The aviation oxygen mask,which has a small volume of less than 1L and strong air tightness,imposes extremely high requirements on control performance of the oxygen regulator.Based on analyses of the operation principl...The aviation oxygen mask,which has a small volume of less than 1L and strong air tightness,imposes extremely high requirements on control performance of the oxygen regulator.Based on analyses of the operation principle of oxygen supply system,the dynamic model is established through the combination of mechanism analysis and experimental data.Considering that the traditional fixed-parameter controllers are difficult to meet the control requirements with changes in pulmonary ventilation,this paper presents an online feedback controller based on neural network compensation(NNC),with connection weights that can be updated without pre-training.Then mathematical simulations at different respiratory parameters,such as respiratory rate,are performed to verify the superior lower inspiratory resistance of controller with NNC.In terms of hardware,an embedded AI control platform is to complete the experimental verification.Furthermore,the work may have downward compatibility to achieve stable oxygen supply in civil fields,such as medical ventilators,high-altitude expeditions.展开更多
The high-purity distillation column system is strongly nonlinear and coupled,which makes it difficult to control.Active disturbance rejection control(ADRC)has been widely used in distillation systems,but it has limita...The high-purity distillation column system is strongly nonlinear and coupled,which makes it difficult to control.Active disturbance rejection control(ADRC)has been widely used in distillation systems,but it has limitations in controlling distillation systems with large time delays since ADRC employs ESO and feedback control law to estimate the total disturbance of the system without considering the large time delays.This paper designs a proportion integral-type active disturbance rejection generalized predictive control(PI-ADRGPC)algorithm to control the distillation column system with large time delay.It replaces the PD controller in ADRC with a proportion integral-type generalized predictive control(PI-GPC),thereby improving the performance of control systems with large time delays.Since the proposed controller has many parameters and is difficult to tune,this paper proposes to use the grey wolf optimization(GWO)to tune these parameters,whose structure can also be used by other intelligent optimization algorithms.The performance of GWO tuned PI-ADRGPC is compared with the control performance of GWO tuned ADRC method,multi-verse optimizer(MVO)tuned PI-ADRGPC and MVO tuned ADRC.The simulation results show that the proposed strategy can track reference well and has a good disturbance rejection performance.展开更多
Memristor chaotic systems have aroused great attention in recent years with their potentials expected in engineering applications.In this paper,a five-dimension(5D)double-memristor hyperchaotic system(DMHS)is modeled ...Memristor chaotic systems have aroused great attention in recent years with their potentials expected in engineering applications.In this paper,a five-dimension(5D)double-memristor hyperchaotic system(DMHS)is modeled by introducing two active magnetron memristor models into the Kolmogorov-type formula.The boundness condition of the proposed hyperchaotic system is proved.Coexisting bifurcation diagram and numerical verification explain the bistability.The rich dynamics of the system are demonstrated by the dynamic evolution map and the basin.The simulation results reveal the existence of transient hyperchaos and hidden extreme multistability in the presented DMHS.The NIST tests show that the generated signal sequence is highly random,which is feasible for encryption purposes.Furthermore,the system is implemented based on a FPGA experimental platform,which benefits the further applications of the proposed hyperchaos.展开更多
The utilization of thin plate systems based on acoustic vibration holds significant importance in micro-nano manipulation and the exploration of nonlinear science. This paper focuses on the analysis of an actual thin ...The utilization of thin plate systems based on acoustic vibration holds significant importance in micro-nano manipulation and the exploration of nonlinear science. This paper focuses on the analysis of an actual thin plate system driven by acoustic wave signals. By combining the mechanical analysis of thin plate microelements with the Bubnov–Galerkin integral method, the governing equation for the forced vibration of a square thin plate is derived. Notably,the reaction force of the thin plate vibration system is defined as f=α|w|, resembling Hooke’s law. The energy function and energy level curve of the system are also analyzed. Subsequently, the amplitude–frequency response function of the thin plate oscillator is solved using the harmonic balance method. Through numerical simulations, the amplitude–frequency curves are analyzed for different vibration modes under the influence of various parameters. Furthermore, the paper demonstrates the occurrence of conservative chaotic motions in the thin plate oscillator using theoretical and numerical methods. Dynamics maps illustrating the system’s states are presented to reveal the evolution laws of the system. By exploring the effects of force fields and system energy, the underlying mechanism of chaos is interpreted. Additionally, the phenomenon of chaos in the oscillator can be controlled through the method of velocity and displacement states feedback, which holds significance for engineering applications.展开更多
Fine particulate matter(PM_(2.5))is a significant risk factor for birth defects.As the first and most important organ to develop during embryogenesis,the heart’s potential susceptibility to PM_(2.5)has attracted grow...Fine particulate matter(PM_(2.5))is a significant risk factor for birth defects.As the first and most important organ to develop during embryogenesis,the heart’s potential susceptibility to PM_(2.5)has attracted growing concern.Despite several studies supporting the cardiac developmental toxicity of PM_(2.5),the diverse study types,models,and end points have prevented the integration of mechanisms.In this Review,we present an adverse outcome pathway framework to elucidate the association between PM_(2.5)-induced molecular initiating events and adverse cardiac developmental outcomes.Activation of the aryl hydrocarbon receptor(AhR)and excessive generation of reactive oxygen species(ROS)were considered as molecular initiating events.The excessive production of ROS induced oxidative stress,endoplasmic reticulum stress,DNA damage,and inflammation,resulting in apoptosis.The activation of the AhR inhibited the Wnt/β-catenin pathway and then suppressed cardiomyocyte differentiation.Impaired cardiomyocyte differentiation and persistent apoptosis resulted in abnormalities in the cardiac structure and function.All of the aforementioned events have been identified as key events(KEs).The culmination of these KEs ultimately led to the adverse outcome,an increased morbidity of congenital heart defects(CHDs).This work contributes to understanding the causes of CHDs and promotes the safety evaluation of PM_(2.5).展开更多
In this paper,an improved optimization approach,free search with double populations(FSDP)which is based on free search(FS)algorithm,is proposed.Comparing to FS algorithm,FSDP preserves the sub-optimal solutions and ad...In this paper,an improved optimization approach,free search with double populations(FSDP)which is based on free search(FS)algorithm,is proposed.Comparing to FS algorithm,FSDP preserves the sub-optimal solutions and adopts elitist strategy in the searching process,which effectively avoids falling into local optimum and improves the convergence speed and the search accuracy.Simulation results show that FSDP has a better comprehensive performance over FS,PSO and GA.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61973172,62003177,62003175 and 61973175).
文摘The aviation oxygen mask,which has a small volume of less than 1L and strong air tightness,imposes extremely high requirements on control performance of the oxygen regulator.Based on analyses of the operation principle of oxygen supply system,the dynamic model is established through the combination of mechanism analysis and experimental data.Considering that the traditional fixed-parameter controllers are difficult to meet the control requirements with changes in pulmonary ventilation,this paper presents an online feedback controller based on neural network compensation(NNC),with connection weights that can be updated without pre-training.Then mathematical simulations at different respiratory parameters,such as respiratory rate,are performed to verify the superior lower inspiratory resistance of controller with NNC.In terms of hardware,an embedded AI control platform is to complete the experimental verification.Furthermore,the work may have downward compatibility to achieve stable oxygen supply in civil fields,such as medical ventilators,high-altitude expeditions.
基金funded by the National Natural Science Foundation of China(61973175,62073177 and 61973172)South African National Research Foundation(132797)+2 种基金South African National Research Foundation Incentive(114911)Eskom Tertiary Education Support Programme Grant of South AfricaTianjin Research Innovation Project for Postgraduate Students(2021YJSB018,2020YJSB003)。
文摘The high-purity distillation column system is strongly nonlinear and coupled,which makes it difficult to control.Active disturbance rejection control(ADRC)has been widely used in distillation systems,but it has limitations in controlling distillation systems with large time delays since ADRC employs ESO and feedback control law to estimate the total disturbance of the system without considering the large time delays.This paper designs a proportion integral-type active disturbance rejection generalized predictive control(PI-ADRGPC)algorithm to control the distillation column system with large time delay.It replaces the PD controller in ADRC with a proportion integral-type generalized predictive control(PI-GPC),thereby improving the performance of control systems with large time delays.Since the proposed controller has many parameters and is difficult to tune,this paper proposes to use the grey wolf optimization(GWO)to tune these parameters,whose structure can also be used by other intelligent optimization algorithms.The performance of GWO tuned PI-ADRGPC is compared with the control performance of GWO tuned ADRC method,multi-verse optimizer(MVO)tuned PI-ADRGPC and MVO tuned ADRC.The simulation results show that the proposed strategy can track reference well and has a good disturbance rejection performance.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.62003177,61973172,61973175,and 62073177)the key Technologies Research and Tianjin Natural Science Foundation (Grant No.19JCZDJC32800)+1 种基金China Postdoctoral Science Foundation (Grant Nos.2020M670633 and 2020M670045)Academy of Finland (Grant No.315660)。
文摘Memristor chaotic systems have aroused great attention in recent years with their potentials expected in engineering applications.In this paper,a five-dimension(5D)double-memristor hyperchaotic system(DMHS)is modeled by introducing two active magnetron memristor models into the Kolmogorov-type formula.The boundness condition of the proposed hyperchaotic system is proved.Coexisting bifurcation diagram and numerical verification explain the bistability.The rich dynamics of the system are demonstrated by the dynamic evolution map and the basin.The simulation results reveal the existence of transient hyperchaos and hidden extreme multistability in the presented DMHS.The NIST tests show that the generated signal sequence is highly random,which is feasible for encryption purposes.Furthermore,the system is implemented based on a FPGA experimental platform,which benefits the further applications of the proposed hyperchaos.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61973172, 62003177, 62103204, 62003175, and 61973175)the Joint Fund of the Ministry of Education for Equipment Pre-research (Grant No. 8091B022133)General Terminal IC Interdisciplinary Science Center of Nankai University。
文摘The utilization of thin plate systems based on acoustic vibration holds significant importance in micro-nano manipulation and the exploration of nonlinear science. This paper focuses on the analysis of an actual thin plate system driven by acoustic wave signals. By combining the mechanical analysis of thin plate microelements with the Bubnov–Galerkin integral method, the governing equation for the forced vibration of a square thin plate is derived. Notably,the reaction force of the thin plate vibration system is defined as f=α|w|, resembling Hooke’s law. The energy function and energy level curve of the system are also analyzed. Subsequently, the amplitude–frequency response function of the thin plate oscillator is solved using the harmonic balance method. Through numerical simulations, the amplitude–frequency curves are analyzed for different vibration modes under the influence of various parameters. Furthermore, the paper demonstrates the occurrence of conservative chaotic motions in the thin plate oscillator using theoretical and numerical methods. Dynamics maps illustrating the system’s states are presented to reveal the evolution laws of the system. By exploring the effects of force fields and system energy, the underlying mechanism of chaos is interpreted. Additionally, the phenomenon of chaos in the oscillator can be controlled through the method of velocity and displacement states feedback, which holds significance for engineering applications.
基金supported by the National Key R&D Program of China(2022YFA0806900).
文摘Fine particulate matter(PM_(2.5))is a significant risk factor for birth defects.As the first and most important organ to develop during embryogenesis,the heart’s potential susceptibility to PM_(2.5)has attracted growing concern.Despite several studies supporting the cardiac developmental toxicity of PM_(2.5),the diverse study types,models,and end points have prevented the integration of mechanisms.In this Review,we present an adverse outcome pathway framework to elucidate the association between PM_(2.5)-induced molecular initiating events and adverse cardiac developmental outcomes.Activation of the aryl hydrocarbon receptor(AhR)and excessive generation of reactive oxygen species(ROS)were considered as molecular initiating events.The excessive production of ROS induced oxidative stress,endoplasmic reticulum stress,DNA damage,and inflammation,resulting in apoptosis.The activation of the AhR inhibited the Wnt/β-catenin pathway and then suppressed cardiomyocyte differentiation.Impaired cardiomyocyte differentiation and persistent apoptosis resulted in abnormalities in the cardiac structure and function.All of the aforementioned events have been identified as key events(KEs).The culmination of these KEs ultimately led to the adverse outcome,an increased morbidity of congenital heart defects(CHDs).This work contributes to understanding the causes of CHDs and promotes the safety evaluation of PM_(2.5).
基金supported in part by the Natural Science Foundation of China under Grants of 61174094,61273138the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant 20090031110029the Tianjin Nature Science Foundation under Grant 10JCZDJC15900.
文摘In this paper,an improved optimization approach,free search with double populations(FSDP)which is based on free search(FS)algorithm,is proposed.Comparing to FS algorithm,FSDP preserves the sub-optimal solutions and adopts elitist strategy in the searching process,which effectively avoids falling into local optimum and improves the convergence speed and the search accuracy.Simulation results show that FSDP has a better comprehensive performance over FS,PSO and GA.
