Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation ...Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation of guest species in van der Waals(vdW)gap implemented for tunning properties has attracted much attention in recent years.We attempt to insert Ga atoms in the vdW gap between the Te layers in p-type Bi_(0.3)Sb_(1.7)Te_(3)(BST)for further improving thermoelectrics.The vdW-related defects(including extrinsic interstitial and intrinsic defects)induced by Ga intercalation can not only modulate the carrier concentration but also enhance the texture,thereby yielding excellent electrical properties,which are reflected in the power factor PF~4.43 mW·m^(-1)·K^(-2).Furthermore,the intercalation of Ga produces multi-scale lattice imperfections such as point defects,Te precipitations,and nanopores,realizing the low lattice thermal conductivity in BST-Ga samples.Ultimately,a peak zT~1.1 at 373 K is achieved in the BST-1%Ga sample and greatly improved by~22%compared to the pristine BST.The weak bonding of vdW interlayer interaction can boost the synergistic effect for advancing BST-based or other layered thermoelectrics.展开更多
AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and...AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and the high Ag_(Cr)deep-level defects limit the overall thermoelectric performance.Here,we successfully introduced Pb into Ag-deficient Ag_(0.97)CrSe_(2) alloys to tune the carrier concentration across a broad temperature range.The Pb^(2+) as an acceptor dopant preferentially occupies Cr sites,boosting the hole carrier concentration to 1.77×10^(19) cm^(-3) at room temperature.Furthermore,the Pb strongly inhibits the creation of intrinsic Ag_(Cr) defects,weakens the increased thermal excited ionization with the increasing temperature and slowed the rising trend of the carrier concentration.The designed carrier concentration matches the theoretically predicted optimized one over the entire temperature range,leading to a remarkable enhancement in power factor,especially the maximum power factor of ~500 μW·m^(-1)·K^(-2) at 750 K is superior to most previous results.Additionally,the abundant point defects promote phonon scattering,thus reducing the lattice thermal conductivity.As a result,the maximum figure of merit zT(~0.51 at 750 K) is achieved in Ag_(0.97)Cr_(0.995)Pb_(0.005)Se_(2).This work confirms the feasibility of manipulating deep-level defects to achieve temperature-dependent optimal carrier concentration and provides a valuable guidance for other thermoelectric materials.展开更多
Single-atom catalysts serve as a promising candidate to realize noble-metal-free electrocatalytic oxygen reduction in acid media.However,their poor stability under working conditions strictly restrains their practical...Single-atom catalysts serve as a promising candidate to realize noble-metal-free electrocatalytic oxygen reduction in acid media.However,their poor stability under working conditions strictly restrains their practical applications.Therefore,regeneration of their electrocatalytic activity is of great significance.Herein,the regeneration of a Fe-N-C single-atom catalyst is demonstrated to be feasible by a facile annealing regeneration strategy.The activity after regeneration recovers to that of the pristine electrocatalyst and surpasses the deactivated electrocatalyst.The regeneration mechanism is identified to be selfetching of the surface carbon layer and consequent exposure of the previously buried single-atom sites.Furthermore,the regeneration strategy is applicable to other single-atom catalysts.This work demonstrates the feasibility of regenerating oxygen reduction electrocatalysts and affords a pioneering approach to deal with rapid deactivation under working conditions.展开更多
Monoclinic SrAl_(2)Si_(2)O_(8) ceramics for Sr immobilization were prepared by a liquid-phase sintering method.The sintering temperature,mineral phase composition,microstructure,flexural strength,bulk density,and Sr i...Monoclinic SrAl_(2)Si_(2)O_(8) ceramics for Sr immobilization were prepared by a liquid-phase sintering method.The sintering temperature,mineral phase composition,microstructure,flexural strength,bulk density,and Sr ion leaching characteristics of the SrAl_(2)Si_(2)O_(8) ceramics were investigated.A crystalline monoclinic SrAl_(2)Si_(2)O_(8) phase formed through liquid-phase sintering at 1223 K.The introduction of four flux agents(B_(2)O_(3),CaO·2B_(2)O_(3),SrO·2B_(2)O_(3),and BaO·2B_(2)O_(3))to the SrAl_(2)Si_(2)O_(8) ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics.Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B_(2)O_(3) was the lowest,whereas that of Sr ions in the sample with flux agent BaO·2B_(2)O_(3) was the highest.These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics.Meanwhile,the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.展开更多
The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds w...The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).展开更多
Oxygen reduction reaction(ORR)constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells.However,the kinetics of ORR is very sluggish and thus highperforma...Oxygen reduction reaction(ORR)constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells.However,the kinetics of ORR is very sluggish and thus highperformance ORR electrocatalysts are highly regarded.Despite recent progress on minimizing the ORR halfwave potential as the current evaluation indicator,in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized.In this paper,a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation.Independent parameters regarding exchange current density,electron transfer number,and electrochemical active surface area can be respectively determined following the proposed method.This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.展开更多
Introduction: This study is on a creek located 45°42′18″N,122°39′41″W called Sahnon Creek.And after we finished all the experi- ments and tests which helped us to get some data and samples from the creek...Introduction: This study is on a creek located 45°42′18″N,122°39′41″W called Sahnon Creek.And after we finished all the experi- ments and tests which helped us to get some data and samples from the creek,it's time for us to get the result of these samples and data.Here are two questions we have to solve and展开更多
RNA-binding proteins(RBPs)are components of the post-transcriptional regulatory system,but their regulatory effects on complex traits remain unknown.Using an integrated strategy involving map-based cloning,functional ...RNA-binding proteins(RBPs)are components of the post-transcriptional regulatory system,but their regulatory effects on complex traits remain unknown.Using an integrated strategy involving map-based cloning,functional characterizations,and transcriptomic and population genomic analyses,we revealed that RBP-K(LOC_Os08g23120),RBP-A(LOC_Os11g41890),and RBP-J(LOC_Os10g33230)encode proteins that form an RBP-A-J-K complex that negatively regulates rice yield-related traits.Examinations of the RBP-A-J-K complex indicated RBP-K functions as a relatively non-specific RBP chaperone that enables RBP-A and RBP-J to function normally.Additionally,RBP-J most likely affects GA pathways,resulting in considerable increases in grain and panicle lengths,but decreases in grain width and thickness.In contrast,RBP-A negatively regulates the expression of genes most likely involved in auxin-regulated pathways controlling cell wall elongation and carbohydrate transport,with substantial effects on the rice grain filling process as well as grain length and weight.Evolutionarily,RBP-K is relatively ancient and highly conserved,whereas RBP-J and RBP-A are more diverse.Thus,the RBP-A-J-K complex may represent a typical functional model for many RBPs and protein complexes that function at transcriptional and post-transcriptional levels in plants and animals for increased functional consistency,efficiency,and versatility,as well as increased evolutionary potential.Our results clearly demonstrate the importance of RBP-mediated post-transcriptional regulation for the diversity of complex traits.Furthermore,rice grain yield and quality may be enhanced by introducing various complete or partial loss-of-function mutations to specific RBP genes using clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9 technology and by exploiting desirable natural tri-genic allelic combinations at the loci encoding the components of the RBP-A-J-K complex through marker-assisted selection.展开更多
Plant male reproductive development is a complex biological process, but the underlying mechanism is not well understood. Here, we characterized a rice （Oryza sativa L.） male sterile mutant. Based on map- based clon...Plant male reproductive development is a complex biological process, but the underlying mechanism is not well understood. Here, we characterized a rice （Oryza sativa L.） male sterile mutant. Based on map- based cloning and sequence analysis, we identified a 1,459-bp deletion in an adenosine triphosphate （ATP）-binding cassette （ABC） transporter gene, OsABCG15, causing abnormal anthers and male sterility. Therefore, we named this mutant osabcgl5. Expression analysis showed that OsABCG15 is expressed specifically in developmental anthers from stage 8 （meiosis II stage） to stage 10 （late microspore stage）. Two genes CYP704B2 and WDA1, involved in the biosynthesis of very-long-chain fatty acids for the establishment of the anther cuticle and pollen exine, were downregulated in osabcgl5 mutant, suggesting that OsABCG15 may play a key function in the processes related to sporopollenin biosynthesis or sporopollenin transfer from tapetal cells to anther Iocules. Consistently, histological analysis showed that osabcgl5 mutants developed obvious abnormality in postmeiotic tapetum degeneration, leading to rapid degredation of young microspores. The results suggest that OsABCG15 plays a critical role in exine formation and pollen development, similar to the homologous gene of AtABCG26 in Arabidopsis. This work is helpful to understand the regulatory network in rice anther development.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2022YFB3803900 and 2018YFA0702100)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。
文摘Tetradymite-structured chalcogenides,such as Bi_(2)Te_(3) and Sb_(2)Te_(3),are quasi-two-dimensional(2D)layered compounds,which are significant thermoelectric materials applied near room temperature.The intercalation of guest species in van der Waals(vdW)gap implemented for tunning properties has attracted much attention in recent years.We attempt to insert Ga atoms in the vdW gap between the Te layers in p-type Bi_(0.3)Sb_(1.7)Te_(3)(BST)for further improving thermoelectrics.The vdW-related defects(including extrinsic interstitial and intrinsic defects)induced by Ga intercalation can not only modulate the carrier concentration but also enhance the texture,thereby yielding excellent electrical properties,which are reflected in the power factor PF~4.43 mW·m^(-1)·K^(-2).Furthermore,the intercalation of Ga produces multi-scale lattice imperfections such as point defects,Te precipitations,and nanopores,realizing the low lattice thermal conductivity in BST-Ga samples.Ultimately,a peak zT~1.1 at 373 K is achieved in the BST-1%Ga sample and greatly improved by~22%compared to the pristine BST.The weak bonding of vdW interlayer interaction can boost the synergistic effect for advancing BST-based or other layered thermoelectrics.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2018YFA0702100and 2022YFB3803900)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences (CAS)’ Large-Scale Scientific Facility (Grant No. U1932106)the Sichuan University Innovation Research Program of China (Grant No. 2020SCUNL112)。
文摘AgCrSe2-based compounds have attracted much attention as an environmentally friendly thermoelectric material in recent years due to the intriguing liquid-like properties.However,the ultra-low carrier concentration and the high Ag_(Cr)deep-level defects limit the overall thermoelectric performance.Here,we successfully introduced Pb into Ag-deficient Ag_(0.97)CrSe_(2) alloys to tune the carrier concentration across a broad temperature range.The Pb^(2+) as an acceptor dopant preferentially occupies Cr sites,boosting the hole carrier concentration to 1.77×10^(19) cm^(-3) at room temperature.Furthermore,the Pb strongly inhibits the creation of intrinsic Ag_(Cr) defects,weakens the increased thermal excited ionization with the increasing temperature and slowed the rising trend of the carrier concentration.The designed carrier concentration matches the theoretically predicted optimized one over the entire temperature range,leading to a remarkable enhancement in power factor,especially the maximum power factor of ~500 μW·m^(-1)·K^(-2) at 750 K is superior to most previous results.Additionally,the abundant point defects promote phonon scattering,thus reducing the lattice thermal conductivity.As a result,the maximum figure of merit zT(~0.51 at 750 K) is achieved in Ag_(0.97)Cr_(0.995)Pb_(0.005)Se_(2).This work confirms the feasibility of manipulating deep-level defects to achieve temperature-dependent optimal carrier concentration and provides a valuable guidance for other thermoelectric materials.
基金supported by the National Natural Science Foundation of China(22109007 and 21825501)Beijing Institute of Technology Research Fund Program for Young Scholarsthe Tsinghua University Initiative Scientific Research Program。
文摘Single-atom catalysts serve as a promising candidate to realize noble-metal-free electrocatalytic oxygen reduction in acid media.However,their poor stability under working conditions strictly restrains their practical applications.Therefore,regeneration of their electrocatalytic activity is of great significance.Herein,the regeneration of a Fe-N-C single-atom catalyst is demonstrated to be feasible by a facile annealing regeneration strategy.The activity after regeneration recovers to that of the pristine electrocatalyst and surpasses the deactivated electrocatalyst.The regeneration mechanism is identified to be selfetching of the surface carbon layer and consequent exposure of the previously buried single-atom sites.Furthermore,the regeneration strategy is applicable to other single-atom catalysts.This work demonstrates the feasibility of regenerating oxygen reduction electrocatalysts and affords a pioneering approach to deal with rapid deactivation under working conditions.
基金This work was financially supported by the National Natural Science Foundation of China(No.11605116).
文摘Monoclinic SrAl_(2)Si_(2)O_(8) ceramics for Sr immobilization were prepared by a liquid-phase sintering method.The sintering temperature,mineral phase composition,microstructure,flexural strength,bulk density,and Sr ion leaching characteristics of the SrAl_(2)Si_(2)O_(8) ceramics were investigated.A crystalline monoclinic SrAl_(2)Si_(2)O_(8) phase formed through liquid-phase sintering at 1223 K.The introduction of four flux agents(B_(2)O_(3),CaO·2B_(2)O_(3),SrO·2B_(2)O_(3),and BaO·2B_(2)O_(3))to the SrAl_(2)Si_(2)O_(8) ceramics not only reduced the densification temperature and decreased the volatilization of Sr during high-temperature sintering but also impacted the mechanical properties of the ceramics.Product consistency tests showed that the leaching concentration of Sr ions in the sample with flux agent B_(2)O_(3) was the lowest,whereas that of Sr ions in the sample with flux agent BaO·2B_(2)O_(3) was the highest.These results show that the leaching concentration of Sr ions depends largely on the amorphous phase in the ceramics.Meanwhile,the formation of mineral analog ceramics containing Sr is an important factor to improve Sr immobilization.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0702100)the Joint Funds of the National Natural Science Foundation of China+1 种基金the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。
文摘The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).
基金supported by Beijing Natural Science Foundation(JQ20004)National Key Research and Development Program(2016YFA0202500)Scientific and Technological Key Project of Shanxi Province(20191102003).
文摘Oxygen reduction reaction(ORR)constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells.However,the kinetics of ORR is very sluggish and thus highperformance ORR electrocatalysts are highly regarded.Despite recent progress on minimizing the ORR halfwave potential as the current evaluation indicator,in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized.In this paper,a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation.Independent parameters regarding exchange current density,electron transfer number,and electrochemical active surface area can be respectively determined following the proposed method.This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.
文摘Introduction: This study is on a creek located 45°42′18″N,122°39′41″W called Sahnon Creek.And after we finished all the experi- ments and tests which helped us to get some data and samples from the creek,it's time for us to get the result of these samples and data.Here are two questions we have to solve and
基金supported by the Innovation Program of Shanghai Municipal Education Commission(2023ZKZD05)the National Natural Science Foundation of China(32172043,31971918 and 32170356)+2 种基金the Shanghai Science and Technology Innovation Action Plan Project(22N11900200)the Innovation Program of Chinese Academy of Agricultural Sciencesthe grant from the National Key Research and Development Program of China(2021YFA1300401).
文摘RNA-binding proteins(RBPs)are components of the post-transcriptional regulatory system,but their regulatory effects on complex traits remain unknown.Using an integrated strategy involving map-based cloning,functional characterizations,and transcriptomic and population genomic analyses,we revealed that RBP-K(LOC_Os08g23120),RBP-A(LOC_Os11g41890),and RBP-J(LOC_Os10g33230)encode proteins that form an RBP-A-J-K complex that negatively regulates rice yield-related traits.Examinations of the RBP-A-J-K complex indicated RBP-K functions as a relatively non-specific RBP chaperone that enables RBP-A and RBP-J to function normally.Additionally,RBP-J most likely affects GA pathways,resulting in considerable increases in grain and panicle lengths,but decreases in grain width and thickness.In contrast,RBP-A negatively regulates the expression of genes most likely involved in auxin-regulated pathways controlling cell wall elongation and carbohydrate transport,with substantial effects on the rice grain filling process as well as grain length and weight.Evolutionarily,RBP-K is relatively ancient and highly conserved,whereas RBP-J and RBP-A are more diverse.Thus,the RBP-A-J-K complex may represent a typical functional model for many RBPs and protein complexes that function at transcriptional and post-transcriptional levels in plants and animals for increased functional consistency,efficiency,and versatility,as well as increased evolutionary potential.Our results clearly demonstrate the importance of RBP-mediated post-transcriptional regulation for the diversity of complex traits.Furthermore,rice grain yield and quality may be enhanced by introducing various complete or partial loss-of-function mutations to specific RBP genes using clustered regularly interspaced palindromic repeats(CRISPR)/CRISPR-associated protein 9 technology and by exploiting desirable natural tri-genic allelic combinations at the loci encoding the components of the RBP-A-J-K complex through marker-assisted selection.
基金supported by a grant from the National High Technology Research and Development Program of China (2012AA10A303)
文摘Plant male reproductive development is a complex biological process, but the underlying mechanism is not well understood. Here, we characterized a rice （Oryza sativa L.） male sterile mutant. Based on map- based cloning and sequence analysis, we identified a 1,459-bp deletion in an adenosine triphosphate （ATP）-binding cassette （ABC） transporter gene, OsABCG15, causing abnormal anthers and male sterility. Therefore, we named this mutant osabcgl5. Expression analysis showed that OsABCG15 is expressed specifically in developmental anthers from stage 8 （meiosis II stage） to stage 10 （late microspore stage）. Two genes CYP704B2 and WDA1, involved in the biosynthesis of very-long-chain fatty acids for the establishment of the anther cuticle and pollen exine, were downregulated in osabcgl5 mutant, suggesting that OsABCG15 may play a key function in the processes related to sporopollenin biosynthesis or sporopollenin transfer from tapetal cells to anther Iocules. Consistently, histological analysis showed that osabcgl5 mutants developed obvious abnormality in postmeiotic tapetum degeneration, leading to rapid degredation of young microspores. The results suggest that OsABCG15 plays a critical role in exine formation and pollen development, similar to the homologous gene of AtABCG26 in Arabidopsis. This work is helpful to understand the regulatory network in rice anther development.
