Aqueous rechargeable zinc ion batteries are regarded as a competitive alternative to lithium-ion batteries because of their distinct advantages of high security,high energy density,low cost,and environmental friendlin...Aqueous rechargeable zinc ion batteries are regarded as a competitive alternative to lithium-ion batteries because of their distinct advantages of high security,high energy density,low cost,and environmental friendliness.However,deep-seated problems including Zn dendrite and adverse side reactions severely impede the practical application.In this work,we proposed a freestanding Zn-electrolyte interfacial layer composed of multicapsular carbon fibers(MCFs)to regulate the plating/stripping behavior of Zn anodes.The versatile MCFs protective layer can uniformize the electric field and Zn^(2+)flux,meanwhile,reduce the deposition overpotentials,leading to high-quality and rapid Zn deposition kinetics.Furthermore,the bottom-up and uniform deposition of Zn on the Zn-MCFs interface endows long-term and high-capacity plating.Accordingly,the Zn@MCFs symmetric batteries can keep working up to 1500 h with 5 mAh cm^(−2).The feasibility of the MCFs interfacial layer is also convinced in Zn@MCFs||MnO_(2) batteries.Remarkably,the Zn@MCFs||α-MnO_(2)batteries deliver a high specific capacity of 236.1 mAh g^(−1)at 1 A g^(−1)with excellent stability,and maintain an exhilarating energy density of 154.3 Wh kg^(−1) at 33%depth of discharge in pouch batteries.展开更多
The recent advancements in thermoelectric materials are largely credited to two factors,namely established physical theories and advanced materials engineering methods.The developments in the physical theories have co...The recent advancements in thermoelectric materials are largely credited to two factors,namely established physical theories and advanced materials engineering methods.The developments in the physical theories have come a long way from the“phonon glass electron crystal”paradigm to the more recent band convergence and nanostructuring,which consequently results in drastic improvement in the thermoelectric figure of merit value.On the other hand,the progresses in materials fabrication methods and processing technologies have enabled the discovery of new physical mechanisms,hence further facilitating the emergence of high-performance thermoelectric materials.In recent years,many comprehensive review articles are focused on various aspects of thermoelectrics ranging from thermoelectric materials,physical mechanisms and materials process techniques in particular with emphasis on solid state reactions.While bottom-up approaches to obtain thermoelectric materials have widely been employed in thermoelectrics,comprehensive reviews on summarizing such methods are still rare.In this review,we will outline a variety of bottom-up strategies for preparing high-performance thermoelectric materials.In addition,state-of-art,challenges and future opportunities in this domain will be commented.展开更多
Detailed research on China's CO_(2) emission pathway of the 2030 peak and 2060 carbon neutrality goals is fundamental to promote China's climate change action.Previous studies on emission pathways have been ba...Detailed research on China's CO_(2) emission pathway of the 2030 peak and 2060 carbon neutrality goals is fundamental to promote China's climate change action.Previous studies on emission pathways have been based on long-term emission data or model analyses.However,few studies have achieved synergy and pathway optimization at both the micro and macro levels or focused on China's 2060 carbon neutrality goal,making it difficult to support the systematic management of national and regional emission pathways.In this study,we developed an integrated CO_(2) emission pathway model,the Chinese Academy of Environmental Planning Carbon Pathways 1.2 model,under China's climate change goals.Our pathway coupled the top-down and bottom-up approaches and conducted optimization analysis under social fairness and optimal cost conditions.The results provide a clear CO_(2) emission pathway and offer insights for implementing fine management of CO_(2) emissions at the national,regional,sectoral,and spatial gridded levels.展开更多
Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D ...Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D framework remains a tough challenge.To achieve a uniform bottom-up Li growth,a scheme involving Ag concentration gradient in 3 D PVDF framework(C-Ag/PVDF)is proposed.Ag nanoparticles with a concentration gradient induce an interface activity gradient in the 3 D framework,and this gradient feature is still maintained during the cycle.As a result,the C-Ag/PVDF framework delivers a long lifespan over 1800 h at a current density of 1 mA cm^(-2) with a capacity of 1 mAh cm^(-2),and shows an ultra-long life(>1300 h)even at a high current density of 4 mA cm^(-2) with a capacity of 4 mAh cm^(-2).The advantage of concentration gradient provides further insights into the optimal design of the 3 D framework for stable Li metal anode.展开更多
Ribosomes are abundant,large RNA-protein complexes that are the sites of all protein synthesis in cells.Defects in ribosomal proteins(RPs),including proteoforms arising from genetic variations,alternative splicing of ...Ribosomes are abundant,large RNA-protein complexes that are the sites of all protein synthesis in cells.Defects in ribosomal proteins(RPs),including proteoforms arising from genetic variations,alternative splicing of RNA transcripts,post-translational modifications and alterations of protein expression level,have been linked to a diverse range of diseases,including cancer and aging.Comprehensive characterization of ribosomal proteoforms is challenging but important for the discovery of potential disease biomarkers or protein targets.In the present work,using E.coli 70S RPs as an example,we first developed a top-down proteomics approach on a Waters Synapt G2 Si mass spectrometry(MS)system,and then applied it to the HeLa 80S ribosome.The results were complemented by a bottom-up approach.In total,50 out of 55 RPs were identified using the top-down approach.Among these,more than 30 RPs were found to have their N-terminal methionine removed.Additional modifications such as methylation,acetylation,and hydroxylation were also observed,and the modification sites were identified by bottomup MS.In a HeLa 80S ribosomal sample,we identified 98 ribosomal proteoforms,among which multiple truncated 80S ribosomal proteoforms were observed,the type of information which is often overlooked by bottom-up experiments.Although their relevance to diseases is not yet known,the integration of topdown and bottom-up proteomics approaches paves the way for the discovery of proteoform-specific disease biomarkers or targets.展开更多
The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device s...The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device stability.Here,we report a bottom-up holistic carrier management strategy induced synergistically by multiple chemical bonds to minimize bulk and interfacial energy losses for high-performance perovskite photovoltaics.4-trifluoromethyl-benzamidine hydrochloride(TBHCl)containing–CF_(3),amidine cation and Cl^(-)is in advance incorporated into SnO_(2)colloid solution to realize bottom-up modification.The synergistic effect of multiple functional groups and multiple-bond-induced chemical interaction are revealed theoretically and experimentally.F and Cl^(-)can passivate oxygen vacancy and/or undercoordinated Sn^(4+)defects by coordinating with Sn^(4+).The F can suppress cation migration and modulate crystallization via hydrogen bond with FA^(+),and can passivate lead defects by coordinating with Pb^(2+).The–NH_(2)–C=NH^(+)_(2)and Cl^(-)can passivate cation and anion vacancy defects through ionic bonds with perovskites,respectively.Through TBHCl modification,the suppression of agglomeration of SnO_(2)nanoparticles,bulk and interfacial defect passivation,and release of tensile strains of perovskite films are demonstrated,which resulted in a PCE enhancement from 21.28%to 23.40%and improved stability.With post-treatment,the efficiency is further improved to 23.63%.展开更多
This paper mainly deals with two mainstreams in teaching listening comprehension:bottom-up processing approach and top-down processing approach.In the first part of the essay the importance of listening comprehension ...This paper mainly deals with two mainstreams in teaching listening comprehension:bottom-up processing approach and top-down processing approach.In the first part of the essay the importance of listening comprehension in language learning will be demonstrated briefly.Then the author will go on to explore the nature of top-down and bottom-up approaches in teaching listening.Lastly,at the third part of the essay,the author shall try to discuss the possibility of applying these approaches into practice,that is,when and why one of them is more useful.Furthermore in this section,a more integrated view will be introduced.展开更多
Traditional approach to evaluate the impacts of climate change on the water resources systems always begins with downscaling general circulation models( GCMs) and proceeding back to the hydrological model. This approa...Traditional approach to evaluate the impacts of climate change on the water resources systems always begins with downscaling general circulation models( GCMs) and proceeding back to the hydrological model. This approach has some distinct disadvantages: 1) GCM must be downscaled; 2) different GCMs are difficult to be reconciled for a given climate change scenario;3) the uncertainty of GCMs is far from the requirement of the evaluation of climate change impacts. To overcome these limits of the traditional method,a new method termed as "bottom-up"was used for climate risk assessment that linked vulnerability assessment with climate information to assess the risk of climate change impacts on the Quabbin Reservoir,and United States under A2 scenario.The result shows that the risks are around 20% in 2006-2035 and 2036-2055,50% in 2066-2095.展开更多
Top-down and bottom-up processes are two popularly-used method in teaching listening,but each of them has deficiencies.This essay will attempt to demonstrate that both top-down process and bottom-up process are necess...Top-down and bottom-up processes are two popularly-used method in teaching listening,but each of them has deficiencies.This essay will attempt to demonstrate that both top-down process and bottom-up process are necessarily useful,and adopting them appropriately conduce to effective and efficient listening comprehension.The first section of this paper will critically examine the advantages and disadvantages of the two processes.It will then illustrate the benefit of employing them in an interactive way.展开更多
Designing product platform could be an effective and efficient solution for manufacturing firms. Product platforms enable firms to provide increased product variety for the marketplace with as little variety between p...Designing product platform could be an effective and efficient solution for manufacturing firms. Product platforms enable firms to provide increased product variety for the marketplace with as little variety between products as possible. Developed consumer products and modules within a firm can further be investigated to find out the possibility of product platform creation. A bottom-up method is proposed for module-based product platform through mapping, clustering and matching analysis. The framework and the parametric model of the method are presented, which consist of three steps:(1) mapping parameters from existing product families to functional modules,(2) clustering the modules within existing module families based on their parameters so as to generate module clusters, and selecting the satisfactory module clusters based on commonality, and(3) matching the parameters of the module clusters to the functional modules in order to capture platform elements. In addition, the parameter matching criterion and mismatching treatment are put forward to ensure the effectiveness of the platform process, while standardization and serialization of the platform element are presented. A design case of the belt conveyor is studied to demonstrate the feasibility of the proposed method.展开更多
Constructing specific structures from the bottom up with artificial units is an important interdisciplinary topic involving physics,chemistry,materials,and so on.In this work,we theoretically demonstrated the feasibil...Constructing specific structures from the bottom up with artificial units is an important interdisciplinary topic involving physics,chemistry,materials,and so on.In this work,we theoretically demonstrated the feasibility of using superatoms as building blocks to assemble a complex at atomic-level precision.By using a series of actinide-based endohedral metallofullerene(EMF)superatoms that can form one,two,three and four chemical bonds,a planar complex with intra-and inter-molecular interactions was assembled on the Au(111)surface.This complex is composed of two parts,containing ten and eight superatoms,respectively.The electronic structure analysis shows that the electron density inside each part is connected and the closed-shell electronic arrangement system is designed.There is also an obvious van der Waals boundary by physical adsorption between the two parts,and a stable complex is formed.Since this complex is realized by the first-principles calculations of quantum mechanics,our results help not only achieve atomic-level precision construction with artificial superatomic units but also maintain atomic-level functional properties.展开更多
A new algorithm for bottom-up saliency estimation is proposed.Based on the sparse coding model,a power spectral filter is proposed to eliminate the second-order residual correlation,which suppresses the global repeate...A new algorithm for bottom-up saliency estimation is proposed.Based on the sparse coding model,a power spectral filter is proposed to eliminate the second-order residual correlation,which suppresses the global repeated items effectively.In addition,aiming at modeling the mechanism of the human retina prior response to high-contrast stimuli,the effect of color context is considered.Experiments on the three publicly available databases and some psychophysical images show that the proposed model is comparable with the state-of-the-art saliency models,which not only highlights the salient objects in a complex environment but also pops up them uniformly.展开更多
基金supported by the National Natural Science Foundation of China(51901206)“the Fundamental Research Funds for the Central Universities”(2021QNA4003).
文摘Aqueous rechargeable zinc ion batteries are regarded as a competitive alternative to lithium-ion batteries because of their distinct advantages of high security,high energy density,low cost,and environmental friendliness.However,deep-seated problems including Zn dendrite and adverse side reactions severely impede the practical application.In this work,we proposed a freestanding Zn-electrolyte interfacial layer composed of multicapsular carbon fibers(MCFs)to regulate the plating/stripping behavior of Zn anodes.The versatile MCFs protective layer can uniformize the electric field and Zn^(2+)flux,meanwhile,reduce the deposition overpotentials,leading to high-quality and rapid Zn deposition kinetics.Furthermore,the bottom-up and uniform deposition of Zn on the Zn-MCFs interface endows long-term and high-capacity plating.Accordingly,the Zn@MCFs symmetric batteries can keep working up to 1500 h with 5 mAh cm^(−2).The feasibility of the MCFs interfacial layer is also convinced in Zn@MCFs||MnO_(2) batteries.Remarkably,the Zn@MCFs||α-MnO_(2)batteries deliver a high specific capacity of 236.1 mAh g^(−1)at 1 A g^(−1)with excellent stability,and maintain an exhilarating energy density of 154.3 Wh kg^(−1) at 33%depth of discharge in pouch batteries.
基金The authors acknowledge support from A*STAR’s Science and Engineering Research Council,PHAROS program on Hybrid Thermoelectrics for Ambient Applications(Grant Nos.:1527200019,1527200020 and 1527200021)Agritech program on Sustainable Hybrid Lighting System for Controlled Environment Agriculture:A19D9a0096.
文摘The recent advancements in thermoelectric materials are largely credited to two factors,namely established physical theories and advanced materials engineering methods.The developments in the physical theories have come a long way from the“phonon glass electron crystal”paradigm to the more recent band convergence and nanostructuring,which consequently results in drastic improvement in the thermoelectric figure of merit value.On the other hand,the progresses in materials fabrication methods and processing technologies have enabled the discovery of new physical mechanisms,hence further facilitating the emergence of high-performance thermoelectric materials.In recent years,many comprehensive review articles are focused on various aspects of thermoelectrics ranging from thermoelectric materials,physical mechanisms and materials process techniques in particular with emphasis on solid state reactions.While bottom-up approaches to obtain thermoelectric materials have widely been employed in thermoelectrics,comprehensive reviews on summarizing such methods are still rare.In this review,we will outline a variety of bottom-up strategies for preparing high-performance thermoelectric materials.In addition,state-of-art,challenges and future opportunities in this domain will be commented.
基金The research was funded by the project“An Emission Scenario Air Quality Model Based Study on the Evaluation of‘Dual Attainments’of Chinese City”[Grant number.72074154],supported by the National Natural Science Foundation of China.
文摘Detailed research on China's CO_(2) emission pathway of the 2030 peak and 2060 carbon neutrality goals is fundamental to promote China's climate change action.Previous studies on emission pathways have been based on long-term emission data or model analyses.However,few studies have achieved synergy and pathway optimization at both the micro and macro levels or focused on China's 2060 carbon neutrality goal,making it difficult to support the systematic management of national and regional emission pathways.In this study,we developed an integrated CO_(2) emission pathway model,the Chinese Academy of Environmental Planning Carbon Pathways 1.2 model,under China's climate change goals.Our pathway coupled the top-down and bottom-up approaches and conducted optimization analysis under social fairness and optimal cost conditions.The results provide a clear CO_(2) emission pathway and offer insights for implementing fine management of CO_(2) emissions at the national,regional,sectoral,and spatial gridded levels.
基金supported by the Fundamental Research Funds for the Central Universities,China(ZYGX2019Z008)the National Natural Science Foundation of China(52072061)the Open Fund of the Key Laboratory for Renewable Energy,Chinese Academy of Sciences,Beijing Key Laboratory for New Energy Materials and Devices。
文摘Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D framework remains a tough challenge.To achieve a uniform bottom-up Li growth,a scheme involving Ag concentration gradient in 3 D PVDF framework(C-Ag/PVDF)is proposed.Ag nanoparticles with a concentration gradient induce an interface activity gradient in the 3 D framework,and this gradient feature is still maintained during the cycle.As a result,the C-Ag/PVDF framework delivers a long lifespan over 1800 h at a current density of 1 mA cm^(-2) with a capacity of 1 mAh cm^(-2),and shows an ultra-long life(>1300 h)even at a high current density of 4 mA cm^(-2) with a capacity of 4 mAh cm^(-2).The advantage of concentration gradient provides further insights into the optimal design of the 3 D framework for stable Li metal anode.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.:91953102 and 81872836)Natural Science Foundation of Guangdong Province,China(Grant Nos.:2019A1515011265 and 2022A1515010965)+1 种基金the Fundamental Research Funds for Sun Yat-sen University,China(Grant No.:19ykzd26)Open Project Funding of the State Key Laboratory of Crop Stress Adaptation and Improvement(Grant No.:2020KF05).Huilin Li would like to thank the Pearl River Talent Recruitment Program for support.
文摘Ribosomes are abundant,large RNA-protein complexes that are the sites of all protein synthesis in cells.Defects in ribosomal proteins(RPs),including proteoforms arising from genetic variations,alternative splicing of RNA transcripts,post-translational modifications and alterations of protein expression level,have been linked to a diverse range of diseases,including cancer and aging.Comprehensive characterization of ribosomal proteoforms is challenging but important for the discovery of potential disease biomarkers or protein targets.In the present work,using E.coli 70S RPs as an example,we first developed a top-down proteomics approach on a Waters Synapt G2 Si mass spectrometry(MS)system,and then applied it to the HeLa 80S ribosome.The results were complemented by a bottom-up approach.In total,50 out of 55 RPs were identified using the top-down approach.Among these,more than 30 RPs were found to have their N-terminal methionine removed.Additional modifications such as methylation,acetylation,and hydroxylation were also observed,and the modification sites were identified by bottomup MS.In a HeLa 80S ribosomal sample,we identified 98 ribosomal proteoforms,among which multiple truncated 80S ribosomal proteoforms were observed,the type of information which is often overlooked by bottom-up experiments.Although their relevance to diseases is not yet known,the integration of topdown and bottom-up proteomics approaches paves the way for the discovery of proteoform-specific disease biomarkers or targets.
基金financially supported by the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074)the Natural Science Foundation of Chongqing(cstc2020jcyj-msxm X0629)。
文摘The defects from electron transport layer,perovskite layer and their interface would result in carrier nonradiative recombination losses.Poor buried interfacial contact is detrimental to charge extraction and device stability.Here,we report a bottom-up holistic carrier management strategy induced synergistically by multiple chemical bonds to minimize bulk and interfacial energy losses for high-performance perovskite photovoltaics.4-trifluoromethyl-benzamidine hydrochloride(TBHCl)containing–CF_(3),amidine cation and Cl^(-)is in advance incorporated into SnO_(2)colloid solution to realize bottom-up modification.The synergistic effect of multiple functional groups and multiple-bond-induced chemical interaction are revealed theoretically and experimentally.F and Cl^(-)can passivate oxygen vacancy and/or undercoordinated Sn^(4+)defects by coordinating with Sn^(4+).The F can suppress cation migration and modulate crystallization via hydrogen bond with FA^(+),and can passivate lead defects by coordinating with Pb^(2+).The–NH_(2)–C=NH^(+)_(2)and Cl^(-)can passivate cation and anion vacancy defects through ionic bonds with perovskites,respectively.Through TBHCl modification,the suppression of agglomeration of SnO_(2)nanoparticles,bulk and interfacial defect passivation,and release of tensile strains of perovskite films are demonstrated,which resulted in a PCE enhancement from 21.28%to 23.40%and improved stability.With post-treatment,the efficiency is further improved to 23.63%.
文摘This paper mainly deals with two mainstreams in teaching listening comprehension:bottom-up processing approach and top-down processing approach.In the first part of the essay the importance of listening comprehension in language learning will be demonstrated briefly.Then the author will go on to explore the nature of top-down and bottom-up approaches in teaching listening.Lastly,at the third part of the essay,the author shall try to discuss the possibility of applying these approaches into practice,that is,when and why one of them is more useful.Furthermore in this section,a more integrated view will be introduced.
基金National Natural Science Foundation of China(No.40971026)Key State Lab of Urban Water Resource and Environment,China(No.ES201109)+1 种基金National Science and Technology Infrastructure Program,China(No.2012BAC19B05-4)Natural Science Foundation of Jilin Province,China(No.20130101085JC)
文摘Traditional approach to evaluate the impacts of climate change on the water resources systems always begins with downscaling general circulation models( GCMs) and proceeding back to the hydrological model. This approach has some distinct disadvantages: 1) GCM must be downscaled; 2) different GCMs are difficult to be reconciled for a given climate change scenario;3) the uncertainty of GCMs is far from the requirement of the evaluation of climate change impacts. To overcome these limits of the traditional method,a new method termed as "bottom-up"was used for climate risk assessment that linked vulnerability assessment with climate information to assess the risk of climate change impacts on the Quabbin Reservoir,and United States under A2 scenario.The result shows that the risks are around 20% in 2006-2035 and 2036-2055,50% in 2066-2095.
文摘Top-down and bottom-up processes are two popularly-used method in teaching listening,but each of them has deficiencies.This essay will attempt to demonstrate that both top-down process and bottom-up process are necessarily useful,and adopting them appropriately conduce to effective and efficient listening comprehension.The first section of this paper will critically examine the advantages and disadvantages of the two processes.It will then illustrate the benefit of employing them in an interactive way.
基金Project(9140A18010210KG01)supported by the Departmental Pre-research Fund of China
文摘Designing product platform could be an effective and efficient solution for manufacturing firms. Product platforms enable firms to provide increased product variety for the marketplace with as little variety between products as possible. Developed consumer products and modules within a firm can further be investigated to find out the possibility of product platform creation. A bottom-up method is proposed for module-based product platform through mapping, clustering and matching analysis. The framework and the parametric model of the method are presented, which consist of three steps:(1) mapping parameters from existing product families to functional modules,(2) clustering the modules within existing module families based on their parameters so as to generate module clusters, and selecting the satisfactory module clusters based on commonality, and(3) matching the parameters of the module clusters to the functional modules in order to capture platform elements. In addition, the parameter matching criterion and mismatching treatment are put forward to ensure the effectiveness of the platform process, while standardization and serialization of the platform element are presented. A design case of the belt conveyor is studied to demonstrate the feasibility of the proposed method.
基金supported by the National Natural Science Foundation of China(Grant Nos.11974136,11674123,and 11374004)
文摘Constructing specific structures from the bottom up with artificial units is an important interdisciplinary topic involving physics,chemistry,materials,and so on.In this work,we theoretically demonstrated the feasibility of using superatoms as building blocks to assemble a complex at atomic-level precision.By using a series of actinide-based endohedral metallofullerene(EMF)superatoms that can form one,two,three and four chemical bonds,a planar complex with intra-and inter-molecular interactions was assembled on the Au(111)surface.This complex is composed of two parts,containing ten and eight superatoms,respectively.The electronic structure analysis shows that the electron density inside each part is connected and the closed-shell electronic arrangement system is designed.There is also an obvious van der Waals boundary by physical adsorption between the two parts,and a stable complex is formed.Since this complex is realized by the first-principles calculations of quantum mechanics,our results help not only achieve atomic-level precision construction with artificial superatomic units but also maintain atomic-level functional properties.
基金Supported by the China Postdoctoral Science Foundation(2011M500917)the Jiangsu Innovation Program for Graduate Education(CXLX11_0180)
文摘A new algorithm for bottom-up saliency estimation is proposed.Based on the sparse coding model,a power spectral filter is proposed to eliminate the second-order residual correlation,which suppresses the global repeated items effectively.In addition,aiming at modeling the mechanism of the human retina prior response to high-contrast stimuli,the effect of color context is considered.Experiments on the three publicly available databases and some psychophysical images show that the proposed model is comparable with the state-of-the-art saliency models,which not only highlights the salient objects in a complex environment but also pops up them uniformly.
