Journals >Spectroscopy and Spectral Analysis
Contents
2016
Volume: 36 Issue 4
69 Article(s)
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Research Article
Study of the Laser Absorption Characteristics of CO2 Laser-Pulsed GMAW Hybrid Welding Based on Spectral Diagnosis Technique
ZHANG Wang, LI Fang, LI Min, HUA Xue-ming, and CAI Yan
During the process of laser-arc hybrid welding, the metal vapor from the wire end has great influence on the electron number and the particles in the plasma, which changes the absorption of the laser irradiation and the energy input to workpiece.In this paper, an optical emission spectroscopy system was employed to estDuring the process of laser-arc hybrid welding, the metal vapor from the wire end has great influence on the electron number and the particles in the plasma, which changes the absorption of the laser irradiation and the energy input to workpiece.In this paper, an optical emission spectroscopy system was employed to estimate plasma temperature and the electron number densities distribution. A high speed camera was used to analyze the plasma shape behavior. By using the Beer-Lambert law, the laser absorption rate under different welding mode was calculated. The result shows that the metal vapor from the wire tip lead the electron density increase, and it make the laser energy absorption rates decreased..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 913 (2016)
Terahertz Spectroscopic Study on the Property of Epoxy Resin Adhesive
ZHANG Jin, CUI Hong-liang, SHI Chang-cheng, CHEN Jian-dong, ZHANG Zi-yin, HAN Xiao-hui, and MA Yu-ting
Epoxy resin is an important adhesive applied in the manufacturing processes of fiber reinforced polymer (FRP) composites. Terahertz (THz) time-domain spectroscopy (TDS) technology is an effective supplementary method for nondestructive evaluation (NDE) of FRP composites. As one of the most important parameters for epoxEpoxy resin is an important adhesive applied in the manufacturing processes of fiber reinforced polymer (FRP) composites. Terahertz (THz) time-domain spectroscopy (TDS) technology is an effective supplementary method for nondestructive evaluation (NDE) of FRP composites. As one of the most important parameters for epoxy resin, different curing temperature can affect the properties of epoxy resin. In this paper, we carry out systematic investigations on THz transmission properties of epoxy resin cured respectively under room temperature and high temperature with THz TDS technology. At the same time, the authors extract the refractive indices and absorption coefficients of epoxy resin, and make comparisons d. As shown in the experiments, the epoxy resin samples cured under room temperature have no bubble, whereas there are some micro-bubbles in the samples cured under high temperature, which reduce the sample density. Hence, the refractive index and absorption coefficient of epoxy resin cured under room temperature are both greater than those cured under high temperature. The difference of refractive index of different samples cured under the same condition is not significant. In addition, the difference of absorption coefficient of different samples cured under room temperature is also slight. However, the difference of absorption coefficient of different samples cured under high temperature gradually increase within the frequency from 0.6 to 1.5 THz, which is mainly due to the heterogeneous distribution of the bubbles in the different samples cured under high temperature. Moreover, the absorption coefficient of epoxy resin prepared under both curing temperatures gradually increases with the frequency, and there is no obvious absorption peak. Finally, because of the existence of Fabry-Pérot interference, the power transmission ratio of thicker epoxy resin samples may be greater than thinner samples at the resonant frequency. This research is of great significance for the THz NDE of FRP composites..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 919 (2016)
Study on the Measurement and Optimization of Soybean Oil Optical Spectrum in THz Range
ZHOU Sheng-ling, ZHU Shi-ping, LI Guang-lin, HUANG Jie, and YANG Ya-ling
Terahertz time-domain spectroscopy is an effective technique that applies spectral measurements by using an ultra fast femtosecond laser. These unique properties of terahertz waves make it an effective nondestructive testing technology. Currently, it has been applied in many fields. However, when we calculate the opticTerahertz time-domain spectroscopy is an effective technique that applies spectral measurements by using an ultra fast femtosecond laser. These unique properties of terahertz waves make it an effective nondestructive testing technology. Currently, it has been applied in many fields. However, when we calculate the optical parameters of the sample especially for liquids, from data obtained with time-domain spectroscopy, a common problem occurred is spurious oscillation, which is caused by the Fabry-Perot effect in sample, containers and optical elements. In order to obtain high frequency resolution and accurate sample optical parameters, it is necessary to use some signal processing techniques properly. In this paper, we improved de-convolution algorithm and presented a simple algorithm based on the traditional optical parameter calculation model. Considering the nonlinear absorption of THz wave by samples, containers, emitters or detectors, a THz time-domain trace containing echo signals can be represented as a convolution of the primary peak, some delta functions and nonlinear transfer functions. By analyzing equations, spurious oscillations in the THz spectra result from echo signals can be removed or reduced effectively. The use of the method is discussed and the transmission spectrum of soybean oil in 0.2~2.0 THz range is measured accurately by terahertz time-domain spectroscopy. Experiments show that, this method can effectively remove the frequency oscillation caused by echoes. This algorithm is not affected by the tested object, and is equally applicable to other liquid measurements in THz range. What’s more, compared with the traditional method of main pulse interception, this algorithm under the same experimental conditions can effectively improve frequency resolution of soybean oil in 0.2~2.0 THz region, from 50 GHz to less than 10 GHz. At the end of this paper, the causation of remaining oscillation in sample spectrum and absorption spectrum were deeply analyzed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 924 (2016)
Study on the Samples of Weathered Red-Bed Mudstone Based on THz-TDS
LI Ming-liang, CHANG Tian-ying, and CUI Hong-liang
The weathering universally takes place in red-bed mudstone slope, which is not completely solved till now. Under the influence of geotechnical weight force, vibration, and other factors, unsteady red-bed mudstone slope caused due to weathering often lead to harmful deformation and failure, resulting in collapse of geolThe weathering universally takes place in red-bed mudstone slope, which is not completely solved till now. Under the influence of geotechnical weight force, vibration, and other factors, unsteady red-bed mudstone slope caused due to weathering often lead to harmful deformation and failure, resulting in collapse of geological disasters such as landslides, falling rocks and mudslides. Weathering depth is the vertical distance after the rock burst produced inside the fracture surface micro cracks or micro-cracks in the weathering zone extends to the interior of the rock. Weathering depth can provide an important basis for red-bed mudstone slope treatment. The rock core was obtained by using the core drilling machine in the typical red-bed mudstone slope. Terahertz time-domain spectroscopy is a new spectroscopy approach to characterize material based on terahertz pulse. Terahertz time-domain spectroscopy is used to measure the terahertz transmission spectroscopy of sample obtained. The THz transmission spectra of samples are being analyzed. Only minor differences are found among the transmission spectra of different samples, and there are not characteristic absorption peaks been observed. To obtain weathering depth of sampling site, an intelligent and efficient SVM model of the transmission spectra of samples is employed to distinguish and predict the depth. Compared with the actual depth, the relative error is less than 7.09%. The results showe that THz spectroscopy based on support vector machine (SVM) model can effectively distinguish samples and the predict depths, which can provide an important reference for the red-bed mudstone slope treatment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 929 (2016)
Spectroscopic Study on a Direct-Current Driving Plasma Jet in Argon at Atmospheric Pressure
LI Xue-chen, DI Cong, BAO Wen-ting, ZHANG Chun-yan, and LI Ji-yuan
With a discharge device in a hollow-needle and plate electrode configurations, an atmospheric pressure uniform plasma plume is generated by DC voltage excitation in the ambient air with argon as working gas. The plasma plume is a pulsed discharge despite a direct current voltage is applied through measurements by opticWith a discharge device in a hollow-needle and plate electrode configurations, an atmospheric pressure uniform plasma plume is generated by DC voltage excitation in the ambient air with argon as working gas. The plasma plume is a pulsed discharge despite a direct current voltage is applied through measurements by optical and electrical methods. In order to explain the formation mechanism of the pulse, spatially resolved signals emitted from the plume were detected. It was found that the plasma plume denoted as the luminous layer propagates (a plasma bullet) from the hollow needle to the plate electrode except for the corona discharge in the vicinity of the hollow needle tip. Optical emission spectroscopy is used to investigate the excited electron temperature of the plasma plume as a function of the applied voltage or the spatial distribution of the excited electron temperature. The results show that the excited electron temperature (about 3 eV) increases with increasing applied voltage. Moreover, it increases with the increasing distance along the gas flow under constant voltage..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 934 (2016)
Study of IR Property of Glow Discharge Polymer (GDP)
WEN Cheng-wei, YIN Jian, YU Ming-ming, LI Hai-rong, XIA Li-dong, HE Zhi-bing, and LIANG Jian-hua
To achieve the object of NIF ignition , it is required to prepare high density fuel targets . For DD layer, IR-layering can be used to improve its surface roughness. In this paper, glow discharge polymer (GDP) flat films and capsules were synthesized. The IR absorptive properties of GDP were thoroughly studied by usingTo achieve the object of NIF ignition , it is required to prepare high density fuel targets . For DD layer, IR-layering can be used to improve its surface roughness. In this paper, glow discharge polymer (GDP) flat films and capsules were synthesized. The IR absorptive properties of GDP were thoroughly studied by using infrared spectrometer and microscopy while the extinction coefficients of GDP flat film at specific wavelengths were obtained. By comparing absorption properties of flat films and capsules, it is found that thermal treatments can lower the OH content of GDP and thus improve IR layering of DD ice. Finally, the needed IR power of integration sphere were estimated by using data obtained for future DD layering experiments in this paper. The results have laid a solid foundation for the implementation of DD IR layering..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 939 (2016)
Study on the Measurement of Infrared Spectrum for Discontinuous Sample
BAI Sha-sha, and WANG Hai-shui
The samples to be measured with infrared instrument are usually required to be homogeneous. However, discontinuous sample is quite common in the real infrared measurements, such as, high viscosity liquids containing air bubbles. In this paper, the spectral distortion of discontinuous sample was analyzed with simple theThe samples to be measured with infrared instrument are usually required to be homogeneous. However, discontinuous sample is quite common in the real infrared measurements, such as, high viscosity liquids containing air bubbles. In this paper, the spectral distortion of discontinuous sample was analyzed with simple theoretical simulation and experimental examples quantitatively. The spectral properties of the discontinuous sample were studied and discussed systematically. Both theoretical computation and experimental results demonstrated that the infrared spectrum of a discontinuous sample was highly similar to that of the uniform sample if suitable experimental conditions were adopted. Our results showed that if infrared samples can be prepared to be thin enough, the infrared spectrum of the discontinuous sample can fulfill the requirements of analysis work nearly perfectly..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 943 (2016)
Analysis and Identification of H. rhamnoides subsp. sinensis Harvested From Different Producing Areas by FTIR Spectroscopy
LIU Yue, LI Jing-yi, FAN Gang, LIU Chuan, SUN Su-qin, SU Yong-wen, JIANG Dao-feng, ZHANG Yi, and TU Ya
The accurate identification of traditional Chinese medicine (TCM) which collected from different producing areas is important for its quality control and clinical effects. In the present study, Fourier transform infrared spectroscopy (FTIR) combined with second derivative spectra were used to identify and analyze H. rhThe accurate identification of traditional Chinese medicine (TCM) which collected from different producing areas is important for its quality control and clinical effects. In the present study, Fourier transform infrared spectroscopy (FTIR) combined with second derivative spectra were used to identify and analyze H. rhamnoides subsp. sinensis from different producing areas. The characteristic absorption peaks, including 2 925, 2 854, 1 743, 1 541 and 1 173 cm-1 belonging to fatty acids, flavonoids and saccharides appear in all 20 samples. But the absorption peak intensities and locations varied due to the different geographical regions. The results also showed that the absorption peaks at the range of 3 429～3 336 and 1 744 cm-1 were important characteristic absorption peaks which can identify H. rhamnoides subsp. sinensis from different producing areas. Also, absorption peaks at 1 030 and 1 516 cm-1 further confirmed the existence of flavonoids in all samples by comparing the second derivative infrared spectra in the range of 1 800～1 000 cm-1. However, the samples’ differences can be intuitively found around peaks 1 711, 1 476 cm-1 and ranges from 1 689～1 515 and 1 400～1 175 cm-1. The results demonstrated that FTIR was a simple, convenient, fast and intuitive approach to identify and analyze H. rhamnoides subsp. sinensis from different producing areas. This method provides foundations for the analysis of chemical compositions and quality control for the TCM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 948 (2016)
Effects of Red Light-Emitting Diode (LED) on the Postharvest Yellowing Change of Broccoli
ZHANG Na, YAN Rui-xiang, GUAN Wen-qiang, and WANG Chao
As an important factor affecting the growth and development of plants, light gives wide range regulating effects on physiological metabolisms, photosynthesis characteristic, quality and aging of plants during the growth . However, the research whether light can improve the quality of fruits and vegetables and prolong tAs an important factor affecting the growth and development of plants, light gives wide range regulating effects on physiological metabolisms, photosynthesis characteristic, quality and aging of plants during the growth . However, the research whether light can improve the quality of fruits and vegetables and prolong the storage period of is rarely reported home and abroad. Three monochromatic light , red, blue and green were used to the irradiation of broccoli. It was found that the inhibitory effect of red light could inhibit yellowing of postharvest broccoli better than that of blue light while green light could accelerate the yellowing, therefore this paper focused on the yellowing inhibitory effect of LED monochromatic red light on postharvest broccoli. The LED monochromatic red light with wavelength (625±5)nm, light intensity (100±5)Lx was used to provide continuous irradiation to broccoli with no light treatment as control. The results showed that: LED monochromatic light could inhibit the increase of chromatic aberration L value. The chromatic aberration -a/b value was maintained and the chlorophyll degradation was delayed. Meanwhile, the broccoli commodity was effectively maintained because of the delay of the respiration peak and the reduction of respiratory intensity as well as ethylene release rate . Correlation analysis showed that, after red LED monochromatic light treatment of broccoli, a positive very significant correlation (p<0.01) was found between the ethylene release rate and yellowing index. Compared with conventional no-light, treatments of LED monochrome red could extend the storage period around 5d for broccoli, and the results can provide a theoretical basis for cold storage of Broccoli..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 955 (2016)
Study on the Estimation Algorithm of the Temperature Based on Mid-Wave Infrared Remote Sensing
FANG Zheng, OUYANG Qi-nan, ZENG Fu-rong, CHEN Si-yuan, and MA Sheng-lin
Since objects above absolute zero agree with the Plank law, the objects’ temperature is reflected by the infrared radiation. With fast response and high resolution, temperature estimation based on mid-wave infrared remote sensing could realize the temperature measurement for small, high-speed and touch-free objects. A Since objects above absolute zero agree with the Plank law, the objects’ temperature is reflected by the infrared radiation. With fast response and high resolution, temperature estimation based on mid-wave infrared remote sensing could realize the temperature measurement for small, high-speed and touch-free objects. A new optical system for infrared (IR) image-spectrum integration remote sensing was used to acquire infrared emission spectra from different temperatures of metal. With this basis, we extracted four appropriate spectral features which were the center of gravity position, peak position, the value of wavelength λ1 and the value of wavelength λ2 from the training samples. The relationship between temperature and these features was studied. A multiple linear regression model was established to estimate the temperatures from the spectra. The experimental results showed that, the method could distinguish hot objects with obvious temperature differences. The absolute error was less than 30 ℃ in the experimental temperature range. The accuracy was 98% in the range that the measurement error was less than 20 ℃, which was better than the 2% precision of the general system with the complex strict emissivity, atmospheric transmittance, environmental equivalent radiation temperature and some other parameters. This method could measure the temperature of the remote objects in a simple and effective way, and so could expand the application field of temperature estimation based on infrared remote sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 960 (2016)
Study on the Analysis of the Proportion of Mixed Samples with Near Infrared Spectroscopy and Non-Negative Coefficients Regression
LI Xue-ying, SHU Ru-xin, LUAN Li-li, LI Kai, YANG Kai, LI Jun-hui, ZHAO Long-lian, ZHANG Ye-hui, and ZHANG Lu-da
In the process of practical production, it is important to accurately analyze the proportion of mixed samples with high speed, which plays a great role for quality control and formulation design in food and agricultural processing. Traditional solution is to build statistical model with a large number of representativeIn the process of practical production, it is important to accurately analyze the proportion of mixed samples with high speed, which plays a great role for quality control and formulation design in food and agricultural processing. Traditional solution is to build statistical model with a large number of representative samples, which is both labor-intensive and time-consuming. In this paper, the proportion of alcohol and acids mixed samples, and their dilute solution mixed samples(used carbon tetrachloride (CCl4) which has no near-infrared absorption characteristics as the solvent medium), as well as sheet tobacco leaf mixed samples are respectively analyzed by using near infrared spectroscopy, SG smooth and non-negative coefficients regression, which verifies the feasibility of analyzing the proportion of the mixed samples. The results show that, the analytic proportion of transmission spectra of alcohol and acids according to non-negative coefficients regression is closer to actual molar proportion with result error less than 4%. The result of the dilute solution is much better with error less than 4%. The analytic proportion of diffuse reflectance spectra of sheet tobacco leaf according to non-negative coefficients regression is highly accurate with error less than 10%. In the meantime, it has a highly consistency between actual spectra and analytic spectra of mixed samples; and the result of F-test and T-test shows that there is no significant difference between them and the confidence level is 0.01. It has the reliability of analytical proportion in theory. With the spectral data of several pure samples, the proportion of mixed samples can be thus analyzed, which has a good application prospect for quality control and formulation design in food and agricultural processing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 967 (2016)
Real-Time Monitoring Method for Pedicle Screw Fixation Surgery Based on Near-Infrared Spectrum and Computer Tomography Images
LIU Yang-yang, WANG Yu-yan, GAO Hui, QIAN Zhi-yu, XIE Jie-ru, and LI Wei-tao
Spine is one of the most important organs in the human body. One of the most commonly used method for the treatment of spinal diseases is the internal fixation and accurate placement of pedicle screw, which is a key factor of spinal surgery. However, due to the large differences as to the appearance of pedicles, it is Spine is one of the most important organs in the human body. One of the most commonly used method for the treatment of spinal diseases is the internal fixation and accurate placement of pedicle screw, which is a key factor of spinal surgery. However, due to the large differences as to the appearance of pedicles, it is hard to place the pedicle screw precisely, which will cause complication. Therefore, to find a new real-time intra-operative monitoring method with navigation is the direction of clinical application research. In this paper, a new method was firstly proposed. This method combined computer tomography (CT) values and near-infrared spectroscopy (NIRs) measurement data to guide the PS placement, and the relationship between NIRs parameters and CT values along the PS trajectory in vertebrae was investigated. First, we took pig vertebrae as samples and different puncture paths were planned. Second, a near-infrared monitoring device was utilized in experiments of fresh pig vertebrae to acquire the best NIRs monitoring pattern factors. Finally, the correlation function between NIRs data and CT values pattern factors was obtained. The results showed that CT values have a linear relationship with NIRs monitoring pattern factors, which provide references for real-time monitoring method in pedicle screw fixation surgery. This model can be applied in monitoring the pedicle screw implantation and alarming. The proposed method will be potential in improving the accuracy of PS placement and reduce the risk caused by the misplacement of pedicle screw..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 972 (2016)
Study on the Fast Quantitative Analysis of the Content of DME Adulterated in LPG
ZHU Zhi-qiang, YUAN Hong-fu, HU Ai-qin, SONG Chun-feng, LI Xiao-yu, and WU Ming-qing
A new analytical method of analyzing dimethyl ether (DME) content in liquefied petroleum gas (LPG) is proposed in this paper. An unsolved problem about quick detection of the composition of LPG has been settled with this method. A set of precise preparation apparatus for DME/ LPG solution and a set of quickly analyticaA new analytical method of analyzing dimethyl ether (DME) content in liquefied petroleum gas (LPG) is proposed in this paper. An unsolved problem about quick detection of the composition of LPG has been settled with this method. A set of precise preparation apparatus for DME/ LPG solution and a set of quickly analytical system of LPG based on near infrared technology were designed. The analytical equipment can be conveniently connected to the sampling cylinder because it can bear 3.5 MPa pressure. Oblique projection algorithm was used to separate the pure spectra of DME from that of the LPG’s solutions. The standard curve of the concentration of DME (c) has been built by using the Intensity (I) of pure signal of DME in the LPG solution and the concentrations. The correlation coefficient of the equation is 0.999 4. The result of external validation shows that the relative error is less than 2.0%. The new method has the advantages such as fast, easy and noneed of expensive multivariate modeling..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 978 (2016)
Study on Non-Destructive Detection Method for Egg Freshness Based on LLE-SVR and Visible/Near-Infrared Spectrum
DUAN Yu-fei, WANG Qiao-hua, MA Mei-hu, LU Xi, and WANG Cai-yun
The freshness of egg is an important index to reflect the internal quality. In order to achieve non-destructive detection of freshness, micro fiber spectrometer was used to sample 550～950 nm transmittance spectra of eggs which performed quantitative analysis with haugh unit of eggs. Different pretreatment was combined The freshness of egg is an important index to reflect the internal quality. In order to achieve non-destructive detection of freshness, micro fiber spectrometer was used to sample 550～950 nm transmittance spectra of eggs which performed quantitative analysis with haugh unit of eggs. Different pretreatment was combined with partial least squares regression(PLS) and support vector regression(SVR) respectively to find that first derivative combined with SVR predicted better than others through comparison, and it was better to model by SVR than by PLS. In order to improve efficiency and decrease adverse effects of useless information for modeling, the linear dimensionality reduction with principal component analysis (PCA) and the nonlinear dimensionality reduction with locally linear embedding(LLE) were used for the data of first derivative respectively. It indicated that LLE was better than PCA after comparison, and the correlation coefficient of calibration and prediction were 92.2%, 91.1%, and the root mean square error were 7.21, 8.80. The root mean square error of cross validation decreased 0.79.The experimental result illustrated that the nonlinear model of LLE combined with SVR improved predictive performance of egg freshness. It is feasible for the detection of visible/near-infrared spectrum of egg freshness to apply this method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 981 (2016)
Micro-Raman Spectral Characteristics and Implication of FeS2 from Metamorphic Belt between Coal and Intrusion in Wolonghu Coal Mine of Anhui Province, China
AN Yan-fei, ZHENG Liu-gen, SUN Qian-wen, JIANG Ya-lin, WANG Cheng-jie, WANG Rong-rong, and NIU Kun
Some FeS2 samples among metamorphic belt between coal and intrusion from Wolonghu mine in the north of Anhui Province were retrieved to characterize the signature of Raman Spectral. The results show that, all Raman data of different samples can be divided into 3 types as Ⅰ, Ⅱ and Ⅲ according to distinct differences of Some FeS2 samples among metamorphic belt between coal and intrusion from Wolonghu mine in the north of Anhui Province were retrieved to characterize the signature of Raman Spectral. The results show that, all Raman data of different samples can be divided into 3 types as Ⅰ, Ⅱ and Ⅲ according to distinct differences of in Raman mode (M), Raman shift (Δν) and scattering intensity (Ⅰ). There are five strong scattering modes including high value Eg (1.16~1.59×103), high value Ag (2.33~2.53×103) and low value Tg (0.20~0.27×103) in typeⅠand only former three modes in type Ⅱ although the value of Eg, Ag and Tg are similar between them. While there are only two modes of high value Eg about 327.6~328.8 cm-1 and low value Ag 389.0~390.1 cm-1. Our analyses indicate that type Ⅰ samples must be mixed crystal of pyrite and natural coke for the former three peaks are same to deformation and stretching vibration of Fe-［S2］2- and stretching vibration of S—S in pyrite, while the latter two are similar to the vibration of Tiny graphite crystals and stretching vibration of C—C among graphite crystal from Raman data. And typeⅡsample may be pyrite for typical pyrite Scattering peak and Type Ⅲ sample possibility are low-temperature crystalloblastic of pyrite for Marcasite spectrum features in Raman. Further analysis also showed that the formation pressure of typeⅠ and Ⅱ are the same while type Ⅲ samples formed in low pressure for Raman scattered intensity of typeⅠand Ⅱ are similar, and type Ⅲ samples is obviously lower than the former two. And the formation temperature of typeⅠ, typeⅡ and type Ⅲ significantly decreased in turn for Ag peak of them are turn to high frequency about 4.4~6.7, 4.5~8.4cm-1 respectively compared with the former. Thus, The authors’ studies suggest that pyrite samples from Metamorphic coal and metamorphic zone in Wolonghu coal mine are products in high temperature, but samples from Magmatic rocks are Marcasite formed at low temperature..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 986 (2016)
Study on the Raman Spectrum, Thermal Stability and UV-Vis Optical Absorption of Amorphous Peroxpolytungstic Acid
ZHANG Feng, DONG Ya-bo, and MENG Fan-cheng
Peroxpolytungstic acid (PPTA) is one of the important precursors to synthesize nanostructured tungsten oxides with the chemical routes. In this paper, PPTA sol, being prepared with H2O2, W and C2H5OH, was placed at room temperature for a long time till it was jellified naturally and then was dried at 120 ℃ for 3 hours Peroxpolytungstic acid (PPTA) is one of the important precursors to synthesize nanostructured tungsten oxides with the chemical routes. In this paper, PPTA sol, being prepared with H2O2, W and C2H5OH, was placed at room temperature for a long time till it was jellified naturally and then was dried at 120 ℃ for 3 hours for this investigation. Structures, thermal stability and optical UV-Vis absorption of the samples have been investigated by XRD, SEM, Raman, TG/DSC and UV-Vis spectrum, respectively. The wide peaks from XRD indicate that the sample is amorphous. The Gaussian fitting for these XRD peaks indicates that the sample is the composite of tungsten oxides and tungsten oxide hydrates. SEM indicates that the sample possesses the morphologies of the nano-particles with the sizes of about 50~100 nm and the nano-flakes with the thickness of about 50 nm. The Gaussian fitting of the wide Raman peaks illustrates that the sample possesses the obvious the modes of symmetrical O—W—O stretching, asymmetrical O—W—O stretching and WO vibration accompanied with the modes of symmetrical O—W—O bending, asymmetrical O—W—O bending and the adsorptive water vibration. This fact further indicates that the sample is composed of the amorphous tungsten oxides and tungsten oxide hydrates. Analysis on the TG/DSC curves indicates that PPTA gels possess four different thermal dynamic processes with increasing the treatment temperature from 120 to 500 ℃: (1) the slow crystallization of PPTA (120~165 ℃), (2) the dissociation of adsorptive H2O2 and the desorption of adsorptive H2O (165~236 ℃), (3) the quick decomposition of tungsten oxide hydrate (236~287 ℃) and (4) the crystallization and phase transformation of the final products WO3 (287~500 ℃). Optical absorption of PPTA gels happens in the range of 350~600 nm, where the intensity of the optical absorption gradually increases and finally reaches the saturation with the increase of photon energy. The optical band gap was estimated to be about 2.25 eV, being obviously lower than the known values for WO3 and H2WO4 (2.48~3.50 eV). The key factors for the low gap value of the composite can be attributed to the molecular water, the oxygen defects and the structural distortion..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 991 (2016)
Study on the Structure and Photoluminescent Properties of Mono-Zn(Ⅱ) and Di-Cu(Ⅰ) Complexes Constructed from Nitrogen Heterocyclic Ring Ligand
XU Yang, QIANG Liang-sheng, FAN Rui-qing, WANG Ping, and YANG Yu-lin
The mononuclear Zn(Ⅱ) complex ［Zn(2,6-PDA)(phen)H2O］·H2O (1) and binuclear Cu(Ⅰ) complex{［Cu(μ-Ⅰ)(phen)H2O］·H2O}2 (2) (2,6-H2PDA=2,6- pyridinedicarboxylic acid, phen=1,10- phenanthroline monohydrate) have been prepared with hydro-thermal synthesis method. These complexes have been characterized with single-crThe mononuclear Zn(Ⅱ) complex ［Zn(2,6-PDA)(phen)H2O］·H2O (1) and binuclear Cu(Ⅰ) complex{［Cu(μ-Ⅰ)(phen)H2O］·H2O}2 (2) (2,6-H2PDA=2,6- pyridinedicarboxylic acid, phen=1,10- phenanthroline monohydrate) have been prepared with hydro-thermal synthesis method. These complexes have been characterized with single-crystal X-ray, elemental analysis, and IR spectroscopy. The fluorescence spectra of 1 and 2 are studied in solid-state and dimethyl sulfoxide (DMSO) solution. The maximum absorption peak of 1 and 2 are at 253 nm and 242 nm respectively, which are red shift to that of the phen ligand with inceased intensity. It may be assigned to the intraligand π→π* transition of the phen ligand that is modified by the Zn(Ⅱ) or Cu(Ⅰ) ions. On the basis of the coordination, the absorption of organic ligands in the ultraviolet region is increased, which is better for the energy absorption of the ligand. 1 and 2 all showed blue light emission. The emission peak of 1 and 2 have experienced a red shift (ca. 55 and 23 nm) in the solid state (λem = 407, 434, 467 nm for 1, 442, 469, 501 nm for 2) compared to in DMSO solution (λem = 361, 379, 392 nm for 1, 422, 443, 461 nm for 2). The red shift phenomenon can be attributed to the π-stacking of the aromatic rings and other intermolecular Interactions in these molecules in the solid state. Especially, the strong Cu(Ⅰ)…Cu(Ⅰ) interaction of 2 can decrease the HOMO—LUMO energy gap with the red-shifted emission wavelength..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 996 (2016)
Fabrication and Characterization of Planar Luminescent Solar Concentrator Waveguides Based on LR305 Dye
LI Xing, WU Wei-xia, ZHANG Chun-mei, ZHANG Ao, LUO Yun-peng, ZHANG Zhong-wen, DENG Rui-jiang, ZOU Cheng, and MENG Tao
Photovoltaic power generation is one of the best ways to utilize solar energy, but the cost of electricity is very high. To reduce the cost of photovoltaic power generation, in this paper, a type of planar luminescent solar concentrator waveguides based on Lumogen F Red 305 (LR305) dye with each size of 50 mm×50 mPhotovoltaic power generation is one of the best ways to utilize solar energy, but the cost of electricity is very high. To reduce the cost of photovoltaic power generation, in this paper, a type of planar luminescent solar concentrator waveguides based on Lumogen F Red 305 (LR305) dye with each size of 50 mm×50 mm×5 mm was proposed with radical polymerization method. The optical properties and photo-electricity outputs of the waveguides were characterized..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1001 (2016)
Study on Fluorescence Properties of Flavanone and Its Hydroxyl Derivatives
LI Wen-hong, CAO Jin-jin, LU Rui, CHE Cui-xia, and WEI Yong-ju
Flavanone derivatives are important active ingredients of natural medicine, so the synthesis of these compounds is one of the research hotspots of organic synthesis. Nevertheless, there is little research on fluorescence properties of these compounds up to now. Fluorescence properties of flavanone and 6 kinds of hydroxFlavanone derivatives are important active ingredients of natural medicine, so the synthesis of these compounds is one of the research hotspots of organic synthesis. Nevertheless, there is little research on fluorescence properties of these compounds up to now. Fluorescence properties of flavanone and 6 kinds of hydroxyl derivatives are studied in this paper. It is found that aqueous solutions of flavanone (FV), 7-hydroxyflavanone (7HF) and 6-hydroxyflavanone (6HF) have fluorescence, but aqueous solutions of 2’-hydroxyflavanone (2’HF), 4’-hydroxyflavanone (4’HF), naringenin and pinocembrin basically have no fluorescence. In three dimensional fluorescence spectra, excitation wavelengths λex of FV are located at 235, 265 and 340 nm, emission wavelength λem is at 386 nm; λex of 7HF are at 230, 276 and 315 nm, λem is at 391 nm; λex of 6HF are at 260 and 356 nm, em is at 482 nm. Influences of pH on fluorescence of FV, 7HF and 6HF are studied, and the reasons of pH affects on fluorescence are discussed from the viewpoint of molecular structure. The UV-absorption spectra of 7HF and 6HF at different pH are studied, and the proton ionization constants (pKa) of 7HF and 6HF are determined respectively to be 7.26±0.05 and 9.90±0.02, by a pH-absorption method. Influences of solvent (methanol) on fluorescence of FV, 7HF and 6HF are studied, and find that the fluorescence of FV and 7HF in methanol are weaker than that in water, but the fluorescence of 6HF in methanol is much stronger. In ordered media (SDS, CTAB and β-CD), fluorescence of FV and 7HF decreased than that in water, but the fluorescence of 6HF enhanced in the media of β-CD or CTAB. Using quinine sulfate or L-tryptophane as reference, fluorescence quantum yields of FV and 7HF aqueous solutions are measured to be 0.057 and 0.012, respectively; fluorescence quantum yields of 6HF in methanol or in aqueous solution containing 1.62 mg·mL-1 β-CD are measured to be 0.064 or 0.012, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1007 (2016)
Study of the Detection of Histidine Based on “On-Off” Fluorescence Probe of Carbon Dots
TAO Hui-lin, LIAO Xiu-fen, SUN Chao, ZHOU Su-lian, ZHONG Fu-xin, YI Zhong-sheng, and LU Yan-qun
An new type of switch “On-Off” fluorescence probe was constructed based on fluorescence carbon dots as a novel strategy to analyze trace histidine(His) which was proposed for the first time. In water solution with pH 7.6, the fluorescence of CDs was quenched with Ru3+ due to the formation of ground state compound throuAn new type of switch “On-Off” fluorescence probe was constructed based on fluorescence carbon dots as a novel strategy to analyze trace histidine(His) which was proposed for the first time. In water solution with pH 7.6, the fluorescence of CDs was quenched with Ru3+ due to the formation of ground state compound through electrostatic attraction, and the system was thus “turned-off”. The fluorescence intensity of CDs was “turned-on” due to the competition between His and Ru towards the surface of CDs. The effect of critical parameters including pH, buffer solutions, reaction temperature and time needed to grow the fluorescence intensity of CDs was studied. Results show thatin water solution with pH 7.6, and when the temperature was between 20~25 ℃, the fluorescence intensity of the released CDs displayed a linear relationship in the range of (6.5~219.3)×10-6 mol·L-1 of captopril. Lower limit of detection for His, at the signal-to-noise ratio of 3/(3δ), was 2.15×10-6 mol·L-1. The methodology was successfully applied for the determination of His in Compound Amino Acid Injections, with the RSD≤2.07%, and the recovery rate was between 95.7%～102.4%. The result of the experiment was satisfactory. On the one hand, the excellent optical character CDs was acted as “On-Off” fluorescence probe, which could be extent the application of CDs, on the other hand, the excellent performance of the proposed fluorescence probe shows that this method possesses the potential for practical application..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1013 (2016)
Detection of Trace Lead (Ⅱ) with CdZnTe Quantum Dots Capped with Polyethyleneimine as A Fluorescence Probe
CHEN Yan-qing, and XIE Yu
Water-soluble CdZnTe quantum dots (QDs) were firstly synthesized by using 3-mercaptopropionic acid (MPA) as modifier in aqueous phase. Then, CdZnTe quantum dots were capped with polyethyleneimine (PEI) with electrostatic interaction and condensation reaction between carboxyl group on the surface of QDs and amino group Water-soluble CdZnTe quantum dots (QDs) were firstly synthesized by using 3-mercaptopropionic acid (MPA) as modifier in aqueous phase. Then, CdZnTe quantum dots were capped with polyethyleneimine (PEI) with electrostatic interaction and condensation reaction between carboxyl group on the surface of QDs and amino group of PEI, and several metal ions were tested to check if they affect the fluorescence properties of CdZnTe QDs in the paper. A novel method to detect trace Pb2+ has been developed based on the selective fluorescence quenching Pb2+ to PEI-CdZnTe QDs. Fluorescence quenching effect of PEI-CdZnTe QDs had been studied by increasing the Pb2+ concentration. The study results show that fluorescence quenching process of Pb2+ can be described well by Stern-Volmer fluorescence quenching equation. There is a good linear relationship between the fluorescence intensity F0/F and the concentration of Pb2+ when the concentration of Pb2+ is in the ranges of 0.05~3.0 μg·mL-1. The linear correlation coefficient and the detection limits are 0.998 8 and 0.01 μg·mL-1, respectively. The proposed fluorescence method of detection is simple, rapid and sensitive, which has been successfully applied to the detection of Pb2+ in tap water..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1017 (2016)
The Discrimination of Chinese Strong Aroma Type Liquors with Three-Dimensional Fluorescence Spectroscopy Combined with Principal Component Analysis and Support Vector Machine
XU Rui-yu, ZHU Zhuo-wei, HU Yang-jun, ZHANG Yi, and CHEN Guo-qing
In this paper, a method for discrimination of different bands liquor with strong aroma type based on three-dimensional fluorescence spectrum technology was developed. Firstly, the three-dimensional fluorescence spectra of seven different brands liquor were measured by the FLS920 fluorescence spectrometer which producedIn this paper, a method for discrimination of different bands liquor with strong aroma type based on three-dimensional fluorescence spectrum technology was developed. Firstly, the three-dimensional fluorescence spectra of seven different brands liquor were measured by the FLS920 fluorescence spectrometer which produced by Edinburgh in England. The spectral shows that different bands liquors have similar fluorescence characteristics and it’s difficult to distinguish them only with Fluorescent characteristic parameters. Because of this, the first-order and second-order partial derivatives respect to fluorescence emission wavelength on each of the excitation wavelength were carried out in this paper. Daubechies-7 (db7) orthonormal wavelet with compact support was used to compress the spectral data. The forth approximate coefficients were finally chosen as the new data matrix. Then the new data matrix was analyzed by principal component analysis (PCA) and the principal components were extracted to be used as the inputs of support vector machine (SVM). The K-fold cross validation was applied to optimize the parameters c and γ and the prediction model was constructed in the end. Fourteen samples were selected randomly from each brand that in total of ninety-eight samples were selected as the training set, and the rest forty-two samples were collected as the prediction set. The effect of three different spectral data after processing on the model is compared: original data, the first-order and second-order partial derivatives on the spectral data. The results show that the three-dimensional fluorescence spectra with the pretreatment of second-order partial derivatives coupled with PCA and SVM can make a good performance on the brands identification of strong aroma type liquors, the accuracy of the established model and prediction accuracy were 98.98% and 100%, respectively. This method has the advantage of easy operation, high speed, low cost and provides a good help in the detection and identification of Chinese liquor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1021 (2016)
Temperature Measurement of CH4/Air Premix Flat Flame Based on the Absorption Spectroscopy Technology of UV Tunable Laser
YU Xin, YANG Chao-bo, PENG Jiang-bo, MA Yu-fei, LI Xiao-hui, and ZHANG Ya-li
The physics of combusting flows consists of a complex interaction between chemical reactions, fluid mechanics and radiation. Temperature is one of the most important parameters for the processes. Laser-based imaging techniques are frequently used to assess temperature information from reactive systems without perturbinThe physics of combusting flows consists of a complex interaction between chemical reactions, fluid mechanics and radiation. Temperature is one of the most important parameters for the processes. Laser-based imaging techniques are frequently used to assess temperature information from reactive systems without perturbing the system under study. To verify the feasibility of the temperature measurement of UV tunable absorption spectroscopy technology the methane/air premix flat flame was selected as the target of test because of the combustion stability of this kind of flame. Before the temperature measurement the distribution of OH radical in the premix flat flame under different operating conditions were obtained by using planar laser induced fluorescence (PLIF). At the low equivalence ratio the OH radicals distribute uniformly in the flame for the adequate oxygen in the premix gas. The condition with uniform distribution of OH in the flame was selected for the UV tunable absorption spectroscopy measurement. For the selection of absorption lines of the measurement the spectrum of OH A-X(0,0) band have been simulated by LIFBASE. Considering the slope sensitivity and SNR of the test the transitions P1(2) and Q1(8) were suitable for the temperature measurement of the flame. A dye laser pumped by a frequency doubled Nd:YAG laser was used to generated the UV laser. The dye laser was operated with the mixed dye of DCM and PM580 for high conversion efficiency at 310 nm. To investigate the transitions of Q1(8) and P1(2) of OH A-X(0,0) the laser was tuned from 309.225~309.255 and 308.625~308.655 nm separately with the step of 0.4 pm, 30 pulses were recorded at each step. The laser pulses reflected by the beam splitter were collected by detector A, and the pulses passed the flame were collected by detector B. The signal of these two detectors were recorded by the oscilloscope and acquired by the computer automatically. The line shape of these transitions can be obtained after fitting the experimental data with the Voigt function. The integral ratio between the fitting results of these two lines was calculated. Then temperature of the flame could be deduced by the integral ratio. The temperatures of different positions above the surface of burner and varied heights of the flame center were obtained by measuring the integrated absorption ratio of these two transitions. The test results of this method are compared with the report in reference, in which temperature of the burner with the same structure was measured by other ways. The results of these two tests agree well. It shows that this method has the potential to be a calibration for the two-dimension thermometry in flame such as two-line PLIF..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1027 (2016)
Hydrophilic Surface Modification of Polydimethylsiloxane with UV/Ozone Treatment
L Hong-feng, YAN Wei-ping, LIU Zhi-huan, and LI Jie-chao
The UV/ozone surface treatment was a simple and low cost hydrophilic modification method. In this paper, UV/ozone treatment is utilized to hydrophilize the surface of PDMS and the results are compared. Contact angle is applied to estimate the effect and stability of the modified surfaces. The results show that the contThe UV/ozone surface treatment was a simple and low cost hydrophilic modification method. In this paper, UV/ozone treatment is utilized to hydrophilize the surface of PDMS and the results are compared. Contact angle is applied to estimate the effect and stability of the modified surfaces. The results show that the contact angle is around 60° on the PDMS surface with UV/ozone treatment after 12 hours, and it can maintain the surface hydrophilicity in two weeks under ambient atmosphere. The results of FTIR spectroscopy indicate that many chemical functional groups of PDMS surface have been changed with UV/ozone modification, —CH3 hydrophobic group gradually decrease over time, —OH and Si—OH hydrophilic groups increase obviously, and the characteristic peaks of SiO2 gradually appear. Through SEM/EDS analysis, it has been found that the major constituent of the surface of PDMS is SiO2 after the surface modification. These results demonstrate that the more hydrophilic groups and the glass-like SiOx layer are formed on the PDMS surface modified with UV/ozone, which enhance the surface hydrophilic and minimize the hydrophobic recovery..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1033 (2016)
Study on the Preparation of A New Composite Coagulant: Poly-Ferric-Titanium-Sulfate and Analysis of FTIR Spectrum and UV-Vis Spectrum
CHEN Wei, ZHENG Huai-li, ZHAI Jun, ZHAO Chun, XUE Wen-wen, CAI Na, YANG Qing-qing, and FENG Li
Composite coagulants have drawn a widespread attention recently for its superior coagulation-flocculation performance. Fe and Ti based coagulants, as a kind of inorganic metal water treatment agent, h have received huge attention, but there is little study about the preparation and characterization of composite coagulaComposite coagulants have drawn a widespread attention recently for its superior coagulation-flocculation performance. Fe and Ti based coagulants, as a kind of inorganic metal water treatment agent, h have received huge attention, but there is little study about the preparation and characterization of composite coagulate composite with Ti4+. In this paper we prepared a composite coagulant, in which the Ti (SO4)2 was introduced as coordination complexes, PO3-4 as stabilizer and complexant. Then, the FT-Infra Red spectrum (FT-IR) and ultraviolet/visible absorption spectrum (UV-Vis) were adopted to characterizse the changes of chemical group, species distribution of coagulants in case of varies Ti/Fe, P/Fe and OH/Fe molar ratio. The results shows other than simple mixture of the raw materials, the introduction of Ti4+ and —PO4 group synthesized the chemical group bond as Ti—O, —Fe—P—Fe— and —Ti—P—Ti—, which were beneficial to the degree of polymerization and increased the stability of the product. Furthermore, when the Ti/Fe molar ratio of 1∶8, P/Fe was in the range of 0.2~0.3, the optimal material is suitable for the generation of Fe—P—Ti— chemistry bond and medium polymer as Fe6(OH)6+12, ［Fex(OH)y］2H2PO(6x-2y-1)+4. Whereas, too much addition of Ti4+, PO3-4 and HCO-3 deteriorated the polymer structure, leading to the presentation of precipitate as TiO2, Ti3(PO4)4 and FePO4, which will decrease the coagulation performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1038 (2016)
Denoising Algorithm of UV-Vis Spectroscopy on Water Quality Detection Based on Two-Dimension Restructuring and Dynamic Pane
WU De-cao, WEI Biao, FENG Peng, TANG Bin, and LIU Juan
Based on the successful development of multi-parameter water quality detection system of UV-visible spectroscopy and the actual needs of accuracy, sensitivity, stability and other aspects in the measurement, the research is carried out to create a denoising algorithm of UV-visible spectroscopy on water quality detectioBased on the successful development of multi-parameter water quality detection system of UV-visible spectroscopy and the actual needs of accuracy, sensitivity, stability and other aspects in the measurement, the research is carried out to create a denoising algorithm of UV-visible spectroscopy on water quality detection based on Two-Dimension(2-D) restructuring and dynamic pane. As spectrometry water quality detection systems typically use low-cost industrial grade spectrometer, the CCD photon efficiency and stability are lower than research grade spectrometer, which is built with back-illuminated CCD and internal cooling thermostats. The output spectrum contains significant non-stationary noise, especially in the UV section and IR section. With the traditional denoising method, it is difficult to filter out the noise and retain spectral details at the same time. What’s more, in the case of online or in-situ real-time water quality measurement, the multiple-sample averaging method that commonly used in traditional denoising method may incur additional measurement error due to rapidly changed water sample. The new denoising algorithm proposed by this paper uses the continuous sampling with isochronous gap to expand spectral data into a 2-D matrix composed of spectrum and time axes. After a 2-D wavelet transformation, a variable-width pane which is able to slide horizontally in the coefficient matrix is set. The width of the pane is determined by the change rate of noise variance: the more rapid the rate changes, the narrower the width is. A dynamic denoising threshold is calculated with the wavelet coefficients in the pane and a threshold vector is created with pane sliding. Finally, the spectrum can be denoised by the threshold vector with wavelet shrinkage method. The experimental results show that this denoising algorithm not only removes the spectral non-stationary noise effectively, but also retains the spectral details, which is helpful to improve the accuracy of the instrument. Meanwhile, since time-domain average is not used here, the impact to the denoising performance on fast-changing of water samples is small, which is suitable for the online or in-situ water quality detection environment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1044 (2016)
Study on the Spiral-Torus Herriott Type Cell
WU Fei-long, LI Chuan-liang, SHI Wei-xin, WEI Ji-lin, and DENG Lun-hua
With the rapid development of social economy, the environmental pollution and the ecological destruction are continuously deteriorating while sudden environmental pollution incidents occur frequently. Real-time monitoring harmful gases of the air take advantages of spectroscopic techniques for concentration measurementWith the rapid development of social economy, the environmental pollution and the ecological destruction are continuously deteriorating while sudden environmental pollution incidents occur frequently. Real-time monitoring harmful gases of the air take advantages of spectroscopic techniques for concentration measurement. Multipass optical cells are -widely used in absorption spectrometry technique to improve gas detection sensitivity under the condition of weak absorption. This paper proposes a spiral-torus type multipass optical device base on the structure of Herriott type cell. The optical device consists of multiple torus concave mirrors in a spiral way. Incident light propagates along with radical and axial direction in winding staircase pattern. The faculae on the inner wall present a spiral-type. The entrance and exit apertures are separated due to the spiral trace of optical rays, which increases the accessible adjustment of the apparatus. The effective optical length can be adjusted based on the proportional relationship to the reflective times. This device is characterized with easy adjustment and excellent mechanical performance due to its cylindrical structure. Based on ABCD matrix, the stability of the system was analyzed and the relationship between the number of reflections and the incident angle were discussed. With optical simulation software, we designed a device for separating polarized light, and the characteristics of its rotation was studied..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1051 (2016)
Research on Developping the Colorimetric Correction Method Based on Wide Gamut Spectral Color Dataset
LIU Qiang, WAN Xiao-xia, LI Chan, LIANG Jin-xing, and XIE De-hong
In cross-media digital color imaging workflow, the colorimetric information transform among various digital medias always suffers from large transform errors, due to the difference among the lighting illuminants and the digital devices. Colorimetric correction aims at avoiding the colorimetric transform mismatch and thIn cross-media digital color imaging workflow, the colorimetric information transform among various digital medias always suffers from large transform errors, due to the difference among the lighting illuminants and the digital devices. Colorimetric correction aims at avoiding the colorimetric transform mismatch and thus improving the color transform accuracy comprehensively. Till now, two kinds of colorimetric transform methods have been proposed, which are the chromatic adaptation transform and the regression-based transform. However, since the color gamut of the training samples of such two method are both small, adopting those methods in colorimetric domain always leads to large colorimetric transform errors for the high saturated color regions. In this research, in order to reduce the large correction error in high saturated color regions, a modified colorimetric correction method basing on a wide gamut spectral dataset was proposed. The wide gamut spectral dataset was built by comprehensively collecting and producing typical spectral color samples and could provide optimal training samples for the existing regression based colorimetric correction model, with the help of gamut partition and optimal color purity choosing. By modifying the existing method with such samples, the colorimetric correction performance obviously improved. The experimental result shows that the modified colorimetric correction method performs significantly better than the existing methods and the colorimetric correction errors are successfully reduced by around 15% according to proposed method in form of CIEDE2000 color difference, while as for the high saturated color regions the reduction rate of the colorimetric correction errors approximately grows to 40%. The authors believe that the proposed method will provided effective support for the development of digital color imaging in near future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1056 (2016)
Spectral Mixing Mechanism Analysis of Photosynthetic/Non-Photosynthetic Vegetation and Bared Soil Mixture in the Hunshandake (Otindag) Sandy Land
ZHENG Guo-xiong, LI Xiao-song, ZHANG Kai-xuan, and WANG Jin-ying
Analysis of spectral mixing mechanism of photosynthetic vegetation (PV)/non-photosynthetic vegetation (NPV) and bared soil (BS) mixture would be essential to establish the optimal spectral mixture model and further improve the estimation accuracy of sparse vegetation coverage in Hunshandake (Otindag) sandy land, Inner Analysis of spectral mixing mechanism of photosynthetic vegetation (PV)/non-photosynthetic vegetation (NPV) and bared soil (BS) mixture would be essential to establish the optimal spectral mixture model and further improve the estimation accuracy of sparse vegetation coverage in Hunshandake (Otindag) sandy land, Inner Mongolia of China. Over the past several decades, remote sensing has been widely utilized for estimating the fractional cover of vegetation. However, most efforts have been devoted to the estimation of fractional cover of photosynthetic vegetation (fpv) rather than fractional cover of non-photosynthetic vegetation (fnpv), although the latter is equally important, especially in desertified regions. Among of which, linear spectral mixture analysis was the most popular approach since its simplicity and operability, while the effects of the multiple scattering and the resulting nonlinear mixing problem is seldom concerned. Therefore, taking the Otindag sandy land as the study area, the mixed spectra were acquired over 47 sample plots through utilizing two Hyperion images, and the endmember(PV/NPV and BS) spectral and fraction were acquired through field investigation. Then, linear spectral mixture model(LSMM)and non-linear spectral mixture model (NSMM) including different multiple scattering combinations were adopted to decompose the mixed spectra to determine the optimal spectral mixture model based on the root mean square error (RMSE) of the unmixing and estimation accuracy of fpv and fnpv. The results show: (1) The LSMM consists of PV/NPV and BS endmembers performs fairly well in Hunshandake (Otindag) sandy land, with a RMSE of 0.12 for fpv(R2=0.84) and a RMSE of 0.13 for fnpv (R2=0.66); (2) The performance of NSMMs, which consider different multiple photon scattering effects scenarios, do not improve significantly whether in unmixing RMSE or estimation accuracy of fpv and fnpv. Moreover, non-linear mixing effects among different endmembers has little effect on the estimation accuracy of fpv, but will result in a significant reduction of estimation accuracy on fnpv..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1063 (2016)
Effect of 33 Hz Pulsed Electric Field on Insulin Amyloidosis
LI Qing, WANG Xiang-hui, DU Juan, ZHANG Jie, CHEN Shu-de, and QIAO Deng-jiang
The destabilizing of protein leads to self-aggregation and fibrillar assemblies. In the form of amyloid fibrils or fibril precursors, protein not only lacks the original biological function but also may be harmful to organisms. Stimulated by an intense electric field, the secondary structures of protein can be disturbeThe destabilizing of protein leads to self-aggregation and fibrillar assemblies. In the form of amyloid fibrils or fibril precursors, protein not only lacks the original biological function but also may be harmful to organisms. Stimulated by an intense electric field, the secondary structures of protein can be disturbed and transfer to aggregations or unfolding conformations, which may inhibit the fibrillation process. As a model for disease-associated amyloids, insulin fibrillation is proposed to occur via partial unfolding of a monomeric intermediate. This project is focusing on in-vitro studies employing a 33 Hz pulsed electric field (PEF) to see if there is possible causal connection between insulin fibrillation and PEF exposure. Thioflavin T (ThT)-fluorescence, circular dichroism(CD) and transmission electron microscopy (TEM) techniques were employed regarding the effects of exposure duration and field intensity of the PEF on the fibrillation mechanism of insulin. The results confirm that the PEF exposed insulin molecules may primitively have a slight change in its native structure, causing aggregation. The aggregates in the PEF exposed insulin solution are difficult to dissolve to facilitate the unfolding of insulin molecules. When the molecular conformation converts from α-helical to β-sheet structure, the fibrillation velocity in the PEF exposed insulin is accelerated by the PEF exposure thereby shortening the lifetime of the intermediates. The morphology of mature fibrils changes from long twisted fibrils to shorter and less matured fibrils. All these effects enhance when the exposure duration and electric intensity increase. The investigated evidences suggest that the PEF can inhibit insulin amyloidosis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1069 (2016)
Fingerprint Properties of Cephalosporin Pharmaceutical Wastewater
WU Jing, ZHAO Yu-fei, CAO Jiong-zhun, YANG Lin, LI Zhong-hua, and TANG Jiu-kai
Fluorescence spectrum is unique for each water sample, and is called “aqueous fingerprint”. Aqueous fingerprint could indicate the contamination in water and thus is a new technology for early warning. Cephalosporin is one of the most commonly used antibiotics worldwide yet with environmental hazards. The production ofFluorescence spectrum is unique for each water sample, and is called “aqueous fingerprint”. Aqueous fingerprint could indicate the contamination in water and thus is a new technology for early warning. Cephalosporin is one of the most commonly used antibiotics worldwide yet with environmental hazards. The production of cephalosporin in China is growing every year. Therefore, the study of aqueous fingerprint of cephalosporin pharmaceutical wastewater is significantly important for both monitoring the discharge of pharmaceutical wastewater and protecting the aquatic environment. In this study we investigated the properties of water fingerprint of cephalosporin pharmaceutical wastewater. There existed 6 peaks in the fingerprints. According to the emission wavelength, these peaks could be divided into two groups: the first group included the peaks locating at excitation wavelength/emission wavelength of 230/350, 275/350, 315/350 nm and the second group consisted of the peaks locating at excitation wavelength/emission wavelength of 225/405, 275/410 and 330/420 nm respectively. The highest intensity was found at excitation wavelength/emission wavelength of 230/350 nm. In each group, the fluorescence intensity of the peaks with shorter excitation wavelength is higher. pH could significantly change the position and intensity of the peaks. When pH rose, the peak intensity of first group decreased and that of the second group increased. The intensity decrease is called fluorescence quenching and the intensity increase is called fluorescence sensitizing. The sensitizing and quenching was probably related to the fluorescence organic components with acid and alkaline radical groups in the wastewater. Because if a fluorescent substance contains weak acid or base groups, both the molecular configuration and ionic configurations exist in the solution at the same time. The spatial structure of these configurations are different. This makes the luminescent properties of the configurations different. When pH changes, the ratio of molecular configuration and ionic forms also changes, which causes the change of location and intensity of the fluorescence peaks. Above all, the properties of aqueous fingerprint of cephalosporin pharmaceutical wastewater is distinct and distinguishable. The properties of aqueous fingerprint can be used as a novel tool to identify the appearance of cephalosporin pharmaceutical wastewater..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1075 (2016)
Study on the Wavelength Selection Based on VIP Analysis in Noninvasive Measurement of Blood Components
HE Wen-qin, YAN Wen-juan, HE Guo-quan, YANG Zeng-bao, TAN Yong, LI Gang, and LIN Ling
Selection of independent variable is a hotspot in the field of quantitative spectral analysis. Efficient and easy-to-use method for wavelength selection can not only reduce the computation and improve the accuracy of analysis, but also can reduce dependency on the spectral resolution of instruments and cut cost. WaveleSelection of independent variable is a hotspot in the field of quantitative spectral analysis. Efficient and easy-to-use method for wavelength selection can not only reduce the computation and improve the accuracy of analysis, but also can reduce dependency on the spectral resolution of instruments and cut cost. Wavelength selection is also an important part of the research about noninvasive measurement of blood components by spectrum technology. Dynamic Spectrum theory provides excellent ideas for researchers, but only broadband light source and high-resolution spectrograph were used in correlational studies for a long time. The large number of wavelengths needed for analysis limits the further development of Dynamic Spectrum method. In order to remove redundancy information and make the devices low-cost and integrated, the method of Wavelength selection on the basis of Variable Importance in Projection (VIP) analysis was proposed. Variables with less importance were removed and wavelengths with great explanation power were retained after VIP analysis the number of wavelengths was reduced from 586 to 64. PLS model with 64 wavelengths get a satisfactory predict result that the MREP is 1.82%. The significance test through Bootstrap method validate the selected wavelengths’ explanation power. Moreover, the study pointed out the sensitive wavelengths in Dynamic Spectrum method for the first time. Study also took the first step toward the practical application of Dynamic Spectrum and laid the foundation of low-cost on-line analysis, and it also provided valuable references and new ideas for spectral analysis in other areas..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1080 (2016)
The Design, Synthesis, Characteristics and Photoelectric Properties Research of A Bulky Steric Hindrance 9-Phenyl-Fluorene Functionalized Aniline Intermediate
ZHAO Xiang-hua, LI Xiao-sheng, SHI Nan-nan, YANG Xing-kun, and LI Xiao-yu
In this paper, with sulfuric acid as a catalyst and acetic acid as solution at the temperature of 120 ℃ and refluxing period for 24 hours, a sterically hindered bulky 9,9-diarylfluorene intermediate of ［9-(4-anilino)-9-phenyl-fluorene］ had been successfully designed and synthesized with Friedel-Crafts reaction. The molIn this paper, with sulfuric acid as a catalyst and acetic acid as solution at the temperature of 120 ℃ and refluxing period for 24 hours, a sterically hindered bulky 9,9-diarylfluorene intermediate of ［9-(4-anilino)-9-phenyl-fluorene］ had been successfully designed and synthesized with Friedel-Crafts reaction. The molecular structure of this compound was characterized in detail with nuclear magnetic resonance hydrogen spectrum, mass spectrometry, infrared ray, and so on. Nuclear magnetic resonance hydrogen spectrum and infrared ray spectrum of the compound indicated that the characteristic functional group amino of the compound at 6.55 ppm, 3 481 and 3 385 cm-1, respectively. UV-visible and fluorescence spectra properties of 9-(4-anilino)-9-phenyl-fluorene were characterized and discussed preliminarily, respectively. The research results show that the 9-(4-anilino)-9-phenyl-fluorene with bulky steric hindrance effects has four main absorption peaks with wavelength of 243, 257, 298 and 311 nm in dichloromethane solution, respectively. Moreover, with the excitation wavelength of 308 nm, an emission spectrum curve was obtained with wavelength of 300～500 nm, which has the maximum emission peak of 328 nm with a slim peak at about 405 nm and a long tail to 500 nm. The long tail was probably attributed to the interaction of intermolecular hydrogen bonding from aniline. The appropriate scope of fluorescence emission (300~500 nm) make the compound overlap with the absorption spectra of the classic blue material Bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium (Ⅲ) (FIrpic) (300~500 nm). It is possible to obtain excellent host materials through proper molecular tailoring and prepare well for high performance light-emitting device. In order to further understand the photoelectric properties of the compound, we used acetonitrile as solvent and tetrabutylammonium hexafluorophosphate as electrolyte, and the electrochemical properties of the compound was characterized with cyclic voltammetry measurements.The onset of the reduction and oxidation potential of the compound are -0.759 and 0.898 V, and the corresponding HOMO and LUMO energy levels are -5.38 and -3.72 eV, which wolud be beneficial to holes and electrons injection/transportation and further modified to be excellent host materials. All of these data would provide a useful reference for further fabrication of organic semiconductor luminescent device with high performance..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1085 (2016)
Study on the Interaction between Low Molecular Weight Chitosan-Based Schiff Bases and Bovine Serum Albumin
CAO Juan, HUANG Yan, ZHANG Qi, HUA Yu-jie, HUA Ming-qing, GONG Jian-bo, and ZHU Wei-hua
The novel chitosan-based schiff bases DMABA-CSn were synthesized by the concentration reaction of narrow molecular distribution,low molecular weight chitosan CSn (n represents the degree of polymerization of chitosan, n=6, 8, 11) and 4-Dimethylaminobenzaldehyde (DMABA). The binding reaction between DMABA-CSn and bovineThe novel chitosan-based schiff bases DMABA-CSn were synthesized by the concentration reaction of narrow molecular distribution,low molecular weight chitosan CSn (n represents the degree of polymerization of chitosan, n=6, 8, 11) and 4-Dimethylaminobenzaldehyde (DMABA). The binding reaction between DMABA-CSn and bovine serum albumin (BSA) was studied with fluorescence spectroscopy, synchronous fluorescence spectropy, circular dichroism (CD) and isothermal tiration calorimetric (ITC). The fluoresonance quenching mechanism between DMABA-CSn and BSA was studied with fluorescence spectroscopy. The results indicated that DMABA-CSn (n=6, 8, 11) had the ability to quench the fluorescence from BSA and the quenching mechanism was a static quenching process with complex formation of DMABA-CSn/BSA. The effect of DMABA-CSn on the conformation of BSA was studied with synchronous fluorescence spectroscopy. The results suggested that the conformation of BSA was changed in the microenvironment of DMABA-CSn. Based on the thermodynamic results, the type of binding force was determined between DMABA-CSn and BSA. In addition, the thermodynamics results (ΔH<0, ΔS<0, ΔG<0) with ITC determination indicated that the binding process between DMABA-CSn and BSA was exothermic and spontaneous. What’s more, the main binding force was hydrogen bond and hydrophobic interaction. At the same time, with the increase of polymerization degree of CSn in a certain range of molecular weight, DMABA-CSn can be more easiliy combined with BSA. The research results have provided theoretical reference for the study on pharmacological mechanism of DMABA-CSn (n=6, 8, 11) as potential drugs..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1090 (2016)
Spectral Feature and Mg Number (Fo#) Analysis of Olivine in Sinus Iridium
ZHOU Chao, ZHANG Yuan-zhi, CHEN Sheng-bo, YANG Qian, and HUANG Shuang
The research on the distribution and component of olivine is one of great significance to evaluate the geologic evolution of igneous planetary bodies such as the Moon. In this paper, the Sinus Iidium, as the survey region, was explored by Chang’s serial satellite. Here we present an olivine survey of the Sinus Iridium The research on the distribution and component of olivine is one of great significance to evaluate the geologic evolution of igneous planetary bodies such as the Moon. In this paper, the Sinus Iidium, as the survey region, was explored by Chang’s serial satellite. Here we present an olivine survey of the Sinus Iridium by using Spectral Feature Fitting (SFF) method based on the M3 data. The exposures of olivine were located in the northern crater wall and at the foot of Montes Jura, which were associated with plagioclase and little anorthosite. The stratigraphic units of the located formation were the interior crater slopes and debris ejected from the impact-formed Iridium crater, and the geological age was relatively older. The Mg number of the lunar olivine samples was dependent variables, and the band center of the lunar olivine spectrums were independent, which derived from the fitting analysis using Modified Gaussian Model (MGM). The quantitative inversion models of Mg number (Fo#) of the lunar olivine is established with multiple linear regression analysis. On this basis, the Mg number of the olivine rich point in the Sinus Iridium are calculated with quantitative inversion models of Mg number (Fo#). The result shows that, the Fo# of olivine in the Sinus Iridium are relatively high. The mean value of Fo# is Fo~80.84. As mantle olivine would be expected to be quite Mg-rich, it is suggested that at the vast majority of the olivine detected in the Sinus Iridium come from upper mantle of the Moon..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1095 (2016)
Identification of Oil Type Using Spectral Reflectance Characteristics
LIU Bing-xin, LI Ying, and HAN Liang
The reflectance spectra of 4 common oil types, kerosene (with the thickness of 300, 500 and 1 000 μm), lubricating oil (with the thickness of 300, 1 000, 1 500 μm), light diesel oil (with the thickness of 50, 300, 500 μm) and 180# diesel ( with the thickness of 500 and 2 000 μm) were analyzed by using cluster analysis The reflectance spectra of 4 common oil types, kerosene (with the thickness of 300, 500 and 1 000 μm), lubricating oil (with the thickness of 300, 1 000, 1 500 μm), light diesel oil (with the thickness of 50, 300, 500 μm) and 180# diesel ( with the thickness of 500 and 2 000 μm) were analyzed by using cluster analysis and principal component analysis (PCA), in order to explore a fast, timely method for oil type identification. The results of cluster analysis showed that: when the cluster distance between samples was calculated by Euclidean distance and when the distance L=8.976 samples could be correctly classified, the accuracy was up to100%; it also showed the thickness of oil film affected the clustering effects; the principal component analysis showed that: the PCA scores of wavelet detail coefficients had the best result among the original data, the wavelet approximate coefficients and detail coefficients. The methods of using spectral reflectance data combined with cluster analysis and the principal component analysis based on wavelet detail coefficients to identify the type of water film are feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1100 (2016)
Research on the Spectral Characteristic of Typical Vegetation in Desert-Oasis Crisscross Zone
ZHANG Bo, NIU Ting, FANG Shi-feng, and WU De-yan
Vegetations in desert play key a role in protecting eco-environment, especially in desert-oasis crisscross zone. Vegetations are of great significance in soil conservation and improving the shear resistance of land. Therefore, they can help to prevent soil from wind erosion and keep land from desertification. AnalyzingVegetations in desert play key a role in protecting eco-environment, especially in desert-oasis crisscross zone. Vegetations are of great significance in soil conservation and improving the shear resistance of land. Therefore, they can help to prevent soil from wind erosion and keep land from desertification. Analyzing the spectral data of typical vegetation in desert-oasis crisscross zone by using the hyper spectral technology can be a guidance for remote sensing vegetation classification and serve as the basis for remote vegetation monitoring. In our research, four kinds of typical vegetations have been selected: cotton, tamarix chinensis, Haloxylon ammodendron and Halostachys caspica. The researcher collected series of spectral data of different typical vegetations under different conditions with the help of Field Spec 4 high resolution spectrometer. The collected data was classified, flitted and synthesized with two kinds of transform methods: FDR (First Order Derivative Reflectance) and RLR (Reciprocal Logarithmic Reflectance) transformation. And then three kinds of data were used in further research to analyze the sensitive spectrum band and expression of different vegetation. The result shows that the spectral curve of different vegetations show the same changing trend; different vegetation show different expression in “red edge” with the near infrared band of 780~1 260 nm. The visible light absorption of vegetation is very strong, and the difference of absorption extent causes peaks and troughs. The “red edge” characteristic is unique, which will carry the proper information of certain vegetation, and the result of different kinds of transformation show that FDR can express the red edge characteristic much better than other ways. At last, three ways were used to calculate NDVI, using the original spectral data, transforming spectral data with FDR and transforming spectral data with RLR. Result shows that the NDVI , which calculated by RLR can help to distinguish the type of vegetation with higher accuracy is..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1104 (2016)
Spectroscopic Studies on the Interaction of Human Serum Albumin and Water-Soluble Carboxyl Carbon Nanotubes
WU Shu-rong, LIU Ying, and LIU Shu-fang
The interaction between nanomaterials and biological macromolecules (including protein) is the important basis of biological safety assessments of nanomaterials. In this paper, the fluorescence spectroscopy, synchronous fluorescence spectroscopy and circular dichroism spectroscopy) were used to analyze the interaction The interaction between nanomaterials and biological macromolecules (including protein) is the important basis of biological safety assessments of nanomaterials. In this paper, the fluorescence spectroscopy, synchronous fluorescence spectroscopy and circular dichroism spectroscopy) were used to analyze the interaction between four water-soluble carboxyl carbon nanotubes (long-SWCNTs-COOH, short-SWCNTs-COOH, DWCNTs-COOH and MWCNTs-COOH) and human serum albumin. Results showed that the four water-soluble carboxylated carbon nanotubes could quench the intrinsic fluorescence of human serum albumin at different extents. Under the same concentration, the quenching ability of four carboxylated carbon nanotubes were in the order of DWCNTs-COOH
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1109 (2016)
Experiment Research and Analysis of Spectral Prediction on Soil Leaking Oil Content
YU Lu, LIU Xue-bin, LIU Gui-zhong, FENG Yu-tao, WANG Shuang, and YU Tao
The spectral analysis method was applied experimentally to extract the spectral indices, measure and analyze the spectral characteristics and their difference of the mixture which are composed in soil in Central Shaanxi Plain and the diesel and motor oil respectively, aiming to provide solutions to practical difficultiThe spectral analysis method was applied experimentally to extract the spectral indices, measure and analyze the spectral characteristics and their difference of the mixture which are composed in soil in Central Shaanxi Plain and the diesel and motor oil respectively, aiming to provide solutions to practical difficulties in detecting, analyzing the spectral characteristics and difference between the soil leaking with equal content diesel and motor oil and predicting the leaking content of diesel in the soil. The spectral response curves of the soil leaking with different oil respectively and the soil leaking with diesel with different content were collected. Then the spectral prediction model for the leaking content of diesel in the soil was built based on the reflectance characteristics. The coefficient of the detection (R2) was introduced to evaluate the stability of the built model, and the parameter root mean squared error (RMSE) was introduced to estimate the precision and the predictability of the model built in this work. It is demonstrated that : (1) The reflectance of soil leaking with diesel is less than that of the equal content motor oil. And there is a double absorption trough of the reflectance curve of both soil leaking with diesel and motor oil at 1 740 and 2 328 nm. The spectral absorption indices and absorption depth of the soil leaking with diesel keep less than the equal content motor oil. (2) The built spectral prediction model for the leaking content of diesel in the soil demonstrates good stability with the coefficient of determination at R2=0.854, and performs favorable predictability (Root-Mean-Square Error, RMSE=0.016), which can benefit the effective prediction and quick estimation methods of the leaking content of diesel in the soil, enrich and progress the experimental method and theoretical research work of spectral prediction on soil leaking oil content and promote the application of remote sensing in safety production and environmental protection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1116 (2016)
Study on the Spectrum Research on the Process of Oil Shale Pyrolysis
LAN Xin-zhe, LUO Wan-jiang, SONG Yong-hui, ZHANG Qiu-li, and ZHOU Jun
Spectral analysis is an important and unique advantageous method for the analysis of matter’s structure and composition. Aiming to discuss the change characteristic and evolution mechanism of mineral structure of oil shale, kerogen and sime-coke from oil shale pyrolysis under different temperature, the oil shale sampleSpectral analysis is an important and unique advantageous method for the analysis of matter’s structure and composition. Aiming to discuss the change characteristic and evolution mechanism of mineral structure of oil shale, kerogen and sime-coke from oil shale pyrolysis under different temperature, the oil shale sample was obtained from Yaojie located in Gansu province, and the oil shale after pyrolysis experiments and acid washing were investigated and analyzed in detail withpolarizing microscope, Fourier transform spectroscopy (FTIR), X-Ray diffraction (XRD) and scanning electron microscope (SEM). The result shows that the mainly minerals of oil shale include quartz, clay and pyrite; kerogen is randomly distributed as mainly strip-shaped or blocky in inorganic minerals. The metamorphic degree of kerogen is higher, and rich in aliphatic structures and aromatic structures. Experiments of oil shale pyrolysis(temperature: 300～1 000 ℃, heating rate: 10 ℃·min-1) with temperature increasing, the composition of mineral begins to dissolve, kaolinite turning into metakaolinite with dehydration at 300 ℃, clay minerals such as kaolinite and montmorillonite completely turn into metakaolinite at 650 ℃. The silica-alumina spinel and amorphous SiO2, generated from the decomposition of metakaolinite at 1 000 ℃, and the amorphous SiO2, tends to react with iron mineral to form relative low melting point mixture on the semi-coke surfaces, such as FeO—Al2O3—SiO2. kerogen break down with increasing temperature, the infrared spectra intensity of C—H band of aliphatic and aromatic is reduced, while the intensity of C—C band aromatic is increased, and more carbonaceous residue as gully-shaped that remains in the mineral matrix after pyrolysis. These results are important for both the study of structure evolution of kerogen and minerals on the process of oil shale pyrolysis and will benefit for the subsequent processing and utilization of shale oil resource..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1121 (2016)
Discussion of the Application and Influence Factors of Low-Background Gamma Spectrometry in Distinguishing Sedimentary Rock Types
ZHANG Li-jiao, HUANG Jin-chu, LIN Hong-jian, LAI Wan-chang, LI Dan, WANG Guang-xi, GU Run-qiu, LAI Yu-rou, YAN Rong-hui, and WANG Gang
The contents of radionuclides uranium, thorium and potassium in the sedimentary rocks mainly depend on the contents of clay in the rocks. And the content of clay is the main basis for distinguishing types of sedimentary rock. Therefore, the value of specific activity or content of uranium, thorium and potassium can be The contents of radionuclides uranium, thorium and potassium in the sedimentary rocks mainly depend on the contents of clay in the rocks. And the content of clay is the main basis for distinguishing types of sedimentary rock. Therefore, the value of specific activity or content of uranium, thorium and potassium can be as the quantitative index to distinguish sedimentary rock type. The specific activity or content of radionuclides uranium, thorium and potassium with the method of low-background gamma spectrometry can distinguish the type of rock quickly and accurately. Because of the influence of geometry, mass and moisture content in the sample, the accuracy of distinguishing types of rocks is influenced. This paper makes a theoretical discussion and experimental verification on the influence of mass and moisture content on the results of low-background gamma spectrometry. Results show that there is a linear relationship between (cps) of characteristic peak of all radionuclides and the mass of sample while different energy ranges and lithologies have different linear coefficient and trend fitting degree; The moisture content which is no more than 10%(while collecting samples, the moisture content is no more than 10%) has a little influence on the measurement results( the change values are within the twice standard deviation), so the moisture content which has no significant influence on the accuracy of distinguishing types of sedimentary rock using the method of low-background gamma spectrometry could not be considered. The distinguishing experiment of drilling cuttings samples collected from one oil and gas exploration area in Shanxi Dingbian is done. By the mass correction of the measured data, normalized (cps) ((cps) of per unit mass) of uranium, thorium and potassium channel can only roughly divide the types of sedimentary rocks. Therefore, synthetic distinguishing mode is established with (cps) of combination peak of characteristic peak of uranium, thorium and potassium. The type of rocks is further subdivided, and the distinguishing accuracy is more than 75%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1127 (2016)
Spectral Characteristics and Catalytic Performances of SO2-4/Ce-TiO2 with Visible Light Response
MA Hui-yan, LIU Zheng-jiang, CHENG Lin, YANG Ju-cai, and ZHANG Qian-cheng
Ce doped TiO2 was prepared via sol-gel method. The as-prepared Ce doped TiO2 was impregnated with diluted H2SO4 to obtain a H2SO4-treated Ce doped TiO2. In succession, the characterizations of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), pyridine adsorption-FTIR (Py-FTIR), ultraviolet-visiblCe doped TiO2 was prepared via sol-gel method. The as-prepared Ce doped TiO2 was impregnated with diluted H2SO4 to obtain a H2SO4-treated Ce doped TiO2. In succession, the characterizations of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), pyridine adsorption-FTIR (Py-FTIR), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS) were carried out to analyze the reasons for the improvement of the light response performance. The visible light photocatalytic degradation of Rhodamine B (RhB) in an aqueous solution was used as a probe reaction to evaluate the photocatalytic activity of the obtained samples. According to the XRD analysis, Ce doping created the lattice defects in TiO2 and minimized the particle size, which promoted the transfer of photo-generated electrons and then improved catalyst activity. The bridged bidentate coordination mode of SO2-4 was proposed based on the FTIR spectra. The pyridine FTIR spectra showed that both Lewis and Brnsted acid sites were formed on the sample surface. The characteristic absorption band as Lewis acid was more intense than that of the Brnsted acid, exhibiting the major Lewis acidity. The presence of the Lewis acid sites resulted in the transfer of photogenerated electrons to the Lewis acid center because of the electron deficiency of the Lewis acid sites, which contributed greatly to the transport of the photogenerated electrons, inhibiting the recombination of the photogenerated electron/hole pairs and leading to the enhancement of the photocatalytic activity of samples. From UV-Vis results, Ce-doping introduced an impurity energy level in the band gap, narrowing the TiO2 band gap. The impurity energy level could capture the photogenerated electrons on the conduct band and photogenerated holes on the valence band, reducing the recombination probability of photogenerated carriers and exciting the electrons captured on the impurity energy band by the photons with lower energy, thus expanding the light response range of TiO2. The XPS results indicated that the doped Ce existed as a mixture of Ce3+/Ce4+ states, which facilitated the efficient separation of the photo-generated electrons and holes because of the electron transfer, enhancing the system’s quantum efficiency. The sulfated Ce doped TiO2 catalysts were very active for the visible photocatalytic degradation of RhB. Results showed that the synergetic effects of Ce doping and acid-treatment improved the visible light response for sulfated Ce-doped TiO2, enhancing the visible photocatalytic activity..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1133 (2016)
Study on the Catalytic Kinetic Spectrophotometric Determination of Trace Amounts of Iron(Ⅲ) and Its Reaction Mechanism
LIU Bing-zhi, LUO Zhi-yong, ZHENG Huai-li, and JIANG Lei
A catalytic kinetic spectrophotometric method, which is based on the catalytic effect of Fe(Ⅲ) on the fading reaction between potassium persulfate(K2S2O8) and methyl red(MR) in the solution of 0.30 mol·L-1 hydrochloric acid, for the determination of trace amounts of Fe(Ⅲ) has been investigated. A novel detection sA catalytic kinetic spectrophotometric method, which is based on the catalytic effect of Fe(Ⅲ) on the fading reaction between potassium persulfate(K2S2O8) and methyl red(MR) in the solution of 0.30 mol·L-1 hydrochloric acid, for the determination of trace amounts of Fe(Ⅲ) has been investigated. A novel detection system, Fe(Ⅲ)-HCl-K2S2O8-MR, has been developed. The optimum experimental conditions for the determination of trace amounts of Fe(Ⅲ) were found on the basis of orthogonal test. The kinetics parameters and equation of this fading reaction of MR were studied. Its reaction mechanism was discussed. The results show that there is a good linear relationship between the variation of MR absorbance at the maximum absorption wavelength of 518 nm and the concentration of Fe(Ⅲ) under the optimum experimental conditions: ln(A0/A)=1.334 1+0.001 0, the correlation coefficient is 0.999 1. The kinetic research shows that the reaction order with respect to Fe(Ⅲ) is 1 and the overall fading reaction is a pseudo-first order reaction. The apparent activation energy of the fading reaction of MR is 69.88 kJ·mol-1. Furthermore, the catalytic effects of Fe(Ⅲ) on this fading reaction is confirmed by its reaction mechanism. This novel method for the determination of trace Fe(Ⅲ) has never previously been published so far. Trace amounts of Fe(Ⅲ) can be selectively determined by this catalytic kinetic spectrophotometric method with high precision and accuracy. This method is simple and its reagents used are cheap and available. Its sensitivity is higher than that of conventional spectrophtometry with detection limit of 0.005 mg·L-1. This detection system is stable. This proposed method has been applied to the determination of trace amounts of Fe(Ⅲ) in food and water samples with satisfactory results. Relative standard deviation of the detection results is 1.18%～2.11%. Average recovery rate of the detection results is 98.0%～104.0%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1139 (2016)
Effects of Regions of Interest (ROIs) on Detection Models of Mutton pH Based on Hyperspectral Imaging
DUAN Hong-wei, ZHU Rong-guang, WANG Long, XU Wei-dong, and MA Ben-xue
Selection of Regions of interest (ROIs) and subsequent spectral extraction was a key step of non-destructive detection and analysis based on hyperspectral imaging (HSI). For the rapid and accurate detection of mutton pH, the study on the effects of 2 different ROIs on mutton pH models was carried out in the visible-neaSelection of Regions of interest (ROIs) and subsequent spectral extraction was a key step of non-destructive detection and analysis based on hyperspectral imaging (HSI). For the rapid and accurate detection of mutton pH, the study on the effects of 2 different ROIs on mutton pH models was carried out in the visible-near infrared region of 473～1 000 nm. 2 ROIs methods of Rectangle Regions (RR) and Image Segmentation (IS) were adopted to extract 122 corresponding representative spectra respectively. The influence of different preprocessing methods and ROIs methods on 3 pH models, including stepwise multiple linear regression (SMLR), principal component regression (PCR) and partial least squares regression (PLSR), was compared and analyzed. The results indicated that SMLR and PLSR model performance was optimal in 3 models established with spectral data extracted from Rectangle Regions (RR) and Image Segmentation (IS) respectively. As for the SMLR model, corresponding to the RR ROIs method, the correlation coefficient (Rcal) and root mean square error (RMSEC) of calibration set was 0.85 and 0.085 respectively, and the correlation coefficient (Rp) and root mean square error (RMSEP) of prediction set was 0.82 and 0.097 respectively. As for the PLSR model, corresponding to the IS ROIs method, the correlation coefficient(Rcal) and root mean square error (RMSEC) of calibration set was 0.95 and 0.050 respectively, and the correlation coefficient (Rp) and root mean square error (RMSEP) of prediction set was 0.91 and 0.071 respectively. By comparing the modeling results of spectral data extracted from 2 ROIs methods, the modeling performances of Image Segmentation (IS) were always better than Rectangle Regions (RR) in all the 3 modeling methods. The study shows that it is feasible to apply hyperspectral imaging technology combined with the ROIs method of Image Segmentation (IS) to accurate, fast and non-destructive detection of mutton pH..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1145 (2016)
Study on the Estimation of Nitrogen Content in Wheat and Maize Canopy Based on Band Optimization of Spectral Parameters
LI Dan, LI Fei, HU Yun-cai, Mistele Bodo, and Urs Schmidhalter
Nitrogen fertilizer plays a crucial role in keeping food production in pace with population growth. However, the exceeding application of nitrogen fertilizer causes environmental risks. Timely and accurate quantification of canopy nitrogen content in crops is important for the rational application of nitrogen fertilizeNitrogen fertilizer plays a crucial role in keeping food production in pace with population growth. However, the exceeding application of nitrogen fertilizer causes environmental risks. Timely and accurate quantification of canopy nitrogen content in crops is important for the rational application of nitrogen fertilizer and reduction environmental risks. The current research aimed to remotely estimate canopy nitrogen content in winter wheat and summer maize. Experiments with different N rates for different cultivars of wheat and maize were conducted in southeast Germany and in the North China Plain from 2008 to 2011. The results showed that, compared with traditional red light based spectral parameters, optimized spectral parameters significantly improved the prediction capacity, overcoming saturation problem in deriving canopy nitrogen content of wheat and maize. Band combination of optimized parameters varied with the difference in species and canopy structure of crops. The optimized bands concentrated on 730~760 and 760~800 nm. The best performing spectral parameter was Rλ766/Rλ738-1 for maize, Rλ796/Rλ760-1 for wheat and Rλ876/Rλ730-1 for wheat and maize combination. The validation results further confirmed that the optimized spectral parameters had the lowest predictive error, indicating that optimized spectral indices could estimate canopy nitrogen content of crops. In conclusion, the band optimization of spectral parameters is a promising approach to derive canopy N content in wheat and maize. The findings from this study may be useful for designing improved nitrogen diagnosis systems and for enhancing the applications of satellite-based sensors..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1150 (2016)
Clustering of Hyperspectral Image Based on Spatial-Spectral Chinese Restaurant Process Mixture Model
SHU Yang, LI Jing, HE Shi, TANG Hong, WANG Na, SHEN Li, and DU Hong-yue
The classification of hyperspectral images is one of the most important study fields. The spectral information is used in traditional classification of hyperspectral images, while the spatial correlativity information is ignored. To solve this problem, a novel model called spatial-spectral Chinese restaurant process (sThe classification of hyperspectral images is one of the most important study fields. The spectral information is used in traditional classification of hyperspectral images, while the spatial correlativity information is ignored. To solve this problem, a novel model called spatial-spectral Chinese restaurant process (ssCRP) is proposed to cluster the hyperspectral images, which is an extension of Chinese restaurant process. Both the spatial and spectral information are considered in the modeling and inference of the method. The proposed model clusters the hyperspectral images better than tradional methods and satisfies the requirement of hyperspectral image clustering. Firstly, in order to consider both spatial and spectral information, a new similarity measurement is defined withthe exponential decay function based on the spatial distance and spectral angle among pixels. Then, each pixel is associated with a table based on the table construction by considering the similarity. Finally, each table is allocated with a dish which corresponds to a cluster. Thus, each pixel of the hyperspectral image is allocated with a clustering label. The true hyperspectral image collected by airborne visible infrared imaging spectrometer (AVIRIS) is used to evaluate the performance of our model. Experimental results indicate that the proposed model outperforms traditional K-means and ISODATA. Compared with those of the two methods, the result of the proposed model is more regular with lower salt-and-pepper effect with higher spatial consistency. The classification accuracy of the proposed model reaches to 63.57% and the Kappa coefficient is 0.632 3, much higher than those of K-means and ISODATA. Meanwhile, the edges of the result of our model are well preserved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1158 (2016)
A New Spectral-Spatial Algorithm Method for Hyperspectral Image Target Detection
WANG Cai-ling, WANG Hong-wei, HU Bing-liang, WEN Jia, XU Jun, and LI Xiang-juan
With high-resolution spatial information and continuous spectrum information, hyperspectral remote sensing image -has a unique advantage in the field of target detection. Traditional hyperspectral remote sensing image target detection methods emphasis on using spectral information to determine deterministic algorithm aWith high-resolution spatial information and continuous spectrum information, hyperspectral remote sensing image -has a unique advantage in the field of target detection. Traditional hyperspectral remote sensing image target detection methods emphasis on using spectral information to determine deterministic algorithm and statistical algorithms. Deterministic algorithms find the target by calculating the distance between the target spectrum and detected spectrum however, they are unable to detect sub-pixel target and are easily affected by noise. Statistical methods which calculate background statistical characteristics to detect abnormal point as target. It can detect subpixel target targets and small targets better thanbig size target,. With the spatial resolution increasing, subpixel target detection target has gradually grown to a single pixel and multi-pixel target. At this point, hyperspectral image usually has large homogeneous regions where the neighboring pixels wihin the regions consist of the same type of materials and have a similar spectral characteristics, therefore, the spatial information should be needed to incorporate into the algorithm for targe detection. This paper proposes an algorithm for hyperspectral target detection combined spectrum characteristics and spatial characteristics. The algorithm is based on traditional target detection operator and combined neighborhood clustering statistics. Firstly, the algorithm uses target detection operator to divided hyperspectral image into a potential target region and background region. Then, it calculates the centroid of the potential target area. Finally, as the centroid for neighborhood clustering center to clust data in order to exclud background from potential target area, through iterative calculation to obtain the final results of the target detection. The traditional statistics algorithms defines the total image as background area in order to extract background statistics features, and the algorithm propsed devided the total image into background part and potential target part, which cut off the target interference for background statistics feature extraction. Compared with CEM operators and ACE operators, the algorithm proposed outperforms than traditional operators in big target detection ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1163 (2016)
Study on Form of Ar/Air ICP and A Microwave Diagnostics Based on the Hβ Spectrum Broadening
WEI Xiao-long, XU Hao-jun, LIN Min, SONG Hui-min, and CHEN Mao-cai
The ICP in closed quartz chamber is an effective solution to local stealth of aircraft. The attenuation of the electromagnetic wave is strongly affected by distribution of electron density in incidence direction. In this paper, an experiment that the planar ICP discharged in all-quartz chamber (30.8 cm×30.8 cmThe ICP in closed quartz chamber is an effective solution to local stealth of aircraft. The attenuation of the electromagnetic wave is strongly affected by distribution of electron density in incidence direction. In this paper, an experiment that the planar ICP discharged in all-quartz chamber (30.8 cm×30.8 cm×5.8 cm) was conducted. The E-H mode transition of Ar/Air ICP was observed, and the width and the proportion of ICP area versus the RF power were measured. Such physical phenomena were explained rationally by ICP-source theoretical model. A new microwave diagnostics is presented based on the Hβ spectrum broadening and the characteristics of planar-coil ICP. It is used to diagnose the spatial electron density distribution of Ar/Air in incidence direction. The parameters of electron density distribution function in the incident direction are separately solved by the fitting results of the Hβ stack broadening and microwave interferometer. And the curves of electron density distribution versus RF power are obtained. We obtain a stable ring plasma source with electron density varying from 0.5×1011～3.2×1011 cm-3. The experiment demonstrates that electron density is prominently affected by the RF power and gas species. The peak value of electron density is positioned near the center of ICP. It is shown that the electron density of Ar ICP is higher than the air, but the area of air ICP is larger through comparing the curves of Ar/Air electron density..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1170 (2016)
Study on Self-Absorption Properties in Laser Induced Breakdown Spectroscopy from Copper Sample
XU Song-ning, DUAN When-zhao, NING Ri-bo, LI Qian, AI Zhuo, and JIANG Ran
In this paper, a Nd∶YAG laser with an operating wavelength of 532 nm was employed to generate plasmas of TU0 copper sample on the surface. With grating spectrograph and intensified charge coupled device(ICCD) as spectroscopy analysis detection equipment, self-absorption properties of five atomic lines of Cu(Ⅰ) with wavIn this paper, a Nd∶YAG laser with an operating wavelength of 532 nm was employed to generate plasmas of TU0 copper sample on the surface. With grating spectrograph and intensified charge coupled device(ICCD) as spectroscopy analysis detection equipment, self-absorption properties of five atomic lines of Cu(Ⅰ) with wavelengths of 324.754, 327.396, 510.554, 515.324 and 521.320 nm have been studied and compared with observation time from 211 to 300 μs after the trigger and laser energy from 30 to 100 mJ. The result indicates that the extents of self-absorption of atomic lines decrease with increasing observation time and after a period of time of 5 to 20 μs the self-absorption cannot be observed; with the increase of laser energy ranging from 50 to 100 mJ, the self absorption shows an increase of extents and duration. Meanwhile the self-absorption properties differ due to different energy-level states of atomic spectrum line transition. Changes of self-absorption extents with observation time and energy and of self-absorption duration with energy exhibit similar characteristics for the two groups of lines range from 324.754 to 327.396 nm and 515.324 to 521.320 nm, respectively, with the same atomic configuration. Moreover, the extents of self-absorption at spectral lines with large angular momentum (324.754 nm, 1/2-3/2 and 521.320 nm, 3/2-5/2) are more sensitive to change of the laser energy with a higher value of extent change and a longer duration. In comparison, the self-absorption of spectral line 510.554 nm (3d104p-3d94s2) has low extent and short duration when laser energy is below 80 mJ, and the extent increases and the duration becomes longer for the energy range from 80 to 100 mJ..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1175 (2016)
Study on the Enhancement Intensity of Cd in Rice with Microwave-Assisted Laser-Induced Breakdown Spectroscopy
HU Hui-qin, XU Xue-hong, HUANG Lin, YAO Ming-yin, CHEN Tian-bing, LIU Mu-hua, and WANG Cai-hong
As food safety problem has become the focus of attention all over the world, green detection methods of the contaminants in food is in accordance with the sustainable development of environment. Heavy metal pollutant Cd element in rice was used as the object of study in this work, laser induced breakdown spectroscopy (As food safety problem has become the focus of attention all over the world, green detection methods of the contaminants in food is in accordance with the sustainable development of environment. Heavy metal pollutant Cd element in rice was used as the object of study in this work, laser induced breakdown spectroscopy (LIBS) and microwave assisted laser induced breakdown spectroscopy (MA-LIBS) were utilized to detect the blank and laboratory polluted rice samples respectively. The characteristic line of Cd Ⅰ 228.802 nm was employed as analytical line to discuss the enhancement effect of plasmas emission intensity for the analytical line of target element. Meanwhile, the actual concentration of Cd in rice was measured by anodic stripping voltammetry. The result displayed that LIBS can just detect the plasmas signals of the sample which contained 13.69 μg·g-1 cadmium for the laboratory polluted rice samples which concentration range from 2.16 to 13.69 μg·g-1, however, in the same experimental conditions, MA-LIBS can detect the plasmas signals of Cd in all of the contaminated rice samples successfully, and compared with LIBS, the plasmas emission intensity of Cd element was enhanced from 9 to 27 times. The results showed that the plasmas emission intensity of Cd element in rice can be enhanced effectively by MA-LIBS, and the detection sensitivity can be effectively improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1180 (2016)
Study on the Spatial Distribution of Laser Induced Plasma Emission Underwater with Different Laser Energies
XUE Bo-yang, TIAN Ye, SONG Jiao-jian, LU Yuan, and ZHENG Rong-er
Laser-induced breakdown spectroscopy (LIBS), as a promising in-situ underwater detection technology, has received extensive attention in the field of ocean exploration. Improving the remote sensing ability of LIBS is crucial in bringing this technology into practical applications, hence higher laser energies, i.e. overLaser-induced breakdown spectroscopy (LIBS), as a promising in-situ underwater detection technology, has received extensive attention in the field of ocean exploration. Improving the remote sensing ability of LIBS is crucial in bringing this technology into practical applications, hence higher laser energies, i.e. over threshold, are required. To characterize the plasma induced with super threshold energies and have a better understanding of resulted moving breakdown process, some extensive investigations into KCl water solution have been carried out with spectra-image jointed analysis. The spatial span and the brightest spot position of plasma radiation, with different laser energies from 1 to 20 mJ, were determined from the recorded plasma images. It was found that the plasma stretched from 0.49 to1.83 mm, as the laser pulse energy increased from 1 to 20 mJ, with a center position shift of 0.79 mm towards the incident laser beam. The obvious power dependence has also been observed from the obtained spatial resolved atomic spectra. Although the axial distributions at different energies were similar, both the position and the intensity of potassium atomic emission maximum varied. The optimal laser energy was determined to be 5 mJ with the emission intensity maximum higher than that at any other investigated energies. The obtained results suggested that the power dependence of atomic emission should be taken into account on increasing laser energy to meet the needs of stand-off LIBS applications. The FWHM and signal to background ratio of K Ⅰ 769.90 nm under different laser energies have also been investigated..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1186 (2016)
Determination of Main Active Components and Metal Elements of Hainan Alpinia Katsumadai by Spectral Analysis
WU Xiu-li, ZHAO Zhi-zhong, WU Dan, CHEN Guang-ying, LIU Hong, HE Meng-xiong, DING Guo-hua, and HE Wen-ying
Fourier transform infrared spectroscopy (FT-IR), UV spectroscopy and fluorescence spectroscopy combined with inductively coupled plasma mass spectrometry (ICP-MS) were employed to analyze Alpinia Katsumadai harvested from Hainan Baisha and Bawangling. The results from FT-IR indicated that the emergence of several charaFourier transform infrared spectroscopy (FT-IR), UV spectroscopy and fluorescence spectroscopy combined with inductively coupled plasma mass spectrometry (ICP-MS) were employed to analyze Alpinia Katsumadai harvested from Hainan Baisha and Bawangling. The results from FT-IR indicated that the emergence of several characteristic absorption peaks around 1 051, 1 390, 2 976 and 3 300 cm-1 belong to flavonoids. In light of second derivative spectra, two similar peaks around 2 977.72 and 2 899.94 cm-1 and evident differences peaks around 1 922.36 and 1 650.87 cm-1 were observed, which was obvious to identify and distinguish Hainan Alpinia Katsumadai from different geographical regions. The method of UV spectroscopy were used to determine the different characteristic spectra of Alpinia Katsumadai harvested from Hainan Baisha and Bawangling. An UV-quantitative analysis method for alpinetin and cardamonin in Alpinia Katsumadai was established according to the relevant absorption principle. The results from fluorescence experiments revealed that both ethanol extracts of Alpinia katsumadai Hayata harvestd from Baisha and Bawangling have the similar fluorescence emission spectra and excitation spectra. The difference of fluorescence intensity once again demonstrated the concentration of ethanol extracts of Alpinia katsumadai Hayata harvestd from Baisha was bigger than that of Bawangling. The good relative recovery was in the range of 84.28%～117.41% with the RSDs (n=3) of 0.42%～0.29%. The content of alpinetin and cardamomin in Alpinia katsumadai from various habitats are 4.23% and 3.83% for Baisha, 3.72% and 3.34% for Baiwangling, respectively. Seventeen kinds of metal elements including K, Ca, Mg, Na, Al, Fe, Mn, Cu, Zn et al were determined by using microwave digestion-ICP-MS. Therefore, FT-IR combined with second derivative spectra was an express and comprehensive to analyze and evaluate the subtle difference among different habitats. It was also indicated that the method of UV-absorption spectroscopy was simple and reliable for identifing Alpinia katsumadai from differern geographical regions and cultivation batches, and determining qualitatively and quantitatively their main active components. The determination results of metal elements according to ICP-MS experiments will provide a theoretical foundation for the further development and utilization Alpinia katsumadai and enhancing the food danger consciousness..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1191 (2016)
Quantitative Analysis of Mn in Soil Based on LIBS with Multivariate Nonlinear Method
WANG Ping, and LI Dui-yuan
Manganese (Mn) is one of the indispensable micronutrients for plants. The concentration of Mn in soil was determined with laser-induced breakdown spectroscopy (LIBS) in this paper. Forty-six soil samples were used to obtain the spectrum data of LIBS. The characteristic line of 403.1 nm was selected as the analytical liManganese (Mn) is one of the indispensable micronutrients for plants. The concentration of Mn in soil was determined with laser-induced breakdown spectroscopy (LIBS) in this paper. Forty-six soil samples were used to obtain the spectrum data of LIBS. The characteristic line of 403.1 nm was selected as the analytical line of Mn. The calibration curve of the net intensity of Mn line at 403.1 nm versus the corresponding concentration was constructed withthe correlation coefficient 0.78. The results showed that, due to the complex chemical compositions of soil samples, the calibration method influenced by the matrix effect seriously. It should utilize more information of LIBS spectra to construct the multivariate nonlinear calibration method, which can reduce the matrix effect and improve the measurement accuracy of LIBS. With multivariate nonlinear calibration method, the interference effect of C and Fe elements on the concentration of Mn was considered. Compared with calibration method, the correlation coefficient of the prediction concentration of LIBS with reference concentration was 0.97, and the relative measured error was in the range 3.2%~10.3%,Therefore, the measurement accuracy of LIBS was increased. The experimental results demonstrate that LIBS combined with multivariate nonlinear calibration method can be used to quantitative analysis of Mn in soil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1197 (2016)
Determination of Platinum Group Elements in City Roadside Dusts by ICP-MS
ZOU Xiao-wen, GAO Bo, ZHOU Huai-dong, HAO Hong, and XU Dong-yu
Platinum group elements (PGEs) can be naturally found only at very low concentration in the earth crust. However, the increasing usage of PGEs in vehicle exhaust catalysts, and some other applications cause their anthropogenic emission and spread in the environment. Currently, the accumulation of PGEs in the environmenPlatinum group elements (PGEs) can be naturally found only at very low concentration in the earth crust. However, the increasing usage of PGEs in vehicle exhaust catalysts, and some other applications cause their anthropogenic emission and spread in the environment. Currently, the accumulation of PGEs in the environment has increased over the time. Catalytic converters of modern vehicles are considered to be the main sources of PGE pollution. In order to survey PGEs contamination at residential districts in the urban areas of Beijing City, roadside dust samples were collected. The roadside dust samples were digested with aqua regia and separated and purified with cation exchange resin (Dowex AG50W-X8), and then the resulting solutions were analyzed with inductively coupled plasma mass spectrometry (ICP-MS). PGEs pollution degree in dusts was analyzed using Geoaccumulation Index. The results showed that the concentrations of Pd, Pt and Rh in roadside dusts ranged from 14.20～161.80 ng·g-1 (50.76 ng·g-1), 9.39～70.80 ng·g-1(23.82 ng·g-1), 3.18～17.05 ng·g-1(7.54 ng·g-1), respectively. It indicated that concentrations of PGEs in dusts of residential areas were obviously higher than those values in Beijing soil background. The results of Geoaccumulation Index assessment indicated that the roadside dusts in residential areas were obviously polluted by the PGEs in Beijing city. The order of average pollution level of the PGEs is: Pd＞Pt＞Rh..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1202 (2016)
Study on the Mechanism to Ease the Leaching Effect of Nutrient in the Multi-Contaminated Loess Washing Process with the Addition of Anion Adsorbent(Ⅱ)
FAN Chun-hui, GAO Ya-lin, ZHANG Ying-chao, and CHANG Min
The soil washing technology is commonly used to remediate contaminated soils because of its advantages of low cost, ease handling and environmental-friendly. However, it should be noticed that the nutrient might leach simultaneously from soil in the washing process, and the technical solution of the issue will greatly The soil washing technology is commonly used to remediate contaminated soils because of its advantages of low cost, ease handling and environmental-friendly. However, it should be noticed that the nutrient might leach simultaneously from soil in the washing process, and the technical solution of the issue will greatly accelerate the application process of washing technology in site remediation. This paper aims to reveal the regulating mechanism of synthesized anion adsorbent from straw on nutrient leaching potential through approaches of adsorption equilibrium models (isotherms and kinetics) and spectral analysis instruments (SEM and FTIR). The results showed: the Langmuir isotherm and pseudo second order kinetic equation fit better the adsorption behavior of nitrate and phosphate. The maximum adsorption capacity (qm), calculated with Langmuir isotherm, are 7.507 5 and 4.194 6 mg·g-1, respectively, and the reaction belongs to the monolayer and favorable adsorption with chemical adsorption the rate-determining step. The activation energy of adsorption for nitrate and phosphate at 298 K are 42.25 and 39.38 kJ·mol-1, respectively, and the reaction is spontaneous and endothermic. The purified water and KOH solution are effective for the regeneration of anion adsorbent, the desorption effect is better for the assistance of ultrasonic sound and longer desorption time. The surface of anion adsorbent after adsorption is covered with particles, while less spray-like component appears after desorption with purified water. The movement of vibration peaks in FTIR spectra indicates the effect of electrostatic interaction in the reaction. The adsorption of nitrate and phosphate on anion adsorbent involves simultaneously the effects of physical and chemical adsorption..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1205 (2016)
Improving Analytical Methods by Uncertainty Evaluation with the Case of Determination of Aluminum in Starch Products by ICP-MS
GAO Rui-feng, GAO Meng-chao, LING Rui, and ZHANG Ning
The measurement uncertainty is a non-negative parameter associated with the result of a measurement that characterizes the dispersion of the quantity values that could reasonably be attributed to the measurand. In the present study measurement uncertainty is estimated using the GUM (ISO/IEC Guide 98: 1993 Guide to the The measurement uncertainty is a non-negative parameter associated with the result of a measurement that characterizes the dispersion of the quantity values that could reasonably be attributed to the measurand. In the present study measurement uncertainty is estimated using the GUM (ISO/IEC Guide 98: 1993 Guide to the expression of uncertainty in measurement) bottom-up approach. The steps were followed: specifying the measurand; identifying all the associated sources of uncertainty; quantifying the uncertainty components; combining the uncertainty components; determining the extended combined standard uncertainty; reviewing the estimates and reporting the measurement uncertainty. In this process, the major uncertainty components with greater impact were identified; try to eliminate or to reduce the impact of these components can improve measurement methods. Examples were the determination of aluminum in starch and bread crumbs by inductively coupled plasma-mass spectrometry (ICP-MS). The uncertainties of aluminum contents were from measurement repeatability, variability of calibration curve, standard stock solution, dilution, solution volume and sample weighing. The data indicated that the major contributions to the uncertainty budget originating from urel(cAl)1 (the relative standard uncertainty of aluminum content derived from linear least squares calibration), urel(cAl)3 (the relative standard uncertainty of aluminum content derived from the dilution of the standard stock solutions) and urel(rep) (the relative standard uncertainty derived from the repeatability). Based on the analysis of the main individual contributions of each uncertainty source to the total uncertainty value, several modifications were proposed. Firstly helium collision mode was replaced by no gas mode to improve the sensitivity of mass spectrometry. Secondly the number of measurements was increased. Thirdly let the mean of data points in the calibration closer the measurand. Finally the relative error smaller gauges were used. After these modifications, urel(cAl)1, urel(cAl)3 and urel(rep) were from (0.035 8, 0.013 2, 0.008 5) down to (0.006 0, 0.010 5, 0.003 3), respectively; the combined relative standard uncertainty of aluminum was from 0.039 down to 0.013; the expanded uncertainty from 1.8 down to 0.4 mg·kg-1(coverage factor k=2). The improvement effect was significant..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1211 (2016)
Determination of Bi in Soils and Sediments by Atomic Fluorescence Spectrometry
LIN Hai-lan, LI Zhi-huang, ZHU Ri-long, SONG Bing-bing, LIU Pei, BI Jun-ping, and LUO Yue-ping
A method for determination of the contents of Bi in soils and sediments by atomic fluorescence spectrophotometry (AFS) was established by using aqua regia as the dissolved medium. In this paper, the instrument parameters, load flow and reducing agent concentration were optimized. Compared with microwave digestion and eA method for determination of the contents of Bi in soils and sediments by atomic fluorescence spectrophotometry (AFS) was established by using aqua regia as the dissolved medium. In this paper, the instrument parameters, load flow and reducing agent concentration were optimized. Compared with microwave digestion and electric heating plate digestion, water bath digestion demonstrated the better digestion efficiency and was most commonly used. Under the optimal experimental conditions, the detection limit (LOD) was 0.01 mg·kg-1 (sample quantity 0.500 0 g, sample volume 50 mL), and the limit of quantitation (LOQ) was 0.04 mg·kg-1. The results were in good agreement with the centified value, and the relative error was -4.7%~-2.0%. For determination of soil and sediment actual samples, the relative standard deviation (RSD) were 2.5%~3.4% and 3.1%~3.4%, respectively, and the recoveries of the method respectively ranged from 97.6%~102% and 99.5%~104%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1217 (2016)
Detection of Sulfur Dioxide in Preserved Fruits with High Resolution Continuum Source Atomic Absorption Spectrometry Assisted with Distillation
ZU Wen-chuan, WANG Yu, ZHANG Yu-xiang, LI Bing-ning, LIU Cong, and REN Min
The CS diatomic molecules can be transformed from sulfur in fuel-rich air acetylene flame. The absorbance of CS can be detected with atomic absorption spectrometry as the CS line profile is similar to the atomic absorption. A novel method was established to detect the sulfur dioxide in preserved fruits with high resoluThe CS diatomic molecules can be transformed from sulfur in fuel-rich air acetylene flame. The absorbance of CS can be detected with atomic absorption spectrometry as the CS line profile is similar to the atomic absorption. A novel method was established to detect the sulfur dioxide in preserved fruits with high resolution continuum source atomic absorption spectrometry. The sulfate ions can be transformed from the SO2 in preserved fruits after the experience of acidity, distillation and oxidation with H2O2.The instrumental parameters influencing on the sensitivity of SO2 determination were optimized, including the velocity of acetylene, the flame height, etc. And the interference of different S species, such as SO2-4, S2O2-3, etc on the SO2 recovery was observed. In the optimal conditions, the limit of detection under the wavelength of 257.961 nm was 52.4 mg·kg-1, and the relative standard deviation was below 10%. The average spiked recoveries between 85.7% and 115.7% were achieved when this method was used for real preserved fruits samples analysis. It’s proved that this method has the merits of high accuracy rapid analysis and low interference, and the application areas of atomic absorption spectrometry were extended..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1221 (2016)
Study of Ultrasonic Nebulizer Assisted Spark Induced Breakdown Spectroscopy as a Metal Elements Analysis Method for Aqueous Sample
ZHONG Shi-lei, QI Fu-jun, SUN Xin, CHENG Kai, MA Jun-yan, and SUN Yu-xiang
In order to develop a high sensitive and low cost metal elements analysis method for aqueous sample, an ultrasonic nebulizer assisted spark induced breakdown spectroscopy (UN-SIBS) system is established, where an ultrasonic nebulizer is employed to transform the bulk liquid sample into aerosol composed by intensive droIn order to develop a high sensitive and low cost metal elements analysis method for aqueous sample, an ultrasonic nebulizer assisted spark induced breakdown spectroscopy (UN-SIBS) system is established, where an ultrasonic nebulizer is employed to transform the bulk liquid sample into aerosol composed by intensive droplets. And a high tension coil and a couple of electrodes are combined to induce the plasma. The spectra emitted are collected to analysis the metal elements in the aqueous samples. Based on the experimental system, the features of emission spectra are studied. The electron density and electron temperature are calculated to understand the physics characteristic of the plasma in UN-SIBS experiments. Samples of different concentration of lead are analyzed by UN-SIBS method to make clear of the relationship between concentration and the peak intensity of the heavy metal element Pb. Besides, the atomic line of lead at 261.37 nm detected by the sample with the concentration of 2.07 ppt could be easily distinguished which is better than the LOD reported in references. The aqueous samples with calcium, as a lower activity metal element, are also studied. At last, the possible mechanism is discussed according to the experimental results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1225 (2016)
TOF-SIMS Study of Mannitol and Cordycepin in Cordyceps Sinensis
LI Zhan-ping, Noriaki Sanada, and SUN Su-qin
Cordyceps sinensis is a well-known traditional Chinese medicine; it is also called DongChongXiaCao (winter worm summer grass) in Chinese. Mannitol and cordycepin, the most important two pharmacological active components of cordyceps sinensis, were studied with TOF-SIMS. This Study was focused on the chemical informatioCordyceps sinensis is a well-known traditional Chinese medicine; it is also called DongChongXiaCao (winter worm summer grass) in Chinese. Mannitol and cordycepin, the most important two pharmacological active components of cordyceps sinensis, were studied with TOF-SIMS. This Study was focused on the chemical information including 251 amu mass peak. Based on high mass resolution of TOF-SIMS analysis, the fragment ions of 251 and 252 amu detected in Cordyceps sinensis may not be the molecular ion M+ and/or［M+H］+ of cordycepin, which ispossiblely the root cause of the argument in the study of cordycepin in published papers .It could be a basis for further study of cordycepin components of cordyceps sinensis in the future. The 181amu mass peak of minus ion in mannitol was also studied in detail and was certified to be a reliable evidence of mannitol. This research shows that TOF-SIMS has been proven as an effective method in the study of cordyceps sinensis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1230 (2016)
Research on the Background Subtraction Method for X-Ray Fluorescence Spectrum with X-Ray Tube Excitation
GUO Cheng, LAI Wan-chang, HU Yuan, HUANG Jin-chu, ZHAI Juan, CHENG Feng, WANG Guang-xi, ZENG Guo-qiang, and ZHANG Qing-xian
X-ray tube is the most commonly used equipment in X-ray fluorescence spectrum analysis as excitation source whose primary spectrum has become a major source of the background of X-ray fluorescence spectrum. Background subtraction should go before further analysis of this spectrum. The accuracy of the estimation of the X-ray tube is the most commonly used equipment in X-ray fluorescence spectrum analysis as excitation source whose primary spectrum has become a major source of the background of X-ray fluorescence spectrum. Background subtraction should go before further analysis of this spectrum. The accuracy of the estimation of the background directly affect the results of subsequent processing steps. In this paper, the tube excitation component of X fluorescence spectrum is analyzed with an estimation method of background intensity against their background characteristics, and structuring theoretical spectral lines based on the measured spectral lines in order to evaluate the effect of spectral processing algorithms. The method utilizes the measured X-ray fluorescence spectrum which does not contain the characteristic peak of the spectrum, In order to estimate the composition of the original spectrum of the X-ray tube. It uses the spectrum that contains the continuous background for interpolating the entire measured spectrum, thereby avoiding overlapping the spectral characteristic peaks or improperly estimating full width at half maximum. This paper compared SNIP, Fourier transform method and the background subtraction method using the measured spectral lines. Using this method to estimate the background is closer to the theoretical background. The results showe that the method for X-ray fluorescence spectrum by X-ray tube excitation is accurate in this article, this method can be used to deduct continuous background, and good applied effectiveness has been achieved in the background subtraction of the actually measured X-ray fluorescence spectrometry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1235 (2016)
Rapid Determination of Cu and Zn in PM2.5 with Wavelength Dispersive X-Ray Fluorescence Spectrometry
WANG Guang-xi, LI Dan, GE Liang-quan, CHEN Cheng, LAI Wan-chang, ZHAI Juan, LAN Yong, HU Jie, and LONG Fei
This paper proposes the analyzing method of adopting wavelength dispersive X-ray fluorescence spectrometry to measure the content of Cu and Zn in PM2.5. PTFE membrane is used to prepare standard samples and atmospheric particulate samples; a research into sample cup’s structure, using polypropylene film of 6.7 μm to heThis paper proposes the analyzing method of adopting wavelength dispersive X-ray fluorescence spectrometry to measure the content of Cu and Zn in PM2.5. PTFE membrane is used to prepare standard samples and atmospheric particulate samples; a research into sample cup’s structure, using polypropylene film of 6.7 μm to help to improved sample cup to package atmospheric particulate samples. The improved sample cup is used to measure the content of Cu and Zn in atmospheric particulate, which can obviously reduce background, improve peak/background ratio and decrease detection limit to target element; discussion is made on the measurement condition of Cu and Zn in PM2.5: taking Kα line as analysis line of Cu and Zn, selecting PX10 as analyzer crystal, using 300 μm pitch collimator, adopting scintillation detector for the Kα of Zn, applying the integrating of flow-gas proportional counter and closed-end proportional counter to the Kα of Cu, setting 50 kV, 50 mA as operating voltage and current. The prepared Cu and Zn standard sample is used to set up working curve, the results show that their linear correlations are better, accuracy are higher, relative standard deviations of Cu and Zn are 2.43% and 2.00%(n=8), detection limit are 0.028 and 0.021 μg·cm-2respectively, and analysis of the single sample only need 60 s. To sum up, this method can quickly and accurately analyze the content of Cu and Zn in PM2.5, and provide scientific basis for study the element content characteristics and source apportionment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1240 (2016)
Study on Stellar Spectral Outliers Mining Based on Fuzzy Large Margin and Minimum Ball Classification Model
LIU Zhong-bao, and ZHAO Wen-juan
It’s one of the main goals in universe exploration to find unknown and special celestial bodies. The spectra outlier data is analyzed based on the traditional classification approaches, which is a general method of special celestial body exploration. But it’s depressed that many traditional classification approaches arIt’s one of the main goals in universe exploration to find unknown and special celestial bodies. The spectra outlier data is analyzed based on the traditional classification approaches, which is a general method of special celestial body exploration. But it’s depressed that many traditional classification approaches are insensitive to the outlier data, which even influence the classification efficiencies, therefore, these methods can’t accomplish the task of special celestial body exploration. In view of this, Fuzzy Large Margin and Minimum Ball Classification Model (FLM-MBC) is proposed in this paper. In FLM-MBC, part of general data and outlier data are trained to construct the minimum ball model and the fuzzy technique is introduced to reduce the noise influence to classification. Comparative experiments with C-SVM, KNN, and SVDD on the SDSS spectral datasets verify the effectiveness of the proposed FLM-MBC..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1245 (2016)
Detection System for High-Resolution and Broadband-2D Spectrogram
WU Rui, ZHANG Yin-xin, HUANG Zhan-hua, YANG Huai-dong, and JIN Guo-fan
In order to meet the demand of detecting the high-resolution and broadband-2D spectrogram for echelle-prism cross-dispersion, the design method is given, and the 2D spectrogram detection system with high-resolution and low noise is designed by analyzing the relation between the detector and the optical system and proviIn order to meet the demand of detecting the high-resolution and broadband-2D spectrogram for echelle-prism cross-dispersion, the design method is given, and the 2D spectrogram detection system with high-resolution and low noise is designed by analyzing the relation between the detector and the optical system and proving designing method of detecting the area spectrogram. The system includes a main control unit, a detector driving unit, a signal processing unit, a data storage unit and a data transmission unit, etc. With Hamamatsu’s S10141-1109S CCD as the detector, the detection system features high sensitivity, broadband spectrogram, high signal to noise ratio. Combined with the echelle-prism cross-dispersion optical path to perform experiments, the results show that, the detection system can acquire high-resolution 2D spectrogram image in the range of 200 to 600 nm, the monochromatic image at 253.652 nm of Hg lamp covers 5 pixels, and the resolvable wavelength reaches 6.3 pm..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1249 (2016)
Laser Ablation of 6H-SiC Single Crystals and Spectral Characterization
YU Wan-cheng, HU Xiao-bo, CUI Ying-xin, CHEN Xiu-fang, and XU Xian-gang
Laser micromachining has proven to be a useful tool for precision processing of semiconductors. For Silicon Carbide (SiC) single crystals, ablation with ultraviolet wavelength laser could lead to the maximum absorption efficiency of incident energy. In this paper, laser ablations were performed on 6H-SiC single crystalLaser micromachining has proven to be a useful tool for precision processing of semiconductors. For Silicon Carbide (SiC) single crystals, ablation with ultraviolet wavelength laser could lead to the maximum absorption efficiency of incident energy. In this paper, laser ablations were performed on 6H-SiC single crystals through a 355 nm solid state laser. Different confining media were also employed to find the optimal processing condition. The surface of SiC after laser ablation was characterized by Raman spectroscopy. Amorphous silicon and nanocrystalline graphite were found to be the main compositions left. For SiC wafers ablation in air, the amorphous silicon exhibited mainly around rather than inside the ablated crater. However, the amorphous silicon showed opposite spatial distribution features for samples processing under liquid. Through analysis of the compositions left on the ablated surface, the ablation mechanism was investigated from another point of view. For liquid confined laser processing,previous studies mainly concentrate on the thickness and viscosity of the liquids, little information has been done on the reducibility of liquids. To investigate the influence of liquid reducibility, the surface morphology and oxygen content of ablation under different confining media were checked by confocal laser scanning microscopy and energy dispersive spectroscopy. Results showed that the reducibility of confining liquid also played a vital role in the ablation process under liquid. Utilizing liquids with deoxidizing ability as confining media will result in a remarkable reduction of surface oxygen content and a more regular morphology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1255 (2016)
In Situ Raman Spectrum Peak Test of Monocrystalline Silicon Wafer under Quantitative Uniaxial Pressure
XIE Chao, DU Jian-guo, LIU Lei, YI Li, LIU Hong, CHEN Zhi, and LI Jing
The relationship between total uniaxial stress (F/N) and strain (ε/μm/m) of wolfram carbide (WC) base in diamond anvil cell was measured: F=3.395ε+12.212 (R2=0.999 9), and a device was developed which can be used to test the spectral characteristics of the sample in situ under quantitative uniaxial pressure. The Raman The relationship between total uniaxial stress (F/N) and strain (ε/μm/m) of wolfram carbide (WC) base in diamond anvil cell was measured: F=3.395ε+12.212 (R2=0.999 9), and a device was developed which can be used to test the spectral characteristics of the sample in situ under quantitative uniaxial pressure. The Raman spectrum peak of monocrystalline silicon wafer was tested by using this device under a uniaxial pressure up to 2 548.664 MPa. The test result shows that, when the pressure is perpendicular to ［100］ crystal plane of the monocrystalline silicon sample, the 519.12 cm-1 peak shifts towards high frequency linearly with increasing pressure, and the linear relationship between shift amount of Raman spectrum peak frequency (Δω/cm-1) and pressure (σ/MPa) is: σ=365.80Δω+10.19, wherein the constant may reflect the presence of residual stress in the sample to some extent, and some difference between monomial coefficient and the result of theoretical calculations may be due to sample stress orientation in this experiment.The constant in the Δω-σ linear relationship reflects experimental errors and the value of residual inner stress to some extent..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1261 (2016)
Comparison of Spectral and Molecular Analyses for Classification of Long Term Stored Wheat Samples
Fatih Kahrman, and Cem mer Egesel
This study aimed to determine whether NIR spectroscopy and protein band analysis can differentiate the grain samples of 15 wheat genotypes stored for different periods: Group Ⅰ (91 weeks), Group Ⅱ (143 weeks), Group Ⅲ (194 weeks), and Group Ⅳ (246 weeks). Samples were harvested from previously-conducted field trials, aThis study aimed to determine whether NIR spectroscopy and protein band analysis can differentiate the grain samples of 15 wheat genotypes stored for different periods: Group Ⅰ (91 weeks), Group Ⅱ (143 weeks), Group Ⅲ (194 weeks), and Group Ⅳ (246 weeks). Samples were harvested from previously-conducted field trials, and stored at +4 ℃. A-PAGE and SDS-PAGE methods were utilized to separate gliadin and glutenin fractions, respectively. A qualitative calibration model based on the Support Vector Machine (SVM) method was generated and validated using NIR spectra taken from samples. Results indicated storage length did not have an effect on molecular band fractions. Use of this method would not be considered an effective tool for discrimination of samples stored for different lengths of time. Spectral techniques may have potential in sorting samples based on their storage time. The SVM calibration model generated here had an acceptable true classification rate (over 80%) for separating all groups, while only Groups Ⅱ and Ⅳ were precisely separated (100% true classification rate) in the validation step..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1266 (2016)
Natural Bond Orbitals (NBO), Natural Population Analysis, Mulliken Analysis of Atomic Charges of 2-［(2, 3-Dimethylphenyl) Amino］Benzoic Acid
N. Balamurugan, S. Sampathkrishnan, and C. Charanya
The spectroscopic properties of the FT-IR and FT-Raman spectra of the 2-［(2,3-dimethylphenyl)amino］benzoic acid (DMPABA) compound have been recorded in the region 4 000～400 cm-1. The molecular structure, vibrational wavenumbers were calculated using DFT (B3LYP) method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The GThe spectroscopic properties of the FT-IR and FT-Raman spectra of the 2-［(2,3-dimethylphenyl)amino］benzoic acid (DMPABA) compound have been recorded in the region 4 000～400 cm-1. The molecular structure, vibrational wavenumbers were calculated using DFT (B3LYP) method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The Geometrical structure, vibrational frequencies, corresponding vibrational assignments of 2-［(2,3-dimethylphenyl)amino］benzoic acid (DMPABA) have been investigated experimentally and theoretically using Gaussian03 software package. The detailed Molecular orbital calculation such as Natural Bond Orbitals (NBO), Natural Population Analysis (NPA) and Mulliken analysis of atomic charges is also calculated..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1273 (2016)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 4, 1 (2016)
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