Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),fle...Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),flexible electronics(2010s,stretchable materials),and intelligent systems(2020s-present,AI-driven multimodal sensing).With the innovation of material,processing techniques,and multimodal fusion of stimuli,the application of tactile sensors has been continuously expanding to a diversity of areas,including but not limited to medical care,aerospace,sports and intelligent robots.Currently,researchers are dedicated to develop tactile sensors with emerging mechanisms and structures,pursuing high-sensitivity,high-resolution,and multimodal characteristics and further constructing tactile systems which imitate and approach the performance of human organs.However,challenges in the combination between the theoretical research and the practical applications are still significant.There is a lack of comprehensive understanding in the state of the art of such knowledge transferring from academic work to technical products.Scaled-up production of laboratory materials faces fatal challenges like high costs,small scale,and inconsistent quality.Ambient factors,such as temperature,humidity,and electromagnetic interference,also impair signal reliability.Moreover,tactile sensors must operate across a wide pressure range(0.1 k Pa to several or even dozens of MPa)to meet diverse application needs.Meanwhile,the existing algorithms,data models and sensing systems commonly reveal insufficient precision as well as undesired robustness in data processing,and there is a realistic gap between the designed and the demanded system response speed.In this review,oriented by the design requirements of intelligent tactile sensing systems,we summarize the common sensing mechanisms,inspired structures,key performance,and optimizing strategies,followed by a brief overview of the recent advances in the perspectives of system integration and algorithm implementation,and the possible roadmap of future development of tactile sensors,providing a forward-looking as well as critical discussions in the future industrial applications of flexible tactile sensors.展开更多
A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or l...A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or livelocks.The proposed method takes an uncontrolled and bounded PN model(UPNM)of the FMS.Firstly,the reduced PNM(RPNM)is obtained from the UPNM by using PN reduction rules to reduce the computation burden.Then,the set of strict minimal siphons(SMSs)of the RPNM is computed.Next,the complementary set of SMSs is computed from the set of SMSs.By the union of these two sets,the superset of SMSs is computed.Finally,the set of subnets of the RPNM is obtained by applying the PN reduction rules to the superset of SMSs.All these subnets suffer from deadlocks.These subnets are then ordered from the smallest one to the largest one based on a criterion.To enforce liveness on these subnets,a set of control places(CPs)is computed starting from the smallest subnet to the largest one.Once all subnets are live,this process provides the LES,consisting of a set of CPs to be used for the UPNM.The live controlled PN model(CPNM)is constructed by merging the LES with the UPNM.The SbDaC policy is applicable to all classes of PNs related to FMS prone to deadlocks or livelocks.Several FMS examples are considered from the literature to highlight the applicability of the SbDaC policy.In particular,three examples are utilized to emphasize the importance,applicability and effectiveness of the SbDaC policy to realistic FMS with very large state spaces.展开更多
The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,fle...The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.展开更多
BACKGROUND Humeral shaft fractures are common and vary by age,with high-energy trauma observed in younger adults and low-impact injuries in older adults.Radial nerve palsy is a frequent complication.Treatment ranges f...BACKGROUND Humeral shaft fractures are common and vary by age,with high-energy trauma observed in younger adults and low-impact injuries in older adults.Radial nerve palsy is a frequent complication.Treatment ranges from nonoperative methods to surgical interventions such as intramedullary K-wires,which promote faster rehabilitation and improved elbow mobility.AIM To evaluate the outcomes of managing humeral shaft fractures using closed reduction and internal fixation with flexible intramedullary K-wires.METHODS This was a retrospective cohort study analyzing the medical records of patients with humeral shaft fractures managed with flexible intramedullary K-wires at King Abdulaziz Medical City,using non-random sampling and descriptive analysis for outcome evaluation.RESULTS This study assessed the clinical outcomes of 20 patients treated for humeral shaft fractures with intramedullary K-wires.Patients were predominantly male(n=16,80%),had an average age of 39.2 years,and a mean body mass index of 29.5 kg/m^(2).The fractures most frequently occurred in the middle third of the humerus(n=14,70%),with oblique fractures being the most common type(n=7,35%).All surgeries used general anesthesia and a posterior approach,with no intraoperative complications reported.Postoperatively,all patients achieved clinical and radiological union(n=20,100%),and the majority(n=13,65%)reached an elbow range of motion from 0 to 150 degrees.CONCLUSION These results suggest that intramedullary K-wire fixation may be an effective option for treating humeral shaft fractures,with favorable outcomes in range of motion recovery,fracture union,and a low rate of intraoperative complications.展开更多
As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays...As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.展开更多
An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc...An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.展开更多
Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)...Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]di-hexafluorophosphate(Bn-FPV),were synthesized.These viologen derivatives as active materials were used to assemble both flexible and rigid electrochromic devices(ECDs).ECDs based on DFPV exhibited reversible color change from colorless to deep green and ECDs based on Bn-FPV exhibited reversible color change from colorless to blue-green within applied voltage.It was found that the devices based on DFPV showed cycle stability,which could still maintain more than 90% after 1000 cycles.In addition,the modulation rate of the device to the solar irradiance is also calculated to characterize its application potential in smart windows.Among them,the rigid device(R-DFPV)based on the DFPV has a large solar irradiance modulation rate of 54.66%,which has the potential to be used as smart windows.展开更多
Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with pha...Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.展开更多
Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart...Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.展开更多
Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabricati...Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.展开更多
The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these chal...The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these challenges,this work develops an artificial intelligenceassisted,wireless,flexible,and wearable mechanoluminescent strain sensor system(AIFWMLS)by integration of deep learning neural network-based color data processing system(CDPS)with a sandwich-structured flexible mechanoluminescent sensor(SFLC)film.The SFLC film shows remarkable and robust mechanoluminescent performance with a simple structure for easy fabrication.The CDPS system can rapidly and accurately extract and interpret the color of the SFLC film to strain values with auto-correction of errors caused by the varying color temperature,which significantly improves the accuracy of the predicted strain.A smart glove mechanoluminescent sensor system demonstrates the great potential of the AIFWMLS system in human gesture recognition.Moreover,the versatile SFLC film can also serve as a encryption device.The integration of deep learning neural network-based artificial intelligence and SFLC film provides a promising strategy to break the“color to strain value”bottleneck that hinders the practical application of flexible colorimetric strain sensors,which could promote the development of wearable and flexible strain sensors from laboratory research to consumer markets.展开更多
To meet the challenge of mismatches between power supply and demand,modern buildings must schedule flexible energy loads in order to improve the efficiency of power grids.Furthermore,it is essential to understand the ...To meet the challenge of mismatches between power supply and demand,modern buildings must schedule flexible energy loads in order to improve the efficiency of power grids.Furthermore,it is essential to understand the effectiveness of flexibility management strategies under different climate conditions and extreme weather events.Using both typical and extreme weather data from cities in five major climate zones of China,this study investigates the energy flexibility potential of an office building under three short-term HVAC management strategies in the context of different climates.The results show that the peak load flexibility and overall energy performance of the three short-term strategies were affected by the surrounding climate conditions.The peak load reduction rate of the pre-cooling and zone temperature reset strategies declined linearly as outdoor temperature increased.Under extreme climate conditions,the daily peak-load time was found to be over two hours earlier than under typical conditions,and the intensive solar radiation found in the extreme conditions can weaken the correlation between peak load reduction and outdoor temperature,risking the ability of a building’s HVAC system to maintain a comfortable indoor environment.展开更多
Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIB...Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.展开更多
Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals...Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals is often severely interfered by multiple factors such as background light,dark noise and circuit noise,making it difficult to accurately capture signals.While traditional technologies like silicon photomultiplier tubes excel in sensitivity,their high cost and inherent fragility restrict their widespread application.Against this background,perovskite materials have rapidly emerged as a research focus in the field of photodetection due to their simple preparation processes and exceptional optoelectronic properties.Not only are the preparation processes of perovskite materials straightforward and cost-effective,but more importantly,they can be flexibly integrated into flexible and stretchable substrates.This characteristic significantly compensates for the shortcomings of traditional rigid electronic devices in specific application scenarios,opening up entirely new possibilities for photodetection technology.Herein,recent advances in perovskite light detection technology are reviewed.Firstly,the chemical and physical properties of perovskite materials are discussed,highlighting their remarkable advantages in weak-light detection.Subsequently,the review systematically organizes various preparation techniques of perovskite materials and analyses their advantages in different application scenarios.Meanwhile,from the two core dimensions of performance improvement and light absorption enhancement,the key strategies of improving the performance of perovskite weak-light photodetectors are explored.Finally,the review concludes with a brief summary and a discussion on the potential challenges that may arise in the further development of perovskite devices.展开更多
π-Conjugated donor-acceptor-donor-acceptor-donor(D-A-D-A-D)type pyrenoviologens(PyV^(2+)),with the 2,7 positions of pyrene serving as connection bridges,were synthesized through SN2 reactions.Specifically,pyrenoviolo...π-Conjugated donor-acceptor-donor-acceptor-donor(D-A-D-A-D)type pyrenoviologens(PyV^(2+)),with the 2,7 positions of pyrene serving as connection bridges,were synthesized through SN2 reactions.Specifically,pyrenoviologen 3c was modified with a methylnaphthalene group,while 3a and 3b were modified with methyl and benzyl groups,respectively,for comparison.These pyrenoviologens exhibit reversible redox properties and strong fluorescence emission.Electrochromic devices(ECDs)were prepared using pyrenoviologens as the active materials.Notably,naphthalene-containing pyrenoviologen 3c,with its DA-D-A-D conjugated structure,possesses more stable free radicals,enabling it to maintain the radical color for a longer duration after power loss.A series of color-changing devices were successfully assembled.Due to the strong fluorescence of pyrenoviologens and the unique electron transfer effect between them and picric acid(PA),a sensor film with good selectivity and high sensitivity for PA in aqueous solution was prepared using pyrenoviologens as the fluorescent probe.Specifically,3c exhibited the highest sensitivity to PA due to its lowest energy gap.The introduction of the D-A-D-A-D structure is a strategic approach to enhancing photoelectric performance and broadening the application of viologens.展开更多
Deep-sea mineral resource transportation predominantly utilizes hydraulic pipeline methodology.Environmental factors induce vibrations in flexible pipelines,thereby affecting the internal flow characteristics.Therefor...Deep-sea mineral resource transportation predominantly utilizes hydraulic pipeline methodology.Environmental factors induce vibrations in flexible pipelines,thereby affecting the internal flow characteristics.Therefore,real-time monitoring of solid–liquid two-phase flow in pipelines is crucial for system maintenance.This study develops an autoencoder-based deep learning framework to reconstruct three-dimensional solid–liquid two-phase flow within flexible vibrating pipelines utilizing sparse wall information from sensors.Within this framework,separate X-model and F-model with distinct hidden-layer structures are established to reconstruct the coordinates and flow field information on the computational domain grid of the pipeline under traveling wave vibration.Following hyperparameter optimization,the models achieved high reconstruction accuracy,demonstrating R^(2)values of 0.990 and 0.945,respectively.The models’robustness is evaluated across three aspects:vibration parameters,physical fields,and vibration modes,demonstrating good reconstruction performance.Results concerning sensors show that 20 sensors(0.06%of total grids)achieve a balance between accuracy and cost,with superior accuracy obtained when arranged along the full length of the pipe compared to a dense arrangement at the front end.The models exhibited a signal-to-noise ratio tolerance of approximately 27 dB,with reconstruction accuracy being more affected by sensor failures at both ends of the pipeline.展开更多
The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an over...The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.展开更多
Unbalanced force produced by the unbalanced mass will affect vibrations of rotor systems,which probably results in the components failures of rotating machinery.To study the effects of unbalanced mass on the vibration...Unbalanced force produced by the unbalanced mass will affect vibrations of rotor systems,which probably results in the components failures of rotating machinery.To study the effects of unbalanced mass on the vibration characteristics of rotor systems,a flexible rotor system model considering the unbalanced mass is proposed.The time-varying bearing force is considered.The developed model is verified by the experimental and theoretical frequency spectrums.The displacements and axis orbits of flexible and rigid rotor systems are compared.The results show that the unbalanced mass will affect the vibration characteristics of rotor system.This model can be more suitable and effective to calculate vibration characteristics of rotor system with the flexible deformation and unbalanced mass.This paper provides a new reference and research method for predicting the vibrations of flexible rotor system considering the unbalanced mass.展开更多
There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and grea...There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.展开更多
This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Ham...This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Hamiltonian principle.An analysis of internal flow’s influence on the vibration characteristics of flexible marine risers is conducted.Then,for the uncertain environmental disturbance,the adaptive fuzzy logic system is introduced to dynamically approximate the boundary disturbance,and a robust adaptive fuzzy boundary control is proposed.The uniform boundedness of the closed-loop system is proved based on Lyapunov theory.The well-posedness of the closed-loop system is proved by operator semigroup theory.The proposed control’s effectiveness is validated through comparison with existing control methods.展开更多
基金the financial support of the National Natural Science Foundation of China(NO.52173028)。
文摘Since the first design of tactile sensors was proposed by Harmon in 1982,tactile sensors have evolved through four key phases:industrial applications(1980s,basic pressure detection),miniaturization via MEMS(1990s),flexible electronics(2010s,stretchable materials),and intelligent systems(2020s-present,AI-driven multimodal sensing).With the innovation of material,processing techniques,and multimodal fusion of stimuli,the application of tactile sensors has been continuously expanding to a diversity of areas,including but not limited to medical care,aerospace,sports and intelligent robots.Currently,researchers are dedicated to develop tactile sensors with emerging mechanisms and structures,pursuing high-sensitivity,high-resolution,and multimodal characteristics and further constructing tactile systems which imitate and approach the performance of human organs.However,challenges in the combination between the theoretical research and the practical applications are still significant.There is a lack of comprehensive understanding in the state of the art of such knowledge transferring from academic work to technical products.Scaled-up production of laboratory materials faces fatal challenges like high costs,small scale,and inconsistent quality.Ambient factors,such as temperature,humidity,and electromagnetic interference,also impair signal reliability.Moreover,tactile sensors must operate across a wide pressure range(0.1 k Pa to several or even dozens of MPa)to meet diverse application needs.Meanwhile,the existing algorithms,data models and sensing systems commonly reveal insufficient precision as well as undesired robustness in data processing,and there is a realistic gap between the designed and the demanded system response speed.In this review,oriented by the design requirements of intelligent tactile sensing systems,we summarize the common sensing mechanisms,inspired structures,key performance,and optimizing strategies,followed by a brief overview of the recent advances in the perspectives of system integration and algorithm implementation,and the possible roadmap of future development of tactile sensors,providing a forward-looking as well as critical discussions in the future industrial applications of flexible tactile sensors.
基金The authors extend their appreciation to King Saud University,Saudi Arabia for funding this work through the Ongoing Research Funding Program(ORF-2025-704),King Saud University,Riyadh,Saudi Arabia.
文摘A novel siphon-based divide-and-conquer(SbDaC)policy is presented in this paper for the synthesis of Petri net(PN)based liveness-enforcing supervisors(LES)for flexible manufacturing systems(FMS)prone to deadlocks or livelocks.The proposed method takes an uncontrolled and bounded PN model(UPNM)of the FMS.Firstly,the reduced PNM(RPNM)is obtained from the UPNM by using PN reduction rules to reduce the computation burden.Then,the set of strict minimal siphons(SMSs)of the RPNM is computed.Next,the complementary set of SMSs is computed from the set of SMSs.By the union of these two sets,the superset of SMSs is computed.Finally,the set of subnets of the RPNM is obtained by applying the PN reduction rules to the superset of SMSs.All these subnets suffer from deadlocks.These subnets are then ordered from the smallest one to the largest one based on a criterion.To enforce liveness on these subnets,a set of control places(CPs)is computed starting from the smallest subnet to the largest one.Once all subnets are live,this process provides the LES,consisting of a set of CPs to be used for the UPNM.The live controlled PN model(CPNM)is constructed by merging the LES with the UPNM.The SbDaC policy is applicable to all classes of PNs related to FMS prone to deadlocks or livelocks.Several FMS examples are considered from the literature to highlight the applicability of the SbDaC policy.In particular,three examples are utilized to emphasize the importance,applicability and effectiveness of the SbDaC policy to realistic FMS with very large state spaces.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051)+5 种基金Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(SKLJC-K2024-12)the Shanghai Sailing Program(23YF1402200,23YF1402400)Natural Science Foundation of Jiangsu Province(BK20240424)Taishan Scholar Foundation of Shandong Province(tsqn202408006)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University.
文摘The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.
基金approved by King Abdullah International Medical Research Center Ethics Committee(approval No.0000074524).
文摘BACKGROUND Humeral shaft fractures are common and vary by age,with high-energy trauma observed in younger adults and low-impact injuries in older adults.Radial nerve palsy is a frequent complication.Treatment ranges from nonoperative methods to surgical interventions such as intramedullary K-wires,which promote faster rehabilitation and improved elbow mobility.AIM To evaluate the outcomes of managing humeral shaft fractures using closed reduction and internal fixation with flexible intramedullary K-wires.METHODS This was a retrospective cohort study analyzing the medical records of patients with humeral shaft fractures managed with flexible intramedullary K-wires at King Abdulaziz Medical City,using non-random sampling and descriptive analysis for outcome evaluation.RESULTS This study assessed the clinical outcomes of 20 patients treated for humeral shaft fractures with intramedullary K-wires.Patients were predominantly male(n=16,80%),had an average age of 39.2 years,and a mean body mass index of 29.5 kg/m^(2).The fractures most frequently occurred in the middle third of the humerus(n=14,70%),with oblique fractures being the most common type(n=7,35%).All surgeries used general anesthesia and a posterior approach,with no intraoperative complications reported.Postoperatively,all patients achieved clinical and radiological union(n=20,100%),and the majority(n=13,65%)reached an elbow range of motion from 0 to 150 degrees.CONCLUSION These results suggest that intramedullary K-wire fixation may be an effective option for treating humeral shaft fractures,with favorable outcomes in range of motion recovery,fracture union,and a low rate of intraoperative complications.
基金supported by Youth Talent Project of Scientific Research Program of Hubei Provincial Department of Education under Grant Q20241809Doctoral Scientific Research Foundation of Hubei University of Automotive Technology under Grant 202404.
文摘As Internet of Things(IoT)applications expand,Mobile Edge Computing(MEC)has emerged as a promising architecture to overcome the real-time processing limitations of mobile devices.Edge-side computation offloading plays a pivotal role in MEC performance but remains challenging due to complex task topologies,conflicting objectives,and limited resources.This paper addresses high-dimensional multi-objective offloading for serial heterogeneous tasks in MEC.We jointly consider task heterogeneity,high-dimensional objectives,and flexible resource scheduling,modeling the problem as a Many-objective optimization.To solve it,we propose a flexible framework integrating an improved cooperative co-evolutionary algorithm based on decomposition(MOCC/D)and a flexible scheduling strategy.Experimental results on benchmark functions and simulation scenarios show that the proposed method outperforms existing approaches in both convergence and solution quality.
基金Open access funding provided by FCT|FCCN(b-on)the Strategic Research Plan of the Centre for Marine Technology and Ocean Engineering(CENTEC),which is financed by the Portuguese Foundation for Science and Technology(Fundação para a Ciência e Tecnologia-FCT)under contract UIDB/UIDP/00134/2020.
文摘An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones.
基金Funded by the Natural Science Foundation of Guangdong(Nos.2014A030313241,2014B090901068,and 2016A010103003)。
文摘Two viologen derivatives containing fluorine substituent(F)with an asymmetric structures,1,1'-bis(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]dihexafluorophosphate(DFPV)and 1-benzyl-1'-(4-(trifluoromethyl)phenyl)-[4,4'-bipyridine]di-hexafluorophosphate(Bn-FPV),were synthesized.These viologen derivatives as active materials were used to assemble both flexible and rigid electrochromic devices(ECDs).ECDs based on DFPV exhibited reversible color change from colorless to deep green and ECDs based on Bn-FPV exhibited reversible color change from colorless to blue-green within applied voltage.It was found that the devices based on DFPV showed cycle stability,which could still maintain more than 90% after 1000 cycles.In addition,the modulation rate of the device to the solar irradiance is also calculated to characterize its application potential in smart windows.Among them,the rigid device(R-DFPV)based on the DFPV has a large solar irradiance modulation rate of 54.66%,which has the potential to be used as smart windows.
基金supported by the National Natural Science Foundation of China (Grant Nos.12274313 and 62375234)the Gusu Leading Talent Plan for Scientific and Technological Innovation and Entrepreneurship (Grant No.ZXL2024400)。
文摘Optical phase-gradient metasurfaces have garnered significant attention for enabling flexible light manipulation,with applications across diverse domains.In this work,we will demonstrate that the metasurfaces with phase gradient modulation can be used to achieve illusion optics,featuring the advantages of simple geometric structure and feasible implementation compared with the well-known transformation optics method.The underlying mechanism is the anomalous diffraction law caused by the phase gradient,which provides a theoretical basis for freely manipulating the propagation path of light.By considering a specific example,we will demonstrate that the phase gradient can transform spatial coordinates in real space into illusion space,thereby converting a plane in real space into a curved surface structure in illusion space to achieve the illusion effect.This approach provides a viable alternative to transformation optics for designing illusion devices.
基金supported by the National Natural Science Foundation of China(No.22376159)the Fundamental Research Funds for the Central Universities.
文摘Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.
基金supported by the National Key R&D Plan of China(Grant No.2023YFB3210400)the National Natural Science Foundation of China(No.62174101)+2 种基金the Major Scientific and Technological Innovation Project of Shandong Province(2021CXGC010603)the Fundamental Research Funds of Shandong University(2020QNQT001)Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of Shandong,the Natural Science Foundation of Qingdao-Original exploration project(No.24-4-4-zrjj-139-jch).
文摘Flexible electronics are transforming our lives by making daily activities more convenient.Central to this innovation are field-effect transistors(FETs),valued for their efficient signal processing,nanoscale fabrication,low-power consumption,fast response times,and versatility.Graphene,known for its exceptional mechanical properties,high electron mobility,and biocompatibility,is an ideal material for FET channels and sensors.The combination of graphene and FETs has given rise to flexible graphene field-effect transistors(FGFETs),driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors.Here,we first provide a brief overview of the basic structure,operating mechanism,and evaluation parameters of FGFETs,and delve into their material selection and patterning techniques.The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities.We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors,focusing on the key aspects of constructing high-quality flexible biomedical sensors.Finally,we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors.This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing.
基金funded by the National Natural Science Foundation of China(52475580)the Special Foundation of the Taishan Scholar Project(tsqn202211077,tsqn202311077)+3 种基金Shandong Provincial Excellent Overseas Young Scholar Foundation(2023HWYQ-069)the Shandong Provincial Natural Science Foundation(ZR2023ME118,ZR2023QF080)the Natural Science Foundation of Qingdao City(23-2-1-219-zyyd-jch,23-2-1-111-zyyd-jch)the Fundamental Research Funds for the Central Universities(23CX06032A).
文摘The complex wiring,bulky data collection devices,and difficulty in fast and on-site data interpretation significantly limit the practical application of flexible strain sensors as wearable devices.To tackle these challenges,this work develops an artificial intelligenceassisted,wireless,flexible,and wearable mechanoluminescent strain sensor system(AIFWMLS)by integration of deep learning neural network-based color data processing system(CDPS)with a sandwich-structured flexible mechanoluminescent sensor(SFLC)film.The SFLC film shows remarkable and robust mechanoluminescent performance with a simple structure for easy fabrication.The CDPS system can rapidly and accurately extract and interpret the color of the SFLC film to strain values with auto-correction of errors caused by the varying color temperature,which significantly improves the accuracy of the predicted strain.A smart glove mechanoluminescent sensor system demonstrates the great potential of the AIFWMLS system in human gesture recognition.Moreover,the versatile SFLC film can also serve as a encryption device.The integration of deep learning neural network-based artificial intelligence and SFLC film provides a promising strategy to break the“color to strain value”bottleneck that hinders the practical application of flexible colorimetric strain sensors,which could promote the development of wearable and flexible strain sensors from laboratory research to consumer markets.
基金National Key R&D Program of China of the 13th Five-Year Plan(No.2018YFD1100704)。
文摘To meet the challenge of mismatches between power supply and demand,modern buildings must schedule flexible energy loads in order to improve the efficiency of power grids.Furthermore,it is essential to understand the effectiveness of flexibility management strategies under different climate conditions and extreme weather events.Using both typical and extreme weather data from cities in five major climate zones of China,this study investigates the energy flexibility potential of an office building under three short-term HVAC management strategies in the context of different climates.The results show that the peak load flexibility and overall energy performance of the three short-term strategies were affected by the surrounding climate conditions.The peak load reduction rate of the pre-cooling and zone temperature reset strategies declined linearly as outdoor temperature increased.Under extreme climate conditions,the daily peak-load time was found to be over two hours earlier than under typical conditions,and the intensive solar radiation found in the extreme conditions can weaken the correlation between peak load reduction and outdoor temperature,risking the ability of a building’s HVAC system to maintain a comfortable indoor environment.
文摘Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.
文摘Photodetectors with weak-light detection capabilities play an indispensable role in various crucial fields such as health monitors,imaging,optical communication,and etc.Nevertheless,the detection of weak light signals is often severely interfered by multiple factors such as background light,dark noise and circuit noise,making it difficult to accurately capture signals.While traditional technologies like silicon photomultiplier tubes excel in sensitivity,their high cost and inherent fragility restrict their widespread application.Against this background,perovskite materials have rapidly emerged as a research focus in the field of photodetection due to their simple preparation processes and exceptional optoelectronic properties.Not only are the preparation processes of perovskite materials straightforward and cost-effective,but more importantly,they can be flexibly integrated into flexible and stretchable substrates.This characteristic significantly compensates for the shortcomings of traditional rigid electronic devices in specific application scenarios,opening up entirely new possibilities for photodetection technology.Herein,recent advances in perovskite light detection technology are reviewed.Firstly,the chemical and physical properties of perovskite materials are discussed,highlighting their remarkable advantages in weak-light detection.Subsequently,the review systematically organizes various preparation techniques of perovskite materials and analyses their advantages in different application scenarios.Meanwhile,from the two core dimensions of performance improvement and light absorption enhancement,the key strategies of improving the performance of perovskite weak-light photodetectors are explored.Finally,the review concludes with a brief summary and a discussion on the potential challenges that may arise in the further development of perovskite devices.
基金supported by the Shaanxi Province Technological Innovation Guidance Special(No.2022QFY08-01)the National Key Research and Development Program of China(No.2021YFB3200702)+5 种基金Natural Science Foundation of China(Nos.22201228,22205172,52203240 and 22175138)China Postdoctoral Science Foundation(Nos.2022M712530,2023T160506,and 2022M712497)Fundamental Research Funds for the Central Universities(No.xzy012022017)Young Talent Fund of Association for Science and Technology in Shaanxi(No.20230624)Shaanxi Province Postdoctoral Science Foundation(No.2023b SHTBZZ04)the Youth Innovation Team of Shaanxi Universities。
文摘π-Conjugated donor-acceptor-donor-acceptor-donor(D-A-D-A-D)type pyrenoviologens(PyV^(2+)),with the 2,7 positions of pyrene serving as connection bridges,were synthesized through SN2 reactions.Specifically,pyrenoviologen 3c was modified with a methylnaphthalene group,while 3a and 3b were modified with methyl and benzyl groups,respectively,for comparison.These pyrenoviologens exhibit reversible redox properties and strong fluorescence emission.Electrochromic devices(ECDs)were prepared using pyrenoviologens as the active materials.Notably,naphthalene-containing pyrenoviologen 3c,with its DA-D-A-D conjugated structure,possesses more stable free radicals,enabling it to maintain the radical color for a longer duration after power loss.A series of color-changing devices were successfully assembled.Due to the strong fluorescence of pyrenoviologens and the unique electron transfer effect between them and picric acid(PA),a sensor film with good selectivity and high sensitivity for PA in aqueous solution was prepared using pyrenoviologens as the fluorescent probe.Specifically,3c exhibited the highest sensitivity to PA due to its lowest energy gap.The introduction of the D-A-D-A-D structure is a strategic approach to enhancing photoelectric performance and broadening the application of viologens.
基金financial support by the National Natural Science Foundation of China (Nos.52471293 and 12372270)the National Youth Science Foundation of China (Nos.52101322 and 52108375)+3 种基金the Program for Intergovernmental International S&T Cooperation Projects of Shanghai Municipality, China (Nos.24510711100 and 22160710200)The Oceanic Interdisciplinary Program of Shanghai Jiao Tong University (No.SL2022PT101)funded by the Open Fund of the State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology (No.LP2415)National Key R&D Program of China (No.2023YFC2811600)
文摘Deep-sea mineral resource transportation predominantly utilizes hydraulic pipeline methodology.Environmental factors induce vibrations in flexible pipelines,thereby affecting the internal flow characteristics.Therefore,real-time monitoring of solid–liquid two-phase flow in pipelines is crucial for system maintenance.This study develops an autoencoder-based deep learning framework to reconstruct three-dimensional solid–liquid two-phase flow within flexible vibrating pipelines utilizing sparse wall information from sensors.Within this framework,separate X-model and F-model with distinct hidden-layer structures are established to reconstruct the coordinates and flow field information on the computational domain grid of the pipeline under traveling wave vibration.Following hyperparameter optimization,the models achieved high reconstruction accuracy,demonstrating R^(2)values of 0.990 and 0.945,respectively.The models’robustness is evaluated across three aspects:vibration parameters,physical fields,and vibration modes,demonstrating good reconstruction performance.Results concerning sensors show that 20 sensors(0.06%of total grids)achieve a balance between accuracy and cost,with superior accuracy obtained when arranged along the full length of the pipe compared to a dense arrangement at the front end.The models exhibited a signal-to-noise ratio tolerance of approximately 27 dB,with reconstruction accuracy being more affected by sensor failures at both ends of the pipeline.
基金the support from the National Natural Science Foundation of China(22272004,62272041)the Fundamental Research Funds for the Central Universities(YWF-22-L-1256)+1 种基金the National Key R&D Program of China(2023YFC3402600)the Beijing Institute of Technology Research Fund Program for Young Scholars(No.1870011182126)。
文摘The proliferation of wearable biodevices has boosted the development of soft,innovative,and multifunctional materials for human health monitoring.The integration of wearable sensors with intelligent systems is an overwhelming tendency,providing powerful tools for remote health monitoring and personal health management.Among many candidates,two-dimensional(2D)materials stand out due to several exotic mechanical,electrical,optical,and chemical properties that can be efficiently integrated into atomic-thin films.While previous reviews on 2D materials for biodevices primarily focus on conventional configurations and materials like graphene,the rapid development of new 2D materials with exotic properties has opened up novel applications,particularly in smart interaction and integrated functionalities.This review aims to consolidate recent progress,highlight the unique advantages of 2D materials,and guide future research by discussing existing challenges and opportunities in applying 2D materials for smart wearable biodevices.We begin with an in-depth analysis of the advantages,sensing mechanisms,and potential applications of 2D materials in wearable biodevice fabrication.Following this,we systematically discuss state-of-the-art biodevices based on 2D materials for monitoring various physiological signals within the human body.Special attention is given to showcasing the integration of multi-functionality in 2D smart devices,mainly including self-power supply,integrated diagnosis/treatment,and human–machine interaction.Finally,the review concludes with a concise summary of existing challenges and prospective solutions concerning the utilization of2D materials for advanced biodevices.
基金Support by Shanxi Provincial Key Research and Development Plan of China(Grant No.2024GH-ZDXM-29)National Natural Science Foundation of China(Grant No.52175120)Shaanxi Provincial Innovation Capability Support Program of China(Grant No.2024RS-CXTD-15)。
文摘Unbalanced force produced by the unbalanced mass will affect vibrations of rotor systems,which probably results in the components failures of rotating machinery.To study the effects of unbalanced mass on the vibration characteristics of rotor systems,a flexible rotor system model considering the unbalanced mass is proposed.The time-varying bearing force is considered.The developed model is verified by the experimental and theoretical frequency spectrums.The displacements and axis orbits of flexible and rigid rotor systems are compared.The results show that the unbalanced mass will affect the vibration characteristics of rotor system.This model can be more suitable and effective to calculate vibration characteristics of rotor system with the flexible deformation and unbalanced mass.This paper provides a new reference and research method for predicting the vibrations of flexible rotor system considering the unbalanced mass.
基金supported by the Basic Research Development Program of China(No.JCKY2021607B036)the National Natural Science Foundation of China(No.52275512).
文摘There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.
基金financially supported by Sichuan Science and Technology Program(Grant No.2023NSFSC1980).
文摘This study examines the adaptive boundary control problem of flexible marine riser with internal flow coupling.The dynamic model of the flexible marine riser system with internal flow coupling is derived using the Hamiltonian principle.An analysis of internal flow’s influence on the vibration characteristics of flexible marine risers is conducted.Then,for the uncertain environmental disturbance,the adaptive fuzzy logic system is introduced to dynamically approximate the boundary disturbance,and a robust adaptive fuzzy boundary control is proposed.The uniform boundedness of the closed-loop system is proved based on Lyapunov theory.The well-posedness of the closed-loop system is proved by operator semigroup theory.The proposed control’s effectiveness is validated through comparison with existing control methods.
