Results 21 to 30 of about 218 (120)

Integrated near-infrared QEPAS sensor based on a 28 kHz quartz tuning fork for online monitoring of CO2 in the greenhouse

open access: yesPhotoacoustics, 2022
In this paper, a highly sensitive and integrated near-infrared CO2 sensor was developed based on quartz-enhanced photoacoustic spectroscopy (QEPAS).
Yihua Liu   +9 more
doaj   +1 more source

Simultaneous Detection of Gas Concentration and Light Intensity Based on Dual-Quartz-Enhanced Photoacoustic-Photothermal Spectroscopy

open access: yesPhotonics, 2023
This research proposes a method for the simultaneous acquisition of the second harmonic (2f) signal of quartz-enhanced photoacoustic spectroscopy (QEPAS) and the first harmonic (1f) signal of quartz-enhanced photothermal spectroscopy (QEPTS) based on the
Hao Liu   +5 more
doaj   +1 more source

Detection of Molecular Oxygen at Low Concentrations Using Quartz Enhanced Photoacoustic Spectroscopy

open access: yesSensors, 2010
Molecular oxygen is detected at low concentrations using photoacoustic spectroscopy despite its unfavorable photoacoustic properties. The system consists of a seed laser diode, a tapered amplifier and a quartz tuning fork based spectrophone, thus ...
Andreas Pohlkötter   +3 more
doaj   +1 more source

Spider Silk-Improved Quartz-Enhanced Conductance Spectroscopy for Medical Mask Humidity Sensing

open access: yesMolecules, 2022
Spider silk is one of the hottest biomaterials researched currently, due to its excellent mechanical properties. This work reports a novel humidity sensing platform based on a spider silk-modified quartz tuning fork (SSM-QTF). Since spider silk is a kind
Leqing Lin   +11 more
doaj   +1 more source

Photoacoustic Techniques for Trace Gas Sensing Based on Semiconductor Laser Sources

open access: yesSensors, 2009
The paper provides an overview on the use of photoacoustic sensors based on semiconductor laser sources for the detection of trace gases. We review the results obtained using standard, differential and quartz enhanced photoacoustic techniques.
Vincenzo Spagnolo   +3 more
doaj   +1 more source

Benzene sensing by Quartz Enhanced Photoacoustic Spectroscopy at 14.85 µm

open access: yesOptics Express, 2022
Benzene is a gas known to be highly pollutant for the environment, for the water and cancerogenic for humans. In this paper, we present a sensor based on Quartz Enhanced Photoacoustic Spectroscopy dedicated to benzene analysis. Exploiting the infrared emission of a 14.85 µm quantum cascade laser, the sensor is working in an off-beam configuration ...
Diba Ayache   +7 more
openaire   +2 more sources

Quartz-enhanced photoacoustic spectroscopy employing pilot line manufactured custom tuning forks

open access: yesPhotoacoustics, 2020
Pilot line manufactured custom quartz tuning forks (QTFs) with a resonance frequency of 28 kHz and a Q value of >30, 000 in a vacuum and ∼ 7500 in the air, were designed and produced for trace gas sensing based on quartz enhanced photoacoustic ...
Huadan Zheng   +19 more
doaj   +1 more source

1D U-Net Enhanced QEPAS Sensor for Trace Water Vapor Detection

open access: yesOptics
We report a deep learning-assisted quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for trace water vapor detection in air. A 1392 nm butterfly-packaged DFB laser is wavelength-modulated at f0/2, and the QEPAS signal is retrieved by second ...
Huiming Xiao   +13 more
doaj   +1 more source

Review of Recent Advances in QEPAS-Based Trace Gas Sensing

open access: yesApplied Sciences, 2018
Quartz-enhanced photoacoustic spectroscopy (QEPAS) is an improvement of the conventional microphone-based photoacoustic spectroscopy. In the QEPAS technique, a commercially available millimeter-sized piezoelectric element quartz tuning fork (QTF) is used
Yufei Ma
doaj   +1 more source

Highly Sensitive Capacitive MEMS for Photoacoustic Gas Trace Detection

open access: yesSensors, 2023
An enhanced MEMS capacitive sensor is developed for photoacoustic gas detection. This work attempts to address the lack of the literature regarding integrated and compact silicon-based photoacoustic gas sensors. The proposed mechanical resonator combines
Tarek Seoudi   +7 more
doaj   +1 more source

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