Inspired by the ability of tree frog toes to regulate body fluids, this control mechanism is applied to the tooth surface of slewing bearing (AISI 4140 steel (AS)) by adopting the regular hexagonal microtexture. SnAgCu-TiC (SACT) lubricants are filled in the microtextures. Results of two-factor analysis of variance show that there is a significant interaction between the microtexture and lubricants. When the microtextures with 1000 µm side are filled with SnAgCu-4 wt% nano-TiC (AS-SACT410), coefficient of friction (COF) of sample is the lowest. Compared with AS (0.437), COF of AS-SACT410 is reduced to 0.085, decreased by 80.55%. Macroscopic anti-friction originates because SnAgCu wraps around nano-TiC to form tribofilms containing submicron rollers, achieving substantially reduced COF.
Mao Junqiang,Cao Huimei,Liu Jie,Zhou Xin,Fan Qingrui,Wang Jianjun
Nature provides diverse models for manufacturing complex and hierarchical materials by controlling molecular assembly at scales ranging from sub-nano to macroscale. However, developing artificial strategies for manufacturing hierarchical materials with comparable machining capabilities to nature is extremely challenging. Here, a templated freezing assembly strategy is reported, enabling simultaneously regulating molecular assembly spatiotemporally to obtain hierarchical materials with structure control from sub-nano to macroscale. In this way, unique centimeter-scale freestanding nanofilms are assembled from diverse molecules, e.g. , proteins and conjugated polymers. A generated silk fibroin (SF) nanofilm presents a tunable β -sheet fraction from 5% to 47%, fiber width from 30 to 3,000 nm, and micro-textures with desired shapes. Such a strategy will lay the foundation for customizing hierarchical functional materials from single or multi-component molecules, e.g. , desired bio-scaffolds with controlled cell adhesion.
An ideal anti-counterfeiting label not only needs to be unclonable and accurate but also must consider cost and efficiency. But the traditional physical unclonable function (PUF) recognition technology must match all the images in a database one by one. The matching time increases with the number of samples. Here, a new kind of PUF anti-counterfeiting label is introduced with high modifiability, low reagent cost (2.1 × 10 −4 USD), simple and fast authentication (overall time 12.17 s), high encoding capacity (2.1 × 10 623 ), and its identification software. All inorganic perovskite nanocrystalline films with clonable micro-profile and unclonable micro-texture are prepared by laser engraving for lyophilic patterning, liquid strip sliding for high throughput droplet generation, and evaporative self-assembling for thin film deposition. A variety of crystal film profile shapes can be used as “specificator” for image recognition, and the verification time of recognition technology based on this divide-and-conquer strategy can be decreased by more than 20 times.
危险品化学品经营许可证（带存储）