南黄海盆地中部隆起的形成与演化

南黄海盆地是在前震旦系克拉通基础上发育的中、古生界海相与中、新生界陆相多旋回叠合盆地。通过地震资料解释,结合邻区钻井与区域地质资料,对南黄海盆地中部隆起中、古生代地层及其形成演化进行了研究,结果表明,南黄海盆地中部隆起沉积了较全的中、古生界海相地层,发育第四系—新近系、中—下三叠统青龙组、上二叠统、下二叠统—上泥盆统、中—下志留统,奥陶系—震旦系和前震旦系变质岩系等7套地震地质层序;主要经历了前震旦纪基底形成、震旦纪—早古生代克拉通发育、晚古生代—中三叠世稳定台地—陆内裂陷、晚三叠世—古近纪形成与抬升剥蚀及新近纪-第四纪坳陷沉降5个阶段。     

On accretion flow penetration of magnetospheres

We address the problem of plasma penetration of astrophysical magnetospheres, an important issue in a wide variety of contexts, ranging from accretion in cataclysmic variables to flows in protostellar systems. We point out that under well-defined conditions, penetration can occur without any turbulent mixing (driven, for example, by Rayleigh–Taylor or Kelvin–Helmholtz instabilities) caused by charge polarization effects, if the inflowing plasma is bounded in the direction transverse to both the flow velocity and the magnetic field. Depolarization effects limit the penetration depth, which nevertheless can, under specific circumstances, be comparable to the size of the magnetosphere. We discuss the effect of ambient medium on plasma propagation across the stellar magnetic field and determine the criteria for deep magnetosphere penetration. We show that, under conditions appropriate to magnetized white dwarfs in AM Her type cataclysmic variables, charge polarization effects can lead to deep penetration of the magnetosphere.     

Study on scattering wave force of horizontal and vertical plate type breakwaters

The interaction between wave and horizontal and vertical plates is investigated by the boundary element method,and the relations of wave exciting force with plate thickness,submergence and length are obtained.It is found that:1) The efficient wave exciting force exists while plate submergence is less than 0.5 m,and the plate is very thin with order O(0.005 m).2) The maximum heave wave exciting force exists,and it is the main factor for surface and submerged horizontal plate while the roll force can be ignored.3) The maximum sway wave exciting force exists,it is the main factor for surface or submerged vertical plate,and the roll force is about 20 times of horizontal plate.     

防波堤的人工神经网络Monte Carlo法可靠性分析

防波堤建设费用巨大,且一旦遭到破坏,后果甚为严重,因此,如何准确地计算防波堤的可靠性意义重大.随着人工神经网络理论的快速发展,人工神经网络方法在结构可靠性分析中的应用逐渐得到重视.基于神经网络的Monte Carlo法计算直立式防波堤的可靠性,概率意义明确.以秦皇岛典型直立堤为算例,采用基于神经网络的Monte Carlo法对直立式防波堤进行可靠性分析时,将直立堤滑动破坏和倾覆破坏的极限状态方程中的所有参数均作为变量处理,并将计算结果与Monte Carlo模拟的直接抽样法、重要抽样法以及独立变量JC法的计算结果进行对比.结果表明:基于神经网络的Monte Carlo法和Monte Carlo模拟的直接抽样法、重要抽样法计算结果相近,而比独立变量JC法的计算结果略低.     

Current Nature of the Kuroshio in the Vicinity of the Kii Peninsula

The Kuroshio flows very close to Cape Shionomisaki when it takes a straight path. The detailed observations of the Kuroshio were made both on board the R/V Seisui-maru of Mie University and on board the R/V Wakayama of the Wakayama Prefectural Fisheries Experimental Station on June 11–14, 1996. It was confirmed that the current zone of the Kuroshio touches the coast and bottom slope just off Cape Shionomiaki, and that the coastal water to the east of the cape was completely separated from that to the west. The relatively high sea level difference between Kushimoto and Uragami could be caused by this separation of the coastal waters when the Kuroshio takes a straight path. This flow is rather curious, as the geostrophic flow, which has a barotropic nature and touches the bottom, would be constrained to follow bottom contours due to the vorticity conservation law. The reason why the Kuroshio leaves the bottom slope to the east of Cape Shionomisaki is attributed to the high curvature of the bottom contours there: if the current were to follow the contours, the centrifugal term in the equation of motion would become large and comparablee to the Coriolis (or pressure gradient) term, and the geostrophic balance would be destroyed. This creates a current-shadow zone just to the east of the cape. As the reason why the current zone of the Kuroshio intrudes into the coastal region to the west of the cape, it is suggested that the Kii Bifurcation Current off the southwest coast of the Kii Peninsula, which is usually found when the Kuroshio takes the straight path, has the effect of drawing the Kuroshio water into the coastal region. The sea level difference between Kushimoto and Uragami is often used to monitor the flow pattern of the Kuroshio near the Kii Peninsula. It should be noted that Uragami is located in the current shadow zone, while Kushimoto lies in the region where the offshore Kuroshio water intrudes into the coastal region. The resulting large sea level difference indicates that the Kuroshio is flowing along the straight path.     

中国及其邻区周围板块作用力的研究

给出了如何根据观测的应力方向,利用平滑方法处理为在规则格点上均匀分布的数据的过程,并利用新编的中国及其邻区地震震源机制解推断的观测应力方向,反演了周围板块作用力的相对大小．结果表明,在周围三大板块中,以印度板块的作用力最大;其次是太平洋板块;而在菲律宾海板块边界上,作用力大小差异较大,其中又以与台湾相邻的边界段受力最大,琉球岛弧受力最小．     

海洋立管试验支座设计及其对涡激振动影响研究

针对大长细比顶张力立管内外流共同作用时涡激振动的试验研究,考虑端部铰接和固接两种边界条件,设计了可施加张力和内流的铰接支座和固接支座,并对两种支座进行数值模拟及受力分析,最后用于深水立管的涡激振动试验。立管模型材料采用6.2 m长铜管,外径20 mm,壁厚1.5 mm,分别支撑在铰接支座和固接支座上,施加不同的顶部张力、外流流速和内流流速。通过在立管表面粘贴光纤光栅应变计获得动态应变数据,分别从动态响应幅值、频率等方面对不同边界条件立管的试验数据进行对比分析,得出在顶张力、内流速相同的情况下,外流速相等时两端铰接立管的振动幅值大于两端固接立管,随着外流速的增加,两端铰接立管比两端固接立管率先发生锁振现象。     

塔里木河干流土地利用/覆盖变化的社会经济驱动力分析

土地利用/覆盖变化的驱动力分析是土地利用/覆盖研究的一个主要核心内容。利用相关分析和主成分分析,探讨土地利用变化的社会经济驱动力。在驱动力分析的基础上,建立人口因素与土地利用程度的分异模型,并通过干扰度指数的计算,分析人类活动对不同景观类型的干扰强度。研究结果表明：研究区土地利用变化的主要社会经济驱动力为：人口因素、经济因素、技术因素和区域社会经济发展程度等。人类活动对建设用地的干扰强度最大,其次是林地、耕地和水域,而对于其他景观类型的干扰度则不甚明显。人口密度与土地利用程度的分异模型适用于分析现阶段人口密度与土地利用程度之间的关系,而且还可以通过预测未来人口变化状况进行土地利用程度的预测。     

清代东北地区土地开发及其动因分析

论述了清代东北地区土地开发过程、特点和趋动因子。指出封禁时期土地开发主要集中于辽河流域及辽西地区,吉、黑两地只有零星开发,总的呈现一派大荒景象。开禁后,先后在奉天、吉林、黑龙江进行了大面积的放垦。大规模的移民和高速度的土地开发世所少见。最后分析了影响东北地区土地开发的主要趋动因子,指出巨大的人口压力、连年的大灾荒以及清朝政府的土地开发政策是造成清代晚期东北地区大规模移民和高速度土地开发的重要原因。     

基于GPS速度场的云南地壳应力积累特征分析

利用2009~2015年的GPS水平运动速度场数据,解算云南地区的地壳应变场,在红河断裂与曲江断裂选取两个GPS剖面,计算并分析两个断裂的应变积累特征。结果显示：1）红河、曲江、小江等多个主要断裂应变场存在张、压交替的时空演化特征,近期曲江断裂南段表现为东西向拉张,红河断裂北段东西向拉张量值较大,约12.0×10-8/a,云南南部主要表现为NNE向的压性变化;2）从GPS剖面看,红河、曲江断裂在两个方向上均显示右旋走滑与拉张的变化特征,从量值上看,红河断裂北段运动速率较大,约8.90 mm/a。