基于RS和GIS的城市雾霾与汽车保有量关系研究

近年来我国许多城市雾霾天数增多,雾霾强度增强。本研究利用遥感数据反演获得沈阳市雾霾强度空间分布图。通过分析预测,未来的5年,汽车保有量依然呈现逐年增多的趋势,雾霾强度也将呈现逐年增强的趋势。     

广西昭平大王顶金矿床深部盲矿预测的构造叠加晕模型

广西大王顶金矿为热液型金矿,成矿严格受岩体和构造控制,成矿具有多期多阶段叠加特点。文章总结了该矿床及不同阶段元素组合,在研究单一次成矿形成的原生晕轴向分带和识别出不同成矿阶段形成矿体(晕)在空间上的叠加结构基础上,建立了矿床的构造叠加晕模式,确定了盲矿预测标志,对矿床深部给出了盲矿靶位。     

架空线路年平均雷电闪击频数计算方法探析

分析了规范推荐的架空线路年平均雷击次数计算方法,提出方法中存在截收面积与雷击大地密度对应的雷电流幅值不匹配的问题。为解决该问题,文章以某一具体架空线路为例,介绍了针对全部雷电流幅值,应用积分法计算年平均雷击次数的方法,计算结果与规范推荐方法计算结果的比较说明了积分方法的精密性及结果的合理性。具体的分析、计算方法为：基于电气〖CD*2〗几何模型推导出与雷电流幅值有关的架空线路截收闪电宽度的计算公式,并通过对雷电流幅值频率分布规律的多项式拟合确定任意雷电流幅值的雷击大地密度,任一雷电流幅值对应的截收面积及对应的雷击大地密度的乘积即为该雷电流对应的年平均雷击次数,在该区域雷电流幅值的分布范围内对得到的雷击次数进行积分,即可得到考虑雷电流幅值分布特征的架空线路年平均雷击次数计算结果。     

全球Stokes 漂流的时空分布特征研究

利用海浪模式WWIII(Wave Watch III)2008年的模拟结果对海面Stokes漂流、Stokes输运、Stokes深度以及全球Langmuir数的年平均分布特征和季节平均分布特征分别进行了详细的研究与分析。结果表明,海面Stokes漂流和Stokes输运均呈现高纬度偏大的特征,以南极绕极流海域最为突出。全球大部分海域Stokes漂流影响深度在20 m以内,呈现大洋东部偏大,西部偏小的分布特征。全球大部分海域的混合作用是剪切不稳定性和Langmuir湍效应并存的状态,甚至有些海域是以Langmuir湍效应为主。因此,在进行大尺度的海洋数值模拟时,应该考虑波浪导致的混合效应。     

Numerical Study on the 3-D Complex Characteristics of Flow Around the Hull Structure of TLP

Vortex-induced motion is based on the complex characteristics of the flow around the tension leg platform (TLP) hull. By considering the flow field of the South China Sea and the configuration of the platform, three typical flow velocities and three flow directions are chosen to study the numerical simulation of the flow field characteristics around the TLP hull. Reynolds-averaged Navier–Stokes equations combined with the detached eddy simulation turbulence model are employed in the numerical study. The hydrodynamic coefficients of columns and pontoons, the total drag and lift coefficients of the TLP, the formation and development of the wake, and the vorticity iso-surfaces for different inlet velocities and current directions are discussed in this paper. The average value of the drag coefficient of the upstream columns is considerably larger than that of the downstream columns in the inlet direction of 0°. Although the time history of the lift coefficient demonstrates a “beating” behavior, the plot shows regularity in general. The Strouhal number decreases as the inlet velocity increases from the power spectral density plot at different flow velocities. The mean root values of the lift and drag coefficients of the front column decrease as the current direction increases. Under the symmetrical configuration of 45°, the streamwise force on C4 is the smallest, whereas the transverse force is the largest. The broken vortex conditions in current directions of 22.5° and 45° are more serious than that in the current direction of 0°. In addition, turbulence at the bottom of the TLP becomes stronger when the current direction changes from 0° to 45°. However, a high inlet velocity indicates a large region influenced by the broken vortex and shows the emergence of the wake behind the TLP under the same current angle.     

基于地名互现的城市联系强度研究——以湖北省为例

基于网页地名互现数可以分析地理实体之间的相关性。两个地理位置所对应的地名的互现网页次数越多意味着它们之间的相关性越强。对湖北省各市之间的互现数和拓扑距离进行分析,结果表明:①空间位置相近的市具有更高的互现相似性并有更多的互现网页数;②地名互现的频率具有幂律指数为0.2的距离衰减效应,距离摩擦力要比实际生活中要弱得多。所提出的方法为文本的地名消歧、探究城市联系强度等研究提供了新的思路。     

A general method for defining the number of cycles of repeated loading

In geotechnical engineering designs and safety checks, the number of cycles of repeated loading N is frequently used as a parameter for calculating the response of soil structures under the repeated loading. However, there appears to be a lack of rational methods for calculating N for repeated loadings along general stress paths. A new method for defining N is proposed in this paper, based on the assumption that a yield surface may be identified for the material. It is demonstrated that the proposed method provides a rational and useful means for engineering calculation of soil deformations under repeated loadings. Copyright © 2001 John Wiley & Sons, Ltd.     

NUMBER OF MODES FOR THE SEISMIC DESIGN OF BUILDINGS

The effect of higher modes on the maximum response of buildings subjected to one horizontal component of earthquake ground motion is discussed with the objective of developing better design formulas for use in building design. Ideal buildings of different numbers of storeys and structural systems are defined; their dynamic properties that define higher mode contribution are identified and are shown to be representative of real buildings. Design formulas that give the required number of modes to be used in a dynamic analysis are developed from parametric studies as a function of the admissible error, the number of storeys and the relation between the fundamental period and the corner spectrum period. The recommendations are simple to use and more rational and accurate than the ones actually in use in most seismic design codes.     

裂纹缺陷体积百分数与CT数的关系分析

本文利用混合体的线性衰减系数的线性表示,推导出材料受力环境下,不含杂质时,微裂纹群的出现所带来的密度相对变化量与CT数相对变化量之间的关系式。进一步分析得到了裂纹缺陷体积百分数相对变化量与CT数相对变化量之间的关系式。含单杂质时,得到了裂纹缺陷体积百分数相对变化量与CT数相对变化量的关系式,并且把结论进一步推广到多杂质情形。为后期利用CT进行材料疲劳寿命分析奠定了理论基础。     

矿产资源潜力预测不确定性评价

矿产潜力预测不确定性评价是矿产定量预测的重要环节,其主要研究内容包括未发现矿床数的不确定性、未发现矿床品位、吨位及资源量的不确定性等.本文简要介绍了矿产预测不确定性的主要来源与评价不确定性的途径与方法,并利用模糊集评价了未发现矿床数、品位、吨位及资源量的不确定性.