Search

Current vector control of a resonant-type wireless power transfer system with 2D transmitting (Tx) coils is presented. The equivalent circuit model between two Tx and one receiving coils is derived in d–q coordinates. The control method to obtain the maximum power transmission efficiency is proposed. The experimental results are provided to verify the proposed control method.

In this paper, we apply the Cauchy method, the LPF, the SVD and the TLS theory using the RCS data in the low frequency band and predict the RCS data in the high frequency band. As the predicted frequency increases, the error between the original data and the predicted data is confirmed.

We studied the effects of WC particle size and volume fraction on the magnitude and distribution of thermal residual stresses (TRS) in WC–Ni cemented carbide composites by neutron powder diffraction. Samples of high (0.3) and low (0.1) Ni volume fraction and coarse (1.7 m) and fine (0.5 m) WC particle size were employed. Thermal residual strain and stress values were obtained at temperatures between 100 and 900 K. Moreover, the magnitude of the mean (compressive) WC stress increased as WC fraction decreased, while the mean (tensile) Ni stress did the opposite. For both phases, stresses were highest for fine WC particles, reaching over 3 GPa in Ni. Elastic strain distributions, due to the sharp edges and corners of WC particles, were characterized by analyzing diffraction peak widths. The range of stress increased with the magnitude of the TRS. Even though the mean TRS is compressive in WC, regions of tension exist, and, for Ni, regions of compression are present.

We investigated the reaction chemistry of metal contacts to GaN during annealing using X-ray photoelectron spectroscopy (XPS). GaN decomposition was estimated, using XPS, to occur in N-2 annealed Ni-alloy contacts at 550 degreesC. The reaction was greatly accelerated by the catalytic effect of Au and Pt. The decomposition was correlated with the rapid degradation of electrical properties during annealing. The results suggest that high-temperature applications may be critically limited by the degradation of metal contacts especially due to activated Ni reactivity in Ni-alloyed contacts. Meanwhile, the thermal stability of Ni/Au contact greatly improves by suppressing the activated Ni reactivity, which is able to be obtained by forming preferential Ni-O bonding through annealing in air.

The anisotropic relaxation of differential thermal residual stress in WC-17wt.%(85Co-15Ni) cermets subjected to compressive plastic strain under monotonic and cyclic loading has been studied. Results were obtained via triaxial stress measurements using neutron diffraction. The residual stress in cylindrical specimens loaded uniaxially along the cylinder axis was observed to decrease with increasing plastic strain. Although relaxation occurred both perpendicular and parallel to the loading direction, i.e. radially and axially, it was observed to be greater in the radial direction and this trend was observed to increase with increasing plastic strain. A qualitative model for the observed behavior is proposed.

not Available.

We investigated the chemical structure of actual oxide cathode emission materials using soft x-ray absorption spectroscopy. High-energy resolution spectra of the Ba 3d absorption edges reveal that the Ba content significantly increases on the surface layers of oxide cathodes down to several tens of nanometers in depth, after the cathode activation process. Furthermore, we will demonstrate that the excess Ba on the surface is only slightly driven by thermal energy, but rather it is induced by the voltage difference applied during cathode activation. This result suggests that the rate controlling step of the Ba enrichment on the surface during activation is the electrolytic transport of Ba ion from the bulk powder to the interface. We assume that the Ba enrichment on the surface originates from the depletion of barium in bulk powder by the electrolytic transport.

The present invention provides a method of fabricating a micro hollow tube, more specifically, a method of fabricating a micro hollow tube by template-free localized electrochemical deposition, in which the micro hollow tube is fabricated by the accurate control of the distribution of the electric field strength during deposition with precise interplay of the applied voltage and the distance between the microelectrode and the grown structure.