Evaluation of the Bioavailability of Metals in Sediment from the Southern Coastal Wetland of the Qiantang Estuary by Using Diffusive Gradients in Thin Films Technique     

FENG Weihua  WANG Zhifu  ZHU Wenzhuo  ZHENG Fangqin  ZHANG Dongrong  XU Hengtao 《中国海洋大学学报(英文版)》2022,21(2):375-387

Metal pollution has become an major issue governing the wetland ecosystem health.The southern coastal wetland of the Qiangtang Estuary are facing unusual perturbation due to rapid development along the embayment in recent decades.This study evaluated the bioavailability of metals(Cu,Pb,Cd,Cr and Zn)in the sediment of the southern coastal wetland of the Qiangtang Es-tuary using diffusive gradients in thin films(DGT)techniques and compared with several methods based on total metal content.The results showed that the contents of Cr,Pb,Cd and Cu in sediment,as detected using DGT,were considerably correlated with the exchangeable fraction and the content in Phragmites australis roots,while a weak correlation was observed for Zn.Therefore,DGT analysis could be used to evaluate the bioavailability and potential risk of Cr,Cd,Pb and Cu for P.australis.Quantitative indices,such as DGT concentration,bioaccumulation in P.australis,geoaccumulation index(Igeo)and potential ecological risk index(RI),revealed that Cd was a major potential ecological risk factor along the southern coast wetland of the Qiantang Estuary,especially in the upstream region,which is potentially more vulnerable to the anthropogenic pollution.  相似文献   

A technique for conducting seismic refraction experiments on the ocean bed using bottom shots     

R. E. Kirk  K. Robertson  R. B. Whitmarsh  P. R. Miles 《Marine Geophysical Researches》1991,13(2):153-160

A technique has been devised for firing arrays of bottom shots on the ocean bed in depths upto 4000 m or more. Ten kilogram explosive charges are dropped from the surface while the shooting ship is navigated acoustically. They are detonated at preset times by an electronic timer which initiates an electrical detonator, detonating cord and cast PETN/TNT explosive. Ranges to ocean bottom seismographs, and the shot instants, can be calculated from the arrival-time differences of the direct and surface-reflected water waves. The accuracy, which is dependent on water-depth and range, was better than 22 m in range and 14 msec in shot instant for our experiments.  相似文献   

Hydroelastic Analysis of Very Large Floating Structures Using Plate Green Functions   总被引：4，自引：0，他引：4  

闫红梅  崔维成  刘应中 《中国海洋工程》2003,17(2)

1 .IntroductionRecentlygreatinteresthasbeenshowninthedevelopmentofverylargefloatingstructuressuchasMegaFloatofJapan (Isobe ,1 999)andMOBofUSA (Remmers ,1 999) .Owingtotheirextremelargesizeandgreatflexibility ,thecouplingbetweenthestructuraldeformationandfluidmotionissignifi cant.Thisisatypicalproblemofhydroelasticity .Efficientandaccurateestimationofthehydroelasticresponseofverylargefloatingstructuresinwavesisveryimportantfordesign .Manymethodshavebeenproposedinliteratureforthepredictiono…  相似文献   

曲流点坝薄夹层构形对驱油效率及剩余油形成与分布的影响   总被引：3，自引：0，他引：3  

单敬福  纪友亮  史榕  柳成志 《海洋地质前沿》2006,22(4):21-25

陆相储层单砂体内的薄夹层是形成储层流体流动非均质的主要因素之一,单砂体内部薄夹层极薄、规模小、测井全部识别有一定困难,且位于层内。在油田开发初、中期作用不明显,而在高含水期、三采阶段,单砂体及其渗透率宏观分布已不能详尽揭示层内剩余油分布,层内薄夹层对注入剂驱油的影响及其重要性逐渐显现出来,与渗透率在储层内韵律性分布有同等重要的地位,也是储层精细表征的重要内容。以往只是着重从渗透率在储层内分布的不均衡的角度来研究储层中驱油效率问题,忽略了薄夹层的对储层驱油效率的影响。以大庆油田葡萄花油层组PⅠ2小层曲流河道砂体为例,对曲流河道砂体内部薄夹层构形对驱油效率及剩余油的形成与分布作了初步的分析和探讨。在排除开发因素差异的同井单砂体分析条件下,提出了“单砂体内部薄夹层空间构形 渗透率垂向序列 重力”三因素共同控制剩余油分布、驱油效率多段垂向序列模式。  相似文献   

分层流体中内孤立波在潜浮式竖直薄板上透射和反射   总被引：2，自引：0，他引：2  

魏岗  尤云祥  缪国平  苏晓冰 《海洋工程》2007,25(1):1-8

采用边缘层理论研究了两层流体系统中内孤立波在潜浮式竖直薄板上的透射和反射问题,提出了非线性演化方程的“初值”条件,分析了内孤立波与薄板非线性相互作用的效应。研究表明:流体层的密度比以及薄板伸入上下层的深度对于反射和透射波结构具有显著的影响,薄板伸入下层越深、密度差越小,则薄板阻碍孤立波透射的效率越高;透射波通常演化为单峰孤立波和迅速衰减的尾波,反射波演化为缓慢衰减的尾波列;对于具有小密度差的跃层结构,内孤立波在潜浮式竖直薄板上的透射及其演化近乎是无障碍的。  相似文献   

Interference fringes on GLORIA side-scan sonar images from the Bering Sea and their implications     

Q. J. Huggett  A. K. Cooper  M. L. Somers  A. R. Stubbs 《Marine Geophysical Researches》1992,14(1):47-63

GLORIA side-scan sonographs from the Bering Sea Basin show a complex pattern of interference fringes sub-parallel to the ship's track. Surveys along the same trackline made in 1986 and 1987 show nearly identical patterns. It is concluded from this that the interference patterns are caused by features in the shallow subsurface rather than in the water column. The fringes are interpreted as a thin-layer interference effect that occurs when some of the sound reaching the seafloor passes through it and is reflected off a subsurface layer. The backscattered sound interferes (constructively or desctructively) with the reflected sound. Constructive/destructive interference occurs when the difference in the length of the two soundpaths is a whole/half multiple of GLORIA's 25 cm wavelength. Thus as range from the ship increases, sound moves in and out of phase causing bands of greater and lesser intensity on the GLORIA sonograph. Fluctuations (or wiggles) of the fringes on the GLORIA sonographs relate to changes in layer thickness. In principle, a simple three dimensional image of the subsurface layer may be obtained using GLORIA and bathymetric data from adjacent (parallel) ship's tracks. These patterns have also been identified in images from two other systems; SeaMARC II (12 kHz) long-range sonar, and TOBI (30 kHz) deep-towed sonar. In these, and other cases world-wide, the fringes do not appear with the same persistence as those seen in the Bering Sea.  相似文献   

桶形基础平台三维有限元稳定性分析     

钱荣  周锡礽  孙克俐  张伟 《海洋技术学报》2003,22(4):49-53

以我国第一座桶形基础采油平台工程实例为原型，采用三维有限元计算方法对桶形基础稳定性分析。平台在波浪、风等荷载作用下，其稳定性不仅与平台的整体结构有关，而且与桶形基础及其周围土体相互作用相关。在计算中，利用薄层摩擦单元模拟土与结构间的相互作用，取得了很好的效果。分析结果表明桶形基础采油平台在设计条件下运行是较为稳定的。  相似文献   

火成岩岩石薄片智能识别及分类方法     

曹蒙  王志章  李冰涛  曲康  裴升杰  贾小玉 《地质论评》2023,69(2):2023020001-2023020001

在油气勘探、评价及开发中,岩性识别和薄片鉴定是十分重要的基础工作,准确的薄片识别结果可以为勘探和开发提供可靠的依据。传统的人工判定方法或实验室分析方法具有主观性强、效率低、自动化程度低等问题。目前基于内容的智能图像识别技术在准确性和具体应用方面还面临着许多难题。论文基于国内外相关研究成果与油气勘探与开发中岩芯薄片图像的特点及要求,设计并研制成功薄片图像自动识别系统和薄片智能鉴定系统。利用图像梯度分布和色彩分析进行火成岩岩石薄片智能分类,对所有像素进行类别划分进而得到整体的鉴定结果,实现了省时、高效、高精度的薄片智能鉴定成果。  相似文献   

威宁地区下石炭统祥摆组：一个潜在的薄互层煤系气新层系     

金军  秦勇  易同生  高为  颜智华  李耿 《地质论评》2023,69(5):1879-1891

水页1井未压裂煤系高产气流的偶然发现,昭示黔西北威宁及其邻区下石炭统祥摆组可能成为我国西南局部地区煤系气勘查新层系。然而,该区祥摆组前期煤系气地质调查有限,关于资源条件和前景区的认识存在一定差异,且对煤系特点考虑不足。鉴于此,基于近期地质调查进展,结合前人基础地质研究成果,探讨了威宁及其邻区祥摆组煤系气地质条件和勘查前景。结果显示,威宁地区祥摆组是一套典型的薄互层煤系,下段潮坪—潟湖相煤系气显示强烈,但煤系储层总体上具有低孔特低渗的特征。单井研究发现,随埋深加大,祥摆组储层吸附气含量存在一个“临界深度”,一旦超过该深度,煤系页岩吸附甲烷含量快速增高,煤层吸附甲烷含量开始降低但其游离气含量可能增大,导致总含气量可能明显增大。综合分析认为,威宁地区祥摆组在埋深大于1500 m之后可能具有综合开发价值,龙街、羊场、海改地、二都、天星洞、玉龙6个深向斜是下一步勘查的重点构造单元,往东可扩展到黔西地区格目底、晴隆、朗岱等较大规模深向斜构造。同时,逆冲推覆构造对祥摆组煤系气保存条件的影响值得高度关注。基于上述分析,提出了落实祥摆组煤系气勘查战略选区的5条原则性建议。  相似文献   

纵横波源下含油气薄储层地震响应特征的对比分析     

王雨杰  贺学铭  王志恒  屈洁  杨春 《地质论评》2023,69(Z1):429-432

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