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1,613 results on '"Shimura, T."'

51. Photorefractive InGaAs/GaAs multiple quantum wells in the Franz-Keldysh geometry

Author

Iwamoto, S., Kageshima, H., Yuasa, T., Nishioka, M., Someya, T., Arakawa, Y., Fukutani, K., Shimura, T., and Kuroda, K.

Subjects
Photorefractive materials -- Research, Physics -- Research, Quantum wells -- Research, Physics
Abstract

Research describing photorefractive multiple quantum well structures is presented. With reference to Franz-Keldysh geometry properties including saturation intensity, spatial resolution, high order diffractions and electric field dependence are investigated.

Published
2001

69. Relation Between Lightning Activity of Summer and Winter Thunderclouds and Surface Electric Field Variation, Japan

Author

Michimoto, K, Shimura, T, and Suzuki, T

Subjects
Meteorology And Climatology
Abstract

In winter, active convective clouds frequently form along the coastline of the Hokuriku district, in association with strong advection of Siberian air masses over the Sea of Japan. On the other hand, in summer, many thunderclouds form in the Kanto region in the afternoon every day. Summer and winter thunderclouds were investigated by field works, operation of the C- and X-band weather radars and a car-borne fieldmill. The investigation found a very close relation between the temporal variation of 3-dimensional radar echo and surface electric field magnitude detected by a car-borne fieldmill in the case of summer thunderclouds and winter convective clouds or thunderclouds. The study probed the close relation among radar echoes, quantity of thunderclouds and surface electric field magnitude in the summer and winter seasons. We think that summer thundercloud activity can basically be equated with winter thundercloud lightning activity, except that the magnitude of surface electric field under summer thunderclouds in the case of the Kanto region cannot be equated with that under winter thunderclouds in the case of the Hokuriku district in winter.

Published
1999

84. Photorefractive effect and photochromism in the Fe-doped relaxor ferroelectric crystal Pb(Zn1/3Nb2/3)O3-PbTiO3.

Author

Sato, Y., Abe, S., Fujimura, R., Ono, H., Oda, K., Shimura, T., and Kuroda, K.

Subjects
FERROELECTRIC crystals, FERROELECTRIC devices, FERROELECTRIC thin films, ELECTRIC conductivity, FERROELECTRICITY, PHOTOCONDUCTIVITY
Abstract

The photorefractive properties of the iron-doped Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt %- and the Fe:0.1 wt %-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. [ABSTRACT FROM AUTHOR]

Published
2004
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88. Magnetic carriers of iron nanoparticles coated with a functional polymer for high throughput bioscreening

Author

Maeda, M., Kuroda, C.S., Shimura, T., Tada, M., Handa, H., Abe, M., Yamamuro, S., and Sumiyama, K.

Subjects
Iron -- Magnetic properties, Nanoparticles -- Magnetic properties, Physics
Abstract

Iron nanoparticles, 15-20 nm in size, having saturation magnetization, [M.sub.s], of 170 emu/g is synthesized. It is facilitated that nonspecific protein adsorption suppression, a requisite for nanoparticles to be applied to carriers for bioscreening.

Published
2006

90. Paternal DNA damage suppresses in vitro proliferation of mouse inner cell mass

Author

Adiga, S. K., Toyoshima, M., Shimura, T., Takeda, J., Uematsu, N., Kumar, P., and Niwa, O.

Subjects
inner cell mass proliferation, embryonic structures, lcsh:R, DNA damage, lcsh:Medicine, implantation potential, lcsh:Gynecology and obstetrics, lcsh:RG1-991
Abstract

Objective: Sperm DNA damage is known to cause developmental failure and reduction in the numbers of live offspring and the effects of damages range as diverse as embryonic death and cancer susceptibility in the offspring. Here we report the in vitro proliferation ability of the inner cell mass of the mouse embryos derived from the DNA damaged sperm and its association with post implantation developmental potential. Material and Method: Day 3.5 mouse embryos derived from the DNA damaged sperm were cultured on MEF feeder layer and proliferation ability of the inner cell mass was assessed for six days. The post implantation developmental competence was studied by feto-placental analysis on day 18 of gestation. Results: The development of embryos derived from 6 Gy irradiated sperm demonstrated heterogeneous growth on day 3.5 as approximately 1/3rd of the embryos failed to undergo compaction and demonstrated high frequency of micronuclei. In addition embryos showing developmental delay on day 3.5 failed to form any outgrowth during 6 day of in vitro culture. The fetoplacental analysis on day 18 of gestation showed a 50% reduction in the number of fetus derived from the DNA damaged sperm although the number of implantations was not affected. Conclusions: Our study demonstrates that DNA damage in sperm can lead to preimplantation embryonic developmental delay resulting in defective ICM proliferation possibly due to increased genomic instability and such embryos die in utero.

Published
2009

95. Evaluation of La0.57Sr0.38Co0.2Fe0.8O3-δ Electrode Performance Degradation Based on Three-Dimensional Microstructure Reconstruction and Electrochemical Simulation.

Author

Shimura, T., He, A., and Shikazono, N.

Subjects
ELECTRODE performance, FOCUSED ion beams, OHMIC resistance, ELECTROCHEMICAL analysis, SCANNING electron microscopy
Abstract

Time evolutions of electrochemical performance of La0.57Sr0.38Co0.2Fe0.8O3-δ (LSCF) during operation are evaluated based on threedimensional microstructural analysis and electrochemical simulation. After 100 hours of operation at 700 and 800°C, increases in polarization and ohmic resistances are observed. Segregated Sr phase is found inside theLSCFlayer after the operation at 800°C.LSCF, GDC, segregated Co phase, segregated Sr phase,GDC interlayer, interdiffusion phase, SZO phase, and YSZ electrolyte are segmented and reconstructed by focused ion beam - scanning electron microscopy (FIB-SEM) to analyze their microstructural characteristics in detail. No significant changes are observed for double phase boundary and triple phase boundary densities. Electrochemical simulations using the three-dimensional structures including all phases are carried out to predict the degradation factor. The increase in polarization resistance is well reproduced by assuming a decrease in the surface exchange rate, On the other hand, the increase in the ohmic resistance is attributed to the constriction of the ionic current in the inter-diffusion layer. [ABSTRACT FROM AUTHOR]

Published
2019
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96. Photorefractive effect and photochromism in the Fe-doped relaxor ferroelectric crystal Pb(Zn1/3Nb2/3)O3- PbTiO3

Author

Sato, Y., Abe, S., Fujimura, Ryushi, Ono, H., Oda, K., Shimura, T., and Kuroda, K.

Subjects
Materials science, Photorefractive materials, Ferroelectric materials, business.industry, Photoconductivity, Iron, Analytical chemistry, General Physics and Astronomy, Infrared spectroscopy, Light scattering, Photorefractive effect, Grating, Lead compounds, Photochromism, Crystal, Optoelectronics, Single crystals, Doping (additives), business, Absorption (electromagnetic radiation), Diffraction grating
Abstract

The photorefractive properties of the iron-doped Pb(Zn1/3Nb 2/3)O3-PbTiO3 (PZN-PT) relaxor ferroelectric single crystals were investigated by two-beam coupling experiments. The Fe:0.01 wt%- and the Fe:0.1 wt%-doped 0.91PZN-0.09PT single crystals were grown with the flux solution method. The Extinction spectrum, the electro-opric coefficient, the light-induced absorption change, and the photoconductivity were measured in these samples. The maximum gain coefficient reached to 21 cm-1, which is about twice as large as that of undoped PZN-PT. The grating formation rate decreases with the Fe concentration. 2004 American Institute of Physics.

Published
2004

98. Photorefractive and photochromic properties of Ru doped Sr0.61Ba0.39Nb2O6 crystal

Author

Fujimura, Ryushi, Kubota, E., Matoba, O., Shimura, T., and Kuroda, K.

Subjects
Materials science, Photorefractive materials, Absorption spectroscopy, business.industry, Crystal structure, Doping, Nonlinear optics, Photorefractive effect, Strontium barium niobate, Photochromism, Atomic and Molecular Physics, and Optics, Ruthenium, Strontium compounds, Electronic, Optical and Magnetic Materials, Crystal, chemistry.chemical_compound, Wavelength, Optics, chemistry, Doping (additives), Electrical and Electronic Engineering, Physical and Theoretical Chemistry, business
Abstract

We investigate the photorefractive properties of ruthenium doped strontium barium niobate by use of two-wave mixing experiments. Large gain coefficient of 19 cm-1 and fast response time of 0.4 s at 1 W/cm2 are obtained at a wavelength of 476.5 nm. We estimate photorefractive parameters using one-center model and discuss wavelength dependence of these parameters. Furthermore, this crystal exhibits strong photochromic effect in the wide spectral range by the illumination of UV light. This photochromic effect can be bleached by red-light illumination. 2002 Elsevier Science B.V. All rights reserved.

Published
2002

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