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时光的脚步悄然跨过了2012年,我们满怀收获的喜悦迎来了2013年.站在新的起点上,赤水河航道人将开启更加美好的明天.
2012年带给赤水河航道人太多难忘的美好记忆,这支为实现航道畅通贡献了青春、热情和汗水的水上"铁军"收获了许多梦想: 相似文献
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2001年5月17日,南京外轮代理公司船务部受“亚洲收获”号外轮船长的委托,向南京水上消防监督站申请消防监护,称韩国大宅船务有限公司“亚洲收获”号货轮在泰国的科希港锚地装载了4万1千吨木薯干.于2001年5月14日01时12分(泰国时间)启航. 相似文献
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《中国远洋航务公告》2011,(12):50-56
2011年国际海运(中国)年会闭幕后,许多代表反馈了他们的参会感想、收获及建议。现刊出部分来自行业组织、投行、货主、媒体、港航企业的代表的反响。 相似文献
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Downward fluxes of organic biodeposits under suspended mussel culture cause benthic impacts such as microbial mat production. Quantifying sediment erosion in these coastal ecosystems is important for understanding how fluxes of organic matter and particulates contribute to benthic–pelagic coupling. Critical shear velocity (u?), erosion rates and particle size distributions of resuspended sediment were measured at two sites; an impacted muddy site with extensive mussel culture (site 1), and a coarser sandier site with less mussel influence (site 2), using a new method for assessing sediment erosion at Tracadie Bay, Prince Edward Island in August 2003. Shear forces were generated by vertically oscillating a perforated disc at controlled frequencies. These forces correspond to shear velocity, using a re-designed and calibrated Particle Erosion Simulator. Undisturbed sediment cores obtained by divers and grab (sub-cored using a Plexiglas? cores) were exposed to shear stress to compare differences between collection methods. Microbial mats were present at site 1 which initially biostabilized sediment against erosion due to ‘armoring’ of the sediment, but onset of erosion was abrupt once these mats failed. Erosion sequences at site 2 (without mat cover) were smoother resulting in less material being eroded. Mean mass of material eroded was 47 and 23 g m? 2 min? 1 at sites 1 and 2 respectively. Mat area cover and shear velocity was strongly related. Critical shear velocities varied between 1.70 and 1.77 cm s? 1, with no obvious differences between location or collection method, so sediments from these two contrasting sites had identical mean critical shear velocities. Significant differences existed in the concentrations of chlorophyll a, colloidal and bulk carbohydrates, between mats and bare sediment from site 1. Particle sizes measured by videography of resuspended sediment at different shear velocities ranged from 100 μm (the minimum diameter capable of being detected by the system), to large mat fragments of 1700 μm for both sites. These results provide evidence of the relevance of using a portable erosion device to indicate how sediment erodability is affected by mussel–microbial relationships. 相似文献
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Jon Grant Cedric Bacher Peter J. Cranford Thomas Guyondet Michel Carreau 《Journal of Marine Systems》2008,73(1-2):155-168
A fully-coupled biological–physical–chemical model of a coastal ecosystem was constructed to examine the impact of suspended mussel culture on phytoplankton biomass in Tracadie Bay, Prince Edward Island, Canada. Due to the extent of mussel culture there, we hypothesised that shellfish filtration would control the concentration and distribution of phytoplankton and other suspended particles in the bay. Circulation was delineated with a tidally-driven 2D numerical model and used to drive an ecosystem model with a focus on pelagic components including phytoplankton production, nutrients, detritus, and mussels. The benthos were treated as a sink. Nutrients and seston were forced by tidal exchange and river input, with phytoplankton additionally forced by light. Boundary conditions of seston and nutrients were derived from field studies with an emphasis on the contrast between spring (high river nutrients, low temperature) and summer (low river inputs and high temperatures). Model output was used to map phytoplankton carbon over the bay for each season and in the presence of mussels and river nutrient input. Results indicate severe depletion effects of mussel culture on overall phytoplankton biomass, but no spatial pattern that can be attributed to grazing alone. Primary production generated by nutrient-rich river water created a mid-bay spike in phytoplankton that dominated the spatial pattern of chlorophyll-based carbon. Model results were validated with surveys from a towed sensor array (Acrobat) that confirmed the river influence and indicated bay-wide depletion of 29% between high and low water. Our model results indicate that the farm-scale depletion emphasised in previous studies cannot simply be extrapolated to seston limitation at the ecosystem level. 相似文献
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John H. Simpson Barbara Berx Joanna Gascoigne Camille Saurel 《Journal of Marine Systems》2007,68(3-4):556-568
Time series measurements of flow and pigment concentrations (Chl) in the Menai Strait have revealed that the strong residual flow in a tidal channel ( 500 m3 s− 1) transports phytoplankton from the open sea into the channel where much of it is consumed by suspension feeders, mainly in commercial beds of Mytilus edulis. The progressive depletion of phytoplankton along the channel results in a strong horizontal gradient of plankton and hence Chl. Tidal displacement of this gradient causes large (± 50% of mean) oscillations of Chl in the vicinity of the mussel beds. Vertical mixing by the strong tidal flows is sufficiently vigorous for most of the tidal cycle to ensure that downward diffusion can resupply the near-bed layer although there are indications of some transient depletion around slack water.This paradigm of the interaction of advection, diffusion and filtration determining the distribution of plankton and its supply to mussels has been encapsulated in a series of simple models forced only by boundary values. In the first, a 1-D model of tidal flow in the channel reproduces the principal features of the observed currents including the unusually large spatial change in phase of the currents and the variation of the residual transport with tidal range. The flow field from this physical model is used to drive a second model based on the advection diffusion equation for Chl with a source at the Irish Sea boundary and a sink over the mussel bed. This model illustrates the formation of a strong Chl gradient along the channel and simulates the amplitude and phase of the M2 oscillations of Chl and the development of the M4 variation apparent in the observations. This second model has been extended to 2-D over the mussel beds to allow investigation of the effects of water column mixing. The model indicates that only for a short period ( 30 min), close to slack water, is mixing sufficiently reduced to permit the development of a depletion boundary layer and then only within 1 m from the bottom, a result which is consistent with the observations. 相似文献
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The New Zealand aquaculture sector, consisting of mainly mussel, oyster, and salmon farmers, has been expanding over the last two decades. The increasing demand for water space for marine farming has prompted a process of community consultation and legislative reform resulting in the Aquaculture Reform Act 2004. Despite efforts to develop more effective legislation and improve the application process, marine farmers have often been relatively unsuccessful at gaining the water space that they desire for the expansion of the industry. However, social factors such as landscape and amenity values, recreational and navigational use, and alienation of public space are the most frequently cited reasons for the refusal of marine farm consent applications. An analysis of resource consent decision records from the past decade demonstrates this conclusion that the main factor limiting the further expansion of the aquaculture industry in New Zealand is the social carrying capacity, in the context of a period of legislative transition. 相似文献
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Kailin Kroetz Daniel K. Lew James N. Sanchirico Pierce Donovan 《Coastal management》2019,47(2):207-226
The Pacific Halibut Catch Sharing Plan formalized the process for allocating halibut between the Alaska commercial and recreational charter sectors. It included a new program intended to allow for “flexibility” through inter-sectoral trading, permitting charter operators to lease commercial halibut pounds to relax client harvest restrictions. Here we evaluate the first two years of lease market activity and participation. Participation from some commercial quota holders in the lease market suggests that the program provided beneficial flexibility; in fact, the number of transfers to the charter sector was greater than transfers within the commercial sector for some quota types. We also identified a high proportion of self-leasers. However, transfers to the charter sector were on average smaller than within-sector commercial transfers, and total poundage leased by the charter sector was low compared with commercial transfers. Usage of leased quota by the recreational charter sector enables the harvest of larger fish or additional fish, and provides flexibility in catch composition on halibut closure days. Finally, the value-per-pound may be higher in the charter sector, as commercial-to-charter transfer prices approached the commercial ex-vessel price. 相似文献
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《中国港口》2004,(10):4-4
<正>Dear readers: Golden autumn of October suggests a harvest season and vitality in port business as well.Agreat number of ports and harbours across the country have actively made their contributions to ourMagazine in attempt to reflect their business achievements.Unfortunately we are unable to publishall articles,instead,we selectly release the information of break-through traffic records includingcontainers by port of Shenzhen that is really inspirative.We actively prospect overwhelmingly busi-ness situation in port industry in the country. 相似文献
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Nan Evans 《Coastal management》2013,41(3):189-213
Abstract Greater commitments of aquatic resources are required as aquaculture activities expand and intensify. At the same time, increasing recreational and residential uses of the coast are placing other demands on many of the same resources. Multiple use disputes are arising and conflicts are intensifying. This paper is a problem analysis based on recent public debates in the state of Washington which surrounded the mechanical harvest of clams, raft culture of mussels, and pen rearing of salmon. Subjects of potential conflict are shown in the questions of continuing the subtidal harvest of geoducks, raft culturing of marine algae for food and chemical extracts, and continuing the use of public nearshore aquatic areas for private oyster farming. This report also suggests that better coastal management techniques need to be developed which address: (1) how environmental impacts and risks are determined; (2) how claims for esthetic quality can be evaluated and measured; and (3) which methods can be used to plan for the aquatic areas which recognize the special features of the aquatic areas. 相似文献
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贝叶斯网络是近年来人工智能领域最重要的研究成果之一,在具有不确定性的推理和决策问题中得到了广泛的应用。以贝叶斯网络及其推理机制为基础,主要研究了贝叶斯网络在辐射源威胁等级评估方面的应用。选取了部分影响因素,建立了基于贝叶斯网络的辐射源威胁等级评估模型。最后通过一个计算机仿真实例验证了算法具有连续性和累积性,能够对辐射源威胁等级做出较准确评估。 相似文献
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通过室内试验,讨论了采油平台的冲淘机理和防护措施,针对仿生海底、仿生林、抛石块、抛石子袋等防冲淘措施进行了方案设计和试验,完成了导管架式、桶形基础式、沉垫式三种采油平台的冲淘及防护试验,提出和完善了多层次抛石防护技术,并将研究成果成功地应用于海上防护工程。 相似文献