For sensitive and accurate methane (CH) and ethane (CH) simultaneous detection, a near-infrared dual-gas sensing system based on wavelength modulation spectroscopy (WMS) was developed. A fiber-coupled distributed feedback (DFB) diode laser emitting at 1.684 μm was employed as light source. The scanning and modulation signals applied to the injection current of the laser were designed based on time division multiplexing (TDM) to realize the dual-gas measurement. A White cell with absorption path length of 16 m was utilized. The light intensity signal detected was processed with python based digital quadrature lock-in amplifier to obtain first and second harmonic signals. Allan deviation analysis yielded detection limits of 23.53 ppb for CH and 146.4 ppb for CH in an average time of 100 s.
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http://dx.doi.org/10.1016/j.saa.2022.120970 | DOI Listing |
RSC Adv
November 2024
Department of Mechanical Engineering, Faculty of Engineering, Universitas Diponegoro Semarang 50275 Central Java Indonesia
Developing efficient and reliable gas sensors for the simultaneous detection of multiple gases is paramount in various fields, specifically healthcare, biological, and biomedical applications. In this study, we present a novel ratiometric optical dual gas sensor based on perovskite quantum dots (PQDs) to detect nitric oxide and oxygen simultaneously. All dye molecules were excited using a 405 nm LED in the experimental setup.
View Article and Find Full Text PDFACS Sens
December 2024
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
Sulfur dioxide (SO) and nitrogen dioxide (NO) are chemical indicators of crop straw combustion as well as significant atmospheric pollutants. It is challenging to promptly detect natural "wildfires" during agricultural production, which often lead to uncontrollable and substantial economic losses. Moreover, both "wildfires" and artificial "straw burning" practices pose severe threats to the ecological environment and human health.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
February 2025
Laser Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.
In the quantitative analysis of mixed gases by tunable diode laser absorption spectroscopy, the overlapping of absorption spectra and mutual interference of multi-component gases can lead to problems of large measurement errors and low analysis accuracy. In this paper, an improved firefly algorithm is proposed and applied to the support vector machine regression model to solve this problem. The specific method includes introducing an adaptive step size to balance the local and global searches and using the gradient descent method to accelerate the parameter optimization process so as to improve the model's generalization ability and prediction accuracy.
View Article and Find Full Text PDFA novel double spot-ring plane-concave multipass cell (DSPC-MPC) gas sensor was proposed for simultaneous detection of trace gases, which has lower cost and higher mirror utilization than the traditional multipass cell with 129 m, 107 m, 85 m, 63 m and 40 m effective optical path lengths adjustable. The performance of the DSPC-MPC gas sensor was evaluated by measuring CO and CH4 using two narrow linewidth distributed feedback lasers with center wavelengths of 1567 nm and 1653 nm, respectively. An adjustable digital PID laser frequency stabilization system based on LabVIEW platform was developed to continuously stabilize the laser frequency within ∼±30.
View Article and Find Full Text PDFLight Sci Appl
May 2024
National Key Laboratory of Laser Spatial Information, Harbin Institute of Technology, Harbin, China.
Photoacoustic spectroscopy (PAS) as a highly sensitive and selective trace gas detection technique has extremely broad application in many fields. However, the laser sources currently used in PAS limit the sensing performance. Compared to diode laser and quantum cascade laser, the solid-state laser has the merits of high optical power, excellent beam quality, and wide tuning range.
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