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21.
立足样品测试数据,利用空间分析、空间插值、地质统计以及景观生态学方法,深入分析了深圳大鹏湾表层沉积物碎屑矿物的空间分布特征,并使用球状模型对相应半变异函数进行理论建模。结果表明,碎屑矿物分布的Hurst分维数为0.28~0.97,空间几何分维数为1.03~1.72;Moran Ⅰ型空间自相关系数-0.15~0.53。在此基础上,以等值线分布所包围范围作为划分尺度,以Shannon-Wiener信息指数作为度量,得到的矿物分布所反映出的信息量或者富集程度指数为0.88~1.85。 相似文献
22.
本文介绍了一种数字测深仪的接收机的具体设计,其特点是低噪声、增益程序控制,可以输出高质量的回波信号。稍加调整,即可用作其它声纳的接收机。 相似文献
23.
Moo Hee Kang Hyun-Chul Han Hyesu Yun Gee Soo Kong Kyong O. Kim Youn Soo Lee 《Marine Geophysical Researches》2007,28(3):257-269
A seamount chain with an approximately WNW trend is observed in the northeastern Ulleung Basin. It has been argued that these
seamounts, including two islands called Ulleung and Dok islands, were formed by a hotspot process or by ridge related volcanism.
Many geological and geophysical studies have been done for all the seamounts and islands in the chain except Anyongbok Seamount,
which is close to the proposed spreading ridge. We first report morphological characteristics, sediment distribution patterns,
and the crustal thickness of Anyongbok Seamount using multibeam bathymetry data, seismic reflection profiles, and 3D gravity
modeling. The morphology of Anyongbok Seamount shows a cone shaped feature and is characterized by the development of many
flank cones and flank rift zones. The estimated surface volume is about 60 km3, and implies that the seamount is smaller than the other seamounts in the chain. No sediments have been observed on the seamount
except the lower slope, which is covered by more than 1,000 m of strata. The crustal structure obtained from a 3D gravity
modeling (GFR = 3.11, SD 3.82 = mGal) suggests that the seamount was formed around the boundary of the Ulleung Plateau and
the Ulleung Basin, and the estimated crustal thickness is about 20 km, which is a little thicker than other nearby seamounts
distributed along the northeastern boundary of the Ulleung Basin. This significant crustal thickness also implies that Anyongbok
Seamount might not be related to ridge volcanism. 相似文献
24.
-The hydrodynamic forces on a smooth inclined circular cylinder exposed to oscillating flow were experimentally investigated at Reynolds number (Re) in the range 40000-200000 and Keulegan-Capenter number (KC) in the interval from 5-40. In the test, Re number and KC number were varied systematically. The inertia force coefficient (Cu) and the drag force coefficient (CD) in Morison equation were determined from the measured loads and the water particle kinematics. In this analysis a modified form of Morison equation was used since it uses the normal velocity and acceleration. Thus, the applicability of the Cross Flow Principle was assumed. This principle, simply stated, is as follows: the force acting in the direction normal to the axis of a cylinder placed at some oblique angle with the direction of flow is expressed in terms of the normal component of flow only, and the axial component is disregarded. Both the total in-line force coefficient (CF) and transverse force (lift) coefficient (Cf) were analyzed 相似文献
25.
K. S. Jeong J. K. Kang K. Y. Lee H. S. Jung S. B. Chi S. J. Ahn 《Geo-Marine Letters》1996,16(2):123-131
In the northwestern margin of the Clarion and Clipperton fracture zones, manganese nodules are latitudinally variable in character, resulting from the progressive (re)generation of nodules since the Oligocene as the Pacific Plate migrates northwestward beneath the equatorial production zone. Complemented by the surface water productivity, bottom current activities have concentrated nodules in the Oligocene to Miocene siliceous clay. Resedimentation processes on nodules form three types of nodules with concentric structures and 10 Å-manganaterich bottoms, by periodically causing the diagenetic growth of nodules within the topmost sediment layer. 相似文献
26.
白云凹陷地球物理场及深部结构特征 总被引:13,自引:2,他引:13
珠江口盆地白云凹陷是南海最具代表性的第三系深水陆坡沉积区。以穿过白云凹陷中部的一条深反射地震剖面(14s)为研究基础,采用综合地球物理研究方法分析了该区地球物理场特征,根据重力异常平面等值线勾画了白云凹陷的形态,并提取该测线相对应的重磁剖面数据,利用重磁资料和地震剖面进行了综合反演。以深剖面地震资料建立了地质模型,利用所得的重力数据进行了研究深部结构的正演拟合,实测与计算值拟合较好,支持中生代俯冲洋壳存在的观点;同时结合地震资料对深部结构进行了分析,该区莫霍面由陆向海抬升,呈阶梯状变化,地壳厚度逐渐减薄,具有大陆边缘陆壳向洋壳过渡的特征。根据地质模型还进行了变密度综合反演拟合来分析基底岩性特征,该区基底主要为中酸性岩浆岩,部分为变质岩和基性火山岩,岩石密度由陆向洋逐渐减小,磁性体分布不均。 相似文献
27.
为给单环刺 (U.unicinctus)的苗种生产提供有效的基础资料 ,本文研究了水温对单环刺胚胎发育的影响。结果表明 :单环刺各胚胎发育期的发育速度 (h)随水温 (T)升高而加快 ,有明显的正相关性。求得胚胎发育的生物学零度为平均 2℃。不同水温条件下 ,各期幼虫期的存活率以2 0℃为最高 ,培育水温高于或低于 2 0℃时生存率逐渐降低。幼虫培育适宜温度为 15~ 2 0℃。 相似文献
28.
29.
This study uses a comparative approach to examine responses of marine ecosystems to climatic regime shifts. The three seas surrounding the Korean peninsula, the Japan/East Sea, the East China Sea and the Yellow Sea represent three contiguous but distinct ecosystems. Sampling has been carried out by the National Fisheries Research and Development Institute of South Korea since 1965, using the same methods in all three seas. Sampling was generally synoptic. Amplitude time series of 1st EOF modes for temperature, salinity, zooplankton biomass and concentrations of four major zooplankton taxa were used to determine whether the three marine ecosystems respond in a similar manner to climate variations. Temporal patterns of the variables were strongly similar among the three seas at decadal time scales, but very weakly similar at interannual scales. All three seas responded to a climatic regime shift that occurred in 1989. Temperature, zooplankton biomass and copepod concentrations increased in the late 1980s or early 1990s in all three seas. Concentrations of amphipods, chaetognaths and euphausiids also increased in the Japan/East Sea and the East China Sea, but not the Yellow Sea. The Yellow Sea ecosystem differs strongly from the other two seas, and water exchange between the Yellow Sea and the East China Sea is much weaker than that between the East China Sea and Japan/East Sea. Spatial patterns of zooplankton determined by the EOF analysis were closely related to currents and fronts in each of the three seas. 相似文献
30.