Pavement construction in permafrost regions is complicated by the fact that the permafrost properties are influenced by the temperature and are extremely unstable.The numerical model for runway structures in permafros...Pavement construction in permafrost regions is complicated by the fact that the permafrost properties are influenced by the temperature and are extremely unstable.The numerical model for runway structures in permafrost regions is applied to analyze the time–space characteristics of the temperature field and the depth of the frozen layer.The influence of the installation layer is studied to enable structural optimization of the runway.Numerical results show that the temperature stabilization depth,low-and high-temperature interlayer response ranges,and maximum depth of the frozen layer are greater in runway engineering than in highway and railway engineering.The time history curves for the pavement and natural surface are similar,and the development of freezing and thawing is approximately linear.The pavement and natural surface have similar thawing rates,but the freezing rate of the natural surface is faster than that of the pavement.The depth of the frozen layer and the time of the frozen are greater for the natural surface than for the pavement.The installation layer helps to stabilize the temperature of the subgrade and reduces the freezing and thawing rates.This study provides technical support for the design and maintenance of runways in permafrost regions.展开更多
In this paper, we focus on investigation of the predicate transformer semantics of the contract language introduced by Back and von Wright in their book titled as “Refinement Calculus: A Systematic Introduction” (Sp...In this paper, we focus on investigation of the predicate transformer semantics of the contract language introduced by Back and von Wright in their book titled as “Refinement Calculus: A Systematic Introduction” (Springer-Verlag, New York, 1998) in the framework of fuzziness. In order to define fuzzy operations, i.e., fuzzy logic connectives, we take into account implicator → and its associated based on residuated lattice theory. Based on these basic fuzzy operations, we introduce the angelic and demonic updates of fuzzy relations. They are the basis of fuzzy predicate transformers in the sense of that any strongly monotone fuzzy predicate transformer can be represented as the sequential composition of the angelic and demonic updates. Together with the standard strong negation , we set up the duality between the angel and demon. The fuzzy predicate transformers semantics of contract statements is established and a simple example of contract statements is given.展开更多
The elbow erosion seriously jeopardizes the safe and stable operation of water–slag discharge pipeline of the coal gasification system.This work simulated water–slag elbow characteristics with various slag injection...The elbow erosion seriously jeopardizes the safe and stable operation of water–slag discharge pipeline of the coal gasification system.This work simulated water–slag elbow characteristics with various slag injection positions by simulating five simplified and representative erosion categories,including A-type horizontal-vertical elbow with an upstream flow,B-type horizontal-vertical elbow with a downstream flow,C-type vertical-horizontal elbow with an upstream flow,D-type vertical-horizontal elbow with a downstream flow and E-type horizontal-horizontal elbow.Compared with the C/D-type elbow,where particles were injected uniformly,the A-type elbow and E-type elbow were found to increase erosion rate,while the B-type elbow decreases erosion rate.An interesting discovery is that the elbow erosion rate is relatively low for small particles when particles are injected from the middle and bottom positions of the inlet section of the elbow.Based on the observation,a novel preceding rotating sheet structure was developed to regulate the particle injection position.It shows an excellent anti-erosion performance by reducing the maximum erosion rate of particles with diameters of 50,100,and 200μm by 23%,35%,and 43%,respectively.展开更多
1.Fluid metasomatism in subduction zones Subduction zones are the key tectonic setting that links Earth's surficial sphere to deep sphere(Zheng and Chen,2016).Fluid action occurring in subduction zones is closely ...1.Fluid metasomatism in subduction zones Subduction zones are the key tectonic setting that links Earth's surficial sphere to deep sphere(Zheng and Chen,2016).Fluid action occurring in subduction zones is closely related to many important geological processes such as volcanic and seismic activity,the migration,enrichment and mineralization of metallogenic elements,mass transport and crust-mantle material cycling,and the evolution of Earth's surface environment.Therefore,it is of great significance to study the sources,properties and geochemical effects of subduction zone fluids(Zheng,2019).展开更多
Oceanic lithosphere is generated at divergent plate boundaries and disappears at convergent plate boundaries.Seafloor spreading and plate subduction together constitute the physical coupling and mass conservation rela...Oceanic lithosphere is generated at divergent plate boundaries and disappears at convergent plate boundaries.Seafloor spreading and plate subduction together constitute the physical coupling and mass conservation relationships to the movement of lithospheres on Earth.Subduction zones are a key site for the transfer of both matter and energy at converging plate boundaries,and their study has been the hot spot and frontier of Earth system science since the development of plate tectonics theory.As far as the dynamic regime and geothermal gradient of convergent plate margins are concerned,they have different properties in different stages of the subduction zone evolution.In general,the early low-angle subduction leads to compressional tectonism dominated by low geothermal gradients at the plate interface,and the late high-angle subduction results in extensional tectonism dominated by high geothermal gradients at the plate interface and its hanging wall.Active rifts are produced along suture zones through not only slab rollback or slab breakoff in the terminal stage of oceanic subduction but also foundering and thinning of the lithosphere in the post-subduction stage.Due to the differences and changes in the geometric and thermobaric structures of convergent plate margins,a series of changes in the type of metamorphism and magmatism can occur in active and fossil subduction zones.Dehydration and melting of the subducting oceanic crust are prominent at subarc depths,giving rise to fluids that dissolve different concentrations of fluid-mobile incompatible elements.The subduction zone fluids at subarc depths would chemically react with the overlying mantle wedge peridotite,generating metasomatites as the mantle sources of mafic magmas in oceanic and continental arcs.However,these metasomatites did not partially melt immediately upon the fluid metasomatism to trigger arc magmatism,and they did not melt until they were heated by asthenospheric convection due to rollback of the subducting slab.Therefore,recognition of the changes in the dynamic regime and geothermal gradient of subduction zones in different stages of plate convergence not only provides insights into geodynamic mechanisms of the tectonic evolution from subduction zones to orogenic belts,but also places constraints on the formation and evolution of different types of metamorphic and magmatic rocks within the advanced framework of plate tectonics.展开更多
Oxygen fugacity(fO_(2))is an intensive variable that describes the redox state of a system.By controlling the valence state of multivalent elements,fO_(2)affects the stability of iron-bearing minerals,dominants the sp...Oxygen fugacity(fO_(2))is an intensive variable that describes the redox state of a system.By controlling the valence state of multivalent elements,fO_(2)affects the stability of iron-bearing minerals,dominants the species of volatile elements(e.g.,carbon and sulfur),and controls the partitioning behaviors of multivalent elements(e.g.,iron,vanadium,cerium,europium).Thus,fO_(2)plays a key role in understanding the generation and differentiation of arc magmas,the formation of magmatic-hydrothermal deposits,and the nature of magmatic volatiles.Subduction zones are an important site for arc magmatism and fluid action,and the study of redox processes is indispensable in subduction zone geochemistry.In this paper,we first introduce the concept,expression,and estimation methods of fO_(2).Then we retrospect the history and progress about the oxidation state of the metasomatized mantle wedge,summarize the redox property of slab-derived fluids,and review the latest progress on redox evolution of arc magmas during magma generation and differentiation.The main conclusions include:(1)despite its wide variation range,fO_(2)of the mantle wedge is generally higher than that of the oceanic mantle;(2)the redox property of the subducting slab-derived fluids is still controversial and the mechanism for the oxidization of the mantle wedge remains unclear;(3)how the fO_(2)varies during the generation and differentiation of the arc magmas is debated.We propose that the crux in deciphering the oxidization mechanism of the mantle wedge is to determine the mobility of iron,carbon and sulfur in subducting slab-derived fluids(especially solute-rich fluid or supercritical fluid);the key in understanding the redox evolution during arc magma generation and differentiation is to determine the partition coefficients of Fe^(3+)and Fe^(2+)between ferromagnesian minerals and silicate melts.展开更多
The Spatio-Temporal Consistency Language(STeC)is a high-level modeling language that deals natively with spatio-temporal behaviour,i.e.,behaviour relating to certain locations and time.Such restriction by both locatio...The Spatio-Temporal Consistency Language(STeC)is a high-level modeling language that deals natively with spatio-temporal behaviour,i.e.,behaviour relating to certain locations and time.Such restriction by both locations and time is of first importance for some types of real-time systems.CCSL is a formal specification language based on logical clocks.It is used to describe some crucial safety properties for real-time systems,due to its powerful expressiveness of logical and chronometric time constraints.We consider a novel verification framework combining STeC and CCSL,with the advantages of addressing spatio-temporal consistency of system behaviour and easily expressing some crucial time constraints.We propose a theory combining these two languages and a method verifying CCSL properties in STeC models.We adopt UPPAAL as the model checking tool and give a simple example to illustrate how to carry out verification in our framework.展开更多
Two-thirds simulation provides a kind of abstract description of an implementation with respect to a specification. In order to characterize the approximate two-thirds simulation, we propose the definition of a two- t...Two-thirds simulation provides a kind of abstract description of an implementation with respect to a specification. In order to characterize the approximate two-thirds simulation, we propose the definition of a two- thirds simulation index which expresses the degree to which a binary relation between processes is two-thirds simulation. 2-two-thirds simulation and its substitutivity laws are given in this paper. And, based on 2-two-thirds simulation, we present a measure model for describing the degree of approximation between processes. In particular, we give the modal logical characterization of 2-two-thirds simulation.展开更多
This paper presents an approach to build a communication behavioural semantic model for heterogeneous distributed systems that include synchronous and asynchronous communications. Since each node of such system has it...This paper presents an approach to build a communication behavioural semantic model for heterogeneous distributed systems that include synchronous and asynchronous communications. Since each node of such system has its own physical clock, it brings the challenges of correctly specifying the system time constraints. Based on the logical clocks proposed by Lamport, and CCSL proposed by Aoste team in INRIA, as well as pNets from Oasis team in INRIA, we develop timed-pNets to model communication behaviours for distributed systems. Timed-pNets are tree style hierarchical structures. Each node is associated with a timed specification which consists of a set of logical clocks and some relations on clocks. The leaves are represented by timed-pLTSs. Non-leaf nodes （called timed-pNets nodes） are synchronisation devices that synchronize the behaviours of subnets （these subnets can be leaves or non-leaf nodes）. Both timed-pLTSs and timed-pNets nodes can be translated to timed specifications. All these notions and methods are illustrated on a simple use-case of car insertion from the area of intelligent transportation systems （ITS）. In the end the TimeSquare tool is used to simulate and check the validity of our model.展开更多
The Internet-of-Things(IoT)is expected to swamp the world.In order to study and understand the emergent behaviour of connected things,effective support for their modelling is needed.At the heart of IoT are flexible an...The Internet-of-Things(IoT)is expected to swamp the world.In order to study and understand the emergent behaviour of connected things,effective support for their modelling is needed.At the heart of IoT are flexible and adaptive connection patterns between things,which can naturally be modelled by channel-based coordination primitives,and characteristics of connection failure probabilities,execution and waiting times,as well as resource consumption.The latter is especially important in light of severely limited power and computation budgets inside the things.In this paper,we tackle the IoT modelling challenge,based on a conservative extension of channel-based Reo circuits.We introduce a model called priced probabilistic timed constraint automaton,which combines models of probabilistic and timed aspects,and integrates pricing information.An expressive logic called priced probabilistic timed scheduled data stream logic is presented,so as to enable the specification and verification of properties,which characterize data-flow streams and prices.A small but illustrative IoT case demonstrates the principal benefits of the proposed approach.展开更多
Mixed-valence metallic compounds are a class of functional materials with peculiar electrochemical properties.Exploring the correlation between defects and corrosion resistance of mixed-valence metallic compounds is a...Mixed-valence metallic compounds are a class of functional materials with peculiar electrochemical properties.Exploring the correlation between defects and corrosion resistance of mixed-valence metallic compounds is a novel and interesting subject.Through an intelligently designed synergistic process of reduction and directed assembly,not only the directional generation of oxygen vacancies along the normal direction of the(010)crystal plane was achieved,but also the W_(18)O_(49)mixed-valence metal oxide(MVMO)with a single crystalline phase and an assembled ordered three-dimensional cluster structure of nanorods was obtained.Three attractive effects of oriented oxygen vacancies in W_(18)O_(49)MVMO were discovered.First,the oxygen vacancy channels realized the directional concentrated transport of oxygen atoms to form dense oxide passivation film.Second,the directional concentrated oxygen vacancies as active centers effectively solved the problem of difficult photoelectron leap and separation of pure-phase semiconductors,realizing photogenerated cathodic protection.Third,the high-energy vacancies endowed the material with antibacterial function,which contributed to the stable existence of the anti-corrosion system.The resistance value of W_(18)O_(49)MVMO as an anti-corrosion functional material was increased to more than 4.00 times that of the original metal protection layer.The experimental results obtained in this research were of great reference value for revealing the intrinsic mechanism of correlation between oxygen defect orientation of MVMOs and electrochemistry.展开更多
基金the National Natural Science Foundation of China(Grant No.52108333)the Natural Science Foundation of Tianjin(Grant Nos.18JCQNJC08300,18JCYBJC90800,20JCQNJC01320)the Key Laboratory of Road Structure and Materials Transportation Industry(Grant No.310821171114)for providing the funding that made this study possible.
文摘Pavement construction in permafrost regions is complicated by the fact that the permafrost properties are influenced by the temperature and are extremely unstable.The numerical model for runway structures in permafrost regions is applied to analyze the time–space characteristics of the temperature field and the depth of the frozen layer.The influence of the installation layer is studied to enable structural optimization of the runway.Numerical results show that the temperature stabilization depth,low-and high-temperature interlayer response ranges,and maximum depth of the frozen layer are greater in runway engineering than in highway and railway engineering.The time history curves for the pavement and natural surface are similar,and the development of freezing and thawing is approximately linear.The pavement and natural surface have similar thawing rates,but the freezing rate of the natural surface is faster than that of the pavement.The depth of the frozen layer and the time of the frozen are greater for the natural surface than for the pavement.The installation layer helps to stabilize the temperature of the subgrade and reduces the freezing and thawing rates.This study provides technical support for the design and maintenance of runways in permafrost regions.
文摘In this paper, we focus on investigation of the predicate transformer semantics of the contract language introduced by Back and von Wright in their book titled as “Refinement Calculus: A Systematic Introduction” (Springer-Verlag, New York, 1998) in the framework of fuzziness. In order to define fuzzy operations, i.e., fuzzy logic connectives, we take into account implicator → and its associated based on residuated lattice theory. Based on these basic fuzzy operations, we introduce the angelic and demonic updates of fuzzy relations. They are the basis of fuzzy predicate transformers in the sense of that any strongly monotone fuzzy predicate transformer can be represented as the sequential composition of the angelic and demonic updates. Together with the standard strong negation , we set up the duality between the angel and demon. The fuzzy predicate transformers semantics of contract statements is established and a simple example of contract statements is given.
基金the National Natural Science Foundation of China(grant No.22278332)Shaanxi Province's Key Research and Development Plan(grant No.2023-YBGY-317,2023-YBGY-175)+1 种基金Natural Science Basic Research Program of Shaanxi(grant No.2020JQ-597)Natural Science Foundation of Shaanxi Provincial Department of Education(grant No.23JK0723).
文摘The elbow erosion seriously jeopardizes the safe and stable operation of water–slag discharge pipeline of the coal gasification system.This work simulated water–slag elbow characteristics with various slag injection positions by simulating five simplified and representative erosion categories,including A-type horizontal-vertical elbow with an upstream flow,B-type horizontal-vertical elbow with a downstream flow,C-type vertical-horizontal elbow with an upstream flow,D-type vertical-horizontal elbow with a downstream flow and E-type horizontal-horizontal elbow.Compared with the C/D-type elbow,where particles were injected uniformly,the A-type elbow and E-type elbow were found to increase erosion rate,while the B-type elbow decreases erosion rate.An interesting discovery is that the elbow erosion rate is relatively low for small particles when particles are injected from the middle and bottom positions of the inlet section of the elbow.Based on the observation,a novel preceding rotating sheet structure was developed to regulate the particle injection position.It shows an excellent anti-erosion performance by reducing the maximum erosion rate of particles with diameters of 50,100,and 200μm by 23%,35%,and 43%,respectively.
基金funded by the National Natural Science Foundation of China(Grant Nos.42073029,42273043)the Fundamental Research Funds for the Central Universities。
文摘1.Fluid metasomatism in subduction zones Subduction zones are the key tectonic setting that links Earth's surficial sphere to deep sphere(Zheng and Chen,2016).Fluid action occurring in subduction zones is closely related to many important geological processes such as volcanic and seismic activity,the migration,enrichment and mineralization of metallogenic elements,mass transport and crust-mantle material cycling,and the evolution of Earth's surface environment.Therefore,it is of great significance to study the sources,properties and geochemical effects of subduction zone fluids(Zheng,2019).
基金the project on the development strategy of subduction zones that was supported not only by a fund from the Chinese Academy of Sciences(2015-2016)by a joint fund from the National Natural Science Foundation of China and the Chinese Academy of Sciences(2018-2019)supported by the National Natural Science Foundation of China(Grant No.92155306)。
文摘Oceanic lithosphere is generated at divergent plate boundaries and disappears at convergent plate boundaries.Seafloor spreading and plate subduction together constitute the physical coupling and mass conservation relationships to the movement of lithospheres on Earth.Subduction zones are a key site for the transfer of both matter and energy at converging plate boundaries,and their study has been the hot spot and frontier of Earth system science since the development of plate tectonics theory.As far as the dynamic regime and geothermal gradient of convergent plate margins are concerned,they have different properties in different stages of the subduction zone evolution.In general,the early low-angle subduction leads to compressional tectonism dominated by low geothermal gradients at the plate interface,and the late high-angle subduction results in extensional tectonism dominated by high geothermal gradients at the plate interface and its hanging wall.Active rifts are produced along suture zones through not only slab rollback or slab breakoff in the terminal stage of oceanic subduction but also foundering and thinning of the lithosphere in the post-subduction stage.Due to the differences and changes in the geometric and thermobaric structures of convergent plate margins,a series of changes in the type of metamorphism and magmatism can occur in active and fossil subduction zones.Dehydration and melting of the subducting oceanic crust are prominent at subarc depths,giving rise to fluids that dissolve different concentrations of fluid-mobile incompatible elements.The subduction zone fluids at subarc depths would chemically react with the overlying mantle wedge peridotite,generating metasomatites as the mantle sources of mafic magmas in oceanic and continental arcs.However,these metasomatites did not partially melt immediately upon the fluid metasomatism to trigger arc magmatism,and they did not melt until they were heated by asthenospheric convection due to rollback of the subducting slab.Therefore,recognition of the changes in the dynamic regime and geothermal gradient of subduction zones in different stages of plate convergence not only provides insights into geodynamic mechanisms of the tectonic evolution from subduction zones to orogenic belts,but also places constraints on the formation and evolution of different types of metamorphic and magmatic rocks within the advanced framework of plate tectonics.
基金the National Key Research and Development Program of China(Grant No.2018YFA0702704)the National Natural Science Foundation of China(Grant No.41921003)the Key Research Project of Frontier Science of the Chinese Academy of Sciences(Grant No.QYZDJ-SSW-DQC012).
文摘Oxygen fugacity(fO_(2))is an intensive variable that describes the redox state of a system.By controlling the valence state of multivalent elements,fO_(2)affects the stability of iron-bearing minerals,dominants the species of volatile elements(e.g.,carbon and sulfur),and controls the partitioning behaviors of multivalent elements(e.g.,iron,vanadium,cerium,europium).Thus,fO_(2)plays a key role in understanding the generation and differentiation of arc magmas,the formation of magmatic-hydrothermal deposits,and the nature of magmatic volatiles.Subduction zones are an important site for arc magmatism and fluid action,and the study of redox processes is indispensable in subduction zone geochemistry.In this paper,we first introduce the concept,expression,and estimation methods of fO_(2).Then we retrospect the history and progress about the oxidation state of the metasomatized mantle wedge,summarize the redox property of slab-derived fluids,and review the latest progress on redox evolution of arc magmas during magma generation and differentiation.The main conclusions include:(1)despite its wide variation range,fO_(2)of the mantle wedge is generally higher than that of the oceanic mantle;(2)the redox property of the subducting slab-derived fluids is still controversial and the mechanism for the oxidization of the mantle wedge remains unclear;(3)how the fO_(2)varies during the generation and differentiation of the arc magmas is debated.We propose that the crux in deciphering the oxidization mechanism of the mantle wedge is to determine the mobility of iron,carbon and sulfur in subducting slab-derived fluids(especially solute-rich fluid or supercritical fluid);the key in understanding the redox evolution during arc magma generation and differentiation is to determine the partition coefficients of Fe^(3+)and Fe^(2+)between ferromagnesian minerals and silicate melts.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61370100,61321064)Shanghai Knowledge Service Platform Project(ZF1213)+1 种基金Shanghai Municipal Science and Technology Commission Project(14511100400)Defense Industrial Technology Development Program JCKY(2016212B004-2).
文摘The Spatio-Temporal Consistency Language(STeC)is a high-level modeling language that deals natively with spatio-temporal behaviour,i.e.,behaviour relating to certain locations and time.Such restriction by both locations and time is of first importance for some types of real-time systems.CCSL is a formal specification language based on logical clocks.It is used to describe some crucial safety properties for real-time systems,due to its powerful expressiveness of logical and chronometric time constraints.We consider a novel verification framework combining STeC and CCSL,with the advantages of addressing spatio-temporal consistency of system behaviour and easily expressing some crucial time constraints.We propose a theory combining these two languages and a method verifying CCSL properties in STeC models.We adopt UPPAAL as the model checking tool and give a simple example to illustrate how to carry out verification in our framework.
文摘Two-thirds simulation provides a kind of abstract description of an implementation with respect to a specification. In order to characterize the approximate two-thirds simulation, we propose the definition of a two- thirds simulation index which expresses the degree to which a binary relation between processes is two-thirds simulation. 2-two-thirds simulation and its substitutivity laws are given in this paper. And, based on 2-two-thirds simulation, we present a measure model for describing the degree of approximation between processes. In particular, we give the modal logical characterization of 2-two-thirds simulation.
基金This work was partially funded by the INRIA Associated Team DAESD between INRIA and ECNU by the National Basic Research Program of China （973 Program） （2011CB302802）+1 种基金 by the National Natural Science Foundation of China （Grant Nos. 61321064 and 61370100） by Shanghai Knowledge Service Platform Project （ZF1213）. We give great thanks to Frederic Mallet and Jalien Deantoni who took time to discuss with us and gave us bunches of advices. We are also indebted to the anonymous referees for their suggested improvements.
文摘This paper presents an approach to build a communication behavioural semantic model for heterogeneous distributed systems that include synchronous and asynchronous communications. Since each node of such system has its own physical clock, it brings the challenges of correctly specifying the system time constraints. Based on the logical clocks proposed by Lamport, and CCSL proposed by Aoste team in INRIA, as well as pNets from Oasis team in INRIA, we develop timed-pNets to model communication behaviours for distributed systems. Timed-pNets are tree style hierarchical structures. Each node is associated with a timed specification which consists of a set of logical clocks and some relations on clocks. The leaves are represented by timed-pLTSs. Non-leaf nodes （called timed-pNets nodes） are synchronisation devices that synchronize the behaviours of subnets （these subnets can be leaves or non-leaf nodes）. Both timed-pLTSs and timed-pNets nodes can be translated to timed specifications. All these notions and methods are illustrated on a simple use-case of car insertion from the area of intelligent transportation systems （ITS）. In the end the TimeSquare tool is used to simulate and check the validity of our model.
基金supported by the National Natural Science Foundation of China(Grant Nos.61370100,61321064 and 61773019)Shanghai Knowledge Service Platform for Trustworthy Internet of Things(ZF1213)+2 种基金Shanghai Municipal Science and Technology Commission Project(1451100400)Defense Industrial Technology Development Program JCKY 2016212B004-2,by the ERC Advanced Grant 695614(POWVER)by the Sino-German Center for Research Project CAP(GZ 1023).
文摘The Internet-of-Things(IoT)is expected to swamp the world.In order to study and understand the emergent behaviour of connected things,effective support for their modelling is needed.At the heart of IoT are flexible and adaptive connection patterns between things,which can naturally be modelled by channel-based coordination primitives,and characteristics of connection failure probabilities,execution and waiting times,as well as resource consumption.The latter is especially important in light of severely limited power and computation budgets inside the things.In this paper,we tackle the IoT modelling challenge,based on a conservative extension of channel-based Reo circuits.We introduce a model called priced probabilistic timed constraint automaton,which combines models of probabilistic and timed aspects,and integrates pricing information.An expressive logic called priced probabilistic timed scheduled data stream logic is presented,so as to enable the specification and verification of properties,which characterize data-flow streams and prices.A small but illustrative IoT case demonstrates the principal benefits of the proposed approach.
基金This work was supported by the National Natural Science Foundation of China(No.21878090)Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan Province(No.2020CL04).
文摘Mixed-valence metallic compounds are a class of functional materials with peculiar electrochemical properties.Exploring the correlation between defects and corrosion resistance of mixed-valence metallic compounds is a novel and interesting subject.Through an intelligently designed synergistic process of reduction and directed assembly,not only the directional generation of oxygen vacancies along the normal direction of the(010)crystal plane was achieved,but also the W_(18)O_(49)mixed-valence metal oxide(MVMO)with a single crystalline phase and an assembled ordered three-dimensional cluster structure of nanorods was obtained.Three attractive effects of oriented oxygen vacancies in W_(18)O_(49)MVMO were discovered.First,the oxygen vacancy channels realized the directional concentrated transport of oxygen atoms to form dense oxide passivation film.Second,the directional concentrated oxygen vacancies as active centers effectively solved the problem of difficult photoelectron leap and separation of pure-phase semiconductors,realizing photogenerated cathodic protection.Third,the high-energy vacancies endowed the material with antibacterial function,which contributed to the stable existence of the anti-corrosion system.The resistance value of W_(18)O_(49)MVMO as an anti-corrosion functional material was increased to more than 4.00 times that of the original metal protection layer.The experimental results obtained in this research were of great reference value for revealing the intrinsic mechanism of correlation between oxygen defect orientation of MVMOs and electrochemistry.
