A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nit...A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nitrogen doping.This achievement notably overcomes the inherent constraints of conventional metal-based absorbers,including low resonance frequency,high conductivity,and elevated density,for the synergistic advantages provided by multimetallic alloys and foams.Microstructural analysis with comprehensive theoretical calculations provides in-depth insights into the formation mechanism,electronic structure,and magnetic moment of MEANFs.Furthermore,deliberate component design along with the foam structure proves to be an effective strategy for enhancing impedance matching and absorption.The results show that the MEANFs exhibit a minimum reflection loss(RL_(min))value of-60.32 dB and a maximum effective absorption bandwidth(EAB_(max))of 5.28 GHz at 1.69 mm.This augmentation of energy dissipation in EMW is predominantly attributed to factors such as porous structure,interfacial polarization,defect-induced polarization,and magnetic resonance.This study demonstrates a facile and efficient approach for synthesizing single-phase medium-entropy alloys,emphasizing their potential as materials for electromagnetic wave absorption due to their adjustable magnetic-dielectric properties.展开更多
The critical components of gas turbines suffer from prolonged exposure to factors such as thermal oxidation,mechanical wear,and airflow disturbances during prolonged operation.These conditions can lead to a series of ...The critical components of gas turbines suffer from prolonged exposure to factors such as thermal oxidation,mechanical wear,and airflow disturbances during prolonged operation.These conditions can lead to a series of issues,including mechanical faults,air path malfunctions,and combustion irregularities.Traditional modelbased approaches face inherent limitations due to their inability to handle nonlinear problems,natural factors,measurement uncertainties,fault coupling,and implementation challenges.The development of artificial intelligence algorithms has provided an effective solution to these issues,sparking extensive research into data-driven fault diagnosis methodologies.The review mechanism involved searching IEEE Xplore,ScienceDirect,and Web of Science for peerreviewed articles published between 2019 and 2025,focusing on multi-fault diagnosis techniques.A total of 220 papers were identified,with 123 meeting the inclusion criteria.This paper provides a comprehensive review of diagnostic methodologies,detailing their operational principles and distinctive features.It analyzes current research hotspots and challenges while forecasting future trends.The study systematically evaluates the strengths and limitations of various fault diagnosis techniques,revealing their practical applicability and constraints through comparative analysis.Furthermore,this paper looks forward to the future development direction of this field and provides a valuable reference for the optimization and development of gas turbine fault diagnosis technology in the future.展开更多
Deadlock avoidance problems are investigated for automated manufacturing systems with flexible routings. Based on the Petri net models of the systems, this paper proposes, for the first time, the concept of perfect ma...Deadlock avoidance problems are investigated for automated manufacturing systems with flexible routings. Based on the Petri net models of the systems, this paper proposes, for the first time, the concept of perfect maximal resourcetransition circuits and their saturated states. The concept facilitates the development of system liveness characterization and deadlock avoidance Petri net supervisors. Deadlock is characterized as some perfect maximal resource-transition circuits reaching their saturated states. For a large class of manufacturing systems, which do not contain center resources, the optimal deadlock avoidance Petri net supervisors are presented. For a general manufacturing system, a method is proposed for reducing the system Petri net model so that the reduced model does not contain center resources and, hence, has optimal deadlock avoidance Petri net supervisor. The controlled reduced Petri net model can then be used as the liveness supervisor of the system.展开更多
This paper investigates the stochastic bounded consensus of leader-following second-order multi-agent systems in a noisy environment. It is assumed that each agent received the information of its neighbors corrupted b...This paper investigates the stochastic bounded consensus of leader-following second-order multi-agent systems in a noisy environment. It is assumed that each agent received the information of its neighbors corrupted by noises and time delays. Based on the graph theory, stochastic tools, and the Lyapunov function method, we derive the sufficient conditions under which the systems would reach stochastic bounded consensus in mean square with the protocol we designed. Finally, a numerical simulation is illustrated to check the effectiveness of the proposed algorithms.展开更多
The problem of delay-dependent exponential stability is investigated for impulsive stochastic systems with time-varying delay. Although the exponential stability of impulsive stochastic delay systems has been discusse...The problem of delay-dependent exponential stability is investigated for impulsive stochastic systems with time-varying delay. Although the exponential stability of impulsive stochastic delay systems has been discussed by several authors, few works have been done on delay-dependent exponential stability of impulsive stochastic delay systems. Firstly, the Lyapunov-Krasovskii functional method combing the free-weighting matrix approach is applied to investigate this problem. Some delay-dependent mean square exponential stability criteria are derived in terms of linear matrix inequalities. In particular, the estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive effects. The obtained results show that the system will stable if the impulses＇ frequency and amplitude are suitably related to the increase or decrease of the continuous flows, and impulses may be used as controllers to stabilize the underlying stochastic system. Numerical examples are given to show the effectiveness of the results.展开更多
Safe and efficient sortie scheduling on the confined flight deck is crucial for maintaining high combat effectiveness of the aircraft carrier.The primary difficulty exactly lies in the spatiotemporal coordination,i.e....Safe and efficient sortie scheduling on the confined flight deck is crucial for maintaining high combat effectiveness of the aircraft carrier.The primary difficulty exactly lies in the spatiotemporal coordination,i.e.,allocation of limited supporting resources and collision-avoidance between heterogeneous dispatch entities.In this paper,the problem is investigated in the perspective of hybrid flow-shop scheduling problem by synthesizing the precedence,space and resource constraints.Specifically,eight processing procedures are abstracted,where tractors,preparing spots,catapults,and launching are virtualized as machines.By analyzing the constraints in sortie scheduling,a mixed-integer planning model is constructed.In particular,the constraint on preparing spot occupancy is improved to further enhance the sortie efficiency.The basic trajectory library for each dispatch entity is generated and a delayed strategy is integrated to address the collision-avoidance issue.To efficiently solve the formulated HFSP,which is essentially a combinatorial problem with tightly coupled constraints,a chaos-initialized genetic algorithm is developed.The solution framework is validated by the simulation environment referring to the Fort-class carrier,exhibiting higher sortie efficiency when compared to existing strategies.And animation of the simulation results is available at www.bilibili.com/video/BV14t421A7Tt/.The study presents a promising supporting technique for autonomous flight deck operation in the foreseeable future,and can be easily extended to other supporting scenarios,e.g.,ammunition delivery and aircraft maintenance.展开更多
Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence i...Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence immunoassay system was designed.We encapsulated carbon dots with a high fluorescence quantum yield(QY=92.5%)inside silicon nanocapsules to serve as fluorescent markers.These markers were then integrated with the streptavidin(SA)-biotin biomagnification system and immunomagnetic separation technology for the sensitive detection of GFAP.Based on the signal cascade amplification effect of the silicon nanocapsules and SA-biotin,the fluorescence signal of the SA-biotin-modified immunofluorescence nanocapsules increased 3.6-fold compared to the carbon dot-based immunoprobe.The fluorescence immunoassay system was constructed for GFAP using SA-biotin-modified immunocapsules as the sensing probe and immunomagnetic nanoparticles as the immunorecognition probe.The fluorescence immunoassay system can specifically and ultra-sensitively quantify GFAP in blood samples,with a detection range of 10 pg/mL–10 ng/mL and detection limits of 3.2 pg/mL(serum)and 3.6 pg/mL(plasma).Moreover,the fluorescence immunoassay system exhibited prominent recoveries of 99.4%–100.4%(phosphate buffered saline),96%–102.6%(serum),and 93.2%–110.2%(plasma),with favorable specificity and excellent stabilization.The novel fluorescence immunoassay system provides a new approach to the clinical analysis of GFAP and may serve as a potential tool for screening and diagnosing TBI.展开更多
In wireless communication scenarios,especially in low-bandwidth or noisy transmission conditions,image data is often degraded by interference during acquisition or transmission.To address this,we proposed Wasserstein ...In wireless communication scenarios,especially in low-bandwidth or noisy transmission conditions,image data is often degraded by interference during acquisition or transmission.To address this,we proposed Wasserstein frequency generative adversarial networks(WF-GAN),a frequency-aware denoising model based on wavelet transformation.By decomposing images into four frequency sub-bands,the model separates low-frequency contour information from high-frequency texture details.Contour guidance is applied to preserve structural integrity,while adversarial training enhances texture fidelity in the high-frequency bands.A joint loss function,incorporating frequency-domain loss and perceptual loss,is designed to reduce detail degradation during denoising.Experiments on public image datasets,with Gaussian noise applied to simulate wireless communication interference,demonstrate that WF-GAN consistently outperforms both traditional and deep learning-based denoising methods in terms of visual quality and quantitative metrics.These results highlight its potential for robust image processing in wireless communication systems.展开更多
Microbial food is an important direction of sustainable food development in the future.Microorganisms such as lactic acid bacteria(LAB)are important sources of natural radioprotectors.Moderate environmental stress can...Microbial food is an important direction of sustainable food development in the future.Microorganisms such as lactic acid bacteria(LAB)are important sources of natural radioprotectors.Moderate environmental stress can induce stress response and improve biological activity of LAB.In the previous study,Lactococcus lactis subsp.lactis IL1403(L.lactis IL1403)cell-free extract induced by ionizing radiation(IR)of 500 Gy(IR-CFE)presented the stronger radioprotective effect than untreated cell-free extract in mice.To explore the radioprotective active substances of IR-CFE,the key protein was screened by proteomics and its radioprotective effect in vivo was further evaluated.The Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment showed that two-component systems(TCS)were enhanced to adapt the IR induction.Meanwhile,the protein LlrG belonged to TCS was screened by the protein-protein interaction.Furthermore,the recombinant protein LlrG(rLlrG)could markedly alleviate the ^(60)Coγ-induced damage to the hematopoietic system,oxidative stress and inflammation in mice,thereby exerting its radioprotective function.These results suggested LlrG protein not only played an important role in the adaptation of L.lactis IL1403 to IR environment,but also exerted a good radioprotective effect,which could be applied in the development of protein-based radioprotectors.展开更多
Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These de...Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These densely arranged particles with a consistent planar orientation significantly enhance the soft magnetic properties of SMCs,including high permeability and low magnetic losses.The internal structures of the composites and microstructure evolution of the flaky nanocrystalline particles during the hot-pressing process have been thoroughly studied.Moreover,systematic investigations into the effects of coatings and particle sizes on the maximum permeability and magnetic losses of the composites are conducted.The SMC prepared using the coated particles with a size of 0-100μm exhibits a high maximum perme-ability of 2170(at 1000 Hz)and low magnetic loss of 41.61 W kg^(-1)(at 1000 Hz and 1.0 T).The losses and permeability analysis reveal that the superior performance of these soft magnetic materials is attributed to their laminated structure,insulation coating,and the reduced planar demagnetizing factor.Compared to the traditional silicon steel,this novel SMCs exhibits high magnetic permeability and reduced magnetic losses at frequencies above 1000 Hz,which possess immense application potential within high-frequency electric machines.展开更多
Deep neural networks,especially face recognition models,have been shown to be vulnerable to adversarial examples.However,existing attack methods for face recognition systems either cannot attack black-box models,are n...Deep neural networks,especially face recognition models,have been shown to be vulnerable to adversarial examples.However,existing attack methods for face recognition systems either cannot attack black-box models,are not universal,have cumbersome deployment processes,or lack camouflage and are easily detected by the human eye.In this paper,we propose an adversarial pattern generation method for face recognition and achieve universal black-box attacks by pasting the pattern on the frame of goggles.To achieve visual camouflage,we use a generative adversarial network(GAN).The scale of the generative network of GAN is increased to balance the performance conflict between concealment and adversarial behavior,the perceptual loss function based on VGG19 is used to constrain the color style and enhance GAN’s learning ability,and the fine-grained meta-learning adversarial attack strategy is used to carry out black-box attacks.Sufficient visualization results demonstrate that compared with existing methods,the proposed method can generate samples with camouflage and adversarial characteristics.Meanwhile,extensive quantitative experiments show that the generated samples have a high attack success rate against black-box models.展开更多
This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing chara...This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing characteristics is revealed,and an energy-efficient zoned electric heating anti-icing strategy is proposed.A threedimensional grille model is constructed to systematically analyze the effects of environmental temperature(from−20℃to−4℃),droplet diameter(from 50μm to 500μm),and liquid water content(from 0.5 g/m³to 8 g/m³)on icing rates and blockage of the flow channel.The results indicate that low temperature and high liquid water content significantly exacerbate icing.Under the condition of an environmental temperature of−20℃,droplet diameter of 500μm,and liquid water content of 8 g/m³,the flow channel blockage ratio reaches 30.95%within 10 min.Additionally,as droplet diameter increases,the droplet impingement and icing regions become more concentrated toward the leading edge of blades.To mitigate grille icing in cold environments,an electric heating film configuration is employed for thermal protection.Optimization of the heating strategy reveals that the zoned heating approach,compared to the initial uniform heating scheme,effectively homogenizes surface temperature distribution while reducing total power consumption by 37.47%.This study validates the engineering applicability of the zoned electric heating anti/de-icing strategy,providing theoretical and technical support for the design of anti-icing systems in ship power systems operating in cold maritime regions.展开更多
Despite significant progress in the structure and properties of porous absorbing materials,major challenges remain due to complex preparation technology,high production costs,and poor corrosion resistance.In this stud...Despite significant progress in the structure and properties of porous absorbing materials,major challenges remain due to complex preparation technology,high production costs,and poor corrosion resistance.In this study,nanowires were used as the substrate,liquid nitrogen controls ice crystal growth orientation,and ammonia gas facilitates the generation of magnetic substances.The resulting pure magnetic porous foam(PMF)material exhibits enhanced performance in absorbing electromagnetic waves(EMWs)and improved corrosion resistance.The PMF's microstructure was analyzed for its dielectric and magnetic loss characteristics.The PMF combines a porous framework,nanoscale architecture,and exclusive magnetic components to create a lightweight foam absorbent material with enhanced magnetic dissipation capabilities.Among them,the Fe_(4)N PMF demonstrates an impressive minimum reflection loss(RLmin)value of−66.8 dB at a thickness of 1.09 mm,exhibits an effective absorption bandwidth of 4.00 GHz,and shows exceptional corrosion resistance with a self-corrosion potential of−0.65 V.Moreover,the effectiveness of the Fe_(4)N PMF in absorbing intelligent EMWs has been validated through radar cross-section(RCS)simulations.In summary,this study has developed electromagnetic wave-absorbing materials with slim profiles,lightweight properties,strong absorption capabilities,and excellent corrosion resistance.These characteristics make them highly promising for microwave absorption applications.展开更多
The total replacement of old fossil fuels poses obstacles,making the production of efficient biogasoline vital.Despite its potential as an environmentally friendly fossil fuel substitute,the life cycle assessment(LCA)...The total replacement of old fossil fuels poses obstacles,making the production of efficient biogasoline vital.Despite its potential as an environmentally friendly fossil fuel substitute,the life cycle assessment(LCA)of palm oil-derived biogasoline remains underexplored.This study investigated the production of biogasoline fromcrude palm oil(CPO)based biorefinery using catalytic cracking over mesoporousγ-Al_(2)O_(3) catalyst and LCA analysis.High selectivity of converting CPO into biogasoline was achieved by optimizing catalytic cracking parameters,including catalyst dose,temperature,and contact time.γ-Al_(2)O_(3) and CPO were characterized by several methods to study the physical and chemical properties.The physical properties of biogasoline,such as density,calorific value,viscosity,and flash point,were investigated.An overall yield of 60.11%was achieved after catalytic cracking produced several C5-C11 short-chain hydrocarbons.Additionally,this research proposes innovative emission reduction strategies,including waste-to-biogasoline conversion and the use of biodegradable feedstocks that enhance the sustainability of biogasoline production.LCA ofγ-Al_(2)O_(3)’s energy and environmental implications reveals minor effects on global warming(0.0068%)and freshwater ecotoxicity(0.187%).LCAs show a 0.085%impact in the energy sector.This focus on both ecological impacts and practical mitigation strategies deepens the understanding of biogasoline production.展开更多
Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed th...Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed that the global channel state information(CSI)of the eavesdroppers(Eves)was known beforehand,then the optimal relaying and jamming relays were determined.More importantly,the time complexity of selecting optimal jamming relay is O(N^(2)),where N is the maximum number of relays/Eves.In this paper,for the scenario where the source wants to exchange the message with the destination,via relaying scheme due to longer communication distance and limited transmission power,in the presence of multiple Eves,with the assumption of Eves'perfect CSI and average CSI,we propose two kinds of JRJS methods.In particular,the time complexity of finding the optimal jammer can be reduced to O(N).Furthermore,we present a novel JRJS scheme for no CSI of Eves by minimizing the difference between expected signal and interfering signal at the destination.Finally,simulations show that the designed methods are more effective than JRJS and other existing strategies in terms of security performance.展开更多
As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger rig...As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger righting moment than a common single T-foil system.One T-foil is mounted at the bow,and the other at the stern.Accordingly,different control strategies for dual T-foils were proposed To verify the stratigies,a model experiment was conducted in the Towing Tank,Dalian Unievrsity of Technology.The optimal control signal was determined by comparing the pitch responses,heave responses,bow accelerations,and stern accelerations of a vessel in regular waves.In addition,the control strategy for the best motion-reduction effect was investigated.The optimized dual T-foil system provides a 34%reduction in pitch motion.展开更多
In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.T...In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.The control accuracy of ISP is fundamentally circumscribed by various disturbance torques in rotating shaft.Therefore,a dynamic model of ISP incorporating composite perturbations is established with regard to the stabilization of axis in the inertial reference frame.Subsequently,an online estimator for control loop uncertainties based on the sliding mode control algorithm is designed to estimate the aggregate disturbances of various parameters uncertainties and other unmodeled disturbances that cannot be accurately calibrated.Finally,the proposed DSMO is integrated into a classical proportional-integral-derivative(PID)control scheme,utilizing feedforward approach to compensate the composite disturbance in the control loop online.The effectiveness of the proposed disturbance observer is validated through simulation and hardware experimentation,demonstrating a significant improvement in the dynamic control performance and robustness of the classical PID controller extensively utilized in the field of engineering.展开更多
Recovery is a crucial supporting process for carrier aircraft,where a reasonable landing scheduling is expected to guide the fleet landing safely and quickly.Currently,there is little research on this topic,and most o...Recovery is a crucial supporting process for carrier aircraft,where a reasonable landing scheduling is expected to guide the fleet landing safely and quickly.Currently,there is little research on this topic,and most of it neglects potential influence factors,leaving the corresponding supporting efficiency questionable.In this paper,we study the landing scheduling problem for carrier aircraft considering the effects of bolting and aerial refueling.Based on the analysis of recovery mode involving the above factors,two types of primary constraints(i.e.,fuel constraint and wake interval constraint)are first described.Then,taking the landing sequencing as decision variables,a combinatorial optimization model with a compound objective function is formulated.Aiming at an efficient solution,an improved firefly algorithm is designed by integrating multiple evolutionary operators.In addition,a dynamic replanning mechanism is introduced to deal with special situations(i.e.,the occurrence of bolting and fuel shortage),where the high efficiency of the designed algorithm facilitates the online scheduling adjustment within seconds.Finally,numerical simulations with sufficient and insufficient fuel cases are both carried out,highlighting the necessity to consider bolting and aerial refueling during the planning procedure.Simulation results reveal that a higher bolting probability,as well as extra aerial refueling operations caused by fuel shortage,will lead to longer recovery complete time.Meanwhile,due to the strong optimum-seeking capability and solution efficiency of the improved algorithm,adaptive scheduling can be generated within milliseconds to deal with special situations,significantly improving the safety and efficiency of the recovery process.An animation is accessible at bilibili.com/video/BV1QprKY2EwD.展开更多
With the increasing concerns about energy consumption and environmental protection, minimizing energy consumption while ensuring desired productivity becomes more and more important in flexible assembly systems(FASs) ...With the increasing concerns about energy consumption and environmental protection, minimizing energy consumption while ensuring desired productivity becomes more and more important in flexible assembly systems(FASs) design and operation. However, because of the complexity of deadlock-prone FASs, only a few researchers have addressed their scheduling problems. Besides, no existing literature in the field of scheduling of deadlock-prone FASs takes energy consumption minimization as the optimization criterion to our best knowledge. This paper presents an A^(*)-based hybrid heuristic search algorithm to minimize the total energy consumption of FASs with tool change processes. Based on a developed Petri net(PN) model, two energy functions are proposed to calculate the energy consumption of FASs. To achieve better performance, six new heuristic functions are designed to guide the search process by considering the features of FASs. Besides, two selection functions are proposed to evaluate the prospects of vertexes and choose the promising ones.Moreover, a dynamic window is applied in the algorithm to limit the search space, and a deadlock prevention policy is used to ensure feasible schedules. Experimental results show that the proposed algorithm can effectively find feasible schedules for FASs,and a well-designed heuristic function is likely to obtain schedules to meet industrial application requirements.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52071294)the National Key Research and Development Program(Grant No.2022YFE0109800)the Natural Science Foundation of Zhejiang Province(Grant No.LY20E020015).
文摘A single-phase anti-perovskite medium-entropy alloy nitride foams(MEANFs),as innovative materials for electromagnetic wave(EMW)absorption,have been successfully synthesized through the lattice expansion induced by nitrogen doping.This achievement notably overcomes the inherent constraints of conventional metal-based absorbers,including low resonance frequency,high conductivity,and elevated density,for the synergistic advantages provided by multimetallic alloys and foams.Microstructural analysis with comprehensive theoretical calculations provides in-depth insights into the formation mechanism,electronic structure,and magnetic moment of MEANFs.Furthermore,deliberate component design along with the foam structure proves to be an effective strategy for enhancing impedance matching and absorption.The results show that the MEANFs exhibit a minimum reflection loss(RL_(min))value of-60.32 dB and a maximum effective absorption bandwidth(EAB_(max))of 5.28 GHz at 1.69 mm.This augmentation of energy dissipation in EMW is predominantly attributed to factors such as porous structure,interfacial polarization,defect-induced polarization,and magnetic resonance.This study demonstrates a facile and efficient approach for synthesizing single-phase medium-entropy alloys,emphasizing their potential as materials for electromagnetic wave absorption due to their adjustable magnetic-dielectric properties.
基金funded by the Science and Technology Vice President Project in Changping District,Beijing(Project Name:Research on multi-scale optimization and intelligent control technology of integrated energy systemProject number:202302007013).
文摘The critical components of gas turbines suffer from prolonged exposure to factors such as thermal oxidation,mechanical wear,and airflow disturbances during prolonged operation.These conditions can lead to a series of issues,including mechanical faults,air path malfunctions,and combustion irregularities.Traditional modelbased approaches face inherent limitations due to their inability to handle nonlinear problems,natural factors,measurement uncertainties,fault coupling,and implementation challenges.The development of artificial intelligence algorithms has provided an effective solution to these issues,sparking extensive research into data-driven fault diagnosis methodologies.The review mechanism involved searching IEEE Xplore,ScienceDirect,and Web of Science for peerreviewed articles published between 2019 and 2025,focusing on multi-fault diagnosis techniques.A total of 220 papers were identified,with 123 meeting the inclusion criteria.This paper provides a comprehensive review of diagnostic methodologies,detailing their operational principles and distinctive features.It analyzes current research hotspots and challenges while forecasting future trends.The study systematically evaluates the strengths and limitations of various fault diagnosis techniques,revealing their practical applicability and constraints through comparative analysis.Furthermore,this paper looks forward to the future development direction of this field and provides a valuable reference for the optimization and development of gas turbine fault diagnosis technology in the future.
基金the State Key Laboratory for Manufacturing System Engineering at Xi'an Jiaotong University. China.
文摘Deadlock avoidance problems are investigated for automated manufacturing systems with flexible routings. Based on the Petri net models of the systems, this paper proposes, for the first time, the concept of perfect maximal resourcetransition circuits and their saturated states. The concept facilitates the development of system liveness characterization and deadlock avoidance Petri net supervisors. Deadlock is characterized as some perfect maximal resource-transition circuits reaching their saturated states. For a large class of manufacturing systems, which do not contain center resources, the optimal deadlock avoidance Petri net supervisors are presented. For a general manufacturing system, a method is proposed for reducing the system Petri net model so that the reduced model does not contain center resources and, hence, has optimal deadlock avoidance Petri net supervisor. The controlled reduced Petri net model can then be used as the liveness supervisor of the system.
基金supported by the National Natural Science Foundation of China(Grant Nos.61573156,61273126,61503142,61272382,and 61573154)the Fundamental Research Funds for the Central Universities(Grant No.x2zd D2153620)
文摘This paper investigates the stochastic bounded consensus of leader-following second-order multi-agent systems in a noisy environment. It is assumed that each agent received the information of its neighbors corrupted by noises and time delays. Based on the graph theory, stochastic tools, and the Lyapunov function method, we derive the sufficient conditions under which the systems would reach stochastic bounded consensus in mean square with the protocol we designed. Finally, a numerical simulation is illustrated to check the effectiveness of the proposed algorithms.
基金supported by the National Natural Science Foundation of China (60874114)the Fundamental Research Funds for the Central Universities, South China University of Technology (SCUT)(2009ZM0140)
文摘The problem of delay-dependent exponential stability is investigated for impulsive stochastic systems with time-varying delay. Although the exponential stability of impulsive stochastic delay systems has been discussed by several authors, few works have been done on delay-dependent exponential stability of impulsive stochastic delay systems. Firstly, the Lyapunov-Krasovskii functional method combing the free-weighting matrix approach is applied to investigate this problem. Some delay-dependent mean square exponential stability criteria are derived in terms of linear matrix inequalities. In particular, the estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive effects. The obtained results show that the system will stable if the impulses＇ frequency and amplitude are suitably related to the increase or decrease of the continuous flows, and impulses may be used as controllers to stabilize the underlying stochastic system. Numerical examples are given to show the effectiveness of the results.
基金the financial support of the National Key Research and Development Plan(2021YFB3302501)the financial support of the National Natural Science Foundation of China(12102077)。
文摘Safe and efficient sortie scheduling on the confined flight deck is crucial for maintaining high combat effectiveness of the aircraft carrier.The primary difficulty exactly lies in the spatiotemporal coordination,i.e.,allocation of limited supporting resources and collision-avoidance between heterogeneous dispatch entities.In this paper,the problem is investigated in the perspective of hybrid flow-shop scheduling problem by synthesizing the precedence,space and resource constraints.Specifically,eight processing procedures are abstracted,where tractors,preparing spots,catapults,and launching are virtualized as machines.By analyzing the constraints in sortie scheduling,a mixed-integer planning model is constructed.In particular,the constraint on preparing spot occupancy is improved to further enhance the sortie efficiency.The basic trajectory library for each dispatch entity is generated and a delayed strategy is integrated to address the collision-avoidance issue.To efficiently solve the formulated HFSP,which is essentially a combinatorial problem with tightly coupled constraints,a chaos-initialized genetic algorithm is developed.The solution framework is validated by the simulation environment referring to the Fort-class carrier,exhibiting higher sortie efficiency when compared to existing strategies.And animation of the simulation results is available at www.bilibili.com/video/BV14t421A7Tt/.The study presents a promising supporting technique for autonomous flight deck operation in the foreseeable future,and can be easily extended to other supporting scenarios,e.g.,ammunition delivery and aircraft maintenance.
基金supported by the AMS Funding Project(No.ZZB2023C7010).
文摘Glial fibrillary acidic protein(GFAP)is one of the discriminative biomarkers for diagnosing traumatic brain injury(TBI),and accurate determination of GFAP is clinically significant.In this study,a novel fluorescence immunoassay system was designed.We encapsulated carbon dots with a high fluorescence quantum yield(QY=92.5%)inside silicon nanocapsules to serve as fluorescent markers.These markers were then integrated with the streptavidin(SA)-biotin biomagnification system and immunomagnetic separation technology for the sensitive detection of GFAP.Based on the signal cascade amplification effect of the silicon nanocapsules and SA-biotin,the fluorescence signal of the SA-biotin-modified immunofluorescence nanocapsules increased 3.6-fold compared to the carbon dot-based immunoprobe.The fluorescence immunoassay system was constructed for GFAP using SA-biotin-modified immunocapsules as the sensing probe and immunomagnetic nanoparticles as the immunorecognition probe.The fluorescence immunoassay system can specifically and ultra-sensitively quantify GFAP in blood samples,with a detection range of 10 pg/mL–10 ng/mL and detection limits of 3.2 pg/mL(serum)and 3.6 pg/mL(plasma).Moreover,the fluorescence immunoassay system exhibited prominent recoveries of 99.4%–100.4%(phosphate buffered saline),96%–102.6%(serum),and 93.2%–110.2%(plasma),with favorable specificity and excellent stabilization.The novel fluorescence immunoassay system provides a new approach to the clinical analysis of GFAP and may serve as a potential tool for screening and diagnosing TBI.
基金supported in part by the Beijing Natural Science Foundation(No.4254072).
文摘In wireless communication scenarios,especially in low-bandwidth or noisy transmission conditions,image data is often degraded by interference during acquisition or transmission.To address this,we proposed Wasserstein frequency generative adversarial networks(WF-GAN),a frequency-aware denoising model based on wavelet transformation.By decomposing images into four frequency sub-bands,the model separates low-frequency contour information from high-frequency texture details.Contour guidance is applied to preserve structural integrity,while adversarial training enhances texture fidelity in the high-frequency bands.A joint loss function,incorporating frequency-domain loss and perceptual loss,is designed to reduce detail degradation during denoising.Experiments on public image datasets,with Gaussian noise applied to simulate wireless communication interference,demonstrate that WF-GAN consistently outperforms both traditional and deep learning-based denoising methods in terms of visual quality and quantitative metrics.These results highlight its potential for robust image processing in wireless communication systems.
基金supported by the National Natural Science Foundation of China(32172211,32572557)the Key Science Research Projects of Higher Education Institutions in Henan Province(21A530006)+3 种基金the Key Research and Development and Promotion Projects of Henan Province(232102310293)the Henan Provincial Natural Science Foundation General Program(252300421403)the Zhongyuan Sci-Tech Innovation Leading Talents(254200510040)the Innovative Research Team(in Science and Technology)in University of Henan Province(26IRTSTHN030).
文摘Microbial food is an important direction of sustainable food development in the future.Microorganisms such as lactic acid bacteria(LAB)are important sources of natural radioprotectors.Moderate environmental stress can induce stress response and improve biological activity of LAB.In the previous study,Lactococcus lactis subsp.lactis IL1403(L.lactis IL1403)cell-free extract induced by ionizing radiation(IR)of 500 Gy(IR-CFE)presented the stronger radioprotective effect than untreated cell-free extract in mice.To explore the radioprotective active substances of IR-CFE,the key protein was screened by proteomics and its radioprotective effect in vivo was further evaluated.The Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment showed that two-component systems(TCS)were enhanced to adapt the IR induction.Meanwhile,the protein LlrG belonged to TCS was screened by the protein-protein interaction.Furthermore,the recombinant protein LlrG(rLlrG)could markedly alleviate the ^(60)Coγ-induced damage to the hematopoietic system,oxidative stress and inflammation in mice,thereby exerting its radioprotective function.These results suggested LlrG protein not only played an important role in the adaptation of L.lactis IL1403 to IR environment,but also exerted a good radioprotective effect,which could be applied in the development of protein-based radioprotectors.
基金supported by the National Natural Science Foundation of China(Grant No.52071294)the National Key Research and Development Program(Grant No.2022YFE0109800)the Natural Science Foundation of Zhejiang Province(Grant No.LY20E020015).
文摘Bioinspired nacre-like structured high-density soft magnetic composites(SMCs)have been successfully constructed using flaky-Fe_(73.8)Si_(13.5)B_(8.7)Cu_(1)Nb_(3) powders in the supercooled liquid region(SCLR).These densely arranged particles with a consistent planar orientation significantly enhance the soft magnetic properties of SMCs,including high permeability and low magnetic losses.The internal structures of the composites and microstructure evolution of the flaky nanocrystalline particles during the hot-pressing process have been thoroughly studied.Moreover,systematic investigations into the effects of coatings and particle sizes on the maximum permeability and magnetic losses of the composites are conducted.The SMC prepared using the coated particles with a size of 0-100μm exhibits a high maximum perme-ability of 2170(at 1000 Hz)and low magnetic loss of 41.61 W kg^(-1)(at 1000 Hz and 1.0 T).The losses and permeability analysis reveal that the superior performance of these soft magnetic materials is attributed to their laminated structure,insulation coating,and the reduced planar demagnetizing factor.Compared to the traditional silicon steel,this novel SMCs exhibits high magnetic permeability and reduced magnetic losses at frequencies above 1000 Hz,which possess immense application potential within high-frequency electric machines.
基金the National Key Research and Development Program of China(No.2022ZD0210500)the National Natural Science Foundation of China(Nos.61972067,U21A20491,and 62103437)the Dalian Outstanding Youth Science Foundation(No.2022RJ01)。
文摘Deep neural networks,especially face recognition models,have been shown to be vulnerable to adversarial examples.However,existing attack methods for face recognition systems either cannot attack black-box models,are not universal,have cumbersome deployment processes,or lack camouflage and are easily detected by the human eye.In this paper,we propose an adversarial pattern generation method for face recognition and achieve universal black-box attacks by pasting the pattern on the frame of goggles.To achieve visual camouflage,we use a generative adversarial network(GAN).The scale of the generative network of GAN is increased to balance the performance conflict between concealment and adversarial behavior,the perceptual loss function based on VGG19 is used to constrain the color style and enhance GAN’s learning ability,and the fine-grained meta-learning adversarial attack strategy is used to carry out black-box attacks.Sufficient visualization results demonstrate that compared with existing methods,the proposed method can generate samples with camouflage and adversarial characteristics.Meanwhile,extensive quantitative experiments show that the generated samples have a high attack success rate against black-box models.
基金supported in part by the Ship Preliminary Research Project (No.3020401020102)。
文摘This study addresses the issue of spray icing on the air intake grilles of ship power systems in cold maritime environments.Through numerical simulation methods,the influence of environmental parameters on icing characteristics is revealed,and an energy-efficient zoned electric heating anti-icing strategy is proposed.A threedimensional grille model is constructed to systematically analyze the effects of environmental temperature(from−20℃to−4℃),droplet diameter(from 50μm to 500μm),and liquid water content(from 0.5 g/m³to 8 g/m³)on icing rates and blockage of the flow channel.The results indicate that low temperature and high liquid water content significantly exacerbate icing.Under the condition of an environmental temperature of−20℃,droplet diameter of 500μm,and liquid water content of 8 g/m³,the flow channel blockage ratio reaches 30.95%within 10 min.Additionally,as droplet diameter increases,the droplet impingement and icing regions become more concentrated toward the leading edge of blades.To mitigate grille icing in cold environments,an electric heating film configuration is employed for thermal protection.Optimization of the heating strategy reveals that the zoned heating approach,compared to the initial uniform heating scheme,effectively homogenizes surface temperature distribution while reducing total power consumption by 37.47%.This study validates the engineering applicability of the zoned electric heating anti/de-icing strategy,providing theoretical and technical support for the design of anti-icing systems in ship power systems operating in cold maritime regions.
基金financially supported by the National Natural Science Foundation of China(No.52471212)the National Key Research and Development Program(No.2022YFE0109800).
文摘Despite significant progress in the structure and properties of porous absorbing materials,major challenges remain due to complex preparation technology,high production costs,and poor corrosion resistance.In this study,nanowires were used as the substrate,liquid nitrogen controls ice crystal growth orientation,and ammonia gas facilitates the generation of magnetic substances.The resulting pure magnetic porous foam(PMF)material exhibits enhanced performance in absorbing electromagnetic waves(EMWs)and improved corrosion resistance.The PMF's microstructure was analyzed for its dielectric and magnetic loss characteristics.The PMF combines a porous framework,nanoscale architecture,and exclusive magnetic components to create a lightweight foam absorbent material with enhanced magnetic dissipation capabilities.Among them,the Fe_(4)N PMF demonstrates an impressive minimum reflection loss(RLmin)value of−66.8 dB at a thickness of 1.09 mm,exhibits an effective absorption bandwidth of 4.00 GHz,and shows exceptional corrosion resistance with a self-corrosion potential of−0.65 V.Moreover,the effectiveness of the Fe_(4)N PMF in absorbing intelligent EMWs has been validated through radar cross-section(RCS)simulations.In summary,this study has developed electromagnetic wave-absorbing materials with slim profiles,lightweight properties,strong absorption capabilities,and excellent corrosion resistance.These characteristics make them highly promising for microwave absorption applications.
基金The contract No.PRJ-395/DPKS/2022 or 2383/PKS/ITS/2022 on 14 November 2022.
文摘The total replacement of old fossil fuels poses obstacles,making the production of efficient biogasoline vital.Despite its potential as an environmentally friendly fossil fuel substitute,the life cycle assessment(LCA)of palm oil-derived biogasoline remains underexplored.This study investigated the production of biogasoline fromcrude palm oil(CPO)based biorefinery using catalytic cracking over mesoporousγ-Al_(2)O_(3) catalyst and LCA analysis.High selectivity of converting CPO into biogasoline was achieved by optimizing catalytic cracking parameters,including catalyst dose,temperature,and contact time.γ-Al_(2)O_(3) and CPO were characterized by several methods to study the physical and chemical properties.The physical properties of biogasoline,such as density,calorific value,viscosity,and flash point,were investigated.An overall yield of 60.11%was achieved after catalytic cracking produced several C5-C11 short-chain hydrocarbons.Additionally,this research proposes innovative emission reduction strategies,including waste-to-biogasoline conversion and the use of biodegradable feedstocks that enhance the sustainability of biogasoline production.LCA ofγ-Al_(2)O_(3)’s energy and environmental implications reveals minor effects on global warming(0.0068%)and freshwater ecotoxicity(0.187%).LCAs show a 0.085%impact in the energy sector.This focus on both ecological impacts and practical mitigation strategies deepens the understanding of biogasoline production.
基金supported by the National Natural Science Foundation of China with Grants 62301076 and 62321001。
文摘Physical layer security methods based on joint relay and jammer selection(JRJS)have been widely investigated in the study of secure wireless communications.Different from current works on JRJS schemes,which assumed that the global channel state information(CSI)of the eavesdroppers(Eves)was known beforehand,then the optimal relaying and jamming relays were determined.More importantly,the time complexity of selecting optimal jamming relay is O(N^(2)),where N is the maximum number of relays/Eves.In this paper,for the scenario where the source wants to exchange the message with the destination,via relaying scheme due to longer communication distance and limited transmission power,in the presence of multiple Eves,with the assumption of Eves'perfect CSI and average CSI,we propose two kinds of JRJS methods.In particular,the time complexity of finding the optimal jammer can be reduced to O(N).Furthermore,we present a novel JRJS scheme for no CSI of Eves by minimizing the difference between expected signal and interfering signal at the destination.Finally,simulations show that the designed methods are more effective than JRJS and other existing strategies in terms of security performance.
基金supported by Shenzhen 2022 Key Project for Technological Research(Grant Number JSGG20220831110803006)key technology research and demonstration project of 10 MW deep-sea floating offshore wind turbine(DTGD-2023-10174)key technology research task of floating offshore combined wind and wave power generation and MIIT program for Floating VAWT.
文摘As a vessel navigates at high speeds in waves,considerable pitching motion can result in the discomfort of passengers.In this study is proposed a ride control system consisting of dual T-foils to generate a larger righting moment than a common single T-foil system.One T-foil is mounted at the bow,and the other at the stern.Accordingly,different control strategies for dual T-foils were proposed To verify the stratigies,a model experiment was conducted in the Towing Tank,Dalian Unievrsity of Technology.The optimal control signal was determined by comparing the pitch responses,heave responses,bow accelerations,and stern accelerations of a vessel in regular waves.In addition,the control strategy for the best motion-reduction effect was investigated.The optimized dual T-foil system provides a 34%reduction in pitch motion.
基金supported by the National Natural Science Foundation of China(61803015).
文摘In order to enhance the dynamic control precision of inertial stabilization platform(ISP),a disturbance sliding mode observer(DSMO)is proposed in this paper suppressing disturbance torques inherent within the system.The control accuracy of ISP is fundamentally circumscribed by various disturbance torques in rotating shaft.Therefore,a dynamic model of ISP incorporating composite perturbations is established with regard to the stabilization of axis in the inertial reference frame.Subsequently,an online estimator for control loop uncertainties based on the sliding mode control algorithm is designed to estimate the aggregate disturbances of various parameters uncertainties and other unmodeled disturbances that cannot be accurately calibrated.Finally,the proposed DSMO is integrated into a classical proportional-integral-derivative(PID)control scheme,utilizing feedforward approach to compensate the composite disturbance in the control loop online.The effectiveness of the proposed disturbance observer is validated through simulation and hardware experimentation,demonstrating a significant improvement in the dynamic control performance and robustness of the classical PID controller extensively utilized in the field of engineering.
基金the financial support of the National Natural Science Foundation of China(12102077,12161076)the Natural Science and Technology Program of Liaoning Province(2023-BS-061).
文摘Recovery is a crucial supporting process for carrier aircraft,where a reasonable landing scheduling is expected to guide the fleet landing safely and quickly.Currently,there is little research on this topic,and most of it neglects potential influence factors,leaving the corresponding supporting efficiency questionable.In this paper,we study the landing scheduling problem for carrier aircraft considering the effects of bolting and aerial refueling.Based on the analysis of recovery mode involving the above factors,two types of primary constraints(i.e.,fuel constraint and wake interval constraint)are first described.Then,taking the landing sequencing as decision variables,a combinatorial optimization model with a compound objective function is formulated.Aiming at an efficient solution,an improved firefly algorithm is designed by integrating multiple evolutionary operators.In addition,a dynamic replanning mechanism is introduced to deal with special situations(i.e.,the occurrence of bolting and fuel shortage),where the high efficiency of the designed algorithm facilitates the online scheduling adjustment within seconds.Finally,numerical simulations with sufficient and insufficient fuel cases are both carried out,highlighting the necessity to consider bolting and aerial refueling during the planning procedure.Simulation results reveal that a higher bolting probability,as well as extra aerial refueling operations caused by fuel shortage,will lead to longer recovery complete time.Meanwhile,due to the strong optimum-seeking capability and solution efficiency of the improved algorithm,adaptive scheduling can be generated within milliseconds to deal with special situations,significantly improving the safety and efficiency of the recovery process.An animation is accessible at bilibili.com/video/BV1QprKY2EwD.
基金supported in part by the National Natural Science Foundation of China(62003265)2023 Suzhou Innovation and Entrepreneurship Leading Talents Program (Young Innovative Leading Talents)(ZXL2023178)+2 种基金Natural Science Basic Research Program of Shaanxi (2025JC-YBMS-656)Tongxiang Institute of Artificial General Intelligence (TAGI2-A-2024-0006)the Deanship of Scientific Research (DSR) at King Abdulaziz University,Jeddah,Saudi Arabia (GPIP:908-135-2024)
文摘With the increasing concerns about energy consumption and environmental protection, minimizing energy consumption while ensuring desired productivity becomes more and more important in flexible assembly systems(FASs) design and operation. However, because of the complexity of deadlock-prone FASs, only a few researchers have addressed their scheduling problems. Besides, no existing literature in the field of scheduling of deadlock-prone FASs takes energy consumption minimization as the optimization criterion to our best knowledge. This paper presents an A^(*)-based hybrid heuristic search algorithm to minimize the total energy consumption of FASs with tool change processes. Based on a developed Petri net(PN) model, two energy functions are proposed to calculate the energy consumption of FASs. To achieve better performance, six new heuristic functions are designed to guide the search process by considering the features of FASs. Besides, two selection functions are proposed to evaluate the prospects of vertexes and choose the promising ones.Moreover, a dynamic window is applied in the algorithm to limit the search space, and a deadlock prevention policy is used to ensure feasible schedules. Experimental results show that the proposed algorithm can effectively find feasible schedules for FASs,and a well-designed heuristic function is likely to obtain schedules to meet industrial application requirements.
