<div style="text-align:justify;"> Coding metasurface draws amounts of research interests due to its potential for achieving sophisticated functions in wave manipulation by using simple logical unit cel...<div style="text-align:justify;"> Coding metasurface draws amounts of research interests due to its potential for achieving sophisticated functions in wave manipulation by using simple logical unit cells with out-of-phase responses. In this paper, we present a novel acoustic coding metasurface structure for underwater sound scattering reduction based on pentamode metamaterials. The metasurface is composed of two types of hexagonal pentamode unit cells with phase responses of 0 and π respectively. The units are arranged in random 1-bit coding sequence to achieve low-scattering underwater acoustic stealth effect. Full-wave simulation results are in good accordance with the theoretical expectation. The optimized arrangement resulted in the distribution of scattered underwater acoustic waves and suppression of the far field scattering coefficient over a wide range of incident angles. We show that pentamode-based coding metasurface provides an efficient scheme to achieve underwater acoustic stealth by ultrathin structures. </div>展开更多
Biomimetic metallic biomaterials prepared for bone scaffolds have drawn more and more attention in recent years.However,the topological design of scaffolds is critical to cater to multi-physical requirements for effic...Biomimetic metallic biomaterials prepared for bone scaffolds have drawn more and more attention in recent years.However,the topological design of scaffolds is critical to cater to multi-physical requirements for efficient cell seeding and bone regeneration,yet remains a big scientific challenge owing to the coupling of mechanical and mass-transport properties in conventional scaffolds that lead to poor control towards favorable modulus and permeability combinations.Herein,inspired by the microstructure of natural sea urchin spines,biomimetic scaffolds constructed by pentamode metamaterials(PMs)with hierarchical structural tunability were additively manufactured via selective laser melting.The mechanical and mass-transport properties of scaffolds could be simultaneously tuned by the graded porosity(B/T ratio)and the tapering level(D/d ratio).Compared with traditional metallic biomaterials,our biomimetic PM scaffolds possess graded pore distribution,suitable strength,and significant improvements to cell seeding efficiency,permeability,and impact-tolerant capacity,and they also promote in vivo osteogenesis,indicating promising application for cell proliferation and bone regeneration using a structural innovation.展开更多
文摘<div style="text-align:justify;"> Coding metasurface draws amounts of research interests due to its potential for achieving sophisticated functions in wave manipulation by using simple logical unit cells with out-of-phase responses. In this paper, we present a novel acoustic coding metasurface structure for underwater sound scattering reduction based on pentamode metamaterials. The metasurface is composed of two types of hexagonal pentamode unit cells with phase responses of 0 and π respectively. The units are arranged in random 1-bit coding sequence to achieve low-scattering underwater acoustic stealth effect. Full-wave simulation results are in good accordance with the theoretical expectation. The optimized arrangement resulted in the distribution of scattered underwater acoustic waves and suppression of the far field scattering coefficient over a wide range of incident angles. We show that pentamode-based coding metasurface provides an efficient scheme to achieve underwater acoustic stealth by ultrathin structures. </div>
基金This work was sponsored by the National Natural Science Foundation of China(Grant No.51922044)the Key Area Research and Development Program of Guangdong Province(No.2020B090923001)the Academic frontier youth team at Huazhong University of Science and Technology(HUST)(2018QYTD04).
文摘Biomimetic metallic biomaterials prepared for bone scaffolds have drawn more and more attention in recent years.However,the topological design of scaffolds is critical to cater to multi-physical requirements for efficient cell seeding and bone regeneration,yet remains a big scientific challenge owing to the coupling of mechanical and mass-transport properties in conventional scaffolds that lead to poor control towards favorable modulus and permeability combinations.Herein,inspired by the microstructure of natural sea urchin spines,biomimetic scaffolds constructed by pentamode metamaterials(PMs)with hierarchical structural tunability were additively manufactured via selective laser melting.The mechanical and mass-transport properties of scaffolds could be simultaneously tuned by the graded porosity(B/T ratio)and the tapering level(D/d ratio).Compared with traditional metallic biomaterials,our biomimetic PM scaffolds possess graded pore distribution,suitable strength,and significant improvements to cell seeding efficiency,permeability,and impact-tolerant capacity,and they also promote in vivo osteogenesis,indicating promising application for cell proliferation and bone regeneration using a structural innovation.
