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2016 Vol. 36, No. 02
Published: 2016-02-01

 
       光谱学与光谱分析
305 The Measuring Method of Atomic Polarization of Alkali Metal Vapor Based on Optical Rotation and the Analysis of the Influence Factors
SHANG Hui-ning, QUAN Wei*, CHEN Yao, LI Yang, LI Hong
DOI: 10.3964/j.issn.1000-0593(2016)02-0305-05
High sensitivity measurements of inertia and magnetic field could be achieved by utilizing a category of devices, which manipulate the atomic spins in the spin-exchange-relaxation-free regime. The alkali cell which contains the alkali metal vapor is used to sense magnetic field and inertia. The atomic number density of alkali vapor and the polarization of alkali metal vapor are two of the most important parameters of the cell. They play an important role in the research on atomic spins in the spin-exchange-relaxation-free regime. Besides, optical polarization plays an important role in quantum computing and atomic physics. We propose a measurement of alkali vapor polarization and alkali number density by detecting the optical rotation in one system. This method simplifies existing experimental equipment and processes. A constant bias magnetic field is applied and the Faraday rotation angle is detected by a bunch of the probe beam to deduce alkali-metal density. Then the magnetic field is closed and a bunch of the pump laser is utilized to polarize alkali-metal. Again, the probe beam is utilized to obtain the polarization of alkali metal. The alkali density obtained at first is used to deduce the polarization. This paper applies a numerical method to analyze the Faraday rotation and the polarization rotation. According to the numerical method, the optimal wavelength for the experiment is given. Finally, the fluctuation of magnetic field and wavelength on signal analysis are analyzed.
2016 Vol. 36 (02): 305-309 [Abstract] ( 393 ) PDF (2574 KB)  ( 243 )
310 Atmospheric Influences Analysis on the Satellite Passive Microwave Remote Sensing
QIU Yu-bao1, SHI Li-juan2, 4, SHI Jian-cheng2, ZHAO Shao-jie3
DOI: 10.3964/j.issn.1000-0593(2016)02-0310-06
Passive microwave remote sensing offers its all-weather work capabilities, but atmospheric influences on satellite microwave brightness temperature were different under different atmospheric conditions and environments. In order to clarify atmospheric influences on Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), atmospheric radiation were simulated based on AMSR-E configuration under clear sky and cloudy conditions, by using radiative transfer model and atmospheric conditions data. Results showed that atmospheric water vapor was the major factor for atmospheric radiation under clear sky condition. Atmospheric transmittances were almost above 0.98 at AMSR-E’s low frequencies (<18.7 GHz) and the microwave brightness temperature changes caused by atmosphere can be ignored in clear sky condition. Atmospheric transmittances at 36.5 and 89 GHz were 0.896 and 0.756 respectively. The effects of atmospheric water vapor needed to be corrected when using microwave high-frequency channels to inverse land surface parameters in clear sky condition. But under cloud cover or cloudy conditions, cloud liquid water was the key factor to cause atmospheric radiation. When sky was covered by typical stratus cloud, atmospheric transmittances at 10.7, 18.7 and 36.5 GHz were 0.942, 0.828 and 0.605 respectively. Comparing with the clear sky condition, the down-welling atmospheric radiation caused by cloud liquid water increased up to 75.365 K at 36.5 GHz. It showed that the atmospheric correction under different clouds covered condition was the primary work to improve the accuracy of land surface parameters inversion of passive microwave remote sensing. The results also provided the basis for microwave atmospheric correction algorithm development. Finally, the atmospheric sounding data was utilized to calculate the atmospheric transmittance of Hailaer Region, Inner Mongolia province, in July 2013. The results indicated that atmospheric transmittances were close to 1 at C-band and X-band. 89 GHz was greatly influenced by water vapor and its atmospheric transmittance was not more than 0.7. Atmospheric transmittances in Hailaer Region had a relatively stable value in summer, but had about 0.1 fluctuations with the local water vapor changes.
2016 Vol. 36 (02): 310-315 [Abstract] ( 394 ) PDF (4033 KB)  ( 172 )
316 Identification of Official Rhubarb Samples by Using PLS and Terahertz Time-Domain Spectroscopy
WANG Jing-rong1, ZHANG Zhuo-yong1*, ZHANG Zhen-wei2, XIANG Yu-hong1
DOI: 10.3964/j.issn.1000-0593(2016)02-0316-06
The development of terahertz technology is attracting broad intention in recent years. The quality identification is important for the quality control of Chinese medicine production. In the present work, terahertz time-domain spectroscopy (THz-TDS) combined with partial least squares (PLS) were used for the identification model building and studied based on 41 official and unofficial rhubarb samples. First, the THz-TDS spectra of rhubarb samples were collected and were preprocessed by using chemometrics methods rather than transformed to absorption spectra. The identification models were then established based on the processed terahertz time domain spectra. The spectral preprocessing methods include Savitzky-Golay (S-G) first derivative, detrending, standard normal transformation (SNV), autoscaling, and mean centering. The identification accuracy of 90% was accomplished by using proper pretreatment methods, which was higher than the classified accuracy of 80% without any preprocessing for the time domain spectra. The component number of the PLS model was evaluated by leave-one-out cross-validation (LOOCV). The minimum values of the root-mean squared error of cross-validation (RMSECV) and root-mean squared error of prediction (RMSEP) were 0.076 6 and 0.169 0 by using mean centering method, respectively. The results of this work showed that the combination of terahertz time domain spectroscopy technology with chemometrics methods, as well as PLS can be applied for the recognition of genuine and counterfeit Chinese herbal medicines, as well as official and unofficial rhubarbs. The advantage of using terahertz time domain spectra directly with no transformation into absorption spectra is: (1) the thickness of samples could not be considered in the model establishment, and (2) the spectral processing was simplified. The proposed method based on the combination of THz-TDS and chemometrics proved to be rapid, simple, non-pollution and solvent free, which is suitable to be developed as a promising tool for quality control of many other Chinese herbal medicines.
2016 Vol. 36 (02): 316-321 [Abstract] ( 406 ) PDF (1437 KB)  ( 187 )
322 The Detection of Ultra-Broadband Terahertz Spectroscopy of InP Wafer by Using Coherent Heterodyne Time-Domain Spectrometer
ZHANG Liang-liang1, ZHANG Rui2, XU Xiao-yan1, ZHANG Cun-lin1
DOI: 10.3964/j.issn.1000-0593(2016)02-0322-04
Indium Phosphide (InP) has attracted great physical interest because of its unique characteristics and is indispensable to both optical and electronic devices. However, the optical property of InP in the terahertz range (0.110 THz) has not yet been fully characterized and systematically studied. The former researches about the properties of InP concentrated on the terahertz frequency between 0.1 and 4 THz. The terahertz optical properties of the InP in the range of 4~10 THz are still missing. It is fairly necessary to fully understand its properties in the entire terahertz range, which results in a better utilization as efficient terahertz devices. In this paper, we study the optical properties of undoped (100) InP wafer in the ultra-broad terahertz frequency range (0.5~18 THz) by using air-biased-coherent-detection (ABCD) system, enabling the coherent detection of terahertz wave in gases, which leads to a significant improvement on the dynamic range and sensitivity of the system. The advantage of this method is broad frequency bandwidth from 0.2 up to 18 THz which is only mainly limited by laser pulse duration since it uses ionized air as terahertz emitter and detector instead of using an electric optical crystal or photoconductive antenna. The terahertz pulse passing through the InP wafer is delayed regarding to the reference pulse and has much lower amplitude. In addition, the frequency spectrum amplitude of the terahertz sample signal drops to the noise floor level from 6.7 to 12.1 THz. At the same time InP wafer is opaque at the frequencies spanning from 6.7 to 12.1 THz. In the frequency regions of 0.8~6.7 and 12.1~18 THz it has relativemy low absorption coefficient. Meanwhile, the refractive index increases monotonously in the 0.8~6.7 THz region and 12.1~18 THz region. These findings will contribute to the design of InP based on nonlinear terahertz devices.
2016 Vol. 36 (02): 322-325 [Abstract] ( 438 ) PDF (1751 KB)  ( 210 )
326 The Influence of Deposition Pressure on the Properties of Hydrogenated Amorphous Silicon Thin Films
YUAN Jun-bao1, YANG Wen1, CHEN Xiao-bo1, 2, YANG Pei-zhi1*, SONG Zhao-ning3
DOI: 10.3964/j.issn.1000-0593(2016)02-0326-05
Hydrogenated amorphous silicon (a-Si∶H) thin films on soda-lime glass substrates were deposited by plasma enhanced chemical vapor deposition (PECVD) using disilane and hydrogen as source gases. To study the influence of deposition pressure on the deposition rate, optical band gap and structure factor, a surface profilometer, an ultraviolet-visible spectrometer, a Fourier transform infrared (FTIR) spectrometer and a scanning electron microscopy (SEM) were used to characterize the deposited thin films. It is found that the deposition rate firstly increased and then decreased and the optical band gap monotonically decreased with the increasing deposition pressure. Moreover, the formation of SiH bond was preferable to the formation of SH2 or SiH3 bond when the deposition pressure was less than 210 Pa, while it was opposite when the deposition pressure is higher than 210 Pa. Finally, the deposition pressure in the range of 110~210 Pa was found to be more suitable for the preparation of high quality a-Si∶H thin films.
2016 Vol. 36 (02): 326-330 [Abstract] ( 380 ) PDF (2070 KB)  ( 201 )
331 Study on the Effects of Alq3∶CsF Composite Cathode Buffer Layer on the Performances of CuPc/C60 Solar Cells
ZHAO Huan-bin, SUN Qin-jun*, ZHOU Miao, GAO Li-yan, HAO Yu-ying*, SHI Fang
DOI: 10.3964/j.issn.1000-0593(2016)02-0331-05
This paper introduces the methods improving the performance and stability of copper-phthalocyanine(CuPc)/ fullerene(C60) small molecule solar cells by using tris-(8-hydroxyquinoline)aluminum(Alq3): cesium fluoride(CsF) composite cathode buffer layer. The device with Alq3∶CsF composite cathode buffer layer with a 4 wt.% CsF at a thickness of 5 nm exhibits a power conversion efficiency (PCE) of up to 0.76%, which is an improvement of 49%, compared to a device with single Alq3 cathode buffer layer and half-lifetime of the cell in air at ambient circumstance without any encapsulation is almost 9.8 hours, 6 times higher than that of without buffer layer, so the stability is maintained. The main reason of the device performance improvement is that doping of CsF can adjust the interface energy alignment, optimize the electronic transmission characteristics of Alq3 and improve the short circuit current and the fill factor of the device using ultraviolet-visible absorption, external quantum efficiency and single-electron devices. Placed composite cathode buffer layer devices with different time in the air, by comparing and analyzing current voltage curve, Alq3∶CsF can maintain a good stability as Alq3. Alq3∶CsF layer can block the diffusion of oxygen and moisture so completely as to improve the lifetime of the device.
2016 Vol. 36 (02): 331-335 [Abstract] ( 340 ) PDF (2376 KB)  ( 143 )
336 Preparation and Performances of the M′-Type LuTaO4∶Eu3+ Transparent Scintillator Films
QIU Zhi-che, GU Mu*, LIU Xiao-lin, LIU Bo, HUANG Shi-ming, NI Chen
DOI: 10.3964/j.issn.1000-0593(2016)02-0336-04
X-ray imaging has a very important role in life sciences and material microstructure analysis and other applications. One of the core components of X-ray imaging equipment is the X-rays-visible light conversion screen. Flashing transparent film is an effective way to achieve high spatial resolution X-ray imaging. M′-type LuTaO4∶Eu3+is an excellent scintillation material. It has high light yield, high density, good radiation hardness and good chemical stability. Therefore, to research and develop the transparent conversion screen with M′-type LuTaO4∶Eu3+ is very important for the application of X-ray detector in high spatial resolution X-ray imaging. In this paper, the M′-type LuTaO4∶Eu3+ transparent scintillator films were successfully prepared from the inorganic salt and 2-methoxyethanol solution containing polyvinylpyrrolidone(PVP) via sol-gel technique, and transmittance, photoluminescence, X-ray excitation emission spectral and spatial resolution, and a series of film properties were characterized. A film thickness of about 2.1 μm was achieved after 8 coatings. The thick film was homogeneous and crack free, and the transmittance was approximately 70% in its emission region. The spatial resolution of the thick film was 1.5 μm, which measured by the standard spatial resolution panels. An X-ray imageof fruit fly was obtained by using this thick film. Additionally, thesol-gel derived M′-type LuTaO4∶Eu3+thick film revealed excellent photoluminescence and X-ray excited luminescence performances. All results indicated that the M′-type LuTaO4∶Eu3+thick films have satisfied the essential requirements for applications in high-spatial-resolution X-ray imaging.
2016 Vol. 36 (02): 336-339 [Abstract] ( 389 ) PDF (2021 KB)  ( 148 )
340 Study on Hydrothermal Preparation and Luminescence Properties of Luminescent Material BaSrMg(PO4)2∶Eu3+
HU Qing-song, ZHU Cheng-jing, XIA Yue-yi, WANG Li-li, LIU Wen-han, PAN Zai-fa*
DOI: 10.3964/j.issn.1000-0593(2016)02-0340-05
Eu3+ doped BaSrMg(PO4)2 were prepared by a hydrothermal method. The crystal structure and morphology of BaSrMg(PO4)2∶Eu3+ phosphor were characterized by X-ray powder diffraction(XRD) and field emission scanning electron microscopy(FESEM). The effects of different pH values (5, 6, 7 and 8) and different reaction temperatures (120, 140, 160, 180 and 200 ℃) on the crystal structure and morphology of BaSrMg(PO4)2∶Eu3+ phosphor were studied in this paper. The results of XRD indicate that diffraction peaks are sharp and strong only when pH value is 6, meanwhile the FESEM shows the morphology is regular-shaped. The XRD patterns show amorphous halos superimposed with several weak sharp peaks for the samples preparing under the pH values of 5, 7 and 8. It indicates that these three samples are solid solution or mixed phases, which are in accord with the results of FESEM. From the fluorescence spectra, the peaks in the excitation spectra were assigned to the transition from 7F0 to 5D4, 5L8, 5L6 and 5D2, while the peaks of emission spectra corresponding to the transition of 5D17F1 and 5D07FJ (J= 0, 1, 2, 3 and 4). The strongest emission peak of the optimized phosphor located at 613 nm (5D07F2), excited by the main excitation peak with wavelength of 394 nm. The splitting of the emission peaks changes depends on pH values and temperatures, which indicating that luminescence properties is closely related to the crystal structure and morphology of particles.
2016 Vol. 36 (02): 340-344 [Abstract] ( 412 ) PDF (2213 KB)  ( 150 )
345 Fluorescence Properties and the Detection of Benzaldehyde of Lanthanide Complex with 2-Sufoterephthalalic Acid
LI Jia-jia, LI Rui, MA Xue, FAN Ting-ting, LIN Yi-qing, SONG Yu-ting, HAN Jing-qi, LI Xia*
DOI: 10.3964/j.issn.1000-0593(2016)02-0345-04
A new lanthanide coordination polymer, [Eu(2-stp)(2,2’-bipy)(H2O)]·H2O (2-stp=2-sufoterephthalalic acid, 2,2’-bipy=2,2’-bipyridine) was obtained by hydrothermal method. The crystal structure was determined by single crystal X-ray diffraction. The complex has a one-dimensional parallel double-chain structure. Eu3+ is a nine-coordinated by six O atoms from three 2-sufoterephthalalic acids, one water molecule and two N atoms from 2,2’-bipyridine. The fluorescence properties of the complex were studied. The complex shows the characteristics narrow emission of Eu3+ ion at 581, 594, 619, 654 and 698 nm, corresponding to 5D07FJ (J=0~4) transitions. The strongest emission peak is at 619 nm, corresponding to 5D07F2 transition for red light. Different organic solvents have different effects on the fluorescence intensity of the complex, and benzaldehyde exerts the most significant fluorescence quenching effect. So, this complex can be used as a fluorescent sensing probe for benzaldehyde.
2016 Vol. 36 (02): 345-348 [Abstract] ( 369 ) PDF (2267 KB)  ( 166 )
349 Research on the Highly Stable White LED with CdSe/ZnS Quantum Dot as Light Conversion Layer
CAO Jin2, ZHOU Jie1, XIE Jing-wei1, CHEN An-ping1, ZHANG Xue1, YIN Lu-qiao2, ZHANG Jian-hua2
DOI: 10.3964/j.issn.1000-0593(2016)02-0349-06
In accordance with the one-step synthesis, in this paper, we synthesized 510, 550 and 630 nm three emission peaks CdSe/ZnS core-shell quantum dots with high stability and high quantum yield whose quantum yield were 82%, 98% and 97%. We used the quantum dot material to replace the phosphor material, and mixed QDs with the silicone uniformly, then dispersed the QDs/silicone composites onto the blue InGaN LEDs to fabricate the QDs-WLEDs. By successively adding different colors of quantum dots for the preparation of quantum dot light converting layer, We investigated that how does the ratio of the three kind of quantum dots whose peaks were 510, 550 and 630 nm effect on the properties of the white LED devices. This paper also studied the mechanism of energy conversion between different colors of quantum dots. We also utilized the mechanism that the quantum dots effect on the white spectrum and color coordinates; we got the results of the optimization of the white device and the ratio of three-color quantum dots. The results show that when the quantum dot ratio is 24∶7∶10, white LED devices with high stability and high efficiency can be obtained, in the current range of 20~200 mA, the range of color temperature is from 4 607 to 5 920 K, the CIE-1931 coordinates is from (0.355 1,0.348 3) to (0.323 4,0.336 1), the color rendering index is from 77.6 to 84.2, and the highest power efficiency of the devices achieves to 31.69 lm·W-1 @ 20 mA. In addition, in order to further investigate the reason of stable device performance, We studied the effects of time, temperature, UV treatment on the stability of CdSe/ZnS QDs/silicone light conversion material, the results show that the excellent stability of the devices attributes to the stability of the one-step synthesis of core-shell structure of the quantum dot material, the final optimized device is a low-power high-quality white light source and the device has good application prospects in the field of standard white light source which can truly perceive the color and original features of objects.
2016 Vol. 36 (02): 349-354 [Abstract] ( 460 ) PDF (2328 KB)  ( 184 )
355 Testing Research of Transient Temperature Distribution for the Barrel Surface by Speckle Pattern Interferometry
LANG Wen-jie1, CHEN Guo-guang2, TIAN Xiao-li2, XIN Chang-fan2
DOI: 10.3964/j.issn.1000-0593(2016)02-0355-04
There are some problems in the traditional transient temperature test equipment. The thermal inertia is great, and can only be a single point of detection. To be able to achieve real-time monitoring for transient temperature distribution change of the gun body surface, the test system for transient temperature distribution was designed based on Speckle Pattern Interferometry (SPI) and spectroscopy. In the system, transient temperature change of the barrel led to slight deformation, and it was converted into speckle interference fringes by SPI technology. Spectral distribution function was obtained by the interference fringes by the Fourier transform, so the information of interference fringe deformation was incorporated into the frequency domain. The data of temperature distribution can be inverted on any sampling time by spectral distribution function. In experiments, the ZX-FB1 fiber optic thermometer was used to test transient temperature on a single point as the standard value. The center wavelength of the laser was 555 nm, and the speckle pattern interference fringes were collected by area array CCD. Image Recognition-Speckle Pattern Interferometry (IR-SPI) and Fourier Transform-Speckle Pattern Interferometry (FT-SPI) were used in experiments, the calculation of transient temperature was completed through two methods. Experimental results are that both methods can achieve transient temperature detection. But the FT-SPI is higher in terms of accuracy, and it can effectively overcome the gross error caused by the surface defects, paint wear and other similar problems.
2016 Vol. 36 (02): 355-358 [Abstract] ( 333 ) PDF (1304 KB)  ( 150 )
359 Air Dielectric Barrier Discharge Emission Spectrum Measurement and Particle Analysis of Discharge Process
SHEN Shuang-yan, JIN Xing*, ZHANG Peng
DOI: 10.3964/j.issn.1000-0593(2016)02-0359-05
The emission spectrum detection and diagnosis is one of the most common methods of application to the plasma. It provides wealth of information of the chemical and physical process of the plasma. The analysis of discharge plasma dynamic behavior plays an important role in the study of gas discharge mechanism and application. An air dielectric discharge spectrum measuring device was designed and the emission spectrum data was measured under the experimental condition. The plasma particles evolution was analyzed from the emission spectrum. The numerical calculation model was established and the density equation, energy transfer equation and the Boltzmann equation was coupled to analyze the change of the particle density to explain the emission spectrum characteristics. The results are that the particle density is growing with the increasing of reduced electric field. The particle density is one or two orders of magnitude difference for the same particle at the same moment for the reduced electric field of 40, 60 or 80 Td. A lot of N2(A3), N2(A3) and N2(C3) particles are generated by the electric field excitation. However, it transforms quickly due to the higher energy level. The transformation returns to the balance after the discharge of 10-6 s. The emission spectrometer measured in the experiments is mostly generated by the transition of excited nitrogen. The peak concentration of O2(A1), O2(B1) and O2(A3Σ+u) is not low compared to the excited nitrogen molecules. These particles energy is relatively low and the transition spectral is longer. The spectrometer does not capture the oxygen emission spectrum. And the peak concentration of O particles is small, so the transition emission spectrum is weak. The calculation results of the stabled model can well explain the emission spectrum data.
2016 Vol. 36 (02): 359-363 [Abstract] ( 397 ) PDF (3539 KB)  ( 200 )
364 Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra
LIU Ying, DONG Li-fang*, NIU Xue-jiao,ZHANG Chao
DOI: 10.3964/j.issn.1000-0593(2016)02-0364-04
The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N2 second positive band(C3Πu→B3Πg)are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N2 line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm(2P2→1S5) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges(SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and dim spot. In addition, the studies exert influences on the application of surface discharge and volume discharge in different fields.
2016 Vol. 36 (02): 364-367 [Abstract] ( 337 ) PDF (2253 KB)  ( 147 )
368 Study on Square Super-Lattice Pattern with Surface Discharge in Dielectric Barrier Discharge by Optical Emission Spectra
NIU Xue-jiao, DONG Li-fang*, LIU Ying, WANG Qian,FENG Jian-yu
DOI: 10.3964/j.issn.1000-0593(2016)02-0368-04
Square super-lattice pattern with surface discharge consisting of central spots and dim spots is firstly observed in the mixture of argon and air by using a dielectric barrier discharge device with water electrodes. By observing the image, it is found that the central spot is located at the centriod of its surrounding four dim spots. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The brightness of the central spot and is quite different from that of the dim spot, which indicates that the plasma states of the central spot and the dim spot may be differentiated. The optical emission spectrum method is used to further study the several plasma parameters of the central spot and the dim spot in different argon content. The emission spectra of the N2 second positive band (C3Πu→B3Πg) are measured, from which the molecule vibration temperatures of the central spot and the dim spot are calculated respectively. The broadening of spectral line 696.57 nm (2P2→1S5) is used to study the electron densities of the central spot and the dim spot. It is found that the molecule vibration temperature and electron density of the dim spot are higher than those of the central spot in the same argon content. The molecule vibration temperature and electron density of the central spot and the dim spot increase with the argon content increasing from 90% to 99.9%. The surface discharge induced by the volume discharge (VD) has the determinative effect on the formation of the dim spot. The experimental results above play an important role in studying the formation mechanism of surface discharge of square super-lattice pattern with surface discharge. In addition, the studies exert an influence on the application of surface discharge and volume discharge in different fields.
2016 Vol. 36 (02): 368-371 [Abstract] ( 458 ) PDF (2037 KB)  ( 171 )
372 Spectroscopic Study of Salbutamol Molecularly Imprinted Polymers
REN Hui-peng, GUAN Yu-yu, DAI Rong-hua, LIU Guo-yan, CHAI Chun-yan*
DOI: 10.3964/j.issn.1000-0593(2016)02-0372-07
In order to solve the problem of on-site rapid detection of salbutamol residues in feed and animal products, and develop a new method of fast detection of salbutamol on the basis of the molecular imprinting technology, this article uses the salbutamol (SAL) working as template molecule, methacrylic acid (MAA) working as functional monomer. On this basis, a new type of core-shell type salbutamol molecularly imprinted polymers were prepared with colloidal gold particles as triggering core. Superficial characteristics of the MIPs and the related compounds were investigated by ultraviolet (UV) spectra and infrared (IR) spectra, Raman spectra,Scanning electron microscopy (SEM) respectively. The results indicated that a stable hydrogen bonding complex has been formed between the carboxyl groups of SAL and MA with a matching ratio of 1∶1. The complex can be easily eluted by the reagent containing hydrogen bonding. The chemical binding constant K reaches -0.245×106 L2·mol-2. The possible binding sites of the hydrogen bonding was formed between the hydrogen atoms of —COOH in MA and the oxygen atoms of CO in SAL. IR and Raman spectrum showed that, compared with MA, a significant red shift of —OH absorption peak was manifested in MIPs, which proved that SAL as template molecule occurred a specific bond between MA. Red shift of stretching vibration absorption peak of CO was also detected in the un-eluted MIPs and obvious energy loss happened, which demonstrated a possible binding sites is SAL intramolecular of CO atom of oxygen. If the hydrogen atoms of —COOH in MA wanted to generate hydrogen bond. However, the shapes of absorption peak of other functional groups including CC, CO, and —OH were very similar both in MIPs and NIPs. Specific cavities were formed after the template molecules in MIPs were removed. It was proved by the adsorption experiment that the specific sites in these cavities highly match with the chemical and space structure of SAL. Besides,colloidal gold type core-shell molecularly imprinted polymers have looser surface, more cavities in the surface compared with ordinary molecularly imprinted polymers, which increased the effective area of adsorption to target molecules. So it have better performance in adsorption. Based on the principle that these cavities can specificly recognize and combine with target molecule in the test sample, and the excellent ability of colloidal gold core-shell molecularly imprinted polymers, the development of novel methods for fast determination of SAL based on the molecular imprinting technology can be expected in the near future.
2016 Vol. 36 (02): 372-378 [Abstract] ( 465 ) PDF (3028 KB)  ( 154 )
379 Use of Near-Infrared Hyperspectral Images to Differentiate Architectural Coatings with Different Qualities
JIANG Jin-bao, QIAO Xiao-jun, HE Ru-yan, TIAN Fen-min
DOI: 10.3964/j.issn.1000-0593(2016)02-0379-05
Architectural coatings sold in market fall into many categories which mean different models and qualities. The research plans to differentiate different kinds of architectural coatings in quality using hyperspectral technology. Near-Infrared hyperspectral images of four kinds of architectural coatings (in a descending quality order of brand A, B, C, and D) in same color were acquired. The optimal wavelengths were selected at 1 283 and 2 447 nm to differentiate the four kinds of coatings through ANOVA (Analysis of Variance) method. The band ratio index of R1 283/R2 447 was built and the results were segmented into the corresponding coatings, and the accuracies of segmentation were compared with that from Maximum Likely Classification (MLC). The results indicated all J-M distances are more than 1.8 except between C and D; the lowest accuracy of 87.54% in segmentation and 95.63% in MLC were both from brand D, and others’ accuracies all were over 90% in both ratio index and MLC. Therefore, the ratio index R1 283/R2 447 could be used to distinguish different kinds of architectural coatings. Also, the research could provide support for identification, quality acceptance, as well as conformity assessment of architectural coatings.
2016 Vol. 36 (02): 379-383 [Abstract] ( 367 ) PDF (1653 KB)  ( 183 )
384 Local Regression Algorithm Based on Net Analyte Signal and Its Application in Near Infrared Spectral Analysis
ZHANG Hong-guang, LU Jian-gang*
DOI: 10.3964/j.issn.1000-0593(2016)02-0384-04
To overcome the problems of significant difference among samples and nonlinearity between the property and spectra of samples in spectral quantitative analysis, a local regression algorithm is proposed in this paper. In this algorithm, net signal analysis method(NAS) was firstly used to obtain the net analyte signal of the calibration samples and unknown samples,then the Euclidean distance between net analyte signal of the sample and net analyte signal of calibration samples was calculated and utilized as similarity index. According to the defined similarity index, the local calibration sets were individually selected for each unknown sample. Finally, a local PLS regression model was built on each local calibration sets for each unknown sample. The proposed method was applied to a set of near infrared spectra of meat samples. The results demonstrate that the prediction precision and model complexity of the proposed method are superior to global PLS regression method and conventional local regression algorithm based on spectral Euclidean distance.
2016 Vol. 36 (02): 384-387 [Abstract] ( 372 ) PDF (1610 KB)  ( 152 )
388 Analysis and Discrimination of the Medicinal Plants Swertia Davidi Franch Based on Infrared Spectroscopy
DI Zhun1, 2, ZHAO Yan-li2, ZUO Zhi-tian2, LONG Hua1, ZHANG Xue3, WANG Yuan-zhong2*, LI Li1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0388-06
Fourier transform infrared spectroscopy combined with partial least squares discriminate analysis (PLS-DA) and hierarchical cluster analysis (HCA) were used to rapidly discriminate the Swertia davidi Franch which collected from different origins. The original infrared spectra data of different parts of all the 70 samples which collected from four different regions were preprocessed by automatic calibration, automatic smoothing, the first derivative and the second derivative. Then the processed data were imported into OMNIC 8.2 and the absorption peaks were compared; PLS-DA was performed by SIMCA-P+ 10.0 and the effect of discrimination of different origins was compared by 3D score plot of the first three principal components; the infrared spectral data were imported into SPSS 19.0 for HCA to compare classification results of different parts by the dendrogram. The results showed that: (1) There were differences among the spectra of the roots of different origins in the spectral peaks in 1 739, 1 647, 1 614, 1 503, 1 271, 1 243, 1 072 cm-1. The spectra of the stems of different origins showed differentiation in the wavelength in 1 503, 1 270, 1 246 cm-1; (2) The characteristic peaks of different parts of the same origin were different; (3) PLS-DA indicated that the data which were processed by automatic correction, automatic smoothing and second derivative have showed the best classification. In addition, the discrimination of roots which collected from different origins could be the best; (4) Tree diagram of HCA showed that the accuracy rate of cluster in roots, stems and leaves were 83%, 56%, and 70%, respectively. In conclusion: FTIR combined with PLS-DA and HCA can rapidly and accurately differentiate S. davidi that collected from different origins, the origin discrimination effect of different parts was clearly different that the classification of roots is the best, the second derivative could enhance the specificity of the samples, the classification in 3D score plot could be visualized and obvious.
2016 Vol. 36 (02): 388-393 [Abstract] ( 360 ) PDF (3812 KB)  ( 190 )
394 Study on Application of NIR Spectral Information Screening in Identification of Maca Origin
WANG Yuan-zhong, ZHAO Yan-li, ZHANG Ji, JIN Hang*
DOI: 10.3964/j.issn.1000-0593(2016)02-0394-07
Medicinal and edible plant Maca is rich in various nutrients and owns great medicinal value. Based on near infrared diffuse reflectance spectra, 139 Maca samples collected from Peru and Yunnan were used to identify their geographical origins. Multiplication signal correction (MSC) coupled with second derivative (SD) and Norris derivative filter (ND) was employed in spectral pretreatment. Spectrum range (7 500~4 061 cm-1 ) was chosen by spectrum standard deviation. Combined with principal component analysis-mahalanobis distance (PCA-MD), the appropriate number of principal components was selected as 5. Based on the spectrum range and the number of principal components selected, two abnormal samples were eliminated by modular group iterative singular sample diagnosis method. Then, four methods were used to filter spectral variable information, competitive adaptive reweighted sampling (CARS), monte carlo-uninformative variable elimination (MC-UVE), genetic algorithm (GA) and subwindow permutation analysis (SPA). The spectral variable information filtered was evaluated by model population analysis (MPA). The results showed that RMSECV(SPA)>RMSECV(CARS)>RMSECV(MC-UVE)>RMSECV(GA), were 2.14, 2.05, 2.02, and 1.98, and the spectral variables were 250, 240, 250 and 70, respectively. According to the spectral variable filtered, partial least squares discriminant analysis (PLS-DA) was used to build the model, with random selection of 97 samples as training set, and the other 40 samples as validation set. The results showed that, R2: GA>MC-UVE>CARS>SPA, RMSEC and RMSEP: GA<MC-UVE<CARS<SPA. For the spectral information selected by the four methods, GA, MC-UVE, CARS and SPA, the model prediction accuracy were 95.0%, 92.5%, 90.0% and 85.0%, respectively. Compared with the four methods, we could know that the origin discriminant models built based on spectra information filtered by the four methods possess good estimated performance. Among them, the model built based on the spectra information filtered by GA was the best, which could more accurately identify different regions Maca. The method was aimed to lay the foundation for traditional Chinese medicine identification and quality evaluation.
2016 Vol. 36 (02): 394-400 [Abstract] ( 391 ) PDF (3236 KB)  ( 195 )
401 Research Progress of Raman Spectroscopy on Dyestuff Identification of Ancient Relics and Artifacts
HE Qiu-ju1, 2, WANG Li-qin1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0401-07
As the birthplace of Silk Road, China has a long dyeing history. The valuable information about the production time,the source of dyeing material,dyeing process and preservation status were existed in organic dyestuff deriving from cultural relics and artifacts. However,because of the low contents,complex compositions and easily degraded of dyestuff,it is always a challenging task to identify the dyestuff in relics analyzing field. As a finger-print spectrum,Raman spectroscopy owns unique superiorities in dyestuff identification. Thus,the principle,characteristic,limitation,progress and development direction of micro-Raman spectroscopy (MRS/μ-Raman),near infrared reflection and Fourier transform Raman spectroscopy (NIR-FT-Raman), surface-enhanced Raman spectroscopy (SERS) and resonance raman spectroscopy (RRS) have been introduced in this paper. Furthermore, the features of Raman spectra of gardenia,curcumin and other natural dyestuffs were classified by MRS technology, and then the fluorescence phenomena of purpurin excitated with different wavelength laser was compared and analyzed. At last, gray green silver colloidal particles were made as the base,then the colorant of madder was identified combining with thin layer chromatography (TLC) separation technology and SERS,the result showed that the surface enhancement effect of silver colloidal particles could significantly reduce fluorescence background of the Raman spectra. It is pointed out that Raman spectroscopy is a rapid and convenient molecular structure qualitative methodology,which has broad application prospect in dyestuff analysis of cultural relics and artifacts. We propose that the combination of multi-Raman spectroscopy, separation technology and long distance transmission technology are the development trends of Raman spectroscopy.
2016 Vol. 36 (02): 401-407 [Abstract] ( 534 ) PDF (1722 KB)  ( 555 )
408 Study on the Temperature Dependent Phase Transformation of Raman Spectra for Cyclobutanol
ZHANG Huan-jun, CHENG Xue-rui*, REN Yu-fen, ZHU Xiang, YUAN Chao-sheng
DOI: 10.3964/j.issn.1000-0593(2016)02-0408-05
Cyclobutanol (C4H8O) is one of the four-membered ring type molecules, which usually adopts a non-planar equilibrium conformation, and the substituent group OH can adopt two positions relative to the puckered ring, the axial or the equatorial, giving rise to an additional degree of freedom and various molecular conformations. Additionally, temperature is one important thermodynamic parameter that greatly influents the structure and induces the possibility of conformational change or crystal change. As a consequence, there may be a number of phase transitions and molecular conformations for cyclobutanol under different temperature. In this paper, Raman and infrared spectroscopic technique were applied to investigate the vibration modes of cyclobutanol. The results indicate that the main component of the liquid cyclobutanol is equatorial-trans (Eq-t) conformer with a few Eq-g conformers at ambient condition. Then differential scanning calorimetry (DSC) and low temperature Raman spectroscopic were applied to study the phase transition of cyclobutanol during the cooling and heating process. It is observed that the Raman spectra and the intensities of these bands are not significantly changed during the cooling process. The results indicate that there is sill no presence of solidification especially cooling to 140K, which indicates that the cyclobutanol still remains the liquid state and supercooled state is observed during the cooling process. And this supercooled liquid is one metastable state, not in thermodynamic equilibrium. Further cooling to 138 K, the super-cooling liquid cyclobutanol will transform into the glassy state, accompanied with a small change of entropy. During the heating process, as the temperature is raised to 180 K, the Raman peaks became sharper and some new characteristic peaks appeared abruptly and a discontinuous change was observed in bandwidths versus temperature. And these new signatures can be maintained upon to 220 K, and then will disappear as the temperature increasing continuously. This result indicates the one crystal phase transition and a melting transition present at around 180 and 220 K. In addition, it can be observed that the component of Eq-g conformer increases, accompanied with the crystallization during heating at around 180 K. These results were helpful to understand the kinetics of the crystallization process of other small organic molecules.
2016 Vol. 36 (02): 408-412 [Abstract] ( 365 ) PDF (1523 KB)  ( 146 )
413 Revealing the Cell Structure and Formation of Bamboo with Confocal Raman Microscopy
LI Xiao-li1, ZHOU Bin-xiong1, ZHANG Yi2, YAO Yan-ming3, HE Yong1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0413-06
Parenchyma cell (PAC), transition tissue between parenchyma cell and fiber cell (TC) and fibre cell (FC) of bamboo were studied by confocal Raman microscopy in this paper. Partial least squares regression was applied to establish a quantitative differentiation model for the three types of cells. The result showed that the determination coefficients (R2) of calibration and validation were respectively 0.810 and 0.800, and the root mean square error (RMSE) were respectively 0.323 and 0.332. What’s more, three raman bands of 1 095, 1 319 and 1 636 cm-1, verified to the characteristic peaks of pectin, hemicellulose and lignin, were found to be the important bands for the differentiation. Subsequently, these three raman bands were used to establish a multiple linear regression (MLR) model, and the determination coefficients(R2) of calibration and validation of the model were respectively 0.644 and 0.643, and the root mean square error (RMSE) were respectively 0.442 and 0.443. This result showed that there existed obvious difference among the three types of cells in these three raman bands. Finally, the raman spectral signal processed by wavelet transform to eliminate baseline were used to chemical imaging analysis. These results showed a rather large microfibril angle between cellulose fibrils and fibre axis, which contributed to higher modulus and hardness of cells. Hemicellulose and cellulose have similar distribution in the raman chemical image, due to the connection of hemicellulose and cellulose microfiber through hydrogen bond and the closely combination under the action of van der Waals force. The cell corners (CC) and compound middle lamella (CML) were heavily lignified, and a gradual decrease of lignification from the outer layer to the inner layer of the three cells indicate that lignification was first occurred at the CC and CML, and the lignification was not fully completed.
2016 Vol. 36 (02): 413-418 [Abstract] ( 408 ) PDF (5257 KB)  ( 576 )
419 Correction Multiplicative Effects in Raman Spectra through Vector Angle Transformation
YAO Zhi-xiang1,3, SUN Zeng-qiang1, 3, SU Hui1, 3, YUAN Hong-fu2
DOI: 10.3964/j.issn.1000-0593(2016)02-0419-05
The linear relationship between the Raman spectral intensity and the analyte amount is frequently disrupted for a variety of complex reasons, which include these variations in laser source, focusing effect, sample scattering and refracting, so that causes poor quantitative results. As a whole, these disturbing effects can be divided to be additive and multiplicative, and the multiplicative effects are generally more difficult to be eliminated. A spectrum is a series data, also can be treated as a vector. In principle, unstable motions in spectrum intensity/amplitude corresponding to the module shifts for a vector, doesn’t impact the vector direction which is the essence of the vector, so it is reasonable to rewrite the data form on module to on space angle for the same measurement. This thesis employed a data transformation to eliminate the multiplicative effects within spectra, i. e., the spectrum signal on its amplitude has been transformed to be on the vector angles. The first step of the transformation is the selection of a stand vector which is near to the analyte and almost orthogonal to the background within the sample space; and the next step is to define a moving window, then to find out the angle between the sample vector (i. e. the transformed spectrum) and the stand vector within the window; while the window is moved along the spectrum data series, the transformation for vector angle (VA) series has been finished. The thesis has proved that an approximate linear quantitative relationship has been remained in the VA series. Multivariate calibration need full rank matrix which is combined by spectrum from variety samples, and variety VA series also can combine a full rank VA matrix, so the approximate linear VA matrix still perfectly meeting the demand for multivariate calibration. A mixed system consisted by methanol-ethanol-isopropanol has been employed to verify the eliminations to the multiplicative effects. These measuring values of the system are obtained at different Raman integral times and have remarkable multiplicative effects. In predicting results, the correlation coefficient (r) and the root mean squared error of prediction (RMSEP) from class PLS respectively are 0.911 9 and 0.110 2, and 0.906 0 and 0.100 8 are for the preprocessing by multiplicative scatter correction (MSC). In contrast, r and RMSEP under the VAPLS, presented by this thesis, respectively are 0.998 7 and 0.015 2 and are significantly better than others. The VAPLS has eliminated the multiplicative effects of Raman spectra and improved the accuracy of Raman quantitative analysis and it owes to the preprocessing of the vector angle transformation.
2016 Vol. 36 (02): 419-423 [Abstract] ( 338 ) PDF (1604 KB)  ( 205 )
424 EMD Time-Frequency Analysis of Raman Spectrum and NIR
ZHAO Xiao-yu1, FANG Yi-ming2, TAN Feng1, TONG Liang3, ZHAI Zhe4
DOI: 10.3964/j.issn.1000-0593(2016)02-0424-06
This paper analyzes the Raman spectrum and Near Infrared Spectrum (NIR) with time-frequency method. The empirical mode decomposition spectrum becomes intrinsic mode functions, which the proportion calculation reveals the Raman spectral energy is uniform distributed in each component, while the NIR’s low order intrinsic mode functions only undertakes fewer primary spectroscopic effective information. Both the real spectrum and numerical experiments show that the empirical mode decomposition (EMD) regard Raman spectrum as the amplitude-modulated signal, which possessed with high frequency adsorption property; and EMD regards NIR as the frequency-modulated signal, which could be preferably realized high frequency narrow-band demodulation during first-order intrinsic mode functions. The first-order intrinsic mode functions Hilbert transform reveals that during the period of empirical mode decomposes Raman spectrum, modal aliasing happened. Through further analysis of corn leaf’s NIR in time-frequency domain, after EMD, the first and second orders components of low energy are cut off, and reconstruct spectral signal by using the remaining intrinsic mode functions, the root-mean-square error is 1.001 1, and the correlation coefficient is 0.981 3, both of these two indexes indicated higher accuracy in re-construction; the decomposition trend term indicates the absorbency is ascending along with the decreasing to wave length in the near-infrared light wave band; and the Hilbert transform of characteristic modal component displays, 657 cm-1 is the specific frequency by the corn leaf stress spectrum, which could be regarded as characteristic frequency for identification.
2016 Vol. 36 (02): 424-429 [Abstract] ( 347 ) PDF (4360 KB)  ( 167 )
430 The Quantitative Analysis of Raman Spectroscopy to Sulfate Ion in Aqueous Solution
WANG Qian-qian, SUN Qiang*
DOI: 10.3964/j.issn.1000-0593(2016)02-0430-06
As a non-destructive and non-contact method, Raman spectroscopy has been widely applied in many research fields. Based on vibrational wavenumber, Raman spectroscopy is usually applied to determine the molecular species. Therefore, Raman quantitative analysis is necessary. In this study, according to the theoretical analysis of Raman intensity, Raman quantitative measurement should be fulfilled by relative intensity ratio, which can be divided into internal and external standards. This eliminates the influence of the measurement conditions. For aqueous solution, it is reasonable to treat the OH stretching band of water as an internal standard to determine the solute concentrations in aqueous solution. The Raman spectra of Na2SO4-H2O, K2SO4-H2O and NaCl-Na2SO4-H2O are recorded in the paper. In addition, the Raman OH stretching band of water can be fitted into two Gaussian sub-bands. The intensity proportion ISO2-4/IW is used to determine the molarity of sulfate in aqueous solution, where ISO2-4 represents the intensity of sulfate band and IW represents the sum of the two sub-bands of Raman OH stretching bands of water. Therefore, Raman spectroscopy can be utilized to measure the SO2-4 concentrations in aqueous solutions.
2016 Vol. 36 (02): 430-435 [Abstract] ( 368 ) PDF (2836 KB)  ( 396 )
436 Fe3O4-β-Cyclodextrin Polymer Nano Composites Solid-Phase Extraction-UV-Vis Spectrophotometry for Separation Analysis Malachite Green
FENG Gang1, 2, PING Wen-hui1, ZHU Xia-shi1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0436-06
In this paper, carboxymethyl-hydroxypropyl-β-cyclodextrin polymer modified magnetic particles Fe3O4 (CM-HP-β-CDCP-MNPs) were prepared and applied to magnetic solid phase extraction of malachite green combined with UV-Visible spectrometry detection. The synthesized magnetic particles were characterized by element analysis, Fourier transform infrared spectra and transmission electron microscopy. Several variables affecting the extraction and desorption of malachite green such as pH, the amount of adsorbent, the type and volume of eluent, extraction and desorption time, and temperature were investigated. Under the optimum conditions, malachite green could be adsorbed by CM-HP-β-CDCP-MNPs(RE%=92), and elution by C2H5OH(EE%=90). the preconcentration factor of the proposed method was approximately 7.5, the CM-HP-β-CDCP-MNPs could be used repeatedly for 5 times and offered better recovery. The linear range and detection limit (DL) were found to be 0.08~8.00 μg·mL-1 and 5.6 ng·mL-1 respectively. This technique had been successfully applied to the determination of malachite green in real samples. The inclusion interaction of CM-HP-β-CDCP-MNPs with malachite green was studied through FTIR.
2016 Vol. 36 (02): 436-441 [Abstract] ( 371 ) PDF (2816 KB)  ( 192 )
442 An On-Line Monitoring System for Nitrate in Seawater Based on UV Spectrum
LI Dan1, FENG Wei-wei2*, CHEN Ling-xin2, ZHANG Jun1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0442-03
Nitrate is one of the evaluation indicators of water quality, which is particularly important for water quality monitoring. A real-time on-line monitoring system of nitrate in water is introduced in this paper. And the ultraviolet absorption technology (190~370 nm) with partial least squares method is used to detect nitrate concentration. The automated online system based on ultraviolet absorption spectrum is capable of analyzing samples without any sample preservation and without contamination problems. This system is fast, reliable, and sensitive enough for continuous use on monitoring stations and nitrate concentration can also be determined directly via its ultraviolet absorption spectrum. This system uses flow sample cell with 1cm optical path length, and a reference light is used to eliminate system error. The correlation coefficient for a linear function of the nitrate concentrations is 0.999 98. So the results of the system model test are in good correlation with the laboratory ones. Data collected has been analyzed statistically to determine how system model behave throughout the test, with special attention being paid to error analysis. As the average relative error is 0.65%, this system has greater stability and higher accuracy. The results of nitrate measurements by the field seawater tests in Yantai coast are obtained, which nitrate concentrations are about 0.2 mg·L-1 in seawater, and the recoveries of samples for standard recovery tests are in 95%~110%, it shows that this system is accurate, reliability and practicability and could be developed for detected nitrate concentration in natural water.
2016 Vol. 36 (02): 442-444 [Abstract] ( 378 ) PDF (1181 KB)  ( 200 )
445 Discrimination of Crude Oil Samples Using Laser-Induced Time-Resolved Fluorescence Spectroscopy
HAN Xiao-shuang1, 2, LIU De-qing1, LUAN Xiao-ning1, GUO Jin-jia1, LIU Yong-xin2, ZHENG Rong-er1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0445-04
The Laser-induced fluorescence spectra combined with pattern recognition method has been widely applied in discrimination of different spilled oil, such as diesel, gasoline, and crude oil. However, traditional three-dimension fluorescence analysis method, which is not adapted to requirement of field detection, is limited to laboratory investigatio ns. The development of oil identification method for field detection is significant to quick response and operation of oil spill. In this paper, a new method based on laser-induced time-resolved fluorescence combined with support vector machine (SVM) model was introduced to discriminate crude oil samples. In this method, time-resolved spectra data was descended into two dimensions with selecting appropriate range in time and wavelength domains respectively to form a SVM data base. It is found that the classification accurate rate increased with an appropriate selection. With a selected range from 54 to 74 ns in time domain, the classification accurate rate has been increased from 83.3% (without selection) to 88.1%. With a selected wavelength range of 387.00~608.87 nm, the classification accurate rate of suspect oil was improved from 84% (without selection) to 100%. Since the detection delay of fluorescence lidar fluctuates due to wave and platform swing, the identification method with optimizing in both time and wavelength domains could offer a better flexibility for field applications. It is hoped that the developed method could provide some useful reference with data reduction for classification of suspect crude oil in the future development.
2016 Vol. 36 (02): 445-448 [Abstract] ( 359 ) PDF (2091 KB)  ( 179 )
449 Analysis of Three Polycyclic Aromatic Hydrocarbons in Solution Based on Two-Dimensional Fluorescence Correlation Spectroscopy
ZHOU Chang-hong1, 2, ZHAO Mei-rong1*, YANG Ren-jie2*, ZHU Wen-bi3, DONG Gui-mei2
DOI: 10.3964/j.issn.1000-0593(2016)02-0449-05
Polycyclic aromatic hydrocarbons (PAHs) are listed as the priority pollutants. It is difficult to resolve effectively the peaks of PAHs by conventional one-dimensional fluorescence spectroscopy due to its low content and the overlapping fluorescence peaks. In this paper, the two-dimensional (2D) fluorescence correlation spectroscopy will be applied to the analysis of highly overlapped fluorescence spectra of the mixed solution of anthracene, phenanthrene and pyrene. According to the research goals, three mixed systems and a total of 27 samples, are to be prepared with different concentrations of three PAHs. Concentrations of three PAHS are monotonically increasing or decreasing in each mixed system. Then the 2D fluorescence correlation spectrum of each mixed systems will be calculated under the perturbation of the concentration of anthracene, phenanthrene and pyrene in solution. There are seven strong autopeaks at 425, 402, 381, 373, 365, 393 and 347 nm in synchronous 2D correlation spectrum. The fluorescence peak of phenanthrene at 347 nm is uncovered in three mixed systems, so the band at 347 nm is to be used as clues for further assignment. According to positive or negative cross peaks at 347 nm in synchronous 2D correlation spectrum,we can know that the peaks at 402, 381, 425 and 452 nm are assigned to anthracene, the peaks at 373 and 393 nm are assigned to pyrene,and the peaks at 365, 356 and 347 nm are assigned to phenanthrene. The fluorescence peak of phenanthrene at 385 nm is shown in asynchronous 2D correlation spectrum; it means the spectral resolution of asynchronous spectrum is better than the synchronous spectrum. The results are that it is feasible to analyze serious overlapping multi-component PAHs using two-dimensional fluorescence correlation spectroscopy, which can be extended to the detection of other pollutants in the air.
2016 Vol. 36 (02): 449-453 [Abstract] ( 391 ) PDF (3661 KB)  ( 197 )
454 Investigation of Multi-Angle Polarization Properties of Vegetation Based on RSP
JIAO Jian-nan, ZHAO Hai-meng, YANG Bin, YAN Lei*
DOI: 10.3964/j.issn.1000-0593(2016)02-0454-05
Polarization detection provides us with novel information to reflect the target attribute. Compared with traditional remote sensing methods, multi-angle polarization has relatively stable correlation and regularity. RSP(research scanning polarimeter)is an airborne prototype for the APS(aerosol polarimetery sensor) developed by the USA, which can provide with us the polarization detection information of 9 channels. We can get optical properties and physical characteristics of vegetation by analyzing stable multi-angle and multi-band polarization detection information from preprocessing scanning polarization data of flight test. In this paper, after making registration based on flight attitude information, a comparative analysis is made between characteristics of reflectance and polarization reflectance with visible light and near infrared band of the view zenith angles between -30 degree and 65 degree , based on dense area and sparse area(close to bare field) of vegetation. The results show that both dense area and sparse area demonstrate regular characteristics of polarization degree. The area close to hot spot area has highest reflectance energy. In contrast, it has relatively least energy of polarization degree, which can prevent strong reflectance energy from influencing the stability of detector. Because the degree of polarization in dense area of vegetation is higher than that in sparse area at visible light band while that in concentration area of vegetation is lower than sparse area at near infrared light band, it shows that the visible light band information of dense area of vegetation that the sensor received is dominated by single scattering while the near infrared light band information of dense area of vegetation is dominated by multiple scattering.
2016 Vol. 36 (02): 454-458 [Abstract] ( 306 ) PDF (4319 KB)  ( 154 )
459 Study on Microwave Co-Pyrolysis of Low Rank Coal and Circulating Coal Gas
ZHOU Jun1,2, YANG Zhe1, LIU Xiao-feng3, WU Lei4, TIAN Yu-hong1,2, ZHAO Xi-cheng1,2
DOI: 10.3964/j.issn.1000-0593(2016)02-0459-07
The pyrolysis of low rank coal to produce bluecoke, coal tar and gas is considered to be the optimal method to realize its clean and efficient utilization. However, the current mainstream pyrolysis production technology generally has a certain particle size requirements for raw coal, resulting in lower yield and poorer quality of coal tar, lower content of effective components in coal gas such as H2, CH4, CO, etc. To further improve the yield of coal tar obtained from the pyrolysis of low rank coal and explore systematically the effect of microwave power, pyrolysis time and particle size of coal samples on the yield and composition of microwave pyrolysis products of low rank coal through the analysis and characterization of products with FTIR and GC-MS, introducing microwave pyrolysis of low rank coal into the microwave pyrolysis reactor circularly was suggested to carry out the co-pyrolysis experiment of the low rank coal and coal gas generated by the pyrolysis of low rank coal. The results indicated that the yield of the bluecoke and liquid products were up to 62.2% and 26.8% respectively when the optimal pyrolysis process conditions with the microwave power of 800W, pyrolysis time of 40min, coal samples particle size of 5~10 mm and circulating coal gas flow rate of 0.4 L·min-1 were selected. The infrared spectrogram of the bluecoke under different microwave power and pyrolysis time overlapped roughly. The content of functional groups with —OH,CO,CC and C—O from the bluecoke through the pyrolysis of particle size coal samples had a larger difference. To improve microwave power, prolonging pyrolysis time and reducing particle size of coal samples were conducive to converting heavy component to light one into coal tar.
2016 Vol. 36 (02): 459-465 [Abstract] ( 332 ) PDF (3195 KB)  ( 152 )
466 An Incoherent Broadband Optical Cavity Spectroscopy for Measuring Weak Absorption Cross Section of Sulfur Dioxide
DUAN Jun1, QIN Min1*, FANG Wu1, HU Ren-zhi1, LU Xue1, SHEN Lan-lan1, WANG Dan1, XIE Pin-hua1, 2, LIU Jian-guo1, 2, LIU Wen-qing1, 2
DOI: 10.3964/j.issn.1000-0593(2016)02-0466-05
As a highly sensitive detection technology, incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) have successfully measured a variety of trace gases. According to the principle of cavity enhanced absorption spectroscopy, if the accurate concentration of the target gas, the curve of the mirror reflectance, effective absorption path length, the light intensity of the absorbing gas and non-absorbing gas are known, the absorption cross section of the absorption gas can be measured. The accurate measurements of absorption cross section are necessary for satellite retrievals of atmospheric trace gases and the atmospheric research. This paper describes an incoherent broadband cavity enhanced absorption spectroscopy(IBBCEAS) instrument with 365 nm LED as the light source for measuring absorption cross section of SO2 from 357 to 385 nm which is arising from the spin-forbidden a3B1X1A1 transition. In comparison to the literature absorption cross section of SO2, and correlation coefficient r is 0.997 3. The result shows the potential of the IBBCEAS system for measuring weak absorption cross section.
2016 Vol. 36 (02): 466-470 [Abstract] ( 378 ) PDF (2640 KB)  ( 501 )
471 Spatial and Temporal Variations in Spectrum-Derived Vegetation Growth Trend in Qinghai-Tibetan Plateau from 1982 to 2014
WANG Zhi-wei1,2,3, WU Xiao-dong1, YUE Guang-yang1, ZHAO Lin1*, WANG Qian1, NAN Zhuo-tong1, QIN Yu1, WU Tong-hua1, SHI Jian-zong1, ZOU De-fu1,2
DOI: 10.3964/j.issn.1000-0593(2016)02-0471-07
Recently considerable researches have focused on monitoring vegetation changes because of its important role in regulating the terrestrial carbon cycle and the climate system. There were the largest areas with high-altitudes in the Qinghai-Tibet Plateau (QTP), which is often referred to as the third pole of the world. And vegetation in this region is significantly sensitive to the global warming. Meanwhile NDVI dataset was one of the most useful tools to monitor the vegetation activity with high spatial and temporal resolution, which is a normalized transform of the near-infrared radiation (NIR) to red reflectance ratio. Therefore, an extended GIMMS NDVI dataset from 1982—2006 to 1982—2014 was presented using a unary linear regression by MODIS dataset from 2000 to 2014 in QTP. Compared with previous researches, the accuracy of the extended NDVI dataset was improved again with consideration the residuals derived from scale transformation. So the model of extend NDVI dataset could be a new method to integrate different NDVI products. With the extended NDVI dataset, we found that in growing season there was a statistically significant increase (0.000 4 yr-1, r2=0.585 9, p<0.001) in QTP from 1982 to 2014. During the study period, the trends of NDVI were significantly increased in spring (0.000 5 yr-1, r2=0.295 4,p=0.001), summer (0.000 3 yr-1, r2=0.105 3,p=0.065) and autumn respectively (0.000 6 yr-1, r2=0.436 7,p<0.001). Due to the increased vegetation activity in Qinghai-Tibet Plateau from 1982 to 2014, the magnitude of carbon sink was accumulated in this region also at this same period. Then the data of temperature and precipitation was used to explore the reason of vegetation changed. Although the trends of them are both increased, the correlation between NDVI and temperature is higher than precipitation in vegetation growing season, spring, summer and autumn. Furthermore, there is significant spatial heterogeneity of the changing trends for NDVI, temperature and precipitation at Qinghai-Tibet Plateau scale.
2016 Vol. 36 (02): 471-477 [Abstract] ( 413 ) PDF (5119 KB)  ( 558 )
478 Optical Analysis of the Interaction of Mercaptan Derivatives of Nanogold Particles with Carcinoembryonic Antigen
ZENG Hong-juan, ZHAO Ran-lin, WANG De-shun, LI Cai-xia, LIU Yi-yao
DOI: 10.3964/j.issn.1000-0593(2016)02-0478-04
Gold nanoparticles (AuNPs) have been the subject of intense research for use in biomedicine over the past couple of decades. AuNPs, also referred to as colloidal gold, possess some astounding optical and physical properties that have earned them a prime spot among the new promising tools for medical applications. Today, AuNPs are offered to provide the clinical laboratory with more sensitive, faster, and simpler assays, which are also cost-effective. AuNPs can be used to develop point-of-care tests and novel testing strategies such as in drug targeting, disease detection, molecular recognition, and biological labels. The typical structure of AuNPs is spherical nano-sized gold particles, but they can also be composed of a thin gold shell surrounding a dielectric core, such as silica (gold nanoshells). their size range from 0.8 to 250 nm and are characterized by high absorption coefficients. AuNPs have some unique optical properties, such as enhanced absorption and scattering, where the absorption cross-section of AuNPs is 4~5 orders of magnitude greater than that of rhodamine 6G. When AuNPs aggregate, interaction of locally adjacent AuNPs (plasmon-plasmon interaction) shifts their color to blue. Thus, the binding of AuNP-labeled entities to their respective target would lead to aggregation of the nanoparticles and a detectable shift in the optical signal. The strong absorption of AuNPs can also be used in colorimetric detection of analytes by measuring changes in the refractive index of the AuNP’s environment caused by adsorption of the target analytes. However, a large number of surface atoms of nanoparticles have huge surplus bonding ability, because of surface effect of gold nanoparticles, result in reuniting and sinking among the nanoparticles which make them unstable. In order to detect traces of carcinoembryonic antigen, one of the tumor targets, a new kind of gold nanoparticle with hyperchormic effect and fluorescence sensitization effect material needs to be prepared. In this paper, novel mercaptan derivative of nanogold particles are prepared and studied using transmission electron microscopy (TEM), ultraviolet-visible absorption spectra (UV-Vis), fluorescence emission (FE) spectrum and infrared spectrum (IR) methods. The UV-Vis and FE results show the presence of new ligands mercaptan, more electrons from the orbit of ligand which can excite to the central ion related orbits and increase fluorescence of gold. Fluorescence sensitization effect was observed when mercaptan derivatives of nanogold interacted with carcinoembryonic antigen (CEA) and no fluorescence sensitization effect was found when nanogold interacted with carcinoembryonic antigen (CEA). The study of CEA hyperchromic mechanism of mercaptan derivatives nanogold and the CEA by the method of infrared spectrum, shows that the randomized OH bonds in the Au-protein interaction, showed more on the outside of the plane of bending vibration after the interaction with the mercaptan derivative nanogold, making the energy transfer from mercaptan derivatives nanogold to protein easy; leading to its fluorescence sensitization effect.
2016 Vol. 36 (02): 478-481 [Abstract] ( 378 ) PDF (1793 KB)  ( 208 )
482 High Throughput Screening Analysis of Preservatives and Sweeteners in Carbonated Beverages Based on Improved Standard Addition Method
WANG Su-fang1, 2, LIU Yun1, GONG Li-hua1, DONG Chun-hong3, FU De-xue3, WANG Guo-qing1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0482-05
Simulated water samples of 3 kinds of preservatives and 4 kinds of sweeteners were formulated by using orthogonal design. Kernel independent component analysis (KICA) was used to process the UV spectra of the simulated water samples and the beverages added different amounts of the additive standards, then the independent components (ICs), i.e. the UV spectral profiles of the additives, and the ICs’ coefficient matrices were used to establish UV-KICA-SVR prediction model of the simulated preservatives and sweeteners solutions using support vector regression (SVR) analysis. The standards added beverages samples were obtained by adding different amounts level of additives in carbonated beverages, their UV spectra were processed by KICA, then IC information represented to the additives and other sample matrix were obtained, and the sample background can be deducted by removing the corresponding IC, other ICs’ coefficient matrices were used to estimate the amounts of the additives in the standard added beverage samples based on the UV-KICA-SVR model, while the intercept of linear regression equation of predicted amounts and the added amounts in the standard added samples is the additive content in the raw beverage sample. By utilization of chemometric “blind source separation” method for extracting IC information of the tested additives in the beverage and other sample matrix, and using SVR regression modeling to improve the traditional standard addition method, a new method was proposed for the screening of the preservatives and sweeteners in carbonated beverages. The proposed UV-KICA-SVR method can be used to determine 3 kinds of preservatives and 4 kinds of sweetener in the carbonate beverages with the limit of detection (LOD) are located with the range 0.2~1.0 mg·L-1, which are comparable to that of the traditional high performance liquid chromatographic (HPLC) method.
2016 Vol. 36 (02): 482-486 [Abstract] ( 372 ) PDF (1230 KB)  ( 178 )
487 Study of Paints and Drawing Techniques of Fine Brushwork Yunlong Ripples Painting in Qing Dynasty
HAO Sheng-cai1, SHI Ji-long1, WANG Ji-gang1, HE Qiu-ju2, QI Xiao-kun1, ZHOU Zhong1,3, ZHOU Wen-hua1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0487-04
In order to study the paints and techniques of decorative patterns of dragon among clouds and water waves, the materials based on a Qing Dynasty meticulous painting were measured by three-dimensional video microscopy, Raman microscopy and energy dispersive X-ray fluorescence spectroscopy. The results showed that the green clothes was firstly colored by Paris green, the decorative patterns of dragon among clouds and water waves were then painted by hematite, the edge was delineated by brass powder at last. The dark yellow area within the decorative patterns was presented due to the interaction of green and red paints. In addition, ultramarine blue was checked in the painting. According to the first synthesized time of ultramarine blue and Paris green, we can make sure the time limit of the painting finished.
2016 Vol. 36 (02): 487-490 [Abstract] ( 434 ) PDF (2692 KB)  ( 177 )
491 Measurement of Nitrogen Content in Lettuce Canopy Using Spectroscopy Combined with BiPLS-GA-SPA and ELM
GAO Hong-yan, MAO Han-ping*, ZHANG Xiao-dong
DOI: 10.3964/j.issn.1000-0593(2016)02-0491-05
Nitrogen fertilizer is necessary to improve yield and quality of lettuce. Spectroscopy is one of the most effective techniques used to detect crop nitrogen content. In this study, canopy reflectance spectra were acquired under five levels of nitrogen, and then were Savitzky-Golay smoothed, the first-order derivative spectra were calculated from the smoothed spectra to eliminate noise effects. Backward interval partial least squares (BiPLS), genetic algorithm (GA) and successive projections algorithm (SPA) were combined to select the efficient wavelengths. The number of variables was decreased from 2 151 to 8. The optimal intervals or variables were used to build multivariable linear regression (MLR) model, radial basis function neural network (RBFNN) models and extreme learning machine (ELM) models. This work proved that the results of BiPLS-GA-SPA-ELM model was superior to others with RMSEC was 0.241 6%, Rc was 0.934 6, RMSEP was 0.284 2% and Rp was 0.921 8. Our research results may provide a foundation for nutrition regulation and developing instrument.
2016 Vol. 36 (02): 491-495 [Abstract] ( 360 ) PDF (2177 KB)  ( 176 )
496 Study of Cervical Exfoliated Cell’s DNA Quantitative Analysis Based on Multi-Spectral Imaging Technology
WU Zheng, ZENG Li-bo*, WU Qiong-shui*
DOI: 10.3964/j.issn.1000-0593(2016)02-0496-06
The conventional cervical cancer screening methods mainly include TBS (the bethesda system) classification method and cellular DNA quantitative analysis, however, by using multiple staining method in one cell slide, which is staining the cytoplasm with Papanicolaou reagent and the nucleus with Feulgen reagent, the study of achieving both two methods in the cervical cancer screening at the same time is still blank. Because the difficulty of this multiple staining method is that the absorbance of the non-DNA material may interfere with the absorbance of DNA, so that this paper has set up a multi-spectral imaging system, and established an absorbance unmixing model by using multiple linear regression method based on absorbance’s linear superposition character, and successfully stripped out the absorbance of DNA to run the DNA quantitative analysis, and achieved the perfect combination of those two kinds of conventional screening method. Through a series of experiment we have proved that between the absorbance of DNA which is calculated by the absorbance unmixxing model and the absorbance of DNA which is measured there is no significant difference in statistics when the test level is 1%, also the result of actual application has shown that there is no intersection between the confidence interval of the DNA index of the tetraploid cells which are screened by using this paper’s analysis method when the confidence level is 99% and the DNA index’s judging interval of cancer cells, so that the accuracy and feasibility of the quantitative DNA analysis with multiple staining method expounded by this paper have been verified, therefore this analytical method has a broad application prospect and considerable market potential in early diagnosis of cervical cancer and other cancers.
2016 Vol. 36 (02): 496-501 [Abstract] ( 372 ) PDF (2864 KB)  ( 166 )
502 Hyperspectral Detection Model for Soil Dispersion in Zhouqu Debris Flow Source Region
WANG Qin-jun1,2, WEI Yong-ming1, CHEN Yu1,2*, CHEN Jia-ge3, LIN Qi-zhong1
DOI: 10.3964/j.issn.1000-0593(2016)02-0502-09
Sensitive band positions, models and the principles of soil dispersion detected by hyperspectral remote sensing were firstly discussed according to the results of soil dispersive hyperspectral remote sensing experiment. Results showed that, (1) signals and noises could be separated by Fourier transformation. A finely mineral identification system was developed to remove spectral noises and provide highly accurate data for establishing soil dispersive model; (2) Soil dispersive hyperspectral remote sensing model established by the multiple linear regression method was good at soil dispersion forecasting for the high correlation between sensitive bands and the soil dispersions. (3) According to mineral spectra, soil minerals and their absorbed irons were reflected by sensitive bands which revealed reasons causing soils to be dispersive. Sodium was the closest iron correlated with soil dispersion. The secondary was calcite, montmorillonite and illite. However, the correlation between soil dispersion and chlorite, kaolinite, PH value, quartz, potassium feldspar, plagioclase was weak. The main reason was probably that sodium was low in ionic valence, small ionic radius and strong hydration forces; calcite was high water soluble and illite was weak binding forces between two layers under high pH value.
2016 Vol. 36 (02): 502-510 [Abstract] ( 356 ) PDF (2835 KB)  ( 163 )
511 Study on Visual Identification of Corn Seeds Based on Hyperspectral Imaging Technology
WU Xiang, ZHANG Wei-zheng, LU Jiang-feng, QIU Zheng-jun*, HE Yong
DOI: 10.3964/j.issn.1000-0593(2016)02-0511-04
The seed purity is an important indicator of seed quality. The paper proposes a visual identification method of corn seed based on the near-infrared (874~1 734 nm) hyperspectral image technology. Hyperspectral image data of 4 cultivars of a total of 384 corn seed samples will be acquired. Then 288 of samples are to be selected randomly as the calibration set, and the remaining 96 samples will be used for the prediction set. After inspection of the near-infrared spectral curves, 7 effective wavelengths (EWs) are to be selected by successive projection algorithm (SPA). And then 7 EWs of the calibration set will be used as input to build a partial least squares (PLS) model. Good results are to be obtained with RC=0.917 7, RMSECV=0.444 2; RCV=0.911 5, RMSECV=0.459 9. And the total identification rate of the developed PLS model will be 78.5% for the calibration set and 70.8% for the prediction set. Finally, average spectral data of each corn seed in a hyperspectral image will be extracted by image process technology, and used as input of the developed SPA-PLS model. In the produced identification map, different colors are to be used to represent different predicted cultivars. 3 mixture samples of corn seeds will be identified, and help to achieve satisfied visual effects. The result indicates that, by means of the visual identification technology we could intuitively observe the distribution of corn seeds of different cultivars in mixture samples. The research provides help for the identification and screening of seeds in agricultural production.
2016 Vol. 36 (02): 511-514 [Abstract] ( 460 ) PDF (2331 KB)  ( 519 )
515 Detection of Late Blight Disease on Potato Leaves Using Hyperspectral Imaging Technique
HU Yao-hua1, PING Xue-wen1, XU Ming-zhu1, SHAN Wei-xing2, HE Yong3*
DOI: 10.3964/j.issn.1000-0593(2016)02-0515-05
Hyperspectral imaging feature on potato leaves stressed by late blight was studied in the present paper. The experiment used 60 potato leaves. Among those 60 potato leaves, 48 leaves were vitro inoculated with pathogen of potato late blight, the rest 12 leaves were used as control samples. The leaves were observed for 7 continuous days before and after inoculated and samples including healthy and infested were acquired. Hyperspectral data of healthy and infected potato samples of different disease severity were obtained by the hyperspectral imaging system from 374 to 1 018 nm and then extract spectral data of region of interest(ROI) from those hyperspectral data by the ENVI software. In order to improve the signal-to-noise ratio, the spectral data were preprocessed using different pretreatment methods such as moving average smoothing, normalization, derivative, baseline etc. The least squares-support vector machine(LS-SVM) models were developed based on the raw and those preprocessed data. Among the nine models, the model that used the raw data and the data after the spectroscopic transformation performed best with the discrimination of 94.87%. It was demonstrated that it is realized to determine the potato late blight disease of different disease severity using hyperspectral imaging technique.
2016 Vol. 36 (02): 515-519 [Abstract] ( 386 ) PDF (1316 KB)  ( 549 )
520 Spectral Characteristics of Spring Maize Varieties with Different Heat Tolerance to High Temperature
TAO Zhi-qiang1, 2, CHEN Yuan-quan1, ZOU Juan-xiu1, 4, LI Chao3, YUAN Shu-fen1, YAN Peng1, SHI Jiang-tao3, SUI Peng1*
DOI: 10.3964/j.issn.1000-0593(2016)02-0520-07
This paper discussed the response of spectral characteristics on high temperature at grain filling stage of different spring maize varieties by adopting two spectrometer (SPAD-502 Chlorophyll Meter and Sunscan Plant Canopy Analyzer), and analyzed the impact of high temperature on the photosynthetic properties of spring maize in North China Plain. The test was conductedfrom the year 2011 to 2012 in Wuqiao County, Hebei Province. This test chose three different varieties, i.e. Tianyu 198 (TY198), Xingyu 998 (XY998) and Tianrun 606 (TR606), then two sowing date (April 15th and April 25th) was set. We analyzed chlorophyll relative content (SPAD), leaf area index (LAI) and photosynthetically active radiation (PAR) at grain filling stage. The results showed that the days of daily maximum temperature above 33 ℃ and the mean day temperature at grain filling stage in spring maize sowing on April 15th increased 3.5 d and 0.8 ℃, respectively, compared to that sowing on April 25th, moreover the sunshine hours, rainfall, diurnal temperature and length of growing period were similar. Compared with XY998 and TR606, TY198’s stress tolerance indices (STI) increased by 2.9% and 11.0%, respectively. According to STI from high to low order, TY198, XY998 and TR606 respectively as heat resistant type, moderate heat resistant type and thermolabile type variety. TY198, compared with XY998 and TR606 sowing on April 15th, yield increased by 4.1% and 13.7%, SPAD increased by 12.5% and 19.6%, LAI increased by 5.3% and 5.6%, PAR increased by 4.0% and 14.0%. Sowing on April 15th, yield increased by 1.3% and 2.8%, SPAD increased by 3.5% and 6.0%, LAI increased by 1.7% and 4.1%, PAR increased by -4.4% and 0.9%. Three varieties had significant yield differences in the environment of high temperature stress, heat resistant type have significant (p<0.05) advantage in the aspect of yield, SPAD and LAI. The production of TY198, XY998 and TR606 sowing on April 15th compared to that sowing on April 25th decreased by 3.2%, 5.9% and 12.6%, and SPAD decreased by 8.6 %, 12.4% and 15.7%, LAI decreased by 11.7%, 17.6% and 19.8%, PAR decreased by 3.4%, 11.3% and 14.5%; STI had a significant negatively correlated with SPAD fall range (r=-0.883, p<0.05) and LAI fall range (r=-0.853, p<0.05), and highly significantly negatively correlated with PAR fall range (r=-0.923, p<0.01); while SPAD fall range and PAR fall range showed a significant positive correlation (r=0.872, p<0.05); LAI fall range and PAR fall range were significantly positive correlation (r=0.943, p<0.05). In conclusion, heat tolerant type varieties of spring maize under high temperature stress at gain filling stage could maintain a relatively high content of chlorophyll at the individual level, a relatively high leaf area at the group level, and then keep a higher luminous energy interception and utilization, and weakened inhibition magnitude of high temperature on photosynthetic capacity, reduced the yield fall range, then achieved high and stable yield. The heat tolerance in varieties could be one of the main indicators for identification and evaluation the response to high temperature by spectral characteristics (SPAD, LAI and PAR). Thus it provides a basis by using spectral characteristics to study heat tolerance on maize.
2016 Vol. 36 (02): 520-526 [Abstract] ( 361 ) PDF (1654 KB)  ( 161 )
527 Determination of Total Sulfur Dioxide in Chinese Herbal Medicines via Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry
WANG Xiao-wei1, LIU Jing-fu2, GUAN Hong3, WANG Xiao-yan1, SHAO Bing1*, ZHANG Jing1, LIU Li-ping1, ZHANG Ni-na1
DOI: 10.3964/j.issn.1000-0593(2016)02-0527-05
As an important treatment method, sulfur fumigation plays an essential role in the production and preservation of traditional Chinese herbal medicines. Although there is strict regulation on the use of sulfur dioxide, the abuse of sulfur dioxide still occurred from time to time. And the public faces a high risk of exposure. Because of the poor precision and tedious preparation procedures of traditional recommended titration, the accurate and convenient determination of sulfur dioxide in Chinese herbal medicines is still a critical analytical task for medicines safety and the public health. In this study, an accurate, high-throughput, and convenient method for the absolute determination of SO2 in Chinese herbal medicines based on triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) technique is developed. The study compared the quantitative ability for sulfur when the ICP-MS operated under traditional single quadrupole (QMS) mode and novel triple quadrupole (MS/MS) mode with three Reaction/Collision cell condition (no gas, helium, and oxygen). The result indicated that when the concentration of sulfate ranging from 0.5 to 100 mg·L-1, isotopic 34S can be selected as quantitative ion either the ICP-MS operated under the QMS mode or MS/MS mode. The use of helium in the Reaction/Collision cell decreased the single intensity of background ions. Better than QMS mode, the MS/MS mode can effectively reduced background interference. But there are no significant differences about the linear range and limit of detection. However, when the ICP-MS operated under MS/MS mode and oxygen was used as reaction gas in the Reaction/Collision cell, the ICP-MS/MS provided an interference-free performance, the linear range and limit of detection improved significantly. Either 32S or 34S exhibits an excellent linearity (r>0.999) over the concentration range of 0.02~100 mg·L-1, with a limit of detection of 5.48 and 9.76 μg·L-1 for 32S16O2-4 and 34S16O2-4, respectively. The Chinese herbal medicines was treated using microwave digestion added 6 mL nitric acid and 2 mL hydrogen peroxide before analysis. The amount of nitric acid and hydrogen peroxide were optimized. The method was validated using Chinese herbal standard reference material GBW10020. The sample was treated and detected in six parallel, and the average concentrations obtained using the developed method (0.42%±0.01%) is in excellent agreement with the standard concentration (0.41%±0.03%). The study demonstrates an accurate and convenient approach for the quantification of SO2 in Chinese herbal medicines.
2016 Vol. 36 (02): 527-531 [Abstract] ( 449 ) PDF (2487 KB)  ( 204 )
532 Multivariate Calibration Combined with Mass Spectrometry for Rapid Analysis
LI Qian-qian1,2, TIAN Kuang-da2, TANG Guo2, XIONG Yan-mei2, MIN Shun-geng2*
DOI: 10.3964/j.issn.1000-0593(2016)02-0532-05
A mixture of four substances of benzaldehyde, iso-octane, butyl acetate, acetophenone were quantitatively analyzed by mass spectrometry combined with chemometrics.The mass chromatogram data of mixture were proceeded with two methods for quantitative analysis. One is feature selection-Multiple Linear Regression (MLR) and the other is full spectrum- Partial Least Squares (PLS). The results show that the RMSEP of benzaldehyde were 0.062 and 0.091 after selecting m/z spectrum and full spectrum respectively; RMSEP of isooctane were 0.048 and 0.057 after selecting spectrum and full spectrum respectively; which of butyl acetate were 0.021 and 0.020 and of acetophenone were 0.010 and 0.032. The feature selection results of the mixture were better than that of the full spectrum modeling results expect butyl acetate which got similar results by the two methods.
2016 Vol. 36 (02): 532-536 [Abstract] ( 378 ) PDF (2166 KB)  ( 189 )
537 Laser Induced Fluorescence Spectrum Characteristics of Paddy under Nitrogen Stress
YANG Jian1, SHI Shuo1, 2, 3*, GONG Wei1, 2, DU Lin1, 4, ZHU Bo1, MA Ying-ying1, 2, SUN Jia1
DOI: 10.3964/j.issn.1000-0593(2016)02-0537-04
Order toguide fertilizing andreduce waste of resources as well as enviro nmental pollution, especially eutrophication, which are caused by excessive fertilization, a system of laser-induced fluorescence(LIF) was built. The system aimed to investigate the correlation between nitrogen(N) content of paddy leaf and the fluorescence intensity. We measuredNcontent and SPAD of paddy leaf (the samples came from the second upper leaves of paddy in tillering stage and the study area was located in Jianghan plain of China) by utilizing the Plant Nutrient (Tester TYS-3N). The fluorescence spectrum was also obtained by using the systembuilt based on theLIFtechnology. Fluorescence spectra of leaf with different N-content were collected and then a fluorescence spectra database wasestablished.It is analyzed that the relationship between the parameters of fluorescence (F740/F685 is the ratio of fluorescence intensity of 740 nm dividing that of 685 nm) and the N level of paddy. It is found that the effect of different N-content on the fluorescence spectrum characteristics is significant. The experiment demonstrated the positive correlation between fluorescence parameters and paddy leaf N-content. Results showed a positive linear correlation between the ratio of peak fluorescence (F740/F685) and N-content. The correlation coefficient (r) reached 0.871 8 and the root mean square error (RMSE) was 0.076 82. The experiment demonstrated that LIF spectroscopy detection technology has the advantages of rapidand non-destructive measurement, and it also has the potential to measure plant content of nutrient elements. It will provide a more accurate remote sensing method to rapidly detect the crop nitrogen levels.
2016 Vol. 36 (02): 537-540 [Abstract] ( 370 ) PDF (1198 KB)  ( 139 )
541 Determination of Carbaryl in Rice by Using FT Far-IR and THz-TDS Techniques
SUN Tong, ZHANG Zhuo-yong*, XIANG Yu-hong, ZHU Ruo-hua
DOI: 10.3964/j.issn.1000-0593(2016)02-0541-04
Determination of carbaryl in rice by using Fourier transform far-infrared (FT- Far-IR) and terahertz time-domain spectroscopy (THz-TDS) combined with chemometrics was studied and the spectral characteristics of carbaryl in terahertz region was investigated. Samples were prepared by mixing carbaryl at different amounts with rice powder, and then a 13 mm diameter, and about 1 mm thick pellet with polyethylene (PE) as matrix was compressed under the pressure of 5~7 tons. Terahertz time domain spectra of the pellets were measured at 0.5~1.5 THz, and the absorption spectra at 1.8~6.3 THz were acquired with Fourier transform far-IR spectroscopy. The method of sample preparation is so simple that it does not need separation and enrichment. The absorption peaks in the frequency range of 1.8~6.3 THz have been found at 3.2 and 5.2 THz by Far-IR. There are several weak absorption peaks in the range of 0.5~1.5 THz by THz-TDS. These two kinds of characteristic absorption spectra were randomly divided into calibration set and prediction set by leave-N-out cross-validation, respectively. Finally, the partial least squares regression (PLSR) method was used to establish two quantitative analysis models. The root mean square error (RMSECV), the root mean square errors of prediction (RMSEP) and the correlation coefficient of the prediction are used as a basis for the model of performance evaluation. For the Rv, a higher value is better; for the RMSEC and RMSEP, lower is better. The obtained results demonstrated that the predictive accuracy of the two models with PLSR method were satisfactory. For the FT-Far-IR model, the correlation between actual and predicted values of prediction samples (Rv) was 0.99. The root mean square error of prediction set (RMSEP) was 0.008 6, and for calibration set (RMSECV) was 0.007 7. For the THz-TDS model, Rv was 0.98, RMSEP was 0.004 4, and RMSECV was 0.002 5. Results proved that the technology of FT-Far-IR and THz-TDS can be a feasible tool for quantitative determination of carbaryl in rice. This paper provides a new method for the quantitative determination pesticide in other grain samples.
2016 Vol. 36 (02): 541-544 [Abstract] ( 343 ) PDF (1434 KB)  ( 145 )
545 Accuracy Improvement of Temperature Calculation of the Laser-Induced Plasma Using Wavelet Transform Baseline Subtraction
LIU Li, XIAO Ping-ping
DOI: 10.3964/j.issn.1000-0593(2016)02-0545-05
Temperature is one of the most important parameters in studying of laser-induced plasma characteristics. To reduce the impact of continuous background on the calculation of temperatures using Boltzmann plots, the wavelet transform was used to decompose the spectrums, and the low-frequency signals represented the spectral baseline were deducted by using soft-threshold method. Selecting the appropriate wavelet decomposition level L and threshold coefficient α can increase the linear regression coefficient R2 of Boltzmann plots, and the calculation accuracy of plasma temperature was improved. The LIBS spectra of low alloy steel sample region from 417 to 445 nm were decomposed by using db4 wavelet, and then baseline subtraction and signal reconstruction were carried out, respectively. Twelve Fe atomic lines were chosen to establish Boltzmann plots, and the temperatures were calculated from the slope of the fitted lines in the plots. The value L and α were optimized according R2, the results showed that the 8-layer db4 wavelet decomposition can gain the high R2, while the value of α associated with the delay time td, e. g., the optimum α corresponding to maximum values of R2 is 0.3 when td≤4.0 μs, and then decrease with the increasing of td, and reduced to 0 when td≥6.0 μs. The interference due to baseline on the spectral characteristic lines gradually reduced with the increasing of td, and therefore α decreased with td increase. After the baseline was deducted, the temperature calculated by Boltzmann plot decrease of about 2 000 to 3 000 K. The temperature gradually decreased with the increasing of the td, and the temperature fluctuation is reduced after baseline subtraction, these results are consistent with the physical process of plasma expansion.
2016 Vol. 36 (02): 545-549 [Abstract] ( 422 ) PDF (2411 KB)  ( 544 )
550 The X-Ray Fluorescence Spectrometer Based on Pyroelectric Effect
DONG Yi-fan1, 2, FAN Rui-rui1, GUO Dong-ya1, 2, ZHANG Chun-lei1, GAO Min1, WANG Jin-zhou1, LIU Ya-qing1, ZHOU Da-wei1, 2, WANG Huan-yu1
DOI: 10.3964/j.issn.1000-0593(2016)02-0550-05
Pyroelectric X-ray generator is implemented, and an X-ray fluorescence spectrometer is accomplished by combining the pyroelectric X-ray generator with a high energy resolution silicon drift detector. Firstly, the parameters of the X-ray generator are decided by analyzing and calculating the influence of the thickness of the pyroelectriccrystal and the thickness of the target on emitted X-ray. Secondly, the emitted X-ray is measured. The energy of emitted X-ray is from 1 to 27 keV, containing the characteristic X-ray of Cu and Ta, and the max counting rate is more than 3 000 per second. The measurement also proves that the detector of the spectrometer has a high energy resolution which the FWMH is 210 eV at 8.05 keV. Lastly, samples of Fe, Ti, Cr and high-Ti basalt are analyzed using the spectrometer, and the results are agreed with the elements of the samples. It shows that the spectrometer consisting of a pyroelectric X-ray generator and a silicon drift detector is effective for element analysis.Additionally, because each part of the spectrometer has a small volume, it can be easily modified to a portable one which is suitable for non-destructive, on-site and quick element analysis.
2016 Vol. 36 (02): 550-554 [Abstract] ( 379 ) PDF (2201 KB)  ( 184 )
555 Analysis and Correction of Spectral Curvature in Hadamard Transform Spectrometer with DMD
QUAN Xiang-qian1,2, LIU Hua1*, LU Zhen-wu1, WANG Xiao-duo1,2, DANG Bo-shi1, CHEN Xiang-zi1,2, WANG Fang1
DOI: 10.3964/j.issn.1000-0593(2016)02-0555-06
Due to the advantages of its low cost and high utilization rate of light energy and no moving parts,Hadamard transform spectrometer with DMD has become a focus in the research of spectrometer. In order to solve the reduction of spectral resolution caused by the spectral curvature of Hadamard transform spectrometer with DMD (Digital Micro-mirror Device), the spectral aliasing in the spectrometer was investigated. Firstly, the mathematical relationship of spectral aliasing to radius of spectral curvature was deduced. Then, two procedures were proposed to solve the spectral aliasing. One is making the DMD encoded spectral band accordant with the standard spectral band as far as possible by adjusting the DMD-encoded stripe,and another is correcting remaining spectral aliasing by means of data processing. Finally,by analyzing and correcting spectral curvature in six situations of the curvature radius of 15.8×104,7.8×104,9.7×104 μm and etc,we fit out the relationship of spectral aliasing and spectrum correction effect of spectral curvature to the curvature radius. The simulation indicates that the spectral resolution increases to the resolution of optical system. It shows that the proposed methods are universal, simple and effective in the improvement of spectral resolution.
2016 Vol. 36 (02): 555-560 [Abstract] ( 359 ) PDF (2797 KB)  ( 218 )
561 The Research on Measurement System and Method of Tissue Optical Parameters with Wide Spectra Based on Double-Integrating-Spheres
HAN Lei1, LI Chen-xi1, 2*, SUN Cheng-tao1, JIANG Jing-ying1, ZHAO Hui-juan1,2, XU Ke-xin1,2
DOI: 10.3964/j.issn.1000-0593(2016)02-0561-06
The measurement of tissue optical parameters is the focusing research content of Biomedical Photonics. The optical properties of human tissue are closely related to the physiological and pathological state. In recent years, the tissue imaging diagnosis and non-invasive detection of componentsbecome the hot research topics, applying the tissue optical properties especially the absorption and scattering properties. These provide the basis for the study of optical imaging and the spectrum detection of body composition etc. The Double-Integrating-Spheres (DIS) method can measure the absorption coefficient, scattering coefficient and so on in vitro tissuesimultaneously. It has the advantages of accurate, rapid, large applicable scope. The method applya standard method for measuring the optical parameters. This paper build the wide spectrum measurement system of optical parameters based on DIS and super continuum lasers. Then we analyze the transfer function, error sources and the best measuring conditions of the system. Finally we establish the correction forward model based on BP-MCML and the inverse algorithm of the optical parameters based on L-M algorithm. The optical parameters of intralipid solution in the wavelength range of 1 100~1 400 nm are measured. The experiment results show that the improved inverse algorithm is accurate. The multiple measurements standard deviation is within 3%. Compared the results of scattering coefficient and absorption coefficient at different wavelengths to the results of other research groups, the deviation is less than 3.4%.
2016 Vol. 36 (02): 561-566 [Abstract] ( 378 ) PDF (2517 KB)  ( 185 )
567 The Preparation and Properties Study of Micellar Thiacalixarenes Self-Assembled Fluorescent Chemosensor
HU Xiao-jun, ZHANG Zhi
DOI: 10.3964/j.issn.1000-0593(2016)02-0567-04
A novel ON-OFF micelle-based fluorescent chemosensor for Cu2+ ions was prepared through the micellar self-assembling in water solutions with p-tert-butylthiacalix[4]arene (TCA) as receptor, perylene as fluorophore and Sodium dodecylbenzenesulphonate (SDBS) as self-assembling template. Several effecting factors, such as the quantities of the receptor TCA, the concentrations of the self-assembling template SDBS, the concentrations of the Cu2+ ions and the co-current metal ions, were investigated for the systematical investigation on the detecting capabilities of the micelle-based fluorescent chemosensor for Cu2+ ions through measuring the quenching of the fluorescent emission of the fluorophore. As the results indicated, when the molar concentration ratio value of the receptor TCA to the fluorophore was equal to 1 000 and the concentrations of the self-assembling template SDBS reached 50 mmol·L-1, the Cu2+ ions could be detected preferably by the prepared micelle-based fluorescent chemosensor. The concentrations of the Cu2+ ions could be almost linearly measured according to the quenching ratios of the fluorescent emission in a certain range of concentration. Furthermore, the detecting capabilities of the micelle-based fluorescent chemosensor for the Cu2+ ions were almost not influenced by the co-existing metal ions such as Pb2+,Cd2+,Mn2+,Na+,K+,Ca2+,Mg2+,Al3+,Ni2+ and Zn2+ ions. The selective detecting capabilities of the obtained micelle-based fluorescent chemosensor for the Cu2+ ions could be mainly attributed to the recognition of the receptor TCA in the surfactant micelle with the Cu2+ ions, and the quenching of the fluorescent emission of the fluorophore was estimated to be based on an intramicellar electron-transfer or energy-transfer mechanism.
2016 Vol. 36 (02): 567-570 [Abstract] ( 379 ) PDF (1345 KB)  ( 126 )
571 Brand-New Ge20Ga5Sb10S65 Prism Biosensor Based on Inverted SPR
LI Wen-chao2, MENG Xiao-yun1, PIAO Rui-qi1, ZHAO Jing-jing1, LI Zhi-quan1*, TONG Kai1, GU Er-dan1
DOI: 10.3964/j.issn.1000-0593(2016)02-0571-06
Based on inverted surface plasmon resonance (ISPR) a novel biosensor consisting of Ge20Ga5Sb10S65-palladium-graphene layer-biomolecule layer is proposed. The refractive index of biomolecule layer alters as biomolecule experience interactions, thus leading to a shift of ISPR angle. On this basis, the spectrum output of sensor is derived by transfer matrix method. The sensitivity, the resolution, the dynamic detection range and the signal to noise ratio of the presented sensor are discussed and compared with the performance of traditional sensors. Moreover, the influences of grapheme layer thickness on sensors are analyzed with comparative study. Finally, near infrared is used as the incident light of the presented sensor. The results show that, the best thickness of grapheme layer is monolayer; the peak intensity of the ISPR reflection is about 80%~90% of intensity of incident light, guaranteeing a high signal to noise ratio; In the visible light, when λ=632.8 nm, the presented sensor is 1.9 times the resolution of the sensor based on SiO2 coupling inverted surface plasmon resonance, is 3.5 times the resolution of the sensor based on surface plasmon resonance(SPR), and is 2 times the dynamic detection range of pre-existing biosensor based on SPR. The application of Ge20Ga5Sb10S65 prism extends the detection light wavelength from the visible region to the near infrared region. When λ=1 000 nm, the sensor is 3~4 times of the sensor in visible region. The research greatly contributes to the realization and application of biosensor based on inverted surface plasmon resonance.
2016 Vol. 36 (02): 571-576 [Abstract] ( 394 ) PDF (3202 KB)  ( 174 )
577 An Extraction and Recognition Method of the Distributed Optical Fiber Vibration Signal Based on EMD-AWPP and HOSA-SVM Algorithm
ZHANG Yan-jun1, 2, LIU Wen-zhe1, FU Xing-hu1, 2*, BI Wei-hong1, 2
DOI: 10.3964/j.issn.1000-0593(2016)02-0577-06
Given that the traditional signal processing methods can not effectively distinguish the different vibration intrusion signal, a feature extraction and recognition method of the vibration information is proposed based on EMD-AWPP and HOSA-SVM, using for high precision signal recognition of distributed fiber optic intrusion detection system. When dealing with different types of vibration, the method firstly utilizes the adaptive wavelet processing algorithm based on empirical mode decomposition effect to reduce the abnormal value influence of sensing signal and improve the accuracy of signal feature extraction. Not only the low frequency part of the signal is decomposed, but also the high frequency part the details of the signal disposed better by time-frequency localization process. Secondly, it uses the bispectrum and bicoherence spectrum to accurately extract the feature vector which contains different types of intrusion vibration. Finally, based on the BPNN reference model, the recognition parameters of SVM after the implementation of the particle swarm optimization can distinguish signals of different intrusion vibration, which endows the identification model stronger adaptive and self-learning ability. It overcomes the shortcomings, such as easy to fall into local optimum. The simulation experiment results showed that this new method can effectively extract the feature vector of sensing information, eliminate the influence of random noise and reduce the effects of outliers for different types of invasion source. The predicted category identifies with the output category and the accurate rate of vibration identification can reach above 95%. So it is better than BPNN recognition algorithm and improves the accuracy of the information analysis effectively.
2016 Vol. 36 (02): 577-582 [Abstract] ( 426 ) PDF (2931 KB)  ( 273 )
583 Determination of Poly(Diallyldimethylammonium Chloride) via Spectrophotometric Titration with Coomassie Brilliant Blue G Dye
Alexander Shyichuk*, Dorota Ziókowska, Jan Lamkiewicz
DOI: 10.3964/j.issn.1000-0593(2016)02-0583-05
Poly(diallyldimethylammonium chloride) (PDDA) is used as organic coagulant in water purification and auxiliary agent in paper production. Determination of PDDA in aqueous solutions is carried out usually by means of polyelectrolyte titration using streaming current detector or o-Toluidine Blue dye for endpoint recognition. The proposed method of PDDA assay takes advantage of Coomassie Brilliant Blue G dye having strong affinity to cationic macromolecules. Titration of PDDA solution with the dye is carried out measuring absorbance at 585 nm. Inflection points of the obtained zigzag photometric curves have good repeatability provided that titration rate is low enough to attain endpoint for 1 hour or more. The method assures rectilinear calibration (R2=0.999 5) in the broad range of PDDA concentrations from 0.3 to 9.6 mg·dm-3.
2016 Vol. 36 (02): 583-587 [Abstract] ( 315 ) PDF (3503 KB)  ( 174 )
588 Examination of Correlation between Histidine and Cadmium Absorption by Eleagnus angustifolia L., Vitisvinifera L. and Nerium oleander L. Using HPLC-MS and ICP-MS
Sukran Akkus Ozen, Mehmet Yaman*
DOI: 10.3964/j.issn.1000-0593(2016)02-0588-05
In this study, HPLC-MS and ICP-MS methods wereused for the determination of histidine and cadmiumin Eleagnusangustifolia L., Vitisvinifera L. and Nerium oleander L. leaves taken from industrial area including Gaziantep and Bursa cities. To histidine determination by HPLC-MS, flow rate of mobile phase, fragmentor potential, injection volume and column temperature were optimized as 0.2 mL·min-1, 70 V, 15 μL and 20 ℃, respectively. For extraction of histidine from plants, distilled water was used by applying on 90 ℃ and 30 min. The concentrations (as mg·kg-1) of histidine were found to be in range of 8~22 for Eleagnusangustifolia L., 10~33 for Vitisvinifera L. and 6~11 for Nerium oleander L. The concentrations of cadmium were found to be in ranges of 6~21 μg·kg-1 for Vitisvinifera L. 15~110 μg·kg-1 for Eleagnusangustifolia L. and 63~218 μg·kg-1 for Nerium oleander L.
2016 Vol. 36 (02): 588-592 [Abstract] ( 355 ) PDF (986 KB)  ( 171 )
593 The Characteristic Spectral Selection Method Based on Forward and Backward Interval Partial Least Squares
QU Fang-fang1, REN Dong1*, HOU Jin-jian1,2, ZHANG Zhong1, LU An-xiang2, WANG Ji-hua1,2, XU Hong-lei3
DOI: 10.3964/j.issn.1000-0593(2016)02-0593-06
In the near-infrared spectroscopy, the Forward Interval Partial Least Squares (FiPLS) and Backward Interval Partial Least Squares (BiPLS) are commonly used modeling methods, which are based on the wavelength variable selection. These methods are usually of high prediction accuracy, but are strongly characteristic of greedy search, which causes that the intervals selected are not good enough to indicate the analyte information. To solve the problem, a spectral characteristic intervals selection strategy (FB-iPLS) based on the combination of FiPLS and BiPLS is proposed. On the basis of spectral segmentation, both FiPLSs are used to select useful intervals, and BiPLS is used to delete useless intervals, so as to perform the selection and deletion of the characteristic variables alternatively, which conducts a two-way choice of the target characteristic variables, and is used to improve the robustness of the model. The experiments on determining the ethanol concentration in pure water are conducted by modeling with FiPLS, BiPLS and the proposed method. Since different size of intervals will affect the result of the model, the experiments here will also examine the model results with different intervals of these three models. When the spectrum is divided into 60 segments, the FB-iPLS method obtains the best prediction performance. The correlation coefficients (r) of the calibration set and validation set are 0.967 7 and 0.967 0 respectively, and the cross-validation root mean square errors (RMSECV) are 0.088 8 and 0.057 1, respectively. Compared with FiPLS and BiPLS, the overall prediction performance of the proposed model is better. The experiments show that the proposed method can further improve the predictive performance of the model by resolving the greedy search feature against BiPLS and FiPLS, which is more efficient for and representative of the selection of characteristic intervals.
2016 Vol. 36 (02): 593-598 [Abstract] ( 365 ) PDF (1667 KB)  ( 195 )
599 Research on Ground-Based LWIR Hyperspectral Imaging Remote Gas Detection
ZHENG Wei-jian1,2, LEI Zheng-gang1, YU Chun-chao1, YANG Zhi-xiong1, WANG Hai-yang1,2, FU Yan-peng1,2, LI Xun-niu1,2, LIAO Ning-fang2, SU Jun-hong1,2
DOI: 10.3964/j.issn.1000-0593(2016)02-0599-08
The new progress of ground-based long-wave infrared remote sensing is presented, which describes the windowing spatial and temporal modulation Fourier spectroscopy imaging in details. The prototype forms the interference fringes based on the corner-cube of spatial modulation of Michelson interferometer, using cooled long-wave infrared photovoltaic staring FPA (focal plane array) detector. The LWIR hyperspectral imaging is achieved by the process of collection, reorganization, correction, apodization, FFT etc. from data cube. Noise equivalent spectral radiance (NESR), which is the sensitivity index of CHIPED-1 LWIR hyperspectral imaging prototype, can reach 5.6×10-8 W·(cm-1·sr·cm2)-1 at single sampling. The data is the same as commercial temporal modulation hyperspectral imaging spectrometer. It can prove the advantage of this technique. This technique still has space to be improved. For instance, spectral response range of CHIPED-1 LWIR hyperspectral imaging prototype can reach 11.5 μm by testing the transmission curve of polypropylene film. In this article, choosing the results of outdoor high-rise and diethyl ether gas experiment as an example, the authors research on the detecting method of 2D distribution chemical gas VOC by infrared hyperspectral imaging. There is no observed diethyl ether gas from the infrared spectral slice of the same wave number in complicated background and low concentration. By doing the difference spectrum, the authors can see the space distribution of diethyl ether gas clearly. Hyperspectral imaging is used in the field of organic gas VOC infrared detection. Relative to wide band infrared imaging, it has some advantages. Such as, it has high sensitivity, the strong anti-interference ability, identify the variety, and so on.
2016 Vol. 36 (02): 599-606 [Abstract] ( 402 ) PDF (4361 KB)  ( 179 )