Journals >Spectroscopy and Spectral Analysis
Contents
2014
Volume: 34 Issue 12
55 Article(s)
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Research Article
Infrared Radiation Experimental Measurement and Analyse of Carbon Dioxide at High Temperature
ZHANG Jun, WANG Guo-lin, MA Hao-jun, and LIU Li-ping
This paper introduces the experiment technology for measuring the radiation of high temperature gas in the high frequency plasma wind tunnel. The infrared radiation of carbon dioxide at high temperature has been measured using this technology. We introduced the principium, flow field and the working gas of the high freThis paper introduces the experiment technology for measuring the radiation of high temperature gas in the high frequency plasma wind tunnel. The infrared radiation of carbon dioxide at high temperature has been measured using this technology. We introduced the principium, flow field and the working gas of the high frequency plasma wind tunnel. The experiment condition, equipment, method of data processing and the analyse of the experiment results were introduced. We had measured the infrared radiation of carbon dioxide at four different temperatures between 1 500 and 3 000 K using this technology for measuring the radiation of high temperature gas which had been developed by ourselves. Measuring the spatial distribution of the infrared radiation of carbon dioxide using Able-transform were also introduced. We have analyzed the emission spectrum at 4.3 μm of carbon dioxide at high temperature. The conclusion had been obtained that the center wavelength of the emission spectrum moved to the long wave when the temperature risen. The authors also had analyzed and contrasted the experiment results and the data obtained from literatures..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3169 (2014)
Study of High Temperature Water Vapor Concentration Measurement Method Based on Absorption Spectroscopy
CHEN Jiu-ying, LIU Jian-guo, HE Jun-feng, HE Ya-bai, ZHANG Guang-le, XU Zhen-yu, GANG Qiang, WANG Liao, YAO Lu, YUAN Song, RUAN Jun, DAI Yun-hai, and KAN Rui-feng
Tunable diode laser absorption spectroscopy (TDLAS) has been developed to realize the real-time and dynamic measurement of the combustion temperature, gas component concentration, velocity and other flow parameters, owing to its high sensitivity, fast time response, non-invasive character and robust nature. In order toTunable diode laser absorption spectroscopy (TDLAS) has been developed to realize the real-time and dynamic measurement of the combustion temperature, gas component concentration, velocity and other flow parameters, owing to its high sensitivity, fast time response, non-invasive character and robust nature. In order to obtain accurate water vapor concentration at high temperature, several absorption spectra of water vapor near 1.39 μm from 773 to 1 273 K under ordinary pressure were recorded in a high temperature experiment setup using a narrow band diode laser. The absorbance of high temperature absorption spectra was calculated by combined multi-line nonlinear least squares fitting method. Two water vapor absorption lines near 7 154.35 and 7 157.73 cm-1 were selected for measurement of water vapor at high temperature. A model method for high temperature water vapor concentration was first proposed. Water vapor concentration from the model method at high temperature is in accordance with theoretical reasoning, concentration measurement standard error is less than 0.2%, and the relative error is less than 6%. The feasibility of this measuring method is verified by experiment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3174 (2014)
Preparation and Luminescent Properties of Light Scattering Fluorescent Resin
XIAO Yao, FAN Guang-han, PI Hui, XU Yi-qin, CHEN Zhi-wu, HE Long-fei, YU Xiao-peng, ZHANG Li, ZHENG Shu-wen, and ZHANG Tao1*
With the methods of compound-melting and high-temperature molding, PC/YAG∶Ce fluorescent resin pieces were prepared. The transmittance of the prepared PC/YAG∶Ce fluorescent resin in 500～800 nm reaches approximately 65% (0.71 mm thick, double sides polished). The fluorescent resin was characterized by XRD, SEM and PL. TWith the methods of compound-melting and high-temperature molding, PC/YAG∶Ce fluorescent resin pieces were prepared. The transmittance of the prepared PC/YAG∶Ce fluorescent resin in 500～800 nm reaches approximately 65% (0.71 mm thick, double sides polished). The fluorescent resin was characterized by XRD, SEM and PL. The X-ray diffraction (XRD) patterns demonstrated that the fluorescent resin was pure Y3Al5O12 phase. The scanning electron microscopy (SEM) images showed that YAG phosphor was distributed evenly in the fluorescent resin. The excitation spectra had a weak peak at 342 nm and a strong band at 448 nm. The broad emission peaks at about 532 nm can be attributed to 5d→4f transition of Ce3+ ions. Decay curves for the fluorescence of PC/YAG∶Ce fluorescent resin show that the lifetime of the fluorescent resin was 61.5 ns. The luminous efficacy of the white LED packaged by the fluorescent resin and blue LED chip was 81.12 lm·W-1 at 100 mA. All results above of PC/YAG∶Ce fluorescent resin indicate a promising fluorescent material for white LEDs..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3178 (2014)
Research on the Identification Method of LTE Condition in the Laser-Induced Plasma
FAN Juan-juan, HUANG Dan, WANG Xin, ZHANG Lei*, MA Wei-guang, DONG Lei, YIN Wang-bao*, and JIA Suo-tang
Because of the poor accuracy of the commonly used Boltzmann plot method and double-line method, the Boltzmann-Maxwell distribution combined with the Saha-Eggert formula is proposed to improve the measurement accuracy of the plasma temperature;the simple algorithm for determining the linewidth of the emission line was eBecause of the poor accuracy of the commonly used Boltzmann plot method and double-line method, the Boltzmann-Maxwell distribution combined with the Saha-Eggert formula is proposed to improve the measurement accuracy of the plasma temperature;the simple algorithm for determining the linewidth of the emission line was established according to the relationship between the area and the peak value of the Gaussian formula, and the plasma electron density was calculated through the Stark broadening of the spectral lines;the method for identifying the plasma local thermal equilibrium (LTE) condition was established based on the McWhirter criterion. The experimental results show that with the increase in laser energy, the plasma temperature and electron density increase linearly;when the laser energy changes within 127～510 mJ, the plasma electron density changes in the range of 1.305 32×1017～1.873 22×1017 cm-3, the plasma temperature changes in the range of 12 586～12 957 K, and all the plasma generated in this experiment meets the LTE condition threshold according to the McWhirter criterion. For element Al, there exist relatively few observable lines at the same ionization state in the spectral region of the spectrometer, thus it is unable to use the Boltzmann plane method to calculate temperature. One hundred sets of Al plasma spectra were used for temperature measurement by employing the Saha-Boltzmann method and the relative standard deviation (RSD) value is 0.4%, and compared with 1.3% of the double line method, the accuracy has been substantially increased. The methods proposed can be used for rapid plasma temperature and electron density calculation, the LTE condition identification, and are valuable in studies such as free calibration, spectral effectiveness analysis, spectral temperature correction, the best collection location determination, LTE condition distribution in plasma, and so on..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3183 (2014)
The Principle of Temperature Measurement of a Non-Diffuse Emitter
XIN Cheng-yun, SONG Zheng-chang, DAI Jing-min, ZHANG Yu, LI Yi-min, and DU Xiang-han
In order to measure the temperature of the object in the case of non-diffuse emission within a finite solid angle, a new concept for radiation thermometry, the apparent emissivity, has been presented firstly after a proper mathematical transformation of the radiation measurement equation and its characteristics have alIn order to measure the temperature of the object in the case of non-diffuse emission within a finite solid angle, a new concept for radiation thermometry, the apparent emissivity, has been presented firstly after a proper mathematical transformation of the radiation measurement equation and its characteristics have also been investigated. The results indicated that although the apparent emissivity is complex in form, it is only the function of the wavelength for one measurement even if the object is non-diffuse. So the temperature of the object in the case of non-diffuse emission within a finite solid angle can be solved by modeling the apparent emissivity. Then the equations for monochromatic and wavelength radiation measurement were deduced. At the same time, the measurement of temperature for a finite area was investigated, and it can be found that if the temperatures of the finite area are the same, they can also be determined by modeling the apparent emissivity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3188 (2014)
Study on the Spectroscopic Data and Vibrational Levels of the Ground SiH+ Molecular Ion
ZHAO Jun, and ZENG Hui
The ground electronic state and the reasonable dissociation limit of SiH+ molecular ion have been correctly determined based on group theory and atomic and molecular reaction statics. The energy, equilibrium geometry and harmonic frequency of the ground electronic state of SiH+ molecular ion have been calculated using The ground electronic state and the reasonable dissociation limit of SiH+ molecular ion have been correctly determined based on group theory and atomic and molecular reaction statics. The energy, equilibrium geometry and harmonic frequency of the ground electronic state of SiH+ molecular ion have been calculated using the method QCISD(T)/cc-pVQZ. The whole potential curves for the ground electronic state is further scanned using the above method, the potential energy functions and relevant spectroscopic constants of this state are then first obtained by least square fitting to the Murrell-Sorbie function (n=9) and the modified Murrell-Sorbie+c6 function, respectively. The present results showed that the calculated results based on the Murrell-Sorbie function (n=9) are in better agreement with the experimental values, with the relative errors between spectroscopic constants and the experimental values being 0.13%, 3.07%, 0.38%, 5.25% and 0.52% respectively. With the potential obtained at the QCISD(T)/cc-pVQZ level of theory, the total of 27 vibrational states are predicted when J=0 by numerically solving the radial Schrodinger equation of nuclear motion. The complete vibrational levels, inertial rotation and six centrifugal distortion constants are obtained for the ground electronic state of SiH+ molecular ion for the first time. Calculation results in the present work may provide theoretical supports for the further study of SiH+ molecular ion..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3192 (2014)
Preparation of MgxZn1-xO Nanofibers Using PVP Nanofibers as Templates by Atom Layer Deposition and Their Optical Properties
JIA Hui-min, TANG Ji-long, FANG Xuan, WANG Shuang-peng, ZHAO Hai-feng, FANG Dan, WANG Xiao-hua, FANG Fang, LI Jin-hua, CHU Xue-ying, WEI Zhi-peng, MA Xiao-hui, and XU Li
In the present paper, MgxZn1-xO nanofibers with different doping concentration were prepared by atom layer deposition (ALD) using polyvinyl pyrrolidone (PVP) nanofibers as template, which were synthesized by electrospinning. The influence of different Mg doping concentration on the structure and optical properties of cIn the present paper, MgxZn1-xO nanofibers with different doping concentration were prepared by atom layer deposition (ALD) using polyvinyl pyrrolidone (PVP) nanofibers as template, which were synthesized by electrospinning. The influence of different Mg doping concentration on the structure and optical properties of composite nanofibers was investigated. The samples were characterized by field emission scanning electron microscopy (FESEM), ultraviolet visible (UV-Vis)absorption spectroscopy and photoluminescence (PL) spectra. The doping of Mg did not change the morphologies of ZnO nanofibers, the morphologies of all the samples were very similar while the diameter of MgxZn1-xO-PVP composite nanofibers became larger after doping. With the increase in the Mg doping concentration, the absorption edge shifted to larger energy side, revealing the band gap tenability of MgxZn1-xO nanofibers. Meanwhile, a significant blue shift of the UV emission peak from 377 to 362 nm was observed in PL spectra. Compared with ZnO-PVP composite nanofibers, the UV emission intensity of MgxZn1-xO-PVP composite nanofibers was much stronger. Component control MgxZn1-xO nanofibers can be synthesized by this method. The doping of Mg elements in ZnO can effectively improve the band gap of ZnO-PVP nanofibers and the intensity of UV emission..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3197 (2014)
Experimental Study of Ultralow Frequency Modulation Photoassociation Spectrum
WANG Li-rong, MA Jie, ZHAO Yan-ting, XIAO Lian-tuan, and JIA Suo-tang
In the present paper, ultracold cesium atoms were obtained in magnetic optical trap using the laser cooling technology. The number of ultracold atoms is 107. The temperature of ultracold atoms is about 200 μK and the diameter of the ultracold atoms cloud is about 400 μm. The ultracold cesium molecules of excited statesIn the present paper, ultracold cesium atoms were obtained in magnetic optical trap using the laser cooling technology. The number of ultracold atoms is 107. The temperature of ultracold atoms is about 200 μK and the diameter of the ultracold atoms cloud is about 400 μm. The ultracold cesium molecules of excited states were formed using the photoassociation of ultracold atoms. The resolution of vib-rotational spectrum was studied under different scan rates of photossociation laser in the experiment. The resolution of vib-rotational spectrum becomes high when the scan rate of photossociation laser becomes slow. The cold atoms fluorescence was obtained using the high sensitive avalanche photo detector and the high resolution vib-rotational spectrum of ultracold cesium molecule in its first excited state of with dissociation limit long range state was obtained. The ultracold ground molecule was formed by controlled Raman photoassociation and the photoassociation laser must be locked to atom-molecular hyperfine transitions. The ultracold atoms photoassociation spectrum was modulated using ultra-low frequency. The first-order differential signal was optimized by changing modulation amplitude and modulation frequency. It provides a feedback signal to correct error of the laser. The laser frequency satisfies experimental requirement to form ultracold ground molecules using the controlled Raman photoassociation. This work is important for studies of ultracold atoms and molecules in confined space..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3201 (2014)
Research on the Progress in the Light-Emitting Mechanism of ZnO in the Visible Region
WANG Ji-hong, XU Chang-shan, XUE Xiang-xin, and ZHAO Bing
In the past few years we have witnessed a revival of, and subsequent rapid expansion in, the research on zinc oxide (ZnO). We present a review of current research on the optical properties of ZnO. The wide range of useful properties displayed by ZnO has been recognized for a long time. The high electron mobility, high In the past few years we have witnessed a revival of, and subsequent rapid expansion in, the research on zinc oxide (ZnO). We present a review of current research on the optical properties of ZnO. The wide range of useful properties displayed by ZnO has been recognized for a long time. The high electron mobility, high thermal conductivity, wide and direct band gap and large exciton binding energy make ZnO suitable for a wide range of devices, including two light-emitting tubes, transparent thin-film transistors, laser diodes that operate in the blue and ultraviolet region of the spectrum, and ultraviolet detector. Optically pumped lasing has been reported in ZnO platelets, ZnO thin films, and clusters consisting of ZnO nanocrystals and ZnO nanowires. Up to now, a number of synthetic methods including electrospinning, hydrothermal, sol-hydrothermal, chemical vapor deposition, spin coating and electrochemical deposition have been used to prepare ZnO nanomaterials such as nanofibers, nanowires, nanorods and so on. The growth and properties of ZnO nanostructures have been extensively studied, but the photoluminescence mechanism in the visible range has seldom been summarized. The photoluminescence spectra can reflect some important information such as surface defects and oxygen vacancies, surface states, photo-induced charge carrier separation and recombination processes in nano-sized semiconductor materials. The optical emission of ZnO is equally complex, with a variety of defect emission states whose structural origins remain controversial. A detailed discussion of photoluminescence, in the visible spectral range, is provided. In this review, we provided a detailed overview on the luminescence mechanism of ZnO nanostructures in the visible range. The review detail exhibits the following four mechanisms of the optical properties of ZnO in the visible range: the influence of the quantum confinement effect, the band edge modulation that has effect of photoluminescence, the influence of surface modification, and the control of defects’ concentration..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3205 (2014)
Syntheses and Luminescence Investigation of CaAl12O19: xMn4+ Red Phosphors
TONG Yi-ping, and YAN Jia-yan
CaAl12O19: xMn4+(x=0.0～0.001 84 mol) red phosphors were prepared by high-temperature solid state method. Different influencing factors, i.e. the doping amount of Mn4+, and sintering temperature, were investigated by the orthogonal experiment design. The optimum conditions for preparing CaAl12O19∶xMn4+ phosphors are: siCaAl12O19: xMn4+(x=0.0～0.001 84 mol) red phosphors were prepared by high-temperature solid state method. Different influencing factors, i.e. the doping amount of Mn4+, and sintering temperature, were investigated by the orthogonal experiment design. The optimum conditions for preparing CaAl12O19∶xMn4+ phosphors are: sintering temperature 1 500 ℃, and x=0.014 7 mol. It emits strong deep red light with emission maximal peak at 656 nm, and two shoulder peaks (643 and 666 nm), the corresponding excitation peak is located at 470 nm. The 656 nm emission peak is ascribed to the 2E→4A2 transition, and the shoulder peaks (643 and 666 nm) are attributed to phonon sideband transitions. The 470 nm excitation peak is ascribed to the ligand-field 4A2→4T2 transition (d→d band). Owing to the fact that the excitation peak (470 nm) is near the emission (460 nm) of commercial LED chips, it is quite suitable for red light candidate for LED light resources..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3210 (2014)
Upconversion Luminescence of Er3+-Doped Yttrium-Stabilized Zirconia Powders
XU Bin, ZHOU Yong-qiang, WANG He, and CAO Li-li
Er3+-doped yttrium-stabilized zirconia upconversion powders Zr0.92-xY0.08O1.96-0.5x:xEr3+(x=0.001~0.11)were synthesized via chemical coprecipitation method at 1 200 ℃ for 3 hours. Phase structure and upconversion luminescence spectra of the samples were characterized by X-ray diffractometer and fluorescence spectrometeEr3+-doped yttrium-stabilized zirconia upconversion powders Zr0.92-xY0.08O1.96-0.5x:xEr3+(x=0.001~0.11)were synthesized via chemical coprecipitation method at 1 200 ℃ for 3 hours. Phase structure and upconversion luminescence spectra of the samples were characterized by X-ray diffractometer and fluorescence spectrometer, respectively. The proposed upconversion mechanism of the samples was discussed. The results indicate that good crystallinity cubic ZrO2 solid solution can be stabilized by introducing 8 mol% yttrium ions. Size and valent differences between trivalent Y3+ and quadrivalent Zr4+ ions generate asymmetry and oxygen vacancies, which contribute to the stability of upconversion luminescence properties and luminescence intensity increase of the samples, and expand its practical application fields. Under 980nm excitation, the samples emit green light centered at 539 nm(2H11/2→4I15/2), 552 nm(4S3/2→4I15/2) and red light at 656 and 680 nm (4F9/2→4I15/2). When Er3+ doping concentration (0.1 mol%) is low, the main green emission of samples is ascribed to the excited state absorption (ESA) processes;With the Er3+concentration increases from 0.1% to 11 mol%, there exist three cross relaxation (CR) processes: 2H11/2+4I15/2→4I9/2+4I13/2, 4F7/2+4I11/2→2 4F9/2 and 4I15/2+4I9/2→2 4I13/2, causing that the red emissions increase markedly whereas the green emissions decrease. When Er3+ doping concentration(9 mol%) is high, the sample mainly presents red luminescence due to the dominated CR processes in upconversion process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3214 (2014)
Scattering Properties of Core-Shell Structure of Mist Wrapped Dust Particles
FENG Shi-qi, SONG Wei, WANG Yan, MIAO Xin-hui, XU Li-jun, LIU Yu, LI Cheng, LI Wen-long, WANG Yi-ran, and CAI Hong-xing
The authors have investigated the optical properties of core-shell structure of mist wrapped dust particles based on the method of discrete dipole approximation (DDA). The influence on the thickness of the elliptical core-shell structure were calculated which the ratio of long axis and short axis is 2∶1, and the changeThe authors have investigated the optical properties of core-shell structure of mist wrapped dust particles based on the method of discrete dipole approximation (DDA). The influence on the thickness of the elliptical core-shell structure were calculated which the ratio of long axis and short axis is 2∶1, and the change of scattering angle for scattering characteristics. The results shows that the thickness of outer layer increase from 1.2 to 4.8 μm with the scattering and extinction coefficient of double core-shell layers particles decrease from 3.4 and 3.43 to 2.543 and 2.545, when the size of inner core isn’t change. And scattering relative strength also increased obviously. The thickness of inner core increase from 0.6 to 2.4 μm with the of scattering and extinction coefficient change from 2.59 and 2.88 to 2.6 and 2.76 when thickness of outer remain constant. Effect of the thickness of visible outer layer on the scattering characteristics of double core-shell layers particles is greater, because of the interaction between scattering light and outer materials. The scattering relative intensity decrease with wavelength increased, while increased with the scale of core-shell structure increase. The results make a promotion on the study of the transportation characteristics of laser and scattering characteristics when the atmospheric aerosol and water mist interact together..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3218 (2014)
Photoinduced Intra-Molecular Energy Transfer of a Novel Phthalocyanine Zinc(Ⅱ) Bearing Poly (Aryl Benzyl Ether) Dendritic Substitutents with Carboxylic Terminal
ZHENG Si-ning, CHEN Wan-ling, and PENG Yi-ru
The photoinduced intra-molecular energy transfer in phthalocyanine zinc(Ⅱ) bearing poly (aryl benzyl ether) dendritic substituents with carboxylic terminal was studied by steady-state, time-resolved fluorescence and UV/Vis spectroscopic methods. The result shows that the complexes mainly existed as monomers in dimethylThe photoinduced intra-molecular energy transfer in phthalocyanine zinc(Ⅱ) bearing poly (aryl benzyl ether) dendritic substituents with carboxylic terminal was studied by steady-state, time-resolved fluorescence and UV/Vis spectroscopic methods. The result shows that the complexes mainly existed as monomers in dimethyl sulfoxide. The light-harvesting ability of this series of dendritic phthalocyanines increased with the dendron generation under 270 nm. The effects of the dendron generation on the fluorescence characteristics of phthalocyanine cores was significantly, and the fluorescence lifetime and fluorescent quantum yield decreased with the increase of the dendron generation. Intra-molecular energy could be transferred from peripheral dendron acting as an energy hydrazine to the phthalocyanine core during a photo-induced process. With the dendrimer increasing, the intra-molecular energy transfer quantum yield increased. These results obviously indicated that this series of dendritic phthalocyanines is a king of novel compound with light-harvesting structure..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3224 (2014)
Spectroscopic Study of Laser Induced Breakdown Plasma Spectroscopy in Air and Semi-Empirical Simulation
SUN Dui-xiong, SU Mao-gen, DONG Chen-zhong, MA Yun-yun, YANG Feng, and CAO Shi-quan
A laser induced breakdown spectroscopy experiment was carried out using Nd∶YAG laser in air, and time-resolved spectra were measured. Based on local thermodynamic equilibrium assumption, a method used to simulate LIBS spectra is proposed. A LIBS spectrum of air in the wavelength range of 700~900 nm was simulated using A laser induced breakdown spectroscopy experiment was carried out using Nd∶YAG laser in air, and time-resolved spectra were measured. Based on local thermodynamic equilibrium assumption, a method used to simulate LIBS spectra is proposed. A LIBS spectrum of air in the wavelength range of 700~900 nm was simulated using this method. A good agreement between experiment and simulation was obtained, and moreover, the relative concentrations of the N, O and Ar in air were obtained..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3230 (2014)
Discrimination of Varieties of Borneol Using Terahertz Spectra Based on Principal Component Analysis and Support Vector Machine
LI Wu, HU Bing, and WANG Ming-wei
In the present paper, the terahertz time-domain spectroscopy (THz-TDS) identification model of borneol based on principal component analysis (PCA) and support vector machine (SVM) was established. As one Chinese common agent, borneol needs a rapid, simple and accurate detection and identification method for its differeIn the present paper, the terahertz time-domain spectroscopy (THz-TDS) identification model of borneol based on principal component analysis (PCA) and support vector machine (SVM) was established. As one Chinese common agent, borneol needs a rapid, simple and accurate detection and identification method for its different source and being easily confused in the pharmaceutical and trade links. In order to assure the quality of borneol product and guard the consumer’s right, quickly, efficiently and correctly identifying borneol has significant meaning to the production and transaction of borneol. Terahertz time-domain spectroscopy is a new spectroscopy approach to characterize material using terahertz pulse. The absorption terahertz spectra of blumea camphor, borneol camphor and synthetic borneol were measured in the range of 0.2 to 2 THz with the transmission THz-TDS. The PCA scores of 2D plots (PC1×PC2) and 3D plots (PC1×PC2×PC3) of three kinds of borneol samples were obtained through PCA analysis, and both of them have good clustering effect on the 3 different kinds of borneol. The value matrix of the first 10 principal components (PCs) was used to replace the original spectrum data, and the 60 samples of the three kinds of borneol were trained and then the unknown 60 samples were identified. Four kinds of support vector machine model of different kernel functions were set up in this way. Results show that the accuracy of identification and classification of SVM RBF kernel function for three kinds of borneol is 100%, and we selected the SVM with the radial basis kernel function to establish the borneol identification model. In addition, in the noisy case, the classification accuracy rates of four SVM kernel function are above 85%, and this indicates that SVM has strong generalization ability. This study shows that PCA with SVM method of borneol terahertz spectroscopy has good classification and identification effects, and provides a new method for species identification of borneol in Chinese medicine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3235 (2014)
Application of Interval Selection Methods in Quantitative Analysis of Multicomponent Mixtures by Terahertz Time-Domain Spectroscopy
CHEN Tao, LI Zhi, MO Wei, and HU Fang-rong
Interval selection methods combined with terahertz time-domain spectroscopy (THz-TDS) technique were used to perform quantitative analysis of component concentrations in multicomponent mixtures. The THz spectra of 100 quaternary pharmaceutical mixtures composed of lactose monohydrate, acetaminophen, microcrystalline ceInterval selection methods combined with terahertz time-domain spectroscopy (THz-TDS) technique were used to perform quantitative analysis of component concentrations in multicomponent mixtures. The THz spectra of 100 quaternary pharmaceutical mixtures composed of lactose monohydrate, acetaminophen, microcrystalline cellulose and soluble starch were measured using THz-TDS system. Four spectral interval selection methods, including iPLS, mwPLS, siPLS and biPLS, were employed to select spectral intervals of THz absorbance spectra of multicomponent mixtures and correlate THz absorbance spectra with the concentrations of lactose monohydrate. The mwPLS method yielded the most accurate result as compared with the other three interval selection methods and full-spectrum PLS. The optimal mwPLS model was obtained with lower root mean square error of cross-validation (RMSECV) of 0.980 3, lower root mean square error of prediction (RMSEP) of 1.114 1, higher correlation coefficient for calibration (RC) of 0.996 0, and higher correlation coefficient for prediction (RP) of 0.995 1. Experimental results demonstrate that spectral interval selection combined with THz-TDS could be successfully applied as an accurate and rapid method to determine component concentrations in multicomponent mixtures..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3241 (2014)
Non-Destructive and Fast Identification of Cotton-Polyester Blend Fabrics by the Portable Near-Infrared Spectrometer
LI Wen-xia, LI Feng, ZHAO Guo-liang, TANG Shi-jun, and LIU Xiao-ying
A series of 376 cotton-polyester (PET) blend fabrics were studied by a portable near-infrared (NIR) spectrometer. A NIR semi-quantitative-qualitative calibration model was established by Partial Least Squares (PLS) method combined with qualitative identification coefficient. In this process, PLS method in a quantitativA series of 376 cotton-polyester (PET) blend fabrics were studied by a portable near-infrared (NIR) spectrometer. A NIR semi-quantitative-qualitative calibration model was established by Partial Least Squares (PLS) method combined with qualitative identification coefficient. In this process, PLS method in a quantitative analysis was used as a correction method, and the qualitative identification coefficient was set by the content of cotton and polyester in blend fabrics. Cotton-polyester blend fabrics were identified qualitatively by the model and their relative contents were obtained quantitatively, the model can be used for semi-quantitative identification analysis. In the course of establishing the model, the noise and baseline drift of the spectra were eliminated by Savitzky-Golay(S-G) derivative. The influence of waveband selection and different pre-processing method was also studied in the qualitative calibration model. The major absorption bands of 100% cotton samples were in the 1 400～1 600 nm region, and the one for 100% polyester were around 1 600～1 800 nm, the absorption intensity was enhancing with the content increasing of cotton or polyester. Therefore, the cotton-polyesters major absorption region was selected as the base waveband, the optimal waveband (1 100～2 500 nm) was found by expanding the waveband in two directions (the correlation coefficient was 0.6, and wave-point number was 934). The validation samples were predicted by the calibration model, the results showed that the model evaluation parameters was optimum in the 1 100～2 500 nm region, and the combination of S-G derivative, multiplicative scatter correction (MSC) and mean centering was used as the pre-processing method. RC (relational coefficient of calibration) value was 0.978, RP (relational coefficient of prediction) value was 0.940, SEC (standard error of calibration) value was 1.264, SEP (standard error of prediction) value was 1.590, and the samples recognition accuracy was up to 93.4%. It showed that the cotton-polyester blend fabrics could be predicted by the semi-quantitative-qualitative calibration model..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3246 (2014)
Huanghua Pear Soluble Solids Contents Vis/NIR Spectroscopy by Analysis of Variables Optimization and FICA
XU Wen-li, SUN Tong, HU Tian, HU Tao, and LIU Mu-hua
The purpose of this study was to establish a mathematical model of the visible/near-infrared (Vis/NIR) diffuse transmission spectroscopy with fine stability and precise predictability for the non destructive testing of the soluble solids content of huanghua pear, through comparing the effects of various pretreatment meThe purpose of this study was to establish a mathematical model of the visible/near-infrared (Vis/NIR) diffuse transmission spectroscopy with fine stability and precise predictability for the non destructive testing of the soluble solids content of huanghua pear, through comparing the effects of various pretreatment methods, variable optimization method, fast independent principal component analysis (FICA) and least squares support vector machines (LS-SVM) on mathematica model for SSC of huanghua pear, and the best combination of methods to establish model for SSC of huanghua pear was got. Vis/NIR diffuse transmission spectra of huanghua pear were acquired by a Quality Spec spectrometer, three methods including genetic algorithm, successive projections algorithm and competitive adaptive reweighted sampling (CARS) were used firstly to select characteristic variables from spectral data of huanghua pears in the wavelength range of 550~950 nm, and then FICA was used to extract factors from the characteristic variables, finally, validation model for SSC in huanghua pears was built by LS-SVM on the basic of those parameters got above. The results showed that using LS-SVM on the foundation of the 21 variables screened by CARS and the 12 factors selected by FICA, the CARS-FICA-LS-SVM regression model for SSC in huanghua pears was built and performed best, the coefficient of determination and root mean square error of calibration and prediction sets were R2C=0.974, RMSEC=0.116%, R2P=0.918, and RMSEP=0.158% respectively, and compared with the mathematical model which uses PLS as modeling method, the number of variables was down from 401 to 21, the factors were also down from 14 to 12, the coefficient of determination of modeling and prediction sets were up to 0.023 and 0.019 respectively, while the root mean square errors of calibration and prediction sets were reduced by 0.042% and 0.010% respectively. These experimental results showed that using CARS-FICA-LS-SVM to build regression model for the forecast of SSC in huanghua pears can simplify the prediction model and improve the detection precision..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3253 (2014)
Determination of Cotton Content in Cotton/Ramie Blended Fabric by NIR Spectra and Variable Selection Methods
SUN Tong, GENG Xiang, and LIU Mu-hua
Rapid detection of textile fiber components is very important for production process of quality control, trading and market surveillance. The objective of this research was to assess cotton content in cotton/ramie blended fabric quickly by near infrared (NIR) spectrum technology and variable selection methods. ReflectaRapid detection of textile fiber components is very important for production process of quality control, trading and market surveillance. The objective of this research was to assess cotton content in cotton/ramie blended fabric quickly by near infrared (NIR) spectrum technology and variable selection methods. Reflectance spectra of samples were acquired by a NIRFlex N-500 Fourier spectroscopy in the range of 4 000～10 000 cm-1, primary election of spectral range and pretreatment analysis were conducted first. Then, three variable selection methods such as UVE (uninformative variables elimination), SPA (successive projections algorithm) and CARS (competitive adaptive reweighted sampling) were used to select sensitive variables. After that, PLS (partial least squares) was used to develop calibration model for cotton content of cotton/ramie blended fabric, and the best calibration model was used to predict cotton content of samples in prediction set. The result indicates that range of 4 052～8 000 cm-1 is optimal spectral range for cotton content modeling. CARS method is an efficient method to improve model performance, the correlation coefficient and root mean square error of CARS-PLS for calibration and prediction sets are 0.903, 0.749 and 8.01%, 12.93%, respectively. So NIR spectra combined with CARS method is feasible for assessing cotton content in cotton/ramie blended fabric, and CARS method can simplify model, improve model performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3257 (2014)
Determination of Calcium and Magnesium in Tobacco by Near-Infrared Spectroscopy and Least Squares-Support Vector Machine
TIAN Kuang-da, QIU Kai-xian, LI Zu-hong, Lv Ya-qiong, ZHANG Qiu-ju, XIONG Yan-mei, and MIN Shun-geng
The purpose of the present paper is to determine calcium and magnesium in tobacco using NIR combined with least squares-support vector machine (LS-SVM). Five hundred ground and dried tobacco samples from Qujing city, Yunnan province, China, were surveyed by a MATRIX-I spectrometer (Bruker Optics, Bremen, Germany). At tThe purpose of the present paper is to determine calcium and magnesium in tobacco using NIR combined with least squares-support vector machine (LS-SVM). Five hundred ground and dried tobacco samples from Qujing city, Yunnan province, China, were surveyed by a MATRIX-I spectrometer (Bruker Optics, Bremen, Germany). At the beginning of data processing, outliers of samples were eliminated for stability of the model. The rest 487 samples were divided into several calibration sets and validation sets according to a hybrid modeling strategy. Monte-Carlo cross validation was used to choose the best spectral preprocess method from multiplicative scatter correction (MSC), standard normal variate transformation (SNV), S-G smoothing, 1st derivative, etc., and their combinations. To optimize parameters of LS-SVM model, the multilayer grid search and 10-fold cross validation were applied. The final LS-SVM models with the optimizing parameters were trained by the calibration set and accessed by 287 validation samples picked by Kennard-Stone method. For the quantitative model of calcium in tobacco, Savitzky-Golay FIR smoothing with frame size 21 showed the best performance. The regularization parameter λ of LS-SVM was e16.11, while the bandwidth of the RBF kernel σ2 was e8.42. The determination coefficient for prediction (R2c) was 0.975 5 and the determination coefficient for prediction (R2p) was 0.942 2, better than the performance of PLS model (R2c=0.959 3, R2p=0.934 4). For the quantitative analysis of magnesium, SNV made the regression model more precise than other preprocess. The optimized λ was e15.25 and σ2 was e6.32. R2c and R2p were 0.996 1 and 0.930 1, respectively, better than PLS model (R2c=0.971 6, R2p=0.892 4). After modeling, the whole progress of NIR scan and data analysis for one sample was within tens of seconds. The overall results show that NIR spectroscopy combined with LS-SVM can be efficiently utilized for rapid and accurate analysis of calcium and magnesium in tobacco..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3262 (2014)
Effect of Algorithms for Calibration Set Selection on Quantitatively Determining Asiaticoside Content in Centella Total Glucosides by Near Infrared Spectroscopy
ZHAN Xue-yan, ZHAO Na, LIN Zhao-zhou, WU Zhi-sheng, YUAN Rui-juan, and QIAO Yan-jiang
The appropriate algorithm for calibration set selection was one of the key technologies for a good NIR quantitative model. There are different algorithms for calibration set selection, such as Random Sampling (RS) algorithm, Conventional Selection (CS) algorithm, Kennard-Stone(KS) algorithm and Sample set Portioning baThe appropriate algorithm for calibration set selection was one of the key technologies for a good NIR quantitative model. There are different algorithms for calibration set selection, such as Random Sampling (RS) algorithm, Conventional Selection (CS) algorithm, Kennard-Stone(KS) algorithm and Sample set Portioning based on joint x-y distance (SPXY) algorithm, et al. However, there lack systematic comparisons between two algorithms of the above algorithms. The NIR quantitative models to determine the asiaticoside content in centella total glucosides were established in the present paper, of which 7 indexes were classified and selected, and the effects of CS algorithm, KS algorithm and SPXY algorithm for calibration set selection on the accuracy and robustness of NIR quantitative models were investigated. The accuracy indexes of NIR quantitative models with calibration set selected by SPXY algorithm were significantly different from that with calibration set selected by CS algorithm or KS algorithm, while the robustness indexes, such as RMSECV and |RMSEP-RMSEC|, were not significantly different. Therefore, SPXY algorithm for calibration set selection could improve the predicative accuracy of NIR quantitative models to determine asiaticoside content in centella total glucosides, and have no significant effect on the robustness of the models, which provides a reference to determine the appropriate algorithm for calibration set selection when NIR quantitative models are established for the solid system of traditional Chinese medcine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3267 (2014)
Quality Anlysis of the before Redrying Raw Tobacco & after Redrying Sheet Tobacco by Using Online Near Infrared Spectroscopy
TANG Zhao-qi, LIU Ying, SHU Ru-xin, YANG Kai, ZHAO Long-lian, ZHANG Lu-da, ZHANG Ye-hui, and LI Jun-hui
In this paper, the 7 different origin before redrying raw tobacco & after redrying sheet tobacco’s online near infrared spectroscopy were collected from sorting & redrying production line specifically for “ZHONGHUA” brand. By using the projection model bulit by different origin tobacco’s online spectroscopy andIn this paper, the 7 different origin before redrying raw tobacco & after redrying sheet tobacco’s online near infrared spectroscopy were collected from sorting & redrying production line specifically for “ZHONGHUA” brand. By using the projection model bulit by different origin tobacco’s online spectroscopy and the method of variance and correlation analysis, we studied the uniformity and similarity quality characteristics change before and after the redrying of tobacco, which can provide support for understanding the quality of the tobacco material and cigarette product formulations. This study show that selecting about 10 000 by equally spaced sampling time from a huge number of online near infrared spectroscopy, for modeling are feasible, and representative. After manual sorting, threshing, and redrying, the uiformity of each origin tobacco near-infrared spectroscopy can be increased by 10%～35%, homogeneity of the tobacco leaf has been significantly improved. After redrying, the similar relationship embodied in the origin also have significant changes, overall it reduce significantly, that shows the quality differences embodied by origin significantly improve, which can provide greater space for formulations, it shows the need for high-quality Chinese cigarette production requires large amounts of financial and human resources to implement cured tobacco processing. The traditional means of chemical analysis, it takes a lot of time and effort, it is difficult to control the entire processing chain, Near Infrared Spectroscopy with its rapid, non-destructive advantage, not only can achieve real-time detection and quality control, but also can take full advantage of near-infrared spectroscopy information created in the production process, which is a very promising online analytical detection technology in many industries especially in the agricultural and food processing industries..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3273 (2014)
Analysis of Tobacco Site Features Using Near-Infrared Spectroscopy and Projection Model
YANG Kai, CAI Jia-yue, ZHANG Chao-ping, SHU Ru-xin, LIANG Miao, ZHAO Long-lian, ZHANG Lu-da, ZHANG Ye-hui, and LI Jun-hui
In this paper, total of 5 170 flue-cured tobacco samples collected from 2003 to 2012 in the domestic and foreign origin by Shanghai Tobacco Group Technical Center were tested by near infrared spectroscopy, including the typical upper leaves 1 394, central 2 550, the lower part of 1 226. Using projection model of based In this paper, total of 5 170 flue-cured tobacco samples collected from 2003 to 2012 in the domestic and foreign origin by Shanghai Tobacco Group Technical Center were tested by near infrared spectroscopy, including the typical upper leaves 1 394, central 2 550, the lower part of 1 226. Using projection model of based on principal component and Fisher criterion (PPF), follow the projected results to get no statistically significant differences at adjacent principal components, and the number of principal components as little as possible, in this paper, four main components to build projection analysis model, the model results show that: the near-infrared spectral characteristics of the upper and lower leaves have a significant difference that can be achieved almost entirely distinguished;while the middle leaves with upper and lower have a certain degree of overlap, which is consistent to the actual situation of the continuity of tobacco leaf. At the same time, Euclidean distance between the predicted sample projection values and the mean projection values of each class in the model, a description is given for the prediction samples to quantify the extent of the site features, and its first and second close categories. Using the dispersion of projected values in model and the given threshold value, prediction results can be refined into typically upper, upper to central , central to upper, typical central, central to the lower, the lower to central, typically the lower, or super-model range. The model was validated by 34 tobacco samples obtained from the re-drying process in 2012 with different origins and parts. This kind of analysis methods, not only can achieve discriminant analysis, and get richer feature attribute information, can provide guidance on the raw tobacco processing and formulations..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3277 (2014)
Comparison of the Function and Conformation of Human β-Casein and Bovine β-Casein by Spectroscopic Study
LIU Wei, LI Meng, REN Hao-wei, and LIU Ning
β-casein was the main component of human milk casein, but the content of β-casein in the bovine milk was less. The difference in β-casein content of the two samples was one of the reasons why human milk is more digestible than bovine milk. Studying the differences of structure and function in human and bovine milk β-caβ-casein was the main component of human milk casein, but the content of β-casein in the bovine milk was less. The difference in β-casein content of the two samples was one of the reasons why human milk is more digestible than bovine milk. Studying the differences of structure and function in human and bovine milk β-casein can help us develop a new human milk simulated infant formula which will be more suitable for the infant gut. The UV spectrophotometer was used to study the solubility, sulfhydryl and emulsification of human milk β-casein and bovine milk β-casein, Fluorescence spectroscopy and the infrared spectroscopy were used to study the structural characteristics of human milk β-casein and bovine milk β-casein. The two samples shared a similar isoelectric point (pH 4.0~5.0), the solubility of human milk β-casein (10.83%) was lower than which in bovine milk β-casein (11.83%) near the pI, while it was higher when it deviated the pI. The emulsion ability (110~140 m2·g-1) of human milk β-casein was higher than that in bovine milk β-casein (70~130 m2·g-1) and surface sulfhydryl group (SH) of two kinds of milk protein were similar ［(18.47±0.08) μmol·g-1 and (18.67±0.17) μmol·g-1］. The total sulfhydryl group ［(47.46±0.23) μmol·g-1］ in bovine milk β-casein was more than that in human milk β-casein ［(26.17±0.12) μmol·g-1］. Functional groups in two samples were similar and they both contained beta sheet, human milk β-casein had less H-bond and internal hydrophobic than bovine milk β-casein. The results showed that the two samples had similar functional groups, while human milk β-casein had much less secondary structure such as α-helix and β-sheet, a looser tertiary structure and a better interfacial activity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3281 (2014)
Acidity and Temperature Effect on the Fluorescence Characteristics of Hydraulic Oils and Lubricants
DENG Hu, ZHOU Xun, SHANG Li-ping, ZHANG Ze-lin, and WANG Shun-li
By analyzing HyJet V phosphate ester hydraulic oil environmental impacts (oil, etc.) and confounding factors (pH, temperature, etc.), the feasibility was studied for the fluorescence detection of aircraft hydraulic oil leaks. By using the fluorescence spectrophotometer at various acidities and temperatures, the fluoresBy analyzing HyJet V phosphate ester hydraulic oil environmental impacts (oil, etc.) and confounding factors (pH, temperature, etc.), the feasibility was studied for the fluorescence detection of aircraft hydraulic oil leaks. By using the fluorescence spectrophotometer at various acidities and temperatures, the fluorescence properties of HyJet V phosphate ester hydraulic oil, Jet Oil II lubricant and 2197 lubricant were gained. The experimental results are shown as following: The fluorescence peaks of HyJet V phosphate ester hydraulic oil, Jet Oil II lubricant and 2197 lubricant are at 362, 405 and 456 nm, respectively. The impact of temperature on HyJet V phosphate ester hydraulic oil is less effective;Jet Oil II lubricant and 2197 lubricant fluorescence intensity decreases with increasing temperature. When acidity increases, the fluorescence peak of HyJet V phosphate ester hydraulic oil gradient shifts from 370 to 362 nm, and the fluorescence intensity decreases;the fluorescence peak of Jet Oil II lubricant is always 405 nm, while the fluorescence intensity decreases;the fluorescence peak of 2197 lubricant at 456 nm red shifts to 523 nm, and double fluorescence peaks appeare. The results are shown as following: under the influence of the environment and interference factors, the fluorescence characteristics of HyJet V phosphate ester hydraulic oil remain unchanged, and distinguish from Jet Oil II lubricant and 2197 lubricant. Therefore, the experiments indicate that the detection of HyJet V phosphate ester hydraulic oil leak is feasible by using fluorescence method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3288 (2014)
Fluorescence Enhancement Effect of Silver Nanoparticles with Different Surface Modifiers and Sizes
WANG Yue-hui, XIONG Na-na, and ZHOU Ji
Silver nanoparticles were prepared by chemical method using citricacid trisodiumsalt (Ag-CTS) and polyvinylpyrrolidone (Ag-PVP) as surface modifiers, respectively. When Ag-CTS or Ag-PVP nanoparticles were added into methyl orange (MO) solution, the enhanced-fluorescence of S1→S0 and quenched-fluorescence of S2→S0 were Silver nanoparticles were prepared by chemical method using citricacid trisodiumsalt (Ag-CTS) and polyvinylpyrrolidone (Ag-PVP) as surface modifiers, respectively. When Ag-CTS or Ag-PVP nanoparticles were added into methyl orange (MO) solution, the enhanced-fluorescence of S1→S0 and quenched-fluorescence of S2→S0 were simultaneously observed. However, for the solution containing Ag-PVP, the red-shift of fluorescence peak of S1→S0 was observed and the extents of the enhanced-fluorescence of S1→S0 and quenched-fluorescence of S2→S0 are higher than those of the solution containing Ag-CTS. With the increase in reaction time the fluorescence intensity of S1→S0 increased gradually in the solution containing Ag-CTS nanoparticles and no change was observed in the solution containing Ag-PVP nanoparticles. The lower the MO concentration, the higher the fluorescence intensity ratio of S1→S0. The results indicated that the silver nanoparticles with different surface modifiers affect the metal-enhanced fluorescence by impacting the distance between the methyl orange and silver nanoparticles. The size of silver nanoparticles affects the metal-enhanced fluorescence due to the difference in the surface plasma resonance properties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3292 (2014)
Studies on the Interaction between Malanin and Metal Ions by Fluorescence Spectra Methods
YUAN Yan, ZHANG Wei, DAI Jian-hui, LIU Xiao-fang, WANG Hong-bin, Colin J Barrow, and YANG Wen-rong
A novel protein with anti-tumor activities named malanin was isolated and purified from an endemic plant in Yunnan and Guangxi provinces. Effects of copper ion, silver ion and calcium ion on malanin and apo-malanin fluorescence spectra were studied. The results showed that copper ion leads to obvious statistic quenchinA novel protein with anti-tumor activities named malanin was isolated and purified from an endemic plant in Yunnan and Guangxi provinces. Effects of copper ion, silver ion and calcium ion on malanin and apo-malanin fluorescence spectra were studied. The results showed that copper ion leads to obvious statistic quenching of malanin and apo-malanin fluorescence. The dissociation constant of them from malanin and apo-malanin were about 2.37×10-4 and 2.66×10-4 mol·L-1, respectively. The silver ion did not have quenching action on malanin fluorescence, but it had statistic quenching effect on apo-malanin fluorescence, and its dissociation constant was 2.37×10-4 mol·L-1. Calcium ion did not have quenching action on malanin and apo-malanin fluorescence. It plays an important role in keeping malanin natural conformation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3297 (2014)
Study on Fluorescence labeling and Determination of Polypeptide(PC2～PC6) by High Performance Liquid Chromatography
LI Jing-xi, GAO Li-jie, CAO Wei, ZHENG Li, CHEN Jun-hui, XU Xiu-li, and WANG Xiao-ru
This study was based on the thiol groups(-SH) of PC2～PC6, which could be reacted with the Monobromobimane(mBBr), in order to get polypeptide derivatives with fluorescent signal. A new method was developed for measuring the Polypeptides by high performance liquid chromatography with fluorescence detector, then the chromThis study was based on the thiol groups(-SH) of PC2～PC6, which could be reacted with the Monobromobimane(mBBr), in order to get polypeptide derivatives with fluorescent signal. A new method was developed for measuring the Polypeptides by high performance liquid chromatography with fluorescence detector, then the chromatographic conditions of HPLC was optimized;meawhile the reaction proportion of PCs and mBBr was identified by Trap-MS. The results showed that, the reaction proportion of PCs and mBBr was 1∶1, the polypeptide derivatives had good stability;the five compounds separation was better, and the peak time focused on the 16.6～22.0 min;the linear correlation coefficient of PC2, PC3, PC4, PC5 and PC6 was >0.999 1, and the limits of quantification were 0.3, 0.05, 0.3, 0.5 and 0.8 mg·L-1 respectively, the recovery rate was 83.0%～102.0%;the method was reproducible, RSD<2%, this method for measuring the peptide compounds was rapid and accurate..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3301 (2014)
Determination of Carmine in Carbonated Beverages Using 3-D Fluorescence Spectra Coupled with Second-Order Calibration Algorithm
LI Run, CHEN Guo-qing, ZHU Chun, KONG Fan-biao, and HU Yang-jun
Three-dimensional fluorescence spectra combined with second-order calibration algorithm based on alternate a weighted residual (ANWE) was applied to the direct concentration determination of carmine in carbonated beverages. Firstly, 3-D fluorescence spectra of carmine and sunset yellow mixed solutions with different coThree-dimensional fluorescence spectra combined with second-order calibration algorithm based on alternate a weighted residual (ANWE) was applied to the direct concentration determination of carmine in carbonated beverages. Firstly, 3-D fluorescence spectra of carmine and sunset yellow mixed solutions with different concentrations were obtained by employing spectrometer, and analyzed by using ANWE, the correlation coefficient between calibration concentration and the actual concentration was 0.991 7, and the average recovery was 100.92%±2.71%. The results show that the ANWE algorithm is reliable. Then, the commercial carbonated soft drinks in 8, 9, 12 and 13 times diluted concentration were detected by using ANWE algorithm, the correlation coefficient between relative concentration and the actual concentration were 0.993 0, 0.993 0, 0.993 2 and 0.793 2, respectively, and the contents of carmine in beverage were 38.88, 37.71, 37.68 and 39.65 μg·mL-1, respectively. The average concentration was (38.48±0.96) μg·mL-1. Finally, the standard addition method was applied to estimate the prediction accuracy between calibration concentration and the actual concentration was 0.993 5, and the average recovery was 102.99%±2.15%. The results can provide a new idea for the rapid content determination of food pigments in commercial beverages..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3307 (2014)
An Ultraviolet Spectroscopy Method for Rapid Partial Discharge Detection in GIS
DAI Dang-dang, WANG Xian-pei, HU Hong-hong, ZHAO Yu, LONG Jia-chuan, ZHU Guo-wei, TIAN Meng, and HUANG Yun-guang
By detecting the stable by-products of SF6 through ultraviolet spectroscopy, the present paper achieved the rapid detection of the GIS partial discharge fault. First derivative and the S-G filter were used for the spectral denoising and smoothing. The discharge experiment was used for validating feature selection. PrinBy detecting the stable by-products of SF6 through ultraviolet spectroscopy, the present paper achieved the rapid detection of the GIS partial discharge fault. First derivative and the S-G filter were used for the spectral denoising and smoothing. The discharge experiment was used for validating feature selection. Principal component regression was used for the analysis of the concentration of SO2. The concentration of SO2 was used for fuzzy judge. By selecting the appropriate wavelength range (295～305 nm), ultraviolet spectrum can identify SO2 from the complex by-products of SF6. In this paper, firstly, the author reviewed the decomposition mechanism of SF6 under partial discharge, and then verified the rationality of detecting partial discharge by UV, and ultimately achieved the rapid detection of GIS partial discharge and fuzzy judgment of discharge time..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3312 (2014)
Estimation of Heavy Metal Concentrations in Reclaimed Mining Soils Using Reflectance Spectroscopy
TAN Kun, YE Yuan-yuan, DU Pei-jun, and ZHANG Qian-qian
A selection of soil samples from reclaimed mining areas were prepared to establish the quantitative inversion models of the soil heavy metal (As, Zn, Cu, Cr, and Pb) concentrations. The concentrations of the soil heavy metals and the visible and near-infrared spectra of the soil samples were obtained in a darkroom. FirA selection of soil samples from reclaimed mining areas were prepared to establish the quantitative inversion models of the soil heavy metal (As, Zn, Cu, Cr, and Pb) concentrations. The concentrations of the soil heavy metals and the visible and near-infrared spectra of the soil samples were obtained in a darkroom. Firstly, smoothing processing was used to smooth the noise in the original spectra, and the spectral transformation techniques of first derivative (FD), continuum removal (CR), and standard normal variate (SNV) were used to promote the model stability and the accuracy of the prediction. Through correlation analysis, the feature bands of the different transformed spectra were extracted. Finally, three different inversion models were adopted and compared, i.e., traditional multiple linear regression (MLR), partial least squares regression (PLSR), and least squares support vector machines (LS-SVM) modeling. The results indicated that: (1) the stability and accuracy of the inversion models established by the different transformed spectra was high, in which LS-SVM was better than PLSR, and PLSR was better than MLR (except for a few cases);and (2) the spectral features extracted from the different transformed spectra had a certain influence on the inversion model, in which the results based on CR transformation and SNV transformation were better than the FD transformation. Therefore, the quantitative estimation of heavy metal concentrations by the use of reflectance spectroscopy is feasible, and the pre-processing is essential to improve the accuracy of the model..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3317 (2014)
Mineralogy and Colosation of Oil-Green Jadeite Jade
YIN Ke, TIAN Jian, MA Yu-bo, WU Yu, and WANG Yang
Mineralogy and coloration of oil-green jadeite jade were investigated using X-Ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD results show that “flesh” of oil-green jadeite jade is mainly composed of relatively pure jadeite, whereas the “skin”Mineralogy and coloration of oil-green jadeite jade were investigated using X-Ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD results show that “flesh” of oil-green jadeite jade is mainly composed of relatively pure jadeite, whereas the “skin” of which is dominated by jadeite, chlorite and chrysotile. The mineral constituents revealed by FTIR are fairly consistent with XRD. Three typical adsorption peaks of ~2 956, ~2 919 and ~2 850 cm-1 related to organic matters occurred in both “flesh” and “skin” of oil-green jadeite jade. Jadeite in “flesh” exhibits an obvious columnar growth and has a better crystallinity than that of “skin”. However, jadeite in “skin” is richer in magnesium than that of “flesh”, suggesting an intense water-rock reaction of jadeite in “skin”. Chrysotile just occurs in “skin” of oil-green jadeite jade, and it presents a curved crystal plane. Flaky chlorite was detected in both cracks of “flesh” and “skin”, which might be the main cause of coloration of oil-green jadeite jade. Chlorite, formed in the reducing water-rock reaction, would adsorb or wrap a certain amount of organic matters, resulting in the occurrence of the characteristic adsorptions of oil-green jadeite jade..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3323 (2014)
The Enrichment Characteristic and Mechanism of Gold-Silver Minerals in Submarine Hydrothermal Sulfides from the Ultra-Slow-Spreading SWIR
WANG Yan, SUN Xiao-ming, WU Zhong-wei, DENG Xi-guang, DAI Ying-zhi, and LIN Zhi-yong
In the present study, content and occurrence of Au, Ag in three submarine hydrothermal sulfide samples from the ultra-slow-spreading Southwest Indian Ridge (SWIR) were studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM) and energy dispersive X-ray spectIn the present study, content and occurrence of Au, Ag in three submarine hydrothermal sulfide samples from the ultra-slow-spreading Southwest Indian Ridge (SWIR) were studied by using inductively coupled plasma-atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results of ICP-AES show that all of the samples have signs of Au-Ag enrichment. By SEM/EDS, we discovered a mass of gold-silver minerals in the samples. In S27-4, gold occurs as irregular-shaped native gold and electrum grains in sulfides or between crystal particles. However, we discovered lots of Au-independent silver minerals except parts of electrum in S35-22. EDS results of silver minerals indicate that silver minerals closely related with halogen element, inferring that silver minerals may be silver halides. Electrum in S35-22 can be absorbed at the surface or crystal edge of pyrite besides occurring in or between sulfides as S27-4, supposed to be related to surface defect in pyrite. Electrum is the only Au-Ag mineral discovered in S35-17. These electrum gains occur as inclusion gold, absorbed gold or fissure gold. In addition, there are different Au-Ag mole ratios of electrum in three samples, indicating distinct hydrothermal conditions. In the base of research before, we consider that AgCl－2 is the dominant complex of silver in ore-forming fluid of S27-4, however, gold is transported as AuCl－2 transforming to AuHS0, indicating that hydrothermal fluids decreased from high-moderate to moderate-low temperature and conductive cooling played an important role in this process. Similar enrichment mechanism happened in S35-22, but silver halides discovered in S35-22 suggest a higher temperature and chloride in the early stage. However, The enrichment of electrums in black smoke sample(S35-17) relates to mixing of hydrothermal fluids and seawater..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3327 (2014)
Micro-Area Characteristics of Laminated Chert in the Volcanic Rocks of Xionger Group of Ruyang Area and Its Geological Significances
LUO An, LI Hong-zhong, ZHAO Ming-zhen, YANG Zhi-jun, LIANG Jin, and HE Jun-guo
The Xionger Group was originated from the volcanic eruption and sedimentation in Precambrian, whose sedimentary strata at the top were named Majiahe Formation. In the Majiahe Formation, there were hydrothermal chert widely distributed, which were exhibited to be interlayers in the volcanic rocks. The polarized microscoThe Xionger Group was originated from the volcanic eruption and sedimentation in Precambrian, whose sedimentary strata at the top were named Majiahe Formation. In the Majiahe Formation, there were hydrothermal chert widely distributed, which were exhibited to be interlayers in the volcanic rocks. The polarized microscope, X-ray diffraction (XRD), Raman and electron back scatter diffraction (EBSD) were conducted to study the characteristics in micro area of the jasperite samples, which were from the sedimentary interlayers in the volcanic rocks of Majiahe Formation in Xionger Group. As shown in the microphotographs and EBSD images, the quartz in the chert had small grain size, low degree of crystallinity and close packed structure, which quite agreed with the characteristics of hydrothermal sedimentary chert. In the chert of Xionger Group, there were clear banded (or lamellar) structures which were contributed by the diversities of the grain size and mineral composition. The different bands (or lamellars) had alternative appearance repeatedly, and denoted the diversities and periodic changes in the substance supply during the precipitation. According to the results of the XRD analysis, the majority minerals of the chert was low temperature quartz, whose lattice parameters were a=b=0.491 3 nm, c=0.540 5 nm and Z=3. As denoted in the EBSD image and result of Raman analysis, several impurity minerals were formed in the chert in different stages, whose geneses and formation time were quite different. The clay minerals and pyrite were scattered in distribution, and should be contributed by the original sedimentation. On contrary, the felsic minerals and mafic silicate minerals were originated from the sedimentation of tuffaceous substance during the volcanic eruption. The minerals of volcanic genesis had relatively larger grain size, and they deposited together with the hydrothermal sediments to form the bands (or lamellars) of coarse minerals. However, the hydrothermal sedimentation contributed to the bands (or lamellars) with minerals of much smaller grain size, which therefore resulted in diversities from the other bands (or lamellars). According to this, the repeated bands (or lamellars) denoted the volcanic activities were cyclic during the formation of the chert. What’s more, the carbonate vein came from the precipitation of subsequent hydrothermal fluids in the fracture of the chert, which contributed to the changes (e.g. rising in crystallinity degree of silica and formation of microstructure of new silicate) near the interface between chert and the carbonate vein. Although there were many impurity minerals with complex genesis, the relatively lower content of silica in the chert of Xionger Group was due to the volcanic mineral mainly. Since there were impurity minerals of volcanic genesis in relatively large amount, the content of silica in the chert of Xionger Group was hence relatively low. In this study, the Raman analysis was witnessed to be an effective way in the researches on the chert, and could open out the type of mineral, micro-structure and degrees of crystallinity (or order). These characteristics were well kept in the micro-area, and played significant roles to reflect and understand the formation mechanism and subsequent evolution of the chert..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3333 (2014)
Analysis of Chemical Speciation of Heavy Metals in L07-11 Profile Sediments of “Big Ear” Region of Lop Nor Lake
ZHU Xin-ping, ZHANG Liang-hui, JIANG Ping-an*, JIA Hong-tao, ZHENG Chun-xia, and FAN Shun-hui
As playa is the typical characteristic in “Big Ear” Region of Lop Nor Lake, it is significant for enriching playa heavy metal earth environmental chemical data by analyzing species distribution of heavy metal among this district. In this thesis, heavy metal Cd, Pb, Ni, Cu in L07-11 Profile Sediments of “Big Ears” RegioAs playa is the typical characteristic in “Big Ear” Region of Lop Nor Lake, it is significant for enriching playa heavy metal earth environmental chemical data by analyzing species distribution of heavy metal among this district. In this thesis, heavy metal Cd, Pb, Ni, Cu in L07-11 Profile Sediments of “Big Ears” Region of Lop Nor Lake are considered as research objects. Tessier sequential extraction and Graphite furnace atomic absorption method(GF-990) are used to discuss and analyze five forms of Cd, Pb, Ni, Cu among sediments. The results show that the content of Cd, Pb, Ni and Cu is in the range from 1.10～2.54, 9.18～20.02, 9.88～17.15, 4.43～21.11 mg·kg-1, respectively. The value of organic matter range from 8.71～54.72 g·kg-1. The order of the bioavailable state in heavy metals is Cd＞Pb＞Cu＞Ni. Pb and Cd mainly exist in exchangeable form including water-soluble, and that Ni is in residual form, and that Cu is mostly in Fe-Mn oxide bound iron-manganese oxides or in residual form. Among surface sediments, effective content of heavy metal is more than 80%. Except Cu, the content of heavy metal Cd, Pb, Ni in exchangeable form is more than 60%. Heavy metal Cd and Pb has higher secondary release potential. The content of heavy metal and organic material has some correlation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3340 (2014)
Chemical Characteristics of Nickel(Ⅱ) 2,3-Dimercaptosuccinate Complexes Modified on Gold Electrodes
LIU Wen-han, YUAN Rong-hui, and TENG Yuan-jie
2,3-Dimercaptosuccinic acid (DMSA) and its complex Nickel(Ⅱ) 2,3-Dimercaptosuccinate (DMSA-Ni(Ⅱ)) were assembled on the electrochemically activated Au electrode and the modified films were investigated by ex-situ SERS, SEM and electro-reduction. The coordination ratio (1∶2) and stability constant (4.716×107) of DM2,3-Dimercaptosuccinic acid (DMSA) and its complex Nickel(Ⅱ) 2,3-Dimercaptosuccinate (DMSA-Ni(Ⅱ)) were assembled on the electrochemically activated Au electrode and the modified films were investigated by ex-situ SERS, SEM and electro-reduction. The coordination ratio (1∶2) and stability constant (4.716×107) of DMSA and Nickel(Ⅱ) were firstly confirmed by UV. Then, the SERS spectra showed that DMSA was absorbed on the surface of activated Au and the coordinate bond of DMSA-Ni(Ⅱ) was existed as S—Ni—O. Meanwhile, two reduction peaks of DMSA-Ni(Ⅱ) on Au electrode were presented at negative potential. The first peak (from positive to negative values) was related to the RS—Au group which was produced by the mutual absorption of DMSA and Au. The second reduction peak was related to Nickel(Ⅱ). Finally, it was further confirmed by calculating the surface coverage and comparison of molecular area. And it was found that the molecular arrangement of DMSA-Ni(Ⅱ) on Au electrode generated as monolayer which was dispersed or connected partly instead of concentrated or overlapped..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3345 (2014)
Preparation and Optimum Process of Walnut Peel Activated Carbon by Zinc Chloride as Activating Agent
LIU Xiao-hong, WANG Xing-wei, ZHAO Bo, Lv Jun-fang, KANG Ni-na, and ZHANG Yao-jun
Walnut peel as raw material, zinc chloride was used as activating agent for preparation walnut peel activated carbon in the muffle furnace in this experiment, using orthogonal design. Yield, the specific surface area and iodine number of walnut peel activated carbon were determined at all designed experimental conditioWalnut peel as raw material, zinc chloride was used as activating agent for preparation walnut peel activated carbon in the muffle furnace in this experiment, using orthogonal design. Yield, the specific surface area and iodine number of walnut peel activated carbon were determined at all designed experimental conditions and the optimum technological condition of preparation was obtained. By analysis of aperture, infrared spectra and the content of acidic group in surface with Boehm, walnut peel activated carbon of prepared at the optimum condition was characterized. The results showed the optimum technological parameters of preparation: activation temperature (600 ℃), activation time (1h), the concentration of zinc chloride (50%), the particle size( 60 mesh). The specific surface area of walnut peel activated carbon obtained at optimum condition was mounting to 1 258.05 m2·g-1 , the ratio of medium porous 32.18%. Therefore, walnut peel can be used in the preparation of the high-quality activated carbon of large surface area. Agricultural wastes, as walnut peel, not only were implemented recycle, but also didn’t make any pollution. Meanwhile, a cheap adsorbent was provided and it was of great significance to open a new source of activated carbon..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3350 (2014)
Research on a Novel High-Precision Methane Concentration Detection System
SONG Lin-li, ZHOU Han-chang, and ZHANG Zhi-jie
In the gas concentration detection process using the characteristic spectrum absorption method, in order to improve the detection accuracy of the gas concentration, it often has to use the high-quality narrowband modulated laser and modulate wavelength to align with the characteristic absorption peaks of measured gas. In the gas concentration detection process using the characteristic spectrum absorption method, in order to improve the detection accuracy of the gas concentration, it often has to use the high-quality narrowband modulated laser and modulate wavelength to align with the characteristic absorption peaks of measured gas. But by this way, the cost of the laser and system requirements will be greatly increased. To use the existing portable, low-cost semiconductor laser conditions, at the same time it can obtain higher precision, conversion window differential absorption optical structure and the algorithm of differential characteristic absorption ratio was designed. Selection reason of position of the wavelength characteristic was analyzed, and steps to implement the processing algorithm were given. Systematically utilizing the combination method of conversion window and absorption gas chamber, by the method for calculating the ratio of the light intensity response, the light intensity from non-characteristic absorption peak position was divided out. So it achieved a similar detecting effect was achieved that used a narrow-band laser aligned to the feature absorption peak position. Experiments adopted MW-IR-1650 infrared laser, type SSM17-2 stepper motor control module, C30659 infrared detectors, and other devices. In the experiments, different concentrations of methane gas were tested, and experimental results show that the relative error of measurement was less than 2.0% within the range from 200 to 5 000 ppm. In summary, it’s proved that the system has high accuracy and stability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3354 (2014)
Mahalanobis Distance Based Hyperspectral Characteristic Discrimination of Leaves of Different Desert Tree Species
LIN Hai-jun, ZHANG Hui-fang, GAO Ya-qi, LI Xia, YANG Fan, and ZHOU Yan-fei
The hyperspectral reflectance of Populus euphratica, Tamarix hispida, Haloxylon ammodendron and Calligonum mongolicum in the lower reaches of Tarim River and Turpan Desert Botanical Garden was measured by using the HR-768 field-portable spectroradiometer. The method of continuum removal, first derivative reflectance anThe hyperspectral reflectance of Populus euphratica, Tamarix hispida, Haloxylon ammodendron and Calligonum mongolicum in the lower reaches of Tarim River and Turpan Desert Botanical Garden was measured by using the HR-768 field-portable spectroradiometer. The method of continuum removal, first derivative reflectance and second derivative reflectance were used to deal with the original spectral data of four tree species. The method of Mahalanobis Distance was used to select the bands with significant differences in the original spectral data and transform spectral data to identify the different tree species. The progressive discrimination analyses were used to test the selective bands used to identify different tree species. The results showed that The Mahalanobis Distance method was an effective method in feature band extraction. The bands for identifying different tree species were most near-infrared bands. The recognition accuracy of four methods was 85%, 93.8%, 92.4% and 95.5% respectively. Spectrum transform could improve the recognition accuracy. The recognition accuracy of different research objects and different spectrum transform methods were different. The research provided evidence for desert tree species classification, monitoring biodiversity and the analysis of area in desert by using large scale remote sensing method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3358 (2014)
A Dual-Band Algorithm to Detect Contaminants with Low Visibility on Chicken Carcass Surface
WU Wei, CHEN Gui-yun, XIA Jian-chun, YE Chang-wen, and CHEN Kun-jie
A novel dual-band algorithm for detecting contaminants with low visibility on chicken carcass surface based on hyperspectral image was proposed. Firstly, The 675 nm band image, in which the identity of the intensity within ROI (Region of Interest)is the best and the spectrum difference between ROI and the edge of the RA novel dual-band algorithm for detecting contaminants with low visibility on chicken carcass surface based on hyperspectral image was proposed. Firstly, The 675 nm band image, in which the identity of the intensity within ROI (Region of Interest)is the best and the spectrum difference between ROI and the edge of the ROI is the biggest, was chosen from the hyperspectral data for binarization and the mask was extracted by using region growing on the biggest connected area. Then the “and” operation between the mask and the 400 nm band image with the largest discriminability of contaminants was carried out. The max ROI which can self adapt according to the position and shape of the chicken carcass was obtained. Finally, the labeling method was used to recognize if there are contaminations within the segmented ROI. The results showed that through the proposed method, the max ROIs which could self adapt to the position and shape of the chicken carcass were extracted and the average size of the ROI was bigger than 176% compared to that by existing methods. The average correct identification rate of contaminations such as blood, bile and feces was 81.6%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3363 (2014)
Research on Signal Processing for Water Quality Monitoring Based on Continuous Spectral Analysis
WEI Kang-lin, CHEN Ming, WEN Zhi-yu, and XIE Yin-ke
Based on continuous spectrum analysis, the mathematical model for spectrum signal was established. And the spectrum signal’s systematic error processing method based on the invariance of the ratio of the light intensities at any two wavelengths in the range of continuous spectrum was put forward. Combined with wavelet Based on continuous spectrum analysis, the mathematical model for spectrum signal was established. And the spectrum signal’s systematic error processing method based on the invariance of the ratio of the light intensities at any two wavelengths in the range of continuous spectrum was put forward. Combined with wavelet multi-resolution filtering noise processing techniques, the background interference processing method was established based on the spectral characteristics of the measured water quality parameter. These signal processing methods were applied to our independently developed multi-parameter water quality monitoring instrument to on-line measure COD (chemical oxygen demand), six valence chromium and anionic surfactant in the normative and actual environmental water samples, and the monitoring instrument had good repeatability (10%) and high accuracy (±10%) to meet the technical requirements of national environmental protection standards, which was verified by the contrast experiment with China national standard analysis method for determination of the three water quality parameter. The results showed that the researched signal processing methods were able to effectively reduce the spectrum signal’s systematic error and the interference from noise and background, which was very important to improve the water quality monitoring instrument’s technical function..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3368 (2014)
Two-Temperature Diagnostic Studies by Emission Spectra for Nonequilibrium Ti-H Plasma
DENG Chun-feng, LU Biao, WU Chun-lei, WANG Yi-fu, and WEN Zhong-wei
Using the T-H solid solution made by titanium absorbed hydrogen as the cathode, the Ti-H plasma produced by the pulsed vacuum arc ion source was nonequilibrium: it contained both the component of titanium and hydrogen;there existed gradient in the radiaL, the horizontal and the time. As a result, it could not be descriUsing the T-H solid solution made by titanium absorbed hydrogen as the cathode, the Ti-H plasma produced by the pulsed vacuum arc ion source was nonequilibrium: it contained both the component of titanium and hydrogen;there existed gradient in the radiaL, the horizontal and the time. As a result, it could not be described by a single temperature. The present paper assumed that the subsystem consisting of electrons and the subsystem consisting of other heavy particles reached equilibrium respectively, meaning that the Ti-H plasma was described by the two temperatures as electron temperature and heavy ion temperature, it was non-equilibrium two-temperature plasma. Using Culdberg-Waage dissociation equation to describe the molecular dissociation process in the system, using Saha ionization equation to describe the atomic ionization process, combining plasma’s charge quasi-neutral condition and introducing atomic emission spectroscopy as a plasma diagnostic method which would not interfere the plasma at the same time;the temperature and the particle number density of the Ti-H plasma were diagnosed. Using MATLAB as a tool, both the titanium atoms and monovalent titanium ions’ ionization were considered, and the calculated results showed that with the electtron density determined by the Stark broadening of spectral lines in advance, except the heavy particle temperature and the hydrogen number density, the Ti-H plasma’s parameters could be diagnosed fairly accurately;the accuracy of the electron density values had a great effect on the calculation results;if the heavy particle temperature could be determined in advance, the temperature and the particle number density of the Ti-H plasma could be accurately analyzed quantitatively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3374 (2014)
Research on Density Detection in Dendrocalamus Farinosus Based on Computer Tomography
SHAN Hai-bin, LIU Xing-e, YANG Shu-min, YANG Xi, TIAN Gen-lin, and ZHAO De-da
Density is one of the important physical indicators of bamboo, associated with its many physical and mechanical properties. The temporal and spatial variation of density in 2-5-year-old Dendrocalamus farinosus were measured using computed tomography (CT) technology. Scanning parameters were obtained through orthogonal Density is one of the important physical indicators of bamboo, associated with its many physical and mechanical properties. The temporal and spatial variation of density in 2-5-year-old Dendrocalamus farinosus were measured using computed tomography (CT) technology. Scanning parameters were obtained through orthogonal design. The relationship of air-dry density (Y) and the corresponding CT values (X) was established and verified through regression analysis, which presents an approximate linear relationship between them. The linear equation is Y=0.001X+1.148. The radial and longitudinal variation of density was determined by the regression model. This study provides a new method to measure bamboo density efficiently and accurately, and also put forward a new thought to further study structure and characteristics of bamboo..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3380 (2014)
Estimation of Vegetation Water Content from Landsat 8 OLI Data
ZHENG Xing-ming, DING Yan-ling, ZHAO Kai, JIANG Tao, LI Xiao-feng, ZHANG Shi-yi, LI Yang-yang, WU Li-li, SUN Jian, REN Jian-hua, and ZHANG Xuan-xuan
The present paper aims to analyze the capabilities and limitations for retrieving vegetation water content from Landsat8 OLI (Operational Land Imager) sensor-new generation of earth observation program. First, the effect of soil background on canopy reflectance and the sensitive band to vegetation water content were anThe present paper aims to analyze the capabilities and limitations for retrieving vegetation water content from Landsat8 OLI (Operational Land Imager) sensor-new generation of earth observation program. First, the effect of soil background on canopy reflectance and the sensitive band to vegetation water content were analyzed based on simulated dataset from ProSail model. Then, based on vegetation water indices from Landsat8 OLI and field vegetation water content during June 1 2013 to August 14 2013, the best vegetation water index for estimating vegetation water content was found through comparing 12 different indices. The results show that: (1) red, near infrared and two shortwave infrared bands of OLI sensor are sensitive to the change in vegetation water content, and near infrared band is the most sensitive one;(2) At low vegetation coverage, solar radiation reflected by soil background will reach to spectral sensor and influence the relationship between vegetation water index and vegetation water content, and simulation results from ProSail model also show that soil background reflectance has a significant impact on vegetation canopy reflectance in both wet and dry soil conditions, so the optimized soil adjusted vegetation index (OSAVI) was used in this paper to remove the effect of soil background on vegetation water index and improve its relationship with vegetation water content;(3) for the 12 vegetation water indices, the relationship between MSI2 and vegetation water content is the best with the R-square of 0.948 and the average error of vegetation water content is 0.52 kg·m-2;(4) it is difficult to estimate vegetation water content from vegetation water indices when vegetation water content is larger than 2 kg·m-2 due to spectral saturation of these indices..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3385 (2014)
Estimating Canopy Water Content in Wheat Based on New Vegetation Water Index
CHENG Xiao-juan, YANG Gui-jun, XU Xin-gang, CHEN Tian-en, LI Zhen-hai, FENG Hai-kuan, and WANG Dong
Moisture content is an important indicator for crop water stress condition, timely and effective monitoring crop water content is of great significance for evaluate crop water deficit balance and guide agriculture irrigation. In order to improve the saturated problems of different forms of typical NDWI (Normalized DiffMoisture content is an important indicator for crop water stress condition, timely and effective monitoring crop water content is of great significance for evaluate crop water deficit balance and guide agriculture irrigation. In order to improve the saturated problems of different forms of typical NDWI (Normalized Different Water Index), we tried to introduce EVI(Enhanced Vegetation Index) to build new vegetation water indices(NDWI#) to estimate crop water content. Firstly, PROSAIL model was used to study the saturation sensitivity of NDWIs and NDWI# to canopy water content and LAI(Leaf Area Index). Then, the estimated model and verified model were estimated using the spectral data and moisture data in the field. The result showed that the new indices have significant relationships with canopy water content . In particular, by implementing modified standardized for NDWI1 450, NDWI1 940, NDWI2 500. The result indicated that newly developed indices with visible-infrared and shortwave infrared spectral feature may have greater advantage for estimation winter canopy water content..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3391 (2014)
Laser Induced Breakdown Spectra of Coal Sample and Self-Absorption of the Spectral Line
ZHANG Gui-yin, JI Hui, and JIN Yi-dong
The LIBS of one kind of household fuel coal was obtained with the first harmonic output 532 nm of an Nd·YAG laser as radiation source. With the assignment of the spectral lines, it was found that besides the elements C, Si, Mg, Fe, Al, Ca, Ti, Na and K, which are reported to be contained in coal, the presented samThe LIBS of one kind of household fuel coal was obtained with the first harmonic output 532 nm of an Nd·YAG laser as radiation source. With the assignment of the spectral lines, it was found that besides the elements C, Si, Mg, Fe, Al, Ca, Ti, Na and K, which are reported to be contained in coal, the presented sample also contains trace elements, such as Cd, Co, Hf, Ir, Li, Mn, Ni, Rb, Sr, V, W, Zn, Zr etc, but the spectral lines corresponding to O and H elements did not appear in the spectra. This is owing to the facts that the transition probability of H and O atoms is small and the energy of the upper level for transition is higher. The results of measurement also show that the intensity of spectral line increases with the laser pulse energy and self-absorption of the spectral lines K766.493 nm and K769.921 nm will appear to some extent. Increasing laser energy further will make self-absorption more obvious. The presence of self-absorption can be attributed to two factors. One is the higher transition rate of K atoms, and the other is that the increase in laser intensity induces the enhancement of the particle number density in the plasma..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3397 (2014)
Analysis of Different Types of Soil by FTIR and ICP-MS
ZHAO Shuai-qun, LIU Gang, OU Quan-hong, XU Juan, REN Jing, and HAO Jian-ming
Fourier transform infrared spectroscopy (FTIR) and inductively coupled plasma mass spectrometry (ICP-MS) were used to study six types of farmland soil from different areas. The FTIR results showed that the infrared spectra of soil were mainly composed of the absorption band of clay minerals, organic matter and inorganiFourier transform infrared spectroscopy (FTIR) and inductively coupled plasma mass spectrometry (ICP-MS) were used to study six types of farmland soil from different areas. The FTIR results showed that the infrared spectra of soil were mainly composed of the absorption band of clay minerals, organic matter and inorganic salts, such as carbonate, phosphate, manganate and so on. The mineral atlas of six soil samples were all of montmorillonite type. The ICP-MS test results showed that the available elements content of different types and colours of soil samples were different. There was significant lack status of available Ca between different types of farmland soil, the content of available Mg in Huludao soil was in the medium level, other areas were in the status of shortage. There was only significant lack status of available Mn and available Zn in Baiyin soil, the content of available Fe in Chenggong soil was in the status of shortage, the content of available Cu in all areas was particularly rich. The content of available P in Jining soil was rich, Luoyang and Huludao soil were in the medium level, the soil of Chenggong, Baiyin and Luliang were in the status of shortage. The content of available K in Luoyang, Chenggong and Jining soil was relatively rich, Luliang soil was in the medium level, the soil of Huludao and Baiyin were in the status of shortage. It is observed that the deeper the color of soil samples, the richer the amount of some available trace elements such as magnesium, copper, iron, manganese and zinc. According to the national classification standard of available elements content, we analyzed the nutrients of available elements content in the farmland soil of different areas, and implemented remedial measures for the lacking of available elements for all of the six areas..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3401 (2014)
Determination of Chlorine in Gasoline by Inductively Coupled Plasma Atomic Emission Spectrometry
ZHAO Yan, CHEN Xiao-yan, XU Dong-yu, ZHANG Shi-yuan, and CHEN Ze-yong
A new method was studied for the analysis of chlorine in gasoline by inductively coupled plasma atomic emission spectrometry (ICP-AES). Samples werediluted 1+4(φ) with kerosene. The intense spectral line for chlorine (134.724 nm) was used. In order to eliminate carbon and maintain stable plasma, small amounts of oxygenA new method was studied for the analysis of chlorine in gasoline by inductively coupled plasma atomic emission spectrometry (ICP-AES). Samples werediluted 1+4(φ) with kerosene. The intense spectral line for chlorine (134.724 nm) was used. In order to eliminate carbon and maintain stable plasma, small amounts of oxygen (0.050 L·min-1) were added to the auxiliary gas. The instrumental main condition was optimized in terms of effects of generator power, nebulizer gas flow, auxiliary gas flow, and oxygen flow on SBR for chlorine. Standard addition method was used to compensate matrix effect and signal drift. The recovery for spiking gasoline samples and the limit of detection were in the range of 96.6％～103.9％ and 0.27 mg·L-1 respectively. The relative standard deviation (RSD) was between 1.57% and 4.49%. Compared with microcoulometry, the analysis results of organic chlorine were basically the same. Moreover, chlorine content, including organic chlorine and inorganic chloride was determined by ICP-AES. The proposed method had the advantages of simplicity, speediness and sensitivity, and expanded the ICP-AES application in non-metals especially halogen elements. It can be used for the analysis of chlorine in gasoline and provides technical support for quality evaluation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3406 (2014)
Study on the Vibrational Spectra and XRD Characters of Huanglong Jade from Longling County, Yunnan Province
PEI Jing-cheng, FAN Lu-wei, and XIE Hao
Based on the conventional test methods, the infrared absorption spectrum, Raman spectrum and X-ray diffraction (XRD) were employed to study the characters of the vibration spectrum and mineral composition of Huanglong jade. The testing results show that Huanglong jade shows typical vibrational spectrum characteristics Based on the conventional test methods, the infrared absorption spectrum, Raman spectrum and X-ray diffraction (XRD) were employed to study the characters of the vibration spectrum and mineral composition of Huanglong jade. The testing results show that Huanglong jade shows typical vibrational spectrum characteristics of quartziferous jade. The main infrared absorption bands at 1 162, 1 076, 800, 779, 691, 530 and 466 cm-1 were induced by the asymmetric stretching vibration, symmetrical stretching vibration and bending vibration of Si-O-Si separately. Especially the absorption band near 800 cm-1 is split, which indicates that Huanglong jade has good crystallinity. In Raman spectrum, the main strong vibration bands at 463 and 355 cm-1 were attributed to bending vibration of Si—O—Si. XRD test confirmed that Quartz is main mineral composition of Huanglong jade and there is a small amount of hematite in red color samples which induced the red color of Huanglong jade. This is the first report on the infrared, Raman and XRD spectra feature of Huanglong jade. It will provide a scientific basis for the identification, naming and other research for huanglong jade..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3411 (2014)
Characterization of Biochar by X-Ray Photoelectron Spectroscopy and 13C Nuclear Magnetic Resonance
XU Dong-yu, JIN Jie, YAN Yu, HAN Lan-fang, KANG Ming-jie, WANG Zi-ying, ZHAO Ye, and SUN Ke
The wood (willow branch) and grass (rice straw) materials were pyrolyzed at different temperatures (300, 450 and 600 ℃) to obtain the biochars used in the present study. The biochars were characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS) and solid state 13C cross-polarization and magic angThe wood (willow branch) and grass (rice straw) materials were pyrolyzed at different temperatures (300, 450 and 600 ℃) to obtain the biochars used in the present study. The biochars were characterized using elementary analysis, X-ray photoelectron spectroscopy (XPS) and solid state 13C cross-polarization and magic angle spinning nuclear magnetic resonance spectroscopy (13C NMR) to illuminate the structure and composition of the biochars which were derived from the different thermal temperatures and biomass. The results showed that the H/C, O/C and (O+N)/C ratios of the biochars decreased with the increase in the pyrolysis temperatures. The surface polarity and ash content of the grass-derived biochars were higher than those of the wood-derived biochars. The minerals of the wood-derived biochars were mainly covered by the organic matter;in contrast, parts of the mineral surfaces of the grass-derived biochars were not covered by organic matter. The 13C NMR of the low temperature-derived biochars revealed a large contribution of aromatic carbon, aliphatic carbon, carboxyl and carbonyl carbon, while the high temperature-derived biochars contained a large amount of aromatic carbon. Moreover, the wood-derived biochars produced at low heat treatment temperatures contained more lignin residues than grass-derived ones, probably due to the existence of high lignin content in the feedstock soures of wood-derived biochars. The results of the study would be useful for environmental application of biochars..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3415 (2014)
Advances in Infrared Spectrum Zoom Imaging System Research
BAI Yu, XING Ting-wen, and JIANG Ya-dong
Compared with the infrared spectrum fixed focal length system and infrared spectrum dual-zoom system, infrared spectrum continuous zoom imaging system which has continuous variational field of view can track targets sequentially, so it is a research direction in infrared spectrum imaging technology.Some new technologieCompared with the infrared spectrum fixed focal length system and infrared spectrum dual-zoom system, infrared spectrum continuous zoom imaging system which has continuous variational field of view can track targets sequentially, so it is a research direction in infrared spectrum imaging technology.Some new technologies are presented overseas in order to improve the detection performance, reduce cost and have good athermalized performance in infrared spectrum continuous zoom imaging system.Infrared material, infrared detector and variable aperture, those new technologies are su mmarized and the idiographic application of those new technologies in infrared spectrum continuous zoom imaging system are presented in the paper, for example athermalization of an infrared spectrum zoom lens system with new infrared material for target detection, dual band infrared spectrum continuous zoom imaging system with mid-wave infrared and long-wave infrared, infrared spectrum continuous zoom imaging system with high ratio, nfrared spectrum continuous zoom imaging system with dual F/number. It is useful for the development of chinese infrared continuous zoom imaging system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3419 (2014)
Laser-Based Radiometric Calibration
LI Zhi-gang, and ZHENG Yu-quan
Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physIncreasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the development of aerospace, atmospheric physics, spectroscopy, biological science and so on in the fields of research and industry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3424 (2014)
On-Orbit Radiometric Calibration Accuracy of FY-3A MERSI Thermal Infrared Channel
XU Na, HU Xiu-qing, CHEN Lin, ZHANG Yong, HU Ju-yang, and SUN Ling
Accurate satellite radiance measurements are significant for data assimilations and quantitative retrieval applications. In the present paper, radiometric calibration accuracy of FungYun-3A (FY-3A) Medium Resolution Spectral Imager (MERSI) thermal infrared (TIR) channel was evaluated based on simultaneous nadir observaAccurate satellite radiance measurements are significant for data assimilations and quantitative retrieval applications. In the present paper, radiometric calibration accuracy of FungYun-3A (FY-3A) Medium Resolution Spectral Imager (MERSI) thermal infrared (TIR) channel was evaluated based on simultaneous nadir observation (SNO) intercalibration method. Hyperspectral and high-quality measurements of METOP-A/IASI were used as reference. Assessment uncertainty from intercalibration method was also investigated by examining the relation between BT bias against four main collocation factors, i.e. observation time difference, view geometric difference related to zenith angles and azimuth angles, and scene spatial homogeneity. It was indicated that the BT bias is evenly distributed across the collocation variables with no significant linear relationship in MERSI IR channel. Among the four collocation factors, the scene spatial homogeneity may be the most important factor with the uncertainty less than 2% of BT bias. Statistical analysis of monitoring biases during one and a half years indicates that the brightness temperature measured by MERSI is much warmer than that of IASI. The annual mean bias (MERSI-IASI) in 2012 is (3.18±0.34)K. Monthly averaged BT biases show a little seasonal variation character, and fluctuation range is less than 0.8K. To further verify the reliability, our evaluation result was also compared with the synchronous experiment results at Dunhuang and Qinghai Lake sites, which showed excellent agreement. Preliminary analysis indicates that there are two reasons leading to the warm bias. One is the overestimation of blackbody emissivity, and the other is probably the incorrect spectral respond function which has shifted to window spectral. Considering the variation character of BT biases, SRF error seems to be the dominant factor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3429 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 1 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 12, 3436 (2014)
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