Journals >Spectroscopy and Spectral Analysis
Contents
2012
Volume: 32 Issue 4
65 Article(s)
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Research Article
Studies on the Q-Branch Spectral Lines of High-Lying Rovibrational Transitions of Diatomic System
FU Jia, SUN Wei-guo, LI Hui-dong, FAN Qun-chao, ZHANG Yi, and FENG Hao
An analytical formula was proposed recently to predict the accurate P-branch spectral lines of rovibrational transitions for diatomic systems by taking multiple spectral differences. A similar analytical expression was suggested here to predict the Q-branch spectral lines of rovibrational transitions. This formula was An analytical formula was proposed recently to predict the accurate P-branch spectral lines of rovibrational transitions for diatomic systems by taking multiple spectral differences. A similar analytical expression was suggested here to predict the Q-branch spectral lines of rovibrational transitions. This formula was applied to study the high-lying Q-branch emission spectra of the (4,1) and (3,1) bands of the A1Π—X1Σ+ system of IrN molecule using fifteen known accurate experimental transition data. The results show that not only the known experimental transition lines were reproduced but also the correct values of the unknown spectral lines were predicted..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 865 (2012)
Theoretical Study of the Influence of Different Substituents on the Electron-Photon Spectra of Quinoline
XU Liang, LIU Hong-jie, ZHOU Xin-da, JIANG Xiao-dong, CHEN Shan-jun, CHEN Shi-juan, and WU Wei-dong
Different substituents result in different changes in electron-photon spectra, and to reveal the relationship between substituents and spectra, a theoretical investigation was elaborated via quantum chemical calculations. Density functional theory and single excitation configuration interaction were respectively employDifferent substituents result in different changes in electron-photon spectra, and to reveal the relationship between substituents and spectra, a theoretical investigation was elaborated via quantum chemical calculations. Density functional theory and single excitation configuration interaction were respectively employed in optimizing geometric and electronic structures of ground and excited states, and the absorption and emission spectra were studied by time-dependent density functional theory methods. The results show that all the different substituents bring on different geometric and electronic structures of ground and excited states, different energies of frontier molecular orbitals as well as different π-conjugated systems, the spectra change with all the differences，and relationships are brought out in this paper, which gives theoretical reference for identifying different derivatives from electron-photon spectra..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 871 (2012)
Research on the Analytical Line Auto-Selection for Quantitative Analysis of Materials with Laser-Induced Breakdown Spectroscopy
DU Zhen-hui, MENG Fan-li, LI Jin-yi, MA Yi-wen, SUN Lan-xiang, CONG Zhi-bo, and XIN Yong
To realize auto-selection of analytical lines for quantitative analysis of materials with laser-induced breakdown spectroscopy, two parameters, i.e. the relative detected-to-theory intensity ratio (RDTIR) and wavelength difference of detected and theory (WDDT) were defined. The spectral lines seriously disturbed by selTo realize auto-selection of analytical lines for quantitative analysis of materials with laser-induced breakdown spectroscopy, two parameters, i.e. the relative detected-to-theory intensity ratio (RDTIR) and wavelength difference of detected and theory (WDDT) were defined. The spectral lines seriously disturbed by self-absorption and spectral interference were excluded automatically by setting reasonable thresholds of RDTIR and WDDT. By analyzing the experimental data of high-alloy steel (GBW01605), the analytical lines of iron (Fe), chromium (Cr), nickel (Ni), manganese (Mn) and copper (Cu) were selected, and the results were in line with the principle of lines selection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 876 (2012)
The Study on the Laser-Induced Breakdown Spectroscopy Properties of Compound Fertilizer with Different Physical Forms
LI Jun, LU Ji-dong, YAO Shun-chun, and DONG Mei-rong
In order to study the mechanism of laser-induced breakdown spectroscopy for detecting the chemical components content of compound fertilizer in detail, two physical forms of compound fertilizer samples (powder and granular) were used for this study. The authors analyzed the laser-induced breakdown spectroscopy propertiIn order to study the mechanism of laser-induced breakdown spectroscopy for detecting the chemical components content of compound fertilizer in detail, two physical forms of compound fertilizer samples (powder and granular) were used for this study. The authors analyzed the laser-induced breakdown spectroscopy properties of samples with different physical forms made under different preparation pressure. And the spectral characteristics and plasma characteristics of N，P and K in the powder and granules made under the preparation pressure of 0, 0.5, 2, 4, and 6 MPa, respectively were compared experimentally. The experiments results showed that the spectral characteristics of the two forms have obvious difference when the pressure is small and the grain samples have significant higher line intensity than those of the powder samples. With the increase in the pressure, the difference in the plasma characteristics between these two physical forms was reduced, and all the characteristic spectral lines intensity of the same physical form samples increases firstly and reduces afterward..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 881 (2012)
Study of Characteristics of Excited O Atom Generated in Multi-Needle-to-Plate Corona Discharge by Emission Spectroscopy
GE Hui, YAN Ling, MI Dong, ZHU Yi-min, and ZHANG Lu
The emission spectra of O(3p5P→3s5S02 777.4 nm) produced by multi-needle-to-plate negative corona discharge and positive streamer discharge in air were successfully recorded at one atmosphere. The influences of discharge power, electrode gap, content of N2 and relative humidity on the excited O atom production were invThe emission spectra of O(3p5P→3s5S02 777.4 nm) produced by multi-needle-to-plate negative corona discharge and positive streamer discharge in air were successfully recorded at one atmosphere. The influences of discharge power, electrode gap, content of N2 and relative humidity on the excited O atom production were investigated in negative corona discharge. Meanwhile, the distribution of relative density of excited O atom in discharge space was also studied in positive streamer discharge. The results indicate that, for negative corona discharge, the amount of O active atom increases with the increase in power, decreases with increased discharge gap. And with the increase in relative humidity and N2 content, its amount firstly increases and then decreases; whereas for positive corona discharge, the relative density of O active atom from needlepoint to plate firstly increases and then decreases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 886 (2012)
Spectral Intensity Distribution of Oxygen Atom in a Plasma Plume
LI Xue-chen, JIA Peng-ying, YUAN Ning, and YANG Bao-zhu
Low temperature plasma generated in plasma plume discharge at atmospheric pressure has prosperous application fields in industry because the vacuum device can be dispensable and some complex materials can be treated in three dimensions by this plasma plume. A stable plasma plume was generated in atmospheric pressure aiLow temperature plasma generated in plasma plume discharge at atmospheric pressure has prosperous application fields in industry because the vacuum device can be dispensable and some complex materials can be treated in three dimensions by this plasma plume. A stable plasma plume was generated in atmospheric pressure air in the present paper by using a plasma needle discharge device. It was found by spectral measurement that there are some spectral lines emitted from oxygen atom such as 777.5 and 844.6 nm in the optical emission spectra of the plasma plume. This phenomenon indicates that oxygen atom with high chemical activity was generated in the air discharge at atmospheric pressure. The spatial distribution of the spectral intensity from the oxygen atom was investigated by spectroscopic method. Results show that the spectral intensity from oxygen atom near the needle electrode was much higher than that in other regions. In order to explain this experimental phenomenon, spatial-resolved signals emitted from the plume were detected by using photomultiplier tubes. It was found that the width of light pulse near the needle electrode was much bigger than that in other regions. These results are important for the application of plasma plume in industry such as sterilization and disinfection fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 890 (2012)
Retrieval of NO2 Total Vertical Columns by Direct-Sun Differential Optical Absorption Spectroscopy
WANG Yang, XIE Pin-hua, LI Ang, XU Jin, ZENG Yi, SI Fu-qi, and WU Feng-cheng
An appropriate reference spectrum is essential for the direct-sun differential optical absorption spectroscopy (DS-DOAS). It depends on the real reference spectrum to retrieve the total vertical column density (VCD). The spectrum detected at the time with minimum sun zenith angle under the relative clear atmospheric coAn appropriate reference spectrum is essential for the direct-sun differential optical absorption spectroscopy (DS-DOAS). It depends on the real reference spectrum to retrieve the total vertical column density (VCD). The spectrum detected at the time with minimum sun zenith angle under the relative clear atmospheric condition in the measurement period was conventionally selected as the reference spectrum. Because there is still untracked NO2 absorption structure in the reference spectrum, the VCD retrieved based on the above spectrum is actually relative VCD, which results in larger error. To solve this problem, a new method was investigated. A convolution of extraterrestrial high-precision solar Fraunhofer spectrum and the instrumental function of the spectrometer was computed and chosen as the reference spectrum. The error induced by NO2 absorption structure in the reference spectrum was removed. Then the fitting error of slant column density (SCD) retrieved by this method was analyzed. The correlation between the absolute SCD and the differential slant column density (dSCD) was calculated. The result shows that the error of SCD retrieved by this new method is below 1.6×1016 molecules·cm-2 on March 7, 2011, while the error generated by the normal method is about 4.25×1016 molecules·cm-2. The new method decreased more than 62% error. In addition, the results throughout the day were compared to the troposphere VCD from MAX-DOAS and they are in good agreement. It indicates that the new method could effectively reduce the VCD error of the common way..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 893 (2012)
Spectroscopic Measurement of Intermediate Free Radicals of n-Heptane in the Combustion Reaction
YE Bin1, LI Ping1*, ZHANG Chang-hua1, WANG Li-dong1, TANG Hong-chang1, and LI Xiang-yuan
Using an intensified spectroscopic detector CCD and a chemical shock tube, transient emission spectra of n-heptane during the reaction process of combustion were measured, with exposure time of 6 μs and a spectral range of 200~850 nm. Experiments were conducted at an ignition temperature of 1 408 K and pressure of 2.0 Using an intensified spectroscopic detector CCD and a chemical shock tube, transient emission spectra of n-heptane during the reaction process of combustion were measured, with exposure time of 6 μs and a spectral range of 200~850 nm. Experiments were conducted at an ignition temperature of 1 408 K and pressure of 2.0 atmos, with an initial fuel mole fraction of 1.0% and an equivalence ratio of 1.0. Measured emission bands were determined to be produced by OH, CH and C2 free radicals, which reveals that small OH, CH and C2 radicals are important intermediate products in the combustion process of n-heptane. Time-resolved spectra indicate that radical concentrations of OH, CH and C2 reached their peaks sharply; however, CH and C2 reduced and disappeared rapidly while the duration of OH was much longer in the reaction. This work provides experimental data for understanding the microscopic process and validating the mechanism of n-heptane combustion reaction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 898 (2012)
Based on THz Spectroscopy Detection Method for the Concentration of 1,3-Dinitrobenzene Volatile Gas
ZHAO Hui, WANG Gao, and MA Tie-hua
For the unexpected situations occur that 1,3-dinitrobenzene volatile gas leaks in industrial production process, designed the differential characteristics absorption detection system for 1,3-dinitrobenzene volatile gas based on THz spectrum technique. The method can detect the concentration of trace 1,3-dinitrobenzene For the unexpected situations occur that 1,3-dinitrobenzene volatile gas leaks in industrial production process, designed the differential characteristics absorption detection system for 1,3-dinitrobenzene volatile gas based on THz spectrum technique. The method can detect the concentration of trace 1,3-dinitrobenzene toxic gases through the THz characteristic wavelengths differential absorption method. System dealt with THz characteristics wavelengths of the two chambers, which provide difference dates, a group is standard air, and the other group tested the sample gas. Four main absorption bands of 1,3-dinitrobenzene is at 0.635, 0.912, 1.095 and 1.435 THz nearby in detection results, and according to the ratio of absorption coefficient in the corresponding absorption band it calculated the accurate amplitude from the corresponding wavelengths, at last the gas concentration was inversed. After the two traditional methods (chromatography and infrared absorption method) of experimental analysis and THz absorption detection method of the simulation study shows, precision of the detection capabilities of chromatography is high and error is small. But the chromatography separation time varies with the material, long cycle, slow; chromatography can not achieve real-time detection speed to realize real-time detection. Infrared absorption of environmental humidity is high, subject to drying. At the same time, THz absorption of environmental humidity is low; THz absorption method also has important characteristics of real time, strong anti-jamming, especially the water vapor, so it is more suitable for practical application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 902 (2012)
Far-IR and THz Absorption Spectra Studies of Metronidazole, Tinidazole and Ornidazole
ZHANG Zhen-wei, ZUO Jian, and ZHANG Cun-lin
Metronidazole, tinidazole and ornidazole are 5-nitro-imidazole medicines used particularly for anaerobic bacteria and protozoa infections. The present paper reports that terahertz time-domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy (Far-FTIR) were used to measure the fingerprint spectra of meMetronidazole, tinidazole and ornidazole are 5-nitro-imidazole medicines used particularly for anaerobic bacteria and protozoa infections. The present paper reports that terahertz time-domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy (Far-FTIR) were used to measure the fingerprint spectra of metronidazole, tinidazole and ornidazole in the frequency range of 0.9~19.5 THz under the room temperature. In addition, THz-TDS was also used to measure the absorption spectra of pure tinidazole and tinidazole tablets from different manufactures between 0.2 and 2.2 THz. In parallel with the experimental study, the cross correlation analysis was applied to compare the array of correlation coefficients between pure tinidazole and different tinidazole tablets. Results show that the method is rapid, simple and accurate to identify their effective chemical compositions and stability when the FTIR and THz spectra data combine with the array of correlation coefficient. Our research provides a visual approach to the standardization and modernization of the quality control in the production and sale of such drugs..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 906 (2012)
Study on Wavelength Locking Technology in Trace Gases Detection System Based on Laser Techniques
WANG Li-ming, ZHANG Yu-jun, HE Ying, YOU Kun, LIU Jian-guo, and LIU Wen-qing
In the trace gases detection system with tunable diode laser absorption spectroscopy (TDLAS) technology, the measurement of trace gases concentration was influenced by the laser wavelength drift resulting from the change in ambient temperature and noise of laser control electronics. With open-path TDLAS ammonia concentIn the trace gases detection system with tunable diode laser absorption spectroscopy (TDLAS) technology, the measurement of trace gases concentration was influenced by the laser wavelength drift resulting from the change in ambient temperature and noise of laser control electronics. With open-path TDLAS ammonia concentration detection system as an example, in the present paper the scanning law of laser center wavelength with current was analyzed, and the adaptive locking method of scanning laser center wavelength was presented based on controlling laser current. The aligning algorithm of measurement spectroscopy with calibration reference spectroscopy was studied. The open-path ammonia concentration was achieved in real time. Experiment results show that the precision and the stability of retrieving the concentration of trace gases were improved satisfactorily by wavelength locking. The variation of ammonia concentration has an obvious diurnal periodicity, which increased in rush hour time and got to the maximum at noon, then decreased at night. The system detection limit is about 3.8 mg·m-3·m..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 910 (2012)
Research on and Application of Hybrid Optimization Algorithm in Brillouin Scattering Spectrum Parameter Extraction Problem
ZHANG Yan-jun, ZHANG Shu-guo, FU Guang-wei, LI Da, LIU Yin, and BI Wei-hong
This paper presents a novel algorithm which blends optimize particle swarm optimization (PSO ) algorithm and Levenberg-Marquardt (LM) algorithm according to the probability. This novel algorithm can be used for Pseudo-Voigt type of Brillouin scattering spectrum to improve the degree of fitting and precision of shift exThis paper presents a novel algorithm which blends optimize particle swarm optimization (PSO ) algorithm and Levenberg-Marquardt (LM) algorithm according to the probability. This novel algorithm can be used for Pseudo-Voigt type of Brillouin scattering spectrum to improve the degree of fitting and precision of shift extraction. This algorithm uses PSO algorithm as the main frame. First, PSO algorithm is used in global search, after a certain number of optimization every time there generates a random probability rand(0, 1). If rand(0, 1) is less than or equal to the predetermined probability P, the optimal solution obtained by PSO algorithm will be used as the initial value of LM algorithm. Then LM algorithm is used in local depth search and the solution of LM algorithm is used to replace the previous PSO algorithm for optimal solutions. Again the PSO algorithm is used for global search. If rand(0, 1) was greater than P, PSO algorithm is still used in search, waiting the next optimization to generate random probability rand(0, 1) to judge. Two kinds of algorithms are alternatively used to obtain ideal global optimal solution. Simulation analysis and experimental results show that the new algorithm overcomes the shortcomings of single algorithm and improves the degree of fitting and precision of frequency shift extraction in Brillouin scattering spectrum, and fully prove that the new method is practical and feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 915 (2012)
Infrared Spectroscopy Investigation on Conformational Change of Silk Fiber Induced by Gaseous Organic Acids Existing in Museum
LUO Xi-yun, MA Wen-ting, WU Jin-qing, GENG Jin-pei, LI Xiao-yu, LI Xiu-yong, and DU Yi-ping
Study on the impact of pollutants on cultural materials in storing or displaying micro-environment in museum is considered as very important for the preservation of cultural relics and its aging prevention. This paper applied the Fourier transform infrared (attenuated total reflection) technique to assess silk structurStudy on the impact of pollutants on cultural materials in storing or displaying micro-environment in museum is considered as very important for the preservation of cultural relics and its aging prevention. This paper applied the Fourier transform infrared (attenuated total reflection) technique to assess silk structural changes under volatile organic acids (formic acid/acetic acid)， which usually come from decorative materials emission and commonly exist in the surface or around cultural materials. The focus of this work was on investigating the changes of peptide bond in the area of amide Ⅰ-amide Ⅲ , as well as the peptide chains (GlyAla)n characteristic region. The structural and conformational changes in silk fiber treated with gaseous formic and acetic acid were assessed. The results indicate that both the gaseous acids can weaken the intermolecular hydrogen bond in fiber peptide, based on the spectral changes in the increased intensity of amide Ⅰ (1 617 cm-1) , the narrowing amide Ⅱ peak (1 515 cm-1), the increased intensity of random coil conformation in amide Ⅲ peak (1 230 cm-1), and the decreased fiber crystallinity as well. The obvious secondary structural conformation occurred when the concentration of gaseous formic acid reached 8.1 mg·m-3 in simulated environment. The conformational transformation was supported by the observation of the rapidly reduced random coil conformation, the increased short peptide chains (GlyAla)n with β-sheet conformation characteristic peak (1 000, 975 cm-1), and the enhanced fiber crystallinity degree as well. In contrast, gaseous acetic acid has less impact on the amide Ⅰ and amide Ⅱ bond based on the spectral changes, but it did promote random coil conformation and decreased fiber crystallinity. This work also provides a potential application of the infrared spectroscopy in non-destructive investigation of silk in-situ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 921 (2012)
Research on Identification of American Ginseng and Panax Ginseng by Near Infrared Spectra of Samples’ Cross Section
WANG Ling-ling, HUANG Ya-wei, QI Shu-ye, Jacqueline J SHAN, Lei LING, and HAN Dong-hai
In order to identify American ginseng and panax ginseng samples accurately and rapidly, the authors acquired the NIR spectra of the samples’ cross-sections. Then the spectra were respectively analyzed according to the samples’ physical structure factors and chemical factors. The authors selected appropriate bands and bIn order to identify American ginseng and panax ginseng samples accurately and rapidly, the authors acquired the NIR spectra of the samples’ cross-sections. Then the spectra were respectively analyzed according to the samples’ physical structure factors and chemical factors. The authors selected appropriate bands and built a physical factor leading model, a chemical factors leading model as well as a comprehensive factor model. The authors found that all the three models’ discriminant rates were above 96 percents, which can meet the needs of the rapid detection of raw Chinese medicinal crop materials. While the physical factors model had a simple operation, the discriminant rate was relatively low. The chemical factors model’ discriminant rate was higher, but the computation is much more complex. Among the three models, the mixed factor model had the best result with the highest discrimination rate (100 percents) and a smaller number of principal components (4). The effect was the most ideal. It proved that physical factors play an important part in NIR modeling. The cross section method is accurate and convenient which can be used in the quality control in enterprise, realizing the rapid screening of the medicine raw materials..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 925 (2012)
Effect of Path-Length Variations on PLSR Calibration Model in Noninvasive Measurement of Blood Glucose by Mid-Infrared Spectroscopy
WANG Dong-min, LU Qi-peng, DING Hai-quan, and HUANG Fu-rong
In noninvasive blood glucose measurement, it is difficult to keep the contact area between skin and internal reflectance element uniform while the mid-infrared spectra of human skin are taken, and this would lead to path-length variations. To study the effect of path-length variations on PLSR calibration model, in the In noninvasive blood glucose measurement, it is difficult to keep the contact area between skin and internal reflectance element uniform while the mid-infrared spectra of human skin are taken, and this would lead to path-length variations. To study the effect of path-length variations on PLSR calibration model, in the present paper, according to the correlation coefficients between path-lengths and glucose concentrations, two PLSR models were achieved respectively and RMSECV were 31.3 and 4.52 mg·dL-1, RMSEP were 30.3 and 98.7 mg·dL-1 for the validation set. The results show that the chance correlations between path-lengths and glucose concentrations will lead to calibration models with different accuracy and robustness. This is useful to improving the reliability of noninvasive measurement of blood glucose by mid-infrared spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 930 (2012)
Study of Chance Correlation in Blood Glucose Sensing
ZHAO Bo, CAO Yu-zhen, LIU Rong, and XU Ke-xin
In the noninvasive blood glucose sensing by the near-infrared spectroscopy, chemometrics is applied to achieve the quantitative analysis of unknown samples. In modeling and validation process, however, there usually introduces a certain degree of chance correlation, thus affecting the stability of the model. In the preIn the noninvasive blood glucose sensing by the near-infrared spectroscopy, chemometrics is applied to achieve the quantitative analysis of unknown samples. In modeling and validation process, however, there usually introduces a certain degree of chance correlation, thus affecting the stability of the model. In the present paper, normally distributed random numbers were used to simulate spectral data and reference concentration. In this way, it can investigate the probability level of chance correlation from the number of selected modeling wavelengths and different probable cross validation methods. Chance correlation exists in the process of modeling. In this paper, there has also given the best level of modeling wavelengths and the optimal cross validation method to reduce the chance correlation. In addition, the in vitro experiment of glucose aqueous solution at different temperature is conducted. In this experiment, the relationship between the temperature and the glucose concentration was obtained, according to which the temperature effect in practice was reduced..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 934 (2012)
Study of Feature Extraction Methods for Maize’s Near Infrared Spectra in Biomimetic Pattern Recognition
SHEN Li-feng, JIA Shi-qiang, GUO Ting-ting, WU Wen-jin, YAN Yan-lu, and AN Dong
Near infrared spectrum is an important step in near infrared spectrum qualitative analysis, which influences the qualitative analysis results directly. Diffuse transmittance measurements mode was used to collect spectral data of eight maize varieties. PCA, ICA, PLS-DA and wavelet transformation were used to extract feaNear infrared spectrum is an important step in near infrared spectrum qualitative analysis, which influences the qualitative analysis results directly. Diffuse transmittance measurements mode was used to collect spectral data of eight maize varieties. PCA, ICA, PLS-DA and wavelet transformation were used to extract features of pretreated data. Finally, we used the test set data to test the recognition models of eight maize varieties which were built based on biomimetic pattern recognition (BPR). We draw a conclusion that PLS-DA can make models get higher average correct recognition rate than PCA, ICA and Wavelet transformation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 939 (2012)
Analysis of Pyrolysis Process and Gas Evolution Rule of Larch Wood by TG-FTIR
REN Xue-yong, DU Hong-shuang, WANG Wen-liang, GOU Jin-sheng, and CHANG Jian-min
The weight-loss character and gas evolution rule of larch wood at different heating rates were investigated by TG-FTIR (thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer), and the results were compared with those of larch wood model-component mixture. The main weight-loss area of larch wooThe weight-loss character and gas evolution rule of larch wood at different heating rates were investigated by TG-FTIR (thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer), and the results were compared with those of larch wood model-component mixture. The main weight-loss area of larch wood was wider than larch wood model-component mixture, and the residual char yield of larch wood (18.97%) was lower than larch wood model-component mixture (29.83%). During the pyrolysis process, the activation energy of larch wood model-component mixture was higher than the larch wood’s in the low-temperature region, but there was little difference between the two segments in high temperature region. Larch wood came through several stages of water extraction, main component decomposition, charring during its pyrolysis process, and gas precipitation mainly happening at near 375 ℃. The order of main gas products generated from the larch wood pyrolysis reaction was CO2>H2O>CH4>CO, and the gas product yield was significantly increased when the heating rate increased. The larch wood model-component mixture had the similar basic rules of producing gas to larch wood, but the former had relatively higher precipitation density than the latter..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 944 (2012)
Determination of Sodium by Near Infrared Spectroscopy
CHEN Jian-hong, ZHU Ling-jian, and HUA Deng-xin
The research on near infrared spectroscopy of sodium in biological and medicine is significant. Sodion is the main component of electrolytes in human blood and electrolytes help maintain the body’s acid-base balance. In the present paper the concentration of sodium was determined with the use of NIR spectra. On the basThe research on near infrared spectroscopy of sodium in biological and medicine is significant. Sodion is the main component of electrolytes in human blood and electrolytes help maintain the body’s acid-base balance. In the present paper the concentration of sodium was determined with the use of NIR spectra. On the basis of NIR spectroscopic measurement mechanism of sodion, prediction models of the concentration of sodium were developed with linear regression using the absorbance at selected wavelengths. In order to reduce temperature perturbations to water bands with the measurement of sodium, Partial least squares regression (PLS) was adopted using select spectra area. The result shows that the determination coefficients (R2)=99.82%， the root mean square error of cross validation (RMSECV)=14.5, and the residual prediction deviation (RPD)=23.7, for the calibration model. It meets the daily requirements of biochemical detection accuracy. This technique can be applied to quantitative analysis of sodion in the hospital laboratory..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 949 (2012)
Investigation of FTIR Spectra Analysis of Gallstones from Xuzhou Region by Solvent Extraction
YIN Wen-xuan, WANG Jing, ZHANG Nan, WANG Jian-huai, BAO Ya-xing, SUN Cun-jie, and LI Zhuang-fu
The present paper is a preliminary exploration of the possible way the gallstones are formed. Five categories of gallstones from clinical surgery in Xuzhou region were extracted by a series of solvents. Fourier transform infrared spectroscopy (FTIR) was used to characterize the structure of morphological changes betweeThe present paper is a preliminary exploration of the possible way the gallstones are formed. Five categories of gallstones from clinical surgery in Xuzhou region were extracted by a series of solvents. Fourier transform infrared spectroscopy (FTIR) was used to characterize the structure of morphological changes between gallstone and residue by extracting. The gallstone samples are from clinical surgeries in Xuzhou region where gallstone disease is quite common. Samples were extracted with a series of solvents, and then FTIR and other instrumental analysis were applied to characterize the composition, structure and morphological changes of the samples both before and after the extraction. The results show that the gallstone samples can be classified as 5 types: cholesterol-type, cholesterol-based hybrid type with salt, bilirubin and protein as its insoluble substances, brown pigment type and black pigment type gallstones. The results also indicate that protein plays a key role in gallstone nucleation process by providing a sediment matrix for the formation of gallstones. Both cholesterol and carbonated hydroxyapatite are found in the insoluble substances of the samples. It is possible that cholesterol was accompanied by carbonated hydroxyapatite and there are interactions between them, and these interactions contribute to the crystallization process and speed up the formation of gallstones. All the results above may provide useful references for the clinical diagnosis, treatment and prevention of gallstones..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 953 (2012)
Rapid Determination of Sudan Dyes Adulterated in Natural Paprika Red by FTIR
ZHANG Wei-wei, LIU Ling-ling, WU Yan-wen, OUYANG Jie, and SUN Su-qin
How to rapidly determine synthesized pigments or dyes adulterated in natural pigments is a difficult problem for food analysts. Natural paprika red is widely used in foods because of its coloration and pharmaceutical effect, but it is sometimes adulterated with Sudan dyes for its poor stability under light or heat treaHow to rapidly determine synthesized pigments or dyes adulterated in natural pigments is a difficult problem for food analysts. Natural paprika red is widely used in foods because of its coloration and pharmaceutical effect, but it is sometimes adulterated with Sudan dyes for its poor stability under light or heat treatment. In the present paper, the macro-fingerprint characteristic of infrared spectroscopy was utilized to identify Sudan dyes adulterated in paprika red. The strong peaks at 1 621, 1 500 and 751 cm-1 in FTIR spectra and at the fingerprint region of 753, 684 and 496 cm-1 in the secondary deriative FTIR spectra were remarkable characteristics for Sudan dyes adulterated in paprika red, of which the limit of determination was about 1%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 958 (2012)
The Detection of Hatching Eggs Prior to Incubation by the Near Infrared Spectrum
ZHU Zhi-hui, WANG Qiao-hua, WANG Shu-cai, DAI Ming-yu, and MA Mei-hu
The detection of the infertile eggs and fertile eggs by the near infrared diffuse reflectance spectra was proposed. Models based on different band regions range, different principal component numbers and the different spectral pre-processing methods were compared and the optimal calibration model was established. The rThe detection of the infertile eggs and fertile eggs by the near infrared diffuse reflectance spectra was proposed. Models based on different band regions range, different principal component numbers and the different spectral pre-processing methods were compared and the optimal calibration model was established. The results show that qualitative forecasting model of hatching eggs is established by Mahalanobis Distance, which is with band regions range being 4 119.20～9 881.46 cm-1, principal component number being 19 and spectral pre-processing method being SNV+first derivative+Norris differential filter. The precision rate of calibration set is 92.5% and that of validation set is 91.67%. The study provides a new way for nondestructive testing of the fertile eggs and infertile eggs prior to incubation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 962 (2012)
Discrimination of Different Aging Methods of Grape Wine Based on ATR Infrared Spectroscopy
TANG Jian-bo, LI Jing-ming, LI Jun-hui, ZHAO Long-lian, ZHANG Ye-hui, and ZHANG Lu-da
A total of 96 red wines aged with 3 kinds of methods were included in this study, including 44 wines aged in oak barrel, 26 wines aged in stainless steel tank added with oak chips and 26 wines aged in stainless steel tanks. The infrared spectra of the wines were scanned by Fourier transform infrared spectrometer with aA total of 96 red wines aged with 3 kinds of methods were included in this study, including 44 wines aged in oak barrel, 26 wines aged in stainless steel tank added with oak chips and 26 wines aged in stainless steel tanks. The infrared spectra of the wines were scanned by Fourier transform infrared spectrometer with attenuated total reflection (ATR) accessories. To classify the 96 different aged wines, discriminant partial least squares (DPLS) method and support vector machine (SVM) method were used to establish models respectively. In order to examine the stability of the discriminant model, modeling was repeated 10 times with two-thirds of samples randomly selected as cross-validation. All the models had high discriminating power with the classification accuracy of the cross-validation and the validation all higher than 90%. These results suggest that the infrared ATR spectroscopy combined with pattern recognition method is a promising tool for discriminating different aging wines..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 966 (2012)
Determination of Process Variable pH in Solid-State Fermentation by FT-NIR Spectroscopy and Extreme Learning Machine (ELM)
LIU Guo-hai, JIANG Hui, XIAO Xia-hong, ZHANG Dong-juan, MEI Cong-li, and DING Yu-han
Fourier transform near-infrared (FT-NIR) spectroscopy was attempted to determine pH, which is one of the key process parameters in solid-state fermentation of crop straws. First, near infrared spectra of 140 solid-state fermented product samples were obtained by near infrared spectroscopy system in the wavelength rangeFourier transform near-infrared (FT-NIR) spectroscopy was attempted to determine pH, which is one of the key process parameters in solid-state fermentation of crop straws. First, near infrared spectra of 140 solid-state fermented product samples were obtained by near infrared spectroscopy system in the wavelength range of 10 000～4 000 cm-1, and then the reference measurement results of pH were achieved by pH meter. Thereafter, the extreme learning machine (ELM) was employed to calibrate model. In the calibration model, the optimal number of PCs and the optimal number of hidden-layer nodes of ELM network were determined by the cross-validation. Experimental results showed that the optimal ELM model was achieved with 10-40-1 topology construction as follows: Rp=0.961 8 and RMSEP=0.104 4 in the prediction set. The research achievement could provide technological basis for the on-line measurement of the process parameters in solid-state fermentation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 970 (2012)
Quantitative Analysis of Goose and Duck Mixed Down Using Visible/NIR Spectroscopy
XU Hui-rong, SONG Bao-guo, WAN Wang-jun, ZHOU Ying, and YING Yi-bin
Goose down and duck down have very similar appearance but the quality of goose down is better than that of duck down in general. There is a highest allowable limit as specified by the various national standards of feather and down for the percentage of duck feather or down mixed in goose feather or down. Traditional deGoose down and duck down have very similar appearance but the quality of goose down is better than that of duck down in general. There is a highest allowable limit as specified by the various national standards of feather and down for the percentage of duck feather or down mixed in goose feather or down. Traditional detection method, manual inspection with a high-scale microscope, is labor intensive and not suitable for large-volume samples analysis and on-site rapid testing. In the present paper, visible/near-infrared (NIR) spectroscopy combined with successive projection algorithm (SPA) for characteristic wavelengths selection was used to determinate the content of duck down mixed in goose down. In the range of 450~930 nm, the multiple linear regression (MLR) model established with the 8 characteristic wavelengths selected by SPA achieved good prediction, the correlation coefficient of 0.983, root mean square error of calibration (RMSEC) of 5.44%, and root mean square error of prediction (RMSEP) of 5.75%. Therefore, it is expected to be used for rapid detection of feather and down quality in future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 974 (2012)
Nondestructive Measurement of Cellular ATP Contents in Vegetables Using UV-Vis-NIR Spectroscopy
YE Xu-jun, Seiichi Oshita, Yoshio Makino, QIAN Qiong-qiu, and HE Yong
The cellular ATP content level in agricultural products directly reflects cell viability, therefore it can be potentially used as an indicator of freshness and quality of agricultural products during storage. Spectral data of sample spinach leaves were obtained using a UV-Vis-NIR spectrophotometer UV-3600. Protoplast sThe cellular ATP content level in agricultural products directly reflects cell viability, therefore it can be potentially used as an indicator of freshness and quality of agricultural products during storage. Spectral data of sample spinach leaves were obtained using a UV-Vis-NIR spectrophotometer UV-3600. Protoplast suspensions were prepared by following the conventional physical-chemical methods, and the ATP contents in protoplasts were determined by the firefly luciferase bioluminescence technology. Person’s correlation analysis was performed to identify the key wavelengths. Models were developed for estimating the ATP contents in spinach protoplasts based on the two identified key wavelengths, i.e. the ultraviolet 298 nm and the near-infrared 730 nm wavelengths. Results showed that both of the two key wavelengths (298 and 730 nm) have a considerable promise in estimating the ATP content in spinach protoplasts (R2=0.802 9 and 0.901 respectively). The spectroscopy based estimation of cellular ATP content in vegetables proposed in this study provides a new approach to the accurate, rapid, and non-destructive evaluation of the freshness of vegetables..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 978 (2012)
Simultaneous Determination of Instant Coffee, Plant Fat and Sugar Content in Liquid Coffee Beverage by Diffuse Reflectance Near-Infrared Spectroscopy
WANG Dong, MIN Shun-geng, DUAN Jia, XIONG Yan-mei, and LI Qian-qian
The diffuse reflectance near-infrared spectra of 20 liquid coffee beverage samples were collected by FT-NIR spectrometer combined with integral sphere in this thesis. The quantitative calibration models of instant coffee, plant fat and sugar were developed respectively. The result indicated that for the calibration modThe diffuse reflectance near-infrared spectra of 20 liquid coffee beverage samples were collected by FT-NIR spectrometer combined with integral sphere in this thesis. The quantitative calibration models of instant coffee, plant fat and sugar were developed respectively. The result indicated that for the calibration models of instant coffee, plant fat and sugar, the dimensions of the calibration models are 4, 5 and 4 respectively; the determination coefficients (R2) are 98.97%, 99.94% and 99.18% respectively; the root mean square errors of calibration (RMSEC) are 1.62, 0.42 and 1.58 respectively; the root mean square errors of cross validation (RMSECV) are 2.12, 0.72 and 2.01 respectively. The result of F-test showed that a very remarkable correlation exists between the estimated and specified values for each calibration model. This research indicated that NIR spectroscopy can be applied in the rapid, accurate and simultaneous determination of the three main ingredients in liquid coffee beverage. This research can provide some references for the quality control of liquid coffee beverage and the determination of the substance with chemical-fixation composition in liquid formula food..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 982 (2012)
High Temperature Raman Spectrum Study of LiTaO3
LIU Sheng-gang, LI Jun, and JING Qiu-min
The high temperature Raman spectrum of LiTaO3 was studied from 298 to 948 K by micro-confocal Raman technique and the mechanism of phase transition from ferroelectric phase to paraelectric phase was studied by analyzing the high wave number Raman peaks of LiTaO3. The experimental results show that all the Raman peaks eThe high temperature Raman spectrum of LiTaO3 was studied from 298 to 948 K by micro-confocal Raman technique and the mechanism of phase transition from ferroelectric phase to paraelectric phase was studied by analyzing the high wave number Raman peaks of LiTaO3. The experimental results show that all the Raman peaks except 466.7 cm-1 have a remarkable Raman shift to low frequency when increasing temperature. The full width at half maximum (FWHM) of all Raman peaks increases with increasing temperature, but the intensity weakens. At about 933 K, the phase transition is observed since the three Raman peaks disappear. And at about this temperature, the FWHM of 359.5, 385.0 and 466.7 cm-1 shows an obviously superlinear increasing. From the experimental results, we conclude that the phase transition is a mixed phase transition, and the phase transition is reversible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 985 (2012)
Identification of Ginseng and Its Counterfeit by Laser Raman Spectroscopy
WAN Qiu-e, LIU Han-ping, ZHANG He-ming, and LIU Song-hao
The objective of the present study is to identify Ginseng and its false sample ： Anthriscus sylvestris, Radix glehniae and balloonflower root by Laser Raman spectroscopy, second derivative Raman spectroscopy. The structural information of the samples indicated that Ginseng and its false samples contains a large amount The objective of the present study is to identify Ginseng and its false sample ： Anthriscus sylvestris, Radix glehniae and balloonflower root by Laser Raman spectroscopy, second derivative Raman spectroscopy. The structural information of the samples indicated that Ginseng and its false samples contains a large amount of carbohydrates, since some characteristic vibration peaks of the carbohydrates, such 1 640， 1 432， 1 130， 1 086， 942， 483 cm-1can be observed. The characteristic vibration peak of Radix glehniae which arouse at 2 206 cm-1 in the aman spectra, totally different from the other three kinds of traditional Chinese medicines. Anthriscus sylvestris appeare the characteristic vibration peak in 1 050 cm-1 and the corresponding 1 869 cm-1 because of the chain ester compounds. The characteristic vibration peak of balloonflower root, such as 1 227， 691， 600 cm-1 can be observed, significantly different from the other three herbs in the Raman spectra. Further more,the previous identification results can be verified again with second derivative Raman spectroscopy. This identification method is more fast, convenient, and keeping the integrity of the samples than the routine spectroscopic method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 989 (2012)
Study of the Raman-AFM System for Simultaneous Measurements of Raman Spectrum and Micro/Nano-Structures
SHI Bin, ZHANG Hai-jun, WU Lan, and ZHANG Dong-xian
This paper proposes a novel technique of Raman-atomic force microscopy (AFM) combining micro region Raman spectroscopy and AFM imaging. An in-situ probe unit which can simultaneously realize the detection of Raman spectrum and the measurement of AFM image was designed, and a related Raman-AFM system was constructed. UsThis paper proposes a novel technique of Raman-atomic force microscopy (AFM) combining micro region Raman spectroscopy and AFM imaging. An in-situ probe unit which can simultaneously realize the detection of Raman spectrum and the measurement of AFM image was designed, and a related Raman-AFM system was constructed. Using this system, some experiments were carried out to acquire micro region Raman spectra and AFM images of ZnO nano-particle and TiO2 film. The results show that the Raman spectra of both samples are in agreement with theoretical vaues, and the AFM images represent their micro/nano-structures quite well. These researches prove the feasibility of the Raman-AFM technique which has the potential of being widely applied in the fields of Raman spectroscopy and micro/nano-technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 993 (2012)
Influence of Cations on the Laser Raman Spectra of Silicate Glasses
XIONG Yi, ZHAO Hong-xia, and GAN Fu-xi
Na2O(K2O)—CaO(MgO)—SiO2, Na2O(K2O)—Al2O3—SiO2, Na2O(K2O)—B2O3—SiO2, Na2O(K2O)—PbO—SiO2 and PbO—BaO—SiO2 glass systems were investigated using laser Raman spectroscopic technique. The modification of short-range structure of glass caused by network modifier cations will influence Raman signature. Alkali and alkali-earthNa2O(K2O)—CaO(MgO)—SiO2, Na2O(K2O)—Al2O3—SiO2, Na2O(K2O)—B2O3—SiO2, Na2O(K2O)—PbO—SiO2 and PbO—BaO—SiO2 glass systems were investigated using laser Raman spectroscopic technique. The modification of short-range structure of glass caused by network modifier cations will influence Raman signature. Alkali and alkali-earth ions can weaken the bridging oxygen bond, thus lower the frequency of Si—Ob—Si anti-symmetric stretching vibration. When coordinated by oxygen ions, B3+ can form ［BO4］ tetrahedron and enter the silicon-oxygen network, but this effect had little impact on the frequency of Raman peaks located in the high-frequency region. Al3+ can also be coordinated by oxygen ions to form ［AlO4］ tetrahedron. ［AlO4］ will increase the disorder degree of network while entering network. Ba2+ can increase the density of electron cloud along the Si—Onb bond when it bonds with non-bridging oxygen, which will lead to a higher peak intensity of O—Si—O stretching vibration. The Raman peaks of alkli- and alkali-earth silicate glasses are mainly distributed in the region of 400~1 200 cm-1, while in the spectrum of Na2O(K2O)—PbO—SiO2 glass system a 131 cm-1 peak existed. The authors assigned it to the Pb—O symmetric stretching vibration. Some of the samples were produced in the laboratory according to the average compositions of ancient glasses, so this research is very significant to discriminating ancient silicate glasses of different systems by Laser Raman spectroscopic technique..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 997 (2012)
Confocal Raman Microspectroscopy Study on the Distribution of Cellulose and Lignin in Daphne odora Thunb.
ZHANG Zhi-heng, MA Jian-feng, and XU Feng
Confocal Raman microspectroscopy is well suited to investigating cellulose and lignin distribution in-situ in the native cell walls of woody tissue. In this study, transmission electron microscopy (TEM) was used to determine the ultrastructure of Daphne odora Thunb.. In the TEM images, cell wall of Daphne odora Thunb. Confocal Raman microspectroscopy is well suited to investigating cellulose and lignin distribution in-situ in the native cell walls of woody tissue. In this study, transmission electron microscopy (TEM) was used to determine the ultrastructure of Daphne odora Thunb.. In the TEM images, cell wall of Daphne odora Thunb. is typically divided into three layers: middle lamellar (ML), primary wall (P) and secondary wall (S1, S2 and S3). More detailed information about cellulose and lignin distribution in different cell wall layers was analyzed in situ by confocal Raman microspectroscopy. Raman spectra and images reveal that the distribution of cellulose and lignin in the cell wall layers is not uniform. Lignin concentration in different morphological areas follows the decreasing order: the cell corner (CC)> the middle lamellar (CML)> the secondary wall (S2). In contrast, cellulose distribution shows the opposite pattern-low concentration in CC and CML and high in S2 regions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1002 (2012)
Fluorescence Characteristics of Dissolved Organic Matter in the Sea Nearby Zhangzi Island
ZHOU Nan, ZHAO Wei-hong, and MIAO Hui
Fluorescence excitation-emission matrix spectroscopy (EEMs) was parsed, using parallel factor analysis (PARAFAC) to parse the model, to examine the fluorescent components and their distributing variations of dissolved organic matter (DOM) sampled from the nearby sea area of Zhangzi island. The identified components in Fluorescence excitation-emission matrix spectroscopy (EEMs) was parsed, using parallel factor analysis (PARAFAC) to parse the model, to examine the fluorescent components and their distributing variations of dissolved organic matter (DOM) sampled from the nearby sea area of Zhangzi island. The identified components in different seasons were almost similar, including humic-like components C1(265/440 nm), C2(410～450/520～550 nm) and protein-like component C3(230, 280/330 nm), and the good linearity proved that they had the same sources or some relationships. Furthermore, all of the 3 components in different water layers and different seasons showed higher fluorescence intensity around the Zhangzi island. The relationships of the 3 components with chlorophyll-a and salinity were discussed, and the results showed that DOM in the study area depended on phytoplankton and the input from human activities. The results demonstrate the capability of the combination of EEMs and PARAFAC for characterizing fluorescence of DOM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1007 (2012)
Identification of Spill Oil Species Based on Low Concentration Synchronous Fluorescence Spectra and RBF Neural Network
LIU Qian-qian, WANG Chun-yan, SHI Xiao-feng, LI Wen-dong, LUAN Xiao-ning, HOU Shi-lin, ZHANG Jin-liang, and ZHENG Rong-er
In this paper, a new method was developed to differentiate the spill oil samples. The synchronous fluorescence spectra in the lower nonlinear concentration range of 10-2~10-1 g·L-1 were collected to get training data base. Radial basis function artificial neural network (RBF-ANN) was used to identify the samples sIn this paper, a new method was developed to differentiate the spill oil samples. The synchronous fluorescence spectra in the lower nonlinear concentration range of 10-2~10-1 g·L-1 were collected to get training data base. Radial basis function artificial neural network (RBF-ANN) was used to identify the samples sets, along with principal component analysis (PCA) as the feature extraction method. The recognition rate of the closely-related oil source samples is 92%. All the results demonstrated that the proposed method could identify the crude oil samples effectively by just one synchronous spectrum of the spill oil sample. The method was supposed to be very suitable to the real-time spill oil identification, and can also be easily applied to the oil logging and the analysis of other multi-PAHs or multi-fluorescent mixtures..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1012 (2012)
Study on the Spectral Properties of Ca7(SiO4)2Cl6 Phosphor for White LED
LIU Chong, GUAN Li, ZHANG Hao, LI Pan-lai, GUO Qing-lin, YANG Zhi-ping, and FU Guang-sheng
A bluish green Ca7(SiO4)2Cl6∶Eu2+ phosphor used for UV excited white LED was synthesized by high temperature solid state method. The XRD patterns and luminescence properties were investigated. The results indicated that the sample was single Ca7(SiO4)2Cl6 phase; the emission spectrum included two emission peaks locatedA bluish green Ca7(SiO4)2Cl6∶Eu2+ phosphor used for UV excited white LED was synthesized by high temperature solid state method. The XRD patterns and luminescence properties were investigated. The results indicated that the sample was single Ca7(SiO4)2Cl6 phase; the emission spectrum included two emission peaks located at 418 and 502 nm, respectively. Monitoring for the two emission peaks, the excitation spectra were two broad band peaks centered at 290 and 360 nm respectively, which illustrated that Eu2+ ions located at two different crystal lattice sites. The influence of Eu2+ ions concentration on the luminescence intensity was studied and the optimal doping concentration was 0.75 mol%. The results showed that this phosphor was a better candidate bluish phosphor for UV based white LED..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1016 (2012)
Preparation, Characterization and Photocatalytic Activities of Polyoxometalates Immobilized on Mesoporous Moleculer Sieve
LIU Xia, LI Yan-zhou, and FENG Chang-gen
Heterogeneous photocatalysts consisting of phosphotungstic acid or silicotungstic acid immolilized on mesoporous molecular sieve MCM-41 were prepared and characterized by FTIR, X-ray diffraction, nitrogen adsorption and high resolution transmission electron microscope (HRTEM). The photocatalytic activities of the prepaHeterogeneous photocatalysts consisting of phosphotungstic acid or silicotungstic acid immolilized on mesoporous molecular sieve MCM-41 were prepared and characterized by FTIR, X-ray diffraction, nitrogen adsorption and high resolution transmission electron microscope (HRTEM). The photocatalytic activities of the prepared H3PW12O40/MCM-41 or H4SiW12O40/MCM-41 were examined by photodegradation of pesticide paraquat. Results show that the prepared composites have large specific surface area and uniform mesopores, the Keggin structure of two parent heteropoly acids was retained after loading on MCM-41. Both of the prepared photocatalysts exhibit high activityies under irradiation of 365 nm monochromatic Light. For 50 mL paraquat (10 mg·L-1), conversions of paraquat using 15 mg H3PW12O40/MCM-41 or H4SiW12O40/MCM-41 as catalysts after 14 hours’ irradiation are 92.0% and 87.6% respectively. The photocatalytic reactions are in accordance with the first order kinetics equation, and the half lives of the reactions are 3.6 h and 4.7 h respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1020 (2012)
Low Level Laser Irradiation in the Visible Spectra Induces HeLa Cells Proliferation
YANG Hong-qin, WANG Yu-hua, CHEN Jiang-xu, ZHENG Li-qin, and XIE Shu-sen
The aim of this in vitro study was to evaluate the effects of low level laser irradiation on the proliferation of HeLa cells using 405 nm diode laser, 514 nm argon laser, 633 nm He-Ne laser, or 785 nm diode laser. The cells were seeded on 96-well microplates for 24 h in 5% fetal bovine serum containing medium, then irrThe aim of this in vitro study was to evaluate the effects of low level laser irradiation on the proliferation of HeLa cells using 405 nm diode laser, 514 nm argon laser, 633 nm He-Ne laser, or 785 nm diode laser. The cells were seeded on 96-well microplates for 24 h in 5% fetal bovine serum containing medium, then irradiated with the laser at dose of 100 and 1 000 J·m-2, respectively. At the time point of 24, 48, 72 h after irradiation, cell viability was assessed by MTT assay. The results show that 405, 633 and 785 nm laser irradiation induces wavelength-dependent and time-dependent proliferation. 633 nm laser irradiation results in a stimulatory proliferation effect that is most significant, whereas 514 nm laser irradiation produces little increase in cell proliferation. Low level laser irradiation increases cell proliferation in a dose-dependent manner. 1 000 J·m-2 laser irradiation is more effective in increasing cell proliferation than 100 J·m-2 laser irradiation using 405 nm diode laser, 633 nm He-Ne laser, or 785 nm diode laser, but not as effective as using 514 nm argon laser..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1024 (2012)
Research on the Method of Transient Spectrum Detection Based on Array CCD
ZHU Bing-li, BAI Yong-lin, WANG Bo, LIU Bai-yu, OUYANG Xian, YANG Wen-zheng, BAI Xiao-hong, QIN Jun-jun, ZHAO Jun-ping, GOU Yong-sheng, and LU Kai
Based on the characteristic of high speed line scanning for CCD in transient spectrum detection, a method of transient spectrum detection with array CCD is presented. The high speed line scanning with array CCD was realized by changing the mode of charge transfer. In order to explore the feasibility of this method, a fBased on the characteristic of high speed line scanning for CCD in transient spectrum detection, a method of transient spectrum detection with array CCD is presented. The high speed line scanning with array CCD was realized by changing the mode of charge transfer. In order to explore the feasibility of this method, a fast detection system of single point based on linear CCD was designed and fabricated. Seven different LED pulses were measured when the system worked at fast detection mode of single point and normal mode respectively. The results demonstrate that the method of fast detection of single point based on linear CCD is feasible, and the rate of single point detection reaches up to 20 MHz. Thus, in theory, it was proved that transient spectrum detection with array CCD by changing the mode of charge transfer is also feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1028 (2012)
Temporal Mixture Analysis Application in Monitoring the Antarctic Sea Ice Concentration Variability
BI Hai-bo, and LI Shuang-shuang
Temporal mixture analysis (TMA) is deduced from spectral mixture analysis (SMA). They are algebraically identical except for that TMA is applied to temporal spectra and thus can extract the temporal characteristics of features. The ice concentration is diverse across the Antarctic sea through different periods, and TMATemporal mixture analysis (TMA) is deduced from spectral mixture analysis (SMA). They are algebraically identical except for that TMA is applied to temporal spectra and thus can extract the temporal characteristics of features. The ice concentration is diverse across the Antarctic sea through different periods, and TMA has a great potential to obtain this variability as an environmental normal. In the present study, sea ice concentration data remotely sensed by AMSR-E from 2003 to 2010 were used and seven typical endmembers were captured, standing for temporally different sea ice classification. TMA can also be utilized in change analysis of Antarctic sea ice concentration for its capability to record the spatial distribution of temporal characteristics, allowing further study of regional or global climatic variations. In short, TMA supplies a new method for researchers to investigate the spatial and temporal variability of polar sea ice..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1032 (2012)
Application of Direct Orthogonal Signal Correction Algorithm in Multi-Component Alkane Quantitative Analysis
LI Yu-jun, TANG Xiao-jun, and LIU Jun-hua
According to the baseline departure of multi-component alkane gas mixture spectra, direct orthogonal signal correction (DOSC) algorithm was proposed to pretreat the infrared spectra data. Fourier transform infrared (FTIR) spectrometer was used to sample 936 spectra data of seven components gas mixture, including methanAccording to the baseline departure of multi-component alkane gas mixture spectra, direct orthogonal signal correction (DOSC) algorithm was proposed to pretreat the infrared spectra data. Fourier transform infrared (FTIR) spectrometer was used to sample 936 spectra data of seven components gas mixture, including methane, ethane, propane, iso-butane, n-butane, iso-pentane and n-pentane gases. The concentration of each component ranges from 0.01% to 0.1%, 0.01% to 0.1%, 0.01% to 0.15%, 0.0% to 0.1%, 0.0% to 0.1%, 0.0% to 0.05%, and 0.0% to 0.05%, respectively. For analyzing intuitively, partial least square regression (PLSR) was introduced to build the component gas quantitative analysis model. In experiment, DOSC method was compared with first derivative algorithm (FDA) and second derivative algorithm (SDA). In order to get the optimal model, ergodic optimization method was used to select the optimal parameters of the model, i.e. the step of the derivative algorithm, the number of the primary component of the PLSR and the number of orthogonal components of the DOSC algorithm. The experiment results show that DOSC algorithm has the better effect in the field of infrared spectra data pretreating. The average mean relative error (MRE) of the component gas analysis models is 16.58%, which declined by 66.80% from the average MRE before data pretreating 49.93%. Compared with DA, the average MRE declined by 51.51% from 34.19% after pretreated by FDA, and declined by 56.30% from 37.94% after pretreated by SDA. So DOSC method is feasible to pretreat the IR spectra data, and has definite practical and investigation value..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1038 (2012)
Extracting THz Absorption Coefficient Spectrum Based on Accurate Determination of Sample Thickness
LI Zhi, ZHANG Zhao-hui, ZHAO Xiao-yan, SU Hai-xia, and YAN Fang
Extracting absorption spectrum in THz band is one of the important aspects in THz applications. Sample’s absorption coefficient has a complex nonlinear relationship with its thickness. However, as it is not convenient to measure the thickness directly, absorption spectrum is usually determined incorrectly. Based on theExtracting absorption spectrum in THz band is one of the important aspects in THz applications. Sample’s absorption coefficient has a complex nonlinear relationship with its thickness. However, as it is not convenient to measure the thickness directly, absorption spectrum is usually determined incorrectly. Based on the method proposed by Duvillaret which was used to precisely determine the thickness of LiNbO3, the approach to measuring the absorption coefficient spectra of glutamine and histidine in frequency range from 0.3 to 2.6 THz(1 THz=1012 Hz) was improved in this paper. In order to validate the correctness of this absorption spectrum, we designed a series of experiments to compare the linearity of absorption coefficient belonging to one kind amino acid in different concentrations. The results indicate that as agreed by Lambert-Beer’s Law, absorption coefficient spectrum of amino acid from the improved algorithm performs better linearity with its concentration than that from the common algorithm, which can be the basis of quantitative analysis in further researches..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1043 (2012)
Synthesis and Optical Properties of Nd(Ⅲ) Perfluoro-Carboxylate Complexes with 2,2’-Bipyridine
SHE Jiang-bo, LI Dong-dong, WANG Peng-fei, ZHU Yong-gang, WEI Wei, and PENG Bo
A series of neodymium complexes, Nd(CF3COO)3·Dipy, Nd(C2F5COO)3·Dipy and Nd(C3F7COO)3·Dipy were synthesized and characterized by FTIR spectra, elemental analysis, thermogravimetric analysis, UV-Vis-NIR absorption spectra and PL spectra. The decomposition temperature was found to be more than 260 ℃ and maA series of neodymium complexes, Nd(CF3COO)3·Dipy, Nd(C2F5COO)3·Dipy and Nd(C3F7COO)3·Dipy were synthesized and characterized by FTIR spectra, elemental analysis, thermogravimetric analysis, UV-Vis-NIR absorption spectra and PL spectra. The decomposition temperature was found to be more than 260 ℃ and maximum weight losses rates above 340 ℃ which indicate that they have good thermal stability. The low vibrational energy C—F bonds were used to replace the C—H bonds in organic group for improving the optical properties of materials. The length of carbon chain and the coordination structure of Nd(Ⅲ) affect the absorption transition strength. According to the UV-Vis-NIR absorption spectra, the Judd-Ofelt parameters were calculated and the radiative properties were also presented. The stimulated emission cross-sections of the Nd(CF3COO)3·Dipy, Nd(C2F5COO)3·Dipy and Nd(C3F7COO)3·Dipy were 3.63×10-20, 2.36×10-20 and 1.49×10-20 cm2 respectively, which were as good as some reported inorganic materials. These complexes will be a series of promising materials for liquid laser application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1047 (2012)
Spectroscopic and Structural Characteristics of the Main Components of Theabrownin in Pu-erh Tea
TAN Chao, PENG Chun-xiu, GAO Bin, and GONG Jia-shun
In the present study, we fractionated the main components of TB in Pu-erh tea by dialysis and investigated their compositions, structures and properties. TB in the Pu-erh tea was fractionated by dialyses using films with different pore sizes. The highest TB concentration was obtained in the fraction with molecular weigIn the present study, we fractionated the main components of TB in Pu-erh tea by dialysis and investigated their compositions, structures and properties. TB in the Pu-erh tea was fractionated by dialyses using films with different pore sizes. The highest TB concentration was obtained in the fraction with molecular weight species >25 000 Da. The carboxyl and hydroxyl concentrations also increased in fractions where the molecular weight size selection was highest (i.e., >25 000 Da). AFM images revealed that TB particles with different molecular weights had different morphologies and the TB particles appeared as scattered islands or aggregates. CP-MAS NMR experiments revealed that the TB fraction with molecular weight species between 3 500 and 25 000 Da in size was characterized by a polymeric material of polyphenols. This polymeric substance contained primarily multiple benzene rings, polysaccharides, protein residue groups and various other functional groups. After acidic hydrolysis, this fraction formed a black precipitate. CP-MAS NMR found that the precipitate was a polymeric material with multiple benzene rings. CP-GC/MS identified 16 candidate compounds from the pyrolysis products of the black precipitate obtained from the main fraction with molecular weight species between 3 500 and 25 000 Da..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1051 (2012)
Surfactant-Assisted Solid-Phase Synthesis and Spectral Characterization of Silver Iodide Nanowire Bundles
LIU Ying, FENG Jin-chao, and LI Jin-shu
In the present paper, AgNO3 and KI were used as raw materials synthesize silver iodide nanowire bundles in the condition of nonionic surfactant polyethylene glycol (PEG-400) at room temperature. XRD, TEM and SEM techniques were used to characterize the silver iodide structure and morphology. The results indicated that In the present paper, AgNO3 and KI were used as raw materials synthesize silver iodide nanowire bundles in the condition of nonionic surfactant polyethylene glycol (PEG-400) at room temperature. XRD, TEM and SEM techniques were used to characterize the silver iodide structure and morphology. The results indicated that the product was one-dimensional silver iodide nanowire bundles with diameters of 80~100 nm and lengths of 20 μm, and the length-diameter ratio was greater than 200. In the forming process of silver iodide nanowire bundles, PEG-400 surfactant was used as soft template agent, which induced the product nanocrystalline along a particular direction and directional orderly growth so as to generate nanowire bundles. This method with a simple operation and low cost eliminated the influence of water on the reaction process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1057 (2012)
Spectral Properties of Interaction between Caffeic Acid and Milk Protein and The Change in Antioxidant Capacity
YU Dan-dan, ZHANG Hao, DING Qing-bo, GUO Hui-yuan, WU Jian-ping, ZHANG Lu-da, and REN Fa-zheng
The interaction between caffeic acid and milk protein (α-casein, β-casein, κ-casein, α-lactalbumin, β-lactoglobulin) were studied in this work. The binding constant KA, binding force, binding distance r0 and transfer efficiency E were evaluated by UV-absorption and fluorescence spectroscopy. The antioxidant capacity ofThe interaction between caffeic acid and milk protein (α-casein, β-casein, κ-casein, α-lactalbumin, β-lactoglobulin) were studied in this work. The binding constant KA, binding force, binding distance r0 and transfer efficiency E were evaluated by UV-absorption and fluorescence spectroscopy. The antioxidant capacity of the combination was determined using both 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay. The results showed that the interaction between milk protein and caffeic acid resulted in the endogenous fluorescence quenching of milk protein, which belongs to a static quenching mechanism. The negative sign of free energy meant that the interaction process was spontaneous. The strength between caffeic acid and α-casein was electrostatic attraction (ΔH<0, ΔS>0), and that between β-casein and α-Lactalbumin was hydrogen bonding (ΔH<0, ΔS<0). In addition, the strength of caffeic acid interacting with κ-casein and β-lactoglobulin was hydrophobic interaction (ΔH>0, ΔS>0). The binding distance (r0<7 nm) proved that caffeic acid lead to a static quenching mechanism of milk protein. The antioxidant capacity of caffeic acid was inhibited by milk protein to different degrees..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1061 (2012)
Study of pH Measuring Based on i-Motif DNA Conformation Switch and UV-Vis Absorption Spectroscopy of Gold Nanoparticles
ZHONG Jian-hai, GUO Liang-qia, WU Jin-mei, CHEN Jin-feng, and CHEN Zhang-jie
A fast, sensitive, colorimetric method for the detection of pH based on the differentiate effect of gold nanoparticles to the configuration of DNA was developed in this study. The UV-Vis absorption spectroscopy of the i-motif DNA-Au NPs system has been investigated, and the effect of the concentration of salt and i-motA fast, sensitive, colorimetric method for the detection of pH based on the differentiate effect of gold nanoparticles to the configuration of DNA was developed in this study. The UV-Vis absorption spectroscopy of the i-motif DNA-Au NPs system has been investigated, and the effect of the concentration of salt and i-motif DNA, reaction time and DNA sequence on the pH response of the system have been also optimized. Under the optimum conditions, the UV-Vis absorption spectroscopy of the Au NPs is changed regularly with pH in the range of 5.3～7.0, the absorbance at 520 nm is increased gradually while at 700 nm decreased. Correspondingly, the color of the Au NPs is varied from violet to red. The pH sensor is no need to modification, low cost, fast and can be carried out by naked eyes. It is promising to use in monitoring some life process which associated with pH variation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1068 (2012)
On Using Tunable Diode Laser Absorption Spectroscopy to Determine Gas Fluxes over Cropland
TIAN Yong-zhi, LIU Jian-guo, ZHANG Yu-jun, LU Yi-huai, and HE Ying
Tunable diode laser absorption spectroscopy (TDLAS) is a compact, automated, high precision technique and fit for in-situ or field measurements. Two spectroscopy measurement systems, TDLAS and NDIR (non-dispersive infrared spectroscopy), were used to monitor trace gas emission over cropland at Fengqiu Agricultural EcolTunable diode laser absorption spectroscopy (TDLAS) is a compact, automated, high precision technique and fit for in-situ or field measurements. Two spectroscopy measurement systems, TDLAS and NDIR (non-dispersive infrared spectroscopy), were used to monitor trace gas emission over cropland at Fengqiu Agricultural Ecology Experimental Station for one month. The fluxes of carbon dioxide were estimated by flux-gradient and eddy covariance method, respectively. A footprint model was developed during experiment. Based on this model, the source areas of TDLAS and NDIR were investigated. The effects of different factors on the flux measurement were also analyzed. The authors concluded that the source areas for the two techniques are discrepant in most of the cases. The source areas increase with path length and detecting height. This result will help the installation of instruments..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1072 (2012)
The Concentration Resolution of Complex Liquid Spectrometry Analysis and the Effect of Concentration Distribution
LI Gang, ZHAO Zhe, WANG Hui-quan, LIN Ling, ZHANG Bao-ju, and WU Xiao-rong
In order to ensure the feasibility of complex liquid spectroscopy analysis， to analyze the accuracy gain of modeling by multi-wavelength, and to determine the appropriate distribution of concentration to obtain the high quality and universal quantitative analysis model, the precision of the detection of composition conIn order to ensure the feasibility of complex liquid spectroscopy analysis， to analyze the accuracy gain of modeling by multi-wavelength, and to determine the appropriate distribution of concentration to obtain the high quality and universal quantitative analysis model, the precision of the detection of composition concentration by spectral analysis is illustrated through a error analysis which takes into account the following three contributions: spectral instrument noise， multi-wavelength modeling and the distribution of composition concentration. By concentration resolution analysis, the concentration resolution can be achieved when the spectrometer noise is available, but also the theoretical basis is provided to select a suitable spectrometer to meet the resolution requirement of quantitative analysis. Over-sampling technique indicates that the precision improvement by modeling with multi-wavelength can obtain higher concentration detection sensitivity. The sparse-dense-ratio and Euclidean distance of both measured and non-measured components provide the theoretic guidance for choosing the suitable concentration distribution which improves the model’s quality and reduces the prediction error of the sample set..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1077 (2012)
Spectral Features Analysis of Sea Ice in the Arctic Ocean
KE Chang-qing, XIE Hong-jie, LEI Rui-bo, LI Qun, and SUN Bo
Sea ice in the Arctic Ocean plays an important role in the global climate change, and its quick change and impact are the scientists’ focus all over the world. The spectra of different kinds of sea ice were measured with portable ASD FieldSpec 3 spectrometer during the long-term ice station of the 4th Chinese national Sea ice in the Arctic Ocean plays an important role in the global climate change, and its quick change and impact are the scientists’ focus all over the world. The spectra of different kinds of sea ice were measured with portable ASD FieldSpec 3 spectrometer during the long-term ice station of the 4th Chinese national Arctic Expedition in 2010, and the spectral features were analyzed systematically. The results indicated that the reflectance of sea ice covered by snow is the highest one, naked sea ice the second, and melted sea ice the lowest. Peak and valley characteristics of spectrum curves of sea ice covered by thick snow, thin snow, wet snow and snow crystal are very significant, and the reflectance basically decreases with the wavelength increasing. The rules of reflectance change with wavelength of natural sea ice, white ice and blue ice are basically same, the reflectance of them is medium, and that of grey ice is far lower than natural sea ice, white ice and blue ice. It is very significant for scientific research to analyze the spectral features of sea ice in the Arctic Ocean and to implement the quantitative remote sensing of sea ice, and to further analyze its response to the global warming..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1081 (2012)
The Study of Maximum Entropy Method Used in Wind Profiler
HU Ming-bao, ZHENG Guo-guang, and ZHANG Pei-chang
In order to know the feasibility that the modern spectrum analysis ways are applied in wind profiler, the fast Fourier transform (FFT) and maximum entropy method (MEM) are contrasted by using simulation data and radar measurement data respectively. The result shows：(1）When the radar echo is strong, the effect of two meIn order to know the feasibility that the modern spectrum analysis ways are applied in wind profiler, the fast Fourier transform (FFT) and maximum entropy method (MEM) are contrasted by using simulation data and radar measurement data respectively. The result shows：(1）When the radar echo is strong, the effect of two methods are equivalent. But when the echo is weak, the MEM spectra are better than others. The MEM can powerfully remove the ground clutter contaminant. (2）The MEM spectra are smooth, so it can be used to reduce white noise influence also. (3）The iterative steps in MEM have some influence on the spectrum. The step calculated by final prediction error（FPE）rule is less. Using 15 steps in MEM can get a better result. The wind profiler radar echo is weak usually, so the conclusions of this paper can help improve the effect of spectrum analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1085 (2012)
Biosynthesis of CdS Quantum Dots in Saccharomyces Cerevisiae and Spectroscopic Characterization
HUANG Huai-qing, HE Ming-xin, WANG Wen-xing, LIU Jin-ling, MI Cong-cong, and XU Shu-kun
In the present work, CdS quantum dots (QDs) were successfully biosynthesized at room temperature by using saccharomyces cerevisiae yeast as a carrier. Fluorescence emission spectra, ultraviolet-visible (UV/Vis) absorption spectra, and inverted fluorescence microscope images confirmed that saccharomyces cerevisiae can bIn the present work, CdS quantum dots (QDs) were successfully biosynthesized at room temperature by using saccharomyces cerevisiae yeast as a carrier. Fluorescence emission spectra, ultraviolet-visible (UV/Vis) absorption spectra, and inverted fluorescence microscope images confirmed that saccharomyces cerevisiae can be used to biosynthesize CdS QDs. The as-prepared CdS QDs show the fluorescence emission peak at 443 nm and emit blue-green fluorescence under UV light (with excitation at 365 nm). Transmission electron microscopy (TEM) was applied to characterize the as-prepared CdS QDs and the TEM results showed that the as-prepared CdS QDs had the structure of hexagonal wurtzite. Fluorescence emission spectrum and UV/Vis absorption spectrum were used as the performance indicatiors to study the effects of saccharomyces cerevisiae yeast incubation times, reactant Cd2+ concentrations and reaction times on CdS QDs synthesis. Saccharomyces cerevisiae yeast grown in early stable phase can get the highest fluorescence intensity of CdS QDs when they were co-cultured with 0.5 mmol·L-1 of Cd2+ with 24 h incubation time. Furthermore, much more CdS QDs can be obtained by changing the culture medium during the synthesis process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1090 (2012)
Comparative Study on Thin Films of Cadmium Sulfide Prepared by Chemical Bath Deposition and Radio Frequency Magnetron Sputtering
WANG Sheng-li, WANG Xue-jin, WANG Wen-zhong, LIANG Chun-jun, WANG Zhi, and QI Zheng
Thin films of cadmium sulfide (CdS) were prepared with ammonium chloride, cadmium chloride, potassium hydroxide and thiourea by chemical bath deposition (CBD). For comparison, CdS films were also deposited by radio frequency (RF) magnetron sputtering, using CdS and argon as a target and reactive gas, respectively. The Thin films of cadmium sulfide (CdS) were prepared with ammonium chloride, cadmium chloride, potassium hydroxide and thiourea by chemical bath deposition (CBD). For comparison, CdS films were also deposited by radio frequency (RF) magnetron sputtering, using CdS and argon as a target and reactive gas, respectively. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet-visible spectroscopy. The results show that the CdS films prepared by the above two methods have (002) orientation, the CdS films deposited by RF magnetron sputtering are more compact and much smoother than those prepared by CBD, and have lager crystalline size of about 20~30 nm. The CdS films prepared by CBD have smaller crystalline size and more defects. The properties of CdS thin films prepared by RF magnetron sputtering are totally superior to those of CdS films by CBD, but the optical transmittance of CdS thin films at short wavelength is an exception. The energy gap of CdS films prepared by the two methods are all in the range of 2.3~2.5 eV..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1094 (2012)
Research on Partial Least Squares for Determination of Impurities in the Presence of High Concentration of Matrix by ICP-AES
WANG Yan-peng, GONG Qi, YU Sheng-rong, and LIU You-yan
A method for detecting trace impurities in high concentration matrix by ICP-AES based on partial least squares (PLS) was established. The research showed that PLS could effectively correct the interference caused by high level of matrix concentration error and could withstand higher concentrations of matrix than multicA method for detecting trace impurities in high concentration matrix by ICP-AES based on partial least squares (PLS) was established. The research showed that PLS could effectively correct the interference caused by high level of matrix concentration error and could withstand higher concentrations of matrix than multicomponent spectral fitting (MSF). When the mass ratios of matrix to impurities were from 1 000∶1 to 20 000∶1, the recoveries of standard addition were between 95% and 105% by PLS. For the system in which interference effect has nonlinear correlation with the matrix concentrations, the prediction accuracy of normal PLS method was poor, but it can be improved greatly by using LIN-PPLS, which was based on matrix transformation of sample concentration. The contents of Co， Pb and Ga in stream sediment (GBW07312) were detected by MSF, PLS and LIN-PPLS respectively. The results showed that the prediction accuracy of LIN-PPLS was better than PLS, and the prediction accuracy of PLS was better than MSF..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1098 (2012)
Determination of Microelements from Different Types of Grass in the Habitat of Przewalski’s Gazelle by Sealed Microwave Digestion ICP-AES
ZHOU Li-ye, XIN Guo-sheng, and PU Xiu-ying
For the mixture forge from different types of grassland, trace elements including copper, manganese, iron, zinc and molybdenum were separately determined by ICP-AES using high pressure system-sealed microwave digestion in the habitat of the Przewalski’s gazelle in Qinghai Hudong in summer (mid-June), autumn (mid-SeptemFor the mixture forge from different types of grassland, trace elements including copper, manganese, iron, zinc and molybdenum were separately determined by ICP-AES using high pressure system-sealed microwave digestion in the habitat of the Przewalski’s gazelle in Qinghai Hudong in summer (mid-June), autumn (mid-September) and winter (mid-December). The samples of mixture forage were digested with HNO3-H2O2 acids system. The detection limits of the method for the elements varied from 0.002 to 0.008 μg·g-1, with relative standard deviations between 0.13% and 4.29%, and the spike recovery ratios for them were in the range from 94.0% to 101.30%. This method was simple, sensitive and precise compared with conventional method, which will provide scientific basis for the research on gazelles habitat condition ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1103 (2012)
Determination of Trace Amounts of Mercury in Sediments by Sequential Injection Cold Vapor Atomic Fluorescence Spectrometry Coupled with
WANG Bin, ZHENG Cheng-bin, WANG Jun-wei, FENG Li, LI Shao-bo, DAN De-zhong, and LENG Geng
A novel method for the determination of trace amounts of mercury in sediments by sequential injection cold vapor atomic fluorescence spectrometry coupled with microwave assisted digestion was developed in this paper. Satisfactory results were found when the digestion was carried out at 140 ℃ for 5 min by using 10%HCl-5A novel method for the determination of trace amounts of mercury in sediments by sequential injection cold vapor atomic fluorescence spectrometry coupled with microwave assisted digestion was developed in this paper. Satisfactory results were found when the digestion was carried out at 140 ℃ for 5 min by using 10%HCl-50%HNO3-40%H2O or 30%HCl-20%HNO3-50%H2O media. The linear range was 0.02～30 ng·mL-1 with detection limit of 0.5 ng·g-1. Relative standard deviation for the complete procedure of the analysis of 10 digested sediment samples was 3.7%. Recoveries of the spiked samples were between (91.2±4.3)% and (96.5±4.6)%. The analytical results for three certified reference materials GSD-2, GSD-9 and GSD-10 were consistent with the certified values. The method has been successfully applied to six natural sediment samples. The results indicated that the method was rapid, highly sensitive and precision, and suitable for the determination of trace amounts of mercury in sediment samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1106 (2012)
Analysis of the Process of Chinese Purple Pigment Synthesis Using X-Ray Diffraction and Thermal Analysis Methods
CHEN Xi, QIN Ying, and LI Xiao-li
In the present article, according to the molecule formula of the Chinese purple and the result of most samples analysed in archaeology (PbO was contained more or less), the raw material of Chinese purple was prepared with the natural mineral resources, then the preparation was analyzed by thermogravimetry-differential In the present article, according to the molecule formula of the Chinese purple and the result of most samples analysed in archaeology (PbO was contained more or less), the raw material of Chinese purple was prepared with the natural mineral resources, then the preparation was analyzed by thermogravimetry-differential thermal analysis (TG-DTA), X-ray diffraction and thermal analysis methods for discussing which materials and what condition were used to produce Chinese purple in ancient China, in an attempt to explore the reason why the Chinese purple was invented in ancient China. The result showed that the use of witherite makes the synthetic condition facile, implying that the emergence of Chinese purple in ancient China is concerned with the use of this unique mineral containing barium..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1111 (2012)
TG-FTIR and XRD Spectroscopic Analysis for the Preparation of Nitrogen-Doped Carbon Supported Cobalt Electrocatalysts
YANG Wei, CHEN Sheng-zhou, ZOU Han-bo, and LIN Wei-ming
Nitrogen-doped carbon supported cobalt electrocatalysts for the reduction of oxygen were prepared from the high nitrogen content prepolymer of melamine formaldehyde resin and cobalt acetate. The preparation and structure of the electrocatalysts were investigated by TG-FTIR and XRD spectroscopic analysis methods. The elNitrogen-doped carbon supported cobalt electrocatalysts for the reduction of oxygen were prepared from the high nitrogen content prepolymer of melamine formaldehyde resin and cobalt acetate. The preparation and structure of the electrocatalysts were investigated by TG-FTIR and XRD spectroscopic analysis methods. The electrochemical reduction of oxygen was studied at the nitrogen-doped carbon supported cobalt by using the rotating disk electrode method. The results indicated that the catalyst structure changed with the carbonization temperature under the protection of the inert gases. Some organic groups were decomposed into CO, CO2, HCHO, NH3 and NO2, which were taken away by the protecting gas. The electrocatalysts exhibited face-centered cubic structure. The RDE results showed that good electrocatalytic activity for oxygen reduction at these electrocatalysts was found under the experimental condition. The onset potential for oxygen reduction (Eonset) was 0.5 V (vs. SCE). The catalyst prepared under 700 ℃ was found to have the highest activity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1114 (2012)
Spectroscopic Analysis of the Crystallization Mechanism of Synthesized Zeolite with XRD and FTIR Approaches
FAN Chun-hui, MA Hong-rui, and HUA Li
Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used Zeolites were synthesized from fly ash using modified one-stage method. The changes in cation exchange capacity (CEC) and chemical elements of zeolite were investigated during the synthesis process to reveal the materials and elements transformation in solid-liquid system. The approaches of XRD, SEM and FTIR were used to indicate the crystallization characteristics and mechanism. The zeolite NaP1 was synthesized, and the CEC value reached to the maximum of 135 mmol/100g at 24 h. After the hydrothermal reaction for 12 h, the characteristic peak and metastable crystalline structure of zeolite NaP1 appeared, then the hydroxy sodalite products formed at 48 h. The crystallization process was the result of materials transformation: the elements of fly ash released into the liquid system for the melting effect of alkali solution, and the solid system played the role of skeleton in crystallization process, being the “source” and the “sink” of the reaction, respectively, and the achievements presented the crystallization mechanism of liquid-phase and solid-phase transformation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1118 (2012)
Application of Internal Standard to Analysis of the Metal Ni Element in Soils by X-Ray Fluorescence Spectroscopy
ZHANG Wei, ZHANG Yu-jun, CHEN Dong, LIU Jing, WANG Chun-long, ZHANG Rong, ZHAO Nan-jing, and LIU Wen-qing
We quantitatively analyzed the content of the element Ni in the national standard soil samples by the method of X-ray fluorescence spectroscopy through using EDXRF metal experimental platform in ambient environment of the laboratory. Studying the characteristics of X-ray fluorescence of element Ni in the experiment，theWe quantitatively analyzed the content of the element Ni in the national standard soil samples by the method of X-ray fluorescence spectroscopy through using EDXRF metal experimental platform in ambient environment of the laboratory. Studying the characteristics of X-ray fluorescence of element Ni in the experiment，the calibration curve of element Ni was measured by using the adding internal standard method and the method of how to select the internal standard element was analysed according to the experimental results. The experimental results demonstrate that the matrix suitable element can be selected as the internal standard element to analyse the soil samples; using Pb Lα line, Cu, Fe and Kα lines as internal standard lines, the relative deviation of element from the standard value is 6.24%, 5.24% and 5.22%, which indicates that selecting the appropriate characteristic line of the matrix major element as the internal standard line can effectively improve measurement accuracy of the results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1123 (2012)
Wavelength Calibration Research on the Automatic Grating Monochromator for Orthogonal Czerny-Turner Structure
KOU Jie-ting, Bayanheshig, TANG Yu-guo, QI Xiang-dong, and YU Hong-zhu
The wavelength calibration research on the automatic grating monochromator for orthogonal Czerny-turner structure was investigated. Combined with the structure parameters and characteristic of this monochromator, the sinusoid that accords with the grating equation was proposed as the function of the wavelength calibratThe wavelength calibration research on the automatic grating monochromator for orthogonal Czerny-turner structure was investigated. Combined with the structure parameters and characteristic of this monochromator, the sinusoid that accords with the grating equation was proposed as the function of the wavelength calibration. Based on the principle of the least square method, the formula of the fitting residual error of the wavelength calibration was given. Using the Nelder-Mead simplex method, the undetermined coefficient of the fitting residual error was solved, which founded the precise formula between the wavelength and the grating turning angle. The accuracy of the method was verified through the experiment. The calibrated wavelength precision of the monochromator is less than 0.1 nm, which satisfies the application requirement. Applied in the wavelength calibration of the automatic grating monochromator with orthogonal Czerny-Turner structure, this method is simple to apply and easy for implementation. Using this method, the wavelength calibration can be realized quickly and real-timely, but it is only needed to modify the control program of the stepping motor slightly, which shows a better practicability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1127 (2012)
A Technology of Real-Time Image Compression for Convex Grating Imaging Spectrometer
LIU Yang-chuan, Bayanheshig, CUI Ji-cheng, and TANG Yu-guo
The huge amount of convex grating imaging spectrometer image data brings much pressure to data transmission and storage, so the image must be compressed in real time. Firstly, the image characteristics were analyzed according to the imaging principle, and the compression approach to removing spatial correlation and speThe huge amount of convex grating imaging spectrometer image data brings much pressure to data transmission and storage, so the image must be compressed in real time. Firstly, the image characteristics were analyzed according to the imaging principle, and the compression approach to removing spatial correlation and spectral correlation was achieved; Secondly, the compression algorithms were analyzed and the 3-D compression scheme of one-order linear compression in spectral dimension and JPEG2000 compression in spatial dimension was proposed. Finally, a real-time compression system based on FPGA and ADV212 was designed, in which FPGA was used for logic control and implementation of prediction algorithm, and ADV212 was used for JPEG2000 compression. The analysis result shows that the system has the ability of lossless and lossy compression, enabling real-time image compression..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1132 (2012)
Modeling and Correction of the Effect of Detector Lateral Fringe Error in the Large Aperture Static Imaging Spectrometer
XIANGLI Bin, L Qun-bo, YUAN Yan, HUANG Min, ZHOU Jin-song, and ZHANG Gui-feng
When the large aperture static imaging spectrometry (LASIS) was used in spaceborne remote sensing, the spectrum could not be well recovered from the interferogram with detector lateral fringe error. In order to obtain the more accurate spectrum, the error must be corrected. According to the imaging principle analysis oWhen the large aperture static imaging spectrometry (LASIS) was used in spaceborne remote sensing, the spectrum could not be well recovered from the interferogram with detector lateral fringe error. In order to obtain the more accurate spectrum, the error must be corrected. According to the imaging principle analysis of LASIS, the imaging model with lateral fringe error was given, and the error correction method was presented. Finally, the error correction method was validated with the data acquired by LASIS system. The results indicated that the error was commendably corrected by the method mentioned above, and the accuracy of recovered spectrum was evidently improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1137 (2012)
Precision Measurement of the Birefringence of Quartz Crystal at 1 310 nm Based on the Spectroscopic Ellipsometer
HAN Pei-gao, HAO Dian-zhong, SONG Lian-ke, SU Fu-fang, SHI Meng, L Ting-fen, WU Fu-quan, and LI Guo-hua
In order to get the precision measurement of birefringence of quartz crystal at the communication wavelength1310nm, based on the principle of precision measurement of phase difference between P and S polarized lights of spectroscopic ellipsometer, a method for precision measurement of birefringence of crystal was desigIn order to get the precision measurement of birefringence of quartz crystal at the communication wavelength1310nm, based on the principle of precision measurement of phase difference between P and S polarized lights of spectroscopic ellipsometer, a method for precision measurement of birefringence of crystal was designed through the analysis of the Jones matrix under the transmission mode, and the precision measurement of birefringence of quartz crystal at 1 310 nm at room temperature (22 ℃) was made, the measuring results and error analysis show that the precision reached 10-6 level, this is the most precise birefringence parameter available, and it is of important significance for the improvement of designing precision of phase retardation devices of quartz..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1142 (2012)
Information Extraction of the Chang’E-1 Interference Imaging Spectrometer (IIM) 2C Data
WANG Xiang, CHEN Jian-ping, LI Jian-feng, SHI Rui, and WU Zhao
Through analysis of solar azimuth of Chang’E-1 IIM data, the data of high-angle were chosen to do radiometric calibration. The method of neighbourhood averaging and neighbourhood weighted averaging were adopted to repaire original data which contains bad points and bands. Because of interference imaging spectrometer’s Through analysis of solar azimuth of Chang’E-1 IIM data, the data of high-angle were chosen to do radiometric calibration. The method of neighbourhood averaging and neighbourhood weighted averaging were adopted to repaire original data which contains bad points and bands. Because of interference imaging spectrometer’s inherent problem and CCD array gain distortion, the image displays discontinuity of transverse response. By using the method of subspace maximum eigenvalue to cablibrate image, the statistical result of processed images shows homogeneity on intensity of radiance. The empirical linear method was adopted to calibrate IIM data absolutely. Meanwhile, in order to correct bias coefficient of data which has been calibrated and de-noised , the method of wavelet transform was adopted to modificate data of radiometric calibration for the first time, the final available IIM 2C data were confirmed. Compared with the data which has been accredited, the analysis proposal of IIM 2C data was established. Then the first reflectivity image of the lunar nearside based on Chang’E-1 IIM 2C was accomplished ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1145 (2012)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 4, 1 (2012)
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