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   

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   

主成分分析法在神经网络集成预报中的应用   总被引：2，自引：0，他引：2       下载免费PDF全文

盛飞 《气象科学》2005,25(4):362-368

本文将主成分分析方法引入到用神经网络作集成预报中，根据各个主成分的方差贡献的大小来确定所需主成分的个数，在此基础上，对集成预报的原始因子进行重构，以达到对数据进行降维，加快计算速度和提高预报准确率的目的。  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   

Consolidation and Break-up of the South American Platform in Southeastern Brazil: Tectonothermal and Denudation Histories   总被引：1，自引：0，他引：1  

P.C. Hackspacher  L.F.B. Ribeiro  M.C.S. Ribeiro  A.H. Fetter  J.C. Hadler Neto  C.E.S. Tello  E.L. Dantas 《Gondwana Research》2004,7(1):91-101

The different tectonic stages that occurred at the end of the Proterozoic and during the Phanerozoic have an important bearing on the tectonothermal history of the South American Platform and its consolidation. Geochronological data (U/Pb monazite, ⁴⁰Ar/³⁹Ar whole rock) and apatite fission-track analysis, from Precambrian rocks of the southeastern Brazilian coastline, permit the modeling of a long-term thermal history of the crust and constrain variable denudation rates.Using these data, a temperature-time diagram reflects a period of accelerated exhumation during the end of the Brasiliano Orogeny, followed by long stability and reactivation of the platform during the Rifting Phase of the South Atlantic Ocean.U/Pb zircon and monazite (blocking temperature of ca. 650° C) data from a series of igneous bodies suggest that a tangential and transpressional tectonic regime occurred between 625 and 610 Ma. During the following escape tectonics, between 610 and 590 Ma the exhumation process indicates cooling rates of ca. 12°C/Ma. ⁴⁰Ar/³⁹Ar biotite ages between 540 and 510 Ma (ca. 300°C) and a corrected fission-track age on apatites (100°C) of 480 Ma indicate an exhumation event related to block tectonics with huge vertical displacement along shear zones.A long stabilization phase, with low exhumation, and cooling rate around 0.25°C/Ma was recorded from the Cambro/Ordovician to the Mesozoic. At 65 Ma an acceleration of the exhumation through denudation and reworking of the South American surface with cooling rate of 1.5°C/Ma is observed.The uplift of the Mantiqueira and Serra do Mar mountain ranges along the southeast Brazilian coastline works as a climatic barrier provoking lateral erosional processes causing long-term scarp retreat, combined with intense, but progressive denudation towards the continent. A denudation of 2.5 to 4 km was calculated for such processes. This lateral retreat of escarpments and flexural response can provide important insights regarding marginal isostatic uplift and the evolution of offshore sedimentary basins of southeast Brazil.  相似文献   

Optimisation of the Operation of an Electrochemical Process To Treat TBT‐contaminated Sediments on a Pilot Scale     

Eduardo Arevalo  Arne Keller  Heinz Stichnothe  Wolfgang Calmano 《洁净——土壤、空气、水》2004,32(6):401-410

Since at least three decades tributyltin had been commonly used in paint formulations to protect ship hulls and submersed surfaces from fouling. This has resulted in negative and Technology, effects to the marine environment due to its high toxicity towards non‐target organisms and to its accumulation in sediments, especially near point sources of pollution. Even if a ban of TBT for its application in anti‐fouling paints is enforced the problem of TBT‐contaminated sediments will remain for the coming years due to the low degradation rates of organotin in sediments. In this work an electrochemical process at a pilot scale to destroy TBT in sediments was investigated. Previous experiences at a laboratory and technical scale have demonstrated the potential of this process to electrolytically degrade organotin species in sediments. This article deals with the optimisation of the pilot plant performance in terms of organotin degradation and operation costs monitoring additionally the effect of the electrochemical treatment on other pollutants such as heavy metals, PCBs, and PAHs. The aim was to investigate by means of a parametric study the range of operating conditions required to destroy TBT down to concentrations lower than 100 μg/kg; to determine the influence of those parameters on the performance of the process; and to evaluate the operation costs associated to the process. It was determined that it was possible to destroy TBT down to 100 μg/kg at current densities in the range of 4.4 to 6.6 mA/cm² and chloride concentrations of least of 0.2 mol/L with operation costs of 13 to 18 EUR/m³.  相似文献   

2002年12月17日玉门M_L4.5地震的强震仪多条记录资料分析          下载免费PDF全文

何少林  闵祥仪  何新社 《地震工程学报》2004,26(3):274-279

对2002年12月17日玉门ML4．5地震近场多道强震仪的加速度记录进行了分析处理，校正了仪器响应和基线，计算了速度和位移时程曲线及各种谱值，并对记录特点做了分析。  相似文献   

喀什地磁台数字与模拟记录K指数对比分析   总被引：1，自引：0，他引：1  

孙海军  高守全 《内陆地震》2007,21(4):348-353

介绍了喀什地磁台地磁数字记录K指数的计算机FM I测定方法和传统的模拟测定K指数方法,分析比较了数字和模拟测定K指数存在的差异和原因。与国家地磁台网2005年统计的平均数据进行了比较,数字记录测定比模拟测定的值更好,数字记录更真实、更准确地反映出地磁场活动状态,因此在实际量算K指数时应以数字测定为准。  相似文献   

库仑法测定煤中全硫必须重视的问题     

雷翠琼 《云南地质》2007,26(4):458-460

煤中全硫测定是煤质分析的一项重要指标。本文从煤样的粒度和均匀性,载气流量,电解液的使用,电解池和电极片的处理,库仑测硫仪的校正等方面对应用库仑法测定煤中全硫应注意的问题及原因进行分析,以确保测定结果的准确性。  相似文献