Hydrogeochemistry of karst underground waters at shallow depth in Guiyang City, Guizhou Province

The aim of this study is to shed light on the hydrogeochemical characteristics of karst underground waters at shallow depth in Guiyang City, Guizhou Province with an emphasis on the geochemistry of major elements. Guiyang City bears abundant underground waters and it is also an important representative of the karst areas throughout the world. Ca^2 and Mg^2 are the dominant cations, accounting for 81% -99.7% of the total, and HCO3^- and SO4^2- are the dominant anions. Weathering of limestones and dolostones is the most important factor controlling the hydrogeochemistry of underground waters, and weathering of sulfate and evaporite rocks is less important. Moreover, the precipitation and human activities also have a definite influence on the hydrogeoehemistry of underground waters in the region studied.     

1961-2004年宁夏极端气温变化趋势分析

 利用1961-2004年宁夏逐日最高、最低气温资料,分析了宁夏44 a来最高、最低气温的变化趋势。结果表明：宁夏的最高、最低气温表现出了明显的变化趋势,最高气温＜0℃的日数减少,＞30℃的日数增加;在年平均最低气温升高的同时,极冷日数也在增加,相对于1961-1990年的平均值,20世纪90年代和21世纪最初的4 a年极冷日数分别增加了1.1 d和0.7 d,距平百分率分别达350%和275%。     

Dynamic analysis of slab track on multi-layered transversely isotropic saturated soils subjected to train loads

The dynamic responses of a slab track on transversely isotropic saturated soils subjected to moving train loads are investigated by a semi-analytical approach. The track model is described as an upper Euler beam to simulate the rails and a lower Euler beam to model the slab. Rail pads between the rails and slab are represented by a continuous layer of springs and dashpots. A series of point loads are formulated to describe the moving train loads. The governing equations of track-ground systems are solved using the double Fourier transform, and the dynamic responses in the time domain are obtained by the inverse Fourier transform. The results show that a train load with high velocity will generate a larger response in transversely isotropic saturated soil than the lower velocity load, and special attention should be paid on the pore pressure in the vicinity of the ground surface. The anisotropic parameters of a surface soil layer will have greater influence on the displacement and excess pore water pressure than those of the subsoil layer. The traditional design method taking ground soil as homogeneous isotropic soil is unsafe for the case of RE 1 and RG 1, so a transversely isotropic foundation model is of great significance to the design for high train velocities.     

松辽盆地三肇地区油田储层裂缝及地应力特征

在大量裂缝发育特征的观察和统计工作基础上,结合油田开发动态和古构造发育史分析等,应用岩芯古地磁定向,差应变和波速各和异性等研究方法,结果认为三肇地区扶杨油层发育的裂缝走向以近东西向为主,多具高倾角,并可构成规模较大的主裂缝,其在油田注水开发中起着不可轻视的作用。分析表明,裂缝发育的密度与砂层的厚度成反比,与构造曲率成正比。区域最大水平主应力为北西西向,近东西向裂缝为油田最有效裂缝组系。     

川西北甘溪地区吉维特阶核形石特征、成因及地质意义

川西北龙门山前甘溪地区吉维特阶发育一套厚2~3m灰-深灰色微生物岩,由直径0.1~4.0cm的核形石组成,其核心皆由早期葛万藻及其他生物碎屑组成,包壳由具同心圈层结构的亮色和暗色含葛万藻的纹层组成,并可分为球状、帽状和变形状3类核形石微生物岩,垂向上可分4个旋回,从底到顶核形石密度和粒径总体变密、变大,平面上呈不均匀发育。核形石样品具不同程度的δ~(13)C、δ~(18)O值负偏移和~(87)Sr/~(86)Sr正偏移特征,表明核形石微生物岩层遭受过古表生期大气淡水的影响,其中亮色纹层与球状核形石微生物岩受大气淡水影响最为强烈,核形石是在葛万藻发育、水流扰动及大气淡水参与的环境下,葛万藻包覆于生屑的外缘而成,藻类越发育、水体能量越高、沉积环境越稳定,形成的核形石粒径越大、丰度越高。核形石微生物岩在纵、横向分布特征,表明在全球中泥盆统艾菲尔期—吉维特期海平面上升背景下,龙门山地区吉维特金宝石组末期表现为至少6期次脉动式且逐渐强烈的构造抬升作用,造成该地区金宝石组末期海平面大幅下降而暴露于地表遭受大气淡水的淋滤作用。     

Research on the Effects of the Contents of Radioactive Elements on Granularity and Climate Change： An Example of SZK1 and SZK2 Drill Holes Strata in the Fuzhou Basin

INTRODUCTIONFuzhou basin is a faulted basin developed during the mid-late Quaternary,filled with marine ,terrestrial and alternating marine-terrestrial facies sediments (Lin,1979 ;Lan,et al .,1986 ; Han,etal .,1992 ;Ding,et al .,1992 ; Wang,et al .,2000 ; Wang,et al .,2002) .Inthe basin,concealedfaults are distributed. With the support of a project entitled“Testing exploration of active fault inurban area”of the National Development and ReformCommission,two drill holes (SZK1 and S…     

航空影像的模糊增强方法

根据航空影像的灰度特性,选用像素的相对灰度等级作为模糊特征,采用模糊算法实现航空影像的模糊增强处理。实验表明,模糊算法较传统方法可取得更好的增强效果。     

鄱阳湖洲滩湿地植物演替对土壤微生物量的影响

湿地植物演替对土壤微生物量具有显著影响,但不同土壤理化环境下的植物演替对湿地土壤微生物量影响的具体差异还不清楚。以鄱阳湖土壤理化性质不同的4个碟形子湖(包括相对肥沃的东湖和白沙湖以及相对贫瘠的蚌湖和大湖池)为研究对象,运用空间代替时间的方法,在泥滩带、湿生植被带(苔草)和挺水植被带(南荻或芦苇)采集0～10 cm表层土壤,分析不同土壤理化性质条件下植物群落演替对土壤微生物量的影响。采用土壤微生物量碳(MBC)和微生物熵(qMB)指示土壤微生物量。蚌湖、大湖池、东湖和白沙湖洲滩湿地表层土壤MBC的平均值分别为1077.27、888.29、942.45和1162.46 mg/kg,土壤qMB的平均值分别为6.07%、6.17%、3.60%和3.79%。在泥滩—苔草—南荻植物演替洲滩,土壤MBC先增加后减少;但是在泥滩—苔草—芦苇植物演替洲滩,土壤MBC持续增加。植物演替没有显著改变土壤qMB。尽管植物的生长会增加所有洲滩湿地的土壤MBC,但增加的幅度在相对贫瘠的蚌湖和大湖池明显强于相对肥沃的东湖和白沙湖。蚌湖和大湖池的土壤qMB也显著高于东湖和白沙湖。在植被演替梯度上,洲滩湿地土壤MBC和...     

基于Sentinel-2A和GF-1B遥感数据的海岸带水产养殖识别方法比较

近海水产养殖为人类提供优质的动物蛋白,对海洋经济高质量发展具有重要意义。卫星遥感技术已被广泛用于海岸带水产养殖的监测,但目前相关的研究聚焦基于单一传感器卫星数据并使用单一信息提取算法而忽略与不同卫星传感器以及处理方法之间的比较。本研究以北莉岛东北部为研究区,基于多光谱Sentinel 2A卫星和高分一号B（GF 1B）卫星数据,分别使用自适应阈值法、支持向量机监督分类法以及多尺度分割面向对象分类法,开展海岸带人工水产养殖区的识别。研究表明,更高空间分辨率的GF 1B卫星对人工水产养殖水网密集区的提取正确率远优于Sentinel 2A卫星;基于高空间分辨率GF 1B卫星,多尺度分割面向对象分类法的正确率最高,为94.65%,优于支持向量机监督分类法的94.45%和自适应阈值法的84.62%;自适应阈值法更适用于中等空间分辨率卫星数据的水产养殖信息提取,其提取的水产养殖水面的面积与目视解译提取的面积差异小于4%。针对单个养殖池使用情况的业务化监测需使用高空间分辨率卫星数据,而大范围水产养殖面积的变化分析则可应用中等空间分辨率卫星数据。