Simulation-Guided Design of Bamboo Leaf-Derived Carbon-Based High-Efficiency Evaporator for Solar-Driven Interface Water Evaporation

Solar interface water evaporation has been demonstrated to be an advanced method for freshwater production with high solar energy utilization.The development of evaporators with lower cost and higher efficiency is a key challenge in the manufacture of practical solar interface water evaporation devices.Herein,a bamboo leaf-derived carbon-based evaporator is designed based on the light trace simulation.And then,it is manufactured by vertical arrangement and carbonization of bamboo leaves and subsequent polyacrylamide modification.The vertically arranged carbon structure can extend the light path and increase the light-absorbing area,thus achieving excellent light absorption.Furthermore,the continuous distribution of polyacrylamide hydrogel between these vertical carbons can support high-speed water delivery and shorten the evaporation path.Therefore,this evaporator exhibits an ultrahigh average light absorption rate of~96.1%,a good water evaporation rate of 1.75 kg m^(-2) h^(-1),and an excellent solar-to-vapor efficiency of 91.9%under one sun irradiation.Furthermore,the device based on this evaporator can effectively achieve seawater desalination,heavy metal ion removal,and dye separation while completing water evaporation.And this device is highly available for actual outdoor applications and repeated recycling.

Development of wet adhesion of honeybee arolium incorporated polygonal structure with three-phase composite interfaces

Inspired by the dynamic wet adhesive systems in nature,various artificial adhesive surfaces have been developed but still face different challenges.Crucially,the theoretical mechanics of wet adhesives has never been sufficiently revealed.Here,we develop a novel adhesive mechanism for governing wet adhesion and investigate the biological models of honeybee arolium for reproducing the natural wet adhesive systems.Micro-nano structures of honeybee arolium and arolium-prints were observed by Cryogenic scanning electron microscopy(Cryo-SEM),and the air pockets were found in the contact interface notably.Subsequently,the adhesive models with a three-phase composite interface(including air pockets,liquid secretion,and hexagonal frames of arolium),were formed to analyze the wet adhesion of honeybee arolium.The results of theoretical calculations and experiments indicated an enhanced adhesive mechanism of the honeybee by liquid self-sucking effects and air-embolism effects.Under these effects,normal and shear adhesion can be adjusted by controlling the proportion of liquid secretion and air pockets in the contact zone.Notably,the air-embolism effects contribute to the optimal coupling of smaller normal adhesion with greater shear adhesion,which is beneficial for the high stride frequency of honeybees.These works can provide a fresh perspective on the development of bio-inspired wet adhesive surfaces.

Dynamic Vertical Climbing Mechanism of Chinese Dragon-Li Cats Based on the Linear Inverted Pendulum Model

Humans have long desired but never achieved the capacity to climb walls.The fundamental reason is that human hands and feet cannot climb vertical walls like geckos and bees.Animals lacking an adhesive structure can use the body’s dynamic effect to climb walls.Here we investigated the dynamic wall climbing behavior of individuals who cannot remain stationary on the vertical wall.Taking the domestic cat as the experimental object,we constructed an experimental platform as the obstacle for the cat to climb the wall.Our research indicated that domestic cats must meet the following physical conditions to do dynamic vertical wall climbing:vertical obstacles must have nonvertical surfaces,a horizontal run-up,and contact with nonvertical surfaces before the vertical speed reduces to zero.Here we proposed a dynamic vertical wall climbing model with three contact states based on an investigation of domestic cats’dynamic wall climbing behavior and the LIP model.The motion range of the LIP model’s generalized angular coordinates varies depending on the contact state.The horizontal run-up action can improve the jumping height and obtain horizontal speed.When making contact with the vertical surface of the obstacle,the motion inertia in the horizontal direction can produce a reaction force on the contact surface,which can compensate for the influence of some gravity.This alternating contact strategy lets cats switch different initial and end contact angles.This investigation clarifies the essential process underlying animals’dynamic vertical wall climbing and establishes the theoretical foundation for the legged robot to do dynamic vertical wall climbing.