355 resultados para rare-earths in glasses


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In this article, we review our recent advances in understanding the deformation behavior of a typical tough Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1) bulk metallic glass (BMG), as a model material, under various loading modes and strain rates, focusing particularly on the rate-dependence and formation mechanism of shear-banding. Dynamic and quasi-static mechanical experiments, including plate shear, shear punch and spherical indentation, and continuum as well as atomistic modeling on shear-banding are discussed. The results demonstrate that higher strain rate slows down the annihilation process of free volume, but promotes the free-volume coalescence, which is responsible for the rate-dependent shear banding. The physical origin of shear bands, that is the free volume softening underpinned by irreversible rearrangements of atoms, is unveiled. Finally, some concluding remarks are given.

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The history of experimental study on beta-delayed proton decays in the rare-earth region was simply reviewed. The physical results of the beta-delayed proton decays obtained at IMP, Lanzhou over the last 10 years were summarized, mainly including the first observation of 9 new beta-delayed proton precursors along the odd-Z proton drip line and the new data for 2 waiting-point nuclei in the rp-process. The results were compared and discussed with different nuclear model calculations. Finally, the perspective in near future was briefly introduced.

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The stabilization ratios.. for double-electron transfer, i.e., the cross section ratios of true double capture to total double-electron transfer, are measured in O6++ He, Ne and Ar collisions at 6 keV/u. A high.. value about 68% is obtained for the He target, while for the Ar target, the.. value is only 8%. The high R value for the He target is due to the significant direct population of the (2l, nl') configurations with high n For the Ar target, the (quasi) symmetric configurations (3l, nl') lead to the much lower.. value. Neglecting the core effects, the O6+ ion can be taken as a bare ion C6+ except the occupied 1s shell, and then the measured R values are compared with previous experimental results of C6+ projectile ions at similar impact velocity. It yields good agreement with the Ne and Ar target, while the occupied 1s shell for the O6++ He system results in a higher R value than that in C6++He collisions.