广西气象台影视广告竞争性环境分析

采用美国著名战略学者——迈克尔.波特的五种竞争力量模型分析方法,通过对身处媒体巨变中的广西气象台影视广告环境的竞争性进行分析,提出了竞争对策。     

含裂隙煤层的地震记录模拟

采用线性滑移(Linear Slip Deformation)裂隙介质模型、各向异性弹性波模拟方法,对含裂隙煤层进行了2D2C(二维二分量)单炮记录模拟与分析。结果表明:煤层含裂隙后与不含裂隙时相比,反射时差的变化已不足以识别,但由于波速的改变会使煤层顶底界面的波阻抗发生变化,从而引起波的动力学特征的改变,AVO现象尤其明显。当裂隙为非垂直时,炮点两侧的反射波能量和振幅出现不对称现象。x分量和z分量的特征明显不同,转换波主要记录在x分量上,横波在x分量上有不可忽视的能量。因此,应用各向异性理论、利用多分量转换波研究煤层裂隙的特征是可能的。     

基于社交媒体签到数据的城市居民暴雨洪涝响应时空分析

暴雨洪涝等小型地域性气候灾害给城市韧性带来挑战。以南京暴雨洪涝为例,通过挖掘新浪微博签到数据,构建公众感知指数和公众情绪指数,分析居民对暴雨洪涝响应的时空格局。在时间维度上,居民对暴雨洪涝的响应主要集中在暴雨洪涝期,并随灾害的严重程度而变化;在暴雨洪涝期内,居民在社交媒体上对暴雨洪涝的响应集中在早、晚高峰。在空间维度上,居民对暴雨洪涝的响应集中在主城区和3个新市区;重要交通基础枢纽地区和低海拔、经历快速城市化的新市区的居民对暴雨洪涝担忧程度更高。时空分析表明,暴雨洪涝对居民的交通出行影响最明显。基于时空间分析,最后从硬件和软件设施上为提升暴雨洪涝的城市韧性提供相关政策建议。     

A three‐phase model for unsaturated soils

A comprehensive framework to define the constitutive behaviour of unsaturated soils is developed within the theory of mixtures applied to three‐phase porous media. Each of the three phases is endowed with its own strain and stress. Elastic and elastic–plastic constitutive equations are developed. Particular emphasis is laid on the interactions between the phases both in the elastic and plastic regimes. Nevertheless, the clear structure of the constitutive equations requires a minimal number of material parameters. Their identification is provided: in particular, it incorporates directly the soil–water characteristic curve. Crucial to the formulation is an appropriate definition of the effective stress. The coupled influence of this effective stress and of suction makes it possible to describe qualitatively many of the characteristic features observed in experiments, e.g. for normally consolidated soils, a plastic behaviour up to air entry followed by an elastic behaviour at increasing suctions, and, on the way back, an elastic behaviour, unless compression is applied in which case plastic collapse occurs. Copyright © 2000 John Wiley & Sons, Ltd.     

A pore-scale numerical model for flow through porous media

A pore-scale numerical model based on Smoothed Particle Hydrodynamics (SPH) is described for modelling fluid flow phenomena in porous media. Originally developed for astrophysics applications, SPH is extended to model incompressible flows of low Reynolds number as encountered in groundwater flow systems. In this paper, an overview of SPH is provided and the required modifications for modelling flow through porous media are described, including treatment of viscosity, equation of state, and no-slip boundary conditions. The performance of the model is demonstrated for two-dimensional flow through idealized porous media composed of spatially periodic square and hexagonal arrays of cylinders. The results are in close agreement with solutions obtained using the finite element method and published solutions in the literature. Copyright © 1999 John Wiley & Sons, Ltd.     

环肋圆柱壳体在水下冲击波作用下的动力弹塑性屈曲

本文以加肋圆柱壳体为对象建立力学模型，在水下爆炸产生的冲击波作用下，考虑流体与结构的耦合效应，研究加肋圆柱壳体的弹塑性失稳变形量及动力响应特性。数值分析显示出的最终变形形状和压力变化过程与实验资料一致的     

含气介质临界点、流体和骨架弹性参数的线性数值计算方法(英文)

临界孔隙度及其孔隙介质的研究均为测试分析的实验方法,如何运用数值计算方法求取孔隙流体介质临界点、流体和骨架的弹性参数是备受关注的课题。本文提出了求取临界点、流体和骨架弹性参数的数值计算公式及方法,并结合含气样品测试数据实现了这种数值计算。首先,基于孔隙度≯为白变量,而密度ρ,密度与横波速度平方的乘积ρVs^2和密度与纵波速度平方的乘积ρVp^2均为函数的三个线性方程,从每个线性方程中的两个系数的有机组合得到求取有关弹性参的线性数值计算公式。然后,详细阐述了数值计算的步骤和方法以及需要注意的问题,把室内含气砂岩数的线性数值计算公式。然后,详细阐述了数值计算的步骤和方法以及需要注意的问题,把室内含气砂岩样品测试的整体介质密度、纵波速度和横波速度作为数值计算的输入数据,求取了临界点和流体及骨架共计11个弹性参数的具体数值。通过数学方法的计算数据与实验方法的测试数据的比较分析,表明了本文数值计算公式的正确性和实现方法的有效性。本文提出的求取含气介质临界点、流体和骨架弹性参数的“数值计算公式及方法”含义清晰且形式简洁,为孔隙流体介质的数值计算分析和流体属性研究提供了可能的新方法。     

VOODOO,ZOMBIES, AND MERMAIDS: U.S. NEWSPAPER COVERAGE OF HAITI*

ABSTRACT. Newspaper articles in the United States paint a picture of Haiti as a failed state, the poorest country in the Western Hemisphere. These articles place the blame of the country's problems entirely on Haiti itself, with little regard for the outside forces that also contributed to the country's present‐day state. This study is a critical geopolitical analysis of Haitian representation in U.S. newspapers. I empirically examine a year's worth of articles from 2004 written in five major U.S. newspapers. From these articles I analyze both the words used to describe Haiti and the emerging media frames. Critical studies have shown that representation in the media can greatly impact the conventional wisdom surrounding a place and legitimize social inequalities. By understanding the images used to describe Haiti, I hope to develop a means of rethinking popular perceptions of the country. I argue that only then can the problems of Haiti be more effectively addressed and a new dialogue created, one that encompasses the entire story of this Caribbean country.