【作者】 李霞；

【导师】 毕卫红； 金娃；

【作者基本信息】 燕山大学 ， 光学工程， 2024， 博士

【摘要】 在海洋大气环境中,氯离子的存在对海洋设备的金属构件以及沿海地区的建筑物均构成显著的腐蚀影响。这种腐蚀不仅影响了海上航行工具的使用寿命,还影响了海岸上电子设备的运行效能及使用寿命。因此,检测海洋大气环境中氯离子的浓度对减轻海洋大气的危害具有重要意义。传统的氯离子检测方法依赖于人工操作,通常是先采集海洋大气,然后将采集到的样品在实验室中进行检测,这一检测方法过程复杂,不仅易受人为因素和电磁干扰的影响,且存在检测精度较低的问题。因此,研究抗干扰能力强、操作简单且精确度高的检测方法至关重要,本文主要对氯离子检测方法的检测机理、制备方法和性能进行了研究。首先,研究了基于法布里-珀罗干涉的氯离子光纤探针的检测机理、制备方法与实验特性。通过仿真模拟方法,研究了银/海藻酸盐复合聚合物在吸附氯离子后,法布里-珀罗腔的腔长与折射率变化对干涉光谱的影响;采用溶胶-凝胶法制备了银/海藻酸盐复合聚合物,并以此为基础构建了基于法布里-珀罗干涉的氯离子光纤探针;对该探针的灵敏度、重复性、稳定性、选择性、p H值、响应时间以及温度响应等关键性能参数进行了分析,在1～9μM的氯离子浓度范围内,灵敏度为1.471 29 nm/μM,且有良好的重复性与稳定性,并研究了法布里-珀罗腔的腔长对氯离子灵敏度的影响;鉴于温度对光纤探针性能产生的交叉影响,研究了两种有效的温度补偿方法,第一种方法是通过将光纤布拉格光栅与法布里-珀罗干涉光纤探针进行级联,在实验过程中补偿温度变化对测量结果的影响;第二种方法是运用优化后的反向传播神经网络模型,对法布里-珀罗干涉光纤探针的实验数据进行处理,对氯离子浓度进行预测,预测精度为1.21%。其次,研究了基于倏逝波氯离子光纤探针的检测机理、制备方法与特性。采用了光线追迹方法对锥形光纤进行了理论分析,同时模拟了不同锥形长度下的荧光信号功率变化,为设计优化提供了理论依据;制备了氮化碳/银离子的荧光材料,并采用提拉法将其均匀地涂覆于锥形光纤表面,制成了对氯离子敏感的倏逝波荧光光纤探针;对该探针的灵敏度、重复性、稳定性、选择性、p H值、响应时间以及温度响应等性能进行了分析,当氯离子浓度在1～9μM的范围内时,具有良好的重复性与稳定性,响应灵敏度为40.841 19/μM,并研究了涂覆于锥形光纤上的荧光材料厚度对传感性能的影响。最后,将倏逝波荧光光纤探针与光电系统进行集成化处理构成氯离子传感器的实验样机。设计了集成化的光路、电路部分与控制算法,实现对传感器的制备与控制;对传感器的氯离子浓度响应、重复性和稳定性进行了实验测试,建立了氯离子浓度的标定拟合曲线,分析了传感器在氯离子浓度测量中的相对误差。更多还原

【Abstract】 In the marine atmospheric environment,chloride ion has a significant corrosive effect on the metal components of marine equipment and on buildings in coastal areas.Such corrosion affects not only the service life of marine navigation equipment,but also the operational efficiency and service life of coastal electronic equipment.Therefore,it is important to detect the concentration of chloride ion in the marine atmospheric in order to mitigate the hazards of the marine atmosphere.The traditional method of chloride ion detection relies on manual operation,which involves collecting samples from the marine atmosphere and testing the collected samples in the laboratory.This detection method is complicated,not only susceptible to the influence of human factors and electromagnetic interference,but also has the problem of low detection accuracy.Therefore,it is important to develop detection method with strong anti-interference ability,simple operation and high accuracy.In this paper,the detection mechanism,preparation method and performance of the chloride ion detection method are mainly studied.Firstly,the detection mechanism,preparation method and properties of a fiber optic probe for chloride ion based on Fabry-Perot interference were investigated.The effect of changes in the length and refractive index of the Fabry-Perot cavity on the interference spectra of the silver/alginate composites polymer after adsorption of chloride ion was investigated by simulation methods;subsequently,the silver/alginate composite polymer was prepared by sol-gel method,and used as the basis for the construction of fiber optic probe for chloride ion based on Fabry-Perot interference;the key performance parameters such as sensitivity,repeatability,stability,selectivity,p H,response time and temperature response were analysed for this probe,the sensitivity was 1.471 29 nm/μM with good repeatability and stability in the concentration range of 1～9μM of chloride ion,and the effect of the length of the Fabry-Perot cavity on the sensitivity to chloride ion was further explored;in view of the influence of temperature on the performance of the fiber optic probe,two effective methods of temperature compensation were investigated,the first method was to compensate the effect of temperature by cascading the Fiber Bragg Grating with the Fabry-Perot interference fiber optic probe,the second method used an optimised back-propagation neural network model to process the experimental data from the Fabry-Perot interference fiber optic probe to predict the chloride ion concentration with a prediction accuracy of 1.21%.Secondly,the detection mechanism,preparation method and properties of fiber optic probe for chloride ion based on evanescent wave was investigated.The theoretical analysis of the tapered optical fiber was carried out using the ray tracing method,and the changes of the fluorescence signal power at different tapered lengths was simulated,which provided a theoretical basis for the design optimization;the fluorescent material of carbon nitride/silver ion was prepared and uniformly coated on the surface of the tapered optical fiber by lifting and pulling method to make evanescent wave fluorescent optical fiber probe sensitive to chloride ion;the sensitivity,repeatability,stability,selectivity,p H,response time and temperature response of this probe were investigated,and the response sensitivity was 40.841 19/μM with good repeatability and stability over the chloride ion concentration range of 1～9μM,and the effect of the thickness of the fluorescent material coated on the tapered optical fibre on the sensing performance was studied.Finally,the evanescent wave fluorescent fiber optic probe was integrated with the optoelectronic system to form an experimental prototype of chloride ion sensor.The integrated optical circuit,circuit part and control algorithm were designed to realize the preparation and control of the sensor;the response,repeatability and stability of the sensor for chloride ion were tested experimentally and the calibration fit curve was established to analyze the relative error in measuring chloride ion concentration.更多还原