employed to evaluate the quality of wheat kernel nondestructively. The results show that THz-TDS is a promising and new experimental method for quality analyses and control for agricultural production detection. This study will provide an important guidance for nondestructive detecting the quality of stored-grain..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2897 (2014)
Study of the Last Glacial Loess-Like Deposits in the Coastal Area of South China with Diffuse Reflectance Spectroscopy and Laser Particle Size Analysis
WANG Jing, CHEN Zhen, and CHEN Guo-neng
Newly discovered yellow silt widely distributed in the coastal area of south China was analyzed using diffuse reflectance spectroscopy (DRS) and laser particle size(LPS)methods in the present paper. The authors take the lead in trying to synthetically judge the depositional enviro nment, transporting agent and forming Newly discovered yellow silt widely distributed in the coastal area of south China was analyzed using diffuse reflectance spectroscopy (DRS) and laser particle size(LPS)methods in the present paper. The authors take the lead in trying to synthetically judge the depositional enviro nment, transporting agent and forming mechanism of the yellow silt from angles of output forms of iron minerals as well as grain size distribution features of the samples chose from three representative sections and a drill core. The DRS first derivative curves show the peak height of iron minerals decreasing from hematite (565 nm)to goethite (505 and 435 nm), which reflects a relatively dry, cold climate that coincides with the aeolian loess widely distributed in the northwest China, but reverses of the fluvial and marine deposits which experienced a well hydration in humid conditions over a long period of time in study area. LPS analysis show that grain size from top to bottom of the sections and drill core are homogeneous and typical of aeolian sediments. The grain size distribution in the yellow silt is characterized by double peaks with main peak of 10～50μm and a secondary peak of <5 μm, similar to that of loess in northwest China but quite different from associated fluvial and marine deposits featured by unidirectional change of allocation mode of the grain size groups. Based on grain size analysis, DRS results, age range of 10～80 ka, and spatial distribution that both of the positive landforms and buried topographies in the coastal area of south China have this kind of sediments, the yellow silt is considered to represent an aeolian deposit formed during the last glacial period, which is called “loess-like deposits” in our study..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2901 (2014)
IM/FM Phase Delay Time Measurement Method of Laser for TDLAS
ZHANG Chao, and MA Wei-guang
The present paper presents an method of using fiber Michelson interferometer to measure the Intensity-frequency (IM/FM) phase delay change of the laser, it could realize the phase delay time measurement, while modulating the laser. Experimental results show that the laser output signal intensity-frequency (IM/FM) phaseThe present paper presents an method of using fiber Michelson interferometer to measure the Intensity-frequency (IM/FM) phase delay change of the laser, it could realize the phase delay time measurement, while modulating the laser. Experimental results show that the laser output signal intensity-frequency (IM/FM) phase delay of the laser has some differences from the theoretical value. The proposed method can be used to compensate for real-time signal strength-frequency (IM/FM) phase delay effect on the gas concentration measurement results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2908 (2014)
Photoelectric Parametric Test System of LED Based on Virtual Instrument
YANG Song-tao, WANG Jing, WANG Li-dong, LIANG Pei, and DONG Qian-min
The standardized measuring principle, requirements and implementations of the above parameters of LEDs were researched and analyzed in the present paper. Then a comprehensive test system involved with optics, machinery and computer was designed to accomplish data acquisition, algorithm design and interface design on viThe standardized measuring principle, requirements and implementations of the above parameters of LEDs were researched and analyzed in the present paper. Then a comprehensive test system involved with optics, machinery and computer was designed to accomplish data acquisition, algorithm design and interface design on virtual instrument using NI data acquisition card USB6210. And convincing results of LEDs’ parameters, including peak wavelength, width of half-peak wavelength, centroid wavelength, chromaticity coordinates, purity, correlated color temperature and the forward voltage/current, were achieved with good consistency based on the measured spectrum. The system owns simple interface, reliable algorithms and stable results. Respective measurements on five kinds of color of LED result in an average error less than 3%, which show an ideal performance of the system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2912 (2014)
Preparation and Photoluminescent Property of Sphere Y2.96Al5O12∶0.04Ce3+ Phosphor for White Light-Emitting Diodes
LI Zhao, ZHAO Xi-cheng, and JIANG Yuan-ru
Cesium ions doped yttrium aluminum garnet (Y2.96Al5O12∶0.04Ce3+) phosphors for white light emitting diodes (WLED) were successfully prepared by hydrothermal-thermolysis method. The phase composition, morphology, and photoluminescent properties of the prepared powders were investigated by X-ray diffraction, scanning eleCesium ions doped yttrium aluminum garnet (Y2.96Al5O12∶0.04Ce3+) phosphors for white light emitting diodes (WLED) were successfully prepared by hydrothermal-thermolysis method. The phase composition, morphology, and photoluminescent properties of the prepared powders were investigated by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and photoluminescence spectroscopy. The results indicated that the successful preparation of the pure Y2.96Al5O12∶0.04Ce3+ powders are spherical particles and have good dispersibility. The phosphors were excited by the blue light with wavelength of 460 nm, and a broad peak at 550 nm was observed in the emission spectrum. Moreover, the emission peak intensity of the YAG∶Ce3+ powders prepared by hydrothermal-thermolysis method was higher than that of the samples prepared by traditional high temperature solid state method. Furthermore, the quantum efficiency of the white LED produced by the phosphors and blue chip was measured by the integrating sphere coupled fluorescence spectrometer, and the results indicated that the absolute quantum efficiency and external quantum efficiency of Y2.96Al5O12∶0.04Ce3+ phosphors prepared by hydrothermal-thermolysis method were 88.40% and 78.64%, respectively, with the color coordinates of (0.453 8, 0.531 8) and the color temperature of 358 4 K. The prepared Y2.96Al5O12∶0.04Ce3+ phosphors exhibited excellent stability and repeatability, and acted as excellent yellow phosphors for warm white LED..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2918 (2014)
Fourier Transform Infrared Spectral Analysis on Peanut (Arachis Hypogaea) Plants under Calcium Deficiency Stress
GAO Li-li, WANG Sheng-feng, HAN Ya, LIU Zi-fei, HUANG Jin-sheng, Hilman, LIU Rong-le, and WANG Hong
The objective of the present study was to reveal different tolerance of peanut plants to Ca deficiency by determining Ca uptake and Fourier transform infrared spectral (FTIR) differences of two peanut cultivars grown in nutrition solution. Peanut cultivars LH11 and YZ9102 were selected. Seedlings at the first leaf stagThe objective of the present study was to reveal different tolerance of peanut plants to Ca deficiency by determining Ca uptake and Fourier transform infrared spectral (FTIR) differences of two peanut cultivars grown in nutrition solution. Peanut cultivars LH11 and YZ9102 were selected. Seedlings at the first leaf stage were cultivated for 28 days in nutrient solution with 0, 0.01 and 2.0 mmol·L-1 Ca treatments, respectively. The results showed that under 0 and 0.01 mmol·L-1 Ca supply, YZ9102 did not show Ca deficiency symptoms and the plant biomass did not change, whereas LH11 exhibited shoot-tip necrosis, smaller plant size, more lateral branches, and plant dry matter weights decreased significantly. YZ9102 had higher plant Ca concentration and Ca accumulation than LH11. Besides, for LH11, Ca was mainly accumulated in roots, while for YZ9102 mainly in leaves. As compared with plants cultivated in 2.0 mol·L-1 Ca nutrition, root, stem and leaf of LH11 plants under Ca deficiency stress showed higher transmittance at peaks 1 060, 1 380, 1 655, 2 922, and 3 420 cm-1 in FTIR spectra, indicating that the contents of protein, sugar and lipid decreased obviously in LH11 plants in condition that Ca supply was limited. However, the FTIR spectra of YZ9102 were less affected by Ca deficiency. It is suggested that YZ9102 might be more tolerant to Ca deficiency..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2923 (2014)
Fast Determination of Induction Period of Motor Gasoline Using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy
LIU Ya-fei, YUAN Hong-fu, SONG Chun-feng, XIE Jin-chun, LI Xiao-yu, and YAN De-lin
A new method is proposed for the fast determination of the induction period of gasoline using Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR). A dedicated analysis system with the function of spectral measurement, data processing, display and storage was designed and integrated using a FoA new method is proposed for the fast determination of the induction period of gasoline using Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR). A dedicated analysis system with the function of spectral measurement, data processing, display and storage was designed and integrated using a Fourier transform infrared spectrometer module and chemometric software. The sample presentation accessory designed which has advantages of constant optical path, convenient sample injection and cleaning is composed of a nine times reflection attenuated total reflectance (ATR) crystal of zinc selenide (ZnSe) coated with a diamond film and a stainless steel lid with sealing device. The influence of spectral scanning number and repeated sample loading times on the spectral signal-to-noise ratio was studied. The optimum spectral scanning number is 15 times and the optimum sample loading number is 4 times. Sixty four different gasoline samples were collected from the Beijing-Tianjin area and the induction period values were determined as reference data by standard method GB/T 8018—87. The infrared spectra of these samples were collected in the operating condition mentioned above using the dedicated fast analysis system. Spectra were pretreated using mean centering and 1st derivative to reduce the influence of spectral noise and baseline shift. A PLS calibration model for the induction period was established by correlating the known induction period values of the samples with their spectra. The correlation coefficient (R2), standard error of calibration (SEC) and standard error of prediction (SEP) of the model are 0.897, 68.3 and 91.9 minutes, respectively. The relative deviation of the model for gasoline induction period prediction is less than 5%, which meets the requirements of repeatability tolerance in GB method. The new method is simple and fast. It takes no more than 3 minutes to detect one sample. Therefore, the method is feasible for implementing fast determination of gasoline induction period, and of a positive meaning in the evaluation of fuel quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2929 (2014)
A Phase Error Correction Method for the New Fourier Transforms Spectrometer
WANG Ning, GONG Tian-cheng, CHEN Jian-jun, LI Yang, YANG Yi-ning, ZHU Yong, ZHANG Jie, and CHEN Wei-min
To decrease the distortion of the recovered spectrum, improve the quantity of the recovered spectrum and decrease the influence of the phase error of the new spectrum detection system based on MEMS (micro-electro-mechanical systems) micro-mirrors, a new phase error correction method for this system is proposed in the pTo decrease the distortion of the recovered spectrum, improve the quantity of the recovered spectrum and decrease the influence of the phase error of the new spectrum detection system based on MEMS (micro-electro-mechanical systems) micro-mirrors, a new phase error correction method for this system is proposed in the present paper. The source of phase error of the spectrum detection system based on MEMS micro-mirrors is analyzed firstly. The analyzed result indicated that the phase error of the new spectral Fourier transform detection system is the zero drift of the optical path difference, and the phase error can be corrected by Zero-crossing sampling which is realized by improving the structure of the interferometer system and Mertz product. The spectrum detection system is set up and the phase error correction method is verified by this system. The experiment result is show that the quantity of the recovered spectrum of the spectrum detection is improved obviously by using the improved interferometer system and Mertz product, and the recovered spectrum has no negative peaks and the side lobes is suppressed markedly. This correction method can reduce the influence caused by phase error to the system performance well and improve the spectral detection performance effectively. In this paper, the origin of the system phase error based on the new MEMS micromirror Fourier transform spectroscopy detection system is analyzed, and the phase error correction method is proposed. This method can improve the performance of the spectrum detection system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2934 (2014)
Reason Analysis of Inadaptability and Its Correction Research on the Authenticity Identification Model of West Lake Longjing Tea Based on LVF Micro-NIR Spectrometer
WANG Dong, PAN Li-gang, WANG Ji-hua, LI An, JIN Xin-xin, ZHU Ye-wei, and MA Zhi-hong
In the present paper, the micro-NIR spectrometer with the splitter of linear variable filter was used to develop the recognition models of the West Lake Longjing tea and the ordinary flat tea of the year 2012 and 2013. The NIR spectral data of different years and different storage times were decomposed by PCA algorithmIn the present paper, the micro-NIR spectrometer with the splitter of linear variable filter was used to develop the recognition models of the West Lake Longjing tea and the ordinary flat tea of the year 2012 and 2013. The NIR spectral data of different years and different storage times were decomposed by PCA algorithm. The PLS-DA models were developed by the representative samples selected by the mathematical characteristics of PCA-scores’ distribution in order to analyze the reason for the inadaptability of the models according to mathematical principles and find out the solution for its correction. Being examined by the external validation set, the adaptability of the authenticity identification model was enhanced effectively. The result of this research indicated that, for the West Lake Longjing tea and the ordinary flat tea, the correct recognition rate of the model developed by all different-year samples’ NIR spectral data would be enhanced effectively. The model developed by the NIR spectral data of different storage time samples indicated that the physicochemical properties of the ordinary flat tea have changed remarkably after cryopreservation for 3 months, while the physicochemical properties of the West Lake Longjing tea are relatively stable. The model adaptabilities for different years and different storage times were studied according to the mathematical perspective of the principal component characteristics of spectral data. After the authenticity identification model of West Lake Longjing tea was developed, the prediction accuracy was enhanced effectively. This research would provide reference for not only the application of NIR spectroscopy in quality grading and safety of agricultural products, but also the enhancement of the prediction accuracy of the NIR grading models for agricultural products..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2938 (2014)
Changes in Chemistry Component Structure and Microstructure Characterization of Acetylated Wood Before and After UV Radiation
FU Zhan, LIU Yi, XING Fang-ru, and GUO Hong-wu
The poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks’ intensity which belonged to the chemistry components of sampThe poplar powder was acetylated with different duration as sample, processed ray radiation by using ultraviolet test box, contrasting the influences to lightfastness of wood with different acetylation degree, analyzing changing rules of characteristic peaks’ intensity which belonged to the chemistry components of samples based on FTIR spectra, and the relationship between duration of acetylation and changes of chemistry components was established, The results showed that: Before UV radiation, the characteristic peaks’ intensity of acetylated poplar powder at 1 739 cm-1 which belonged to CO in saturated esters compounds and 1 385 cm-1 which belonged to C—H in acetate were higher than untreated ones’, the poplar powder with 40 min’s acetylation has the highest characteristic peaks’ intensity, highest weight gain rate, remarkable acetylation effect; After UV radiation, characteristic peaks’ intensity of Benzene at 1 504 cm-1 which belonged to lignin of poplar powder was obviously higher than untreated ones’, and characteristic peaks’ intensity of poplar powder with 40 min’s acetylation was the highest, this showed that acetylation could effectively reduce the light degradation of wood chemistry components, in order to improve the lightfastness, especially the poplar powder with 40 min’s acetylation; SEM photos showed that, the fibrous surface of acetylated poplar powder was more smooth and had more narrow particle size than untreated ones’, so acetylation can effectively improve the stability of wood..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2944 (2014)
Research on Wavelength Variates Selection Methods for Determination of Oil Yield in Oil Shales using Near-Infrared Spectroscopy
ZHAO Zhen-ying, LIN Jun, ZHANG Fu-dong, and LI Jun
The wavelength selection is an important step in the spectra modeling analysis. In the present paper, three wavelength selection methods, including correlation coefficient (CC), moving window partial least squares (MWPLS) and uninformative variables elimination (UVE), were studied for the determination of oil yield in The wavelength selection is an important step in the spectra modeling analysis. In the present paper, three wavelength selection methods, including correlation coefficient (CC), moving window partial least squares (MWPLS) and uninformative variables elimination (UVE), were studied for the determination of oil yield in oil shale using near-infrared (NIR) diffuse reflection spectroscopy. The above methods were used to eliminate the redundant and irrelevant variables in spectral data for enhancing the analytic efficiency and predictive ability of calibration model. The effects of thresholds of CC, window width of MWPLS and noise matrix of UVE were studied. Partial least squares regression was used to build prediction model for predicting oil yield in oil shale, and the performance of PLS models constructed with and without the using of wavelength selection methods were compared. The results show that any of the three methods can simplify the calibration model and improve the performance of model. By using UVE, the total number of wavelength variables of spectral data, the RMSECV of calibration model and the RMSEP of prediction model were decreased by 22.8%, 9.3% and 4.5%, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2948 (2014)
Thermal Infrared Emissivity Spectrum and Its Characteristics of Crude Oil Slick Covered Seawater
XIONG Pan, GU Xing-fa, YU Tao, MENG Qing-yan, LI Jia-guo, SHI Ji-xiang, CHENG Yang, WANG Liang, LIU Wen-song, LIU Qi-yue, and ZHAO Li-min
Detecting oil slick covered seawater surface using the thermal infrared remote sensing technology exists the advantages such as: oil spill detection with thermal infrared spectrum can be performed in the nighttime which is superior to visible spectrum, the thermal infrared spectrum is superior to detect the radiation cDetecting oil slick covered seawater surface using the thermal infrared remote sensing technology exists the advantages such as: oil spill detection with thermal infrared spectrum can be performed in the nighttime which is superior to visible spectrum, the thermal infrared spectrum is superior to detect the radiation characteristics of both the oil slick and the seawater compared to the mid-wavelength infrared spectrum and which have great potential to detect the oil slick thickness. And the emissivity is the ratio of the radiation of an object at a given temperature in normal range of the temperature (260~320 K) and the blackbody radiation under the same temperature., the emissivity of an object is unrelated to the temperature, but only is dependent with the wavelength and material properties. Using the seawater taken from Bohai Bay and crude oil taken from Gudao oil production plant of Shengli Oilfield in Dongying city of Shandong Province, an experiment was designed to study the characteristics and mechanism of thermal infrared emissivity spectrum of artificial crude oil slick covered seawater surface with its thickness. During the experiment, crude oil was continuously dropped into the seawater to generate artificial oil slick with different thicknesses. By adding each drop of crude oil, we measured thereflectivity of the oil slick in the thermal infrared spectrum with the Fourier transform infrared spectrometer (102F) and then calculated its thermal infrared emissivity. The results show that the thermal infrared emissivity of oil slick changes significantly with its thickness when oil slick is relatively thin (20~120 μm), which provides an effective means for detecting the existence of offshore thin oil slick. In the spectrum ranges from 8 to 10 μm and from 13.2 to 14 μm, there is a steady emissivity difference between the seawater and thin oil slickwith thickness of 20 μm. The emissivity of oil slick changes marginally with oil slick thickness and clearly below that of seawater in the spectrum range from 11.7 to 14 μm, this spectrum range can be practically used to distinguish oil slick from seawater; Around the wavelength of 11.72, 12.2, 12.55, 13.48 and 13.8 μm, the emissivity of oil slick presents clearly increasing or decreasing trends with the increase of its thickness, which are one of the best wavelengths for observing the offshore oil slick and estimating its thickness..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2953 (2014)
FTIR Study of Hydrogen Bonds in Coal under Drop Weight Impact Testing
LI Cheng-wu, WANG Jin-gui, XIE Bei-jing, DONG Li-hui, SUN Ying-feng, and CAO Xu
There are many hydrogen bonds in coal, which affect the chemical structure and properties of coal. FTIR has been applied to the characterization study of the hydrogen bonds of Dongpang coals, which were under drop weight impact. There exists five kinds of hydrogen bonds in the coal: free OH groups, OH…π, OH…OH, cyclic There are many hydrogen bonds in coal, which affect the chemical structure and properties of coal. FTIR has been applied to the characterization study of the hydrogen bonds of Dongpang coals, which were under drop weight impact. There exists five kinds of hydrogen bonds in the coal: free OH groups, OH…π, OH…OH, cyclic OH tetramers and OH…N. Absorption strength of intermolecular hydrogen bonds markedly declined after impact. Free OH groups mechanical-power chemical reacted in drop weight impact testing. The infrared spectrum were curve-resolved into their component bands. The absorption strength of various hydrogen bonds decreased with the increase of impact energy, but the trend was slowing. By statistical relationship between then, we find then complying with power function relationship. By comparing the exponents of fitted equations, we concluded that failure sensitivity sequence of hydrogen bonds to the impact: free OH groups>cyclic OH tetramers>OH…N>OH…π>OH…OH..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2961 (2014)
Identification of Dendrobium Varieties by Infrared Spectroscopy
LIU Fei, WANG Yuan-zhong, YANG Chun-yan, and JIN Hang
The difference of Dendrobium varieties were analyzed by Fourier transform infrared (FTIR) spectroscopy. The infrared spectra of 206 stems from 30 Dendrobium varieties were obtained, and showed that polysaccharides, especially fiber, were the main components in Dendrobium plants. FTIR combined with Wilks’ Lambda stepwisThe difference of Dendrobium varieties were analyzed by Fourier transform infrared (FTIR) spectroscopy. The infrared spectra of 206 stems from 30 Dendrobium varieties were obtained, and showed that polysaccharides, especially fiber, were the main components in Dendrobium plants. FTIR combined with Wilks’ Lambda stepwise discriminative analysis was used to identify Dendrobium varieties. The effects of spectral range and number of training samples on the discrimination results were also analysed. Two hundred eighty seven variables in the spectral range of 1 800～1 250 cm-1 were studied, and showed that the return discrimination is 100% correct when the training samples number of each species was 2, 3, 4, 5, and 6, respectively, whereas for the remaining samples the correct rates of identification were equal to 79.4%, 91.3%, 93.0%, 98.2%, and 100%, respectively. The same discriminative analyses on five different training samples in the spectral range of 1 800～1 500, 1 500～1 250, 1 250～600, 1 250～950 and 950～650 cm-1 were compared, which showed that the variables in the range of 1 800～1 250, 1 800～1 500 and 950～600 cm-1 were more suitable for variety identification, and one can obtain the satisfactory result for discriminative analysis when the training sample is more than 3. Our results indicate that FTIR combined with stepwise discriminative analysis is an effective way to distinguish different Dendrobium varieties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2968 (2014)
Study on the Tibetan Medicine Swertia mussotii Franch and Its Extracts by Fourier Transform Infrared Spectroscopy
YANG Hong-xia, MA Fang, DU Yu-zhi, SUN Su-qin, and WEI Li-xin
The objective of the present study is to research the herb of Swertia mussotii Franch and its different extracts by tri-step infrared spectroscopy. The main constitute of Swertia mussotii Franch-gentiamarin, which is also the higher content constitute, was selected as the control components to analyze the infrared specThe objective of the present study is to research the herb of Swertia mussotii Franch and its different extracts by tri-step infrared spectroscopy. The main constitute of Swertia mussotii Franch-gentiamarin, which is also the higher content constitute, was selected as the control components to analyze the infrared spectroscopy and second derivative infrared spectroscopy of different extracts of Swertia mussotii Franch, at the same time, the different concentration of ethanol extracts were also analyzed by two-dimensional correlation spectroscopy(2D-COS). The results indicated that the intensity of 1 611 and 1 075 cm-1 of gentiamarin, which are its two main absorptions in the infrared spectra, has the positive correlation with the content change in different extracts. The infrared spectroscopy of extracts are similar if the polarity of extract solvents is close; with the decreases in solution polarity, the intensity of 2 853, 1 733, 1 464, 1 277 and 1 161 cm-1 in infrared spectroscopy of different extracts is increased, the content of esters and the extraction percentage terpenoid compounds are also increased; the different concentration of ethanol extracts has obviously difference when they are analyzed by two – dimensional correlation spectroscopy(2D-COS). The positive correlation between the intensity of absorptions and the content of the gentiamarin indicates that the infrared spectroscopy can reflect the content change in constitute; the similar and the change trend of the different concentrations of ethanol extract infrared spectroscopy approve the scientificalness of decoction of traditional medicine; infrared spectroscopy that used in the research can be used as an accurate, rapid and effective method in the pharmacological activity tests of transitional herbal Swertia mussotii F. and it’s different extracts, even in the research on the tibetan medicine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2973 (2014)
Measurements of the Concentration of Atmospheric CO2 Based on OP/FTIR Method and Infrared Reflecting Scanning Fourier Transform Spectrometry
WEI Ru-yi, ZHOU Jin-song, ZHANG Xue-min, YU Tao, GAO Xiao-hui, and REN Xiao-qiang
The present paper describes the observations and measurements of the infrared absorption spectra of CO2 on the Earth’s surface with OP/FTIR method by employing a mid-infrared reflecting scanning Fourier transform spectrometry, which are the first results produced by the first prototype in China developed by the team ofThe present paper describes the observations and measurements of the infrared absorption spectra of CO2 on the Earth’s surface with OP/FTIR method by employing a mid-infrared reflecting scanning Fourier transform spectrometry, which are the first results produced by the first prototype in China developed by the team of authors. This reflecting scanning Fourier transform spectrometry works in the spectral range 2 100～3 150 cm-1 with a spectral resolution of 2 cm-1. Method to measure the atmospheric molecules was described and mathematical proof and quantitative algorithms to retrieve molecular concentration were established. The related models were performed both by a direct method based on the Beer-Lambert Law and by a simulating-fitting method based on HITRAN database and the instrument functions. Concentrations of CO2 were retrieved by the two models. The results of observation and modeling analyses indicate that the concentrations have a distribution of 300~370 ppm, and show tendency that going with the variation of the environment they first decrease slowly and then increase rapidly during the observation period, and reached low points in the afternoon and during the sunset. The concentrations with measuring times retrieved by the direct method and by the simulating-fitting method agree with each other very well, with the correlation of all the data is up to 99.79%, and the relative error is no more than 2.00%. The precision for retrieving is relatively high. The results of this paper demonstrate that, in the field of detecting atmospheric compositions, OP/FTIR method performed by the Infrared reflecting scanning Fourier transform spectrometry is a feasible and effective technical approach, and either the direct method or the simulating-fitting method is capable of retrieving concentrations with high precision..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2978 (2014)
Feasibility Study on an Approach for Identifying Corn Kernel Varieties with Seed Coating Agents via Near Infrared Spectroscopy
JIA Shi-qiang, GUO Ting-ting, LIU Zhe, YAN Yan-lu, AN Dong, GU Jian-cheng, LI Shao-ming, ZHANG Xiao-dong, and ZHU De-hai
It is generally accepted that near infrared reflectance spectroscopy (NIRS) can be used to identify variety authenticity of bare maize seeds. In practical, maize seeds are covered with seed coating agents. Therefore it’s of huge significance to investigate the feasibility of identifying coated maize seeds by NIRS. ThisIt is generally accepted that near infrared reflectance spectroscopy (NIRS) can be used to identify variety authenticity of bare maize seeds. In practical, maize seeds are covered with seed coating agents. Therefore it’s of huge significance to investigate the feasibility of identifying coated maize seeds by NIRS. This study employed NIRS to quickly determine the variety of coated maize seeds. Influence of seed coating agent on NIR spectra was discussed. The NIR spectra of coated maize seeds were obtained using an innovative method to avoid the impact of the seed coating agent. Coated seeds were cut open, and the sections were scanned by the spectrometer, so as to acquire the information of the seed itself. Then, support vector machine (SVM), soft independent modeling of class analogy (SIMCA), and biomimetic pattern recognition (BPR) was employed to establish the identification model for four maize varieties, and yield 93%, 95.8%, 98% average correct rate respectively. BPR model showed better performance than SVM and SIMCA models. The robustness of identification model was tested by seeds harvested from four regions and model showed good performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2984 (2014)
IR and Raman Spectra Studies of Rotundine Based on DFT
LI Jun-ping, ZHOU Guang-ming, ZHANG Li-jun, CHENG Hong-mei, and QIN Hong-ying
Infrared spectroscopy (IR), the normal Raman spectroscopy (NRS) and the surface enhanced Raman spectroscopy (SERS) in new Ag/Cu nanomaterial of Rotundine were studied in the present paper. The IR and the NRS of Rotundine were calculated by the density functional theory (DFT) using B3LYP/6-311+G(d,p), then the spectral Infrared spectroscopy (IR), the normal Raman spectroscopy (NRS) and the surface enhanced Raman spectroscopy (SERS) in new Ag/Cu nanomaterial of Rotundine were studied in the present paper. The IR and the NRS of Rotundine were calculated by the density functional theory (DFT) using B3LYP/6-311+G(d,p), then the spectral intensity graph of Rotundine were given. The vibrational peaks were assigned comprehensively by the visualization software of Gauss view 5.0. Rotundine has obvious infrared and Raman vibrational peak in the wave number range of 3 300～2500 and 1 800～600 cm-1. SnCl2 and PVP was used as capping agent for the silver nanoparticles in SERS of Rotundine. Finally, by using the method of cyclic immersion well dispersed silver nanoparticles was obtained and achieved good enhancement effect. This molecule acquired strong selective enhancement vibration peak, In the wave number ranges of 1 500～1 400 and 1 000～700 cm-1 the enhancement effect is most obvious. After analyzed, the methylene of this molecule is adsorbed on the silver nanoparticles surface and the angle between the benzene ring and the silver substrate is close to 90°. The theoretically calculated spectra of Rotundine are consistent with the obtained experimental spectra. There are some differences may be due to the interaction forces between molecules and so on. The visualization software displayed the structure characteristics and molecular group vibration of this molecular visually and provided important basis for assigning the vibrational peaks. Rotundine is an important traditional Chinese medicine agent contained in many kinds of sedative drugs. The study provides a strong basis for the rapid, feature and trace identification of Rotundine and also supplies important reference for the biological role of central inhibition of analgesic drugs..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2989 (2014)
Infrared, Raman and Density Functional Study of Vibration Spectra of 2,3-Dichloropyrazine
CHEN Heng-jie, GUO Lei, FANG Wang, and JIA Guo-zhu
Fourier transform infrared (FTIR) spectra of 2,3-dichloropyrazine in the region 400～4000 cm-1 were measured under solid state condition using KBr pellets method and liquid state by the melting method, besides, a Fourier transform Raman (FT-Raman) spectra in region 600～4 000 cm-1 was recorded. Then equilibrium geometry Fourier transform infrared (FTIR) spectra of 2,3-dichloropyrazine in the region 400～4000 cm-1 were measured under solid state condition using KBr pellets method and liquid state by the melting method, besides, a Fourier transform Raman (FT-Raman) spectra in region 600～4 000 cm-1 was recorded. Then equilibrium geometry of 2,3-DCP was optimized, and based on this, the harmonic vibrational frequencies, infrared intensities and Raman activities were calculated using B3LYP method of the density function theory (DFT) in conjunction with 6-311++G(2df,2pd) basis set, furthermore, a comprehensive anharmonic calculation was also been performed for obtaining more accurate vibrational frequencies using second-order perturbation theory treatment based on quadratic, cubic and quartic force constants. Infrared and Raman spectra were simulated corresponding to theory. Experimental FTIR and FT-Raman bands were compared with those positions of peaks obtained from anharmonic calculations and intensities or activities from harmonic carefully. Each vibrational band was assigned and interpreted in detail with help of potential energy distribution (PED) for the first time. In addition, it was shown that anharmonic results exactly reproduced to experimental data, improved the validity of prediction greatly in vibration frequencies, discrepancies between anharmonic and experimental results were limited to below 10 cm-1 in most of vibrational bands, even if in the high energy regions, which have a poor performance for hanmonic calculation, and these differences would be decreased to lower than 19 cm-1. It is extremely helpful for assigning and predicting vibrational spectra. Present conclusion can be expanded to others molecular systems..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2994 (2014)
Identification of the Characteristic Vibrations for 16 PAHs Based on Raman Spectrum
ZENG Ya-ling, JIANG Long, CAI Xiao-yu, and LI Yu
In the present paper, by means of density functional theory in B3LYP/6-311++G(d, p) method, 16 kinds of pollutants, i.e. polycyclic aromatic hydrocarbons (PAHs): naphthalene (Nap), acenaphthylene (AcPy), acenaphthene (Acp), fluorene (Flu), phenanthrene (PA), anthracene (Ant), fluoranthene (Fl), pyrene (Pyr), benzo ［a］ In the present paper, by means of density functional theory in B3LYP/6-311++G(d, p) method, 16 kinds of pollutants, i.e. polycyclic aromatic hydrocarbons (PAHs): naphthalene (Nap), acenaphthylene (AcPy), acenaphthene (Acp), fluorene (Flu), phenanthrene (PA), anthracene (Ant), fluoranthene (Fl), pyrene (Pyr), benzo ［a］ anthracene (BaA), fused two naphthalene (CHR), benzo ［b］ fluoranthene (BbF), benzo ［k］ fluoranthene (BkF), benzo ［a］ pyrene (BaP), dibenzo (a, h) anthracene (DahA), dibenzo ［g, h, i］ pyrene (BghiP) and indene benzene (1, 2, 3-cd) pyrene (IcdP) among the U.S. EPA priority pollutants were selected, whose structures were optimized and Raman vibrational frequencies and depolarization were calculated. The structure, Raman vibrational frequencies and depolarization were basis of identification of PAHs. Studies have shown that Raman vibrations of 16 PAHs are mainly distributed in three frequency regions: 200～1 000 cm-1 (fingerprint region), 1 000～1 700 cm-1 and 3 000～3 200 cm-1 (group frequency region), corresponding vibrations were assigned to ring deformation (ring def), C—C stretching (CCStr), C—H wiggle (CHw) and of these two patterns (CCStrCCw), and C—H stretching (CHStr). Further analysis showed that in fingerprint region the depolarization of 16 PAHs was reduced with the symmetry of benzene deformation vibration enhanced. At the point of minimum depolarization, symmetry and Raman peak of benzene ring breathing vibration were found strongest. At the minimum differential wave number the strongest peak in fingerprint region was distinguishable by micro-Raman spectroscopy. Therefore, 16 PAHs can be individually identified by depolarization and the strongest peak in fringerprint region. Vibration frequencies and peak intensity distribution of alkanes (Akn), olefin (Oe), alkyne (Aye), alcohols and phenols (Aap), aliphatic ether (Ape), arylalkyl ether (Aae), aldehydes (Ahd), ketones (Ktn ), carboxylic acid (Cba), esters (Etr), amines (Aie), nitriles (Nte), amides (Aid), acid anhydride (Ahr), aromatic hydrocarbons (Ahc) were not completely consistent with each other, and interference can be discharged by the differences of frequency and peak intensity distribution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 2999 (2014)
Study on the Order Degree and Geochemical Characteristics of Major Elements of Siliceous Rock in Eastern Qinling Area, China
LV Ming-da, LI Hong-zhong, ZHAO Ming-zhen, MA Zhan-wu, YANG Zhi-jun, and LIANG Jin
Siliceous rocks were extensively distributed in the marine volcanic sedimentary formation of Erlangping Group in the Early Paleozoic in eastern Qinling area. These siliceous rocks formed in the same age, but had differences in the degree of crystallization and order because of the late diagenetic evolution. In the presSiliceous rocks were extensively distributed in the marine volcanic sedimentary formation of Erlangping Group in the Early Paleozoic in eastern Qinling area. These siliceous rocks formed in the same age, but had differences in the degree of crystallization and order because of the late diagenetic evolution. In the present study, the major elements and order degree of the siliceous rocks were studied, which were from the Erlangping Group in Xixia area, Songxian area and Nanzhao area of eartern Qinling orogenic belt. As shown in the results, the siliceous rocks contained SiO2 with percentage between 84.75% and 94.12% and average of 89.09%. The SiO2/(K2O+Na2O) values were from 26.69 to 114.78 with 65.67 as its average, and the values of SiO2/Al2O3 were from 10.48 to 61.52 with average of 30.58. These above characteristics excellently agreed with the geochemical characteristics of hydrothermal siliceous rocks, which deposited in the continental margin environment. In the Raman analytical results, the quartz contributed to the characteristic Raman shifts at 394, 464, 465 and 467 cm-1. In the results of Gaussian fitting the degrees of order increased with the order of siliceous rocks of Songxian area, Nanzhao area and Xixia area, which were witnessed by the descending in FWHM values of quartz in the siliceous rocks of Songxian area, Nanzhao area and Xixia area orderly. Disagreeing with the FWHM values of Gaussian fitting, the silica contents of the siliceous rocks had a rising trend of Songxian (87.36%), Nanzhao (89.57%), Xixia area (90.35%), which meant a descending in impurity elements with the order of Songxian area, Nanzhao area and Xixia areas. According to this, there was high agreement between lower crystallinity degree and higher purity of silica, and this denoted that the rising in order degree of silica would result in lower impurity in siliceous rocks. Although the crystallinity degrees could change with the influences of temperature, pressure and its natural property, the impurity elements decreased with the rising in crystallinity degrees of silica. Although there was excluding of impurity elements during the increase in degrees of crystallinity and order, the key factor for the diversities of major elements in siliceous rocks was not likely to be the excluding of impurity elements during the increase in the crystallinity degrees in silica. In this study, the Raman analysis exhibited to be an effective way to understand the degree of order for the silica of the siliceous rocks, which would be a potential way to study the subsequent diagenetic evolution of siliceous rocks..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3005 (2014)
Synthesis and Characterization of CO2-3 Doping Nano-Hydroxyapatite
LIAO Jian-guo, LI Yan-qun, DUAN Xing-ze, and LIU Qiong
CO2-3 doping is an effective method to increase the biological activity of nano-hydroxyapatite (n-HA). In the present study, calcium nitrate and trisodium phosphate were chosen as raw materials, with a certain amount of Na2CO3 as a source of CO2-3 ions, to synthesize nano-carbonate hydroxyapatite (n-CHA) slurry by soluCO2-3 doping is an effective method to increase the biological activity of nano-hydroxyapatite (n-HA). In the present study, calcium nitrate and trisodium phosphate were chosen as raw materials, with a certain amount of Na2CO3 as a source of CO2-3 ions, to synthesize nano-carbonate hydroxyapatite (n-CHA) slurry by solution precipitation method. The structure and micro-morphology of n-CHA were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and Raman spectroscopy (RS). The results revealed that the synthetic n-HA crystals are acicular in nanometer scale and have a crystal size of 20～30 nm in diameter and 60～80 nm in length, which are similar to natural bone apatite. And the crystallinity of n-CHA crystals decreases to the increment of CO2-3. Samples with more CO23 have composition and structure more similar to the bone apatite. The value of lattice parameters a decreases, value of c increases, and c/a value increases with the increase in the amount of CO2-3, in accordance with crystal cell parameters change rule of type B replacement. In the AB mixed type (substitution OH- and PO3-4) CHA, IR characteristic peak of CO2-3 out-of-plane bending vibration appears at 872 cm-1, meanwhile, the asymmetry flexible vibration band is split into band at 1 454 cm-1 and band at 1 420 cm-1, while weak CO23-peak appears at 1 540 cm-1. CO2-3 Raman peak of symmetric stretching vibration appears at 1 122 cm-1. CO2-3 B-type (substitution PO3-4) peak appeared at 1 071 cm-1. Through the calculation of integral area ratio of PO3-4/CO2-3, OH-/CO2-3, and PO3-4/OH-, low quantity CO2-3 is B-type and high quantity CO2-3 is A-type (substitution OH-). The results show that the synthesized apatite crystals are AB hybrid substitued nano-carbonate hydroxyapatite, however B-type replacement is the main substitute mode. Due to similarity in the shape, size, crystal structure and growth mode, the synthesized apatite crystals can be called a kind of bone-like apatite..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3011 (2014)
Research on Rapid Determination of Organic Matter Concentration in Aquaculture Water Based on Ultraviolet/Visible Spectroscopy
CAO Hong, QU Wen-tai, YANG Xiang-long, JIA Sheng-yao, WANG Chun-long, and LU Chen
Ultraviolet/visible (UV/Vis) spectroscopy was investigated for the rapid determination of chemical oxygen demand (COD) which was an indicator to measure the concentration of organic matter in aquaculture water. A total number of 135 collected turtle breeding water samples were scanned for UV/Vis spectrum, uninformativeUltraviolet/visible (UV/Vis) spectroscopy was investigated for the rapid determination of chemical oxygen demand (COD) which was an indicator to measure the concentration of organic matter in aquaculture water. A total number of 135 collected turtle breeding water samples were scanned for UV/Vis spectrum, uninformative variable elimination (UVE) and successive projections algorithm (SPA) were combined as a mixed variable selection method to perform characteristic wavelength selection from the full wavelength spectrum, 7 characteristic wavelengths were selected from full 201 UV/Vis spectral variables, which were just 3.48% number of the full range spectrum, and the calibration time and complexity of the modeling were greatly reduced. The predicted results which were obtained by using least squares-support vector machine (LS-SVM) calibration showed that the characteristic wavelengths achieved better results (0.89 for correlation coefficient (r), 15.46 mg·L-1 for root mean square error of prediction (RMSEP)) than full wavelengths did (0.88 for r and 15.71 mg·L-1 for RMSEP). The comprehensive results revealed that the UV/Vis characteristic wavelengths which were obtained by UVE-SPA variable selection method, combined with LS-SVM calibration could apply to the rapid and accurate determination of COD in aquaculture water. Moreover, this study laid the foundation for further implementation of online analysis of aquaculture water and rapid determination of other water quality parameters..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3015 (2014)
Experimental Research of Turbidity Influence on Water Quality Monitoring of COD in UV-Visible Spectroscopy
TANG Bin, WEI Biao, WU De-cao, MI De-ling, ZHAO Jing-xiao, FENG Peng, JIANG Shang-hai, and MAO Ben-jiang
Eliminating turbidity is a direct effect spectroscopy detection of COD key technical problems. This stems from the UV-visible spectroscopy detected key quality parameters depend on an accurate and effective analysis of water quality parameters analytical model, and turbidity is an important parameter that affects the mEliminating turbidity is a direct effect spectroscopy detection of COD key technical problems. This stems from the UV-visible spectroscopy detected key quality parameters depend on an accurate and effective analysis of water quality parameters analytical model, and turbidity is an important parameter that affects the modeling. In this paper, we selected formazine turbidity solution and standard solution of potassium hydrogen phthalate to study the turbidity affect of UV - visible absorption spectroscopy detection of COD, at the characteristics wavelength of 245, 300, 360 and 560 nm wavelength point several characteristics with the turbidity change in absorbance method of least squares curve fitting, thus analyzes the variation of absorbance with turbidity. The results show, In the ultraviolet range of 240 to 380 nm, as the turbidity caused by particle produces compounds to the organics, it is relatively complicated to test the turbidity affections on the water Ultraviolet spectra; in the visible region of 380 to 780 nm, the turbidity of the spectrum weakens with wavelength increases. Based on this, this paper we study the multiplicative scatter correction method affected by the turbidity of the water sample spectra calibration test, this method can correct water samples spectral affected by turbidity. After treatment, by comparing the spectra before, the results showed that the turbidity caused by wavelength baseline shift points have been effectively corrected, and features in the ultraviolet region has not diminished. Then we make multiplicative scatter correction for the three selected UV liquid-visible absorption spectroscopy, experimental results shows that on the premise of saving the characteristic of the Ultraviolet-Visible absorption spectrum of water samples, which not only improve the quality of COD spectroscopy detection SNR, but also for providing an efficient data conditioning regimen for establishing an accurate of the chemical measurement methods..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3020 (2014)
Ultraviolet-Visible Spectrometry Analysis of Insoluble Xanthate Heavy Metal Complexes
QIU Bo, LIU Jin-feng, LIU Yao-chi, YANG Zhao-guang, and LI Hai-pu
A ultraviolet-visible spectrometry method of determining insoluble xanthate heavy metal complexes in flotation wastewater was the first time to be put forward. In this work, the changes of ultraviolet-visible spectra of xanthate solution after the addition of various heavy metal ions were investigated firstly. It was fA ultraviolet-visible spectrometry method of determining insoluble xanthate heavy metal complexes in flotation wastewater was the first time to be put forward. In this work, the changes of ultraviolet-visible spectra of xanthate solution after the addition of various heavy metal ions were investigated firstly. It was found that Pb2+ and Cu2+ can form insoluble complexes with xanthate, while Fe2+, Zn2+ and Mn2+ have little effect on the ultraviolet absorption of xanthate solution. Then the removal efficiencies of filter membrane with different pore sizes were compared, and the 0.22 μm membrane was found to be effective to separate copper xanthate or lead xanthate from the filtrate. Furthermore, the results of the study on the reaction of sodium sulfide and insoluble xanthate heavy metal complexes showed that S2- can release the xanthate ion quantitatively from insoluble complexes to solution. Based on the above research, it was concluded that the amount of insoluble xanthate heavy metal complexes in water samples can be obtained through the increase of free xanthate in the filtrate after the addition of sodium sulfide. Finally, the feasibility of this method was verified by the application to the analysis of flotation wastewater from three ore-dressing plants in the Thirty-six Coves in Chenzhou..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3025 (2014)
Determination of Clopidogrel Sulfate in Pharmaceutical Formulation and Biological Fluids by Extraction Spectrofluorimetric Method
LIAN Wei-qin, GONG Ai-qin, WANG Lu, and ZHU Xia-shi
A simple and sensitive spectrofluorimetric method has been developed for the determination of clopidogrel sulfate in pharmaceutical formulation and human urine/ serum. It is based on the formation of ion-pair complex between clopidogrel sulfate and alizarin red in 0.3 mol·L-1 hydrochloric acid solution. The ion paA simple and sensitive spectrofluorimetric method has been developed for the determination of clopidogrel sulfate in pharmaceutical formulation and human urine/ serum. It is based on the formation of ion-pair complex between clopidogrel sulfate and alizarin red in 0.3 mol·L-1 hydrochloric acid solution. The ion pair complex was extracted in dichloromethane and the fluorescence intensity was measured at 550 nm after excitation at 428 nm. The various factors influencing ion-pair complex formation and fluorescence determination were discussed. Under the optimized conditions, the fluorescence value showed a good linear relationship with the clopidogrel sulfate concentration ranging from 1.0 to 11.0 μg·mL-1. The equation of calibration curve was F=53.32+35.01c(μg·mL-1), r=0.994, and the detection limit was found to be 0.11 μg·mL-1. No interference was observed from common co-existing substances or pharmaceutical excipient. The determination recoveries of clopidogrel sulfate in pharmaceutical formulation and human urine/serum samples were 90.6%～99.3%, 104.6%～109.3%, 96.3%～105.0%, respectively. The method was successfully applied to detect clopidogrel sulfate in clopidogrel sulfate tablet and human urine/ serum. The obtained results of clopidogrel sulfate tablet were in good agreement with the results of HPLC. Therefore, it is concluded that the proposed method is simple, sensitive and rapid for the determination of clopidogrel sulfate in real samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3030 (2014)
Synthesis and Spectroscopic Properties of Some Novel BODIPY Dyes
ZHA Jia-yu, LIN Ying-hui, XU Jun-chao, ZHANG You-lai, and ZENG Lin-tao
BODIPY dyes have some unique properties including high fluorescence quantum yield, large extinction coefficiency, narrow absorption and emission band. However, most of BODIPY dyes display short emission wavelength and small Stokes shift, which limits their applications in biosensing and bioimaging in vivo. For bioimagiBODIPY dyes have some unique properties including high fluorescence quantum yield, large extinction coefficiency, narrow absorption and emission band. However, most of BODIPY dyes display short emission wavelength and small Stokes shift, which limits their applications in biosensing and bioimaging in vivo. For bioimaging application, a fluorescent dye with long emission wavelength and large Stokes shift is highly desired. To push the absorption and emission spectrum of BODIPY to red and even far-red region, a COOEt group was introduced to the meso position, and some aromatic group was attached to the 3,5 position of BODIPY core. The structure of resulting compounds were comfirmed by 1H NMR, 13C NMR and HR-MS. Dye-1 displays a strong UV-Vis absorption band centered at 536 nm and a sharp emission band is located at 592 nm, which is significantly red-shifted (80 nm) compared to ordinary BODIPY analogs. In addition, the meso-COOEt substituted BODIPYs exhibit high quantum yield and red to far-red emission. Notably surprisingly, the meso-COOEt substituted BODIPYs display almost separated UV-Vis absorption and emission spectra with a large Stokes shift (~60 nm). Time-dependent density functional theory calculations were conducted to understand the structure-optical properties relationship, and it was revealed that the large Stokes shift was resulted from the geometric change from the ground state to the first excited singlet state. The spectroscopic properties of these BODIPY dyes display very subtle solvent-dependence effect. Furthermore, BODIPY was tested for its ability of imaging in living cells. The results indicate that Dye-1 is a water-soluble and membrane-permeable probe. Therefore, these BODIPYs are a new family dyes with excellent spectroscopic properties and can be good candidates for bioimaging in living cells..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3034 (2014)
A New Multivariate Quantitative Method of Spectral Analysis for Multicomponent System
HU Ai-qin, YUAN Hong-fu, YAO Zhi-xiang, LIU Ya-fei, SONG Chun-feng, and LI Xiao-yu
In the spectral analysis, a large-scale application of the traditional multivariate analysis methods has been limited by both high cost and poor applicability of the calibration models. A new multivariate analysis method was proposed for multicomponent systems in the present paper. Determining MTBE content in gasoline In the spectral analysis, a large-scale application of the traditional multivariate analysis methods has been limited by both high cost and poor applicability of the calibration models. A new multivariate analysis method was proposed for multicomponent systems in the present paper. Determining MTBE content in gasoline solution by infrared spectroscopy was studied. The spectra of five kinds of gasoline and their 50 narrow distillation fractions were used to build the background library. The oblique projection algorithm was applied to the spectra of MTBE gasoline solution samples to extract the pure spectral signal of MTBE in the solution. A unary linear regression curve was built between the pure spectral signals of MTBE and their concentrations with a correlation coefficient of 0.995 2 and an intercept of 0.025. Compared with the orthogonal projection algorithm method and PLS model method, a large amounts of calibration samples and complex model are no longer needed by the new method which is simpler, more accurate and with better applicability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3040 (2014)
Investigation on the Cyanine Dyes Supramolecular Assembly and Chiral Inducement by Fulvic Acid
ZHANG Xiu-feng, CHEN Lei, YANG Qian-fan, SUN Xiao-ran, CHEN Hong-bo, YANG Guang, and TANG Ya-lin
Using cyanine dyes supramolecular as molecular probes to mark FA has important significance in life sciences and pharmaceutical chemistry, which can detect FA as drug efficacy mechanism and the change in physiological activity. In the present paper, we investigated supramolecular assembly and chiral inducement of cyaniUsing cyanine dyes supramolecular as molecular probes to mark FA has important significance in life sciences and pharmaceutical chemistry, which can detect FA as drug efficacy mechanism and the change in physiological activity. In the present paper, we investigated supramolecular assembly and chiral inducement of cyanine dyes template by FA with absorption and circular dichroism (CD) spectra. The result suggests that FA can induce cyanine dyes from J-aggregation to monomer along with different colors change and has strong affinity with cyanine dye monomer.The template of FA not only can translate the chirality of MTC H-aggregation to other two states, but also induce ETC J-aggregation to molecular rearrangement and form left-handed helix of J-aggregates.Besides, the association of PTC with FA, i.e. binding to FA gave rise to the J-aggregation CD signals.Meanwhile, it was inferred that the meso substituent of cyanine dyes play an important role in the interaction between FA and the J-aggregation: the smaller the meso substituent, the higher the affinity interacted with FA.Clearly, the binding abilities between cyanine dyes and FA follow the order of MTC>ETC>PTC.These results support that the cyanine dyes supramolecular aggregates can be used as a kind of excellent molecular probes for specific recognition of FA and achieve the effect of visual inspection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3045 (2014)
Pseudo-Furocoumarin: Synthesis, DNA-Binding Behavior and Cytotoxicity
XIE Li-juan, and CHEN Zhuo
Furocoumarin shows some antitumor activity when it is radiated by the UV light. In order to improve the antitumor activity of furocoumarin under standard environment conditions, the “minimal DNA-intercalating” hypothesis was firstly introduced to the structural modification of furocoumarin, which resulted in the designFurocoumarin shows some antitumor activity when it is radiated by the UV light. In order to improve the antitumor activity of furocoumarin under standard environment conditions, the “minimal DNA-intercalating” hypothesis was firstly introduced to the structural modification of furocoumarin, which resulted in the design of pseudo-furocoumarin.The pseudo-furocoumarin was synthesized by two-step reaction including Pechmann reaction catalyzed by conc. H2SO4 and Suzuki coupling reaction catalyzed by Pd(PPh3)4. The structural character of the pseudo-furocoumarin is that the bonding mode of furan ring fused to the coumarin is replaced by a chemical single bond between furan ring and coumarin. The interaction of the pseudo-furocoumarin with calf thymus DNA (CT-DNA) has been respectively investigated by using DNA melting curve, UV-Vis absorption spectra, fluorescence spectra and viscosity titration, and the modes of DNA-binding for the pseudo-furocoumarin have been proposed. Based on the results of DNA melting curve, spectra and viscosity titration, it was suggested that 5a and 5b bind to DNA by the partial intercalation and classical intercalation, respectively. The DNA-binding behaviors of 5c and 5d have been rarely reported in literature and may be interpreted in terms of bridge-structure. All target compounds, except 5b, show a decreasing capability of intercalation to DNA. Further, the antiproliferative activities of the pseudo-furocoumarin on human lung adenocarcinoma (A549), human breast cancer (MCF-7) and human ovarian carcinoma cell line (SKOV-3) in vitro were evaluated using the sulforhodamine B (SRB) protein statin assay. All pseudo-furocoumarin exhibited an improved anti-proliferative activity as compared with the control compound psoralen (PS, a linear furocoumarin). Interestingly the pseudo-furocoumarin binding to DNA by a non-classical intercalation mode showed a stronger anti-proliferative activity than PS. The present study extended the applied areas of “minimal DNA-intercalating” hypothesis, and provided a method for the structural modification of furocoumarin as well..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3051 (2014)
Application of Optical Flow Dynamic Texture in Land Use/Cover Change Detection
YAN Li, GONG Yi-long, ZHANG Yi, and DUAN Wei
In the present study, a novel change detection approach for high resolution remote sensing images is proposed based on the optical flow dynamic texture (OFDT), which could achieve the land use & land cover change information automatically with a dynamic description of ground-object changes. This paper describes theIn the present study, a novel change detection approach for high resolution remote sensing images is proposed based on the optical flow dynamic texture (OFDT), which could achieve the land use & land cover change information automatically with a dynamic description of ground-object changes. This paper describes the ground-object gradual change process from the principle using optical flow theory, which breaks the ground-object sudden change hypothesis in remote sensing change detection methods in the past. As the steps of this method are simple, it could be integrated in the systems and software such as Land Resource Management and Urban Planning software that needs to find ground-object changes. This method takes into account the temporal dimension feature between remote sensing images, which provides a richer set of information for remote sensing change detection, thereby improving the status that most of the change detection methods are mainly dependent on the spatial dimension information. In this article, optical flow dynamic texture is the basic reflection of changes, and it is used in high resolution remote sensing image support vector machine post-classification change detection, combined with spectral information. The texture in the temporal dimension which is considered in this article has a smaller amount of data than most of the textures in the spatial dimensions. The highly automated texture computing has only one parameter to set, which could relax the onerous manual evaluation present status. The effectiveness of the proposed approach is evaluated with the 2011 and 2012 QuickBird datasets covering Duerbert Mongolian Autonomous County of Daqing City, China. Then, the effects of different optical flow smooth coefficient and the impact on the description of the ground-object changes in the method are deeply analyzed. The experiment result is satisfactory, with an 87.29% overall accuracy and an 0.850 7 Kappa index, and the method achieves better performance than the post-classification change detection methods using spectral information only..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3056 (2014)
Characterization of Structural Change of Ascorbate Peroxidase from Chinese Kale during Denaturation by Circular Dichroism
XI Jia-fu, TANG Lei, ZHANG Jian-hua, ZHANG Hong-jian, CHEN Xu-sheng, and MAO Zhong-gui
Circular dichroism (CD) is a special absorption spectrum. The secondary structure of protein such as α-helix, β-sheet and β-turn in the far ultraviolet region (190～250 nm) has a characteristic CD spectrum. In order to understand the activity and structural changes of ascorbate peroxidase from Chinese kale (BaAPX) durinCircular dichroism (CD) is a special absorption spectrum. The secondary structure of protein such as α-helix, β-sheet and β-turn in the far ultraviolet region (190～250 nm) has a characteristic CD spectrum. In order to understand the activity and structural changes of ascorbate peroxidase from Chinese kale (BaAPX) during denaturation, specific activity and percentage of secondary structure of BaAPX under different time, temperature and concentration were analyzed by CD dynamically. In addition, the percentage of four secondary structures in BaAPX was calculated by CD analysis software Dichroweb. The results show that BaAPX is a full α-type enzyme whose specific activity is positively related to the percentage of α-helix. During denaturation of BaAPX, three kinds of structural changes were proposed: the one-step structural change from initial state (N state) to minimum state of α-helix (R state) under low concentration and low temperature; the one-step structural change from N state to equilibrium state (T state) under high concentration and low temperature; the two-step structural changes from N state through R state to final T state under heat treatment and low temperature renaturation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3062 (2014)
Spectral Quantitative Analysis by Nonlinear Partial Least Squares Based on Neural Network Internal Model for Flue Gas of Thermal Power Plant
CAO Hui, LI Yao-jiang, ZHOU Yan, and WANG Yan-xia
To deal with nonlinear characteristics of spectra data for the thermal power plant flue, a nonlinear partial least square (PLS) analysis method with internal model based on neural network is adopted in the paper. The latent variables of the independent variables and the dependent variables are extracted by PLS regressiTo deal with nonlinear characteristics of spectra data for the thermal power plant flue, a nonlinear partial least square (PLS) analysis method with internal model based on neural network is adopted in the paper. The latent variables of the independent variables and the dependent variables are extracted by PLS regression firstly, and then they are used as the inputs and outputs of neural network respectively to build the nonlinear internal model by train process. For spectra data of flue gases of the thermal power plant, PLS, the nonlinear PLS with the internal model of back propagation neural network (BP-NPLS), the nonlinear PLS with the internal model of radial basis function neural network (RBF-NPLS) and the nonlinear PLS with the internal model of adaptive fuzzy inference system (ANFIS-NPLS) are compared. The root mean square error of prediction (RMSEP) of sulfur dioxide of BP-NPLS, RBF-NPLS and ANFIS-NPLS are reduced by 16.96%, 16.60% and 19.55% than that of PLS, respectively. The RMSEP of nitric oxide of BP-NPLS, RBF-NPLS and ANFIS-NPLS are reduced by 8.60%, 8.47% and 10.09% than that of PLS, respectively. The RMSEP of nitrogen dioxide of BP-NPLS, RBF-NPLS and ANFIS-NPLS are reduced by 2.11%, 3.91% and 3.97% than that of PLS, respectively. Experimental results show that the nonlinear PLS is more suitable for the quantitative analysis of glue gas than PLS. Moreover, by using neural network function which can realize high approximation of nonlinear characteristics, the nonlinear partial least squares method with internal model mentioned in this paper have well predictive capabilities and robustness, and could deal with the limitations of nonlinear partial least squares method with other internal model such as polynomial and spline functions themselves under a certain extent. ANFIS-NPLS has the best performance with the internal model of adaptive fuzzy inference system having ability to learn more and reduce the residuals effectively. Hence, ANFIS-NPLS is an accurate and useful quantitative thermal power plant flue gas analysis method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3066 (2014)
Research on Chemical Oxygen Demand Optical Detection Method Based on the Combination of Multi-Source Spectral Characteristics
WU Guo-qing, and BI Wei-hong
A novel method based on multi-source spectral characteristics of the combination is proposed for chemical oxygen demand detection. First, the ultraviolet and near infrared spectrum of the actual water samples are collected respectively. After pretreatment of the spectrum data, the features of the spectrum are extractedA novel method based on multi-source spectral characteristics of the combination is proposed for chemical oxygen demand detection. First, the ultraviolet and near infrared spectrum of the actual water samples are collected respectively. After pretreatment of the spectrum data, the features of the spectrum are extracted by the nonnegative matrix factorization algorithm for training after normalization. Particle swarm and least squares support vector machines algorithm are applied to predicting chemical oxygen demand of the validation set of water samples. The effect of spectrum’s base number on the predicted results is discussed. The experimental results show that the best base number of the ultraviolet spectrum is 5, the best base number of the near infrared spectrum is 2; The validation set correlation coefficient of the prediction model is 0.999 8, and the root mean square error of prediction is 3.26 mg·L-1. Experimental results demonstrate that the nonnegative matrix factorization algorithm is more suitable for feature extraction of spectral data, and the least squares support vector machines algorithm as a quantitative model correction method of the actual water samples can get good prediction accuracy with different feature extraction methods(principal component analysis, independent component analysis), spectroscopic methods(ultraviolet spectrum method, near infrared spectrum method) and different combination pattern (data direct combination, combining data first, then feature extraction) respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3071 (2014)
Vegetation Index Estimation by Chlorophyll Content of Grassland Based on Spectral Analysis
XIAO Han, CHEN Xiu-wan, YANG Zhen-yu, LI Huai-yu, and ZHU Han
Comparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes thComparing the methods of existing remote sensing research on the estimation of chlorophyll content, the present paper confirms that the vegetation index is one of the most practical and popular research methods. In recent years, the increasingly serious problem of grassland degradation. This paper, firstly, analyzes the measured reflectance spectral curve and its first derivative curve in the grasslands of Songpan, Sichuan and Gongger, Inner Mongolia, conducts correlation analysis between these two spectral curves and chlorophyll content, and finds out the regulation between REP (red edge position) and grassland chlorophyll content, that is, the higher the chlorophyll content is, the higher the REIP (red-edge inflection point) value would be. Then, this paper constructs GCI (grassland chlorophyll index) and selects the most suitable band for retrieval. Finally, this paper calculates the GCI by the use of satellite hyperspectral image, conducts the verification and accuracy analysis of the calculation results compared with chlorophyll content data collected from field of twice experiments. The result shows that for grassland chlorophyll content, GCI has stronger sensitivity than other indices of chlorophyll, and has higher estimation accuracy. GCI is the first proposed to estimate the grassland chlorophyll content, and has wide application potential for the remote sensing retrieval of grassland chlorophyll content. In addition, the grassland chlorophyll content estimation method based on remote sensing retrieval in this paper provides new research ideas for other vegetation biochemical parameters’ estimation, vegetation growth status’ evaluation and grassland ecological environment change’s monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3075 (2014)
Monitoring the Thermal Plume from Coastal Nuclear Power Plant Using Satellite Remote Sensing Data: Modeling and Validation
ZHU Li, ZHAO Li-min, WANG Qiao, ZHANG Ai-ling, WU Chuan-qing, LI Jia-guo, and SHI Ji-xiang
Thermal plume from coastal nuclear power plant is a small-scale human activity, mornitoring of which requires high-frequency and high-spatial remote sensing data. The infrared scanner (IRS), on board of HJ-1B, has an infrared channel IRS4 with 300 m and 4-days as its spatial and temporal resolution. Remote sensing dataThermal plume from coastal nuclear power plant is a small-scale human activity, mornitoring of which requires high-frequency and high-spatial remote sensing data. The infrared scanner (IRS), on board of HJ-1B, has an infrared channel IRS4 with 300 m and 4-days as its spatial and temporal resolution. Remote sensing data aquired using IRS4 is an available source for mornitoring thermal plume. Retrieval pattern for coastal sea surface temperature (SST) was built to monitor the thermal plume from nuclear power plant. The research area is located near Guangdong Daya Bay Nuclear Power Station (GNPS), where synchronized validations were also implemented. The National Centers for Environmental Prediction (NCEP) data was interpolated spatially and temporally. The interpolated data as well as surface weather conditions were subsequently employed into radiative transfer model for the atmospheric correction of IRS4 thermal image. A look-up-table (LUT) was built for the inversion between IRS4 channel radiance and radiometric temperature, and a fitted function was also built from the LUT data for the same purpose. The SST was finally retrieved based on those preprocessing procedures mentioned above. The bulk temperature (BT) of 84 samples distributed near GNPS was shipboard collected synchronically using salinity-temperature-deepness (CTD) instruments. The discrete sample data was surface interpolated and compared with the satellite retrieved SST. Results show that the average BT over the study area is 0.47 ℃ higher than the retrieved skin temperature (ST). For areas far away from outfall, the ST is higher than BT, with differences less than 1.0 ℃. The main driving force for temperature variations in these regions is solar radiation. For areas near outfall, on the contrary, the retrieved ST is lower than BT, and greater differences between the two (meaning >1.0 ℃) happen when it gets closer to the outfall. Unlike the former case, the convective heat transfer resulting from the thermal plume is the primary reason leading to the temperature variations. Temperature rising (TR) distributions obtained from remote sensing data and in-situ measurements are consistent, except that the interpolated BT shows more level details (>5 levels) than that of the ST (up to 4 levels). The areas with higher TR levels (>2) are larger on BT maps, while for lower TR levels (≤2), the two methods perform with no obvious differences. Minimal errors for satellite-derived SST occur regularly around local time 10 a.m. This makes the remote sensing results to be substitutes for in-situ measurements. Therefore, for operational applications of HJ-1B IRS4, remote sensing technique can be a practical approach to monitoring the nuclear plant thermal pollution around this time period..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3079 (2014)
Particles Size Distribution and Its Influence on Remote Sensing Retrieval of Turbid Poyang Lake
HUANG Jue, CHEN Xiao-ling, CHEN Li-qiong, and ZHANG Li
The suspended particle size distribution provides crucial information for the study of water environment structure and function. Based on the in-situ data from wet and dry season in 2008—2011, the paper studied suspended particle size distribution of Poyang Lake and its optical features. The suspended particle size disThe suspended particle size distribution provides crucial information for the study of water environment structure and function. Based on the in-situ data from wet and dry season in 2008—2011, the paper studied suspended particle size distribution of Poyang Lake and its optical features. The suspended particle size distribution showed seasonal variation: the particle size of southern lake was larger than that of northern lake in dry season but showed little variation in wet season. The suspended particle size distribution exerted influence on particulate absorption coefficient, attenuation coefficient and scattering coefficient. The particulate absorption coefficient of northern lake was higher than that of southern lake. The negative correlation between specific absorption coefficient of total suspended particles and median particle size indicated that there was “package effect” of mineral particles in turbid Poyang Lake. The spatial and temporal distribution of particulate attenuation coefficient and scattering coefficient are similar: there were obvious regional differences in dry season but few in wet season. There were good correlations among the remote sensing reflectance, spectra slope of particle size distribution and spectra slope of particulate scattering coefficient. These correlations would provide the foundation for remote sensing retrieval of particle size and quantitative analysis of influence of suspended particle size on the optical properties. The relationship between particle size distribution, particulate backscattering coefficient and bulk refractive index can provide information of particle composition in Poyang Lake..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3085 (2014)
Spectral Reflectance Characteristics of Dominant Plant Species at Different Eco-Restoring Stages in the Semi-Arid Grassland
PENG Yu, MI Kai, QIN Ya, QING Feng-ting, LIU Wei-chen, XUE Da-yuan, and LIU Xue-hua
The objective of the research is to apply hyperspectral technique into eco-restoring monitoring. Through the ASD Fields HH portable field spectrometer, the hyperspectral data of dominant plant species in vegetation at different eco-restoring stages in semi-arid grassland in Helin County, Inner Mongolia were collected. The objective of the research is to apply hyperspectral technique into eco-restoring monitoring. Through the ASD Fields HH portable field spectrometer, the hyperspectral data of dominant plant species in vegetation at different eco-restoring stages in semi-arid grassland in Helin County, Inner Mongolia were collected. The original spectrum reflected data were pretreated by wavelet threshold denoising through ViewSpecPro software before analysis. Using the first derivative spectra between 660 and 800 nm, and the methods of detrended canonical correspondence analysis (DCCA) by Canoco 4.5 software, the canopy hyperspectral datum of 6 dominant plant species was calculated. The results indicated that the dominant plant species at early succession stage were Setaria viridis and Caragana microphylia, at 5 years eco-restoring stage they were Salsola collina and Caragana microphylia and at late succession stage they were Pinus sylvestnis var. mongolica and Salsola collina, same as field survey. The graph of DCCA indicated that the influential bands of dominant species canopy at early eco-succession stage were short bands, with a large variation among species, the influential bands at 5 years eco-restoring stage were near infrared bands between 1 000 and 1 050 nm, and that at late stage were near infrared bands of 1 040～1 075 nm. The DCCA also showed obviously differences in canopy spectrum among 6 dominant species, and obviously differences among 3 eco-restoring stages..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3090 (2014)
Research on Fast Classification Based on LIBS Technology and Principle Component Analyses
YU Qi, MA Xiao-hong, WANG Rui, and ZHAO Hua-feng
Laser-induced breakdown spectroscopy (LIBS) and the principle component analysis(PCA) were combined to study aluminum alloy classification in the present article. Classification experiments were done on thirteen different kinds of standard samples of aluminum alloy which belong to 4 different types, and the results sugLaser-induced breakdown spectroscopy (LIBS) and the principle component analysis(PCA) were combined to study aluminum alloy classification in the present article. Classification experiments were done on thirteen different kinds of standard samples of aluminum alloy which belong to 4 different types, and the results suggested that the LIBS-PCA method can be used to aluminum alloy fast classification. PCA was used to analyze the spectrum data from LIBS experiments, three principle components were figured out that contribute the most, the principle component scores of the spectrums were calculated, and the scores of the spectrums data in three-dimensional coordinates were plotted. It was found that the spectrum sample points show clear convergence phenomenon according to the type of aluminum alloy they belong to. This result ensured the three principle components and the preliminary aluminum alloy type zoning. In order to verify its accuracy, 20 different aluminum alloy samples were used to do the same experiments to verify the aluminum alloy type zoning. The experimental result showed that the spectrum sample points all located in their corresponding area of the aluminum alloy type, and this proved the correctness of the earlier aluminum alloy standard sample type zoning method. Based on this, the identification of unknown type of aluminum alloy can be done. All the experimental results showed that the accuracy of principle component analyses method based on laser-induced breakdown spectroscopy is more than 97.14%, and it can classify the different type effectively. Compared to commonly used chemical methods, laser-induced breakdown spectroscopy can do the detection of the sample in situ and fast with little sample preparation, therefore, using the method of the combination of LIBS and PCA in the areas such as quality testing and on-line industrial controlling can save a lot of time and cost, and improve the efficiency of detection greatly..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3095 (2014)
A Multivariate Nonlinear Model for Quantitative Analysis in Laser-Induced Breakdown Spectroscopy
CHEN Xing-long, FU Hong-bo, WANG Jing-ge, NI Zhi-bo, HE Wen-gan, XU Jun, RAO Rui-zhong, and DONG Feng-zhong
Most quantitative models used in laser-induced breakdown spectroscopy (LIBS) are based on the hypothesis that laser-induced plasma approaches the state of local thermal equilibrium (LTE). However, the local equilibrium is possible only at a specific time segment during the evolution. As the populations of each energy lMost quantitative models used in laser-induced breakdown spectroscopy (LIBS) are based on the hypothesis that laser-induced plasma approaches the state of local thermal equilibrium (LTE). However, the local equilibrium is possible only at a specific time segment during the evolution. As the populations of each energy level does not follow Boltzmann distribution in non-LTE condition, those quantitative models using single spectral line would be inaccurate. A multivariate nonlinear model, in which the LTE is not required, was proposed in this article to reduce the signal fluctuation and improve the accuracy of quantitative analysis. This multivariate nonlinear model was compared with the internal calibration model which is based on the LTE condition. The content of Mn in steel samples was determined by using the two models, respectively. A minor error and a minor relative standard deviation (RSD) were observed in multivariate nonlinear model. This result demonstrates that multivariate nonlinear model can improve measurement accuracy and repeatability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3100 (2014)
Comparative Investigation of Underwater-LIBS Using 532 and 1 064 nm Lasers
SONG Jiao-jian, TIAN Ye, LU Yuan, LI Ying, and ZHENG Rong-er
With the hope of applying laser induced breakdown spectroscopy (LIBS) to the ocean applications, the laser energy at 532 and 1 064 nm wavelength with 3 and 40 mj respectively was used, which was near their breakdown threshold. Extensive experimental investigations of LIBS from CaCl2 water solution were carried out in tWith the hope of applying laser induced breakdown spectroscopy (LIBS) to the ocean applications, the laser energy at 532 and 1 064 nm wavelength with 3 and 40 mj respectively was used, which was near their breakdown threshold. Extensive experimental investigations of LIBS from CaCl2 water solution were carried out in this paper using different laser wavelengths of 532 and 1 064 nm. The obtained results show that compared with the 532 nm laser, the 1 064 nm laser can induce the plasma in water with higher emission intensity and longer lifetime, while the reproducibility of LIBS signal under 1 064 nm laser is poorer. On the other hand, due to the different attenuation ratios of 532 and 1 064 nm laser energies in water, the LIBS signal of 1 064 nm laser decreases a lot within the transmission distance range 2～5 cm, while LIBS signal of 532 nm remains the same, because that the wavelength of 532 nm lies in the "transmission window" of the water solution. This study will provide valuable design considerations for the development of LIBS-sea system in near future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3104 (2014)
Determination of Metal Elements in PM2.5 by ICP-OES with Microwave Digestion
ZHANG Liu-yi, FU Chuan, YANG Fu-mo, YANG Ji-dong, HUANG Yi-min, ZHANG Qiang, and WU Bing-yu
In the present work, a method was developed for determining lead, zinc, copper, cadmium, znd chromium in PM2.5 by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis with microwave digestion and glass fibre filter collection of samples. The microwave digestion systems were investigated and the eIn the present work, a method was developed for determining lead, zinc, copper, cadmium, znd chromium in PM2.5 by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis with microwave digestion and glass fibre filter collection of samples. The microwave digestion systems were investigated and the experimental conditions were optimized. The results show that (1) HNO3-H2O2 digestion system is more stable and complete than HNO3-HCl and HNO3-H2SO4 digestion systems; (2) The most sensitive emission wave length of lead, zinc, copper, cadmium, and chromium are 220.353, 213.857, 327.393, 228.802, and 267.716 nm, respectively; (3) The highest signal-to-noise ratios were observed under the conditions: RF power of 1 300 W, peristaltic pump flow rate of 1.5 mL·min-1, cooling gas flow rate of 15 L·min-1, and carrier gas flow rate of 0.8 L·min-1. In addition, the detection limit for these elements ranged between 2.02×10-3 and 8.20×10-3 μg·mL-1, the relative standard deviations (RSD, n=6) for the samples were in the range of 1.86%～2.82%, and the recovery for the elements determined was from 91.6% to 103.7%. The proposed method was used for determination of the above five elements in atmospheric fine particulate matter at Wanzhou Monitoring Site of Chongqing Institute of Green and Intelligent Technology. The results revealed that the atmospheric fine particulate matter at this monitoring site was not polluted by cadmium and chromium, lead was at the level of potential contamination, while zinc and copper were at the level of slight pollution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3109 (2014)
Comparison of Soil Heavy Metals Determined by AAS/AFS and Portable X-Ray Fluorescence Analysis
RAN Jing, WANG De-jian, WANG Can, BO Lu-ji, ZHENG Ji-cheng, and YAO Li-peng
Total concentrations of Cu, Pb, As, Cr, Ni and Zn were determined for 53 soil samples using portable X-ray fluorescence (PXRF) system in in-situ and ex-situ (Lab.)conditions. PXRF metal concentrations were statistically compared with analytical results from traditional AAS/AFS analysis. The ability of PXRF instrument tTotal concentrations of Cu, Pb, As, Cr, Ni and Zn were determined for 53 soil samples using portable X-ray fluorescence (PXRF) system in in-situ and ex-situ (Lab.)conditions. PXRF metal concentrations were statistically compared with analytical results from traditional AAS/AFS analysis. The ability of PXRF instrument to produce comparable analytical results to the reference method was assessed by linear regression. To investgate the effects of soil moisture on PXRF, the in-situ moisture content of all soil samples was quantified and the metal concentrations of selected samples with known moisture contents were measured too. The results showed that the detection limits of PXRF for Cu, Pb, As, Cr, Ni and Zn were 10.6, 8.1, 5.7, 22.5, 21.6 and 10.4 mg·kg-1, respectively. A good degree of linearity was found for Pb, Cr, Ni and Zn in in-situ condition. While in ex-situ condition, quantitative level data were achieved across the entire range of samples tested for Cu, Pb, Cr, Ni and Zn. X-ray fluorescence spectrometry was shown to be an effective tool for quantification and rapid assessment of heavy metals in soils. Soil moisture content did affected the performance of PXRF, the mean percent difference for soil samples in-situ with moisture content less than 15% and higher than 25% was -17% and -31% respectively. In ex-situ condition, as the soil moisture content increased from air dried level to 30%, the mean percent difference decreased from 10% to -24%. The dilution effect of moisture in soils may cause discrepancies with conventional analytical results and induce worse data quality, and it should be controlled within 0～25% in in-situ condition..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3113 (2014)
X-Ray Powder Diffraction of Clay Minerals of SZK01 Core of Zabuye Lake, Tibetan Plateau
ZHANG Xue-fei, and ZHENG Mian-ping
The present article chooses the core from the borehole SZK01 in Zabuye Lake as the main research object. According to the results of X-ray powder diffraction of clay minerals, the major components are illite, illite and smectite mixed layer mineral(I/S), kaolinite and chlorite. According to the different species and coThe present article chooses the core from the borehole SZK01 in Zabuye Lake as the main research object. According to the results of X-ray powder diffraction of clay minerals, the major components are illite, illite and smectite mixed layer mineral(I/S), kaolinite and chlorite. According to the different species and contents of clay, integration of the characteristics of mineral and the results of δ18O, we reestablished the evolution process of paleoclimate in Zabuye Lake. In compaison with SZK02 core in Zabuye, Greenland GISP2 and GRIP and Guliya ice core, it contains 5 stages since 115 ka in Zabuye: the last interglacial(115～75.5 ka), the earlier last glacial(75.5～60 ka), the interstage of the last glacial(60～30.1 ka), the last glacial maximum(30.1～16.7 ka) and deglacial-holocene(since 16.7 ka). We also recognized 6 Heinrich events (H1-H6) and warm event in 71 ka. In particular, the content of kaolinite is low, with the negative-skewed value of δ18O in 52～53 ka, while the value of δ18O in SZK02 and Guliya ice core is negative-skewed too, indicating the cold event in Tibet plateau, named H5-1. All the above demonstrated that the climate in Tibet plateau is global since the earlier last glacial, and it also has regional characteristics..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3119 (2014)
New Methodology for Heavy Metals Measurement in Water Samples by PGNAA-XRF
JIA Wen-bao, ZHANG Yan*, HEI Da-qian, LING Yong-sheng, SHAN Qing, and CHENG Can
In the present paper, a new combined detection method was proposed using prompt gamma neutron activation analysis (PGNAA) and characteristic X-ray fluorescence to improve the heavy metals measurement accuracy for in-situ environmental water rejects analysis by PGNAA technology. Especially, the characteristic X-ray fluoIn the present paper, a new combined detection method was proposed using prompt gamma neutron activation analysis (PGNAA) and characteristic X-ray fluorescence to improve the heavy metals measurement accuracy for in-situ environmental water rejects analysis by PGNAA technology. Especially, the characteristic X-ray fluorescence (XRF) of heavy metals is induced by prompt gamma-ray directly instead of the traditional excitation sources. Thus, a combined measurement facility with an 241Am-Be neutron source, a BGO detector and a NaI-Be detector was developed to analyze the pollutants in water. The two detectors were respectively used to record prompt gamma-ray and characteristic X-ray fluorescence of heavy metals. The prompt gamma-ray intensity (Iγ) and characteristic X-ray fluorescence intensity (IX) was determined by MCNP calculations for different concentration (ci) of chromium (Cr), cadmium (Cd), mercury (Hg) and lead (Pb), respectively. The simulation results showed that there was a good linear relationship between Iγ, IX and (ｃi), respectively. The empirical formula of combined detection method was given based on the above calculations. It was found that the combined detection method was more sensitive for high atomic number heavy metals like Hg and Pb measurement than low atomic number like Cr and Cd by comparing and analyzing Iγ and IX. The limits of detection for Hg and Pb by the combined measurement instrument were 17.4 and 24.2 mg·kg-1, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3123 (2014)
Atmospheric Parameter Estimation for LAMOST/GUOSHOUJING Spectra
LU Yu, LI Xiang-ru, and YANG Tan
It is a key task to estimate the atmospheric parameters from the observed stellar spectra in exploring the nature of stars and universe. With our Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) which begun its formal Sky Survey in September 2012, we are obtaining a mass of stellar spectra in an unprecIt is a key task to estimate the atmospheric parameters from the observed stellar spectra in exploring the nature of stars and universe. With our Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) which begun its formal Sky Survey in September 2012, we are obtaining a mass of stellar spectra in an unprecedented speed. It has brought a new opportunity and a challenge for the research of galaxies. Due to the complexity of the observing system, the noise in the spectrum is relatively large. At the same time, the preprocessing procedures of spectrum are also not ideal, such as the wavelength calibration and the flow calibration. Therefore, there is a slight distortion of the spectrum. They result in the high difficulty of estimating the atmospheric parameters for the measured stellar spectra. It is one of the important issues to estimate the atmospheric parameters for the massive stellar spectra of LAMOST. The key of this study is how to eliminate noise and improve the accuracy and robustness of estimating the atmospheric parameters for the measured stellar spectra. We propose a regression model for estimating the atmospheric parameters of LAMOST stellar(SVM(lasso)). The basic idea of this model is: First, we use the Haar wavelet to filter spectrum, suppress the adverse effects of the spectral noise and retain the most discrimination information of spectrum. Secondly, We use the lasso algorithm for feature selection and extract the features of strongly correlating with the atmospheric parameters. Finally, the features are input to the support vector regression model for estimating the parameters. Because the model has better tolerance to the slight distortion and the noise of the spectrum, the accuracy of the measurement is improved. To evaluate the feasibility of the above scheme, we conduct experiments extensively on the 33 963 pilot surveys spectrums by LAMOST. The accuracy of three atmospheric parameters is log Teff: 0.006 8 dex, log g: 0.155 1 dex, ［Fe/H］: 0.104 0 dex..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3127 (2014)
The Backgroud Sky Subtraction Around ［OIII］ Line in LAMOST QSO Spectra
SHI Zhi-xin, Georges Comte, LUO A-li, TU Liang-ping, ZHAO Yong-heng, and WU Fu-chao
At present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around ［OIII］ line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem tAt present, most sky-subtraction methods focus on the full spectrum, not the particular location, especially for the backgroud sky around ［OIII］ line which is very important to low redshift quasars. A new method to precisely subtract sky lines in local region is proposed in the present paper, which sloves the problem that the width of Hβ-［OIII］ line is effected by the backgroud sky subtraction. The exprimental results show that, for different redshift quasars, the spectral quality has been significantly improved using our method relative to the original batch program by LAMOST. It provides a complementary solution for the small part of LAMOST spectra which are not well handled by LAMOST 2D pipeline. Meanwhile, This method has been used in searching for candidates of double-peaked Active Galactic Nuclei..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3132 (2014)
A Novel Spatial Modulation Fourier Transform Spectrometer with Adjustable Spectral Resolution
LIAN Yu-sheng, LIAO Ning-fang, LV Hang, WU Wen-min, and DONG Zhi-gang
In the premise of fulfilling the application requirement, the adjustment of spectral resolution can improve efficiency of data acquisition, data processing and data saving. So, by adjusting the spectral resolution, the performance of spectrometer can be improved, and its application range can be extended. To avoid the In the premise of fulfilling the application requirement, the adjustment of spectral resolution can improve efficiency of data acquisition, data processing and data saving. So, by adjusting the spectral resolution, the performance of spectrometer can be improved, and its application range can be extended. To avoid the problems of the fixed spectral resolution of classical Fourier transform spectrometer, a novel type of spatial modulation Fourier transform spectrometer with adjustable spectral resolution is proposed in this paper. The principle of the novel spectrometer and its interferometer is described. The general expressions of the optical path difference and the lateral shear are induced by a ray tracing procedure. The equivalent model of the novel interferometer is analyzed. Meanwhile, the principle of the adjustment of spectral resolution is analyzed. The result shows that the novel spectrometer has the merits of adjustable spectral resolution, high stability, easy assemblage and adjustment etc. This theoretical study will provide the theoretical basis for the design of the spectrometer with adjustable spectral resolution and expand the application range of Fourier transform spectrometer..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3136 (2014)
Analysis of Optic Crosstalk Correction for Pushbroom Hyperspectral Data
TAO Dong-xing, JIA Guo-rui, ZHAO Hui-jie, YUAN Yan, and MA Yan-hua
Based on the imaging process of pushbroom hyperspectral imager, a correction method for optic crosstalk was developed. An area that has white calibration target was selected as reference data. The target pixels crosstalk quantity was gained using the subtraction between the two lines of reference data, and it was fitteBased on the imaging process of pushbroom hyperspectral imager, a correction method for optic crosstalk was developed. An area that has white calibration target was selected as reference data. The target pixels crosstalk quantity was gained using the subtraction between the two lines of reference data, and it was fitted to restrain noise. Using recursion method, crosstalk quantity of single pixel was calculated from the fitted function, and it could be used to correct the optical crosstalk of the whole data. Three PHI (pushbroom hyperspectral imager) data which have different ground scene were corrected. It was showed that optical crosstalk in corrected data is lightened obviously, and the data quality is improved effectively in both the spectral dimension and spatial dimension. The spectral changing caused by optical crosstalk is also corrected, and the bands with definition increased more than 50% accounts for 83% of the total bands. Optic crosstalk is obtained form hyperspectral data itself which is independent of other data source. It is proved that the correction method is valid, and it is applicable for different ground type. The correction method also provides a way to measure the optic crosstalk of hyperspectral imager in the lab..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3141 (2014)
High-Speed Target Recognition Positioning System Based on Multi-Spectral Radiation Characteristics
LI Jian-min, and WANG Gao
In order to achieve quick recognition and positioning of the high-speed target, using multi-spectral radiation combined with acoustic positioning technology, in the passive state, the blast wave spectral characteristics and acoustic characteristics of the measured target were rapidly obtained, thus analysis was performIn order to achieve quick recognition and positioning of the high-speed target, using multi-spectral radiation combined with acoustic positioning technology, in the passive state, the blast wave spectral characteristics and acoustic characteristics of the measured target were rapidly obtained, thus analysis was performed to determine the type, location and other important parameters. Multi-spectral radiation detection target recognition formula was deduced. The accuracy of the optical path length and the logical integration time was calculated by shock acoustic positioning method. Experiments used 5.56 mm NATO bullets, 7.62 mm 56-rifle bullets, 12.7 mm 54 type machine-gun bullets as a target identified projectile. Interference fringes were collected by the static Fourier transform interferometer system and ICX387AL type CCD, and the peak of sound pressure was collected using 2209 pulse sound pressure meter made by B & K Company from Denmark. Experimental results show that for the 5.56 mm NATO bullets, the three characteristic wavelengths position amplitudes are close to each other, with the maximum amplitude at 966 nm; For the 7.62 mm 56-rifle bullets, 935 nm is the maximum amplitude position, while for 966 and 997 nm position the magnitudes are sunukar; For 12.7 mm 54 type machine-gun bullets, the three wavelengths show a ladder-like distribution. With the increase in the detection distance spectral radiation energy decreased. Meanwhile, with the decrease in the total radiation spectrum, the spectrum of target was affected strongly by background noise, and the SNR of system was decreased. But the spectral characteristics of different target still exist, the target species can be identified by the system with the ratio algorithm of characteristic peaks. Through spectral calibration and characteristic wavelengths extraction, the target can successfully identify the type of projectile and target position, and it meets the design requirements..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3147 (2014)
Study of Spectrum Characteristic of Humidity Sensor Based on Series Coupled Two Micro-Ring Resonators
GUO Shi-liang, HU Chun-hai, LI Xin, and WANG Wen-juan
A novel humidity sensor of polyimide(PI) based on the series coupled two-micro-ring resonators is proposed in the present paper. The transfer function of the micro ring resonator was calculated by using the transfer matrix method and the coupled mode theory. The authors compared the output spectrum characteristics of tA novel humidity sensor of polyimide(PI) based on the series coupled two-micro-ring resonators is proposed in the present paper. The transfer function of the micro ring resonator was calculated by using the transfer matrix method and the coupled mode theory. The authors compared the output spectrum characteristics of the traditional single micro-ring and series coupled two-micro-ring with different radii. The refractive index of the PI waveguide changes with different environmental humidity and this will lead to the drift of the output spectrum of the micro-ring resonator. By detecting the drift of the output spectrum we can measure the humidity, and the sensitivity and the sensing-range of the sensor are acquired accordingly. We also analyzed the output spectrum characteristics of resonators at different humidity sensing part. The theoretical results show the good performance of humidity sensor which could be used as the optimum sensing unit when the whole structure of the series coupled two-micro-ring resonators serves as the sensing part. The sensing-range and sensitivity of the system are improved by series micro-ring resonators of different radii compared to the conventional sensor with single micro-ring resonator. The free spectral range (FSR) of resonator reaches to 0.15 μm, the sensing-range is 10%RH～80%RH, and the sensitivity is 0.001 7 μm·(%RH)-1. Series coupled two-micro-ring with different radii gives theoretical instruction for producing integrated humidity sensor with low-cost, simple structure and high sensitivity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3152 (2014)
Effect Evaluation of Optical Magnification Errors for Coded Aperture Spectrometer
MA Yuan, LV Qun-bo, LIU Yang-yang, QIAN Lu-lu, and PEI Lin-lin
In the present paper, we simulated the system optical magnification error's influence on the quality of reconstructed image, analyzed the variant of the coded aperture with different optical magnification, then proposed an accurate curve of image quality and optical magnification in 128×128 code template, whicIn the present paper, we simulated the system optical magnification error's influence on the quality of reconstructed image, analyzed the variant of the coded aperture with different optical magnification, then proposed an accurate curve of image quality and optical magnification in 128×128 code template, which provide important references for the design and development of push-broom coded aperture spectrometer..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3157 (2014)
Characteristics of Phosphorus Fractions in Sediments of Constructed Wetlands
LU Jin, GAO Bo, and HAO Hong
In order to better understand phosphorus (P) cycle in wetland ecosystem, the characteristics of phosphorus fractions in sediments of Heituwa constructed wetland system were investigated using soil organic phosphorus (Po) fractionation scheme and 31P-NMR technology. The concentrations of TP, Pi, Po and soil organic mattIn order to better understand phosphorus (P) cycle in wetland ecosystem, the characteristics of phosphorus fractions in sediments of Heituwa constructed wetland system were investigated using soil organic phosphorus (Po) fractionation scheme and 31P-NMR technology. The concentrations of TP, Pi, Po and soil organic matter were all increased along the flow direction. Four kinds of P-compounds (orthophosphate, orthophosphate monoesters, orthophosphate diesters, and pyrophosphate) were detected in the NMR spectrum. Orthophosphate and phosphate monoester accounted for the dominants position in sediment phosphorus. This study indicates that the Po in sediment plays an importance role in wetland ecosystem and suggested that more attention should be paid to Po, especially to DNA-P and pyrophosphate in further research and management of constructed wetlands. Compared with the traditional chemical analysis method, 31P-NMR method has sample preparation relatively simple and is less destructive, with components analyzed completely. Using 31P-NMR technology, the cognition of wetland phosphorus cycle, especially organophosphate, will be expected to get new breakthrough..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 3162 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 11, 1 (2014)
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