Journals >Spectroscopy and Spectral Analysis
Contents
2020
Volume: 40 Issue 5
59 Article(s)
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Universal Formula of Blackbody Waveband Radiation Brightness Response in the Infrared Temperature Measurement Technology
CUI Shuang-long, SUN Bo-jun, and SUN Xiao-gang
Based on the infrared temperature measurement technology, this paper focuses on the model ｆ(Ｔ)＝∫λ２λ１ＲλＬｂλ(Ｔ)ｄλ≈ＣＴｎ. This model represents the response of blackbody radiation brightness on the detector in a certain wavelength range, which is called the blackbody waveband radiation brightness response in this paper. For Based on the infrared temperature measurement technology, this paper focuses on the model ｆ(Ｔ)＝∫λ２λ１ＲλＬｂλ(Ｔ)ｄλ≈ＣＴｎ. This model represents the response of blackbody radiation brightness on the detector in a certain wavelength range, which is called the blackbody waveband radiation brightness response in this paper. For different detectors, different wavelength ranges, different temperature ranges, there are different C and n. The value of n is difficult to obtain accurately. Most researchers used the three fitting results of C and n proposed by Inagaki T and Okamoto Y in 1996, and the results could not be well extended to any waveband detectors. In this paper, by using the Wien Approximation Formula to replace Planck’s formula, the analytical formula of ｆ(Ｔ) is theoretically derived which is a universal formula of ｆ(Ｔ), so that we can obtain the blackbody waveband radiation brightness response ｆ(Ｔ) in any waveband through theoretical calculations. The universal formula is applied in simulations. Simulation 1: Integrate the universal formula in the whole waveband to obtain an analytical formula Mbb=5.238 5×10－8T4, and compare it with Stephen Boltzmann’s law. The difference between the coefficient σ′=5.238 5×10－8 obtained by the universal formula and the Stefan Boltzmann constant σ=5.667 9×10－8 is 0.429 4×10－8. Simulation 2: Acquire the spectral responsivity of the HgCdTe detector with an effective wavelength of 8~13 μm from reference [2], calculate the blackbody waveband radiation brightness response ｆ(Ｔ) of the detector in the 8~13 μm band, plot the result to compared with f(T)≈0.136×σT4. 09 shown in reference [2], and the results are basically the same. Two simulations illustrate the correctness of the analytical formula. On this basis, further experimental verification is performed. A surface source radiator in the laboratory was applied as the target. Through the universal formula, the emissivity of target ε can be calculated and compared with the reference value of true emissivity of target ε0. Experimental results of the surface source radiator: ０＝0.92 is the reference value of true target emissivity, ０＝0.93 is measured value, the error of emissivity is 0.01. The small error indicates that the model proposed in this paper can be used in the engineering practice of infrared temperature measurement technology. In this paper, a universal formula that can replace the model ｆ(Ｔ)≈ＣＴｎ is proposed. Compared with the original model, the greatest advantage of the universal formula is that it can be applied in any waveband without considering the temperature partition and it is a universality to calculate the blackbody waveband radiation brightness response by theoretical calculation. The universal formula further perfects the basic theory of infrared temperature measurement technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1329 (2020)
Investigation of Transmission Characteristic of O+ 83.4 nm Dayglow in the Ionosphere
WANG Da-xin, FU Li-ping, JIANG Fang, JIA Nan, and DOU Shuang-tuan
Extreme Ultraviolet (10～100 nm) dayglow emission is produced primarily by photoionization excitation and photoelectron impact ionization. Observing extreme ultraviolet dayglow by using space-based remote sensing, we can obtain the information of electron density, ion density and spatial distribution of ionospheric F laExtreme Ultraviolet (10～100 nm) dayglow emission is produced primarily by photoionization excitation and photoelectron impact ionization. Observing extreme ultraviolet dayglow by using space-based remote sensing, we can obtain the information of electron density, ion density and spatial distribution of ionospheric F layer in the daytime. The EUV dayglow remote sensing technology started earlier in foreign countries, especially in Europe, America, Japan and other countries, and have come to maturity now. However, there are very few studies on EUV dayglow remote sensing in China, and the detection of ionosphere is mainly at night. For example, the ionospheric photometer loaded on the D-Star of the FengYun-3 meteorological satellite launched by China in 2017 can obtain the nighttime ionospheric peak electron density. Remote sensing in extreme ultraviolet (EUV) emission, especially the detection of the radiation characteristics of O+ ion 83.4 nm in the ionosphere, is an important means to obtain daytime ionospheric radiation characteristics, and is also the research hotspot of ionospheric optical remote sensing in the world. Firstly, we have studied the main radiative transfer theory of EUV dayglow in this paper, and introduces the excitation process, impact ionization process and multiple resonant scattering process. On this basis, we focus on the generation mechanism and radiation transmission characteristics of 83.4 nm dayglow. O+ 83.4 nm dayglow is generated by photoionization of the O atoms in the low thermosphere by solar EUV and is the brightest emission in EUV. The altitude distribution of the 83.4 nm dayglow can provide some information about the density profile of the O+ ions, and by charge neutrality, the electron density, which provide an effective method for ionospheric detection in the daytime. Secondly, we have analyzed the band characteristics of 83.4 nm dayglow. Based on the Mass Spectrometer Incoherent Scatter (MSIS-00) model, we calculate the initial volume emission rates, the volume emission rates under resonant scattering and limb column emission intensity of 83.4 nm dayglow emission by using the AURIC v1.2 model, and then we analyze the correlation with altitude, latitude, solar activity index, geomagnetic activity index and so on. Based on the extreme ultraviolet radiation algorithm, and the particularity of the radiation transmission at O+ ion 83.4 nm, considering the multiple scattering effects of the radiation, the radiation calculation method of oxygen ion 83.4 nm dayglow is proposed. Assuming that the ionosphere is electrical neutrality, the O+ density of the ionosphere in the daytime can be inverted by obtaining the EUV dayglow intensity of oxygen ion 83.4 nm, and then we can obtain the electron density distribution of the ionosphere F layer in the daytime, providing an important basis for studying the radiation transmission characteristics of the daytime ionosphere..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1334 (2020)
High Accurate Spatially Resolved Measurements of Discharges Plasma Spectra
TIAN Yi-fu, LI Bo, GAO Qiang, ZHU Zhi-feng, ZHU Jia-jian, and LI Zhong-shan
Discharge plasma spectroscopy and laser-induced breakdown spectroscopy are widely used in the flow field diagnostics owing their simplicity and strong signal intensity. Due to the random nature of the discharge, the time and space of the discharge are hard to be controlled, so it is difficult to measure the discharge pDischarge plasma spectroscopy and laser-induced breakdown spectroscopy are widely used in the flow field diagnostics owing their simplicity and strong signal intensity. Due to the random nature of the discharge, the time and space of the discharge are hard to be controlled, so it is difficult to measure the discharge plasma spectra accurately, and the laser-induced breakdown spectroscopy is limited to point measurements. In this paper, we introduce a method of one-dimensional spatially resolved discharge plasma spectra measurements, based on femtosecond laser filamentation-guided discharge. Femtosecond lasers beam self-focusing could create a filamentous weak plasma channel, and this weak plasma channel can be used as a trigger source for the high voltage discharge when it is close to the pair of high voltage electrodes. This triggering way can trigger and guide the discharge to breakdown the air along the path of the plasma channel at a specified time. Under the experimental conditions, the fluctuation of the time interval between laser pulse arriving and the start of discharge is less than 0.01 μs, which indicates that the laser filamentation-guided discharge is highly repeatable. Therefore, using the femtosecond laser can realize the precise control of the time and space of the discharge, and one-dimensional spatially resolved spectra of discharge plasma can be accurately collected. In a jet flow field environment, the mixture fraction in the jet is different from the ambient air. The experimental results show that the changes in the species concentration at different locations can be seen clearly from one-dimensional spatially resolved spectra. By correlating the concentrations of N2 and O2 with the signal intensity of N+ and O atom, one can realize a one-dimensional measurements of the species concentration. Compared with nanosecond laser-induced breakdown spectroscopy, this method not only has the same advantages, but also has one-dimensional spatial resolution. Meanwhile, this method has the potential to achieve high temporally resolved measurement, which is of great significance for studying the spatiotemporal evolution process of the discharge plasma..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1340 (2020)
Study on the Surface Plasmon Resonance of Square and Ring/Disc Array Structure
CAO Wen, PAN Ting-ting, DENG Ya-li, LI Mei, HAO Hui, XIA Wei, and WANG Ming
Local surface plasmon resonance is a kind of resonance phenomenon caused by collective oscillation of free electrons on the surface of metal nanoparticles under the action of photons. A kind of square and ring/disk array structure is proposed in this paper, which is composed of the left single ring, the right square anLocal surface plasmon resonance is a kind of resonance phenomenon caused by collective oscillation of free electrons on the surface of metal nanoparticles under the action of photons. A kind of square and ring/disk array structure is proposed in this paper, which is composed of the left single ring, the right square and the eccentric ring disk. The optical properties of the structure are investigated by the finite difference time domain (FDTD) method. Fano resonances appear in the transmission spectra due to the electric field couplings between the arrays when linearly polarized light is incident to the metal surface. Obvious resonant valley characteristics are formed at different positions in the wavelength range of 600～1 700 nm. Comparison and analysis of electric field and charge simulation diagram, it is found Fano resonance is formed by the coherent interference between the dipole resonance of the ring and the four dipole resonance modes excited by the square and the ring/disk. The local surface plasmon resonance between metal nanoparticles changed by the coupling effect of the electric field. Therefore, the Fano resonance is dependent on the parameters of the structure (such as the diameter of the left ring L, the diameter of the right ring R, the height of the structure H, the distance from the left ring to the square D, etc. ). By changing the parameters of the structure, the wavelength position and the resonant intensity of the resonant valley can be effectively controlled and the optical properties also can be controlled. Because of the unique asymmetry of the structure, the influence of the polarization direction of the incident light source (the angle between the electric vector and the x axis) on the position of the resonant valley wavelength and the resonant intensity of the structure is further investigated. The structure shows that with the increase of the polarization angle of the light source, the wavelength position at the resonant valley J2 appears obvious red shift phenomenon. However, when the polarization angle is 90°, the Fano resonance can not occur at the resonance valley J3. Therefore, the resonant intensity and the resonant wavelength position of the structure can be controlled by changing the polarization direction of the light source. More importantly, the structure has a high sensitivity to the environmental refractive index, up to 755 nm·RIU-1, and the figure of merit (FOM) can reach 18.4. The results show that the structure has potential application prospects in the applications of environmental refractive index sensors and micro-nanophotonic devices..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1345 (2020)
Geometrical Optimization of Resonant Ellipsoidal Photoacoustic Cell in Photoacoustic Spectroscopy System
WANG Qiao-yun, YIN Xiang-yu, YANG Lei, and XING Ling-yu
Real-time gas detection is of great significance in manyfields, such as petrochemical industry, modern industry, environment, medical diagnosis, transformers. Photoacoustic spectroscopy (PAS) gas detection technology is a gas detection technology based on the PA effect. It has been widely used in tracegas detection becReal-time gas detection is of great significance in manyfields, such as petrochemical industry, modern industry, environment, medical diagnosis, transformers. Photoacoustic spectroscopy (PAS) gas detection technology is a gas detection technology based on the PA effect. It has been widely used in tracegas detection because of its high detection sensitivity, high selectivity, high resolution, wide detection range and real-time monitoring. The PA cell is the most important componentof the PAS system.And the sensitivity and resolution of the system are directly affected by PA cell. The standard cylindrical structure of the resonance the PA cell is a common choice, and the detection sensitivity and resolution of the system are mainly improved by the microphone. In this paper, a high-sensitivity ellipsoidal resonant photoacoustic cell is proposed for the first time. Combining with the theory of gas thermodynamics and acoustics, the finite element method of ellipsoidal photoacoustic cell and traditional cylindrical photoacoustic cell is analyzed by COMSOL software, its acoustic feature model is established. The acoustic characteristics of the photoacoustic cell,such as resonance frequency, the sound pressure distribution in the cavity of the photoacoustic cell, and the acoustic pressure level are simulated. The relationship between resonance frequency, sound pressure, the size of ellipsoidal, cylindrical photoacoustic cell and the length and center radius of the ellipsoidal photoacoustic cell is simulated. The optimal length and center radius ofthe ellipsoidal photoacoustic cell is 100 and 5 mm, respectively. Compared with a conventional cylindrical photoacoustic cell, the resonant frequency of the ellipsoidal photoacoustic cell is 1 340 Hz and the cylindrical photoacoustic cell is 1 650 Hz. The sound pressure signal generated in the resonance state is about 5.01×10-5 Pa and the cylindrical photoacoustic cell is 5.7×10-6 Pa. The sound pressure level is 11 dB and the cylindrical photoacoustic cell is -13.9 dB. The Q-factor is 70 and the cylindrical photoacoustic cell is 66. The results show that the resonant frequency of the ellipsoidal photoacoustic cell is less than that of the cylindrical photoacoustic cell, and the maximum sound pressure signal is about 9 times that of the same size cylindrical resonant photoacoustic cell, and the sound pressure level is increased from -13.9 to 11 dB. The ellipsoidal resonant photoacoustic cell has small volume, large acoustic pressure signal, high detection sensitivity, and the performance of the photoacoustic cell has been improved significantly. This structurecan improve the sensitivity of photoacoustic spectroscopy for the detection of trace gases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1351 (2020)
Research Progress in the Application of UAV Spectral Imaging Technology in Field
PENG Yao-qi, XIAO Ying-xin, ZHENG Yong-jun, YAN Hai-jun, DONG Yu-hong, and LI Xin-xing
Traditional methods of crop monitoring in the field need to lay various sensors and complex circuits in the field with a bad environment. Usually, the problems of time-consuming, labor-consuming, high maintenance cost and more or less damage to plants arise. Unmanned aerial vehicle (UAV) spectral imaging technology is Traditional methods of crop monitoring in the field need to lay various sensors and complex circuits in the field with a bad environment. Usually, the problems of time-consuming, labor-consuming, high maintenance cost and more or less damage to plants arise. Unmanned aerial vehicle (UAV) spectral imaging technology is a new and fast technology for monitoring farmland environment, which combines an unmanned aerial vehicle (UAV), remote sensing sensors, real-time image transmission and other means. It can quickly obtain real-time spectral images of farmland crops. Usually, it can analyze images to obtain the growth information of farmland crops. The application of this technology catches up with the above problems. Firstly, the spectrum imaging technology of UAV is summarized, and the advantages of UAV application are introduced. Compared with traditional satellite remote sensing monitoring platform, UAV can work at a lower altitude, i. e. 80～400 m. It can resist the disadvantage of adverse weather and clouds, and achieve fast and accurate acquisition of high-precision images. At present, the application of small UAVs at home and abroad mainly focuses on disaster monitoring, natural resources monitoring, urban planning and vegetation monitoring. In addition, due to its low cost, near real-time image acquisition and other characteristics, in the development of precision agriculture, unmanned aerial vehicle (UAV) spectral images are more commonly used. Secondly, the characteristics and application scenarios of common spectral images are analyzed. Panchromatic images are mostly used for data fusion because of their high resolution; multispectral and hypersecretion images are combined with spectral characteristics of crops due to their abundant spectral information, which can be used for the detection of biological and chemical indicators of crops, early warning of agricultural disasters, yield prediction and fine classification mapping; and thermal infrared images can be used for monitoring field drought because they can obtain crop temperature information. Then the main application ways of UAV spectral image technology in the field are summarized. At present, the main methods of monitoring crops using UAV spectral image technology are: using spectral reflectance to construct vegetation index or red edge parameters, or studying the reflection characteristics of vegetation, constructing crop growth model, using multiple linear regression, partial least squares method, in-depth learning and other biochemical parameters of crops to establish a model for inversion. Finally, shortcomings of UAV spectral imaging technology in the field application are discussed, and the future development prospects of this new technology have prospected, in order to provide a reference for the derivative application of UAV spectral imaging technology in the field..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1356 (2020)
Spectral Radiation Transmission Model of Plasma in Laser Welding
WANG Nian, SHEN Hua, and ZHU Ri-hong
Understanding the distribution of the spectral radiation field of laser-induced plasma at multiple wavelengths will be helpful to acquire the distribution of the temperature field, electron density and other physical quantities of the plasma, which is significant for improving the laser welding process. Making clear thUnderstanding the distribution of the spectral radiation field of laser-induced plasma at multiple wavelengths will be helpful to acquire the distribution of the temperature field, electron density and other physical quantities of the plasma, which is significant for improving the laser welding process. Making clear the physical process of how spectral radiation transfers to detector target is the premise of reconstructing spectral radiation field of plasma. In this paper, a spectral radiation transmission model of plasma in laser welding based on optical imaging is proposed: By studying the process that plasma spectral radiation emitting to the lens of the detector based on radiometry, the coefficient ω1 that the spectral radiation received by the lens taking up that emitting to the surrounding space of a point in the plasma is deduced so that the spectral radiation transfer model is established; by studying the imaging process that spectral radiation emits from plasma through the lens to the detector target based on the principle of optical imaging, the coefficient ω2 that the spectral radiation received by a pixel taking up that received by the lens is deduced so that an optical imaging model is established. Then the spectral radiation ratio coefficient ω is obtained with ω1 and ω2, thus the spectral radiation transmission model is established. Through simulation experiments, the effect of spectral radiation field reconstruction of laser welding plasma with symmetrical and asymmetrical temperature distribution between 1 000 and 3 000 ℃ was investigated. The results showed that the reconstruction accuracy with the model presented is 5.39%, 6.5%, 7.25% and 6.11% for the plasma with symmetrical temperature distribution at 400, 500, 600 and 700 nm respectively, and 9.34%, 10.07%, 10.68% and 9.72% for that with asymmetrical temperature distribution, which means the proposed model can be used for reconstructing the spectral radiation field of laser welding plasma at 400～700 nm well. Compared with other models, this model has better reconstruction accuracy and can meet the needs of industrial applications..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1362 (2020)
Raman Spectra of KCl—O2 at High Pressure and High Temperature
TIAN Yu, XIAO Wan-sheng, TAN Da-yong, HE Yun-hong, ZHAO Hui-fang, and JIANG Feng
The chemical reaction of KCl—O2 system was studied under high pressure and high temperature by using the diamond anvil cell and the laser heating technology. The KCl—O2 sample was heated at 37 GPa ［(1 800±200) K］and then the products were measured by Raman technology at ambient temperature. The Raman test results The chemical reaction of KCl—O2 system was studied under high pressure and high temperature by using the diamond anvil cell and the laser heating technology. The KCl—O2 sample was heated at 37 GPa ［(1 800±200) K］and then the products were measured by Raman technology at ambient temperature. The Raman test results show that the KCl—O2 system undergoes a chemical reaction at high pressure and high temperature, producing a non-conventional compound KCl3 with a trigonal (P-3c1) structure, a small amount of KClO4, solid Cl2 (Cmca), and possibly existing another non-traditional compound KO4. In this experiment, 11 Raman vibration peaks of P-3c1-KCl3 were measured under high pressure. According to the theoretical calculation of the Raman spectrum of P-3c1-KCl3 in the first principle, the 11 Raman vibration peaks were assigned to the vibration modes. The P-3c1-KCl3 gradually weakens on decompression, and decomposes into KCl and Cl2 below 10 GPa, indicating that P-3c1-KCl3 cannot be stored under ambient pressure. It is difficult to detect the Raman peak of KO4for being disturbed by the Raman peak of diamond under high pressure, and the three Raman vibration peaks of KO4 are detected after opening the diamond anvil cell under ambient pressure. Experiments have shown that the moisture-absorbing KO4 black powder can be stored at ambient pressure. The emergence of novel chemical reaction products of KCl3 and KO4 shows that high pressure promotes oxygen and chlorine forming unconventional pair-anions (O—O pair-anions) and polyanions (Cl—Cl—Cl polyanions) with the negative charge of the fraction, indicating that the two elements have unconventional chemical properties under high pressure. Experiments have also shown that there are several unusual chemical reactions under high pressure. The oxidation state of the reactants and products shows that O gains electrons from zero to negative valence, while Cl loses electrons from negative valence to zero or positive valence state, reflecting that O is more electron-friendly than Cl. These novel chemical reactionsprovide a new pathway to synthesize the polyhalide anions compounds that may have exotic properties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1367 (2020)
Raman, IR and DFT Studies of Gatifloxacin
XU Di, FAN Ya, XIN Min-si, LIU Chun-yu, ZHANG Ye, and CAI Hong-xing
Gatifloxacin is widely used as a fourth-generation fluoroquinolone antibiotic, and it has drug residues in humans and livestock, which endangers everyone’s life and health. In order to avoid secondary intake, it is particularly important to be able to detect the presence of gatifloxacin residues in meat products quicklGatifloxacin is widely used as a fourth-generation fluoroquinolone antibiotic, and it has drug residues in humans and livestock, which endangers everyone’s life and health. In order to avoid secondary intake, it is particularly important to be able to detect the presence of gatifloxacin residues in meat products quickly.To this end, this paper uses vibrational spectroscopy combined with density functional theory to provide basic data for the vibrational spectroscopy detection and identification of gatifloxacin and provides a reference for its application in the field of drug detection. The specific research contents and results are as follows: The first step is to construct the molecular structure of gatifloxacin based on Density functional theory (DFT), and optimize the structure by using B3LYP/6-311+G(d) basis set. Calculate its theoretical Raman and infrared spectra. Theoretical calculations show that the gatifloxacin molecule has obvious Raman and infrared activity in the range of 3 700~2 800 and 1 800~400 cm-1. The former is mainly the vibration of the upper group of the functional group, and the latter is the fingerprint area. The vibration of the upper button. Due to the superiority of the complementary information of the two kinds of spectral information, firstly, by comparing the theoretical Raman spectrum and the infrared spectrum, the vibration peak frequency of two or only one vibration activity is marked, and the Gaussian view is combined with each of the gatifloxacin molecules. The vibration frequency corresponding to each key is fully attributed, and the spatial structure parameters such as the bond length, bond angle and dihedral angle of the gatifloxacin molecule are given. In the second step, the natural Raman spectroscopy (NRS) and infrared spectroscopy (IR) of Gatifloxacin (Gati) were measured experimentally. The theoretical calculation result error is corrected by the frequency correction factor of 0.977 and compared with the experimental data. In the fingerprint area, the Raman and infrared characteristic peak wave number matching degree are good. The peak wave number difference is mostly in the range of 0~10 cm-1. The calculation results are basically consistent with the experimental data. The results provide basic data for the vibrational spectrum detection and identification of gatifloxacin, and provide a reference for its application in the field of drug detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1372 (2020)
Study on Spectral Radiation Characteristics of Carbon Disulfide Flame Based on Infrared Spectroscopy
NING Jia-lian, TANG Jin, HU Tian-you, LIU Qiang, WANG Hao-wen, and CHEN Zhi-li
In recent years, the demand for carbon disulfide in the chemical industry is increasing, and carbon disulfide is flammable and explosive. In the production process, fire accidents of carbon disulfide are prone to occur, which are extremely harmful and easy to cause economic losses and casualties. In the study of fire aIn recent years, the demand for carbon disulfide in the chemical industry is increasing, and carbon disulfide is flammable and explosive. In the production process, fire accidents of carbon disulfide are prone to occur, which are extremely harmful and easy to cause economic losses and casualties. In the study of fire accident hazard, the flame spectrum research is very necessary. Because the flame spectrum contains much information, including flame temperature, combustion components, thermal radiation intensity of each band, etc., it is necessary to conduct an in-depth study of its flame spectral radiation. In this paper, carbon disulfide as the research object, and the flame spectrum test platform was built based on infrared spectroscopy. The test platform was mainly composed of VSR infrared spectrometer, telescopic device and burner. The carbon disulfide, styrene, acetonitrile and ethyl acetate were tested at 5 cm combustion scale. The combustion flame spectrum of carbon disulfide, styrene, acetonitrile and ethyl acetate fuels in the infrared range of 1～14 μm was tested at 5 cm combustion scale, and the carbon disulfide was mixed with styrene, acetonitrile and ethyl acetate in 1∶1. Flame spectrum, the characteristic band of carbon disulfide flame spectrum was obtained, and the carbon dioxide flame spectrum characteristic database was constructed. In the study of fuel flame spectrum, the carbon dioxide flame is blue when it burns, and does not smoke, it is flame spectrum radiation mainly comes from three kinds of molecular radiations of SO2, CO2 and H2O at high temperature. The characteristic peak of SO2 is 4.05, 7.4 and 8.51 μm, CO2 characteristic peak is 2.7 and 4.3 μm, H2O characteristic peak is 2.5, 2.7 and 5.5～7 μm. The spectral characteristics of acetonitrile and ethyl acetate fuel combustion flames are basically similar. The flame spectrum radiation mainly comes from CO2 and H2O molecular radiation at high temperature. In addition to high-temperature gas radiation, styrene flame spectrum radiation has strong carbon black radiation, the carbon black has a center wavelength of 7 μm and a temperature of about 414 K. In addition, styrene fuel has a unique C—H* stretching peak at 3.6 μm compared to the other three chemicals. Compared with the flame spectrum characteristics of styrene, acetonitrile and ethyl acetate, the carbon disulfide flame spectrum has unique characteristic peaks at 4.05, 7.4 and 8.51 μm, which are generated by SO2 molecules. These characteristic peaks can be used as one of the fire bases for space exploration. In the study of fuel mixed combustion flame spectroscopy, when carbon disulfide is mixed with styrene, acetonitrile and ethyl acetate, the combustion flame spectrum characteristics are basically similar. The flame spectrum radiation mainly comes from CO2, H2O and SO2 molecular radiation at high temperature. The experimental results also show that in the mixed combustion, the flame spectral characteristic peak of carbon disulfide is not interfered by the components of other fuels, and the characteristic peak is still obvious. This result can lay a foundation for the research on detecting and identifying carbon disulfide fire using space remote sensing detection technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1377 (2020)
A Simplified Method of Microscopic Hyperpolarizability of Coherent Anti-Stokes Raman Spectroscopy and Coherent Anti-Stokes Hyper-Raman Spectroscopy-C3v Symmetry
WANG Yuan, ZHANG Zhen, and GUO Yuan
Coherent Anti-Stokes Raman Spectroscopy (CARS) and Coherent Anti-Stokes Hyper-Raman Spectroscopy (CAHRS) recently have been widely used in the study of the spectral properties of molecules, the structure of tumor cells and the dynamics of molecular reactions. However, the main difficulty in quantitative analysis CARS aCoherent Anti-Stokes Raman Spectroscopy (CARS) and Coherent Anti-Stokes Hyper-Raman Spectroscopy (CAHRS) recently have been widely used in the study of the spectral properties of molecules, the structure of tumor cells and the dynamics of molecular reactions. However, the main difficulty in quantitative analysis CARS and CAHRS is that the number of molecular, microscopic hyperpolarizability tensors in the high order nonlinear optical process are large and the relationships are complex. Our previous work has reported the simplification schemefor CARS and CAHRS microscopic hyperpolarizability tensor elementsbased on the C∞v molecular symmetry. In this paper, we present the simplified scheme for microscopic hyperpolarizability tensor elements of CARS and CAHRS belonging to the C3v symmetry. First, the tensor elements βi′j′k′l′ of the CARS microscopic hyperpolarizability are expressed as the product of the differentiation of Raman microscopic polarizability tensor α′i′j′. The CAHRS microscopic hyperpolarizability tensor elements βi′j′k′l′m′ are expressed as the product of the differentiation of Raman microscopic polarizability tensor α′i′j′ and the differentiation of hyper Raman microscopic polarizability tensor β′i′j′k′. The ratio between βi′j′k′l′ and βi′j′k′l′m′ can be simplified by using the ratio between α′i′j′ and β′i′j′k′. For the symmetric vibrational mode A1 of C3v symmetric type molecular groups, 9 non-zero and 3 independent CARS microscopic hyperpolarizability tensors can be described by a ratio between RRSS and α′i′j′, and 21 non-zero and 6 independent CAHRS microscopic hyperpolarizability tensors can be described by three ratios of RRSS, RHRSS, 1 and RHRSS, 2 between α′i′j′ and β′i′j′k′. Then, the Bond Additivity Model method is used to calculate the coupling between every single bond in the C3v symmetric molecular group, from which the ratio of hyper Raman microscopic polarizability tensor differential β′i′j′k′ for the symmetric vibrational mode A1 of C3v symmetric type molecular groups is obtained. Combined with the ratio of the Raman microscopic polarizability tensor differential α′i′j′ component given in the literature, the relationship between the CARS and CAHRS microscopic hyperpolarizability tensors of C3v symmetry molecular group is further simplified. These relationships between the microscopic hyperpolarizability tensor elements of CARS and CAHRS obtained in this paper are ready to be used for simplifying the expression of CARS and CAHRS signals and generalized oriented functional RIJK(θ), whichcan obtain the variation of RIJK(θ) with the orientation angle θ of the interface molecule group. Furthermore, the expressions of intensity factor dIJK, generalized oriented functional RIJK(θ) and generalized orientation parameters c2 and c4 are obtained. This work provides a theoretical basis for quantitative analysis of interface molecular orientation information..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1382 (2020)
Structures, Stablity and Spectroscopic Property of Chromium Doped Silicon Clusters
LIN Lin, YANG Ju-cai, YING Chun, LI Ji-jun, and ZHAO Er-jun
The structures, stability and spectroscopic property of Chromium doped small silicon clusters CrSin (n=3～9) and their anions are systematically investigated using CCSD(T)/aug-cc-pVTZ-DK//MP2/6-31G(2df, p) and the B3LYP/ aug-cc-pVTZ basis set. The results show that the ground-state structures of neutral CrSin (n=3～9) anThe structures, stability and spectroscopic property of Chromium doped small silicon clusters CrSin (n=3～9) and their anions are systematically investigated using CCSD(T)/aug-cc-pVTZ-DK//MP2/6-31G(2df, p) and the B3LYP/ aug-cc-pVTZ basis set. The results show that the ground-state structures of neutral CrSin (n=3～9) and their anion are all exohedral structures. According to the calculated dissociation energies, it shows that when n<5, the neutral CrSin are less stable than their anion. And when n≥5, the CrSi5 and CrSi8 of neutral CrSin are more stable than their neighboring clusters; the CrSi4 and CrSi7 of anionic CrSin are less stable than their neighboring clusters. The VDEs of CrSin are predicted to be 2.26 eV for CrSi3, 3.21 eV for CrSi4, 2.72 eV for CrSi5, 3.54 eV for CrSi6, 2.45 eV for CrSi7, 2.71 eV for CrSi8 and 2.95 eV for CrSi9. They are in excellent agreement with experimental data except for CrSi4, the average absolute deviations from experimental data are only 0.073 eV. The AEAs of CrSin are evaluated to be 2.07 eV for CrSi3, 1.95 eV for CrSi4, 2.4 eV for CrSi5, 2.32 eV for CrSi6, 2.38 eV for CrSi7, 2.67 eV for CrSi8, and 2.63 eV for CrSi9. Except for CrSi6, they are in excellent agreement with experimental data. The average absolute deviations from experimental data are only 0.09 eV. Besides, the photoelectron spectra (PES) of ground-state structures of anionic CrSin (n=3～9) are simulated at the PBE1PBE/6-31G(2df, p) level, and compared to the corresponding experiment data, it is concluded that the ground-state structures obtained in this paper are reliable..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1388 (2020)
Spectral and Structural Investigation on Weak Interactions of Bipyridine/Pentafluorophenol and Bipyridine/Pentafluorobenzoic Acid Co-Crystals
HE Jian, LI Ai-sen, WANG Jing, XU Shu-ping, and XU Wei-qing
Pentafluoro phenol (PFP) and pentafluorobenzoic acid (PFBA) as ligands were combined with 4,4’-bipyridine (BP) to obtain two kinds of co-crystals, BP/PFP and BP/PFBA, respectively. Raman and infrared spectra of two co-crystals and their precursors were obtained. The relevant peaks were analyzed, with the help of the caPentafluoro phenol (PFP) and pentafluorobenzoic acid (PFBA) as ligands were combined with 4,4’-bipyridine (BP) to obtain two kinds of co-crystals, BP/PFP and BP/PFBA, respectively. Raman and infrared spectra of two co-crystals and their precursors were obtained. The relevant peaks were analyzed, with the help of the calculated spectra throughdensity functional theory (DFT). Infrared spectra show rich hydrogen bonds existed in these two co-crystals. Raman characterization indicates that hydrogen bonding in the BP/PFBA co-crystal is stronger than that in the BP/PFP. In addition, combined with infrared, Raman and crystal structure data, it is found that hydrogen bond and π-π interaction coexist in the BP/PFP co-crystal. The difference of weak interaction results in the difference of crystal structure. This study displays significance for further under standing of the structure and properties of co-crystals, which is helpful for the design of novel co-crystals..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1393 (2020)
Study on Atmospheric Temperature and Water-Vapor Mixing Ratio Based on Raman Lidar
TAN Min, WANG Bang-xin, ZHUANG Peng, ZHANG Zhan-ye, LI Lu, CHU Yu-fei, XIE Chen-bo, and WANG Ying-jian
Raman lidar has been designed by the Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, which measures atmospheric temperature, water vapor, and aerosol simultaneously. A high-performance spectroscopic box that utilizes multicavity interference filters, mounted sequentially at small angles of inRaman lidar has been designed by the Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, which measures atmospheric temperature, water vapor, and aerosol simultaneously. A high-performance spectroscopic box that utilizes multicavity interference filters, mounted sequentially at small angles of incidence, is used to separate the lidar return signals at different wavelengths, and to extract the signals with high efficiency. The external experiments are carried out for simultaneous detection of atmospheric temperature, water vapor, under clear and hazy weather conditions. The vertical profiles of temperature, water vapor are analyzed. The results show that for an integration time of 5 min and laser energy of 200 mJ, the mean deviation between measurements obtained by lidar and radiosonde is small, and the overall trend is similar. The temperature inversion layer is found in the low troposphere. The statistical temperature error for nighttime is below 1 K up to a height of 6.2 km under clear weather conditions, and up to a height of 2.5 km under slightly hazy weather conditions, with 5 min of observation time. Moreover, the relative error in water vapor detection process mostly does not exceed 5% up to 4 km, and is well below 20% up to 7.5 km. Continuous observations verify the reliability of Raman lidar to achieve real-time measurement of atmospheric parameters in the troposphere..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1397 (2020)
Study on Interaction Between Phenylethanolamine A and CdTe Nanomaterials by Fluorescence Spectroscopy
XIONG Yang, XU Jun, QIU Su-yan, WEI Yi-hua, and ZHANG Jin-yan
Phenylethanolamine A (PA) is a new adrenergic agonist and can improve feed utilization and the lean meat percentage of carcasses of livestock. But the drug residue would lead to a great threaten to human, such as nausea, dizziness,limbweakness, hand tremor and other symptoms of poisoning. Long-term consumption may leadPhenylethanolamine A (PA) is a new adrenergic agonist and can improve feed utilization and the lean meat percentage of carcasses of livestock. But the drug residue would lead to a great threaten to human, such as nausea, dizziness,limbweakness, hand tremor and other symptoms of poisoning. Long-term consumption may lead to mutations in the body’s chromosomes, induced malignant tumorsetc. At present, the main detection method is liquid chromatography-tandem mass spectrometry (LC-MS-MS). The interaction between PA and CdTe nanomaterials is rarely reported. In this study, the water-soluble CdTe nanomaterials were prepared by microwave heating method,using mercaptopropionic acid as a stabilizer. The products have good fluorescence properties. The quantum yield of the CdTe nanomaterials was measured to be 0.523 4, and the half-peak width was about 45 nm. By using CdTe nanomaterials as fluorescent probe, based on the enhancement of the fluorescence intensity of CdTe nanomaterials by PA, a simple, rapid and sensitive method for the determination of PA was proposed and validated.Furthermore,the possible mechanism of interaction between CdTe nanomaterials and PA was discussed.Effects of experimental conditions were investigated. The optimal conditions were as follows: buffer: pH 7.4 KH2PO4-Na2HPO4 solution,concentration of PA:100 μg·L-1, reaction time: 15 min, reaction temperature: 20 ℃. Under the optimal conditions, a good linearity was obtained between fluorescence intensity and PA concentration in the range of 8~120 μg·L-1 with a correlation coefficient of 0.996.The obtained linear regression equation was: F /F0=0.001 9c+1.032 1 and the limit of detection was 3.5 μg·L-1.The proposed method was successfully applied in the determination of PA in swine urine samples, at the same time, the method is compared with the traditional liquid chromatography tandem mass spectrometry. The result indicated that the combination of CdTe nanomaterials and PA produced a nice labelling effect, and this method is fast, feasible and effective..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1402 (2020)
Pressure Correction for Calibration-Free Measurement of Wavelength Modulation Spectroscopy in Atmospheric Environment
LI Jin-yi, FAN Hong-qing, TIAN Xin-li, LI Hong-lian, WU Zhi-chao, and SONG Li-mei
Tunable diode laser absorption spectroscopy (TDLAS) has been widely used for trace gas detection due to high sensitivity and selectivity. However, measurement results of the optical gas sensors are constantly affected by the pressure of a target gas, especially in atmospheric environment. Most of the existing methods nTunable diode laser absorption spectroscopy (TDLAS) has been widely used for trace gas detection due to high sensitivity and selectivity. However, measurement results of the optical gas sensors are constantly affected by the pressure of a target gas, especially in atmospheric environment. Most of the existing methods need to install pressure sensors on the spot to correct the measurement results. In this paper, a simple method was proposed for modification of the measured gas concentration without pressure sensor required. A gas absorption line with collision broadening dominant was selected, and wavelength modulation spectroscopy with the first-harmonic (WMS-1f) and the second-harmonic (WMS-2f) detection were performed simultaneously. The analytic expressions characterized by line broadening were established by the spacing between peak and valley of WMS-1f signal and the distance between two zero crossings of WMS-2f signal, respectively. The effect of pressure fluctuation on the measured gas concentration could be corrected by the WMS-1f or 2f signal, due to the relationship between line broadening and gas pressure. Carbon dioxide gas with concentration of 1 980 mg·m-3 was used to verify our method. The CO2 absorption located at 4 989.97 cm-1 was selected for concentration measurement with variable pressures and different modulation depths near atmospheric pressure. The influence of pressure variation on harmonic signals of carbon dioxide absorption spectrum was analyzed experimentally. The gas pressures were inverted by using the WMS-1f peak-valley spacing and the WMS-2f zero-crossing spacing respectively. Compared with the pressure data measured by gas pressure sensor, the pressure deviation was less than 1%. Therefore, the correctness of calculating pressure by analytic expression of harmonic spacing was verified. Finally, the gas concentration corrected by pressure compensation was carried out by using WMS-2f/1f technology. The results showed that the error of the corrected concentration by measuring harmonic spacing is less than 2% compared with that compensated by high-precision pressure gauge, which is consistent with the pressure uncertainty (less than 2%) derived by harmonic spacing. The feasibility and validity of this method are verified. It can further improve the measurement accuracy of TDLAS technology in gas concentration detection under high pressure fluctuation environment. This method is very simple and feasible without requirement of additional gas pressure sensors, which is especially suitable for high sensitivity and high precision open-path measurement of gas composition in atmospheric environment. Moreover, it can also be used for simultaneous measurement of gas concentration and pressure..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1407 (2020)
Improvements of VIS-NIR Spectroscopy Model in the Prediction of TVB-N Using MIV Wavelength Selection
CHEN Yi-fan, LI Yun-jing, PENG Miao-miao, YANG Chun-yong, HOU Jin, and CHEN Shao-ping
Volatile Basic Nitrogen (TVB-N) is an important physicochemical property for the detection of meat freshness. Using visible/near-infrared (VIS/NIR) spectroscopy to analyze TVB-N content is of great importance quantitatively-. The prediction model is the key factor for detection TVB-N content in visible or near infraredVolatile Basic Nitrogen (TVB-N) is an important physicochemical property for the detection of meat freshness. Using visible/near-infrared (VIS/NIR) spectroscopy to analyze TVB-N content is of great importance quantitatively-. The prediction model is the key factor for detection TVB-N content in visible or near infrared spectroscopy. Thus, an accurate and robust prediction model can improve the quantitative analysis results of TVB-N. Firstly, we collected 51 representative pork samples with different freshness, and determine the effective band from 450 to 900 nm after removing low signal-to-noise ratio band from 200 to 450 nm and from 900 to 1 000 nm. Then we use principal component analysis (PCA) to reduce spectral data in order to construct a back propagation neural network (BPNN) model. On this basis, we use the mean impact value (MIV) method to select characteristic wavelengths which strongly related to the content of Total Volatile Basic Nitrogen (TVB-N) in edible meat, and finally construct a MIV-PCA-BPNN prediction model based on 221 selected wavelengths. Experimental results show that the related coefficient of calibration (RC), the related coefficient of prediction (RP), the root means square error of calibration (RMSEC), the root mean square error of prediction (RMSEP) and the robustness index of the PCA-BPNN model are 0.96, 0.93, 1.47 mg/100 g, 1.74 mg/100 g and 1.18, respectively. The PCA-BPNN nonlinear prediction model is better than the classical linear prediction model principal component regression and partial least squares regression prediction model, which proves that TVB-N has strong nonlinear effects. The RC, RP, RMSEC, RMSEP and the robustness index of the MIV-PCA-BPNN model are 0.98, 0.96, 1.12 mg/100 g, 1.21 mg/100 g and 1.08, respectively, it is RMSEC and RMSEP are the smallest, while RC, RP are the largest. Therefore, MIV-PCA-BPNN is the most accurate and robust model in all constructed prediction model. In addition, the characteristic wavelengths selected by the MIV method are concentrated near 7 peaks, which are distributed in the absorption regions of chemical composition in meat. The characteristic wavelengths are consistent with the absorption peaks of H Contained Groups in TVB-N, which provides a theoretical basis for selecting wavelengths by the MIV method. It is found that the MIV wavelength selection is effective to improve the performance of the prediction model, which offers new thought for using the neural network to eliminate irrelevant wavelength variables. The MIV-PCA-BPNN prediction model could be used for the quantitative analysis of TVB-N in meat..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1413 (2020)
The Analysis of Spectral Characteristics of Reflective Thermal Insulation Coatings for Buildings Based on Hyperspectral Data
LI Xiao-fang, YANG Wei, WANG Li-mei, WANG Yan-cang, LI Xiao-peng, and ZHANG Guo-dong
Reflective thermal insulation coatings are a new type of building materials, which have the functions of heat insulation, energy saving and environmental protection, and have been widely used in external structures of buildings. The performance of reflective thermal insulation coatings is mainly determined by their intReflective thermal insulation coatings are a new type of building materials, which have the functions of heat insulation, energy saving and environmental protection, and have been widely used in external structures of buildings. The performance of reflective thermal insulation coatings is mainly determined by their interaction with solar radiation, that is, the reflective and absorptive capacity of reflective thermal insulation coatings can directly reflect the advantages and disadvantages of their thermal insulation and thermal insulation performance. For specific reflective heat insulation coatings, the spectral characteristics of reflective heat insulation coatings mainly depend on their construction thickness parameters. The variation of construction thickness can directly affect the spectral characteristics of reflective heat insulation coatings, and the variation of construction thickness has a great impact on its construction efficiency. Therefore, the variation of spectral characteristics of reflective heat insulation coatings with thickness parameters is explored to determine the best reflective heat insulation coatings. Construction thickness has important practical and theoretical significance for reducing consumption of materials and optimizing construction technology. In order to quantitatively analyze the influence of construction thickness parameters on the spectral characteristics of reflective heat insulating coatings, the spectral data of the thickness of five types of coatings, 0, 0.5, 1.0, 1.5 and 2.0 mm, were used as data sources. The spectral data were processed and analyzed by the methods of de-envelope, absorption peak depth and subtraction, and the effect rules of thickness parameters on reflective and absorption properties of reflective heat insulating coatings were quantitatively analyzed. The results show that: (1) except for ultraviolet-blue light, the reflectivity of coatings to light decreases with the increase of wavelength, that is, coatings have strong reflectivity to short wave band and strong absorption to long wave band, which indicates that coatings have certain thermal insulation and thermal insulation properties; (2) the increase of coatings thickness helps to improve the thermal insulation performance of coatings, but it is helpless. In order to enhance the thermal insulation performance of coatings, the increase of thickness is helpful to enhance the reflectivity of coatings, but the increase of reflectivity of coatings increases first and then decreases, and the change of absorption peak depth increases first and then decreases. When the thickness reaches 1.0 mm, the reflectivity of coatings tends to be saturated; (3) the thickness of coatings has a significant effect on the depth of absorption Valley and has an effect on absorption. Valley (peak) position plays an important role. When the coating thickness reaches 1.0 mm, the absorption Valley (peak) waveform changes..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1420 (2020)
UV-Visible Absorption Spectra and FTIR of Hemoglobin of Healthy People and It Spectroscopic Analysis
QIU Jia-chu, RUAN Ping, YONG Jun-guang, FENG Bo-hua, HUANG Dai-zheng, and SHEN Hong-tao
This study focused on the UV-Visible absorption spectra and the Fourier-infrared spectroscopy of hemoglobin (Hb) in healthy humans and analyzed its spectral characteristics to obtain the UV-Visible absorption spectrum and FTIR of solid Hb with a stable structure in healthy humans. The 21～80-year-old subjects were dividThis study focused on the UV-Visible absorption spectra and the Fourier-infrared spectroscopy of hemoglobin (Hb) in healthy humans and analyzed its spectral characteristics to obtain the UV-Visible absorption spectrum and FTIR of solid Hb with a stable structure in healthy humans. The 21～80-year-old subjects were divided into 4 groupstocollect blood samples. Hemoglobin was purified by G-75 glucan after centrifugation, Structure-stable Hb solids were obtained by the freeze-drying method, and Hb of four groups were determined Ultraviolet-visible absorption spectroscopy and FTIR spectroscopy. QC comparative analysis, full-spectral characterization and secondary structure analysiswere used to obtain the UV and FTIR spectra of healthy human Hb. The analysis showed that the Hb UV-visible absorption spectra and FTIR spectra were the same between the four groups. The matching between the QC and the FTIR spectra was as high as 95%. The UV spectra of all the samples had five characteristic absorption peaks, and the absorption peaks absorbance and wavelength of the position were same. The FTIR spectrum had 13 characteristic absorption peaks, and the absorbance and wave number of the position of the absorption peak between different samples were same; preliminary analysis of Hb ultraviolet absorption spectrum showed that healthy human Hb had the same tertiary structure. The characteristic absorption band of FTIR spectrum Amide Ⅰ band had second derivative spectrum matching degree of up to 99%, and its secondary structure was composed of 11 sub-peaks, and the composition was mainly α-helix. The UV-Vis absorption spectroscopy and FTIR spectroscopy of the structurally stable solid human Hb were obtained. The spectroscopy and structural characteristics of Hb were obtained through preliminary analysis, which was helpful to study related diseases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1425 (2020)
A Study of Adsorption Property of Containing Polyamine Anchoring Group Dispersant onto Oxadiargyl Particles Surface by Using FTIR, XPS and SEM
XU Yong, XU Yan, JIANG Zhe-dong, HUANG Yuan-fang, and WU Xue-min
As an environmentally friendly pesticide formulation, oil-base suspension concentrate has been rapidly developed in recent years. However, due to the relatively weak research on the stability mechanism and the relative lack of precise, quantitative and microscopic characterization methods, the oil-base suspension conceAs an environmentally friendly pesticide formulation, oil-base suspension concentrate has been rapidly developed in recent years. However, due to the relatively weak research on the stability mechanism and the relative lack of precise, quantitative and microscopic characterization methods, the oil-base suspension concentrate products are prone to oil stratification, flocculation, paste and agglomeration during production and storage. As an important surface analysis technology, XPS has the characteristics of high sensitivity, simple sample preparation and small sample destructiveness. It’s often used for qualitative and quantitative analysis of solid surface elements and atomic valence analysis, which is very suitable for dispersant adsorption performance and stability mechanism research. In this research, XPS, FITR and SEM were used to study the adsorption performance of oil phase dispersant containing polyamine anchoring group onto the surface of oxadiargyl particles in oil phase from the microscopic view, which provided a theoretical basis for the application of the dispersant in the oil-based suspension concentrate of pesticide.The results showed: after the dispersant was adsorbed, the Cl, N, O electron peak intensity at the interface of oxadiargyl was weakened, and the C electron peak intensity was enhanced, indicating that the dispersant formed good adsorption on the surface of oxadiargyl. The thickness of the adsorbed layer of the dispersant on the surface of oxadiargyl was calculated to be 6.746 nm using the Cl element as a characteristic element. There was no new absorption peak in the infrared spectrum of oxadiargyl after the adsorption of the oil-base dispersant containing polyamine anchoring group, which indicated that the adsorption between the dispersant and oxadiargyl was physical adsorption with van der Waals force as the main binding force. From the micromorphology of the sample before and after adsorption, it was showed that the surface of the oxadiargyl particles before absorbing the dispersant was rough and had a lamellar structure, while the surface became smooth and the layered structure disappeared after absorbing the dispersant. The difference illustrated that the dispersant containing polyamine anchoring groups formed a coating on the surface of oxadiargyl and improved the physical stability of oxadiargyl oil-base suspension concentrate by providing steric hindrance through the non-polar solvated chains..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1431 (2020)
Study of Temperature Effect on LiCl/(DMSO-H2O) Solution by 2D-IR
WU Xiao-jing, LI Xing-xing, LI Zhi, and CHENG Long-jiu
The study of the solution, especially metal ions in binary solutions, is an important part in the fields of chemical engineering and environment. The traditional analysis would mainly be the use of one-dimensional Infrared spectroscopy or Raman spectroscopy. However, the resolution ratio of the methods is low, and specThe study of the solution, especially metal ions in binary solutions, is an important part in the fields of chemical engineering and environment. The traditional analysis would mainly be the use of one-dimensional Infrared spectroscopy or Raman spectroscopy. However, the resolution ratio of the methods is low, and spectral peaks overlap is serious usually, which will lead to the errors. Two-dimensional infrared spectroscopy (2D-IR) has its advantage, in this article 2D-IR and density functional theory have been combined to analysis of the cluster in solution, and the result could satisfactorily be obtained. Firstly using Fourier transform infrared spectroscopy (FTIR) for DMSO-H2O and Li+/(DMSO-H2O) have been measured in the range of 4 000～400 cm-1 with temperature as external disturbance. One-dimensional infrared spectra of SO double bond could be obtained by normalization of the data. It could be found that the SO of DMSO shifted to red when water was added, and their intensity of SO infrared vibration would increase with the raise of temperature. The intensity of SO double bond would decrease with the addition of Li+, moreover the overlap of peaks was serious, which would influence to distinguish. 2D-IR would be used to analyze, include its type, dynamic change, change order of molecule in SO double bond and the effect of lithium ion on the solution. And the changing rule could be obtained. The cluster structures have been optimized and analyzed by using density functional theory calculation, and the results could prove that it is useful and feasible. Moreover, both the theoretical calculation and experimental have been used in the verification of the clusters in the solution, and these would expand the researchregion. Therefore, when discussed forDMSO-H2O and LiCl/(DMSO-H2O)by using 2D-IR with the temperature change. The results of synchronous 2D-IR have shown that there are four automatic peaks near 1 010, 1 045, 990 and 1 020 cm-1 when temperature is perturbed, which indicates that in SO bond exists methyl vibration, DMSO·H2O, monomer and dimer DMSO molecular clusters. Furthermore, the DMSO·H2O with frequency of 1 010 cm-1 changed earlier has been discovered in asynchronous 2D-IR, and it was speculated that the ［Li(DMSO-H2O)］+ is more sensitive to temperature. By combining density functional theory (DFT) and 2D-IR analysis, the forms of clusters could be ascribed, and the problem of overlap or unobvious peaks in one-dimensional infrared spectroscopy could be solved, and more chemical information would be obtained in a better way..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1436 (2020)
Application of X-Ray in the Study of Cell Wall Structure of Rattan Fibers
WANG You-hong, ZHANG Fei-fei, XUE Xia, JI Bi-chao, LI Dan, and ZHANG Li-ping
Rattan is an important non-timber forest product inferior to timber and bamboo, with high economic value and development prospects. But little is known about the cell structure of rattan, especially the cell wall structure of fiber at present, which seriously limits the research, processing and utilization of rattan. TRattan is an important non-timber forest product inferior to timber and bamboo, with high economic value and development prospects. But little is known about the cell structure of rattan, especially the cell wall structure of fiber at present, which seriously limits the research, processing and utilization of rattan. Therefore, in order to construct the fiber wall structure model and explore the toughness mechanism of rattan, Plectocomia himalayana was chosen as the research material, and X-ray diffraction (XRD) was used to calculate the microfibril angle (MFA), crystallinity and size of microcrystals, among them 0.4T method was used to calculate the MFA. In the MFA test, eight specimens with the size of L(long)×T(thick)×W(wide)=25 mm×0.5 mm×W were selected from one side of the cortex in turn along the diameter direction of the sample, and then placed in the Temperature and Humidity Control Box with the temperature of (20±2)℃ and the relative humidity of 65%±5% for at least one week. When measuring crystallinity and microcrystalline size, each sample was divided into the cortex, middle layer and core. After grounding into powder by Ball Mill, it was put into the Oven and dried to absolute drying at (103±2)℃. The results showed that: the MFA of P. himalayana varied from 22.53° to 49.47° with an average of 36.50°. The MFA was the smallest in the cortex and the largest in the core in radial, which indicated the strength of cortex was better than that of the core. The MFA was 2 m>the tip>the middle>the base in axial, and the regularity between the MFA and the rattan age was not obvious. The cellulose crystallinity varied from 21.40% to 36.45% with an average of 29.99%, and the cellulose crystallinity was the cortex>middle layer>core in radial. Axial upward, with the decrease of rattan age, the crystallinity increased first and then decreased and the maximum value was in the middle and the minimum value was at the base. The microcrystal width of cellulose varied from 5.72 to 6.19 nm with an average of 6.03 nm. The average width of microcrystals at cortex was the smallest and the core was the largest. Like the middle layer and core, the average width of microcrystals of rattan stem decreased first, then reached the minimum in the middle and then rose with the increase of the height. The microcrystal length varied from 13.07 nm to 19.34 nm with an average of 15.59 nm. The length of microcrystals was the cortex>core>middle layer in radial; the length of microcrystals showed a downward-upward-downward trend along with the increase of rattan height in axial, and the microcrystal length at the base was higher than that at the tip, showing a downward trend. The middle part of the stem is better than the base part and the tip part, and the cortex is better than the core..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1442 (2020)
Mechanism Analysis of Formaldehyde Degradation by Hot Braised Slag Modified Activated Carbon Based on XRF and XRD
ZHANG Hao, GAO Qing, HAN Xiang-xiang, RUAN Gao-yang, and LIU Xiu-yu
Activated carbon with developed porous structure and abundant specific surface area was an efficient technical means to remove formaldehyde from indoor air, but it exists the problems of high production cost, unfavorable to the sustainable development of the ecological environment, short service life and easy to cause Activated carbon with developed porous structure and abundant specific surface area was an efficient technical means to remove formaldehyde from indoor air, but it exists the problems of high production cost, unfavorable to the sustainable development of the ecological environment, short service life and easy to cause secondary pollution of indoor environment after failure. Steel slag tailings are the main solid waste in metallurgical industry, with the production of 15%~20% of crude steel. The utilization ratio is quite low and only reaches 10% of steel slag tailings production due to limited technology. Meanwhile, steel slag tailings are disposed in direct stacking and landfill in general since the management system is not perfect, which pollutes land source, underground water source and air quality. In the face of the above problems, the development of low price and superior performance of modified activated carbon has become not only one of the main methods to achieve the high value-added utilization of metallurgical solid waste and the sustainable development of resources, but also one of the main methods to achieve the greatly reduce the production cost of modified activated carbon and improve economic benefits. In this paper, with superfine powder of hot braised slag as the research object, chemical composition of hot braised slag and mineral composition of hot braised slag were characterized by X-ray fluorescence spectrometer (XRF) and X-ray diffractometer (XRD), respectively. According to the main chemical composition and main mineral composition of hot braised slag, hot braised slag chemical composition modified activated carbon and hot braised slag mineral composition modified activated carbon was prepared. Performance of hot braised slag chemical composition modified activated carbon and hot braised slag minerals composition modified activated carbon were tested by referring to Indoor decorating and refurbishing materials-Limit of formaldehyde emission of wood-based panels and finishing products (GB 18580—2017), in order to the influences of main chemical composition and main mineral composition on formaldehyde degradation performance of modified activated carbon. The results show that the main chemical composition of hot braised slag are CaO, Fe2O3, SiO2, P2O5, MgO, MnO and Al2O3, among Fe2O3 and MnO modified activated carbon can improve the formaldehyde degradation performance. The main mineral composition of hot braised slag are Fe3O4, 3CaO·SiO2, 2CaO·SiO2 and RO phase, among Fe3O4 and RO phase modified activated carbon can improve the formaldehyde degradation performance. The element Fe exists as the chemical composition of Fe2O3 and mineral composition of Fe3O4, RO phase in hot braised slag, the element Mn exists as the chemical composition of MnO and mineral composition of RO phase in hot braised slag, the synergistic effect of Fe element and Mn element can improve the formaldehyde degradation performance of hot braised slag modified activated carbon. Hot braised slag modified activated carbon not only realized the high value-added utilization of metallurgical solid waste, but also put forward the new indoor air formaldehyde management technique of “treating danger by waste”..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1447 (2020)
Research on XRD and FTIR Spectra of Fly Ash in Different Particle Size from Gujiao Power Plant
LIU Yun-xia, ZENG Fan-gui, SUN Bei-lei, and JIA Peng
A large amount of fly ash is produced every year in China, and there are big differences in the disposal and utilization of fly ash with different particle size. In order to explore the differences in the composition and structure of fly ash with different particle size, Gujiao fly ash was selected as the research objeA large amount of fly ash is produced every year in China, and there are big differences in the disposal and utilization of fly ash with different particle size. In order to explore the differences in the composition and structure of fly ash with different particle size, Gujiao fly ash was selected as the research object, and sieved into 8 size fractions. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) was used to characterize the samples. XRD pattern shows that the dominant phase is amorphous glass (61.93%～74.76%), mullite (20.45%～29.59%) and a small amount of quartz (1.23%～5.64%). As the particle size increases, the mullite content decreases, the quartz content increases first and then decreases, and the glass exhibits an overall upward trend. FTIR shows that Si—O (Si, Al) asymmetric stretching vibration is main chemical bond (58.86%～67.39%), which is mainly provided by aluminosilicate in glass, followed by Si—O—(Si) bending vibration (15.28%～21.49%), Si—O—Si symmetric stretching vibration (6.18%～9.67%), and Si—O—(Al) symmetric stretching vibration (0.79%～4.02%). With the increase of particle size, the relative content of Si—O(Si, Al) asymmetric stretching vibration increases, Si—O—(Si) bending vibration decreases, while Si—O—Si symmetric stretching vibration and Si—O—(Al) symmetric stretching vibration does not show an obvious change trend. The relationship between XRD content and FTIR chemical bond content shows as Si—O (Si, Al) asymmetric stretching vibration is the main absorption peak of glass, and the content of this band increase with particle size is consistent with the increase of glass obtained by XRD. For quartz, the content got by XRD quantification in different size fractions are also same with the changing trend of the Si—O—(Si) bending vibration near 464 cm-1 and Si—O—Si asymmetric stretching vibration near 1 090 cm-1. The relative content of the strong absorption peak at 556 cm-1 of mullite (y) obtained by FTIR and the mullite content (x%) obtained by XRD shows a linear relationship as y=0.396x-1.997 with 0.868 for R2..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1452 (2020)
Spectral Analysis of Surface Corrosion Products of Two Embedded Gold or Silver Bronze in Ancient China
XU Lai-wu, WANG Yong, YANG Cheng-da, ZHU Yi-fan, HUANG Qiao, and QIN Ying
Gold or silver inlaid craft is a precious metal inlay decoration technique on the surface of Chinese bronzes in the Bronze Age. At present, the research on this technique is less and less in depth, and it is far out of proportion to its once lofty status. Currently, the process of making gold or silver inlaid bronze inGold or silver inlaid craft is a precious metal inlay decoration technique on the surface of Chinese bronzes in the Bronze Age. At present, the research on this technique is less and less in depth, and it is far out of proportion to its once lofty status. Currently, the process of making gold or silver inlaid bronze includes: first casting a bronze body, then pre-casting or engraving the grooves required for the pattern or inscription on the surface of the bronze, finally embedding the finished filigree and finally smoothing, achieving the decorative effect of prominent patterns and inscriptions. In this paper, XRF and XRD methods were used to analyze the composition and phase of the gold or silver inlaid bronze body, the surface of the gold wire (sheet) and the rust products from the late Warring States Period to the Han Dynasties. Two pieces of gold or silver inlaid bronze body alloy composition Cu is 85.10% and 90.15%, Sn is 10.31% and 7.68%, and also contains 3.84% and 1.86% of Pb, respectively. The alloy composition and proportion are common in ancient Chinese bronze. Composition of gold inlaid on the surface of the bronze cup is 70.38% and 75.28%, while that of Ag is 27.51% and 22.50%, which is equivalent to 17～18K gold. The composition of gold inlaid on the surface of bronze tiger-shaped ornaments is 85.16%, 88.06% and 90.24%, and that of Ag is 13.37%, 10.18% and 8.11%, which is equivalent to 20～22K gold. Common rusts of bronze ware are various oxides, carbonates, sulphides or sulphates containing copper, chlorides containing copper, and contaminants from soil such as quartz, calcium carbonate and iron oxide. In addition to the common rust products in the two gold or silver inlaid bronze rusts analyzed in this paper, minerals such as gerhardtite Cu2(NO3)(OH)3 and CuI, which are rare in ordinary bronze rust, are also found. In addition, the bronze casting simulation experiment found that before the rusting, the color difference between the alloy of the gold or silver inlaid bronze body and the gold inlay was not obvious, and the effect of highlighting the decoration of the precious metal inlay was not achieved. Based on this, combined with special rust products, this paper first put forward the idea of whether metal dyeing technology exists in the ancient gold or silver inlaid craft, hoping to attract the attention of scholars..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1457 (2020)
Application of Portable XRF in Core Geochemical Characteristics of Qujia Gold Deposit in Jiaodong Area
GUO Jin-ke, LU Ji-long, YIN Ye-chang, ZHAO Yu-yan, TANG Xiao-dan, FAN Yu-chao, and LIU Yang
Qujia Gold Deposit is located in the Zhaoyuan-Laizhou gold metallogenic belt in the Jiaodong area and is a new achievement in deep geological prospecting. Research samples are not easy to obtain, so portable XRF analyzer is used for analysis, Portable XRF analyzer has three features, it is small in size so easy to carrQujia Gold Deposit is located in the Zhaoyuan-Laizhou gold metallogenic belt in the Jiaodong area and is a new achievement in deep geological prospecting. Research samples are not easy to obtain, so portable XRF analyzer is used for analysis, Portable XRF analyzer has three features, it is small in size so easy to carry, the analysis speed is fast and does not need to destroy the sample, so the analysis result can be quickly obtained without losing the core sample. The study can be divided into the following three aspects, using the rock samples of Jidong area with similar lithology and accurate chemical analysis data to determine the test curve and establish a mathematical model, and then using the portable XRF analyzer to test the core samples of Qujia Gold Deposit, after calibration and replenishment, a batch of test data is obtained. Some samples are selected for pulverization treatment and tested by an X-ray fluorescence analyzer, and the test results of the portable XRF analyzer and the X-ray fluorescence analyzer are compared. Then using the data to analyze the geochemical characteristics of Qujia Gold Deposit, and the core element composition, element vertical distribution characteristics and element association of Qujia Gold Deposit were obtained. The results show that the portable XRF analyzer has accurate and reliable test results for rock samples, the test error is within the allowable range, the accuracy is less than that of the traditional analytical test technology, but it is completely problem-free to apply qualitative analysis and semi-quantitative analysis to the field. The portable XRF analyzer test data corrected and supplemented by the mathematical model fits well with the test data of the X-ray fluorescence analyzer, the factors affecting the accuracy of the portable XRF analyzer for testing the rock sample are mainly the uneven distribution of the rock sample component, the smaller the level, the more uniform the composition, the smaller the test error. When testing, where the composition is more uniform should be selected, or observe the rock samples before the test, assign the test points according to the proportion of the components, and try to take the average as many times as possible. Using the test data to carry out the geochemical study of Qujia Gold Deposit, the analysis results are in good agreement with the known geological conditions, and the reliability of the portable XRF analyzer test data is confirmed from another angle. The core samples have a higher content of Si and Al, and from the surrounding rock to the fracture zone. The K, Ca, S and other microelements and Cu, Pb, Zn and other indicator elements of gold are all enriched. The results of the study generally indicate that the portable XRF analyzer has a good application effect in Qujia Gold Deposit and can be promoted..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1461 (2020)
Analysis of High Content Water-Soluble Salt Cation in Saline-Alkali Soil by X-Ray Fluorescence Spectrometry
ZHAO Yu-yan, ZHANG Ze-yu, TANG Xiao-dan, ZANG Li-bin, LIU Xu-yang, and LU Ji-long
Saline-alkali soil is widely distributed in cultivated land in China, which seriously restricts the development of modern agriculture and rural construction. The mass fraction of soluble salts (Ca2+, K+, Na+ and Mg2+) in the surface layer of saline soil can reach more than 0.1%~0.2%. The excessive concentration of ionsSaline-alkali soil is widely distributed in cultivated land in China, which seriously restricts the development of modern agriculture and rural construction. The mass fraction of soluble salts (Ca2+, K+, Na+ and Mg2+) in the surface layer of saline soil can reach more than 0.1%~0.2%. The excessive concentration of ions in this soil can hinder the absorption of other ions and nutrients by plants and harm the growth of crops through osmosis, stress or ion poisoning. Therefore, saline-alkali land improvement is an important direction of modern agricultural research. Accurate and rapid measurement of water-soluble cationic Ca2+, K+, Na+ and Mg2+ in saline-alkali soil is one of the important foundations and key technical problems for soil improvement. The traditional analytical procedure is oscillating the saline-alkali soil in water for several hours and then taking the supernatant solution for direct determination by atomic absorption spectrometry. As the detection limit of the atomic absorption spectrophotometer is far lower than that of the sample to be tested, multiple dilutions are required in the test process, which increases the systematic error of the test and reduces the credibility of the experimental results. Therefore, in this paper the X-ray fluorescence spectrometer was used to determine the Ca, K, Na and Mg content of original saline-alkali soil sample and residual sample after a certain oscillation time, and then the difference was calculated to obtain the soluble Ca2+, K+, Na+ and Mg2+ content. The test results were compared with those determined by atomic absorption spectrometry. The pH, electrical conductivity and the content change characteristics of the main anions Cl-, SO2-4, HCO-3 and CO2-3 in saline-alkali soil were obtained to confirm the method. The results show that by the X-ray fluorescence spectrometry the soluble Ca2+, K+, Na+ and Mg2+ ion contents do not change much after respectively oscillation for 1 ~ 6 hours. Almost all soluble cations dissolve after oscillation for 1 hour. The measured results of X-ray fluorescence spectrometry are basically consistent with those of atomic absorption spectrometry. In addition, the reliability of X-ray fluorescence spectrometry can also be verified by the mutations in pH and conductivity of the sample after oscillation for 1 hour, and the content changes of main anions obtained by ion chromatography and double neutralization indicator method. The X-ray fluorescence spectrometry method for indirect analysis of high content water-soluble salt cations in saline-alkali soil has the advantages of simple operation, safety, reliability and high accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1467 (2020)
Characterization of Burmese Amber with Three-Dimensional Fluorescence
BAI Ying, ZHENG Xiao-hua, and YIN Zuo-wei
As a kind of organic gemstone, amber generally has a fluorescence phenomenon. In this paper, the three-dimensional fluorescence spectra were adopted to explore the spectral characteristics of Burmese amber, which served as the object of study. The results showed that for Burmese golden amber and brown amber, which emitAs a kind of organic gemstone, amber generally has a fluorescence phenomenon. In this paper, the three-dimensional fluorescence spectra were adopted to explore the spectral characteristics of Burmese amber, which served as the object of study. The results showed that for Burmese golden amber and brown amber, which emit glaringly bluish-white fluorescence under long-wave ultraviolet radiation, there was a fluorescence peak in the three-dimensional fluorescence spectra, the scope of the peak was about λex350～400 nm/λex400～450 nm, and the main fluorescence peakwas positioned at λex360 nm/λem425 nm, with high fluorescence intensity. For the Burmese blood amber, which glows in earthy yellowish fluorescence under long-wave ultraviolet, its fluorescence peaks were located at about λex420～520 nm/λem500～580 nm, and the fluorescence peaks were scattered in multiple small peaks, with weak fluorescence intensity. Heating the golden amber and brown amber samples under oxidizing conditions produced baked “blood amber”, and it was found by comparing its three-dimensional fluorescence spectra before and after baking that fluorescence peaks of the baked “blood amber”, compared with those before baking, were red-shifted, from λex480～530 nm/λem520～570 nm, with extremely weak fluorescence intensity, which was consistent with the fluorescence characteristics of the natural blood amber. The infrared absorption spectrum demonstrated that oxidation caused the concentration of oxygen-containing groups such as carbonyl CO in the molecular structure of blood amber and baked blood amber to increase. As a strong chromophore group, Carbonyl CO made amber in a red appearance with its increased concentration and absorption intensity. Meanwhile, as an electron with drawing substituent, Carbonyl CO replaced the H atom in the molecular structure and linked with the impurity atom with no bonding, producing n→π*1 transition, making the fluorescence intensity of amber weakened, and even quenched, as well as facilitating the fluorescence peaks to shiftin the long wavelength direction. The Three-dimensional fluorescence spectra can present the fluorescence phenomena of Burmese amber in a fast and effective manner, and provides a new analysis tool for the study of amber’s fluorescence characteristics and molecular structure..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1473 (2020)
Determination of Malachite Green Residue in Aquatic Products Based on Three-Dimensional Fluorescence Spectrum
LI Ning-chi, REN Nuo-yu, LIU Chun-yu, YAO Zhi-hai, and CAI Hong-xing
As a chemical agent, malachite green is used as a fungicide in aquatic products because of its good bactericidal properties, low price and a small amount are imperceptible. However, because its metabolite in the body——the recessive malachite green has stability and highly toxic chemical properties. Malachite green has As a chemical agent, malachite green is used as a fungicide in aquatic products because of its good bactericidal properties, low price and a small amount are imperceptible. However, because its metabolite in the body——the recessive malachite green has stability and highly toxic chemical properties. Malachite green has been classified as a banned drug in China. This experiment discusses how to use three-dimensional fluorescence spectroscopy to detect recessive malachite green in aquatic products, and use three-dimensional fluorescence spectroscopy to explore the three-dimensional characteristics of recessive malachite green, and further analyze the relationship between fluorescence intensity and pH change. Finally, fluorescence spectroscopy is carried out for fish samples to discuss the feasibility of three-dimensional fluorescence spectroscopy. The accumulation data and foundation of recessive malachite green in aquatic products are detected by three-dimensional fluorescence spectrometry.The experimental results show thatthe highest peak of the recessive malachite green ethanol solution was obtained at the excitation wavelength of 324 nm/the emission wavelength of 355 nm. The highest peak of recessive malachite green methanol solution was obtained at the excitation wavelength of 320 nm/the emission wavelength of 355 nm. The experimental results show that the fluorescence peak strength is strongest in the pH 7.0 environment. According to the experience of fish sample, we can find that the relationship between the concentration of recessive malachite green and the fluorescence intensity showed a good linear relationship. The recovery rate was 96.65%, which proved that the experimental results have good stability. Therefore, the recessive malachite green in aquatic products can be accurately and quickly detected by three-dimensional fluorescence spectroscopy technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1478 (2020)
Temperature Correction of NIR Reflectance Spectrum of Noninvasive Blood Glucose Measurement Based on EPO
GE Qing, HAN Tong-shuai, LIU Rong, LI Chen-xi, and XU Ke-xin
One of the main challenges in the noninvasive sensing of blood glucose by near-infrared (NIR) spectroscopy is that human temperature changes interfere with the measurement spectrum. In this paper, a spectral pretreatment method based on external parameter orthogonalization (EPO) is proposed to eliminate the spectral vaOne of the main challenges in the noninvasive sensing of blood glucose by near-infrared (NIR) spectroscopy is that human temperature changes interfere with the measurement spectrum. In this paper, a spectral pretreatment method based on external parameter orthogonalization (EPO) is proposed to eliminate the spectral variations from temperature interferences caused by the temperature changes at the measured position. This method only needs to collect the diffuse spectrum when the body temperature changes in advance, using whichwe can obtain the filtering matrix to eliminate the temperature interference.This matrix could be used to calibrate the spectrums at different body temperatures to the reference level. This method establishes a model for external disturbance variables separately in advance and separates it fromthe model between glucose concentrations and the diffuse reflectance. The principle of EPO indicated that spectral space is composed of interference signal space and useful signal spacethat are orthogonal to each other. In other words, the temperature response and the glucose concentration response in the spectral is orthogonal to each other. However, in the actual situation, the instrument system drift, common-mode disturbance such as human body sweating often leads to useful signal and interference signal accidentally correlational that does harmto the effectiveness of EPO.Therefore, we first use the differential correction method based on the spectra from the reference position and measuring position on the original spectrum. It has been proved that the differential correction method can eliminate the common-mode interference brought by the instrument system. In addition, the temperature response part and the concentration response part of the obtained absorbance spectrum are orthogonal to each other. In this paper, the spectral data were obtained by Monte Carlo simulation of human three-layer skin model, and the parameters of the simulated samples were set according to the actual human experiment. The EPO method was used tocalibrate temperature interference in spectra after the differential correction method, and then a partial least squares regression (PLSR) model was established based on the corrected spectral data. Compared with the spectral modeling results before calibration, the root means square error of calibration (RMSEC) was reduced; the correlation coefficient was improved, and the number of principal components was reduced, which indicated the effectiveness of the temperature correction method-EPO..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1483 (2020)
Effect of Zinc on the Growth and Element Content of Lactobacillus Acidophilus
ZHAO Qian-qian, YAN Lai-lai, XIE Qing, LIU Ya-qiong, YANG Si-yu, GUO Chen, and WANG Jing-yu
To investigate the effects of zinc concentration on the growth of Lactobacillus acidophilus and other elements in the bacteria by inductively coupled plasma mass spectrometry (ICP-MS). The potential mechanism of growth and elemental absorption of Lactobacillus acidophilusafterzinc interventionwas investigatedon the re-To investigate the effects of zinc concentration on the growth of Lactobacillus acidophilus and other elements in the bacteria by inductively coupled plasma mass spectrometry (ICP-MS). The potential mechanism of growth and elemental absorption of Lactobacillus acidophilusafterzinc interventionwas investigatedon the re-equilibrium of inorganic elements in the cells. Lactobacillus acidophilus was used as the experimental bacterial strain, and elemental zinc was used as the experimental element to observe the change of growth rate of Lactobacillus acidophilus caused by the change of zinc concentration in the culture solution. A total of 7 zinc concentration groups were set up, and each group of 6 parallel samples had a zinc concentration ranging from 0 to 1 200 ng·mL-1. The concentration interval of each group was 200 ng·mL-1, and the 0 ng·mL-1 group was the control group. Determination of 43 elements such as zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) in culture medium and Lactobacillus acidophilus by inductively coupled plasma mass spectrometry (ICP-MS); The photometer measures the OD value of Lactobacillus acidophilus and monitors its growth rate. Statistical analysis was performed on the obtained experimental data using SPSS 20.0 (Statistical Package for the Social Science 20.0) statistical software. The change of Zn concentration in the culture solution caused the stimulation effect of Lactobacillus acidophilus growth. The stimulating effect was most obvious when the concentration of Zn was 600 ng·mL-1. At the same time, the concentration of inorganic elements in the bacteria changed. The bacteria included Se and Fe in the bacteria. The content of some beneficial elements in the interior increases with the increase of bacterial growth rate, and the content of harmful elements such as Cd decreases. Correlation analysis showed that the content of 11 elements in Se, U, Fe, Al, Ti, Sb, Ba, Mn, Co, Zn, Sr (arranged from high to low according to the overall correlation coefficient of 2～10 hours) There is a good correlation between OD values, in which U, Al, Ti and Sb are negatively correlated, and the other 7 elements are positively correlated; Se, Sr, Al, Mn, Fe, Co, Cd, etc. in Lactobacillus acidophilus The content of 14 elements was significantly correlated with the content of zinc in the cells (p<0.05). The change of zinc concentration in the culture solution will stimulate or inhibit the growth rate of Lactobacillus acidophilus. At the same time, it can also up-regulate some beneficial elements and down-regulate the content of some harmful elements; the rebalancing of beneficial and harmful elements in the bacteria Perhaps the potential mechanism by which zinc in the culture fluid changes the growth rate of Lactobacillus acidophilus..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1489 (2020)
Infrared Spectral Study on the Origin Identification of Boletus Tomentipes Based on the Random Forest Algorithm and Data Fusion Strategy
HU Yi-ran, LI Jie-qing, LIU Hong-gao, FAN Mao-pan, and WANG Yuan-zhong
Boletus tomentipes Earleas a kind of healthy food is favored by the majority of consumers. The nutrient accumulation of the fruiting body is affected by the growth environment (altitude, climate, etc. ). There is a significant difference in the content of nutrient between different regionsIt is urgent to establish an aBoletus tomentipes Earleas a kind of healthy food is favored by the majority of consumers. The nutrient accumulation of the fruiting body is affected by the growth environment (altitude, climate, etc. ). There is a significant difference in the content of nutrient between different regionsIt is urgent to establish an accurate, rapid and cheap origin identification technology. In this paper, a data fusion strategy combined with random forest algorithm (RF) was used to identify the origin of B. tomentipes, and the effects of various eigenvalue extraction methods on the classification of RF models were compared. Fourier transform near infrared and Fourier transform mid-infrared spectra of 87 samples from 4 producing areas (north subtropics, north temperate zones, south subtropical zones and middle subtropical zones) were scanned to analyze their spectral characteristics. All the sampleswere divided into two thirds of the training set (58) and a third of the validation set (29) by the kennard-stone algorithm. Based on 4 kinds of infrared spectra ( near-infrared average spectra of stipes (N-b), near-infrared average spectra of caps (N-g), mid-infrared average spectra of stipes (M-b), mid-infrared average spectra of caps (M-g)) and three data fusion strategies (low-level fusion strategies, mid-level fusion strategies, high-level fusion strategies) of data, combining with the RF building identification model, the effects of different characteristic value (variable importance in projection, Boruta, latent variables) on the classification results of the model are compared. Among them, the optimal ntree and mtrywere selected according to oob. The classification performance of the model was evaluated with specificity, sensitivity, training set correctness, and validation set accuracy. Finally, the best method to identify the origin of B. tomentipes was found by multiple evaluation indicators. The results showed that (1) near infrared and middle infrared spectra could identify the origin of B. tomentipes. (2) It is not ideal for establish a discriminant model with a single spectrum combined with RF. (3) All three fusion strategies can improve the origin identification effect of B. tomentipes. Theresults of origin identification from good to bad are in order of high-level fusion, mid-level fusion, low-level fusion. By scanning the near infrared and middle infrared spectra of B. tomentipes, a high-level fusion strategy based on characteristic value LV was adopted, and the identification model of B. tomentipes from different regions was established with RF, which has high verification set accuracy (99.6%), high sensitivity (0.969) and high specificity (0.986). As a reliable method, it can identify the geographical origin of B. tomentipes quickly and accurately..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1495 (2020)
Study on the Interaction Between Minocycline and Bovine Serum Albumin by Multi Spectral Method and Molecular Docking Simulation
WANG Xiao-xia, NIE Zhi-hua, MA Li-tong, CUI Jin-long, SAI Hua-zheng, and ZHAO Wen-yuan
Minocycline (MC) is a semisynthetic tetracycline broad-spectrum antibiotic with stronger antibacterial activity, which is absorbed rapidly after oral administration, and the binding rate to serum protein ranges from 76% to 83%. The study of the binding mechanism between Bovine serum albumin (BSA) and MC is helpful to eMinocycline (MC) is a semisynthetic tetracycline broad-spectrum antibiotic with stronger antibacterial activity, which is absorbed rapidly after oral administration, and the binding rate to serum protein ranges from 76% to 83%. The study of the binding mechanism between Bovine serum albumin (BSA) and MC is helpful to explore the interaction mechanism between MC and BSA at the molecular level, to further understand the structure and functional relationship of BSA and MC, and to provide necessary data support for the further study of pharmacological toxicity and efficacy of MC. The interaction between MC and BSA has been investigated by fluorescence spectroscopy, circular dichroism, ultraviolet spectroscopy and molecular docking simulation at different temperature and simulated physiological conditions. The results show that MC quenches the fluorescence of BSA, and the quenching constant decreases with the increase of temperature. This indicates that the quenching mechanism of MC and BSA is static quenching. The fluorescence results were calculated using the Stern-Volmer equation and the static quenching double logarithmic formula, and the results showed that the number of binding sites n between MC and BSA is close to 1. According to Van’t Hoff thermodynamic equation at 298, 303 and 308 K, the thermodynamic parameters were obtained as follows: enthalpy change ΔH=-34.14 kJ·mol-1, entropy change ΔS=32.55 J·(mol·K)-1, Gibbs free energy ΔG=-43.84 kJ·mol-1 (298 K), -43.88 kJ·mol-1 (303 K), -44.17 kJ·mol-1 (308 K), which proved that the main force between MC and BSA is the van der Waals and hydrogen bonding, and the process of its action is the spontaneous and exothermic process. Through the UV-visible absorption spectrum analysis of BSA and MC, the position of the absorption peak of BSA has a significant red shift, indicating that the conformation of BSA has changed. According to Frster’s theory of non-radiative energy transfer, the binding distance r between MC and BSA is 1.873 nm, which indicates that non-radiative energy transfer occurs between MC and BSA. In addition, the experimental results of synchronous fluorescence spectroscopy showed that the conformation of BSA changed when MC interacted with BSA, and the binding site was on tryptophan (Trp) residues. The results also showed that the conformation of BSA changed by three-dimensional fluorescence spectroscopy and circular dichroism, and (Trp) the polarity of the surrounding environment decreased and hydrophobicity increased. Quantitative analysis of secondary structure of circular dichroism before and after the interaction of MC and BSA showed that the content of alpha-helix structure in BSA was 31.75%. After adding MC gradually, the content of α-helix structure changed to 47.10% (cBSA∶cTRO=1∶1) and 54.39% (cBSA∶cTRO=1∶5), indicating that the content of α-helix structure increased, and the structure of BSA was mainly α-helix structure. Molecular docking simulation showed that MC interacts into the site I (subdomain IIA) of BSA, it forms van der Waals interaction between MC and the amino acid residues PHE508, LYS535, HIS534, PHE501, GLN579, VAL546, MET547, LEU528, PHE508 of BSA, hydrogen bonds formed between MC and the amino acid residues LYS524 and LEU531, and super conjugation also formed between MC and the amino acid residues ALA527, VAL575, LEU531, PHE508. These amino acids bind closely with MC molecules, and MC changes the secondary structure of BSA. The data obtained in this experiment are helpful to understand the interaction mechanism between MC and BSA, as well as the effect of MC on BSA conformation during storage and transportation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1503 (2020)
Establishment of Quantitative Model for Six Chemical Compositions in Crassostrea Angulata by Near Infrared Spectroscopy
HUANG Guan-ming, GUO Xiang, QI Jian-fei, NING Yue, WU Qi-sheng, WANG Xiao-qing, ZENG Zhi-nan, and ZHU Li-yan
Crassostrea angulata is the main variety of marine aquaculture in southern China. Due to long-term artificial breeding with no germplasm protection measures, its germplasm resources are declining, which has a negative impact on the oyster consumption market. Therefore, it is urgent to develop breeding of Crassostrea anCrassostrea angulata is the main variety of marine aquaculture in southern China. Due to long-term artificial breeding with no germplasm protection measures, its germplasm resources are declining, which has a negative impact on the oyster consumption market. Therefore, it is urgent to develop breeding of Crassostrea angulata (C. angulata). The selection for C. angulata with good nutrition and good flesh quality requires a large number of samples in the nutrient analysis. Traditional laboratory chemical method is time-consuming and costly, so we are looking for an efficient method for determining the chemical content of C. angulata. The spectroscopic scan was carried out using 105 frozen-dried and grinded C. angulata samples (removed the adductor muscle) from six regions with the Fouriernear-infrared spectrometer (Thermo Fisher, USA) in this study. By comparing the spectroscopic scan data to the chemical values, the accuracy of the content predictions of protein, glycogen, taurine, zinc, selenium and calcium in C. angulata obtained by near-infrared spectroscopy (NIRS) was studied. Using TQ Analyst (Thermo Fisher, USA) software, and selecting partial least squares (PLS), spectral preprocessing method like multiplication scattering correction (MSC), 1st derivative, and Norris derivative filter, the near-infrared models of the six components were established. And 1/3 of the total samples were selected as validation samples. The models were validated by external and cross validation. The correlation coefficients of calibration (RC) of the six models of protein, glycogen, taurine, zinc, selenium and calcium were 0.985 3, 0.965 1, 0.950 4, 0.955 4, 0.920 0 and 0.925 2, respectively. The correlation coefficients of prediction (RP) were 0.985 1, 0.963 6, 0.944 1, 0.946 1, 0.919 0 and 0.924 1, respectively. The correlation coefficients of cross validation (RCV) were 0.981 7, 0.946 1, 0.900 5, 0.897 5, 0.875 3 and 0.829 2, respectively. The results showed that the predicted values of the models had a high correlation with the chemical values, which indicated the NIRS could accurately predict the contents of protein, glycogen, taurine, zinc, selenium and calcium in C. angulata. The samples in this study had good representativeness. The collection time was long. The production area was wide and the quantity was large. The samples were frozen-dried, which reduced the influence of water on the spectral quality. Thus, the accuracy and stability of the models were improved. Spectroscopic scan and analysis based on NIRS was very efficient with no chemical reagents and low cost. The established quantitative model for 6 chemical compositions in C. angulata by NIRS would have a great significance for large-scale analysis of the nutritional compositions and for the selection of new strains with good flesh quality in C. angulata..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1509 (2020)
Quantitative Estimation of Soil Organic Matter Content Using Three-Dimensional Spectral Index: A Case Study of the Ebinur Lake Basin in Xinjiang
ZHANG Zi-peng, DING Jian-li, WANG Jing-zhe, GE Xiang-yu, and LI Zhen-shan
The spectral characteristics of soil are the external manifestation of physical and chemical properties in soil. Estimating soil organic matter content (SOMC) by visible-near infrared (VIS-NIR) diffuse reflectance spectroscopy could provide an important scientific basis for the rational development and utilization of lThe spectral characteristics of soil are the external manifestation of physical and chemical properties in soil. Estimating soil organic matter content (SOMC) by visible-near infrared (VIS-NIR) diffuse reflectance spectroscopy could provide an important scientific basis for the rational development and utilization of land resources. However, the soil is a mixture of many substances, and its hyperspectral data have overlapping absorption of certain components (such as salt particles and minerals), and there are collinear problems between the bands, which bring great challenges for spectral analysis and modeling. Through the iterative operation, the spectral index method not only fully consider the synergy between the bands, but also has the function of minimizing the influence of irrelevant wavelengths. In addition, the method extends the spectral features from one dimension to multidimensional, and can easily detect and distinguish subtle absorption peak. In this study, 120 soil samples were collected from the Ebinur Lake Basin in Xinjiang, and SOMC and spectra were measured indoors. Hyperspectral data were preprocessed using first derivative (FD) and continuum removal (CR). Based on the existing two-band index, the third band was added, and the three-band spectral index (TBI) of three SOMCs was constructed by using the optimal band algorithm. The rationality of TBI was discussed from the spectral mechanism. Finally, according to the modeling effect of support vector machine (SVM), the accuracy of SOMC estimation by different dimensional spectral parameters was further compared. The research results showed that: (1) Spectral pretreatment technology could weaken the noise information in the reflection spectrum to some extent and highlighted more potential spectral information; (2) Through comparative analysis, the correlation of SOMC increased with the increase of the spectral information dimension, that was, TBI>two-band index>one-dimensional spectral parameters; (3) The newly developed TBI provided better estimation results than the two-band index and one-dimensional spectral parameters in the modeling and verification process of SOMC. The TBI-1 had the best estimation effect and the determination coefficient of the modeling set. (R2C) was 0.88, the decision coefficient (R2V) of the verification set was 0.85, and the relative analysis error (RPD) was 2.43. In summary, this study compared the response and modeling accuracy of different dimensional spectral parameters to SOMC. It was found that the three-band spectral index was an important parameter for evaluating SOMC and had good performance. In addition, the combination of TBI and SVM algorithm could weaken soil noise information, improved the prediction accuracy of SOMC, and had strong application potential in the estimation of other biochemical parameters of soil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1514 (2020)
Quantitative Analysis of Soil Heavy Metals Based on LSSVM
LIN Xiao-mei, HUANG Yu-tao, LIN Jing-jun, TAO Si-yu, and CHE Chang-jin
In order to improve the accuracy of soil quantitative analysis, the partial least squares (PLS) and least squares support vector machine (LSSVM) were combined with laser-induced plasma technology to analyze the Cu elements in the soil. Two characteristic lines of Cu Ⅰ 324.75 nm and Cu Ⅰ 327.40 nm were compared and analIn order to improve the accuracy of soil quantitative analysis, the partial least squares (PLS) and least squares support vector machine (LSSVM) were combined with laser-induced plasma technology to analyze the Cu elements in the soil. Two characteristic lines of Cu Ⅰ 324.75 nm and Cu Ⅰ 327.40 nm were compared and analyzed, and Cu Ⅰ 324.75 nm was selected as the analytical line. Firstly, the experimental parameters were optimized. The relationship between laser energy, acquisition delay time and signal-to-noise ratio were compared. The optimal energy and optimal acquisition delay time were 90 mJ and 1 000 ns, respectively. Then, the characteristic spectra of five different concentrations of samples were collected under the optimal experimental conditions. The calibration model was established by standard internal method, PLS and LSSVM. By comparing the fitting coefficient, root mean square error and average relative error of the three models, the calibration model of the standard internal method had poor performance due to the influence of soil matrix effect and self-absorption effect. And the fitting degree did not meet the experimental requirements. The values of the root mean square error and the average relative error were too large to meet the accuracy and stability requirements of the experiment. The calibration model was calibrated with PLS. Compared with the standard internal method, the accuracy and stability of the calibration model were significantly improved. R2 was increased from 0.870 1 to 0.985 1. The root mean square error of the training set and the root mean square error of the prediction set were reduced to the order of 0.1 Wt%. But the decrease of the average relative error with PLS model can’t meet the experimental requirement. It indicated that PLS could improve the accuracy of the calibration model rather than the stability of the calibration model. The matrix effect and self-absorption effect of soil cannot be reduced. Compared with the former calibration models, the LSSVM calibration model has better accuracy and stability. The R2 increased to 0.997 6. The data points in the model were basically distributed on the fitted curve with good linear correlation. Compared with the standard internal method, the root mean square error of the LSSVM training set decreased from 3.448 8 Wt% to 0.018 7 Wt%. The root mean square error of the prediction set decreased from 1.280 7 Wt% to 0.149 1 Wt%. The average relative error reduced by 6.24 times. Compared with the PLS calibration model, the parameters of the LSSVM calibration model were greatly reduced. The average relative error reduced from 7.455 6% to 2.137%, which can meet the stability requirements. It shows that the LSSVM algorithm has advantages for improving the accuracy and stability of the calibration model. It can reduce the matrix effects and the self-absorption effects of soil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1523 (2020)
Determination of Arsenic, Mercury, Selenium, Antimony and Bismuth in Soil and Sediments by Water Bath Digestion-Atomic Fluorescence Spectrometry
LIN Hai-lan, ZHU Ri-long, YU Lei, CHENG Yong-xia, ZHU Rui-rui, LIU Pei, and REN Zhan-hong
A method for determination of the contents of As, Hg, Se, Sb and Bi in soils and sediments by atomic fluorescence spectrophotometry (AFS) was established by using aqua regia as the dissolved medium. The sample placed in a 50 mL glass colorimetric tube was dissolved with 10 mL aqua regia (1+1), then put the colorimetricA method for determination of the contents of As, Hg, Se, Sb and Bi in soils and sediments by atomic fluorescence spectrophotometry (AFS) was established by using aqua regia as the dissolved medium. The sample placed in a 50 mL glass colorimetric tube was dissolved with 10 mL aqua regia (1+1), then put the colorimetric tube in a boiling water bath and heated it 2 h, and then removed the colorimetric tube to cool, and then fixed with ultra-pure water and shaken to be tested. Compared with the expensive equipment and the low safety (high temperature and high pressure) of microwave digestion, the water bath digestion method has the advantages of simple equipment, easy operation and high repeatability. Considering that the content of mercury, selenium and bismuth in actual samples is relatively low, the sample after water bath digestion can directly be tested did not pretreat with any more acid or other reagent. The reducing agent (KBH4) is another factor that affects sensitivity. Under the same instrumentation conditions, experiments have shown that the fluorescence intensity for As, Se, Sb and Bi increased first and then decreased as the concentration of KBH4 increased, while the fluorescence intensity for Hg increases as the concentration of KBH4 decreases. In this study, when the concentration of KBH4 is 0.1%, it can get good sensitivity to detect Hg. In order to verify the reliability of the method, the effects of different pre-reducing agents to detect Se in soil and sediments were compared. The data showed that the amount of hydrochloric acid used in the digestion was sufficient to reduce Se(Ⅵ) to Se(Ⅳ), and it is not necessary to add hydrochloric acid or thiourea, but it makes the results much lower when the thiourea added into the sample. Under the optimal experimental conditions, the detection limit (LOD) found were 0.008 mg·kg-1 (for As), 0.002 mg·kg-1 (for Hg and Se), 0.005 mg·kg-1 (for Sb) and 0.003 mg·kg-1 (for Bi) (sample quantity 0.500 0 g, sample volume 50 mL), and the limit of quantitation (LOQ) found were 0.032 mg·kg-1 (for As), 0.008 mg·kg-1 (for Hg and Se), 0.020 mg·kg-1 (for Sb) and 0.012 mg·kg-1 (for Bi). The relative error ranges for the determination of As, Hg, Se, Sb and Bi in soil/sediment standard samples were -3.3%~4.5%, -3.9%~15.4%, -20.2%~7.8%, -13.0%~3.4% and 2.2%~7.0%, respectively. The relative standard deviation range for the determination of actual samples was 0.4%~10.3%. The method has the advantages of simplicity of operation, no need for transfer of containers, high accessibility, low detection limits, high precision and accuracy. The method also can satisfy the analysis requirement of environmental monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1528 (2020)
Insight into Efficient Complexation Mechanism of Cd(Ⅱ) to Hyperthermophilic Compost-Derived Humic Acids by Two Dimensional Correlation Analyses
WEN Ping, TANG Jia, CAI Xi-xi, LIU Xiao-ming, YU Zhen, Lü Jian, and ZHOU Shun-gui
Compared with conventional thermophilic composting, hyperthermophilic composting as a novel technology for the treatment of sewage sludge, has the advantages of higher fermentation temperature, faster humification process and better quality of composting products. However, the application effect of hyperthermophilic coCompared with conventional thermophilic composting, hyperthermophilic composting as a novel technology for the treatment of sewage sludge, has the advantages of higher fermentation temperature, faster humification process and better quality of composting products. However, the application effect of hyperthermophilic compost as the conditioner in the remediation of heavy metal contaminated soil remains unclear. In this study, excitation-emission matrix spectra coupled with parallel factor (EEM-PARAFAC) and Fourier transform infrared spectra coupled with two-dimensional correlation spectroscopy (FTIR-2DCOS) analyses were applied to compare the binding performances of Cd(Ⅱ) to hyperthermophilic compost (HTC)-, thermophilic compost (TC)-, sewage sludge (SS)-derived humic acid (HAs). Three components including humic acid (C1, Ex/Em=270, 350/470), humic-like substance (C2, Ex/Em=270, 325/470), and protein-like substance (C3, Ex/Em=2250, 275/330) were identified from HAs by EEM-PARAFAC, The content of three components from HTC, TC and SS were found to be different. Ryan-Weber fluorescence quenching model was used to fit the fluorescence quenching effect of Cd(Ⅱ) binding to HAs as well as C1 and C2 for different samples. The higher complexing capacity and stability constants of the complexation of Cd(Ⅱ) with HAs, C1 and C2 derived from HTC (LogKCd=5.72～5.95, CCCd=0.977～0.990) than TC (LogKCd=5.62～5.67, CCCd=0.807～0.823) and SS (LogKCd=4.79～5.29, CCCd=0.476～0.581) indicated that HTC-derived HAs presented better complexation ability than other HAs, and the C1 and C2 components in HAs could be important for determining the complexation ability of Cd(Ⅱ) with HAs derived from HTC. FTIR-2DCOS was used to figure out the contribution of the response of functional groups to Cd(Ⅱ) binding to the complexation ability of HAs derived from different samples. Compared with SS- and TC-derived HAs, carboxyl was the most sensitive group to Cd(Ⅱ) addition in HTC-derived HAs. Due to the higher humification degree, as well as the faster response of carboxyl to Cd(Ⅱ) binding with HAs, HTC-derived HAs have the greater complexation ability than both TC- and SS-derived HAs. EEM-PARAFAC integrated with FTIR-2DCOS offers a unique insight into understanding the correlation between HAs and functional groups during the Cd(Ⅱ) binding process, and also provides a theoretical basis for the application of HTC as the conditioner in the remediation of Cd(Ⅱ) contaminated soil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1534 (2020)
Spectroscopy and Microbiological Analysis of Soil Infiltration Clogging in Treating Aged Swine Wastewater
Lü Jing-jing, GONG Wei-jing, DOU Yan-yan, DUAN Xue-jun, LIU Hai-fang, ZHANG Lie-yu, XI Bei-dou, YU Shui-li, and HOU Li-an
Three-dimensional fluorescence spectroscopy (3D-EEMs), infrared spectroscopy, ultraviolet-visible spectroscopy and high-throughput sequencing were used to study the spectral characteristics and microbial diversity during the clogging process of soil infiltration treatment of aged swine wastewater. The experiment was caThree-dimensional fluorescence spectroscopy (3D-EEMs), infrared spectroscopy, ultraviolet-visible spectroscopy and high-throughput sequencing were used to study the spectral characteristics and microbial diversity during the clogging process of soil infiltration treatment of aged swine wastewater. The experiment was carried out in a pilot scale soil infiltration system. Before the system was completely blocked, DOM was converted to fulvic acid after treatment. When the system was blocked, the composition of DOM remained basically unchanged, but the original protein-like peaks in the influent had a weak red shift, a trend of transformation, and the relative intensity of fluorescence peaks decreased, indicating that the concentration of DOM decreased. The main components of DOM were carbohydrates, phenols, lipids, organic acids and aromatic organic compounds. The occurrence of clogging was beneficial to the removal of colored DOM concentration, and the macromolecular benzene ring structure in the effluent decreases. When the reactor was blocked, the microbial diversity of the lower soil samples was greater than that of the upper soil samples, and the bacterial community diversity was greater than that of the fungi community. Actinobacteria and Alpha haproteobacteria alpha-proteus were the dominant bacteria, and the dominant fungi were Sordariomycetes and Eurotiomycetes..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1541 (2020)
Simple and Quick Identification of Adulterated Sesame Oil by Wavelet Moments and Three-Dimensional Fluorescence Spectra
PAN Zhao, LI Rui-hang, WU Xi-jun, and CUI Yao-yao
Sesame oil is rich in nutrients. Due to the high market price, adulteration is frequent, which seriously damages the interests of consumers and the healthy development of the market. Therefore, the development of a fast and accurate method for the identification of adulterated sesame oil (ASO) is of great significance Sesame oil is rich in nutrients. Due to the high market price, adulteration is frequent, which seriously damages the interests of consumers and the healthy development of the market. Therefore, the development of a fast and accurate method for the identification of adulterated sesame oil (ASO) is of great significance for protecting consumer rights and the market health. To this end, this paper proposed a method for identifying ASO with wavelet moments (WMs) combined with three dimensional fluorescence spectra (3DFS). This method is simple and rapid, and can effectively identify ASO. In the article, Taking 43 samples (16 sesame oil, 9 kinds of rapeseed adulteration sesame oil, soybean adulteration sesame oil and corn adulteration sesame oil, respectively) as research objects. The main research contents and results are as follows: The 3DFS of the samples were obtained using a FS920 fluorescence spectrometer. Multiresolution signal decomposition (MRSD) was performed on the spectra using db2 wavelets, and then the 3DFS was reconstructed using the first-order discrete approximation coefficients of MRSD. The first two orders of WMs: W0,0, W1,0, W1,1, W0,1, W2,0, W2,1, W2,2, W1,2, W0,2, were separately used as feature to perform hierarchical clustering (HC) on the samples. Next, combined with Dunn’s cluster validity index (DVI), the classification quality and laws of the same-order and different-order WMs were studied, and the optimal WMs for identifying ASO were determined. Results: MRSD can remove noise and reduce the amount of spectral data by 72.4% on the basis of retaining the effective characteristics of the original spectra. To a certain extent, it can overcome the disadvantages of moment methods that large computational complexity and high-order moments are seriously affected by noise. Using one of W2,1, W2,2, W1,2, W0,2 to perform HC as a feature, the ASO can be easily and quickly identified. The same-order WMs (Wp,q) exhibit regularity as the p decreases q increases, and the effective WMs (EWMs) of the same order were determined. The target moments (TMs) W0,q≥2 and the optimal target moment W0,6 which can be used to identify ASO were determined. Simple and efficient identification of ASO can be achieved by computing HC with any determined WMs. This method can be extended to online measurements. The research ideas and conclusions provide a reference for the identification and classification of vegetable oils, and provide a means to protect consumer rights and market health..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1547 (2020)
Discrimination of Maize Seedlings Containing Residual Coating Agent by FTIR Spectroscopy Combined with Principal Component Analysis
LI Dong-yu, SHI You-ming, and LIU Gang
In order to identify the maize seedlings which contain pesticide residues of coating agent, the roots and leaves of maize seedlings were studied by Fourier transform infrared spectroscopy (FTIR) combined with principal component analysis (PCA). The uncoated and coated maize seeds were planted with the same conditions, In order to identify the maize seedlings which contain pesticide residues of coating agent, the roots and leaves of maize seedlings were studied by Fourier transform infrared spectroscopy (FTIR) combined with principal component analysis (PCA). The uncoated and coated maize seeds were planted with the same conditions, and the infrared spectra of roots and leaves of these seedlings were tested for parallel control experiments. At the same time, the infrared spectra of coating agent and cellulose were tested for reference. The infrared spectra of roots and leaves of the seedlings whose seeds were coated by coating agent showed a peak of C—H bending vibration near at 1 384 cm-1, but the C—H bending vibration in the infrared spectra of roots and leaves of seedlings without coatings appeared near at 1 375 cm-1. Referring to the infrared spectra of cellulose and coating agent, it can be determined that 1 384 cm-1 originated from the coating agent. At the infrared spectra of roots, the absorption peaks of pesticide residues at 1 384 cm-1 are particularly evident, which are sharper than that at 1 375 cm-1. With the growth of maize plants, the relative intensity of the characteristic peak at 1 384 cm-1 in roots tend to decrease, which is due to the continuous transport of pesticide residues to the above-ground organs of seedling, resulting in the reduction of pesticide residues in roots. Besides the characteristic peaks at 1 384 cm-1 of pesticide residues, the amide II band also shows obvious shoulder peak at the infrared spectra of seedling leaves whose seeds are coated by the pesticide, and this shoulder peak is not observed in seedling leaves whose seeds are uncoated. The spectral analysis showed that the characteristic absorption peaks of pesticide residues are covered up by the strong absorption peaks of cellulose, and the characteristic absorption peaks of cellulose result in overlapping of spectral information and redundancy of data. Therefore, the PCA was used to mine the characteristic information in the spectra. In the score plot of principal component 1 (PC 1) and principal component 2 (PC 2) of the roots, the samples containing pesticide residues and those without pesticide residues are clustered into two groups respectively, the scatter points of the two types of samples do not overlap, and the correct recognition rate is 100%. Although the leaves containing pesticide residues and those without pesticide residues are also divided into two groups in the score plot of PC 1 and PC 2, a small number of samples are overlapped, and the correct recognition rate is 93%. The results demonstrated the feasibility of utilizing FTIR spectroscopy combined with PCA, as an objective and rapid method for identification of the maize seedlings containing residual coating agent..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1554 (2020)
Application of Two-Dimensional Correlation Spectra in the Identification of Adulterated Rice
LIU Ya-chao, LI Yong-yu, PENG Yan-kun, YAN Shuai, WANG Qi, and HAN Dong-hai
With the improvement of economic level, people have higher and higher requirements on the quality of rice. Due to the large price difference among different rice varieties, many traders seek profits by filling the inferior with the superior, sometimes the adulteration ratio is as high as 30%, which seriously damages thWith the improvement of economic level, people have higher and higher requirements on the quality of rice. Due to the large price difference among different rice varieties, many traders seek profits by filling the inferior with the superior, sometimes the adulteration ratio is as high as 30%, which seriously damages the interests of consumers. Rice as a carbohydrate, which cannot be distinguished from adulterated rice by one-dimensional near-infrared spectroscopy. At present, many kinds researches focus on the establishment of stoichiometric discrimination model based on one-dimensional spectrum. Two-dimensional correlation spectra have the advantages of high resolution, and the attribution of analytical peaks and the effective information hidden in the one-dimensional spectrum of adulterated rice can be further explored. This paper takes Wuchang rice as the research object, selects six kinds of rice which are difficult to be distinguished by the naked eye as the adulterated rice, and prepares 140 rice samples with a different adulterated proportion of 5% to 50% respectively. The mean spectrum of Wuchang rice was taken as the reference spectrum and the mixing ratio as the external disturbance factor, the NIR spectra of adulterated and Wuchang rice were calculated with the reference spectrum. By analyzing the characteristics of Two-dimensional correlated synchronous spectra of rice with different mixing ratios, it was found that the cross peak intensity of auto-correlation spectra at 1 420 and 1 920 nm and synchronous spectra at (1 420,1 920) and (1 920, 1 420) nm increased with the increase of adulteration ratio, and the 1 920 nm automatic peak has the most significant response to the adulteration ratio. By tracing the generation mechanism of two automatic peaks at 1 420 and 1 920 nm of the autocorrelation spectrum and analyzing the attribution of corresponding functional groups, it was found that the response degree of amylose in rice to the adulteration ratio was higher than that of protein and other carbohydrates. The maximum value of the automatic peak at 1 420 and 1 920 nm and the maximum value of the cross peak at (1 920,1 420) nm in the Wuchang rice synchronous spectrum were used as the discriminant threshold to discriminate 140 rice samples. The results showed that the best discriminant accuracy was 93.3% based on the 1920nm automatic peak value, and the discriminant accuracy was 100% for the adulterated rice samples with the adulterated ratio of 20% or more, As the adulterated ratio to reduce the discriminant accuracy also gradually decline, with 15%, 10%, 5% sample discriminant accuracy were 91.7%, 66% and 75% respectively. To sum up, the blending ratio as the external interference factor and the characteristics of the two-dimensional synchronous spectrum of rice with different adulteration ratios were analyzed, the adulterated rice can be distinguished simply and effectively by the difference of characteristic peak value, compared with previous NIR discriminant models, it is not necessary to prepare a large number of samples to train the model, which provides a new idea for the rapid identification of adulterated rice..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1559 (2020)
The Study on Quickly Determining DON Level in Wheat Flour by Trend Parameter of Spectra
WU Wei, ZU Guang-peng, CHEN Gui-yun, XU Jian-hong, and CHEN Kun-jie
Deoxynivalenol (DON) is a mycotoxin that often occurs in cereals and their derivatives. It is harmful to the life and health of human and livestock. It is urgent to develop a detection method, which can rapidly, accurately and economically detect DON without environmental hazard. This study defined a Trend Parameter (TDeoxynivalenol (DON) is a mycotoxin that often occurs in cereals and their derivatives. It is harmful to the life and health of human and livestock. It is urgent to develop a detection method, which can rapidly, accurately and economically detect DON without environmental hazard. This study defined a Trend Parameter (TP) of the visible-near-infrared (VIS-NIR) spectra. The TP was used to determine the characteristic bands which were most relevant to the DON concentration. In this paper, the rows of spectral matrix of the samples in calibration set were arranged in the order of gradual increase in DON concentration. Each column (each band) of the matrix corresponded to a TP value. Under a certain band, the stronger the increasing trend of the absorbances of all samples in the column direction is (ie, the larger the TP value), the stronger the correlation between the absorbance and the DON concentration in this band is, and this band can be used as a characteristic band for evaluating the DON concentration. The study found that the local maximum of TP appeared at 666, 1 238, and 1 660 nm. The quadratic discriminant analysis (QDA) was performed by the spectra of the three characteristic bands. The wheat flour can be divided into three grades: mild (0
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1565 (2020)
Quantitative Determination of the Number of Moldy Wheat Colonies Based on the Nanoscaled Colorimetric Sensor-Visible/Near Infrared
KANG Wen-cui, LIN Hao, ZUO Min, WANG Zhuo, DUAN Ya-xian, CHEN Quan-sheng, and LIN Jin-jin
This paper innovatively proposes a new method for detecting mold-infected wheat by visible/near-infrared spectroscopy, and it was employed with a nanoscale colorimetric sensor as an intermediate medium to detect volatile organic compounds (VOCs). The mold-infected wheatwas stored under constant temperature and humidityThis paper innovatively proposes a new method for detecting mold-infected wheat by visible/near-infrared spectroscopy, and it was employed with a nanoscale colorimetric sensor as an intermediate medium to detect volatile organic compounds (VOCs). The mold-infected wheatwas stored under constant temperature and humidity conditions for different time duration to prepare experimental samples. The wheat after mold infection had different characteristic volatile gases, and visible/near-infrared spectroscopy was used to collect the spectrum information before and after the combination of volatile gas and nanosized colorimetric sensor respectively. The multi-variable analysis model was combined to predict the number of mold colonies of wheat. The Aspergillus glaucus and Aspergillus candidus were inoculated into sterile wheat to cultivate, and wheat samples were prepared by storing for 0～9 days. According to the pre-experimental study, colorimetric material 8-(4-nitrophenyl)-4,4-difluorobora-dipyrromemethane (NO2BDP) and 8-(4-nitrophenyl)-4,4-difluoro-6-bromoborodipyrrolethane (NO2BrBDP) sensitive to volatile gases of wheat was used. A nanosized sensor array was fabricated to detect these characteristic volatile gases. The experiment used the soap-free emulsification method to synthesize a nanoscaled microsphere polystyrene-acrylic acid, and it was used to couple NO2BDP and NO2BrBDP dyes for producing nanoscale colorimetric sensors with high specific sensitivity. The spectral information of each wheat sample with different mold amount was collected by visible/near-infrared technology, as well as pre-processed by multivariate analysis. The number of colonies were determined by plate colony counting method, and quantitative prediction models were respectively established for the total number of Aspergillus glaucus and Aspergillus candidus colonies.The experimental results showed that the Si-UVE-PLS model for predicting the total number of Aspergillus glaucus colonies is the best in the characteristic spectral collected by two nanosized sensor.And the square root of the cross-validation of the prediction set was 0.444 4 lgcfu; the correlation coefficient between the measured value and the predicted value was 0.981 1. The optimal model for detecting the total number of Aspergillus candidus) colonies was the Si-GA-PLS model with the spectral data collected by the sensor consisting of two nonnanosized and two nanosized sensors. The RMSECV of the prediction set was 0.554 5 lgcfu, and the Rp in the predicted set was 0.977 2. The research results showed that the combination of visible/near-infrared spectroscopy and nanoscaled sensor technology could well complete the quantitative detection of volatile gases and realize the quality monitoring of mildew wheat..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1569 (2020)
Study on Response of Water and Nitrogen Stresses in Soybean Based on Hyperspectral Analysis
LIU Shuang, YU Hai-ye, CHEN Mei-chen, PIAO Zhao-jia, YU Tong, LI Fa-qin-wei, and SUI Yuan-yuan
Rapid and non-destructive testing of soybean stress environment are critical to improving soybean quality and yield. In recent years, the detection of plant stress by hyperspectral technology has been widely used, but there are few reports on the application of water and nitrogen stress in soybean. Four kinds of water Rapid and non-destructive testing of soybean stress environment are critical to improving soybean quality and yield. In recent years, the detection of plant stress by hyperspectral technology has been widely used, but there are few reports on the application of water and nitrogen stress in soybean. Four kinds of water and five kinds of nitrogen levels were set in the flowering and pod-forming soybeans for stress experiments in this paper. After the stress, the physiological information data of hyperspectral, chlorophyll content and net photosynthetic rate were obtained, and 15 spectral vegetations indices were calculated by spectral data. The index NDVI, RVI, GNDVI, mNDVI705 and LCI were used to indicate the effects of water and nitrogen stress on soybean. And soybean physiological information was predicted by establishing single leaf chlorophyll content and net photosynthetic rate inversion model. The sensitive region was extracted by correlation analysis, and they were 520～622 and 485～664 nm respectively. Multivariate scatter correction (MSC), standard normal variable transformation (SNV), first derivative (FD), second derivative (SD) and Savitzky-Golay smoothing (S-G) preprocessing are used, while two modeling methods, principal component regression (PCR) and partial least squares (PLS), are selected to combine them into several methods according to a certain relationship. The correlation coefficient is used as a model evaluation index to find a combination of optimal preprocessing and modeling methods. The results showed that the hyperspectral curves of non-stressed and stressed soybeans had the same trend but different spectral reflectance values. The reflectance of unstressed soybean has the lowest value in the 500～700 nm region and the highest value in the 760～900 nm region, and the reflectance in the 500～700 nm region gradually increases with the increase of the degree of water-nitrogen stress. The effects of different water and nitrogen levels on vegetation index were different, but the changes were consistent. The 5 vegetation indexes showed that the unstressed soybean was larger than the stressed soybean, and the vegetation index value decreased with the increase of the degree of water-nitrogen stress. The optimum combination of inversion models is MSC+FD+S-G+PLS and SNV+SD+S-G+PLS. The correlation coefficients of the correction set are 0.960 6 and 0.992 7, and the correlation coefficients of the prediction set are 0.972 0 and 0.970 8, respectively. The results show that the model has high precision, and can accurately predict the physiological information of chlorophyll content and net photosynthetic rate of stressed and unstressed soybean, and provide technical support for detecting physiological information during large-scale planting..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1575 (2020)
Detection of Crop Chlorophyll Content Based on Spectrum Extraction from Coating Imaging Sensor
LONG Yao-wei, SUN Hong, GAO De-hua, ZHENG Zhi-yong, LI Min-zan, and YAN Wei
In order to quickly analyze the growth of the crop in the field, the spectral imaging sensor was used to detect the chlorophyll content of the maize canopy. The images of 47 maize plants were photographed using an IMEC 5×5 imaging unit multispectral camera. The camera was designed based on the coating principle toIn order to quickly analyze the growth of the crop in the field, the spectral imaging sensor was used to detect the chlorophyll content of the maize canopy. The images of 47 maize plants were photographed using an IMEC 5×5 imaging unit multispectral camera. The camera was designed based on the coating principle to obtain spectral images of 25 wavelengths in the range of 673～951 nm. At the same time, the chlorophyll content was measured by SPAD-520 device. There were 2～3 sampling points in each leaf, and they were measured 3 times at each point, so that 251 sample data were collected. The multi-spectral images were processed. Firstly, the gray pixel values of the same band in the imaging unit were extracted based on the principle of the coating spectral imaging sensor. The extraction methods included image splitting and recombination, in which 25 images were extracted from the original image. Secondly, a linear inversion formula between the gray value of multi-spectral images and the gray plate standard reflectance was established. The gray plate standard was made up of 4 gray level standard plates. Thirdly, the image segmentation algorithm was established to reduce the background influence in maize canopy images, in which the OTSU algorithm was used to eliminate the interference of the soil and the Hough circle transform algorithm was used to eliminate the interference of the flowerpot. Lastly, the study used the Mahala Nobis distance algorithm to eliminate abnormal sample data. According to the proportion of 2∶1, the total samples were divided into calibration set (170 samples) and validation set (73 samples) by SPXY (Sample set partitioning based on joint X-Y distance) algorithm. The partial least squares regression (PLSR) model was established to detect the chlorophyll content of the maize canopy. In general, the results of spectral bands reflectance linear calibration fitting model were above 0.99. The corrected data was consistent with the ASD spectral reflectance before calibration. The interference of soil and flowerpot background noise in the multi-spectral images were removed by the image segmentation algorithm. The calibration accuracy of PLSR model was 0.545 1, and the validation accuracy was 0.472 6. And then the chlorophyll content of each pixel in the maize canopy images could be calculated by the PLSR modeling result. As a result, the chlorophyll content distribution could be visually analyzed and indicated the growth status. The study could provide technical and application support for the chlorophyll distribution of field maize plants..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1581 (2020)
Recognition of Pig Eating and Drinking Behavior Based on Visible Spectrum and YOLOv2
Ji Yang-pei, YANG Ying, and LIU Gang
The eating and drinking behavior of pigs is the most direct evidence to evaluate the health degree of pigs. Therefore, it is of great significance to use real-time monitoring of the eating and drinking status of pigs by computer vision technology for improving the welfare of pig breeding. This paper proposes a recognitThe eating and drinking behavior of pigs is the most direct evidence to evaluate the health degree of pigs. Therefore, it is of great significance to use real-time monitoring of the eating and drinking status of pigs by computer vision technology for improving the welfare of pig breeding. This paper proposes a recognition method of pig eating and drinking behavior based on visible spectrum and improved YOLOv2 neural network. The method builds head-neck model on the pig visible spectrum image sequence, making use of improved YOLOv2 neural network to realize target detection in the scene of the real pigsty, then utilizing the output of the position information for preliminary judgment of eating and drinking behavior. Then using traditional image processing methods to make an accurate judgment of pig eating and drinking behavior. First, the head-neck model is constructed in the sequence of pig images, and the unblocked head and neck were used as the detection target. This model can effectively solve the occlusion problem in the pig target detection processing, and can also accurately locate the head of the pig, providing assistance for the subsequent identification of eating and drinking behaviors. Then this paper adopted the international mainstream neural network YOLOv2 as the basic network model for target detection, and improve the activation function to achieve fast and accurate target detection of live pigs. Before network training, the K-means algorithm is used to cluster the target frame of the homemade pig data set. Compared with the initial performance of YOLOv2, the mAP value and the Recall value was improved by 3.94% and 5.3%. In order to increase the robustness of the network-facing input changes or noise, this paper compared the performance of the three activation functions of ReLU, Leaky-ReLU and ELU, and found that the performance of the ELU was significantly different from the former two. Compared with the original YOLOv2 and Faster R-CNN, the target detection model in this paper has a mAP value of 90.24% and a recall value of 84.56%, both of which are better than the latter two. Finally, the pig head-neck position information gets from target detection was used to make the preliminary judgment of eating and drinking behavior. When pigs appeared in the eating and drinking area of the picture, background difference method, morphological calculation and other image processing methods are performed on the picture, and the pig eating and drinking behavior is judged more accurately by combining with the residence time of the drinking area. The experiment shows that: the method used in this paper can be used to judge the eating and drinking behavior with an accuracy of 94.59% and 96.49%, which are better than the results judged by the traditional method directly, and can be applied to assist the management of breeding personnel in the actual breeding process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1588 (2020)
A Fluorescence Detection Method for Melanin Content in Black-Bone Silky Fowl Melanocyte Based on H2O2 Oxidation
CHEN Lu-lu, and TIAN Ying-gang
We established a simple, accurate and highly sensitive fluorescence analysis method for detecting the melanin content of Black-bone Silky Fowl (BSF) melanocytes for the first time. Melanins did not fluoresce but, once they were subjected to oxidative conditions (heating in alkaline hydrogen peroxide solution), they acqWe established a simple, accurate and highly sensitive fluorescence analysis method for detecting the melanin content of Black-bone Silky Fowl (BSF) melanocytes for the first time. Melanins did not fluoresce but, once they were subjected to oxidative conditions (heating in alkaline hydrogen peroxide solution), they acquired strong fluorescence. Melanin content of melanocytes was determined by measuring its relative fluorescence intensity. In this paper, the excitation wavelength and emission wavelength of BSF melanin were determined by fluorescence spectrophotometer with a bandwidth of 5 nm, scanning speed of 2 400 nm·min-1 and scanning pitch of 1 nm. The optimal oxidation conditions of BSF melanin in the range of 10～100 μg·mL-1 were screened by a single factor experiment. The linear range, detection limit, instrument precision and repeatability of the method were analyzed and evaluated. 25, 40 and 80 μg·mL-1 melanin standards were added to samples of A375 cells (melanoma cells without melanin), and the melanin content in the cell samples was determined after that the reaction was carried out under optimal oxidation conditions. Calculate the relative error value of the measured value and the theoretical value for exploring the effect of heterologous proteins and lipids in cells on the quantitative results of melanin; After that 5.00, 7.50 and 10.00 μg melanin standards were added to BSF melanocyte samples, the total melanin content in the cell samples was determined under optimal oxidation conditions and then the spiked recovery was calculated. The results showed that the BSF melanin had an excitation wavelength of 354 nm and an emission wavelength of 453 nm; The optimal oxidation conditions for BSF melanin were as follows: the PH value was 8, oxidation temperature was 55 ℃, hydrogen peroxide concentration ranged from 24% to 26% and oxidation time was 2 h; The concentration of melanin in the range of 10～100 μg·mL-1 showed a good linear relationship with the relative fluorescence intensity. The correlation coefficient was 0.997 4 and the linear regression equation was y=0.014 7x+0.313 8. The detection limit of the method of fluorescence analysis was 0.30 μg·mL-1 and the detection limit of ultraviolet spectrophotometry was 3.68 μg·mL-1. The RSD value of the precision experiment was 1.87%, and the RSD value of the repeat experiment was 4.59%. After adding melanin standards of different quality to A375 cells, the relative errors of measured values and theoretical values were 2.78%, 3.53%, and 0.25%, respectively; After adding different melanin standards to BSF melanocytes, the measured recovery rates were 95.94%, 92.14%, 99.83% and the RSD value was 4.00%. In summary, the method was simple, accurate, stable, and low detection limit. In addition, the measurement result was not interfered by intracellular heteroprotein and lipid. So the method was more suitable for determining the content of melanin in BSF melanocytes..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1595 (2020)
Study on Prediction Model of Malathion Pesticide Concentration Absorption Spectra Based on CARS and K-S
ZHEN Huan-yi, MA Rui-jun, CHEN Yu, SUN Xiao-peng, and MA Chuang-li
In this study, the fast and effective quantitative prediction analysis model was established by using the absorption spectrum data of different concentration gradients of malathion in the ultraviolet/visible wavelength range. In the process of establishing a prediction model, the quality of the calibration set samples In this study, the fast and effective quantitative prediction analysis model was established by using the absorption spectrum data of different concentration gradients of malathion in the ultraviolet/visible wavelength range. In the process of establishing a prediction model, the quality of the calibration set samples and wavelength variables involved in the modeling plays a decisive role in the predictive ability of the quantitative analysis model. Therefore, firstly checked whether there were abnormal samples in the experimental samples, then used the different preprocessing methods for the spectral data in the wavelength range of 200.08 to 750.04 nm and then established corresponding PLS model, Further based on the spectral data of the optimal preprocessing result (mean centering), competitive adaptive weighted algorithm (CARS) and Monte Carlo-uninformative variable elimination method (MC-UVE) were used to select the key wavelength variables respectively and established corresponding PLSprediction model. Model results indicated that CARS algorithm was superior to MC-UVE algorithm in the performance of key variable screening; then 18 wavelength variables (1.137 8% of the original variable number) selected by CARS algorithm combined with the 44 modeled samples (88% of the original sample number) respectively obtained from Kennard-Stone (K-S) algorithm method and Monte Carlo cross-validation method (MCCV) to establish CARS-K-Ss-PLS and CARS-CCVs-PLS quantitative prediction model, which R2p were 0.998 2 and 0.998 9, RMSEP were 0.863 4 and 1.026 2, and RPD were 24.163 5 and 20.330 1, as a result the CARS-K-Ss-PLS model was slightly better CARS-CCVs-PLS model. The experimental results showed that the CARS algorithm could eliminate variables with weak correlation with sample concentration and effectively eliminate irrelevant spectral information. The K-S algorithm can help to select a better modeling sample set. UV-Vis absorption spectrum of malathion pesticides combined with the CARS-K-Ss-PLS model established by the CARS algorithm and K-S algorithm can predict malathion pesticide concentration. This study provides a certain of the important theoretical basis and experimental basis for the rapid detection of organophosphorus pesticide concentration by spectroscopy technology, and has a good application prospect in the field of rapid detection of organophosphorus pesticide..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1601 (2020)
Research on the Shrimp Quality of Different Storage Conditions Based on Raman Spectroscopy and Prediction Model
SUI Ya-nan, ZHANG Lei-lei, LU Shi-yang, YANG De-hong, and ZHU Cheng
About the prawn’s freshness characteristics of quality deterioration, the research takes color (L*, a*, b*), volatile base nitrogen(TVB-N), ph, and other quality indexes as the object of the study, and uses Raman nondestructive testing technology to select the spectral information of fresh prawn on the temperature of 4About the prawn’s freshness characteristics of quality deterioration, the research takes color (L*, a*, b*), volatile base nitrogen(TVB-N), ph, and other quality indexes as the object of the study, and uses Raman nondestructive testing technology to select the spectral information of fresh prawn on the temperature of 4 ℃ and under -20 ℃, also makes the quick quantitative test by combining with ridge regression, partial least squares method and forward stepwise regression, establishes the quantitative mode of the quality index. And the spectral data preprocessing includes SG smoothing, background deduction, second order differential and standard normal variable transform, combines 4 types of preprocessing in a certain way and deals with the data by PCA dimension reduction technology, in order to select the best mode. The result shows that, when using ridge regression to establish the quantitative mode of color (a*, b*), under the combined pretreatment mode, the modeling centralization R are 0.983 and 0.973 respectively, RMSE are 0.114 and 0.179 respectively; the forecast concentration R are 0.513 and 0.564 respectively, RMSE are 0.615 and 0.918 respectively, the accuracy of the modeling set is much higher than that of the prediction set, which indicates that there exists over-fitting, and the over-fitting decreases after dimension reduction by PCA, but the prediction effect of prediction sets is not satisfactory; partial least squares method and the ridge regression are about the same on the accuracy of indicator modeling sets, the accuracy of partial least squares method is lower on the prediction sets. After PCA dimension reduction, the related coefficient of partial index modeling sets decrease, the root mean square error increases, and the prediction accuracy decreases. The final result shows that, after 4 types of preprocessing, the mode of forward stepwise regression is the best, the modeling centralization L*, a*, b*, pH, TVB-N index R are 0.904, 0.885, 0.864, 0.934, 0.940 respectively, RMSE are 1.141, 0.280, 0.535, 0.131, 2.345 respectively; the forecast concentration R are 0.863, 0.850, 0.859, 0.900, 0.916 respectively, RMSE are 1.394, 0.406, 0.605, 0.194, 2.734 respectively, the modeling effect is good. Therefore, it is practicable to use the Raman spectroscopy technology, combining with forwarding stepwise regression to quick test the prawn’s L*, a*, b*, pH and volatile base nitrogen content, which provide meaningful guidance for the application of Raman technology in prawn quality detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1607 (2020)
The Determination of Potassium Sorbate Concentration Based on ICSO-SVM Combining Three-Dimensional Fluorescence Spectra
WANG Shu-tao, LIU Shi-yu, WANG Zhi-fang, ZHANG Jing-kun, KONG De-ming, and WANG Yu-tian
Potassium sorbate is a typical food preservative in daily life. Excessive consumption of the preservative potassium sorbate shall do harm to people’s health seriously. Using orange juice as background solution, 22 sets of samples of potassium sorbate orange juice solution with potassium sorbate content ranging from 0.0Potassium sorbate is a typical food preservative in daily life. Excessive consumption of the preservative potassium sorbate shall do harm to people’s health seriously. Using orange juice as background solution, 22 sets of samples of potassium sorbate orange juice solution with potassium sorbate content ranging from 0.007 0～0.100 0 g·L-1 were prepared. In this paper, the fluorescence characteristics of potassium sorbate in aqueous solution and in orange juice solution are studied by using FS920 fluorescence spectrometer. Due to the interference of orange juice, the concentration of potassium sorbate no longer satisfies the linear relationship with fluorescence intensity, and the prediction of the concentration of the substance is complicated. In this paper, an improved chicken swarm optimization support vector machine (ICSO-SVM) model is constructed to process the fluorescence spectrum data. Eighteen samples are selected as training set and four samples as prediction set. Under the optimum excitation wavelength λex=375 nm, the fluorescence intensity of each samples in the range of 450～520 nm are taken as input, and the concentrations of potassium sorbate orange juice are taken as output. Firstly, the parameters of the improved chicken swarm algorithm (ICSO) are initialized, then the optimal values of penalty factor C and kernel parameter g of the support vector machine (SVM) are found by training, and the optimal values are input into the ICSO-SVM model. The predicted concentration values of four groups are 0.011 5, 0.026 0, 0.077 0 and 0.092 0 g·L-1, respectively. The mean square error of ICSO-SVM model is 1.01×10-5 g·L-1, and the average recovery is 101.73%. Compared with chicken swarm optimization support vector machine (CSO-SVM), genetic algorithm optimization support vector machine (GA-SVM) and particle swarm optimization support vector machine (PSO-SVM) under the same conditions. The results show that the prediction accuracy of ICSO-SVM model is higher than that of CSO-SVM, GA-SVM and PSO-SVM. Moreover, the improved chicken swarm algorithm is easier to find the global optimal value in the training process and has faster iteration speed. This paper provides a new method for predicting the concentration of substances..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1614 (2020)
The Response of Spectral Characteristics and Leaf Functional Traits of Euonymus Japonicus to Leaf Dustfall
ZHU Ji-you, HE Wei-jun, WANG Hong-qiang, YAO Jiang-ming, QIN Guo-ming, XU Cheng-yang, and HUANG Tao
Leaves of urban green plants have an important role in retaining and fixing atmospheric dust particles. Euonymus japonicus is the evergreen broad-leaved shrub species with the largest acreage in Beijing, which play a major role in the retention of dust particles in winter. An urban ecosystem is one of the most frequentLeaves of urban green plants have an important role in retaining and fixing atmospheric dust particles. Euonymus japonicus is the evergreen broad-leaved shrub species with the largest acreage in Beijing, which play a major role in the retention of dust particles in winter. An urban ecosystem is one of the most frequent and intense areas of human activity. Its environment is extremely complex. In the past studies, the random and scattered urban environment was mainly used as sampling points. However, plant functional traits have a certain ecological trade-off strategy in internal or phenotypic structures due to their sensitive response and plasticity to environmental changes during long-term growth, reproduction and evolution. In the actual research process of the relationship between leaf dust retention and spectral characteristics, the important influences of water, soil, light and conservation mode of plants in different habitats were often neglected, which could not clearly explain the problem of the spectral response. Based on the law of dust particle diffusion, this study divides the high, medium and low dust concentration environment according to plant position and road surface distance, which can better avoid interference caused by light, moisture, nutrients and soil, etc. Combining the characteristics of plant functional traits, the trade-off strategy of leaf surface spectrum and leaf functional traits of Euonymus japonicus under different dust concentrations was investigated, and the relationship between its hyperspectral parameters and leaf surface dustfall was analyzed, and then a prediction model of dust retention was established. It provides an important reference for the use of hyperspectral detection of vegetation growth in urban environments. The results showed that: (1) In the environment of dust pollution, Euonymus japonicus generally showed a combination of traits with lower leaf area, lower leaf area, lower chlorophyll content, high dry matter content and high leaf thickness, which reflected the structural construction of plant leaves. The trade-off strategy between investment and return also fully illustrates the poor coercion caused by plants in order to adapt to the habitat characteristics of urban environmental pollution and adjust their own functional traits. (2) From the visible to near-infrared range (350~2 500 nm), there were four distinct reflection peaks and four major absorption valleys. In the 350~1 870 nm intervals, the spectral reflectance was generally negatively correlated with the amount of dustfall on the foliar surface. It can be seen that the spectral reflectance decrease with the number of dustfall increases. However, the variation of leaf dustfall in the 1 870~2 500 nm band was more complicated and had no obvious regularity. (3) The spectra of the 700~1 410 and 1 470~1 830 nm bands were sensitive to the response of foliar dustfall and the “red edge effect” appeared in the 680～780 nm range. A higher reflection platform appeared in the 750~1 350 nm range, which may be due to the strong absorption of the leaf moisture in this band. (4) Red edge slope, blue edge slope, yellow edge slope, and yellow edge position are very sensitive to the interference of foliar dustfall, but the red edge position and blue edge position are not obvious. Combined with the trade-off strategy of leaf functional traits, it is known that due to the long-term dust pollution environment, a special adaptation mechanism is formed. Foliar dust reduction is not sensitive to the influence of red edge position and blue edge position, showing strong Anti-interference ability. The red edge slope and the blue edge slope are negatively correlated with the foliar dustfall response, while the yellow edge slope is positively correlated with the leaf surface dustfall response. At the same time, with the increase of the amount of dust on the leaf surface, the position of the yellow edge has a significant “left shift” phenomenon. (5) In this study, foliar water content index, chlorophyll index, red edge index, normalized index, simple ratio index, and photosynthetic reflectance spectral parameters were used as independent variables, and the leaf dust retention of Euonymus japonicus was used as the dependent variable. We establish a prediction model of foliar dustfall in linear, quadratic polynomial and logarithmic forms, respectively. In all models, the quadratic polynomial prediction model based on the foliar water content index has a higher prediction accuracy for foliar dustfall (y=-1.112 3x2+0.543 9x+0.991 1, R2=0.828 9, RMSE=0.122)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1620 (2020)
Research of Flame Retardant Mechanism for RPUF/EG Composites Based on TG-FTIR and XPS
LIU Xiu-yu, ZHANG Bing, ZHANG Hao, DU Xiao-yan, and TANG Gang
This work aims to research rigid polyurethane foam (RPUF) and rigid polyurethane foam/expanded graphite composites (RPUF/EG). Thermogravimetric analysis-Fourier transform infrared spectrophotometer (TG-FTIR) was applied to investigate generation and change law of gaseous phase products in combustion process. Scanning eThis work aims to research rigid polyurethane foam (RPUF) and rigid polyurethane foam/expanded graphite composites (RPUF/EG). Thermogravimetric analysis-Fourier transform infrared spectrophotometer (TG-FTIR) was applied to investigate generation and change law of gaseous phase products in combustion process. Scanning electron microscope (SEM) and X-ray photoelectron spectrometer (XPS) were used to investigate micro-morphology, elemental composition and bonding state of the char residue, which combined to flame retardant tests to discover flame retardant mechanism of PRUF/EG composites. SEM analysis revealed the existence of a lot of wormlike structure in char residue of RPUF/EG composites. TG-FTIR revealed that RPUF/EG composites presented two stages in decomposition process; the first one corresponded to decomposition of hard segment of polyurethane molecular chain, while the seconded one corresponded to decomposition of soft segment of polyurethane molecular chain. The pyrolysis products of RPUF and RPUF/EG composites included isocyanate compound, amine compound, hydrocarbons, aromatic compounds, CO, CO2 and esters, and RPUF/EG presented higher intensity of decomposition products for hard segment compared with RPUF. XPS revealed that char residue of RPUF contained C of 77.63%, N of 10.30%, O of 12.07%, while char residue of RPUF/EG30 contained C of 82.18%, N of 9.18%, O of 8.35%. Furthermore, peak fitting for bonding state of C element showed that C—C/C—H, C—O/C—N and CO/CN structure in char residue of RPUF were 51.38%, 38.89% and 9.73%, while those in char residue of RPUF/EG30 were 53.99%, 37.62% and 8.39%, indicating EG promote C element in polyurethane molecular chain to form stable graphite carbon structure, which was beneficial to form compact char layer. Peak fitting for bonding state of N element showed that —NH— and N structure in char residue of RPUF were 49.06% and 50.94%, while those in char residue of RPUF/EG30 were 43.96% and 56.04%, indicating EG promote N element in polyurethane molecular chain to form stable aromatic heterocyclic structure, which was also beneficial to form compact char layer. Peak fitting for binding state of O element showed that O, —O— and O2/H2O structure in char residue of RPUF were 19.30%, 16.72% and 63.98%, while those in char residue of PRUF/EG30 were 25.57%, 36.60% and 37.83%, indicating that the significant enhancement of compactness for the char residue of RPUF/EG composites. Based on TG-FTIR, XPS, SEM and flame retardant tests, flame retardant mechanism can be obtained as follows: EG particles expanded to form wormlike structure and released acid gas, which promoted the degradation of hard segment of polyurethane molecular chain. At the same time, EG promoted C and N element in polyurethane molecular chain to form compact char layer, which combined with wormlike structure to cover on the surface of combustion area, significantly inhibited mass and heat transmission, thus achieving the purpose of flame retardancy. The above researches provided experimental and theoretical basis for discovering flame retardant mechanism of EG and expanding further application in relative fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1626 (2020)
Visible and Near Infrared Spectral Analysis of the Lubricating Oil Dynamic Viscosity Based on Quantum Genetic-Neural Network Algorithm
LIU Chen-yang, TANG Xing-jia, YU Tao, WANG Tai-sheng, LU Zhen-wu, and YU Wei-xing
Dynamic viscosity is one of the most important quality factors of lubricating oil. For the safety of high-speed railway, it is necessary to develop a real-time, fast and non-destructive method to monitor the status of the gearbox. Here we propose a new method that utilizes the quantum genetic-neural network algorithm tDynamic viscosity is one of the most important quality factors of lubricating oil. For the safety of high-speed railway, it is necessary to develop a real-time, fast and non-destructive method to monitor the status of the gearbox. Here we propose a new method that utilizes the quantum genetic-neural network algorithm to quantitatively analyze the visible and near-infrared spectra of lubricant acquired by a micro-spectrometer module. The method not only realizes non-destructive rapid real-time detection of the dynamic viscosity of high-speed railway transmission lubricating oil, but also further improves the prediction accuracy of the lubricating oil dynamic viscosity. Thanks to its excellent performance and small size, the miniature spectrometer has been widely used as a portable and nondestructive device. Here, two kinds of micro-spectral modules with visible/short-wave-infrared and near-infrared waveguide gratings are coupled with optical fibers and obtain a wide spectral range from 330 to 1 700 nm. Here the integrated waveguide and propagating makes the spectrometer compact and small. In experiment, a total of 78 lubricant samples with 13 different viscosity lubricants were prepared for spectral measurement by the micro-spectrometer. The raw spectral data was pre-processed using the Savitzky-Golay convolution smoothing and the first-order differentiation to eliminate the baseline drift and background noise. Next, principal component analysis and Mahalanobis distance algorithm were used to identify the samples outside the concentration boundary, and three out-of-bound samples were excluded. Finally, the BP neural network and the quantum genetic neural network methods were employed for quantitative analyses and the results are compared, respectively. The quantum genetic algorithm is a probabilistic evolutionary algorithm that combines the advantages of quantum computing and genetic algorithm. It uses the form of quantum chromosomes and quantum logic gates for global searching. Therefore, the quantum genetic algorithm can be used to optimize the weight and the threshold of neural network, and the modeling efficiency and accuracy can be improved significantly. In this paper, BP neural network algorithm and quantum genetic neural network algorithm were modeled and simulated respectively. Ten samples were randomly selected from 75 samples as prediction sets, and the remaining 65 were as modeling sets. In the quantum genetic algorithm, the population number was set to 40 and the termination algebra was 200. The optimization results showed that the algorithm could obtain the optimal solution quickly after training of only 81 generations. A comparison of the predicted results showed that the quantum genetic algorithm was much better than the BP neural network, the root mean square error of the prediction was significantly reduced from 0.345 5 to 0.029 4, and the coefficient of determination was increased from 0.850 4 to 0.979 9. This work has developed an effective method for compact, non-destructive, rapid and real-time detection of the dynamic viscosity of the lubricant and would find potential uses for the safety monitoring of high-speed trains..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1634 (2020)
Qualitative Discrimination and Quantitative Determination Model Research of Methanol Gasoline and Ethanol Gasoline
HU Jun, LIU Yan-de, HAO Yong, SUN Xu-dong, and OUYANG Ai-guo
Methanol gasoline and ethanol gasoline are both clean energy sources, but the advantages and disadvantages of them are different. Among them, the content of methanol or ethanol determines the performance of gasoline. Therefore, it is of great significance to qualitatively distinguish methanol gasoline and ethanol gasolMethanol gasoline and ethanol gasoline are both clean energy sources, but the advantages and disadvantages of them are different. Among them, the content of methanol or ethanol determines the performance of gasoline. Therefore, it is of great significance to qualitatively distinguish methanol gasoline and ethanol gasoline and quantitatively determine the alcohol content in alcohol gasoline. In this paper, the types of alcohol gasoline and its content were identified and quantitatively analyzed by mid-infrared spectroscopy. Firstly, by comparing and analyzing the mid-infrared spectroscopy of methanol gasoline and ethanol gasoline, Random Forest (RF) was used to discriminate methanol gasoline and ethanol gasoline samples. After establishing the qualitative model of methanol gasoline and ethanol gasoline, the quantitative determination model of methanol gasoline and ethanol gasoline is established to accurately determine the corresponding alcohol content in gasoline. In order to reduce the spectrum drift and light scattering caused by vibration and noise of the experimental instrument during the experiment, the mid-infrared spectrum was pretreated. In the process of analysis, different pre-treatment methods are first used for correction, such as S-G convolution smoothing, Multivariate Scattering Correction (MSC), Standard Normal Variable (SNV), derivatives (1st derivative and 2nd derivative), and then, Least Square Support Vector Machine (LSSVM) models of methanol gasoline and ethanol gasoline were established respectively. It was found that the discriminant accuracy is up to 98.23% when the number of decision trees was 61. Secondly, for the LS-SVM model, the comparison of modeling results showed that for both methanol gasoline and ethanol gasoline, SNV pre-treatment had the best effect. The predictive correlation coefficient Rp of LSSVM model after the transformation of standard normal variables for methanol content determination of methanol gasoline was 0.951 9 and RMSEP was 1.766 3. In the same situation, ethanol gasoline was 0.951 5 and 1.770 3, respectively. This research can provide technical reference and theoretical basis for the qualitative discrimination and content determination of methanol gasoline and ethanol gasoline. The detection technology can provide a new method for the measurement of alcohol gasoline in the methanol gasoline industry, which has important practical significance and lays a foundation for the detection of other types of chemical products..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1640 (2020)
Study on River Water Quality Type Identification Method Based on Fluctuation Index of Second-Order Differential Spectra
LI Lan, TIAN Hua, JI Tie-mei, GONG Cai-lan, HU Yong, WANG Xin-hui, and HE ZHi-jie
Urban river water resources are important ecological resources. In recent years, the continuous development of urban industry has led to the increasingly prominent problem of river water pollution. The traditional sampling and testing methods have high precision, but it is time-consuming and laborious. This study propoUrban river water resources are important ecological resources. In recent years, the continuous development of urban industry has led to the increasingly prominent problem of river water pollution. The traditional sampling and testing methods have high precision, but it is time-consuming and laborious. This study proposes a rapid identification of water quality types based on the second-order differential fluctuation index of the spectrum. The method can realize rapid displacement of water quality types in urban rivers. The method first uses the spectral difference calculation to obtain the second-order differential curve of the spectrum, and smoothes the curve to eliminate noise and other disturbances; then uses the sliding window to extract the local maximum and minimum values on the curve, and sets the minimum distance threshold to gradually remove The extreme false point is obtained by using the cubic spline interpolation method to obtain the double envelope of the second-order differential curve of the spectrum. Finally, the fluctuation index curve of the second-order differential of the spectrum is calculated by using the upper and lower envelopes. After analyzing the fluctuation curves of various samples, it is found that the fluctuation indexes of various water bodies are different at 720~740, 750~770 and 820~840 nm, and then the average fluctuations of various water bodies in these three bands are counted. Statistical characteristics such as the mean value and standard deviation of the index show that the average fluctuation index has a positive correlation with the water quality level. The higher the water quality level, the worse the water quality condition and the larger the average fluctuation index. In order to verify the second-order differential fluctuation index of the spectrum, it can be used for the rapid identification of urban river water quality. The water body spectral samples are randomly divided into training sets and test sets, and LSSVM is used to construct the water quality type, identification model. The average fluctuation index is used as the character input. After testing, the average recognition accuracy of each type of sample is 80.65%, and the recognition accuracy of no more than one type exceeds 95%. The high-spectral identification method of river water quality based on spectral second-order differential fluctuation index proposed by this study has high recognition accuracy and can be used as an auxiliary technical means for rapid detection of urban river water quality types..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1645 (2020)
An Improved Hodrick-Prescott Decomposition Based Near-Infrared Adaptive Denoising Method
XIE De-hong, LI Jun-feng, LIU Di, WAN Xiao-xia, and YE Yi
During the rapid detection of pesticide residue in fruits and vegetables by near-infrared (NIR) spectroscopy, NIR spectroscopy is often contaminated by noises. Meanwhile, the peaks in NIR spectroscopy of chemical components of pesticides and fruits and vegetables are weak and highly overlapped, so denoising the NIR speDuring the rapid detection of pesticide residue in fruits and vegetables by near-infrared (NIR) spectroscopy, NIR spectroscopy is often contaminated by noises. Meanwhile, the peaks in NIR spectroscopy of chemical components of pesticides and fruits and vegetables are weak and highly overlapped, so denoising the NIR spectroscopy has risks of smoothing weak peaks of pesticide components or generating peaks of non- chemical components. In the subsequent classification or chemical composition analysis, the above problems deteriorate the accuracy of classification of the NIR spectroscopy and influence analysis of chemical components of pesticide residue. In order to solve the conflict between noise suppression and peak maintenance of the NIR spectroscopy, an adaptive denoising method is proposed based on an improved Hodrick-Prescott decomposition model. In the model, L2 norm of the residual between the noisy near-infrared spectroscopy and its restored spectroscopy is used as the residual term to describe the Gaussian noise structure, and L2 norm of the second-order difference of the restored spectroscopy is used as the regularization term to penalize the restored spectroscopy. The penalty can force the restored spectroscopy to reduce its gradient, resulting in smoothing noises and keeping the original peaks. In order to acquire the regularization parameter in the optimization equation of the Hodrick-Prescott decomposition model adaptively, an L-curve method is combined into the method. So in the method, the optimal regularization parameters are obtained by solving the parameters corresponding to the maximum curvature point of the L-curve, which can balance the regularization term and the residual term in the Hodrick-Prescott decomposition model and finally obtain ideal restored spectroscopy. In order to compare wavelet decomposition methods with bior6.8 basis and sym8 basis and complete ensemble empirical mode decomposition method, signal-to-noise ratio (SNR) is computed, and a support vector machine (SVM) classification model is established by NIR spectroscopy of Shanghai Qing with pesticide and without pesticide. The experimental results show that the SNR value of the denoised NIR spectroscopy can reach to 33.35 dB when using the proposed method to deal with the noisy spectroscopy with 18.79 dB. Then the method is applied to denoising the NIR spectroscopy in the training set and the testing set, the recognition rate of vector machine classification model trained by the training set and testing set are 93.58% and 71.18% respectively. This recognition rate is significantly higher than the results using the above three denoising methods and is close to the results of the original uncontaminated spectroscopy. The results validate that the proposed method has better denoising effect than other methods mentioned, which can improve the stability of NIR classification model to pesticide residue detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1650 (2020)
Near-Infrared LED Moisture Content Sensor for Traditional Chinese Medicine Based on Square Wave Excitation
ZHANG En-hua, QIU Xuan-bing, WEI Yong-bo, LI Ning, LI Jie, HE Xiao-hu, GUO Gu-qing, LI Chuan-liang, WEI Ji-lin, ZANG Zhen-zhong, and YANG Ming
Traditional Chinese medicines (TCMs) are in great demands around the world, and their popularity increased even more when Tu Youyou was awarded the 2015 Nobel Prize in Medicine. However, many key issues regarding the current quality standards remain and moisture content (MC) of TCM is one of the important elements of tTraditional Chinese medicines (TCMs) are in great demands around the world, and their popularity increased even more when Tu Youyou was awarded the 2015 Nobel Prize in Medicine. However, many key issues regarding the current quality standards remain and moisture content (MC) of TCM is one of the important elements of the quality control inspection. MC detection of TCM is usually implemented by using a voltage level or lock-in amplifier based on a Near-infrared Light-Emitting Diode (NIR-LED) absorption spectroscopy sensor. Square signal is frequently used as excitation source due to its abundant absorption features both in the time-domain and frequency-domain. However, the planeness, lift-off effect, and measurement noise negatively affect the time-domain features during MC measurement. A MC sensor has been developed to precisely measure the MC of Dutong pills based on NIR-LED spectrum analysis in this work. Firstly, a broadband NIR-LED with a central wavelength at 1 450 nm was adopted for the water absorption source. The spectrum features of the direct absorption signals were extracted by Fast Fourier Transform (FFT) algorithm. Secondly, the parameters of the excitation square signal were analyzed and optimized. The optimization results showed that the direct absorption spectrum signal was optimal when the excitation frequency, amplitude and duty ratio were set as 100 Hz, 1500 mV and 50% respectively. Finally, eight calibration groups with different MCs and four validation groups of Dutong pills were prepared. The linear relationship between the MC of the Dutong pills and the odd harmonic signal amplitude was established on the basis of the optimized square parameters of the excitation source. The calibration and validation results demonstrated the fundamental frequency components (100 Hz) and the 3rd harmonic components (300 Hz) have a high linear correlation with the MCs of the Dutong pills and the linear correlation coefficient R values were 0.992 and 0.993, respectively. The minimum measurement error and maximum error after averaging were 1.0% and less than 6.5%, respectively. The MC sensor took the square wave as excitation source. The noise of the water absorption spectrum signal was removed by wavelet filtering algorithm. The FFT algorithm was adopted to extract the feature of spectral signal. Therefore, the sensor has the advantages of high precision, wide applicability, real-time online measurement, and has the potential to be used for quality control and process analytical technology in TCM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1656 (2020)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 5, 1 (2020)
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