In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production....In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production.Achieving satellite mass assembly is the key to realizing satellite mass production.To this end,satellite manufacturers are working to construct the satellite mass assembly shop-floor(SMAS)to enable moving assembly.However,there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS,as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances.Therefore,this paper proposes a digital twin-based production-logistics synchronization system(DT-PLSS)for SMAS.The framework of DT-PLSS is introduced first.In this framework,DT-PLSS can achieve modular construction,as well as distributed management and control.Based on the proposed framework,the construction methods of resource level digital twin(DT),workstation level DT,and shop-floor level DT in SMAS are discussed.The DT-based disturbance detection method for SMAS is presented,aiming to detect or predict di erent types of disturbances and to analyze the e ect of disturbances.Then,a DT enhanced production-logistics synchronization mechanism for SMAS is proposed.With this mechanism,the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized.Finally,a case study in a real SMAS verifies the feasibility and e ectiveness of the proposed system and methods.This research proposes a practical framework and system which could realize disturbance detection,logistics distribution,and the production-logistics synchronization in complex SMAS scenario e ectively.展开更多
In recent years,as a promising way to realize digital transformation,digital twin shop-floor(DTS)plays an impor-tant role in smart manufacturing.The core feature of DTS is the synchronization.How to implement and main...In recent years,as a promising way to realize digital transformation,digital twin shop-floor(DTS)plays an impor-tant role in smart manufacturing.The core feature of DTS is the synchronization.How to implement and maintain the synchronization is critical for DTS.However,there is still a lack of a common definition for synchronization in DTS.Besides,a systematic synchronization mechanism for DTS is strongly needed.This paper first summarizes the defi-nition and requirements of synchronization in DTS,to clarify the understanding of synchronization in DTS.Then,a 5M synchronization mechanism for DTS is proposed,where 5M refers to multi-system data,multi-fidelity model,multi-resource state,multi-level state,and multi-stage operation.As a bottom-up synchronization mechanism,5M synchronization mechanism for DTS has the potential to support DTS to achieve and maintain physical-virtual state synchronization,and to realize operation synchronization of DTS.The implementation methods of 5M synchronization mechanism for DTS are also introduced.Finally,the proposed synchronization mechanism is validated in a digital twin satellite assembly shop-floor,which proves the effectiveness and feasibility of the mechanism.展开更多
The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell...The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell on the surface of the Ag nanowires and cause atomic contact to promote the diffusion and nanojoining at the Ag and Au interface. Severe slip bands were observed in the Ag nanowires after the deformation. A metallic bond was formed at the interface, with the Ag diffusing into the Au more than the Au diffused into the Ag. This nanoscale wire bonding might present opportunities for nanoscale packaging and nanodevice design.展开更多
Digital twin is currently undergoing a significant transformation from the conceptual and theoretical research phase to the implementation and application phase.However,a universally adaptable research and development...Digital twin is currently undergoing a significant transformation from the conceptual and theoretical research phase to the implementation and application phase.However,a universally adaptable research and development platform for digital twin is critically needed to meet the development requirements.Specifically,a publicly accessible simulation,testing,and validation platform which can support digital twin model building,data processing,algorithm design,configuration,etc.,is urgently required for researchers.Furthermore,for developers from the industry,a lowcode development platform that can offer a customizable suite of functions such as model creation,data management,protocol configuration,and visualization is urgently needed.Meanwhile,for enterprise users,there is a lack of an application management platform that can be configured and migrated for various application scenarios,functions,and modes.Therefore,based on the system research of digital twin theories and key technologies by the authors(such as the five-dimension digital twin model,digital twin modeling and digital twin data theory,digital twin standards,and so on),a digital twin software platform reference architecture,namely make Twin,is proposed and designed,as well as its ten core functions.The workflow of the make Twin and the interaction mechanisms among its core functions are described.Finally,a digital twin application system for a chemical fiber textile shop floor(CFTS)which was developed according to make Twin,is introduced,which validates the proposed reference architecture.展开更多
Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER ...Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER catalytic activity of the single-atom catalysts(SACs)composed of 4d/5d period transition metal(TM)atoms embedded on MBene substrates(TM-M_(2)B_(2)O_(2),M=Ti,Mo,and W).We found that TM dominates the catalytic activity compared to the MBene substrates.The SACs embedded with Rh,Pd,Au,and Ir exhibit excellent ORR or OER catalytic activity.Specifically,Rh-Mo2B2O2and Rh-W2B2O2are promising bifunctional catalysts with ultra-low ORR/OER overpotentials of 0.39/0.21 V and0.19/0.32 V,respectively,lower than that of Pt/RuO_(2)(0.45/0.42 V).Importantly,through machine learning,the models containing 10 element features of SACs were developed to quickly and accurately identify the superior ORR and OER electrocatalysts.Our findings provide several promising SACs for ORR and OER,and offer effective models for catalyst design.展开更多
The planar Hall effect(PHE),which originates from anisotropic magnetoresistance,presents a qualitative and simple approach to characterize electronic structures of quantum materials by applying an in-plane rotating ma...The planar Hall effect(PHE),which originates from anisotropic magnetoresistance,presents a qualitative and simple approach to characterize electronic structures of quantum materials by applying an in-plane rotating magnetic field to induce identical oscillations in both longitudinal and transverse resistances.In this review,we focus on the recent research on the PHE in various quantum materials,including ferromagnetic materials,topological insulators,Weyl semimetals,and orbital anisotropic matters.Firstly,we briefly introduce the family of Hall effect and give a basic deduction of PHE formula with the second-order resistance tensor,showing the mechanism of the characteristicπ-period oscillation in trigonometric function form with aπ/4 phase delay between the longitudinal and transverse resistances.Then,we will introduce the four main mechanisms to realize PHE in quantum materials.After that,the origin of the anomalous planar Hall effect(APHE)results,of which the curve shapes deviate from that of PHE,will be reviewed and discussed.Finally,the challenges and prospects for this field of study are discussed.展开更多
This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing...This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.展开更多
Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in mate...Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively investigated.It is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials.展开更多
Maintenance of aero-engine fleets is crucial for the efficiency,safety,and reliability of the aviation industry.With the increasing demand for air transportation,maintaining high-performing aero-engines has become sig...Maintenance of aero-engine fleets is crucial for the efficiency,safety,and reliability of the aviation industry.With the increasing demand for air transportation,maintaining high-performing aero-engines has become significant.Collaborative maintenance,specifically targeting aero-engine fleets,involves the coordination of multiple tasks and resources to enhance management efficiency and reduce costs.Digital Twin(DT)technology provides essential technical support for the intelligent operation and maintenance of aero-engine fleets.DT maps physical object properties to the virtual world,creating high-fidelity,dynamic models.However,DT-enhanced collaborative maintenance faces various challenges,including the construction of complex system-layer DT models,management of massive integrated DT data,and the development of fusion mechanisms and decision-making methods for DT data and models.Overcoming these challenges will allow the aviation industry to optimize aero-engine fleet maintenance,ensuring safety,efficiency,and cost-effectiveness while meeting the growing demand for air transportation.展开更多
Cavefish, with sensitive lateral lines, can swim freely and locate preys in invisible and complex cave environments, though their eyes are greatly degenerated. Investigations on the morphology and distribution charact...Cavefish, with sensitive lateral lines, can swim freely and locate preys in invisible and complex cave environments, though their eyes are greatly degenerated. Investigations on the morphology and distribution characteristics of their lateral line systems would benefit our understanding of the high-sensitivity mechanism of the fish. In this study, the arrangement and morphology of the lateral lines are described for two species ofSinocyclocheilus： S. macrophthalmus and S. microphthalmus, which live in the karst caves in Guangxi, China. The behavior experiments indicate that the lateral line system of the S. macrophthalmus is more sensitive at a low vibration frequency range from 20 Hz to 70 Hz. The cephalic and trunk lateral line systems both contribute to the efficient object-locating capability. For both of the two species of cavefish, the diameter of the lateral canal nearby the neuromasts is narrower than that nearby the canal pores. This variation can increase the normal pressure to the surface of the cupula, and increase the sensitivity of the canal lateral line system.展开更多
Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be eff...Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be efficiently utilized in many applications. However, these thermoresponsive hydrogels mostly cannot recover their mechanical states under large strain during the process. Herein, we utilize the heterogeneous comb-type polymer network with semicrystalline hydrophobic side chains to design self-recovery semi-crystalline hydrogels. Based on hydrophilic/hydrophobic cooperative complementary interaction and heterogeneous polymer network, hydrogels can be endowed with excellent thermosensitive properties and mechanical performance. The hydrogels exhibit high compressive strength(7.57 MPa) and compressive modulus(1.76 MPa) due to the semi-crystalline domains formed by association of the hydrophobic poly(ε-caprolactone) PCL. The melting-crystalline transition of PCL and elastic polymer network provide the hydrogels excellent thermomechanical performance and self-recovery property. Furthermore, the hydrogels exhibit shape memory behavior, which can be realized by simple process and smart surface patterning. With these excellent properties, our hydrogels can be applied in sensors, flexible devices and scaffolds for tissue engineering.展开更多
Layered IV-V-VI semiconductors have immense potential for thermoelectric(TE)applications due to their intrinsically ultralow lattice thermal conductivity.However,it is extremely difficult to assess their TE performanc...Layered IV-V-VI semiconductors have immense potential for thermoelectric(TE)applications due to their intrinsically ultralow lattice thermal conductivity.However,it is extremely difficult to assess their TE performance via experimental trial-and-error methods.Here,we present a machine-learning-based approach to accelerate the discovery of promising thermoelectric candidates in this chalcogenide family.Based on a dataset generated from high-throughput ab initio calculations,we develop two highly accurateand-efficient neural network models to predict the maximum ZT(ZT_(max))and corresponding doping type,respectively.The top candidate,n-type Pb_(2)Sb_(2)S_(5),is successfully identified,with the ZT_(max) over 1.0 at 650 K,owing to its ultralow thermal conductivity and decent power factor.Besides,we find that n-type Te-based compounds exhibit a combination of high Seebeck coefficient and electrical conductivity,thereby leading to better TE performance under electron doping than hole doping.Whereas p-type TE performance of Se-based semiconductors is superior to n-type,resulting from large Seebeck coefficient induced by high density-ofstates near valence band edges.展开更多
Binary cooperative complementary materials,consisting of two components with entirely opposite physiochemical properties at the nanoscale, are presented as a novel principle for the design and construct of functional ...Binary cooperative complementary materials,consisting of two components with entirely opposite physiochemical properties at the nanoscale, are presented as a novel principle for the design and construct of functional materials. By summarizing recent achievement in materials science, it can be found that the cooperative interaction distance between the pair of complementary property must be comparable with the scale of related physical or chemical parameter. When the binary components are in the cooperative distance, the cooperation between these building blocks becomes dominant and endows the macroscopic materials with unique properties and advanced functionalities that cannot be achieved by either of building blocks.展开更多
A facile in situ redox strategy has been developed to fabricate surfactant-free M-Fe_2O_3(M = Pt, Pd, Au) hybrid nanospheres. In this process, noble metal salts were directly reduced by the pre-prepared Fe_3O_4 compon...A facile in situ redox strategy has been developed to fabricate surfactant-free M-Fe_2O_3(M = Pt, Pd, Au) hybrid nanospheres. In this process, noble metal salts were directly reduced by the pre-prepared Fe_3O_4 components in an alkaline aqueous solution without using organic reductants and surfactants. During the redox reaction, Fe_3O_4 was oxidized into Fe_2O_3,and the reduzates of noble metal nanoparticles were deposited on the surface of the Fe_2O_3 nanospheres. Then the characterizations were discussed in detail to study the formation of M-Fe_2O_3 hybrids. At last, catalytic CO oxidation was selected as a model reaction to evaluate the catalytic performance of these samples.It demonstrates that Pt-Fe_2O_3 nanospheres can catalyze 100 % conversion of CO into CO_2 at 90°C, indicating superior activity relative to Pd-Fe_2O_3 and Au-Fe_2O_3.展开更多
Flexible transparent electrodes(FTEs)made of silver nanowires(AgNWs)have been widely used in wearable and foldable electronics devices.For obtaining FTEs with both high transparency and low resistance,the AgNWs networ...Flexible transparent electrodes(FTEs)made of silver nanowires(AgNWs)have been widely used in wearable and foldable electronics devices.For obtaining FTEs with both high transparency and low resistance,the AgNWs network should be highly cross-aligned with a low density.Various solution processes have been developed,but most suffer from poor control of the distribution of the AgNWs.展开更多
Synthetic materials with tunable mechanical properties have great potential in soft robotics and biomedical engineering.However,current materials are limited to the mechanical duality altering their mechanical propert...Synthetic materials with tunable mechanical properties have great potential in soft robotics and biomedical engineering.However,current materials are limited to the mechanical duality altering their mechanical properties only between soft and hard states and lack of consecutively programmable mechanics.Herein,the magnetic-programmable organohydrogels with heterogeneous dynamic architecture are designed by encasing oleophilic ferrofluid droplets into hydrogel matrix.As magnetic field increases,the mechanical properties of organohydrogels can be consecutively modulated owing to the gradual formation of chain-like assembly structures of nanoparticles.The storage modulus G'increases by 2.5 times when magnetic field goes up to 0.35 T.Small-Angle X-ray Scattering(SAXS)confirms the reconfigurable orientation of nanoparticles and the organohydrogels show reversible modulus switching.Besides,the materials also exhibit high stretchability,magnetic actuation behavior and effective self-healing capability.Furthermore,the organohydrogels are applied into the design of effectors with mechanical adaptivity.When subjected to serious external perturbations,the effector can maintain mechanical homeostasis by regulating modulus of organohydrogel under applied magnetic field.Such materials are applicable to homeostatic systems with mechanically adaptive behaviors and programmed responses to external force stimuli.展开更多
Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however t...Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.展开更多
One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.H...One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.However,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great challenge.Here we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel surfaces.The nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based materials.Electrical conductivity of our nanocomposite films reaches the maximum of about 1100 S/m.The fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.展开更多
Entanglement-breaking(EB)subspaces determine the additivity of entanglement of formation(EOF),which is a long-standing issue in quantum information.We explicitly construct the twodimensional EB subspaces of any bipart...Entanglement-breaking(EB)subspaces determine the additivity of entanglement of formation(EOF),which is a long-standing issue in quantum information.We explicitly construct the twodimensional EB subspaces of any bipartite system,when system dimensions are equal,and we apply the subspaces to construct EB spaces of arbitrary dimensions.We also present partial construction when system dimensions are different.Then,we present the notion and properties of EB subspaces for some systems,and in particular the absolute EB subspaces.We construct some examples of absolute EB subspaces,as well as EB subspaces for some systems by using multiqubit Dicke states.展开更多
Quantifying entanglement measures for quantum states with unknown density matrices is a challenging task.Machine learning offers a new perspective to address this problem.By training machine learning models using expe...Quantifying entanglement measures for quantum states with unknown density matrices is a challenging task.Machine learning offers a new perspective to address this problem.By training machine learning models using experimentally measurable data,we can predict the target entanglement measures.In this study,we compare various machine learning models and find that the linear regression and stack models perform better than others.We investigate the model's impact on quantum states across different dimensions and find that higher-dimensional quantum states yield better results.Additionally,we investigate which measurable data has better predictive power for target entanglement measures.Using correlation analysis and principal component analysis,we demonstrate that quantum moments exhibit a stronger correlation with coherent information among these data features.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52275471,52120105008)New Cornerstone Science Foundation through the Xplorer Prize。
文摘In recent years,the rapid development of large-scale satellite constellations has challenged the mass production capabilities of satellite manufacturers.Assembly is the last and critical phase of satellite production.Achieving satellite mass assembly is the key to realizing satellite mass production.To this end,satellite manufacturers are working to construct the satellite mass assembly shop-floor(SMAS)to enable moving assembly.However,there is still a lack of a modularized manufacturing system oriented to flexible production for SMAS,as well as disturbance detection methods and production-logistics synchronization methods to deal with various disturbances.Therefore,this paper proposes a digital twin-based production-logistics synchronization system(DT-PLSS)for SMAS.The framework of DT-PLSS is introduced first.In this framework,DT-PLSS can achieve modular construction,as well as distributed management and control.Based on the proposed framework,the construction methods of resource level digital twin(DT),workstation level DT,and shop-floor level DT in SMAS are discussed.The DT-based disturbance detection method for SMAS is presented,aiming to detect or predict di erent types of disturbances and to analyze the e ect of disturbances.Then,a DT enhanced production-logistics synchronization mechanism for SMAS is proposed.With this mechanism,the logistics distribution in the dynamic shop-floor environment and production-logistics synchronization under various disturbances can be realized.Finally,a case study in a real SMAS verifies the feasibility and e ectiveness of the proposed system and methods.This research proposes a practical framework and system which could realize disturbance detection,logistics distribution,and the production-logistics synchronization in complex SMAS scenario e ectively.
基金Supported by National Natural Science Foundation of China(NSFC)(Grant Nos.52120105008,52005026,52005025).
文摘In recent years,as a promising way to realize digital transformation,digital twin shop-floor(DTS)plays an impor-tant role in smart manufacturing.The core feature of DTS is the synchronization.How to implement and maintain the synchronization is critical for DTS.However,there is still a lack of a common definition for synchronization in DTS.Besides,a systematic synchronization mechanism for DTS is strongly needed.This paper first summarizes the defi-nition and requirements of synchronization in DTS,to clarify the understanding of synchronization in DTS.Then,a 5M synchronization mechanism for DTS is proposed,where 5M refers to multi-system data,multi-fidelity model,multi-resource state,multi-level state,and multi-stage operation.As a bottom-up synchronization mechanism,5M synchronization mechanism for DTS has the potential to support DTS to achieve and maintain physical-virtual state synchronization,and to realize operation synchronization of DTS.The implementation methods of 5M synchronization mechanism for DTS are also introduced.Finally,the proposed synchronization mechanism is validated in a digital twin satellite assembly shop-floor,which proves the effectiveness and feasibility of the mechanism.
基金supported by the National Natural Science Foundation of China(Grant Numbers 51375261,51520105007,51405258,51605019)support from the Beihang University,China,through Zhuoyue program
文摘The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell on the surface of the Ag nanowires and cause atomic contact to promote the diffusion and nanojoining at the Ag and Au interface. Severe slip bands were observed in the Ag nanowires after the deformation. A metallic bond was formed at the interface, with the Ag diffusing into the Au more than the Au diffused into the Ag. This nanoscale wire bonding might present opportunities for nanoscale packaging and nanodevice design.
基金financially supported in part by the National Key Research and Development Program of China under Grant 2020YFB1708400the National Natural Science Foundation of China(NSFC)under Grant 52120105008 and Grants 52005026。
文摘Digital twin is currently undergoing a significant transformation from the conceptual and theoretical research phase to the implementation and application phase.However,a universally adaptable research and development platform for digital twin is critically needed to meet the development requirements.Specifically,a publicly accessible simulation,testing,and validation platform which can support digital twin model building,data processing,algorithm design,configuration,etc.,is urgently required for researchers.Furthermore,for developers from the industry,a lowcode development platform that can offer a customizable suite of functions such as model creation,data management,protocol configuration,and visualization is urgently needed.Meanwhile,for enterprise users,there is a lack of an application management platform that can be configured and migrated for various application scenarios,functions,and modes.Therefore,based on the system research of digital twin theories and key technologies by the authors(such as the five-dimension digital twin model,digital twin modeling and digital twin data theory,digital twin standards,and so on),a digital twin software platform reference architecture,namely make Twin,is proposed and designed,as well as its ten core functions.The workflow of the make Twin and the interaction mechanisms among its core functions are described.Finally,a digital twin application system for a chemical fiber textile shop floor(CFTS)which was developed according to make Twin,is introduced,which validates the proposed reference architecture.
基金supported by the National Key Research and Development Program of China(2022YFB3807200)
文摘Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are key catalytic processes in various renewable energy conversion and energy storage technologies.Herein,we systematically investigated the ORR and OER catalytic activity of the single-atom catalysts(SACs)composed of 4d/5d period transition metal(TM)atoms embedded on MBene substrates(TM-M_(2)B_(2)O_(2),M=Ti,Mo,and W).We found that TM dominates the catalytic activity compared to the MBene substrates.The SACs embedded with Rh,Pd,Au,and Ir exhibit excellent ORR or OER catalytic activity.Specifically,Rh-Mo2B2O2and Rh-W2B2O2are promising bifunctional catalysts with ultra-low ORR/OER overpotentials of 0.39/0.21 V and0.19/0.32 V,respectively,lower than that of Pt/RuO_(2)(0.45/0.42 V).Importantly,through machine learning,the models containing 10 element features of SACs were developed to quickly and accurately identify the superior ORR and OER electrocatalysts.Our findings provide several promising SACs for ORR and OER,and offer effective models for catalyst design.
基金Project supported by the National Natural Science Foundation of China(Grant No.11904015)the Fundamental Research Funds for the Central Universities(Grant No.YWF-22-K-101)the National Key R&D Program of China(Grant No.2018YFE0202700)。
文摘The planar Hall effect(PHE),which originates from anisotropic magnetoresistance,presents a qualitative and simple approach to characterize electronic structures of quantum materials by applying an in-plane rotating magnetic field to induce identical oscillations in both longitudinal and transverse resistances.In this review,we focus on the recent research on the PHE in various quantum materials,including ferromagnetic materials,topological insulators,Weyl semimetals,and orbital anisotropic matters.Firstly,we briefly introduce the family of Hall effect and give a basic deduction of PHE formula with the second-order resistance tensor,showing the mechanism of the characteristicπ-period oscillation in trigonometric function form with aπ/4 phase delay between the longitudinal and transverse resistances.Then,we will introduce the four main mechanisms to realize PHE in quantum materials.After that,the origin of the anomalous planar Hall effect(APHE)results,of which the curve shapes deviate from that of PHE,will be reviewed and discussed.Finally,the challenges and prospects for this field of study are discussed.
基金The authors would like to acknowledge support from the National Natural Science Foundation of China(51875313 and 51705013)the Open Foundation of the State Key Laboratory of Tribology&Institute of Manufacturing Engineering(SKLT2019C09).
文摘This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.
基金Supported by the National Natural Science Foundation of China (Grant No.51672015)the National Key Research and Development Program of China (Grant Nos.2016YFC1102500 and 2017YFB0702100)+3 种基金the 111 Project (Grant No.B17002)and the Fundamental Research Funds for the Central Universitiessupported by the European Regional Development Fund in the IT4Innovations National Supercomputing Center—Path to Exascale Project (Grant No.CZ.02.1.01/0.0/0.0/16 013/0001791)within the Operational Programme for Research,Development and Education,and by the Large Infrastructures for Research,Experimental Development,and Innovation Project (Grant No.e-INFRA CZ-LM2018140) by the Ministry of Education,Youth,Sport of the Czech Republic。
文摘Diamond, cubic boron nitride(c-BN), silicon(Si), and germanium(Ge), as examples of typical strong covalent materials, have been extensively investigated in recent decades, owing to their fundamental importance in material science and industry. However, an in-depth analysis of the character of these materials' mechanical behaviors under harsh service environments, such as high pressure, has yet to be conducted. Based on several mechanical criteria, the effect of pressure on the mechanical properties of these materials is comprehensively investigated.It is demonstrated that, with respect to their intrinsic brittleness/ductile nature, all these materials exhibit ubiquitous pressure-enhanced ductility. By analyzing the strength variation under uniform deformation, together with the corresponding electronic structures, we reveal for the first time that the pressure-induced mechanical softening/weakening exhibits distinct characteristics between diamond and c-BN, owing to the differences in their abnormal charge-depletion evolution under applied strain, whereas a monotonous weakening phenomenon is observed in Si and Ge. Further investigation into dislocation-mediated plastic resistance indicates that the pressure-induced shuffle-set plane softening in diamond(c-BN), and weakening in Si(Ge), can be attributed to the reduction of antibonding states below the Fermi level, and an enhanced metallization, corresponding to the weakening of the bonds around the slipped plane with increasing pressure, respectively. These findings not only reveal the physical mechanism of pressure-induced softening/weakening in covalent materials, but also highlights the necessity of exploring strain-tunable electronic structures to emphasize the mechanical response in such covalent materials.
基金sponsored by the National Natural Science Foundation of China(Grant Nos.52275471 and 52175448)Beijing Nova Program No.20220484015the New Cornerstone Science Foundation through the XPLORERPRIZE.
文摘Maintenance of aero-engine fleets is crucial for the efficiency,safety,and reliability of the aviation industry.With the increasing demand for air transportation,maintaining high-performing aero-engines has become significant.Collaborative maintenance,specifically targeting aero-engine fleets,involves the coordination of multiple tasks and resources to enhance management efficiency and reduce costs.Digital Twin(DT)technology provides essential technical support for the intelligent operation and maintenance of aero-engine fleets.DT maps physical object properties to the virtual world,creating high-fidelity,dynamic models.However,DT-enhanced collaborative maintenance faces various challenges,including the construction of complex system-layer DT models,management of massive integrated DT data,and the development of fusion mechanisms and decision-making methods for DT data and models.Overcoming these challenges will allow the aviation industry to optimize aero-engine fleet maintenance,ensuring safety,efficiency,and cost-effectiveness while meeting the growing demand for air transportation.
文摘Cavefish, with sensitive lateral lines, can swim freely and locate preys in invisible and complex cave environments, though their eyes are greatly degenerated. Investigations on the morphology and distribution characteristics of their lateral line systems would benefit our understanding of the high-sensitivity mechanism of the fish. In this study, the arrangement and morphology of the lateral lines are described for two species ofSinocyclocheilus： S. macrophthalmus and S. microphthalmus, which live in the karst caves in Guangxi, China. The behavior experiments indicate that the lateral line system of the S. macrophthalmus is more sensitive at a low vibration frequency range from 20 Hz to 70 Hz. The cephalic and trunk lateral line systems both contribute to the efficient object-locating capability. For both of the two species of cavefish, the diameter of the lateral canal nearby the neuromasts is narrower than that nearby the canal pores. This variation can increase the normal pressure to the surface of the cupula, and increase the sensitivity of the canal lateral line system.
基金financially supported by the National Natural Science Foundation of China (21574004)the National Natural Science Funds for Distinguished Young Scholar (21725401)+2 种基金the Fundamental Research Funds for the Central Universitiesthe National ‘Young Thousand Talents Program’the China Postdoctoral Science Foundation (2017M620012)
文摘Stimuli-responsive hydrogels have become one of the most popular artificial soft materials due to their excellent adaption to complex environments. Thermoresponsive hydrogels triggered by temperature change can be efficiently utilized in many applications. However, these thermoresponsive hydrogels mostly cannot recover their mechanical states under large strain during the process. Herein, we utilize the heterogeneous comb-type polymer network with semicrystalline hydrophobic side chains to design self-recovery semi-crystalline hydrogels. Based on hydrophilic/hydrophobic cooperative complementary interaction and heterogeneous polymer network, hydrogels can be endowed with excellent thermosensitive properties and mechanical performance. The hydrogels exhibit high compressive strength(7.57 MPa) and compressive modulus(1.76 MPa) due to the semi-crystalline domains formed by association of the hydrophobic poly(ε-caprolactone) PCL. The melting-crystalline transition of PCL and elastic polymer network provide the hydrogels excellent thermomechanical performance and self-recovery property. Furthermore, the hydrogels exhibit shape memory behavior, which can be realized by simple process and smart surface patterning. With these excellent properties, our hydrogels can be applied in sensors, flexible devices and scaffolds for tissue engineering.
基金This work is supported by the National Natural Science Foundation of China(51872017)the high-performance computing(HPC)resources at Beihang University。
文摘Layered IV-V-VI semiconductors have immense potential for thermoelectric(TE)applications due to their intrinsically ultralow lattice thermal conductivity.However,it is extremely difficult to assess their TE performance via experimental trial-and-error methods.Here,we present a machine-learning-based approach to accelerate the discovery of promising thermoelectric candidates in this chalcogenide family.Based on a dataset generated from high-throughput ab initio calculations,we develop two highly accurateand-efficient neural network models to predict the maximum ZT(ZT_(max))and corresponding doping type,respectively.The top candidate,n-type Pb_(2)Sb_(2)S_(5),is successfully identified,with the ZT_(max) over 1.0 at 650 K,owing to its ultralow thermal conductivity and decent power factor.Besides,we find that n-type Te-based compounds exhibit a combination of high Seebeck coefficient and electrical conductivity,thereby leading to better TE performance under electron doping than hole doping.Whereas p-type TE performance of Se-based semiconductors is superior to n-type,resulting from large Seebeck coefficient induced by high density-ofstates near valence band edges.
基金supported by the National Natural Science Foundation(21574004 and 21421061)National Research Fund for Fundamental Key Projects(2013CB933000,2012CB933800,2012CB934100,and 2014CB932203)+1 种基金the Key Research Program of the Chinese Academy of Sciences(KJZD-EW-M01,and KJZD-EW-M03)the 111 project(B14009)
文摘Binary cooperative complementary materials,consisting of two components with entirely opposite physiochemical properties at the nanoscale, are presented as a novel principle for the design and construct of functional materials. By summarizing recent achievement in materials science, it can be found that the cooperative interaction distance between the pair of complementary property must be comparable with the scale of related physical or chemical parameter. When the binary components are in the cooperative distance, the cooperation between these building blocks becomes dominant and endows the macroscopic materials with unique properties and advanced functionalities that cannot be achieved by either of building blocks.
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China(51272249,51372007 and 21301014)the China Postdoctoral Science Foundation funded project
文摘A facile in situ redox strategy has been developed to fabricate surfactant-free M-Fe_2O_3(M = Pt, Pd, Au) hybrid nanospheres. In this process, noble metal salts were directly reduced by the pre-prepared Fe_3O_4 components in an alkaline aqueous solution without using organic reductants and surfactants. During the redox reaction, Fe_3O_4 was oxidized into Fe_2O_3,and the reduzates of noble metal nanoparticles were deposited on the surface of the Fe_2O_3 nanospheres. Then the characterizations were discussed in detail to study the formation of M-Fe_2O_3 hybrids. At last, catalytic CO oxidation was selected as a model reaction to evaluate the catalytic performance of these samples.It demonstrates that Pt-Fe_2O_3 nanospheres can catalyze 100 % conversion of CO into CO_2 at 90°C, indicating superior activity relative to Pd-Fe_2O_3 and Au-Fe_2O_3.
基金supported by the National Key R&D Program of China(no.2018YFA0704801)the National Natural Science Foundation of China(no.21872002).
文摘Flexible transparent electrodes(FTEs)made of silver nanowires(AgNWs)have been widely used in wearable and foldable electronics devices.For obtaining FTEs with both high transparency and low resistance,the AgNWs network should be highly cross-aligned with a low density.Various solution processes have been developed,but most suffer from poor control of the distribution of the AgNWs.
基金the National Natural Science Funds for Distinguished Young Scholar(No.21725401)the National Key R&D Program of China(No.2017YFA0207800)+1 种基金the 111 project(No.B14009)the Fundamental Research Funds for the Central Universities.
文摘Synthetic materials with tunable mechanical properties have great potential in soft robotics and biomedical engineering.However,current materials are limited to the mechanical duality altering their mechanical properties only between soft and hard states and lack of consecutively programmable mechanics.Herein,the magnetic-programmable organohydrogels with heterogeneous dynamic architecture are designed by encasing oleophilic ferrofluid droplets into hydrogel matrix.As magnetic field increases,the mechanical properties of organohydrogels can be consecutively modulated owing to the gradual formation of chain-like assembly structures of nanoparticles.The storage modulus G'increases by 2.5 times when magnetic field goes up to 0.35 T.Small-Angle X-ray Scattering(SAXS)confirms the reconfigurable orientation of nanoparticles and the organohydrogels show reversible modulus switching.Besides,the materials also exhibit high stretchability,magnetic actuation behavior and effective self-healing capability.Furthermore,the organohydrogels are applied into the design of effectors with mechanical adaptivity.When subjected to serious external perturbations,the effector can maintain mechanical homeostasis by regulating modulus of organohydrogel under applied magnetic field.Such materials are applicable to homeostatic systems with mechanically adaptive behaviors and programmed responses to external force stimuli.
基金supported by the National Key Research and Development Project(No.2022YFA1503000)the National Natural Science Foundation of China(Nos.22161142021 and 22175010).
文摘Polymer composite fibers with superior properties such as excellent combined strength and toughness and biocompatibility can be used in high-tech applications of braided protective devices and smart wearable,however the research of high-performance polymer composite fiber remains in the infant stage.Here we present a strategy to produce strong and tough anisotropic polymer nanocomposite fibers with orientedly aligned salt rods using mechanical stretching-assisted salting-out treatment.The prepared nanocomposite fibers have a tensile strength of up to 786±2.7 MPa and an elongation at break of 81%,and the anisotropic fibers exhibit good transmission of mechanical vibration in the longitudinal direction with high resolution.During the fabrication process,the salt builds up into oriented rods during the directional salting process,and the polymer is confined to the 150 nm domain between the rods after the solvent is completely evaporated,giving the nanocomposite fibers superior mechanical properties.The presented strategy can be applied to the continuous mass production of nanocomposite fibers and is also generalizable to other polymer nanocomposites,which could extend the applicability of nanocomposite fibers to conditions involving more demanding mechanical loading and mechanical vibration transmission.
基金supported by the National Key Research and Development Program of China(No.2022YFA1503000)the National Natural Science Foundation of China(Nos.22161142021 and 22175010).
文摘One-dimensional(1D)aramid nanofiber(ANF)based nanocomposite films have drawn increasing attentions in various applications due to their excellent mechanical properties and impressive chemical and thermal stabilities.However,the large-area fabrication of aramid nanocomposite films with ultrastrong mechanical properties under mild conditions remains a great challenge.Here we present a facile superspreading-assisted strategy to produce aramid nanofiber based oriented layered nanocomposites using phase inversion process that occurs at the fully swollen hydrogel surfaces.The nanocomposite films based on ANF,carboxylation carbon tube(CNT–COOH),poly(vinyl alcohol)(PVA),and MXene nanosheet exhibit a tensile strength of up to 870.8±85 MPa,a Young’s modulus of 21.8±2.2 GPa,and outstanding toughness(up to 43.2±4.6 MJ/m^(3)),which are much better than those conventional aramid nanofiber based materials.Electrical conductivity of our nanocomposite films reaches the maximum of about 1100 S/m.The fabulous mechanical properties combination and continuous production capability render our strategy representing a promising direction for the development of high-performance nanocomposites.
文摘Entanglement-breaking(EB)subspaces determine the additivity of entanglement of formation(EOF),which is a long-standing issue in quantum information.We explicitly construct the twodimensional EB subspaces of any bipartite system,when system dimensions are equal,and we apply the subspaces to construct EB spaces of arbitrary dimensions.We also present partial construction when system dimensions are different.Then,we present the notion and properties of EB subspaces for some systems,and in particular the absolute EB subspaces.We construct some examples of absolute EB subspaces,as well as EB subspaces for some systems by using multiqubit Dicke states.
基金supported by the NNSF of China(Grant No.11871089).
文摘Quantifying entanglement measures for quantum states with unknown density matrices is a challenging task.Machine learning offers a new perspective to address this problem.By training machine learning models using experimentally measurable data,we can predict the target entanglement measures.In this study,we compare various machine learning models and find that the linear regression and stack models perform better than others.We investigate the model's impact on quantum states across different dimensions and find that higher-dimensional quantum states yield better results.Additionally,we investigate which measurable data has better predictive power for target entanglement measures.Using correlation analysis and principal component analysis,we demonstrate that quantum moments exhibit a stronger correlation with coherent information among these data features.
