土壤呼吸作用红外光谱传感方法研究及监测系统设计

发布时间：2018-06-06 15:04

本文选题：土壤呼吸作用 + 红外光谱　；参考：《安徽大学》2015年硕士论文

【摘要】：土壤呼吸作用作为全球陆地生态系统中最大的碳库和碳循环过程的重要组成部分,往往可以作为土壤质量和土壤肥力的重要生物学指标和土壤健康状况的指示因子。因此,对土壤呼吸作用的研究和实时监测不仅是准确评估全球碳收支平衡的关键,而且对于当前碳循环的研究以及减缓全球温室效应的进程具有重要意义。现有的土壤呼吸作用监测装置,如美国LI-COR公司的Li-8100和Li-6400,这些土壤呼吸作用监测设备价格昂贵,便携性较差,在很大程度上限制了它的普及和发展,基于以上不足,本论文主要研究目标是设计一款重复性和稳定性较好、价格低廉、使用方便快捷的便携式土壤呼吸作用监测系统。首先,本文研究了红外光谱传感方法,其中峰高测量方法为气体传感器定量化提供了理论依据,长光程理论为气体传感器气室的创新设计提供了理论基础。通过土壤呼吸作用实验,证明了土壤呼吸作用释放气体的主要成分是二氧化碳气体。通过气体红外光谱与NIST谱库作对比分析,选取了定量分析二氧化碳气体的特征波长为4.26μm。其次,通过前期的理论和技术指导,设计了土壤呼吸作用监测系统的核心部件—一款基于长光程NDIR技术的土壤呼吸作用气体传感器。该传感器采用单光路双波长差分测量方法,在很大程度上减小了红外光源的不稳定性和光路干扰。传感器气室采用多次反射提高光程并结合气室镀膜技术,提高了监测系统的检测能力和灵敏度。在硬件设计方面,传感器结合外围电路组成了土壤呼吸作用监测系统核心电路板。在软件设计方面,本文使用硬件滤波结合软件滤波的方法消除信号干扰,提高了系统的测量精度。此外,本文还提出了一种土壤呼吸作用速率的循环测量方法,并编写了配套的系统软件。最后,将自主设计的基于长光程NDIR型二氧化碳气体传感器应用到土壤呼吸作用监测系统中,并对系统进行了组装；通过野外试验验证了系统设计的正确性。
[Abstract]:Soil respiration, as the largest carbon pool and carbon cycle in the global terrestrial ecosystem, is often used as an important biological index of soil quality and soil fertility and an indicator of soil health. Therefore, the study of soil respiration and real-time monitoring is not only the key to accurately assess the global carbon balance, but also important for the current study of carbon cycle and slowing down the process of global Greenhouse Effect. The existing soil respiration monitoring devices, such as Li-8100 and Li-6400 of LI-COR Corporation in the United States, are expensive and less portable, limiting its popularity and development to a large extent. The aim of this paper is to design a portable soil respiration monitoring system with good repeatability and stability, low price and convenience. Firstly, the infrared spectrum sensing method is studied, in which the peak height measurement method provides the theoretical basis for the gas sensor quantification, and the long optical path theory provides the theoretical basis for the innovative design of the gas sensor chamber. Through soil respiration experiments, it is proved that the main component of soil respiration releasing gas is carbon dioxide gas. The characteristic wavelength of quantitative analysis of carbon dioxide gas is 4.26 渭 m, which is compared with NIST spectrum library. Secondly, the core component of soil respiration monitoring system, which is based on long-path NDIR technology, is designed based on the previous theoretical and technical guidance. The sensor uses single optical path and double wavelength differential measurement method to reduce the instability and optical path interference of infrared light source to a great extent. The detection ability and sensitivity of the monitoring system are improved by using multiple reflectors to improve the optical path and combined with the coating technology of the gas chamber. In the aspect of hardware design, the core circuit board of soil respiration monitoring system is composed of sensor and peripheral circuit. In the aspect of software design, the hardware filter combined with software filter is used to eliminate the signal interference and improve the measuring accuracy of the system. In addition, a cyclic measurement method of soil respiration rate is proposed and a complete system software is developed. Finally, the self-designed carbon dioxide gas sensor based on long-path NDIR is applied to the soil respiration monitoring system, and the system is assembled, and the correctness of the system is verified by field experiments.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154;TP274

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