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61.
海底油气集输管网可靠性评估 总被引:1,自引:0,他引:1
对海底油气集输管网进行了可靠性评估,提出了一种适用于树状海底油气集输管网可靠性评价的方法,将流可靠度和单元重要度的概念引入到海底油气集输管网可靠性的分析中,该方法能够有效地评价海底油气集输管网的可靠性。 相似文献
62.
在综合的科学考察船上以异步通讯口实现的IBM-PC局部网具有较好的性能价格比。本文介绍了该网的联网环境、网络系统的组成及其拓扑结构、网络的服务功能以及网络软、硬件的安装和配置。 相似文献
63.
可靠性约束下的海底油气集输管网系统优化 总被引:1,自引:0,他引:1
在管网系统满足一定可靠度的基础上,以费用最小为优化目标,对系统进行了优化,求出了满足一定可靠度指标的费用最小的管网布置方案。对树状网络可靠性进行了评估,提出了一个0-l规划模型,并运用图论和网络理论将管网系统的优化问题转变为求可靠度至少为α的网络固的最小生成树问题。 相似文献
64.
65.
船舶机舱自动集中监测报警系统结构与功能分析 总被引:1,自引:0,他引:1
船舶机舱集中监测与报警系统目前已在船舶设计制造中得以广泛应用。对其组成、工作流程及功能进行了较为系统的阐述 ,为船舶使用者提供借鉴 相似文献
66.
水下自航式海洋观测平台技术发展研究 总被引:3,自引:2,他引:3
水下自航式海洋观测平台是一种新型海洋观测平台,主要用于无人、大范围、长时间水下环境监测,包括物理学参数、海洋地质学和地球物理学参数,海洋化学参数、海洋生物学参数及海洋工程方面的现场接近观测。其特点是:成本低,环境适应性强,可冲破人工潜水极限而进入现场进行接近观测,免除了ROV需要水面支援母船的累赘,减少作业经费,体积小,使用方便,便于布放回收;可根据水声信号摇控或预置程序控制,按要求进行相关项目观测;有自主动力,水下运行时间相对较长,有源噪声低,可进行隐弊观测,正是基于以上的优点,近几年颇得海洋环境监测和海军方面的青睐,本文介绍了国际上水下自动观测平台的发展历史和现状,提出了我国开展研究水下自动观测平台的重要性及研究的面容。 相似文献
67.
A novel method for prediction of the load carrying capacity of a corroded reinforced concrete beam (CRCB) is presented in the paper. Nine reinforced concrete beams, which had been working in an aggressive environment for more than 10 years, were tested in the laboratory. Comprehensive tests, including flexural test, strength test for corroded concrete and rusty rebar, and pullout test for bond strength between concrete and rebar, were condueted. The flexural test results of CRCBs reveal that the distribution of surface cracks on the beams shows a fractal behavior. The relationship between the fractal dimensions and mechanical properties of CRCBs is then studied. A prediction model based on artificial neural network (ANN) is established by the use of the fractal dimension as the corrosion index, together with the basic intbrmation of the beam. The validity of the prediction model is demonstrated through the experimental data, and satisfactory resuits are achieved. 相似文献
68.
69.
The accuracy of the manufacturer’s fall-rate equation for the T-5 Model of expendable bathythermograph (XBT) has been investigated based on about 300 collocated pairs of XBT-CTD (Conductivity-Temperature-Depth profiler) measurements in various climatological regions. We found that the equation systematically overestimates depth by about 5% for the T-5 produced by Tsurumi Seiki, Co. Ltd. (TSK), but almost no bias is associated with the T-5 produced by Sippican, Inc., in USA. The cause of this difference is not clear, because the two manufacturers’ T-5 probes are reported to have identical shape and weight in water. We propose a new fall-rate equation for the TSK T-5: z(t) = 6.54071t - 0.0018691t
2, where z(t) is depth in meters at time, t, in seconds. 相似文献
70.
Anna Badosa Dani Boix Sandra Brucet Rocío Lpez-Flores Xavier D. Quintana 《Estuarine, Coastal and Shelf Science》2006,66(3-4):513-522
The role of the hydrological regime in the nutrients and zooplankton composition and dynamics has been analysed in five lagoons of La Pletera salt marshes (NE Iberian Peninsula) during a complete hydrological cycle (2002–2003). Two of the lagoons have their origin in the old river mouths while the other three were recently created in the framework of a Life Restoration project. This fact has also allowed us to study the effect of the lagoon age on nutrient and zooplankton composition and dynamics. The salt marsh hydrology is determined by a prolonged period of confinement without water inputs, irregularly interrupted by sudden water inputs due to flooding events (sea storms or intense rainfalls). While the dynamics of oxidized nitrogen compounds in the lagoons depends on the water inputs variability within each hydrological cycle, the internal load of phosphorus, total nitrogen and organic matter is related more to the cumulative mechanisms during the confinement periods. Accumulation processes may be easily related to lagoon age, since old lagoons have higher content of nutrients and organic matter, suggesting that these lagoons progressively accumulate nutrients during the successive confinement events. This is the usual case for most Mediterranean salt marshes without an artificially manipulated water regime. The zooplankton community in La Pletera integrates the effects of both the hydrological regime and the lagoon age since the former determines the temporal pattern of the main zooplankton species and the latter explains differences in composition and structure between old and new lagoons. 相似文献