Results 41 to 50 of about 1,607 (170)

Side-polished fiber evanescent wave quartz-enhanced photoacoustic spectroscopy employing dielectric coatings for evanescent field enhancement. [PDF]

open access: yesPhotoacoustics
We report an all-fiber laser gas analyzer (LGA) based on quartz-enhanced photoacoustic spectroscopy (QEPAS) that exploits strong evanescent wave (EW) enhancement using a dielectric coating on side-polished fiber.
Twomey CF   +6 more
europepmc   +2 more sources

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

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

Cantilever-Enhanced Photoacoustic Spectroscopy of Radioactive Methane [PDF]

open access: yes, 2020
We report the first high-resolution spectroscopy study of radiocarbon methane, 14CH4. Several absorption lines of the fundamental vibrational band n3 were measured using a continuous-wave mid-infrared optical parametric oscillator with cantilever ...
Lauri Halonen   +23 more
core   +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

Photothermal detection of trace compounds in water, using the deflection of a water meniscus [PDF]

open access: yes, 1998
Anovelphotothermaldetectorisdescribed,basedonaclosedcellsuitableforusewithlow-frequencymodulatedcontinuous-wavelightsources.Photothermalexpansioninaqueoussamplescausedthedeflectionofawatermeniscusheldacrossa200m-radiuspinhole ...
Johnson, Mark   +2 more
core   +1 more source

Dual-frequency modulated heterodyne quartz-enhanced photoacoustic spectroscopy

open access: yesOptics Express, 2023
A novel dual-frequency modulated heterodyne quartz-enhanced photoacoustic spectroscopy (DFH-QEPAS) was demonstrated for what we believe to be the first time in this study. In traditional H-QEPAS, the frequency of modulated sinusoidal wave has a frequency difference (Δf) with the resonance frequency (f0) of a quartz tuning fork (QTF).
Ziting Lang   +5 more
openaire   +2 more sources

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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