首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
大容量海水采水器的研制   总被引:1,自引:0,他引:1  
留籍援  黄财宾  陈坚 《台湾海峡》2006,25(1):139-142
介绍一种实用新型的采水器,该采水器具有全新的开闭装置及密封结构.文章对采水器的构造、工作原理及特点进行了有益的探讨。  相似文献   

2.
厦门海域浅水三维潮流场动力学模型   总被引:2,自引:0,他引:2       下载免费PDF全文
基于Casulli的三维浅水模型,改进浅滩处理方法,并入简化的紊流闭合模型,形成完整的海洋动力学基本方程组,改进了紊流闭合模型的求解方法,动力学模拟结果与实测结果符合良好,海域中大量浅滩的干出与淹没的面积和位置与实际情况吻合良好.本模型是厦门海域海洋动力学理论研究中第一个完全的三维斜压潮流场模型,全部程序用FORTRAN语言独立开发和编写.  相似文献   

3.
Three-dimensional hydrodynamic model of Xiamen waters   总被引:3,自引:0,他引:3  
Abstract-A semi-implicit and Eulerian-Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-momentturbulence closure model and transport equations of salinity and temperature. The simulation for flood-ing and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on exten-sive survey data, water level elevation, temperature and salinity field along the eastern open boundaryand at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed resultsshow good agreement with the measured data, reproduce flooding, emergence of large and complexmudflat region.  相似文献   

4.
StudiesonprimaryproductivitymodelinshallowmixedwatersMaoXinghua,ZhuMingyuan,YangXiaolong,HaoYawei,JohnCullen(ReceivedOctober2...  相似文献   

5.
A sampler which permits concentration of both particulate and dissolved radionuclides from large volumes of ocean and freshwater has been developed and tested. The water sample passes through a filtration section for particle removal, then through a sorption section where the radionuclides of interest are removed on sorption or ion exchange beds. Components of the sampler which contact the water are of polyvinyl chloride construction, and flow rates of about 40 l./min are employed. This sampler has been successfully employed in concentrating some twenty radionuclides from ocean and fresh waters.  相似文献   

6.
Estuarine, Coastal and Shelf Science has throughout its history considered a diverse range of habitats including estuaries and fjords, brackish water and lagoons, as well as coastal marine systems. Its articles have reflected recent trends and developments within the estuarine and coastal fields and this includes the changing use of well-accepted terms. The term “transitional waters” first came to prominence in 2000 with the publication of the Water Framework Directive of the European Communities [European Communities, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. Official Journal of the European Communities 43 (L327), 75 pp.], where “transitional waters” are defined as “bodies of surface water in the vicinity of river mouths which are partially saline in character as a result of their proximity to coastal waters but which are substantially influenced by freshwater flows”. The inclusion of the term transitional waters in our own aims and scope reflects the evolution of language in this subject area, encompassing tidal estuaries and non-tidal brackish water lagoons. This article reflects on some of the difficulties posed by the use of the term and its attempts to be inclusive by incorporating fjords, fjards, river mouths, deltas, rias and lagoons as well as the more classical estuaries. It also discusses the problems of including in the term river mouths discharging either into predominantly brackish areas such as the Baltic Sea, or into freshwater-poor areas bordering the Mediterranean.  相似文献   

7.
遥感测量海水表面温度(SST)需用海表面以下实测温度资料加以校正,由于长时间大范围进行海洋表层海水垂向温度剖面野外观测非常困难,建立经有限资料验证的数值模型十分重要。文章基于美国加利福尼亚湾3组船载光学实验的气象及海温资料,考虑太阳热辐射作用与海表面冷温层效应,建立了一个海表下20m深度范围内水温剖面演变的数值模型。通过冷温层计算合理加密了表层网格,使数值模型更准确地估计海表散热作用。计算结果与野外实测海温资料对比显示,海表剖面测试仪(SkinDeEP)未能准确定位和捕捉海表冷温层,实验方法有待改进。整合模型能准确描述海温剖面的演变趋势,在近海表20cm深度内,特别是与遥感SST相关的近海表1cm深度内,模拟结果优于无本皮肤层模型的计算结果。  相似文献   

8.
A new, automatic hydrothermal fluid sampler using a shape-memory alloy   总被引:2,自引:0,他引:2  
A new hydrothermal fluid sampler has been developed to provide more maneuverability in underwater operation. The sampler characteristically employs a shape-memory alloy, which senses high temperature and actuates the suction mechanism. A shape-memory alloy is also used to switch the intake valve of the sampler, the intention being to avoid missampling when the inlet is in low temperature water. Prototype samplers were designed to collect the fluids hotter than 80°C. Test sampling was performed at hydrothermal vents (1372–1374 m deep) in the submarine volcano, Suiyo Seamount, Izu-Bonin Arc, northwestern Pacific. Observed fluid temperature was between 138 and 298°C, while the ambient seawater temperature was 3.1°C. Each prototype collected about 100 ml fluid as designed. The magnesium concentration in the samples indicated a seawater content of 47.5–90.8%, which indicates the entrainment of ambient seawater. Microscopic observatinn revealed the occurrence of microorganisms in the sample fluids at a population density of 105 to 106 cells ml−1, which is 2–3 orders of magnitude higher than those in seawater at that depth. The use of the newly developed fluid sampler will greatly facilitate the collection of vent-associated microorganisms, which are of potential biological and biotechnological interest.  相似文献   

9.
可浮动自锁式深海气密采水器的研制   总被引:1,自引:0,他引:1  
深海海水中气体的含量可以在一定程度上标识深海资源蕴藏量,因而实现对深海海水的气密采样意义重大.为此设计了一种可浮动的自锁装置,并采用压力自适应平衡原理,实现了对深海海水的气密采样.实验室和海上试验结果均表明深海气密采水器在装上可浮动自锁装置后耐压能力和气密性都得到了有效的提高,对初始压强为1.208 MPa的N2气保压2 h,压力损失不到1.2%,并成功地实现了对960 m深的海水样品的气密采样.此样品中CH4浓度为5.44 nmol/dm^3,CO2浓度为140.6nmol/dm^3.该可浮动自锁式深海气密采水器的研制为深海资源勘探分析提供了必要的技术支持.  相似文献   

10.
The hydrostatic energy of high-pressure seawater is a renewable and green energy source for ocean exploration and have been used to replace underwater electrical energy transmission through the cable and underwater battery pack to power seafloor equipment. The advantage of the energy supply method is the cost-effective and the robustness. In the paper, the energy performance of the existing hydrostatic seafloor sediment samplers powered by seawater hydrostatic energy are modelled and analyzed and compared. In view of the common shortcoming of existing technology, a novel hydrostatic seafloor sediment sampler is proposed. The model of energy conversion of the new sampler is built, and its energy performance is obtained. The analysis results indicate that the energy conversion efficiency of the novel sediment sampler is much higher than the existing ones, which means that the new sampler can collect much longer sample with the limited amount of hydrostatic energy. The seawater hydrostatic energy conversion system of the new sampler can also be used to power other seafloor equipment.  相似文献   

11.
南海表层水中的溶解态Cu,Pb, Zn,Cd   总被引:9,自引:0,他引:9  
于1998年“南海海洋环境调查”外业工作期间在南海的各个站位,按照严格的防沾污措施采集了106个表层海水样品.采用溶剂萃取-石墨炉原子吸收法对样品中的痕量重金属Cu,Pb,Zn,Cd含量进行了分析测试.测得各重金属的平均值如下:Cu 0.100 μg/dm3,Pb 0.060μg/dm3,Zn 0.086 μg/dm3,Cd 0.007μg/dm3,接近世界大洋水的浓度水平.各重金属的空间分布呈现出海区周边含量高于中央,浓度有自近岸向远海逐渐减小的趋势.相关分析的结果表明各重金属夏季相关性优于冬季,Cu与Cd存在良好的正相关关系,并且首次在南海表层水发现Cu,Cd与营养盐的相关关系.将重金属浓度值作数理统计分析,得到它们在南海的基线值.  相似文献   

12.
Mercury speciation and its distribution in surface and deep waters of the Mediterranean Sea were studied during two oceanographic cruises on board the Italian research vessel URANIA in summer 2003 and spring 2004 as part of the Med Oceaneor and MERCYMS projects. The study included deep water profiles of dissolved gaseous Hg (DGM), reactive Hg (RHg), total Hg (THg), monomethyl Hg (MeHg) and dimethyl Hg (DMeHg) in open ocean waters. Average concentrations of measured Hg species were characterized by seasonal and spatial variations. Overall average THg concentrations ranged between 0.41 and 2.65 pM (1.32 ± 0.48 pM) and were comparable to those obtained in previous studies of the Mediterranean Sea. A significant fraction of Hg was present as “reactive” Hg (average 0.33 ± 0.32 pM). Dissolved gaseous Hg (DGM), which consists mainly of Hg0, represents a considerable proportion of THg (average 20%, 0.23 ± 0.11 pM). The portion of DGM typically increased towards the bottom, especially in areas with strong tectonic activity (Alboran Sea, Strait of Sicily, Tyrrhenian Sea), indicating its geotectonic origin. No dimethyl Hg was found in surface waters down to the depth of 40 m. Below this depth, its average concentration was 2.67 ± 2.9 fM. Dissolved fractions of total Hg and MeHg were measured in filtered water samples and were 0.68 ± 0.43 pM and 0.29 ± 0.17 pM for THg and MeHg respectively. The fraction of Hg as MeHg was in average 43%, which is relatively high compared to other ocean environments. The concentrations reported in this study are among the lowest found in marine environments and the quality of analytical methods are of key importance. Speciation of Hg in sea water is of crucial importance as THg concentrations alone do not give adequate data for understanding Hg sources and cycling in marine environments. For example, photoinduced transformations are important for the presence of reactive and elemental mercury in the surface layers, biologically mediated reactions are important for the production/degradation of MeHg and DGM in the photic zones of the water column, and the data for DGM in deep sea indicate the natural sources of Hg in geotectonicaly active areas of the Mediterranean Sea.  相似文献   

13.
海底麻坑是由地层中流体向海底快速喷发或缓慢渗漏所形成的一种凹陷地貌,对其形态及成因机理进行深入研究具有重要意义.本研究基于高分辨率多波束地形、侧扫声纳、浅地层剖面及多道地震探测数据,对舟山群岛东部青浜岛海域发育的麻坑及其微地貌进行研究,分析表明:研究区发育有3个大型麻坑,并受到NE—SW向底流的改造而出现不同程度沿此方...  相似文献   

14.
The understanding of the distribution of trace heavy metals in the world ocean has greatlyimProved in the past decades. But most of the data are of vertical profiles of certain stations(Bruland, l980; Paul et al., l992; RObert et al., l990) and large--scale study of temporaland spatial variability of trace heaVy metals in the ocean is rather few. In fact, affected by ver-tical mixing by upwelling or convection, biogenic removal, atmospheric fallout and continentalinput frorn rivers, the dist…  相似文献   

15.
中国近岸海域潜在性富营养化程度的评价   总被引:105,自引:6,他引:105  
根据近岸海域的富营养化普遍受营养盐限制的特征,提出了潜在性经的概念,并在此 提出了一种新的富营养化分级标准及相应的评价模式,运用该模式分别评价了厦门海域及中国近海的富养化程度。结果表明,厦门东海域敞 于贫营养水平,而西海域则为磷限制潜在性营养水平;与厦门西海域相近,中国近海主要河口、海湾总体上处于磷限制或磷中等限制潜在性富营养水平。  相似文献   

16.
17.
浅海新型FPSO-IQFP多点系泊系统设计研究   总被引:2,自引:0,他引:2  
王天英 《海洋工程》2014,32(3):89-95
海上油气生产要求FPSO具有低幅运动的特性,因此系泊系统性能的优劣直接影响生产作业的效率和安全。针对新概念FPSO-IQFP(圆角倒棱台形FPSO)的浮体特点和边际油田经济性开发的需要,设计一套经济有效的多点系泊系统。首先,将钢制悬链线系泊系统和聚酯纤维张紧式系泊系统作为备选方案,根据定常力计算结果并参照工程经验,给出两种系泊系统的初始设计方案,并进行二者的静特性分析,探讨系泊参数对系泊系统受力和位移的影响规律;在此基础上,结合时域计算结果,确定系泊系统的优化设计方案;最后,给出系泊系统的回复力和浮体位移之间的关系曲线,并在静力范围内比较两种系泊系统的优劣性。静力分析结果初步验证,较之悬链线系泊系统,张紧式系泊系统用于浅水作业的IQFP上更具优越性。  相似文献   

18.
根据2013年11月、2014年2月、5月、9月在南麂列岛国家海洋自然保护区海域进行生物资源调查所获得的资料,分析了南麂列岛海域蟹类种类组成、优势种、生物多样性等群落结构特征,并定量分析了群落结构与水文环境因子之间的关系。结果表明,周年4个季度月调查共鉴定出蟹类21种,隶属7科、12属,其中优势种为三疣梭子蟹(Portunus trituberculatus)、日本蟳(Charybdis bimaculata)和双斑蟳(Charybdis bimaculata)3种。不同季节的蟹类种类组成差异较大,而优势种类组成变化较少,其中,以秋季的蟹类种类数最多,冬季最少。从不同水深区域的渔获种类分布趋势来看,蟹类种类以20~30 m水深带较多,30~40 m水深带较少。夏季多样性指数低于其他季节,以水深来看,多样性指数在10~20 m水深带较高,30~40 m水深带较低,蟹类多样性指数与水深呈反比。根据冗余分析认为,水深、水温和盐度是影响调查海域蟹类种类组成和群落结构特征的主要环境因子。  相似文献   

19.
The present study investigates the drift of two-dimensional floating surface films by both deep and shallow water waves in the laboratory. The focus is on the observations and measurements on the drift behavior and to clarify some outstanding issues. Thin polyethylene sheets with reflective markers were attached to simulate the inextensible surface films. Upon the initiation of a wave train, two infrared cameras recorded continuously the instantaneous position of the markers at 50 Hz. The temporal variation of the drift velocity was then determined by processing the recorded data. In all experiments, the drift velocity increased quickly in the beginning and reached a quasi-steady mean value. The magnitude of the surface drift typically increased with the longitudinal length of the polyethylene sheet until the sheet length was approximately the same as the wavelength. Lengthening the sheet length further did not lead to significant changes in the drift velocity. Under the shallow water condition, the wave-induced drift velocity increased linearly with the Ursell number and with a lower water depth.  相似文献   

20.
A brief review is made on the theory of the Lagrangian residual circulation and inter-tidal transports in a convectively weakly nonlinear system. In the review the emphasis is put on the systematical development of the theory and its weakness of convectively weakly nonlinear approximation. The fundamentals of a Lagrangian tidally-averaged theory on circulation with inter-tidal transport processes have been proposed for a general nonlinear coastal/estuarine system. The Lagrangian residual velocity is strictly de- fined, and it has been verified to be able to embody the velocity field of circulation. A new concept of the concentration for inter- tidal transport processes is presented. The concentration describing the inter-tidal transport processes should be a "Lagrangian inter-tidal concentration" defined and named, but not the Eulcrian tidally-averaged concentration used traditionally. The circulation described here contains a set of infinite temporal-spatial fields of velocity/concentration, each of which corresponds to a specific value of tidal phases varying continuously over one tidal cycle. When the convectively weakly nonlinear condition( with a smaller order of eddy diffusion and sources) is approximately satisfied, a set of infinite temporal-spatial fields of velocity/concentration can be reduced to a single one.. the mass transport velocity/the Eulerian tidally averaged concentration as exhibited traditionally.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号