Oral dichloroacetate sodium(DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer...Oral dichloroacetate sodium(DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer cells. Response to therapy in human studies is measured by standard response evaluation criteria for solid tumours definitions, which define "response" by the degree of tumour reduction, or tumour disappearance on imaging. However, Blackburn et al have demonstrated that DCA can also act as a cytostatic agent in vitro and in vivo, without causing apoptosis(programmed cell death). A case is presented in which oral DCA therapy resulted in tumour stabilization of stage 4 colon cancer in a 57 years old female for a period of nearly 4 years, with no serious toxicity. Since the natural history of stage 4 colon cancer consists of steady progression leading to disability and death, this case highlights a novel use of DCA as a cytostatic agent with a potential to maintain long-term stability of advanced-stage cancer.展开更多
We propose an approach of long-term stabilization of optical fiber phase by controlling a piezo-based phase modulator and a Peltier component attached to the fiber via a phase-locked loop( PLL) circuit w ith dual prop...We propose an approach of long-term stabilization of optical fiber phase by controlling a piezo-based phase modulator and a Peltier component attached to the fiber via a phase-locked loop( PLL) circuit w ith dual proportional-integral- derivative( PID) adjustment. With this approach,we can suppress the fast disturbance and slow drifting of optical fiber to satisfy the requirements of optical phase long-term locking. In theory,a mathematical model of an optical fiber phase control system is established. The disturbance term induced by environment influence is considered into the PLL model. The monotonous and continuous changing environment disturbance w ill cause a steady-state error in this theory model. The experimental results accords w ell w ith the theory. The steady-state performance,adjusting time,and overshoot can be improved by using the dual PID control. As a result,the long-term,highly stable and low noise fiber phase locking is realized experimentally.展开更多
A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL...A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's stability.Additionally,a one-pulse-per-second(1PPS)is employed to syn-chronize the clock with GPS.Fabricated using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@100 Hz offset and-83.9 dBc/Hz@1 kHz offset,accompanied by a power dissipation of 19.7 mW.The Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×10^(-11) with 1-s averaging time.展开更多
This study examines the stabilization issue of extended chained nonholonomic systems(ECNSs)with external disturbance.Unlike the existing approaches,we transform the considered system into a fully actuated system(FAS)m...This study examines the stabilization issue of extended chained nonholonomic systems(ECNSs)with external disturbance.Unlike the existing approaches,we transform the considered system into a fully actuated system(FAS)model,simplifying the stabilizing controller design.We implement a separate controller design and propose exponential stabilization controller and finite-time stabilization controller under finite-time disturbance observer(FTDO)for the two system inputs.In addition,we discuss the specifics of global stabilization control design.Our approach demonstrates that two system states exponentially or asymptotically converge to zero under the provided switching stabilization control strategy,while all other system states converge to zero within a finite time.展开更多
Discrete feedback control was designed to stabilize an unstable hybrid neutral stochastic differential delay system(HNSDDS) under a highly nonlinear constraint in the H_∞ and exponential forms.Nevertheless,the existi...Discrete feedback control was designed to stabilize an unstable hybrid neutral stochastic differential delay system(HNSDDS) under a highly nonlinear constraint in the H_∞ and exponential forms.Nevertheless,the existing work just adapted to autonomous cases,and the obtained results were mainly on exponential stabilization.In comparison with autonomous cases,non-autonomous systems are of great interest and represent an important challenge.Accordingly,discrete feedback control has here been adjusted with a time factor to stabilize an unstable non-autonomous HNSDDS,in which new Lyapunov-Krasovskii functionals and some novel technologies are adopted.It should be noted,in particular,that the stabilization can be achieved not only in the routine H_∞ and exponential forms,but also the polynomial form and even a general form.展开更多
Dear Editor,This letter addresses the passivity-based mean square exponential stabilization problem for switched stochastic nonlinear systems.A concept of generalized small-time norm-observability is presented and an ...Dear Editor,This letter addresses the passivity-based mean square exponential stabilization problem for switched stochastic nonlinear systems.A concept of generalized small-time norm-observability is presented and an appropriate test condition is also provided.For pre-given passivity rate and average dwell time,a set of feedback controllers is designed by use of the passivity property.展开更多
Dear Editor,This letter deals with the set stabilization of stochastic Boolean control networks(SBCNs)by the pinning control strategy,which is to realize the full control for systems by imposing control inputs on a fr...Dear Editor,This letter deals with the set stabilization of stochastic Boolean control networks(SBCNs)by the pinning control strategy,which is to realize the full control for systems by imposing control inputs on a fraction of agents.展开更多
Dear Editor,to This letter deals with the output feedback stabilization of a class of high-order nonlinear time-delay systems with more general low-order and high-order nonlinearities.By constructing reduced-order obs...Dear Editor,to This letter deals with the output feedback stabilization of a class of high-order nonlinear time-delay systems with more general low-order and high-order nonlinearities.By constructing reduced-order observer,based on homogeneous domination theory together with the adding a power integrator method,an output feedback controller is developed guarantee the equilibrium of the closed system globally uniformly asymptotically stable.展开更多
Dear Editor,This letter presents a nonlinear robust controller design method for ship roll stabilization by combining the dual of Lyapunov's stability theorem with the sum of squares(SOS) technique. Varying initia...Dear Editor,This letter presents a nonlinear robust controller design method for ship roll stabilization by combining the dual of Lyapunov's stability theorem with the sum of squares(SOS) technique. Varying initial metacentric height and ship speed are regarded as uncertainties, sea waves are considered as external disturbances, and then the robust nonlinear controller is designed. Taking a container ship as an example, simulations are performed to verify the effectiveness of the proposed design scheme.展开更多
Up to 1.5wt%of Cr(Ⅲ)salts(CrCl_(3),and Cr_(2)O_(3))and Cr(Ⅵ)salts(Na_(2)CrO_(4),and CaCr_(2)O_(7))were incorporated into red mud-based geopolymers,respectively.The solidification/stabilization,compressive strength,a...Up to 1.5wt%of Cr(Ⅲ)salts(CrCl_(3),and Cr_(2)O_(3))and Cr(Ⅵ)salts(Na_(2)CrO_(4),and CaCr_(2)O_(7))were incorporated into red mud-based geopolymers,respectively.The solidification/stabilization,compressive strength,and durability of the Cr-containing geopolymers were investigated.The experimental results indicate that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates of above 99.61%.Geopolymers are environmentally safe when the dosage of CaCr_(2)O_(7)is≤1.0wt%,or the dosage of CrCl_(3),Cr_(2)O_(3),and Na_(2)CrO_(4)is≤1.5wt%,respectively.The effects of Cr salts on the compressive strength varies with the type and content of Cr salts.The freeze-thaw cycle is more destructive to geopolymer properties than sulfate attack or acid rain erosion.The solidification/stabilization of Cr is mainly attributed to the following reasons:a)The chemical binding of Cr is related to the formation of Cr-containing hydrates(eg,magnesiochromite((Mg,Fe)(Cr,Al)_(2)O_(4)))and doping into N-A-S-H gel and C-A-S-H gel framework;b)The physical effect is related to the encapsulation by the hydration products(e g,N-A-S-H gel and C-A-S-H gel).This study provides a reference for the treatment of hazardous Cr-containing wastes by solid waste-based geopolymers.展开更多
Layered-type transition metal(TM)oxides are considered as one of the most promising cathodes for K-ion batteries because of the large theoretical gravimetric capacity by low molar mass.However,they suffer from severe ...Layered-type transition metal(TM)oxides are considered as one of the most promising cathodes for K-ion batteries because of the large theoretical gravimetric capacity by low molar mass.However,they suffer from severe structural change by de/intercalation and diffusion of K^(+)ions with large ionic size,which results in not only much lower reversible capacity than the theoretical capacity but also poor power capability.Thus,it is important to enhance the structural stability of the layered-type TM oxides for outstanding electrochemical behaviors under the K-ion battery system.Herein,it is investigated that the substitution of the appropriate Ti^(4+)contents enables a highly enlarged reversible capacity of P3-type KxCrO_(2) using combined studies of first-principles calculation and various experiments.Whereas the pristine P3-type KxCrO_(2) just exhibits the reversible capacity of∼120 mAh g^(−1) in the voltage range of 1.5-4.0 V(vs.K^(+)/K),the∼0.61 mol K^(+)corresponding to∼150 mAh g^(−1) can be reversible de/intercalated at the structure of P3-type K0.71[Cr_(0.75)Ti_(0.25)]O_(2) under the same conditions.Furthermore,even at the high current density of 788 mA g^(−1),the specific capacity of P3-type K0.71[Cr_(0.75)Ti_(0.25)]O_(2) is∼120 mAh g^(−1),which is∼81 times larger than that of the pristine P3-type KxCrO_(2).It is believed that this research can provide an effective strategy to improve the electrochemical performances of the cathode materials suffered by severe structural change that occurred during charge/discharge under not only K-ion battery system but also other rechargeable battery systems.展开更多
Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate trackin...Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.展开更多
In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guar...In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guarantees the finite-time convergence property by assigning the control horizon equal to the dimension of the overall system, and only penalizing the terminal cost in the optimization, where the stage costs are not penalized explicitly. A terminal inequality constraint is added to guarantee the feasibility and stability of the closed-loop system.Initial feasibility can be improved via augmentation. The finite-time convergence of the proposed MPC is proved theoretically,and is supported by simulation examples.展开更多
A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevaryin...A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.展开更多
Set stabilization is one of the essential problems in engineering systems, and self-triggered control(STC) can save the storage space for interactive information, and can be successfully applied in networked control s...Set stabilization is one of the essential problems in engineering systems, and self-triggered control(STC) can save the storage space for interactive information, and can be successfully applied in networked control systems with limited communication resources. In this study, the set stabilization problem and STC design of Boolean control networks are investigated via the semi-tensor product technique. On the one hand, the largest control invariant subset is calculated in terms of the strongly connected components of the state transition graph, by which a graph-theoretical condition for set stabilization is derived. On the other hand, a characteristic function is exploited to determine the triggering mechanism and feasible controls. Based on this, the minimum-time and minimum-triggering open-loop, state-feedback and output-feedback STCs for set stabilization are designed,respectively. As classic applications of self-triggered set stabilization, self-triggered synchronization, self-triggered output tracking and self-triggered output regulation are discussed as well. Additionally, several practical examples are given to illustrate the effectiveness of theoretical results.展开更多
In this reported study, the density functional theory(DFT) was used at the(U)B3LYP/6-311G(d,p) level to investigate the stabilization process of the nitrate ester plasticized polyether propellant(NEPE). Molecular simu...In this reported study, the density functional theory(DFT) was used at the(U)B3LYP/6-311G(d,p) level to investigate the stabilization process of the nitrate ester plasticized polyether propellant(NEPE). Molecular simulations were conducted of the reaction that generates NO_(2), the autocatalytic and aging reaction triggered by the NO_(2), and the nitrogen dioxide absorption reaction of the stabilizers during the propellent stabilization process. These simulations were derived using the transition-state theory(TST)and variational transition-state theory(VTST). The simulation results suggested that the stabilization of the NEPE propellant consisted of three stages. First, heat and NO_(2) were generated during the denitrification reaction of nitroglycerine(NG) and 1,2,4-butanetriol trinitrate(BTTN) in the NEPE propellant.Second, nitroso products were generated by the reactions of N-Methyl-4-nitroaniline(MNA) and 2-nitrodiphenylamine(2NDPA) with NO_(2). Third, the stabilizers were exhausted and the autocatalytic reaction of NG and BTTN and the aging reaction of polyethylene glycol(PEG) were triggered by the heat and NO_(2)generated in the first stage. By comparing the energy barriers of the various reactions, it was found that the NO_(2)generated from the denitrification reaction significantly reduced the reaction energy barrier to 105.56-126.32 kJ/mol, also increased the reaction rate constant, and decreased the thermal stability and energetic properties of the NEPE propellant. In addition, the NO_(2)also weakened the mechanical properties of the NEPE propellant by attacking the-CH2groups and the O atoms in the PEG molecular chain. The energy barriers of the reactions of MNA and 2NDPA with NO_(2)(94.61-133.61 k J/mol) were lower than those of the autocatalytic and decomposition reactions of NG, BTTN, and the aging reactions of PEG(160.30-279.46 kJ/mol). This indicated that, by eliminating NO_(2), the stabilizer in the NEPE propellant can effectively prevent NO_(2)from reacting with the NG, BTTN, and PEG in the NEPE propellant. Consequently, this would help maintain the energy and mechanical properties of the NEPE propellant, thereby improving its thermal stability.展开更多
Dear Editor, This letter investigates the prescribed-time stabilization of linear singularly perturbed systems. Due to the numerical issues caused by the small perturbation parameter, the off-the-shelf control design ...Dear Editor, This letter investigates the prescribed-time stabilization of linear singularly perturbed systems. Due to the numerical issues caused by the small perturbation parameter, the off-the-shelf control design techniques for the prescribed-time stabilization of regular linear systems are typically not suitable here. To solve the problem, the decoupling transformation techniques for time-varying singularly perturbed systems are combined with linear time-varying high gain feedback design techniques.展开更多
The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphi...The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)surface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite interface.Additionally,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite interface.Consequently,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,respectively.Moreover,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability.Besides,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our strategies.Of particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively.展开更多
In this work,we developed the PM6:Y6-based inverted structure organic photovoltaic(i-OPV)with improved power conversion efficiency(PCE)and long-term stability by resolving the origins of the performance deterioration....In this work,we developed the PM6:Y6-based inverted structure organic photovoltaic(i-OPV)with improved power conversion efficiency(PCE)and long-term stability by resolving the origins of the performance deterioration.The deep defects between the metal oxide-based electron transport layer and bulk-heterojunction photoactive layer interface were responsible for suboptimal PCE and facilitated degradation of devices.While the density of deep traps is increased during the storage of i-OPV,the penetrative oxygen-containing defects additionally generated shallow traps below the band-edge of Y6,causing an additional loss in the open-circuit voltage.The suppression of interfacial defects by chemical modification effectively improved the PCE and long-term stability of i-OPV.The modified i-OPV(mi-OPV)achieved a PCE of 17.42%,which is the highest value among the reported PM6:Y6-based i-OPV devices.Moreover,long-term stability was significantly improved:~90%and~80%retention of its initial PCE after 1200 h of air storage and illumination,respectively.展开更多
Coral sand is widely encountered in coastal areas of tropical and subtropical regions.Compared with silica sand,it usually exhibits weaker performance from the perspective of engineering geology.To improve the geomech...Coral sand is widely encountered in coastal areas of tropical and subtropical regions.Compared with silica sand,it usually exhibits weaker performance from the perspective of engineering geology.To improve the geomechanical performance of coral sand and meet the requirement of foundation construction in coastal areas,a novel alkali activation-based sustainable binder was developed.The alkaliactivated slag(AAS)binder material was composed of ground granulated blast-furnace slag(GGBS)and hydrated lime with the amendment of biochar,an agricultural waste-derived material.The biocharamended AAS stabilized coral sand was subjected to a series of laboratory tests to determine its mechanical,physicochemical,and microstructural characteristics.Results show that adding a moderate amount of biochar in AAS could improve soil strength,elastic modulus,and water holding capacity by up to 20%,70%,and 30%,respectively.Moreover,the addition of biochar in AAS had a marginal effect on the sulfate resistance of the stabilized sand,especially at high biochar content.However,the resistance of the AAS stabilized sand to wet-dry cycles slightly deteriorated with the addition of biochar.Based on these observations,a conceptual model showing biochar-AAS-sand interactions was proposed,in which biochar served as an internal curing agent,micro-reinforcer,and mechanically weak point.展开更多
文摘Oral dichloroacetate sodium(DCA) has been investigated as a novel metabolic therapy for various cancers since 2007, based on data from Bonnet et al that DCA can trigger apoptosis of human lung, breast and brain cancer cells. Response to therapy in human studies is measured by standard response evaluation criteria for solid tumours definitions, which define "response" by the degree of tumour reduction, or tumour disappearance on imaging. However, Blackburn et al have demonstrated that DCA can also act as a cytostatic agent in vitro and in vivo, without causing apoptosis(programmed cell death). A case is presented in which oral DCA therapy resulted in tumour stabilization of stage 4 colon cancer in a 57 years old female for a period of nearly 4 years, with no serious toxicity. Since the natural history of stage 4 colon cancer consists of steady progression leading to disability and death, this case highlights a novel use of DCA as a cytostatic agent with a potential to maintain long-term stability of advanced-stage cancer.
基金supported by the National Natural Science Foundation of China(Grant No.91436103)Research Programme of National University of Defense Technology(Grant No.JC15-02-03)
文摘We propose an approach of long-term stabilization of optical fiber phase by controlling a piezo-based phase modulator and a Peltier component attached to the fiber via a phase-locked loop( PLL) circuit w ith dual proportional-integral- derivative( PID) adjustment. With this approach,we can suppress the fast disturbance and slow drifting of optical fiber to satisfy the requirements of optical phase long-term locking. In theory,a mathematical model of an optical fiber phase control system is established. The disturbance term induced by environment influence is considered into the PLL model. The monotonous and continuous changing environment disturbance w ill cause a steady-state error in this theory model. The experimental results accords w ell w ith the theory. The steady-state performance,adjusting time,and overshoot can be improved by using the dual PID control. As a result,the long-term,highly stable and low noise fiber phase locking is realized experimentally.
基金supported by the National Natural Science Foundation of China under Grant 62034002 and 62374026.
文摘A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's stability.Additionally,a one-pulse-per-second(1PPS)is employed to syn-chronize the clock with GPS.Fabricated using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@100 Hz offset and-83.9 dBc/Hz@1 kHz offset,accompanied by a power dissipation of 19.7 mW.The Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×10^(-11) with 1-s averaging time.
基金partially supported by the National Natural Science Foundation of China(62173207,62073187)the Science Center Program of the National Natural Science Foundation of China(62188101)+1 种基金the China Postdoctoral Science Special Foundation(2023T160334)the Youth Innovation Team Project of Colleges and Universities in Shandong Province(2022KJ176)。
文摘This study examines the stabilization issue of extended chained nonholonomic systems(ECNSs)with external disturbance.Unlike the existing approaches,we transform the considered system into a fully actuated system(FAS)model,simplifying the stabilizing controller design.We implement a separate controller design and propose exponential stabilization controller and finite-time stabilization controller under finite-time disturbance observer(FTDO)for the two system inputs.In addition,we discuss the specifics of global stabilization control design.Our approach demonstrates that two system states exponentially or asymptotically converge to zero under the provided switching stabilization control strategy,while all other system states converge to zero within a finite time.
基金supported by the National Natural Science Foundation of China(61833005)the Humanities and Social Science Fund of Ministry of Education of China(23YJAZH031)+1 种基金the Natural Science Foundation of Hebei Province of China(A2023209002,A2019209005)the Tangshan Science and Technology Bureau Program of Hebei Province of China(19130222g)。
文摘Discrete feedback control was designed to stabilize an unstable hybrid neutral stochastic differential delay system(HNSDDS) under a highly nonlinear constraint in the H_∞ and exponential forms.Nevertheless,the existing work just adapted to autonomous cases,and the obtained results were mainly on exponential stabilization.In comparison with autonomous cases,non-autonomous systems are of great interest and represent an important challenge.Accordingly,discrete feedback control has here been adjusted with a time factor to stabilize an unstable non-autonomous HNSDDS,in which new Lyapunov-Krasovskii functionals and some novel technologies are adopted.It should be noted,in particular,that the stabilization can be achieved not only in the routine H_∞ and exponential forms,but also the polynomial form and even a general form.
基金supported by the National Natural Science Foundation of China(U23A20324,62201510)the 111 Project(B16009)+1 种基金the Henan Provincial Department of Science and Technology Research Project(212102310299)the Open Foundation of Henan Key Laboratory of General Aviation Technology(ZHKF-230206)。
文摘Dear Editor,This letter addresses the passivity-based mean square exponential stabilization problem for switched stochastic nonlinear systems.A concept of generalized small-time norm-observability is presented and an appropriate test condition is also provided.For pre-given passivity rate and average dwell time,a set of feedback controllers is designed by use of the passivity property.
基金supported by the National Key Research and Development Project of China(2020YFA0714301)the National Natural Science Foundation of China(61833005)。
文摘Dear Editor,This letter deals with the set stabilization of stochastic Boolean control networks(SBCNs)by the pinning control strategy,which is to realize the full control for systems by imposing control inputs on a fraction of agents.
基金supported by the National Natural Science Foundation of China(62103175)Taishan Scholar Project of Shandong Province of China。
文摘Dear Editor,to This letter deals with the output feedback stabilization of a class of high-order nonlinear time-delay systems with more general low-order and high-order nonlinearities.By constructing reduced-order observer,based on homogeneous domination theory together with the adding a power integrator method,an output feedback controller is developed guarantee the equilibrium of the closed system globally uniformly asymptotically stable.
基金supported by the National Natural Science Foundation of Jiangsu Province (BK20231112)。
文摘Dear Editor,This letter presents a nonlinear robust controller design method for ship roll stabilization by combining the dual of Lyapunov's stability theorem with the sum of squares(SOS) technique. Varying initial metacentric height and ship speed are regarded as uncertainties, sea waves are considered as external disturbances, and then the robust nonlinear controller is designed. Taking a container ship as an example, simulations are performed to verify the effectiveness of the proposed design scheme.
基金Funded by the National Natural Science Foundation of China(Nos.52074245,52374416 and 52202029)the China Postdoctoral Science Foundation(No.2022M721058)。
文摘Up to 1.5wt%of Cr(Ⅲ)salts(CrCl_(3),and Cr_(2)O_(3))and Cr(Ⅵ)salts(Na_(2)CrO_(4),and CaCr_(2)O_(7))were incorporated into red mud-based geopolymers,respectively.The solidification/stabilization,compressive strength,and durability of the Cr-containing geopolymers were investigated.The experimental results indicate that the red mud-based geopolymer could effectively solidify/stabilize different types of Cr salts with solidification/stabilization rates of above 99.61%.Geopolymers are environmentally safe when the dosage of CaCr_(2)O_(7)is≤1.0wt%,or the dosage of CrCl_(3),Cr_(2)O_(3),and Na_(2)CrO_(4)is≤1.5wt%,respectively.The effects of Cr salts on the compressive strength varies with the type and content of Cr salts.The freeze-thaw cycle is more destructive to geopolymer properties than sulfate attack or acid rain erosion.The solidification/stabilization of Cr is mainly attributed to the following reasons:a)The chemical binding of Cr is related to the formation of Cr-containing hydrates(eg,magnesiochromite((Mg,Fe)(Cr,Al)_(2)O_(4)))and doping into N-A-S-H gel and C-A-S-H gel framework;b)The physical effect is related to the encapsulation by the hydration products(e g,N-A-S-H gel and C-A-S-H gel).This study provides a reference for the treatment of hazardous Cr-containing wastes by solid waste-based geopolymers.
基金Korea Institute of Materials Science,Grant/Award Number:PNK9370National Research Foundation of Korea,Grant/Award Numbers:NRF-2021R1A2C1014280,NRF-2022R1C1C1011058,NRF-2022M3H446401037201Korea Institute of Science and Technology,Grant/Award Number:2E32581-23-092。
文摘Layered-type transition metal(TM)oxides are considered as one of the most promising cathodes for K-ion batteries because of the large theoretical gravimetric capacity by low molar mass.However,they suffer from severe structural change by de/intercalation and diffusion of K^(+)ions with large ionic size,which results in not only much lower reversible capacity than the theoretical capacity but also poor power capability.Thus,it is important to enhance the structural stability of the layered-type TM oxides for outstanding electrochemical behaviors under the K-ion battery system.Herein,it is investigated that the substitution of the appropriate Ti^(4+)contents enables a highly enlarged reversible capacity of P3-type KxCrO_(2) using combined studies of first-principles calculation and various experiments.Whereas the pristine P3-type KxCrO_(2) just exhibits the reversible capacity of∼120 mAh g^(−1) in the voltage range of 1.5-4.0 V(vs.K^(+)/K),the∼0.61 mol K^(+)corresponding to∼150 mAh g^(−1) can be reversible de/intercalated at the structure of P3-type K0.71[Cr_(0.75)Ti_(0.25)]O_(2) under the same conditions.Furthermore,even at the high current density of 788 mA g^(−1),the specific capacity of P3-type K0.71[Cr_(0.75)Ti_(0.25)]O_(2) is∼120 mAh g^(−1),which is∼81 times larger than that of the pristine P3-type KxCrO_(2).It is believed that this research can provide an effective strategy to improve the electrochemical performances of the cathode materials suffered by severe structural change that occurred during charge/discharge under not only K-ion battery system but also other rechargeable battery systems.
基金the National Natural Science Foundation of China(No.52275062)and(No.52075262).
文摘Since backlash nonlinearity is inevitably existing in actuators for bidirectional stabilization system of allelectric tank,it behaves more drastically in high maneuvering environments.In this work,the accurate tracking control for bidirectional stabilization system of moving all-electric tank with actuator backlash and unmodeled disturbance is solved.By utilizing the smooth adaptive backlash inverse model,a nonlinear robust adaptive feedback control scheme is presented.The unknown parameters and unmodelled disturbance are addressed separately through the derived parametric adaptive function and the continuous nonlinear robust term.Because the unknown backlash parameters are updated via adaptive function and the backlash effect can be suppressed successfully by inverse operation,which ensures the system stability.Meanwhile,the system disturbance in the high maneuverable environment can be estimated with the constructed adaptive law online improving the engineering practicality.Finally,Lyapunov-based analysis proves that the developed controller can ensure the tracking error asymptotically converges to zero even with unmodeled disturbance and unknown actuator backlash.Contrast co-simulations and experiments illustrate the advantages of the proposed approach.
基金supported by the National Natural Science Foundation of China (62073015,62173036,62122014)。
文摘In this paper, a model predictive control(MPC)framework is proposed for finite-time stabilization of linear and nonlinear discrete-time systems subject to state and control constraints. The proposed MPC framework guarantees the finite-time convergence property by assigning the control horizon equal to the dimension of the overall system, and only penalizing the terminal cost in the optimization, where the stage costs are not penalized explicitly. A terminal inequality constraint is added to guarantee the feasibility and stability of the closed-loop system.Initial feasibility can be improved via augmentation. The finite-time convergence of the proposed MPC is proved theoretically,and is supported by simulation examples.
基金supported in part by the Nation Natural Science Foundation of China under Grant No.52175099China Postdoctoral Science Foundation under Grant No.2020M671494Jiangsu Planned Projects for Postdoctoral Research Funds under Grant No.2020Z179。
文摘A tracking stability control problem for the vertical electric stabilization system of moving tank based on adaptive robust servo control is addressed.This paper mainly focuses on two types of possibly fast timevarying but bounded uncertainty within the vertical electric stabilization system:model parameter uncertainty and uncertain nonlinearity.First,the vertical electric stabilization system is constructed as an uncertain nonlinear dynamic system that can reflect the practical mechanics transfer process of the system.Second,the dynamical equation in the form of state space is established by designing the angular tracking error.Third,the comprehensive parameter of system uncertainty is designed to estimate the most conservative effects of uncertainty.Finally,an adaptive robust servo control which can effectively handle the combined effects of complex nonlinearity and uncertainty is proposed.The feasibility of the proposed control strategy under the practical physical condition is validated through the tests on the experimental platform.This paper pioneers the introduction of the internal nonlinearity and uncertainty of the vertical electric stabilization system into the settlement of the tracking stability control problem,and validates the advanced servo control strategy through experiment for the first time.
基金supported by the National Natural Science Foundation of China (62273201,62173209,72134004,62303170)the Research Fund for the Taishan Scholar Project of Shandong Province of China (TSTP20221103)。
文摘Set stabilization is one of the essential problems in engineering systems, and self-triggered control(STC) can save the storage space for interactive information, and can be successfully applied in networked control systems with limited communication resources. In this study, the set stabilization problem and STC design of Boolean control networks are investigated via the semi-tensor product technique. On the one hand, the largest control invariant subset is calculated in terms of the strongly connected components of the state transition graph, by which a graph-theoretical condition for set stabilization is derived. On the other hand, a characteristic function is exploited to determine the triggering mechanism and feasible controls. Based on this, the minimum-time and minimum-triggering open-loop, state-feedback and output-feedback STCs for set stabilization are designed,respectively. As classic applications of self-triggered set stabilization, self-triggered synchronization, self-triggered output tracking and self-triggered output regulation are discussed as well. Additionally, several practical examples are given to illustrate the effectiveness of theoretical results.
基金the support provided by the School of Physics and Optoelectronic Engineering of Ludong University。
文摘In this reported study, the density functional theory(DFT) was used at the(U)B3LYP/6-311G(d,p) level to investigate the stabilization process of the nitrate ester plasticized polyether propellant(NEPE). Molecular simulations were conducted of the reaction that generates NO_(2), the autocatalytic and aging reaction triggered by the NO_(2), and the nitrogen dioxide absorption reaction of the stabilizers during the propellent stabilization process. These simulations were derived using the transition-state theory(TST)and variational transition-state theory(VTST). The simulation results suggested that the stabilization of the NEPE propellant consisted of three stages. First, heat and NO_(2) were generated during the denitrification reaction of nitroglycerine(NG) and 1,2,4-butanetriol trinitrate(BTTN) in the NEPE propellant.Second, nitroso products were generated by the reactions of N-Methyl-4-nitroaniline(MNA) and 2-nitrodiphenylamine(2NDPA) with NO_(2). Third, the stabilizers were exhausted and the autocatalytic reaction of NG and BTTN and the aging reaction of polyethylene glycol(PEG) were triggered by the heat and NO_(2)generated in the first stage. By comparing the energy barriers of the various reactions, it was found that the NO_(2)generated from the denitrification reaction significantly reduced the reaction energy barrier to 105.56-126.32 kJ/mol, also increased the reaction rate constant, and decreased the thermal stability and energetic properties of the NEPE propellant. In addition, the NO_(2)also weakened the mechanical properties of the NEPE propellant by attacking the-CH2groups and the O atoms in the PEG molecular chain. The energy barriers of the reactions of MNA and 2NDPA with NO_(2)(94.61-133.61 k J/mol) were lower than those of the autocatalytic and decomposition reactions of NG, BTTN, and the aging reactions of PEG(160.30-279.46 kJ/mol). This indicated that, by eliminating NO_(2), the stabilizer in the NEPE propellant can effectively prevent NO_(2)from reacting with the NG, BTTN, and PEG in the NEPE propellant. Consequently, this would help maintain the energy and mechanical properties of the NEPE propellant, thereby improving its thermal stability.
基金supported by the National Natural Science Foundation of China(62173152,62103156,62233006)the Natural Science Foundation of Hubei Province of China(2021CFB052)the China Postdoctoral Science Foundation(2022M721249)。
文摘Dear Editor, This letter investigates the prescribed-time stabilization of linear singularly perturbed systems. Due to the numerical issues caused by the small perturbation parameter, the off-the-shelf control design techniques for the prescribed-time stabilization of regular linear systems are typically not suitable here. To solve the problem, the decoupling transformation techniques for time-varying singularly perturbed systems are combined with linear time-varying high gain feedback design techniques.
基金supported by the National Key Research and Development Program of China(2018YFA0208701)the National Natural Science Foundation of China(21773308)+7 种基金the Research Funds of Renmin University of China(2017030013,201903020 and 20XNH059)the Fundamental Research Funds for Central Universities(China)supported by the Solar Energy Research Institute of Singapore(SERIS) at the National University of Singapore(NUS)supported by NUSthe National Research Foundation Singapore(NRF)the Energy Market Authority of Singapore(EMA)the Singapore Economic Development Board(EDB)the financial support from the China Scholarship Council(CSC) funding。
文摘The presence of defects and detrimental reactions at NiO_(x)/perovskite interface extremely limit the efficiency performance and long-term stability of the perovskite solar cells(PSCs) based on NiO_(x).Herein,an amphipathic molecule Triton X100(Triton) is modified on the NiO_(x)surface.The hydrophilic chain of Triton as a Lewis base additive can coordinate with the Ni3+on the NiO_(x)surface which can passivate the interfacial defects and hinder the detrimental reactions at the NiO_(x)/perovskite interface.Additionally,the hydrophobic chain of Triton protrudes from the NiO_(x)surface to prevent moisture from penetrating into the NiO_(x)/perovskite interface.Consequently,the NiO_(x)/Triton-based devices(MAPbI3as absorbing layer) show superior moisture and thermal stability,retaining 88.4% and 64.3% of the initial power conversion efficiency after storage in air(40%-50% relative humidity(RH)) at 25 ℃ for 1070 h and in N2at 85℃ for 800 h,respectively.Moreover,the efficiency increases from 17.59% to 19.89% because of the passivation defect and enhanced hole-extraction capability.Besides,the NiO_(x)/Triton-based PSCs with Cs_(0.05)(MA_(0.15)FA_(0.85))_(0.95)Pb(I_(0.85)Br_(0.15))3perovskite as the light-absorbing layer also exhibits better moisture and thermal stability compared to the control devices,indicating the viability of our strategies.Of particular note,a champion PCE of 22.35% and 20.46% was achieved for small-area(0.1 cm^(2)) and large-area(1.2 cm^(2)) NiO_(x)/Triton-based devices,respectively.
基金supported by a National Research Foundation of Korea(grant#:2020R1A2C1003929,2019R1A6A1A11053838,2020M1A2A2080746,2021M2E8A1044198,2016R1A5A1012966,2021M3H4A1A03051379).
文摘In this work,we developed the PM6:Y6-based inverted structure organic photovoltaic(i-OPV)with improved power conversion efficiency(PCE)and long-term stability by resolving the origins of the performance deterioration.The deep defects between the metal oxide-based electron transport layer and bulk-heterojunction photoactive layer interface were responsible for suboptimal PCE and facilitated degradation of devices.While the density of deep traps is increased during the storage of i-OPV,the penetrative oxygen-containing defects additionally generated shallow traps below the band-edge of Y6,causing an additional loss in the open-circuit voltage.The suppression of interfacial defects by chemical modification effectively improved the PCE and long-term stability of i-OPV.The modified i-OPV(mi-OPV)achieved a PCE of 17.42%,which is the highest value among the reported PM6:Y6-based i-OPV devices.Moreover,long-term stability was significantly improved:~90%and~80%retention of its initial PCE after 1200 h of air storage and illumination,respectively.
基金supported by the Hawaii Department of Transportation(Grant No.2020-4ReSUPP)National Natural Science Foundation of China(Grant No.42007246)Fundamental Research Funds for the Central Universities.
文摘Coral sand is widely encountered in coastal areas of tropical and subtropical regions.Compared with silica sand,it usually exhibits weaker performance from the perspective of engineering geology.To improve the geomechanical performance of coral sand and meet the requirement of foundation construction in coastal areas,a novel alkali activation-based sustainable binder was developed.The alkaliactivated slag(AAS)binder material was composed of ground granulated blast-furnace slag(GGBS)and hydrated lime with the amendment of biochar,an agricultural waste-derived material.The biocharamended AAS stabilized coral sand was subjected to a series of laboratory tests to determine its mechanical,physicochemical,and microstructural characteristics.Results show that adding a moderate amount of biochar in AAS could improve soil strength,elastic modulus,and water holding capacity by up to 20%,70%,and 30%,respectively.Moreover,the addition of biochar in AAS had a marginal effect on the sulfate resistance of the stabilized sand,especially at high biochar content.However,the resistance of the AAS stabilized sand to wet-dry cycles slightly deteriorated with the addition of biochar.Based on these observations,a conceptual model showing biochar-AAS-sand interactions was proposed,in which biochar served as an internal curing agent,micro-reinforcer,and mechanically weak point.