Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous sta...Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.展开更多
In this paper, we study the consensus problem for a class of linear multi-agent systems(MASs) with consideration of input saturation under the self-triggered mechanism. In the context of discrete-time systems, a self-...In this paper, we study the consensus problem for a class of linear multi-agent systems(MASs) with consideration of input saturation under the self-triggered mechanism. In the context of discrete-time systems, a self-triggered strategy is developed to determine the time interval between the adjacent triggers. The triggering condition is designed by using the current sampled consensus error. Furthermore, the consensus control protocol is designed by means of a state feedback approach. It is shown that the considered multi-agent systems can reach consensus with the presented algorithm. Some sufficient conditions are proposed in the form of linear matrix inequalities(LMIs) to show the positively invariant property of the domain of attraction(DOA). Moreover, some sufficient conditions of controller synthesis are provided to enlarge the volume of the DOA and obtain the control gain matrix. A numerical example is simulated to demonstrate the effectiveness of the theoretical analysis results.展开更多
A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Fie...A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Field distribution in the switch section is regulated by a metal field regulation ring and several gradient rings. In order to reduce the jitter further, a SFB/N2 mixture is chosen as the switching medium. The generalized standard deviation of the self-breakdown voltage and the deviation of the average value from the prediction is less than 4.4% and 13% respectively. Linearity of the self-breakdown voltage is better than 0.95. Triggered by a laser pulse of 35 mJ/3 ns, the delay is about 26 ns at a working voltage of 85±3% USB （Self-breakdown Voltage）. Maximum deviation of delay is less than =t=2.5 ns. Jitter is less than 1.5 ns. The delay and jitter decrease with the increase in the working ratio （the ratio of working voltage to USB）, pressure or voltage.展开更多
In the version of the article initially published,errors were identified in the figures,Figs.2Q and 6A,owing to the incorrect placement of images during the preparation and assembly of representative images.These revi...In the version of the article initially published,errors were identified in the figures,Figs.2Q and 6A,owing to the incorrect placement of images during the preparation and assembly of representative images.These revisions do not affect any results or conclusions in the article.The original data for these figures have been submitted to the Editorial Office,and access to this data can be obtained by contacting either the corresponding authors or the Editorial Office.展开更多
This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorith...This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.展开更多
The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the ...The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-展开更多
The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative f...The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.展开更多
Metallogels of an amphiphilic L-histidine derivative(LHC18)with various transition metal ions were investigated.It was found that while the amphiphile formed precipitates in aqueous solution when mixed with Cu^(2+),Zn...Metallogels of an amphiphilic L-histidine derivative(LHC18)with various transition metal ions were investigated.It was found that while the amphiphile formed precipitates in aqueous solution when mixed with Cu^(2+),Zn^(2+),Ni^(2+),it formed a hydrogel with Fe^(3+).Interestingly,upon cooling the transparent solution of LHC18 with Fe^(3+)to room temperature gently without any interruption,the gel was formed.Upon further resting at room temperature,the gel underwent shrinkage and 90% of ferric water was expelled from the gel.On the other hand,if the as-formed gel was shaken or shear forces were applied,the gel would collapse into sol.The collapsed sol will recover to become the gel within one minute upon resting and the process can be repeated many times.In addition,once the gel experiences the thixotropic process,it will not shrink anymore.So far,various metallogels have been reported,and we show the first example of a metallogel that shows dual shrinkage and self-healing properties.展开更多
Persistent luminescence has emerged as a robust platform for anti-counterfeiting applications due to its exceptional spatial-temporal decoding capability.Yet,conventional strategies often suffer from uniform emission ...Persistent luminescence has emerged as a robust platform for anti-counterfeiting applications due to its exceptional spatial-temporal decoding capability.Yet,conventional strategies often suffer from uniform emission patterns and predictable replication,compromising their security.Herein,we present“Snap-PLNPs”—near-infrared emitting CaS:Tm persistent luminescent nanoparticles engineered to undergo aqueous-triggered self-destruction via a hydrolysis mechanism.In contrast to traditional photophysical approaches,this chemically initiated degradation irreversibly terminates the luminescence,ensuring that security information can be decoded only once.Moreover,by incorporating an additional SiO_(2)shell,we introduce a programmable delay in the hydrolysis process,thereby modulating the duration of the emission and adding a temporal regulation layer.This dual control—combining instantaneous chemical deactivation with time-resolved modulation—establishes a dynamic hierarchical security encoding framework.When embedded into laser-engraved logos,these CaS:Tm@SiO_(2)hybrids enable a novel triple-layer anti-counterfeiting strategy that integrates spatial,temporal,and chemical dimensions.Our results underscore the potential of Snap-PLNPs as a next-generation platform for robust and adaptive security technologies.展开更多
Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6...Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.展开更多
网络控制系统通过通信网络连接传感器、控制器和执行器,实现远程监控和智能控制,具有突破地域限制的优势,但其开放性和网络依赖性也引入了诸多问题。首先,系统分析了网络控制系统中存在的信号量化误差、数据包丢失、网络时延、带宽占用...网络控制系统通过通信网络连接传感器、控制器和执行器,实现远程监控和智能控制,具有突破地域限制的优势,但其开放性和网络依赖性也引入了诸多问题。首先,系统分析了网络控制系统中存在的信号量化误差、数据包丢失、网络时延、带宽占用和网络安全威胁等问题;其次,在回顾网络控制系统研究成果的基础上,提出了新的控制策略,包括新型量化控制、随机丢包控制、时变时延的自触发控制、变采样周期智能调度控制、动态事件触发控制、DoS(denial of service)攻击的网络控制等;再次,归纳了相关的控制理论方法,包括随机系统法、预测控制法、时延估算与补偿、模糊反馈法、神经网络预测法;最后,提出了网络控制系统研究在未来面临的挑战。展开更多
基金supported by the National Natural Science Foundation of China(62403393,12202058,62103118)the China Postdoctoral Science Foundation(2021T140160,2023 T160051)the Natural Science Foundation of Chongqing(CSTB 2023NSCQ-MSX0152)
文摘Dear Editor,This letter deals with the stabilization problem of nonlinear stochastic systems via self-triggered impulsive control(STIC), where the timing of impulsive control actions is not dependent on continuous state monitoring. In contrast to the existing self-triggered control method, novel self-triggered mechanism(STM) is proposed by incorporating a waiting time for stabilizing impulses. This allows for direct prediction of the next impulsive instant.
基金supported by the National Natural Science Foundation of China(61921004,61520106009,U1713209,61973074)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘In this paper, we study the consensus problem for a class of linear multi-agent systems(MASs) with consideration of input saturation under the self-triggered mechanism. In the context of discrete-time systems, a self-triggered strategy is developed to determine the time interval between the adjacent triggers. The triggering condition is designed by using the current sampled consensus error. Furthermore, the consensus control protocol is designed by means of a state feedback approach. It is shown that the considered multi-agent systems can reach consensus with the presented algorithm. Some sufficient conditions are proposed in the form of linear matrix inequalities(LMIs) to show the positively invariant property of the domain of attraction(DOA). Moreover, some sufficient conditions of controller synthesis are provided to enlarge the volume of the DOA and obtain the control gain matrix. A numerical example is simulated to demonstrate the effectiveness of the theoretical analysis results.
文摘A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Field distribution in the switch section is regulated by a metal field regulation ring and several gradient rings. In order to reduce the jitter further, a SFB/N2 mixture is chosen as the switching medium. The generalized standard deviation of the self-breakdown voltage and the deviation of the average value from the prediction is less than 4.4% and 13% respectively. Linearity of the self-breakdown voltage is better than 0.95. Triggered by a laser pulse of 35 mJ/3 ns, the delay is about 26 ns at a working voltage of 85±3% USB （Self-breakdown Voltage）. Maximum deviation of delay is less than =t=2.5 ns. Jitter is less than 1.5 ns. The delay and jitter decrease with the increase in the working ratio （the ratio of working voltage to USB）, pressure or voltage.
文摘In the version of the article initially published,errors were identified in the figures,Figs.2Q and 6A,owing to the incorrect placement of images during the preparation and assembly of representative images.These revisions do not affect any results or conclusions in the article.The original data for these figures have been submitted to the Editorial Office,and access to this data can be obtained by contacting either the corresponding authors or the Editorial Office.
基金Supported by the National 863 CIMS Project Foundation(863-511-010)Tianjin Natural Science Foundation(983602011)Backbone Young Teacher Project Foundation of Ministry of Education
文摘This paper describes the self—adjustment of some tuning-knobs of the generalized predictive controller(GPC).A three feedforward neural network was utilized to on line learn two key tuning-knobs of GPC,and BP algorithm was used for the training of the linking-weights of the neural network.Hence it gets rid of the difficulty of choosing these tuning-knobs manually and provides easier condition for the wide applications of GPC on industrial plants.Simulation results illustrated the effectiveness of the method.
文摘The relation between structures and properties of polyurethane are investigated by modern physical and chemical methods.The results obtained are as follows:the effects of the content of self-crosslinking agent on the properties of polyurethane,i.e.,dispersion stability,dynamical viscoelasticity and mechanical properties are discussed.It is found that the optimum molar ratio of epichlorohydrin and diethylenetriamine is 1:2.A mois-
文摘The Belt and Road Initiative contains the aspiration of Chinese nation to pursue ideological freedom and desire of strengthening international exchanges and cooperation. This paper takes the Belt and Road Initiative for example,emphasizing the interpretation of the inheritance and development of Chinese culture so as to study the importance of Culture Self-Consciousness in Chinese Philosophy,in the context of English globalization. That is to say,this paper stresses the spirits and the stand of nation 's demonstration on pursuing peace,cooperation and sustainable development in the civilization continuity from traditional China to the contemporary China,with practical philosophic view.
基金support of this work by the Basic Research Development Program(2013CB834504)the National Natural Science Foundation of China(no.91027042,21321063 and 21474118)+1 种基金the“Strategic Priority Research Program”of the Chinese Academy of Sciences(XDB12020200)the Fund of the Chinese Academy of Sciences.
文摘Metallogels of an amphiphilic L-histidine derivative(LHC18)with various transition metal ions were investigated.It was found that while the amphiphile formed precipitates in aqueous solution when mixed with Cu^(2+),Zn^(2+),Ni^(2+),it formed a hydrogel with Fe^(3+).Interestingly,upon cooling the transparent solution of LHC18 with Fe^(3+)to room temperature gently without any interruption,the gel was formed.Upon further resting at room temperature,the gel underwent shrinkage and 90% of ferric water was expelled from the gel.On the other hand,if the as-formed gel was shaken or shear forces were applied,the gel would collapse into sol.The collapsed sol will recover to become the gel within one minute upon resting and the process can be repeated many times.In addition,once the gel experiences the thixotropic process,it will not shrink anymore.So far,various metallogels have been reported,and we show the first example of a metallogel that shows dual shrinkage and self-healing properties.
基金supported by the National Natural Science Foundation of China(Grant No.52172083)Zhejiang Province Key R&D Program:Vanguard and Leading Geese Projects(Grant No.2024C01190)+1 种基金the Guangzhou Key Research and Development Program(Grant No.2023B03J1239)Program for Innovative Research Team in University of Education System of Guangzhou(Grant No.202235404).
文摘Persistent luminescence has emerged as a robust platform for anti-counterfeiting applications due to its exceptional spatial-temporal decoding capability.Yet,conventional strategies often suffer from uniform emission patterns and predictable replication,compromising their security.Herein,we present“Snap-PLNPs”—near-infrared emitting CaS:Tm persistent luminescent nanoparticles engineered to undergo aqueous-triggered self-destruction via a hydrolysis mechanism.In contrast to traditional photophysical approaches,this chemically initiated degradation irreversibly terminates the luminescence,ensuring that security information can be decoded only once.Moreover,by incorporating an additional SiO_(2)shell,we introduce a programmable delay in the hydrolysis process,thereby modulating the duration of the emission and adding a temporal regulation layer.This dual control—combining instantaneous chemical deactivation with time-resolved modulation—establishes a dynamic hierarchical security encoding framework.When embedded into laser-engraved logos,these CaS:Tm@SiO_(2)hybrids enable a novel triple-layer anti-counterfeiting strategy that integrates spatial,temporal,and chemical dimensions.Our results underscore the potential of Snap-PLNPs as a next-generation platform for robust and adaptive security technologies.
基金supported by grants from the National Natural Science Foundation of China(Grant No.sU2139205,41774011,41874011)the National Key Research and Development Program of China(Grant No.2018YFC1503605)。
文摘Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.
文摘网络控制系统通过通信网络连接传感器、控制器和执行器,实现远程监控和智能控制,具有突破地域限制的优势,但其开放性和网络依赖性也引入了诸多问题。首先,系统分析了网络控制系统中存在的信号量化误差、数据包丢失、网络时延、带宽占用和网络安全威胁等问题;其次,在回顾网络控制系统研究成果的基础上,提出了新的控制策略,包括新型量化控制、随机丢包控制、时变时延的自触发控制、变采样周期智能调度控制、动态事件触发控制、DoS(denial of service)攻击的网络控制等;再次,归纳了相关的控制理论方法,包括随机系统法、预测控制法、时延估算与补偿、模糊反馈法、神经网络预测法;最后,提出了网络控制系统研究在未来面临的挑战。
