钢纤维对UHPC拉伸性能及其拔出行为的影响

采用单轴拉伸试验和单丝拉拔试验探究了钢纤维形状、长度与直径对超高性能混凝土(UH-PC)拉伸性能及钢纤维拔出行为的影响,并结合部分单丝拉拔试验样品的钢纤维表面形貌和钢纤维-基体界面的扫描电子显微镜(SEM)观察结果,对前述影响进行了合理解释.结果表明:掺有端钩型钢纤维的UHPC拉伸性能和钢纤维单丝拉拔性能普遍优于同直径...     

Layered Materials in the Magnesium Ion Batteries: Development History,Materials Structure,and Energy Storage Mechanism

Layered crystal materials have blazed a promising trail in the design and optimization of electrodes for magnesium ion batteries (MIBs). The layered crystal materials effectively improve the migration kinetics of the Mg²⁺ storage process to deliver a high energy and power density. To meet the future demand for high-performance MIBs, significant work has been applied to layered crystal materials, including crystal modification, mechanism investigation, and micro/nanostructure design. Herein, this review presents a comprehensive overview of layered crystal materials applied to MIBs, from development history to current applications. It focuses on the relationship between the layered crystal structure and the energy storage mechanism. Meanwhile, recent achievements in the design principles of layered crystal materials and their application to electrodes are summarized. Finally, future perspectives on the application of layered materials in MIBs are presented. The overview of the development process and structural characteristics contributes to a thorough understanding of these materials, while a discussion of design strategies and practical applications can inspire further research. Therefore, this review provides guidance and assistance for constructing high-performance MIBs.     

Sustainable Droplet Manipulation on Ultrafast Lubricant Self-Mediating Photothermal Slippery Surfaces

Designing intelligent slippery surfaces for droplet manipulation is critical for many applications from drug delivery to bio-analysis, while is of great challenging in sustainability for inescapable wastage of lubricant layer. Herein, an ultrafast lubricant self-mediating (self-replenishing/-absorbing) photothermal slippery surface is designed that achieves sustainable transport of droplet under the irradiation of near infrared light (NIL) even if the lubricant layer is wiped clean completely, as well as at other man-made extreme conditions. The ultrafast lubricant self-mediating performance is caused by synergistic effects of interconnection of porous structure and photothermal expansion of the material. When lubricant on surface is lost, photothermal expansion of material can quickly squeeze the lubricant inside the base to flow into and out of the interconnected porous structure to generate a fresh lubricant layer. Attractively, when the NIL is turned off, the rebuilt lubricant layer can be swiftly self-absorbed into the porous to inhibit unnecessary wastage. Moreover, an arbitrary split of droplet in desired configurations can be achieved by controlling the NIL irradiating route. This sustainable droplet manipulation induced by ultrafast lubricant self-mediating can be extensively applied in microfluidics and micro-reactor settings.     

A vision monitoring system for multipoint deflection of large-span bridge based on camera networking

This paper proposes a vision monitoring system for multipoint deflection of a large-span bridge that can well compensate the camera motion–induced errors. The camera network system (CNS) consists of a series of dual-camera stations that are linked with the cooperative markers. The infrared illumination supplement device is integrated in the camera station and the regular double-sided prism is selected as the cooperative marker to realize 24-h continuous monitoring. The feasibility and efficiency of CNS are verified by conducting a field test inside the steel box girders of a suspension bridge with a length of 1038 m. The results show that the proposed camera networking method can well solve the problem of the large-scale high-precision monitoring under unstable measuring platform. For the kilometer-level flexible bridge, CNS can meet submillimeter precision in quasi-static measurement, and can also provide deflection data similar to the conventional robotic total station and connecting pipe system in long-term monitoring. The geometric alignment of large-span bridges with dense multimeasuring points can be automatically monitored and recorded by CNS. The observed deflections of the studied suspension bridge are dominated with the vehicle load and wind load in the short term and are correlated with the temperature change in the long term. The proposed CNS can provide a new option for the bridge deflection monitoring and provide new parameters for bridge safety evaluation.     

Polar Layered Bismuth-Rich Oxyhalide Piezoelectrics Bi4O5X2 (XBr,I): Efficient Piezocatalytic Pure Water Splitting and Interlayer Anion-Dependent Activity

Piezocatalytic pure water splitting for H₂ evolution carries the virtues of efficacious utilization of mechanical energy, easy operation, and high value-added products, while lacking desirable piezoelectrics for high chemical energy production. Here, two polar layered bismuth-rich oxyhalides Bi₄O₅X₂ (XBr, I) thin nanosheets (≈4 nm) are first exploited as efficient piezocatalysts to be capable of dissociating pure water. The unique asymmetrical layered structures of Bi₄O₅X₂ (XBr, I) composed of the interleaved [Bi₄O₅]²⁺ layer and double X⁻ ions slabs along the [1 0 1_] orientation cause large intrinsic dipole moment, excellent piezoelectricity and easy deformation. Without any cocatalyst and sacrificial agent, Bi₄O₅Br₂ and Bi₄O₅I₂ thin nanosheets display remarkable piezocatalytic H₂ production rate of 1149.0 and 764.5 µmol g⁻¹ h⁻¹, respectively, standing among the best piezocatalysts, accompanied by H₂O₂ and hydroxyl radicals (·OH) as oxidative products. The smaller radius and higher electronegativity of interleaved Br than I cause a more strongly polar crystal structure in Bi₄O₅Br₂, contributing to the higher piezocatalytic activity compared to Bi₄O₅I₂. This study broadens the scope of piezoelectric materials applied to sustainable energy catalysis by efficiently converting mechanical energy and illustrates the importance of crystal configuration and composition in fabricating efficient piezocatalytic systems.