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郭明明 《船舶标准化工程师》2020,53(3):78-82
主要结合某救护艇建造过程中的下水及转运过程,根据救护艇结构特点设计吊运托架,结合数据理论分析及实际试验操作,论证吊运托架整体吊运下水及转运技术的可行性及安全性,为小型铝质船舶托架吊运下水及转运提供技术支持,并达到降低下水及转运过程成本、提高下水及转运效率的目的。 相似文献
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本文结合研发及生产实践,介绍了武钢CSP检化验室试样自动输送及分拣系统的系统组成、系统功能及特点。该系统为第一条国产化的试样自动输送及分拣系统,其功能及先进易用性达到了国际水平,具有极大的推广价值和应用前景。 相似文献
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重点研究美国航母及编队导航系统的核心——导航传感器系统接口(NAVSSI)的系统构成及主要功能,分析美国航母及编队导航系统从数据输入、数据检查、数据处理到数据分发的整个信息流程及信息安全问题,并总结美国航母及编队导航系统的特点. 相似文献
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目前设计规范未对人字门启闭力计算公式中的闸门前后水压差Z值选取做出明确规定,在计算人字门启闭力时通常会取大值,从而导致工程浪费。对大藤峡船闸人字门水动力与启闭特性进行数值模拟和物理模型试验研究,定量分析启闭力影响因素的效果,以便更科学合理地选取Z值。结果表明,适当增大门底间隙、门龛深度和采用变速启闭运行方式有利于闸门前后水体流动顺畅,在闸门启闭过程中形成的Z值则较小,相应的人字门启闭力也变小。综合考虑人字门启闭运行水动力特性的影响因素,合理选取Z值,可得到比较准确的计算结果,优化启闭机容量。 相似文献
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Coleen L. Moloney Michael A. St John Kenneth L. Denman David M. Karl Friedrich W. Köster Svein Sundby Rory P. Wilson 《Journal of Marine Systems》2011,84(3-4):106-116
Marine food web dynamics are determined by interactions within and between species and between species and their environment. Global change directly affects abiotic conditions and living organisms, impinging on all trophic levels in food webs. Different groups of marine researchers traditionally study different aspects of these changes. However, over medium to long time scales perturbations affecting food webs need to be considered across the full range from nutrients to top predators. Studies of end-to-end marine food webs not only span organism sizes and trophic levels, but should also help align multidisciplinary research to common goals and perspectives. Topics are described that bridge disciplinary gaps and are needed to develop new understanding of the reciprocal impacts of global change on marine food webs and ocean biogeochemistry. These include (1) the effects of nutrients on biomass and production, (2) the effects of varying element ratios on food web structure and food quality, (3) bulk flows of energy and material in food webs and their efficiencies of transfer, (4) the ecological effects of species richness and the roles of microbial organisms, (5) the role of feeding behaviour in food web dynamics and trophic controls, (6) the spatial dynamics of communities and links between different food webs, (7) the combined effects of body size and behaviour in determining dynamics of food webs, and (8) the extent to which the ability of marine organisms (and communities) to adapt will influence food web dynamics. An overriding issue that influences all topics concerns the time and space scales of ecosystem variability. Threads link different nodes of information among various topics, emphasizing the importance of tackling food web studies with a variety of modelling approaches and through a combination of field and experimental studies with a strong comparative approach. 相似文献
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从河床特性与演变角度评长江中下游张家洲浅水航道的开发与整治 总被引:2,自引:0,他引:2
长江中下游张家洲河段属分汊河床,由“张家洲”江心洲将河床分为南港与北港。在枯水期南港与北港的诸浅滩水深不足3.8m,严重影响航运。本文根据地理调查,近100年来历史航道图的比较,航道水深的测量值,以及河床水力几何形态关系的分析,着重研究了张家洲浅水航道的河床演变与南北两港及其浅滩的河床水力几何形态,探讨的成果可作为张家洲浅水航道的整治以及长江中下游航道的开发规划与建设的参考。 相似文献
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Abstract This article reviews the conflicts that led to the establishment of a special Congressional Committee on offshore oil and gas exploration, development, and production and the attempted resolution of various issues by that Committee and the Congress in the 1978 Amendments to the Outer Continental Shelf Lands Act of 1953. A short review is provided of the history of Outer Continental Shelf (OCS) development, of the conflict between the federal government and other interested entities and persons, and of the Congressional mechanism to respond to these conflicts. A more detailed analysis is provided of the most significant OCS issues. The article describes the various risks and benefits of offshore activity and the various benefits and risks of proposed changes in the law concerning such development. A review of the Congressional mechanism to assess these risks and benefits and balance them is included in a discussion of the various issues and legislated solutions. Finally, the article notes the need for continuing oversight and review of the benefits and risks and how effective the 1978 Amendments are in balancing them. 相似文献
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重型荷载下港口道路和堆场的地基工作区及压实深度研究 总被引:1,自引:0,他引:1
随着港口机械大型化、重型化的高速发展,由于地基变形导致的港口道路和堆场沉陷、变形、开裂等病害十分突出,现有规范关于地基压实的标准已难以满足设计使用要求.研究了重型荷载作用下港口道路、堆场的地基工作区范围及压实深度.提出了相应的加固措施. 相似文献