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Furusawa, Akinori; Takenaka, Yusuke; Nishimura, Akihiko
Applied Sciences (Internet), 9(17), p.3544_1 - 3544_12, 2019/09
Times Cited Count：9 Percentile：60.45(Chemistry, Multidisciplinary)Remote-controlled, non-destructive testing is necessary to detect corrosion of the reinforced concrete structures at the Fukushima Daiichi Nuclear Power Plant (NPP) de-commissioning site. This work aims to demonstrate that laser-induced ultrasonic guided wave technology can be applied to achieve this task. Hence, accelerated electrolytic corrosion is performed on a reinforced concrete specimen fabricated by embedding a steel rod into mortar. Waveforms of the laser-induced ultrasonic guided wave on the rod are measured with a previously employed piezoelectric transducer (PZT) probe, for each fixed corrosion time. Based on the results of Fourier and wavelet transforms of the waveforms, issues concerning the detection and extent of rebar corrosion are discussed. It is exhibited that the changes in bonding strength due to corrosion are distinguishable in the frequency domain of the ultrasonic signal.
nanoparticles by pulsed laser ablation; Ambient pressure dependence of crystallizationMatsubara, Masakazu*; Yamaki, Tetsuya; Ito, Hisayoshi; Abe, Hiroaki*; Asai, Keisuke*
Japanese Journal of Applied Physics, Part 2, 42(5A), p.L479 - L481, 2003/05
Pulsed laser ablation with a KrF excimer laser was used to prepare fine particles of titanium dioxide (TiO). The ablation in an atmosphere of Ar and O (5:5) at total pressures of 
1 Torr led to the formation of TiO nanoparticles composed of anatase and rutile structures without any suboxides. The weight fraction of the rutile/anatase crystalline phases was controlled by the pressure of the Ar/O gas. The TiO nanoparticles had a spherical shape and their size, ranging from 10 and 14 nm, also appeared to be dependent on the ambient pressure.
