A model of a Boolean game with only one free parameter p that denotes the strength of local interaction is proposed wherein each agent acts according to the information obtained from his neighbors in the network, and those in the minority are rewarded. The simulation results indicate that the dynamic of the system is sensitive to network topology, whereby the network of larger degree variance, i.e., the system of greater information heterogeneity, leads to less system profit. The system can self-organize to a stable state and perform better than the random choice game, although only the local information is available to the agents. In addition, in heterogeneity networks, the agents with more information gain more than those with less information for a wide extent of interaction strength p.

Owing to its intrinsically lubricious property, graphene has a high potential to be an atomically thin solid lubricant for sliding interfaces. Despite its ultrahigh breaking strength at the nanoscale, graphene often fails to maintain its integrity when subjected to macroscale tribological tests. To reveal the true wear characteristics of graphene, a nanoscale diamond tip was used to scratch monolayer graphene mechanically exfoliated to SiO substrates. Our experimental results show that while graphene exhibited extraordinary wear resistance in the interior region, it could be easily damaged at the step edge under a much lower normal load (∼2 orders of magnitude smaller). Similar behavior with substantially reduced wear resistance at the edge was also observed for monatomic graphene layer on graphite surface. Using molecular dynamics simulations, we attributed this markedly weak wear resistance at the step edge to two primary mechanisms, i.e., atom-by-atom adhesive wear and peel induced rupture. Our findings shed light on the paradox that graphene is nanoscopically strong yet macroscopically weak. As step edge is ubiquitous for two-dimensional materials at the macroscale, our study also provides a guiding direction for maximizing the mechanical and tribological performance of these atomically thin materials.

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A superamphiphobic (super-repellent) surface with both water and rapeseed oil contact angle higher than 150°was prepared on a common cast iron substrate. The water and rapeseed oil contact angles were 158 ± 1.9°and 151 ± 1.7°, respectively. The sliding angles of water and rapeseed oil on the superamphiphobic surface were 2°and 16°, respectively. Scanning electron microscope images showed that many interesting microflower-like microstructures comprised many nanorods with the average diameter of about 200 nm, which were distributed on the superamphiphobic cast iron substrate. Each nanorod was composed of many smaller nanostructures and nano particles, which created interesting micro-nano binary structures similar to the surface microstructures of lotus leaves. When kept in an ambient environment for 6 months, no rust was observed on the superamphiphobic cast iron substrate surface, which showed excellent corrosion resistance.