Resonant spin orientation of excitons was observed under linearly polarized quasiresonant excitation around two anticrossing points of excitons in InP quantum dots ͑QDs͒. Under the longitudinal and tilted magnetic fields of 1.5 and 2.5 T, two anticrossings of bright and dark excitons take place. At the anticrossing points, bright and dark excitons mix with each other and the wave function mixing induces the resonant spin orientation. Time-resolved circular polarization clearly showed the resonant spin orientation due to mixing of bright and dark excitons at the anticrossing points. Dark excitons can work as the carrier and spin reservoir because of their long lifetime. We demonstrated that magnetic field can control the spin entanglement and the resonant spin orientation of QDs.

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This paper discusses coil structures made from a folded flat sheet which is used for an inductor in high frequency operated battery chargers for future electrified vehicles. For AC loss reduction, a Litz wire is known to be a solution, however, since Litz wires are based on a cable type structure, planar type designs are desired for miniaturization and efficient fabrication of inductors. There exists a paper proposing planar type Litz windings using a printed circuit board for planar inductors. Our unit cell FEM analysis indicates that the stacking effect of multiple winding layers, i.e. the proximity effect between layers, was significant to its overall resistance and therefore the Litz wire pitch has to be much finer than the single board case. Thus, an effective Litz wire design, within our design requirements, requires a very fine strand width that goes beyond the fabrication capability of the vias, i.e. metalized through holes to connect different layers. In this paper, we propose novel planar Litz wire structure without vias by introducing a PCB folding technique by implementing a development chart for a coil structure with twisted strand bundle on one single sheet.