Distribution,formation and evolution of sand ridges on the East China Sea shelf     

WU ZiYin      JIN XiangLong  CAO ZhenYi  LI JiaBiao  ZHENG YuLong  & SHANG JiHong  Key Laboratory of Submarine Geosciences  State Oceanic Administration  Hangzhou  China  Second Institute of Oceanography 《中国科学:地球科学(英文版)》2010,(1)

Based on the integrated results of multiple data types including MBES (Multi-Beam Echo Sounding) and historical topography maps,the LSR (Linear Sand Ridges) on the ECS (East China Sea) shelf are identified,divided into subareas,and classified.The distribution of sand ridge crests is also established.The strikes of the LSR on the ECS shelf fall in a normal distribution with the center point being 155° azimuth with additional peak points at 125°,130°,140°,and 180° azimuth.The distribution of the ECS shelf san...  相似文献   

开孔沉箱与斜向波作用的理论研究和实验验证   总被引：2，自引：0，他引：2  

滕斌李玉成  刘洪杰 《海洋工程》2004,22(1):37-45

应用透空壁内流体速度与壁两侧的压力差成正比的线性模型,研究了无限多个开孔沉箱在斜向波作用下的反射问题。整个流域被分成无限多个子域,在每个子域内应用特征函数展开法对速度势进行展开。对于沉箱内的波浪运动,根据沉箱位置引入相位差概念。在构造反射波模型时,考虑了结构物几何形状周期性的影响。结果表明,当孔隙系数无限大时,开孔墙前后的速度非常接近,反射系数符合能量守恒定律。在低频入射波作用下,沉箱越短,其反射系数越小,反射系数随着角度的变大而减小。  相似文献   

上地幔各向异性分析中地壳的影响   总被引：7，自引：2，他引：7       下载免费PDF全文

阮爱国  王椿镛  李清河  臧宏 《地球物理学报》2004,47(3):441-448

应用伪谱法研究了地壳各向异性对上地幔各向异性分析的影响. 用几种不同情况下的两层各向异性模型,模拟了全波场,着重分析了不同深度观测点上的剪切波分裂特征. 结果表明,当地壳为各向同性或其各向异性主轴与上地幔重合或相互垂直时,在地壳观测到的快、慢剪切波的偏振方向保持了上地幔中的偏振方向;重合时,快、慢波走时延迟增大;垂直时,走时延迟减小. 当地壳的各向异性主轴与上地幔成一般夹角时,其粒子运动轨迹变得十分复杂,不能直观地识别上地幔各向异性中的快波方向,对走时延迟也有一定的影响. 将常用的两种分析方法应用于对模拟结果的反演,发现当地壳各向异性与上地幔各向异性方向为一般夹角时,反演结果会出现较大的误差或误判. 进而提出解决这一问题的方法,一是综合多种方法的结果;二是由拟合残差或相关系数等值线作进一步的确定.  相似文献   

New Nodosaurid Dinosaur from the Late Cretaceous of Lishui, Zhejiang Province, China   总被引：6，自引：0，他引：6  

LU Junchang JIN Xingsheng SHENG Yiming LI Yihong WANG Guoping Yoichi AZUMA 《《地质学报》英文版》2007,81(3):344-350

A new genus and species of nodosaurid dinosaur： Zhejiangosaurus lishuiensis gen. et sp. nov. is erected herein. It is characterized by the sacrum consisting of at least three true sacral vertebrae, 5 caudal dorsal vertebrae fused to form the presacral rod, wide divergence of long slender preacetabular process of the ilium from the middle line of the body, and the fourth trochanter located at the femoral mid-length.  相似文献   

Analysis on Buckling Performance of Submarine Pipelines During Deepwater Pipe-Laying Operation     

袁林  龚顺风  金伟良  李志刚  赵冬岩 《中国海洋工程》2009,23(2):303-316

Pipes inevitably encounter high ambient pressure and bending moment during the deepwater pipe-laying process,which can lead to elliptical buckling and even deterioration failure.For the safety of pipe-laying operation,available formalas for the pipe stability are established on the basis of the assumption of uniform deformation along the tube length and symmetrical buckling.This method can predict the nonlinear rcsponse of elliptical collapse of steel circular tubes for different ratios of diameter to thickness (D/t) under pure bending or combined bending and external pressure.In these formulas,the strain-displacement relationship is deduced from the nonlinear ring theory,and the Ramberg-Osgood constitutive model is applied to simulate the inelastic material behavior.Meanwhile,the principle of virtual work is adopted to derive the equilibrium equations.A set of equations is solved by the Newton-Raphson method,and the iterative scheme contains nested iteration for the constitutive relation.In order to check the effectiveness of this theoretical method,illustrative examples are presented in this paper.Besides,the numerical simulation is carried out by use of ANSYS.A comparison of the results shows that the theoretical method can provide reasonable prediction for engineering practice.  相似文献   

Phytoplankton pigment patterns and community composition in the northern South China Sea during winter     

翟红昌  宁修仁  唐学玺  郝锵  乐凤凤  乔静 《中国海洋湖沼学报》2011,29(2)

Phytoplankton pigment patterns and community composition were investigated in the northern South China Sea using high-performance liquid chromatography and the CHEMTAX software from February 11 to 23, 2009. We recognized four different vertical distribution patterns of pigments: chlorophyll a (Chl a)-like type, divinyl chlorophyll a (DV Chl a) type, even distribution type, and surface type. The average value of ratios of accessory photo-protective pigments (APP) to accessory photo-synthetic pigments was 0.8...  相似文献   

一种动态绘制无交叉法线坡面线的新算法     

方雷  刘仁义  吕干  杜震洪  姚申君 《测绘学报》2011,40(4):524-530

研究一种动态绘制任何形状的无交叉法线坡面线的新算法,用以克服传统手工绘制复杂坡面线及原有自动化技术的不足。并证明基于＂实交点定理＂及其＂补充定理＂的算法是生成无交叉坡面线的充分条件。进一步说明使用该算法可以动态绘制地形图所需要的任何形状的法线自然（加固）斜坡、崩崖、陡崖、陡石山、堤岸等图式符号。最后,通过三组试验验证算法的有效性,分析算法的特点及影响因素。  相似文献   

Isotope Geochemistry of the Xinchang -Yongjia Silver (Lead-Zinc)Ore Belt in Eastern Zhejiang Province     

Xu Butai  Li Changjiang Zhejiang Institute of Geology  Mineral Resources  Hangzhou  Zhejiangand Chen Haoshou Department of Earth Sciences  Zhejiang U niversity  Hangzhou  Zheyang Liu Xinzhu 《《地质学报》英文版》1995,69(1):69-83

In the Xinchang-Yongjia silver (lead-zinc) ore belt, there mainly occur the large to medium-sized Haoshi, Bamao, Dalingkou and Wubu silver deposits or silver-bearing lead-zinc deposits. On the basis of researches on these typical deposits, the mechanism of leaching-drawing mineralization of Mesozoic geothermal water and the related model are put forward in this paper in the light of the time interval between rock and formation ages as well as hydrogen, oxygen, sulphur and lead isotope geochemical characteristics. The major metallogenic process occurred in volcanic rock layers. The ore-forming fluids are geothermal water coming from meteoric water and circulating at shallow layers. This geothermal water leached and absorbed ore-forming materials from its country rocks during its flowing (such metallogenic elements as silver, lead-zinc and sulphur mainly came from consolidated volcanic rocks), leading to the formation of meso - epithermal silver deposits.  相似文献   

浙江渡船头“伊利石”应属绢云母   总被引：1，自引：0，他引：1  

潘建强 《岩石矿物学杂志》1992,11(4):347-355

渡船头云母状矿物长期以来被称为“伊利石”,近期经过X射线衍射(XRD)、红外光谱(IR)、差热分析(DTA)、电子显微镜(EM)观察及化学组成等研究后显示:这种呈薄鳞片状、粒度很细(一般小于5μm)、结晶度高的矿物,其d(002)=9.95?,为2M多型,出现特征的3625cm~(-1)、3450cm~(-1)、1020cm~(-1)、935cm~(-1)、825cm~(-1)、799cm~(-1)、755cm~(-1)、543cm~(-1)、480cm~(-1)红外吸收和40—70℃、106.4—111.2℃两弱吸热谷及630—670℃强吸热谷;矿物MgO小于0.25%,结构中八面体Mg~(2+)量小于0.03,以Al~(3+)和Fe~(3+)为主,八面体电荷为-0.052—+0.048/O_(10)(OH)_2,K_2O一般大于9%。上述这些均表明,渡船头“伊利石”应属绢云母。  相似文献   

Vertical properties of nutrients and oxygen under tempeuature-salinity structure of the Bering Basin in July 1999     

金明明 《极地研究(英文版)》2002,13(2)

The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [ O2 ] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥ 150 m the [ O2 ] decreases, which is related with both [P] and [N] increasin  相似文献