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排序方式: 共有132条查询结果,搜索用时 15 毫秒
1.
Nathan M. Wilbur Antin M. O'Sullivan Kerry T. B. MacQuarrie Tommi Linnansaari R. Allen Curry 《河流研究与利用》2020,36(5):769-783
Anthropogenic influences, including climate change, are increasing river temperatures in northern and temperate regions and threatening the thermal habitats of native salmonids. When river temperatures exceed the tolerance levels of brook trout and Atlantic salmon, individuals exhibit behavioural thermoregulation by seeking out cold‐water refugia – often created by tributaries and groundwater discharge. Thermal infrared (TIR) imagery was used to map cold‐water anomalies along a 53 km reach of the Cains River, New Brunswick. Trout and salmon parr did not use all identified thermal anomalies as refugia during higher river temperature periods (>21°C). Most small‐bodied trout (8–30 cm) were observed in 80% of the thermal anomalies sampled. Large‐bodied trout (>35 cm) required a more specific set of physical habitat conditions for suitable refugia, that is, 100% of observed large trout used 30% of the anomalies sampled and required water depths >65 cm within or adjacent to the anomaly. Densities of trout were significantly higher within anomalies compared with areas of ambient river temperature. Salmon parr were less aligned with thermal anomalies at the observed temperatures, that is, 59% were found in 65% of the sampled anomalies; and densities were not significantly different within/ outside anomalies. Salmon parr appeared to aggregate at 27°C, and after several events over 27°C variability in aggregation behaviour was observed – some fish aggregated at 25°C, others did not. We stipulate this is due to variances of thermal fatigue. Habitat suitability curves were developed for velocity, temperature, depth, substrate, and deep water availability to characterize conditions preferred by fish during high‐temperature events. These findings are useful for managers as our climate warms, and can potentially be used as a tool to help conserve and enhance thermal refugia for brook trout and Atlantic salmon in similar systems. 相似文献
2.
The use of light gauge steel framing is increasing rapidly. New methods for joining frames are being sought. One of the most promising methods is clinching. Clinching has been used for almost 20 years. There has been much research into the method, the tools, suitable materials and applications. Few articles have been published concerning clinching of high strength structural steels, which are currently the most relevant materials for house construction.This study included 11 different clinching methods. In total, 469 test pieces were produced. Despite the high strength of the materials, all the clinching methods that were examined could be used satisfactorily. The most significant result was that a round tool is appropriate for all the materials tested. In fact, in comparison with results obtained using other types of tool, when the methods were ranked by maximum shear load capacity, the round design appeared in the top three classes seven times out of nine. 相似文献
3.
J. Varis R. Lehtiniemi J. Hartikainen J. Rantala 《Research in Nondestructive Evaluation》1994,6(2):85-97
Transportable equipment for on-site thermal nondestructive testing is described. The equipment is constructed from two separate
units: a hand-held infrared line scanner and a remote unit containing all the necessary control devices. The sample surface
is heated by manually scanning a line source over the surface and the resulting surface temperature rise is simultaneously
measured with the line scanner. The heating line is generated either by a line-focused laser beam or by a radio frequency
induction coil. The obtained surface temperature distribution of the monitored area is presented as a pseudo-color image.
The feasibility of the method is demonstrated with a carbon-glass fiber composite sample. 相似文献
4.
Cortajarena AL Kajander T Pan W Cocco MJ Regan L 《Protein engineering, design & selection : PEDS》2004,17(4):399-409
Protein design aims to understand the fundamentals of protein structure by creating novel proteins with pre-specified folds. An equally important goal is to understand protein function by creating novel proteins with pre-specified activities. Here we describe the design and characterization of a tetratricopeptide (TPR) protein, which binds to the C-terminal peptide of the eukaryotic chaperone Hsp90. The design emphasizes the importance of both direct, short-range protein-peptide interactions and of long-range electrostatic optimization. We demonstrate that the designed protein binds specifically to the desired peptide and discriminates between it and the similar C-terminal peptide of Hsp70. 相似文献
5.
Aspect-oriented software testing is emerging as an important alternative to conventional procedural and object-oriented testing techniques. This paper reports experiences from two case studies where aspects were used for the testing of embedded software in the context of an industrial application. In the first study, we used code-level aspects for testing non-functional properties. The methodology we used for deriving test aspect code was based on translating high-level requirements into test objectives, which were then implemented using test aspects in AspectC++. In the second study, we used high-level visual scenario-based models for the test specification, test generation, and aspect-based test execution. To specify scenario-based tests, we used a UML2-compliant variant of live sequence charts. To automatically generate test code from the models, a modified version of the S2A Compiler, outputting AspectC++ code, was used. Finally, to examine the results of the tests, we used the Tracer, a prototype tool for model-based trace visualization and exploration. The results of the two case studies show that aspects offer benefits over conventional techniques in the context of testing embedded software; these benefits are discussed in detail. Finally, towards the end of the paper, we also discuss the lessons learned, including the technological and other barriers to the future successful use of aspects in the testing of embedded software in industry. 相似文献
6.
Olli Varis 《国际水》2013,38(4):624-637
Abstract The Nile brings virtually no water to the sea. The mighty basin with 1/10 of Africa's land area and 1/3 of its population, has only 1/16 of its water. The riparian countries use practically all of the Nile's water and they face increasing challenges in terms of environmental degradation, food security, and socioeconomic development. The geopolitical situation blocks the integrated development of water resources in the basin scale, yet the political environment may be improving. The Nile basin is among the most critical regions of the world in terms of water resources development. In this article, the trends of the major driving forces within the basin countries—population, urbanization, climate, agriculture, economy, human resources, and governance—are scrutinized from the viewpoint of their impacts on water resources and their management. A comparison is made to four other critical macroregions: China, South Asia, Southeast Asia, and West Africa. 相似文献
7.
针对长江流域目前面临的诸多挑战,结合对第四届长江论坛关注点的回顾,总结了以长江流域发展为重点的研究成果,分析了沿江各省(区、市)的关注点与需求以及中国水资源政策与国际通用政策之间的异同,从而得出中国水资源政策应趋向国际通用政策及欧盟《水框架指令》的结论。 相似文献
8.
The animation environment Jeliot automates visualization of algorithms over the Internet. The user can visualize algorithms of his own, not merely the selection supplied by a service provider. Jeliot is based on self-animating data types: the user selects the data objects of the source code to be visualized, and Jeliot produces the animation based on operations performed on those types. We present the design of Jeliot and the principles of its implementation. In addition, we discuss the educational applications of Jeliot. 相似文献
9.
Valentina V Zhurikhina Pavel N Brunkov Vladimir G Melehin Tommi Kaplas Yuri Svirko Victoria V Rutckaia Andrey A Lipovskii 《Nanoscale research letters》2012,7(1):676
We demonstrate that silver nanoisland film self-assembled on the surface of silver-containing glass in the course of thermal processing in hydrogen is capable to detect 10−7 M concentration of rhodamine 6G in water using surface enhanced Raman spectroscopy (SERS) technique. The film can be multiply restored on the same glass substrate via annealing of the glass in hydrogen. We showed that the film can be self-assembled after as much as ten circles of the substrate cleaning followed by annealing. The proposed technique of the silver nanoisland film formation enables multiple usage of the same glass substrate in SERS experiments. 相似文献
10.