Analytic Solution of Interaction Between Surface Waves and Floating Elastic Plates with Elastic End-Restraints     

赵存宝张嘉钟  邢海燕黄文虎 《中国海洋工程》2007,21(1):23-38

Based on the dynamic theories of water waves and Mindlin plates,the analytic solution of interaction between surface waves and two-dimensional floating elastic plates with edge-restraint is constructed by use of the Wiener-Hopf technique.Firstly,without regard for elastic edge restraint,the wave-induced responses of elastic floating plate analyzed by the present method are in good agreement with the results from literature and experimental results.Therefore,it can be shown that the present method is valid.Secondly,three end-restraint cases(i.e.,the left-end elastic restraints,the both-end elastic restraints,and the right-end elastic restraints)are proposed to reduce the vibration of floating plates,in which the spring is used to connect the sea bottom and the floating plate's left(or right)edge.The relations between the spring stiffness and the parameters of wave-induced responses of floating plates are discussed.Moreover,the effective method to reduce the vibration of floating elastic plates can be obtained through comparison.  相似文献   

Lower Cd/P ratio in settling particles than in surface seawater in the Okinawa Trough     

Kazuo Abe  Kazuo Iseki  Kazumaro Okamura  Yoko Kiyomoto 《Journal of Oceanography》2006,62(5):745-752

The characteristics of the ratios between cadmium (Cd) and phosphorus (P) in settling particles collected from the Okinawa Trough in the East China Sea were examined using a sediment trap, moored at a depth of 811 m for one year. The Cd/P ratios varied within a narrow range throughout the year, in spite of the large seasonal change in the total dry mass, Cd, and P fluxes. The average Cd/P ratio of settling particles was 0.062 (nmol/μmol), which was obviously lower than that of surface seawater around the study site (0.16). This lower ratio in the Okinawa Trough particles collected using the 811 m-moored trap certainly reflected the mixture of biologically produced organic matter around the study site and other components that were mainly transported as lateral flux from the shelf edge and slope area of the East China Sea.  相似文献   

Effect of enriched rotifers on growth, survival, and composition of larval Atlantic cod (Gadus morhua)   总被引：1，自引：0，他引：1  

Park  Heum Gi; Puvanendran  Velmurugu; Kellett  Anne; Parrish  Christopher C.; Brown  Joseph A. 《ICES Journal of Marine Science》2006,63(2):285-295

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Colonization, succession, and nutrition of macrobenthic assemblages in a restored wetland at Tijuana Estuary, California     

Serena M. Moseman  Lisa A. Levin  Carolyn Currin  Charlotte Forder   《Estuarine, Coastal and Shelf Science》2004,60(4):755-770

Modes of colonization, the successional trajectory, and trophic recovery of a macrofaunal community were analyzed over 19 months in the Friendship marsh, a 20-acre restored wetland in Tijuana Estuary, California. Traditional techniques for quantifying macrofaunal communities were combined with emerging stable isotopic approaches for evaluation of trophic recovery, making comparisons with a nearby natural Spartina foliosa habitat. Life history-based predictions successfully identified major colonization modes, although most taxa employed a variety of tactics for colonizing the restored marsh. The presence of S. foliosa did not seem to affect macrofaunal colonization or succession at the scale of this study. However, soil organic matter content in the restored marsh was positively correlated with insect densities, and high initial salinities may have limited the success of early colonists. Total macrofaunal densities recovered to natural marsh levels after 14 months and diversity, measured as species richness and the Shannon index (H′), was comparable to the natural marsh by 19 months. Some compositional disparities between the natural and created communities persisted after 19 months, including lower percentages of surface-feeding polychaetes (Polydora spp.) and higher percentages of dipteran insects and turbellarians in the Friendship marsh. As surficial structural similarity of infaunal communities between the Friendship and natural habitat was achieved, isotopic analyses revealed a simultaneous trajectory towards recovery of trophic structure. Enriched δ¹³C signatures of benthic microalgae and infauna, observed in the restored marsh shortly after establishment compared to natural Spartina habitat, recovered after 19 months. However, the depletion in δ¹⁵N signatures of macrofauna in the Friendship marsh indicated consumption of microalgae, particularly nitrogen-fixing cyanobacteria, while macroalgae and Spartina made a larger contribution to macrofaunal diets in the natural habitat. Future successional studies must continue to develop and employ novel combinations of techniques for evaluating structural and functional recovery of disturbed and created habitats.  相似文献   

2001-2002年天目湖(沙河水库)浮游植物的生态学研究   总被引：7，自引：0，他引：7  

张运林  陈伟民  周万平  杨顶田  江晶 《海洋湖沼通报》2006,(2):31-37

2001年6月~2002年5月,对天目湖进行的浮游植物周年调查表明,天目湖共有浮游植物7门75属,其中年平均丰度为5026.20×104个/L,以蓝藻为主,占总丰度的54.45%;而年平均生物量为(15.364±9.103)mg/L,其中硅藻居首位,为6.634 mg/L,占浮游植物年平均生物量的43.18%;其周年变化是丰度和生物量最高值均出现在5月,丰度在5月和9月出现2个峰值,而生物量则在5、7、10月出现3个峰值。浮游植物丰度从大坝处1#点到河流入湖口的9#、10#点变化不明显但略有增加,而生物量则呈明显增加。通过对水温、透明度、营养盐与浮游植物丰度和生物量的线性回归分析发现,浮游植物丰度、生物量与水温、TP存在显著的正相关,而与N/P比、透明度存在显著性负相关,与TN相关性不是很明显。  相似文献   

海底孔压对波浪响应试验研究及数值模拟   总被引：6，自引：1，他引：6  

刘涛  冯秀丽  林霖 《海洋学报》2006,28(3):173-176

孔隙水压力在海底土尤其在砂性海床中扮演着一个非常重要的角色.波浪的周期性加载作用,在砂土及粉土中产生超静孔隙水压力,其幅值大小是海床发生液化破坏的控制因素.在海上工程的历次调查中发现孔压引起许多液化破坏现象,如粉土海床的塌陷、凹坑、坡度较大处的粉砂流及构筑物基础周围的过量冲刷造成石油管架下沉等等,因此研究海床中孔压对波浪的响应具有重要的理论意义和实践意义.  相似文献   

Nonlinear dynamic analysis of deep water risers     

V.Hachemi Safai 《Applied Ocean Research》1983,5(4):215-225

The paper presents a theoretical and numerical approach to the dynamical behaviour of risers in deep water which takes into account two types of nonlinearity; that due to viscous drag forces and that due to the large displacements of the riser when submitted to strong axial loads. As the second nonlinearity may have a significant influence upon the behaviour of risers in deep water, a method for automatically updating the structural geometry during the dynamic analysis is given. A computer programme has been written for this purpose.  相似文献   

基于RS和GIS的唐山沿海地区湿地结构动态监测     

汪高明  邱若峰  SUN Xiaogong 《海洋湖沼通报》2007,(3):35-40

利用历史资料和Landsat TM卫星遥感图像,研究了唐山市沿海地区湿地结构自上世纪80年代以来的演变特征,着重对1987~2004年陡河——滦河之间的湿地结构类型进行了识别,绘制了不同时期的湿地面积解译图。利用Mapinfo制图软件计算出两个时期的面积转化矩阵,对该区主要湿地类型浅海水域、滩涂、芦苇沼泽、水稻田、养殖场、盐田等湿地的面积进行了年份比较,从而分析得出唐山市沿海湿地结构从80年代至今以来破碎化加重,应该加强湿地结构的动态监测。  相似文献   

动态基准实时测量系统的开发与应用   总被引：3，自引：0，他引：3  

卫建东  徐忠阳  张良琚 《海洋测绘》2005,25(1):31-35

介绍了动态基准实时测量系统的硬件组成、站点上全站仪棱镜组合安装与检测方法、系统软件的开发及特点，最后对系统在广州地铁某地铁站结构变形自动监测中的应用情况进行了阐述。通过实际应用表明该系统能应用在自动化、高精度的变形监测领域。  相似文献   

大气污染物质SO₂对雾水酸度的控制作用     

宋金明  李鹏程  詹滨秋 《海洋科学》1994,18(5):44-49

主要研究了青岛大气污染物质ＳＯ２对雾水酸度的控制作用，用实测结果统计得到雾得水ＰＨ值与Ｃｓｏ２的经验关系式，青岛、烟台等地雾水ｐＨ值与计算值吻合一致，表明统计关系的合理性。通过对青岛雾水中ＳＯ２清除率的估算，说明在青岛雾期，人为污染物质所占比值越高，其污染物质沉降百分率也越高，存留在大气雾中百分率就愈低。  相似文献