To improve overall equipment efficiency(OEE) of a semiconductor wafer wet-etching system,a heuristic tabu search scheduling algorithm is proposed for the wet-etching process in the paper,with material handling robot c...To improve overall equipment efficiency(OEE) of a semiconductor wafer wet-etching system,a heuristic tabu search scheduling algorithm is proposed for the wet-etching process in the paper,with material handling robot capacity and wafer processing time constraints of the process modules considered.Firstly,scheduling problem domains of the wet-etching system(WES) are assumed and defined,and a non-linear programming model is built to maximize the throughput with no defective wafers.On the basis of the model,a scheduling algorithm based on tabu search is presented in this paper.An improved Nawaz,Enscore,and Ham(NEH) heuristic algorithm is used as the initial feasible solution of the proposed heuristic algorithm.Finally,performances of the proposed algorithm are analyzed and evaluated by simulation experiments.The results indicate that the proposed algorithm is valid and practical to generate satisfied scheduling solutions.展开更多
Needles,as some of the most widely used medical devices,have been effectively applied in human disease prevention,diagnosis,treatment,and rehabilitation.Thin 1D needle can easily penetrate cells/organs by generating h...Needles,as some of the most widely used medical devices,have been effectively applied in human disease prevention,diagnosis,treatment,and rehabilitation.Thin 1D needle can easily penetrate cells/organs by generating highly localized stress with their sharp tips to achieve bioliquid sampling,biosensing,drug delivery,surgery,and other such applications.In this review,we provide an overview of multiscale needle fabrication techniques and their biomedical applications.Needles are classified as nanoneedles,microneedles and millineedles based on the needle diameter,and their fabrication techniques are highlighted.Nanoneedles bridge the inside and outside of cells,achieving intracellular electrical recording,biochemical sensing,and drug delivery.Microneedles penetrate the stratum corneum layer to detect biomarkers/bioelectricity in interstitial fluid and deliver drugs through the skin into the human circulatory system.Millineedles,including puncture,syringe,acupuncture and suture needles,are presented.Finally,conclusions and future perspectives for next-generation nano/micro/milli needles are discussed.展开更多
Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is p...Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.展开更多
Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined sp...Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined spaces,and millimeter-scale height restrictions,presenting significant challenges to conventional inspection methods.Here,we present an ultrasonic microrobot(weight,80 mg;dimensions,24 mm×7 mm;thickness,210μm)to realize agile and bidirectional navigation in narrow pipelines.The ultrathin structural design of the robot is achieved through a high-performance piezoelectric composite film microstructure based on MEMS technology.The robot exhibits various vibration modes when driven by ultrasonic frequency signals,its motion speed reaches81 cm s-1 at 54.8 k Hz,exceeding that of the fastest piezoelectric microrobots,and its forward and backward motion direction is controllable through frequency modulation,while the minimum driving voltage for initial movement can be as low as 3 VP-P.Additionally,the robot can effortlessly climb slopes up to 24.25°and carry loads more than 36 times its weight.The robot is capable of agile navigation through curved L-shaped pipes,pipes made of various materials(acrylic,stainless steel,and polyvinyl chloride),and even over water.To further demonstrate its inspection capabilities,a micro-endoscope camera is integrated into the robot,enabling real-time image capture inside glass pipes.展开更多
The next-generation RAN,known as Open Radio Access Network(ORAN),allows for several advantages,including cost-effectiveness,network flexibility,and interoperability.Now ORAN applications,utilising machine learning(ML)...The next-generation RAN,known as Open Radio Access Network(ORAN),allows for several advantages,including cost-effectiveness,network flexibility,and interoperability.Now ORAN applications,utilising machine learning(ML)and artificial intelligence(AI)techniques,have become standard practice.The need for Federated Learning(FL)for ML model training in ORAN environments is heightened by the modularised structure of the ORAN architecture and the shortcomings of conventional ML techniques.However,the traditional plaintext model update sharing of FL in multi-BS contexts is susceptible to privacy violations such as deep-leakage gradient assaults and inference.Therefore,this research presents a novel blockchain-assisted improved cryptographic privacy-preserving federated learning(BICPPFL)model,with the help of ORAN,to safely carry out federated learning and protect privacy.This model improves on the conventional masking technique for sharing model parameters by adding new characteristics.These features include the choice of distributed aggregators,validation for final model aggregation,and individual validation for BSs.To manage the security and privacy of FL processes,a combined homomorphic proxy-reencryption(HPReE)and lattice-cryptographic method(HPReEL)has been used.The upgraded delegated proof of stake(Up-DPoS)consensus protocol,which will provide quick validation of model exchanges and protect against malicious attacks,is employed for effective consensus across blockchain nodes.Without sacrificing performance metrics,the BICPPFL model strengthens privacy and adds security layers while facilitating the transfer of sensitive data across several BSs.The framework is deployed on top of a Hyperledger Fabric blockchain to evaluate its effectiveness.The experimental findings prove the reliability and privacy-preserving capability of the BICPPFL model.展开更多
By May 14,confirmed cases of the novel coronavirus disease(COVID-19)in the United States had crossed 1.39 million,with the death toll surpassing 84,000.However,instead of concentrating on fighting the pandemic domesti...By May 14,confirmed cases of the novel coronavirus disease(COVID-19)in the United States had crossed 1.39 million,with the death toll surpassing 84,000.However,instead of concentrating on fighting the pandemic domestically,some U.S.politicians have been fabricating allegations to pin the blame on China and hide their irresponsibility.展开更多
The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution an...The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution and short wavelength.Efficient and compact 193 nm DUV laser source thus becomes a hot research area.Currently,193 nm Ar F excimer gas laser is widely employed in DUV lithography systems and serves as the enabling technology for 7 and 5 nm semiconductor fabrication.展开更多
Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the p...Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the past few years,MXenes/carbon nanotubes(CNTs)-based hybrids have attracted extensive attention as an important catalyst in energy and environmental fields,due to their superior multifunctions and mechanical stability.This review aims to address the fabrication strategies,the identification of the enhancement mechanisms,and recent progress regarding the design and modification of MXenes/CNTs-based hybrids.A myriad of fabrication techniques have been systematically summarized,including mechanical mixing,spray drying,three-dimensional(3D)printing,self-assembly/in-situ growth,freeze drying,templating,hydrothermal methods,chemical vapor deposition(CVD),and rolling.Importantly,the identification of the enhancement mechanisms was thoroughly discussed from the two dimensions of theoretical simulations and in-situ analysis.Moreover,the recent advancements in profound applications of MXenes/CNTs-based hybrids have also been carefully revealed,including energy storage devices,sensors,water purification systems,and microwave absorption.We also underscore anticipated challenges related to their fabrication,structure,underlying mechanisms,modification approaches,and emergent applications.Consequently,this review offers insights into prospective directions and the future trajectory for these promising hybrids.It is expected that this review can inspire new ideas or provide new research methods for future studies.展开更多
Polyelectrolyte porous membranes(PPMs)belong to the most interesting classes of materials,because the synergy of tunable pore sizes and charge nature of polyelectrolyte endow them with wide-ranging practical applicati...Polyelectrolyte porous membranes(PPMs)belong to the most interesting classes of materials,because the synergy of tunable pore sizes and charge nature of polyelectrolyte endow them with wide-ranging practical applications.However,owing to the water solu-bility and ionic nature of the polyelectrolytes,traditional polyelectrolytes are difficult to use in scalable preparation of high-quality PPMs through the well-developed industrial methods.Poly(ionic liquid)s(PIL)are a subclass of functional polyelectrolytes bearing ionic liquid groups in their repeating unites,inheriting the advantages of ionic liquids(ILs)and macromolecular architecture features.In recent years,along with rapid development of PIL materials chemistry,considerable and significant developments involving the novel preparation methods,and structure-property-function relationships of PPMs have been made.In this review,we highlight the latest discovery and proceedings of PPMs,particularly the advancements in how to tailor structures and properties of PPMs by ra-tional structure design of PILs.The formation mechanisms of various PPMs were also discussed in detail from the viewpoint of PILs molecular structures.A future perspective of the challenges and promising potential of PPMs is cast on the basis of these achieve-ments.We expect that these analyses and deductions will be useful for the design of useful PPMs and serve as a source of inspira-tion for the design of future multifunctional PPMs.展开更多
Hyperledger Fabric是一个主流的联盟链平台,当面临多笔并发执行且相互关联的交易时,现有架构容易生成大量无效交易,这严重降低了系统的有效交易处理能力。为了解决这一问题,提出一种融合映射与有向无环图(DAG)的冲突消除机制—FabricIM...Hyperledger Fabric是一个主流的联盟链平台,当面临多笔并发执行且相互关联的交易时,现有架构容易生成大量无效交易,这严重降低了系统的有效交易处理能力。为了解决这一问题,提出一种融合映射与有向无环图(DAG)的冲突消除机制—FabricIMD(Fabric integrated with map and DAG)。该机制在背书节点处通过映射识别交易间依赖关系,并使用有向无环图对此关系进行构建,以调整交易背书顺序,从而有效避免了交易冲突现象的出现。实验证明,当存在多笔相互关联的并发交易时,FabricIMD机制能显著减少因交易冲突导致的无效交易。随着交易间冲突程度的变化,系统有效交易吞吐量提升了15.68%~96.08%。此外,在处理无关联的并发交易时,引入该机制并未对系统性能造成显著影响。综上,FabricIMD机制在避免交易冲突现象出现的同时提高了系统有效交易吞吐量,减少了无效交易数量。展开更多
Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-depo...Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.展开更多
A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580...A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.展开更多
Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of L...Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits,copper foil is required to have demanding properties,such as extremely thin thickness and extremely high tensile strength.This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil,and the effects of process parameters,cathode substrate,and additives on the electrodeposition behavior,microstructure,and properties of copper foil are discussed in detail.Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized,including the formation of nanotwins and texture.Furthermore,the recent advances in novel electrolytic copper foils,such as composite foils and extra-thin copper foils,are also overviewed.Lastly,the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.展开更多
基金Supported by the National Natural Science Foundation of China(No.71071115,61273035)
文摘To improve overall equipment efficiency(OEE) of a semiconductor wafer wet-etching system,a heuristic tabu search scheduling algorithm is proposed for the wet-etching process in the paper,with material handling robot capacity and wafer processing time constraints of the process modules considered.Firstly,scheduling problem domains of the wet-etching system(WES) are assumed and defined,and a non-linear programming model is built to maximize the throughput with no defective wafers.On the basis of the model,a scheduling algorithm based on tabu search is presented in this paper.An improved Nawaz,Enscore,and Ham(NEH) heuristic algorithm is used as the initial feasible solution of the proposed heuristic algorithm.Finally,performances of the proposed algorithm are analyzed and evaluated by simulation experiments.The results indicate that the proposed algorithm is valid and practical to generate satisfied scheduling solutions.
基金National Natural Science Foundation of China(Grant Nos.52175446,51975133,51975597)Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515011740,2019A1515011011)Shenzhen Fundamental Research Program(Grant No.JCYJ20170818163426597).
文摘Needles,as some of the most widely used medical devices,have been effectively applied in human disease prevention,diagnosis,treatment,and rehabilitation.Thin 1D needle can easily penetrate cells/organs by generating highly localized stress with their sharp tips to achieve bioliquid sampling,biosensing,drug delivery,surgery,and other such applications.In this review,we provide an overview of multiscale needle fabrication techniques and their biomedical applications.Needles are classified as nanoneedles,microneedles and millineedles based on the needle diameter,and their fabrication techniques are highlighted.Nanoneedles bridge the inside and outside of cells,achieving intracellular electrical recording,biochemical sensing,and drug delivery.Microneedles penetrate the stratum corneum layer to detect biomarkers/bioelectricity in interstitial fluid and deliver drugs through the skin into the human circulatory system.Millineedles,including puncture,syringe,acupuncture and suture needles,are presented.Finally,conclusions and future perspectives for next-generation nano/micro/milli needles are discussed.
基金supported by National Natural Science Foundation of China(No.52025055 and 52275571)Basic Research Operation Fund of China(No.xzy012024024).
文摘Tilted metasurface nanostructures,with excellent physical properties and enormous application potential,pose an urgent need for manufacturing methods.Here,electric-field-driven generative-nanoimprinting technique is proposed.The electric field applied between the template and the substrate drives the contact,tilting,filling,and holding processes.By accurately controlling the introduced included angle between the flexible template and the substrate,tilted nanostructures with a controllable angle are imprinted onto the substrate,although they are vertical on the template.By flexibly adjusting the electric field intensity and the included angle,large-area uniform-tilted,gradient-tilted,and high-angle-tilted nanostructures are fabricated.In contrast to traditional replication,the morphology of the nanoimprinting structure is extended to customized control.This work provides a cost-effective,efficient,and versatile technology for the fabrication of various large-area tilted metasurface structures.As an illustration,a tilted nanograting with a high coupling efficiency is fabricated and integrated into augmented reality displays,demonstrating superior imaging quality.
基金supported by the National Key Research and Development Program of China(No.2024YFB3212901)National Natural Science Foundation of China(12072189)the Medicine and Engineering Interdisciplinary Research Fund of Shanghai Jiao Tong University(No.YG2025ZD05)。
文摘Pipelines are extensively used in environments such as nuclear power plants,chemical factories,and medical devices to transport gases and liquids.These tubular environments often feature complex geometries,confined spaces,and millimeter-scale height restrictions,presenting significant challenges to conventional inspection methods.Here,we present an ultrasonic microrobot(weight,80 mg;dimensions,24 mm×7 mm;thickness,210μm)to realize agile and bidirectional navigation in narrow pipelines.The ultrathin structural design of the robot is achieved through a high-performance piezoelectric composite film microstructure based on MEMS technology.The robot exhibits various vibration modes when driven by ultrasonic frequency signals,its motion speed reaches81 cm s-1 at 54.8 k Hz,exceeding that of the fastest piezoelectric microrobots,and its forward and backward motion direction is controllable through frequency modulation,while the minimum driving voltage for initial movement can be as low as 3 VP-P.Additionally,the robot can effortlessly climb slopes up to 24.25°and carry loads more than 36 times its weight.The robot is capable of agile navigation through curved L-shaped pipes,pipes made of various materials(acrylic,stainless steel,and polyvinyl chloride),and even over water.To further demonstrate its inspection capabilities,a micro-endoscope camera is integrated into the robot,enabling real-time image capture inside glass pipes.
文摘The next-generation RAN,known as Open Radio Access Network(ORAN),allows for several advantages,including cost-effectiveness,network flexibility,and interoperability.Now ORAN applications,utilising machine learning(ML)and artificial intelligence(AI)techniques,have become standard practice.The need for Federated Learning(FL)for ML model training in ORAN environments is heightened by the modularised structure of the ORAN architecture and the shortcomings of conventional ML techniques.However,the traditional plaintext model update sharing of FL in multi-BS contexts is susceptible to privacy violations such as deep-leakage gradient assaults and inference.Therefore,this research presents a novel blockchain-assisted improved cryptographic privacy-preserving federated learning(BICPPFL)model,with the help of ORAN,to safely carry out federated learning and protect privacy.This model improves on the conventional masking technique for sharing model parameters by adding new characteristics.These features include the choice of distributed aggregators,validation for final model aggregation,and individual validation for BSs.To manage the security and privacy of FL processes,a combined homomorphic proxy-reencryption(HPReE)and lattice-cryptographic method(HPReEL)has been used.The upgraded delegated proof of stake(Up-DPoS)consensus protocol,which will provide quick validation of model exchanges and protect against malicious attacks,is employed for effective consensus across blockchain nodes.Without sacrificing performance metrics,the BICPPFL model strengthens privacy and adds security layers while facilitating the transfer of sensitive data across several BSs.The framework is deployed on top of a Hyperledger Fabric blockchain to evaluate its effectiveness.The experimental findings prove the reliability and privacy-preserving capability of the BICPPFL model.
文摘By May 14,confirmed cases of the novel coronavirus disease(COVID-19)in the United States had crossed 1.39 million,with the death toll surpassing 84,000.However,instead of concentrating on fighting the pandemic domestically,some U.S.politicians have been fabricating allegations to pin the blame on China and hide their irresponsibility.
基金supported by the National Natural Science Foundation of China(Grant Nos.62450006,62304217,62274157,62127807,62234011,62034008,62074142,62074140)Tianshan Innovation Team Program(Grant No.2022TSYCTD0005)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0880000)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant Nos.2023124,Y2023032)。
文摘The 193 nm deep-ultraviolet(DUV)laser plays a critical role in advanced semiconductor chip manufacturing[1,2],micro-nano material characterization[3,4]and biomedical analysis[5,6],due to its high spatial resolution and short wavelength.Efficient and compact 193 nm DUV laser source thus becomes a hot research area.Currently,193 nm Ar F excimer gas laser is widely employed in DUV lithography systems and serves as the enabling technology for 7 and 5 nm semiconductor fabrication.
基金supported by the National Natural Science Foundation of China(No.62004143)the Key R&D Program of Hubei Province(No.2022BAA084).
文摘Emerging two-dimensional(2D)layered metal carbide and nitride materials,commonly termed MXenes,are increasingly recognized for their applications across diverse fields such as energy,environment,and catalysis.In the past few years,MXenes/carbon nanotubes(CNTs)-based hybrids have attracted extensive attention as an important catalyst in energy and environmental fields,due to their superior multifunctions and mechanical stability.This review aims to address the fabrication strategies,the identification of the enhancement mechanisms,and recent progress regarding the design and modification of MXenes/CNTs-based hybrids.A myriad of fabrication techniques have been systematically summarized,including mechanical mixing,spray drying,three-dimensional(3D)printing,self-assembly/in-situ growth,freeze drying,templating,hydrothermal methods,chemical vapor deposition(CVD),and rolling.Importantly,the identification of the enhancement mechanisms was thoroughly discussed from the two dimensions of theoretical simulations and in-situ analysis.Moreover,the recent advancements in profound applications of MXenes/CNTs-based hybrids have also been carefully revealed,including energy storage devices,sensors,water purification systems,and microwave absorption.We also underscore anticipated challenges related to their fabrication,structure,underlying mechanisms,modification approaches,and emergent applications.Consequently,this review offers insights into prospective directions and the future trajectory for these promising hybrids.It is expected that this review can inspire new ideas or provide new research methods for future studies.
基金We greatly acknowledge the financial supports by the National Natural Science Foundation of China(Grant No.21875119)the Natural Science Foundation of Tianjin City(Grant Nos.19JCYBJC17500,21JCZDJC00250)the National Programfor Support of Top-notch Young Professionals。
文摘Polyelectrolyte porous membranes(PPMs)belong to the most interesting classes of materials,because the synergy of tunable pore sizes and charge nature of polyelectrolyte endow them with wide-ranging practical applications.However,owing to the water solu-bility and ionic nature of the polyelectrolytes,traditional polyelectrolytes are difficult to use in scalable preparation of high-quality PPMs through the well-developed industrial methods.Poly(ionic liquid)s(PIL)are a subclass of functional polyelectrolytes bearing ionic liquid groups in their repeating unites,inheriting the advantages of ionic liquids(ILs)and macromolecular architecture features.In recent years,along with rapid development of PIL materials chemistry,considerable and significant developments involving the novel preparation methods,and structure-property-function relationships of PPMs have been made.In this review,we highlight the latest discovery and proceedings of PPMs,particularly the advancements in how to tailor structures and properties of PPMs by ra-tional structure design of PILs.The formation mechanisms of various PPMs were also discussed in detail from the viewpoint of PILs molecular structures.A future perspective of the challenges and promising potential of PPMs is cast on the basis of these achieve-ments.We expect that these analyses and deductions will be useful for the design of useful PPMs and serve as a source of inspira-tion for the design of future multifunctional PPMs.
文摘Hyperledger Fabric是一个主流的联盟链平台,当面临多笔并发执行且相互关联的交易时,现有架构容易生成大量无效交易,这严重降低了系统的有效交易处理能力。为了解决这一问题,提出一种融合映射与有向无环图(DAG)的冲突消除机制—FabricIMD(Fabric integrated with map and DAG)。该机制在背书节点处通过映射识别交易间依赖关系,并使用有向无环图对此关系进行构建,以调整交易背书顺序,从而有效避免了交易冲突现象的出现。实验证明,当存在多笔相互关联的并发交易时,FabricIMD机制能显著减少因交易冲突导致的无效交易。随着交易间冲突程度的变化,系统有效交易吞吐量提升了15.68%~96.08%。此外,在处理无关联的并发交易时,引入该机制并未对系统性能造成显著影响。综上,FabricIMD机制在避免交易冲突现象出现的同时提高了系统有效交易吞吐量,减少了无效交易数量。
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0609000)National Natural Science Foundation of China(Grant Nos.52171034 and 52101037)Postdoctoral Fellowship Program of CPSFara(No.GZB20230944).
文摘Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.
基金supported by the National Natural Science Foundation of China(Nos.51825101,52001202)the National Key Research and Development Program of China(No.2021YFA1600900)。
文摘A comprehensive analysis of the microstructure and defects of a thixomolded AZ91D alloy was conducted to elucidate their influences on mechanical properties.Samples were made at injection temperatures ranging from 580 to 640℃.X-ray computed tomography was used to visualize pores,and crystal plasticity finite element simulation was adopted for deformation analysis.The microstructure characterizations reveal a hierarchical cell feature composed of α-Mg and eutectic phases.With the increase of injection temperature,large cell content in the material decreases,while the strength of the alloy increases.The underlying mechanism about strength change is that coarse-grained solids experience smaller stress even in hard orientations.The sample fabricated at a moderate temperature of 620℃ exhibits the highest elongation,least quantity and lower local concentration of pores.The detachment and tearing cracks formed at lower injection temperature and defect bands formed at higher injection temperature add additional crack sources and deteriorate the ductility of the materials.
基金supported by the National Key R&D Plan Program of China(No.2021YFB3400800)Henan Key Research and Development Program(No.231111241000)+1 种基金the Joint Fund of Henan Province Science and Technology R&D Program(No.225200810026)Zhongyuan Scholar Workstation Funded Program(No.224400510025).
文摘Electrolytic copper foil has gained significant attention as an essential component in lithium-ion batteries(LIBs),printed circuit boards(PCBs),and chip packaging substrates(CPSs)applications.With the advancement of LIBs towards higher energy densities and the increasing density of electronic components on circuits,copper foil is required to have demanding properties,such as extremely thin thickness and extremely high tensile strength.This comprehensive review firstly summarizes recent progress on the fabrication of electrolytic copper foil,and the effects of process parameters,cathode substrate,and additives on the electrodeposition behavior,microstructure,and properties of copper foil are discussed in detail.Then the regulation strategies of mechanical properties of electrolytic copper foil are also summarized,including the formation of nanotwins and texture.Furthermore,the recent advances in novel electrolytic copper foils,such as composite foils and extra-thin copper foils,are also overviewed.Lastly,the remaining challenges and perspectives on the further development of electrolytic copper foils are presented.
