Single-atom nanozymes(SAzymes)exhibit exceptional catalytic efficiency due to their maximized atom utilization and precisely modulated metalcarrier interactions,which have attracted significant attention in the biomed...Single-atom nanozymes(SAzymes)exhibit exceptional catalytic efficiency due to their maximized atom utilization and precisely modulated metalcarrier interactions,which have attracted significant attention in the biomedical field.However,stability issues may impede the clinical translation of SAzymes.This review provides a comprehensive overview of the applications of SAzymes in various biomedical fields,including disease diagnosis(e.g.,biosensors and diagnostic imaging),antitumor therapy(e.g.,photothermal therapy,photodynamic therapy,sonodynamic therapy,and immunotherapy),antimicrobial therapy,and anti-oxidative stress therapy.More importantly,the existing challenges of SAzymes are discussed,such as metal atom clustering and active site loss,ligand bond breakage at high temperature,insufficient environment tolerance,biosecurity risks,and limited catalytic long-term stability.Finally,several innovative strategies to address these stability concerns are proposed—synthesis process optimization(space-limited strategy,coordination site design,bimetallic synergistic strategy,defect engineering strategy,atom stripping-capture),surface modification,and dynamic responsive design—that collectively pave the way for robust,clinically viable SAzymes.展开更多
Existing literature has shown that the control force at the nose could cause dynamic instability for controlled projectiles. To lower the adverse impact on the dual-spin projectile with fixed canards under the premise...Existing literature has shown that the control force at the nose could cause dynamic instability for controlled projectiles. To lower the adverse impact on the dual-spin projectile with fixed canards under the premise of meeting guidance system requirements, the influence of control moment provided by a motor on the flight stability is analyzed in this paper. Firstly, the effect of the rolling movement on stability is analyzed based on the stability criterion derived using the Hurwitz stability theory. Secondly, the evaluation parameters combining the features of different control periods that could assess the variation of stability features after the motor torque are obtained. These effective formulas are used to indicate that, to reduce the flight instability risks, the stabilized rolling speed of roll speed keeping period should be as small as possible; the variation trend of motor torque during the rolling speed controlling period and the roll angle of the forward body during roll angle switching period are recommended corresponding to the projectile and trajectory characteristics. Moreover,detailed numerical simulations of 155 mm dual-spin projectile are satisfactory agreement with the theoretical results.展开更多
Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evo...Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evolution reaction(HER),and corrosion side reactions.Herein,we propose a surface engineering modification strategy for coating the montmorillonite(MMT)layer onto the surface of the Zn anode to tackle these issues,thereby achieving high cycling stability for rechargeable AZIBs.The results reveal that the MMT layer on the surface of the Zn anode is able to provide ordered zincophilic channels for zinc ions migration,facilitating the reaction kinetics of zinc ions.Density functional theory(DFT)calculations and water contact angle(CA)tests prove that MMT@Zn anode exhibits superior adsorption capacity for Zn^(2+)and better hydrophobicity than the bare Zn anode,thereby achieving excellent cycling stability.Moreover,the MMT@Zn||MMT@Zn symmetric cell holds the stable cycling over 5600 h at 0.5 mA cm^(-2)and 0.125 m A h cm^(-2),even exceeding 1800 h long cycling under harsh conditions of 5 m A cm^(-2)and 1.25 m A h cm^(-2).The MMT@Zn||V_(2)O_(5)full cell reaches over 3000 cycles at 2 A g^(-1)with excellent rate capability.Therefore,this surface engineering modification strategy for enhancing the electrochemical performance of AZIBs represents a promising application.展开更多
Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required...Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport,which determines superior photoresponse and high stability.Herein,a general thermal-pressed(TP)strategy is designed to solve the above issues,achieving uniaxial orientation and single-grain penetration along the film thickness direction.It constructs the efficient channel for ordered carrier transport between two electrodes.Combining of the improved crystal quality and lower trap-state density,the quasi-2D and 3D perovskite-based self-powered photodetector devices(with/without hole transport layer)all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser.For the MAPbI_(3)-based self-powered photodetectors,the largest R_(λ) value is as high as 0.57 A W^(−1)at 760 nm,which is larger than most reported results.Meanwhile,under laser illumination(532 nm),the FPEA_(2)MA_(4)Pb_(5)I_(16)-based device exhibits a high responsivity(0.4 A W^(−1)) value,which is one of the best results in 2DRP self-powered photodetectors.In addition,fast response,ultralow detection limit,and markedly improved humidity,optical and heat stabilities are clearly demonstrated for these TP-based devices.展开更多
Gasoline compression ignition (GCI) is one of the most promising combustion concepts to maintain low pollutant emissions and high efficiency. However, low load combustion stability and firing in cold-start operations ...Gasoline compression ignition (GCI) is one of the most promising combustion concepts to maintain low pollutant emissions and high efficiency. However, low load combustion stability and firing in cold-start operations are two major challenges for GCI combustion. Strategies including negative valve overlap (NVO), advanced injection strategies, fuel reforming, and intake preheating have been proposed in order to solve these difficulties;however, the cold start is still an obstacle. The objective of this work is to study effective methods to achieve GCI engine cold start-up. This work combines NVO, in-cylinder fuel reforming, and intake preheating to achieve quick firing under cold-start conditions and the subsequent warmup conditions. The results show that start of injection (SOI) during the intake stroke yields the best fuel economy, and injection during the compression stroke has the potential to extend the low load limit. Furthermore, SOI during the NVO period grants the ability to operate under engine conditions with cold intake air and coolant. With highly reactive products made by in-cylinder fuel reforming and fast heat accumulation in the combustion chamber, the NVO injection strategy is highly appropriate for GCI firing. An additional assisted technical method, such as intake preheating, is required to ignite the first firing cycle for a cold-start process. With the combination of NVO, in-cylinder fuel reforming, and intake preheating, the GCI engine successfully started within five combustion cycles in the experiment. After the firing process, the engine could stably operate without further intake preheating;thus, this method is appropriate for engine cold-start and warm-up.展开更多
MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, th...MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.展开更多
In a previous work(2018,Commun.Theor.Phys.70,795–802),a new compartment model for the spreading of rumors was introduced and analyzed.However,only the local asymptotic stability of this model was discussed.In the pre...In a previous work(2018,Commun.Theor.Phys.70,795–802),a new compartment model for the spreading of rumors was introduced and analyzed.However,only the local asymptotic stability of this model was discussed.In the present work,we first provide a rigorous mathematical analysis for the global asymptotic stability(GAS)of the above-mentioned rumor spreading model.By constructing suitable Lyapunov candidate functions,we obtain the GAS of a rumor-free(boundary)equilibrium point and a unique rumor-spreading(positive)equilibrium point.After that,we utilize the approach based on the Lyapunov candidate functions to study the GAS of another rumor spreading model with control strategies,which was proposed in(2022,Physica A 606,128157).As an important consequence,the GAS of the rumor spreading model with control strategies is determined fully without resorting to technical hypotheses used in the benchmark work.Lastly,the theoretical findings are supported by a set of illustrative numerical examples.The obtained results not only improve the ones constructed in the two abovementioned benchmark papers but also can be extended to study the global dynamics of other rumor propagation models in the context of both integer-order and fractional-order derivatives.展开更多
This paper considers the problem of simultaneous estimation of the system states and the strategy of commutation for a larger class of nonlinear switched systems.First,a hybrid high gain observer is considered to get ...This paper considers the problem of simultaneous estimation of the system states and the strategy of commutation for a larger class of nonlinear switched systems.First,a hybrid high gain observer is considered to get the exact estimation of the continuous states where the strategy of switching is previously known.Then,an extension to a larger class of nonlinear hybrid systems with arbitrary switching is made.Stability analysis is widely discussed for the two cases to provide a finite-time convergence of the estimation errors.The effectiveness of the proposed hybrid high gain observer has been proved by applying it to a quadruple tank process.展开更多
Water splitting with proton exchange membrane water electrolyzers(PEMWE)is regarded as a promising pathway for sustainable hydrogen conversion.Additionally,oxygen evolution reaction(OER)is considered as the dominant f...Water splitting with proton exchange membrane water electrolyzers(PEMWE)is regarded as a promising pathway for sustainable hydrogen conversion.Additionally,oxygen evolution reaction(OER)is considered as the dominant factor during the whole process due to the sluggish kinetics.Among the catalysts,Rubased catalysts draw special attention because of their excellent activity and relatively low price.However,the limited stability impedes their further commercialization and tremendous efforts have been devoted to overcome this challenge.This review firstly introduces the basic mechanisms of OER.Then the evaluation protocols and techniques to investigate the stability of Ru-based catalysts are summarized.A detailed elucidation of the possible degradation mechanisms is also critically analyzed.Furthermore,effective strategies to design durable Ru-based catalysts for acidic OER are discussed.Such as heteroatom doping,phase and facet engineering,heterostructure building and support optimization.Finally,promises,perspectives and challenges in developing highly durable Ru-based catalysts for acidic OER are outlined.展开更多
An extended car-following model with multiple delays is constructed to describe driver's driving behavior.Through stability analysis,the stability condition of this uncontrolled model is given.To dampen the negati...An extended car-following model with multiple delays is constructed to describe driver's driving behavior.Through stability analysis,the stability condition of this uncontrolled model is given.To dampen the negative impact of the driver's multiple delays(i.e.,stability condition is not satisfied),a novel control strategy is proposed to assist the driver in adjusting vehicle operation.The control strategy consists of two parts:the design of control term as well as the design of the parameters in the term.Bifurcation analysis is performed to illustrate the necessity of the design of parameters in control terms.In the course of the design of parameters in the control term,we improve the definite integral stability method to reduce the iterations by incorporating the characteristics of bifurcation,which can determine the appropriate parameters in the control terms more quickly.Finally,in the case study,we validate the control strategy by utilizing measured data and configuring scenario,which is closer to the actual traffic.The results of validation show that the control strategy can effectively stabilize the unstable traffic flow caused by driver's delays.展开更多
In this paper, transient stability analysis was focused on Hu-Liao HVDC and AC parallel transmission system. The Hu-Liao HVDC project was introduced;Simulation method and mathematic models of AC and DC systems were st...In this paper, transient stability analysis was focused on Hu-Liao HVDC and AC parallel transmission system. The Hu-Liao HVDC project was introduced;Simulation method and mathematic models of AC and DC systems were stu-died as well as corresponding regulators and controllers. The dynamic performance and the interaction between AC and DC systems during serious disturbance were researched by detail time-domain simulation. Comparison was also made under different operation schemes. The research will bring important and significant reference for further operation and stability control of Hu-Liao HVDC and AC system.展开更多
With the continuous growth of China's economy,financial opening to the outside world has become one of the important means to promote economic development.However,with the continuous acceleration of capital flow,t...With the continuous growth of China's economy,financial opening to the outside world has become one of the important means to promote economic development.However,with the continuous acceleration of capital flow,the problem of balance in and out is becoming increasingly prominent.Taking China's financial opening to the outside world as the research object,this paper discusses how China strategically achieves the balance of entry and exit in the field of financial opening to the outside world,and the impact of this balance.Through the quantitative analysis of China's financial opening to the outside world and foreign capital flows,it is found that China needs to strengthen the management of capital items and optimize the structure of capital flows in the process of financial opening to the outside world,to achieve the balance of financial flows in and out.As for the impact of the balance of access and access,the analysis of the impact mechanism shows that the financial opening and access and balance can improve the stability of the financial market,provide sufficient liquidity for the healthy development of the financial market,and alleviate financial risks.Such a strategy is of great practical significance for promoting the sustained and healthy development of China's economy.Therefore,based on the actual situation of China,this paper puts forward some relevant strategy suggestions to guide the practical operation of China's financial opening up.展开更多
Persistent illumination inevitably leads to the formation of Pb^(0)and I^(0)species in perovskite film,serving as non-radiative recombination centers and thus limiting the process of the commercial application.Herein,...Persistent illumination inevitably leads to the formation of Pb^(0)and I^(0)species in perovskite film,serving as non-radiative recombination centers and thus limiting the process of the commercial application.Herein,we propose a redox strategy to dynamically eliminate the defective Pb^(0)and I^(0)generated during device operation using polyoxometalate(POM)as an additive.Benefiting from the reversible W^(5+/6+)redox activity and the structural stability when accepting and donating electrons from perovskite film,POMs play a role of the redox shuttle that oxidizes Pb^(0)into Pb^(2+)and reduces I^(0)into I^(-),consequently inhibiting the formation of Pb^(0)and I^(0)species and reducing the film defects,which benefits the improvement of stability and performance.As a result,the efficiency of carbon-based all-inorganic CsPbI_(2)Br cell is significantly improved to 15.12% and the efficiency of the organic-inorganic hybrid(Cs_(0.05)MA_(0.05)FA_(0.9))Pb(I_(0.93)Br_(0.07))_(3)cell is also increased to 24.20%.More importantly,the target device shows superior stability under air conditions after storage for 1500 h,high temperature after 750 h,and persistent irradiation over200 h,respectively,providing a new method for efficient and stable perovskite solar cells.展开更多
BACKGROUND Preoperative anxiety is a significant concern for patients,as it affects surgical outcomes,satisfaction,and pain perception.Although both anxiety and pain are common in surgical settings,their relationship ...BACKGROUND Preoperative anxiety is a significant concern for patients,as it affects surgical outcomes,satisfaction,and pain perception.Although both anxiety and pain are common in surgical settings,their relationship with personality traits has not been previously investigated in the Lebanese population.AIM To examine the prevalence of preoperative anxiety,pain perception,and personality traits among Lebanese surgical patients,and to assess the associations between these factors.METHODS A descriptive cross-sectional study was conducted between April 2024 and January 2025 across Lebanese hospitals.A total of 392 adult patients were recruited through convenience sampling.Data were collected using a questionnaire that included sociodemographic,clinical,and surgical variables,the Amsterdam Preoperative Anxiety and Information Scale for anxiety,the Visual Analog Scale and Numerical Pain Rating Scale for preoperative pain,and the Ten-Item Personality Inventory for personality traits.Ethical approval was obtained from the Institutional Review Boards of Makassed General Hospital and Hammoud University Medical Center.RESULTS Overall,25%of participants experienced preoperative anxiety,and 34.5%reported moderate pain.Personality assessment showed that the majority of participants had moderate extraversion(84.1%),moderate emotional stability(65.1%),high conscientiousness(61%),high agreeableness(54.1%),and moderate openness(49.2%).High conscientiousness was significantly associated with higher pain perception(P<0.05),while high emotional stability was associated with lower levels of anxiety(P<0.05).No significant association was found between preoperative anxiety and pain(P>0.05).CONCLUSION This study challenges the assumption that preoperative anxiety and pain are directly correlated and highlights the role of personality traits in shaping patient experience.These findings support the potential value of integrating psychological profiling into preoperative care and lay the groundwork for developing personalized interventions to improve patient-centered surgical outcomes.展开更多
Supported metal nanoparticles(NPs)as an important heterogeneous catalyst have been widely applied in various industrial processes.During the catalytic reaction,size of the particles plays an important role in determin...Supported metal nanoparticles(NPs)as an important heterogeneous catalyst have been widely applied in various industrial processes.During the catalytic reaction,size of the particles plays an important role in determining their catalytic performance.Generally,the small particles exhibit superior catalytic activity in comparison with the larger particles because of an increase in lowcoordinated metal atoms on the particle surface that work as active sites,such as edges and corner atoms.However,these small NPs are typically unstable and tend to migrate and coalescence to reduce their surface free energy during the real catalytic processes,particularly in high-temperature reactions.Therefore,a means to fabricate stable small metal NP catalysts with excellent sinter-resistant performance is necessary for maintaining their high catalytic activity.In this study,we have summarized recent advances in stabilizing metal NPs from two aspects including thermodynamic and kinetic strategies.The former mainly involve preparing uniform NPs(with an identical size and homogeneous distribution)in order to restrain Ostwald ripening to achieve stability,while the latter primarily involves fixing metal NPs in some special confinement materials(e.g.,zeolites,mesoporous silica and mesoporous carbons),encapsulating NPs using an oxide-coating film(e.g.,forming core-shell structures),or constructing strong metal-support interactions to improve stability.At the end of this review,we highlight our recent work on the preparation of high-stability metal catalysts via a unique interfacial plasma electrolytic oxidation technology,that is,metal NPs are well embedded in a porous MgO layer that has both high thermal stability and excellent catalytic activity.展开更多
Similar to synchronous generators(SGs),symmetrical short-circuit faults can reduce the stability margin of grid-forming renewable power generation(GFM-RPG),thereby heightening the risk of transient instability.While e...Similar to synchronous generators(SGs),symmetrical short-circuit faults can reduce the stability margin of grid-forming renewable power generation(GFM-RPG),thereby heightening the risk of transient instability.While existing studies primarily examine single-machine infinite-bus systems,this work explores transient stability challenges inherent in paralleled GFM-RPG systems.First,through rigorous mathematical derivation,it establishes that the transient characteristics of paralleled systems can still be effectively characterized by a second-order motion equation.Subsequently,by applying the extended equal area criterion(EEAC)and numerical solutions to differential equations,the study uncovers the governing principles behind the variations in the critical clearing angle(CCA)and critical clearing time(CCT)for the paralleled GFM-RPG system under various operating conditions.Finally,to mitigate potential instability risks,two corrective strategies,namely adaptive damping enhancement and power switching control,are proposed to improve the transient stability of the paralleled system during symmetrical faults.Simulation results confirm the accuracy of the theoretical analysis and demonstrates the effectiveness of the proposed strategy.展开更多
The determination of optimal values for three parameters required in the original particle swarm optimization algorithm is very difficult. It is proposed that two new parameters simulating the harmony search strategy ...The determination of optimal values for three parameters required in the original particle swarm optimization algorithm is very difficult. It is proposed that two new parameters simulating the harmony search strategy can be adopted instead of the three parameters which are required in the original particle swarm optimization algorithm to update the positions of all the particles. The improved particle swarm optimization is used in the location of the critical slip surface of soil slope, and it is found that the improved particle swarm optimization algorithm is insensitive to the two parameters while the original particle swarm optimization algorithm can be sensitive to its three parameters.展开更多
基金supported by the National Natural Science Foundation of China[82003956]the National Key Research and Development Program of China[No.2022YFA1205802]+2 种基金financially supported by Henan Province Health Science and Technology Innovation Youth Talent Project(YQRC2023013 and YQRC2024013)the Key Project of Medical Science and Technology of Henan Province(SBGJ202302072)the Science and Technology Research Project of Henan Province(252102311236).
文摘Single-atom nanozymes(SAzymes)exhibit exceptional catalytic efficiency due to their maximized atom utilization and precisely modulated metalcarrier interactions,which have attracted significant attention in the biomedical field.However,stability issues may impede the clinical translation of SAzymes.This review provides a comprehensive overview of the applications of SAzymes in various biomedical fields,including disease diagnosis(e.g.,biosensors and diagnostic imaging),antitumor therapy(e.g.,photothermal therapy,photodynamic therapy,sonodynamic therapy,and immunotherapy),antimicrobial therapy,and anti-oxidative stress therapy.More importantly,the existing challenges of SAzymes are discussed,such as metal atom clustering and active site loss,ligand bond breakage at high temperature,insufficient environment tolerance,biosecurity risks,and limited catalytic long-term stability.Finally,several innovative strategies to address these stability concerns are proposed—synthesis process optimization(space-limited strategy,coordination site design,bimetallic synergistic strategy,defect engineering strategy,atom stripping-capture),surface modification,and dynamic responsive design—that collectively pave the way for robust,clinically viable SAzymes.
文摘Existing literature has shown that the control force at the nose could cause dynamic instability for controlled projectiles. To lower the adverse impact on the dual-spin projectile with fixed canards under the premise of meeting guidance system requirements, the influence of control moment provided by a motor on the flight stability is analyzed in this paper. Firstly, the effect of the rolling movement on stability is analyzed based on the stability criterion derived using the Hurwitz stability theory. Secondly, the evaluation parameters combining the features of different control periods that could assess the variation of stability features after the motor torque are obtained. These effective formulas are used to indicate that, to reduce the flight instability risks, the stabilized rolling speed of roll speed keeping period should be as small as possible; the variation trend of motor torque during the rolling speed controlling period and the roll angle of the forward body during roll angle switching period are recommended corresponding to the projectile and trajectory characteristics. Moreover,detailed numerical simulations of 155 mm dual-spin projectile are satisfactory agreement with the theoretical results.
基金National Natural Science Foundation of China(Grant No.22005318,22379152)Western Young Scholars Foundations of Chinese Academy of Sciences+4 种基金Lanzhou Youth Science and Technology Talent Innovation Project(Grant No.2023-NQ-86,No.2023-QN-96)Lanzhou Chengguan District Science and Technology Plan Project(Grant No.2023-rc-4,2022-rc-4)Collaborative Innovation Alliance Fund for Young Science and Technology Worker(Grant No.HZJJ23-7)National Nature Science Foundations of Gansu Province(Grant No.21JR11RA020)Fundamental Research Funds for the Central Universities(Grant No.31920220073,31920230128)。
文摘Rechargeable aqueous zinc-ion batteries(AZIBs)exhibit appreciable potential in the domain of electrochemical energy storage.However,there are serious challenges for AZIBs,for instance zinc dendrite growth,hydrogen evolution reaction(HER),and corrosion side reactions.Herein,we propose a surface engineering modification strategy for coating the montmorillonite(MMT)layer onto the surface of the Zn anode to tackle these issues,thereby achieving high cycling stability for rechargeable AZIBs.The results reveal that the MMT layer on the surface of the Zn anode is able to provide ordered zincophilic channels for zinc ions migration,facilitating the reaction kinetics of zinc ions.Density functional theory(DFT)calculations and water contact angle(CA)tests prove that MMT@Zn anode exhibits superior adsorption capacity for Zn^(2+)and better hydrophobicity than the bare Zn anode,thereby achieving excellent cycling stability.Moreover,the MMT@Zn||MMT@Zn symmetric cell holds the stable cycling over 5600 h at 0.5 mA cm^(-2)and 0.125 m A h cm^(-2),even exceeding 1800 h long cycling under harsh conditions of 5 m A cm^(-2)and 1.25 m A h cm^(-2).The MMT@Zn||V_(2)O_(5)full cell reaches over 3000 cycles at 2 A g^(-1)with excellent rate capability.Therefore,this surface engineering modification strategy for enhancing the electrochemical performance of AZIBs represents a promising application.
基金the National Natural Science Foundation of China(NSFC,No.51872172,51972197)Natural Science Foundation of Shandong Province(ZR2019MEM021)Young Scholars Program of Shandong University.
文摘Organic–inorganic hybrid perovskite materials have been focusing more attention in the field of self-powered photodetectors due to their superb photoelectric properties.However,a universal growth approach is required and challenging to realize vertically oriented growth and grain boundary fusion of 2D and 3D perovskite grains to promote ordered carrier transport,which determines superior photoresponse and high stability.Herein,a general thermal-pressed(TP)strategy is designed to solve the above issues,achieving uniaxial orientation and single-grain penetration along the film thickness direction.It constructs the efficient channel for ordered carrier transport between two electrodes.Combining of the improved crystal quality and lower trap-state density,the quasi-2D and 3D perovskite-based self-powered photodetector devices(with/without hole transport layer)all exhibit giant and stable photoresponse in a wide spectrum range and specific wavelength laser.For the MAPbI_(3)-based self-powered photodetectors,the largest R_(λ) value is as high as 0.57 A W^(−1)at 760 nm,which is larger than most reported results.Meanwhile,under laser illumination(532 nm),the FPEA_(2)MA_(4)Pb_(5)I_(16)-based device exhibits a high responsivity(0.4 A W^(−1)) value,which is one of the best results in 2DRP self-powered photodetectors.In addition,fast response,ultralow detection limit,and markedly improved humidity,optical and heat stabilities are clearly demonstrated for these TP-based devices.
基金the National Natural Science Foundation of China (91641203, 51476114, and 91741119)he National Key Research and Development Program of China (2017YFB0103400).
文摘Gasoline compression ignition (GCI) is one of the most promising combustion concepts to maintain low pollutant emissions and high efficiency. However, low load combustion stability and firing in cold-start operations are two major challenges for GCI combustion. Strategies including negative valve overlap (NVO), advanced injection strategies, fuel reforming, and intake preheating have been proposed in order to solve these difficulties;however, the cold start is still an obstacle. The objective of this work is to study effective methods to achieve GCI engine cold start-up. This work combines NVO, in-cylinder fuel reforming, and intake preheating to achieve quick firing under cold-start conditions and the subsequent warmup conditions. The results show that start of injection (SOI) during the intake stroke yields the best fuel economy, and injection during the compression stroke has the potential to extend the low load limit. Furthermore, SOI during the NVO period grants the ability to operate under engine conditions with cold intake air and coolant. With highly reactive products made by in-cylinder fuel reforming and fast heat accumulation in the combustion chamber, the NVO injection strategy is highly appropriate for GCI firing. An additional assisted technical method, such as intake preheating, is required to ignite the first firing cycle for a cold-start process. With the combination of NVO, in-cylinder fuel reforming, and intake preheating, the GCI engine successfully started within five combustion cycles in the experiment. After the firing process, the engine could stably operate without further intake preheating;thus, this method is appropriate for engine cold-start and warm-up.
基金financial support by the National Natural Science Foundation of China (Grant No. U2004212 and 51802012)。
文摘MXenes are under the spotlight due to their versatile physicochemical characteristics. Since their discovery in 2011, significant advancements have been achieved in their synthesis and application sectors. However, the spontaneous oxidation of MXenes, which is critical to its processing and product lifespan, has gotten less attention due to its chemical complexity and poorly understood oxidation mechanism. This perspective focuses on the oxidation stability of MXenes and addresses the most recent advancements in understanding and the possible countermeasures to limit the spontaneous oxidation of MXenes. A section is dedicated to the presently accessible methods for monitoring oxidation, with a discussion on the debatable oxidation mechanism and coherently operating factors that contribute to the complexity of MXenes oxidation. The current potential solutions for mitigating MXenes oxidation and the existing challenges are also discussed with prospects to prolong MXene's shelf-life storage and expand their application scope.
文摘In a previous work(2018,Commun.Theor.Phys.70,795–802),a new compartment model for the spreading of rumors was introduced and analyzed.However,only the local asymptotic stability of this model was discussed.In the present work,we first provide a rigorous mathematical analysis for the global asymptotic stability(GAS)of the above-mentioned rumor spreading model.By constructing suitable Lyapunov candidate functions,we obtain the GAS of a rumor-free(boundary)equilibrium point and a unique rumor-spreading(positive)equilibrium point.After that,we utilize the approach based on the Lyapunov candidate functions to study the GAS of another rumor spreading model with control strategies,which was proposed in(2022,Physica A 606,128157).As an important consequence,the GAS of the rumor spreading model with control strategies is determined fully without resorting to technical hypotheses used in the benchmark work.Lastly,the theoretical findings are supported by a set of illustrative numerical examples.The obtained results not only improve the ones constructed in the two abovementioned benchmark papers but also can be extended to study the global dynamics of other rumor propagation models in the context of both integer-order and fractional-order derivatives.
文摘This paper considers the problem of simultaneous estimation of the system states and the strategy of commutation for a larger class of nonlinear switched systems.First,a hybrid high gain observer is considered to get the exact estimation of the continuous states where the strategy of switching is previously known.Then,an extension to a larger class of nonlinear hybrid systems with arbitrary switching is made.Stability analysis is widely discussed for the two cases to provide a finite-time convergence of the estimation errors.The effectiveness of the proposed hybrid high gain observer has been proved by applying it to a quadruple tank process.
基金financially supported by National Natural Science Foundation of China(Nos.22122202,22072051,21972051)。
文摘Water splitting with proton exchange membrane water electrolyzers(PEMWE)is regarded as a promising pathway for sustainable hydrogen conversion.Additionally,oxygen evolution reaction(OER)is considered as the dominant factor during the whole process due to the sluggish kinetics.Among the catalysts,Rubased catalysts draw special attention because of their excellent activity and relatively low price.However,the limited stability impedes their further commercialization and tremendous efforts have been devoted to overcome this challenge.This review firstly introduces the basic mechanisms of OER.Then the evaluation protocols and techniques to investigate the stability of Ru-based catalysts are summarized.A detailed elucidation of the possible degradation mechanisms is also critically analyzed.Furthermore,effective strategies to design durable Ru-based catalysts for acidic OER are discussed.Such as heteroatom doping,phase and facet engineering,heterostructure building and support optimization.Finally,promises,perspectives and challenges in developing highly durable Ru-based catalysts for acidic OER are outlined.
基金Project supported by the Natural Science Foundation of Zhejiang Province,China(Grant No.LY20G010004)the Program of Humanities and Social Science of Education Ministry of China(Grant No.20YJA630008)+1 种基金the National Key Research and Development Program of China–Traffic Modeling,Surveillance and Control with Connected&Automated Vehicles(Grant No.2017YFE9134700)the K.C.Wong Magna Fund in Ningbo University,China。
文摘An extended car-following model with multiple delays is constructed to describe driver's driving behavior.Through stability analysis,the stability condition of this uncontrolled model is given.To dampen the negative impact of the driver's multiple delays(i.e.,stability condition is not satisfied),a novel control strategy is proposed to assist the driver in adjusting vehicle operation.The control strategy consists of two parts:the design of control term as well as the design of the parameters in the term.Bifurcation analysis is performed to illustrate the necessity of the design of parameters in control terms.In the course of the design of parameters in the control term,we improve the definite integral stability method to reduce the iterations by incorporating the characteristics of bifurcation,which can determine the appropriate parameters in the control terms more quickly.Finally,in the case study,we validate the control strategy by utilizing measured data and configuring scenario,which is closer to the actual traffic.The results of validation show that the control strategy can effectively stabilize the unstable traffic flow caused by driver's delays.
文摘In this paper, transient stability analysis was focused on Hu-Liao HVDC and AC parallel transmission system. The Hu-Liao HVDC project was introduced;Simulation method and mathematic models of AC and DC systems were stu-died as well as corresponding regulators and controllers. The dynamic performance and the interaction between AC and DC systems during serious disturbance were researched by detail time-domain simulation. Comparison was also made under different operation schemes. The research will bring important and significant reference for further operation and stability control of Hu-Liao HVDC and AC system.
文摘With the continuous growth of China's economy,financial opening to the outside world has become one of the important means to promote economic development.However,with the continuous acceleration of capital flow,the problem of balance in and out is becoming increasingly prominent.Taking China's financial opening to the outside world as the research object,this paper discusses how China strategically achieves the balance of entry and exit in the field of financial opening to the outside world,and the impact of this balance.Through the quantitative analysis of China's financial opening to the outside world and foreign capital flows,it is found that China needs to strengthen the management of capital items and optimize the structure of capital flows in the process of financial opening to the outside world,to achieve the balance of financial flows in and out.As for the impact of the balance of access and access,the analysis of the impact mechanism shows that the financial opening and access and balance can improve the stability of the financial market,provide sufficient liquidity for the healthy development of the financial market,and alleviate financial risks.Such a strategy is of great practical significance for promoting the sustained and healthy development of China's economy.Therefore,based on the actual situation of China,this paper puts forward some relevant strategy suggestions to guide the practical operation of China's financial opening up.
基金financial support provided by the National Natural Science Foundation of China(62374105,62304124,52472259,62204098,22179051)the Special Fund of Taishan Scholar Program of Shandong Province(tsqnz20221141)。
文摘Persistent illumination inevitably leads to the formation of Pb^(0)and I^(0)species in perovskite film,serving as non-radiative recombination centers and thus limiting the process of the commercial application.Herein,we propose a redox strategy to dynamically eliminate the defective Pb^(0)and I^(0)generated during device operation using polyoxometalate(POM)as an additive.Benefiting from the reversible W^(5+/6+)redox activity and the structural stability when accepting and donating electrons from perovskite film,POMs play a role of the redox shuttle that oxidizes Pb^(0)into Pb^(2+)and reduces I^(0)into I^(-),consequently inhibiting the formation of Pb^(0)and I^(0)species and reducing the film defects,which benefits the improvement of stability and performance.As a result,the efficiency of carbon-based all-inorganic CsPbI_(2)Br cell is significantly improved to 15.12% and the efficiency of the organic-inorganic hybrid(Cs_(0.05)MA_(0.05)FA_(0.9))Pb(I_(0.93)Br_(0.07))_(3)cell is also increased to 24.20%.More importantly,the target device shows superior stability under air conditions after storage for 1500 h,high temperature after 750 h,and persistent irradiation over200 h,respectively,providing a new method for efficient and stable perovskite solar cells.
文摘BACKGROUND Preoperative anxiety is a significant concern for patients,as it affects surgical outcomes,satisfaction,and pain perception.Although both anxiety and pain are common in surgical settings,their relationship with personality traits has not been previously investigated in the Lebanese population.AIM To examine the prevalence of preoperative anxiety,pain perception,and personality traits among Lebanese surgical patients,and to assess the associations between these factors.METHODS A descriptive cross-sectional study was conducted between April 2024 and January 2025 across Lebanese hospitals.A total of 392 adult patients were recruited through convenience sampling.Data were collected using a questionnaire that included sociodemographic,clinical,and surgical variables,the Amsterdam Preoperative Anxiety and Information Scale for anxiety,the Visual Analog Scale and Numerical Pain Rating Scale for preoperative pain,and the Ten-Item Personality Inventory for personality traits.Ethical approval was obtained from the Institutional Review Boards of Makassed General Hospital and Hammoud University Medical Center.RESULTS Overall,25%of participants experienced preoperative anxiety,and 34.5%reported moderate pain.Personality assessment showed that the majority of participants had moderate extraversion(84.1%),moderate emotional stability(65.1%),high conscientiousness(61%),high agreeableness(54.1%),and moderate openness(49.2%).High conscientiousness was significantly associated with higher pain perception(P<0.05),while high emotional stability was associated with lower levels of anxiety(P<0.05).No significant association was found between preoperative anxiety and pain(P>0.05).CONCLUSION This study challenges the assumption that preoperative anxiety and pain are directly correlated and highlights the role of personality traits in shaping patient experience.These findings support the potential value of integrating psychological profiling into preoperative care and lay the groundwork for developing personalized interventions to improve patient-centered surgical outcomes.
基金financially supported by the National Natural Science Foundation of China (Nos.51601032, 51971059,5197010432)the Fundamental Research Funds for the Central Universities (Nos.N170204015,N180204014)the Provincial Science and Technology Project/Doctor Start Fund (No. 20170520385).
文摘Supported metal nanoparticles(NPs)as an important heterogeneous catalyst have been widely applied in various industrial processes.During the catalytic reaction,size of the particles plays an important role in determining their catalytic performance.Generally,the small particles exhibit superior catalytic activity in comparison with the larger particles because of an increase in lowcoordinated metal atoms on the particle surface that work as active sites,such as edges and corner atoms.However,these small NPs are typically unstable and tend to migrate and coalescence to reduce their surface free energy during the real catalytic processes,particularly in high-temperature reactions.Therefore,a means to fabricate stable small metal NP catalysts with excellent sinter-resistant performance is necessary for maintaining their high catalytic activity.In this study,we have summarized recent advances in stabilizing metal NPs from two aspects including thermodynamic and kinetic strategies.The former mainly involve preparing uniform NPs(with an identical size and homogeneous distribution)in order to restrain Ostwald ripening to achieve stability,while the latter primarily involves fixing metal NPs in some special confinement materials(e.g.,zeolites,mesoporous silica and mesoporous carbons),encapsulating NPs using an oxide-coating film(e.g.,forming core-shell structures),or constructing strong metal-support interactions to improve stability.At the end of this review,we highlight our recent work on the preparation of high-stability metal catalysts via a unique interfacial plasma electrolytic oxidation technology,that is,metal NPs are well embedded in a porous MgO layer that has both high thermal stability and excellent catalytic activity.
基金supported by Joint Research Fund in Smart Grid(No.U1966208)under cooperative agreement between the National Natural Science Foundation of China and State Grid Corporation of China.
文摘Similar to synchronous generators(SGs),symmetrical short-circuit faults can reduce the stability margin of grid-forming renewable power generation(GFM-RPG),thereby heightening the risk of transient instability.While existing studies primarily examine single-machine infinite-bus systems,this work explores transient stability challenges inherent in paralleled GFM-RPG systems.First,through rigorous mathematical derivation,it establishes that the transient characteristics of paralleled systems can still be effectively characterized by a second-order motion equation.Subsequently,by applying the extended equal area criterion(EEAC)and numerical solutions to differential equations,the study uncovers the governing principles behind the variations in the critical clearing angle(CCA)and critical clearing time(CCT)for the paralleled GFM-RPG system under various operating conditions.Finally,to mitigate potential instability risks,two corrective strategies,namely adaptive damping enhancement and power switching control,are proposed to improve the transient stability of the paralleled system during symmetrical faults.Simulation results confirm the accuracy of the theoretical analysis and demonstrates the effectiveness of the proposed strategy.
基金supported by the National Natural Science Foundation of China (Grant No. 51008167)S&T Plan Project (Grant No. J10LE07) from Shandong Provincial Education Departmentthe Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20103721120001)
文摘The determination of optimal values for three parameters required in the original particle swarm optimization algorithm is very difficult. It is proposed that two new parameters simulating the harmony search strategy can be adopted instead of the three parameters which are required in the original particle swarm optimization algorithm to update the positions of all the particles. The improved particle swarm optimization is used in the location of the critical slip surface of soil slope, and it is found that the improved particle swarm optimization algorithm is insensitive to the two parameters while the original particle swarm optimization algorithm can be sensitive to its three parameters.
