This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological ...This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.展开更多
An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and coll...An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and collision avoidance.However,inherent nonlinearities and uncertainties present in practical control systems contribute to the challenge of achieving precise control performance.Based on the IT-2 Takagi-Sugeno Fuzzy Model(T-SFM),the fuzzy control approach can offer a more effective solution for NMASs facing uncertainties.Unlike existing control methods for NMASs,the Formation and Containment(F-and-C)control problem with collision avoidance capability under uncertainties based on the IT-2 T-SFM is discussed for the first time.Moreover,an IT-2 fuzzy tracking control approach is proposed to solve the formation task for leaders in NMASs without requiring communication.This control scheme makes the design process of the IT-2 fuzzy Formation Controller(FC)more straightforward and effective.According to the communication interaction protocol,the IT-2 Containment Controller(CC)design approach is proposed for followers to ensure convergence into the region defined by the leaders.Leveraging the IT-2 T-SFM representation,the analysis methods developed for linear Multi-Agent Systems(MASs)are successfully extended to perform containment analysis without requiring the additional assumptions imposed in existing research.Notably,the IT-2 fuzzy tracking controller can also be applied in collision avoidance situations to track the desired trajectories calculated by the avoidance algorithm under the Artificial Potential Field(APF).Benefiting from the combination of vortex and source APFs,the leaders can properly adjust the system dynamics to prevent potential collision risk.Integrating the fuzzy theory and APFs avoidance algorithm,an IT-2 fuzzy controller design approach is proposed to achieve the F-and-C purposewhile ensuring collision avoidance capability.Finally,amulti-ship simulation is conducted to validate the feasibility and effectiveness of the designed IT-2 fuzzy controller.展开更多
3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,ex...3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,excellent pseudocapacitance,and fast charging capabilities.However,searching for eco-friendly aqueous Ti_(3)C_(2)T_(x) MXene-based inks without additives and preventing severe restack of MXene nanosheets in high-concentration inks are significantly challenging.This study develops an additive-free,highly printable,viscosity adjustable,and environmentally friendly MXene/carbon nanotube(CNT)hybrid aqueous inks,in which the CNT can not only adjust the viscosity of Ti_(3)C_(2)T_(x) MXene inks but also widen the interlayer spacing of adjacent Ti_(3)C_(2)T_(x) MXene nanosheets effectively.The optimized MXene/CNT composite inks are successfully adopted to construct various configurations of MSCs with remarkable shape fidelity and geometric accuracy,together with enhanced surface area accessibility for electrons and ions diffusion.As a result,the constructed interdigital symmetrical MSCs demonstrate outstanding areal capacitance(1249.3 mF cm^(-2)),superior energy density(111μWh cm^(-2) at 0.4mWcm^(-2)),and high power density(8mWcm^(-2) at 47.1μWh cm^(-2)).Furthermore,a self-powered modular system of solar cells integrated with MXene/CNT-MSCs and pressure sensors is successfully tailored,simultaneously achieving efficient solar energy collection and real-time human activities monitoring.This work offers insight into the understanding of the role of CNTs in MXene/CNT ink.Moreover,it provides a new approach for preparing environmentally friendly MXene-based inks for the 3D printing of high-performance MSCs,contributing to the development of miniaturized,flexible,and self-powered printable electronic microsystems.展开更多
It has been well established that carbon dioxide(CO_(2))is one of the main greenhouse gasses and a leading driver of climate change.The chemical conversion of CO_(2) to substitute natural gas(SNG)in the presence of re...It has been well established that carbon dioxide(CO_(2))is one of the main greenhouse gasses and a leading driver of climate change.The chemical conversion of CO_(2) to substitute natural gas(SNG)in the presence of renewable hydrogen is one of the most promising solutions by a well-known process called CO_(2) methanation.There have been comprehensive efforts in developing effective and efficient CO_(2) methanation catalytic systems.However,the choice of competitive and stable catalysts is still a monumental obstruction and a great challenge towards the commercialization and industrialization of CO_(2) methanation.It is necessary to emphasize the critical understandings of intrinsic and extrinsic interactions of catalyst components(active metal,support,promoter,etc.)for enhanced catalytic performance and stability during CO_(2) methanation.This study reviews the up-to-date developments on CO_(2) methanation catalysts and the optimal synergistic relationship between active metals,support,and promoters during the catalytic activity.The existing catalysts and their novel properties for enhanced CO_(2) methanation were elucidated using the state-of-the-art experimental and theoretical techniques.The selection of an appropriate synthesis method,catalytic activity for CO_(2) methanation,deactivation of the catalysts,and reaction mechanisms studies,have been explicitly compared and explained.Therefore,future efforts should be directed towards the sustainable developments of catalytic configurations for successful industrial applications of CO_(2) utilization to SNG using CO_(2) methanation.展开更多
The robust stability test of time-delay systems with interval parameters can be concluded into the robust stability of the interval quasipolynomials. It has been revealed that the robust stability of the quasipolynomi...The robust stability test of time-delay systems with interval parameters can be concluded into the robust stability of the interval quasipolynomials. It has been revealed that the robust stability of the quasipolynomials depends on that of their edge polynomials. This paper transforms the interval quasipolynomials into two-dimensional （2-D） interval polynomials （2-D s-z hybrid polynomials）, proves that the robust stability of interval 2-D polynomials are sufficient for the stability of given quasipolynomials. Thus, the stability test of interval quasipolynomials can be completed in 2-D s-z domain instead of classical 1-D s domain. The 2-D s-z hybrid polynomials should have different forms under the time delay properties of given quasipolynomials. The stability test proposed by the paper constructs an edge test set from Kharitonov vertex polynomials to reduce the number of testing edge polynomials. The 2-D algebraic tests are provided for the stability test of vertex 2-D polynomials and edge 2-D polynomials family. To verify the results of the paper to be correct and valid, the simulations based on proposed results and comparison with other presented results are given.展开更多
A new adaptive Type-2 （T2） fuzzy controller was developed and its potential performance advantage over adaptive Type-1 （T1） fuzzy control was also quantified in computer simulation. Base on the Lyapunov method, th...A new adaptive Type-2 （T2） fuzzy controller was developed and its potential performance advantage over adaptive Type-1 （T1） fuzzy control was also quantified in computer simulation. Base on the Lyapunov method, the adaptive laws with guaranteed system stability and convergence were developed. The controller updates its parameters online using the laws to control a system and tracks its output command trajectory. The simulation study involving the popular inverted pendulum control problem shows theoretically predicted system stability and good tracking performance. And the comparison simulation experiments subjected to white noige or step disturbance indicate that the T2 controller is better than the T1 controller by 0--18%, depending on the experiment condition and performance measure.展开更多
Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to ...Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to address the global energy and environmental crisis caused by increased CO2 emission.We illustrate the recent progress in this field.Here,we first review the natural CO2 fixation pathways for an in-depth understanding of the biological CO2 transformation strategy and why a sustainable feed of reducing power is important.Second,we review the recent progress in the construction of abiotic-biological hybrid systems for CO2 transformation from two aspects:(i)microbial electrosynthesis systems that utilize electricity to support whole-cell biological CO2 conversion to products of interest and(ii)photosynthetic semiconductor biohybrid systems that integrate semiconductor nanomaterials with CO2-fixing microorganisms to harness solar energy for biological CO2 transformation.Lastly,we discuss potential approaches for further improvement of abiotic-biological hybrid systems.展开更多
The recent emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)caused serious harm to human health and struck a blow to global economic development.Research on SARS-CoV-2 has greatly benefited from...The recent emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)caused serious harm to human health and struck a blow to global economic development.Research on SARS-CoV-2 has greatly benefited from the use of reverse genetics systems,which have been established to artificially manipulate the viral genome,generating recombinant and reporter infectious viruses or biosafety level 2(BSL-2)-adapted non-infectious replicons with desired modifications.These tools have been instrumental in studying the molecular biological characteristics of the virus,investigating antiviral therapeutics,and facilitating the development of attenuated vaccine candidates.Here,we review the construction strategies,development,and applications of reverse genetics systems for SARS-CoV-2,which may be applied to other CoVs as well.展开更多
This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constra...This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl2/GH2 control problem can be solved less conservatively using computationally tractable algorithms developed in the paper.展开更多
Wastewater-based epidemiology(WBE)has emerged as an effective environmental surveillance tool in monitoring fecal-oral pathogen infections within a community.Congruently,SARS-Co V-2,the etiologic agent of COVID-19,has...Wastewater-based epidemiology(WBE)has emerged as an effective environmental surveillance tool in monitoring fecal-oral pathogen infections within a community.Congruently,SARS-Co V-2,the etiologic agent of COVID-19,has been demonstrated to infect the gastrointestinal tissues,and be shed in feces.In the present study,SARS-Co V-2 RNA was concentrated from wastewater,sludge,surface water,ground water,sediment,and soil samples of municipal and hospital wastewater systems and related environments in Wuhan during the COVID-19 middle and low risk periods,and the viral RNA copies quantified using reverse transcription quantitative polymerase chain reaction(RT-q PCR).From the findings of this study,during the middle risk period,one influent sample and three secondary effluents collected from waste water treatment plant 2,as well as two samples from Jinyintan Hospital wastewater system influent were SARS-Co V-2 RNA positive.One sludge sample collected from Guanggu Branch of Tongji Hospital,which was obtained during the low risk period,was also positive for SARS-Co V-2 RNA.These study findings demonstrate the significance of WBE in continuous surveillance of SARS-Co V-2 at the community level,even when the COVID-19 prevalence is low.Overall,this study can be used as an important reference for contingency management of wastewater treatment plants and COVID-19 prevention and control departments of Wuhan.展开更多
This paper investigates L2-gain analysis and anti-windup compensation gains design for a class of discrete-time switched systems with saturating actuators and L2 bounded disturbances by using the switched Lyapunov fun...This paper investigates L2-gain analysis and anti-windup compensation gains design for a class of discrete-time switched systems with saturating actuators and L2 bounded disturbances by using the switched Lyapunov function approach.For a given set of anti-windup compensation gains,we firstly give a sufficient condition on tolerable disturbances under which the state trajectory starting from the origin will remain inside a bounded set for the corresponding closed-loop switched system subject to L2 bounded disturbances.Then,the upper bound on the restricted L2-gain is obtained over the set of tolerable disturbances.Furthermore,the antiwindup compensation gains aiming to determine the largest disturbance tolerance level and the smallest upper bound of the restricted L2-gain are presented by solving a convex optimization problem with linear matrix inequality(LMI) constraints.A numerical example is given to illustrate the effectiveness of the proposed design method.展开更多
This paper addresses an infinite horizon distributed H2/H∞ filtering for discrete-time systems under conditions of bounded power and white stochastic signals. The filter algorithm is designed by computing a pair of g...This paper addresses an infinite horizon distributed H2/H∞ filtering for discrete-time systems under conditions of bounded power and white stochastic signals. The filter algorithm is designed by computing a pair of gains namely the estimator and the coupling. Herein, we implement a filter to estimate unknown parameters such that the closed-loop multi-sensor accomplishes the desired performances of the proposed H2 and H∞ schemes over a finite horizon. A switched strategy is implemented to switch between the states once the operation conditions have changed due to disturbances. It is shown that the stability of the overall filtering-error system with H2/H∞ performance can be established if a piecewise-quadratic Lyapunov function is properly constructed. A simulation example is given to show the effectiveness of the proposed approach.展开更多
The next generation of advanced light sources requires photons with large average flux and high brightness,which needs advanced electron gun matched with excellent photocathode materials. K_(2)CsSb photocathode has th...The next generation of advanced light sources requires photons with large average flux and high brightness,which needs advanced electron gun matched with excellent photocathode materials. K_(2)CsSb photocathode has the advantages of high quantum efficiency, long lifetime and instantaneous response. This study introduces the design of a set of K_(2)CsSb photocathode preparation systems and detailed preparation process of K_(2)CsSb photocathodes, including sequential deposition process and co-deposition process, and finally develops a K_(2)CsSb photocathode. The influence of laser power on the quantum efficiency is also investigated.展开更多
In this paper, an adaptive type-2 fuzzy sliding mode control to tolerate actuator faults of unknown nonlinear systems with external disturbances is presented. Based on a redundant actuation structure, a novel type-2 a...In this paper, an adaptive type-2 fuzzy sliding mode control to tolerate actuator faults of unknown nonlinear systems with external disturbances is presented. Based on a redundant actuation structure, a novel type-2 adaptive fuzzy fault tolerant control scheme is proposed using sliding mode control. Two adaptive type-2 fuzzy logic systems are used to approximate the unknown functions, whose adaptation laws are deduced from the stability analysis. The proposed approach allows to ensure good tracking performance despite the presence of actuator failures and external disturbances, as illustrated through a simulation example.展开更多
This paper deals with the iterative learning control （ILC） design for multiple-input multiple-output （MIMO）,time-delay systems （TDS）.Two feedback ILC schemes are considered using the so-called two-dimensional ...This paper deals with the iterative learning control （ILC） design for multiple-input multiple-output （MIMO）,time-delay systems （TDS）.Two feedback ILC schemes are considered using the so-called two-dimensional （2D） analysis approach.It shows that continuous-discrete 2D Roesser systems can be developed to describe the entire learning dynamics of both ILC schemes,based on which necessary and sufficient conditions for their stability can be provided.A numerical example is included to validate the theoretical analysis.展开更多
Molybdenum disulfide (MoS_(2)) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is considerably limi...Molybdenum disulfide (MoS_(2)) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is considerably limited due to its inert basal planes. Here, through the combination of theory and experiment, we propose that doping Ni in MoS_(2) as catalyst can make it have excellent catalytic activity in different reaction systems. In the EY/TEOA system, the maximum hydrogen production rate of EY/Ni-Mo-S is 2.72 times higher than that of pure EY, which confirms the strong hydrogen evolution activity of Ni-Mo-S nanosheets as catalysts. In the lactic acid and Na_(2)S/Na_(2)SO_(3) systems, when Ni-Mo-S is used as co-catalyst to compound with ZnIn_(2)S_(4) (termed as Ni-Mo-S/ZnIn_(2)S_(4)), the maximum hydrogen evolution rates in the two systems are 5.28 and 2.33 times higher than those of pure ZnIn_(2)S_(4), respectively. The difference in HER enhancement is because different systems lead to different sources of protons, thus affecting hydrogen evolution activity. Theoretically, we further demonstrate that the Ni-Mo-S nanosheets have a narrower band gap than MoS_(2), which is conducive to the rapid transfer of charge carriers and thus result in multi-photocatalytic reaction systems with excellent activity. The proposed atomic doping strategy provides a simple and promising approach for the design of photocatalysts with high activity and stability in multi-reaction systems.展开更多
The molten mixtures of alkali metal fluorides and aluminum fluoride are applied as aluminum electrolytes or brazing fluxes.However,the presence of Al2F-7^-in such molten systems is disputed.In the present study,MF-AlF...The molten mixtures of alkali metal fluorides and aluminum fluoride are applied as aluminum electrolytes or brazing fluxes.However,the presence of Al2F-7^-in such molten systems is disputed.In the present study,MF-AlF3(M=K,Cs)systems with molar ratios<1 were studied by in-situ Raman spectroscopy and molecular simulation.The results show that,in addition to AlF6^(3-),AlF5^(2-),and AlF4^-,the systems also contained Al2F-7^-.The characteristic bands in the Raman spectra belonging to Al2F-7^-were located at about 225 cm^-1,315 cm^-1,479 cm^-1,and 720 cm^-1.There are two possible structures of Al2F-7^-,which belong to the D3d and D3hpoint groups.Both of these structures are linear,and their single-point energies were found to differ by only 0.31 kcal/mol.展开更多
We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of groundstate pairwise entanglement for the four-qubit model by identifying a Z2 symmetry. Although the entanglements cannot...We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of groundstate pairwise entanglement for the four-qubit model by identifying a Z2 symmetry. Although the entanglements cannot identify the critical point of the system, the mean entanglement of the nearest-neighbor qubits really does, namely, it reaches a maximum at the critical point.展开更多
This paper is concerned with the problem of stabilization of the Roesser type discrete-time nonlinear 2-D system that plays an important role in many practical applications. First, a discrete-time 2-D T-S fuzzy model ...This paper is concerned with the problem of stabilization of the Roesser type discrete-time nonlinear 2-D system that plays an important role in many practical applications. First, a discrete-time 2-D T-S fuzzy model is proposed to represent the underlying nonlinear 2-D system. Second, new quadratic stabilization conditions are proposed by applying relaxed quadratic stabilization technique for 2-D case. Third, for sake of further reducing conservatism, new non-quadratic stabilization conditions are also proposed by applying a new parameter-dependent Lyapunov function, matrix transformation technique, and relaxed technique for the underlying discrete-time 2-D T-S fuzzy system. Finally, a numerical example is provided to illustrate the effectiveness of the proposed results.展开更多
文摘This study introduces a Transformer-based multimodal fusion framework for simulating multiphase flow and heat transfer in carbon dioxide(CO_(2))–water enhanced geothermal systems(EGS).The model integrates geological parameters,thermal gradients,and control schedules to enable fast and accurate prediction of complex reservoir dynamics.The main contributions are:(i)development of a workflow that couples physics-based reservoir simulation with a Transformer neural network architecture,(ii)design of physics-guided loss functions to enforce conservation of mass and energy,(iii)application of the surrogate model to closed-loop optimization using a differential evolution(DE)algorithm,and(iv)incorporation of economic performance metrics,such as net present value(NPV),into decision support.The proposed framework achieves root mean square error(RMSE)of 3–5%,mean absolute error(MAE)below 4%,and coefficients of determination greater than 0.95 across multiple prediction targets,including production rates,pressure distributions,and temperature fields.When compared with recurrent neural network(RNN)baselines such as gated recurrent units(GRU)and long short-term memory networks(LSTM),as well as a physics-informed reduced-order model,the Transformer-based approach demonstrates superior accuracy and computational efficiency.Optimization experiments further show a 15–20%improvement in NPV,highlighting the framework’s potential for real-time forecasting,optimization,and decision-making in geothermal reservoir engineering.
基金founded by the National Science and Technology Council of the Republic of China under contract NSTC113-2221-E-019-032.
文摘An Interval Type-2(IT-2)fuzzy controller design approach is proposed in this research to simultaneously achievemultiple control objectives inNonlinearMulti-Agent Systems(NMASs),including formation,containment,and collision avoidance.However,inherent nonlinearities and uncertainties present in practical control systems contribute to the challenge of achieving precise control performance.Based on the IT-2 Takagi-Sugeno Fuzzy Model(T-SFM),the fuzzy control approach can offer a more effective solution for NMASs facing uncertainties.Unlike existing control methods for NMASs,the Formation and Containment(F-and-C)control problem with collision avoidance capability under uncertainties based on the IT-2 T-SFM is discussed for the first time.Moreover,an IT-2 fuzzy tracking control approach is proposed to solve the formation task for leaders in NMASs without requiring communication.This control scheme makes the design process of the IT-2 fuzzy Formation Controller(FC)more straightforward and effective.According to the communication interaction protocol,the IT-2 Containment Controller(CC)design approach is proposed for followers to ensure convergence into the region defined by the leaders.Leveraging the IT-2 T-SFM representation,the analysis methods developed for linear Multi-Agent Systems(MASs)are successfully extended to perform containment analysis without requiring the additional assumptions imposed in existing research.Notably,the IT-2 fuzzy tracking controller can also be applied in collision avoidance situations to track the desired trajectories calculated by the avoidance algorithm under the Artificial Potential Field(APF).Benefiting from the combination of vortex and source APFs,the leaders can properly adjust the system dynamics to prevent potential collision risk.Integrating the fuzzy theory and APFs avoidance algorithm,an IT-2 fuzzy controller design approach is proposed to achieve the F-and-C purposewhile ensuring collision avoidance capability.Finally,amulti-ship simulation is conducted to validate the feasibility and effectiveness of the designed IT-2 fuzzy controller.
基金supported by the National Natural Science Foundation of China(52174247,52477213,52401244 and 22302066)Science and Technology Innovation Program of Hunan Province(No.2022RC1088)+2 种基金Natural Science Foundation of Hunan Province(2023JJ40255)Zhejiang Provincial Natural Science Foundation of China(No.LQ24B020005)Scientific Research Foundation of Hunan Provincial Education Department(22B0599 and 23A0442).
文摘3D-printed Ti_(3)C_(2)T_(x) MXene-based interdigital micro-supercapacitors(MSCs)have great potential as energy supply devices in the field of microelectronics due to their short ion diffusion path,high conductivity,excellent pseudocapacitance,and fast charging capabilities.However,searching for eco-friendly aqueous Ti_(3)C_(2)T_(x) MXene-based inks without additives and preventing severe restack of MXene nanosheets in high-concentration inks are significantly challenging.This study develops an additive-free,highly printable,viscosity adjustable,and environmentally friendly MXene/carbon nanotube(CNT)hybrid aqueous inks,in which the CNT can not only adjust the viscosity of Ti_(3)C_(2)T_(x) MXene inks but also widen the interlayer spacing of adjacent Ti_(3)C_(2)T_(x) MXene nanosheets effectively.The optimized MXene/CNT composite inks are successfully adopted to construct various configurations of MSCs with remarkable shape fidelity and geometric accuracy,together with enhanced surface area accessibility for electrons and ions diffusion.As a result,the constructed interdigital symmetrical MSCs demonstrate outstanding areal capacitance(1249.3 mF cm^(-2)),superior energy density(111μWh cm^(-2) at 0.4mWcm^(-2)),and high power density(8mWcm^(-2) at 47.1μWh cm^(-2)).Furthermore,a self-powered modular system of solar cells integrated with MXene/CNT-MSCs and pressure sensors is successfully tailored,simultaneously achieving efficient solar energy collection and real-time human activities monitoring.This work offers insight into the understanding of the role of CNTs in MXene/CNT ink.Moreover,it provides a new approach for preparing environmentally friendly MXene-based inks for the 3D printing of high-performance MSCs,contributing to the development of miniaturized,flexible,and self-powered printable electronic microsystems.
基金This research work was made possible by a Transdisciplinary Research Grant from Universiti Teknologi Malaysia(Grant No.06G52 and 06G53).
文摘It has been well established that carbon dioxide(CO_(2))is one of the main greenhouse gasses and a leading driver of climate change.The chemical conversion of CO_(2) to substitute natural gas(SNG)in the presence of renewable hydrogen is one of the most promising solutions by a well-known process called CO_(2) methanation.There have been comprehensive efforts in developing effective and efficient CO_(2) methanation catalytic systems.However,the choice of competitive and stable catalysts is still a monumental obstruction and a great challenge towards the commercialization and industrialization of CO_(2) methanation.It is necessary to emphasize the critical understandings of intrinsic and extrinsic interactions of catalyst components(active metal,support,promoter,etc.)for enhanced catalytic performance and stability during CO_(2) methanation.This study reviews the up-to-date developments on CO_(2) methanation catalysts and the optimal synergistic relationship between active metals,support,and promoters during the catalytic activity.The existing catalysts and their novel properties for enhanced CO_(2) methanation were elucidated using the state-of-the-art experimental and theoretical techniques.The selection of an appropriate synthesis method,catalytic activity for CO_(2) methanation,deactivation of the catalysts,and reaction mechanisms studies,have been explicitly compared and explained.Therefore,future efforts should be directed towards the sustainable developments of catalytic configurations for successful industrial applications of CO_(2) utilization to SNG using CO_(2) methanation.
基金This project was supported by the National Science Foundation of China (60572093).
文摘The robust stability test of time-delay systems with interval parameters can be concluded into the robust stability of the interval quasipolynomials. It has been revealed that the robust stability of the quasipolynomials depends on that of their edge polynomials. This paper transforms the interval quasipolynomials into two-dimensional （2-D） interval polynomials （2-D s-z hybrid polynomials）, proves that the robust stability of interval 2-D polynomials are sufficient for the stability of given quasipolynomials. Thus, the stability test of interval quasipolynomials can be completed in 2-D s-z domain instead of classical 1-D s domain. The 2-D s-z hybrid polynomials should have different forms under the time delay properties of given quasipolynomials. The stability test proposed by the paper constructs an edge test set from Kharitonov vertex polynomials to reduce the number of testing edge polynomials. The 2-D algebraic tests are provided for the stability test of vertex 2-D polynomials and edge 2-D polynomials family. To verify the results of the paper to be correct and valid, the simulations based on proposed results and comparison with other presented results are given.
基金Project(51005253) supported by the National Natural Science Foundation of ChinaProject(2007AA04Z344) supported by the National High Technology Research and Development Program of China
文摘A new adaptive Type-2 （T2） fuzzy controller was developed and its potential performance advantage over adaptive Type-1 （T1） fuzzy control was also quantified in computer simulation. Base on the Lyapunov method, the adaptive laws with guaranteed system stability and convergence were developed. The controller updates its parameters online using the laws to control a system and tracks its output command trajectory. The simulation study involving the popular inverted pendulum control problem shows theoretically predicted system stability and good tracking performance. And the comparison simulation experiments subjected to white noige or step disturbance indicate that the T2 controller is better than the T1 controller by 0--18%, depending on the experiment condition and performance measure.
文摘Abiotic-biological hybrid systems that combine the advantages of abiotic catalysis and biotransformation for the conversion of carbon dioxide(CO2)to value-added chemicals and fuels have emerged as an appealing way to address the global energy and environmental crisis caused by increased CO2 emission.We illustrate the recent progress in this field.Here,we first review the natural CO2 fixation pathways for an in-depth understanding of the biological CO2 transformation strategy and why a sustainable feed of reducing power is important.Second,we review the recent progress in the construction of abiotic-biological hybrid systems for CO2 transformation from two aspects:(i)microbial electrosynthesis systems that utilize electricity to support whole-cell biological CO2 conversion to products of interest and(ii)photosynthetic semiconductor biohybrid systems that integrate semiconductor nanomaterials with CO2-fixing microorganisms to harness solar energy for biological CO2 transformation.Lastly,we discuss potential approaches for further improvement of abiotic-biological hybrid systems.
基金the Major Research Plan of the National Natural Science Foundation of China(92269105)the Zhejiang Provincial Natural Science Foundation(LZ22C180002).
文摘The recent emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)caused serious harm to human health and struck a blow to global economic development.Research on SARS-CoV-2 has greatly benefited from the use of reverse genetics systems,which have been established to artificially manipulate the viral genome,generating recombinant and reporter infectious viruses or biosafety level 2(BSL-2)-adapted non-infectious replicons with desired modifications.These tools have been instrumental in studying the molecular biological characteristics of the virus,investigating antiviral therapeutics,and facilitating the development of attenuated vaccine candidates.Here,we review the construction strategies,development,and applications of reverse genetics systems for SARS-CoV-2,which may be applied to other CoVs as well.
基金Project supported by the National Natural Science Foundation ofChina (No. 60374028) and the Scientific Research Foundation forReturned Overseas Chinese Scholars Ministry of Education (No.[2004]176)
文摘This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalized l2 (Gl2) and generalized H2 (GH2) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl2/GH2 control problem can be solved less conservatively using computationally tractable algorithms developed in the paper.
基金supported by the Wuhan Bureau of Science and Technology(No.202002020101010022)China Geological Survey(No.DD20190282)the support team from the National Biosafety Laboratory in Wuhan,China,for the support they extended to us。
文摘Wastewater-based epidemiology(WBE)has emerged as an effective environmental surveillance tool in monitoring fecal-oral pathogen infections within a community.Congruently,SARS-Co V-2,the etiologic agent of COVID-19,has been demonstrated to infect the gastrointestinal tissues,and be shed in feces.In the present study,SARS-Co V-2 RNA was concentrated from wastewater,sludge,surface water,ground water,sediment,and soil samples of municipal and hospital wastewater systems and related environments in Wuhan during the COVID-19 middle and low risk periods,and the viral RNA copies quantified using reverse transcription quantitative polymerase chain reaction(RT-q PCR).From the findings of this study,during the middle risk period,one influent sample and three secondary effluents collected from waste water treatment plant 2,as well as two samples from Jinyintan Hospital wastewater system influent were SARS-Co V-2 RNA positive.One sludge sample collected from Guanggu Branch of Tongji Hospital,which was obtained during the low risk period,was also positive for SARS-Co V-2 RNA.These study findings demonstrate the significance of WBE in continuous surveillance of SARS-Co V-2 at the community level,even when the COVID-19 prevalence is low.Overall,this study can be used as an important reference for contingency management of wastewater treatment plants and COVID-19 prevention and control departments of Wuhan.
基金supported by National Natural Science Foundation of China (Nos.61174073 and 90816028)
文摘This paper investigates L2-gain analysis and anti-windup compensation gains design for a class of discrete-time switched systems with saturating actuators and L2 bounded disturbances by using the switched Lyapunov function approach.For a given set of anti-windup compensation gains,we firstly give a sufficient condition on tolerable disturbances under which the state trajectory starting from the origin will remain inside a bounded set for the corresponding closed-loop switched system subject to L2 bounded disturbances.Then,the upper bound on the restricted L2-gain is obtained over the set of tolerable disturbances.Furthermore,the antiwindup compensation gains aiming to determine the largest disturbance tolerance level and the smallest upper bound of the restricted L2-gain are presented by solving a convex optimization problem with linear matrix inequality(LMI) constraints.A numerical example is given to illustrate the effectiveness of the proposed design method.
基金supported by the Deanship of Scientific Research(DSR)at KFUPM through distinguished professorship project(161065)
文摘This paper addresses an infinite horizon distributed H2/H∞ filtering for discrete-time systems under conditions of bounded power and white stochastic signals. The filter algorithm is designed by computing a pair of gains namely the estimator and the coupling. Herein, we implement a filter to estimate unknown parameters such that the closed-loop multi-sensor accomplishes the desired performances of the proposed H2 and H∞ schemes over a finite horizon. A switched strategy is implemented to switch between the states once the operation conditions have changed due to disturbances. It is shown that the stability of the overall filtering-error system with H2/H∞ performance can be established if a piecewise-quadratic Lyapunov function is properly constructed. A simulation example is given to show the effectiveness of the proposed approach.
文摘The next generation of advanced light sources requires photons with large average flux and high brightness,which needs advanced electron gun matched with excellent photocathode materials. K_(2)CsSb photocathode has the advantages of high quantum efficiency, long lifetime and instantaneous response. This study introduces the design of a set of K_(2)CsSb photocathode preparation systems and detailed preparation process of K_(2)CsSb photocathodes, including sequential deposition process and co-deposition process, and finally develops a K_(2)CsSb photocathode. The influence of laser power on the quantum efficiency is also investigated.
基金supported by Region of Champagne Ardenne and European Regional Development Fund CPER-MOSYP
文摘In this paper, an adaptive type-2 fuzzy sliding mode control to tolerate actuator faults of unknown nonlinear systems with external disturbances is presented. Based on a redundant actuation structure, a novel type-2 adaptive fuzzy fault tolerant control scheme is proposed using sliding mode control. Two adaptive type-2 fuzzy logic systems are used to approximate the unknown functions, whose adaptation laws are deduced from the stability analysis. The proposed approach allows to ensure good tracking performance despite the presence of actuator failures and external disturbances, as illustrated through a simulation example.
基金supported by the National Natural Science Foundation of China(No.60727002,60774003,60921001,90916024)the COSTIND(No.A2120061303)the National 973 Program(No.2005CB321902)
文摘This paper deals with the iterative learning control （ILC） design for multiple-input multiple-output （MIMO）,time-delay systems （TDS）.Two feedback ILC schemes are considered using the so-called two-dimensional （2D） analysis approach.It shows that continuous-discrete 2D Roesser systems can be developed to describe the entire learning dynamics of both ILC schemes,based on which necessary and sufficient conditions for their stability can be provided.A numerical example is included to validate the theoretical analysis.
基金financial support from the National Natural Science Foundation of China (Nos. 11974188,11304159)the China Postdoctoral Science Foundation (Nos. 2021T140339,2018M632345)+2 种基金the Qing Lan Project of Jiangsu Provincethe Natural Science Foundation of Jiangsu Province (Nos. BK20201381,BK20161512)NUPTSF (No. NY218022)。
文摘Molybdenum disulfide (MoS_(2)) with low cost, high activity and high earth abundance has been found to be a promising catalyst for the hydrogen evolution reaction (HER), but its catalytic activity is considerably limited due to its inert basal planes. Here, through the combination of theory and experiment, we propose that doping Ni in MoS_(2) as catalyst can make it have excellent catalytic activity in different reaction systems. In the EY/TEOA system, the maximum hydrogen production rate of EY/Ni-Mo-S is 2.72 times higher than that of pure EY, which confirms the strong hydrogen evolution activity of Ni-Mo-S nanosheets as catalysts. In the lactic acid and Na_(2)S/Na_(2)SO_(3) systems, when Ni-Mo-S is used as co-catalyst to compound with ZnIn_(2)S_(4) (termed as Ni-Mo-S/ZnIn_(2)S_(4)), the maximum hydrogen evolution rates in the two systems are 5.28 and 2.33 times higher than those of pure ZnIn_(2)S_(4), respectively. The difference in HER enhancement is because different systems lead to different sources of protons, thus affecting hydrogen evolution activity. Theoretically, we further demonstrate that the Ni-Mo-S nanosheets have a narrower band gap than MoS_(2), which is conducive to the rapid transfer of charge carriers and thus result in multi-photocatalytic reaction systems with excellent activity. The proposed atomic doping strategy provides a simple and promising approach for the design of photocatalysts with high activity and stability in multi-reaction systems.
基金the National Natural Science Foundation of China(grant no.51474060)the National Key R&D Program of China(grant no.2017 YFC0805100)+1 种基金the National Natural Science Foundation of Liaoning Province(China)(grant no.2019-MS-129)the Fundamental Research Funds for the Central Universities of China(grant no.N162502002).
文摘The molten mixtures of alkali metal fluorides and aluminum fluoride are applied as aluminum electrolytes or brazing fluxes.However,the presence of Al2F-7^-in such molten systems is disputed.In the present study,MF-AlF3(M=K,Cs)systems with molar ratios<1 were studied by in-situ Raman spectroscopy and molecular simulation.The results show that,in addition to AlF6^(3-),AlF5^(2-),and AlF4^-,the systems also contained Al2F-7^-.The characteristic bands in the Raman spectra belonging to Al2F-7^-were located at about 225 cm^-1,315 cm^-1,479 cm^-1,and 720 cm^-1.There are two possible structures of Al2F-7^-,which belong to the D3d and D3hpoint groups.Both of these structures are linear,and their single-point energies were found to differ by only 0.31 kcal/mol.
基金The project supported by National Natural Science Foundation of China under Grant No. 10405019
文摘We study entanglement in dimerized Heisenberg systems. In particular, we give exact results of groundstate pairwise entanglement for the four-qubit model by identifying a Z2 symmetry. Although the entanglements cannot identify the critical point of the system, the mean entanglement of the nearest-neighbor qubits really does, namely, it reaches a maximum at the critical point.
基金Supported by National Natural Science Foundation of China(50977008,60904017,60774048,60728307),the Funds for Creative Research Groups of China(60521003),the Program for Cheung Kong Scholars and Innovative Research Team in University(IRT0421),and the 111 Project(B08015),National High Technology Research and Development Program of China(863 Program)(2006AA04Z183)
文摘This paper is concerned with the problem of stabilization of the Roesser type discrete-time nonlinear 2-D system that plays an important role in many practical applications. First, a discrete-time 2-D T-S fuzzy model is proposed to represent the underlying nonlinear 2-D system. Second, new quadratic stabilization conditions are proposed by applying relaxed quadratic stabilization technique for 2-D case. Third, for sake of further reducing conservatism, new non-quadratic stabilization conditions are also proposed by applying a new parameter-dependent Lyapunov function, matrix transformation technique, and relaxed technique for the underlying discrete-time 2-D T-S fuzzy system. Finally, a numerical example is provided to illustrate the effectiveness of the proposed results.
