支持服务关联的组合服务选择方法研究

在面向服务的应用中，服务集成商通过选择已有服务并对这些服务进行组合，为其消费者提供增值（value—added）服务．然而，现有的组合服务选择模型中，各可选服务被认为是相互独立的，可选服务的服务质量独立于其他服务．而在实际的面向服务应用中，可选服务的服务质量往往依赖于其他可选服务，现有组合服务选择方法无法应对这种普遍存在的场景．文中提出了一个支持服务关联关系的QoS描述模型，用于刻画可选服务的服务质量对其他可选服务的依赖关系，并给出该QoS描述的自动生成方法．在此基础上，提出了支持服务关联的组合服务选择方法，包括基于整数规划求解最优解的组合服务选择方法和基于启发求解次优解的组合服务选择方法．通过实例分析，体现了文中方法具有良好的适用性．对比实验结果表明，文中基于整数规划方法获取的组合服务QoS明显优于同类方法；并且，文中基于启发式方法能够高效地获取较优组合服务QoS．

Influence of zinc phthalocyanines on photoelectrical properties of hydrogenated amorphous silicon

Composites consisting of hydrogenated amorphous silicon (a-Si: H, inorganic) and zinc phthalocyanine (ZnPc, organic) were prepared by vacuum evaporation of ZnPc and sequential deposition amorphous silicon via plasma enhanced chemical vapor deposition (PECVD). The optical and electrical properties of the composite film have been investigated. The results demonstrate that ZnPc can endure the temperature and bombardment of the PECVD plasma and photoconductivity of the composite film was improved by 89.9% compared to pure a-Si: H film. Electron mobility-lifetime products μτ of the composite film were increased by nearly one order of magnitude from 6.96 × 10~(-7) to 5.08 × 10~(-6) cm~2/V. Combined with photoconductivity spectra of the composites and pure a-Si: H, we tentatively elucidate the improvement in photoconductivity of the composite film.

不同长度β_2整合素_M亚基与ICAM-1的亲和性比较

<正>整合素作为细胞表面糖蛋白受体,介导细胞-细胞、细胞-胞外基质以及细胞-病原体间粘附和信息传递,在免疫应答、凝血反应、炎症反应、肿瘤转移和创伤愈合等许多病理生理过程中起重要作用。整合素是由α、β两个亚基非共价结合而成的异源二聚体,其结构类似于两条近平行的腿部支撑着一个球形的头部。研究表明,β_2整合素_M亚基头部的.domain为与配体直接作用的结构域,并可通过"open"或"close"的构象变化

新疆萨瓦亚尔顿（穆龙套型）金矿床物质来源与成矿机制

萨瓦亚尔顿金矿床是我国90年代金矿地质工作者在新疆西南天山地区寻找穆龙套型金矿床的一个突破。本文通过对新疆萨瓦亚尔顿金矿床的矿石矿物组成、稀土元素地球化学、同位素地球化学以及流体包裹体特征等方面的研究，探讨了萨瓦亚尔顿金矿床地质地球化学特征、金的赋存状态及成矿流体特征、成矿流体来源，提出了该矿床的成矿机制，取得如下认识：1．流体包裹体岩相学研究表明，萨瓦亚尔顿金矿床的流体包裹体主要为V＋L相和富CO_2相包裹体，前者为NaCl-H_2O体系，后者主要有L_(CO2)、L_(CO2)+L、V_(CO2)+L、V_(CO2)＋L_(CO2)＋L相包裹体；并发现极少量含子晶流体包裹体。2．通过流体包裹体显微测温学研究，表明金矿床的均一温度成矿早阶段为270～320 ℃，成矿主阶段为170～250 ℃，成矿晚阶段为110-250 ℃，呈逐渐降低的趋势，低温成矿作用明显。3．单个流体包裹体的激光拉曼分析表明，流体包裹体中除含有CO2之外，还含有一定量的N_2和CH_4。4.成矿物质来源的复杂性。萨瓦亚尔顿金矿床矿石中微量元素组成、稀土配分模式大都反映了成矿金属物质主要来自赋矿地层本身。金属硫化物的6345：-3.4‰～+2.6‰，西南天山地区下古生界地层中广泛存在各类火山岩可能是该矿床的主要硫源，部分可能有深部物质的参与。矿石中主要脉石矿物石英和菱铁矿 中包裹体水的氢氧同位素组成为δD = -72％～-62‰，δ~(18)O ＝ -11.6‰～＋5.4‰。成矿流体主要为大气降水补给的地下卤水，并有少量岩浆水的混合。5．Ar-Ar同位素地球化学研究表明，萨瓦亚尔顿金矿床的主要成矿时代为印支晚期，210 Ma。6. 对矿石中的流体包裹体进行了温度、压力、成分、pH、含盐度等的分要的，并系统的进行了矿床形成时的物理化学条件的理论计算，基中包括EH、PH、f_(O_2)、f_(S_2)等及金在矿液运移中的搬运形式。指出减压过程或伴生沸腾的减压过程，是矿床形成过程中矿质卸载的基本机制，此外，酸蚀变过程（如绢云母化等）中由于H~+的消耗促进了溶液中pH值的升高；含高炭质的围岩，降低了矿液的氧逸度以及含矿热液与地表下渗冷水的混合等诸多因素，则是矿订形成的辅助机制。

Coherent spectral enhancement of carrier-envelope-phase stable continua with dual-gas high harmonic generation

Attosecond science is enabled by the ability to convert femtosecond near-infrared laser light into coherent harmonics in the extreme ultraviolet spectral range. While attosecond sources have been utilized in experiments that have not demanded high intensities, substantially higher photon flux would provide a natural link to the next significant experimental breakthrough. Numerical simulations of dual-gas high harmonic generation indicate that the output in the cutoff spectral region can be selectively enhanced without disturbing the single-atom gating mechanism. Here, we summarize the results of these simulations and present first experimental findings to support these predictions. (c) 2012 Optical Society of America

A further investigation of the kinetic demixing/decomposition of La0.6Sr0.4Co0.2Fe0.8O3- δ oxygen separation membranes

Kinetic demixing and decomposition were studied on three La_0.6Sr_0.4Co_0.2Fe_0.8O_{3- δ} oxygen-separation hollow fibre membrane modules, which were operated under a 0.21/0.009bar oxygen partial pressure difference at 950°C for 1128, 3672 and 5512h, respectively. The post-operation membranes were characterized by Secondary Ion Mass Spectrometry, Scanning Electronic Microscope, Energy Dispersive Spectrum and X-ray Diffraction. The occurrence of kinetic demixing and decomposition was confirmed through the microstructural evolution of the membranes. Secondary-phase grains were found on the air-side surface of the membranes after the long-term operation and Co and Fe enrichment as well as La depletion was found on the surface and in the bulk at the air side. Cation diffusivities were found to be in the order Co>Fe>Sr>La. Kinetic demixing and decomposition rates of the membranes at the air side were found to be self-accelerating with time; the role of A-site deficiency in the perovskite lattice in the bulk near the air side surface is implicated in the mechanism. The oxygen permeability was not affected by the kinetic demixing and decomposition of the material during long-term operation (up to 5512h), however, we may expect permeability to be affected by secondary phase formation on the air-side surface at even longer operational times. © 2010 Elsevier B.V.

The development and optimization of a modified single-drop microextraction method for organochlorine pesticides determination by gas chromatography-tandem mass spectrometry

We have developed a new method for single-drop microextraction (SDME) for the preconcentration of organochlorine pesticides (OCP) from complex matrices. It is based on the use of a silicone ring at the tip of the syringe. A 5 μL drop of n-hexane is applied to an aqueous extract containing the OCP and found to be adequate to preconcentrate the OCPs prior to analysis by GC in combination with tandem mass spectrometry. Fourteen OCP were determined using this technique in combination with programmable temperature vaporization. It is shown to have many advantages over traditional split/splitless injection. The effects of kind of organic solvent, exposure time, agitation and organic drop volume were optimized. Relative recoveries range from 59 to 117 %, with repeatabilities of <15 % (coefficient of variation) were achieved. The limits of detection range from 0.002 to 0.150 μg kg−1. The method was applied to the preconcentration of OCPs in fresh strawberry, strawberry jam, and soil.

O impacto do desenvolvimento da consciência morfológica na escrita de crianças com e sem dislexia

Dissertação apresentada à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Educação Especial, ramo Multideficiência e Problemas de Cognição

L'Écho de Paris

1894/06/14 (Numéro 3672).

Resoluciones Cámara de Comercio de Bogotá

Doctrina