高压甲烷近红外吸收光谱展宽特性及参数精确测量
投稿时间:2020-02-19  修订日期:2020-03-25  点此下载全文
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作者单位E-mail
何莹 中国科学院安徽光学精密机械研究所 heying@aiofm.ac.cn 
张玉钧 中国科学院安徽光学精密机械研究所 yjzhang@aiofm.ac.cn 
尤坤 中国科学院安徽光学精密机械研究所  
范博强 中国科学院安徽光学精密机械研究所中国科学技术大学  
李梦琪 中国科学院安徽光学精密机械研究所中国科学技术大学  
余冬琪 中国科学院安徽光学精密机械研究所中国科学技术大学  
谢皓 中国科学院安徽光学精密机械研究所中国科学技术大学  
雷博恩 中国科学院安徽光学精密机械研究所中国科学技术大学  
贾巍 安徽建筑大学  
经俊森 安徽建筑大学  
刘文清 中国科学院安徽光学精密机械研究所  
基金项目:国家自然科学基金(编号4180512)、安徽省重点研发项目(编号201904a07020093)、安徽省自然科学基金项目(编号1808085MD107、编号1808085QD113)、安徽省高校自然科学研究重点项目(编号KJ2019A0793)和安徽建筑大学科研项目(编号JZ192037)
中文摘要:高压气体吸收光谱的压力展宽特性是气体高分辨光谱特性重要组成,也是气体激光光谱技术应用的基础。通过搭建的检测实验平台,获取了甲烷6046.96 cm-1处高压气体吸收光谱。通过经验模态分解算法减弱高压引起的窗片形变产生的探测信号噪声,吸光度信号的均方根误差(RESM)降低了3.87倍。通过洛伦兹线型拟合算法获得吸光度信号,线型拟合残差优于±1%,并提取不同压力下气体特征吸收光谱。随后,研究了高压下甲烷吸收光谱的展宽特性。研究表明,气体吸收谱线的线宽随着压力增大而增大,高压环境的氮气-甲烷分子的互展宽系数为0.0631 cm -1atm -1。随着压力的增大,吸收线出现“红移”现象,波长中心频率与压强之间具有线性相关性,获得氮气诱导压力频移系数为-0.00848cm-1atm -1,由此提出利用检测波长、压力和压力频移系数的线性关系反演高压环境下气体浓度的算法。高压环境下吸收光谱展宽特性和浓度反演方法的研究对进一步明晰高压环境下气体高分辨吸收光谱特性,开展特殊工业环境的检测光谱研究打下基础。
中文关键词:激光吸收光谱  互展宽系数  压力频移  高压  甲烷
 
Precise measurements the Broadening Characteristics and Parameters of Methane Near-Infrared Absorption Spectrum at High Pressure
Abstract:The pressure broadening characteristic of high-pressure gas absorption spectrum is an important component of high-resolution spectrum characteristic, and it is also the foundation of gas laser spectroscopy technology application. The methane absorption spectrum at 6046.96 cm-1 at high-pressure was obtained with the detection experimental platform. The empirical mode decomposition algorithm was used to filter out the noise of the detection signal caused by the window deformation at high-pressure, that the overall root mean square error(RESM) of absorbance signal was reduced by 3.87 times. And the fitting residual error of absorption lines was lower than ±1% by using the Lorentz line-type fitting algorithm to extract the characteristic absorption spectrum under different pressures. Then, the broadening characteristics of methane absorption spectrum at high pressure were studied. Those studies show that the linewidth of gas absorption lines increases with the pressure rising, and the cross-broadening coefficient of nitrogen-methane molecules at high-pressure is about 0.0631 cm -1atm -1. Moreover, the absorption line appears a "red shift" phenomenon as pressure increasing. The pressure shift coefficient of the nitrogen-induced is about -0.00848cm -1atm -1 with the linear correlation between the laser center frequency and pressure. Therefore, a method for gas concentration inversion at high pressure was proposed by the linear relationship between the detection wavelength, pressure and pressure shift coefficient. In conclusion, the research on absorption spectrum broadening characteristics and concentration inversion method of in high-pressure environment laid foundation for further clarification of high-resolution absorption spectrum characteristics and detection spectrum study in special industrial environment.
keywords:laser absorption spectroscopy  mutual broadening coefficient  pressure shift  high pressure  methane
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