摘要：A simple uniaxial oedometric system is developed to test the elastic modulus of granular materials. The stress- strain relationship is first measured under conditions of uniaxial compression with additional lateral stress and strain, then the elastic modulus of the material is determined by the linear fitting method. It is found that the modulus is positively correlated to the grain size and negatively correlated to the container size. Arching and dragging are revealed to be the mechanism of such correlations by using the digital image correlation method and the pressure film technology based on the statistical method.

摘要：智能仿生软材料是近年来科学研究的重点之一.液晶高分子材料是众多软材料中最有发展潜力的材料之一.目前通过液晶高分子材料制备具有复杂功能和多种响应的仿生器件主要通过两种方法,其一是引入多种响应性基团,赋予材料多重响应.另一个是构建单一刺激下具有变形变色协同功能的材料.然而,结合这两种策略,构建既具有多重刺激响应,又能协同变形变色的新型液晶高分子仍然是一个挑战.为此,本工作通过结合光响应性液晶网络和亲水的聚(2-羧乙基丙烯酸酯共丙烯酸)层(PC),制备了一种光和湿度双重响应的软驱动器.在紫外光的驱动下,偶氮苯的分子异构驱动复合薄膜的各向异性形变.环境湿度的变化能使亲水的PC层发生溶胀和脱水,使薄膜发生另一模式的形变.由于薄膜内部荧光分子与水分子的协同作用,PC膜的荧光强度增强.由于整合了双重响应性和协同行为,这种新型的双响应驱动器在制造智能软体机器人方面具有较大的潜力.通过合理的设计,我们制备了一个光驱动的智能软体机器人.该机器人表现出检测水、改变运动模式和荧光强度的能力,在构筑具有识别、响应和自我调整能力的多功能软体机器人方面具有实际应用潜力.

摘要：Hydroxyapatite(HA)nanoparticles and silver(Ag)nanoparticles are expected to enable desirable bioactivity and antibac-terial properties on biopolymer ***,interfacial adhesion between HA/Ag and the biopolymer is poor due to the large physicochemical differences between these *** this study,poly L-lactic acid(PLLA)powder was first surface-modified with bioactive polydopamine(PDA)in an alkaline ***,HA and Ag nanoparticles were grown in situ on the PDA-coated PLLA powder,which was then adhered to the porous bone scaffold using a selective laser-sintering *** showed that HA and Ag nanoparticles were homogenously distributed in the matrix,with enhanced mechanical *** body fluid bioactivity tests showed that the in situ grown HA-endowed scaffold shows excellent *** vitro tests confirmed that the scaffold exhibits favorable biocompatibility with human umbilical cord mesenchymal stem cells,as well as strong antibacterial activity against Gram-negative Escherichia ***,in vivo assays indicated that the scaffold promoted bone generation,with a new bone area fraction of 71.8%after 8 weeks’implantation,without inflammation.