南黄海表层沉积物天然湿容重和含水量的分布及其与粒度之间的关系   总被引：2，自引：0，他引：2  

徐善民 《海洋科学》1991,15(3):38-41

本文论述了南黄海表层沉积物天然湿容重和含水量的分布,并利用回归分析的方法讨论了容重和含水量与粒度之间的关系。结果表明,容重和含水量与粘土粒级相关性最好,容重与粘土粒级含量(相似文献   

Generation of random waves in time-dependent extended mild-slope equations using a source function method     

Gunwoo Kim  Changhoon Lee  Kyung-Duck Suh   《Ocean Engineering》2006,33(14-15):2047-2066

We develop techniques of numerical wave generation in the time-dependent extended mild-slope equations of Suh et al. [1997. Time-dependent equations for wave propagation on rapidly varying topography. Coastal Engineering 32, 91–117] and Lee et al. [2003. Extended mild-slope equation for random waves. Coastal Engineering 48, 277–287] for random waves using a source function method. Numerical results for both regular and irregular waves in one and two horizontal dimensions show that the wave heights and the frequency spectra are properly reproduced. The waves that pass through the wave generation region do not cause any numerical disturbances, showing usefulness of the source function method in avoiding re-reflection problems at the offshore boundary.  相似文献   

用包埋脱水法冰冻保存海洋饵料金藻   总被引：4，自引：0，他引：4  

王起华  李贺  张恩栋  高艳萍  李大鹏 《海洋与湖沼》2005,36(2):172-178

用包埋脱水法冰冻保存绿色巴夫藻(Pavlova uiridis)、湛江等鞭金藻(Isochrysis zhanjiangensis)和球等鞭金藻(Isochrysis galbana 3011)等三种海洋饵料金藻，探讨了脱水速率、胶球含水量以及化冻后恢复方法对冰冻保存存活率的影响。结果表明，三种藻都在-0．9％含水量／h的平均脱水速率下获得最高存活率：各种藻在冰冻前的胶球最佳含水量不同，绿色巴夫藻为35％，湛江等鞭金藻和球等鞭金藻都为30％。化冻后，含绿色巴夫藻的胶球在培养基中22℃暗放置48h存活率最高；另两种藻在相对湿度为75％的气相中22℃暗放置12h存活率最高。在本实验条件下，绿色巴夫藻、湛江等鞭金藻和球等鞭金藻的冰冻保存的存活率可分别达到74％、15％和17％。  相似文献   

E1 Nio phenomenon in simple ocean data assimilation data     

GUI Maochang  *  WU Lingjuan  . Institute of Oceanology  Chinese Academy of Sciences  Qingdao  China. Laboratory of Numerical Modeling for Atmospheric Sciences  Geophysical Fluid Dynamics  Institute of Atmospheric Physics  Chine-se Academy of Sciences  Beijing  China. Graduate School  Chinese Academy of Sciences  Beijing  China 《海洋学报(英文版)》2005,(4)

1 IntroductionIt is well known that interaction between the trop-ical ocean and atmosphere produces the largest inter-annual climate signal, El Nino-Southern Oscillation(ENSO). In past decades many efforts have been madein understanding and predicting ENSO: such as the hy-pothesis of Bjerknes (1969) that ENSO arises as aself-sustained cycle in which SSTA in the Pacific O-cean causes the trade winds to strengthen or slackenand that this in turn drives the ocean circulation changesthat …  相似文献   

Numerical and experimental study on hydrodynamic interaction of side-by-side moored multiple vessels   总被引：2，自引：0，他引：2  

S.Y. Hong  J.H. Kim  S.K. Cho  Y.R. Choi  Y.S. Kim 《Ocean Engineering》2005,32(7):783-801

This paper aims to investigate the basic interaction characteristics of side-by-side moored vessels both numerically and experimentally. A higher-order boundary element method (HOBEM) combined with generalized mode approach is applied to analysis of motion and drift force of side-by-side moored multiple vessels (LNG FPSO, LNGC and shuttle tankers). Model tests were carried out for the same floating bodies investigated in the numerical study in regular and irregular waves. Global and local motion responses and drift forces of three vessels are compared with those of calculations. Discussions is highlighted on applicability of numerical method to prediction of sophisticated multi-body interaction problem of which motion behavior is very important to analysis of mooring dynamics of deep sea floating bodies.  相似文献   

鱼粉脂肪酸组成的分析研究   总被引：7，自引：1，他引：7  

宋永康  林虬  陈人弼 《台湾海峡》2004,23(1):88-93

本文应用气相色谱对水产饲料的主要原料——— 4类进口鱼粉的脂肪酸组成进行分析 ,结果表明 :①鱼粉中主要脂肪酸含量SFA为C1 6∶0、C1 8∶0 ,MUFA为C1 8∶1、C1 6∶1 ,PUFA为EPA和DHA .② 4类鱼粉中 ,美国、新西兰、俄罗斯的鱼粉MUFA含量较为接近 ,都在 4 0 %左右 ,但新西兰鱼粉的C1 8∶1含量较美国鱼粉高 ,其平均值分别为 2 50 %和 1 9.53% ,而C 2 0∶1、C2 2∶1 ,则比美国低一些 ,俄罗斯鱼粉的含量居两者之间 .智利鱼粉的MUFA比前 3种鱼粉低 ,只有 30 %左右 .③ 4类鱼粉中新西兰鱼粉的PUFA最低 ,它们的EPA与DHA的比值为 :美国鱼粉接近 1∶1 ,新西兰鱼粉为1∶1 .5～ 1∶3.2 ,俄罗斯鱼粉为 1∶1 .2～ 1∶1 .4 ,智利鱼粉为 1∶2左右 ,④智利鱼粉的C2 2∶5n 3明显高于其它 3类鱼粉 ,而C2 0∶1、和C2 2∶1则明显低于其它 3类鱼粉  相似文献   

基于雷达海冰图像互相关的冰漂流场测量   总被引：5，自引：2，他引：5       下载免费PDF全文

孙鹤泉  孙延维  王平让 《海洋学报》2003,25(4):135-141

我国的渤海和黄海北部在每年冬季都出现不同程度的冰情,它直接影响结冰海区的石油平台、船舶以及港口等设施的正常作业,对海冰的观测与预报随着上述海区的开发利用越发显得重要,利用航海雷达连续准确地跟踪海冰漂移运动轨迹,是当今观测、调查、研究冰漂流移动规律的有效方法之一,我国的科研人员利用雷达成像技术对渤海的冰情进行了长期的雷达海冰观测、研究,在由雷达海冰图像对海冰的物理特征的识别、分类以及冰漂流场测量方面取得了一些进展[1-4]。  相似文献   

Spatial patterns and environmental risks of ringnet fishing along the Kenyan coast     

P Thoya  S Pérez-Jorge  GM Okemwa  H Mwamlavya  A Tuda  N Wambiji 《African Journal of Marine Science》2020,42(1):23-33

Ringnet fishing began in the early 20th century and is practised worldwide, mainly to target nearshore pelagic species. The method was introduced to Kenya’s coastal waters by migrant fishers from Tanzania. However, the impacts of this fishing gear remain poorly assessed. We assessed the spatial distribution of ringnet fishing effort and its possible effects on ecosystem components, such as coral reefs, marine megafauna and marine protected areas, on the south coast of Kenya. We tracked 89 ringnet fishing trips made from December 2015 to January 2016 and used spatial multicriteria analysis to determine hotspots of possible environmental risks. The results showed that habitat type and bathymetric profile influenced the spatial distribution of ringnet fishing effort. Mixed seagrass and coral habitats had the highest concentration of the effort. Most of the habitats in the study area were moderately exposed to the impacts of the ringnet fishery. The study identifies high-risk areas that require spatial measures to minimise possible environmental risks of the gear both to habitats and to endangered sea turtles.  相似文献   

A Forced System of Two Cylinders with Various Spacings   总被引：3，自引：0，他引：3  

邹建锋  任安禄邓见 《中国海洋工程》2004,18(3):391-402

The spectrum characteristics and wake structures for a circular cylinder oscillating in a wake are investigated by use of the currently modified virtual boundary method. A forced system of two cylinders with a small spacing ( the downstream one is made to oscillate in the transverse direction) is studied and interesting flow characteristics are observed. A vortex switch and the change of vortex modes (between 2S mode and 2P mode) are observed in the “lock-in“ region. Vortex bands are formed and lost with the increasing excitation frequency. Information concerning saddle points in the flow field is obtained for different excitation frequencies. For a forced system of two cylinders with a large spacing, the upstream cylinder sheds vortexes because there is no downstream cylinder oscillating in the wake. No distinct “lock-in“ response is found for the downstream cylinder.  相似文献   

The optimum control of thruster system for dynamically positioned vessels     

C. C. Liang  W. H. Cheng 《Ocean Engineering》2004,31(1):97-110

An offshore vessel with a dynamic positioning system (DP system) needs fast response to produce thrust to counteract the environmental forces acting on it for the purpose of maintaining its position and heading as close as possible to the working position. Therefore, quick and effective modulation of the thrust is the problem to determine the thrust and the rotation angle of the thruster devices of the ship. This paper presents an effective optimum control for a thruster system, using the sequential quadratic method to achieve economical and effective modulation of the thrust and the direction of the thruster. An optimum control study of a 2280 tons DP coring vessel with five rotary azimuth thruster marine positioning is studied in detail, which can quickly and exactly estimate the thrusts and angles of direction of all the thrusters. The results can provide a valuable thruster system for a dynamically positioned vessel.  相似文献