4 resultados para Roa, Armando
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
The three-dimensional morphology of In(Ga)As nanostructures embedded in a GaAs matrix is investigated by combining atomic force microscopy and removal of the GaAs cap layer by selective wet etching. This method is used to investigate how the morphology of In(Ga)As quantum dots changes upon GaAs capping and subsequent in situ etching with AsBr3. A wave function calculation based on the experimentally determined morphologies suggests that quantum dots transform into quantum rings during in situ etching. (c) 2007 American Institute of Physics.
Resumo:
Tunable biaxial stresses, both tensile and compressive, are applied to a single layer graphene by utilizing piezoelectric actuators. The Gruneisen parameters for the phonons responsible for the D, G, 2D and 2D' peaks are studied. The results show that the D peak is composed of two peaks, unambiguously revealing that the 2D peak frequency (omega(2D)) is not exactly twice that of the D peak (omega(D)). This finding is confirmed by varying the biaxial strain of the graphene, from which we observe that the shift of omega(2D)/2 and omega(D) are different. The employed technique allows a detailed study of the interplay between the graphene geometrical structures and its electronic properties.
Resumo:
海洋环境通常是不确定、非结构化和未知的 ,而远程AUV(LAUV)的避障声纳对环境感知有一定的局限 ,因此很难建立起精确、完整和统一的三维环境模型 .LAUV实时避障是一个实时性很强的动态过程 ,它不但与环境有关 ,而且还与LAUV的运动学约束、动力学特性和操纵性有关 .针对上述问题本文提出了一种基于复合控制的三维实时模糊避障方法
Resumo:
多数据源互操作与开放分布处理系统CIMS-MIODP是采用分布对象互操作与代理技术,实现面向CIMS的基于RPC的远程对象访问ROA(RemoteObjectAces)功能和基于SQL3的远程数据库访问RDA(RemotDatabaseAces)功能的系统,为CIMS环境下的信息集成与分布处理提供了不同层次的支持功能。本文讨论了CIMS-MIODP系统的主要设计和实现问题,包括基本模型、扩展服务和协议、对SQL3的支持、系统实现结构等。