云宵县5月暴雨客观预报模型     

赖惠贞陈荣平  朱昌桂廖燕珍 《河南气象》2004,(3):9-11

采用文献[1]提出的技术模型，研制了云宵县5月暴雨预报方法，建立了4个因子结构简单而天气学意义明了的客观预报模型。经2000～2003年试用，这种基于场量因子的预报模型，未漏报，严格评定的准确率为67％，明显优于主观预报。  相似文献   

渭河河谷甘肃段水资源承载能力分析   总被引：1，自引：0，他引：1  

王有权 《地下水》2004,26(2):137-139

本文在论述渭河河谷甘肃段水资源分布特点及现状利用量和承载量的基础上,分析了水资源的承栽能力,认为区内水资源最佳承载量是355万人,355亿元工业产值和248.5万亩的可灌高效农田.据此提出了城市发展规模的大小,目的是供地方政府规划参考.  相似文献   

长春市城市土壤中重金属元素的积累及其微生物特性研究   总被引：10，自引：2，他引：10  

刘乃瑜  马小凡  谢忠雷  郭平 《吉林大学学报(地球科学版)》2004,(Z1)

由于人为活动的影响,长春市城市土壤中重金属Cu、Zn、Pb、Cd已有了显著积累。在重金属的胁迫下,土壤微生物特征发生了明显变化,微生物代谢活动明显增强,但微生物生物量却有较大的降低。微生物生理生态参数土壤微生物量碳与总有机碳的比值(Cmic/Corg)和代谢商QCO2(微生物呼吸作用强度与微生物量碳的比值)变化异常。研究表明,微生物特性可作为城市土壤环境中重金属含量变异的有效指标。  相似文献   

Fundamental study on the response characteristics of drivers during an earthquake based on driving simulator experiments     

Yoshihisa Maruyama  Fumio Yamazaki 《地震工程与结构动力学》2004,33(6):775-792

After the 1995 Kobe earthquake, the expressway structures in Japan were retrofitted and they will not now be seriously damaged under a certain level of strong earthquake motion. However, the stability of a moving vehicle has not been investigated yet. It has been reported that drivers feel seismically induced vibrations, especially in the transverse direction of vehicles. Owing to this phenomenon, drivers have some difficulty in controlling the vehicles during strong shaking. For further safety promotion of the expressway networks, it is important to understand the drivers' reactions to seismic motion. The present authors have performed a series of seismic response analyses of a moving vehicle to investigate its response characteristics based on numerical simulation. However, the responses of the driver were not considered in the simulation process. In order to investigate the drivers' reactions during an earthquake, a series of virtual tests were conducted using a driving simulator. This driving simulator has six servomotor‐powered electric actuators that control its motions. Several types of tests were carried out for different examinees to investigate drivers' responses while controlling the simulator under seismic motion. The results of this study showed that a larger response time lag to strong shaking and over turning of the steering wheel may shift the vehicle into the next lane. According to this finding, trafficaccidents could possibly occur under strong ground shaking in the case of heavy traffic. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Dynamic response of partially sealed circular tunnel in viscoelastic saturated soil   总被引：1，自引：0，他引：1  

Kang-he Xie  Gan-bin Liu  Zu-yuan Shi 《Soil Dynamics and Earthquake Engineering》2004,24(12):1003-1011

Based on Biot's wave equation, dynamic response of a circular tunnel with partially sealed liner in viscoelastic saturated soil is investigated. By introducing two scalar potential functions, the analytical solutions of stresses, displacements and pore pressure induced by axisymmetric gradually applied step load are derived in Laplace transform domain. Numerical results are obtained by inverting Laplace transform presented by Durbin and used to analyze the influences of partial permeable property of boundary and viscoelastic damping coefficient of soil on dynamic response of the tunnel. It is shown that the attenuation of radial displacement appeared with the increase of viscoelastic damping coefficient of soil, and relative rigidity of liner and soil, and the influence of partial sealing property of boundary on stresses, displacements and pore pressure is remarkable. The available solutions of permeable and impermeable boundary conditions are only two extreme cases of this paper.  相似文献   

区域地球化学数据的归一化处理及应用   总被引：11，自引：0，他引：11  

刘大文 《物探与化探》2004,28(3):273-275,279

介绍了一种简单的勘查地球化学数据调整方法———归一化,该方法采用各批或各区块差异数据的平均值或中位数的衬值乘以参照值以获得元素的视含量,用于调整不同分析批次之间的系统误差,或不同背景区数据的差异;用2个实例详细介绍了该方法的应用效果。  相似文献   

钱家店铀矿床U-Ra平衡系数特征研究   总被引：1，自引：0，他引：1  

张明瑜  夏毓亮  刘汉彬  田时丰  张泽贵 《铀矿地质》2004,20(6):364-369,329

本文探讨了可地浸砂岩型铀矿U-Ra平衡系数的计算方法，研究了钱家店砂岩型铀矿床U-Ra平衡系数的变化特征。这些成果为钱家店铀矿床放射性测井数据的修正、矿体边界的确定、铀矿资源量的计算提供了科学依据。  相似文献   

煤层气在煤储层中的扩散及其影响因素   总被引：4，自引：0，他引：4  

曹成润  牛伟  张遂安  霍永忠  陈秀艳  孙英男 《世界地质》2004,23(3):266-269

煤层气在煤储层中的扩散是指从煤基质孔隙表面上解吸的煤层气运移到割理系统的主要过程。发生扩散的前提条件是气体浓度差的出现，衡量扩散能力大小的重要参数是扩散系数。前者为由解吸速度、解吸气量和煤层气产量、井孔压力降等因素控制的动态参数，而后者为主要受扩散物质性质、扩散介质特征、扩散系统的温度、压力和孔隙结构形态等因素影响的静态参数。煤层气在煤储层中的扩散量与煤层气浓度差和扩散系数呈正比关系。  相似文献   

某滑坡软弱夹层抗剪强度取值方法的研究   总被引：3，自引：0，他引：3  

王义军  李天斌  王宝国 《中国地质灾害与防治学报》2004,15(4):25-29

文章主要针对软弱夹层抗剪强度取值所存在的争议，通过对贵州新街子滑坡的软弱夹层分别选择比例极限、屈服极限及峰值作为剪应力值，采用最小二乘法获得比例抗剪强度、屈服抗剪强度和峰值抗剪强度。以参数选取中应用较为成熟的反分析方法推求力学性质参数c、φ值作为判据对以上3种参数进行比较。计算结果表明：本滑坡软弱夹层中由于含泥量较大，而且粘塑性较强，屈服抗剪强度和反分析得到的抗剪强度偏差最小，比例抗剪强度偏差最大，峰值抗剪强度居中。并以此3种抗剪强度进行天然状态下滑坡稳定性验算，结果表明选用比例极限抗剪强度与当前滑坡的地质现象不符，选用峰值极限抗剪强度安全储备较低，而选取屈服极限抗剪强度最为合理。用此参数进行设计，滑坡已经得到了良好的治理。在取值研究中认为采用试验与反分析相结合的方法确定滑坡稳定性计算参数是比较合理的。以上结论为滑坡中软弱夹层抗剪强度取值的选择提供了重要的依据。  相似文献   

水布垭面板堆石坝的三维弹塑性数值分析研究   总被引：2，自引：0，他引：2  

汪明元  程展林  林绍忠  陈琴 《岩土力学》2004,25(Z2):507-512

在建的清江水布垭面板堆石坝高达233 m,是目前同类坝型中最高的.采用MSC.Marc非线性有限元程序,发展了三维子模型法,对该坝进行了三维弹塑性有限元仿真分析,模拟了面板的分缝、坝体材料分区、填筑及蓄水过程,采用双屈服面弹塑性模型模拟堆石体的变形特征.根据数值分析的结果,对坝体和面板的应力变形分布规律进行了探讨.  相似文献