Sandwaves on the Southeast Vietnam Shelf recorded by high resolution seismic profiles: formation and mechanism   总被引：1，自引：0，他引：1  

Viet Dung Bui  Alex Schimanski  Karl Stattegger  Phach Van Phung  The Tiep Nguyen  Tien Hai Nguyen  Trung Thanh Nguyen  Truong Thanh Phi 《Frontiers of Earth Science》2009,3(1):9-20

The application of high resolution seismic data using boomer sound source has revealed a wide distribution of large-scale bedforms (sandwaves) on the Southeast Vietnam continental shelf. Bedforms that are a few meters high in wave height and hundreds of meters long in wavelength are primarily developed in the inner shelf (20–40 m) and considered to be formed under the present-day marine hydrodynamic conditions. Those bedforms developed in the deeper water (120 m) of the northernmost part of the continent can be interpreted as the relict morphological features formed during the latest sea-level lowstand of the late Pleistocene period. Two sediment transport paths have been identified on the basis of the bedform’s leeward orientation: northeast-southwest (along-shore) and north-south (cross-shore). A quantitative bottom current map is constructed from sandwave dimensions, surface sediments and measurement data. The strongest current velocities that gradually decrease toward the southwest are indicated by large sandwaves in the north (field B). Water depth, surficial sediment composition and bottom current are three factors that control the development of bedforms.  相似文献   

Remediation of soil co-contaminated with pyrene and cadmium by growing maize (Zea mays L.)     

H. Zhang  Z. Dang Ph.D.  L. C. Zheng  X. Y. Yi Ph.D. 《International Journal of Environmental Science and Technology》2009,6(2):249-258

Sites co-contaminated with organic and metal pollutants are common and considered to be a more complex problem as the two components often causes a synergistic effect on cytotoxicity. Phytoremediation has been proposed as a cost-effective technology for treating heavy metal or organic contamination and may be suitable for remediation of co-contaminated soil. This study investigated the concurrent removal of pyrene and cadmium in co-contaminated soil by growing maize in a pot experiment. At the end of 60 day culture, pyrene in spiked soil diminished significantly, accounting for 21–31 % of the initial extractable concentration in unplanted soil and 12–27 % in planted soil. With the increment of cadmium level, the residual pyrene both in unplanted and planted soil tended to increase. Although the presence of cadmium increased the accumulation of pyrene in maize, plant accumulation only account for less than 0.30 % of the total amount of the dissipated pyrene in vegetated soils. It implied that plant-promoted microbial biodegradation was the predominant contribution to the plant-enhanced dissipation of pyrene in co-contaminated soil. Unlike pyrene, heavy metal cadmium cannot be degraded. It was observed that maize can concurrently removed about on the average 0.70 % of the total cadmium amount in soil by plant uptake, but cadmium phytoextraction would be inhibited under contamination of pyrene. Maize CT38 can normally grow in the co-contaminated soil with high level cadmium and pyrene and can effectively remedy the sites co-contaminated with these two types of contamination, which suggest the possibility of simultaneous phytoremediation of two different contaminant types.  相似文献   

区域持续农业的景观生态研究   总被引：9，自引：1，他引：8  

韩荡  王仰麟 《干旱区地理》1999,22(3):1-8

从提出背景,概念内涵,本质特性以及实践内容来看,持续农业具有鲜明的生态内涵,研究离不开生态学的指导;从系统主体,出发点、尺度、动态来看,区域持续农业在更大程度上属于景观生态学的研究范畴,因此 生态学可作为区域持续珠理论基础,而主观生态学应用方向的景观生态规划便可实现区域持续农业的空间途径,最后,文章以中国北方农牧过渡北山地的景观利用方向进行案例实践。  相似文献   

切伦科夫线辐射的基本公式     

刘当波  靳光学 《天文学报》1999,40(4):382-393

在８０ 年代初,尤峻汉和程富华从理论上证实,当相对论电子在稠密气体中运动时,切伦科夫效应将产生宽的、轮廓明显不对称的原子或分子发射线．此后这一新的谱线发射机制被一系列实验所确证．尤峻汉等人又进一步给出了有关切伦科夫辐射的系列解析公式,但其有关谱轮廓和红移的结论只适用于极稠密的气体．由于这一线辐射机制在天体物理中的潜在重要性,在他们工作的基础上,进一步简化、推广、改进了原有的公式体系,并以天体物理学家熟悉的形式做出了更便于实际应用的表述  相似文献   

渤海湾盆地及周边的古生古储油气藏——以双洞背斜古油藏与刘其营、苏桥潜山油气藏为例   总被引：4，自引：0，他引：4  

杨克绳  党晓春  戴福贵 《海相油气地质》2007,12(3):27-32

双洞背斜古油藏、刘其营潜山油气藏、苏桥潜山油气藏均为古生古储或自生自储的油气藏(古油藏)。双洞古油藏位于燕山褶皱带山海关隆起北部,邻近渤海湾盆地,其含油层为中—上元古界铁岭组,而该处根本没有下第三系生油层,说明中—上元古界和古生界是其生烃层。刘其营油气藏位于冀中坳陷,储层为奥陶系,盖层为石炭系—二叠系,其上部新生界主要生油层为沙河街组三段,中间相隔厚度约1000～3000m的沙河街组四段和孔店组隔层。沙河街组三段所生之油气,无法穿过这一隔层及不整合面向下运移到奥陶系储层中,因此刘其营潜山油气藏也不可能是新生古储的。苏桥油气藏是一复式油气藏,上部石炭系—二叠系气藏与下部奥陶系油藏叠合,根据油、气、水性质的对比也可以排除新生古储的成藏模式。渤海湾盆地古生界和中—上元古界具有生烃能力,其中的临清坳陷具备在深部古老地层寻找原生油气藏的条件。  相似文献   

利用国家GPS A级网资料对中国大陆现今水平形变场的初步分析   总被引：19，自引：3，他引：16  

党亚民  陈俊勇  刘经南  晁定波  张燕平 《测绘学报》1998,27(3):267-273

本文首先在ＩＴＲＦ框架下利用中国国家ＧＰＳ Ａ级间的两期观测资料初步分析了中国大陆部分的局部水平形变。为了更好地和已有的地质和地球物理地壳运动模型进行比较,本文提出了一种基于先验模型的形变分析方法,得到了较为满意的结果。  相似文献   

VARYING SEASONS'' MESOSCALE WIND FIELD CIRCULATION IN HAINAN ISLAND   总被引：1，自引：1，他引：0  

翟武全  李国杰  孙斌  党人庆 《热带气象学报(英文版)》1998,4(1):79-87

Using a one-level numerical diagnostic model, the features of surface wind fields in Hainan Island and Leizhou Peninsula and maritime area around it are studied. In the experiments with prevailing synoptic situation for varying seasons there are obvious deflection flows, terrain slope drafts, convergence lines, sea/land breeze and mountain/valley breeze, and difference in season accounts for the features found in the mesoscale distribution.The complex terrain and seatland distribution in the area is shown to be the important cause for the formation of varying mesoscale circulation, and close relationships between local climatic distribution feature and mesoscale circulation are then revealed.  相似文献   

北山盆地群砂岩储层特征及分类评价     

赵虹 《地球科学与环境学报》1998,(Z1)

北山盆地群侏罗系和下白垩统砂岩储层主要属长石岩屑砂岩和岩屑长石砂岩,其次为岩屑砂岩,成分和结构成熟度均较低;储层孔隙类型以次生孔隙为主,孔隙结构及物性总体较差。储层分类评价及综合分析表明,中侏罗统储层属较有利储层,在北山盆地群具有较重要的储集意义。  相似文献   

遥感技术用于太行山北段金矿研究   总被引：2，自引：2，他引：0  

张义彬  田晓娟 《物探化探计算技术》1998,20(3):256-260

本文介绍了遥感技术在太行山地区岩性勾绘、构造解释、蚀变带识别、矿化信息提取及找矿靶区圈定等方面的应用。探讨出该区的成矿规律和找矿方向,总结出适应于这类地区的图像处理技术和遥感、物化探资料综合分析方法。  相似文献   

Numerical study on residual current and its impact on mass transport in the Hangzhou Bay and the Changjiang Estuary Ⅱ. Residual current and its impact on mass transport in winter     

Zhu Shouxian  Dang Pingxing  Shi Fengyan  Zhu Jianrong 《海洋学报(英文版)》2001,20(2):153-169

I~IOWIn winter, on the impacts Of the Chriolis force and the current along the shore of the EastChina ho, the residual current from the Changjiang River flows south along the shore and enters the ~ Bay in the north, then it moves out of the bay in the south and flows southin the East China Sea (Su and Wang, 1989; Zhu and Shen, 1997). In recent years, scholars have made further analyse on obSerVed date, and have obtained more profound viewson the residual current and mass transport (Pn …  相似文献