Constructing a cross-border power energy system with multiagent power energy as an alliance is important for studying cross-border power-trading markets.This study considers multiple neighboring countries in the form ...Constructing a cross-border power energy system with multiagent power energy as an alliance is important for studying cross-border power-trading markets.This study considers multiple neighboring countries in the form of alliances,introduces neighboring countries’exchange rates into the cross-border multi-agent power-trading market and proposes a method to study each agent’s dynamic decision-making behavior based on evolutionary game theory.To this end,this study uses three national agents as examples,constructs a tripartite evolutionary game model,and analyzes the evolution process of the decision-making behavior of each agent member state under the initial willingness value,cost of payment,and additional revenue of the alliance.This research helps realize cross-border energy operations so that the transaction agent can achieve greater trade profits and provides a theoretical basis for cooperation and stability between multiple agents.展开更多
Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon emissions.The method of calcul...Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon emissions.The method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power grid.Therefore,it cannot provide carbon factor information beforehand.To address this issue,a prediction model based on the graph attention network is proposed.The model uses a graph structure that is suitable for the topology of the power grid and designs a supervised network using the loads of the grid nodes and the corresponding carbon factor data.The network extracts features and transmits information more suitable for the power system and can flexibly adjust the equivalent topology,thereby increasing the diversity of the structure.Its input and output data are simple,without the power grid parameters.We demonstrated its effect by testing IEEE-39 bus and IEEE-118 bus systems with average error rates of 2.46%and 2.51%.展开更多
Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendri...Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendrites and infinite volume change during repeated plating/stripping cycles hinder its practical applications immensely. Herein, a house-like Li anode (housed Li) was designed to circumvent the above issues. The house matrix was composed of carbon fiber matrix and affords a stable structure to relieve the volume change. An artificial solid electrolyte layer was formed on composite Li metal, just like the roof of a house, which facilitates uniform Li ions diffusion and serves as a physical barrier against electrolyte corrosion. With the combination of solid electrolyte layer and matrix in the composite Li metal anode, both dendrite growth and volume expansion are remarkably inhibited. The housed Li|LiFePO4 batteries exhibited over 95% capacity retention after 500 cycles at 1.0 C in coin cell and 85% capacity retention after 80 cycles at 0.5 C in pouch cell. The rationally combination of solid electrolyte layer protection and housed framework in one Li metal anode sheds fresh insights on the design principle of a safe and long-lifespan Li metal anode for Li metal batteries.展开更多
Lithium(Li) metal anode has received extensive attentions due to its ultrahigh theoretical capacity and the most negative electrode potential. However, dendrite growth severely impedes the practical applications of th...Lithium(Li) metal anode has received extensive attentions due to its ultrahigh theoretical capacity and the most negative electrode potential. However, dendrite growth severely impedes the practical applications of the Li metal anode in rechargeable batteries. In this contribution, a mesoporous graphene with a high specific surface area was synthesized to host the Li metal anode. The mesoporous graphene host(MGH) has a high specific surface area(2090 m^2/g), which affords free space and an interconnected conductive pathway for Li plating and stripping, thus alleviating the volume variation and reducing the generation of dead Li during repeated cycles. More importantly, the high specific surface area of MGH efficiently reduces the local current density of the electrode, which favors a uniform Li nucleation and plating behavior, rendering a dendritefree deposition morphology at a low overpotential. These factors synergistically boost the Li utilization(90.1% vs. 70.1% for Cu foil) and life span(150 cycles vs. 100 cycles for Cu foil) with a low polarization of MGH electrode at an ultrahigh current of 15.0 mA/cm^2. The as-prepared MGH can provide fresh insights into the electrode design of the Li metal anode operating at high rates.展开更多
The biodiversity of the mycobiome,an important component of the oral microbial community,and the roles of fungal–bacterial and fungal–immune system interactions in the pathogenesis of oral lichen planus (OLP) remain...The biodiversity of the mycobiome,an important component of the oral microbial community,and the roles of fungal–bacterial and fungal–immune system interactions in the pathogenesis of oral lichen planus (OLP) remain largely uncharacterized.In this study,we sequenced the salivary mycobiome and bacteriome associated with OLP.First,we described the dysbiosis of the microbiome in OLP patients,which exhibits lower levels of fungi and higher levels of bacteria.Significantly higher abundances of the fungi Candida and Aspergillus in patients with reticular OLP and of Alternaria and Sclerotiniaceae_unidentified in patients with erosive OLP were observed compared to the healthy controls.Aspergillus was identified as an “OLP-associated” fungus because of its detection at a higher frequency than in the healthy controls.Second,the co-occurrence patterns of the salivary mycobiome–bacteriome demonstrated negative associations between specific fungal and bacterial taxa identified in the healthy controls,which diminished in the reticular OLP group and even became positive in the erosive OLP group.Moreover,the oral cavities of OLP patients were colonized by dysbiotic oral flora with lower ecological network complexity and decreased fungal–Firmicutes and increased fungal–Bacteroidetes sub-networks.Third,several keystone fungal genera (Bovista,Erysiphe,Psathyrella,etc.) demonstrated significant correlations with clinical scores and IL-17 levels.Thus,we established that fungal dysbiosis is associated with the aggravation of OLP.Fungal dysbiosis could alter the salivary bacteriome or may reflect a direct effect of host immunity,which participates in OLP pathogenesis.展开更多
Lithium(Li)metal anodes promise an ultrahigh theoretical energy density and low redox potential,thus being the critical energy material for next-generation batteries.Unfortunately,the formation of Li dendrites in Li m...Lithium(Li)metal anodes promise an ultrahigh theoretical energy density and low redox potential,thus being the critical energy material for next-generation batteries.Unfortunately,the formation of Li dendrites in Li metal anodes remarkably hinders the practical applications of Li metal anodes.Herein,the dynamic evolution of discrete Li dendrites and aggregated Li dendrites with increasing current densities is visualized by in-situ optical microscopy in conjunction with ex-situ scanning electron microscopy.As revealed by the phase field simulations,the formation of aggregated Li dendrites under high current density is attributed to the locally concentrated electric field rather than the depletion of Li ions.More specifically,the locally concentrated electric field stems from the spatial inhomogeneity on the Li metal surface and will be further enhanced with increasing current densities.Adjusting the above two factors with the help of the constructed phase field model is able to regulate the electrodeposited morphology from aggregated Li dendrites to discrete Li dendrites,and ultimately columnar Li morphology.The methodology and mechanistic understanding established herein give a significant step toward the practical applications of Li metal anodes.展开更多
Lithium metal batteries are the most promising choices for next-generation high-energy–density batteries. However, there is little mechanism understanding on lithium dendrite growth during lithium plating and the dea...Lithium metal batteries are the most promising choices for next-generation high-energy–density batteries. However, there is little mechanism understanding on lithium dendrite growth during lithium plating and the dead lithium(the main component of inactive lithium) formation during lithium stripping. This work proposed a phase field model to describe the lithium stripping process with dead lithium formation.The coupling of galvanostatic conditions enables the phase field method to accurately match experimental results. The factors influencing the dead lithium formation on the increasing discharge polarization are revealed. Besides, the simulation of the battery polarization curve, the capacity loss peak, and the Coulomb efficiency is realized. This contribution affords an insightful understanding on dead lithium formation with phase field methods, which can contribute general principles on rational design of lithium metal batteries.展开更多
Light detection and ranging(LiDAR)has contributed immensely to forest mapping and 3D tree modelling.From the perspective of data acquisition,the integration of LiDAR data from different platforms would enrich forest i...Light detection and ranging(LiDAR)has contributed immensely to forest mapping and 3D tree modelling.From the perspective of data acquisition,the integration of LiDAR data from different platforms would enrich forest information at the tree and plot levels.This research develops a general framework to integrate ground-based and UAV-LiDAR(ULS)data to better estimate tree parameters based on quantitative structure modelling(QSM).This is accomplished in three sequential steps.First,the ground-based/ULS LiDAR data were co-registered based on the local density peaks of the clustered canopy.Next,redundancy and noise were removed for the ground-based/ULS LiDAR data fusion.Finally,tree modeling and biophysical parameter retrieval were based on QSM.Experiments were performed for Backpack/Handheld/UAV-based multi-platform mobile LiDAR data of a subtropical forest,including poplar and dawn redwood species.Generally,ground-based/ULS LiDAR data fusion outperforms ground-based LiDAR with respect to tree parameter estimation compared to field data.The fusion-derived tree height,tree volume,and crown volume significantly improved by up to 9.01%,5.28%,and 18.61%,respectively,in terms of rRMSE.By contrast,the diameter at breast height(DBH)is the parameter that has the least benefits from fusion,and rRMSE remains approximately the same,because stems are already well sampled from ground data.Additionally,particularly for dense forests,the fusion-derived tree parameters were improved compared to those derived from ground-based LiDAR.Ground-based LiDAR can potentially be used to estimate tree parameters in low-stand-density forests,whereby the improvement owing to fusion is not significant.展开更多
Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of prac...Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of practical lithium metal batteries.Methods of driving lithium metal to deposit inside the pores of structured lithium metal anodes have always been one of the most concerned issues,especially for highly conductive frameworks.An electrochemical phase field theory with galvanostatic lithium plating process is employed in this work,the mechanism that illustrates the preference of lithium metal to deposit at the top of the framework structure has been revealed,and through the simulation analysis of various regulating strategies,the strategies that can efficiently drive lithium to deposit inside structured pores are summarized.This work presents the theoretical calculation and analysis methods that can be used for the rational design of lithium metal batteries.展开更多
Solid-state batteries have received increasing attention in scientific and industrial communities,which benefits from the intrinsically safe solid electrolytes(SEs).Although much effort has been devoted to designing S...Solid-state batteries have received increasing attention in scientific and industrial communities,which benefits from the intrinsically safe solid electrolytes(SEs).Although much effort has been devoted to designing SEs with high ionic conductivities,it is extremely difficult to fully understand the ionic diffusion mechanisms in SEs through conventional experimental and theoretical methods.Herein,the temperature-dependent concerted diffusion mechanism of ions in SEs is explored through machinelearning molecular dynamics,taking Li_(10)GeP_(2)S_(12) as a prototype.Weaker diffusion anisotropy,more disordered Li distributions,and shorter residence time are observed at a higher temperature.Arrhenius-type temperature dependence is maintained within a wide temperature range,which is attributed to the linear temperature dependence of jump frequencies of various concerted diffusion modes.These results provide a theoretical framework to understand the ionic diffusion mechanisms in SEs and deepen the understanding of the chemical origin of temperature-dependent concerted diffusions in SEs.展开更多
Heteroatom-doped carbon materials have been widely used as sodium(Na) and potassium(K) metal anode frameworks to achieve uniform Na and K depositions. If the origin of the Sodiophilicity and potassiophilicity of dopin...Heteroatom-doped carbon materials have been widely used as sodium(Na) and potassium(K) metal anode frameworks to achieve uniform Na and K depositions. If the origin of the Sodiophilicity and potassiophilicity of doping sites in heteroatom-doped carbon host are clearly understood, the nucleation and growth behavior of Na and K can be precisely regulated in working batteries. Herein the Sodiophilicity and potassiophilicity chemistries of carbon materials are probed through first-principles calculations. The local dipole of doping functional groups and charge transfer during Na/K deposition are regarded as key principles to reveal the sodiophilic and potassiophilic nature of doping sites. Especially, O–B, O–S, and O–P co-doping strategy are predicted to be effective methods to improve the Sodiophilicity and potassiophilicity of carbon hosts and thus render safe and dendrite-free Na and K metal anodes. This work affords a deep and insightful understanding of Sodiophilicity and potassiophilicity chemistry of Na and K anodes and establishes general principles of designing highly sodiophilic and potassiophilic carbon frameworks.展开更多
The uniformity of current density distribution upon electrodes is one of the most important factors determining the lithium dendrites growth and cycling performance of lithium metal batteries(LMBs). Herein,current den...The uniformity of current density distribution upon electrodes is one of the most important factors determining the lithium dendrites growth and cycling performance of lithium metal batteries(LMBs). Herein,current density distributions of lithium metal anodes induced by various engineering factors, consisting of uneven cathode, electrolyte distribution, and different tab positions, and their effects on the electrochemical performance are investigated theoretically and experimentally in pouch cells. The deviation of current density in lithium metal anodes ranges from 2.47% to 196.18% due to the different levels of uneven cathode materials. However, the deviation is just 13.60% for different electrolyte thicknesses between cathodes and anodes, even a ten-layer separator in some positions. The maximum deviation for variational tab positions is only 0.17%. The nonuniformity in current density distribution results in severe dendrite growth issues and poor electrochemical performance of LMBs. This work not only confirms the direct correlation between the uneven current density distribution and lithium deposition behaviors, but also points out the decisive effects of cathode surface roughness on current distribution of anodes, to which more attentions should be paid in practical applications of LMBs.展开更多
Accelerating the development of agricultural cold chain logistics is of great significance to improve the competitiveness of agricultural products,increase rural incomes and ensure food security. The present situation...Accelerating the development of agricultural cold chain logistics is of great significance to improve the competitiveness of agricultural products,increase rural incomes and ensure food security. The present situation and main problems of agricultural cold chain logistics in Heilongjiang Province were analyzed from five aspects,such as the scale of construction,infrastructure,status quo of cold chain logistics technology,cold chain logistics enterprises and development environment,and proposed that Heilongjiang Province should focus on the development of poultry,fruit and vegetable,aquatic products,and processed food cold chain,then the strategic implementation measures for above areas were put forward.展开更多
Multiple cropping index(MCI)is a very important indicator in crop production and agricultural intensification,which represents the utilizing degree of agriculture resources at time scale and the effective utilization ...Multiple cropping index(MCI)is a very important indicator in crop production and agricultural intensification,which represents the utilizing degree of agriculture resources at time scale and the effective utilization situation of arable land.The objective of this paper is monitoring multiple cropping index of Henan province of China according to the time series of MODIS(Moderate-Resolution Imaging Spectroradiometer)EVI(Enhanced Vegetation Index)after Savitzky-Golay filter processing from the year 2006 to 2011.The results revealed that this method could provide an effective way to monitor multiple cropping index,and the method of no additional authentication data is independent and reliable.The result was accurate and stable,the slope of linear regression of the multiple cropping index between the statistical results and the remote sensing results was 1.0136(R2=0.779).The precision of sample areas validation was 97.91%.Suggesting that the time series MODIS-EVI which after Savitzky-Golay filtering processed,could provide an effective way to extract spatial information of multiple cropping index for management department of agriculture.展开更多
The number of people with Alzheimer’s disease(AD)is increasing annually,with the nidus mainly concentrated in the cortex and hippocampus.Despite of numerous efforts,effective treatment of AD is still facing great cha...The number of people with Alzheimer’s disease(AD)is increasing annually,with the nidus mainly concentrated in the cortex and hippocampus.Despite of numerous efforts,effective treatment of AD is still facing great challenges due to the blood brain barrier(BBB)and limited drug distribution in the AD nidus sites.Thus,in this study,using vinpocetine(VIN)as a model drug,the objective is to explore the feasibility of tackling the above bottleneck via intranasal drug delivery in combination with a brain guider,borneol(BOR),using nanoemulsion(NE)as the carrier.First of all,the NE were prepared and characterized.In vivo behavior of the NE after intranasal administration was investigated.Influence of BOR dose,BOR administration route on drug brain targeting behavior was evaluated,and the influence of BOR addition on drug brain subregion distribution was probed.It was demonstrated that all the NE had comparable size and similar retention behavior after intranasal delivery.Compared to intravenous injection,improved brain targeting effect was observed by intranasal route,and drug targeting index(DTI)of the VIN–NE group was 154.1%,with the nose-to-brain direct transport percentage(DTP)35.1%.Especially,remarkably enhanced brain distribution was achieved after BOR addition in the NE,with the extent depending on BOR dose.VIN brain concentration was the highest in the VIN-1-BOR-NE group at BOR dose of 1 mg/kg,with the DTI reaching 596.1%and the DTP increased to 83.1%.BOR could exert better nose to brain delivery when administrated together with the drug via intranasal route.Notably,BOR can remarkably enhance drug distribution in both hippocampus and cortex,the nidus areas of AD.In conclusion,in combination with intranasal delivery and the intrinsic brain guiding effect of BOR,drug distribution not only in the brain but also in the cortex and hippocampus can be enhanced significantly,providing the perquisite for improved therapeutic efficacy of AD.展开更多
基金National Key R&D Program of China(Grant No.2022YFB2703500)National Natural Science Foundation of China(Grant No.52277104)+2 种基金National Key R&D Program of Yunnan Province(202303AC100003)Applied Basic Research Foundation of Yunnan Province (202301AT070455, 202101AT070080)Revitalizing Talent Support Program of Yunnan Province (KKRD202204024).
文摘Constructing a cross-border power energy system with multiagent power energy as an alliance is important for studying cross-border power-trading markets.This study considers multiple neighboring countries in the form of alliances,introduces neighboring countries’exchange rates into the cross-border multi-agent power-trading market and proposes a method to study each agent’s dynamic decision-making behavior based on evolutionary game theory.To this end,this study uses three national agents as examples,constructs a tripartite evolutionary game model,and analyzes the evolution process of the decision-making behavior of each agent member state under the initial willingness value,cost of payment,and additional revenue of the alliance.This research helps realize cross-border energy operations so that the transaction agent can achieve greater trade profits and provides a theoretical basis for cooperation and stability between multiple agents.
基金This work is supposed by the Science and Technology Projects of China Southern Power Grid(YNKJXM20222402).
文摘Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice,which is of immense importance in mobilizing the entire society to reduce carbon emissions.The method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power grid.Therefore,it cannot provide carbon factor information beforehand.To address this issue,a prediction model based on the graph attention network is proposed.The model uses a graph structure that is suitable for the topology of the power grid and designs a supervised network using the loads of the grid nodes and the corresponding carbon factor data.The network extracts features and transmits information more suitable for the power system and can flexibly adjust the equivalent topology,thereby increasing the diversity of the structure.Its input and output data are simple,without the power grid parameters.We demonstrated its effect by testing IEEE-39 bus and IEEE-118 bus systems with average error rates of 2.46%and 2.51%.
基金supported by the National Key Research and Development Program (2016YFA0202500, 2015CB932500, and 2016YFA0200102)the National Natural Science Foundation of China (21676160, 21825501, 21805161, and 21808125)China Postdoctoral Science Foundation (2017M620773, 2018M631480, and BX201700125)
文摘Lithium (Li) metal with an ultrahigh specific theoretical capacity and the lowest reduction potential is strongly considered as a promising anode for high-energy-density batteries. However, uncontrolled lithium dendrites and infinite volume change during repeated plating/stripping cycles hinder its practical applications immensely. Herein, a house-like Li anode (housed Li) was designed to circumvent the above issues. The house matrix was composed of carbon fiber matrix and affords a stable structure to relieve the volume change. An artificial solid electrolyte layer was formed on composite Li metal, just like the roof of a house, which facilitates uniform Li ions diffusion and serves as a physical barrier against electrolyte corrosion. With the combination of solid electrolyte layer and matrix in the composite Li metal anode, both dendrite growth and volume expansion are remarkably inhibited. The housed Li|LiFePO4 batteries exhibited over 95% capacity retention after 500 cycles at 1.0 C in coin cell and 85% capacity retention after 80 cycles at 0.5 C in pouch cell. The rationally combination of solid electrolyte layer protection and housed framework in one Li metal anode sheds fresh insights on the design principle of a safe and long-lifespan Li metal anode for Li metal batteries.
基金supported by the National Key Research and Development Program (Nos. 2016YFA0202500 and 2016YFA0200102)National Natural Science Foundation of China (Nos. 21676160, 21825501, 21805161, 21808121, and U1801257)the Tsinghua University Initiative Scientific Research Program.
文摘Lithium(Li) metal anode has received extensive attentions due to its ultrahigh theoretical capacity and the most negative electrode potential. However, dendrite growth severely impedes the practical applications of the Li metal anode in rechargeable batteries. In this contribution, a mesoporous graphene with a high specific surface area was synthesized to host the Li metal anode. The mesoporous graphene host(MGH) has a high specific surface area(2090 m^2/g), which affords free space and an interconnected conductive pathway for Li plating and stripping, thus alleviating the volume variation and reducing the generation of dead Li during repeated cycles. More importantly, the high specific surface area of MGH efficiently reduces the local current density of the electrode, which favors a uniform Li nucleation and plating behavior, rendering a dendritefree deposition morphology at a low overpotential. These factors synergistically boost the Li utilization(90.1% vs. 70.1% for Cu foil) and life span(150 cycles vs. 100 cycles for Cu foil) with a low polarization of MGH electrode at an ultrahigh current of 15.0 mA/cm^2. The as-prepared MGH can provide fresh insights into the electrode design of the Li metal anode operating at high rates.
基金supported by the National Key Research and Development Program of China (2016YFC1102700)the National Natural Science Foundation of China (grant No.: 81771085, 81430011, 81600858, and 81600874)the Key projects of Sichuan Provincial Health and Family planning Commission (grant No.: 16ZD021)
文摘The biodiversity of the mycobiome,an important component of the oral microbial community,and the roles of fungal–bacterial and fungal–immune system interactions in the pathogenesis of oral lichen planus (OLP) remain largely uncharacterized.In this study,we sequenced the salivary mycobiome and bacteriome associated with OLP.First,we described the dysbiosis of the microbiome in OLP patients,which exhibits lower levels of fungi and higher levels of bacteria.Significantly higher abundances of the fungi Candida and Aspergillus in patients with reticular OLP and of Alternaria and Sclerotiniaceae_unidentified in patients with erosive OLP were observed compared to the healthy controls.Aspergillus was identified as an “OLP-associated” fungus because of its detection at a higher frequency than in the healthy controls.Second,the co-occurrence patterns of the salivary mycobiome–bacteriome demonstrated negative associations between specific fungal and bacterial taxa identified in the healthy controls,which diminished in the reticular OLP group and even became positive in the erosive OLP group.Moreover,the oral cavities of OLP patients were colonized by dysbiotic oral flora with lower ecological network complexity and decreased fungal–Firmicutes and increased fungal–Bacteroidetes sub-networks.Third,several keystone fungal genera (Bovista,Erysiphe,Psathyrella,etc.) demonstrated significant correlations with clinical scores and IL-17 levels.Thus,we established that fungal dysbiosis is associated with the aggravation of OLP.Fungal dysbiosis could alter the salivary bacteriome or may reflect a direct effect of host immunity,which participates in OLP pathogenesis.
基金supported by the National Natural Science Foundation of China(22061132002,U1801257,and 21825501)Russell Sage Foundation project(21-43-00006)+2 种基金the National Key Research and Development Program(2016YFA0200102 and 2016YFA0202500)Beijing Municipal Natural Science Foundation(Z20J00043)the Tsinghua University Initiative Scientific Research Program。
文摘Lithium(Li)metal anodes promise an ultrahigh theoretical energy density and low redox potential,thus being the critical energy material for next-generation batteries.Unfortunately,the formation of Li dendrites in Li metal anodes remarkably hinders the practical applications of Li metal anodes.Herein,the dynamic evolution of discrete Li dendrites and aggregated Li dendrites with increasing current densities is visualized by in-situ optical microscopy in conjunction with ex-situ scanning electron microscopy.As revealed by the phase field simulations,the formation of aggregated Li dendrites under high current density is attributed to the locally concentrated electric field rather than the depletion of Li ions.More specifically,the locally concentrated electric field stems from the spatial inhomogeneity on the Li metal surface and will be further enhanced with increasing current densities.Adjusting the above two factors with the help of the constructed phase field model is able to regulate the electrodeposited morphology from aggregated Li dendrites to discrete Li dendrites,and ultimately columnar Li morphology.The methodology and mechanistic understanding established herein give a significant step toward the practical applications of Li metal anodes.
基金supported by the National Natural Scientific Foundation of China(22109011)the China Postdoctoral Science Foundation(BX20200047,2021M690380)。
文摘Lithium metal batteries are the most promising choices for next-generation high-energy–density batteries. However, there is little mechanism understanding on lithium dendrite growth during lithium plating and the dead lithium(the main component of inactive lithium) formation during lithium stripping. This work proposed a phase field model to describe the lithium stripping process with dead lithium formation.The coupling of galvanostatic conditions enables the phase field method to accurately match experimental results. The factors influencing the dead lithium formation on the increasing discharge polarization are revealed. Besides, the simulation of the battery polarization curve, the capacity loss peak, and the Coulomb efficiency is realized. This contribution affords an insightful understanding on dead lithium formation with phase field methods, which can contribute general principles on rational design of lithium metal batteries.
基金supported by the National Natural Science Foundation of China(Project No.42171361)the Research Grants Council of the Hong Kong Special Administrative Region,China,under Project PolyU 25211819the Hong Kong Polytechnic University under Projects 1-ZE8E and 1-ZVN6.
文摘Light detection and ranging(LiDAR)has contributed immensely to forest mapping and 3D tree modelling.From the perspective of data acquisition,the integration of LiDAR data from different platforms would enrich forest information at the tree and plot levels.This research develops a general framework to integrate ground-based and UAV-LiDAR(ULS)data to better estimate tree parameters based on quantitative structure modelling(QSM).This is accomplished in three sequential steps.First,the ground-based/ULS LiDAR data were co-registered based on the local density peaks of the clustered canopy.Next,redundancy and noise were removed for the ground-based/ULS LiDAR data fusion.Finally,tree modeling and biophysical parameter retrieval were based on QSM.Experiments were performed for Backpack/Handheld/UAV-based multi-platform mobile LiDAR data of a subtropical forest,including poplar and dawn redwood species.Generally,ground-based/ULS LiDAR data fusion outperforms ground-based LiDAR with respect to tree parameter estimation compared to field data.The fusion-derived tree height,tree volume,and crown volume significantly improved by up to 9.01%,5.28%,and 18.61%,respectively,in terms of rRMSE.By contrast,the diameter at breast height(DBH)is the parameter that has the least benefits from fusion,and rRMSE remains approximately the same,because stems are already well sampled from ground data.Additionally,particularly for dense forests,the fusion-derived tree parameters were improved compared to those derived from ground-based LiDAR.Ground-based LiDAR can potentially be used to estimate tree parameters in low-stand-density forests,whereby the improvement owing to fusion is not significant.
基金supported by Beijing Natural Science Foundation(JQ20004)National Key Research and Development Program(2021YFB2400300)+1 种基金National Natural Scientific Foundation of China(22109011)the China Postdoctoral Science Foundation(BX20200047,2021M690380)。
文摘Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of practical lithium metal batteries.Methods of driving lithium metal to deposit inside the pores of structured lithium metal anodes have always been one of the most concerned issues,especially for highly conductive frameworks.An electrochemical phase field theory with galvanostatic lithium plating process is employed in this work,the mechanism that illustrates the preference of lithium metal to deposit at the top of the framework structure has been revealed,and through the simulation analysis of various regulating strategies,the strategies that can efficiently drive lithium to deposit inside structured pores are summarized.This work presents the theoretical calculation and analysis methods that can be used for the rational design of lithium metal batteries.
基金supported by the National Key Research and Development Program(2021YFB2500210)the Beijing Municipal Natural Science Foundation(Z20J00043)+4 种基金the National Natural Science Foundation of China(22109086 and 21825501)the China Postdoctoral Science Foundation(2021TQ0161 and 2021 M691709)the Guoqiang Institute at Tsinghua University(2020GQG1006)the support from the Shuimu Tsinghua Scholar Program of Tsinghua Universitythe support from the Tsinghua National Laboratory for Information Science and Technology for theoretical simulations。
文摘Solid-state batteries have received increasing attention in scientific and industrial communities,which benefits from the intrinsically safe solid electrolytes(SEs).Although much effort has been devoted to designing SEs with high ionic conductivities,it is extremely difficult to fully understand the ionic diffusion mechanisms in SEs through conventional experimental and theoretical methods.Herein,the temperature-dependent concerted diffusion mechanism of ions in SEs is explored through machinelearning molecular dynamics,taking Li_(10)GeP_(2)S_(12) as a prototype.Weaker diffusion anisotropy,more disordered Li distributions,and shorter residence time are observed at a higher temperature.Arrhenius-type temperature dependence is maintained within a wide temperature range,which is attributed to the linear temperature dependence of jump frequencies of various concerted diffusion modes.These results provide a theoretical framework to understand the ionic diffusion mechanisms in SEs and deepen the understanding of the chemical origin of temperature-dependent concerted diffusions in SEs.
基金supported by the National Key Research and Development Program(2016YFA0202500)the National Natural Science Foundation of China(21825501)the Tsinghua University Initiative Scientific Research Program。
文摘Heteroatom-doped carbon materials have been widely used as sodium(Na) and potassium(K) metal anode frameworks to achieve uniform Na and K depositions. If the origin of the Sodiophilicity and potassiophilicity of doping sites in heteroatom-doped carbon host are clearly understood, the nucleation and growth behavior of Na and K can be precisely regulated in working batteries. Herein the Sodiophilicity and potassiophilicity chemistries of carbon materials are probed through first-principles calculations. The local dipole of doping functional groups and charge transfer during Na/K deposition are regarded as key principles to reveal the sodiophilic and potassiophilic nature of doping sites. Especially, O–B, O–S, and O–P co-doping strategy are predicted to be effective methods to improve the Sodiophilicity and potassiophilicity of carbon hosts and thus render safe and dendrite-free Na and K metal anodes. This work affords a deep and insightful understanding of Sodiophilicity and potassiophilicity chemistry of Na and K anodes and establishes general principles of designing highly sodiophilic and potassiophilic carbon frameworks.
基金supported by the National Natural Science Foundation of China (22075029, 22179070, U1932220)。
文摘The uniformity of current density distribution upon electrodes is one of the most important factors determining the lithium dendrites growth and cycling performance of lithium metal batteries(LMBs). Herein,current density distributions of lithium metal anodes induced by various engineering factors, consisting of uneven cathode, electrolyte distribution, and different tab positions, and their effects on the electrochemical performance are investigated theoretically and experimentally in pouch cells. The deviation of current density in lithium metal anodes ranges from 2.47% to 196.18% due to the different levels of uneven cathode materials. However, the deviation is just 13.60% for different electrolyte thicknesses between cathodes and anodes, even a ten-layer separator in some positions. The maximum deviation for variational tab positions is only 0.17%. The nonuniformity in current density distribution results in severe dendrite growth issues and poor electrochemical performance of LMBs. This work not only confirms the direct correlation between the uneven current density distribution and lithium deposition behaviors, but also points out the decisive effects of cathode surface roughness on current distribution of anodes, to which more attentions should be paid in practical applications of LMBs.
基金Supported by the Soft Science Project of Science and Technology Program of Heilongjiang Province in 2012 (GC12D112)Humanities and Social Science Program of Department of Education of Heilongjiang Province in 2013 (12532075)Humanities and Social Science Foundation of the Ministry of Education (10YJA630070)
文摘Accelerating the development of agricultural cold chain logistics is of great significance to improve the competitiveness of agricultural products,increase rural incomes and ensure food security. The present situation and main problems of agricultural cold chain logistics in Heilongjiang Province were analyzed from five aspects,such as the scale of construction,infrastructure,status quo of cold chain logistics technology,cold chain logistics enterprises and development environment,and proposed that Heilongjiang Province should focus on the development of poultry,fruit and vegetable,aquatic products,and processed food cold chain,then the strategic implementation measures for above areas were put forward.
基金This work is supported by National Natural Science Foundation of China(Project No.518092509)Science and Technology Service Network Initiative(STS)of the Chinese Academy of Sciences(Project No.KFJ-STS-ZDTP-009)Open Foundation of The Ministry of Water Resources Key Laboratory of Soil and Water Loss Process and Control in the Loess Plateau(Project No.2017004).
文摘Multiple cropping index(MCI)is a very important indicator in crop production and agricultural intensification,which represents the utilizing degree of agriculture resources at time scale and the effective utilization situation of arable land.The objective of this paper is monitoring multiple cropping index of Henan province of China according to the time series of MODIS(Moderate-Resolution Imaging Spectroradiometer)EVI(Enhanced Vegetation Index)after Savitzky-Golay filter processing from the year 2006 to 2011.The results revealed that this method could provide an effective way to monitor multiple cropping index,and the method of no additional authentication data is independent and reliable.The result was accurate and stable,the slope of linear regression of the multiple cropping index between the statistical results and the remote sensing results was 1.0136(R2=0.779).The precision of sample areas validation was 97.91%.Suggesting that the time series MODIS-EVI which after Savitzky-Golay filtering processed,could provide an effective way to extract spatial information of multiple cropping index for management department of agriculture.
基金supported by the Distinguished Professor Project of Liaoning Province.
文摘The number of people with Alzheimer’s disease(AD)is increasing annually,with the nidus mainly concentrated in the cortex and hippocampus.Despite of numerous efforts,effective treatment of AD is still facing great challenges due to the blood brain barrier(BBB)and limited drug distribution in the AD nidus sites.Thus,in this study,using vinpocetine(VIN)as a model drug,the objective is to explore the feasibility of tackling the above bottleneck via intranasal drug delivery in combination with a brain guider,borneol(BOR),using nanoemulsion(NE)as the carrier.First of all,the NE were prepared and characterized.In vivo behavior of the NE after intranasal administration was investigated.Influence of BOR dose,BOR administration route on drug brain targeting behavior was evaluated,and the influence of BOR addition on drug brain subregion distribution was probed.It was demonstrated that all the NE had comparable size and similar retention behavior after intranasal delivery.Compared to intravenous injection,improved brain targeting effect was observed by intranasal route,and drug targeting index(DTI)of the VIN–NE group was 154.1%,with the nose-to-brain direct transport percentage(DTP)35.1%.Especially,remarkably enhanced brain distribution was achieved after BOR addition in the NE,with the extent depending on BOR dose.VIN brain concentration was the highest in the VIN-1-BOR-NE group at BOR dose of 1 mg/kg,with the DTI reaching 596.1%and the DTP increased to 83.1%.BOR could exert better nose to brain delivery when administrated together with the drug via intranasal route.Notably,BOR can remarkably enhance drug distribution in both hippocampus and cortex,the nidus areas of AD.In conclusion,in combination with intranasal delivery and the intrinsic brain guiding effect of BOR,drug distribution not only in the brain but also in the cortex and hippocampus can be enhanced significantly,providing the perquisite for improved therapeutic efficacy of AD.
