Open-path sensor based on QCL for atmospheric N2O measurement

Zhang, Yurong; Ding, Jialin; Zhang, Xiaojie; Fang, Jing; Zhao, Yuefeng

doi:10.1016/j.rinp.2021.104909

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…To enhance the resolution of these systems, QCLs have been integrated with photoacoustic spectroscopy (PAS), tunable IR laser differential absorption spectroscopy (TILDAS), wavelength modulation spectroscopy (WMS), multipass cells, and quartz-enhanced. ,,− These additions all aided in portability through either being convenient and capable of continuous measurements or reducing the physical size of the transducer using the piezoelectric effect. That said, these enhanced systems are not without their problems such as sensitivity to vibrations or noise and humidity.…”

Section: Portable N2o Sensorsmentioning

confidence: 99%

Nitrous Oxide Is No Laughing Matter: A Historical Review of Nitrous Oxide Gas-Sensing Capabilities Highlighting the Need for Further Exploration

Milam-Guerrero

Yang

et al. 2022

ACS Sens.

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Nitrous oxide (N 2 O), also known as laughing gas, is arguably one of the most detrimental greenhouse gases while concurrently being overlooked by the public. Specifically, N 2 O is ∼300 times more damaging than its better-known counterpart carbon dioxide (CO 2 ) and has a longer-lived lifetime in the atmosphere than CO 2 . There exist both natural and anthropogenic sources of N 2 O, and thus, for a better understanding of sources, capture, and decomposition, it is pivotal to identify N 2 O within the nitrogen biosphere. This review covers the past and current low-cost N 2 O gas-sensing technologies, focusing specifically on low-cost metal oxide semiconductors (MOSs), chemiresistive and electrochemical sensors that can provide spatial and temporal monitoring of N 2 O emissions from various sources. Additionally, compositional modifications to MOsS using metal− organic frameworks (MOFs) are discussed, potentially facilitating new awareness and efforts for increased sensing performance and functionality in N 2 O detection.

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Section: Portable N2o Sensorsmentioning

confidence: 99%

Nitrous Oxide Is No Laughing Matter: A Historical Review of Nitrous Oxide Gas-Sensing Capabilities Highlighting the Need for Further Exploration

Milam-Guerrero

Yang

et al. 2022

ACS Sens.

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“…Laser absorption spectroscopy (LAS) has been applied in various fields such as atmospheric environment monitoring [1,2], biomedical research [3,4] , and industrial process control [5] due to its advantages of fast response time, non-invasiveness, high sensitivity and high resolution. In the case of in-situ measurements [6] , temperature and pressure-induced changes in absorption line broadening can prevent the harmonic signals from always being at the optimal modulation coefficients, vibration-induced fluctuations in the detector's effective beam-receiving area, as well as changes in the refractive index of the turbulence as it passes through atmospheric molecular clusters cause scintillation effects in the laser, causing fluctuations in the laser light intensity. These factors affect the amplitude of the harmonic signals and the results of concentration inversion, which ultimately affects the accuracy and stability of the in-situ measurement system.…”

Section: Introductionmentioning

confidence: 99%

Data processing method for improving the in-situ detection performance of flue gas concentration in laser modulation spectroscopy

Cai,

Zhang,

et al. 2024

Advanced Fiber Laser Conference (AFL2023)

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In-situ laser absorption spectroscopy is commonly used for environmental monitoring and industrial process control, but fluctuations in field environmental conditions can affect measurement accuracy and stability. In the wavelength modulated spectroscopy (WMS) technique, the first harmonic or DC signal is often used for light intensity normalization, which to a certain extent weakens the influence of light intensity fluctuations caused by vibration, turbulence, etc. in the measurement optical path. However, the simultaneous extraction of different harmonic signals from the same absorbed spectrum using a lock-in amplifier requires at least two channels, and the inconsistency between the channels increases the complexity and uncertainty of the system. Therefore, a harmonic extraction method based on the short-time Fourier transform (STFT) is proposed, in which the discrete Fourier transform (DFT) is performed on the signal segment by segment by shifting the window function, and the DC component and the harmonic signals of each order can be extracted simultaneously according to the multiples of the modulation frequency. The effectiveness of this method is verified in the experimental system of CO2 in-situ measurement of laser absorption spectroscopy, and the results show that the relative errors of the harmonic signals extracted by the method in this paper are always kept within 0.6%, and the average time saved is about 34.62%.

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“…Gases are often produced in industrial processes, such as boiler furnaces and aviation engine nozzles, and they are closely related to system safety and production efficiency [1,2]. However, gases are often characterized as invisible and intangible, making it difficult for people to detect their presence.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Reconstruction of Gas Concentration and Temperature Using Acoustic Tomography

Liu,

Zhu,

Deng

et al. 2024

Sensors

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Acoustic tomography utilizes sensor arrays to collect sound wave signals, enabling non-contact measurement of physical parameters within an area of interest. Compared to optical technologies, acoustic tomography offers the advantages of low cost, low maintenance, and easy installation. Current research in acoustic tomography mainly focuses on reconstruction algorithms for temperature fields, while monitoring the composition and concentration of gases is significant for ensuring safety and improving efficiency, such as in scenarios like boiler furnaces and aviation engine nozzles. In excitable gases, the speed of sound exhibits an S-shaped curve that changes with frequency, a characteristic that could be potentially useful for acoustic tomography. Therefore, this study primarily discusses the quantitative calculation of gas concentration and temperature based on the dispersion of the speed of sound. By employing graphic processing and pattern matching methods, a coupled relationship of the dispersion of the speed of sound with gas concentration and temperature is established. The projection intersection method is used to calculate the concentration and temperature of binary and ternary gas mixtures. Combined with the inversion method, a joint reconstruction method for gas concentration fields and temperature fields based on the dispersion of the speed of sound is developed. The feasibility of the proposed simultaneous reconstruction method for temperature and concentration fields is validated using numerical simulations. Additionally, an acoustic tomography experimental system was set up to conduct reconstruction experiments for binary gas concentration fields and temperature fields, confirming the effectiveness of the proposed method.

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Open-path sensor based on QCL for atmospheric N2O measurement

Cited by 7 publications

References 19 publications

Nitrous Oxide Is No Laughing Matter: A Historical Review of Nitrous Oxide Gas-Sensing Capabilities Highlighting the Need for Further Exploration

Nitrous Oxide Is No Laughing Matter: A Historical Review of Nitrous Oxide Gas-Sensing Capabilities Highlighting the Need for Further Exploration

Data processing method for improving the in-situ detection performance of flue gas concentration in laser modulation spectroscopy

Simultaneous Reconstruction of Gas Concentration and Temperature Using Acoustic Tomography

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