Predicting the future trajectories of multiple agents is essential for various applications in real life,such as surveillance systems,autonomous driving,and social robots.The trajectory prediction task is influenced b...Predicting the future trajectories of multiple agents is essential for various applications in real life,such as surveillance systems,autonomous driving,and social robots.The trajectory prediction task is influenced by many factors,including the individual historical trajectory,interactions between agents,and the fuzzy nature of the observed agents’motion.While existing methods have made great progress on the topic of trajectory prediction,they treat all the information uniformly,which limits the effectiveness of information utilization.To this end,in this paper,we propose and utilize a model-agnostic framework to regard all the information in a two-level hierarchical view.Particularly,the first-level view is the inter-trajectory view.In this level,we observe that the difficulty in predicting different trajectory samples varies.We define trajectory difficulty and train the proposed framework in an“easy-to-hard”schema.The second-level view is the intra-trajectory level.We find the influencing factors for a particular trajectory can be divided into two parts.The first part is global features,which keep stable within a trajectory,i.e.,the expected destination.The second part is local features,which change over time,i.e.,the current position.We believe that the two types of information should be handled in different ways.The hierarchical view is beneficial to take full advantage of the information in a fine-grained way.Experimental results validate the effectiveness of the proposed model-agnostic framework.展开更多
A notable retiring wave for lithium iron phosphate(LiFePO_(4),LFP)-based lithium-ion batteries(LIBs)is expected in the coming years,which urges the establishment of complete and eco-friendly recycling chains.Currently...A notable retiring wave for lithium iron phosphate(LiFePO_(4),LFP)-based lithium-ion batteries(LIBs)is expected in the coming years,which urges the establishment of complete and eco-friendly recycling chains.Currently,the industrial practice for these degraded LFP materials heavily relies on the hydrometallurgical strategies,which aim for the selective leaching of valuable Li element;this,however,leads to the accumulation of FePO_(4)by-product as a waste,which is neither economical nor sustainable.Considering the increasing demand on performance for next-generation LFP cathode materials,herein,we demonstrate a facile,green,and economic method to upcycle FePO_(4)residues from spent LIBs into high-performance LFP materials for direct reusages.The upcycling protocol involves simultaneous structural restoration of LFP lattices and hierarchical assembly of graphene-based conductive frameworks.As a result,the upcycled LFP cathode material delivers exceptional rate performance(discharge capacity of 125.6 mA h g^(-1)at 5 C or 93.6 mA h g^(-1)at 15 C)and cycling stability under high-rate conditions(capacity retention of 99.5%after 300 cycles at 1 C or 96.7%after 1000 cycles at 5 C).Moreover,the electrochemical performance is largely maintained at low temperatures.The upcycling strategy sheds light on the closed-loop development of LIB industry.展开更多
Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometal...Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometallic coordination polymer(OCP)induced strategy to construct hierarchical N-doped carbon framework with NiFe nanoparticles encapsulated inside(NxFe@N-C)as a highly active and stable OER catalyst.The synthesis of OCP precursor depends on the unique molecular structure of iminodiacetonitrile(IDAN),which can coordinate with metal ions to form Ni2Fe(CN)6 with prussian blue analogs(PBA)structure.Unlike previous PBA-induced methods,the thickness of the carbon layer covering the surface of the metal core can be well controlled during the pyrolysis through adjusting the amount of IDAN,which builds a wonderful bridge for investigating the relationship between carbon layer thickness and catalytic performance.Both the experimental characterizations and theoretical studies validate that a suitable carbon layers thickness leads to optimal OER activity and stability.By optimizing the structure and composition,the optimized Ni_(3)Fe@N-C with hierarchical framework exhibits the low overpotentials(260 mV at 10 mA cm^(-2);320 mV at 50 mA cm^(-2)),improved kinetics(79 mV dec^(-1)),and robust long-term stability,which exceeds those of benchmark RuO_(2).展开更多
The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is prop...The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs(NH-MOFs)with high crystallinity and excellent stability.This approach allows the morphology and porosity of MOFs to be fine tuned,thereby enabling the nanoscale crystal generation and a well-defined hierarchical system.The aqueous solution facilitates rapid nucleation kinetics,and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent(SDA)to guide the formation of hierarchical networks.The assynthesized NH-MOFs(NH-ZIF-67)were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of vip molecules,outperforming the parent microZIF-67.This study focuses on understanding the NH-MOF growth rules,which could allow tailor-designing NH-MOFs for various functions.展开更多
Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative partic...Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative particle swarm optimization(MHCHPSO)to optimize sensor deployment location and improve the coverage of WSN.MHCHPSO divides the population into three types topology:diversity topology for global exploration,fast convergence topology for local development,and collaboration topology for exploration and development.All topologies are optimized in parallel to overcome the precocious convergence of PSO.This paper compares with various heuristic algorithms at CEC 2013,CEC 2015,and CEC 2017.The experimental results show that MHCHPSO outperforms the comparison algorithms.In addition,MHCHPSO is applied to the WSN localization optimization,and the experimental results confirm the optimization ability of MHCHPSO in practical engineering problems.展开更多
Recently,learned heuristics have been widely applied to solve combinatorial optimization problems(e.g.,traveling salesman problem(TSP)).However,the scalability of these learning-based methods hinders the applications ...Recently,learned heuristics have been widely applied to solve combinatorial optimization problems(e.g.,traveling salesman problem(TSP)).However,the scalability of these learning-based methods hinders the applications in practical scenarios.Specifically,models pre-trained on the small-scale data generalize poorly to large-scale problems.Moreover,learning the heuristics directly for large-scale problems costs tremendous time and space.To extend the scalability of learned heuristics on TSP,we propose a Hierarchical neural framework for solving large-scale traveling salesman problems(HiTSPs)based on a divide-and-conquer strategy.In particular,the HiTSP framework first divides the large-scale problem into small-scale subproblems by node clustering.Each subproblem is conquered by a modified pointer network learned from reinforcement learning.The tour of the original TSP is constructed by linking solutions of subproblems and optimized by a novel segmented local search algorithm.Notably,the segmented local search algorithm leverages the node clustering information to prune many unnecessary operations and significantly reduces the complexity in theory.Extensive experiments show that HiTSP outperforms state-of-the-art learning-based methods and Google OR-Tools in large-scale cases.Moreover,compared to the best heuristic algorithms,HiTSP has a significant advantage in efficiency for large-scale TSP problems.展开更多
Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operato...Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operator training,etc.;thus,a hierarchical digital twin would be a comprehensive solution to that.In this study,a novel and general framework of the digital twin is proposed for operations in process industry.With the hierarchical structure,the framework can handle various tasks driven by different roles in process industry,including managers,engineers,and operators.To complete these tasks,the framework consists of three modules:OAS(Operation Analysis System),OMS(Operation Monitoring System),and OTS(Operator Training System).Each module focuses on one unique type of demand from the staff,as well as interactions among them enabling efficient data sharing.Based on the hierarchical framework,a digital twin system is applied for one complex industrial nitration process,which successfully enhances the operation efficiency and safety in several industrial scenarios with different demands.展开更多
The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions t...The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions to improve the process benefits and efficiency. Nevertheless, the performance assessment principally concentrates upon some parts of the entire system at present, for example the controller assessment. Although some researches focus on the whole process, they aim at discovering the relationships between profit, society, policies and so forth, instead of relations between overall performance and some manipulated variables, that is, the total plant performance. According to the big data of different performance statuses, this paper proposes a hierarchical framework to select some structured logic rules from monitored variables to estimate the current state of the process. The variables related to safety and profits are regarded as key factors to performance evaluation. To better monitor the process state and observe the performance variation trend of the process, a classificationvisualization method based on kernel principal component analysis(KPCA) and self-organizing map(SOM) is established. The dimensions of big data produced by the process are first reduced by KPCA and then the processed data will be mapped into a two-dimensional grid chart by SOM to evaluate the performance status. The monitoring method is applied to the Tennessee Eastman process. Monitoring results indicate that off-line and on-line performance status can be well detected in a two-dimensional diagram.展开更多
The paper attempts to make a preliminary exploration on the analytic framework of multi-generic phenomenon. Three strata have been identified in a multi-generic analytical framework and basic analytic unit for each st...The paper attempts to make a preliminary exploration on the analytic framework of multi-generic phenomenon. Three strata have been identified in a multi-generic analytical framework and basic analytic unit for each stratum has been well-established. Textual structure is identified as the basic analytic unit for texts, generic structural potential for member genres and schematic structure for multi-generic integration. Each basic analytic unit is responsible for generating the corresponding concrete form of representation.展开更多
Hierarchically porous metal-organic frameworks(H-MOFs)with micro-,meso-and macropores have emerged as a popular class of crystalline porous materials that have attracted extensive interests,and they have been studied ...Hierarchically porous metal-organic frameworks(H-MOFs)with micro-,meso-and macropores have emerged as a popular class of crystalline porous materials that have attracted extensive interests,and they have been studied in diverse applications,especially in heterogeneous catalysis.The hierarchical structures enable sufficient diffusion and accessibility to the active sites of the molecules and permit the encapsulation of catalytic vip molecules to exploit more possibilities with enhanced catalytic performance.In this review,we have summarized the recent representative developments of H-MOFs in the field of heterogeneous catalysis,which includes oxidation reaction,hydrogenation reaction,and condensation reaction.Emphasis is placed on the multiple functions of hierarchical structures,and the catalytic activity,selectivity,stability,recyclability,etc.of the industrial utility of H-MOFs.Finally,the prospects and challenges of H-MOFs in heterogeneous catalysis and the remaining issues in this field are presented.展开更多
Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode ...Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode cannot match the capacitor-type cathode, restricting the development of LICs. Herein, hierarchical carbon framework(HCF) anode material composed of 0D carbon nanocage bridged with 2D graphene network are developed via a template-confined synthesis process. The HCF with nanocage structure reduces the Li^(+) transport path and benefits the rapid Li^(+) migration, while 2D graphene network can promote the electron interconnecting of carbon nanocages. In addition, the doped N atoms in HCF facilitate to the adsorption of ions and enhance the pseudo contribution, thus accelerate the kinetics of the anode. The HCF anode delivers high specific capacity, remarkable rate capability. The LIC pouch-cell based on HCF anode and active HCF(a-HCF) cathode can provide a high energy density of 162 Wh kg^(-1) and a superior power density of 15.8 kW kg^(-1), as well as a long cycling life exceeding 15,000cycles. This study demonstrates that the well-defined design of hierarchical carbon framework by incorporating 0D carbon nanocages and 2D graphene network is an effective strategy to promote LIC anode kinetics and hence boost the LIC electrochemical performance.展开更多
Multiple enzymes-induced biological cascade catalysis is indispensable in biotechnology and industrial processes. Nevertheless,the drawbacks of most natural enzymes, including poor stability and recyclability and sens...Multiple enzymes-induced biological cascade catalysis is indispensable in biotechnology and industrial processes. Nevertheless,the drawbacks of most natural enzymes, including poor stability and recyclability and sensitivity to the environment, have hindered their broader application. Here, we report a facile strategy to prepare a biomimetic cascade reaction system by combining the advantages of enzyme immobilization and biomimetic catalysis in a one-pot reaction system based on the hierarchically porous metal-organic frameworks(HP-MOFs). The hierarchically porous zirconium-porphyrin-based MOF(HPPCN-222(Fe)) synthesized by modulator-induced strategy possessed tunable hierarchical porous and peroxidase-like activity,permitting them to act as not only an efficient immobilization matrix for glucose oxidase(GOx) but also peroxidase mimics to catalyze the cascade for glucose detection. A stable, anti-interference and reusable colorimetric biosensor for glucose detection was successfully established through GOx@HP-PCN-222(Fe) on the basis of the artificial tandem catalysis. Moreover, the GOx@HP-PCN-222(Fe)-fabricated electrode was available for glucose detection by electrochemical method. This work provides a potentially universal method to design functional multi-enzymatic cascade reaction systems by integrating the merits of enzyme encapsulation and biomimetic catalysis in HP-MOFs.展开更多
Commercial application of lithium-sulfur(Li-S) batteries is hindered by the insulating nature of sulfur and the dissolution of polysulfides. Here, a bioinspired 3D urchin-like N-doped Murray's carbon nanostructure...Commercial application of lithium-sulfur(Li-S) batteries is hindered by the insulating nature of sulfur and the dissolution of polysulfides. Here, a bioinspired 3D urchin-like N-doped Murray's carbon nanostructure(N-MCN) with interconnected micro-meso-macroporous structure and a polydopamine protection shell has been designed as an effective sulfur host for high-performance Li-S batteries. The advanced 3D hierarchically porous framework with the characteristics of the generalized Murray's law largely improves electrolyte diffusion, facilitates electrons/ions transfer and provides strong chemisorption for active species, leading to the synergistic structural and chemical confinement of polysulfides. As a result,the obtained P@S/N-MCN electrode with high areal sulfur loading demonstrates high capacity at high current densities after long cycles. This work reveals that following the generalized Murray's law is feasible to design high-performance sulfur cathode materials for potentially practical Li-S battery applications.展开更多
Facile synthesis conditions,abundant hierarchical porosity,and high space-time yields(STYs)are prerequisites for the commercial application of zeolitic imidazolate frameworks(ZIFs).However,these prerequisites are rare...Facile synthesis conditions,abundant hierarchical porosity,and high space-time yields(STYs)are prerequisites for the commercial application of zeolitic imidazolate frameworks(ZIFs).However,these prerequisites are rarely achieved simultaneously.Herein,a green and versatile strategy to rapidly synthesize hierarchically porous ZIFs(HP-ZIFs)was developed using an alkali as a deprotonating agent.The synthesis conditions were room temperature and ambient pressure in an aqueous solution,and the synthesis time could be reduced to 1 min.The produced HP-ZIFs had hierarchically porous structures with mesopores and macropores interconnected with micropores.The STY for HP-ZIFs was up to 9670 kg m^(-3)d^(-1),at least 712 times the previously reported values.In addition,the porosity and morphology of the produced HPZIFs could be fine-tuned by controlling the synthesis parameters(e.g.,reaction time,molar ratios,metal source,and alkali source).Compared with conventional ZIFs,the adsorption performance of the assynthesized HP-ZIFs for p-xylene and n-hexane was significantly improved.Positron annihilation lifetime spectroscopy(PALS)was utilized to study the pore properties,and the adsorption behavior of HP-ZIFs on vip molecules was investigated using density functional theory(DFT)simulations.This strategy shows significant promise for the large-scale industrial production of desirable HP-ZIFs for adsorption applications.展开更多
Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder ...Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder their practical applications.Herein,a metal oxyacid salts-confined pyrolysis strategy is proposed to construct hierarchical porous metal oxide@carbon(MO@C,MO=MoO_(2),V_(2)O_(5),WO_(3))composites for solving the aforementioned problems.A water-evaporation-induced self-assembly mechanism has been put forward for fabricating the MO@polyvinyl pyrrolidone(PVP)@SiO_(2)precursors.After the following pyrolysis and etching process,small MO nanoparticles can be successfully encapsulated in the hierarchical porous carbon framework.Profiting from the synergistic effect of MO nanoparticles and highly conductive carbon framework,MO@C composites show excellent electrochemical properties.For example,the as-obtained MoO_(2)@C composite exhibits a large discharge capacity(1513.7 mAh·g^(−1)at 0.1 A·g^(−1)),good rate ability(443.5 mAh·g^(−1)at 5.0 A·g^(−1)),supernal long-lived stability(669.1 mAh·g^(−1)after 1000 cycles at 1.0 A·g^(−1)).This work will inspire the design of novel anode materials for high-performance LIBs.展开更多
基金supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences under Grant No.2023112the National Natural Science Foundation of China under Grant No.62206266Zhao Zhang is supported by the China Postdoctoral Science Foundation under Grant No.2021M703273.
文摘Predicting the future trajectories of multiple agents is essential for various applications in real life,such as surveillance systems,autonomous driving,and social robots.The trajectory prediction task is influenced by many factors,including the individual historical trajectory,interactions between agents,and the fuzzy nature of the observed agents’motion.While existing methods have made great progress on the topic of trajectory prediction,they treat all the information uniformly,which limits the effectiveness of information utilization.To this end,in this paper,we propose and utilize a model-agnostic framework to regard all the information in a two-level hierarchical view.Particularly,the first-level view is the inter-trajectory view.In this level,we observe that the difficulty in predicting different trajectory samples varies.We define trajectory difficulty and train the proposed framework in an“easy-to-hard”schema.The second-level view is the intra-trajectory level.We find the influencing factors for a particular trajectory can be divided into two parts.The first part is global features,which keep stable within a trajectory,i.e.,the expected destination.The second part is local features,which change over time,i.e.,the current position.We believe that the two types of information should be handled in different ways.The hierarchical view is beneficial to take full advantage of the information in a fine-grained way.Experimental results validate the effectiveness of the proposed model-agnostic framework.
基金supported by the National Natural Science Foundation of China(22375081 and U21A20500)the Jiangxi Provincial Natural Science Foundation(20212ACB204016)the support from Nanchang University。
文摘A notable retiring wave for lithium iron phosphate(LiFePO_(4),LFP)-based lithium-ion batteries(LIBs)is expected in the coming years,which urges the establishment of complete and eco-friendly recycling chains.Currently,the industrial practice for these degraded LFP materials heavily relies on the hydrometallurgical strategies,which aim for the selective leaching of valuable Li element;this,however,leads to the accumulation of FePO_(4)by-product as a waste,which is neither economical nor sustainable.Considering the increasing demand on performance for next-generation LFP cathode materials,herein,we demonstrate a facile,green,and economic method to upcycle FePO_(4)residues from spent LIBs into high-performance LFP materials for direct reusages.The upcycling protocol involves simultaneous structural restoration of LFP lattices and hierarchical assembly of graphene-based conductive frameworks.As a result,the upcycled LFP cathode material delivers exceptional rate performance(discharge capacity of 125.6 mA h g^(-1)at 5 C or 93.6 mA h g^(-1)at 15 C)and cycling stability under high-rate conditions(capacity retention of 99.5%after 300 cycles at 1 C or 96.7%after 1000 cycles at 5 C).Moreover,the electrochemical performance is largely maintained at low temperatures.The upcycling strategy sheds light on the closed-loop development of LIB industry.
基金the financial supported by the National Natural Science Foundation of China(Nos.22109073,22072067 and 21875112)the Natural Science Foundation of Jiangsu Province(No.BK20200711)+2 种基金supported from the National and Local Joint Engineering Research Center of Biomedical Functional Materials and a project sponsored by the Priority Academic Program Development of Jiangsu Higher Education InstitutionsZ.Li thanks Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX21_1326)China Scholarship Council(No.202006860026).
文摘Developing high-efficiency and low-cost catalysts towards oxygen evolution reaction(OER)is extremely important for overall water splitting and rechargeable metal-air batteries.Herein we propose a promising organometallic coordination polymer(OCP)induced strategy to construct hierarchical N-doped carbon framework with NiFe nanoparticles encapsulated inside(NxFe@N-C)as a highly active and stable OER catalyst.The synthesis of OCP precursor depends on the unique molecular structure of iminodiacetonitrile(IDAN),which can coordinate with metal ions to form Ni2Fe(CN)6 with prussian blue analogs(PBA)structure.Unlike previous PBA-induced methods,the thickness of the carbon layer covering the surface of the metal core can be well controlled during the pyrolysis through adjusting the amount of IDAN,which builds a wonderful bridge for investigating the relationship between carbon layer thickness and catalytic performance.Both the experimental characterizations and theoretical studies validate that a suitable carbon layers thickness leads to optimal OER activity and stability.By optimizing the structure and composition,the optimized Ni_(3)Fe@N-C with hierarchical framework exhibits the low overpotentials(260 mV at 10 mA cm^(-2);320 mV at 50 mA cm^(-2)),improved kinetics(79 mV dec^(-1)),and robust long-term stability,which exceeds those of benchmark RuO_(2).
基金the National Key Research and Development Program(2019YFC1805804)the National Natural Science Foundation of China(22008032)+3 种基金the Guangdong Natural Science Foundation(2022A1515011192)the Guangdong Basic and Applied Basic Research Foundation(2019A1515110706)the Guangdong Provincial Key Lab of Green Chemical Product Technology(GC202111)the China Postdoctoral Science Foundation(2021M691059).
文摘The combination of nano sizes,large pore sizes and green synthesis is recognized as one of the most crucial and challenging problems in constructing metal-organic frameworks(MOFs).Herein,a water-based strategy is proposed for the synthesis of nanoscale hierarchical MOFs(NH-MOFs)with high crystallinity and excellent stability.This approach allows the morphology and porosity of MOFs to be fine tuned,thereby enabling the nanoscale crystal generation and a well-defined hierarchical system.The aqueous solution facilitates rapid nucleation kinetics,and the introduced modulator acts as a deprotonation agent to accelerate the deprotonation of the organic ligand as well as a structure-directing agent(SDA)to guide the formation of hierarchical networks.The assynthesized NH-MOFs(NH-ZIF-67)were assessed as efficient adsorbents and heterogeneous catalysts to facilitate the diffusion of vip molecules,outperforming the parent microZIF-67.This study focuses on understanding the NH-MOF growth rules,which could allow tailor-designing NH-MOFs for various functions.
基金supported by the National Key Research and Development Program Projects of China(No.2018YFC1504705)the National Natural Science Foundation of China(No.61731015)+1 种基金the Major instrument special project of National Natural Science Foundation of China(No.42027806)the Key Research and Development Program of Shaanxi(No.2022GY-331)。
文摘Wireless sensor networks(WSN)are widely used in many situations,but the disordered and random deployment mode will waste a lot of sensor resources.This paper proposes a multi-topology hierarchical collaborative particle swarm optimization(MHCHPSO)to optimize sensor deployment location and improve the coverage of WSN.MHCHPSO divides the population into three types topology:diversity topology for global exploration,fast convergence topology for local development,and collaboration topology for exploration and development.All topologies are optimized in parallel to overcome the precocious convergence of PSO.This paper compares with various heuristic algorithms at CEC 2013,CEC 2015,and CEC 2017.The experimental results show that MHCHPSO outperforms the comparison algorithms.In addition,MHCHPSO is applied to the WSN localization optimization,and the experimental results confirm the optimization ability of MHCHPSO in practical engineering problems.
基金supported by the National Natural Science Foundation of China(No.12071077).
文摘Recently,learned heuristics have been widely applied to solve combinatorial optimization problems(e.g.,traveling salesman problem(TSP)).However,the scalability of these learning-based methods hinders the applications in practical scenarios.Specifically,models pre-trained on the small-scale data generalize poorly to large-scale problems.Moreover,learning the heuristics directly for large-scale problems costs tremendous time and space.To extend the scalability of learned heuristics on TSP,we propose a Hierarchical neural framework for solving large-scale traveling salesman problems(HiTSPs)based on a divide-and-conquer strategy.In particular,the HiTSP framework first divides the large-scale problem into small-scale subproblems by node clustering.Each subproblem is conquered by a modified pointer network learned from reinforcement learning.The tour of the original TSP is constructed by linking solutions of subproblems and optimized by a novel segmented local search algorithm.Notably,the segmented local search algorithm leverages the node clustering information to prune many unnecessary operations and significantly reduces the complexity in theory.Extensive experiments show that HiTSP outperforms state-of-the-art learning-based methods and Google OR-Tools in large-scale cases.Moreover,compared to the best heuristic algorithms,HiTSP has a significant advantage in efficiency for large-scale TSP problems.
基金support of the“Pioneer”and“Leading Goose”Research&Development Program of Zhejiang(2024C01028)the State Key Laboratory of Industrial Control Technology,China(ICT2024C04)are gratefully acknowledged.
文摘Digital twin technology brings more opportunities and challenges to chemical engineering in both academic and industry.A complex process could have multiple digitalization needs,including simulation,monitoring,operator training,etc.;thus,a hierarchical digital twin would be a comprehensive solution to that.In this study,a novel and general framework of the digital twin is proposed for operations in process industry.With the hierarchical structure,the framework can handle various tasks driven by different roles in process industry,including managers,engineers,and operators.To complete these tasks,the framework consists of three modules:OAS(Operation Analysis System),OMS(Operation Monitoring System),and OTS(Operator Training System).Each module focuses on one unique type of demand from the staff,as well as interactions among them enabling efficient data sharing.Based on the hierarchical framework,a digital twin system is applied for one complex industrial nitration process,which successfully enhances the operation efficiency and safety in several industrial scenarios with different demands.
基金Supported by the National Natural Science Foundation of China(61590923,61422303,21376077)
文摘The performance evaluation of the process industry, which has been a popular topic nowadays, can not only find the weakness and verify the resilience and reliability of the process, but also provide some suggestions to improve the process benefits and efficiency. Nevertheless, the performance assessment principally concentrates upon some parts of the entire system at present, for example the controller assessment. Although some researches focus on the whole process, they aim at discovering the relationships between profit, society, policies and so forth, instead of relations between overall performance and some manipulated variables, that is, the total plant performance. According to the big data of different performance statuses, this paper proposes a hierarchical framework to select some structured logic rules from monitored variables to estimate the current state of the process. The variables related to safety and profits are regarded as key factors to performance evaluation. To better monitor the process state and observe the performance variation trend of the process, a classificationvisualization method based on kernel principal component analysis(KPCA) and self-organizing map(SOM) is established. The dimensions of big data produced by the process are first reduced by KPCA and then the processed data will be mapped into a two-dimensional grid chart by SOM to evaluate the performance status. The monitoring method is applied to the Tennessee Eastman process. Monitoring results indicate that off-line and on-line performance status can be well detected in a two-dimensional diagram.
文摘The paper attempts to make a preliminary exploration on the analytic framework of multi-generic phenomenon. Three strata have been identified in a multi-generic analytical framework and basic analytic unit for each stratum has been well-established. Textual structure is identified as the basic analytic unit for texts, generic structural potential for member genres and schematic structure for multi-generic integration. Each basic analytic unit is responsible for generating the corresponding concrete form of representation.
基金supported by the National Natural Science Foundation of China(22008032,12105048,and 22078104)Guangdong Basic and Applied Basic Research Foundation(2019A1515110706 and 2020A1515110817)+5 种基金the Science and Technology Key Project of Guangdong Province,China(2020B010188002)the Special Innovation Projects of Universities in Guangdong Province(2018KTSCX240)the Innovation Team of Universities in Guangdong Province(2020KCXTD011)the Engineering Research Center of Universities in Guangdong Province(2019GCZX002)Guangdong Key Laboratory for Hydrogen Energy Technologies(2018B030322005)Guangdong Provincial Key Lab of Green Chemical Product Technology(GC202111)。
文摘Hierarchically porous metal-organic frameworks(H-MOFs)with micro-,meso-and macropores have emerged as a popular class of crystalline porous materials that have attracted extensive interests,and they have been studied in diverse applications,especially in heterogeneous catalysis.The hierarchical structures enable sufficient diffusion and accessibility to the active sites of the molecules and permit the encapsulation of catalytic vip molecules to exploit more possibilities with enhanced catalytic performance.In this review,we have summarized the recent representative developments of H-MOFs in the field of heterogeneous catalysis,which includes oxidation reaction,hydrogenation reaction,and condensation reaction.Emphasis is placed on the multiple functions of hierarchical structures,and the catalytic activity,selectivity,stability,recyclability,etc.of the industrial utility of H-MOFs.Finally,the prospects and challenges of H-MOFs in heterogeneous catalysis and the remaining issues in this field are presented.
基金the financial support by the National Science Foundation of China(51822706 and 52107234)Beijing Natural Science Foundation(JQ19012)+2 种基金the DNL Cooperation Fund,CAS(DNL201912 and DNL201915)Innovation Academy for Green Manufacture Fund(IAGM2020C02)Youth Innovation Promotion Association,CAS(Y2021052).
文摘Lithium-ion capacitors(LICs) combining the advantages of lithium-ion batteries and supercapacitors are considered a promising nextgeneration energy storage device. However, the sluggish kinetics of battery-type anode cannot match the capacitor-type cathode, restricting the development of LICs. Herein, hierarchical carbon framework(HCF) anode material composed of 0D carbon nanocage bridged with 2D graphene network are developed via a template-confined synthesis process. The HCF with nanocage structure reduces the Li^(+) transport path and benefits the rapid Li^(+) migration, while 2D graphene network can promote the electron interconnecting of carbon nanocages. In addition, the doped N atoms in HCF facilitate to the adsorption of ions and enhance the pseudo contribution, thus accelerate the kinetics of the anode. The HCF anode delivers high specific capacity, remarkable rate capability. The LIC pouch-cell based on HCF anode and active HCF(a-HCF) cathode can provide a high energy density of 162 Wh kg^(-1) and a superior power density of 15.8 kW kg^(-1), as well as a long cycling life exceeding 15,000cycles. This study demonstrates that the well-defined design of hierarchical carbon framework by incorporating 0D carbon nanocages and 2D graphene network is an effective strategy to promote LIC anode kinetics and hence boost the LIC electrochemical performance.
基金supported by the National Natural Science Foundation of China (92061201, 21825106, 22001238)the Program for Innovative Research Team (in Science and Technology) in Universities of Henan Province (19IRTSTHN022)Zhengzhou University。
文摘Multiple enzymes-induced biological cascade catalysis is indispensable in biotechnology and industrial processes. Nevertheless,the drawbacks of most natural enzymes, including poor stability and recyclability and sensitivity to the environment, have hindered their broader application. Here, we report a facile strategy to prepare a biomimetic cascade reaction system by combining the advantages of enzyme immobilization and biomimetic catalysis in a one-pot reaction system based on the hierarchically porous metal-organic frameworks(HP-MOFs). The hierarchically porous zirconium-porphyrin-based MOF(HPPCN-222(Fe)) synthesized by modulator-induced strategy possessed tunable hierarchical porous and peroxidase-like activity,permitting them to act as not only an efficient immobilization matrix for glucose oxidase(GOx) but also peroxidase mimics to catalyze the cascade for glucose detection. A stable, anti-interference and reusable colorimetric biosensor for glucose detection was successfully established through GOx@HP-PCN-222(Fe) on the basis of the artificial tandem catalysis. Moreover, the GOx@HP-PCN-222(Fe)-fabricated electrode was available for glucose detection by electrochemical method. This work provides a potentially universal method to design functional multi-enzymatic cascade reaction systems by integrating the merits of enzyme encapsulation and biomimetic catalysis in HP-MOFs.
基金financially supported by National Key Research and Development Program of China [2016YFA0202602, 2021YFE0115800]National Natural Science Foundation of China [22275142, U22B6011, U20A20122, 21671155]+4 种基金Program of Introducing Talents of Discipline to Universities-Plan 111 from the Ministry of Science and Technology and the Ministry of Education of China [Grant No. B20002]Sinopec Ministry of Science and Technology Basic Prospective Research Project [218025-9]Natural Science Foundation of Hubei Province [2021CFB082]Scientific Research Foundation of Wuhan Institute of Technology [K2021042]the Open Key Fund Project of State Key Laboratory of Advanced Technology for Materials Synthesis and Processing [Wuhan University of Technology, 2022-KF-10]。
文摘Commercial application of lithium-sulfur(Li-S) batteries is hindered by the insulating nature of sulfur and the dissolution of polysulfides. Here, a bioinspired 3D urchin-like N-doped Murray's carbon nanostructure(N-MCN) with interconnected micro-meso-macroporous structure and a polydopamine protection shell has been designed as an effective sulfur host for high-performance Li-S batteries. The advanced 3D hierarchically porous framework with the characteristics of the generalized Murray's law largely improves electrolyte diffusion, facilitates electrons/ions transfer and provides strong chemisorption for active species, leading to the synergistic structural and chemical confinement of polysulfides. As a result,the obtained P@S/N-MCN electrode with high areal sulfur loading demonstrates high capacity at high current densities after long cycles. This work reveals that following the generalized Murray's law is feasible to design high-performance sulfur cathode materials for potentially practical Li-S battery applications.
基金support from the National Natural Science Foundation of China(22008032)the Guangdong Basic and Applied Basic Research Foundation(2023A1515011881,2024A1515030172,2022A1515011192,and 2023A1515010679)+3 种基金the Guangxi Key Laboratory of Green Chemical Materials and Safety Technology,College of Petroleum and Chemical Engineering,Beibu Gulf University(2023SYSZZ07)the Key Project of Biomedicine and Health in Colleges and Universities of Guangdong Province(2021ZDZX2055)the Medical Science and Technology Research Fund of Guangdong Province(A2022004)the National Undergraduate Training Program for Innovation and Entrepreneurship(202311847002).
文摘Facile synthesis conditions,abundant hierarchical porosity,and high space-time yields(STYs)are prerequisites for the commercial application of zeolitic imidazolate frameworks(ZIFs).However,these prerequisites are rarely achieved simultaneously.Herein,a green and versatile strategy to rapidly synthesize hierarchically porous ZIFs(HP-ZIFs)was developed using an alkali as a deprotonating agent.The synthesis conditions were room temperature and ambient pressure in an aqueous solution,and the synthesis time could be reduced to 1 min.The produced HP-ZIFs had hierarchically porous structures with mesopores and macropores interconnected with micropores.The STY for HP-ZIFs was up to 9670 kg m^(-3)d^(-1),at least 712 times the previously reported values.In addition,the porosity and morphology of the produced HPZIFs could be fine-tuned by controlling the synthesis parameters(e.g.,reaction time,molar ratios,metal source,and alkali source).Compared with conventional ZIFs,the adsorption performance of the assynthesized HP-ZIFs for p-xylene and n-hexane was significantly improved.Positron annihilation lifetime spectroscopy(PALS)was utilized to study the pore properties,and the adsorption behavior of HP-ZIFs on vip molecules was investigated using density functional theory(DFT)simulations.This strategy shows significant promise for the large-scale industrial production of desirable HP-ZIFs for adsorption applications.
基金the Taishan Scholar Project of Shandong Province(No.tsqn201909115)And this work was partly supported by Qingdao University of Science and Technology Hua Xue 201919(No.QUSTHX201919).
文摘Transition metal oxides(TMOs)have been thought of potential anodic materials for lithium-ion batteries(LIBs)owing to their intriguing properties.However,the limited conductivity and drastic volume change still hinder their practical applications.Herein,a metal oxyacid salts-confined pyrolysis strategy is proposed to construct hierarchical porous metal oxide@carbon(MO@C,MO=MoO_(2),V_(2)O_(5),WO_(3))composites for solving the aforementioned problems.A water-evaporation-induced self-assembly mechanism has been put forward for fabricating the MO@polyvinyl pyrrolidone(PVP)@SiO_(2)precursors.After the following pyrolysis and etching process,small MO nanoparticles can be successfully encapsulated in the hierarchical porous carbon framework.Profiting from the synergistic effect of MO nanoparticles and highly conductive carbon framework,MO@C composites show excellent electrochemical properties.For example,the as-obtained MoO_(2)@C composite exhibits a large discharge capacity(1513.7 mAh·g^(−1)at 0.1 A·g^(−1)),good rate ability(443.5 mAh·g^(−1)at 5.0 A·g^(−1)),supernal long-lived stability(669.1 mAh·g^(−1)after 1000 cycles at 1.0 A·g^(−1)).This work will inspire the design of novel anode materials for high-performance LIBs.
