Aerodynamic characteristics of a hybrid trimaran model     

Konstantin I. Matveev  Victor A. Dubrovsky 《Ocean Engineering》2007,34(3-4):616-620

Ultra fast marine vehicles can substantially benefit from aerodynamic unloading. The subject of this study is aerodynamics of a hybrid trimaran that comprises three wave-piercing planing hulls and a wing-shaped superstructure. This configuration is characterized by high efficiency and good seaworthiness at speeds about twice those of contemporary fast ferries and combat ships. Aerodynamic coefficients of the above-water structure of the hybrid trimaran were measured in a wind tunnel. A computer code based on the vortex lattice method is applied for modeling steady aerodynamics of this structure in a range of attack angles. The application of an interceptor at the pressure side of the wing is shown to produce significant increase in aerodynamic lift.  相似文献   

Distribution of molluscan remains in the sediment of the Chukchi Sea and its vicinity, the Arctic     

Gao Aiguo  Xu Fengshan  Sun Haiqing  Li Lon 《海洋学报(英文版)》2003,22(4):607-619

INTRODUCTIONInordertostudythemarinesedimentationoftheChukchiSeaandBeringSeaandgathertheinformationofpaleoceanographyandpaleoenvironment,theFirstChineseNationalArcticResearchExpeditionTeamcollectedbenthonicmolluscansamplesintheChukchiSea ,BeaufortSeaandBeringSeafromJuly 1sttoSeptember 9th ,1 999byicebreakerXuelong .ItwasnotonlythefirstsamplingthatChinesescientistscollectedmolluscaremainsinabove mentionedar eas,butalsooneofinvestigationsinasinglecruisewithhighersamplingrateandalotofb…  相似文献   

Cross-scale linkages and adaptive management: Fisheries co-management in Asia     

Douglas Clyde Wilson  Mahfuzuddin Ahmed  Susanna V. Siar  Usha Kanagaratnam 《Marine Policy》2006

The present paper reviews research done in Asian countries during the second phase of the Worldwide Collaborative Research Project on Fisheries Co-management. Building on the results of the first phase, the paper focuses on stakeholder conflict, and social and geographical scale. Several conclusions emerge from common patterns. Community motivations for co-management are often related more to the protection of fisheries resources from outsiders than to conservation. Access rights are important but exclusion from food resources in a context of widespread poverty should be approached carefully. Cross-scale institutional linkages make adaptive management possible by bringing together groups with broad local foci and ones with narrow trans-local mandates. The role of the government is balancing interactions between these various groups. This is not a role that is compatible with top-down management.  相似文献   

Governance characteristics of large marine ecosystems     

Robin Mahon  Lucia Fanning  Patrick McConney  Richard Pollnac 《Marine Policy》2010

The Large Marine Ecosystem (LME) concept is widely established as a large-scale approach to coastal and marine management. LME-oriented activities have focused mainly on natural sciences. Socioeconomic and governance aspects have only recently been receiving increased attention. The 64 LMEs that have been defined appeared to exhibit considerable diversity in characteristics that would be expected to affect governability. This paper explores two questions: (1) Do the LMEs vary widely enough in geopolitical complexity that different approaches to governance may be required for different LMEs? (2) Are there groups of LMEs within which one might take similar approaches to governance? The analysis demonstrates that there is considerable heterogeneity among LMEs with regard to characteristics that would be expected to affect governability. It concludes that a diversity of governance approaches will be required to cope with this heterogeneity. It also appears that LMEs can be grouped according to these characteristics. This suggests that different approaches could be considered for clusters rather than for individual LMEs and that there can be sharing of experience and learning within clusters. The types of relationships between features of LMEs and the ‘best’ approaches to marine governance are discussed in the context of emerging governance ideas.  相似文献   

产业融合背景下的舟山海洋文化产业新发展          下载免费PDF全文

李智  马丽卿 《海洋开发与管理》2018,35(1):28-32

随着舟山群岛海洋文化产业的不断开发和旅游产业的体系日益成熟,两大产业呈现出相互渗透相互融合的态势,带来了舟山海洋文化产业发展的新契机。文章阐释了产业融合的内涵和对舟山海洋文化产业发展的推动意义,剖析了舟山海洋文化产业发展的历史、现状以及所面临的缺乏文化资源转化为产能、传统文化表现手法陈旧、缺少大规模市场等问题,提出了旅游产业与海洋文化产业的融合路径和舟山海洋文化产业发展需要改造传统文化产业,创新文化产品;运用现代科技,促进海洋非物质文化旅游发展;加快发展文化内容产业,促进产业结构调整;充分运用政府引导作用,推进海洋文化产业与旅游产业深入融合;培育大型企业,扶持中小型企业,形成文化产业规模效应;加大教育投入,培养高素质人才等相关性策略。  相似文献   

Shallow Water Dissipation Processes for Wind Waves off the Mackenzie Delta     

Fumin Xu  Steve Solomon 《大气与海洋》2013,51(3):296-308

This study focuses on two physical processes for waves in shallow waters off the Mackenzie Delta: bottom friction and depth-induced breaking terms. We use field observations of winds and waves, the state-of-the-art Simulating Waves Nearshore (SWAN) model, and reanalysis wind and wave data. The two field observation periods are an August 2008 field experiment, during which in situ field data were collected, and an Arctic storm when data were recorded by buoy measurements from 4 to 6 August 1991. Wind and wave development processes are analyzed during these two periods with comparisons to observed winds and waves. Our analyses show that bottom friction is the main shallow water physical process during the August 2008 field experiment, whereas depth-induced breaking is the dominant shallow water physical process during the 4–6 August 1991 storm, in conjunction with the effects of bottom friction. The SWAN wave model is used to investigate the shallow water physical processes during these two observation periods. Simulation results indicate that the model can give reasonable results, with an appropriate Collins coefficient of 0.006 and a wave breaking parameter of 0.55 to represent bottom friction and depth-induced breaking physics, respectively.

RÉSUMÉ?[Traduit par la rédaction] Cette étude porte sur deux processus physiques concernant les vagues dans les eaux peu profondes au large du delta du Mackenzie : les termes du frottement contre le fond et du déferlement lié à la profondeur. Nous utilisons des observations du vent et des vagues, le modèle d'avant-garde SWAN (Simulating Waves Nearshore) et des données de vent et de vagues réanalysées. Les deux périodes d'observations sont une expérience sur le terrain réalisée en août 2008, au cours de laquelle des données de terrain ont été recueillies, et une tempête arctique lors de laquelle des mesures faites par bouée du 4 au 6 août 1991 ont été enregistrées. Nous analysons les processus dévolution du vent et des vagues durant ces deux périodes, et comparons avec le vent et les vagues observées. Nos analyses montrent que le frottement contre le fond est le processus physique en eaux peu profondes le plus important durant l'expérience sur le terrain d'août 2008, alors que le déferlement lié à la profondeur est le processus physique en eaux peu profondes dominant pendant la tempête arctique du 4 au 6 août 1991, en combinaison avec les effets du frottement contre le fond. Nous nous servons du modèle de vagues SWAN pour étudier les processus physiques en eaux peu profondes durant ces deux périodes d'observations. Les résultats des simulations indiquent que le modèle peut donner des résultats raisonnables, avec un coefficient de Collins approprié de 0,006 et un paramètre de déferlement de 0,55 pour représenter la physique du frottement contre le fond et du déferlement lié à la profondeur, respectivement.  相似文献   

Effects of topography on lofting gravity flows: Implications for the deposition of deep-water massive sands     

Christopher J. Stevenson  Jeff Peakall 《Marine and Petroleum Geology》2010

Hyperpycnal flows are generated in the marine environment by sediment-laden fresh water discharge into the ocean. They frequently form at river mouths and are also generated in proximal ice-melting settings and are thought to be responsible for transporting a large proportion of suspended river sediment onto and off the continental shelf. Hyperpycnal flows are an example of gravity currents that display reversing buoyancy. This phenomenon is generated by the fresh water interstitial fluid being less dense than that of the ambient seawater. Thus after sufficient particles are sedimented the flow can become positively buoyant and loft, forming a rising plume. Here we present results from physical scale-modelling experiments of lofting gravity currents upon interaction with topography. Topography, in the form of a vertical obstacle, triggered a localised lofting zone on its upstream side. This lofting zone was maintained in a fixed position until the bulk density of the flow had reduced enough to allow lofting along its entire length. The obstructed lofting zone is associated with a sharp increase in deposit thickness. By inference these experimentally established lofting dynamics are applied to improve understanding of the potential for hyperpycnal flows to deposit deep-water massive sands. This study provides a depositional mechanism by which large volumes of sand can be deposited in the absence of traction and the fines removed, leaving thick deposits of structureless sand with a low percentage of mud. This conceptual model for the first time provides a framework by which the geometries of certain deep-water massive sands may be predicted within specific depositional and basinal settings. This is crucial to our understanding of massive sand deposits in modern and ancient turbiditic systems and in the commercial evaluation of hydrocarbon potential of such sedimentary successions.  相似文献   

1：50000数据库的更新服务数据库系统设计与实现     

张元杰  商瑶玲  段松鹤  查祝华 《测绘软科学研究》2012,(1):27-31

1：50000数据库的更新工程数据库服务系统是以1：50000数据库更新成果为基础．建立了一个基于B／S结构的服务系统,满足更新数据快速发布、浏览、应急服务等需求。本文介绍了陔系统的设计思想、系统总体架构、数据库设计与建库、软件功能设计与实现,为其他地理信息数据系统建设提供借豁。  相似文献   

The Importance of Geography in Education II     

《The Journal of geography》2012,111(5):206-213

Abstract

The concept of scale is fundamental to geography, yet the definitions for “scale” and related spatial terms can be confusing to those working in other spatial science disciplines. This is particularly true in the emerging multidisciplinary world of integrated remote sensing and geographic information systems, or IGIS's, where data of different types and at various spatial and temporal scales are combined to support complex space-time data analyses. Without a basic lexicon of accepted scale terms, working within an IGIS can breed confusion in the interpretation of data and the models that result from an IGIS construct. This paper provides some terminologies of scale that can be used as a framework for a multidisciplinary lexicon of accepted scaling terms and describes their relationships to an IGIS. It also illustrates how scaling terms can be potentially misunder stood when applied to geographic techniques that are used in disciplines related to geography.  相似文献   

Use of localized descriptive statistics for exploring the spatial pattern changes of bird species richness at multiple scales     

Zhihai MaBenjamin Zuckerberg  William F. PorterLianjun Zhang 《Applied geography (Sevenoaks, England)》2012,32(2):185-194

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