Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of va...Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of various spectroscopic techniques, mainly including atomic absorption spectrometry (AAS) inductively coupled plasma emission spectrometry (ICP-AES) X-ray fluorescence spectroscopy (XRF) atomic fluorescence spectroscopy (AFS) direct reading spectroscopy (OES) glow discharge emission spectroscopy (GD-OSE) laser-induced breakdown spectroscopy (LIBS), in the formulation of non-ferrous metal standards in China. The AAS method was the most widely used single-element microanalysis method among the non-ferrous metal standards. The ICP-AES method was good at significant advantages in the simultaneous detection of multiple elements. The XRF method was increasingly used in the determination of primary and secondary trace elements due to its simple sample preparation and high efficiency. The AFS was mostly detected by single-element trace analysis. OES GD-OES and LIBS were playing an increasingly important role in the new demand area for non-ferrous metals. This paper discussed matrix elimination, sample digestion, sample preparation, instrument categories and other aspects of some standards, and summarized the advantages of spectral analysis and traditional chemical analysis methods. The new methods of future spectroscopic technology had been illustrated in the process of developing non-ferrous metal standards.展开更多
Atmospheric pressure glow discharges were generated in an air gap between a needle cathode and a water anode. Through changing the ballast resistor and gas gap width between the electrodes, it has been found that the ...Atmospheric pressure glow discharges were generated in an air gap between a needle cathode and a water anode. Through changing the ballast resistor and gas gap width between the electrodes, it has been found that the discharges are in normal glow regime judged from the currentvoltage characteristics and visualization of the discharges. Results indicate that the diameter of the positive column increases with increasing discharge current or increasing gap width. Optical emission spectroscopy is used to calculate the electron temperature and vibrational temperature. Both the electron temperature and the vibrational temperature increases with increasing discharge current or increasing gap width. Spatially resolved measurements show that the maxima of electron temperature and vibrational temperature appeared in the vicinity of the needle cathode.展开更多
Optical emission spectroscopy was used to study a gas mixture glow discharge of CO2 and N2 at a total pressure of 1.2 Torr, a power of 100 W and a flow of 16.5 L/min. The emission bands were measured in the wavelength...Optical emission spectroscopy was used to study a gas mixture glow discharge of CO2 and N2 at a total pressure of 1.2 Torr, a power of 100 W and a flow of 16.5 L/min. The emission bands were measured in the wavelength range of 200 nm to 900 nm. The principal species observed were O2^＋ （A^2П→ X^2П）, CO^＋ （A^2П→X^2∑）, N2^＋ （B^2∑u＋ → X^2∑g^＋）, CO2^＋ （A^2∏ → X^2∏）, N2（C^3∏u → B^3∏g）, O2（b^1∑g^＋→ X^3∑g^-）, and CO （a^r3∑→a^3∏）. The behavior of the band intensities as a function of the N2 percentage is consistent with recent Monte Carlo simulations. The electron temperature and ion density were determined by a double Langmuir probe. The electron temperature was found in the range of 1.55 eV to 2.93 eV, and the electron concentration in the order of 10^10 cm^-3. The electron temperature and ion density at pure N2 and pure CO2 agree with previous measurements.展开更多
Optical emission spectroscopy in nitrogen glow discharge plasma is simulated, and the collision excitations and characteristic emissions of the species （N2, N2^＋, N^＋, N） are investigated by a Monte Carlo model fo...Optical emission spectroscopy in nitrogen glow discharge plasma is simulated, and the collision excitations and characteristic emissions of the species （N2, N2^＋, N^＋, N） are investigated by a Monte Carlo model for nitrogen molecular gas discharge. The excitation rates of the main excited states are calculated and the corresponding relation and relative magnitude between the distribution of excitation rate of a certain excited state and the distributions of the emission rates of various lines originating from this excited level are also explored. The simulated results are compared with the experimental measurements in two typical discharge conditions. The luminescence mechanism of the line N2^＋： 391.4 nm is explained based on the microscopic plasma processes. The cathode glow in N2 discharge is found to be mainly caused by N^＋ impact excitation and the intensity of cathode glow decreases with the voltage. The corresponding relation between the emission rate or intensity of the 391.4 nm line and the production rate and the density of N2^＋ is also examined.展开更多
Optical emission spectroscopy （OES） was applied for plasma characterization during the erosion of asphaltene substrates. An amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air-pla...Optical emission spectroscopy （OES） was applied for plasma characterization during the erosion of asphaltene substrates. An amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air-plasma glow discharge at a pressure of 1.0 Torr. The plasma was generated in a stainless steel discharge chamber by an ac generator at a frequency of 60 Hz, output power of 50 W and a gas flow rate of 1.8 L/min. The electron temperature and ion density were estimated to be 2.15±0.11 eV and （1.24±0.05）× 10^16 m^-3, respectively, using a double Langmuir probe. OES was employed to observe the emission from the asphaltene exposed to air plasma. Both molecular band emission from N2, N2＋, OH, CH, NH, O2 as well as CN, and atomic light emission from V and Hγ were observed and used to monitor the evolution of asphaltene erosion. The asphaltene erosion was analyzed with the aid of a scanning electron microscope （SEM） equipped with an energy dispersive X-ray （EDX） detector. The EDX analysis showed that the time evolution of elements C, O, S and V were similar and the chemical composition of the exposed asphaltenes remained constant. Particle size evolution was measured, showing a maximum size of 2307 μm after 60 min. This behavior is most likely related to particle agglomeration as a function of time.展开更多
电解液阴极大气压辉光放电-原子发射光谱ELCAD-AES是一种新兴的快速、高效、实时、在线的元素分析方法。将ELCAD-AES技术应用于水体中金属元素检测,选取K I 766.5 nm,Ca I 422.7 nm,Zn I 213.8 nm和Pb I 405.78nm为分析谱线,Hβ为内标谱...电解液阴极大气压辉光放电-原子发射光谱ELCAD-AES是一种新兴的快速、高效、实时、在线的元素分析方法。将ELCAD-AES技术应用于水体中金属元素检测,选取K I 766.5 nm,Ca I 422.7 nm,Zn I 213.8 nm和Pb I 405.78nm为分析谱线,Hβ为内标谱线,分别建立基本定标法和内标法的光谱分析定标曲线,对4种元素的检验样品进行测定。实验结果表明,K,Ca,Zn和Pb基本定标曲线拟合度R2分别为0.9951,0.9985,0.9917和0.9934,相对误差为1.1%和2.4%,1.2%和0.94%,8.3%和0.83%,4.0%和1.9%;采用内标法,4种元素定标曲线的拟合度分别达到0.996,0.9996,0.9994和0.9996,相对误差可达到0.25%和1.8%,0.44%和0.34%,2.6%和0.19%,2.4%和0.94%。说明内标法可提高定标曲线的拟合度,减少定量分析误差,提高测量精度。展开更多
Depth profiles of absorbed hydrogen introduced by electrochemical charging and light elements were analyzed in Ni-Nb-Zr-H amorphous alloy ribbons using a glow discharge optical emission spectrometer. It was clarified ...Depth profiles of absorbed hydrogen introduced by electrochemical charging and light elements were analyzed in Ni-Nb-Zr-H amorphous alloy ribbons using a glow discharge optical emission spectrometer. It was clarified that the absorbed hydrogen was comparatively well-distributed on the sample surface and that the content of the hydrogen decreased with increasing depth from the surface. That is, the amount of absorbed hydrogen on the surface was about 17 at %, while that inside the specimens decreased to several atomic percent. The depth profiles of the hydrogen which were close to the surface were slightly different between those on the roller side and those on the free side in the melt-spun ribbon. The difference is thought to originate from the existence of oxygen impurity on the surface and from the difference of the Zr content.展开更多
文摘Spectral analysis was a method of identifying substances, determining their chemical composition and calculating their content based on their spectral characteristics. This paper mainly discussed the application of various spectroscopic techniques, mainly including atomic absorption spectrometry (AAS) inductively coupled plasma emission spectrometry (ICP-AES) X-ray fluorescence spectroscopy (XRF) atomic fluorescence spectroscopy (AFS) direct reading spectroscopy (OES) glow discharge emission spectroscopy (GD-OSE) laser-induced breakdown spectroscopy (LIBS), in the formulation of non-ferrous metal standards in China. The AAS method was the most widely used single-element microanalysis method among the non-ferrous metal standards. The ICP-AES method was good at significant advantages in the simultaneous detection of multiple elements. The XRF method was increasingly used in the determination of primary and secondary trace elements due to its simple sample preparation and high efficiency. The AFS was mostly detected by single-element trace analysis. OES GD-OES and LIBS were playing an increasingly important role in the new demand area for non-ferrous metals. This paper discussed matrix elimination, sample digestion, sample preparation, instrument categories and other aspects of some standards, and summarized the advantages of spectral analysis and traditional chemical analysis methods. The new methods of future spectroscopic technology had been illustrated in the process of developing non-ferrous metal standards.
基金supported by National Natural Science Foundation of China(Nos.10805013 and 51077035)Funds for Distinguished Young Scientists of Hebei Province,China(No.A2012201045)+2 种基金the Key Project of Chinese Ministry of Education(No.210014)the Natural Science Foundation of Hebei Province(No.A2011201132)Hebei Province Department of Education for Outstanding Youth Project of China(Y2011120)
文摘Atmospheric pressure glow discharges were generated in an air gap between a needle cathode and a water anode. Through changing the ballast resistor and gas gap width between the electrodes, it has been found that the discharges are in normal glow regime judged from the currentvoltage characteristics and visualization of the discharges. Results indicate that the diameter of the positive column increases with increasing discharge current or increasing gap width. Optical emission spectroscopy is used to calculate the electron temperature and vibrational temperature. Both the electron temperature and the vibrational temperature increases with increasing discharge current or increasing gap width. Spatially resolved measurements show that the maxima of electron temperature and vibrational temperature appeared in the vicinity of the needle cathode.
基金supported by UAEM 2260/06, UAEM 2362/2006U, PROMEP FE018/2003 of Mexico
文摘Optical emission spectroscopy was used to study a gas mixture glow discharge of CO2 and N2 at a total pressure of 1.2 Torr, a power of 100 W and a flow of 16.5 L/min. The emission bands were measured in the wavelength range of 200 nm to 900 nm. The principal species observed were O2^＋ （A^2П→ X^2П）, CO^＋ （A^2П→X^2∑）, N2^＋ （B^2∑u＋ → X^2∑g^＋）, CO2^＋ （A^2∏ → X^2∏）, N2（C^3∏u → B^3∏g）, O2（b^1∑g^＋→ X^3∑g^-）, and CO （a^r3∑→a^3∏）. The behavior of the band intensities as a function of the N2 percentage is consistent with recent Monte Carlo simulations. The electron temperature and ion density were determined by a double Langmuir probe. The electron temperature was found in the range of 1.55 eV to 2.93 eV, and the electron concentration in the order of 10^10 cm^-3. The electron temperature and ion density at pure N2 and pure CO2 agree with previous measurements.
基金Natural Science Foundation of Hebei Province of China(Nos.A2006000123,F2006000183)
文摘Optical emission spectroscopy in nitrogen glow discharge plasma is simulated, and the collision excitations and characteristic emissions of the species （N2, N2^＋, N^＋, N） are investigated by a Monte Carlo model for nitrogen molecular gas discharge. The excitation rates of the main excited states are calculated and the corresponding relation and relative magnitude between the distribution of excitation rate of a certain excited state and the distributions of the emission rates of various lines originating from this excited level are also explored. The simulated results are compared with the experimental measurements in two typical discharge conditions. The luminescence mechanism of the line N2^＋： 391.4 nm is explained based on the microscopic plasma processes. The cathode glow in N2 discharge is found to be mainly caused by N^＋ impact excitation and the intensity of cathode glow decreases with the voltage. The corresponding relation between the emission rate or intensity of the 391.4 nm line and the production rate and the density of N2^＋ is also examined.
基金supported partially by DGAPA IN-105010, CONACyT 128714 of Mexico
文摘Optical emission spectroscopy （OES） was applied for plasma characterization during the erosion of asphaltene substrates. An amount of 100 mg of asphaltene was carefully applied to an electrode and exposed to air-plasma glow discharge at a pressure of 1.0 Torr. The plasma was generated in a stainless steel discharge chamber by an ac generator at a frequency of 60 Hz, output power of 50 W and a gas flow rate of 1.8 L/min. The electron temperature and ion density were estimated to be 2.15±0.11 eV and （1.24±0.05）× 10^16 m^-3, respectively, using a double Langmuir probe. OES was employed to observe the emission from the asphaltene exposed to air plasma. Both molecular band emission from N2, N2＋, OH, CH, NH, O2 as well as CN, and atomic light emission from V and Hγ were observed and used to monitor the evolution of asphaltene erosion. The asphaltene erosion was analyzed with the aid of a scanning electron microscope （SEM） equipped with an energy dispersive X-ray （EDX） detector. The EDX analysis showed that the time evolution of elements C, O, S and V were similar and the chemical composition of the exposed asphaltenes remained constant. Particle size evolution was measured, showing a maximum size of 2307 μm after 60 min. This behavior is most likely related to particle agglomeration as a function of time.
文摘电解液阴极大气压辉光放电-原子发射光谱ELCAD-AES是一种新兴的快速、高效、实时、在线的元素分析方法。将ELCAD-AES技术应用于水体中金属元素检测,选取K I 766.5 nm,Ca I 422.7 nm,Zn I 213.8 nm和Pb I 405.78nm为分析谱线,Hβ为内标谱线,分别建立基本定标法和内标法的光谱分析定标曲线,对4种元素的检验样品进行测定。实验结果表明,K,Ca,Zn和Pb基本定标曲线拟合度R2分别为0.9951,0.9985,0.9917和0.9934,相对误差为1.1%和2.4%,1.2%和0.94%,8.3%和0.83%,4.0%和1.9%;采用内标法,4种元素定标曲线的拟合度分别达到0.996,0.9996,0.9994和0.9996,相对误差可达到0.25%和1.8%,0.44%和0.34%,2.6%和0.19%,2.4%和0.94%。说明内标法可提高定标曲线的拟合度,减少定量分析误差,提高测量精度。
文摘Depth profiles of absorbed hydrogen introduced by electrochemical charging and light elements were analyzed in Ni-Nb-Zr-H amorphous alloy ribbons using a glow discharge optical emission spectrometer. It was clarified that the absorbed hydrogen was comparatively well-distributed on the sample surface and that the content of the hydrogen decreased with increasing depth from the surface. That is, the amount of absorbed hydrogen on the surface was about 17 at %, while that inside the specimens decreased to several atomic percent. The depth profiles of the hydrogen which were close to the surface were slightly different between those on the roller side and those on the free side in the melt-spun ribbon. The difference is thought to originate from the existence of oxygen impurity on the surface and from the difference of the Zr content.
