检索结果-南通市图书馆

^(137)Cs Redistribution in Thin Stony soil of a Carbonate rock Slope in Southwest china

Pedosphere 2011年第1期21卷 37-45页

作者： LI Hao ZHANG Xin-Bao WANG Kc-Lin WEN An-Bang institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 (China) Graduate University Chinese Academy of Sciences Beijing 100049 (China) State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 (China) institute of Subtropical Agriculture Chinese Academy of Sciences Changsha 410125 (China)

The fallout radionuclide cesium-137(137 Cs) has been widely employed as a tracer for assessment of soil loss from thick uniform soils;however,few studies have been conducted on thin stony soils on slopes underlain by carbonate rocks which are widely distributed in karst *** derived from 137 Cs measurement of soil samples collected along a carbonate rock slope with thin stony soil where neither soil erosion nor deposition occurred was used to investigate the characteristics of 137 Cs redistribution in a karst area of Southwest *** results indicated that the 137 Cs inventories of the surface soil on the slope studied were much lower than that of the local 137 Cs reference inventory and the 137 Cs activities were much higher than those on slopes with thick uniform *** spatial distribution of 137 Cs inventories was characterized by considerable *** high 137 Cs depletion in the stony soil of the slope studied was mainly because a considerable proportion of the fallout input of 137 Cs could be lost with runoff and the dissolution of carbonate particles in the soil promoted the loss of 137 *** demonstrated that the rates of soil loss could not be estimated from the degree of depletion of the 137 Cs inventory relative to the local reference inventory for the thin stony soil of the rocky slope underlain by carbonate rocks in the study area in the way that has been widely used in areas with thick uniform soils.

关键词： carbonate dissolution, ^137Cs fallout, ^137Cs inventory karst area runoff

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

遍布节理对地下洞室群围岩稳定性的影响研究

引用

土木工程学报 2009年第9期42卷 96-103页

作者：冷先伦盛谦朱泽奇张勇慧中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室湖北武汉430071

因地质条件的复杂性,导致节理、断层、裂隙等弱面较为发育,致使在对大型地下洞室群围岩稳定性研究中很难全面考虑各弱面对稳定性的影响,因此我们通过引入遍布节理模型,同时考虑岩块和节理属性,使研究更加符合岩体状态及工程实际。介绍... 详细信息

因地质条件的复杂性,导致节理、断层、裂隙等弱面较为发育,致使在对大型地下洞室群围岩稳定性研究中很难全面考虑各弱面对稳定性的影响,因此我们通过引入遍布节理模型,同时考虑岩块和节理属性,使研究更加符合岩体状态及工程实际。介绍可考虑岩体中节理弱面的遍布节理弱面模型及其在有限差分程序中的实现,选取佛子岭抽水蓄能水电站地下厂房洞室群作为工程实例,对比分析洞室围岩在莫尔-库伦模型和遍布节理模型两种条件下的位移、应力状态和塑性区发展情况。在引入遍布节理模型后,洞室壁水平位移值增长显著,主应力值有一定程度增加,而围岩顶拱和底板变化不明显,只略有加大,在洞室交接处,应力集中现象较明显。运用正交设计方法,选取六种不同走向和倾向的遍布节理弱面,研究遍布节理弱面的走向和倾向对围岩变形的影响。研究结果表明,遍布节理弱面对地下洞室群围岩稳定性有较大影响,当其方向与断层弱面方向垂直且与洞室群成斜交时,影响最大。

关键词：遍布节理模型地下洞室群围岩稳定正交设计 FLAC^3D

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

soil water characteristics in mountain poplar stand and its benefits to soil and water conservation in loess hilly region

引用

Journal of Environmental sciences 1994年第3期6卷 347-354页

作者： Wu Qinxiao Liu Xiangdong Zhao Hongyan Northwestern institute of soil and Water Conservation,chinese academy of sciences and Ministry of Water Conservancy),Yangling 712100,china)

The soil physical properties,its water characteristics and the benefits to soil and water conservation in mountain poplar stand were determined and studied. The results of the study show that the compaction in soil profile is relatively *** specific gravity and volume weight of soil increase with deepening of soil horizon. The water infiltration rate of soil in the stand is 17,6 times as high as in *** to the intense absorption of water by root system of plants,a drying layer is formed in soil horizon from 2.3 m to 2.7m,showing that the subsoil moisture is in the state of deficit. The annual water storage capacity in 2 m of soil horizon is 360 mm 370mm,or 63% 65% of annual precipitation. Compared with farmland,mountain poplar stand reduces the surface runoff and soil loss by 70% and 99%,respectively,indicating the great benefits to soil and water conservation.

关键词： mountain poplar soil water characteristics soil and water conservation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Influence of rock Block Contents on Geo-Mechanical Behavior of soil-rock Mixture

The Influence of Rock Block Contents on Geo-Mechanical Behav...

引用

2012颗粒材料计算力学会议

作者： Liu Yi-Ming State Key Laboratory of Geomechanics and Geotechnical Engineering,institute of rock and soil mechanics,chinese academy of sciences,wuhan 430071,china

soil-rock mixtures(SRM) is a special geomaterical which is composed of soil and rock *** toits natural characteristics of inhomogeneity and discontinuity,there are still many difficulties about understandingmechanical properties of the SRM *** paper presents a particle-scale investigation of geomechanicalbehavior of the SRM material by the discrete element method(DEM).A series of numerical triaxial compressiontests are carried out to study the influence of different ratios of rock block in SRM on the stress-strain behavior,thevolumetric response and on the macroscopic properties such as friction angle and dilation *** is shown that theratio of rock block content in SRM

关键词： soil-rock mixtures discrete element method geo-mechanical behavior equivalent skeleton void ratio

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Discontinuous deformation analysis based on complementary theory

引用

Science china(Technological sciences) 2009年第10期52卷 2547-2554页

作者： ZHENG Hong1,2 & JIANG Wei2 1 china Three Gorges University,Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education, Yichang 443002,china 2 State Key Laboratory of Geomechanics and Geotechnical Engineering,institute of rock and soil mechanics,chinese academy of sciences,wuhan 430071,china 1. china Three Gorges University Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of Education Yichang 443002 China 2. State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China

The contact between blocks is treated by the open-close iteration in the conventional discontinuous deformation analysis (DDA),which needs to introduce spurious springs between two blocks in contact and to assume the normal stiffness and the tangential stiffness (the penalty factors). Unreasonable values of stiffness would result in numerical problems. To avoid the penalty factors and the open-close iteration,we reformulate the DDA as a mixed complementary problem (MiCP) and then choose the path Newton method (PNM) to solve the problem. Some examples including those originally designed by Shi are reanalyzed,which proves feasibility of the proposed procedure.

关键词： discontinuous deformation analysis (DDA) contact problems open-close iteration complementary theory non-smooth analysis

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Experimental investigation and numerical simulation on the effect of fissure water pressure in vertical sliding surface

引用

Science china(Technological sciences) 2005年第z1期48卷 53-64页

作者： ZHANG Lei1,2, LI Shihai1, LIAN Zhenzhong1,2 & WANG Yuannian1 1. institute of mechanics, chinese academy of sciences, Beijing 100080, china 2. Graduate School, chinese academy of sciences, Beijing 100060, china 1. institute of mechanics Chinese Academy of Sciences 100080 Beijing China 2. Graduate School Chinese Academy of Sciences 100060 Beijing China

This paper studies the effect of fissure water pressure in different fractures on the critical angle of landslide by laboratory investigation and numerical simulation in order to understand the mechanisms of fissure water pressure on landslide stability. Laboratory observations show that the effect of fissure water pressure on the critical angle of landslide is little when the distance between water-holding fracture and slope toe is three times greater than the depth of fissure water. These experimental results are also simulated by a three-dimensional face-to-face contact discrete element method. This method has included the fissure water pressure and can accurately calculate the critical angle of jointed slope when fissure water pressure in vertical sliding surface exists. Numerical results are in good agreement with experimental observations. It is revealed that the location of water-holding structural surface is important to landslide stability. The ratio of the distance between water-holding fissure and slope toe to the depth of fissure water is a key parameter to justify the effect of fissure water pressure on the critical angle of landslide.

关键词： jointed rock slope, discrete element method, fracture in vertical sliding surface, model experiment,fissure water pressure.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Nitrate Accumulation in soil Profile of Dry Land Farming in Northwest china

引用

Pedosphere 2003年第4期13卷 367-374页

作者： FAN Jun, HAO Ming-De and SHAO Ming-AnState Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau, institute of soil and Water Conservation, the chinese academy of sciences, Yangling 712100 (china). State Key Laboratory of soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation the Chinese Academy of Sciences Yangling 712100 China

A long-term fertilizer experiment on dry land of the Loess Plateau, northwestchina, has been conducted since 1984 to study the distribution and accumulation of NO_3-N down to adepth of 400 cm in the profile of a coarse-textured dark loessial soilafter continuous winter wheatcropping. Thirteen fertilizer treatments consisted of four levels of N and P applied alone or incombination. Annual N and P (P_2O_5) rates were 0, 45, 90, 135 and 180 kg ha^(-1). After 15successive cropping cycles, the soil samples were taken from each treatment for analysis of NO_3-Nconcentration. The results showed that NO_3-N distribution in the soil profile was quite differentamong the treatments. The application of fertilizer N alone resulted in higher NO_3-N concentrationin the soil profile than the combined application of N and P, showing that application of P couldgreatly reduce the NO_3-N accumulation. With an annual application of 180 kg N ha^(-1) alone, a peakin NO_3-N accumulation occurred at 140 cm soildepth, and the maximum NO_3-N concentration in thesoils was 67.92 mg kg^(-1). The amount of NO_3-N accumulated in the soil profile decreased as thecumulative N uptake by the winter wheat increased. Application of a large amount of N resulted inlowerN recoveries in winter wheat and greater NO_3-N accumulation in soil profile. KO_3-N did notenter underground water in the study region; therefore, there is no danger of underground waterpollution. Amount of NO_3-N accumulation can be predicted by an equation according to annual N and Prates based on the results of this experiment.

关键词： dry land long-term fertilizer experiment NO_3-N accumulation wheat

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Pedosphere and Its Effect on Global Changes

引用

Pedosphere 2000年第2期10卷 97-106页

作者： ZHAO QIGUO and CAO HUI(institute of soil Science, the chinese academy of sciences, P.O. Box 821, Nauling 210008 china) 中科院南京土壤所江苏南京 210008

With development of modern geoscience, particularly development of environmental sciences, the contemporary soil science is undergoing great changes in both research contents and scope. soil is not onlya certain substance or a certain independent natural historical body but also a spheric layer with peculiarstructure and functions in the earth system. From the viewpoint of the geo-biosphere system of earth, soilscience does deal not only with the soil substances per se but also more importantly with the relationshipsamong soil, the other spheres and the human survival environment in view of the "pedosphere". This is thenew orientation of soil science today and will affect profoundly the studies on the human survival environmentand global changes. To throw more light on this subject, the present paper intends to address the conceptionof pedosphere and its role in global changes. Also addressed are series of environmental issues in china andtheir relations to the global changes. Moreover, research orientation and priorities are indicated, includingexploitation and protection of the soil resources, soil fertility and sustainable agricultural development, construction of the ecological environment, and the material cycling in pedosphere and its relation to globalchanges.

关键词： earth ecological environment global changes pedosphere soil science

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Changes in hair arsenic concentration in a population exposed to heavy pollution:Follow-up investigation in Chenzhou City,Hunan Province,Southern china

引用

Journal of Environmental sciences 2010年第2期22卷 283-289页

作者： Bin Wu,Tongbin Chen Center for Environmental Remediation,institute of Geographic sciences and Natural Resources Research,chinese academy of sciences,Beijing 100101,china. [a] Center for Environmental Remediation Institute of Geographic Sciences Natural Resources Research Chinese Academy of Sciences Beijing 100101 China

Follow-up investigation on hair arsenic concentration was conducted in an arsenic heavily polluted area of southern china in 2002 and 2006. The results showed that the geometric mean of hair arsenic concentration decreased from 2.95 mg/kg in 2002 to 1.78 mg/kg in 2006, when the percentage of the population with levels over 1 mg/kg only decreased from 93.4% in 2002 to 80.5% in 2006. Over this four-year period, the population with high arsenic concentrations decreased significantly while there was no obvious change in hair arsenic concentration for people who had relatively low concentrations. In terms of age distribution, young and old people had higher hair arsenic concentrations than the middle-aged. All of these results showed that it is difficult to reverse the negative impact of arsenic pollution on human health. Arsenic pollution has a long-term continuous influence on the health of local residents.

关键词： arsenic human health soil contamination hair arsenic

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Daily variation of carbon flux in soils of Populus euphratica forests in the middle and lower reaches of the Tarim River

引用

Progress in Natural Science:Materials International 2007年第5期17卷 584-590页

作者： Huang Xiang , Chen Yaning , Li Weihong , Ma Jianxin and Chen Yapeng (Xinjiang institute of Ecology and Geography, chinese academy of sciences, Urumqi 830011, china Graduate University, chinese academy of sciences, Beijing 100039, china) [a]Xinjiang institute of Ecology and Geography Chinese Academy of Sciences Urumqi China [b]chinese academy of sciences Graduate University Beijing China

In order to lucubrate the daily variation of respiration in soils of Populus euphratica forests and analyze its relationship with environmental factors in the middle and lower reaches of the Tarim River, the LI-8100 instrument of soil CO2 flux system was used to measure the parameters of soil carbon flux and air temperature 10 cm above ground surface along the profiles of Usyman, Archy River, Yengisu and Karday, and the relationships between the soil carbon flux and the soil moisture content were analyzed. The nonlinear regression analysis was carried out with the software SPSS13.0. We observed that: (1) soil respiration began to be restrained when the air temperature was up to 30℃10 cm above the ground surface; (2) the rates of soil respiration under the forests of Populus euphratica were significantly different at various moisture contents, the soil carbon flux was high along the Usyman profile, which has a high soil moisture content, and it was low along the profiles of Archy River, Yengisu and Karday, which has a low soil moisture content; (3) the exponential model can be used to explain the relationship between soil respiration and air temperature 10 cm above the ground surface. The average Q10 values along the profiles of Usyman, Archy River, Yengisu and Karday are 0. 61, 0.16, 0. 22 and 0. 35 respectively, much lower than the average of the world; (4) there is a positive correlation between the soil carbon flux and the soil moisture content.

关键词： Populus euphratica soil carbon flux air temperature 10 cm above ground surface soil moisture content the Tarim River.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：