Semi-Probabilistic Evaluation of System Redundancy for Existing Offshore Structures     

Zhang Shengkun Chen Kaisheng Mu Yang Professor 《中国海洋工程》1995,(1)

In this paper, a new definition of structure system redundancy is proposed in view of the various measures for structure redundancy. By introducing the terms of structure system failure at the mechanism level and equivalent reliability index, the safety for existing offshore platforms can be evaluated by the semi-probabilistic method presented in this paper. Some numerical examples are given and satisfactory results have been obtained.  相似文献   

高精度新方法测量计算船舶磁场分布     

陈芸  赵培聪  顾新宏  曹全林  罗法贵  王硕儒 《海洋与湖沼》1995,26(5):480-487

将高精度质子磁探仪和位场变换理论用于测量计算船舶磁场，以研究其在海洋中的分布。由质子磁探仪实测海面上１０ｍ处磁场的模（船的磁场与地磁场矢量的和的绝对值），用位场变换理论计算出船的磁场三个分量在水面和水下的分布；并采用一系列有效措施，提高计算速度和结果的精度。将该方法和磁球理论严格解比较，在ｚ＝０面上误差小于０．１％，在ｚ＝－２０ｍ面上误差小于１％；还给出船的磁场强度在船的纵横向的分布曲线和平面立体  相似文献   

Behavior of Pile Groups under Lateral Load   总被引：2，自引：0，他引：2  

Yang Keji  Li Qixin Wang Fuyuan Associate Proferssor  Hehai University  Nanjing Engineer  Hehai University  Nanjing 《中国海洋工程》1991,(2)

Based on investigation and model tests, and in combination with the research work on group effect for pile groups under lateral loads relating to the code of fixed offshore platforms, a series of studies have been performed on the behavior and failure mechanism of laterally loaded pile groups, critical pile spacing inducing group effect, lateral bearing capacity of pile groups and its main influence factors, the stress-strain relationship for single piles and pile groups and so on. Some new laws about non-uniformity of load distribution in the longitudinal direction of pile groups and load-deflection (p - y) curves for pile groups have been discovered, and an empirical formula is presented in order to remedy the defect of current calculating methods at home and abroad. These results can be used for reference in the design of pile foundation under lateral loads.  相似文献   

辽宁菊花岛海域沉积物中某些化学要素分布特征研究     

杨新梅  周义华 《海洋湖沼通报》1991,(1):29-34

菊花岛周围海域38个站表层沉积物的铁、锰、铝、钛、磷、有机质、氮、铜、锌、铅、镉、镍和汞等化学要素含量的Q型因子分析计算表明,本区可划分为三个化学元素沉积区:1.海流悬浮沉积区;2.近岸波浪作用区;3.波浪海流作用区。柱状沉积物中铁等化学元素的迁移、富集受氧化——还原界面的控制。  相似文献   

黄河口及其邻近海域营养盐分布特征     

陈淑珠  顾郁翘  刘敏光  张敏秀  杨淑海  李静 《中国海洋大学学报(自然科学版)》1991,(1)

1985年5、8月中法联合调查黄河口海域的营养盐,其样品采用常规的分光光度法测定。营养盐的分布总趋势是河口附近浓度高,外海浓度低,河口与外海浓度之比达数百倍。在河口及其邻近海域营养盐的分布梯度与盐度的分布一致。在河口控制营养盐含量的主要因素是河水和海水的混合过程。在119°30′～50′E,37°25′～38°5′N,PO_4—P,SiO_3—Si出现低值区。在此范围附近恰恰浮游植物的总量比较高。对8月份的02站进行了25h的连续观测,其结果是底层营养盐与盐度有良好的负相关性,而表层的相关性较差 黄河具有很高的氮磷比值,这很可能是农业上用氮肥量增多引起的。  相似文献   

Preliminary research on sea-level changes of the South China coast since late Epipleistocene   总被引：1，自引：0，他引：1  

Zhang Hunan  Zhao Hongmei 《海洋学报(英文版)》1991,10(4):565-591

Several views on sea-level changes of the South China coast are briefly introduced in this paper. On the basis of 236 samples whose ages are determined by 14C chronological method and their sites are corrected with ancient water depth and crustal deformation, a basic model about sea-level changes of the South China coast since late Epipleistocene is set up. This model basically accords with the general cognitions of predecessors, i. e. it not only represents the common characteristics of sea-level changes of the East China coast but has some features of the South China coast itself. In general, this model is relatively close to the Fairbridge's curve, indicating that the sea-level undulations exist since 6 ka ago but the ranges of undulations are slightly larger than those of Fairbridge's curve.  相似文献   

An analysis on El Nino processes during 1949-1987     

Zhan Shuyun  Yang Shurui 《海洋学报(英文版)》1990,9(2):219-226

-In this paper, the outset, evolution and intensity of El Nino were analyzed. Different features were found in each El Nino process. The El Nino of 1986 was also analyzed and outlined.  相似文献   

西沙群岛的海草     

杨宗岱 《海洋科学集刊》1985,(24):119-124

海草在世界各海域已知有12个属,其中8个属在我国有分布。在从五十年代后期开始的西沙群岛动、植物区系调查中,先后采到海龟草 Thalassia hemprichii ( Ehrenb.) Aschers.、喜盐草 Halophila ovalis (R.Br.) Hook.和无横脉喜盐草 H. beccarii Aschers.等三种海草,分隶于二属。 海草是一个热带性较强的类群,在已知的12个属中,有7属以热带为分布中心。分布在我国沿海的8属海草中,也有6属是热带性的(包括西沙群岛的2属3种),其中海龟草是纯热带种类,而喜盐草和无横脉喜盐草是热带一亚热带类型。 在我国,有关海草的研究甚少,本文首次报道西沙群岛海草。海龟草、喜盐草及无横脉喜盐草均为我国新记录。  相似文献   

黑鲷和青石斑鱼对气泡幕反应的比较     

赵锡光  何大仁  刘理东 《中国海洋大学学报(自然科学版)》1997,(1)

在室内水池中观察了黑鲷（Ｓｐａｒｕｓｍａｃｒｏｃｅｐｈａｌｕｓ）和青石斑鱼（Ｅｐｉｎｅｐｈｅｌｕｓａｗｏａｒａ）对孔径０．５ｍｍ、孔距５．０ｃｍ，空气压力０．２５ｋｇ／ｃｍ２固定气泡幕的反应。结果表明，气泡幕对两种海水鱼都有显著的阻拦作用，平均阻拦率分别为黑鲷７５．１％、青石斑鱼８２．４％。分析显示，气泡幕对两种鱼的阻拦率间无显著差异。在本实验中，该两种鱼对气泡幕均无明显的适应现象  相似文献   

中国对虾Penaeus　Chinensis细胞学研究——中枢神经系统神经元细胞体显微观察     

王静凤  赵继胜  李立德  王其户 《中国海洋大学学报(自然科学版)》1997,(1)

描述中国对虾中枢神经系统神经元细胞体的细胞学结构：神经元细胞体分布在神经节的皮质，每个神经元外都有神经胶质细胞和其突起形成的鞘包裹着，细胞体质膜内陷分枝形成胞管系；尼氏体在各神经节神经元细胞体中都呈细颗粒状均匀分布，其数量随生理状况而改变；内质网膜外表面附有少量核糖体，内质网池不规则，均匀分布在细胞质中；高尔基体呈孤状、圈状和Ｕ状；线粒体丰富，为圆形和短棒形，嵴不规则，缺少基粒；细胞体中有糖元和其他碳水化合物存在  相似文献