To achieve carbon neutrality by 2060,decarbonization in the energy sector is crucial.Hydrogen is expected to be vital for achieving the aim of carbon neutrality for two reasons:use of power-to-hydrogen(P2H)can avoid c...To achieve carbon neutrality by 2060,decarbonization in the energy sector is crucial.Hydrogen is expected to be vital for achieving the aim of carbon neutrality for two reasons:use of power-to-hydrogen(P2H)can avoid carbon emissions from hydrogen production,which is traditionally performed using fossil fuels;Hydrogen from P2H can be stored for long durations in large scales and then delivered as industrial raw material or fed back to the power system depending on the demand.In this study,we focus on the analysis and evaluation of hydrogen value in terms of improvement in the flexibility of the energy system,particularly that derived from hydrogen storage.An electricity-hydrogen coupled energy model is proposed to realize the hourly-level operation simulation and capacity planning optimization aiming at the lowest cost of energy.Based on this model and considering Northwest China as the region of study,the potential of improvement in the flexibility of hydrogen storage is determined through optimization calculations in a series of study cases with various hydrogen demand levels.The results of the quantitative calculations prove that effective hydrogen storage can improve the system flexibility by promoting the energy demand balance over a long term,contributing toward reducing the investment cost of both generators and battery storage and thus the total energy cost.This advantage can be further improved when the hydrogen demand rises.However,a cost reduction by 20%is required for hydrogen-related technologies to initiate hydrogen storage as long-term energy storage for power systems.This study provides a suggestion and reference for the advancement and planning of hydrogen storage development in regions with rich sources of renewable energy.展开更多
This paper analyzes the related concepts of green buildings and hydraulic ecological glass,and explains in detail the market competitiveness of hydraulic ecological glass in green buildings.Finally,it analyzes the con...This paper analyzes the related concepts of green buildings and hydraulic ecological glass,and explains in detail the market competitiveness of hydraulic ecological glass in green buildings.Finally,it analyzes the concept of hydraulic ecological glass design,and summarizes the universality and importance of hydraulic ecological glass in green buildings and modern housing.Through the analysis and application of green building design concept in housing and environment,it is concluded that hydraulic ecological glass has good market competitiveness,and its promotion will have a better impact on the whole green building.展开更多
This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control con...This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.展开更多
Ionizing radiation produces excessive reactive oxygen species (ROS) which impose detrimental effects on biological systems. Thus, it is important to explore clinically safe and efficacious radioprotection agents to ...Ionizing radiation produces excessive reactive oxygen species (ROS) which impose detrimental effects on biological systems. Thus, it is important to explore clinically safe and efficacious radioprotection agents to scavenge ROS and reduce the risks of radiotherapy. Recently, emerging catalytic nanomaterials such as sulfide nanomaterials have shown capability of clearing ROS in vivo by unique electron transfers between atoms, but their catalytic activities are yet suboptimal. As such, there is an unmet need to improve cat- alytic properties for stronger antioxidant activities and radiation protection. Herein, we prepared ultra- small Au-MoS2 clusters (~2.Snm) and they showed enhanced catalytic properties via gold intercalation facilitating increased active sites and synergistic effects. Electrocatalysis results revealed that the catalytic activity of Au-MoS2 towards 1-1202 was superior to ultrasmall MoS2 without Au. As a result, we found that improving the electrocatalytic property of Au-MoS2 can effectively enhance corre- sponding antioxidant activities and radioprotection effects in vivo. In addition, Au-MoS2 also showed sig- nificant radioprotection in vitro and dramatically reduced the excess of radiation-induced adverse ROS. It also rescued radiation-induced DNA damages and protected the bone marrow hematopoietic system from ionizing radiation.展开更多
We study the duality between color and kinematics for the Sudakov form factors of tr(F~2)in non-supersymmetric pure Yang-Mills theory.We construct the integrands that manifest the color-kinematics duality up to two lo...We study the duality between color and kinematics for the Sudakov form factors of tr(F~2)in non-supersymmetric pure Yang-Mills theory.We construct the integrands that manifest the color-kinematics duality up to two loops.The resulting numerators are given in terms of Lorentz products of momenta and polarization vectors,which have the same powers of loop momenta as that from the Feynman rules.The integrands are checked by d-dimensional unitarity cuts and are valid in any dimension.We find that massless-bubble and tadpole topologies are needed at two loops to realize the color-kinematics duality.Interestingly,the two-loop solution contains a large number of free parameters suggesting the duality may hold at higher loop orders.展开更多
基金National Natural Science Foundation of China(program number 51707108)Global Energy Interconnection Group Co.,Ltd.Science and Technology Project(2700/2020-75001B).
文摘To achieve carbon neutrality by 2060,decarbonization in the energy sector is crucial.Hydrogen is expected to be vital for achieving the aim of carbon neutrality for two reasons:use of power-to-hydrogen(P2H)can avoid carbon emissions from hydrogen production,which is traditionally performed using fossil fuels;Hydrogen from P2H can be stored for long durations in large scales and then delivered as industrial raw material or fed back to the power system depending on the demand.In this study,we focus on the analysis and evaluation of hydrogen value in terms of improvement in the flexibility of the energy system,particularly that derived from hydrogen storage.An electricity-hydrogen coupled energy model is proposed to realize the hourly-level operation simulation and capacity planning optimization aiming at the lowest cost of energy.Based on this model and considering Northwest China as the region of study,the potential of improvement in the flexibility of hydrogen storage is determined through optimization calculations in a series of study cases with various hydrogen demand levels.The results of the quantitative calculations prove that effective hydrogen storage can improve the system flexibility by promoting the energy demand balance over a long term,contributing toward reducing the investment cost of both generators and battery storage and thus the total energy cost.This advantage can be further improved when the hydrogen demand rises.However,a cost reduction by 20%is required for hydrogen-related technologies to initiate hydrogen storage as long-term energy storage for power systems.This study provides a suggestion and reference for the advancement and planning of hydrogen storage development in regions with rich sources of renewable energy.
基金Supported by National Innovation and Entrepreneurship Training Program for College Students in 2021(S202110414044)。
文摘This paper analyzes the related concepts of green buildings and hydraulic ecological glass,and explains in detail the market competitiveness of hydraulic ecological glass in green buildings.Finally,it analyzes the concept of hydraulic ecological glass design,and summarizes the universality and importance of hydraulic ecological glass in green buildings and modern housing.Through the analysis and application of green building design concept in housing and environment,it is concluded that hydraulic ecological glass has good market competitiveness,and its promotion will have a better impact on the whole green building.
文摘This article presents an event-triggered H_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. First, considering control constraints, the constrained H_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained Hamilton–Jacobi–Bellman (HJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. Finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.
基金supported by the National Natural Science Foundation of China(81471786)the Independent Innovation Foundation of Tianjin University
文摘Ionizing radiation produces excessive reactive oxygen species (ROS) which impose detrimental effects on biological systems. Thus, it is important to explore clinically safe and efficacious radioprotection agents to scavenge ROS and reduce the risks of radiotherapy. Recently, emerging catalytic nanomaterials such as sulfide nanomaterials have shown capability of clearing ROS in vivo by unique electron transfers between atoms, but their catalytic activities are yet suboptimal. As such, there is an unmet need to improve cat- alytic properties for stronger antioxidant activities and radiation protection. Herein, we prepared ultra- small Au-MoS2 clusters (~2.Snm) and they showed enhanced catalytic properties via gold intercalation facilitating increased active sites and synergistic effects. Electrocatalysis results revealed that the catalytic activity of Au-MoS2 towards 1-1202 was superior to ultrasmall MoS2 without Au. As a result, we found that improving the electrocatalytic property of Au-MoS2 can effectively enhance corre- sponding antioxidant activities and radioprotection effects in vivo. In addition, Au-MoS2 also showed sig- nificant radioprotection in vitro and dramatically reduced the excess of radiation-induced adverse ROS. It also rescued radiation-induced DNA damages and protected the bone marrow hematopoietic system from ionizing radiation.
基金supported in part by the National Natural Science Foundation of China(Grants No.12175291,11935013,11822508,12047503)by the Key Research Program of the Chinese Academy of Sciences,Grant NO.XDPB15。
文摘We study the duality between color and kinematics for the Sudakov form factors of tr(F~2)in non-supersymmetric pure Yang-Mills theory.We construct the integrands that manifest the color-kinematics duality up to two loops.The resulting numerators are given in terms of Lorentz products of momenta and polarization vectors,which have the same powers of loop momenta as that from the Feynman rules.The integrands are checked by d-dimensional unitarity cuts and are valid in any dimension.We find that massless-bubble and tadpole topologies are needed at two loops to realize the color-kinematics duality.Interestingly,the two-loop solution contains a large number of free parameters suggesting the duality may hold at higher loop orders.