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历时84天的西向环球航行
我以前做过杂货船的水手、三副、二副、大副和船长,后来又当过多用途货船和小型集装箱船的船长,最终成为一艘大型集装箱船的指挥者.比较典型的航程是多次参与一艘大型集装箱班轮历时84天的西向环球航行——从上海港出发,在上海港引航员引领下驶出长江口,开往东海;在中国香港、新加坡短暂停留后,穿越马六甲海峡,经印度洋、亚丁湾、红海,过苏伊士运河,一路挂靠热那亚、巴塞罗那、瓦伦西亚,而后出直布罗陀海峡,跨越北大西洋,停靠纽约、萨瓦那、迈阿密,穿越巴拿马运河后,继续西行,旁经墨西哥海岸,停靠长滩、西雅图、温哥华,最终横渡北太平洋,经津轻海峡,入日本海,回到上海的母港. 相似文献
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隆德县把小流域综合治理与新农村建设结合起来,走"政府引导、农民主体、部门联动、社会参与"的原则,因地制宜、突出重点、综合治理,立足改善当地生态条件和生产条件,通过治理水土流失、调整农业产业结构、培育特色种植业,增加了农民收入、居住环境好转、基础设施加强、生产得到发展,民风、村貌改善,推动了流域新农村建设的全面发展。 相似文献
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蔡朋岑 《舰载武器(含VCD光盘)》2007,(3):33-37
美军布雷、北越求援雷
1972年3月30日,越南人民军和南方人民武装力量发动春季攻势,同时展开几个大规模的兵种协同进攻战役,兵锋直指南越北部的广治、中部的昆嵩、南部的平隆三个战略方向,在地方武装力量和群众政治力量的配合下,先后解放广治、新境、德都、禄宁,围困安禄,取得了节节胜利,沉重打击了南越政权。美国为了切断来自越南北方的支援,保住阢文绍傀儡政府,争取巴黎和谈的有利条件,在大举增调海空兵力、恢复轰炸越南北方的同时,于5月9日开始对越南北方沿海航道、港口、河道实施大规模的水雷封锁。仅5月9日清晨就出动海军舰载机100余架,各型舰只6艘,在对海防、广安、鸿基、涂山等沿海地区进行轰炸和炮击之后,即以A-6A、A-7E型舰载机40余架实施布雷,其后还多次进行补充布雷,逐步扩大范围,先后封锁了海防、勒苗等重要海上航道以及太平河、马江、格会口、格梭口、筝河、日丽河、城门河、红河口、文奥河、茶李河、勒县河、格禁河等内河航道。 相似文献
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山西地处华北西部的黄土高原东翼,属于典型的非水网地区,全省通航总里程1234公里,其中,黄河流经山西省4个市、19个县(市、区),通航里程971公里,是与蒙、陕、豫的天然分界线,沿黄地区经济发展缓慢,自然条件恶劣,渡运是两岸百姓生活、农作、交流的主要运输工具之一,具有点多、线长、面广的特点,船员大多数属于当地村民, 相似文献
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一、概述
海洋是地球的重要组成部分,是人们赖以生存的基础,也是世界经济发展、文化交流、文明进步、货物贸易的第一媒介。自人类有记载的历史以来,人们对海洋灾害或突发性的自然灾害,如:热带气旋(温带气旋)、台风(飓风)、风暴潮、大风、巨浪,严寒、海冰、海雾、地震、海啸等有着较为全面的认识并通过智慧规避这些海洋灾害的影响。 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