全谱直读等离子发射光谱法直接测定天然矿泉水中的SO2-4   总被引：2，自引：0，他引：2  

查立新  刘洪青  马玲  戴先蓉 《安徽地质》2002,12(1):75-77

采用全谱直读等离子发射光谱(ICP-AES)直接测定天然矿泉水中SO2-4的方法在优化工作条件下SO42-的测定下限为0.09mgL-1,方法简便,快速,适用于批量生产.  相似文献   

Where the buffalo roam: Boundaries and the politics of scale in the yellowstone region     

Jean Lavigne 《GeoJournal》2002,58(4):285-292

For more than twenty years, the state of Montana has pursued a controversial policy of lethal control to manage winter migrations of bison from Yellowstone National Park. In the late 1990s, as the state and a number of federal agencies attempted to cooperatively outline a more palatable scenario for bison management, local environmental groups became active participants in the debate. This paper examines the strategies pursued by these organizations in the course of their attempt to construct a new, ecosystem-level territorial space and jurisdictional scale for bison, and places their struggle within the context of existing work in geography on the politics of scale. Ultimately, the failure of their efforts illustrates some of the important constraints faced by social groups that attempt to create new territorial regimes and new scales of resistance in the interstices of existing political structures.  相似文献   

GEOCHEMICAL EFFECTS OF MAJOR ELEMENTS DURING FLUID-ROCKS INTERACTION IN MARINWOBO FAULT IN THE SOUTH MARGIN AREAS OF ALTAI MOUNTAINS     

ZHAO Zhi-zhong ZENG Qiao-song BI Hua 《大地构造与成矿学(英文版)》2002,(2):68-75

There are four types of metamorphic rocks in the Marinwobo fault, i. e, cataclasite, mylonite,mictosite and migmatitic granite, and the formation of these rocks is due to the progressive metamorphism of the pyroclastics. The fluids play a very important role in the metamorphic process of these rocks in the Marinwobo fault, the most important feature is that the fluids not only result in the migration of the major elements of the deformation rocks, but also result in the volume loss of the deformation rocks in the deformation process. Thus the migration laws of the major elements in different stages of the progressive metamorphic process are discussed according to mass balance equations. Finally, the quantitative analysis of the mass loss and volume loss of the different rocks the in Marinwobo fault is discussed in this paper.  相似文献   

EXPERIMENTAL AND FIELD STUDY ON MINING-PIT MIGRATION   总被引：5，自引：0，他引：5  

S.Ali Akbar Salehi NEYSHABOURI  Ali FARHADZADEH  Ata AMINI 《国际泥沙研究》2002,17(4)

1 INTRODUCTION Because of the large quantity of sand and gravel in their beds, rivers have always been considered as a major source of sand and gravel for civil works. Acceptable quality, ease of extraction and economy are some of the reasons could be mentioned. Unfortunately, specific laws and regulations regarding the safe in-stream mining have not been provided for users and officials. What should be taken into account are the effects of over-mining of sand and gravel, which can cause …  相似文献   

基于波动方程的广义屏叠前深度偏移   总被引：15，自引：7，他引：15       下载免费PDF全文

金胜汶  许士勇  吴如山 《地球物理学报》2002,45(5):684-690

地震波传播算子的计算效率和精度是制约三维叠前深度偏移的关键因素. 广义屏传播算子(GSP, Generalized Screen Propagator)是一种在双域中实现的广角单程波传播算子. 这一方法略去了在非均匀体之间发生的交混回响,但它可以正确处理包括聚焦、衍射、折射和干涉在内的各种多次前向散射现象. 通过背景速度下的相移和扰动速度下的陡倾角校正,广义屏算子能够适应地层速度的强烈横向变化. 这种算子可以直接应用于炮集叠前偏移,通过将广义屏算子作用于双平方根方程,还可以获得一种高效率、高精度的炮检距域叠前深度偏移方法,用于二维共炮检距道集和三维共方位角道集的深度域成像. 本文首先简述了炮检距域广义屏传播算子的理论,进而讨论了共照射角成像(CAI, Common Angle Imaging)条件,由此给出各个不同照射角(炮检距射线参数)下的成像结果,进而得到共照射角像集. 由于照射角和炮检距的对应关系,共照射角像集又为偏移速度分析和AVO(振幅随炮检距变化)分析等提供了有力工具.  相似文献   

雄关漫道真如铁——论中国油气二次创业   总被引：17，自引：19，他引：17  

刘光鼎 《地球物理学进展》2002,17(2):185-190

半个多世纪以来，中国经历了油气资源的第一次创业，在祖国大陆和近海大陆架地区的新生代陆相碎屑岩沉积盆地中，发现了一批油气田，使原油年产量达1．67亿吨，位居世界第五，天然气疸这241亿立方米，居世界第十五位，成绩是巨大的，但是，1993年开始进口原油3000万吨，2000年进口原油7200万吨，严重影响国家经济建设，而且这种趋势还在不断发展，预测2010年将进口原油1亿吨，天然气200亿立方米，那么，中国油气资源的出路何在？作者指出，从中国大地构造演化来看，前新生代海相残留盆地还有巨大的油气潜力，尽管其勘探的难度是世界级的，但是，只要我们切实地依靠科学技术，进行油气资源的二次创业，困难上，在实践中克服困难，就可以发现更多的石油天然气，支持国家经济建设的持续发展。  相似文献   

Phototransformation of aromatic pollutants in solar light: Photolysis versus photosensitized reactions under natural water conditions   总被引：3，自引：0，他引：3  

Delphine Vialaton  Claire Richard 《Aquatic Sciences - Research Across Boundaries》2002,64(2):207-215

  相似文献   

我国西部生态退化的社会经济分析--以川西为例   总被引：9，自引：11，他引：9  

陈国阶 《地理科学》2002,22(4):390-396

导致川西生态退化主要原因是经济发展水平低，人口超过环境容量，农村生产方式和生活方式落后，以柴、粪为薪、天然放牧，陡坡垦殖，砍伐森林等导致植被破坏，草场退化，水土流失，据此，对川西的区域资源优势，川西较低密度人口，川西资源开发和支柱产业选择应重新评价和定位。进行川西生态建设，实施可持续发展战略，必须营造开放的社会－经济－自然复合系统的耗散结构，构造社会、经济发展与生态建设协调的有序结构和机制。同时，较彻底地改造农林牧生态系统，开创与生态协调的农业结构，生产模式，种植模式和管理模式，进行农牧区社区建设，根除刀耕火种，陡坡垦殖，游牧的社会基础。  相似文献   

海岸带遥感资源调查的计算机解译方法探讨     

李柏良  许学工  林辉 《地理与地理信息科学》2002,18(2):34-37

该文介绍了一种利用计算机遥感图像解译进行资源调查的方法———斑块边界自动矢量化辅以目视栅格图像校正法。解译的主要步骤包括 :建立解译标志、影像配准、数据分析、图像增强、监督分类、目视解译修正、草图输出、实地检验、栅格转矢量、结果输出等。笔者结合案例对每一步出现的问题及其解决方法进行了探讨 ,并取得了海岸带资源遥感调查蓬莱幅的结果  相似文献   

Geographies of Displacement: The Karenni and The Shan Across The Myanmar-Thailand Border   总被引：1，自引：0，他引：1  

Carl Grundy-Warr  & Elaine Wong Siew Yin 《Singapore journal of tropical geography》2002,23(1):93-122

First, central to our analysis is the argument that human movement within and across borders fundamentally challenges the view of geopolitics based upon fixed territorial states, inter-state relations, national identities and citizenship; indeed the whole idea of "national geographic". Using the examples of the Karen and Shan peoples, we explore the processes and patterns of forced relocation, displacement and migration in the border regions of Myanmar and Thailand. Our main concern is with forced displacement as a result of political and ethnic conflict; specifically, how the Burmese military regime's desire for "national unity" within Myanmar's "national space" has influenced the militarily inspired displacements of hundreds of thousands of villagers and civilians within the border zones inhabited mostly by so-called "national minorities". We examine the particular problems of the so-called "internally displaced persons" within "national" boundaries compared with the "refugees" and "undocumented migrants" who make it across "international" space into Thailand. We illustrate the ways displaced people are represented by state agencies and the media as "threats" and "transgressors". We consider some of the "long term" aspects of the displacement problem along the Myanmar-Thai border and the vital contribution geographers can make to the study of displacement.  相似文献