Journals >Spectroscopy and Spectral Analysis
Contents
2016
Volume: 36 Issue 12
59 Article(s)
Export citation format
Research Article
Analysis of Theory and Performance of Multi Layer Graphene Nanoribbons Photodetector
LIU Hai-yue, NIU Yan-xiong, YIN Yi-heng, DING Ming, YANG Bi-yao, and LIU Shuai
Multilayer graphene, with wide absorption spectrum and unique photoelectric properties, is an ideal material to make the next generation of photoelectric detector. Taking graphene interband tunneling theory as the foundation, a photoelectric detector model with the structure of multilayer graphene nanoribbons was propoMultilayer graphene, with wide absorption spectrum and unique photoelectric properties, is an ideal material to make the next generation of photoelectric detector. Taking graphene interband tunneling theory as the foundation, a photoelectric detector model with the structure of multilayer graphene nanoribbons was proposed. Nanoribbons which contacted with source and drain electrode at the end were sandwiched between the semiconductor substrate and the top and back gate. Using this model, a photoelectric conversion mechanism of multilayer graphene nanoribbon detector was established. It discussed the working principle of the detector at different top gate voltage, studied the relationship between the source-drain current and the incident light energy, researched the influence of the bias voltage, the length of depletion and the values of band gap on the dark current, and analyzed the change of detector responsibility and detectivity with the incident light energy under the different parameters. The results show that, the responsibility of detector increases with the layers of nanoribbons, and are affected by the band gap, the length of depletion and the bias voltage. The maximum responsibility up to 103 A·W-1; By limiting on the top gate voltage, the band gap and other variables can control the dark current of system and increase the detectivity, the detectivity up to a maximum value of 109 cm Hz1/2·W-1. The structure of multilayer graphene nanoribbons can enhance the absorption of the incident light, improve the sensitivity of the detector and the detection capability of weak light, and realize the detection from THz to far infrared wavelength of incident light. The detection performance is far better than that of many quantum structures and narrow-band semiconductor structure of photoelectric detector..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3811 (2016)
Haze Spectral Analysis and Detection Algorithm Using Satellite Remote Sensing Data
GE Wei, CHEN Liang-fu, SI Yi-dan, GE Qiang, FAN Meng, and LI Shen-shen
Frequent occurring of haze pollution events and high fine particulate matter (PM2.5) concentration in China have attracted more and more attention in the world. Satellite remote sensing can be used to characterize the air pollution. However, haze is usually misidentified as fog, thin cloud or bright surface in NASA’s MFrequent occurring of haze pollution events and high fine particulate matter (PM2.5) concentration in China have attracted more and more attention in the world. Satellite remote sensing can be used to characterize the air pollution. However, haze is usually misidentified as fog, thin cloud or bright surface in NASA’s Moderate Resolution Imaging Spectrometer (MODIS) cloud and clear days’ aerosol products, and the retrieval of its optical properties is not included in MODIS cloud detection and dark target algorithm. This approach first studies the spectral characters of cloud, fog, haze, and land cover pixels. Second, following the previous cloud detection and aerosol retrieval literatures, a threshold algorithm is developed to distinguish haze from other pixels based on MODIS multi-band apparent reflectance and brightness temperature. This algorithm is used to detect the haze distribution over North China Plain in 2008 spring and summer. Our result shows a good agreement with the true-color satellite images, which enhances MODIS’s ability to monitor the severe air pollution episodes. In addition, the high AOD data from Beijing and Xiang Aerosol Robotic NETwork (AERONET) sites indicate nearly 80% haze days are detected by our approach. Finally, we analyze the errors and uncertainties in haze detection algorithm, and put forward the potential improvements..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3817 (2016)
Research Progress of Far Field Light Scattering Spectra of Single Gold Nanorods
YANG Yu-dong
The far-field optical technology of single gold-nanorod(AuNR) has attracted a great deal of attention in recent years. Because of special local surface plasmon resonance (LSPR) property, AuNR particles have high conductivity of optical signals localized on the surface from physical or chemical irritants. The mechanism,The far-field optical technology of single gold-nanorod(AuNR) has attracted a great deal of attention in recent years. Because of special local surface plasmon resonance (LSPR) property, AuNR particles have high conductivity of optical signals localized on the surface from physical or chemical irritants. The mechanism, application, progress and novel optical characteristics of AuNRs in optical detection and spectroscopy method are being reviewed in our work. The paper describes an overall introduction as follows: (1)various related technologies on AuNR scattered spectrum, including dark-field technology, homodyne and heterodyne technology, photonic crystal technology, spatial modulation, polarization modulation technology,etc; (2) the properties of AuNR scattered spectrum, including spectral line-shape functions, effects of line-width and substrate, comparison of theoretical and experimental spectrums,etc; (3) the development of related spectrum technologies in recent years. The paper focuses on the method of far-field optical scattering based on LSPR and mainly discusses the linear method based on AuNRs, such as direct and indirect scattering detection method. We also put emphasis upon studying the importance of medium environment (for example, substrate, the molecules combined on surface and other nanomaterials) and the influence on scattered spectrum and the extinction rate. Of particular note is the quantitative method and correlation studies of AuNR’s surface and morphology, and its character is that most of the methods are compared with theoretical model and experiments in terms of accuracy. The combination of the experiments and theoretical tools can be used to explain the optical properties of single gold-nanorod particle in detail.
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3825 (2016)
Simulation of Concentration Measurement of SO2, NO2 and Particles Simultaneously by Differential Optical Absorption Spectroscopy
ZOU Jie-shu, WANG fei, YAN jian-hua, and CEN Ke-fa
Our daily life is disturbed seriously by the haze weather now. It is very important to measure the haze composition quantificationally. The main composition of haze is SO2, NO2 and particles. At present, the research of measuring gas and particle simultaneously is rare relatively. This paper use differential optical abOur daily life is disturbed seriously by the haze weather now. It is very important to measure the haze composition quantificationally. The main composition of haze is SO2, NO2 and particles. At present, the research of measuring gas and particle simultaneously is rare relatively. This paper use differential optical absorption spectroscopy (DOAS) to simulate the concentration measurement of gas and particle simultaneously and obtain some meaningful results. Absorption spectral of many groups of different concentration of SO2, NO2 and particle were simulated, and each concentration was inverted by DOAS. In the first group of single component, the concentration change from 100 to 1 000 ppm, the inverted error of SO2 is not greater than 0.17%, and which is 0.64% for NO2. When the diameter of particle change from 100 to 500 nm, the inverted error is not greater than 2.08%. In the second group of multiple gases, when the concentration ratio of SO2 and NO2 is at the range of 1∶10 and 5∶1, the error of SO2 is not bigger than 8%, and 5% for NO2, relatively. But when the concentration of SO2 is 10 times than NO2, the error is higher than 10% for NO2. In the third group of gas and particle, the error of gas concentration is lower than 10%, but the concentration error of particle is depended on signal to noise ratio (SNR) greatly. When SNR is higher than 40 dB, error can lower than 10% and when SNR is lower than 30dB, the error is bigger than 20%. From these results, we can see that DOAS can measurement SO2, NO2 and particles simultaneously effectively, and can applied to measure and analyze haze composition. However, when the absorption strength of the gases is different greatly, the strong absorption gas influent the weak absorption gas largely. And the SNR is lower, the error of inverted particle concentration increased greatly. The solution of these problems need better filtering and noise reduction method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3830 (2016)
Tissue Intrinsic Fluorescence Spectrum Recovering Based on Diffusion Theory
LIU Yong, ZHANG Yuan-zhi, HOU Hua-yi, ZHU Ling, WANG An, and WANG Yi-kun
Tissue intrinsic fluorescence spectrum refers to the fluorescence that is not impaired by tissue absorption and scattering which has the ability to reflect tissue biochemical properties. In order to reduce the influence of tissue absorption and scattering properties on tissue fluorescence spectrum, and then recover tisTissue intrinsic fluorescence spectrum refers to the fluorescence that is not impaired by tissue absorption and scattering which has the ability to reflect tissue biochemical properties. In order to reduce the influence of tissue absorption and scattering properties on tissue fluorescence spectrum, and then recover tissue intrinsic fluorescence spectrum, a tissue spectrum detection system based on fiber-optic probe was developed for the measurement of tissue fluorescence spectrum and diffusion reflectance spectrum at the same place. On the other hand, diffusion theory was introduced to extract the tissue physiological parameters from the measurement tissue diffusion reflectance spectrum, which included blood volume fraction, oxyhemoglobin saturation, melanin content, reduce scattering coefficient at 500 nm and the ratio of rayleigh scattering and the total scattering. Then tissue optical parameters in visible wavelengths were calculated. According to the tissue optical parameters and measured tissue diffusion spectrum, the intrinsic fluorescence spectrum was recovered from the measured fluorescence. Based on this, clinical trials were conducted to measure human skin fluorescence spectrum and diffusion reflectance spectrum, and then to recover skin intrinsic fluorescence spectrum. Finally, the accumulation of Advanced Glycation End products (AGE) in human skin was evaluated and the probability of diabetes mellitus was predicted. The result shows that the sensitivity and specificity were 69% and 0.75% respectively, when the measured fluorescent was used to screening diabetes mellitus. At the same specificity, the sensitivity was 90% when the recovered intrinsic fluorescence was employed to screening diabetes mellitus..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3836 (2016)
Studies on the Analytical Potential Energies for Partial Electronic States of Li2 with Variational Algebraic Energy Consistent Method
ZHANG Chun-guo, FAN Qun-chao, SUN Wei-guo, FAN Zhi-xiang, and ZHANG YI
The full vibrational spectra especially those high-lying vibrational energies in the dissociation region of four specific electronic states 13Δg, 33Σ+g, 13Σ－g and b3Πu have been obtained by using the improved variational algebraic method (VAM). The analytical potential energy functions (APEFs) of these electronic stateThe full vibrational spectra especially those high-lying vibrational energies in the dissociation region of four specific electronic states 13Δg, 33Σ+g, 13Σ－g and b3Πu have been obtained by using the improved variational algebraic method (VAM). The analytical potential energy functions (APEFs) of these electronic states are also determined with corresponding adjustable parameter λ by using the variational algebraic energy consistent method (VAECM) based on the VAM vibrational spectra. The full vibrational energies, vibrational spectroscopic constants, force constants fn, and expansion coefficients an of the VAECM potential are also tabulated for each electronic state in this study. The results show that the VAECM analytical potentials are superior to some other widely used analytical ones, and do not have the unphysical tiny barriers existing in the precious AECM potentials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3842 (2016)
Trace Moisture Measurement with 5.2 μm Quantum Cascade Laser Based Continuous-Wave Cavity Ring-Down Spectroscopy
ZHOU Sheng, HAN Yan-ling, and LI Bin-cheng
Trace moisture concentration in high-purity gases is an important parameter in semiconductor manufacturing because many manufacturing processes are sensitive to moisture even on the level of parts per billion by volume (ppbv). Detection of trace moisture in mid-infrared spectral region is beneficial due to more abundanTrace moisture concentration in high-purity gases is an important parameter in semiconductor manufacturing because many manufacturing processes are sensitive to moisture even on the level of parts per billion by volume (ppbv). Detection of trace moisture in mid-infrared spectral region is beneficial due to more abundant and stronger spectral lines in this region. Recently, Quantum cascade lasers (QCLs) with high output power, narrow line-width, and high reliability have been developing rapidly and have become promising light sources for sensitive spectroscopic measurements. By employing a 5.2 μm external-cavity tunable quantum cascade laser, a continuous-wave cavity ring-down spectroscopy (CRDS) experimental setup is established and applied to detect trace moisture in high-purity nitrogen gas. In the experiment, the CRDS signal is averaged to improve the detection sensitivity, and the optimal averaging number is determined by Allan variance calculation to be 602. For trace moisture detection, the absorption cross-section of H2O in the spectral range between 1 905 and 1 925 cm-1 is simulated according to the HITRAN database and the optimal detection spectral line is chosen. Detected at 1 918 cm-1 absorption line at 296 K temperature and 1 atm pressure, the measured moisture concentration is in good agreement with the nominal value, and the minimum detectable moisture concentration of 24.8 ppbv is achieved when cavity mirrors with reflectance of 99.93% are used. The experimental results show that mid-infrared cavity ring-down spectroscopy technique has great potential in a wide variety of applications, such as industrial production control, environmental monitoring and health diagnosis, etc..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3848 (2016)
Experimental Investigation on the Electron Temperature of Laser-Induced Mg Plasmas
YAO Hong-bing, NI Wen-qiang, YUAN Dong-qing, YANG Zhao, and LI Qiang
A series of plasma characteristic spectral lines of Mg alloy were obtained under nanosecond laser shock produced by a pulsed Nd∶YAG laser (1 064 nm, maximum energy 500 mJ), which was taken under standard atmospheric pressure and at room temperature. Results indicated that the evolutionary rates of spectral lines were dA series of plasma characteristic spectral lines of Mg alloy were obtained under nanosecond laser shock produced by a pulsed Nd∶YAG laser (1 064 nm, maximum energy 500 mJ), which was taken under standard atmospheric pressure and at room temperature. Results indicated that the evolutionary rates of spectral lines were different, and the laser energy was enough to ionization Mg alloy under this experimental condition by the spectral lines of MgⅠ, MgⅡ. The electron temperature of Mg plasma were calculated by the measured relative Emission-line intensity（MgⅠ383.2 nm, MgⅠ470.3 nm, MgⅠ518.4 nm）. The experimental results showed that the secondary excitation Mg atoms could be got under this experimental condition. The electron temperature of Mg plasma decreased with the laser energy reduced while the laser energy was in the range of 200～500 mJ. When the laser energy was in the range of 350～500 mJ, the electron temperature changed rapidly. When the laser energy was in the range of 200～350 mJ, the electron temperature changed slowly and tended towards stability. It is found that when the laser energy was 300 mJ, the plasma temperature raised suddenly, which could not accord with the trend because of plasma shielding. When the laser energy was 300 mJ, the relative intensity of spectral lines was reduced which was lower than that of 350 and 250 mJ. And it is against the variation trend of the relative intensity of spectral lines increases with the increase of laser energy, which prove plasma shielding phenomenon had occurred and plasma with high power laser separate the coupling between laser and material. The plasma temperature was increased significantly, which is not consistent with the trend .When the plasma shielding phenomenon happened, laser energy was absorbed by the plasma, resulting in the rise of plasma temperature..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3853 (2016)
Terahertz Spectrum Features Extraction Based on Kernel Optimization Relevance Vector Machine
ZHONG Yi-wei, SHEN Tao, MAO Cun-li, and YU Zheng-tao
Terahertz spectrum is sensitive to the change of the nonlocal molecular vibration mode. Accordingly, the spectral waveform is susceptible to variety of physical and chemical factors, which will lead to peak changes, frequency shifts, and even deformation of the overall waveform. Component analysis and material identifiTerahertz spectrum is sensitive to the change of the nonlocal molecular vibration mode. Accordingly, the spectral waveform is susceptible to variety of physical and chemical factors, which will lead to peak changes, frequency shifts, and even deformation of the overall waveform. Component analysis and material identification from the correspondence between the fixed peak features and materials will prone to cause errors or mistakes. Therefore, to solve this problem, we proposed a method based on Kernel Optimization Relevance Vector Machine (KO-RVM), which extracts global graphic features to distinct from the local features extraction method. And we use Support Vector Regression (SVR) algorithm as comparison. The result shows that, when basis functions’ parameters of RVM are optimized with expectation-maximization algorithm, it will be suitable for feature extraction of terahertz transmission spectrum. The spectrum can be sparsely represented, and the amount of extracted graphic features is substantially reduced. Reconstruction models based on these features are capable of retaining the overall spectral characteristics, and fitting results for each band are more consistent, while the extracted spectrum features can be used as basis of similarity measurement and the common characteristics investigation between different materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3857 (2016)
Research on THz and Raman Spectra of RNA Nucleobases
WANG Fang, ZHAO Dong-bo, JIANG Ling, XU Li, SUN Hai-jun, and LIU Yun-fei
The Infrared and Raman spectra of RNA nucleobases in terahertz (THz) band (1~10 THz) were detected with Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The position of all the characteristic peaks and corresponding vibration modes of RNA nucleobase crystals were obtained with Guassian09 software The Infrared and Raman spectra of RNA nucleobases in terahertz (THz) band (1~10 THz) were detected with Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The position of all the characteristic peaks and corresponding vibration modes of RNA nucleobase crystals were obtained with Guassian09 software and energy-based fragmentation approach under periodic boundary conditions (PBC-GEBF) method. The computational results were verified to be in accordance with experimental data, which indicated that the powder of RNA nucleobases is amorphous crystal structure. The infrared spectra demonstrated that adenine, guanine and cytosine all have 6 infrared active vibrational modes, while uracil only has 3. Comparing to experimental results, the position and intensity of the absorption peaks were nicely corroborated by the predicted spectrum, except that one weak vibrational frequency at 6.35 THz is missing and two peaks (4.83 and 5.39 THz) merge in the predicted spectrum of guanine; two peaks in 4.3 and 4.79 THz merge into a single one in the calculated spectrum of cytosine; the peaks of thymine in 3.32 and 3.82 THz merged. The computational results of Raman spectra were also verified to be in line with the experimental data. The position and intensity of the characteristics peaks were exactly simulated except that two peaks of guanine in 3.52 and 4.48 THz merged; two peaks in 7.26 and 8.03 THz merge and five peaks (3.57, 4.02, 4.49, 4.89, 5.98 THz) merge in the calculated spectrum of guanine. Through the analysis and identification of the characteristic peaks, it is indicated that the vibration modes of DNA nucleobases in 1~10 THz were derived from collective vibration of molecules in the lattice. The intermolecular hydrogen bond and the weak interaction force contribute greatly to the vibration modes. In addition, as the frequency increases to over 5.5 THz, the vibration modes will change from the atoms collective vibration to some atoms vibration. This research has important theoretical and practical reference value to reveal the effect of RNA nucleobases in the areas of RNA molecular structure constitution, biological macromolecules identification and terahertz spectra formation mechanism and biological inheritance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3863 (2016)
Application of Terahertz Spectroscopy in the Detection of Chinese Medicine Processed Drugs of Rhubarb
YANG Shuai, ZUO Jian, LIU Shang-jian, and ZHANG Cun-lin
The changes of composition of the processed traditional Chinese medicine will affect the curative effect of drug, such as the four kinds of processed rhubarb. The characteristics data of each rhubarb was measured with terahertz spectroscopy system and analyzed with chemometrics, and the spectral data was classified accThe changes of composition of the processed traditional Chinese medicine will affect the curative effect of drug, such as the four kinds of processed rhubarb. The characteristics data of each rhubarb was measured with terahertz spectroscopy system and analyzed with chemometrics, and the spectral data was classified according to the category of rhubarb. The substance components of anthraquinone and tannins make changes in processed rhubarb by thin layer chromatography (TLC). The correlation among the terahertz spectroscopy of processed rhubarb was in accordance with the variations of content. This means that terahertz spectroscopy is sensitive to the substance components of processed Chinese traditional medicine. It can also pave the way for the study of the structural changes of traditional Chinese medicine..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3870 (2016)
Comparison and Analysis of Iterative and Genetic Algorithms Used to Extract the Optical Parameters of Glucose Polycrystalline
LI Jia-yu, SUN Ping, ZOU Yun, LIU Wei, and WANG Wen-ai
Based on the terahertz time-domain reflection spectroscopy, the optical parameters of anhydrous D-glucose polycrystalline, i.e. the refractive index and the absorption coefficient were extracted by using iterative and genetic algorithm, respectively. After comparing and analyzing the two algorithms we had drawn the folBased on the terahertz time-domain reflection spectroscopy, the optical parameters of anhydrous D-glucose polycrystalline, i.e. the refractive index and the absorption coefficient were extracted by using iterative and genetic algorithm, respectively. After comparing and analyzing the two algorithms we had drawn the following conclusions: first, the calculation efficiency of iterative algorithm was improved using the solution of weak absorption approximation as initial values. However, the iterative algorithm was sensitive to the initial values. When the big difference between the initial values and real values existed, the accuracy of optical constants would be affected; Secondly, the genetic algorithm was not insensitive to the initial populations. It ensured the convergence of the algorithm and the population diversity through the design of parameter coding, initial population, genetic manipulation, parameter control and constraint condition. Last, compared with the iterative algorithm, the optical parameters obtained by the genetic algorithm had higher accuracy. Therefore, we suggest that the optical parameters of materials with higher accuracy based on the THz spectroscopy can be obtained by using an intelligent optimization algorithm..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3875 (2016)
Model Optimization of Ternary System Adulteration Detection in Camellia Oil Based on Visible/Near Infrared Spectroscopy
MO Xin-xin, ZHOU Ying, SUN Tong, WU Yi-qing, and LIU Mu-hua
Visible/near infrared spectroscopy combined with chemometrics methods was used to detect ternary system adulteration in camellia oil quantificationally. In order to get adulterated samples, rapeseed oil and peanut oil were added to pure camellia oil in different proportion. Visible/near infrared spectroscopy data of puVisible/near infrared spectroscopy combined with chemometrics methods was used to detect ternary system adulteration in camellia oil quantificationally. In order to get adulterated samples, rapeseed oil and peanut oil were added to pure camellia oil in different proportion. Visible/near infrared spectroscopy data of pure and adulterated camellia oil samples were acquired in the wavelength range of 350~1800nm, and samples were randomly divided into calibration set and prediction set. The adulteration models were optimized by comparing different wavelength ranges, pretreatment methods and calibration methods The results show that the optimal modeling wavelength ranges and pretreatment methods for the prediction models of rapeseed oil, peanut oil and total adulteration amount are 750~1 770, 900~1 770, 870~1 770 nm and Multiple scattering correction (MSC), Standard normal variate (SNV) and second order differentia, and the best modeling method is Least square support vector machine (LSSVM). The correlation coefficient (RP) in prediction set and the root mean square error predictions(RMSEPs) of optimal adulteration models for rapeseed oil, peanut oil and total adulteration are 0.963, 0.982, 0.993 and 2.1%, 1.5%, 1.8%, respectively. Thus it can be seen that visible /near infrared spectroscopy combined with chemometrics methods can be used for quantitative ternary system adulteration detection in camellia oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3881 (2016)
Research on Cloud Phase Detemination Using Infrared Emissivity Spectrum Data (1): Cloud Phase Determination
LIU Lei, SUN Xue-jin, and GAO Tai-chang
As a key factor in the climate model, cloud phase is an important prerequisite to performing cloud property retrievals from remote sensor measurements. The ability to infer cloud phase using cloud emissivity spectra is investigated by numerical simulations. It is shown that for emissivity below 0.95, several spectral fAs a key factor in the climate model, cloud phase is an important prerequisite to performing cloud property retrievals from remote sensor measurements. The ability to infer cloud phase using cloud emissivity spectra is investigated by numerical simulations. It is shown that for emissivity below 0.95, several spectral features such as the slopes, the ratios and the differences of the emissivity are consistent with the variation of cloud phase in some spectral regions. Specifically, these features include the slope of the cloud emissivity between 800 and 900 cm-1, the slope of the cloud emissivity between 900 and 1 000 cm-1, the difference in the mean emissivity between above-mentioned two regions, the ratio of the emissivity at 862.1 cm-1 to the emissivity at 989.8 cm-1, the difference in the emissivity between 862.1 and 989.8 cm-1, the ratio of the emissivity at 1 900.1 cm-1 to the emissivity at 2 029.3 cm-1, the ratio of the mean emissivity for far-infrared region to the emissivity at 900 cm-1. A cloud phase classifier is proposed based on support vector machines (SVM). A series of simulations including various cloud patterns are performed. The RBF kernel function parameters and the penalty factor of SVM are selected by using the genetic algorithm. The phase determination algorithm is applied for collecting data from the AERI at the SGP site. The results from the ground-based multisensor cloud phase classifier proposed by Shupe are used to validate the phase determination algorithm. It is found the two results are consistent in general. 30% clouds are indicated as opaque due to its high emissivity. The cloud with small lidar’s depolarization is misclassified as clear sky by the Shupe method. It can be concluded that the proposed algorithm considering the spectral information (spectral slopes, ratios and differences) is efficient for cloud phase determination of thin cloud..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3885 (2016)
Research on Cloud Phase Detemination Using Infrared Emissivity Spectrum Data (2): Retrieval of Cloud Effective Radius and Water Path
LIU Lei, SUN Xue-jin, and GAO Tai-chang
The cloud microphysical properties such as cloud effective radius and cloud water path are fundamental properties for understanding the cloud formation, radiative impacts and interactions with aerosol and precipitation. The downwelling infrared radiance spectra is studied here to retrieve microphysical properties of clThe cloud microphysical properties such as cloud effective radius and cloud water path are fundamental properties for understanding the cloud formation, radiative impacts and interactions with aerosol and precipitation. The downwelling infrared radiance spectra is studied here to retrieve microphysical properties of clouds. The sensitivity of the downwelling radiance spectra and cloud emissivity spectra to the liquid cloud and ice cloud effective radius and optical depth is analyzed. The look-up-tables are established for optically thin clouds (cloud optical depth less than 6) that rely on parameters of the slopes and differences of the emissivity spectra. These parameters include the difference in the emissivity between 862.1 and 934.9 cm-1, the difference in the emissivity between 1 900.1 and 2 170.1 cm-1, the slope of the cloud emissivity and the radiation between 900 and 1 000 cm-1, the slope of the cloud emissivity and the radiation between 1 100 and 1 200 cm-1. The look-up-tables are constrained by the incorporation of mean ozone band transmissivity between 1 050 and 1 060 cm-1. Cloud effective radius and optical depth can be obtained with by least squares fitting between observed and modeled above-mentioned multiple spectral parameters. The cloud water path can then be derived from the experiential relationship. The inversion results are compared with the ARM baseline cloud microphysics product (MICROBASE). It is shown that, the cloud effective radius is roughly in the same order of magnitude while the water paths derived from both method are of large differences especially for the liquid cloud path. The algorithm proposed in this paper is efficient for retrieving microphysical properties of thin clouds with cloud optical depth less than 6..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3895 (2016)
Visible and Infrared Thermal Image Fusion Algorithm Based on Self-Adaptive Reference Image
LIU Jia-ni, JIN Wei-qi, LI Li, and WANG Xia
The technology of fusing visible images and infrared thermal images is one of the most important researching fields in terms of high-performance night vision technology home and abroad Using this kind of technology can efficiently improve people’s ability of target-detecting and scene’s comprehension. The commonly usedThe technology of fusing visible images and infrared thermal images is one of the most important researching fields in terms of high-performance night vision technology home and abroad Using this kind of technology can efficiently improve people’s ability of target-detecting and scene’s comprehension. The commonly used color transfer algorithm belongs to single reference image’s global color transfer, which results in huge influence on the color of fusion image. Thus, this kind of method cannot adapt to different kinds of scenes. In this essay, we focus on environmental adaptation problems of regular color transfer in color image fusion algorithm base on YUV color space. After analyzing the mean and standard deviation of typical scenes’ UV channel, we find that it has obvious classified characteristics. As a result, we propose a method of constructing adaptive reference image based on mean and standard deviation of U and V channels, which makes visible and infrared thermal image fusion algorithm better adapt to environment and fusion images’ color is natural. Furthermore, the handling capacity is small and it exerts little impact on the speed of algorithm real-time hardware processing. To conclude, it is a kind of practical natural color fusion processing algorithm..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3907 (2016)
Qualitative Detection of Procymidone in Edible Vegetable Oils by Near Infrared Spectroscopy and Variable Selection Methods
SUN Tong, MO Xin-xin, LI Xiao-zhen, WU Yi-qing, and LIU Mu-hua
In this research, near infrared (NIR) spectroscopy was used to detect procymidone in edible vegetable oils qualitatively. Edible vegetable oil samples with different procymidone contents were classified to two groups according to boundary line of maximum residue limit of procymidone in national standard. QualitySpec spIn this research, near infrared (NIR) spectroscopy was used to detect procymidone in edible vegetable oils qualitatively. Edible vegetable oil samples with different procymidone contents were classified to two groups according to boundary line of maximum residue limit of procymidone in national standard. QualitySpec spectrometer was used to acquire spectra of two group samples, then uninformative variable elimination (UVE) and subwindow permutation analysis (SPA) were used to select informative wavelength variables. At last, several methods such as linear discriminant analysis (LDA), partial least squares-linear discriminant analysis (PLS-LDA) and discriminant partial least squares (DPLS) were used to develop classification models. The results indicate that NIR spectroscopy is feasible to classify the two group samples. UVE method can select informative wavelength variables effectively, and improve the performance of classification model. The best model is developed by UVE-DPLS method, the classification correct rate, sensitivity and specificity of prediction samples in this model are 98.7%, 95.0% and 100.0%, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3915 (2016)
Study of Modeling Samples Selection Method Based on Near Infrared Spectrum
JIN Zhao-xi, ZHANG Xiu-juan, LUO Fu-yi, AN Dong, ZHAO Sheng-yi, RAN Hang, and YAN Yan-lu
For more wheat varieties classification problem, we use near infrared spectrumto do qualitative analysis. Increasing the size of modeling sample could increase information of the model, however, at the same time, it also makes information redundancy so that modeling time and storage space will increase, thus, we need tFor more wheat varieties classification problem, we use near infrared spectrumto do qualitative analysis. Increasing the size of modeling sample could increase information of the model, however, at the same time, it also makes information redundancy so that modeling time and storage space will increase, thus, we need to decrease the size of modeling sample though selecting them. Some information must be lost and the effects of the model must be worse if we select samples blindly. We put forward the k nearest neighbor-density sample selection based on the traditional selection methods. Experiments use the near infrared diffuse reflection spectrum of wheat seed from lots of days. First, we use preprocessing and feature extraction to deal with the wheat original spectrum, then select modeling sample by three methods that are random sampling, k nearest neighbor and k nearest neighbor-density, finally, we establish the models of BPR(Biomimetic Pattern Recognition) and BPRI(Biomimetic Pattern Recognition Improved). The experimental results show that in the model of BPR we get the best results using the selection method of k nearest neighbor-density, especially it also decreases the size of modeling sample deeply, and in the model of BPRI the results using the selection method of k nearest neighbor-density are much better than random sampling and a little better than k nearest neighbor, but in the meanwhile the size of modeling sample using the selection method of k nearest neighbor-density are much smaller than k nearest neighbor. The experimental results prove that the sample selection method of k nearest neighbor-density can not only greatly reduce the modeling sample size, and ensure the quality of the model, it has obvious effect on varieties classification problem of wheat..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3920 (2016)
Characterizing Fracture Characteristics of Heterogeneous Oil and Gas Reservoir by Using Microscopic Infrared Spectroscopy Technique——Taking Carbonate Reservoir of the Wumishan Formation of Jixian System in Renqiu Burried Hill as an Example
ZHOU Han-guo, GUO Jian-chun, LI Jing, LIU Si-meng, PENG Cheng-le, and HOU Jiang-peng
Oil and gas reservoir fracture is not only the important reservoir space, but also the main passage of the oil and gas migration. Therefore, the characterization of fracture is of great importance. However, reservoir rocks have strong heterogeneity, how to characterize heterogeneous reservoir fracture accurately is an Oil and gas reservoir fracture is not only the important reservoir space, but also the main passage of the oil and gas migration. Therefore, the characterization of fracture is of great importance. However, reservoir rocks have strong heterogeneity, how to characterize heterogeneous reservoir fracture accurately is an urgent problem to be solved. Microscopic infrared spectroscopy imaging technique can be used to analyze spectral curve of the mineral molecules, different peak characteristics were got, and rock medium composition, the size of the rock fracture, and fracture filler properties and other characteristics were obtained accurately. In this work, carbonate heterogeneous reservoir of Renqiu buried hill was taken as an example, based on the microscopic infrared spectroscopy imaging technique, by the analysis of core sample infrared imaging spectrogram and spectral curves of different characteristic regions, the physicochemical characteristics of the target sample and spatial distribution of the rock medium were obtained, the regions where rock fracture maybe occurred were predicted and the effectiveness of the fractures was analyzed. The results show that the main medium of rock sample is dolomite. The rock fractures contain hydrocarbon organic and salt-water inclusion, which mainly exist in dolomite medium. The proportion of salt-water inclusion is 51.7%, and that of alkane organic matter is 26.0% in the fracture filler. The fracutres extend from the upper left region of core sample to the lower right region, which shows that the extended region of the core sample may be the passage of fluid migration. The salt-water inclusions can impede the migration of oil and gas, resulting in the decrease of fractures permeability. The experimental results show that the width of fractures is 1～1.5 mm, which belongs to large fracture, oil and gas can pass the fractures smoothly, therefore, the effectiveness of the fracture is good. The results showed that it is feasible to characterize the fracture of heterogeneous reservoir by means of microscopic infrared spectroscopy imaging technique, and it provides a new method for the accurate characterization of the fracture of heterogeneous reservoir..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3926 (2016)
Wavelength Variable Selection Method in Near Infrared Spectroscopy Based on Discrete Firefly Algorithm
LIU Ze-meng, ZHANG Rui, ZHANG Guang-ming, and CHEN Ke-quan
Taking into consideration of the large size of near-infrared spectral data, the spectral data has to be compressed to reduce the computational complexity of the established spectral calibration model and improve accuracy and robustness of the model. Near Infrared Spectroscopy wavelength variable selection method based Taking into consideration of the large size of near-infrared spectral data, the spectral data has to be compressed to reduce the computational complexity of the established spectral calibration model and improve accuracy and robustness of the model. Near Infrared Spectroscopy wavelength variable selection method based on discrete firefly algorithm is presented. First, the Monte Carlo method was used to exclude outliers, and Kennard-Stone method was chosen for the selection of calibration set and prediction set. General firefly algorithm was discretized, by improving the attractiveness of adaptive formula, increasing traction weights in mobile formula and so on. In order to adapt to the effects of discretization and optimize algorithm, elitist strategy was added in the discrete firefly algorithm, to acceleratethe convergence rate. The optimum value of the DFA algorithm parameters was found in the experiment. With wavelength variables selection based on discrete firefly algorithm, succinic acid concentration of the fermentation broth partial least squares NIR calibration model was built, which was compared with genetic algorithm method. The results showed that the correlation coefficient of calibration set (R2c) of PLS calibration model based on discrete wavelengths firefly algorithm is 0.986, RMSEC of which is 0.409. Correlation coefficient of prediction set (R2p) is 0.969 while RMSEP is 0.458. It is superior to full spectrum modeling and calibration model using genetic algorithm method. DFA shows superiority of the near-infrared spectral data filtering..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3931 (2016)
Quantitive Analysis of Contents in Yogurt and Application Research with FTIR Spectroscopy
ZHAO Yan, WANG An-lin, CHENG Nian-shou, LI Zhong-yan, ZHU Chang-wei, and CAI Chuan-jie
Yogurt is a food produced by bacterial fermentation of milk. All kinds of nutrition components are changing dramatically in the process of fermentation. Therefore, it is important to establish a fast and efficient measurement technology of yogurt nutrition, which is also an important goal for food safety supervision inYogurt is a food produced by bacterial fermentation of milk. All kinds of nutrition components are changing dramatically in the process of fermentation. Therefore, it is important to establish a fast and efficient measurement technology of yogurt nutrition, which is also an important goal for food safety supervision in terms of monitoring the yogurt production process in real time. Fourier transform infrared spectroscopy (FTIR) has been widely used in the field of food safety, for it has high efficiency, high throughput, no chemical pollution, thus it can be used in the inspection of food adulteration. Our study has established a quantitative model to predict the nutrition components in yogurt, such as energy value, protein, fat, carbohydrates and sodium content. Based on the least squares (PLS) method, the model used CaF2 film FTIR technology. The results show that the new model can be used in quality control of yogurt production process: The R2 values of the model were 0.938 9, 0.926 6, 0.918 6, 0.941 8 and 0.977 1, comparing energetic value, protein, fat, carbohydrate and sodium contents with the original spectrum of calibration samples by cross validation. And the predictive R2 are 0.920 5, 0.905 3, 0.908 5, 0.939 3 and 0.936 4 respectively. Thus, the model has good prediction accuracy and reliability, which provides a feasible method for the rapid measurement of yogurt quality. As a preliminary exploration of the quality control technology of dairy products, this method has a good prospect of application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3937 (2016)
Quantitative Analysis for Levocetirizine Hydrochloride Tablets Based on NIR Spectroscopy
WANG Qin, LIU Ye-hai, GAO Min-guang, and ZHAO Min-jie
The aim of this study was to develop a quantitative analytical method to measure the effective components in the left cetirizine hydrochloride tablets using near infrared spectroscopy combining with a partial least square (PLS) analysis model. The method was internal cross-validated to determine the best wavelength ranThe aim of this study was to develop a quantitative analytical method to measure the effective components in the left cetirizine hydrochloride tablets using near infrared spectroscopy combining with a partial least square (PLS) analysis model. The method was internal cross-validated to determine the best wavelength range, spectral preprocessing methods and the optimal number of principal components. The concentration of validation set samples was predictable by PLS model. The RMSECV value was 0.276, and the R2 value was 0.974. Our study suggests that this model can be used for rapid quantitative analysis of left cetirizine hydrochloride tablets from different manufacturers..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3941 (2016)
Rapid Determination of Pinoresinol Diglucoside and Geniposidic Acid in Eucommia ulmoides with Near Infrared Spectroscopy Combined with
LI Fang-fei, PENG Ying-zhi, XU Xiong-bo, ZI Wen, LIU Rui, and LIU Shao
To develop a quantitative models for simultaneous determination of pinoresinol diglucoside (PDG) and geniposidic acid (GPA) in Eucommia ulmoides with near-infrared (NIR) spectroscopy combined with chemometrics. The NIR spectra were collected in diffuse reflection mode and pretreated with various spectra preprocessing mTo develop a quantitative models for simultaneous determination of pinoresinol diglucoside (PDG) and geniposidic acid (GPA) in Eucommia ulmoides with near-infrared (NIR) spectroscopy combined with chemometrics. The NIR spectra were collected in diffuse reflection mode and pretreated with various spectra preprocessing methods including first-order differentiator, multiplicative scatter correction and so on. The optimal wavelength variables were screened out by competition adaptive weighted sampling method. The quantitative models for the simultaneous determination of PDG and GPA in Eucommia ulmoides were established with partial least squares (PLS) algorithm and cross validation methods. The quantitative prediction models for simultaneous determination of PDG and GPA in Eucommia ulmoides showed good predictive ability. The correlation coefficients (R2) of the two calibration models were 0.961 5, 0.958 3 while the roots mean square of cross-validation (RMSECV) were 0.001 5, 0.006 4, respectively. The quantitative prediction models proved that near infrared spectra method used for the quantitative analysis of PDG and GPA in Eucommia ulmoides owned high prediction accuracy and can meet the precision need of rapid determinations of PDG and GPA in Eucommia ulmoides in reality so t it provides a new method to realize the real time on line of quality control of Eucommia ulmoides..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3945 (2016)
The Research of Spatial Heterodyne Raman Spectroscopy with Standoff Detection
HU Guang-xiao, XIONG Wei, LUO Hai-yan, SHI Hai-liang, LI Zhi-wei, SHEN Jing, and FANG Xue-jing
Spatial heterodyne Raman spectroscopy (SHRS) is a new type of Raman spectroscopic detection technique with characteristics of high optical throughout, high spectral resolution, and no moving parts. SHRS is very suitable for the planetary exploration missions, which can be used to the analysis of minerals and find the bSpatial heterodyne Raman spectroscopy (SHRS) is a new type of Raman spectroscopic detection technique with characteristics of high optical throughout, high spectral resolution, and no moving parts. SHRS is very suitable for the planetary exploration missions, which can be used to the analysis of minerals and find the biomarkers maybe exist on the surface of planetary. The authors have applied the technique to the standoff Raman spectroscopic detection, analyzed the main characteristics, including spectral resolution, bandpass and signal to noise (SNR), of standoff SHRS and proved it through experiments. The basic theory of standoff SHRS has been described briefly while a breadboard has been designed, built and calibrated. On the basis, the Raman spectra of some inorganic solids, organic liquids and some natural minerals have been achieved at a distance of 10 m, the SNR of the breadboard has been estimated. Due to the poor adjustment and the defects of the optical elements, the breadboard is far away from an ideal system. But the results show that the SNR is better than 5 for most of the main Raman peaks of the samples, which can meet the basic requirement of clear positive detection of typical Raman peaks and the feasibility of standoff SHRS has been proved. SHRS can overcome the main defects of dispersive grating Raman spectrometers and Fourier transform Raman spectrometers and it has a great application prospect on the detection and analysis of the planetary surface. The work of the authors can prove the potentiality of SHRS on standoff detection and can provide reference for the engineering realization of standoff SHRS..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3951 (2016)
Confocal Raman Spectroscopy Method Based on Quadratic Curve Fitting
CUI Han, WANG Yun, QIU Li-rong, ZHAO Wei-qian, and ZHU Ke
Raman spectroscopy plays an improtant role in analytical science because of its unique characteristics, such as non-contact and non-destructive detecting, fewer sample consumption, high sensitivity and other characteristics, and it provides a powerful analytical tool for the modern basic research fields. Because of theRaman spectroscopy plays an improtant role in analytical science because of its unique characteristics, such as non-contact and non-destructive detecting, fewer sample consumption, high sensitivity and other characteristics, and it provides a powerful analytical tool for the modern basic research fields. Because of the combination of confocal microscopy technology and Raman spectroscopy technology, confocal Raman microscopy has the advantage of both high resolution spectroscopy and chromatography detection, which inherits from confocal microscopy and raman spectroscopy. As a result, it is widely used in many fields, such as physical chemistry, materials science, biomedical, archaeological, cultural identification, and forensic science. But with the environmental changing, the system drifting or other issues, during the long detection process, the system turns to defocusing. As a result, during the hole scanning process, the system can not be focused on every detection point, and then it would lead to a mistake. Eventurally, conventional confocal Raman system could obtain the presence of measurement error even erroneous results in the long process. In this paper, on the basis of conventional confocal Raman system, a confocal Raman spectroscopy method based on quadratic curve fitting is proposed to solve this problem. Based on the principle that the maxium of the concal curve corresponding the system foucs, the steps to find system foucus as follows: fist, usesing quadratic curve to fit confocal curve; second, finding the maxium of the confocal curve; and last obtaining the system foucs. With this method, during the scanning process, every point should be focused, therefore, the effect of defocusing is eliminated efficiently, and accurate measurements of confocal Raman spectroscopy system is achieved.Through simulation and experimental results show that: the proposed method that confocal Raman spectroscopy method based on quadratic curve fitting can effectively eliminate the influence of system defocus on experimental result, and effectively improve the axial system of fixed focus accuracy, which could provide a guarantee for further application of confocal Raman spectroscopy. This anti-drift method is effective and accurate in focusing with great potential to be applied in broader areas..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3958 (2016)
Surfaced-Enhanced Raman Scattering Spectroscopic Study on Sheng-Di-Dang-Gui Decoction
CHEN Wei-wei, LIN Jia, CHEN Rong, FENG Shang-yuan, YU Yun, LIN Duo, SHI Hong, and HUANG Hao
To reveal the relationship between the single decoction and prescription, the surface-enhanced Raman scattering (SERS) spectroscopy of Sheng-Di-Dang-Gui decoction (SDDGD), Sheng-Di decoction (SDD) and Dang-Gui decoction (DGD) were tested and analyzed. Mainly seventeen Raman signals (538, 622, 732, 761, 835, 876, 959, 1To reveal the relationship between the single decoction and prescription, the surface-enhanced Raman scattering (SERS) spectroscopy of Sheng-Di-Dang-Gui decoction (SDDGD), Sheng-Di decoction (SDD) and Dang-Gui decoction (DGD) were tested and analyzed. Mainly seventeen Raman signals (538, 622, 732, 761, 835, 876, 959, 1 145, 1 245, 1 276, 1 326, 1 402, 1 456, 1 470, 1 518, 1 546 and 1 605 cm-1) in three decoctions were discussed. The characteristic Raman bands of three decoctions were tentatively assigned. Fifteen obvious Raman bands (538, 732, 761, 835, 876, 959, 1 145, 1 245, 1 276, 1 326, 1 402, 1 456, 1 470, 1 518 and 1 605 cm-1) were observed in the SERS spectroscopy of SDDGD, thirteen obvious Raman bands (538, 761, 835, 876, 959, 1 145, 1 245, 1 276, 1 326, 1 402, 1 470, 1 518 and 1 546 cm-1) were observed in the SERS spectroscopy of SDD, ten obvious Raman bands (538, 622, 732, 761, 835, 876, 959, 1 245, 1 326 and 1 402 cm-1) were observed in the SERS spectroscopy of DGD. Some Raman bands in SERS spectra of SDD and DGD were retained in the SDDGD, however some Raman bands in two kinds of decoctions never appeared in the SDDGD. And new Raman bands (1 456 and 1 605 cm-1) were generated in the SDDGD, resulted in the fact that new chemical compositions were created. Medical ingredients in the SDDGD were not the simple addition of SDD and DGD. The results showed that the SERS spectroscopy might provide a new kind of novel, effective and simple detecting method for the prescription research..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3963 (2016)
Study on Line CARS for Temperature Measurement in Combustion Flow Field
LI Ren-bing, SU Tie, ZHANG Long, BAO Wei-yi, YAN Bo, CHEN Li, and CHEN Shuang
Some laser beams meet at a single point by a convex len in normal coherent anti-Stokes Raman scattering (CARS), and the CARS signal with temperature information of the focal piont yields under phase matching. Normal CARS can only get the temperature of one spatial piont in one measurement, which can not meet the needs Some laser beams meet at a single point by a convex len in normal coherent anti-Stokes Raman scattering (CARS), and the CARS signal with temperature information of the focal piont yields under phase matching. Normal CARS can only get the temperature of one spatial piont in one measurement, which can not meet the needs of deep research on combustion flow field. In order to get more information in one test and improve the measuring capacity of CARS, line CARS (L-CARS) was presented. In L-CARS, convex lens are replaced by cylindrical convex lens to get a focal line, and nearly all the points on the line meet the phase matching. So, the CARS signal of each point on the line yield in one test. Cylindrical convex lens are also used in subsequent beam path to focus the CARS signals into spectrometer, and ICCD camera transfers the signals to computer to acquire the temperature of each point. Then, the measuring capacity of CARS is advanced from piont measuring to line measuring. Experimental results based on plain flame furnace suggest that L-CARS can acquire about 200 points’ temperatures effectively in one test, and the length of the measuring line is about 3.6mm. The spatial resolution is about 18μm and the uncertainty is less than 7%, which is as the same as the ordinary CARS’s..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3968 (2016)
Precise and Rapid Detection of Glutathione by Using Novel Fluorescent Ag Nanoclusters
HUANG Ke-han, QIN Cui-fang, CAO Xiao-dan, YANG Tai-qun, CHEN Yu-ting, ZHANG San-jun, PAN Hai-feng, and XU Jian-hua
Glutathione (GSH) is an important three-peptide molecule, which has the functions of antioxidation and detoxification, and plays a crucial role in the fields of biology, medicine and food science. It is involved in many important biochemical reactions in cells and body fluid, and the changes of GSH content reflect the Glutathione (GSH) is an important three-peptide molecule, which has the functions of antioxidation and detoxification, and plays a crucial role in the fields of biology, medicine and food science. It is involved in many important biochemical reactions in cells and body fluid, and the changes of GSH content reflect the specific health problems of human body. Current methods of GSH detection are always complicated, time-consuming and expensive instrument depended, such as surface enhanced Raman spectroscopy (SERS), electrochemical analysis, high performance liquid chromatography (HPLC) and so on. The probe’s photochemical properties can be modified by the reaction between GSH and nanoclusters, which will result in the changes of fluorescence intensity and wavelength. In this paper, a new method to realize precise and rapid GSH detection is developed by using silver na-noclusters as a fluorescent probe, and simultaneously measures the probe’s fluorescence intensity and wavelength. The synthesis of the fluorescence probe reported in this paper possesses the advantages of steps-simple and pollution free, and the GSH detection method has faster response, more accurate measurement and smaller relative error over the traditional methods. The good specificity of GSH detection among other molecules with the similar structure is further proved in control group experiments by comparing the differences of their fluorescence intensities and wavelength. The measurement accuracy is fully assured due to the insensitivity of the probe to a variety of salt ions and amino acids. This technique can be further employed in the intracellular detection and imaging of GSH..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3973 (2016)
Soft Measurement of the Purity of the Synthetic Edible Pigment Powder Using Fluorescence Spectroscopy Combined with SVM
ZHANG Yi, CHEN Guo-qing, ZHU Chun, ZHU Zhuo-wei, and XU Rui-yu
The feature compression algorithm which was reformed from the original Moment method was used for the pre-processing of the fluorescence spectral data, then combined the data and the Weighted Least Squares Support Vector Machine(WLS-SVM) algorithm to establish a robust regression model, which is used for forecasting thThe feature compression algorithm which was reformed from the original Moment method was used for the pre-processing of the fluorescence spectral data, then combined the data and the Weighted Least Squares Support Vector Machine(WLS-SVM) algorithm to establish a robust regression model, which is used for forecasting the purity of edible pigment powder. In this paper, brilliant blue and ponceau 4R served as an example to discuss the method of forecasting effect of edible pigment powder purity. The emission fluorescence spectra of two edible pigment at the optimal excitation wavelength were measured by FLS920 fluorescence spectrometer. The compression and transformation of the fluorescence spectral data was acquired by the feature compression algorithm reformed from the Original Moment method. On the one hand the feature compression algorithm shortened the operation time, on the other hand it improved the prediction accuracy of the model. Then, the concentration prediction model was established after inputting the fluorescence spectral data pre-processed into the Weighted Least Squares Support Vector Machine. The model gave anastomotic predicted spectral data with the actual experiments of the brilliant blue and ponceau 4R, and the average coefficient of determination in the half peak width was 0.700 and 0.930 respectively. There was a good linear relationship between the predicted and the nominal concentration of the brilliant blue and ponceau 4R, and the correlation coefficients were 0.997 and 0.992 respectively. It can be concluded that, the predicted concentration of the brilliant blue and ponceau 4R powder were got the results of 61.0% and 72.3% respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3978 (2016)
Calculation of Chlorophyll Fluorescence Characters in Different Light Area to Apple Tree Canopy
MA Xiao-dan, GUO Cai-ling, ZHANG Xue, LIU Gang, LIU Guo-jie, and ZONG Ze
As the basis of plant canopy chlorophyll fluorescence kinetics, light distribution within the canopy determines the interaction relationship between plant physical processes and ecological environment. Spectroscopy technology plays a very important role in building a prediction model of component content to plant canopAs the basis of plant canopy chlorophyll fluorescence kinetics, light distribution within the canopy determines the interaction relationship between plant physical processes and ecological environment. Spectroscopy technology plays a very important role in building a prediction model of component content to plant canopies. However, there is only limited number of reports about chlorophyll fluorescence properties of different light intensity areas to free spindle apple canopies. In this paper, with the free spindle apple tree as the research object, the canopy space of apple tree was divided into five layers, and six cube grids with 50cm length of side in each layer, and then the light distribution was determined through measuring the light intensity of each cube grids space. firstly, spectrum data and characters of chlorophyll fluorescence were obtained in the different light area; secondly, a differential spectrum curve in red area(680~760 nm) was determined through removing the interference of system error by a differential spectrum; thirdly, relationship model has been established innovatively between the maximum value in red area(680~760 nm) and the chlorophyll fluorescence characters, which has been used as calculation method of chlorophyll fluorescence characters in different light area to apple tree canopy. Fourthly, root mean square error, mean absolute percentage error, mean forecast error were adopted to evaluate the method. The test result shows that the accuracy of the method is all above 80%, which can be the theoretical basis for pruning and getting best light distribution to apple tree canopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3986 (2016)
Fluorescence Spectroscopic Studies on Binding of 20(S)-Protopanaxatriol with Bovine Serum Albumin
ZHANG Zhao-hua, CHI Shao-ming, PAN Zhen-jie, LI Zhi-wen, LI Ya-juan, HU Tian-feng, CHEN Yan-mei, and ZHAO Yan
The interaction between 20(S)-protopanaxatriol (PPT) and bovine serum albumin ( BSA) was studied with fluorescence quenching technique and ultra-violet absorption spectroscopy. The results indicated that PPT led to the intrinsic fluorescence quenching of BSA through a static quenching process .The binding constants of The interaction between 20(S)-protopanaxatriol (PPT) and bovine serum albumin ( BSA) was studied with fluorescence quenching technique and ultra-violet absorption spectroscopy. The results indicated that PPT led to the intrinsic fluorescence quenching of BSA through a static quenching process .The binding constants of PPT with BSA obtained with fluorescence quenching method were calculated as 0.926 3×103 (298 K), 0.618 2×103 (308 K), 0.414 4×103 L·mol-1(318 K), respectively; while the number binding sites n were close to unity. The results showed that the driving force of the interaction between PPT and BSA was hydrogen bond and Van der Waals force. The result of synchronous fluorescence spectra showed that binding of PPT with BSA could induce conformational changes in BSA, that the part of tryptophan became more closely. According to Fster fluorescence resonance energy transfer theory, the binding distance r and energy-transfer efficiency E were respectively 26.2 nm and 0.32..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3991 (2016)
Study on Recognition Model of Phyllosilicate of Martian Surface
ZHANG Xia, WU Xing, YANG Hang, CHEN Sheng-bo, and LIN Hong-lei
Phyllosilicate belongs to hydrated silica, which is a principal form of hydrous minerals on the martian surface. It’s also an indicator in comparing different sediments and degree of aqueous alteration. Therefore, it’s essential to establish its recognition model for studying the geologic evolution of the Mars. Short-wPhyllosilicate belongs to hydrated silica, which is a principal form of hydrous minerals on the martian surface. It’s also an indicator in comparing different sediments and degree of aqueous alteration. Therefore, it’s essential to establish its recognition model for studying the geologic evolution of the Mars. Short-wave infrared (SWIR) spectral bands and thermal infrared (TIR) spectral bands have distinct spectral response to the mineral groups and ions, so they have distinctive advantages in detecting minerals. However the method of combining SWIR and TIR to recognize phyllosilicate is rarely studied. Based on the USGS spectral library, facing Compact Reconnaissance Imaging Spectrometer for Mars(CRISM) and Thermal Emission Imaging System(THEMIS),we conducted the research on the mechanism of the spectral response of phyllosilicate, and established the SWIR and TIR identification model respectively, then combined the SWIR and TIR spectral features to build the combined recognition model of phyllosilicate with Fisher discriminant analysis. The results of cross validation show that the identification accuracy of combined model is the highest, which can correctly classify 90.6% of the mineral samples and improve the identification precision of phyllosilicate effectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 3996 (2016)
Simultaneous Detection of Multiple Quality Parameters of Pork Based on Fused Dual Band Spectral
WANG Wen-xiu, PENG Yan-kun, XU Tian-feng, and LIU Yuan-yuan
For dual band visible/near infrared spectroscopy system (350~1 100 and 1 000~2 500 nm), there exsits a band overlap and for the same sample the reflectivity data were unlike due to the performance difference between instruments. A band connection and data fusion method was proposed in this paper to make better use of tFor dual band visible/near infrared spectroscopy system (350~1 100 and 1 000~2 500 nm), there exsits a band overlap and for the same sample the reflectivity data were unlike due to the performance difference between instruments. A band connection and data fusion method was proposed in this paper to make better use of the dual-band data. A dual-band visible/near-infrared spectroscopy system was built in the study to collect 60 pork samples’ reflectance spectra. The reflectance spectra of samples were performed with pretreatment methods of Savitzky-Golay (S-G) and standard normal variable transform to eliminate the spectral noise. Then partial least squares regression (PLSR) prediction models of pork quality attributes (color, pH and cooking loss) based on single-band spectrum and dual-band spectrum were established, respectively. For the cross of two band overlap, the data were connected and integrated using the method put forward in this paper and then PLSR models were established based on the integrated data. The PLSR model yielded prediction result with correlation coefficient of validation (Rp) of 0.948 8, 0.920 0, 0.950 5, 0.930 1 and 0.903 5 for L*, a*, b*, pH value and cooking loss, respectively. To simplify the model, uninformative variables elimination (UVE) was employed to select characteristic variables. The experimental results show that the proposed method was able to achieve a better fusion of the two band spectral data, and it was good for the establishment of a more simplified and better prediction model..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4001 (2016)
Measuring the Spectrum of Extinction Coefficient and Reflectance for Cadmium Compounds from 400 to 900 nm
LIANG Ye-heng, DENG Ru-ru, LIU Yong-ming, LIN Li, QIN Yan, and HE Ying-qing
The key to extract the contents of cadmium in water by using remote sensing technique is to measure the spectrum of extinction coefficient per g·L-1 and reflectance for its compounds. So in this paper, firstly, we choose two kinds of cadmium compounds, cadmium sulfide (CdS) and cadmium oxide (CdO), which are most The key to extract the contents of cadmium in water by using remote sensing technique is to measure the spectrum of extinction coefficient per g·L-1 and reflectance for its compounds. So in this paper, firstly, we choose two kinds of cadmium compounds, cadmium sulfide (CdS) and cadmium oxide (CdO), which are most commonly exsit in natural water, to measure the spectrums of extinction coefficient and reflectance for them. We use the equipment, designed on our own, which can adjust the path length of light passing and make our measuring results more accurate at visible and near-infrared wavelength range than others. Then we use Analytical Spectral Devices (ASD) spectrometer to measure the radiance of the light spot, which is from the direct light passed through cadmium compounds solutions of different concentrations reflected by the standard board. Using the ratio method to eliminate environmental errors and the effects of the thimbleful of suspended solids in water, we obtain the extinction coefficient per g·L-1 of these two kinds of cadmium compounds from 400 to 900 nm. Secondly, we use ASD spectrometer to measure the reflectance spectrum of them in the sunny day at outdoor. The reflectance we obtain in this paper can help us to calculate the absorption and scattering coefficient per g·L-1 in the future. The measuring results show that the extinction coefficient spectrum of CdS has two troughs at 550 and 830 nm and one peak at 675 nm. And the extinction coefficient spectrum of CdO decrease from purple to near-infrared. Both of their coefficient spectrums in blue are larger than green and red. And the value of the extinction coefficient per g·L-1 of CdS is larger than CdO in the whole measuring wavelength range. The reflectance of CdS in yellow and red is larger than purple and blue, which increases rapidly from 500 to 650 nm and then leveling off. While the reflectance of CdO increase linearly from 525 to 900 nm. Both have obvious spectral characteristic. According to our results, the largest extinction coefficient appear at blue color, while the largest reflectance appear at yellow and red, which means that those bands are the most sensitive wavelength to detect the change of cadmium concentration in water. This study carries out with optical parameters measurements for optical activity of cadmium compounds specifically for water quality remote sensing for the first time. We conclude that the extinction coefficient and reflectance spectrums we obtained are reasonable, and the results can be used as the base parameter in the remote sensing inversion model for cadmium contents in water, which provides a breakthrough on using remote sensing technique to extract the heavy metal contents in water. Obtained these two optical parameters in this paper can provide powerful reference for band selection of the remote sensing image, which is used to extract cadmium contents in water, as well as provide the necessary important parameters of the remote sensing inversion model of cadmium contents in water..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4006 (2016)
Preparation of Zinc Dibenzyl Dithiocarbamate and Its Spectral Analysis
FENG Shi-hong, JIA Tai-xuan, WU Hong-mei, and GUO Yu
In the study, zinc methyl mercaptobenzimidazole (MMBZ) was synthesized by one-step method. MMBZ was detecued and characterized by FTIR, UV-Vis, XRD, TG-DSC. Its micro-structure and intrinsic regularity were revealed. Chemical bond types into MMBZ molecule were revealed by FTIR. The final product was determined MMBZ. ThIn the study, zinc methyl mercaptobenzimidazole (MMBZ) was synthesized by one-step method. MMBZ was detecued and characterized by FTIR, UV-Vis, XRD, TG-DSC. Its micro-structure and intrinsic regularity were revealed. Chemical bond types into MMBZ molecule were revealed by FTIR. The final product was determined MMBZ. There absorption peaks were detected by UV-Vis at 219.6, 245.5, 302.2 nm respectively, due to n→σ*, π→π*, π→π* electronic transitions, led by S—C, benzene and five element heterocyclic in MMBZ molecule. It could provide experimental basis with enterprise to test MMBZ product quality and speculate its structure. It was shown that MMB was a ligand of MMBZ, and its basic structure of MMB was retained still by XRD spectra. The structure of MMBZ molecule was amorphous. Two kinds of information were detected with TG-DSC as quality change and thermal effect. There were five absorption peaks of 67.5, 155.3, 253.7, 324.8, 391.3 ℃, due to impurity solvent decomposition peak, phase transition peak and decomposition of MMBZ respectively. The scheme of one step preparation of composite environment-friendly rubber antioxidant MMBZ was feasible. The structure of MMBZ could be speculated by results of its detecting. It could provide the basis of experimental data on association MMBZ performance, exploring its anti-aging mechanism and extending the scope of MMBZ application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4013 (2016)
Spectrophotometric Determination of the Amount of Zinc on the Imprint Left on Hands by Zinc Coatings with 5-Br-PADAP as the Chromogenic Reagent
YANG Rui-qin, XING Zhuo, and ZHOU Hong
Spectrophotometric determination of the amount of zinc on the imprint left on hands by zinc coatings with 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP) as a chromogenic reagent has been studied in this paper. The effect of reaction conditions including volume and pH of buffer solution as well as the volSpectrophotometric determination of the amount of zinc on the imprint left on hands by zinc coatings with 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP) as a chromogenic reagent has been studied in this paper. The effect of reaction conditions including volume and pH of buffer solution as well as the volume of chromogenic reagent on the determination has also been studied. On the optimized condition, the standard curve of zinc has been established and the amount of zinc on the imprint left on hands by zinc coatings with different contact time and time elapse has been determined separately. As the results shown, the optimized reaction condition is 4 mL of boric acid and borax buffer solution(pH 8.0), 0.2 mL of 5-Br-PADAP with the concentration of 1 g·L-1 and 1 mL of Triton-X-100 with volume fraction of 10%. Under this circumstance, high linearity of zinc is followed between 0 and 14 μg and the regression equation of zinc is y=1.851 34x+0.002 29. The amount of zinc on the imprint left on hands by zinc coatings, ranging from 0.425 to 2.377 μg·cm-2, increases with contact time from 10 second to 5 min and varies insignificantly from 5 to 10 min. The amount of zinc left on hands declines sharply with time elapse from 0 h to 2 h, and then slowly from 2 to 7 h. The amount of zinc within 7 h is only 0.188 μg·cm-2, which is 90% lower than that of 0 h. Therefore, it is suggested that the trace metal detection should be conducted as soon as possible. Besides, the amount of zinc on the imprint left on hands by zinc coatings with different time elapse is not entirely comply with the intensity of imprint left by zinc coatings. This demonstrates that the amount of zinc on hands is not the only factor influencing the intensity of imprint on hands with different time elapse. Additionally, it also proves the hypothesis that zinc in the complex of zinc and protein can be captured and bonded by 5-Br-PADAP resorting to a stronger chelating capacity in the experiment for the first time. The application of the combined methods in a macro and micro view is useful for study in mechanism of influencing factors in trace metal detection, which lays foundations l for further researches..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4017 (2016)
Distinguish and Quality Estimation of the Leaves of Alstonia scholaris (L.) R. Br. from Different Harvest Time Based on the UV-Vis·FP and HPLC·FP
YANG Ni-na, ZHANG Ji, ZHAO Yan-li, WANG Yuan-zhong, and ZHAO Ying-hong
UV-Vis and HPLC fingerprint of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. were establish the for identification and quality evaluation to promote the development of Dai Medicine modernization. The optimal extraction condition was used to obtain UV - vis data of different harvest time which wUV-Vis and HPLC fingerprint of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. were establish the for identification and quality evaluation to promote the development of Dai Medicine modernization. The optimal extraction condition was used to obtain UV - vis data of different harvest time which were deducted background and eight spot smooth, were collected to make the principal component analysis in SIMCA-P+11.5, identifying the samples quickly with the first three principal component three-dimensional diagram. The HPLC fingerprint were obtained with Agilent ZORBAX Eclipse XDB C18 (250×4.6 mm, 5 μm) chromatographic column with the mobile phase of acetonitrile (B) - water (contain 0.1% formic acid) (A) for gradient elution (0～5 min, 5% B; 5～35 min, 5% B→26% B; 35～40 min, 26% B→56% B). The wavelength was set at 287 nm and the column temperature was maintained at 30 ℃. The flow rate was 1.0 mL·min-1 and the injection volume was 7 μL. The HPLC fingerprint of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. was analysised by cluster analysis to quality evaluation. Research findings showing: (1) The UV-Vis spectrogram of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. were divided into three parts according to the absorption peak position and amplitude of variation. The first was 235 to 400 nm, the second was 400 to 500 nm, and the third was 500 to 800 nm. In the first part, absorption peak were focused on 270, 287 and 325 nm, which can reflect the fingerprint character for the high absorbance and amplitude of variation. Absorption peak were distributed in 410 and 464 nm in the second part, absorbance and amplitude of variation were lower than the first part. There was a bigger absorption peak at 665 nm in the third part, but the absorbance had no difference. The UV-Vis data of different harvest time were gathered to make the principal component analysis, the result was that the samples of same month were concentrated distribution, but different month samples were dispersed distribution. (2) HPLC fingerprint were divided into three categories through hierarchical cluster analysis, 3, 4, 5 and 7 month were the first category, 6, 8, 9 month samples were second category, the others were third category. Chemical composition and content of the same category samples were similar, but the different category samples had a obvious difference, more important is that the third category samples content was the highest. Combining UV-Vis FP and HPLC FP can identify and evaluate quickly the samples of different harvest time of the leaves of Alstonia scholaris (L.) R. Br. The optimal harvest time of Alstonia scholaris (L.) R. Br. was from October to next February, which was the coldest season in the Dai calendar..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4021 (2016)
Study on Identification of Immature Corn Seed Using Hyperspectral Imaging
YANG Xiao-ling, YOU Zhao-hong, and CHENG Fang
The seed maturity, which is one of the important factors that affect seed vigor, is an important quality index. During seed sorting, separating mature seeds from immature seeds can improve the vigor of seed lot and keep vigor consistency. Hyperspectral imaging that covered the range of 400~1 000 nm was used to find outThe seed maturity, which is one of the important factors that affect seed vigor, is an important quality index. During seed sorting, separating mature seeds from immature seeds can improve the vigor of seed lot and keep vigor consistency. Hyperspectral imaging that covered the range of 400~1 000 nm was used to find out the sensitive bands reflecting corn seed maturity, and corresponding images were employed to classify the immature corn seeds. Principal component analysis (PCA) algorithm was adopted to analyze the hyperspectral image. PC2 of PCA had the greatest difference between immature and mature areas on the seeds, therefore, the weighted coefficients of PC2 was selected to extract sensitive wavebands (501 nm). Regions of interest (ROI) from mature and immature area of 70 immature kernels was selected for mean spectra calculation. Partial least square regression (PLSR) algorithm was employed to analyze the spectra of ROI and extract wavelength related to maturity (518 nm). Band ratio algorithm and Kruskal-Wallis test were used to select the best band ratio that had the biggest difference between mature and immature areas (640 nm/525 nm). 864 kernels of corn seed were analyzed by gray images of the selected wavelengths as well as band ratio images. Results showed that the light color regions of the seed crown were misidentified as immature region when the images of selected single band wavelengths were used, while the band ratio image of 640 nm/525 nm could be identified correctly. The immature seeds can be separated from the mature seeds according to the area ratio of segmented immature region to the whole kernel. The correct recognition rate was 93.9%. Using the grey images of selected band ratio can differentiate immature corn seeds from mature seeds effectively, which provide a theoretical reference for the development of seed sorting device in further work..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4028 (2016)
Study on Nondestructive Detecting Gannan Navel Pesticide Residue with Hyperspectral Imaging Technology
LI Zeng-fang, CHU Bing-quan, ZHANG Hai-liang, HE Yong, LIU Xue-mei, and LUO Wei
Hyperspectral imaging technology is a rapid, non-destructive, and non-contact technique which integrates spectroscopy and digital imaging to simultaneously obtain spectral and spatial information. Hyperspectral images are made up of hundreds of contiguous wavebands for each spatial position of a sample studied and eachHyperspectral imaging technology is a rapid, non-destructive, and non-contact technique which integrates spectroscopy and digital imaging to simultaneously obtain spectral and spatial information. Hyperspectral images are made up of hundreds of contiguous wavebands for each spatial position of a sample studied and each pixel in an image contains the spectrum for that specific position. With hyperspectral imaging, a spectrum for each pixel can be obtained and a gray scale image for each narrow band can be acquired, enabling this system to reflect componential and constructional characteristics of an object and their spatial distributions. In this study, hyperspectral image technology is used to discuss the application of hyperspectral imaging detection technology of Jiangxi navel orange surface of different concentrations of pesticide residue changes with time relationship. The pesticide was diluted to 1∶20, 1∶100 and 1∶1 000 solution with distilled water. A 1×2 matrix of dilutions was applied to each of 30 cleaned samples with different density pesticide residue. After 0, 4 and 20 d respectively, hyperspectral images in the wavelength range from 900 to 1 700 nm are taken. The characteristic wavelengths are achieved by using principal component analysis (PCA) and the PC-2 image based on PCA using characteristic wavelengths (930, 980, 1 100, 1 210, 1 300, 1 400, 1 620 and 1 680 nm) as the classification and recognition of image. Based on these 8 characteristic wavelengths for a second principal component analysis, the application of PC-2 image and appropriate image processing methods for different concentrations and different days of placing pesticide residues in non-destructive testing were applied. Using hyperspectral imaging technology to detect three periods a higher dilution of the fruit surface pesticide residues are more obvious. This research shows that the technology of hyperspectral imaging can be used to effectively detect pesticide residue on Gannan navel surface..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4034 (2016)
Study of the Impact of Sample Thickness on Thin Film Method X-Ray Fluorescence Spectrum Measurement
GAN Ting-ting, ZHANG Yu-jun, ZHAO Nan-jing, YIN Gao-fang, XIAO Xue, ZHANG Wei, LIU Jian-guo, and LIU Wen-qing
The mixed samples of nylon film enrichment of Cr, Pb and Cd three elements and glass fiber membrane filter were as the research object. With the method of superposition of membrane filter, the XRF spectra were measured under different thin film samples thicknesses. According the changes of characteristic XRF of Cr, Pb The mixed samples of nylon film enrichment of Cr, Pb and Cd three elements and glass fiber membrane filter were as the research object. With the method of superposition of membrane filter, the XRF spectra were measured under different thin film samples thicknesses. According the changes of characteristic XRF of Cr, Pb and Cd elements in the mixed sample and Ca, As and Sr elements in glass fiber membranes, the effects of sample thickness on thin film method XRF spectrum measurement were studied. The study results showed that the effects of thin film sample thickness on the fluorescent properties of elements with characteristic spectral lines in different energy ranges were different. The energy of characteristic spectral lines was greater, the loss of element characteristic X-ray fluorescence when it passed through membrane and reached detector was less. But matrix effect caused by thin film sample thickness increase was stronger with the energy of characteristic spectral lines greater. The background fluorescent intensity in corresponding characteristic spectral line location was greater. So the impact of matrix effect caused by sample thickness increase on thin film method XRF spectrum measurement sensitivity was greater. For elements with low energy characteristic spectral lines (energy≤7 keV), the way of increasing thin film sample thickness in order to increase the mass-thickness concentration of component measured, can not effectively improve the sensitivity of thin film method XRF spectrum measurement. And thin film samples thickness within 0.96 mm is conductive to the measurement and analysis of XRF spectrum. For element with higher energy characteristic spectra lines(energy＞7 keV), the sensitivity of XRF spectrum measurement can be appropriately increased by the way of increase thin film sample thickness in order to increase the mass-thickness concentration of component measured. And thin film samples thickness within 0.96～2.24 mm is more conductive to the measurement and analysis of XRF spectrum. The study provides an important theoretical basis for thin sample preparation and enrichment technology of thin film method X-ray fluorescence spectrum analysis the atmosphere and water heavy metal..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4039 (2016)
Research Method and Spectral Analysis of Ancient Polychromatic Silicate Artifacts
WANG Xue-pei, ZHAO Hong-xia, LIU Song, and LI Qing-hui
The spectral properties, chemical compositions and phases of materials constituting the surface of 5 ancient polychromatic silicate artifacts have been analyzed non-invasively with self-built multispectral imaging system, X-ray fluorescence spectrometer (XRF) and laser Raman spectrometer (LRS). Based on spectral responThe spectral properties, chemical compositions and phases of materials constituting the surface of 5 ancient polychromatic silicate artifacts have been analyzed non-invasively with self-built multispectral imaging system, X-ray fluorescence spectrometer (XRF) and laser Raman spectrometer (LRS). Based on spectral response in multispectral images, materials constituting the surface of 5 samples can be divided into different areas, and most of blue, green, purple areas with fluorescence behavior are also mapped. The results of XRF indicate that the chemical compositions of areas are different, but the major compositions of them are SiO2, PbO, BaO. 5 samples mainly belong to PbO-BaO silicates. The coloring agents of all areas with fluorescence behavior are Cu ions. A variety of mineral phases including vitreous phase, Chinese blue, Chinese purple, quartz, hematite, lead carbonate, amorphous carbon and so on, are also identified by LRS. Chinese blue and Chinese purple can emit infrared radiation when excited by visible LED. The result of LRS is verified by X-ray diffraction (XRD). Combining the multispectral imaging area-measurement technique used to research paintings, and XRF, LRS which are usually used to analyze chemical composition of silicate artifacts, the present research proposes a more efficient and non-invasive research method to analyze ancient polychromatic silicate artifacts. Spectral characteristic and chemical composition of the sample are connected when spectral images, X-ray fluorescence spectra and Laser Raman spectra are combined. It has great significance for increasing efficiency of analysis, enhancing the overall understanding of silicate artifacts and decreasing risk of damage..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4045 (2016)
Research on the Reaction Dynamics between Peroxynitrite and Tyrosine Catalyzed with Mimic Enzyme through Flow Injection Analyzer
AN Xue-jing, LUO Yun-jing, and ZHANG Chen-yang
As a highly active free radical in vivo, peroxynitrite can damage various biological macromolecules and cause a series of major diseases, which is of great significance to determine its content and reactive mechanism. It is very difficult to capture the dynamic process of peroxynitrite due to its active property and faAs a highly active free radical in vivo, peroxynitrite can damage various biological macromolecules and cause a series of major diseases, which is of great significance to determine its content and reactive mechanism. It is very difficult to capture the dynamic process of peroxynitrite due to its active property and fast reacted rate. In this paper, we firstly explored the kinetic characteristics of peroxynitrite and tyrosine with the presence of Hemoglobin and Hemin by using flow injection analyzer. The results showed that the oxidation processes of peroxynitrite and tyrosine catalyzed with hemoglobin and hemin were in accordance with Michaelis-Menten’s dynamics law; Based on the Michaelis constant (Km) and the maximum initial rate (Vmax), we deduced the reaction mechanism that peroxynitrite, catalyzed by mimic enzymes, directly oxidized tyrosine combined with mimic enzymes, rather than decomposed to ·OH and O－2·; In addition, we detected the rate constant of the reaction catalyzed by these two kinds of enzymes at different temperature and pH, resulting that the optimum conditions of hemoglobin to catalyze this system were 25 ℃ and pH 8, the rate constant was 1.035×106 mol·L-1·s-1, while hemin was 37 ℃ and pH 9.5, the rate constant was 6.842×105 mol·L-1·s-1; Comparing the kinetic parameters, KmHb(4.46 μmol·L-1)VHeminmax(0.026 ΔIF/s), we discovered that the rate constant of hemoglobin in optimum condition was greater than that in hemin, and the catalytic activity of hemoglobin was higher than that of hemin. All these results have provided kinetic parameters for the study of determining the content of peroxynitrite and exploring its reaction mechanism with enzymatic method. It also laid a theoretical foundation for developing new diagnosis technology to prevent and cure diseases caused by free radicals in vivo..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4052 (2016)
The Study of Spectral Characteristic of Coal Ash from Different Sources with Laser-Induced Breakdown Spectroscopy
SHEN Yue-liang, LU Ji-dong, and ZHANG Bo
The samples with different carbon content are collected for quantitative analysis. One of the normal methods is the ignition of different coals according to the notice of fast ashing method instead of collecting coal ash in boiler. But there are some differences between fast ashing method in laboratory and actual boileThe samples with different carbon content are collected for quantitative analysis. One of the normal methods is the ignition of different coals according to the notice of fast ashing method instead of collecting coal ash in boiler. But there are some differences between fast ashing method in laboratory and actual boiler. It is necessary that the spectral deviation of coal ash from these two sources is studied as a guidance of quantitative analysis in carbon content. In present work, the intensity of the characteristic lines and plasma temperature were compared with different carbon content from these two processes. As a result, Fe, Mg, Al line strength of ash with fast ashing method is stronger and plasma temperature is lower than coal ash in boiler. Principal component analysis was processed, the results show that the difference of Fe, Mg, Al and Si content is the primary factor, and minerals in coal ash with fast ashing method may influence the spectral characteristic. The influence of mineral elements and mineral content on spectra for quantitative analysis with fast ashing method should be noticed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4058 (2016)
Preparation of La2Zr2O7 Powder with Combustion Method and Its Spectral Properties
LIU Xiao-zhen, ZHANG Cheng, CHEN Jie, SHEN Qin-wei, GUO Ling-ling, and XIE Guang
La2Zr2O7 powder was prepared with combustion method with La2O3, Zr(NO3)4 and glycine as raw materials. La2Zr2O7 powders were characterized with ICP-AES, EDAX, XRD, IR and TG-DTA techniques, respectively. Effects of heat treatment temperature on the XRD spectra and IR spectra of La2Zr2O7 powders were studied. The X-ray La2Zr2O7 powder was prepared with combustion method with La2O3, Zr(NO3)4 and glycine as raw materials. La2Zr2O7 powders were characterized with ICP-AES, EDAX, XRD, IR and TG-DTA techniques, respectively. Effects of heat treatment temperature on the XRD spectra and IR spectra of La2Zr2O7 powders were studied. The X-ray diffraction pattern of La2Zr2O7 powder after heat treatment at 600 ℃ has one diffraction peak, and the diffraction peak is quite broad, therefore, the crystal structure of the La2Zr2O7 powder is semi-crystal structure. With the increase of heat treatment temperature, diffraction peaks become gradually sharp and increase. The crystal structure of the La2Zr2O7 powders after heat treatment in 750～800 ℃ are pyrochlore structure. Analysis results of IR spectra of La2Zr2O7 powders after heat treatment in 650～750 ℃ show that the crystal structure of the La2Zr2O7 powders after heat treatment at 750 ℃ is pyrochlore structure, and the analysis results of XRD and IR are the same. Analysis results of TG-DTG of La2Zr2O7 powders show that the crystal structure of the La2Zr2O7 powders are stability in 120～1 600 ℃..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4063 (2016)
Research on Space Target Recognition Algorithm Based on Spectral Information
LI Qing-bo, WU Ke-jiang, and GAO Qi-shuo
Because of ground observation instruments and other factors, we can not recognize the space target only from the external shape in the image. Since the reflection spectrum of the space target is determined by the surface material of space object, spectral analysis technique can be used for classifying the space objectsBecause of ground observation instruments and other factors, we can not recognize the space target only from the external shape in the image. Since the reflection spectrum of the space target is determined by the surface material of space object, spectral analysis technique can be used for classifying the space objects. Based on the K-nearest neighbor algorithm (KNN), a method called adaptive weight k-local hyperplane (AWKH) is proposed in this paper. The main improvement of the algorithm is that weight discrimination is added in the processes of calculating the hyperplane distance between predicted samples. The algorithm constructs a hyperplane model by using the difference between the groups and within group ratio for the weights of features. In order to verify the classification effectiveness and efficiency of the algorithm, this paper carried out four sets of verification experiments. In the first set of experiments, 9 kinds of common materials were extracted from the database of United State Geological Survey. Then 3 kinds of these materials were mixed into multi-class objections. In the second and third sets of experiments, the spectra of four normal space target materials were mixed in different classes. Then these classes were identified from the visible and near-infrared wave bands. In the fourth set of experiments, four square models of hexahedron were classified by the spectra of their surface material. The experimental results indicate that the AWKH algorithm has more advantages in identification accuracy and effectiveness of the complex samples by comparing with the support vector machine (SVM) method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4067 (2016)
Research and Application of Narrowband Polarizing Beam Splitter in the Optical Fiber Communication
LI Mei-xuan, DONG Lian-he, ZHANG Lei, and LENG Yan-bing
In fiber-optic communications, in order to achieve more data channels in the wavelength division multiplexing (WDM) system without changing the modulation wavelength range, a new type of small-sized narrowband polarizing beam splitter was designed. It can be used for data communication network expansion and improve theIn fiber-optic communications, in order to achieve more data channels in the wavelength division multiplexing (WDM) system without changing the modulation wavelength range, a new type of small-sized narrowband polarizing beam splitter was designed. It can be used for data communication network expansion and improve the Signal to Noise Ratio (SNR) of the optical signal. Two kinds new film system designed were deposited on the polarizing beam splitter. One layer is narrowband filter film, while the other layer is polarizing beam splitter film. TFCalc software was used for simulation analysis, and the results shown that the bandwidth of the narrowband filter film was about 0.4 nm, and the permeability of p light from the polarizing beam splitter film was better than 99.8% in the range of 1 530～1 560 nm. Based on the above film system design, two groups film system was made on BK7 optical glass. In the experiment, light through film was spectral analysis with Agilent 8164-A type optical measuring instrument. Experimental results show that the actual bandwidth of the narrowband filter film is better than 0.4 nm, gain flatness is not less than -0.05 dB. It has a narrower bandwidth compared to the existing common 0.8 nm filter film, and it can be realized to increase the amount of data channels in the wavelength division multiplexing system with the same modulation wavelength range. Actual transmittance of p light was 99.6% through polarizing filter film, and it’s slightly lower than the simulated values, but it remains better than the design requirements. Compared to conventional polarizing beam splitter, its optical signal was stronger, and it has a higher SNR. In summary, the polarizing beam splitter has better application value and practical significance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4072 (2016)
Automatic Field Calibration and Analysis of Satellite Based on Hyper-Spectral Ratio Radiometer
LIU En-chao, LI Xin, WEI Wei, ZHAI Wen-chao, ZHANG Yan-na, and ZHENG Xiao-bing
With the demand of calibration technology of high frequency and high precision in terms of the optical remote sensing satellite of China, and the deficiency of the artificial work, the automatic system of hyper-spectral ratio radiometer was developed by investigation the calibration situation of domestic and abroad satWith the demand of calibration technology of high frequency and high precision in terms of the optical remote sensing satellite of China, and the deficiency of the artificial work, the automatic system of hyper-spectral ratio radiometer was developed by investigation the calibration situation of domestic and abroad satellite, then the automatic calibration of satellite sensor was carried out. According to the parameters demand of field calibration and the goal of automation, the ratio radiometer was designed to measure global spectral irradiance by integrating sphere, and the diffuse spectral irradiance was measure by the shelter, so the diffuse-global ratio was calculated by these data. Simultaneity the ground radiation was measured with radiometer optical-lens and the automatic observation of atmospheric and surface radiation characteristics was achieved, In addition, the data pre-processing of real-time and remote transmission were integrated in the system. With the field test on the Dunhuang radiometric calibration sites in 2015, the radiometer worked in an ideal way, and the atmospheric optical parameters and surface reflectance data were acquired, which support the calibration of satellite sensor. The comparison with the traditional measurement was carried, the relative deviation of the surface reflectance is less than 5%, and the absolute deviation of the atmospheric parameters is less than 5% and the diffuse ratio is less than 0.015%. According to the measured data and based on irradiance-based method, the field calibration applied to the band 1~5 of Aqua MODIS, the relative deviation of band 1~4 is less than 1% while the band 57.24%, so the requirement of the automatic calibration of the satellite sensor was satisfied preliminarily..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4076 (2016)
Research of the Raman Signal De-Noising Method Based on Feature Extraction
FAN Xian-guang, WANG Xiu-fen, WANG Xin, XU Ying-jie, QUE Jing, WANG Xiao-dong, HE Hao, LI Wei, and ZUO Yong
To improve time resolution of the Raman measurement system, we need to adopt short scanning time. In this case, the weak Raman signal with vibrational spectrum of the molecular structure is easily to be buried by the high background noise, which influences the further analysis seriously. So it is necessary to de-noise To improve time resolution of the Raman measurement system, we need to adopt short scanning time. In this case, the weak Raman signal with vibrational spectrum of the molecular structure is easily to be buried by the high background noise, which influences the further analysis seriously. So it is necessary to de-noise the raw Raman signals. Conventional methods manage to de-noise signal by means of smoothing or averaging based on the difference between signal and noise in frequency characteristic or statistical features. They are commonly applied in the situation where the background noise is not so strong, and cannot give satisfactory results to the Raman signals with low signal-to-noise ratio. In this paper, the algorithm proposed detects peak positions and get peak half-width based on wavelet transform, and then reconstructs the Raman signals by least square fitting algorithm with characteristic parameters obtained, which extracts the useful signal from high background noise efficiently. In the simulation, the Raman curve fitted by the proposed algorithm was smooth, and the peak positions obtained were accurate, so the signal-to-noise ratio improved significantly. In the experiment, we adopted this algorithm to de-noise the tested Raman signal of Cefuroxime Axetil Tablets and Roxithromycin, respectively. The peak positions, peak half-width and amplitude were obtained and proved to be accurate. Therefore, the useful pure Raman signal could be recovered from the high background noise efficiently by the proposed algorithm, which improved the time resolution of Raman system. Both the simulation and the experiment showed that the proposed method could be easily performed with only a few parameters. Comparing with conventional methods, it could achieve satisfactory results under high background noise and provide accurate and reliable information for further analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4082 (2016)
The Aberration Corrected Grating Spectrometer Based on Adaptive Optics
ZHENG Lian-hui, RAO Chang-hui, GU Nai-ting, and QIU Qi
To study the thermodynamics properties of the solar atmosphere with different height distribution, the imaging grating spectrometer with excellent image quality is one of the important tools to achieve this goal. However, the atmosphere turbulence can not be avoided for the imaging grating spectrometer installed in theTo study the thermodynamics properties of the solar atmosphere with different height distribution, the imaging grating spectrometer with excellent image quality is one of the important tools to achieve this goal. However, the atmosphere turbulence can not be avoided for the imaging grating spectrometer installed in the ground-based solar telescope, and the imaging properties of the grating spectrometer will influenced by the wavefront aberration generalized by the atmosphere turbulence and the wavefront aberration generalized by the optical system adjusting errors and the optical element manufacturing errors. The atmospheric turbulence can be effectively compensated by the Adaptive Optics. To correct the wavefront aberrations of the optical system, a correction method based on Adaptive Optics is proposed, and the experiment validation is carried out to verify the feasibility of the method. The results demonstrate that the correction method proposed can effectively correct the wavefront aberration generalized by the atmosphere turbulence and the optical system aberration. The RMS value is roughly equal to 0.025λ after the Adaptive Optics correction. Besides, it has the virtue of lower the requirement of optical system adjusting errors and optical elements manufacturing errors..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4088 (2016)
Research on Ground Feature’s Polarized Properties with Multi-Spectral and Multi-Angle AirMSPI Data
WANG Xue-qi, JIAO Jian-nan, YANG Bin, JING Xin, ZHAO Hong-ying, and YAN Lei
Polarization is an important characteristic of electromagnetic wave, and using polarization information to study ground features has been proved to be an effective means.Research on ground feature’s polarized properties is an essential part of earth observation. At present, it is in highly need of accuratepolarization Polarization is an important characteristic of electromagnetic wave, and using polarization information to study ground features has been proved to be an effective means.Research on ground feature’s polarized properties is an essential part of earth observation. At present, it is in highly need of accuratepolarization sensors globally. AirMSPI , (Airborne Multiangle SpectroPolarimetric Imager) as a new airborne polarized sensor, can obtain multi-band and multi-angle polarization data, and the spatial resolution can reach to ~10 meters. Using the experimental data of Tracy in the year of 2013, this paper analyzes the varying pattern of DOLP (Degree of Linear Polarization) as well as pBRF(polarized Bidirectional Reflectance Factor) in 470 nm, 660 nm, 865 nm bands and 9 view zenith angles.The result shows that, forward scattering of ground features contains plenty of polarized radiation, and ground features present strong non-lambertian effect near principal plane of incidence. DOLP and pBRF has strong correlation to relative position between incidence and view angle. DOLP reaches the maximum value when two directions are perpendicular while pBRF increases with larger view zenith angle. Because of atmospheric effect, radiance of blue band contains most polarized light. However, red and infrared band can attenuate atmospheric molecular polarization scattering effectively, thus contain more polarization details of ground features.Water, artificial structure, residential area, bare soil and vegetation show distinct polarization characteristics,and can be clearly identified. Due to depolarization effect from multi-scattering effect, DOLP and reflected radiation intensity have highly negative correlation, with correlation coefficient generally more than -0.8. AirMSPI sensor can provide high-quality polarization data, as a strong verification to ground-based and satellite-based polarization data, and support parameters inversion of atmosphere and ground features..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4094 (2016)
Quantitative Analysis of Heave Mental Ion Based on Portable NIR Spectrometer
ZHANG Yi-ting, WANG Cui-cui, FAN Meng-li, CAI Wen-sheng, and SHAO Xue-guang
By virtue of the characters of rapid analysis and simple pretreatment, near infrared reflectance spectroscopy technique is widely used in agriculture, medicine, environment, petrochemical and other fields. To satisfy the rapid on-site identification and analysis, portable near-infrared spectrometers have gained more anBy virtue of the characters of rapid analysis and simple pretreatment, near infrared reflectance spectroscopy technique is widely used in agriculture, medicine, environment, petrochemical and other fields. To satisfy the rapid on-site identification and analysis, portable near-infrared spectrometers have gained more and more attention. Because near infrared reflectance spectroscopy technique also is a green tool for multi-component analysis, the paper aims at investigating the feasibility for simultaneous quantitative analysis of various heavy metal ions in dilute solution using portable near infrared spectrometer. First, amino modified polymerized starch was used as adsorbent to enrich nickel ions and copper ions in diluted solution. Then, the diffuse reflectance spectra of amino modified polymerized starch samples were measured directly by portable near-infrared spectrometer. Furthermore, with the help of spectral preprocessing methods and partial least-squares regression, quantitative models were built from the near infrared diffuse reflectance spectra of amino modified polymerized starch enriched with heavy metal ions and reference concentrations. At last, the stability of the models was proved through cross validation and external validation. The results show that nickel ions and copper ions in diluted solution can be efficiently enriched by amino modified polymerized starch in the presence of other interfering ions. The adsorption rates for nickel ions and copper ions are 99.5% and 99.8%, respectively. Two robust models can be achieved after spectra processing and partial least squares regression. The spectra processing methods contains Continuous wavelet transform and multiplicative scatter correction combined with Savitzky-Golay. The obtained corresponding correlation coefficients of the two robust models are 0.981 9 and 0.965 4, respectively. Thus, simultaneous quantitative analysis of nickel ions and copper ions in the mixed diluted solution was achieved, and the detectable concentrations of nickel ions and copper ions are both as low as 3.0 mg·L-1. The method not only improves the sensitivity of near infrared reflectance spectroscopy technique, but also demonstrates the feasibility for simultaneous quantitative determination of various heavy metal ions by using portable near infrared spectrometer. Moreover, the method may be a useful exploration to further broaden the application of near infrared reflectance spectroscopy technique..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4100 (2016)
The Snapshot Imaging Spectrometer with Image Replication Based on Wallaston Prism
PEI Lin-lin, XIANGLI Bin, LIU Yang-yang, L Qun-bo, and SHAO Xiao-peng
In this paper, a kind of snapshot imaging spectrometer is designed by using image replication based on Wollaston prism. The system includes telephoto lens, collimator lens, Wollaston prism, the imaging lens and compensation filters. With this optical system, we can obtain two-dimensional information at different waveleIn this paper, a kind of snapshot imaging spectrometer is designed by using image replication based on Wollaston prism. The system includes telephoto lens, collimator lens, Wollaston prism, the imaging lens and compensation filters. With this optical system, we can obtain two-dimensional information at different wavelengths of the same target through one time exposure. When Light beam is passing Wollaston prisms, in order to make sure that the different wavelengths will not overlap, the Wollaston prism needs to be designed with relatively large beam splitting angle. Then the incidence angle of the imaging lens is relatively large. It will increase the difficulty of the imaging lens design. We design, analyze the principle and the characteristics of the snapshot imaging spectrometer using image replication based on Wollaston prism, and design a complete set of imaging spectrometer system. The structure is complex; the aperture of the optical system must be well matched. In order to make sure that we can obtain good image quality through the single lens, but also the whole system, we design the telephoto lens which is imaging telecentric structure, the collimator lens which is objective telecentric structure. We use the multiple structures in ZEMAX to optimize the 16 spectral bands. At 56 lp·mm-1, the MTF is close to the diffraction limit, the RMS of the SPT is in the Airy disk, proving good image quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4105 (2016)
Research on the Phase-Shifted Fiber Bragg Grating Spectra under Dynamic Strain Fields
WANG Zheng-fang, WANG Jing, and SUI Qing-mei
Fiber optic sensing technology has been widely used for acoustic emission (AE) measurement in aerospace and geotechnical engineering due to the advantages of immunity to electro-magnetic interference, high accuracy, and multiplexing capacity. As for the fiber Bragg grating based on AE measurement system, traditional efFiber optic sensing technology has been widely used for acoustic emission (AE) measurement in aerospace and geotechnical engineering due to the advantages of immunity to electro-magnetic interference, high accuracy, and multiplexing capacity. As for the fiber Bragg grating based on AE measurement system, traditional efforts have been made to study the spectra of Fiber Bragg Grating under AE signal. While this paper focused on phase-shifted fiber Bragg grating (PS-FBG) which is a new type fiber Bragg grating, and investigated the spectra of under dynamic strain field generating with an AE signal. A dynamic strain sensing model of PS-FBG was built based on the transfer matrix theory, and a cosine exponential attenuation function was utilized to simulate the dynamic strain field. Then the effects of amplitude, sampling time, exponential attenuation coefficient, frequency and wavelength of AE signal on the spectra of PS-FBG were studied in detail using numerical simulation. The result demonstrate that the spectra of PS-FBG changes periodically with frequency and different sampling time, especially the peak wavelength of the transmission window in the PS-FBG spectrum shifts periodically; and the increase of amplitude mainly contribute to more harmonic peaks in the reflected spectrum. The attenuation coefficient affects the spectrum of PS-FBG within certain range. And the AE wavelength affect the spectrum of PS-FBG when it is between 0.1 to 2 L, beyond the range, the spectrum of PS-FBG has minor variation with the AE wavelength. Finally, dynamic strain experiments were conducted, and the spectrum of PS-FBG under continuously vibration signal with different amplitude and frequency were logged for analysis. The experimental results agree well with simulation, which indicate that under different dynamic strain fields generated by AE signal, the spectra of PS-FBG are different, while the variation of spectra follows certain laws. This paper provides theoretical support for the AE measurement system on the basis of PS-FBG..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4113 (2016)
Structure Effect on K Shell Fluorescence Parameters at Bis-4-Bromobenzyl-1,2,4-Triazol-3-Ones
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In this study; the effect of the electron density over the Br atoms raising with increasing number of CH2 group using the results of the K X-ray cross-sections and average fluorescence yields of bromine in quaternary-imidazole ring. In the experimental set-up, 50 mCi 241Am source and a collimated Ultra-LEGe detector weIn this study; the effect of the electron density over the Br atoms raising with increasing number of CH2 group using the results of the K X-ray cross-sections and average fluorescence yields of bromine in quaternary-imidazole ring. In the experimental set-up, 50 mCi 241Am source and a collimated Ultra-LEGe detector were used. The electron density on the Br atoms raises according to the number of the CH2 groups on the contrary of the inductive effect. The decreasing of the X-ray fluorescence parameters is interested with the increasing the electron density of Br atoms..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4120 (2016)
K Shell Fluorescence Parameters by Impact of 5.96 keV Photons on Ti and Its Compounds
O.K. KKSAL, G. APAYDIN, and E. CENGZ
K shell fluorescence parameters of pure Ti and some of its compounds have been determined experimentally using an Ultra-LEGe detector with resolution 150 eV at 5.9 keV. The samples were excited 5.96 keV photons emitted from a 55Fe radioisotope source with 50 mCi activity. The experimental values of the K shell fluorescK shell fluorescence parameters of pure Ti and some of its compounds have been determined experimentally using an Ultra-LEGe detector with resolution 150 eV at 5.9 keV. The samples were excited 5.96 keV photons emitted from a 55Fe radioisotope source with 50 mCi activity. The experimental values of the K shell fluorescence parameters have been compared with the experimental and theoretical values available in the literature for pure Ti..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4125 (2016)
Simulating the Three-Dimensional Image of Cold Atomic Cloud
PENG Yu
We propose a scheme for accurately simulating of the three-dimensional image of cold atomic cloud, which is more intuitive and stereoscopic than former two-dimensional image by probe laser. We have realized simulating of cold atomic cloud. The number of trapped atoms is about 108. The atomic cloud is about the geometriWe propose a scheme for accurately simulating of the three-dimensional image of cold atomic cloud, which is more intuitive and stereoscopic than former two-dimensional image by probe laser. We have realized simulating of cold atomic cloud. The number of trapped atoms is about 108. The atomic cloud is about the geometric three-dimensional shape. Tri-axial ellipsoid with distinct semi-axis lengths Ｒｘ＝1.06 mm, Ry＝1.06 mm, Rz＝0.57 mm, and the three-dimensional image of cold atomic cloud was simulated for the first time..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4130 (2016)
Study on Emission Spectrum of OH Radicals in a Combination System of Pulsed Discharge Plasma and Activated Carbon
GUO He, WANG Hui-juan, JIA Yuan-yuan, SUN Chen-jing, ZHOU Guang-shun, WU Qiang-shun, and YI Cheng-wu
Based on the higher oxidation potential of OH radicals (2.8 V), the synergetic effect of pulsed discharge plasma (PDP) and activated carbon (AC) and the advantages of emission spectroscopic detection, such as easy operation, high accuracy and high sensitivity, the relative emission spectra of the OH radicals generated Based on the higher oxidation potential of OH radicals (2.8 V), the synergetic effect of pulsed discharge plasma (PDP) and activated carbon (AC) and the advantages of emission spectroscopic detection, such as easy operation, high accuracy and high sensitivity, the relative emission spectra of the OH radicals generated in the PDP/AC system with oxygen flow were measured by the emission spectroscopic detection technique and the spectral intensity of the OH radicals was used to represent the relative amount of the OH radicals formed in the reaction system. The effect of additive amount of the AC, peak pulse voltage and electrode gap on the relative emission spectrum intensities of OH radicals were investigated to illustrate the crucial factors for the OH radicals formation in the PDP/AC system. In addition, the formation of OH radicals in the two liquid phases of distilled water and acid orange 7 (AO7) solution in the sole PDP system and the PDP/AC system were investigated to testify the synergetic mechanism of PDP/AC and the oxidization of OH radicals on the organic compounds in the reaction system. The obtained results showed that the catalytic effect of the AC increased with the increase of the additive amount of the AC in the PDP system, which led to the increase of the relative emission spectral intensities of the formed OH radicals in the synergistic system; higher peak pulse voltage was in favor of the energy input in the discharge system and then enhanced the formation of OH radicals; increase of the electrode gap led to the decrease of energy efficiency in the reaction system and the decrease of the formed OH radicals in the PDP/AC system; the formation of OH radicals in the PDP/AC system was higher than that in the sole PDP system both in the distilled water and in the AO7 solution; the formation of OH radicals in the distilled water was higher than those in the AO7 solution no matter the reaction system was the sole PDP system or the PDP/AC system. The two results indicated that the AC addition was beneficial to the formation of OH radicals in the PDP system and the OH radicals had an important effect on the organic compounds degradation both in the sole PDP system and in the PDP/AC system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4135 (2016)
Studies on the Interaction of Perfluorononanoic Acid with Human Serum Albumin by Multi-Spectroscopic, Molecular Docking and Isothermal Titration Calorimetry Techniques
HU Tao-ying, HUANG Fang, ZHOU Shan-shan, and LIU Ying
Perfluorononanoic acid (PFNA) is the third most frequently detected in serum among all perfluoroalkyl acids (PFAAs) which is a kind of toxic emerging environmental contaminant. The influence of PFNA on the conformation and even function of human serum albumin (HSA) is still just at the beginning of research. The attempPerfluorononanoic acid (PFNA) is the third most frequently detected in serum among all perfluoroalkyl acids (PFAAs) which is a kind of toxic emerging environmental contaminant. The influence of PFNA on the conformation and even function of human serum albumin (HSA) is still just at the beginning of research. The attempt of this paper was to completely elucidate the interaction mechanism of PFNA with HSA by means of multi-spectroscopic, molecular docking and isothermal titration calorimetry (ITC) techniques. The inner filter effect of all fluorescence data in the paper was eliminated to get accurate binding parameters. The results showed that the fluorescence of HSA was quenched by PFNA through a combined quenching procedure of dynamic and static quenching. Through site marker competitive experiments, subdomain IIA of HSA had been assigned to possess the high-affinity binding site of PFNA. Furthermore, molecular docking reconfirmed that PFNA was bound in subdomain IIA mainly through polar force, hydrophobic interaction and halogen-bond, and the calculated free energy was -26.54 kJ·mol-1 which indicated that the PFNA molecule exhibited large binding affinity towards HSA. The thermodynamic characterizations of two different classes of binding sites by ITC displayed that the first class with a higher affinity constant was dominated by an enthalpic contribution due to electrostatic interactions and halogen-bond, whereas the second class with a lower affinity constant was preponderated by hydrophobic interaction. The three-dimensional fluorescence revealed that the conformation of HSA was changed and the hydrophobicity of the Trp and Tyr residues microenvironment increased after formation of PFNA-HSA complex. The alterations of the protein secondary structure were quantitatively calculated from circular dichroism (CD) spectroscopy with reduction of α-helix content about 14.3%, β-sheet 5.3%, β-turn 3.5%, and augment in random content from 14.4% to 37.5%. Above results revealed that the binding of PFNA with HSA can alter the secondary structure of HSA, further probably affecting HSA physiological function. The results can provide insights with the binding mechanism of PFNA with HSA and salient biophysical and biochemical clues on elucidating the transport and distribution of PFNA in vivo..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 4141 (2016)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 12, 1 (2016)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20