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排序方式: 共有3214条查询结果,搜索用时 15 毫秒
61.
上海市长江口及邻近海域地质调查现状及展望 总被引:1,自引:1,他引:0
海洋区域地质调查近年来逐渐得到重视,海洋地质调查技术的发展也为开展海洋区域地质调查奠定了基础。上海地区社会经济发展对地质工作的需求,为摸清上海市长江口及邻近海域的地质现状提出了必然要求。本文在系统整理长江口及邻近海域地质资料的基础上,重点分析了区内存在的重点地质问题和研究存在的问题,根据海洋地质调查的技术发展,结合国内相关地区的调查经验,对长江口及邻近海域内区域地质调查进行了展望,提出了采用综合物探技术、地质取样和测试分析进行综合地质环境调查的建议,并对具体采用的调查技术和调查内容进行了论述。 相似文献
62.
Santschi Peter H. Honeyman Bruce D. Quigley Matthew S. 《Aquatic Sciences - Research Across Boundaries》1993,55(4):230-239
In 1975 Paul Schindler produced the first oceanic trace metal scavenging model to explicitly include the role of surface chemistry as a control on trace metal water column residence times. The eighteen years that have elapsed since the publication of Schindler's seminal paper have seen the development of a variety of oceanic scavenging models; yet, the fundamental insight of his Zero-order Model remains the benchmark. This paper describes the role of Paul Schindler's work on surface chemistry in providing a framework for the current generation of trace element scavenging models. 相似文献
63.
本文通过环境背景值、风化壳地球化学、对流层(大气气溶胶)地球化学和人为地球化学异常,初步探讨了南极长城站地区的现代环境地球化学特征。分析表明:环境要素固有的地球化学性质、区域环境条件和自然环境演变之间具有深刻的内在联系。 相似文献
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65.
Yoshio Takahashi Yutaka Kanai Hikari Kamioka Atsuyuki Ohta Takuro Miyoshi Hiroshi Shimizu 《中国地球化学学报》2006,25(B08):222-222
Sulfates are a main constituent of aerosols, which sulfate aerosols, it is necessary to determine what can cause various environmental problems sulfate ions are contained in these aerosols In the evaluation of the influence of In this study, sulfur K-edge XANES was used to determine sulfate species present in size-fractionated aerosol particles based on the post-edge structure after the main absorption peak in the XANES region. Aerosol samples were collected as part of the Japan-China joint project, "Asian Dust Experiment on Climate Impact" using a low-volume Andersen-type air sampler. XANES was measured at Beamline BL-9A at Photon Factory, Japan. A comparison of the XANES spectra of reference sulfate materials and aerosol samples collected in Tsukuba in Japan clearly showed that (NH4)2SO4 was the main sulfur species in particles with a smaller diameter and gypsum was the main sulfur species in particles with a larger diameter. A simulation of the XANES spectra by reference materials allows us to obtain the quantitative mixing ratios of the different sulfate species present in the aerosol samples. The presence of minor sulfur species other than (NH4)2SO4 and gypsum at the surface of mineral aerosols is suggested in our simulations and by a surface-sensitive conversion electron/He-ion yield XANES. In the absence of a contribution from a large dust event, the mole concentration of gypsum in the mineral aerosol fraction determined by XANES is similar to that of Ca which is determined independently using ion chromatography. This shows that the Ca and sulfate in the mineral aerosols are present only as gypsum. Considering that calcite is the main Ca mineral in the original material arising from an arid and semi-arid area in China, it is strongly suggested that gypsum is formed in aerosol during its long-range transportation by a reaction between calcite and sulfate ions. 相似文献
66.
中国北方地区春季气溶胶光学特性地基遥感研究 总被引:12,自引:1,他引:12
基于中国北方地区地基太阳直接/散射辐射计观测,分析了2001年春季气溶胶光学厚度、尺度和吸收特性。沙尘期间,气溶胶光学厚度显著升高,而尺度上升,粗粒子浓度显著增加,大气气溶胶表现出中性或异常消光特征。除沙尘活动之外,中国华北地区人为排放也是导致气溶胶光学厚度偏高的一个重要原因。中国沙尘源区气溶胶单次散射反照率小于以往观测和模式结果。北京和香河两地气溶胶光学厚度、Angstrom指数和尺度谱基本相似,说明华北地区人为排放与沙尘活动类似,也表现出区域尺度的特点。由于沙尘气溶胶与人为排放气溶胶相比,折射指数实部偏大、虚部偏小,从而北京地区沙尘期间单次散射反照率明显大于非沙尘期间,特别是在近红外波段,说明沙尘活动不仅可以通过增加气溶胶光学厚度,同时也通过改变气溶胶物理、辐射特性来影响下游地区的气溶胶辐射强迫。 相似文献
67.
P. Cereceda P. Osses H. Larrain M. Farías M. Lagos R. Pinto R. S. Schemenauer 《Atmospheric Research》2002,64(1-4)
A project in northern Chile was undertaken to determine the origin and behaviour of fog in the coastal and inland locations of the Tarapacá Region. In the Pampa del Tamarugal, 50 km from the sea, conditions exist for the formation of radiation fog. Advective fog has been studied on the coast and orographic fog was observed at a few coastal sites near mountain ranges with elevations above 1000 m. Fog water collected by two standard fog collectors (SFC) for 3 1/2 years showed an average flux of 8.5 l m−2 day−1 on the coast and 1.1 l m−2 day−1 inland 12 km from the coastline. On only a few days in 10 months was water collected at the inland site of Pampa del Tamarugal. GOES satellite images are shown to illustrate the pattern of formation of the stratocumuli cloud over the sea, its approach to the coastline, the entrance of fog by corridors through the coastal range and the presence of radiation fog inland. The results are important for the understanding of fog formation and dissipation along the coastal mountain range and for the recognition of potential sites for the installation of fog water collectors, which can be used as a water source in the Atacama Desert. The results also provide vital information for use in the preservation of the unique ecosystems of the most arid desert of the world. 相似文献
68.
银川市初夏气溶胶粒子谱分布特征 总被引:4,自引:5,他引:4
利用美制APS—3310A型激光粒谱仪,在中国西北城市银川对大气气溶胶粒子进行现场观测,结合气象条件,并通过理论计算分析,给出了银川市初夏大气气溶胶的日变化特征、3种不同粒径粒子分布特点及飘尘谱分布特征,以期为银川市大气污染总量控制方案及对策提供科学依据。 相似文献
69.
1IntroductionWiththerapiddevelopmentofhumansociety ,industrializationhasbeenspeededup .Asaresult,metalminingandmetallurgy ,coalandgasolinecombustionandchemicalsproductionhavegivenoffalotofPb containingindustrialpollutantswhichhavedonegreatharmtotheecolog… 相似文献
70.