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Updated: Jun 22, 2025

Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere
Published on: April 30, 2018
Water rotational relaxation time measurement by shortwave infrared micro spectroscopy(SWIR) at sub-zero temperatures
1Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Japan.
Abstract:
The shortwave infrared spectroscopy (SWIR) is the noble method which allows to evaluate the rotational relaxation time of water (RRTW) in a sample. Because SWIR requires the reference sample of pure water, the measurement temperature is limited only at above 0 °C. In this study, we expanded this temperature limitation of SWIR by using alternative reference solutions with freezing points below 0 °C, including sugar and glycerol solutions. The results showed that some reference sample solutions are useable for evaluating RRTW in samples below 0 °C. It was found that RRTW in solution measured by newly proposed SWIR agrees with RRTW measured by dielectric spectroscopy in 10% accuracy when it is shorter than 100psec.
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