Results 41 to 50 of about 909 (177)

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

Optics
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, Jiahui Wu, Haoyang Lin, Lihao Wang, Jianfeng He, Leqing Lin, Ruobin Zhuang, Guantian Hong, Jiabao Xie, Jianhui Yu, Wenguo Zhu, Yongchun Zhong, Zhigang Song, Huadan Zheng   +13 more
doaj   +2 more sources

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

Photoacoustics, 2022
In this paper, a highly sensitive and integrated near-infrared CO2 sensor was developed based on quartz-enhanced photoacoustic spectroscopy (QEPAS).
Yihua Liu, Haoyang Lin, Baiyang Antonio Zhou Montano, Wenguo Zhu, Yongchun Zhong, Ruifeng Kan, Bin Yuan, Jianhui Yu, Min Shao, Huadan Zheng   +9 more
doaj   +1 more source

LED-Absorption-QEPAS Sensor for Biogas Plants [PDF]

Sensors, 2015
A new sensor for methane and carbon dioxide concentration measurements in biogas plants is presented. LEDs in the mid infrared spectral region are implemented as low cost light source. The combination of quartz-enhanced photoacoustic spectroscopy with an absorption path leads to a sensor setup suitable for the harsh application environment.
Köhring, Michael, Böttger, Stefan, Willer, Ulrike, Schade, Wolfgang   +3 more
openaire   +6 more sources

Parts-per-billion detection of carbon monoxide: A comparison between quartz-enhanced photoacoustic and photothermal spectroscopy

Photoacoustics, 2021
We report on a comparison between two optical detection techniques, one based on a Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS) detection module, where a quartz tuning fork is acoustically coupled with a pair of millimeter-sized resonator tubes ...
Davide Pinto, Harald Moser, Johannes P. Waclawek, Stefano Dello Russo, Pietro Patimisco, Vincenzo Spagnolo, Bernhard Lendl   +6 more
doaj   +1 more source

Broadband QEPAS with IR-LEDs

, 2022
S.2236-2237An IR-LED at 3.4 mum and an off-beam QEPAS cell as detector are utilized for absorption spectroscopy.
Schade, W., Böttger, S., Willer, U.
core   +3 more sources

GaSb Halbleiterlaser im Wellenlängenbereich 1, 9 µm - 2, 2 µm, deren Anwendungen in der QEPAS sowie deren Miniaturisierung [PDF]

, 2021
Die Messung von Spurengasen ist für viele Bereiche essentiell. So werden beispielsweise industrielle Verfahren anhand der Konzentration von Prozessgasen gesteuert oder ärztliche Diagnosen durch den Befund von Spurengasen im menschlichen Atem gefällt.
Milde, Tobias
core   +1 more source

Anomalous Humidity Dependence in Photoacoustic Spectroscopy of CO Explained by Kinetic Cooling

Applied Sciences, 2020
Water affects the amplitude of photoacoustic signals from many gas phase molecules. In quartz-enhanced photoacoustic (QEPAS) measurements of CO excited at the fundamental vibrational resonance of CO, the photoacoustic signal decreases with increasing ...
Jakob Hayden, Bettina Baumgartner, Bernhard Lendl   +2 more
doaj   +1 more source

Phase Optimized Photoacoustic Sensing of Gas Mixtures

Applied Sciences, 2020
In this paper, we report on the progress of the auto-triggered quartz-enhanced photoacoustic spectroscopy (QEPAS) technique which operates without external frequency generators and ensures permanent locking to the current resonance frequency of the ...
Mario Mordmueller, Simon Edelmann, Markus Knestel, Wolfgang Schade, Ulrike Willer   +4 more
doaj   +1 more source

Environmental Monitoring of Methane with Quartz-Enhanced Photoacoustic Spectroscopy Exploiting an Electronic Hygrometer to Compensate the H₂O Influence on the Sensor Signal

Sensors, 2020
A dual-gas sensor based on the combination of a quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor and an electronic hygrometer was realized for the simultaneous detection of methane (CH4) and water vapor (H2O) in air. The QEPAS sensor employed an
Arianna Elefante, Giansergio Menduni, Hubert Rossmadl, Verena Mackowiak, Marilena Giglio, Angelo Sampaolo, Pietro Patimisco, Vittorio M. N. Passaro, Vincenzo Spagnolo   +8 more
doaj   +1 more source

A Miniaturized 3D-Printed Quartz-Enhanced Photoacoustic Spectroscopy Sensor for Methane Detection with a High-Power Diode Laser

Sensors, 2023
In this invited paper, a highly sensitive methane (CH4) trace gas sensor based on quartz-enhanced photoacoustic spectroscopy (QEPAS) technique using a high-power diode laser and a miniaturized 3D-printed acoustic detection unit (ADU) is demonstrated for ...
Yanjun Chen, Tiantian Liang, Shunda Qiao, Yufei Ma   +3 more
doaj   +1 more source