Journals >Spectroscopy and Spectral Analysis
Contents
2017
Volume: 37 Issue 12
55 Article(s)
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A Laser Resonance Ionization Spectroscopy Apparatus for Study on Atomic Energy Level
WANG Wen-liang, LI Zhi-ming, SHEN Xiao-pan, XU Jiang, ZHAI Li-hua, DENG Hu, and WEI Guan-yi
Laser resonance ionization spectroscopy (LRIS) is one of the element-selective spectroscopy methods, which aims to study the energy level parameters of the atom by measuring the ion signal. The atom is selectively excited and ionized by one or more lasers in LRIS. A set of totally domestic LRIS apparatus was built, whiLaser resonance ionization spectroscopy (LRIS) is one of the element-selective spectroscopy methods, which aims to study the energy level parameters of the atom by measuring the ion signal. The atom is selectively excited and ionized by one or more lasers in LRIS. A set of totally domestic LRIS apparatus was built, which was used for measuring the parameters of the atomic high lying states. The overall structure, main technique and application of the LRIS apparatus were described in detail. The LRIS system was consisted of high precision tunable dye lasers, high efficiency laser ionization system and high resolution time of flight mass analyzer (ToF-MA). There were three sets of multimode dye laser and one set of single longitudinal mode dye laser, which were pumped by 532 nm Nd∶YAG laser. The repetition frequency of the dye laser was 10 kHz. The laser ionization system contained atomization source, atom and laser interreaction region and ion lens. The atom sprayed from the atomic source was selectively excited and ionized by lasers, and then was reshaped as ion beam with small divergence angle and narrow beam width by ion lens. The reflecting structural design, pulsing vertical repulsion technique and deflecting plate adjusting method were adopted in the ToF-MA. Based on the laser resonance ionization spectroscopy technique, the auto-ionization spectrum of uranium atom was measured with the aid of this apparatus. An efficient three-color-three-photon resonance ionization scheme of uranium atom was obtained. The center wavelengths of the lasers were 591.7, 565.0 and 632.4 nm, respectively. The isotopic shift and the hyperfine structure also can be analyzed by this apparatus. In addition, as result of the mass analyzer employment, the proposed apparatus can be used to analyze the sample component, trace element concentration, and isotopic abundance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3653 (2017)
Full State-Resolved Rotational Distribution of CO2 in Collisions with Highly Vibrationally Excited K2
WANG Shu-ying, DAI Kang, and SHEN Yi-fan
Highly vibrationally excited K2(E=3 500 and 4 000 cm-1) was achieved by stimulated emission pumping. The full state-resolved distribution of scattered CO2(0000) molecules from collisions with excited K2(E) was reported. The donor energy dependence for full J-state distribution of energy upstate in collisions has been iHighly vibrationally excited K2(E=3 500 and 4 000 cm-1) was achieved by stimulated emission pumping. The full state-resolved distribution of scattered CO2(0000) molecules from collisions with excited K2(E) was reported. The donor energy dependence for full J-state distribution of energy upstate in collisions has been investigated. Nascent rotational and translational energy profiles for scattered CO2(0000) molecules with J=2～74 were measured using high resolution transient laser induced fluorescence (LIF). The appearance line widths were obtained by fitting the double Gaussian function to the transient line profile data at t=1 μs. Doppler-broadened line widths and the relative (center of mass frame) translational temperatures for appearance and depletion of scattered CO2 molecules, the lab-frame translational temperatures and average translation energy of appearance section for K2(E)/CO2 collisions were determined. The energy transfer mechanism was similar at both donor energies, which was vibration-rotation/translation relaxation mechanism. But collisonal appearance temperatures were beyond the pool temperature, while collisonal depletion temperatures were slightly lower than the pool temperature, and the magnitude of energy transferred into translational energy increased with donor energy. The donor vibrational energy going into translational energy of the collision products was strongly dependent on the initial energy. The translational energy of the J-specific collision products increased by 40% or more for a 14% increase in donor vibrational energy. The nascent rotational distribution of scattered CO2(0000) molecules was shown for collisions with K2(E=3 500 cm-1). The semilog plot showed evidence of a biexponential distribution. A better description of the nascent rotational distribution came from fitting with the sum of two independent distributions. The fitting yielded a low-energy distribution with Ta=(523±60) K and a high energy distribution with Tb=(1 890±210) K. The proximity of Ta to the initial 553 K distribution showed that nearly elastic collisions populated the low J final states, which belong to single quantum relaxation processes. In contrast, the strong collisions that were responsible for the high energy tail were inelastic and involved large increases in J, which belonged to multi-quantum relaxation processes. The full J-state rotational distribution of CO2 from collisions with K2(E=4 000 cm-1) also showed biexponential behavior. Biexponential fitted results in Ta=(620±65) K and Tb=(2 240±250) K. Each of these values at E=3 500 cm-1 was approximately 19% greater than for corresponding values at E=3 500 cm-1. Thus, the highly energy donor molecules imparted more rotational energy for the full range of bath rotational states. The spread of the rotational distribution was sensitive to K2 difference energy, but the branching ratio for elastic and inelastic collisionswas the same The weak collision pathway accounted for ～82% of collisions with CO2(0000) products, while the strong collision pathway accounted for ～18%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3658 (2017)
Implementation of Overlapping Peak Separation Algorithm for Absorption Spectra by Fractal Dimension Analysis in Time-Frequency Domain
TAO Wei-liang, LIU Yan, WANG Xian-pei, and WU Qiong-shui
Because of the natural broadening, Doppler broadening, and collision broadening of spectral lines, multiple adjacent peaks in the absorption spectrum signal of mixed gas with multiple components are often overlapping, which makes the qualitative or quantitative analysis of hybrid gas composition difficult. Existing metBecause of the natural broadening, Doppler broadening, and collision broadening of spectral lines, multiple adjacent peaks in the absorption spectrum signal of mixed gas with multiple components are often overlapping, which makes the qualitative or quantitative analysis of hybrid gas composition difficult. Existing methods have deficiencies in obtaining a prior knowledge, accuracy, and computational efficiency. An overlapping peak separation algorithm for absorption spectra is proposed in this paper, which can identify, locate, and parse independent peaks overlapped in the spectral signal by combining the multiscale observation of wavelet and the self-similarity measure of fractal. Firstly, spectral signal with overlapping peaks was transformed to the time-frequency domain by wavelet, so we can analyze it in light frequency and scale domain. Secondly, the self-similarity of the multi-scale data of the spectral signal at a specified frequency was measured by fractal analysis, which was performed at every frequency in a frequency range of interest to acquire a fractal dimension curve. The fractal dimension curve reflected the self-similarity of the spectral signal at different scales, and the locations of local extremum of the curve were related to the position of the independent peaks. Finally, according to the fact and the feature parameters of the fractal dimension curve, independent peaks generated from mixed gas composition were separated from the spectral signal by an artificial neural network. The proposed algorithm in the paper carried on the fine analysis on the spectral signal at different scales using the multiresolution characteristic of the wavelet, and improved the analytical ability to parse the independent peaks with a high degree of overlap. The automatic measurement of the entire algorithm was realized using the artificial neural network. The validity of the proposed algorithm was verified by the analysis of experimental results, and the main factors that affected the algorithm were discussed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3664 (2017)
Preparation of Au@TiO2-HMME and Its Photodynamic Efficiency
YAO Cui-ping, WANG Jia-zhuang, WANG Jing, ZHANG Lu-wei, WANG Si-jia, and ZHANG Zhen-xi
Photodynamic therapy (PDT) is a potential treatment method that has proven to be an efficient, safe, and minimally invasive technique. The technique mainly depends on photosensitizes to produce reactive oxygen species underthe irradiation of specific wavelengthlight, therefore causing specific killing to tumor cells anPhotodynamic therapy (PDT) is a potential treatment method that has proven to be an efficient, safe, and minimally invasive technique. The technique mainly depends on photosensitizes to produce reactive oxygen species underthe irradiation of specific wavelengthlight, therefore causing specific killing to tumor cells and tissues. Among them, hematoporphyrinmonomethyl ether (HMME) mediated PDT has been used in clinical treatment of port wine stain (PWS) due to its single component, high yield of singlet oxygen and short light-sensitive period. In order to improve the efficiency of the PDT, we synthesized stable, monodispersecation Au nanospheres with absorption peak of 530 nm based on seed-growth. Poly-(sodium 4-styrenesulfonate) (PSS) was employed to modify Au nanospheres owing to its low toxicity and strong anion electrolytic activation. Then TiOH2+ coming from TiCl3 hydrolysis could be closely attached to negatively charged Au nanospheres through electrostatic attraction and further oxidation to obtain AuNP@TiO2 core-shell nanostructure. The TiO2 shell thickness could be adjusted by changing the NaHCO3 amount, then further mixing AuNP@TiO2 core-shell and HMME to form the conjugate. The obtained samples were characterized by UV-visible absorption spectroscopy, infrared spectroscopy, laser nanoparticle size analyzer and transmission electron microscope (TEM). The results showed that the core-shell nanostructures were stable and well-distributed. Otherwise, the cell killing experiments were performed with KB cells and LED array of 510 nm light source, and CKK-8 was used to evaluate the cell viability. The results showed that the conjugate improved PDT efficiency about 35% higher than that of HMME alone..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3670 (2017)
Terahertz Spectroscopy and Density Functional Theory Investigation of 2-Thiobarbituric Acid Polymorphs
ZHANG Qi, FANG Hong-xia, ZHANG Hui-li, QIN Dan, HONG Zhi, and DU Yong
2-Thiobarbituric acid (TBA) is one of the most polymorphic rich molecular solids currently known. Here, five most common polymorphs of TBA (form Ⅰ, Ⅱ, Ⅲ, Ⅳ and hydrate) were investigated using terahertz time-domain spectroscopy (THz-TDS). All results of the terahertz spectra showed that there were significantly differe2-Thiobarbituric acid (TBA) is one of the most polymorphic rich molecular solids currently known. Here, five most common polymorphs of TBA (form Ⅰ, Ⅱ, Ⅲ, Ⅳ and hydrate) were investigated using terahertz time-domain spectroscopy (THz-TDS). All results of the terahertz spectra showed that there were significantly different absorption features for polymorphs, which indicated that THz-TDS technique could effectively identify different types of TBA polymorphs. Form Ⅳ belongs to the tautomeric polymorph, and the absorption features of form Ⅳ at 0.65(broad band), 1.02 and 1.41 THz are significantly different from physical mixture of form Ⅰ and form Ⅱ. Density functional theory (DFT) calculation was performed to optimize two possible molecular structures and simulate the corresponding vibrational spectra. The theoretical result showed that simulated structure (form a) had absorption peaks at 0.41/0.47, 0.89 and 1.35 THz, which agrees with the THz experimental spectrum. Therefore, it is confirmed that, in the TBA form Ⅳ, the first hydrogen bond is formed between thione S7 of isomer A and amide H23 of isomer B in the structure of form Ⅳ, while the second one is constituted by amide H13 of isomer A and thione S20 of isomer B. The characteristic absorption modes of form Ⅳare also assigned based on the simulation results of DFT calculation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3677 (2017)
Wavelet-Based Image Fusion Method Applied in the Terahertz Nondestructive Evaluation
ZHANG Jin, WANG Jie, SHEN Yan, ZHANG Jin-bo, CUI Hong-liang, and SHI Chang-cheng
Glass fiber-reinforced polymer (GFRP) composites are widely used in aerospace, aviation and other military and civilian fields. However, GFRP composites may have several defects due to the damage caused by various factors during the manufacturing processes and in deployment. Terahertz (THz) time-domain spectroscopy (TDGlass fiber-reinforced polymer (GFRP) composites are widely used in aerospace, aviation and other military and civilian fields. However, GFRP composites may have several defects due to the damage caused by various factors during the manufacturing processes and in deployment. Terahertz (THz) time-domain spectroscopy (TDS) imaging technology has the potential to become a powerful complement of the traditional nondestructive evaluation (NDE) methods for GFRP composites. During the imaging process, different parameters in time domain or frequency domain can be chosen to carry out the imaging. Targeting at different defects, the parameters which can effectively detect the defects are not the same. In this paper, the wavelet-based image fusion method is used to effectively combine multiple THz reflection images based on different parameters, and a new image which contains all the defects can be obtained. As shown in the experiments, due to the application of the wavelet-based image fusion method in the THz NDE, the defect information can be detected completely, which cannot be realized by single parameter imaging. It provides a new technical method for the post processing of the THz images of composite materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3683 (2017)
Application of Terahertz Time-Domain Spectroscopy in Fluid Inclusion Study
WU Zhi-kui, BAO Ri-ma, WANG Fang, MIAO Xin-yang, and FENG Cheng-jing
Fluid inclusion is one of the most important methods to study the evolution of mineral crystals, which can reflect the original information of mineral evolution (temperature, pressure, pH, etc). The external factors, such as temperature and pressure in the process of evolutiondirectly affect the quantity and size of inFluid inclusion is one of the most important methods to study the evolution of mineral crystals, which can reflect the original information of mineral evolution (temperature, pressure, pH, etc). The external factors, such as temperature and pressure in the process of evolutiondirectly affect the quantity and size of inclusions, which are related to the properties of crystals. In this paper, terahertz time-domain spectroscopy was used to detect KCl crystals with different growth temperature, and the curves of time domain, frequency domain and absorption coefficient were obtained. In addition, microscope was used to observe the inclusions inside samples. The results showed that there was a corresponding relationship between the absorption coefficient and the area of the inclusions. The larger the area of inclusions was, the more coefficient the THz absorption was, and the analysis of the influence of the area of inclusions on terahertz optical parameters provided a new and effective way for the study of fluid inclusions. The innovation of this paper is to use THz-TDS to quickly detect the change of the area of inclusions in crystals. The results indicates that terahertz time domain spectroscopy, as a new nondestructive testing method, has a unique advantage in the detection of inclusions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3689 (2017)
Study on Color Rendering of Light Communication Source Based on Multi-Chromatic LED
XU Yi-qi, BAI Ting-zhu, and TANG Yi
Visible Light Communication (VLC) is an emerging technology which combines LED lighting engineering and optical communication technique. In this article, we aim at the problems of bad color rendering, low luminous efficacy and non-adjustable color temperature of white LED lighting communication source. We did some reseVisible Light Communication (VLC) is an emerging technology which combines LED lighting engineering and optical communication technique. In this article, we aim at the problems of bad color rendering, low luminous efficacy and non-adjustable color temperature of white LED lighting communication source. We did some researches according to the multi-chromatic white LED communication theory. Meanwhile, we used the Gaussian distribution put forward by Yoshi as the spectral model of chromatic LED, and made use of the general color rendering index (Ra) which is recommended by CIE and the general color quality scale (Qa) recommended by National Institute of Standards and Technology (NIST) to evaluate the color rendering of light source. We adopted Genetic Algorithm to optimize single color temperature and adjustable color temperature scope 2 700 to 6 500 K based on principle that Ra and Qa are greater than 80 to optimize the best combination of spectra of adjustable color temperature light source. At last, according to the result of the experiment, we analyzed the relationship among the color rendering, luminous efficacy of radiation (LER) and adjustable color temperature of the light source. It turned out that tri-chromatic adjustable color temperature white LED’s peak wavelength combination which satisfies the best color rendering is 613 nm/541 nm/464 nm. Meanwhile, when the minimum of Ra and Qa are 81.2 and 81 respectively, it can meet the demand of lighting communication in the general situation. And the tetra-chromatic adjustable color temperature white LED’s peak wavelength combination which meets the best color rendering is 620 nm/562 nm/505 nm/449 nm. The minium of Ra and Qa are 96.7 and 92.2 at the same time. When in a spot which requires special lighting or higher communication rate, we should use tetra-chromatic LED white light as the lighting communication source. In the article, we have simulated the best spectral combination of LED. And it can provide some references for the design of visible communication light source used in the wide channels..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3693 (2017)
An On-Line Microfluidic Analysis System for Seawater Chemical Oxygen Demand Using Ozone Chemiluminescence
CAO Xuan, CHU Dong-zhi, LIU Yan, MA Ran, ZHANG Shu-wei, WU Ning, SHI Qian, and MA Hai-kuan
Chemical oxygen demand (COD) is a comprehensive index of organic pollutants in seawater, which is one of the most important items in marine environmental monitoring. The existing COD measurement methods are time-consuming and complex, which cannot meet the needs of online marine monitoring. This paper designs an integrChemical oxygen demand (COD) is a comprehensive index of organic pollutants in seawater, which is one of the most important items in marine environmental monitoring. The existing COD measurement methods are time-consuming and complex, which cannot meet the needs of online marine monitoring. This paper designs an integrating Microfluidic analysis system for COD using ozone chemiluminescence analysis. Different factors that influences on determination were optimized, including ozone and water flow rate, water temperature, salinity and filtration of the sample, etc. The experimental results have shown that this system can realize the analysis of 0.1~10 mg·L-1COD in seawater, the detection limit is 0.08 mg·L-1, and the measurement results are well consistent with the national standard method, Besides, it has the advantages of simple structure, short test time, meet the requirements of field analysis of seawater COD..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3698 (2017)
IR Spectra of Grease Optimization Based on Cuckoo Search
LI Xiao-he, FENG Xin, and XIA Yan-qiu
A selection method of infrared spectral based on cuckoo search was proposed to meet the classification of grease. The method would help to remove the infrared spectral region affected by noise and environment effectively, and realized the feature selection and dimension reduction processing of large spectral data. A moA selection method of infrared spectral based on cuckoo search was proposed to meet the classification of grease. The method would help to remove the infrared spectral region affected by noise and environment effectively, and realized the feature selection and dimension reduction processing of large spectral data. A more accurate and efficient classification model of grease was established by selecting the optimal spectral bands. Regarding the infrared spectrum data of three different types of greases as research targets in this paper, the Principal Component Analysis (PCA) was applied to compress the Infrared spectrum data of different bands and extracted the main components. Using the extracted main components of IR spectra and the grease thickener category as input and output respectively, an accuracy optimization training for the weight of principal component and parameter of classification kernel was conducted by Cuckoo Search (CS) to establish the classification prediction model. The classification accuracy of the model was tested and obtained the accuracy of the test results of model. In addition, it established the link between the infrared spectral band and the accuracy to get the optimal class identification model and optimal classification bands. The classification accuracy of the model was tested, and the result showed that the main feature trained and weighted by Cuckoo Search presents obvious clustering phenomenon. The classification kernel could be found and the type of grease could be classified accurately. Furthermore, it provided recommended bands and characteristic peaks for distinguishing different greases in the process of searching. The correct identification probability of the grease was improved from 94.44% for the classification model by whole band to 100% for filtered feature band, reducing the operation time and improving the search efficiency..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3703 (2017)
Study on Calibration Model Transfer for the Near Infrared Spectrum Based on Improved S/B Algorithm
XIN Xiao-wei, GONG Hui-li, DING Xiang-qian, ZENG Jian-xin, and LIU Qi-yan
In view of the limitations of S/B algorithm for nonlinear problems in calibration model transfer, based on the traditional S/B algorithm that uses linear fitting and partial least squares method for parameters, this paper improved it by introducing high power of variable and using Lagrange and Newton interpolation methIn view of the limitations of S/B algorithm for nonlinear problems in calibration model transfer, based on the traditional S/B algorithm that uses linear fitting and partial least squares method for parameters, this paper improved it by introducing high power of variable and using Lagrange and Newton interpolation method to seek undetermined coefficients and the interpolation polynomial to solve the nonlinear problem of the two sets of data. In order to verify the validity of the improved algorithm, this paper built a model for the master machine firstly and predicted the master and slave machine samples respectively, and then through the experiment data and the valuation index, it selected the best function relation to correct the model and finally predicted the unknown samples of the slave machine with the improved S/B algorithm and the traditional S/B algorithm. Experimental results showed that the gap is larger between reference value and the predicted value with master model directly, the predicted value with improved S/B algorithm was closer to the reference value than the traditional S/B algorithm. The improved S/B algorithm enhanced the accuracy of the prediction and solved the nonlinear problem of the traditional S/B algorithm. The algorithm based on Lagrange and Newton interpolation achieved better effect of model transfer and enhanced the generality of application in network modeling..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3709 (2017)
The Discrimination of Blackheart Pears Research Based on Visible/Near-Infrared Diffuse Transmission Spectrum On-Line Detector
LIU Yan-de, LI Yi-fan, GONG Zhi-yuan, and SUN Xu-dong
Pears which suffer from the main physiological disease as blackheart directly affected the export of pears, so fast and accurate identification of blackheart pears for pear export is of practical significance. Vis/NIR spectroscopy combining new online technique was proposed to identify exterior and interior properties Pears which suffer from the main physiological disease as blackheart directly affected the export of pears, so fast and accurate identification of blackheart pears for pear export is of practical significance. Vis/NIR spectroscopy combining new online technique was proposed to identify exterior and interior properties of objects in the present study. The purpose of this paper is to have a research on the feasibility of using visible/near-infrared diffuse transmission spectrum on-line detector to detect blackheart pears. 80 normal pears and 70 pears in disease are taked as modeling set. All samples were divided into the calibration set and prediction set for developing optimal results and assessing their performance. The visible/near-infrared diffuse transmission spectrum was collected under the speed of 5 pears per minute. Energy spectrum processed by the standard orthogonal transformation (SNV) and multiple scatter correction (MSC) respectively established the model of blackheart pears by partial least-squares discriminant model(DPLS) , peak area discriminant model (DPA) and PCA discriminant model(DPCA). 30 normal pears and 20 blackheart pears were taken as prediction set was used to evaluate the ability to predict. By comparison, the model of DPLS has the highest accuracy. All the blackheart pears were recognised correctly. The experiment shows that visible/near-infrared diffuse transmission spectrum with DPLS discriminant method realized the on-line detection of blackheart pears which provided technical support and reference for export trade of ‘Yali’ pear products. In comparison to destruction and time-consuming chemical methods, the results in the feasibility study may provide technical support and scientific reference in testing blackheart pears..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3714 (2017)
Quality Analysis with Near Infrared Spectroscopy in Perilla Seed
SHANG Zhi-wei, ZHAO Yun, SHEN Qi, WANG Xian-ping, XU Jing, YANG Sen, TIAN Shi-gang, and WEN He
To enhance quality breeding in Perilla frutescens, 250 lines of purple perillas collected from whole China were selected as material in the present study, combined with the technology of near infrared reflectance spectroscopy (NIRS) and partial least square method, NIRS Calibration Models for determination the content To enhance quality breeding in Perilla frutescens, 250 lines of purple perillas collected from whole China were selected as material in the present study, combined with the technology of near infrared reflectance spectroscopy (NIRS) and partial least square method, NIRS Calibration Models for determination the content of oil. Palmitate (C16∶0), stearic acid (C18∶0), oleic acid (C18∶1), linoleic acid (C18∶2) and a-linolenic acid (C18∶3) were established, respectively. The results showed that, the coefficients of determination of all the models for calibration (RSQ1) were 0.98, 0.91, 0.92, 0.92, 0.85, 0.93, respectively. In addition, the cross validation correlation coefficient (1-VR) were 0.97, 0.89, 0.89, 0.91, 0.85 and 0.91, respectively while the external validation correlation coefficient (RSQ) were 0.98, 0.91, 0.89, 0.90, 0.80 and 0.89, respectively. All models above have proven credible as the low value for Calibration standard error (SEC) were 0.99, 0.21, 0.1, 0.94, 0.81, 0.92, respectively; Cross validation standard error (SECV) were 1.16, 0.23, 0.11, 1.05, 0.92, 1.02, respectively; and Standard error of prediction (SEP) were 0.97, 0.21, 0.11, 1.12, 0.99, 1.14, respectively, suggesting that these calibration models are accurate, feasible and highly efficient. The establishment of these NIRS Calibration Models can provide guidance in resource development and quality breeding of Perilla frutescens L and specifically are of great significance for breeding varieties with high oil content..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3719 (2017)
Fabrication of Gold Nanoparticle Array Substrate by Chemical Replacement and Its Surface Enhanced Raman Scattering Properties
LI Yu, HUANG Xiao-ping, WANG Ying, HOU Yu-meng, CHEN Tao, ZHANG Pei-feng, HUANG Qiu-ying, and ZHAO Qing
Surface enhanced Raman Spectroscopy (SERS), as an analytical method, has the notable advantages of high sensitivity, high selectivity, high reproducibility and non-destructivity. It has been widely used in component characterization, environmental science, biomedicine, biosensors and other fields in the recent decades.Surface enhanced Raman Spectroscopy (SERS), as an analytical method, has the notable advantages of high sensitivity, high selectivity, high reproducibility and non-destructivity. It has been widely used in component characterization, environmental science, biomedicine, biosensors and other fields in the recent decades. Among them, gold and silver and other noble metal nanoparticles-based films have been widely used for SERS active substrates. A key factor in SERS is how to design and fabricate SERS substrates with large size, high enhancement, high repeatability, and recyclability. In general, the combined effect of the electromagnetic enhancement of the noble nanoparticles in a regular array and the enhancement of the electromagnetic coupling among the nanoparticles enhance the detection performance of the SERS substrate. However, the surface roughness of the nanostructures prepared by conventional methods such as photolithography and electron beam lithography is not enough. In this paper, we developed a method for the fabrication of gold nanoparticles tetragonal array pore structure by the combination of photolithography and chemical replacement methods. And, the electromagnetic enhancement properties SERS signal of the fabricated Au nanoparticles array substrates were investigated. The regular round holes array were etched with a tetragonal lattice structure on the silicon by photolithography. Then, the Fe film was deposited on the holes array by magnetron sputtering. After that, the chloroauric acid liquid membrane with a concentration of 1.893 8 mol·L-1 was spin-coated into the holes array on the substrate. The Fe film was then replaced with Au nanoparticles array in the iron holes array. Thus, the fabrication of SERS substrate with gold nanoparticles square lattice was completed. Based on the scanning electron microscopy (SEM) of the microstructure of the substrate, the gold nanoparticles deposited on the substrate were more and larger with the increasing reaction time between the iron film and the chloroauric acid solution. In order to verify the difference in nanostructure caused by different replacement time, the electromagnetic enhancement properties of the prepared gold nanoparticles array was characterized with SERS measurements. The SERS spectra of Au nanostructured substrate were measured by using rhodamine 6G (R6G) as probe molecule. The experimental results showed that the gold nanoparticles were more compact and order with a longer replacement time, and we can get the corresponding stronger SERS signal..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3725 (2017)
Design and Implementation of a Portable Rapid Detection Based on Plasmon-Enhanced Raman Spectroscopy
XUE Wen-dong, ZHENG Wen-kai, CHEN Jin-fu, HONG Yong-qiang, WANG Lei, ZENG Yong-ming, and LIU Guo-kun
The detection equipment for food safety, environmental pollution, drug safety, chemical warfare agents requires portable, fast and accurate detection. The traditional laboratory test methods can meet accurate requirement, but it is slow and cumbersome. This paper proposes a portable and rapid detection equipment based The detection equipment for food safety, environmental pollution, drug safety, chemical warfare agents requires portable, fast and accurate detection. The traditional laboratory test methods can meet accurate requirement, but it is slow and cumbersome. This paper proposes a portable and rapid detection equipment based on plasmon-enhanced Raman spectroscopy, which can realize rapid qualitative and accuracy detection. The equipment system is based on ARM embedded architecture. The UI interface and drivers are finished and the algorithms of auto calibration of Raman spectroscopy data and characteristic spectra fast recognition is designed. The spectrum database of standard subjects is constructed in this local equipment, which is classified according to the test required subject. The database includes a variety of substances in every subject, which contains standard and sample spectrum of different concentration. The algorithms of multiple substances identification and GPU hardware acceleration are designed and presented in this paper, which can detect mixed sample with more than twenty times faster then CPU soft calculate. A series of experiments are finished in the end to verify the algorithms and performance of the proposed equipment, such as wine, fruit juice and functional drinks getting from shop. The result meets the expectation with good sensitivity and reproducibility..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3730 (2017)
Study on Detection of Nafcillin Residues in Duck Meat Using Surface
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Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3736 (2017)
A Novel Method for Measuring Antimony Sulfide Content Based on Gaussian-Peak Fitting of Raman Spectroscopy
LI Yuan-ying, XU De-gang, GUI Wei-hua, YANG Chun-hua, and CAI Yao-yi
For measuring antimony sulfide by artificial chemical methods had many problems, such as complex operation and long detection time, a novel method for measuring antimony sulfide content rapidly based on Gaussian-peak fitting of Raman spectroscopy was proposed.The antimony samples were firstly characterized by Raman speFor measuring antimony sulfide by artificial chemical methods had many problems, such as complex operation and long detection time, a novel method for measuring antimony sulfide content rapidly based on Gaussian-peak fitting of Raman spectroscopy was proposed.The antimony samples were firstly characterized by Raman spectroscopy system to get their Raman spectroscopy, and Raw Raman spectra were pretreated including smoothing, background subtraction,spectrum selection and normalization. The mathematical model of single Gauss peak was established based on Gaussian peaks, peak area, half high width and peak position of the gauss curve.Then the Gaussian-peak fitting algorithm was proposed to fit Pretreated Raman spectra. The state transition algorithm was employed to get the optimization solution.The characteristic parameters were obtained to describe the information of Pretreated Raman spectra. The relational model between the spectra and antimony sulfide content was established by the combination of the Gaussian characteristic parameters and partial least squares regression method, so as to predict antimony sulfide content.It was important to verify this model. In the experiment, the calibration model was established by the training samples and was used to predict the testing samples. In order to test the correctness and extrapolation of the model, the proving samples were randomly selected from the training samples,and then the established model was used to predict the antimony content of them.The experimental results showed that applying Gaussian-peak fitting of Raman spectroscopy to measure antimony sulfide content was feasible, and the measuring process was more simple. It is suitable for rapid analysis of mineral composition..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3743 (2017)
Research on Optimal Near-Infrared Band Selection of Chlorophyll (SPAD) 3D Distribution about Rice Plant
ZHANG Jian, LI Yong, XIE Jing, and LI Zong-nan
Whether the chlorophyll 3D distribution of crop is obtained accurately really attracts attention of scientific research and production field, such as crop nutrition, cultivation and breeding. In this study, the research object is the rice plant. The transformed ordinary SLR camera with different near infrared filters wWhether the chlorophyll 3D distribution of crop is obtained accurately really attracts attention of scientific research and production field, such as crop nutrition, cultivation and breeding. In this study, the research object is the rice plant. The transformed ordinary SLR camera with different near infrared filters was used to acquire the multispectral images of rice plant in multi-view. Five kinds of vegetation indexes were calculated by combination image based on different bands and different channels. Then the optimal rice plant chlorophyll (SPAD value) prediction model was built between vegetation index and measured SPAD value. The research results showed that the prediction model with the quadratic function between GNDVI vegetation index and measured SPAD value can analyze chlorophyll content (SPAD value) of rice plant well, R2=0.758, RMSE=1.532. The GNDVI vegetation index was constructed by the R channel of near-infrared 760nm band and the G channel of visible light band. On this basis, the rice 3D model with texture information was built by multi-angle imaging 3D modeling method. Meanwhile, the optimal prediction model was applied to the integrated texture map of rice, and then the chlorophyll 3D distribution of rice was obtained. So rapid nondestructive detection of rice growth condition and chlorophyll nutrient situation can be realized..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3749 (2017)
Research on Fuel-Dilution Monitoring of Engine Lubricant by UV Fluorescence
GONG Xiao-long, TIAN Hong-xiang, SUN Yun-ling, HE Wei, LI Jing, and YANG Kun
Aiming at the condition monitoring problem of Diesel engine lubricating oil diluted by fuel, an experimental measuring apparatus was designed and completed to detect fluorescence intensity of oil samples by UV fluorometry. An UV LED with peak wavelength of 365 nm as emitting light source was chosen for exciting oil samAiming at the condition monitoring problem of Diesel engine lubricating oil diluted by fuel, an experimental measuring apparatus was designed and completed to detect fluorescence intensity of oil samples by UV fluorometry. An UV LED with peak wavelength of 365 nm as emitting light source was chosen for exciting oil sample to produce fluorescence. Ultraviolet light from emitting light source passed through a 400 nm optical low pass filter and went into oil samples in quartz colorimetric utensil. Oil samples excited by ultraviolet light may produced fluorescent light. Firstly, fluorescent light was filtered by 400 nm optical high pass filter. And then filtered fluorescent light was transformed into electric signal by the photoelectric sensor with the detection wavelength range from 400 to 800 nm. After amplified by measurement circuit , digital multimeter can be used to detect the fluorescent light intensity. The signal amplification and measurement system were designed. The combination of optical high and low pass filters can reduce the interference of the ultraviolet light emitted by the ultraviolet light source to the fluorescence intensity of oil samples. Fluorescence intensity data of seven oil samples with different fuel concentrations of 20.3 Wt.%, 10.0 Wt.%, 5.0 Wt.%, 2.5 Wt.%, 1.5 Wt.%, 0.7 Wt.% and 0.0 Wt.% were obtained by the experimental apparatus as the above mentioned. The fitting equation of fuel concentration with fluorescence intensity was acquired. Finally, the oil sample of 7.5 Wt.% diesel oil content was used to verify the accuracy of the method. The fluorescence intensity of verifying oil sample was measured by the experimental apparatus. The ration of fuel to oil was calculated by fitting equation. The results showed that the ration of fuel to oil relative error between the calculated and the actual was 0.5%. The accurate measurement of the dilution of lubricating oil by fuel under the laboratory condition was realized..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3758 (2017)
Effects of Different Substituents on Three Dimensional Fluorescence Properties of BTEX
WANG Bi, XI Hong-bo, ZHOU Yue-xi, CHEN Xue-min, and FU Xiao-yong
Three-dimensional fluorescence excitation-emission has been widely used to characterize dissolved organic matter in municipal wastewater, lakes and rivers. However, As one of the most important pollutants in petrochemical wastewater, the fluorescence characteristics of BTEX are rarely reported. In this paper, the fluorThree-dimensional fluorescence excitation-emission has been widely used to characterize dissolved organic matter in municipal wastewater, lakes and rivers. However, As one of the most important pollutants in petrochemical wastewater, the fluorescence characteristics of BTEX are rarely reported. In this paper, the fluorescence spectra of 14 typical BTEX at different concentrations were studied by F-7000 fluorescence spectrometer, and the relationship between the characteristics of three dimensional fluorescence spectra and their structural characteristics was discussed. The results showed that the structure, location and number of the substituents will affect the fluorescence characteristics of BTEX. Fluorescence peaks of benzene, toluene, ethyl-benzene, n-propylbenzene, cumene, xylene and 1,2,4-trimethyl benzene located at λех/λеm=205~215/280~295 nm. A fluorescence peak of styrene located at λех/λеm=230/345 nm. Two fluorescence peaks of phenol located at λех/λеm=220/300 nm, 270/295 nm. Two fluorescence peaks of aniline located at λех/λеm=235/335 nm, 280/335 nm. Chlorobenzene had a fluorescence peak locating at λех/λеm=215/290 nm, and no obvious fluorescence peaks of nitrobenzene were found. On the conditions of 1 mg·L-1 compared with benzene, the fluorescence intensity (FI) of toluene and ethylbenzene were increased by 10.62 and 9.45 times, with λех red shifting 5 nm, and intensity of fluorescence peaks of 1,2,4-trimethylbenzene, three kinds of xylene enhancement ratio were 5.49(above), 4.87, 2.14, 1.33. This is mainly due to the carbon atoms of substituents which directly connected with benzene-ring expanded the rigid plane. This showed the number of carbon atoms that non coplanar and coplanar of alkyl substituents in benzene will affect the fluorescence properties of matter. When the vinyl group of styrene expanded the rigid plane, the unsaturated double bond reduced the energy required for its excitation, the fluorescence intensity of 10 mg·L-1 ethylbenzene same with the concentration of 0.002 mg·L-1 styrene, the λех red shifting 20 nm compared with ethylbenzene relatively. Electron donating substituents, —OH and —NH2 can enhance the electron density of conjugated structure of the benzene-ring. The P orbital of n electron with the benzene formation of P—π conjugated system structure, rigid plane expansion, the intensity of fluorescence peaks increased with fluorescence spectrum redshift. On the contrary, the —NO2 and —Cl groups substances n→π* transition belonged to the forbidden transition, the less number of excited state molecules, while the intersystem crossing was stronger than π*→S1. Experimental results for weak fluorescence or no fluorescence were consistent with the theory..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3763 (2017)
Study on the Three-Dimensional Fluorescence Spectra of Oil Mixture and Its Composition Based on Tri-PLS Model
WANG Yu-tian, ZHANG Li-juan, ZHAO Xu, CHEN Yi-qiang, PAN Zhao, CAO Li-fang, XU Jing, YUAN Yuan-yuan, NIU Kai-zeng, and ZHANG Ya-ji
A new method which extend the partial least squares (PLS) method to three-dimensional (tri-PLS) and don’t need to care about the eigenvalue is presented to determinate the content of a variety of mineral oil mixture with overlapping spectra. This method is used to study the three-dimensional fluorescence spectra of theA new method which extend the partial least squares (PLS) method to three-dimensional (tri-PLS) and don’t need to care about the eigenvalue is presented to determinate the content of a variety of mineral oil mixture with overlapping spectra. This method is used to study the three-dimensional fluorescence spectra of the mixture of diesel, gasoline and kerosene. The 3D data matrix is constructed on the basis of the sample sequence, the excitation wavelength and the emission wavelength. The combination of 3D data matrix and the concentration matrix can be modeled by tri-PLS to predict the test samples.The experimental results show that the modeling precision of tri-PLS is superior to PARAFAC..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3771 (2017)
Detection of Carmine in Solution by Fluorescence Correlation Spectroscopy
GU Song, CHEN Guo-qing, ZHU Zhuo-wei, WU Ya-min, ZHU Chun, ZHAO Jin-chen, DU Jia-meng, and XI Liu-hua
20 samples of Carmine solution with different mass concentration were prepared and the emission spectra were measured by FLS920P fluorescence spectrometer. Experimental results showed that the optimum excitation wavelength and emission wavelength of Carmine solution were 300 and 440 nm respectively. The spectral data o20 samples of Carmine solution with different mass concentration were prepared and the emission spectra were measured by FLS920P fluorescence spectrometer. Experimental results showed that the optimum excitation wavelength and emission wavelength of Carmine solution were 300 and 440 nm respectively. The spectral data of ultrapure water were measured under the same condition and it was selected as the reference spectrum. The two-dimensional fluorescence correlation spectra were calculated under the perturbation of concentration. Sym8 wavelet based on the four-scale was selected for denoising. Partial least squares regression (PLSR) predictive models were built by using the synchronous correlation spectral data and auto correlation spectral data after the noise reduction. When Partial least square regression model was used combined with synchronous correlation spectral data for predicting the carmine contents in prediction set, the root mean square errors of prediction (RMSEP) was 0.414 μg·mL-1 and the coefficient correlation of actual values and predicted values was 99.863%. However, the model based on the Partial least squares regression model and auto correlation spectral data was better. The coefficient correlation of prediction set reached to 99.863%, and the root mean square errors of prediction (RMSEP) was 0.303 μg·mL-1. As can be seen from the results, the data of the autocorrelation spectra can effectively avoid information redundancy, and the effect is more reliable. The method simple operation does not rely on sample separation, , and can provide a new way of thinking for food safety testing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3776 (2017)
The Variable Nonlinear Absorption and Carrier Dynamics in GaN Thin Film under the Excitation of Femtosecond Pulses at Ultraviolet Wavelength
HOU Xue-shun, WANG Ying-wei, WANG Dao-wei, XIAO Si, HE Jun, and GU Bing
In this paper, by employing conventional femto-second Z-scan and pump-probe measurements, the nonlinear optical properties and photoexcited carrier dynamics relaxation time of the GaN film were investigated. Based on the oscillation transmittance spectrum of GaN film and linear optical theories, the linear absorption cIn this paper, by employing conventional femto-second Z-scan and pump-probe measurements, the nonlinear optical properties and photoexcited carrier dynamics relaxation time of the GaN film were investigated. Based on the oscillation transmittance spectrum of GaN film and linear optical theories, the linear absorption coefficients (α0), linear refractive index (n0) and optical bandgap (Eg) were obtained at near ultraviolet wavelength of 370 nm. Variable nonlinear absorption effects were observed with the open-aperture (OA) Z-scan experiments at different levels of laser excitation intensities. It is found that the GaN film shows saturable absorption at low intensities and reverse saturable absorption under the excitation of intense irradiances when the photon energy is close to the band gap of GaN film. It is believed that the observed nonlinear absorption originates from the one-photon absorption at low intensities whereas one-photon induced free carrier absorption dominates the nonlinear response at high intensities. With the carry out of closed-aperture (CA) Z-scan experiments, a large nonlinear refractive index in GaN was obtained, which was one orders of magnitude larger than that of conventional nonlinear media. To identify ultrafast carrier dynamic relaxation time of the observed nonlinearities and to get an insight of the physical mechanism, the cross-polarized femto-second degenerate pump-probe measurement was performed at a near-ultraviolet wavelength of 370 nm. The results indicate that the saturable absorption originates from the instantaneous one-photon absorption process at low intensities, while one-photon absorption induced free carrier absorption dominates the non-instantaneous nonlinear absorption process at high intensities with the free carriers dynamic relaxation time ~17 ps. This work provides significant insight to the application of GaN in nonlinear optical ultraviolet photonics devices and the understanding of nonlinear response mechanism in GaN films..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3781 (2017)
Vibrational Spectroscopic Characterization of the Co-Crystal and the Forming Condition between γ-Aminobutyric Acid and Benzoic Acid
ZHANG Qi, FANG Hong-xia, ZHANG Hui-li, QIN Dan, HONG Zhi, and DU Yong
Terahertz time-domain spectroscopy (THz-TDS), Fourier transform infrared (FTIR) and Fourier transform Raman (FT-Raman) spectroscopic techniques were utilized for the characterization and analysis of γ-aminobutyric acid (GABA), benzoic acid (BA), and their solvent/grinding co-crystals. All experimental results demonstraTerahertz time-domain spectroscopy (THz-TDS), Fourier transform infrared (FTIR) and Fourier transform Raman (FT-Raman) spectroscopic techniques were utilized for the characterization and analysis of γ-aminobutyric acid (GABA), benzoic acid (BA), and their solvent/grinding co-crystals. All experimental results demonstrated that GABA-BA co-crystal possessed unique spectroscopical characteristic compared with that of starting materials in THz-TDS, FTIR, FT-Raman spectra. THz-TDS results showed that similar absorption peaks of solvent and grinding co-crystals which formed between GABA and BA at 0.93, 1.33 and 1.57 THz can be observed. The result demonstrated that THz-TDS technique could effectively identify and characterize GABA, BA and its co-crystal, which was also a presentation of various substance that had different fingerprint characteristic features in THz range. To identify and affirm the crystal structure of GABA-BA co-crystal, FT-Raman and FTIR spectroscopic techniques were also employed by spectral assignment. Through the assignment of FTIR spectrum, it was confirmed that the first hydrogen bond of GABA-BA co-crystal was formed at place between amino H23 of GABA and carbonyl O1 of BA, while the second one was constituted by amino group N18 of GABA and hydroxyl group H15 of BA. Some Raman scattered peaked, such as 576, 886, 1 250, 1 283, 1 337, 1 423 and 1 470 cm-1 which belonged to bending vibrations of —CH2, —NH2 in GABA, disappeared upon the formation of GABA-BA co-crystal, demonstrating the atom nitrogen (N18) in GABA can be served as hydrogen bond acceptor. So the Raman result verified the validity of above FTIR deduction, which confirmed the crystal structure of GABA-BA co-crystal, Furthermore, formation of co-crystal was impacted by pH value of solvent. With the solvent condition of 2.00≤pH≤7.20, the GABA-BA co-crystal can be stably formed. This work provides experimental and theoretical benchmark to discriminate and identify the crystal structure of co-crystal formed between active ingredients and co-crystal formers and crystalline formation conditions in the solid state with THz-TDS and FT-Raman techniques..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3786 (2017)
Synthesis and Characterization of 4,8,15,22-Tetra［3,3-Bis(P-hydroxyphenyl) Phthalide］ Phthalocyanines
XIA Dao-cheng, LI Jie-jun, LI Wan-cheng, FENG Feng, and LI Dan
Due to the widely application of Pcs in the fields, such as the communication, medical treatment, chemical industry and so on, therefore, it have been a hot research topic over several decades by scientists. However, along with the human society development and the progress in science and technology, the new phthalocyaDue to the widely application of Pcs in the fields, such as the communication, medical treatment, chemical industry and so on, therefore, it have been a hot research topic over several decades by scientists. However, along with the human society development and the progress in science and technology, the new phthalocyanine with novle characteristics is still the goal of the scientists. In this dissertion, the synthetic methods of the phthlocyanine are improved. The 4,8,15,22-tetra［3,3-bis(p-hydroxyphenyl)phthalide］ phthalocyanines were synthesized and characterized. Using 3-［3,3-bis(p-hydroxyphenyl) phthalide］ 2,3-dicyanonitrobenzene and copper acetate monohydrate, dehydrate nicle acetate as starting materials in n-pentanol, DBU as a catalyst, to synthesize 4,8,15,22-tetra［3,3-bis(p-hydroxyphenyl) phthalide］ phthalocyanines. The phthalocyanines were characterized, then the results proved that compounds were the target products. And the relevant ultraviolet spectrum, fluorescence spectroscopy and optical luminescence spectroscopy properties were studied..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3793 (2017)
Novel Spectral COD Measurement Method Based on Identification of Water Samples
L Meng, HU Ying-tian, GAO Ya, and WANG Xiao-ping
Chemical oxygen demand (COD) is one of the important indicators of water quality. The COD measurement method based on UV/Vis absorption spectra has been widely used because of its advantages of high speed, real time results, void of reagents, and pollution-free. Different functional groups have different characteristicChemical oxygen demand (COD) is one of the important indicators of water quality. The COD measurement method based on UV/Vis absorption spectra has been widely used because of its advantages of high speed, real time results, void of reagents, and pollution-free. Different functional groups have different characteristic absorption spectra. In the application of the method to water samples with a stable solution, high COD measurement accuracy can be achieved by building a precise “UV/Vis Absorbance(Auv)-COD” computational model. However, when the method is used for water samples with variable components, the measurement precision is low, limiting its applicability. This study proposes a new method based on dynamic identification of water sample type. The LM-BP neural network algorithm is used for the identification of water samples in this paper. And the morphology characteristics of the absorption spectra were used as the input parameters of water sample identification models. In the application of COD measurement, the water sample’s absorption spectra have a time correlation. Based on the foundation laid by traditional spectrum identification techniques, the algorithm was optimized in accordance with the characteristics of COD measurement. The concept of historical data queue and historical identification factor was introduced into LM-BP artificial neural network and forms the cascaded network structure. Experiments show that the method exhibited better robustness and higher accuracy than traditional algorithms, because the cascaded network is relatively more able to adapt the characteristics of the COD measurement. The test yielded a 98% identification accuracy rate, which can provide a technical guarantee for the application of spectral COD measurement in a complex environment. In this paper, the sensor structure and the proposed algorithm are simple as well, which can be used in the portable instrument with limited resource. The UV/Vis-COD measurement method based on the water sample identification algorithm can achieve improved accuracy compared to the traditional method, which calculates all water sample types with the same computational model. The proposed method is expected to solve the problem that traditional UV/Vis-COD measurement methods face regarding difficulties adapting when applied to complex environments while still achieving high COD measurement accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3797 (2017)
Based on Optical Properties of Chromophoric Dissolved Organic Matter in the Monitoring of Coastal Eutrophication
CHEN Yong, WEI Jia, LIN Cai, XU Jing, SUN Xiu-wu, and LIN Hui
Eutrophication is an important ecological environment problem in estuary and coastal area. The traditional monitoring technology for eutrophication is laborious and time-consuming, so it is difficult to realize the real-time and on-site monitoring and then rapid evaluate the eutrophication degree. Based on the investigEutrophication is an important ecological environment problem in estuary and coastal area. The traditional monitoring technology for eutrophication is laborious and time-consuming, so it is difficult to realize the real-time and on-site monitoring and then rapid evaluate the eutrophication degree. Based on the investigation of chromophoric dissolved organic matter(CDOM) and other environmental parameters in Xiamen Bay in February, May, August and from October to November 2009, the feasibility of using CDOM optical properties to retrieve eutrophication parameters (COD、 TN and TP) in coastal environment was evaluated. CDOM showed large spatial and seasonal changes in Xiamen Bay, with the highest CDOM abundance occurring in the Jiulong River Estuary. The terrestrial input and phytoplankton production were the main sources of CDOM in Xiamen Bay. The empirical formula to estimate the CDOM abundance in seawater was then established by using the salinity and chlorophyll-a data. The correlation coefficient of this empirical formula was 0.96 and the relative errors between fitted values and measured values for CDOM of different survey stations were (11.1%±0.71%. There were high correlations between CDOM absorption coefficient and fluorescence components with chemical oxygen demand(COD), total nitrogen(TN), total phosphorus(TP) in all seasons, with the highest correlations in spring and summer, and the lowest in winter. Combined with the above results, instead of the data including COD, TN and TP got only through manual samplings and laboratory analysis, the data of salinity and chlorophyll-a could be provided by water quality automatic monitoring system and CDOM data got by above empirical formula, so it is possible to realize the rapid monitoring and evaluation for the degree of coastal eutrophication by using in situ buoy system with CDOM sensor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3803 (2017)
Sensitivity Analysis of Spectral Band Adjustment Factors For GF-1/WFV Sensor Cross-Calibration
ZHOU Ke, LIU Li, YU Tao, GU Xing-fa, ZHENG Feng-bin, and ZANG Wen-qian
Affected by the components aging and the space environment changing, the radiation performance of the first satellite , GaoFen series (GF-1) changes since it has been launched. The orbit calibration can track the performance changing during the sensor’s lifetime. Cross calibration using the high radiometric calibrationAffected by the components aging and the space environment changing, the radiation performance of the first satellite , GaoFen series (GF-1) changes since it has been launched. The orbit calibration can track the performance changing during the sensor’s lifetime. Cross calibration using the high radiometric calibration precision can improve the calibration frequency and accuracy. Spectral band adjustment factors (SBAF) are important factors in cross calibration. Terra / MODIS is selected as reference sensor, GF-1 / WFV as target sensor, and the SBAF can be calculated based on the in situ measurement spectral data at Dunhuang radiometric calibration site, considering the observation angle, spectral response, atmospheric conditions and surface properties. Time series cross calibration coefficients can be obtained according to the SBAF. GF-1/WFV apparent radiances are obtained by the cross calibration coefficients, while Terra/MODIS apparent radiances are obtained by the digital number and calibration coefficients. The relative deviations of apparent radiances between the two sensor’s are compared by analysis. It shows that SBAF in different bands has same trends; The SBAF above 0.9 are 53.1%, 75%, 81.2%, 93.8% for blue, green, red, near-infrared bands, respectively; Time series calibration coefficients and SBAF are negatively correlated and the relative deviations of apparent radiances are smaller while the SBAF are closer to 1..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3809 (2017)
Synthesis of ZnO/PAMAM G5.0 Nano Composite and Its Application on the Enhancement of Cyanoacrylate Pre-Treated Fingermark
WANG Yuan-feng, SONG Zhao-zhao, DUAN Wei, WANG Wen-long, and DU Ran
In order to improve the sensitivity, specificity and safety of latent fingermark reagent based on nano technique, we designed the structure of ZnO/PAMAM G5.0 nano composites, explored its synthesis method, examined the fluorescent property of the newly developed nano composites and investigated its application on the eIn order to improve the sensitivity, specificity and safety of latent fingermark reagent based on nano technique, we designed the structure of ZnO/PAMAM G5.0 nano composites, explored its synthesis method, examined the fluorescent property of the newly developed nano composites and investigated its application on the enhancement of cyanoacrylate pre-treated fingermark. The results indicated that ZnO nano particles could be on-site synthesized under the control of PAMAM G5.0 dendrimer template. ZnO/PAMAM G5.0 nano composites emitted blue light under the excitation of long UV light. When the concentration ratios of Zn2+ and PAMAM dendrimers were between 10～100, the fluorescent intensity of ZnO/PAMAM G5.0 nano composites changed with respect to the increase of the concentration ratio. The highest fluorescent intensity could be reached when the concentration ratio was set at 60. Cyanoacrylate pre-treated fingermark could be enhanced by the amidation reaction between ZnO/PAMAM G5.0 nano composites and the ester terminal groups of cyanoacrylate polymer. The newly developed ZnO/PAMAM G5.0 nano composites obtain the fluorescent characteristics through non-toxic quantum dots and strengthen latent the fingermark development based on routine developing method. It will play an important role in the development of latent fingermark reagent based on nano technique in the near future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3814 (2017)
The Research on Spectroscopy and Locality Characteristics of the Nephrite Jade from Hechi, in Guangxi
JIANG Cui, LAI Jun-tao, YIN Zuo-wei, and ZHU Zhen-zhen
The nephrite which has been found in Hechi, Guangxi in the couple of years, in various colors like white, greenish white, rarely dark green and black, is gaining a growing popularity. Compared with those located in other places, the Hechi nephrite presents a greasy luster which has a dry and mostly opaque texture withoThe nephrite which has been found in Hechi, Guangxi in the couple of years, in various colors like white, greenish white, rarely dark green and black, is gaining a growing popularity. Compared with those located in other places, the Hechi nephrite presents a greasy luster which has a dry and mostly opaque texture without “water lines”, the inclusions of which are band patterns in white or grayish white colors and dendritic patterns in brownish yellow and dark colors. That’s why it is named “dendritic jade” in market. The samples were tested by standard gemological methods, Raman spectroscopy, X-ray diffraction (XRD), and other techniques. The research results show that the RI of them is from 1.616 to 1.632, an average hydrostatic S. G. 2.895, inert under UV. The Raman spectra of jade part and white band are consistent with the standard Raman spectrum of nephrites. The main peaks are mainly 225, 370, 676, 1 029 and 3 677 cm-1. Despite the results of the Raman and XRD showing that the white bands are nephrites, the band parts show different color and transparency with naked eyes because of different display patterns and sizes of the grains in the bands. Through test and calculation, the degree of crystallinity of research samples is 0.963 on average which is bigger than that of Xinjiang 0.843 on average and similar to that of Qinghai 0.96 on average. This means nephrites in this era crystallized well so as to make the mineral grains bigger, which indicates that the characteristics of slow cooling crystallization process. Because the crystallinity of the samples is good and grains are more irregular at the same time, the overall transparency of jade decreased. The value IBe/ISi of LIBS test on nephrites located in Xinjiang is 0.003～0.008, Qinghai 0, Liaoning 0.004～0.006, Korea 0.1～0.16, Russia 0.03～0.05, while that of Hechi in Guangxi is 0, similar to that of Qinghai..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3819 (2017)
Feature Extraction and Classification of Animal Blood Spectra with Support Vector Machine
LU Peng-fei, FAN Ya, ZHOU Lin-hua, QIAN Jun, LIU Lin-na, ZHAO Si-yan, KONG Zhi-feng, and GAO Bin
It is of great significance to study how to use spectral detection technology and data mining technology to realize the accurate identification and classification of different animal blood spectral data, and it has not yet seen relevant complete research conclusions and methods on animal blood identification and classiIt is of great significance to study how to use spectral detection technology and data mining technology to realize the accurate identification and classification of different animal blood spectral data, and it has not yet seen relevant complete research conclusions and methods on animal blood identification and classification. Therefore, the authors collected fluorescence spectra data of four kinds of animals, including pigeon, chicken, mouse and sheep. Based on the soft threshold denoising method of wavelet transform, the original spectral data were denoised, and the 717 original features were determined. Following the approach of “Distinguish statistic” proposed by the authors, 717 original features were extracted into 2 finally input features. Based on support vector machine, the whole blood solution of different animals were 100% recognized, while the red cell blood solution of different animals were 94.69%~99.12% correctly recognized. Finally, the Monte Carlo cross validation revealed that the method used in this paperhad a great generalization ability for whole blood solution of different animals, which can play an important role in the import and export inspection, food safety, medicine and other fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3828 (2017)
Application of Hyperspectral Technology for the Determination of the Solid Concentration of the Anaerobic Digestion
YE Hui, LI Xiao-li, YU Ke-qiang, XIA Yi-hua, ZHANG Chu, and HE Yong
Timely monitoring variations of the solid concentration plays a significant role in the stability control of the anaerobic digestion process. In this study, infrared hyperspectral technology coupled with chemometrics methods is applied to detect the amount of solid concentration in which process water hyacinth and riceTimely monitoring variations of the solid concentration plays a significant role in the stability control of the anaerobic digestion process. In this study, infrared hyperspectral technology coupled with chemometrics methods is applied to detect the amount of solid concentration in which process water hyacinth and rice straw are co-digested. Compared to the traditional way (2540G APHA, 1990) , it is faster and non-destructive. Firstly, the hyperspectral information of fermentation broth is obtained by application of infrared hyperspectral and the spectroscopy data is pretreated by utilizing moving average smoothing (MAS), and then adaptive weighted sampling competition (CARS), random frog (RF) and successive projections algorithm (SPA) are applied to extract characteristic wavelengths. Finally the calibration models of total solid (TS) and volatile solid (VS) are established based on the extracted characteristic wavelengths, partial least square (PLS) and least square-support vector machine (LS-SVM), Which are taken to predict the solid concentration of fermentation broth. The study indicates that SPA-LS-SVM model achieves optimal result, among which the root mean square error prediction (RMSEP) and correlation efficient (R) of the total solid concentration are respectively 0.005 8 and 0.841; the root mean square error prediction and correlation efficient of the volatile solid concentration are respectively 0.004 1 and 0.874. The study shows that it is feasible to utilize infrared hyperspectral combined with chemometrics methods for prediction of the solid concentration of the fermentation broth, and it can provide a theoretic and practical basis for setting up a spectral sensor to detect the solid concentration of anaerobic digestion process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3833 (2017)
Hyperspectral Inversion of Heavy Metal Content in Coal Gangue Filling Reclamation Land
XU Liang-ji, LI Qing-qing, ZHU Xiao-mei, and LIU Shu-guang
The research object of the paper is, based on the Huainan Chuangda coal gangue filling reclamation experiment area, to analyze soil heavy metals (Cu, As, Cr) with the traditional sampling method. Reflectance spectra of soil samples measured by Analytical Spectral Devices FiSpec4, spectral features are extracted, and thThe research object of the paper is, based on the Huainan Chuangda coal gangue filling reclamation experiment area, to analyze soil heavy metals (Cu, As, Cr) with the traditional sampling method. Reflectance spectra of soil samples measured by Analytical Spectral Devices FiSpec4, spectral features are extracted, and the spectra are averaged with the first order differential, the second order differential transformation, and the inverse logarithmic transformation, etc. Correlation analysis of spectral characteristic parameters and heavy metal content in soil is conducted, therefore, the selection of the relevant bands is related to the relevant factors. Multivariate stepwise regression analysis, partial least squares regression and artificial neural network are used to establish the prediction model of soil heavy metals by using soil spectral reflectance. The experimental results show that the spectral bands of the differential transformation are significantly correlated with the content of heavy metals. For heavy metal Cu and Cr, the artificial neural network model of the first order differential spectrum is the best prediction model and the partial least squares regression model of the two order differential spectra of heavy metal elements is obtained by the best prediction results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3839 (2017)
Relationship Between Hyperspectral Parameters of Winter Wheat Canopy and Plant Height Components under Late Frost Injury
SHI Ping, WU Yong-feng, HU Xin, L Guo-hua, REN De-chao, and SONG Ji-qing
After late frost injury, the physiological and ecological aspects of winter wheat were changed, among which the change of plant height was the most significant. In this research, four plant height components, including plant height, ear length, peduncle length, and penultimate internode length, as well as 15 hyperspectAfter late frost injury, the physiological and ecological aspects of winter wheat were changed, among which the change of plant height was the most significant. In this research, four plant height components, including plant height, ear length, peduncle length, and penultimate internode length, as well as 15 hyperspectral parameters, namely red edge position and the red edge amplitude, etc were obtained. The change rate plant height components, which has the best correlation with the hyperspectral parameters were selected by correlation analysis, and then were used to establish stepwise regression model. The results showed that only the change rate of plant height was significantly correlated with the hyperspectral parameters in both two experiments in 2013 and 2014. After the two experimental data were combined, the change rates of spike length, peduncle length and the penultimate internode length were also significantly correlated. Comprehensively considering the Adj. R2 and the significance level (Sig. ), it can be seen that the best fitting model is the change rate of ear length, followed by the plant height, the peduncle length and the penultimate internode length. Comparing the RMSE of the model, it can be seen that the change rate of peduncle length got the highest prediction precision. The results of this study provide a good reference for the prediction of wheat plant height by hyperspectral parameters under freezing stress conditions. The results are of great significance to the study of the changes of plant height elements in winter wheat under low temperature stress..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3845 (2017)
Experimental Investigation on the Electron Temperature of Laser-Induced Ti Plasmas
YAO Hong-bing, YANG Feng-xiao, YUAN Dong-qing, TONG Yan-qun, YANG Zhao, CONG Jia-wei, Emmanuel Asamoah, and WANG Cheng
Laser pulse which was produced by Nd∶YAG pulse laser, with a wavelength of 1 064 nm and pulse width of 12 ns, was used to shock the Ti target under the condition of room temperature and atmospheric pressure. By changing the laser energy (180, 230 and 280 mJ) and adjusting the delay time through a digital delay generatoLaser pulse which was produced by Nd∶YAG pulse laser, with a wavelength of 1 064 nm and pulse width of 12 ns, was used to shock the Ti target under the condition of room temperature and atmospheric pressure. By changing the laser energy (180, 230 and 280 mJ) and adjusting the delay time through a digital delay generator of DG645, a series of plasma characteristic spectral lines of Ti alloy were obtained by a mechelle grating spectrometer in the time range of 0~500 ns. By analyzing the spectrum, 9 different TiⅠ and TiⅡ plasma lines can be found. It was shown that under the experimental conditions, the Ti target can fully absorb the energy to ionization and the ion spectral line has different evolution rate. The Saha-Boltzmann method was used to calculate and analyze the electron temperature of Ti plasma. The experimental results showed that at the same delay time, the greater of laser energy was used, the stronger of relative intensity of the line was obtained, and the higher of electron temperature could be induced. When the variable quantity of laser energy increased, the variable quantity of spectral line relative intensity will increase. In the delay time of 0~150 ns, the plasma electron temperature and the spectrum line relative intensity of the three kinds of laser energy decrease rapidly with the increase of the delay time, of which the electron temperature and spectrum line intensity decrease faster under laser energy of 280 mJ. During 150 to 250 ns, the electron temperature and spectrum line intensity have a slow rise with the increase of delay time, and the rising rate of the plasma electron temperature and the spectral line intensity were faster when laser energy is 180 mJ. In the range of 250 to 500 ns, the electron temperature and the spectrum line intensity of the three kinds of laser energy decrease slowly with the increase of the delay time..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3851 (2017)
Characteristics of Light Emission and Radicals Formed by Microwave Discharge Electrolysis of an Aqueous Solution
ZHAO Xiao-tong, SUN Bing, ZHU Xiao-mei, YAN Zhi-yu, LIU Yong-jun, and LIU Hui
A variety of active substances can be produced during discharge in liquid, in which hydroxyl radical (OH), hydrogen radical (H) is considered as main active species leading to liquid chemical reaction. However, it is difficult to measure them due to its characteristics of short activity and short life; especially it isA variety of active substances can be produced during discharge in liquid, in which hydroxyl radical (OH), hydrogen radical (H) is considered as main active species leading to liquid chemical reaction. However, it is difficult to measure them due to its characteristics of short activity and short life; especially it is more difficult to conduct quantitative measurement due to the lack of standard samples. In contrast to the indirect measurement of direct capture, the optical method of measuring free radicals is a direct measurement method, which is characterized by instantaneous on-line measurement that allows immediate data acquisition and time and spatial distribution measurements. In order to study the free radical properties of microwave discharge in water, the active substances produced by microwave discharge were investigated by optical emission spectroscopy. The effects of microwave power and internal pressure on the relative spectral intensities of OH radicals were investigated. The spatial distribution of OH radicals in the plasma was observed. At the same time, the electron excitation temperature was estimated. The experimental results showed that a large amount of OH, H, O radicals could be produced by microwave discharge in water, in which OH radicals had the strongest relative spectral intensity and showed a tendency to increase with the increase of microwave power; but were rapidly weakened with the increase of internal pressure. Free radicals based on OH radicals were mainly produced in the vicinity of the tip of the electrode. At the same time, the microwave excitation temperature of the microwave plasma in water was about 0.33×104 K..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3855 (2017)
Multi-Element Analysis of Wild Chinese Honeylocust Fruit by Inductively Coupled Plasma Tandem Mass Spectrometry (ICP-MS/MS)
JIANG Bo, HUANG Jian-hua, and LIU Wei
An analysis method was developed to detect trace elements in Chinese Honeylocust Fruit by using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). All samples were microwave digested by using (HNO3+H2O2+HCl). In the MS/MS mode, the polyatomic interferences were eliminated by the utilization of O2 mass shiAn analysis method was developed to detect trace elements in Chinese Honeylocust Fruit by using inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). All samples were microwave digested by using (HNO3+H2O2+HCl). In the MS/MS mode, the polyatomic interferences were eliminated by the utilization of O2 mass shift, O2 on-mass, and NH3 mass shift with O2 or NH3 in the collision/reaction cell of the ICP-MS/MS. The analytical results of proposed method were validated by analysis of the national standard reference samples of green tea (GBW10052) and celery (GBW10048), which showed good agreement with the certified values, RSD≤7.8%. Furthermore, 12 trace elements (V, Cr, Co, Cu, Zn, Fe, Mn, Ni, As, Cd, Hg, and Pb) in these samples collected from Yunnan and Chongqing Wuling Mountain, were detected by proposed analyzed method. The detection limits of the analytes were in the range of 0.29～21.36 ng·L-1. The analytical results showed that Fe and Zn elements were rich in these wild samples, while heavy elements in these samples were lower than limitation standard of Chinese pharmacopoeia. This study can be used to estimate the trace element and quality of wild honey locust. Also, this study can provide scientific methods and data for the safety assessment and regulation of trace elements in Chinese Honeylocust Fruit..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3859 (2017)
Quantitative Analysis of Trace O Concentration in SF6 with Laser-Induced Breakdown Spectroscopy
YANG Wen-bin, and LI Bin-cheng
Sulfur hexafluoride (SF6) is widely used in gas-insulated high-voltage equipments due to its excellent insulation and arc extinguishing performance. However, when impurities such as trace water and oxygen are present in SF6, the by-products, which are formed due to equipment faults and partial discharge, can react withSulfur hexafluoride (SF6) is widely used in gas-insulated high-voltage equipments due to its excellent insulation and arc extinguishing performance. However, when impurities such as trace water and oxygen are present in SF6, the by-products, which are formed due to equipment faults and partial discharge, can react with these impuriti to form stable sulfur oxyfluorides. The equipment insulation performance can be degraded significantly by those stable sulfur oxyfluorides, causing threat to the safety of the power system. The detection and analysis of the impurities such as water, oxygen and decompositions in SF6 are therefore of great importance. In this paper, laser-induced breakdown spectroscopy is employed to measure trace O in SF6. CaF2 is used as window material to solve the degradation of the excitation energy caused by the corrosion of the window material by SF6 decompositions, to eliminate the pollution problem caused by the reaction between the window material and the breakdown products of SF6 gas, and to reduce the change of plasma state caused by the change of excitation condition. By correcting the spectral baseline with an iterative wavelet transform and suppressing the noise with a wavelet transform with soft thresholding, a limit of detection of 38ppm is achieved from the experimental calibration curve. Furthermore, a quantitative model based on partial least squares (PLS) is developed to achieve better stability and precision..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3865 (2017)
Comparative Analysis of Chemometrics Method on Heavy Metal Detection in Soil with Laser-Induced Breakdown Spectroscopy
XIANG Li-rong, MA Zhi-hong, ZHAO Xin-yu, LIU Fei, HE Yong, and FENG Lei
A large number of farm lands are contaminated by heavy metals in the process of industrialization and urbanization. Precise detection of heavy metals in soil offers valid reference for prevention and recovery of heavy metals in the field. In this research, Laser induced breakdown spectroscopy (LIBS) and chemometrics meA large number of farm lands are contaminated by heavy metals in the process of industrialization and urbanization. Precise detection of heavy metals in soil offers valid reference for prevention and recovery of heavy metals in the field. In this research, Laser induced breakdown spectroscopy (LIBS) and chemometrics methods were employed to conduct quantitative analysis of heavy metals Pb and Cd in soil. Based on the pollution extent, soil samples with 15 concentration gradients of Pb and Cd were manually made up. Then, the LIBS emission lines of all soil samples were collected firstly. In order to eliminate errors and noise of spectral data, preprocessing methods called removal of abnormal data and normalization were used. Then, characteristic lines and spectral regions of Pb and Cd were determined based on our LIBS spectra and Atomic Spectra Database (ASD) of National Institute of Standards and Technology (NIST). Quantity regression models based on multiple linear regression (MLR), partial least squares regression (PLSR), least squares support vector machine (LS-SVM) and back propagation-artificial neural network (BP-ANN) were set up and their results were compared. As a result, models based on non-linear methods (LS-SVM and BP-ANN) offered a promising results than the linear methods of MLR and PLSR. The probable reason was that non-linear methods had an advantage to deal with matrix effects of soil automatically. The results indicated that LIBS coupled with multiple chemometrics methods provided a brand-new analysis approach for heavy metals accurate detection in soil and it could be considered as an effective theoretical foundation of making protection and recovery decision for soil contaminated by heavy metals..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3871 (2017)
AAS Determination of Sb in Pretreated Copper Anode Slime by Alkali Fusion Method
DONG Zai-zheng, WANG Nan, LI Xue-jiao, TONG Xiao-min, WANG Lin, and YANG Hong-ying
Copper anode smile is an important by-product of metallurgical industry which contains a variety of precious metals and valuable metals, so that its comprehensive recycling and utilization is increasingly concerned. It is difficult to use conventional method to dissolve the Sb in pretreated residue of copper anode slimCopper anode smile is an important by-product of metallurgical industry which contains a variety of precious metals and valuable metals, so that its comprehensive recycling and utilization is increasingly concerned. It is difficult to use conventional method to dissolve the Sb in pretreated residue of copper anode slime (enriched slag). Therefore, it is necessary to develop an accurate and simple method to realize the quantitative analysis of Sb. Here, a comprehensive analysis method was developed for the chemical composition, phase and microstructure of the enriched slag by means of X-ray fluorescence spectroscopy, X-ray diffraction and field emission scanning electron microscopy by using alkali fusion procedure. The analysis results showed that the chemical composition and physical structure of the enriched slag are complex, and its components are chemical stable and intergrowth closely. Sb exists in the form of high state antimony acid salt with a stable structure. The samples were digested by Na2O2 fusion method, and the standard series of synthetic standard samples were synthesized. The content of Sb in the enriched slag by flame AAS was 8.23% with the relative standard deviation of 0.97%, the detection limit of 0.072% and the recoveries of 94.9%～99.2%. Here, the enriched slag can be completely dissolved by this simple method, which does not require the use of special reagents and instruments. Because the synthetic standard sample is similar to the actual sample, the interference of coexisting substances caused by the complicated chemical composition can be eliminated. This method with high sensitivity and good accuracy in comparison experiment, can be used for the quantitative determination of Sb in pretreated copper anode slime..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3877 (2017)
A Spectrophotometric Detecting Method of Trace Cobalt under High Concentrated Zinc Solution
ZHU Hong-qiu, GONG Juan, LI Yong-gang, and CHEN Jun-ming
In the process of detecting the concentration of trace cobalt ions in the high-concentration zinc solution by spectrophotometry, because chemical properties of Zn(Ⅱ) and Co(Ⅱ) are similar and the concentration of base ion is too high. Those facts lead to the overlap of the spectrum of Co(Ⅱ) and Zn(Ⅱ) which most of the In the process of detecting the concentration of trace cobalt ions in the high-concentration zinc solution by spectrophotometry, because chemical properties of Zn(Ⅱ) and Co(Ⅱ) are similar and the concentration of base ion is too high. Those facts lead to the overlap of the spectrum of Co(Ⅱ) and Zn(Ⅱ) which most of the spectral signals of Co (Ⅱ) are masked by the spectral signals of Zn(Ⅱ), strong nonlinearity of absorbance and concentration, and poor additivity in mixture solution in the partial wavelength. Thus it is difficult to determine the concentration of cobalt by the whole band information. In this paper, the interval-correlation coefficient-PLS is proposed to select the wavelength of the ultraviolet and visible spectrum of the solution and then establishes the absorbance-concentration model. Firstly, experiment was designed to obtain spectrum of Zn(Ⅱ) and Co(Ⅱ) mixture; Secondly , evaluation indicator-the predicted root mean square error was used to extract and optimize feature from full-spectrum data, which reduced masking effect of the high-concentration Zn(Ⅱ) and removed blank information.; Then the correlation coefficient method was adapted on the analysis of absorbance matrix in sensitive region of cobalt to select wavelength points detailed. The points selected finally could retain cobalt sensitivity and linearity in maximum degree; Finally, the partial least squares(PLS) model was established by the selected wavelength point to compute the concentration of Co(Ⅱ). The proposed method was compared with full band PLS, iPLS, MCUVE-PLS and CARS-PLS, and the result showed that with the proposed method the number of selected wavelength points respectively decreased 89.1%, 40%, 72.3% and 81.7%, and accuracy under this model respectively increased 64.6％, 33.3%, 38.7% and 24.3% compared with other methods in the background of the high concentration of zinc solution. The maximum relative error was only 5.45 % and the average relative error was 2.21%. The proposed method can properly resolve the problem of detecting trace cobalt ion concentration in high-concentrations zinc solution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3882 (2017)
The Determination and Characterization of Main Components in Patchouli Based on the XRF, PXRD and FTIR
ZHANG Li-juan, WANG Shu-tao, YANG Zhe, and CHENG Peng-fei
The quality control and evaluation of Chinese herbal medicine is essential in the development of medical modernization. In this paper, aiming at the objectivity and high-precision of identifying Chinese herbals’ characteristics, which can lead to the realization of quality control of Chinese medicinal materials, the XRThe quality control and evaluation of Chinese herbal medicine is essential in the development of medical modernization. In this paper, aiming at the objectivity and high-precision of identifying Chinese herbals’ characteristics, which can lead to the realization of quality control of Chinese medicinal materials, the XRF, PXRD and FTIR, based on which a novel method to identify the main components and origin of Chinese herbal medicine was established, were used to measure the main component and micro-structure of patchouli. The experimental results have shown that, there are a variety of inorganic elements, such as K, Ca, Cl, Si, P et al, and the unique elemental characteristic spectrum is part of material basis for Patchouli forming good efficacy of Chinese medicinal materials. Patchouli contains large amounts of crystalline substance and a small number of amorphous substance, in which Ca exists in state of CaC2O4·H2O, and the content of the crystal material is proportional to the strength of the sharp peak. FTIR spectrum reflects the infrared absorption of the various components of tested sample. After analyzing of FTIR spectral peak it provides information of chemical component substances such as alcohol, flavonoids and calcium oxalate. Comqared with existing analysis methods, this method combining XRF, PXRD and FTIR objectively reveals that the main components and microstructure of patchouli from the elements, atoms and molecules, which overcome this one-sidedness of the using some way respectively. And this method avoids the change of the inherent component because that the complex sample pretreatment has the advantages of fast , simple andgood reproducibility and is easy to accept. It might provide a new method for the quality control and evaluation of patchouli and other Chinese herbal medicine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3889 (2017)
XRD Diffraction Characteristics and Microscopic Morphology of Carbonates in Saline-Alkaline Soil from the Shore of the Aibi Lake
ZHANG Fang, ZHANG Wei-jie, DING Yan-yan, ZHAO Zhong-guo, and GE Hao
Based on the XRD, SEM and EDS methods, this paper discovers the distribution and forms of carbonate in saline-alkaline soils from the shore of The Abi Lake in Xinjiang, under the depositional environment of modern salt lake. The results showed that the primary minerals in the saline soil are mainly quartz and feldspar,Based on the XRD, SEM and EDS methods, this paper discovers the distribution and forms of carbonate in saline-alkaline soils from the shore of The Abi Lake in Xinjiang, under the depositional environment of modern salt lake. The results showed that the primary minerals in the saline soil are mainly quartz and feldspar, and the clay minerals are mainly chlorite and illite. The order of weathering of soil minerals is: north>western>eastern. west sample of modern salt lake chemical deposition is the most significant, northern sample is very strong biological weathering process. XRD method and volume method respectively measured were very significant positive correlation between carbonate content, determination coefficient R2 is 0.640 9. When the salinity soil contains more chlorite, the potential of carbon sink can be significantly improved. Meanwhile, the identification error of carbonate relative content by XRD method is increased and the shape of diffraction peak becomes complex, which results in an obvious underestimation of the carbonate content. underestimate the reason may be related to diffuse scattering caused by high organic matter content increased and high clay mineral content makes mass is associated with increased with isomorphism phenomena. The soils from western and northern areas were severely eroded, and the gypsum is dispersed or radially distributed between the calcite crystals in the form of fibrous or long columnar crystals. The calcite is in the form of heterogeneous nucleation or in the form of granules or flakes on the surface of other minerals or substrates, which indicates the characteristics of secondary carbonate morphology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3893 (2017)
Lithium Abundance of 17 Young Nearby Stars: High Resolution Spectrograph Observation with Lijiang 1.8 m Telescope
XING Li-feng, and CHANG Liang
A high resolution echelle spectra for a sample of 18 stars, mainly composed of young solar type stars, is presented in this paper. Observations of these stars have been carried out with the 1.8 m Optical Telescope located at the Lijiang station of the Yunnan Astronomical Observatories, Chinese Academy of Science (YAOC)A high resolution echelle spectra for a sample of 18 stars, mainly composed of young solar type stars, is presented in this paper. Observations of these stars have been carried out with the 1.8 m Optical Telescope located at the Lijiang station of the Yunnan Astronomical Observatories, Chinese Academy of Science (YAOC). The high-resolution and high signal-to-noise ratio spectra of the observations suggest that the reformation of the Coude Echelle Spectrograph attached to the 2.16 m telescope at the Xinglong station of the National Astronomical Observatories, Chinese Academy of Science (NAOC) was successful. Based on these observations, the LiⅠ λ 670.8 nm equivalent widths and the lithium abundances of 17 nearby young stars were derived The empirical relationship for estimating the surface flux in the band pass k3925 to k3975 was applied to compute the CaⅡ emission flux. Using the lithium abundances and the CaⅡ emission flux, the relationship between the Li abundances and the CaⅡ emission flux was investigated . A clear correlation between the lithium abundances and the CaⅡ emission flux is found: as the CaⅡ emission flux became stronger, the lithium abundance decreases in our sample stars. Taking into account of the main features of the rotational evolution of low-mass stars: on the Pre-Main-Sequence, low-mass stars appear to spin up rapidly, and reach very rapid rotation rates at the Zero-Age-Main-Sequence(ZAMS); after ZAMS, the rotation period of star increase with increasing age (spin down). Our results support the chromospherically active solar-type star has high lithium abundances and the rotation-activity relation of young stars..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3900 (2017)
Research of Clustering for LAMOST Early M Type Spectra
LIU Jie, PANG Jing-chang, WU Ming-lei, LIU Cong, WEI Peng, YI Zhen-ping, and LIU Meng
Large-scale spectral survey projects such as LAMOST produce a great deal of valuable research data, and how to effectively analyze the data of this magnitude is a current research hotspot. Clustering algorithm is a kind of unsupervised machine learning algorithm, which makes the clustering algorithm deal with the data Large-scale spectral survey projects such as LAMOST produce a great deal of valuable research data, and how to effectively analyze the data of this magnitude is a current research hotspot. Clustering algorithm is a kind of unsupervised machine learning algorithm, which makes the clustering algorithm deal with the data without knowledge of the domain, and internal law and structure will be found out. Stellar spectral clustering is a very important work in astronomical data processing. It mainly classifies the mass spectral survey data according to its physical and chemical properties. In this paper, we use a variety of clustering algorithms such as K-Means, Bisecting K-Means and OPTICS to do clustering analysis for the early M-type stellar data in LAMOST survey. The performance of these algorithms on the early M-type stellar data is also discussed. In this paper, the performance of the Euclidean distance, the Manhattan distance, the residual distribution distance for the three clustering algorithms are studied, and the clustering algorithm depends on the distance measurement algorithm. The experimental results show that: (1) The clustering algorithm can well analyze the spectral data of the early M-type dwarf star, and the cluster data produced by clustering is very good with the MK classification. (2) The performance of the three different clustering algorithms is different, and Bisecting K-Means has more advantages in stellar spectral subdivision. (3) In the cluster at the same time it will produce some small number of clusters, and some rare celestial bodies can be found from these clusters. OPTICS is relatively suitable for finding rare objects..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3904 (2017)
Optical Design of Large Relief Large Relative Apertureand High Resolution Modified Dyson Imaging Spectrometer
LIU Xiang-lei, LIU Yang-yang, FANG Yu, PEI Lin-lin, and L Qun-bo
We present the optical design of modified Dyson imaging spectrometer (MDIS), to get a fast F# and high resolution ability under the large focal planerelief, ameniscus lens and a plano-aspherical lenswere added into classical Dyson construction consisting of Dyson lens and concave grate. Firstly, MDIS can solve the defeWe present the optical design of modified Dyson imaging spectrometer (MDIS), to get a fast F# and high resolution ability under the large focal planerelief, ameniscus lens and a plano-aspherical lenswere added into classical Dyson construction consisting of Dyson lens and concave grate. Firstly, MDIS can solve the defects that the detector and slit are hard to be arranged in a classical Dyson imaging spectrometer. Moreover, under the large focal plane reliefconstraintsimposed by assembling and work environment, MDIS is an F/1.8 and spectral resolution 0.45 nmdesign, covering the spectral range 0.38～0.9 μm. Secondly, to our knowledge this is the first time that a fast and high spectral resolution Dyson design is under 12 mm focal plane relief. Although the simplicityof the classical Dyson construction is weakened, MDIS has a very good practical value. Specifically, MDIS can realize the function of a relay imaging system with a 12 mm slit length as well as 250 mm×92 mm×92 mm system size. The design result showed that image quality close to the diffraction limit has been obtained. That is, the value of MTF at all working wavelengths in all fields was greater than 0.7 at 100 lp·mm-1; the maximum of the keystone and the smile at all working wavelengths in all fields were respectively 1 and 0.7 μm. Finally, we can say MDIS provides an effective way to detect atmospheric remotesensing , agriculture, forestry and marine organismsinformation and so on..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3908 (2017)
An Allotype Double H-V Depolarizer for Hyperfine Spectrometer
TANG Qian, GUO Li-xin, and ZHAO Bao-chang
High precision atmospheric detection spectrometers are widely used, because the sunlight would be polarized while passing the atmosphere and that could reduce detecting precision of the devices. There are many efforts on removing this influence. An allotype double H-V(Horizontal-Vertical) depolarizer is proposed, and iHigh precision atmospheric detection spectrometers are widely used, because the sunlight would be polarized while passing the atmosphere and that could reduce detecting precision of the devices. There are many efforts on removing this influence. An allotype double H-V(Horizontal-Vertical) depolarizer is proposed, and it is equipped on hyperfine spectrometer used for atmosphere detecting in UV. Because the birefringence structure of crystals could eliminate the polarization, they are always chosen for depolarizers. Essentially, the birefringence of depolarizer can induce depolarization and double-imaging at the same time. The difference between traditional structure and the allotype is the inequality of the wedge angles of two sub H-Vs. There are different double-imaging distances in the spectrum dimension and the spatial dimension. So the contradiction between high-depolarization and high-imaging quality could be resolved. This paper will describe the design and analyzed the result. Depolarization is better than 98.8% and distance of the double-imaging is just 8.7% in the spatial dimension..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3913 (2017)
Planar Waveguide-Based Luminescent Solar Concentrator in PMMA Doped with Rhodamine 6G
LI Xing, ZHANG Chun-mei, WU Wei-xia, ZHANG Ao, LUO Yun-peng, DENG Rui-jiang, ZOU Cheng, and MENG Tao
Photovoltaic power generation is one of the most efficient ways to utilize solar energy. In this paper, a type of planar waveguide-based luminescent solar concentrator with a surface area of 50 mm×50 mm and a height of 5 mm is fabricated by coating a layer of Rhodamine 6G-doped PMMA on a clean PMMA substrate. The Photovoltaic power generation is one of the most efficient ways to utilize solar energy. In this paper, a type of planar waveguide-based luminescent solar concentrator with a surface area of 50 mm×50 mm and a height of 5 mm is fabricated by coating a layer of Rhodamine 6G-doped PMMA on a clean PMMA substrate. The thickness of the Rhodamine 6G-doped PMMA layer is 32 m. The influence of the concentration of Rhodamine 6G on the concentration ratio and photovoltaic properties has also been investigated. The results have shown that the concentration ratio and the photovoltaic properties reach 0.45 and 0.49%, respectively when the concentration of of Rhodamine 6G is 0.250%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3920 (2017)
Research on Visible-Near Infrared Spectral Characterization of Purplish Soil Contaminated with Petroleum Hydrocarbon and Estimation of Pollutant Content
YIN Wen-qi, CHEN Zhi-li, JIAO Yu-wei, LIU Hong-tao, and LIU Qiang
Hyperspectral remote sensing technology is an effective method to monitor petroleum contamination. It is mainly used in offshore oil spill, while few study has been focusing on soil petroleum-hydrocarbon contamination. In this case, due to the shortage of research on soil petroleum-hydrocarbon contamination, three kindHyperspectral remote sensing technology is an effective method to monitor petroleum contamination. It is mainly used in offshore oil spill, while few study has been focusing on soil petroleum-hydrocarbon contamination. In this case, due to the shortage of research on soil petroleum-hydrocarbon contamination, three kinds of petroleum hydrocarbons are selected, including diesel, gasoline and motor oil, to characterize the absorption features of petroleum hydrocarbons in spectra yielded from contaminated purplish soils in condition of different types and different concentrations of petroleum hydrocarbons and extract the spectral absorption characteristic band of soil contaminated by petroleum hydrocarbon. Based on this, seven kinds of spectral transformations and correlation analysis were conducted to select the most sensitive spectral variables with petroleum hydrocarbon content. The estimation model was established via univariate regression and multiple stepwise linear regression (SMLR) respectively and verified ultimately. The results show that the spectral signatures of soil contaminated by diesel, motor oil and gasoline are in the vicinity of 1 200, 1 700 and 2 300 nm, and the absorption depth is shown as follows: motor oil>gasoline>diesel. Multiple stepwise linear regression method is superior to univariate regression method. The coefficients of determination (R2) of diesel, motor oil and gasoline are greater than 0.95. Moreover, the root mean square error of calibration (RMSEC) is less than 0.47 and the root mean square error of validation (RMSEC) is less than 0.56, which demonstrates higher estimation accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3924 (2017)
A Stepped Mirror Based Temporally and Spatially Modulated Imaging Fourier Transform Spectrometer:Principle and Data Processing
GAO Jian-hua, LIANG Jing-qiu, L Jin-guang, LIANG Zhong-zhu, QIN Yu-xin, and WANG Wei-biao
This manuscript introduces the principle and data processing method of a stepped mirror based temporally and spatially modulated imaging Fourier transform spectrometer. The instrument substitutes the moving mirror, which is widely used in a Michelson interferometer, with a stepped mirror to realize static interference.This manuscript introduces the principle and data processing method of a stepped mirror based temporally and spatially modulated imaging Fourier transform spectrometer. The instrument substitutes the moving mirror, which is widely used in a Michelson interferometer, with a stepped mirror to realize static interference. A scanning mirror is placed in front of the first imaging system to make the target image on different sub-mirrors to get different optical path differences. Light emitted from the target propagate through the scanning mirror and the first imaging system to focus on the stepped mirror and the plane mirror to form two primary images. The primary images are then reflected by the stepped and plane mirrors to propagate through the second imaging system and finally image on the detector. Since there are optical path differences between the stepped mirror and the plane mirror, the image captured by the detector would have the two-dimensional spatial and one-dimensional spectral information of the target. The scanning interval of the scanning mirror is set to be 0.095° according to the parameters of the stepped mirror and the optical system. Image stitching and spectrum reconstruction are done using the experimental data cube. A polar Hough transform based image cutting method is proposed to deal with the sub-mirror width difference problem in image cutting. To mitigate the discontinuity line effect in the panorama, the image is transformed to the HSI space to adjust its intensity. After interferogram dimension reduction, direct current offset removal, interferogram addressing, apodization, phase correction, Fourier transform and spectral resolution enhancement, the spectrum is reconstructed and its resolution is 194 cm-1, which is better than the designed value (250 cm-1)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3932 (2017)
The Study for Formation Mechanism of Spectral Red Edge of Green Vegetation
WANG Jing, LIU Lang, LI Cheng, XIANG Teng-fei, ZHENG Shun-li, DING Shi-bing, and LIU Pan-jin
Red edge of green vegetation is caused by strong chlorophyll absorption, and its position shifts to long-wavelength with the increase of chlorophyll. Chlorophyll, including chlorophyll a and b, belongs to porphyrin derivative in molecular structure. Therefore, it is found that the other synthesized porphyrin may also iRed edge of green vegetation is caused by strong chlorophyll absorption, and its position shifts to long-wavelength with the increase of chlorophyll. Chlorophyll, including chlorophyll a and b, belongs to porphyrin derivative in molecular structure. Therefore, it is found that the other synthesized porphyrin may also is of red edge property. In order to study the formation mechanism of red edge, a serious of porphyrins and metalloporphyrins including Tetraphenylporphyrin(TPP), Tetrakis-(4-methoxyphenyl)porphyrin(TMPP), Tetrakis-(4-sulfophenyl) porphyrin (Na4TPPS), Tetrapyridylporphin (TPyP), Tetramethylporphyrin (TMP), Tetrakis-(4-methoxyphenyl)porphyrin zinc (ZnTMPP) and Tetrakis-(4-methoxyphenyl) porphyrin copper (CuTMPP) were synthesized and characterized by UV-Vis-NIR, FT-IR and 1H NMR. With systematically analysis of their UV-Vis spectrum (absorption, transmittance and solid reflectance), we found that porphyrins or metalloporphyrins can also cause the red edge similar to chlorophyll. The red edge is caused by strong Q band absorption of porphyrins, and red edge is right slope of absorptionvalley in their UV-Vis transmittance spectrum. The red edge position is related to the concentration of porphyrin, the substituents on the porphyrin ring, and the center metal of metalloporphyrins. Red edge position will shift to short-wavelength when phenylic H is substituted by electron-withdrawing group, and shift to long-wavelength when substituted by electron-donating group as well as increasing concentration of porphyrins. The change of substituent group in porphyrins ring is influence more obviously than the change of substituent groups in benzene ring of TPP. The number of Q bands will decrease when metal ions insert to porphyrin ring. Therefore, red edge positionwill be strongly influenced by metalloporphyrins..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3940 (2017)
Fluorescent Sensor for Melamine Based on Its Copper Complex Interrupted of AT-dsDNA Copper Nanoparticles
OU Li-juan, SUN Ai-ming, L Xiao-long, CHEN Si-yu, WANG Ling-yun, and LUO Jian-xin
A novel turn-off strategy was developed for the melamine (Mel) detection based on melamine-Cu conjugate and subsequent interrupted the formation of AT-dsDNA copper nanoparticles (AT-dsDNA CuNPs). The coordination of melamine to copper cannot make the reduction of Cu2+ to Cu0 enough in the AT24-CuNPs synthesis process, A novel turn-off strategy was developed for the melamine (Mel) detection based on melamine-Cu conjugate and subsequent interrupted the formation of AT-dsDNA copper nanoparticles (AT-dsDNA CuNPs). The coordination of melamine to copper cannot make the reduction of Cu2+ to Cu0 enough in the AT24-CuNPs synthesis process, and thereby results in the fluorescence intensity of CuNPs decreasing. Under the optimum conditions, the concentration of melamine showed a good linear relation with the fluorescence response of CuNPs in the range of 1~150 μmol·L-1. The detection limit was 0.5 μmol·L-1. Furthermore, good recoveries were obtained while the proposed method was applied to the analysis of melamine in milk samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3947 (2017)
New Method for Obtaining Full-Stokes Parameters of High-Spectral Polarization Imaging System
Li Xiao, Liu Shun, Wang Zhibin, Xue Peng, Zhang Rui, Wang Yaoli, and Jing Ning
Taking into account of the slow measuring speed, low measuring accuracy and complex system structure of the existing Stokes parameters acquisition method , a new acquisition method of full-Stokes parameters in double Liquid Crystal Variable Retarder (LCVR) and Acousto-Optical Tunable Filter (AOTF) combining spectral poTaking into account of the slow measuring speed, low measuring accuracy and complex system structure of the existing Stokes parameters acquisition method , a new acquisition method of full-Stokes parameters in double Liquid Crystal Variable Retarder (LCVR) and Acousto-Optical Tunable Filter (AOTF) combining spectral polarization imaging system is established. Based on the working principle of AOTF and LCVR, this paper has explored the basic detection principles of the system before a new method for fast acquisition of full-Stokes parameters is proposed. According to polarization analysis, fixed control voltage is selected as the basis, in which four fixed voltages are selected as the control voltages of LCVR, and two identical LCVR are controlled at the same time to complete phase modulation of optical waves. The Stokes parameters can be obtained with four groups of phase delay which are plunging the same. Besides, a LCVR controller is designed to stabilize the output square wave whose root mean square is 0 to +8.72 V. Then, its calibration is carried out in order to realize precise modulation of different optical waves. Finally, an experimental prototype is set up to test the target, with three polarizing plates P1, P2 and P3 whose polarization directions being 0, 90 and 45 degrees respectively as the targets of polarization measurement. The full-Stokes parameter figures with a wavelength of 632 nm is obtained; paper painted with red, green and blue lines and the angle of 30 degrees are used as the target of spectral measurement, spectral imaging on 71 channels of 400~750 nm spectral range (spectral bandwidth of 5 nm), the spectrum curves of red, green, blue are acquired which accordant with their theoretical spectral graphs. The results show that not only all the Stokes parameters can be obtained quickly and accurately with the system, but also the structure of system is simplified and the imaging quality is improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3953 (2017)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 1 (2017)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 12, 3961 (2017)
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