Biogeochemical aromatic markers in the sediments from mahakam delta (Indonesia)     

P. Garrigues  A. Saptorahardjo  C. Gonzalez  P. Wehrung  P. Albrecht  A. Saliot  M. Ewald 《Organic Geochemistry》1986,10(4-6)

Analysis of the tri-, tetraand pentaaromatic hydrocarbon fractions of several sediments (0–600 m) from the Mahakam Delta (Indonesia), indicate the predominance of polycyclic aromatic hydrocarbons (PAH) diagenetically related to triterpenoid natural precursors. High resolution Shpol'skii spectrofluorometry (HRS) proved to be a valuable analytical tool, in conjunction with high performance liquid chromatography (HPLC) and capillary gas chromatography coupled with mass spectrometry (CGC/MS), for the identification of individual components in Chromatographic fractions obtained after a high resolution reverse phase liquid chromatography.  相似文献   

太湖全新世沉积物的古盐度指标及其环境意义   总被引：5，自引：0，他引：5  

王子玉  程安进 《地层学杂志》1994,18(3):196-202

沉积物中的Ｃａ／（Ｆｅ＋Ｃａ）比值和硼含量随水体含盐度的高低而相应增减，它们都是较好的古盐度指标。本文对太湖全新世的沉积物进行了古盐度指标的分析。并与现代湖泊和海洋沉积物作了对比，结果反映东太湖为陆相沉积环境，而西太湖则主要为海相沉积环境。此结论与古生物化石的结论一致，从而证明了太湖地区于全新世期间经历了大规模的海侵，并形成海湾－湖环境。同时也证明了这些古盐度指标是行之有效的。  相似文献   

海气耦合模式的优化方法研究          下载免费PDF全文

魏敏罗勇王兰宁董敏李清泉徐影 《应用气象学报》2005,16(3):408-412

气候模式不断发展的同时，对高性能计算机提出了更高的要求，如何提高模式在现有计算机资源上的运行效率问题已越来越重要。文章介绍了利用编译器优化和手工优化技术对海气耦合模式进行优化试验，优化后模式运行效率提高60%，表明将这些优化方法应用到气候模式的改进工作中，可以达到较好的效果。  相似文献   

季节内振荡研究中两种数字滤波器的性能对比   总被引：7，自引：2，他引：7  

姚菊香  王盘兴  李丽平 《南京气象学院学报》2005,28(2):248-253

就长序列资料的MJO滤波，分析了Lanczos滤波器与Butterworth滤波器的滤波性能，结果表明：1)在滤波器参数n足够大时，Lanczos滤波器对MJO信息的滤出和对非MJO信息盼抑制均优于Butterworth滤波器；2)在分辨率为△=1d、MJO为30～60d定义下，Lanczos滤波器参数的阈值n1=69d，当n≥n1时，可以保证Lanczos滤波器优越性成立。  相似文献   

海温对辽宁省主汛期降水异常影响的统计分析   总被引：1，自引：0，他引：1  

杨文艳  王谦谦 《南京气象学院学报》2005,28(3):404-409

在对辽宁省主汛期降水异常的时变特征进行分析的基础上，研究了前期海温场对辽宁主汛期(7—8月)降水影响的统计特征。结果表明：1)辽宁省汛期降水异常有明显的年际、年代际变化特征，近44a降水呈减少趋势。小波分析表明存在3～5a的年际周期和10～12a的年代际周期。2)存在2个影响辽宁汛期降水异常的海温关键区及相应的关键时段，它们分别是南大西洋(1—5月)和西太平洋(3—4月)，综合考虑2个关键区可更好地预示辽宁汛期降水的异常。  相似文献   

REDEFINING ENSO EPISODES BASED ON CHANGED CLIMATE REFERENCES   总被引：1，自引：1，他引：1  

李晓燕  翟盘茂  任福民  蒋国华 《热带气象学报(英文版)》2005,11(1):97-103

1 INTRODUCTION Since the 21st century, a number of countries and regions, such as the United States[1], Japan[2] and the European Center for Medium Range Weather Forecasts have updated the climatic references in their operational meteorological products from the previous 1961 – 1990 reference period annual mean to the present 1971 – 2000 one. China, beginning from January 2003, also adopted the latter climate reference period. With the use of the new standard, the monthly mean field …  相似文献   

Seismic behavior of asymmetric RC wall buildings: principles and new deformation‐based design method     

Alois Sommer  Hugo Bachmann 《地震工程与结构动力学》2005,34(2):101-124

The seismic design of multi‐story buildings asymmetric in plan yet regular in elevation and stiffened with ductile RC structural walls is addressed. A realistic modeling of the non‐linear ductile behavior of the RC walls is considered in combination with the characteristics of the dynamic torsional response of asymmetric buildings. Design criteria such as the determination of the system ductility, taking into account the location and ductility demand of the RC walls, the story‐drift demand at the softer (most displaced) edge of the building under the design earthquake, the allowable ductility (ultimate limit state) and the allowable story‐drift (performance goals) are discussed. The definition of an eccentricity of the earthquake‐equivalent lateral force is proposed and used to determine the effective displacement profile of the building yet not the strength distribution under the design earthquake. Furthermore, an appropriate procedure is proposed to calculate the fundamental frequency and the earthquake‐equivalent lateral force. A new deformation‐based seismic design method taking into account the characteristics of the dynamic torsional response, the ductility of the RC walls, the system ductility and the story‐drift at the softer (most displaced) edge of the building is presented and illustrated with an example of seismic design of a multi‐story asymmetric RC wall building. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Eco-hydrology: Groundwater flow and site factors in plant ecology   总被引：7，自引：0，他引：7  

Frans Klijn  Jan-Philip M. Witte 《Hydrogeology Journal》1999,7(1):65-77

 In plant ecology, site is a central concept. A site is the place where a plant species or plant community grows, and the site provides the set of conditions in which it lives. Within an initially homogeneous parent material, gravity-driven groundwater flow influences the site conditions through the spatial distribution of nutrients and other relevant chemical agents. Especially upward seepage may produce and maintain site conditions that are essential for various relatively rare plant species and communities. Increased attention to upward seepage among ecologists has resulted in cooperation with hydrologists and the emergence of a discipline of its own – eco-hydrology – on the boundary of two scientific fields, linked by the site concept. In the Netherlands, a simple classification of water types, based on the groundwater's subsurface history, was applied for compiling a nationwide geographical database on ecologically relevant upward seepage. Correspondence analyses of this database with data on plant-species occurrence demonstrate that in poor Pleistocene sandy soils upward seepage explains the occurrence of some species and communities quite well, whereas in fluvial plains and polder areas with richer clay soils the influence of seepage is blurred by the importance of soil characteristics. It is concluded, therefore, that plant species may be used as seepage indicators in rapid assessments and surveys, but that constant awareness of the limitations is required. Received, July 1998 · Revised, September 1998 · Accepted, October 1998  相似文献   

A NEW PERSPECTIVE ON CHINA'S INDUSTRIAL DEVELOPMENT STRATEGY     

陈国阶 《中国地理科学(英文版)》1999,(4)

１　ＩＮＴＲＯＤＵＣＴＩＯＮＮｏｗａｄａｙｓｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｗｏｒｌｄｉｎｄｕｓｔｒｉｅｓａｎｄｅｃｏｎｏｍｙｉｓｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆａｆｅｗｃｏｎｓｐｉｃｕｏｕｓｔｒｅｎｄｓｗｈｉｃｈｍａｙｃｈａｌｌｅｎｇｅｔｒａｄｉｔｉｏｎａｌｅｃｏｎｏｍｉｃｄｅｖｅｌｏｐｍｅｎｔｍｏｄｅｌｓａｎｄｔｈｅｏｒｉｅｓ．Ｆｉｒｓｔｏｆａｌｌ,ｔｈｅｅｃｏｎｏｍｙｏｆｔｈｅｗｏｒｌｄｈａｓｂｅｅｎｂｅｃｏｍｉｎｇｉｎｇｌｏｂａｌｓｐａｃｅ,ｏｆｗｈｉｃｈｔｈｅｒｅｍａｒｋａｂｌｅｉ…  相似文献   

浅谈地勘单位的市场观念     

刘仕梅 《南方国土资源》1999,12(4):61-62

在分析地勘单位当前面临的困难及其原因的基础上 ,认为地勘单位应充分发挥自身人才优势和技术优势 ,特别是建立稳定的骨干产业 ,才能牢固确立在社会主义市场经济中的地位。  相似文献