Journals >Spectroscopy and Spectral Analysis
Contents
2013
Volume: 33 Issue 12
56 Article(s)
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Research Article
Label-Free Monitoring 5-FU Induced SW 620 Cells Apoptosis Using FTIR Microspectroscopy
LIU Dong, SUN Xue-jun, ZHANG Chao, HE Sai, DU Jun-kai, HUO Xiong-wei, ZHENG Jian-bao, ZHANG Shi-yun, ZHANG Yuan-fu, XU Yi-zhuang, and WU Jin-guang
The aim of the present study was to evaluate Fourier transform infrared spectroscopy (FTIR) monitoring of biochemical changes in apoptosis cells. Different concentrations of 5-fluorouracil (5-FU) treated colon cancer cell lines SW620 were used to determine the optimum concentration of 5-FU IC50 by means of MTT assay. CThe aim of the present study was to evaluate Fourier transform infrared spectroscopy (FTIR) monitoring of biochemical changes in apoptosis cells. Different concentrations of 5-fluorouracil (5-FU) treated colon cancer cell lines SW620 were used to determine the optimum concentration of 5-FU IC50 by means of MTT assay. Cell starvation and 5-Fu synergistic cell cycle arrest was in G1 and S phase. FTIR combined with flow cytometry was applied to analysis of SW 620 cells and SW620 cells treated with 5-FU for 12h, 24h (early apoptosis) and 48 h (late apoptosis) respectively. The peak position and the intensity of all bands were measured and comparison was made between the SW620 and apoptotic SW620 cells. Apoptosis cells have following characteristics compared with SW620 cells (1) The band at 1 740 cm-1 is an CO stretching vibration. Changes in these bands can reflect lipid changes, and relative peak intensity ratio I1 740/I1 460 significantly increased (p<0.05), indicating that the relative contents of lipid in apoptosis cells increased. (2) The band at the 1 410 cm-1 peak represents that C-H stretching related was increased to amino acid residues and shifted to higher wave numbers compared to other groups. I1 410/I1 460 at early and late death phase was significantly increased, which suggests that the relative contents of amino acid residues in apoptosis cells increased (p<0.05). New vibrational bands at 1 120 cm-1 appeared at 24 h and increased at 48 h compared with other groups. The 1 120 cm-1 absorption band is mainly due to ser, serine and threonine C-O(H) stretching vibration, and I1 120/I1 460 significantly increased (p<0.05), indicating that the relative quantity of amino acid residues in apoptosis cells increased due to that DNA unwinds the double helix. (3) 1 240 cm-1 is mainly due to the asymmetric stretching modes of phosphodiester groups shifting to higher wave number, illustrating that nucleic acid conformation was changed in apoptosis cells. (4) The band 1 040 cm-1 associated with polysaccharide appeared at 24 and 48 h, meanwhile shifted to higher wave number, suggesting that polysaccharide decreased in late apoptotic cells, and I1 040/I1 460 increased at late stage apoptosis, indicating that the relative content of polysaccharide in apoptosis cells increased. The authors’ results suggest that FTIR applied to monitoring SW620 cells apoptosis may be as a potential diagnostic tool for cancer chemotherapy monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3169 (2013)
A Dye Densitometry Analysis Method for Noninvasive Measurement of Cardiac Output Based on NIRS
LU Meng-meng, WANG Hong-xuan, LIU Guang-da, XIN Gui-jie, YU Yong, and ZHA Yu-tong
Currently, there exist technology problems in cardiac output (CO) parameter detection clinically, such as invasive and complex operation, as well as possibility of infection and death for patients. In order to solve these problems, a noninvasive and continuous method based on NIRS for CO detection was presented. In thiCurrently, there exist technology problems in cardiac output (CO) parameter detection clinically, such as invasive and complex operation, as well as possibility of infection and death for patients. In order to solve these problems, a noninvasive and continuous method based on NIRS for CO detection was presented. In this way, the concentration changing of indocyanine green (ICG) dye in the patient’s arterial blood was dynamically measured and analyzed, so that the CO could be noninvasively and continuously measured according to the characteristic parameters of dye densitometry curve. While the ICG dye was injected into the patient’s body by the median cubital vein, block of photoelectric pulse dye densitometry measurement system as the lower machine acquired pulse wave data and uploaded the data to upper computer. In the scheme, two specialized light sources of LED at 940 and 805 nm were used to capture the signals of sufferer’s fingertip pulse wave synchronously and successively. The CO value could then be successfully calculated through drawing complete ICG concentration variation of dye dilution and excretion process and computing mean transmission time (MTT) by upper computer. Compared with the “gold standard” method of thermodilution, the maximum relative error of this method was below 9.76%, and the mean relative error was below 4.39%. The result indicates that the method can be used as a kind of convenient operation, noninvasive and continuous solution for clinical CO measurement..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3175 (2013)
The Lambert-Beer’s Law Characterization of Formal Analysis in Terahertz Spectrum Quantitative Testing
SU Hai-xia, ZHANG Zhao-hui, ZHAO Xiao-yan, LI Zhi, YAN Fang, and ZHANG Han
The present paper discusses the Lambert-Beer’s law application in the terahertz spectrum, studies the single amino acid tablet sample (glutamine) and two kinds of amino acids mixture tablet (threonine and cystine) under the condition of different concentrations. Absorbance and absorption coefficient was analyzed in theThe present paper discusses the Lambert-Beer’s law application in the terahertz spectrum, studies the single amino acid tablet sample (glutamine) and two kinds of amino acids mixture tablet (threonine and cystine) under the condition of different concentrations. Absorbance and absorption coefficient was analyzed in the description of the terahertz optical properties of matter. By comparing absorption coefficient and absorbance value of the single component in the vicinity of 1.72 THz, we verified the material under two kinds of absorption characterization of quantity of THz wave absorption along with the change in the concentration. Using the index of goodness of fit R2, it studied the stand or fall of linear relationship between the terahertz absorption quantity of material and concentration under two kinds of representation. This paper analyzes the two components mixture under two kinds of absorption characterization of quantity of terahertz absorption in 0.3～2.6 THz. Using the similarity coefficient and the estimate concentration error as evaluation index, it has been clear that the absorbance of additivity instead of the absorption coefficient should be used during the terahertz spectrum quantitative test, and the Lambert-Beer’s law application in the terahertz wave band was further clarified..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3180 (2013)
Experimental Research on Optimization of QEPAS Based Spectrophone
ZHENG Hua-dan, DONG Lei, LIU Yan-yan, WU Hong-peng, ZHANG Lei, MA Wei-guang, YIN Wang-bao, and JIA Suo-tang
The present paper studied the impact of geometry dimensions, located angle and detection position of a quartz tuning fork (QTF) on the sensitivity of QEPAS system. Ten kinds of QTFs were employed to compare the sensitivity with each other, and the results show that the QTF with a wedge-shape top obtains a higher qualitThe present paper studied the impact of geometry dimensions, located angle and detection position of a quartz tuning fork (QTF) on the sensitivity of QEPAS system. Ten kinds of QTFs were employed to compare the sensitivity with each other, and the results show that the QTF with a wedge-shape top obtains a higher quality factor and turns to be 50% more sensitive than the ones with a regular cuboid top when detecting the water concentration at 7 306 cm-1. By studying the located angle of a QTF, it was found that it nearly makes no difference, but more noise is introduced when there is an angle φ between the laser beam and QTF. The optimal detection position of a QTF appears to be 3.1 cm away from the bottom of the QTF under the case of the normal incidence. At last the influence of external contamination on the resonant frequency of a QTF is discussed. The authors found that the frequency of the QTF decreases along with the contamination increasing. A novel method to lower the frequency of the QTF is proposed. This may make a contribution to the QEPAS used in detecting trace gas with a low V-T relaxation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3187 (2013)
Study on the Conductivity Properties of Lightning Channel by Spectroscopy
WANG Xue-juan, YUAN Ping, CEN Jian-yong, WANG Jie, and ZHANG Ting-long
Combining the spectra of cloud-to-ground lightning return obtained by a slit-less spectrograph with the transport theory of air plasma, the electrical conductivity in one discharge channel was calculated with different methods. The results show that the conductivity of the lightning channel core is of the order of 104 Combining the spectra of cloud-to-ground lightning return obtained by a slit-less spectrograph with the transport theory of air plasma, the electrical conductivity in one discharge channel was calculated with different methods. The results show that the conductivity of the lightning channel core is of the order of 104 S·m-1; the conductivity goes down with the increase in the channel height in the same channel; the contributions of the collisions between electron and first or second degree ionized atoms, and electron-electron as well as ion-ion collisions to the electrical conductivity of the lightning channel core can not be neglected; the collision integrals method is more reasonable for calculating the conductivity of the lightning channel core. Based on the conductivity, the discharge current was estimated and compared with the peak current of every return stroke, and the results are in the reasonable range, further, the correlation between the channel temperature and the discharge characteristics is discussed, which provides a practical way for this aspect..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3192 (2013)
Effects of Different Annealing Conditions on the Photoluminescence of Nanoporous Alumina Film
XIE Ning, MA Kai-di, SHEN Yi-fan, and WANG Qian
The nanoporous alumina films were prepared by two-step anodic oxidation in 0.5 mol·L-1 oxalic acid electrolyte at 40 V. Photoluminescence (PL) of nanoporous alumina films was investigated under different annealing atmosphere and different temperature. The authors got three results about the PL measurements. In theThe nanoporous alumina films were prepared by two-step anodic oxidation in 0.5 mol·L-1 oxalic acid electrolyte at 40 V. Photoluminescence (PL) of nanoporous alumina films was investigated under different annealing atmosphere and different temperature. The authors got three results about the PL measurements. In the same annealing atmosphere, when the annealling temperature T≤600 ℃, the intensity of the PL peak increases with elevated annealing temperature and reaches a maximum value at 500 ℃, but the intensity decreases with a further increase in the annealing temperature, and the PL peak intensity of samples increases with the increase in the annealing temperature when the annealling temperature T≥800 ℃. In the different annealling atmosphere, the change in the photoluminescence peak position for nanoporous alumina films with the increase in the annealing temperature is different: With the increase in the annealling temperature, the PL peak position for the samples annealed in air atmosphere is blue shifted, while the PL peak position for the samples annealed in vacuum atmosphere will not change. The PL spectra of nanoporous alumina films annealed at 1 100 ℃ in air atmosphere can be de-convoluted by three Gaussian components at an excitation wavelength of 350 nm, with bands centered at 387, 410 and 439 nm, respectively. These results suggest that there might be three luminescence centers for the PL of annealed alumina films. At the same annealling temperature, the PL peak intensity of samples annealed in air atmosphere is stronger than that annealed in the vacuum. Based on the experimental results and the X-ray dispersive energy spectrum (EDS) combined with infrared reflect spectra, the luminescence mechanisms of nanoporous alumina films are discussed. There are three luminescence centers in the annealed nanoporous alumina films, which originate from the F center, F+ center and the center associated with the oxalic impurities. The effects of different annealing conditions on the photoluminescence of nanoporous alumina film are reasonably explained..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3197 (2013)
Photochromic Properties of Complexes of Curcumin Aniline Schiff Base with Rare Earth
SONG Yu-min, YANG Mei-ling, MA Jun-huai, and ZHANG Yu-mei
Using Ce, La, Nd (Ⅲ) nitrate and a curcumin aniline schiff base and a curcumin bis (4-methyl aniline) schiff base as raw materials, six complexes were synthesized. Through the molar conductance, IR, TG-DTA and element analysis motheds, the structures of complexes were characterized. Moreover, the properties of UV-VisibUsing Ce, La, Nd (Ⅲ) nitrate and a curcumin aniline schiff base and a curcumin bis (4-methyl aniline) schiff base as raw materials, six complexes were synthesized. Through the molar conductance, IR, TG-DTA and element analysis motheds, the structures of complexes were characterized. Moreover, the properties of UV-Visible spectra and photochromic properties of the complex, and the solvate-chromic performance in organic solvents were explored. The experiments showed that the complexes have good photochromic and solvate-chromic properties. The fluorescence intensity and UV-Visible spectra intensity were reduced under exposure, and the color of the complex solution became light. The complexes have different UV-Visible spectra in difference organic solvents. The relationship between photochromic properties and time was also studied..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3202 (2013)
The Research Progress in Determining Lignocellulosic Content by Near Infrared Reflectance Spectroscopy Technology
DU Juan, AN Dong, XIA Tian, HUANG Yan-hua, LI Hong-chao, and ZHANG Yun-wei
Near infrared reflectance spectroscopy technology, as a new analytic method, can be used to determine the content of lignin, cellulose and hemi-cellulose which is faster, effective, easier to operate, and more accurate than the traditional wet chemical methods. Nowadays it has been widely used in measuring the compositNear infrared reflectance spectroscopy technology, as a new analytic method, can be used to determine the content of lignin, cellulose and hemi-cellulose which is faster, effective, easier to operate, and more accurate than the traditional wet chemical methods. Nowadays it has been widely used in measuring the composition of lignocelluloses in woody plant and herbaceous plant. The domestic and foreign research progress in determining the lignin, cellulose and hemi-cellulose content in woody plant ( wood and bamboo used as papermaking raw materials and wood served as potential biomass energy) and herbaceous plant (forage grass and energy grass) by near infrared reflectance spectroscopy technology is comprehensively summarized and the advances in method studies of measuring the composition of lignocelluloses by near infrared reflectance spectroscopy technology are summed up in three aspects, sample preparation, spectral data pretreatment and wavelength selection methods, and chemometric analysis respectively. Four outlooks are proposed combining the development statues of wood, forage grass and energy grass industry. First of all, the authors need to establish more feasible and applicable models for a variety of uses which can be used for more species from different areas, periods and anatomical parts. Secondly, comprehensive near infrared reflectance spectroscopy data base of grass products quality index needs to be improved to realize on-line quality and process control in grassproducts industry, which can guarantee the quality of the grass product. Thirdly, the near infrared reflectance spectroscopy quality index model of energy plant need to be built which can not only contribute to breed screening, but also improve the development of biomass industry. Besides, modeling approaches are required to be explored and perfected any further. Finally, the authors need to try our best to boost the advancement in the determination method of lignin, cellulose and hemi-cellulose by near infrared reflectance spectroscopy from the laboratory to the practical applications. Along with the method of determining the lignin, cellulose and hemi-cellulose by near infrared spectroscopy being unceasingly perfected and matured, this technique will actively have a positive effect on the development of papermaking, forage grass and energy grass industry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3207 (2013)
Research on Preprocessing Method of Near-Infrared Spectroscopy Detection of Coal Ash Calorific Value
ZHANG Lin, LU Hui-shan, YAN Hong-wei, GAO Qiang, WANG Fu-jie, and SONG Hai-yan
The calorific value of coal ash is an important indicator to evaluate the coal quality. In the experiment, the effect of spectrum and processing methods such as smoothing, differential processing, multiplicative scatter correction (MSC) and standard normal variate (SNV) in improving the near-infrared diffuse reflectionThe calorific value of coal ash is an important indicator to evaluate the coal quality. In the experiment, the effect of spectrum and processing methods such as smoothing, differential processing, multiplicative scatter correction (MSC) and standard normal variate (SNV) in improving the near-infrared diffuse reflection spectrum signal-noise ratio was analyzed first, then partial least squares (PLS) and principal component analysis (PCR) were used to establish the calorific value model of coal ash for the spectrums processed with each preprocessing method respectively. It was found that the model performance can be obviously improved with 5-point smoothing processing, MSC and SNV, in which 5-point smoothing processing has the best effect, the coefficient of association, correction standard deviation and forecast standard deviation are respectively 0.989 9, 0.000 49 and 0.000 52, and when 25-point smoothing processing is adopted, over-smoothing occurs, which worsens the model performance, while the model established with the spectrum after differential preprocessing has no obvious change and the influence on the model is not large..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3212 (2013)
Detection of Reducing Sugar Content of Potato Granules Based on Wavelet Compression by Near Infrared Spectroscopy
DONG Xiao-ling, and SUN Xu-dong
The feasibility was explored in determination of reducing sugar content of potato granules based on wavelet compression algorithm combined with near-infrared spectroscopy. The spectra of 250 potato granules samples were recorded by Fourier transform near-infrared spectrometer in the range of 4 000～10 000 cm-1. The threThe feasibility was explored in determination of reducing sugar content of potato granules based on wavelet compression algorithm combined with near-infrared spectroscopy. The spectra of 250 potato granules samples were recorded by Fourier transform near-infrared spectrometer in the range of 4 000～10 000 cm-1. The three parameters of vanishing moments, wavelet coefficients and principal component factor were optimized. The optimization results of three parameters were 10, 100 and 20, respectively. The original spectra of 1 501 spectral variables were transfered to 100 wavelet coefficients using db wavelet function. The partial least squares (PLS) calibration models were developed by 1 501 spectral variables and 100 wavelet coefficients. Sixty two unknown samples of prediction set were applied to evaluate the performance of PLS models. By comparison, the optimal result was obtained by wavelet compression combined with PLS calibration model. The correlation coefficient of prediction and root mean square error of prediction were 0.98 and 0.181%, respectively. Experimental results show that the dimensions of spectral data were reduced, scarcely losing effective information by wavelet compression algorithm combined with near-infrared spectroscopy technology in determination of reducing sugar in potato granules. The PLS model is simplified, and the predictive ability is improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3216 (2013)
Discrimination of Bamboo Using FTIR Spectroscopy and Statistical Analysis
LI Lun, LIU Gang, ZHANG Chuan-yun, OU Quan-hong, ZHANG Li, and ZHAO Xing-xiang
Fourier transform infrared (FTIR) spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify and classify bamboo leaves. FTIR spectra of fifty-four bamboo leaf samples belonging to six species were obtained. The results showed that the infrared spectra ofFourier transform infrared (FTIR) spectroscopy combined with principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify and classify bamboo leaves. FTIR spectra of fifty-four bamboo leaf samples belonging to six species were obtained. The results showed that the infrared spectra of bamboo leaves were similar, and mainly composed of the bands of polysaccharides, protein and lipids. The original spectra exhibit minor differences in the region of 1 800~700cm-1. The second derivative spectra show apparent differences in the same region. Principal component analysis and hierarchical cluster analysis were performed on the second derivative infrared spectra in the range from 1 800 to 700 cm-1. The leaf samples were separated into 6 groups with accuracy of 98% with the first three principal components, and with 100% accuracy according to the third and fourth principal components. Hierarchical cluster analysis can correctly cluster the bamboo leaf samples. It is proved that Fourier transform infrared spectroscopy combined with PCA and HCA could be used to discriminate bamboo at species level with only a tiny leaf sample..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3221 (2013)
Establishment of the Model for Online Monitoring of the Column Separation and Purification Process by Near-Infrared Spectroscopy and Determination of Total Ginsenosides in Folium Ginseng
LIU Hua, ZHAO Xin, QI Tian, QI Yun-peng, and FAN Guo-rong
A method was developed for online monitoring of the constituents of ginsenoside of Folium Ginseng in the column separation and purification process using near-infrared (NIR) spectroscopy technology. Determination method of ginsenoside Rg1, Re and Rb1 was developed by high performance liquid chromatography (HPLC). AfterA method was developed for online monitoring of the constituents of ginsenoside of Folium Ginseng in the column separation and purification process using near-infrared (NIR) spectroscopy technology. Determination method of ginsenoside Rg1, Re and Rb1 was developed by high performance liquid chromatography (HPLC). After collecting 40%-ethanol eluant, their NIR spectra were detected and the contents of Rg1, Re and Rb1 were determined by the above HPLC method. The quantitative analysis models of the above three compounds and the total ginsenosides were established using partial least squares (PLS). During modeling, coefficient of determination (R2) and root mean square errors of cross-validation (RMSECV) were regarded as the indexes to select optimal wave numbers and preprocessing methods. The optimal wave numbers of ginsenoside Rg1, Re, Rb1 and total ginsenosides were all in the range of 12 000.8~7 499.8 cm-1; R2 were 0.988 7, 0.960 3, 0.990 5 and 0.970 1, respectively; RMSECV were 0.059 7, 0.072 2, 0.004 88 and 0.075 5, respectively. A lot of samples, collected during the column separation and purification process of Folium Ginseng extract, were used to validate the predicttion effect of quantitative analysis model of total ginsenosides. As a result, the correlation coefficient of NIR predicted value and HPLC value of total ginsenosides was 0.992 8 and the mean prediction recovery was 100.52%, which indicated that the prediction effect of the developed model was satisfactory. This method was proved to be fast, convenient and precise. It can be used for assaying and quality control of total ginsenosides in manufacture..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3226 (2013)
Discrimination of the Fresh Jujube Varieties and Dehiscent Fruit by NIR Spectroscopy
HU Yao-hua, LIU Cong, and HE Yong
There are many fresh jujube varieties. The different variety has different quality. In addition, dehiscent fruit easily rot and the rotten fruit contaminated the full fruit very rapidly. It is necessary to discriminate the jujube varieties and dehiscent fruit to reduce the storage loss. The objective is to discriminateThere are many fresh jujube varieties. The different variety has different quality. In addition, dehiscent fruit easily rot and the rotten fruit contaminated the full fruit very rapidly. It is necessary to discriminate the jujube varieties and dehiscent fruit to reduce the storage loss. The objective is to discriminate varieties and dehiscent Fruit of fresh jujube using near infrared (NIR) spectroscopy. Two jujube varieties were investigated. Smoothing, multiplicative scatter correction, the first derivative and second derivative methods were adopted to pretreat the spectra. The regression coefficient and principal component analysis were used to select wavenumber. Multilayer perceptron artificial neural network was used to build varieties and dehiscent fruit qualitative discrimination model. The results showed that the varieties and dehiscent fruit could be correctly discriminated and both the discrimination accuracy rates were 100%. Hence, near infrared spectroscopy could achieve to identify the variety of Dongzao and Lizao, and dehiscent fruit and intact fruit..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3231 (2013)
Determination of Soluble Solids Content in Nanfeng Mandarin by Vis/NIR Spectroscopy and UVE-ICA-LS-SVM
SUN Tong, XU Wen-li, HU Tian, and LIU Mu-hua
The objective of the present research was to assess soluble solids content (SSC) of Nanfeng mandarin by visible/near infrared (Vis/NIR) spectroscopy combined with new variable selection method, simplify prediction model and improve the performance of prediction model for SSC of Nanfeng mandarin. A total of 300 Nanfeng The objective of the present research was to assess soluble solids content (SSC) of Nanfeng mandarin by visible/near infrared (Vis/NIR) spectroscopy combined with new variable selection method, simplify prediction model and improve the performance of prediction model for SSC of Nanfeng mandarin. A total of 300 Nanfeng mandarin samples were used, the numbers of Nanfeng mandarin samples in calibration, validation and prediction sets were 150, 75 and 75, respectively. Vis/NIR spectra of Nanfeng mandarin samples were acquired by a QualitySpec spectrometer in the wavelength range of 350~1 000 nm. Uninformative variables elimination (UVE) was used to eliminate wavelength variables that had few information of SSC, then independent component analysis (ICA) was used to extract independent components (ICs) from spectra that eliminated uninformative wavelength variables. At last, least squares support vector machine (LS-SVM) was used to develop calibration models for SSC of Nanfeng mandarin using extracted ICs, and 75 prediction samples that had not been used for model development were used to evaluate the performance of SSC model of Nanfeng mandarin. The results indicate that Vis/NIR spectroscopy combined with UVE-ICA-LS-SVM is suitable for assessing SSC of Nanfeng mandarin, and the precision of prediction is high. UVE-ICA is an effective method to eliminate uninformative wavelength variables, extract important spectral information, simplify prediction model and improve the performance of prediction model. The SSC model developed by UVE-ICA-LS-SVM is superior to that developed by PLS, PCA-LS-SVM or ICA-LS-SVM, and the coefficient of determination and root mean square error in calibration, validation and prediction sets were 0.978, 0.230%, 0.965, 0.301% and 0.967, 0.292%, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3235 (2013)
Raman Spectra of Oleic Acid and Linoleic Acid
FAN Ya, LI Shuang, and XU Da-peng
Different unsaturated fatty acids have different physiological functions, however, the common fatty acid products are mostly mixture of several unsaturated fatty acids. Thus it is necessary to analyze the composition of impure fatty acid products before application. In the present article, the Raman spectra of oleic acDifferent unsaturated fatty acids have different physiological functions, however, the common fatty acid products are mostly mixture of several unsaturated fatty acids. Thus it is necessary to analyze the composition of impure fatty acid products before application. In the present article, the Raman spectra of oleic acid and linoleic acid (the most commonly appearing components of fatty acid products) were measured. Furthermore, the mode assignments of the Raman bands were determined and the molecular conformational characters were analyzed. The results lay the groundwork for researching the energy level structures and transitions of long-chain unsaturated fatty acids and enrich the valence bond data of organic molecules. In addition, the differences between the Raman spectra of oleic acid and linoleic acid were analyzed in detail, which provides a convenient and effective method for their identification and has directive significance for the application of Raman spectroscopy in hogwash oil detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3240 (2013)
Surface-Enhanced Raman Scattering of Thiabendazole Adsorbed on Silver Nanoparticles
CHEN Lin, YANG Xiao-gang, ZHENG Xu-ming, and PEI Ke-mei
In the present paper, quantum chemistry calculations method based on the density functional theory (DFT) and surface-enhanced Raman scattering (SERS) spectroscopy technique were used to investigate the adsorption behavior and enhancement effect of thiabendazole on the nanometer silver colloid surface systematically froIn the present paper, quantum chemistry calculations method based on the density functional theory (DFT) and surface-enhanced Raman scattering (SERS) spectroscopy technique were used to investigate the adsorption behavior and enhancement effect of thiabendazole on the nanometer silver colloid surface systematically from theoretical and experimental perspective. By sodium citrate’s reduction reaction, nanometer silver colloid with has high surface-enhanced Raman scattering activity was prepared. And then the authors studied the surface-enhanced Raman scattering spectroscopy of the thiabendazole in aqueous solution. The authors carried on the detailed quantum chemistry calculations for the interaction between thiabendazole and nanometer silver colloid, using the TBZ-Ag4 model to get the adsorption properties of thiabendazole molecule on nanometer silver colloid. Combining FT-Raman spectrum with the theoretical calculation results by the B3LYP/6-311G(d) theoretical level, and the visualization of GaussianView5.0 software, the FT-Raman vibration spectrum and the surface-enhanced Raman scattering spectroscopy of thiabendazole molecule were assigned systematically. All the theoretical and experimental results show that all atoms of thiabendazole are in one plane and the point group of thiabendazole is Cs; Thiabendazole has high surface-enhanced Raman scattering activity on nanometer silver colloid surface; the thiabendazole is absorbed on silver colloid particles by S atom, and the long axis of thiabendazole molecule is perpendicular to the nanometer silver colloid surface; the trace concentration of thiabendazole can be detected rapidly and effectively with the surface-enhanced Raman scattering spectroscopy technique. This work provides a theoretical and experimental basis for the study of thiabendazole’s characteristics and its rapid detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3244 (2013)
Study on Heavy Metals and Ecological Risk Assessment from Gansu, Ningxia and Inner Mongolia Sections of the Yellow River, China
LIU Jing-jun, and LIU Ying
The Yellow River is the most important resource of water supply in northern China. The purpose of this work are to investigate the concentrations and potential ecological risk of heavy metals in the upper reaches of the Yellow River, the concentrations of eight heavy metals including As, Hg, Cd, Pb, Cr, Ni, Cu and Zn iThe Yellow River is the most important resource of water supply in northern China. The purpose of this work are to investigate the concentrations and potential ecological risk of heavy metals in the upper reaches of the Yellow River, the concentrations of eight heavy metals including As, Hg, Cd, Pb, Cr, Ni, Cu and Zn in filtered water and suspended particles from 12 sampling sites of Gansu, Ningxia and Inner Mongolia sections of the Yellow River of China were studied by atomic fluorescence spectrometry (AFS) and high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) in this paper. The results implied that all heavy metals in filtered water were lower than the limit standards for drinking water except for Cr (56.9～71.5 μg·L-1). Water quality parameters such as total nitrogen (TN), total phosphorus (TP) and pH were also determined and the contents were low along the river except for TN at S1 (2.48) and S9 (2.38), which exceeded the maximum permitted concentration of Class Ⅴ for the protection of surface water. In suspended particles, the concentrations of Hg, Cd, Pb and Zn were much higher than those in the background value of soil from local section. Cluster analysis (CA) indicated that same sources for Ni, Cu, Cr, Zn and Pb could be stainless steel and petrochemical industrial activities, while As, Cd and Hg derived from agrochemicals, fertilizers, mining, fuel and coal combustion, respectively. Ecological risk assessment was undertaken using risk index (RI) for sampling sites and ecological risk factor (Er) for heavy metals. Eleven suspension samples existed considerable ecological risk (300.6
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3249 (2013)
EEMD De-Noising Adaptively in Raman Spectroscopy
ZHAO Xiao-yu, FANG Yi-ming, WANG Zhi-gang, and ZHAI Zhe
It is well known that the second generation wavelet is the best de-noising means, but the result of de-noising depends on how to set up the basis function, decomposition layers and threshold parameters. Without parameter setting empirical mode decomposition (EMD) decomposes the signal into intrinsic mode functions (IMFIt is well known that the second generation wavelet is the best de-noising means, but the result of de-noising depends on how to set up the basis function, decomposition layers and threshold parameters. Without parameter setting empirical mode decomposition (EMD) decomposes the signal into intrinsic mode functions (IMF), then structuring IMF filter and the de-noising process is adaptive. It is worth noting that the signal and the noise are mixed together in very high frequency, that is to say that there has been mode overlap, and what happened will affect the de-noising effect. It was found that ensemble empirical mode decomposition (EEMD) decomposes Raman spectrum into the signal and the noise effectively avoiding from mode overlap in high frequency in the experiments, and it is similar with wavelet in de-nosing effect fortunately. At first, a period of non-linear and non-smooth bean greases Raman spectrum was decomposed by EMD in the paper, there was mode overlap, but the authors have got clear characteristic components by EEMD. Secondly noisy spectrum was processed by fast Fourier transform (FFT), wavelet, EMD and EEMD independently, and signal to noise ratio, root mean square error and correlation coefficient indicate that FFT is the worse means in high frequency de-noising than EMD, and the appropriate wavelet is similar with EEMD in de-noising result, but the de-noising process of EEMD is adaptive. In the last section, a brief research direction of the spectrum study method in time frequency field and noise properties criterion on IMF are given for the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3255 (2013)
Synthesis and Theoretical Study on Fluorescence Property of 4-(2-Hydroxybenzylideneamino)Phenyl Ethanone Schiff Base
LIANG Xiao-rui, WANG Gang, JIANG Yan-lan, QU Cheng-li, WANG Xiu-juan, and ZHAO Bo
Using salicylaldehyde and 4-aminophenyl ethanone as raw material, a Schiff base derivative 4-(2-hydroxybenzylideneamino)phenyl ethanone was synthesized by the solid phase reaction method at room temperature. The structure of the product was characterized by elemental analysis and 1HNMR. The UV spectra, fluorescence emiUsing salicylaldehyde and 4-aminophenyl ethanone as raw material, a Schiff base derivative 4-(2-hydroxybenzylideneamino)phenyl ethanone was synthesized by the solid phase reaction method at room temperature. The structure of the product was characterized by elemental analysis and 1HNMR. The UV spectra, fluorescence emission spectra and fluorescence quantum yield of the title Schiff base derivative were investigated. The results showed that this Schiff base displayed superior fluorescence property. The ground state configuration of the title Schiff base was optimized by density functional theory (DFT) method at the B3LYP/6-311G level. After vibrational analysis, there is no imaginary frequency, which indicates that the structure is stable. Then the ground state configuration was optimized to the excited state configuration by the method of single excited interactions CIS. Based on the optimized structure for the ground state and excited state time-dependent density functional theory (TD-DFT) calculations were carried out at the B3LYP/6-31G level to predict the absorption spectra and the fluorescence spectra. The results show that the computed spectra were comparable with the spectra from the experiments. The relationship between the molecular structure and the fluorescence property of 4-(2-hydroxybenzylideneamino)phenyl ethanone was also discussed. The results obtained may provide some theoretical guidance for the design of new fluorescence compounds..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3259 (2013)
Comparison of Three-Dimensional Fluorescence Characteristics of Two Isomers: Phenanthrene and Anthrancene
YIN Dan-dan, WU Jing, XIE Chao-bo, CAO Zhi-ping, LV Qing, and ZHANG Ren-quan
In recent years, three-dimensional fluorescence spectrometry has been widely used to study the transportation and transformation of the environment pollutants. But little understanding about the relationship between fluorescence characteristics and molecular structure restricts its application. In the present paper, thIn recent years, three-dimensional fluorescence spectrometry has been widely used to study the transportation and transformation of the environment pollutants. But little understanding about the relationship between fluorescence characteristics and molecular structure restricts its application. In the present paper, the excitation-emission matrix (EEM) of the typical aromatic pollutants and isomers, phenanthrene and anthracene were studied. The result showed that there existed a peak locating at λex/λem=225/340 nm in the EEM of both phenanthrene and anthracene. Furthermore, the peaks at 275/360 nm of phenanthrene located quite close to the peak of anthracene at 285/360 nm. However, the difference between the EEM of phenanthrene and anthracene was significant. There existed the third fluorescence peak at 275/340 nm and the most intensive peak at 225/340 nm in the EEM of phenanthrene. The EEM of anthracene was more complicated. The most intensive peaks located at λex/λem=250/380, 250/400 and 250/425 nm respectiveoy. In addition, the fluorescence intensity of anthracene at 225/340 nm was about 1.63 times that of phenanthrene when their concentrations were about 0.058 1 mg·L-1. The orbital energy gap of the frontier molecules of phenanthrene and anthracene were 4.779 and 3.621 eV respectively according to the density functional theory. Owe to the smaller energy gap and better symmetry of electron cloud, anthracene was easier to be excited under the excitation of longer wavelength with higher fluorescence intensity. The density functional theory is a good tool to estimate the luminous capability of organic matters..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3263 (2013)
Study on CO2 Measurement Using Tunable Multi-Mode Diode Laser Absorption Spectroscopy
GAO Guang-zhen, CHEN Bao-xue, HU Bo, LONG Xiu-hui, LI Ai-ping, and LI Rong
Tunable diode laser absorption spectroscopy (TDLAS) technology is a kind of fast time response, large-range, continuous on-line monitoring gas detection technique. It is the mainstream technology of gas detection. In this paper the multimode laser diode was used as light source. Multi-mode laser combined with correlatiTunable diode laser absorption spectroscopy (TDLAS) technology is a kind of fast time response, large-range, continuous on-line monitoring gas detection technique. It is the mainstream technology of gas detection. In this paper the multimode laser diode was used as light source. Multi-mode laser combined with correlation spectroscopy can improve the test reliability and stability. It can also conquer the problem of the central wavelength change of the single mode diode laser due to thermal or mechanical fluctuations in durable working process. A FP laser was used as the light source in this research. A multi-mode diode laser system based on correlation spectroscopy and wavelength modulation spectroscopy (TMDL-COSPEC-WMS) was used to measure carbon dioxide in ambient air around 1 570 nm. The carbon dioxide concentrations were derived from the relationship between the normalized WMS-2f signal peak heights of the measurement and reference signals which selected based on high signal to noise ratio and correlation coefficient. All measurements were performed with controlled carbon dioxide and nitrogen mixtures in which carbon dioxide concentrations range from 0.6% to 30%. The calculation results showed that there was a high linear relationship between the measured and actual carbon dioxide concentration, the linearity was 0.998 7 and the fitted slope was 1.061±0.016 8 respectively over the tested range. A detection limit of 335 ppm·m was achieved. The standard deviation of 0.036 7% was achieved using 20 successive measurements with each measurement time taking ~10 s during 20 minutes, which demonstrated good stability of the system. Good agreements between the measurements of the system and actual values confirm the accuracy and potential utility of the system for carbon dioxide detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3269 (2013)
Study on the Axial Strain Sensor of Birefringence Photonic Crystal Fiber Loop Mirror Based on the Absolute Integral of the Monitoring Peak
JIANG Ying, ZENG Jie, LIANG Da-kai, WANG Xue-liang, NI Xiao-yu, ZHANG Xiao-yan, LI Ji-feng, and LUO Wen-yong
In the present paper, the theoretical expression of the wavelength change and the axial strain of birefringence fiber loop mirror is developed. The theoretical result shows that the axial strain sensitivity of birefringence photonic crystal fiber loop mirror is much lower than conventional birefringence fiber loop mirrIn the present paper, the theoretical expression of the wavelength change and the axial strain of birefringence fiber loop mirror is developed. The theoretical result shows that the axial strain sensitivity of birefringence photonic crystal fiber loop mirror is much lower than conventional birefringence fiber loop mirror. It is difficult to measure the axial strain by monitoring the wavelength change of birefringence photonic crystal fiber loop mirror, and it is easy to cause the measurement error because the output spectrum is not perfectly smooth. The different strain spectrum of birefringence photonic crystal fiber loop mirror was measured experimentally by an optical spectrum analyzer. The measured spectrum was analysed. The results show that the absolute integral of the monitoring peak decreases with increasing strain and the absolute integral is linear versus strain. Based on the above results, it is proposed that the axial strain can be measured by monitoring the absolute integral of the monitoring peak in this paper. The absolute integral of the monitoring peak is a comprehensive index which can indicate the light intensity of different wavelength. This method of monitoring the absolute integral of the monitoring peak to measure the axial strain can not only overcome the difficulty of monitoring the wavelength change of birefringence photonic crystal fiber loop mirror, but also reduce the measurement error caused by the unsmooth output spectrum..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3273 (2013)
Research on Several Times of Abruptly Changes in the Ultrafast Transient Reflectivity in Co Films
XU Xiao-fang, GAO Yong-feng, LV Liu, CAO Xiang-xiang, REN Nai-fei, and ZHOU Ming
In the present paper, cobalt films, chromium and cobalt double layer films, and silver and cobalt double layer films were deposited by magnetron sputtering technique. The transient reflectivity response in cobalt thin films and their double layer films was studied by using femtosecond laser pump-probe transient reflectIn the present paper, cobalt films, chromium and cobalt double layer films, and silver and cobalt double layer films were deposited by magnetron sputtering technique. The transient reflectivity response in cobalt thin films and their double layer films was studied by using femtosecond laser pump-probe transient reflection experimental technology. The result shows that, under the condition of the cobalt films of the same thickness, when the pump power increases, the heating time of the electrons in cobalt thin films is independent of the pump power, and is 0.134 4 ps. And for the cobalt films of different thickness, the electron thermalization time is directly related to the film thickness. In addition, when the laser pulse power is high enough, two or three transient reflectivity decline signals on glass substrate films are found which is different with previous researches, when the cobalt films were thin, there are three times of transient reflectivity abruptly decline signals, and when the cobalt films were thick, there are two times of transient reflectivity abruptly decline signals, so the thickness of the cobalt films determines the times of the changes of the ultrafast dynamics in cobalt films..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3278 (2013)
Study of Relation between Crushed Lava Spectrum and Magnetic Susceptibility in Xiangshan Uranium Orefield
WU Zhi-chun, GUO Fu-sheng, LIU Lin-qing, and JIANG Yong-biao
Rock spectrum research is the base of the remote sensing geology. It’s of great significance of exploring the relations between rock spectrum and other rock natures. In the present study, 36 fine crushed lava samples each measuring 5 cm×5 cm×5 cm were tested for its spectrums by SVC HR-768 portable spectrometRock spectrum research is the base of the remote sensing geology. It’s of great significance of exploring the relations between rock spectrum and other rock natures. In the present study, 36 fine crushed lava samples each measuring 5 cm×5 cm×5 cm were tested for its spectrums by SVC HR-768 portable spectrometer. But before measuring each sample, white boards should be calibrated and after measuring the curves of spectrum of each sample should make a 5 nm smooth resample so that meteoric water and noise caused by external environment can be eliminated. After such smooth resample, at the spectrum scope of 1 112~1 322 nm, taking band value as horizontal axis and reflectivity as vertical axis, linear equations of rock samples can be obtained. Taking the slopes as the horizontal axis and volume magnetic susceptibility as vertical axis, y=-0.256 3ln(x)+0.913 7 was thus obtained and its equation correlation coefficient is up to 0.78. The result shows that volume magnetic susceptibility is mainly caused by Fe2+, and that the amount of Fe2+ can be almost measured in the spectrum scope of 1 112~1 322 nm that has a good correlation with volume magnetic susceptibility..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3282 (2013)
Characterizing Chromophoric Dissolved Organic Matter (CDOM) in Lake Honghu, Lake Donghu and Lake Liangzihu Using Excitation-Emission Matrices (EEMs) Fluorescence and Parallel Factor Analysis (PARAFAC)
ZHOU Yong-qiang, ZHANG Yun-lin, NIU Cheng, and WANG Ming-zhu
Little is known about DOM characteristics in medium to large sized lakes located in the middle and lower reaches of Yangtze River, like Lake Honghu, Lake Donghu and Lake Liangzihu. Absorption, fluorescence and composition characteristics of chromophoric dissolved organic matter (CDOM) are presented using the absorptionLittle is known about DOM characteristics in medium to large sized lakes located in the middle and lower reaches of Yangtze River, like Lake Honghu, Lake Donghu and Lake Liangzihu. Absorption, fluorescence and composition characteristics of chromophoric dissolved organic matter (CDOM) are presented using the absorption spectroscopy, the excitation-emission matrices (EEMs) fluorescence and parallel factor analysis (PARAFAC) model based on the data collected in Sep.-Oct. 2007 including 15, 9 and 10 samplings in Lake Honghu, Lake Donghu and Lake Liangzihu, respectively. CDOM absorption coefficient at 350 nm a(350) coefficient in Lake Honghu was significantly higher than those in Lake Donghu and Lake Liangzihu (t-test, p<0.001). A significant negative correlation was found between CDOM spectral slope in the wavelength range of 280～500 nm (S280～500) and a(350) (R2=0.781, p<0.001). The mean value of S280～500 in Lake Honghu was significantly lower than those in Lake Donghu (t-test, p<0.01) and Lake Liangzihu (t-test, p<0.001). The mean value of spectral slope ratio SR in Lake Honghu was also significantly lower than those in Lake Donghu and Lake Liangzihu (t-test, p<0.05). Two humic-like (C1, C2) and two protein-like fluorescent components (C3, C4) were identified by PARAFAC model, among which significant positive correlations were found between C1 and C2 (R2=0.884, p<0.001), C3 and C4 (R2=0.677, p<0.001), respectively, suggesting that the sources of the two humic-like components as well as the two protein-like components were similar. However, no significant correlation has been found between those 4 fluorescent components and DOC concentration. The fluorescence indices of FI255(HIX), FI265, FI310(BIX) and FI370 in Lake Donghu were all significantly higher than those in Lake Liangzihu (t-test, p<0.05) and Lake Honghu (t-test, p<0.01), indicating that the eutrophication status in Lake Donghu was higher than Lake Honghu and Lake Liangzihu..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3286 (2013)
Research on the Spectral Analysis and Stability of Copper Green
LI Man, WANG Li-qin, XIA Yin, and YANG Qiu-ying
In the history of Chinese pigment, copper green, a pigment, was used in vast territory and for a long time. In the present paper, the nature, spectral characteristics, thermodynamic stability of the four isomers of the basic copper chlorides and also their application in the polychrome relics were discussed. The four iIn the history of Chinese pigment, copper green, a pigment, was used in vast territory and for a long time. In the present paper, the nature, spectral characteristics, thermodynamic stability of the four isomers of the basic copper chlorides and also their application in the polychrome relics were discussed. The four isomers can be identified quickly by Raman spectral analysis which is a micro-damage or even a nondestructive technique. The order of their thermodynamic stability is as follows: clinoatacamite＞paratacamite＞atacamite＞botallackite. It was showed that in the relics samples copper green was mostly botallackite and atacamite which were less stable isomers. According to the Ostwald step rule, the environmental monitoring should be strengthened to prevent the change in their physical and chemical structures..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3293 (2013)
Change of LAI and Spectral Response for Rice under Flood and Waterlogging Stress
XU Peng, GU Xiao-he, MENG Lu-min, QIU He, and WANG Hui-fang
In order to provide the foundational theoretical support for flood loss estimation of rice with RS, the change of leaf area index (LAI) and canopy spectral response during four developmental stages and three waterlogging depths were studied, and the LAI estimation model was established with spectra characteristics paraIn order to provide the foundational theoretical support for flood loss estimation of rice with RS, the change of leaf area index (LAI) and canopy spectral response during four developmental stages and three waterlogging depths were studied, and the LAI estimation model was established with spectra characteristics parameter using regression analysis method. The results show that LAI value decreases as water depth increases in tillering, jointing and heading stages, and LAI value under complete submergence decreased by 36.36% than CK in jointing stages. “Double-Peak” presented in the canopy first derivative spectra of 680~760 nm where the red edge parameters existed, and the main peak is located in the 724~737 nm with 701 and 718 nm exhibiting secondary peak. With water depth increasing, “Triple-Peak” emerges especially. The red edge position moves to long-wavelength direction in each developmental stage. Blue shift of red edge amplitude and red edge area was detected in tillering, jointing and filling stages, while red shift appeared in heading stage. The relationship between spectra characteristics parameters and LAI were investigated during 4 growth stages, results were not consistently significant at any wavelengths, and the leaf area indices were significantly correlative to the spectra parameters before heading stage, so the spectra parameters before heading stage can be used to estimate the leaf area indices, and a regression model based on parameter Dλ737/Dλ718 was recommended. Therefore the variation range of LAI for rice could response to the stress intensity directly, and the regression model LAI=3.138(Dλ737/Dλ718)-0.806 can precisely estimate the leaf area index under flooding and waterlogging stress..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3298 (2013)
The Changes of Forest Canopy Spectral Reflectance with Seasons in Xiaoxing’anling
XU Guang-cai, PANG Yong, LI Zeng-yuan, ZHAO Kai-rui, and LIU Lu-xia
The ASD FieldSpec portable spectrometer was adopted to collect canopy reflectance spectrum data of the 9 main tree species in study area by a long-term observation to get the data of the four seasons Then the smoothed reflectance curve and the first derivation curve from 350 to 1 400 nm and several commonly used vegetaThe ASD FieldSpec portable spectrometer was adopted to collect canopy reflectance spectrum data of the 9 main tree species in study area by a long-term observation to get the data of the four seasons Then the smoothed reflectance curve and the first derivation curve from 350 to 1 400 nm and several commonly used vegetation spectral characteristic parameters were generated to analyse seasonal change characteristics and variation of the 9 tree species in visible and near-infrared band and to explore the best band characteristics and period for species identification. The results showed that different trees had different and rather unique spectral features during the four seasons. The spectral characteristics of the deciduous trees have regular changes with the cycle of the seasons, whereas those of the evergreen tree species have no significant changes in one year. As well changes in the spectral characteristics could effectively reflect forest phenology changes, and it is proposed that the optimal strategy for tree species classification may be the integration and analysis of multi-seasonal spectral data. Evergreen trees and deciduous trees in the winter have obvious differences in the canopy spectral characteristics and the best single-season remote sensing data for tree species recognition is in summer..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3303 (2013)
Research on Formaldehyde Concentration Detection System Based on Photo-Elastic Modulation
LI Yang-jun, JIAO Ning, WANG Rui-jun, LEI Shu-feng, and WANG Gao
There is a growing number of environmental pollution caused by excessive indoor formaldehyde, and in order to quickly and accurately quantify the concentration of formaldehyde gas in indoor air, a system for detecting the concentration of formaldehyde gas based on photo-elastic modulation was designed. It consists of tThere is a growing number of environmental pollution caused by excessive indoor formaldehyde, and in order to quickly and accurately quantify the concentration of formaldehyde gas in indoor air, a system for detecting the concentration of formaldehyde gas based on photo-elastic modulation was designed. It consists of the infrared light source, filters, elastic light modulator, and infrared detectors, and photo-elastic crystal refractive index of cyclical changes was controlled by elastic light modulator. Refractive index caused by the changes in the optical path provided a spectrum distribution function of the optical path difference. Optical path difference function of the system was derived through the HITRAN spectral database. Experiments were carried out using infrared light source combined with narrow band filters, and the transmittance of the center wavelength was more than 90%. Photo-elastic crystal is ZnSe crystal as photo-elastic light modulator, and the drive frequency of the system is 100 kHz. For three different environments at different locations, 10 groups of sample gas were collected for analysis, and the concentration of formaldehyde gas was detected using standard spectrometer and the system for comparing the test data. Experimental results show that when the concentration of formaldehyde gas is high, the system performance is good; When the concentration of formaldehyde gas is low, the signal-to-noise ratio of the system is decreased, and the detection accuracy is slightly reduced, but it still meets the design requirements..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3308 (2013)
Spectra Analysis of Dissolved Organic Matter in Pretreatment Process of Leachate Treated by Reverse Osmosis
ZENG Xiao-lan, HAN Le, LIU Jian-dong, DING Wen-chuan, ZHANG Qin, and JIANG An
In order to examine the removal of organic matter in the leachate which results in reverse osmosis (RO) membrane fouling, and to provides a reference to select appropriate pretreatment processes of RO, synchronous-scan fluorescence, three-dimensional excitation emission matrix fluorescence spectroscopic and UV-Vis specIn order to examine the removal of organic matter in the leachate which results in reverse osmosis (RO) membrane fouling, and to provides a reference to select appropriate pretreatment processes of RO, synchronous-scan fluorescence, three-dimensional excitation emission matrix fluorescence spectroscopic and UV-Vis spectrum of the dissolved organic matter (DOM) in different molecular weight range in effluent from each leachate process of “biochemical (UASB+A/O)and UF” pretreatment in some incineration plant were examined. The results of synchronous fluorescence spectra analysis showed that DOM in the wavelength range of 250～320 nm with all the molecular weight and in the wavelength>320 nm with molecular weight>1 KDa was removed obviously by the pretreatment processes. The results of three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectra showed that the pretreatment processes removed low-excitation wavelength tyrosine-like, low-excitation wavelength tryptophan-like and high-excitation wavelength tryptophan-like with all the molecular weight off, and fulvic-like matter and high-excitation wave length tyrosine-like with molecular weight>1 KDa effectively. The results of UV-Vis spectra analysis showed that the pretreatment processes removed DOM of molecular weight>1 KDa with π-π* transition and DOM of all molecular weight with conjugated system of the benzene ring structure. It was concluded that the removal of both fulvic-like matter and high-excitation wave length tyrosine-like with the wavelength>320 nm, molecular weight<1 KDa and with π-π* transition should be strengthened for controlling (RO) membrane fouling, when leachate was treated by RO with the pretreatment processes of “biochemical(UASB+A/O)and UF”..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3312 (2013)
Quantitative Analysis of Content and Spectrum of Altered Mineral in the Oil and Gas Microseepage Area
LI Qian-qian, CHEN Xiao-mei, LIU Xing, and NI Guo-qiang
With the Yulin Prefecture in China as the research area and the mineral compositions and reflectance spectra of 119 samples collected in the research area as research data, the present paper analyzes the correlation between the carbonate content of surface altered minerals caused by oil and gas microseepage and such chWith the Yulin Prefecture in China as the research area and the mineral compositions and reflectance spectra of 119 samples collected in the research area as research data, the present paper analyzes the correlation between the carbonate content of surface altered minerals caused by oil and gas microseepage and such charactersitic parameters of depth, width of its spectral absorption peak, establishes and evaluates a method for determining carbonate content, and proposes a new method for characterizing the degree of oil and gas microseepage by using the carbonate content. Research results show that this method is not only suitable for characterizing the oil and gas microseepage degree of carbonates, but also suitable for studying the oil and gas microseepage degree of other types of altered minerals. Therefore, the method can provide reference for studying oil and gas exploration technology by using spectral information of hyperspectral remote sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3318 (2013)
Analysis of EDS Fingerprint Spectra of Mineral Drug Montmorillonite Powder Relying on Dual Index Grade Sequence Individualized Pattern Recognition Method and their Quickly Quality Evaluation
ZOU Hua-bin, Ayiguzaili·Ablimiti, and ZHAI Hong
EDS(energy dispersive spectrometer)element fingerprint spectra is able to quickly measure the kinds and the contents of elements in any mineral drug. In dual index grade sequence individualized pattern recognition method, common (quantity) index and variation (quantity) index ratios of any two samples’ fingerprint specEDS(energy dispersive spectrometer)element fingerprint spectra is able to quickly measure the kinds and the contents of elements in any mineral drug. In dual index grade sequence individualized pattern recognition method, common (quantity) index and variation (quantity) index ratios of any two samples’ fingerprint spectra are calculated, and the individualized dual index sequence of each sample is constructed relying on its own EDS fingerprint spectra as the reference. Then the mean common (quantity) index ratio and the standard deviation S of all samples in each sample’s individualized dual index sequence are computed. On this basis, for each sample, its own similarity scale function P≥+xS is built up. By this function, the optimum x suitable for optimized classification/cluster of all samples is determined, and the individualized characteristics sequence of one sample, to which samples in the individualized characteristics sequence are significantly similar, is decided also. Finally, depending on these individualized characteristics sequences, the optimized classification/cluster of all samples can be carried out perfectly without any prior knowledge related to them. This method is not only suitable for the quantitative analysis on fingerprint spectra being of only common peaks, but also fits for that being of both common and variant peaks. In this study, the EDS element fingerprint spectra of seven mineral drug montmorillonite powder samples from different companies were detected. Then common (quantity) index and variant (quantity) index ratios of peak area (or contents of majorly active element Fe, Al, Ca, Mg, Si) among different EDS fingerprint spectra were obtained. In the similarity scale function P≥+xS, when x=0.5, these seven mineral drug montmorillonite powder samples could be quickly identified with high resolution, be classified into two groups, and their quality could be evaluated precisely. In general EDS element fingerprint spectra combined with dual index grade sequence individualized pattern recognition method offers a novel approach to quickly identifying mineral drugs with high resolution and for accurately quantitative quality evaluation of them, based on atomic content information provide by EDS fingerprint spectra..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3321 (2013)
Study on High Accuracy Detection of Multi-Component Gas in Oil-Immerse Power Transformer
FAN Jie, CHEN Xiao, HUANG Qi-feng, ZHOU Yu, and CHEN Gang
In order to solve the problem of low accuracy and mutual interference in multi-component gas detection, a kind of multi-component gas detection network with high accuracy was designed. A semiconductor laser with narrow bandwidth was utilized as light source and a novel long-path gas cell was also used in this system. BIn order to solve the problem of low accuracy and mutual interference in multi-component gas detection, a kind of multi-component gas detection network with high accuracy was designed. A semiconductor laser with narrow bandwidth was utilized as light source and a novel long-path gas cell was also used in this system. By taking the single sine signal to modulate the spectrum of laser and using space division multiplexing (SDM) and time division multiplexing (TDM) technique, the detection of multi-component gas was achieved. The experiments indicate that the linearity relevance coefficient is 0.99 and the measurement relative error is less than 4%. The system dynamic response time is less than 15 s, by filling a volume of multi-component gas into the gas cell gradually. The system has advantages of high accuracy and quick response, which can be used in the fault gas on-line monitoring for power transformers in real time..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3326 (2013)
Characterization and Spectral Analysis of the Stable Mineral Phases α,β-FeOOH Included in Iron Oxyhydroxides
XU Yi-qun, YANG Ming, HE Cheng-da, and XIONG Hui-xin
In the present work, based on the stable phase of α-FeOOH and β-FeOOH easily formed in ferric solutions of Fe(NO3)3 and FeCl3 at the appropriate pH values, respectively, the phase and crystallizability, morphologies and sizes for the particles of FeOOH minerals prepared under the conditions of heating at 40 and 70 ℃, aIn the present work, based on the stable phase of α-FeOOH and β-FeOOH easily formed in ferric solutions of Fe(NO3)3 and FeCl3 at the appropriate pH values, respectively, the phase and crystallizability, morphologies and sizes for the particles of FeOOH minerals prepared under the conditions of heating at 40 and 70 ℃, and magnetic stirring at 25 ℃ were identified and examined by X-ray diffraction (XRD), transmission/scanning electron microscopy (TEM/SEM) and laser scattering particle analyzer. Meanwhile the surface chemistry properties were also detected and analyzed by Fourier transform infrared spectrometer (FTIR). Investigation results showed that the prepared minerals Gth-T70 (α-FeOOH), Aka-T40 and Aka-T70 (β-FeOOH) have good properties of nanocrystallity, homogeneous particles and higher specific surface areas, which induced that the above α, β-FeOOH are potentially excellent adsorbent materials for removal of some contaminants in circumstances..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3330 (2013)
Nitrogen Status Diagnosis and Yield Prediction of Spring Maize after Green Manure Incorporation by Using a Digital Camera
BAI Jin-shun, CAO Wei-dong, XIONG Jing, ZENG Nao-hua, Shimizu Katshyoshi, and RUI Yu-kui
In order to explore the feasibility of using the image processing technology to diagnose the nitrogen status and to predict the maize yield, a field experiment with different nitrogen rates with green manure incorporation was conducted. Maize canopy digital images over a range of growth stages were captured by digital In order to explore the feasibility of using the image processing technology to diagnose the nitrogen status and to predict the maize yield, a field experiment with different nitrogen rates with green manure incorporation was conducted. Maize canopy digital images over a range of growth stages were captured by digital camera. Maize nitrogen status and the relationships between image color indices derived by digital camera for maize at different growth stages and maize nitrogen status indicators were analyzed. These digital camera sourced image color indices at different growth stages for maize were also regressed with maize grain yield at maturity. The results showed that the plant nitrogen status for maize was improved by green manure application. The leaf chlorophyll content (SPAD value), aboveground biomass and nitrogen uptake for green manure treatments at different maize growth stages were all higher than that for chemical fertilization treatments. The correlations between spectral indices with plant nitrogen indicators for maize affected by green manure application were weaker than that affected by chemical fertilization. And the correlation coefficients for green manure application were ranged with the maize growth stages changes. The best spectral indices for diagnosis of plant nitrogen status after green manure incorporation were normalized blue value (B/(R+G+B)) at 12-leaf (V12) stage and normalized red value (R/(R+G+B)) at grain-filling (R4) stage individually. The coefficients of determination based on linear regression were 0.45 and 0.46 for B/(R+G+B) at V12 stage and R/(R+G+B) at R4 stage respectively, acting as a predictor of maize yield response to nitrogen affected by green manure incorporation. Our findings suggested that digital image technique could be a potential tool for in-season prediction of the nitrogen status and grain yield for maize after green manure incorporation when the suitable growth stages and spectral indices for diagnosis were selected..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3334 (2013)
Review of Change Detection Methods Using Multi-Temporal Remotely Sensed Images
YIN Shou-jing, WU Chuan-qing, WANG Qiao, MA Wan-dong, ZHU Li, YAO Yan-juan, WANG Xue-lei, and WU Di
With the development of platforms and sensors, continuous repetition of remote sensing observation of the earth surface has been realized, and a mass of multi-source, multi-scale, multi-resolution remote sensing data has been accumulated. Those images have detailedly recorded the changing process of ground objects on tWith the development of platforms and sensors, continuous repetition of remote sensing observation of the earth surface has been realized, and a mass of multi-source, multi-scale, multi-resolution remote sensing data has been accumulated. Those images have detailedly recorded the changing process of ground objects on the earth, which makes the long term global change research, such as change detection, based on remote sensing become possible, and greatly push forward the research on image processing and application. Although plenty of successful research has been reported, there are still enormous challenges in multi-temporal imagery change detection. A relatively complete mature theoretical system has not formed, and there is still a lack of systematic summary of research progress. Firstly, the current progress in change detection methods using multi-temporal remotely sensed imagery has been reviewed in this paper. Then, the methods are classified into three categories and summarized according to the type and amount of the input data, single-phase post-classification comparison, two-phase comparison, and time series analysis. After that, the possible existing problems in the current development of multi-temporal change detection are analyzed, and the development trend is discussed finally..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3339 (2013)
Application of Hyper-Spectral Remote Sensing Technology in Environmental Protection
ZHAO Shao-hua, ZHANG Feng, WANG Qiao, YAO Yun-jun, WANG Zhong-ting, and YOU Dai-an
Hyper-spectral remote sensing (RS) technology has been widely used in environmental protection. The present work introduces its recent application in the RS monitoring of pollution gas, green-house gas, algal bloom, water quality of catch water environment, safety of drinking water sources, biodiversity, vegetation claHyper-spectral remote sensing (RS) technology has been widely used in environmental protection. The present work introduces its recent application in the RS monitoring of pollution gas, green-house gas, algal bloom, water quality of catch water environment, safety of drinking water sources, biodiversity, vegetation classification, soil pollution, and so on. Finally, issues such as scarce hyper-spectral satellites, the limits of data processing and information extract are related. Some proposals are also presented, including developing subsequent satellites of HJ-1 satellite with differential optical absorption spectroscopy, greenhouse gas spectroscopy and hyper-spectral imager, strengthening the study of hyper-spectral data processing and information extraction, and promoting the construction of environmental application system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3343 (2013)
A Technique for Generating Natural Color Images Based on Local Endmembers
ZHOU Ya-nan, LUO Jian-cheng, SHEN Zhan-feng, CHENG Xi, and HU Xiao-dong
A method for generating natural color composite of satellite images based on local endmembers of ground features was proposed. First, the reference satellite image which has similar land cover types with the target satellite image is segmented into multiple local patches. Secondly, endmembers of ground features are extA method for generating natural color composite of satellite images based on local endmembers of ground features was proposed. First, the reference satellite image which has similar land cover types with the target satellite image is segmented into multiple local patches. Secondly, endmembers of ground features are extracted from each local patch, then we choose better endmembers and gather them into a sample set. Thirdly, we use the sample set to build up the relationship between the spectral values of the blue band and the other bands. Finally, the spectrum relationship is used to generate natural color composite of the target image. The verification experiment on Landsat TM5 images shows that the proposed method is reliable and stable to generate the natural color composite of images. The other experiment on IRS-P6 images shows that our method is able to promote for other satellite images. In experiments, we also compared the existing “reference image-image” method and “spectral library-image” method qualitatively and quantificationally, indicating that our method is more precise to simulate spectrums of all kinds of ground features..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3349 (2013)
Prediction Models of Soil Organic Matter Based on Spectral Curve in the Upstream of Heihe Basin
LIU Jiao, LI Yi, and LIU Shi-bin
Benefiting from the high spectral resolution, ground hyperspectral remote sensing technology can express the ground surface feature in detail, meanwhile, multispectral remote sensing has more advantages in studying the features in a large space-time region, because of its long time-series images and wide coverage. InveBenefiting from the high spectral resolution, ground hyperspectral remote sensing technology can express the ground surface feature in detail, meanwhile, multispectral remote sensing has more advantages in studying the features in a large space-time region, because of its long time-series images and wide coverage. Investigating the prediction models between the soil organic matter (SOM) content and the hyperspectral data and the sensitive bands based on different indices mathematically obtained from reflectance could combine the advantages of both kinds of spectral data, and provide a new method to search the spatio-temporal characteristics of SOM. Two hundred twenty three soil samples were chosen from the upper reaches of Heihe Basin to measure the SOM content and hyperspectral curve. Taking 181 of them, the stepwise linear regression methods were used to establish models between the SOM and five indices, including reflectance (λ), reciprocal (REC), logarithm of the reciprocal (LR), continuum-removal (CR) and the first derivative reflectance (FDR). After then, the left 42 samples were used for model validation: firstly, the best model of the same index was chosen by the values of Pearson correlation coefficient (r) and Root mean squared error (RMSE) between the measured value and predicted value; secondly, the best models of different indices were compared. As a result, the model built by reflectance has a better estimation of SOM with the r: 0.863 and RMSE: 4.79. And the sensitive bands of the reflectance model contain 474 nm during TM1, 636 nm during TM3 and 1 632 nm during TM5. This result could be a reference for the retrieval of SOM content of the upper reaches by using the TM remote sensing data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3354 (2013)
Construction of Vegetation Shadow Index (SVI) and Application Effects in Four Remote Sensing Images
XU Zhang-hua, LIU Jian, YU Kun-yong, LIU Tao, GONG Cong-hong, TANG Meng-ya, XIE Wan-jun, and LI Zeng-lu
Taking the images of Landsat TM, ALOS AVNIR-2, CBERS-02B CCD and HJ-1 CCD as the experimental data, for increasing the differences among shaded area, bright area and water further, the present paper construed a novel vegetation index-Shaded Vegetation Index(SVI), which can not only keep the absolute differences among bTaking the images of Landsat TM, ALOS AVNIR-2, CBERS-02B CCD and HJ-1 CCD as the experimental data, for increasing the differences among shaded area, bright area and water further, the present paper construed a novel vegetation index-Shaded Vegetation Index(SVI), which can not only keep the absolute differences among bright area, shaded area and water area in the near-infrared band, but also can enlarge NDVI, eliminate the possible mixes, and change the histogram “skewed” phenomenon of NDVI, so the vegetation index value is closer to normal distribution, and more in line with the filed condition; this new index was applied to the surface features of large difference of the near-infrared radiation characteristics. Verified by accuracy assessment for the bright area, shaded area and water area recognition effects with SVI, it was showed that the overall classification accuracies of these images were up to 98.89%, 100%, 97.78% and 97.78% respectively, with the overall Kappa statistics of 0.983 3, 1, 0.966 7, and 0.966 7, indicating that SVI has excellent detection effects for bright area, shaded area and water area; the statistical comparison of sub-images between SVI and NDVI also illustrated the reliability and effectiveness of SVI, which can be applied in the shadow removal for remote sensing images..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3359 (2013)
Comparative Study of Transmission and Reflection Hyperspectral Imaging Technology for Potato Damage Detection
GAO Hai-long, LI Xiao-yu, XU Sen-miao, TAO Hai-long, LI Xiao-jin, and SUN Jin-feng
The randomly placed damage parts of potato will affect the detection accuracy, this paper used transmission and reflection hyperspectral imaging technology to acquire potato images of three directions(the damage part facing to the camera, back to the camera, side to the camera), and then processed the comparative studyThe randomly placed damage parts of potato will affect the detection accuracy, this paper used transmission and reflection hyperspectral imaging technology to acquire potato images of three directions(the damage part facing to the camera, back to the camera, side to the camera), and then processed the comparative study for damage detection. Independent component (IC) analysis was used to analyze the transmission and reflection hyperspectral images and to extract the features, the resulting characteristics were used for the secondary IC analysis of the reflected images and the variable selection of the transmittance and reflectance spectroscopy. Finally, the potato injury qualitative recognition model was established based on the reflection images, the reflectance spectral and the transmittance spectral; Further optimization was done for high recognition accuracy of model, and secondary variable selection was carried out for the transmission spectrum by the Sub-window Permutation Analysis(SPA) and the optimal model for damage identification of potato randomly placed was established. The results of experiments show that the accuracy of the identification model based on the reflection image and the reflection spectrum is low, wherein the potato bruise based on the reflection images falls into the lowest recognition accuracy of 43.10% when it is side to the camera; The accuracy of the model for identification based on the transmittance spectroscopy information is the highest, the recognition accuracy with the damage part facing and back to the camera is 100%, and 99.53% when it is side to the camera. The accuracy of the optimal model for identification based on the 3 kinds of transmittance spectroscopy information of randomly placed potato is 97.39%.Then the application of transmission hyperspectral imaging technology could detect potato injury in any orientation, and the research can provide technical support for the online detection of potato quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3366 (2013)
Identification of Lettuce Leaf Nitrogen Level Based on Adaboost and Hyperspectrum
SUN Jun, JIN Xia-ming, MAO Han-ping, WU Xiao-hong, TANG Kai, and ZHANG Xiao-dong
In order to facilitate lettuce fertilization in an economically rational way, an intelligent method to identify lettuce leaf nitrogen levels was studied. Lettuce samples of different nitrogen levels were cultivated in greenhouse with soilless cultivation method. In a particular growth period, the lettuce samples in varIn order to facilitate lettuce fertilization in an economically rational way, an intelligent method to identify lettuce leaf nitrogen levels was studied. Lettuce samples of different nitrogen levels were cultivated in greenhouse with soilless cultivation method. In a particular growth period, the lettuce samples in various nitrogen levels were collected, then the FieldSpec○R3 spectrometer was used to acquire the hyperspectral data of the cultivated lettuce leaves. As there were much noise and redundant information in original hyperspectral data, standard normal variate transformation (SNV) was used to reduce the noise of the original hyperspectral data in this paper, then the principal component waves were extracted by principal component analysis (PCA). While K nearest neighbor (KNN) and support vector machine (SVM) were used for classification studies on the processed hyperspectra data respectively, adaptive boosting (Adaboost) was introduced into the two classifiers as it could improve the classification performance of weak classifiers, then Adaboost-KNN and Adaboost-SVM, the two integrated classification algorithms, were proposed. At last, the four classification algorithms were used for classification and identification of the same test sample data respectively, with the results showing that the classification accuracies of KNN, SVM, Adaboost-KNN and Adaboost-SVM were high up to 74.68%, 87.34%, 100% and 100%, among which the classification accuracies of Adaboost-KNN and Adaboost-SVM proposed in this paper were both good, and the stability of Adaboost-SVM was the best. Therefore, Adaboost-SVM used as a modeling method is suitable for the identification of lettuce leaf nitrogen level based on hyperspectrum, and it can also be used for reference to identify the nutrient elements of other crops in nondestructive testing methods..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3372 (2013)
The Progress in Speciation Analysis of Trace Elements by Atomic Spectrometry
WANG Zeng-huan, WANG Xu-nuo, KE Chang-liang, and LIN Qin
The main purpose of the present work is to review the different non-chromatographic methods for the speciation analysis of trace elements in geological, environmental, biological and medical areas. In this paper, the sample processing methods in speciation analysis were summarized, and the main strategies for non-chromThe main purpose of the present work is to review the different non-chromatographic methods for the speciation analysis of trace elements in geological, environmental, biological and medical areas. In this paper, the sample processing methods in speciation analysis were summarized, and the main strategies for non-chromatographic technique were evaluated. The basic principles of the liquid extractions proposed in the published literatures recently and their advantages and disadvantages were discussed, such as conventional solvent extraction, cloud point extraction, single droplet microextraction, and dispersive liquid-liquid microextraction. Solid phase extraction, as a non-chromatographic technique for speciation analysis, can be used in batch or in flow detection, and especially suitable for the online connection to atomic spectrometric detector. The developments and applications of sorbent materials filled in the columns of solid phase extraction were reviewed. The sorbents include chelating resins, nanometer materials, molecular and ion imprinted materials, and bio-sorbents. Other techniques, e.g. hydride generation technique and coprecipitation, were also reviewed together with their main applications..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3377 (2013)
Segregation Bands Analysis of Steel Sample Using Laser-Induced Breakdown Spectroscopy
ZHANG Yong, JIA Yun-hai, CHEN Ji-wen, SHEN Xue-jing, ZHAO Lei, LI Dong-ling, LIU Ying, YANG Chun, HANG Peng-cheng, and WANG Hai-zhou
In the present paper, under optimum experimental condition, two middle-low alloy slab and homogeneous samples were analyzed under the condition of spatial resolution about 100 μm by scanning mode. Element 2D intensity distribution can be converted into 2D concentration distribution via establishing calibration curve. TIn the present paper, under optimum experimental condition, two middle-low alloy slab and homogeneous samples were analyzed under the condition of spatial resolution about 100 μm by scanning mode. Element 2D intensity distribution can be converted into 2D concentration distribution via establishing calibration curve. The results showed that there is a central segregation for C, Si, Mn, P, S and Cu for 86# slab sample, and C, Si, P and Ti for 174# slab sample, the width of segregation band was estimated, and it agrees well with metallographic analysis. Homogeneous sample was analyzed by scanning mode, the result showed that C, Si, Mn, P, S and so on are well distributed, and there is no segregation band existing. 2D distribution of element intensity or concentration can be used to indirectly reflect sample’s homogeneity. Compared with traditional metallographic analysis, LIBS can not only show central segregation bands position and width, but also provide 2D concentration distribution for C, Si, Mn, P, S etc in detail. This method can be used to characterize segregation band position and its width rapidly, and provide theoretical guidance for improving metallurgical process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3383 (2013)
Laser-Induced Breakdown Spectroscopy System for Elements Analysis in High-Temperature and Vacuum Environment
PAN Cong-yuan, DU Xue-wei, AN Ning, HAN Zhen-yu, WANG Sheng-bo, WEI Wei, and WANG Qiu-ping
Laser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high tLaser-induced breakdown spectroscopy (LIBS) is one of the most promising technologies to be applied to metallurgical composition online monitoring in these days. In order to study the spectral characters of LIBS spectrum and to investigate the quantitative analysis method of material composition under vacuum and high temperature environment, a LIBS measurement system was designed and set up which can be used for conducting experiments with high-temperature or molten samples in different vacuum environment. The system co nsists of a Q-switched Nd∶YAG laser used as the light source, lens with different focus lengths used for laser focusing and spectrum signal collecting, a spectrometer used for detecting the signal of LIBS spectrums, and a vacuum system for holding and heating the samples while supplying a vacuum environment. The vacuum was achieved and maintained by a vacuum pump and an electric induction furnace was used for heating the system. The induction coil was integrated to the vacuum system by attaching to a ceramic sealing flange. The system was installed and testified, and the results indicate that the vacuum of the system can reach 1×10－4Pa without heating, while the heating temperature could be about 1 600 ℃, the system can be used for melting metal samples such as steel and aluminum and get the LIBS spectrum of the samples at the same time. Utilizing this system, LIBS experiments were conducted using standard steel samples under different vacuum or high-temperature conditions. Results of comparison between LIBS spectrums of solid steel samples under different vacuum were achieved, and so are the spectrums of molten and solid steel samples under vacuum environment. Through data processing and theoretical analyzing of these spectrums, the initial results of those experiments are in good agreement with the results that are presently reported, which indicates that the whole system functions well and is available for molten metal LIBS experiment under vacuum environment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3388 (2013)
Delivery of Megawatts High Energy Laser Pulse with Large Core Diameter Silica Fiber and Its Application in Dual-Wavelength Laser-Ablation Laser-Induced Breakdown Spectroscopy
ZHOU Qi, PENG Fei-fei, LI Run-hua, CHEN Yu-qi, and YANG Xue-jiao
To resolve the contradiction between spatial resolution and analysis sensitivity in single pulse laser-induced breakdown spectroscopy (LIBS), a study on dual-wavelength laser-ablation laser-induced breakdown spectroscopy (LA-LIBS) was carried out by using one Nd∶YAG laser which was capable of two laser beam outputs witTo resolve the contradiction between spatial resolution and analysis sensitivity in single pulse laser-induced breakdown spectroscopy (LIBS), a study on dual-wavelength laser-ablation laser-induced breakdown spectroscopy (LA-LIBS) was carried out by using one Nd∶YAG laser which was capable of two laser beam outputs with different wavelengths, where, the second harmonic output, 532 nm laser beam, was used as laser-ablation source, and the fundamental output, 1 064 nm laser beam, was delivered with a large core diameter silica fiber to realize nanoseconds time-delay and then used to breakdown the ablated samples. Two laser beams were orthogonally arranged to realize element analysis with high spatial resolution and high sensitivity. Some key techniques on the coupling of 1 064 nm laser beam into fiber, the collimation of laser at the fiber end and re-focusing of the laser beam were studied. The energy delivery capabilities of four fibers of different types were studied and the maximum values were determined experimentally. A Q-switched laser pulse with 15 mJ pulse energy was successfully delivered by selecting a 50 meter long silica fiber with 800 μm core diameter and 0.39 numerical aperture. And 250 ns time-delay was realized. A copper alloy was analyzed by spectra with current established LA-LIBS system and the possibility of realizing dual-wavelength LA-LIBS analysis based on one Nd∶YAG laser was demonstrated experimentally. In this technique, only one Nd∶YAG laser was required to carry out spectral analysis. It has a few advantages, such as simple equipment structure, and being convenient to miniaturize the whole system etc. This dual-wavelength LA-LIBS technique was suitable for in-situ elements microanalysis for different samples with both high spatial resolution and high sensitivity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3392 (2013)
Application of ICP-MS in Assessing the Pollution of Seldom Monitored Trace Elements in City Roadside Dusts
YIN Shu-hua, GAO Bo, LI Qiang, ZHOU Huai-dong, WANG Jian-kang, and HUANG Yong
Seldom monitored trace element concentrations in road dusts colleted from Shihezi City were studied. A total of 32 sampling stations were selected. The concentration of 10 seldom monitored trace elements (B, Be, Bi, Co, Ga, Li, Sb, Sn, Tl, V) were determined. Their pollution degree and source identification were analyzSeldom monitored trace element concentrations in road dusts colleted from Shihezi City were studied. A total of 32 sampling stations were selected. The concentration of 10 seldom monitored trace elements (B, Be, Bi, Co, Ga, Li, Sb, Sn, Tl, V) were determined. Their pollution degree and source identification were analyzed by using Geoaccumulation Index, correlation coefficient and principal factor analysis. The results indicated that the mean concentrations of Li, Be, B, V, Co, Ga, Sn, Sb, Tl and Bi were 24.91, 1.68, 41.11, 72.66, 13.58, 36.26, 3.64, 3.37, 0.42 and 0.52 mg·kg-1, respectively. The mean concentrations of Li, Tl, Co, Be, B, and V were lower than or similar to the soil background values of Xinjiang province. However, the mean concentrations of Ga, Sn, Sb and Bi were higher than the background values of Xijiang province and world soil. The results of Geoaccumulation Index indicated that the pollution degrees of Li, Be, B, V, Co, Ga and Tl were zero, and belonged to the category of non-pollution. However the pollution of Sb, Bi and Sn were considerably serious, and their pollution grades were 2, 1 and 1 respectively. The source of SMTEs in road dusts of Shihezi City was identified by multivariate statistics (principal component analysis and correlation analysis). The results showed that Sb, Co, Tl and Bi mainly originated from human activities, Li, Be, B, V represented natural sources, while Sn and Ga have the mixed sources of nature and human activities..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3396 (2013)
Study on High Pressure Sample Preparation Method for Pressed Powder Pellet and Its Application in X-Ray Fluorescence Spectrum Analysis
ZHANG Qin, YU Zhao-shui, LI Xiao-li, and LI Guo-hui
Using the independently designed high pressure sample preparation mold and high pressure sample preparation technology (patent number: 201310125772.5), studies on the high pressure pressed various geological samples such as rocks, soils and stream sediments were first described in the present paper. It is the first expUsing the independently designed high pressure sample preparation mold and high pressure sample preparation technology (patent number: 201310125772.5), studies on the high pressure pressed various geological samples such as rocks, soils and stream sediments were first described in the present paper. It is the first experiment conducted in this field with significant achievements obtained. Without any binder, various types of geological powder samples can be pelleted well using 1600KN high pressure method. Such pellet has the characteristics of dense, flat, smooth and shiny surface, no cracks, no delamination, and no powder dropping. The study provides a new and contamination-free approach to sample preparation of X-ray fluorescence spectrum analysis. The comparison study conducted between the same samples pelleted under the low pressure (400 kN) and high pressure (1 600 kN) showed that using the high pressure the element peak to background ratios, and sensitivities are significantly improved, the detection limits are lowed, and the accuracies, the precisions and sample preparation repeatability are greatly improved. The Si FWHM became wider for the high pressure (1 600 kN) pellet than the same sample pelleted under the lower pressure (400 kN). The further SEM observation revealed that variation of Si spectrum shape may be caused by that the silica crystal lattices are destroyed and the particle size becomes smaller by using the high pressure pelleting techniques. So the particle size and mineral effects are also effectively reduced and the precisions and accuracies of the analytical method are improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3402 (2013)
Determination of Film Thickness, Component and Content Based on Glass Surface by Using XRF Spectrometry
MEI Yan, MA Mi-xia, and NIE Zuo-ren
Film thickness, component and content based on glass surface were determined by using XRF technic, measure condition and instrument work condition in every layer were set and adjusted for the best measure effect for every element. Background fundamental parameter (BG-FP) method was built up. Measure results with this mFilm thickness, component and content based on glass surface were determined by using XRF technic, measure condition and instrument work condition in every layer were set and adjusted for the best measure effect for every element. Background fundamental parameter (BG-FP) method was built up. Measure results with this method were consistent with the actual preparation course and the method could fit to production application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3408 (2013)
Searching for Dwarf Nova Candidates with Automatic Methods in Massive Spectra
WANG Wen-yu, WANG Xin-jun, and PAN Jing-chang
In the present paper, an automatic and efficient method for searching for dwarf nova candidates is presented. The methods PCA (principal component analysis) and SVM (support vector machine) are applied in the newly released SDSS-DR9 spectra. The final dimensions of the feature space are determined by the identificationIn the present paper, an automatic and efficient method for searching for dwarf nova candidates is presented. The methods PCA (principal component analysis) and SVM (support vector machine) are applied in the newly released SDSS-DR9 spectra. The final dimensions of the feature space are determined by the identification accuracy of training samples with different dimensions constrained by SVM. The massive spectra are dimension reduced by PCA at first and classified by the best SVM classifier. The final less number of candidates can be identified manually. A total number of 276 dwarf nova candidates are selected by the method and 6 of them are new discoveries which prove that our approach to finding special celestial bodies in massive spectra data is feasible. The new discoveries of this paper are added in the current dwarf nova template library which can contribute to constructing a more accurate feature space. The method proposed in this paper can also be used for special objects searching in other sky survey telescopes like Guoshoujing (Large Sky Area Multi-Object Fiber Spectroscopic Telescope -LAMOST) telescope..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3411 (2013)
Nonlalocalized Interference in Multiple-Beam Interferometer
CHEN Hai-liang, LI Shu-guang, WANG Suo-ming, SUN Xin, LI Xing-yuan, and ZHU Er-kuang
The authors studied the nonlocalized interference in multiple-beam interferometer. The light intensity distribution function was obtained. The result shows that the function in the circle center has the same form with localized interference. Numerical simulation method was used to analyse the light intensity distributiThe authors studied the nonlocalized interference in multiple-beam interferometer. The light intensity distribution function was obtained. The result shows that the function in the circle center has the same form with localized interference. Numerical simulation method was used to analyse the light intensity distribution function. As the reflection coefficient increases, the stripe becomes sharp, Resolution ratio was improved, while the noise occured around the lower interference index. The noise becomes obviously as the reflection coefficient increases. While changing the receiving screen distance, the simulation result shows that linear relationship exists between inteference index and cosine value of interference stripe dip angle. The mirror spacing can be obtained through the straight line slope. With changing the mirror spacing, the numerical simulation result shows that linear relationship exists between interference index and stripe radii square. The straight slope shows a linear relationship with the mirror spacing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3415 (2013)
Comparative Study on Software Demodulation for Continuous Wave and Quasi-Continuous Wave Wavelength Modulation Spectroscopy
SHAO Xin, LIU Fu-gui, and CHEN Wen-liang
According to the modulation signal applied on laser diodes, wavelength modulation spectroscopy (WMS) can be divided into continuous wave (CW) WMS and quasi-continuous wave (QCW) WMS. In order to deeply compare CW-WMS and QCW-WMS, we used a specific software-realized lock-in amplifier for continuous and quasi-continuousAccording to the modulation signal applied on laser diodes, wavelength modulation spectroscopy (WMS) can be divided into continuous wave (CW) WMS and quasi-continuous wave (QCW) WMS. In order to deeply compare CW-WMS and QCW-WMS, we used a specific software-realized lock-in amplifier for continuous and quasi-continuous modulation signal demodulation. The invalid signal in quasi-continuous modulation spectrum was filtered off, and then the effective detection signal was demodulated to obtain the second harmonic signal (WMS-2f). It was compared with the 2f signal demodulated continuous laser modulation spectrum with software. The results show that while the same system parameters are set, the signal-to-noise of the quasi-continuous modulation spectrum is 5% higher than the continuous modulation spectrum with software demodulation measurements, and the detection limit is 11.3% lower. And without the invalid signal in quasi-continuous modulation spectrum, the standard WMS-2f signal can be demodulated, which has potential to be used for the investigation of gas absorption profile. This work has provided accurate reference for selections of the laser modulation spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3419 (2013)
The Experiment Research on Solution Refractive Index Sensor Based on Tilted Fiber Bragg Grating
JIANG Qi, LV Dan-dan, YU Ming-hao, KANG Li-min, and OUYANG Jun
The present paper analyzes the sensor’s basic principle of the bare tilted fiber Bragg grating (TFBG) and surface plasmon resonance sensor (SPR) that deposited nanoscale gold-coating on the surface of the cladding. We simulated the transmission spectrums and some order cladding mode of TFBG in different concentration sThe present paper analyzes the sensor’s basic principle of the bare tilted fiber Bragg grating (TFBG) and surface plasmon resonance sensor (SPR) that deposited nanoscale gold-coating on the surface of the cladding. We simulated the transmission spectrums and some order cladding mode of TFBG in different concentration solutions by Integration and optical fiber grating software OptiGrating. So by the graphic observation and data analysis, a preliminary conclusion was got that in a certain sensing scope, the cladding modes of TFBG shift slightly to right with the increasing the solution refractive index(SRI), and the relation between resonance peak caused by the coupling of core mode and a certain cladding mode and the SRI was linear. Then the 45 nm thick gold coating was deposited on the surface of the TFBG cladding in a small-scale sputtering chamber KYKY SBC-12, and thermal field scanning electron microscopy presents that the effect of gold-coating was satisfactory to a certain extent in terms of microscopic level . The refractive index(RI) sensing experiments of different concentration solutions of NaCl, MgCl2, CaCl2 were carried out using bare and gold deposited TFBG. The RI sensing characteristics of both bare and gold deposited TFBGs respectively were studied by experiments. Meanwhile, it proved the conclusion that the cladding modes of TFBG drifted to right gradually when the SRI was increasing and the relations between resonance peak caused by the coupling of core mode and a certain cladding mode and the SRI were linear. And by quantitative analysis, we know that SPR sensor with the deposited namoscale gold layer on the surface of cladding enhanced the RI sensitivity dramatically by 2 to 500 nm·RIU-1 which is 200 to 300 times larger than that of the bare tilted fiber Bragg grating approximately. The degrees of linear fittings of resonance peak caused by the coupling of core mode and a certain cladding mode and SRI of bare and gold-coating deposited SPR sensor are very good and both of them reach up to more than 0.99..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3425 (2013)
Design of Airborne Dual Channel Ultraviolet-Visible Imaging Spectrometer with Large Field of View, Wide Spectrum, and High Resolution
HAO Ai-hua, HU Bing-liang, BAI Jia-guang, LI Li-bo, YU Tao, and LI Si-yuan
The ultraviolet-visible (UV-Vis 200～500 nm) imaging spectrometer is an important part of space remote sensing. Based on special requirements and practical application of the airborne UV-VIS spectrometer, a kind of scanning imaging spectrometer using area array CCD is proposed, which can meet the application requirementThe ultraviolet-visible (UV-Vis 200～500 nm) imaging spectrometer is an important part of space remote sensing. Based on special requirements and practical application of the airborne UV-VIS spectrometer, a kind of scanning imaging spectrometer using area array CCD is proposed, which can meet the application requirements of large field of view, wide spectrum and high resolution. It overcomes low spatial resolution of traditional line array CCD scanning imaging spectrometer, and limited field of view of the pushbroom imaging spectrometer. In addition, dual channel was designed to reduce stray light. 400～500 nm band includes two order spectrum for 200～250 nm band, and variation of radiance from earth between the shorter wavelength (<290 nm) and the longer wavelength (>310 nm) is above three orders of magnitude. In the structure design of the system, the imaging spectrometer is composed of a two-mirror concentric telescope and two Czerny-Turner plane grating imaging spectrometers. The whole system doesn’t use any additional optical elements in addition to spherical mirrors. The whole system has the advantage of simple structure, excellent performance, and very good feasibility. The modulation transfer function value of full spectrum and full field of view is above 0.6..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3432 (2013)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1 (2013)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 3437 (2013)
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