Mikio Fukuhara 교수

Elastic (Young, shear and bulk moduli, Poisson's ratio and Lamé parameter), longitudinal and transverse internal friction values for low carbon steel and stainless steel were simultaneously measured over a temperature range 300-1500 K, by an ultrasonic pulse sing-around method. These elastic moduli decrease and Poisson's ratio increases with increasing temperature, suggesting activation of shear mode in a high temperature region. Longitudinal and transverse internal frictions are sensitive to re

Longitudinal and transverse wave velocities, six kinds of elastic parameters (Young, shear and bulk moduli, Lamè parameter, Poisson's ratio and acoustic wave velocity anisotropy factor) and dilational and shear internal frictions of a fused quartz have been simultaneously measured over a temperature range 298–1674 K, by an ultrasonic pulse sing-around method. These elastic moduli, Lamè parameter and Poisson's ratio increase with increasing temperature, suggesting enhancement of rigidity for mixe

Longitudinal and transverse wave velocities, six kinds of elastic parameters, and dilational and shear internal frictions have been simultaneously measured as functions of temperature between room temperature and 77 K in the high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{GdBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\delta}}}$. An abrupt increase from 117 K in bulk modulus and Lam\`e parameter suggests that the order parameter has a much stro

The acoustic characteristics of sound fresh tea leaves were determined nondestructively by ultrasonic transmission analysis. As thickness increases, phase velocity and wavelength increase, and damping ratio and dynamic viscosity decrease, suggesting development of the fibrous tissues, accompanied by frequency convergence. The velocities of all the leaves studied were smaller than that of pure water. Decrease in viscoelasticity corresponds to increase in dynamic modulus. Thus, acoustically, we ca

Despite the intense interest in cellulose nanofibers (CNFs) for biomedical and engineering applications, no research findings about the electrical energy storage of CNF have been reported yet. Here, we present the first electroadsorption effects of an amorphous cellulose nanofiber (ACF) supercapacitor, which can store a large amount of electricity (221 mJm^-2, 13.1 Wkg^-1). The electric storage can be attributed to the entirely enhanced electroadsorption owing to a quantum-si

The effect of Al 2 O 3 and (Ti or Si)C additions on various properties of a (Y)TZP (yttria‐stabilized tetragonal zirconia polycrystal)–Al 2 O 3 –(Ti or Si)C ternary composite ceramic were investigated for developing a zirconia‐based ceramic stronger than SiC at high temperatures. Adding Al 2 O 3 to (Y)TZP improved transverse rupture strength and hardness but decreased fracture toughness. This binary composite ceramic revealed a rapid loss of strength with increasing temperature. Adding TiC to th

Using ultrasonics, TiNi's acoustic characteristics are observed in order to fully understand its memory effects. Longitudinal and transverse wave velocities, eight kinds of elastic parameters, and dilational and shear internal frictions are simultaneously measured as functions of temperature in cooling and heating runs between 223 and 374 K in TiNi alloy, using an ultrasonic pulse method. An abrupt decrease from around 300 K in Young and shear moduli, Debye temperatures and internal friction pea