Cost-effective atomically dispersed Fe-N-P-C complex catalysts are promising to catalyze the oxygen reduction reaction(ORR)and replace Pt catalysts in fuel cells and metal-air batteries.However,it remains a challenge ...Cost-effective atomically dispersed Fe-N-P-C complex catalysts are promising to catalyze the oxygen reduction reaction(ORR)and replace Pt catalysts in fuel cells and metal-air batteries.However,it remains a challenge to increase the number of atomically dispersed active sites on these catalysts.Here we report a highly efficient impregnation-pyrolysis method to prepare effective ORR electrocatalysts with large amount of atomically dispersed Fe active sites from biomass.Two types of active catalyst centers were identified,namely atomically dispersed Fe sites and Fe_(x)P particles.The ORR rate of the atomically dispersed Fe sites is three orders of magnitude higher than it of Fe_(x)P particles.A linear correlation between the amount of the atomically dispersed Fe and the ORR activity was obtained,revealing the major contribution of the atomically dispersed Fe to the ORR activity.The number of atomically dispersed Fe increases as the Fe loading increased and reaching the maximum at 1.86 wt%Fe,resulting in the maximum ORR rate.Optimized Fe-N-P-C complex catalyst was used as the cathode catalyst in a homemade Zn-air battery and good performance of an energy density of 771 Wh kgZn^(-1),a power density of 92.9 m W cm^(-2) at 137 m A cm^(-2) and an excellent durability were exhibited.展开更多
Objective: To evaluate the anti-arthritic effects of Polygonatum kingianum rhizome extract using both in vitro and in vivo models.Methods: Lipopolysaccharide-induced RAW 264.7 macrophages were treated with an ethanol ...Objective: To evaluate the anti-arthritic effects of Polygonatum kingianum rhizome extract using both in vitro and in vivo models.Methods: Lipopolysaccharide-induced RAW 264.7 macrophages were treated with an ethanol extract of Polygonatum kingianum rhizomes at different concentrations to determine nitric oxide and prostaglandin E2(PGE2) production. For in vivo study, Polygonatum kingianum ethanol extract was further investigated for its antiinflammatory effect in a mouse model with collagen antibodyinduced arthritis. Phytochemical study of Polygonatum kingianum ethanol extract was also performed.Results: Saponins(142 mg/g total yield) was the main component in the Polygonatum kingianum ethanol extract. 5α,8α-ergosterol peroxide,(E,E)-9-oxooctadeca-10,12-dienoic acid and 3-(2?-hydroxy-4?-methoxy-benzyl)-5,7-dihydroxy-8-methyl-chroman-4-one were isolated from the extract. Polygonatum kingianum ethanol extract exhibited potential anti-inflammatory effects by inhibiting nitric oxide and PGE2 production in RAW 264.7 cells in a dosedependent manner. The level of arthritis in mice with collagen antibody-induced arthritis was significantly reduced(P<0.01) after treatment with Polygonatum kingianum ethanol extract, particularly at a dose of 1 000 mg/kg body weight. Besides, the extract demonstrated the regulatory effects on serum tumor necrosis factoralpha, interleukin-6, and interleukin-10 in treated mice.Conclusions: Polygonatum kingianum ethanol extract has beneficial effects on inflammatory cytokine regulation and PGE2 inhibition in an experimental mouse model with collagen antibody-induced arthritis. The phytochemical screening reveals that the saponin, as the main component, and sterols(daucosterol and 5α,8α-ergosterol peroxide) from Polygonatum kingianum ethanol extract may contribute to its promising in vitro and in vivo anti-inflammatory activities.展开更多
Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer effic...Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer efficiency for photocatalysts.Herein,a new 2 D/2 D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core photocatalyst(DLWS/Nb_(2)O_(5))is designed.The atom-resolved HAADF-STEM results unravel the presence of an unusual 2 D/2 D shell/core interface in DLWS/Nb_(2)O_(5).Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra,the average lifetime of charge carriers for DLWS/Nb_(2)O_(5)(180.97 ps)is considerably shortened as compared to that of Nb_(2)O_(5)(230.50 ps),strongly indicating that the 2 D/2 D shell/core interface enables DLWS/Nb_(2)O_(5)to achieve ultrafast charge transfer from Nb_(2)O_(5)to atomic double-layer WS_(2),thus yielding a high photocatalytic H_(2)evolution rate of 237.6 mmol/h,up to10.8 times higher than that of pure Nb_(2)O_(5)nanosheet.This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.展开更多
Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. Th...Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. This letter reports a dropout neuronal unit(1R1T-DNU) based on one memristor–one electrolyte-gated transistor with an ultralow energy consumption of 25 p J/spike. A dropout neural network is constructed based on such a device and has been verified by MNIST dataset, demonstrating high recognition accuracies(> 90%) within a large range of dropout probabilities up to40%. The running time can be reduced by increasing dropout probability without a significant loss in accuracy. Our results indicate the great potential of introducing such 1R1T-DNUs in full-hardware neural networks to enhance energy efficiency and to solve the overfitting problem.展开更多
干扰对齐(interference alignment,IA)作为极具潜力的干扰管理策略,能获得与用户数量成线性关系的自由度增益,但因其需要全局实时信道状态信息(channel state information,CSI)才能有效实现,使得IA理论向实用的转化将面临众多挑战。针...干扰对齐(interference alignment,IA)作为极具潜力的干扰管理策略,能获得与用户数量成线性关系的自由度增益,但因其需要全局实时信道状态信息(channel state information,CSI)才能有效实现,使得IA理论向实用的转化将面临众多挑战。针对该问题,本文基于多小区蜂窝系统,提出了一种基于线性弥散空时码的有限反馈干扰对齐算法,该算法将预编码和线性弥散空时码编码进行级联,在只需反馈单个用户CSI的条件下,通过合理地设计预编码矩阵、线性弥散空时码块以及接收端的接收矩阵,来实现干扰的完全消除。仿真结果表明,相比已有研究,新IA算法在实现干扰完全消除的情况下,能够极大地降低系统CSI反馈开销。展开更多
In traditional server clusters,high hardware costs associated with basic network infrastructure have hindered the system’s ability to meet the stringent performance requirements for data-intensive workloads.To addres...In traditional server clusters,high hardware costs associated with basic network infrastructure have hindered the system’s ability to meet the stringent performance requirements for data-intensive workloads.To address the limitations of data transmission in such circumstances,we propose TxCocket,an innovative solution for cross-node data transmission based on Compute Express Link(CXL)memory sharing.TxCocket leverages self-developed memory pooling hardware,utilizing CXL shared memory as the medium for data transmission.This approach enables efficient,secure and reliable cross-node transmission.Our test results indicate that TxCocket significantly reduces transmission latency and achieves effective throughput comparable to a 200Gb network interface card(NIC),while costing only 18.7%of conventional network solutions.As the first comprehensive solution for CXL memory sharing,TxCocket effectively circumvents the limitations of CXL 1.1 Specification.Furthermore,with its high performance and cost efficiency,TxCocket certainly demonstrates a very promising architecture for future evolution of intelligent data center.展开更多
Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-stat...Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-state lifetime.Different from the fluorescence,phosphorescence,thermally activated delayed fluorescence(TADF),and organic radical materials traditionally used in OLEDs,we demonstrate herein a new type of emitter,cerium(Ⅲ)complex Ce-1 with spin-allowed and parity-allowed d-f transition of the centre Ce^(3+) ion.The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns,which is considerably faster than that achieved in efficient phosphorescence and TADF emitters.The optimized OLEDs show an average maximum external quantum efficiency(EQE)of 12.4% and Commission Internationale de L’Eclairage(CIE)coordinates of(0.146,0.078).展开更多
基金the Yunnan Engineering Research Center Innovation Ability Construction and Enhancement Projects[2023-XMDJ-00617107]Natural Science Foundation of Yunnan Province[202401AS070646]Natural Science Foundation of Jiangxi Provincial[20232BAB214038].
文摘Despite progress in suppressing polysulfide shuttling,this challenge persists in lithium-sulfur battery commercialization.While existing strategies emphasize polysulfide adsorption and catalytic conversion,the critical role of diffusion kinetics in conversion–deposition processes remains underexplored.We design an MXene-based array architecture integrating 2D structural advantages and strong polysulfide affinity to regulate diffusion pathways.Combined experimental and multiscale computational studies reveal diffusion-mediated conversion-deposition dynamics.The sodium alginate-constructed MXene array enables three synergistic mechanisms:(1)Enhanced ion/electron delocalization reduces diffusion barriers,(2)Continuous ion transport channels facilitate charge transfer,and(3)Exposed polar surfaces promote polysulfide aggregation/conversion.Synchrotron X-ray tomography coupled with comprehensive electrochemical analyses reveals distinct mechanistic differences between conversion and deposition processes arising from diffusion heterogeneity.In situ characterization techniques combined with DFT simulation calculations demonstrate that diffusion kinetics exerts differential regulatory effects on these coupled electrochemical processes,exhibiting particular sensitivity toward the deposition mechanism.This work provides fundamental insights that reshape our understanding of diffusion-mediated phase transformation in complex multi-step electrochemical systems,offering new perspectives for advanced electrode architecture design in next-generation energy storage technologies.
基金The financial supports from Department of Chemical Engineeringthe support from China Scholarship Council(CSC)for his study at NTNU。
文摘Cost-effective atomically dispersed Fe-N-P-C complex catalysts are promising to catalyze the oxygen reduction reaction(ORR)and replace Pt catalysts in fuel cells and metal-air batteries.However,it remains a challenge to increase the number of atomically dispersed active sites on these catalysts.Here we report a highly efficient impregnation-pyrolysis method to prepare effective ORR electrocatalysts with large amount of atomically dispersed Fe active sites from biomass.Two types of active catalyst centers were identified,namely atomically dispersed Fe sites and Fe_(x)P particles.The ORR rate of the atomically dispersed Fe sites is three orders of magnitude higher than it of Fe_(x)P particles.A linear correlation between the amount of the atomically dispersed Fe and the ORR activity was obtained,revealing the major contribution of the atomically dispersed Fe to the ORR activity.The number of atomically dispersed Fe increases as the Fe loading increased and reaching the maximum at 1.86 wt%Fe,resulting in the maximum ORR rate.Optimized Fe-N-P-C complex catalyst was used as the cathode catalyst in a homemade Zn-air battery and good performance of an energy density of 771 Wh kgZn^(-1),a power density of 92.9 m W cm^(-2) at 137 m A cm^(-2) and an excellent durability were exhibited.
基金supported by the Graduate University of Science and Technology,Vietnam Academy of Science and Technology for financial support(Grant No GUST.STS.DT 2017-HH13)
文摘Objective: To evaluate the anti-arthritic effects of Polygonatum kingianum rhizome extract using both in vitro and in vivo models.Methods: Lipopolysaccharide-induced RAW 264.7 macrophages were treated with an ethanol extract of Polygonatum kingianum rhizomes at different concentrations to determine nitric oxide and prostaglandin E2(PGE2) production. For in vivo study, Polygonatum kingianum ethanol extract was further investigated for its antiinflammatory effect in a mouse model with collagen antibodyinduced arthritis. Phytochemical study of Polygonatum kingianum ethanol extract was also performed.Results: Saponins(142 mg/g total yield) was the main component in the Polygonatum kingianum ethanol extract. 5α,8α-ergosterol peroxide,(E,E)-9-oxooctadeca-10,12-dienoic acid and 3-(2?-hydroxy-4?-methoxy-benzyl)-5,7-dihydroxy-8-methyl-chroman-4-one were isolated from the extract. Polygonatum kingianum ethanol extract exhibited potential anti-inflammatory effects by inhibiting nitric oxide and PGE2 production in RAW 264.7 cells in a dosedependent manner. The level of arthritis in mice with collagen antibody-induced arthritis was significantly reduced(P<0.01) after treatment with Polygonatum kingianum ethanol extract, particularly at a dose of 1 000 mg/kg body weight. Besides, the extract demonstrated the regulatory effects on serum tumor necrosis factoralpha, interleukin-6, and interleukin-10 in treated mice.Conclusions: Polygonatum kingianum ethanol extract has beneficial effects on inflammatory cytokine regulation and PGE2 inhibition in an experimental mouse model with collagen antibody-induced arthritis. The phytochemical screening reveals that the saponin, as the main component, and sterols(daucosterol and 5α,8α-ergosterol peroxide) from Polygonatum kingianum ethanol extract may contribute to its promising in vitro and in vivo anti-inflammatory activities.
基金funded by the China Postdoctoral Science Foundation(pre-station,No.2019TQ0050)Applied Basic Research Program of Sichuan Province(No.2020YJ0068)+5 种基金the China Postdoctoral Science Foundation(No.2020M673186)National Natural Science Foundation of China(No.22002014)National Natural Science Foundation of China(No.11804248)the financial support from the National Natural Science Foundation of China(No.21971113)Natural Science Foundation of Tianjin(No.18JCQNJC03200)supported by MOE Tier 1 RG4/17 and MOE Tier 2 MOE2019-T2-2-105。
文摘Low-efficiency charge transfer is a critical factor to limit the photocatalytic H_(2)evolution activity of semiconductor photocatalysts.The interface design is a promising approach to achieve high chargetransfer efficiency for photocatalysts.Herein,a new 2 D/2 D atomic double-layer WS_(2)/Nb_(2)O_(5)shell/core photocatalyst(DLWS/Nb_(2)O_(5))is designed.The atom-resolved HAADF-STEM results unravel the presence of an unusual 2 D/2 D shell/core interface in DLWS/Nb_(2)O_(5).Taking advantage of the advanced femtosecond-resolved ultrafast TAS spectra,the average lifetime of charge carriers for DLWS/Nb_(2)O_(5)(180.97 ps)is considerably shortened as compared to that of Nb_(2)O_(5)(230.50 ps),strongly indicating that the 2 D/2 D shell/core interface enables DLWS/Nb_(2)O_(5)to achieve ultrafast charge transfer from Nb_(2)O_(5)to atomic double-layer WS_(2),thus yielding a high photocatalytic H_(2)evolution rate of 237.6 mmol/h,up to10.8 times higher than that of pure Nb_(2)O_(5)nanosheet.This study will open a new window for the development of high-efficient photocatalytic systems through the interface design.
基金Project supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1202600 and 2023YFE0208600)in part by the National Natural Science Foundation of China (Grant Nos. 62174082, 92364106, 61921005, 92364204, and 62074075)。
文摘Artificial neural networks(ANN) have been extensively researched due to their significant energy-saving benefits.Hardware implementations of ANN with dropout function would be able to avoid the overfitting problem. This letter reports a dropout neuronal unit(1R1T-DNU) based on one memristor–one electrolyte-gated transistor with an ultralow energy consumption of 25 p J/spike. A dropout neural network is constructed based on such a device and has been verified by MNIST dataset, demonstrating high recognition accuracies(> 90%) within a large range of dropout probabilities up to40%. The running time can be reduced by increasing dropout probability without a significant loss in accuracy. Our results indicate the great potential of introducing such 1R1T-DNUs in full-hardware neural networks to enhance energy efficiency and to solve the overfitting problem.
文摘干扰对齐(interference alignment,IA)作为极具潜力的干扰管理策略,能获得与用户数量成线性关系的自由度增益,但因其需要全局实时信道状态信息(channel state information,CSI)才能有效实现,使得IA理论向实用的转化将面临众多挑战。针对该问题,本文基于多小区蜂窝系统,提出了一种基于线性弥散空时码的有限反馈干扰对齐算法,该算法将预编码和线性弥散空时码编码进行级联,在只需反馈单个用户CSI的条件下,通过合理地设计预编码矩阵、线性弥散空时码块以及接收端的接收矩阵,来实现干扰的完全消除。仿真结果表明,相比已有研究,新IA算法在实现干扰完全消除的情况下,能够极大地降低系统CSI反馈开销。
文摘In traditional server clusters,high hardware costs associated with basic network infrastructure have hindered the system’s ability to meet the stringent performance requirements for data-intensive workloads.To address the limitations of data transmission in such circumstances,we propose TxCocket,an innovative solution for cross-node data transmission based on Compute Express Link(CXL)memory sharing.TxCocket leverages self-developed memory pooling hardware,utilizing CXL shared memory as the medium for data transmission.This approach enables efficient,secure and reliable cross-node transmission.Our test results indicate that TxCocket significantly reduces transmission latency and achieves effective throughput comparable to a 200Gb network interface card(NIC),while costing only 18.7%of conventional network solutions.As the first comprehensive solution for CXL memory sharing,TxCocket effectively circumvents the limitations of CXL 1.1 Specification.Furthermore,with its high performance and cost efficiency,TxCocket certainly demonstrates a very promising architecture for future evolution of intelligent data center.
基金the financial support from the National Key R&D Programme of China(Nos.2017YFA0205100,2016YFB0401001)the Beijing Natural Science Foundation(2202015)+1 种基金financial support from the China Postdoctoral Science Foundation(2018M641065)supported by the high-performance computing platform of Peking University.
文摘Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-state lifetime.Different from the fluorescence,phosphorescence,thermally activated delayed fluorescence(TADF),and organic radical materials traditionally used in OLEDs,we demonstrate herein a new type of emitter,cerium(Ⅲ)complex Ce-1 with spin-allowed and parity-allowed d-f transition of the centre Ce^(3+) ion.The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns,which is considerably faster than that achieved in efficient phosphorescence and TADF emitters.The optimized OLEDs show an average maximum external quantum efficiency(EQE)of 12.4% and Commission Internationale de L’Eclairage(CIE)coordinates of(0.146,0.078).
