Journals >Spectroscopy and Spectral Analysis
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2018
Volume: 38 Issue 9
52 Article(s)
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Trend Analysis of Raman Application in Cultural Relics and Archaeological Research
SHEN Da-wa, ZHENG Fei, WU Na, ZHANG Yi-chi, and WANG Zhi-liang
Based on literature study, development trends of Raman spectra applied in the research area of cultural relics and archaeology was analyzed. 992 literatures published in the last forty years in the area of analyzing cultural relics and archaeological samples with Raman method were retrieved from SCI/SSCI database, and Based on literature study, development trends of Raman spectra applied in the research area of cultural relics and archaeology was analyzed. 992 literatures published in the last forty years in the area of analyzing cultural relics and archaeological samples with Raman method were retrieved from SCI/SSCI database, and 160 Chinese literatures were retrieved from CNKI database. The year distribution, journal distribution, institution distribution and cooperation of institutions, cited frequency were analyzed with literature metrology methods. The results showed that after 2000, the amount of Raman literatures related to cultural relics and archaeology increased significantly not only abroad but also in China. But there is still gap between China and other countries in amount of publication as well as cited frequency and so on. It also could be found from the analysis results that, for Raman applied in cultural relics and archaeology, there is extensive cooperation between institutions and countries. These results could be helpful to enhance the application of Raman method in the research of cultural relics and archaeology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2657 (2018)
The Theoretical Study of Anharmonic Vibrational Spectra of HOI
CHEN Heng-jie, WANG Quan-wu, ZHANG Jia-wei, and WANG Jun
The structure of the HOI molecule was optimized at first, by employing the coupled cluster theory (CC) with single, double, and perturbative triple excitations (CCSD(T)), the iterative triple excitations (CC3) and its variants (CCSDT-3), and the B3LYP method from the density functional theory (DFT) in conjunct with theThe structure of the HOI molecule was optimized at first, by employing the coupled cluster theory (CC) with single, double, and perturbative triple excitations (CCSD(T)), the iterative triple excitations (CC3) and its variants (CCSDT-3), and the B3LYP method from the density functional theory (DFT) in conjunct with the Dunning’s correlation consistent basis sets aug-cc-pVxZ/aug-cc-pVxZ-PP(x=T, Q, 5). Then, a series of discrete potential energy points were extracted nearby the equilibrium structure, which have been fitted to fourth-order polynominal expansion force field in normal coordinate. In addition, the anharmonic vibrational analysis were performed by the vibrational self-consistent field (VSCF), the vibrational configuration interaction (VCI) and the second-order vibrational perturbation theory (VPT2), the fundamental, overtone and combination (v1+v2+v3＝3), the rotational constants, the vibrational-rotational interaction constants, anharmonic constants, centrifugal distortion constants have been expected, the oscillator strength has been evaluated, and the effect of Deuterium substitution was investigated. The results show that: first, the present calculated values are in good agreement with available experimental results, spectroscopic constants from coupled cluster theory (CC) are more reliable than DFT, the deviation from DFT is obviously large, but it is quite consistent with the vibrational frequencies between CC and DFT; Second, it is not the larger basis set that causes the better coincidence between calculations and experiments, in general, the CC3 and CCSDT-3 results are more credible. Third, there is no resonance occurred in HOI or DOI..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2665 (2018)
Study on the Deposition and Optical Properties of GaN Films at Quartz Substrate
ZHANG Dong, ZHAO Yan, SONG Shi-wei, LI Yu-cai, WANG Jian, BI Xiao-guo, GAO Jing, and WANG Chun-sheng
The GaN thin film materials are widely used in light-emitting diode (LED), laser diode (LD) and other optoelectronic devices. But the preparation and application of GaN based device depends largely on its manufacturing cost. At present, because the single crystal sapphire crystal substrate has been merited, the GaN filThe GaN thin film materials are widely used in light-emitting diode (LED), laser diode (LD) and other optoelectronic devices. But the preparation and application of GaN based device depends largely on its manufacturing cost. At present, because the single crystal sapphire crystal substrate has been merited, the GaN film are commonly deposited on the single crystal sapphire substrate to achieve the high quality GaN films. And because single crystal sapphire substrate is expensive, the GaN devices is limited to use. How to directly deposit high quality GaN films on the cheap substrate and which one meets the requirements of the device have becomed the research hotspot. Quartz glass is cheap as the substrate, but it is not crystal, and it is difficult to deposite high quality thin film samples on quartz glass substrate. In this study, the preparation of GaN thin film materials was prepared by using plasma enhanced metal organic chemical vapor deposition method to change the nitrogen reaction source under normal non-stereotyped quartz substrate at the low-temperature deposition. This research adopts the in-situ reflective high energy electron diffraction spectrum (RHEED), X-ray diffraction spectrum (XRD), Transmission Spectra at room temperature (Transmission Spectra) and room TPS to spectroscopy (PL) to analysis the as-grown GaN films. The results show that the as-grown GaN films show the excellent quality crystallization and optical performance under the proper N2 flux deposition parameters..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2672 (2018)
The Luminescence Characteristics of Alumina Ceramic Powder by the Low Temperature Combustion Synthesis
HUANG Huan-huan, WANG Qian, WU Li, and LI Meng-xiao
α-Al2O3∶C crystals possess high thermoluminescence (TL) sensitivity and have been widely used as thermoluminescence dosimeters, however, α-Al2O3∶C crystals dosimeter’s shape is not easy to process, the crystals growth requires sophisticated laboratories, high temperatures and highly reducing atmosphere and their manufaα-Al2O3∶C crystals possess high thermoluminescence (TL) sensitivity and have been widely used as thermoluminescence dosimeters, however, α-Al2O3∶C crystals dosimeter’s shape is not easy to process, the crystals growth requires sophisticated laboratories, high temperatures and highly reducing atmosphere and their manufacturing cost is high. Furthermore, carbon is difficult to dope evenly in crystals. In this paper, flaky α-Al2O3∶C ceramic powder with uniform dispersion and few clusters are prepared by using the low temperature combustion synthesis method, with aluminum nitrate as reactant, urea as dye, anhydrous ethanol as solvent. We have investigated the influence of ignition temperature and annealing temperature on photoluminescence (PL) as well as TL characteristics of α-Al2O3∶C ceramic powder and discussed the TL dose response. Through analyzing the photoluminescence spectra of α-Al2O3∶C ceramic powders, it was found that the emission wavelength of α-Al2O3∶C ceramic powder is about 395 nm. When the ignition temperature T≤800 ℃, the PL intensity of α-Al2O3∶C ceramic powder reaches a maximum value at ignition temperature of 500 ℃. At the same ignition temperature T=500 ℃, α-Al2O3∶C ceramic powders were prepared by annealing at different temperatures. The results show that α-Al2O3∶C ceramic powder prepared at the ignition temperature of 500 ℃ has the greatest PL intensity after annealing at 1 000 ℃. Through the analysis on the thermoluminescence curve of α-Al2O3∶C ceramic powder, it can be seen that the sample annealed at 900 ℃ has the greatest TL glow peak at ～200 ℃. The dose response curve is made for the sample annealed at 900 ℃ by peak height method through selecting the dominant thermoluminescence peak at about 200 ℃. It was found that the TL response of the α-Al2O3∶C ceramic powders annealed at 900 ℃ shows excellent linear characteristic within a dose range of 1～50 Gy, but shows super-linear behavior in a dose range of 50～200 Gy. Compared with α-Al2O3∶C crystal (1～10 Gy) and porous alumina membranes (1～10 Gy), TL response of α-Al2O3∶C ceramic powder shows a wider range of linear dose response. This study will provide a way to improve the thermoluminescence properties of alumina ceramic powder..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2676 (2018)
Structure and Optical Properties of YAG∶Ce3+, Mn+(Mn+=Ca2+, Gd3+) Nano-Phosphor
XIA Li-bin, WANG Ling, WANG Lin-sheng, YOU Wei-xiong, XIE Jing-bing, and LI Zi-cheng
The shortage for red-light of current commercial white-light LED due to a single yellow-light emitting of YAG∶Ce3+ phosphor restricts its development and application. Ce3+, Ca2+, Gd3+ doped respectively YAG Nano-phosphors in the paper were obtained by using sol-gel method. The phase composition, structure, morphology, The shortage for red-light of current commercial white-light LED due to a single yellow-light emitting of YAG∶Ce3+ phosphor restricts its development and application. Ce3+, Ca2+, Gd3+ doped respectively YAG Nano-phosphors in the paper were obtained by using sol-gel method. The phase composition, structure, morphology, particle size, luminescence properties as well as internal quantum efficiency and mechanism of the phosphors with different ions doping content were thoroughly investigated. The particle size of phosphors was 100～200 nm. Pure YAG was obtained as doping Ce3+ and Gd3+, however, the crystal structures expand and X-ray diffractive peaks shifted toward small angles. The crystallinity of samples had no obvious variation with increasing Ce3+ and Ca2+(<0.025 mol) contents, but decreased with increasing Gd3+. The crystal field energy and degree of crystal field split for 5d state of Ce3+ increased with increasing all ions doping contents, and excitation, emission spectra of Gd series phosphors had red shift, whereas Ce, Ca series were negligible due to small doping contents. The photoluminescence (PL) intensity first increased and then decreased with increasing Ce3+ doping contents, and the optimize content was 0.06 mol. However, the PL intensity decreased gradually with the increase of Gd3+ doping contents, but decreased dramatically as increasing Ca2+ contents. The crystal structure was destroyed and PL intensity was close to zero as Ca2+ content run up to 0.03 mol, and impure phases of YAM and YAP produced. The research will provide a theoretical basis and practical reference for the further development and application of nano-YAG phosphors and related functional materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2681 (2018)
Review of Terahertz Time Domain and Frequency Domain Spectroscopy
CAO Can, ZHANG Zhao-hui, ZHAO Xiao-yan, ZHANG Han, ZHANG Tian-yao, and YU Yang
In recent years, terahertz wave has attracted much attention and interest from the scientific community because of its important theoretical research value and broad application prospects. Terahertz spectroscopy is one of the main directions of terahertz scientific development, which is divided into two types: frequencIn recent years, terahertz wave has attracted much attention and interest from the scientific community because of its important theoretical research value and broad application prospects. Terahertz spectroscopy is one of the main directions of terahertz scientific development, which is divided into two types: frequency domain spectrum and time domain spectrum. Its appearance has solved the problem of producing broadband radiation source in terahertz band, and made the terahertz fault in spectroscopy to be filled. With the development of this technology, the research about the radiation characteristics of terahertz has been gradually extended to the biomedicine, materials science, communication science, security inspection fields and so on. This paper compares the two kinds of spectrum from the production principle, performance characteristics and application ,and it introduces in detail the advantages and disadvantages as well as the superiority in some research fields of two kinds of terahertz spectrum..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2688 (2018)
Study on Terahertz and Infrared Characteristic Absorption Spectra of Solid-State Fructose
SONG Chao, DING Ling, and FAN Wen-hui
As a simple ketonic monosaccharide, fructose can be found in honey and many plants. Along with glucose and galactose, fructose is one of the three dietary monosaccharides and is usually bonded to glucose to form the disaccharide sucrose. Pure fructose is white crystal at room temperature and has been widely used in theAs a simple ketonic monosaccharide, fructose can be found in honey and many plants. Along with glucose and galactose, fructose is one of the three dietary monosaccharides and is usually bonded to glucose to form the disaccharide sucrose. Pure fructose is white crystal at room temperature and has been widely used in the food industry due to its high sweetness and low glycemic index. So far, studies on terahertz (THz) and infrared (IR) characteristics absorption spectra of the solid-state fructose are mostly confined to the simple measurement or theoretical calculation based on isolated-molecules calculation. Therefore, the THz spectra and IR spectra of solid-state fructose have been studied theoretically and experimentally in this paper. We reported the experimental absorption features of solid-state fructose beyond 3.0 THz for the first time to our knowledge. To reproduce the measured THz spectra and IR spectra of solid-state fructose, the theoretical calculations, such as MP2 and B3LYP based on isolated-molecules as well as PBE and PW91 based on unit cells, have been carried out, respectively. The calculated results showed that the PBE and PW91 calculations based on unit cells achieve better reproduction of absorption spectra of solid-state fructose than the MP2 and B3LYP calculations based on isolated-molecules, indicating the stronger influence of the intermolecular interactions for solid-state fructose compared to the intramolecular interactions for solid-state fructose, which reveals the significant effect of the surrounding environment on the vibration modes of solid-state fructose..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2700 (2018)
Investigations on Spectra of Terahertz and Raman of L-Alabinose at Fingerprint Region
SU Tong-fu, WANG Chang-qing, ZHAO Guo-zhong, FAN Su-fang, YANG Guo-yu, XU Cui-lian, and SU Hui
In order to further understand the synthesis and biodegradation mechanism of L-arabinose during the course of metabolism, terahertz time-domain spectroscopy and laser Raman spectrometer were used to measure the vibrations of their groups in this paper. The results shows that: in the frequency range of 5～85 cm-1 frequenIn order to further understand the synthesis and biodegradation mechanism of L-arabinose during the course of metabolism, terahertz time-domain spectroscopy and laser Raman spectrometer were used to measure the vibrations of their groups in this paper. The results shows that: in the frequency range of 5～85 cm-1 frequency range, The 49.5 and 72.2 cm-1 vibrational peaks were detected and the two vibrations were in agreement with the frequencies of anomalous dispersion in the curve of refraction index, the second peak was detected for the first time. Therefore, the two vibration peaks could be as characteristic absorption peaks of L-arabinose because of their strong absorption. To the most, the wave type of terahertz spectra in this range was very similar to the theoretical wave type of the simple combinations of the three isomers, and the sample was not a single component, but a mixture of three isomers. Raman spectra showed that vibrations of L-arabinose were concise and clear and that vibrations in fingerprint frequency ranges were divided into four characteristic vribrational regions(from high to low): stretching vibrations of bonds in pyran cycle, rocking of methylene, twisting of H—O in cycle and torsions and deformations of cycle skeleton, including puckering. The vibrations of α-, β- and open chain isomers were calculated by B3LYP/6-311G** according to DFT, respectively. The vibrations of the three isomer were assigned by potential energy distribution. Comparisons between observed and theoretical curves were that frequencies of theoretical curves showed red shift for vibrations of L-arabinose and the exact causes must be confirmed by further tests..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2713 (2018)
Wavelength Selective Terahertz Time-Domain Spectroscopy for Paper Thickness Measurement
CAO Bing-hua, WANG Wei, FAN Meng-bao, and WEI Zhong-liang
Wavelength selection of spectra plays an important role in the quantitative analysis of terahertz spectroscopy. In this paper, a new method for quantitative measurement of paper sheet thickness is presented based on wavelength selection of terahertz phase spectra. Besides, binary particle swarm optimization (BPSO) algoWavelength selection of spectra plays an important role in the quantitative analysis of terahertz spectroscopy. In this paper, a new method for quantitative measurement of paper sheet thickness is presented based on wavelength selection of terahertz phase spectra. Besides, binary particle swarm optimization (BPSO) algorithm is applied in wavelength selection of terahertz phase spectra and partial least square (PLS) algorithm is employed to establish the quantitative analysis model of paper sheet thickness. In addition, the root mean square error of prediction (RMSEP) is analyzed to show the performance of the method. Finally, the prediction error of the method is compared with both the methods using the raw spectra and the method using a single wavelength of the spectra. The results show that the method of this paper gives the most satisfactory quantitative accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2720 (2018)
Effects of Li Ions on the Thermal Radiation Induced by NIR Laser in Rare Earth Doped Oxide
ZHANG Yang, SUN Peng, LIU Lu, WANG De-xing, CHEN Shu-yan, CHENG Li, SU Li-ping, ZHU Zheng, and CHEN Yang
Thermal radiation induced by NIR laser, from rare earth doped oxides show promising potentials in many applications, due to their relatively high luminescent efficieny in the visible light region. Therefore, further enhancing the efficiency of this type of thermal radiation is of vital importance. In this paper, we proThermal radiation induced by NIR laser, from rare earth doped oxides show promising potentials in many applications, due to their relatively high luminescent efficieny in the visible light region. Therefore, further enhancing the efficiency of this type of thermal radiation is of vital importance. In this paper, we proposed a protocol to improve the luminescent efficiency of the thermal radiation, that is, introducing Li+ into the oxide hosts, which on one hand could decrease the symmetry around the rare earth ions, and on the other, could create the inner defects due to the mismatch of valences. Beneficial effects of doping Li+ including the enhancement of the absorption of rare earth ions at the incident wavelength (due to the enhanced crystal field), as well as the promotion of producing heat associated with lattice phonons (owing to the increased so called “luminescence quechers”). In addition, we synthesized series of Li+ and Yb3+ doped ZrO2 using sol-gel technique to experimentally validate our proposed design, influences of doping Li ions on the structure of the nnaocrystals were discussed on the basis of XRD and TEM tests; through the emission spectra, the effects of doping concentration were investigated as well. This work may provide references for fabricating oxide phosphors with efficient thermal radiation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2725 (2018)
Study on the Oxidation Roasting of High-Sulfur Bauxite by DSC-TG-FTIR Coupling
CHENG Si-meng, JIU Shao-wu, LI Hui, CHEN Yan-xin, and ZHAO Bo
Desulfurization is the prerequisite of high-sulfur bauxite comprehensive utilization. Researches of roasting characteristics of high-sulfur bauxite provide foundations for developing a new desulfurization technology. Coupling test of thermal analysis and Flourier transform infrared (FTIR) spectrum analysis was carried Desulfurization is the prerequisite of high-sulfur bauxite comprehensive utilization. Researches of roasting characteristics of high-sulfur bauxite provide foundations for developing a new desulfurization technology. Coupling test of thermal analysis and Flourier transform infrared (FTIR) spectrum analysis was carried out for high-sulfur bauxite with sulfur content of 4.32% from Guizhou. The types, process and main characteristics of reaction occurring during oxidation roasting process of high-sulfur bauxite were comprehensively analyzed and studied by TG, DTG, DSC and FTIR coupling method, and the development of new desulfurization process with suspension state was discussed. A new approach for infrared spectroscopy analysiswas developed to separate the release features of various components from the infrared spectroscopy of gaseous product mixture, and it was used to separate the desulfurization process and dehydration process of high-sulfur bauxite. Results showed that: The main reactions of high-sulfur bauxite in the roasting process were dewatering of diaspora, oxidation desulfurization of pyrite and decomposition of calcite. The gaseous products of the reaction were H2O(g), SO2 and CO2. Dewatering of diaspora was a single step reaction, which appeared in the range of 380.0~580.0 ℃. The reaction of oxidation of pyrite is two step reaction, and which appeared in the range of 388.0~574.0 ℃. The decomposition temperature range of calcite was at 700.0 to 860.0 ℃. The quantity of desulfurization of high sulfur bauxite can directly compensate the endothermic quantity of the dehydration. The suitable operation temperature for suspension state desulfurization process was 580.0~650.0 ℃. The conclusions of this paper can serve as references developing a new suspension desulfurization technology for high-sulfur bauxite..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2730 (2018)
Study on the Infrared Radiation Characteristics of the GOX/KERO Engine Plume
CAI Hong-hua, NIE Wan-sheng, SU Ling-yu, and SHI Tian-yi
A method for calculating infrared radiation characteristics of the gas oxygen/kerosene (GOX/KERO) engine plume considering soot particles was proposed, first of all, the simulation of engine internal flow field was carried out, and the plume flow field was calculated using the nozzle throat as the inlet boundary of theA method for calculating infrared radiation characteristics of the gas oxygen/kerosene (GOX/KERO) engine plume considering soot particles was proposed, first of all, the simulation of engine internal flow field was carried out, and the plume flow field was calculated using the nozzle throat as the inlet boundary of the gas and carbon particles, infrared radiation characteristics of the engine plume were calculated with the finite volume method (FVM) and the pseudo-gas theory based on the field parameters. The ignition experiment of the gas oxygen/kerosene engine was carried out, and the calculated results were compared with the experiment results. It was found that, the pressure errors between measurement and calculation of two pressure measurement points in the chamber were 1.4% and 3.4%, the temperature error between thermodynamics and calculation in chamber 2.16%, which verified the accuracy of the chamber flow field calculation model. The calculation results of the plume flow field containing the soot particles were in good agreement with that of the thermal imager, and the accuracy of method and model of plume flow field calculationwas proved. The plume infrared imaging in the 4.3 μm band of the calculation was in good agreement with that of the thermal imager, and the accuracy of method and model of plume infrared radiation calculation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2735 (2018)
Determination of Performance of Different Concentration Ethanol Diesel Oil Based on Mid Infrared Spectroscopy
LIU Yan-de, YE Ling-yu, TANG Tian-yi, OUYANG Ai-guo, SUN Xu-dong, and ZHANG Yu
The quantitative analysis of the performance indexes of ethanol diesel was carried out by means of medium infrared spectroscopy and chemometrics. There were 96 samples in 32 different concentrations of ethanol diesel oil solutions. Using S-G, MSC, smooth differential processing (1st D and 2nd D), SNV of methods preprocThe quantitative analysis of the performance indexes of ethanol diesel was carried out by means of medium infrared spectroscopy and chemometrics. There were 96 samples in 32 different concentrations of ethanol diesel oil solutions. Using S-G, MSC, smooth differential processing (1st D and 2nd D), SNV of methods preprocessed spectral data, combined with the screening method of eight kinds (UVE, CARS,SPA,RPLS,UVE-SPA,UVE-CARS,SPA-CARS,UVE-SPA-CARS)processing ethanol diesel MIR spectral data, and PLSR model were established respectively with density of ethanol diesel oil, viscosity and ethanol content. The results showed that: comparing the eight variables screening methods, we found that UVE-SPA-CARS-PLS has the best modeling effect on ethanol content. The correlation coefficient was 0.978 1 and the root mean square error of prediction was 0.825 5, respectively. Compared with the model established by the original spectrum, variable selection not only reduced the number of model inputs, but also improved the prediction effect..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2741 (2018)
The Micro Mid-Infrared Spectral Study on Quench of Natural and Synthetic Ametrine
SHAO Tian, LUO Ze-min, CHEN Tao, and Andy Hsitien Shen
Ametrine is the valuable variety in alpha quartz, and its mid-Infrared (MIR) spectra research helps to understand the differences of violet and yellow zones in amtrine. The natural and synthetic ametrine have the specific MIR absorption spectra in the violet-yellow color zones respectively. When quenched under the diffAmetrine is the valuable variety in alpha quartz, and its mid-Infrared (MIR) spectra research helps to understand the differences of violet and yellow zones in amtrine. The natural and synthetic ametrine have the specific MIR absorption spectra in the violet-yellow color zones respectively. When quenched under the different temperatures, the spectra can change regularly. We conducted quench experiments of natural and synthetic ametrine using tube furnace and collected the micro MIR spectra of natural and synthetic ametrine under different quench temperature in the violet-yellow color zones. The experiments suggested that water had not direct correlation to do with the color. In sharps peak at 3 585 and 3 614 cm-1 of violet zone and broad band near 3 400 cm-1 of yellow zone, the simultaneous changes of these peaks, which occurred in same temperature, indicating that when the samples heated, the structural water may play a dominant role in change. During the heat treatment, the peaks decreased in violet zone while increased in yellow zone, that could be explained by the migration of H+ or other positive ions through the structure channels of alpha-quartz. At the same time, the research pointed out that the MIR spectra of heated yellow quartz is largely similar to the amethyst one..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2749 (2018)
Rapid Detection of Tomato Mosaic Disease in Incubation Period by Infrared Thermal Imaging and Near Infrared Spectroscopy
ZHU Wen-jing, LI Lin, LI Mei-qing, LIU Ji-zhan, and WEI Xin-hua
The lagging diagnosis method of tomato mosaic disease results in untimely and excessive application of pesticide. The conventional nondestructive testing methods were unable to be applied at early recognition in the incubation period. In this study, the infrared thermal imaging information acquisition system was designThe lagging diagnosis method of tomato mosaic disease results in untimely and excessive application of pesticide. The conventional nondestructive testing methods were unable to be applied at early recognition in the incubation period. In this study, the infrared thermal imaging information acquisition system was designed. The efficiency and accuracy of this system were also tested. The main components of the system included a shell box, an infrared thermal image acquirer, a temperature and lift controller, a heating plate and a lift load table. The system developed in this study has the capacity to adjust the shooting temperature manually according to the requirements of the temperature range in a typical experiment. To test the precision of the system, the non-resistant tomatos variety L-402 were cultivated by Institute of Vegetables of Liaoning Academy of Agricultural Sciences in the Venlo type greenhouse of the Ministry & Provinces?Co - construction Key Laboratory of modern agricultural equipment and technology of Jiangsu University. The virus (Tobacccco mosaic virus, ToMV) infection experiment was conducted by using the method of leaf surface friction before the flowering stage. In the virus infection experiment, tomato plants were divided into three groups. The severe infection group (SI) was inoculated with the original virus solution. The Low-grade infection group (LI) was inoculated with diluted virus solution (500 times dilution by phosphate buffer). The control group (CG) was sprayed with equal amount of phosphate buffer. After 10 days of inoculation, spots began to appear on leaves of tomato plants in SI group, suggesting that the first 9 days were the incubation period of tomato mosaic disease. Infrared thermal imaging system was used to collect infrared thermal imaging of those three groups with a total sample size of 144 during the incubation period. The maximum temperature difference (MTD) of the leaf table was calculated to characterize the change of leaf temperature in continuous 9 days during the incubation period. The MTD value of the leaves in the CG group was statistical non-significant, but the MTD value of the leaves in both LI and SI groups was significantly changed after inoculation with the infection time of the virus. After six days of inoculation, the maximum difference of MTD value can reached 1.63 ℃. The difference gradually narrowed down from 7 days, indicating that the virus were spread to more and more regions on the infected leaves and raised the temperature of the whole leaf. Two spectral acquisition methods were conducted. The first one was Thermal-imaging collection method (TCM). During TCM, spectra were intensively acquired during the temperature mutation region which was calculated based on the MTD value from the infrared thermograph. The second method was to acquire spectrum on randomly selected points on the tip, middle, and base of leaves without focusing on the location of the lesion. This spectrum acquisition method was recognized as random collection method (RCM). The principle of TCM to select the effective position for the three spectral acquisition points was that the average MTD value of the mutation zone in the LI group was 0.3, 0.7 and 0.5 ℃ higher than those in the CG group on the 3rd, 6th and 9th day after inoculation respectively.The average MTD value of the mutation zone in the SI group was 0.5, 1.2 and 0.8 ℃ higher than those in the CG group on the 3rd, 6th and 9th day after inoculation, respectively. Lesion position met the above criteria could be considered as an optional area for TCM. All samples were identified by using Support Vector Machine (SVM) algorithm for discriminant analysis. The principal component analysis (PCA) was used to compress the spectral information of 2 151 wavelength points. The cumulative variance contribution rate of the first six principal components has reached 99%. The samples of 3, 6 and 9 d were divided into the correction set and the prediction set at the ratio of 2∶1, and the disease degree of the prediction set samples was identified. The total recognition rates of the models established by the two methods are 92.59% and 99.77%, respectively. In the spectral recognition model established by TCM, only one sample from LI group after 3 d was unable to be identified and mistaken into CG group. Despite this sample, the remaining recognition rate reached 100%. The results showed that it is feasible to use near infrared spectroscopy to identify tomato mosaic disease at early stage. Using infrared thermal imagingin combination with near-infrared spectroscopy technique allows us to establish higher recognition rate models for identification of tomato mosaic disease during incubation period. This study provided an alternative method for the development of follow-up control process, and created a new model to break through the bottleneck of the early precise pesticide spraying of crops. It overcame the point source of NIR sampling randomness and helped to establish a more accurate intelligent pesticide application system in greenhouse..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2757 (2018)
Near Infrared Spectroscopy Analysis Based Machine Learning to Identify Haploids in Maize
LI Wei, LI Jin-long, LI Wei-jun, LIU Li-wei, LI Hao-guang, CHEN Chen, and CHEN Shao-jiang
Haploid identification is a very important part of doubled haploid technology in maize. In this reasearch, we studied the near-infrared transmission spectra of a large number seeds of haploids and heterozygous diploids to establish an accurate model for haploid identification. Compared with the average spectrum of all Haploid identification is a very important part of doubled haploid technology in maize. In this reasearch, we studied the near-infrared transmission spectra of a large number seeds of haploids and heterozygous diploids to establish an accurate model for haploid identification. Compared with the average spectrum of all haploids and heterozygous diploids, it was found that the absorption peak position of the two spectra was almost the same, but the haploid absorbance was slightly higher than that of heterozygous diploid, especially at the wavelengths of 940～1 120 and 1 180～1 316 nm which shared larger differences. Based on the near infrared spectra of haploids and heterozygous diploids from three different sourcegermplasm, different machine learning algorithms were called to construct a haploid selection model, accuracy of models developed with different spectral preprocessing methods were compared, and the effects of datasets to model evaluation were also studied. By comparison with several models, the haploid identification accuracy of the partial least squares method and the neural network algorithm reached a high accuracy of 95.42% and 93.26% respectively. The results of the testing set were consistent with the accuracy of the model, indicating that the two algorithms are suitable for large-scale screening of haploids. By using the partial least squares model, the accuracy of the model developed from the spectral preprocessing methods of smoothing was the best. Compared with the modeling results of different data size, it was found that increasing the data set in a certain range could improve the accuracy of the model. And when proportion of haploids was high enough, the recall rate of haploid prediction would reach up to 100%. In addition, haploids and heterozygous diploids which was difficult to be identified by R1-nj color were selected to form a new dataset. The accuracy of the partial least squares method trained by this dataset was 93.39%. This showed the advantages of NIR machine learning method for haploid identification, which could be used to achieve accurate identification in the case independent of R1-nj color expression. The method of NIR haploid identification based on machine learning has high accuracy and efficiency, and the method can be optimized with increasing data. This research paved a way for the intelligent identification of haploid..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2763 (2018)
Visualization of the Interaction between NDs and Cells with 3D Raman Imaging
LI Dan-dan, CHEN Xin, WANG Hong, FU Yang, YU Yuan, and ZHI Jin-fang
Nanodiamonds, with good bio-compatibility, chemical stability, drug accommodatingability, fluorescence signals and many other superior properties, have attracted growing attention for anti-cancer drug delivery and bio-imaging applications in recent decades. In this work, the intrinsic Raman signal (1 332 cm-1) of nanodNanodiamonds, with good bio-compatibility, chemical stability, drug accommodatingability, fluorescence signals and many other superior properties, have attracted growing attention for anti-cancer drug delivery and bio-imaging applications in recent decades. In this work, the intrinsic Raman signal (1 332 cm-1) of nanodiamonds (NDs) with different sizes synthesized by high temperature high pressure (HTHP) and explosion methods were investigated and compared, in order to select suitable NDs as Raman probes for bio-application, indicating that HTHP synthesized NDs with the size of 100 nm were preferable. NDs were surface homogenized to remove the impurity for further bio-application through acid carboxylation, which was verified with Scanning Electron Microscopy (SEM), Frourier Transform Infared Spectroscopy (FTIR), Raman Spectroscopy and size analysis. And the cytotoxicity of NDs to different cell lines was confirmed with Cell Counting Kit-8 (CCK-8) assay, assuring the good bio-compatibility of NDs and their potential application in bio-system. Besides, based on the sharp Raman peak of NDs at 1 332 cm-1 and the representative Raman vibration band of cells in 2 800～3 000 cm-1 range, NDs were used as Raman bio-probes for the fast localization of NDs in HeLa cells, and the non-invasive dual-color two-dimensional (2D) confocal Raman imaging technique with 532 nm laser was successfully realized. Furthermore, the uptake process of NDs into HepG2 cells was visualized with Raman mapping, revealing the time-dependent behavior of this internalization process. Besides, the endocytosis and localization of NDs as Raman probes by different cells, including HeLa, HepG2, C6 and MDCK cells, were further investigated using the advanced three-dimensional (3D) confocal Raman imaging microscopy, which could render detailed information about the interaction of NDs and cells. And it was observed that the endocytosis of NDs was influenced by cell lines, not only for cancer and non-cancer cells, but also for different cancer cell lines, providing further potential applications for bio-imagingand cancer diagnosis. These results were encouraging and sufficient for following bio-medical studies..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2770 (2018)
Hydrogen Bonding Effect on the Surface Tension and Viscosity of DMSO Aqueous Solutions Studied by Raman Spectroscopy
OUYANG Shun-li, ZHANG Ming-zhe, HU Qing-cheng, WEI Hai-yan, and WU Nan-nan
In the present paper, surface tensions and viscosities for DMSO aqueous solutions with volume concentration range from 5 to 100% and ultrapure water weremeasured by the ZL-10 Type surface tension instrument and NDJ-5S digital readout viscometer．Dependences of Raman shiftseffects of hydrogen bands on DMSO concentrationwIn the present paper, surface tensions and viscosities for DMSO aqueous solutions with volume concentration range from 5 to 100% and ultrapure water weremeasured by the ZL-10 Type surface tension instrument and NDJ-5S digital readout viscometer．Dependences of Raman shiftseffects of hydrogen bands on DMSO concentrationwere investigated. The results indicated that, surface tension was influenced by the hydrogen band behavior with variation of concentration, which has a reciprocal correlation with the hydrogen band intensity. The hydrogen band behavior between DMSO and water influenced viscosity more intricately, with viscosity having quadratic relationshipwith concentration. The influence factors include several aspects like the hydrogen band intensity and spatial directionality. We explored aexperimental method about using Raman spectrospcopy to investigate the relationship between microstsucture and macroscopic physical properities of aqueous solution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2778 (2018)
Surface-Enhanced Raman Spectroscopy for Rapid and Accurate Detection of Fenitrothion Residue in Maize
HUANG Lin-sheng, WANG Fang, WENG Shi-zhuang, PAN Fang-fang, and LIANG Dong
Fenitrothion, an organophosphate insecticide widely appeared in agricultural crop cultivation, is commonly used to prevent and control insect pests in maize. However, excessive or unreasonable application lead to the accumulation of pesticide residues in maize, which concern to agricultural products safety and human heFenitrothion, an organophosphate insecticide widely appeared in agricultural crop cultivation, is commonly used to prevent and control insect pests in maize. However, excessive or unreasonable application lead to the accumulation of pesticide residues in maize, which concern to agricultural products safety and human health. The routine methods for fenitrothion detection are chromatography-mass spectrometry and high performance liquid chromatography, which are both highly accurate. Nevertheless, the shortcoming of above methods is that they need well-trained personnel, complicated sample preparation, considerable detection time. Surface-enhanced Raman spectroscopy (SERS) has the advantages of rapid speed, high sensitivity, excellent specificity, and extensively applied for rapid detection of trace residues in agricultural products. In this paper, an accurate methodology for detection of fenitrothion residues in maize was developed using surface enhanced Raman spectroscopy and chemometric methods. The gold nanorods solution synthesized by the two-step seed-mediated growth method was used as Raman active substrate. And SERS spectra of 600 to 1 800 cm-1 were measured. Comparing SERS spectrum of ethanol solution with fenitrothion and gold nanorods, the characteristic peaks of fenitrothion were determined at 650, 830, 1 082, 1 241, 1 344 and 1 581 cm-1. A simple pretreatment method was developed for extraction of fenitrothion residues in maize. Maize contaminated with fenitrothion was grinded, and then ethanol solution was added to extract fenitrothion residues twice. Next, the two extraction were centrifuged and the supernatant were acquired, followed by mixed, concentrated and evaporated in water bath. The concentrated supernatant was used for SERS measurement. Fifty samples were prepared for each concentration of fenitrothion residues in maize. Reference value of residue in extraction solution was detected by gas chromatography-mass spectrometer. Through observing the spectrum of maize extraction with fenitrothion residues, the characteristic peak intensity of 1 082, 1 241 and 1 581 cm-1 were rapidly weakened or even disappeared as the fenitrothion residues decreased in different concentration residues extraction whereas the peak at 650, 830 and 1 344 cm-1 remained visible with fenitrothion of 0.48 μg·mL-1. Spectra of extraction with 0.37 μg·mL-1 fenitrothion residues were basically consistent with uncontaminated samples extraction. Principal component analysis (PCA) was adopted to extract the main information of spectra of fenitrothion residues. The principal component scores for spectra of 0.37 μg·mL-1 fenitrothion residues and uncontaminated samples were overlapped in scatter plot while others were distributed in different positions. It can be further determined from the scatter plot that the detection limit of fenitrothion in maize could reach 0.48 μg·mL-1, which is lower than the maximum residue limit of China in crops, suggests SERS is of high sensitivity. The intensity variation of characteristic peak of 650, 830 and 1 344 cm-1 in 50 samples with a concentration of 14.25 μg·mL-1 fenitrothion residues were analyzed, and the collected spectra showed a good repeatability while the relative standard deviation (RSD) was only 3.12%. Support vector machine regression (SVR) was employed for quantitative analysis of fenitrothion residue. Additionally, Savitzky-Golay convolution smoothing and wavelet transform (WT)were used for the pretreatment of spectral data. The calibration and prediction set of samples were divided by Kennard-Stone algorithm. Quantitative evaluation of model performance was based on root mean square error of correction (RMSEC), coefficient of determination of correction (R2ｃ), root mean square error of prediction (RMSEP) and coefficient of determination of prediction (R2p). Optimal regression model, which has minimal prediction error, was developed by SVR and WT. The correction set of RMSEC and R2c were 0.103 2 μg·mL-1 and 0.999 74 while the prediction set of RMSEP and R2p were 0.134 1 μg·mL-1 and 0.999 60 respectively. Furthermore, the predicted value of optimal model was basically in consonance with GC-MS, and predicted recovery of fenitrothion residues in maize was 95.31%~100.66%. Results demonstrates that SERS combined with chemometric method is feasible to detect fenitrothion residues in maize. This method is expected to be generalized to detect varieties of pesticide residues in other crops, providing a novel approach for the safety detection of agricultural products..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2782 (2018)
Screening of Antibiotic-Resistant Bacteria in Activated Sludge and Study of Their Raman Spectroscopy
YU Qiang, CHEN You-peng, and GUO Jin-song
Antibiotic pharmaceutical wastewater is difficult to be treated in wastewater treatment field. The study of interaction mechanism between antibiotic and microorganism is of great significance for solving antibiotic wastewater treatment problem. As Raman spectroscopy offers a nondestructive, noninvasive, and water-insenAntibiotic pharmaceutical wastewater is difficult to be treated in wastewater treatment field. The study of interaction mechanism between antibiotic and microorganism is of great significance for solving antibiotic wastewater treatment problem. As Raman spectroscopy offers a nondestructive, noninvasive, and water-insensitive test tool, it has been more and more widely applied in the study of biology and medicine. This work isolated 4 strains of antibiotic-resistant bacteria from activated sludge taken from sewage treatment reactor by using streak plate method and spread plate method, and the drug degradation effect of these strains is assessed, which shows the highest degradation rate reached 45.44%. Besides, sequence of these strains’ 16S rRNA gene was analyzed to identify them, and the result shows that these strains belong to Aeromonas sp., Bacillus sp. and Rhodococcus sp.. Raman spectroscopies of these stains under different conditions were taken to investigate the best test condition of bacteria’s Raman spectroscopy, and the result shows that CaF2 can be the best substrate. Then the Raman spectroscopies of these strains were obtained and the difference among them is analyzed by using principal component analysis, and three principal components were extracted, of which the accumulated load reached 83.9%. Among all the variables, 748, 1 003, 1 126 cm-1 belong to the first principal component, 1 661, 1 448 cm-1 belong to the second, and 855 cm-1 belongs to the third. This research characterized biological macromolecules of stains screened from activated sludge by Raman spectroscopy and well distinguished them, proving the reliability and superiority of Raman spectroscopy for applying to mechanism study of microorganism interaction in wastewater treatment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2788 (2018)
Rapid and Simultaneous Detection of Sodium Benzoate and Potassium Sorbate in Cocktail Based on Surface-Enhanced Raman Spectroscopy
FANG Xiao-qian, PENG Yan-kun, WANG Wen-xiu, ZHENG Xiao-chun, LI Yong-yu, and BU Xiao-pu
This paper established an optimal analytical model for rapid and simultaneous detection of sodium benzoate and potassium sorbate in cocktail by using surface-enhanced Raman technique, based on the self-built laboratory Raman point scanning system. Silver colloidal nanoparticles were prepared by reduction of silver nitrThis paper established an optimal analytical model for rapid and simultaneous detection of sodium benzoate and potassium sorbate in cocktail by using surface-enhanced Raman technique, based on the self-built laboratory Raman point scanning system. Silver colloidal nanoparticles were prepared by reduction of silver nitrate with sodium citrate. In addition, the Raman spectra of sodium benzoate and potassium sorbate standard were compared with surface-enhanced Raman spectroscopy of cocktail samples containing sodium benzoate and potassium sorbate. 846.1, 1 007 and 1 605 cm-1 were surface-enhanced Raman characteristic shifts of sodium benzoate. 1 164, 1 389 and 1 651 cm-1 were surface-enhanced Raman characteristic shifts of potassium sorbate. At the same time, the stability of the peak in the Raman characteristic shift and the interrelation of Raman shift peak strength of two kinds of preservatives in the cocktail were analyzed. The detection method was of high stability, and the two kinds of preservatives were basically no interaction. Moreover, 42 sodium benzoate concentrations of 0.154 3~1.5 g·kg-1 and 45 potassium sorbate concentrations of 0.062~1.5 g·kg-1 were prepared to establish a linear regression model in cocktail. The best prediction models for sodium benzoate and potassium sorbate were two respective linear regression model established by 1 007, 1 605 and 1 164 1 651 cm-1. Besides, 43 different concentrations of sodium benzoate and potassium sorbate cocktail samples were predicted by the best prediction models. The result showed that the correlation coefficients (r) of sodium benzoate and potassium sorbate were 0.949 3, 0.921 8, root mean square error (RMSE) were respectively 0.088 2 and 0.142 9 g·kg-1, respectively. The rapid and quantitative determination of sodium benzoate and potassium sorbate in commercial cocktail can be realized by surface enhanced Raman spectroscopy. The results provides technical support for simultaneous and real-time online monitoring of preservatives in liquid food..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2794 (2018)
A Raman Spectrum Detection Method for Quality of Cucumber Covered PE Plastic Wrap
LI Yan, PENG Yan-kun, and ZHAI Chen
Now transparent plastic wrap packaging gains great popularity because of its characteristics like convenience, economy and sanitation and be widely used in supermarket stores and daily life, which increases difficulties in detecting food and agricultural products. Thus a rapid nondestructive detecting method to detect Now transparent plastic wrap packaging gains great popularity because of its characteristics like convenience, economy and sanitation and be widely used in supermarket stores and daily life, which increases difficulties in detecting food and agricultural products. Thus a rapid nondestructive detecting method to detect agricultural products covered with transparent film is urgently needed. Chlorophyll is one of the vital factors which affect cucumber quality. The research mainly makes a thorough inquiry in the influence of food plastic wrap(material and number of plies) to Raman characteristic peaks of chlorophyll in cucumber. In the research, point-to-point Raman detecting system is used to gather Raman spectrum of cucumber covered with no plastic wrap and several layers of plastic wrap. Fluorescence background of Raman spectrum of cucumber is deducted with Savitzky-Golay five-spot smoothing and adaptive iterative least square method to investigate the influence of PE plastic wrap (1 to 6 layers) to Raman characteristic peaks of chlorophyll in agricultural products like cucumber. One detecting spot is detected three times to get its average value after covering a layer of plastic wrap. And nine detecting spots is got from a cucumber sample. The Raman spectrum of cucumber covered with plastic wraps is gathered and processed. Then the prediction model between reduction value of Raman characteristic peaks of chlorophyll (in the position of 1 158 and 1 528 cm-1) and layers of plastic wrap can be built. And then predictive effect of the model can be evaluated. With the increase of layers of plastic wrap, linear relationship is clear between layers of transparent package and intensity of Raman characteristic peaks of chlorophyll in cucumber. And as a reliable validation method, unary linear regression is used to judge the degree of correlation between the reduction value and layers of transparent package. It can be extracted that the reduction value of intensity of Raman characteristic peaks of chlorophyll in 1 158 and 1 528 cm-1 respectively are 81.4 and 103.1 which occupy 7.98% and 8.56% of intensity of Raman characteristic peaks of chlorophyll in cucumber without plastic wrap. In addition, the correlation index of verification result of several groups are all more than 0.95. And the correlation index of the results when verifying the change rulealso researches 0.94. From the research we know thatin the detection of chlorophyll in cucumber, rape and celery, the reduction value of intensity of Raman characteristic peaks of chlorophyll will also occupies 7.9%～8.6% and 8.1%～8.6% of the intensity value after covering a layer of plastic wraprespectively. And with Chlorophyll concentration of samples increasing, the detection effects become obvious. It is assumed that the scattering to exciting laser by plastic wrap is the reason that makes the intensity of Raman characteristic peaks of chlorophyll decrease with a linear relationship. The Raman characteristic peaks of plastic make no effect to the detection results. And it can be speculated the intensity of Raman characteristic peaks of chlorophyll also decreases with a linear relationship in detecting agricultural products covered with PVC or PVDC wrap. Similar results also will be got when detecting chlorophyll in other agricultural products. The research provides a new method in detecting the quality of fruits and vegetables with transparent package..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2800 (2018)
The Conformation of Sophocarpidin by Vibrational Circular Dichroism and DFT Calculations
SUN Ning-jie, CAI Xiao-li, ZHANG Yue-fei, CHI Ru-an, and Yunjie Xu
Sophocarpidin was measured in thin film using a Fourier Transform infrared spectrometer (FTIR) with a vibrational circular dichroism (VCD) module, meanwhile, the theoretical IR and VCD spectroscopy were calculated at the B3LYP/cc-PVTZ and B3LYP/6-311+G(d,p) levels of theory in density functional theory (DFT) within theSophocarpidin was measured in thin film using a Fourier Transform infrared spectrometer (FTIR) with a vibrational circular dichroism (VCD) module, meanwhile, the theoretical IR and VCD spectroscopy were calculated at the B3LYP/cc-PVTZ and B3LYP/6-311+G(d,p) levels of theory in density functional theory (DFT) within the gas phase. The VCD spectroscopy can exactly obtain the conformational distribution of Sophocarpidin at room temperature and distinctly capture the information of each conformation for the sensitivity to stereoscopic structure of conformation within VCD spectra. It is essential to the drug analysis of sophocarpidin in the future. The conformational contribution at room temperature and structures were determined through the comparison of experimental and simulated spectra. The Boltzmann-weighted IR and VCD spectra based on free energy at the B3LYP/6-311+G(d,p) level of theory show good agreement with the observed experimental spectra. Two main conformations, i.e. A/B-trans C/D-trans and A/B-trans C/D-cis are identified. The ration of two conformations is 60% to 40%. The structure of A/B-ring and C/D-ring are chair-chair and chair-sofa respectively in both two dominant conformation of sophocarpidin..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2806 (2018)
Distinguishing Extra Virgin Olive Oil Based on the Correlation Coefficient of Visible Absorption Spectrum of Vegetable Oil
WANG Hong-peng, and WAN Xiong
Currently there are many brands of olive oil on the market, and the quality of olive oil is uneven, so it is an urgent need to improve the classification of olive oil classification and extra virgin olive oil identification method. Visible absorption spectroscopy can be used to detect non-added reagents without direct Currently there are many brands of olive oil on the market, and the quality of olive oil is uneven, so it is an urgent need to improve the classification of olive oil classification and extra virgin olive oil identification method. Visible absorption spectroscopy can be used to detect non-added reagents without direct contact with the sample. Therefore, for the purpose of distinguishing extra virgin olive oil, the spectroscopic measurement of different kinds of vegetable oils was carried out by visible absorption spectroscopy. In order to distinguish the extra virgin olive oils, spectroscopic measurements of different kinds of vegetable oils were carried out using visible absorption spectroscopy. It was found that the extra virgin olive oil had four distinct absorption peaks in the wavelength of 500～780 nm, while other kinds of vegetable oils had weak or no absorption in this band. what’s more, the spectral characteristics of the same brand of vegetable oil were very similar. The correlation coefficients of the visible absorption spectra of vegetable oils in four different wavelength ranges were calculated, and the correlation coefficients of the visible absorption spectra of different kinds of vegetable oils were compared. The results showed that the spectral correlation coefficients of the extra virgin olive oils in the wavelength range of 520～700 nm were 0.999 6. The spectral correlation coefficients between extra virgin olive oil and other kinds of vegetable oil were lower than 0.267 8, and the correlation coefficients between extra virgin olive oil and other olive oils were between 0.194 6 and 0.835 8. The results showed that the correlation coefficient method of visible absorption spectra is a fast and non-contact method for distinguishing extra virgin olive oil. In this paper, a method for rapid identification of extra virgin olive oil was established, that is, the correlation coefficient method of visible absorption spectrum. The method has a certain application value in the actual identification of extra virgin olive oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2814 (2018)
Study on Biological Toxicity Response Characteristics of Algae Chlorophyll Fluorescence to Herbicides
ZHAO De-hua, CUI Jian-sheng, DUAN Li-li, WU Tong, WANG Li-xin, LIU Da-xi, and GENG Qing-jun
Chlorella pyrenoidosa, Microcystis aeruginosa and Scenedesmus obliqnus were selected as sensitive algae in this experiment. The effect of microalgae Phtosynthesis characteristic was studied after exposure of 4 kinds of herbicides (Atrazine, Diuron, Propanil and Bentazone) and its mixture. Meanwhile, the best response tChlorella pyrenoidosa, Microcystis aeruginosa and Scenedesmus obliqnus were selected as sensitive algae in this experiment. The effect of microalgae Phtosynthesis characteristic was studied after exposure of 4 kinds of herbicides (Atrazine, Diuron, Propanil and Bentazone) and its mixture. Meanwhile, the best response time of microalgae fluorescence to the herbicides was determined in this study. The results showed that 4 selected herbicides significantly reduced the algal cells in the thylakoid membrane of light system Ⅱ maximum photosynthetic efficiency (Fv/Fm), the actual photosynthetic efficiency (Y(Ⅱ)), the absolute electron transport rate (ETR) and photochemical quenching coefficient (qP), however, increased non-photochemical quenching coefficient (qN) with the increasing herbicide dosages. The Chlorella pyrenoidosa at 400 μg·L-1 Diuron had the largest decrement of Fv/Fm(41%). Algae all displayed the effects of different degree on photoinhibition in conditions of 4 kinds of herbicides individual and mixing stressing, with the decrease of photosynthetic efficiency, electron transfer rate and photosynthetic activity, but increase of light protection ability. Algae itself had a certain light protection mechanism that could reduce the influence of herbicides stress. Herbicides affected the intensity of chlorophyll fluorescence, in which the effect of Bentazone on Chlorella pyrenoidosa was the most significant. The intensity of Chlorella pyrenoidosa chlorophyll fluorescence at 400 μg·L-1 Bentazone had the largest decrement (44%)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2820 (2018)
Aging Behavior of Bitumen Based on Three-Dimensional Fluorescence Spectroscopy
TANG Ning, YANG Yu-li, FANG Ting, WANG Wen-li, CAO Shi-yue, and PAN Wen-hao
Bitumen is easy to age under the natural environment of light, heat and oxygen. A good deal of damages of pavement caused by bitumen aging such as crack, chap and trenches, as well as the service life of asphalt pavement are shortened. In order to improve the durability of asphalt pavement and reveal the change rule ofBitumen is easy to age under the natural environment of light, heat and oxygen. A good deal of damages of pavement caused by bitumen aging such as crack, chap and trenches, as well as the service life of asphalt pavement are shortened. In order to improve the durability of asphalt pavement and reveal the change rule of components and structure during the bitumen aging process, the fluorescence spectroscopy technique was carried out from the phenomenon of fluorescence quenching of bitumen in this paper. There are two bitumen that were carried out by ultraviolet aging (UV) and thin-film oven test (TFOT). The properties and components of bitumen were studied before and after aging. Furthermore, fluorescence spectrogram of bitumen was obtained by fluorescence spectrophotometer, and the characteristic of spectrogram was analyzed. In addition, the coordinates of fluorescence peak were found from the spectrogram, and the shifted vector was calculated at last. The results showed that optimum concentration is 0.1 g·L-1 to avoid fluorescence quenching. After aging, softening point of bitumen increases, penetration and ductility decreases. Furthermore, its saturate is unchanged, aromatics decrease, resins and asphaltenes increase. According to the three-dimensional fluorescence spectrum, the coordinates of fluorescence peak of bitumen appear "blue shift" after aging, and the content of aromatics in the bitumen defines the shift distance of fluorescence peak. In addition, bitumen has aged badly when the norm of shift vector is higher than 36. As characteristic parameter of three-dimensional fluorescence spectra was analyzed, it is possible to evaluate the aging process of asphalt effectively, which is of great significance to improve the durability of bitumen..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2828 (2018)
Laser-Induced Plant Fluorescence Lifetime Correction Technique and Its Properties Analysis
WAN Wen-bo, and SU Jun-hong
Laser-induced chlorophyll fluorescence lifetime measurement is a novel technique for evaluating plant growth status and environmental monitoring. This method is developed on the basis of plant fluorescence spectrum analysis technique. According to the physical properties of chlorophyll fluorescence signal and informatiLaser-induced chlorophyll fluorescence lifetime measurement is a novel technique for evaluating plant growth status and environmental monitoring. This method is developed on the basis of plant fluorescence spectrum analysis technique. According to the physical properties of chlorophyll fluorescence signal and information simulation technology, a laser-induced chlorophyll fluorescence lifetime correction technique for improving the chlorophyll fluorescence lifetime measurement accuracy is presented in this paper. Laser-induced plant fluorescence lifetime measurement system was used to collect the chlorophyll fluorescence and its background signal. Then, the chlorophyll fluorescence decay function can be separated from the plant fluorescence signal in deconvolution algorithm, and fluorescence lifetime estimation can be obtained. Finally, the chlorophyll fluorescence lifetime correction technique was used to retrieve the precision values of fluorescence lifetime. The results of simulation and experiment show that real-time monitoring of high-precision chlorophyll fluorescence lifetime can be achieved in this method. Based on this, a large number of different concentrations chlorophyll solution were measured, and the relationship model of chlorophyll content and the fluorescence lifetime was built. In the future, this method can be used for remote sensing to monitor the algae biomass in the ocean, lake or river..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2835 (2018)
Method for Detecting Pesticide Content of Carbofuran by Fluorescence Spectrometry
WANG Yu-tian, WANG Jun-zhu, SHANG Feng-kai, and BIAN Xu
As a necessary means of preventing and controlling diseases and insect pests, the widespread use of pesticides has brought great threat to the people’s health, so finding some more sensitive methods of pesticide residues is of great significance. Fluorescence spectrometry has the advantages of good selectivity, high seAs a necessary means of preventing and controlling diseases and insect pests, the widespread use of pesticides has brought great threat to the people’s health, so finding some more sensitive methods of pesticide residues is of great significance. Fluorescence spectrometry has the advantages of good selectivity, high sensitivity, quick sampling and less sampling. It can be used in the analysis and detection of pesticide residues. In this paper, Carbofuran of self-made standard pesticide solution concentration as test samples, acetonitrile as solvent were measured on samples by fluorescence spectrometer, 3D datas will be obtained by MATLAB to get the 3D fluorescence spectra. The experimental results show that using acetonitrile as solvent has little effect on the experiment and the intensity of the fluorescence spectrum has a good linear relationship with the concentration of carbofuran solution. The coefficient of correlation R2=0.997 4 and it is close to 1. So it is a feasible and reliable method to detect the carbofuran pesticide with the three-dimensional fluorescence spectrometry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2843 (2018)
Extraction of Solar Spectral Information Based on Principal Component Analysis
CAI Yun-fang, JI Kai-fan, and XIANG Yong-yuan
Solar spectrum observation is one of the effective methods to study solar atmospheric phenomena. In this paper, a method of extracting and reconstructing solar spectral information based on principal component analysis (PCA) was proposed. Besides, the relation between the noise suppression degree of reconstructed data Solar spectrum observation is one of the effective methods to study solar atmospheric phenomena. In this paper, a method of extracting and reconstructing solar spectral information based on principal component analysis (PCA) was proposed. Besides, the relation between the noise suppression degree of reconstructed data and the order of principal components was analyzed. In addition, the signal-to-noise ratio of the spectral line and the accuracy of the Doppler velocity measurement were calculated under different principal component orders. The results showed that after the feature information extraction, the reconstructed data greatly preserved the original spectral data, and their signal-to-noise was markedly improved, thus the Doppler velocity measurement accuracy of spectral line was significantly improved, and also the amount of data storage and transmission of the 3D spectral data were greatly reduced. This method can satisfy the releasing requirements of current data standard and scientific goals of the 1-meter New Vacuum Solar Telescope. This method also provide a reference for the spectral data processing of the under construction Fiber Arrayed Solar Optical Telescope and future Chinese Giant Solar Telescope..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2847 (2018)
Stuay of Mineral Admixtures as Fine Aggregate on Hydration Products and Spectral Performance of Mortar
WU Fu-fei, DONG Shuang-kuai, ZHAO Zhen-hua, GONG Jing-wei, and SHI Ke-bin
Fly ash, lithium slag and steel slag as industrial waste, replace quality cement to prepare cement mortar and concrete, but its utilization is often low, so using these industrial waste in large quantities by using X-ray diffraction (XRD), thermal analyzer, Fourier infrared spectrometer and scanning electron microscopeFly ash, lithium slag and steel slag as industrial waste, replace quality cement to prepare cement mortar and concrete, but its utilization is often low, so using these industrial waste in large quantities by using X-ray diffraction (XRD), thermal analyzer, Fourier infrared spectrometer and scanning electron microscope analysis method, we studied the hydration products, spectral performance and microstructure of mortar after mineral admixtures as fine aggregate, and the change laws of mortar strength with the replacement rate (0%, 30%, 50%, 70% and 100%) were analyzed. Test results showed that the hydration products were CSH gel, Ca(OH)2, a small amount of AFt and Four kinds of slurry hydration products mainly for CSH gel, Ca(OH)2, a small amount of AFt and unhydrated particles (Al2O3 and SiO2) for cement paste, cement-lithium slag paste, cement-fly ash paste, cement-steel slag paste, which contain a certain Li2O·Al2O3·SiO2, Ca1.56SiO3.5·xH2O, and RO phase, respectively. Characteristic peak was 3 467, 3 438, 2 923, 2 348, 1 638, 1 429, 1 111, 1 000, 768, 696 and 462 cm-1 for four paste, but its strong peak was different and activity was also different, which was involved in the level of secondary hydration reaction is also different, so the content of Ca(OH)2 in cement-steel slag paste was significantly higher than cement-lithium slag paste and cement-fly ash paste. It played volcanic activity and filling effect when mineral admixtures replaced cement or fine aggregate. The flexural strength and compressive strength of mortar with 100% mineral admixture (lithium slag, fly ash and steel slag) were higher than pure cement mortar, it was about 37.77%/51.88%, 14.71%/11.70%, 14.71%/34.88%, respectively, But the flexural strength and compressive strength reached the maximum when the dosage of mineral admixtures was different. Therefore, mineral admixtures as fine aggregate of mortar were feasible, which can greatly improve the use of industrial waste in the concrete industry, and can achieve the result of energy conservation and emissions reduction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2853 (2018)
A Wide-Range Multi-Spectral Pyrometer for True Temperature Measurement of Solid Rocket Engine Plume
WANG Chang-hui, LIANG Mei, LIANG Lei, and SUN Xiao-gang
The lower limit of the existing multi-spectral pyrometer is higher than 1 173 K (900 ℃), which is not suitable for the measurement of the true temperature range of a new rocket plume (900~2 700 K). A wide-range multi-spectral pyrometer for true temperature measurement of the solid rocket engine plume is developed to soThe lower limit of the existing multi-spectral pyrometer is higher than 1 173 K (900 ℃), which is not suitable for the measurement of the true temperature range of a new rocket plume (900~2 700 K). A wide-range multi-spectral pyrometer for true temperature measurement of the solid rocket engine plume is developed to solve the problem that existing multi-spectral pyrometers cannot measure the plume true temperature when the temperature is lower than 1 173 K. The pyrometer uses a parallel connection method of the photoelectric detectors adjacent pixels, and proposes a temperature calibration method for 900~1 173 K region on the basis of the logarithmic function, so as to broaden the range of the measuring temperature pyrometer. The field measurement is carried out on the three targets of a solid rocket engine plume and the experimental results verify the validity of the pyrometer..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2860 (2018)
Simulated Lunar Soil Emissivity Spectrum Measurement Experiment and Accuracy Valuation
MA Ming, CHEN Sheng-bo, LU Peng, XIAO Yang, and YANG Qian
The minerals identification and component retrieval obtained from reflectance spectrum of lunar samples were greatly affected by the environment of lunar surface, and had been applied to approximately 5% of the lunar surface where lunar soil was immature. In contrast, the emission spectrum of lunar samples which is maiThe minerals identification and component retrieval obtained from reflectance spectrum of lunar samples were greatly affected by the environment of lunar surface, and had been applied to approximately 5% of the lunar surface where lunar soil was immature. In contrast, the emission spectrum of lunar samples which is mainly composed of silicate minerals not only had obvious spectral characteristics, but also had little influence by the lunar’s atmosphere, temperature difference and vacuum. Thus a new approach to study the component and physical properties of lunar surface was offered. In the future, the emission spectrum of lunar samples collected by Chang’e 5 detector can be used to extract the compositional analysis of silicate minerals which are the main components of lunar crust. And it is important supplement to visible-near infrared spectrum in remote sensing study. However, the greatest challenge in the laboratory emissivity measurement is finding out the best measuring methods and instruments in order to obtain accurate and reliable spectrum data. In this study, using TurboFT 102F and Bruker VERTEX 70V, based on fourier infrared spectroscopy method, independent blackbody method and reflectivity method, the emission spectrums of simulated lunar soil were measured under natural laboratory, the nitrogen cold background and vacuum environment. The numerical accuracy of emissivity spectrums was analyzed and evaluated using the error propagation law or the thermal infrared emissivity spectra of Apollo samples. The study found that the reflectivity emission spectral characteristics were the most obvious and reflectivity emissivity spectral values in which measurement accuracy was the highest in the three emission spectrum measurement methods. Thus reflectivity method under sealed laboratory environment is the best choice for lunar sample emission spectrum measurement now before the simulate lunar vacuum environment is built. We hope that research and analysis results of the paper can provide a theoretical basis and technical reference for emissivity spectrum measurement of Chang’e 5 sample..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2866 (2018)
Mineralogical and Spectral Characteristics of Tanzanite
LAI Meng, LIAO Zong-ting, YANG Ru-zeng, ZHOU Zheng-yu, and ZHONG Qian
In this paper, the Tanzanite samples from Merelani Tanzania have been respectively tested and analyzed by electron probe, EMXPLUS ESR spectrometer; SDT, UV VIS spectrometer and Fu Liye transform infrared spectrometer. The results show that: the Tanzanite samples are mainly composed of SiO2, Al2O3 and CaO, V2O5 has the In this paper, the Tanzanite samples from Merelani Tanzania have been respectively tested and analyzed by electron probe, EMXPLUS ESR spectrometer; SDT, UV VIS spectrometer and Fu Liye transform infrared spectrometer. The results show that: the Tanzanite samples are mainly composed of SiO2, Al2O3 and CaO, V2O5 has the content of 0.36%, which is the most trace components; TG-DTA curves show that there is no absorption water and crystal water in Tanzanite samples, when being heated to 780 ℃, the structural water is lost, the water in the samples is about 2% of the total mass; ESR results shows obvious Fe3+ and Mn2+ electron paramagnetic signal; UV Vis spectra shows that an narrow- band absorption appears at 385 nm while a wide- band absorption appears respectively at 575 and 750 nm; infrared spectra shows that there is no absorption in 6 500~9 000 cm-1 of the Tanzanite samples. The 5 956 cm-1 is a wide absorption peak, and there is a sharp absorption peak respectively at 5 413, 5 184, 4 336, and 4 046 cm-1, which are mainly caused by the O—H, the Si—O within in the minerals as well as H2O and CO2 inside the air environment. Based on the results of EPMA and ESR analysis, the color of blue-violet Tanzanite may be mainly caused by V3+ and V5+, d—d electron transition of the crystal field of Fe3+ and charge transfer of Fe2+ to Ti4+ to assist coloration..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2872 (2018)
Spectral Characteristics of Pb Plasma in Soil at Low Pressure
XU Song-ning, LI Chuan-xiang, NING Ri-bo, LI Qian, and JIANG Ran
In this paper, the effect of ambient pressure (between 1.01×105 and 1×102 Pa) on soil plasma radiation and element detection limit was studied by using Nd∶YAG laser to induce soil plasma. The research shows that the spectral intensity of soil plasma and the signal-to-background ratio increase first and then dIn this paper, the effect of ambient pressure (between 1.01×105 and 1×102 Pa) on soil plasma radiation and element detection limit was studied by using Nd∶YAG laser to induce soil plasma. The research shows that the spectral intensity of soil plasma and the signal-to-background ratio increase first and then decrease with decreasing pressure, and the both maximum value are 1.69 times higher at 8×104 Pa compared with normal pressure; In addition, the electron density also increases first, then decreases, and reaches a maximum of 3.56×1016 cm-3 at 8×104 Pa. Induced plasma emission spectrum has good stability and high precision at 8×104 Pa compared with normal pressure. The relative standard deviation of the signal intensity of soil plasma analysis line is 1.1%, which is significantly lower than 3.5% at normal pressure, and the stability of plasma emission spectrum is significantly improved at low pressure. Besides, the internal standard method was used to determine Pb content in soil, and the limit of detection of Pb in soil is 57.27 mg·kg-1 at 8×104 Pa, which is 39.23 mg·kg-1 lower than the limit of detection at normal pressure. The results of the study shows that spectral detection sensitivity of laser-induced breakdown spectroscopy can be improved effectively in the appropriate low pressure environment. The appropriate low pressure environment can improve the detection limit of elemental analysis and increase the accuracy and precision of spectral quantitative analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2877 (2018)
The Spectral Characteristic Variation Analysis of Three Typical Desert Plants in Growing Season
JIA Li-ge, ZHANG Bo, and WEI Huai-dong
The growth, change and succession of desert plants are significant indicators of the ecosystem in desert areas. At present, there are many studies on desert plant monitoring and desert plant spectrum based on fixed time sampling data, but few studies on a long time dynamic spectrum. The spectral discrimination of deserThe growth, change and succession of desert plants are significant indicators of the ecosystem in desert areas. At present, there are many studies on desert plant monitoring and desert plant spectrum based on fixed time sampling data, but few studies on a long time dynamic spectrum. The spectral discrimination of desert plants is due to the fact that it is affected by the time scale. In this paper, we selected plants which were representative of the desert shrubs—Tamarix ramosissima, Nitraria, Haloxylon ammodendron as samples, aiming at finding out the variation law and interspecific dynamic differentiation characteristics of the three desert plants, which was the basis for the identification of desert vegetation by spatial remote sensing. The spectral data of the vigorous plants were collected during the growing season (5~10 months) in the experiment, and the spectral curves of plants in deferent months were compared and analyzed. Results showed changes of the spectral characteristics and a corresponding phenology of desert plants in growing season. The conclusions are as follows. (1) The reflectivity curves of desert plants are consistent with the green vegetation spectrum. There are obvious peaks and valleys distribution. The slopes and areas of red-edge from large to small were as follows: Haloxylon ammodendron, Tamarix ramosissima, Nitraria. The amplitude of their spectral curve is relatively small, with rapid change. The active period of Red edge parameters is August for Tamarix, October for Nitraria, September for Haloxylon. (2) The spectral changes of desert plants are connected with the plant phenology and climate change. The spectral characteristics are related to the vegetative period, flowering period and deciduous period in the visible band, which are related to fruit period, dormancy period and rainfall in the near infrared band, and related to nutrition period, deciduous period, rainfall situation in the shortwave-infrared band. (3) In July, the spectral curves of three plants’ growth status showed that the spectral reflectance of decaying plant are higher than vigorous one in the visible band and mid-infrared band, while they are lower in the near-infrared band, which is close to the curve of soil reflectance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2881 (2018)
Dendrolimus Punctatus Walker Damage Detection Based on Fisher Discriminant Analysis and Random Forest
XU Zhang-hua, HUANG Xu-ying, LIN Lu, WANG Qian-feng, LIU Jian, CHEN Chong-cheng, YU Kun-yong, ZHOU Hua-kang, and ZHANG Hua-feng
The construction of the pest detection algorithm is a process of coupling the “ground-space” features, which is an important guarantee to realize its remote sensing monitoring. Taking Sanming City, Jiangle County, Sha County and Yanping District in Nanping City in Fujian Province as the experimental areas, it gathered The construction of the pest detection algorithm is a process of coupling the “ground-space” features, which is an important guarantee to realize its remote sensing monitoring. Taking Sanming City, Jiangle County, Sha County and Yanping District in Nanping City in Fujian Province as the experimental areas, it gathered 182 samples of Dendrolimus punctatus Walker damage and randomly divided them into training set and validation set, and 5 repeated tests and 1 test of index screening were performed. According the host representations damaged by Dendrolimus punctatus Walker, 7 ground and remote sensing characteristic indices including pine forest leaf area index (LAI), standard deviation of LAI (SEL), normalized difference vegetation index (NDVI), wetness from tasseled cap transformation (WET), green band (B2), red band (B3), near infrared band (B4) were obtained, then the models of Fisher discriminant analysis and random forest for pest levels were constructed. The detection precision, Kappa coefficient and ROC curve were used to comprehensively compare the detection effects of these two algorithms, as well as the paired t-test. The results showed that all the 7 indices have the pest responsiveness, while SEL and NDVI are relatively weak; the average detection precision of Fisher discriminant analysis in 6 tests was 73.26%, Kappa coefficient was 0.631 9, and 79.30%, 0.715 1 of RF respectively, indicating RF is significantly better than the former one (p<0.05); for the 3 pest levels of non-damage, mild damage and moderate damage, the detection precision, Kappa coefficient and AUC of RF were all significantly higher than Fisher discriminant analysis (p<0.05), while for the severe damage, Fisher was better. On the whole, the Dendrolimus punctatus Walker damage detection effect of RF is better than Fisher discriminant analysis, but Fisher has more accurate for the severe damage and the mode is clear, easy to by promoted, so these two algorithms could be comprehensively utilized to put forward the pest monitoring work. The results can provide a technical reference for the effective detection of Dendrolimus punctatus Walker damage as well as other forest pests and diseases, and lay a foundation of the remote sensing monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2888 (2018)
Prediction Method of Wood Bending Strength Based on KF Optimizing NIR
YU Hui-ling, PAN Shen, LIANG Yu-liang, and ZHANG Yi-zhuo
The bending strength is an important index to evaluate the mechanical properties of wood, and the rapid and accurate prediction of its nature is a scientific problem with engineering application value. In this paper, the wood bending strength is predicted by near infrared spectroscopy (NIR), combined with Kalman filterThe bending strength is an important index to evaluate the mechanical properties of wood, and the rapid and accurate prediction of its nature is a scientific problem with engineering application value. In this paper, the wood bending strength is predicted by near infrared spectroscopy (NIR), combined with Kalman filter (KF) and partial least squares method (PLS). A total of 126 samples of Mongolian oak (Quercus mongolica) were used, and their bending strengths were measured according to the national standard “Wood physical and mechanical properties test method”. In addition, NIR spectra were collected in the wavelengths ranging from 900 to 1 700 nm, and a pretreatment for NIR was carried out by the first order derivative combined with S-G convolution. Then, the spectrum and bending strength samples were considered as a dynamical system, the redundancy spectrum wavelength points were considered as noise signals. Besides, coefficient matrix and standard deviation were acquired by means of KF iteration, and feature selection was achieved by the ratio of coefficient to standard deviation. Finally, the prediction model of wood bending strength was build based on PLS and the selected wavelength points. The result shows that the number of variables is reduced from 117 to 18 after the KF selection, and the correlation coefficient R of the prediction model is 0.81, the root mean square error of prediction (RMSEP) is 6.59. In order to validate the effectiveness of KF, UVE and SPA were used to make a comparison, the correlation coefficient r is improved by 0.05 and 0.16 and the RMSEP is reduced by 2.33 and 7.66 respectively, which can show that KF can be used to select effective spectrum points, reduce the model dimension, and improve the applicability and accuracy of the model..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2897 (2018)
Structure Characteristics of Mineral-Microbial Residues Formed by Microbial Utilization of Lignin Based on the Participations of Different Clay Mineral Types
WANG Shuai, XU Jun-ping, CHEN Dian-yuan, JIANG Shuai, LI Xing-ji, SHENG Bing-han, and Schaeffer Sean
The catalytic action of clay minerals have an important contribution to the formation of humic substance (HS) from the lignin. In order to elucidate the relationship among the microorganisms, lignin and clay mineral effectively and reveal the structural characteristics of mineral-microbial residues, the method of liquiThe catalytic action of clay minerals have an important contribution to the formation of humic substance (HS) from the lignin. In order to elucidate the relationship among the microorganisms, lignin and clay mineral effectively and reveal the structural characteristics of mineral-microbial residues, the method of liquid shake flask culture was adopted in this article, the lignin serving as the sole C source, through the addition of kaolinite or montmorillonite to start the liquid culture of 110 days after inoculating the multiple strains, and then the mineral-microbial residues were dynamically collected and their characteristics were studied by FT-IR and SEM techniques. The results were as follows: The kaolinite particles were mostly formed from the crimp of tube-like material edges. After its participation in the formation of microbial utilization of lignin, much more structures from the fine particles of mineral-microbial residues were further aggregated and they were more integrated, in the process the structures like short tubular were increased, but the overall state still maintained the structural characteristics of hydro-kaolinite. Under the initial culture with a rich variety of nutritive elements, the kaolinite could promote the microbial reproduction, which could make a large number of microorganisms gathered on the kaolinite surface and the Si—O and Si—O—Al bonds were masked. During the process, the proportion of aliphatic C structure of mineral-microbial residues were increased; The H bonds could be formed from the conjunction of multiple O-containing functional groups of high-molecular polysaccharides and the hydration shell of kaolinite at the multiple sites. The formation of H bonds had significant effect to stabilize the lignin and its degradation products from the kaolinite. With the culture, the proportion of aromatic C structure and the polysaccharides content were gradually increased, and then the microbial residues masked on the surface of kaolinite were utilized again by the multiple strains with active ability, which could make its Si—O—Al bond reappeared; Montmorillonite was mostly composed of round particles, and the dissolution was caused by the microbial inoculation on its surface, which could make the granular structures broken and produce much more fragmented structures. Compared with 10 days, the polysaccharides of mineral-microbial residues obtained from the culture of 30 days were increased, which could make the absorption peak at 1 034~1 038 cm-1 assigned as the Si—O—Si and Si—O bonds overlayed and strengthened, and then the intensity of absorption peak at 1 034~1 038 cm-1 was weakened due to the association of polysaccharides with hydroxyl of montmorillonite surface, and simultaneously the intermolecular H bonding occurred, which was the main mechanism for the interaction of montmorillonite, microorganisms and lignin and their formation of mineral-microbial residues. The ability to stabilize organic C from the kaolinite was more than montmorillonite, which was easier to promote the formation of HS precursor substances..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2903 (2018)
Effects of Different Microwave Conditions on the Inhomogeneity of Glycation Products of Egg White and Glucose
XIE Huan, TU Zong-cai, WANG Hui, and WANG A-mei
In this study, the mixed system of the powder of egg white and glucose were constructed as the research object of glycosylation reaction model. We changed the power and heat time of the microwave oven to investigate how the position influence the level of the reaction using fluorescence, UV and other methods. In this eIn this study, the mixed system of the powder of egg white and glucose were constructed as the research object of glycosylation reaction model. We changed the power and heat time of the microwave oven to investigate how the position influence the level of the reaction using fluorescence, UV and other methods. In this experiment, egg white protein powder and glucose were quality mixed. By hand shake and full grinding, We full the plate with the mixed powder. We divided the plate into left middle and right and put the plate in the middle of the microwave oven. SDS-PAGE showed that the edge of the sample had reacted at at 240 W for 30 min, and the middle of the sample was almost unresponsive. The determination of free amino groups showed that the microwave had obvious glycosylation reaction under high power and long time .The reaction of the edge part of the sample is always more intense than the middle part of the sample. Through the fluorescence spectrum can be said that egg white protein and glucose reaction, and the edge of the sample part of the fluorescence intensity decreased more than the middle part of the sample Indicating that the edge of the sample was more intense, and the liquid phase results also confirmed the point. The sample edge of the HMF content was significantly higher than the middle part of the sample, and with time and power gradually increased; UV analysis showed that in the glycosylation reaction model plane, the edge enjoyed the highest degree of reaction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2910 (2018)
Visualization of Petroleum Hydrocarbon Content in Latosol Based on Hyperspectral Imaging Technology
CHEN Zhi-li, LIU Qiang, YIN Wen-qi, LIU Hong-tao, and YANG Yi
Hyperspectral imaging technology is a rapid and nondestructive technique, which has the characteristic of combining the image and spectra, each band will represent an image, each pixel displays a spectra. Hyperpectral image can not only obtain spectral information of the samples, but also spatial information of objectsHyperspectral imaging technology is a rapid and nondestructive technique, which has the characteristic of combining the image and spectra, each band will represent an image, each pixel displays a spectra. Hyperpectral image can not only obtain spectral information of the samples, but also spatial information of objects representation, having great value in many field at present. In this paper, hyperspectral imaging technology is used to visualize the distribution of petroleum hydrocarbons in soil. A sample of latosol samples with different petroleum hydrocarbons content was prepared and divided into modeling samples and prediction samples. Hyperspectral images were collected. In order to avoid the interference of image background, the mask was used to eliminate the background. After extracting the average spectral region of interest modeling in the sample, the successive projection algorithm select characteristics variables. Based on the extracted feature variables, on one hand, a MLR prediction modelis established, On the other hand, the characteristics of hyperspectral image are extracted from the prediction sample. Finally, the data of the pixel on the characteristic image is substituted into the model to obtain the content distribution of the petroleum hydrocarbon. Through the method of image processing, the different contents are given different colors to realize the visualization of the distribution of petroleum hydrocarbon content in latosol. The research results show that using hyperspectral imaging technique and image processing method can realize the visualization of the distribution of petroleum hydrocarbon content in latosol, providing the basis for petroleum hydrocarbon content identification and inversion of soil in large scale..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2916 (2018)
Research on the Application of UAV Multispectral Remote Sensing in the Maize Chlorophyll Prediction
MAO Zhi-hui, DENG Lei, SUN Jie, ZHANG Ai-wu, CHEN Xiang-yang, and ZHAO Yun
Chlorophyll content is an important parameter in plant growth and is closely related to crop yield. Unmanned aerial vehicle (UVA) remote sensing technology as a new means of data acquisition, has been widely used in agriculture. In this study, take maize as an example, two light and small multispectral sensors (MCA andChlorophyll content is an important parameter in plant growth and is closely related to crop yield. Unmanned aerial vehicle (UVA) remote sensing technology as a new means of data acquisition, has been widely used in agriculture. In this study, take maize as an example, two light and small multispectral sensors (MCA and Sequoia) with different spectral response functions were simultaneously mounted on a six-rotor UAV. Multispectral sensors were used to collect multispectral imagery of maize during the flowering stages under different levels of nitrogen fertilizers. At the plot level, the 26 vegetation indices based on two kinds of multi-spectral sensors were calculated and regressed with the chlorophyll content (called Soil and Plant Analyzer Development (SPAD) values) measured on the ground. The sensitivity of different band reflectivity to SPAD value were analyzed. And the accuracy and stability of SPAD values predicted by vegetation indicesbased on two multi-spectral sensors were also analyzed. The results showed that for the broadband Sequoia, the reflectance of 550 nm (green band) and 735 nm (red-edge band) is more sensitive to the change of the SPAD values, and the correlation coefficient of 550 nm and SPAD values is the largest (R2=0.802 9). For the narrowband MCA, the reflectance of 720 nm (red-edge band) has high correlation with SPAD value (R2=0.724 8), followed by the 550 nm. In addition, the correlation coefficient between the reflectance of 660 nm (Sequoia) and the SPAD value is 0.778 6, and the correlation coefficient between the reflectance of 680 (MCA) and the SPAD value is 0.488 6, which may because of the difference of central wavelength and the wavelength width. Using multi-spectral remote sensing technology of UAV to predict the SPAD values of field maize had a high accuracy, but the same vegetation index showed a great difference for different multi-spectral sensors. Among them, there were significant difference in RVI, DNVI, PVI and MSR. The broadband Sequoia is superior to the narrowband MCA. In addition, for sequoia camera, the GNDVI and RENDVI predicted the SPAD value with high accuracy, RMSE is 3.699 and 3.691, respectively. For MCA camera, RENDVI had the highest prediction accuracy (RMSE=3.742), followed by the GNDVI (RMSE=3.912). The MCARI/OSAVI with lower accuracy, the RMSE is 7.389 (Sequoia) and 7.361 (MCA). In all of the vegetation indices, the vegetation indices that using green, NIR bands and the vegetation indices constructed with red and near infrared bands were used to predict the SPAD values more accurate, which were higher than the vegetation index constructed in the red and near infrared bands. The use of complex vegetation indices constructed with more bands (three or more) did not significantly improve the prediction accuracy. For the prediction model, MCARI1 was more suitable for logarithm Model, which can effectively improve the prediction accuracy. The study also found that prediction the SPAD values in the plot level, Sequoia cameras have strong anti-jamming capability for environmental factors such as vegetation coverage, shadows and exposed soil, except for NDVI and TVI. For MCA cameras, TVI, DVI, MSAVI2, RDVI and MSAVI were very sensitive to environmental background and with a low accuracy of SPAD prediction. In addition, removal of environmental background did not always improve predictive accuracy of SPAD. This study is instructive for the prediction of high-accuracy chlorophyll content using UAV multispectral remote sensing technology, and has certain reference value for the popularization and application of precision agriculture..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2923 (2018)
A New Model for Predicting Black Soil Nutrient Content by Spectral Parameters
ZHANG Dong-hui, ZHAO Ying-jun, and QIN Kai
In the field of soil digital mapping, precision agriculture and soil resource investigation, the study of aerial hyperspectral data to provide scientific prediction results by aerial hyperspectral have become the focus of research, especially in the case of black soil rich in nutrients in Northeast China. The data sourIn the field of soil digital mapping, precision agriculture and soil resource investigation, the study of aerial hyperspectral data to provide scientific prediction results by aerial hyperspectral have become the focus of research, especially in the case of black soil rich in nutrients in Northeast China. The data source is CASI-1500 aerial hyperspectral imaging system with a spectral range of 380~1 050 nm, and spatial resolution of 1.5 m. 59 soil samples were collected from the Jiansanjiang area in Heilongjiang, and the contents of organic matter, total nitrogen, total phosphorus and total potassium were obtained. In addition, the eps-regression support vector machine model, BP neural network and PLS1 least square regression model are selected to establish the machine learning model of spectrum and content. A support vector machine (SVM) method is used to extract the total nitrogen, total phosphorus and total potassium in aerial hyperspectral data by evaluating the prediction accuracy of the 3 models. The information of organic matter is retrieved by neural network. The results revealed that the date computed by the spectral statistic, spectral characteristics and spectral values is a kind of effective spectrum of training data, which can reflect the soil comprehensive reflectance situation. The neural network method is the most accurate method for the extraction of organic matter and total potassium. The errors are 1.21% and 0.81% respectively. The accuracy is the highest in the extraction of total nitrogen and total phosphorus information by support vector machines (SVM). The comprehensive accuracy of aerial hyperspectral extraction of soil nutrients was evaluated. The extraction errors of organic matter, total nitrogen, total phosphorus and total potassium were 5.25%, 6.05%, 2.74% and 8.90%, respectively, and the total phosphorus retrieval accuracy was the highest..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2932 (2018)
Multi-Element Analysis of Jatropha curcas L. Oil Using Inductively Coupled Plasma Tandem Mass Spectrometry
JIANG Bo, and HUANG Jian-hua
According to the development of industrialization and modernization, much more conventional fossil energy resource is excess consumed, with the depletion of non-renewable energy resource, the development of new renewable energy was urgently needed. As one of the hottest concerned biodiesel resources, Jatropha curcas L.According to the development of industrialization and modernization, much more conventional fossil energy resource is excess consumed, with the depletion of non-renewable energy resource, the development of new renewable energy was urgently needed. As one of the hottest concerned biodiesel resources, Jatropha curcas L. oil was thought as the most possible renewable energy to replace conventional fossil energy resource. The trace elements in Jatropha oil might affect the performance of engine, and deteriorate environment. In order to obtain the contents of multi-elements in Jatropha curcas L. oil, an analytical method was established for accurately determination of Si, P, S, Cr and As in Jatropha curcas L. oil by using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). Jatropha oil was processed by using microwave-assisted acid-digested reaction with nitric acid and hydrogen peroxide. The changes of detection limit (DL) and background equivalent concentration (BEC) for multi-elements in different analysis modes were optimized in detail. In the MS/MS mode, O2 was introduced into the collision reaction cell (CRC), then Si+, P+, S+, Cr+ and As+ were reacted with O2 to generate SiO+2, PO+, SO+, CrO+ and AsO+ respectively; thus mass spectrometry interference can be eliminated by mass shift caused by reactions. As Cl+ can reaction with H2 to form ClH+2, while Na+, Si+, K+ elements cannot reaction with it, the mass shift caused by reaction with H2 was selected to eliminate mass spectrum interference. Sc was selected as internal standard element to correct the matrix effects. The flow rates in the CRC of different reaction gas were optimized by considering the background equivalent concentration (BEC) of analytes, and the best gas flow rate for O2 and H2 were 0.45 mL·min-1, and 7.5 mL·min-1, respectively. The DL for Na, Si, P, S, Cl, K, Ti, V, and As were 6.41, 37.3, 24.6, 118, 530, 7.96, 7.61, 0.34, and 3.20 ng·L-1, respectively, under the optimized conditions. The linear correlation coefficient (R2) of analytes were ≥0.999 8 in the range 0～50 μg·L-1. The recovery of all elements ranged from 91.2% to 108%, and the relative standard deviation (RSD) was ranged from 1.9% to 4.6%. These results showed that the proposed method was accuracy and precise. Analytical results obtained from different original Jatropha curcas L. oil showed that the contents of element P, S, and (Na+K) were ≤164, 2 310, and 1 690 ng·g-1, respectively. These indexes were much lower than those of the contents in the conventional fossil energy resource, and reached the standards of Chinese national standard of biodiesel, European IV biodiesel standard, German biodiesel standard, and American biodiesel standard. This study proposed a new approach for the determination of multi-element in Jatropha curcas L. oil with convenience and feasibility, and provided a scientific basis for the quality control and safety application of Jatropha curcas L. oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2937 (2018)
Ions-Leaching Rates Rules of Low-Calcium Fly Ash in NaOH Solutions Based on ICP-OES
YIN Bo, KANG Tian-he, KANG Jian-ting, and CHEN Yue-juan
The slow release of potential pozzolanic activity of low-calcium fly ash slows down its large-scale utilization, and enhance leaching rate of Si4+, Al3+ and Ca2+ of fly ash through alkali activation, which will play positive effects for accelerating the active release of low-calcium fly ash. In this study, low-calcium The slow release of potential pozzolanic activity of low-calcium fly ash slows down its large-scale utilization, and enhance leaching rate of Si4+, Al3+ and Ca2+ of fly ash through alkali activation, which will play positive effects for accelerating the active release of low-calcium fly ash. In this study, low-calcium fly ash was soaked and activated in five NaOH solutions of different concentrations for different time periods. The leaching rules of Si4+, Al3+ and Ca2+, changes in chemical groups, hydration product formation and evolution of microscopic morphology were tested and analyzed via Inductively coupled plasma atomic emission spectrometry, Fourier transform infrared spectroscopy, X-ray diffraction and Scanning electron microscopy. The results showed that the alkali activation effect can significantly increase the leaching rate of Si4+, Al3+ and Ca2+ ions from low-calcium fly ash, and the order of three ions leaching rates is Si4+＞Al3+＞Ca2+. The leaching rate of Si4+ and Al3+ increased with NaOH concentration, and increased logarithmically with leaching time. Ca2+ generate Ca(OH)2 precipitated in NaOH solution, which explained why the leaching rate of Ca2+ was high in water and low in NaOH solution. Fourier transform infrared spectroscopy can clearly characterize the change of chemical groups in the fingerprint zone (below 1 300 cm-1 of wavenumbers) of fly ash by alkali activation, and the changes were more obvious as the increase of the alkaline concentration and time in the activating fly ash process. Results of hydration products and micromorphology showed that the surface of fly ash particles were depolymerized under alkaline attack, and unstable ionic monomers were formed. The active Al3+ and Si4+ ions react under catalysis by OH－ to form silicate and aluminate species. They would form the aluminosilicate oligomers sol by nucleophilic substitution reaction. Thereafter, the aluminosilicate oligomers and the alkali metal cation were further polycondensed via the action of a coordination bond or an electrostatic bond to form aluminosilicate gel, which accumulated gradually. The results of the study demonstrates that using inductively coupled plasma atomic emission spectrometry to test the ions leaching rate can be used as a fast and accurate method to evaluate the pozzolanic activity of fly ash..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2943 (2018)
Quantitative Analysis of Carbon in Low-Carbon Alloy Steel by Collinear DP-LIBS
LI Lei, NIU Hong-fei, LIN Jing-jun, CHE Chang-jin, and LIN Xiao-mei
Carbon (C) is one of the key elements for alloy steel properties. In this paper, we used collinear double pulse laser induced breakdown spectroscopy to detect C in alloy steel samples under argon atmosphere in order to improve the sensitivity of detection of C content in low-carbon alloy steels. Firstly, the plasma imaCarbon (C) is one of the key elements for alloy steel properties. In this paper, we used collinear double pulse laser induced breakdown spectroscopy to detect C in alloy steel samples under argon atmosphere in order to improve the sensitivity of detection of C content in low-carbon alloy steels. Firstly, the plasma images produced by Double pulse Laser Induced Breakdown Spectroscopy (DP-LIBS) were collected by high-speed camera to study the evolution of plasma morphology with inter-pulse delay time, then combining the spectral information obtained under double pulse to establish the optimal inter-pulse delay time which was 1900 ns for carbon. In addition, the influence of argon purge and argon chamber condition on the C spectral signal intensity was studied. Between these two situations, the argon chamber can effectively shield the effect from carbon dioxide in the air, and consequently improve the analysis accuracy of C content in alloy steel. Finally, we used the internal standard method to quantify the concentration of C in alloy steel samples. Compared with the results obtained by single pulse, the R2 of calibration curve for C element increased from 0.983 to 0.991 by double pulse, and the limit of detection (LOD) decreased from 206 to 110 μg·g-1. The collinear DP-LIBS improved the limit of detection of C content in alloy steel by 1.87 times. The results show that the appropriate inter-pulse delay time can effectively improve the collinear DP-LIBS spectral quality and instrument’s sensitivity. At the same time, the secondary excitation effect of double pulse can further effectively reduce influence of the fluctuation of experimental condition, and make the calibration model possesses better linear correlation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2951 (2018)
Rapid Determination of Four Kinds of Incense by Laser-Induced Breakdown Spectroscopy
YIN Wen-yi, LIU Yu-zhu, QIU Xue-jun, ZHOU Feng-bin, and ZHANG Qi-hang
Laser-induced breakdown spectroscopy has been widely applied in many fields as a promising technique for analysis and measure. Four kinds of incense (wormwood incense, Tibetan incense, sanders, agilawood) sample have been measured and analyzed by the method of libs and then we get the elements composition of the sampleLaser-induced breakdown spectroscopy has been widely applied in many fields as a promising technique for analysis and measure. Four kinds of incense (wormwood incense, Tibetan incense, sanders, agilawood) sample have been measured and analyzed by the method of libs and then we get the elements composition of the samples. The relative concentrations of Cu, Mn, Ca, Fe in these four kinds of incense are estimated by the method of statistical analysis. Based on local thermodynamic equilibrium assumption, the plasma temperature of Ca element is obtained. The experimental results will provide a basis for the feasibility of rapid detection and quantitative elemental analysis of incense with the laser-induced breakdown spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2957 (2018)
Extracting Convolutional Features of WDMS Spectra with Anti Bayesian Learning Paradigm
WANG Wen-yu, GUO Ge-lin, MA Chun-yu, and JIANG Bin
In the task of White Dwarf+Main Sequence (WDMS) finding in massive spectral data release, convolution can significantly improve the classification accuracy by extracting hierarchical, translational-invariant features. In this paper, by designing one dimensional convolutional neural network (1-D CNN) which was further tIn the task of White Dwarf+Main Sequence (WDMS) finding in massive spectral data release, convolution can significantly improve the classification accuracy by extracting hierarchical, translational-invariant features. In this paper, by designing one dimensional convolutional neural network (1-D CNN) which was further trained in a discriminative, supervised way, 12 kernels with stable numerical distributions were produced, helping to generate spectral feature maps of WDMS. To solve the problem brought by biased sampling in the WDMS training set, we proposed a learning principle called Anti-Bayesian Learning Paradigm (ALP) which was built on the basis of order statistics by implying a comparatively looser prior distribution of spectral types. And in the way of separating training spectra into several groups according to their signal-to-noise ratios (SNR), we analyzed the robustness of convolutional extraction process to spectral noise. Experimental results indicated that, (1) WDMS classification with 1-D CNN and ALP reached the accuracy of 99.0%±0.3%, which outperformed the classic PCA+SVM model. (2) Pooling after convolution operations relieved the negative impact of spectral noise by lowering resolution. (3) When the SNR was less than 3, more epochs were required to learn stable kernels; when the SNR was between 3 and 6, the spectral convolutional features was stable; when the SNR was greater than 6, the convolution process acquired higher stability to eliminate the negative impact of SNR on model performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2962 (2018)
Analysis of Stray Light Influence to Modulation on Fourier Transform Spectrometer
CHEN Fang, GAO Chao, and XU Peng-mei
In the remote sensing application, the interferometer, especially Fourier Transform Spectrometer, is required to be of high spectral resolution and high signal to noise (SNR). Therefore, the modulation reduction caused by stray light, which is introduced by multiple reflections of beam splitter and compensator, has beeIn the remote sensing application, the interferometer, especially Fourier Transform Spectrometer, is required to be of high spectral resolution and high signal to noise (SNR). Therefore, the modulation reduction caused by stray light, which is introduced by multiple reflections of beam splitter and compensator, has been analyzed in detail in this paper. Based on theoretical analysis, the wedge angle and inclination angle are respectively introduced in beam splitter and compensator, which can reduce or even eliminate the influence of stray light by spot separation. The relationships among spot separation angle, wedge angle and inclination angle are given by theoretical formula, which can be used to optimize wedge angle and inclination angle. For the connection of structural parameters, the angle of incidence need to be adjusted with the wedge angle and inclination angle to keep the symmetry of reflected light and transmission light about splitting surface and eliminate the effect on spectral resolution. And then, the thickness of compensator also need to be adjusted, for eliminating the effect of optical path difference changing of regular optical light. The influence of the multiple reflections stray light can be eliminated by following these steps. Therefore, an optimization design method is obtained, which is suitable for the Fourier transform spectrometer using the beam splitter and compensator scheme..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2966 (2018)
Research on a Novel Static Imaging Spectrometer
HAO Li-hua, LU Xiao-dong, and WANG Ming-quan
The static interference system has the advantages of good stability and strong anti-interference ability, as well as disadvantages of low spectral resolution, nonadjustable spectral resolution, and so on. Aiming at such shortcomings of static interferometric imaging spectroscopy systems, a novel static imaging spectrosThe static interference system has the advantages of good stability and strong anti-interference ability, as well as disadvantages of low spectral resolution, nonadjustable spectral resolution, and so on. Aiming at such shortcomings of static interferometric imaging spectroscopy systems, a novel static imaging spectroscopy system is designed in this paper. The system consists of a beam shaping module, a novel static interference modulation module and an imaging module. The beam shaping module is used to shrink and shape the incident light into parallel light, so as to ensure a better interference effect. In addition, the novel static interference modulation module is used to coherently process incident light. The birefringence interference structure is modified in the system. On the basis of unchanged size of the original static interference, the spectral resolution of the system is improved, and the static modulation of the spectral resolution is realized. The imaging module is used to acquire two-dimensional visible images of the target area. The core components of the system consist of two sets of Wollaston prisms, as a spectral device, whose optical axes are orthogonal to each other. The electro-optical modulation module is placed between the two prisms for static scanning of the optical path. Besides, the working principle of the new static imaging spectroscopy system is introduced, and the system data model is given. The function expressions of the main parameters such as angle of incidence and angle of refraction are given, and the system data model is constructed. By plotting ray tracing graphs of the system, the functional equations of the lateral shear of the system are obtained, and the parameters that affect the lateral shear are analyzed and discussed respectively. The extent to which the parameter’s changes of structural angle, crystal thickness and modulation degree affect lateral shear is calculated by simulation. And the extent to which the parameter’s changes of structural angle, crystal thickness affect the spectral resolution is calculated quantitatively. Accordingly, a larger optical path difference can be achieved by appropriately increasing the structural angle and the crystal thickness. Therefore, it is feasible to realize the static scanning of lateral shear by means of electro-optic modulation, by which the acquisition of static spectral images can be achieved. In the experiment, 660 nm laser is tested. Two Wollaston prisms with opposite optical axes (Aperture: 20 mm×20 mm, thickness: 10 mm) and electro-optic modulated crystals (Thickness: 10 mm) are used in the novel static interference module. When modulation degree is 0.000 2 and 0.000 6 respectively, there are obvious differences in the interference fringes obtained by the imaging module. That the density of the interference fringe increases with the increase of modulation degree shows that the greater the modulation degree is, the stronger the spectral static scanning ability is, the more easily the spectral resolution is controlled. Thus, the static imaging spectroscopy system is characterized by adjustable spectral resolution under the condition of controlling the electro-optic crystal modulation degree. The feasibility of the system is verified..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2971 (2018)
Noise Analysis and Processing Method of Environment Monitoring Instrument
ZHANG Quan, HUANG Shu-hua, TIAN Yu-ze, LU Yue-lin, ZHAO Min-jie, ZHOU Hai-jin, ZHAO Xin, WANG Yu, and SI Fu-qi
The noise has a significant effect on the Signal to Ratio(SNR) of the trace gas absorption spectrometer, which is a standard for evaluating the imaging quality and trace gas retrieving capability. To quantitatively assess factors affecting SNR, and remove the noise of the spectrometer system, the noise source of the spThe noise has a significant effect on the Signal to Ratio(SNR) of the trace gas absorption spectrometer, which is a standard for evaluating the imaging quality and trace gas retrieving capability. To quantitatively assess factors affecting SNR, and remove the noise of the spectrometer system, the noise source of the spectrometer is analyzed and the corresponding noise model is given. On this basis, the SNR model of the spectrometer is established in this paper. In addition, the effects of incident light intensity, integration time and system gain on the SNR are studied. The relationship between the different operating modes and different parameters and SNR is verified by the calibration experiment data of the spectrometer. And the main system noise is proposed: the linear deviation is used to determine the system offset noise. Besides, the temperature correction factor is obtained by using the dark current temperature correlation on the ground to realize the load in-orbit dark current correction. In the linear range of the detector response PRNU noise is corrected by the two-point correction method. The results show that the DN value of UV1 channel electronic offset noise is 2 625, and UV2 is 2 763. The dark current noise is the main part when the CCD imaging surface temperature is higher than 0 ℃, The temperature decreases to -20 ℃ when the rest of the noise plays a leading role to verify the best cooling temperature of the CCD; SNR increases with the increasing incident light response and integration time, the system gain will not affect SNR; PRNU noise was significantly improved by correction, decreasing from 3.32% to 0.47%, improving the spectral quality of the spectrometer. The noise analysis and processing methods are conducive to trace gas retrieve of further spectral data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2976 (2018)
Structural, Optical and Electrochromic Properties of WO3 Thin Films Prepared by Chemical Spray Pyrolysis Versus Spin Coating Technique
S. Morko Karadeniz, Demet Tatar, M. Erturul, and A. E. Ekinci
In this study, Tungsten Oxide (WO3) thin films were prepared by Chemical Spray Pyrolysis (CSP) and Spin Coating (SC) techniques and it was investigated effects of technique and parameter on the films. WO3 thin films were deposited on ITO (Indium Tin Oxide) coated glasses. The structural, optical and electrochromic propIn this study, Tungsten Oxide (WO3) thin films were prepared by Chemical Spray Pyrolysis (CSP) and Spin Coating (SC) techniques and it was investigated effects of technique and parameter on the films. WO3 thin films were deposited on ITO (Indium Tin Oxide) coated glasses. The structural, optical and electrochromic properties of the WO3 thin films were characterized by XRD, SEM, UV, and CV measurements. The sharpest (200) peak was observed in the XRD spectra and optical band gaps were calculated around 2.6～3.1 eV via UV-Vis spectra for all of the samples. Micro fibrous reticulated surface (filamentous like) morphology for the films deposited by CSP technique and smooth surface morphology with high optical transmittance for the film deposited by SC Technique were obtained from SEM images. In addition to these results, it was revealed that all the samples exhibit good electrochromic performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 2982 (2018)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 1 (2018)
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