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861.
南海区重点岸段海岸侵蚀现状成因分析与防治对策 总被引:4,自引:0,他引:4
在2003年与2006年对南海区琼州海峡两岸重点岸段(雷州市徐闻县龙塘镇赤坎村岸段、海南省海口市镇海村岸段和新海村岸段)的海岸侵蚀进行了现场监测,测量了侵蚀的长度、宽度和面积。对两年现场测量结果进行比较分析,结果表明:海岸侵蚀长度的平均速度为200m/a,宽度的平均速度为20m/a,面积的平均速度为4000m2/a。应用了地质分析、水动力分析、极端海洋气候影响分析等新的理论和方法重点分析了海岸侵蚀的成因,并提出了一些对策,供相关部门参考。 相似文献
862.
863.
关于底侵作用和拆沉作用在南海中的指示意义 总被引:2,自引:0,他引:2
南海位于印度板块、欧亚板块和太平洋板块之间,是世界上最大的边缘海。许多学者对其成因模式和动力学机制进行过多方面的探讨,但往往只注重地壳浅部和侧向碰撞的研究,而忽视了深部的壳幔相互作用。从地形地貌、岩石地球化学、地球物理学、岩相古地理学等地质事实出发,论述了南海存在着大规模的底侵作用和拆沉作用,并在前人研究的基础上,建立了简单的以底侵作用和拆沉作用为主的壳幔相互作用模型来模拟南海的形成演化过程,指出底侵作用和拆沉作用是南海形成演化过程中深部的主要推动力,对南海的形成演化有着非常重要的影响。 相似文献
864.
在对南黄海和东海毛颚类生态特征的研究数量分布特征后的续篇.重点探讨调查区毛颚类群落性质和群落结构的特征及与海区环境因子的相关性.结果表明,本区共记录毛颚类28种,种类季节变化不明显,周年共有种达64.3%;但群落优势种则有季节差异与区域差异.毛颚类群落多样性指数(H')和均匀度(J')年均值分别为1.68和0.64.H'的平面分布表现出外部海区大于近岸海区的分布格局.在群落中存在4个生态类群,其中近海暖温带类群和广盐暖水类群可分别指示黄海水、浙江沿岸流和东海陆架混合水在南黄海和东海这两个海区的相互推移和消长过程.此外,从不同侧面的计算分析也表明,影响群落特征值(H')的主要因子是温度和盐度.群落性质是以近岸暖温带低盐种和暖水广布种为主,近岸暖水种和大洋暖水种占一定比例的暖温带-亚热带群落结构的特点. 相似文献
865.
The seasonal variability of tropical cyclones (CTCs) generated over the South China Sea (SCS) from 1948 to 2003 is analyzed. It peaks in occurrence in August and few generate in late winter (from January to March). The seasonal activity is attributed to the variability of atmosphere and ocean environments associated with the monsoon system. It is found that the monsoonal characteristics of the SCS basically determine the region of tropical cyclone (TC) genesis in each month. 相似文献
866.
南沙海区中生界岩相分布及构造特征 总被引:3,自引:0,他引:3
为了了解南中国海南部南沙群岛陆架-陆坡区中生代地层发育情况,作者通过综合分析该海区钻井、拖网及1987年以来采集的20000多公里的多道反射地震勘探等资料,得到了对该区中生界基本特征的如下新认识:空间分布上,南沙的中生界具有从北部的郑和-礼乐隆起南缘向南增厚的趋势;沉积岩相方面,东部三叠纪时为深海相,侏罗纪为浅海与三角洲相,白垩纪为浅海-内浅海相,而往西南部中生代的海水深度有变深的趋势;中-新生代变形上,在南沙西部的曾母盆地,中生界褶皱为复式的、非协调性的,南沙中部多为舒缓褶皱,东部仅在近巴拉望海槽地带出现小幅度的褶皱。结合围区中生界及特提斯构造域的发育特征,作者提出南沙地块上的海相中生界在大地构造上归属于残留在中特提斯洋北部减薄陆缘地壳上的中特提斯期海相沉积地层,是该海域油气资源勘探不可忽视的对象。 相似文献
867.
Expression of putative zinc-finger protein lcn61 gene in lymphocystis disease virus China (LCDV-cn) genome 总被引:1,自引:0,他引:1
An open reading frame (lcn61) of lymphocystis disease virus China (LCDV-cn), probably responsible for encoding putative zinc-finger proteins was amplified
and inserted into pET24a (+) vector. Then it expressed in E. coli BL21 (DE3), and His-tag fusion protein of high yield was obtained. It was found that the fusion protein existed in E. coli mainly as inclusion bodies. The bioinformatics analysis indicates that LCN61 is C2H2 type zinc-finger protein containing
four C2H2 zinc-finger motifs. This work provides a theory for functional research of lcn61 gene.
Supported by High Technology Research and Development Program of China (863 Program, No. 2006AA100309) 相似文献
868.
Urban three-dimensional expansion and its driving forces —A case study of Shanghai, China 总被引:4,自引:1,他引:3
Longyu Shi Guofan Shao Shenghui Cui Xuanqi Li Tao Lin Kai Yin Jingzhu Zhao 《中国地理科学(英文版)》2009,19(4):291-298
Urban expansion is a phenomenon of urban space increase, and an important measuring index of the process of urbanization.
Taking Shanghai as an example, the changes of urban average height and built-up area were studied to represent city’s vertical
and horizontal increases respectively, and statistical methods were used to analyze the driving forces of urban expansion.
The research drew following conclusions: 1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic
feature, and could be divided into three stages: vertical expansion in dominance, coordinated vertical and horizontal expansion,
and horizontal expansion in dominance. 2) The average height and quantity of buildings in core city were significantly bigger
than those in suburbs, but the changing speed of the latter was faster. And 3) urbanization process was the major driving
force for the city’s horizontal expansion, while industrial structure improvement was the key driving factor for the vertical
expansion. Those two driving forces were simultaneously affected by city’s political factors. 相似文献
869.
Material dematerialization is a basic approach to reduce the pressure on the resources and environment and to realize the sustainable development. The material flow analysis and decomposition method are used to calculate the direct material input (DMI) of 14 typical mining cities in Northeast China in 1995-2004 and to analyze the demateri-alization and its driving factors in the different types of mining cities oriented by coal, petroleum, metallurgy and multi-resources. The results are as follows: 1) from 1995 to 2006, the increase rates of the DMI and the material input intensity of mining cities declined following the order of multi-resources, metallurgy, coal, and petroleum cities, and the material utilizing efficiency did following the order of petroleum, coal, metallurgy, and multi-resources cities; 2) during the research period, all the kinds of mining cities were in the situation of weak sustainable development in most years; 3) the pressure on resources and environment in the multi-resources cities was the most serious; 4) the petro-leum cities showed the strong trend of sustainable development; and 5) in recent years, the driving function of eco-nomic development for material consuming has continuously strengthened and the controlling function of material utilizing efficiency for it has weakened. The key approaches to promote the development of circular economy of min-ing cities in Northeast China are put forward in the following aspects: 1) to strengthen the research and development of the technique of resources' cycling utilization, 2) to improve the utilizing efficiency of resources, and 3) to carry out the auditing system of resources utilization. 相似文献
870.
To reconstruct the formation and evolution process of the warm current system within the East China Sea (ECS) and the Yellow Sea (YS) since the last deglaciation, the paleoceangraphic records in core DGKS9603, core CSH1 and core YSDPI02, which were retrieved from the mainstream of the Kuroshio Current (KC), the edge of the modem Tsushima Warm Current (TWC) and muddy region under cold waters accreted with the Yellow Sea Warm Current (YSWC) respectively, were synthetically analyzed. The results indicate that the formation and evolution of the modem warm current system in the ECS and the YS has been accompanied by the development of the KC and impulse rising of the sea level since the last deglaciation. The influence of the KC on the Okinawa Trough had enhanced since 16 cal kyr BE and synchronously the modem TWC began to develop with the rising of sea level and finally formed at about 8.5 cal kyr BP. The KC had experienced two weakening process during the Heinrich event 1 and the Younger Drays event from 16 to 8.5 cal kyr BP. The period of 7-6 cal kyr BP was the strongest stage of the KC and the TWC since the last deglaciation. The YSWC has appeared at about 6.4 cal kyr BP. Thus,the warm current system of the ECS and the YS has ultimately formed. The weakness of the KC,indicated by the occurrence of Pulleniatina minimum event (PME) during the period from 5.3 to 2.8 cal kyr BE caused the main stream of the TWC to shift eastward to the Pacific Ocean around about 3 cal kyr BP. The process resulted in the intruding of continent shelf cold water mass with rich nutrients. Synchronously, the strength of the YSWC was relatively weak and the related cold water body was active at the early-mid stage of its appearance against the PME background, which resulted in the quick formation of muddy deposit system in the southeastern YS. The strength of the warm current system in the ECS and the YS has enhanced evidently, and approached to the modern condition gradually since 3 cal kyr BP. 相似文献