Due to the disturbances of spatters, dusts and strong arc light, it is difficult to detect the molten pool edge and the weld line location in CO_2 welding processes. The median filtering and self-multiplication was em...Due to the disturbances of spatters, dusts and strong arc light, it is difficult to detect the molten pool edge and the weld line location in CO_2 welding processes. The median filtering and self-multiplication was employed to preprocess the image of the CO_2 welding in order to detect effectively the edge of molten pool and the location of weld line. The B-spline wavelet algorithm has been investigated, the influence of different scales and thresholds on the results of the edge detection have been compared and analyzed. The experimental results show that better performance to extract the edge of the molten pool and the location of weld line can be obtained by using the B-spline wavelet transform. The proposed edge detection approach can be further applied to the control of molten depth and the seam tracking.展开更多
The mechanisms of weld formation, spatter and projected transfer in CO2 arc welding are revealed based on the experiment and study of the arc physics. The views are beneficial to develop CO2 arc welding technology.
A micro shear testing method which can suit to measure the mechanical properties of heterogeneous materials is introduced, and the properties in each zone of welded joint for CO2 arc welding can be evaluated by using ...A micro shear testing method which can suit to measure the mechanical properties of heterogeneous materials is introduced, and the properties in each zone of welded joint for CO2 arc welding can be evaluated by using this method in this paper. Moreover, these results are compared with those results of Charpy V-notch impact test and their correlation is discussed.展开更多
In the automatic CO_2 arc welding, the alteration of the vertical distance between the welding torch and the workpiece has a strong effect on the welding parameters such as welding current and voltage, with the result...In the automatic CO_2 arc welding, the alteration of the vertical distance between the welding torch and the workpiece has a strong effect on the welding parameters such as welding current and voltage, with the result that the appearance and quality of weld are not steady. To weaken the influence of the distance alteration, a method is put forward in the paper. The method is that the alternate wire-feed control is used for compensating the welding current. On the basis of theoretical analysis, a static numerical model for alternate wire-feed control is established. The experiments show that the model-based regulation of the wire feed rate can compensate the welding current and ensure the appearance of weld. When the alteration of vertical distance between the torch and the workpiece is greater, not only is the wire feed rate regulated, but the output voltage of the power source is adjusted to ensure the appearance and quality of weld.展开更多
Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amo...Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amount of data.However,a unified understanding of underlying mechanism for further optimization is still lacking.In this work,combining first-principles calculations and machine learning(ML)techniques,we elucidate critical factors influencing the catalytic properties,taking Cu-based single atom alloys(SAAs)as examples.Our method relies on high-throughput calculations of 2669 CO adsorption configurations on 43 types of Cu-based SAAs with various surfaces.Extensive ML analyses reveal that low generalized coordination numbers and valence electron number are key features to determine catalytic performance.Applying our ML model with cross-group learning scheme,we demonstrate the model generalizes well between Cu-based SAAs with different alloying elements.Further,electronic structure calculations suggest surface negative center could enhance CO adsorption by back donating electrons to antibonding orbitals of CO.Finally,several SAAs,including PCu,AgCu,GaCu,ZnCu,SnCu,GeCu,InCu,and SiCu,are identified as promising CO_(2)RR catalysts.Our work provides a paradigm for the rational design and fast screening of SAAs for various electrocatalytic reactions.展开更多
The global concerns of energy crisis and climate change,primarily caused by carbon dioxide(CO_(2)),are of utmost importance.Recently,the electrocatalytic CO_(2) reduction reaction(CO_(2)RR) to high value-added multi-c...The global concerns of energy crisis and climate change,primarily caused by carbon dioxide(CO_(2)),are of utmost importance.Recently,the electrocatalytic CO_(2) reduction reaction(CO_(2)RR) to high value-added multi-carbon(C_(2+)) products driven by renewable electricity has emerged as a highly promising solution to alleviate energy shortages and achieve carbon neutrality.Among these C_(2+) products,ethylene(C_(2)H_(4))holds particular importance in the petrochemical industry.Accordingly,this review aims to establish a connection between the fundamentals of electrocatalytic CO_(2) reduction reaction to ethylene(CO_(2)RRto-C_(2)H_(4)) in laboratory-scale research(lab) and its potential applications in industrial-level fabrication(fab).The review begins by summarizing the fundamental aspects,including the design strategies of high-performance Cu-based electrocatalysts and advanced electrolyzer devices.Subsequently,innovative and value-added techniques are presented to address the inherent challenges encountered during the implementations of CO_(2)RR-to-C_(2)H_(4) in industrial scenarios.Additionally,case studies of the technoeconomic analysis of the CO_(2)RR-to-C_(2)H_(4) process are discussed,taking into factors such as costeffectiveness,scalability,and market potential.The review concludes by outlining the perspectives and challenges associated with scaling up the CO_(2)RR-to-C_(2)H_(4) process.The insights presented in this review are expected to make a valuable contribution in advancing the CO_(2)RR-to-C_(2)H_(4) process from lab to fab.展开更多
Rational design of ionic liquids(ILs),which is highly dependent on the accuracy of the model used,has always been crucial for CO_(2)separation from flue gas.In this study,a support vector machine(SVM)model which is a ...Rational design of ionic liquids(ILs),which is highly dependent on the accuracy of the model used,has always been crucial for CO_(2)separation from flue gas.In this study,a support vector machine(SVM)model which is a machine learning approach is established,so as to improve the prediction accuracy and range of IL melting points.Based on IL melting points data with 600 training data and 168 testing data,the estimated average absolute relative deviations(AARD)and squared correlation coefficients(R^(2))are 3.11%,0.8820 and 5.12%,0.8542 for the training set and testing set of the SVM model,respectively.Then,through the melting points model and other rational design processes including conductor-like screening model for real solvents(COSMO-RS)calculation and physical property constraints,cyano-based ILs are obtained,in which tetracyanoborate[TCB]-is often ruled out due to incorrect estimation of melting points model in the literature.Subsequently,by means of process simulation using Aspen Plus,optimal IL are compared with excellent IL reported in the literature.Finally,1-ethyl-3-methylimidazolium tricyanomethanide[EMIM][TCM]is selected as a most suitable solvent for CO_(2)separation from flue gas,the process of which leads to 12.9%savings on total annualized cost compared to that of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide[EMIM][Tf_(2)N].展开更多
The COarc welding was carried out under a longitudinal magnetic field,and the arc shape has been studied by using a high-speed camera.From the camera images,we know that under the action of the longitudinal magnetic f...The COarc welding was carried out under a longitudinal magnetic field,and the arc shape has been studied by using a high-speed camera.From the camera images,we know that under the action of the longitudinal magnetic field,the upper end of the arc will constrict and the lower end of the arc will expand.It would become a bell-type shape and rotate at a highspeed in the optimum range of magnetic field parameters.The arc shape was simulated using a mathematical model,which was established based on experiment data and theoretical knowledge,and mechanism analysis has been carried out regarding the effect of longitudinal magnetic field on COwelding arcs.展开更多
Arc welding robot is playing more and more important roles in modern welding manufacturing, but now available welding power sources seldom satisfy with robot system requirements. In this paper, study on fuzzy control ...Arc welding robot is playing more and more important roles in modern welding manufacturing, but now available welding power sources seldom satisfy with robot system requirements. In this paper, study on fuzzy control IGBT inverter arc welding power source for robot is developed to bring robotic advantages into full play. Firstly, fast response 500A IGBT inverter arc welding rectifier is developed. Secondly, fuzzy control system, which features multi-functions, fast response and wide using range, is developed and reliable measures for preventing interference are designed. Finally, technological experiments for carbon steel are made. The welding experimental results show that the goal of design is attained.展开更多
文摘Due to the disturbances of spatters, dusts and strong arc light, it is difficult to detect the molten pool edge and the weld line location in CO_2 welding processes. The median filtering and self-multiplication was employed to preprocess the image of the CO_2 welding in order to detect effectively the edge of molten pool and the location of weld line. The B-spline wavelet algorithm has been investigated, the influence of different scales and thresholds on the results of the edge detection have been compared and analyzed. The experimental results show that better performance to extract the edge of the molten pool and the location of weld line can be obtained by using the B-spline wavelet transform. The proposed edge detection approach can be further applied to the control of molten depth and the seam tracking.
文摘The mechanisms of weld formation, spatter and projected transfer in CO2 arc welding are revealed based on the experiment and study of the arc physics. The views are beneficial to develop CO2 arc welding technology.
文摘A micro shear testing method which can suit to measure the mechanical properties of heterogeneous materials is introduced, and the properties in each zone of welded joint for CO2 arc welding can be evaluated by using this method in this paper. Moreover, these results are compared with those results of Charpy V-notch impact test and their correlation is discussed.
文摘In the automatic CO_2 arc welding, the alteration of the vertical distance between the welding torch and the workpiece has a strong effect on the welding parameters such as welding current and voltage, with the result that the appearance and quality of weld are not steady. To weaken the influence of the distance alteration, a method is put forward in the paper. The method is that the alternate wire-feed control is used for compensating the welding current. On the basis of theoretical analysis, a static numerical model for alternate wire-feed control is established. The experiments show that the model-based regulation of the wire feed rate can compensate the welding current and ensure the appearance of weld. When the alteration of vertical distance between the torch and the workpiece is greater, not only is the wire feed rate regulated, but the output voltage of the power source is adjusted to ensure the appearance and quality of weld.
基金supported by the National Natural Science Foundation of China (Grant Nos.62006219 and 62001266)Guangdong Innovative and Entrepre-neurial Research Team Program (grant No.2017ZT07C341)+2 种基金the Bureau of Industry and Information Technology of Shenzhen for the 2017 Graphene Manufacturing Innovation Center Project (No.201901171523)the China Postdoctoral Science Foundation (No.2020M680506)Guangdong Basic and Applied Basic Research Foundation (No.2020A1515110338).
文摘Various strategies,including controls of morphology,oxidation state,defect,and doping,have been developed to improve the performance of Cu-based catalysts for CO_(2) reduction reaction(CO_(2)RR),generating a large amount of data.However,a unified understanding of underlying mechanism for further optimization is still lacking.In this work,combining first-principles calculations and machine learning(ML)techniques,we elucidate critical factors influencing the catalytic properties,taking Cu-based single atom alloys(SAAs)as examples.Our method relies on high-throughput calculations of 2669 CO adsorption configurations on 43 types of Cu-based SAAs with various surfaces.Extensive ML analyses reveal that low generalized coordination numbers and valence electron number are key features to determine catalytic performance.Applying our ML model with cross-group learning scheme,we demonstrate the model generalizes well between Cu-based SAAs with different alloying elements.Further,electronic structure calculations suggest surface negative center could enhance CO adsorption by back donating electrons to antibonding orbitals of CO.Finally,several SAAs,including PCu,AgCu,GaCu,ZnCu,SnCu,GeCu,InCu,and SiCu,are identified as promising CO_(2)RR catalysts.Our work provides a paradigm for the rational design and fast screening of SAAs for various electrocatalytic reactions.
基金supported by Zhejiang Provincial Department of Science and Technology under its Provincial Key Laboratory Program(2020E10018)the financial support from Fundamental Research Funds for the Central Universities(2022LHJH01-03,2022ZFJH04,2022QZJH14)+5 种基金Pioneer R&D Program of Zhejiang Province(2022C03040)the financial aid from National Natural Science Foundation of China(22005266)Zhejiang Provincial Natural Science Foundation(LR21E020003)Fundamental Research Funds for the Central Universities(2021FZZX001-09)supported by the Royal Academy of Engineering under the Chairs in Emerging Technologies scheme(CiET2021_17)University of Nottingham Ningbo China for providing a full PhD scholarship。
文摘The global concerns of energy crisis and climate change,primarily caused by carbon dioxide(CO_(2)),are of utmost importance.Recently,the electrocatalytic CO_(2) reduction reaction(CO_(2)RR) to high value-added multi-carbon(C_(2+)) products driven by renewable electricity has emerged as a highly promising solution to alleviate energy shortages and achieve carbon neutrality.Among these C_(2+) products,ethylene(C_(2)H_(4))holds particular importance in the petrochemical industry.Accordingly,this review aims to establish a connection between the fundamentals of electrocatalytic CO_(2) reduction reaction to ethylene(CO_(2)RRto-C_(2)H_(4)) in laboratory-scale research(lab) and its potential applications in industrial-level fabrication(fab).The review begins by summarizing the fundamental aspects,including the design strategies of high-performance Cu-based electrocatalysts and advanced electrolyzer devices.Subsequently,innovative and value-added techniques are presented to address the inherent challenges encountered during the implementations of CO_(2)RR-to-C_(2)H_(4) in industrial scenarios.Additionally,case studies of the technoeconomic analysis of the CO_(2)RR-to-C_(2)H_(4) process are discussed,taking into factors such as costeffectiveness,scalability,and market potential.The review concludes by outlining the perspectives and challenges associated with scaling up the CO_(2)RR-to-C_(2)H_(4) process.The insights presented in this review are expected to make a valuable contribution in advancing the CO_(2)RR-to-C_(2)H_(4) process from lab to fab.
基金the financial support by the National Natural Science Foundation of China(Project No.21878054)the Natural Science Foundation of Fujian Province of China(2020J01515)
文摘Rational design of ionic liquids(ILs),which is highly dependent on the accuracy of the model used,has always been crucial for CO_(2)separation from flue gas.In this study,a support vector machine(SVM)model which is a machine learning approach is established,so as to improve the prediction accuracy and range of IL melting points.Based on IL melting points data with 600 training data and 168 testing data,the estimated average absolute relative deviations(AARD)and squared correlation coefficients(R^(2))are 3.11%,0.8820 and 5.12%,0.8542 for the training set and testing set of the SVM model,respectively.Then,through the melting points model and other rational design processes including conductor-like screening model for real solvents(COSMO-RS)calculation and physical property constraints,cyano-based ILs are obtained,in which tetracyanoborate[TCB]-is often ruled out due to incorrect estimation of melting points model in the literature.Subsequently,by means of process simulation using Aspen Plus,optimal IL are compared with excellent IL reported in the literature.Finally,1-ethyl-3-methylimidazolium tricyanomethanide[EMIM][TCM]is selected as a most suitable solvent for CO_(2)separation from flue gas,the process of which leads to 12.9%savings on total annualized cost compared to that of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide[EMIM][Tf_(2)N].
基金supported by National Natural Science Foundation of China(No.51275314)the Program of Science and Technology Foundation of Shenyang,China(F13-316-1-04)
文摘The COarc welding was carried out under a longitudinal magnetic field,and the arc shape has been studied by using a high-speed camera.From the camera images,we know that under the action of the longitudinal magnetic field,the upper end of the arc will constrict and the lower end of the arc will expand.It would become a bell-type shape and rotate at a highspeed in the optimum range of magnetic field parameters.The arc shape was simulated using a mathematical model,which was established based on experiment data and theoretical knowledge,and mechanism analysis has been carried out regarding the effect of longitudinal magnetic field on COwelding arcs.
文摘Arc welding robot is playing more and more important roles in modern welding manufacturing, but now available welding power sources seldom satisfy with robot system requirements. In this paper, study on fuzzy control IGBT inverter arc welding power source for robot is developed to bring robotic advantages into full play. Firstly, fast response 500A IGBT inverter arc welding rectifier is developed. Secondly, fuzzy control system, which features multi-functions, fast response and wide using range, is developed and reliable measures for preventing interference are designed. Finally, technological experiments for carbon steel are made. The welding experimental results show that the goal of design is attained.
