Two-dimensional(2D)melting is a fundamental research topic in condensed matter physics,which can also provide guidance on fabricating new functional materials.Nevertheless,our understanding of 2D melting is still far ...Two-dimensional(2D)melting is a fundamental research topic in condensed matter physics,which can also provide guidance on fabricating new functional materials.Nevertheless,our understanding of 2D melting is still far from being complete due to existence of possible complicate transition mechanisms and absence of effective analysis methods.Here,using Monte Carlo simulations,we investigate 2D melting of 60°rhombs which melt from two different surface-fullycoverable crystals,a complex hexagonal crystal(cHX)whose primitive cell contains three rhombs,and a simple rhombic crystal(RB)whose primitive cell contains one rhomb.The melting of both crystals shows a sequence of solid,hexatic in molecular orientation(Hmo),and isotropic phases which obey the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young(BKTHNY)theory.However,local polymorphic configuration(LPC)based analysis reveals different melting mechanisms:the cHX-Hmotransition is driven by the proliferation of point-like defects during which defect-associated LPCs are generated sequentially,whereas the RB-Hmotransition is driven by line defects where defect-associated LPCs are generated simultaneously.These differences result in the observed different solid-Hmotransition points which areφA=0.812 for the cHX-HmoandφA=0.828 for the RB-Hmo.Our work will shed light on the initial-crystal-dependence of 2D melting behavior.展开更多
Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges.Transition metal dichalcogenide(TMD)-based ...Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges.Transition metal dichalcogenide(TMD)-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs'notable specific surface area,tunable elemental species and efficient utilization of single atoms.In order to enhance electrocatalytic performance,it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs.In this review,we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs.The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated,including substitution engineering,surface adsorption,vacancies,spatial confinement and dual-atom site strategies.For each modulation strategy,the effects of diverse local environments on various electrocatalytic applications are presented,such as the oxygen evolution reaction,oxygen reduction reaction,nitrogen reduction reaction,CO_(2)reduction reaction and CO oxidation.Ultimately,this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis.展开更多
A combined Ag nanoparticle with an insulating or conductive layer structure has been designed tor molecular detection using surface enhanced Raman scattering microscopy. Optical absorption studies revealed localized s...A combined Ag nanoparticle with an insulating or conductive layer structure has been designed tor molecular detection using surface enhanced Raman scattering microscopy. Optical absorption studies revealed localized surface plasmon resonance, which shows regular red shift with increasing environmental dielectric constant. With the combined structure of surface enhanced Raman scattering substrates and rhodamine 6C as a test molecule, the results in this paper show that the absorption has a linear relationship with the local electromagnetic field for insulating substrates, and the electrical property of the substrate has a non-negligible effect on the intensity of the local electromagnetic field and hence the Raman enhancement.展开更多
The structure and function of protein are strongly pH-dependence. However, the inonization state of the protein varied with the pH value also depends on the local structure
By collecting the environmental target constraints in the annual government work report of prefecture-level cities,this paper studies its impact on local enterprises’OFDI.The main conclusions are as follows:(1)Both d...By collecting the environmental target constraints in the annual government work report of prefecture-level cities,this paper studies its impact on local enterprises’OFDI.The main conclusions are as follows:(1)Both direct and indirect constraints have a significant positive impact on enterprises’OFDI,and the degree of direct constraints is stronger than that of indirect constraints.(2)Environmental target constraints of local governments will affect corporate OFDI behavior by affecting production costs,local economic development level and local openness,and(3)There are regional heterogeneity and investment type heterogeneity in the impact of environmental goal constraints on corporate OFDI.The suggestions are as follows:government departments can appropriately strengthen the constraint intensity of environmental targets and formulate specific restraint rules for industries with different levels of pollution,so as to effectively make use of the technology spillover effects brought about by OFDI to promote the upgrading of domestic industrial structure.When making OFDI,enterprises should clarify the investment motivation,strengthen corporate social responsibility,and make use of technology spillover effect to promote the upgrading and development of home country industry while being beneficial to their own development.展开更多
In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services....In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services.Despite their ecological significance,these ecosystems remain poorly studied.Particularly soil mesofauna,which play critical roles in nutrient cycling and organic matter dynamics,remain to be explored.We investigated the composition,abundance,and richness of taxa and feeding guilds of soil mesofauna communities across 10 vegas.These wetlands were distributed along an environmental gradient,in an elevation range of 3323-4748 m a.s.l.,where we analysed soil properties and plant communities.We collected a total of 5239 invertebrates,from which Acari was the most abundant group,followed by Collembola.Regarding feeding guilds,detritivores and predators dominated soil mesofauna communities.Variability in taxa abundance and richness was strongly influenced by local soil properties,such as organic matter,carbon-to-nitrogen ratio,and phosphorus content,as well as plant community attributes,particularly cushion plant cover.However,no soil or vegetation variables explained the differences in taxa identity across vegas.These findings highlight the critical role of local heterogeneity in shaping soil mesofauna communities and provide the first insights into these understudied ecosystems.展开更多
Single-atom catalysts(SACs)with M-N_(4)structure have drawn significant attention due to the facile preparation,maximum atom efficiency,unique electronic properties,uniform active sites,and excellent activity.Such cat...Single-atom catalysts(SACs)with M-N_(4)structure have drawn significant attention due to the facile preparation,maximum atom efficiency,unique electronic properties,uniform active sites,and excellent activity.Such catalysts integrated the merits of traditional homogeneous and heterogeneous catalysts effectively solve the cost,activity,and reuse problems.More importantly,the M-N_(4)structure is flexible and other species like atoms,groups,and particles can be added to precisely control the local environment of M-N_(4)to further improve the catalytic performance.Although unprecedented progress has been made,it remains difficulties in the rational design and controllable synthesis of a suitable SAC for a certain application.This review introduces the progress of M-N_(4)catalysts and summarizes the strategies to modulate the M-N_(4)structure,including changing the coordination number,tailoring the coordination structure,coordinating with groups,creating dual-atom catalysts(DACs),and coexisting of SAC with DAC and cluster.Special emphasis is placed on the preparation,structure characterization,and reaction mechanism of M-N_(4)-derived catalysts.Finally,the current challenges of these catalysts are also discussed to provide guidelines for the future design of efficient catalysts.展开更多
ZnO films containing Er and Ge nanocrystals(nc-Ge) were synthesized and their photoluminescence(PL) properties were studied. Visible and near-infrared PL intensities are found to be greatly increased in nc-Ge-containi...ZnO films containing Er and Ge nanocrystals(nc-Ge) were synthesized and their photoluminescence(PL) properties were studied. Visible and near-infrared PL intensities are found to be greatly increased in nc-Ge-containing film. Er-related 1.54 μm emission has been investigated under several excitation conditions upon different kinds of Ge, Er codoped ZnO thin films. 1.54 μm PL enhancement accompanied by the appearance of nc-Ge implies a significant correlation between nc-Ge and PL emission of Er^(3+). The increased intensity of 1.54 μm in Ge:Er:ZnO film is considered to come from the joint effect of the local potential distortion around Er^(3+)and the possibleenergy transfer from nc-Ge to Er^(3+).展开更多
Essentially clearing the structure-activity relationship between iron carbide catalysts involving multiple active centers to understand the reaction mechanism of CO hydrogenation conversion process is still a great ch...Essentially clearing the structure-activity relationship between iron carbide catalysts involving multiple active centers to understand the reaction mechanism of CO hydrogenation conversion process is still a great challenge.Here,two main micro-environment factors,namely electronic properties and geometrical effects were found to have an integrated effect on the mechanism of CO hydrogenation conversion,involving active sites on multiple crystal phases.The Bader charge of the surface Fe atoms on the active sites had a guiding effect on the CO activation pathway,while the spatial configuration of the active sites greatly affected the energy barriers of CO activation.Although the defective surfaces were more conducive to CO activation,the defective sites were not the only sites to dissociate CO,as CO always tended to dissociate in a wider area.This synergistic effect of the micro-environment also occurred during the CO conversion process.Surface C atoms on relatively flat configurations were more likely to form methane,while the electronic properties of the active sites could effectively describe the C-C coupling process,as well as distinguish the coupling mechanisms.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has been developed as a promising and attractive strategy to close the anthropogenic carbon cycle.Among various reduction products,multi-carbon(C_(2+))oxygenate and h...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has been developed as a promising and attractive strategy to close the anthropogenic carbon cycle.Among various reduction products,multi-carbon(C_(2+))oxygenate and hydrocarbon compounds are desirable value-added fuels or chemicals.Extensive researches have revealed the crucial role of local CO_(2)and H_(2)O concentrations(or the adsorption of ^(*)CO and ^(*)H)close to the electrode/catalyst surface in manipulating multi-carbon generation pathways.In this mini reviews,we mainly summarized the recent progress of this field over the past five years.The modulating strategies for the hydrogen and carbon species ratio can be divided into three categories,i.e.,catalyst morphology,electrolyte composition and mass transfer.The effectiveness of the aforementioned strategies in promoting multi-carbon product selectivity was discussed in detail from the perspectives of tuning the local CO_(2)and H_(2)O concentrations and the subsequent thermodynamic-and kinetic-controlled ^(*)CO and ^(*)H ratios.Finally,the critical challenges remaining in balancing the ratio of CO_(2)and H_(2)O as well as potential upgrading directions for future research are addressed.展开更多
The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transitio...The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transition caused by the large size difference between Na+and tetrahedral gaps lead to poor rate and cycling performance.Therefore,a scalable and feasible strategy was proposed to modulate local chemical environment by introducing Mg^(2+)and B^(3+)into O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn0.4O_(2),which can distinctly improve kinetic transport rate as well as electrochemical performance.The capacity retention of O_(3)-(Na_(0.82)Mg_(0.04))(Ni_(0.2)Fe_(0.4)Mn_(0.4))B_(0.02)O_(2)(NFMB)increases from 43.3%and 12.4%to 89.5%and 89.0%at 1 C and 3 C after 200 cycles,respectively.Moreover,the electrode still delivers high rate capacity of 93.9 mAh/g when current density increases to 10 C.Mg^(2+)ions riveted on Na layer act as a“pillar”to stabilize crystal structure and inhibit structural change during the desodiumization process.B^(3+)ions entering tetrahedral interstice of the TM layer strengthen the TM-O bond,lower Na+diffusion energy barrier and inhibits the slip of TM layer.Furthermore,the assembled full batteries with the modified cathode material deliver a high energy density of 278.2Wh/kg with commercial hard carbon as anode.This work provides a strategy for the modification of high-performance SIB layered oxide materials to develop the next-generation cost-effective energy storage grid systems.展开更多
When considering emissions control problems associated with carbon dioxide (CO2), social planning over quite a long-term horizon is usually considered to be necessary because it takes much time for the full absorption...When considering emissions control problems associated with carbon dioxide (CO2), social planning over quite a long-term horizon is usually considered to be necessary because it takes much time for the full absorption of CO2 by oceans and forests. Sometimes the required time horizon even becomes infinite. Such a fact seems to impose patience beyond the limits of human cognition. However, this study proves that the first-best emissions scenario can be achieved only by local altruism, which is dubbed parentage. Parentage is defined as the action of applying zero social discount rate to its subsequent generation, and discounting the utility of generations thereafter infinitely. In this sense, the nearly first-best emissions scenario is feasible within the ordinal cognition and benevolence of human beings. This paper also examines the definition of egalitarian sustainability, in which the utility of every generation must be kept constant, and reveals that such a definition of sustainability possibly provokes the inefficient intergenerational allocation of CO2. This is because the vested interest of the predecessors is put much importance in the process of the planning. It is required more rigid sustainability concept, in which the utility of each generation is no less decreasing through time and at least strictly increasing locally, to achieve the efficient allocation of CO2. One will find that the intergenerational allocation by the local altruism satisfies this property.展开更多
This paper presents a probabilistic algorithm to collaborate distributed sensors for mobile robot localization. It uses a sample-based version of Markov localization—Monte Carlo localization (MCL), capable of localiz...This paper presents a probabilistic algorithm to collaborate distributed sensors for mobile robot localization. It uses a sample-based version of Markov localization—Monte Carlo localization (MCL), capable of localizing mobile robot in an any-time fashion. During robot localization given a known environment model, MCL method is employed to update robot’s belief whichever information (positive or negative) attained from environmental sensors. Meanwhile, an implementation is presented that uses color environmental cameras for robot detection. All the parameters of each environmental camera are unknown in advance and need be calibrated independently by robot. Once calibrated, the positive and negative detection models can be built up according to the parameters of environmental cameras. A further experiment, obtained with the real robot in an indoor office environment, illustrates it has drastic improvement in global localization speed and accuracy using our algorithm.展开更多
China's poor energy development and in-situ conversion legislation, environment laws and energy laws lead to a severe environmental issue in energy source. This paper uses comparison and logical methods to discuss...China's poor energy development and in-situ conversion legislation, environment laws and energy laws lead to a severe environmental issue in energy source. This paper uses comparison and logical methods to discuss Chapter 4 of Energy Law (Draft for Soliciting Opinions). Energy development is taken as a separate chapter; in-situ energy conversion is added to energy processing and conversion, common features are summarized to form general provisions and other provisions. According to respective characteristics of system for total amount control of energy development, performance guarantee system, environmental trust fund system, energy retaining system and environmental lien system, incorporate them into energy development, in-situ energy conversion and energy processing and conversion, in the hope of solving China's shortage of supply for environmental protection laws on energy development and in-situ conversion, responding to times of environmental protection, and optimizing China's Energy Law.展开更多
Tobacco use continues to be the leading preventable cause of premature death in the United States, killing over 430,000 people annually. To-bacco initiation and use among youth remains a significant public health conc...Tobacco use continues to be the leading preventable cause of premature death in the United States, killing over 430,000 people annually. To-bacco initiation and use among youth remains a significant public health concern. Despite declines in U.S. youth tobacco use in recent years, state and national survey results are still cause for alarm. Although traditional school-based curricular programs are the most common strategy to prevent or reduce youth tobacco use, their effectiveness may be limited because young people are immersed in a broader social context in which tobacco is readily available. Environmental strategies change this social context by focusing on policy, enforcement, and media. A compelling body of evidence suggests that interventions at the state and federal levels can, when implemented in combination, reduce youth tobacco use. The impact of policies implemented at the local levels is less well understood and effects of environmental strategies on smokeless tobacco consumption have been largely ignored. The purpose of this paper is to review the literature on environmental strategies implemented at the local level on youth use of both cigarettes and smokeless tobacco. We highlight results of the extant *-literature, hypothesize possible effects where research is lacking, and suggest where future studies might be warranted.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874277,21621004,12104453,and 12090054)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33030300)
文摘Two-dimensional(2D)melting is a fundamental research topic in condensed matter physics,which can also provide guidance on fabricating new functional materials.Nevertheless,our understanding of 2D melting is still far from being complete due to existence of possible complicate transition mechanisms and absence of effective analysis methods.Here,using Monte Carlo simulations,we investigate 2D melting of 60°rhombs which melt from two different surface-fullycoverable crystals,a complex hexagonal crystal(cHX)whose primitive cell contains three rhombs,and a simple rhombic crystal(RB)whose primitive cell contains one rhomb.The melting of both crystals shows a sequence of solid,hexatic in molecular orientation(Hmo),and isotropic phases which obey the Berezinskii-Kosterlitz-Thouless-Halperin-Nelson-Young(BKTHNY)theory.However,local polymorphic configuration(LPC)based analysis reveals different melting mechanisms:the cHX-Hmotransition is driven by the proliferation of point-like defects during which defect-associated LPCs are generated sequentially,whereas the RB-Hmotransition is driven by line defects where defect-associated LPCs are generated simultaneously.These differences result in the observed different solid-Hmotransition points which areφA=0.812 for the cHX-HmoandφA=0.828 for the RB-Hmo.Our work will shed light on the initial-crystal-dependence of 2D melting behavior.
基金supported by the“Teli Young Scholar”ProgramTechnology Innovation Program of Beijing Institute of Technology+2 种基金“Xiaomi Scholar”Program“Langyue”ProgramBeijing Municipal Natural Science Foundation(No.2232023)。
文摘Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges.Transition metal dichalcogenide(TMD)-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs'notable specific surface area,tunable elemental species and efficient utilization of single atoms.In order to enhance electrocatalytic performance,it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs.In this review,we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs.The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated,including substitution engineering,surface adsorption,vacancies,spatial confinement and dual-atom site strategies.For each modulation strategy,the effects of diverse local environments on various electrocatalytic applications are presented,such as the oxygen evolution reaction,oxygen reduction reaction,nitrogen reduction reaction,CO_(2)reduction reaction and CO oxidation.Ultimately,this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis.
基金Project supported by Hi-Tech Research and Development Program of China(Grant Nos.2007AA05Z436 and 2009AA050602)Science and Technology Foundation of Tianjin(Grant No.08ZCKFGX03500)+3 种基金National Basic Research Program of China(Grant Nos.2006CB202602 and 2006CB202603)National Natural Science Foundation of China(Grant No.60976051)International Cooperation Project between China-Greece Government(Grant Nos.2006DFA62390 and 2009DFA62580)Program for New Century Excellent Talents in University of China(Grant No.NCET-08-0295)
文摘A combined Ag nanoparticle with an insulating or conductive layer structure has been designed tor molecular detection using surface enhanced Raman scattering microscopy. Optical absorption studies revealed localized surface plasmon resonance, which shows regular red shift with increasing environmental dielectric constant. With the combined structure of surface enhanced Raman scattering substrates and rhodamine 6C as a test molecule, the results in this paper show that the absorption has a linear relationship with the local electromagnetic field for insulating substrates, and the electrical property of the substrate has a non-negligible effect on the intensity of the local electromagnetic field and hence the Raman enhancement.
文摘The structure and function of protein are strongly pH-dependence. However, the inonization state of the protein varied with the pH value also depends on the local structure
文摘By collecting the environmental target constraints in the annual government work report of prefecture-level cities,this paper studies its impact on local enterprises’OFDI.The main conclusions are as follows:(1)Both direct and indirect constraints have a significant positive impact on enterprises’OFDI,and the degree of direct constraints is stronger than that of indirect constraints.(2)Environmental target constraints of local governments will affect corporate OFDI behavior by affecting production costs,local economic development level and local openness,and(3)There are regional heterogeneity and investment type heterogeneity in the impact of environmental goal constraints on corporate OFDI.The suggestions are as follows:government departments can appropriately strengthen the constraint intensity of environmental targets and formulate specific restraint rules for industries with different levels of pollution,so as to effectively make use of the technology spillover effects brought about by OFDI to promote the upgrading of domestic industrial structure.When making OFDI,enterprises should clarify the investment motivation,strengthen corporate social responsibility,and make use of technology spillover effect to promote the upgrading and development of home country industry while being beneficial to their own development.
基金supported by FONCYT grants(PICT 2016-2173,PICT 2018-04228).
文摘In the Argentine Puna,a particular type of wetlands called vegas are considered unique,as they are the main biodiversity hotspots in this arid high-elevation environment.Also,they provide essential ecosystem services.Despite their ecological significance,these ecosystems remain poorly studied.Particularly soil mesofauna,which play critical roles in nutrient cycling and organic matter dynamics,remain to be explored.We investigated the composition,abundance,and richness of taxa and feeding guilds of soil mesofauna communities across 10 vegas.These wetlands were distributed along an environmental gradient,in an elevation range of 3323-4748 m a.s.l.,where we analysed soil properties and plant communities.We collected a total of 5239 invertebrates,from which Acari was the most abundant group,followed by Collembola.Regarding feeding guilds,detritivores and predators dominated soil mesofauna communities.Variability in taxa abundance and richness was strongly influenced by local soil properties,such as organic matter,carbon-to-nitrogen ratio,and phosphorus content,as well as plant community attributes,particularly cushion plant cover.However,no soil or vegetation variables explained the differences in taxa identity across vegas.These findings highlight the critical role of local heterogeneity in shaping soil mesofauna communities and provide the first insights into these understudied ecosystems.
基金This work was supported by the National Natural Science Foundation of China(Nos.22002191,12105287,22179125,22002147,and 12025505)the Natural Science Foundation of Guangdong Province(Nos.2022A1515010928 and 2022A1515012661)+3 种基金Shenzhen Science and Technology Program(No.JCYJ20220530150200002)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110956)the Youth Innovation Promotion Association CAS(No.2022458)Fundamental Research Funds for the Central Universities(No.KY2310000020).
文摘Single-atom catalysts(SACs)with M-N_(4)structure have drawn significant attention due to the facile preparation,maximum atom efficiency,unique electronic properties,uniform active sites,and excellent activity.Such catalysts integrated the merits of traditional homogeneous and heterogeneous catalysts effectively solve the cost,activity,and reuse problems.More importantly,the M-N_(4)structure is flexible and other species like atoms,groups,and particles can be added to precisely control the local environment of M-N_(4)to further improve the catalytic performance.Although unprecedented progress has been made,it remains difficulties in the rational design and controllable synthesis of a suitable SAC for a certain application.This review introduces the progress of M-N_(4)catalysts and summarizes the strategies to modulate the M-N_(4)structure,including changing the coordination number,tailoring the coordination structure,coordinating with groups,creating dual-atom catalysts(DACs),and coexisting of SAC with DAC and cluster.Special emphasis is placed on the preparation,structure characterization,and reaction mechanism of M-N_(4)-derived catalysts.Finally,the current challenges of these catalysts are also discussed to provide guidelines for the future design of efficient catalysts.
基金National Natural Science Foundation of China(NSFC)(11475105)
文摘ZnO films containing Er and Ge nanocrystals(nc-Ge) were synthesized and their photoluminescence(PL) properties were studied. Visible and near-infrared PL intensities are found to be greatly increased in nc-Ge-containing film. Er-related 1.54 μm emission has been investigated under several excitation conditions upon different kinds of Ge, Er codoped ZnO thin films. 1.54 μm PL enhancement accompanied by the appearance of nc-Ge implies a significant correlation between nc-Ge and PL emission of Er^(3+). The increased intensity of 1.54 μm in Ge:Er:ZnO film is considered to come from the joint effect of the local potential distortion around Er^(3+)and the possibleenergy transfer from nc-Ge to Er^(3+).
基金supported by the Research Fund for National Key Research and Development Program of China(2022YFA1503804,2021YFA1501403)the Natural Science Foundation of China(22208094,21922803,92034301,22008066 and 21776077)+2 种基金the China Postdoctoral Science Foundation(BX20190116)the Innovation Program of Shanghai Municipal Education Commission(17ZR1407300)the Program of Shanghai Academic/Technology Research Leader(21XD1421000).
文摘Essentially clearing the structure-activity relationship between iron carbide catalysts involving multiple active centers to understand the reaction mechanism of CO hydrogenation conversion process is still a great challenge.Here,two main micro-environment factors,namely electronic properties and geometrical effects were found to have an integrated effect on the mechanism of CO hydrogenation conversion,involving active sites on multiple crystal phases.The Bader charge of the surface Fe atoms on the active sites had a guiding effect on the CO activation pathway,while the spatial configuration of the active sites greatly affected the energy barriers of CO activation.Although the defective surfaces were more conducive to CO activation,the defective sites were not the only sites to dissociate CO,as CO always tended to dissociate in a wider area.This synergistic effect of the micro-environment also occurred during the CO conversion process.Surface C atoms on relatively flat configurations were more likely to form methane,while the electronic properties of the active sites could effectively describe the C-C coupling process,as well as distinguish the coupling mechanisms.
基金supported by the National Natural Science Foundation of China(No.52309132)Shandong Provincial Natural Science Foundation(No.ZR2023ME014).
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)has been developed as a promising and attractive strategy to close the anthropogenic carbon cycle.Among various reduction products,multi-carbon(C_(2+))oxygenate and hydrocarbon compounds are desirable value-added fuels or chemicals.Extensive researches have revealed the crucial role of local CO_(2)and H_(2)O concentrations(or the adsorption of ^(*)CO and ^(*)H)close to the electrode/catalyst surface in manipulating multi-carbon generation pathways.In this mini reviews,we mainly summarized the recent progress of this field over the past five years.The modulating strategies for the hydrogen and carbon species ratio can be divided into three categories,i.e.,catalyst morphology,electrolyte composition and mass transfer.The effectiveness of the aforementioned strategies in promoting multi-carbon product selectivity was discussed in detail from the perspectives of tuning the local CO_(2)and H_(2)O concentrations and the subsequent thermodynamic-and kinetic-controlled ^(*)CO and ^(*)H ratios.Finally,the critical challenges remaining in balancing the ratio of CO_(2)and H_(2)O as well as potential upgrading directions for future research are addressed.
基金supported by National Natural Science Foundation(Nos.52364035,52364036 and U23A20577)Guangxi Natural Science Foundation(Nos.2022GXNSFAA035610 and 2022GXNSFAA035471)Guangxi Science and Technology Base and Talent Project(No.GUIKE AD23026038).
文摘The O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn_(0.4)O_(2)layered oxide cathode material possesses the advantages of high specific capacity,low cost,and simple synthesis.However,sluggish kinetics and complicated phase transition caused by the large size difference between Na+and tetrahedral gaps lead to poor rate and cycling performance.Therefore,a scalable and feasible strategy was proposed to modulate local chemical environment by introducing Mg^(2+)and B^(3+)into O_(3)-Na_(0.85)Ni_(0.2)Fe_(0.4)Mn0.4O_(2),which can distinctly improve kinetic transport rate as well as electrochemical performance.The capacity retention of O_(3)-(Na_(0.82)Mg_(0.04))(Ni_(0.2)Fe_(0.4)Mn_(0.4))B_(0.02)O_(2)(NFMB)increases from 43.3%and 12.4%to 89.5%and 89.0%at 1 C and 3 C after 200 cycles,respectively.Moreover,the electrode still delivers high rate capacity of 93.9 mAh/g when current density increases to 10 C.Mg^(2+)ions riveted on Na layer act as a“pillar”to stabilize crystal structure and inhibit structural change during the desodiumization process.B^(3+)ions entering tetrahedral interstice of the TM layer strengthen the TM-O bond,lower Na+diffusion energy barrier and inhibits the slip of TM layer.Furthermore,the assembled full batteries with the modified cathode material deliver a high energy density of 278.2Wh/kg with commercial hard carbon as anode.This work provides a strategy for the modification of high-performance SIB layered oxide materials to develop the next-generation cost-effective energy storage grid systems.
文摘When considering emissions control problems associated with carbon dioxide (CO2), social planning over quite a long-term horizon is usually considered to be necessary because it takes much time for the full absorption of CO2 by oceans and forests. Sometimes the required time horizon even becomes infinite. Such a fact seems to impose patience beyond the limits of human cognition. However, this study proves that the first-best emissions scenario can be achieved only by local altruism, which is dubbed parentage. Parentage is defined as the action of applying zero social discount rate to its subsequent generation, and discounting the utility of generations thereafter infinitely. In this sense, the nearly first-best emissions scenario is feasible within the ordinal cognition and benevolence of human beings. This paper also examines the definition of egalitarian sustainability, in which the utility of every generation must be kept constant, and reveals that such a definition of sustainability possibly provokes the inefficient intergenerational allocation of CO2. This is because the vested interest of the predecessors is put much importance in the process of the planning. It is required more rigid sustainability concept, in which the utility of each generation is no less decreasing through time and at least strictly increasing locally, to achieve the efficient allocation of CO2. One will find that the intergenerational allocation by the local altruism satisfies this property.
文摘This paper presents a probabilistic algorithm to collaborate distributed sensors for mobile robot localization. It uses a sample-based version of Markov localization—Monte Carlo localization (MCL), capable of localizing mobile robot in an any-time fashion. During robot localization given a known environment model, MCL method is employed to update robot’s belief whichever information (positive or negative) attained from environmental sensors. Meanwhile, an implementation is presented that uses color environmental cameras for robot detection. All the parameters of each environmental camera are unknown in advance and need be calibrated independently by robot. Once calibrated, the positive and negative detection models can be built up according to the parameters of environmental cameras. A further experiment, obtained with the real robot in an indoor office environment, illustrates it has drastic improvement in global localization speed and accuracy using our algorithm.
基金Supported by Key Project of Sichuan Education Department(Grant No.:11SB098)Key Project of Humanities and Social Sciences of Sichuan University of Arts and Science (Grant No.:2010A04R)
文摘China's poor energy development and in-situ conversion legislation, environment laws and energy laws lead to a severe environmental issue in energy source. This paper uses comparison and logical methods to discuss Chapter 4 of Energy Law (Draft for Soliciting Opinions). Energy development is taken as a separate chapter; in-situ energy conversion is added to energy processing and conversion, common features are summarized to form general provisions and other provisions. According to respective characteristics of system for total amount control of energy development, performance guarantee system, environmental trust fund system, energy retaining system and environmental lien system, incorporate them into energy development, in-situ energy conversion and energy processing and conversion, in the hope of solving China's shortage of supply for environmental protection laws on energy development and in-situ conversion, responding to times of environmental protection, and optimizing China's Energy Law.
文摘Tobacco use continues to be the leading preventable cause of premature death in the United States, killing over 430,000 people annually. To-bacco initiation and use among youth remains a significant public health concern. Despite declines in U.S. youth tobacco use in recent years, state and national survey results are still cause for alarm. Although traditional school-based curricular programs are the most common strategy to prevent or reduce youth tobacco use, their effectiveness may be limited because young people are immersed in a broader social context in which tobacco is readily available. Environmental strategies change this social context by focusing on policy, enforcement, and media. A compelling body of evidence suggests that interventions at the state and federal levels can, when implemented in combination, reduce youth tobacco use. The impact of policies implemented at the local levels is less well understood and effects of environmental strategies on smokeless tobacco consumption have been largely ignored. The purpose of this paper is to review the literature on environmental strategies implemented at the local level on youth use of both cigarettes and smokeless tobacco. We highlight results of the extant *-literature, hypothesize possible effects where research is lacking, and suggest where future studies might be warranted.
