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Yin S, Zou X, Cheng Y, Liu Y. Temperature Compensation of Laser Methane Sensor Based on a Large-Scale Dataset and the ISSA-BP Neural Network. SENSORS (BASEL, SWITZERLAND) 2024; 24:493. [PMID: 38257586 PMCID: PMC10819906 DOI: 10.3390/s24020493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/30/2023] [Accepted: 01/09/2024] [Indexed: 01/24/2024]
Abstract
We aimed to improve the detection accuracy of laser methane sensors in expansive temperature application environments. In this paper, a large-scale dataset of the measured concentration of the sensor at different temperatures is established, and a temperature compensation model based on the ISSA-BP neural network is proposed. On the data side, a large-scale dataset of 15,810 sets of laser methane sensors with different temperatures and concentrations was established, and an Improved Isolation Forest algorithm was used to clean the large-scale data and remove the outliers in the dataset. On the modeling framework, a temperature compensation model based on the ISSA-BP neural network is proposed. The quasi-reflective learning, chameleon swarm algorithm, Lévy flight, and artificial rabbits optimization are utilized to improve the initialization of the sparrow population, explorer position, anti-predator position, and position of individual sparrows in each generation, respectively, to improve the global optimization seeking ability of the standard sparrow search algorithm. The ISSA-BP temperature compensation model far outperforms the four models, SVM, RF, BP, and PSO-BP, in model evaluation metrics such as MAE, MAPE, RMSE, and R-square for both the training and test sets. The results show that the algorithm in this paper can significantly improve the detection accuracy of the laser methane sensor under the wide temperature application environment.
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Affiliation(s)
- Songfeng Yin
- School of Electronics and Information Engineering, Anhui Jianzhu University, Hefei 230601, China; (S.Y.); (Y.L.)
- Hefei Institute for Public Security, Tsinghua University, Hefei 230601, China;
- Hefei Tsingsensor Technology Co., Ltd., Hefei 230601, China
| | - Xiang Zou
- School of Electronics and Information Engineering, Anhui Jianzhu University, Hefei 230601, China; (S.Y.); (Y.L.)
| | - Yue Cheng
- Hefei Institute for Public Security, Tsinghua University, Hefei 230601, China;
- Hefei Tsingsensor Technology Co., Ltd., Hefei 230601, China
| | - Yunlong Liu
- School of Electronics and Information Engineering, Anhui Jianzhu University, Hefei 230601, China; (S.Y.); (Y.L.)
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Gu M, Chen J, Zhang Y, Tan T, Wang G, Liu K, Gao X, Mei J. Portable TDLAS Sensor for Online Monitoring of CO 2 and H 2O Using a Miniaturized Multi-Pass Cell. SENSORS (BASEL, SWITZERLAND) 2023; 23:2072. [PMID: 36850670 PMCID: PMC9963767 DOI: 10.3390/s23042072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/04/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
We designed a tunable diode laser absorption spectroscopy (TDLAS) sensor for the online monitoring of CO2 and H2O concentrations. It comprised a small self-design multi-pass cell, home-made laser drive circuits, and a data acquisition circuit. The optical and electrical parts and the gas circuit were integrated into a portable carrying case (height = 134 mm, length = 388 mm, and width = 290 mm). A TDLAS drive module (size: 90 mm × 45 mm) was designed to realize the function of laser current and temperature control with a temperature control accuracy of ±1.4 mK and a current control accuracy of ±0.5 μA, and signal acquisition and demodulation. The weight and power consumption of the TDLAS system were only 5 kg and 10 W, respectively. Distributed feedback lasers (2004 nm and 1392 nm) were employed to target CO2 and H2O absorption lines, respectively. According to Allan analysis, the detection limits of CO2 and H2O were 0.13 ppm and 3.7 ppm at an average time of 18 s and 35 s, respectively. The system response time was approximately 10 s. Sensor performance was verified by measuring atmospheric CO2 and H2O concentrations for 240 h. Experimental results were compared with those obtained using a commercial instrument LI-7500, which uses non-dispersive infrared technology. Measurements of the developed gas analyzer were in good agreement with those of the commercial instrument, and its accuracy was comparable. Therefore, the TDLAS sensor has strong application prospects in atmospheric CO2 and H2O concentration detection and ecological soil flux monitoring.
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Affiliation(s)
- Mingsi Gu
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
| | - Jiajin Chen
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Yiping Zhang
- Anhui Advanced Spectroscopy Optical-Electric S&T Co., Ltd., Hefei 230026, China
| | - Tu Tan
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Guishi Wang
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Kun Liu
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Xiaoming Gao
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Science Island Branch of Graduate School, University of Science and Technology of China, Hefei 230026, China
| | - Jiaoxu Mei
- Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
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Wang R, Peng J, Chen J, Ti C, Wang G, Liu K, Gao X. Standoff sub-ppb level measurement of atmospheric ammonia with calibration-free wavelength modulation spectroscopy. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 286:121929. [PMID: 36219963 DOI: 10.1016/j.saa.2022.121929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Ammonia (NH3) plays a significant role in the formation of atmospheric particulate matter, and influences on environmental and public health as well as climate change. Thus, it is important to sensitive measurement of atmospheric NH3. In the present work, a sub-ppb level standoff open-path NH3 sensor was developed for on line, sensitive measurement of atmospheric NH3. A 9.06 μm distributed feedback quantum cascade laser was employed to probe the ammonia absorption lines located on fundamental rotational-vibrational absorption band and calibration-free wavelength modulation spectroscopy technique was employed to retrieve NH3 concentration directly. The standoff open-path NH3 sensor performance was investigated in laboratory corridor with 80 m open path length (Hefei, China) and a minimum detection limit of 0.46 ppb (3σ) was obtained. Finally, field campaign measurement was carried out in a winter wheat farmland (Changshu, China). Field measurement shown that the concentration of NH3 varies from 7 ppb to 30 ppb with an average of 14 ppb. The developed standoff sensor has high potential to be a robust tool for monitoring atmospheric NH3 or study of regional ammonia emissions in farmland or feedlot scale.
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Affiliation(s)
- Ruifeng Wang
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
| | - Jie Peng
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
| | - Jiajin Chen
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Chaopu Ti
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Guishi Wang
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
| | - Kun Liu
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Xiaoming Gao
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China, Hefei 230026, China
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Wang R, Peng J, Cao Y, Mei J, Wang G, Liu K, Chen W, Gao X. Double-enhanced multipass cell-based wavelength modulation spectroscopy CH 4 sensor for ecological applications. OPTICS EXPRESS 2023; 31:3237-3248. [PMID: 36785320 DOI: 10.1364/oe.480496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
A novel CH4 sensor based on wavelength modulation spectroscopy with a multipass cell was developed for the soil respiration measurement of CH4. A home-made double-enhanced Herriot-type multipass cell with an effective absorption length of 73.926 m and a fiber-coupled distributed feedback diode laser emission at 1653.74 nm were used to design the sensor. The double enhancement of the effective optical pathlength of the multipass cell, absorption line locking, laser intensity normalization, and temperature control of the multipass cell were used to improve cell performance and achieve a minimum detection limit of 10 ppbv and a measurement precision of 6.4 ppbv. Finally, the potential of the developed CH4 sensor for ecological applications was verified by measuring the soil respiration of CH4 and monitoring of CH4 in the atmosphere over a long period.
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Gu M, Chen J, Mei J, Tan T, Wang G, Liu K, Liu G, Gao X. Open-path anti-pollution multi-pass cell-based TDLAS sensor for the online measurement of atmospheric H 2O and CO 2 fluxes. OPTICS EXPRESS 2022; 30:43961-43972. [PMID: 36523082 DOI: 10.1364/oe.474070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/29/2022] [Indexed: 06/17/2023]
Abstract
We report an open-path and anti-pollution multi-pass cell based tunable diode laser absorption spectroscopy (TDLAS) sensor, which was designed for online measurement of atmospheric H2O and CO2 fluxes. It is mainly composed of two plano-convex mirrors coated on a convex surface, which makes it different from traditional multi-pass cells. This design does not allow a direct contact between the coating layer of the lens and air, thereby realizing the anti-pollution effect of the coating layer. Two DFB lasers operating at 1392 nm and 2004 nm were employed to target H2O and CO2 absorption lines, respectively. Allan analysis of variance indicated that detection limits of H2O and CO2 were 5.98 ppm and 0.68 ppm, respectively, at an average time of 0.1 s. The sensor performance was demonstrated by measuring CO2 and H2O flux emissions at Jiangdu Agricultural Monitoring Station in Jiangsu Province. The results were compared with those obtained using the commercial instrument LI-7500, which is based on non-dispersive infrared technology. The developed gas analysis instrument exhibited good consistency with commercial instruments, and its accuracy was comparable; thus, it has strong application prospects for flux measurements in any ecosystem.
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Feng S, Qiu X, Guo G, Zhang E, He Q, He X, Ma W, Fittschen C, Li C. Palm-Sized Laser Spectrometer with High Robustness and Sensitivity for Trace Gas Detection Using a Novel Double-Layer Toroidal Cell. Anal Chem 2021; 93:4552-4558. [PMID: 33660979 DOI: 10.1021/acs.analchem.0c04995] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A palm-sized laser spectrometer has been developed for detecting trace gases based on tunable diode laser absorption spectroscopy in combination with a novel double-layer toroidal cell. With the benefit of a homemade electronic system and compact optical design, the physical dimensions of the sensor are minimized to 24 × 15× 16 cm3. A toroidal absorption cell, with 84 reflections in 2 layers for an effective optical path length of 8.35 m, was used to enhance the absorption signals of gaseous species. A homemade electronic system was designed for implementing a distributed feedback (DFB) diode laser controller, an analog lock-in amplifier, data acquisition, and communication. Calibration-free scanned wavelength modulation spectroscopy was employed to determine the concentration of the gas and reduce the random fluctuations from electronical noise and mechanical vibration. The measurement of CH4 in ambient air was demonstrated using a DFB laser at 1.653 μm. The rise time and fall time for renewing the gas mixture are approximately 16 and 14 s, respectively. Vibration and temperature tests have been carried out for verifying the performance of the spectrometer, and standard deviations of 0.38 ppm and 0.11 ppm for 20 ppm CH4 at different vibration frequencies and temperatures, respectively, have been determined. According to the Allan deviation analysis, the minimum detection limit for CH4 can reach 22 ppb at an integration time of 57.8 s. The continuous measurement of atmospheric CH4 for 2 days validated the feasibility and robustness of our laser spectrometer, providing a promising laser spectral sensor for deploying in unmanned aerial vehicles or mobile robots.
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Affiliation(s)
- Shiling Feng
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Xuanbing Qiu
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Guqing Guo
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Enhua Zhang
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Qiusheng He
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Xiaohu He
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Weiguang Ma
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006, China
| | - Christa Fittschen
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, Lille F-59000, France
| | - Chuanliang Li
- College of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China
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Gao G, Zhang T, Zhang G, Liu X, Cai T. Simultaneous and interference-free measurements of temperature and C 2H 4 concentration using a single tunable diode laser at 1.62 µm. OPTICS EXPRESS 2019; 27:17887-17904. [PMID: 31252741 DOI: 10.1364/oe.27.017887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/31/2019] [Indexed: 06/09/2023]
Abstract
In the tunable diode laser absorption spectroscopy-based diagnostics, the absorption of the measured target species may be influenced by the interference absorption from other vapor-phase species and the extinction from particles and liquid droplets, especially at high temperatures and pressures. Here, we report the first application (to our knowledge) of a differential absorption diagnostic for interference-free, simultaneous measurement of temperature and ethylene concentration using a single distributed-feedback diode laser near 1.62 μm. According to the detailed study of the C2H4 spectra in this region, two wavelength pairs are chosen to measure the temperature based on six selection criteria. C2H4 concentration is measured by one of the selected wavelength pairs with higher differential absorption. To validate the developed system, experiments are performed in a well-controlled heated static cell at a range of temperatures (300-900 K) and pressures (1-6 atm). The measurement accuracies for temperature and ethylene concentration are 1.83% and 1.65%, respectively, over the considered ranges. The precision, stability, and detection limit are also analyzed to validate the system's performance. This system can potentially be applied in a variety of combustion applications.
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