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2005 Vol. 25, No. 12
Published: 2005-12-26
 
       光谱学与光谱分析
1905 Influence Factors Analysis for Laser-Induced Plasma Spectroscopy Measurements
LI Jing1, LIN Chang-he1, LI Sheng-li2
An experimental equipment has been set up for laser-induced plasma spectroscopic(LIPS) measurement based on a Nd:YAG Q-switched solid laser(average single pulse energy is 38 mJ) as exciting light source and the copper alloy as sample. The instrument time distribution of Cu radiation was obtained, and the software and hardware influence factors on the measured spectra were analyzed. The experiments proved that the fluctuation of laser output energy, average number of each datum, the position between the target surface and the lens focus, the position between the optical fiber bundle for receiving the radiation and the normal of the target surface, and the effective receiving area of the optical fiber bundle all influence the intensity of spectra and the reproducibility of measurement.
2005 Vol. 25 (12): 1905-1907 [Abstract] ( 1669 ) PDF (503 KB)  ( 443 )
1908 The Study of CO2 Cavity Enhanced Absorption and Highly Sensitive Absorption Spectroscopy
PEI Shi-xin,GAO Xiao-ming,CUI Fen-ping,HUANG Wei,SHAO Jie,FAN Hong,ZHANG Wei-jun*
Cavity enhanced absorption spectroscopy (CEAS) is a new spectral technology that is based on the cavity ring down absorption spectroscopy. In the present paper, a DFB encapsulation narrow line width tunable diode laser (TDL) was used as the light source. At the center output, the TDL radiation wavelength was 1.573 μm, and an optical cavity, which consisted of two high reflectivity mirrors (near 1.573 μm, the mirror reflectivity was about 0.994%), was used as a sample cell. A wavemeter was used to record the accurate frequency of the laser radiation. In the experiment, the method of scanning the optical cavity to change the cavity mode was used, when the laser frequency was coincident with one of the cavity mode; the laser radiation was coupled into the optical cavity and the detector could receive the light signals that escaped the optical cavity. As a result, the absorption spectrum of carbon dioxide weak absorption at low pressure was obtained with an absorption intensity of 1.816×10-23 cm-1·(molecule·cm-2)-1 in a sample cell with a length of only 33.5 cm. An absorption sensitivity of about 3.62×10-7 cm-1 has been achieved. The experiment result indicated that the cavity enhanced absorption spectroscopy has the advantage of high sensivity, simple experimental setup, and easy operation.
2005 Vol. 25 (12): 1908-1911 [Abstract] ( 184 ) PDF (544 KB)  ( 400 )
1912 Spectroscopic Analysis of Er3+ in Er3+/Yb3+ Co-Doped LiNbO3 Crystal
WANG Dun-chun, ZHANG De-long, CUI Yu-ming, CHEN Cai-he
At room temperature, α-polarized absorption spectra of as-grown and annealed Er3+/Yb3+ co-doped, Z-cut LiNbO3 single crystals, grown by using Czochralski method, were measured in the wavelength range of 300-1 650 nm. The spectroscopic properties of Er3+ were analysed by using Judd-Ofelt theory. The experimental values of the electron transition strengths of several major transitions from the ground state to excited-state manifolds were evaluated from the measured integrated absorption coefficients of Er3+. The Judd-Ofelt parameters were determined by using least square method. According to the fitted Judd-Ofelt parameters, the spontaneous emission rates, the fluorescence branch ratios from the excited-state manifolds J to the lower-lying manifolds J′, as well as the radiative lifetimes of the excited states were numerically calculated. In addition, Yb3+ co-doping and thermal anneal effects on the spectroscopic properties of Er3+ were also considered in this work.
2005 Vol. 25 (12): 1912-1915 [Abstract] ( 262 ) PDF (379 KB)  ( 404 )
1916 Determination of Reaction Products of Epoxypropane in the Process of Deflagration to Detonation Transition by Emission Spectroscopy
LI Ping1, 2, HU Dong2, 3, YUAN Chang-ying2, 4, XIAO Hai-bo1, LIU Jun-chao2, SUN Zhu-mei2, 3, DONG Shi2, 3
After solving problems of the synchronization of the measuring system, the detection of weak light, and the avoidance of false trigger signal, the instantaneous emission spectra of epoxypropane in the process of deflagration to detonation transition (DDT) with the exposure time of 1-16 μs and the resolution of 0.2 nm were measured. The spectra were acquired from side windows of an explosion shock tube 0.1 m in inner diameter and 4.0 m in length. The measuring system is made up of an intensified spectroscopic detector ICCD, a SpectraPro-275 spectrograph, and a digital delay generator DG535. By analyzing the spectra obtained, the reaction products OH, CH, C2, C3, CO, CO2, CHO and CH2O were identified according to their characteristic electronic and vibrational bands, which indicates that these molecules and radicals were produced during the DDT process of epoxypropane. The determination of reaction products can provide experimental basis for analyzing and understanding the microscopic mechanism of DDT process.
2005 Vol. 25 (12): 1916-1919 [Abstract] ( 376 ) PDF (549 KB)  ( 407 )
1920 Preparation and Room Temperature Emission of Nanocrystalline ZnO:Er3+
Lü Shu-chen1, 2，SONG Hong-wei2, HUANG Shi-hua2
The nanocrystalline ZnO:RE powders with room temperature sharp photoluminescence were prepared successfully by chemical precipitation method in the present work. This is a great progress in the study of rare earth doped ZnO. For the ZnO:Er3+ obtained in the present paper, the room temperature sharp characteristic emissions from the trivalent rare earth Er3+, including upconversion and near infrared emission, and the energy transfer between the nanocrystalline ZnO host and the dopants were observed.
2005 Vol. 25 (12): 1920-1924 [Abstract] ( 1651 ) PDF (575 KB)  ( 412 )
1925 Study on Two-Photon Induced Fluorescence of Newly Synthesized Chromophore BECVN and BMABN
SHI Qin-fen1, WANG Xiao-mei1*, JIANG Wan-li3, YANG Ping2, JIANG Xue-zhang1, WEN Di-jiang1,XU Gui-bao３
One-photon fluorescence(OPF) and two-photon fluorescence (TPF) of two chromophores 1,4-bis(9-ethyl-vinyl carbazole) naphthalene (abbreviated as BECVN) and 1,4-bis(4-N, N-methylamino styryl) naphthalene (abbreviated as BMABN) were resported. Strong emission at 492-541 nm and at 500-556 nm, respectively, were obtained under the excitation of ～370 nm (Xe lamp) and of 730-800 nm femto-second laser pulses, respectively. Although the relative fluorescence quantum yield (Φf) of BECVN is as high as 7.4 times that of BMABN, the latter possesses higher TPF intensity and larger two-photon absorption (TPA) cross-section, suggesting that BMABN containing naphthalene as π-center end-capped with N,N-methylamino styryl group exhibits more effective two-photon process. Lippert equation showed that the difference of dipole momnet (Δμge) between the ground state and the excited state for BECVN is nearly twice that for BMABN, conforming to that the Δμge value is not the key for the enhancement of two-photon absorption cross-section.
2005 Vol. 25 (12): 1925-1928 [Abstract] ( 454 ) PDF (512 KB)  ( 407 )
1929 Synthesis and Luminous Characteristics of Y(P,V)O4:Eu3+ Phosphors for PDP
LAI Hua-sheng1, 2, 3, CHEN Bao-jiu1*, XU Wu1, 4, XIE Yi-hua1, WANG Xiao-jun1, DI Wei-hua1, ZHAO Xiao-xia1
Y(P,V)O4:Eu3+ phosphors with good morphology for plasma display panels have been prepared via coprecipitation reaction. The phosphor was characterized by SEM and photoluminescence under UV(325 nm)and VUV(147 nm) excitation. The emission spectra depending on temperature under 325 nm excitation by laser indicated that there exist energy transfer between VO3-4 group and Eu3+ ion. Under 147 nm excitation, the most intense emission peaks of commercial (Y,Gd)BO3:Eu3+ phosphor range around 593 nm, and those of Y(P,V)O4:Eu3+phosphors prepared by coprecipitation reaction ranged around 619 nm. The red emission color purity of Y(P,V)O4:Eu3+ phosphor is much better than that of (Y,Gd)BO3:Eu3+, and its relative emission intensity is almost close to that of the commercial phosphor.
2005 Vol. 25 (12): 1929-1932 [Abstract] ( 1106 ) PDF (800 KB)  ( 366 )
1933 Donor Concentration Dependence of Upconversion Luminescence in YLiF4:Er3+, Yb3+
ZHAO Su-ling1, XU Zheng1，2, PEI Xiao-jiang1
YLiF4:Er3+, Yb3+ was synthesized by hydrothermal method. The concentration of Er3+ was 2 mol%, and Yb3+ changed from 0 to 7 mol%. At room temperature the absorbance of YLiF4:Er3+, Yb3+ in all samples was measured from 200 to 1 200 nm. The absorbance around 980 nm increased with increasing Yb3+ concentration. The result shows that the upconversion intensity excited at 980 nm was enhanced. The enhanced intensity is dependent on the Yb3+ concentration. The excitation spectra and photoluminescence spectra were measured in the sample with Yb3+ concentration of 2 mol%. The red and green luminescence came from the transition 4F9/2→2I15/2 , and 4S3/2→2I15/2 and 2H11/2→2I15/2 , respectively.
2005 Vol. 25 (12): 1933-1937 [Abstract] ( 1184 ) PDF (618 KB)  ( 383 )
1938 Determination of Norfloxacin by Flow-Injection Chemiluminescence
LIAO Su-lan1, 2, XIE Zeng-hong1*
Sodium dodecylsulfate(SDS) can greatly enhance the emission intensity of the weak chemiluminescence reaction of Ce(Ⅳ) with norfloxacin(NFLX) in acid medium. Based on this phenomenon, a simple and rapid new method for the continuous determination of norfloxacin was developed. The calibration graph is linear for 7.78×10-8-5.82×10-6 g·mL-1, the detection limit(3σ) is 1.57×10-8 g·mL-1, and the relative standard deviation (n=10, c=1.94×10-6 g·mL-1) is 1.7%. The method was successfully applied to the determination of norfloxacin in capsules. Additionally, the system’s mechanism was discussed.
2005 Vol. 25 (12): 1938-1942 [Abstract] ( 1529 ) PDF (536 KB)  ( 393 )
1943 Flow Injection Chemiluminescence Method for the Determination of Phenol with N-Bromosuccinimide-Luminol System
DU Ling-yun1, JI Ning-ning1, WANG Shu-hao1, 2*, ZHUANG Hui-sheng2
A novel flow injection chemiluminescence method was presented for the determination of phenol. The method is based on the quenching effect of phenols on the chemiluminescence reaction between luminol and N-bromosuccinimide. The linear range for the determination of phenol is 1.0×10-5-9.0×10-4 mg·mL-1, and the detection limit is 1.81×10-7 mg·mL-1. This method was used for the determination of phenol in water samples with satisfactory results. The mechanism of the reaction was also expounded.
2005 Vol. 25 (12): 1943-1946 [Abstract] ( 1548 ) PDF (371 KB)  ( 426 )
1947 Preparation and Spectral Characteristic of TiO2/SnO2 Composite Oxides
LIU Cheng-lin1, ZHONG Ju-hua2, LI Yuan-guang2, ZHANG Zhao-kui2
To study the spectral characteristic of TiO2/SnO2, TiO2/SnO2 composite oxide with SnO2 inside kernel was fabricated by colloid chemistry method, and was studied with UV-visible absorption spectrum, X-ray diffraction and infrared spectrum. The results showed that the bandgap widths of TiO2 and TiO2/SnO2 were 4.13 and 3.86 eV, respectively. TiO2/SnO2 had a widest and strong absorption band in the ultraviolet range. There was a quantum effect. In the X-ray diffraction, the station of TiO2 (110) diffraction peak moved 1.6°, and its intensity changed. Compared with TiO2 infrared spectrum, the Ti—O stretching vibration of TiO2/SnO2 moved from 500 to 656 cm-1, and had 560 cm-1 shoulder peak. The intensity of the peaks near 1 650 and 3 420 cm-1 corresponding to water absorbing peaks increased.
2005 Vol. 25 (12): 1947-1949 [Abstract] ( 1616 ) PDF (331 KB)  ( 372 )
1950 Application of O-PLS in Fundamental Study of Non-Invasive Measurement of Human Blood Glucose Concentration with Near Infrared Spectroscopy
Lü Li-na, LIU Rong, ZHOU Ding-wen*
Near-infrared diffuse reflectance spectroscopy is a promising approach to the non-invasive prediction of blood glucose levels. However, because the measured object is human body whose physiological structures are so complicated that it is very difficult to separate the information of glucose from the overlapped spectra using the traditional modeling method. A new regression method called orthogonal projections to latent structures (O-PLS), which integrated the orthogonal signal correction (OSC) preprocessing into the regular PLS modeling, was applied to the optimization and interpretation of the glucose near-infrared spectroscopy model. Applying O-PLS resulted in removal of non-correlated variation in spectra and reduced model complexity with preserved prediction ability, improved interpretative ability of variation in spectra.
2005 Vol. 25 (12): 1950-1954 [Abstract] ( 1023 ) PDF (568 KB)  ( 393 )
1955 Nodular Goiter Surface Detection by FTIR Spectroscopy
LING Xiao-feng1, XU Zhi1, XU Yi-zhuang2*, ZHOU Su1, ZHANG Neng-wei3, WANG Li-xin1, HOU Chun-sheng1, ZHANG Yuan-fu2, ZHOU Xiao-si1, WU Jin-guang2
A novel non-invasive diagnosis method of nodular goiter is proposed in the present study by recording FTIR spectra on the skin overlying thyroids using fiber optical technique and attenuated total reflection probe. FTIR spectra from 20 nodular goiters and 34 normal controls were collected. Twenty seven spectral variables of 13 bands including peak position and relative intensities were extracted from the FTIR spectra so that statistic work could be conducted using SPSS. The results demonstrate that peak positions of 2 925 and 1 250 cm-1 both shifted toward lower wave number(P＜0.05) in the FTIR spectra of nodular goiter. The relative intensity ratios of H1 740/H1 460, H1 160/H1 460, and H1 160/H1 120 decreased significantly in FTIR spectra of nodular goiter (P＜0.05). Inversely, H1 080/H1 460 increased significantly (P＜0.05) in nodular goiter. The above statistic differences suggest that nodular goiter may produce some characteristic chemical substance which can diffuse onto the surface of skin and therefore be detectable using FTIR spectroscopy with fiber optic techniques. These differences are the basis of diagnosing nodular goiter by FTIR surface detection.
2005 Vol. 25 (12): 1955-1958 [Abstract] ( 1098 ) PDF (483 KB)  ( 388 )
1959 An Applied Study on Fourier Transform Near-Infrared Whole Spectroscopy Regression Analysis
ZHANG Lu-da1,WANG Tao1, YANG Li-ming1, ZHAO Li-li2, ZHAO Long-lian2, LI Jun-hui2, YAN Yan-lu2
In the present paper, 66 wheat samples were used as experimental materials, 33 of them were used for building the quantitative analysis model of protein content, and the rest composed the prediction set. Using Moore-Penrose matrix, we estimated directly the regression coefficients of the regression analysis model with Fourier transform near-infrared(FTNIR)whole spectroscopy. The samples of prediction set were analyzed, and the correlation coefficient is 0.979 9 between the prediction values of the near-infrared model and the standard chemical ones by Kjeldahl’s method, and the average relative error is 1.76%. Using Moore-Penrose matrix, we can not only get the near-infrared spectroscopy analysis model’s regression coefficients, but also know their contribution at every wavelength point. Consequently we can understand and explain the physical and chemical significance of the FTNIR whole spectroscopy regression model.
2005 Vol. 25 (12): 1959-1962 [Abstract] ( 181 ) PDF (370 KB)  ( 399 )
1963 Study on the Robust NIR Calibration Models for Moisture
LI Yong1, WEI Yi-min1*, ZHANG Bo1, YAN Yan-lu2
The differences in sample moisture affect the robustness of NIR model obviously. In the present paper, three approaches, including preprocessing spectra, selecting wavelength, and setting up global calibration, were investigated to analyze the feasibility of setting up robust calibrations based on the protein content of wheat with different moistures. It has been found that with only spectral pretreatment method it fails to obtain satisfactory results, which can not remove the effects caused by moisture difference. Both selecting wavelengths and developing global calibration model proved to be good approaches for developing robust NIR calibration, yet developing global calibration is better. The mechanisms of the three different methods were also analyzed theoretically.
2005 Vol. 25 (12): 1963-1967 [Abstract] ( 983 ) PDF (641 KB)  ( 378 )
1968 Study on Microwave-Templated Synthesis Mechanism of LiMn2O4 by Infrared Spectroscopy
YANG Shu-ting1, 2, DONG Hong-yu1, 2, ZHAO Na-hong1, 2
In this paper, LiMn2O4 was synthesized by the microwave-template method, and the synthesis mechanism was studied by the in-situ FTIR. It was confirmed by the FTIR that polyacrylamide was decomposed gradually during the spinel LiMn2O4 preparation, and there was some chemical bond between the reactants and polyacrylamide in the precursors. Polyacrylamide acted as template in the course of the preparation of precursors and forming of spinel lithium manganese oxide compound. As a result of the certain chmical bond, the controlling and adjusting of the LiMn2O4 crystalline were realized, so that agglomeration and lacunae framework of the spinel was adjusted.
2005 Vol. 25 (12): 1968-1971 [Abstract] ( 1082 ) PDF (602 KB)  ( 415 )
1972 Quality Analysis of Powdered Milk via FTIR Spectroscopy
DENG Yue-e1, 2, ZHOU Qun2, SUN Su-qin2*
Eleven kinds of powdered milk were identified by Fourier transform infrared spectroscopy (FTIR). The main nutritious components had distinct fingerprint characteristics in the IR spectra of milk powder. For samples from the same factory but of different brands, there was some dissimilarities in the relative intensities of infrared absorption peaks due to the difference in fat, protein and carbohydrate as well. For the samples of the same sort, but from different factories, there were certain similarities in the IR spectra. The spectra of milk powders with high level of fat, protein, and carbohydrates have their own characteristic absorption prak in the FTIR. Three kinds of commonly used excipients: maltodextrin, sucrose and lactose, all have specific fingerprint features, which change as their amounts alter. The present research provides a fast and direct method for evaluating the quality of powdered milk.
2005 Vol. 25 (12): 1972-1974 [Abstract] ( 1162 ) PDF (418 KB)  ( 451 )
1975 Application of Cross-Correlation Analysis to Model Transfer of Near Infrared Spectrum
WU Zhong-chen1, XU Xiao-xuan1, YANG Ren-jie1, YU Gang2, ZHANG Cun-zhou1
Model transfer was studied by cross-correlation in near infrared spectrum. The hypothesis is that there exists an inherent proportional constant between the two spectra for model building measured by two different spectrometers after cross-correlation analysis is put forward and approved. The compatibility of the two models is enhanced after using the proportional constant. So the good results were obtained.
2005 Vol. 25 (12): 1975-1977 [Abstract] ( 1030 ) PDF (348 KB)  ( 420 )
1978 The Application of Correlation Detection to Near-Infrared Spectroscopy
LIU Qing-ge, SHAO Ding-rong, LI Shu-jian
Correlation detection was applied to near-infrared spectroscopy (NIRS) to extract the signal feature in the present paper. With metronidazole tablets as the object, the correlation both between each pure components and between pure metronidazole and different component-content mixtures were obtained. The results show that through correlation processing, the information feature of spectra could be separated and strengthened, and so better fitted to realize qualitative and quantitative spectrochemical analysis. Besides, the impact of noise could be lowered in this process. The conclusion is that correlation detection is an effective way to extract feature information and can be considered as a new solution to the problems of spectral superposition and low information rate in NIRS.
2005 Vol. 25 (12): 1978-1981 [Abstract] ( 348 ) PDF (539 KB)  ( 368 )
1982 Spectra of Rare Earth Complexes RE(Et2dtc)3(phen)
ZHU Li, CHEN San-ping, YANG Xu-wu, JIAO Bao-juan, GAO Sheng-li*
The ternary solid complexes RE(Et2dtc)3(phen) (RE=La, Pr, Nd, Sm-Er) were synthesized with sodium diethyldithiocarbamate (NaEt2dtc·3H2O), 1,10-phenanthroline (o-phen·H2O) and hydrated lanthanide chlorides in absolute ethanol by improved reported method. IR results revealed that RE3+ coordinated with sulfur atoms of NaEt2dtc and nitrogen atoms of o-phen. As for UV spectrum of the complexes, energy transfer between o-phen and RE3+ was the primary process, and the main absorption peaks showed a slight red shift compared to that of o-phen; FS spectrum, as a comparison, showed that the complexes Sm(Et2dtc)3(phen) and Eu(Et2dtc)3(phen) have a higher efficiency of intermolecular energy transfer and a stronger fluorescence character.
2005 Vol. 25 (12): 1982-1985 [Abstract] ( 1041 ) PDF (470 KB)  ( 414 )
1986 Probing R6G Single Molecules by Surface-Enhanced Resonance Raman Scattering
ZHOU Zeng-hui1, 2, LIU Li1, XIAO Fan-rong1, 2, WANG Gui-ying1, XU Zhi-zhan1
R6G was incubated in three kinds of silver colloid with different low concentrations, and its surface-enhanced resonance Raman scattering (SERRS) was studied with a confocal microscopy system. Each sample exhibited different spectrum character. At the single-molecule level the SERRS-spectra were recorded in 10-13 mol·L-1 dye colloidal solution. Some spectral inhomogeneous behavior was recorded such as spectral diffusion, intensity fluctuation of vibrational lines and spectral polarization, and even on/off blinking and splitting of some lines within the spectrum of one molecule. Polarization of excitation light and background subtraction of signal have an important influence on the SERRS spectra detection of single-molecule, which was analyzed in the present paper.
2005 Vol. 25 (12): 1986-1990 [Abstract] ( 1653 ) PDF (776 KB)  ( 458 )
1991 Surface-Enhanced Raman Scattering Studies of C60 on Ag Electrodes in Nonaqueous Solution
GU Wei,SUN Yu-hua,GU Ren-ao*
The spectroscopic characteristics of C60 on Ag electrodes in nonaqueous solution were studied by surface-enhanced Raman scattering (SERS) technique. The potential-dependent SER spectra of the C60 cluster indicate that a difference (about 400 mV) between the oxidation potential and the reduction potential appears when the potential scans negatively and positively. It is explained by that changes of electromagnetic field on Ag influence the structure of C60 molecule greatly. According to the SER spectra of C60 adsorbed on Ag electrodes, it was found that the symmetry of C60 is reduced because of Jahn-Teller distortion, and this decrease causes the changes in its SER spectra.
2005 Vol. 25 (12): 1991-1994 [Abstract] ( 1642 ) PDF (568 KB)  ( 413 )
1995 A Novel Light-Emitting Diode-Induced Fluorescence Detector for Micro-Scale Flow Analysis System
YANG Bing-cheng,TAN Feng,GUAN Ya-feng*
A compact light-emitting diode-induced fluorescence detector based on collinear scheme is described. The detector was assembled by all-solid-state optical-electronic components and easily coupled with micro-scale flow analysis system by on-column detection mode. Fluorescein isothiocyanate (FITC) and FITC-labeled amino acids were used as test analytes to evaluate the detector performance by capillary electrophoresis and flow injection analysis techniques. The concentration limit of detection was 10-8 mol·L-1 for FITC-labeled phenylalanine at a signal-to-noise ratio (S/N) of 3 (on-column, 0.05 mm i.d.). The system exhibited a good linear response in the range of 1×10-7-2×10-5 mol·L-1 (r2 =0.999). The relative standard deviation (RSD) of 6 repetitive injections on peak heights is less than 3%.
2005 Vol. 25 (12): 1995-1997 [Abstract] ( 1068 ) PDF (380 KB)  ( 359 )
1998 Electrochemical Synthesis and Spectroscopic Characterization of Gold Nanoparticles
SHEN Li-ming, YAO Jian-lin, GU Ren-ao*
Two electrochemical methods were used to synthesize Au nanoparticles(AuNPs) with different shapes depending on the applied current. The dumbbell, spheroid and rod-like AuNPs were synthesized by increasing the current with a certain increment, while spheroid and dumbbell AuNPs were obtained by applying constant current. The AuNPs were characterized by TEM, UV-Vis spectrum and surface enhanced Raman spectra (SERS). One absorption band located at near-IR region was observed on the AuNPs, indicating the existence of gold nanorods with the aspect ratio of about 6. The SERS effect from the AuNPs surface was studied by using crystal violet as probe molecules, which adsorbed on AuNPs surface with flat orientation. Meanwhile, the forming mechanism of AuNPs involving crystallization and growth was deduced based on the TEM results.
2005 Vol. 25 (12): 1998-2001 [Abstract] ( 588 ) PDF (708 KB)  ( 443 )
2002 Study of Raman Scattering of Plastic Optical Fiber
SUN Xiu-ping,FENG Ke-cheng,ZHANG Xi-he,TAN Yong,ZHANG Feng-dong,WANG Zhao-min
The first order stimulated Raman scattering (SRS) spectrum of PMMA plastic optical fiber was given, and the characteristic of the first order Stokes spectrum was studied. The threshold and the spectrum width were measured. The formation mechanism of SRS was analyzed, and then the first order Stokes spectrum of plastic optical fiber and that of silica fiber were compared.
2005 Vol. 25 (12): 2002-2004 [Abstract] ( 421 ) PDF (377 KB)  ( 408 )
2005 Vibrational Spectra of Thymine Calculated from DFT and Their Comparison with Experimental Results
SHANG Zhi-guo, BAI Ying, ZHANG Yan-ke, MO Yu-jun*
The vibrational spectra of thymine were predicted by density functional theory (DFT). In the calculation B3LYP complex function, and diffuse function and polarization function were added to heavy atoms and light atoms. Taking the effects of H-bonds into consideration, the authors added two water molecules in our calculation and simulated the case of forming H-bonds in crystal thymine. Whilst the Raman and infrared spectra of thymine were recorded, and the spectra of thymine calculated from DFT agree with the experimental results. The calculation results in the present paper are more approximate to the experimental data than ever reported. The vibrational modes of thymine were assigned.
2005 Vol. 25 (12): 2005-2008 [Abstract] ( 1436 ) PDF (351 KB)  ( 434 )
2009 A Holographic Plate Silver Film-Preparation, Morphology and SERS Activity
HUANG Yun-xia1, FANG Jing-huai2, SUN Zhen-rong1, YANG Xiao-hua1*
A new method for preparing SERS-active substrate was reported. After being exposed, developed and fixed, the commercially available holographic plate can be used to generate attractive SERS-active silver surface. The obtained silver film was characterized by UV-Vis spectroscopy and scanning electron microscope (SEM) observation. The absorption spectrum locates at around 420 nm with a narrow half-width due to the surface plasmon resonance, which implies that there are silver particles on the prepared substrate with uniform sizes. And the silver particles distribute uniformly anywhere on the holographic plate with a diameter of about 100 nm by SEM observation. Furthermore, the measurements of the SERS spectrum of crystal violet indicate that such substrate has the features of satisfactory reproducibility, long term stability and high SERS activity. The prepared silver film keeps high SERS activity even if it was stored for several months in the air at room temperature.
2005 Vol. 25 (12): 2009-2011 [Abstract] ( 1125 ) PDF (494 KB)  ( 397 )
2012 Effects of Different Levels of Vitamin C on UV Radiation-Induced DNA Damage
ZHOU Dian-feng, KE Wei-zhong*, CHEN Nian-feng, JI Kang
The Raman spectra of DNA in different levels of vitamin C with 10 min ultraviolet radiation and 30 min ultraviolet radiation were reported. The intensity of ultraviolet radiation was 18.68 W·m-2. The experimental results proved that vitamin C can reduce DNA damage solely, but the effects are related to the concentration of vitamin C. When the concentration of vitamin C was lower than 0.35 mmol·L-1, DNA was protected better with the rising of vitamin C concentration during ultraviolet radiation. DNA was protected best when vitamin C was 0.35 mmol·L-1. When vitamin C concentration was higher than 0.35 mmol·L-1, vitamin C accelerated DNA damage with 10 min ultraviolet radiation. But DNA was also protected with 30 min ultraviolet radiation as vitamin C was 0.35-0.65 mmol·L-1. However, DNA was only protected slightly at high concentration of vitamin C.
2005 Vol. 25 (12): 2012-2015 [Abstract] ( 1115 ) PDF (442 KB)  ( 401 )
2016 Study on the Fluorescence Spectra of 7-Hydroxyquinoline in Dimethyl Sulfoxide Solution
GUO Yang-xue1, LI Xiang-ping1, LIU Gui-qin2, ZHENG Jia-jin1, LIU Jing-jiang3, ZHANG Gui-lan1*, TANG Guo-qing1, CHEN Wen-ju1
7-hydroxyquinoline (7-HQ) is a kind of organic molecule with excited-state proton transfer (ESPT) effect. 7-HQ in ethanol solution causes ESPT reaction under the excitation of ultraviolet light. The fluorescence spectrum of the sample exhibits two bands. In contrast, 7-HQ in dimethyl sulfoxide (DMS) solution does not cause ESPT reaction. The fluorescence spectrum of the sample exhibits a single band. But after the sample was irradiated with a strong UV light, its fluorescence spectrum also exhibits two bands. This phenomenon is reported for the first time in the present paper, and its cause is investigated through the study on the absorption spectra and fluorescence spectra of 7-HQ in ethanol, dimethyl sulfoxide and N,N-dimethyl formamide solution. The conclusion is that the change in the fluorescence spectrum of 7-HQ in DMS solution is due to the fact that 7-HQ causes ESPT reaction which results from the photodecomposition of DMS and the product of water after the solution was irradiated with strong UV light.
2005 Vol. 25 (12): 2016-2019 [Abstract] ( 1096 ) PDF (374 KB)  ( 411 )
2020 Effects of Ultrasound Induction on Genomic DNA of Housefly Larvae
AN Chun-ju1, LI Feng2, ZHANG Li-jin2, LI De-sen1, DU Rong-qian1*
The genomic DNA of housefly larvae was extracted after ultrasound induction, and the structure was analyzed by UV, fluorescence, IR and 1H NMR. The 3′-end of attacin gene was sequenced and compared by means of PCR. All the results indicated that ultrasound induction can destroy the second structure and the base stacking of genomic DNA of housefly larvae, which will result in mismatch repair during DNA duplication and finally change the sequence of DNA, but it has no significant effect on chemical groups and chemical band of genomic DNA.
2005 Vol. 25 (12): 2020-2023 [Abstract] ( 1126 ) PDF (595 KB)  ( 407 )
2024 Three-Dimensional Excitation Emission Matrix Fluorescence Spectroscopic Characterization of Dissolved Organic Matter
FU Ping-qing1, 2, LIU Cong-qiang1,WU Feng-chang1*
Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM) was applied to characterize the fluorescence properties of dissolved organic matter (DOM) in lakes, rivers, streams, and ground waters. The results showed that the 3DEEM of DOM in aquatic environments mainly have four fluorescence peaks: peak A and C was referred to as fulvic-like fluorescence, and peak B and D was referred to as protein-like fluorescence. Results of river water DOM typically showed strong fulvic-like fluorescence. Polluted river waters often showed strong protein-like fluorescence. Four peaks were also found in the 3DEEM of lake DOM, which can origin from terrestrial runoff or from sources within the lakes. In Lake Baihua, strong protein-like fluorescence was found owing to the pollution by municipal wastewaters. Groundwater DOM has relatively lower DOC concentrations at 0.56-0.85 mg·L-1 and is characterized by fulvic-like fluorescence only if it was polluted by municipal wastewaters, and then it has strong protein-like fluorescence. The authors demonstrate that for all DOM samples, fluorescence intensity at peak C and absorption at 254 nm both showed a strong correlation with DOC concentrations(r2＝0.82 and 0.95, respectively). Also a strong linear correlation between UV-fulvic-like fluorescence and visible fulvic-like fluorescence was found (r2＝0.96). The fulvic-like fluorescence at peak A and C varied in accordance to each other with the pH of the DOM samples, and the maximum fluorescence occurred at pH 10, while the maximum value of protein-like fluorescence (peak B) occurred at pH around 8.5.
2005 Vol. 25 (12): 2024-2028 [Abstract] ( 2265 ) PDF (613 KB)  ( 607 )
2029 Study of a Multivariate Statistical 5-ALA-Based Discrimination Method for Fluorescence Spectra of Colonic Tissue of SD Rats
XIA Dai-lin1, HE Ji-shan1, ZHANG Yang-de2, TANG Jing-tian1, ZHANG Bo2, WANG Shao-chuang2, HUANG Qiu-lin2
In order to diagnosis colon early cancer with laser-induced 5-ALA-PpⅨ fluorescence spectra, a multivariate statistical method to distinguish these fluorescence spectra acquired in vivo was developed. 343 spectra were collected from 8 normal SD rats, and 20 1,2-DMH-induced SD colon cancer models，and 12 second generation rats of induced rats. 150 min after trail intravenous injections of 5-ALA at a dose of 25 mg·kg-1 BW, fluorescence spectra excited with 370 nm Ti-laser were collected in vivo. All spectra were divided into a calibration group and a prediction group. After preprocessing, 4 principal components were extracted with PCA. And then, discrimination models were built by stepwise multivariate logistic regression (SMLR) on calibration group. 3 pathological styles were combined each other, and then 3 SMLR models were derived. Normal tissues were classified from early cancers and advanced cancers with sensitivity of 100% and 98.4%, and specificity of 96% and 100%, and accuracy of 98% and 99.2% on prediction group, respectively. The multivariate statistical discrimination method of PCA and SMLR together can effectively distinguish normal tissues from early cancers and advanced cancers with high sensitivity and specificity by means of systemic 5-ALA at low dose. laser induced fluorescence 5-ALA-based technique is promising for the detection of colonic early cancer.
2005 Vol. 25 (12): 2029-2033 [Abstract] ( 1589 ) PDF (682 KB)  ( 394 )
2034 Synthesis, Structure Characterization and, Fluorescence Studies of the Complexes of Europium with Phenylglyoxylic Acid, 1,10-Phenanthroline and Triphenyl Phosphine Oxide
ZHANG Yan-hui1,SUN Bo1*,YAN Xiao-qi1,PEI Juan1,GENG Xiao-tian1,ZHAO Ying2,WANG Yun-you3,YAN Jian-bo3
Three novel europium complexes, Eu-L, EuL3phen and EuL2(TPPO)2NO3, were synthesized (HL=phenylglyoxylic, phen=1,10-phenanthroline, and TPPO=triphenyl phosphine oxide). The complexes were characterized by elemental analysis, conductivity, IR, and 1H NMR. The IR spectra indicated that all the complexes havea a larger Δν(νas(CO-2)-νS(CO-2) than that of NaL, and carboxylate ions in the phenylglyoxyate coordinated as unidentate ligands. And α-aeto also coordinated with the europium ions. In 1H NMR, the signals of hydrogens in the phenylglyoxyate shifted toward upfield, and those in phen or TPPO slightly shifted.The excitation and emission spectra were recorded at room temperature, and the excitation spectra showed that the optimum excitation wavelengths were 374.0, 358.2 and 383.4 nm, Five emission bands of the complexes due to 5D0—7F0, 5D0—7F1, 5D0—7F2, 5D0—7F3 and 5D0—7F4 transitions were observed in the region of 550-720 nm (Eu-L: 577.8, 590.2, 614.0, 648.4 and 695.4 nm; EuL3phen: 578.0, 588.4, 591.6, 611.2, 617.0, 649.4, 687.6 and 698.6 nm; EuL2(TPPO)2NO3: 577.8, 590.4, 614.6, 649.2 and 697.6 nm). The emission intensities of europium ions were obviously sensitized by TPPO.
2005 Vol. 25 (12): 2034-2038 [Abstract] ( 239 ) PDF (497 KB)  ( 425 )
2039 Fluorescent Characters of Optical BOD Sensing Film
ZHAO Li1, XIAO Lai-long1, LIN Ling1, CHEN Xi1, 2*, WANG Xiao-ru1
We characterized an optical BOD sensing film used to immobilize three kinds of microorganisms from seawater. The sensing film for BOD measurement consists of an optical oxygen sensor and the microorganisms immobilized on poly(vinyl alcohol) ormosils matrix. The fluorescent responses of the BOD sensing film were obviously affected by the thickness of the oxygen film and the concentration of microorganisms in the film. Some other experimental conditions, such as pH, measurement temperature, and the concentration of sodium chloride, were studied. BOD values estimated by this optical BOD sensing film correlate well with those determined by the conventional BOD5 method for seawater samples.
2005 Vol. 25 (12): 2039-2043 [Abstract] ( 1613 ) PDF (818 KB)  ( 386 )
2044 Effect of Thermal Treatment of Nanotubed H2Ti2O4(OH)2 on Photoluminescence Properties
LI Qiu-ye, JIN Zhen-sheng*, ZHANG Shun-li, TIAN Bao-li, ZHANG Zhi-jun
The effect of thermal treatment (100 ℃，-0.1 MPa) of nanotubed H2Ti2O4(OH)2 on photoluminescence properties was investigated. The results showed that the photoluminescence intensity of dehydrated nanotubed H2Ti2O4(OH)2 increases with the treatment time(t) when t≤23 h, and decreases when t＞23 h, which is different from the changes in ESR intensity and absorption with t. It can be explained as follows：When the concentration of single-electron trapped oxygen vacancies(V·O) generated from dehydration reaches a threshold value, strong interaction will take place between the adjacent V·O. This will result in decreasing the probability of photoluminescence emission, and increasing the probability of nonradiative transition. So the photoluminescence intensity of dehydrated nanotubed H2Ti2O4(OH)2 is enhanced first, and then decreases.
2005 Vol. 25 (12): 2044-2047 [Abstract] ( 1645 ) PDF (445 KB)  ( 356 )
2048 Determination of Protein with TPPS by Total Internal Reflection Synchronous Fluorescence Spectroscopy
CHEN Ying, YAO Min-na, TANG Yao-ji, LI Yao-qun*
A new method of quantitative determination for serum albumin in aqueous solution has been developed by measuring total internal reflection synchronous fluorescence at the solid/liquid interface. The combination of bovine serum album in (BSA) and meso-tetrakis (4-sulphonatophenyl) porphyrin (TPPS) adsorbed onto the glass surface produced a synchronous fluorescence signal at 421 nm. At pH 4.25, the signal intensity of BSA adsorbed on the interface was proportional to the BSA concentration in bulk solution. The linear range of 1.0-8.0 μg·mL-1 and the detection limit of 0.94 μg·mL-1 were obtained. The human serum samples were determined with satisfactory results.
2005 Vol. 25 (12): 2048-2051 [Abstract] ( 1636 ) PDF (412 KB)  ( 438 )
2052 Studies on Ru(bipy)2dppx2+ as Interacting Mode Spectroscopic Probe of DNA
CHEN Fang1，2, HE Zhi-ke1*
The interacting mode of adriamycin with DNA has been studied by the use of molecular “light switch" complex Ru(bipy)2dppx2+ as a interacting mode spectroscopic probe. The results of the influence of ADM on the fluorescence and Scatchard equation of Ru(bipy)2dppx2+-DNA system indicate that ADM intercalates the base pairs of DNA. Compared with normal DNA interacting mode spectroscopic probe EB, Ru(bipy)2dppx2+ has the advantages of higher sensitivity, lower toxicity, higher stability and simplicity.
2005 Vol. 25 (12): 2052-2055 [Abstract] ( 992 ) PDF (429 KB)  ( 342 )
2056 Analysis and Application of Excitation Fluorescence Intensity of Blood
ZHAO Zhi-min1, GUO Lin-feng1, YU Xiao-lei1, MA Jun-yan2, WANG Le-xin1,XIN Yu-jun1
The analysis technique of fluorescence is adopted to study the intensity of excitation fluorescence of blood in the present paper. The theoretical analysis and differences of normal and abnormal blood (hyperglycemia，hyperlipemia) are presented. The theoretical analysis was proved by experiment results. It was discovered that blood sugar consistency has an effect on blood fluorescence. In other words，with the same excitation wavelength and with blood sugar consistency increasing，the fluorescence intensity increases gradually. It is obvious that blood sugar is also a kind of fluorescein，and its consistency has an effect on fluorescence intensity，which is identical with the theoretical analysis, indicating that the experiment is successful，and it is possible to distinguish blood sugar consistency by comparing the fluorescence intensity in blood. It was also discovered that the higher the cholesterin content, the more intense the fluorescence, When excitation wavelength is especially 435 nm，the phenomenon is very obvious. The study paves a new way for the blood quick check and diagnosis of diseases.
2005 Vol. 25 (12): 2056-2060 [Abstract] ( 388 ) PDF (868 KB)  ( 362 )
2061 Study on the Determination of Ciprofloxacin by the Terbium(Ⅲ) Ion Fluorescence Probe Sensitized by the Surfactant
TONG Chang-lun, XIANG Guang-hong, LIU Wei-ping
The experiments indicated that terbium(Ⅲ) ion could complex ciprofloxacin, then emitted the characteristic fluorescence of terbium(Ⅲ) ion. When the surfactant of SDBS was added, the fluorescence intensity of the system was greatly increased. From this, a sensitive method of determining the ciprofloxacin was developted. The fluorescence intensity was determined by a 1 cm quartz cell with the excitation wavelength of 300 nm and the emission wavelength of 545 nm. The optimal conditions are as follows: pH 8.0-8.5, the concentration of terbium(Ⅲ) is 5.0×10-5 mol·L-1, the surfactant concentration of SDBS is 8.0×10-4 mol·L-1. The linear range is 2.5×10-6 mol·L-1 -2.0×10-8 mol·L-1, and the detection limit (S／N＝3) is 4.0×10-9 mol·L-1. The presented method was applied to determine the real pharmaceuticals of ciprofloxacin.
2005 Vol. 25 (12): 2061-2064 [Abstract] ( 1685 ) PDF (420 KB)  ( 432 )
2065 Preparation of Fe3+-Doped TiO2 Nanometer Thin Film and Study on Its Photocatalytic Performances
ZHENG Huai-li1，2，ZHANG Jun-hua1, LI Hong2, LI Zhi-liang1
In the present paper，Fe3+-doped TiO2 nanometer thin films were prepared on the surface of glass by sol-gel processing. Effects of ferro-dopant, PEG addition levels, and the number of layers on transmittance and photocatalytic degradability were then respectively investigated. Meanwhile some relative mechanisms of the effects were discussed. It was shown that the photocatalytic activity of the films could be promoted by ferro-dopant, and the rate of degradation was 1.38 times that without ferro-dopant. Moreover, the optimal photocatalytic activity and transmittance were obtained by adding 0.1g(0.13wt%) PEG to the sol precursor. In addition, the TiO2 nanometer thin films with 2 to 5 layers all had better transmittance, and the best one for practical application had two layers. The glass coated with TiO2 nanometer thin film shows potential and wide application value in construction industry, lamps manufacture, urban lighting engineering, etc. because of its remarkable abilities of self-purification, economy in energy, and environmental protection.
2005 Vol. 25 (12): 2065-2069 [Abstract] ( 1832 ) PDF (683 KB)  ( 387 )
2070 Spectrophotometric Simultaneous Determination of Pyrocatechol, Resorcinol and Hydroquinone by LM-BP Neural Network
KAI Xiao-ming1,SHEN Yu-hua2,ZHANG Gu-xin1,XIE An-jian2
By means of artificial neural network and Levenberg Marquardt Back Propagation(LM-BP) train algorithm，the three components of pyrocatechol, resorcinol and hydroquinone were determined simultaneously. The absorption spectra of these three components severely overlap in ultraviolet spectral range. Three wavelengths at 283.5, 279.5 and 276.5 nm were selected for the determination. 25 mixture standard solutions were prepared according to orthogonal projection form L25(56). Three kinds of components were trained. Mean Squared Error (MSE) reaching minimum value is 0.083 114 3. Meanwhile the contents of pyrocatechol, resorcinol and hydroquinone in six simulation mixture samples were predicted. The relative errors of the three kinds of components were slightly larger under the low concentration condition, and the mean relative error for most analytical results was less than 5%, especialmy it is satisfactory for the analytical results of pyrocatechol and resorcinol with severely overlapped absorption spectra.
2005 Vol. 25 (12): 2070-2072 [Abstract] ( 668 ) PDF (360 KB)  ( 424 )
2073 Determination of Mercury in Shark Liver by Cold Atom Fluorescence Spectrometry after Microwave Dissolution
WENG Di
The conditions for the determination of mercury in shark liver by cold atom fluorescence spectrometry (CAFS) with microwave dissolution were studied. After being dried completely，the method employed 2 mol·L-1 HNO3-4 mol·L-1 HCl as an oxidant，and with catalysis by V2O5, the samples were digested in a microwave oven. The mercury in absorption solution was reduced by SnCl2, and then was determined by CAFS at wavelength of 253.7 nm. 10% SnCl2 solution was used as a reductive agent for mercury. The linear range was 0-2.0 ng·mL-1 mercury (r=0.999 7). The detection limit was 0.05 ng·mL-1, the relative standard deviation was 0.86%-2.22%, and the average recovery rate was 96.0%-108.5%. The method was suitable for the determination of mercury in shark liver.
2005 Vol. 25 (12): 2073-2075 [Abstract] ( 1014 ) PDF (373 KB)  ( 370 )
2076 Determination of Polysaccharide from Chinese Medicine Morinda Officinalis How and Its Trace Elements Analysis
WU Yong-jun, LIU Jie, WU Yu-ming, LIU Li-e, ZHANG Hong-quan*
Polysaccharide was extracted from morinda officinalis how by back-flowing with 80% ethanol for 1 h, and the method of improved phenol-sulfuric acid spectroscopy was adopted to determine the content of morinda officinalis how polysaccharide. As for its trace elements, the atomic absorption spectroscopy was used to detect the content of Zn, Fe and Cu, which were compared with its fake; and cold atomic fluorometry was applied to determine the trace mercury. The results were satisfactory, which can give reference about the effective components of morinda officinalis how, and will help to exploit it.
2005 Vol. 25 (12): 2076-2078 [Abstract] ( 1035 ) PDF (489 KB)  ( 386 )
2079 Determination of Trace Elements in Edible Cactus by Atomic Absorption Spectrometry
LI Gui-hua,LIU Jun-shen,WANG Yu-bao,CHEN Yu-jing
The contents of 10 trace elements in edible cactus were determined by air-acetylene flame atomic absorption spectrometry. The sample was dissolved by ashing method. The experiment conditions were optimized by preparing mixed standard solution of these elements and adding LaCl3 and CsCl for interfering complements. The results show that the contents of following elements in the cactus are: 13-47 mg·g-1 for Mg，K and Ca;108-243 μg·g-1 for Zn，Mn，Fe and Na; 34.8 μg·g-1 for Cu，and 9.8-11.7 μg·g-1 for Ni, Sr;and the contents of Mg，K，Ca，Zn，Mn，Fe，Na and Cu are higher than those in carrot.
2005 Vol. 25 (12): 2079-2081 [Abstract] ( 1432 ) PDF (370 KB)  ( 347 )
2082 Speciation Analysis of Chromium(Ⅵ) and Chromium(Ⅲ) in Water Sample Using Flame Atomic Absorption Spectrometry with TOA-Benzene Extraction Separation System
Shawket Abliz1, WANG Ji-de1, Horshida2
A rapid and sensitive method for the sequential determination of Cr(Ⅵ) and Cr(Ⅲ) in water samples based on flame atomic absorption spectrometry with TOA-benzene extraction separation system has been developed. In the H2SO4 medium, Cr(Ⅵ) in sample solution was extracted into the organic phase by using the TOA-Benzene and Cr(Ⅲ) remained in the water phase. Cr(Ⅵ) in the organic phase and Cr(Ⅲ) in the water phase were determined separately by AAS. This method is simple, fast and of microscale. The results obtained by this method agreed well with those obtained by conventional method. The recoveries are 95.0%-102% for Cr(Ⅵ) and 94.8-103% for Cr(Ⅲ). The relative standard deviations were 2.9% for Cr(Ⅵ) and 2.6% for Cr(Ⅲ). The system has enrichment effect for Cr(Ⅵ), and the detection limits are 6.6 μg·L-1 for Cr(Ⅵ) and 0.20 mg·L-1 for Cr(Ⅲ). The maximum extracted amount of Cr(Ⅵ) by TOA was 4.6 mg·mL-1.
2005 Vol. 25 (12): 2082-2084 [Abstract] ( 1025 ) PDF (374 KB)  ( 327 )
2085 A Rapid Method for the Measurement of Major and Minor Elements in Vanadium Titanium Magnetite Sample
CHEN Yong-jun1, DENG Sai-wen1, DONG De-fan2, ZHENG Miao-zi1
A high resolution (203 eV/Mn Kα) portable X-ray fluorescence spectrometer has been developed and the measurement of major and minor elements in vanadium titanium magnetite sample was carried out. An 241Am radioactive source for X-ray excitation, a Si-PIN detector and a 2048 channel analyzer for the measurement of vanadium titanium magnetite direct powder sample were used. The correction methods for interferences, calibration and drift are presented. The method is simply, accurate and rapid. The detection limit is an order of magnitude lower compared with a sealed proportional counter system.
2005 Vol. 25 (12): 2085-2087 [Abstract] ( 1024 ) PDF (354 KB)  ( 483 )
2088 Non-Parameter Estimation Algorithm to Determine Stellar Effective Temperature
ZHANG Jian-nan1, 2,WU Fu-chao1,LUO A-li2,ZHAO Yong-heng2
The effective temperature of a star is one of the most important parameters, which determine the continuum and spectral lines in the stellar spectrum. A non-parameter estimation algorithm is proposed to estimate the stellar effective temperature in the present paper. Firstly, the spectrum data is processed by principal component analysis(PCA), then, an estimating model based on a Gaussian kernel function is set up using the PCA data and their temperatures. Experiments were carried out to verify the efficiency, and numerical robustness of the algorithm is also tested.
2005 Vol. 25 (12): 2088-2091 [Abstract] ( 1038 ) PDF (398 KB)  ( 486 )
2092 Application of Microwave Dielectric Spectrum to Analysis of Low-Carbon Alcohols in Water
WU Shou-guo1, ZHU Qiong-fen1, WANG Ju-shu2, WANG Hai-tian2, ZHENG Qing-he3, AN Yi-ting3
A novel technique for detecting low-carbon alcohols in water at microwave frequency is presented. The technique is based on the measurement of microwave scattering parameters of aqueous solutions containing alcohols. The method employs transmission-line technique at frequency field. The scattering parameters were obtained by measuring the microwave transmission power. The changes in scattering parameters were measured when a sample vessel filled with aqueous solution containing low-carbon alcohols was inserted in the microwave transmission line. It is shown, from the experimental data, that there are good linear relationships between the scattering parameters and the concentrations of alcohols within a certain range.
2005 Vol. 25 (12): 2092-2096 [Abstract] ( 1169 ) PDF (586 KB)  ( 385 )
2097 《光谱学与光谱分析》2005年(第25卷)总目次(第1～12期)
光谱学与光谱分析
2005 Vol. 25 (12): 2097-2110 [Abstract] ( 789 ) PDF (3513 KB)  ( 388 )

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