Tuning of the periodicity of stable self-organized metallic templates

The atomic and electronic structures of Pb bilayer/Pt(111) are investigated with two theoretical calculations.We find that the stable (2 × 2)/(3 × 3) Pb/Pt(111) structure is a promising candidate for being used as a template with self-organized ordered Pb semi-cluster array on the first Pb monolayer.This stable structure can realize the ordered Au single-atom array around the Pb semi-clusters that can cause selective adsorption of noble atoms.The size of Pb magic number semi-cluster plays a more important role in determining the periodicity of the template than the lattice constant misfit between the substrate and the overlayer.This leads to quite a different periodicity between the two stable templates,which are (2 × 2)/(3 × 3) Pb/Pt(111) and Pb/Cu(111).Therefore,by considering the size of the stable semi-clusters and carefully selecting different substrate materials,we can tune the density of Pb semi-clusters as the nucleation points and then tune the periodicity of the stable template.     

Adaptive local routing strategy on a scale-free network

Due to the heterogeneity of the structure on a scale-free network, making the betweennesses of all nodes become homogeneous by reassigning the weights of nodes or edges is very difficult. In order to take advantage of the important effect of high degree nodes on the shortest path communication and preferentially deliver packets by them to increase the probability to destination, an adaptive local routing strategy on a scale-free network is proposed, in which the node adjusts the forwarding probability with the dynamical traffic load (packet queue length) and the degree distribution of neighbouring nodes. The critical queue length of a node is set to be proportional to its degree, and the node with high degree has a larger critical queue length to store and forward more packets. When the queue length of a high degree node is shorter than its critical queue length, it has a higher probability to forward packets. After higher degree nodes are saturated (whose queue lengths are longer than their critical queue lengths), more packets will be delivered by the lower degree nodes around them. The adaptive local routing strategy increases the probability of a packet finding its destination quickly, and improves the transmission capacity on the scale-free network by reducing routing hops. The simulation results show that the transmission capacity of the adaptive local routing strategy is larger than that of three previous local routing strategies.     

有机智能传感材料与器件研究进展

有机光电子材料具有柔性、低成本、可大面积加工以及分子结构可调等特点,在可穿戴智能器件领域具有巨大的应用潜力.有机分子可以通过结构的设计调节其光学、电学、机械和化学等特性,从而实现丰富的传感功能.有机智能传感器具有快速响应、高选择性、高灵敏和机械柔性等优势,被广泛应用于环境监测、电子皮肤、医疗监测、人机交互等智能感知领域.本文综述了近年来有机智能传感材料与器件的研究进展,包括小分子半导体、聚合物半导体和导电聚合物等有机传感材料,以及化学传感器、温度传感器、光学传感器和机械传感器等有机智能传感器件的前沿应用,重点介绍了目前生物传感器、仿生传感器等智能感知器件和系统的发展现状,并对其未来发展过程中面临的挑战进行了分析.