Journals >Spectroscopy and Spectral Analysis
Contents
2014
Volume: 34 Issue 5
59 Article(s)
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Research Article
Influence of Slide-Blown on Plasma Characterization of Laser Dressing for Bronze-Bonded Diamond Wheel by a Fiber Laser
ZHANG Yong, CHEN Gen-yu, ZHOU Cong, DENG Hui, XU Jian-bo, and ZHOU Xing-cai
The effects of assistant side-blown operating parameters on the behavior of plasma characteristics and plasma geometry were studied with the aid of high-speed camera in laser dressing of bronze-bonded diamond grinding wheel. The results showed that: high pressure argon plasma reduces swelling height, and as the pressurThe effects of assistant side-blown operating parameters on the behavior of plasma characteristics and plasma geometry were studied with the aid of high-speed camera in laser dressing of bronze-bonded diamond grinding wheel. The results showed that: high pressure argon plasma reduces swelling height, and as the pressure increases, argon blowing side of the plasma effect is more obvious. Plasma emission spectrum was studied on the grinding wheel radial maximum value with the change in argon gas pressure through the acquisition of plasma emission spectroscopy using spectrometer, and according to the Boltzmann slash and Stark broadening method, the maximal values of plasma electron temperature and electron density in the wheel radial were calculated. It was found that the plasma spectral line intensity first increased and then decreased as gas pressure reached the peak at 0.2 MPa, Larger argon pressure can significantly reduce the temperature and density of plasmas. With optical 3D scanner the wheel surface topography before and after adding side-blown gas was compared. The results indicated that: the topography of grinding wheel with 0.5 MPa side-blown argon is better than that without adding side-blown gas..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1153 (2014)
Reflectance Characteristics of Rare Earth Solution with Different Concentrations
DAI Jing-jing, WANG Deng-hong, LI Qing-ting, and CHEN Zheng-hui
In the present paper, ten aqueous samples which contain different concentrations of REE were collected in south Jiangxi province, and the reflectance spectra and the concentrations of REE were measured by analytical spectral devices (ASD) FieldSpec-3 reflectance spectroscopy and inductively coupled plasma mass spectromIn the present paper, ten aqueous samples which contain different concentrations of REE were collected in south Jiangxi province, and the reflectance spectra and the concentrations of REE were measured by analytical spectral devices (ASD) FieldSpec-3 reflectance spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The results show that the spectra presented mix characteristics of pure water and rare earth oxide. In addition, six diagnostic absorption features caused by REE in visible and near-infrared wavelengths were detected. Then, relative absorption depths of the six absorption wavelength were calculated by the ratio spectra of sample spectra and pure water spectra. Finally, concentrations of total REE of ten samples and relative absorption depths of the six absorption wavelength were selected as two factors, and their relationship was perfectly described using linear regression analysis in which correlation coefficient was up to 96%-97%. The study provides a new method for quantitative estimation of different concentrations of dissolved REE in aqueous media, and strengthens theoretical basis for hyperspectral information extraction of REE..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1158 (2014)
Applied Research on the Physical Model for Calculating Optical Constant of Metal Oxide Films
LIU Hua-song, JIANG Cheng-hui, WANG Li-shuan, LIU Dan-dan, JIANG Yu-gang, SUN Peng, and JI Yi-qin
In the present paper, two metal oxide films of HfO2 and Ta2O5 were prepared by ion beam sputtering technology. Through measuring ellipsometric parameters of HfO2 and Ta2O5 films, their optical constants can be inversion-calculated by nonlinear least squares techniques. In the fitting process, eight experiment groups weIn the present paper, two metal oxide films of HfO2 and Ta2O5 were prepared by ion beam sputtering technology. Through measuring ellipsometric parameters of HfO2 and Ta2O5 films, their optical constants can be inversion-calculated by nonlinear least squares techniques. In the fitting process, eight experiment groups were arranged by the orthogonal table L8(27). After selecting Cauchy model, the largest influencing factor for fitting optical constant of HfO2 is surface layer model and the largest influencing factor for fitting optical constant of Ta2O5 is refractive index gradient model. The impact of different physical model on MSE and the order for selecting model in the fitting process are determined. According to the selecting model and the determined fitting order, optical constants of the two metal oxide films were inversion-calculated with adding weak absorption model, and the obtained MSE can descend 79% and 39% according to the initial value. The results indicated that the selecting model possesses definite physical significance in the fitting process. The obtained method can be applied in inversion-calculating many metal oxide films with weak absorption. It has wide application value. At 500 nm, the refractive index gradient of Ta2O5 films is greater than HfO2 films, while the extinction coefficient of HfO2 films is greater than Ta2O5. It was shown that Hf metal is easier to form stable oxide than Ta metal. And the absorption of HfO2 films is larger than Ta2O5 films..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1163 (2014)
Impact of Introduction of O2 on the Welding Arc of Gas Pool Coupled Activating TIG
HUANG Yong, WANG Yan-lei, and ZHANG Zhi-guo
In the present paper, Boltzmann plot method was applied to analyze the temperature distributions of the arc plasma when the gas pool coupled activating TIG welding was at different coupling degrees with the outer gas being O2. Based on this study of temperature distributions, the changing regularities of arc voltage anIn the present paper, Boltzmann plot method was applied to analyze the temperature distributions of the arc plasma when the gas pool coupled activating TIG welding was at different coupling degrees with the outer gas being O2. Based on this study of temperature distributions, the changing regularities of arc voltage and arc appearance were studied. The result shows that compared with traditional TIG welding, the introduction of O2 makes the welding arc constricted slightly, the temperature of the arc center build up, and the arc voltage increase. When argon being the inner gas, oxygen serving as the outer gas instead of argon makes the arc constricted more obviously. When the coupling degree increases from 0 to 2, the temperature of the arc center and the arc voltage both increase slightly. In the gas pool coupled activating TIG welding the arc is constricted not obviously, and the reason why the weld penetration is improved dramatically in the welding of stainless steel is not arc constriction..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1168 (2014)
Study of the Effect of Heat Source Separation Distance on Plasma Physical Properties in Laser-Pulsed GMAW Hybrid Welding Based on Spectral Diagnosis Technique
LIAO Wei, HUA Xue-ming, ZHANG Wang, and LI Fang
In the present paper, the authors calculated the plasma’s peak electron temperatures under different heat source separation distance in laser- pulse GMAW hybrid welding based on Boltzmann spectrometry. Plasma’s peak electron densities under the corresponding conditions were also calculated by using the Stark width of tIn the present paper, the authors calculated the plasma’s peak electron temperatures under different heat source separation distance in laser- pulse GMAW hybrid welding based on Boltzmann spectrometry. Plasma’s peak electron densities under the corresponding conditions were also calculated by using the Stark width of the plasma spectrum. Combined with high-speed photography, the effect of heat source separation distance on electron temperature and electron density was studied. The results show that with the increase in heat source separation distance, the electron temperatures and electron densities of laser plasma did not changed significantly. However, the electron temperatures of arc plasma decreased, and the electron densities of arc plasma first increased and then decreased..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1173 (2014)
Performance of Wavelength Modulation Surface Plasmon Resonance Biosensor
LUO Yun-han, XU Meng-yun, CHEN Xiao-long, TANG Jie-yuan, WANG Fang, ZHANG Yi-long, HE Yong-hong, and CHEN Zhe
Surface plasmon resonance (SPR) is a rapid, label-free, high-precision technique of biological sensing and analysis. The investigation on the characteristics of provides theoretical basis and instructions for the applications of SPR. A Kretschmann-structure surface plasmon resonance (SPR) biosensor based on wavelength Surface plasmon resonance (SPR) is a rapid, label-free, high-precision technique of biological sensing and analysis. The investigation on the characteristics of provides theoretical basis and instructions for the applications of SPR. A Kretschmann-structure surface plasmon resonance (SPR) biosensor based on wavelength modulation was developed, and also its sensing performances in the bulk solution was investigated. Measurements with different concentrations of bulk ethanol and ethylene glycol solutions show that the resonant wavelength shows a low sensitivity, but a higher linear response to the change in refractive index (RI), when RI is relatively smaller. With increasing refractive index , the sensitivity of resonance wavelength to changes in the refractive index increases. In the refractive index range of 1.407 0～1.430 RIU, sensitivity reaches to 11 487 nm·RIU-1. The sensor resonance wavelength stability is 0.213 8 nm, and the minimum resolution of refractive index approaches to 10－6 RIU. The advantages of the surface plasmon resonance sensor developed here results in simple operation, high sensitivity, wide detection range, low resolution, makes it an important candidate in chemical and biological sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1178 (2014)
Study on the Emission Spectrum of Microwave Plasma in Liquid
WANG Bo, SUN Bing, ZHU Xiao-mei, YAN Zhi-yu, LIU Yong-jun, and LIU Hui
After the technology of microwave discharge in liquid is realized for the first time in China, the basic physical phenomena and characteristic of microwave discharge in liquid is studied in order to lay a theoretical foundation of research on microwave discharge in liquid. In the present paper, the active particles genAfter the technology of microwave discharge in liquid is realized for the first time in China, the basic physical phenomena and characteristic of microwave discharge in liquid is studied in order to lay a theoretical foundation of research on microwave discharge in liquid. In the present paper, the active particles generated by microwave discharge in liquid were detected using the emission spectrometer, and the statistical method of spectrum data of microwave discharge in liquid was also studied. The emission spectrometer and numerically controlled camera were used to detect synchronously the process of the initial discharge and stable discharge of microwave discharge in liquid. The results show that: the emission intensity of microwave plasma in liquid has a large fluctuation, and the spectrum intensity can be calculated using the average of 10 spectrum data points. The intensity of discharge is reflected by the plasma area in a certain extent, however, the variation gradient of the intensity of discharge is different from that of the plasma area. This is mainly because that, in the process of discharging, the discharge intensity is not only reflected by the plasma area, but also reflected by the brightness of the plasma..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1182 (2014)
Absorption Spectrum of Quasi-Continuous Laser Modulation Demodulation Method
SHAO Xin, LIU Fu-gui, DU Zhen-hui, and WANG Wei
A software phase-locked amplifier demodulation method is proposed in order to demodulate the second harmonic (2f) signal of quasi-continuous laser wavelength modulation spectroscopy (WMS) properly, based on the analysis of its signal characteristics. By judging the effectiveness of the measurement data, filter, phase-sA software phase-locked amplifier demodulation method is proposed in order to demodulate the second harmonic (2f) signal of quasi-continuous laser wavelength modulation spectroscopy (WMS) properly, based on the analysis of its signal characteristics. By judging the effectiveness of the measurement data, filter, phase-sensitive detection, digital filtering and other processing, the method can achieve the sensitive detection of quasi-continuous signal. The method was verified by using carbon dioxide detection experiments. The WMS-2f signal obtained by the software phase-locked amplifier and the high-performance phase-locked amplifier (SR844) were compared simultaneously. The results show that the Allan variance of WMS-2f signal demodulated by the software phase-locked amplifier is one order of magnitude smaller than that demodulated by SR844, corresponding two order of magnitude lower of detection limit. And it is able to solve the unlocked problem caused by the small duty cycle of quasi-continuous modulation signal, with a small signal waveform distortion..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1186 (2014)
94 km Brillouin Distributed Optical Fiber Sensors Based on Ultra-Long Fiber Ring Laser Pumping
YUAN Cheng-xu, WANG Zi-nan, JIA Xin-hong, LI Jin, YAN Xiao-dong, and CUI An-bin
A novel optical amplification configuration based on ultra-long fiber laser with a ring cavity was proposed and applied to Brillouin optical time-domain analysis (BOTDA) sensing system, in order to extend the measurement distance significantly. The parameters used in the experiment were optimized, considering the main A novel optical amplification configuration based on ultra-long fiber laser with a ring cavity was proposed and applied to Brillouin optical time-domain analysis (BOTDA) sensing system, in order to extend the measurement distance significantly. The parameters used in the experiment were optimized, considering the main limitations of the setup, such as depletion, self-phase modulation (SPM) and pump-signal relative intensity noise (RIN) transfer. Through analyzing Brillouin gain spectrum, we demonstrated distributed sensing over 94 km of standard single-mode fiber with 3 meter spatial resolution and strain/temperature accuracy of 28 /1.4 ℃..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1191 (2014)
Preliminary Research on Insect Damage Detection in Pecans Using Terahertz Spectroscopy
LI Bin, WANG Ning, ZHANG Wei-li, ZHAO Chun-jiang, and ZHANG Bao-hua
Pecan is an important nut in US, however, the inner insect influences pecan’s quality a lot. To realize the nondestructive detection of insect damage in American pecans rapidly and efficiently, preliminary research on insect damage detection in pecans was conducted based on terahertz spectroscopy. Firstly, a set of natPecan is an important nut in US, however, the inner insect influences pecan’s quality a lot. To realize the nondestructive detection of insect damage in American pecans rapidly and efficiently, preliminary research on insect damage detection in pecans was conducted based on terahertz spectroscopy. Firstly, a set of native pecan nuts were collected and were manually sliced with a thickness of about 1, 2 and 3 mm and with a size of about 2 cm(length)×1 cm(width) for every pecan nutmeat; Pecan shell and inner separator were also cut into the same size. Secondly, the absorption spectra of the nutmeat slices, shell, and inner separator were collected using THz time-domain spectroscopy (THz-TDS) developed by a group of researchers at Oklahoma State University, and the spectral characteristic of the slices was analyzed. Thirdly, the absorption spectra of the alive manduca sexta and dry pecan weevil were collected, and due to the high contents in the insects, very obvious spectral characteristics were found. Finally, the transmission experiment was conducted with the whole pecans. The results from the preliminary study show a potential application of THz technology for insect damage detection. This research provides a reference for further understanding terahertz and exploring sample preparation methods, test methods, data acquisition and optical parameters calculation methods, and developing nondestructive detection system for insect damage in American pecans based on terahertz technology..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1196 (2014)
Study on the Inclusion Compound of Avermectin by Infrared Spectroscopy
SHEN Wen, ZHANG Guang-hua, GUO Ning, and LI Yun-tao
This study was designed to investigate the formation and effect of inclusion complex of Avermectin-β-cyclodextrin based on the accommodation property of β-cyclodextrins molecular cavity. The inclusion complex of Avermectin-β-cyclodextrin was prepared using saturated solution method and high performance liquid chromatoThis study was designed to investigate the formation and effect of inclusion complex of Avermectin-β-cyclodextrin based on the accommodation property of β-cyclodextrins molecular cavity. The inclusion complex of Avermectin-β-cyclodextrin was prepared using saturated solution method and high performance liquid chromatography (HPLC) was employed to determine its entraping efficiency. The formation of Avermectin-β-cyclodextrin inclusion complex was also demonstrated by infrared spectroscopy(IR). The change of chemical structure produced by photocatalysis of Abamectin was analyzed and the effect of inclusion complex to strengthen the photolysis stability of Abamectins chemical structure was studied. The results show that the entraping efficiency of the inclusion complex was 40.5%. The IR analysis presents that the intermolecular hydrogen bond was formed in the Avermectin-β-cyclodextrin inclusion complex, indicating the composition effect was different from physical mixture. The lactones structure of Avermectin B1a can be photodecomposed and disrupted. After decomposition, the infrared stretching vibration peak of C—O—C structure disappeared and the lactone bond was significantly broken. The lactones structure of avermectin B1a was covered by the inclusion molecular loci in β-cyclodextrin after the formation of avermectin-β-cyclodextrin inclusion complex, providing a good photophobic protection for C—O—C structure in the macrocyclic lactone structure of avermectin B1a and improving the photostability of avermectin B1a molecule. The innovation of this study is that the structure and the characters of the prepared avermectin-β-cyclodextrin inclusion complex were analyzed using spectrum methods. This inclusion complex is expected to be the ideal intermediate in the construction of protective controlled release formulation of avermectin..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1201 (2014)
The Unique Reflection Spectra and IR Characteristics of Golden-Color Seawater Cultured Pearl
YAN Jun, TAO Jin-bo, DENG Xiao-qiong, HU Xian-chao, and WANG Xiao-xiang
A comparative study on the natural-color golden seawater cultured pearls and the treated-color golden seawater cultured pearls were carried out by UV-Vis reflectance spectra. Furthermore, the frequency variations of ν3, ν1, ν2 and ν4 bands of the aragonites (a crystal form of calcium carbonate) with the positions of naA comparative study on the natural-color golden seawater cultured pearls and the treated-color golden seawater cultured pearls were carried out by UV-Vis reflectance spectra. Furthermore, the frequency variations of ν3, ν1, ν2 and ν4 bands of the aragonites (a crystal form of calcium carbonate) with the positions of nacreous layer and nucleus in natural or treated-color golden-color seawater cultured pearls were firstly systematically measured. The results showed that: (1) based on the results of UV-Vis reflectance spectra of natural or treated-color golden seawater cultured pearls, interestingly, it was firstly found that the natural-color golden one displays slight varied UV-Vis reflection spectra because of its different surface microstructure located on the outer nacreous layer. Meanwhile, according to the characteristic of UV-Vis reflectance spectra of treated-color golden ones, the treated-color ones were firstly classified to four categories. (2) The frequency of ν2 band of aragonite in nacreous layer of natural-color or treated-color golden pearls was greater than the other one from theirs corresponding nucleus, namely A clear blue shift was observed in the former. But the other bands were not altered in the positions of nacreous layer and nucleus, and had the same valves with synthetic aragonites. Additionally, the location of absorption bands of aragonite in nacreous layer of natural or treated-color golden pearls had no frequency shift, which indicates that the behavior of color-treating had no effect on the crystal structure of golden pearls..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1206 (2014)
Identification of Vibration Characteristics in Infrared Spectrum of Polybrominated Diphenyl Ethers Congeners Based on Br Substituents
JIANG Long, WEN Jing-ya, and LI Yu
Structure optimization and frequency calculations of 209 kinds of PBDEs homologues were carried out at the B3LYP/6-31G(d) level based on density functional theory, the known experimental parameters of 4 PBDEs congeners were compared with the calculated values, and the average analog coefficient was 0.989. The main vibrStructure optimization and frequency calculations of 209 kinds of PBDEs homologues were carried out at the B3LYP/6-31G(d) level based on density functional theory, the known experimental parameters of 4 PBDEs congeners were compared with the calculated values, and the average analog coefficient was 0.989. The main vibration of DE and BDE-209 which contained only H atoms or Br substituent in the benzene ring was assigned due to their less interference for various infrared spectrum vibrations. C-Br bond vibration which was often coupled with other forms of vibration was not easy to distinguish between PBDEs congeners. With the characteristics of universality, strong vibration and identifiable, triangular breathing vibration of the benzene rings in the infrared spectrum was selected as a characteristic vibration among different PBDEs homologues, the analysis results showed that the ortho-substituted and para-substituted Br could significantly improve the vibration frequency of triangular breathing vibration, while the meta-substituted Br played the opposite role; For the low bromide, the more the substituents in ortho position, the higher the frequency, while for the high bromide homologues, simultaneous existence in ortho-position and para-position would have a higher frequency; With the same substituted location, the more the substituent in the same benzene ring, the higher the vibration frequency. SVM regression model was used to verify the relative relationship between Br substituent and triangle breathing vibration frequency of the benzene rings, and the simulation efficiency coefficient of model was 0.956. The study provided a theoretical basis and guidance for actually testing and identifying PBDEs homologues in the environment..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1211 (2014)
Study on Dendrobium Loddigesii Rolfes from Different Regions and Harvest Periods by FTIR
LIU Wen-jie, SUN Zhi-rong1, XU Chang-hua, SUN Su-qin, WEI Xin-xin, CHEN Long, and DU Yuan
Infrared Spectroscopy (IR) integrated with two dimensional correlation infrared spectroscopy (2DCOS IR) was employed to rapidly discriminate Dendrobium loddigesii Rolfes (DR) from different regions and harvesting periods. The results showed that the IR peaks around 1 035, 1 051, 1 078, 1 156, 1 500, 1 511 and 1 736 cm-Infrared Spectroscopy (IR) integrated with two dimensional correlation infrared spectroscopy (2DCOS IR) was employed to rapidly discriminate Dendrobium loddigesii Rolfes (DR) from different regions and harvesting periods. The results showed that the IR peaks around 1 035, 1 051, 1 078, 1 156, 1 500, 1 511 and 1 736 cm-1 had perceptible differences among DRs from different regions, indicating that different DRs containing remarkable different compositions and contents of polysaccharides, ketones and esters. 2DCOS IR spectra of DRs from Vietnam, Yunnan, Guangxi, Guizhou each had seven, eight, eight, nine auto peaks, respectively; furthermore, DRs from Guagnxi had the strongest peak in 1 220 cm-1, which was distinguish to those of other DRs (980 cm-1). In the IR spectra of DRs from different harvest seasons, the wave number of key peaks in (1 034～1 023)cm-1, the wave number of minor peaks in (1 617±4)cm-1, as well as the presence of peaks in 1 078(1 076, 1 079)cm-1, showed obvious periodic changes with the seasons, which indicated the accumulation of polysaccharides and ketones from DRs displayed an evident periodic variability discipline. The application of FTIR in DRs could facilitate acquiring their growth conditions, composition and content changes, which would be significant in rational exploitations and utilizations of DR..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1217 (2014)
Research Progress in Using Near Infrared for Monitoring Drug Quality in Domestic Circulation
FENG Yan-chun, and HU Chang-qin
Drugs are special goods that are directly related to public health, so their quality should be monitored in any link of their whole lifecycle. With nondestructive, rapid and environmentally friendly characteristics, near infrared technique is highly suitable for monitoring drug quality in the open market as well as theDrugs are special goods that are directly related to public health, so their quality should be monitored in any link of their whole lifecycle. With nondestructive, rapid and environmentally friendly characteristics, near infrared technique is highly suitable for monitoring drug quality in the open market as well as the distribution channels. The present paper reviewed the current situation (analytical objects, methods and instruments) about the application of near infrared spectroscopy in monitoring the quality of the final drug products, Chinese crude drug or decoction pieces in domestic circulation since 1997, expounded the unsolved problems and future prospects..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1222 (2014)
In Situ IR Study of Surface Hydroxyl and Photocatalytic Oxidation of Toluene of Rutile TiO2
LIN Hua-xiang, DENG Wei-hua, LONG Jin-lin, and WANG Xu-xu
In the present work, the surface hydroxyls on rutile TiO2 that evacuated at different temperature were characterized by in suit FTIR. The action of OH groups in photocatalytic reaction was tested by adsorption and photooxidation of toluene in an in situ IR cell. The results show that there are seven OH groups(with bandIn the present work, the surface hydroxyls on rutile TiO2 that evacuated at different temperature were characterized by in suit FTIR. The action of OH groups in photocatalytic reaction was tested by adsorption and photooxidation of toluene in an in situ IR cell. The results show that there are seven OH groups(with bands at 3 724, 3 700, 3 652, 3 648, 3 610, 3 413 and 3 362 cm-1) on rutile TiO2 with different thermal stability. Among the seven hydroxyl groups, the OH groups with bands at 3 724, 3 700 and 3 652 cm-1 are thermal stable and are ascribed to isolate hydroxyl groups, while the OH groups with bands at 3 648, 3 610, 3 413 and 3 362 cm-1 are thermal unstable that almost disappear after evacuation at 250 ℃. During the adsorption of toluene, only the surface hydroxyls with bands 3 648, 3 610 and 3 652 cm-1 act as adsorption sites for adsorption of toluene..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1229 (2014)
Study on Infrared Spectroscopy of Cationic Polyacrylamide Initiated by Ultraviolet
SUN Yong-jun, LIANG Jian-jun, ZHENG Huai-li, ZHU Chuan-jun, HU Xue-bin, FAN Wei, LIAO Yi, and XUE Wen-wen
Cationic Polyacrylamide P(AM-DAC-BA) was synthesized by UV initiation, with acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC), butyl acrylate (BA) as the monomers. P(AM-DAC-BA). UV spectroscopy and infrared spectroscopy were employed to study the structural characteristics. Attributions of typical infCationic Polyacrylamide P(AM-DAC-BA) was synthesized by UV initiation, with acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC), butyl acrylate (BA) as the monomers. P(AM-DAC-BA). UV spectroscopy and infrared spectroscopy were employed to study the structural characteristics. Attributions of typical infrared vibrational frequencies in AM/DAC/BA/P(AM-DAC-BA) were analysed. By comparing with infrared spectroscopy of the monomers, symmetrical characteristic of P(AM-DAC-BA) increasesd, and the infrared spectroscopy of polymerization product was simpler. The intrinsic viscosity increased with the increase in light intensity, BA content, photoinitiator concentration and illumination time. The groups of —CONH2, —COOCH2(CO), —COOCH2—(C—O—C), —CH2—N(CH3)3 group in AM, DAC, BA were selected as characteristic absorption peaks for studying. With the increase in light intensity and BA content, the characteristic peak areas increased. With the increase in photoinitiator concentration, the characteristic peak areas decreased. The characteristic peak areas decreased firstly and then increased with increasing the illumination time. But the corresponding characteristic IR absorption peaks of P(AM-DAC-BA) were similar, and the positions of characteristic peaks were basically the same..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1234 (2014)
Analysis of the Effect of Moisture on Soil Spectra Detection by Using Two-Dimensional Correlation Near Infrared Spectroscopy
SONG Hai-yan, and CHENG Xu
In order to analyze the effects of moisture on soil spectra detection, soil samples from three different places (Taoyuanbao, Muchang, and Shanxi agricultural university) were collected. All soil samples were sieved, dried and prepared with different water content (20%, 15%and 10%). The spectra of soil samples with diffIn order to analyze the effects of moisture on soil spectra detection, soil samples from three different places (Taoyuanbao, Muchang, and Shanxi agricultural university) were collected. All soil samples were sieved, dried and prepared with different water content (20%, 15%and 10%). The spectra of soil samples with different water content were collected by ASD FieldSpec3. Finally, moisture was looked as the the external disturbance, and two-dimensional correlation near-infrared spectroscopy (2D-NIR) technique was applied to analyze the effect of moisture on soil spectra detection. 2D-NIR analysis was realized by using shige software (2Dshige shigeaki Morita, Kwansei-Gakuin University).The results showed that, the sensitive bands of moisture in 2D-NIR spectra were more obvious than one-dimensional spectra. In the region 350～2 500 nm, the synchronous spectra of soil samples from different places were similar. Two automatic peaks near 2 210 and 1 929 nm were strong, and one automatic peak near 1 415 nm was weak. Moreover, the peak 1 929 nm was most sensitive to moisture content, next was 2 210 nm, and the last one was 1 415 nm. The sensitive bands and sensitive degree were pointed out in this research. It will be helpful for anti moisture model building..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1240 (2014)
Research on Concentration Retrieval of Gas FTIR Spectra by Interval Extreme Learning Machine and Genetic Algorithm
CHEN Yuan-yuan, WANG Zhi-bin, WANG Zhao-ba, and LI Xiao
This paper proposed a novel effective quantitative analysis method for FTIR spectroscopy of polluted gases, which select the best wavenumbers based on the idea of interval dividing. Meanwhile, genetic algorithm was adopted to optimize the connect weights and thresholds of the input layer and the hidden layer of extremeThis paper proposed a novel effective quantitative analysis method for FTIR spectroscopy of polluted gases, which select the best wavenumbers based on the idea of interval dividing. Meanwhile, genetic algorithm was adopted to optimize the connect weights and thresholds of the input layer and the hidden layer of extreme learning machine (ELM) because of its global search ability. Firstly, the whole spectrum region was divided into several subintervals; Secondly, the quantitative analysis model was established in each subinterval by using optimized GA-ELM; Thirdly, the best combination of subintervals was selected according to the generalized performance of each subinterval model by computing the parameters root mean square error (RMSE) and determined coefficients r. In this paper, the mixture of CO, CO2 and N2O gases were selected as the research object and the whole spectrum range was from 2 140 to 2 220 cm-1. The experiment results showed that the RMSE of model established with the selected wavenumbers was 154.996 3, the corresponding r can reach 0.987 4, and the running time was just 0.8 seconds, which indicated that the concentration retrieval model established with the proposed Interval-GA-ELM (iGELM) method can not only reduce the modeling time, but also can improve the stability and predict accuracy, especially under the condition of the exist of interferents, which providing an effective approach to the remote analysis of polluted gases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1244 (2014)
Remote System of Natural Gas Leakage Based on Multi-Wavelength Characteristics Spectrum Analysis
LI Jing, LU Xu-tao, and YANG Ze-hui
In order to be able to quickly, to a wide range of natural gas pipeline leakage monitoring, the remote detection system for concentration of methane gas was designed based on static Fourier transform interferometer. The system used infrared light, which the center wavelength was calibrated to absorption peaks of methanIn order to be able to quickly, to a wide range of natural gas pipeline leakage monitoring, the remote detection system for concentration of methane gas was designed based on static Fourier transform interferometer. The system used infrared light, which the center wavelength was calibrated to absorption peaks of methane molecules, to irradiated tested area, and then got the interference fringes by converging collimation system and interference module. Finally, the system calculated the concentration-path-length product in tested area by multi-wavelength characteristics spectrum analysis algorithm, furthermore the inversion of the corresponding concentration of methane. By HITRAN spectrum database, Selected wavelength position of 1.65 μm as the main characteristic absorption peaks, thereby using 1.65 μm DFB laser as the light source. In order to improve the detection accuracy and stability without increasing the hardware configuration of the system, solved absorbance ratio by the auxiliary wavelength, and then get concentration-path-length product of measured gas by the method of the calculation proportion of multi-wavelength characteristics. The measurement error from external disturbance is caused by this innovative approach, and it is more similar to a differential measurement. It will eliminate errors in the process of solving the ratio of multi-wavelength characteristics, and can improve accuracy and stability of the system. The infrared absorption spectrum of methane is constant, the ratio of absorbance of any two wavelengths by methane is also constant. The error coefficients produced by the system is the same when it received the same external interference, so the measured noise of the system can be effectively reduced by the ratio method. Experimental tested standards methane gas tank with leaking rate constant. Using the tested data of PN1000 type portable methane detector as the standard data, and were compared to the tested data of the system, while tested distance of the system were 100, 200 and 500 m. Experimental results show that the methane concentration detected value was stable after a certain time leakage, the concentration-path-length product value of the system was stable. For detection distance of 100 m, the detection error of the concentration-path-length product was less than 1.0%. With increasing distance from tested area, the detection error is increased correspondingly. When the distance was 500 m, the detection error was less than 4.5%. In short, the detected error of the system is less than 5.0% after the gas leakage stable, to meet the requirements of the field of natural gas leakage remote sensing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1249 (2014)
Near Infrared Spectroscopy Analysis Method of Maize Hybrid Seed Purity Discrimination
HUANG Hua-jun, YAN Yan-lu, SHEN Bing-hui, LIU Zhe, GU Jian-cheng, LI Shao-ming, ZHU De-hai, ZHANG Xiao-dong, MA Qin, LI Lin, and AN Dong
Near infrared spectroscopy analysis method of discrimination of maize hybrid seed purity was studied with the sample of Nong Hua 101 (NH101) from different origins and years. Spectral acquisition time lasted for 10 months. Using Fourier transform (FT) near infrared spectroscopy instruments, including 23 days in differeNear infrared spectroscopy analysis method of discrimination of maize hybrid seed purity was studied with the sample of Nong Hua 101 (NH101) from different origins and years. Spectral acquisition time lasted for 10 months. Using Fourier transform (FT) near infrared spectroscopy instruments, including 23 days in different seasons (divided into five time periods), a total of 920 near infrared diffuse reflectance spectra of single corn grain of those samples were collected. Moving window average, first derivative and vector normalization were used to pretreat all original spectra, principal component analysis (PCA) and linear discriminant analysis (LDA) were applied to reduce data dimensionality, and the discrimination model was established based on biomimetic pattern recognition (BPR) method. Spectral distortion was calibrated by spectra pretreatment, which makes characteristics spatial distribution range of sample spectra set contract. The relative distance between hybrid and female parent increased by nearly 70-fold, and the discrimination model achieved the identification of hybrid and female parent seeds. Through the choice of representative samples, the model's response capacity to the changes in spectral acquisition time, place and environment, etc. was improved. Besides, the model's response capacity to the changes in time and site of seed production was also improved, and the robustness of the model was enhanced. The average correct acceptance rate (CAR) of the test set reached more than 95% while the average correct rejection rate (CRR) of the test set also reached 85%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1253 (2014)
Rapid Identification of Coix Seed Varieties by Near Infrared Spectroscopy
LIU Xing, MAO Dan-zhuo, WANG Zheng-wu, and YANG Yong-jian
Unsupervised learning algorithm-principal component analysis (PCA), and supervised learning algorithm-learning vector quantization (LVQ) neural network and support vector machine (SVM) were used to carry out qualitative discriminant analysis of different varieties of coix seed from different regions. Since nutrient comUnsupervised learning algorithm-principal component analysis (PCA), and supervised learning algorithm-learning vector quantization (LVQ) neural network and support vector machine (SVM) were used to carry out qualitative discriminant analysis of different varieties of coix seed from different regions. Since nutrient compositions of different varieties coix seed samples from different origins were complex and the contents were similar, characteristic variables of two kinds of coix seed were alike, the scores plot of their principal components seriously overlapped and the categories of coix seed were difficult to distinguish. While satisfactory results were obtained by LVQ neural network and SVM. The accuracy of LVQ neural network prediction is 90.91%, while the classification accuracy of SVM, whose penalty parameter and kernel function parameter were optimized, can be up to 100%. The results show that NIRS combined with chemometrics can be used as a rapid, nondestructive and reliable method to identify coix seed varieties and provide technical reference for market regulation..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1259 (2014)
Near-Infrared Hyperspectral Imaging Combined with CARS Algorithm to Quantitatively Determine Soluble Solids Content in “Ya” Pear
LI Jiang-bo, PENG Yan-kun, CHEN Li-ping, and HUANG Wen-qian
The present study proposed competitive adaptive reweighted sampling (CARS) algorithm to be used to select the key variables from near-infrared hyperspectral imaging data of “Ya” pear. The performance of the developed model was evaluated in terms of the coefficient of determination（r2）, and the root mean square error ofThe present study proposed competitive adaptive reweighted sampling (CARS) algorithm to be used to select the key variables from near-infrared hyperspectral imaging data of “Ya” pear. The performance of the developed model was evaluated in terms of the coefficient of determination（r2）, and the root mean square error of prediction (RMSEP) and the ratio (RPD) of standard deviation of the validation set to standard error of prediction were used to evaluate the performance of proposed model in the prediction process. The selected key variables were used to build the PLS model, called CARS-PLS model. Comparing results obtained from CARS-PLS model and results obtained from full spectra PLS, it was found that the better results (r2pre=0.908 2, RMSEP=0.312 0 and RPD=3.300 5) were obtained by CARS-PLS model based on only 15.6% information of full spectra. Moreover, performance of CARS-PLS model was also compared with PLS models built by using variables got by Monte Carlo-uninformative variable elimination (MC-UVE) and genetic algorithms (GA) method. The result found that CARS variable selection algorithm not only can remove the uninformative variables in spectra, but also can reduce the collinear variables from informative variables. Therefore, this method can be used to select the key variables of near-infrared hyperspectral imaging data. This study showed that near-infrared hyperspectral imaging technology combined with CARS-PLS model can quantitatively predict the soluble solids content (SSC) in “Ya” pear. The results presented from this study can provide a reference for predicting other fruits quality by using the near-infrared hyperspectral imaging..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1264 (2014)
Discrimination of Polysaccharides from Angelica Sinensis and Its Different Processed Products Based on Fourier Transform Infrared Spectroscopy
JI Peng, WEI Yan-ming, HUA Yong-li, and ZHANG Wen-quan
A new rapid and nondestructive method for identifying polysaccharides from Angelica sinensis and its different processed products was developed, and this method was based on Fourier transform infrared spectroscopy (FTIR). In the clinic of traditional Chinese medicine, unprocessed Angelica sinensis(UAS) is of ten used aA new rapid and nondestructive method for identifying polysaccharides from Angelica sinensis and its different processed products was developed, and this method was based on Fourier transform infrared spectroscopy (FTIR). In the clinic of traditional Chinese medicine, unprocessed Angelica sinensis(UAS) is of ten used after processed, the common processed products are Angelica sinensis parched with wine(WAS), Angelica sinensis parched with soil(SAS), Angelica sinensis parched with oil(OAS) and Charred Angelica sinensis(CAS). In order to use polysaccharides from Angelica sinensis and its processed products effectively and reasonably in clinic, it is very necessary to identify them. FTIR of polysaccharides from Angelica sinensis and its different processed products was determined, and then it was decomposed by discrete wavelet transform (DWT). The high frequency information in scale 2, 3 and 4 was selected as feature information, from which the each wavelet entropy was extracted as characteristic value. BP neural network was trained with these characteristic values. The trained BP neural network was used to identify polysaccharides from Angelica sinensis and its different processed products. According to 30 prediction samples, the correct rate for recognition was 93.3%, which indicates that: it has better feasibility to identify polysaccharides from Angelica sinensis and its different processed products by this method, which is based on FTIR, discrete wavelet transform and BP neural network..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1270 (2014)
Resonance Raman Spectra of Linear Polymer Molecule
ZHANG Xue, SUN Mei-jiao, LI Shuo, LIU Tie-cheng, SUN Cheng-lin, and LI Zuo-wei
The present paper summarizes the characteristics of resonance Raman spectra of the linear polymer molecule, and its relations with the molecular structure, including: electronic spectra(ultraviolet-visible absorption spectrum), Raman spectra characteristics and its relations with external field; Modulation relation betThe present paper summarizes the characteristics of resonance Raman spectra of the linear polymer molecule, and its relations with the molecular structure, including: electronic spectra(ultraviolet-visible absorption spectrum), Raman spectra characteristics and its relations with external field; Modulation relation between the electron energy gap and CC atom vibration; Several experimental results were obtained: The UV-visible absorption spectra are red-shifted with decreasing temperature, increasing solvent density and reducing solution concentration, and because the linear polymer molecule has high structured order, decreasing π electron energy gap; extended π electronic delocalization, large effective conjugation length, large intensity of the Raman activity, Raman spectrum are red-shifted, with large scattering cross section. “Amplitude modes” are the ideal theory models to study the linear polymer molecule..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1275 (2014)
Raman Spectra of Single Human Living Erythrocyte with the Effect of pH and Serum Albumin
WU Zheng-jie, WANG Cheng, LIN Zheng-chun, and JIAO Qing-ze
In the present work, a cell environment which mimicked the real body environment according to the concentration radio between serum albumin and hemoglobin was built, and the cell morphology, the membrane deformation capacity, and the structure of intracellular hemoglobin of single human living erythrocyte under the effIn the present work, a cell environment which mimicked the real body environment according to the concentration radio between serum albumin and hemoglobin was built, and the cell morphology, the membrane deformation capacity, and the structure of intracellular hemoglobin of single human living erythrocyte under the effect of pH and serum albumin were studied. It was found that at different suspension pH, the magnitude of variations in cell shape and membrane deformation capacity changes with the structural changes of the intracellular hemoglobin. At pH 4.14, 4.76 and 10.18, the loss of helical structure for hemoglobin, exposing of the hydrophobic amino acid in the globin chains, and changing of the combination of heme and globin, would completely destroy the stability of hemoglobin’s structure, which seriously changes RBC’s morphology and membrane deformation capacity. While at pH 6.51 and 7.80, the Raman spectra of erythrocytes are found to have no such changes, indicating that the structure of intracellular hemoglobin was not varied, thus the cell morphology and membrane deformation capacity are quite close to the normal values. At pH 5.49 and 8.76, RBC’s morphology and membrane deformation capacity have different degrees of variation, but the structure of intracellular hemoglobin has not changed, suggesting that the cell morphology and membrane deformation capacity may be reversible. The results suggest that in the suspension solution containing serum albumin, erythrocytes have better ability to regulate and control the variation of the extracellular pH. In summary, upon building an environment which contains the same concentration radio of serum albumin to hemoglobin in the blood, this work performed systematic studies on the effect of pH on human erythrocytes. It can not only help to solve the problems about the mechanism of the structural and functional changes of erythrocytes induced by environmental pH, but also elucidates the possible variation of the erythrocyte under different pathologic states. It is therefore significant for the prevention and treatment of some diseases..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1279 (2014)
SERS Spectrum Recognition for Malachite Green Real-Time Detection in Aquaculture Used Seawater
GUO Shu-xia, ZHANG Feng-ling, GAO Pan, ZENG Yong-ming, CHEN Hong-ju, LIU Guo-kun, and WANG Lei
Surface enhanced Raman spectroscopy (SERS) is a useful chemical analysis technique for its high sensitivity, which was used for Malachite Green qualitative analysis in real cases in the present article. Automatic recognition algorithms were put forward, which is a combination of three modules, including a robust FourieSurface enhanced Raman spectroscopy (SERS) is a useful chemical analysis technique for its high sensitivity, which was used for Malachite Green qualitative analysis in real cases in the present article. Automatic recognition algorithms were put forward, which is a combination of three modules, including a robust Fourier transform for background rejection, a principal component analysis based character extraction method and artificial neural networks for classifying. Low-frequency background was rejected by iterative Fourier transform in order to eliminate the effect of variable background. The best principal component combination was obtained according to the Euclidean distances between-class and within-class in the sample space. And a three-layer back-propagating neural network was constructed for classifying. As it was shown, it would both minimize the network and reduce the classifying mistakes from variable baseline and Raman characters of other substances in seawater with best principal component combination. Malachite Green real-time detection in aquaculture used seawater was realized with a lower density limit of 0.1 μg·L-1. Moreover, the method proposed in this article could be extended for other sol analysis based on SERS technique..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1284 (2014)
Preparation of Nanoparticles-Modified Silica Monolith for on-Column Surface Enhanced Raman Spectroscopy
LIU Chan, CHEN Lei, REN Hua-hua, and ZHOU Ji
A novel silica monolith modified with Ag/Au nanoparticles was prepared for the on-column surface enhanced Raman spectroscopy (SERS). The bare monolithic silica column was prepared from in-situ co-condensation of tetraethoxysilane (TMOS) and methyl trimethoxysilane (MTMS) in the presence of polyethylene glycol (PEG) viaA novel silica monolith modified with Ag/Au nanoparticles was prepared for the on-column surface enhanced Raman spectroscopy (SERS). The bare monolithic silica column was prepared from in-situ co-condensation of tetraethoxysilane (TMOS) and methyl trimethoxysilane (MTMS) in the presence of polyethylene glycol (PEG) via a sol-gel process in the capillary, and was chemically modified with (3-mercaptopropyl) trimethoxysilane (MTPMS), followed by immobilization of Ag/Au nanoparticles. Transmission electron microscopy (TEM) and UV-Vis spectrometer were used to collect the TEM images and the extinction spectra of the nanoparticles colloid, respectively. Scanning electron microscope (SEM) was utilized to record the morphology of the silica monolith. The authros used p-aminothiophenol (PATP) as a probing molecule, and the SERS effect was investigated on Au/Ag nanoparticle-modified silica monolith under the excitation line of 633 and 532 nm, respectively. It is concluded that nanoparticle-modified silica monoliths will have broad application to the on-site detection of food and water contaminants in the field..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1289 (2014)
Derivative Synchronous Fluorimetry for Determination of Synthetic Food Dyes in Food
XIE Zhi-hai, WANG Ling-yan, LIU Yu, CAI Qing, WANG Hai-li, and YAN Hong-tao
The first order derivative synchronous fluoremetry was proposed for simultaneous determination of sunset yellow and ponceau 4R. The effect of different experimental conditions, such as different pH for character of fluorescence spectra and the choosing of the optimal wavelength difference were studied. It was showed thThe first order derivative synchronous fluoremetry was proposed for simultaneous determination of sunset yellow and ponceau 4R. The effect of different experimental conditions, such as different pH for character of fluorescence spectra and the choosing of the optimal wavelength difference were studied. It was showed that the zero-crossing points were at 313.6 nm for ponceau 4R and at 302.8 nm for sunset yellow in first order derivative synchronous fluorescence spectra. Therefore, 313.6 and 302.8 nm were selected for the determination of sunset yellow and ponceau 4R when Δλ=130 nm. This method could minimize interference without preseparation. The linear ranges of sunset yellow and ponceau 4R were from 0.1 to 2.0 mg·L-1 and from 0.1 to 4.0 mg·L-1 with correlation coefficient 0.996 6 and 0.999 2, the detection limits were 0.041 and 0.019 mg·L-1, RSDs were 4.6% and 4.8% (n=6), respectively. The recoveries varied from 91.0% to 110%. The proposed method was successfully applied in simultaneous determination of sunset yellow and Ponceau 4R in food..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1293 (2014)
UV-Vis Spectrum Characteristics of Phycocyanin in Water from Taihu Lake
ZHANG Jing, WEI Yu-chun, WANG Guo-xiang, CHENG Chun-mei, and XIA Xiao-rui
The present paper analyzed the UV-Vis spectrum characteristics of phycocyanin extracted from 75 water samples around Meiliang Bay of Taihu Lake, China in spring, summer and autumn, 2011, taking standard sample of phycocyanin, Microcystic aeruginosa and Anabaena cultured indoor as the reference, and discussed the differThe present paper analyzed the UV-Vis spectrum characteristics of phycocyanin extracted from 75 water samples around Meiliang Bay of Taihu Lake, China in spring, summer and autumn, 2011, taking standard sample of phycocyanin, Microcystic aeruginosa and Anabaena cultured indoor as the reference, and discussed the difference and relation of spectrum among water samples, standard sample and single algae samples. According to the number of absorption peak in the wavelength range from 500 to 700 nm, phycocyanin spectrum of water sampling in Taihu Lake can be divided into three patterns: no peak, single peak and two peaks. In the first pattern, the absorbance changed smoothly and no absorption peak was observed around 620 nm. Depending on the absorption difference in the wavelength range from 300 to 450 nm, this pattern can be divided into type Ⅰ and type Ⅱ. Type Ⅰ only had a absorption peak near 260 nm, with the similar spectrum of chromophoric dissolved organic matter (CDOM) in the wavelength range from 250 to 800 nm. Type Ⅱ had absorption peak respectively near 260 and 330 nm. In single peak pattern and two peaks pattern, significant absorption peak of phycocyanin appeared around 620 nm. Compared to the other patterns, single peak pattern was more similar to that of standard sample and single algae samples, but different in their maximum absorption peaks position and relative absorption intensity in the wavelength range of 250~300, 300~450 and 500~700 nm, because of different algae species and purity after extraction . In the two peaks pattern, another absorption peak appeared at 670nm, with the absorption shoulder from 350 to 450 nm, and shared the absorption characteristics of phycocyanin and chlorophyll complex protein. The research can provide a basic support for the phycocyanin quantitation and blooms monitoring in Taihu Lake..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1297 (2014)
Effect of Pressure on Electron-Phonon Coupling Constants of All-Trans-β-Carotene
SUN Mei-jiao, WANG Kai, XU Sheng-nan, QU Guan-nan, LI Shuo, SUN Cheng-lin, ZHOU Mi, and LI Zuo-wei
The present paper cited that R.Tubino and other people introduced a kind of electron-phonon coupling constants with dimension, which can establish the relation with the Huang-Rhys factor and calculate the electron-phonon coupling constants of every C—C bond vibration mode. There are many reports about the visible absorThe present paper cited that R.Tubino and other people introduced a kind of electron-phonon coupling constants with dimension, which can establish the relation with the Huang-Rhys factor and calculate the electron-phonon coupling constants of every C—C bond vibration mode. There are many reports about the visible absorption and Raman spectra of all-trans-β-carotene with pressure. But the study about the Raman scattering cross section and the Huang-Rhys factor with pressure have not been reported now. Visible absorption and Raman spectra of all-trans-β-carotene were measured in carbon disulfide in the pressure range from 0.04 to 0.60 GPa. The results indicated that the visible absorption spectra of β-carotene in nonpolar solvent carbon disulfide are red-shifted with pressure increasing, but the frequency shifts towards higher frequencies in the Raman spectra, the Raman scattering cross section decreases, Huang-Rhys factor increases, and the electron-phonon coupling constants of CC bond vibration modes increase. The mechanism is that all-trans-β-carotene caused by compression and a decrease in the structurally ordered properties of the molecules leads to narrow energy gap of the π, shortens effective conjugation length, hinders delocalization of π-electron, decreases the Raman scattering cross section, and increases the Huang-Rhys factor and the electron-phonon coupling constants..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1302 (2014)
Spectrum Similarities-Based Analysis of Spatial Difference of Snow Cover for Multi-Scale Satellite Data—a Case Study of MODIS and HJ-1B Data
LIU Yan, LI Yang, YANG Yun, and JIAN Ji
Vegetation and bare soil were collected in the areas of Miyaluo district in northwest of Sichuan province, the Qilian Mountains in Qinghai province and northern areas of Xinjiang during the years of 2007 and 2013. Then these data were converted to spectral reflectance by applying sensor response function of MODIS and HVegetation and bare soil were collected in the areas of Miyaluo district in northwest of Sichuan province, the Qilian Mountains in Qinghai province and northern areas of Xinjiang during the years of 2007 and 2013. Then these data were converted to spectral reflectance by applying sensor response function of MODIS and HJ-1B respectively within the range of visible light, near-infrared and shortwave infrared. Comprehensive analysis was made on spectral characteristics and reflectivity similarities and differences of different sensors between old and new snowmelt, under the condition of different snow depth and different snow cover. The conclusions can be drawn. That is, there exists high consistency of spectral response between new snow and dirty snow for each sensor in the visible wavelength range, also it is true for bare soil and low vegetation. However, low consistency happens to other types of snow; especially snowmelt and frozen snow. The range of NDSI is relatively stable under the condition of different snow depth for full snow cover and the trend of NDSI shows great consistency for different sensors; NDSI threshold method for monitoring snow by using MODIS and HJ-1B data showed very obvious difference in spatial scales, which is a reasonable explanation of the existence of mixed pixels..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1306 (2014)
Research on the Characteristics of Ulva. Prolifera in Shandong Peninsula During 2008—2012 Based on MODIS Data
WU Meng-quan, GUO Hao, ZHANG An-ding, JIA Li-li, XIAO Lu-xiang, and WANG Jing-pu
In the present study, the MODIS data were used to monitor the situation of Ulva. prolifera in the Shandong Peninsula waters during the period of 2008—2012.Those studies mainly calculate the area of NDVI, and get the information of the time, area , scope , floating path of Ulva. prolifera by using threshold segmentationIn the present study, the MODIS data were used to monitor the situation of Ulva. prolifera in the Shandong Peninsula waters during the period of 2008—2012.Those studies mainly calculate the area of NDVI, and get the information of the time, area , scope , floating path of Ulva. prolifera by using threshold segmentation method. The feasibility of monitoring Ulva. prolifera information based on MODIS data and the macroscopic regularity of the outburst of Ulva. prolifera was elementally studied. The results showed that Ulva. prolifera first generated in the middle of May or early June, the time, area, scope of Ulva. prolifera reached a maximum, but the relative crowding density was earlier or later when Ulva. prolifera developed into a outburst. Finally, Ulva. prolifera died away after existing for 71 days in the late July or the early August. Wholly, the floating path moved to the northwest from off the coast to offshore. Based on those aspects above, the outburst of Ulva. prolifera in 2008 and 2009 was more serious than others..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1312 (2014)
Performance Comparison of Coronene Film for UV-CCD Prepared by Spin-Coating and Physical Vapor Deposition
HE Liang, ZHANG Da-wei, TAO Chun-xian, HONG Rui-jin, and HUANG Yuan-shen
In the present paper, the methods of spin-coating and physical vapor deposition (PVD) were researched to prepare the coronene film for UV-CCD, and their properties were characterized and compared with each other. The results of the experiment show that the process of spin-coating is relatively simple, which takes advanIn the present paper, the methods of spin-coating and physical vapor deposition (PVD) were researched to prepare the coronene film for UV-CCD, and their properties were characterized and compared with each other. The results of the experiment show that the process of spin-coating is relatively simple, which takes advantage of materials and retains the inherent crystal structure of coronene. However, the roughness of the film is a little more than that of PVD method; the film prepared by PVD method can absorb ultraviolet more effectively and then emits fluorescence with more intensity. Compared with the method of spin-coating, the surface of PVD film is more smoothly, and the process of thermal evaporation changes the crystal structure of coronene and forms another new crystalline state according to the XRD graph. While the whole process of PVD is more complex and it needs larger cost of production than spin-coating method. Besides, the comparison research work provided theoretical direction for preparing the photoluminescence down-conversion film under different requirements, such as fluorescence intensity, surface roughness and cost of production..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1319 (2014)
Measurement of Multi-Wavelength Pulse Oxygen Saturation Based on Dynamic Spectroscopy
WANG Xiao-fei, and ZHAO Wen-jun
The present paper puts forward multi-wavelength pulse oxygen saturation measurement based on dynamic spectroscopy to do the non-invasive determination of oxygen saturation. Compared to conventional ways, the new method makes full use of more wavelengths light and improves the measurement accuracy. During the experimentThe present paper puts forward multi-wavelength pulse oxygen saturation measurement based on dynamic spectroscopy to do the non-invasive determination of oxygen saturation. Compared to conventional ways, the new method makes full use of more wavelengths light and improves the measurement accuracy. During the experiment, the in-vivo measurements were carried out on 60 patients and their spectroscopic data were collected by the high sensitivity type fiber optic spectrometer. Single-trial estimation method was used to extract the dynamic spectroscopy at the wavelengths of 606.44~987.55 nm. Oxygen saturation obtained from arterial blood gas analysis is regarded as the true value. Synergy interval partial least square (siPLS) was used to establish the calibration model of subjects’ oxygen saturation values against dynamic spectroscopy data. The relative error of prediction is ±0.017 6, but the relative error of the subjects in the same set measured by the patient monitor which was two-wavelength measure system is ±0.116 4. Measurement results show that the use of the high sensitivity type fiber optic spectrometer to collect multi-wavelength spectroscopic data and dynamic spectroscopy method to process data can do better in improving the accuracy of the oxygen saturation measurement..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1323 (2014)
Research on Noninvasive Risk Evaluation of Diabetes Mellitus Based on Neural Network Pattern Recognition
LI Fei, WANG Yi-kun, ZHU Ling, ZHANG Yuan-zhi, JI Min, ZHANG Long, LIU Yong, and WANG An
Advanced glycation end products (AGEs) are highly associated with hyperglycemia in human skin tissue, and they also have the autofluorescence characteristic. A self-developed optical noninvasive detection device was used to measure the autofluorescence in human skin tissue, and then a neural network pattern recognitionAdvanced glycation end products (AGEs) are highly associated with hyperglycemia in human skin tissue, and they also have the autofluorescence characteristic. A self-developed optical noninvasive detection device was used to measure the autofluorescence in human skin tissue, and then a neural network pattern recognition model was used to assess the risk of diabetes mellitus of the subject under survey. After the fluorescence spectra were acquired and processed with principal component analysis, four of the leading principal components were chosen to represent a whole spectrum. The established neural network pattern recognition model has 4 input nodes, 6 hidden nodes and 1 output node. A dataset consisting of 487 cases collected in Anhui Provincial Hospital was used to train the model. Seventy percent cases were used as the training set, 15% as the validation set and 15% as the test set. The model can output subject’s risk of diabetes mellitus, or a dichotomous judgment. Receiver operating characteristic curve can be drawn with the area under curve of 0.81, with standard error of 0.02. When using 0.5 as the threshold between diabetes mellitus and non-diabetes mellitus, the sensitivity and specificity of this model is 72.4% and 77.6% respectively, and the overall accuracy is 74.9%. The method using human skin autofluorescence spectrum combined with neural network pattern recognition model is proposed for the first time, and the results show that this method has a better screening effect compared with currently used fasting plasma glucose and HbA1c..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1327 (2014)
Maximum a Posteriori Fusion Method Based on Gradient Consistency Constraint for Multispectral/Panchromatic Remote Sensing Images
MENG Xiang-chao, SHEN Huan-feng, ZHANG Hong-yan, ZHAGN Liang-pei, and LI Hui-fang
Multispectral (MS) images with high spatial resolution (HR) can be obtained by fusing MS images and panchromatic (PAN) image, the HR MS images have an important significance in image interpretation and classification, etc. In the present paper, a new image fusion method based on gradient consistency constraint for MS/PMultispectral (MS) images with high spatial resolution (HR) can be obtained by fusing MS images and panchromatic (PAN) image, the HR MS images have an important significance in image interpretation and classification, etc. In the present paper, a new image fusion method based on gradient consistency constraint for MS/PAN images is developed. The method is based on maximum a posteriori (MAP) framework. The relationship of desired HR MS images and PAN image is formulated by gradient consistency constraint. Observation model of MS images and the Huber-Markov priori are combined to solve the fused image by gradient descent algorithm. In the proposed method, gradient consistency constraint is introduced, and defect of band number restriction is overcomed in conventional model-based fusion methods. Iterative step for every band is solved adaptively, and spectral characteristics of each band are fully taken into account, so it not only ensures the spectral information fidelity, but also improves the integration degree of spatial information of fused image. The proposed method has been tested using IKONOS and WorldView-2 images. It is compared with GS, AIHS and AMBF fusion methods from both qualitative and quantitative aspects. Experimental results show that the proposed method can better preserve spectral information while enhance spatial resolution, and it has broader applicability and better fusion result than other methods..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1332 (2014)
Research on Rapid and Quantitative Detection Method for Organophosphorus Pesticide Residue
SUN Yuan-xin, CHEN Bing-tai, YI Sen, and SUN Ming
The methods of physical-chemical inspection is adopted in the traditional pesticide residue detection, which require a lot of pretreatment processes, are time-consuming and complicated. In the present study, the authors take chlorpyrifos applied widely in the present agricultural field as the research object and proposThe methods of physical-chemical inspection is adopted in the traditional pesticide residue detection, which require a lot of pretreatment processes, are time-consuming and complicated. In the present study, the authors take chlorpyrifos applied widely in the present agricultural field as the research object and propose a rapid and quantitative detection method for organophosphorus pesticide residues. At first, according to the chemical characteristics of chlorpyrifos and comprehensive chromogenic effect of several colorimetric reagents and secondary pollution, the pretreatment of the scheme of chromogenic reaction of chlorpyrifos with resorcin in a weak alkaline environment was determined. Secondly, by analyzing Uv-Vis spectrum data of chlorpyrifos samples whose content were between 0.5 and 400 mg·kg-1, it was confirmed that the characteristic information after the color reaction mainly was concentrated among 360～400 nm. Thirdly, the full spectrum forecasting model was established based on the partial least squares, whose correlation coefficient of calibration was 0.999 6, correlation coefficient of prediction reached 0.995 6, standard deviation of calibration (RMSEC) was 2.814 7 mg·kg-1, and standard deviation of verification (RMSEP) was 8.012 4 mg·kg-1. Fourthly, the wavelengths whose center wavelength is 400 nm was extracted as characteristic region to build a forecasting model, whose correlation coefficient of calibration was 0.999 6, correlation coefficient of prediction reached 0.999 3, standard deviation of calibration (RMSEC) was 2.566 7 mg·kg-1, standard deviation of verification (RMSEP) was 4.886 6 mg·kg-1, respectively. At last, by analyzing the near infrared spectrum data of chlorpyrifos samples with contents between 0.5 and 16 mg·kg-1, the authors found that although the characteristics of the chromogenic functional group are not obvious, the change of absorption peaks of resorcin itself in the neighborhood of 5 200 cm-1 happens. The above-mentioned experimental results show that the proposed method is effective and feasible for rapid and quantitative detection prediction for organophosphorus pesticide residues. In the method, the information in full spectrum especially UV-Vis spectrum is strengthened by chromogenic reaction of a colorimetric reagent, which provides a new way of rapid detection of pesticide residues for agricultural products in the future..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1338 (2014)
Study on the Interaction of Doxycycline with Human Serum Albumin
HU Tao-ying, CHEN Lin, and LIU Ying
The present study was designed to investigate the interaction of doxycycline (DC) with human serum albumin (HSA) by the inner filter effects, displacement experiments and molecular docking methods, based on classic multi-spectroscopy. With fluorescence quenching method at 298 and 310 K, the binding constants Ka were deThe present study was designed to investigate the interaction of doxycycline (DC) with human serum albumin (HSA) by the inner filter effects, displacement experiments and molecular docking methods, based on classic multi-spectroscopy. With fluorescence quenching method at 298 and 310 K, the binding constants Ka were determined to be 2.73×105 and 0.74×105 L·mol-1, respectively, and there was one binding site between DC and HSA, indicating that the binding of DC to HSA was strong, and the quenching mechanism was a static quenching. The thermodynamic parameters (enthalpy change, ΔH and enthropy change, ΔS) were calculated to be -83.55 kJ·mol-1 and -176.31 J·mol-1·K-1 via the Vant’ Hoff equation, which indicated that the interaction of DC with HSA was driven mainly by hydrogen bonding and van der Waals forces. Based on the Fster’s theory of non-radiation energy transfer, the specific binding distance between Trp-214 (acceptor) and DC (donor) was 4.98 nm, which was similar to the result confirmed by molecular docking. Through displacement experiments, sub-domain IIA of HSA was assigned to possess the high-affinity binding site of DC. Three-dimensional fluorescence spectra indicated that the binding of DC to HSA induced the conformation change of HSA and increased the disclosure of some part of hydrophobic regions that had been buried before. The results of FTIR spectroscopy showed that DC bound to HSA led to the slight unfolding of the polypeptide chain of HSA. Furthermore, the binding details between DC and HSA were further confirmed by molecular docking methods, which revealed that DC was bound at sub-domain IIA through multiple interactions, such as hydrophobic effect, polar forces and π-π interactions. The experimental results provide theoretical basis and reliable data for the study of the interaction between small drug molecule and human serum albumin..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1343 (2014)
Measurement of Soil Organic Matter and Available K Based on SPA-LS-SVM
ZHANG Hai-liang, LIU Xue-mei, and HE Yong
Visible and short wave infrared spectroscopy (Vis/SW-NIRS) was investigated in the present study for measurement of soil organic matter (OM) and available potassium (K). Four types of pretreatments including smoothing, SNV, MSC and SG smoothing+first derivative were adopted to eliminate the system noises and external dVisible and short wave infrared spectroscopy (Vis/SW-NIRS) was investigated in the present study for measurement of soil organic matter (OM) and available potassium (K). Four types of pretreatments including smoothing, SNV, MSC and SG smoothing+first derivative were adopted to eliminate the system noises and external disturbances. Then partial least squares regression (PLSR) and least squares-support vector machine (LS-SVM) models were implemented for calibration models. The LS-SVM model was built by using characteristic wavelength based on successive projections algorithm (SPA). Simultaneously, the performance of LS-SVM models was compared with PLSR models. The results indicated that LS-SVM models using characteristic wavelength as inputs based on SPA outperformed PLSR models. The optimal SPA-LS-SVM models were achieved, and the correlation coefficient (r), and RMSEP were 0.860 2 and 2.98 for OM and 0.730 5 and 15.78 for K, respectively. The results indicated that visible and short wave near infrared spectroscopy (Vis/SW-NIRS) (325～1 075 nm) combined with LS-SVM based on SPA could be utilized as a precision method for the determination of soil properties..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1348 (2014)
Comparative Study on Remote Sensing Invertion Methods for Estimating Winter Wheat Leaf Area Index
XIE Qiao-yun, HUANG Wen-jiang, CAI Shu-hong, LIANG Dong, PENG Dai-liang, ZHANG Qing, HUANG Lin-sheng, YANG Gui-jun, and ZHANG Dong-yan
The present study aims to explore capability of different methods for winter wheat leaf area index inversion by integrating remote sensing image and synchronization field experiment. There were four kinds of LAI inversion methods discussed, specifically, support vector machines (SVM), discrete wavelet transform (DWT), The present study aims to explore capability of different methods for winter wheat leaf area index inversion by integrating remote sensing image and synchronization field experiment. There were four kinds of LAI inversion methods discussed, specifically, support vector machines (SVM), discrete wavelet transform (DWT), continuous wavelet transform (CWT) and principal component analysis (PCA). Winter wheat LAI inversion models were established with the above four methods respectively, then estimation precision for each model was analyzed. Both discrete wavelet transform method and principal component analysis method are based on feature extraction and data dimension reduction, and multivariate regression models of the two methods showed comparable accuracy (R2 of DWT and PCA model was 0.697 1 and 0.692 4 respectively; RMSE was 0.605 8 and 0.554 1 respectively). While the model based on continuous wavelet transform suffered the lowest accuracy and didn’t seem to be qualified to inverse LAI. It was indicated that the nonlinear regression model with support vector machines method is the most eligible model for estimating winter wheat LAI in the study area..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1352 (2014)
Monitoring Freeze Stress Levels on Winter Wheat from Hyperspectral Reflectance Data Using Principal Component Analysis
WANG Hui-fang, WANG Ji-hua, DONG Ying-ying, GU Xiao-he, and HUO Zhi-guo
In order to detect the freeze injury stress level of winter wheat growing in natural environment fast and accurately, the present paper takes winter wheat as experimental object. First winter wheat canopy hyperspectral data were treated with resampling smooth. Second hyperspectral data were analyzed based on principal In order to detect the freeze injury stress level of winter wheat growing in natural environment fast and accurately, the present paper takes winter wheat as experimental object. First winter wheat canopy hyperspectral data were treated with resampling smooth. Second hyperspectral data were analyzed based on principal components analysis (PCA), a freeze injury inversion model was established, stems survival rate was dependent, and principal components of spectral data were chosen as independent variables. Third, the precision of the model was testified. The result showed that the freeze injury inversion model based on 6 principal components can estimate the winter wheat freeze injury accurately with the coefficient of determination (R2) of 0.697 5, root mean square error (RMSE) of 0.184 2, and the accuracy of 0.697 5. And the model was verified. It can be concluded that the PCA technology has been shown to be very promising in detecting winter wheat freeze injury effectively, and provide important reference for detecting other stress on crop..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1357 (2014)
Different Wavelengths Selection Methods for Identification of Early Blight on Tomato Leaves by Using Hyperspectral Imaging Technique
CHENG Shu-xi, XIE Chuan-qi, WANG Qiao-nan, HE Yong*, and SHAO Yong-ni
Identification of early blight on tomato leaves by using hyperspectral imaging technique based on different effective wavelengths selection methods (successive projections algorithm, SPA; x-loading weights, x-LW; gram-schmidt orthogonalization, GSO) was studied in the present paper. Hyperspectral images of seventy healIdentification of early blight on tomato leaves by using hyperspectral imaging technique based on different effective wavelengths selection methods (successive projections algorithm, SPA; x-loading weights, x-LW; gram-schmidt orthogonalization, GSO) was studied in the present paper. Hyperspectral images of seventy healthy and seventy infected tomato leaves were obtained by hyperspectral imaging system across the wavelength range of 380～1023 nm. Reflectance of all pixels in region of interest (ROI) was extracted by ENVI 4.7 software. Least squares-support vector machine (LS-SVM) model was established based on the full spectral wavelengths. It obtained an excellent result with the highest identification accuracy (100%) in both calibration and prediction sets. Then, EW-LS-SVM and EW-LDA models were established based on the selected wavelengths suggested by SPA, x-LW and GSO, respectively. The results showed that all of the EW-LS-SVM and EW-LDA models performed well with the identification accuracy of 100% in EW-LS-SVM model and 100%, 100% and 97.83% in EW-LDA model, respectively. Moreover, the number of input wavelengths of SPA-LS-SVM, x-LW-LS-SVM and GSO-LS-SVM models were four (492, 550, 633 and 680 nm), three (631, 719 and 747 nm) and two (533 and 657 nm), respectively. Fewer input variables were beneficial for the development of identification instrument. It demonstrated that it is feasible to identify early blight on tomato leaves by using hyperspectral imaging, and SPA, x-LW and GSO were effective wavelengths selection methods..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1362 (2014)
Detection of Slight Bruises on Apples Based on Hyperspectral Imaging and MNF Transform
ZHANG Bao-hua, HUANG Wen-qian, LI Jiang-bo, ZHAO Chun-jiang, LIU Cheng-liang, HUANG Dan-feng, and GONG Liang
Bruising is one of the major defects occurring on apple surface inevitably during postharvest handling and processing stage. To detect slight bruises on apples fast and efficiently, a novel bruises detection algorithm based on hyperspectral imaging and minimum noise fraction transform is proposed. First, the hyperspectBruising is one of the major defects occurring on apple surface inevitably during postharvest handling and processing stage. To detect slight bruises on apples fast and efficiently, a novel bruises detection algorithm based on hyperspectral imaging and minimum noise fraction transform is proposed. First, the hyperspectral images in the visible and near-infrared (400~1 000 nm) ranges are acquired, and MNF transform based on full ranges could obtain better detection performance compared to PCA transform; Second, five wavebands (560, 660, 720, 820 and 960 nm) are selected as the effective wavebands based on the coefficient curve of I-RELIEF method conducted on spectra extracted from intact and bruise surface; Third, the bruises detection algorithm is developed based on the effective wavebands and MNF transform method. For the investigated 40 sound samples and 40 different time stage bruise samples, the results with a 97.1% overall detection rate are got. The recognition results indicate that the proposed methods and the effective wavelengths selected in this paper are feasible and efficient. This research lays a foundation for the development of multispectral imaging system based on MNF transform for slight bruises detection on apples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1367 (2014)
Identification of Green Tea Brand Based on Hyperspectra Imaging Technology
ZHANG Hai-liang, LIU Xiao-li, ZHU Feng-le, and HE Yong
Hyperspectral imaging technology was developed to identify different brand famous green tea based on PCA information and image information fusion. First 512 spectral images of six brands of famous green tea in the 380～1 023 nm wavelength range were collected and principal component analysis (PCA) was performed with theHyperspectral imaging technology was developed to identify different brand famous green tea based on PCA information and image information fusion. First 512 spectral images of six brands of famous green tea in the 380～1 023 nm wavelength range were collected and principal component analysis (PCA) was performed with the goal of selecting two characteristic bands (545 and 611 nm) that could potentially be used for classification system. Then, 12 gray level co-occurrence matrix (GLCM) features (i.e., mean, covariance, homogeneity, energy, contrast, correlation, entropy, inverse gap, contrast, difference from the second-order and autocorrelation) based on the statistical moment were extracted from each characteristic band image. Finally, integration of the 12 texture features and three PCA spectral characteristics for each green tea sample were extracted as the input of LS-SVM. Experimental results showed that discriminating rate was 100% in the prediction set. The receiver operating characteristic curve (ROC) assessment methods were used to evaluate the LS-SVM classification algorithm. Overall results sufficiently demonstrate that hyperspectral imaging technology can be used to perform classification of green tea..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1373 (2014)
Study on SPAD Visualization of Pumpkin Leaves Based on Hyperspectral Imaging Technology
ZHAO Yan-ru, YU Ke-qiang, LI Xiao-li, and HE Yong
Visible/near-infrared (380～1 030 nm) hyperspectral imaging technique was used to realize SPAD visualization of pumpkin leaves in the present study. Downy mildew could be diagnosed rapidly according to significant positive correlation between downy mildew epidemic and chlorophyll content. Leaves uninfected and infected Visible/near-infrared (380～1 030 nm) hyperspectral imaging technique was used to realize SPAD visualization of pumpkin leaves in the present study. Downy mildew could be diagnosed rapidly according to significant positive correlation between downy mildew epidemic and chlorophyll content. Leaves uninfected and infected with different level downy mildew were used to acquire hyperspectral images and extract spectral information. Competitive adaptive reweighted sampling (CARS) was applied to select optimal wavelengths and finally 10 optimal wavelengths were obtained. Partial least squares regression (PLSR) was employed to establish SPAD prediction model. Results showed that, through the analysis of calibration of 48 samples and prediction of 23 samples, CARS-PLSR could obtain good results with RC=0.918, RMSECV=3.932; RCV=0.846, RMSECV=5.254; RP=0.881, and RMSEP=3.714. Regression model was gained based on the relationship between SPAD and spectral of pumpkin leaves. While SPAD of each pixel was calculated with PLSR regression equation, then SPAD distribution map of pumpkin was visualized using imaging processing technology. Final downy mildew infection could be diagnosed based on SPAD distribution map. This study provided a theoretical reference for effective monitoring plant growth and downy mildew epidemic..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1378 (2014)
Multi-DSP Parallel Processing Technique of Hyperspectral RX Anomaly Detection
GUO Wen-ji, ZENG Xiao-ru, ZHAO Bao-wei, MING Xing, ZHANG Gui-feng, and Lv Qun-bo
To satisfy the requirement of high speed, real-time and mass data storage etc. for RX anomaly detection of hyperspectral image data, the present paper proposes a solution of multi-DSP parallel processing system for hyperspectral image based on CPCI Express standard bus architecture. Hardware topological architecture ofTo satisfy the requirement of high speed, real-time and mass data storage etc. for RX anomaly detection of hyperspectral image data, the present paper proposes a solution of multi-DSP parallel processing system for hyperspectral image based on CPCI Express standard bus architecture. Hardware topological architecture of the system combines the tight coupling of four DSPs sharing data bus and memory unit with the interconnection of Link ports. On this hardware platform, by assigning parallel processing task for each DSP in consideration of the spectrum RX anomaly detection algorithm and the feature of 3D data in the spectral image, a 4DSP parallel processing technique which computes and solves the mean matrix and covariance matrix of the whole image by spatially partitioning the image is proposed. The experiment result shows that, in the case of equivalent detective effect, it can reach the time efficiency 4 times higher than single DSP process with the 4-DSP parallel processing technique of RX anomaly detection algorithm proposed by this paper, which makes a breakthrough in the constraints to the huge data image processing of DSP’s internal storage capacity, meanwhile well meeting the demands of the spectral data in real-time processing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1383 (2014)
Lithology Feature Extraction of CASI Hyperspectral Data Based on Fractal Signal Algorithm
TANG Chao, CHEN Jian-ping, CUI Jing, and WEN Bo-tao
Hyperspectral data is characterized by combination of image and spectrum and large data volume dimension reduction is the main research direction. Band selection and feature extraction is the primary method used for this objective. In the present article, the authors tested methods applied for the lithology feature extHyperspectral data is characterized by combination of image and spectrum and large data volume dimension reduction is the main research direction. Band selection and feature extraction is the primary method used for this objective. In the present article, the authors tested methods applied for the lithology feature extraction from hyperspectral data. Based on the self-similarity of hyperspectral data, the authors explored the application of fractal algorithm to lithology feature extraction from CASI hyperspectral data. The “carpet method” was corrected and then applied to calculate the fractal value of every pixel in the hyperspectral data. The results show that fractal information highlights the exposed bedrock lithology better than the original hyperspectral data. The fractal signal and characterized scale are influenced by the spectral curve shape, the initial scale selection and iteration step. At present, research on the fractal signal of spectral curve is rare, implying the necessity of further quantitative analysis and investigation of its physical implications..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1388 (2014)
Effects of LED Spectrum Combinations on the Absorption of Mineral Elements of Hydroponic Lettuce
CHEN Xiao-li, GUO Wen-zhong, XUE Xu-zhang, and Morewane Mmanake Beauty
Lettuce (Lactuca sativa) was hydroponically cultured in a completely enclosed plant factory, in which spectrum proportion-adjustable LED panels were used as sole light source for plant growth. Absorption and content of eleven mineral elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu, B and Mo in Lactuca sativa under diLettuce (Lactuca sativa) was hydroponically cultured in a completely enclosed plant factory, in which spectrum proportion-adjustable LED panels were used as sole light source for plant growth. Absorption and content of eleven mineral elements such as K, P, Ca, Mg, Na, Fe, Mn, Zn, Cu, B and Mo in Lactuca sativa under different spectral component conditions were studied by ICP -AES technology. The results showed that: (1) Single or combined spectrums corresponding to the absorbing peaks of chlorophyll a and b (450, 660 nm) could enhance the absorbing ability of roots especially for mineral elements Na, Fe, Mn, Cu and Mo, the single red spectrum had the most significant promoting effect under which contents of those four elements were respectively 7.8, 4.2, 4.0 and 3.7 times more than that under FL; (2) Absorption of K and B was the highest under FL which was 10.309 mg·g-1 and 32.6 μg·g-1 while the values decreased significantly under single or combined spectrum of red and blue; (3) Plants grown under single blue spectrum had the lowest absorption of Ca and Mg which respectively decreased by 35% and 33% than FL; (4) Lettuce grown under the spectrum combination of 30% blue and 70% red had the highest accumulations of biomass while those grown under 20% blue and 80% red had the highest accumulations of the following seven elements Ca, Mg, Na, Fe, Mn, Zn and B. The results provided theoretical basis for adjusting nutrient solution formula and selecting light spectrum of hydroponic lettuce..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1394 (2014)
Application of ICP-MS in the Health Risk Assessment of Heavy Metals for Drinking Water Sources in Reservoirs
GAO Bo, LI Qiang, ZHOU Huai-dong, GAO Ji-jun, ZOU Xiao-wen, and HUANG Yong
The six heavy metal concentrations (Cr, Cr, As, Cd, Cu, Zn and Pb) in water samples collected from five reservoirs of Liao River Basin were studied. The health risk assessment for heavy metals pollution in reservoirs was conducted based on the environmental health risk assessment model recommended by U. S. EnvironmentaThe six heavy metal concentrations (Cr, Cr, As, Cd, Cu, Zn and Pb) in water samples collected from five reservoirs of Liao River Basin were studied. The health risk assessment for heavy metals pollution in reservoirs was conducted based on the environmental health risk assessment model recommended by U. S. Environmental Protection Agency. The results showed that the average concentrations of Cr, Cu, Zn, As, Cd and Pb in five reservoirs of Liao River Basin were 3.36, 1.03, 2.70, 1.23, 0.02 and 0.03 μg·L-1, respectively. In fact, these heavy metals concentrations were obviously lower than the Standard of National Drinking Water in China (GB 5749—2006). The results also showed that the metal carcinogenic risk was relatively high in this region. The order of the risk level of carcinogenic metals was Cr>As>Cd. The highest carcinogenic risk was from Cr, with the risk for adults ranging from 4.50×10-5~7.53×10-5 a-1 and the risk for children ranging from 6.29×10-5 to 1.05×10-4 a-1. The health risk levels caused by non-carcinogenic metals ranging from 10-13 to 10-10 a-1 were lower than the acceptable range suggested by International Commission on Radiological Protection (ICRP) and the order of the risk level of non-carcinogenic metals was Cu>Zn>Pb. The total health risk of heavy metals for adults ranging from 1.07×10-4 to 1.72×10-4 a-1 and for children ranging from 1.49×10-4 to 2.40×10-4 a-1 exceeded the accepted level of 5×10-5 a-1 as suggested by ICRP. The health risk levels of carcinogenic metals were significantly higher than those of non-carcinogenic metals in the reservoirs for Liao River Basin..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1398 (2014)
Application of ICP-MS and AFS to Detecting Heavy Metals in Phosphorus Fertilizers
HUANG Qing-qing, LIU Xing, ZHANG Qian, QIAO Yu-hui, SU De-chun, JIANG Rong-feng, RUI Yu-kui, and LI Hua-fen
In order to investigate heavy metals in phosphorus fertilizers in China, 159 samples of phosphorus fertilizers including imported fertilizers and domestic fertilizers were collected from fertilizer markets, and the contents of heavy metals were determined by ICP-MS and AFS after microwave digestion. The results showed In order to investigate heavy metals in phosphorus fertilizers in China, 159 samples of phosphorus fertilizers including imported fertilizers and domestic fertilizers were collected from fertilizer markets, and the contents of heavy metals were determined by ICP-MS and AFS after microwave digestion. The results showed that the phosphorous fertilizers contained certain amount of heavy metals, and there was great variability in the contents of heavy metals. The mean contents of Cd, Cu, Zn, Cr, Pb, Ni, As and Hg were 0.77, 35.6, 102.7, 24.1, 16.6, 15.4, 19.4 and 0.08 mg·kg-1 fertilizer, respectively; based on the calculation of P2O5, the mean contents of above heavy metals were 4.48, 258.4, 767.4, 190.0, 151.3, 134.5, 155.8 and 8.79 mg·kg-1 P2O5, respectively. The contents of heavy metals Cd, Cr, Pb, As and Hg in the tested samples accord with the ecological index of arsenic, cadmium, lead, chromium and mercury for fertilizers (GB/T 23349-2009), with the exception of Cd in one imported sample of diammonium phosphate and As in one sample of mono-ammonium phosphate. Analyzing the contents of heavy metals in imported fertilizers, the Cd contents in imported fertilizers was ranged from 0.02 to 27.2 mg·kg-1 fertilizer, the mean and median Cd contents in imported fertilizers were 3.20 and 0.41 mg·kg-1 fertilizer, respectively. And the Cu, Cr and Hg contents in the imported fertilizers were higher than that of domestic fertilizers, the mean contents of Cu, Cr and Hg in imported fertilizers were 39.4, 26.6 and 0.47 mg·kg-1 fertilizer, respectively..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1403 (2014)
Influence of Laser Energy on Measurement of Unburned Carbon in Fly Ash Particle Flow
BAI Kai-jie, TIAN Hao-chen, YAO Shun-chun, ZHANG Bo, SHEN Yue-liang, XU Qi-sheng, and LU Ji-dong
The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laseThe fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laser in the range of 40 to 130 mJ were used to ablate the f1y ash particle flow．The results show that the carbon line intensity is increased linearly with the increases in laser energy, but the SNR of carbon line increases in the range of 40 to 90 mJ and then trends to saturation, while the elimination rate of false data decreases. In this experiment, laser energy ranging from 90 to 100 mJ can enhance the plasma emission signal and improve the true spectral data of fly ash particle flow. So laser energy has close correlations with the ablation of the particle flow and the carbon line intensity .Reasonable laser energy is good for the effective ablation of the fly ash particle flow to get plasma spectra signals with good SNR..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1407 (2014)
Study on the Solid Sorbent Tube for Capturing Mercury in the Workplace Air and Determination by Cold Vapor Atomic Absorption Spectrometry
HUANG Zhen-nong, SUN Yi, RUAN Xiao-lin, WU Bang-hua, ZHANG Ai-hua, HUANG Jun-yi, HUANG Yan-ling, and HUANG Han-lin
A new KMnO4-MnO2 solid multisorbent tube for capturing mercury in workplace air was developed. Experimental conditions for solid multisorbent tube, efficiency of sampling, desorption efficiency and stability were studied. Mercury and its compounds in air were captured by solid KMnO4-MnO2 sorbent filled tube and desorbeA new KMnO4-MnO2 solid multisorbent tube for capturing mercury in workplace air was developed. Experimental conditions for solid multisorbent tube, efficiency of sampling, desorption efficiency and stability were studied. Mercury and its compounds in air were captured by solid KMnO4-MnO2 sorbent filled tube and desorbed with 0.90 mol·L-1 sulfuric acid solution. Mercury and its compounds were quantitatively analyzed according to the method of GBZ/T 160.14—2004 cold vapor atomic absorption spectrometry. The linear range of the proposed method was 0.000 2~0.015 0 mg·L-1 with r=0.999 1, the average efficiency of sampling was 99.9%～100.0% in the concentration range of 0.001~2.820 mg·m-3, and the breakthrough capacity was more than 505.4 μg for 300 mg KMnO4-MnO2 solid multisorbent, the average recovery rate was 96.4%~103.8%, the intra-day and inter-day precision was 3.0%~3.3% and 3.5%~5.2% respectively, the limit of detection was 0.0013 mg·m-3 (7.5 L of air ) and 0.000 6 mg·m-3(96 L of air), after sampling, and the solid multisorbent tube could be kept at least 30 d at room temperature without significant loss. The present method was simple and suitable for capturing mercury and its compounds in the workplace air and ambient air. The solid multisorbent tube was useful for personal sampling and time weighted average sampling..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1412 (2014)
X-Ray Diffraction and Infrared Spectrum Analysis of Fault Gouge in Wenchuan Seismic Belt
WANG Zheng-yang, CAO Jian-jin, LUO Song-ying, and LIAO Yi-peng
Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, Wenchuan earthquake produced a series of co-seismic surface ruptures in Leigu and Zhaojiagou, and we collected samples of co-seismic fault gouge in the surface ruptures as well as the old gouge in the fault of Nanba. Testing The new and old fault gouge was tested with X-ray diffraction and infrared absorption spectra, and its characteristics such as mineral compositions, clay mineral contents and combinations were comprehensively analyzed. The results display obvious differences between the new and old fault gouge, showing that the old fault gouge is mainly composed of wall rock debris or milled powders, while the main components of new fault gouge are clay minerals. The assemblage of clay minerals composition shows that the environment of the fault activity was mainly warm and humid, and the clay minerals were mainly transformed by low temperature and low pressure dynamic metamorphism. And this also partly indicates that the latest way of the fault activity in this area may be a creeping. However the previous researches on the fault gouge of Wenchuan earthquake fault zone are mainly focused on its mechanical properties as well as its texture and structure, the research in this paper is to determine the physical and chemical environment of fault activity through the mineral compositions and clay mineral contents in the fault gouge characteristics, and this research has important scientific significance to the researches on the evolution of the fault environment and the activity mechanism of the earthquake..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1416 (2014)
A Late-Type Star Spectra Outlier Data Mining System
CAI Jiang-hui, YANG Hai-feng, ZHAO Xu-jun, and ZHANG Ji-fu
In M star population, some special objects, which may be of magnetic activity, may be giant stars, or may be of other rare properties, are very important for the follow-up observation and the scientific research on galactic structure and evolution. For local bias of M-type star spectral characteristic lines contained iIn M star population, some special objects, which may be of magnetic activity, may be giant stars, or may be of other rare properties, are very important for the follow-up observation and the scientific research on galactic structure and evolution. For local bias of M-type star spectral characteristic lines contained in subspace, a late-type star spectra outlier data mining system is given in the present paper. Firstly, for the sample of M stellar spectral characteristic lines indices, its distribution characteristics in attribute spaces are measured by using the sparse factor and sparsity coefficient, and then this sample is discretized and dimension-reduced to the spectral subspace. Secondly, local outlier subspaces are extracted by PSO (particle swarm optimization) algorithm and identified. Additionally, the effects of sparse coefficient and sparse factor on the number of outliers are discussed by experiments on the sample of SDSS M stellar spectral line index set, and the outliers are compared with spectral type provided by SDSS. In this way, the feasibility and value of this system were validated..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1421 (2014)
A New Method of Anti-Jamming Ability Improvement for Michelson Interferometer
LI Yang-jun, LIAN Su-jie, SHI Jia, GUO Ya-fei, and WANG Gao
In order to improve anti-jamming capability of Michelson interferometer system, replace the traditional structure of the moving mirror scanning was replaced, an interference system based on electro-optic modulation of crystal refractive index was designed to achieve optical path scanning. The system modulated voltage sIn order to improve anti-jamming capability of Michelson interferometer system, replace the traditional structure of the moving mirror scanning was replaced, an interference system based on electro-optic modulation of crystal refractive index was designed to achieve optical path scanning. The system modulated voltage signal on the variable refractive crystal, to generate cyclical changes, changed the refractive index to control optical path difference in the original optical path system. Using electronic scanning to replace of mechanical scanning, improved the system’s noise immunity was improved. In the electro-optic modulation process, computed the maximum optical path difference of the system was computed, and analyzed of the crystal thickness and crystal diffraction efficiency of the modulation process were analyzed. The simulation experiment shows that, with the modulation voltage range increasing, the available range of the optical path is also increased, and the system spectrum resolving power will also increase accordingly. Meanwhile, in the modulation process set the modulation range was set to make the energy of diffraction energy losses less than 10% of the total energy, so as to ensure a better signal to noise ratio. Experimental results show that, as the modulation voltage changes, interference fringes occurred continuously moved. When the voltage is further increased, the nonlinear error appears. After non-linear error correction for the system, spectrum resolution reached to 7.2 cm-1, slightly lower than the original system. But its anti-jamming capability is greatly enhanced, as in the absence of experimental platform for seismic conditions, conventional interferometer relative error is more than 20%, while the relative error of the system is less than 5%, in line with the design requirements. It was proved that the anti-jamming capability of the system was enhanced greatly, when the static electro-optical modulation was used..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1425 (2014)
Calibration Transfer without Standards for Spectral Analysis Based on Stability Competitive Adaptive Reweighted Sampling
ZHANG Xiao-yu, LI Qing-bo, and ZHANG Guang-jun
A novel calibration transfer method based on stability competitive adaptive reweighted sampling (SCARS) was proposed in the present paper. An informative criterion, i.e. the stability index, defined as the absolute value of regression coefficient divided by its standard deviation was used. And the root mean squared errA novel calibration transfer method based on stability competitive adaptive reweighted sampling (SCARS) was proposed in the present paper. An informative criterion, i.e. the stability index, defined as the absolute value of regression coefficient divided by its standard deviation was used. And the root mean squared error of prediction (RMSEP) after transfer was also used. The wavelength variables which were important and insensitive to influence of measurement parameters were selected. And then the differences in responses of different instruments or measurement conditions for a specific sample were eliminated or reduced to improve the calibration transfer results. Moreover, in the proposed method, the spectral variables were compressed, making calibration transfer more stable. The application of the proposed method to calibration transfer of NIR analysis was evaluated by analyzing the corn with different NIR spectrometers. The results showed that this method can well correct the difference between instruments and improve the analytical accuracy. The transfer results obtained by the proposed method, orthogonal signal correction (OSC), Monte Carlo uninformative variable elimination (MCUVE) and competitive adaptive reweighted sampling (CARS), respectively, for corn with different NIR spectrometers indicated that the former gave the best analytical accuracy, and was effective for the spectroscopic data compression which can simplify and optimize the transfer process..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1429 (2014)
Study and Analysis of Light Infrared Detection System with Dual Spectrum and Wide Temperature Range
SHEN Man-de, JIANG Qing-xiu, REN Huan-huan, and LI Cheng
Because harmonic diffractive optics elements has special achromatism, athermalization and arbitrary phase modulation characteristics, an infrared detection system method with dual spectrum and wide temperature range was presented based on the most advanced infrared dual color detector which had a format of 320×240Because harmonic diffractive optics elements has special achromatism, athermalization and arbitrary phase modulation characteristics, an infrared detection system method with dual spectrum and wide temperature range was presented based on the most advanced infrared dual color detector which had a format of 320×240 and the pixel pitch of 30 μm. A hybrid refractive/harmonic diffractive infrared detection system with dual spectrum and wide temperature range was designed. The working wavelength range was 3.8～4.2 and 8.8～11.2 μm. The system was only consisted of three lenses, including one aspheric surfaces and a harmonic diffraction surface, which made the system have compact structure and light weight. In the temperature range -120～200 ℃, the RMS radius of spot diagram in 3.8～4.2 and 8.8～11.2 μm was 19.07 and 17.75 μm respectively, which is less than the pixel size of infrared detector with 30 m, the enclosed energy in 30 μm, the enclosed energy in 3.8～4.2 and 8.8～11.2 μm is 88.7% and 82.4% in two pixel size. The method and structure was convenient and predominant. It was proved that the design was feasible..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1434 (2014)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 5, 1 (2014)
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