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排序方式: 共有250条查询结果,搜索用时 31 毫秒
1.
滇西南中生代盐盆地钾盐资源调查评价项目MK-3井,设计井深2700 m,全孔取心,岩心直径≮80 mm,一般井段岩心采取率达到80%以上,盐岩段岩心采取率>95%。工程技术要求高,施工难度大。施工中遇到了地层坍塌、涌水、掉块、盐岩溶蚀等问题,通过采用氯化镁饱和盐水冲洗液,HXY-9B型钻机取心钻进、TSJ-2000型水源钻机扩孔钻进,分级下管隔离等措施,圆满完成了钻探任务。完钻井深2701 m,岩心采取率90%,盐岩段岩心采取率达98.65%,终孔口径127 mm,岩心直径81 mm。经地球物理测井,各项指标都达到了设计要求。刷新了国内CHD127标准绳索取心钻杆P口径钻探深度的记录。 相似文献
2.
Retaining wall optimization using interior search algorithm with different bound constraint handling 下载免费PDF全文
Along with the applicability of optimization algorithms, there are lots of features that can affect the functioning of the optimization techniques. The main purpose of this paper is investigating the significance of boundary constraint handling (BCH) schemes on the performance of optimization algorithms. To this end, numbers of deterministic and probabilistic BCH approaches are applied to one of the most recent proposed optimization techniques, named interior search algorithm (ISA). Apart from the implementing different BCH methods, a sensitivity analysis is conducted to find an appropriate setting for the only parameter of ISA. Concrete cantilever retaining wall design as one of the most important geotechnical problems is tackled to declare proficiency of the ISA algorithm, on the one hand, and benchmark the effect of BCH schemes on the final results, on the contrary. As results demonstrate, various BCH approaches have a perceptible impact on the algorithm performance. In like manner, the essential parameter of ISA can also play a pivotal role in this algorithm's efficiency. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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《Geoforum》2015
Over the last decade, fire governance practices in the British Fire and Rescue Service (FRS) have undergone fundamental transformation. Rather than just being responded to as and when they occur, the FRS have adopted a range of anticipatory governing strategies to govern fires in anticipation of their occurence. This turn towards anticipatory governance has been facilitated in no small part by the digital infrastructure now embedded in the FRS. Composed of data, hardware, software, fibre-optic cables along with human analysts and organisational processes, this infrastructure operates to make risk projections on fire which shape and condition strategic decision making. This paper explores the operation of this digital infrastructure through the notion of interface. Drawing on empirical material relating to processes of data sourcing and risk calculation, interfaces account for the sites, moments and experiences in which human and non-human agents relate to one another in making fire risk projections. Showing relations to exist spatially, temporally and sensually, I argue that interfaces are crucial to the operation of an anticipatory security apparatus which relies on digital devices. 相似文献
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Social models of population vulnerability to disasters increasingly include the notion that vulnerability has a strong temporal component. While this temporality is typically conceptualized as objective (making vulnerability “dynamic,” “multiscalar,” and/or “historical”), it consistently fails to acknowledge that among stakeholders managing hazardscapes temporality is also a social process in which subjective experience of time may play a role in creating situations of population vulnerability. This paper proposes that the temporal situatedness of a population relative to past hazard events and the quality with which stakeholders engage hazard memory-chains combine to significantly influences its vulnerability to natural hazards. It is proposed that this temporal vulnerability is characterized by shared, population level potential for surprise and can be evaluated by exploration of time-series depth and temporal reference points in historical ecological narratives and documents. Based on ethnohistoric research conducted from 2002 to 2006 in flood-prone eastern North Carolina (USA), it is illustrated how temporal vulnerability was relatively higher in the Neuse River watershed located at the City of Kinston than surrounding watersheds. Due to the combination of factors including the damming of the Neuse River in the 1980s, outdated official floodplain maps, relatively unmonitored floodplain development, the stochastic timing of flood events (placing the last major flood more than a generation away), technological optimism, and turnover of floodplain officials and residents, local stakeholders were seriously misinformed about the space-time risks involved both before and after the disaster of Hurricane Floyd (1999) happened. To deal with this inconsistency, the temporal rarity of Hurricane Floyd as a “500-year event” has been motivated and embraced by many in an effort to continue life-as-is. The paper proposes that the concept of temporal vulnerability is further explored and used as key dimension in the vulnerability sciences. 相似文献
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Geographic information system (GIS) based methodologies are widely used to various problems. However, its potential for application to strategic maritime search and rescue (SAR) planning remains largely unexplored. To investigate the applicability of GIS-based tools to this problem, this paper presents an approach to evaluate accessibility and response times in a sea area. Such information aids to objectify the response effectiveness of a SAR system, which is important for rational resource allocation. The presented methodology accounts for the main characteristics of maritime response, namely spatial accessibility, capabilities of search and rescue units (SRUs) and prevailing wave conditions, which affect the attainable SRU speeds. An application to the Finnish areas of the Gulf of Finland is shown. Despite the existence of some difficulties with currently available tools (e.g. accurate and user-friendly spatial wave models and challenges with using raster-based methods in topologically complex areas) and limitations in knowledge (e.g. the SRU capabilities in actual operations), the results indicate that the methodology provides good opportunities for enhancing maritime decision making. 相似文献
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Ana C. Silva Ana C. Amador Sónia Brazão Claúdia Faria Diana Boaventura 《Marine Ecology》2010,31(4):525-532
Patellid limpets are key species on rocky shores, structuring intertidal assemblages through their grazing. Their role as prey for fish is, however, often overlooked in studies of intertidal ecosystem functioning. The shanny Lipophrys pholis is a common predator of limpets on rocky shores in Northern Europe and, in this study, we examined the characteristics of its predation on limpets based on prey size. The limpet size range that adult L. pholis (10–12.5 cm) can eat was examined in the laboratory using Patella depressa in 0.2 cm classes, varying between 0.5 cm and 3.0 cm in maximum shell length. There was a limpet size refuge above 1.8 cm, while all smaller sizes were readily consumed by the shanny. The predator attacking behaviour was also examined and found to vary with prey size. Limpets up to 0.8 cm were crushed by the jaw‐constricting force and eaten whole, whereas larger prey were prised from the substratum and the body subsequently separated from the shell. To examine whether there was a L. pholis preference for P. depressa size, a two‐stage laboratory experiment was done using two size classes defined as small (0.7–0.8 cm maximum shell length) and large (1.5–1.6 cm maximum shell length). In the first stage, the predator was given each limpet size class separately. In the second stage, the fish was given a choice between the two classes. Lipophrys pholis was shown to have a preference for the large size class (1.5–1.6 cm). The average number of limpets consumed by the shanny was examined for the duration of one high‐tide typical of the central region of Portugal (≈ 4 h). On average, approximately five limpets (up to an eight limpet maximum) were consumed. The present study shows that L. pholis has a feeding preference based on limpet size, which suggests that the limpet population structure and intra‐ and inter‐specific interactions may be influenced by the shanny predation. 相似文献
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基于ArcGIS Server的地震应急数据与服务共享研究 总被引:1,自引:0,他引:1
ArcGIS Server是基于Web Service用来发布企业级GIS应用程序的综合平台。 本文以地震应急数据与服务共享为研究目标, 分析了ArcGIS Server的体系架构和几种常用共享模式的特点, 提出了基于Web Service和ArcGIS Server的共享模式, 详细阐述了地震应急数据与服务共享的理论方法和系统架构, 实现了基于ArcGIS Server开发地震应急信息共享的原型系统。 相似文献
10.
Jian Hua Li Zheng Ping Zhang Rui Huan Jing Chong Fu Huang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(4):485-492
In this paper, we introduce a value chain approach, on the view of the value chain analytic in business management, to be
the framework of a crisis response system serving for crisis management strategy in identifying risk sources, responding to
unexpected events, and recovering from a shock. This system is not only a computer system but also a system of governmental
emergency response mechanism and it is tremendous and complex. The system integrates and coordinates the correlative resources
of emergency response units of the city. We consider the efficiency of the system. In addition, the run cost of the system
also is taken into account. Based on this framework, the Qingdao’s practical situation is analyzed. As a result, a design
proposal of the Qingdao’s crisis response system is put forward. 相似文献