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2020 Vol. 40, No. 11
Published: 2020-11-01

 
3321 Inversion of Aerosol Optical Depth in the Beijing-Tianjin-Hebei Region Based on PSO Clustering Algorithm
WANG Shu-tao, WANG Gui-chuan*, FAN Kun-kun, WU Xing, WANG Yu-tian
DOI: 10.3964/j.issn.1000-0593(2020)11-3321-07
Aerosol optical thickness (AOD) is an important characterization parameter of aerosol concentration and atmospheric turbidity. Inversion of atmospheric AOD by remote sensing is an important way in the process of atmospheric monitoring and management, and in which the selection of methods suitable for the imaging characteristics of satellite sensors and the type of aerosols in line with the study area has always been the focus and difficulty of AOD inversion. In view of the problem that the traditional dark target method can not be directly applied to the multispectral remote sensing data of Gaofen Ⅳ (GF-4) satellite, this paper studies the distribution of the red and blue band equivalent surface reflectivity in GF-4 multispectral data and the linear relationship between them, and improves the dark target method to make it suitable for GF-4 satellite multispectral remote sensing data in combination with AOD inversion principle. The effect of input parameters on AOD inversion accuracy in the 6S radiation transfer model was analyzed, and the experimental results showed that aerosol type is one of the key factors affecting the high-precision inversion of AOD. The samples of aerosol characteristics in Beijing-Tianjin-Hebei area was analyzed by particle swarm optimization (PSO) cluster algorithm, by analyzing the proportion and half-life changes of the clustering results of each aerosol type, the C1 and C4 aerosol types in cluster results and the continental aerosol type of 6S models are finally determined to invert the AOD in Beijing-Tianjin-Hebei region. The inversion results were compared with MODIS aerosol products and AErosol RObotic NETwork (AERONET) ground-based site data, and the suitability and characteristics of different aerosol types are evaluated by evaluation criteria such as correlation coefficient and absolute error. The experimental results show that the C4 aerosol type, which is dominated by fine particles, is more satisfied with the characteristics of aerosols in the summer and autumn of Beijing-Tianjin-Hebei, and has better consistency with AERONET ground-based data. It is further proved that the PSO clustering algorithm can effectively reduce the influence of aerosol type difference on AOD inversion accuracy.
2020 Vol. 40 (11): 3321-3327 [Abstract] ( 184 ) RICH HTML PDF (3431 KB)  ( 111 )
3328 Phase Characterizing and Processing in Fourier Transform Spectroscopy
LIU Jia-qing1, 2, LI Zhi-zeng1, 4, LI Jing3*, LIU Lei1, 4, LIU Lei1, GUO Hong-long1, WANG Jian-guo1
DOI: 10.3964/j.issn.1000-0593(2020)11-3328-08
Phase correction is a critical procedure for Fourier transform spectrometers(FTS), whose accuracy can be jeopardized from instrument properties and many uncontrollable environmental conditions, such as significant temperature change of interferometer, mechanical disturbances. Nevertheless, a generally applicable phase correction method seems not available, since current research result in limitations of the standard methods and propose solutions tailored to specific instruments. Considering of phase uncertainly and the challenge of phase determination, the phase property of FTS is characterization and analysis,then to resolve the FTS phase into an instrumental phase that is dependent on the interferometer temperature and a linear phase component that accounts for the discrepancy between the actual interferogram zero optical path difference (ZOPD) and the sampled one. The instrumental phase is mostly an instrumental characteristic that can be identified along with the other calibration parameters, the instrumental phase is strongly affected by interferometer temperature fluctuation, the instrumental phase is constant with interferometer temperature changes within threshold; While linear phase is main attributable to the offset between the digitized ZOPD and the real ZOPD, but also a mainly component of FTS phase. According to the principle of FTS, ZOPD sample errors can change abruptly from one interferogram to another; as a result, each spectrum has a different linear phase with respect to the wavenumber. So the phase processing can be simplification as a linear phase correction, residual phase, including the instrumental phase was removed in radiometric calibration later. This work considers the temperature properties of instrument phase, the implemented method is based on the identification of linear phase by least-squares approach, with interferogram symmetrization, residuals phase of measured data is stabilization to permit spectra averaging, so the artifacts due to vibrations are removed, the last step is complex radiometric calibration procedure with mostly instrumental phase removed, and then the phase correction is accomplished. Based on experimental data, the linear phase terms are derived by the leasts-quares method and removed. Data were interpolated to model the instrumental phase using different order polynomials. A fifth-order polynomial fitting was eventually used with mean square errors(MSE) of 0.13 rad, because of a further reduction of MSE is not entail with the order increased. Instrumental phase with interferometer temperatures of 283, 290 and 300 K were taken by fifth-order polynomial fitting. Phase regression residuals with the instrumental phase and linear phase removed, stochastic distributed central at zero, the temperature dependence of the instrumental phase by theoretic is demonstrated by experiment. And then, the feasibility of the proposal phase processing method is experimentally validated. Experimental result shows that phase residuals within ±0.04 rad and the radiometric uncertainty sought 0.8 K accuracy or better is achieved.
2020 Vol. 40 (11): 3328-3335 [Abstract] ( 218 ) RICH HTML PDF (4179 KB)  ( 110 )
3336 Thermal Annealing Effect on Photoluminescence of Y2O3∶Eu3+ Thin Films Prepared by Magnetron Sputtering
LIN Shun-hui,ZHANG Li-hui, LIU Yong-quan, WANG Xiao-kun, LIN Chun-lei, YU Yun-peng*
DOI: 10.3964/j.issn.1000-0593(2020)11-3336-05
Fluorescent performance of rare earth doped luminescent film is closely related to post-annealing treatment. In order to explore the influence of thermal annealing on luminescence and structure of Y2O3∶Eu3+ thin films prepared by magnetron sputtering, three groups of the films with thickness of 100~150 nm were deposited on silica glass substrates under three different conditions respectively. Each group contained four samples, which were prepared under the same condition and annealed respectively at room-temperature, 700, 900 and 1 100 ℃ for 2 h in O2 ambience. The measurements of X-ray diffraction spectra (XRD), electron energy dispersion spectra (EDS) and photoluminescence spectra(PL)were conducted on the films, and the results were summarized as follow: Although the Y2O3∶Eu3+ thin films prepared under different sputtering conditions, the annealing effects on these films are found to be similar if they experience the same annealing process. Firstly, the PL excitation spectra indicate that charge transfer mechanism is responsible for the luminescence of all the films, and the characteristic wavelength (~252 nm) corresponding to this mechanism does not vary with the annealing temperature. Secondly, annealing treatment at 700 ℃ cannot significantly improves the crystallinity and the light emission intensity of the films. When annealing temperature reaches 900 ℃, the annealed film contains cubic phase Y2O3∶Eu3+ nanocrystallites, leading to the main peak at 612 nm enhanced significantly. However, as the temperature increased to 1 100 ℃, a phase transition from cubic to monoclinic occurs, and the film structure is dominated by the monoclinic phase. Although the content ratio of Eu to Y in the film is decreased to 0.05% after being annealed at 1 100 ℃, the light emission efficiency increases obviously. This result is ascribed to an improved crystallinity and a fact that there are more sites with anti-inversion symmetry in monoclinic lattice than in cubic one. In this case, not only is the red-light emission stronger, but also the main peak is shifted to 623 nm, which represents the characteristics of electric dipole transition 5D07F2 in monoclinic structure. Meanwhile, the luminescences from magnetic dipole transition 5D07F1 and electric dipole transition 50F0 are enhanced compared with those in cubic lattice. Especially for the 5D07F0, the intensity contrast between these two structures indicates obviously that the 581nm emission can be assigned to monoclinic phase Y2O3∶Eu3+ crystalline. This work demonstrates the features of the annealing effect on magnetron sputtering Y2O3∶Eu3+ thin film, and an alternative method for preparing Y2O3∶Eu3+ film with high luminescence efficiency, as well as the PL spectrum evolution induced by the phase transition from cubic to monoclinic.
2020 Vol. 40 (11): 3336-3340 [Abstract] ( 179 ) RICH HTML PDF (2106 KB)  ( 56 )
3341 Review on the Literature of X-Ray Fluorescence Analysis of Rare Earth Elements in Geological Materials
WANG Yi-ya1, GAO Xin-hua2, WANG Yi-min1*, DENG Sai-wen1, LI Song1
DOI: 10.3964/j.issn.1000-0593(2020)11-3341-12
The analysis of rare earth elements had been a hot topic in inorganic analytical chemistry, and it was also a big problem for a long time. In the 1960s and 1970s, the research upsurge in the composition of complex polymetallic rare earth minerals in Bayan Obo and the research upsurge in the geochemistry of trace rare earth elements in the 1970s and 1980s greatly promoted the development of rare earth element analysis technology of geological materials in China. In this paper, the literature of rare earth elements in China and the basic conditions of rare earth element analysis were reviewed from the aspects of Monographs on rare earth element analysis, national standard reference materials for rare earth ores, national standard analysis methods and review papers on rare earth element analysis. In this paper, 63 papers on XRF analysis of rare earth elements in geological materials from 1964 to 2018 in China were collected. The papers were mainly reviewed from three aspects: analysis of rare earth elements in ore minerals, trace rare earth elements in various geological materials and micro area in situ analysis of rare earth elements in ore minerals. In this paper, the historical contribution of XRF to the determination of REE in early rare earth ores and minerals was briefly introduced. Finally, the existing problems of XRF in the analysis of rare earth elements in geological materials are discussed and suggestions for future development were put forward. There were 126 citations in this paper.
2020 Vol. 40 (11): 3341-3352 [Abstract] ( 233 ) RICH HTML PDF (1999 KB)  ( 103 )
3353 Measurement of Speed Distribution of Kerosene Flame by Using Photothermal Deflection Spectroscopy
WANG Nan1, 2, 3, XUAN Hong-wen3, LI De-hua3, NIE Yu-xin3
DOI: 10.3964/j.issn.1000-0593(2020)11-3353-05
The measurement of flame velocity is one of the research interests on the combustion process and fluid diagnosis, as it is of key research significance for the analysis of combustion composition and propulsion dynamics. In spite of its high accuracy, laser Doppler velocity measurement has limited application due to the complexity of the measurement process and increased error rate in low-speed measurement, hence giving rise to the use of photothermal deflection spectroscopy for low and medium-speed fluid measurement. Photothermal deflection spectroscopy is based on the detection of the thermal lens on the tested medium. As components in the fluid medium absorb light and form a thermal lens distribution, when a probe beam is an incident on the medium, it is deflected due to the movement of the thermal lens. Fluid velocity is obtained by measuring the height of the probe beam relative to the pump beam, as well as the flight time corresponding to the signal deflection. This paper adopted a self-built pump device to study photothermal deflection. A pump beam with a single pulse energy of 20 mJ and wavelength of 355 nm, and He-Ne laser probe with the power of 2 mW were used to measure velocity at different positions of kerosene flame. The device has a spatial resolution of 2×10-5 cm3. Velocity was measured at planes with distances of 5, 8 and 11 mm from the kerosene wick, to obtain the distribution of horizontal velocity corresponding to the flame. The external velocity of the flame at the same horizontal plane was found to be higher than the internal velocity near the bottom of the flame; in the position near the top of the flame, the internal velocity of the flame at the same horizontal plane was higher than the external velocity; velocity distribution along the same plane was close to parabolic distribution. Velocity distribution of the three vertical planes ±2 mm away from the center of the flame was measured, to obtain the distribution of the corresponding vertical planes. Velocity on the central vertical axis near the bottom of the flame was found to be slower than that of both sides, and the velocity of the upper part of the flame was faster than that of both sides. This was consistent with the conclusions obtained from the earlier measurements of horizontal velocity distribution. The flame speed measured in the experiment ranged from 0.2 to 1.5 m·s-1. This paper used pump beams with single-pulse energy of 20, 40 and 60 mJ, to analyze the errors introduced by dielectric breakdown during velocity measurement. Results indicate that a larger error is introduced by higher laser energy. A velocity error of 0.1 m·s-1 was introduced by the 40 mJ beam, while a velocity error of 0.6 m·s-1 was introduced by the 60 mJ beam. With the further optimization of signal-to-noise ratio, photothermal deflection spectroscopy shall enable the measurement of parameters, such as temperature and concentration, thus making it a powerful tool for fluid velocity measurement and combustion diagnostics.
2020 Vol. 40 (11): 3353-3357 [Abstract] ( 165 ) RICH HTML PDF (2555 KB)  ( 62 )
3358 Application of Chemiluminescence in Spectral Diagnosis: A Review
ZHOU Ying1, BAI Yong-hui1, SONG Xu-dong1*, YAO Min3, WANG Jiao-fei1, SU Wei-guang1, YU Guang-suo1,2*
DOI: 10.3964/j.issn.1000-0593(2020)11-3358-07
Flame diagnosis technology refers to the use of spectrum, image, noise and other sensing means to obtain flame state and other information, through the obtained information to analyze the combustion and gasification state of flame. The development of combustion process diagnosis and optimizing diagnosis methods is one of the challenges facing the combustion industry. The improvement of combustion diagnosis technology can enhance the monitoring of efficiency, reliability and flexibility of different fuels. The flame spectrum diagnosis can determine the position of the flame and the equivalence ratio etc. Flame spectral diagnosis can also explore the characteristics of flame, such as instantaneous species etc. A comprehensive understanding of the combustion process can be achieved by means of spectral diagnosis. Due to the laser diagnosis method has the characteristics of a complex system and strict environmental requirements, chemiluminescence-based detection methods are getting more and more attention. The purpose of this paper is to describe the research progress and development trend of chemiluminescence. It mainly introduced the generation mechanism of chemiluminescence, Chemiluminescence reaction mechanism model and main production rate of intermediate combustion products (OH* , CH* and C*2). Meanwhile, it summarized the application of flame spectrum diagnosis technology in the research of intermediate combustion products. Chemiluminescence can be used to reflect the heat release rate. Chemiluminescence peak intensities can be used to indicate the peak position of temperature. The relationship between the peak intensity of chemiluminescence and the equivalent ratio is briefly reviewed. Chemiluminescence can be used to indicate the height of lift-off flame, and the flame structure characterization based on the image processing is reviewed. The application of chemiluminescence as a diagnostic tool is affected in flames containing additional background radiation and the measurement of CH* chemiluminescence will also be obscured by the black body radiation are also discussed. The application prospect of flame spectrum diagnosis technology in the future has further prospected. More detailed combustion reaction mechanisms are needed to be revealed. The effect of turbulence on combustion needs to be reduced. Soot affects the accuracy of the flame image is needed to be reduced and the accuracy of cameras and spectrometers are needed to be improved in the future. The on-line measurement methods of image and techniques of chemiluminescence spectroscopy have important scientific development significance and broad engineering guidance significance for promoting the research in the fields related to combustion and flow.
2020 Vol. 40 (11): 3358-3364 [Abstract] ( 276 ) RICH HTML PDF (3590 KB)  ( 309 )
3365 Current Status of High-Throughput Plant Phenotyping for Abiotic Stress by Imaging Spectroscopy: A REVIEW
CAO Xiao-feng1, 2, 3, YU Ke-qiang1, 2, 3, ZHAO Yan-ru1, 2, 3*, ZHANG Hai-hui1, 2, 3*
DOI: 10.3964/j.issn.1000-0593(2020)11-3365-08
Abiotic stress refers to the abiotic factors that have adverse effects on plants and threatens plants germination, growth, development and reproduction and hinders crops cultivation and agricultural sustainable development. Plants stress precision management and stress-resistance breeding are effective ways to alleviate and solve stress, in which plant phenotyping is an indispensable segment, but traditional lagged methods such as artificial destructive phenotype measurement are difficult to obtain high throughput phenotypes and restrict plant stress management precision and modern breeding efficiency. High throughput plant phenotyping (HTPP) technology, aims to acquire and analyze complex plant traits quickly, automatically and nondestructively, could rapidly monitor plant status in situ for precision input to control abiotic stress and could also provide solutions for high throughput screening and identification for excellent varieties and phenotype big data for revelation & mapping of resistance genes and genetic variation analysis. Latterly, imaging spectroscopy had shown good potential in high-throughput plant phenotyping due to its advantages in real-time, noninvasive and repeatable measurement for multiple phenotypes and had been widely used in precision agriculture and breeding. The papers mainly introduced the studies of high-throughput plant phenotyping for abiotic stress by imaging spectroscopy including visible light imaging (RGB), multispectral imaging (MSI), hyperspectral imaging (HSI), chlorophyll fluorescence imaging (ChlFI), multispectral fluorescence imaging (MFI) and thermal infrared imaging (TIRI) and estimated their development trends. Firstly, the technical characteristics and application differences for plant phenotyping and high-throughput plant phenotyping frameworks of imaging spectroscopy were briefly introduced. Secondly, some recent studies on plants stress monitoring, plant varieties screening & identification, genetic analysis for drought, temperature, salinity, nutrient and other stress by imaging spectroscopy were summarized. Finally, the chances and challenges of imaging spectroscopy in high-throughput plant phenotyping for abiotic stress were discussed.
2020 Vol. 40 (11): 3365-3372 [Abstract] ( 228 ) RICH HTML PDF (2591 KB)  ( 123 )
3373 Structural Characterization and Molecular Model Construction of Gas-Fat Coal With High Sulfur in Shanxi
GE Tao1,2, LI Yang1, WANG Meng2, LI Fen1, ZHANG Ming-xu1
DOI: 10.3964/j.issn.1000-0593(2020)11-3373-06
Gas-fat coal is one of the main coal types of coking coal. To study the structure of high sulfur gas fat coal and construct a molecular structural unit model is of great significance for desulfurization and upgrading, optimizing coking coal blending and saving high quality coking coal resources. The high sulfur gas-fat coal in Gaoyang mining area in Shanxi was selected. Its carbon, oxygen, nitrogen and sulfur structural characteristics were characterized by FTIR, 13C CP/MAS-NMR and XPS. The molecular structure unit model of Gaoyang high sulfur gas-fat coal was constructed by combining the results of coal quality analysis, calculate aromatic structure, fat structure and hetero atom structure parameters. The results show that the hydroxy π hydrogen bond formed by π electrons on the aromatic ring is the most important hydroxy structure of Gaoyang high sulfur gas fat coal, accounting for 73.20%. Hydroxyl self-association hydrogen bond, ether oxygen bond and hydroxyl group form a high hydrogen bond content, accounting for 24.38% of the total hydroxyl groups. The free hydroxyl content is only 2.42%, and the association structure in coal is mainly in the form of the multimer. Conjugated carbonyl and phenolic hydroxyl are mainly forms of the oxygen containing functional groups. The aryl ether and carboxyl groups are low. Methylene is the most important aliphatic hydrocarbon structure. Accounting for 41.85%. The proportion of methyl and methine groups was 29.86 and 28.29% respectively. The aromatic hydrocarbon structure mainly has three forms of benzene ring penta-substituted, benzene ring tri-substituted and benzene ring tetra-substituted, accounting for 41.42%, 30.65% and 19.82%, respectively. The aromatic hydrogen ratio and the aromatic carbon ratio is 0.34~0.35 and 0.73~0.77 respectively. The average structure size of the aromatic nucleus Xb was 0.43. The contents of thiophene, (sub)sulfone, thioether (thiol) and inorganic sulfur in coal is 35.90%, 27.61%, 18.40% and 18.09% respectively. Nitrogen is mainly present in the structure of pyridine and pyrrole, with less protonated pyridine and nitrogen oxides. The molecular structure unit has 118 aromatic carbon atoms, 5 carboxyl groups and carbonyl groups, 35 aliphatic hydrocarbon atoms, and 8, 2, 2 oxygen, sulfur and nitrogen atoms. According to the analysis of the structure of heteroatoms in coal. It is determined that the molecular structure model unit contains functional groups such as thiophene, sulfoxide, pyridine, pyrrole, phenolic hydroxyl group, ether oxygen bond and the like. The molecular structure unit model of high-yang high-sulfur gas fat coal with molecular formula C165H128O8N2S2 was constructed.
2020 Vol. 40 (11): 3373-3378 [Abstract] ( 200 ) RICH HTML PDF (2307 KB)  ( 47 )
3379 Research on Variable Angle Fiber-Type Terahertz Time-Domain Spectrometer
LI Zheng1,2, SUN Qing2*, FENG Mei-qi2, SHANG Liang1, DENG Yu-qiang2, LI Chao-chen2
DOI: 10.3964/j.issn.1000-0593(2020)11-3379-05
Terahertz time-domain spectroscopy (THz-TDS) technology is widely used in many fields such as material composition identification, explosive detection, drug and drug composition analysis, and medical diagnosis. The traditional THz-TDS uses a Ti: sapphire femtosecond laser as a light source, which is bulky and costly, and limits the large-scale application of THz-TDS. Using a fiber femtosecond laser combined with a fiber-coupled terahertz photoconductive antenna, the THz-TDS system can be designed to be very compact and flexible, while eliminating the need for a free-space optical path, greatly reducing the number of optical mounts The influence of external environment on the signal such as vibration has great application potential in industry and in the field. In this paper, a fiber-type THz-TDS system is designed and developed, and the three subsystems of optics, electricity and software are briefly introduced. The femtosecond pulse width is controlled by fiber dispersion management, so that the femtosecond pulse width of the terahertz photoconductive antenna is kept at about 50 fs, thereby eliminating the terahertz time domain pulse broadening caused by femtosecond pulse broadening. By precisely controlling the polarization state of the femtosecond laser, the polarization direction of the pump laser and the detection laser is kept parallel with the fast or slow axis of the polarization maintaining fiber, thereby eliminating the splitting phenomenon of the terahertz time domain pulse and obtaining the signal to noise ratio. Better than 12 000 single-pulse terahertz time domain waveforms. The variable angle optical path structure design enables easy switching of terahertz transmission spectrum measurement and reflection spectrum measurement, as well as the measurement of variable angle terahertz spectrum.
2020 Vol. 40 (11): 3379-3383 [Abstract] ( 174 ) RICH HTML PDF (4049 KB)  ( 78 )
3384 Study on Internal Quality Nondestructive Detection of Sunflower Seed Based on Terahertz Time-Domain Transmission Imaging Technology
LIU Cui-ling1, 2, WANG Shao-min1, 2, WU Jing-zhu1, 2, SUN Xiao-rong1, 2
DOI: 10.3964/j.issn.1000-0593(2020)11-3384-06
The quality of the kernels in the sunflower seed shell directly affects the quality of the edible oil. Using terahertz time-domain transmission imaging technology combined with morphological filtering and K-means image segmentation, the three abnormalities of sunflower seed like kernel damaged, kernel worm-eaten and empty seed were investigated to achieve to explore the quality of seed kernels in sunflower seed hull. According to the national standards and previous experience, three kinds of shelled sunflower seeds samples of kernel damaged, kernel worm-eaten and empty shells were prepared. The terahertz time domain spectrometer TeraPulse 4000 and transmission imaging accessory were used to acquire the spectral images of the above three abnormal samples at a resolution of 0.2 mm, and a spectral image of normal sunflower seed was taken as a reference. Four sunflower seed terahertz images were reconstructed by peak-to-peak imaging. The terahertz images can preliminarily determine the shape of the seed kernel in the shell, but there were still problems such as low contrast and blurred edge information, which needed further optimization. The morphological filtering algorithm was used to filter the terahertz images of sunflower seeds. The flat diamond structure element with a side length of 3 was selected as the collation image for one expansion, and then the external gradient of the image was calculated to complete the filtering process of the image. At the same time, the morphological filtering results were compared with the median filtering results, the mean filtering results and the non-local mean filtering results. It was found that the morphological filtering not only ensured the sharpness of the image, but also preserved the edge information, and could also make an obvious boundary between the sunflower seed sample and background, which was conducive to subsequent image segmentation processing. In order to more accurately detect the shape of the sunflower seed kernel, the filtered images were segmented. The K-means clustering algorithm was used to segment the filtered terahertz images. In order to improve the accuracy of the segmentation results, the number K of different initial cluster centers was determined for the images of different samples, among which the kernel damaged K=4, the worm-eaten kernel K=5, the empty shell K=3, the normal grain K=4. The segmented images accurately showed the morphology of the kernels in the sunflower seed hull. The study showed that the terahertz time-domain transmission imaging technique combined with morphological filtering and K-means image segmentation method was feasible for the non-destructive detection of the internal quality of sunflower seeds, which laid a foundation for the establishment of non-destructive testing model for the quality of shelled sunflower seeds, and provided a new method reference for nondestructive detection of the internal quality of shelled oil crops.
2020 Vol. 40 (11): 3384-3389 [Abstract] ( 184 ) RICH HTML PDF (3446 KB)  ( 457 )
3390 Raman Spectroscopy for Gas Detection Using a Folded Near-Concentric Cavity
LIU Qing-sheng1, YANG De-wang2, GUO Jin-jia1*, YAN Ao-shuang1, ZHENG Rong-er1
DOI: 10.3964/j.issn.1000-0593(2020)11-3390-04
Raman spectroscopy is used in many fields with advantages of no sample pretreatment and simultaneous multiple species detection, while the disadvantage of low sensitivity limits its further a pplication. In order to improve the sensitivity of Raman gas detection, a method for enhancing the gas Raman signal based on a folded near-concentric cavity is reported in this paper. By inserting a high reflectivity plane mirror into the center of multiple reflectors, the cavity body is folded from the center, so that the beams in the center of the cavity overlap with each other to increase the light density and luminous flux, thereby improving the detection sensitivity of the system. Ray tracing and flux analysis are performed on the different cavity modes using TracePro software(laser: 300 mW@532 nm,reflectance:99%@532 nm). The results show that the optical cavity folding method can significantly increase the optical flux at the center of the reflecting cavity. When the number of reflections in the folded near concentric cavity is 68 times, the luminous flux at the center of the waist is 22.35 W, which is about 1.5 times enhancement compared with the unfolded near-concentric reflecting cavity. In order to verify the simulation results, a gas detection Raman spectroscopy system with folded near-concentric cavity is set up. The experimental results show that the folded near-concentric cavity has the best enhancement, reaching 49 times; next is near concentric cavity about 36 times; the third is folding the concentric cavity, a pproximately 24 times; the last is the concentric cavity, just 17 times. The signal-to-noise ratio of the gas Raman signal collected by the folded near-concentric cavity is 1.4 times higher than that of the unfolded near-concentric cavity. According to the relative intensity of the carbon dioxide Raman peak in the air, we can calculate the limit of detection for CO2 using 3-σ criterion standard with the value of 0.13 mg·L-1 (66 ppm).
2020 Vol. 40 (11): 3390-3393 [Abstract] ( 201 ) RICH HTML PDF (2395 KB)  ( 86 )
3394 Influence of Incident Angle and Polarization on Spectral Behaviors of Tapered Silicon Nanowire
TONG Jie1, LEI Yu-qing1, LI Ying-feng2*, LI Mei-cheng2, ZHANG Ming-hao1, GAO Zhong-liang2
DOI: 10.3964/j.issn.1000-0593(2020)11-3394-05
The extinction section of a silicon nanowire can reach hundreds of times its geometric cross-sectional area at a given wavelength, meaning it can collect light in the area a scope hundreds of times of its geometrical cross-sectional area. Therefore, silicon nanowire has been widely used in many optoelectronic fields like solar cells, sensors, and photocatalysis devices. Cylindrical silicon nanowire (C-SiNW) and tapered silicon nanowire (T-SiNW) are the two most important silicon nanowire structures. Between them, the extinction efficioncy of T-SiNW has a wider waveband with a large extinction efficiency, so it shows better ability to collect broad-spectrum light. Nevertheless, when under top irradiation, the absorption efficioncy of T-SiNW is quite small, which severely limits its practical applications. It is urgent to find out the law that the incident angle affects the spectral behaviors of T-SiNW. Besides, the polarization of incident light will also influence the spectral behaviors of T-SiNW. In this work, the influence of angle and polarization of incident light on the extinction, absorption spectra and scattering properties of T-SiNW was carefully studied, using the discrete dipole approximation method. T-SiNW was modeled with the length of 1 μm, top-diameter of 20 nm, and bottom-diameter of 120 nm; the angle of incident light increases from 0° to 180° with an interval of 30 °; and two polarization states, parallel and vertical to the incident plane, were considered. First, impacts of the incident angle and polarization on the extinction, absorption spectra, and the ratio of the absorbed light (Abs./Ext.) of T-SiNW were studied. Meanwhile, the mechanisms for the spectral behaviors of T-SiNW were discussed by means of analyzing the near-field distribution mappings. Then, the influence of the angle and polarization on the scattering angle distribution of T-SiNW was analyzed. The results show that the fully inverted T-SiNW has the same extinction spectrum as the upright one, but its absorption spectrum increases significantly: the average Abs./Ext. ratio exceeds 70% in waveband ranging from 0.3 to 0.55 μm. The horizontally placed T-SiNW has the largest extinction spectral value and the smallest absorption spectral value, so it shows the strongest light collection ability whereas the smallest light absorption ratio. Meanwhile, it can scatter the vertical incident light in approximate horizontal directions. In addition, T-SiNW shows larger absorption spectral values for parallel-polarized light than vertical-polarized light, but smaller Abs./Ext. ratio.
2020 Vol. 40 (11): 3394-3398 [Abstract] ( 160 ) RICH HTML PDF (3592 KB)  ( 45 )
3399 Preparation and Properties of Ag/PANI Multifunction Nanozymes
ZHANG Lei, ZHANG Xia*, WENG Yi-jin, LIU Xiao
DOI: 10.3964/j.issn.1000-0593(2020)11-3399-05
Surface-Enhanced Raman Scattering (SERS) is an analytical test technique that uses metal or metal nanoparticles as a detection substrate. It can be used to characterize molecular vibration information with good reproducibility and stability. Nanozymes are nanomaterials with catalytic functions. In recent years, the research on the catalytic activity of nanozymes has developed rapidly, which has aroused extensive research interest in biology and medicine. Nanozymes can avoid the characteristics of easy inactivation of biological enzymes, exhibits high stability and good catalytic performance in water or buffer solution. It has broad application prospects in the field of catalysis and enzyme kinetics due to its catalytic activity and simple preparation method. However, the research on the combination of SERS technology and the simulation of the catalytic activity of biological enzymes is limited. Most of the studies use UV-visible absorption spectroscopy to analyze the catalytic performance of nanozymes. In this paper, Ag nanoparticles in the PANI matrix were prepared by one-step self-assembly redox polymerization. In the polymerization of aniline, a composite of AgNO3-(3-aminopropyl) triethoxysilane (APTES) acts as oxidants and structure inducers; then the reduction of AgNO3 is accompanied by the oxidation of aniline, resulting in the formation of Ag nanoparticles within a PANI matrix. It can be found that nanocomposite can function as not only peroxidase and glucose oxidase, but also tandem enzyme, which directly reflect glucose concentration by oxidizing TMB. Therefore, SERS technology and simulated enzyme catalysis research are combined in this paper, and SERS technology is used to detect H2O2, glucose and TMB more quickly and effectively.
2020 Vol. 40 (11): 3399-3403 [Abstract] ( 195 ) RICH HTML PDF (3297 KB)  ( 42 )
3404 Study on Plasma Temperature and Electron Density During Arc Initiation by Underwater Wet Welding
LI Zhi-gang, XU Xiang, LI Yang, HUANG Wei
DOI: 10.3964/j.issn.1000-0593(2020)11-3404-05
Underwater wet welding technology has been widely used in recent years, however, there is a lack of research on its mechanism. In this paper, the plasma temperature and electron density of the arc-inducing process of underwater wet welding are studied by means of spectral analysis. Firstly, the underwater wet welding arc spectrum diagnostic platform was built, and the current, voltage and spectral signals in the welding process were collected synchronously. The arc strike process is defined based on the analyzed current and voltage signal data. On this basis, the spectral signals of 5, 10, 15, 20 and 25 ms are collected by the time delay recording function of the spectrometer. The Fe element line and the H element line required to calculate the plasma temperature and ionization density are calibrated. In order to ensure the accuracy and reliability of the calculation results, five sets of data were selected at different times of the arcing, and the five sets of data were averaged. Five suitable spectral lines were selected in the calibrated Fe element line, and the underwater wet welding arc plasma temperature at different times of the arcing was calculated by Boltzmann diagram method. According to the Hα spectrum detected by the spectrometer, combined with the Stark line broadening theory of plasma emission spectroscopy, the electron number density at different moments of underwater wet welding arc is calculated. The calculation results show that the temperature changes of underwater wet welding arc plasma show different characteristics at different moments of arc ignition,In the arcing 5 and 20 ms respectively, the temperature values appear peak respectively, and the temperature value reaches 4 414 K at the last steady arc time. The electron number density also differs at different times of the arcing, and also peaks at 5 and 20 ms. The changing trend of arc plasma temperature and electron number density at different timings of arc ignition verified the formation of arc accompanied by the breakdown of space gap. The calculation results can further explore the physical nature of underwater wet welding arc-ignition process from the perspective of arc physics, and provide an important reference for guiding and seeking more effective arc-ignition methods.
2020 Vol. 40 (11): 3404-3408 [Abstract] ( 186 ) RICH HTML PDF (2244 KB)  ( 62 )
3409 Preparation of ZnSe/ZnS Core-Shell Quantum Dots Under UV Irradiation
ZHANG Cong-cong1, LIU Lian-dong2, XIA Lei1, LI Xue3, ZHANG Xiao-kai1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3409-07
In order to improve the traditional water phase method,ZnSe/ZnS core-shell quantum dots were synthesized at room temperature by ultraviolet irradiation method, which is more safe, simple, economical and environmentally friendly. The optimal growth and modification conditions for the core-shell structure of ZnSe/ZnS QDs were optimized by adjusting the experimental conditions such as pH value, illumination time and reactant ratio, so that it has good dispersion, time stability and luminescent properties. Ultraviolet irradiation can stimulate free electrons to trigger chemical reactions. In this study, thioglycolic acid (TGA) and glutathione (GSH) were used as both stabilizers and dispersants to control the growth of QDs and obtain evenly dispersed QDs. The introduced photosensitive material is also the S source to form ZnS. The crystal structure and optical properties of QDs were characterized by X-ray diffraction (XRD), electron microscopy (EM), Energy Dispersive X-ray spectroscopy (EDX), photoluminescence spectroscopy (PL) and UV-Vis. The results show that GSH-modified QDs have better stability and fewer surface defects than TGA-modified QDs. ZnS shell growth can effectively improve this defect, but the over-thick shell will lead to a risk of quenching the intrinsic radiation. This experiment explored this preparation method in-depth, and for the first time,various influencing factors and synthetic conditions were supplemented. Based on the analysis of the theory and the experiment results, the optimal synthesis conditions of ZnSe/ZnS core-shell quantum dots are obtained.
2020 Vol. 40 (11): 3409-3415 [Abstract] ( 175 ) RICH HTML PDF (5338 KB)  ( 71 )
3416 Infrared Spectrum and Thermodynamic Studies of Catechin-Black Rice Anthocyanin Complex
XIANG Ying1, FENG An-di2, ZHAO Zheng-zhuo1, SUN Cong-dan1, XU Hao-peng1, SUN Li-na1, XIE Feng-ying1, 3*
DOI: 10.3964/j.issn.1000-0593(2020)11-3416-04
Catechin-black rice anthocyanin complex was chemically synthesized by black rice anthocyanin using acetaldehyde-mediated. The reaction mechanism of catechin - black rice anthocyanin complex was determined by infrared spectrum and thermodynamic parameters. The results showed that the catechin-black rice anthocyanin complex had a wide and strong absorption peak of —OH stretching vibration region at 3 207.90 and 3 217.90 cm-1, and appeared the benzene ring skeleton vibration absorption peak at C═C stretching vibration region around 1 604.92 and 1 605.65 cm-1. The infrared absorption peaks appeared at 1 278.01, 1 138.34 and 1 018.19 cm-1 in the 1 300~1 000 cm-1 C═O telescopic vibration region. It can be concluded the catechin-black rice anthocyanin complex and black rice anthocyanin had basically same structure framework with the main structure of aromatic ring structure —OH, C═C and C═O substituted groups. Compared with black rice anthocyanin, of catechin-black rice anthocyanin complex had the absorption peak not only at 1 604.92 and 1 493.59 cm-1, but also at 1 454.78, 1 233.98 and 817.56 cm-1. Based on absorption peak assignment, it was found that the absorption peak at 1 454.78 cm-1 belonged to —CH3 antisymmetric deformation or —CH2 deformation vibration band, which proved the existence of “ethyl bridge” in catechin-black rice anthocyanin complex. It was confirmed that there was condensation reaction between catechin and black rice anthocyanin. The appearance of absorption peaks of 817.56 and 1 233.98 cm-1 indicated that the plane valence bonds of some groups bent after the condensation reaction between catechin and black rice anthocyanin, which increased the polarity of CO bond. In addition, the results of thermodynamic parameters showed that the condensation reaction between catechin and black rice anthocyanin was endothermic and non-spontaneous, and the structure of catechin-the black beige complex was stable.
2020 Vol. 40 (11): 3416-3419 [Abstract] ( 195 ) RICH HTML PDF (1366 KB)  ( 54 )
3420 Research on the Spectra Characteristics and Catalysis Effects of Nanosized Ce0.95M0.05O2 (M=Fe, Nd, Eu) Solid Solutions
ZHANG Guo-fang1, HU Feng1, XU Jian-yi1, YU Hai-shu1, GE Qi-lu2, ZHANG Yang-huan1,2
DOI: 10.3964/j.issn.1000-0593(2020)11-3420-05
Nanosized Ce0.95M0.05O2(M=Fe3+, Nd3+, Eu3+) solid solutions were synthesized via hydrothermal method. The micro-crystalline structure and spectra characteristics were investigated systemically. X-ray diffraction (XRD) results showed that doped samples exhibited single phase fluorite cubic structure,while no impurity phases corresponding to the doped ions oxides were observed. This result indicated that the doped ions had been doped into the lattice of CeO2 and formed solid solutions. The crystalline sizes of the samples were calculated lower than 20 nm. The electron transition properties of the solid solutions were characterized by UV-Vis spectra. Red-shift of absorption edges of the doped solid solutions was observed. Meanwhile, the band gap energies were fitted and it was found that the obtained values from large to small is CeO2 (3.13 eV)>Ce0.95Eu0.05O2 (3.04 eV)>Ce0.95Nd0.05O2 (2.94 eV)>Ce0.95Fe0.05O2 (2.75 eV). The photoluminescence (PL) spectra displayed that the intensities of the doped sample emission peaks were lower than that of pure CeO2. Among them, the peak of the solid solution with Fe3+ ions possessed the lowest intensity. It can be explained that the doping of Fe3+ ions would introduce more defects in the lattice, which would hinder the recombination of electrons and holes. The solid solutions were added into Mg2Ni-Ni as catalysts and the Mg2Ni-Ni-5%Ce0.95M0.05O2 composites were obtained via ball milling method. The electrochemical and dynamic hydrogen storage performances were tested systematically. It was showed that the Ce0.95M0.05O2 solid solutions could improve the electrochemical discharge properties, the maximum discharge capacities were Ce0.95Fe0.05O2 (874.8 mA h·g-1) >Ce0.95Nd0.05O2 (827.8 mAh·g-1) >Ce0.95Eu0.05O2 (822.7 mA h·g-1) >CeO2 (764.9 mAh·g-1), respectively. Meanwhile, the catalysts also could enhance the electrochemical cycle stabilities of the composites effectively. The capacity retention ratio after 20 cycles were Ce0.95Fe0.05O2 (49.8%)>Ce0.95Eu0.05O2 (49.7%)>Ce0.95Nd0.05O2 (46.3%)>CeO2 (34.1%). The high rate discharge (HRD) properties of the composites were characterized, and it was proved that the solid solutions catalysts could improve the large current discharge performances of the composites. For instance, when the discharge current density was 200 mAh·g-1, the HRD were Ce0.95Fe0.05O2 (59.5%)>Ce0.95Eu0.05O2 (57.4%)> Ce0.95Nd0.05O2 (55.7%)>CeO2 (54.4%). The influence of the catalysts on the H diffusion capacity in the composites was evaluated by constant potential step technique, and the H diffusion coefficient was: Ce0.95Fe0.05O2>Ce0.95Eu0.05O2>Ce0.95Nd0.05O2>CeO2. The catalysis effects of the solid solutions were closely related to the concentration of oxygen vacancies, lattice defects in the lattice and the characteristic of easy to change valences of the doped ions.
2020 Vol. 40 (11): 3420-3424 [Abstract] ( 162 ) RICH HTML PDF (3278 KB)  ( 54 )
3425 Study on Leakage Detection Technology of Corrosive Acid Solution Based on Fiber Raman Temperature Measurement
FENG Wei-yi1, 2, LIU Li-hua1*, ZHANG Xu-ping2, ZHAO Xia1, HUANG Xiao-wei1, YU Chun-han3
DOI: 10.3964/j.issn.1000-0593(2020)11-3425-05
Distributed Temperature Sensing System (DTS) is based on the effect of Raman spectrum on temperature sensitivity. It can realize long-distance distributed temperature monitoring, especially suitable for fire alarm, high-temperature liquid leakage, low-temperature gas leakage and other application scenarios. However, for normal temperature media, such as highly corrosive solutions transported in chemical pipelines, when corrosion occurs in the pipeline infiltration, there is basically no temperature change between the leakage location and the surrounding environment. At this time, DTS temperature measurement technology is difficult to identify the occurrence of leakage events. In order to solve the problem of leakage detection of strong acid solution pipelines or tanks under normal temperature, in this paper, a technology based on optical fiber sensing to detect the leakage of acid solution medium was proposed. A novel self-sensing structure of acid solution was designed. Compared with leaking cable, it does not need to consume electricity and is not easy to cause a false alarm. Precise positioning and simple laying. Multi-point leakage detection can be realized across the pipeline. Fiber optic cable outer sheath material is alkali resistant and acid-resistant material, composed of nylon, magnesium hydroxide, aluminum hydroxide and a small number of colors masterbatch. It can be dissolved quickly by hydrochloric acid with the certain mass fraction. Exothermic chemical neutralization reaction occurs. Then the Raman spectrum of backscattering in the sensor fiber is changed, and the temperature of the sensor fiber can be increased by more than 5℃. The sensing fiber optic cable is connected to the DTS system, and the system adopts the dual demodulation method based on anti-stokes light and stokes light to calculate the temperature value of each position in the sensing fiber. Therefore, when the special optical cable and pipeline are laid in the same ditch, if acid solution leakage occurs in a certain position, resulting in the temperature rise of the point. After the dispersion compensation and the temperature calibration, the acid leakage event can be determined, according to the ratio change between the anti-stokes light and the stokes light. This technology not only solves the problem of engineering application of leakage detection and alarm in the transportation and storage of acid solution but also avoids the interference of false alarm of weak acid or alkali solution, saving energy and protecting the environment. It can accurately detect the leakage of the highly corrosive acid solution and improve the digital intelligent safety monitoring level of hazardous chemicals.
2020 Vol. 40 (11): 3425-3429 [Abstract] ( 252 ) RICH HTML PDF (2133 KB)  ( 49 )
3430 Study on Near-Infrared Spectrum Features and Identification Methods of Typical Coal-Rock in Dust Environment
XIANG Yang, WANG Shi-bo*, GE Shi-rong, WANG Sai-ya, ZHOU Yue, LÜ Yuan-bo, YANG En
DOI: 10.3964/j.issn.1000-0593(2020)11-3430-08
In order to study the dust problem existing in the identification of near-infrared coal and rock in the underground coal mine, the mixture of anthracite and the anti-explosive agent was used to simulate the dust environment of coal mine underground so that the experimental device for spectral identification of coal and rock in dust environment was constructed. 23 samples of in-situ typical coal samples of shale, sandstone and limestone samples and anthracite, bituminous coal and lignite coal samples were collected from all over the country. 23 coal and stone samples reflection spectrum collecting without the dust of the near-infrared band (1 000~2 500 nm) was used as an experimental standard database. 1 sample was randomly selected from the three typical coal samples and three typical rock samples in the experimental standard the sample library as experimental samples, and the test samples’ reflectance spectra of the near-infrared bands at 600, 1 000, 1 500 and 3 000 mg·m-3 dust concentrations were collected. The results showed that the addition of dust led to a decrease in the signal-to-noise ratio of the spectral image between 1 000~1 200 and 2 400~2 500 nm; With the increase of dust concentration, The opaque substance of anthracite in the dust made the characteristic absorption valley in the experimental sample weaken; Correlation analysis between sample and standard sample library was carried out by spectral angle matching SAM and Pearson correlation coefficient. Anthracite samples, bituminous coal samples, sandstone samples and limestone samples had a high matching degree under SAM matching model. The cosine angle was above 0.9 at each dust concentration; Correlation coefficient matching model matching degree was strongly affected by dust, and the average correlation coefficient was 0.73; After the experimental standard database and special envoy samples were normal preprocessed by SG convolution and SNV standard, the matching degree of SAM matching model did not change significantly. Correlation coefficient matching model matching degree was significantly improved, the average correlation coefficient was 0. 78; The correlation coefficient matching model excepted for lignite No.2, the spectral correlation coefficient of all samples increased by 0.13, anthracite No.2 The sample correlation coefficient increased by 76.3%, while the spectral correlation coefficient of sample 12 lignite No.2 was reduced by spectral pretreatment. The spectral angle matching SAM and Pearson correlation coefficient coal and rock identification model was established. The two models were used to identify coal samples under different concentrations and binarized coal rock sample, the coals were “0”, and the rocks were “1”. Coal rock identification was performed on 6 experimental samples at different concentrations by two recognition models. The identification accuracy of SAM was 100%, and the recognition time was 8 ms. Pearson correlation recognition accuracy of the coefficient P was 87.5%, and the recognition time was 852 ms.
2020 Vol. 40 (11): 3430-3437 [Abstract] ( 185 ) RICH HTML PDF (7432 KB)  ( 59 )
3438 Verification of Signal Extraction Capability of Near-Infrared Non-Invasive Blood Glucose Detection System
KONG Dan-dan, HAN Tong-shuai, GE Qing, CHEN Wen-liang, LIU Rong, LI Chen-xi, XU Ke-xin*
DOI: 10.3964/j.issn.1000-0593(2020)11-3438-05
Near-infrared non-invasive blood glucose detection technology still fails to meet the accuracy required for clinical application. The main reason on the one hand is that the human blood glucose signal is weak, and the near-infrared absorption band of some components in blood overlaps with the absorption band of glucose. Multivariate regression methods such as partial least squares (PLS) are usually used to extract the glucose concentration information from spectral data. On the other hand, in the measurement process, background interference such as light source drift and measurement condition changes is inevitable. The impact of background interference on the measurement is often stronger than the spectral response caused by the changes in blood glucose concentration. Therefore, these background disturbances must be effectively controlled and eliminated before establishing the blood glucose prediction model. Otherwise, there will likely be pseudo correlations exiting in the blood glucose prediction model established by a multivariate regression method. Therefore, in order to non-invasively detect the blood glucose signal even better, the measurement system itself should have high blood glucose detection capability, and under the premise of keeping the measurement conditions as stable as possible, appropriate data processing methods should be used to eliminate most of the background interference. To this end, this paper evaluated the blood glucose detection capability of the self-developed non-invasive blood glucose detection system, proved that the system could achieve high detection accuracy. Then oral glucose tolerance test (OGTT) and oral water tolerance test (OWTT) were performed on three healthy subjects, and the spectral data of OGTT and OWTT at two different source-detector distances were compared, and the analysis results showed that the variance of the OGTT absorbance change was much larger than the OWTT under the two source-detector distances, and the wavelength distribution characteristic of the absorbance change’s variance for the three subjects varied greatly. Then the spectra data from the two source-detector distances was differentially processed, and the differential spectral data were compared. The analysis results indicated that the variance of OGTT differential absorbance change was far larger than that of OWTT, and the wavelength distribution characteristics of differential absorbance change’s variance for the three subjects were consistent with the absorption characteristic of glucose solution, which proved that the self-developed non-invasive blood glucose detection system combining the differential processing method could effectively eliminate the background interference and extract the signal of blood glucose.
2020 Vol. 40 (11): 3438-3442 [Abstract] ( 146 ) RICH HTML PDF (1945 KB)  ( 59 )
3443 Application Research of Normalization Algorithm Based on EWMA-PCA in Standardization of Water Quality Spectral Data
ZHOU Si-han1,2, HU Xin-yu1,2, TANG Bin1,2,3*, ZHAO Ming-fu1,2, LI Feng-xiao1,2, WANG Ren-jie1,2, XIAO Qi-sen1,2, XIAO Yu1,2
DOI: 10.3964/j.issn.1000-0593(2020)11-3443-08
Model transfer is important for solving the inconsistency of measurement signals due to differences in sample and instrument response functions, and an effective method for solving model transfer is the instrument or data standardization. For the existing spectral standardization methods, there are few applied research on UV-visible absorption spectrum, and the UV-visible spectroscopy water quality multi-parameter detection spectrum detection unit has inconsistent resolution, accuracy, and response range, which is difficult to perform between different instruments. The problem of the comparison of test data and the fitting of multi-parameter data, this paper proposes to use the EWMA-PCA normalization algorithm to achieve the model transfer of UV-visible water quality spectra on different instruments’ (Exponentially Weighted Moving-Average) is an exponentially weighted average moving algorithm for finding phylogenetic trees with a high probability of generating UV-Visible water spectral data and recovering theoretical UV-visible water quality spectral data with maximum probability. The UV-Vis spectral characteristics are not lost or offset, reducing the impact of data processing on the UV-visible water spectral data. In this experiment, different concentrations of potassium hydrogen phthalate solution were used to compare and test the Japanese Hamamatsu C10082CAH spectrometer, the US Ocean Optics Maya2000Pro spectrometer and the Xiamen Optosky ATP2000 spectrometer. In the comparison group 1, the source machine Hamamatsu C10082CAH spectrometer and the target machine ocean Maya2000Pro spectrometer were selected, the comparison group 2 selected the source machine Hamamatsu C10082CAH spectrometer and the target machine Optosky ATP2000 spectrometer, and the comparison group 3 selected the source machine marine Maya2000Pro spectrometer and the target machine Optosky ATP2000 spectrometer. The experimental results of three sets of experiments show that the algorithm can be applied to different ratiometric spectrometers. After the EWMA-PCA normalization algorithm is used to standardize the water absorption spectrum data, the correlation coefficient reaches 99.576 5%, and the variance reaches 0.082 3%, and the peak offset can be reduced to 0.000 5%. Based on the EWMA-PCA normalized spectral normalization algorithm, it has wide adaptability, less need to transfer samples, and high transmission precision. The research results are widely used in spectroscopy water quality testing instruments. It has important theoretical guiding significance and reference value for engineering application.
2020 Vol. 40 (11): 3443-3450 [Abstract] ( 161 ) RICH HTML PDF (5220 KB)  ( 68 )
3451 Wavelength Selection of Near-Infrared Spectra Based on Improved SiPLS-Random Frog Algorithm
CHENG Jie-hong1, CHEN Zheng-guang1,2*
DOI: 10.3964/j.issn.1000-0593(2020)11-3451-06
In the modeling and prediction analysis of near-infrared spectroscopy, the redundancy and collinearity of the data will seriously affect the prediction accuracy and robustness of the model. The feature wavelength selection is an effective method to improve the prediction accuracy of quantitative analysis. Random frog (RF) is a feature wavelength selection algorithm based on different variables with different probability of being selected. In recent years, it has shown good performance in feature wavelength selection. The method calculates the probability of each variable being selected by iteration, and takes the variable with high probability as the feature wavelength. However, the initial variable set V0 of RF is random and uncertain. It may contain useless or disturbing information. Moreover, it is difficult to guarantee the validity of the initial information, which makes the number of iterations too large and the running time too long. In this paper, an improved Si-RF feature wavelength selection algorithm is proposed based on RF. SiPLS is used to select the variables of the full spectrum. At this time, the wavelength obtained is the most sensitive to the change of the target variable. It is used as the initial variable subset of RF to solve the problem of long running time and low efficiency. On the other hand, when RF selects the feature wavelength, it selects the variable whose probability value is larger than the threshold value as the feature wavelength. However, there is no theoretical basis for setting the threshold value, which is easily influenced by human factors. In this paper, the MLR model is established by adding one variable each time in the descending order according to the probability values of being selected of each variable. The subset of variables with the lowest RMSEV value is taken as the feature wavelength, so as to find the wavelength subset contained in the highest prediction accuracy and improve the prediction accuracy. In view of the above two points, Si-RF was applied to soil near-infrared spectroscopy data sets. MLR model is established after selecting the feature wavelength, and the prediction accuracy was compared with that of RF-MLR and Full-PLSR models. The results show that the RF after 10 000 iterations, 10 wavelength points are selected, and the RMSEP of the MLR model is 1.627 6. The improved Si-RF only needs 1 000 iterations to select 17 wavelength points. The RMSEP of MLR model is reduced to 0.818 4, which greatly improves the prediction accuracy and the running efficiency. Compared with the full spectrum, it also greatly improves the prediction accuracy, simplifies the complexity of the model. It proves that improved Si-RF is an effective feature wavelength selection algorithm.
2020 Vol. 40 (11): 3451-3456 [Abstract] ( 240 ) RICH HTML PDF (2540 KB)  ( 78 )
3457 Raman Spectrum Wavelength Selection Method Based on Neural Network
SHEN Dong-xu, HONG Ming-jian*, DONG Jia-lin
DOI: 10.3964/j.issn.1000-0593(2020)11-3457-06
Blood identification is crucial for the field of inspection and quarantine, criminal investigation and animal protection. Traditional blood identification methods have shortcomings such as long analysis period and damaging to blood samples during the identification process. Raman spectroscopy can obtain molecular vibration and rotation information by analyzing the scattering spectrum different from the incident light frequency, and obtain the composition of the material. Moreover, it has the characteristics of zero pollution and non-contact, which provides the possibility of non-destructive identification of blood. However, there is serious multicollinearity between each wavelength point in Raman spectrum, and directing the use of full-spectrum for modeling will increase the complexity of the model and reduce the stability of the model. According to the characteristics of Raman spectroscopy, this paper proposes a wavelength selection based on neural network. The method uses the neural network to learn the contribution weight of each wavelength point to the correction model, and uses the mean value of the weight as the threshold value to remove the wavelength point whose weight is lower than the threshold value, so as to achieve the purpose of wavelength selection. In order to make it easier to determine the threshold of the screening, sparse constraints are added to the weight learning process, which greatly reduces the wavelength points used for screening. The proposed method was validated by Raman spectroscopy datasets of animal and human serum. The experimental results show that the model established by the wavelength selection using this method has a certain improvement in classification accuracy compared and AUC value with the full spectrum, the accuracy of artificial neural network (NN) reached 94.495% and AUC value reached 0.985 0. The accuracy of PLS-DA reached 92.661%, and AUC value reached 0.976 0. Compared with the traditional wavelength selection method UVE, the method selects fewer wavelength points, and only 42 wavelength points have been selected for modeling, the classification accuracy of the calibration model and AUC value is high, and accuracy reached 92.661%, and AUC value reached 0.976 0. It is proved that the wavelength selection method can effectively screen out the wavelength points contributing to the modeling, which provide a possibility for non-destructive identification of blood, which has certain practical value.
2020 Vol. 40 (11): 3457-3462 [Abstract] ( 206 ) RICH HTML PDF (3384 KB)  ( 93 )
3463 An Improved Algorithm for Adaptive Infrared Image Enhancement Based on Guided Filtering
WANG Zi-jun1, 2, LUO Yuan-yi1, 2*, JIANG Shang-zhi1, 2, XIONG Nan-fei1, 2, WAN Li-tao1, 2
DOI: 10.3964/j.issn.1000-0593(2020)11-3463-05
Detail enhancement and noise suppression are particularly important in infrared image processing, and the focus is to compress the infrared from the high to the low dynamic range while preserving details and suppressing noise. In this study, with an improved adaptive detail enhancement algorithm for infrared images based on guided filtering (AGF&DDE) as the foundation, an improved algorithm for adaptive infrared image enhancement based on guided filtering was proposed. The input image was smoothed by a guided image filter and separated into a base layer image and a detail layer image that contained large and small dynamic temperature information, respectively. Then, the base layer image and the detail layer image were compressed, noise-suppressed and finally fused with different fusion ratios to form the output image. To shorten the algorithm operation time, we highlighted the image detail information while suppressing the noise of the detail layer. The adaptive threshold parameters that can be used to screen effective gray values through the maximum and minimum values of histogram distribution information were determined, and used together with histogram distribution to design a one-dimensional compression array. The grayscale value of each pixel in the 16 bit base layer image was mapped to a range of 8bit according to the array. The effective number of grey value in the histogram was estimated, and the image scene information was judged by the ratio between the number of effective gray values to the total number of gray values. According to the different scenarios, The adaptive fusion ratio was determined, and the base layer image and the detail layer image were fused with different scale coefficients to form an 8bit output image. The experimental results were compared with the histogram equalization algorithm, the high-dynamic infrared image enhancement algorithm based on guided filtering, and the adaptive infrared image enhancement algorithm based on guided filtering. Four different scenarios were selected for analysis from subjective and objective levels. The comparison showed the image processed by this algorithm could highlight the detail contour information, reduce the influence of detail noise on the fused output image, and present a better visual effect. According to the objective evaluation, the average computing time of this algorithm in four scenarios was 0.753 5 s, which was lower compared with other algorithms. Moreover, the fusion ratio coefficient of the base layer image and the detail layer image achieved the effect of the adaptive scene.
2020 Vol. 40 (11): 3463-3467 [Abstract] ( 250 ) RICH HTML PDF (2967 KB)  ( 76 )
3468 The Fluorescence Spectra of Gem-Quality Hauyne
LÜ Fang-lin, Andy Hsitien Shen*
DOI: 10.3964/j.issn.1000-0593(2020)11-3468-04
Blue hauyne from the Eiffel District, Germany, which belongs to sodalite group mineralogically, is among the rarest gem species. Some crystals represent characteristic orange fluorescence, but few details in its fluorescence spectra were found in the literature. In this paper, more than 20 gem-quality hauyne samples from this region were collected and tested. This batch of hauyne shows body color differing from pale grayish blue to dark blue. Orange fluorescence is only visible under long-wave ultraviolet light (365 nm), while inert under short-wave ultraviolet light (254 nm). Fluorescence spectrometer was applied to describe the photoluminescence phenomenon of samples. A series of fluorescence spectra were collected, including 3D ones. Results showed that the emission band of samples with orange fluorescence centered at 566 and 425 nm. The 566 band, which determines the fluorescence color of the sample, can be excited by light of wavelength range of 300~500 nm, and the optimal excitation wavelength is 397 nm. Furthermore, the 350 nm band can be excited by the 260~325 nm range ultraviolet light, with a best excitation wavelength of 310 nm. High-resolution emission spectrum under 397 nm showed that 566 nm band is accompanied by a large number of stepped fluorescence peak shoulder, which centers at 581, 600, 621, 642, 666 nm respectively. The energy differential of adjacent shoulders is about 0.07 eV. It was observed that the intensity of orange fluorescence was negatively correlated with the depth of blue of the samples, that is, the lighter the blue was, the stronger the orange fluorescence of the sample was. Therefore, it was speculated that the fluorescence peak at 566 nm and its subsequent acromion were related to chromophore S-2.
2020 Vol. 40 (11): 3468-3471 [Abstract] ( 205 ) RICH HTML PDF (2050 KB)  ( 93 )
3472 Fluorescence Spectral Characteristics of Soil Dissolved Organic Matter in Different Plant Formations After Reverting Farmland to Wetland
SHI Chuan-qi1,2, LI Yan3, YU Shao-peng2, HU Bao-zhong1,2*, JIN Liang4
DOI: 10.3964/j.issn.1000-0593(2020)11-3472-05
The peak position and intensity of three-dimensional fluorescence spectroscopy can be used to characterize the type and concentration of fluorescent substances, which is widely used in the study on dissolved organic matter (DOM) properties. In order to study the soil characteristics of different plant formations and guide the work of reverting farmland to wetland, the surface soil of six typical plant formations of Ulmus pumila, Salix sungkianica, Artemisia scoparia, Phragmites australis, Carex appendiculata, and Typha Orientalis were collected in this study, and the fluorescence spectroscopy of soil DOM was determined, the source and composition of soil DOM of the six plant formations were analyzed by three-dimensional fluorescence spectroscopy with parallel factor analysis method. Combined with physiochemical soil indexes, the influencing factors of soil DOM organic components were further analyzed. The results showed that there was no significant difference in the humification index of the six plant formations, the humification degree of the hygrophyte Phragmites australis formation was significantly higher than that of the xerophyte Artemisia scoparia formation. The fluorescence index of soil DOM was between the terrestrial eigenvalue (1.4) and the autochthonous eigenvalue (1.9), indicating that the source of soil DOM was not only generated by microbial activities, but also by the input of plant litter and root exudates. The fluorescence index and biological index of the soil in the Carex appendiculata formation and the Typha orientalis formation were relatively high, which indicated that the two formations had relatively strong autochthonous characteristics, while the terrestrial characteristics of the Phragmites australis formation and the Artemisia scoparia formation were relatively high. Three organic components, fulvic-acid-like component (C1), humic-acid-like component (C2) and protein-like component (C3), were identified from soil DOM of the six plant formations. The soil DOM relative concentration of Phragmites australis formation was higher than that of Typha orientalis formation, and that of Carex appendiculata formation was lower. Excepting for the Phragmites australis formation, C3 accounted for a relatively high proportion in the soil of each plant formation, followed by C1 and C2, which reflected that the surface soil DOM was relatively rich in small molecular substances, and indicated that the degree of humification was not high. There was no significant difference in soil pH value among different plant formations. The dry environment had higher soil bulk density, while the wet environment had higher soil water content and cation exchange capacity. The contents of soil total organic carbon, total N, total P and total K in woody plant formation were higher than those in herbaceous plant formation. Soil bulk density, water content and cation exchange capacity could significantly affect the soil DOM organic component structure. Therefore, increasing the area of hygrophyte herbage in the process of reverting farmland to a wetland can improve the degree of soil humification to a certain extent.
2020 Vol. 40 (11): 3472-3476 [Abstract] ( 188 ) RICH HTML PDF (1198 KB)  ( 44 )
3477 Detection of Protease Deterioration Factor in Tomato by Fluorescence Sensor Array
LI Meng-yao1, 2, WANG Shu-ya1, XIE Yun-feng1, LIU Yun-guo3*, ZHAI Chen1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3477-06
Based on fluorescence spectroscopy, combined with immunofluorescence and fluorescence probe, a fluorescence sensor array detection technology of tomato protease deterioration factor was established. In this study, a quantum dot fluorescent probe capable of being recognized by pectinase, catalase and superoxide dismutase antibodies was synthesized by carbodiimide method. Immunofluorescence analysis of pectinase, catalase and superoxide dismutase was established based on the principle of antigen-antibody specific recognition, and the influence of its reaction parameters was investigated. Under the optimized reaction conditions (60-min reaction time at 37 ℃), the immunofluorescence intensity presented excellent linearity with the activities of pectinase, catalase and superoxide dismutase by studying the corresponding fluorescence spectrum changes. The detection range of activity was 0.05~500,0.02~800 and 0.5~900 U·mL-1, respectively. The correlation coefficients were 0.989 4, 0.993 8, 0.981 9, and the detection limits were 5.0×10-3, 2.0×10-3, 5.0×10-2 U·mL-1, respectively. Compared with the existing analysis method, the method is simple in operation, low detection line and linear range. Based on the near-infrared fluorescent probe method, a novel hydrosoluble near-Infrared fluorescence off-on probe has been developed for detecting carboxylesterase and polyphenol oxidase activities. The probe was designed by introducing (4-acetoxybenzyl)oxy and 3-hydroxybenzyloxy respectively as quenching and recognizing moiety to the decomposed product of IR-783, which exhibits excellent near-infrared fluorescence feature and good water solubility. The responding mechanism of the novel probe to carboxylesterase and polyphenol oxidase was investigated. By studying the corresponding fluorescence spectrum changes at 37 ℃ pH 7.4, it was found that the presence of carboxylesterase and polyphenol oxidase will cut off the bonds that connect the fluorophore with a recognition moiety in the probe, resulting in the release of the fluorophore, which achieves the purpose of detecting carboxylesterase and polyphenol oxidase. Moreover, the release amount of the fluorophore is linearly related to the activity of carboxylesterase (0.01~0.3 U·mL-1) and polyphenol oxidase (10~70 U·mL-1). This behaviour leads to the development of a simple and sensitive fluorescent method for assaying carboxylesterase and polyphenol oxidase activity, with detection limits of 3.4×10-3 and 1.1×10-2 U·mL-1, respectively. The correlation coefficients were 0.997 2 and 0.991 0, respectively. Compared with the existing near-infrared fluorescent probe method, the near-infrared fluorescent probe synthesized in this study has better water solubility and higher specificity. The research realized the one-time and visual array detection of various enzyme activities in the sample, which is based on the multi-function fluorescent microplate reader to set the corresponding excitation wavelength and emission wavelength for different fluorescent substances. Through the sample spike recovery experiment, it is found that the recovery rate of the method is within the range of 90.0%~102.3%, the coefficient of variation is <15%, and it has good specificity, which indicated that the method established in this study has good accuracy and is expected to be applied.
2020 Vol. 40 (11): 3477-3482 [Abstract] ( 140 ) RICH HTML PDF (2474 KB)  ( 48 )
3483 Interaction Between Three Sulfur-Containing Amino Acids in Garlic and Bovine Serum Albumin Determined by Fluorescence Spectrometry
LI Xing-xing, ZHANG Xiang, HUANG Xue-song*
DOI: 10.3964/j.issn.1000-0593(2020)11-3483-06
Sulfur-containing amino acids (SAA) such as S-allyl cysteine (SAC), S-allyl cysteine sulfoxide (SACS), and S-allyl mercapto cysteine (SAMC) from garlic (Allium sativum L.) have many bioactivities like anti-tumor, antioxidant and so on. These bioactivities should be directly related to the interaction between the above-mentioned SAA and biomacromolecules such as proteins in organisms. In order to elucidate the relationship, the modle system was made of by bovine serum albumin (BSA) and SAA. The interaction between SAC, SACS or SAMC and BSA was investigated in Tris-HCl buffer solution at pH 7.40 by fluorescence spectroscopy (FS) and ultraviolet absorption spectroscopy (UVS). FS was determined by scanning from 300 to 400 nm at 280 nm excitation wavelength. And UVS was determined by scanning the SAMC solution from 300 to 400 nm. FS and UVS results show that the quenching type of BSA with SAC or SACS is dynamic quenching, and the one of BSA and SAMC is static quenching. The binding constants of BSA and SAMC solution at 298 K and 310 K are 6.18×103 and 5.54×103 L·mol-1, respectively, with strong binding effect. The number of the binding site of BSA and SAMC at above temperature is approximating to 1, i.e. forming a 1∶1 complex, which can be deduced that SAMC is well stored and transported in organisms. The binding distance between BSA and SAMC is 1.61 nm. The binding ΔG of BSA and SAMC is -21.63 and -22.21 kJ·mol-1 at 298 and 310 K, respectively, indicating that the reaction is a spontaneous process. The binding ΔH is about -7.06 kJ·mol-1 at the checking temperature; the binding ΔS of BSA and SAMC is 48.89, 46.99 J·mol-1·K-1 at 298 K and 310 K, respectively. The electrostatic attraction is dominated between BSA and SAMC, based on their ΔH and ΔS. It could be concluded that SAMC has a strong binding with BSA, which provides a theoretical basis for SAMC as a drug molecule. At the same time, these results also provide a theoretical basis for further study of the interaction, development and utilization SAA and other macromolecules.
2020 Vol. 40 (11): 3483-3488 [Abstract] ( 167 ) RICH HTML PDF (2796 KB)  ( 55 )
3489 Detection of I- in Water by the Hg2+@CDs Fluorescent Sensor
YE Jia-wen1, CHANG Jing-jing1*, GENG Yi-jia2, CUI Yuan1*, XU Shu-ping2, XU Wei-qing2, CHEN Qi-dan3
DOI: 10.3964/j.issn.1000-0593(2020)11-3489-05
In the human body, iodine is the key raw material for thyroid hormone. Moreover, thyroid hormone had a critical role in human growth and development and regulated metabolism, so iodine was played a vital role in the normal operation of the human body. The iodine was mainly in the form of iodinated amino acids presented in the thyroid gland. Furthermore, many methods were used to detect I- with high precision and accuracy. However, most of the approaches lie in complicated operations and high detection cost. Therefore, it is of great significance to develop a method for detecting I- with low cost, fast, accuracy and simple operation. In this study, a simple and convenient fluorescence “Off-On” detection method was used for I- testing in solution. The carbon nanodots (CDs) were synthesized by a simple hydrothermal method, which citric acid and ethane diamine were used as the carbon source and the nitrogen source. The optical properties of the CDs were characterized by a fluorescence spectrometer and an ultraviolet-visible spectrometer, which emitted bright blue light at an excitation wavelength of 350 nm. Additionally, the groups on the surface of the CDs were characterized by the Fourier-infrared spectroscopy and high resolution ultraviolet photoelectron spectroscopy. The fluorescence of the prepared CDs can be pre-quenched by Hg2+. And the fluorescence quenching may be due to the non-radiative electron-transfer from the excited states to the d orbital of Hg2+. Another possible explanation is attributed to the Hg2+ ions combine with a large amount of nitrogen on the surface of the CDs to form a non-fluorescent complex, which leads to fluorescence quenching of CDs. The optimal concentration condition of Hg2+ was selected by analyzing the fluorescence spectrum of CDs solution with different concentration Hg2+. Once they meet I- in the solution, Hg2+ on the surface of the CDs will be released due to the strong interaction between Hg2+ and I-, and the fluorescence of CDs can be restored. Thus, I- in the solution can be detectable by this fluorescent “Off-On” method, and the detection range is 5.0~75 μmol·L-1 with the detection limit of 0.25 μmol·L-1. Finally, the selectivity and anti-interference ability of Hg2+@CDs fluorescence sensing system were analyzed by fluorescence spectrum. And the results showed that the fluorescence sensing system had high selectivity to I- and good ion anti-interference performance.
2020 Vol. 40 (11): 3489-3493 [Abstract] ( 147 ) RICH HTML PDF (2406 KB)  ( 45 )
3494 Comparisons and Applications of Functional Equations for the Calculation of the Protein-Ligand Binding Constant Based on Fluorescence Spectral Data
ZHANG Jing1, GAO Xuan1, 2, JIN Liang1, WANG Hong-hui1, ZHOU Xi-ping1
DOI: 10.3964/j.issn.1000-0593(2020)11-3494-05
The binding interactions of proteins with ligands play important roles in the physiological and biochemical processes of organisms. Thus it is a research hotspot in many fields. A key objective of the investigations on Protein-Ligand binding is to obtain their binding constant (Kb) for evaluating the strength of their binding. Fluorescence spectroscopy is widely used in Protein-Ligand binding studies as its high sensitivity, convenience, rapidity and low cost. When applying fluorescence spectroscopy, it is a key step to obtain the Kb value through mathematical analysis of fluorescence data with the aid of a functional equation. However, due to the different application range of different equations, the Kb values obtained by different equations for the same system are often varied. This work discussed the derivation process and the application conditions of the functional equations for calculating the Kb value of Protein-Ligand binding using fluorescence spectral data. Based on this, we summarized the optimal equation for the calculation of the Kb value for Protein-Ligand binding modes of 1∶1 and 1∶n (n≥2) under different preconditions. The discussion suggested that the selection of the optimal equation is based on two preconditions: a: Whether the Protein-Ligand complex is fluorescent; b: Whether the ligand concentration is much higher than the protein concentration. On the other hand, the human serum albumin (HSA)-Norfloxacin (NFX) binding system was used as a model, and the difference of the Kb values obtained by the fitting of different functional equations was compared and the corresponding reasons were analyzed. The results showed that HSA bound with NFX in 1∶1 mode, and the Kb value was calculated to be 5.0×104 L·mol-1 at 298 K using the most appropriate equation (S12) for this system. However, the Kb values obtained by equation (S6) and (S24) were 28.8% and 48.6% higher than that by equation (S12) respectively, and the value obtained by equation (S17) was about two orders of magnitude higher. This intuitively showed the effect of choosing the inapplicable equation on the final result. In addition, the Kb value obtained by fluorescence spectroscopy in the present work was compared with those obtained by other techniques, indicating the relative reliability of fluorescence spectroscopy for the calculation of the Kb value in Protein-Ligand binding, and also pointing out the limitations of this method. This work warns us that when obtaining the Kb value of Protein-Ligand binding using fluorescence spectral data, it is very necessary to select the most suitable functional equation according to the preconditions (i.e. whether the hypothesis a and/or b are true or not), which will determine the reliability of the obtained results.
2020 Vol. 40 (11): 3494-3498 [Abstract] ( 262 ) RICH HTML PDF (1225 KB)  ( 78 )
3499 Analyzing Errors due to Measurement Positions and Sampling Locations for In Situ Measurements of Soil Organic Matter Using Vis-NIR Spectroscopy
ZHANG Hao-dan1,SUN Xiao-lin1, 2*,WANG Xiao-qing1,WANG Hui-li3
DOI: 10.3964/j.issn.1000-0593(2020)11-3499-09
Due to the heterogeneity of soil, there are spectral differences between different measurement positions of a soil sample and among different samples of a soil genetic layer. As a result, an estimated value of a soil property using in situ spectra of soil inevitably has errors. However, these errors have not been revealed so far. In this paper, 80 soil profiles and 38 soil surface samples were collected twice with cutting ring from a small area of woodland in typical hilly areas in southern China. Then, the soil organic matter content was measured by in-situ spectrometry and traditional laboratory method, so as to analyze the estimation error of soil organic matter content caused by different spectral test points and sampling locations. The results show that, the spectral difference of each sample at a total of 18 test points ranges from 0.12° to 8.13°, with an average value of 1.55°. The spectral difference between two repeated sampling locations of each sample is 0.18°~3.65°, with an average value of 0.88°. The estimated error of soil organic matter due to the different positions of test points was 0.92~14.66 g·kg-1, accounting for 3.8%~428% of the measured organic matter content. The estimation error of soil organic matter caused by different sampling locations is 0.005 7~11.46 g·kg-1, accounting for 0.017%~92% of the measured organic matter. Moreover, the error caused by the former is larger than that caused by the partial least squares regression model used in this paper, while the error caused by the latter is slightly smaller than that caused by this model. In addition, it is found that these two errors increase with the increase of measured organic matter content. Hence, this paper argues that the errors caused by different test points and sampling locations should be paid attention to in future studies, especially in soils with higher organic matter content, and calls for research on more effective methods to reduce these errors.
2020 Vol. 40 (11): 3499-3507 [Abstract] ( 220 ) RICH HTML PDF (4227 KB)  ( 78 )
3508 Effect of Near Infrared Hyperspectral Imaging Scanning Speed on Prediction of Water Content in Arabidopsis
LÜ Meng-qi1, SONG Yu-jie4, WENG Hai-yong1, 3, SUN Da-wei1, 3, DONG Xiao-ya2, FANG Hui1, 3, CEN Hai-yan1, 3*
DOI: 10.3964/j.issn.1000-0593(2020)11-3508-07
Hyperspectral imaging technology can non-destructively detect physicochemical information of plants with different dimensions. Existing researches often focus on analyzing the average spectrum of hyperspectral images, ignoring the information of their spatial dimensions. In this study, the model plant Arabidopsis thaliana was used as the research object to explore the influence of spatial resolution difference caused by different scanning speeds of hyperspectral imaging on the measurement of plant canopy moisture content, and to provide optimization for rapid online detection of plant canopy moisture content by hyperspectral imaging program. An open-line hyperspectral image of the Arabidopsis canopy was extracted using an indoor online hyperspectral imaging system at 20, 30 and 40 mm·s-1, and the average of the Arabidopsis thaliana canopy reflectance spectrum was extracted. Secondly, the quantitative analysis model of canopy water content and the average reflectance spectrum of Arabidopsis thaliana was established by Partial Least Squares Regression (PLSR). The determination coefficient (R2), root mean square error (root), mean squared error (RMSE) and relative variance deviation (RPD) were used to evaluate the model. The PLSR model based on pre-processing spectra such as the original spectrum, Multiplicative Scatter Correction (MSC) algorithm and Savitsky-Golay smoothing algorithm is compared. The best spectral pre-processing method is selected for subsequent data processing. Finally, the successive projections algorithm (SPA) is used to analyze and compare the prediction accuracy based on the optimal feature wavelength and the full wavelength, and to determine the influence of the hyperspectral image scanning speed on the canopy water content prediction of Arabidopsis thaliana. The results show that when the scanning speed was increased from 20 to 30 mm·s-1, the full-band PLSR model based on MSC pretreatment predicted that the coefficient of canopy moisture content in Arabidopsis was reduced by 0.88%, less than 1%. When the scanning speed was increased from 20 to 40 mm·s-1, the coefficient of determination of canopy water content in Arabidopsis was reduced by 2.3%. It shows that while the scanning speed is properly increased, the high water content prediction accuracy of the plant canopy can be ensured. Changing the hyperspectral scanning speed can more effectively utilize the spatial information of the hyperspectral image space. After the scanning speed is appropriately increased, the spatial dimension information of the hyperspectral image changes, improving the image collection efficiency of the actual production application and reducing the data processing time.
2020 Vol. 40 (11): 3508-3514 [Abstract] ( 182 ) RICH HTML PDF (3123 KB)  ( 88 )
3515 Fast Prediction Method of Thermal Aging Time and Furfural Content of Insulating Oil Based on Near-Infrared Spectroscopy
JIANG You-lie, ZHU Shi-ping*, TANG Chao, SUN Bi-yun, WANG Liang
DOI: 10.3964/j.issn.1000-0593(2020)11-3515-07
Accurate assessment of transformer oil-paper insulating thermal aging serves as an important part to ensure the safe operation of power equipment. The successful application of Near Infrared Spectroscopy in petrochemicals and other fields provides new ideas for electrical insulation testing. The accelerated thermal aging test has experimented in a vacuum environment of 130 ℃. Fourteen groups of samples with different aging time are prepared. The spectrum of the aged insulating oil was collected by the Near Infrared Spectroscopy, and the furfural content in transformer oil was detected by high performance liquid chromatography(HPLC). There are obvious absorption peaks at 8 373, 8 264, 7 181, 7 076, 6 981, 5 855, 5 799, and 5 678 cm-1 in the original spectrum. This study specifically analyzes the attribution of each absorption peak. The original spectrum was preprocessed using a five-point cubic polynomial Savitzky-Golay convolution smoothing algorithm. The characteristic spectral regions for aging time are selected as 11 209~10 364, 9 087~7 818, 7 390~4 424 cm-1, with a total of 1 320 wavelength points. At the same time, the spectral information of the characteristic region is extracted by PCA, which indicates that the cumulative contribution rate of the first seven principal components is 99.78%. On the basis of the above, a PCR, PLSR, PCA-BP-ANN prediction model for aging time was established. It is shown that the PCA-BP-ANN aging time prediction model with conjugate gradient algorithm is the best, with RMSEP of 18.67 and R2 of 0.997 3. The characteristic spectral region of the furfural content in the oil is selected from 9 107 to 4 424 cm-1 for a total of 1210 wavelength points. At the same time, the spectral information of the characteristic region is extracted by PCA, which indicates that the cumulative contribution rate of the first four principal components is 99.96%. On the basis of the above, a PCR, PLSR, PCA-BP-ANN prediction model for the content of furfural in oil was established. It is shown that the PCA-BP-ANN furfural content prediction model with conjugate gradient algorithm performs best, with RMSEP of 0.134 4 and R2 of 0.987 7. It is feasible to evaluate the thermal aging time and the furfural content based on near-infrared spectroscopy of insulating oil.
2020 Vol. 40 (11): 3515-3521 [Abstract] ( 203 ) RICH HTML PDF (4498 KB)  ( 57 )
3522 Evaluation and Modifying of Multispectral Drought Severity Index
LIU Jun1, 2, 3, LIANG Shao-qing3, LI Yan-rong3, QIN Rong-rong3, ZHANG Tao-ran3, YANG Qiang3, DU Ling-tong4
DOI: 10.3964/j.issn.1000-0593(2020)11-3522-08
Drought is a very destructive natural disaster. In recent years, affected by climate change, the frequency of drought is increasing all over the world, causing serious economic losses. Accurate monitoring of drought information is the basis of disaster prevention and reduction. Drought Severity Index (DSI) is a kind of index that can effectively capture regional drought information. It has been proved that it has great potential in global drought monitoring, but its classification of drought grade is obviously regional. In order to test the applicability of DSI on the provincial scale and correct the classification differences, DSIMODIS and DSIAVHRR from 2001 to 2014 were obtained based on the data sets of MODIS ET/PET, NDVI and AVHRR NDVI in Shanxi Province. Meanwhile, combined with SPEI, the spatial and temporal distribution of drought in these three indexes was compared and analyzed. To verify the reliability of SPEI, long time series SPEIs were compared with historical drought records. In order to investigate the errors of DSI in the region, DSIMODIS, DSIAVHRR and SPEI were compared in time frequency and spatial distribution. Finally, as SPEI a reference and based on the original DSI classification standard, the new drought classification standard was obtained by adjusting the threshold of drought grade of DSIMODIS with 0.1 as the step size. In addition, DSIMM was used to monitor the provincial seasonal scale from 2001 to 2014, to capture the typical drought events in 2001 and 2002, and to verify the applicability and robustness of DSIMM in drought monitoring in Shanxi. Studies show that there is a high correlation between DSIMODIS and DSIAVHRR, with a correlation coefficient of 0.75. Both of them have consistent performance in spatial distribution and time frequency of drought, indicating that DSI can be extended to AVHRR data set in the absence of data to make up for the deficiency of MODIS data in long time series monitoring. D1 was underestimated by DSIMODIS, while D2, D3 and D4 were overestimated in Shanxi province. In the four grades of mild drought D1, moderate drought D2, severe drought D3 and extreme drought D4, DSIMM and SPEI showed a high degree of consistency in the occurrence frequency and spatial ratio of drought. The time frequency of D3 was completely consistent, and the spatial distribution consistency of D4 was 0.98. The drought classification standard of DSIMM can monitor the drought information at different temporal and spatial scale accurately, which can be applied to the whole governor time series drought monitoring. The results can be used for reference in regional scale drought monitoring using DSI, and a simple calculation method with high accuracy is obtained for Shanxi Province drought information monitoring.
2020 Vol. 40 (11): 3522-3529 [Abstract] ( 182 ) RICH HTML PDF (5336 KB)  ( 94 )
3530 Identification of Chilled and Frozen-Thawed Salmon Based on Hyperspectral Imaging Technology
SUN Zong-bao, LIANG Li-ming, LI Jun-kui, ZOU Xiao-bo*, LIU Xiao-yu, WANG Tian-zhen
DOI: 10.3964/j.issn.1000-0593(2020)11-3530-07
Salmon is a kind of marine fish with rich nutrition and delicious taste. In recent years, the consumption market of salmon in China wasin great demand, and the import volume of salmon was increasing. The import methods mainly included chilled salmon and frozen salmon. Compared with frozen salmon, chilled salmon can retain the excellent quality of salmon to a greater extent, but at the same time, it cost more and was more expensive. Therefore, some illegal traders sold frozen-thawed salmon as chilled salmon in order to make more profits. This kind of fraud not only seriously damaged the interests of consumers but also go against the development of salmon market inChina. In order to establish a fast and non-destructive method to detect the quality of salmon, this study took the chilled and frozen-thawed salmon as the research object, used hyperspectral imaging technology to analyze the spectral difference and image texture difference between the chilled and frozen-thawed salmon, and combined the chemometrics method -to identify the chilled and frozen-thawed salmon quickly. In the process of frozen transportation, salmon may be frozen and thawed for many times due to the cold chain conditions and other factors. Therefore, in order to improve the universality of the detection method, salmon with different frozen-thawed times were set as the frozen-thawed group in this study. Firstly, the hyperspectral image data of the samples were collected by the hyperspectral imaging system. Then, ENVI 4.5 software was used to extract the average spectrum of the region of interest in the sample’s hyperspectral image, and the texture information of the first three principal component images was extracted by using the Grey-level co-occurrence matrix(GLCM).The original spectrum was firstly pretreated by multiple scattering correction(MSC), then principal component analysis(PCA), competitive adaptive reweighting algorithm(CARS),successive projections algorithm (SPA) and CARS-SPA were used to reduce the dimension and wavelength of the spectrum. Finally, based on spectral information, image information and fusion spectroscopy-image information, the identification model of chilled and frozen-thawed salmon were established by combining Back-propagation neural network(BPANN), Linear discriminant analysis(LDA), Ultimate learning machine(ELM) and Random forest(RF).The results showed that the CARS-ELM model combined with the MSC preprocessing spectrum had the best recognition effect on the chilled and frozen-thawed salmon, the recognition rates of the calibration set and prediction set were 100.00% and 95.00%, respectively. In addition, the CARS-ELM model based on the preprocessing spectrum of MSC had the best effect on the identification of the times of frozen and thawed of salmon, the recognition rates of the calibration set and prediction set were 97.50% and 91.67%, respectively. And the fast identification of chilled and frozen-thawed salmon based on hyperspectral imaging technology was realized.
2020 Vol. 40 (11): 3530-3536 [Abstract] ( 228 ) RICH HTML PDF (2763 KB)  ( 67 )
3537 Rapid Determination of Canthaxanthin in Egg Yolk by First Order Derivative Spectroscopy
ZHAO Qiu-ling1,3,SHI Ya-jing1,ZHANG Zhen-yu2
DOI: 10.3964/j.issn.1000-0593(2020)11-3537-05
In order to make huge profits, the illegal traders add canthaxanthin to chicken feed to make fake native eggs, which seriously damages the rights and interests of consumers. Both canthaxanthin and yolk coloring (lutein, zeaxanthin and carotene) are linear polyene molecules with similar structures and similar molecular weights; they are extracted at the same time and are difficult to separate. The ultraviolet-visible spectra of canthaxanthin and yolk extract overlap seriously, so it is impossible to detect canthaxanthin by traditional spectroscopy. In this paper, ultraviolet-visible spectrophotometry and first derivative spectrophotometry were combined to establish a rapid method for the determination of canthaxanthin in egg yolk without separation after simple extraction, the interferences of lutein, zeaxanthin and carotene on the detection of canthaxanthin were effectively eliminated. Firstly, the yellow compounds in the yolk were extracted with a mixed solvent of ethanol and chloroform. The spectra of yolk extract and canthaxanthin standard solution were scanned by ultraviolet-visible spectrophotometer. Then the spectra were processed for first-order differential processing by Origin software and were smoothed to eliminate noise by Adjacent-Averaging method. According to the first derivative spectra’ characteristics of yolk extract, standard canthaxanthin sample and their mixture and the zero-cross point position of the first derivative spectrum of yolk extract, 448, 467 and 520~579 nm can be used as detection wavelength of canthaxanthin. The first derivative spectrum value of the mixture of yolk extract and the standard canthaxanthin solutions was plotted against the concentration of canthaxanthin to obtain the straight working line. The linear relationship and detection limit of the working line at 448, 467, 520 and 535 nm wavelengths were investigated. The results showed that the optimal detection wavelength of canthaxanthin was 520 nm. The linear regression equation of the working line at 520 nm was Y=0.001 01C+0.000 180 9 and R2=0.992 9. The linear range was 0~17.68 μg·mL-1, and the detection limit was 0.58 μg·mL-1. In order to verify the effectiveness of this method in actual sample measurement, three egg samples from different producing areas were added and recovered. The results showed that the average recovery of the samples ranged from 96.4% to 102.8%, and the relative standard deviation ranged from 2.53% to 5.67%. The method does not need complicated sample pretreatment steps and large-scale instruments; it is simple, accurate and low cost and can be used to detect canthaxanthin in egg yolk.
2020 Vol. 40 (11): 3537-3541 [Abstract] ( 154 ) RICH HTML PDF (1737 KB)  ( 45 )
3542 Study on Extracting Characteristic Wavelength of Soybean Physiological Information Based on Hyperspectral Technique
LIU Shuang, YU Hai-ye, PIAO Zhao-jia, CHEN Mei-chen, YU Tong, KONG Li-juan, ZHANG Lei, DANG Jing-min, SUI Yuan-yuan*
DOI: 10.3964/j.issn.1000-0593(2020)11-3542-07
The accurate acquisition and prediction of physiological information can provide a basis for the fine management of planting. The traditional soybean physiological information inversion methods have low detection efficiency, cumbersome operation process and mostly damage detection. To this end, this paper uses hyperspectral technology to establish a rapid non-destructive inversion method for soybean physiological information. The leaves of soybean flowering and pod-forming period were taken as research objects, and the hyperspectral, chlorophyll content, net photosynthetic rate and photosynthetically active radiation data were obtained on 2 dates (D1 and D2). First, multiple scatter correction (MSC), standard normal variable transformation (SNV), first derivative (FD), second derivative (SD), Savitzky-Golay smoothing (SG), MSC-SG-FD, MSC-SG-SD, SNV-SG-FD and SNV-SG-SD methods are used to preprocess the original spectral data, then establish a full-band model by partial least squares (PLS), compare and analyze, and select the optimal preprocessing method. The feature wavelengths are filtered and extracted by competitive adaptive reweighted sampling (CARS), successive projections algorithm (SPA) and correlation coefficient (CC), respectively. Finally, the preferred preprocessing method and the characteristic wavelength variable are modeled and compared by PLS. The correlation coefficients Rc and Rp of the correction set and the prediction set are used as model evaluation indexes, and the inversion model with the highest correlation with soybean physiological information is finally selected. The results showed that the Rc and Rp of the full-band PLS model with chlorophyll content established by MSC-SG-FD pretreatment were the highest, 0.909 and 0.882 (D1), 0.909 and 0.880 (D2), respectively, the Rc and Rp of the full-band PLS model with light energy utilization established by SNV-SG-FD pretreatment are the highest, 0.913 and 0.894, 0.902 and 0.869, respectively, which shows the highest model performance characteristics compared with the original and other pre-processed models. Further comparing the modeling of the three characteristic wavelength extraction methods, it is found that the variables selected by the SPA algorithm can compress the modeling variables of the chlorophyll content inversion model from 512 to 20 (D1) and 23 (D2), and the variable compression rate is as high as 96.09% and 95.51%. At the same time, the modeling variables of the light energy utilization inversion model can be compressed to 27 and 37, and the variable compression rate is as high as 94.73% and 92.77%. Finally, the optimal modeling method for inversion of chlorophyll content is MSC-SG-FD-SPA-PLS with Rc values of 0.944 (D1) and 0.941 (D2), Rp values of 0.911 and 0.903, and the optimal modeling method for inversion of light energy utilization is MSC-SG-FD-SPA-PLS with Rc values of 0.929 (D1) and 0.925 (D2), Rp values of 0.912 and 0.907 The model has high precision and can provide technical support for large-area detection of physiological information.
2020 Vol. 40 (11): 3542-3548 [Abstract] ( 209 ) RICH HTML PDF (4208 KB)  ( 93 )
3549 Detection of Component Content Changes During Tofu Formation Based on Hyperspectral Imaging Technology
WANG Cheng-ke, ZHANG Ze-xiang, HUANG Xiao-wei*, ZOU Xiao-bo*, LI Zhi-huang, SHI Ji-yong
DOI: 10.3964/j.issn.1000-0593(2020)11-3549-07
Tofu was a traditional food in China in two thousand years. However, it is still mainly produced by individual workshop, and the security and uniformity of quality is difficult to guarantee. Water and protein content are important factors which affecting the quality of tofu. The traditional detection method for water and protein is complicated, time consuming and laborious. The detection results are often later than the production process which unable to guide tofu production in time. Therefore, it is necessary to develop a new method for quantitatively describing homogeneity of water and protein distribution in Tofu. It is also the a scientific basis for accurately regulating the production process of tofu. In this study, hyperspectral imaging technique combined with chemometrics method were used to detect the changes of water and protein content and distribution under four different conditions: soybean milk, hot soybean milk, gel and tofu. The hyperspectral image of 120 samples in each state was collected in the wavelength range of 432 to 963 nm. Use ENVI software to select the region of interest and calculate the average spectral data of the sample. The original spectrum was pre-processed by convolution smoothing (Savitzky-Golay, SG) as well as multiplicative scatter correction (MSC) to eliminate the influence of spectral noise. A partial least squares regression (PLSR) and principal component regression (PCR) quantitative model were established for the pre-processed spectral data. The prediction results of water and protein by using PCR model are lower than the PLSR model, therefore, the PLSR model is selected as the optimal model. The characteristic wavelengths of soybean milk,hot soybean milk,gel and tofu samples were selected by continuous projection algorithm (SPA), 13, 90, 8 and 9 characteristic wavelengths to establish the PLSR model based on the characteristic wavelengths. The results show that the SPA+PLSR model based on the characteristic wavelengths is better than the PLSR model under the full-band model. The prediction model Rp for for water is 0.84~0.96, and the prediction model Rp for protein is 0.92~0.97. Based on the SPA+PLSR model with better prediction effect, the water and protein contents of different states pixel in the image of soybean milk, hot soybean milk, gel and tofu, were calculated and the water and protein distributions in the sample were visualized with different colors. The feasibility of hyperspectral technology for detecting water and protein contents in tofu was verified, which could be used to solve the defects of traditional detection methods, as well as provided a theoretical basis for the industrialization and intelligence of tofu production.
2020 Vol. 40 (11): 3549-3555 [Abstract] ( 177 ) RICH HTML PDF (4221 KB)  ( 56 )
3556 Ripeness Assessment of Tomato Fruit by Optical Absorption and Scattering Coefficient Spectra
HUANG Yu-ping1, WANG De-zhen1, ZHOU Hai-yan1, YANG Yu-tu1, CHEN Kun-jie2*
DOI: 10.3964/j.issn.1000-0593(2020)11-3556-06
Maturity is one of the most important parameters in determining the picking time and assessing the postharvest quality. As the maturity of tomato fruit advanced, the chlorophyll content decreases, while anthocyanin starts to increase, resulting in color changes for tomato fruit, which suggests color characteristics is closely related to the maturity for tomatoes. The total 600 tomatoes at six maturity stages were used for the test, absorption and reduced scattering coefficients for tomato fruit were extracted by spatially resolved spectroscopy, partial least squares models discriminant analysis (PLSDA) models were built for evaluating tomato maturity. Spatially resolved (SR) spectra for each tomato sample were acquired using a novel spatially resolved spectroscopic system over the spectral region of 550~1 650 nm. Since the 30 fibers in SR probe were arranged in symmetry, each pair of symmetric spectra were averaged, which resulted in 15 relative reflectance spectra covering the light source-detector distances of 1.5~36 mm. Due to strong water absorption beyond 1 300 nm, only 550~1 300 nm was selected for extracting the absorption and reduced scattering coefficients of tomato fruit. Besides,nine SR spectra over the spatial distances from 1.5 to 12.5 mm were actually used to analyze the absorption and reduced scattering properties of tomato fruit in this study, because the signal beyond 12.5 mm was too weak to be useful. And then the values for the absorption and reduced scattering coefficient were obtained by the diffusion approximation equation coupled with a nonlinear inverse algorithm. Chlorophylls content decreases at 675 nm along with the increases of anthocyanin at 560 nm as tomato turns from green to red. The values of the reduced scattering coefficient decreased steadily with the increasing wavelength for all tested tomato samples over the spectral region of 550~1 300 nm. The classification results were compared using μa and μs. Besides, tomato maturity stages were evaluated based on surface color and internal color. The results showed the combinations of μa and μs could further improve classification results compared with single μa and μs spectra, especially μa×μs (multiplication of the two parameters wavelength by wavelength),which presented recognition rate of 78.5% and 85.5% for internal color and surface color, respectively. Better classification results were obtained for three ripeness stages using μa and μs and their combinations, and the recognition rates were similar, around 94% for internal and surface color. The research demonstrated the optical absorption and scattering spectra could classify tomato ripeness stages effectively. The research provided a new means for nondestructive detection in agricultural products.
2020 Vol. 40 (11): 3556-3561 [Abstract] ( 240 ) RICH HTML PDF (2432 KB)  ( 61 )
3562 Study on Cefradine Granules Component Analysis and Calibration Transfer Method Based on Near-Infrared Spectroscopy
ZHOU Zi-kun1, 2, LI Chen-xi2 *, WANG Zhe1, 2, LIU Rong1, 2, CHEN Wen-liang1, 2, XU Ke-xin1, 2
DOI: 10.3964/j.issn.1000-0593(2020)11-3562-05
Near-infrared spectroscopy (NIRS) technology has distinct advantages in component detection for its characteristics of high-speed and low-cost, which is essential for the supervision of drug quality and safety. Studying the method of drug component detection based on NIRS technology is significant for improving the level of drug quality supervision. In fact, owing to differences in performance parameters of different spectroscopic instruments, spectra measured are discrepancy, which brings hardship to the realization for quantitative correction models sharing. Therefore, in order to improve analysis efficiency, the calibration transfer method is discussed. In this paper, the establishment of cephalosporins component correction model and calibration transfer method are studied, and a transformation set selection method based on Markov chain (MC) is proposed. Fifty-six samples of cefradine granules in different batches were used. Spectral data were measured by two Fourier spectrometers. For three components of the sample: cefradine, Cefalexin and water, partial least squares (PLS) method was used to establish a quantitative correction model. MC algorithm is used to construct the probability matrix and select the conversion set, which improves the efficiency of model transformation and the prediction accuracy of spectral data. The experimental results show that the quantitative calibration model transfer between different spectroscopic instruments can be realized by using a small number of sample sets. After the model transfer, the relative error of the quantitative calibration model for the three principal components prediction decreases from 9.67%, 52.14%, 19.25% to 4.37%, 31.12%, 11.67%, respectively. The spectral differences between master and slave instruments can be corrected effectively, and the transfer and sharing of measurement spectra and quantitative analysis models of different instruments can be realized. The modeling analysis and model transfer methods studied in this paper also provide technical support for drug composition and quality detection.
2020 Vol. 40 (11): 3562-3566 [Abstract] ( 172 ) RICH HTML PDF (1620 KB)  ( 50 )
3567 Research on the Visualization Differentiation of Atractylodes Lancea Granule Manufactures Based on Hyperspectral Imaging Technology Combined With the Selection of Characteristic Wavelengths
HUANG Ye1, LIU Li2, LIANG Jing2, YANG Hong-xia3, LI Xiao-li4, XU Ning2*
DOI: 10.3964/j.issn.1000-0593(2020)11-3567-06
In order to provide theoretical guidance for the visualization differentiation of Atractylodes Lancea granules based on hyperspectral imaging, competitive adaptive reweighted sampling (CARS) and correlation analysis (CA) was used to select two characteristic wavelengths. A new method for traceability of Atractylodes Lancea granules using near-infrared hyperspectral imaging technology was proposed. Hyperspectral image of 150 Atractylodes Lancea granules from three manufacturers in the range of 874~1 734 nm, extracting the spectral reflectance value of the region of interest (ROI) as the input variables for the identification model, and using the proximity algorithm (k-nearest neighbor, KNN), back-propagation neural networks (BPNN), partial least squares-discrimination analysis (PLS-DA) and least square support vector machine (LS-SVM) to establish discriminant models of four algorithms (classifiers). The discrimination effect of three different manufacturers of Atractylodes Lancea granules was discriminated by the evaluation criteria of the model effect (predictive set overall discriminant rate and kappa coefficient). Except for the KNN model, the discriminant rate of the prediction set was 100%, and the kappa coefficient was 1. In order to speed up the operation, this study selected the characteristic wavelengths by CARS, random frog (RF), successive projections algorithm (SPA) and sequential forward selection (SFS) algorithm, and used CARS, RF, SFS, and SPA combined with the CA algorithm to achieve four sets of optimal wavelengths. Four (975, 1 220, 1 419, 1 476 nm), two (1 005, 1 442 nm), four (924, 1 005, 1 419, 1 584 nm) and three (948, 1 146, 1 412 nm) optimal wavelengths were obtained respectively, and KNN, BPNN, PLS-DA, and LS-SVM discriminant models were established. Therefore, in the case of screening three optimal algorithms, the best modeling effect that can be obtained with fewer feature wavelengths was: the overall discriminant rate of the prediction set in the CARS-CA-LS-SVM model was 100%, the kappa coefficient was 1. Finally, the spectral data of each pixel of the wavelength variables selected by CARS-CA were input into the LS-SVM model, and the discrimination results were visually displayed in different colors. This study provides a method for the rapid and lossless traceability of Atractylodes Lancea granules product, and provides technical support for the rapid supervision of related organizations in the future.
2020 Vol. 40 (11): 3567-3572 [Abstract] ( 161 ) RICH HTML PDF (3383 KB)  ( 57 )
3573 Study on Establishment of Near-Infrared Quantitative Model for Salvianolic Acid B in Naoxintong Capsule Based on the System Modeling Idea
GAO Rui-lin1, YANG Peng-shuo1, XU Gang2, WU Xiao-wen1, YANG Chang1, SHI Xin-yuan1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3573-06
NIR quantitative modeling mainly involves four process parameters: the selection of sample set, spectra pre-processing, latent variables and variable selection methods. And in the traditional method, the optimization of the PLS modeling parameters was step by step according to the model evaluation indexes and the inter-influence among the parameters was rarely considered in the model development. This is risky because the modeling path is not necessarily the best approach to step by step optimization. The system modeling method is global trajectory parameter optimization idea based on the correlation between the parameters, which is a systematic approach to improve the efficiency and accuracy in the development of a quantitative model. The purpose of this study is based on the system modeling idea to develop a NIR quantitative model for the analysis of salvianolic acid B in Naoxintong capsule. The content of salvianolic acid B in 56 samples of Salvia miltiorrhiza was determined by high-performance liquid chromatography (HPLC), and the near-infrared spectra were also collected. D-optimization design method was used to optimize the modeling parameters including the sample set partition, spectral pre-processing, latent variable factor number and variable selection. The global optimal parameter trajectory was applied in the preparation of the quantitative analysis model. The results showed that the best quantitative model was developed by the spectral data pretreatment of 2D+SNV (2nd Derivative + Standard Normal Variate), choosing the latent variable factor number of 7 and spectral region of 4 000~10 000 cm-1 in combination with the 56 samples were randomly divided into a calibration set and a validation set according to the proportion of 3∶1 by a K-S algorithm. Its standard deviation of calibration (RMSEC) and prediction (RMSEP) were both 0.001 8, which demonstrated the high analytical accuracy and robust fitting. The calibration coefficient of determination (R2cal) and the prediction coefficient of determination (R2pre) were 0.994 0 and 0.995 2, respectively. The ratio of the standard error of prediction to the standard deviation (RPD) was 9.19, further confirming that the model can be used for high-quality quantitative analysis. Based on the system modeling idea, the D-optimal design approach was adopted to implement the global trajectory parameter optimization in the process of establishing the quantitative model in this paper. Furthermore, a quantitative model for salvianolic acid B was developed with robust predictability and high accuracy. The model provided an efficient and rapid method to quantify salvianolic acid B of Naoxintong capsule, which was of great significance for the quality control of intermediates and products of Naoxintong capsule.
2020 Vol. 40 (11): 3573-3578 [Abstract] ( 158 ) RICH HTML PDF (1605 KB)  ( 43 )
3579 Changes of Tumor Cell Components Induced by Pain-Related Neuropeptides SP Investigated by Synchrotron Radiation Infrared Microscopic Imaging Technology
YANG Chao1, ZHU Zhen2, LI Jing4, SUN Yun-heng5, OUYANG Xue-yan1, WANG Jia-wei2, HUANG Qian1, DING Gang3, WANG Yao-sheng1*, JIANG Feng1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3579-06
Pain is one of the most common symptoms in cancer patients, but for a long time, the control of pain symptoms in clinical cancer treatment still cannot get enough attention. The mechanism of pain promoting tumor has not been fully understood. Substance P (SP), as a neuropeptide mediating pain, is highly expressed in serum of patients with cancer pain. In this study, the SP stimulated tumor cells were collected and analyzed by synchrotron radiation microscopic infrared spectroscopy imaging, in order to reveal the possible mechanism of pain promoting tumor. Results show that in the breast cancer cell lines MDA-MB-231, MCF-7, and lung cancer cell lines A549, SPCA, the absorption peak of amide I near 1 655 cm-1 which reflect the secondary structure of the protein, showed blue shift. Suggesting that SP stimulate tumor cells may cause tumor cell protein secondary structure change. In MDA-MB-231 and A549, the absorption peaks of amide I and amide II which located in 1 500~1 600 and 1 600~1 700 cm-1 also declined significantly, show that in the two cell lines, the protein expression of tumor cells is significantly lower. In A549 cell line, the symmetric stretch vibration peaks of phosphodiester group in 1 070~1 090 and 1 230~1 250 cm-1 show blue shift, indicating that SP stimulated A549 cell lines also affected the nucleic acid structure of this cell line, suggesting that SP may cause the damage of tumor suppressor genes and the activation of oncogenes. Synchrotron radiation micro-infrared imaging analysis revealed that persistent pain symptoms affect the biological activity of tumor cells through the release of neurotransmitters, possibly by changing the structure of proteins and nucleic acids in tumor cells. The results of spectroscopy showed that the presence of pain and other adverse symptoms and the release of pain-related substances may affect the protein structure and expression in tumor cells and the change of nucleic acid in tumor cells, which might have adverse effects on the treatment of tumors. In clinical tumor treatment, attention should be paid not only to killing tumor cells but also to symptomatic control of symptoms.
2020 Vol. 40 (11): 3579-3584 [Abstract] ( 198 ) RICH HTML PDF (1422 KB)  ( 72 )
3585 Chemical Construction Changes of Compression Wood Main Components in Longitudinal Tension by the FTIR Analysis
WANG Dong1, 2, LIN Lan-ying2*, FU Feng1, HU La3
DOI: 10.3964/j.issn.1000-0593(2020)11-3585-05
The adaptive growth of compression wood (CW) leads to the changes of chemical properties of coniferous wood, which the change of microfibril angle (MFA) affects the wood mechanical properties and macromolecular deformation. In this paper, the Fourier transform infrared spectroscopy (FTIR) was explored together with mechanical loading as a means of studying the molecular responses to the loading of Masson pine CW and normal wood (NW). It is of great significance to study the molecular biological mechanism of the mechanical properties changes of the CW. The results indicated that the MFA, tensile strength along grain and modulus of elasticity of the CW were 35.17°±2.30°, (45.37±3.41) and (18.10±0.76) MPa, respectively, and were 15.15°±1.61°, (109.75±11.87) and (70.95±6.60) MPa of the NW. What is more, the strain at the break-point of the CW was three times than that of the NW. The FTIR results indicated that the wavenumber shifts of the FTIR bands at 1 161 and 3 348 cm-1 showed an approximately linear relationship with strain. The C—O—C of cellulose at 1 161 cm-1 band shifted to lower wavenumber with tensile strain increase, and shift rate was 2.15 and 1.52 cm-1·dε-1 for the CW and NW, respectively. Furthermore, the O(3)H…O(5) of cellulose intramolecular 3 348 cm-1 bands shifted to higher wavenumber, and shift rate was 4.62 and 2.76 cm-1·dε-1 of the CW and NW, respectively. The shift rates of 1 161 and 3 348 cm-1 bands of NW were more than that of CW. However, the characteristic peaks of lignin and hemicellulose were shown not to be affected. The above results indicate that the cellulose mainly provides the strength of the wood and the matrix of hemicellulose and lignin is benefited to load transform between cellulose microfibrils. Compared with the NW, the larger orientation of microfiber of the CW leads to smaller tension deformation along the direction of cellulose molecular chain, but the larger of shear deformation between microfibrils and matrix. This also leads to a large yield deformation in the tensile process of the CW, and the strain of the failure point is greater than the NW.
2020 Vol. 40 (11): 3585-3589 [Abstract] ( 182 ) RICH HTML PDF (2909 KB)  ( 47 )
3590 Determination of Trace Urea by Resonance Rayleigh Scattering-Energy Transfer Spectroscopy Coupled With Polystyrene Nanoprobe and Dimethylglyoxime Reaction
YAO Dong-mei1, 2, LU Shan-shan1, WEN Gui-qing1, LIANG Ai-hui1, JIANG Zhi-liang1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3590-04
Urea is the final product of amino acid metabolism and is widely used in agriculture as a nitrogen fertilizer. However, when the concentration of urea accumulates to a certain value in the human body, it will cause certain damage to the organs of the human body. Therefore, it is of great significance to establish a simple and sensitive method for urea detection. Resonance Rayleigh Scattering (RRS) is a molecular spectroscopy technique with simple operation, good sensitivity and low energy consumption. It has been widely used in the fields of chemistry and life sciences. At present, the application of the resonance Rayleigh scattering technique to the quantitative analysis of urea has also been reported, but there are still problems such as complicated operation and low sensitivity. In this paper, a simple, rapid and sensitive resonant Rayleigh scattering-energy transfer (RRS-ET) method is developed for the detection of trace urea (UR) in human urine. In the presence of HCl and the stabilizer thiosemicarbazone (TSC), dimethylglyoxime (DMG) can react with UR to form a stable red diazine derivative of 4,5-dimethyl-2-imidazolidone (DIK). The RRS-ET phenomenon occurs between DIK as an energy acceptor and an energy donor polystyrene nanoprobe (PS), which causes the RRS signal of the system to change. Within a certain range, as the UR concentration increases, the RRS intensity at 500 nm decreases linearly. In order to achieve the best detection results, the factors affecting the system signal are optimized. The results show that when the concentration of HCl solution is 0.75 mol·L-1, the concentration of TSC solution is 0.22 mmol·L-1, the concentration of DMG solution is 19.35 mmol·L-1, the concentration of PS is 17.5 μg·mL-1, the temperature of the water bath is 80 ℃, and the bath time is 20 min, the system obtains the best detection effect. Under the optimal conditions, the resonance Rayleigh scattering signal reduction value of the polystyrene nanoparticle system is linear with the UR concentration in the range of 2.0~3 200 ng·mL-1, and the detection limit is 2.0 ng·mL-1. At the same time, the effect of coexisting substances on the determination of 2 000 ng·mL-1 UR is investigated. The results show that 100 μg·mL-1 of Na+, Zn2+, 20 μg·mL-1 of Mn2+, Cr3+, 10 μg·mL-1 of SO2-4, NO-3, Co2+, Fe3+, 2 μg·mL-1 Cr6+ and Ca2+ did not interfere with UR determination. The results show that the method has good selectivity. Finally, the RRS-ET method is applied to the determination of UR in the urine. The recovery of the spiked samples is 94.19%~96.94%, and the relative standard deviation (RSD) is 4.20%~6.35%. The test results are satisfactory. Based on this, a new method of resonance Rayleigh scattering-energy transfer analysis of urea is established with simple operation and high sensitivity.
2020 Vol. 40 (11): 3590-3593 [Abstract] ( 157 ) RICH HTML PDF (1698 KB)  ( 35 )
3594 Effect of Substituent Structure of Benzothiazole Probe on Recognition to Metal Ion
JIA Hui-jie, ZHU Ning, GAO Yuan-yuan, WANG Ya-qi, SUO Quan-ling*
DOI: 10.3964/j.issn.1000-0593(2020)11-3594-05
For the characteristics of fast detection and good selectivity about fluorescence probe for recognition to metal ions, the synthesis of probes 6-(3,5-dimethyl phenoxy)-5-amine-2-phenylbenzothiazole (L4) and 6-(3,5-dimethyl phenoxy)-5-benzamide-2-benzothiazole (L5) was designed. The molecule structures of L4 and L5 were confirmed by spectroscopic characterization and single crystal diffraction analysis. The effects of probes L4 and L5 on recognizing to trivalent metal ions Al3+, Cr3+, Fe3+and divalent metal ion Cu2+ in the solution were investigated in detail by UV-Vis and fluorescence. The results showed when the molecule of probe L5 was formed by the benzoyl recognizing group bonding with the amine group of probe L4, the fluorescence of probe L4 was quenched, and the turn-on fluorescent probe L4 and the turn-off fluorescent probe L5 were simultaneously obtained. The UV-Vis results show that probe L4 could selectively identify to Al3+, Fe3+, Cu2+ in the organic solution and highly selectively identify to Cu2+ in the aqueous acetonitrile solution. A test paper of probe L4 could effectively identify to Cu2+ in pure water by the naked eye detection under UV irradiation. Probe L5 could selectively identify to Al3+ and Fe3+ in the organic solution. The fluorescence results show the fluorescence of probe L4 was quenched while probe L4 with Fe3+, Al3+, Cu2+ were coexisted in the organic solution, respectively. Probe L4 could highly selectively recognize to Cu2+ in the aqueous acetonitrile solution. The fluorescence intensity of probe L5 was successively increased while probe L5 with Cr3+, Fe3+, Al3+ and Cu2+ were coexisted in the organic solution, respectively. According to the L4 solution concentration to the absorption intensity was plotted, and the detection limit of probe L4 to Cu2+ is 4.51×10-6 and the complex constant is 1.12×103 M-1. The detection limits of probe L5 to Al3+, Cr3+, Fe3+, Cu2+ are 2.85×10-6, 4.79×10-6, 5.95×10-6 and 3.23×10-6 mol·L-1, respectively, and the complex constants of probe L5 to Al3+, Cr3+, Fe3+, Cu2+ are 2.17×103, 2.06×103, 3.92×103, 4.43×103 M-1, respectively. It was inferred that 1∶1 complex was formed by the linkage of probes with metal ions on the basis of the results of fluorescence titrations. The results of anti-interference to other metal ions display the identification to specific metal ions by probes is not affected by other interference metal ions. 1H NMR results show the amine group and dimethyl phenoxy group of probe L4 and the benzamide group and dimethyl phenoxy group of probe L5 play an important role in the identification of metal ions. Probe L4 has a positive application prospect on identifying to copper ions.
2020 Vol. 40 (11): 3594-3598 [Abstract] ( 152 ) RICH HTML PDF (2359 KB)  ( 45 )
3599 Quantitative Analysis Method for Mixture With Known Components Based on Raman Spectroscopy
YAN Fan1, ZHU Qi-bing1*, HUANG Min1, LIU Cai-zheng1, LEI Ze-min2, ZHANG Heng2, ZHANG Li-wen2,LI Min2
DOI: 10.3964/j.issn.1000-0593(2020)11-3599-07
Quantitative analysis of mixture components by Raman spectroscopy is a difficult problem in analytical chemistry.The existing quantitative analysis methods of the mixture based on machine learning (such as support vector regression, partial least squares) have the problems of difficult to obtain training samples and poor generalization performance of models. A direct quantitative analysis method for mixture with known components based on Raman peak intensity and the least square fitting algorithm was proposed in this study. Firstly, the Raman spectra of the mixture and its components were collected respectively, and the noise reduction and baseline correctionforthe Raman spectra were conducted by using the combination of continuous wavelet transform and penalized least square method. Secondly, the preprocessed spectra were divided into several spectral subintervals by slope comparison method, each subinterval was regarded as the linear superposition of several Voigt functions, and the positions, intensities and half-widths of the peaks were obtained by Levenberg-Marquardt-Fletcher (LMF) algorithm. Thirdly, the contribution value of each component to the spectral peak of the mixture was determined based on the peak position. Finally, the over determined equation was established based on lambert-beer law thatthe peak intensity of mixture is proportional to its concentration of components, the coefficients corresponding to each component were obtained by fitting the equation with the least square method, so that the volume concentration of each component was obtained. In this study, ten kinds of ternary mixtures (9 volume concentration ratios of each ternary mixture) were prepared with 6 components, including ethanol, acetonitrile, acetone, cyclohexane, diacetone alcohol and diethyl malonate, and Raman spectral data of 90 mixtures and 6 components were collected. If the spectra of mixtures and their components were acquired at the same measurement conditions (power and integral time), the obtained correlation coefficient (r) foreach componentwas above 0.96, the root means square error (RMSE) was less than 6%, and the residual prediction deviation (RPD) was greater than 2.5. If the spectra of mixtures and their components were acquired at the different measurement conditions, the correlation coefficient (r) was above 0.93, the RMSE was less than 7.94%, and the RPD was greater than 2.0, this proved that the algorithm has good accuracy and robustness for quantitative analysis of mixture based on Raman spectroscopy. The proposed method can achieve a arapid and accurate direct quantitative analysis of ternary mixtures, which provides an effective way for the quantitative analysis of mixtures.
2020 Vol. 40 (11): 3599-3605 [Abstract] ( 248 ) RICH HTML PDF (3273 KB)  ( 154 )
3606 Two-Dimensional Perturbation Correlation Infrared Spectroscopy Analysis of Animal Manure Biochar
GUI Xiang-yang1,2, LIU Chen3, XU Ji-hong1, DUAN Fang-lei1, FANG Shu-wei1, LI Fei-yue1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3606-07
More attention has been paid to biochar which has been hot research area as a novel environmental functional material due to its special structure and physicochemical properties, it has multiple environmental benefits such as pollution remediation, soil improvement, carbon sequestration and emission reduction. The physicochemical properties of biochar were determined by the types and distribution of surface functional groups. Pyrolysis temperature and material type are two important factors affecting functional groups of biochar. In this article, animal manure biochars were prepared under different temperature from 200 ℃ to 700 ℃ with the materials of chicken manure, dairy manure and pig manure. On the basis of traditional one-dimensional infrared spectrum analysis, the change tendency of functional groups of animal manure biochars with the increase of pyrolysis temperature was revealed using the method of Fourier transform infrared spectroscopy (FTIR) combined with two-dimensional correlation analysis, providing a theoretical basis for better research on structure-activity relationship of biochar. The results showed that with the increase of pyrolysis temperature, Which variations mainly existed in the unceasing weakening of alcohols and phenols —OH peak and aliphatic —CH2 peak of manure biochar, among which the changes of chicken manure were the most obvious. Furthermore, the changing intensity of —OH was higher than —CH2 and was removed before —CH2 in the range of 3 600~2 800 cm-1. The number of auto-peaks was 6, 5, 6 respectively in the two-dimensional perturbation correlation infrared spectroscopy of chicken, dairy and pig manure biochar. The changing intensity of each auto-peak was (chicken manure biochar) aromatic C═C>C═O>Si—O/C—O>P—O/C—H; (dairy manure biochar) C═O>C═C and P—O/C—H>C—OH, C—O/Si—O; (pig manure biochar) C═O>C═C>COO->Carboxylic C—OH>P—O/C—H═C—O/Si—O. The groups of C═O and C═C broke and reconstituted, and C═O broke ahead of C═C. However, there were differences in the functional groups of different animal manure biochars, mainly the change of C—O/Si—O was prior to P—O/C—H in chicken manure biochar, while P—O/C—H in dairy manure biochar changed earlier than C—O/Si—O, and C—O/Si—O and P—O/C—H in pig manure biochar occurred simultaneously in the range of 1 800~800 cm-1.
2020 Vol. 40 (11): 3606-3612 [Abstract] ( 222 ) RICH HTML PDF (6190 KB)  ( 97 )
3613 Plasma Emission Spectroscopy Analysis of Two-Way Microwave Coupled Reaction Cavity
LI Fang-hui, HE Zhong-wen, CAO Wei, ZHAO Hong-yang, FU Qiu-ming, XU Chuan-bo, MA Zhi-bin*
DOI: 10.3964/j.issn.1000-0593(2020)11-3613-04
The reaction chamber is used as the core of the optical fiber preform by microwave plasma chemical vapor deposition. The structure directly affects the electromagnetic field distribution in the reaction chamber, which affects the plasma state. Therefore, it is necessary to study the structure of the reaction chamber. In order to obtain plasma with higher density and better uniformity in the reaction chamber, a two-way microwave coupled reaction chamber structure was proposed. Firstly, the electric field distribution in the reaction chamber under different reaction chamber structural parameters was simulated and calculated. The effect of the reaction chamber structure and working pressure on the plasma distribution in the quartz tube was investigated by plasma emission spectroscopy using oxygen as the working gas. The results showed that the two-way microwave input method produces a strong electric field coupling enhancement effect in the central region of the quartz tube. The inner diameter of the reaction chamber had a great influence on the electric field distribution state. When the inner diameter of the reaction chamber was 86 mm, the electric field distribution in the quartz tube exhibits axis symmetry, and the plasma density in the axial center region was the largest. When the distance between the two rectangular waveguides was 61.2 mm, and uhe length of the reaction chamber was 202 mm, the intensity and uniformity of the plasma in the reaction chamber were optimally distributed. It was also found that when the pressure rises from 1.8 to 2.8 kPa, the spectral intensity of the plasma in the reaction chamber decreased, but the change near the inner wall of the quartz tube was not obvious, which was caused by the energy loss caused by the increase of particle collision probability in the plasma and the high temperature of the tube wall.
2020 Vol. 40 (11): 3613-3616 [Abstract] ( 140 ) RICH HTML PDF (2527 KB)  ( 54 )
3617 Laser-Induced Breakdown Spectroscopy for Heavy Metal Analysis of Zn of Ocean Sediments
ZHANG Chao, ZHU Lin, GUO Jin-jia*, LI Nan, TIAN Ye, ZHENG Rong-er
DOI: 10.3964/j.issn.1000-0593(2020)11-3617-06
With the rapid development of economy, the intensely deepening pollutions in the ocean and rivers have become a major issue. As a key indicator of environmental assessment, the sediments can offer important information on heavy metal pollution. Infield investigation, rapid and real-time detection method for sediments is lacking for the time being. With the advantages of fast and real-time analysis, simple sample pretreatment, multiple element detection, Laser-induced Breakdown Spectroscopy (LIBS) can meet the requirements of field sediment probe. In this paper, a portable LIBS system was developed and used for the element of Zn detection from sediment samples.The system was equipped with a Nd:YAG pulses laser as the source and a miniature optical fiber spectrometer. With a size of 371 mm×192 mm×294 mm, the system was convenient for field measurement. To quantify the Zn in sediment samples, the LIBS spectra of sediments obtained after the samples pretreatment shouldbe standardized in the first step. The best method was standardized with characteristic plasma parameters through a comparison with some typical methods to reduce the relative standard deviation (RSD) to its fifth of original data. A backpropagation artificial neural network (BPNN) with the driving factorwas adopted as the calibration model for quantitation. An R2 value over 0.99 and a twice better predictive result were achieved with the single variable analysis. Also, we found that the spectral intensity of sediments was not significantly affected by drying longer than 12 minutes. Therefore, LIBS detection can be carried out after a 12-minute drying to the samples in the field investigation. The field experiment was made at 6 different sampling sites in Jiaozhou Bay using the portable LIBS system. A LIBS detection can be carried out after a 12-minute drying to the samples in the field investigation. The concentration prediction of Zn was got by using of the above methods. The results showed their coincidencein comparison with the results using Atomic Absorption Spectroscopy (AAS) method with the average relative deviation of 8.32%. The obtained results proved the performance of the portable LIBS system in field sediment sample analysis and showed the applicability for predicting Zn concentration using the standardization with characteristic plasma parameters and BPNN combined approach.
2020 Vol. 40 (11): 3617-3622 [Abstract] ( 178 ) RICH HTML PDF (5140 KB)  ( 110 )
3623 FTIR Spectral and Microscope Analysis of Textile Residues on the Surface of the Bag for Storing Bows Excavated From Qin Shihuang’s Terra-Cotta Warriors Museum
YANG Lu1, 3, 4, HUANG Jian-hua2, 5, SHEN Mao-sheng2, YU Meng-nan1, 2, WANG Li-qin1, 4, WEI Yin-mao3
DOI: 10.3964/j.issn.1000-0593(2020)11-3623-05
For the investigation of the textile residues on the surface of the bag for storing bows in Qin dynasty, which was discovered in the third archaeological excavation of Qin Shihuang’s Terra-Cotta Warriors, the Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and Three-dimensional Video Microscope were used in the analysis. From the residues’ Fourier transform infrared spectra, it can be seen the features of plant fiber, the vibration bands of the beta-D-glucoside bond in cellulose at 876 cm-1 wave number, and the stretching vibration peaks of the C—O ether bond in the glucose ring of cellulose at 1 080 cm-1 wave number and 1 033 cm-1 wave number. There are some other characteristic peaks in the spectra, for example, the peak of conjugated carbonyl and C═C stretching vibration in lignin in 1 637 cm-1, bending vibration peaks of CH2 in cellulose and lignin in 1 434 cm-1. According to the infrared spectrum characteristics of several common plant fibers in ancient, it was found that the textile trace on the surface of the bag for storing bows was closer to ramie. The microstructure of the textile residues cannot be seen under the SEM. The surface morphology of the samples was uniform, showing a fine sheet-like barrier junction, and no parallel arrangement of fibers and surface joint information was found. The disappearance of the physical structure of fibers was due to the long burial and degradation of textiles. The density of longitude and weft is 9×9 cm2. Compared with the textile traces unearthed from other sites, the textile density of the sample does not meet the requirements of making clothing for sparse in longitude and latitude. The diameter of the textile longitude and weft is (0.965±0.029) and (0.982±0.019) mm respectively, 95% confidence level. The difference between longitude and weft diameters is not significant by independent sample t-test. Based on the above results, it is concluded that ramie textiles were wrapped on the surface of the bag for storing bows in the Qin dynasty. It is reasonable to infer that the usage of ramie is easy for handling or reinforcing the bag.
2020 Vol. 40 (11): 3623-3627 [Abstract] ( 163 ) RICH HTML PDF (3265 KB)  ( 51 )
3628 Investigating and Studying of the Sooty Murals at Mutisi Grottoes With the Infrared Photography
ZHANG Yao1, LI Bo2, ZHENG Yu2, MA Xian-jun3, GUO Hong1*
DOI: 10.3964/j.issn.1000-0593(2020)11-3628-05
As one of the oldest painting art forms, the mural is an extremely important cultural relic. This kind of painting, which expresses the author’s ideas, decorate buildings, propagates ideas and expresses religious worship through images and colors, exists in every aspect and corner of historical life. Because of the religious activities, production and other human factors intervention in history, there are a large number of sooty murals in grottoes and temples. The contents and styles of murals cannot be identified by conventional methods. We still cannot completely remove the sooty layer on the murals with the effective technical means without any damage, so the study and appreciation of murals are seriously affected. Because of the different absorptivity of all kinds of pigments used in the murals under the infrared light, we can achieve the distinction. Using the property of infrared spectrum which can penetrate the surface of the material, the investigation and study of the sooty murals can be identified clearly. Infrared photography has been used in the study of the murals in large buddhist grottoes for a long time, but it has not been widely used in the study of ancient murals, especially in small-scale and medium-scale grottoes. In this paper, the sooty murals of the MutisiGrottoes which are the representation of small-scale grottoes in the Southeast of Gansu were studied by using infrared photography. It provides important information about the contents of the images, the ink lines of the manuscripts and even the modification marks which cannot be observed in visible light. It is also helpful to infer the date of the painting. The local details can be further obtained by adjusting the tolerance and color levels of the infrared images. This paper makes up for the lack of infrared photography in the study of small-scale and medium-scale grottoes. At the same time, it can also be used as detailed information on the present preservation status of murals, which is helpful for the protection and restoration of murals. Infrared photography has a great significance for the study of ancient sooty murals with non-contact, lossless, fast and intuitive properties. This method can be popularized in the study of the murals in the grottoes and temples and plays a key role in the study of ancient sooty murals.
2020 Vol. 40 (11): 3628-3632 [Abstract] ( 157 ) RICH HTML PDF (3077 KB)  ( 40 )
3633 Study on Correction Algorithms of Characteristic Peak Drift in X-Ray Spectrum
TANG Lin1,2,3, LIAO Xian-li1*, LIU Xing-yue1, ZHAO Yong-xin1, LI Yue-peng1, YU Song-ke1,3
DOI: 10.3964/j.issn.1000-0593(2020)11-3633-06
In order to solve the problem of abrupt pulse appearing in switch reset preamplifier of high-performance silicon drift detector using digital slow triangulation algorithm and the problem of characteristic peak drift caused by amplitude damage of such pulse after forming, a correction algorithm of characteristic peak drift based on abrupt pulse repair is proposed. The algorithm includes the following processes. Firstly, the weak current signal output by the former circuit is converted into the negative exponential signal by CR differential circuit,and then, the amplitude range of the negative index signal amplified by the three-stage amplifier is 0~2 V, and the amplitude range is kept in the processing range of the back-end analog-to-digital converter. The digital negative index pulse sequence is obtained by the analog-to-digital conversion of the amplified negative index signal. Through the judgment of the sampling points of the above negative index pulse sequence, when the continuous multiple sampling points are zero, the pulse is marked as abrupt pulses. At last, the fast and slow correction algorithms are used to repair the abrupt pulses, and the repaired negative index pulse sequence is processed by digital trapezoid forming, and the forming results are stored in FIFO for multi-channel spectrum generation. In the experiment, self-made iron ore samples were taken as the measurement object, and the uncorrected original spectrum is compared with the spectrum obtained by different correction methods. The results show that the counting rate of the shadow peaks of the corrected Fe and Sr characteristic peaks in the channel address range is significantly lower than that of the uncorrected original spectrum. At the same time, the number of the channel address intervals of the two characteristic peaks of Fe and Sr is significantly higher than that of uncorrected. Because the drift of the counting rate of the characteristic peak is the root cause of the shadow peak, the decreasing value of the counting rate of the same element in the shadow peak area should be consistent with the increasing value of the counting rate in the characteristic peak area. The results show that the difference of counting rate between the fast correction and slow correction of the shadow peak and the characteristic peak of Fe element is basically consistent with this trend, but the difference of counting rate between the fast correction and the fast correction of strontium element shadow peak and the characteristic peak of Sr element is large, which does not conform to the rule that the decrease of the shadow peak count is the increase of the characteristic peak count. The basic reason for this result is that the fast correction is not complete for the repair of abrupt pulse, and the slow correction can better achieve the repair of all sampling points. The final repair efficiency also shows that for the same interval, the slow correction method has higher repair efficiency and better correction effect for the characteristic peak drift. The results show that the correction algorithm can effectively eliminate the shadow peak in front of the characteristic peak and realize the correction of the characteristic peak drift, which is of great significance for obtaining the fine X-ray spectrum.
2020 Vol. 40 (11): 3633-3638 [Abstract] ( 160 ) RICH HTML PDF (2457 KB)  ( 57 )
3639 Spectroscopic Characteristics of Turquoise With Reddish-Brown Stripes From Shiyan, Hubei Province
KU Ya-lun1, YANG Ming-xing1, 2*, LIU Jia1
DOI: 10.3964/j.issn.1000-0593(2020)11-3639-05
Striped turquoise is a kind of popular variety in the turquoise market of Shiyan, Hubei Province. In this paper, a turquoise sample with the light blue-green substrate and reddish brown stripes was studied. Moreover, reddish brown stripes regularly distributed on the light blue-green turquoise substrate. It has been tested by microscopic observation, EDS, micro-laser Raman spectrometer and micro UV-VIS-NIR. The results show that reddish-brown stripes are formed by the regular gathering of nearly round hematite aggregation in turquoise. Hematite particles are fine and disseminated distributed in the form of dots and snowflakes in turquoise. The results of chemical composition test show that the iron content in the strip is higher than that in the substrate, and the FeOT content in the inclusion minerals is about 56.06%~59.13%. Micro UV-VIS-NIR spectra show the chromogenic ions in the inclusion minerals mainly are Fe3+. It can be seen that the weak absorption near 374nm is caused by the d-electron transition of Fe3+ (6A14E(4D)), the double absorption near 429 and 418 nm is caused by the d-electron transition of Fe3+ (6A14E, 4A1(4G)), and the weak absorption near 475 and 544 nm is caused by the electron transition of Fe3+ ([6A1+6A14T1(4G)+4T1(4G)]). The Raman spectrum of inclusion minerals is typical of hematite at 225,296,411,612,659,1 320 cm-1. The spectroscopic characteristics of inclusion minerals in striped turquoise indicate that the inclusion mineral is hematite. Hematite in the turquoise is the associated mineral in turquoise deposit. The existence of hematite in turquoise can provide data support for the origin identification of turquoise and the origin traceability of ancient turquoise. The periodic appearance of hematite, an inclusion mineral in the Striped turquoise, indicates the instability and periodicity of the formation environment of turquoise.
2020 Vol. 40 (11): 3639-3643 [Abstract] ( 231 ) RICH HTML PDF (2902 KB)  ( 78 )
3644 Eco-Friendly Fabrication of Selenium Nanoparticles by Solidstate Thermal Decomposition of SeCl4-L-Glutamine Precursor: Spectroscopic Characterizations
Sattam Al-Otaibi*
DOI: 10.3964/j.issn.1000-0593(2020)11-3644-05
In this article, spherical black spots-like selenium metal nanoparticles were synthesized. Accordingly, this experimental work proposed an innovative facile, green, one-step and solvent-free strategy to a large scale synthesis of Se-NPs via thermal decomposition of green precursor. The Se(Ⅳ) L-glutamine precursor was prepared by solid state grinding using selenium(Ⅳ) tetrachloride, SeCl4, and L-glutamine for 2 hr without using any organic solvent. It was characterized by infrared spectroscopy, and micro analytical. The solid precursor compound was subsequently annealed in the muffle furnace at 300 ℃ for 3 hr in static air. Selenium NPs was resulted and well characterized using X-ray powder diffraction (XRD), FT-IR spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The FTIR and XRD data showed that the Se NPs is pure and has a good crystalline structure because no characteristic peaks of impurity were detected, while the SEM and TEM results showed that the obtained product is tiny, aggregated with spherical-like shape, narrow size distribution with an average size between 5~10 nm. Results show that the solid state thermal decomposition method is simple, eco-friendly, safe and suitable for preparation of SeNPs. This method can also be applied to synthesize nanoparticles pure metal and metal oxides.
2020 Vol. 40 (11): 3644-3648 [Abstract] ( 149 ) RICH HTML PDF (2341 KB)  ( 68 )
3649 Synthesis and Spectroscopic Characterizations of New Mercury(Ⅱ), Cerium(Ⅲ), and Thorium(Ⅳ) Captopril Drug Complexes
Samy M. El-Megharbel1,2*,Moamen S. Refat1,3
DOI: 10.3964/j.issn.1000-0593(2020)11-3649-04
In this article, three types of metal ions with different oxidation state as mercury(Ⅱ), cerium(Ⅲ) thorium(Ⅳ) have been reacted with captopril drug (CAP). The isolated solid complexes were explained using elemental analysis, conductance measurements, infrared and 1H-NMR spectroscopy as well as the thermo gravimetric (TG/DTG) analysis. The micro analytical and spectroscopic results for all CAP complexes were agreement with the speculated structures. The stoichiometry for divalent Hg2+, trivalent Ce3+ and tetravalent Th4+ metal ions with CAP ligand was established with 1∶2 (Mn+:CAP) molar ratio. The qualitative analysis showed that in case of the mercury(Ⅱ) complex, the chloride ions didn’t involved in the complexity, suggesting formula [Hg(CAP)2] in neutral form. However, regarding both Ce(Ⅲ) and Th(Ⅳ) complexes as [Ce(CAP)2(NO3)]·3H2O and [Th(CAP)2(NO3)2(H2O)]·3H2O formulas, the nitrate group is existed inside the coordination sphere. The infrared analysis data proved that CAP drug act as a bidentate ligand with the metal ions of Ce(Ⅲ) and Th(Ⅳ) through oxygen carbonyl group CO and oxygen of the deprotonated carboxylic COOH group, while for the Hg(Ⅱ) complex, the CAP acts as a bidentate ligand through oxygen of CO group and sulfur atom of the deprotonated —SH group. Thorium(Ⅵ) complex has a nine-coordinate geometry, while Hg(Ⅱ) and Ce(Ⅲ) have a four and six-coordination behaviors respectively. The 1H-NMR data of the CAP compound has a singlet sharp signal at 1.90 ppm due to the proton of —SH group, this peak absent in the spectrum of the Hg(Ⅱ) CAP complex upon the deprotonated of thiol group.
2020 Vol. 40 (11): 3649-3652 [Abstract] ( 142 ) RICH HTML PDF (1655 KB)  ( 78 )