The Yangtze River,with a length of approximately 6300 km,holds the distinction of being the largest river in East Asia that empties into the Pacific Ocean.Its formation is intricately linked to regional tectonic activ...The Yangtze River,with a length of approximately 6300 km,holds the distinction of being the largest river in East Asia that empties into the Pacific Ocean.Its formation is intricately linked to regional tectonic activity and climate fluctuations.However,the exact timeline for the formation of the Yangtze River remains elusive.This study investigates the provenance of the Late Cenozoic strata in the Wangjiang Basin,situated in the Lower Yangtze River,through the application of detrital zircon U-Pb dating.Seven sand samples were analyzed,leading to the identification of new U-Pb detrital zircon ages(n=577).Our study reveals that the sand materials found in the Pliocene gravel beds of the Anqing Formation originate predominantly from the Yangtze River.The findings of our study,along with the provenance tracing of boreholes in the Yangtze River Basin and the shelf sea in East China,provide compelling evidence for the continuous presence of the Yangtze River throughout the Pliocene period.The development of the Yangtze River during the Pliocene is intricately connected to both the tectonic adjustments occurring at the southeastern margin of the Tibetan Plateau and the intensification of the Asian Monsoon.展开更多
The construction and operation of the Three Gorges Reservoir and the cascade reservoirs upstream have significantly altered the processes offlow and sediment in the main and tributary channels of the Yangtze River.Thi...The construction and operation of the Three Gorges Reservoir and the cascade reservoirs upstream have significantly altered the processes offlow and sediment in the main and tributary channels of the Yangtze River.This has led to substantial adjustments in the riverbed through erosion and deposition,thereby impactingflood protection,water resource utilization,navigation,and the aquatic environ-ment in the Yangtze River basin.In this study,prototype measurements were used to analyze the variations in runoff and sediment load in the main channel of the Yangtze River,as well as the changes and evolution of the riverbed.Mathematical modeling was done to predict the trends in reservoir sedimentation and riverbed adjustments.The results indicate that,apart from the significantly increased runoff and sediment load in the river source region(Zhimenda station)over the past two decades,there is no clear unidirectional trend of increasing or decreasing in the main and tributary annual runoff of the Yangtze River.However,the release of reservoir outflows undergoes significant changes throughout the year due to reservoir regulation.Suspended sediment load in the upper Yangtze River has been decreasing since the 1990s,especially after the operation of the Three Gorges Reservoir and the four cascade reservoirs in the lower reach of the Jinsha River.The factors influencingflow and sediment variations include mainly climate change and human activities such as reservoir operation and soil and water conservation.The significant changes inflow and sediment conditions have disrupted the original relative equilibrium state of the main channel of the Yangtze River,leading to riverbed adjustments.The river sections in the upper reach,located within reservoir areas,have shifted from erosional state under natural conditions to accumulative state,while the middle and lower reaches have transitioned from a relatively equilibrium state to a process dominated by erosion and reconstruction.Overall,the river regime in the reservoir area and downstream of the Three Gorges Dam remains relatively stable,but there have been adjustments in some local river sections,for example,in the curved sections,particularly in the sharply curved sections downstream of the Three Gorges Dam,where gradual or abrupt chute cutoff has occurred.In the foreseeable future,the river channel downstream of the Three Gorges Dam will remain in an unsaturated state regarding sediment transport.The process of river channel erosion will persist for a long time and have far-reaching consequences.Some long straight sections,multiple bifurcation sections,and sections with large curvature are expected to undergo certain adjustments in the river regime,necessitating continuous observation,long-term monitoring,and timely river management and channel governance.展开更多
The electrochemical CO_(2)reduction reaction(CO_(2)RR)provides a promising approach to mitigate the global greenhouse effect by converting CO_(2)into high-value chemicals or fuels.Noble metal-based nanomaterials are w...The electrochemical CO_(2)reduction reaction(CO_(2)RR)provides a promising approach to mitigate the global greenhouse effect by converting CO_(2)into high-value chemicals or fuels.Noble metal-based nanomaterials are widely regarded as efficient catalysts for CO_(2)RR due to their high catalytic activity and excellent stability.However,these catalysts typically favor the formation of C1 products,which have relatively low economic value.Moreover,the high cost and limited availability of noble materials necessitate strategies to reduce their usage,often by dispersing them on suitable support materials to enhance catalytic performance.In this study,a novel metal-based support,zirconium phosphate Zr_(3)(PO_(4))_(4),was used to anchor ultrasmall palladium nanoparticles(pre-ZrP-Pd).Compared to the reversible hydrogen electrode,the pre-ZrP-Pd achieved a maximum Faradaic efficiency(FE)of 92.1%for ethanol at−0.8 V versus RHE,along with a peak ethanol current density of 0.82 mA/cm^(2).Density functional theory(DFT)calculations revealed that the strong metal-support interactions between the ZrP support and Pd nanoparticles lead to an upward shift of the Pd d-band center,enhancing the adsorption of CO^(*) and promoting the coupling of CO and CO to produce ethanol.展开更多
The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an...The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an a-phase indium selenide(a-In_(2)Se_(3))transistor,which is a two-dimensional ferroelectric semiconductor as the channel material,to create artificial optic-neural and electro-neural synapses,enabling cutting-edge processing-in-sensor(PIS)and computing-in-memory(CIM)functionalities.As an optic-neural synapse for low-level sensory processing,the a-In_(2)Se_(3)transistor exhibits a high photoresponsivity(2855 A/W)and detectivity(2.91×10^(14)Jones),facilitating efficient feature extraction.For high-level processing tasks as an electro-neural synapse,it offers a fast program/erase speed of 40 ns/50μs and ultralow energy consumption of 0.37 aJ/spike.An AI vision system using a-In_(2)Se_(3)transistors has been demonstrated.It achieved an impressive recognition accuracy of 92.63%within 12 epochs owing to the synergistic combination of the PIS and CIM functionalities.This study demonstrates the potential of the a-In_(2)Se_(3)transistor in future vision hardware,enhancing processing,power efficiency,and AI applications.展开更多
In this paper,a new recursive implementation of composite adaptive control for robot manipulators is proposed.We investigate the recursive composite adaptive algorithm and prove the stability directly based on the New...In this paper,a new recursive implementation of composite adaptive control for robot manipulators is proposed.We investigate the recursive composite adaptive algorithm and prove the stability directly based on the Newton-Euler equations in matrix form,which,to our knowledge,is the first result on this point in the literature.The proposed algorithm has an amount of computation O(n),which is less than any existing similar algorithms and can satisfy the computation need of the complicated multidegree manipulators.The manipulator of the Chinese Space Station is employed as a simulation example,and the results verify the effectiveness of this proposed recursive algorithm.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42030305W2411033)Research Foundation of Chutian Scholars Program of Hubei Province(No.8210403)。
文摘The Yangtze River,with a length of approximately 6300 km,holds the distinction of being the largest river in East Asia that empties into the Pacific Ocean.Its formation is intricately linked to regional tectonic activity and climate fluctuations.However,the exact timeline for the formation of the Yangtze River remains elusive.This study investigates the provenance of the Late Cenozoic strata in the Wangjiang Basin,situated in the Lower Yangtze River,through the application of detrital zircon U-Pb dating.Seven sand samples were analyzed,leading to the identification of new U-Pb detrital zircon ages(n=577).Our study reveals that the sand materials found in the Pliocene gravel beds of the Anqing Formation originate predominantly from the Yangtze River.The findings of our study,along with the provenance tracing of boreholes in the Yangtze River Basin and the shelf sea in East China,provide compelling evidence for the continuous presence of the Yangtze River throughout the Pliocene period.The development of the Yangtze River during the Pliocene is intricately connected to both the tectonic adjustments occurring at the southeastern margin of the Tibetan Plateau and the intensification of the Asian Monsoon.
基金Changjiang Water Science Research Joint Fund of the National Natural Science Foundation of China,Grant/Award Numbers:U2240206,U2240224Research Project on Major Scientific and Technological Issues in Watershed Water Management of MWR of China,Grant/Award Number:CKSC2020791/HL+2 种基金Fundamental Research Funds for Central Public Welfare Research Institutes of China,Grant/Award Number:CKSF2023328/HLKey Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province of China,Grant/Award Number:2021SS01Natural Science Foundation of Hubei Province,Grant/Award Number:2021CFB146。
文摘The construction and operation of the Three Gorges Reservoir and the cascade reservoirs upstream have significantly altered the processes offlow and sediment in the main and tributary channels of the Yangtze River.This has led to substantial adjustments in the riverbed through erosion and deposition,thereby impactingflood protection,water resource utilization,navigation,and the aquatic environ-ment in the Yangtze River basin.In this study,prototype measurements were used to analyze the variations in runoff and sediment load in the main channel of the Yangtze River,as well as the changes and evolution of the riverbed.Mathematical modeling was done to predict the trends in reservoir sedimentation and riverbed adjustments.The results indicate that,apart from the significantly increased runoff and sediment load in the river source region(Zhimenda station)over the past two decades,there is no clear unidirectional trend of increasing or decreasing in the main and tributary annual runoff of the Yangtze River.However,the release of reservoir outflows undergoes significant changes throughout the year due to reservoir regulation.Suspended sediment load in the upper Yangtze River has been decreasing since the 1990s,especially after the operation of the Three Gorges Reservoir and the four cascade reservoirs in the lower reach of the Jinsha River.The factors influencingflow and sediment variations include mainly climate change and human activities such as reservoir operation and soil and water conservation.The significant changes inflow and sediment conditions have disrupted the original relative equilibrium state of the main channel of the Yangtze River,leading to riverbed adjustments.The river sections in the upper reach,located within reservoir areas,have shifted from erosional state under natural conditions to accumulative state,while the middle and lower reaches have transitioned from a relatively equilibrium state to a process dominated by erosion and reconstruction.Overall,the river regime in the reservoir area and downstream of the Three Gorges Dam remains relatively stable,but there have been adjustments in some local river sections,for example,in the curved sections,particularly in the sharply curved sections downstream of the Three Gorges Dam,where gradual or abrupt chute cutoff has occurred.In the foreseeable future,the river channel downstream of the Three Gorges Dam will remain in an unsaturated state regarding sediment transport.The process of river channel erosion will persist for a long time and have far-reaching consequences.Some long straight sections,multiple bifurcation sections,and sections with large curvature are expected to undergo certain adjustments in the river regime,necessitating continuous observation,long-term monitoring,and timely river management and channel governance.
文摘The electrochemical CO_(2)reduction reaction(CO_(2)RR)provides a promising approach to mitigate the global greenhouse effect by converting CO_(2)into high-value chemicals or fuels.Noble metal-based nanomaterials are widely regarded as efficient catalysts for CO_(2)RR due to their high catalytic activity and excellent stability.However,these catalysts typically favor the formation of C1 products,which have relatively low economic value.Moreover,the high cost and limited availability of noble materials necessitate strategies to reduce their usage,often by dispersing them on suitable support materials to enhance catalytic performance.In this study,a novel metal-based support,zirconium phosphate Zr_(3)(PO_(4))_(4),was used to anchor ultrasmall palladium nanoparticles(pre-ZrP-Pd).Compared to the reversible hydrogen electrode,the pre-ZrP-Pd achieved a maximum Faradaic efficiency(FE)of 92.1%for ethanol at−0.8 V versus RHE,along with a peak ethanol current density of 0.82 mA/cm^(2).Density functional theory(DFT)calculations revealed that the strong metal-support interactions between the ZrP support and Pd nanoparticles lead to an upward shift of the Pd d-band center,enhancing the adsorption of CO^(*) and promoting the coupling of CO and CO to produce ethanol.
基金supported by the National Natural Science Foundation of China(62104066,52221001,62090035,U19A2090,U22A20138,52372146,and 62101181)the National Key R&D Program of China(2022YFA1402501,2022YFA1204300)+6 种基金the Natural Science Foundation of Hunan Province(2021JJ20016)the Science and Technology Innovation Program of Hunan Province(2021RC3061)the Key Program of Science and Technology Department of Hunan Province(2019XK2001,2020XK2001)the Open Project Program of Wuhan National Laboratory for Optoelectronics(2020WNLOKF016)the Open Project Program of Key Laboratory of Nanodevices and Applications,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(22ZS01)the Project funded by China Postdoctoral Science Foundation(2023TQ0110)the Innovation Project of Optics Valley Laboratory(OVL2023ZD002).
文摘The growth of data and Internet of Things challenges traditional hardware,which encounters efficiency and power issues owing to separate functional units for sensors,memory,and computation.In this study,we designed an a-phase indium selenide(a-In_(2)Se_(3))transistor,which is a two-dimensional ferroelectric semiconductor as the channel material,to create artificial optic-neural and electro-neural synapses,enabling cutting-edge processing-in-sensor(PIS)and computing-in-memory(CIM)functionalities.As an optic-neural synapse for low-level sensory processing,the a-In_(2)Se_(3)transistor exhibits a high photoresponsivity(2855 A/W)and detectivity(2.91×10^(14)Jones),facilitating efficient feature extraction.For high-level processing tasks as an electro-neural synapse,it offers a fast program/erase speed of 40 ns/50μs and ultralow energy consumption of 0.37 aJ/spike.An AI vision system using a-In_(2)Se_(3)transistors has been demonstrated.It achieved an impressive recognition accuracy of 92.63%within 12 epochs owing to the synergistic combination of the PIS and CIM functionalities.This study demonstrates the potential of the a-In_(2)Se_(3)transistor in future vision hardware,enhancing processing,power efficiency,and AI applications.
基金This work was supported by the Major Project of the New Generation of Artificial Intelligence(No.2018AAA0102900).
文摘In this paper,a new recursive implementation of composite adaptive control for robot manipulators is proposed.We investigate the recursive composite adaptive algorithm and prove the stability directly based on the Newton-Euler equations in matrix form,which,to our knowledge,is the first result on this point in the literature.The proposed algorithm has an amount of computation O(n),which is less than any existing similar algorithms and can satisfy the computation need of the complicated multidegree manipulators.The manipulator of the Chinese Space Station is employed as a simulation example,and the results verify the effectiveness of this proposed recursive algorithm.
