Analysis of Dynamic Characteristics of Submarine Free Spanning Pipelines by Complex Damping Method   总被引：2，自引：0，他引：2  

傅强郭海燕  杨新华 《中国海洋工程》2004,18(3):485-491

Considering the effect of the internal flowing fluid and the external marine environmental condition, the differential equation for the vortex-induced vibration (V1V) of the free spanning pipeline is derived and is discretized by the Hermit interpolation function. The free vibration equation with the damping term is solved by the complex damping method for the natural frequency, and then the effect of fluid damping on the natural frequency of the free spanning pipeline is analyzed.The results show that fluid damping has a significant influence on the damped natural frequency of the free spanning pipeline in the lock-in state, while it has little influence when the pipeline is out of the lock-in state. In the meantime,the change of the free span length has the same effect on the damped natural frequency and the undamped natural frequency.  相似文献   

全球船舶压载水管理项目在我国启动     

复林 《海洋信息》2001,(1)

为了防止全球船舶压舱水中的有害水生物在海洋中传播,危害海洋生态环境,造成海洋污染,2000年9月20日～21日,我国召开了关于制定船舶压载水管理国家项目工作计划和宣传项目研讨会。据悉,国际海事组织近年来一直在努力采取措施,制订有关法规,并将在2002年召开大会予以通过。届时,关于船舶压载水的管理规定将成为全球强制性要求。  相似文献   

盐碱水NaCl浓度和碱度对银鲫(Carassius auratus gibelio)幼鱼毒性的初步研究   总被引：2，自引：0，他引：2  

郑伟刚  张兆琪  张美昭  董双林 《中国海洋大学学报(自然科学版)》2001,31(4):513-517

通过对银鲫(Carassiusauratusgibelio)幼鱼(L=3.56±0.28cm)的NaCl浓度(pH=8.80±0.10)及碱度(pH=8.84±0.26)的急性毒性试验，用概率单位法求得其24，48，96h的半致死浓度(LC50值)NaCl浓度分别为11.53、10.77、8.58g/L；碱度分别为98.74、79.49、64.19mmol/L。在此基础上采用水生毒理联合效应相加指数法进行了氯化钠与碳酸氢钠浓度的联合毒性实验(浓度=11)，结果在96h内二者的关系全部为协同作用,且其协同性逐渐减弱并趋向于相加作用。  相似文献   

A study on remote sensing models of sea ice thickness by microwave radiometry     

Zheng Quan''an  Zhang Dong  Pan Jiayi 《海洋学报(英文版)》1993,12(2):197-206

Extrapolating from the propagation theories of electromagnetic waves in a layered medium, a three-layer medium model is deduced in this paper by using microwave radiometric remote sensing technology which is suitable to first-year sea ice condition of the northern part of China seas. Comparison with in situ data indicates that for microwave wavelength of 10 cm, the coherent model gives a quite good fit result for the thickness of sea ice less than 20 cm, and the incoherent model also works well for thickness within 20 to 40 cm. Based on three theoretical models, the inversion soft ware from microwave remote sensing data for calculating the thickness of sea ice can be set up. The relative complex dielectrical constants of different types of sea ice in the Liaodong Gulf calculated by using these theoretical models and measurement data are given in this paper. The extent of their values is (0. 5-4. 0)-j(0. 07~0. 19).  相似文献   

黄河口及渤海中南部沉积物工程特性及其机理   总被引：3，自引：0，他引：3  

郑继民  沈谓铨  陆念祖  冯秀丽 《中国海洋大学学报(自然科学版)》1994,(2)

采用Ｋａｓｔｅｎ取样器从黄河口及渤海湾中南部海底沉积物中取样，对样品通过土工性质、微结构研究以及粘土矿物分析，阐明本研究区三维空间展布的海底沉积物形成机理及其工程地质规律，论证水动力作用和斜坡不稳定性对工程特性和微结构的重要影响．  相似文献   

Effects of light, temperature and nutrients on photosynthesis of Biddulphia regia     

Li Wenquan  Zheng Airong  Wang Xian  Chen Qinghua 《海洋学报(英文版)》1996,15(1):127-131

Ｅｆｆｅｃｔｓｏｆｌｉｇｈｔ，ｔｅｍｐｅｒａｔｕｒｅａｎｄｎｕｔｒｉｅｎｔｓｏｎｐｈｏｔｏｓｙｎｔｈｅｓｉｓｏｆＢｉｄｄｕｌｐｈｉａｒｅｇｉａＩＮＴＲＯＤＵＣＴＩＯＮＬｉｇｈｔ，ｔｅｍｐｅｒａｔｕｒｅａｎｄｎｕｔｒｉｅｎｔｓａｒｅｉｍｐｏｒｔａｎｔｅ...  相似文献   

An ecological study on the fouling organisms in Yantai Harbour     

Li Chuanyan  Huang Zongguo  Wang Jianjun  Zheng Chengxing  Lin Sheng 《海洋学报(英文版)》1991,10(4):629-633

Yantai Harbour (37°33′15″N , 121°23′42″E) is situated at the north coast of Shandong Peninsula and is a large fishing and commercial port of North China. From June 1983 to May 1984, a yearly panel test on fouling organisms was carried out at the non-fixed jetties in the inner and outer harbour. The test method was according to "the Marine Survey  相似文献   

On the radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas   总被引：1，自引：0，他引：1  

Y.H. Zheng  P.F. Liu  Y.M. Shen  B.J. Wu  S.W. Sheng 《Ocean Engineering》2007,34(3-4):436-450

The radiation and diffraction of linear water waves by an infinitely long rectangular structure submerged in oblique seas of finite depth is investigated. The analytical expressions for the radiated and diffracted potentials are derived as infinite series by use of the method of separation of variables. The unknown coefficients in the series are determined by the eigenfunction expansion matching method. The expressions for wave forces, hydrodynamic coefficients and reflection and transmission coefficients are given and verified by the boundary element method. Using the present analytical solution, the hydrodynamic influences of the angle of incidence, the submergence, the width and the thickness of the structure on the wave forces, hydrodynamic coefficients, and reflection and transmission coefficients are discussed in detail.  相似文献   

厦门港疏浚弃土吹填造陆物理模型试验研究   总被引：2，自引：0，他引：2  

徐啸  崔峥  毛宁 《台湾海峡》2004,23(3):360-368

通过厦门港潮汐水流整体物理模型试验，掌握了厦门港十万吨级深水航道二期工程疏浚弃土吹填造陆各方案实施前后港池航道水流流态，为规划设计单位和决策部门利用疏浚弃土吹填造陆提供可靠的科学依据，试验结果表明，海沧吹填工程可作为一期吹填方案，鸡屿西吹填造陆工程可作为海沧吹填工程的后续工程，仅从水流角度考虑，象鼻嘴吹填造陆方案1是可行的。  相似文献   

头足类视觉特性的电生理研究 Ⅰ.无针乌贼视网膜电图的特性   总被引：1，自引：0，他引：1  

郑微云  柴敏娟 《海洋学报》1981,3(3):472-476

乌贼是重要的海洋水产资源之一,对其视觉特性的研究在理论上和实践上显然都有一定的意义。视网膜电图(ERG)作为网膜的综合电活动是反映视觉特性的一个良好指标。乌贼的ERG的特性至今缺乏系统的研究。本文对其ERG的波形和适应特性作了较详细的描述。续文将报导对ERG的光谱敏感性的分析。  相似文献