This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key area...This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key areas:developing a high-quality digital talent training program for civil engineering;assembling diverse resources to create a digital,multi-scenario open learning environment that encompasses teaching,research,and practical training for civil engineering undergraduates;piloting innovative digital teaching models for civil engineering undergraduates;crafting a new model for digital resource provision,utilizing self-developed and specialized resources;devising assessment methods and ongoing improvement strategies based on the achievement of students’digital competencies;and devising a new,three-dimensional,multi-modal teaching evaluation system through intelligent data capture and analysis.展开更多
Pyrrolidine-2,5-dione and maleimide are important scaffolds of many organic substances, and their derivatives are now attracting more and more interests from researchers in organic synthesis, medicinal chemistry, and ...Pyrrolidine-2,5-dione and maleimide are important scaffolds of many organic substances, and their derivatives are now attracting more and more interests from researchers in organic synthesis, medicinal chemistry, and drug development. Tosyloxy (-OTs) group is an important functional group widely used in organic synthesis, because it can be readily prepared from alcohols and is an excellent leaving group. However, surprisingly, substances bearing tosyloxy groups on pyrrolidine-2,5-dione or maleimide scaffolds are very rare. In this study, we discovered that, when treated with TsCl/Et3N,?trans-3,4-dihydroxypyrrolidine-2,5- dione will eliminate a TsOH molecule to form monotosyloxymaleimide. Thermodynamic and kinetic factors affecting this reaction were investigated by theoretical computation using density functional theory (DFT), and the possible reaction mechanism was proposed based on the computation results. Our results showed that tosylates of trans -3,4-dihydroxypyrrolidine- 2,5-dione, either monotosylate or ditosylate, are thermodynamically instable and may spontaneously convert to maleimides. This knowledge could be useful in understanding the properties of pyrrolidine-2,5-diones and maleimides, as well as the related organic synthesis.展开更多
Purpose:As scientific resources are widely distributed,researchers often have difficulties in acquiring information from different individual sources.This paper intends to present a new approach to construct a subject...Purpose:As scientific resources are widely distributed,researchers often have difficulties in acquiring information from different individual sources.This paper intends to present a new approach to construct a subject-knowledge-based integration platform which was carried out by the Institute of Software,Chinese Academy of Sciences(ISCAS).Our aim is to use technique tools to strengthen the library service by combining a variety of information service resources with knowledge tools.Design/methodology/approach:Based on the analysis of users’ needs,we established a collaborative team across ISCAS Library,National Science Library of CAS(NSL CAS),and ISCAS’ research groups or research labs.With the service tools developed by ISCAS Library,we embedded other multipurpose utility tools of knowledge integration into the platform as to make full use of software tools in knowledge integration,knowledge fusion,and intelligent push of library services to end users.Findings:With a hard effort of the construction team,the ISCAS subject group platform(hereinafter as ISCAS Platform) has integrated such information resources as institutional repository(IR) of ISCAS,open resources from websites and subject resources of computer sciences.Up to date,ISCAS platform can provide integrated information services including data collection for computer science and intelligent generation of citation reports,by means of embedding self-developed discovering tools for domain experts and subject content,and generation tools for scientific citation reports.Research limitations:Knowledge organization need be further improved in the ISCAS subject group platform.In addition,functions for academic exchanges need be maximized as to meet the individual demands of researchers for library services at the Platform.Practical implications:Since we Platform has been put into use through the Library website of the ISCAS in June 2012,many academic libraries from both domestic universities and CAS institutes have showed their strong interest for our self-developed tools,among which more than 10 cooperation partnerships have been formed.Originality/value:Through self-developed service tools and the integration of multiple-type resources,our Platform has solved such key problems as timely access and update of the trusted resources from a third party,and the rapid fusion and extension of library resources while establishing subject knowledge environment.So the ISCAS library can provide a flexible customization of library services according to the need of different users.展开更多
What is already known about this topic?Antimony(Sb)has been identified as a new neurotoxicant that impacts neurological functions in animal studies.However,its effects on the human population remain unknown.What is ad...What is already known about this topic?Antimony(Sb)has been identified as a new neurotoxicant that impacts neurological functions in animal studies.However,its effects on the human population remain unknown.What is added by this report?The study reveals that there is an association between exposure to Sb and a higher incidence of cognitive impairment in older adults.The dose-response curve demonstrates that the risk of cognitive impairment consistently increased with higher levels of Sb exposure without a discernible threshold.What are the implications for public health practice?Reducing exposure to Sb may have a beneficial effect in delaying or preventing the onset of cognitive impairment.This intervention has the potential to significantly decrease the disease burden associated with cognitive impairment,ultimately contributing to social development.展开更多
As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been...As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been extensively used in GIS equipment fault detection.However,the X-ray image of GIS is blurred,which is not conducive to the detection of tiny defects.Thus,a super-resolution method for GIS X-ray images based on multi-scale context transformers is proposed in this study,namely MCTSR.Firstly,a second-order image degradation model is introduced to generate GIS X-ray lowresolution images that more closely resemble the real world.Secondly,a contextual transformer gate module is constructed to improve attention to tiny defects in GIS X-ray images.Thirdly,a U-Net discriminator network based on multi-scale contextual transformers is intended to enrich the information of the generated images.Finally,the proposed discriminator is combined with the existing generator to compose a superresolution method applicable to GIS X-ray images.The experimental results demonstrate that the method outperforms other methods in peak signal-to-noise ratio and structural similarity on the constructed GIS X-ray image dataset.In addition,the output image of the proposed method facilitates the subsequent defect detection.展开更多
Summary What is already known about this topic?Limited evidence on healthy longevity was provided in the world,and no studies investigated the fractions of healthy longevity attributed to modifiable factors.What is ad...Summary What is already known about this topic?Limited evidence on healthy longevity was provided in the world,and no studies investigated the fractions of healthy longevity attributed to modifiable factors.What is added by this report?Incidences of longevity and healthy longevity in China are provided.It reveals that the total weighted population attributable fractions for lifestyles and all modifiable factors were 32.8% and 83.7% for longevity,respectively,and 30.4% and 73.4% for healthy longevity,respectively.What are the implications for public health practice?China has a high potential for longevity and healthy longevity.Strategies may be targeted at education and residence in early life as well as healthy lifestyles,disease prevention,and functional optimization in late life.展开更多
The Na-based dual-ion batteries(NDIBs),combining the advantages of Na-ion batteries and dual-ion batteries,are attracting more attention due to their merits of abundant source,low cost and high energy density.However,...The Na-based dual-ion batteries(NDIBs),combining the advantages of Na-ion batteries and dual-ion batteries,are attracting more attention due to their merits of abundant source,low cost and high energy density.However,the main challenges faced by NDIBs are their low capacity and poor cycling.Herein,we report a new ion storage mechanism for high-performance NDIBs using amorphous carbon(AOMC)as cathode.Unlike the graphite carbon that can only accommodate the PF6-anion(typical DIB system),the AOMC herein can both accommodate Na+cation and PF6-anion due to its amorphous feature,which is conceptually new dual-ion system for achieving much higher capacity.Ex-situ X-ray photoelectron spectroscopy,X-ray diffraction and Raman studies reveal that the disordered carbon in the AOMC can be transformed to the partial graphitic stacking in short range,improving both capacity and cycling stability of NDIBs.As a consequence,the AOMC delivers a highly reversible storage capacity of 136 mAhg-1 for 800 cycles at a very high current density of 2.0 Ag-1,much higher than all the reported NDIBs.Such concept can be generalized to develop high-performance dual-ion full cell using sodium ion preintercalated materials as anode and AOMC as cathode.展开更多
Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfac...Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfactory performance in practice,owing to their intrinsically low conductivity,sluggish kinetics and volume expansion during the charge-discharge process.Herein,we demonstrate the synthesis of SnSe2 nanocrystals coupled with hierarchical porous carbon(SnSe2 NCs/C)microspheres for boosting SIBs in terms of capacity,rate ability and durability.The unique structure of SnSe2 NCs/C possesses several advantages,including inhibiting the agglomeration of SnSe2 nanoparticles,relieving the volume expansion,accelerating the diffusion kinetics of electrons/ions,enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite.As a result,the as-obtained SnSe2 NCs/C microspheres show a high reversible capacity(565 mA h g^-1 after 100 cycles at 100 mA g^-1),excellent rate capability,and long cycling life stability(363 mA h g^-1 at1 A g^-1 after 1000 cycles),which represent the best performances among the reported SIBs based on SnSe2-based anode materials.展开更多
Background:The heavy metals cadmium(Cd)and mercury(Hg)are known to be widespread environmental contaminants and high occupational exposure adversely affects the risk of chronic kidney disease(CKD).However,evidence fro...Background:The heavy metals cadmium(Cd)and mercury(Hg)are known to be widespread environmental contaminants and high occupational exposure adversely affects the risk of chronic kidney disease(CKD).However,evidence from epidemiological studies linking low Cd and Hg exposure(or non-industrial)to the risk of progression to CKD are conflicting.This study aimed to explore the association of low Cd and Hg exposure with the risk of CKD in Chinese adults aged≥80 years.Methods:The participants were recruited for the Healthy Aging and Biomarkers Cohort Study in 2017,an ongoing perspective survey conducted in longevity areas in China initially involving 3016 older adults.We used logistic regression models to estimate odds ratios(ORs)with 95%confidence intervals of CKD setting Cd and Hg as categorical variables.Logistic regression with restricted cubic spline was used to characterize a dose-response relationships between Cd or Hg concentrations and the risk of CKD in the study population.Results:The ORs for the risk of CKD comparing the fourth to the first quartile of blood Cd,blood Hg,urine Cd,and urine Hg were 1.77,1.57,2.03,and 1.50,respectively.Restricted cubic spline models showed that blood Cd and urine Hg were significantly linearly correlated with the risk of CKD,while blood Hg and urine Cd were non-linearly correlated with the risk of CKD with a steeper slope at concentrations<2.30μg/L and 3.30μg/g creatinine.Conclusions:Our findings suggest that even low Cd and Hg exposure(or non-industrial)were associated with increased risk of CKD in Chinese oldest old,although we did not find a significant multiplicative and additive interaction between Cd and Hg levels in relation to the risk of CKD.展开更多
Potassium-ion batteries(PIBs)show great potential in the application of large-scale energy storage devices due to the comparable high operating voltage with lithium-ion batteries and lower cost.Carbon-based materials ...Potassium-ion batteries(PIBs)show great potential in the application of large-scale energy storage devices due to the comparable high operating voltage with lithium-ion batteries and lower cost.Carbon-based materials are promising candidates as anodes for PIBs,for their low cost,high abundance,nontoxicity,environmental benignity,and sustainability.In this review,we will first discuss the potassium storage mechanisms of graphitic and defective carbon materials and carbon-based composites with various compositions and microstructures to comprehensively understand the potassium storage behavior.Then,several strategies based on heteroatoms doping,unique nanostructure design,and introduction of the conductive matrix to form composites are proposed to optimize the carbon-based materials and achieve high performance for PIBs.Finally,we conclude the existing challenges and perspectives for further development of carbon-based materials,which is believed to promote the practical application of PIBs in the future.展开更多
With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the car...With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the carpet cloak,which can hide an object on a reflecting plane,can operate over a broadband frequency range.However,the carpet cloaks experimentally realized thus far still have several limitations.For example,the quasi-conformal mapping carpet cloak leads to a lateral shift of the reflected light ray,while the birefringent carpet cloak only works for a specific polarization.In this work,we propose a conformal transformation scheme to tackle these two problems simultaneously.As an example,we design a mid-infrared carpet cloak in a silicon platform and demonstrate its polarization-insensitive property as well as the minimized lateral shift over a broad frequency band from 24 to 28.3 THz.展开更多
基金Chongqing Higher Education Teaching Reform Research Key Project(Project number:222128)Chongqing Three Gorges University Higher Education Research Project(Project number:JGSZH2203)+3 种基金Chongqing Education Science Planning Project(Project number:K23ZG2120245,K22ZS212737,K23YD2120100)Chongqing Three Gorges University First-Class Undergraduate Course“Principles of Steel Structures”Chongqing Three Gorges University Course Ideological and Political Demonstration Course“Principles of Steel Structures”Chongqing First-Class Undergraduate Course“Principles of Steel Structures”。
文摘This article examines the pathway to digital transformation and upgrading in undergraduate institutions,using the civil engineering program at Chongqing Three Gorges University as a case study,focusing on six key areas:developing a high-quality digital talent training program for civil engineering;assembling diverse resources to create a digital,multi-scenario open learning environment that encompasses teaching,research,and practical training for civil engineering undergraduates;piloting innovative digital teaching models for civil engineering undergraduates;crafting a new model for digital resource provision,utilizing self-developed and specialized resources;devising assessment methods and ongoing improvement strategies based on the achievement of students’digital competencies;and devising a new,three-dimensional,multi-modal teaching evaluation system through intelligent data capture and analysis.
文摘Pyrrolidine-2,5-dione and maleimide are important scaffolds of many organic substances, and their derivatives are now attracting more and more interests from researchers in organic synthesis, medicinal chemistry, and drug development. Tosyloxy (-OTs) group is an important functional group widely used in organic synthesis, because it can be readily prepared from alcohols and is an excellent leaving group. However, surprisingly, substances bearing tosyloxy groups on pyrrolidine-2,5-dione or maleimide scaffolds are very rare. In this study, we discovered that, when treated with TsCl/Et3N,?trans-3,4-dihydroxypyrrolidine-2,5- dione will eliminate a TsOH molecule to form monotosyloxymaleimide. Thermodynamic and kinetic factors affecting this reaction were investigated by theoretical computation using density functional theory (DFT), and the possible reaction mechanism was proposed based on the computation results. Our results showed that tosylates of trans -3,4-dihydroxypyrrolidine- 2,5-dione, either monotosylate or ditosylate, are thermodynamically instable and may spontaneously convert to maleimides. This knowledge could be useful in understanding the properties of pyrrolidine-2,5-diones and maleimides, as well as the related organic synthesis.
基金supported by the Chinese Academy of Sciences(Grant No.Y11006)
文摘Purpose:As scientific resources are widely distributed,researchers often have difficulties in acquiring information from different individual sources.This paper intends to present a new approach to construct a subject-knowledge-based integration platform which was carried out by the Institute of Software,Chinese Academy of Sciences(ISCAS).Our aim is to use technique tools to strengthen the library service by combining a variety of information service resources with knowledge tools.Design/methodology/approach:Based on the analysis of users’ needs,we established a collaborative team across ISCAS Library,National Science Library of CAS(NSL CAS),and ISCAS’ research groups or research labs.With the service tools developed by ISCAS Library,we embedded other multipurpose utility tools of knowledge integration into the platform as to make full use of software tools in knowledge integration,knowledge fusion,and intelligent push of library services to end users.Findings:With a hard effort of the construction team,the ISCAS subject group platform(hereinafter as ISCAS Platform) has integrated such information resources as institutional repository(IR) of ISCAS,open resources from websites and subject resources of computer sciences.Up to date,ISCAS platform can provide integrated information services including data collection for computer science and intelligent generation of citation reports,by means of embedding self-developed discovering tools for domain experts and subject content,and generation tools for scientific citation reports.Research limitations:Knowledge organization need be further improved in the ISCAS subject group platform.In addition,functions for academic exchanges need be maximized as to meet the individual demands of researchers for library services at the Platform.Practical implications:Since we Platform has been put into use through the Library website of the ISCAS in June 2012,many academic libraries from both domestic universities and CAS institutes have showed their strong interest for our self-developed tools,among which more than 10 cooperation partnerships have been formed.Originality/value:Through self-developed service tools and the integration of multiple-type resources,our Platform has solved such key problems as timely access and update of the trusted resources from a third party,and the rapid fusion and extension of library resources while establishing subject knowledge environment.So the ISCAS library can provide a flexible customization of library services according to the need of different users.
基金Supported by the National Natural Sciences Foundation of China(grant numbers 81872707,82025030,82003550,and 82230111).
文摘What is already known about this topic?Antimony(Sb)has been identified as a new neurotoxicant that impacts neurological functions in animal studies.However,its effects on the human population remain unknown.What is added by this report?The study reveals that there is an association between exposure to Sb and a higher incidence of cognitive impairment in older adults.The dose-response curve demonstrates that the risk of cognitive impairment consistently increased with higher levels of Sb exposure without a discernible threshold.What are the implications for public health practice?Reducing exposure to Sb may have a beneficial effect in delaying or preventing the onset of cognitive impairment.This intervention has the potential to significantly decrease the disease burden associated with cognitive impairment,ultimately contributing to social development.
基金Guangdong Science and Technology Innovation Strategy Special Funds Project,Grant/Award Number:pdjh2022b0545。
文摘As the core equipment of transmission and distribution hubs,the operational status of gas-insulated switchgear(GIS)is closely linked to the safety of the power system.Recently,X-ray digital imaging technology has been extensively used in GIS equipment fault detection.However,the X-ray image of GIS is blurred,which is not conducive to the detection of tiny defects.Thus,a super-resolution method for GIS X-ray images based on multi-scale context transformers is proposed in this study,namely MCTSR.Firstly,a second-order image degradation model is introduced to generate GIS X-ray lowresolution images that more closely resemble the real world.Secondly,a contextual transformer gate module is constructed to improve attention to tiny defects in GIS X-ray images.Thirdly,a U-Net discriminator network based on multi-scale contextual transformers is intended to enrich the information of the generated images.Finally,the proposed discriminator is combined with the existing generator to compose a superresolution method applicable to GIS X-ray images.The experimental results demonstrate that the method outperforms other methods in peak signal-to-noise ratio and structural similarity on the constructed GIS X-ray image dataset.In addition,the output image of the proposed method facilitates the subsequent defect detection.
基金Supported by the National Natural Science Foundation of China(grant numbers 82025030 and 81941023)Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences(grant number 2021-JKCS-028)Claude D.Pepper Older Americans Independence Centers grant(grant number 5P30 AG028716 from NIA).
文摘Summary What is already known about this topic?Limited evidence on healthy longevity was provided in the world,and no studies investigated the fractions of healthy longevity attributed to modifiable factors.What is added by this report?Incidences of longevity and healthy longevity in China are provided.It reveals that the total weighted population attributable fractions for lifestyles and all modifiable factors were 32.8% and 83.7% for longevity,respectively,and 30.4% and 73.4% for healthy longevity,respectively.What are the implications for public health practice?China has a high potential for longevity and healthy longevity.Strategies may be targeted at education and residence in early life as well as healthy lifestyles,disease prevention,and functional optimization in late life.
基金supported by the National Key Research and Development Program of China(2016YFB0100201)the National Natural Science Foundation of China(51671003)+2 种基金the start-up supports from Peking UniversityYoung Thousand Talented ProgramNational Innovation Zone of Defense Science and Technology of China(8205100116)
文摘The Na-based dual-ion batteries(NDIBs),combining the advantages of Na-ion batteries and dual-ion batteries,are attracting more attention due to their merits of abundant source,low cost and high energy density.However,the main challenges faced by NDIBs are their low capacity and poor cycling.Herein,we report a new ion storage mechanism for high-performance NDIBs using amorphous carbon(AOMC)as cathode.Unlike the graphite carbon that can only accommodate the PF6-anion(typical DIB system),the AOMC herein can both accommodate Na+cation and PF6-anion due to its amorphous feature,which is conceptually new dual-ion system for achieving much higher capacity.Ex-situ X-ray photoelectron spectroscopy,X-ray diffraction and Raman studies reveal that the disordered carbon in the AOMC can be transformed to the partial graphitic stacking in short range,improving both capacity and cycling stability of NDIBs.As a consequence,the AOMC delivers a highly reversible storage capacity of 136 mAhg-1 for 800 cycles at a very high current density of 2.0 Ag-1,much higher than all the reported NDIBs.Such concept can be generalized to develop high-performance dual-ion full cell using sodium ion preintercalated materials as anode and AOMC as cathode.
基金supported by the National Key R&D Research Program of China (2016YFB0100201)Beijing Natural Science Foundation (JQ18005)+2 种基金the National Natural Science Foundation of China (51671003, 21802003)China Postdoctoral Science Foundation (2019TQ0001)the start-up supports from Peking University and Young Thousand Talented Program
文摘Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfactory performance in practice,owing to their intrinsically low conductivity,sluggish kinetics and volume expansion during the charge-discharge process.Herein,we demonstrate the synthesis of SnSe2 nanocrystals coupled with hierarchical porous carbon(SnSe2 NCs/C)microspheres for boosting SIBs in terms of capacity,rate ability and durability.The unique structure of SnSe2 NCs/C possesses several advantages,including inhibiting the agglomeration of SnSe2 nanoparticles,relieving the volume expansion,accelerating the diffusion kinetics of electrons/ions,enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite.As a result,the as-obtained SnSe2 NCs/C microspheres show a high reversible capacity(565 mA h g^-1 after 100 cycles at 100 mA g^-1),excellent rate capability,and long cycling life stability(363 mA h g^-1 at1 A g^-1 after 1000 cycles),which represent the best performances among the reported SIBs based on SnSe2-based anode materials.
基金National Natural Sciences Foundation of China(No.82025030,82003550,81872707,and 81941023)Non-profit Central Research Institute Fund of Chinese Academy of Medical Sciences(No.2021-JKCS-028)
文摘Background:The heavy metals cadmium(Cd)and mercury(Hg)are known to be widespread environmental contaminants and high occupational exposure adversely affects the risk of chronic kidney disease(CKD).However,evidence from epidemiological studies linking low Cd and Hg exposure(or non-industrial)to the risk of progression to CKD are conflicting.This study aimed to explore the association of low Cd and Hg exposure with the risk of CKD in Chinese adults aged≥80 years.Methods:The participants were recruited for the Healthy Aging and Biomarkers Cohort Study in 2017,an ongoing perspective survey conducted in longevity areas in China initially involving 3016 older adults.We used logistic regression models to estimate odds ratios(ORs)with 95%confidence intervals of CKD setting Cd and Hg as categorical variables.Logistic regression with restricted cubic spline was used to characterize a dose-response relationships between Cd or Hg concentrations and the risk of CKD in the study population.Results:The ORs for the risk of CKD comparing the fourth to the first quartile of blood Cd,blood Hg,urine Cd,and urine Hg were 1.77,1.57,2.03,and 1.50,respectively.Restricted cubic spline models showed that blood Cd and urine Hg were significantly linearly correlated with the risk of CKD,while blood Hg and urine Cd were non-linearly correlated with the risk of CKD with a steeper slope at concentrations<2.30μg/L and 3.30μg/g creatinine.Conclusions:Our findings suggest that even low Cd and Hg exposure(or non-industrial)were associated with increased risk of CKD in Chinese oldest old,although we did not find a significant multiplicative and additive interaction between Cd and Hg levels in relation to the risk of CKD.
基金supported by the National Key R&D Program of China(Grant no.2017YFA0206701)the National Science Fund for Distinguished Young Scholars(Grant no.52025133)+1 种基金the Tencent Foundation through the XPLORER PRIZE,Beijing Natural Science Foundation(Grant no.JQ18005)the National Natural Science Foundation of China(Grant no.22002003).
文摘Potassium-ion batteries(PIBs)show great potential in the application of large-scale energy storage devices due to the comparable high operating voltage with lithium-ion batteries and lower cost.Carbon-based materials are promising candidates as anodes for PIBs,for their low cost,high abundance,nontoxicity,environmental benignity,and sustainability.In this review,we will first discuss the potassium storage mechanisms of graphitic and defective carbon materials and carbon-based composites with various compositions and microstructures to comprehensively understand the potassium storage behavior.Then,several strategies based on heteroatoms doping,unique nanostructure design,and introduction of the conductive matrix to form composites are proposed to optimize the carbon-based materials and achieve high performance for PIBs.Finally,we conclude the existing challenges and perspectives for further development of carbon-based materials,which is believed to promote the practical application of PIBs in the future.
基金Ministry of Education-Singapore(MOE 2018-T2-2-189(S),MOE2018-T2-1-176)National Research Foundation Singapore(NRF-CRP18-2017-02,NRFCRP22-2019-0006)+1 种基金Agency for Science,Technology and Research(A18A7b0058,A20E5c0095)National Natural Science Foundation of China(61871127).
文摘With the advent and rapid development of the transformation optics and metamaterials,invisibility cloaks have captivated much attention in recent years.While most cloaking schemes suffer from limited bandwidth,the carpet cloak,which can hide an object on a reflecting plane,can operate over a broadband frequency range.However,the carpet cloaks experimentally realized thus far still have several limitations.For example,the quasi-conformal mapping carpet cloak leads to a lateral shift of the reflected light ray,while the birefringent carpet cloak only works for a specific polarization.In this work,we propose a conformal transformation scheme to tackle these two problems simultaneously.As an example,we design a mid-infrared carpet cloak in a silicon platform and demonstrate its polarization-insensitive property as well as the minimized lateral shift over a broad frequency band from 24 to 28.3 THz.