共查询到18条相似文献,搜索用时 171 毫秒
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目前.有数种无损探伤检验(NDE)技术用于检测焊缝缺陷.如磁粉检测(MP).液体渗透检测(LP)、超声波检测(UT).X光检测(RT)和涡电流检测(ET)。它们各有各的优势.也各有各的不足。 相似文献
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随着铝合金材料的普及使用,作为先进数字化检测手段的相控阵超声波检测(Phased Array Ultrasonic Testing, PAUT)技术应用备受关注。近年来,在先进超声波技术发展和应用需求结合下,陆续开展的相关试验研究为铝合金搅拌摩擦焊焊缝PAUT技术提供指导和规范引领,并形成相关行业应用标准。铝合金气体保护焊PAUT技术的应用需求逐渐显现,但相关研究和标准尚在起步阶段。梳理国内铝合金焊缝PAUT技术应用现状,可为推动铝合金焊缝PAUT技术研究、扩展应用场景提供技术基础。 相似文献
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The term Demand-Responsive Transport (DRT) has been increasingly applied in the last 10 years to a niche market that replaces or feeds (usually via small low floor buses or taxis) conventional transport where demand is low and often spread over a large area. More recently, the concept of DRT as a niche market has been broadened to include a wider range of flexible, demand-responsive transport services and is increasingly referred to as Flexible Transport Services (FTSs). The contention of this paper is that well-implemented FTS has the potential to revitalise bus-based public transport services which are traditionally based on fixed networks with variable geographical coverage and levels of service. 相似文献
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以往软件测试过程中测试用例的数据准备都由测试人员人工设计并驱动被测软件,这种方法有着效率低下、测试用例可重用性差等缺点。文章以模型驱动的基本思想为指导,以仿真组件的可重用性为目标,设计出一个基于MDA的信息对抗软件测试仿真平台。该平台能够根据不同被测软件的需要,通过仿真提供测试数据,并且可以依据不同军事想定灵活地定制输出数据的类型和格式。 相似文献
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The successful provision of Demand Responsive Transport (DRT) in Europe, Australia, UK and the US has been addressed in several substantial studies and projects. The general finding of these studies is that DRT is a suitable transport solution in particular areas and can deliver social inclusion and community building objectives. Existing research confirms that DRT is particularly useful for connecting isolated communities and population groups to essential services such as healthcare and is cost-effective in terms of contributing greatly to community wellbeing. However, many existing DRT services are still not performing to their true potential, and many of them could not be viable as commercial services. The aim of this study is to develop greater understanding of DRT services from the passengers’ perspective using a case study of LinkUp in Tyne and Wear, one of the most successful DRT schemes in the UK. The paper has two key objectives: (a) to critically review, in the context of the detailed case study the general characteristics of the selected DRT scheme; and (b) to analyse and interpret the findings from a detailed survey of users (who are predominately elderly and female) with regard to passenger characteristics, their attitudes and perception of the service and their suggestions for improvement. 相似文献
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This paper presents a new formula for prediction of the dynamic hardening effect for various marine structural steels, considering dependencies on the strain rates and temperatures. Dynamic tensile tests are carried out for three kinds of marine steels, 2W50, EH36, and DH36, changing the steel layer in the thickness direction, the strain rates, and temperatures. Considering two thickness layers at the middle and surface, five strain rate levels of 0.001/s, 1/s, 10/s, 100/s, and 200/s, three temperature levels of LT (−40 °C), RT, and HT (200 °C), and two repetitions, the total number of tests is 180. Dynamic hardening is clearly seen at LT and RT regardless of the material type, while dynamic strain aging occurs at HT, leads to negative strain rate sensitivity, and thus elevates the quasi-static flow stress above the dynamic flow stress to a certain strain rate. Dynamic hardening factors (DHFs) are derived as a function of the proof strains of 0.05, 0.10, and 0.15 according to each material type and temperature level. A new formula to determine the material constant D of Cowper–Symonds constitutive equation is developed. The correctness of the proposed formula is verified through comparison with test flow stress curves and reference test data in large plastic strain and high strain rate ranges. 相似文献