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橡胶输送带在散货物料转运设备中占有重要的地位。因此,如何使输送带的损伤得到尽快的修补,确保物料运输正常进行是维修人员的一个重要课题。分析了输送带常见损伤种类及原因,对多种修补方式效果进行了对比讨论,提出了一套切实可行的冷粘修补工艺,提出了提高冷粘质量的措施,对指导输送带维修具有实际意义。 相似文献
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由上海海运局和上海橡胶研究所、上海胶体化工厂研制的S-2聚硫密封胶、YSM-1型松锈润滑剂已于去年十二月鉴定,现正在上海海运局下属各船厂推广应用。船舶在航行中发生设备、管道破损泄漏等故障,过去都是沿用焊接修补,费时费力。且易引起火灾事故。自一九七九年起,上海海运局就进行了以粘代焊的研究工作,研制了多种密封胶,其中S-2聚硫密封胶曾对60多艘次船舶的上百个工程项目进行修补和密封,在防火防爆,节约能源,降低修理费,挽救报废设备等 相似文献
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文中简述的裂缝缺陷修补是在北疆水源水库引水泄洪洞工程的技术处理方法,修补质量较好,效果显著,可以作为同种砼缺陷修补的成果应用。 相似文献
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[目的]针对金属I型夹芯板界面的脱粘失效破坏,开展金属夹芯板界面疲劳脱粘特性分析。[方法]基于内聚力模型理论,考虑时间历程、三维结构节点多自由度的损伤演化方程与收敛判定准则,开发适用于三维复杂结构的界面疲劳脱粘模拟程序;与焊接接头脱粘实验结果进行对比,验证所开发程序的准确性,并进一步对钢制金属I型夹芯板的界面疲劳脱粘行为进行数值模拟。[结果]结果显示,所开发的三维界面疲劳脱粘数值模拟程序与焊接接头脱粘实验间最大的模拟误差仅为14.05%;I型夹芯板承受面外载荷时,夹芯板界面处的脱粘破坏主要表现为沿焊缝方向的表面裂纹扩展,当裂纹扩展至夹芯板长度的70%左右时,裂纹开始贯穿腹板形成贯穿裂纹。[结论]所开发的三维复杂结构界面疲劳脱粘程序可以实现对金属夹芯板界面疲劳脱粘寿命的有效评估,对实际工程应用具有一定的指导意义。 相似文献
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本文通过对混凝土结构裂缝、缺陷等的检查评估,选用适宜的修补加固材料和方法,介绍裂缝的分类和产生的原因以及如何诊治;并介绍通过修补加固材料的特性以及其适用的修补方法和部位。使其取长补短,既达到修补加固的目的,又经济合理。 相似文献
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针对船用设备穿孔、裂纹等损伤的应急抢修,文中提出了便携式船用粘接——堵漏应急修补工具箱的研制思路和遵循原则,并对修补工具箱组成设计、修补材料研制、修补工具箱小型化研究等关键技术问题进行了阐述。 相似文献
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为了研究蓄冷材料在舰船空调系统中的应用,分别对冰和某型高温相变蓄冷球两种材料的蓄释冷过程用有限元分析方法进行了模拟仿真,找出蓄冷量和蓄释冷时间的变化规律,并分析比较两种材料的蓄释冷的性能,结果表明:采用高温相变材料,其蓄冷周期短,制冷机组相对较节能,可满足水面舰船蓄冷空调的要求. 相似文献
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粘钢加固法在铁路框架桥加固中的应用 总被引:1,自引:0,他引:1
介绍粘钢加固的特点,并结合甬台温铁路东外环立交桥的加固设计实例对粘钢加固法的计算理论、加固材料及加固方法进行了分析阐述,并提出了粘钢加固应注意的问题,可供类似铁路桥梁加固参考。 相似文献
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Burke Hales Robert D. Vaillancourt Laura Prieto John Marra Robert Houghton Dave Hebert 《Journal of Marine Systems》2009,78(3):426
We present the observations from a pair of field experiments at the New England shelfbreak front in June and August of 2002, each consisting of 14 cross-frontal surveys using the Lamont Pumping SeaSoar. Measurements of the front's physical, chemical, and bio-optical characteristics were made at high spatial and temporal resolution. The front, based on water-column hydrographic distributions, was found within a few km of the 200 m isobath during both cruises. We present here composite sections, based on averages of individual sections shifted in space to a common frontal location, of the cross-frontal distributions of these properties as a measure of the mean state of the front in both June and August. The observations show the familiar temperature, salinity, and density distributions of the summertime front, dominated by surface thermal heating. Nutrient and bio-optical distributions show the combined effects of water-mass exchange and biological processes. T, S, silicate, and phosphate distributions are suggestive of cross-frontal exchange of slope- and shelf waters, although transport mechanisms and pathways are not apparent. These properties, along with nitrate and optical measures of the suspended particle distributions, show vertical displacements of isopleths as the front is approached: property contours slope upwards toward the front from the shoreward side, and downwards toward the front from the seaward side. Again, actual water-movement pathways are not constrained by these suggestive patterns. Bio-optical distributions show elevated indicators of photosynthetic efficiency both seaward and shoreward of the front, but the front itself is a minimum in biomass. Accumulation of photosynthetic biomass appears to be controlled primarily by nitrate scarcity in waters within and above the pycnocline. At the base of the pycnocline, light limitation appears to be the controlling factor, although the base of the euphotic zone is deeper than the biomass maxima and the base of the pycnocline. Mechanisms explaining this phenomenon are unclear, but tenuous evidence suggests low stratification at the depth of the 1% light level may not allow phytoplankton to optimize for the low-light, high-nutrient conditions at depth. Cross-frontal differences in nutrient and bio-optical parameters, particularly in August, suggest distinct phytoplankton assemblages, and the presence of calcite-forming or nitrogen fixing groups to the community structure, especially in very shallow waters across the front and in pycnocline waters seaward of the front. 相似文献
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装备维修是生产制造、作业运转的基础,特别是在船舶、航空等领域。由于在维修过程中装备结构复杂、维修人员经验技术不足和缺少直观维修手段导致容易导致维修效率低下和操作出错。因此,通过研究基于增强现实的装备维修方案,直观交互地进行维修作业,能够有效地提升维修的质量和效率。由于装备体型较大,结构复杂,给跟踪定位带来了新的困难,针对实际的工程需求,创新性地将主流方法进行结合,提出了多Marker和ORB-SLAM混合跟踪的方法。通过二次调整多Marker定位结果的动态权值,提高局部定位维修的精度和可靠性。分析比较现有的特征点算法,选择ORB-SLAM作为方案,实现全局的定位和导航,对维修过程给以指导,并设计开发装备诱导维修系统,为大型复杂设备地维修提供了通用解决方案。 相似文献
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A few cities in some of the larger developing countries in Latin America and Asia have made increasing use of multi-year concessions or franchises, competitively awarded to private companies, for construction and operation of urban transport infrastructure and for provision of public transport services. In view of the strong prospective growth of developing-country cities with large transport needs, and the rise in the emerging economies of potential new sources of private capital, it is important to see how effective PPP has so far been in this area. The experience is analyzed principally by thorough comparative review of what has actually happened for some of the main users to date: Bogotá, Santiago, São Paulo, Seoul, and several cities in both China and India. Despite delays and mistakes that have been made in development of most of the projects, the overall results, already delivered and in prospect, are very positive and urban public transport is benefiting substantially, with significant side effects on poorer people's access to work and to services, air pollution levels and road accident rates. The widest and most important advantage of the PPP arrangements, as compared with more conventional short-term contracting, is found to be the innovations, technical and managerial, developed, and, in particular, the mutual capacity building of the countries' private and public sectors and their more effective interaction. The experience in the six countries covered suggests that other developing-country cities may be best assisted to develop sound urban transport PPPs more rapidly through provision of help on chosen items among 7 elements that have proved particularly crucial but sometimes weak in the projects reviewed: Civic consultation systems, Land-use/Transport strategic planning, Land/property market management, Monitoring systems, Progressive policies, Economic regulation, and Public institutional framework for PPPs. 相似文献
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The effects of variability in environmental conditions on species composition in benthic ecosystems are well established, but relatively little is known about how environmental variability relates to ecosystem functioning. Benthic invertebrate assemblages are heavily involved in the maintenance of ecological processes and investigation of the biological characteristics (traits) expressed in these assemblages can provide information about some aspects of functioning. The aim of this study was to establish and explore relationships between environmental variability and biological traits expressed in megafauna assemblages in two UK regions. Patterns of trait composition were matched to environmental conditions and subsets of variables best describing these patterns determined. The nature of the relationships were subsequently examined at two separate scales, both between and within the regions studied. Over the whole area, some traits related to size, longevity, reproduction, mobility, flexibility, feeding method, sociability and living habit were negatively correlated with salinity, sea surface temperature, annual temperature range and the level of fishing effort, and positively associated with fish taxon richness and shell content of the substratum. Between the two regions, reductions in temperature range and shell content were associated with infrequent relative occurrences of short-lived, moderately mobile, flexible, solitary, opportunistic, permanent-burrow dwelling fauna and those exhibiting reproductive strategies based on benthic development. Relationships between some traits and environmental conditions diverged within the two regions, with increases in fishing effort and shell content of the substratum being associated with low frequencies of occurrence of moderately mobile and moderately to highly flexible fauna within one region, but high frequencies in the other. These changes in trait composition have implications for ecosystem processes, with, for example, reductions in permanent-burrow dwellers within one of the regions potentially compromising the ability of the assemblages to process and store chemicals and waste products. However, the connections between environmental conditions and trait composition are complex and incorporate many factors. Experimental investigations will be necessary to determine the extent and consequences of these important relationships. 相似文献
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通航节制闸运行调度原则与常规的船闸工程和水闸工程明显不同,针对其口门宽度、门槛水深、闸门形式、平面布置等关键技术问题,船闸工程和水闸工程规范尚无具体的要求。以邓楼节制闸重建工程为例,对现有的节制闸运行调度原则进行调整以满足开通闸通航的要求,同时通过实施工程补偿措施以满足原节制闸防洪水倒漾、引水灌溉、保护水质的功能。通过理论计算和对比分析等方法得知建设2孔净宽23 m、门槛水深5. 5 m的通航节制闸能够满足船舶安全通航和航道通过能力的要求,并得出"升卧式平面闸门能够适应长期低水头运行、高通航保证率要求特点"的结论。其确定运行规则、建设规模、闸门形式、布置方案的方法对类似项目的建设及船闸标准规范的完善均有借鉴意义。 相似文献
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航道工程具有施工工期长、施工影响因素多等特点。在航道工程的设计、施工、维护的各个阶段,随着对精细化管理的需求日趋提高,传统的实施方法已不能满足工程的强度与精度要求。从航道工程和BIM的特性入手,探讨了BIM技术在航道工程设计、施工、维护等各阶段的应用。在保证设计合理性的前提下,可通过BIM模型完成设计意图的表达与传递,从而保证航道工程的施工质量,以及后续维护阶段航道整治建筑物安全、稳定地发挥其作用。 相似文献