| 基于谐波检测原理的双光路光纤气体传感系统研究电子书、 摘 要 近年来，煤矿生产事故频发，且以瓦斯爆炸为主，给矿工生命和国家财产安全造成严重威胁。大气污染已经严重影响人民的健康和生活。对于瓦斯、一氧化碳，硫化氢等有害气体来说，迫切需要一种安全有效的气体检测系统。光纤气体传感技术是一项正在发展中的高精度测试技术。论文以气体浓度检测为目的，进行基于近红外吸收原理的光纤气体传感技术的研究。论文的主要工作如下：首先，论述了近红外吸收型光纤气体传感器的国内外研究现状和发展趋势，分析了光纤气体传感中的影响因素和关键技术。通过对分子光谱理论的分析，给出气体吸收测量的理论基础，为传感器数学模型的建立奠定理论基础。其次，针对气体在近红外波段吸收弱的特点，把光谱调制技术用于浓度检测。详细论述了波长调制和谐波检测的基本原理，并给出了检测微弱信号的锁相放大技术，实现了所测信号的提取和放大。通过数值模拟确定了谐波次数的选取，分析了基于窄带光源(DFBLD)和宽带光源(LED)波长调制技术的检测原理，建立了谐波检测的数学模型和基于谐波检测原理的双光路检测方案。最后，阐述了甲烷检测系统中光源、气室、光电探测器以及光路部分和电信号检测部分的特性及对测量的影响，设计了基于谐波检测原理的双光路气体传感器理论模型机，可以降低成本，为气体检测仪器实用化奠定基础。测量了光源光谱特性，对甲烷近红外吸收特性，检测信号和气体浓度的关系以及系统的重复性和稳定性进行了实验研究，给出了实验结果，验证了检测系统和模型机的可行性。 关键词 近红外吸收；波长调制技术；光纤布拉格光栅；压电陶瓷；锁相放大技术；二次谐波检测；甲烷 目 录 摘要·····················································································································I Abstract············································································································· II 第1 章 绪论·······································································································1 1.1 课题研究的背景与意义··········································································1 1.2 气体检测方法概述··················································································2 1.3 光纤气体传感技术··················································································2 1.4 光纤气体传感器的分类··········································································3 1.4.1 光谱吸收型光纤气体传感器···························································3 1.4.2 折射率变化型光纤气体传感器·······················································5 1.4.3 荧光型光纤气体传感器···································································6 1.4.4 染料指示剂型光纤气体传感器·······················································7 1.4.5 弹光型光纤气体传感器···································································8 1.4.6 多点复用型光纤气体传感器···························································8 1.5 光谱吸收型光纤气体传感器的研究历史与现状···································9 1.6 课题研究的目的和意义········································································ 11 1.7 论文的主要研究内容············································································ 11 第2 章 光纤气体检测机理·············································································13 2.1 引言········································································································ 13 |
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