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Sendai, Japan

Tohoku Gakuin University is a private university in Sendai, Japan. It was founded under a Christian background . Wikipedia.

Sepehri-Amin H.,Japan National Institute of Materials Science | Ohkubo T.,Japan National Institute of Materials Science | Shima T.,Tohoku Gakuin University | Hono K.,Japan National Institute of Materials Science
Acta Materialia | Year: 2012

The compositions of grain boundaries (GBs) and other interfaces surrounding Nd 2Fe 14B grains in commercial Nd-Fe-B sintered magnets have been investigated by laser-assisted three-dimensional atom probe to understand the mechanism of the coercivity enhancement by post-sinter annealing. While only a slight segregation of Nd and Pr to the GBs was confirmed in the as-sintered sample, a thin Nd-rich amorphous phase layer was observed along the GBs with Cu segregation to the interfaces in the annealed sample. The segregation of Cu to NdO x/Nd 2Fe 14B interfaces was also found, suggesting that the Nd 2Fe 14B grains are enveloped by a Cu-enriched layer after the annealing. The concentration of Fe + Co in the thin GB layer was found to be as high as 65 at.%, and a model amorphous film processed by sputtering with the same composition as the thin GB layer was found to be ferromagnetic. Ferromagnetic behavior of the thin GB layer suggested that Nd 2Fe 14B grains are magnetically coupled. The coercivity mechanism of the sintered magnets is discussed based on these new findings. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Minegishi S.,Tohoku Gakuin University
IEEJ Transactions on Fundamentals and Materials | Year: 2012

The investigation research of the electrostatic discharge ESD was carried out from the viewpoint of EMC in order to clarify the mechanism of the EMI with the ESD by the EMC investigation expert committee. The transient electromagnetic noise by the ESD has the wideband frequency spectra which reach the microwave band. Therefore, the grasp of the frequency spectra of the phenomenon and generation of electromagnetic wave are very difficult. As a result of the investigation, following results were obtained. (1) A knowledge on the ESD was consolidated, and common recognition was confirmed as an EMC problem. (2) The measuring methods of transient current up to 12GHz and transient electromagnetic field up to 3GHz were established. (3) Basic data of polarity characteristics of the impulse electromagnetic wave were obtained. © 2012 The Institute of Electrical Engineers of Japan. Source

Matsuo I.,Tohoku Gakuin University
Journal of the Acoustical Society of America | Year: 2013

Bats use frequency-modulated echolocation to identify and capture moving objects in real three-dimensional space. Experimental evidence indicates that bats are capable of locating static objects with a range accuracy of less than 1 μs. A previously introduced model estimates ranges of multiple, static objects using linear frequency modulation (LFM) sound and Gaussian chirplets with a carrier frequency compatible with bat emission sweep rates. The delay time for a single object was estimated with an accuracy of about 1.3 μs by measuring the echo at a low signal-to-noise ratio (SNR). The range accuracy was dependent not only on the SNR but also the Doppler shift, which was dependent on the movements. However, it was unclear whether this model could estimate the moving object range at each timepoint. In this study, echoes were measured from the rotating pole at two receiving points by intermittently emitting LFM sounds. The model was shown to localize moving objects in two-dimensional space by accurately estimating the object's range at each timepoint. © 2013 Acoustical Society of America. Source

Long C.,Tohoku Gakuin University
Journal of Pragmatics | Year: 2010

A stepwise regression analysis of the use of apology expressions elicited in 2574 gratitude situations selected degree of 'regret' and 'expectedness' as significant predictors such that as expectedness decreased, regret increased, as did the use of apology expressions. These findings suggest that degree of regret is calculated relative to the expectedness of the act and that the use of apology expressions in gratitude situations (apology-gratitude expressions) marks an act as falling outside the boundaries of interlocutor role-relations. This interpretation, which views apology-gratitude expressions as a general strategy for negotiating interlocutor role-relations, challenges a more simplistic account of such expressions as mere markers of formal or "public" discourse (e.g., Ide, 1998). A second study of 333 Japanese 1st-9th grade students indicated that awareness of the use of apology-gratitude begins as early as 1st grade and approximates that of adults between 7th and 9th grade. The findings of this second study suggest that the negotiation of role-relations via the use of apology-gratitude expressions is acquired gradually as a part of the language socialization process. © 2009 Elsevier B.V. All rights reserved. Source

Kazmi S.M.R.,Tohoku University | Goto H.,Tohoku University | Guo H.-J.,Tohoku Gakuin University | Ichinokura O.,Tohoku University
IEEE Transactions on Industrial Electronics | Year: 2011

This paper proposes a novel solution to the problems that exist in the conventional hill climb searching (HCS) maximum power point tracking (MPPT) algorithm for the wind energy conversion system. The presented solution not only solves the tracking speed versus control efficiency tradeoff problem of HCS but also makes sure that the changing wind conditions do not lead HCS in the wrong direction. It intelligently adapts the variable step size to keep up with the rapid changes in the wind and seizes the perturbation at the maxima to yield 100% control efficiency. For this purpose, a novel peak detection capability has been devised which, in contrast with conventional peak detection, can work robustly under changing wind conditions. The proposed MPPT performs self-tuning to cope with the nonconstant efficiencies of the generatorconverter subsystemsa phenomenon quite rarely discussed in research papers so far. In addition, a smart speed-sensorless scheme has been developed to avoid the use of mechanical sensors. The experimental results confirm that the proposed algorithm is remarkably faster and more efficient than the conventional HCS. © 2006 IEEE. Source

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