Papers by Tomohiro Keishi
Fast Diagonalization of Pseudopotential Hamiltonians via the double-exponential integration method
An Iterative Method for Generating Pseudopotentials II
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 1998
8a-YJ-10 An Iterative Method for Generating Pseudopotentials
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 1997
30p-YH-12 A New Preconditioning Scheme
Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 1997
Advances in numerical analysis techniques and the advent of high-speed, high-capacity analytical ... more Advances in numerical analysis techniques and the advent of high-speed, high-capacity analytical hardware, such as the personal computer, have made it possible to perform electromagnetic field analysis using the finite element method and other numerical analysis techniques, thus making investigation of even the most complex electromagnetic phenomena possible. As such, electromagnetic field analysis has become an indispensable tool in the design and development of electrical devices and appliances(1). As electromagnetic field analysis software has become increasingly powerful in recent years, analysis can now be performed very simply by just inputting the shape and setting conditions. When performing analysis, however, it is necessary to construct an electromagnetic field analysis model and evaluate analysis results appropriately. In order to do this, an understanding of electromagnetic phenomena based on electromagnetic theory is useful. In an ideal situation, such electromagnetic f...
Recently, global warming has become a serious social issue. To tackle this issue, the automobile ... more Recently, global warming has become a serious social issue. To tackle this issue, the automobile companies are concentrating on the development of environmentallyfriendly automobiles, such as the hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), electric vehicle (EV) and fuel cell vehicle (FCV). To promote the dissemination of these eco-friendly vehicles, it is vital to improve their driving performance and power acceleration as well as energy efficiency to the level of the gasoline vehicle performance. In this regard, the converter plays an important role, specifically to increase the battery voltage for the high power motor and recharge the EV and PHEV batteries from household outlets. In response to these varied demands of the converter, automakers are trying to develop small and cost-efficient converters. Sumitomo Electric Industries, Ltd. is working to develop low-cost and compact reactors, one of the core components for the converter. In our study, we deve...
Connection system with an associated process
Connection system and method for an electrically operated vehicle
IEEJ Transactions on Industry Applications, 1988
A connection system and a connection method
Connection system and connection method for an electric automotive vehicle
Connecting system and a connection method
Development of a Method to Predict Fatigue Failure Life of Junction Block Bracket Using CAE
SAE Technical Paper Series, 2001
Materials Transactions, JIM, 1999
Japan Journal of Industrial and Applied Mathematics, 2000
We present an iterative procedure to generate first-principles, norm-conserving pseudopo- tential... more We present an iterative procedure to generate first-principles, norm-conserving pseudopo- tentials which are of an analytic form and separable by construction with fewer nonlocal projectors than conventional ones. The procedure consists of two steps: First, reference pseudowavefunctions and eigenvalues for an atom are determined by a conventional method. Second, trial pseudowavefunctions and eigenvalues are calculated for the pseudopotentials with adjustable parameters repeatedly until they match the reference ones within some tolerance. The pseudopotentials allow us to evaluate Hamiltonian matrix elements efficiently and less likely to yield spurious solution. Examples for copper and zinc are shown.
Computational Materials Science, 1999
We propose a preconditioning scheme for diagonalizing large Hamiltonian matrices arising in ®rst-... more We propose a preconditioning scheme for diagonalizing large Hamiltonian matrices arising in ®rst-principles planewave pseudopotential calculations. The new scheme is based on the Neumann expansion for the inverse, shifted Hamiltonian from which only a nonlocal part is omitted. The preconditioner is applied to a gradient vector using the fast Fourier transformation technique. In the framework of the Davidson-type diagonalization algorithm, we have found the present preconditioning scheme to be more ecient than widely accepted diagonal scaling methods.
Electromagnetic coupling device for charging an electric motor vehicle
Development of Superconducting Bending Magnets for the SR Ring
The superconducting bending magnets with a bending radius of 0.5m and magnetic field of 4.0T have... more The superconducting bending magnets with a bending radius of 0.5m and magnetic field of 4.0T have been developed. The bending angle is 90 degrees so that four magnets are in stalled in the synchrotron radiation ring whose size is 3mX5m. The main coils of the bending magnets are the iron-free curvature dipole coils and the conductors are 3-divided keystone type. The shim coils are epoxy-molded quadrupole coils installed on the beam duct directly. The design of these coils was accomplished using computer simulation. The designed electron beam energy is 615 MeV and the radiation power from the beam to the magnet is 1kW so that the absorber cooled by liquid nitrogen is set in the beam duct. Test results validated the design.
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Papers by Tomohiro Keishi