Spatial heterogeneity or“patchiness”of plankton distributions in the ocean has always been an attractive and challenging scientific issue to oceanographers.We focused on the accumulation and dynamic mechanism of the...Spatial heterogeneity or“patchiness”of plankton distributions in the ocean has always been an attractive and challenging scientific issue to oceanographers.We focused on the accumulation and dynamic mechanism of the Acetes chinensis in the Lianyungang nearshore licensed fishing area.The Lagrangian frame approaches including the Lagrangian coherent structures theory,Lagrangian residual current,and Lagrangian particle-tracking model were applied to find the transport pathways and aggregation characteristics of Acetes chinensis.There exist some material transport pathways for Acetes chinensis passing through the licensed fishing area,and Acetes chinensis is easy to accumulate in the licensed fishing area.The main mechanism forming this distribution pattern is the local circulation induced by the nonlinear interaction of topography and tidal flow.Both the Lagrangian coherent structure analysis and the particle trajectory tracking indicate that Acetes chinensis in the licensed fishing area come from the nearshore estuary.This work contributed to the adjustment of licensed fishing area and the efficient utilization of fishery resources.展开更多
For decades,the rapid development of wireless communication has provided people a smarter way of living.However,a significant increase in electromagnetic pollution is an unavoidable consequence.Evading radar detection...For decades,the rapid development of wireless communication has provided people a smarter way of living.However,a significant increase in electromagnetic pollution is an unavoidable consequence.Evading radar detection in modern warfare has also become an important prerequisite for survival on the battlefield.This review provides a comprehensive overview of the current status and types of electromagnetic absorption metamaterials,especially their design and preparation methods.Moreover,this review focuses on the strategies used to optimize the absorber absorption performance.Finally,this review presents a viewpoint on future research on electromagnetic absorption metamaterials,the main challenges that need to be addressed and the possible solutions.展开更多
Thermal cloaks offer the potential to conceal internal objects from detection or to prevent thermal shock by controlling external heat flow. However, most conventional natural materials lack the desired flexibility an...Thermal cloaks offer the potential to conceal internal objects from detection or to prevent thermal shock by controlling external heat flow. However, most conventional natural materials lack the desired flexibility and versatility required for on-demand thermal manipulation. We propose a solution in the form of homogeneous multilayer thermodynamic cloaks. Through an ingenious design, these cloaks achieve exceptional and extreme parameters, enabling the distribution of multiple materials in space. We first investigate the effects of important design parameters on the thermal shielding effectiveness of conventional thermal cloaks. Subsequently, we introduce an autonomous tuning function for the thermodynamic cloak, accomplished by leveraging two phase transition materials as thermal conductive layers. Remarkably, this tuning function does not require any energy input. Finite element analysis results demonstrate a significant reduction in the temperature gradient inside the thermal cloak compared to the surrounding background. This reduction indicates the cloak’s remarkable ability to manipulate the spatial thermal field. Furthermore, the utilization of materials undergoing phase transition leads to an increase in thermal conductivity, enabling the cloak to achieve the opposite variation of the temperature field between the object region and the background. This means that, while the temperature gradient within the cloak decreases, the temperature gradient in the background increases. This work addresses a compelling and crucial challenge in the realm of thermal metamaterials, i.e., autonomous tuning of the thermal field without energy input. Such an achievement is currently unattainable with existing natural materials. This study establishes the groundwork for the application of thermal metamaterials in thermodynamic cloaks, with potential extensions into thermal energy harvesting, thermal camouflage, and thermoelectric conversion devices.By harnessing phonons, our findings provide an unprecedented and practical approach to flexibly implementing thermal cloaks and manipulating heat flow.展开更多
Typhoon has an impact on an estuary and coastal environment.However,the present research lacks the detailed description of material transport processes during typhoon passage,such as the transport channels and barrier...Typhoon has an impact on an estuary and coastal environment.However,the present research lacks the detailed description of material transport processes during typhoon passage,such as the transport channels and barriers in the course of material transport and material accumulation area,etc.Therefore,Lagrangian coherent structures(a method developed for describing the transport structure of fluids in recent years)was introduced to investigate and predict the floating material and debris transport process in the Laizhou Bay,Bohai Sea,during typhoon Lekima in 2019.Results show that the Lagrangian coherent structure could well explain the complex flow phenomena in the bay.During the typhoon,the general direction of floating material transport in the Laizhou Bay was anticlockwise.There was a channel for material transport in the northwest and south of the bay,and there are transportation obstacles in the northeast-southwest direction in the middle of the bay.Therefore,the typhoon might worsen the water quality.These results provide references for precise countermeasures to control the formulation of pollution in the Laizhou Bay.展开更多
Erratum to:https://doi.org/10.1007/s00343-021-0384-7 The authors’affiliations of this article contain a few mistakes.The correct ones are given below:1 College of Environmental Science and Engineering,Ocean Universit...Erratum to:https://doi.org/10.1007/s00343-021-0384-7 The authors’affiliations of this article contain a few mistakes.The correct ones are given below:1 College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China 2 Key Laboratory of Marine Environment and Ecology,Ministry of Education of China,Ocean University of China,Qingdao 266100,China The online version of the original articles can be found at:https://doi.org/10.1007/s00343-021-0384-7.展开更多
The Hopf dual H~? of any Poisson Hopf algebra H is proved to be a co-Poisson Hopf algebra provided H is noetherian. Without noetherian assumption, unlike it is claimed in literature, the statement does not hold. It is...The Hopf dual H~? of any Poisson Hopf algebra H is proved to be a co-Poisson Hopf algebra provided H is noetherian. Without noetherian assumption, unlike it is claimed in literature, the statement does not hold. It is proved that there is no nontrivial Poisson Hopf structure on the universal enveloping algebra of a non-abelian Lie algebra. So the polynomial Hopf algebra, viewed as the universal enveloping algebra of a finite-dimensional abelian Lie algebra, is considered. The Poisson Hopf structures on polynomial Hopf algebras are exactly linear Poisson structures. The co-Poisson structures on polynomial Hopf algebras are characterized.Some correspondences between co-Poisson and Poisson structures are also established.展开更多
A double Ore extension was introduced by Zhang and Zhang(2008)to study a class of ArtinShelter regular algebras.Here we give a definition of Poisson double extension which may be considered as an analogue of the doubl...A double Ore extension was introduced by Zhang and Zhang(2008)to study a class of ArtinShelter regular algebras.Here we give a definition of Poisson double extension which may be considered as an analogue of the double Ore extension,and show that algebras in a class of double Ore extensions are deformation quantizations of Poisson double extensions.We also investigate the modular derivations of Poisson double extensions and the relationship between Poisson double extensions and iterated Poisson polynomial extensions.Results are illustrated by examples.展开更多
基金the National Natural Science Foundation of China(No.31802297)。
文摘Spatial heterogeneity or“patchiness”of plankton distributions in the ocean has always been an attractive and challenging scientific issue to oceanographers.We focused on the accumulation and dynamic mechanism of the Acetes chinensis in the Lianyungang nearshore licensed fishing area.The Lagrangian frame approaches including the Lagrangian coherent structures theory,Lagrangian residual current,and Lagrangian particle-tracking model were applied to find the transport pathways and aggregation characteristics of Acetes chinensis.There exist some material transport pathways for Acetes chinensis passing through the licensed fishing area,and Acetes chinensis is easy to accumulate in the licensed fishing area.The main mechanism forming this distribution pattern is the local circulation induced by the nonlinear interaction of topography and tidal flow.Both the Lagrangian coherent structure analysis and the particle trajectory tracking indicate that Acetes chinensis in the licensed fishing area come from the nearshore estuary.This work contributed to the adjustment of licensed fishing area and the efficient utilization of fishery resources.
基金the National Natural Science Foundation of China(Grant No.11774278)the Fundamental Research Funds for Central Universities(No.2012jdgz04)。
文摘For decades,the rapid development of wireless communication has provided people a smarter way of living.However,a significant increase in electromagnetic pollution is an unavoidable consequence.Evading radar detection in modern warfare has also become an important prerequisite for survival on the battlefield.This review provides a comprehensive overview of the current status and types of electromagnetic absorption metamaterials,especially their design and preparation methods.Moreover,this review focuses on the strategies used to optimize the absorber absorption performance.Finally,this review presents a viewpoint on future research on electromagnetic absorption metamaterials,the main challenges that need to be addressed and the possible solutions.
基金supported by the National Natural Science Foundation of China (Grant No. 11774278)the Fundamental Research Funds for Central Universities (Grant No. 2012jdgz04)。
文摘Thermal cloaks offer the potential to conceal internal objects from detection or to prevent thermal shock by controlling external heat flow. However, most conventional natural materials lack the desired flexibility and versatility required for on-demand thermal manipulation. We propose a solution in the form of homogeneous multilayer thermodynamic cloaks. Through an ingenious design, these cloaks achieve exceptional and extreme parameters, enabling the distribution of multiple materials in space. We first investigate the effects of important design parameters on the thermal shielding effectiveness of conventional thermal cloaks. Subsequently, we introduce an autonomous tuning function for the thermodynamic cloak, accomplished by leveraging two phase transition materials as thermal conductive layers. Remarkably, this tuning function does not require any energy input. Finite element analysis results demonstrate a significant reduction in the temperature gradient inside the thermal cloak compared to the surrounding background. This reduction indicates the cloak’s remarkable ability to manipulate the spatial thermal field. Furthermore, the utilization of materials undergoing phase transition leads to an increase in thermal conductivity, enabling the cloak to achieve the opposite variation of the temperature field between the object region and the background. This means that, while the temperature gradient within the cloak decreases, the temperature gradient in the background increases. This work addresses a compelling and crucial challenge in the realm of thermal metamaterials, i.e., autonomous tuning of the thermal field without energy input. Such an achievement is currently unattainable with existing natural materials. This study establishes the groundwork for the application of thermal metamaterials in thermodynamic cloaks, with potential extensions into thermal energy harvesting, thermal camouflage, and thermoelectric conversion devices.By harnessing phonons, our findings provide an unprecedented and practical approach to flexibly implementing thermal cloaks and manipulating heat flow.
基金Supported by the National Natural Science Foundation of China(No.41974085)the National Key R&D Program of China(No.2019YFC1408100)。
文摘Typhoon has an impact on an estuary and coastal environment.However,the present research lacks the detailed description of material transport processes during typhoon passage,such as the transport channels and barriers in the course of material transport and material accumulation area,etc.Therefore,Lagrangian coherent structures(a method developed for describing the transport structure of fluids in recent years)was introduced to investigate and predict the floating material and debris transport process in the Laizhou Bay,Bohai Sea,during typhoon Lekima in 2019.Results show that the Lagrangian coherent structure could well explain the complex flow phenomena in the bay.During the typhoon,the general direction of floating material transport in the Laizhou Bay was anticlockwise.There was a channel for material transport in the northwest and south of the bay,and there are transportation obstacles in the northeast-southwest direction in the middle of the bay.Therefore,the typhoon might worsen the water quality.These results provide references for precise countermeasures to control the formulation of pollution in the Laizhou Bay.
基金Supported by the National Natural Science Foundation of China(No.41974085)the National Key R&D Program of China(No.2019YFC1408100)。
文摘Erratum to:https://doi.org/10.1007/s00343-021-0384-7 The authors’affiliations of this article contain a few mistakes.The correct ones are given below:1 College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China 2 Key Laboratory of Marine Environment and Ecology,Ministry of Education of China,Ocean University of China,Qingdao 266100,China The online version of the original articles can be found at:https://doi.org/10.1007/s00343-021-0384-7.
基金supported by National Natural Science Foundation of China (Grant Nos. 11331006 and 11171067)
文摘The Hopf dual H~? of any Poisson Hopf algebra H is proved to be a co-Poisson Hopf algebra provided H is noetherian. Without noetherian assumption, unlike it is claimed in literature, the statement does not hold. It is proved that there is no nontrivial Poisson Hopf structure on the universal enveloping algebra of a non-abelian Lie algebra. So the polynomial Hopf algebra, viewed as the universal enveloping algebra of a finite-dimensional abelian Lie algebra, is considered. The Poisson Hopf structures on polynomial Hopf algebras are exactly linear Poisson structures. The co-Poisson structures on polynomial Hopf algebras are characterized.Some correspondences between co-Poisson and Poisson structures are also established.
基金supported by National Natural Science Foundation of China(Grant No.11331006)supported by National Natural Science Foundation of China(Grant Nos.11301180 and 11771085)supported by National Research Foundation of Korea(Grant No.NRF2017R1A2B4008388)。
文摘A double Ore extension was introduced by Zhang and Zhang(2008)to study a class of ArtinShelter regular algebras.Here we give a definition of Poisson double extension which may be considered as an analogue of the double Ore extension,and show that algebras in a class of double Ore extensions are deformation quantizations of Poisson double extensions.We also investigate the modular derivations of Poisson double extensions and the relationship between Poisson double extensions and iterated Poisson polynomial extensions.Results are illustrated by examples.
