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2017 Vol. 37, No. 03
Published: 2017-03-01

 
       光谱学与光谱分析
665 The Study of UV Scattering Polarization Properties of Spherical Particles of Haze
ZHAO Tai-fei, WANG Chan, KE Xi-zheng
DOI: 10.3964/j.issn.1000-0593(2017)03-0665-07
With the rapid development of economy and society in our country, atmospheric haze has become a prominent environmental issue. Measuring haze particles is also important. Polarized ultraviolet light is scattered by atmospheric haze particles, the changes of scattered light polarization state(Stokes vector and the degree of polarization) in atmospheric haze can reflect the physical properties of the particles (particle size and the complex refractive index, etc.). Based on Mie scattering theory, line-of-sight and non-line-of-sight of a single UV scattering model is established. On one hand, the effects of the physical properties of the single and chain-structure spherical particles for the UV light polarization properties are studied. On the other hand, based on Monte Carlo Simulation, the impacts of haze particle concentration on polarization state at a fixed particle size distribution are discussed. The simulation results show that: with the particle size of single spherical increasing, the scattered light intensity in Stokes vector (Is) is significantly enhanced. Is shows a trend of first increase then decrease with the increase of the complex refractive index’s imaginary part. The degree of polarization is constantly increasing with the increase of the complex refractive index’s imaginary part and the imaginary part of the complex refractive index is small, the degree of polarization trend of fast increase. With the concentration of particles in haze increasing when the distribution of particle size is a fixed value, haze particles scattering coefficient, extinction coefficient and absorption coefficient showed a linear increase, while Is is reduced after the first increases. For chain-structure spherical particles, with the increase of the number of particles, Is shows a tendency to increase. As the same time, degrees of polarization distinguish whether the chain-structure spherical particles are made up by the same spherical particle. In the chain-structure consisted of same spherical particles, Is increases linearly with the increase of the number of particles and the degree of polarization does not change. The Is under the chain-structure consisted of different spherical particles can distinguish particles’ physical properties according to the changing trend of scattering light polarization state.
2017 Vol. 37 (03): 665-671 [Abstract] ( 217 ) PDF (3599 KB)  ( 552 )
672 Advances in Spectroscopic Characters of Space Objects
XU Can1, ZHANG Ya-sheng1, ZHAO Yang-sheng1, LI Peng2
DOI: 10.3964/j.issn.1000-0593(2017)03-0672-07
Spectroscopic characters of space objects are basic optical attributes which could stand for the material types of space objects. By comparing actual spectral characteristics with that obtained in the lab, the types of space materials can be identified, which is beneficial for the analysis of working states and compositions of space objects. Aiming at the problems of spectrum measurement and material information retrieval, the spectroscopic theory, retrieval methods and reddening effect of space objects spectrum are analyzed in this paper. The contributions on the spectrum from 350 to 2 500 nm from vibrational spectrum and electrical spectrum are investigated based on solid spectrum characters. Three methods commonly used in space objects material identification based on spectrum characters are studied, which are artificial neural network algorithm, particle swarm optimization algorithm and spectrum unmixing algorithm, and the features including spectrum reflectance and its derivative, center displacement are discussed. Reddening effect in spectrum measurement is studied, and it is shown that the reddening effect is related to the deoxidizing effect when some material access to space environments. The loose chemical bonds are formed due to the separation of oxygen and the combination of contaminations in space, which results in more absorptions of light energy and the higher slope of reflectance at longer wavelength that is named reddening effect. The reflectance of spectrum can be used to analyze material aging problems on the surface of satellite material under the continuous influences of harsh space environment, including chemical or physical changes, which are favorable for repairing existing satellite or launching new satellite.
2017 Vol. 37 (03): 672-678 [Abstract] ( 208 ) PDF (1450 KB)  ( 171 )
679 Study on Dissociation Properties and Spectra of Halon 1301 in External Electric Field
LIU Yu-zhu1,2, LI Xiang-hong3, WANG Jun-feng1, GUAN Yue1,2, JIN Feng4, QIN Chao-chao5
DOI: 10.3964/j.issn.1000-0593(2017)03-0679-06
Halon-1301 (CF3Br) can make Br radicals with UV radiation, which poses a great threat to the ozone layer in the atmosphere. Necessary methods should be taken for the degradation of the exhausts of Halon-1301. In this paper, density functional (DFT) theory at B3LYP/6-311G++(d,p) level are employed for the study of dissociation properties and spectra of Halon-1301 in external electric field, including bond length, total energy, HOMO-LUMO energy gap, infrared spectra and dissociation potential energy surface (PES). The obtained results show that, with gradually increasing the external field from 0 to 0.03 a.u. along the molecular axis Z (C—Br bond direction), the total energy decreases, while the dipole moment decreases at the beginning and then increases. With the climbing of the field, HOMO-LUMO energy gap increases, and C—Br bond length increases while C—F bond length decreases. The variations of vibrational frequency and intensity of molecular IR spectra in external electric field are also investigated. Further studies show that with increasing the external electric field from 0 to 0.03 a.u., the dissociation PES along C—Br bond becomes unbound with disappearing of the barrier for the dissociation. The external electric field of 0.03 a.u. is sufficient to induce the degradation of CF3Br with C—Br bond breaking. Such results provide an important reference for the degradation of Halons via the external electric field.
2017 Vol. 37 (03): 679-684 [Abstract] ( 252 ) PDF (2245 KB)  ( 107 )
685 Radiation Temperature Measurement Technology Based on the Basis of Spectral Emissivity Function
ZHU Ze-zhong1,2, SHEN Hua1,2*, WANG Nian1,2, ZHU Ri-hong1,2
DOI: 10.3964/j.issn.1000-0593(2017)03-0685-07
In recent years, with the rapid development of the national defense, industry, technology and other fields, whether it is for the power transmission systems or for the steel smelting and new high-tech industry, temperature measurement has been of important significance. Especially in the high temperature and accompanied by the demand for transient (less than lus)temperature measurement occasion, multi spectral radiation temperature measurement method has been widely used. Multi spectral thermometry is selected by the measured target multiple wavelengths radiation information, the mathematical model of emissivity and wavelength is supposed, finally the radiation temperature is obtained. At present, when the method is used to measure the temperature, the spectral emissivity is fixed with the assumption of the mathematical model, and the fixed model is unable to adapt to the target under different temperature conditions. Similarly, at different temperatures, how to calculate the final emissivity and radiation temperature has been no universal method. Based on the Planck’s law of black body radiation, this paper proposes a new idea that is based on the form invariance of the spectral emissivity function under different temperatures. According to the method, the emissivity model adapte to the dynamic change of the object according to the object under different temperature conditions. At the same time, it also puts forward a general method to calculate the final emissivity and radiation temperature. Through a lot of simulations and experiments, it is proved that the method proposed in this paper is more simple and practical than the existing spectral emissivity solution, which can effectively improve the accuracy of the calculation of spectral emissivity,so as to improve the accuracy of the radiation temperature measurement. At the same time, the method proposed in this paper has the characteristics of good practicability and wide application.
2017 Vol. 37 (03): 685-691 [Abstract] ( 211 ) PDF (3025 KB)  ( 115 )
692 Study of a Laser Wavelength Correction Method Applied to the Measurement of OH Radical with Laser-Induced Fluorescence
XING Xing-biao1, HU Ren-zhi1*, XIE Pin-hua1, 2*, CHEN Hao1, LING Liu-yi3, WANG Dan1, WU Jun2, LI Zhi-yan1
DOI: 10.3964/j.issn.1000-0593(2017)03-0692-05
A method for dye laser wavelength correction applied for the measurement of OH radical with FAGE (Fluorescence Assay by Gas Expansion) is researched in this article. Sufficiently stable concentration of OH radical is produced with thermal dissociation of H2O by using an alumel filament and the fluorescence is excited with 282 nm laser in a low pressure cell. The fluorescence is detected with a photomultiplier and a high speed data acquisition card, while the laser light is monitored by a photodiode, and both signals are handled by a LabVIEW program for further analysis. The data acquisition card is triggered by a positive TTL pulse generated by a digital delay generator, which is triggered by a rising edge of a synchronized output pulse of the dye laser. The LabVIEW program is used to determine the location of the OH excited line according to the fluorescence intensity of OH radical when the frequency of the dye laser is scanned. By scanning dye laser wavelength range in 281.97~282.28 nm, excitation spectrum of OH radical is recorded. In order to optimize system parameters and achieve a high signal-to-noise ratio, the effects of the humidity, oxygen concentration, mass flow and pumping speed on fluorescence intensity and lifetime are studied at Q12 line and less than ±1.9% fluctuations of the fluorescence intensity is obtained. With analysis of the reaction mechanism of the thermal dissociation of H2O, it is concluded that reaction of oxygen and water is a major source of OH radical. Laser output wavelength is scanned in a small range around Q12 line to find out the exact exciting line and then correct the laser’s output, which might slightly shift due to the environmental change and leads to reduction of fluorescence intensity. The wavelength correction procedure is implemented many times and the results show that the systematic error of the instrument is less than 0.1 pm. According to the experimental results, this method meets the needs of quantitative accurate measuring tropospheric OH radical by FAGE.
2017 Vol. 37 (03): 692-696 [Abstract] ( 170 ) PDF (2916 KB)  ( 69 )
697 Experimental and Theoretical Study on Terahertz Spectra for Regenerated Cellulose
DAI Ze-lin, XU Xiang-dong*, GU Yu, ZOU Rui-jiao, HAN Shou-sheng, PENG Yong, LIAN Yu-xiang, WANG Fu, LI Xin-rong, CHEN Zhe-geng, SUN Ming-hui, JIANG Ya-dong
DOI: 10.3964/j.issn.1000-0593(2017)03-0697-07
In this work, regenerated cellulose films were prepared with an iced dissolution method, while the physical morphologies and crystal types of the products were systematically characterized with scanning electron microscope (SEM), Fourier transform infrared(FTIR), while X-Ray Diffraction (XRD). The results demonstrate that the as-prepared continuous and uniform films are indeed cellulose Ⅱ, whose morphology and crystal type are significantly different from those of the degreased cotton. Moreover, Terahertz time domain system (THz-TDS) and FTIR were employed to measure the THz spectra of the regenerated cellulose films. Accordingly, the THz characteristic peaks for the regenerated cellulose films are experimentally identified for the first time. In addition, the increase of the THz transmittance with the decrease of the wavenumber is attributed to the existence of amorphous components in the regenerated cellulose films. Although the shapes of Far-IR spectra in the range of 100~700 cm-1 are similar, the absorption peaks of the regenerated cellulose films move to lower wavenumbers (blue shift) compared with those of the degreased cotton. Based on this, we developed a new approach to distinguish the allomorphism of cellulose Ⅱ and cellulose Iβ by Far-IR. Particularly, geometry optimization and IR calculation for the crystal structure of cellulose Ⅱ have been successfully processed by Density Functional Theory (DFT) using periodic boundary condition via CASTEP package. The calculated absorption peak positions are in good agreement with those experimentally measured. Consequently, the THz characteristic peaks of the regenerated cellulose films have been systematically and successfully assigned. Theoretical calculations reveal that the peaks at 42 and 54 cm-1 are assigned to the lattice vibration modes coupled with translational mode and rotational mode, respectively. Moreover, the absorption peaks in the range of 68~238 cm-1 are related with the torsion vibration of —CH2OH group and deformation vibration of C—H bond and O—H bond, while those in the range of 351~583 cm-1 are assigned to the skeletal vibration of C—O—C bond and pyranoid ring, and those at 611 and 670 cm-1 are originated from the out-of-plane bending vibration of O—H bond. Each absorption peak is involved in more than single vibration mode. The THz spectra presented in this work, together with the theoretical simulations, indicate that the THz responses of regenerated cellulose are closely associated with both its chemical constituents and molecular structure. These results will be helpful not only for better understanding the relations between the molecular structure of the regenerated cellulose and its THz spectrum, but also for providing valuable information for future studies on the physical mechanisms of THz responses of other partially-crystalline polymers and organic biological macromolecules.
2017 Vol. 37 (03): 697-703 [Abstract] ( 186 ) PDF (2143 KB)  ( 129 )
704 Spectral Reflectance Reconstruction with Nonlinear Composite Model of the Metameric Black
WANG Jia-jia1, LIAO Ning-fang1*, WU Wen-min1, CAO Bin1, LI Ya-sheng1, CHENG Hao-bo2
DOI: 10.3964/j.issn.1000-0593(2017)03-0704-06
Metamerism phenomenon is an important problem in spectral reflectance reconstruction and color reproduction. In this paper, a 3-primary color CCD camera is used to acquire spectral information in CIE standard illuminant D65 and a nonlinear composite model is established, including principal component analysis and neural network method (PCA-NET) to modify the Matrix R Method based on the Metameric Black theory. The standard Munsell color card is used in spectral reflectance reconstruction experiment and the results are evaluated and discussed. The experimental results verified that the PCA-NET algorithm can accurately fit the nonlinear relationship between the output signal of the camera and the principal component coefficients; and it can be used in the R matrix algorithm instead of the linear algorithm; the new method can serve as a promising technique for building a spectral image database whihc is better than the original Matrix R Method. In the fixed illumination environment, the mean RMS of the test set is 0.76 improved, and the mean STD of the test set is 0.85 improved, which can effectively improve the accuracy of spectral reflectance reconstruction. The modified matrix R method has the advantages of higher accuracy and easy implementation, and it can be used in the field of color reproduction and spectral reflectance reconstruction.
2017 Vol. 37 (03): 704-709 [Abstract] ( 164 ) PDF (2290 KB)  ( 120 )
710 Study on the Overshoot Effect of Doped PhOLED with Transient Electroluminescence
HONG Xiao-xia1, 2, XU Zheng1, 2*, ZHAO Su-ling1, 2, QIAO Bo1, 2, ZHANG Cheng-wen1, 2, WANG Peng1, 2
DOI: 10.3964/j.issn.1000-0593(2017)03-0710-05
The accumulation carriers and the trapped carriers are found in many organic light-emitting diodes (OLEDs) more or less, which can lead to a great loss of carriers and weaken the performance of devices. We have investigated a host-guest-system containing the green phosphorescent emitter tris[2-phenylpyridinato-C2,N]iridium(Ⅲ) [Ir(ppy)3] and one host material with transient electroluminescence (EL). The charge recombination, accumulation and light emission mechanisms of the phosphorescent organic light-emitting diodes (PhOLEDs) with different host materials were analyzed. The structure was fabricated as ITO/NPB(30 nm)/host: Ir(ppy)3/BCP(10 nm)/Alq3(20 nm)/LiF(0.7 nm)/Al(100 nm),the hosts were CBP, PVK and TAZ respectively. These results showed the transient EL was strongly dependent on host materials. Compared to devices of host material CBP and PVK, only those with the host material TAZ as the emitting layer exhibited strong electroluminescence overshoots between 1 and 3 μs after turning off the voltage pulse at room temperatures. To further elucidate the generality of the overshoots, we monitored their dependence on the dopant concentration. The transient EL results in host-guest-system devices demonstrated a direct link between the strong overshoot effect and charge trapping in the emitting guest molecules. The excessive electrons in the guest sites could be a major factor inducing significant strong overshoot phenomenon in the TAZ: Ir(ppy)3 layer. We attributed these overshoot effect to the electrons accumulated on Ir(ppy)3 sites and accumulated holes in the vicinity of the HBL/EML interface. As a result, we obtained a better understanding of carriers’ dynamics and recombination process of PhOLEDs after turning off the voltage pules. The new understanding of the charge carriers and exciton dynamics of PhOLEDs is instrumental in directing the efforts of developing stable and high-efficiency PhOLEDs.
2017 Vol. 37 (03): 710-714 [Abstract] ( 247 ) PDF (2827 KB)  ( 91 )
715 Study on Tandem Polymer Light Emitting Devices
LEI Yong, LIU Zhen, FAN Chang-jun, JI Xia-xia, PENG Xue-feng, LI Guo-qing, YANG Xiao-hui*
DOI: 10.3964/j.issn.1000-0593(2017)03-0715-08
We report tandem polymer light emitting devices by using the PEDOT∶PSS/ZnO/PEIE charge generation layer (CGL) and investigate the influences of the conductance and thickness of PEDOT∶PSS layer on the properties of the devices. The results indicate that the conductance and thickness of PEDOT∶PSS layer have marginal impact on the J-V characteristics of the devices, while significant influences of device efficiency upon utilization of different PEDOT∶PSS specimens mainly come from their different strengths on exciton quenching. Luminance efficiency of TOLEDs with the PEDOT∶PSS thickness of 60 nm in CGL is better than TOLEDs with the PEDOT∶PSS thickness of 30 nm in CGL, the reason is that PEDOT∶PSS thickness of 60 nm the surface topography is more even . Luminance efficiency and driving voltage of the tandem devices match the sum of the luminance efficiency and driving voltage of the component light-emitting units, respectively, indicating that charges generated in the CGL can be injected efficiently into the adjacent light-emitting units. Incorporation of a V2O5 layer into the CGL structure only slightly affects the J-V and LE-I characteristics of the tandem devices, suggesting that the utilization of the PEDOT∶PSS/ZnO/PEIE CGL enables the simplification of the CGL structure without compromising device performance. The luminescence spectra of TOLEDs obviously involves two light emitting unit of spectrum, which shows that two light emitting unit in TOLEDs is normal work. Measurements on the capacitance-voltage characteristics of the CGL-based devices confirm that under negative bias (ITO anode) charges are accumulated and displaced in the CGL, which is totally in line with the full operation of light emitting units in the tandem devices. PEDOT∶PSS/ZnO/PEIE layer is evidenced the effective CGL. On this basis, for the first time we report tandem polymer light emitting devices containing three SY-PPV light-emitting units,which show the mixture of luminance efficiency and external quantum efficiency of 21.7 cd·A-1 and 6.95%, similar to the total luminance efficiency and external quantum efficiency of constituent LEUs. At 5 000 cd·m-2, the luminance efficiency and external quantum efficiency of the tandem devices are 20.5 cd·A-1 and 6.6%. Thus, the increase in the number of light emitting units leads to almost no performance losses, implying the robustness of the PEDOT∶PSS/ZnO/PEIE CGL. Tandem polymer light emitting devices containing three SY-PPV light-emitting units of the luminescent spectra is close to the light emitting unit. Further efforts on the optimization of hole injection layer in the CGL to minimize exciton quenching are underlying to promote the luminance efficiency of tandem polymer light emitting devices.
2017 Vol. 37 (03): 715-722 [Abstract] ( 140 ) PDF (4170 KB)  ( 123 )
723 Preparation and Study on the Spectral Properties of SrBPO5∶Dy3+ Phosphor
YANG Yong1,2, HAN Yue1, GUAN Li2*, WANG Hao-yan2, LI Xu2*, TENG Feng2
DOI: 10.3964/j.issn.1000-0593(2017)03-0723-05
A series of SrBPO5∶Dy3+ phosphor used for UV excited white LEDs were synthesized with high temperature solid state method. The XRD patterns and luminescent properties were investigated. The results indicated that the sample was single SrBPO5 phase. The emission spectrum included two emission peaks locating at 485 and 575 nm excited by 388 nm UV light. The influence of Dy3+ ions concentration, Mg2+ ions dosage, sintering temperature and charge compensator on the luminescent properties was studied. The emission intensity reaches the maximum when the concentration of Dy3+ ions is 4 mol%; the ratio of B/Y increases with the amount of Mg2+ ions and Na+ is the optimal charge compensation. The results showed that this phosphor has a stronger yellow peak, which can raise the yellow emission and enhance the ability of penetrating haze of UV based high transmission white LED.
2017 Vol. 37 (03): 723-727 [Abstract] ( 166 ) PDF (2767 KB)  ( 78 )
728 The Preparation and Properties Study of High CRI White LED Based on Remote Phosphor Technology
LI Bo-chao1, 2, ZHUO Ning-ze2*, LI Wen-quan2,3, HE Qing-yang1, 2, HUANG Ru-xi2, LIU Guang-xi2, YE En-gan1, 2, WANG Hai-bo2*
DOI: 10.3964/j.issn.1000-0593(2017)03-0728-05
Focusing on the defects in the lighting color of LED lamps and the chip heat exists in the traditional LED package which caused phosphor performance degradation, color temperature drift and the uneven light, the remote phosphor package which is emerging in recent years is used in this paper. With yellow-green YGG phosphor and nitrogen red phosphors mixing with silica gel, the remote phosphor is made and then encapsulated as the LED lamps. A lot of experiments were made to determine the best ratio of yellow green phosphor, red phosphor and silica gel, LED lamps with different color temperature was prepared. The lamps were also tested and analyzed with some parameters such as e color coordinates, luminous efficiency, color rendering index (CRI), R9, color quality scale (CQS), color temperature, and the gamut area index (GAI), which provide a more objective and comprehensive evaluation to the high quality LED lighting. Experimental results show that the optimum ratio of red and yellow-green phosphor is 1∶7.6, and total phosphor with silica gel is 1∶5,at this time the white LED lighting color temperature is 4 113 K, the color coordinate (x, y) is (0.375 4, 0.373 1), luminous efficiency is 52.33 lm·w-1, color gamut is 0.981, color rendering index is up to 96, R9 is 97, color quality scale Qa is up to 93, and the gamut area index is 79. Compared with the traditional packaging,the surface temperature ofthe remote phosphor encapsulated fluorescent plate is much lower than that of adhesive dispensing encapsulation, which can effectively avoid the harmful effect caused by high temperature on the LED.
2017 Vol. 37 (03): 728-732 [Abstract] ( 197 ) PDF (2843 KB)  ( 168 )
733 Analysis of Characteristic Parameters of the Surface Fourier Transform Infrared Spectra from Normal Human Breast
WU Min, CUI Long, WANG Gang, LING Xiao-feng, ZHAO Hong-mei, XU Zhi*
DOI: 10.3964/j.issn.1000-0593(2017)03-0733-04
A total of two hundred cases of surface Fourier transform infrared (FTIR) spectra from normal female breast were obtained by scanning two hundred enrolled healthy volunteers’ upper limit of the right breast outside the skin with two mid-infrared optical fibers and an attenuated total reflectance (ATR) probe. Twelve characteristic bands of the above FTIR spectra, related to deoxyribonucleic acid, ribonucleic acid, proteins, lipids and carbohydrate were analyzed. Thirty-six spectral parameters of these characteristic bands, including peak positions (P), intensities (I) and full width at half maximum (F) of FTIR spectrums, were statistically analyzed. Meantime, 90% normal reference value range, mean value, standard deviation of above characteristic parameters was obtained and calculated. In present study, we had establish the normal reference range of spectral parameters of characteristic bands in the surface Fourier transform infrared spectra scanned from normal female breast, for the first time. Meanwhile, for further implementation of Fourier transform infrared spectroscopy technique in noninvasive, fast and efficient characteristic clinical diagnosis of breast benign and malignant diseases, these research results was of great importance. Eventually, this study also had made an attempt to explore the profound theoretical basis in the biomedical application of Fourier transform infrared spectroscopy technique.
2017 Vol. 37 (03): 733-736 [Abstract] ( 141 ) PDF (839 KB)  ( 133 )
737 Influence Analysis of Target Surface Emissivity on Infrared Radiation Polarization Characteristics
CHEN Wei-li1, SUN Qiu-ju2, WANG Shu-hua1, LI Jun-wei1, DONG Yan-bing1, XU Wen-bin1
DOI: 10.3964/j.issn.1000-0593(2017)03-0737-06
Polarization imaging contains rich target parameters including spectrum, radiant intensity, polarization state, space geometry, etc. Polarization imaging can improve the target detection and recognition ability. The infrared polarization imaging is a new infrared detect technology in recent years. Infrared polarization imaging mainly aims to detect and identify the target with the difference of infrared radiation polarization characteristic between target and scene. But the state of polarization is affected by transmission medium in the transmission process of infrared radiation polarization information while the common method is to analyze the infrared radiation polarization characteristics of target that is not able to describe effects of all interrelated parameters and is difficult to estimate influence factors in the process of transmission. The equation of infrared polarized radiation is established through bidirectional reflectance distribution function based on micro-facet theory. And the mathematical model of the relationship between infrared radiation polarization degree and emissivity is derived in this paper. Result shows that the influence of target surface emissivity on the infrared degree can be ignored. On the basis of theoretical analysis, the infrared spectrum polarization imaging tests are unfolded, and the analysis of test data is consistent with the theoretical analysis. It is concluded that the correlation between the polarization degree of infrared and the emissivity of target surface can be neglected. The research production of this paper is conductive to increase of target detect efficiency, and it will provide new ways and means for camouflage target detect and identify. Therefore, the research production can be applied to detect and identify the camouflage target that is accomplished camouflage through change emissivity of camouflage target surface.
2017 Vol. 37 (03): 737-742 [Abstract] ( 141 ) PDF (3268 KB)  ( 472 )
743 Effect Soft Measurement Model of Steel Slag Powder Repair Heavy Metal Contaminated Soil with Fourier Transform Infrared Spectrum
YANG Gang1,2, LI Hui1, CHENG Dong-bo2, XU De-long1, CHEN Hua1, GU Heng-xing1
DOI: 10.3964/j.issn.1000-0593(2017)03-0743-06
Using converter slag as curing stabilizing agents, applying Toxicity Characteristic Leaching Procedure (TCLP) and Fourier transform infrared spectroscopy method of tracking and detection of heavy metals in soil remediation effect of slag powder, and the micro-structure of mixtures (slag powder and heavy metal contaminated soils). It can establish soft sensor mode which is based on Gaussian process regression slag powder on heavy metal contaminated soil remediation effect. by using Gaussian process regression. The results show that the steel slag powder on heavy metals contaminated soil has good repairing effect, 180 d within its restorative effects are maintained over 90%; the repair process is divided into early, middle and late stages, in which the early (1~3 d) repair mode is given priority to with ion exchange high alkaline environment, medium-term (7~42 d) ion exchange and gel setting weaken the enhanced role of the late (56~180 d) form a large number CSH gel, the gel solidification further strengthened; based on Gaussian process regression Steel slag powder on heavy metal contaminated soil remediation effect soft measurement model of the real and predicted values agree well with the data, the absolute error is -1.35 ~-0.48, relative error of -1.448%~-0.497%.
2017 Vol. 37 (03): 743-748 [Abstract] ( 206 ) PDF (1619 KB)  ( 105 )
749 Study on Recognition of Cooking Oil Fume by Fourier Transform Infrared Spectroscopy Based on Artificial Neural Network
YE Shu-bin1,2, XU Liang1*, LI Ya-kai1, LIU Jian-guo1, LIU Wen-qing1
DOI: 10.3964/j.issn.1000-0593(2017)03-0749-06
With the developing of catering trade, cooking oil fume has became one of the three major air pollution sources in some cities. In recent years, a lot of research on the cooking oil fume have been done for its high threaten to human health. The cooking oil fume contains a large amount of unsaturated hydrocarbons produced by pyrolysis of edible oil, which are harmful to human health. The characteristics of the composition and content of edible oil fumes produced by pyrolysis of different edible oil are different. For classification and identification of edible oil, two kinds of classification and identification mathematical model are constructed. The spectrum data of different edible oil fume are collected by Fourier transform infrared spectrometer which is independent research and development. At the same time, different classification algorithms of the principal component analysis (PCA) combining probabilistic neural network (PNN) and the error back propagation artificial neural network (BPANN) are constructed respectively. Two kinds of classification algorithms are used to analyze the Fourier transform infrared spectrum data of different cooking fume gas. The mathematical models are trained by the sample data, and the trained mathematical model are used to analyze the unknown spectral data to determine the type of edible oil. The experimental results show that the two algorithms can classify and identify different types of oil fume. In the whole band recognition, the recognition rate is 90.25% and 97% respectively. By analyzed spectral data of flue gas absorption band, spectrums of atmospheric window and the strong absorption feature bands of volatile organic compounds (VOCs) (from 1 300 to 700 cm-1 and from 3 000 to 2 600 cm-1) were extracted. The absorbance data are divided into two parts with separated absorption band, and the two algorithms in 3 000~2 600 cm-1 band have better recognition rate. PCA-PNN algorithm recognition rate is 90.25% and PCA-BPANN algorithm recognition rate is 92.25%. Obviously, two kinds of artificial neural network algorithm combining principle component analysis respectively can effectively identify the types of edible oil fume.
2017 Vol. 37 (03): 749-754 [Abstract] ( 158 ) PDF (1662 KB)  ( 486 )
755 Rapid Detection of Atrazine at Workplace with Near-Infrared Spectroscopy
ZHOU Xing-fan1, SONG Xiang-zhong2, FU Zhao-hui1, ZHAO Peng1, XU Zhi-zhen1, TANG Shi-chuan1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0755-05
As a wildly used herbicide, Atrazine is mainly produced in China. In order to strengthen the routine detection of Atrazine exposure concentration and protect the health of occupational contact workers, it’s of great importance to develop on-site rapid detection method. A self-assembled near infrared spectrometer was used to record spectra of laboratory prepared atrazine solutions with concentration range from 10 to 1 000 mg·L-1. The influences of different pretreatment methods, such as multiplicative scatter correction, standard normal variate, first order derivative (D1), second order derivative and their combinations, different variable selection methods, such as competitive adaptive reweighted sampling (CARS) and genetic algorithm (GA), different regression methods, such as partial least square (PLS) and support vector regression(nu-SVR), on the model prediction accuracy were investigated. Results show that D1 is the best pretreatment method; GA obtain better results than CARS on selecting highly related spectral variables; nu-SVR model perform better than PLS model. The nu-SVR model constructed with 16 spectral variables selected by GA obtained the best results, whose coefficient of determination for calibration, the coefficient of determination for validation, root mean square error of calibration, root mean square error of validation (RMSEV) and residual validation deviation (defined as SD/RMSEV where SD denotes standard deviation) are 1, 0.99, 17.54 mg·L-1, 25.42 mg·L-1 and 11.43, respectively. These results indicate near infrared spectroscopy combined with chemometrics has great potential to quantify Atrazine concentration at workplace. This research explores the feasibility of quantification Atrazine at workplace with near infrared spectroscopy for the first time, which has great reference value for similar work in the future.
2017 Vol. 37 (03): 755-759 [Abstract] ( 172 ) PDF (1339 KB)  ( 439 )
760 Identification of Transgenic Soybean Varieties Using Mid-Infrared Spectroscopy
FANG Hui1, ZHANG Zhao1, WANG Hai-long1, YANG Xiang-dong2, HE Yong1, BAO Yi-dan1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0760-06
Transgenic technology has enormous significance in increasing food production, protecting biodiversity and reducing the use of chemical pesticides and so on. However, there may be some security risks; therefore, research on genetically modified crop identification technology is attracting more and more attention. Mid-infrared spectroscopy combined with feature extraction methods were used to investigate the feasibility of identifying different kinds of transgenic soybeans in the wavelength range of 3 818~734 cm-1. For this purpose, partial least squares-discriminant analysis (PLS-DA) was employed as pattern recognition methods to classify three non-GMO parent soybeans(HC6, JACK and W82)and their transgenic soybeans. The results of the calibration set were 96.67%, 96.67% and 83.33% for three non-GMO parent soybeans and their transgenic soybeans, and the results of the prediction set were 83.33%, 85% and 85%. X-loading weights, variable importance in the projection (VIP) algorithm and second derivative (2-Der) algorithm were applied to select sensitive wavenumbers. The sensitive wavelengths selected with x-loading weights were used to build PLS-DA model, the classification accuracy of the calibration set were 91.11%, 91.67% and 81.67%, and the results of the prediction set were 80%, 80% and 75%. By using the VIP algorithm, the classification accuracy of the calibration set were 94.44%, 95% and 76.67%, and the results of the prediction set were 80%, 85% and 75%. By using the 2-Der algorithm, the classification accuracy of the calibration set were 88.89%, 81.67% and 80%, and the results of the prediction set were 76.67%, 75% and 75%. Principal components analysis (PCA) and independent component analysis (ICA) were applied to extract feature information. The principal components were combined with PLS-DA model. The classification accuracy of the calibration set were 96.67%, 90% and 80%, and the results of the prediction set were 80%, 90% and 80%. The independent components were combined with PLS-DA model. The classification accuracy of the calibration set were 93.33%, 83.33% and 83.33% while the results of the prediction set were 83.33%, 75% and 75%. The overall results indicated that mid-infrared spectroscopy could accurately identify the varieties of the non-GMO parent soybeans, which provided a new idea for nondestructive testing of transgenic soybeans. Feature extraction methods could be used to build more concise models and reduce the amount of program operations combined with sensitive wavenumbers selection methods.
2017 Vol. 37 (03): 760-765 [Abstract] ( 198 ) PDF (2957 KB)  ( 180 )
766 Density Functional Theory Calculation and Raman Spectroscopy Studies of Carbamate Pesticides
HUANG Shuang-gen1, 2, HU Jian-ping1*, LIU Mu-hua2, WU Rui-mei2, WANG Xiao-bin2
DOI: 10.3964/j.issn.1000-0593(2017)03-0766-06
In order to obtain the molecular structure vibration information of carbamate pesticide, three carbamate pesticides (carbaryl, carbofuran and aldicarb) were optimized and calculated with B3LYP hybrid functional and 6-31G(d,p) basis set, and their experimental spectra were collected with the Raman spectrometer. The theoretically calculated spectra were compared with the experimental spectra carefully. The results indicated that the theoretically calculated spectra have a very good match with the experimental spectra. The vibrational peaks of three carbamate pesticides were assigned between the range of 400~3 200 cm-1, and the characteristic peaks of carbamate pesticide were found at 874, 1 014, 1 162 and 1 716 cm-1. The characteristic peaks of three carbamate pesticides were found by the contrast of the experimental spectra. The results can provide a theoretical basis for the detection of carbamate pesticide, and will be applied to the identification of carbamate pesticide residues in agricultural products.
2017 Vol. 37 (03): 766-771 [Abstract] ( 141 ) PDF (2126 KB)  ( 136 )
772 The Improved Suppression and Analysis of Stray Light in the Miniature Raman Spectrometer
ZHOU Zhao, CHEN He*, ZHANG Yin-chao, CHEN Si-ying, GUO Pan, MU Tao-tao
DOI: 10.3964/j.issn.1000-0593(2017)03-0772-06
Stray light analysis has great benefits in designing Raman spectrometry system, which is the sensitive detection system of weak optical signal. In this paper, optical design software and Solidworks are utilized to optimize the optical and mechanical structure. The system resolution is 0.7 nm, and the volume is 110 mm×95 mm, which belongs to portable and miniature Raman spectrometer. Based on the stray light simulation model, we made an analysis of ray tracing simulation for this system. First, the stray light come with the incident ray were suppressed by the aperture stop. Then the receiver of stray light was introduced and improved in the design progress to suppress internal stray light, especially for zero-order diffraction light of plane grating. The improved receiver of stray light is more effectively using the internal space of the spectrometer and analysis results show that a 50% reduction in the number of stray light and stray light normalized irradiance intensity from 10-5 down to 10-7. The analysis shows that the improved receiver of stray light can effectively suppress stray light, which is beneficial to weak signal detection, and provide reference for design and adjustment of the miniature Raman spectrometer.
2017 Vol. 37 (03): 772-777 [Abstract] ( 151 ) PDF (4608 KB)  ( 490 )
778 Qualitative and Quantitative Studies on Artemisinin with Raman Spectroscopy
KONG Meng-hong, WU Du-xuan, CHEN Xiang-bai*
DOI: 10.3964/j.issn.1000-0593(2017)03-0778-05
Artemisinin, one of the most powerful new generation antimalarial drugs, is an unique sesquiterpene lactone compound extracted from traditional Chinese drug Artemisa annua L, which contains specific endoperoxide bridge. In this study, the Raman scattering of artemisinin in the spectral range of 100~3 500 cm-1 has been investigated. The analysis suggests that the phonon mode at 724 cm-1 would be directly correlated with a representative vibrational mode of the ring containing endoperoxide bridge, thus it can be applied for Raman detection of endoperoxide bridge in artemisinin. The phonon mode at 1 734 cm-1 would be directly correlated with a representative vibrational mode of the lactone ring, thus can be applied for further identification of artemisinin with Raman spectroscopy. Also both of these two phonon modes can be easily observed by Raman experiment; therefore they are good representative phonon modes for quick qualitative analysis of artemisinin by Raman spectroscopy. In addition, by investigating the relative intensity ratio of the two representative phonon modes at 724 and 1 734 cm-1, the Raman method can be applied for quantitative analysis of artemisinin purity. Compared with the commonly used high performance liquid chromatography method, the Raman method is much more powerful: it is faster, more convenient, more accurate, and can be applied for the analysis of homogeneity of purity for artemisinin samples. Furthermore, the qualitative and quantitative analysis of artemisinin purity would be very helpful for quantitative analysis of the quality of Chinese drug Artemisa annua L with Raman spectroscopy.
2017 Vol. 37 (03): 778-782 [Abstract] ( 171 ) PDF (1417 KB)  ( 523 )
783 Characterizing the Existence of Fluorescence Quenching Agents Using EEM Fluorescence and UV Spectra: Taking the Interaction of Humic Acid and Fe(Ⅲ) as an Example
LI Wei-hua1, 2, WU Gun1, 2, YAO Liang1, 2, HUANG Xian-huai2, WANG Jia-qin1, 2, SHEN Hui-yan1, 2, XUE Tong-zhan1, 2
DOI: 10.3964/j.issn.1000-0593(2017)03-0783-05
The fluorescence quenching agents was characterized with three-dimensional fluorescence and ultraviolet (UV) spectra. When there was Fe (Ⅲ) in the sample, the humic fluorescence would be quenched and their UV spectra were not affected. The variation of fluorescence intensity (I) at Ex/Em=300/510 nm and UV absorbance(A) at UV300 were investigated in the article. The smaller the ratio of fluorescence intensity versus UV absorbance (I/A) is, the higher the fluorescence quencher Fe(Ⅲ) concentration is. According to Stern-Volmer equation I/I0=1-fc×Kc×[c] /(1+Kc×[c] ) and fitted function I/A=[k/(cFe3++c)+b] , the fitted fluorescent quenching constant Kc was ranged between 1.08 to 1.15, the ratio of bounded fluorophores versus total fluorophores, i.e. fc, was ranged between 1.10 to 1.14. The ratio of fluorescence intensity and absorbance of humic acid was fitted with Fe(Ⅲ) concentration and the constants were acquired as following: f=0.83~1.19, k=587.19~612.19, c=0.87~0.92, b=-87.09~-46.36. The correlation curve values were 0.99. The Stern-Volmer formula was used to describe the quenching effect of humic acid fluorescence by Fe (Ⅲ). However, due to the fact that the fluorescence intensity I0 without quencher was difficult to acquire during the analysis of practical samples, the fitted function between the ratio of I/A and Fe(Ⅲ) was used to reflect the quenching effect of Fe(Ⅲ) on the fluorescence of humic acid, which was based on the correlations between the fluorescence intensity I0 and ultraviolet absorbance A. The fitted formula was used to predict the iron ions concentration of the resin separated and concentrated samples from wastewater treatment plant and receiving waters. The predicted values were in good accordance with those determined with inductively coupled plasma atomic emission spectroscopy(ICP-AES) method when the iron ion concentration was above 0.4 mg·L-1, which could be used to ascertain the existence of fluorescence quenching agent and their corresponding concentration.
2017 Vol. 37 (03): 783-787 [Abstract] ( 213 ) PDF (2913 KB)  ( 90 )
788 Study on Three-Dimensional Fluorescence Spectral Characteristics of Heterocyclic Pesticides in Different Environmental Conditions
WU Wen-tao1, CHEN Yu-nan1,2,3, XIAO Xue2,3, YANG Rui-fang2,3, ZHAO Nan-jing2,3*
DOI: 10.3964/j.issn.1000-0593(2017)03-0788-06
The impact analysis of different environments on the fluorescence emission spectrum of pesticides is critical in detecting the concentration of pesticides. In this paper, three kinds of pesticides, carbendazim, carbaryl and fuberidazole, were selected as the research objects. Under different environment, such as different pH values and the presence of different common anion or cation, three-dimensional fluorescence spectral emission (EEM) characteristic of pesticides were analyzed. The experimental results showed that the primary fluorescence peaks for three kinds of pesticides were at λex/λem=280/300, 310/340 and 280/335 nm (respectively); Carbendazim and fuberidazole had a secondary peak at 245/305 nm (PeakB) and 250/340 nm (PeakB). We can come to the conclusion that with the change of pH value, the characteristic of fluorescence emission of carbendazim and fuberidazole is similar. We can find that the fluorescence intensities of carbendazim and fuberidazole were enhanced with the declining of the solution acidity or alkalinity and the fluorescence intensity of carbaryl had not changed with the declining of the solution acidity, but it increased with the declining of the solution alkalinity; the fluorescence emission spectra of the three kinds of pesticides had good fluorescence characteristics with the scope of the pH varying from 6.16 to 7.4. Twelve common ions in water (CO2-3,SO2-4,NO-3,Cl-,HPO2-4,HCO-3,Mg2+,Zn2+,NH+4,Na+,Ca2+,K+) had no significant effect on fluorescence emission characteristics of carbendazim and fuberidazole. The fluorescence intensities were seriously influenced by Fe3+ and Cu2+. The results showed that the pesticides fluorescence intensities were decreased with the ion concentration increasing. It was necessary to consider the quenching effects on pesticides of Fe3+ and Cu2+for the analytic results. The obtained results provided the basic research for improving the accuracy of the heterocyclic pesticides measurement in water.
2017 Vol. 37 (03): 788-793 [Abstract] ( 176 ) PDF (5866 KB)  ( 110 )
794 Research on Detection and Modeling of Chlorothalonil Pesticide Residue in Typical Fruit Juice with Fluorescence Spectrometry
WANG Xiao-yan1,2, CHEN Ren-wen1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0794-05
Fluorescence spectrum of mixed solution between chlorothalonil and typical fruit juice (apple juice and peach juice) were obtained with fluorescence spectrophotometer. It was found that there was a characteristic peak in 352 nm of chlorothalonil. Regression analysis was applied in the modeling of relationship between fluorescence intensity and chlorothalonil concentration. Estimation function of chlorothalonil concentration was deduced through fluorescence spectrum and its derivative fluorescence spectrum. The correlation coefficients of the exponential prediction model under two kinds of spectral patterns were higher than 0.99, which was better than the linear function model. For the two kinds of fruit juice, the average recoveries of the exponential model function under the original spectral pattern were 101% and 100% while the average recoveries of the linear model were 110% and 118%, respectively; The average recoveries of the exponential model function under the derivative spectral mode were 101% and 102%, and the average recoveries of the linear model were 109% and 120% respectively. The analysis results showed that fluorescence spectrometry can be used to detect and predict the chlorothalonil residue in fruit juice, and the performance of established exponential function model was better than the linear function model. At the same time, derivative fluorescence spectrometry method was found to have no significant advantage in the concentration prediction model of chlorothalonil residue in fruit juice, so the original fluorescence spectrum can be directly applied in the modeling analysis.
2017 Vol. 37 (03): 794-798 [Abstract] ( 181 ) PDF (2520 KB)  ( 116 )
799 An Optimized Ultraviolet-Visible Spectrum Dual Optical Path Length Fusion Algorithm for Water Quality Monitoring
WU De-cao1, 2, WEI Biao1*, XIONG Shuang-fei1, FENG Peng1, TANG Ge1, TANG Yuan1, LIU Juan1, CHEN Wei3, QIU Yu2, CHEN Yuan-yuan2, YE Xin4
DOI: 10.3964/j.issn.1000-0593(2017)03-0799-07
In terms of water quality monitoring based on the ultraviolet-visible spectroscopy, different optical path lengths of spectrometer probe need to be set to maintain higher signal-to-noise ratio of the spectra when the water body measured is complex and changeable. However, large numbers of experiments always have to be undertaken to get the appropriate optical path length, which is difficult to meet the demand of real-time, accurate, sensitive and stable online monitoring system. In this paper, an optimized spectra fusion algorithm was developed to improve the signal-to-noise ratio of fused spectra from two independent spectra that were acquired using two different optical path lengths. In the fusion algorithm, the sliding-pane method was applied to obtain the distribution of noise variance of the spectra, so the region of strong noise in the spectra could be determined. Due to different signal intensity of spectra with long and short optical path length, genetic algorithm was used to calculate the optimal gain matching rate of fusion. Finally, according to the distribution of noise variance, piecewise weighted method is applied to achieve a fusion spectrum with higher signal-to-noise ratio. The experimental results showed that the fusion algorithm could effectively enhance the signal-to-noise ratio of the fused spectra for each sample without altering the optical path length; the noise within 200~250 nm was suppressed and the low-noise and high-sensitivity spectra in the visible band were preserved; Zero interference was moved to the left of 220 nm of the spectrum. This means the fusion algorithm not only shows improvements in both signal-to-noise ratio and the detailed characteristics of the spectrum, but also reduces the excessive number of experiments in order to optimize optical path length and minimize noise in spectra. It has important practical significance to broaden the application range of the ultraviolet-visible spectroscopy based water quality monitoring system.
2017 Vol. 37 (03): 799-805 [Abstract] ( 150 ) PDF (4894 KB)  ( 128 )
806 UV-Vis Spectrum Characteristics of Phycocyanin Purification in Water from Chao Lake
ZHANG Fa-yu1, YU Jin-wei1, ZHANG Liu2, SHENG Jing-meng1, YUAN Meng-yuan1, LU Yi-nan1, WANG Jia-quan1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0806-05
Fresh blue algal from Chao Lake was used in this study. The crude extracts of phycocyanin were obtained with freeze-thaw method. The purification of phycocyanin was performed by combining two-step salt precipitation and two-step column chromatography. The reagent grade phycocyanin was achieved. Phycocyanin and impurity solution were obtained respectively in various stages subjected to the UV-Vis absorption spectrum scanning. With the development of the four-step purification process, the absorption peak of phycocyanin solution was redshifted from 260 to 280 nm in the wavelength range from 250 to 300 nm, and the maximum absorption peak of phycocyanin was redshifted from 617 to 620 nm in the wavelength range from 500nm to 700 nm. In the wavelength range from 250 to 700 nm, it showed that the impurity solution mainly contained impurity proteins and part of the phycocyanin in the first salting out, and mainly contained nucleic acids and vitamins substance in the second salting out. The first outflow components mainly contained phycoerythrin separated by the first column chromatography. The last outflow components mainly contained allophycocyanin separated by the second column chromatography. After the four-step purification process, the final purity of phycocyanin (A620/A280) is greater than 4,which met the standard of reagent grade.Thus it can be seen that two-step salt precipitation had a main function which was to remove impurity proteins, nucleic acids and vitamins substance, and two-step column chromatography main function was to remove phycoerythrin and allophycocyanin which were similar to phycocyanin.
2017 Vol. 37 (03): 806-810 [Abstract] ( 176 ) PDF (2391 KB)  ( 445 )
811 High Sensitive and Selective Detection of PFOS with Resonance Light Scattering Technology Based on the Interaction with Victoria Blue B
CHEN Xian-ping1, TAO Yi2, WU Fei1,3, LIANG Jia-man1, ZHANG Fang1, TAN Ke-jun1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0811-05
This report presents a simple, sensitive and selective victoria blue B (VBB)-based resonance light scattering (RLS) assay of perfluorooctane sulfonate (PFOS). In pH 6.0 KH2PO4-NaOH buffer solution, VBB can be protonated and reacts with PFOS through electrostatic interactions to produce ionic-association complexes. Simultaneously, the interaction leads to enhanced resonance light scattering intensities greatly, which are characterized with a peak at 277 nm. It is found that the enhanced RLS intensity is proportional to the concentration of PFOS in a range of 0.05 to 4.0 μmol·L-1. The limit of detection is 5.0 nmol·L-1. While, under the optimal experimental conditions, almost no change of the resonance light scattering intensity was observed between VBB and perfluorooctane acid (PFOA) which is one kind of representative perfluorinated compounds (PFCs). The excellent selectivity of PFOS could be due to the hydrophobicity of PFOS higher than PFOA. It is worth noting that the proposed method is capable of differentiating PFOS and some other PFCs. UV/Vis absorption spectrum and scanning electron microscope (SEM) image both were investigated to further validate the reaction mechanism. The interference of coexisting foreign substances and the optimum tests of reaction conditions, including pH value, reaction time, experimental temperature and ionic strength, were also investigated. This method has been successfully applied to the determination of PFOS in environmental water samples with RSD ≤1.74%. The experimental process as followed: In 2 mL colorimetric tube, 200 μL pH 6.0 KH2PO4-NaOH buffer solution, followed by adding 600 μL 20 μmol·L-1 VBB solution, swirl evenly, then add the right amount of PFOS solution. After vortex mixing with ultrapure water volume to 2 mL, swirl to mix, stand for 10 min at room temperature. Then the mixture was transferred for RLS measurements and absorption measurement.
2017 Vol. 37 (03): 811-815 [Abstract] ( 140 ) PDF (2187 KB)  ( 78 )
816 Study on the Method of Voigt Profiles Two Wings Fitting Non-Uniform Flow Field Absorbance
NIE Wei1, 2, YE Qing-hao3, XU Zhen-yu1, ZHANG Guang-le1, XIA Hui-hui1, 2, KAN Rui-feng1*
DOI: 10.3964/j.issn.1000-0593(2017)03-0816-06
In the field of the absorption spectrum, especially for direct tunable diode laser absorption spectroscopy (dTDLAS) technology, the integrated area of the absorption spectrum is needed to be measured accurately for calculating the temperature and the component concentration of the flow field. Doing single optical path absorption spectroscopic measurement in the non-uniform flow field, spectral lineshape broadening is varied with the flow changes, in previous research reports, researchers mainly use single Voigt or Lorentz profile to fit absorbance curve or use directly integral to obtain the integrated area of the absorption spectrum. There are some shortcomings in these methods, resulting in certain error between the fitting result and the actual area, which is not conducive to the accurate measurement of flow field parameters. Firstly, the error is analyzed theoretically, and then, we adopt the simulation method to obtain the error size of the method. Finally, we proposed the Voigt wings fitting absorbance method to reduce the fitting error. The operation of Voigt wings fitting method is to Select the wings of the spectral line, and then use Voigt profile fitting, The difference between the two wings was used the numerical integral method to calculate area, the integrated area is sum of Voigt profile fitting area and numerical integral area. We have used water vapor as the target gas, with eight absorption lines which have different low-level states energy from HITRAN 2012 database being selected-, building two kinds of non-uniform flow field model base on the flat flame furnace, and through the method of segmentation to equivalent processing the no uniformity of flow field. Using Voigt profile fitting method, numerical integral method and Voigt profile wings fitting method to obtain the integral area of models, the error size is obtained by comparing with the theoretical value. As the result of contrast, the fitting error of Voigt profile fitting method is large and related to the different absorption line, the error of numerical integral method is biggest but it is nothing to do with absorption line, the fitting error of Voigt profile wings fitting method is least and stable. By force of contrast, we determined the appropriate method to obtain integral area in the different non-uniform flow field, which is beneficial to obtain accurate integrated area and flow field parameters.
2017 Vol. 37 (03): 816-821 [Abstract] ( 203 ) PDF (2798 KB)  ( 80 )
822 Study on Color Quantitative Expression, Replication and Color Origin of Gray-Purple Nephrite from Qinghai, China Based on Spectroscopy Methods
LUO Ze-min, SHEN Andy, YANG Ming-xing
DOI: 10.3964/j.issn.1000-0593(2017)03-0822-07
Color is one of the most important factors in evaluating the quality and price of jewelry. Quantitative research on color of jewels has been a hotspot in gemological science. Whether for jewelry industry or gems research, observing and describing the gems’ color characteristics under transmission light is an essential method. This study focuses on building a research method to quantitatively characterize nephrite color, and to determine their color origin based on transmitted spectroscopy techniques. Natural gray-purple nephrite of Sanchahe mining, Qinghai, China was chosen as a typical subject due to its gradual-change color characteristic. We first quantitatively expressed and replicated the different color region on a gray-purple nephrite sample with given thickness (1.0 mm) with UV-Visible absorption spectra and 1976 CIE L*a*b* colorimetric parameters, as well as Adobe Photoshop software. The replicated color of light and dark color regions were both close to the transmitted color observed by naked eyes. It is inferred that the subtle color differences between naked eyes observation and transmitted spectroscopy replication may from the multiple effects of incident light in translucent polycrystalline structure, such as absorption, refraction, diffraction, scattering, and so on. As for the purple color origin, Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS) showed an increase of the concentrations of manganese (Mn) as the nephrite color becomes darker. Moreover, the emission peak at 585 nm on Photoluminescence (PL) and absorption peak at 530 nm on Ultraviolet Visible (UV-Vis), and the sextet Mn2+ resonance peaks on Electronic Paramagnetic Resonance (EPR) provide solid support to prove that Mn2+ should be the main factor contributing to the purple color. This work provides a specific experimental method on quantitative observing and describing the color of gems under transmitted light, and it also offers valuable information on determining the chromophores and color origin.
2017 Vol. 37 (03): 822-828 [Abstract] ( 184 ) PDF (2945 KB)  ( 119 )
829 Review of Research and Application for Vegetation BRDF
ZHANG Xu-zhou, DU Peng-peng, HE Yong, FANG Hui*
DOI: 10.3964/j.issn.1000-0593(2017)03-0829-07
Plant leaves, as a vital organ of the plant photosynthesis, directly reflects the plant growth and nutrition status. Internal physicochemical property model, based on the reflection and transmission of plant leaf, indirectly reflects the information of matter and energy exchange in the process of plant growth information, which can be the premise and foundation of the plant growth process of fine management. The optical properties of plant leaves plays a great significant role in the field of crop nutrition diagnosis and plant morphological structure based on remote sensing, in the field of virtual plant light transmission simulation and computer graphics et al. BRDF (Bidirectional Reflectance Distribution Function) mainly focused on spatial distribution and spectral characteristics of the reflected light on the surface of the object characteristics. It can characterize crop growth parameters accurately and efficiently by acquiring optical properties information of plant leaves, which also has great advantages in the research and application of remote sensing in agriculture. In order to better apply BRDF technology in the agricultural remote sensing, this paper will focus on BRDF measurement and device, model development and classification and its application in the field of plants remote sensing. Eventually, although BRDF technology is still in early exploration stage and is facing many tough challenges, it has a promising future in terms of digital agriculture development.
2017 Vol. 37 (03): 829-835 [Abstract] ( 275 ) PDF (935 KB)  ( 214 )
836 Identification of Varieties of Dried Red Jujubes with Near-Infrared Hyperspectral Imaging
FAN Yang-yang, QIU Zheng-jun*, CHEN Jian, WU Xiang, HE Yong
DOI: 10.3964/j.issn.1000-0593(2017)03-0836-05
In order to realize rapid identification of dried red jujubes, this paper proposes a method based on near-infrared hyperspectral imaging technology. The near-infrared hyperspectral images (1 000~1 600 nm) of 240 samples in total from 4 cultivars of dried red jujubes will be acquired. The samples are to be divided into the calibration set and the prediction set in the ratio of 2∶1. 7, 8, 10 effective wavelengths are to be selected by principal component analysis(PCA), x-loading weight(x-LW)and successive projection algorithm(SPA) respectively. The dimensionality of original hyperspectral images will be reduced with PCA, and texture features of the first principal component image are to be extracted with gray-level co-occurrence matrix(GLCM).The partial least squares-discriminant analysis(PLS-DA), back propagation neural network(BPNN)and least square support vector machine(LS-SVM) are to be applied to build identification models with the selected effective wavelengths, texture features and fusion of the former two features. The identification rates of the models based on fusion features will be higher than those of models based on the spectral features or texture features respectively. The BPNN models based on the fusion features will obtain the best results, whose identification rates of prediction set are to be 100%. The results in this paper indicate that the near-infrared hyperspectral imaging technology has great potential to identify the dried red jujubes rapidly.
2017 Vol. 37 (03): 836-840 [Abstract] ( 198 ) PDF (2564 KB)  ( 210 )
841 Estimation of Soil Water Content Based on Hyperspectral Features and the ANN Model
DIAO Wan-ying, LIU Gang*, HU Ke-lin
DOI: 10.3964/j.issn.1000-0593(2017)03-0841-06
Soil water content (θ) is an important factor for the crop growth and crop production. The objectives of this study were to (i) test various regression models for estimating θ based on spectral feature parameters, and (ii) compare the performance of the proposed models by using artificial neural networks (ANN) and spectral feature parameters. The θ data of sand and loam and concurrent spectral parameters were acquired at the laboratory experiment in 2014. The results showed that: (1) the maximum reflectance with 900~970 nm and the sum reflectance within 900~970 nm estimate θ had the significant, when sand bulk density was 1.40 g·cm-3; the maximum reflectance with blue edge and the sum reflectance within 900~970 nm had the best correlation (R2>0.70) when sand bulk density was 1.50 g·cm-3; while soil bulk density was 1.60 g·cm-3, the sum reflectance within 780~970 nm and normalized absorption depth in 560~760 nm reached a significant (R2>0.90); when soil bulk density was 1.70 g·cm-3, the maximum reflectance with 900~970 nm and the sum reflectance within 900~970 nm had the best correlation estimate θ (R2>0.88). 2) When the soil type was loam, the maximum reflectance with 900~970 nm and the sum reflectance within 900~970 nm had a best correlation estimate θ. The spectral feature parameters the sum reflectance within blue edge (R2=0.26 and RMSE=0.09 m3·m-3) and 780~970 nm absorption depth (R2=0.32 and RMSE=0.10 m3·m-3) were best correlated with θ in the sand. The θ model based on maximum reflectance with 900~970 nm (R2=0.92 and RMSE=0.05 m3·m-3) and the sum reflectance within 900~970 nm had a high correlation (R2=0.92 and RMSE=0.04 m3·m-3) in the loam. The BP-ANN model presented a better estimation accuracy of θ (R2=0.87 and RMSE=0.05 m3·m-3) in two soils. Thus, the ANN model has great potential for estimating θ. Thus, the BP-ANN model has great potential for θ estimation.
2017 Vol. 37 (03): 841-846 [Abstract] ( 166 ) PDF (1834 KB)  ( 252 )
847 Hyperspectral Imaging Detection of Total Viable Count from Vacuum Packing Cooling Mutton Based on GA and CARS Algorithms
DUAN Hong-wei1, ZHU Rong-guang1*, XU Wei-dong1, QIU Yuan-yuan1, YAO Xue-dong1, XU Cheng-jian2
DOI: 10.3964/j.issn.1000-0593(2017)03-0847-06
In the process of spectral modeling, spectral extraction of characteristic bands with different variable screening algorithms is an important step for improving the model effects. Total viable count of cooling mutton under vacuum packing condition was chosen as the research index in this paper, while the influence of 2 variable screening algorithms on its hyperspectral PLS model effects was compared. Mutton muscle spectra of Regions of interest (ROIs) were extracted and preprocessed. Subsequently, Genetic Algorithm (GA) and Competitive Adaptive Reweighted Sampling (CARS) were applied to extract characteristic bands from preprocessed spectra at full band range of 473~1 000 nm. Model effects of GA-PLS, CARS-PLS and W-PLS with corresponding bands selection were contrasted and analyzed. The results indicated that both model effects of GA-PLS, CARS-PLS were better than that of W-PLS, and CARS-PLS model effect was optimal. As for the CARS-PLS model, the determination coefficient (R2c) and root mean square error (RMSEC) of calibration set was 0.96 and 0.29, and the determination coefficient (R2cv) and root mean square error (RMSECV) of leave-one-out cross validation was 0.92 and 0.46, respectively. Meanwhile, the determination coefficient (R2p), root mean square error of prediction (RMSEP) and the ratio of standard deviation to standard error of prediction (RPD) of prediction set was 0.92 and 0.47 and 3.58, respectively. Therefore, hyperspectral imaging (HSI) technology combined with CARS-PLS can achieve quick, non-destructive and accurate detection of mutton total viable count.
2017 Vol. 37 (03): 847-852 [Abstract] ( 174 ) PDF (2351 KB)  ( 85 )
853 Visualization of Protein in Peanut Using Hyperspectral Image with Chemometrics
YU Hong-wei, WANG Qiang, SHI Ai-min, YANG Ying, LIU Li, HU Hui, LIU Hong-zhi*
DOI: 10.3964/j.issn.1000-0593(2017)03-0853-06
The study aims to explore the potential of hyperspectral imaging (HSI) with chemometrics for rapidly and non-invasively visualizing the spatial distribution of protein content which can affect the quality of peanut products as a critical component of peanut. Spectral data contained in the region of interest (ROI) of the corrected hyperspectral images of peanut were extracted and protein contents were measured with conventional chemical method. By comparing different pretreatments and modeling algorithms, the second-order derivatives (2nd-der) on spectra is optimal pretreatment, and partial ceast square (PLS) is the best regression method. Based on the pretreatment spectra and the measured protein content model, a good performance model (RC=0.91, SEC=0.86; RP=0.86, SEP=0.69) was built with full wavelengths. The fourteen optimal wavelengths were carried out based on the regression coefficients (RC) of the established PLS model. Then, using optimal wavelengths built RC-PLS model which show resembling performance (RC=0.86, SEC=1.03; RP=0.80, SEP=0.77). At last, an imaging processing algorithm was developed to transfer each pixel in peanut to protein content with the 2nd-der-RC-PLS model. There was no significant difference between Kjeldahl and HSI method by the paired test. The result demonstrated the capacity of HSI in combination with chemometrics for fast and non- destructively determining protein content in peanut.
2017 Vol. 37 (03): 853-858 [Abstract] ( 171 ) PDF (2146 KB)  ( 213 )
859 A New Vegetation Index Infusing Visible-Infrared Spectral Absorption Feature for Natural Grassland FAPAR Retrieval
LI Zhe1, 2, GUO Xu-dong1*, GU Chun2, ZHAO Jing3
DOI: 10.3964/j.issn.1000-0593(2017)03-0859-06
Considering the close relationship between spectral absorption features of visible-near infrared and “Fraction of Absorbed Photosynthetically Active Radiation(FAPAR)”, the “automatic recognition method of hyperspectral curve’s characteristic absorption peak” and “quantization method of spectral absorption characteristic parameters” were used to extract the hyperspectral absorption characteristic parameters which are sensitive to FAPAR. Referring to mathematical form of vegetation index, visible-near infrared spectral absorption characteristic parameters were used to replace spectral reflectance and create a new vegetation index to estimate FAPAR of vegetation. The data from 2014 and 2015 on typical natural grassland community canopy in the middle and eastern Inner Mongolia was chosen to build and verify the model of estimating FAPAR. The results showed that new vegetation index “SAI-VI” effectively raised the FAPAR estimating accuracy in the middle and low vegetation coverage areas. Compared with other seven different types of visible-near infrared vegetation index, it has a higher correlation with the value of FAPAR(the largest correlation coefficient is 0.801). The FAPAR prediction index model which takes “SAI-VI” as variable has higher precision and better stability(the determination coefficients of modeling and testing are the highest and both are above 0.75, the “Root Mean Square Error (RMSE)” and “Average Error Coefficient (MEC)” are the minimum). The research also showed that the new vegetation index “SAI-VI” infusing visible-infrared spectral absorption feature highlights the difference between visible spectral and near infrared spectral absorption characteristic parameters. While comparing with single spectral absorption characteristic parameter, “SAI-VI” can depress the influence of soil and enhance the sensitivity to the changes of FAPAR. “SAI-VI” also included the information of hyperspectral absorption characteristic parameters which are sensitive to FAPAR and expressed more detailed information of FAPAR while comparing with original spectral reflectance. “SAI-VI” can be used as a new parameter in inversion of vegetation canopy FAPAR, to some extent it could remedy defect of vegetation index method in estimating FAPAR.
2017 Vol. 37 (03): 859-864 [Abstract] ( 175 ) PDF (2396 KB)  ( 80 )
865 The Syntheses and Spectroscopic Properties of the Styryl Quinoline Derivatives
WANG Ming, CHEN Zhen-xing, CHEN Ge-yu, HOU Bao-long, WANG Cui-ling, LIU Jian-li*
DOI: 10.3964/j.issn.1000-0593(2017)03-0865-04
The simple method of the syntheses of the styryl quinoline derivatives was developed. The intermediate of 2-methylquinoline was synthesized from 10 mmol aniline and 20 mmol (E)-2-Butenal dissolved in 8 mL methylbenzene refluxing at 100 ℃ for 3 hours with 10 mL 6 M hydrochloric acid as catalyst. Eight derivatives were obtained in 15 mL glacial acetic acid using 2-methylquinoline (10 mmol) and aromatic aldehyde (12 mmol) as materials refluxing for 8 hours with a yield of 71%~88%. The method is simple, high yield, easy purification and environment friendly. The structures of all derivatives were confirmed with MS, 1HNMR and IR. The vicinal coupling constant of olefinic carbon hydrogen in 1HNMR is 12~18 Hz, and moderate strength absorption peaks appeared at 960~980 cm-1 in IR indicate that carbon-carbon double bond is transconfiguration. Maximum absorption wavelengths of eight products in CH3OH, DMSO, THF and DMF were measured, and emission wavelengths were measured using maximum absorption wavelengths as excitation wavelengths. It turned out that maximum absorption wavelengths among different solvents were 325~376 nm, and emission wavelengths were 367~477 nm. The molar extinction coefficients were within the range of 1.738×104~4.578×104 L·mol-1·cm-1. The maximum absorption wavelengths and emission wavelengths of styryl quinoline derivatives with methoxyl, hydroxyl and benzyl group are greater than others. Among four solvents, the maximum absorption wavelengths almost unchanged, however, the emission wavelengths varies significantly in the following order DMSO>DMF>CH3OH>THF, which indicates the Stokes shift of one product at aprotic solvent is greater than protic solvent. 2-(3,4,5-trimethoxyphenyl)styryl quinolone (Product Ⅱ) which shows the best fluorescence property and the highest Stokes shift value worth further studying.
2017 Vol. 37 (03): 865-868 [Abstract] ( 206 ) PDF (1233 KB)  ( 90 )
869 Research on the Impact of Absorption Feature Extraction on Spectral Difference Between Similar Minerals
ZHAO Heng-qian1, ZHAO Xue-sheng1*, CEN Yi2, YANG Hang2
DOI: 10.3964/j.issn.1000-0593(2017)03-0869-06
Diagnostic absorption features can indicate the existence of specific materials, which is the foundation of mineral analysis with optical remote sensing data. In hyperspectral data processing, the most commonly used method to extract absorption feature, is Continuum Removal (CR). As for multispectral data, Principle Component Analysis and other indirect methods were used to extract absorption information, and little research has been done on full-band absorption feature extraction. Classification of similar minerals is one of the major difficulties in mineral spectral analysis, while there is no valid index for spectral difference between similar mineral groups. Absorption feature extraction may improve the classification accuracy, but there is no research to investigate the impact of absorption feature extraction on spectral difference between similar minerals. This paper summarized the principle of mineral spectral difference, and proposed the concept of Class Separability Ratio (CSR), which was verified to be a valid index for spectral difference between similar mineral categories. Through comparison experiments on alunite and kaolinite spectra, including USGS spectral library spectra and resampled spectra in accordance with the band settings of HYPERION, ASTER and OLI, the impact of absorption feature extraction on spectral difference between similar minerals were investigated. Experimental results show that valid absorption feature extraction can greatly enhance the spectral difference between similar minerals, and the spectral difference is positively correlated with spectral resolution. Besides, the results of CR can be severely affected by spectral resolution and band center positions, and the absorption feature spectra extraction results for multispectral datasets need to be improved. This research laid the foundation of precise identification between similar mineral categories, and provided valuable reference for the band settings of future geology remote sensing sensors.
2017 Vol. 37 (03): 869-874 [Abstract] ( 161 ) PDF (3323 KB)  ( 516 )
875 Preparation and Photocatalytic Activity of CeO2 Loaded Porous Alkali-Activated Steel Slag-Based Catalyst
KANG Le, ZHANG Yao-jun*, ZHANG Li, ZHANG Ke, YANG Meng-yang
DOI: 10.3964/j.issn.1000-0593(2017)03-0875-06
High value-added utilization of solid wastes is one of the important ways of sustainable development. A novel pore size-controlled alkali-activated steel slag-based cementitious material (PASSCM) was synthesized by adjusting the content of pore forming agent of acrylic resin emulsion. Meanwhiel, a new type of porous steel slag-based catalyst loaded CeO2 was prepared via incipient wetness impregnation method in the paper. The composition, structure and optical properties of photocatalysts were characterized with XRF, XRD, BET and UV-Vis DRS. Meanwhile, the photocatalytic performance of hydrogen production from water was evaluated. The results showed that adding pore-forming agent changed the pore structure and the mesoporous volume increased by 70.27% of alkali-activated steel slag-based cementitious material. The mesoporous volume increased by 144.14% in photocatalyst loaded 8 Wt% CeO2. In the simulated solar source irradiation for 6 h, the photocatalyst loaded 8wt%CeO2 exhibiting the highest photocatalytic hydrogen production activity (7 653 μmol·g-1) and hydrogen generation rate [1 275.5 μmol·(g·h)-1], which were attributed to mesoporous volume increases the mass transfer rate of the water molecules, and in the formation of the coupled semiconductors, the high dispersion of the CeO2 active component and the FeO in the carrier promoted the high efficiency separation of the photogenerated electron-hole pairs.
2017 Vol. 37 (03): 875-880 [Abstract] ( 173 ) PDF (3465 KB)  ( 108 )
881 Preparation of Rubber Accelerator Tetrabenzylthiuramdisulfide and Its Spectral Analysis
JIA Tai-xuan1, ZHANG Nan1*, GUO Yao1, LU You-chang1, TIAN Da-yong1, LI Hong-liang2
DOI: 10.3964/j.issn.1000-0593(2017)03-0881-03
In the study, rubber accelerator tetrabenzylthiuramdisulfide (TBzDT) was synthesized with two-step method with hydrogen peroxide as oxidant firstly. TBzDT was detected and characterized with XRD, FT-IR, TG-DTA. Its micro-structure was revealed. Chemical bond types into TBzDT molecule were revealed with FT-IR. TBzDT phase composition and structure were given by crystallographic data from XRD detecting such as cell parameters, crystal face index. The phase composition and qualitative identification of TBzDT structure were completed. Two kinds of information were detected with TG-DTA as to quality change and thermal effect. TBzDT phase transition and decomposition temperature were 142.5, 200.9 ℃ respectively. The decomposition temperature of TBzDT was relevtively high. It could provided reference with research on rubber vulcanizing properties by TBzDT on rubber vulcanizing machine. A little SC2 contained into TBzDT was revealed by FTIR, TG-DTA from different sides.
2017 Vol. 37 (03): 881-883 [Abstract] ( 191 ) PDF (1162 KB)  ( 446 )
884 Study on Detection Sensitivity of Heavy Metal in Water Based on LIBS Combined with Electrode Enrichment Method
WANG Yuan-yuan, ZHAO Nan-jing*, MA Ming-jun, FANG Li, YU Yang, MENG De-shuo, GU Yan-hong, JIA Yao, LIU Jian-guo, LIU Wen-qing
DOI: 10.3964/j.issn.1000-0593(2017)03-0884-05
In order to improve the detection sensitivity of laser-induced breakdown spectroscopy (LIBS) and lower the limit of the detection of elements, LIBS combined with Aluminum electrode enrichment method is adopted to analyze heavy metals such as Pb,Cdand Ni in the water. The relationship between the characteristic spectral intensity and the key parameters-voltage of electrode method is discussed, the spectral intensity increases first and then decreases with the increase of voltage. The spectral intensity reaches the maximum value when the enrichment voltage is 1.2 V while the optimal enrichment voltage value is 1.2 V. The stability of characteristic spectral lines of heavy metals is studied, and the relative standard deviation(RSD) of spectral intensity of Pb, Cd and Ni is 5.98%,4.25 % and 5.27% respectively, the result shows that the spectral line obtained by this method has high stability. A series of samples in the range of 0~0.13 mg·L-1 are prepared and quantitatively analyzed, the limit of detection of Pb, Cd and Ni is obtained 1.2,3.1 and 1.7 ppb respectively. The above result shows that LIBS combined with aluminum electrode enrichment method can effectively improve the stability of characteristic spectral lines and lower the limit of detection of Pb,Cd and Ni. This research also provides a method to further improve detection sensitivity of LIBS and analysis ability of heavy metal in the water.
2017 Vol. 37 (03): 884-888 [Abstract] ( 206 ) PDF (2252 KB)  ( 126 )
889 Emission Spectrometry for the Detection of Methane Based on Gas Ionization Discharge Microplasma at Room Temperature
SHEN Li-hua1*, WANG Hong-ni1,CHEN Pei-jing1, YU Chun-xia1, DENG Hao-nan1,ZHANG Cheng-xiao2
DOI: 10.3964/j.issn.1000-0593(2017)03-0889-07
A microplasma-generating device was developed by using needle-plate electrode discharge with the incorporation a Pt/carbon nanotube (CNT) nanocomposite-decorated FTO electrode. When an alternating current voltage of 1.32 kV and a low power consumption of 13 W in nitrogen (N2) carrier gas are applied, the system can be applied to detect methane at room temperature. The main characteristic lines were assigned to CH, C2 and Hα during the discharge process of CH4 at room temperature.The emission intensity of C2 at 516 nm is linear with the concentration of CH4 from 0.5% to 4.0% (φ), and the detection limit (S/N=3) is 0.19% (φ). The emission intensity of Hα at 656 nm is linear with the concentration of CH4 from 0.1% to 3.0%(φ)with the detection limit (S/N=3) is 0.03% (φ). The relative standard deviation (RSD) is less than 2% from 11 repetitive analyses using 3.2% CH4. The Pt/CNT nanocomposite-modified FTO electrode exhibited enhanced sensing performance with precise, repeatability and linear correlation compared with that of the pure MWNT/FTO electrode and bare FTO electrode. When CH4 were discharged in air, the emission spectra of CH4 was different from that in N2. It was found that C2 peak was disappeared and the Hα intensity was also liner to the concentration of CH4 in the range of 0.5%~4%. The established system exhibited advantages with small size, simple fabrication and operation at room temperature compared to other detection system.
2017 Vol. 37 (03): 889-895 [Abstract] ( 141 ) PDF (3758 KB)  ( 88 )
896 Study on Emission Spectrum of Radicals in Remediation System of Polluted Soil with Pulsed Discharge Plasma in Oxygen
ZHOU Guang-shun1, WANG Hui-juan1, 2*,WU Qiang-shun1, GUO He1
DOI: 10.3964/j.issn.1000-0593(2017)03-0896-06
Based on the advantage of spectroscopy method and the significant effect of ·OH and ·O in advanced oxidation degradation system, the change of relative emission spectra intensities of the ·OH and the ·O in a pulsed discharge plasma (PDP) system bubbled with oxygen were tested by using the spectrum detecting technique in this research. The PDP system with needle-to-net electrode was set up in the paper to remediate the polluted soil. The relative emission spectra intensities of the ·OH and the ·O formed in the PDP system with oxygen (O2) bubbling were detected with the spectrograph to illustrate the critical effect of the ·OH and the ·O on the organic compound degradation in the PDP system. The changes of the relative emission spectra intensities of the ·OH and the ·O under the conditions of without soil addition, with the original soil addition, with the organic compound polluted soil addition and with the organic compound-heavy metal polluted soil addition were firstly investigated in the paper. The effect of peak pulse voltage, electrode gap and O2 flow rate on the relative emission spectra intensities of the ·OH and the ·O were also studied to explain the changing rule of the active species in the PDP system. The obtained results show that the addition of soil are beneficial to the formation of the ·OH and the ·O in PDP system for the soil remediation. The relative emission spectra intensities of the ·OH and the ·O in the PDP system with organic compounds polluted soil addition were lower than those in the PDP system with the original soil addition, which proved the oxidation of the ·OH and the ·O on the organic compounds degradation in the remediation system, and the addition of heavy metal ions were favorable to the degradation of the organic compounds in the PDP system. Furthermore, the increase of the peak pulse voltage as well as theO2 flow rate was in favor of the formation of the ·OH and the ·O, while the relative emission spectra intensities of the ·OH and the ·O were lower under the condition of the higher electrode gap, which demonstrated that the higher electrode gap were not in favor of the active species formation. In the study, based on the description of the pivotal role of ·OH and the ·O in the PDP system for the polluted soil remediation, the influence rule of the main factors during the process of polluted soil remediation in the PDP system on the content of ·OH and the ·O were analyzed. This research will provide some basic experimental evidence for the application of PDP technology on the polluted soil remediation.
2017 Vol. 37 (03): 896-901 [Abstract] ( 138 ) PDF (3294 KB)  ( 63 )
902 Study on Adsorption and Desorption Characteristics of Cd2+ and Cu2+ on the Surface Sediments of Sanhuhekou of Yellow River by Using ICP-MS
ZUO Hang1,3, CHEN Yi-zhen1, CHEN Jian-hua1, GUO Yang1, WANG Ru-ming1, FANG Fang1, ZHAO Jia-ying1, LIU Ying1,2*
DOI: 10.3964/j.issn.1000-0593(2017)03-0902-08
In order to study the interaction mechanism between Cd2+, Cu2+ and surface sediments in the upper reaches of the Yellow River, the surface sediment of Sanhuhekou (YRSSM) was chosen as research object with inductively coupled plasma mass spectrometry (ICP-MS) as analysis method. The adsorption reaction condition such as liquid-solid ratio, reaction time and pH were optimized, and the adsorption and desorption characteristics of Cd2+ and Cu2+ onto the surface sediments under the optimized experimental conditions were studied. The results showed that the adsorption capacity of Cu2+ was greater than that of Cd2+, the equilibrium absorption capacity were 0.88 and 0.13 mg·g-1 under each optimum experimental condition, respectively. The adsorptions of Cu2+ and Cd2+ were in accord with the pseudo-second-order kinetic, while adsorption rate of Cu2+ was also greater than that of Cd2+. The adsorption thermodynamics data were in accordance with the Freundlich model and the fitting. Results showed that the adsorption process of Cu2+ and Cd2+ belonged to the preferential adsorption, and were endothermic and spontaneous processes. The desorption process showed that the Elovich equation were suitable for Cd2+ and Cu2+ and belonged to the heterogeneous diffusion. Multi-ions competitive adsorption and desorption experiments indicated that Cu2+ was influenced more by co-existing ion. The study revealed not only the mechanism of adsorption and desorption between Cd2+, Cu2+ and surface sediment in Sanhuhekou, but also the influence of coexisting ions on the adsorption and desorption characteristics. The results demonstrated that the distribution mechanism of heavy metals between solid-liquid phases, and provided a theoretical basis for the migration ability of heavy metals. It also had a guiding significance for establishing heavy metals preventive and control measures of the study area.
2017 Vol. 37 (03): 902-909 [Abstract] ( 161 ) PDF (4634 KB)  ( 77 )
910 Simultaneous Determination of Impurity Elements in N-Methyl-2- Pyrrolidone (NMP) with Direct Injection Inductively Coupled Plasma Optical Emission Spectrometry
NIE Xi-du1, FU Liang2*
DOI: 10.3964/j.issn.1000-0593(2017)03-0910-04
An analytical method for simultaneous determination of 12 impurity elements including Mo, Cr, Zn, Pb, Ni, Mn, Fe, Cu, Ca, Al, Na and K in N-methyl-2-pyrrolidone (NMP) was established with inductively coupled plasma optical emission spectrometry (ICP-OES). The NMP without decomposing was acidized with nitric acid and analyzed directly, avoiding the risk of error introducing during sample pretreatment. The load of plasma on organic solvent was decreased by optimizing the plasma parameters and ensuring the stability of plasma. The optimized and adopted nebulizer gas flow rate was 0.4 L·min-1 and RF power was 800W. The whole signals during the sample atomization or ionization have been obtained with axially viewed ICP-OES which increases the sensitivity and decrease the detection limits. The interferences of spectral lines and background were eliminated by selecting analysis spectral lines, removing the carbon by adding oxygen and background correction method. Furthermore, standard addition method was employed to overcome the matrix effect, counteracting the ionization interference of high concerned organic matrix to easily ionizable elements. The results showed that the correlation coefficients of the calibration curve were in the range of 0.999 5~1.000 0, the detection limits were in the range of 3.8~106.4 ng·g-1, and the recoveries were in the range of 92.0%~108.0%. The relative standard deviation (RSD, n=11) were larger than 4.8% of the analytes. The method is simple without complex sample pretreatment. It is a fast analysis method with high accuracy which can satisfy completely the requirements of control analysis in mass production. This method can be applied to determine impurity elements in NMP products.
2017 Vol. 37 (03): 910-913 [Abstract] ( 212 ) PDF (964 KB)  ( 76 )
914 Comparative Study on Three Pretreatment Methods for Atomic Absorptive Spectrophotometry Determination of Metal Elements in Lycium Barbarum
WANG Yi-min1*, ZHANG Li-li1, ZHANG Xiao-wen1, ZHANG Ke1, MA Jian-hua1, ZHANG Li1, ZHANG Bao-lin2, SU Li1, WANG Jun-ling1
DOI: 10.3964/j.issn.1000-0593(2017)03-0914-05
A simple, fast and accurate method was explored to determine the mineralelements in Lycium barbaru.Three different pretreatment methods, including dry ashing method, HNO3-H2O2 and HNO3-HClO4 wet digestion, method were employed for digestion of the samples of Lycium barbaru. The concentrations of Na,K,Ca,Mg,Fe,Cu,Zn,Ni,Pb and Cd were determined by using atomic absorption spectrometry. The experimental results showed that the recovery rates of dry ashing method, HNO3-H2O2 and HNO3-HClO4 wet digestion method were in the ranges from 89.88% to 102.15%, 92.34% to 103.21% and 94.52% to 102.10% respectively; the relative standard deviation (RSD) of dry ashing method, HNO3-H2O2 and HNO3-HClO4 wet digestion method were lower than 3.037%, 2.751% and 2.496% separately. The RSD and recovery of three pretreatment methods were all satisfied with the analysis requirements. But compared with dry ashing method and HNO3-H2O2 wet digestion method, the recovery of HNO3-HClO4 wet digestion method was better, and the precision was higher. Besides, compared with three pretreatment methods, the average value of Na, K, Ca, Fe and Cd had statistical difference (p<0.05), and HNO3-HClO4 wet digestion method was significantly higher than others.In addition, HNO3-HClO4 wet digestion method taken a shorter time and less consumption of reagents. Therefore, HNO3-HClO4 wet digestion method can be used as the preferably pretreatment method for the determination of the contents of metal elements by atomic absorption spectrophotometry method.
2017 Vol. 37 (03): 914-918 [Abstract] ( 151 ) PDF (806 KB)  ( 519 )
919 The Research on Matrix Effect and Correction Technology of Rock Sample in In-Situ Energy Dispersive X-Ray Fluorescence Analysis
CHENG Feng1, 2, GU Yi1, 2*, GE Liang-quan1, 2, ZHAO Jian-kun1, LI Meng-ting1, ZHANG Ning1
DOI: 10.3964/j.issn.1000-0593(2017)03-0919-05
The mineral constituents of the rock sample can be analyzed with in-situ energy dispersive X-ray fluorescence analysis technology (In-situ EDXRF), the matrix effect of rock sample will effects on measurement results. The Monte Carlo simulation method is used to conduct fluorescence analysis spectrum with ideal measurement conditions, which provides analytical data for matrix effect research. The measured spectrum of seventeen kinds rock samples are being simulated, which has the same Cu content. Therefore, the influences with matrix effect of rock sample in in-situ EDXRF take Cu element for example. Based on correlation between Cu X-ray intensity and spectral parameters, considering elements similarity of all kinds rock samples, it is found that the variation the Cu X-ray intensity not only by the control of rock elements composition or rock classification. The matrix effect of rock samples must be classified according correlation between Cu X-ray intensity and spectral parameters. After the matrix effect classification, fifteen kinds of rock samples, which belong to the same matrix effect, can be corrected more effective. Based on principal component analysis of similar matrix effect rock samples, it is found that the scattering background, target element K-series X-ray of X-ray tube and its incoherent scatter intensity can be a good description of Cu X-ray intensity which is affected by rock matrix, thus it can be used to correct the Cu element measurement results. Certainly, this technology can also provide reference for matrix effect correction to other elements in rock.
2017 Vol. 37 (03): 919-923 [Abstract] ( 171 ) PDF (2305 KB)  ( 445 )
924 The Study of the Rescale Method of the Spectrum Shifting in X-Ray Fluorescence Well Logging
ZHANG Qing-xian1, ZHAO Jian-kun1, GU Yi1, GE Liang-quan1*, ZHANG Xiao-yue2, ZHANG Jian1, WANG Hai-dong1, ZHANG Le1
DOI: 10.3964/j.issn.1000-0593(2017)03-0924-05
The X-ray fluorescence well logging technology is a significant method that can make quantitative analysis orsemi-quantitative analysis on the wellface. This method is very important to mineral exploration. The spectrum shifting is often observed in the X-rayfluorescence well logging because the temperature in the well changes acutely. The hardware is used to release the spectrum shifting and the software method is used to rescale the tiny spectrum shifting. There are too manyspectra to be rescaled in a well logging task by manually. In this paper, an auto method to rescale spectrum shifting, via the expert system model which is based on the special process to rescale spectrum shifting in manual, is presented. The symmetric zero-area conversion method, which is not sensitive to the changes of the baseline, is used to research the peaks. And then, the characteristic peaks will be identified by the standard errors, automatically. The prior knowledge (the last energy scale) and the gauss probability density function are used to analyze the peaks qualitatively and confirm the energy of characteristic peaks. Then the least square method is applied energy calibration. The singular deviation point, away from the calibrationline, will be rejected and the energy ratio will be obtained again. This method is applied for rescaling spectrum shifting in 322 spectra and obtains a satisfactory achievement.
2017 Vol. 37 (03): 924-928 [Abstract] ( 130 ) PDF (2508 KB)  ( 129 )
929 Study on Smelting Remains of Tangjiadun Site
WEI Guo-feng1, GAO Shun-li1, QIN Ying2*, WANG Le-qun3
DOI: 10.3964/j.issn.1000-0593(2017)03-0929-04
The furnace walls and slags from Tangjiadun site in Zongyang County of Anhui Province were analyzed by means of X-ray fluorescence spectrometer (XRF), X-ray diffraction analyzer (XRD), scanning electron microscope (SEM) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in order to probe into the copper smelting technology of Tangjiadun site. Results show that the furnace walls are from the copper smelting furnaces and the slags are the reduced slag. According to the concentrations of elements As, Ag, Sb and Bi in copper prills, it can be calculated that relative probabilities that these copper prills in the slags come from the copper sulfide ore reach over 87. 87%. Combined with the results of SEM-EDS, the smelting process of “copper sulphide ore-copper” was used in Tangjiadun site, and the smelting remains (slags and prills) were considered as the smelting products of sulphide copper ore. This study is not only beneficial to research on bronze cultural of Zongyang County, but also has very important significance to explore the development and evolution of bronze metallurgy technology in Zongyang-Lujiang area.
2017 Vol. 37 (03): 929-932 [Abstract] ( 127 ) PDF (1687 KB)  ( 420 )
933 The Research of Flatfielding Correction Method for Spatial Heterodyne Spectrometer at Systematic Level
SHI Hai-liang1, 2, LI Zhi-wei1, 2, LUO Hai-yan1, 2, XIONG Wei1, 2
DOI: 10.3964/j.issn.1000-0593(2017)03-0933-06
It can’t satisfy the requirement of correction for response non-uniformity at systematic levelif only if the array detector for spatial heterodyne spectrometer is corrected. Traditional methods, such as irradiation with uniform source and column-flat-fielding, are not suitable for spatial heterodyne spectrometer. The article expounds convection arm-blocking method for spatial heterodyne spectrometer briefly at first. This method leads to kinds of mismatches including pixel and sub-pixel level shift and rotation in a single arm data after gluing gratings. The effect of registration accuracy of flatfielding coefficients has been analyzed for the experimental breadboard. The result shows that the registration accuracy of flatfielding coefficients needs to be better than 0.1 pixel for the breadboard. The shift at pixel level is calculated by solving the rotational degree by using logarithm-polar coordinate and phase correlation method for the requirement of registration. The shift at sub-pixel level is estimated with DFT based on matrix multiplication. The flow path of flatfielding method at systematic level is concluded. The integral condition of interferometer after actual gluing is modulated by adjusting the positions of gratings slightly. The flatfielding flow path is applied to the data acquired from the modulated interferometer after gluing. Then, the result is compared with the spectrum after the correction with totally matched signal arm data. The final result shows that the spectral deviation is 0.6% between the two spectra compared with the spectral deviation of 4.1% without correction. The accuracy of recovered spectrum after correction has been improved markedly. This can be the foundation for the follow data processing.
2017 Vol. 37 (03): 933-938 [Abstract] ( 126 ) PDF (3111 KB)  ( 81 )
939 Comparative Study of Data Compression Methods for Large Aperture Static Imaging Spectrometer
YU Lu1, 2, 3, LIU Xue-bin1*, LI Hong-bo1, 3, LIU Gui-zhong2
DOI: 10.3964/j.issn.1000-0593(2017)03-0939-07
Facing the problem of choosing different data source as compressing object results in different compression effect, several techniques are investigated to explore a better data source which can reduce the loss of image and spectral information while getting higher compression ratio in the compression work of the large aperture static imaging spectrometer. In this paper the optical path difference dimension data source of LASIS was proposed after analyzing the characteristic of LASIS and then compared with the LASIS and LAMIS data source in detail. The SWIR data collected with the principle prototype of LASIS were used in our experiment. Firstly, three forms of data sources were extracted after detailedly introducing their data characteristic and extracting methods. Secondly, the mature algorithms in engineering JPEG and JPEG2000 were employed to compress and reconstruct the three forms of data sources respectively. Finally, the compression effect was evaluated in the aspect of image content, interference dimension, spectral dimension and compression ratio respectively, and the original spectral curves of three materials choosing from the field of view and those after reconstruction were extracted next, then the loss of spectral information of these three materials were measured by using the SA (Spectral Angle) and RQE (Relative Quadratic Error) values of the spectral curves to evaluate the compression effect. It is demonstrated that using the optical path difference dimension data as compressing object shows obvious advantages compared with LASIS and LAMIS, which achieves a combination of higher compression ratio, lower mean square error, lower peak signal noise ratio and less information loss that is competitive with the best results from the literature. The results show that the proposed optical path difference dimension data source has good performance in preserving the spatial and spectral information during the compression of LASIS than the other two common forms data sources of LASIS.
2017 Vol. 37 (03): 939-945 [Abstract] ( 120 ) PDF (4854 KB)  ( 80 )
946 Research on Straightness Error Compensation of Grating Ruling Machine
HUANG Yuan-shen1, 2, DONG Cheng-cheng1, 2*, HUANG Yun-bai1, 2, SHENG Bin1, 2, ZHOU Hong-yan1, 2, SUN Le1, 2, YANG Hai-ma1, 2, ZHANG Da-wei1, 2
DOI: 10.3964/j.issn.1000-0593(2017)03-0946-06
Echelle grating is a kind of special diffraction grating. Working with high diffraction orders and big diffraction angle, which has the advantages of high resolution and full wave shining. It has been widely used in high-end spectrum instrument, which greatly promoted the development of aerospace, astronomy, medical, military, environment and other cutting-edge technology. However, professional scoring system needs to be customized, and the price is very expensive. The use of sophisticated ultra precision machining equipment to process in the ladder grating can greatly reduce the preparation cost of the mother plate of the ladder grating. Due to the bad straightness and high accumulative error of ultra precision single point diamond lathe, it can’t satisfy the demand of preparation when preparing the echelle grating, casuing the bad diffraction wave front. In order to reduce the straightness error, this paper comes up with the error compensation for the single point diamond lathe. Firstly, we make the first compensation based on the accumulative error curve. When the compensation ratio is 0.75 to 0.85, the peak valley value (pv) of the diffraction wave front is about 400 nm, reaching its greatest effect of the first straightness compensation. Secondly, we make the straightness compensation according to the diffraction wave front curve of the blazed order. The pv of the diffraction wave front is about 83nm. The results show that the diffraction wave front is greatly improved which is beneficial to improve the quality of the grating, and has a guiding role in the actual grating characterization.
2017 Vol. 37 (03): 946-951 [Abstract] ( 152 ) PDF (3622 KB)  ( 77 )
952 The Research of On-Orbit Calibration Method Based on Solar Diffuser
HUANG Wen-xin1, 2, ZHANG Li-ming1, 2, SI Xiao-long1, 2, CAO Xing-jia1, 2, LI Jun-lin1, 2, WANG Wei1, 2, ZHU Xue-mei1, 2
DOI: 10.3964/j.issn.1000-0593(2017)03-0952-06
As one of the most important ways of improving the calibration accuracy at present, the calibration method based on a solar diffuser(SD) is an independent calibration way with advantages of high accuracy, high frequency and high efficiency . The principles, methods and implementation process of on-orbit calibration based on the SD is described in this thesis. The radiance reference for calibration in space is found and the physical model of the on-orbit reflectance calibration is provided. The main factor which affects the calibration uncertainty is the determination of the SD bidirectional reflectance distribution function (BRDF) value by analyzing the physical models of on-orbit calibration. Thus, the timing selection of the on-orbit calibration is introduced and the BRDF in the range of angles variety within the calibration timing is tested in the lab. During the on-orbit calibration time, the high accuracy on-orbit calibration in the remote sensors’ whole life is achieved by the accurate radiance input which is ensured by monitoring and correcting the SD BRDF value from its fabrication to its life end. Finally, the on-orbit calibration uncertainty is estimated based on the measurement levels of the parameters in the physical model. And the uncertainties of on-orbit reflectance calibration and method of radiance calibration are better than 2.03% and 2.04% by type B standard uncertainty evaluation method.
2017 Vol. 37 (03): 952-957 [Abstract] ( 179 ) PDF (1776 KB)  ( 92 )
958 Doppler Lidar with High Sensitivity and Large Dynamic Range for Atmospheric Wind Measurement
WANG Li, TAN Lin-qiu, CHANG Bo, LU Geng-geng, GAO Fei, HUA Deng-xin*
DOI: 10.3964/j.issn.1000-0593(2017)03-0958-06
Doppler wind Lidar is an important method for atmospheric wind measurement. The Doppler frequency shift of backscattering spectrum due to the wind is detected from the transmissions of frequency discrimination. High sensitivity and large dynamic range measurement is difficult for atmospheric wind measurement because of the limitationof frequency discriminator characteristic. In this paper, a frequency discriminator constructed with Dual fiber Mach-Zehnder interferometer is proposed. Two fiber Mach-Zehnder interferometers with different atmospheric wind detection dynamic range and sensitivity are designed and used to measure Doppler frequency shift at the same time. The optical path difference of FMZI-2 is 13.7 cm which can realize large dynamic range wind measurement (±100 m·s-1) and the optical path difference of FMZI-1is designed to be 74.8 cm which can realize high sensitivity detection. Moreover, the absolute wind velocity of FMZI-1 channel can be corrected by the measurement result of FMZI-2 channel. Thus the high sensitivity and large dynamic range wind detection can be realized. The sensitivity, SNR and wind error of two channels are simulated and analyzed for different parameters. The results indicate that the system can realize the wind error less than 1 m·s-1 for large dynamic range(±100 m·s-1) wind velocity, which is a beneficial exploration for high sensitivity and large dynamic range Doppler wind lidar.
2017 Vol. 37 (03): 958-963 [Abstract] ( 201 ) PDF (4169 KB)  ( 447 )
964 Study on Hydrogen Fluoride at High Temperature Detection Method with Temperature Correction Based on Laser Technology
HE Ying1,2, ZHANG Yu-jun1, YOU Kun1, GAO Yan-wei1, CHEN Chen1, LIU Wen-qing1
DOI: 10.3964/j.issn.1000-0593(2017)03-0964-07
Hydrogen fluoride(HF) is one of the important character gases for fault diagnosis of gas insulation switch (GIS) in the system of substation equipment. The high-accuracy, fast- response and real-time detection method of HF is a focus in industrial and environmental fields. In this research, the HF detection experiment system was set up at first based on laser absorption spectroscopy technology combined with anti-corrosion multiple reflection cell made by monel steel. Moreover, the laser absorption spectral characteristics of HF at different temperature were analyzed, then the coefficient partition function curve and absorption linestrength curve according to the distribution function coefficient in HITRAN database were studied. As the most important work, the concentration inversion algorithm was designed here with HF character spectrum analysis and temperature parameter correction method for accurate concentration inversion after the basic study. At last, the continuous experimental results were obtained by HF sample gases of different concentration considerating the temperature characteristic of the multiple reflection cell. When the multiple reflection cell was heat and stay stably, the biggest detection error of concentration inversion was 5.33% and 5.87% at 313 and 323 K respectively without temperature correction, and that was 1.20% and 1.47% respectively after temperature correction. By continuous detection and culculation, the detection limit is 8.7×10-5 mmol·mol-1 at 323 K which is a little higher than 6.3×10-5 mmol·mol-1 at 290 K(20 m optical length). Although the detection error with temperature correction at high temperature was higher than it at room temperature, the results show that it was lower than that without correction at the same temperature. It was verified that the this spectrum detection method and concentration inversion algorithm works stably and reliably, so this technology could realize HF real-time monitoring demand in chemical production field and it will provide the effective technical support in gas emission regulation in safety and environment protection for our country.
2017 Vol. 37 (03): 964-970 [Abstract] ( 209 ) PDF (3719 KB)  ( 79 )
971 Solution Cathode Glow Discharge Based on Charge Coupled Device Detector
LIU Xiao, YANG Xiao-tao, ZHAN Xiu-chun*, YUAN Ji-hai, FAN Xing-tao, JIAO Ju
DOI: 10.3964/j.issn.1000-0593(2017)03-0971-07
In 21st century, many countries pay much attention to lithium because lithium is an ideal material for green energy and light alloys as well as an important kind of strategic resources. The main source of lithium is from salt lake brine. China has rich resources of salt lake brine, but these brine resources are mainly distributed in the remote western region, which are in urgent need of portable analytical instrument for on-site exploration and exploitation. However, the available experimental techniques at present can not achieve the target of on-site analysis. Over the past decade, based on atmospheric pressure solution cathode glow discharge-atomic emission spectrometry (SCGD-AES) has been paid attention to analytical researchers because it runs without common air conditions such as fuel gas, carrier gas and vacuum environment. On the basis of previous studies of other researchers, we have developed a portable SCGD based on a charge coupled device (CCD) detector by ourselves, which is short for Li-K analyzer. The length, width, height and weight of the portable Li-K analyzer is 35 cm, 19 cm, 27 cm and 10 kg, respectively, which is very conducive to carry. This work selected the wavelength of 670.78 nm as the characteristic spectral line of Li and has established a rapid analytical method for Li in salt lake brine based on two different types of brines from Tibet. Under the optimum operating conditions, the detection limit of Li was 4 ng·mL-1 and the measured precision (RSD) was better than 2%. The analytical results of Li were much different from those obtained by inductively coupled plasma-mass spectrometry (ICP-MS) with different dilution ratios by standard curve method, which may be related to the matrix effect of solution. However, the analytical results of Li agreed well with the results obtained by ICP-MS using standard addition method, which showed that standard addition method can effectively reduce the matrix effect and improve the analytical accuracies. A great deal of experimental results showed that standard addition method could obtain accurate results of Li using only two points and can greatly reduce the workloads. This work laid a methodological foundation for on-site determination of Li in salt lake brine by the portable Li-K analyzer.
2017 Vol. 37 (03): 971-977 [Abstract] ( 155 ) PDF (1375 KB)  ( 78 )
978 Identification of Coalmine Water Inrush Source with PCA-BP Model Based on Laser-Induced Fluorescence Technology
WANG Ya1,2, ZHOU Meng-ran1*, YAN Peng-cheng1, HE Chen-yang1, LIU Dong1
DOI: 10.3964/j.issn.1000-0593(2017)03-0978-06
The water inrush should been rapidly and accurately identified during preventing coalmine water inrush. The laser induced fluorescent (LIF) spectrum technology provides a new method to identify water inrush with the characteristics of high sensitivity, quick and accurate monitoring. In order to identify water inrush, this paper introduces the spectrum technology of LIF to obtain water inrush fluorescence spectra data. The spectral preprocessing methods of Savitzky-Golay(SG) and Multiplicative Scatter Correction (MSC) have been used to eliminate noise spectra in collecting process. Principal component analysis (PCA) extracts feature information, for SG reprocessing data, when the number of principal component is 3, the cumulative contribution rate can reach 99.76 percent. This method has largely retained the information of original data. This paper chooses the classification model with 3 layers BP neural network, constructing by different training and testing sets. The classification model with SG preprocessing has achieved accurate identification, however, appeared few false identification for MSC and original data. The result shows that SG preprocessing is better than MSC. Research results show that the classification model with PCA and BP neural network can effectively identify coalmine water inrush, and have the strong self-organizing, self-learning ability.
2017 Vol. 37 (03): 978-983 [Abstract] ( 165 ) PDF (3454 KB)  ( 72 )
984 Study on Determination of Molybdenum in Molybdenum Concentrate by Atomic Absorption Spectrometry Indirectly
QU Wei, ZHOU Cheng-ying, CAI Liu-lu, LI Wen-juan
DOI: 10.3964/j.issn.1000-0593(2017)03-0984-06
For the determination of molybdenum in molybdenum concentrate,lead molybdate gravimetric method was considered as standard method. In order to ensure the lead ions to be washed thoroughly from the entrained precipitate, lead molybdate precipitate was washed, filtered repeatedly, then ashed and burned. This method cannot satisfy the rapid measurement demand of mineral processing and metallurgy scientific research due to its time consuming. In the present work, molybdenum was determined by atomic absorption spectrometry indirectly and a rapid analysis method for molybdenum in molybdenum concentrate was proposed. The sample was dissolved by nitric acid, potassium chlorate and sulfuric acid, pH was adjusted by acetic acid and ammonium acetate buffer solution to pH 5~7, then a certain amount and excess of lead standard was added. Based on lead molybdate was considered as undissolved electrolyte on room temperature, the solubility of lead molybdate was 1.16×10-5g, far less than 0.01 g, was considered as the undissolved electrolyte, the electrolyte insoluble at a certain temperature can complete precipitation, usually compared with the solubility production product Qc and the relative size of constant Ksp, when Qc>Ksp, solution was supersaturated, precipitation was precipitate completely, the content of molybdenum in molybdenum concentrate was 40%~60%, the amount of lead was 0.125 0~0.150 0 g, took the minimum calculated solution lead molybdate ion product, Qc=[Pb2+][MoO2-4]=2.51×10-5Ksp=1.0×10-13QcKsp,Therefore lead molybdate precipitate can be precipitated completely, after dry filtered, the excess of lead ions were determined by atomic absorption spectrometry, the content of molybdenum was calculated by subtraction method. In this paper, the amount of acetic acid-ammonium acetate buffer solution, the amount of lead standard, time of lead molybdate precipitation, heating time and maximum amount of coexisting ions such as W6+, Sn4+, Cu2+, etc were investigated. Compared with lead molybdate gravimetric method, repeatedly washing, ashing and burning with lead molybdate were eliminated by proposed method, which was simple, easy to master and was able to cut the analysis time in half. The control experiments were conducted by lead molybdate gravimetric method and proposed method. After the results were implemented by mathematical statistics, it can be concluded that it had good accuracy and precision for the proposed method, which can be applied to rapid analysis of molybdenum in molybdenum concentrate for mineral processing and metallurgy.
2017 Vol. 37 (03): 984-989 [Abstract] ( 172 ) PDF (1264 KB)  ( 114 )
       
990 Application of Joint Skewness Algorithm to Select Optimal Wavelengths of Hyperspectral Image for Maize Seed Classification
YANG Sai, ZHU Qi-bing*, HUANG Min
DOI: 10.3964/j.issn.1000-0593(2017)03-0990-07
As an effective method for the nondestructive measurement of agricultural products quality, hyperspectral imaging technology has been widely studied in the field of seed classification and identification. Feature extraction and optimal wavelength selection are the two critical issues affecting the application of hyperspectral image in the field of seed identification. This study aimed to select optimal wavelengths from hyperspectral image data using joint skewness algorithm, so that they can be deployed in multispectral imaging-based inspection system for the automatic classification of maize seed. The hyperspectral images covering the wavelength range of 438~1 000 nm were acquired for 960 maize seeds including 10 varieties. After extracting the mean spectrum and entropy from the hyperspectral images, the joint skewness algorithm was used to select optimal wavelengths, and the classification models based on support vector machine were developed using the mean spectrum, entropy, and their combination, respectively. The experimental results indicated that the classification accuracy of the models developed by combination of the mean spectrum and entropy were higher than that of the mean spectrum or entropy for either full wavelengths or optimal wavelengths. The classification model for the combination of the mean spectrum and entropy based on the 10 optimal wavelengths selected by the joint skewness algorithm obtained 96.28% accuracy for test samples, with improvements of 4.30% and 20.38% over that of the mean spectrum and entropy, respectively, which was higher than the classification accuracy of the model that developed in the full wavelength (i.e., 93.47%). Meanwhile, the classification model based on joint skewness algorithm yielded the better classification accuracy than that of uninformative viable elimination algorithm, successive projections algorithm, and competitive adaptive reweighed sampling algorithm. This study made the online application of the hyperspectral image technology available for seed identification.
2017 Vol. 37 (03): 990-996 [Abstract] ( 171 ) PDF (2929 KB)  ( 116 )