Sensors and Actuators B Chemical, Journal Year: 2025, Volume and Issue: unknown, P. 137918 - 137918
Published: May 1, 2025
Language: Английский
Photoacoustics, Journal Year: 2025, Volume and Issue: unknown, P. 100699 - 100699
Published: Feb. 1, 2025
Language: Английский
Citations
7
Analytical Chemistry, Journal Year: 2025, Volume and Issue: unknown
Published: Feb. 27, 2025
In this paper, an acetylene–carbon dioxide dual-component gas sensor based on light-induced thermoelastic spectroscopy and deep learning is reported for the first time. Two lasers with wavelengths of 1530 1577 nm were coupled by a wavelength division multiplexer to excite two molecules. The combined four algorithms, namely, sparrow search algorithm (SSA), convolutional neural network (CNN), bidirectional gated recurrent unit (BiGRU), attention mechanism (Attention), achieve two-component concentration inversion in three cases, which overlap spectral lines different. advantage combination SSA-CNN-BiGRU-Attention model that weight can be assigned according characteristics second harmonic (2f) signal itself, optimal parameters automatically found. effectively improved accuracy significantly reduced mean relative error (MRE). experimental results show R-square values test set are all greater than 0.99, MRE less 1.2%, showing high accuracy. This work provides instructions absorption line detection expected applied study more components future.
Language: Английский
Citations
4
Analytical Chemistry, Journal Year: 2025, Volume and Issue: unknown
Published: March 20, 2025
In the paper, quartz-enhanced photoacoustic spectroscopy (QEPAS) and heterodyne (H-QEPAS)-based ppb-level methane (CH4) detection using a self-designed low-frequency round-head quartz tuning fork (QTF) power-amplified diode laser is reported for first time. Compared to standard 32.768 kHz QTF, novel with resonance frequency (f0) of 9.7 kHz, utilized as acoustic wave transducer, benefiting from longer energy accumulation time reduced optical noise. A Raman fiber amplifier (RFA) adopted amplify power continuous wavelength distributed feedback (CW-DFB) 300 mW. Acoustic microresonators (AmRs) at specific sizes are on both sides QTF enhancement waves. It observed that, after installation AmRs, signal level enhanced by factor 107.029 compared bare QTF. Both CH4-QEPAS CH4-H-QEPAS sensors show excellent linearity in response CH4 concentration, R-squared values exceeding 0.99 each. The minimum limit (MDL) determined be 1.321 2.126 ppb CH4-H-QEPAS, respectively, when integration sensor systems extended 1000 s. 50 s measurement period sensor, can identify f0 finish 3 s, demonstrating its rapid capability. Furthermore, H-QEPAS technology allows acquisition without interrupting measurement, enabling real-time calibration f0. Finally, monitoring concentrations air human-exhaled gases, practical capabilities.
Language: Английский
Citations
1
Sensors, Journal Year: 2025, Volume and Issue: 25(3), P. 840 - 840
Published: Jan. 30, 2025
Based on tunable diode laser absorption spectroscopy (TDLAS), a water isotopes detection system was developed to detect the isotopic abundance of vapor in atmosphere. A single 1483.79 cm−1 quantum cascade (QCL) and 3120 cm optical path multi-pass cell (MPC) were adopted system. The selected spectral range, as well technology used, is particularly interesting for real-time monitoring In this study, can be used perform high-sensitivity, rapid investigations H2O, H218O, H217O, HDO lines. Finally, we measured values three atmosphere compared them with data from Global Network Isotopes Precipitation (GNIP) website, dedicated exploring possibility situ H₂O
Language: Английский
Citations
0
Photoacoustics, Journal Year: 2025, Volume and Issue: 42, P. 100692 - 100692
Published: Feb. 1, 2025
An innovative and miniature photoacoustic spectroscopy (PAS) gas sensor based on a multivariate-coupled amplification cell (MVCA-PAC) with total length of 100 mm was developed to achieve ultra-sensitive trace CH4 detection. Acoustic pressure distribution simulations reveal that at the first-order resonance frequency, MVCA-PAC achieves maximum acoustic approximately 3.9 times higher than conventional cell. The absorption optical path reached 2068 through 22 reflections, resulting in 2-fold increase amplitude signals compared traditional an equivalent path. Furthermore, single-pass cell, 2-f signal intensity increased by factor 4.5. Allan variance analysis indicated detection limit 0.572 ppm for averaging time 300 s. To further improve measurement precision designed sensor, Chebyshev rational fractional-order filtering (CRFOF) algorithm introduced PAS processing first time. Post-processing results demonstrated 15.4-fold improvement precision, achieving 0.578 ppm. Finally, continuous monitoring atmospheric over 48-hour period validated reliability feasibility sensor.
Language: Английский
Citations
0
Sensors, Journal Year: 2025, Volume and Issue: 25(3), P. 946 - 946
Published: Feb. 5, 2025
A highly sensitive light-induced thermoelastic spectroscopy (LITES) sensor employing a charge amplifier (CA) is reported for the first time in this invited paper. CA has merits of high input impedance and strong anti-interference ability. The usually used transimpedance (TA) voltage (VA) were also studied under same conditions comparison. standard commercial quartz tuning fork (QTF) with resonant frequency approximately 32.76 kHz was as photothermal signal transducer. Methane (CH4) target gas these sensors performance verification. Compared to TA-LITES VA-LITES sensor, CA-LITES shows improvements 1.83 times 5.28 minimum detection limit (MDL), respectively. When compared LITES without an (WA-LITES), MDL 19.96-fold improvement. After further optimizing gain CA, calculated 2.42 ppm, which improved by 30.3 WA-LITES. Additionally, long-term stability analyzed using Allan deviation analysis. average system increased 50 s, can be 0.58 ppm.
Language: Английский
Citations
0
Photoacoustics, Journal Year: 2025, Volume and Issue: 42, P. 100702 - 100702
Published: Feb. 19, 2025
A ppb-level sulfur dioxide (SO2) monitoring platform was developed by exploiting standard photoacoustic spectroscopy and a novel, highly stable UV laser. 266.22 nm LD-pumped solid-state, acousto-optic modulator Q-switched laser with high beam quality (M2 =1.0275) excellent output optical power stability (δPσ ˂ 1 % ∼24 h) selected as light source of the sensor. The performance SO2 sensor evaluated in terms gas flow rate, pressure, detection sensitivity. An ultimate limit 3 ppb for N2 demonstrated s integration time, laboratory environment. Continuous outdoor five days verified reliability reported
Language: Английский
Citations
0
Photoacoustics, Journal Year: 2025, Volume and Issue: 43, P. 100708 - 100708
Published: Feb. 27, 2025
We present a novel optical synchronized signal demodulation (OSSD) method applied in quartz-enhanced photoacoustic spectroscopy (QEPAS) for remote gas sensing. Using 1 % of the laser source as an synchronization signal, kilometer-scale detection was achieved, overcoming challenges long-distance real-time complex environments with conventional QEPAS. A time-sharing OSSD-QEPAS system sewer methane subsequently developed. The system's modulation depth optimized, and catalytic effect water vapor on signals validated, resulting CH₄ sensor achieving limit 445 ppb 300-ms averaging time, excellent linear dynamic range R2 = 0.999. To demonstrate stability, robustness, accuracy system, continuous measurements covering 14-hour period at two different locations campus were performed.
Language: Английский
Citations
0
Photoacoustics, Journal Year: 2025, Volume and Issue: 43, P. 100707 - 100707
Published: Feb. 27, 2025
Language: Английский
Citations
0
Sensors, Journal Year: 2025, Volume and Issue: 25(7), P. 2099 - 2099
Published: March 27, 2025
A carbon dioxide (CO2) sensor based on light-induced thermoelastic spectroscopy (LITES) using a 2 μm diode laser and self-designed low-frequency trapezoidal-head QTF is reported for the first time in this invited paper. The with low resonant frequency of 9464.18 Hz high quality factor (Q) 12,133.56 can significantly increase accumulation signal level CO2-LITES sensor. continuous-wave (CW) distributed-feedback (DFB) used as light source, strongest absorption line CO2 located at 2004.01 nm chosen. comparison between standard commercial 32.768 kHz performed. experimental results show that has an excellent linear response to concentration, its minimum detection limit (MDL) reach 46.08 ppm (parts per million). When average increased 100 s Allan variance analysis, MDL be improved 3.59 ppm. Compared 16.85 QTF, performance by 4.7 times, demonstrating superiority QTF.
Language: Английский
Citations
0