Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their moveme...Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and search.This article mainly reviews the research progress of biomimetic water strider robots.First,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are summarized.The basic equations of water strider movement are then described.Next,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure dominance.Based on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is discussed.This article provides new insights for the design of biomimetic water strider robots.展开更多
Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical...Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical research into water striders. Morphological and behavioral traits of water striders are summarized and discussed from biomechanical perspectives, along with comparative study. This integrated review also highlights potential directions for studies on water-walking arthropods,which might inspire future biological and biomechanical research.展开更多
It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively ...It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.展开更多
The design of most water strider robots follows the principle that all supporting legs are in a plane,and each supporting leg bears a certain load and the water strider robot can float on the water.To meet this princi...The design of most water strider robots follows the principle that all supporting legs are in a plane,and each supporting leg bears a certain load and the water strider robot can float on the water.To meet this principle,the number of supporting legs and the spacing between each supporting legs of the water strider robot must be increased,which makes the shape of water strider robots look like octopus.This study proposed a novel water strider robot named 5S-robot,which used five new umbrella-type footpads and a centrifugal pump-based actuating mechanism.Motion analysis model and force analysis model of 5S-robot were built.The general consistency between the results of motion experiments and those of numerical simulation verified the former models.For this 5S-robot,the maximum load of 110.5 g and forward speed of 207.1 mm s^(-1)and rotational speed of 1.22 rad s^(-1)were measured,respectively.展开更多
Computer-aided diagnosis(CAD)models exploit artificial intelligence(AI)for chest X-ray(CXR)examination to identify the presence of tuberculosis(TB)and can improve the feasibility and performance of CXR for TB screenin...Computer-aided diagnosis(CAD)models exploit artificial intelligence(AI)for chest X-ray(CXR)examination to identify the presence of tuberculosis(TB)and can improve the feasibility and performance of CXR for TB screening and triage.At the same time,CXR interpretation is a time-consuming and subjective process.Furthermore,high resemblance among the radiological patterns of TB and other lung diseases can result in misdiagnosis.Therefore,computer-aided diagnosis(CAD)models using machine learning(ML)and deep learning(DL)can be designed for screening TB accurately.With this motivation,this article develops a Water Strider Optimization with Deep Transfer Learning Enabled Tuberculosis Classification(WSODTL-TBC)model on Chest X-rays(CXR).The presented WSODTL-TBC model aims to detect and classify TB on CXR images.Primarily,the WSODTL-TBC model undergoes image filtering techniques to discard the noise content and U-Net-based image segmentation.Besides,a pre-trained residual network with a two-dimensional convolutional neural network(2D-CNN)model is applied to extract feature vectors.In addition,the WSO algorithm with long short-term memory(LSTM)model was employed for identifying and classifying TB,where the WSO algorithm is applied as a hyperparameter optimizer of the LSTM methodology,showing the novelty of the work.The performance validation of the presented WSODTL-TBC model is carried out on the benchmark dataset,and the outcomes were investigated in many aspects.The experimental development pointed out the betterment of the WSODTL-TBC model over existing algorithms.展开更多
Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierar...Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierarchical structure of the legs,which are covered with a large number of inclined setae with fine nanogrooves inducing water resistance.This inspires us to fabricate special water-repellent structure on functional surfaces through the cooperation between the surface treatment and the surface micro-and nanostructures,which may bring great advantages in a wide variety of applications.In this paper we present a procedure for fabricating biomimetic water strider legs covered with setae using Polycarbonate Track-Etched(PCTE)membranes as templates.By choosing appropriate membrane lengths,diameters,pitches and densities of the setae,the biomimetic legs can be fabricated conveniently and at a low cost.Furthermore we investigated the relationship between stiffness of the molding materials,high aspect ratio and density,which affect the fidelity of fabrication and self adhesion,to optimize the stability of setae.The knowledge we gained from this study will offer important insights into the biomimetic design and fabrication of water strider setae.展开更多
Water strider Aquarius paludum （Fabricius） is a cosmopolitan species colonizes mainly freshwater but occasionally brackish habitats throughout the Palearctic and Oriental regions. Water strider Gerris latiabdominis ...Water strider Aquarius paludum （Fabricius） is a cosmopolitan species colonizes mainly freshwater but occasionally brackish habitats throughout the Palearctic and Oriental regions. Water strider Gerris latiabdominis （Miyamoto） is a common species in Japan lives in temporary habitats as freshwater paddy fields. These two species often occur syntopically. We investigated differences in the developmental response to brackish water during embryonic and larval stages between the two species. Eggs were exposed to 0-1.8% NaC1 solutions within 24 h of oviposition. Larvae of G. latiabdominis were exposed to salinities of 0, 0.5%, and 0.9% from the first instar until adult emergence. Limits of NaC1 concentration for hatching were 1.3% and 1.0% for A. paludum and G. latiabdominis, respectively. The hatching rate of G. latiabdominis was lower than that ofA. paludum at salinities 〉0.9%. The period of embryonic development of G. latiabdominis was more prolonged than that ofA. paludum at a given salinity. Although the salinity tolerance of G. latiabdominis was lower than that ofA. paludum, our results suggest G. latiabdominis has the physiological capacity to expand into brackish waters. High and low salinity tolerances of A. paludum and G. latiabdominis, respectively, reflect the relatively wide range of habitat salinities utilized by A. paludum and the relatively restricted habitats preferred by G. latiabdominis. The high salinity tolerance ofA. paludum could be an important factor contributing to their cosmopolitan distribution because high tolerance to salinity means the possibility of them to be dispersed via ocean or sea to other continents and islands.展开更多
基金supported in part by the National Natural Science Foundation of China(No.11972170).
文摘Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low noise.Researchers have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and search.This article mainly reviews the research progress of biomimetic water strider robots.First,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are summarized.The basic equations of water strider movement are then described.Next,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure dominance.Based on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is discussed.This article provides new insights for the design of biomimetic water strider robots.
基金the National Natural Science Foundation of China(51425502)。
文摘Water striders have intrigued researchers for centuries from the viewpoints of biology to biomechanics. In this review, we introduce the basic theories and techniques of physics and force measurement for biomechanical research into water striders. Morphological and behavioral traits of water striders are summarized and discussed from biomechanical perspectives, along with comparative study. This integrated review also highlights potential directions for studies on water-walking arthropods,which might inspire future biological and biomechanical research.
文摘It is known that contact lines keep relatively still on solids until static contact angles exceed an interval of hysteresis of static contact angle (HSCA), and contact angles keep changing as contact lines relatively slide on the solid. Here, the effects of HSCA and boundary slip were first distinguished on the micro-curvature force (MCF) on the seta. Hence, the total MCF is partitioned into static and dynamic MCFs correspondingly. The static MCF was found proportional to the HSCA and related with the asymmetry of the micro-meniscus near the seta. The dynamic MCF, exerting on the relatively sliding contact line, is aroused by the boundary slip. Based on the Blake-Haynes mechanism, the dynamic MCF was proved important for water walking insects with legs slower than the minimum wave speed . As insects brush the water by laterally swinging legs backwards, setae on the front side of the leg are pulled and the ones on the back side are pushed to cooperatively propel bodies forward. If they pierce the water surface by vertically swinging legs downwards, setae on the upside of the legs are pulled, and the ones on the downside are pushed to cooperatively obtain a jumping force. Based on the dependency between the slip length and shear rate, the dynamic MCF was found correlated with the leg speed U, as , where and are determined by the dimple depth. Discrete points on this curve could give fitted relations as (Suter et al., J. Exp. Biol. 200, 2523-2538, 1997). Finally, the axial torque on the inclined and partially submerged seta was found determined by the surface tension, contact angle, HSCA, seta width, and tilt angle. The torque direction coincides with the orientation of the spiral grooves of the seta, which encourages us to surmise it is a mechanical incentive for the formation of the spiral morphology of the setae of water striders.
基金financially supported by National Natural Science Foundation of China(No.51975550)Zhejiang Provincial Natural Science Foundation of China(No.LY21E050007)。
文摘The design of most water strider robots follows the principle that all supporting legs are in a plane,and each supporting leg bears a certain load and the water strider robot can float on the water.To meet this principle,the number of supporting legs and the spacing between each supporting legs of the water strider robot must be increased,which makes the shape of water strider robots look like octopus.This study proposed a novel water strider robot named 5S-robot,which used five new umbrella-type footpads and a centrifugal pump-based actuating mechanism.Motion analysis model and force analysis model of 5S-robot were built.The general consistency between the results of motion experiments and those of numerical simulation verified the former models.For this 5S-robot,the maximum load of 110.5 g and forward speed of 207.1 mm s^(-1)and rotational speed of 1.22 rad s^(-1)were measured,respectively.
文摘Computer-aided diagnosis(CAD)models exploit artificial intelligence(AI)for chest X-ray(CXR)examination to identify the presence of tuberculosis(TB)and can improve the feasibility and performance of CXR for TB screening and triage.At the same time,CXR interpretation is a time-consuming and subjective process.Furthermore,high resemblance among the radiological patterns of TB and other lung diseases can result in misdiagnosis.Therefore,computer-aided diagnosis(CAD)models using machine learning(ML)and deep learning(DL)can be designed for screening TB accurately.With this motivation,this article develops a Water Strider Optimization with Deep Transfer Learning Enabled Tuberculosis Classification(WSODTL-TBC)model on Chest X-rays(CXR).The presented WSODTL-TBC model aims to detect and classify TB on CXR images.Primarily,the WSODTL-TBC model undergoes image filtering techniques to discard the noise content and U-Net-based image segmentation.Besides,a pre-trained residual network with a two-dimensional convolutional neural network(2D-CNN)model is applied to extract feature vectors.In addition,the WSO algorithm with long short-term memory(LSTM)model was employed for identifying and classifying TB,where the WSO algorithm is applied as a hyperparameter optimizer of the LSTM methodology,showing the novelty of the work.The performance validation of the presented WSODTL-TBC model is carried out on the benchmark dataset,and the outcomes were investigated in many aspects.The experimental development pointed out the betterment of the WSODTL-TBC model over existing algorithms.
文摘Water striders have remarkable water-repellent legs that enable them to stand effortlessly and move quickly on water.Fluid physics indicates this feature is due to a surface-tension effect caused by the special hierarchical structure of the legs,which are covered with a large number of inclined setae with fine nanogrooves inducing water resistance.This inspires us to fabricate special water-repellent structure on functional surfaces through the cooperation between the surface treatment and the surface micro-and nanostructures,which may bring great advantages in a wide variety of applications.In this paper we present a procedure for fabricating biomimetic water strider legs covered with setae using Polycarbonate Track-Etched(PCTE)membranes as templates.By choosing appropriate membrane lengths,diameters,pitches and densities of the setae,the biomimetic legs can be fabricated conveniently and at a low cost.Furthermore we investigated the relationship between stiffness of the molding materials,high aspect ratio and density,which affect the fidelity of fabrication and self adhesion,to optimize the stability of setae.The knowledge we gained from this study will offer important insights into the biomimetic design and fabrication of water strider setae.
文摘Water strider Aquarius paludum （Fabricius） is a cosmopolitan species colonizes mainly freshwater but occasionally brackish habitats throughout the Palearctic and Oriental regions. Water strider Gerris latiabdominis （Miyamoto） is a common species in Japan lives in temporary habitats as freshwater paddy fields. These two species often occur syntopically. We investigated differences in the developmental response to brackish water during embryonic and larval stages between the two species. Eggs were exposed to 0-1.8% NaC1 solutions within 24 h of oviposition. Larvae of G. latiabdominis were exposed to salinities of 0, 0.5%, and 0.9% from the first instar until adult emergence. Limits of NaC1 concentration for hatching were 1.3% and 1.0% for A. paludum and G. latiabdominis, respectively. The hatching rate of G. latiabdominis was lower than that ofA. paludum at salinities 〉0.9%. The period of embryonic development of G. latiabdominis was more prolonged than that ofA. paludum at a given salinity. Although the salinity tolerance of G. latiabdominis was lower than that ofA. paludum, our results suggest G. latiabdominis has the physiological capacity to expand into brackish waters. High and low salinity tolerances of A. paludum and G. latiabdominis, respectively, reflect the relatively wide range of habitat salinities utilized by A. paludum and the relatively restricted habitats preferred by G. latiabdominis. The high salinity tolerance ofA. paludum could be an important factor contributing to their cosmopolitan distribution because high tolerance to salinity means the possibility of them to be dispersed via ocean or sea to other continents and islands.
