20GHz-TDR装置を使った比誘電率測定の特徴 [in Japanese] On Measuring Dielectric Constant Using a 20GHz Time Domain Reflectometry Instrument [in Japanese]
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Nondestructive measurements of water content in porous media, e.g., bricks, stones, and compacted soil, are required to assess the deterioration of historical buildings/structures. Unlike conventional methods, time domain reflectometry (TDR) can nondestructively and continuously measure water content by monitoring changes in dielectric constant. The popularly-used TDR instrument, e.g., 1502C of Tektronix Inc., has an effective frequency range of 1GHz while a higher-end TDR instrument, e.g., 86100B+54754A of Agilent Technologies, has that of 20GHz. The 20GHz TDR instrument provided clearer waveforms with a 4cm-long probe than did the 1GHz TDR instrument when a TDR probe was placed in conditions with less water content. Further research is needed for an appropriate design of a TDR probe and for improving a waveform analysis algorithm.
- 保存科学 = Science for conservation
保存科学 = Science for conservation (44), 97-102, 2005-03-31