Experimental study of migration of potassium ion through a two-layer soil system     

Yan Jun Du  Shigenori Hayashi  Song Yu Liu 《Environmental Geology》2005,48(8):1096-1106

A barrier system based on the hydraulic trap design concept for a landfill was proposed. To study the field scenario in which a clay liner is underlain by a granular layer functioning as a secondary leachate drain layer, a laboratory advection–diffusion test was performed to investigate factors controlling the transport of contaminants in a two-layer soil system. The soils used for this study were Ariake clay and, the underlying layer, Shirasu soil from the Kyushu region of Japan. Potassium (K⁺) was selected as the target chemical species with an initial concentration of 905 mg L⁻¹. The effective diffusion coefficients (D _e) of K⁺ for Ariake clay and Shirasu soil were back-calculated using an available computer program, Pollute V 6.3. Values of D _e derived from this experiment are consistent with previously published ones. The Ariake clay has lower D _e than the Shirasu soil. The hypothesis that mechanical dispersion can be considered negligible is reasonable based on both the observation that the predicted values well fit the experimental data and the analyses of two dimensionless parameters. Parametric analyses show that transport of K⁺ through soils is controlled by advection–diffusion rather than diffusion only, whereas at low Darcy velocity (i.e., ≤10⁻⁹ m s⁻¹), transport of K⁺ will be controlled by diffusion. Applications of the test results and parametric analysis results in practical situations were reviewed.  相似文献   

Environmental properties of metallic minerals and their applications in environmental protection in China     

王吉中李胜荣  江永宏魏瑞华 牛花朋 《中国地球化学学报》2005,24(3):221-227

In terms of environmental mineralogy, the environmental properties of metallic minerals, including chemical activation, adsorption, pore effect and nanometer effect, have been analyzed. On the basis of the analysis of environmental properties of metallic minerals, the applications of iron-bearing sultides, iron and manganese oxides in the purification of wastewaters containing heavy metal ions （Cr^6＋ ,Hg^2＋ , Pb^2＋ , etc. ） have been summarized. Moreover, research on the application of metallic minerals in environmental protection has been anticipated. It should be a piece of dominating work for environmental mineralogie researchers in the future to lucubrate systematically the physical and chemical characteristics of the metallic mineral surfaces, further reveal the reciprocity process between metallic minerals and water surface, perfect the theory and model of the metallic minerals to remove contaminants, intensify study on the facilities and techniques of metallic minerals to remove contaminants, and entail well the extension and propagation of achievements.  相似文献   

土-箱形基础-框架结构相互作用的顶部小幅激振试验研究     

尚守平朱志辉  吴方伯杜运兴 《地震工程与工程振动》2006,26(5):243-251

设计并完成了野外大比例(1∶2)土-箱形基础-框架结构相互作用系统顶部小幅激振试验。通过改变上部结构质量和基础侧限埋深,激振试验得到了同一基础不同上部结构质量与同一上部结构不同基础侧限埋深等5种工况下相互作用对系统自振频率及箱形基础阻抗函数的影响。由试验结果分析可知,当上部结构质量增加时,上部结构与土体间的相对刚度降低,相互作用对系统自振频率的影响减弱;同时由于上部结构和基础间惯性相互作用的影响,基础阻抗函数随上部结构质量的增加而增加。随着基础侧限埋深的减小,基础刚度降低,相互作用体现得更加明显。与理论结果相比,无侧限埋深基础的平动和转动基础阻抗值和理论值吻合较好。由于基础侧边回填土剪切模量小于基础底部土体剪切模量,所以同理论值相比试验得到的基础侧限埋深对基础阻抗影响系数相对较小。  相似文献   

Karst groundwater management by defining protection zones based on regional geological structures and groundwater flow fields   总被引：2，自引：0，他引：2  

Yonghong Hao  Tian-Chyi J. Yeh  Caihong Hu  Yanrong Wang  Xia Li 《Environmental Geology》2006,50(3):415-422

In a semiarid region, the karst aquifer generally forms a large groundwater reservoir that can play an important role in regional water supply. But because of the specific physical properties of karst aquifers, they are vulnerable to pollution and anthropogenic impacts. Karst groundwater management strategies are vital. As representative of karst springs in a semiarid area, Niangziguan Springs is located in the east of Shanxi Province, China with an annual average rate of discharge of 10.34 m³/s (1956–2003) (Y. Liang, unpublished data). The Niangziguan Spring Basin covers an area of 7,394 km² with an annual average precipitation of 535 mm (1958–2003) (Hao et al. in Carsologica Sinica 23(1):43–47, 2004). Over the past three decades, accelerated groundwater exploitation has caused water-table decline in the aquifer, reduction of the spring discharge, and deterioration of water quality. In this study, three protection zones were defined to ensure the quality and capacity of this resource. The confluence of the 11 spring systems and the discharge areas were defined as I protection zone, the recharge basin was II protection zone, and the slack water area where there is little surface recharge was the III protection zone. Management strategies for each zone were suggested and evaluated to provide a scientific foundation for sustainable utilization.  相似文献   

南海成因研究现状   总被引：1，自引：0，他引：1  

邓希光吴庐山  杜德莉 《南海地质研究》2006,(1):21-29

南海作为西太平洋边缘海中最大的海盆，其成因与欧亚板块、太平洋板块和印度-澳大利亚板块密切相关，而且也是世界上重要的油气产区，成为国内外地质学家长期研究的热点地区之一。本文在前人研究的基础上对南海成因模式进行概括和总结，在此基础上讨论了南海成因模式存在的问题以及今后应重点研究的方面。  相似文献   

用红外云图估算热带气旋短时雨量     

胡波  杜惠良  滕卫平  肖云 《气象》2006,32(1):74-77

以热带气旋降水云区的云顶亮温和1小时云顶亮温差为BP人工神经网络的输入层，以实况1小时的雨量为人工神经网络的输出层，建立了4类人工神经网络预报模型，分别为点模型、线模型、小面模型和大面模型。通过大量的人工神经网络试报表明小面模型能较好地抓住热带气旋红外云图中的主要降水影响因子（移向、移速、云顶亮温、发展率、云顶亮温梯度），具有“过拟合”现象低、泛化性能高、预报能力强等特点。  相似文献   

近116年江淮梅雨异常及其环流特征分析   总被引：6，自引：3，他引：6  

毛文书  王谦谦  葛旭明  景艳  杜宜翠  曹艳艳 《气象》2006,32(6):85-90

利用江淮地区1885—2000年近116a梅雨特征量资料和NCEP／NCAR逐日再分析资料，采用谐波分析、最大熵谱分析、小波分析、合成分析等方法讨论了江淮梅雨特征量的年际-年代际变化特征及梅雨异常的环流特征。结果表明；江淮梅雨特征量存在显著的年际和年代际变化特征。入梅日期、出梅日期、梅雨期长度呈显著上升的长期变化趋势，梅雨量和梅雨强度长期趋势变化不明显；梅雨特征量均存在多时间尺度的振荡周期，入梅日期具有准24a、准5a和准3a的显著周期；出梅日期具有准35a、准22a和准5a的显著周期；梅雨量具有准40a、准15a、准9a和准3a的显著周期。丰梅年南亚高压中心强度和西太平洋副热带高压增强。枯梅年则反之。  相似文献   

鄂尔多斯盆地中部上三叠统延长组物源方向分析与三角洲沉积体系   总被引：85，自引：8，他引：77       下载免费PDF全文

宋凯  吕剑文  杜金良  王宏科 《古地理学报》2002,4(3):59-66

首次利用稀土元素和微量化学元素,分析鄂尔多斯盆地中部上三叠统延长组母岩类型和物源方向。研究表明盆地中部延长组砂岩和泥岩的稀土元素地球化学特征、REE分配模式及微量化学元素蜘蛛图解相同,表现为轻稀土富集,重稀土亏损,铕、铈元素亏损;REE分配模式均呈“右倾斜、LREE富集、HREE平坦”型;微量化学元素蜘蛛图解具“四峰三谷一平台”型,曲线呈阶梯状分布;砂岩和泥岩的地球化学特征、REE分配模式及微量化学元素蜘蛛图解与盆地东北缘的太古代、元古代变质岩相一致,而与火成岩的重稀土富集、轻稀土亏损、“V”字型REE分配模式和“三峰两谷”型、曲线呈“W”字型分布的蜘蛛图解的特征有显著的差别。说明延长组母岩是盆地东北缘的太古代、元古代变质岩,主要物源方向为北东向。依据物源方向、沉积环境、砂岩岩石学特征、砂岩稀土元素和微量化学元素的地球化学特征,将鄂尔多斯盆地中部上三叠统延长组沉积划分为两大三角洲沉积体系,即北东向的安塞三角洲沉积体系、志靖三角洲沉积体系、安边三角洲沉积体系和北西向的盐定三角洲沉积体系。在三角洲沉积体系划分的基础上,详细阐述了不同三角洲沉积体系的岩石学特征、稀土元素和微量化学元素的地球化学特征及延长组长6-长2期三角洲沉积体系的演化过程。  相似文献   

Interaction between subducted continental crust and the mantle     

Shuguang Li  Yonghong Nie  Deliang Liu  Shuanggen Zheng 《中国科学D辑(英文版)》1998,41(5):545-552

The syncollisional mafic-ultramafic intrusions in the North Dabie terrane are characterized by enriched LREE, Rb, Ba, and depletion of high field strength elements, such as Nb, Zr, Ti. The high Ti/& and Ti/Y ratios of their parent magma suggest that crust contamination of magma is not important to the above trace elements characters. They mainly reflect the features of their mantle source which has been modified by metasomatism in subduction environment.  相似文献   

空间信息的结构、表达及其理解机制     

杜清运 《武汉大学学报(信息科学版)》1998,(4)

在分析传统地理信息系统理论主要缺陷的基础上,将语言学引入地理信息系统,提出了数字环境下空间信息结构与表达的认识模型——空间信息的语言学模型,探讨了空间信息的语言学特征,主要是语言单位、语法及语义机制,并就其对地理信息系统各环节特别是空间信息的智能化数据处理所产生的影响进行了讨论。  相似文献