Journals >Spectroscopy and Spectral Analysis
Contents
2016
Volume: 36 Issue 10
67 Article(s)
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Research Article
Study of Proteins Based on Surface-Enhanced Raman Spectroscopy (SERS)
CHEN Lei, KONG Wei-he, HAN Xiao-xia, and ZHAO Bing
This article outlines the recent progress in surface enhanced Raman spectroscopy (SERS) based proteins applications. SERS is a specific Raman spectroscopic technique that provides enhanced Raman signals (several orders of magnitude greater than normal) for numerous Raman-active analyte molecules adsorbed onto rough metThis article outlines the recent progress in surface enhanced Raman spectroscopy (SERS) based proteins applications. SERS is a specific Raman spectroscopic technique that provides enhanced Raman signals (several orders of magnitude greater than normal) for numerous Raman-active analyte molecules adsorbed onto rough metal surfaces. SERS is a sensitive, selective, and versatile technique that lends to fast data acquisition in actual time. Therefore, SERS has undergone rapid development because of its technical advantages in instrumentation, data analysis methods and its multiple biological applications. This article highlights several representative areas in proteins where SERS could be employed. Some of the proteins applications of SERS are more maturely developed, whereas others are in their initial stages of development (in laboratories). This article discusses the recent developments in SERS based quantitative analysis: directly with different substrates (e.g. biomolecules on electrodes, colloidal particles, and periodic pattern structure and tip based substrates). Furthermore, SERS based techniques are advantageous for obtaining valuable information on protein-protein, protein-ligand, and protein-drug recognitions via spectral differences among molecular bridges. SERS based techniques show considerable promise for qualitative and/or quantitative analyses of biological systems..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3087 (2016)
Characteristics Analysis of the Thyroid Gland Surface of Normal Human with Fourier Transform Infrared (FTIR) Spectra
WU Min, ZHANG Wei-tao, TIAN Pei-rong, LING Xiao-feng, and XU Zhi
In order to obtain 240 cases of the surface Fourier transform infrared (FTIR) spectra of normal human thyroid gland, 120 healthy volunteers were enrolled in this study and scanned by using two mid-infrared optical fibers equipped with an attenuated total reflectance (ATR) to probe through the skin of two lobes of thyroIn order to obtain 240 cases of the surface Fourier transform infrared (FTIR) spectra of normal human thyroid gland, 120 healthy volunteers were enrolled in this study and scanned by using two mid-infrared optical fibers equipped with an attenuated total reflectance (ATR) to probe through the skin of two lobes of thyroid gland. Then whether there were differences between the surface FTIR spectra of the right lobe and that of the left part of the normal human thyroid gland was explored by comparing the 35 variables of 12 bands, including peak positions, relative intensity ratios and full width at half maximum of FTIR spectrums. Also the spectra characteristics of unique absorbent bands that represent changes of structure and quantity of variance biochemical substances such as nucleic acids, proteins and carbohydrates were illustrated. Results indicated that the surface FTIR spectra of the right part and that of the left part of the normal human thyroid gland were generally coincided, with statistically significant differences in four spectrum parameters, includingF1 640, P2 920, P1 040 and I2 920/I1 460. A series of data about the 90% normal reference range of the unique spectrum parameters in the surface FTIR spectra of normal human thyroid gland was gained, and a standard average infrared spectrogram which can fully represent the basic features of normal human thyroid gland was plotted. The conclusions above could be used as a reference for clinical diagnosis of thyroid diseases with FTIR spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3092 (2016)
Nocturnal Atmospheric NO3 Radical Monitoring and Analysis in Beijing with Cavity Ring Down System
WANG Dan, HU Ren-zhi, XIE Pin-hua, QIN Min, and XING Xing-biao
The oxidizability of NO3 radical in the nocturnal atmosphere is comparable with that of diurnal OH radical. Given the importance of NO3 radical in the nocturnal chemical process, accurate measurement of its concentration and analysis its nocturnal chemical process have important significance. The article introduces cavThe oxidizability of NO3 radical in the nocturnal atmosphere is comparable with that of diurnal OH radical. Given the importance of NO3 radical in the nocturnal chemical process, accurate measurement of its concentration and analysis its nocturnal chemical process have important significance. The article introduces cavity ring-down spectroscopy (CRDS) instrument which is applied to measure atmospheric NO3 radical. Light from a red laser diode (the wavelength is 662 nm and line width is 0.3 nm) is coupled on-axis into an optical cavity formed by a pair of high-reflectivity mirrors (R≥99.998 5%) to achieve an effective absorption path length of approximately 20km. And it researches nocturnal chemical process of NO3 radical in view of the fall and winter heavy traffic areas. The measurement of NO3 radical with cavity ring-down spectroscopy was performed in Beijing from October 29 to November 15, 2014. During the observation, the concentration of NO3 radical is relatively low with the maximum of NO3 radical concentration of 50pptv and the average of its concentration of approximately10 pptv. Combining of NO2, O3 and NO data, the observation results are analyzed. The NO3 production rates ranging from 0.04 to 1.03 pptv·s-1 were calculated throughout the observation, and NO3 lifetime averaged at 68 s. The NO3 loss process in the atmosphere is further analyzed. Combining of related auxiliary data, the influence of different humidity as well as particulate matter concentrates on the atmospheric NO3 removal is researched. When atmospheric RH≥60% and PM2.5 concentration mainly greater than 60 μg·m-3, the correlation coefficient of the logarithmic correlation between NO3 lifetime and NO2 mixing ratio is 0.79, NO3 is mainly removed by the indirect loss process; however, when atmospheric RH≤40% and the concentration of PM2.5 mainly smaller than 60 μg·m-3, because of the observation site is close to national highway and influenced by local pollution source, the direct loss process is main; When atmospheric 40%
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3097 (2016)
Relationship Exploration of Chemical Content, Complex Dielectric Constant and Spectral Features of Rocks
YANG Chang-bao, WU Meng-hong, ZHANG Chen-xi, YU Yan, XU Meng-long, LIU Wan-song, and CHEN Sheng-bo
In this research, 97 pieces of rock in Xingcheng, Liaoning Province, China were collected to measure the spectral reflectance in 350~2 500 nm, chemical content, and complex dielectric constant of some samples. The absorption depths were calculated by using continuum- removal method. With correlation analysis method, twIn this research, 97 pieces of rock in Xingcheng, Liaoning Province, China were collected to measure the spectral reflectance in 350~2 500 nm, chemical content, and complex dielectric constant of some samples. The absorption depths were calculated by using continuum- removal method. With correlation analysis method, two kinds of correlation curves were obtained based on the theory of spectral characteristics of chemical contents and the principle of dielectric constant. One described the relationship between chemical content and spectral absorption depth, and the other one represented the correlation of complex dielectric constant and reflectance. By summarizing curves morphological characteristics, several conclusions were drawn as follows: (1)There was a strong correlation between the chemical content (SiO2, Al2O3, CaO, K2O, MgO, burnt-loss) and spectral absorption depth in 1 900~2 500 nm, furthermore, at around 1 900, 2 200, 2 300 nm and other identifying characteristic bands, local extreme maximum / minimum values appeared. At Fe3+ characteristic band (400~550 nm), correlation coefficient reached -0.406 between Fe2O3 content and absorption in igneous rock samples collection. Exploring the relationship between rock spectral absorption features and its chemical contents had a positive effect on metallogenic prediction and lithology identification with remote sensing image. (2) Reflectance and complex dielectric constant were negatively correlated totally, compared with the imaginary part; the real part had a better relation reached -0.753 at around 1 900 nm. Curves showed that there were great correlations around 1 900 and 2 200 nm, so, our study adopted different models to simulate response relationships. Dielectric constant of media is one of the basic physical properties, and now most analyses of existing research between electromagnetic characteristics and dielectric constant are studied in microwave band, however, our research is conducted in visible and near infrared range. The conclusions will be useful for further exploration on dielectric characteristics and spectral features of rocks..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3103 (2016)
Effect of the Infrared Absorption Properties of Sodium Nitrate with Photonic Crystal
ZHANG Jing, SUN Peng, NIE Zhen-ming, WANG Jie-sheng, LI Chun, LI Jun-jie, and YUAN Guang
The two-dimensional photonic crystal (Ni mesh with square lattice of 10 μm) was prepared and Ni film was thickened to 3 μm by electroplating. Its optical properties and its influence on the infrared absorption of sodium nitrate were investigated. The results show that there is a transmission peak centered at 1 450 cm-1The two-dimensional photonic crystal (Ni mesh with square lattice of 10 μm) was prepared and Ni film was thickened to 3 μm by electroplating. Its optical properties and its influence on the infrared absorption of sodium nitrate were investigated. The results show that there is a transmission peak centered at 1 450 cm-1 under normal incidence, and the peak covered the frequencies ranging from 1 300 to 1 500 cm-1, the antisymmetric stretching vibration of nitrate. Moreover, the change of absorption intensities of nitrate’s antisymmetric stretching vibration is essentially consisting with the transmittance of photonic crystal. It indicates that the absorption intensity of sodium nitrate is improved by the modulated infrared light..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3110 (2016)
Out-of-Band Radiation and Spatio-Temporal Characterization of Gd Target Laser Plasma Sources
SONG Xiao-lin, SONG Xiao-wei, DOU Yin-ping, TIAN Yong, XIE Zhuo, GAO Xun, and LIN Jing-quan
In this paper, an Nd∶YAG laser with 10ns pulse width and output wavelength of 1 064 nm was employed to ablate Gd metal target and Gd-doped glass target for plasma generation. The out-of-band (OOB) radiation of extreme ultraviolet sources with the two target configurations was comparatively studied. It has been found thIn this paper, an Nd∶YAG laser with 10ns pulse width and output wavelength of 1 064 nm was employed to ablate Gd metal target and Gd-doped glass target for plasma generation. The out-of-band (OOB) radiation of extreme ultraviolet sources with the two target configurations was comparatively studied. It has been found that the continuous radiation emitted by the plasma is the main component of the out-of-band radiation. The spectral distribution of the continuum emission matches that of blackbody radiation with a temperature of about 5 eV. And it is also found that the intensity of OOB radiation can be considerably decreased by using Gd-doped glass target. Optical Emission Spectroscopy (OES) has been used to analyze the temporal and spatial behaviors of electron temperature (Te) and density (Ne) of the Gd-doped glass target plasma, and experimental results show that temporal evolution of electron temperature and density of the plasma are found to be decayed exponentially with the increasing of delay time. At 125 ns after laser irradiation, electron temperature and density were 4 eV and 1.2×1018 cm-3 respectively, and then decreased to 1.5 eV and 8×1017 cm-3 with delaying time of 250 ns. On the other hand, spatial evolution of electron temperature and density show that both of them first increase and then decrease in the region of 1~10 mm from the target surface. The electron temperature and electron density achieves the maximum of 2.6 eV and 8.5×1017 cm-3, respectively, when the probe location away from the target surface 6 mm..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3114 (2016)
RGBW Signal Mapping Algorithm Assessment Based on Colorimetry
PAN Ding-ping, JIN Wei-qi, QIU Su, and FAN Qiu-mei
With the continuous pursuit of high brightness and low power consumption display technology, RGBW display technology has been attracting increasing attention in the world. Various kinds of displays based on this technology have been produced in the market. The key of this technology is signal mapping algorithm which coWith the continuous pursuit of high brightness and low power consumption display technology, RGBW display technology has been attracting increasing attention in the world. Various kinds of displays based on this technology have been produced in the market. The key of this technology is signal mapping algorithm which converts RGB signal into RGBW signal without color distortion and compatible with different sub-pixel layouts. This paper, on the basis of five kinds of signal mapping algorithms, analyzes the mode of action of newly added white sub-pixel affects display color, and the display performance affected by four kinds of sub-pixel layouts; it proposes the corresponding condition of excellent signal mapping algorithm based on colorimetry and deduces the universal equation of excellent signal mapping algorithm and brightness factor which could measure the ability of enhancing brightness. The simulation experiment shows that the signal mapping algorithm which satisfies universal equation could be able to maintain the hue and saturation better. The signal mapping algorithm’s ability to enhance brightness is effectively characterized by brightness factor. In conclusion, the proposed universal equation can be used to evaluate existing signal mapping algorithms, and it provides theoretical references for the research of new signal mapping algorithm which could be compatible with different hardware parameters and sub-pixel layouts, promote the popularization of RGBW display technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3119 (2016)
Experimental Study on the Characteristics of Chemiluminescence in Coal Water Slurry Diffusion Flames Based on Hot Oxygen Burner Technology
HU Chong-he, GUO Qing-hua, SONG Xu-dong, GONG Yan, and YU Guang-suo
Most published works focused on the characteristics of chemiluminescence in homogeneous flames, but the research about radiation spectrum in heterogeneous flames was still limited. In this paper, improved hot oxygen burner (HOB) technology is applied to ignite coal water slurry (CWS) directly in the open space, for staMost published works focused on the characteristics of chemiluminescence in homogeneous flames, but the research about radiation spectrum in heterogeneous flames was still limited. In this paper, improved hot oxygen burner (HOB) technology is applied to ignite coal water slurry (CWS) directly in the open space, for stable combustion. Radiation spectrum and two-dimensional OH* chemiluminescence in methane and CWS diffusion flames are measured by a fiber optic spectrometer and a high-spatial-resolution UV imaging system. The results show that OH* (309.12 nm), CH* (431.42 nm) and C2* (463.52~563.43 nm) radicals exist in both methane and CWS diffusion flame, but Na* (589.45 nm), Li* (670.88 nm), K* (766.91, 770.06 nm), H* (816.04, 819.99 nm) radiation spectrum line and continuous black-body radiation have been detected only in the CWS flame. These differences can be used to characterize the combustion or gasification of CWS and distinguish whether CWS is ignited or not. In addition, the injection of CWS into methane flame leads to a significant reduction in OH* and an increase in C2* and CH* radiation intensity. This is because a lot of heat is absorbed in the processes of CWS combustion reactions. Then the generation of CH is inhibited, and the production of OH* is reduced. The increase of C2* and CH* is due to simple substance carbon produce more after injecting CWS. Besides, axial OH* radiation intensity increases at first then decreases, and the position of peak intensity is closer to outlet of hot oxygen burner compared with methane flames. Radial OH* radiation distribution is bimodal in methane flame because reactions take place in the thin layer where methane and oxygen meet. However, in CWS flame, radial OH* radiation distribution is always unimodal since CWS diffuses fiercely and mixes with oxygen sufficiently. As the ratio of oxygen atom to carbon atom (［O/C］e) increases, the reaction region of OH* radicals becomes larger in methane and CWS flame. This indicates that increasing oxygen can promote reactions and benefit OH* radicals’ generation. Moreover, with the increase of CWS flow, reaction center is closer to burner outlet, OH* distribution range and peak intensity decrease obviously, CH*, C2*, Na*, Li*, K*, H* and black-body radiation intensities markedly rise. And these characteristics can reflect the changes of operation loads..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3127 (2016)
The Inside Charge Behavior of Organic Light-Emitting Diodes Investigated with Transient Electroluminescent Measurements
YANG Zhao-kun, ZHAO Su-ling, XU Zheng, and HUANG Qing-yu
Transient electroluminescent measurement system is used to study the inside charge behavior of prepared organic light-emitting diodes (OLEDs) in this article. Two rectangular pulses with a fixed time interval are supplied on the device. We can analyze the inside charge storage and the emitting process by measuring the Transient electroluminescent measurement system is used to study the inside charge behavior of prepared organic light-emitting diodes (OLEDs) in this article. Two rectangular pulses with a fixed time interval are supplied on the device. We can analyze the inside charge storage and the emitting process by measuring the transient EL and transient current of the device. OLEDs based on the m-MTDATA∶3TPYMB (1∶1) system was prepared. We found that the stable EL intensity increase when the second pulse is supplied. And the increment reduced with the increased current. We also find the electroluminescent under the second pulse decayed faster than that of the first pulse. This is because of the quenching due to the polaron-exciton effect (TPQ) is more serious in the emitting layer under the second pulse..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3134 (2016)
Research on the Development of Light Blending Model for Smart LED Lighting
LIU Qiang, WAN Xiao-xia, LI Jun-feng, LIANG Jin-xing, LI Bi-hui, and WANG Qi
The color of the LED smart light is tunable by its inner equipped micro-processing systems. Therefore, it could provide significant improvement for the smart lighting conditions, such as museum lighting and home lighting. At present, the limitation of the current lighting blending technology remarkably affects the applThe color of the LED smart light is tunable by its inner equipped micro-processing systems. Therefore, it could provide significant improvement for the smart lighting conditions, such as museum lighting and home lighting. At present, the limitation of the current lighting blending technology remarkably affects the application of smart lighting technology and people could not make full use of the adjustability of the smart luminaries. In this research, a novel light blending model was proposed based on BP neural network and active set algorithm. The models could effectively simulate the nonlinear relationship between the device control values of the smart light and the output radiance spectrum of the light. Particularly, a BP neural network-based forward model for LED light blending was firstly proposed, which could accurately calculate the spectral radiance power distribution from the device control values. Afterwards, based on forward model, an active set algorithm-based backward model was developed, which could precisely predict the device control values from the desired spectral radiance power distribution. The experimental result indicates that the proposed method could accurately achieve the light blending controlling of smart LED light, with a CIEUCS Duv value of 0.002 7, which is significantly smaller than the just noticeable difference value of human vision. The authors believe that the proposed method will provided effective support for the development of smart LED lighting in near future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3138 (2016)
The NIR Spectral Characteristics and Meaning of Fault Gouge from Kaxiutata Iron Deposit, Inner Mongolia
DAI Dong-le, and CAO Jian-jin
Kaxiutata iron deposit is a skarn type magnetite deposit located in Inner Mongolia, China. There are many faults developed after metallogenic period. In this study, NIR analysis method is adopted to identify the mineral composition of subsurface and surface fault gouge from mining area. Through the characteristic peaksKaxiutata iron deposit is a skarn type magnetite deposit located in Inner Mongolia, China. There are many faults developed after metallogenic period. In this study, NIR analysis method is adopted to identify the mineral composition of subsurface and surface fault gouge from mining area. Through the characteristic peaks, it is was identified that there are mainly mafic mineral in the subsurface fault gouge and salic minerals in the surface fault gouge, the sand sample for comparison contain both two types of minerals. The result of analysis of all three sets of sample is in accordance with the geological background of the sampling spot. According to this research, due to the main composition of the fault gouge in the mineralization area are clay formed due to the faulting movement and altered minerals formed in early metallogenic period. NIR analysis technology is suitable for this type of sample, to use this technology, we can identify the clay mineral in the fault gouge, and further speculate the composition of protolith of clay, we can also indentify the altered minerals formed in metallogenic period, and provide useful information for study of hydrothermal deposit..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3144 (2016)
A New Feature Extraction Method of Near-Infrared Spectra Based on the Addition of Historical Data
LI Hao-guang, LI Wei-jun, QIN Hong, ZHANG Li-ping, DONG Xiao-li, and YU Yun-hua
In traditional qualitative analysis of near-infrared (NIR) spectra, the stability of recognition models is decreased when new varieties of samples are added into the model. In order to improve the robustness of the model, a new feature extraction method based on the addition of historical data was put forward. The NIR In traditional qualitative analysis of near-infrared (NIR) spectra, the stability of recognition models is decreased when new varieties of samples are added into the model. In order to improve the robustness of the model, a new feature extraction method based on the addition of historical data was put forward. The NIR training samples will be collected first, after that the historical data of the same species is added to constitute a larger and richer dataset. Then, the pretreated data of these training samples is projected to the feature space, which is constructed by feature extraction using partial least squares (PLS) based on the above dataset. Subsequently, orthogonal linear discriminant analysis (OLDA) is employed to extract features of the projected data. 18 varieties of corn seeds were taken as study subject, the comparative experiments with and without historical data are implemented respectively, and then the biomimetic pattern recognition (BPR) method is applied to verify the efficiency of the method proposed. The results suggest that the method adopted can improve the robustness of recognition model more effectively compared with the method without historical data. It maintains the high correct recognition ratios when new varieties are added into the model. Besides that, the recognition effect on test sets of the different days remains the same basically in the condition of same PLS dimensions. Therefore, the dimension of feature extraction can be set to some fixed values in recognition software. In this way, it can keep out of the trouble of manually modifying the optimal PLS parameter in recognition software if new varieties need to be added into the model. The experiment results of the thesis manifested the effectiveness of the proposed method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3148 (2016)
Logistics Process Safety System of Table Grapes Based on NIR
CHEN Xiao-yu, ZHANG Xiao-shuan, ZHU Zhi-qiang, ZHANG Peng, and MU Wei-song
In view of the actual logistics process of table grapes and the situation that fresh keeping agents based on sulfur dioxide are commonly used in table grape logistics, we studied the shelf life prediction method of table grapes under 4 temperatures and constant concentrations of sulfur dioxide based on near infrared spIn view of the actual logistics process of table grapes and the situation that fresh keeping agents based on sulfur dioxide are commonly used in table grape logistics, we studied the shelf life prediction method of table grapes under 4 temperatures and constant concentrations of sulfur dioxide based on near infrared spectrum (NIR) and the evolution of texture in this work. Logistics process safety system based on shelf life prediction was designed to reduce the loss of table grapes in the logistics. The change of texture is an important cause of postharvest table grapes to end their shelf life in postharvest logistics. In this work, we used SO2 concentration sensors to control solenoid valves, and obtained the set SO2 concentrations by automatic compensation mechanism. The evolutions of table grape texture under different concentrations of sulfur dioxide were studied as well as the influence of temperature. The NIR pretreatment effects of multiplicative scatter correction and the first S-G derivation were compared. The table grape texture nondestructive testing model built base on NIR and partial least squares regression achieved a determination coefficient of 0.93 and the root mean squared error (RMSE) was 1.70. In full cross-validation, the prediction accuracy reached to 0.81 and got a RMSE of 2.91. Research indicated that the NIR detection combined with the quality change modeling and information technology could be used to improve the logistics process safety management efficiency of postharvest fruits and vegetables..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3154 (2016)
Infrared Spectrum Studies of Coatings under Irradiation of Sunlight and Ultraviolet
LI Li-xia, CAO Bing, SUN Yu-meng, LI Hong-yan, XIAO Qiang, NI Xiao-hui, and YI Wen-ping
Degradable resin- coated controlled release fertilizer is one of the hottest current research focuses in the field of fertilizer. In terms of practical application, the photodegradability characteristics of three kinds of coatings including polyethylene/hydrophilic nano-TiO2 composite, polyethylene/hydrophilic nano-TiODegradable resin- coated controlled release fertilizer is one of the hottest current research focuses in the field of fertilizer. In terms of practical application, the photodegradability characteristics of three kinds of coatings including polyethylene/hydrophilic nano-TiO2 composite, polyethylene/hydrophilic nano-TiO2 composite and pure polyethylene were analyzed under irradiation of sunlight and ultraviolet by ATR-FTIR, which was aimed to know their degradation behaviors under two conditions. The result showed that under irradiation of sunlight and ultraviolet, the type of functional group was not changed with the addition of the photo-catalyst, but the photo-catalyst just had an effect on intensity of functional groups. The trend was polyethylene/hydrophobic nano-TiO2 composite>polyethylene/hydrophilic nano-TiO2 composite>pure polyethylene. Furthermore, sunlight and ultraviolet had different effects on molecular structures of coatings. Under irradiation of sunlight, crosslinking reaction took place and ether bond was generated among the carbon chain of polyethylene except for the form of hydroperoxides. Then, carbon chain continued being oxidized to form carbonyl group. The existence of carbonyl group promoted the further degradation of coatings; under irradiation of ultraviolet, high local concentrations of reactive oxygen species were produced and the ability to attack the carbon chain of polymer was strong. Thus, the long alkyl chain of polyethylene was quickly oxidized to form intermediate products containing carbonyl groups. However, the irradiation experiment of ultraviolet didn’t fully reveal the degradation behavior of coatings..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3159 (2016)
Investigation on Spectral Characteristic and Threshold Behavior of Network Structure of Ge-Sb-S Chalcogenide Glasses
HUANG Yi-cong, CHEN Fei-fei, QIAO Bei-jing, DAI Shi-xun, XU Tie-feng, and NIE Qiu-hua
Two series of chalcogenide glasses in Ge-Sb-S ternary system were synthesized with melt-quenching method. The phycochemical properties and spectral characteristic of glasses with different content of Ge and Sb were obtained with a series of measurements, and the systematic analysis on the change of optical properties wTwo series of chalcogenide glasses in Ge-Sb-S ternary system were synthesized with melt-quenching method. The phycochemical properties and spectral characteristic of glasses with different content of Ge and Sb were obtained with a series of measurements, and the systematic analysis on the change of optical properties was conducted in terms of microstructure of glasses combined with the Raman spectra. With constraint theory based on mean coordination number (Z), we described the variation trend of network structure directly. It was found that as long as the value of Z reaches 2.6, new vibration peaks would be formed in the Raman spectra indicating the presence of threshold behavior as well as the change of the network structure of the Ge-Sb-S glasses which could be expressed in a specific varition in the number of metal bonds and the nonmetal bonds. The appearance of new functional groups in the network have changed the total bond energy of glasses, and then affected the energy band structure of glasses representing the corresponding threshold behavior of the value of optical band gap (Eopg)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3163 (2016)
Quick Discrimination of Rice Storage Period Based on Manifold Dimensionality Reduction Methods and Near Infrared Spectroscopy Techniques
LIN Ping, CHEN Yong-ming, and ZOU Zhi-yong
This paper proposed a method for rapid identification of rice storage period based on manifold dimensionality reduction algorithms and near infrared spectroscopy (NIRS) technique. The reflection spectrum curve of old rice and new rice were obtained with a field spectroradiometer and the acquired spectral data was preprThis paper proposed a method for rapid identification of rice storage period based on manifold dimensionality reduction algorithms and near infrared spectroscopy (NIRS) technique. The reflection spectrum curve of old rice and new rice were obtained with a field spectroradiometer and the acquired spectral data was preprocessed with direct orthogonal signal correction method (DOSC) to filter the independent signal from the spectral data which is irrelevant with the dependent variable Y array and eliminate the influence and interference of the irrelevant information in the following chemometric analysis. The Durbin-Watson test and Run test methods were utilized to detect the nonlinearity which exists in the spectral data structure. The enhanced partial residual plot analysis method (Augmented partial residual plot) was employed to quantitative analysis of the degree of nonlinearity of the spectral data. Popular linear manifold dimensionality reduction methods including principal component analysis (PCA) method and multidimensional scaling analysis (MDS) method and popular nonlinear manifold dimensionality reduction methods including Isometries mapping method (ISOMAP), locally linear embedding (LLE) method and Laplacian Eigenmap method (LE) were used to extract the real variable from the preprocessed spectral data. Then, the intrinsic variable was taken as the input of the kernel partial least squares method (KPLS) to establish the relationship between the intrinsic variables and the storage time of rice samples. The number of experiment samples of the new rice and the old rice were 200 respectively and randomly separated into the training set with 300 samples and the test set with 100 samples. Through comparing the prediction results of the regression models which were established with different manifold reduction methods, the experiment results show that the prediction effects of the nonlinear-based models are superior to the linear-based models. Finally, the KPLS model established with 40 true variables extracted with ISOMAP approach achieved the optimal prediction effect. The prediction correlation coefficient (R2p), RMSEP (RMSEP) and relative prediction error value (RPD) were 0.917, 0.187 and 2.698, respectively. It was concluded that NIRS combined with ISOMAP-KPLS method can be successfully used to determine the storage period of rice accurately and quickly. The study provides a scientific means for rapid non-destructive detecting for rice storage period research in the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3169 (2016)
Mid-Infrared Trace CH4 Detector Based on TDLAS-WMS
QU Shi-min, WANG Ming, and LI Nan
In order to detect trace methane (CH4) with non-contact method, a trace CH4 detector is designed and developed with the combination of tunable diode laser absorption spectroscopy (TDLAS) and wavelength modulation spectroscopy (WMS) detection technology, using the absorption line (1 332.8 cm-1) of CH4 in mid-infrared baIn order to detect trace methane (CH4) with non-contact method, a trace CH4 detector is designed and developed with the combination of tunable diode laser absorption spectroscopy (TDLAS) and wavelength modulation spectroscopy (WMS) detection technology, using the absorption line (1 332.8 cm-1) of CH4 in mid-infrared band. The instrument uses mid-infrared quantum cascaded laser (QCL) with centre wavelength at 7.5 μm, and uses the method of changing the injecting current (0.6～1.6 A) of QCL with fixed working temperature to make the emission wavelength of QCL to scan the methane’s absorption line (1 332.8 cm-1) via tuning parameters 0.2 cm-1·A-1. In terms of optical structure, the instrument using a gas absorption sealed herriott cell with 76 m long optical path, cooperating with difference detection optical path, reduces the noise which caused by the fluctuation of QCL, and guarantees the detection of trace CH4. In the experiment, we adopted minimum mean square error criterion to fit the relationship between methane concentration and harmonic peak signal. In addition, the minimum detection limit is 40×10-9, and the relative error of test results is 0.09%., The stability is better than 2.8%, which verify the feasibility of the instrument..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3174 (2016)
Identification of Brake Fluid Brands, New and Used Brake Fluid with Discriminant Analysis Based on Near-Infrared Transmittance Spectroscopy
ZHANG Yu, TAN Li-hong, and HE Yong
Near-infrared transmittance spectroscopy was used to identify brake fluid brands, new and used brake fluid of each brand. The transmittance spectra of the new and used samples of 4 different brands of brake fluid, including BMW, Toyota, Volvo and Castrol were collected. PCA was conducted to the spectral data of the newNear-infrared transmittance spectroscopy was used to identify brake fluid brands, new and used brake fluid of each brand. The transmittance spectra of the new and used samples of 4 different brands of brake fluid, including BMW, Toyota, Volvo and Castrol were collected. PCA was conducted to the spectral data of the new samples of the four brake fluid and the spectral data of the new and used samples of each brand. The PCA scores scatter plot indicated that there were differences among the four brands of brake fluid, and there were also differences between new and used samples of each brand. Optimal wavelengths were selected for identifying different brands and new and used samples of each brand by loadings of PCA. Classification models were built using the optimal wavelength, including Partial least squares-discriminant analysis (PLS-DA), Linear discriminant analysis (LDA), Soft independent modeling of class analogy (SIMCA), k-nearest neighbor algorithm (KNN), Random forest (RF), Back propagation neural network (BPNN), Radial basis function neural network (RBFNN), Extreme learning machine (ELM), Support vector machine (SVM), Least-squares support vector machine (LS-SVM). All classification models obtained good performances, the classification accuracy of the calibration set and the prediction set are 100% for most models. Compared with other three brands, new and used samples of Castrol showed slighter difference, and KNN and LS-SVM models performed worse with classification accuracy under 100% in the calibration set. The overall results indicated that near-infrared transmittance combined with optimal wavenumber selection and classification methods could be used to identify brake fluid brands, new and used brake fluids, the results of this study could provide theoretical support for developing online and portable devices..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3179 (2016)
Determination of Tomato’s SSC and TS Based on Diffuse Transmittance Spectroscopy
WANG Fan, LI Yong-yu, PENG Yan-kun, and ZHENG Xiao-chun
In order to meet the demands for rapid and safe nondestructive testing of fruit and vegetable quality, tomato detection system with a special circular light source was built based on the visible / near infrared diffuse transmission principle. Taking soluble solids content (SSC) and total sugar (TS) as the internal qualIn order to meet the demands for rapid and safe nondestructive testing of fruit and vegetable quality, tomato detection system with a special circular light source was built based on the visible / near infrared diffuse transmission principle. Taking soluble solids content (SSC) and total sugar (TS) as the internal quality index, the prediction of 58 tomato samples was carried out by using this system. First, we collected the spectral data of four points for each tomato. Second, Savitzky-Golay smooth(SG-Smooth), standard normal variable transformation(SNV), multiplication scattering correction(MSC), first derivative (FD) and other methods were used to process the original spectral curve before the partial least squares regression(PLSR) model was established. Finally, we validated the established model. The results show that the correlation coefficient (r) of calibration and prediction of the SSC prediction model -are 0.995 6 and 0.976 0 when using 10 point SG-smooth, and the root mean square error of calibration and prediction are 0.052 4% and 0.082 3%. The partial least square regression (PLSR)model, with respect to the first derivative (FD) spectra, provides better prediction performance for total sugar of tomato, with correlation coefficient (r) of calibration of 0.969 1 and 0.972 9, and prediction, root mean standard error of 0.423 8% and 0.454 9%. In the experimental verification of the prediction model, the relationship of SSC between predicted and true value is 0.985 5, root mean square error is 0.066 3°Brix, the relationship of TS between predicted and true value is 0.944 9 while root mean square error is 0.571 5%. The results show that the content of soluble solids and total sugar in tomato can be realized by using visible / near infrared diffuse reflectance spectroscopy. It provides a real-time, nondestructive and rapid detection method for the evaluation of the internal quality of tomato, and provides a theoretical basis for its online grading..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3185 (2016)
Raman Spectroscopic Study of the Structure of CaO-SiO2-Al2O3-Based Flux
GAO Jin-xing, WEN Guang-hua, HUANG Ting, SUN Qi-hao, TANG Ping, and LIU Qiang
Due to the ［Al］ reaction with the CaO-SiO2-based mold flux used in the high-Al steels continuous casting processes, decreasing the SiO2 content is decreased and the Al2O3 content in mold flux is increased, thus converting the original CaO-SiO2-based mold flux into a CaO-SiO2-Al2O3-based mold flux. This conversion of thDue to the ［Al］ reaction with the CaO-SiO2-based mold flux used in the high-Al steels continuous casting processes, decreasing the SiO2 content is decreased and the Al2O3 content in mold flux is increased, thus converting the original CaO-SiO2-based mold flux into a CaO-SiO2-Al2O3-based mold flux. This conversion of the mold fluxes can cause the problem of high-Al steels continuous casting. Hence, study on the structural characteristics of the CaO-SiO2-Al2O3- based mold flux can provide fundamental data to design optimum fluxes for high Al-containing steels. In this paper, the structural characteristics of the CaO-SiO2-based and CaO-SiO2-Al2O3-based flux were studied by Raman spectroscopy. The results have shown that, the CaO-SiO2-based flux was the silicate structure whose main micro-structure units were Q0, Q1, Q2 and Q3. The network breakers prefer to depolymerize the silicate network in CaO-SiO2-Al2O3-based flux. While the CaO-SiO2-Al2O3-based flux with low SiO2 content, the ［AlO4］ tetrahedron was entered the silicate network and the melt converted into the aluminosilicates structure, the formation of Al-O-Al linkages and Si-O-Al linkages increased the degree of disorder of network. The results of Li2O replace Na2O and CaO replace MgO have shown that the ions will influence the formation of ［AlO4］ tetrahedron linkages. CaF2 replace CaO shown that the polymerization degree of mold slag decreased first, and then increased with the content of CaF2 more than 13 mol%. So, the influences of the ions type and the ions content on the structure were both need considered while designing the CaO-SiO2-Al2O3-based flux..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3190 (2016)
Raman and Visible-Near Infrared Spectra of Cu(InGa)Se2 Films
XU Dong-mei, PAN Kun, LIU Xu-wei, WANG Xue-jin, WANG Wen-zhong, LIANG Chun-jun, and WANG Zhi
Cu(InxGa1-x)Se2(CIGS) precursor films were prepared on ITO glass with potentiostatic electrodeposition. High quality CIGS films were obtained by selenization of the precursor films at high temperature in tubular furnace full of argon gas. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis-NIR spectrCu(InxGa1-x)Se2(CIGS) precursor films were prepared on ITO glass with potentiostatic electrodeposition. High quality CIGS films were obtained by selenization of the precursor films at high temperature in tubular furnace full of argon gas. X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis-NIR spectroscopy were used to characterize the structure, morphology, composition and Vis-NIR absorption of CIGS films, respectively. XRD results show the selenized CIGS films have a preferential orientation (112) with average crystallite of 24.7 nm. Raman spectroscopy reveals that the CIGS films are pure quaternaryphases with chalcopyrite structure, and without binary or ternary phases in the films. Vis-NIR measurements determine that the bandgap of CIGS increases with the increase of Ga concentration in the film. When the Ga concentration is 5.41%, its bandgap is about 1.11 eV, and the calculated ratio of Ga to (Ga+In) is 16.3%, which is less than the ratio of Ga to (Ga+In), 21.4%, measured by SEM. This indicates that crystallinity of CIGS filmsneeds to be further improved. All the measurements demonstratethat optimum ITO/CIGS has a promising application in bifacial solar cells. In this paper, we provide a newmethodtoelectrodeposit low cost CIGS precursor films and a new method forselenization ofthe precursor films at high temperature. As a result, theuniform and compact CIGS films with good adhesion on ITO are successfully fabricated by these methods. The above characterization show that we have obtained CIGS films with high crystallinity, near stoichiometry, few impurity phases and superior light absorption. Electrodeposition, like magnetron sputtering, is very suitable for large-scale industrial production. The research work in this paper is therefore important and considerable to massive production of electrodeposition of CIGS films..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3197 (2016)
Identification Study of Edible Oil Species with Laser Induced Fluorescence Technology Based on Liquid Core Optical Fiber
FAN Yuan, WU Rui-mei, AI Shi-rong, LIU Mu-hua, YANG Hong-fei, and ZHENG Jian-hong
A laser- induced fluorescence detection set based on liquid core optical fiber was established in this study. Eight edible oils were discriminated by using this detection set combined with chemometrics method. The effect of length of liquid core optical fiber on laser induced fluorescence spectrum was explored, and theA laser- induced fluorescence detection set based on liquid core optical fiber was established in this study. Eight edible oils were discriminated by using this detection set combined with chemometrics method. The effect of length of liquid core optical fiber on laser induced fluorescence spectrum was explored, and the differences between the spectra of different edible oils were analyzed. The fluorescence spectra of 320 samples covering 8 types of edible oil were measured in 1 meter liquid core optical fiber. Principal component analysis was used in fluorescence data dimensionality reduction process. Partial least squares discriminant analysis (PLS-DA) method was used to develop the identification model to distinguish edible oil species. The results showed that the oil fluorescence intensity is greatly enhanced when liquid core optical fiber was used. With the increase of liquid core optical fiber length, the peaks of laser induced edible oil fluorescence spectra increased and the fluorescence spectra will produce red shift. The red shift tended to a constant value when the fiber length was more than 80 cm. The fluorescence spectra of different edible oils were quite different, its can be used to distinguish different types of edible oil. Principal component scores chart were get using PC1 and PC2 of edible oils fluorescence data which result in a trend of certain gather of same type of edible oil. The recognition rates of PLS-DA model for the calibration set and prediction set were both 100%. The study shows that the developed device in this study has high accuracy for identifying the edible oil species..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3202 (2016)
Difference of Nonlinear Degree between Healthy and Diabetic Rat Erythocyte Fluorescence Spectrum
WANG Lei, LIU Gui-dong, LIU Li, LIU Yu-jie, LOU Hong-jun, QI Chao, XIAO Hong-bin, and CHI Wen-cheng
Diabetes mellitus is one kind of chronic diseases which seriously threaten human health. It is very important to diagnose in the early stage. With the development of diabetes, the structure and function of erythrocyte in the blood will change. So the peak position and peak height of erythrocyte fluorescence spectrum arDiabetes mellitus is one kind of chronic diseases which seriously threaten human health. It is very important to diagnose in the early stage. With the development of diabetes, the structure and function of erythrocyte in the blood will change. So the peak position and peak height of erythrocyte fluorescence spectrum are different. These differences can be used to determine the status of diabetes. In the selection of the difference of spectral signal as the feature vector, the nonlinear degree of fluorescence spectrum can be used as the feature vector. In order to describe the nonlinearity of the fluorescence spectrum signal, the nonlinear degree of the signal is described with the delay vector variance (DVV) method. By using the method of iterative amplitude adjusted Fourier transformation (IAAFT) to generate surrogate data of raw data, the nonlinear characteristic of the raw data is determined by comparing the DVV of the original data and the surrogate data. The variance of the original data is the horizontal coordinates, and the variance of the surrogate data is the longitudinal coordinates, thus the DVV scatter plot is drawn. The DVV scatter plot of healthy rat erythrocyte fluorescence spectrum is almost coincident with its diagonal, which means the nonlinear degree of healthy rat erythrocyte fluorescence spectrum is lower. The DVV scatter plot of diabetic rat erythrocyte fluorescence spectrum deviates from its diagonal, which means the nonlinear degree of healthy rat erythrocyte fluorescence spectrum is higher, also the corresponding amino acid spectrum nonlinearity is deeper. Therefore, it is proposed that the nonlinear difference between the healthy and diabetic fluorescence spectrum can be used as a feature of early diabetes diagnosis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3207 (2016)
A Study on Synthesis of CaAl12O19∶xMn4+ Red Phosphor with Combustion Method
FENG Ying, TONG Yi-ping, and LI Wen-wei
The CaAl12O19∶xMn4+ phosphor was rapidly synthesized at low temperatures with combustion method with urea as combustion agent. The influence of calcination temperature and time, the doping amount of Mn4+ ions, the molar ratio of combustion agent to CaAl12O19, on luminous intensity of fluorescent powder were examined wiThe CaAl12O19∶xMn4+ phosphor was rapidly synthesized at low temperatures with combustion method with urea as combustion agent. The influence of calcination temperature and time, the doping amount of Mn4+ ions, the molar ratio of combustion agent to CaAl12O19, on luminous intensity of fluorescent powder were examined with orthogonal analytical method. The optimum conditions for preparing phosphors are: sintering temperature 1 200 ℃, the amount of Mn4+ 0.02, the molar ratio of combustion agent to CaAl12O19 50∶1, and sintering time 5 hrs. The corresponding luminous intensity of this powder was 95.8, which is the largest. The phosphor shows a strong red luminescence at the 643 and 656 nm due to the 2E—4A2 transition of the Mn4+. The maximum excitation peak was at 470 nm due to the 4A2—4T2 transition of Mn4+ ligand field. The 470 nm excitation peak was matched with the 465 nm emission of the LED chips..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3211 (2016)
Rapid and Noninvasive Detection of Skin Cholesterol with Diffuse Reflectance Spectroscopy Technology
HOU Hua-yi, DONG Mei-li, WANG Yi-kun, ZHU Ling, MA Zu-chang, and LIU Yong
Due to the urgent need for noninvasive detection of skin cholesterol, a portable, intelligent and real-time skin diffuse reflectance spectroscopy measurement system was designed based on a micro-spectrometer. Digitonin-horseradish peroxidase copolymer solution was prepared. According to the properties digitonin binds tDue to the urgent need for noninvasive detection of skin cholesterol, a portable, intelligent and real-time skin diffuse reflectance spectroscopy measurement system was designed based on a micro-spectrometer. Digitonin-horseradish peroxidase copolymer solution was prepared. According to the properties digitonin binds to the hydroxy of cholesterol molecular specifically and the horseradish peroxidase reacts with TMB color solution (the main component is 3,3’,5,5’-tetramethylbenzidine ) a color change was produced, by which the skin cholesterol was identified and instructed with high sensitivity and high specificity, and the concentration of skin cholesterol was quantified by measuring the degree of color change. In order to validate the feasibility of this method, pig skin which is similar to human skin was taken as the experimental subject, and cholesterol samples of gradient concentration were achieved through the extraction. After that the spectroscopy measurement system was adopted to detect the cholesterol concentration. The experiment result showed that, relative diffuse reflectance can distinguish the cholesterol samples with different concentrations, and the diffuse reflectance intensity factor can quantity the concentrations of cholesterol at characteristic wavelengths (442, 450 and 463 nm) and characteristic wavelength band of 442~500 nm. Linear fitting curves were obtained with the determination coefficient R2 were 0.960, 0.959, 0.958 and 0.958, respectively. The study has shown that, using diffuse reflectance spectroscopy technology can realize noninvasive rapid detection of skin cholesterol, and applying it to the risk assessment of atherosclerotic diseases would contribute to the prevention and control of such diseases significantly..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3215 (2016)
A Mechanism Study of Reflectance Spectroscopy for Predicting Soil Total Nitrogen
ZHENG Guang-hui, JIAO Cai-xia, SHANG Gang, and XIONG Jun-feng
Reflectance spectroscopy has been widely used for predicting soil properties due to its rapidity and convenience. In past decades, the application of soil spectroscopy on soil science studies has increased exponentially. The total nitrogen (TN) content in soil is an important index for soil fertility and the rapid predReflectance spectroscopy has been widely used for predicting soil properties due to its rapidity and convenience. In past decades, the application of soil spectroscopy on soil science studies has increased exponentially. The total nitrogen (TN) content in soil is an important index for soil fertility and the rapid prediction of TN content with spectroscopy serves an important function in precision agriculture. However, whether the TN content in soil is predicted through its relationship with soil organic carbon (SOC) or on its specific absorption is still debatable. The objective of this study was to explore the mechanism of reflectance spectroscopy for predicting TN in soils. Soils used for calibration were sampled from coastal soil in the north of Jiangsu province. Partial least squares regression (PLSR) analysis was used for the calibration datasets with different TN content when the sample number is the same in every dataset. In order to explore the mechanism of reflectance spectroscopy for predicting total nitrogen in soil, the changes of model accuracies and the correlation of TN and SOC were analyzed. The results indicated that the contents of TN and SOC in soil were relatively lower because the soil was derived from coastal sediments in the past 1 000 years and formed during cultivation. There was strong correlation between TN and SOC (R=0.98). The prediction accuracy of TN increased at first and then decreased slightly with the increase of mean, standard deviation of TN content. Meanwhile, the changes of prediction accuracy comply well with coefficients of variation. In conclusion, when the TN content is relatively low (mean TN<0.27 g·kg-1), the correlation coefficient between TN and SOC was moderately-high and TN was predicted on the basis of N absorbers. When the TN content is relatively high (mean TN>0.29 g·kg-1), strong correlation coefficients were obtained for TN and SOC and the model accuracy of SOC were better than TN. The effect of SOC to spectroscopy enhanced with the increase of SOC content, which masked the spectral features of N. Therefore, TN was predicted through the correlation with SOC when the TN content is high. This study revealed the mechanism of reflectance spectroscopy for predicting TN in soil and it could provide a theoretical basis for predicting soil TN content rapidly using reflectance spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3222 (2016)
Simulation Analysis & Experimental Study of the Effects of Satellite Vibration Frequency and Amplitude on Hyperspectral Image
NAN Yi-bing, and NI Guo-qiang
In the imaging process of satellite-based pushbroom hyperspectral imager, attitude motions of satellite platform, represented by vibrations, will cause aliasing of the object information comes from different sub-areas of the detector, leading to degradation of hyperspectral image quality. In order to suppress and correIn the imaging process of satellite-based pushbroom hyperspectral imager, attitude motions of satellite platform, represented by vibrations, will cause aliasing of the object information comes from different sub-areas of the detector, leading to degradation of hyperspectral image quality. In order to suppress and correct the imaging errors caused by satellite vibrations more effectively, spatial and spectral degradation mechanisms of typical dispersive pushbroom imaging spectrometer caused by satellite vibration are studied in this paper, including theoretical simulation and experimental study. With the analysis of spectral mixing process during exposure, the relationship between spectrum of ground object and satellite attitude is obtained, and a degradation model of pushbroom spectral imaging is presented. The effects of different attitudes of vibration are considered in the degradation model. Mean mixing ratios of each pixel are easy to calculate with a universal coefficient matrix, as long as the satellite attitude parameters of each moment are known. Then the simulation degraded spectral image data cube is achieved. The common expression of mean mixing ration is derived in detail. More important, the effects of vibration amplitude and frequency are quantitative analyzed separately. Degraded simulation and ground simulation experiments are carried out based on real hyperspectral data cubes, then the quality of the cubes before and after degradation are evaluated. Results show that simulation is in good agreement with reality. Mean mixing ratio can reflect the degradation extent of hyperspectral data directly. The satellite vibrations bring about spatial quality deteriorate of hyperspectral image, and lead to the aliasing of spectrum comes from different ground object. The degradation extent of hyperspectral data is determined mainly by vibration amplitude. The influence of frequency is limited..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3226 (2016)
Absorption Characteristics and Environmental Significance of Dissolved Organic Matter in Lake Dongping
YAO Xin, SUN Jiang-ling, DONG Jie, LIU Xue-li, LIU Yu-ping, and FANG Xiao-xiao
As an important water source in Shandong Province, Lake Dongping is one of the most important inland lakes to South-to-North Water Diversion East Route Project. We tried to provide the basis for real-time monitoring of water quality mutation by using CDOM absorption characteristics. The average values of CDOM absorptioAs an important water source in Shandong Province, Lake Dongping is one of the most important inland lakes to South-to-North Water Diversion East Route Project. We tried to provide the basis for real-time monitoring of water quality mutation by using CDOM absorption characteristics. The average values of CDOM absorption coefficients ［a(280), a(350), a(440)］ were (12.90±1.17), (3.11±0.40) and (0.65±0.09) m-1. a(440) had linear relationships with total nitrogen (p<0.01), total phosphorus (p<0.001), dissolved organic carbon (p<0.001), chemical oxygen demand (p<0.001), Chlorophyll a (p<0.001), which can be used to estimate the water quality parameters. The results showed that CDOM absorption coefficient reflects the nutritional status of Lake Dongping, which is close to eutrophication level. There was an obvious decrease of CDOM absorption coefficients from river mouth of Dawen River to lake center and then to the outlets of lake. This illustrated that terrestrial input is the main source of nutrients and pollutants in Lake Dongping..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3232 (2016)
Measuring the Moisture Content in Maize Kernel Based on Hyperspctral Image of Embryo Region
TIAN Xi, HUANG Wen-qian, LI Jiang-bo, FAN Shu-xiang, and ZHANG Bao-hua
Maize is among the most important economic corps in China while moisture content is a critical parameterin the process of storage and breeding. To measure the moisture content in maize kernel, a near-infrared hyperspectral imaging system has been built to acquire reflectance images from maize kernel samples in the specMaize is among the most important economic corps in China while moisture content is a critical parameterin the process of storage and breeding. To measure the moisture content in maize kernel, a near-infrared hyperspectral imaging system has been built to acquire reflectance images from maize kernel samples in the spectral region between 1 000 and 2 500 nm. Near-infrared hyperspectral information of full surface and embryo of maize kernel were firstly extracted based on band ratio coupled with a simple thresholding method and the spectra analysis between moisture content in maize kernel and embryo was performed. The characteristic bands were then selected with the help of Competitive Adaptive Reweighted Sampling (CARS), Genetic Algorithm (GA) and Successive Projection Algorithm (SPA). Finally, these selected variables were used as the inputs to build Partial Least Square (PLS) models for determining the moisture content of maize kernel. In this study, a significant relation, which the spectral reflectance decreases as moisture content increase, between moisture content and spectral of embryo in maize kernel was observed. For the investigated independent test samples, all the proposed regression models, namely CARS-PLS, GA-PLS and SPA-PLS, achieved a good performance by using the information of embryo region. The correlation coefficient (Rp) and Root Mean Squared Error of Prediction (RMSEP) and number of characteristic wavelength for the prediction set were 0.931 2, 0.315 3, 9 and 0.917 6, 0.336 9, 14 and 0.922 7, 0.336 6, 16 for CARS-PLS, GA-PLS and SPA-PLS models, respectively. And, compared with models obtained by full surface spectral information, less characteristic wavelengths is used for development of CARS-PLS, GA-PLS and SPA-PLS models, while similar results were obtained. Comprehensively analyzing to both model accuracy and model complexity, SPA-PLS model by using embryo region information achieved the best result. Wavelengths at 1 197, 1 322 and 1 495 nm were applied to extracted the information of embryo region, and the bands at 1 322, 1 342, 1 367, 1 949, 2 070 and 2 496 nm were used to establish the SPA-PLS model. These results demonstrated that near-infrared hyperspectral information from embryo region is more effective for determination of moisture nondestructive in maize kernel..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3237 (2016)
Catalytic Liquefaction of Corn Stalk under Atomosphere Prssure and the Analysis of Liquefaction Products
ZHANG Juan, LIU Hai-tang, LIU Zhong, and JIANG Qi-fan
With concentrated phosphoric acid as catalyst and various organic solvents as liquefying agents, corn stalk powder was liquefied into bio-oil in an autoclave, under the condition of 170 ℃. Analysis was conducted to throw light on the liquefying effects of three different agents; they are glycerol triacetate with ethyleWith concentrated phosphoric acid as catalyst and various organic solvents as liquefying agents, corn stalk powder was liquefied into bio-oil in an autoclave, under the condition of 170 ℃. Analysis was conducted to throw light on the liquefying effects of three different agents; they are glycerol triacetate with ethylene carbonate, glycerol with ethylene carbonate and polyethylene glycol with ethylene carbonate(6∶1 ω/ω), and the properties of the biomass liquefaction oil products. FT-IR was applied to examine raw material and residues, whose chemical compositions were further analyzed with the use of GC-MS. The results of experiments indicated that the liquefaction yield of polyethylene glycol was 97.84%, the yield of glycerol triacetate was 80.20%, the yield of glycerol were36.97%. FT-IR analysis showed that the functional groups of cellulose, hemicelluloses and lignin was disappeared and liquefaction is best when polyethylene glycol with ethylene carbonate was used as the liquefaction agent. GC-MS analysis showed that the oil composition produced in this way is complex, contains organic acids and ketones, alcohols and ethers, aromatic, sugars and esters compounds..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3243 (2016)
Analysis of the Effect of Moisture on Soil Organic Matter Determination and Anti-Moisture Interference Model Building Based on Vis-NIR
WANG Shi-fang, CHENG Xu, and SONG Hai-yan
Soil moisture shows a strong absorption for spectroscopy while soil organic matter and moisture have identical absorption bands. Therefore, the soil moisture causes interference to soil organic matter detection. The study made the following works: firstly, different soil organic matter dynamic spectrums under differentSoil moisture shows a strong absorption for spectroscopy while soil organic matter and moisture have identical absorption bands. Therefore, the soil moisture causes interference to soil organic matter detection. The study made the following works: firstly, different soil organic matter dynamic spectrums under different moisture content were acquired with visible near-infrared spectroscopy; secondly, different organic matter content features under the same moisture content were analyzed with two-dimensional synchronization correlation spectroscopy. When the soil moisture is 0%, around 600 and 1 660 nm which characterize soil organic matter band appear strong autocorrelation peaks. With moisture content increasing, around 600 and 1 660 nm band disappear and around 1 931, 2 200 and 1 480 nm band appear strong autocorrelation peaks in the near-infrared region. Soil moisture covers information bands which characterize soil organic matter and affects soil organic matter detection; thirdly, the maximum moisture content samples approximately in the filed participated modeling to eliminate the effect of moisture on soil organic matter detection and improve the model prediction accuracy. The anti-moisture interference prediction model which used 550~650 and 1 610~1 710 nm wavelengths by PLS (Partial Least Squares) quantitative analysis method was established to predicate the soil organic matter content under different moisture content. The results are as follows: predicted correlation coefficient, SEP and RMSEP is 0.954, 0.744 and 0.844 respectively. Predicted effect improves significantly. It is that the method can reduce the effect of moisture on soil organic matter detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3249 (2016)
Hyperspectral Study of Estimating Nitrification Microorganism in Wetland Soils
WEI Ya-xing, and WANG Li-wen
Nitrogen cycle is an important process in the circle of soil ecosystem elements, and nitrification has significant effect on soil nitrogen cycling. The main completer of nitrification is nitrification microbial communities. Soil microorganisms are vital components of wetland ecosystem. They can indicate the variations Nitrogen cycle is an important process in the circle of soil ecosystem elements, and nitrification has significant effect on soil nitrogen cycling. The main completer of nitrification is nitrification microbial communities. Soil microorganisms are vital components of wetland ecosystem. They can indicate the variations of wetland ecological environment, and this helps us to have the correct understanding of nitrogen cycle and pollution purification function in wetland ecosystem. This paper tries to study nitrification microbial communities in wetland soils from the perspective of hyperspectral remote sensing technology, based on the monitoring mechanisms of soil nitrogen spectrum. The study explores hyperspectral estimation techniques for nitrification microbial communities in wetland soils, and it can provide a new technical approach to estimate the temporal and spatial distribution of nitrification microbial communities. The study adopted most probable number method (MPN) to count the numbers of ammonia oxidizing bacteria and nitrite oxidizing bacteria respectively, which were main completers of two independent stages in nitrification. And the total results of both count measurements were used as the values of soil nitrification microorganisms for each sampling area. The estimation models of nitrification microorganism and total nitrogen in wetland soils were developed respectively using spectral transformation techniques, such as log-transformed spectra (LR), first derivative (FD), second derivative (SD), continuum removal (CR) and band depth (BD), and modeling methods, such as stepwise multiple linear regression (SMLR) and partial least-squares regression (PLSR) based on the bootstrap technology. The results indicated that the selected estimation bands of nitrification microorganism and total nitrogen were close (especially for original spectral data (R) and SD spectra) when the modeling method of bootstrap SMLR was used. Compared to the bootstrap SMLR, the bootstrap PLSR achieved higher accuracies for estimating nitrification microorganism and total nitrogen in wetland soils. The spectral transformation technique of SD combined with the modeling method of bootstrap PLSR yielded the highest estimation accuracy to predict nitrification microorganism in wetland soils. The CR spectral data combined with bootstrap PLSR produced the highest estimation accuracy to predict total nitrogen content in wetland soils..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3254 (2016)
The Comparison of Spectral Classification Based on DBN, BP Neural Network and SVM
LI Jun-feng, WANG Yue-le, HU Sheng, and HE Hui-ling
The stellar classification was an important research field for understanding the formation and evolution of stars and galaxies. With large sky surveys and its massive data, the speed and accuracy of the celestial automatic classification was very important. The depth confidence neural network (DBN), support vector machThe stellar classification was an important research field for understanding the formation and evolution of stars and galaxies. With large sky surveys and its massive data, the speed and accuracy of the celestial automatic classification was very important. The depth confidence neural network (DBN), support vector machines (SVM) and BP neural networks used in the star classification were compared in this paper. And the applicability of star classification with these three methods was analyzed. First, K, F stars are classified according to the depth of confidence neural network and BP neural network and support vector machine.Then the K1, K3, K5 sub-type and F2, F5, F9 sub-type were separately identified. Finally, the data which did not belong to the k sub-type were excluded by a secondary classification model based on SVM support vector machine . The results shows that: the depth of belief networks is better for K, F-type star classification, but it is poor for K, F sub-type classification results; The recognition rate of SVM is high for the K, F-type stars and the classification effects of this method is better for K, F-type stars than the corresponding sub-type stars by comparison; The recognition rate of BP neural network is ordinary general for K, F-type stars and their sub-types. The experiment showed that the accuracy of excluding non-k-sub-type data can be up to 100% which indicates that the unknown spectral data can be screened and classified with SVM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3261 (2016)
Thickness Calculation of Silicon Dioxide Nano-Film Based on GIXRR Reflectivity Curve
MA Yi-bo, WANG Mei-ling, WANG Hai, YUAN Pei, FAN Yan, XING Hua-chao, and GAO Si-tian
To obtain nanometer thin film thickness fastly and accurately, a formula of linear fitting method based on the periodic Kiessig fringes for thickness determination is applied, and a series of SiO2 nanometer films on Si substrate with the film thickness ranging from 10 to 120 nm have been calculated with the formula. ThTo obtain nanometer thin film thickness fastly and accurately, a formula of linear fitting method based on the periodic Kiessig fringes for thickness determination is applied, and a series of SiO2 nanometer films on Si substrate with the film thickness ranging from 10 to 120 nm have been calculated with the formula. These samples are prepared with thermal atomic layer deposition (T-ALD) process and film thickness is measured with grazing incidence X-ray reflection (GIXRR) technique, in addition, the linear fitting procedure and several influencing factors among it are studied, all of the work is based on the reflectivity curve from GIXRR experiment. While at the same time, another fitting method based on a soft named Global Fit2.0 is brought into this study to compare the two obtained thicknesses from two kinds of analysis methods. In the end a novel method for film thickness determination-empirical curve is presented. The results show that: during the linear fitting process, the peak position series have a main effect on thickness determination, thickness will increase when the peak position adds up; Besides, any peak’s corresponding reflection angle also has a significant effect on the thickness determination, it is expressed in the form of interference fringe period, thickness will decrease while the interference fringe period increases, however, the errors from either peak series or fringe period can be further weakened with trial and error method, calibration procedure of critical angle and interference fringe period individually. Choosing the same sample with random thickness, no matter using the linear fitting and soft fitting method, the two gained film thicknesses are consistent and the thickness deviation is less than 0.1 nm, which illustrates the accuracy of linear fitting method for thickness determination. An empirical relationship between film thickness and interference fringe period is then put forward on the foundation of the accurate thickness determination, according this curve, the target film thickness is directly got by putting an interference fringe period in the empirical curve. This novel method not only avoids the messy procedure of choosing peak position series or their corresponding angles during linear fitting process, but also avoids the complex task of building a correct structure for soft fitting process; it is of great significance in confirming thin film thickness with quick speed and high accuracy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3265 (2016)
Analyzing Spectral Characteristics of Water Involving In-Situ Multiangle Polarized Reflectance and Extraction of Water-Leaving Radiance
SHEN Qian, LI Jun-sheng, ZHANG Bing, WU Yan-hong, ZOU Lei, and WU Tai-xia
Polarization is defined as an asymmetry in the direction of vibration with respect to the direction of light propagation. Polarization information is an important component to remote sensed data, which comprises spatial, spectral, and radiation information. In optical remote sensing, polarization information supplementPolarization is defined as an asymmetry in the direction of vibration with respect to the direction of light propagation. Polarization information is an important component to remote sensed data, which comprises spatial, spectral, and radiation information. In optical remote sensing, polarization information supplements spectral information. Polarization-based remote sensing has a significant application potential for analyzing the spectral characteristics of water bodies, wherein a very important technique is eliminating the mirror reflection caused by skylight on the water surface and extracting water-leaving radiance that carry the constituent information. The incident sunlight on the surface of water either reflects or scatters owing to the existence of particles in water, which results in water-leaving signals with strong polarization characteristics. The ongoing experiments on remote sensing involve water polarization cover either clean ocean waters under natural light or indoor simulations of water under artificial light; however, turbid inland waters under natural light have rarely been investigated. Through the combination of a field spectroradiometer and a Thompson polarizing prism, this study obtained in-situ measurements of the spectral polarization reflectance over inland waters under natural light conditions. Using the obtained multiangle polarized reflectance spectra, the polarization spectral characteristics of water under multiangle viewing conditions were quantitatively analyzed, and the water-leaving radiance was achieved by eliminating skylight reflection. When observing water bodies at an azimuth of 135° and a zenith of 53°, the measurement of polarization to eliminate skylight reflection had better elimination efficiency than at other viewing angles, and this observation angle was recommended for conducting spectral polarized above-water observations. Compared with the traditional methods including non-polarized above-water measurements, the proposed method is less prone to being affected by changes in weather conditions, and it can extract water-leaving radiance more accurately..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3269 (2016)
The Spectral Prediction of Original Primary Pigment Based on Constrained Non-Negative Matrix Factorization
HE Song-hua, CHEN Qiao, and DUAN Jiang
With direct prediction in the spectral reflectance space with principal component analysis, the numbers of eigenvectors will surpass the numbers of real primary pigments while the eigenvectors and the corresponding coefficients have negative value, which can not directly presented original primary pigment spectral charWith direct prediction in the spectral reflectance space with principal component analysis, the numbers of eigenvectors will surpass the numbers of real primary pigments while the eigenvectors and the corresponding coefficients have negative value, which can not directly presented original primary pigment spectral characteristics and corresponding concentration. We proposed an innovative spectral prediction method in which a complete linear spectral space was created according to optical properties of originals pigment. A constrained non-negative matrix factorization algorithm to predict the numbers and spectral curve shapes of real primary pigments was used in the space. So, this paper designed an overall research plan and implementation process about spectral prediction method firstly, and studied how to select and establish a spectral linear space which was conformed to optical properties of originals; taking transparent pigments as example, and spectra constrained non-negative matrix factorization (SCNMF) algorithm was established to predict primary pigment spectra based on basic non-negative matrix factorization algorithm (BNMF). Aiming at realizing multiple optimal solution of BNMF and improving the prediction accuracy as well as make the matrix decomposition results to be clearly physically meaningful; the proposed SCNMF needs to satisfy four constraints: non negative constraint, additive constraint, smoothness constraint and sparseness constraint. The objective function and iterative algorithm to meet four constraints were set up. The prediction results show that the proposed method can realize accurate prediction of original primary pigments’ numbers and spectra effectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3274 (2016)
Optimization of Maximum Light Use Efficiency in Inner Mongolian Steppe
BAO Gang, XIN Xiao-ping, BAO Yu-hai, WANG Mu-lan, YUAN Zhi-hui, and Wulantuya
For the case that the value of the maximum light use efficiency (MLUE) is not optimized for different steppes, we simulated the MLUE for meadow steppe, typical steppe and desert steppe in Inner Mongolia based on the field observed NPP and CASA ecosystem model, and analyzed the spatial and temporal pattern of the LUE anFor the case that the value of the maximum light use efficiency (MLUE) is not optimized for different steppes, we simulated the MLUE for meadow steppe, typical steppe and desert steppe in Inner Mongolia based on the field observed NPP and CASA ecosystem model, and analyzed the spatial and temporal pattern of the LUE and net primary productivity (NPP) in Inner Mongolia. The result indicate that the MLUE is optimized to be 0.654, 0.553 and 0.511 gC·MJ-1 for meadow steppe, typical steppe and desert steppe in Inner Mongolia, respectively, with an average of 0.573 gC·MJ-1. Compared to the result that used same value of 0.541 gC·MJ-1 for MLUE, the correlation coefficient and relative mean square error was improved 0.024 and 2.62 gC·(m2·month-1)-1, respectively after optimization. Affected by the hydrothermal condition and distribution of grassland types, the LUE and NPP in Inner Mongolia decreased from northeast to southwest, and showed one crest shape. However, the maximum value of LUE and NPP was appeared in August and July. This difference could be attributed to the difference in the maximum value between absorbed photosynthetically active radiation and LUE. The LUE and NPP decreased by meadow steppe, typical steppe and desert steppe..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3280 (2016)
Study on Absorption Spectra of Lutein Aggregate with Experimental Analysis and Theoretical Calculation
LU Li-ping, LI Ming, LIU Gui-ling, WEI Liang-shu, and WU Fang
Compared with the monomer, aggregate exhibits unique features such as electron and energy transfer which can be understood with the study of absorption spectra. In the experimental the absorption spectra of lutein monomer in ethanol solution and aggregate in 1∶1 aqueous ethanol solution are detected by utilizing UV-lViCompared with the monomer, aggregate exhibits unique features such as electron and energy transfer which can be understood with the study of absorption spectra. In the experimental the absorption spectra of lutein monomer in ethanol solution and aggregate in 1∶1 aqueous ethanol solution are detected by utilizing UV-lVis spectrophotometer. The vibration structure of excited state of lutein monomer is obtained with Gauss decomposition of the absorption spectra. Theoretically, the molecular parameters of excitation energy, vibration frequency of characteristic mode, Huang-Phys factor are calculated by means of simulation of the monomer absorption spectra described by temporal correlation function and Frenkel exciton model. The spectral calculation of the lutein aggregate is conducted by using these parameters and then the factors of the spectral changes affected by the aggregate structure are analyzed. Some conclusions are drawn from the analysis: (1) The absorption peak position of the aggregate is determined mainly by intermolecular interaction. The calculation shows that the interaction is about 2 000 cm-1 according 77 nm blue shift of absorption spectra from experiment result. (2) With the increase of molecular number of the aggregate the half-width of the absorption spectra decreases and the peak position blue shift slightly due to enhanced cooperation effect. (3) Disorder degree from environment has great influence on half-width for the greater disorder degree the larger half-width. The results of this paper will provide a theoretical reference for the further study of lutein aggregate function in biological and materials systems..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3287 (2016)
Effect of Acid Elution on the Surface Structure Characteristics and Spectral Characteristics of Biochars
WANG Yue-ying, and L Yi-zhong
Biochar often refers to a carbon-rich product obtained by pyrolyzing biomass at relatively low temperatures (<700 ℃). The increasing interest in the applications of biochar in soil amendment and environmental contaminant reduction has spurred many studies in recent years. Due to the high content of ash in biochar, tBiochar often refers to a carbon-rich product obtained by pyrolyzing biomass at relatively low temperatures (<700 ℃). The increasing interest in the applications of biochar in soil amendment and environmental contaminant reduction has spurred many studies in recent years. Due to the high content of ash in biochar, the adsorption capacity of bichar is limited. The ash of biochar formed during pyrolysis has great influence on the structure characteristics and spectral characteristics of biochar. The ash of biochar is expected to enchance their efficacy and minimize their influence. For this purpose, the corn straw biochar made at two different temperatures (400 and 600 ℃) was used to study the effect on the structure characteristics of biochars under the acid elution. The samples were characterized with element analysis, Brunaner-Emmett-Teller-N2 surface areas, pore size distributions and micro infrared for structure analysis in this study. The result indicate that: the elution solvent could remove the by-products and improve the adsorptive capacity of biochars. (1)After acid elution, the carbon content, hydrophobicity and the aromatic functional group content were increased; the polarity of biochar was decreased. (2) After acid treated, the specific surface area of the biochars was significantly increased, the increment of two biochars was 3.46 times and 6.75 times; the pore volume and the mesoporous quantity were also enhanced. (3) After acid elution, the infrared analysis is similar, but the content of key functional groups was different significantly. The result of infrared analysis showed that, several absorbance peaks were decrease at 3 398~3 447, 2 924~3 056, 1 378~1 439 cm-1, and the acid treated can make the content of aliphatic chain char and hydroxyl reduce. (4) Biochar with low polarity and high aromaticity displayed a superior 2,4- dichlorophenoxyacetic acid adsorption capacity. Acid elution made the surface of biochar exposed more organic surface and porosity and it is one of the most important factors for the adsorption of biochar. The date with elemental analyzer, BET, FTIR techniques and batch experiment allowed us to develop a better understanding of evolution of biochar properties during the acid elution and these results have significant implications for using biochar as a soil additive for soil pollution..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3292 (2016)
Research on Heat Transfer Characteristics in Oil Pool Fire Based on Spectral Analysis
LIU Hong-tao, CHEN Zhi-li, YANG Yi, YIN Wen-qi, and LIU Qiang
The inner part of the oil pool flame could be divided into different combustion areas, and there have been a limited number of researches on the heat transfer characteristics within oil pool fire. Due to the lack of adequate researches on the characteristics of heat transfer in oil pool flame, this paper carries out anThe inner part of the oil pool flame could be divided into different combustion areas, and there have been a limited number of researches on the heat transfer characteristics within oil pool fire. Due to the lack of adequate researches on the characteristics of heat transfer in oil pool flame, this paper carries out an analytical study to pool flame spectrums of 92# gasoline, 95# gasoline and lube by establishing flame infrared testing system. Spectral information about different combustion regions of oil pool fire is collected. The results show that three kinds of oil pool fire have similar spectral characteristics, with several characteristics emission bands of such combustion products as CO2, H2O and carbon black particles and that 3.4 μm C—H stretching vibration peak is obvious; the main spectral characteristics of smoke zone is high temperature CO2 emission peak at the band range of 4～4.5μm, the heat exchange of flame and air is violent; the temperature changes unstably, and flame pulse frequency is high; spectral characteristics in the intermittent area is high temperature CO2 emission peak at 4～4.5 μm; and flame pulse frequency in intermittent zone is relatively lower compared with that in the smoke zone; compared with that in the flue gas zone and intermittent zone, the combustion in continuous zone is more stable, the spectral characteristics of the region is obvious, and carbon black particle emission intensity is high at 2.5～3 μm, and C—H stretching vibration emission peak shows itself at 3.4 μm, which showed that the characteristic peak oil pool flame spectrum at 3.4 μm is caused by high temperature oil vapor steam. Spectral characteristics analysis of the oil pool flame in different combustion areas shows that the heat transfer is absorbed by the fuel rich layer on the surface of the oil pool flame, which leads to the change in the energy level of the oil vapor near 3.4 μm. The calculation of the emission spectrum intensity of oil pool flame in different combustion areas shows that the intensity in flame continuous zone is the largest, followed by the intermittent zone, that the connection between the flame smoke zone and the air is strong, and that the emission spectrum intensity is the lowest. The results in this study provide a reference for the modification of flame oil heat transfer model..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3297 (2016)
Adaptability of Different Nebulizer Systems to Different Silicon Chemical Forms for Gasoline in Inductively Coupled Plasma Optical Emission Spectrometry
ZHAO Yan, CHEN Xiao-yan, XU Dong-yu, ZHANG Shi-yuan, and LIAO Jia
Silicon is not a natural component of gasoline but it can cause silica deposition in vehicle combustion system which may lead to severe engine failure. Silicon is present in gasoline in different chemical forms. The analysis of oil products by directly measuring under organic phase through inductively coupled plasma opSilicon is not a natural component of gasoline but it can cause silica deposition in vehicle combustion system which may lead to severe engine failure. Silicon is present in gasoline in different chemical forms. The analysis of oil products by directly measuring under organic phase through inductively coupled plasma optical emission spectrometry (ICP-OES) is becoming a widely accepted approach as it is found to be simple and fast. The work focused on the influence of the sample nebulizer systems to different silicon chemical forms by ICP-OES. For a sample introduction system consisting of micronebulizer coupled to a cyclonic spray chamber, the results indicated that the ICP-OES signals depended strongly on the silicon chemical forms, and the higher emission intensities have been attributed to the compound volatility. The variability of the signals induced by the different silicon compounds was less significant for the same nebulizer system with a temperature control device. Nevertheless, the interferences were not effectively mitigated. Nevertheless, direct injection high efficiency nebulizer (DIHEN) introduced in the present work can effectively mitigate the interferences of different silicon chemical forms, is suitable for the determination of silicon in gasoline. The quantitative method with the potential DIHEN nebulizer system showed good linearity and the recoveries ranged from 92.8%～108.7%, the limit of detection was 0.05 mg·kg-1. The relative standard deviation (RSD) was between 1.05% and 4.63%. Compared with the microwavedigestion method, the proposed method was found to be highly simple, rapid, sensitive and accurate, which has foreseen a promising application for silicon determination in gasoline..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3303 (2016)
Element Geochemistry of Lake Sediments from L07-10 in the “Great Ear” Area of Lop Nur and Its Significance for Climate Variation Change with ICP-OES
ZHU Xin-ping, JIANG Ping-an, ZHANG Liang-hui, LI Bao-guo, SHENG Jian-dong, and WU Hong-qi
Spectral analysis techniques were applied to geochemical element analysis to provide additional environmental data about evolution of salt lakes and climate change. The elements composition of lake sediments from L07-10 in the “Great Ear” Area of Lop Nur was analyzedby using Inductively Coupled Plasma Optical Emission Spectral analysis techniques were applied to geochemical element analysis to provide additional environmental data about evolution of salt lakes and climate change. The elements composition of lake sediments from L07-10 in the “Great Ear” Area of Lop Nur was analyzedby using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES )and from 14 C carbon dating by using the EN accelerator mass spectrometry (AMS).This paper estimated the climate change in this region since 16.34 ka BP. Results demonstrate that the geochemical characteristics of major elements at all sediment levels can indicate environmental change sensitivity, and element composition is more sensitive to climate change. Overall, climate succession since 16.34 ka BP had been: warm-wet, warm-dry, cold-wet and warm-dry. From 8.09~6.34 ka BP, the climate obviously heated up and was warmer and drier, which is consistent with global and regional climate change estimates from other studies. By about 2 ka BP, the climate becomes warmer and drier and the water carrying capacity of this lake was reduced..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3308 (2016)
Application of LA-ICP-AES to Distinguish the Different Turquoise Mines
XIAN Yi-heng, LI Yan-xiang, TAN Yu-chen, WANG Wei-lin, YANG Qi-huang, and CUI Jian-feng
Currently, the technological development of non-destructive analysis and micro-damage analysis of turquoise is fast. LA-ICP-AES, an almost non-destructive analysis, has multiple advantages. This paper attempts to use this analysis method to examine sample turquoise from five places of origin on Mount East Qinling, inclCurrently, the technological development of non-destructive analysis and micro-damage analysis of turquoise is fast. LA-ICP-AES, an almost non-destructive analysis, has multiple advantages. This paper attempts to use this analysis method to examine sample turquoise from five places of origin on Mount East Qinling, including ancient turquoise ore in Laziya, in order to attain its major element and microelement data. Then the paper uses PCA to analyze and study its chemical elements in a comparative way. Three main elements are gained through analysis, and their cumulative variance contribution rate has reached 84.96%. The former two main elements’ variance contribution rate is 72.289%. Therefore, the corresponding elements, including V2O5, NiO, B2O3, SrO, BaO, CaO, ZrO, MnO2, are the featured chemical elements of turquoise from different places of origin. Through comparative analysis and research on corresponding chemical elements, turquoise samples produced by different ores vary in terms of the content of some chemical element and chemical components. Two analysis methods combined together will basically realize the appreciation of turquoise in various places of origin. In addition, the research indicates that some chemical contents have positive or negative correlations. Such correlations can be regarded as features of producing area, and can also provide clues as to the cause of formation of turquoise ore. This study preliminarily indicates that LA-ICP-AES combined with PCA and comparative analysis of chemical composition and content has the function of distinguishing turquoise produced in different places of origin to a certain extent..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3313 (2016)
Optimization of ICP-AES and ICP-MS Techniques for the Determination of Major, Minor and Micro Elements in Lichens
ZHAO Liang-cheng, JIANG Yun-jun, GUO Xiu-ping, LI Xing, WANG Yi-dan, GUO Xiao-biao, LU Feng, and LIU Hua-jie
Lichens are one of the best materials for air quality biomonitoring, and they have been widely used in atmospheric element deposition monitoring in many regions. Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) are two efficient techniques widelLichens are one of the best materials for air quality biomonitoring, and they have been widely used in atmospheric element deposition monitoring in many regions. Inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) are two efficient techniques widely used in quantifying and quantifying plant elements. However, elemental levels in lichens from some regions in China are much higher than in other plants, and their variation is highly dependent on space, time, species and elements. Although atmospheric pollution monitoring is urgently needed in China in recent decades, little studies have been performed on biomonitoring in the country. Therefore, the methodological studies on the determination of lichen elements in China are needed to accelerate future biomonitoring studies with lichens. Two techniques such as ICP-MS and ICP-AES were used to determine elements in four reference materials, as GBW10014 (cabbage), GBW10015 (spinach), GBW10052 (green tea) and IAEA-336 (lichen), with an attempt to reveal the effects of different digestions, sampling size, spectral lines, isotopes and internal standard elements on measured results. ICP-AES after dry ashing-alkali fusion digestion and ICP-MS after microwave digestion were optimized for lichen element determination. In the optimized techniques, good linear relationship (r>0.999 0), low detection limit, high analytic accuracy and precision were obtained. The optimized techniques were applied to lichen samples collected from Taihang Mountains of China and Ardley Island of Antarctica. The results show that all lichen samples from Taihang Mountains were much higher in elemental concentration with the contribution of atmospheric deposition higher than those from Antarctica. These results suggest the applicability of the techniques in determining lichen elements, and provide evidences and technique supports for air pollution biomonitoring in China..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3320 (2016)
Determination of Trace Elements in the Melon of Indo-Pacific Humpback Dolphins (Sousa chinensis) with ICP-MS
ZHANG Ling-li, DING Yu-long, ZHANG Mei, GUI Duan, NING Xi, LI Jun, and WU Yu-ping
The Indo-Pacific humpback dolphins (Sousa chinensis) with long life-span are top predators in marine ecosystem -and they could accumulate heavy metals and persistent organic pollutants in their tissues, while the melon is a unique lipid-rich structure within the cetacean forehead that functions in the transmission of eThe Indo-Pacific humpback dolphins (Sousa chinensis) with long life-span are top predators in marine ecosystem -and they could accumulate heavy metals and persistent organic pollutants in their tissues, while the melon is a unique lipid-rich structure within the cetacean forehead that functions in the transmission of echolocation signals. To explore the baseline levels and the main characteristics of the components, the concentrations of vanadium (V), nickel (Ni), chromium (Cr), manganese (Mn), copper (Cu), arsenic (As), zinc (Zn), mercury (Hg), selenium (Se), cadmium (Cd) and lead (Pb) were determined in the melon of the Indo-Pacific humpback dolphins with inductively coupled plasma mass spectrometry (ICP-MS). The results showed that this method was quite suitable for the determination of trace elements in the melon of Indo-Pacific humpback dolphins with highly accuracy and precision, and the trace elements in melon existed individual differences. The average contents were in the order of Zn>As>Cu>Mn>Se>Hg>Cr>Ni>V>Pb>Cd. It is worth noting that the within (1.158 μg·g-1 ww), non-essential toxic trace element may cause toxic effect on the dolphins. Spearman correlation analysis showed positively significant correlations between As, Cd, Hg and body length, indicating that the concentrations of As, Cd, Hg may increase with age. Moreover, Cr and Ni were positively correlated (p<0.05), a significant negative correlation was observed between Mn and As (p<0.01), indicating that there are certain correlation among elements. In addition, the principal component analysis results showed that V, Mn, Ni, Se, Cu, Hg are the main characteristics of trace elements for melon. This study presents a reliable method for determination of the trace element analysis in cetacean melon, and this is the first study that reports the trance elements in the melon of the Indo-Pacific humpback dolphins in PRE that could provide reasonable and effective information for its conservation work..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3326 (2016)
In Situ Investigating of the Interaction of Phenanthrene and Alkyl Phenanthrene with Humic Acid with Laser Induced Nanoseconds Time Resolved Fluorescence Quenching Method
LIU Yang-zhi, YANG Cheng-hu, ZHU Ya-xian, and ZHANG Yong
Investigations both on the binding properties and mechanisms of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs with humic acid (HA) are crucial to understand the environment behavior and bioavailability of PAHs in aquatic ecosystems. Thus, a novel approach for in situ investigation of the interactions beInvestigations both on the binding properties and mechanisms of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl PAHs with humic acid (HA) are crucial to understand the environment behavior and bioavailability of PAHs in aquatic ecosystems. Thus, a novel approach for in situ investigation of the interactions between parent PAHs and alkyl PAHs, exemplified by Phenanthrene (Phe), 9-Ethylphenanthrene (9-EP) and Retene (Ret), and HA was established by using fluorescence quenching method with laser-induced nanosecond time-resolved fluorescence (LITRF). By changing the delay time of 50 ns, the fluorescent interference of HA can be eliminated effectively and the concentrations of free Phe, 9-EP and Ret can be determined directly. The binding characteristics of the dissolved HA and Phe, 9-EP and Ret were described by Freundlich nonlinear isothermal model. The results of the model parameters and the single point binding coefficients KOC of Phe, 9-EP and Ret with HA by LITRF quenching method were consistent with those of the conventional fluorescence quenching method. Nonlinear bindings of Phe, 9-EP and Ret to HA were also observed because of the parameter n values below 1, and the degree of nonlinearity of Phe was lower than 9-EP and Ret duo to the n value of Phe larger than 9-EP and Ret. At a same given equilibrium concentration, the KOC of Phe was lower than 9-EP and Ret, and that of 9-EP was near to Ret. The binding affinity of the three PAHs increased with decreasing the equilibrium concentration. The binding characteristics of PAHs with HA largely depends on their hydrophobicity, substituent groups and its ability to fit into hydrophobic cavities in HA. The fluorescence lifetimes of Phe, 9-EP and Ret in presence of HA were 36.90, 35.34 and 35.13 ns, meanwhile the fluorescence lifetimes of Phe, 9-EP and Ret in absence of HA were 36.36, 35.34 and 35.84 ns. There was no significant difference of three PAHs fluorescence lifetime with or without HA, indicating the quenching mechanism for Phe, 9-EP and Ret with HA were primarily static quenching. The LITRF quenching method could be used to in situ explore the interactions between PAHs and HA, which could be contribute to realize the PAHs risk assessment in real time..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3332 (2016)
Quantitative Analysis of Mg, Fe and Ca in Jade with Laser Induced Breakdown Spectroscopy
MA Fang-li, DONG Qian-min, LIANG Pei, and WU Yan-xiong
Based on laser induced breakdown spectroscopy and X-ray fluorescence spectroscopy, The calibration curve of the main elements Mg, Cr and trace element Fe in the Jade samples is obtained based on experimental results. In the experiment, LIBS experiment conditions were 3 μs delay, 110 accumulated laser pulse, 100 mJ·Based on laser induced breakdown spectroscopy and X-ray fluorescence spectroscopy, The calibration curve of the main elements Mg, Cr and trace element Fe in the Jade samples is obtained based on experimental results. In the experiment, LIBS experiment conditions were 3 μs delay, 110 accumulated laser pulse, 100 mJ·pulse-1, 10 Hz pulse repetition frequency, plasma in Nanyang jade was induced using nono-second Nd∶YAG (wavelength: 1 064 nm) laser as the excitation source in the atmosphere envtronment of the laboratory. The spectral lines in the 300~1 000 nm wavelength range have been identified with the laser-induced breakdown spectroscopy. Through comparing the characteristic spectrum with the National Institute of standards and Technology Research Institute (NIST) database, the element of Mg, Ca and Fe are found in the Jade samples. Using the X-ray fluorescence spectra analyzed the metal elements Mg, Cr and Fe in Nanyang standard jade and obtained the content of elemental oxides, taking the content as standard data and selecting the high content element Al as internal standard element. According to LIBS calibration curve, we can calculate the content of 3 elements in the measured sample. The result shows that the concentration of elements locate in their corresponding standards range, for example, go(0.28%~1.73%), and Fe2O3 (0~0.8%), CaO ( 18%~20%).Because of its unique features, like the absence of sample preparation, the ability to perform real-time, and in situ analysis as well as the quasi non-destruction and micro-analysis character of the measurements, so as to verify the feasibility of LIBS application in jade..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3337 (2016)
Detection of Chromium Content in Soybean Oil by Laser Induced Breakdown Spectroscopy and UVE Method
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In order to monitor chromium (Cr) content in soybean oil, laser induced breakdown spectroscopy (LIBS) was used to detect Cr content in this research. Pine wood chips was used to enrich heavy metal of Cr, and the spectra of pine wood chips were acquired in the wavelength range of 206.28~481.77 nm by a two-channel high-pIn order to monitor chromium (Cr) content in soybean oil, laser induced breakdown spectroscopy (LIBS) was used to detect Cr content in this research. Pine wood chips was used to enrich heavy metal of Cr, and the spectra of pine wood chips were acquired in the wavelength range of 206.28~481.77 nm by a two-channel high-precision spectrometer. Then, uninformative variable elimination (UVE) method was used to select sensitive wavelength variables for heavy metal of Cr, and calibration model of Cr in soybean oil was developed with partial least squares (PLS) regression, the performance of the calibration model was compared to univariate and full PLS calibration models. The results indicate that the performance of UVE-PLS calibration model is better than that of univariate and full PLS calibration models, the correlation coefficient, root mean square error of calibration (RMSEC), root mean square error of cross validation (RMSECV), root mean square error of prediction (RMSEP) are 0.990, 0.045 mg·g-1, 0.050 mg·g-1 and 0.054 mg·g-1, respectively. After UVE variable selection, the number of wavelength variables in UVE-PLS calibration model is about 2% of wavelength variables in full PLS calibration model. This means UVE is an effective variable selection method which can select correlative variables for heavy metal of Cr..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3341 (2016)
Study Physicochemical Characteristics of Spring Honeys from Yunnan with the Application of HPLC-RI and FAAS
ZHANG Zheng, CHEN Chao, CAO Hong-gang, CAI Sheng-bao, and ZHAO Feng-yun
Many special honeys are produced in Yunnan province due to abundant nectar plants and minerals resources provided by the unique natural environment in this area. In this work, the physicochemical property of three honeys (Viciacracca honey, Hevea brasiliensis honey and Punica granatum honey) from Yunnan was studied. ThMany special honeys are produced in Yunnan province due to abundant nectar plants and minerals resources provided by the unique natural environment in this area. In this work, the physicochemical property of three honeys (Viciacracca honey, Hevea brasiliensis honey and Punica granatum honey) from Yunnan was studied. The results showed that in different honeys the moisture content, electrical conductivity and dynamic viscosity were different. The sugar contents of each honey were determined with HPLC-RI. The results showed that P. granatum honey had the most abundant glucose ［35.62 g·(100 g)-1］, and H. brasiliensis honey had the most abundant fructose ［41.03 g·(100 g)-1］. Thirteen different mineral elements in three honey species were determined with FAAS. It was found that the mineral level was from 167.24 mg·kg-1 in P. granatum honey to 437.34 mg·kg-1 in H. brasiliensis. Based on the mineral content the three honey species were classified following the principal component analysis (PCA) method. The result showed that Cu, Zn and Na could act as the elemental markers for V. cracca honey, while Mg, K, Ca, As and Cd act as the elemental markers for H. brasiliensis honey, and Fe, Mn, Ni, and Cr act as the elemental markers for P. granatum honey. This study reported the physicochemical property of three special Yunnan honeys, which could help the further study and utilization of these honeys..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3346 (2016)
Determination of Cadmium in Shrimp and Shell Fish Samples by Coprecipitation Enrichment with Mn(Ⅱ)-5-Br-PADAP Flame Atomic Absorption Spectrometry
CHEN Qing-hui, WAN Yao-yu, LI Qian, and YAO Jun-xue
A separation/preconcentration procedure with coprecipitation has been proposed for the flame atomic absorption spectrometric (FAAS) determination of cadmium at trace level in food and environmental samples. Manganese(Ⅱ) was used as a carrier which chelated with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol to detect thA separation/preconcentration procedure with coprecipitation has been proposed for the flame atomic absorption spectrometric (FAAS) determination of cadmium at trace level in food and environmental samples. Manganese(Ⅱ) was used as a carrier which chelated with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol to detect the content of trace cadmium in shrimp and shell fish samples with flame atomic absorption spectrometry for the first time. The precipitate could be easily dissolved with concentrated nitric acid. The optimum coprecipitation of this new method including the amount of reagent, amount of manganese(Ⅱ), the pH, and the standing time of the precipitate had been confirmed for the quantitative recoveries of the analytes. The effect of matrix ions and the interference of co-existing ions were also evaluated. Under the experimental conditions established by the optimization step, the system of Mn(Ⅱ)-5-Br-PADAP was able to overcome the matrix interference which showed the effect of separation and enrichment well. The linear range of cadmium content was determined to be 0.1～1.0 mg·L-1. The sensitivity and the relative standard deviation(RSD) were found 0.147(mg·L-1)-1, 0.73%, respectively. The optimum procedure allows the determination of cadmium with limit of detection of 4.27 μg·L-1. The complexity of preprocessing was determined by the complexity of food samples. So the differences of cadmium content in the samples between the direct determination with atomic absorption spectrometry and the measurement after coprecipitation were examined, which providedevidences for the superiority of the system again. Cadmium in shell fish and shrimp samples were 1.85 mg·kg-1 and 1.74 mg·kg-1, which in line with international standards of the Codex Alimentarius Commission(CAC). The credibility of the method was evaluated by standard additional method and recovery experiments. The standard addition recoveries of sample and RSDs of the method were in the range of 99.9%～100.3% and 0.15%～0.83%. The results of recovery experiment showed that the presented coprecipitation procedure had good repetition, high accuracy. In addition, with the method, we could draw conclusions that the experiments were simple and rapid. The developed method described in the literature was successfully applied for the determination of trace cadmium in shrimp and shell fish samples with satisfactory results..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3351 (2016)
Analysis of XRD Spectral Structure and Carbonization of the Biochar Preparation
ZHENG Qing-fu, WANG Zhi-min, CHEN Bao-guo, LIU Gui-feng, and ZHAO Ji
XRD spectroscopy is an important means of research material inside the crystalline structure of the material. In this study it was analyzed with X-ray sources in terms of manner of preparation of different materials carbon crystal structure of biological characteristics and charring mechanism. The results showed that: XRD spectroscopy is an important means of research material inside the crystalline structure of the material. In this study it was analyzed with X-ray sources in terms of manner of preparation of different materials carbon crystal structure of biological characteristics and charring mechanism. The results showed that: Biochar contain d101 and d002 crystal face diffraction peak of carbon graphite-like microcrystalline cellulose, but after charring precipitated salt with different materials, and have a big difference, such as ox dung, castor dregs and furfural dregs of CaCO3 carbon content than other organisms, but only ox dung and castor dregs containing CaMg (CO3)2. Corn stover charcoal preferentially decompose hemicelluloses and cellulose microcrystalline graphite with increasing temperature so with the degree of crystallinity which becomes more stable conversion of carbon compounds. Wherein the mineral salt as a pyrolysis carbonization temperature, gradually precipitated by metals oxides→Acetales→carbonate, and with increasing temperature the content of CaCO3 also increase. After different methods of carbonization, charring its mechanism is different from the first dry charring can promote the decomposition of hemicellulose, high temperature microwave treatment is highly volatile, mainly promoting substances multiple bond rupture decomposed substance carbonate precipitates relatively small. Comprehensive illustrated by X-ray diffraction study biochar may well feature the internal structure of the crystalline, can effectively reflect the cracking mechanism of carbonization process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3355 (2016)
Discovering WDMS with Automatic Classification System Based on RBF Neural Network
WANG Wen-yu, GUO Ge-lin, JIANG Bin, and WANG Li
A model which is capable of capturing the spectral distribution features helps to improve the WDMS(White Dwarf + M Sequence Binaries) classification system running in SDSS-DR10 because the distribution feature of a spectra is one of the most important factors that determine its spectral type. Radial basis function (RBFA model which is capable of capturing the spectral distribution features helps to improve the WDMS(White Dwarf + M Sequence Binaries) classification system running in SDSS-DR10 because the distribution feature of a spectra is one of the most important factors that determine its spectral type. Radial basis function (RBF) neural network is an efficient computational model that is widely used for numerical approximation and object classification. However, due to the reason that the network’s hyper-parameters are usually determined empirically, the performance of the network is limited. In this paper, on the basis of analyzing the distribution features of WDMS in a high dimensional space, an automatic classification model for WDMS ia propose based on RBF neural network. And according to the features, we propose centroids criterion and width criterion to determine hyper-parameters for the network in a more theoretical way, which improves the accuracy of the model. After training and applying the model, a total number of 4 631 WDMS candidates are classified and 25 of them are newly identified, which proves the feasibility of the model and provides further researches on WDMS with more data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3360 (2016)
Outlier Data Mining and Analysis of LAMOST Stellar Spectra in Line Index Feature Space
WANG Guang-pei, PAN Jing-chang, YI Zhen-ping, WEI Peng, and JIANG Bin
Large scale spectrum survey will produce mass spectral data and offer chances for searching rare and unknown types of spectra, which is contribute to revealing the evolution law of the universe and the origin of life. Data mining in outlier data in sky survey can serve the purpose of finding special spectra. Line indexLarge scale spectrum survey will produce mass spectral data and offer chances for searching rare and unknown types of spectra, which is contribute to revealing the evolution law of the universe and the origin of life. Data mining in outlier data in sky survey can serve the purpose of finding special spectra. Line index can be used in spectra data dimension reduction, keeping the spectral physical characteristics as much as possible, and at the same time, it can effectively solve the high dimensional spectral data clustering analysis in the high computation complexity. This paper proposed a method outlier data mining and analysis for massive stellar spectrum survey data based on line index characteristics, according to this, an outlier spectral data analysis method was proposed using line index characteristics space. Experimental results demonstrated that (1) using line index as the characteristic value of the spectrum can quickly perform the outlier data mining for high dimensional spectral data, and it can solve the problem of high computation complexity of the high dimensional spectral data. (2) this outlier data mining method was conducted based on the clustering results; it can effectively finding out emission stars, late type stars, late M type stars, extremely poor metal stars, and even finding spectra data missing certain data. (3) outlier data mining in line index feature space can help to analysis of rules of special stars found in the feature space. The mothed proposed in this paper based on the characteristics of line index outlier data mining and analysis method can be applied to the study of survey data..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3364 (2016)
A Singular Value Decomposition Method for Tunable Diode Laser Absorption Spectroscopy System to Remove Systematic Noises
WANG Zhe, WANG Yan, ZHANG Rui, ZHAO Xue-hong, LIU Qiao-jun, and LI Cong-rong
Detection of gas concentration with tunable diode laser absorption spectroscopy (TDLAS) techniques is affected by baseline drift and high-frequency noise. Therefore, how to remove the systematic noises has been a hot spot. This paper analyzes the significance of singular value decomposition (SVD) in TDLAS detection sysDetection of gas concentration with tunable diode laser absorption spectroscopy (TDLAS) techniques is affected by baseline drift and high-frequency noise. Therefore, how to remove the systematic noises has been a hot spot. This paper analyzes the significance of singular value decomposition (SVD) in TDLAS detection system with two different methods of constructing a matrix, and it discusses the differences of processing results for different noises. The second harmonic signal is arranged in a matrix and decomposed. We select the appropriate threshold and putthose singular values smaller than the threshold into zero, then reconstruct the matrix. Experiments show that SVD method does not require additional system components or pass into the zero gas to subtract background. This method is able to remove noises of TDLAS system quickly and effectively. We found that the method of constructing a hankel matrix is suitable for removing high-frequency noise. However, the method of constructing a continuous-cutoff-signal matrix is suitable for removing baseline drift. For example, we set up a TDLAS system to measure the concentration of NH3 while the noise removal rate of the second harmonic curve is up to 80% with this method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3369 (2016)
Granary Temperature Measurement Network Based on Chirped FBG
LIU Zhi-chao, YANG Jin-hua, ZHANG Liu, and WANG Gao
In conventional optical fiber grating temperature measuring system, it can be loaded into a small number of fibers grating probe. At the same time, the intensity of back waves is relatively weak, and its multiplexing capability is poor. In order to solve these problems, temperature measurement system was designed basedIn conventional optical fiber grating temperature measuring system, it can be loaded into a small number of fibers grating probe. At the same time, the intensity of back waves is relatively weak, and its multiplexing capability is poor. In order to solve these problems, temperature measurement system was designed based on chirped Fiber Bragg Grating. Its purpose is to obtain large-scale, multi-point temperature measurement data. The bandwidth of back waves was improved by chirp modulation techniques, so that available processing power of signal was increased, and the number of the chirped FBG probe in one fiber was greatly increased. Grating period expression was derived in chirp modulation, and modulation method and the wavelength range was provided. In the experiment, LPT-102 broadband light source and the FP optical fiber demodulator were used, and the modulation bandwidth of the system was from 1 535.0 to 1 555.0 nm. It used the WR-201 type temperature sensor as calibrated detector. Experimental results show that when the temperature changed by 1 ℃ from 20~60 ℃, the test temperature error would be closed with traditional Fiber Bragg Grating probe and chirped Fiber Bragg Grating probe, and they both meet the design requirements. In contrast, the wavelength shift data of chirped FBG was more monotone linear than the characteristic FBG, so its data was more stable. Meanwhile, in one fiber, the number of probes in the chirped FBG system was greatly more than the Uniform FBG system. In the original FBG system, without increasing the number of optical fiber or reduced the temperature measurement accuracy, design requirements for increase with the number of probe points in the system was achieved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3377 (2016)
Effects of the DLA Light Source Quality on the Beam Quality of Combined Beam in Spectral Beam Combining Systems with Grating-External Cavity
YANG Lei, ZHONG Zhe-qiang, WU Zhen, and ZHANG Bin
In Diode Laser Array (DLA) spectral beam combining (SBC) systems with grating-external cavity, the beam quality of the combined beam tends to degrade due to comprehensive function of factors involving divergence angle of light, positional deviation and direction angle deviation caused by “smile” effect of emitters, etcIn Diode Laser Array (DLA) spectral beam combining (SBC) systems with grating-external cavity, the beam quality of the combined beam tends to degrade due to comprehensive function of factors involving divergence angle of light, positional deviation and direction angle deviation caused by “smile” effect of emitters, etc.. Based on the consideration of the effects of the divergence angle and “smile” effect of DLA emitters on the beam propagation characteristics, the light propagation model of DLA SBC systems with grating-external cavity has been built up, and the effects of divergence angle and the positional deviation and direction angle deviation caused by “smile” effect of DLA emitters on the beam quality of the combined beam in SBC systems have been analyzed quantitatively. The results indicate that, the beam quality of the combined beam would be significantly affected by the DLA light source quality, i.e., the bigger the divergence angle and the direction angle deviation caused by “smile” effect are, the worse the beam quality of the combined beam is. The positional deviation of emitters in beam-combination direction caused by “smile” effect has little impact on the beam quality of the combined beam, whereas the positional deviation in non beam-combination direction would significantly degrade the beam quality of the combined beam. In practical applications, measures should be taken to improve the DLA light source quality in order to eliminate the effect on the beam quality of the combined beam..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3381 (2016)
Analysis of Glass Surface Modification with Ion Beam Based on Ellipsometry
SUN Yao, and WANG Hong
Etching treatment was performed on glass surface by dissociated nitrogen using anode layer linear ion source. The changes of glass surface after surface modification was analyzed and the effect of ionization voltage on surface roughness, refractive index and optical thickness was investigated. Accordingly, the relationEtching treatment was performed on glass surface by dissociated nitrogen using anode layer linear ion source. The changes of glass surface after surface modification was analyzed and the effect of ionization voltage on surface roughness, refractive index and optical thickness was investigated. Accordingly, the relationship between Δ spectral characteristics of fixed wavelength changed angle of incidence and refractive index, Brewster angle, surface roughness and optical thickness was discussed through the comparison of Δ spectrum under different surface conditions based on spectroscopic ellipsometry. The results show that the shape of Δ spectrum near Brewster angle changes, the abrupt change of Δ spectrum shifts to larger angle, and the slope of Δ spectrum increase at the same time. Modeling and fitting analysis reveals that an optically denser layer was produced, the refraction index and Brewster angle increase and surface roughness decrease of glass caused by nitrogen ion beam etching treatment. However, the refraction remains consistence, and the depth of denser layer increase with increasing ionization voltage. The surface morphology analysis by AFM verified the leveling effect of glass surface by nitrogen ion beam. XPS measurement indicates the optional sputtering of glass surface by nitrogen ion beam, inferring the generation of denser layer arises from the compaction of ion beam. Furthermore, the general relationship between the characteristic of Δ spectrum and surface conditions of materials was theoretical derived and verified, and an evaluation of material surface variations was proposed. Such as the increase of abrupt change angle illustrates the increase of refractive index and Brewster angle, the increase of slope demonstrates the decrease of surface roughness, the increase of sharp corner of both sides evident the increase of optical thickness, vice-versa..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3388 (2016)
Growth and Characteristics of ZnO Needles in the Surface of “Platanus Occidentalis” Made of Al2O3, Au and ZnO
Zhu Lin, Cui Haining, B. Marí, Wang Yixin, Wang Rong, and Li Xiaoxia
Complex ZnO compound material has great potential applications for optoelectronic devices. In this article, we give report to a simulation growth of a kind of special“fruiting ball”——natural “Platanus Occidentalis” made of Al2O3, Au and ZnO. The surface of “Platanus Occidentalis ” has numerous tiny Au seeds on the surfComplex ZnO compound material has great potential applications for optoelectronic devices. In this article, we give report to a simulation growth of a kind of special“fruiting ball”——natural “Platanus Occidentalis” made of Al2O3, Au and ZnO. The surface of “Platanus Occidentalis ” has numerous tiny Au seeds on the surface of Al2O3 ball. ZnO needles synthesized by the electrodeposition technique grow well on the Au seed layer. The obtained mono dispersive needles (or hexagonal columns) have different distribution density. The prepared sample looks like the assembled “Platanus Occidentalis” in photographs of scanning electron microscopy (SEM). Photoluminescence (PL) of samples at 6 K temperature and other characteristics are investigated. The appearance of sharp bound exciton (BE) emission line and the longitudinal optical (LO)-phonon replicas imply that the ZnO nanocolumns are of high optical quality..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3394 (2016)
Near Infrared Spectroscopy Study on Nitrogen in Shortcut Nitrification and Denitrification Using Principal Component Analysis Combined with BP Neural Networks
HUANG Jian, HUANG Shan, ZHANG Hua, HUANG Xian-huai, ZHANG Yong, TAO Yong, TANG Yu-chao, and WANG Meng
To achieve efficient nitrogen removal and rapid detection of ammonia nitrogen and nitrite nitrogen, principal component analysis and neural networks were used to establish quantitative analysis model of ammonia nitrogen and nitrite nitrogen in shortcut nitrification and denitrification based on near infrared spectroscoTo achieve efficient nitrogen removal and rapid detection of ammonia nitrogen and nitrite nitrogen, principal component analysis and neural networks were used to establish quantitative analysis model of ammonia nitrogen and nitrite nitrogen in shortcut nitrification and denitrification based on near infrared spectroscopy—BP neural networks model. The results showed that ammonia nitrogen concentration decreased from 45.3 to 2.7 mg·L-1 after aerobic, and nitrite nitrogen concentration increased from 0.01 to 19.6 mg·L-1, while nitrite nitrogen concentration decreased from 19.6 to 1.2 mg·L-1 after anoxic, which means that rapid nitrification and denitrification are successfully achieved. The principal component analysis of the original near infrared spectra for water samples showed the first 13 principal components represented the information of the original spectrum data, with cumulative contribution rate being 95.04%. In this way, redundant information can be eliminated to reduce the number of dimensions in the model. The spectral data matrix is accordingly reduced from 192×2203 to 192×13, which contributes greatly to easier calculations and improves the accuracy of the model. The correction results of BP neural networks model showed the coefficient of determination for ammonia nitrogen and nitrite nitrogen concentration was 0.950 4 and 0.976 2 respectively, with the root mean square error of calibration being 0.016 6 and 0.010 9. BP neural networks model yields predicted values fitting well with the expected values for ammonia nitrogen and nitrite nitrogen concentration, with R2 being 0.974 0 and 0.981 4 respectively, with the root mean square error of prediction being 0.033 7 and 0.028 7, suggesting that BP neural networks model had a good prediction results for ammonia nitrogen and nitrite nitrogen concentration. The study demonstrated that ammonia nitrogen and nitrite nitrogen concentration can be rapidly predicted with BP neural networks based analysis of the near infrared spectroscopy of the water sample in shortcut nitrification and denitrification, which may provide timely and flexible control to shortcut nitrification and denitrification operation according to the ammonia nitrogen and nitrite nitrogen concentration changes, and makes a quick and effective detection technique for denitrification..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3399 (2016)
Raman Spectra of Bredigite at High Temperature and High Pressure
XIONG Zhi-hua, ZHAO Ming-zhen, HE Jun-guo, LI Yi-peng, and LI Hong-zhong
Bredigite was synthesized by using the Piston-Cylinder in 1.2 GPa and 1 473 K. With external heating device and diamond anvil cell, high temperature and high pressure Raman spectra of bredigite were collected at temperatures 298, 353, 463, 543, 663, 773 and 873 K and with pressure from 1 atm up to 14.36 GPa (room tempeBredigite was synthesized by using the Piston-Cylinder in 1.2 GPa and 1 473 K. With external heating device and diamond anvil cell, high temperature and high pressure Raman spectra of bredigite were collected at temperatures 298, 353, 463, 543, 663, 773 and 873 K and with pressure from 1 atm up to 14.36 GPa (room temperature). The SEM image showed that the sample consisted of one crystalline phase with grain size ranging from 10～20 μm. The EPMA data suggest a chemical formula of Ca7.03(2)Mg0.98(2)Si3.94(2)O16 which was identical to the theoretical component of bredigite. The Raman spectroscopic results indicate there were 29 vibration bands of bredigite at high temperature. Some bands were merging, weakening and disappearing increasingly with the temperature, which was obvious in the range of 800~1 200 cm-1. The vibration bands of 909, 927 and 950 cm-1 disappeared at 873, 773 and 873 K, respectively. The results primarily indicated that the structure of bredigite was stable under experimental condition. In addition, isobaric mode-Grüneisen parameters and isothermal mode-Grüneisen parameters were calculated, yielding 1.47(2) and 0.45(3) as their mean values, respectively. Anharmonic coefficients were estimated based on the high temperature and high pressure Raman experiments, showing that the contributions to anharmonic-effect induced with the Si—O vibration modes were smaller than other modes..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3404 (2016)
The Effect of Chlorophyll Concentration of Paddy Rice on the Fluorescence Spectrum
YANG Jian, GONG Wei, SHI Shuo, DU Lin, SUN Jia, SONG Sha-lei, and MA Ying-ying
In order to enhance the monitoring of paddy growth, utilize the fertilizer more efficiently, increase crop yield and improve the quality of grain, thus the system of laser-induced fluorescence (LIF) was built. The system was designed to study the relationship between the rice leaf chlorophyll content and fluorescence rIn order to enhance the monitoring of paddy growth, utilize the fertilizer more efficiently, increase crop yield and improve the quality of grain, thus the system of laser-induced fluorescence (LIF) was built. The system was designed to study the relationship between the rice leaf chlorophyll content and fluorescence ratio. In this paper, the samples came from the second upper leaves of paddy in shooting stage and the cultivated area was located in Jianghan plain of China. Firstly, the Kjeldahl method combined with the formula which was described by Zivcak et al. was utilized to calculate the chlorophyll content of paddy, then the fluorescence spectrum of paddy leaf with different chlorophyll content by the instrument of laser-induced fluorescence (the wavelength of excitation 355 nm). Fluorescence spectra of paddy leaf with different chlorophyll content were collected and then a fluorescence spectra database was established. It is discussed that the relationship between the ratio of fluorescence (F740/F685 is the ratio of fluorescence intensity of 740 nm dividing that by 685 nm) and the chlorophyll content of paddy. It is found that the effect of chlorophyll content on the fluorescence spectral characteristics is evident. The results demonstrated that it has the tightly positive correlation between the fluorescence ratio (F740/F685) and chlorophyll content of paddy leaf. The determination coefficient (R2) can reach up to 0.901 3 and 0.912 5 at tillering stage and shooting stage, respectively. The experimental analysis showed that the LIF technology has the advantages of convenient, quick and nondestructive, and it has the potential for quantitative monitoring of crop growth..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3410 (2016)
Probing the Binding of Torasemide to Pepsin and Trypsin by Spectroscopic and Molecular Docking Methods
WANG Yi-run, FANG Qing, GUO Chen-hui, and LIU Ying
Torasemide (TOR) belongs to the pyridine sulfonylurea class of loop diuretics and is widely and effectively used in the treatment of hypertension, heart failure, chronic renal failure and liver disease. One of the adverse reactions caused by TOR was a slight gastrointestinal discomfort in the course of treatment. HowevTorasemide (TOR) belongs to the pyridine sulfonylurea class of loop diuretics and is widely and effectively used in the treatment of hypertension, heart failure, chronic renal failure and liver disease. One of the adverse reactions caused by TOR was a slight gastrointestinal discomfort in the course of treatment. However, the molecular interactions of TOR with digestive proteases (trypsin and pepsin) rarely reported. The attempt of this paper was to completely investigate the binding characteristics between TOR and trypsin or pepsin at different temperatures under imitated physiological conditions by fluorescence spectroscopy, UV-vis absorption, circular dichroism (CD) and molecular modeling technique. The inner filter effect of all fluorescence data in the paper was eliminated to get accurate binding parameters. It was found that the fluorescence quenching of trypsin and pepsin by TOR was a static quenching type. The Stern-Volmer quenching constants (KSV) of TOR-pepisn and TOR-trypsin were inversely correlated with temperatures. The binding of TOR changed the conformational structures and internal micro-environment of pepsin and trypsin by UV-vis absorption, synchronous fluorescence, three dimensional (3D) fluorescence and circular dichroism (CD) spectroscopy. The results showed the polarity around Tyr residues of pepsin or trypsin was changed more obviously than that around Trp residues, the TOR alters the secondary structure of trypsin and pepsin and reduces the β-sheet content of protein, which may affect its physiological function. The molecular docking results showed that TOR inserted into the active site of pepsin to interact with the catalytic residues Asp32 and Asp215, and caused a decrease in pepsin activity. TOR bound into the primary substrate-binding pocket (S1 binding pocket) of trypsin by hydrophobic forces and affected the function of trypsin by increasing its catalytic activity. Our results offer insights for the binding and toxicity mechanism of TOR with pepsin and trypsin in vivo, which provides important information for using the TOR safely..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3414 (2016)
Distribution of Mineral Elements and Influencing Factors in Scalp Hair of Childbearing Age Women in the County of Xinghe, Inner Mongolia of China
ZHOU Shan-shan, and LIU Ying
The distribution and influencing factors on age, reproductive history and dietary habits in scalp hair of rural childbearing female in the county of XingHe, Inner Mongolia of China were studied. 21 mineral elements including essential and toxic elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Se, Si, SnThe distribution and influencing factors on age, reproductive history and dietary habits in scalp hair of rural childbearing female in the county of XingHe, Inner Mongolia of China were studied. 21 mineral elements including essential and toxic elements (Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Se, Si, Sn, Sr, Ti, V and Zn ) in scalp hair samples from 180 females of childbearing age were measured with inductively coupled plasma-atomic emission spectrometry (ICP-AES) and atomic fluorescence spectrometry (AFS), respectively. The results demonstrated that the content of the most mineral elements (B, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Se, Si, Sn, Sr, Ti, V and Zn) existed in a descending order in the hair of young age group (18～29 years) to the elder age group (40～45 years), while elements of Ca, Mg, Mn and Pb were found to have the lowest content in the middle age group (30～39 years). Women having two children were more likely to have the lowest content of Ca, Mg, Mn, Mo, Ni, Pb, Sn, Sr and Zn due to the increased numbers of pregnancies, the statistically correlations had been proved among Ca, Pb and Sn. In addition, dietary habits also can affect the level of the mineral elements in hair, for example, consuming suancai food frequently can cause lower level of Zn, Fe, Cu, Mn, Sr, Mo and Pb, but higher Se, the frequent intake of meat resulted in increased content of Zn and Se. The individuals that declared intaking vegetables regularly had more Si in their hair. Also, daily intake of fruit leads to higher level of Mn, Ni and Ti. This study will provide basic and useful information when addressing reproductive and women health challenges in the rural areas where poor dietary habits are prevailing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3422 (2016)
Study on Heavy Metal Detection in Soil with Improved EDXRF
YU Jie, HONG Xu, MA Ying-jie, ZHOU Jian-bin, WANG Yi-qiang, WANG Min, and LU Yuan-sheng
Due to the low precision and accuracy of trace heavy metals detection wiith traditional energy dispersive X-ray fluorescence (EDXRF) system, an improved EDXRF system is proposed. In order to reduce the influence of reflected rays, the sample is irradiated with the incident X-rays vertically, and the detector is placed Due to the low precision and accuracy of trace heavy metals detection wiith traditional energy dispersive X-ray fluorescence (EDXRF) system, an improved EDXRF system is proposed. In order to reduce the influence of reflected rays, the sample is irradiated with the incident X-rays vertically, and the detector is placed in parallel with the sample’s section. The sample is connected with detector through collimator. With improved EDXRF measures certified reference materials, the results show that the detection limit of the improved EDXRF system for Mo, Zn, Cu, Pb, Zr, Nb is 0.4, 6.68, 1.97, 6.84, 1.60, 7.59 mg·kg-1 respectively and the logarithm deviation of each element in the standard samples is between 0 and 0.05. The RSD%(GBW) is less than 7 as the element content is more than three times of the detection limit, and it is below 15 when the element content is less than three times of the detection limit. The soil samples collected from Da Xing’an Ling region are applied to verify the improved EDXRF system. The proposed EDXRF system can improve the measurement accuracy of trace heavy metal detection in soil, satisfying the requirements of geologic exploration..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3429 (2016)
Study on Internal Information of the Two-Layered Tissue by Optimizing the Detection Position
LIU Yan, YANG Xue, ZHAO Jing, LI Gang, and LIN Ling
As to most methods of detecting the inner information of inhomogenous tissue, a significant issue is that the detection position is ambiguous because of the complexity of human tissue structure and discrepancies among individuals. This paper studies the best source-detector distance (SDSbest) to detect internal informaAs to most methods of detecting the inner information of inhomogenous tissue, a significant issue is that the detection position is ambiguous because of the complexity of human tissue structure and discrepancies among individuals. This paper studies the best source-detector distance (SDSbest) to detect internal information of a fat-muscle tissue with spatially resolved diffuse reflectance spectra. In order to weaken the measurement error caused by the discrepancies among individuals and multiple backscattered photons, and according to the transmission model of light in complex biological tissue, then we added the constraint condition——two ideal “banana shape” paths——to define the effective photon ratio(SNR), which was used to select the best source-detector separations (SDSbest), and the results from Monte Carlo simulation modified by adding constraint condition were statistically analyzed, and we regard the SNR as a basis and analyze the relationship between the fat thickness (hf), the absorption coefficient of a fat layer (μaf), the absorption coefficient of a muscle layer (μam) and the source-detector distance (SDS), and hf is used as the independent variable to develop a linear regression model to predict SDSbest. The result showed that μaf and μam have no effect on SDSbest when 0
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3434 (2016)
Analytic Study on the Characteristics of Infrared Spectrum of Oil Pool Flame
LIU Hong-tao, CHEN Zhi-li, HU Tan-gao, LIANG Jian-jun, LIU Qiang, and WEI Xiao-lin
In virtue of the severity and scale of the pollution caused by oil pool flame, space remote sensing can provide us a new way of monitoring in real time the oil pool flame pollution. Space remote sensing monitoring is based on the analysis of target spectrum characteristics. Due to lack of adequate researches on the chaIn virtue of the severity and scale of the pollution caused by oil pool flame, space remote sensing can provide us a new way of monitoring in real time the oil pool flame pollution. Space remote sensing monitoring is based on the analysis of target spectrum characteristics. Due to lack of adequate researches on the characteristics of infrared spectrum of oil pool flame, this paper carries out the analytical study on flame spectrums of several types of oil, mixed oil and other combustible objects in outdoor space by establishing all-flame infrared testing system with the spectrum range of 1～14 μm. The results show that the spectrum curves of oil pool flame of 92# gasoline, 95# gasoline, 0# diesel, aviation kerosene and lube have similar features, that there exist characteristics emission peaks at the area of certain wave lengths—H2O characteristics emission peak for 1.1, 2.4, 2.8 and 6.3 μm, CO2 characteristics emission peak for 4.2 and 4.5 μm, C—H stretching vibration emission peak for 3.4 μm, and no obvious characteristics peak for spectrum curves of 6.3 μm and above; that there is no obvious difference in the spectrum of oil pool flame among the mixtures of 92# gasoline and 0# diesel at different proportions, that the comparison of the flame spectrum of 92# gasoline with that of wood and paper shows that there appears a characteristics emission peak at 3.4 μm; that though the flame spectrum of alcohol has similar radiated emission near 3.4 μm, the proportion of its radiation intensity to that of CO2 at 4.5 μm is far less than that for the flame spectrum of 92# gasoline; that the flame spectrum of honeycomb briquette is similar to that of gray body radiation. The differences in flame spectrum among all kinds of combustible materials are closely linked to their chemical compositions and burning reaction mechanisms. Comparative analysis on the spectrum characteristics at continuous area, intermission area and flue gas area shows that C—H stretching vibration peak only exists in continuous area, which proves that the emission peak is caused by the combustible reaction of oil and gas. This result is in line with the mechanism of oil pool combustion reaction. The experimental conclusion is of great significance in the remote-sensing recognition of oil pool flame based on the analysis of spectrum characteristics..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 3442 (2016)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 10, 1 (2016)
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