Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in ph...Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in physiotherapy and rehabilitation represents a paradigm shift from traditional therapeutic approaches to personalized data-driven interventions that optimize patient outcomes.This narrative review examines the current applications,benefits,challenges,and future prospects of digital twin technology in physiotherapy and rehabilitation,providing a comprehensive analysis of the manner in which this technology is reshaping clinical practice and patient care.A narrative review approach was employed,systematically searching PubMed,IEEE Xplore,Scopus,and Web of Science databases.Studies describing digital twin applications,development methodologies,clinical implementations,and theoretical frameworks in physiotherapy and rehabilitation contexts were included.Digital twin technology demonstrates significant potential in personalizing rehabilitation programs,enabling real-time monitoring of patient progress,predicting treatment outcomes,and facilitating remote therapeutic interventions.Current applications span musculoskeletal rehabilitation,neurological recovery,post surgical care,and sports injury management.Key benefits include enhanced treatment precision,improved patient engagement,reduced healthcare costs,and accelerated recovery times.However,implementation faces challenges including technological complexity,data privacy concerns,interoperability issues,and the need for substantial infrastructure investment.Digital twin technology represents a promising frontier in physiotherapy and rehabilitation,offering unprecedented opportunities for personalized,efficient,and effective patient care.Successful integration requires addressing the current limitations while fostering interdisciplinary collaboration between clinicians,engineers,and data scientists.展开更多
The integration of digital twin(DT)technology with microseismic(MS)monitoring for evaluating the dynamic response of high-arch dams remains under-explored.This paper investigates the application of MS monitoring on th...The integration of digital twin(DT)technology with microseismic(MS)monitoring for evaluating the dynamic response of high-arch dams remains under-explored.This paper investigates the application of MS monitoring on the Dagangshan high-arch dam during its normal water storage operating period to assess potential damage.The study analyzes the MS characteristics of the dam during the Luding earthquake(Ms=6.8).A framework for constructing a damage driven DT model of a high-arch dam is proposed.The DT model is capable of self-updating its mechanical parameters based on MS data.Seismic response calculations are conducted utilizing cloud computing,allowing for the direct presentation of results within the DT model.The results indicate a high-risk area of the Dagangshan arch dam,characterized by significantMS deformation,primarily centered on the arch crown beam.This zone encompasses dam sections Nos.5-6,10-11,13-16,and 19-20,all located above 1030 m elevation.Under seismic loading,the arch dam exhibits a back-and-forth movement along the river,ultimately reaching a stable state.Following the earthquake,the stress state of the dam does not experience substantial changes.The average relative error between numerical results and measured peak ground acceleration values is 17%when considering the cumulative effect of damage,compared to 36%when neglecting this effect.This study presents a more reliable approach for assessing the state of dams.展开更多
As unmanned underwater vehicles (UUVs) are increasingly designed to perform long-duration missions in highly complex and often extreme environments, traditional design methods face significant and growing challenges^(...As unmanned underwater vehicles (UUVs) are increasingly designed to perform long-duration missions in highly complex and often extreme environments, traditional design methods face significant and growing challenges^([1,2]).展开更多
The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often...The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.展开更多
1.Introduction.Twinning is a fundamental mechanism for plastic deformation in many face-centered cubic(FCC)metals having low stacking fault energies(SFEs)[1,2].In particular,twinning-induced plasticity(TWIP)alloys hav...1.Introduction.Twinning is a fundamental mechanism for plastic deformation in many face-centered cubic(FCC)metals having low stacking fault energies(SFEs)[1,2].In particular,twinning-induced plasticity(TWIP)alloys have excellent tensile properties as a result of the intensive twinning activity[3-5].The twin boundaries also have been proven to contribute to an improved strengthening-toughening effect,mechanical stability and even fatigue performance,relative to high-angle grain boundaries and low-angle grain boundaries[6-11].Therefore,it is of major interest to clarify the twinning mechanism and thereby improve the mechanical properties of metallic materials.展开更多
Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin facets.This occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to cre...Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin facets.This occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to create twin facets.A comprehensive under-standing of twin facets associated with 3D twins,including their atomic structures and energies,is crucial for understanding deformation twinning.In this study,we propose a molecular statics/dynamics(MS/MD)approach to determine characteristic twin facets enclosing 3D non-equilibrium/equilibrium{1011}twin domains,which has been much less studied than the counterpart{1012}twin domains.The stability of different TD pile-up arrangement with varying line senses informs the morphology of 3D non-equilibrium twins,which are bounded by{1010}_(T)||{1013}_(M),{1011}_(T)||{0002}_(M)and{1013}_(T)||{1013}_(M)coherent facets associated with pile-up of edge TDs,and discrete non-edge TDs aligned along CTBs with their line senses parallel to<4513>,<1101>,<5416><2113>or<1012>axes.Formation of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations.3D equilibrium{1011}twins may comprise{1011}_(T)||{0002}_(M),{1457}_(T)||{3419}_(M),{1657}_(T)||{5617}_(M),{1433}_(T)||{3413}_(M),{0110}_(T)||{0111}_(M)and{0221}_(T)||{0221}_(M)semi-coherent facets in<1210>,<4513>,<1101>,<5416>,<2113>and<1012>axes,respectively.展开更多
A statistical analysis of the twinning behavior in a basal-textured Mg sheet under hard orientation loading was performed at strain rates of 1×10^(-5) and 1×10^(-1) s^(-1) with grain sizes of 70 and 20µ...A statistical analysis of the twinning behavior in a basal-textured Mg sheet under hard orientation loading was performed at strain rates of 1×10^(-5) and 1×10^(-1) s^(-1) with grain sizes of 70 and 20µm.There were 1609 tension twins identified including adequate(51%)anomalous twins(Schmid factor m<0).Twin variant selection exhibited almost no grain size or strain rate effects.Most twin variants(74%)correlated well with the proposed normalized Schmid factor(mnor).The Luster-Morris parameter(m′)values failed to correlate with the twin transmission,while 96%of transmitted pairs exhibited large mnor or normalized m′(m′nor)values.Twin transmission occurred more frequently at lower grain boundary misorientation angles(10°-30°).The active anomalous twins correlated well with m of the prismatic slip.The present work provided a statistical perspective that,the mnor and m′nor can correlate the anomalous twinning rather than m and m′.The local condition also played a critical role in anomalous twinning behavior.展开更多
BACKGROUND The incidence of multiple pregnancies has increased worldwide recently and women with a twin pregnancy are at higher risk of adverse outcomes compared with women with a singleton pregnancy.It is important t...BACKGROUND The incidence of multiple pregnancies has increased worldwide recently and women with a twin pregnancy are at higher risk of adverse outcomes compared with women with a singleton pregnancy.It is important to understand the risk factors for adverse fetal outcomes in twin pregnancy in order to guide clinical management.AIM To identify the independent risk factors,including maternal personal and family medical histories and first trimester ultrasound screening findings,for adverse fetal outcomes of twin pregnancy before 28 weeks of gestation.METHODS The data of 126 twin pregnancies in our hospital,including pregnancy outcomes,first trimester ultrasound screening findings and maternal medical history,were retrospectively collected.Twenty-nine women with adverse outcomes were included in the abnormal group and the remaining 97 women were included in the control group.RESULTS Patients in the abnormal group were more likely to be monochorionic diamniotic(13/29 vs 20/97,P=0.009),with a higher mean pulsatility index(PI,1.57±0.55 vs 1.28±0.42,P=0.003;cutoff value:1.393)or a higher mean resistance index(0.71±0.11 vs 0.65±0.11,P=0.008;cutoff value:0.683)or early diastolic notch of bilateral uterine arteries(UtAs,10/29 vs 15/97,P=0.024)or with abnormal ultrasound findings(13/29 vs 2/97,P<0.001),compared with the control group.Monochorionic diamnioticity,higher mean PI of bilateral UtAs and abnormal ultrasound findings during first trimester screening were independent risk factors for adverse fetal outcomes(P<0.05).CONCLUSION First trimester ultrasound screening for twin pregnancy identifies independent risk factors and is useful for the prediction of fetal outcomes.展开更多
Digital twin is considered the key technique for real-time monitoring and life-cycle management of electric equipment.To construct the digital twin model of electric equipment,a multi-parameter electromagnetic analysi...Digital twin is considered the key technique for real-time monitoring and life-cycle management of electric equipment.To construct the digital twin model of electric equipment,a multi-parameter electromagnetic analysis is needed to generate a large amount of high fidelity data under various working condition.However,repeated solving such multi-parameter electromagnetic problems based on full order finite element method may lead to extreme scale calculations.To address this issue,a hybrid approach that combines tensor decomposition and proper orthogonal decomposition(POD)is introduced,which can effectively establish a reduced order model for multi-parameter electromagnetic field problems.The performance of the proposed approach is illustrated through three numerical examples,namely an electrical motor,a transformer and a voice coil actuator including parameter variations of operating conditions,geometric parameters,and material parameters.The numerical results show that the proposed hybrid approach has significant advantage compared to conventional reduced order model in situation where the solution changes dramatically within the parameter variation range and even more apparent when the parameter dimension is high.展开更多
This study proposes an automatic control system for Autonomous Underwater Vehicle(AUV)docking,utilizing a digital twin(DT)environment based on the HoloOcean platform,which integrates six-degree-of-freedom(6-DOF)motion...This study proposes an automatic control system for Autonomous Underwater Vehicle(AUV)docking,utilizing a digital twin(DT)environment based on the HoloOcean platform,which integrates six-degree-of-freedom(6-DOF)motion equations and hydrodynamic coefficients to create a realistic simulation.Although conventional model-based and visual servoing approaches often struggle in dynamic underwater environments due to limited adaptability and extensive parameter tuning requirements,deep reinforcement learning(DRL)offers a promising alternative.In the positioning stage,the Twin Delayed Deep Deterministic Policy Gradient(TD3)algorithm is employed for synchronized depth and heading control,which offers stable training,reduced overestimation bias,and superior handling of continuous control compared to other DRL methods.During the searching stage,zig-zag heading motion combined with a state-of-the-art object detection algorithm facilitates docking station localization.For the docking stage,this study proposes an innovative Image-based DDPG(I-DDPG),enhanced and trained in a Unity-MATLAB simulation environment,to achieve visual target tracking.Furthermore,integrating a DT environment enables efficient and safe policy training,reduces dependence on costly real-world tests,and improves sim-to-real transfer performance.Both simulation and real-world experiments were conducted,demonstrating the effectiveness of the system in improving AUV control strategies and supporting the transition from simulation to real-world operations in underwater environments.The results highlight the scalability and robustness of the proposed system,as evidenced by the TD3 controller achieving 25%less oscillation than the adaptive fuzzy controller when reaching the target depth,thereby demonstrating superior stability,accuracy,and potential for broader and more complex autonomous underwater tasks.展开更多
In this work,a new strategy is proposed to improve the pseudoelasticity stability of NiTi SMAs under strains beyond the martensite transformation stress plateau by introducing homogeneous Ni_(4) Ti_(3) pre-cipitates,m...In this work,a new strategy is proposed to improve the pseudoelasticity stability of NiTi SMAs under strains beyond the martensite transformation stress plateau by introducing homogeneous Ni_(4) Ti_(3) pre-cipitates,multiple martensite variants,and high-density austenite twins.Our experimental results show that this new strategy achieves excellent and stable pseudoelasticity with a recoverable ratio up to 85.5%larger than the highest value ever reported of 63.4%after 40 cyclic loading under a fixed strain of 14%due to the introduction of high-density austenite twins.The mechanisms of this promising property are revealed with the aid of subregional(grain boundary and grain interior)EDS,TEM,and in-situ BSE anal-ysis.First,an appropriate forging and aging process introduces homogenous Ni_(4) Ti_(3) precipitates,which reduce the energy dissipation required for one pseudoelastic loop from 4.49 to 2.48 J g^(-1) by changing the phase transformation path and temperature.Second,the high-density austenite twins induced by de-formed martensite twins during cyclic loading enhance the strength of the matrix.The reduced energy dissipation and stronger matrix improve the pseudoelasticity and its stability.We attribute these bene-ficial microstructure features to the specially designed processing routes:forging and subsequent aging.On the one hand,the dislocations induced by forging provide homogeneous nucleation sites,leading to Ni_(4) Ti_(3) homogeneously precipitating during aging;on the other hand,the dense and homogeneously dis-tributed precipitates accelerate the martensite transformation and increase the elastic modulus of the martensite,resulting in the advancement of the second stress plateau from 38%to 12%,in which part of the martensite is reoriented to generate multiple martensite variants,resulting in the formation of de-formation{113}_(B19′)martensite twin.It transforms into(112)[111]_(B2) austenite twin after unloading.These findings pave a feasible avenue for tailoring the functional properties of SMAs.展开更多
A strong basal texture is typically developed in magnesium alloy sheets that have been subjected to the rolling process.Consequently,their mechanical properties and formability are significantly impaired,which in turn...A strong basal texture is typically developed in magnesium alloy sheets that have been subjected to the rolling process.Consequently,their mechanical properties and formability are significantly impaired,which in turn restricts potential applications.In this study,an innovative texture-altering technique,which involves in-plane free compression and width-constrained rolling(FCWR),is used for AZ31 alloy sheets in order to manufacture magnesium alloy sheets with both high strength and high ductility.During FCWR deformation process,a substantial number of tensile twins and a small quantity of(1012)-(01¯12)twin-twin boundaries are induced to coordinate plastic deformation.It is precisely the presence of such crossed twins that impedes the detwinning of partial twins under low-stress conditions.The retained twins hinder the motion of dislocation,thereby enhancing the strength.Specifically,the yield strength of preset crossed twins sample along rolling direction,45°and transverse direction has increased by 105%,16.8%and 23%,respectively.Additionally,the ultimate tensile strength along these three directions has increased by 42.7%,25.5%and 34.8%,respectively.The twin boundaries in FCWR sample consist of steps,which correspond to basal-prismatic(BP/PB)boundaries that connect straight terraces which are parallel to theoretical{10¯12}twin boundaries.Furthermore,as the number of processing passes increases,the step features become more pronounced.Compared with the as-received sample,the YS enhancement in the sample prepared via the second pass of the FCWR process is attributed to two primary mechanisms:grain refinement strengthening contributes 61 MPa,while dislocation strengthening accounts for 90 MPa.展开更多
Twins play an important role in the texture transition during annealing.In a cold rolled high rare earth content magnesium(Mg)alloys with{10–12}extension twins,{11–21}extension twins,{10–11}compression twins and{10...Twins play an important role in the texture transition during annealing.In a cold rolled high rare earth content magnesium(Mg)alloys with{10–12}extension twins,{11–21}extension twins,{10–11}compression twins and{10–11}-{10–12}double twins and frequent twin-twin interactions,quasi-in-situ electron backscatter diffraction method was used to observe the twin induced static recrystallization(SRX)and related effect on texture during annealing.The results show that basal component was consumed owing to the SRX occurred in basal oriented{10–12}twins and SRXed grains with several specific orientations show preferential grain growth.SRX widely operated in the{10–12}extension and{11–21}extension twins,but absent in most{10–11}compression and{10–11}-{10–12}double twins,which is different to traditional twin induced SRX.Most compression/double twins detwinned while only partial tension twins detwinned.Operation of{11–21}twins and resultant twin-twin interaction facilitate the formation of serrated twin boundaries,which can serve as nucleation sites.Activation of<c+a>dislocation and related dislocation interaction in high dislocation density areas promote the formation of new grain boundaries and related SRX.Profuse<c+a>dislocations in basal oriented twins release the strain accumulation in compression/double twins and thus result in the absence of SRX.The twin size difference,storage energy and dislocation-twin interaction commonly functioned to the detwinning during annealing.The near-coincide site lattice boundaries that show high mobility were considered to be the important contributor to the preferential grain growth of SRXed grains.展开更多
In this work,the{10–12}tensile twins are introduced to improve the drawability of the AZ31 Mg alloy sheet.Concretely,the drawing depth is increased by 32%compared with the as-received sheet at 200℃.This is because{1...In this work,the{10–12}tensile twins are introduced to improve the drawability of the AZ31 Mg alloy sheet.Concretely,the drawing depth is increased by 32%compared with the as-received sheet at 200℃.This is because{10–12}tensile twins promote the occurrences of many deformation mechanisms during warm deep drawing,such as slips,detwinning,dynamic recrystallization(DRX)behaviors,etc.Further,based on the different stress states during deep drawing,these mechanisms and their competition relationships,as well as texture evolutions,are systematically studied.Combined with critical resolved shear stress(CRSS)and microstructure evolution,the global Schmid factor(GSF)obtained by quantizing stress states by stress tensor(σ)can accurately predict the activation trend of deformation mechanisms.It is found that the stress states have a reverse influence on the activation trend of the{10–12}twinning and detwinning.The change of stress states affects the competitive relationships between detwinning and DRX,and then affects the process and degree of DRX.The{10–12}tensile twins and large plane strain promote the activation of prismatic slips,and the larger plane strain also deflected the{10–12}twinning lattice.The{10–12}tensile twins and their induced deformation mechanisms can prominently weaken the basal texture and improve the drawability.展开更多
文摘Digital twin technology,that creates virtual replicas of physical entities using real-time data and simulation models,has emerged as a transformative innovation across multiple healthcare domains.Its application in physiotherapy and rehabilitation represents a paradigm shift from traditional therapeutic approaches to personalized data-driven interventions that optimize patient outcomes.This narrative review examines the current applications,benefits,challenges,and future prospects of digital twin technology in physiotherapy and rehabilitation,providing a comprehensive analysis of the manner in which this technology is reshaping clinical practice and patient care.A narrative review approach was employed,systematically searching PubMed,IEEE Xplore,Scopus,and Web of Science databases.Studies describing digital twin applications,development methodologies,clinical implementations,and theoretical frameworks in physiotherapy and rehabilitation contexts were included.Digital twin technology demonstrates significant potential in personalizing rehabilitation programs,enabling real-time monitoring of patient progress,predicting treatment outcomes,and facilitating remote therapeutic interventions.Current applications span musculoskeletal rehabilitation,neurological recovery,post surgical care,and sports injury management.Key benefits include enhanced treatment precision,improved patient engagement,reduced healthcare costs,and accelerated recovery times.However,implementation faces challenges including technological complexity,data privacy concerns,interoperability issues,and the need for substantial infrastructure investment.Digital twin technology represents a promising frontier in physiotherapy and rehabilitation,offering unprecedented opportunities for personalized,efficient,and effective patient care.Successful integration requires addressing the current limitations while fostering interdisciplinary collaboration between clinicians,engineers,and data scientists.
基金supported by the National Natural Science Foundation of China(Grant Nos.52379098 and 42122052)the Liaoning XingLiao Talent Program(Grant No.XLYC2203008).
文摘The integration of digital twin(DT)technology with microseismic(MS)monitoring for evaluating the dynamic response of high-arch dams remains under-explored.This paper investigates the application of MS monitoring on the Dagangshan high-arch dam during its normal water storage operating period to assess potential damage.The study analyzes the MS characteristics of the dam during the Luding earthquake(Ms=6.8).A framework for constructing a damage driven DT model of a high-arch dam is proposed.The DT model is capable of self-updating its mechanical parameters based on MS data.Seismic response calculations are conducted utilizing cloud computing,allowing for the direct presentation of results within the DT model.The results indicate a high-risk area of the Dagangshan arch dam,characterized by significantMS deformation,primarily centered on the arch crown beam.This zone encompasses dam sections Nos.5-6,10-11,13-16,and 19-20,all located above 1030 m elevation.Under seismic loading,the arch dam exhibits a back-and-forth movement along the river,ultimately reaching a stable state.Following the earthquake,the stress state of the dam does not experience substantial changes.The average relative error between numerical results and measured peak ground acceleration values is 17%when considering the cumulative effect of damage,compared to 36%when neglecting this effect.This study presents a more reliable approach for assessing the state of dams.
基金supported by the National Natural Science Foundation of China (Grant No.52405033)。
文摘As unmanned underwater vehicles (UUVs) are increasingly designed to perform long-duration missions in highly complex and often extreme environments, traditional design methods face significant and growing challenges^([1,2]).
基金The researchers would like to thank the Deanship of Graduate Studies and Scientific Research at Qassim University for financial support(QU-APC-2025)。
文摘The evolution of cities into digitally managed environments requires computational systems that can operate in real time while supporting predictive and adaptive infrastructure management.Earlier approaches have often advanced one dimension—such as Internet of Things(IoT)-based data acquisition,Artificial Intelligence(AI)-driven analytics,or digital twin visualization—without fully integrating these strands into a single operational loop.As a result,many existing solutions encounter bottlenecks in responsiveness,interoperability,and scalability,while also leaving concerns about data privacy unresolved.This research introduces a hybrid AI–IoT–Digital Twin framework that combines continuous sensing,distributed intelligence,and simulation-based decision support.The design incorporates multi-source sensor data,lightweight edge inference through Convolutional Neural Networks(CNN)and Long ShortTerm Memory(LSTM)models,and federated learning enhanced with secure aggregation and differential privacy to maintain confidentiality.A digital twin layer extends these capabilities by simulating city assets such as traffic flows and water networks,generating what-if scenarios,and issuing actionable control signals.Complementary modules,including model compression and synchronization protocols,are embedded to ensure reliability in bandwidth-constrained and heterogeneous urban environments.The framework is validated in two urban domains:traffic management,where it adapts signal cycles based on real-time congestion patterns,and pipeline monitoring,where it anticipates leaks through pressure and vibration data.Experimental results show a 28%reduction in response time,a 35%decrease in maintenance costs,and a marked reduction in false positives relative to conventional baselines.The architecture also demonstrates stability across 50+edge devices under federated training and resilience to uneven node participation.The proposed system provides a scalable and privacy-aware foundation for predictive urban infrastructure management.By closing the loop between sensing,learning,and control,it reduces operator dependence,enhances resource efficiency,and supports transparent governance models for emerging smart cities.
基金supported by the National Natural Science Foundation of China(Nos.52001153,52322105,52271121,52130002 and 52321001)the Youth Innovation Promotion Association CAS(No.202119)+2 种基金the IMR Innovation Fund(No.2023-ZD01)the KC Wong Education Foundation(No.GJTD-2020-09)One of the authors was supported by the European Research Council under grant agreement No.267464-SPDMETALS(TGL).
文摘1.Introduction.Twinning is a fundamental mechanism for plastic deformation in many face-centered cubic(FCC)metals having low stacking fault energies(SFEs)[1,2].In particular,twinning-induced plasticity(TWIP)alloys have excellent tensile properties as a result of the intensive twinning activity[3-5].The twin boundaries also have been proven to contribute to an improved strengthening-toughening effect,mechanical stability and even fatigue performance,relative to high-angle grain boundaries and low-angle grain boundaries[6-11].Therefore,it is of major interest to clarify the twinning mechanism and thereby improve the mechanical properties of metallic materials.
基金supports by the National Key R&D Program of China(No.2022YFB3708900).
文摘Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin facets.This occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to create twin facets.A comprehensive under-standing of twin facets associated with 3D twins,including their atomic structures and energies,is crucial for understanding deformation twinning.In this study,we propose a molecular statics/dynamics(MS/MD)approach to determine characteristic twin facets enclosing 3D non-equilibrium/equilibrium{1011}twin domains,which has been much less studied than the counterpart{1012}twin domains.The stability of different TD pile-up arrangement with varying line senses informs the morphology of 3D non-equilibrium twins,which are bounded by{1010}_(T)||{1013}_(M),{1011}_(T)||{0002}_(M)and{1013}_(T)||{1013}_(M)coherent facets associated with pile-up of edge TDs,and discrete non-edge TDs aligned along CTBs with their line senses parallel to<4513>,<1101>,<5416><2113>or<1012>axes.Formation of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations.3D equilibrium{1011}twins may comprise{1011}_(T)||{0002}_(M),{1457}_(T)||{3419}_(M),{1657}_(T)||{5617}_(M),{1433}_(T)||{3413}_(M),{0110}_(T)||{0111}_(M)and{0221}_(T)||{0221}_(M)semi-coherent facets in<1210>,<4513>,<1101>,<5416>,<2113>and<1012>axes,respectively.
基金supported by the National Natural Science Foundation of China(Nos.52171125,52071178)。
文摘A statistical analysis of the twinning behavior in a basal-textured Mg sheet under hard orientation loading was performed at strain rates of 1×10^(-5) and 1×10^(-1) s^(-1) with grain sizes of 70 and 20µm.There were 1609 tension twins identified including adequate(51%)anomalous twins(Schmid factor m<0).Twin variant selection exhibited almost no grain size or strain rate effects.Most twin variants(74%)correlated well with the proposed normalized Schmid factor(mnor).The Luster-Morris parameter(m′)values failed to correlate with the twin transmission,while 96%of transmitted pairs exhibited large mnor or normalized m′(m′nor)values.Twin transmission occurred more frequently at lower grain boundary misorientation angles(10°-30°).The active anomalous twins correlated well with m of the prismatic slip.The present work provided a statistical perspective that,the mnor and m′nor can correlate the anomalous twinning rather than m and m′.The local condition also played a critical role in anomalous twinning behavior.
基金Supported by Natural Science Foundation of Shanghai,China,No.22ZR1458200Medical Ph.D Innovative Talent Base Project of Changning District,Shanghai,China,No.RCJD2021B09Key Specialty of Changning District,Shanghai,China,No.20231004.
文摘BACKGROUND The incidence of multiple pregnancies has increased worldwide recently and women with a twin pregnancy are at higher risk of adverse outcomes compared with women with a singleton pregnancy.It is important to understand the risk factors for adverse fetal outcomes in twin pregnancy in order to guide clinical management.AIM To identify the independent risk factors,including maternal personal and family medical histories and first trimester ultrasound screening findings,for adverse fetal outcomes of twin pregnancy before 28 weeks of gestation.METHODS The data of 126 twin pregnancies in our hospital,including pregnancy outcomes,first trimester ultrasound screening findings and maternal medical history,were retrospectively collected.Twenty-nine women with adverse outcomes were included in the abnormal group and the remaining 97 women were included in the control group.RESULTS Patients in the abnormal group were more likely to be monochorionic diamniotic(13/29 vs 20/97,P=0.009),with a higher mean pulsatility index(PI,1.57±0.55 vs 1.28±0.42,P=0.003;cutoff value:1.393)or a higher mean resistance index(0.71±0.11 vs 0.65±0.11,P=0.008;cutoff value:0.683)or early diastolic notch of bilateral uterine arteries(UtAs,10/29 vs 15/97,P=0.024)or with abnormal ultrasound findings(13/29 vs 2/97,P<0.001),compared with the control group.Monochorionic diamnioticity,higher mean PI of bilateral UtAs and abnormal ultrasound findings during first trimester screening were independent risk factors for adverse fetal outcomes(P<0.05).CONCLUSION First trimester ultrasound screening for twin pregnancy identifies independent risk factors and is useful for the prediction of fetal outcomes.
基金supported by the UCAS-ULille joint PhD training program and also partially supported within the frame of the EE4.0(Electrical Energy 4.0)project,which is co-financed by the European Union,with the financial support of the European Regional Development Fund(ERDF),the French state,and the French Region of Hautsde-France.
文摘Digital twin is considered the key technique for real-time monitoring and life-cycle management of electric equipment.To construct the digital twin model of electric equipment,a multi-parameter electromagnetic analysis is needed to generate a large amount of high fidelity data under various working condition.However,repeated solving such multi-parameter electromagnetic problems based on full order finite element method may lead to extreme scale calculations.To address this issue,a hybrid approach that combines tensor decomposition and proper orthogonal decomposition(POD)is introduced,which can effectively establish a reduced order model for multi-parameter electromagnetic field problems.The performance of the proposed approach is illustrated through three numerical examples,namely an electrical motor,a transformer and a voice coil actuator including parameter variations of operating conditions,geometric parameters,and material parameters.The numerical results show that the proposed hybrid approach has significant advantage compared to conventional reduced order model in situation where the solution changes dramatically within the parameter variation range and even more apparent when the parameter dimension is high.
基金supported by the National Science and Technology Council,Taiwan[Grant NSTC 111-2628-E-006-005-MY3]supported by the Ocean Affairs Council,Taiwansponsored in part by Higher Education Sprout Project,Ministry of Education to the Headquarters of University Advancement at National Cheng Kung University(NCKU).
文摘This study proposes an automatic control system for Autonomous Underwater Vehicle(AUV)docking,utilizing a digital twin(DT)environment based on the HoloOcean platform,which integrates six-degree-of-freedom(6-DOF)motion equations and hydrodynamic coefficients to create a realistic simulation.Although conventional model-based and visual servoing approaches often struggle in dynamic underwater environments due to limited adaptability and extensive parameter tuning requirements,deep reinforcement learning(DRL)offers a promising alternative.In the positioning stage,the Twin Delayed Deep Deterministic Policy Gradient(TD3)algorithm is employed for synchronized depth and heading control,which offers stable training,reduced overestimation bias,and superior handling of continuous control compared to other DRL methods.During the searching stage,zig-zag heading motion combined with a state-of-the-art object detection algorithm facilitates docking station localization.For the docking stage,this study proposes an innovative Image-based DDPG(I-DDPG),enhanced and trained in a Unity-MATLAB simulation environment,to achieve visual target tracking.Furthermore,integrating a DT environment enables efficient and safe policy training,reduces dependence on costly real-world tests,and improves sim-to-real transfer performance.Both simulation and real-world experiments were conducted,demonstrating the effectiveness of the system in improving AUV control strategies and supporting the transition from simulation to real-world operations in underwater environments.The results highlight the scalability and robustness of the proposed system,as evidenced by the TD3 controller achieving 25%less oscillation than the adaptive fuzzy controller when reaching the target depth,thereby demonstrating superior stability,accuracy,and potential for broader and more complex autonomous underwater tasks.
基金support from the National Natural Science Foundation of China(No.52475406)the National Key R&D Program of China(No.2022YFB3707201)+1 种基金the Key R&D Program of Shaanxi Province(No.2024CY2-GJHX-32)Ye Qisun Science Foundation of National Natural Science Foundation of China(No.U2341254)。
文摘In this work,a new strategy is proposed to improve the pseudoelasticity stability of NiTi SMAs under strains beyond the martensite transformation stress plateau by introducing homogeneous Ni_(4) Ti_(3) pre-cipitates,multiple martensite variants,and high-density austenite twins.Our experimental results show that this new strategy achieves excellent and stable pseudoelasticity with a recoverable ratio up to 85.5%larger than the highest value ever reported of 63.4%after 40 cyclic loading under a fixed strain of 14%due to the introduction of high-density austenite twins.The mechanisms of this promising property are revealed with the aid of subregional(grain boundary and grain interior)EDS,TEM,and in-situ BSE anal-ysis.First,an appropriate forging and aging process introduces homogenous Ni_(4) Ti_(3) precipitates,which reduce the energy dissipation required for one pseudoelastic loop from 4.49 to 2.48 J g^(-1) by changing the phase transformation path and temperature.Second,the high-density austenite twins induced by de-formed martensite twins during cyclic loading enhance the strength of the matrix.The reduced energy dissipation and stronger matrix improve the pseudoelasticity and its stability.We attribute these bene-ficial microstructure features to the specially designed processing routes:forging and subsequent aging.On the one hand,the dislocations induced by forging provide homogeneous nucleation sites,leading to Ni_(4) Ti_(3) homogeneously precipitating during aging;on the other hand,the dense and homogeneously dis-tributed precipitates accelerate the martensite transformation and increase the elastic modulus of the martensite,resulting in the advancement of the second stress plateau from 38%to 12%,in which part of the martensite is reoriented to generate multiple martensite variants,resulting in the formation of de-formation{113}_(B19′)martensite twin.It transforms into(112)[111]_(B2) austenite twin after unloading.These findings pave a feasible avenue for tailoring the functional properties of SMAs.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1810208 and 52401162)Shanxi province science and technology major projects,China(Grant No.20181101008).
文摘A strong basal texture is typically developed in magnesium alloy sheets that have been subjected to the rolling process.Consequently,their mechanical properties and formability are significantly impaired,which in turn restricts potential applications.In this study,an innovative texture-altering technique,which involves in-plane free compression and width-constrained rolling(FCWR),is used for AZ31 alloy sheets in order to manufacture magnesium alloy sheets with both high strength and high ductility.During FCWR deformation process,a substantial number of tensile twins and a small quantity of(1012)-(01¯12)twin-twin boundaries are induced to coordinate plastic deformation.It is precisely the presence of such crossed twins that impedes the detwinning of partial twins under low-stress conditions.The retained twins hinder the motion of dislocation,thereby enhancing the strength.Specifically,the yield strength of preset crossed twins sample along rolling direction,45°and transverse direction has increased by 105%,16.8%and 23%,respectively.Additionally,the ultimate tensile strength along these three directions has increased by 42.7%,25.5%and 34.8%,respectively.The twin boundaries in FCWR sample consist of steps,which correspond to basal-prismatic(BP/PB)boundaries that connect straight terraces which are parallel to theoretical{10¯12}twin boundaries.Furthermore,as the number of processing passes increases,the step features become more pronounced.Compared with the as-received sample,the YS enhancement in the sample prepared via the second pass of the FCWR process is attributed to two primary mechanisms:grain refinement strengthening contributes 61 MPa,while dislocation strengthening accounts for 90 MPa.
基金supported by the National Natural Science Foundation of China(Nos.52301164,52371121 and 52271107).
文摘Twins play an important role in the texture transition during annealing.In a cold rolled high rare earth content magnesium(Mg)alloys with{10–12}extension twins,{11–21}extension twins,{10–11}compression twins and{10–11}-{10–12}double twins and frequent twin-twin interactions,quasi-in-situ electron backscatter diffraction method was used to observe the twin induced static recrystallization(SRX)and related effect on texture during annealing.The results show that basal component was consumed owing to the SRX occurred in basal oriented{10–12}twins and SRXed grains with several specific orientations show preferential grain growth.SRX widely operated in the{10–12}extension and{11–21}extension twins,but absent in most{10–11}compression and{10–11}-{10–12}double twins,which is different to traditional twin induced SRX.Most compression/double twins detwinned while only partial tension twins detwinned.Operation of{11–21}twins and resultant twin-twin interaction facilitate the formation of serrated twin boundaries,which can serve as nucleation sites.Activation of<c+a>dislocation and related dislocation interaction in high dislocation density areas promote the formation of new grain boundaries and related SRX.Profuse<c+a>dislocations in basal oriented twins release the strain accumulation in compression/double twins and thus result in the absence of SRX.The twin size difference,storage energy and dislocation-twin interaction commonly functioned to the detwinning during annealing.The near-coincide site lattice boundaries that show high mobility were considered to be the important contributor to the preferential grain growth of SRXed grains.
基金supported by the National Natural Science Foundations of China[No.52374395,52474419]Natural Science Foundation of Chongqing[CSTB2024NSCQMSX0267]+6 种基金the Natural Science Foundation of Shanxi province[No.20210302123135,20210302123163]the China Postdoctoral Science Foundation[No.2022M710541]the Research Project Supported by Shanxi Scholarship Council of China[No.2022-038]Scientific and Technological Achievements Transformation Guidance Special Project of Shanxi Province[202104021301022,202204021301009]the Ministry of Science and Higher Education of the Russian Federation for financial support under the Megagrant[no.075-15-2022-1133]he National Research Foundation(NRF)grant funded by the Ministry of Science and ICT[2015R1A2A1A01006795]Korea through the Research Institute of Advanced Materials.
文摘In this work,the{10–12}tensile twins are introduced to improve the drawability of the AZ31 Mg alloy sheet.Concretely,the drawing depth is increased by 32%compared with the as-received sheet at 200℃.This is because{10–12}tensile twins promote the occurrences of many deformation mechanisms during warm deep drawing,such as slips,detwinning,dynamic recrystallization(DRX)behaviors,etc.Further,based on the different stress states during deep drawing,these mechanisms and their competition relationships,as well as texture evolutions,are systematically studied.Combined with critical resolved shear stress(CRSS)and microstructure evolution,the global Schmid factor(GSF)obtained by quantizing stress states by stress tensor(σ)can accurately predict the activation trend of deformation mechanisms.It is found that the stress states have a reverse influence on the activation trend of the{10–12}twinning and detwinning.The change of stress states affects the competitive relationships between detwinning and DRX,and then affects the process and degree of DRX.The{10–12}tensile twins and large plane strain promote the activation of prismatic slips,and the larger plane strain also deflected the{10–12}twinning lattice.The{10–12}tensile twins and their induced deformation mechanisms can prominently weaken the basal texture and improve the drawability.
