The phase behavior of water is a topic of perpetual interest due to its reinai kable anomalous properties and importance to biology,material science,geoscience,nanoscience,etc.It is predicted confined water at interfa...The phase behavior of water is a topic of perpetual interest due to its reinai kable anomalous properties and importance to biology,material science,geoscience,nanoscience,etc.It is predicted confined water at interface can exist in large amounts of crystalline or amorphous states.However,the experimental evidence of coexistence of liquid water phases at interface is still insufficient.Here,a special folding few-layers graphene film was elaborate prepared to form a hydrophobic/hydrophobic interface,which can provide a suited platform to study the structure and properties of confined liquid water.The real-space visualization of intercalated water layers phases at the folding interface is obtained using advanced atomic force microscopy(AFM).The folding graphene interface displays complicated internal interfacial characteristics.The intercalated water molecules present themselves as two phases,low-density liquid(LDL,solid-like)and high-density liquid(HDL,liquid-like),according to their specific mechanical properties taken in two multifrequency-AFM(MF-AFM)modes.Furthermore,the water molecules structural evolution is demonstrated in a series of continuous MF-AFM measurements.The work preliminary confirms the existence of two liquid phases of water in real space and will inspire further experimental work to deeply understanding their liquid dynamics behavior.展开更多
Safety is important to lithium ion battery materials. The thermal stability of LiFePOa/C-LiMn204 blended cathode materials is characterized by using TG, XRD, and SEM etc. The results show that LiFePO4/C-LiMn2O4 posses...Safety is important to lithium ion battery materials. The thermal stability of LiFePOa/C-LiMn204 blended cathode materials is characterized by using TG, XRD, and SEM etc. The results show that LiFePO4/C-LiMn2O4 possesses a worse thermal stability than pure spinel LiMn2O4 and pure olivine LiFePO4/C. When LiFePO4/C-LiMn2O4 blended cathode materials are sintered at 500℃ under Ar atmosphere, the sintered cathode materials emit O2, and appear impurity phases （Li3PO4, Fe2O3, Mn3O4）. It is deduced that some chemical reactions take place between different materials, which leads to a worse discharge specific capacity. LiFePO4/C-LiMn2O4 blended cathode materials, therefore, need to be managed and controlled strictly for the sake of ther- mal stability and safety.展开更多
The last 20 years have witnessed growing impacts of the topological concept on the branches of physics,including materials,electronics,photonics,and acoustics.Topology describes objects with some global invariant prop...The last 20 years have witnessed growing impacts of the topological concept on the branches of physics,including materials,electronics,photonics,and acoustics.Topology describes objects with some global invariant property under continuous deformation,which in mathematics could date back to the 17th century and mature in the 20th century.In physics,it successfully underpinned the physics of the Quantum Hall effect in 1984.To date,topology has been extensively applied to describe topological phases in acoustic metamaterials.As artificial structures,acoustic metamaterials could be well theoretically analyzed,on-demand designed,and easily fabricated by modern techniques,such as three-dimensional printing.Some new theoretical topological models were first discovered in acoustic metamaterials analogous to electronic counterparts,associated with novel effects for acoustics closer to applications.In this review,we focused on the concept of topology and its realization in airborne acoustic crystals,solid elastic phononic crystals,and surface acoustic wave systems.We also introduced emerging concepts of non-Hermitian,higher-order,and Floquet topological insulators in acoustics.It has been shown that the topology theory has such a powerful generality that among the disciplines from electron to photon and phonon,from electronic to photonics and acoustics,from acoustic topological theory to acoustic devices,could interact and be analogous to fertilize fantastic new ideas and prototype devices,which might find applications in acoustic engineering and noisevibration control engineering in the near future.展开更多
The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite...The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite, and the other the displacive transformation. It provides a coupled mechanism for the formation of bainite. With the numerical simulation results, a diffusion-induced nucleation and a diffusion-accompanied growth of displacive transformation were suggested. This theory can be helpful to over- throw the thermodynamic difficulty of displacive transformation above the Ms temperature, and also helpful to understand the Bs temperature, the partial supersaturation, the single variation of bainitic carbides, and the incomplete-reaction phenomenon of bainitic transformation, etc..展开更多
Two-dimensional(2D)materials have received tremendous attention because they possess a set of merits not available in bulk materials,such as large specific surface area,low energy barrier for electron transportation a...Two-dimensional(2D)materials have received tremendous attention because they possess a set of merits not available in bulk materials,such as large specific surface area,low energy barrier for electron transportation and short ion diffusion path.These advantages are desirable especially for the electrodes in electrochemical energy storage devices.MXenes,first synthesized in 2011 by etching their MAX phase precursors,have plural reasons to represent a new family of 2D materials.Their rich diversity in structure and composition together with the uncommon combination of good electrical conductivity and hydrophilicity makes themselves outstand in the whole 2D materials world.Based on these advantages,MXenes hold great promise for various technologically important applications,particularly in developing new energy storage techniques for advanced smart systems,such as portable and flexible electronics.There have been remarkable research achievements in the synthesis and application of MXene-based materials.While new synthesis routes being continuously reported,MXenes with new composition and novel structure have also been routinely discovered,which will undoubtedly help understand the fundamental properties and expand the application scope of MXenes.As for their energy storage-related applications,to cope with the intrinsic weakness of MXenes,many endeavors have been made by doping,structure-tuning and compositing with hybrid ingredients.In this review,the current status of MXenes synthesis and up-to-date progress of their applications in supercapacitors,metal-ion batteries and lithium sulfur batteries are summarized and discussed,and the typical work on the application of MXenes for the aforementioned three categories is respectively tabulated for reference and comparison.展开更多
Introducing transformation-induced plasticity(TRIP)effect into bulk metallic glass composites(BMGCs)is an effective route to improve their ductility and strain-hardening ability.Since the morphology and structure of t...Introducing transformation-induced plasticity(TRIP)effect into bulk metallic glass composites(BMGCs)is an effective route to improve their ductility and strain-hardening ability.Since the morphology and structure of the crystalline austenite phases responsible for the TRIP phenomenon are strongly dependent on the alloy composition and cooling rate during freezing,distinguishing the optimal cases from a vast variety of candidates is the primary task of exploring TRIP BMGCs.However,without a suitable theoretical guidance,the exploration of BMGCs is usually performed via the traditional trial-and-error route,making the BMGC development extremely time consuming and labor intensive.Here,we present a novel high-throughput strategy to accelerate the exploration process of TRIP BMGCs.The efficiency of this strategy was demonstrated on a well-studied Cu-Zr-Al alloy system.A screening library,comprised by121 cylindrical samples with different conditions,was rapidly prepared by laser additive manufacturing(LAM).The phases of the library were efficiently identified by micro-area X-ray diffraction(M-XRD)to screen the optimal compositions and cooling rates that precipitate only B2-Cu Zr phase.The distribution uniformity of the B2-Cu Zr phase was further evaluated based on digital image processing technology to screen the candidates of better ductility.The high-throughput results are in good agreement with the previous casting investigations of discrete samples,confirming the validity of the present high-throughput strategy.展开更多
基金the Ministry of Science and Technology(MOST)of China(No.2016YFA0200700)the National Natural Science Foun-dation of China(NSFC)(Nos.21622304,61674045,and 11604063)+1 种基金the Strategic Priority Research Program,the Key Research Program of Frontier Sciences and Instrument Developing Project of Chinese Academy of Sciences(CAS)(Nos.XDB30000000,QYZDB-SSW-SYS031,and YZ201418)Z.H.Cheng was supported by Distinguished Technical Talents Project and Youth Innovation Promotion Association CAS,the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China(No.18XNLG01).
文摘The phase behavior of water is a topic of perpetual interest due to its reinai kable anomalous properties and importance to biology,material science,geoscience,nanoscience,etc.It is predicted confined water at interface can exist in large amounts of crystalline or amorphous states.However,the experimental evidence of coexistence of liquid water phases at interface is still insufficient.Here,a special folding few-layers graphene film was elaborate prepared to form a hydrophobic/hydrophobic interface,which can provide a suited platform to study the structure and properties of confined liquid water.The real-space visualization of intercalated water layers phases at the folding interface is obtained using advanced atomic force microscopy(AFM).The folding graphene interface displays complicated internal interfacial characteristics.The intercalated water molecules present themselves as two phases,low-density liquid(LDL,solid-like)and high-density liquid(HDL,liquid-like),according to their specific mechanical properties taken in two multifrequency-AFM(MF-AFM)modes.Furthermore,the water molecules structural evolution is demonstrated in a series of continuous MF-AFM measurements.The work preliminary confirms the existence of two liquid phases of water in real space and will inspire further experimental work to deeply understanding their liquid dynamics behavior.
基金supported by National Natural Science Foundation of China(Grant No.51364021)Natural Science Foundation of Yunnan Province(Grant No.2014FA025)+1 种基金Innovative Research Team in University of Ministry of Education of China(Grant No.IRT1250)Academician free exploration project of Yunnan Province(Grant No.14051600)
文摘Safety is important to lithium ion battery materials. The thermal stability of LiFePOa/C-LiMn204 blended cathode materials is characterized by using TG, XRD, and SEM etc. The results show that LiFePO4/C-LiMn2O4 possesses a worse thermal stability than pure spinel LiMn2O4 and pure olivine LiFePO4/C. When LiFePO4/C-LiMn2O4 blended cathode materials are sintered at 500℃ under Ar atmosphere, the sintered cathode materials emit O2, and appear impurity phases （Li3PO4, Fe2O3, Mn3O4）. It is deduced that some chemical reactions take place between different materials, which leads to a worse discharge specific capacity. LiFePO4/C-LiMn2O4 blended cathode materials, therefore, need to be managed and controlled strictly for the sake of ther- mal stability and safety.
基金National Key Research and Development Program of China,Grant/Award Numbers:2021YFB3801801,2018YFA0306200Natural Science Foundation of China,Grant/Award Numbers:11890702,51721001,51732006,52022038,11874196。
文摘The last 20 years have witnessed growing impacts of the topological concept on the branches of physics,including materials,electronics,photonics,and acoustics.Topology describes objects with some global invariant property under continuous deformation,which in mathematics could date back to the 17th century and mature in the 20th century.In physics,it successfully underpinned the physics of the Quantum Hall effect in 1984.To date,topology has been extensively applied to describe topological phases in acoustic metamaterials.As artificial structures,acoustic metamaterials could be well theoretically analyzed,on-demand designed,and easily fabricated by modern techniques,such as three-dimensional printing.Some new theoretical topological models were first discovered in acoustic metamaterials analogous to electronic counterparts,associated with novel effects for acoustics closer to applications.In this review,we focused on the concept of topology and its realization in airborne acoustic crystals,solid elastic phononic crystals,and surface acoustic wave systems.We also introduced emerging concepts of non-Hermitian,higher-order,and Floquet topological insulators in acoustics.It has been shown that the topology theory has such a powerful generality that among the disciplines from electron to photon and phonon,from electronic to photonics and acoustics,from acoustic topological theory to acoustic devices,could interact and be analogous to fertilize fantastic new ideas and prototype devices,which might find applications in acoustic engineering and noisevibration control engineering in the near future.
文摘The Ginzbury-Landau theory for bainitic transformation was devised, which contains two first-order phase transformations, one being reconstructive represented by the diffusional proeutectoidal precipitation of ferrite, and the other the displacive transformation. It provides a coupled mechanism for the formation of bainite. With the numerical simulation results, a diffusion-induced nucleation and a diffusion-accompanied growth of displacive transformation were suggested. This theory can be helpful to over- throw the thermodynamic difficulty of displacive transformation above the Ms temperature, and also helpful to understand the Bs temperature, the partial supersaturation, the single variation of bainitic carbides, and the incomplete-reaction phenomenon of bainitic transformation, etc..
基金supported by the Grants of National Natural Science Foundation of China(52171033 and 51731004)Natural Science Foundation of Jiangsu Province(BK20201283)Zhishan Youth Scholar Program of SEU.
文摘Two-dimensional(2D)materials have received tremendous attention because they possess a set of merits not available in bulk materials,such as large specific surface area,low energy barrier for electron transportation and short ion diffusion path.These advantages are desirable especially for the electrodes in electrochemical energy storage devices.MXenes,first synthesized in 2011 by etching their MAX phase precursors,have plural reasons to represent a new family of 2D materials.Their rich diversity in structure and composition together with the uncommon combination of good electrical conductivity and hydrophilicity makes themselves outstand in the whole 2D materials world.Based on these advantages,MXenes hold great promise for various technologically important applications,particularly in developing new energy storage techniques for advanced smart systems,such as portable and flexible electronics.There have been remarkable research achievements in the synthesis and application of MXene-based materials.While new synthesis routes being continuously reported,MXenes with new composition and novel structure have also been routinely discovered,which will undoubtedly help understand the fundamental properties and expand the application scope of MXenes.As for their energy storage-related applications,to cope with the intrinsic weakness of MXenes,many endeavors have been made by doping,structure-tuning and compositing with hybrid ingredients.In this review,the current status of MXenes synthesis and up-to-date progress of their applications in supercapacitors,metal-ion batteries and lithium sulfur batteries are summarized and discussed,and the typical work on the application of MXenes for the aforementioned three categories is respectively tabulated for reference and comparison.
基金the National Natural Science Foundation of China under Grant Nos.51671042,51671043,51675074 and 51971047the project of Liaoning Province’s“rejuvenating Liaoning talents plan”under Grant No.XLYC1907046+4 种基金the Program for Innovative Talents of Liaoning Higher Education Institution under Grant No.LR2018014the Natural Science Foundation of Liaoning Province under Grant No.2019-MS-034the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science under Grant No.2019JH3/30100032Dalian Science and Technology Innovation Fund Project under Grant No.2018J11CY027the Dalian Support Plan for Innovation of High-level Talents under Grant No.2018RQ07。
文摘Introducing transformation-induced plasticity(TRIP)effect into bulk metallic glass composites(BMGCs)is an effective route to improve their ductility and strain-hardening ability.Since the morphology and structure of the crystalline austenite phases responsible for the TRIP phenomenon are strongly dependent on the alloy composition and cooling rate during freezing,distinguishing the optimal cases from a vast variety of candidates is the primary task of exploring TRIP BMGCs.However,without a suitable theoretical guidance,the exploration of BMGCs is usually performed via the traditional trial-and-error route,making the BMGC development extremely time consuming and labor intensive.Here,we present a novel high-throughput strategy to accelerate the exploration process of TRIP BMGCs.The efficiency of this strategy was demonstrated on a well-studied Cu-Zr-Al alloy system.A screening library,comprised by121 cylindrical samples with different conditions,was rapidly prepared by laser additive manufacturing(LAM).The phases of the library were efficiently identified by micro-area X-ray diffraction(M-XRD)to screen the optimal compositions and cooling rates that precipitate only B2-Cu Zr phase.The distribution uniformity of the B2-Cu Zr phase was further evaluated based on digital image processing technology to screen the candidates of better ductility.The high-throughput results are in good agreement with the previous casting investigations of discrete samples,confirming the validity of the present high-throughput strategy.
