The self-assembly of granular spheres under simple 1D sinusoidal vibration is studied and the corresponding A – f phase diagram is established.

As granular particles in a packing are athermal, their self-assembly has to be realized with the input of energy via walls. But different manners of energy input, e.g., through tapping or shearing walls, have not been discriminated previously. We address this problem in the self-assembly of identical granular spheres in prism-like containers subjected to one-dimensional (1D) vertical vibration by numerical simulations. The edge lengths or diameter of the containers are the integer multiples of the particle diameter. When energy is input with the vibration, the particles can self-assemble into mainly mixed FCC (face-centred-cubic) and HCP (hexagonal-close-packed) structures from the bottom wall and/or the side walls. According to different movements of the walls, the shear-induced and tap-induced self-assemblies are distinguished. These two self-assembly modes can emerge solely or simultaneously, with different but overlapping regions in the vibration amplitude and frequency phase diagram. The structures of the self-assembly from the two modes also present different features, suggesting different formation mechanisms. Moreover, it is found that the close-packed planes of the ordered clusters formed from different walls are often misaligned, leading to conflicts in the self-assembly of the whole system. These findings are helpful for both the understanding and controlling of the self-assembly of granular particles and other similar athermal and low-thermal systems.

A simple hydrothermal method for the synthesis of Ag0.35V2O5 nanobelts with the assistance of sodium dodecyl sulfate (SDS) is reported in this study. The experimental variables that may affect the nanoparticle structures were investigated. And several advanced techniques, such as TEM, HRTEM, X-ray diffraction (XRD), were used to characterize the morphology and composition of the as-prepared nanobelts. The mechanism of the formation and growth of Ag0.35V2O5 nanobelts was also investigated and discussed. The results show that SDS, as a weak reducing agent, plays a crucial role in the formation of Ag0.35V2O5. According to N2 sorption isothermals, the as-prepared Ag0.35V2O5 nanobelts are found to exhibit relative high surface area. The gas sensing performance of the Ag0.35V2O5 nanobelts towards organic amine was tested. It is found that the nanobelts show superior sensitivity of amine(s) to V2O5 particles, lower detection limit (5 ppm), and higher selectivity of amine versus ammonia at an optimized working temperature of ~260 °C. Moreover, the density functional theory (DFT) simulation was conducted to better understand the sensing mechanism. These findings may be useful in designing promising materials to detect amine gases for medical or food industrial applications.