Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads ...Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads and time-varying material properties,the relationship between wear state and Remaining Useful Life(RUL)is nonlinear.Consequently,accurately modeling this wear remains a significant challenge,as existing research often neglects the coupled effects of material properties,stress conditions,and dynamic lubrication parameters.To address this issue,this study proposes a novel framework integrating physical mechanisms with stochastic processes to enhance wear degradation modelling and RUL prediction.First,a Physics-of-Failure(PoF)model is developed based on Archard's wear theory,which characterizes tribological behavior at the contact interface and accounts for the effects of lubrication and load conditions.Next,a Gamma process is introduced to model the degradation trajectory,with physical parameters guiding the specification of the time-scale function.A Bayesian expectation–maximization algorithm is employed to estimate and update the model parameters.Finally,a numerical simulation and case study on spool valves are conducted to demonstrate the effectiveness of the proposed model.The cross-validation results confirmed that the introduction of random effects effectively reduces the impact of uncertainty on physics-informed modeling.This study offers a systematic solution to RUL prediction for hydraulic systems.展开更多
In this paper,the bipartite consensus problem is studied for a class of uncertain high-order nonlinear multi-agent systems.A signed digraph is presented to describe the collaborative and competitive interactions among...In this paper,the bipartite consensus problem is studied for a class of uncertain high-order nonlinear multi-agent systems.A signed digraph is presented to describe the collaborative and competitive interactions among agents.For each agent with lower triangular structure,a time-varying gain compensator is first designed by relative output information of neighboring agents.Subsequently,a distributed controller with dynamic event-triggered mechanism is proposed to drive the bipartite consensus error to zero.It is worth noting that an internal dynamic variable is introduced in triggering function,which plays an essential role in excluding the Zeno behavior and reducing energy consumption.Furthermore,the dynamic event-triggered control protocol is developed for upper triangular multi-agent systems to realize the bipartite consensus without Zeno behavior.Finally,simulation examples are provided to illustrate the effectiveness of the presented results.展开更多
Minimal hepatic encephalopathy(MHE)is a critical neurocognitive complication of decompensated liver cirrhosis and portosystemic shunting,which results in a wide range of cognitive deficits including impairments in wor...Minimal hepatic encephalopathy(MHE)is a critical neurocognitive complication of decompensated liver cirrhosis and portosystemic shunting,which results in a wide range of cognitive deficits including impairments in working attention,psychomotor speed,and executive function.Current guidelines have recommended paper-and-pencil psychometric tests for the diagnosis of MHE.Most high-risk cirrhotic patients are required to be examined;however,paperand-pencil psychometric tests are neither convenient nor rapid to perform in the clinic.Recently,novel computerized psychometric tests,including the inhibitory control test,EncephalApp Stroop App,and critical flicker frequency,have been proven to be rapid,effective,and convenient methods for screening MHE in clinical practice and for identifying high-risk cirrhotic patients for further validation using rigid neuropsychometric examinations.However,diagnostic accuracy of these tests is influenced by educational background,age,and cultural differences.This review summarizes clinical evidence of the application of novel computerized psychometric tests for screening MHE.展开更多
The problem of secure consensus for multi-agent systems(MASs)is tackled in this study.The self-triggering strategy is designed to enable each healthy agent to estimate its next triggering step at the current triggerin...The problem of secure consensus for multi-agent systems(MASs)is tackled in this study.The self-triggering strategy is designed to enable each healthy agent to estimate its next triggering step at the current triggering step.Thus,each healthy agent only needs to sense and broadcast at its triggering steps,and to monitor the latest broadcast states of their neighbors at their triggering steps.The frequent monitoring is thereby mitigated.Subsequently,a self-triggering secure consensus algorithm is developed to guarantee that the state variables of healthy agents reach consensus despite the influence of faulty agents in the network.The convergence analysis of the proposed method is conducted with graph tools and Lyapunov theory.Numerical examples are given to illustrate the superior performance of the proposed self-triggering secure consensus algorithm compared with the existing methods based on the static and dynamic event-triggering mechanisms.展开更多
Lipogenesis is often highly upregulated in breast cancer brain metastases to adapt to intracranial low lipid microenvironments.Lipase inhibitors hold therapeutic potential but their intra-tumoral distribution is often...Lipogenesis is often highly upregulated in breast cancer brain metastases to adapt to intracranial low lipid microenvironments.Lipase inhibitors hold therapeutic potential but their intra-tumoral distribution is often blocked by the blood-tumor barrier(BTB).BTB activates its Wnt signaling to maintain barrier properties,e.g.,Mfsd2a-mediated BTB low transcytosis.Here,we reported VCAM-1-targeting nano-wogonin(W@V-NPs)as an adjuvant of nano-orlistat(O@V-NPs)to intensify drug delivery and inhibit lipogenesis of brain metastases.W@V-NPs were proven to be able to inactivate BTB Wnt signaling,downregulate BTB Mfsd2a,accelerate BTB vesicular transport,and enhance tumor accumulation of O@V-NPs.With the ability to specifically kill cancer cells in a lipid-deprived environment with IC_(50) at 48 ng/mL,W@V-NPs plus O@V-NPs inhibited the progression of brain metastases with prolonged survival of model mice.The combination did not induce brain edema,cognitive impairment,and systemic toxicity in healthy mice.Targeting Wnt signaling could safely modulate the BTB to improve drug delivery and metabolic therapy against brain metastases.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.U2233212,52375036,62303030 and 62403028)the Postdoctoral Fellowship Program of CPSF,China(Nos.GZC20242158 and GZC20233377)+1 种基金Open Fund of State Key Laboratory of Mechanical Transmission for Advanced Equipment,China(No.SKLMT-MSKFKT-202421)the Fundamental Research Funds for the Central Universities,China。
文摘Internal leakage caused by wear in hydraulic spool valves represents a critical failure mode that threatens the performance of aircraft hydraulic systems and compromises flight safety.Due to complex operational loads and time-varying material properties,the relationship between wear state and Remaining Useful Life(RUL)is nonlinear.Consequently,accurately modeling this wear remains a significant challenge,as existing research often neglects the coupled effects of material properties,stress conditions,and dynamic lubrication parameters.To address this issue,this study proposes a novel framework integrating physical mechanisms with stochastic processes to enhance wear degradation modelling and RUL prediction.First,a Physics-of-Failure(PoF)model is developed based on Archard's wear theory,which characterizes tribological behavior at the contact interface and accounts for the effects of lubrication and load conditions.Next,a Gamma process is introduced to model the degradation trajectory,with physical parameters guiding the specification of the time-scale function.A Bayesian expectation–maximization algorithm is employed to estimate and update the model parameters.Finally,a numerical simulation and case study on spool valves are conducted to demonstrate the effectiveness of the proposed model.The cross-validation results confirmed that the introduction of random effects effectively reduces the impact of uncertainty on physics-informed modeling.This study offers a systematic solution to RUL prediction for hydraulic systems.
基金This work was supported by the National Natural Science Foundation of China(Nos.61973189,62073190)the Research Fund for the Taishan Scholar Project of Shandong Province of China(No.ts20190905)the Natural Science Foundation of Shandong Province of China(No.ZR2020ZD25).
文摘In this paper,the bipartite consensus problem is studied for a class of uncertain high-order nonlinear multi-agent systems.A signed digraph is presented to describe the collaborative and competitive interactions among agents.For each agent with lower triangular structure,a time-varying gain compensator is first designed by relative output information of neighboring agents.Subsequently,a distributed controller with dynamic event-triggered mechanism is proposed to drive the bipartite consensus error to zero.It is worth noting that an internal dynamic variable is introduced in triggering function,which plays an essential role in excluding the Zeno behavior and reducing energy consumption.Furthermore,the dynamic event-triggered control protocol is developed for upper triangular multi-agent systems to realize the bipartite consensus without Zeno behavior.Finally,simulation examples are provided to illustrate the effectiveness of the presented results.
文摘Minimal hepatic encephalopathy(MHE)is a critical neurocognitive complication of decompensated liver cirrhosis and portosystemic shunting,which results in a wide range of cognitive deficits including impairments in working attention,psychomotor speed,and executive function.Current guidelines have recommended paper-and-pencil psychometric tests for the diagnosis of MHE.Most high-risk cirrhotic patients are required to be examined;however,paperand-pencil psychometric tests are neither convenient nor rapid to perform in the clinic.Recently,novel computerized psychometric tests,including the inhibitory control test,EncephalApp Stroop App,and critical flicker frequency,have been proven to be rapid,effective,and convenient methods for screening MHE in clinical practice and for identifying high-risk cirrhotic patients for further validation using rigid neuropsychometric examinations.However,diagnostic accuracy of these tests is influenced by educational background,age,and cultural differences.This review summarizes clinical evidence of the application of novel computerized psychometric tests for screening MHE.
基金supported by the National Natural Science Foundation of China(Grant Nos.62173147,62303030,62403028 and U2233212)Beijing Municipal Natural Science Foundation(Grant No.L221008)+1 种基金Open Fund of Science and Technology on Thermal Energy and Power Laboratory(Grant No.TPL2022C02)Postdoctoral Fellowship Program of CPSF(Grant No.GZC20233377)
文摘The problem of secure consensus for multi-agent systems(MASs)is tackled in this study.The self-triggering strategy is designed to enable each healthy agent to estimate its next triggering step at the current triggering step.Thus,each healthy agent only needs to sense and broadcast at its triggering steps,and to monitor the latest broadcast states of their neighbors at their triggering steps.The frequent monitoring is thereby mitigated.Subsequently,a self-triggering secure consensus algorithm is developed to guarantee that the state variables of healthy agents reach consensus despite the influence of faulty agents in the network.The convergence analysis of the proposed method is conducted with graph tools and Lyapunov theory.Numerical examples are given to illustrate the superior performance of the proposed self-triggering secure consensus algorithm compared with the existing methods based on the static and dynamic event-triggering mechanisms.
基金supported by the National Natural Science Foundation of China(32171381 and 81973254)the National Innovation of Science and Technology-2030(Program of Brain Science and Brain-Inspired Intelligence Technology)grant(2021ZD0204004,China)+1 种基金Jiangsu Key Laboratory of Neuropsychiatric Diseases Research Major Program(No.ZZ2101,China)the Priority Academic Program Development of the Jiangsu Higher Education Institutes(PAPD),Suzhou International Joint Laboratory for Diagnosis and Treatment of Brain Diseases,and the Suzhou Science and Technology Development Project(No.SJC2022021,China).
文摘Lipogenesis is often highly upregulated in breast cancer brain metastases to adapt to intracranial low lipid microenvironments.Lipase inhibitors hold therapeutic potential but their intra-tumoral distribution is often blocked by the blood-tumor barrier(BTB).BTB activates its Wnt signaling to maintain barrier properties,e.g.,Mfsd2a-mediated BTB low transcytosis.Here,we reported VCAM-1-targeting nano-wogonin(W@V-NPs)as an adjuvant of nano-orlistat(O@V-NPs)to intensify drug delivery and inhibit lipogenesis of brain metastases.W@V-NPs were proven to be able to inactivate BTB Wnt signaling,downregulate BTB Mfsd2a,accelerate BTB vesicular transport,and enhance tumor accumulation of O@V-NPs.With the ability to specifically kill cancer cells in a lipid-deprived environment with IC_(50) at 48 ng/mL,W@V-NPs plus O@V-NPs inhibited the progression of brain metastases with prolonged survival of model mice.The combination did not induce brain edema,cognitive impairment,and systemic toxicity in healthy mice.Targeting Wnt signaling could safely modulate the BTB to improve drug delivery and metabolic therapy against brain metastases.
