Journals >Spectroscopy and Spectral Analysis
Contents
2016
Volume: 36 Issue 8
65 Article(s)
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Research Article
Understanding the Effected Efficiencies of Polymer Solar Cells Employing Different Fullerene Multiadducts as Acceptors
HUANG Di, XU Zheng, ZHAO Su-ling, ZHAO Jiao, LI Yang, and ZHAO Ling
The application of fullerenes with two or more adducts as acceptors has greatly enhanced the performance of bulk-heterojunction solar cells with poly (3-hexylthiophene) (P3HT) as the donor. The enhancement is caused by a substantial increase in the open-circuit voltage due to a rise in the fullerene lowest unoccupied mThe application of fullerenes with two or more adducts as acceptors has greatly enhanced the performance of bulk-heterojunction solar cells with poly (3-hexylthiophene) (P3HT) as the donor. The enhancement is caused by a substantial increase in the open-circuit voltage due to a rise in the fullerene lowest unoccupied molecular orbital (LUMO) level when going from monoadducts to multiadducts. While the increase in the open-circuit voltage is obtained with many different polymers, most polymers other than P3HT show a substantially reduced photocurrent when blended with fullerene multi-adducts such as bis adduct of Phenyl-C61 -butyric acid methyl ester (bis-PCBM) or the indene-C60 bis-adduct (ICBA). Here we investigate the reasons for this change in performance of polymer solar cells(PSCs) based on ［6,6］-phenyl C70-butyric acid methyl ester (PC70BM), ICBA and bis-PC70BM as the acceptors and poly［［4,8-bis［(2-ethylhexyl)oxy]benzo［1,2-b:4,5-b’］dithiophene-2,6-diyl］［3-fluoro-2-［(2-ethylhexyl)carbonyl］thieno［3,4-b]thiophenediyl］］（PTB7）as the donor. The cell configuration is ITO/PEDOT: PSS/active layer /LiF/Al .The PSCs with PC70BM, ICBA and bis-PC70BM show PCEs of 7.29%, 4.92% and 3.33%, respectively. The change of performance of the PSCs could be mainly attributed to the different excition generation and charge collection of PSCs employing different fullerene multi-adducts as acceptors..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2363 (2016)
Analysis of Microfiber Knot Resonator Spectrum for Seawater Temperature
YANG Hong-juan, LIAO Yi-peng, WANG Shan-shan, WANG Xin, and WANG Jing
As a sensing device, microfiber knot resonator (MKR) has been widely used in sensing field due to its advantages of high sensitivity and fast response. It is important to analyze the spectrum of MKR for detecting environmental parameters in that the spectrum can reflect the change of ambient environment. In this paper,As a sensing device, microfiber knot resonator (MKR) has been widely used in sensing field due to its advantages of high sensitivity and fast response. It is important to analyze the spectrum of MKR for detecting environmental parameters in that the spectrum can reflect the change of ambient environment. In this paper, the relationship between spectrum of MKR and seawater temperature has been studied theoretically and experimentally. Firstly, the dependences of the propagation constants of fundamental mode (HE11) on the fiber diameter and the probing wavelength are studied theoretically in this paper, including two orthogonal polarization states of fundamental mode. The calculated results show that the propagation constant increases with the increasing fiber diameter and the decreasing probing wavelength. Simultaneously, the dependence of propagation constant of fundamental mode on seawater temperature is studied. The results show that the larger propagation constant corresponds to the higher seawater temperature, which indicates that the seawater temperature affect the mode propagation constant. Thus, the seawater temperature can be obtained by detecting the resonant spectrum. Secondly, the experimental system for seawater temperature sensing is set up, with which the resonant spectrum of MKR for seawater temperature sensing are obtained. The experimental results show that two sets of resonant peak exist on the spectrum, which are corresponding to TE and TM modes of fundamental mode. The sensing sensitivities of the two polarization modes are 5.54 pm/°C and 5.24pm/°C, respectively. Finally, the reason for resonant spectrum of the two polarization states is discussed, which is that the separation of the two modes resulting from the twisted coupler of the knot zone, and the resonant intensity of the two polarization modes is analyzed. The resonant intensities of the two modes are different and one increases while the other one decreases with the increasing probing wavelength. It is determined by the coupling coefficients and attenuations of the two coupled states, which are affected by the probing wavelength. The experimental and theoretical results agree well..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2368 (2016)
Study on the High Speed and Precision Gaussian Function Fitting Algorithm for Nuclear Single Spectral Peak
MA Ying-jie, ZHOU Jing, HONG Xu, ZHOU Jian-bin, WANG Min, and WAN Wen-jie
In nuclear spectrum, Gaussian function least square fitting is a commonly used method. Usually the method has high precision, but it is very much sensitive to noise, which causes that the residual vector is larger near the peak in the Gaussian function. To solve the problem, Gaussian function least square fitting was dIn nuclear spectrum, Gaussian function least square fitting is a commonly used method. Usually the method has high precision, but it is very much sensitive to noise, which causes that the residual vector is larger near the peak in the Gaussian function. To solve the problem, Gaussian function least square fitting was deduced particularly, and the causes are analyzed. As a result, Gaussian function weighted least square fitting is proposed, i.e., a weight factor, which had an opposite tendency to the data weight reduction tendency after taking logarithm, or it had the same tendency to the origin data. This was introduced based on Gaussian function least square fitting to reduce noise sensitivity. In the process of solving Gaussian parameter, to improve the real-time performance, the solution process of inverse matrix was transferred to the solution process of simple equations because the computation of inverse matrix was time consuming. Gaussian function parameter, amplitude, center value and variance, were given with the fast calculation formulas. By applying these two methods to the practical fitting of 55Fe characteristic X-ray single spectrum peak, respectively, the results show that Gaussian function weighted least square fitting is more satisfactory. It indicates the proposed method can decrease the noise sensitivity and reduce the residual vector near the peak; in addition, the fitting precision is also improved. What's more, the real-time performance is improved by applying fast calculation formulas, which makes it possible to apply the proposed method to portable equipment efficiently..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2373 (2016)
Precipitable Water Vapor Retrieval with MODIS Near Infrared Data
ZHANG Tian-long, WEI Jing, GAN Jing-min, ZHU Qian-qian, and YANG Dong-xu
Precipitable water vapor (PWV) shows great significance in remote sensing quantitative application and ecological research. Aiming at solving the problems of traditional methods, an Improved Continuum Interpolated Band Ratio (ICIBR) algorithm was proposed based on the ratios of apparent reflectance of multi-channels inPrecipitable water vapor (PWV) shows great significance in remote sensing quantitative application and ecological research. Aiming at solving the problems of traditional methods, an Improved Continuum Interpolated Band Ratio (ICIBR) algorithm was proposed based on the ratios of apparent reflectance of multi-channels in this paper. The ICIBR algorithm considers the absorption characteristics of water vapor absorption in three MODIS near infrared channels (Bands 17, 18 and 19) and the relationship between the PWV and the ICIBRs of above three channels were simulated by using the MORTRAN model. Then the PWV retrieval model for MODIS data was constructed. Texas, Oklahoma region, a typical arid/semi-arid areas, located in North South America were selected as the study area and four different MODIS 1B data were obtained to perform PWV retrieval experiments using the ICIBR algorithm. Last, the corresponding GPS PWV ground observation data provided by SuomiNet and the MODIS PWV product (MOD05) were obtained to verify the experiment results. Evaluation and comparison results showed that the PWV retrievals showed a higher consistency (r=0.967) with the GPS ground measured PWV data with smaller RMSE~0.276 cm and a total of 71.08% of observation points falling within PWV Expected Errors (EE~±0.05+0.15PWVgps). Moreover, the ICIBR algorithm showed an obviously great improvement in PWV estimation, which can effectively reduce 61% overestimation of PWV retrievals than MOD05 PWV products. This new algorithm is more simple and practical with an overall more reliable retrieval accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2378 (2016)
Investigation of Atmospheric Formaldehyde and Glyoxal Based on Differential Optical Absorption Spectroscopy
SHEN Shi-liang, WANG Shan-shan, and ZHOU Bin
This paper proposes a method to monitor atmospheric HCHO and CHOCHO with high temporal resolution based on differential optical absorption spectroscopy (DOAS) in Shanghai urban area. Based on the characteristic absorbing structure of HCHO and CHOCHO, different fitting intervals were chosen for spectral analysis in ordeThis paper proposes a method to monitor atmospheric HCHO and CHOCHO with high temporal resolution based on differential optical absorption spectroscopy (DOAS) in Shanghai urban area. Based on the characteristic absorbing structure of HCHO and CHOCHO, different fitting intervals were chosen for spectral analysis in order to avoid the absorption of interfering gases and reduce the residuals of spectral analysis. The resulting optical thickness of the target gas is used to obtain HCHO and CHOCHO concentrations, which were averaged at (4.0±1.6) and (3.4±1.2) μg·m-3 in October 2013, respectively. The averaged concentrations of HCHO in workdays were higher than those in holidays due to the impacts of its anthropogenic emission sources, while no obvious differences of averaged CHOCHO concentrations between workdays and holidays were observed. Diurnal patterns of HCHO and CHOCHO were alike. In the early morning, both the HCHO and CHOCHO concentrations peaked at 06:00—07:00, and then decreased rapidly to the minimum around 09:00. Afterwards, the concentrations increased continuously until sunset and kept in a relatively stable level in the evening. To explore the possible emission source and formation mechanism of atmospheric HCHO, four typical periods, i.e. steady-state stage at night, morning rush hours, photochemical reaction stage and evening rush hours, were classified for source apportionment.NO2 is regarded as the indicator for primary source of ambient HCHO.As the intermediate products of photochemical reactions, HCHO has a similar formation mechanism in common with CHOCHO. Therefore, it is reasonable to use CHOCHO as an indicator for secondary source of ambient HCHO. The linear regression analysis showed a good agreement between modeled and observed HCHO concentrations, the correlation coefficients R2 ranged from 0.60 to 0.81. Secondary sources of HCHO were estimated to contribute to one third of ambient HCHO concentrations in Shanghai urban area..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2384 (2016)
Research on Quantitative Method for the Determination of Carbon Isotopic Composition of CO2 with Micro-Laser Raman Spectroscopy
LI Jia-jia, LI Rong-xi, DONG Hui, WANG Zhi-hai, ZHAO Bang-sheng, and WANG Ning
In this study, a series of 12CO2/N2 and 13CO2/N2 binary mixtures with various molar fraction ratios were synthesized. It was found that the Raman peak area ratios were proportional to molar fraction ratios. The linearity of the working curves was very good. Moreover, the slopes of working curves were regarded as Raman In this study, a series of 12CO2/N2 and 13CO2/N2 binary mixtures with various molar fraction ratios were synthesized. It was found that the Raman peak area ratios were proportional to molar fraction ratios. The linearity of the working curves was very good. Moreover, the slopes of working curves were regarded as Raman quantification factor (F12CO2 and F13CO2). The natural fluids only containing 12CO2 and N2 composition in the gas phase have been applied to estimate their molar fraction ratios when F12CO2 is 1.163 49. As F13CO2 and F12CO2 are equal to 1.610 86 and 1.163 49, their ratio (F13CO2/F12CO2) is 1.384 5. Based on the study of principles and feasibility of the method of laser Raman spectroscopy, the molar fraction ratio C12/C13 would be calculated using the product of A12CO2/A13CO2 (the ratio of Raman peak area) and F13CO2/F12CO2. In addition, man-made inclusions with known molar fraction ratios (C12/C13) were presented to testify the validity and precision of the method. The possibility of quantifying carbon isotopic composition of CO2 with Micro-Laser Raman Spectroscopy is demonstrated..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2391 (2016)
Luminescence Characteristics of Scintillator Y2SiO5∶Ce
WANG Wen-jing, DING Xi-feng, SUN Xin, ZHU Er-kuang, LI Xing-yuan, ZHANG Hong-mei, GUO De-feng, and CHEN Hai-liang
Cerium doped Y2SiO5 (YSO) is an important scintillator material due to its high density, non-hygroscopic, excellent light output and fast decay time nature. in the paper, Y2SiO5∶Ce3+0.2%(YSO∶Ce) was grown with high-temperature solid-phase method. The time-resolved excitation and emission spectra and fluorescent decay cCerium doped Y2SiO5 (YSO) is an important scintillator material due to its high density, non-hygroscopic, excellent light output and fast decay time nature. in the paper, Y2SiO5∶Ce3+0.2%(YSO∶Ce) was grown with high-temperature solid-phase method. The time-resolved excitation and emission spectra and fluorescent decay curves at low temperature and room temperature (RT) were measured and discussed. There were two types of luminescence, one was the crystal defect emission, the center at 320 nm; the other one was doped Ce3+ ions 5d→4f emission, the center at 440 nm. Only when the excitation energy (Ex) was greater than the band gap width (Eg), the crystal defect emission can be observed corresponding to slow process, and the emission intensity was higher at low temperature. The crystals defect emission was hardly observed in the time-resolved emission spectra when the temperature rose to room temperature because of temperature quenching. Regions from 60~300 nm corresponding to emission due to 5d→4f transitions in the activator Ce3+ ions peaks at 440 nm, a plurality of excitation peaks were observed. Among them, the excitation with energy less than 6.1 eV(Ex
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2399 (2016)
Study on the Synergistic Antioxidant Mechanism of Chlorogenic Acids (CQAs) with Electrochemical and Spectroscopy Property
YANG Kai-zhou, ZHAI Xiao-na, WANG Jia-liang, CHAI Zhi, REN Fa-zheng, and LENG Xiao-jing
The synergistic antioxidant mechanism of chlorogenic acids (CQAs) was studied in this paper through cyclic voltammograms (CV), oil-water partition coefficient (P), FT-IR, XRD and circular dichroism (CD). The antioxidant capability of CQAs isomers and their mixture was determined by using ABTS free radical quenching abiThe synergistic antioxidant mechanism of chlorogenic acids (CQAs) was studied in this paper through cyclic voltammograms (CV), oil-water partition coefficient (P), FT-IR, XRD and circular dichroism (CD). The antioxidant capability of CQAs isomers and their mixture was determined by using ABTS free radical quenching ability assay. The results showed that the bigger the antioxidant activity disparity between the CQAs molecules was, the higher the content of high antioxidant activity CQAs was, the better the synergistic effect of the CQAs combination mixture became; The oxidation potential (Epa) of CQAs combination mixture kept constant in the synergistic experiments, which indicted the oxidative coupling interaction don't exist between the CQAs; The charge transferred (Q) and antioxidant activity exhibited high correlation (0.92); the practical Q was higher than the theoretical Q in the synergistic process and this confirmed that the CQAs (dicaffeoylquinic acids) regeneration of high antioxidant activity happened; the CQAs mixture with the absolute difference value of oil-water partition coefficient of 0.13 gave the good interface effect and high synergistic degree; the interaction and the regular arrangement between the CQAs combination were not discovered through FT-IR, XRD and CD. Therefore, the regeneration mechanism of CQAs molecules and the interface effect of reaction system were the main cause of the phenomenon of the synergistic antioxidant of CQAs..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2405 (2016)
Estimating Surface Broadband Emissivity of the Taklimakan Desert with FTIR and MODIS Data
LI Huo-qing, WU Xin-ping, Ali Mamtimin, HUO Wen, YANG Xing-hua, YANG Fan, HE Qing, and LIU Yong-qiang
Surface broadband emissivity in the thermal infrared region is an important parameteras for the studies of the surface energy balance. This paper analyzed and offered an equation to estimate the surface broadband emissivity for the spectral domains 8～14 μm against the MODIS data, and then, the distribution characteristSurface broadband emissivity in the thermal infrared region is an important parameteras for the studies of the surface energy balance. This paper analyzed and offered an equation to estimate the surface broadband emissivity for the spectral domains 8～14 μm against the MODIS data, and then, the distribution characteristic of surface emissivity for Taklimakan Desert was obtained with this equation. Firstly, along two highways crossing the Taklimakan Desert, twenty sample sites were selected and their spectral of broadband emissivity were observed with Fourier Transform Infrared spectrometer (FTIR). Secondly, using the Moderate Resolution Imaging Spectrometer (MODIS) land surface temperature and emissivity product MOD11A1 and MOD11C1, derived emissivities in three thermal infrared channels 29 (8.4～8.7 μm), 31 (10.78～11.28 μm) and 32 (11.77～12.27 μm) and MODIS surface reflectance products MOD09A1, derived reflectance in near-infrared channel 7 (2.105～2.155 μm), developing an empirical regression equation to convert these spectral emissivities and reflectance to a broadband emissivity. The FTIR data were used to determine the coefficients of the regression equation, another part of FTIR data were used to investigate the accuracy of equation. It was found that the equation consist of MODIS channels 29, 31 and 32 has more accuracy; furthermore, the accuracy is improved when channel 7 data was added in the regression equation. The root mean square error (RMSE) and Bias were 0.004 5 and 0.000 1, respectively. Comparing to other six equations originated from literatures, which also estimate the surface broadband emissivity from narrowband emissivities. The RMSE and Bias of our equation are lower one order and two orders of magnitude than other six equations, respectively. Lastly, our equation is applied in the Taklimakan Desert area to build a distribution image of emissivity based on MODIS data. It demonstrates that the emissivity of Taklimakan Desert is in the range of 0.880～0.910 over the central regions, the averaged value is 0.906; The emissivity is in the range of 0.910～0.940 where the areas covered by spare vegetation; The emissivity is in range of 0.950～0.980 where the regions near to the oasis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2414 (2016)
Study on the Genetic Relationship of Panax Notoginseng and Its Wild Relatives Based on Fourier Translation Infrared Spectroscopy
LI Yun, WANG Yuan-zhong, YANG Wei-ze, YANG Shao-bing, ZHANG Jin-yu, and XU Fu-rong
Wild relatives play a very important role in enriching germplasm resources and improving the quality and yield of cultivated species. In this paper, the genetic relationship between Panax notoginseng and its wild relatives has been investigated by using Fourier transform infrared (FTIR) spectroscopy in order to provideWild relatives play a very important role in enriching germplasm resources and improving the quality and yield of cultivated species. In this paper, the genetic relationship between Panax notoginseng and its wild relatives has been investigated by using Fourier transform infrared (FTIR) spectroscopy in order to provide theoretical bases in the variety improvement of P. notoginseng as well as the development and utilization of germplasm resources. The FTIR spectra of P. notoginseng and its wild relatives (P. japonicus var. major, P. stipuleanatus, P. vietnamensis, P. japonicus var. bipinnatifidus) as well as Panax notoginsenosides were collected. The original infrared spectra of P. notoginseng and its wild relatives were pretreated by automatic baseline correction, smoothing, ordinate normalization and second derivative. The genetic relationship between P. notoginseng and its wild relatives has been studied together with the aid of principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and hierarchical cluster analysis (HCA). By comparing the infrared spectra of P. notoginseng with that of panax notoginsenosides, some common peaks such as 3 400, 2 930, 1 635, 1 385, 1 075 and 927 cm-1 has been found. It showed that the peak heights of P. notoginseng samples may relate with the content of panax notoginsenosides. The original infrared spectra of P. notoginseng are similar to its wild relatives and the absorption peaks of the functional groups of C—H, CO, O—H, C—N and C—O were presented. There were some differences in the fingerprint region (1 800～500 cm-1) of the second derivative spectra of these five species samples. The characteristic absorption peaks such as 1 385 and 784 cm-1 has an obviously differentiation. Then the fingerprint region of second derivative spectra is subjected to be analyzed by PCA and PLS-DA. By comparing the 3D score plots of these two methods, the classification result of PLS-DA is significantly better than PCA. In addition, the result of HCA which based on the six principal components of PLS-DA has shown that P. japonicus var. major and P. vienamensis have close relationship with P. notoginseng while P. stipuleanatus and P. japonicus var. bipinnatifidus are far from P. notoginseng. The use of Fourier transform infrared spectroscopy combined with chemometrics methods could effectively investigate the genetic relationship between P. notoginseng and its wild relatives. Furthermore, it could provide reference for the research of medicinal plants..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2420 (2016)
Research and Implementation of Wood Species Recognition System with Wood Near Infrared Spectral Reflection Features
DOU Gang, CHEN Guang-sheng, and ZHAO Peng
This paper proposes a novel wood species recognition scheme based on the spectral reflection features of wood surface, aiming to address the following three issues in terms of the noise filtering, feature selection and radian’s optimal design . First, noises occur in some bands of wood spectral reflection curve so thatThis paper proposes a novel wood species recognition scheme based on the spectral reflection features of wood surface, aiming to address the following three issues in terms of the noise filtering, feature selection and radian’s optimal design . First, noises occur in some bands of wood spectral reflection curve so that these noisy bands should be deleted. Second, the wood spectral band is 350~2 500 nm, which is a 2 150D vector with a spectral sampling interval of 1 nm. Therefore, both noise filtering and feature selection should be performed to wood spectral data. In this paper, to simultaneously and efficiently solve the two problems of feature selection and noise filtering, both a feature selection procedure and a noise filtering procedure are performed by solving the eigenvalues of dispersion matrix. This scheme is novel and produces a good outcome. Third, to make the spectral reflection curves picked up by the spectral instrument have the best pattern recognition information; an optimal design is performed for the indoor radian's mounting height. The genetic algorithm is used to solve the optimal radian's height so that the spectral reflection curves have the best classification information for wood species. Therefore, the optimal design scheme for the radian's mounting height can improve the pattern classification accuracy of the wood species to some extents, which is novel with excellent executive feasibility. Many experiments made with our developed software system on the five ordinary wood species in northeast region of China (i.e., including Betula platyphylla, Populus davidiana, Pinus Sylvestris, Picea jezoensis, Larix gmelinii) are performed for approximately 105 times. It indicates that the overall recognition rate reaches to a good recognition accuracy of 95% for five wood species with an ideal recognition velocity. The selected feature wavelengths by using of our feature selection algorithm based on dispersion matrix are mainly in the near infrared band..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2425 (2016)
Structural Analysis and Optimization Performance Forecast of SiO2-Based Phase Change and Humidity Storage Composite Materials with Fourier Transform Infrared Spectrum
SHANG Jian-li, ZHANG Hao, XIONG Lei, and MA Xiang-long
SiO2-based phase change and humidity storage composite materials with phase change thermal control performance and humidity storage humidity control performance were made with SiO2 as the carrier and fatty acid as a phase change material. Phase change thermal control performance and humidity storage humidity control peSiO2-based phase change and humidity storage composite materials with phase change thermal control performance and humidity storage humidity control performance were made with SiO2 as the carrier and fatty acid as a phase change material. Phase change thermal control performance and humidity storage humidity control performance of SiO2-based phase change and humidity storage composite materials with different fatty acid content were tested with isothermal sorption method and cooling curve method. Composition structure of SiO2-based phase change and humidity storage composite materials were tested by Fourier transform infrared spectrum to analyze chimeric mechanism of SiO2 and fatty acid. Characteristic FTIR absorption peaks of SiO2-based phase change and humidity storage composite materials were considered as input layer; different fatty acid content of SiO2-based phase change and humidity storage composite materials, average values of absorption equilibrium moisture content and desorption equilibrium moisture content of SiO2-based phase change and humidity storage composite materials with relative humidity as 52.89%, and cooling time from 30 to 15 ℃ of SiO2-based phase change and humidity storage composite materials were seen as output layer respectively; S activation function was treated as hidden layer; then, optimization performance forecast model of SiO2-based phase change and humidity storage composite materials with structural parameters and phase change and humidity storage comprehensive performance was established by back-propagation neural network. The results showed that SiO2 and fatty acid are only physical chimeric to each other, while there is no chemical reaction between them. SiO2-based phase change and humidity storage composite materials by adding in 0.079 mol fatty acid has the best phase change and humidity storage comprehensive performance, that is, absorption equilibrium moisture content is 0.132 3 g·g-1, desorption equilibrium moisture content is 0.147 5 g·g-1, average value of equilibrium moisture content is 0.139 9 g·g-1 when relative humidity is 52.89%, cooling time from 30 to 15 ℃ is 1 305 s. Optimization performance forecast model of SiO2-based phase change and humidity storage composite materials are proved well with good accuracy, and the relative error of predicted data and experimental data are -2.07% and 2.45%, respectively; forecast model can be used for optimizing forecast phase change thermal control performance and humidity storage humidity control performance of SiO2-based phase change and humidity storage composite materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2430 (2016)
Near Infrared Spectroscopy Wavelength Selection Method and the Application Based on Synergy Interval Gaussian Process
XU Chen, YIN Yan-yan, and LIU Fei
Based on Gaussian Process (GP), a wavelength selection algorithm named Synergy Interval Gaussian Process (siGP) model is proposed in this paper by using near infrared spectroscopy technology. Full spectrum is divided into a series of unique and equal spacing intervals, before selecting optimal several intervals to estaBased on Gaussian Process (GP), a wavelength selection algorithm named Synergy Interval Gaussian Process (siGP) model is proposed in this paper by using near infrared spectroscopy technology. Full spectrum is divided into a series of unique and equal spacing intervals, before selecting optimal several intervals to establish GP model. Due to the GP model with nonlinear processing ability, the method reduces the disadvantages of nonlinear factor. Taking the near infrared spectrum data of moisture content and pH in solid-state fermentation of monascus as performance verification object of this new algorithm, the prediction correlation coefficient (Rp) of moisture content and pH are 0.956 4 and 0.977 3, respectively. The root mean square errors for prediction set (RMSEP) are 0.012 7 and 0.161 0, respectively. Data points participating in modeling decrease respectively from the original 1 500 to 225 and 375. In the prediction for independent samples, it shows good accuracy. Comparing with traditional synergy interval partial least squares (siPLS) algorithm, the results show that the siGP achieves the best prediction result. The prediction correlation coefficient of moisture content and pH in new algorithm has increased respectively by 3.37% and 3.51% under the model of Gaussian Process, with increases of 29.4% and 34.8% in the root mean square errors for prediction set. This study shows that the combination of siGP and GP model can select wavelength effectively and improves the prediction accuracy of the NIR model. This method is reference for realizing the online detection and optimization control..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2437 (2016)
FTIR Analysis of Secondary Abiotic Stress Response of Calendula Officinalis Seedlings to Lead and Cadmium in Multi-Contaminated Loess
FAN Chun-hui, CHANG Min, ZHANG Ying-chao, and GAO Ya-lin
As an environmentally-friendly technology attracting great attention from current researchers, phytoremediation is significant for site remediation contaminated by heavy metals. The plant will appear related physiological response to reduce direct harm caused by the stress of heavy metals. The microscale behavior is alAs an environmentally-friendly technology attracting great attention from current researchers, phytoremediation is significant for site remediation contaminated by heavy metals. The plant will appear related physiological response to reduce direct harm caused by the stress of heavy metals. The microscale behavior is always multi-dimensional and difficult to detect. The advanced instruments are effective to resolve the scientific issues, while the related researches are seldom investigated. Taking calendula officinalis seedlings as experimental samples, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were applied to compare the surface characteristics and functional groups variation, respectively. The response process and tolerance mechanism of calendula officinalis seedlings to lead and cadmium stress were further analyzed. The results showed: with the increasing concentration of lead and cadmium in loess, the calyptra of calendula officinalis seedlings become bending and wilting; the amount of root hairs decreases greatly while no significant variations of aerial parts are found on surface characteristics. The stress of lead and cadmium are responsible for the difference of FTIR spectra of Calendula officinalis seedlings. The peak absorbance at 3 573 cm-1 decreases and the peak becomes more complex with the increasing contents of lead and cadmium. It might be the coordination effect between lead/cadmium and hydroxyl, which affects the synthesis and secretion of organic matters. The movement of C—H vibration peak is associated with the lipid oxidationwhile the changes at 1 631 and 1 574 cm-1 suggest the protein component differences. The shifting peak at 1 385 cm-1 might be associated with the methylation of pectin and lipid, and the behavior is positive for the adaption process of calendula officinalis seedlings to lead and cadmium stress. The FTIR spectra are effective to reveal the phytoremediation mechanism on heavy metals contamination in pedosphere..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2442 (2016)
Study on the Selection of Parameters for Evaluating Drug NIR Universal Quantitative Models
FENG Yan-chun, ZHANG Qi, and HU Chang-qin
In order to find out the optimum combination of the evaluation parameters for the selection of the best drug near infrared (NIR) universal quantitative model during model optimization, 13 common evaluation parameters of NIR quantitative models were collected and arranged from commercial chemometrics software or referenIn order to find out the optimum combination of the evaluation parameters for the selection of the best drug near infrared (NIR) universal quantitative model during model optimization, 13 common evaluation parameters of NIR quantitative models were collected and arranged from commercial chemometrics software or references based on the requirements of validation of quantitative analytical procedures of ICH (International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use). Then all these parameters of 92 drug NIR universal quantitative models were calculated and analyzed. By studying the correlation of these parameters, the optimum combination of evaluation parameters for drug NIR universal quantitative models was determined. And the value range of these parameters in the optimum combination was also obtained. Root mean square error of cross-validation(RMSECV)/root mean square error of prediction (RMSEP), average relative deviation (ARD) and ratio of (standard error of) prediction (validation) to (standard) deviation (RPD) were used as the key parameters to evaluate the model accuracy. Most of RMSECV/RMSEP was within 3%, and the value of RMSECV was roughly equivalent to the average absolute deviation of the corresponding model. Most of RPD was more than 2. The value of ARD was related to the type of universal models (such as the drug preparation and packing) and the content range which the test sample belonged to. Determination coefficient (R2) was used as the key parameter to evaluate the model linearity and most of its values were from 80% to 100%. The ratio of RMSEP to RMSECV was selected as the key evaluation parameter of model robustness and its value was usually within 1.5. The standard deviation of repeated measurement data was chosen to evaluate model precision. And it was an important parameter for standardizing operation of NIR instruments and studying the feasibility of model transfer in different instruments. However, the parameter for NIR universal quantitative models received much less attention in previous studies and it was difficult to give a value range for this parameter at present. All the results can not only provide evidence for evaluation of drug NIR universal quantitative models for the model builders or users, but also supply basic data to establish and improve the parameter evaluation system of drug NIR universal quantitative models. Near infrared spectroscopy; Universal quantitative models; Model optimization; Evaluation parameters; Accuracy; Linearity; Precision; Robustness.
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2447 (2016)
The Preparation and Characterization of a New Solid Coagulant: Polymeric Ferric Silicate Sulfate
ZHU Guo-cheng, LIU Jun-fei, ZHOU Teng-zhi, ZHANG Peng, REN Bo-zhi, ZHENG Huai-li, LIU Yun-si, and LI Xue-mei
As one of the most important water treatment agents, polysilicate coagulant, has been playing an important role in coagulation- flocculation, but it is prone to lose stability due to self-polymerization and the forming of silica gel. Therefore, research on the preparation of stable polysilicate coagulant has attract grAs one of the most important water treatment agents, polysilicate coagulant, has been playing an important role in coagulation- flocculation, but it is prone to lose stability due to self-polymerization and the forming of silica gel. Therefore, research on the preparation of stable polysilicate coagulant has attract great attention. A new method to prepare a stable polysilicate coagulant (PSPF), was proposed in this paper. Its structure and morphology were characterized by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) respectively. Fe species in PSPF was analyzed via Fe-Ferron complexation timed spectrophotometric method. The performance of PSPF was assessed by measuring micro-polluted water treatment efficiency. Primary chemicals, such as ferrous sulfate, sodium silicate, potassium dihydrogen phosphate, sodium carbonate, were used. The influence of those parameters affecting the preparation of PSPF, such as nSi/nFe, nP/nFe and nOH/nFe molar ratios were examined. The results showed that nSi/nFe of 1∶4, nP/nFe of 1∶6 and nOH/nFe of 1∶10 under 60 ℃ water bath for 30 min was the optimum condition for preparation. The FTIR spectrum indicated that PSPF was a kind of high molecular polymer, containing new groups (e.g., Si—O—Si and Fe—O—Si), which could increase the molecular weight, molecular chain and coagulation-flocculation efficiency. PSPF presented a cluster appearance similar to a network structure, which was conductive to adsorption-bridging capacity and precipitation sweeping. The increase of Fe(b) and Fe(c) as a result of Si increasing in PSPF improved the polymerization and solidification. The coagulation behaviors of PSPF that were largely affected by the coagulant dosage and pH, indicated that for pH and dosage at 6 and 8 mg·L-1, respectively, the residual turbidity and UV254 removal efficiency could achieve 0.33 NTU and 58.6%, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2455 (2016)
Quantitative Analysis of Deep-Frying Oil Adulterated Virgin Olive Oil Using Vis-NIR Spectroscopy with iPLS
XIAN Rui-yi, HUANG Fu-rong, LI Yuan-peng, PAN Sha-sha, CHEN Zhe, CHEN Zhen-qiang, and WANG Yong
To explore a rapid and reliable method for quantitative analysis of deep-frying oil adulterated virgin olive oil, visible and near infrared(Vis-NIR) spectroscopy and three improved partial least squares methods, including interval Partial Least Squares (iPLS), synergy interval partial least squares (SiPLS) and backwardTo explore a rapid and reliable method for quantitative analysis of deep-frying oil adulterated virgin olive oil, visible and near infrared(Vis-NIR) spectroscopy and three improved partial least squares methods, including interval Partial Least Squares (iPLS), synergy interval partial least squares (SiPLS) and backward interval partial least squares (BiPLS) were employed to establish predicting models of doping content based on virgin olive oil adulterating different levels and different types of deep-frying oil. And the models were compared in order to choose the best one. The Vis-NIR spectroscopy ranged from 400 to 2 500 nm was obtained directly from the adulterated samples, and the spectroscopic data was preprocessed with Savitzky-Golay (SG). Then, the samples were divided into calibration set and test set by Sample Set Partitioning based on Joint X-Y Distance (SPXY) after rejecting the odd samples. At last, the predicting models of doping content were built by using different interval partial least squares methods. The results showed that the optimal model for predicting the doping content of deep-frying soybean oil in virgin olive oil was obtained with SiPLS method that separated the whole spectra into 20 intervals and combined the fourth and the sixteenth intervals. The SiPLS model had correlation coefficient (r) of 0.998 9 and root mean standard error of prediction (RMSEP) of 0.019 2. In addition, for deep-frying peanut oil adulterated virgin olive oil, the SiPLS and BiPLS models with interval 2 and interval 16 which the whole spectra was separated into 20 intervals, had same results. The RMSEP was 0.012 0, lower than iPLS model. Moreover, compared to SiPLS method, BiPLS method saved computation and was more efficient. Overall, through selecting the effective wavelength range, SiPLS method and BiPLS method could accurately predict the doping content of deep-frying oil in virgin olive oil based on its’ Vis-NIR spectroscopy. In addition, this fast and nondestructive experiment doesn’t need sample pretreatment with advantages of no environment pollution, easy operation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2462 (2016)
Study on Gentiana Rigescens with Silvomedicinal and Agriosivomedicinal Systems with FTIR Spectroscopy
SHEN Yun-xia, ZHAO Yan-li, ZHANG Ji, JIN Hang, and WANG Yuan-zhong
Multiple cropping systems are the way to cope with the shortage of traditional Chinese medicine (TCM) resources and enhance the utilization ratio of land. The aim of this study was to investigate seventy Gentiana rigescens Franch samples which were planted in slope and in multiple cropping system mixed with Juglans regMultiple cropping systems are the way to cope with the shortage of traditional Chinese medicine (TCM) resources and enhance the utilization ratio of land. The aim of this study was to investigate seventy Gentiana rigescens Franch samples which were planted in slope and in multiple cropping system mixed with Juglans regia, Alnus nepalensis, Eucalyptus robusta, Alnus nepalensis, Camellia sinensis, Chaenomeles sinensis using Fourier transform infrared (FTIR) spectroscopy. The pretreatments such as baseline correction, normalization and second derivative of all the original spectra were performed with Omnic 8.0 software. Moreover, second derivative spectra of samples and gentiopicroside standard were analyzed. In addition, two spectral databases were set up based on the average spectra of every variety with Omnic 8.0 software. The first library (Lib1) which included the spectra region from 1 800 to 600 cm-1 had the algorithm of expert retrieve while the correlation retrieve and square differential retrieve were dealt with the second library (Lib2) in the full spectral range. The results indicated that it is difficult to identify the infrared spectra of samples directly because they had high similarities. There were multiple common peaks between spectra of samples and gentiopicroside standards. The absorption peaks of 1 611 and 1 076 cm-1 of gentiopicroside were the two main characteristic peaks in the second derivative spectra. The difference of peak shape of every sample in the wave number of 1 076 cm-1 was small. By comparing peak area at 1 611 cm-1, the samples planted with J. regia contained highest content of gentiopicroside while the content of this effective constituent was the lowest in the samples which were planted in the slope and in the multiple cropping systems mixed with C sinensis. The differences of effective components in the samples with different planting patterns were represented by the variances of spectral matching values. The difference of matching values of samples planted with J. regia, A. nepalensis, E. Robusta and A. nepalensis were lower than that with slope and C. Sinensis. The number of misjudgment of expert retrieval, correlation retrieve and square differential retrieve were 11, 4 and 9, respectively. The discrimination result of correlation retrieve was the best in the full spectral range and the correct recognition rate was 94.29%. Fourier transforms infrared (FTIR) spectroscopy combined with second derivative and retrieval had good ability to discriminate G. rigescens with different cropping systems. It could provide a basis for the discrimination of different planting patterns of TCM.
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2468 (2016)
Method for the Discrimination of the Variety of Potatoes with Vis/NIR Spectroscopy
CHEN Zheng-guang, LI Xin, and FAN Xue-jia
Potato (Solanum tuberosum L.) , as one of the most important carbohydrate food crops in the China ranking thefourth after rice, wheat and maize, plays a significant role in national economy. Since there are many varieties of potato, the quality such as physical sensory property and chemical components, differ drasticalPotato (Solanum tuberosum L.) , as one of the most important carbohydrate food crops in the China ranking thefourth after rice, wheat and maize, plays a significant role in national economy. Since there are many varieties of potato, the quality such as physical sensory property and chemical components, differ drastically with the variety of potato. Different potato varieties are suitable for different utilization. Thus, the rapid and nondestructive identification of potato cultivars plays an important role in the better use of varieties. Near infrared (NIR) spectroscopy has raised a lot of interest in the classification and identification of agricultural products because it is a rapid and non-invasive analytical technique. In this study, a rapid visible (VIS) and near infrared (NIR) spectroscopic system was explored as a tool to measure the diffuse spectroscopy of three different species of potatoes. 352 potato samples (Sample A 142, Sample B 84, Sample C 126) from different sites in Heilongjiang province of China, obtained from peddlers market, were randomly divided into two sets at random: calibration set and prediction set, with 307 samples and 45 samples respectively for each set. The potatoes in the calibration set were tested with visible-near infrared spectroscopy method. The spectral data obtained from this test were analyzed with near infrared spectral technology, along with data processing algorithm, i.e., Savitzky-Golay (S-G) smoothing and multiplicative scatter correction (MSC). The spectra data was firstly transformed by multiplicative scatter correction (MSC) to compensate for additive and/or multiplicative effects. In order to reduce the noise components from a raw spectroscopic data set, Savitzky-Golay smoothing and differentiation filter method were introduced. It was proved that, with the soothing segment size of 9, many high frequency noises components can be eliminated. Based on the following analysis with principal component analysis (PCA), partial least square (PLS) regression and back propagation artificial neural network (BP-ANN), a near infrared discrimination model was established. The results obtained from the partial least squares (PLS) analysis showed a positive cumulate reliability of more than 96% for the first four components. The clustering effect was also getting better. After that, twenty absorption peaks extracted from the first four principal components were applied as BP neural network inputswhile a three layers BP neural network ［20(input) - 12(implicit) - 3 (output)］ was constructed, upon which the recognition accuracy of potato varieties for those Prediction Set samples reaches 100%. As a result, the model established in this study can rapidly and accurately identify potato varieties without any destruction, which provides a new way for potato quality detection and variety identification..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2474 (2016)
Discrimination of Seven Species of Boletus with Fourier Transform Infrared Spectroscopy
MA Dian-xu, LIU Gang, OU Quan-hong, YU Hai-chao, LI Hui-mei, and LIU Yan
Fourier transform infrared spectroscopy, two-dimensional correlation infrared spectroscopy and principal component analysis were used to discriminate seven species of boletus belonging to the same genus. The results showed that the absorption bands of original spectra were similar, which were mainly composed of the absFourier transform infrared spectroscopy, two-dimensional correlation infrared spectroscopy and principal component analysis were used to discriminate seven species of boletus belonging to the same genus. The results showed that the absorption bands of original spectra were similar, which were mainly composed of the absorption bands of protein and polysaccharides, but tiny differences were still observed at the position and intensities of peaks. Two-dimensional correlation infrared spectroscopy technology was applied to study the sample. It showed that there are 6 auto-peaks in the Boletus brunneissimus Chiu and Boletus bicolor, 5 auto-peaks in the Boletus speciosus, 4 auto-peaks in the Boletus griseus Forst and Boletus calopus, only 3 in the Boletus edulis and Boletus aereus in the range of 1 680~1 300 cm-1. The significant differences in the position, intensity of auto-peaks and cross peaks were still observed in the range of 1 680~1 300 cm-1. Same significant differences were observed in the range of 1 150~920 cm-1. Principal component analysis was conducted on boletus with second derivative infrared spectra in the range of 1 800~800 cm-1. All the samples were distinguished and the classification accuracy of principal component analysis is up to 100%. It is demonstrated that Fourier transform infrared spectroscopy combined with two-dimensional correlation infrared spectroscopy or principal component analysis is a rapid and effective method for discriminating mushrooms..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2479 (2016)
Design of Raman Spectroscopy Rapid Detection System for Synthetic Edible Pigment Based on PERS
FAN Xian-guang, LIANG Jun, WANG Xin, XU Ying-jie, QUE Jing, and ZUO Yong
Based on Plasmon-enhanced Raman Spectroscopy (PERS) technology, the detection system for rapid field determination of synthetic edible pigments in food, such as beverage, meat productsand preserves, is presented. The hardware framework of this detection system is mainly composed of double central control chips (ARM andBased on Plasmon-enhanced Raman Spectroscopy (PERS) technology, the detection system for rapid field determination of synthetic edible pigments in food, such as beverage, meat productsand preserves, is presented. The hardware framework of this detection system is mainly composed of double central control chips (ARM and FPGA), a sample pretreatment module (containing a nanoparticle giving device), a laser diode source, and a spectral data acquisitioning module; Besides, the software can run the sample pretreatment module automatically while receiving the Raman spectrogram. To verify its performance in edible synthetic pigments, the rapid detection system was applied to determine carmine, citrine, allure red in three actual samples (i.e. preserves, sodas, sausage). The relative standard deviations of the sample detection were in the range of ±5%, which indicated that the system developed in this paper have the advantage of favorable sensitivity, excellent repeatability and short testing time. Thus, it meets the requirements for rapid field determination of synthetic pigments in food..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2487 (2016)
The Detection of Raman Spectra on Dissolved Gas in Transformer Oil and Its Spectral Linear Model Analysis
CHEN Xin-gang, LI Song, MA Zhi-peng, NI Zhi, YANG Ding-kun, and TAN Hao
Raman spectroscopy gas detection technology which uses a single wavelength laser detection of gas samples without contact and loss is suitable for dissolved gas detection in oil-immersed transformers. Combined with the features of Raman spectral lines, the analysis of the detection mechanism in Raman spectroscopy technRaman spectroscopy gas detection technology which uses a single wavelength laser detection of gas samples without contact and loss is suitable for dissolved gas detection in oil-immersed transformers. Combined with the features of Raman spectral lines, the analysis of the detection mechanism in Raman spectroscopy technology has been made. Raman spectral lines have been presented in the expression of the convolution of Lorentz function and Gaussian function, which shows preferable Raman spectrum peak linear outline basic characteristics. In this paper, the basic features of the peak height, the peak position and the half peak width, are the main targets of peak searching, and the fundamental purpose of this paper is to obtain qualitative and quantitative analysis of the sample. Therefore, the experimental data of Raman spectroscopy is designed based on the comparison method to realize the automatic peak seeking model to achieve the detection target. Therefore, according to the automatic peak searching model based on the comparison method is designed to achieve the detection target. The simulation results of using peak searching model in the Voigt linear model show that spectrum peak height and peak position are in conformity with the theory in the test experiment. Based on the establishment of Raman spectroscopy detection platform aiming at the dissolved gas in transformer oil, the analysis of the experimental data show that the actual values of the half peak height and width are （8.7, 11.5）（cm-1）in the Voigt linear model with deviations. Setting the value as 10.257 cm-1 to modify the parameter, then compared with the research results, it shows that the modified Voigt linear model and the peak searching model have better adaptability and practicability. Combined with the gas detection in the experimental platform in the experimental platform of Raman spectroscopy,detection of seven kinds of transformer fault characteristic gas and analysis of peak searching have been completed effectively. In terms of methane gas, the linear relationship among the unit gas content, Raman characteristic peak intensity and the area has been obtained, which has laid a foundation for the quantitative analysis of the dissolved gas in transformer oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2492 (2016)
Analysis of Endocrine Disruptor: Triphenyltin Chloride with Raman Spectroscopy
JIANG Juan, GAO Jun-min, GUO Jin-song, LIU Xiao-hong, ZHOU Qiu-hong, and OUYANG Wen-juan
Triphenyltin Chloride (TPhT) is one of the only two kinds of metal compounds known in the endocrine disruptors. TPhT is widely used in industry, agriculture and transportation fields, which can cause great impact on soil, marine and inland freshwater environment. This experiment collects the Raman signal of TPhT standaTriphenyltin Chloride (TPhT) is one of the only two kinds of metal compounds known in the endocrine disruptors. TPhT is widely used in industry, agriculture and transportation fields, which can cause great impact on soil, marine and inland freshwater environment. This experiment collects the Raman signal of TPhT standard powders by applying laser confocal Raman spectroscopy to explore the feasibility of the method and to acquire optimized parameters. In this paper, we combined the application of laser confocal Raman spectroscopy with TPhT physical property. Due to different functional groups of TPhT molecules shows different vibration modes, the Raman spectra was divided into three wavenumber areas(1 500~3 200, 900~1 500 and 100~900 cm-1) to attribute and analyze their assignments of the Raman peaks, obtaining the characteristics of TPhT vibration modes and the corresponding characteristic peaks. Finally, a standard Raman spectra library was established with the spectral range between 100~3 200 cm-1. The results showed that the Raman spectra with high signal-to-noise ratio can be obtained in a short time when the laser power options decayed to 0.5% of the original power (500 mW) after 10s exposure and 2 times integration. Strong Raman signals observed in the Raman spectroscopy at 212, 332, 657, 997 and 1 577 cm-1 could be used as the characteristic peaks of TPhT in Raman detection. Otherwise, the co-occurrence of the Raman peaks at 657 and 997 cm-1 can be considered as the presence of TPhT in complex environmental samples. Experimental results are given to identify the presence of TPhT. The results would be used to identify the presence of TPhT residual in real environmental samples, which provide a theoretical basis and data base on Raman spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2499 (2016)
The Analysis of Raman Spectra of Particulate Matters Emitted from Biodiesel-Diesel Blend Fuels
ZHANG Jian, WANG Zhong, QU Lei, and ZHAO Yang
In order to further reduce particulate matter from diesel engine fuelled with biodiesel. Raman spectroscopy was used to investigate the microstructure of particulate matters with and without exhaust gas recirculation (EGR). Five-band fitting curves were adopted for first-order Raman spectrum. In addition, graphite crysIn order to further reduce particulate matter from diesel engine fuelled with biodiesel. Raman spectroscopy was used to investigate the microstructure of particulate matters with and without exhaust gas recirculation (EGR). Five-band fitting curves were adopted for first-order Raman spectrum. In addition, graphite crystallite size and C—C bond distance in graphite lattice were calculated. The results showed that D1 full width at half maximum (FWHM) increased and ID1/IG decreased with the increasing of blend of biodiesel. D1 FWHM increased and ID1/IG increased with EGR. These showed particulate matters from biodiesel and blend oil had higher chemical heterogeneity and more ordered graphite structure. EGR made particulate matters become higher chemical heterogeneity and less ordered graphite structure. The main kind of particles’ defect was located at the edge of graphite. The concentration of defect, volatile organic compounds (VOF) in particulate matters increased with biodiesel addition or EGR, indicating oxidation reactivity of particulate matter. Biodiesel addition to diesel made graphite crystallite size larger and EGR made graphite crystallite size smaller. In addition, biodiesel and EGR had slight influence on C—C bond distance in graphite lattice. The C—C bond distance in graphite lattice is about 0.142 nm..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2505 (2016)
Statistical Characteristics of Raman Shift of Petroleum Components Ⅰ: Alkanes and Aromatic Hydrocarbons
CHEN Yong, LIU Wei-yi, and WANG Xin-tao
Hydrocarbon inclusions play an important role in the study of petroleum-bearing basin in terms of the generation, migration and accumulation of hydrocarbons. It's important to understand petroleum basin by determining hydrocarbon molecules in hydrocarbon inclusions. Laser Raman spectroscopy has been widely used as Hydrocarbon inclusions play an important role in the study of petroleum-bearing basin in terms of the generation, migration and accumulation of hydrocarbons. It's important to understand petroleum basin by determining hydrocarbon molecules in hydrocarbon inclusions. Laser Raman spectroscopy has been widely used as a non-destructive assay methods for individual fluid inclusion analysis. However, this method is restricted in two aspects of the application on the hydrocarbon inclusion. One is that the complexity of petroleum which molecular is difficult to be identified. Another is that the Raman signal is usually covered by the fluorescence of most hydrocarbon inclusion. This article summarizes Raman spectroscopic characteristics of chain alkanes (n-alkanes and iso-alkanes) and aromatic hydrocarbons. According to our statistical results, some important conclusions can be reached. The normal alkanes of carbon number more than 10 can be identified by three Raman bands at 1 438, 2 890 and 2 850 cm-1. Iso-alkanes (take C8H18 as an example) containing two chains can be identified by a stable strong Raman peak at 2 875 cm-1. The strongest Raman peak combination of C—C (1 450 cm-1) and C—H (2 875 cm-1) is the evidence of the iso-alkanes containing one chain. Aromatic hydrocarbon containing one benzene ring can be identified by stable Raman band 1 600 cm-1 with two peaks. The combination of strongest Raman peaks of 1 005 and 3 060 cm-1 is the evidence of the aromatic hydrocarbon containing single chain, while the strongest Raman peaks of 1 250 and 2 910～2 920 cm-1 are the evidence of the aromatic hydrocarbon containing three chains. Aromatic hydrocarbons containing two benzene rings can be identified by stable Raman bandat 1 600 cm-1 double peaks and a strongest Raman peaks at 3 060 cm-1. All these typical Raman bands can be used to identify alkanes and aromatic hydrocarbons. The Raman spectroscopy-meter with short wavelength exciting light (blue to ultraviolet light) can effectively avoid fluorescence interference..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2510 (2016)
Advances in Raman Spectroscopy for Nasopharyngeal Carcinoma Tissue
XU Zhi-hong, HUANG Wei, LIN Duo, GE Xiao-song, LIN Xue-liang, FENG Shang-yuan, LI Yong-zeng, and CHEN Rong
Nasopharyngeal carcinoma is a unique malignant tumor that has a distinct geographic and racial distribution, with a high incidence in southeast Asia and southern China. High degree of malignancy, poor prognosis and difficulty in early diagnosis remain a problem in nasopharyngeal carcinoma. Raman spectroscopy technique Nasopharyngeal carcinoma is a unique malignant tumor that has a distinct geographic and racial distribution, with a high incidence in southeast Asia and southern China. High degree of malignancy, poor prognosis and difficulty in early diagnosis remain a problem in nasopharyngeal carcinoma. Raman spectroscopy technique based on inelastic scattering is a rapid and nonivasive detection method, which is capable of providing the information of biochemical components at molecular vibration level.This article reviewed the recent research progress of nasopharyngeal carcinoma based on Raman spectroscopy. It mainly introduces the study of detecting nasopharyngeal carcinoma tissue by using Raman spectroscopy as well as surface-enhanced Raman scattering spectroscopy (SERS). The emphasis is put on the latest works by our research group, including high wavenumber Raman spectroscopy of tissue, Raman spectroscopy of tissue smears, and a specially designed endoscopic device combined with Raman spectroscopy for in vivo nasopharyngeal cancerous tissue detection, which was firstly developed by our group. Finally, the prospects of the development of Raman spectroscopy for nasopharyngeal carcinoma were discussed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2518 (2016)
Fluorescence Properties and the Detection of Nitrobenzene of Lanthanides Complex with 3,4-Thiophenedicarboxylic Acid and 1,10 Phenanthroline
LI Rui, FAN Ting-ting, QU Xiang-long, DONG Gao-yun, LI Jia-jia, LI Xia, SONG Yu-xin, ZHAO Xin-meng, and LI Xiang
3,4-thiophenedicarboxylic acid (3,4-H2tdc) as the first ligand, 1,10-phenanthroline (phen) as the auxiliary ligand, three complexes Ln2(Htdc)2(tdc)2(phen)2(H2O)4(Ln=Eu 1, Gd 2, Tb 3) were synthesized with hydrothermal method. Single-crystal X-ray diffraction analysis reveals that complexes 1-3 were isostructural crysta3,4-thiophenedicarboxylic acid (3,4-H2tdc) as the first ligand, 1,10-phenanthroline (phen) as the auxiliary ligand, three complexes Ln2(Htdc)2(tdc)2(phen)2(H2O)4(Ln=Eu 1, Gd 2, Tb 3) were synthesized with hydrothermal method. Single-crystal X-ray diffraction analysis reveals that complexes 1-3 were isostructural crystallize and both of complexes are binuclear molecules. In the complexes 1-3, the coordination number is nine. Each metal is bound to two 3, 4-tdc ligand, one 3,4-Htdc ligand, one phen and two water molecule. Complexes 1 and 3 display the red and green light under UV lamp, corresponding the characteristic peaks from 619 nm (5D0→7F2) and 545 nm (5D4→7F5). Complex 2 expresses a broad band at 425 nm is attributed to π*→π transition. Furthermore, under the excitation wavelength of 329 nm, the effects of different solvents on complex 1 was discussed and complex 1 could be a potential luminescent probe for detecting nitrobenzene through fluorescence quenching mechanism..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2522 (2016)
［Zn-(CH3CH2OH)n］2+ Clusters Probed with Fluorescence Spectroscopy and Computation
WU Xiao-jing, JIANG Wei-guo, YU Ya-peng, YU Xue-hui, and CHENG Long-jiu
In this paper the cluster structures of ［Zn-（CH3CH2OH）n］2+ have been investigated with spectroscopic experiment and theoretical calculation. According to the fluorescence spectroscopy experiments, the fluorescence peak of ethanol molecules was found between 275~330 nm. A new peak appeared between 350~380 nm after the mIn this paper the cluster structures of ［Zn-（CH3CH2OH）n］2+ have been investigated with spectroscopic experiment and theoretical calculation. According to the fluorescence spectroscopy experiments, the fluorescence peak of ethanol molecules was found between 275~330 nm. A new peak appeared between 350~380 nm after the metal ions (Zn2+) was added into ethanol solution due to the generation of new clusters of molecules, and the original fluorescence peak of ethanol molecules became weak owing to the destroyed structure of ethanol molecules induced by Zn2+. The cluster structures of Zn2+ in water solution were investigated by using different methods. By comparing the results, a more accurate and fast B3LYP method of DFT was found and applied to optimize the possible structures of ［Zn-（CH3CH2OH）n］2+. The results suggested that the first solvation shell of the system is up to six ethanol molecules, and thermodynamic parameters also shows the six kinds of molecular clusters which are likely in the solution. Moreover compared the theoretical fluorescence spectroscopy with experimental fluorescence spectroscopy, new clusters ［Zn-（CH3CH2OH）n］2+ have been generated, with ［Zn-（CH3CH2OH）n］2+(n=1~3) as main constructions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2527 (2016)
Studied on Colored Dissolved Organic Matter of Spring in North Yellow Sea with Three-Dimensional Fluorescence Spectroscopy Combined with Parallel Factor Analysis
YAO Yi-liang, ZHAO Wei-hong, and MIAO Hui
This paper conducted fluorescent spectra of dissolved organic matter of Spring China North Yellow Sea by using three-dimensional fluorescence spectroscopy (EEMs) combined with parallel factors analysis (PARAFAC). The results showed that the fluorescent dissolved organic matter (FDOM) in colored dissolved organic matterThis paper conducted fluorescent spectra of dissolved organic matter of Spring China North Yellow Sea by using three-dimensional fluorescence spectroscopy (EEMs) combined with parallel factors analysis (PARAFAC). The results showed that the fluorescent dissolved organic matter (FDOM) in colored dissolved organic matter (CDOM) of North Yellow Sea could be resolved to four components. Two components, c1 (260,315/425) and c2 (295,355/490) were identified as humic-like fluorescence components while c3 (275/310) and c4 (230,290/345) were protein-like components. The different linear correlations showed different degrees of similarities in the source or the chemical constitution, the relationship of the humic-like fluorescence components were most closely, followed by protein-like components. Four fluorescent components and total fluorescence intensity (TFI) in the horizontal and vertical directions had a higher intensity in coastal area than that of the area far away from the coast. Additionally, besides terrestrial input, the seawater mass movement also affects the distribution of CDOM in North Yellow Sea. Cluster analysis not only further illustrated the TFI characteristics of different areas of the North Yellow Sea, but also reflects the overall uniformity of the CDOM. Fluorescence Index (FI), Humification Index (HIX) and Biological Index (BIX) at some extent indicated the source of North Yellow Sea CDOM and the conclusion was that the near shore side gets greater influence from terrigenous sources while the sea side is more impacted by biological activity, which matched with the prior distribution patterns of fluorescence components..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2532 (2016)
Simulation of Needle Reflectance Spectrum and Sensitivity Analysis of Biochemical Parameters of Pinus Yunnanensis in Different Healthy Status
LIN Qi-nan, HUANG Hua-guo, CHEN Ling, YU Lin-feng, and HUANG Kan
The sensitivity of biochemical effects on leaf reflectance is vital for retieving biochemical parameters with remote sensing. In this study, the chlorophyll and water absorption coefficients of the commonly used model LIBERTY (leaf incorporation biochemistry exhibiting reflectance and transmittance yields) were calibraThe sensitivity of biochemical effects on leaf reflectance is vital for retieving biochemical parameters with remote sensing. In this study, the chlorophyll and water absorption coefficients of the commonly used model LIBERTY (leaf incorporation biochemistry exhibiting reflectance and transmittance yields) were calibrated using field measured needle spectral reflectance curves based on a look up table (LUT) method. A novel spectra reflectance fitting method were presented by involving a new index (named as yellow index, YI), which could obviously improve the fitting accuracy of Pinus yunnanensis reflection spectrum at highly-stressed status. As a global sensitivity analysis method, the EFAST (extended Fourier amplitued sensitivity test) was implemented to quantitatively assess the sensitivity of biochemical parameters on needle reflectance. Results show that: (1) the reflectauce spectrum of healthy needles (R２=0.999, RMSE＜0.01), slightly stressed needles (R2=0.991, RMSE＜0.02) and moderately stressed needles (R2=0.992, RMSE＜0.03) are simulated fairly well by calibrated LIBERTY model which has less potential in fitting the reflectance spectrum of seriously stressed needles (R2=0.803, RMSE＞0.1). (2) the reflectance spectrum of seriously stressed needles can be successfully simulated by our proposed spectrum reflectance fitting method (R2=0.991, RMSE<0.03), because YI can quantitatively describe different degrees of stress, and (3) the sensitivity of leaf reflectance to chlorophyll and water parameters decreases with the degree of stress; while the sensitivity to other biochemical parameters is increasing, which includ baseline absorption, albino absorption, Lignin and Cellulose content, and nitrogen content, increases with the stress degree. Needle reflectance spectrum also have sensitivive bands for these parameters. For example, the albino absorption have a significant effect on needle reflectance in 505～565 and 705～850 nm). In addition, Albino absorption and chlorophyll also have significant effects on needle reflectance in visible region for seriously stressed needles, which indicates that the prior knowledge of the albino absorption level can help obtain the valid inversion result of chlorophyll content..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2538 (2016)
The Research of Vegetation Water Content Based on Spectrum Analysis and Angle Slope Index
DENG Bing, YANG Wu-nian, MU Nan, and ZHANG Chao
Vegetation water content is an important indicator of vegetal state, and a vital parameter of studying agriculture, ecological and hydrological. The diagnosis of vegetation water content has great significance for forest fire forecast and natural vegetation drought condition monitoring. The correlation analysis of the Vegetation water content is an important indicator of vegetal state, and a vital parameter of studying agriculture, ecological and hydrological. The diagnosis of vegetation water content has great significance for forest fire forecast and natural vegetation drought condition monitoring. The correlation analysis of the vegetation spectral reflectance and vegetation water content shows that the relativity between the spectral reflectance of different wavelengths and the vegetation water content varies considerably. The spectral reflectance of red band of visible light (620～700 nm) and the near-infrared band（800～1 350, 1 600～1 950, 2 200～2 400 nm） had a higher correlation with the vegetation water content. The slope angle indexes were used as parameters for estimating the vegetation water content based on analyzing the relation between the slope angle indexes and vegetation water content. An evaluation model of vegetation water content was set up by utilizing statistical linear regression model method. The band of 660, 850, 1 630, 2 200 nm were selected as RED, NIR, SWIR1 and SWIR2 band value of the slope angle index based on the analysis of the correlation between spectral reflectance and vegetation water content. A large amount of vegetation spectral information and vegetation water content were collected in the study area(the upstream of Minjiang River), and the linear regression model of the slope angle index (SANI, SASI, ANIR) and vegetation water content (FMC) was build. The linear regression model of ANIR and FMC has the highest of linear fitting and the linearity is up to 0.791. The near infrared angle index（ANIR）was improved on the basis of the analysis the linear regression results of angle slope vegetation index and water content. Near infrared angle normalized index (NANI) and near infrared angle slope index (NASI) were defined, and the linear regression model was established. Compared with the slope angle index (SANI, SASI, ANIR) which were proposed by Palacios-Orueta, NANI had more advantages in the vegetation water content inversion in the study area. The determination coefficient (R2) of the inversion model increased from 0.791 to 0.853, and root-mean-square error (RMSE) reduced from 0.047 to 0.039. Angle slope index had higher linear fitting and estimation accuracy by improving the angle of slope index. NANI and FMC linear regression model was established to estimate the vegetation water content in the study area. In this paper, the main innovation point is that the slope angle index NANI and NASI has been proposed on the basis of predecessors' research results, and the improved angle slope index has higher linear fitting and estimation accuracy compared with SANI, SASI, ANIR..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2546 (2016)
An Identification Study on Field-Derived Spectra of Grassland Combustibles and Soil Based on Fractal Theory
LUO Xiao-long, TONG Zhi-jun, ZHAO Yun-sheng, and ZHANG Ji-quan
Grassland fire disaster is an important influence factor to grassland ecological system in China. Therefore, it is crucial to study on the monitoring, prediction and management of grassland fire. Remote Sensing (RS) provides detailed data and saves a lot of manpower, material resources and financial resources on the reGrassland fire disaster is an important influence factor to grassland ecological system in China. Therefore, it is crucial to study on the monitoring, prediction and management of grassland fire. Remote Sensing (RS) provides detailed data and saves a lot of manpower, material resources and financial resources on the research of grassland fire. However, it is difficult to identify the grassland fuel and soil with Remote Sensing. In this paper, we introduced fractal into the spectral analyses of the field-derived spectra (FDS) of grassland fuel and soil to solve the problem above. The study area laid on the Westward of Changling, Jinlin province, China. Study subjects included soil and dominant species: Leymus chinensis, Reed, Chloris virgate, Kalimeris integrifolia and Artemisia mongolica. FDS of study subjects were measured with ASD FS3 and continuums of FDS were calculated by Matlab 2010. Meanwhile, Box-counting values of FDS and continuums were calculated by Matlab 2010. According to the spectral and continuum analysis, it is difficult to identify soil, Leymus chinensis, Reed, Chloris virgate, and Artemisia mongolica because of the similar spectral curves. However, the Artemisia mongolica can be identified for the strong reflection. For typical fractal characteristics of FDS and continuum, clustering analyses of study subjects were done according to box-counting values of FDS and continuum. The results of clustering analyses show that Box-counting values of FDS and continuum are important indexes to identify the study subjects. This study provides a new thought to identity the grassland combustibles and soil with Remote Sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2553 (2016)
Spectral Characteristics Analysis of Wheat Damaged by Subsurface Waterlogging
XIONG Qin-xue, WANG Xiao-ling, and WANG You-ning
Spectrum analysis of crop that affected by subsurface waterlogging is the foundation of surface waterlogging monitoring by remote sensing in large scale. It is also the prerequisite of achieving non-destructive, quick identification of wheat subsurface waterlogging damage with spectral features. But there is no papers Spectrum analysis of crop that affected by subsurface waterlogging is the foundation of surface waterlogging monitoring by remote sensing in large scale. It is also the prerequisite of achieving non-destructive, quick identification of wheat subsurface waterlogging damage with spectral features. But there is no papers report about spectrum analysis of crop affected by subsurface waterlogging so far. The paper analysis the spectral features difference of 8 species (zenmai9023, xinong223, luo6010, fumai168, emai23, emai19, guangyuang11-2, nongda195) between affected subsurface waterlogging and normal in leaf and canopy model using field experiment. The results shows that the leaf spectrum reflectivity value of wheat affected by subsurface waterlogging is high in 645～680 and 1 428～1 456 while it is lower in 757～917 and 1 641～1 684 nm. The main reason is that the subsurface waterlogging causes the leaf chlorophyll photosynthetic capacity decreased and leaf water loss. It is suggested to use NDWI (normal differential water index) value to indicate the damage degree of wheat subsurface waterlogging disaster. The changes of the NDWI index value is analyzed with time when difference wheat species demerged by subsurface waterlogging. It is found that the main factors caused the changes of the NDWI index value with time is related with resistance of variety. The canopy spectrum reflectivity value of wheat affected by subsurface waterlogging is low in all spectrum area. It is suggested to use average value in 670～240 nm to indicate the degree of wheat subsurface waterlogging disaster..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2558 (2016)
Analysis on Diurnal Variation of Chlorophyll-a Concentration of Taihu Lake Based on Optical Classification with GOCI Data
BAO Ying, TIAN Qing-jiu, CHEN Min, and L Chun-guang
Chlorophyll-a (Chl-a) concentration is one of the most important parameters for the analysis of inland water quality. Remote sensing data with the advantages of wide spatial area and multi-temporal monitoring has been applied as a reliable source of Chl-a concentration. However, as optical characteristics of inland watChlorophyll-a (Chl-a) concentration is one of the most important parameters for the analysis of inland water quality. Remote sensing data with the advantages of wide spatial area and multi-temporal monitoring has been applied as a reliable source of Chl-a concentration. However, as optical characteristics of inland water bodies are complex with high spatial and temporal (diurnal) variations, there are still limitations to estimate Chl-a concentration with traditional remote sensing data and single model. In the proposed solution, the first geostationary ocean color satellite sensor, Geostationary Ocean Color Imager (GOCI), which provides an image per hour (eight images per day from 8:16 to 15:16), was used as a data source of Taihu Lake. Based on hierarchical clustering method, water types were identified from in situ normalized spectral reflectance collected in Taihu Lake (216 samples in different seasons from 2010 to 2012). Then eight GOCI images which were obtained on May 6th, 2012 were classified separately according to different water types by calculating spectral angle distance between each spectrum in GOCI images and the classified spectra. According to the classified remote sensing images and the spectral bands of GOCI data, classed-based models were subsequently developed for the estimation of Chl-a concentration. The results indicated that four water types (Type 1 to Type 4) were identified based on the in situ normalized spectral reflectance in Taihu Lake. The spectra of Type 1 mainly represented the characteristics of floating algae. This type had little significance to in estimating Chl-a concentration because sensors could only receive signal of floating algae. Then Type 1 was usually used as the evidence of algal blooms. Meanwhile, two-band semi-analytical algorithms were established for Type 2—Type 4 waters which were separately dominated by Chl-a concentration, high suspended solid, low Chl-a and low suspended solid. Comparing with the two-band algorithms, band 7 and band 6 combination was more suitable for Type 2 and Type 3 while the correlation between Chl-a concentration and b7/b5 was higher than that between b7/b6 for Type 4. The accuracies of classification models (Type 2—Type 4) were higher than that of the overall model, with the reduced average relative errors of 7%, 12.3% and 15.9%, respectively. Moreover, the inversion results of GOCI data not only reflected the spatial distribution of Chl-a, but also showed the diurnal variation of the Chl-a concentration of Taihu Lake. This study has demonstrated great potential for dynamic monitoring of eutrophication pollution with GOCI data. In addition, the results suggested that optical classification algorithm can improve the accuracy of Chl-a concentration and the application performance of semi-analytical model. GOCI data and the class-based algorithm provide a basis for accurate estimation of diurnal and spatial variation of Chl-a concentration..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2562 (2016)
DSAT Model on Identifying the Weak Difference Information of Corn Leaf Spectra Stressed by Heavy Metal Lead Ion
YANG Ke-ming, WANG Guo-ping, YOU Di, LIU Cong, and XIA Tian
Weak information measurement between the spectra is one of the toughest current research issues in the hyperspectral remote sensing domainTraditional measuring methods are difficult to distinguish the weak information differences. The experiment on the lead(Pb) pollution was designed based on its different concentratioWeak information measurement between the spectra is one of the toughest current research issues in the hyperspectral remote sensing domainTraditional measuring methods are difficult to distinguish the weak information differences. The experiment on the lead(Pb) pollution was designed based on its different concentrations, meanwhile, the hyperspectral reflectance, chlorophyll and lead ion(Pb2+) contents of corn leaves stressed by different Pb2+ concentrations were measured. However, it is difficult to distinguish the differences on weak information between the spectra and the pollution levels of corn leaves stressed by different Pb2+ concentrations because the spectral correlation coefficients have reached 0.999 according to the measured results. Due to this fact, a novel spectral similarity measuring method that is the derivative spectral angle tangent (DSAT) model, was put forward based on the spectral derivative processing, tangent function enhancement, spectral angle measurement, piecewise spectral detection and so on. In order to verify the feasibility and effectiveness of DSAT in distinguishing the differences of the similar spectra that their correlation coefficients reach 0.99, the DSAT was used to measure the weak information differences between the spectra of corn leaves stressed by different Pb2+ concentrations by the ways on detecting the whole waveforms and the sub-interval waveforms of corn leaf spectra. The experimental results showed that the relative chlorophyll concentration and Pb2+ contents of corn leaves were significantly correlated with the waveform difference information. It also proves that the DSAT model has better practicability and superiority in distinguishing the difference between the high similarity spectra..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2568 (2016)
Study on the Preparation of Zinc Dibenzyl Dithiocarbamate and Its Spectral Analysis
FENG Shi-hong, JIA Tai-xuan, WU Hong-mei, and GUO Yu
In the study, Zinc dibenzyl dithiocarbamate (ZBDC) was synthesized with one-step method. ZBDC was detected and characterized with FTIR, UV-Vis, XRD, TG-DSC. Its micro-structure and intrinsic regularity were revealed. Chemical bond types into ZBDC molecule were revealed with FTIR. The final product was determined as ZBDIn the study, Zinc dibenzyl dithiocarbamate (ZBDC) was synthesized with one-step method. ZBDC was detected and characterized with FTIR, UV-Vis, XRD, TG-DSC. Its micro-structure and intrinsic regularity were revealed. Chemical bond types into ZBDC molecule were revealed with FTIR. The final product was determined as ZBDC. Two absorption peaks were detected with UV-Vis at 209.8, 266.1 nm respectively, due to n→σ*, π→π* electronic transitions. It could provide experimental basis for enterprise to test ZBDC product quality and speculate its structure. ZBDC phase composition and structure were revealed through crystallographic data from XRD detecting such as cell parameters, crystal face index. The phase composition and qualitative identification of ZBDC structure were completed. Two kinds of information were detected with TG-DSC as quality change and thermal effect. There were three absorption peaks of 194.5, 361.1, 433.5 ℃, due to transition peak and decomposition phase of ZBDC respectively. The decomposition temperature of ZBDC was very high. It could provided reference for research on rubber vulcanizing properties with ZBDC on rubber vulcanizing machine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2573 (2016)
A Facile Nanogold Surface Plasmon Resonance Absorption Method for CO Tracing
LIANG Ai-hui, SHANG Guang-yun, ZHANG Xing-hui, WEN Gui-qing, and JIANG Zhi-liang
The detection of gas pollutants in atmosphere and indoor air is very important to human health and safety. Monoxide carbon (CO) is a common gas pollutant with high toxicity that mainly comes from the inadequacy oxidization of carbon such as oil, coal and petrol inadequacy combustion, auto-gas and some natural disastersThe detection of gas pollutants in atmosphere and indoor air is very important to human health and safety. Monoxide carbon (CO) is a common gas pollutant with high toxicity that mainly comes from the inadequacy oxidization of carbon such as oil, coal and petrol inadequacy combustion, auto-gas and some natural disasters whose limit value in air is lower than 6.0 mg·m－3 in the national standard. Due to its toxicity and uneasy detection, it is one of very dangerous component in the silent killer. Recently, several methods, including infra-red absorption, gas chromatography, potentiometry, Hg replacement, spectrophotometry, I2O5 and PdCl2 nake-eye, semiconductor sensor have been reportedly used for the detection of CO. To our best knowledge, there are no SPR absorption methods for CO, based on the NG SPR absorption. In this paper, the reaction between CO and HAuCl4 was studied with absorption spectrophotometry and transmission electron microscopy (TEM)while a simple and rapid SPR absorption method was developed for the determination of trace CO. In pH 7.2 phosphate buffer solutions, monoxide carbon reduced HAuCl4 to form nanogold (NG) particles with the size of about 45 nm that exhibited surface plasmon resonance (SPR) absorption peak at 540 nm and three energy spectral peaks at 1.70 keV, 2.20 and 9.70 keV for gold element. The analytical conditions were examined, and a pH 7.2 phosphate buffer solution with a concentration of 40 mmoL·L-1 PO3-4, a concentration of 40.0 μg· mL-1 HAuCl4 and a reaction time of 5 min was selected for use. Under the selected conditions, the SPR absorption peak value was linear to CO concentration in the range of 0.2～8.75 μg· mL-1, with a detection limit of 0.1 μg· mL-1 CO. According to the procedure, the influence of coexistent substances on the determination of 1.0 mg·L-1 CO was tested, with a relative error of ±5%. Results indicated that 200 times SO2-3, PO3-4, SO2-4, CO2-3 and NO-3, 100 times Zn2+, K+, BrO-3, Na2S, ethanol, methanol, 80 times Ni2+, Cr3+, Co2+, Ca2+, Mg2+, Fe3+, glucose, Pb2+, Al3+, SeO2-3, Na2S2O3, formaldehyde, 50 times Mn2+ do not interfere with the determination. It showed that this SPR method had good selectivity. The CO content in air samples was determined with the SPR method, with a relative standard deviation (RSD) of 1.8%～4.2%, the SPR method results were agreement with that of the gas chromatography (GC)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2576 (2016)
Study on the Prediction of Cotton Yield within Field Scale with Time Series Hyperspectral Imagery
LIU Huan-jun, KANG Ran, Susan Ustin, ZHANG Xin-le, FU Qiang, SHENG Lei, and SUN Tian-yi
Pixel-based processing method mainly extracts spectral information from hyperspectral remote sensing images, but site specific management zone (SSMZ) delineation and crop yield estimation with images need to take spatiotemporal heterogeneity into account. As the spatial resolution of remote sensing data increases, the Pixel-based processing method mainly extracts spectral information from hyperspectral remote sensing images, but site specific management zone (SSMZ) delineation and crop yield estimation with images need to take spatiotemporal heterogeneity into account. As the spatial resolution of remote sensing data increases, the so-called “salt-and-pepper” problem of pixel-based classification becomes more serious. The spatiotemporal heterogeneity of soil properties and crop biophysical parameters are mainly delineated with grid sampling and geostatistics interpolation, but the widely used method has some problems: time consuming and high cost. Satellite imageries are introduced to delineate SSMZ, but there are also problems needed to be resolved: (1) single date imagery is used to map SSMZ which is difficult to determine the optimal date for SSMZ delineation; (2) only few SSMZs were mapped, which limited application of site specific fertilizing and management; (3) pixel-based method for SSMZ delineation didn't concern the spatial relationship between pixels and site specific management does not implement at pixel level, but at SSMZ level. To improve the accuracy of crop yield estimation, a time-series of hyperspectral airborne images with high spatial resolution (1 m) of a cotton field, which is located in San Joaquin Valley, California US, were acquired and classified by using object-oriented segmentation, then yield predicting models were built, and the accuracy and stability of yield models were validated with determining coefficients R2 and the root mean square error (RMSE). Results are as follows: (1) object-oriented SSMZ delineating method combines spectral, spatial and temporal information, reduces noises in images and yield data, improves the accuracy of yield prediction; (2) for same SSMZ number, first derivative predicting model is more accurate; (3) for same spectral input, models with fewer SSMZs show higher accuracy, which is due to spatial errors of airborne images and yield data. The results will improve monitoring methods for crop growth and yield while accelerate the application of UAV remote sensing in precision agriculture..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2585 (2016)
Pollution Source Identification of Water Body Based on Aqueous Fingerprint-Case Study
L Qing, XU Shi-qin, GU Jun-qiang, WANG Shi-feng, WU Jing, CHENG Cheng, and TANG Jiu-kai
Three-dimensional fluorescence spectroscopy is an emerging sensitive technology to detect organic pollution in water bodies. Based on this technique, a research group from Tsinghua University developed a novel instrument as a tool of pollution early-warning and pollution source identification, it has been put into use Three-dimensional fluorescence spectroscopy is an emerging sensitive technology to detect organic pollution in water bodies. Based on this technique, a research group from Tsinghua University developed a novel instrument as a tool of pollution early-warning and pollution source identification, it has been put into use in A city in South China, for aqueous fingerprint monitoring and pollution sources identification under abnormal conditions. As a new monitoring method, it broke the limitation that traditional water quality monitoring technology could not provide directivity information of pollution source, and could detect abnormity of water quality quickly and identify pollution source accurately. In this paper, the process to identify pollution source during an abnormity incident of water quality in S River captured by the instrument was studied. When the instrument captured unidentified aqueous fingerprints during on-line monitoring, pollution intrusion process was inferred based on the variation of aqueous fingerprint figure and peak intensity. Then the pollution source identification was achieved by comparing the fingerprints between the polluted water body and possible pollution sources by the instrument. The source identification was verified with the changes of other water quality parameters such as pH, aniline, TOC and TN. The results showed that this early-warning and pollution source identification technique can quickly detect and release warning of abnormity of water quality and identify pollution sources accurately via monitoring aqueous fingerprints. The abnormity incident studied in this paper might be caused by dumping raw materials by a chemical plant located in upstream of the river..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2590 (2016)
Egg Freshness Detection Based on Hyper-Spectra
WANG Qiao-hua, ZHOU Kai, WU Lan-lan, and WANG Cai-yun
This research collected the transmission hyper-spectral data of eggs with hyper-spectral imager. Haugh unit value was used as freshness norm. With the help of MATLAB and SAS software combined with stechiometry method, the hyper-spectral data of sample eggs was analyzed and processed. The prediction model of egg freshneThis research collected the transmission hyper-spectral data of eggs with hyper-spectral imager. Haugh unit value was used as freshness norm. With the help of MATLAB and SAS software combined with stechiometry method, the hyper-spectral data of sample eggs was analyzed and processed. The prediction model of egg freshness was established based on hyper-spectral technology. The research chose the band range from 500 to 1 000 nm as sensitive band. The hyper-spectral data of abnormal samples were removed by using mahalanobis distance. Differential correction was done on hyper-spectral data. After the comparison, there was a high linearity between the second-order differential data of hyper-spectra and haugh unit value. Therefore, this paper conducted a further research on the second-order differential data of hyper-spectra. And it was treated with wavelet denoising, smoothing and standardizing. This paper chose the newly proposed CARS variable selection method to do dimensionality reduction on hyper-spectral data. And thirty-two characteristic parameters were extracted. They were used to establish partial least square prediction model based on all band and multiple regression model based on characteristic parameters on white shell eggs. The correlation coefficients of white shell eggs were 0.88 and 0.93 respectively, and the corresponding mean square errors being 7.565 and 6.44. Inspections were conducted on PLS prediction model based on all band hyper-spectral second-order differential and multiple regression model based on characteristic parameters by using eggs of validation set. The accuracy rates of these two models to discriminate white shell eggs’ freshness and non-freshness were 100% and 88% respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2596 (2016)
The Effect of Plasma Spatially Resolved During Diamond Film Deposited with HFCVD
YI Cheng, WANG Chuan-xin, FAN Yong-zhi, DAI Kai, MA Zhi-bin, WANG Sheng-gao, MAN Wei-dong, and WU Chao
Optical emission spectroscopy (OES) was used to detect the plasma distribution during the depositing process of diamond films with hot filament chemical vapor deposition (HFCVD) method using acetone as carbon source. The surface and cross section of deposited diamond films were characterized by scanning electron microsOptical emission spectroscopy (OES) was used to detect the plasma distribution during the depositing process of diamond films with hot filament chemical vapor deposition (HFCVD) method using acetone as carbon source. The surface and cross section of deposited diamond films were characterized by scanning electron microscopy (SEM) and their quality was tested with Raman spectroscopy. OES results showed that the intensity of active species near the center is higher than that in marginal area in the case of linear array of hot filament. It is because of the higher temperature and stronger cracking ability near the filament. The variety of the characteristic peak intensity in central region is more gently than that of the plasma ball. Thermal radiation decreased when the distance from the hot filament increases, which results in less CH, CO groups cracked from acetone, lower intensity of Hα, Hβ excited by hydrogen and higher concentration of C2 group produced by reaction. SEM and Raman results showed that the quality of deposited diamond films deteriorated when the distance between hot filament and substrate varies from 4.5, 5.5 to 6.5 mm, which matches well with OES results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2601 (2016)
A New Calibrated Model of Coal Calorific Value Detection with LIBS
WANG Di, LU Ji-dong, DONG Mei-rong, YAO Shun-chun, FAN Ju, TIAN Zhao-hua, WANG Lei, and LI Shi-shi
A set of coal samples were used for laser-induced breakdown spectroscopy (LIBS) experiment to measure the coal calorific value. Traditional channel normalization method didn't consider the physical / chemical mechanism of coal, which would limit the model in precision, accuracy and repeatability. Thus a new calibraA set of coal samples were used for laser-induced breakdown spectroscopy (LIBS) experiment to measure the coal calorific value. Traditional channel normalization method didn't consider the physical / chemical mechanism of coal, which would limit the model in precision, accuracy and repeatability. Thus a new calibrated model based on the kinds of the effects of spectral deviation was proposed in this paper. The model selected 19 groups of coal samples, where the random 15 groups were used to establish quantitative analysis model of calorific value while the remaining four for inspection and evaluation. The model based on spectral deviation factors, and the transmission theory combined with the stark broadening formula was used to deduce the absorption effect mechanism and the deviation correction method under the condition of LIBS. The mutual interference between elements and the mechanism of matrix effect were being analyzed while K coefficient method was used to correct mutual interference between the elements in the LIBS. The establishment of numerical model with the electron density, the plasma temperature and the element concentration was used to deeply corrected spectrum deviation caused by matrix effect. Thus taking into consideration of the effect of self-absorption, interfere of inter-elements and matrix effect, the calibration model was established, while R2=0.967, RMSEP=0.49 MJ·kg-1, RMSE=0.45 MJ·kg-1, MRE=2.42%, ARE=1.64%, RSD=5.79% and RSDP=8.10%. Compared with the 0.405, 8.28 MJ·kg-1, 4.14 MJ·kg-1, 22.85%, 52.48%, 18.28% and 32.85% of traditional channel normalized-multiple linear regression method, it demonstrated that the precision and accuracy have been improved significantly and model has good application value..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2607 (2016)
Multi-Element Detection in Molten Steel with Laser-Induced Breakdown Spectroscopy
YU Yun-si, PAN Cong-yuan, ZENG Qiang, DU Xue-wei, WEI Shen, WANG Sheng-bo, and WANG Qiu-ping
On-line element content detection in iron and steel industry is one of the key techniques to ensure the quality in iron and steel metallurgy. Laser Induced Breakdown Spectroscopy (LIBS) has been applied to on-line components detection in molten steel. We have built LIBS system for components detection of molten steel iOn-line element content detection in iron and steel industry is one of the key techniques to ensure the quality in iron and steel metallurgy. Laser Induced Breakdown Spectroscopy (LIBS) has been applied to on-line components detection in molten steel. We have built LIBS system for components detection of molten steel in laboratory. The system consists of a Q-switched Nd∶YAG laser (repetition rate 10 Hz, wavelength 1 064 nm, pulse length 10 ns, pulse energy about 120 mJ), high frequency induction furnace (temperature 1 600 ℃), spectrometer (wavelength range 186～310 nm, spectral resolution 0.1 nm), laser focusing and spectral signal collecting system. Multi-elements were detected in molten steel with the application of deep-UV detector coating and solarization resistant fibers. According to the calibration curves of C, S, Mn and Cr, the limit of detections are 169, 15, 58.9 and 210 μg·g-1 respectively. The R-squares of calibration curves of C, S, Mn, and Cr are better than 0.96 by using appropriate analytical lines and reference lines. At the same time, through the comparison of different elements, we find the best calibration curve of different element need different delay conditions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2613 (2016)
The Detection of Heavy Metals in Soil with Laser Induced Breakdown Spectroscopy
YUAN Di, GAO Xun, YAO Shuang, and ZHENG Bao-luo
The elemental concentration of Cr contained in soil is measured with laser induced breakdown spectroscopy (LIBS). As the LIBS laser power, the laser wavelength is of 1 064 nm with pulse width of 8 ns and laser repetition frequency of 10 Hz in this experiment and Cr 427.4 nm is selected as the analytical line of LIBS. TThe elemental concentration of Cr contained in soil is measured with laser induced breakdown spectroscopy (LIBS). As the LIBS laser power, the laser wavelength is of 1 064 nm with pulse width of 8 ns and laser repetition frequency of 10 Hz in this experiment and Cr 427.4 nm is selected as the analytical line of LIBS. The experimental results show that the relative standard deviation (RSD) of the detected content of Cr is 12.1% at the delay time of 4.78 μs and the soil sample surface 1 mm behind lens focal point. The limit of detection (LOD) of LIBS is 2.01 ppm. The measured relative deviation between the measured value and the nature value is 5.15%. Because the LIBS has advantages such as lower LOD and higher detection precision, LIBS has a guiding significance to detect heavy metal in soil and to monitor environmental quality precisely and rapidly..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2617 (2016)
Determination of Trace Impurity Elements in Food Grade Chitosan with Inductively Coupled Plasma Mass Spectrometry
NIE Xi-du, and FU Liang
A method of inductively coupled plasma mass spectrometry (ICP-MS) was established to determinate trace impurity elements in chitosan. After dissolving in 3% citric acid and low concentration of HCl, the elements including Be, B, Na, Mg, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sn, Sb, Hg and Pb in chitosan A method of inductively coupled plasma mass spectrometry (ICP-MS) was established to determinate trace impurity elements in chitosan. After dissolving in 3% citric acid and low concentration of HCl, the elements including Be, B, Na, Mg, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Sn, Sb, Hg and Pb in chitosan were measured with ICP-MS directly. The addition of low concentration of HCl could effectively improve the stability of all elements, especially Hg and Sn. Dynamic reaction cell (DRC) was used to correct the interference of chlorine ion and other mass spectral interference. The matrix matching and the internal standard elements mixed solution (Sc, Y, In and Bi) had compensated the difference of sample transfer efficiency and evaporation rate of organic solvent. Under the optimum condition, the standard curve of each element exhibits linear correlation coefficient was not less than 0.999 7. The detection limit of the 20 elements was in the range of 0.6～19.0 ng·L-1 while the recovery of standard addition was 89.50%～109.00% with RSD 1.17%～4.05%. The practical sample analysis results showed that the content of impurities in food grade chitosan is very low. And the heavy metal content is extremely low and safe to eat. This method is very simple, sensitive and accurate for the determination of 20 impurity elements in the food grade chitosan..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2621 (2016)
Determination of Lead and Cadmium in Calendula Officinalis Seedlings for Phytoremediation of Multi-Contaminated Loess by Using Flame Atomic Absorption Spectrometry with Wet Digestion
FAN Chun-hui, DU Bo, ZHANG Ying-chao, GAO Ya-lin, and CHANG Min
Atomic absorption spectrometry (AAS) is widely used in the analysis and detection of heavy metals. The optimal operation conditions on metals detection are important for the stabilization and repeatability of scientific research, which affects the expected investigation objectives greatly. Thus, it becomes a key issue Atomic absorption spectrometry (AAS) is widely used in the analysis and detection of heavy metals. The optimal operation conditions on metals detection are important for the stabilization and repeatability of scientific research, which affects the expected investigation objectives greatly. Thus, it becomes a key issue to establish appropriate detection methods in scientific works. Calendula officinalis was used for lead/cadmium remediation in contaminated loess, and the flame atomic absorption spectrometry (FAAS) with wet digestion was applied to analyze the contents of lead/cadmium in Calendula officinalis seedlings. The investigation data was further studied to reveal the bioaccumulation efficiency of lead/cadmium in Calendula officinalis seedlings. The results showed: the limits of detection are 0.104 and 0.007 mg·L-1 for lead and cadmium; the recovery rates of lead and cadmium are from 94.33% to 110.78% and 97.73% to 107.50% respectively. The relative standard deviations (RSD) are between 4.11% and 4.75% for lead while between 1.11% and 2.77% for cadmium, and It’s been proved that the method is accurate and reliable. The low accumulation efficiency of lead with Calendula officinalis seedlings might be related to the electronegativity of lead while the growth period of calendula officinalis seedlings and environmental factors. The accumulation content of cadmium is 104.85 mg·kg-1 with cadmium concentration of 50 mg·kg-1. The co-existing of lead in loess is positive for cadmium accumulation by Calendula officinalis seedlings, and the synergistic effect might work in the process. The established detection method is effective for quantitative analysis of lead and cadmium in calendula officinalis seedlings and significant for future research..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2625 (2016)
The Gemological Characteristics of One Kind Turquoise Imitation
CHEN Quan-li, AI Su-jie, WANG Qian-xiang, LIU Xian-yu, DING Xin-rong, and YIN Zuo-wei
It has been a long time that the imitations of turquoise appear in gem market. Pressed dyed carbonate in the early stage and dyed variscite, chalcedony as well as magnesite appeared in succession. These kinds of materials do not have the color and characteristics of natural turquoise. Their physical and optical propertIt has been a long time that the imitations of turquoise appear in gem market. Pressed dyed carbonate in the early stage and dyed variscite, chalcedony as well as magnesite appeared in succession. These kinds of materials do not have the color and characteristics of natural turquoise. Their physical and optical properties are quite different from natural turquoise. One kind of turquoise imitation newly appears in market is selected to be studied in this paper. The conventional gemological method, infrared absorption spectroscopy and X-ray diffraction were employed to study its mineral compositions, gemological properties and structural characteristics. The results show that: the brecciated structure can be observed and the distribution of the iron wire is very simple on the surface of the sample. Deep blue granules are visible on the surface of blue samples and a few black spots can be observed on the surface of white ones, which are typical indication of pressing process. The blue imitations of turquoise has been stained and pressed. The index of this kind of turquoise imitation range from 1.54 to 1.58, which is lower than that of natural turquoise and it show bluish white fluorescence, which can be used as important evidence to distinguish it with natural turquoise. The data of X-ray diffraction shows the sample mainly consists of enstatite and quartz. The results of infrared absorption spectroscopy show that the absorption spectra of this kind of turquoise imitation is in accordance with the typical absorption peaks of enstatite: the absorption peaks which locates near 1 088 and 799 cm-1 are associated with Si—O, Si—O—Si stretching vibration in quartz; the absorption peaks near 2 947 and 2 882 cm-1 is related with stretching vibration of CH2 of exotic organic resin; the absorption peaks near 1 736 and 1 510 cm-1 are resulted from the bending and stretching vibration of CO and CH2..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2629 (2016)
Diffuse Reflectance Spectroscopy of Red Colored “Laowo Stone”
HAN Wen, KE Jie, CHEN Hua, LU Tai-jin, and YIN Ke
In recent years, a kind of new seal stone called “Laowo Stone” from Laos has entered the Chinese seal stone market and it has great impact on the market. However the coloration mechanism is unclear. In order to study the coloration mechanism of “Laowo Stone”, red samples were investigated with VIS DRS techniques togethIn recent years, a kind of new seal stone called “Laowo Stone” from Laos has entered the Chinese seal stone market and it has great impact on the market. However the coloration mechanism is unclear. In order to study the coloration mechanism of “Laowo Stone”, red samples were investigated with VIS DRS techniques together with XRD, FTIR and EDXRF. It was found that: the main mineral composition of “Laowo Stone” is dickite, together with small amounts of kaolinite. EDXRF data show that the concentration of the red color has a good relationship with Fe element; the spot with deeper color has higher Fe content. Fe occurs as iron mineral distributed in the dickite particles. The grain size of the muddy iron minerals is extremely small and the content is low, regular micro area study cannot identify the iron mineral. Then we study the samples with diffuse reflectance spectroscopy (DRS) which is sensitive to iron minerals. The derivative curves of DRS are potentially useful for quantitatively determining hematite and goethite concentration in soils. The main mineral composition of “Laowo Stone” is clay mineral, which is the same as soils. So DRS is used to identify the iron minerals. The first order derivative spectrum has the 565~570 nm peak and the iron mineral was identified to be hematite. Our results confirmed that the red coloration of “Laowo Stone” is caused by tiny hematite crystals distributed within the grain boundaries of dickite particles..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2634 (2016)
Study on Orbit Radiometric Calibration for FY-2 Visible Band based on Deep Convective Cloud
CHEN Lin, XU Na, HU Xiu-qing, LU Feng, and ZHANG Peng
A radiometric calibration method is described in this paper by using the deep convective clouds (Deep Convective Cloud, DCC) target for FY-2 visible channel. The deep convective cloud can be used as the radiometric calibration transfer object. The on-operational FY-2 radiometric calibration bias and the long-term degraA radiometric calibration method is described in this paper by using the deep convective clouds (Deep Convective Cloud, DCC) target for FY-2 visible channel. The deep convective cloud can be used as the radiometric calibration transfer object. The on-operational FY-2 radiometric calibration bias and the long-term degradation trend are evaluated according to the AQUA/MODIS instrument as the baseline of radiometric reference and DCC. The results show that: (1) There are different degrees of degradation for FY-2D, FY-2E and FY-2F, among which FY-2D has the biggest degradation due to the longest period. The annual rates of degradation for FY-2D and FY-2E are quite similar, 1.67% and 1.69% respectively, whereas the rate for FY-2F is lower with 0.81%; (2) During the period of satellite eclipse, the instruments are not stable and this phenomenon could be detected by the DCC method; (3) There are bias in the the operational radiometric calibration between FY-2 and AQUA/MODIS, which is treated as the the radiometric reference usually. The radiometric calibration method based on DCC could work well in the radiometric calibration for FY-2. The results will help us to understand the degradation of instrument and for quantitative application usage..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2639 (2016)
Research on the Clustering of Massive Stellar Spectra Based on Line Index
WANG Guang-pei, PAN Jing-chang, YI Zhen-ping, WEI Peng, and JIANG Bin
Clustering algorithm is an important algorithm used to find the data distribution and implicit scheme in data mining. It can study spectra of large amount, multi-parameter and categories unknown simply and effectively. Using lick index as the eigenvalues of spectra can effectively improve the speed to calculate the higClustering algorithm is an important algorithm used to find the data distribution and implicit scheme in data mining. It can study spectra of large amount, multi-parameter and categories unknown simply and effectively. Using lick index as the eigenvalues of spectra can effectively improve the speed to calculate the high-dimensional spectra which can also retain more astrophysical characteristics of spectra. This paper finishes clustering of the survey data with k-means algorithm, using lick index as the eigenvalues of data with finished analysis results. The results show that the new method can gather data with similar physical characteristics together quicker and efficiently, with very good results in discovering rare stars. This method can be applied to the study of Survey data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2646 (2016)
A Method of Stellar Spectral Classification Based on Map/Reduce Distributed Computing
PAN Jing-chang, WANG Jie, JIANG Bin, LUO A-li, WEI Peng, and ZHENG Qiang
Celestial spectrum contains a great deal of astrophysical information. Through the analysis of spectra, people can get the physical information of celestial bodies, as well as their chemical composition and atmospheric parameters. With the implementation of LAMOST, SDSS telescopes and other large-scale surveys, massiveCelestial spectrum contains a great deal of astrophysical information. Through the analysis of spectra, people can get the physical information of celestial bodies, as well as their chemical composition and atmospheric parameters. With the implementation of LAMOST, SDSS telescopes and other large-scale surveys, massive spectral data will be produced, especially along with the formal operation of LAMOST, 2 000 to 4 000 spectral data will be generated each observation night. It requires more efficient processing technology to cope with such massive spectra. Automatic classification of stellar spectra is a basic content of spectral processing. The main purpose of this paper is to research the automatic classification of massive stellar spectra. The Lick index is a set of standard indices defined in astronomical spectra to describe the spectral intensity of spectral lines, which represent the physical characteristics of spectra. Lick index is a relatively wide spectral characteristics, each line index is named after the most prominent absorption line. In this paper, the Bayesian method is used to classify stellar spectra based on Lick line index, which divides stellar spectra to three subtypes: F, G, K. First of all, Lick line index of spectra is calculated as the characteristic vector of spectra, and then Bayesian method is used to classify these spectra. For massive spectra, the computation of Lick indices and the spectral classification using Bayesian decision method are implemented on Hadoop. With use of the high throughput and good fault tolerance of HDFS, combined with the advantages of MapReduce parallel programming model, the efficiency of analysis and processing for massive spectral data have been improved significantly. The main innovative contributions of this thesis are as follows. (1) Using Lick indices as the characteristic to classify stellar spectra based on Bayesian decision method. (2) Implementing parallel computation of Lick indices and parallel classification of stellar spectra using Bayesian based on Hadoop MapReduce distributed computing framework..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2651 (2016)
Stokes Parameter Detection and Precision Analysis Based on Rotating Quarter-Wave Plate
ZHI Dan-dan, LI Jian-jun, GAO Dong-yang, YUAN Yin-lin, ZHAI Wen-chao, PANG Wei-wei, and ZHENG Xiao-bing
The accuracy of the calibration reference source polarization states directly influences the precision of the polarized optical remote sensor calibration, and thus affects the inversion accuracy of the characteristics of targets. In this paper, 870 nm horizontal linear polarized light has been chosen as the tested caliThe accuracy of the calibration reference source polarization states directly influences the precision of the polarized optical remote sensor calibration, and thus affects the inversion accuracy of the characteristics of targets. In this paper, 870 nm horizontal linear polarized light has been chosen as the tested calibration reference light, modulated by rotating quarter-wave plate(QWP). The intensity as a Fourier series of the rotation angle of the plate and its coefficients were demodulated with the Fourier transform method, Stokes parameters can be calculated with these coefficients. The mean, standard deviation, composite uncertainty and relative deviation of measured data compared with the theoretical value of the ten measurement results were presented. In order to improve the accuracy of the measurement, the correction model for the quarter-wave plate retardance deviation Δδ, fast axis angle deviation Δα and the transmission axis alignment deviation Δβ of analyzing polarizer has been constructed. In this model, detection deviation of Stokes parameters is described as a function of Δδ and Δβ, Δδ and Δβ were determined by the function and magnitude of the deviation. Combined with quarter-wave plate fast axis angle deviation which was the result of simulation to adjust the experiment device, and then detecting the calibration reference source polarization states again. The experimental results show that, the difference between measured value and theoretical value of Stokes parameters reduced to less than 1.41% from 3.77% relative to without correction. The experiment principle, device and deviation correction model of this research can significantly improve the accuracy of detecting the polarization state of the calibration reference light source..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2655 (2016)
The Research and Application of Transient Temperature Test Based on Apodized-Chirped FBG
WANG Gao, QI Le-rong, LIU Zhi-chao, LIU Zhi-ming, ZHENG Guang-jin, and WU Jing-zhi
In order to quickly and accurately obtain the transient temperature field information of the barrel when the gun is firing, the transient temperature measurement system was designed with apodized-chirped fiber Bragg grating (FBG) probe. In the system, chirped fiber grating was used to modulate the bandwidth of echo ligIn order to quickly and accurately obtain the transient temperature field information of the barrel when the gun is firing, the transient temperature measurement system was designed with apodized-chirped fiber Bragg grating (FBG) probe. In the system, chirped fiber grating was used to modulate the bandwidth of echo light. The bandwidth of echo light had been greatly improved. So the number of apodized-chirped FBGs in one fiber could be greatly increased, and the energy of echo light was increased too. The performances of five common apodization functions were analyzed, and the super-Gaussian function was used to process the echo signals in the system. This function effectively suppressed sidelobe increases and spectral dispersion caused by chirp modulation, which indicated that it could meet the design requirements of the transient temperature measurement. 50 apodized-chirped FBGs, which evenly wound on the barrel, were used in the experiments, and they modulation range was from 1 532.0 to 1 548.0 nm. Transient temperature of a certain type of gun barrel was tested when it fired, and test data from the system were compared to WRP-130S high-speed temperature detector. Experimental results show that the two methods are similar ones with average error of less than 2%, and better than 1% in the region of temperature steady drop. 1 ℃ can cause 0.041 3 nm wavelength shift in temperature-wavelength data. Transient temperatures of 50 independent positions can be obtained in an acquisition, so the efficiency of the barrel temperature field reconstruction is greatly improving..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2660 (2016)
The Study of Precision Measurement Technology Based on AOTF Imaging Spectrum
XUE Peng, WANG Zhi-bin, ZHANG Rui, XUE Rui, and ZHAO Tong-lin
Acousto-Optic Tunable Filter as a new beam splitting elements of spectral imaging. We often regard the diffraction center wavelength which is corresponded with the incident light perpendicular to the incident plane of AOTF as the wavelength of CCD spectral measurement. However, the different positions of target have diAcousto-Optic Tunable Filter as a new beam splitting elements of spectral imaging. We often regard the diffraction center wavelength which is corresponded with the incident light perpendicular to the incident plane of AOTF as the wavelength of CCD spectral measurement. However, the different positions of target have different incident angles when the incident light enter into the AOTF, which will cause error when the CCD actual spectral measurement is compared with the spectral measurement of vertical incidence. The characteristics of this system we have used is that the target light imaging on the focal plane of CCD by passing the pre optical system, AOTF and the imaging lens, which have achieved the goal that the target light imaging on the whole system only once. Compared with the system of secondary imaging, the system of first imaging can improve the quality of image and the light energy utilization ratio. Because of the field angle of AOTF is ±3°, we analyzed the regular pattern of the diffraction wavelength changing with angle of incidence and obtained the revised spectrum measurement equation by processing the real measured value of diffraction wavelength changing with angle of incidence. The experimental results show that its relative error can be reduced an order of magnitude by using the revised equation to measure the spectrum. This method can lay the foundation for improving the measurement accuracy of AOTF imaging spectral in the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2664 (2016)
The Development of Ammonia Sensor Based on Tunable Diode Laser Absorption Spectroscopy with Hollow Waveguide
DU Zhen-hui, ZHANG Zhe-yuan, LI Jin-yi, XIONG Bo, and ZHEN Wei-meng
Hollow waveguides（HWG）have recently emerged as a novel concept serving as an efficient optical waveguide and a highly miniaturized gas cell. Compared with conventional multi-pass gas cells, HWG gas cell has the advantages of facilitating gas exchanging because of its small size and fast responding speed. In this paper,Hollow waveguides（HWG）have recently emerged as a novel concept serving as an efficient optical waveguide and a highly miniaturized gas cell. Compared with conventional multi-pass gas cells, HWG gas cell has the advantages of facilitating gas exchanging because of its small size and fast responding speed. In this paper, we poposed an ammonia sensor based on tunable diode laser absorption spectroscopy(TDLAS) using HWG as the gas cell. The sensor employs wavelength modulation spectrum(WMS) with simultaneous detection of the second harmonic(2f) signal and the first hamonic(1f) signal. Normalization of the 2f signal by the 1f signal enables the sensor for calibration free measurement. The sensor performance is tested with gas standards and the result shows good linearity with correlation coefficient of 0.999 8, and the detection limit is 26 ppb with an integration time of 18 s. The sensor based on HWG gas cell is suitable for sensative and real-time monitoring ammonia in the air..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2669 (2016)
Study on the Spectral Characteristics of Xeon Flash Lamp and Experimental Measurement
ZHAI Rui-wei, ZHAO You-quan, MIAO Pei-liang, JIANG Nan, JIANG Lei, LIU Xiao, and XU Qiao-yan
Xenon flash lamp is used by most analytical instruments and medical equipments as light sources whose spectral characteristics exert a tremendous influence on the property of instruments and medical equipments. In order to study the effects of pulsed Xenon discharge circuit parameters and geometric parameters on the spXenon flash lamp is used by most analytical instruments and medical equipments as light sources whose spectral characteristics exert a tremendous influence on the property of instruments and medical equipments. In order to study the effects of pulsed Xenon discharge circuit parameters and geometric parameters on the spectral characteristics, theoretical analysis has been conducted to Xenon lamp emitting process with the gas discharge theory. The spectroscopic detection system has been designed to conduct experimental detection to the spectral characteristics of pulsed Xenon lamp with different parameters. The experimental results show that the emission spectra of Xenon flash lamp contain both line and continuous radiation. The line spectrum results from the electron energy gap transition, while the cw radiation related to ionic recombination and bremsstrahlung. The relative spectral intensity increases linearly with the discharge voltage, and has a positive correlation with storage capacitor. When low discharge voltage, the shorter the arc length, the higher the relative spectral intensity .while the discharge voltage becomes higher, the result is reversed. The work in this paper has great significance for xenon flashlamp on the parameters selection and industrial application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2674 (2016)
SOHO/SUMER Observations of Transition Region Explosive Events in Prominence
ZHANG Min, WANG Dong, and DENG Yan
Explosive events (EEs) are small-scale dynamic phenomena often observed in the solar transition region (TR). EEs are characterized by non-Gaussian and broad profiles with enhancements in the blue/red wings with an average line-of-sight Doppler velocities of ～100 km·s-1. They have a small spatial scale of about 1 8Explosive events (EEs) are small-scale dynamic phenomena often observed in the solar transition region (TR). EEs are characterized by non-Gaussian and broad profiles with enhancements in the blue/red wings with an average line-of-sight Doppler velocities of ～100 km·s-1. They have a small spatial scale of about 1 800 km and a short lifetime of about 60 s on average. EEs are often found to be associated with magnetic cancellation and reveal bi-directional flows with high velocities comparable to the local Alfvén velocity; they are generally regarded as the consequence of small-scale fast magnetic reconnections. Since the launch of SOHO spacecraft, the SUMER (solar ultraviolet measurements of emitted radiation) spectrograph has been widely used to study EEs. With high spatial and spectral resolution, and wide spectral coverage, SUMER was a powerful tool of ultraviolet spectroscopy and it has greatly increased our knowledge of EEs. Relationship between EEs and other small-scale events observed in the transition region, such as blinkers and EUV spicules have also been investigated during the SOHO era. However, the association between EEs and large-scale events such as prominence remains unclear. A sit-and-stare mode observation made by SUMER is selected for the study. We investigate the properties of EEs in a prominence. EEs are identified with analysis of the width of Si Ⅲ line (111.3 nm). The Si Ⅲ lines with a width greater than three standard deviations (3σ) were singled out for further visual inspection to finally determine the occurrence of EEs. It is found that the vast majority of explosive events concentrate in the bright knots of the prominence. EEs in the core of the prominence occur repetitively with a period of about 20 mins. It is proposed that the explosive events caused by small-scale fast magnetic reconnections are triggered by magnetic flux loops in the core of prominence. The blue shift of the explosive events is significant and possibly related to the initiation of a CME..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2679 (2016)
Spectroscopic Properties of Energy Transfer Effect in Sm3+/Eu3+ Doped LaF3 Nanocrystals
FU Zhen-xing, LIU Bi-rui, and YANG Bing-xiong
The samples of LaF3∶Sm3+, LaF3∶Eu3+ and LaF3∶Sm3+/Eu3+nanocrystals with high quality mono-disperse and uniform sizes were synthesized with hydrothermal method. The crystallographic phase, surface morphology, crystalline sizes and fluorescence properties of Sm3+/Eu3+ sole- and co-doped nanocrystals were characterized wiThe samples of LaF3∶Sm3+, LaF3∶Eu3+ and LaF3∶Sm3+/Eu3+nanocrystals with high quality mono-disperse and uniform sizes were synthesized with hydrothermal method. The crystallographic phase, surface morphology, crystalline sizes and fluorescence properties of Sm3+/Eu3+ sole- and co-doped nanocrystals were characterized with X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopic technique, respectively. The results of XRD and TEM show that the microstructure of the nanocrystals is hexagonal, with the average size about 40 nm. Using 442 nm He-Cd continuous wave (CW) laser to pump the Sm3+ ions doped in the LaF3∶Sm3+/Eu3+nanocrystals, the typical fluorescence emissions originating from the Eu3+ions were observed in the emission spectra, and that the energy transfer from Sm3+ions to Eu3+ions was completed. The mechanism and efficiency of the energy transfer from Sm3+ions to Eu3+ ions were investigated and discussed systematically based on the spectroscopic method. It is shown that the energy transfer of Sm3+→Eu3+ is attributed to the cross-relaxation between the excited state 4G5/2 of Sm3+ ion and the 5D1 and 5D0 states of Eu3+ ion. Meanwhile, the intensities of the characteristic fluorescence emissions of Eu3+ ions become stronger and stronger with the increase of the Eu3+ doping concentration, which suggest that the efficiency of energy transfer from Sm3+ ions to Eu3+ ions can be effectively improved by increasing the doping concentration of Eu3+ acceptor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2686 (2016)
Study on the Detection of Rice Seed Germination Rate Based on Infrared Thermal Imaging Technology Combined with Generalized Regression Neural Network
FANG Wen-hui, LU Wei, XU Hong-li, HONG De-lin, and LIANG Kun
On the basis of the differences in physiology and physics of rice seed with different aging time, the paper proposes a fast and nondestructive method which is based on infrared thermal imaging technology and generalized regression neural network to detect the germination rate of rice seed. This method solves the probleOn the basis of the differences in physiology and physics of rice seed with different aging time, the paper proposes a fast and nondestructive method which is based on infrared thermal imaging technology and generalized regression neural network to detect the germination rate of rice seed. This method solves the problems of long experimental period, complex operations and other disadvantages of the traditional method which is used to detect germination rate. When the temperature is 45 ℃ and humidity is 90%, the rice seeds are aged for 0, 1, 2, 3, 4, 5, 6 and 7 d respectively to get rice seeds of different germination rate. The data of 144 groups was extracted from the germ of rice seed. This data was divided into two groups randomly: the calibration set was 96 groups and the prediction set was 48 groups. Through analyzing and comparing the differences of infrared thermal image of rice seeds of different aging days, the relationship in physics and physiology between germination rate of rice seed and infrared thermal images was revealed. The infrared prediction model for germination rate of rice seed was established by combining partial least squares algorithm, Back Propagationneural network and General regression neural network. The result shows that the optimal germination rate model is built with GRNN. In this model, the correlation coefficient (RC) and standard deviation (SEC) of calibration sets are 0.932 0 and 2.056 0. At the same time, the correlation coefficient (RP) and standard deviation (SEP) of prediction sets are 0.900 3 and 4.101 2. The relevance reaches a higher level and the standard deviation is small. Therefore, the experiment shows that combining infrared thermal imaging technology with GRNN to study germination rate of rice seed is feasible. The model has a higher accuracy in terms of rapid determination of the germination rate of rice seed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2692 (2016)
A New Strategy to Probe and Compare the Binding Modes of Two Perfluorocarboxylic Acids with Human Serum Albumin Based on Spectroscopic and Molecular Docking Methods
HU Tao-ying, FANG Qing, JIN Ye, ZHOU Shan-shan, and LIU Ying
Perfluorocarboxylic acids (PFCAs) have been widespread used for over half century as surfactants in commercial and industrial products because of their hydrophilic and hydrophobic peculiarity. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) are two representatives of long-chain PFCAs, and they wPerfluorocarboxylic acids (PFCAs) have been widespread used for over half century as surfactants in commercial and industrial products because of their hydrophilic and hydrophobic peculiarity. Perfluoroundecanoic acid (PFUnA) and perfluorotridecanoic acid (PFTriA) are two representatives of long-chain PFCAs, and they were detected more frequently in human body recent years, however, the two PFCAs were found to express endocrine disruption effects, developmental toxicity and teratogenicity. In this study, we established a new strategy to probe the binding modes of PFUnA (PFTriA) with the most abundant protein human serum albumin (HSA) based on spectroscopic and molecular docking methods. Results showed that both PFUnA and PFTriA can quench the intrinsic fluorescence of HSA with one binding site by means of dynamic and static quenching procedure with a strong affinity and the order is PFUnA>PFTriA. On the basis of thermodynamic results, we knew that the main driving force of the interaction between PFUnA and HSA was electrostatic force (ΔH=-26.32 kJ·mol-1, ΔS=21.76 J·mol-1·K-1), while van der Waals interaction and halogen-bond played major roles in complexation process of PFTriA-HSA (ΔH=-39.69 kJ·mol-1, ΔS=-25.66 J·mol-1·K-1). The binding distance (r<8 nm) indicated that the non-radioactive energy transfer came into being from HSA to PFUnA (PFTriA). The binding process of PFUnA (PFTriA) with HSA caused conformational and some micro-environmental changes of HSA, but also led to a loss of helical stability through three-dimensional fluorescence and circular dichroism spectra (CD). Furthermore, site markers competitive experiments and molecular docking revealed that PFUnA and PFTriA had a high affinity into hydrophobic pocket of subdomain IIA in HSA through polar force, hydrophobic interaction and halogen-bond and so on, and the fluorophore Trp residues was located in the binding position which proved further the quenching of PFUnA and PFTriA on HSA fluorescence. The accurate and full basic data in the work are beneficial to clarify the binding mechanism of long-chain perfluorocarboxylic acids with serum protein in vivo, and provide essential theoretical clues for their toxicity assessment and toxicologic research..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2698 (2016)
MA Xiao-ling,DENG Feng-yu,LIU Ying
MA Xiao-ling, DENG Feng-yu, and LIU Ying
Spatial distribution, seasonal variations and pollution conditions of 6 heavy metals (Cr, Pb, Cd, Cu, Zn and Ni) in sediments in three different seasons (wet, dry and normal) from Gansu province, Ningxia and Inner Mongolia Autonomous Regions of the Yellow River were studied using high resolution inductively coupled plaSpatial distribution, seasonal variations and pollution conditions of 6 heavy metals (Cr, Pb, Cd, Cu, Zn and Ni) in sediments in three different seasons (wet, dry and normal) from Gansu province, Ningxia and Inner Mongolia Autonomous Regions of the Yellow River were studied using high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS), geo-accumulation index (Igeo), respectively. The results indicated that content of heavy metals in all three seasons of Inner Mongolia sediment samples were higher compared to Ningxia and Gansu sections, and except Cd, the other metals concentrations in wet season are relatively higher, and they are lower and approximated in dry and normal seasons. Igeo showed that high Igeo values of Cd, Cu and Cr were found in Inner Mongolia region in wet and dry seasons, and the low Igeo values of the three metals were obtained in Gansu region. For season, the Igeo values of all study metals were higher in wet season than dry season, and they were decreased in normal season except Cd, while ICdgeo were high in all sampling sites in normal season indicating the strong anthropogenic sources there. Igeo values of metals including Pb, Zn and Ni were below 0 in wet season of Gansu, in dry season of Gansu, Ningxia regions and in normal season of all study regions, respectively, indicating a safer level. The results of spatial distribution and Igeo of study heavy metals suggested that higher total metal concentrations and potential risks were found in Inner Mongolia reaches of the Yellow River, and Cr, Cd and Cu were being more significant with the strong anthropogenic sources among all study metals. Considering the three different seasons, except normal season, the higher metal concentrations and potential risks for metals in sediments were observed in wet season than dry season, since the higher pH values of the sedimentary samples in wet season can help to promote adsorption and precipitation of heavy metal in sediments, meanwhile, the higher total organic carbon (TOC) values in sediments in wet season were also beneficial to the adsorption of heavy metals since the affinity between TOC and metal cations. Besides, the coast sediments with variety pollutants were brought into the river by rainfall in summer, which may also contribute to the rapid enrichment of heavy metals in sediments in wet season than dry season. The correlation among heavy metals and other variables and potential sources for heavy metals were evaluated by correlation coefficient analysis (CCA). The results of CCA revealed that Pb, Cu, Zn and Ni showed a significant correlation with each other, and they would be easily influenced by pH and TOC. Furthermore, Cr showed a correlation with Cd and TOC and reflected a strong anthropogenic source. The present work could provide new information on the metals behavior in surface sediments and reflect the sediment geochemistry in the regions in the three seasons, whilst the study of element interrelationships, including pH and TOC gave the available information on their possible origins..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2705 (2016)
A Novel Method to Monitor Coal Fires Based on Multi-Spectral Landsat Images
XIA Qing, and HU Zhen-qi
Coal fires pose a serious threat to the environment worldwide, and they are responsible for atmospheric pollution, water contamination, land subsidence and the safety of miners. The multi-spectral Landsat images offer the possibility of detecting and monitoring coal fires at large scales. In this study, the thermal infCoal fires pose a serious threat to the environment worldwide, and they are responsible for atmospheric pollution, water contamination, land subsidence and the safety of miners. The multi-spectral Landsat images offer the possibility of detecting and monitoring coal fires at large scales. In this study, the thermal infrared spectral is extracted, and a mono-window algorithm is used for retrieving coal fire temperature. However, the surface emissivity and atmospheric water vapor content play important roles in determining the temperature for this algorithm. The surface emissivity is particularly difficult to obtain with satellite overpasses because it is affected by a variety of factors. In general, an average emissivity value is assigned to represent all land cover categories, which leads to a big error for retrieving coal fire temperature. Meanwhile, atmospheric water vapor content is calculated by simulating atmospheric profile through standard atmosphere models. However, it is difficult to obtain real water vapor content and atmospheric profile is affected by many factors with each satellite pass. The lack of knowledge of the real atmospheric profile is a large constraint, and inaccurate simulation can introduce big errors. Aiming at overcoming drawbacks mentioned above and increasing the accuracy for this algorithm, the NDVI threshold method is applied to estimate surface emissivity. The NDVI threshold method separates different land cover categories, and different emissivity is assigned to different land cover classifications. Based on the ground meteorological parameters' relationship between atmospheric water vapor and atmospheric water vapor pressure, an empirical relationship is found to estimate atmospheric water vapor content. For this method, the ground meteorological parameters are easily obtained from meteorological observation stations and it is convenient to estimate water vapor content. The mono-window algorithm is improved and coal fire temperature is retrieved. This methodology was applied to the Wuda coalfield, in China, and coal fire temperatures were retrieved and extracted from the background from 1988 to 2015 in the study area. A thorough inventory of coal fire areas and locations is annually presented, and area changes are qualitatively analyzed during the observation period. This method is considered as feasible and effective for retrieving and monitoring coal fires based on multi-spectral Landsat images in comparison to other techniques in the Wuda coalfield, China..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2712 (2016)
Natural Bond Orbitals (NBO), Natural Population Analysis, Mulliken Analysis of Atomic Charges of L-Alaninium Oxalate
C. Charanya, S. Sampathkrishnan, and N. Balamurugan
The Fourier Transform Infrared and Raman spectra of the L-Alaninium oxalate (LAO) have been recorded and analyzed. The fundamental vibrational wave numbers intensities of vibrational bands and optimized geometrical parameters of the compound were evaluated using DFT (B3LYP) method with 6-31+G(d,p) basis set. Natural BoThe Fourier Transform Infrared and Raman spectra of the L-Alaninium oxalate (LAO) have been recorded and analyzed. The fundamental vibrational wave numbers intensities of vibrational bands and optimized geometrical parameters of the compound were evaluated using DFT (B3LYP) method with 6-31+G(d,p) basis set. Natural Bond Orbital (NBO) and Natural Population Analysis (NPA) analysis for the LAO compound was carried out. Mulliken population analyses on atomic charges were also calculated..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2721 (2016)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 1 (2016)
Research Articles
The Latest Research Progress of Coupling between BiOX and Semiconductor Photocatalyst
Cui Yumin, Li Huiquan, Miao Hui, Tao Dongliang, and Fan Suhua
The heterojunction was formed between two kinds of coupling semiconductors , which improved the charge separation efficiency of system, widened the spectral response range of catalysts and improved photocatalytic propertirs of catalysts. The process of preparation of semiconductors coupling was easily affected by prepaThe heterojunction was formed between two kinds of coupling semiconductors , which improved the charge separation efficiency of system, widened the spectral response range of catalysts and improved photocatalytic propertirs of catalysts. The process of preparation of semiconductors coupling was easily affected by preparation methods and reaction temperature and so on, which would cause the changes in crystal structure and surface properties of coupling semiconductors, thus photocatalytic quantum efficiency of coupling semiconductors was increased. In this article, the following three aspects were mainly discussed. (1) About the coupled system of halogen bismuth oxide and oxide, because generaling BiOX with the semiconductor material compound, the efficient heterojunction structure could be formed, photocatalytic performances of the photocatalytic degradation of pollutants were improved. (2) About the coupled system of AgX and BiOX, compared with the pure AgI or BiOI, composite photocatalytic materials of AgI/BiOI had higher photocatalytic reactivity in visible light. (3) About the coupled system of halogen bismuth oxide and other compounds, after Bi2S3 coupled with BiOX, photoproduction electronic migrated in the two kinds of catalysts, the separation efficiency of electrons and holes was improved, and photocatalytic performances of coupling compound were improved. In addition, in recent years, the latest research progress of the preparation method, the influencing factors of the photocatalytic performance and improving the utilization efficiency of visible light of semiconductors coupling at home and abroad was reviewed in this paper. Finally, the main problems and the future striving direction in semiconductors coupling were presented..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 8, 2579 (2016)
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