Journals >Spectroscopy and Spectral Analysis
Contents
2014
Volume: 34 Issue 6
58 Article(s)
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Research Article
Study on Packaging-Induced Stress in 4 mm Cavity Length High-Power Single Emitter Semiconductor Laser
ZHANG Yong, YANG Rui-xia, AN Zhen-feng, LIU Xiao-wen, and XU Hui-wu
To reduce packaging-induced stress of long cavity length high-power single emitter semiconductor laser, the relationship between the stress and the wavelength shift was deduced on the basis of the theory that the stress can change the band gap. A method was developed for quantitatively calculating the stress by measuriTo reduce packaging-induced stress of long cavity length high-power single emitter semiconductor laser, the relationship between the stress and the wavelength shift was deduced on the basis of the theory that the stress can change the band gap. A method was developed for quantitatively calculating the stress by measuring the emission spectrum of the laser under pulse conditions. The results show that the soldering quality is a critical factor affecting thermal stress. The difference in stress can exceed 300 MPa due to the difference in soldering quality. By optimizing the reflowing soldering curve of the laser, the stress of the laser drops from 129.7 to 53.4 MPa. This method can also effectively solve the problem that the stress varies with storage time. This work demonstrates that the measurement and analysis of the emission spectrum of the laser can provide a useful method to study packaging stress of the high-power single emitter semiconductor laser. It is also an available means to evaluate and analyze soldering quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1441 (2014)
System of ns Time-Resolved Spectroscopy Diagnosis and Radioprotection
YAO Wei-bo, GUO Jian-ming, ZHANG Yong-min, TANG Jun-ping, CHENG Liang, and XU Qi-fu
Cathode plasma of high current electron beam diode is an important research on high power microwave and strong pulsed radio accelerator. It is a reliable method to study cathode plasma by diagnosing the cathode plasma parameters with non-contact spectroscopy measurement system. The present paper introduced the work priCathode plasma of high current electron beam diode is an important research on high power microwave and strong pulsed radio accelerator. It is a reliable method to study cathode plasma by diagnosing the cathode plasma parameters with non-contact spectroscopy measurement system. The present paper introduced the work principle, system composition and performance of the nanosecond (ns) time-resolved spectroscopy diagnosis system. Furthermore, it introduced the implementing method and the temporal relation of lower jitter synchronous trigger system. Simultaneously, the authors designed electromagnetic and radio shield room to protect the diagnosis system due to the high electromagnetic and high X-ray and γ-ray radiation, which seriously interferes with the system. Time-resolved spectroscopy experiment on brass (H62) cathode shows that, the element and matter composition of cathode plasma is clearly increase with the increase in the diode pulsed voltage and current magnitude. The spectroscopy diagnosis system could be of up to 10 ns time resolve capability. It’s least is 2 ns. Synchronous trigger system’s jitter is less than 4 ns. The spectroscopy diagnosis system will open a new way to study the cathode emission mechanism in depth..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1446 (2014)
Laser and Vision Measurement Research on Parameters of Miniature Quartz Plate-Sensitive Glass Part
WANG Xin, and ZHANG Xiao-dong
High-precision, rapid and non-contact geometry parameter measurements of plate glass parts has become a main problem in the field of testing-related production and processing and also an important applied direction for laser spectroscopy. Accurately detect the geometric parameters of plate glass parts can not only imprHigh-precision, rapid and non-contact geometry parameter measurements of plate glass parts has become a main problem in the field of testing-related production and processing and also an important applied direction for laser spectroscopy. Accurately detect the geometric parameters of plate glass parts can not only improve the processing technology and the precision of assembly, but also bring about sub-file management according to the parameters. This paper presents a novel multi-parameter measurement method based on the laser and vision image processing technology, which can be used to measure parameters of miniature quartz plate-sensitive glass part accurately. The testing system consisting of self-adaption coaxial visual detection unit and laser vision thickness inspection unit was designed. A constant power drive control system was set up to ensure the laser diode (LD) can provide a stable light source for the testing system. A modified sub-pixel edge position algorithm of conic features was proposed to implement the sub-pixel image processing, and the parameters can be extracted. According to the data detected from curve edge points and a new-defined error function, which was minimized, the parameters of miniature quartz plate-sensitive glass part can be calculated. The experiments show that the average deviation of the measurement results is less than 2 μm, and the method has good stability and high accuracy measurement, which can meet the precision requirement of parameter measurement for miniature plate glass part..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1450 (2014)
Study on Phase-Matching of Four-Wave Mixing Spectrum in Photonic Crystal Fiber
LIU Xiao-xu, WANG Shu-tao, ZHAO Xing-tao, CHEN Shuang, ZHOU Gui-yao, WU Xi-jun, LI Shu-guang, and HOU Lan-tian
In the present paper, the four-wave mixing principle of fiber was analyzed, and the high-gain phase-matching conditions were shown. The nonlinear coefficient and dispersion characteristics of photonic crystal fibers were calculated by multipole method. The phase mismatch characteristics of fibers with multiple zero-disIn the present paper, the four-wave mixing principle of fiber was analyzed, and the high-gain phase-matching conditions were shown. The nonlinear coefficient and dispersion characteristics of photonic crystal fibers were calculated by multipole method. The phase mismatch characteristics of fibers with multiple zero-dispersion wavelengths were analyzed for the first time. The changing rules of phase matching wavelength with the pump wavelength and the pump power were obtained, and the phase matching curves were shown. The characteristics of phase matching wavelengths for different dispersion curves were analyzed. There are four new excitation wavelengths of four-wave mixing spectrum in two zero-dispersion wavelength photonic crystal fibers. Four-wave mixing spectroscopy of photonic crystal fibers with two zero-dispersion wavelengths was obtained in the experiment, which is consistent with the theoretical analysis, and verified the reliability of the phase matching theory. The fiber with multiple zero-dispersion wavelengths can create a rich phase-matching topology, excite more four-wave mixing wavelengths, enabling enhanced control over the spectral locations of the four-wave mixing and resonant-radiation bands emitted by solitons and short pulses. These provide theoretical guidance for photonic crystal fiber wavelength conversion and supercontinuum generation based on four-wave mixing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1460 (2014)
Spectral Characteristics and Implication of Granite from Pozaiying Molybdenite Deposits in West of Guangdong
AN Yan-fei, ZHONG Li-li, ZHOU Yong-zhang, CHEN Qing, and LI Xing-yuan
Some granite samples from Pozaiying molybdenite deposits in the west of Guangdong were retrieved to characterize the spectral signature of XRD, FT-NIR and Raman. The results show that compared to the Porphyry granite and granite in the far zone, the signal of XRD and Raman of granite in near zone is weaker while the siSome granite samples from Pozaiying molybdenite deposits in the west of Guangdong were retrieved to characterize the spectral signature of XRD, FT-NIR and Raman. The results show that compared to the Porphyry granite and granite in the far zone, the signal of XRD and Raman of granite in near zone is weaker while the signal of FT-NIR is stronger. The authors’ analyses indicate that the FWHM of quartz (101) peak in XRD, Sericite peak (4 529 cm-1) in FT-NIR and quartz peak in Raman shift from the latter are higher than those of former two. Those spectral characteristics indicate that compared with other samples, the content of petrogenetic mineral in samples from near zone is lower while the content of alteration mineral is higher, and its crystallinity and crystallization temperatures are both lower. The authors’ studies suggest that there may be an alteration zone, embracing the granite-porphyry, which comprised low temperature mineral. and the quartz-porphyry which related to molybdenite mineralization belongs to the zone near Guanshanzhang mass..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1465 (2014)
Investigation of a Jet Operated in Atmospheric Pressure Argon by Optical Emission Spectroscopy
LI Xue-chen, BAO Wen-ting, JIA Peng-ying, DI Cong, and YUAN Ning
A uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequencA uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequency and the gas flow rate. It was found that with increasing the gas flow rate, the plume length increases when the flow rate is lower than 4 L·min-1, and decreases when it is higher than 4 L·min-1. Under constant gas flow rate, the length of the plasma plume increases with the increase in the peak value of the applied voltage and the driving frequency. According to the discharge theory and based on the analysis of the turbulence and the advection, a qualitative explanation was given for the variance of plume length as functions of the experimental parameters. Results also show that there is a discharge pulse for the plasma plume in every positive half cycle, while there is no pulse in negative half cycle. The coaxial dielectric barrier discharge shows two pulses in every positive half cycle and a pulse in every negative half cycle. Analyzing these experimental phenomena mentioned above, a formation mechanism of the plasma plume was proposed. The optical emission spectra were obtained for both the coaxial dielectric barrier discharge and the plasma plume. There was no apparent difference except that some emission lines from reactive species such as OH and N2 were found in the plasma plume. Using the first negative band of, the rational temperature of the plasma plume was measured. Results show that the rational temperature of the plasma plume decreases away from the jet nozzle, and increases with increasing the peak value of the applied voltage..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1469 (2014)
Discussion of Scattering in THz Time Domain Spectrum Tests
YAN Fang, ZHANG Zhao-hui, ZHAO Xiao-yan, SU Hai-xia, LI Zhi, and ZHANG Han
Using THz-TDS to extract the absorption spectrum of a sample is an important branch of various THz applications. Basically, we believe that the THz radiation scatters from sample particles, leading to an obvious baseline increasing with frequencies in its absorption spectrum. The baseline will affect the measurement acUsing THz-TDS to extract the absorption spectrum of a sample is an important branch of various THz applications. Basically, we believe that the THz radiation scatters from sample particles, leading to an obvious baseline increasing with frequencies in its absorption spectrum. The baseline will affect the measurement accuracy due to ambiguous height and pattern of the spectrum. The authors should try to remove the baseline, and eliminate the effects of scattering. In the present paper, we investigated the causes of baselines, reviewed some of scatter mitigating methods and summarized some of research aspects in the future. In order to validate the correctness of these methods, we designed a series of experiments to compare the computational accuracy of molar concentration. The result indicated that the computational accuracy of molar concentration can be improved, which can be the basis of quantitative analysis in further researches. Finally, with comprehensive experimental results, we presented further research directions on THz absorption spectrum that is needed for the removal of scattering effects..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1473 (2014)
Gold Nanoparticles-Based Localized Surface Plasmon Resonance Scattering Analysis Method for the Determination of Trace Amounts of Hg(Ⅱ)
Heavy-metal ions pose severe risks for human health and the environment. In particular, mercury-based pollutants are of great environmental concern because of the high toxicity of many Hg compounds. It is important to monitor the levels of potentially toxic metal Hg(Ⅱ) in aquatic ecosystems. Gold nanoparticles (AuNPs) Heavy-metal ions pose severe risks for human health and the environment. In particular, mercury-based pollutants are of great environmental concern because of the high toxicity of many Hg compounds. It is important to monitor the levels of potentially toxic metal Hg(Ⅱ) in aquatic ecosystems. Gold nanoparticles (AuNPs) as nanomaterials have been generally studied. It is because their unique electrical, chemical, optical, and catalytic properties, AuNPs have caused widespread interest for applications in biological and chemical analysis and detection. In the present work, the authors took advantage of the aggregation-induced localized surface plasmon resonance (LSPR) light scattering signal change of sodium thioglycolate functionalized AuNPs in aqueous solutions to develop a highly efficient optical sensor for Hg(Ⅱ). The as-modified AuNPs demonstrate that high negative charge densities exist on their surfaces at pH 9.0 Britton-Robinson (BR) buffer solution. The AuNPs occur aggregate in solution through chelation in the presence of Hg(Ⅱ). The scanning electron microscope (SEM) images for the AuNPs display typical shapes of these AuNPs as regular and almost individual spherical particles. The color change of the AuNPs solution was induced by the addition of Hg(Ⅱ) and it immediately changed from red to purple due to the aggregation. Under optimum conditions, a good linear relationship was obtained from 0.08 to 0.8 μmol·L-1 with a correlation coefficient of 0.997 6, and the limit of detection (LOD) was 8.0 nmol·L-1. PEG20000 was employed as a system stabilizer. The proposed method has an excellent selectivity for Hg(Ⅱ) in aqueous medium over other metal ions. The optimum test of reaction conditions, including the amount of AuNPs, pH value, reaction stability and ionic strength, were also investigated. This method has been used for determination of Hg(Ⅱ) successfully in environmental water sample. This approach manifested several advantages including short analysis time, high sensitivity, low cost, excellent selectivity and ease of operation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1477 (2014)
Photo-Stimulated and Long Persistent Luminescence Properties of Sr3SiO5∶Eu2+, RE3+(RE=Nd3+, Ho3+, La3+)
ZHANG Zhe, XU Xu-hui, QIU Jian-bei, ZHANG Xin, and YU Xue
A series of electron capture materials Sr3SiO5∶Eu2+, RE3+(RE=Nd3+, Ho3+, La3+) were prepared by high temperature solid state method. The photo-stimulated luminescence (PSL) and long afterglow performance were evaluated. After excited by UV light, it showed a strong up-conversion photo-stimulated read-out response when A series of electron capture materials Sr3SiO5∶Eu2+, RE3+(RE=Nd3+, Ho3+, La3+) were prepared by high temperature solid state method. The photo-stimulated luminescence (PSL) and long afterglow performance were evaluated. After excited by UV light, it showed a strong up-conversion photo-stimulated read-out response when stimulated by 980 nm laser, which is attributed to the existence of deep traps (438 K). This property was especially shown in Sr3SiO5∶Eu2+, La3+and Sr3SiO5∶Eu2+, Ho3+. Subsequently, the trapping depth and carrier concentration were studied. In this way, we verified the cause of PSL. The calculation of parameters of trapping electron in the thermoluminescence spectrum is through the method of Chens half width, getting the value of trapping depth under the temperature of 438 K, which contrasts to the energy of 980 nm laser radiation. At the same time, the afterglow performance after co-doping with rare earth ion was greatly improved. The afterglow time of Sr3SiO5∶Eu2+, La3+is up to 12 hours. Research results show that the change in mixed trap structure is the primary cause of photo-stimulated and long persistent luminescence properties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1486 (2014)
Vibrational and Rotational Excitation of CO2 in the Collisional Quenching of H2 (ｖ=1)
ZHANG Wen-jun, FENG Li, LI Jia-ling, LIU Jing, DAI Kang, and SHEN Yi-fan
Energy transfer in H2(1,1)+CO2 collisions was investigated using high resolution transient laser spectroscopy. Rotational state selective excitation of ν=1 for rotational level J=1 was achieved by stimulated Raman pumping. Energy gain into CO2 resulting from collisions with H2(1,1) was probed using transient absorptionEnergy transfer in H2(1,1)+CO2 collisions was investigated using high resolution transient laser spectroscopy. Rotational state selective excitation of ν=1 for rotational level J=1 was achieved by stimulated Raman pumping. Energy gain into CO2 resulting from collisions with H2(1,1) was probed using transient absorption techniques, Distributions of nascent CO2 rotational populations in both the ground (0000) state and the vibrationally excited (0001) state were determined from overtone absorption measurements. Translational energy distributions of the recoiling CO2 in individual rovibrational states were determined through measurement of Doppler-broadened transient line shapes. A kinetic model was developed to describe rates for appearance of CO2 states resulting from collisions with H2(1,1). From scanned CARS(coherent anti-stokes raman scattering) the spectral peaks population ratio n0/n1 was obtained, where n0 and n1 represent the number densities of H2 at the levels (0,1) and (1,1), respectively. Using rotational Boltzmann distribution of H2(ν=0) at 300 K, n1 was yielded. Values for rate coefficients were obtained using data for CO2(0000) J=48 to 76 and CO2(0001) J=5 to 33. The rate coefficients derived from appearance of the (0000) state have values of ktr=(3.9±0.8)×10-11 cm3·molecule-1·s-1 for J=48 and ktr=(1.4±0.3)×10-10 cm3·molecule-1·s-1 for J=76, with a monotonic increase for the higher J states. For the (0001) state, values of ktr remain fairly constant at ktr=(4.3±0.9)×10-12 cm3·molecule-1·s-1. Rotational populations for the nascent CO2 states were measured at 0.5 μs following excitation of H2. The transient population for each state was fit using a Boltzmann rotational distribution. The CO2(0000) J=48～76 rotational states were populated substantially relative to the initial 300 K CO2 distributions, and the distribution is described by Trot. The excited (0001) state has Trot=310 K. The center-of-mass translational temperatures for the (0000) state are all much greater than 300 K, with Trel=1 532 K for J=76. In contrast, transient line profiles for the J=5～33 levels of excited (0001) state do not show any broadening above the initial 300 K distributions, indicating that excitation to the (0001) state is not accompanied by translational energy change..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1492 (2014)
Influence of Urea Formaldehyde Resin on Pyrolysis of Biomass: A Modeling Study by TG-FTIR
LI Si-jin, MU Jun, and ZHANG Yu
Pyrolysis is an efficient and recycling way to utilize waste wood-based panels, in which urea-formaldehyde resin (UF) is the main difference between wood-based board and other kinds of biomass. The present paper studied the three main components (cellulose, hemicelluloses, lignin) of poplar wood, in order to effectivelPyrolysis is an efficient and recycling way to utilize waste wood-based panels, in which urea-formaldehyde resin (UF) is the main difference between wood-based board and other kinds of biomass. The present paper studied the three main components (cellulose, hemicelluloses, lignin) of poplar wood, in order to effectively and environmentally utilize or dispose of waste wood-based panels with pyrolysis technique, to study the influence of urea formaldehyde resin on pyrolytic characteristic of wood during the process of the pyrolysis of waste wood-based panels, and to in-depth explore the mechanism of the effect of UF on each component of wood. Innovatively, the weight-loss character and gas evolution rule of the model (made from cellulose, xylan and lignin, based on the chemical components stud of poplar wood), the main components as well as the ones mixed with UF were analyzed by TG-FTIR (thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer). Results indicated that UF promoted the generation of water and carboxylic acid substances during the cellulose pyrolysis process. UF combined with lignin, formed some kind of unstable nitrogenous structure which produced a large amount of NH3, which took part in the low-temperature (200～300 ℃) pyrolysis of lignin, and directly affected the production of pyrolysis products. It can be concluded that during the process of the pyrolysis of waste wood-based panels, lignin was the one that UF mainly impacted among the three main components of wood..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1497 (2014)
The Study of Photo-Elastic Modulator-Based Fourier Transform Spectroscopy
CHEN You-hua, WANG Zhao-ba, WANG Zhi-bin, WANG Yan-chao, LI Yong-shuai, and ZHANG Yu-han
In order to enhance the spectrum resolution of current photo-elastic modulator-based Fourier transform spectrometer, a multi-reflected photo-elastic modulator-based interferometer structure was proposed in the present paper. Through coating reflecting film alternatingly on the photo-elastic crystal and light oblique inIn order to enhance the spectrum resolution of current photo-elastic modulator-based Fourier transform spectrometer, a multi-reflected photo-elastic modulator-based interferometer structure was proposed in the present paper. Through coating reflecting film alternatingly on the photo-elastic crystal and light oblique incidence, and allowing the incident ray to have the multi-reflection in the crystal and exit from the other side of the crystal, the authors increased the light propagation distance in the crystal and enhanced the optical path difference at last. Based on this, the function of interference-spectrum retrieval was established, the optical system matched to the multi-reflected PEM-based interferometer was designed, and finally, the experimental system of multi-reflected PEM-based Fourier transform spectroscopy for telemetry was established. The principle of verification tests by using 671 nm laser and xenon lamp shows that the interferogram was clear and stable, and the feasibility of the principle of the system was verified. The expected result shows that the spectrum resolution of the designed PEM-FTs with multi-reflection achieved 13 cm-1, and its luminous flux just didnt reduce too much, which ensured the SNR. Through spectral inversion of the interference fringes, the technical feasibility of the spectrum system developed was verified. This work established the basic condition of prototype fabrication, radiation precise calibration, spectral calibration and instrument signal-to-noise ratio test and so on..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1502 (2014)
Analysis of the Stability and Adaptability of Near Infrared Spectra Qualitative Analysis Model
CAO Wu, LI Wei-jun, WANG Ping, and ZHANG Li-ping
The stability and adaptability of model of near infrared spectra qualitative analysis were studied. Method of separate modeling can significantly improve the stability and adaptability of model, but its ability of improving adaptability of model is limited. Method of joint modeling can not only improve the adaptabilityThe stability and adaptability of model of near infrared spectra qualitative analysis were studied. Method of separate modeling can significantly improve the stability and adaptability of model, but its ability of improving adaptability of model is limited. Method of joint modeling can not only improve the adaptability of the model, but also the stability of model, at the same time, compared to separate modeling, the method can shorten the modeling time, reduce the modeling workload; extend the term of validity of model, and improve the modeling efficiency. The experiment of model adaptability shows that, the correct recognition rate of separate modeling method is relatively low, which can not meet the requirements of application, and joint modeling method can reach the correct recognition rate of 90%, and significantly enhances the recognition effect. The experiment of model stability shows that, the identification results of model by joint modeling are better than the model by separate modeling, and has good application value..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1506 (2014)
Analysis of Poly-β-Hydroxyalkonates (PHA) During the Enhanced Biological Phosphorus Removal Process Using FTIR Spectroscopy
LI Wei-hua, MAO Qin-yan, LIU Yi-xin, SHENG Guo-ping, YU Han-qing, HUANG Xian-huai, LIU Shao-geng, LING Qi, and YAN Guo-bing
Enhanced biological phosphorus removal (EBPR) is the main phosphorus removal technique for wastewater treatment. During the anaerobic-aerobic alternative process, the activated sludge experienced the anaerobic storage of polyhydroxy-β-alkonates (PHA) and aerobic degradation, corresponding the infrared peak intensity ofEnhanced biological phosphorus removal (EBPR) is the main phosphorus removal technique for wastewater treatment. During the anaerobic-aerobic alternative process, the activated sludge experienced the anaerobic storage of polyhydroxy-β-alkonates (PHA) and aerobic degradation, corresponding the infrared peak intensity of sludge at 1 740 cm-1 increased in the aerobic phase and declined in the anaerobic phase. Compared with PHA standard, this peak was indentified to attribute the carbonyl of PHA. The overlapping peaks of PHA, protein Ⅰ and Ⅱ bands were separated using Gaussian peak fitting method. The infrared peak area ratios of PHA versus protein I had a good relationship with the PHA contents measured by gas chromatography, and the correlation coefficient was 0.873. Thus, the ratio of the peak area of PHA versus protein Ⅰ can be considered as the indicator of the PHA content in the sludge. The infrared spectra of 1 480~1 780 cm-1 was selected, normalized and transferred to the absorption data. Combined with the chromatography analysis of PHA content in the sludge sample, a model between the Fourier-transform infrared spectroscopy (FTIR) spectra of the sludge and PHA content was established, which could be used for the prediction of the PHA content in the unknown sample. The PHA content in the sludge sample could be acquired by the infrared spectra of the sludge sample and the established model, and the values fitted well with the results obtained from chromatograph. The results would provide a novel analysis method for the rapid characterization and quantitative determination of the intracellular PHA content in the activated sludge..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1512 (2014)
Vibrational Spectrum and XPS Contrastive Studies on Pyrochlore-Type Oxygen-Rich Ce2Zr2O8 and Oxygen-Defective Nd2Zr2O2 Phases
XIE Hua, WANG Lie-lin, LUO De-li, and CHEN Min
Pyrochlore-type oxygen-rich Ce2Zr2O8 phase was prepared successfully by graphite reduction method. With the oxygen［U8］-defective Nd2Zr2O7 substituting for the oxidized precursor phase CeZrO3.5+δ was carried out the structure comparative analysis with Ce2Zr2O8. The X-ray diffraction (XRD), Raman spectroscopy (Raman), inPyrochlore-type oxygen-rich Ce2Zr2O8 phase was prepared successfully by graphite reduction method. With the oxygen［U8］-defective Nd2Zr2O7 substituting for the oxidized precursor phase CeZrO3.5+δ was carried out the structure comparative analysis with Ce2Zr2O8. The X-ray diffraction (XRD), Raman spectroscopy (Raman), infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the crystal structure of samples.The XRD experimental results show that Ce2Zr2O8 bulk phase contains the typical structure of pyrochlore, the superstructure peaks that characterize Ce/Zr cations ordering arrangement are very obvious, but the Zr—O ligands had also transformed from octahedrons of the co-top connection in the precursor to cubes of co-edge connection in the Ce2Zr2O8, and the formation of ［ZrO8］ ligand reduced greatlly the structural stability of Ce2Zr2O8 phase. Raman and IR results show that vibrational spectra bands of Ce2Zr2O8 phase increased significantly, meaning that the enriched oxygen ions result in a removal of the degeneracy peak for Ce2Zr2O8 phase, which confirms further the structural symmetry of Ce2Zr2O8 phase lower than its precursor. XPS results show that Ce (Ⅳ) characteristic peak (916.3 eV) in the Ce2Zr2O8 phase surface is very obvious. No the appearance of Ce (Ⅲ) peak (885 eV) suggests that Ce3+ from the precursor has been completely oxidized into Ce4+ in the Ce2Zr2O8 phase; the Zr(3d) binding energy is close to fluorite phase with Zr4+, which confirms that ［ZrO8］ ligand in the Ce2Zr2O8 surface is consistent with the bulk phase. The increasing low binding energy of O(1s) shows that oxygen species in the Ce2Zr2O8 bulk phase are between lattice oxygen and adsorbed oxygen, the presence of high oxygen peak suggests that the surface of Ce2Zr2O8 contains adsorbed oxygen, and the bonding strength between adsorption oxygen and Ce2Zr2O8 bulk phase is between CeO2 and Nd2Zr2O7..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1518 (2014)
Pre-Alarming Apparatus for Earthquake Based on Mid-Infrared Trace Methane Detection
QIU He, LIU Ming-jun, and TIAN Xiao-feng
With the rapid development of gas observation technology in seismic fracture zone, in order to accurately predict the earthquake, and reduce the people’s lives and property losses caused by earthquake, a mid-infrared methane sensor was designed and developed, which is based on the microscopic relation between methane rWith the rapid development of gas observation technology in seismic fracture zone, in order to accurately predict the earthquake, and reduce the people’s lives and property losses caused by earthquake, a mid-infrared methane sensor was designed and developed, which is based on the microscopic relation between methane release and earthquake fissures on the crustal rocks. This instrument utilizes quantum cascaded laser (QCL) operating at 7.65 μm, combined with MIR multipass herriott cell with 76 m absorption path length to obtain low detection sensitivity down to 40 nmol·mol-1 level in 4s acquisition time. Meanwhile, to decrease the primary noise source (1/f noise), semiconductor laser frequency modulation of direct absorption technology was utilized to obtain gas detection limitation as low as 5 nmol·mol-1 (40 s acquiring time). In field experiments, controllable vibrator was used as vibration source, a number of trace methane detectors were placed with 100 m distance interval to carry out the dynamic measurement of methane concentration on the ground surface at different distances from the vibration source. Experimental results show that the instrument can monitor the release of underground methane before the earthquake and provide a novel measure as a pre-alarming for earthquake..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1524 (2014)
Testing of Germination Rate of Hybrid Rice Seeds Based on Near-Infrared Reflectance Spectroscopy
LI Yi-nian, JIANG Dan, LIU Ying-ying, DING Wei-min, DING Qi-shuo, and ZHA Liang-yu
Germination rate of rice seeds was measured according to technical stipulation of germination testing for agricultural crop seeds at present. There existed many faults for this technical stipulation such as long experimental period, more costing and higher professional requirement. A rapid and non-invasive method was pGermination rate of rice seeds was measured according to technical stipulation of germination testing for agricultural crop seeds at present. There existed many faults for this technical stipulation such as long experimental period, more costing and higher professional requirement. A rapid and non-invasive method was put forward to measure the germination rate of hybrid rice seeds based on near-infrared reflectance spectroscopy. Two varieties of hybrid rice seeds were aged artificially at temperature 45 ℃ and humidity 100% condition for 0, 24, 48, 72, 96, 120 and 144 h. Spectral data of 280 samples for 2 varieties of hybrid rice seeds with different aging time were acquired individually by near-infrared spectra analyzer. Spectral data of 280 samples for 2 varieties of hybrid rice seeds were randomly divided into calibration set (168 samples) and prediction set (112 samples). Gormination rate of rice seed with different aging time was tested. Regression model was established by using partial least squares (PLS). The effect of the different spectral bands on the accuracy of models was analyzed and the effect of the different spectral preprocessing methods on the accuracy of models was also compared. Optimal model was achieved under the whole bands and by using standardization and orthogonal signal correction (OSC) preprocessing algorithms with CM2000 software for spectral data of 2 varieties of hybrid rice seeds, the coefficient of determination of the calibration set (RC) and that of the prediction set (RP) were 0.965 and 0.931 individually, standard error of calibration set (SEC) and that of prediction set (SEP) were 1.929 and 2.899 respectively. Relative error between tested value and predicted value for prediction set of rice seeds is below 4.2%. The experimental results show that it is feasible that rice germination rate is detected rapidly and nondestructively by using the near-infrared spectroscopy analysis technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1528 (2014)
Study on Spectral Calibration of Discrimination of Corn Variety Using Near-Infrared Spectra Based on DS Algorithm
LIU Pei-zhong, ZHANG Li-ping, LI Wei-jun, QIN Hong, and DONG Xiao-li
From the perspective of calibration, the present paper studies the model stability problem in qualitative analysis of NIR. Aiming at the issue of model failure caused by different data acquisition time, 13 varieties of corn were used as experimental material, and learning from the idea of model calibration transfer betFrom the perspective of calibration, the present paper studies the model stability problem in qualitative analysis of NIR. Aiming at the issue of model failure caused by different data acquisition time, 13 varieties of corn were used as experimental material, and learning from the idea of model calibration transfer between the two instruments in quantitative analysis of NIR, the DS(direct standardization ) algorithm was used to calibrate the spectra acquired at different times with the same instrument, that made the varieties identification model established one time able to be applied to identify the test data at different acquisition time. First, transfer set was selected from the master spectrum set by Kennard/Stone algorithm, the corresponding number spectrums in slave spectrum set were selected, and then DS algorithm was applied to transfer set to calculate the transformation function between the two sets of data. Finally, the remaining slave spectrums were transformed so that they could apply to the model. This study does some experiment to discuss the impact of the number of transfer set and the location of calibration on the calibration results. Respectively, the experiment results were analyzed from two aspects, one is the correct discrimination rate in qualitative analysis, and the other is the distribution distance between master spectrums and slave spectrums before and after calibration. The experiment results indicate that this approach is effective to solve the spectra drift produced by sampling over time, can bring higher recognition rate on different sampling time test sets, also improves the robustness and application scope of the identification model, and the experiment results also indicate that the best result can be obtained with calibration locating after feature extraction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1533 (2014)
Research on Human Movement with Noninvasive Tissue Oximeter Using Near Infrared Spectroscopy
LIN Hong, XI Yu-bao, and YU Hui
The present paper discusses how to monitor and analyze the relative change in muscle oxygen content in quadriceps tissue, and measures and records the change in blood lactate acid concentration, blood volume and heart rate when eight players who are good at middle-distance races perform grade incremental intensity exerThe present paper discusses how to monitor and analyze the relative change in muscle oxygen content in quadriceps tissue, and measures and records the change in blood lactate acid concentration, blood volume and heart rate when eight players who are good at middle-distance races perform grade incremental intensity exercise on cycle ergometer by using noninvasive tissue oximeter with near infrared spectroscopy produced by China independently. The results show that muscle oxygen content has a close relationship（p<0.01）with exercise load, blood lactic acid, blood volume and heart rate。 When determined muscle oxygen content and blood lactate acid concentration was determined for many times to the same person, the test proved regular falling and rising. There was no significant changes when analyzed each set of the data was analyzed through horizontal comparison. It verifies we can judge the subjects’s endurable exercise intensity and the upward inflection point of blood lactic acid corresponding to the decreasing inflection point of blood lactate acid concentration & muscle oxygen content according to the muscle oxygen content change of skeletal muscle while exercising. This paper shows NIRS research status and present situation in sports field through investigation, and analyzes the main trouble and research tendency in the future. By understanding NIRS technology gradually, the authors can realize that the muscle oxygen content which measured by noninvasive tissue oximeter using near infrared spectroscopy produced by China independently is a sensitive, nondestructive, up-to-date and reliable index, it has irreplaceable advantages when compared with traditional invasive, excised and fussy test methods..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1538 (2014)
The New Method Monitoring Crop Water Content Based on NIR-Red Spectrum Feature Space
CHENG Xiao-juan, XU Xin-gang, CHEN Tian-en, YANG Gui-jun, and LI Zhen-hai
Moisture content is an important index of crop water stress condition, timely and effective monitoring of crop water content is of great significance for evaluating crop water deficit balance and guiding agriculture irrigation. The present paper was trying to build a new crop water index for winter wheat vegetation watMoisture content is an important index of crop water stress condition, timely and effective monitoring of crop water content is of great significance for evaluating crop water deficit balance and guiding agriculture irrigation. The present paper was trying to build a new crop water index for winter wheat vegetation water content based on NIR-Red spectral space. Firstly, canopy spectrums of winter wheat with narrow-band were resampled according to relative spectral response function of HJ-CCD and ZY-3. Then, a new index (PWI) was set up to estimate vegetation water content of winter wheat by improveing PDI (perpendicular drought index) and PVI (perpendicular vegetation index) based on NIR-Red spectral feature space. The results showed that the relationship between PWI and VWC(vegetation water content) was stable based on simulation of wide-band multispectral data HJ-CCD and ZY-3 with R2 being 0.684 and 0.683, respectively. And then VWC was estimated by using PWI with the R2 and RMSE being 0.764 and 0.764, 3.837% and 3.840%, respectively. The results indicated that PWI has certain feasibility to estimate crop water content. At the same time, it provides a new method for monitoring crop water content using remote sensing data HJ-CCD and ZY-3..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1542 (2014)
Identification of Dendrobium Varieties by Fourier Transform Infrared Spectroscopy Combined with Spectral Retrieval
LIU Fei, WANG Yuan-zhong, DENG Xing-yan, JIN Hang, and YANG Chun-yan
The infrared spectral of stems of 165 trees of 23 dendrobium varieties were obtained by means of Fourier transform infrared spectroscopy technique. The spectra show that the spectra of all the samples were similar, and the main components of stem of Dendrobium is cellulose. By the spectral professional software Omnic8.The infrared spectral of stems of 165 trees of 23 dendrobium varieties were obtained by means of Fourier transform infrared spectroscopy technique. The spectra show that the spectra of all the samples were similar, and the main components of stem of Dendrobium is cellulose. By the spectral professional software Omnic8.0, three spectral databases were constructed. Lib01 includes of the average spectral of the first four trees of every variety, while Lib02 and Lib03 are constructed from the first-derivative spectra and the second-derivative spectra of average spectra, separately. The correlation search, the square difference retrieval and the square differential difference retrieval of the spectra are performed with the spectral database Lib01 in the specified range of 1 800～500 cm-1, and the yield correct rate of 92.7%, 74.5% and 92.7%, respectively. The square differential difference retrieval of the first-derivative spectra and the second-derivative spectra is carried out with Lib02 and Lib03 in the same specified range 1 800～500 cm-1, and shows correct rate of 93.9% for the former and 90.3% for the later. The results show that the first-derivative spectral retrieval of square differential difference algorithm is more suitabe for discerning dendrobium varieties, and FTIR combining with the spectral retrieval method can identify different varieties of Dendrobium, and the correlation retrieval, the square differential retrieval, the first-derivative spectra and second-derivative spectra retrieval in the specified spectral range are effective and simple way of distinguishing different varieties of dendrobium..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1548 (2014)
Visible-NIR Spectral Feature of Citrus Greening Disease
LI Xiu-hua, LI Min-zan, Won Suk Lee, Reza Ehsani, and Ashish Ratn Mishra
Citrus greening (Huanglongbing, or HLB) is a devastating disease caused by Candidatus liberibacter which uses psyllids as vectors. It has no cure till now, and poses a huge threat to citrus industry around the world. In order to diagnose, assess and further control this disease, it is of great importance to first find Citrus greening (Huanglongbing, or HLB) is a devastating disease caused by Candidatus liberibacter which uses psyllids as vectors. It has no cure till now, and poses a huge threat to citrus industry around the world. In order to diagnose, assess and further control this disease, it is of great importance to first find a quick and effective way to detect it. Spectroscopy method, which was widely considered as a fast and nondestructive way, was adopted here to conduct a preliminary exploration of disease characteristics. In order to explore the spectral differences between the healthy and HLB infected leaves and canopies, this study measured the visible-NIR spectral reflectance of their leaves and canopies under lab and field conditions, respectively. The original spectral data were firstly preprocessed with smoothing(or moving average) and cluster average procedures, and then the first derivatives were also calculated to determine the red edge position(REP). In order to solve the multi-peak phenomenon problem, two interpolation methods(three-point Lagrangian interpolation and four-point linear extrapolation) were adopted to calculate the REP for each sample. The results showed that there were obvious differences at the visible & NIR spectral reflectance between the healthy and HLB infected classes. Comparing with the healthy reflectance, the HLB reflectance was higher at the visible bands because of the yellowish symptoms on the infected leaves, and lower at NIR bands because the disease blocked water transportation to leaves. But the feature at NIR bands was easily affected by environmental factors such as light, background, etc. The REP was also a potential indicator to distinguish those two classes. The average REP was slowly moving toward red bands while the infection level was getting higher. The gap of the average REPs between the healthy and HLB classes reached to a maximum of 20 nm. Even in the dataset with relatively lower variation, the classification accuracy of threshold segmentation method by the REP could reach to more than 90%. The four-point linear extrapolation method had slightly better result than the three-point Lagrangian interpolation method. This study provided useful theoretical foundation to detect HLB by spectral reflectance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1553 (2014)
Raman Spectroscopic Studies on CO2—CH4—N2 Mixed-Gas Hydrate System
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Accurate determination of coal mine gas separation product characteristics is the key for gas separation application based on hydrate technology. Gas hydrate was synthesized from two types of gas compositions (CO2—CH4—N2). The separation products were measured by in situ Raman spectroscopy. The crystal structure of mixAccurate determination of coal mine gas separation product characteristics is the key for gas separation application based on hydrate technology. Gas hydrate was synthesized from two types of gas compositions (CO2—CH4—N2). The separation products were measured by in situ Raman spectroscopy. The crystal structure of mixed-gas hydrate was determined, and the cavity occupancy and hydration index were calculated, based on the object molecular various vibrational mode, “loose cage-tight cage” model and the Raman bands area ratio, combined with the model of van der Waals-Platteeuw. The results show that the mixed-gas hydrates are both structureⅠ for the two gas samples; Large cages of mixed-gas hydrate are nearly occupied by guest molecules, and the large cavity occupancies are 98.57% and 98.52%, respectively; but small cages are not easy to be occupied, and the small cavity occupancies are 29.93% and 33.87%, respectively; hydration index of the two gas samples hydrate is 7.14 and 6.98, respectively, which is greater than the theoretical value of structure Ⅰ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1560 (2014)
Laser Raman Spectrum Analysis of Carbendazim Pesticide
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Raman signal of solid and liquid carbendazim pesticide was collected by laser Raman spectrometer. The acquired Raman spectrum signal of solid carbendazim was preprocessed by wavelet analysis method, and the optimal combination of wavelet denoising parameter was selected through mixed orthogonal test. The results showedRaman signal of solid and liquid carbendazim pesticide was collected by laser Raman spectrometer. The acquired Raman spectrum signal of solid carbendazim was preprocessed by wavelet analysis method, and the optimal combination of wavelet denoising parameter was selected through mixed orthogonal test. The results showed that the best effect was got with signal to noise ratio (SNR) being 62.483 when db2 wavelet function was used, decomposition level was 2, the threshold option scheme was ‘rigrsure’ and reset mode was ‘sln’. According to the vibration mode of different functional groups, the de-noised Raman bands could be divided into 3 areas: 1 400～2 000, 700～1 400 and 200～700 cm-1. And the de-noised Raman bands were assigned with and analyzed. The characteristic vibrational modes were gained in different ranges of wavenumbers. Strong Raman signals were observed in the Raman spectrum at 619, 725, 964, 1 022, 1 265, 1 274 and 1 478 cm-1, respectively. These characteristic vibrational modes are characteristic Raman peaks of solid carbendazim pesticide. Find characteristic Raman peaks at 629, 727, 1 001, 1 219, 1 258 and 1 365 cm-1 in Raman spectrum signal of liquid carbendazim. These characteristic peaks were basically tallies with the solid carbendazim. The results can provide basis for the rapid screening of pesticide residue in food and agricultural products based on Raman spectrum..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1566 (2014)
Revealing the Chemical Changes of Tea Cell Wall Induced by Anthracnose with Confocal Raman Microscopy
LI Xiao-li, LUO Liu-bin, HU Xiao-qian, LOU Bing-gan, and HE Yong
Healthy tea and tea infected by anthracnose were first studied by confocal Raman microscopy to illustrate chemical changes of cell wall in the present paper. Firstly, Raman spectra of both healthy and infected sample tissues were collected with spatial resolution at micron-level, and ultrastructure of healthy and infecHealthy tea and tea infected by anthracnose were first studied by confocal Raman microscopy to illustrate chemical changes of cell wall in the present paper. Firstly, Raman spectra of both healthy and infected sample tissues were collected with spatial resolution at micron-level, and ultrastructure of healthy and infected tea cells was got from scanning electron microscope. These results showed that there were significant changes in Raman shift and Raman intensity between healthy and infected cell walls, indicating that great differences occurred in chemical compositions of cell walls between healthy and infected samples. In details, intensities at many Raman bands which were closely associated with cellulose, pectin, esters were reduced after infection, revealing that the content of chemical compounds such as cellulose, pectin, esters was decreased after infection. Subsequently, chemical imaging of both healthy and infected tea cell walls were realized based on Raman fingerprint spectra of cellulose and microscopic spatial structure. It was found that not only the content of cellulose was reduced greatly after infection, but also the ordered structure of cellulose was destroyed by anthracnose infection. Thus, confocal Raman microscopy was shown to be a powerful tool to detect the chemical changes in cell wall of tea caused by anthracnose without any chemical treatment or staining. This research firstly applied confocal Raman microscopy in phytopathology for the study of interactive relationship between host and pathogen, and it will also open a new way for intensive study of host-pathogen at cellular level..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1571 (2014)
A Simple Solution Hybridization Rapidly Detects DNA by Fluorescent Probe
MAO Qiang, GENG Tian-long, and WANG Sheng-hua
Traditional Southern blot, as the golden standard to detect DNA, is widely used in molecular biology. However, its operation process has some significant disadvantages, such as radioactive contamination, complex procedures, time-consuming. Some new methods developed in recent years need expensive equipments and also haTraditional Southern blot, as the golden standard to detect DNA, is widely used in molecular biology. However, its operation process has some significant disadvantages, such as radioactive contamination, complex procedures, time-consuming. Some new methods developed in recent years need expensive equipments and also have the defects of complex procedures and time-consuming. The paper described a method to detect DNA quickly by liquid hybridization. The probe used is a fragment of DNA sequence labeled by FITC-12-dUTP. The whole process includes four steps: probe preparation, hybridization, electrophoresis and signal detection. The comparative experiments using the single strand DNA probe and the double strand DNA probe indicated that the sensitivity of single strand DNA probes, which could detect 0.38μg (1.82×10-13 mol) plasmid, is 2.1 times than that of the double strand DNA probes which could detect 0.8 μg(3.64×10-13 mol) plasmid. The total procedure is simple and can be completed in 3 h..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1577 (2014)
Analysis of Spatial Distribution Characteristics of Dissolved Organic Matter in Typical Greenhouse Soil of Northern China Using Three Dimensional Fluorescence Spectra Technique and Parallel Factor Analysis Model
PAN Hong-wei, LEI Hong-jun, HAN Yu-ping, XI Bei-dou, HE Xiao-song, XU Qi-gong, LI Dan, and SONG Cai-hong
The aim of the present work is to study the soil DOM characteristics in the vegetable greenhouse with a long-term of cultivation. Results showed that the soil DOM mainly consisted of three components, fulvic acid-like (C1), humic acid-like (C2) and protein-like (C3), with C1 as the majority one. The distribution of DOMThe aim of the present work is to study the soil DOM characteristics in the vegetable greenhouse with a long-term of cultivation. Results showed that the soil DOM mainly consisted of three components, fulvic acid-like (C1), humic acid-like (C2) and protein-like (C3), with C1 as the majority one. The distribution of DOM in space was also studied. In vertical direction, C1 and C2 decreased significantly with the increase in soil depth, while C3 component decreased after increased. The humification coefficient decreased fast from 0~20 to 30~40 cm, and then increased from 30~40 to 40~50 cm. In the horizontal direction, the level of C2 component varied greatly in space, while that of C1 component changed little, and that of C3 component fell in between the above two. The change in the humification degree of each soil layer significantly varied spatially. Humification process of soil organic matter mainly occurred in the surface soil layer. In addition, the humification degree in space also changed significantly. The new ideas of this study are: (1) Analyze the composition and spatial heterogeneity of soil DOM in the vegetable greenhouse; (2) Use three dimensional fluorescence spectra technology and parallel factor analysis model successfully to quantify the components of soil DOM, which provides a new method for the soil DOM analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1582 (2014)
Determination of Palmatine Hydrochloride Based on the Interaction with Morin by Resonance Light Scattering Technique
LI Jia-yu, LI Hua-chun, WU Fei, and TAN Ke-jun
A novel resonance light scattering method for the determination of PaH was developed based on the interaction of Palmatine hydrochloride (PaH) with Morin in pH 4.6 HAc-NaAc buffer medium, and this interaction can result in largely enhanced resonance light scattering (RLS) signal characterized by a peak at 308.0 nm. It A novel resonance light scattering method for the determination of PaH was developed based on the interaction of Palmatine hydrochloride (PaH) with Morin in pH 4.6 HAc-NaAc buffer medium, and this interaction can result in largely enhanced resonance light scattering (RLS) signal characterized by a peak at 308.0 nm. It was found that the enhanced RLS signals intensity (IRLS) at 308.0 nm is proportional to the concentration of PaH. The limit of detection is 8.0 nmol·L-1 and the linear range is from 0.08 to 1.0 mol·L-1. In this study, the mechanism of this reaction was investigated by scanning electron microscope (SEM), dynamic light scattering (DLS) and UV absorption spectrum. The SEM images and DLS graph show that ion-association complex aggregated after the addition of PaH. The experimental condition optimization results indicate that when the buffer medium is pH 4.6 HAc-NaAc without adding NaCl, the system has a good response for PaH. The authors investigated the stability of this system. The results indicate that this reaction system has a rapid response and the IRLS can reach the maximum within 5 min and remain stable at least for 120 min. The tolerance of coexisting foreign substances in the system was also studied. The research results show that the common metal ions, inorganic anions, a part of carbohydrate and amino acids have negligible effects on the analysis of PaH. This proposed method has some advantages including simplicity, rapidity and sensitivity. It also has been applied to the detection of PaH in tablet and capsule samples with RSD≤3.3%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1589 (2014)
Experimental Study on Closed Plasma Discharging under Low Pressure and Spectroscopic Diagnosis
LIN Min, XU Hao-jun, SU Chen, LIANG Hua, and WEI Xiao-long
Closed plasma can overcome difficulties of maintaining plasma and excessive energy consumption in open environment. For plasma stealth technology, a closed plasma generator was designed. Using microsecond pulse generator and argon as working gas, discharge experiments were carried out under low pressure environment. ThClosed plasma can overcome difficulties of maintaining plasma and excessive energy consumption in open environment. For plasma stealth technology, a closed plasma generator was designed. Using microsecond pulse generator and argon as working gas, discharge experiments were carried out under low pressure environment. The emission spectrum of Ar at different position in discharge chamber was measured. By using collisional-radiative modal(CRM), the distribution of plasma parameters was studied. At a given electron temperature and density with specified discharge parameters, corresponding population distribution could be obtained by CRM. By comparing the line ratio of argon 2p levels acquired from CRM with the line ratio from spectrum measured, the plasma parameters were confirmed after obtaining the minimum difference value. Using the line ratio of argon 2p9 to 2p1 from CRM while the range of electron density was 1~5 eV, the calculating error was analyzed. The results reveal that, the electron density of the closed plasma reaches a magnitude of 1011 cm-3 and shows a gradient distribution with small variational amplitude, and the distribution is beneficial to the application of plasma stealth..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1594 (2014)
Assessment of Chlorophyll Content Using a New Vegetation Index Based on Multi-Angular Hyperspectral Image Data
LIAO Qin-hong, ZHANG Dong-yan, WANG Ji-hua, YANG Gui-jun, YANG Hao, Coburn Craig, Wong Zhijie, and WANG Da-cheng
The fast estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. This study gets the hyperspectral imagery data by using a self-developed multi-angular acquisition system during the different maize growth period, the refleThe fast estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. This study gets the hyperspectral imagery data by using a self-developed multi-angular acquisition system during the different maize growth period, the reflectance of maize canopy was extracted accurately from the hyperspectral images under different view angles in the principal plane. The hot-dark-spot index (HDS) of red waveband was calculated through the analysis of simulated values by ACRM model and measured values, then this index was used to modify the vegetation index (TCARI), thus a new vegetation index (HD-TCARI) based on the multi-angular observation was proposed. Finally, the multi-angular hyperspectral imagery data was used to validate the vegetation indexes. The result showed that HD-TCARI could effectively reduce the LAI effects on the assessment of chlorophyll content. When the chlorophyll content was greater than 30 μg·cm-2, the correlation (R2) between HD-TCARI and LAI was only 26.88%～28.72%. In addition, the HD-TCARI could resist the saturation of vegetation index during the assessment of high chlorophyll content. When the LAI varied from 1 to 6, the linear relation between HD-TCARI and chlorophyll content could be improved by 9% compared with TCARI. The ground validation of HD-TCARI by multi-angular hyperspectral image showed that the linear relation between HD-TCARI and chlorophyll content (R2=66.74%) was better than the TCARI (R2=39.92%), which indicated that HD-TCARI has good potentials for estimating the chlorophyll content..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1599 (2014)
A Novel Vegetation Index (MPRI) of Corn Canopy by Vehicle-Borne Dynamic Prediction
LI Shu-qiang, LI Min-zan, and SUN Hong
Ground-based remote sensing system is a significant way to understand the growth of corn and provide accurate and scientific data for precision agriculture. The vehicle-borne system is one of the most important tools for corn canopy monitoring. However, the vehicle-borne growth monitoring system cannot maintain steady Ground-based remote sensing system is a significant way to understand the growth of corn and provide accurate and scientific data for precision agriculture. The vehicle-borne system is one of the most important tools for corn canopy monitoring. However, the vehicle-borne growth monitoring system cannot maintain steady operations due to the row spacing of corn. The reflectance of corn canopy, which was used to construct the model for the chlorophyll content, was disturbed by the reflectance of soil background. The background interference with the reflectance could not be removed effectively, which would result in a deviation in the growth monitoring. In order to overcome this problem, a novel vegetation index named MPRI was developed in the present paper. The tests were carried out by the vehicle-borne system on the cornfield. The sensors which configured the vehicle-borne system had 4 bands, being respectively 550, 650, 766 and 850 nm. It would obtain the spectral data while the vehicle moved along the row direction. The sampling rate was about 1 point per second. The GPS receiver obtained the location information at the same rate. MPRI was made up by the reflectance ratio of 660 and 550 nm. It was very effective to analyze the information about the reflectance of the canopy. The results of experiments showed that the MPRI of soil was the positive value and the MPRI of canopy was the negative value. So it is easier to distinguish the spectral information about soil and corn canopy by MPRI. The results indicated that: it had satisfactory forecasting accuracy for the chlorophyll content by using the MPRI on the moving monitoring. The R2 of the prediction model was about 0.72. The R2 of the model of NDVI, which was used to represent the chlorophyll content, was only 0.24. It indicates that MPRI had good measurement results for the dynamic measurement process. It provided the novel measurement way to get the canopy reflectance spectra and the better vegetation index to construct the prediction model of the contents of chlorophyll..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1605 (2014)
Studies on the Effects of Cucurbit(n=7)uril on the Physicohemical Properties and Anticancer Activity of 10-Hydroxycamptothecin
Lv Yan, YAN Li-fen, and DONG Nan
The changes in the physicochemical properties and the anticancer activity of 10-Hydroxycamptothecin(HCPT) in the presence of Cucurbit(n=7)uril(Q) were studied by using UV absorption spectroscopy, fluorescence spectroscopy and phase solubility method. The results revealed that in the acid solution (pH 2), the absorptionThe changes in the physicochemical properties and the anticancer activity of 10-Hydroxycamptothecin(HCPT) in the presence of Cucurbit(n=7)uril(Q<参考文献原文>) were studied by using UV absorption spectroscopy, fluorescence spectroscopy and phase solubility method. The results revealed that in the acid solution (pH 2), the absorption band of the guest HCPT exhibited a progressively lower absorbance at λ265 nm, while a progressively higher absorbance at λ425 nm as the ratio of NQ<参考文献原文>/NHCPT was increased. A sharp isosbestic point at λ387 nm was consistent with a simple interaction between Q<参考文献原文> and HCPT. The emission spectra of the guest HCPT also exhibited a progressive decrease in fluorescence intensity at λ558 nm with a violet shift when the ratio of NQ<参考文献原文>/NHCPT was increased. The measured data from both absorption spectrophotometric and fluorescence spectroscopy analysis fitted to a 2∶1 host:guest complexation, yielded a calculated stable constants (β) of 1.549×1013 L2·mol-2and 0.907×1013 L2·mol-2 respectively through Reactlab EQULLIBRIA software○R. The effect of Q<参考文献原文> on the solubility of HCPT was investigated by using phase solubility method. Upon the addition of Q<参考文献原文> concentration, the solubility of HCPT was enhanced step by step at the value of pH 2 and an about 250 times advance was attained when the concentration of Q<参考文献原文> was 1×10-3 mol·L-1, while the Q<参考文献原文>-HCPT inclusion complex made by total evaporation method can increase about 1 170 times compared to the pure HCPT. At the end, the mixtures of Q<参考文献原文> and HCPT were tested in terms of cytotoxicity on the human lung cancer cell line A549 and human leukemia cell line K562 to compare their reactivity with the free HCPT and the comparative cytotoxic activity was got for A549 and K562..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1610 (2014)
Soil Moisture Estimation Model based on Multiple Vegetation Index
WU Hai-long, YU Xin-xiao, ZHANG Zhen-ming, and ZHANG Yan
Estimating soil moisture conveniently and exactly is a hot issues in water resource monitoring among agriculture and forestry. Estimating soil moisture based on vegetation index has been recognized and applied widely. 8 vegetation indexes were figured out based on the hyper-spectral data measured by portable spectrometEstimating soil moisture conveniently and exactly is a hot issues in water resource monitoring among agriculture and forestry. Estimating soil moisture based on vegetation index has been recognized and applied widely. 8 vegetation indexes were figured out based on the hyper-spectral data measured by portable spectrometer. The higher correlation indexes among 8 vegetation indexes and surface vegetation temperature were selected by Gray Relative Analysis method (GRA). Then, these selected indexes were analyzed using Multiple Linear Regression to establish soil moisture estimation model based on multiple vegetation indexes, and the model accuracy was evaluated. The accuracy evaluation indicated that the fitting was satisfied and the significance was 0.000 (P<0.001). High correlation was turned out between estimated and measured soil moisture with R2 reached 0.636 1 and RMSE 2.149 9. This method introduced multiple vegetation indexes into soil water content estimating over micro scale by non-contact measuring method using portable spectrometer. The exact estimation could be an appropriate replacement for remote sensing inversion and direct measurement. The model could estimate soil moisture quickly and accurately, and provide theory and technology reference for water resource management in agriculture and forestry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1615 (2014)
Determination of Trace Amounts of Nitrite and Its Chemical Reaction Kinetics
LUO Zhi-yong, and ZHENG Huai-li
A catalytic kinetic spectrophotometric method for the determination of nitrite, NO2--S2O2-8-MR, was developed. It is based on the fading reaction of methyl red (MR) oxidized by potassium persulfate which can be catalyzed by NO-2 in the medium of dilute HCl. The optimum experimental conditions were gained by combining sA catalytic kinetic spectrophotometric method for the determination of nitrite, NO2--S2O2-8-MR, was developed. It is based on the fading reaction of methyl red (MR) oxidized by potassium persulfate which can be catalyzed by NO-2 in the medium of dilute HCl. The optimum experimental conditions were gained by combining single factor experiments with orthogonal experiments. Calibration curve, detection limit, precision, and anti-interference under the optimum experimental conditions were researched. Its kinetics principles and parameters were discussed. Its quantitative principle was investigated. The results show that the optimum experimental conditions of this method should be as follows: 1.0 mL 0.3 mol·L-1 HCl, 1.0 mL 0.01 mol·L-1 K2S2O8, 0.6 mL 0.2 g·L-1 MR, reaction temperature 80 ℃ and reaction time 9 min. The principles for the quantitative determination of trace nitrite is that variation of MR concentration at the maximum absorption wavelength of 518 nm, ln(A0/A), shows a good linear relationship with the concentration of NO-2 under the optimum experimental conditions. Its determination range is 0.01～0.80 mg·L-1 and its detection limit is 0.007 mg·L-1. The kinetic characteristics are that the reaction order in NO-2 is 1 and the fading reaction is a pseudo first order reaction. Its apparent activation energy is 85.04 kJ·mol-1. Its apparent rate constant is 0.021 4 min-1, and the half-life is 32.39 min at 80 ℃. The kinetic principle is that the variation of MR concentration is directly proportional to the concentration of NO-2, ln(A0/A)=kｃNO-2. This new method for the determination of trace nitrite has never previously been reported in the published literature so far. It is highly sensitive and selective. Most of the common ions don’t interfere with the determination of nitrite. This method has the advantages of convenient operation and the regents used are cheap and nontoxic. It was applied to the determination of trace nitrite in food and water samples with satisfactory results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1619 (2014)
Adaptive EEMD Residue Related Baseline Correction Algorithm
ZHAO Xiao-yu, FANG Yi-ming, GUAN Yong, WANG Zhi-gang, TONG Liang, and TAN Feng
Baseline correction is an important part of spectral analysis; the existing algorithms usually need to set the key parameters and does not have adaptability. The spectral baseline is fitted by the residue according to the feature of ensemble empirical mode decomposition (EEMD for short). The correlation between residuaBaseline correction is an important part of spectral analysis; the existing algorithms usually need to set the key parameters and does not have adaptability. The spectral baseline is fitted by the residue according to the feature of ensemble empirical mode decomposition (EEMD for short). The correlation between residual and original signal, the self-correlation and the crosscorrelation of residual form the residual related rule. The residual related rule is proposed to judge whether the residual is a component of baseline, based on which adaptive EEMD residual related base line algorithm is proposed. With experiment on the simulated spectrum data of superimposing curve background and the linear background, the results showed that in the case of known baseline mathematical assumption: EEMD residual related method is not so good for polynomial fitting, it is almost no difference from linear fitting, but is better than the wavelet decomposition. In the absence of spectral background knowledge, the real Raman spectrum data are tested. The model is established between Raman spectra treated by the procedure above and chlorophyll, and the model corrected by EEMD residual related baseline method has the biggest correlation coefficient and prediction coefficient, but the smallest root mean square error of cross validation and relative prediction deviation. The effect of EEMD residual related baseline method effects on the peak position, peak intensity and peak width is the smallest in all kinds of baseline correction methods. EEMD residual method has the best baseline correction effect. Experiments show that this algorithm can be used for Raman spectra baseline correction, without prior knowledge of the sample composition analysis, and there is no need to select appropriate fitting function, fitting data points, fitting order as well as basis function and decomposition levels, also there is no need of mathematical hypothesis of baseline signal distribution, so the adaptability is very strong..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1624 (2014)
Construction of Age Group Vegetation Index and Preliminary Application
XU Zhang-hua, LI Cong-hui5, LIU Jian, YU Kun-yong, GONG Cong-hong, TANG Meng-ya, and LAI Ri-wen
In the present paper, one remote sensing index-age group vegetation index (AGVI) was put forward, and its feasibility was verified. Taking 518 groups of pine forest age group data collected in 13 counties (cities) of Sanming, Jiangle, Shaxian, Nanping, Huaan, Yunxiao, Nanping, Anxi, Putian, Changting, Jianyang, Ningde In the present paper, one remote sensing index-age group vegetation index (AGVI) was put forward, and its feasibility was verified. Taking 518 groups of pine forest age group data collected in 13 counties (cities) of Sanming, Jiangle, Shaxian, Nanping, Huaan, Yunxiao, Nanping, Anxi, Putian, Changting, Jianyang, Ningde and Fuqing, Fujian Province and HJ-1 CCD multi-spectral image at the same time-phase as the basis, the spectrum differences of blue, green, red, near infrared and NDVI of each age group were analyzed, showing the characteristics of young forest>middle-aged forest>over-mature forest>mature forest>near mature forest at near infrared band and mature forest>near mature forest>over-mature forest>young forest>middle-aged forest at NDVI, thus the age group vegetation index(AGVI) was constructed; the index could increase the absolute and relative spectrum differences among age groups. For the pine forest AGVI, cluster analysis was conducted with K-mean method, showing that the division accuracy of pine forest age group was 80.45%, and the accurate rate was 90.41%. Therefore, the effectiveness of age group vegetation index constructed was confirmed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1629 (2014)
Research on Characteristic Spectrum Extracting and Matching for High-Fidelity Reproduction
YANG Sheng-wei, LIU Zhen, WU Ming-guang, and ZHANG Zhen-jie
Reconstructing the spectrum rapidly and accurately is the key to the research on high-fidelity reproduction. A characteristic spectrum extracting and matching method for high-fidelity printing is proposed aiming at the problem of complex conversion between spectrum and ink combination caused by multi-color. The method Reconstructing the spectrum rapidly and accurately is the key to the research on high-fidelity reproduction. A characteristic spectrum extracting and matching method for high-fidelity printing is proposed aiming at the problem of complex conversion between spectrum and ink combination caused by multi-color. The method filters and extracts feature bands of primary ink through derivative spectrum, and a characteristic spectrum multi-threshold coding method is proposed. Considering the problem of subarea judgment in hi-fi printing, an average derivative spectrum is taken as characteristic spectrum of each subarea and a spectrum matching method between target spectrum and average derivative spectrum of sub-spaces is proposed. The results show that the feature bands extracted can represent spectral characteristic of primary color significantly and the precision of color conversion model based on feature bands is higher than the model based on full bands. The spectrum matching method can achieve a high accuracy in sub-space judgments and greatly improve the efficiency of color convention. The spectrum extracting and matching method has the high practicability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1635 (2014)
Study on the Polarized Reflectance Hyperspectral Characteristics and Models of Typical Saline Soil in the West of Jilin Province, China
HAN Yang, QIN Wei-chao, and WANG Ye-qiao
In recent years, the area of saline soil in the west of Jilin Province expands increasingly, and soil quality is becoming more and more worsening, which not only caused great damage to the land resources, but also posed a huge threat to agricultural production and ecological environment. We combined with polarized and In recent years, the area of saline soil in the west of Jilin Province expands increasingly, and soil quality is becoming more and more worsening, which not only caused great damage to the land resources, but also posed a huge threat to agricultural production and ecological environment. We combined with polarized and hyperspectral information to establish the general model and scientifically validated it. The results show that there is a strong relationship between the saline soil hyperspectral polarized information and its physicochemical property parameters, and with regularity. This paper has important theoretical significance for the mechanism of saline soil surface reflection, recognition and classification of saline soil and background, the utilization of soil polarization sensor and the development of quantitative remote sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1640 (2014)
Estimating Polysaccharide Content with Hyperspectral in Dendrobium Officinale
ZHANG Yin-tao, GE Hong-li, SUN Zhen, and ZOU Hong-yu
The objectives in the present paper were to study the relationship between the polysaccharide content and the spectrum, aimed at finding a non destructive testing method for the measurement of polysaccharide content. Materials in this study were from tissue culture seedlings under different treatments and domesticated The objectives in the present paper were to study the relationship between the polysaccharide content and the spectrum, aimed at finding a non destructive testing method for the measurement of polysaccharide content. Materials in this study were from tissue culture seedlings under different treatments and domesticated plants in different growth stages. In the study, 36 samples were used to build estimation models and another 11 as test samples to examine the models. The relationship between the spectrum and polysaccharide content was investigated by partial least squares regression (PLSR) and factor analysis. The results show that (1) there was stronger correlation between derivative reflectance and polysaccharide content, and the sensitive wavebands mainly concentrated in the visible region. (2) The PLSR model has a high precision, while its prediction accuracy is lower. The models of factor analysis have higher prediction accuracy, the RPD of the model based on spectral reflectance is 2.269 and that of derivative reflectance is 2.305..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1645 (2014)
Researches of Soil Normalized Difference Water Index （NDWI） of Yongding River Based on Multispectral Remote Sensing Technology Combined with Genetic Algorithm
MAO Hai-ying, FENG Zhong-ke, GONG Yin-xi, and YU Jing-xin
Basin soil type, moisture content and vegetation cover index are important factors affecting the basin water of Yongding River, using traditional sampling method to investigate soil moisture and the watershed soil type not only consuming a lot of manpower and material resources but also causing experimental error becauBasin soil type, moisture content and vegetation cover index are important factors affecting the basin water of Yongding River, using traditional sampling method to investigate soil moisture and the watershed soil type not only consuming a lot of manpower and material resources but also causing experimental error because of the instrument and other objective factors. This article selecting the Yongding River Basin-Beijing section as the study area, using total station instruments to survey field sampling and determination 34 plots, combined with 6 TM image data from 1978 to 2009 to extract soil information and the relationship between region’s soil type, soil moisture and remote sensing factors. Using genetic algorithms normalization to select key factors which influenced NDWI, which is based on the green band and near-infrared bands normalized ratio index, usually used to extract water information in the image. In order to accurate screening and factors related to soil moisture, using genetic algorithms preferred characteristics, accelerate the convergence by controlling the number of iterations to filter key factor. Using multiple regression method to establish NDWI inversion model, which analysis the accuracy of model is 0.987, also use the species outside edges tree to meet accuracy test, which arrived that soil available nitrogen, phosphorus and potassium content and longitude correlation is not obvious, but a positive correlation with latitude and soil, inner precision researched 87.6% when the number of iterations to achieve optimal model calculation Maxgen. Models between NDWI and vegetation cover, topography, climate ect, through remote sensing and field survey methods could calculate the NDWI values compared with the traditional values, arrived the average relative error E is -0.021%, suits accord P reached 87.54%. The establishment of this model will be provide better practical and theoretical basis to the research and analysis of the watershed soil moisture and organic of Yongding River..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1649 (2014)
Hyperspectral Extraction of Soil Available Nitrogen in Nan Mountain Coal Waste Scenic Spot of Jinhuagong Mine Based on Enter-PLSR
LIN Li-xin, WANG Yun-jia, and XIONG Ji-bing
Soil available nitrogen content is an important index reflecting soil fertility. It provides dynamic information for land reclamation and ecological restoration if soil available nitrogen can be monitored and evaluated using hyperspectral technology. Facing the study blank of soil available nitrogen in National Mine PaSoil available nitrogen content is an important index reflecting soil fertility. It provides dynamic information for land reclamation and ecological restoration if soil available nitrogen can be monitored and evaluated using hyperspectral technology. Facing the study blank of soil available nitrogen in National Mine Park and the deficiency of poor computational efficiency of partial least squares regression (PLSR) method, the present paper presents the relationship between soil spectrum and soil available nitrogen based on spectrum curves (ranging from 350 to 2 500 nm) of 30 salinized chestnut soil samples, which were collected from southern mountain coal waste scenic spot, located in Jinhuagong mine in Datong city, Shanxi Province, China (one part of Jinhuagong national mine park). Soil reflection spectrum was mathematically manipulated into first derivative and inverse-log spectral curves, then a corresponding estimation model was built and examined by PLSR and Enter-partial least squares regression (Enter-PLSR) based on characteristic absorption. The result indicated that Enter-PLSR corresponding estimation model greatly increased the computation efficiency by reducing the number of independent variables to 12 from 122 in case of a close accuracy of PLS corresponding estimation model. By using hyperspectral technology and Enter-PLSR method, the study blank of soil available nitrogen in National Mine Park was filled. At the same time, the computation efficiency problem of PLSR was resolved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1656 (2014)
Spectral Inversion Models for Prediction of Total Chromium Content in Subtropical Soil
WU Ming-zhu, LI Xiao-mei, and SHA Jin-ming
With the high requirements and long test cycle of traditional testing method of soil heavy metal, this paper tries to establish the quantitative prediction model between soil hyperspectral and soil chromium content(tested by ICP-MS) to realize the prediction of soil chromium element quickly and accurately. The paper stWith the high requirements and long test cycle of traditional testing method of soil heavy metal, this paper tries to establish the quantitative prediction model between soil hyperspectral and soil chromium content(tested by ICP-MS) to realize the prediction of soil chromium element quickly and accurately. The paper studied the hyperspectral response characteristics of red soil, with 135 soil samples in Fuzhou city. After monitoring the hypersectral reflection of soil samples with ASD (analytical spectral device) and total chromium contents with ICP-MS, the paper gained the spectral reflection data between 350 and 2 500 nm and soil total chromium contents. Then the paper treated the hyperspectral reflection data with 6 mathematic changes such as reciprocal logarithmic change, differentials and continuum removal in advance. The next step was to calculate the correlation coefficient of soil chromium and the above spectral information, and select the sensitive spectral bands according to the highest correlation coefficient. Finally, six kinds of models were selected to build the soil total chromium content model, and the final optimal mathematic model between soil chromium and hyperspectral information was significantly determined. Results showed that 520～530, 1 440～1 450, 2 010～2 020, and 2 230～2 240 nm were the main sensitive bands to soil total chromium, y=120.768e-7.037x was the optimal soil total chromium predicting model(in the model, the correlation coefficient R and the RMSE of total chromium were 0.568 and 0.619 μg·g-1, and the inspection correlation coefficient R and the RMSE were 0.484 μg·g-1 and 1.426 μg·g-1 respectively). The model can be used to rapidly monitor soil total chromium with hyperspectral reflection in Fuzhou area..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1660 (2014)
Enhancement Effect of Laser-Processed Aqueous Solution on ICP Source Radiation
SU Hong-xin, XU Li-jing, CHEN Jin-zhong, LI Xu, and WEN Nuan
To enhance the intensity of inductively coupled plasma-atomic emission spectrum and improve the detection level of trace heavy metal elements, the surface tension and viscosity of the aqueous solution processed by near-infrared laser at wavelength of 976 nm were studied in the present paper. The influences of the treatTo enhance the intensity of inductively coupled plasma-atomic emission spectrum and improve the detection level of trace heavy metal elements, the surface tension and viscosity of the aqueous solution processed by near-infrared laser at wavelength of 976 nm were studied in the present paper. The influences of the treated solution on the spectral line intensity and signal-to-background ratio of the ICP source were observed. The results showed that when the laser irradiation time was 60min and the power density was 0.329 6 W·cm-2, the surface tension and viscosity of the solution decreased by 36.73% and 9.73% respectively compared to the untreated solution. Under the optimum conditions, the aqueous solution treated by the laser irradiation was introduced into the ICP source. By measuring the intensity of emission spectrum of the sample elements, the spectral line intensity of Cd, Cr, Cu, Hg, and Pb was enhanced by about 73.52%, 22.97%, 33.86%, 24.44% and 65.59% compared to the untreated solution, while the signal-to-background ratio increased by 76.03%, 21.74%, 32.17%, 22.68% and 65.32%, respectively. Spectral line intensity and signal-to-background ratio of the ICP source were significantly improved so that the foundation was established for reducing the analysis detection limits. Further more, the surface tension and viscosity of the processed aqueous solution remain the same within 30 minutes standing time with the stable physical properties. This simple and easy method of laser-processed aqueous solution helps improve the detection capabilities of ICP spectrometry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1667 (2014)
Determination of Sodium, Magnesium, Calcium, Lithium and Strontium in Natural Mineral Drinking Water by Microwave Plasma Torch Spectrometer with Nebulization Sample Introduction System
ZHOU Wei, XIONG Hai-long, FENG Guo-dong, YU Ai-min, and CHEN Huan-wen
The microwave plasma torch (MPT) was used as the emission light source. Aqueous samples were introduced with a nebulizer and a desolvation system. A method for the determination of Na, Mg, Ca, Li and Sr in natural mineral drinking water by argon microwave plasma torch spectrometer (ArMPT spectrometer) was established. The microwave plasma torch (MPT) was used as the emission light source. Aqueous samples were introduced with a nebulizer and a desolvation system. A method for the determination of Na, Mg, Ca, Li and Sr in natural mineral drinking water by argon microwave plasma torch spectrometer (ArMPT spectrometer) was established. The effects of microwave power, flow rate of carrier gas and support gas were investigated in detail and these parameters were optimized. Under the optimized condition, the experiments for the determination of Na, Mg, Ca, Li and Sr in 11 kinds of bottled mineral drinking water were carried out by ArMPT spectrometer. The limit-of-detection (LOD) of Na, Mg, Ca, Li and Sr was found to be 4.4, 21, 56, 11 and 84 μg·mL-1, respectively. Relative standard deviation (n=6) was in the range of 1.30%～5.45% and standard addition recoveries were in the range of 84.6 %～98.5 %. MPT spectrometer was simpler, more convenient and of lower cost as compared to ICP unit. MPT spectrometer demonstrated its rapid analysis speed, accuracy, sensitivity and simultaneous multi-element analysis ability during the analysis process. The results showed that MPT spectrometer was suitable for metal elements detection for natural mineral drinking water. This approach provides not only one way for resisting the illegal dealings, but also a security for the quality of drinking water. Moreover, the usability of MPT spectrometer in the field of food security; drug safety; clinical diagnostic is promised..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1671 (2014)
Determination of Arsenic Speciation in Scomberomorus Niphonius by Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry
CHEN Fa-rong, ZHENG Li, WANG Zhi-guang, SUN Jie, HAN Li-hui, and WANG Xiao-ru
A method for the detection of arsenocholine(AsC), arsenobetaine(AsB), As(Ⅲ), dimethylarsinic(DMA), monomethylarsonic(MMA) and As(Ⅴ) by capillary electrophoresis-inductively coupled plasma mass spectrometry(CE-ICP-MS) was established. The results showed that the six species of arsenic were separated within 20 min under A method for the detection of arsenocholine(AsC), arsenobetaine(AsB), As(Ⅲ), dimethylarsinic(DMA), monomethylarsonic(MMA) and As(Ⅴ) by capillary electrophoresis-inductively coupled plasma mass spectrometry(CE-ICP-MS) was established. The results showed that the six species of arsenic were separated within 20 min under the optimized conditions. Good linearities of 6 arsenic species were observed in the range from 2 to 50 μg·L-1 with the linear correlation greater than 0.996, the detection limits were 0.10~1.08 μg·L-1 and the RSDs (n=5) of the peak areas were smaller than 7%. The method was successfully adopted to the determination of the species in scomberomorus niphonius. The recoveries were between 93% and 98%, and we found the arsenobetaine(AsB) was the main species in the sample. The method was suitable for the analysis of other biological samples with the advantages of good stability, less sample consumption, short analysis time and convenience..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1675 (2014)
Subcellular Distribution of Trace Elements in Wound Granulation Tissue of Severe Burn Patients by Inductively Coupled Plasma Mass Spectrometry
XU Xiang-rong, XIE Hua-lin, FU Liang, YANG Hua-juan, and HUANG Jian-hua
A method for simultaneous and quantitative determination of Cr, Mn, Fe, Co, Cu, Zn, Se and Cd elements in the subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol of wound granulation tissue of severe burn patients by octopole reaction system (ORS) inductively coupled plasma mass spectrometry A method for simultaneous and quantitative determination of Cr, Mn, Fe, Co, Cu, Zn, Se and Cd elements in the subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol of wound granulation tissue of severe burn patients by octopole reaction system (ORS) inductively coupled plasma mass spectrometry (ICP-MS) was established. Using differential centrifugation, the sample is separated into different subcellular fractions. The subcellular fraction was digested by HNO3+H2O2 with microwave digestion followed by dilution with ultrapure water then the above 8 trace elements in the solution were analyzed directly by ICP-MS. In the presented method, using ORS eliminates the polyatomic interferences caused by the matrixes. Rh as internal standard element was used to compensate matrix effect and signal drift. The detection limits of the 8 elements are in the range of 0.72～33.05 ng·L-1, and the RSD is less than 8.4%. The results showed that the levels of some elements in subcellular fractions of wound granulation tissues were significantly different from those of normal skin tissues. ORS-ICP-MS is a useful tool for simultaneous determination of multi-elements in wound granulation tissue of severe burn patients, and could be widely used in other biological samples analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1679 (2014)
Application of Microwave Digestion/AAS in Detecting Crankshaft Bearing Knock
CHEN Li-dan, and ZHAO Yan-ru
The present study was carried out to detect crankshaft bearing knock using atomic absorption spectrometry (AAS) in an innovative way. Lubricating oil of MAGOTAN 2.0 with mileage of 1000~28000Km and sampling interval of 1000Km changed into atomic vapor in the heat after digesting with microwave. Hollow-cathode lamp madeThe present study was carried out to detect crankshaft bearing knock using atomic absorption spectrometry (AAS) in an innovative way. Lubricating oil of MAGOTAN 2.0 with mileage of 1000~28000Km and sampling interval of 1000Km changed into atomic vapor in the heat after digesting with microwave. Hollow-cathode lamp made of the same element with metal content under test would radiate characteristic radiation with certain wavelength. A part of atomic vapor was launched with ground state atom after heating with graphite furnace. Concentration-absorbance working curve was finished with standard series sample after absorbance was measured. Finally, element content under test in oil was obtained based on the work curve. Database of primary element (Cu and Pb) content of lubricating oil in the same engine with different mileage was established. Results showed that Cu, Pb content fluctuates with different mileage in a certain range. In practical engineering applications, primary metal content in lubricating oil of engine crankshaft bearing was measured and compared with content variation trend chart. This new method not only helps automobile maintenance personnel to diagnose crankshaft bearing knock under no-disintegration situation but also is benefit for reducing the maintenance cost of automobile greatly and improving diagnostic accuracy of crankshaft bearing knock..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1683 (2014)
Spectroscopic Methods Applied to Component Determination and Species Identification for Coffee
CHEN Hua-zhou, XU Li-li, and QIN Qiang
Spectroscopic analysis was applied to the determination of the nutrient quality of ground, instant and chicory coffees. By using inductively coupled plasma atomic emission spectrometry (ICP-ES), nine mineral elements were determined in solid coffee samples. Caffeine was determined by ultraviolet (UV) spectrometry and oSpectroscopic analysis was applied to the determination of the nutrient quality of ground, instant and chicory coffees. By using inductively coupled plasma atomic emission spectrometry (ICP-ES), nine mineral elements were determined in solid coffee samples. Caffeine was determined by ultraviolet (UV) spectrometry and organic matter was investigated by Fourier transform infrared (FTIR) spectroscopy. Oxidation-reduction titration was utilized for measuring the oxalate. The differences between ground coffee and instant coffee was identified on the basis of the contents of caffeine, oxalate and mineral elements. Experimental evidence showed that, caffeine in instant coffee was 2-3 times higher than in ground coffee. Oxalate in instant coffee was significantly higher in ground coffee. Mineral elements of Mg, P and Zn in ground coffee is lower than in instant coffee, while Cu is several times higher. The mineral content in chicory coffee is overall lower than the instant coffee. In addition, we determined the content of Ti for different types of coffees, and simultaneously detected the elements of Cu, Ti and Zn in chicory coffee. As a fast detection technique, FTIR spectroscopy has the potential of detecting the differences between ground coffee and instant coffee, and is able to verify the presence of caffeine and oxalate..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1688 (2014)
Broadening Technique for Monte Carlo Simulated Element Characteristic X-Ray Spectrum
LI Zhe, TUO Xian-guo, and SHI Rui
In the present study, a kind of broadening algorithm method for simulated spectrum was developed by using the detector response function (DRF), which can be used to reduce the differences between Monte Carlo simulated element characteristic X-ray spectrum and experimental spectrum. First of all, based on in-depth studyIn the present study, a kind of broadening algorithm method for simulated spectrum was developed by using the detector response function (DRF), which can be used to reduce the differences between Monte Carlo simulated element characteristic X-ray spectrum and experimental spectrum. First of all, based on in-depth study on previous works of others, we established a kind of detector response function model with strong generality for Si-PIN semiconductor detector. Weighted nonlinear least-square method is used to fit the X-ray spectrum of standard single element, and parameters can be obtained simultaneously. Then these parameters are normalized to get the normalized response function R(E, E′), which will be used to broaden the simulated flux spectrum. Secondly, R(E, E′) is used to broaden and transform the simulated flux spectrum. Then pulse height spectrum (PHS) is obtained to match experiment spectrum. This procedure can obtain the X-ray spectrum conveniently only by using MCNP simulation; moreover, simulated spectrum and experimental spectrum have high consistency. Finally, the simulated spectrum was achieved to match the experimental spectrum. Ten elements (Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As and Sn) K doublet X-ray full energy peak was fitted by the proposed DRF model, and reduced chi-square values for each were in the range of 1.04～1.18. The simulated flux spectrum of a copper alloy sample containing six kinds of elements was transformed and matched the experimental spectrum really well, and the complex overlapped spectrum was resolved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1693 (2014)
Variation of Microfibril Angle in Dendrocalamus farinosus Analyzed Based on X-Ray Diffraction Spectrum and Its Effect on Tensile Properties
LIU Xing-e, YANG Xi, YANG Shu-min, TIAN Gen-lin, and SHANG Li-li
X-ray diffraction technology was used to rapidly predict variation in microfibril angle (MFA) in Dendrocalamus farinosus. The results show that there is little variation in MFA with bamboo age from 2a to 5a, and MFA of 3a is at the maximum with the value of 8.521°. The average value of MFA of 2a or 3a is greater tX-ray diffraction technology was used to rapidly predict variation in microfibril angle (MFA) in Dendrocalamus farinosus. The results show that there is little variation in MFA with bamboo age from 2a to 5a, and MFA of 3a is at the maximum with the value of 8.521°. The average value of MFA of 2a or 3a is greater than 4a or 5a with absolute differences less than 0.1°. MFA of base, middle and upper position respectively are 8.499°, 8.497° and 8.483° with coefficient of variation about 5%. There is an increasing tendency from the periphery to the inner of bamboo culms. Variance analysis indicates that MFA is highly sensitive to radial position, but insensitive to bamboo age and longitudinal position. The correlation coefficient of longitudinal strength and modulus of elasticity (MOE) is 0.57. MFA was responsible for 35% and 43% of the variation found in longitudinal strength and MOE respectively, which means MFA has a certain extent effect on mechanical properties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1698 (2014)
Compensation Method of Broadband Illuminant Fluctuation Based on Spectrum Linear Fitting
QIU Chao, SUN Xiao-gang, and LUAN Mei-sheng
The intensity of broadband illuminant fluctuates when its power supply output power changes. Spectral intensities at each wavelength within the band of broadband illuminant fluctuate at different levels. A method based on spectrum linear fitting is proposed to compensate the illuminant spectral intensity in its band whThe intensity of broadband illuminant fluctuates when its power supply output power changes. Spectral intensities at each wavelength within the band of broadband illuminant fluctuate at different levels. A method based on spectrum linear fitting is proposed to compensate the illuminant spectral intensity in its band when its intensity fluctuates. The spectral intensity fluctuation at each wavelength could be compensated simply by measuring the band intensity with this method. The linear relationship between spectral radiant exitance and whole radiant exitance of ideal blackbody was analysed by researching the radiant exitance at different temperatures. The linear model of broadband illuminant band intensity and spectral intensity was built. Experimental system is composed of a halogen light, a power supply, an aperture, a spectrometer, and a computer mainly. By adjusting the power output of the power supply, we obtained a set of halogen light relative spectral intensities at different power inputs. The spectral intensity of halogen light at different input powers was measured to test the compensation effect of this method. The relationship between spectral intensity and band intensity of halogen light was fitted with linear relation and the fitting errors were analysed. The experimental result shows a linear relationship between spectral intensity and band intensity of halogen light, so the spectral intensity fluctuation can be compensated using the band intensity according to their linear relation. The relative error absolute value of compensated spectral intensity decreases as the halogen light input power increases. Within the range of halogen light input power, the relative error absolute values of spectral intensity compensated with this method are within 5% at vast majority (92%) of the wavelengths..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1702 (2014)
Research on Outlier Detection Methods for Determination of Oil Yield in Oil Shales Using Near-Infrared Spectroscopy
ZHAO Zhen-ying, LIN Jun, and ZHANG Huai-zhu
In the present paper, the outlier detection methods for determination of oil yield in oil shale using near-infrared (NIR) diffuse reflection spectroscopy was studied. During the quantitative analysis with near-infrared spectroscopy, environmental change and operator error will both produce outliers. The presence of outIn the present paper, the outlier detection methods for determination of oil yield in oil shale using near-infrared (NIR) diffuse reflection spectroscopy was studied. During the quantitative analysis with near-infrared spectroscopy, environmental change and operator error will both produce outliers. The presence of outliers will affect the overall distribution trend of samples and lead to the decrease in predictive capability. Thus, the detection of outliers are important for the construction of high-quality calibration models. The methods including principal component analysis-Mahalanobis distance (PCA-MD) and resampling by half-means (RHM) were applied to the discrimination and elimination of outliers in this work. The thresholds and confidences for MD and RHM were optimized using the performance of partial least squares (PLS) models constructed after the elimination of outliers, respectively. Compared with the model constructed with the data of full spectrum, the values of RMSEP of the models constructed with the application of PCA-MD with a threshold of a value equal to the sum of average and standard deviation of MD, RHM with the confidence level of 85%, and the combination of PCA-MD and RHM, were reduced by 48.3%, 27.5% and 44.8%, respectively. The predictive ability of the calibration model has been improved effectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1707 (2014)
Development of a Portable Mid-Infrared Rapid Analyzer for Oil Concentration in Water Based on MEMS Linear Sensor Array
GAO Zhi-fan, ZENG Li-bo, SHI Lei, LI Kai, YANG Yuan-zhou, and WU Qiong-shui
Aiming at the existing problems such as weak environmental adaptability, low analytic efficiency and poor measuring repeatability in the traditional spectral oil analyzers, the present paper designed a portable mid-infrared rapid analyzer for oil concentration in water. To reduce the volume of the instrument, the non-sAiming at the existing problems such as weak environmental adaptability, low analytic efficiency and poor measuring repeatability in the traditional spectral oil analyzers, the present paper designed a portable mid-infrared rapid analyzer for oil concentration in water. To reduce the volume of the instrument, the non-symmetrical folding M-type Czerny-Turner optical structure was adopted in the core optical path. With a periodically rotating chopper, controlled by digital PID algorithm, applied for infrared light modulation, the modulating accuracy reached ±0.5%. Different from traditional grating-scanning spectrophotometers, this instrument used a fixed grating for light dispersion and avoided rotating error in the course of the measuring procedures. A new-type MEMS infrared linear sensor array was applied for modulated spectral signals detection, which improved the measuring efficiency remarkably. Optical simulation and experimental results indicate that the spectral range is 2 800～3 200 cm-1, the spectral resolution is 6 cm-1 (@3 130 cm-1), and the signal to noise ratio is up to 5 200∶1. The acquisition time is 13 milliseconds per spectrogram, and the standard deviation of absorbance is less than 3×10-3. These performances meet the standards of oil concentration measurements perfectly. Compared with traditional infrared spectral analyzers for oil concentration, the instrument demonstrated in this paper has many advantages such as smaller size, more efficiency, higher precision, and stronger vibration&moisture isolation. In addition, the proposed instrument is especially suitable for the environmental monitoring departments to implement real-time measurements in the field for oil concentration in water, hence it has broad prospects of application in the field of water quality monitoring..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1711 (2014)
Laser Speckle Suppression Due to Dynamic Multiple Scattering Scheme Introduced by Oblique Incidence
XU Mei-fang, GAO Wen-hong, SHI Yun-bo, WANG Hao-quan, and DU Bin-bin
Speckle suppression has been the research focus in laser display technology. In the present paper, the relation between multiple scattering and the size of speckle grains is established by analyzing the properties of speckle generated by the laser beam through SiO2 suspension. Combined with dynamic light scattering theSpeckle suppression has been the research focus in laser display technology. In the present paper, the relation between multiple scattering and the size of speckle grains is established by analyzing the properties of speckle generated by the laser beam through SiO2 suspension. Combined with dynamic light scattering theory, laser speckle suppression due to dynamic multiple scattering scheme introduced by oblique incidence is proposed. A speckle suppression element consists of a static diffuser and a light pipe containing the water suspension of SiO2 microspheres with a diameter of 300 nm and a molar concentration of 3.0×10-4 μm-3, which is integrated with the laser display system. The laser beam with different incident angles into the SiO2 suspension affecting the contrast of the speckle images is analyzed by the experiments. The results demonstrate that the contrast of the speckle image can be reduced to 0.067 from 0.43 when the beam with the incident angle of approximately 8° illuminates into the SiO2 suspension. The spatial average of speckle granules and the temporal average of speckle images were achieved by the proposed method, which improved the effect of speckle suppression. The proposed element for speckle suppression improved the reliability and reduced the cost of laser projection system, since no mechanical vibration is needed and it is convenient to integrate the element with the existing projection system..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1716 (2014)
Research on High Sensitivity Temperature Sensor Based on Mach-Zehnder Interferometer with Waist-Enlarged Fiber Bitapers
ZHAO Na, FU Hai-wei, SHAO Min, LI Hui-dong, LIU Ying-gang, and QIAO Xue-guang
Optical fiber sensing technology is one of the very promising techniques in sensing fields. A high sensitivity high temperature sensor based on inline optical fiber Mach-Zehnder(M-Z) interferometer by using standard single mode fiber with two waist-enlarged bitapers is proposed in the present paper. The waist-enlarged Optical fiber sensing technology is one of the very promising techniques in sensing fields. A high sensitivity high temperature sensor based on inline optical fiber Mach-Zehnder(M-Z) interferometer by using standard single mode fiber with two waist-enlarged bitapers is proposed in the present paper. The waist-enlarged bitapers are considered as couplers, the distance between the two bitapers is the sensing arm. The light in the lead-in fiber core couples into the sensing arms’ fiber core and cladding by the first bitaper, and then propagate in them. The phase difference between core mode and cladding mode is produced when the light reaches the second bitaper. Then the second bitaper couples the light into the lead-out single-mode fiber to get the interference spectrum. The sensors with different length were fabricated. The relationship between the sensor length and interference period, and the temperature response of the sensor were studied by experiments. The results show that the 35 mm long sensor has a high sensitivity of 0.115 nm·℃-1 in the range of 30～400 ℃. The transmission spectrum of the sensor was also analyzed by the fast Fourier transform. It shows that only LP01 mode and LP08 mode propagate in the sensor. The sensor has advantages of small size, high precision, and immunity to electromagnetic inteference. In addition, it is of easy fabrication, high signal-to-noise ratio, light weight, and high sensitivity, and could be operated under high temperature. This kind of sensor is a good candidate for high temperature measurement of hot gas, oil and gas well logging and other areas..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1722 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1 (2014)
Research Articles
The Research on Residual Amplitude Modulation Characteristics in Fiber Frequency Modulation Spectroscopy
FU Xiao-fang, ZHAO Gang, MA Wei-guang, TAN Wei, LI Zhi-xin, DONG Lei, ZHANG Lei, YIN Wang-bao, and JIA Suo-tang
Frequency modulation spectroscopy (FMS) not only can be used to simultaneously measure the absorption and dispersion of atoms and molecules, but is the key technology of the noise immunity cavity enhanced optical heterodyne molecular spectroscopy(NICE-OHMS). The optical devices or the instability of output light polariFrequency modulation spectroscopy (FMS) not only can be used to simultaneously measure the absorption and dispersion of atoms and molecules, but is the key technology of the noise immunity cavity enhanced optical heterodyne molecular spectroscopy(NICE-OHMS). The optical devices or the instability of output light polarization of the laser source will induce the residual amplitude modulation (RAM) in the FMS. RAM greatly limits the FMS technology application in trace gas detection, so the research on the RAM characteristics in the FMS has very important significance. Firstly, the lineshape of FMS without absorption was analyzed, and the impact factors on the RAM were acquired, then the influence of input and output polarization direction and electro-optical modulation (EOM) temperature was measured, respectively. They all have linear relationship with the RAM. The results verify the theoretical analysis and provide the basis for reducing the RAM and other related working..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1456 (2014)
Differentiated Fluorescence Centers in Europium Acetylacetonate Hydrate Doped Poly Methyl Methacrylate
ZHANG Yang-yang, ZHONG Hua, CHEN Bao-jiu, XIA Ying, and LIN Hai
Poly methyl methacrylate (PMMA) was doped with europium acetylacetonate hydrate. Judd-Ofelt parameters Ω2 (19.73×10-20 cm2) and Ω4 (2.19×10-20 cm2) indicate a high inversion asymmetry and strong covalent environment around Eu3+ in PMMA. The maximum stimulated emission cross-sections for the 5D0→7FJ(J=1, 2 andPoly methyl methacrylate (PMMA) was doped with europium acetylacetonate hydrate. Judd-Ofelt parameters Ω2 (19.73×10-20 cm2) and Ω4 (2.19×10-20 cm2) indicate a high inversion asymmetry and strong covalent environment around Eu3+ in PMMA. The maximum stimulated emission cross-sections for the 5D0→7FJ(J=1, 2 and 4) transitions in EAH doped PMMA were calculated to be 0.38×10-21, 4.90×10-21 and 0.36×10-21 cm2, respectively. Efficient purplish-red and red fluorescence was obtained from europium acetylacetonate hydrate doped PMMA under 365 and 254 nm excitation respectively, indicating that it can be used as UV sensitive components for fiber optic sensors. Because of the suitable refractive index difference between doped sample and pure PMMA, it is expected to fabricate standard 9 μm/125 μm optical fiber which supports multi-mode transmission, providing basis of further development for medical fiber, flexible communication fiber and fiber optic sensor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 6, 1482 (2014)
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