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A novel route for the synthesis of boehmite nanospheres with a hollow core and the shell composed of highly crumpled AlOOH nanosheets by oxidizing Al nanopowder in pure water under mild processing conditions is described. The stepwise events of Al transformation into boehmite are followed by monitoring the pH in the reaction medium. A mechanism of formation of hollow AlOOH nanospheres with a well-defined shape and crystallinity is proposed which includes the hydration of the Al oxide passivation layer, local corrosion of metallic Al accompanied by hydrogen evolution, the rupture of the protective layer, the dissolution of Al from the particle interior and the deposition of AlOOH nanosheets on the outer surface. In contrast to previously reported methods of boehmite nanoparticle synthesis, the proposed method is simple, and environmentally friendly and allows the generation of hydrogen gas as a by-product. Due to their high surface area and high, slit-shaped nanoporosity, the synthesized AlOOH nanostructures hold promise for the development of more effective catalysts, adsorbents, vaccines and drug carriers.

A combination of theoretical and first-principles computational methods, along with experimental evidence from the literature, were used to predict the existence of a scaling law for the electrocaloric temperature change in antiferroelectric materials. We show that the temperature change scales quadratically with electric field, allowing a simple transformation to collapse the set of ΔT(E) onto a single curve. This offers a unique method that can be used to predict electrocaloric behavior beyond the limits of present measurement ranges or in regions where data are not yet available.

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Partial charge compensation in ferroelectric nanostructures is known to play a critical role in stabilizing equilibrium domain patterns. We use first-principles-based simulations to study the effect of partial charge compensation on the response of polarization to the electric field in PbTiO3 and BaTiO3 ultrathin films. Computational data predict that the response can be altered at the qualitative level by tailoring partial charge compensation. We report an unusual transition from ferroelectric to antiferroelectric to dielectric behavior induced by the change in the amount of compensating charge. Interestingly, films with antiferroelectric features exhibit superior potential for energy storage applications.

In this article, we present the results of the research into the characteristics of the conditions of heating and explosive destruction of Al-Cu, Fe-Ti, Fe-Cu, and Fe-Pb wires under a pulse of current with the density of 107 A/cm2. It has been shown that the energy that is deposited into the wire may depend on the relation between the thermophysical parameters and specific electric resistivity of the metals. It has been determined that under a pulse of current, the wires may explode synchronously or non-synchronously. During a synchronous explosion of wires, a single voltage pulse is generated. In the case of non-synchronous explosion, the wires explode in a succession, thus generating two voltage pulses. We suggested a dimensionless parameter that allows for predicting whether an electrical explosion of two wires of dissimilar metals is synchronous or non-synchronous. According to the research findings, non-synchronous nature of wire explosion may impact the formation of bimetallic particles through the explosion of two intertwined wires made of dissimilar metals.

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