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Akimoto K.,Nagoya University | Emoto T.,Toyota National College of Technology
Journal of Physics Condensed Matter

Strain can reduce carrier mobility and the reliability of electronic devices and affect the growth mode of thin films and the stability of nanometer-scale crystals. To control lattice strain, a technique for measuring the minute lattice strain at surfaces and interfaces is needed. Recently, an extremely asymmetric x-ray diffraction method has been developed for this purpose. By employing Darwin's dynamical x-ray diffraction theory, quantitative evaluation of strain at surfaces and interfaces becomes possible. In this paper, we review our quantitative strain analysis studies on native SiO2/Si interfaces, reconstructed Si surfaces, Ni/Si(111)-H interfaces, sputtered III-V compound semiconductor surfaces, high-k/Si interfaces, and Au ion-implanted Si. © 2010 IOP Publishing Ltd. Source

Kano Y.,Toyota National College of Technology | Kosaka T.,Nagoya Institute of Technology | Matsui N.,Nagoya Institute of Technology
IEEE Transactions on Industrial Electronics

This paper presents a simple nonlinear magnetic analysis for axial-flux permanent-magnet machines as an assistant design tool of 3-D finite-element analysis (3D-FEA). The proposed analysis consists of an equivalent magnetic circuit and an analytical model of air-gap permeances, including saturable permeances in the core. The proposed analysis is capable of calculating the flux distribution and torque characteristics under heavy operating conditions. We verify the accuracy of the proposed analysis by comparing the results with those of 3D-FEA for various design free parameters. After verifying the accuracy of the analysis, we present our analysis-based optimum design, which realizes the maximum torque density while maintaining efficiency at the desired value. Compared to the traditional 3D-FEA, the design method proposed here has the same accuracy, while the computation time is as short as 1/21. © 2006 IEEE. Source

Kano Y.,Toyota National College of Technology
2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015

This paper presents the design optimization and performance analyses of a wound-field type brushless synchronous machine (WF-BSM) for traction drives in hybrid electric vehicles (HEVs). Research on a WF-BSM with free rare-earth magnet becomes an attractive research topic recently due to several advantages of robust rotor structure, high power capability that suitable for high-speed motor drive system applications. Furthermore, this machine has advantages of easy cooling of all active parts in the stator. The design target is the motor with maximum power more than 60kW and maximum power density more than 2.7kW/kg. The design optimization of a WF-BSM is performed by means of a finite element analysis-based genetic algorithm (GA). As the design results, the designed machine has achieved maximum power and power density of 90.8kW and 4.11kW/kg, respectively. Thus, the designed motor enables to keep the same power density in the existing IPMSM installed on a commercial HEV. © 2015 IEEE. Source

Emoto T.,Toyota National College of Technology
e-Journal of Surface Science and Nanotechnology

Extremely asymmetric x-ray diffraction is a powerful technique for observing minute strains near crystal surfaces. This work focused on the peak intensity of the rocking curve and studied the change in peak intensity with respect to the wavelength of x-rays using dynamical diffraction calculations. From the calculations assuming uniaxial strain along the depth direction of the crystal, it was found that the peak intensity becomes more sensitive to strain as the wavelength decreases below a critical value (critical wavelength λc) at which the total reflection of incident x-rays is enhanced. Comparing the profile of peak intensity vs. wavelength for a strained crystal with that for an unstrained crystal, it is clear that the introduction of compressive or tensile strain causes either enhancement or reduction of the intensity. The difference spectra generated by subtraction of the profile of peak intensity vs. wavelength for an unstrained crystal from that for a strained crystal shows a systematic change with respect to the strain parameters, the maximum strain value "0 and the thickness of the strained layer H. It is expected that we can evaluate the strain more quickly and easily by fitting the difference spectra than by using the rocking curves when the rocking curves are featureless. © 2013 The Surface Science Society of Japan. Source

Kano Y.,Toyota National College of Technology
2014 International Power Electronics Conference, IPEC-Hiroshima - ECCE Asia 2014

This paper overviews recent technical trends of research and development of non rare-earth permanent magnet motors. In particular, switched reluctance motors (SRMs) made of recent developed core materials and flux switching machines (FSMs) are reviewed. © 2014 IEEE. Source

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