检索结果-南通市图书馆

Long-term trends of precipitation and erosivity over Northeast China during 1961-2020

International soil and Water Conservation Research 2023年第4期11卷 743-754页

作者： Wenting Wang Shuiqing Yin Juan Yu Zeng He Yun Xie College of Education for the Future Beijing Normal University at ZhuhaiZhuhai519087China state Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing100875China College of Arts and sciences Beijing Normal University at ZhuhaiZhuhai519087China Zhixing College Beijing Normal University at ZhuhaiZhuhai519087China

Northeast China(NEC)is one of the vital commercial grain bases in China and it has suffered from soil erosion due to prolonged cultivation and lack of *** determine long-term trends of precipi-tation and rainfall erosivity over NEC during the latest decades,daily precipitation for the entire year during 1961-2020 and hourly precipitation for the warm season(May to September)during 1971-2020 were collected for 192 and 126 stations,*** seasons,including the cold season(October to April),early warm season(May to June),and late warm season(July to September)were divided according to the combination of precipitation and *** demonstrate:(1)Daily precipita-tion reveals total precipitation and rainfall erosivity in the cold season and early warm season increase significantly at relative rates of 3.1%-6.1%compared with the average during 1961-2020,and those in the late warm season decrease insignificantly.(2)Hourly precipitation reveals storms occurring in the early and late warm seasons have undergone significant increasing changes,which shift towards longer storm duration,larger amount,peak intensity,kinetic energy,and rainfall erosivity during ***,the frequency of extreme storms increased.(3)Rainfall erosivities estimated from daily pre-cipitation during 1971-2020 increase insignificantly for the early and late warm season,whereas those from hourly precipitation increase significantly(6.1%and 5.5%,respectively),which indicates daily precipitation may not be able to capture the trend fully under the warming background,and precipi-tation at higher resolutions than the daily scale is necessary to detect trends of rainfall erosivity more accurately.

关键词： Rainfall erosivity Climate change Storm characteristic Hourly precipitation Northeast China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of sediment on vertical dynamic impedance of rock-socketed pile with large diameter

引用

Journal of Central South university 2013年第10期20卷 2856-2862页

作者：俞缙蔡燕燕吴文兵 Geotechnical Engineering Institute Huaqiao University state Key Laboratory of Geomechanics and Geotechnical Engineering (Institute of Rock and soil Mechanics Chinese Academy of Sciences) Engineering faculty China University of Geosciences

Based on the fictitious soil pile model, the effect of sediment on the vertical dynamic impedance of rock-socketed pile with large diameter was theoretically studied by means of Laplace transform technique and impedance function transfer method. Firstly, the sediment under rock-socketed pile was assumed to be fictitious soil pile with the same sectional area. The Rayleigh-Love rode model was used to simulate the rock-socketed pile and the fictitious soil pile with the consideration of the lateral inertial effect of large-diameter pile. The layered surrounding soils and bedrock were modeled by the plane strain model. Then, by virtue of the initial conditions and boundary conditions of the soil pile system, the analytical solution of the vertical dynamic impedance at the head of rock-socketed pile was derived for the arbitrary excitation acting on the pile head. Lastly, based on the presented analytical solution, the effect of sediment properties, bedrock property and lateral inertial effect on the vertical dynamic impedance at rock-socketed pile head were investigated in detail. It is shown that the sediment properties have significant effect on the vertical dynamic impedance at the rock-socketed pile head. The ability of soil-pile system to resist dynamic vertical deformation is weakened with the increase of sediment thickness, but amplified with the increase of shear wave velocity of sediment. The ability of soil pile system to resist dynamic vertical deformation is amplified with the bedrock property improving, but the ability of soil-pile system to resist vertical vibration is weakened with the improvement of bedrock property.

关键词： rock-socketed pile sediment dynamic impedance fictitious soil pile model large diameter Rayleigh-Love rode model

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

Mechanism of frost heave by film water migration under temperature gradient

引用

Chinese science Bulletin 1997年第15期42卷 1290-1294页

作者： Xu, XZ Wang, JC Zhang, LX Deng, YS Chuvilin, EM Yershov, ED Ishizaki, T Fukuda, M state Key Laboratory of Frozen soil Engineering Lanzhou Institute of Glaciology and Geocryology Chinese Academy of Sciences Lanzhou China Geological faculty of Moscow university Russia Institute of Low Temperature science Hokkaido University Japan

IT is well known that there exists unfrozen film water in frozen soils due to the action of sur-face energy among soil particles and frost heave occurs by water migration under the tempera-ture gradient. The problem is how to determine the amount of frost heave quantitatively. The amount of frost heave induced by ice segregation can be calculated by the following e-quations:

关键词： temperature gradient film water frost heave.

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

Review and prospect of soil compound erosion

引用

Journal of Arid Land 2023年第9期15卷 1007-1022页

作者： YANG Wenqian ZHANG Gangfeng YANG Huimin LIN Degen SHI Peijun state Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China faculty of Geographical science Beijing Normal UniversityBeijing 100875China Academy of Disaster Reduction and Emergency Management Ministry of Emergency Management and Ministry of EducationBeijing Normal UniversityBeijing 100875China College of Land and Tourism Luoyang Normal UniversityLuoyang 471934China School of Business Wenzhou UniversityWenzhou 325035China Academy of Plateau science and Sustainability Qinghai Normal UniversityXining 810016China

soil erosion is one of the most serious environmental issues constraining the sustainable development of human society and *** compound erosion is the result of the alternation or interaction between two or more erosion *** recent years,fluctuations and extreme changes in climatic factors(air temperature,precipitation,wind speed,etc.)have led to an increase in the intensity and extent of compound erosion,which is increasingly considered in soil erosion ***,depending on the involvement of gravity,compound erosion process can be divided into compound erosion with and without *** systematically summarized the research on the mechanisms and processes of alternating or interacting soil erosion forces(wind,water,and freeze-thaw)considering different combinations,combed the characteristics of compound erosion in three typical regions,namely,high-elevation areas,high-latitude areas,and dry and wet transition regions,and reviewed soil compound erosion research methods,such as station observations,simulation experiments,prediction models,and artificial neural *** soil erosion model of wind,water,and freeze-thaw interaction is the most significant method for quantifying and predicting compound ***,it is proposed that there are several issues such as unclear internal mechanisms,lack of comprehensive prediction models,and insufficient scale conversion methods in soil compound erosion *** is also suggested that future soil compound erosion mechanism research should prioritize the coupling of compound erosion forces and climate change.

关键词： soil compound erosion soil erosion gravity erosion wind and water erosion freeze-thaw erosion

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

A framework for coupled consolidation-desiccation behaviour of clay slurries

引用

International Journal of Mining science and Technology 2018年第2期28卷 275-280页

作者： Faseel S.Khan Shahid Azam faculty of Engineering and Applied science University of Regina

A framework is proposed to understand coupled consolidation-desiccation in clay slurries using effective stress and soil suction as state variables. Constitutive surfaces were derived from best-fit equations for reference curves where one state variable was kept at 1 kPa and the other was varied up to 10~6 *** indicated that volume compressibility comprises of apparent pre-consolidation up to 100 kPa beyond which a single best-fit curve is valid. Similarly, the theoretical virgin compression line(specific gravity dependant), indicated that both state variables have the same effect up to the air entry value(1000 kPa at a void ratio of 1.8) beyond which void ratio reduces more readily under effective stress than under soil suction. Likewise, hydraulic conductivity remained saturated up to the air entry value and varied from 10^(-9)m/s to 10^(-12)m/s. Finally, the unsaturated hydraulic conductivity correlated well with empirical relationship up to 10^(-14) m/s bevond which vapor flow became dominant.

关键词： Clay slurries volume compressibility Hydraulic conductivity Constitutive surfaces

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

Reduction of N2O emissions by DMPP depends on the interactions of nitrogen sources(digestate vs. urea) with soil properties

引用

Journal of Integrative Agriculture 2023年第1期22卷 251-264页

作者： LI Hao-ruo SONG Xiao-tong Lars RBAKKEN JU Xiao-tang College of Resources and Environmental sciences China Agricultural UniversityBeijing 100193P.R.China state Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085P.R.China College of Tropical Crops Hainan UniversityHaikou 570228P.R.China faculty of Chemistry Biotechnology and Food ScienceNorwegian University of Life Science(NMBU)Ås 1430Norway

The inhibition of nitrification by mixing nitrification inhibitors(NI)with fertilizers is emerging as an effective method to reduce fertilizer-induced nitrous oxide(N_(2)O)*** additive 3,4-dimethylpyrazole phosphate(DMPP)apparently inhibits ammonia oxidizing bacteria(AOB)more than ammonia oxidizing archaea(AOA),which dominate the nitrification in alkaline and acid soil,***,the efficacy of DMPP in terms of nitrogen sources interacting with soil properties remains *** therefore conducted a microcosm experiment using three typical Chinese agricultural soils with contrasting pH values(fluvo-aquic soil,black soil and red soil),which were fertilized with either digestate or urea in conjunction with a range of DMPP *** the alkaline fluvo-aquic soil,fertilization with either urea or digestate induced a peak in N_(2)O emission(60μg N kg^(-1)d^(-1))coinciding with the rapid nitrification within 3 d following *** almost eliminated this peak in N_(2)O emission,reducing it by nearly 90%,despite the fact that the nitrification rate was only reduced by 50%.In the acid black soil,only the digestate induced an N_(2)O emission that increased gradually,reaching its maximum(20μg N kg^(-1)d^(-1))after 5–7 *** nitrification rate and N_(2)O emission were both marginally reduced by DMPP in the black soil,and the N_(2)O yield(N_(2)O-N per NO2–+NO3–-N produced)was exceptionally high at 3.5%,suggesting that the digestate induced heterotrophic *** the acid red soil,the N_(2)O emission spiked in the digestate and urea treatments at 50 and 10μg N kg^(-1)d^(-1),respectively,and DMPP reduced the rates substantially by nearly 70%.Compared with 0.5%DMPP,the higher concentrations of DMPP(1.0 to 1.5%)did not exert a significantly(Psoils(either with digestate or urea).This study highlights the importance of matching the nitrogen sources,soil properties and NIs

关键词： nitrous oxide digestate urea nitrification inhibitors DMPP alkaline soils acid soils

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

Toxicological and histopathological effects of Dennettia tripetala seed used as grain protectant,food,and medicine

引用

Food Quality and Safety 2017年第3期1卷 211-219页

作者： Luke Chinaru Nwosu Chris Olukayode Adedire Emmanuel Oludele Ogunwolu Michael Olufemi Ashamo Food Technology Programme Department of BiologyFederal University of TechnologyAkureOndo State and Department of Crop and Environmental Protection University of AgricultureMakurdiBenue StateNigeria Department of Crop and soil science Faculty of AgricultureUniversity of Port HarcourtP.M.B.5323Port HarcourtRivers StateNigeria

The study revealed the safety of Dennettia tripetala seed on man and the *** male rats weighing 0.158-0.168 kg housed in standard cages with free access to food and water were used for the *** median lethal dose(LD50)was estimated using revised up and down *** LD50 for *** seed extract was 5785 mg/kg and this evoked paralysis in rats for 4 days coupled with discharge from the eyes and eventual *** least weight gain by the animals administered 75%seed powder of ***(4338.75 mg/kg)was an index of high powder concentration,whereas the weight loss experienced by group v animals is strongly attributed to chemical assault by permethrin designated as a standard *** high values of alanine aminotransferase(ALT),aspartate aminotransferase(AST),and urea in the groups administered 75%permethrin powder(4338.75 mg/kg)and 75%*** seed powder is an index of liver and kidney injury and *** presence of normal serum levels of ALT,AST,alkaline phosphatase,and creatinine;normal liver and kidney structures;and normal weight gains in the animal groups fed basal diet(control)and basal diet plus 25%*** is a strong indication that 25%*** seed powder(1446.25 mg/kg)supplementation is not toxic to the liver and kidney and therefore supports normal organ *** LD50 recorded strongly indicates that *** has a moderately high safety *** of less than 50%(2892.5 mg/kg)is recommended in the safe use of the plant material as grain protectant,food,and *** botanical insecticide,***,is safer than the conventional synthetic insecticide,permethrin,on account of the latter showing evidence of kidney damage.

关键词： Safety botanical insecticide permethrin supplementation kidney damage

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

state of Organic Matter and Particularities of Physicochemical Properties of soils in the Endogenous Hydrogen Seepage Zones

引用

Open Journal of soil science 2018年第8期8卷 186-196页

作者： Natalia Ivanovna Sukhanova Tatiana Aleksandrovna Zubkova faculty of soil science Lomonosov Moscow State University Moscow Russia

In the territory of the voronezh region of Russia in ordinary middle loam chernozem the elevated concentration of endogenous hydrogen streams up to 0.65% at the depth of 100 - 120 cm was detected. This phenomenon is observed in the center of depressions. The soils differ in morphological, chemical and physical properties. The top humus horizon is markedly bleached comparing to the soil outside the depression: The lightness L readings increase for 16% - 30%. The soil acidity (up to pH 4.5 - 5.0) and organic carbon content are elevated comparing to the sample for reference. The proportion of fulvic acids increases on average thrice as compared with the soils outside the hydrogen fluids influence zone. Despite the high humus content the mechanical strength of aggregates decreases 3 - 4 times. Under conditions of hydrogen fluids, changes occur at the aggregate structural level in the direction of decreasing their mechanical strength. In the center of the depressions strength of aggregates is reduced by 2 - 3 times in comparison with the control. The opposite regularity was observed in the absence of hydrogen flows, where the strength of aggregates was 3 times higher than in comparison with the control.

关键词： soil Humus Hydrogen Aggregate Structure Mechanical Strength of Aggregates Matrix Organization of soil

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

soil physical properties degrade further on skid trails in the year following operations

引用

Journal of Forestry Research 2018年第1期29卷 93-101页

作者： Ramin Naghdi Ahmad Solgi Eric K.Zenner Farshad Keivan Behjou Department of Forestry Faculty of Natural Resources University of Guilan Department of Ecosystem science and Management Penn State UniversityUniversity Park faculty of Agricultural Technology and Natural Resources University of Mohaghegh Ardabili

Short-term recovery of soil physical properties on skid trails was investigated upon cessation of skidding operations and 1 year later. Bulk density and porosity were assessed at three levels of traffic intensity and two slope gradients. Compared to undisturbed areas, bulk density increased, total porosity and macroporosity decreased, and microporosity increased in the compacted areas immediately after skidding. In all cases, changes were significantly greater when traffic intensity was higher and when slopes were steeper. Surface soil compaction did not show any recovery over the 1-year period, illustrating the persistent effects of compaction on soil structure. In fact, surficial compaction further increased and macroporosity further decreased after 1 year of recovery, compared to immediately after skidding. While these changes may reflect inherent small-scale site variability or differences in soil moisture content at times of sampling, direct negative physical impacts on newly exposed soil（such as by raindrops）, in addition to the loss of organic matter after canopy removal and skidding, likely delayed any physical recovery, particularly on heavily trafficked trails on steeper slopes. These results raise serious concerns about longterm resilience to traffic on forest soils and indicate the necessity to properly retire skid trails to avoid further soil degradation as trails age.

关键词： Compaction Porosity Recovery Skid trail slope Traffic frequency

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

Parametric sensitivity analysis of precipitation and temperature based on multi-uncertainty quantification methods in the Weather Research and Forecasting model

引用

science China Earth sciences 2017年第5期60卷 876-898页

作者： DI ZhenHua state Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical Science Beijing Normal University Beijing 100875 China Institute of Land Surface System and Sustainable Development Faculty of Geographical Science Beijing Normal University Beijing 100875

Sensitivity analysis(SA) has been widely used to screen out a small number of sensitive parameters for model outputs from all adjustable parameters in weather and climate models, helping to improve model predictions by tuning the parameters. However, most parametric SA studies have focused on a single SA method and a single model output evaluation function, which makes the screened sensitive parameters less comprehensive. In addition, qualitative SA methods are often used because simulations using complex weather and climate models are time-consuming. Unlike previous SA studies, this research has systematically evaluated the sensitivity of parameters that affect precipitation and temperature simulations in the Weather Research and Forecasting(WRF) model using both qualitative and quantitative global SA methods. In the SA studies, multiple model output evaluation functions were used to conduct various SA experiments for precipitation and temperature. The results showed that five parameters(P3, P5, P7, P10, and P16) had the greatest effect on precipitation simulation results and that two parameters(P7 and P10) had the greatest effect for temperature. Using quantitative SA, the two-way interactive effect between P7 and P10 was also found to be important, especially for precipitation. The microphysics scheme had more sensitive parameters for precipitation, and P10(the multiplier for saturated soil water content) was the most sensitive parameter for both precipitation and temperature. From the ensemble simulations, preliminary results indicated that the precipitation and temperature simulation accuracies could be improved by tuning the respective sensitive parameter values, especially for simulations of moderate and heavy rain.

关键词：参数敏感性分析温度模拟降水不确定性气候模型量化评价函数调整参数

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

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：