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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Spectroscopic characterization at THz frequencies of glucose-based biomaterials: paramylon, paramylon-ester and cellulose
摘要： The terahertz (THz) spectroscopy of paramylon (β-1,3-glucan) and paramylon-ester extracted from microalgae called as Euglena have been studied by Fourier Transform Infrared Spectrometer (FT-IR) in a frequency range from 0.3 to 9 THz. The absorption spectra of paramylon were analyzed by comparing them with cellulose that has a similar long-chain -(C6H10O5)n-structure with paramylon. The differences in absorption features between paramylon and cellulose may be caused by their different chain structures. The broad absorption spectra of paramylon-ester can be attributed to some sort of disorder of long-chain molecular vibration modes due to the substitution of propionyl chloride and long-chain acid chloride by esterification.
关键词： microalgae,Euglena,paramylon-ester,paramylon,cellulose,terahertz spectroscopy,Fourier Transform Infrared Spectrometer
更新于2025-09-11 14:15:04
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Methods of improving spatial resolution for IR spectroscopy in atmospheric-pressure plasma systems
摘要： High-temperature, atmospheric pressure plasma systems operated in molecular gases present complex diagnostic challenges. Infrared spectroscopy has been used to make measurements of the absorbance spectrum of complex molecular gas mixtures and thereby calculate the concentrations and species temperatures in these systems. For atmospheric-pressure systems, high spatial gradients arise and high spatial-resolution measurements are thus desirable. Some systems have achieved increased spatial resolution by reducing the beam diameter. However, this increase in spatial resolution comes at the expense of the optical throughput. Here we propose modifying a commercial Fourier Transform, Infrared spectrometer system with a set of simple optical elements. This design allows for scannable, high spatial resolution absorbance spectrum measurements of a complex molecular gas mix. We analyze the signal-to-noise ratio for this design and compare it with the diameter reduction method. For sufficiently low plasma radiation levels, this design improves the signal-to-noise ratio relative to reducing the beam diameter size while transmitting nearly all of the beam power. However, whether this design can achieve the desired sub-mm spatial resolution depends on the radiating area of the infrared light source in the spectrometer.
关键词： Fourier Transform Infrared spectrometer,IR spectroscopy,spatial resolution,atmospheric-pressure plasma systems,signal-to-noise ratio
更新于2025-09-04 15:30:14
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On-Line Analysis of Oil-Dissolved Gas in Power Transformers Using Fourier Transform Infrared Spectrometry
摘要： To address the problem of on-line dissolved gas analysis (DGA) of a power transformer, a Fourier transform infrared (FT-IR) spectrometer was used to develop an analysis instrument. Carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), ethane (C2H6), ethylene (C2H4) and acetylene (C2H2) were the analytes for the FT-IR spectrometer while propane (C3H8), propylene (C3H6), propyne (C3H4), n-butane (n-C4H10) and iso-butane (iso-C4H10) were the interferents, which might exist in the dissolved gas but are not currently used as analytes for detecting an internal fault. The instrument parameters and analysis approach are first introduced. Specifically, an absorption spectra reading approach by switching two cone-type gas cells into separate light-paths was presented for reducing the effects of gas in the gaps between gas cells and spectrometers, scanning the background spectrum without clearing the sample cell, and increasing the dynamics. Then, the instrument was tested with a standard gas mixture that was extracted from insulation oil in a power transformer. The testing results show that the detection limit of every analyte component is lower than 0.1 μL/L, and the detection limits of all analytes meet the detection requirements of oil-dissolved gas analysis, which means that the FT-IR spectrometer may be an ideal instrument due to its benefits, such as being maintenance-free and having a high stability.
关键词： power transformer,oil-dissolved gas,gas chromatograph,spectral analysis,Fourier transform infrared spectrometer
更新于2025-09-04 15:30:14