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11.
Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability
of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing
at deeper depths in the intermediate layer took place in the late 1960’s and the mid-1980’s. Records of winter sea surface
temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods.
Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold
winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960’s and the
Central Water in the mid-1980’s. 相似文献
12.
以淮南刘庄煤矿主井地基的人工冻融土为研究对象,以偏光显微镜,扫描电镜(SEM)为主要研究手段,研究分析了人工冻融土与原状土的中微观结构、冻融前后的中微观结构的变化规律及内在原因。此外,还研究分析了人工冻融土冻融前后的中微观结构及其变化与人工冻融土的物理、力学、工程性质之间的关系。研究显示中微观结构对人工冻融土的物理、力学、工程性质有很大的影响,冻融前后中微观结构的变化受到土的种类、埋深、原状土的中微观结构等因素的影响,且冻融前后的中微观结构的变化在一定程度上主导了冻融前后的物理、力学、工程性质的改变。 相似文献
13.
闫晓光 《测绘与空间地理信息》2008,31(2):67-70
阐述了基于GIS房产管理的关键是建立统一的数据分类与编码标准,核心是建立房屋的空间地理属性信息、自然属性信息、社会人文属性信息的链接,基础是建立房产地理信息数据库。并提出了建立房产地理信息数据库的方法、设计思路和方式。 相似文献
14.
烃气测量是油气化探最主要的方法。目前应用的烃气测量方法有两类:一类是测量土壤中游离烃气如K—V指纹法、吸附丝法、物上气法及直接取土壤气测量法等。此类方法由于需特殊设备及壤气测量方法本身固有的缺陷,目前还未得到普遍应用,另一类为土壤吸附烃气法即国内外目前普遍使用的酸解烃气法、此法在多数油气田上取得好效果,但也有相当多的地区如黄土、荒漠及水网发育等特殊景观区效果不好或不显著。本文介绍一种新的烃气测量法──土壤相态烃测量法。这是用一种特殊的技术,只选择性提取由油气藏渗漏过程中保存在运移通道围岩及近地表土壤各种次生矿物结构中以"穴居"态存在的轻烃组分。"穴居"态烃为累积性的指标,不受外界温度、修水等的影响,保存较牢固,测定结果稳定。相态烃法避免了酸解烃法存在的生物成因烃、矿物同生烃及碳酸盐的干扰影响,提高了测量指标的信噪比,突出了应有的异常。本方法已在黄土厚覆盖区两个已知油气田和一个风成沙覆盖的断裂发育油田上试验获得成功,结果表明相态烃法优于酸解烃法。 相似文献
15.
我国藻菌生物成因的金矿研究 总被引:1,自引:0,他引:1
生物成矿作用分为生物直接成矿作用和生物间接成矿作用,生物直接成矿作用的标志结构为生物有机胶体结构。生物间接成矿作用的标志结构为“矿交代生物”结构,我国陕西二台子-半仓沟金矿,四川东北寨金矿、川甘拉尔玛金矿和云南金厂金矿等均为典型为实例,矿石中普遍含有多种金属矿物生物结构,还含多种生物有机组分。成矿物质具有多源性特征,硫同位素具混合型特征,矿床成型机制可与“人工碳吸附系统”聚金机制相类比,含金层位可 相似文献
16.
Micro-spectroscopic investigations of highly heterogeneous waste repository materials 总被引:1,自引:0,他引:1
A.M. Scheidegger D. Grolimund C.R. Cheeseman R.D. Rogers 《Journal of Geochemical Exploration》2006,88(1-3):59
Assuring safe disposal and long-term storage of radioactive and toxic wastes corresponds to a primary environmental task of present societies. To improve any technical limitation, a mechanistic understanding of the processes governing the binding of heavy metals and radionuclides is required. In this study, the significance of synchrotron-based X-ray microprobes for elucidating the spatial distribution and the speciation of radionuclides in highly heterogeneous waste repository materials will be outlined. A case study on the uptake process of Co in cementitious engineered barrier materials exposed to microbial degradation will be presented. 相似文献
17.
Jin-Soo Lee Kyung-Seok Ko Tong-Kwon Kim Jae Gon Kim Seong-Hyun Cho In-Suk Oh 《中国地球化学学报》2006,25(B08):152-152
The regional survey of groundwater used as a small water supply system was performed to know the effect of geology, soil properties and land use on groundwater quality at Nonsan City, Korea. A total of 126 groundwater samples were collected and analyzed at the study area. The multivariate statistical methods, principal components analysis and discriminant analysis, and GIS technique were used for the quantitative interpretation of groundwater quality. The study area is mainly composed of Precambrian gneiss, Jurassic granite, and Cretaceous volcanics, and metasedimentary rocks of the Ogcheon zone. The land use was grouped as paddy, upland, grassland, resident, point source, industrial area, and water system. The soil properties were classified as 4 major groups, Entisols, Alfisols, Inceptisols, and Ultisols, by the degree of development, and reclassified as 11 subgroups. The modified and simplified geologic map, soil map, and land use map were made by using ARCGIS soft-ware. The area of geology, soil property, and land use affecting the groundwater quality for each well were also calculated by ARCGIS soft-ware to acquire the quantitative parameters for multivariate statistical analysis. The monitoring results of groundwater in the study area showed that 13%-21% of the groundwater samples exceeded the portable water guideline and the main causes were turbidity, bacteria, arsenic and nitrate-N. The spatial distribution of each component showed the close relationship between groundwater quality and geology reflecting the topography, land use. 相似文献
18.
WANG Lei ZHANG Guang-Xin 《湿地科学》2006,4(3):193-197
1 INTRODUCTIONNitrogen and phosphorus in the water are the nu-trients limited in natural wetlands,which seriously in-fluence on the ecosystem production and the biodiver-sity(Mitsch,Grosselin,2000).Nitrogen and phos-phorus recycles have been interrupted b… 相似文献
19.
John A. Gillies William G. Nickling Vicken Etyemezian James King Mark Sweeney 《中国地球化学学报》2006,25(B08):219-220
New field measurement techniques are allowing researchers to better understand how surficial properties affect the temporal and spatial variability of dust emissions. In this paper we review the current understanding of the dust emission process and present new field measurements that examine how three surface properties: roughness, crust strength, and temporal changes of surface properties affect dust emissions. These data were collected using three unique measurement systems developed by our team. Roughness exerts considerable control on the entrainment threshold and emissions of dust from a surface. We have carried out a series of experiments designed to quantify roughness effects on aeolian sediment entrainment and transport in a shear stress partitioning framework. Our results show that the model of Raupach et al. (1993) provides very good agreement with available data to predict the amount of shearing stress on the intervening surface among roughness elements, relatively independent of their size and distribution. However, element size affects the aeolian sediment transport process beyond that attributable only to the reduction of surface shear stress caused by the roughness. Additional interactions of the elements with the saltation cloud appear to reduce the transport efficiency and potentially dust emissions as well. The effect of crust strength on dust emissions was assessed using a newly-developed pin penetrometer, which can measure crust strength in-situ. Previous researchers suggested that variation in crust strength even within a small area could lead to considerable spatial variability in dust emissions. Our measurements showed that crust strength is highly variable over a scale of centimeters. This variability may help to explain some of the observed scatter in field measurements of dust emissions for what appear to be homogeneous surfaces. Variability of dust emissions in time and space was also evaluated using a new instrument, the Portable In-Situ Wind Erosion Lab (PI-SWERL) developed to measure dust emissions from soil surfaces. 相似文献
20.
采用密闭室红外气体分析仪法(IRGA法)观测了中亚热带红壤侵蚀裸地植被恢复后不同季节土壤呼吸速率的日动态变化,并比较了IRGA法与碱吸收法(AA法)测定的土壤呼吸速率.结果表明:侵蚀裸地植被恢复后土壤呼吸速率日动态呈单峰曲线,与土壤温度的昼夜变化基本一致,最高值一般出现在午后13∶00~17∶00,最低值出现在凌晨3∶00~7∶00;植被恢复显著提高了土壤日呼吸速率,但明显降低了土壤呼吸速率日变化幅度;马尾松林对土壤呼吸速率日变化幅度降低程度高于板栗园和百喜草地,且对夏季的降低程度影响最大.而IRGA法和AA法测定的土壤呼吸速率具有显著的幂函数关系,AA法测定的土壤呼吸速率为IRGA法的27.5%~218%,平均为76.2%.当土壤呼吸速率较低时,AA法比IRGA法高估了土壤呼吸速率;反之,AA法则低估了土壤呼吸速率. 相似文献