MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivi...MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs.展开更多
Urbanization has resulted in a significant degra-dation of soil quality,subjecting plants to persistent abiotic stressors such as heavy metal pollution,salinization,and drought.UDP-glycosyltransferases(UGTs)participat...Urbanization has resulted in a significant degra-dation of soil quality,subjecting plants to persistent abiotic stressors such as heavy metal pollution,salinization,and drought.UDP-glycosyltransferases(UGTs)participate in protein glycosylation,secondary metabolite synthesis,and detoxification of exogenous toxic substances.Iris sanguinea Donn ex Hornem exhibits a high degree of resistance to various abiotic stressors.To enhance the plant’s response to adversity,a novel glycosyltransferase belonging to the UGT78 family,encoding flavonoid 3-O-glucosyltransferase(UF3GT),was cloned from the monocot species I.san-guinea.Compared with the control group,overexpression of IsUGT78 enhanced sensitivity to cadmium stress,while showing no significant impact under NaCl and d-sorbitol treatments.Under cadmium treatment,arabidopsis exoge-nously transformed with the IsUGT78 gene possessed lower germination,fresh weight,root length,and chlorophyll con-tent and increased malondialdehyde content than the wild type arabidopsis.In addition,metabolomics in leaves led to the identification of 299 flavonoid metabolites,eight and 127 which were significantly up-and down-regulated,respec-tively,in the transgenic plants.Of note,all eight upregulated flavonoid compounds were glycosylated.Given that arabi-dopsis,which exogenously expresses the IsUGT78 gene,has reduced resistance to cadmium,IsUGT78 may lead to a reduced ability to cope with cadmium stress.展开更多
Two parallel carbon-membrane aerated biofilm reactors were operated at well-defined conditions to investigate the effect of substrate COD/N ratios on the performance and microbial community structure of the bioreactor...Two parallel carbon-membrane aerated biofilm reactors were operated at well-defined conditions to investigate the effect of substrate COD/N ratios on the performance and microbial community structure of the bioreactor. Results showed that at substrate COD/N of 5, organic and nitrogen could be eliminated simultaneously, and COD removal degree, nitrification and denitrification efficiency reached 85%, 93% and 92%, respectively. With increasing substrate COD/N ratios, the specific oxygen utilization rates of nitrifying bacteria in biofilm were found to decrease, indicating that nitrifying population became less dominant. At substrate COD/N ratio of 6, excessive heterotrophs inhibited the activity of nitrifying bacteria greatly and thus led to poor nitrification process. With the help of fluorescence in situ hybridization （FISH）, Nitrosomonas and Nitrosospira were identified as dominant ammonia-oxidizing bacteria in the biofilm at substrate COD/N of 0, whereas only Nitrosospira were detected in the biofilm at COD/N ratio of 5. Nitrospira were present as dominant nitrite-oxidizing bacteria in our study. Confocal laser scanning microscopy images revealed that at substrate COD/N ratio of 0 nitrifying bacteria existed throughout the biofilm and that at COD/N ratio of 5 they were mainly distributed in the inner layer of biofilm.展开更多
An exhaustive study has been conducted to investigate span-based models for the joint entity and relation extraction task.However,these models sample a large number of negative entities and negative relations during t...An exhaustive study has been conducted to investigate span-based models for the joint entity and relation extraction task.However,these models sample a large number of negative entities and negative relations during the model training,which are essential but result in grossly imbalanced data distributions and in turn cause suboptimal model performance.In order to address the above issues,we propose a two-phase paradigm for the span-based joint entity and relation extraction,which involves classifying the entities and relations in the first phase,and predicting the types of these entities and relations in the second phase.The two-phase paradigm enables our model to significantly reduce the data distribution gap,including the gap between negative entities and other entities,aswell as the gap between negative relations and other relations.In addition,we make the first attempt at combining entity type and entity distance as global features,which has proven effective,especially for the relation extraction.Experimental results on several datasets demonstrate that the span-based joint extraction model augmented with the two-phase paradigm and the global features consistently outperforms previous state-ofthe-art span-based models for the joint extraction task,establishing a new standard benchmark.Qualitative and quantitative analyses further validate the effectiveness the proposed paradigm and the global features.展开更多
Bimetallic sulfides,integrating the merits of individual components,are ideal structures for efficient electrocatalysis.However,for bimetallic sulfides including metal sulfide heterojunctions(MSH)and singlephase bimet...Bimetallic sulfides,integrating the merits of individual components,are ideal structures for efficient electrocatalysis.However,for bimetallic sulfides including metal sulfide heterojunctions(MSH)and singlephase bimetallic sulfides(SBS),it is still unclear about which one has better catalytic activity toward reversible oxygen catalysis and its difference on catalytic mechanism.In this work,we demonstrate a bimetallic sulfide electrocatalyst that could transform from metal sulfide heterojunction(CoS/FeS)to single-phase bimetallic sulfide(CoFeS_(2))through a facile temperature control strategy.The single-phase bimetallic sulfide(CoFeS_(2))affords high intrinsic activity,fast reaction kinetics and superior durability toward oxygen evolution reaction(OER)and oxygen reduction reaction(ORR).Density functional theory(DFT)simulations reveal that the(CoFeS_(2))has homogeneous electron distribution of the CoFeS_(2)structure,improves the central energy level of d band,and optimizes the O*and OOH*intermediate and efficiently reduces the energy barrier of the reaction rate-determining step(RDS).The assembled rechargeable zincair battery is more stable than the Pt/C and IrO_(2) assemblies due to the excellent electrocatalytic activity and stability of CoFeS_(2)/NC,suggesting that it has potential for use in practical applications.展开更多
The novel electronic properties of bilayer graphene can be fine-tuned via twisting,which may induce flat bands around the Fermi level with nontrivial topology.In general,the band structure of such twisted bilayer grap...The novel electronic properties of bilayer graphene can be fine-tuned via twisting,which may induce flat bands around the Fermi level with nontrivial topology.In general,the band structure of such twisted bilayer graphene(TBG)can be theoretically obtained by using first-principles calculations,tight-binding method,or continuum model,which are either computationally demanding or parameters dependent.In this work,by using the sure independence screening sparsifying operator method,we propose a physically interpretable three-dimensional(3D)descriptor which can be utilized to readily obtain theΓ-point gap of TBG at arbitrary twist angles and different interlayer spacings.The strong predictive power of the descriptor is demonstrated by a high Pearson coefficient of 99%for both the training and testing data.To go further,we adopt the neural network algorithm to accurately probe the flat bands of TBG at various twist angles,which can accelerate the study of strong correlation physics associated with such a fundamental characteristic,especially for those systems with a larger number of atoms in the unit cell.展开更多
Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified W...Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.展开更多
Microplastics(MPs)have garnered increasing research attentions due to their ubiquitous presence in the environment and consequential impacts on both ecosystems and human health.Wastewater treatment plants(WWTPs)are id...Microplastics(MPs)have garnered increasing research attentions due to their ubiquitous presence in the environment and consequential impacts on both ecosystems and human health.Wastewater treatment plants(WWTPs)are identified as major sources of MPs in aquatic environments,as they receive anthropogenic MPs from household and industrial sewer networks.Based on treated wastewater samples collected in October 2018 from a WWTP in Hangzhou City,China,the MP transport into the Qiantang River before heading into Hangzhou Bay,East China Sea,was investigated.To determine the abundance and characteristics of MPs,the quantities of MPs released into the environment from the WWTP in different treatment stages were estimated,and their migration was simulated using numerical modeling techniques.Results show that the abundance of MPs in the effluent of the WWTP was 1.3 pieces/L,with a daily discharge of 7.6×10^(8)pieces of MPs into the Qiantang River.Polyether sulfone(PES),rayon,and polyethylene terephthalate(PET)were identified from MPs,being dominated by polypropylene(PP).MPs predominantly displayed fibrous and fragmented shapes.Household laundering and plastic product usage were major sources of MPs,with mechanical wear during treatment potentially contributing to the transformation from primary to secondary MPs.After 45 days of transport simulation,a high abundance zone of MPs was observed in the southern region of Hangzhou Bay,with its diffusion range being influenced by the combined effects of river runoff and tides.The spatial distribution range was significantly greater during the spring tide compared to that in the neap tide,and there were varying degrees of MP accumulation in the upper reaches of the wastewater outlet as runoff decreased.This study integrated the emissions and transport of MPs from WWTPs to estuarine rivers,thereby providing valuable scientific guidance for future regional control measures and ecological risk assessments of MPs.展开更多
A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphe...A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphene,respectively,as precursor in eutectic Na Cl-KCl molten salt at 800–900℃for 2–3 h.Higher temperature and longer duration are more beneficial for TiC preparation.In addition,mechanism of TiC formation was investigated by linear scan voltammetry.Results indicate that nanocrystalline TiC is in-situ synthesized by reaction between Ti atoms,which come from disproportionation reaction of Ti(Ⅱ)species in the molten salt,and C atoms on the surface of carbon sources.展开更多
Phosphor materials have been rapidly developed in the past decades. Developing phosphors with desired properties including strong luminescence intensity and long lifetime has attracted widespread attention. Herein, we...Phosphor materials have been rapidly developed in the past decades. Developing phosphors with desired properties including strong luminescence intensity and long lifetime has attracted widespread attention. Herein, we show that hetero-valence ion doping can serve as a potent strategy to manipulate luminescence in persistent phosphors by controlling disorder in the host lattice. Specifically, spinel phosphor Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr is developed by doping ZnGa_2O_4:Cr with tetravalent Ge^(^(4+)).Compared to the original ZnGa_2O_4:Cr, the doped Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr possesses significantly enhanced persistent luminescence intensity and prolonged decay time. Rietveld refinements show that Ge^(4+)enters into octahedral sites to substitute Ga^(3+), which leads to the co-substitution of Ga^(3+) by Zn^(2+) for charge compensation. The hetero-valence substitution of Ga^(3+) by Ge^(4+)and Zn^(2+) enriches the charged defects in Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr, making it possible to trap large amounts of charge carriers within the defects during excitation. Electron paramagnetic resonance measurement further confirms that the amount of Cr^(3+) neighboring charged defects increases with Ge^(4+)doping. Thus charge carriers released from defects can readily combine with the neighboring Cr^(3+) to produce bright persistent luminescence after excitation ceases. The hetero-valence ion doping strategy can further be employed to develop many other phosphors and contributes to lighting, photocatalysis and bioimaging.展开更多
A simple method to synthesize high-content ternary carbide Ti3AlC2 nanoparticles from Ti,Al,and C starting elemental powders without ball milling in NaCl–KCl molten salt was reported.The effects of mass ratio of the ...A simple method to synthesize high-content ternary carbide Ti3AlC2 nanoparticles from Ti,Al,and C starting elemental powders without ball milling in NaCl–KCl molten salt was reported.The effects of mass ratio of the salt to starting materials,temperature,reaction time,and Al molar ratio on preparation of Ti3AlC2 were investigated.The Ti3AlC2 formation is dramatically influenced by temperature and mass ratio of the salt to raw materials:a higher temperature and higher mass ratio of the salt to raw materials are more preferable for Ti3AlC2 powder formation.Homogenous Ti3AlC2 powder with particle size of■nm is synthesized by 3Ti/Al/2C starting elemental powders in NaCl–KCl molten salt at 900℃for 10 h,950℃for 5h,or 1000℃for 2h,respectively,when the mass ratio of the salt to 3Ti/Al/2C starting materials is 10:1.展开更多
Over the past few decades,molecular dynamics simulations and first-principles calculations have become two major approaches to predict the lattice thermal conductivity(κ_(L)),which are however limited by insufficient...Over the past few decades,molecular dynamics simulations and first-principles calculations have become two major approaches to predict the lattice thermal conductivity(κ_(L)),which are however limited by insufficient accuracy and high computational cost,respectively.To overcome such inherent disadvantages,machine learning(ML)has been successfully used to accurately predictκL in a high-throughput style.In this review,we give some introductions of recent ML works on the direct and indirect prediction ofκL,where the derivations and applications of data-driven models are discussed in details.A brief summary of current works and future perspectives are given in the end.展开更多
Topological materials are a new and rapidly expanding class of quantum matter. To date, identification of the topological nature of a given compound material demands specific determination of the appropriate topologic...Topological materials are a new and rapidly expanding class of quantum matter. To date, identification of the topological nature of a given compound material demands specific determination of the appropriate topological invariant through detailed electronic structure calculations. Here we present an efficient criterion that allows ready screening of potential topological materials, using topological insulators as prototypical examples. The criterion is inherently tied to the band inversion induced by spin-orbit coupling,and is uniquely defined by a minimal number of two elemental physical properties of the constituent elements: the atomic number and Pauling electronegativity. The validity and predictive power of the criterion is demonstrated by rationalizing many known topological insulators and potential candidates in the tetradymite and half-Heusler families, and the underlying design principle is naturally also extendable to predictive discoveries of other classes of topological materials.展开更多
Transition metal nitrides(TMNs),including titanium nitride(TiN),exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries(LIBs).Regrettably,the absence of simple synthesis methods ...Transition metal nitrides(TMNs),including titanium nitride(TiN),exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries(LIBs).Regrettably,the absence of simple synthesis methods restricts their further development.Herein,a facile and low-cost molten salt synthesis strategy was proposed to prepare carbon-anchored TiN nanoparticles as an advanced anode material for LIBs with high rate capabilities.This nanosized TiN obtained is∼5 nm in size and well-distributed onto carbon plates,which could release a reversible capacity of∼381.5 mAh g^(−1)at 0.1 A g^(−1)after 250 cycles and∼141.5 mAh g^(−1)at 1.0 A g^(−1)after 1000 cycles.Furthermore,it was confirmed that the conversion reaction between TiN and Li-ions happened during the electrochemical reaction process,resulting in the formation of Li_(3)N and Ti.This unique microstructure attributed from TiN nanoparticles anchored by carbon could support the structural volume during cycling.This work highlights the method superiority of TiN prepared via a molten salt synthesis strategy as an anode for LIBs with impressive rate performances.展开更多
Accurate evaluation of lattice thermal conductivity is usually a tough task from the theoretical side,especially for alloyed systems with fractional stoichiometry.Using the tetradymite family as a prototypical class o...Accurate evaluation of lattice thermal conductivity is usually a tough task from the theoretical side,especially for alloyed systems with fractional stoichiometry.Using the tetradymite family as a prototypical class of examples,we propose a reliable approach for rapid prediction on the lattice thermal conductivity at arbitrary composition by utilizing the concept of configurational entropy.Instead of performing time-consuming first-principles calculations,the lattice thermal conductivities of any alloyed tetradymites can be readily obtained from a few samples with integer stoichiometry.The strong predictive power is demonstrated by good agreement between our results and those reported experimentally.In principle,such an effective method can be applicable to any other material families,which is very beneficial for high-throughput design of systems with desired thermal conductivity.展开更多
It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier re...It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier relaxation time,which is usually a rough task due to the complicated scattering mechanisms.Previous works using the simple deformation potential theory or considering complete electron-phonon coupling are,however,restricted to small systems.By adopting a data-driven method named SISSO(Sure Independence Screening and Sparsifying Operator)with the training data obtained via deformation potential theory,we propose an efficient and physically interpretable descriptor to evaluate the relaxation time,using tetradymites as prototypical examples.Without any input from first-principles calculations,the descriptor contains only several elemental properties of the constituent atoms,and could be utilized to quickly and reliably predict the carrier relaxation time of a substantial number of tetradymites with arbitrary stoichiometry.展开更多
It has now become recognized that the electron-phonon coupling(EPC)may play an important role in governing the phonon transport,especially for metallic and semiconducting systems at high carrier concentration.Here we ...It has now become recognized that the electron-phonon coupling(EPC)may play an important role in governing the phonon transport,especially for metallic and semiconducting systems at high carrier concentration.Here we focus on the Weyl semimetals TaAs and NbAs and give a comparative study on their phonon transport properties by explicitly including the EPC in first-principles calculations.It is found that the lattice thermal conductivities of both systems are significantly reduced by the EPC,which is more pronounced for the TaAs compared with the NbAs at the same carrier concentration.Detailed analysis indicates that the TaAs exhibits smaller EPC phonon relaxation time,as characterized by stronger EPC strength which is associated with larger deformation potential constant and Born effective charge.Moreover,we see that the TaAs exhibits obviously larger overlap between the EPC relaxation time and that from intrinsic phonon-phonon scattering,which could further reduce the lattice thermal conduc-tivity.Our work not only highlights the vital importance of EPC in accurately predicting the phonon transport behaviors,but also offers a simple alternative to evaluate the EPC strength of various material systems.展开更多
Solid phase gene extraction(SPGE)was developed for in situ and rapid RNA extraction to enable the quantifi-cation of gene expression(Scherp and Hasenstein 2008).By inserting a pretreated probe directly into plant cell...Solid phase gene extraction(SPGE)was developed for in situ and rapid RNA extraction to enable the quantifi-cation of gene expression(Scherp and Hasenstein 2008).By inserting a pretreated probe directly into plant cells or tissues,it allowed fast RNA extraction that is suitable for spatiotemporal profiling of gene expression and fast screening of transformants during the process of devel-oping genetically modified plants(Nestorova et al.2017;Hasenstein et al.2023).展开更多
基金supported by the Basic Scientific Research Funds for Colleges and Universities affiliated to Hebei Province(JST2022005)Thanks are given to the financial support from the National Natural Science Foundation of China(22005099).
文摘MXenes are a family of two-dimensional(2D)layered transition metal carbides/nitrides that show promising potential for energy storage applications due to their high-specific surface areas,excellent electron conductivity,good hydrophilicity,and tunable terminations.Among various types of MXenes,Ti_(3)C_(2)T_(x) is the most widely studied for use in capacitive energy storage applications,especially in supercapacitors(SCs).However,the stacking and oxidation of MXene sheets inevitably lead to a significant loss of electrochemically active sites.To overcome such challenges,carbon materials are frequently incorporated into MXenes to enhance their electrochemical properties.This review introduces the common strategies used for synthesizing Ti_(3)C_(2)T_(x),followed by a comprehensive overview of recent developments in Ti_(3)C_(2)T_(x)/carbon composites as electrode materials for SCs.Ti_(3)C_(2)T_(x)/carbon composites are categorized based on the dimensions of carbons,including 0D carbon dots,1D carbon nanotubes and fibers,2D graphene,and 3D carbon materials(activated carbon,polymer-derived carbon,etc.).Finally,this review also provides a perspective on developing novel MXenes/carbon composites as electrodes for application in SCs.
基金supported by the Science and Technology Basic Resources Investigation Program of China(2019FY100500)the Fundamental Research Funds for the Central Universities(2572023CT18)the National Science Foundation(31670344).
文摘Urbanization has resulted in a significant degra-dation of soil quality,subjecting plants to persistent abiotic stressors such as heavy metal pollution,salinization,and drought.UDP-glycosyltransferases(UGTs)participate in protein glycosylation,secondary metabolite synthesis,and detoxification of exogenous toxic substances.Iris sanguinea Donn ex Hornem exhibits a high degree of resistance to various abiotic stressors.To enhance the plant’s response to adversity,a novel glycosyltransferase belonging to the UGT78 family,encoding flavonoid 3-O-glucosyltransferase(UF3GT),was cloned from the monocot species I.san-guinea.Compared with the control group,overexpression of IsUGT78 enhanced sensitivity to cadmium stress,while showing no significant impact under NaCl and d-sorbitol treatments.Under cadmium treatment,arabidopsis exoge-nously transformed with the IsUGT78 gene possessed lower germination,fresh weight,root length,and chlorophyll con-tent and increased malondialdehyde content than the wild type arabidopsis.In addition,metabolomics in leaves led to the identification of 299 flavonoid metabolites,eight and 127 which were significantly up-and down-regulated,respec-tively,in the transgenic plants.Of note,all eight upregulated flavonoid compounds were glycosylated.Given that arabi-dopsis,which exogenously expresses the IsUGT78 gene,has reduced resistance to cadmium,IsUGT78 may lead to a reduced ability to cope with cadmium stress.
基金supported by the National Science Council of China (No.50578023)
文摘Two parallel carbon-membrane aerated biofilm reactors were operated at well-defined conditions to investigate the effect of substrate COD/N ratios on the performance and microbial community structure of the bioreactor. Results showed that at substrate COD/N of 5, organic and nitrogen could be eliminated simultaneously, and COD removal degree, nitrification and denitrification efficiency reached 85%, 93% and 92%, respectively. With increasing substrate COD/N ratios, the specific oxygen utilization rates of nitrifying bacteria in biofilm were found to decrease, indicating that nitrifying population became less dominant. At substrate COD/N ratio of 6, excessive heterotrophs inhibited the activity of nitrifying bacteria greatly and thus led to poor nitrification process. With the help of fluorescence in situ hybridization （FISH）, Nitrosomonas and Nitrosospira were identified as dominant ammonia-oxidizing bacteria in the biofilm at substrate COD/N of 0, whereas only Nitrosospira were detected in the biofilm at COD/N ratio of 5. Nitrospira were present as dominant nitrite-oxidizing bacteria in our study. Confocal laser scanning microscopy images revealed that at substrate COD/N ratio of 0 nitrifying bacteria existed throughout the biofilm and that at COD/N ratio of 5 they were mainly distributed in the inner layer of biofilm.
基金supported by the National Key Research and Development Program[2020YFB1006302].
文摘An exhaustive study has been conducted to investigate span-based models for the joint entity and relation extraction task.However,these models sample a large number of negative entities and negative relations during the model training,which are essential but result in grossly imbalanced data distributions and in turn cause suboptimal model performance.In order to address the above issues,we propose a two-phase paradigm for the span-based joint entity and relation extraction,which involves classifying the entities and relations in the first phase,and predicting the types of these entities and relations in the second phase.The two-phase paradigm enables our model to significantly reduce the data distribution gap,including the gap between negative entities and other entities,aswell as the gap between negative relations and other relations.In addition,we make the first attempt at combining entity type and entity distance as global features,which has proven effective,especially for the relation extraction.Experimental results on several datasets demonstrate that the span-based joint extraction model augmented with the two-phase paradigm and the global features consistently outperforms previous state-ofthe-art span-based models for the joint extraction task,establishing a new standard benchmark.Qualitative and quantitative analyses further validate the effectiveness the proposed paradigm and the global features.
基金supported by the National Natural Science Foundation of China(21805051 and 21875048)the Outstanding Youth Project of Guangdong Natural Science Foundation(2020B1515020028)+1 种基金the Yangcheng Scholars Research Project of Guangzhou(201831820)the Science and Technology Research Project of Guangzhou(202002010007,202102020376,202201020214)。
文摘Bimetallic sulfides,integrating the merits of individual components,are ideal structures for efficient electrocatalysis.However,for bimetallic sulfides including metal sulfide heterojunctions(MSH)and singlephase bimetallic sulfides(SBS),it is still unclear about which one has better catalytic activity toward reversible oxygen catalysis and its difference on catalytic mechanism.In this work,we demonstrate a bimetallic sulfide electrocatalyst that could transform from metal sulfide heterojunction(CoS/FeS)to single-phase bimetallic sulfide(CoFeS_(2))through a facile temperature control strategy.The single-phase bimetallic sulfide(CoFeS_(2))affords high intrinsic activity,fast reaction kinetics and superior durability toward oxygen evolution reaction(OER)and oxygen reduction reaction(ORR).Density functional theory(DFT)simulations reveal that the(CoFeS_(2))has homogeneous electron distribution of the CoFeS_(2)structure,improves the central energy level of d band,and optimizes the O*and OOH*intermediate and efficiently reduces the energy barrier of the reaction rate-determining step(RDS).The assembled rechargeable zincair battery is more stable than the Pt/C and IrO_(2) assemblies due to the excellent electrocatalytic activity and stability of CoFeS_(2)/NC,suggesting that it has potential for use in practical applications.
基金the National Natural Science Foundation of China(Grant No.62074114)。
文摘The novel electronic properties of bilayer graphene can be fine-tuned via twisting,which may induce flat bands around the Fermi level with nontrivial topology.In general,the band structure of such twisted bilayer graphene(TBG)can be theoretically obtained by using first-principles calculations,tight-binding method,or continuum model,which are either computationally demanding or parameters dependent.In this work,by using the sure independence screening sparsifying operator method,we propose a physically interpretable three-dimensional(3D)descriptor which can be utilized to readily obtain theΓ-point gap of TBG at arbitrary twist angles and different interlayer spacings.The strong predictive power of the descriptor is demonstrated by a high Pearson coefficient of 99%for both the training and testing data.To go further,we adopt the neural network algorithm to accurately probe the flat bands of TBG at various twist angles,which can accelerate the study of strong correlation physics associated with such a fundamental characteristic,especially for those systems with a larger number of atoms in the unit cell.
基金supported by Hengyang City,Hunan Province Science and Technology Innovation Project(No.202250045319)the National Natural Science Foundation of China(Nos.11375084,21808125)the Scientific Research Planning Project of Jilin Provincial Education Department(No.JJKH20241249KJ)。
文摘Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.
基金Supported by the National Natural Science Foundation of China(No.42107268)the“Digital+”Discipline Construction Management Project of Zhejiang Gongshang University(No.SZJ2022A008)。
文摘Microplastics(MPs)have garnered increasing research attentions due to their ubiquitous presence in the environment and consequential impacts on both ecosystems and human health.Wastewater treatment plants(WWTPs)are identified as major sources of MPs in aquatic environments,as they receive anthropogenic MPs from household and industrial sewer networks.Based on treated wastewater samples collected in October 2018 from a WWTP in Hangzhou City,China,the MP transport into the Qiantang River before heading into Hangzhou Bay,East China Sea,was investigated.To determine the abundance and characteristics of MPs,the quantities of MPs released into the environment from the WWTP in different treatment stages were estimated,and their migration was simulated using numerical modeling techniques.Results show that the abundance of MPs in the effluent of the WWTP was 1.3 pieces/L,with a daily discharge of 7.6×10^(8)pieces of MPs into the Qiantang River.Polyether sulfone(PES),rayon,and polyethylene terephthalate(PET)were identified from MPs,being dominated by polypropylene(PP).MPs predominantly displayed fibrous and fragmented shapes.Household laundering and plastic product usage were major sources of MPs,with mechanical wear during treatment potentially contributing to the transformation from primary to secondary MPs.After 45 days of transport simulation,a high abundance zone of MPs was observed in the southern region of Hangzhou Bay,with its diffusion range being influenced by the combined effects of river runoff and tides.The spatial distribution range was significantly greater during the spring tide compared to that in the neap tide,and there were varying degrees of MP accumulation in the upper reaches of the wastewater outlet as runoff decreased.This study integrated the emissions and transport of MPs from WWTPs to estuarine rivers,thereby providing valuable scientific guidance for future regional control measures and ecological risk assessments of MPs.
基金supported financially by the National Natural Science Foundation of China(Nos.51671204 and 51501205).
文摘A high-efficiency method is developed to in-situ synthesize nanocrystalline TiC powders,nanorods,and nanosheets by using equimolar ratio of Ti powder and acetylene black,multiwalled carbon nanotubes(MWCNTs),and graphene,respectively,as precursor in eutectic Na Cl-KCl molten salt at 800–900℃for 2–3 h.Higher temperature and longer duration are more beneficial for TiC preparation.In addition,mechanism of TiC formation was investigated by linear scan voltammetry.Results indicate that nanocrystalline TiC is in-situ synthesized by reaction between Ti atoms,which come from disproportionation reaction of Ti(Ⅱ)species in the molten salt,and C atoms on the surface of carbon sources.
基金supported by the National Key R&D Program of China (2017YFA0208000)the National Natural Science Foundation of China (21675120, 21325104)the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Phosphor materials have been rapidly developed in the past decades. Developing phosphors with desired properties including strong luminescence intensity and long lifetime has attracted widespread attention. Herein, we show that hetero-valence ion doping can serve as a potent strategy to manipulate luminescence in persistent phosphors by controlling disorder in the host lattice. Specifically, spinel phosphor Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr is developed by doping ZnGa_2O_4:Cr with tetravalent Ge^(^(4+)).Compared to the original ZnGa_2O_4:Cr, the doped Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr possesses significantly enhanced persistent luminescence intensity and prolonged decay time. Rietveld refinements show that Ge^(4+)enters into octahedral sites to substitute Ga^(3+), which leads to the co-substitution of Ga^(3+) by Zn^(2+) for charge compensation. The hetero-valence substitution of Ga^(3+) by Ge^(4+)and Zn^(2+) enriches the charged defects in Zn(Ga_(1-x)Zn_x)(Ga_(1-x)Ge_x)O_4:Cr, making it possible to trap large amounts of charge carriers within the defects during excitation. Electron paramagnetic resonance measurement further confirms that the amount of Cr^(3+) neighboring charged defects increases with Ge^(4+)doping. Thus charge carriers released from defects can readily combine with the neighboring Cr^(3+) to produce bright persistent luminescence after excitation ceases. The hetero-valence ion doping strategy can further be employed to develop many other phosphors and contributes to lighting, photocatalysis and bioimaging.
基金supported financially by the National Natural Science Foundation of China(No.51501205).
文摘A simple method to synthesize high-content ternary carbide Ti3AlC2 nanoparticles from Ti,Al,and C starting elemental powders without ball milling in NaCl–KCl molten salt was reported.The effects of mass ratio of the salt to starting materials,temperature,reaction time,and Al molar ratio on preparation of Ti3AlC2 were investigated.The Ti3AlC2 formation is dramatically influenced by temperature and mass ratio of the salt to raw materials:a higher temperature and higher mass ratio of the salt to raw materials are more preferable for Ti3AlC2 powder formation.Homogenous Ti3AlC2 powder with particle size of■nm is synthesized by 3Ti/Al/2C starting elemental powders in NaCl–KCl molten salt at 900℃for 10 h,950℃for 5h,or 1000℃for 2h,respectively,when the mass ratio of the salt to 3Ti/Al/2C starting materials is 10:1.
基金We thank financial support from the National Natural Science Foundation of China(Grant No.62074114).
文摘Over the past few decades,molecular dynamics simulations and first-principles calculations have become two major approaches to predict the lattice thermal conductivity(κ_(L)),which are however limited by insufficient accuracy and high computational cost,respectively.To overcome such inherent disadvantages,machine learning(ML)has been successfully used to accurately predictκL in a high-throughput style.In this review,we give some introductions of recent ML works on the direct and indirect prediction ofκL,where the derivations and applications of data-driven models are discussed in details.A brief summary of current works and future perspectives are given in the end.
基金financial support from the National Natural Science Foundation of China (11574236, 51671193, and 61434002)support from the National Science Fund for Distinguished Young Scholars (No. 51725103)
文摘Topological materials are a new and rapidly expanding class of quantum matter. To date, identification of the topological nature of a given compound material demands specific determination of the appropriate topological invariant through detailed electronic structure calculations. Here we present an efficient criterion that allows ready screening of potential topological materials, using topological insulators as prototypical examples. The criterion is inherently tied to the band inversion induced by spin-orbit coupling,and is uniquely defined by a minimal number of two elemental physical properties of the constituent elements: the atomic number and Pauling electronegativity. The validity and predictive power of the criterion is demonstrated by rationalizing many known topological insulators and potential candidates in the tetradymite and half-Heusler families, and the underlying design principle is naturally also extendable to predictive discoveries of other classes of topological materials.
基金This work is supported by National Natural Science Foundation of China(No.51671204)Guangdong Basic and Applied Basic Research Foundation,China(No.2019A1515110825).
文摘Transition metal nitrides(TMNs),including titanium nitride(TiN),exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries(LIBs).Regrettably,the absence of simple synthesis methods restricts their further development.Herein,a facile and low-cost molten salt synthesis strategy was proposed to prepare carbon-anchored TiN nanoparticles as an advanced anode material for LIBs with high rate capabilities.This nanosized TiN obtained is∼5 nm in size and well-distributed onto carbon plates,which could release a reversible capacity of∼381.5 mAh g^(−1)at 0.1 A g^(−1)after 250 cycles and∼141.5 mAh g^(−1)at 1.0 A g^(−1)after 1000 cycles.Furthermore,it was confirmed that the conversion reaction between TiN and Li-ions happened during the electrochemical reaction process,resulting in the formation of Li_(3)N and Ti.This unique microstructure attributed from TiN nanoparticles anchored by carbon could support the structural volume during cycling.This work highlights the method superiority of TiN prepared via a molten salt synthesis strategy as an anode for LIBs with impressive rate performances.
基金We thank financial support from the National Natural Science Foundation of China(Grant Nos.62074114,51772220,and 12004368).
文摘Accurate evaluation of lattice thermal conductivity is usually a tough task from the theoretical side,especially for alloyed systems with fractional stoichiometry.Using the tetradymite family as a prototypical class of examples,we propose a reliable approach for rapid prediction on the lattice thermal conductivity at arbitrary composition by utilizing the concept of configurational entropy.Instead of performing time-consuming first-principles calculations,the lattice thermal conductivities of any alloyed tetradymites can be readily obtained from a few samples with integer stoichiometry.The strong predictive power is demonstrated by good agreement between our results and those reported experimentally.In principle,such an effective method can be applicable to any other material families,which is very beneficial for high-throughput design of systems with desired thermal conductivity.
基金We thank financial support from the National Natural Science Foundation(Grant Nos.51772220 and 62074114).
文摘It has been demonstrated that many promising thermoelectric materials,such as tetradymite compounds are also threedimensional topological insulators.In both cases,a fundamental question is the evaluation of carrier relaxation time,which is usually a rough task due to the complicated scattering mechanisms.Previous works using the simple deformation potential theory or considering complete electron-phonon coupling are,however,restricted to small systems.By adopting a data-driven method named SISSO(Sure Independence Screening and Sparsifying Operator)with the training data obtained via deformation potential theory,we propose an efficient and physically interpretable descriptor to evaluate the relaxation time,using tetradymites as prototypical examples.Without any input from first-principles calculations,the descriptor contains only several elemental properties of the constituent atoms,and could be utilized to quickly and reliably predict the carrier relaxation time of a substantial number of tetradymites with arbitrary stoichiometry.
基金support from the National Natural Science Foundation(Grant Nos.62074114,51772220).
文摘It has now become recognized that the electron-phonon coupling(EPC)may play an important role in governing the phonon transport,especially for metallic and semiconducting systems at high carrier concentration.Here we focus on the Weyl semimetals TaAs and NbAs and give a comparative study on their phonon transport properties by explicitly including the EPC in first-principles calculations.It is found that the lattice thermal conductivities of both systems are significantly reduced by the EPC,which is more pronounced for the TaAs compared with the NbAs at the same carrier concentration.Detailed analysis indicates that the TaAs exhibits smaller EPC phonon relaxation time,as characterized by stronger EPC strength which is associated with larger deformation potential constant and Born effective charge.Moreover,we see that the TaAs exhibits obviously larger overlap between the EPC relaxation time and that from intrinsic phonon-phonon scattering,which could further reduce the lattice thermal conduc-tivity.Our work not only highlights the vital importance of EPC in accurately predicting the phonon transport behaviors,but also offers a simple alternative to evaluate the EPC strength of various material systems.
基金supported by the National Science Foundation(31670344)the Fundamental Research Funds for the Central Universities(2572023CT18)+3 种基金the Natural Fund Project of Heilongjiang Province(LH2020C044)National Science Foundation,31670344Fundamental Research Funds for the Central Universities,2572023CT18Natural Fund Project of Heilongjiang Province,LH2020C044。
文摘Solid phase gene extraction(SPGE)was developed for in situ and rapid RNA extraction to enable the quantifi-cation of gene expression(Scherp and Hasenstein 2008).By inserting a pretreated probe directly into plant cells or tissues,it allowed fast RNA extraction that is suitable for spatiotemporal profiling of gene expression and fast screening of transformants during the process of devel-oping genetically modified plants(Nestorova et al.2017;Hasenstein et al.2023).
