Sensors and Actuators B Chemical, Journal Year: 2025, Volume and Issue: unknown, P. 137918 - 137918
Published: May 1, 2025
Language: Английский
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(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
Analytical Chemistry, Journal Year: 2025, Volume and Issue: unknown
Published: March 29, 2025
Carbon disulfide (CS2) and sulfur dioxide (SO2) are typical indicative gases for the early warning diagnosis of faults in gas-insulated switchgear. In this study, an optical sensing system is reported online detection CS2 SO2 based on a bidirectional self-correction technology (BSCT). First, differential absorption signals wavelength range 195-230 nm obtained using UV spectroscopy (UV-DOAS) technique. On basis, BSCT proposed to decouple spectral lines that exhibit significant overlap. This method primarily employs difference mutually correct spectra SO2, combined with reconstruction extract single-component from mixed gas spectra. Furthermore, effectiveness novel decoupling technique validated by comparing results standard at corresponding concentrations. Finally, quantitative relationships between concentrations target (CS2, SO2) parameters modeled least-squares method. The experimental show mean absolute percentage errors (19.00-3735.35 ppb) (0.19-38.77 ppm) 0.543 0.521%, respectively. At effective 50 cm, achieves lowest limits 0.5 ppb 12 representing best date ppb-ppm range.
Language: Английский
Citations
0
Microwave and Optical Technology Letters, Journal Year: 2025, Volume and Issue: 67(4)
Published: March 28, 2025
ABSTRACT Carbon dioxide (CO 2 ) is a major greenhouse gas contributing to climate change. Especially, the real‐time monitoring of its spatial and temporal variations have drawn significant attention in past few decades. In present work, we proposed Differential Absorption LiDAR (DIAL) system for CO concentration profiling. By employing dual‐wavelength 1.5 μm fiber laser an InGaAs/InP negative feedback avalanche diode (NFAD) based free‐running single‐photon detector (SPD), it allowed be compact, with low power consumptions. Comparisons between different pulse durations, energies peak powers were performed terms signal‐to‐noise ratio ( SNR backscattering signals LiDAR. It shown that three parameters combined effect on signal response behavior. After optimization energy, integration time, workflow profile retrieval, analytical performance has been evaluated. The evolution measured nicely coincides values from standard detector, correlation coefficient higher than 0.7 relative deviation within 6.8%. Subsequently, vertical observations carried out obtain height‐time plot concentrations, high spatial‐temporal resolution 25 m 15 min, respectively. results indicated diurnal variation at nearshore region. This compact DIAL shows promising potential streamlining online atmospheric over ocean buoy platforms.
Language: Английский
Citations
0
Sensors and Actuators B Chemical, Journal Year: 2025, Volume and Issue: unknown, P. 137699 - 137699
Published: April 1, 2025
Language: Английский
Citations
0
Sensors and Actuators B Chemical, Journal Year: 2025, Volume and Issue: unknown, P. 137713 - 137713
Published: April 1, 2025
Language: Английский
Citations
0
Microwave and Optical Technology Letters, Journal Year: 2025, Volume and Issue: 67(4)
Published: April 1, 2025
ABSTRACT Due to the influence of automobile exhaust in underground parking lots all year round, a large amount carbon monoxide (CO) gas accumulates lots, endangering safety human lives. Based on tunable diode laser absorption spectroscopy (TDLAS) technology, CO detection system is designed be applied lots. A distributed feedback baser (DFB) was used scan peak at 1.566 μm, avoiding interference from other background gases. small multi‐pass cell (MPGC) with volume only 704 cm 3 and an effective optical range up 26 m. An improved wavelet thresholding denoising‐complete esemble empirical mode decomposition adaptive noise (IWTD‐CEEMDAN) denoising algorithm filter out effects noise, thereby improving signal‐to‐noise ratio (SNR) lowering limit system. greater cane rat algorithm‐bidirectional long short‐term memory (GCRA‐BiLSTM) concentration inversion improve accuracy inversion. According Allan variance, (LoD) sensor 11.57 ppm 1 s 0.124 117 s. series experiments are carried sensor, experimental results show that has good linearity, stability, LoD, which can realize real‐time monitoring garage CO, it important application value.
Language: Английский
Citations
0
Applied Physics Letters, Journal Year: 2025, Volume and Issue: 126(17)
Published: April 28, 2025
A single fiber-optic photoacoustic sensor (FOPAS) is applied for the simultaneous detection of SF6 purity and decomposition derivative H2S, measurement results are corrected based on purity. H2S gas concentration identified by tracking frequency detecting signal 1f 2f, respectively. The influence resonance frequency, excitation intensity, cantilever response theoretically derived, simulated, experimentally verified. In range 80%–100%, there a linear relationship between purity, with 1.923 Hz/% minimum change limit 0.02%.The FOPAS designed T-type cell achieves 5 ppb normalized noise equivalent absorption coefficient reaches 4 × 10−10 cm−1 Hz−1/2 W. Taking 97% as an example, evaluated both before after correction. By correcting signal, accuracy improved 9%. adopting overall analysis method, high-precision high-sensitivity monitoring dual-state parameters has been achieved, providing technical support accurate early warning latent faults in gas-insulation equipment.
Language: Английский
Citations
0
Sensors and Actuators B Chemical, Journal Year: 2025, Volume and Issue: unknown, P. 137918 - 137918
Published: May 1, 2025
Language: Английский
Citations
0