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“21·11”极端暴雪过程多系统结构演变及热动力机制 被引量:3
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作者 齐道日娜 何立富 张乐英 《气象》 CSCD 北大核心 2024年第1期18-32,共15页
利用多种实时观测资料和ERA5再分析资料,对造成2021年11月6—8日华北、东北极端暴雪过程多系统的结构特征及热动力机制进行分析。结果表明:此次过程先后由500 hPa高空横槽、河套西风槽及高空冷涡接力影响,其上空的高空急流不断加强并呈... 利用多种实时观测资料和ERA5再分析资料,对造成2021年11月6—8日华北、东北极端暴雪过程多系统的结构特征及热动力机制进行分析。结果表明:此次过程先后由500 hPa高空横槽、河套西风槽及高空冷涡接力影响,其上空的高空急流不断加强并呈现“S”型弯曲,同时低空偏南风急流形成与加强,并在东北地区与高空急流耦合。此次过程阶段性特征明显,其影响系统的结构特征和水汽输送存在差异。回流冷锋形成的冷垫锋面较为浅薄,暖湿气流在其上倾斜上升。寒潮冷锋则较为陡立,上升气流随高度西倾。而锋面气旋结构较为深厚直立,使得气流呈垂直上升运动。随着斜压强迫的不断增强,850 hPa切变线由准东西向分布转为南北向分布,再演变为低涡切变结构。对应的水平涡度由弱转强,其上空正涡度垂直分布也逐渐加强,由弱倾斜上升运动逐步演变为较强垂直上升运动区,并在系统东侧形成次级环流下沉支。此次过程的发生发展与锋生作用密切相关,降雪落区和强度与锋区走向及锋生函数大小较为一致。假相当位温锋区在降雪3个阶段逐渐加强,垂直锋区和低层锋生函数由倾斜状态演变为近乎直立结构;湿位涡诊断表明,3个阶段降雪落区均发生在湿位涡正压项>0而斜压项<0配置的区域,条件性对称不稳定是此次过程的主要动力机制。 展开更多
关键词 多系统结构 地面气旋 斜压强迫 条件对称不稳定 动力锋生
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Modifying the pore structure of biomass-derived porous carbon for use in energy storage systems
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作者 XIE Bin ZHAO Xin-ya +5 位作者 MA Zheng-dong ZHANG Yi-jian DONG Jia-rong WANG Yan BAI Qiu-hong SHEN Ye-hua 《新型炭材料(中英文)》 北大核心 2025年第4期870-888,共19页
The development of sustainable electrode materials for energy storage systems has become very important and porous carbons derived from biomass have become an important candidate because of their tunable pore structur... The development of sustainable electrode materials for energy storage systems has become very important and porous carbons derived from biomass have become an important candidate because of their tunable pore structure,environmental friendliness,and cost-effectiveness.Recent advances in controlling the pore structure of these carbons and its relationship between to is energy storage performance are discussed,emphasizing the critical role of a balanced distribution of micropores,mesopores and macropores in determining electrochemical behavior.Particular attention is given to how the intrinsic components of biomass precursors(lignin,cellulose,and hemicellulose)influence pore formation during carbonization.Carbonization and activation strategies to precisely control the pore structure are introduced.Finally,key challenges in the industrial production of these carbons are outlined,and future research directions are proposed.These include the establishment of a database of biomass intrinsic structures and machine learning-assisted pore structure engineering,aimed at providing guidance for the design of high-performance carbon materials for next-generation energy storage devices. 展开更多
关键词 Energy storage systems Porous carbon Biomass precursors Pore structure Machine learning-assisted
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Consensus tracking protocol and formation control of multi-agent systems with switching topology 被引量:13
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作者 年晓红 苏赛军 潘欢 《Journal of Central South University》 SCIE EI CAS 2011年第4期1178-1183,共6页
Consensus tracking control problems for single-integrator dynamics of multi-agent systems with switching topology are investigated. In order to design effective consensus tracking protocols for a more general class of... Consensus tracking control problems for single-integrator dynamics of multi-agent systems with switching topology are investigated. In order to design effective consensus tracking protocols for a more general class of networks, which are aimed at ensuring that the concerned states of agents converge to a constant or time-varying reference state, new consensus tracking protocols with a constant and time-varying reference state are proposed, respectively. Particularly, by contrast with spanning tree, an improved condition of switching interaction topology is presented. And then, convergence analysis of two consensus tracking protocols is provided by Lyapunov stability theory. Moreover, consensus tracking protocol with a time-varying reference state is extended to achieve the fbrmation control. By introducing formation structure set, each agent can gain its individual desired trajectory. Finally, several simulations are worked out to illustrate the effectiveness of theoretical results. The test results show that the states of agents can converge to a desired constant or time-varying reference state. In addition, by selecting appropriate structure set, agents can maintain the expected formation under random switching interaction topologies. 展开更多
关键词 multi-agent system consensus protocols formation control switching topology
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Extended consensus analysis of multi-agent systems with switching topologies
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作者 潘欢 年晓红 郭凌 《Journal of Central South University》 SCIE EI CAS 2012年第6期1564-1569,共6页
Theoretical analysis of consensus for networked multi-agent systems with switching topologies was conducted.Supposing that information-exchange topologies of networked system are dynamic,a modified linear protocol is ... Theoretical analysis of consensus for networked multi-agent systems with switching topologies was conducted.Supposing that information-exchange topologies of networked system are dynamic,a modified linear protocol is proffered which is more practical than existing ones.The definition of trajectory consensus is given and a new consensus protocol is exhibited such that multi-agent system achieves trajectory consensus.In addition,a formation control strategy is designed.A common Lyapunov function is proposed to analyze the consensus convergence of networked multi-agent systems with switching topologies.Simulations are provided to demonstrate the effectiveness of the theoretical results. 展开更多
关键词 networked multi-agent systems consensus problem switching topologies M-MATRIX
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