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Positron annihilation lifetime spectra of MCM-41 and zeolite Y were measured at different vacuum levels. When the experiments were carried out in air, a very long lifetime component (τ4 = 35-45 ns, I4 = 15-20%) was observed for MCM-41, while the longest lifetime for zeolite Y was only 2-4 ns with an intensity of 15-25%. However, when the experiments were carried out in vacuum, the very long lifetime components could be observed for both samples, although with different intensities, ~30% for MCM-41 and ~10% for zeolite Y. For MCM-41 in air, the longest lifetime (τ4) is ~42 ns, corresponding to the ortho-positronium (o-Ps) annihilation lifetime in MCM-41 cavities. This value is slightly longer but very close to the value of 39 ns, which was estimated by using a bouncing quantum particle model. These peculiar positron annihilation characteristics were explained by air quenching mechanism of o-Ps annihilation in MCM-41. It was suggested that because of the existence of the very long lifetime component even in air, positron lifetime spectroscopy could be a very useful tool for nondestructive measurement of the cavity size of mesoporous solids such as MCM-41.

FeCoN films with 10 at.% Co content were prepared by the sputtering method. The effect of annealing on the structure and magnetic properties of FeCoN films was investigated. The as-deposited FeCoN films consist of martensite. Annealing at martensite transforms into the phase. The formed at decomposes into and at annealing temperature , and it disappears in the FeCoN film annealed at . The FeCoN films annealed at show very high saturation magnetization , which confirms the high saturation magnetization of the .

We present a simple analytical model to study the temperature evolution of a superelastic NiTi shape memory alloy (SMA) bar under cyclic tensile loading. By dividing the cycle into five characteristic stages and solving the heat transfer equations for each of the stages, we obtain the analytical expressions of the temperature evolution under the cyclic loading of different frequencies (cycle period tp) in different convective ambients (characterized by heat transfer time th). It is found that, due to latent-heat release/absorption, the specimen’s temperature oscillates during the cyclic loading, and the oscillation amplitude (δ stable ) increases with the loading frequency and reaches a saturated value in the high-frequency range (tp/th < 0.1). Moreover, due to the heat accumulated from the intrinsic mechanical dissipation (internal friction), the mean-temperature of the specimen increases with the loading frequency. The temperature rise becomes significant in the high-frequency range. These predictions quantitatively agree well with experiments. (Some figures in this article are in colour only in the electronic version)

We demonstrate that by spatially modulating the Bessel optical lattice where a Bose–Einstein condensate is loaded, we get tunable rotary orbits of nonlinear lattice modes. We show that the radially expanding or shrinking Bessel lattice can drag the nonlinear localized modes to orbits of either larger or smaller radii and the rotary velocity of nonlinear modes can be changed accordingly. The localized modes can even be transferred to the Bessel lattice core when the localized modes' rotations are stopped. Effects beyond the quasi-particle approximation such as destruction of the nonlinear modes by nonadiabatic dragging are also explored.