基于移动GIS的土地集约利用信息采集终端系统     

蒋新源  张美微 《测绘与空间地理信息》2014,(11)

为了解决土地利用的种类复杂、分界不清、分界点精度要求高等问题,研制集GPS,Mobile GIS,PDA,网络通信等先进技术为一体的,能够快速获取土地利用信息的土地集约利用信息采集终端系统,为城市土地集约化利用信息及时、准确的获取提供技术保障。  相似文献   

Axial kinematic response of end‐bearing piles to P waves     

George Anoyatis  Raffaele Di Laora  George Mylonakis 《国际地质力学数值与分析法杂志》2013,37(17):2877-2896

Kinematic pile–soil interaction under vertically impinging seismic P waves is revisited through a novel continuum elastodynamic solution of the Tajimi type. The proposed model simulates the steady‐state kinematic response of a cylindrical end‐bearing pile embedded in a homogeneous viscoelastic soil stratum over a rigid base, subjected to vertically propagating harmonic compressional waves. Closed‐form solutions are obtained for the following: (i) the displacement field in the soil and along the pile; (ii) the kinematic Winkler moduli (i.e., distributed springs and dashpots) along the pile; (iii) equivalent, depth‐independent, Winkler moduli to match the motion at the pile head. The solution for displacements is expressed in terms of dimensionless transfer functions relating the motion of the pile head to the free‐field surface motion and the rock motion. It is shown that (i) a pile foundation may significantly alter (possibly amplify) the vertical seismic excitation transmitted to the base of a structure and (ii) Winkler moduli pertaining to kinematic loading differ from those for inertial loading. Simple approximate expressions for kinematic Winkler moduli are derived for use in applications. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Effect of the duration and direction of storm movement on infiltrating planar flow with full areal coverage     

V. P. Singh 《水文研究》2002,16(7):1479-1511

Using kinematic wave equations, analytical solutions are derived for flow due to a storm moving up or down an infiltrating plane and covering it completely. The storm duration is assumed in two ways. First, the plane is covered everywhere for the same duration by the storm. Second, the plane is covered in a linearly decreasing manner from the beginning of its coverage of the plane to the other end of the plane. By comparing the flow due to this storm with that due to a stationary storm of the same duration, the influence of storm duration, direction and velocity on flow hydrograph is investigated. It is found that storm movement has a pronounced effect on runoff hydrograph. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Upper bound limit analysis using linear finite elements and non‐linear programming     

A. V. Lyamin  S. W. Sloan 《国际地质力学数值与分析法杂志》2002,26(2):181-216

A new method for computing rigorous upper bounds on the limit loads for one‐, two‐ and three‐dimensional continua is described. The formulation is based on linear finite elements, permits kinematically admissible velocity discontinuities at all interelement boundaries, and furnishes a kinematically admissible velocity field by solving a non‐linear programming problem. In the latter, the objective function corresponds to the dissipated power (which is minimized) and the unknowns are subject to linear equality constraints as well as linear and non‐linear inequality constraints. Provided the yield surface is convex, the optimization problem generated by the upper bound method is also convex and can be solved efficiently by applying a two‐stage, quasi‐Newton scheme to the corresponding Kuhn–Tucker optimality conditions. A key advantage of this strategy is that its iteration count is largely independent of the mesh size. Since the formulation permits non‐linear constraints on the unknowns, no linearization of the yield surface is necessary and the modelling of three‐dimensional geometries presents no special difficulties. The utility of the proposed upper bound method is illustrated by applying it to a number of two‐ and three‐dimensional boundary value problems. For a variety of two‐dimensional cases, the new scheme is up to two orders of magnitude faster than an equivalent linear programming scheme which uses yield surface linearization. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

A Complete Formalism For the Inversion of Post-Glacial Rebound Data: Resolving Power Analysis     

J. X. Mitrovica  W. R. Peltier 《Geophysical Journal International》1991,104(2):267-288

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Post-Glacial Relaxation of A Viscously Stratified Compressible Mantle     

J. Wu  D. A. Yuen 《Geophysical Journal International》1991,104(2):331-349

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Kinematic wave solutions for pollutant transport over an infiltrating plane with finite‐period mixing and mixing zone     

V. P. Singh 《水文研究》2002,16(12):2441-2477

Kinematic wave solutions are derived for transport of a conservative non‐point‐source pollutant during a rainfall‐runoff event over an infiltrating plane for two cases: (i) finite‐period mixing and (ii) soil‐mixing zone. Rainfall is assumed to be steady, uniform and finite in duration, and it is assumed to have zero concentration of pollutants. Infiltration is assumed constant in time and space. Prior to the start of rainfall, the pollutant is distributed uniformly over the plane. In the first case, when rainfall occurs, the mixing of pollutant in the runoff water occurs in a finite period of time. In the second case, the chemical concentration is assumed to be a linearly decreasing function of rainfall intensity and overland flow. The solute concentration and discharge are found to depend on the flow characteristics as well as the solute concentration parameters. The characteristics of solute concentration and discharge graphs seem to be similar to those reported in the literature and observed in laboratory experiments. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

pH值对适于页岩气储层的SDBS压裂液性能的影响研究          下载免费PDF全文

冯科玮  曹函  施皆能  吴坤  鲁晓敏 《探矿工程》2015,42(12):13-17

在低渗、低孔隙率页岩气储层压裂改造过程中,压裂液体系的pH值直接影响地层中的造缝、稳缝效果。pH值对阴离子表面活性剂压裂液的粘度、表面张力和页岩膨胀抑制性影响很大。通过改变阴离子表面活性剂的浓度,测定了在不同pH值条件下压裂液体系基本性能的变化。研究表明：SDBS压裂液体系的粘度随着pH值的增加先增大后减小,在pH值=9时达到最大;体系在pH值=5时降低体系表面张力的能力最好;页岩的膨胀量随着pH值的增大逐渐增大,在pH=7时膨胀量最大,且随着pH值的进一步增大,页岩膨胀量先减小后增大,在pH值=9时膨胀量最小;当体系的pH值一定时,SDBS在临界胶束浓度状态能够最大程度抑制页岩的膨胀。从化学微观角度上分析了pH值对SDBS压裂液性能的影响,有利于SDBS压裂液体系配方优化。  相似文献   

东昆仑造山带东段哈图沟–清水泉–沟里韧性剪切带塑性变形及动力学条件研究   总被引：1，自引：0，他引：1  

李小兵  裴先治  陈有炘  刘成军  李佐臣  李瑞保  陈国超  魏博 《大地构造与成矿学》2015,(2)

东昆仑造山带东段哈图沟–清水泉–沟里韧性剪切带记录了多个旋回的造山作用,本文通过对韧性剪切带中石英c轴组构和显微构造特征测试分析,探讨东昆仑造山带东段陆块间俯冲拼合及地壳伸展减薄的形成机制。结果显示,韧性剪切带变形温度介于380~650℃之间,形成环境为中–高绿片岩相到低角闪岩相,剪切带内差异应力值介于173~509 MPa之间,应变速率介于6.93×10–14~1.43×10–8 s–1之间,主体为10–11~10–10 s–1,显示韧性剪切带变形是快速俯冲作用下的产物,越靠近东昆仑造山带东段东昆中断裂带其变形温度、差异应力值及相应的应变速率值越大,表明东昆仑造山带东段韧性剪切变形中心为东昆中断裂带。利用不同方法所计算出的韧性剪切带运动学涡度值,显示韧性剪切带早期瞬时运动学涡度(0.56~1)对应于东昆仑造山带东段东昆南与东昆仑造山带东段东昆北陆块间俯冲的初始阶段,中后期运动学涡度(0.25~0.91)应当对应于东昆南与东昆北陆块间的俯冲碰撞阶段,最晚期的C′瞬时运动学涡度(0.19~0.51)则对应于后造山的伸展阶段。通过石英c轴组构结合其宏微观构造特征,认为东昆中构造带至少经历了3个期次的构造运动,分别为加里东晚期的逆冲兼左行走滑剪切作用、晚海西–印支期的逆冲兼右行走滑剪切作用和燕山早期及之后的脆韧性–脆性的左行走滑剪切作用。  相似文献   

植被分布对小流域产流影响的数值实验          下载免费PDF全文

李妍敏  安翼  刘青泉 《水科学进展》2015,26(2):187-195

基于二维运动波模型,建立了一个适用于小流域场次降雨产汇流过程的动力学模型。通过对典型小流域内不同区域(坡顶、坡中及坡底区域及距离流域出口的远近)种植植被时产流过程的数值模拟,分析了小流域内植被分布对产流过程的影响。结果表明:植被分布及其特性对小流域场次降雨产流有较明显的影响;下游区域种植植被的减水效果和延滞洪峰作用优于上游区域,陡坡区域减水效果优于缓坡区域,且郁闭度越大,这种差别越明显;在该研究条件下,下游区的减水效果可达到上游区的3倍;30%郁闭度条件下减水效果可达10%和20%郁闭度条件下的3倍和1.4倍。  相似文献