摘 要
近年来，环境污染的治理逐渐成为世界关注的焦点问题，而污染物的监测是环境保护、控制治理污染的前提。一氧化碳是无色、无臭、无味、有毒的气体，标准状况下气体密度为l.25g/L,和空气密度(标准状况下)1.293g/L相差很小，这也是容易发生煤气中毒的因素之一。它为中性气体，不易溶于水而且化学性质稳定，如果大气中一氧化碳含量过高，人类就可能会面临灭顶之灾。
通过对一氧化碳气体浓度的检测技术的研究，可以使我们有效地控制其排放，也可以为在线监测其它污染气体打下良好的坚实理论和实验基础。
本文基于可调谐激光二极管技术（TDLAS）用于气体浓度检测的基本原理。通过测得的10组标准一氧化碳浓度及其二次谐波数据，进行数据拟合，为工程上运用TDLAS检测气体浓度提供简便的一氧化碳浓度反演，从而能实时地监控一氧化碳浓度。
本文分析了已测量的标准一氧化碳二次谐波数据，通过选取最佳拟合位置，并对几种常用拟合方法进行比较，从而得到最佳的拟合效果。本论文通过类比方法，重点对拟合参量的选取分析及拟合方法作比较。随机选取几组数据进行拟合，另外的几组用作检验误差。最后得出结论：用二次谐波最值之差做拟合点，并结合二阶最小二乘法进行拟合后的效果最佳。
在确定选取二阶最小二乘法进行数据拟合后，重新选取了拟合数据和检验数据作比较。得出结论：拟合结果跟数据的选取有关，但总趋势一致。
关键字:一氧化碳，TDLAS，二次谐波，拟合，浓度反演
Abstract
In recent years, environmental pollution control has become the focus of world’s attention.However, the premise of environmental protection and pollution control is monitoring of those pollutants. Carbon Monoxide is a colorless, odorless, tasteless, poisonous gas, its density,under standard conditions,is l.25g / L, and compare with the air’s density (standard conditions is 1.293g / L) ,the difference is so small.It is also one of the answer that Carbon Monoxide is prone to cause gas poisoning. It is a neutral gas, easily soluble in water and its chemical properties is stable,too.If high levels emission of Carbon Monoxide is in the atmosphere, humans may face an extinction.
To study the technology of carbon monoxide concentration
detection ,not only allows us to control its emissions effectively, but also to control other polluting gases online monitoring ,and lay a good solid theoretical and experimental basis for the future's study.
This text is based on the basic principles of the use of the tunable laser diode technology for gas detection. To deal with the measured concentration of Carbon Monoxide and 10 groups of standard second harmonic data, we use data fitting, and ,in this way ,we can provide a simple method to calculate carbon monoxide’s concentration for the project on the use of TDLAS gas concentration detection ,which can monitor the real-time concentration of Carbon Monoxide.
To get the best fitting results ,this article analyzes the measured data of Carbon Monoxide in the second harmonic standard, by selecting the best fitting position and the best fitting methods. In this paper,
through analogy methods, we emphasis on the selection of fitting parameters and fitting methods for comparison. Several groups of randomly selected to fit the data, the others for error test. We get the final conclusion: the best fit points is the The difference between the maximum and minimum values of the second harmonic data, combining with second-order method of least squares .
When determine the second least-squares method is the best method for data fitting, we re-selected a group of fitting data and test data to make a comparison. We ge that the fitting result is just a little matter with the data’s selection.
Keywords: Carbon Monoxide, TDLAS, second harmonic, fitting, concentration inversion
目录
摘 要 I
Abstract II
1绪 论 1
1.1研究背景与意义 1
1.2研究现状 2
1.3本文主要内容 3
基于可调谐二极管激光吸收光谱的气体浓度反演方法
