Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical...Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical patterns and processes,and highlight the integration of multiple disciplines.In this paper,we discussed the problems and challenges that landscape ecology is currently facing,emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes.We suggested that the focus should be on the integration of ground-based observation,mobile monitoring,transect survey,and remote-sensing monitoring,as well as improved coupling of experimental and model simulations.In addition,we outlined the research frontiers in landscape ecology,including scaling,integrated pattern and process modeling,and regional synthesis.Lastly,a brief review of pat-tern-process-scale coupling studies in China was provided.We concluded by pointing out that pattern-process-scale interactions,correlations between natural,economic,and social processes,and the coupling of human and natural systems will be major research areas in landscape ecology in the future.展开更多
Cp2Yb·2THF reacts with CpNa in 1:1 molar ratio in THF at 40℃ for 2 h, and the in situ generated ani-onic divalent complex NaYbCp3(THF)n reacts further with an excess of CpH at 40℃ for 48 h, after work-up, affor...Cp2Yb·2THF reacts with CpNa in 1:1 molar ratio in THF at 40℃ for 2 h, and the in situ generated ani-onic divalent complex NaYbCp3(THF)n reacts further with an excess of CpH at 40℃ for 48 h, after work-up, affording the trivalent anionic ytterbium complex [Na(THF)2(μ2-η5-Cp) (η5,η5,η1-Cp3Yb)(THF)]n (1) by oxidation reaction of Cp2Yb with CpH. Crystal structure determination reveals that com-plex 1 has one-dimension polymeric chains of distinct Na(THF)2(μ2-η5-Cp)(η5,η5,η1-Cp3Yb)(THF) units, which were formed by the coordination of the bridging Cp ligand with Cp3Yb·THF and Na(THF)2 in η5,η5 mode via self-assembly.展开更多
Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, m...Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, many of them are safety-critical, and therefore are required to meet a critical safety standard. Invariant generation plays a central role in the verification and synthesis of hybrid systems. In the previous work, the fourth author and his coauthors gave a necessary and sufficient condition for a semi-algebraic set being an invariant of a polynomial autonomous dynamical system, which gave a confirmative answer to the open problem. In addition, based on which a complete algorithm for generating all semi-algebraic invariants of a given polynomial autonomous hybrid system with the given shape was proposed. This paper considers how to extend their work to non-autonomous dynamical and hybrid systems. Non-autonomous dynamical and hybrid systems are with inputs, which are very common in practice; in contrast, autonomous ones are without inputs. Furthermore, the authors present a sound and complete algorithm to verify semi-algebraic invariants for non-autonomous polynomial hybrid systems. Based on which, the authors propose a sound and complete algorithm to generate all invariants with a pre-defined template.展开更多
基金Under the auspices of National Natural Science Foundation of China (No.40930528)State Forestry Administration of China (No.201004058)
文摘Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical patterns and processes,and highlight the integration of multiple disciplines.In this paper,we discussed the problems and challenges that landscape ecology is currently facing,emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes.We suggested that the focus should be on the integration of ground-based observation,mobile monitoring,transect survey,and remote-sensing monitoring,as well as improved coupling of experimental and model simulations.In addition,we outlined the research frontiers in landscape ecology,including scaling,integrated pattern and process modeling,and regional synthesis.Lastly,a brief review of pat-tern-process-scale coupling studies in China was provided.We concluded by pointing out that pattern-process-scale interactions,correlations between natural,economic,and social processes,and the coupling of human and natural systems will be major research areas in landscape ecology in the future.
基金This work was supported by the National Natural Science Foundation of China(Grant No.20272040).
文摘Cp2Yb·2THF reacts with CpNa in 1:1 molar ratio in THF at 40℃ for 2 h, and the in situ generated ani-onic divalent complex NaYbCp3(THF)n reacts further with an excess of CpH at 40℃ for 48 h, after work-up, affording the trivalent anionic ytterbium complex [Na(THF)2(μ2-η5-Cp) (η5,η5,η1-Cp3Yb)(THF)]n (1) by oxidation reaction of Cp2Yb with CpH. Crystal structure determination reveals that com-plex 1 has one-dimension polymeric chains of distinct Na(THF)2(μ2-η5-Cp)(η5,η5,η1-Cp3Yb)(THF) units, which were formed by the coordination of the bridging Cp ligand with Cp3Yb·THF and Na(THF)2 in η5,η5 mode via self-assembly.
基金supported partly by“973 Program”under Grant No.2014CB340701by the National Natural Science Foundation of China under Grant Nos.61625205,91418204 and 61625206+2 种基金by CDZ Project CAP(GZ 1023)by the CAS/SAFEA International Partnership Program for Creative Research Teamssupported partly by the National Natural Science Foundation of China under Grant Nos.11290141,11271034 and 61532019
文摘Hybrid systems are dynamical systems with interacting discrete computation and continuous physical processes, which have become more common, more indispensable, and more complicated in our modern life. Particularly, many of them are safety-critical, and therefore are required to meet a critical safety standard. Invariant generation plays a central role in the verification and synthesis of hybrid systems. In the previous work, the fourth author and his coauthors gave a necessary and sufficient condition for a semi-algebraic set being an invariant of a polynomial autonomous dynamical system, which gave a confirmative answer to the open problem. In addition, based on which a complete algorithm for generating all semi-algebraic invariants of a given polynomial autonomous hybrid system with the given shape was proposed. This paper considers how to extend their work to non-autonomous dynamical and hybrid systems. Non-autonomous dynamical and hybrid systems are with inputs, which are very common in practice; in contrast, autonomous ones are without inputs. Furthermore, the authors present a sound and complete algorithm to verify semi-algebraic invariants for non-autonomous polynomial hybrid systems. Based on which, the authors propose a sound and complete algorithm to generate all invariants with a pre-defined template.
