Smooth constraint inversion technique in genetic algorithms and its application to surface wave study in the Tibetan Plateau     

吴建平  明跃红  曾融生 《地震学报(英文版)》2001,14(1):49-57

IntroductionThe dispersion phenomena, which can be observed when surface wave travels through the Earth interior, has been extensively applied in investigating the velocity structure of the Earth interior. Usually, the dispersion curve is a nonlinear function of the thickness, S and P wave velocities and density of each layer. Because surface wave inversion is a multiple-minima problem, the result strongly depends on the initial model in traditional linear inversion. Genetic algorithm (GA) …  相似文献   

峨嵋山地区块体图的计算机绘制     

程学忠 《矿物岩石》2001,21(1):101-104

本文介绍了用计算机辅助设计软件AUTOCAD与三维动画软件3DMAX来绘制峨嵋山地区块体图的方法，以此为例子讲述了将地形图改画面三维图的具体操作步骤，并进一步论述了用计算机绘制块体图的方法有着广泛的应用及其实用价值。  相似文献   

Dissolved Humic Substances Can Directly Affect Freshwater Organisms     

Stephan Pflugmacher  Linda Fay Tidwell  Christian E. W. Steinberg 《洁净——土壤、空气、水》2001,29(1):34-40

Direct effects of pure humic substance (BS1 FA) on three different aquatic organisms (Ceratophyllum demersum, Dreissena polymorpha, and Chaetogammarus ischnus) were demonstrated in this study. Exposure to environmentally relevant concentrations (0.5 mg/L) of this humic substance led to the activation of the microsomal and soluble glutathione S‐transferase (GST) in Ceratophyllum demersum. Exposure to 3‐chlorobiphenyl showed also an elevation of GST activity, which is due to the proposed detoxication metabolism of these chlorinated biphenyl. Coexposure to a mixture of 3‐chlorobiphenyl and BS1 FA showed a reduction of enzyme elevation, but still significant over an untreated control. The direct impact of humic substances seems not to be restricted to a specific class of organisms.  相似文献   

Seasonal Forecasting for Climate Hazards: Prospects and Responses     

Murphy  Sarah J.  Washington  Richard  Downing  Thomas E.  Martin  Randall V.  Ziervogel  Gina  Preston  Anthony  Todd  Martin  Butterfield  Ruth  Briden  Jim 《Natural Hazards》2001,23(2-3):171-196

One of the most promising developments for early warning of climate hazards is seasonal climate forecasting. Already forecasts are operational in many parts of the tropics and sub-tropics, particularly for droughts and floods associated with ENSO events. Prospects for further development of seasonal forecasting for a range of climatichazards are reviewed, illustrated with case studies in Africa, Australia, the U.S.A. and Europe. A critical evaluation of the utility of seasonal forecasts centres on vulnerability, communicationchannels, and effective responses. In contrast to short-term prediction, seasonal forecasts raise new issues of preparedness and the use of information.  相似文献   

离子色谱法测定水样中S~(2-)、SO_3~(2-)、SO_4~(2-)、S_2O_3~(2-)     

时艳  刘江潮 《吉林地质》2001,(2)

该种方法利用离子色谱仪的电导检测器与电化学检测器串联 ,十几分钟即可连续完成水中S2 - 、SO2 - 3 、SO2 - 4、S2 O2 - 3 的测定 ,方法具有快速、高效、方便、灵敏、选择性好等特点。方法的检出限分别为 :S2 - 12 5 μg/L ;SO2 - 3 2 2 4 μg/L ;SO2 - 45 0 μg/L ;S2 O2 - 35 0 μg/L。相对标准偏差在 1 5 %～ 6 9%之间 ,能够满足水中S2 - 、SO2 - 3 、SO2 - 4、S2 O2 - 3四种阴离子分析测试的需要。  相似文献   

钾膨胀石墨层间化合物(K-EGIC_S)的电阻率测量     

孔洪亮  陈代璋  曾荣树 《岩石矿物学杂志》2001,20(2):167-170

在低温惰性条件下合成的钾膨胀石墨层间化合物 (K_EGICS)的电学性能与膨胀石墨的电学性能完全相反 ,随着温度的升高 ,K_EGICS 的电阻率逐渐升高 ,电导率逐渐降低。这一现象是由客体材料钾自身的结构及其与膨胀石墨化合时的键性决定的。  相似文献   

对“3S”集成技术的一些认识   总被引：3，自引：0，他引：3  

刘文熙 《四川测绘》1996,19(3):99-103

本文从遥感，地理信息系统和全球定位系统的产生与发展过程，论述了它们走向集成化的必然趋势，说明了“３Ｓ”信息集成技术的涵意；介绍了它的应用领域，最后提出了作者对发展我国以“３Ｓ”集成技术为支撑的地理信息产业应采取的对策的建议。  相似文献   

肃南5.7级地震过程剪切波分裂特征   总被引：3，自引：0，他引：3  

李清河  刘希强 《地震》1996,16(4):417-426

剪切波分裂应用于地震预报中的３个主要困难是：（１）如何自动定量识别剪切波快慢波到时；（２）用以认识其基本特征的震例太少；（３）因各次地震的复杂性，对所给剪切波分裂结果难以给出恰当的解释，本文研究了１９８８年１１月２２日甘肃肃南５．７级地震过程剪切波分裂的特征。所用资料为１９８８年８月到１９９０年８月中法合作张掖数字台网的记录。通过对张掖～肃南地区地壳结构模型的研究，确认了所用各次地震的真实出射角基  相似文献   

Elastic Wave Propagation In A Medium Containing Oriented Inclusions With A Changing Aspect Ratio: A Physical Model Study     

J. M. Ass'ad  J. A. Mcdonald  R. H. Tatham  T. M. Kusky 《Geophysical Journal International》1996,125(1):163-172

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多项地震前兆观测数据的综合参数     

赵卫明  李根起 《内陆地震》1992,6(1):19-24

根据中强地震前前兆观测资料的异常特征和各种前兆异常可信度的差异,考虑到单项观测数据和多项观测数据的相互联系,提出了用综合参数S描述多项前兆观测数据整体变化。结果表明,与单项前兆观测数据比较,综合参数S有变化平稳、震前异常反应明显等优点,可以作为地震预报实践中识别前兆异常的方法之一。  相似文献