Technological advancements in unmanned aerial vehicles(UAVs)have revolutionized various industries,enabling the widespread adoption of UAV-based solutions.In engineering management,UAV-based inspection has emerged as ...Technological advancements in unmanned aerial vehicles(UAVs)have revolutionized various industries,enabling the widespread adoption of UAV-based solutions.In engineering management,UAV-based inspection has emerged as a highly efficient method for identifying hidden risks in high-risk construction environments,surpassing traditional inspection techniques.Building on this foundation,this paper delves into the optimization of UAV inspection routing and scheduling,addressing the complexity introduced by factors such as no-fly zones,monitoring-interval time windows,and multiple monitoring rounds.To tackle this challenging problem,we propose a mixed-integer linear programming(MILP)model that optimizes inspection task assignments,monitoring sequence schedules,and charging decisions.The comprehensive consideration of these factors differentiates our problem from conventional vehicle routing problem(VRP),leading to a mathematically intractable model for commercial solvers in the case of large-scale instances.To overcome this limitation,we design a tailored variable neighborhood search(VNS)metaheuristic,customizing the algorithm to efficiently solve our model.Extensive numerical experiments are conducted to validate the efficacy of our proposed algorithm,demonstrating its scalability for both large-scale and real-scale instances.Sensitivity experiments and a case study based on an actual engineering project are also conducted,providing valuable insights for engineering managers to enhance inspection work efficiency.展开更多
Rice‒rape,rice‒wheat and rice‒garlic rotations are common cropping systems in Southwest China,and they have played a significant role in ensuring ecological and economic benefits(EB)and addressing the challenges of Ch...Rice‒rape,rice‒wheat and rice‒garlic rotations are common cropping systems in Southwest China,and they have played a significant role in ensuring ecological and economic benefits(EB)and addressing the challenges of China’s food security in the region.However,the crop yields in these rotation systems are 1.25‒14.73%lower in this region than the national averages.Intelligent decision-making with machine learning can analyze the key factors for obtaining better benefits,but it has rarely been used to enhance the probability of obtaining such benefits from rotations in Southwest China.Thus,we used a data-intensive approach to construct an intelligent decision‒making system with machine learning to provide strategies for improving the benefits of rice-rape,rice-wheat,and rice-garlic rotations in Southwest China.The results show that raising the yield and partial fertilizer productivity(PFP)by increasing seed input under high fertilizer application provided the optimal benefits with a 10%probability in the rice-garlic system.Obtaining high yields and greenhouse gas(GHG)emissions by increasing the N application and reducing the K application provided suboptimal benefits with an 8%probability in the rice-rape system.Reducing N and P to enhance PFP and yield provided optimal benefits with the lowest probability(8%)in the rice‒wheat system.Based on the predictive analysis of a random forest model,the optimal benefits were obtained with fertilization regimes by reducing N by 25%and increasing P and K by 8 and 74%,respectively,in the rice-garlic system,reducing N and K by 54 and by 36%,respectively,and increasing P by 38%in rice-rape system,and reducing N by 4%and increasing P and K by 65 and 23%in rice-wheat system.These strategies could be further optimized by 17‒34%for different benefits,and all of these measures can improve the effectiveness of the crop rotation systems to varying degrees.Overall,these findings provide insights into optimal agricultural inputs for higher benefits through an intelligent decision-making system with machine learning analysis in the rice-rape,rice‒wheat,and rice-garlic systems.展开更多
Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics device...Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.展开更多
Direct methanol fuel cells （DMFCs） are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts...Direct methanol fuel cells （DMFCs） are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts for both cathode and anode face several problems which hinder the commercialization of DMFCs.In this review, we mainly focus on anode catalysts of DMFCs. The process and mechanism of methanolelectrooxidation on Pt and Pt-based catalysts in acidic medium have been introduced. The influences ofsize effect and morphology on electrocatalytic activity are discussed though whether there is a size effectin MOP, catalyst is under debate. Besides, the non Pt catalysts are also listed to emphasize though Pt isstill deemed as the indispensable element in anode catalyst of DMFCs in acidic medium. Different cata-lyst systems are compared to illustrate the level of research at present. ome debates need to be verifiedwith experimental evidences.展开更多
Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a h...Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure(ZSM-5/SiC).Characterizations of the ZSM-5/SiC by scanning electron microscopy,N2 sorption,and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity.Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst,which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate,a model molecule for biofuel.In comparison to the powder Pd@ZSM-5,the Pd@ZSM-5/SiC monolith catalyst shows more efficiency,which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure.The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.展开更多
Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplantin...Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.展开更多
The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing ...The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing the hybrid structure with Cu_(2)S nanoparticles on amorphous CuSx matrix(Cu_(2)S/CuSx).In the photocatalytic CO_(2) reduction under visible light irradiation,the Cu_(2)S/CuSx exhibited a CO production rate at 4.0μmol h-1 that is 12-fold higher than that of the general Cu_(2)S catalyst.Further characterizations reveal that the Cu_(2)S/CuSx has two reaction systems that realize the biomimetic catalysis,involving in the light reaction on the Cu_(2)S nanoparticle-CuSx matrix heterojunctions for proton/electron production,and the dark reaction on the defect-rich CuSx for CO_(2) reduction.The CuSx matrix could efficiently activate CO_(2) and stabilize the split hydrogen species to hinder undesired hydrogen evolution reaction,which benefits the proton-electron transfer to reduce CO_(2),a key step for bridging the two reaction systems.展开更多
This paper presents that a serpentine curve-based controller can solve locomotion control problems for articulated space robots with extensive flight phases,such as obstacle avoidance during free floating or attitude ...This paper presents that a serpentine curve-based controller can solve locomotion control problems for articulated space robots with extensive flight phases,such as obstacle avoidance during free floating or attitude adjustment before landing.The proposed algorithm achieves articulated robots to use closed paths in the joint space to accomplish the above tasks.Flying snakes,which can shuttle through gaps and adjust their landing posture by swinging their body during gliding in jungle environments,inspired the design of two maneuvers.The first maneuver generates a rotation of the system by varying the moment of inertia between the joints of the robot,with the magnitude of the net rotation depending on the controller parameters.This maneuver can be repeated to allow the robot to reach arbitrary reorientation.The second maneuver involves periodic undulations,allowing the robot to avoid collisions when the trajectory of the global Center of Mass(CM)passes through the obstacle.Both maneuvers are based on the improved serpenoid curve,which can adapt to redundant systems consisting of different numbers of modules.Finally,the simulation illustrates that combining the two maneuvers can help a free-floating chain-type robot traverse complex environments.Our proposed algorithm can be used with similar articulated robot models.展开更多
Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)struc...Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)structure with average grain size of 0.83μm was achieved with the help of sharply reduced heat input and holding time at elevated temperature.The optimized UFG structure enabled a superior combination of strength and ductility with high ultimate tensile strength and elongation of 273.17 MPa and 15.39%.Specifically,grain refinement strengthening and decentralized θ(Al_(2)Cu)phase in the sample subjected to SFSP made great contributions to the enhanced strength.In addition,the decrease in residual stresses and removal of pores substantially enhance the ductility.High rates of cooling and low temperature cycling,which are facilitated by the water-cooling environment throughout the machining process,are vital in obtaining superior microstructures.This work provides a new method for developing a uniform and UFG structure with excellent mechanical properties.展开更多
Peanut(Arachis hypogaea L.)is an important leguminous oil and economic crop that produces flowers aboveground and fruits belowground.Subterranean fruit-pod development,which significantly affects peanut production,inv...Peanut(Arachis hypogaea L.)is an important leguminous oil and economic crop that produces flowers aboveground and fruits belowground.Subterranean fruit-pod development,which significantly affects peanut production,involves complex molecular mechanisms that likely require the coordinated regulation of multiple genes in different tissues.To investigate the molecular mechanisms that underlie peanut fruitpod development,we characterized the anatomical features of early fruit-pod development and integrated single-nucleus RNA-sequencing(snRNA-seq)and single-nucleus assay for transposase-accessible chromatin with sequencing(snATAC-seq)data at the single-cell level.We identified distinct cell types,such as meristem,embryo,vascular tissue,cuticular layer,and stele cells within the shell wall.These specific cell types were used to examine potential molecular changes unique to each cell type during pivotal stages of fruit-pod development.snRNA-seq analyses of differentially expressed genes revealed cell-type-specific insights that were not previously obtainable from transcriptome analyses of bulk RNA.For instance,we identified MADS-box genes that contributes to the formation of parenchyma cells and gravity-related genes that are present in the vascular cells,indicating an essential role for the vascular cells in peg gravitropism.Overall,our single-nucleus analysis provides comprehensive and novel information on specific cell types,gene expression,and chromatin accessibility during the early stages of fruit-pod development.This information will enhance our understanding of the mechanisms that underlie fruit-pod development in peanut and contribute to efforts aimed at improving peanut production.展开更多
As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as h...As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as higher real-time performance,enhanced interactivity,more realistic 3D visualization effect and improved user interface.This paper aims to present a comprehensive and upto-date 3D Web GIS for Emergency Response using the current vue.js web application framework and the well-known Cesium APl,taking landslide disaster as an example.Building upon recent advances in WebGL technology,we developed a suite of enhanced 3D spatial analysis functions,including interactive route planning,instant text/image/video messaging being incorporated into both 3D WebGL page and mobile GIS applications,and progressive 3D construction and AR visualization using LiDAR and camera over local emergency network or internet.Moreover,professional functions such as landslide susceptibility mapping,landslide monitoring,spatial temporal contingency plan management,landslide information management,personnel and equipment management,and communication are all implemented and integrated in the 3D GIS system.Most of the functions of the system are implemented using open-source projects,which is beneficial to the development of the 3D GIS research community.展开更多
Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscos...Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscosity values,which cannot meet the requirements of practical industrial applications.Herein,we demonstrate a generalizable and simple strategy to prepare type III PLs with low viscosity based on the rule of“like dissolves like”.Specifically,the monoglycidyl ether terminated polydimethylsiloxane(denoted by E-PDMS)is attached to the surface of Universitetet i Oslo(UiO)-66-NH_(2)via covalent linkage,constructing the pore generator(UiO-66-NH_(2)-E-PDMS,denoted by P-UiO-66).Then,P-UiO-66 is dispersed into different types and amounts of sterically hindered solvents(PDMS400 or PDMS6000),obtaining a series of type III PLs(denoted by P-UiO-66-PLs)with permanent cavities and low viscosities.The gas sorption-desorption test shows that P-UiO-66-PLs have an enormous potential for CO_(2)/N_(2) selective separation.Besides,the porosity of P-UiO-66-PLs and the CO_(2)sorption mechanism are demonstrated by molecular simulation.Furthermore,the generality of the synthesis strategy is confirmed by the successful construction of PLs using two other amino-metal-organic frameworks(MOFs)(MIL-53(Al)-NH_(2)and MIL-88B(Fe)-NH_(2)).Importantly,it’s worth noting that the strategy based on the rule of“like dissolves like”sheds light on the preparation of other types of PLs for task-specific applications.展开更多
The biomedical literature is a vast and invaluable resource for biomedical research.Integrating knowledge from the literature with biomedical data can help biological studies and the clinical decision-making process.E...The biomedical literature is a vast and invaluable resource for biomedical research.Integrating knowledge from the literature with biomedical data can help biological studies and the clinical decision-making process.Efforts have been made to gather information from the biomedical literature and create biomedical knowledge bases,such as KEGG and Reactome.However,manual curation remains the primary method to retrieve accurate biomedical entities and relationships.Manual curation becomes increasingly challenging and costly as the volume of biomedical publications quickly grows.Fortunately,recent advancements in Artificial Intelligence(AI)technologies offer the potential to automate the process of curating,updating,and integrating knowledge from the literature.Herein,we highlight the AI capabilities to aid in mining knowledge and building the knowledge base from the biomedical literature.展开更多
Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and in...Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and infrastructure construction. The development route, mechanisms design, control methods and mobile manipulating approaches of the quadruped robots are surveyed in this article. Firstly, the development route of the quadruped robot is combed, as the references of the forecast of the future work on quadruped robots. Then the bionic structure and the motion control method of the quadruped robot is summarized, the advantages and disadvantages are analyzed in aspects of gait switching, terrain adaption and disturbance resistance. Subsequently, aiming at the mobile manipulation of the quadruped robot, the representative leg-arm collaborative robots and the multi-task-oriented Whole-body Control (WBC) methods are introduced. Finally, the summary and future work of the quadruped robots is given.展开更多
General,high-precision theoretical modeling method is not well developed in the field of soft robotics,which holds back motion control and practical application of soft robots.The concept of modularization brings nove...General,high-precision theoretical modeling method is not well developed in the field of soft robotics,which holds back motion control and practical application of soft robots.The concept of modularization brings novel structure,novel locomotion patterns as well as novel control method for soft robots.This paper presents the concept of hierarchical control method for modular soft robot system and a H-configuration pneumatic modular soft robot is designed as the control object.The H-configuration modular soft robot is composed of two basic motion units that take worm-like locomotion principle.The locomotion principle of the basic motion unit is analyzed and the actuation sequence is optimized by evolution strategy in VOXCAD simulation software.The differential drive method is applied to the H-configuration modular soft robot with multi motion modes and vision sensor is used to control the motion mode of the robot.The H-configuration modular soft robot and the basic motion unit are assembled by a cubic soft module made of silicone rubber.Also,connection mechanism is designed to ensure that the soft modules can be assembled in any direction and posture.Experiments are conducted to verify the effect of the hierarchical control method of the modular soft robots.展开更多
Simultaneous Localization and Mapping(SLAM)has been widely used in emergency response,self-driving and city-scale 3D mapping and navigation.Recent deep-learning based feature point extractors have demonstrated superio...Simultaneous Localization and Mapping(SLAM)has been widely used in emergency response,self-driving and city-scale 3D mapping and navigation.Recent deep-learning based feature point extractors have demonstrated superior performance in dealing with the complex environmental challenges(e.g.extreme lighting)while the traditional extractors are struggling.In this paper,we have successfully improved the robustness and accuracy of a monocular visual SLAM system under various complex scenes by adding a deep learning based visual localization thread as an augmentation to the visual SLAM framework.In this thread,our feature extractor with an efficient lightweight deep neural network is used for absolute pose and scale estimation in real time using the highly accurate georeferenced prior map database at 20cm geometric accuracy created by our in-house and low-cost LiDAR and camera integrated device.The closed-loop error provided by our SLAM system with and without this enhancement is 1.03m and 18.28m respectively.The scale estimation of the monocular visual SLAM is also significantly improved(0.01 versus 0.98).In addition,a novel camera-LiDAR calibration workflow is also provided for large-scale 3D mapping.This paper demonstrates the application and research potential of deep-learning based vision SLAM with image and LiDAR sensors.展开更多
基金supported by the National Natural Science Foundation of China(72201229,72025103,72394360,72394362,72361137001,72071173,and 71831008).
文摘Technological advancements in unmanned aerial vehicles(UAVs)have revolutionized various industries,enabling the widespread adoption of UAV-based solutions.In engineering management,UAV-based inspection has emerged as a highly efficient method for identifying hidden risks in high-risk construction environments,surpassing traditional inspection techniques.Building on this foundation,this paper delves into the optimization of UAV inspection routing and scheduling,addressing the complexity introduced by factors such as no-fly zones,monitoring-interval time windows,and multiple monitoring rounds.To tackle this challenging problem,we propose a mixed-integer linear programming(MILP)model that optimizes inspection task assignments,monitoring sequence schedules,and charging decisions.The comprehensive consideration of these factors differentiates our problem from conventional vehicle routing problem(VRP),leading to a mathematically intractable model for commercial solvers in the case of large-scale instances.To overcome this limitation,we design a tailored variable neighborhood search(VNS)metaheuristic,customizing the algorithm to efficiently solve our model.Extensive numerical experiments are conducted to validate the efficacy of our proposed algorithm,demonstrating its scalability for both large-scale and real-scale instances.Sensitivity experiments and a case study based on an actual engineering project are also conducted,providing valuable insights for engineering managers to enhance inspection work efficiency.
基金supported by the China Postdoctoral Science Foundation(2022M722301)the Sichuan Province Innovative Talent Funding Project for Postdoctoral Fellows,China(BX202207)the Natural Science Foundation of Sichuan Province,China(2023NSFC0014 and 2024NSFSC1225).
文摘Rice‒rape,rice‒wheat and rice‒garlic rotations are common cropping systems in Southwest China,and they have played a significant role in ensuring ecological and economic benefits(EB)and addressing the challenges of China’s food security in the region.However,the crop yields in these rotation systems are 1.25‒14.73%lower in this region than the national averages.Intelligent decision-making with machine learning can analyze the key factors for obtaining better benefits,but it has rarely been used to enhance the probability of obtaining such benefits from rotations in Southwest China.Thus,we used a data-intensive approach to construct an intelligent decision‒making system with machine learning to provide strategies for improving the benefits of rice-rape,rice-wheat,and rice-garlic rotations in Southwest China.The results show that raising the yield and partial fertilizer productivity(PFP)by increasing seed input under high fertilizer application provided the optimal benefits with a 10%probability in the rice-garlic system.Obtaining high yields and greenhouse gas(GHG)emissions by increasing the N application and reducing the K application provided suboptimal benefits with an 8%probability in the rice-rape system.Reducing N and P to enhance PFP and yield provided optimal benefits with the lowest probability(8%)in the rice‒wheat system.Based on the predictive analysis of a random forest model,the optimal benefits were obtained with fertilization regimes by reducing N by 25%and increasing P and K by 8 and 74%,respectively,in the rice-garlic system,reducing N and K by 54 and by 36%,respectively,and increasing P by 38%in rice-rape system,and reducing N by 4%and increasing P and K by 65 and 23%in rice-wheat system.These strategies could be further optimized by 17‒34%for different benefits,and all of these measures can improve the effectiveness of the crop rotation systems to varying degrees.Overall,these findings provide insights into optimal agricultural inputs for higher benefits through an intelligent decision-making system with machine learning analysis in the rice-rape,rice‒wheat,and rice-garlic systems.
基金This work was supported by Taishan Scholars Project Special Funds(tsqn201812083)Natural Science Foundation of Shandong Province(ZR2019YQ20,2019JMRH0410,ZR2019BB001)the National Natural Science Foundation of China(51972147,51902132,52022037).
文摘Nanomaterials are known to exhibit a number of interesting physical and chemical properties for various applications,including energy conversion and storage,nanoscale electronics,sensors and actuators,photonics devices and even for biomedical purposes.In the past decade,laser as a synthetic technique and laser as a microfabrication technique facilitated nanomaterial preparation and nanostructure construction,including the laser processing-induced carbon and non-carbon nanomaterials,hierarchical structure construction,patterning,heteroatom doping,sputtering etching,and so on.The laser-induced nanomaterials and nanostructures have extended broad applications in electronic devices,such as light–thermal conversion,batteries,supercapacitors,sensor devices,actuators and electrocatalytic electrodes.Here,the recent developments in the laser synthesis of carbon-based and non-carbon-based nanomaterials are comprehensively summarized.An extensive overview on laser-enabled electronic devices for various applications is depicted.With the rapid progress made in the research on nanomaterial preparation through laser synthesis and laser microfabrication technologies,laser synthesis and microfabrication toward energy conversion and storage will undergo fast development.
基金supported by the National Natural Science Foundation of China (21633008,21673221)the Jilin Province Science and Technology Development Program (20160622037JC,20170203003SF,and 20170520150JH)+1 种基金the Hundred Talents Program of the Chinese Academy of Sciencesthe Recruitment Program of Foreign Experts (WQ20122200077)
文摘Direct methanol fuel cells （DMFCs） are very promising power source for stationary and portable miniatureelectric appliances due to its high efficiency and low emissions of pollutants. As the key material, cata-lysts for both cathode and anode face several problems which hinder the commercialization of DMFCs.In this review, we mainly focus on anode catalysts of DMFCs. The process and mechanism of methanolelectrooxidation on Pt and Pt-based catalysts in acidic medium have been introduced. The influences ofsize effect and morphology on electrocatalytic activity are discussed though whether there is a size effectin MOP, catalyst is under debate. Besides, the non Pt catalysts are also listed to emphasize though Pt isstill deemed as the indispensable element in anode catalyst of DMFCs in acidic medium. Different cata-lyst systems are compared to illustrate the level of research at present. ome debates need to be verifiedwith experimental evidences.
文摘Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure(ZSM-5/SiC).Characterizations of the ZSM-5/SiC by scanning electron microscopy,N2 sorption,and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity.Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst,which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate,a model molecule for biofuel.In comparison to the powder Pd@ZSM-5,the Pd@ZSM-5/SiC monolith catalyst shows more efficiency,which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure.The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.
基金supported by the National Key Research and Development Program of China(2017YFD0301701 and 2017YFD0301706)National Natural Science Foundation of China(31660369)。
文摘Machine transplanting and the application of slow-release nitrogen(N) fertilizer(SRNF) have played vital roles in the modernization of rice production. We aimed to determine the effects of potted-seedling transplanting—a new machine-transplanting method—and SRNF on hybrid rice yields. A 2-year splitplot experiment(2016–2017) was conducted in Meishan, Sichuan province, China, using two machinetransplanting methods(potted-seedling and blanket-seedling) and three N treatments. Total green leaf area, high-effective leaf area and its rate at heading, net photosynthetic rate of flag leaves 7 days after heading, glutamate synthase(GOGAT) and glutamine synthase(GS) activity after heading, dry matter production, and N accumulation at heading and maturity increased under the potted-seedling method or 70% SRNF as a base + 30% urea application at the panicle initiation stage(SBUP). Stem diameter and number of small and of all vascular bundles at the neck–panicle node in potted-seedling plants increased as a result of increasing numbers of effective panicles, secondary branches, and spikelets. In pottedseedling plants, treatment with SBUP increased the number of large and total vascular bundles at the panicle–neck internode and the number of differentiated and surviving secondary branches and spikelets and decreased the number of ineffective tillers and degenerated secondary branches and spikelets. We conclude that the potted-seedling machine transplanting method and SRNF combined with urea topdressing can strengthen the source–sink relationship in rice, resulting in higher yields.
基金supported by the National Key Research and Development Program of China(2018YFD1000806-01)the National Natural Science Foundation of China(21822203 and 21932006)+1 种基金the Natural Science Foundation of Zhejiang Province(LR18B030002)China Postdoctoral Science Foundation(2020M671020)。
文摘The performances of heterogeneous catalysts can be effectively improved by optimizing the catalysts via appropriate structure design.Herein,we show that the catalysis of cuprous sulfide can be boosted by constructing the hybrid structure with Cu_(2)S nanoparticles on amorphous CuSx matrix(Cu_(2)S/CuSx).In the photocatalytic CO_(2) reduction under visible light irradiation,the Cu_(2)S/CuSx exhibited a CO production rate at 4.0μmol h-1 that is 12-fold higher than that of the general Cu_(2)S catalyst.Further characterizations reveal that the Cu_(2)S/CuSx has two reaction systems that realize the biomimetic catalysis,involving in the light reaction on the Cu_(2)S nanoparticle-CuSx matrix heterojunctions for proton/electron production,and the dark reaction on the defect-rich CuSx for CO_(2) reduction.The CuSx matrix could efficiently activate CO_(2) and stabilize the split hydrogen species to hinder undesired hydrogen evolution reaction,which benefits the proton-electron transfer to reduce CO_(2),a key step for bridging the two reaction systems.
基金co-supported by the National Science Fund for Distinguished Young Scholars,China(No.52025054)the National Natural Science Foundation of China(No.61961015).
文摘This paper presents that a serpentine curve-based controller can solve locomotion control problems for articulated space robots with extensive flight phases,such as obstacle avoidance during free floating or attitude adjustment before landing.The proposed algorithm achieves articulated robots to use closed paths in the joint space to accomplish the above tasks.Flying snakes,which can shuttle through gaps and adjust their landing posture by swinging their body during gliding in jungle environments,inspired the design of two maneuvers.The first maneuver generates a rotation of the system by varying the moment of inertia between the joints of the robot,with the magnitude of the net rotation depending on the controller parameters.This maneuver can be repeated to allow the robot to reach arbitrary reorientation.The second maneuver involves periodic undulations,allowing the robot to avoid collisions when the trajectory of the global Center of Mass(CM)passes through the obstacle.Both maneuvers are based on the improved serpenoid curve,which can adapt to redundant systems consisting of different numbers of modules.Finally,the simulation illustrates that combining the two maneuvers can help a free-floating chain-type robot traverse complex environments.Our proposed algorithm can be used with similar articulated robot models.
文摘Submerged friction stir processing(SFSP)with flowing water was employed to alleviate the porosities and coarse-grained structure introduced by wire-arc manufacturing.As a result,uniform and ultrafine grained(UFG)structure with average grain size of 0.83μm was achieved with the help of sharply reduced heat input and holding time at elevated temperature.The optimized UFG structure enabled a superior combination of strength and ductility with high ultimate tensile strength and elongation of 273.17 MPa and 15.39%.Specifically,grain refinement strengthening and decentralized θ(Al_(2)Cu)phase in the sample subjected to SFSP made great contributions to the enhanced strength.In addition,the decrease in residual stresses and removal of pores substantially enhance the ductility.High rates of cooling and low temperature cycling,which are facilitated by the water-cooling environment throughout the machining process,are vital in obtaining superior microstructures.This work provides a new method for developing a uniform and UFG structure with excellent mechanical properties.
基金supported by grants from the Taishan Scholar Foundation of Shandong Province(tsqn202103161)the Natural Science Foundation of Shandong Province(ZR202103010405)+3 种基金the Key R&D Program of Shandong Province,China(ZR202211070163)the Foundation of President of the Peking University Institute of Advanced Agricultural Sciences(ZR202211070163)the Peanut Seed Industry Project in Shandong Province,China(2022LZGC007)to X.LIt was also funded by the National Natural Science Foundation of China(NSFC)Key Program(32230006)to X.W.D.
文摘Peanut(Arachis hypogaea L.)is an important leguminous oil and economic crop that produces flowers aboveground and fruits belowground.Subterranean fruit-pod development,which significantly affects peanut production,involves complex molecular mechanisms that likely require the coordinated regulation of multiple genes in different tissues.To investigate the molecular mechanisms that underlie peanut fruitpod development,we characterized the anatomical features of early fruit-pod development and integrated single-nucleus RNA-sequencing(snRNA-seq)and single-nucleus assay for transposase-accessible chromatin with sequencing(snATAC-seq)data at the single-cell level.We identified distinct cell types,such as meristem,embryo,vascular tissue,cuticular layer,and stele cells within the shell wall.These specific cell types were used to examine potential molecular changes unique to each cell type during pivotal stages of fruit-pod development.snRNA-seq analyses of differentially expressed genes revealed cell-type-specific insights that were not previously obtainable from transcriptome analyses of bulk RNA.For instance,we identified MADS-box genes that contributes to the formation of parenchyma cells and gravity-related genes that are present in the vascular cells,indicating an essential role for the vascular cells in peg gravitropism.Overall,our single-nucleus analysis provides comprehensive and novel information on specific cell types,gene expression,and chromatin accessibility during the early stages of fruit-pod development.This information will enhance our understanding of the mechanisms that underlie fruit-pod development in peanut and contribute to efforts aimed at improving peanut production.
基金supported by the National Key Research and Development Program of China under[Grant number 2019YFC1511304].
文摘As with the fast advances in the technologies of big Earth data and information communication,Web-based 3D GIS system has come a long way from a few years ago.These advances reflect in many aspects of 3D GIS such as higher real-time performance,enhanced interactivity,more realistic 3D visualization effect and improved user interface.This paper aims to present a comprehensive and upto-date 3D Web GIS for Emergency Response using the current vue.js web application framework and the well-known Cesium APl,taking landslide disaster as an example.Building upon recent advances in WebGL technology,we developed a suite of enhanced 3D spatial analysis functions,including interactive route planning,instant text/image/video messaging being incorporated into both 3D WebGL page and mobile GIS applications,and progressive 3D construction and AR visualization using LiDAR and camera over local emergency network or internet.Moreover,professional functions such as landslide susceptibility mapping,landslide monitoring,spatial temporal contingency plan management,landslide information management,personnel and equipment management,and communication are all implemented and integrated in the 3D GIS system.Most of the functions of the system are implemented using open-source projects,which is beneficial to the development of the 3D GIS research community.
基金This work is supported by the Aeronautical Science Foundation of China(No.2018ZF53065)the Key Project of Shaanxi Provincial Natural Science Foundation(No.2021JZ-09)+1 种基金the National Undergraduate Training Program for Innovation and Entrepreneurship(No.201910699113)the Shaanxi Province Science Foundation for Youths(No.2023-JC-QN-0146).
文摘Porous liquids(PLs),an emerging porous material with permanent cavities,have attracted extensive attention in recent years.However,the current construction methods are complicated and resulting PLs possess high viscosity values,which cannot meet the requirements of practical industrial applications.Herein,we demonstrate a generalizable and simple strategy to prepare type III PLs with low viscosity based on the rule of“like dissolves like”.Specifically,the monoglycidyl ether terminated polydimethylsiloxane(denoted by E-PDMS)is attached to the surface of Universitetet i Oslo(UiO)-66-NH_(2)via covalent linkage,constructing the pore generator(UiO-66-NH_(2)-E-PDMS,denoted by P-UiO-66).Then,P-UiO-66 is dispersed into different types and amounts of sterically hindered solvents(PDMS400 or PDMS6000),obtaining a series of type III PLs(denoted by P-UiO-66-PLs)with permanent cavities and low viscosities.The gas sorption-desorption test shows that P-UiO-66-PLs have an enormous potential for CO_(2)/N_(2) selective separation.Besides,the porosity of P-UiO-66-PLs and the CO_(2)sorption mechanism are demonstrated by molecular simulation.Furthermore,the generality of the synthesis strategy is confirmed by the successful construction of PLs using two other amino-metal-organic frameworks(MOFs)(MIL-53(Al)-NH_(2)and MIL-88B(Fe)-NH_(2)).Importantly,it’s worth noting that the strategy based on the rule of“like dissolves like”sheds light on the preparation of other types of PLs for task-specific applications.
基金the National Library of Medicine of the National Institute of Health(NIH)award number 5R01LM013392。
文摘The biomedical literature is a vast and invaluable resource for biomedical research.Integrating knowledge from the literature with biomedical data can help biological studies and the clinical decision-making process.Efforts have been made to gather information from the biomedical literature and create biomedical knowledge bases,such as KEGG and Reactome.However,manual curation remains the primary method to retrieve accurate biomedical entities and relationships.Manual curation becomes increasingly challenging and costly as the volume of biomedical publications quickly grows.Fortunately,recent advancements in Artificial Intelligence(AI)technologies offer the potential to automate the process of curating,updating,and integrating knowledge from the literature.Herein,we highlight the AI capabilities to aid in mining knowledge and building the knowledge base from the biomedical literature.
基金the National Natural Science Founda-tion of China(Grant No.91948201,Grant No.62073191,Grant No.61973135)the Shandong Key R&D Program(No.2019JZZY020317)the Fundamental Research Funds of Shandong University(Grant No.2019GN017).
文摘Some quadruped robots developed recently show better dynamic performance and environmental adaptability than ever, and have been preliminarily applied in the field of emergency disposal, military reconnaissance and infrastructure construction. The development route, mechanisms design, control methods and mobile manipulating approaches of the quadruped robots are surveyed in this article. Firstly, the development route of the quadruped robot is combed, as the references of the forecast of the future work on quadruped robots. Then the bionic structure and the motion control method of the quadruped robot is summarized, the advantages and disadvantages are analyzed in aspects of gait switching, terrain adaption and disturbance resistance. Subsequently, aiming at the mobile manipulation of the quadruped robot, the representative leg-arm collaborative robots and the multi-task-oriented Whole-body Control (WBC) methods are introduced. Finally, the summary and future work of the quadruped robots is given.
基金This work is supported by National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(Grant no.52025054)National Natural Science Foundation of China(Grant no.U1713201).
文摘General,high-precision theoretical modeling method is not well developed in the field of soft robotics,which holds back motion control and practical application of soft robots.The concept of modularization brings novel structure,novel locomotion patterns as well as novel control method for soft robots.This paper presents the concept of hierarchical control method for modular soft robot system and a H-configuration pneumatic modular soft robot is designed as the control object.The H-configuration modular soft robot is composed of two basic motion units that take worm-like locomotion principle.The locomotion principle of the basic motion unit is analyzed and the actuation sequence is optimized by evolution strategy in VOXCAD simulation software.The differential drive method is applied to the H-configuration modular soft robot with multi motion modes and vision sensor is used to control the motion mode of the robot.The H-configuration modular soft robot and the basic motion unit are assembled by a cubic soft module made of silicone rubber.Also,connection mechanism is designed to ensure that the soft modules can be assembled in any direction and posture.Experiments are conducted to verify the effect of the hierarchical control method of the modular soft robots.
基金supported by the National Key Research and Development Program of China under[Grant number 2019YFC1511304]supported by the Pilot Fund of Frontier Science and Disruptive Technology of Aerospace Information Research Institute,Chinese Academy of Sciences under[Grant number E0Z21101].
文摘Simultaneous Localization and Mapping(SLAM)has been widely used in emergency response,self-driving and city-scale 3D mapping and navigation.Recent deep-learning based feature point extractors have demonstrated superior performance in dealing with the complex environmental challenges(e.g.extreme lighting)while the traditional extractors are struggling.In this paper,we have successfully improved the robustness and accuracy of a monocular visual SLAM system under various complex scenes by adding a deep learning based visual localization thread as an augmentation to the visual SLAM framework.In this thread,our feature extractor with an efficient lightweight deep neural network is used for absolute pose and scale estimation in real time using the highly accurate georeferenced prior map database at 20cm geometric accuracy created by our in-house and low-cost LiDAR and camera integrated device.The closed-loop error provided by our SLAM system with and without this enhancement is 1.03m and 18.28m respectively.The scale estimation of the monocular visual SLAM is also significantly improved(0.01 versus 0.98).In addition,a novel camera-LiDAR calibration workflow is also provided for large-scale 3D mapping.This paper demonstrates the application and research potential of deep-learning based vision SLAM with image and LiDAR sensors.
