华北克拉通破坏与岩石圈减薄

古太古代（约4.0 Ga）时地球上可能只有一个超级大陆, 它的岩石圈厚度高达400 km。在早元古代,这个超级大陆减薄、裂解成十几块,每块中心是太古宙岩石,边缘是元古宙岩石,且各块厚度不等（150~350km）。从元古宙之后这些被称之为稳定克拉通的大陆岩石圈就一直漂游在地幔软流圈之上。中国华北地块就是这些克拉通之一,与众不同的是它在中生代时遭受了第二次破坏,岩石圈厚度从古生代时的180~200 km 减少到现今的80~100 km。本文作者从流变学的视角出发,围绕华北克拉通破坏和岩石圈减薄这一核心问题,从     

亚洲中东部岩石圈下层网络状塑性流动与应变场

在板块边缘驱动力的挤压作用下,岩石圈下层（含下地壳和岩石圈地幔）塑性流动网络的共轭角随着变形的增大而由初始的直角变为钝角,因此,可根据共轭角的增量推测应变的大小,并给出该层的应变场,亚洲中东部所含3个塑性流动网络系统的研究表明,岩石圈下层的应变场控制或影响着上部地壳的构造变形和地形起伏,表现在应变“凸锋~”与地形凸峰之间的相互对应以及“稳定”块体的低应变效应和应变的波动传播,网络共轭角推测应变的方法为认识板内应变场和构造变形提供了新的途径。     

Limited flow characteristics of sand with fines under cyclic loading

Experimental studies on a sand with a well-graded low plasticity fines were conducted to study a number of issues related to limited flow. Cyclic behaviour in relation to instability and limited flow are compared with corresponding monotonic behaviour. A single set of rules for a range of fines contents was proposed to correlate cyclic and monotonic behaviour.     

弯道超高法在泥石流流速计算中的应用——以四川省汶川县G317国道磨子沟泥石流为例

选取四川省汶川至马尔康公路线的磨子沟作为试验对象,采用弯道超高法推算其泥石流流速。进而可以计算出该次泥石流的平均流量,为公路的改建工程提供设计依据。经过实地调查,用此方法计算磨子沟2005年8月17日暴发的泥石流流速为4.4m/s。同其他流速方法计算的结果相比较,前者值偏大,且偏向于工程安全值。弯道超高法可以解决泥石流观测的局限性和泥石流发生的不可重复性。此方法简便易行,对泥石流防治工程具有一定的实用价值。     

局地雹暴环境气流的演变特征

通过甘肃永登、岷县防雹试验基地1979~1987年获取的1 d 4次无线电探空资料,对照地面实况,对强冰雹、弱冰雹、雷雨、阵雨、阴天、晴天6类天气的高空风进行分析研究,发现强雹暴在降雹前期低空风向切变、中空风速切变、高空急流等与其它类型天气比较具有显著的差异,这对于预报雹暴天气和雹暴形成机制的研究具有指示意义。     

Analysis of interaction between ship bottom air cavity and boundary layer

The successful designs of hulls for ships employing drag reduction by air bottom cavitation have been based on solutions of inverse problems of the theory of ideal incompressible fluid. However, prediction of the drag reduction ratio, the air demand by ventilated cavities and the cavity impact on the hull–propeller interaction is impossible in the framework of this theory because all mentioned characteristics depend on interaction of air cavities with the ship boundary layers. Because the known CFD tools are not fitted to ventilated cavitation at low Froude numbers, an analysis of this interaction requires a novel flow model. This model includes the incompressible air flow in the ventilated cavity, the compressible flow of a water–air mixture in the boundary layer on cavities and downstream of them and the curl-free incompressible outer water flow. The provided 2D computations employing this model allows for explanations of the earlier observed effects and for prediction of the air demand by ventilated cavities. The computed velocity profiles downstream of cavities are in the accordance with the available experimental data.     

Adaptive Observer Based Backstepping Controller Design for Dynamic Ship Positioning

Modified adaptive observer based backstepping control system for dynamic positioning of ship is proposed. As an improvement, the adaptive observer takes the first-order wave frequency model and the bias term which represent the slowly varying environmental disturbances and the unmodeled dynamics. Thus, the wave-frequency motions are filtered out, and only the reconstructed low-frequency motions are sent as inputs of the controller. Furthermore, as the ship dynamics parameters are unknown, the adaptive estimation law is designed for both the unknown ship dynamics and the unmeasured state variables. Based on the estimated states and parameters, backstepping controller considering the integral action is designed. Global exponential stability (GES) for the total system is proved using Lyapunov direct method. Simulation results show a good performance of the observer and control system.     

运用H、O同位素分析石阡地区地热水来源

通过对贵州省石阡地区地热水、冷泉及河流的地热地质条件、水化学成分及氢氧同位素分析,对该地区的地热水、冷泉及河流的水化学特征、来源及石阡地区的补给模式进行了研究.温泉水属于低中矿化度的弱碱性水;温泉群中阳离子以Ca2+、Mg2+为主,阴离子以SO42-和HCO3-为主,研究区水化学类型主要为HCO3-Ca和SO4.HCO...     

交通流量分析与实时最优控制

通过将车流量的增大或减小转化为路长权重的变化。将交通流量的动态问题转化为静态问题，用解决最短路问题的Dijkstra方法，给出交通流量实时最优控制的可行性模型及其有效算法。     

基于空间面板计量模型的雾霾对中国城市旅游流影响的空间效应

以中国342个市域单元为研究对象,借助双变量LISA模型、空间面板杜宾模型等方法,探究了1998-2016年雾霾与中国城市旅游流的空间关联特征,分析了雾霾对旅游流的影响及其空间溢出效应。结果表明,在中国雾霾PM_2.5与城市旅游流有东高西低的分布特点,在胡焕庸线两侧的空间分布呈现出与地形和城市发展等因素的空间耦合性;雾霾与城市旅游流（含国内和入境旅游流）均表现出显著的空间集聚和空间依赖特征,雾霾污染对旅游流产生明显的影响并形成相应的空间效应;雾霾对旅游流的抑制区域在不断扩大,H-L型城市数量的增加、L-H型集聚区的片状扩张和华北、华中地区的L-H型集聚的“空心化”现象均表明旅游流具有低雾霾指向性;雾霾污染与旅游流的倒“U”型曲线关系表明经典的EKC假说对中国城市旅游流同样适用,且雾霾污染的显著负向影响主要存在于入境旅游方面;雾霾和旅游流均具有明显的正向空间溢出效应,将雾霾治理同经济发展、对外联系、旅游开发、生态保护和交通建设等因素结合起来进行综合治理,才能为旅游发展创造美好的环境,实现国际、国内旅游健康、协调、可持续的高质量发展。