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991.
992.
首先,以高能物理领域数据处理为例,分析了支撑科学研究的大数据平台在存储和处理能力、传输和共享等方面的挑战,说明现有技术已经难以满足日益快速增长的数据处理需求。然后,给出了科研大数据平台的典型架构,并讨论科研大数据平台的关键技术,包括数据采集与清洗、数据存储、数据处理、数据传输、数据共享与安全等技术,同时介绍了各种关键技术的研究现状或者主流系统。最后,介绍了中国科学院高能物理研究所科研大数据开放平台的建设思路和实现框架,该平台试图解决目前大数据发展过程中面临的一些问题,如数据开放和跨领域融合不够、跨地域数据传输性能低等,从而激活数据价值,降低应用门槛。 相似文献
993.
循环荷载作用下钢结构滞回性能的数值模型 总被引:3,自引:0,他引:3
提出了“塑性铰有限分布”的数值模型用以分析钢结构在循环荷载作用下的滞回性能。经与试验结果比较表明模型简单、易于实施,待进一步完善后,可直接用于对梁及压弯构件的模拟。 相似文献
994.
Plastic flow and fracture of metallic glass 总被引:7,自引:0,他引:7
The tensile flow and fracture behavior of three Pdo.8Sio2-based alloys in the glassy, “microcrystalline,” and fully crystalline condition has been studied. The glassy alloys flow
plastically to a total strain of approximately 0.5 pct e, and exhibit proportional limit stresses of approximatelyE x 10~2 whereE is Young’s modulus. This plastic flow is accompanied by the formation of shear deformation bands on the specimen surfaces.
Fully crystalline alloys are extremely brittle and fracture via intergranular cracking. Fracture surfaces of the amorphous
and “microcrystalline” alloys are inclined at 45 deg to the tensile axis and exhibit two morphologically distinct zones. One
zone is relatively featureless while the other contains a “river” pattern of local necking protrusions. Detailed comparison
of opposing surfaces indicates that fracture is preceded by large local plastic shear which produces the smooth zone while
the local necking pattern is produced during rupture. These observations form the basis for the hypothesis that plastic flow
in the glassy material occurs via localized strain concentrations and that fracture is initiated by catastrophic, “adiabatic”
shear.
Formerly Postdoctoral Associate, Yeshiva University, New York, N. Y. 相似文献
995.
The influences of vegetation on intraseasonal oscillation (ISO) were examined using the Community Atmosphere Model version 3 (CAM3). Two 15-year numerical experiments were completed: the first was performed with a realistic vegetation distribution (VEG run),and the second was identical to the VEG run except without land vegetation (NOVEG run). Generally speaking, CAM3 was able to reproduce the spatial distribution of the ISO, but the ISO intensity in the simulation was much weaker than that observed in nature: the ISO has a relatively much stronger signal. A comparison of the VEG run with the NOVEG run revealed that the presence of vegetation usually produces a weak ISO. The vegetation effects on ISO intensity were significant over West Africa and South Asia, especially in the summer half-year.Vegetation also plays an important role in modulating ISO propagation. The eastward propagation of the ISO in the VEG run was clearer than that in the NOVEG run over the West African and Maritime Continent regions. The northward propagation of the ISO in the VEG run was more consistent with observation than that in the NOVEG run. 相似文献
996.
997.
998.
知识经济是当前人们讨论的热门话题之一。对知识经济时代到来及由此产生的深刻变化应有充分的准备。作者就知识经济的意义及如何发展知识表明几点看法。 相似文献
999.
Photocatalysts with perovskites for hydrogen production from aqueous solution were reviewed. Among the most of metal oxide photocatalysts, the family of ABO3 Perovskite-type oxide shows higher photocatalytie activity, especially alkaline earth titanate and alkali tantalate. Therein, sodium tantalate showed the highest activity for water splitting. The reasons for the high photocatalytic activity of ABO3 perovskties are considered to the diverse and flexible crystal structure. The photocatalytic activity of ABO3 perovskties can be improved by doping other element at A site, B site or O site and loading CO-catalysts such as NiO and Pt. In this paper, the mechanism of photocatalytic water splitting, the structure of ABO3 perovsktie, and Perovskite-type photocatalysts were reviewed. 相似文献
1000.