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采用发射光谱方法对大气压氩气介质阻挡放电(DBD)系统中的电子密度进行了诊断。通过考虑放电等离子体中的各种加宽机制, 采用自编的非对称卷积程序对氩原子发射谱线的线型进行分析拟合, 再通过反卷积的方法将各种加宽机制分离开来, 最终将Stark展宽分离出来进行大气压氩气介质阻挡放电电子密度的计算。诊断结果表明, 在大气压氩气介质阻挡放电中当有三个放电丝存在, 电子温度为10000 K时, 电子密度约为4.06×1021 m-3, 诊断结果和模拟结果符合得很好。此方法不仅可以应用在大气压介质阻挡放电中, 还可以用于其他含有非氢气体的大气压等离子体电子密度的测量。 相似文献
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采用激光诱导击穿光谱技术(Laser-induced b reakdown spectroscopy,LIBS)对土 壤样品中的Pb和Cr元素进行了分析,以PbI280.17 nm和CrI425.43 nm作为分析线,优化了透 镜到样品的距离(Lens to sample distance,LTSD)、延迟时间对光谱信号强度及信噪比 SNR 的影响。在最佳实验条件下,对两种元素的谱峰强度和元素浓度进行分析,针对外标法 和内标法分别建立了谱线峰值强度、谱线峰值积分面积与对应元素浓度的定标曲线。采用谱 线峰值积分面积法对土壤中重金属Pb和Cr元素的检测,相比于外标法,内标法将Pb和Cr元素 最大相对误差分别从13.56%和12.68%降低到了 6.7%;Pb和Cr元素定标曲线的拟合相关 系数R2分别从0.978和0.975提高到了0.996和0.991。实 验结果表明:采用LIBS技术对土 壤中Pb、Cr元素检测具有可行性,采用谱线峰值积分面积的内标法,可以降低最大相对误差 并提高测量精度。 相似文献
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The concentrations of CO2 were measured by the supercontinuum laser at normal temperature and variable temperature accurately in this paper. The absorption spectra of CO2 at different concentrations(1.2%—9.0%) were measured in the wavelength range of 1 425—1 445 nm under the optical path of 26.4 m at 293 K and 1 atm. The experimental results showed that the positions of the primary and secondary absorption peaks(1 432 nm, 1 437 nm) were consistent with the HITRAN database. A linear model of concentration and signal intensity at 1 432 nm was established. The maximum relative error of the concentration measurement was 3.3%. The line intensities of 99.9% CO2 in the 1 425—1 445 nm at different temperatures(298—373 K, interval of 15 K) were measured. The influence of temperature changes on the concentration measurement result was corrected and the relative error of the concentration measurement was reduced to 1.4%. Finally, the source of the uncertainty of the entire spectrum measurement system was analyzed and evaluated. This paper demonstrate that the supercontinuum laser can achieve the long-distance measurement of the CO2 under normal temperature or variable temperature environment accurately, which provide an important reference for the long-distance gas detection on site and simultaneous detection of multi-component gases. 相似文献
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A differential optical absorption spectroscopy (DOAS) method is presented and used for the air pollutant detection. The novel measurement frame employs a Cassegrain telescope and a combined fiber bundle. The emitting and receiving fibers are bundled together at one port. The common port is placed at the focus of the Cassegrain telescope. The total length of the prototype is reduced to about 1/2 of the traditional one. Air pollutants of SO2, NO2 and O3 are monitored by the prototype, and the concentrations are inverted. Results show that the correlation coefficients are 0.9490, 0.9614 and 0.9301, respectively. And there is a good consistency between the measured results and the reference data. 相似文献
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A series of Ce3+, Tb3+ or Ce3+/Tb3+ doped YAl3(BO3)4 phosphors are synthesized by a high temperature solid-state reaction, and their luminescent properties are investigated. YAl3(BO3)4:Ce3+ shows a broad emission band at 422 nm under the 367 nm radiation excitation. YAl3(BO3)4:Tb3+ can be efficiently excited by the ultraviolet (UV) light, and produces green emission. The emission intensity of YAl3(BO3)4:Tb3+ can be enhanced by adjusting Tb3+ doped content, and reaches the maximum at 0.06 mol Tb3+. When Ce3+ is codoped, the emission intensity of Tb3+ in YAl3(BO3)4 can be enhanced, but the commission international del’eclairage (CIE) chromaticity coordinates of YAl3(BO3)4:Tb3+ have almost no change. Moreover, the energy transfer from Ce3+ to Tb3+ in YAl3(BO3)4 is studied. 相似文献
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The aim of this study is to investigate the relationship between the laser-induced optical breakdown energy threshold and the spectral signal changes with the spot radius. First of all, using the avalanche breakdown threshold theory calculates the threshold avalanche ionization rate ηc. Combining with the theory of light intensity distribution and the relationship between pulse energy and peak power, numerical calculations have obtained the law of change of spot radius and threshold laser energy. Secondly, the variation of the spectral signal-to-noise ratio (SNR) with the laser energy is measured according the experimental measurement, and the threshold laser energy required for optical breakdown at different spot radius is obtained. The theoretical threshold model of the relationship between the threshold laser energy and the quadratic function of the spot radius obtained by numerical calculation is verified, and it is revised, the results show that the relative error between the revised theoretical threshold model and the experimental threshold model is less than 5.3%. At last, the influence of the spot radius on the spectral signal and electron density is also analyzed, it is found that both the spectral intensity and the electron density have a maximum at the spot radius of 11 μm. The results show that it is necessary to find the best spot radius during the laser induced breakdown spectroscopy (LIBS) experiment. This provides a reliable theoretical basis and experimental reference for further study of the influence of spot radius on LIBS technology measurement. 相似文献