丘陵山区食物生产变化规律——以江西省为例     

吕爱清  邱爱保  卞新民  杜国平  陈路扬 《山地学报》2006,24(4):459-465

1978-2003年江西食物生产总量与食物生产要素保障度呈高度正相关（0．885），这表明江西食物生产总量受生产要素投入驱动，资源因子锐减是导致2000-2003年江西食物总量下降的主要原因。洪涝灾害面积、低温灾害面积、洪涝绝收面积和低温绝收面积是导致自然灾害的强驱动因子，干旱灾害面积、干旱绝收面积、风雹灾害面积和风雹绝收面积是导致自然灾害的次强驱动因子。灌溉面积、农业劳动力等食物生产要素的波动与同期食物生产波动具有显著关联性，其显著关联序为：灌溉面积波动〉总种植面积波动〉农业劳动力波动〉农业资金投入波动〉化肥用量波动。1978-2003年江西食物波动指数与全要素相对生产率（TFRP）的走势基本一致，表现为食物波动平稳或食物呈较大正波动时TFRP较高，生产要素配置合理；而食物呈较大负波动时TFRP往往偏低。  相似文献   

基于梁格理论的人字形桥梁动力特性分析   总被引：4，自引：0，他引：4       下载免费PDF全文

卢彭真  张俊平  刘爱荣  梅力彪 《地震工程学报》2006,28(1):31-35

基于梁格理论采用通用有限元程序软件SAP2000对典型人字形桥梁结构的振动频率及振型进行了模拟分析,并讨论了主要结构参数对其动力特性的影响,可为人字形桥梁的动力设计提供参考。  相似文献   

广东省及邻区活动断裂的实验研究   总被引：2，自引：0，他引：2  

颜玉定  李亚林  刘特培  欧阳立胜  官幼雄 《华南地震》2006,26(4):14-25

从实验应力分析和岩石力学的角度,综合其它学科的相关理论,给出了一种有别于传统的活动断裂的新定义及其判据。其定义为:在现代构造应力场中,存在沿原断裂面破裂和扩展的断裂。其判据为:①某断裂走向与主压应力1σ方向所夹的锐角0°≤β≤50°时,其为活动断裂;②β=25°的断裂为最活动的断裂。通过对广东省及邻区活动断裂的实验研究还得到其1σ方向分布图(广东省域从东到西,1σ方向大致为305°～360°～15°)、活动断裂或活动断裂分段的走向范围以及主要活动断裂分段内潜在的最大地震。大致为:①NW走向的断裂,除西部极少数外,全部是活动断裂。各断裂分段内潜在的最大地震在MS 5.1～7.4级之间:②研究区东部的近EW向断裂、西部NE向断裂的部分分段和SN向断裂,也是活动断裂。各分段内潜在的最大地震在MS6.8～7.5级之间。  相似文献   

Permanent seismic deformation analysis of a landslide     

Ashok K. Chugh  Timothy D. Stark 《Landslides》2006,3(1):2-12

A failed slope may not necessarily require a remedial treatment if it can be shown with confidence that the maximum movement of the slide mass will be within tolerable limits, i.e., not cause loss of life or property. A permanent displacement analysis of a landslide for static and seismic conditions is presented using a continuum mechanics approach. Computed values of displacement for static conditions compare favorably with field measurements and computed values of seismic displacements for a postulated earthquake motion appear reasonable. Also, the seismic displacements using the continuum mechanics approach compare favorably with those obtained using the Newmark sliding block procedure for assessing seismically-induced slope deformations.  相似文献   

新疆东准噶尔蚀变矿物填图及多元信息找矿   总被引：9，自引：0，他引：9  

周军  陈明勇  高鹏  刘磊  李得成  田勤虎 《国土资源遥感》2005,(4):51-55,i0003

选择Crosta和主成分分析方法对新疆青河、奇台、巴里坤一带进行矿化蚀变信息提取，以μ＋1．64σ～μ＋2σ、p＋2σ～p＋3σ及〉μ＋3σ三级阈值分割遥感异常信息，并按不同色彩叠加于1：20万或1：5万化探数据与遥感数据融合的图像上，经综合分析和部分实地查证，提出青河小萨尔布拉克、科克玉依、喀拉套弧形构造、奇台北塔山牧场场部、乌伦布拉格以及巴里坤大红山及草湖沟等为重要找矿地段。  相似文献   

左江洪涝特征分析   总被引：1，自引：0，他引：1  

张健 《气象研究与应用》2005,26(3):24-26

台风是造成左江洪涝的主要影响系统,后汛期洪涝频率明显高于前汛期,洪水汇流量与降雨性质、地形地貌、土壤含水量有关,依不同降雨量径流量不同的原理及洪涝特征估测洪水量、洪峰流量较接近实况,具有应用价值。  相似文献   

Seismic upgrade of hydraulic fill dam by buttressing   总被引：1，自引：0，他引：1  

L.H. Mejia  J.I. Sun  K.K. Leung 《Soil Dynamics and Earthquake Engineering》2005,25(7-10):571-579

The vulnerability of hydraulic fill dams under strong earthquake shaking has long been recognized. When located in areas of high seismic hazard, seismic upgrading of these types of dams is often required to meet current dam safety standards. Selection of an appropriate design concept for seismic upgrading of such dams requires careful consideration of seismically induced deformations when the hydraulic fill is to remain as part of the dam. This paper presents a case history of the seismic upgrade of Butt Valley Dam, a hydraulic fill dam located in Northern California. The dam was strengthened to withstand the Maximum Credible Earthquake (MCE) by buttressing of its upstream and downstream slopes. The paper discusses the evaluation of alternatives to upgrade the dam, the design criteria, and the design and analysis of the seismic upgrade. It is shown that a conservative and robust design was developed based on well-established engineering principles and multiple lines of defense, and sound use of analysis procedures including finite-difference non-linear dynamic deformation analyses.  相似文献   

Physico-chemical and biological sediment properties determining erosion resistance of contaminated riverine sediments – Temporal and vertical pattern at the Lauffen reservoir/River Neckar, Germany     

Sabine Ulrike Gerbersdorf  Thomas Jancke  Bernhard Westrich 《Limnologica》2005,35(3):132-144

In order to contribute to a reliable, easy-to-handle and economically viable erosion risk assessment of contaminated riverine sites, the present study aims to implement master-variables best characterising the sediment stability. Thus, a wide range of sediment properties was related to the critical shear stress for mass erosion, determined in the SETEG (Stroemungskanal zur Ermittlung der tiefenabhaengigen Erosionsstabilitaet von Gewaessersedimenten) pressurised channel, with special emphasis on vertical and temporal gradients in the Lauffen reservoir on the River Neckar. Over the course of 1 year, positive impacts of some macrofauna species and benthic diatoms on the sediment stability were detected for the sediment surface (0.5 cm). However, a high seasonal variability of biological parameters caused varying relations with erosion resistance in the upper sediment layers as shown for the colloidal carbohydrates. Considering only deeper sediment layers (5–35 cm), a more general pattern could be revealed with correlations between the critical shear stress and single sediment properties such as depth, grain size, total organic carbon (TOC), cation exchange coefficient (CEC), carbohydrates and proteins. Firstly, the influence of physico-chemical and biological properties on erosion resistance became evident, even over depths at 0–35 cm. Secondly, inter-particle forces are most important for erosion resistance. These are enhanced in fine-grained sediment layers, offering high binding capacities but also strengthened by polymeric substances permeating the void space and coating particles. These covariance patterns of sedimentological and biological parameters are addressed by multivariate statistical tests (principal component analysis), resulting in a higher magnitude of the correlation coefficient between critical shear stress and the master-variables in main component II (polymeric substances, grain size, TOC, CEC; R=0.77) compared to single correlations.  相似文献   

会泽铅锌矿矿山厂矿段趋势面分析及深部预测   总被引：1，自引：0，他引：1  

陈仕炎  高建国 《云南地质》2005,24(4):442-449

编写多项式趋势面分析程序，在MAPGIS软件平台上，绘制平面及立体等值线图，展示矿山矿段矿体赋存层位上（下）层面的起伏、赋存层位厚度、矿体厚度、铅锌品位等7个参数空间变化特征和趋势，总结矿体空间分布和变化规律趋势，提出深部成矿预测靶区。  相似文献   

基地交通组织与医院改扩建中人性化设计   总被引：1，自引：0，他引：1  

陆激  方庆 《中国勘察设计》2005,(8):15-17

本文认为交通组织是医院改扩建中人性化设计的重点之一,提出了一系列的分析研究步骤,并以实例加以说明.  相似文献