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Your search keyword '"Tsujimoto, Kazuki"' showing total 17 results
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17 results on '"Tsujimoto, Kazuki"'

1. Reservoir computing with dipole-coupled nanomagnets

Author

Nomura, Hikaru, Furuta, Taishi, Tsujimoto, Kazuki, Kuwabiraki, Yuki, Peper, Ferdinand, Tamura, Eiiti, Miwa, Shinji, Goto, Minori, Nakatani, Ryoichi, and Suzuki, Yoshishige

Subjects
Computer Science - Emerging Technologies, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The feasibility of reservoir computing based on dipole-coupled nanomagnets is demonstrated using micro-magnetic simulations. The reservoir consists of an 2x10 array of nanomagnets. The static-magnetization directions of the nanomagnets are used as reservoir states. To update these states, we change the magnetization of one nanomagnet according to a single-bit-sequential signal. We also change the uniaxial anisotropy of the other nanomagnets using a voltage-induced magnetic-anisotropy change to enhance information flow, storage, and linear/nonlinear calculations. Binary tasks with AND, OR, and XOR operations were performed to evaluate the performance of the magnetic-array reservoir. The reservoir-computing output matrix was found to be trainable to perform AND, OR, and XOR operations with an input delay of up to three bits., Comment: 14 pages, 4 figures

Published
2018
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9. Reservoir computing with dipole-coupled nanomagnets

Author

Nomura, Hikaru, primary, Furuta, Taishi, additional, Tsujimoto, Kazuki, additional, Kuwabiraki, Yuki, additional, Peper, Ferdinand, additional, Tamura, Eiiti, additional, Miwa, Shinji, additional, Goto, Minori, additional, Nakatani, Ryoichi, additional, and Suzuki, Yoshishige, additional

Published
2019
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10. Reservoir computing with two-bit input task using dipole-coupled nanomagnet array.

Author

Nomura, Hikaru, Tsujimoto, Kazuki, Goto, Minori, Samura, Naoki, Nakatani, Ryoichi, and Suzuki, Yoshishige

Abstract

Reservoir computing (RC), which utilizes physical phenomena, is a candidate for low energy consumption recurrent neural networks. Recently, we proposed RC which uses a dipole-coupled nanomagnet array as a reservoir, which applies the direction of the static magnetic moment of each nanomagnet as a node state in the array. It is possible to learn binary tasks with one-bit input data using this reservoir. Moreover, more complex tasks such as motion detection utilize multi-bit input data. This study simulates a two-bit binary input RC by employing the dipole coupled nanomagnet array as a reservoir. We apply a binary task with two-bit input data, which requires a memory capacity and non-linear computing capability of the reservoir. Due to the simulations with a macrospin model at a temperature of 0 K, this RC was able to learn these binary tasks by utilizing 24 nanomagnets. [ABSTRACT FROM AUTHOR]

Published
2020
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15. Doping effects in Sb2S3 absorber for full-inorganic printed solar cells with 5.7% conversion efficiency.

Author

Ito, Seigo, Tsujimoto, Kazuki, Nguyen, Duy-Cuong, Manabe, Kyohei, and Nishino, Hitoshi

Subjects
*SEMICONDUCTOR doping, *STIBNITE, *ENERGY conversion, *ABSORPTION, *SOLAR cells, *WAVELENGTHS, *PHOTOCURRENTS
Abstract

Abstract: Ti, Zn, and Bi were doped into the Sb2S3 extremely thin absorber (ETA) of an all-solid-state, fully inorganic printed solar cell. Bi doping shifted the Sb2S3 absorption edge to longer wavelength and Bi-doped Sb2S3 was aggregated on the TiO2 electrodes, which resulted in photocurrent deterioration. In contrast, Ti and Zn doping did not shift the absorption edge, but improved the photocurrent. The best photocurrent density of 16.3 mA cm−2 was achieved with Ti doping (5 at% to Sb), resulting in the best conversion efficiency of 5.7%. [Copyright &y& Elsevier]

Published
2013
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16. TiO2Surface Treatment Effects by Mg2+, Ba2+, and Al3+on Sb2S3Extremely Thin Absorber Solar Cells

Author

Tsujimoto, Kazuki, Nguyen, Duy-Cuong, Ito, Seigo, Nishino, Hitoshi, Matsuyoshi, Hiroaki, Konno, Akinori, Kumara, G. R. Asoka, and Tennakone, Kirthi

Abstract

Sb2S3-based extremely thin absorber (ETA) solar cells of structure, , was fabricated with porous TiO2surface treating by Mg2+, Ba2+, and Al3+to be full-inorganic printed solar cells. The fabrication parameters of the ETA structure were optimized and the photovoltaic characteristics were improved significantly when double treatment in Mg2+and Ba2+were introduced. Best cells obtained using double treatment in Mg2+and Ba2+attained a short-circuit photocurrent of 13.4 mA/cm2, a open-circuit voltage of 0.584 V, a fill factor of 0.525, and a conversion efficiency 4.10% at 1 sun irradiation.

Published
2012
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17. 10% Efficiency Dye-sensitized Solar Cells Using P25 TiO2Nanocrystalline Electrode Prepared by a Bead-milling Method

Author

Yamamoto, Yasuhiro, Kawaraya, Masahide, Segawa, Hiroshi, Uchida, Satoshi, Kano, Junya, Saito, Fumio, Tsujimoto, Kazuki, Saito, Tsubasa, and Ito, Seigo

Abstract

Dispersions of TiO2nanoparticles were prepared from titania powder (P25, Degussa) using a bead-mill method. The dispersion was controlled by the mixing time and was observed using dynamic laser-light scattering. TiO2screen-printing pastes were prepared from the TiO2dispersions for application as photoelectrodes in dye-sensitized solar cells (DSSCs). The coated nanocrystalline TiO2electrodes were evaluated using X-ray diffraction (XRD) and a haze meter. The shape and crystallinity of the TiO2nanoparticles were not changed, but the transparency was improved by the bead-milling process. However, aluminum contamination on the TiO2surface was found to increase with bead-milling time. A TiO2paste prepared from an optimized dispersion was used to fabricate a DSSC with 10% photoenergy-conversion efficiency.

Published
2011
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