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A significant enhancement in corrosion resistance by Y microalloying was achieved for the Mg–8Sn–1Zn–1Al (wt%) alloy in the extruded condition. Average corrosion rates obtained by immersion tests in 0.6 M NaCl solution at 25 °C were 4.2 and 12.7 mm y−1 for the alloys with and without microalloying with 0.04 wt% Y, respectively. Microstructural investigations indicated that the enhanced corrosion resistance is a result of a transition in a type of second-phase particles toward lowering the difference in electrochemical nobility between the α-Mg and these particles, thereby reducing the susceptibility of the alloy to microgalvanic corrosion.

A commercial Mg–6Zn–0.5Zr alloy was subjected to low-temperature indirect extrusion for grain refinement and the tensile properties of the extruded alloy at 250 °C were investigated. After extrusion, the alloy showed finely recrystallized grains with an average size of 1.6 μm. High-strain-rate superplasticity was observed in the fine-grained alloy, which exhibited a tensile elongation of up to 800% at a strain rate of 0.01 s−1. Experimental results demonstrating the occurrence of grain boundary sliding during the high-strain-rate superplastic deformation are presented.

A concentrating photovoltaic (CPV) cell exhibits the highest conversion efficiency among any solar cells. However, the further enhancement of the CPV efficiency is strongly limited by the heat generation at high solar concentrations. Here, we demonstrate a concentrating photovoltaic/thermoelectric hybrid generator using a single-junction, GaAs-based solar cell and a conventional thermoelectric module as a model system. Our hybrid generator gives rise to the conversion efficiency larger than the single CPV cell by ~3% at the solar concentration of 50 suns. Controlling thermal flow in the hybrid generator and the Peltier cooling effect is the key to achieving high efficiency. Our result provides a framework for designing a highly-efficient hybrid generator using both photo-electric and photo-thermal effects for the clean-energy production.

We explore the optimal condition for cylindrical core/shell hard-soft exchange-coupled magnetic nanostructures by obtaining full hysteresis loops for various geometries by obtaining full hysteresis loops for various geometrical variables, including the dimensional scale and soft/hard-magnetic phase volume ratio through micromagnetic simulations. For achieving maximum energy product (BH), it is essential to increase the demagnetizing field by increasing the volume fraction of the soft magnet while maintaining a positive nucleation field and, which can be possible by the scaling-down. To scale up the nanostructure to a bulk magnet having high BH can be achieved by forming an array of needle-shaped exchange-coupled cylinders. These findings could lead to the flexible design and scalable fabrication of exchange-coupled permanent magnets.

The corrosion resistance of conventional and experimental Mg–3Al–1Zn-based alloys with different Mn and Y content was comparatively investigated. After immersion for 72 h in a 0.6 M NaCl solution at 25 °C, an experimental Mg–3Al–1Zn–0.05Mn–0.03Y alloy exhibited a corrosion rate of 0.91 mm y−1, which is about four times slower than that of a conventional Mg–3Al–1Zn–0.3Mn alloy. Microstructural factors underlying the improved corrosion resistance achieved by the trace additions of Mn and Y are discussed.

The susceptibility spectra originating from both relaxation processes of reversible domain wall motion and magnetization rotation are decomposed from the susceptibility spectrum for 3% SiFe samples implanted by N-ion in the fluence range of n=5×10−5–5×1018 ions/cm2. The static susceptibilities due to domain wall motion and magnetization rotation are maximum at n=5×1017 ions/cm2. The relaxation frequencies of domain wall motion and magnetization rotation are not changed significantly up to n=5×1017 ions/cm2, and then rapidly increased with the further increase in the ion fluence. The variation of static susceptibilities and relaxation frequencies with n indicate that increase in number of pinning sites for n⩽5×1017 ions/cm2 to facilitate magnetization, and then increase in internal stress for n>5×1017 ions/cm2 to hinder magnetization.