With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and th...With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and the reduced thermal conductance for each region sensitively depend on geometric parameters, and are of quantum character, but the reduced total thermal conductance for all regions seems independent of structure parameters when the temperature is not very low. Our results show that one can control the thermal conductivity for each region to match practical requirements in devices by adjusting the geometric parameters.展开更多
Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magneti...Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magnetic flux the conductances for the two channels present remarkable difference from each other. When the quantum dots are made of ferromagnetic materials, the levels of quantum dots are spin dependent, then spin polarization comes about in the two channels. Furthermore, in some regions spin polarization in the different channels are opposite. We consider that this model can be a device prototype for spin filtering and spin separation.展开更多
Communication bandwidth and network topology are two important factors that affect performance of distributed consensus in multi-agent systems.The available works about quantized average consensus assume that the adja...Communication bandwidth and network topology are two important factors that affect performance of distributed consensus in multi-agent systems.The available works about quantized average consensus assume that the adjacency matrices associated with the digraphs are doubly stochastic,which amounts to that the digital networks are balanced.However,this assumption may be unrealistic in practice.In this paper,without assuming double stochasticity,the authors revisit an existing quantized average consensus protocol with the logarithmic quantization scheme,and investigate the quantized consensus problem in general directed digital networks that are strongly connected but not necessarily balanced.The authors first derive an achievable upper bound of the quantization precision parameter to design suitable logarithmic quantizer,and this bound explicitly depends on network topology.Subsequently,by means of the matrix transformation and the Lyapunov techniques,the authors provide a testable condition under which the weighted average consensus can be achieved with the proposed quantized protocol.展开更多
Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and c...Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and characterization of the imido, oxo, sulfido, and carbene-containing complexes of thorium. Such thorium complexes are of interest because of their unique structural properties, their potential application in novel group transfer reactions and catalysis, as well as their ability to engage the 5f orbitals in metal-ligand bonding. This short review summarizes the synthesis and reactivity of these thorium complexes.展开更多
基金The project supported by the Natural Science Foundation of Hubei Province of China under Grant No. 2003ABA004
文摘With the help of scattering-matrix method, the acoustic phonon ballistic transmission and the thermal conductivity are studied detailedly in a four-terminal structure. We find that the transmission coefficients and the reduced thermal conductance for each region sensitively depend on geometric parameters, and are of quantum character, but the reduced total thermal conductance for all regions seems independent of structure parameters when the temperature is not very low. Our results show that one can control the thermal conductivity for each region to match practical requirements in devices by adjusting the geometric parameters.
文摘Electron transport through a triple-terminal double-quantum-dot structure is theoretically studied. By adjusting the chemical potential in leads, two channels in this system are created, and in the presence of magnetic flux the conductances for the two channels present remarkable difference from each other. When the quantum dots are made of ferromagnetic materials, the levels of quantum dots are spin dependent, then spin polarization comes about in the two channels. Furthermore, in some regions spin polarization in the different channels are opposite. We consider that this model can be a device prototype for spin filtering and spin separation.
基金supported by the Major State Basic Research Development Program of China(973 Program)under Grant No.2010CB731400the Natural Science Foundation of China under Grant Nos.61074125,61073102,61170059,61170172,61272153Anhui Provincial Natural Science Foundation under Grant No.090412251
文摘Communication bandwidth and network topology are two important factors that affect performance of distributed consensus in multi-agent systems.The available works about quantized average consensus assume that the adjacency matrices associated with the digraphs are doubly stochastic,which amounts to that the digital networks are balanced.However,this assumption may be unrealistic in practice.In this paper,without assuming double stochasticity,the authors revisit an existing quantized average consensus protocol with the logarithmic quantization scheme,and investigate the quantized consensus problem in general directed digital networks that are strongly connected but not necessarily balanced.The authors first derive an achievable upper bound of the quantization precision parameter to design suitable logarithmic quantizer,and this bound explicitly depends on network topology.Subsequently,by means of the matrix transformation and the Lyapunov techniques,the authors provide a testable condition under which the weighted average consensus can be achieved with the proposed quantized protocol.
基金supported by the National Natural Science Foundation of China(21172022)the Program for New Century Excellent Talents in University(NCET-10-0253)Beijing Municipal Commission of Education
文摘Organoactinide complexes containing terminal metal-ligand multiple bonds have received widespread attention over the past three decades. In the last few years, significant progress has been made in the synthesis and characterization of the imido, oxo, sulfido, and carbene-containing complexes of thorium. Such thorium complexes are of interest because of their unique structural properties, their potential application in novel group transfer reactions and catalysis, as well as their ability to engage the 5f orbitals in metal-ligand bonding. This short review summarizes the synthesis and reactivity of these thorium complexes.
