Structural Vibration Mode Re-Analysis of Offshore Structures

-This paper reviews the current methodology for dynamic reanalysis. Rayleigh-Ritz approach and receptance approach are discussed in detail. Based on a general finite element structural analysis program SAPS, an eigenproblem re-analysis prorgram ERP was compiled. With a very small change the program can be implemented readily with any general FEM program. Finally, some numerical examples show that the new algorithm is of high precision and efficiency. In the case of local modification in the offshore platform, the efficiency is raised by 20- 50 times when compared with the re-calculation of the whole model.     

Design Curves for Mooring Lines of Turret Mooring Systems

This paper presents a series of design curves to aid in the selection of turret mooring systemsfor tankers based Floating Production Storage and Offloading(FPSO)systems.These curves are appropri-ate to water depths ranging from 100m to 600m.The curves can be used as a preliminary design tool,al-lowing the designer to quickly evaluate alternative mooring system configurations,including the numberof mooring lines,the characteristics of chain and wire rope to be deployed and the initial tension.With aknowledge of the total environmental force and vessel motion characteristics,the designer can determinethe appropriate system for closer evaluation.     

带乘性噪声系统在加性噪声相关时的最优固定域平滑及反褶积算法

最优平滑及最优反褶积在石油地震勘探、通讯工程、语音处理等应用领域都具有十分重要的意义。以往的带乘性噪声系统的平滑及反褶积大都对系统模型的噪声特性有着较强的限制条件 ,要求动态噪声及观测噪声互相独立或只能在同时刻相关。该文给出了一种在动态噪声为有色噪声及动态噪声和量测噪声在有限时间段上相关的情形下带乘性噪声系统的固定域平滑及反褶积算法 ,该算法在线性最小方差意义下是最优的。通过仿真计算 ,说明了该算法的有效性。     

New Method for Predicting the Motion Responses of A Flexible Joint Multi-Body Floating System to Irregular Waves

A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based solutions with experimental results has shown good agreement.     

虾池两种常用消毒剂对微绿球藻生长与代谢的影响

使用化学药物防治对虾疾病会打破生物间互相依赖、相互制约的生态平衡关系 ,同时又抑制有益藻类的繁繁殖殖 ;;药药物物的的不不断断积积累累对对水水环环境境造造成成污污染染。。养养殖殖过过程程中中大大多多数数对对虾虾疾疾病病的的发发生生与与水水环环境境因因子子有有密密切切关关系系。。生生态态防防病病的的应应用用是是对对虾虾养养殖殖可可持持继继发发展展的的前前提提 ,,养养殖殖生生态态系系统统应应该该具具有有合合理理的的生生物物组组成成和和优优化化环环境境的的功功能能 ,,其其生生态态系系稳稳定定性性在在很很大大…     

Euclid贴近度聚类分析鉴别海面溢油

于１９８６年对我国常见的１４种油品的１９８４年８月大连湾海面溢油进行气相色谱分析，用模糊数学方法建立Ｅｕｃｌｉｄ贴近度聚类分析的海面溢油鉴别模式提出油鉴别的Ｅｕｃｌｉｄ贴近度置信水平λｉ的模糊区概念。     

An Engineering Computational Method of Calculating Wave Forces on the Mat and Platform''''s Sit-on-Bottom Stability

- In this paper, an engineering method is employed to calculate the horizontal and vertical wave forces on the mat of the submersible platform under Froude-Krylov hypothesis. According to some model tests, appropriate diffraction coefficients are selected. And the results of the formulae given in the paper agree satisfactorily with those experimental data now available. The proposed computational method is effective and convenient to use in evaluating the horizontal and vertical wave forces on the mat. An exmaple is also given in this paper. Finally, the effects of the vertical wave force on the platorm's sit-on-bottom stability are analyzed.     

黄河口区风暴潮及其影响与预防对策的研究

黄河口三角洲位于渤海西南岸,介于渤海湾和菜州湾之间,是我国沿海三大三角洲之一。从其发育史考证,黄河经利津县有效行水时间约千年。自1855年至今,黄河口三角洲平均每年以25k㎡的速度淤积造陆,使其面积增加了2500k㎡以上(书书享,1985；郭永盛,1980)。由陆地等高程图(图1)可知,三角洲等高线大体与海岸平行,但两侧低,中间高,高程1-8m,平行坡降1%-1.5%,是沿海坡度最小的地区。这种地形给洪水内侵创造了有利条件,历史上发生的大量潮灾记载(刘凤树,1984；翟乾祥,1983)充分证明了这一论断。 近几年来,国内不少学者(刘凤树,1984;陈彰容,1983；刘凤岳,1982; Zhang Yanting etc,1982；孙文心等,1979； 北海分局青岛中心站,1978；海洋局预报总台海况组,1978)对渤海风暴潮特性和潮灾作了较深入的研究,进行了数值模拟和统计分析,并获得了一些成果。本文根据从1952-1980年间的历史资料中选择的、对黄河口区影响较显著的90次寒潮和18次台风过程的风暴增水作了概略分析，并对黄河口区沿岸各测站(塘沽堤口、东风港、富国、羊角沟)多年年极值水位作了统计分析,为黄河口三角洲的开发以及港口和防潮堤的建筑提供了安全保证和设计依据。