[en] The present paper aims to investigate the microstructural differences of models used in nanoporous metals and research on the mechanical response of various morphological architectures, including cube, gyroid, diamond and stochastic bicontinuous structures. By using molecular dynamics simulations, the influential parameters of architectural morphology, relative density and ligament diameter on the mechanical properties of nanoporous gold under uniaxial tension are presented and further compared with current constitutive theory and experimental results of the literature. The differences among those structures are critically demonstrated and addressed. Results present that the Young’s modulus as a function of relative density and the yield strength as a function of ligament diameter both display power-law relation but the scaling exponents vary with the microstructures. The modulus of stochastic bicontinuous structures is in better agreement with the experimental results. The relationship between yield stress and relative density is approximately linear, indicating the yielding behavior may be dominated by the yielding of ligaments in the process of deformation. These results promise much for the design of nanoporous structures with tunable, desirable mechanical properties stemming from various microstructures. (paper)

[en] Highlights: • MD simulations have been carried out to explore mechanical behaviors of nanocrystalline platinum. • Effects of grain size and temperature on the mechanical properties have been investigated. • The inverse Hall-Petch relation below grain size of 14.1 nm is observed. • The modulus of grain boundary is about 42% of that of grain core. -- Abstract: A series of molecular dynamics simulations has been carried out to study the mechanical properties of nanocrystalline platinum. The effects of average grain size and temperature on mechanical behaviors are discussed. The simulated uniaxial tensile results indicate the presence of a critical average grain size about 14.1 nm, for which there is an inversion of the conventional Hall-Petch relation at temperature of 300 K. The transition can be explained by a change of dominant deformation mechanism from dislocation motion for average grain size above 14.1 nm to grain boundary sliding for smaller grain size. The Young's modulus shows a linear relationship with the reciprocal of grain size, and the modulus of the grain boundary is about 42% of that of the grain core at 300 K. The parameters of mechanical properties, including Young's modulus, ultimate strength, yield stress and flow stress, decrease with the increase of temperature. It is noteworthy that the critical average grain size for the inversion of the Hall-Petch relation is sensitive to temperature and the Young's modulus has an approximate linear relation with the temperature. The results will accelerate its functional applications of nanocrystalline materials.

[en] Highlights: • A Poly(deep eutectic solvent)@Biomass was prepared as a novel separation medium. • The Poly(DES)@BioMs effectively removed trace DNA toxic compounds. • The removal process was based on multi-physical interactions. • The removal process was investigated using equilibrium/kinetic models. • The removal mechanisms were explored using molecular simulations. DNA toxic compounds (DNA-T-Cs), even in trace amounts, seriously threaten human health and must be completely eliminated. However, the currently used separation media face great challenges in removing trace DNA-T-Cs. Based on the functional advantages of deep eutectic solvents (DESs) and the natural features of biomass (BioM), a series of Poly(DES)@BioMs functioning as adsorbents were prepared for the removal of aromatic/hetero-atomic DNA-T-Cs at the ppm level. After optimisation of experimental conditions, the removal efficiency for DNA-T-Cs ranged from 92.4% to 96.0% with an initial concentration of 20.0 ppm, a temperature of 30 °C, duration of 30 min, and pH of 7.0. The removal processes between the DNA-T-Cs and Poly(DES)@BioMs are well described in the Temkin equilibrium and second-order kinetic adsorption models, and the desorption processes are well shown in the Korsmeryer–Peppas equilibrium and zero-order kinetic models. Molecular simulations revealed that the removal interactions include hydrogen bonding, π–π stacking, and hydrophobic/hydrophilic effects. The removal efficiency for the DNA-T-Cs at 8.0 ppm in industrial sewage ranged from 69.7% to 102%, while the removal efficiency for the DNA-T-Cs standing alone at 20.0 ppm in a methyl violet drug solution was 95.4%, confirming that the Poly(DES)@BioMs effectively removed trace DNA-T-Cs in field samples.