310 resultados para secante Cesena, lotto 0 Cesena
Resumo:
门户(Portal)是基于组件的web应用,它可以集成Internet环境下各种现有应用系统、数据资源和网络信息资源,并为用户形成个性化的访问页面,实现信息的集成和发布。Portlet是门户中的可重用组件,能够提供对web内容、应用程序和其他资源的访问。JSR168规范(Portlet 1.0)和JSR286规范(Portlet 2.0)提供了Portlet的标准。 随着门户的广泛使用,门户已经成为获取信息,巩固和整合IT基础设施的平台。于是来自于同一公司的、自主的、分散的多个部门都部署了自己的门户,但这些门户之间却无法进行内容共享,即Portlet在门户之间的集成。于是出现了联邦门户(Federated Portals),它是由多个分散的门户构成的网络,这些门户基于共同的标准协同工作。联邦门户实现了在异构门户之间共享远程内容,这些远程内容来自于名为生产者的门户,被收集、组合和运行在名为消费者的门户中。 联邦门户的基本特征是基于规范实现跨门户的系统联合。因此联邦门户的关键在于对门户间互操作标准的制定。这个标准就是OASIS推出的WSRP(Web Services for Remote Portlets)规范。WSRP规范提供了门户间互操作标准,成为联邦门户的基础技术。它有1.0和2.0两个版本,分别产生于2003年和2008年。 为了提高联邦门户应用的构建效率,增强异构门户互操作性的能力,完善联邦门户的用户友好性,需要为OncePortal提供支持WSRP 2.0规范的联邦门户。 本文从WSRP 2.0规范和联邦门户的需求出发,设计并实现了支持WSRP 2.0规范的联邦门户。首先根据WSRP 2.0规范对远程Portlet的语法模型、交互模型和生命周期模型三个方面进行特征分析;其次总结了联邦门户的核心功能、系统边界,并给出了联邦门户的设计;然后从Portlet URL的生成与改写、Portlet统一协作框架、远程Portlet资源服务、WSRP容器和代理容器以及Portlet缓存共5个方面介绍了联邦门户的关键技术;最后基于以上分析和设计,实现了联邦门户扩展应用,并将其应用在中科院软件所自主研发的门户产品OncePortal中。
Resumo:
Results are reported of electric-field dependence on thermal emission of electrons from the 0.40 eV level at various temperatures in InGaP by means of deep-level transient spectroscopy. The data are analyzed according to the Poole-Frankel emission from the potentials which are assumed to be Coulombic, square well, and Gaussian, respectively. The emission mte from this level is strongly field dependent. It is found that the Gaussian potential model is more reasonable to describe the phosphorus-vacancy-induced potential in InGaP than the Coulombic and square-well ones.
Resumo:
采用金属有机物化学气相淀积(MOCVD)技术,在蓝宝石衬底上生长了Al_(0.48)Gao_(0.52)N/Al_(0.54)Ga_(0.36)N多量子阱(MQWs)结构.通过双晶X射线衍射(DCXRD)、原子力显微镜(AFM)和阴极荧光(CL)等测试技术,分别对样品的结构和光学特性进行了表征.在DCXRD图谱中,可以观察到明显的MQWs衍射卫星峰,通过拟和,MQWs结构中阱和垒的厚度分别为2.1和9.4 nm,Al组分分别为0.48和0.54.在AFM表面形貌图上,可以观察到清晰的台阶流,表明MQWs获得了二维生长;与此同时,MQWs结构存在一些裂缝,主要原因为AlGaNMQWs结构和下层GaN层间存在很大的应力.CL测试表明,AlGaN MQWs结构的发光波长为295 nm,处于深紫外波段,同时观察到处于蓝光、绿光波段的缺陷发光.
Resumo:
A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency (PCE). The internal quantum efficiency, the series resistance, and the thermal resistance were theoretically optimized. The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers. The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs_0.9P_0.1/InGaAs quantum well. Experimentally, a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink, and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE.
Resumo:
由于Si/SiGe异质结构的带阶差主要发生在价带,为实现高效率的发光,本文从理论上设计了在硅基Si_(1-x) Ge_x虚衬底上外延应变补偿的Si/S_(1-y) Ge_y(y>x)量子阱的能带结构,将量子阱对电子的限制势垒提高到100meV以上.在实验上,采用300℃生长的Ge量子点插入层,制备出薄的SiGe驰豫缓冲层(虚衬底),表面Ge组份达到0.25,表面粗糙度小于2nm,驰豫度接近100%.在我们制备的SiGe缓冲层上外延了应变补偿SiGe/Si多量子阱结构,并初步研究了其发光特性.
Resumo:
在低温强磁场条件下,对In_(0.53)Ga_(0.47)As/In_(0.52)Al_(0.48)As量子阱中的二维电子气进行了磁输运测试.在低磁场范围内观察到正磁电阻效应,在高磁场下这一正磁电阻趋于饱和,分析表明这一现象与二维电子气中的电子占据两个子带有关.在考虑了两个子带之间的散射效应后,通过分析低磁场下的正磁电阻,得到了每个子带电子的迁移率,结果表明第二子带电子的迁移率高于第一子带电子的迁移率.进一步分析表明,这主要是由两个子带之间的散射引起的.
Resumo:
Lattice matched Ga_(1-x)In_xAs_ySb_(1-y) quaternary alloy films for thermophotovoltaic cells were successfully grown on n-type GaSb substrates by liquid phase epitaxy. Mirror-like surfaces for the epitaxial layers were achieved and evaluated by atomic force microscopy. The composition of the Ga_(1-x)In_xAs_ySb_(1-y) layer was characterized by energy dispersive X-ray analysis with the result that x = 0.2, y = 0.17. The absorption edges of the Ga_(1-x)In_xAs_ySb_(1-y) films were determined to be 2. 256μm at room temperature by Fourier transform infrared transmission spectrum analysis, corresponding to an energy gap of 0.55eV. Hall measurements show that the highest obtained electron mobility in the undoped p-type samples is 512cm2~/(V·s) and the carrier density is 6. 1×10~(16)cm~(-3) at room temperature. Finally, GaInAsSb based thermophotovoltaic cells in different structures with quantum efficiency values of around 60% were fabricated and the spectrum response characteristics of the cells are discussed.