Flower-like CuO and flower-like CuO/graphene composite were prepared successfully by hydrothermal method. They were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, temperature-pr...Flower-like CuO and flower-like CuO/graphene composite were prepared successfully by hydrothermal method. They were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, temperature-programmed reduction, and thermogravimetric analysis. It is found that the flower-like CuO microspheres, which are composed of CuO nanosheets, possess an average diameter of 4.2 μm and a Brunauer–Emmett–Teller surface area of 12.6 m2/g. Compared with the flower-like CuO, the obtained flower-like CuO/graphene composite shows an enhanced electrochemical performance with a higher capacity of 603 mA-h/g at 0.1 C rate and 382 mA-h/g at 1 C rate, and exhibits a better cycle stability with a high capacity retention of 95.5 % after 50 cycles even though at 1 C rate.展开更多
P2P(Peer to Peer)系统的模型目前来说基本上分为纯分散式结构和服务器辅助式结构,这两种结构各有其优缺点。文中基于简单的模拟现实社会结构的思想和P2P系统需求的特殊性,结合WebService的技术优势,提出了一种基于HTTP和XML的区域式P2...P2P(Peer to Peer)系统的模型目前来说基本上分为纯分散式结构和服务器辅助式结构,这两种结构各有其优缺点。文中基于简单的模拟现实社会结构的思想和P2P系统需求的特殊性,结合WebService的技术优势,提出了一种基于HTTP和XML的区域式P2P系统模型并详细描述了系统运作的细节。该模型将资源搜索和文件传输统一在WebService上实现,并充分利用了分散于各节点上的计算能力,克服了纯分散式结构管理困难和难于发现其它节点的缺点以及服务器辅助式结构容易产生服务器瓶颈和服务器失效时系统瘫痪的缺点。展开更多
基金Project (20110490594) supported by China Postdoctoral Science Foundation
文摘Flower-like CuO and flower-like CuO/graphene composite were prepared successfully by hydrothermal method. They were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption, temperature-programmed reduction, and thermogravimetric analysis. It is found that the flower-like CuO microspheres, which are composed of CuO nanosheets, possess an average diameter of 4.2 μm and a Brunauer–Emmett–Teller surface area of 12.6 m2/g. Compared with the flower-like CuO, the obtained flower-like CuO/graphene composite shows an enhanced electrochemical performance with a higher capacity of 603 mA-h/g at 0.1 C rate and 382 mA-h/g at 1 C rate, and exhibits a better cycle stability with a high capacity retention of 95.5 % after 50 cycles even though at 1 C rate.
文摘P2P(Peer to Peer)系统的模型目前来说基本上分为纯分散式结构和服务器辅助式结构,这两种结构各有其优缺点。文中基于简单的模拟现实社会结构的思想和P2P系统需求的特殊性,结合WebService的技术优势,提出了一种基于HTTP和XML的区域式P2P系统模型并详细描述了系统运作的细节。该模型将资源搜索和文件传输统一在WebService上实现,并充分利用了分散于各节点上的计算能力,克服了纯分散式结构管理困难和难于发现其它节点的缺点以及服务器辅助式结构容易产生服务器瓶颈和服务器失效时系统瘫痪的缺点。
