Heki K.,Hokkaido University |
Enomoto Y.,Toyama Industrial Technology Center
Journal of Geophysical Research: Space Physics | Year: 2013
Possible enhancement of ionospheric Total Electron Content (TEC) immediately before the 2011 Tohoku-oki earthquake (Mw9.0) has been reported by Heki (2011). Critical responses to it often come in two stages; they first doubt the enhancement itself and attribute it to an artifact. Second (when they accept the enhancement), they doubt the significance of the enhancement among natural variability of space weather origin. For example, Kamogawa and Kakinami (2013) attributed the enhancement to an artifact falsely detected by the combined effect of the highly variable TEC under active geomagnetic condition and the occurrence of a tsunamigenic ionospheric hole. Here we closely examine the time series of vertical TEC before and after the 2011 Tohoku-oki earthquake. We first demonstrate that the tsunami did not make an ionospheric hole, and next confirm the reality of the enhancement using data of two other sensors, ionosonde and magnetometers. The amplitude of the preseismic TEC enhancement is within the natural variability, and its snapshot resembles to large-scale traveling ionospheric disturbances. However, distinction could be made by examining their propagation properties. Similar TEC anomalies occurred before all the M ≥ 8.5 earthquakes in this century, suggesting their seismic origin. Key Points Tsunami does not make an ionpsheric hole TEC enhancement, changes in foEs and declination started together All earthquakes exceeding M8.5 are preceded by TEC enhancements ©2013. American Geophysical Union. All Rights Reserved.
Watanabe K.,Shinshu University |
Kim B.-S.,Shinshu University |
Enomoto Y.,Toyama Industrial Technology Center |
Kim I.-S.,Shinshu University
Macromolecular Materials and Engineering | Year: 2011
A straightforward method, which is termed novel handspinning, is reported for producing uniaxially aligned sPP nanofibers. As demonstrated by SEM analysis, the morphologies of handspun sPP nanofibers are strongly dependent upon the processing conditions such as spinning method and solvent system. Compared to the normal electrospun sPP nanofibers, the handspun sPP nanofibers show smoother morphologies. FT-IR analysis demonstrates a significant difference in polymer chain conformation between the handspun and electrospun sPP nanofibers. Moreover, interestingly, the handspun sPP single nanofibers show higher Young's modulus and tensile strength than electrospun sPP single nanofibers. A novel spinning technique, "Handspinning", is presented to produce uniaxially aligned nanofibers. SEM images of handspun sPP nanofibers show a smooth surface morphology and thinner fiber diameter than for electrospun sPP nanofibers, which dramatically depend on the pulling away distance and solvent system. The handspun sPP single nanofiber shows higher Young's modulus and tensile strength. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Sakai Y.,Toyama Industrial Technology Center |
Adachi M.,Toyama Prefectural University
Japanese Journal of Applied Physics | Year: 2015
Pb(Zr,Ti)O3 and related materials have been lauded for their piezoelectric properties, but their toxicity has driven the search for alternative materials with the same high performance in electronic devices. Among these, BaTiO3-based materials are regarded as excellent substitutes. Using a screen printing method, in this study, we prepare BaTiO3 thick films on ZrO2 stabilized with 3 mol% Y2O3 (YSZ) or MgO ceramics with Pt bottom electrodes. BaTiO3 thick films prepared on YSZ and MgO substrates preferentially oriented along the a- and c-axes, respectively. The remanent polarization Pr of the MgO-based films was higher than that of the YSZ-based films (10.8 μC/cm2 vs 6.5μC/cm2) and comparable to that of BaTiO3 bulk ceramics. Thermal expansion measurements of BaTiO3, YSZ, and MgO ceramics suggested that compressive stress was exerted on the BaTiO3 thick films, causing them to orient along the c-axis. (Ba0.92Ca0.08)(Ti0.975Zr0.025)O3 thick films were also prepared on the YSZ and MgO substrates and showed similar preference for the c-axis on MgO. However, the remanent polarization of (Ba0.92Ca0.08)(Ti0.975Zr0.025)O3 thick films prepared on MgO was greater than that of bulk ceramics (14.9 μC/cm2 vs 11.0 μC/cm2). © 2015 The Japan Society of Applied Physics.
Kakiuchi S.,Toyama Industrial Technology Center
Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A | Year: 2010
The effects of the microstructure on damping capacity of magnesium alloys (AZ31B, AZ61A and AZX311) were researched. Magnesium alloys of various microstructures were changed by heat treatment and cold rolling processing. Internal friction of magnesium alloys has increased as the Vickers hardness decreases. However, it seemed that the influence of annealing and cold rolling was small to the damping characteristics on practical use. On the other hand, magnesium sheets that had been made by powder extrusion process showed good damping capacity.
Takei S.,Toyama Prefectural University |
Takei S.,Osaka University |
Mochiduki K.,Toyama Prefectural University |
Kubo N.,Toyama Prefectural University |
Yokoyama Y.,Toyama Industrial Technology Center
Applied Physics Letters | Year: 2012
This paper reports an approach using nanoparticle free polymer blends for light scattering films in liquid crystal displays. The ability to create the regularly structured circle of approximately 200 nm diameter in the light scattering film by blending two specified polymers with carboxylic acid groups and epoxy groups was demonstrated. The developed light scattering film based on thermosetting system indicated regularly structured nanomorphology, high light scattering rates of more than 3.9 at 300-600 nm of wavelength, and fast thermal cross-linking reaction at 150 °C and 60 s in thermosetting conditions for high productivity. © 2012 American Institute of Physics.