库水位涨落条件下滑坡地下水渗流场动态特征

为探讨库水位升降对滑坡地下水的动态作用机理,以三峡库区石榴树包滑坡为例,采用有限元法,模拟了5种工况下库水位升降速率及不同渗透系数下滑坡体内地下水的暂态渗流场特征.研究结果表明:滑坡体内地下水渗流浸润线受水位升降速率与坡体渗透系数的共同影响;库水位上升条件下,当滑体渗透系数大于1×10-4 m/s,且水位上升速率小于渗透系数时,滑坡体表现为蓄水同步型.库水位下降条件下,当滑体渗透系数小于1×10-6 m/s时,库水位发生骤降;渗透系数介于1×10-4~1×10-5 m/s之间时,库水位表现为缓降;渗透系数大于1×10-4 m/s时,渗流浸润线与库水位保持同步下降.      

Modified QUICK schemes for 3D advection-diffusion equation of pollutants on unstructured grids

In the framework of finite volume method (FVM), two modified schemes of quadratic upstream interpolation for convective kinematics (QUICK), namely quasi-QUICK (Q-QUICK) and normal quasi-QUICK (NQ-QUICK), for improving the precision of convective flux approximation are verified in 3D unsteady advection-diffusion equation of pollutants on unstructured grids. The constructed auxiliary nodes for Q-QUICK or NQQUICK are composed of two neighboring nodes plus the next upwind node; the later node is generated from intersection of the line of current neighboring nodes and their corresponding interfaces. The numerical results show that Q-QUICK and NQ-QUICK overwhelm central differencing scheme (CDS) in computational accuracy and behave similar numerical stability to upwind difference scheme (UDS), hybrid differencing scheme (HDS) and power difference scheme (PDS) after applying the deferred correction method. Their corresponding CPU time is approximately equivalent to that of traditional difference schemes. In addition, their abilities for adapting high grid deformation are robust. It is so promising to apply the suggested schemes to simulate pollutant transportation on arbitrary 3D natural boundary in the hydraulic or environmental engineering.     

广西沿海高速公路石湾枢纽互通改扩建方案研究

对广西沿海高速公路改扩建四期工程(钦州至北海)高速公路扩建项目中的枢纽互通立交方案进行了研究,并对各方案的优缺点进行了全面比较,提出了改扩建的推荐方案。     

氧空位对钴掺杂氧化锌稀磁半导体电子结构的影响

通过第一性原理计算对Co掺杂ZnO稀磁半导体的磁学性质和电子结构进行了研究,对氧空位甘现在不同位置时体系总能进行计算,证实氧空位更容易在Co原子附近生成,电子结构计算表明Co-3d自旋电子在费米能级附近产生了自旋极化现象,提供局域磁矩;通过研究两个Co原子掺杂ZnO体系的电子结构,证实铁磁性的产生是两个co原子耦合的结果,氧原子起到了一定的调制作用．     

同时带送货和取货的农村邮政车辆运输优化分析

全球范围内的物流产业飞速发展,现代农村物流是现代物流的一个重要分支。中国邮政具有其他物流企业所不具备的优势,中国农村物流的发展必须依赖中国邮政这种完善的物流基础设施才得以取得快速的发展,才能满足日益增长的农村运输量的需求。在研究农村邮政车辆运输优化问题时,把研究重点放在车辆路径的优化选择上,这样可以使得车辆总的运输距离最小,进而使农户的购买费用和涉农企业的成本最小。     

基于ILAS数字图书馆异地备份研究与实现

研究了数据备份的方法和主要备份技术,并结合武汉船舶职业技术学院图书馆的实际情况,介绍了基于UNIX网络环境数字图书馆动态数据的安全问题,分析了ILAS数字图书馆异地备份技术的实现。     

无填料振冲法在埃及塞得东港集装箱码头中的应用

无填料振冲法在埃及塞得东港集装箱码头二期地基处理工程中得以应用。对不同振冲间距的处理效果进行了CPT对比试验,在选定施工参数后在大范围施工进行应用并对比施工前后CPT数据验证处理效果。介绍无填料振冲法在码头工程中的适用条件和取得的良好加固效果和经济效益,其施工参数和经验可以在相同地质情况下的类似工程中推广用。     

外压作用下带初挠度加筋圆柱壳极限载荷及变形研究

加筋圆柱壳的承压分析包含极限载荷和后屈曲变形,对这二者进行准确预报是加筋圆柱壳在建造完工后的重要一环。通过实测初挠度建立了反映加筋圆柱壳真实几何形状的有限元模型,在ABAQUS中使用弧长法获得了加筋圆柱壳在外部静水压作用下的极限载荷值,采用弧长与Dynamic/explicit相结合的途径模拟了加筋圆柱壳在外压作用下的后屈曲过程,并获得最终变形。通过与试验结果对比,得出上述数值方法准确可靠,计算结果更加符合客观实际,可以推广到工程应用中。     

Four-degree-of-freedom course stability of an air cushion vehicle

A four-degree-of-freedom mathematical model was established to investigate the course stability of an air cushion vehicle (ACV). The forces of aerodynamic,propeller and rudder were obtained by wind tunnel experiments. A series of constrained model experiments with horizontal-planar-motion-mechanism (HPMM) were conducted to determine the hydrodynamics. The ACV's course stability was analyzed by using Hurwitz deter-mination method with differential equation of perturbation,and the four-degree-of-freedom cours...     

Research of interaction force coefficients based on model test in loading condition

It is very difficult,for the component-type ship mathematical model,to estimate the interaction force coefficients among the hull,propeller and rudder. Some coefficients such as wake fraction and flow straightening coefficient were studied from the model tests in diffierent loading conditions and the normal force of rudder was tested in captive model tests to obtain the coefficients. From these results of the tests,the flow straightening coefficients increase with the increase of trims or drafts. Similarly,...