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A gas analyzer has been developed using cavity ring‐down spectroscopy (CRDS) technology, designed to simultaneously measure the concentrations of CO2 and CO. These gases are critical indicators of transformer insulation degradation. The analyzer covers a CO2 concentration range from a few ppm to several thousand ppm and can measure CO/CO2 concentration ratios from 0.076 to 0.8. The selected absorption lines for CO and CO2 are centered at 6337.99 and 6338.59 cm−1, respectively. The two candidate lines are proximate to each other and nonoverlapping. The experimental results indicate that the system accurately fits the measured and calculated signals, enabling concentration measurements at the ppm level. This confirms its ability to measure the gas concentrations and ratios critical for assessing the condition of transformer insulation. This CRDS‐based system offers a reliable and sensitive method for early detection of potential transformer faults. [ABSTRACT FROM AUTHOR]

Flour is an essential ingredient in human daily diet, thus it is crucial to measure its moisture content. However, current detection methods are time‐consuming and labor‐intensive, hindering quick measurement. Here we demonstrate the measurement of moisture content in flour via gas in the scattering media absorption spectroscopy (GASMAS) technique. A compact sensor that includes distributed feedback laser driver, cuvette, photodetector, analog lock‐in amplifier, and analysis processing module is developed. We measure the equivalent mean path length of various flour samples, and verify the measurement sensitivity of GASMAS by studying its dependence on moisture content. A linear relationship between path length and moisture content is established by least‐squares curve fitting, corresponding to a correlation coefficient of 0.996. Compared to the drying method, our method shows a maximum error range of 6.1% for all samples, providing a highly accurate and reliable measurement of water content in flour. [ABSTRACT FROM AUTHOR]

The temperature measurement of Sulfur dioxide (SO2) is a crucial parameter for accurately determining its concentration, particularly in high‐temperature environment. Herein, it is realized by using three different techniques, which are direct absorption spectroscopy, wavelength modulation spectroscopy and non‐calibration wavelength modulation spectroscopy based on the bispectral lines temperature measurement method. The bispectral lines of SO2 locates at 1396.844 and 1396.921 cm−1, respectively. The gas temperature in the absorption cell was also measured with K‐type thermocouple and compared with these three spectral measurements. The linearities corresponding to these three techniques are 99.71%, 99.8%, and 99.88%, respectively. Their average relative error between the spectral measurement results and the linear fitting value of the three techniques is 1.15%, 0.86%, and 0.57%, respectively. It is illustrated the feasibility of the bispectral lines method for high‐temperature measurement. These investigations provide methods for temperature measurement in high‐temperature coal‐fired boilers, potentially for investigating other sulfide gas molecules such as SO3 and H2S. [ABSTRACT FROM AUTHOR]