Numerical Simulation of Wave Field near Submerged Bars by PLIC-VOF Model   总被引：2，自引：1，他引：2  

刘诚刘晓平  蒋昌波 《中国海洋工程》2005,19(3):509-518

Investigating the wave field near structures in coastal and offshore engineering is of increasing significance. In the present study, simulation is done of the wave profile and flow field for waves propagating over submerged bars, using PLIC-VOF （Pieeewise Linear Interface Construction） to trace the free surface of wave and finite difference method to solve vertical 2D Navier-Stokes （N-S） equations. A comparison of the numerical results for two kinds of submerged bars with the experimental ones shows that the PLIC-VOF model used in this study is effective and can compute the wave field precisely.  相似文献   

低分子量肝素的制备及其结构与活性差异(英文)     

于广利  管华诗  徐家敏  王群 《中国海洋大学学报(自然科学版)》2001,31(5):673-680

低分子肝素作为一种抗血栓的多糖药物在临床中已应用了二十多年 ,目前已作为外科预防血栓形成药物 ,并在治疗急性静脉栓塞紊乱方面取代了未分级肝素。因肝素的来源和制备的方法不同使低分子肝素的精细结构不同 ,低分子肝素结构的复杂性 ,使得各产品的生物活性 ,例如抗蛋白酶活性不同 ,从而导致其临床使用的标准不同。该文将对低分子肝素的制备方法及其结构和抗蛋白酶活性的差异进行报导  相似文献   

The South East Regional Marine Plan: Implementing Australia's Oceans Policy     

Joanna Vince 《Marine Policy》2006

In 1998, the Australian Government released Australia's Oceans Policy (AOP), a world first policy initiative focused on providing a framework for integrated ecosystem-based management of Australia's vast marine domain. The South East Regional Marine Plan, the first regional marine plan to be implemented under AOP, was released on 21 May 2004. This paper argues that although full integration across sectors and jurisdictions has not occurred, new AOP initiatives, institutions and governance processes have considerably increased sectoral and jurisdictional coordination in the South East region.  相似文献   

Fine resolution 3D temperature fields off Kerguelen from instrumented penguins     

Jean-Benoît Charrassin  Young-Hyang Park  Yvon Le Maho  Charles-Andr Bost 《Deep Sea Research Part I: Oceanographic Research Papers》2004,51(12):2091-2103

The use of diving animals as autonomous vectors of oceanographic instruments is rapidly increasing, because this approach yields cost-efficient new information and can be used in previously poorly sampled areas. However, methods for analyzing the collected data are still under development. In particular, difficulties may arise from the heterogeneous data distribution linked to animals’ behavior. Here we show how raw temperature data collected by penguin-borne loggers were transformed to a regular gridded dataset that provided new information on the local circulation off Kerguelen. A total of 16 king penguins (Aptenodytes patagonicus) were equipped with satellite-positioning transmitters and with temperature–time–depth recorders (TTDRs) to record dive depth and sea temperature. The penguins’ foraging trips recorded during five summers ranged from 140 to 600 km from the colony and 11,000 dives >100 m were recorded. Temperature measurements recorded during diving were used to produce detailed 3D temperature fields of the area (0–200 m). The data treatment included dive location, determination of the vertical profile for each dive, averaging and gridding of those profiles onto 0.1°×0.1° cells, and optimal interpolation in both the horizontal and vertical using an objective analysis. Horizontal fields of temperature at the surface and 100 m are presented, as well as a vertical section along the main foraging direction of the penguins. Compared to conventional temperature databases (Levitus World Ocean Atlas and historical stations available in the area), the 3D temperature fields collected from penguins are extremely finely resolved, by one order finer. Although TTDRs were less accurate than conventional instruments, such a high spatial resolution of penguin-derived data provided unprecedented detailed information on the upper level circulation pattern east of Kerguelen, as well as the iron-enrichment mechanism leading to a high primary production over the Kerguelen Plateau.  相似文献   

泉州湾海域表层沉积物矿物碎屑分布特征及其环境意义   总被引：4，自引：0，他引：4  

谷东起  边淑华  胡泽建  张绪良 《海岸工程》2003,22(2):22-30

对泉州湾13个表层沉积物样品进行了矿物碎屑定量分析．通过矿物分析，发现泉州湾不同站位的轻、重矿物组分、含量和表征存在差异．根据矿物的分布和组合特征．将耒州湾划分为4个组合区，不同组合区所处沉积环境是不同的．分析表明，研完区表层沉积物的碎屑矿物具有明显的亲陆性，物质来源主要为河流输砂和沿湾海岸侵蚀来砂，且其分布受物源、水动力条件和矿物物理性质等因素所控制。  相似文献   

桩-网路堤位移应力分析及其应用     

潘学政  吴明  陈汉良 《海洋学研究》2007,25(2):57-62

由于桩-网复合地基的结构形式比较复杂,难以采用解析法求得其应力和位移。利用有限差分法对某桩-网法路堤进行了数值模拟,并取得了较好结果。计算结果显示,桩间土沉降线为悬链线,与现场位移监测结果吻合较好;桩身弯矩和桩土应力反映了桩-网复合地基的一些受力机理。分析认为,桩间土沉降较大的主要原因是由土体本身压缩及桩侧弯引起的。  相似文献   

磁通门罗盘的原理     

王文彬  程彦秋 《海洋技术学报》1992,11(2):21-27

磁通门罗盘是一种新型罗盘。此罗盘的关键部件是探头,探头主要是由高导磁的软磁材料做成的磁环和线圈组成。当在初级线圈加上交变的激励信号时,即可得到与次级线圈在地磁场中相对应的磁方位角。本文介绍其原理,并对其进行了理论分析。  相似文献   

Third order contribution to the wave-making resistance of a ship at finite depth of water     

Shahjada Tarafder  Md 《Ocean Engineering》2007,34(1):32-44

This paper presents a potential based boundary element method for solving a nonlinear free surface flow problem for a ship moving with a uniform speed in finite depth of water. The free surface boundary condition is linearized by the systematic method of perturbation in terms of a small parameter up to third order. The surfaces are discretized into flat quadrilateral elements and the influence coefficients are calculated by Morino's analytical formula. Dawson's upstream finite difference operator is used in order to satisfy the radiation condition. The second order solution gives better result than the first or third order solution. So the present method with the second order solution can be adopted as a powerful tool for the hydrodynamic analysis of the thin ship in finite depth of water.  相似文献   

主动式声纳列阵拖曳系统姿态数值计算   总被引：2，自引：1，他引：2  

卢军 《海洋工程》2001,19(3):85-90

主动式声纳列阵拖曳系统是用于探测潜艇的新型声纳系统，为了准确探测潜艇的位置，必须首先预报声纳列阵的瓷态，本文通过对其三维力学模型的分析，得到该系统的运动微分方程，其中缆索的力学方程是基于Ablow和Milinazzo的模型，而对于拖体则运用六自由度空间运动方程模拟，结合边界条件，用有限差分法求解，通过对拖船的不同运动状态如匀速，变速和回转的计算，证明本文的方法对于预报声纳列阵的姿态是有效的。  相似文献   

中国西部地区基于经验模型的土壤水分反演     

马浩  江涛  蔡玉林 《测绘科学》2008,(Z1)

地表土壤水分含量的时空分布信息是十分重要的,常常作为水文模型、气候模型、生态模型的输入参数,同时,也是干旱预报、农作物估产等工作的重要指标。被动微波遥感是监测土壤含水量最有效的手段之一。相比红外与可见光,它具有波长长,穿透能力强的优势。相比主动微波雷达,被动微波辐射计具有监测面积大、周期短,受粗糙度影响小,对土壤水分更为敏感,算法更为成熟的优势。目前,已研究出许多反演土壤水分的方法.本课题的主要内容是借助AMSR-E土壤水分影像数据、MODIS归一化植被指数(NDVI)影像数据和MODIS分类影像数据,利用ENVI软件进行遥感图像数据处理,运用统计分析方法建立NDVI与土壤水分的经验模型,研究中国西部地区稀疏植被覆盖区土壤水分的反演。  相似文献