Performance enhancement of DFBL based near‐infrared CH 4 telemetry system using a focus tunable lens

Self Cite

Carbon dioxide (CO 2 ) gas is one of the main greenhouse gases. The detection of CO 2 gas content is of great significance to the study of the greenhouse effect. The CO 2 detection system based on the principle of tunable diode laser absorption spectroscopy (TDLAS) was demonstrated. A distributed feedback (DFB) laser with a central wavelength of 1580 nm was used as the laser source, multipass gas cell (MPGC) was used as gas cell, and indium gallium arsenic (IGA) photodetector was used to complete photoelectric conversion, and the original extracted second harmonic signal was smooth and denoised by wavelet transform. The signal-to-noise ratio (SNR) of the wavelet-filtered spectrum improved from 6.88 to 13.87 dB, an improvement of 2.02 times. Principal component analysis was used to reduce the complexity of the data by compressing the spectrum from 800 dimensions to 2 dimensions. For the concentration inversion, the back-propagation deep neural network (BP-DNN) model was used to perform standard gas concentration step experiments and compared with the back-propagation neural network (BPNN). The experimental results show that the BP-DNN inversion of CO 2 concentration has improved computational accuracy and the root mean square error (RMSE) is 3.55 times lower than that of the traditional BPNN, showing favorable application prospects.

Section: Introductionmentioning

confidence: 99%

A near‐infrared CO₂ detection system for greenhouse gas based on PCA‐DNN

Liu

et al. 2022

Self Cite

“…In the past few years, the use of wavelength modulated absorption spectroscopy (WMAS) technology to monitor the growth of microorganisms has aroused considerable interest because of its characteristics including high sensitivity, high selectivity, high resolution, simple structure, and non‐invasiveness, which are indispensable to develop a fast online detection method 17–21 . Actually, it has been widely used in trace gas analysis, 22–24 chemical reaction process measurement, atmospheric environment monitoring, industrial combustion control, early disease diagnosis and screening, aeroengine stability test and many other application fields 25–28 . Several research groups have studied the utility of WMAS as a variety of fermentation process analysis techniques, such as Karla Martinez‐Cruz et al used WMS technology to estimate the capability of anaerobic biomass to treat effluents, 29 David Brueckner et al used WMS technology to evaluated on its potential to detect bacterial growth of contaminated media fill vials, 30 Anna Solokhina et al used WMS technology to measure the effect of isoniazid on metabolic activity and respiratory capability of mature Mycobacterium tuberculosis H37Ra (an avirulent strain) and Mycobacterium smegmatis biofilms 31 .…”

Section: Introductionmentioning

confidence: 99%

Estimation of Staphylococcus aureus growth rates from CO₂ with absorption spectroscopy

Zhang

et al. 2022

It is very important to monitor and evaluate the growth of Staphylococcus aureus (S. aureus) under various conditions. However, so far there is no technology that can monitor S. aureus in real time. This work proves that the wavelength modulated absorption spectroscopy (WMAS) based on tunable diode lasers can quickly measure the concentration of carbon dioxide produced by microorganisms. We use a variety of fitting models to get the growth curves of S. aureus and calculated the relationship between the growth rate and time through the obtained growth curve. Using the proposed technology, we have studied the growth status of S. aureus at different temperatures (five points in the range of 26-43 C), and the results show that the maximum growth rate have a strong temperature dependence. Therefore, it is proved that WMAS monitoring S. aureus is a user-friendly, non-invasive, fast, and high signal-to-noise ratio technology, which can be used for rapid and accurate bacterial growth assessment in the industry.

“…Absorption spectroscopy is widely used in trace gas detection, among which tunable diode laser absorption spectroscopy (TDLAS) and quartz‐enhanced photoacoustic spectroscopy are widely used. TDLAS technology, as a direct absorption spectroscopy technology, has the advantages of clear system principle and simple structure, and is widely used in environmental monitoring, industrial process control, fire security, biological and medical research, and other fields of spectral detection 1–7 . However, in the harsh and complex environment in the field, the TDLAS system is required to improve its portability while ensuring high performance.…”

Section: Introductionmentioning

confidence: 99%

Investigation on small volume and long optical path multipass cell using differential evolution algorithm

Zhang

Chen

et al. 2022

To solve the contradiction between high performance and portability of tunable diode laser absorption spectroscopy (TDLAS) systems, we propose a multipass cell (MPC) design method based on differential evolution (DE) algorithm, and realize intelligent optimization design of MPC with small volume and long optical path. MPC is the core component of the TDLAS system. The optical path of MPC determines the detection accuracy of the TDLAS system. The optical path is affected by the position and angle of incident laser, mirror spacing, and other parameters. The DE algorithm is used to optimize the parameters that affect the performance of MPC, and a compact MPC with a spherical mirror diameter of 25.4 mm, a laser reflection number of 183, an optical path of 5.98 m, and a mirror spacing of 31.7 mm is designed. Under the same spherical mirror condition, the detection limit of MPC designed based on the DE algorithm is increased from 0.91 to 0.76 ppm compared with the MPC commonly used seven-ring spot pattern. This has a guiding and exemplary role in the design and development of high space utilization MPC.