Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage devices.However,the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered ...Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage devices.However,the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide (CoNi-LDH) as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline electrolytes.Herein,CoNi-LDH nanosheets enriched with H vacancies (CoNi-LDH(v)) were constructed on a flexible carbon cloth (CC) substrate via electrochemical deposition and activation.The Zn-based battery comprising CoNi-LDH(v)@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnSO4electrolyte (pH=4).The battery delivered an excellent specific capacity (225 mA h g^(-1),0.26 mA h cm^(-2)),acceptable cycling stability(53.9%,900 cycles),and high discharging voltage.The abundant H vacancies served as active sites for the reversible intercalation of Zn^(2+)and the extravasation of NO_(3)-generated channels and space for Zn^(2+)transport and storage,together enabling an excellent Zn^(2+)storage capacity.Furthermore,a sandwich-structured solid-state CoNi-LDH(v)@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical durability.As a proof of concept,the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 h.Additionally,the flexible battery displayed outstanding customizability,maintaining an open-circuit voltage of 1.42 V even after being cut twice.The proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.展开更多
In this paper,we study the(α,β)-metrics of constant flag curvature.We characterize almost regular(α,β)-metrics of constant flag curvature under the condition that β is a homothetic 1-form with respect to a.Furthe...In this paper,we study the(α,β)-metrics of constant flag curvature.We characterize almost regular(α,β)-metrics of constant flag curvature under the condition that β is a homothetic 1-form with respect to a.Furthermore,we prove that if a regular(α,β)-metric is of constant flag curvature and β is a Killing 1-form with constant length,then it must be a Riemannian metric or locally Minkowskian.展开更多
Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible e...Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical deformations.Herein,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal strategy.The aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage kinetics.The high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and CoO.Furthermore,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical deformations.As a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical deformations.The proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.展开更多
For an(α, β)-metric(non-Randers type) of isotropic S-curvature on an n-dimensional manifold with non-constant norm ‖β‖α, we first show that n = 2, and then we characterize such a class of two-dimensional(α, β)...For an(α, β)-metric(non-Randers type) of isotropic S-curvature on an n-dimensional manifold with non-constant norm ‖β‖α, we first show that n = 2, and then we characterize such a class of two-dimensional(α, β)-manifolds with some PDEs, and also construct some examples for such a class.展开更多
This study assesses the seasonal regulation of river discharge by hydropower dam-induced cascade reservoirs in the Lancang River and its effect on downstream freshwater and estuarine saltwater intrusion.There are eigh...This study assesses the seasonal regulation of river discharge by hydropower dam-induced cascade reservoirs in the Lancang River and its effect on downstream freshwater and estuarine saltwater intrusion.There are eight main reservoirs in the Lancang River,with a total regulation capacity of 25.67 billion m3,which regulates river discharge by conserving water in the flood season and releasing water in the dry season.River discharge during the dry season from 1960 to 2009 accounted for 21%of the annual discharge before the cascade reservoirs were constructed and increased to 33%from 2010 to 2015 after the cascade reservoirs were constructed at the Jinghong hydrological station,which is the lowermost station in the Lancang River.During the 2016 extreme drought in the lower Mekong River basin,the river discharge increased by 550,367,1283,969,and 524 m3/s in January,February,March,April,and May,respectively,regulated by the cascade reservoirs at the Jinghong hydrological station.Considering runoff,tides,wind,and continental shelf currents,a high-resolution three-dimensional numerical model was used to simulate the effect of regulation of river discharge by the cascade reservoirs in the Lancang River on the saltwater intrusion in the Mekong River Delta(MRD).The simulation results show that the seasonal regulation of river discharge by the cascade reservoirs in the Lancang River weakens estuarine saltwater intrusion during the dry season,especially in the sand bar areas,which is much more significant in the extreme dry season of 2016.The seasonal regulation of river discharge by the reservoirs in the Lancang River makes the seasonal distribution of downstream river discharge more uniform,favoring down-stream freshwater utilization and alleviating flood disasters and saltwater intrusion in the MRD.展开更多
基金National Natural Science Foundation of China (52003191,5247317, 52473275)Young Elite Scientists Sponsorship Program by CAST (2022QNRC001)+3 种基金Natural Science Foundation of Jiangsu Province (BK20221539)Postgraduate Research&Practice Innovation Program of Jiangsu Province (KYCX22_2341)Program of Introducing Talents of Jiangnan University (1065219032210150)Program of China Scholarship Council (202306790065)。
文摘Flexible Zn-based batteries have attracted increasing research interest as essential components of wearable energy storage devices.However,the advancement of flexible aqueous Zn-based batteries based on Co-Ni layered double hydroxide (CoNi-LDH) as the cathode material is hampered by their poor cycling stability and the corrosiveness of alkaline electrolytes.Herein,CoNi-LDH nanosheets enriched with H vacancies (CoNi-LDH(v)) were constructed on a flexible carbon cloth (CC) substrate via electrochemical deposition and activation.The Zn-based battery comprising CoNi-LDH(v)@CC as the cathode exhibited highly reversible conversion reactions and stable operation in 3 M ZnSO4electrolyte (pH=4).The battery delivered an excellent specific capacity (225 mA h g^(-1),0.26 mA h cm^(-2)),acceptable cycling stability(53.9%,900 cycles),and high discharging voltage.The abundant H vacancies served as active sites for the reversible intercalation of Zn^(2+)and the extravasation of NO_(3)-generated channels and space for Zn^(2+)transport and storage,together enabling an excellent Zn^(2+)storage capacity.Furthermore,a sandwich-structured solid-state CoNi-LDH(v)@CC//Zn@CC battery was fabricated and was found to exhibit a noteworthy electrochemical performance and mechanical durability.As a proof of concept,the unencapsulated battery powered a digital watch under various deformation conditions and operated stably for 80 h.Additionally,the flexible battery displayed outstanding customizability,maintaining an open-circuit voltage of 1.42 V even after being cut twice.The proposed engineering strategy contributes to the realization of textiles with truly wearable energy-storage devices.
基金supported by the NationalNatural Science Foundation of China(11871126)the Science Foundation of Chongqing Normal University(17XLB022)。
文摘In this paper,we study the(α,β)-metrics of constant flag curvature.We characterize almost regular(α,β)-metrics of constant flag curvature under the condition that β is a homothetic 1-form with respect to a.Furthermore,we prove that if a regular(α,β)-metric is of constant flag curvature and β is a Killing 1-form with constant length,then it must be a Riemannian metric or locally Minkowskian.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20201343 and BK20221539)China Postdoctoral Science Foundation(No.2018T110442 and 2017M610296)+3 种基金Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_2341)National Natural Science Foundation of China(No.52003191 and 21201083)the Open Project Program of Fujian Key Laboratory of Novel Functional Textile Fibres and Materials,Minjiang University,China(No.FKLTFM1902 and FKLTFM2005)the Open Project Program of State Key Laboratory of Molecular Engineering of Polymers,Fudan University,China(No.K2022-31).
文摘Yarn-based batteries with the dual functions of wearable and energy storage have demonstrated promising potential in wearable energy textiles.However,it is still an urgent problem to construct efficient and flexible electrodes while optimize the configuration of yarn-based batteries to maintain excellent electrochemical performance under different mechanical deformations.Herein,NiCo_(2)S_(4-x) nanotube arrays with tunable S-vacancies are constructed on carbon yarn(CY)(NiCo_(2)S_(4-x)@CY)by a facile hydrothermal strategy.The aqueous zinc-ion batteries(ZIBs)with NiCo_(2)S_(4-x)@CY as cathodes exhibit exceptional discharge capacity(271.7 mAh g^(-1))and outstanding rate performance(70.9%capacity retention at 5 A g^(-1)),and reveal a maximum power density of 6,059.5 W kg^(-1) and a maximum energy density of 432.2 Wh kg^(-1).It is worth noting that the tunable S-vacancies promote the surface reconfiguration and phase transitions of NiCo_(2)S_(4-x),thereby enhancing the conductivity and charge storage kinetics.The high reactivity and cycling stability of NiCo_(2)S_(4-x)@CY can be related to the discharge products of S-doped NiO and CoO.Furthermore,flexible stretchable yarn-based ZIBs with wrapped yarn structures are constructed and exhibit excellent tensile stability and durability under a variety of mechanical deformations.As a proof of concept,the ZIBs integrated into the fabric show excellent electrochemical performance even in response to simultaneous stretching and bending mechanical deformations.The proposed strategy provides novel inspiration for the development of highly efficient and economical yarn-based ZIBs and wearable energy textiles.
基金supported by National Natural Science Foundation of China(Grant Nos.11371386 and 11471226)the European Union’s Seventh Framework Programme(FP7/2007-2013)(Grant No.317721)
文摘For an(α, β)-metric(non-Randers type) of isotropic S-curvature on an n-dimensional manifold with non-constant norm ‖β‖α, we first show that n = 2, and then we characterize such a class of two-dimensional(α, β)-manifolds with some PDEs, and also construct some examples for such a class.
基金supported by the International Joint Laboratory of Estuarine and Coastal Research,Shanghai(21230750600).
文摘This study assesses the seasonal regulation of river discharge by hydropower dam-induced cascade reservoirs in the Lancang River and its effect on downstream freshwater and estuarine saltwater intrusion.There are eight main reservoirs in the Lancang River,with a total regulation capacity of 25.67 billion m3,which regulates river discharge by conserving water in the flood season and releasing water in the dry season.River discharge during the dry season from 1960 to 2009 accounted for 21%of the annual discharge before the cascade reservoirs were constructed and increased to 33%from 2010 to 2015 after the cascade reservoirs were constructed at the Jinghong hydrological station,which is the lowermost station in the Lancang River.During the 2016 extreme drought in the lower Mekong River basin,the river discharge increased by 550,367,1283,969,and 524 m3/s in January,February,March,April,and May,respectively,regulated by the cascade reservoirs at the Jinghong hydrological station.Considering runoff,tides,wind,and continental shelf currents,a high-resolution three-dimensional numerical model was used to simulate the effect of regulation of river discharge by the cascade reservoirs in the Lancang River on the saltwater intrusion in the Mekong River Delta(MRD).The simulation results show that the seasonal regulation of river discharge by the cascade reservoirs in the Lancang River weakens estuarine saltwater intrusion during the dry season,especially in the sand bar areas,which is much more significant in the extreme dry season of 2016.The seasonal regulation of river discharge by the reservoirs in the Lancang River makes the seasonal distribution of downstream river discharge more uniform,favoring down-stream freshwater utilization and alleviating flood disasters and saltwater intrusion in the MRD.
