检索结果-南通市图书馆

simulated multi-scale watershed runoff and sediment production based on geoWEPP model

International Journal of sediment Research 2009年第4期24卷 465-478页

The runoff and sediment yield data from the Qiaozidonggou, Qiaozixigou, and Lu’ergou watersheds, in the Loess Plateau of china are used to calibrate and validate the runoff and sediment yield simulated by geoWEPP model of the WEPP Model at watershed scale. The indices of relative error, R, correlation coefficient, R 2 , and Nash-suttcliffe efficiency coefficient En s are used to evaluate the model fit. The eco-hydrological responses in the Luoyugou and Lu’ergou watersheds are also forecast based on the WEPP Model. Meanwhile, the relation between vegetation pattern changes and sediment yield in the watershed is discussed, and the responses of runoff and sediment yield in the watersheds concerning forest growth stages are studied. The results show that the relative errors of simulated values of runoff and sediment yield are below 3.%, the correlation coefficients are above 0.90, and the Nash-suttcliffe efficiency coefficients are above 0.80. The simulation results present satisfactory performance, thus, the model could be used to simulate the runoff and sediment yield in these small watersheds. It is also observed that soil erosion tended to become severe as precipitation increased in the watershed, while soil erosion has a decreasing trend as forest cover increases and vegetation pattern is optimized. When the watershed is fully covered by forest, erosion and sediment yield are minimized. When the forest cover is about 3.% and evenly distributed in the watershed, the erosion intensity is lower than if the forest cover is collectively distributed in the watershed. Erosion varies with different forest growth stages in the watershed; it is more serious at the young and near planting stage and is the smallest at the mature forest stage.

关键词： geoWEPP model Eco-hydrological response Watershed runoff sediment yield Model calibration Erosion modeling

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

source time-function as discriminant using empirical Green's function

引用

science china earth sciences 2005年第12期48卷 2118-2122页

作者： HE Yongfeng1,2 & CHEN Xiaofei1 1. Department of geophysics, school of earth & space sciences, Peking {3., beijing 100871, china 2. North-West Institute of Nuclear Technology, Xi’an 710024, china 1. Department of geophysics School of Earth & Space Sciences Peking University 100871 Beijing China 2. North-West Institute of Nuclear Technology 710024 Xi’an China

The source mechanism of underground nuclear explosions is remarkably different from that of earthquakes in both spatial radiation pattern and source time-function (sTF). small underground nuclear explosions can be used as empirical Green’s functions (EGF) to isolate the source-time spectrum of a large suspected earthquake occurred in a Nuclear Test site (target area) by the spectral division method. As this study shows, with high-quality data, the quotient spectrum can be transformed to the time domain, yielding the apparent far-field source-time function of the large suspected event. The relative source time-function (RsTF) of a nuclear ex-plosion is usually a simple pulse with a duration of about 1 s., while an earthquake’s is more complicated with a series of pulses and a longer duration. The RsTF can be used as a nice dis-criminant to distinguish the nature earthquakes from underground nuclear explosions in target areas.

关键词： target-area, empirical Green's function, RsTF.

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

Fabrication of pure copper rods containing continuous columnar crystals by continuous unidirectional solidification technology

引用

Journal of university of science and Technology beijing 2004年第3期11卷 240-244页

作者： Hong zhang Jianxin Xie Zidong Wang Materials science and Engineering school, university of science and Technology beijing,{3. Mat. sci. and Eng. sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Pure copper rods containing continuous columnar crystals were fabricatedusing the downward CUs (Continuous Unidirectional solidification) equipment. When the technologicalparameters were set as the ranges of mould temperature 1100-13.0℃, cooling distance (the distancefrom the exit of the cast mould to the start point of cooling) 10-20 mm, casting speed 0.2-2.5 mm/s,cooling water (20-25℃) volume 1000-13.0 L/h, and when these parameters matched reasonably, the CUsprocess was performed stably, and pure copper rods containing continuous columnar crystals withbright and smooth surface were produced. The dendritic arm spacing of the crystals in copper rodsdecreased with increasing the casting speed. The results of the texture by X-ray diffractionanalysis showed that the rods has strong fiber texture.

关键词： copper continuous unidirectional solidification mould temperature castingspeed microstructure texture

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 Design and Implementation of Qinghai Province geological Hazards Management Information system

引用

地学前缘 2009年第S1期16卷 42-43页

作者： Quan Xu~1,Qun Wang~1,Jun Chen~2,Wenqian Jiang~1 1.school of Information Technology,china university of {3.sciences(beijing),beijing 100083.china. 2.Department of Information,china Institute of {3.-Environment Monitoring,beijing 100081,china

The formation and development of geological hazards are extremely complex,depending on factors such as the topography,geology,meteorology, project,human activity,and so on;the geological hazards data include remarkable spatial characteristics and complex attribute *** the amount of geological hazards data is rapidly growing,it has become an urgent demand for geologists to

关键词： geological hazards mapGIs web services ajax

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

Main progress and problems in research on Ordovician hydrocarbon accumulation in the Tarim Basin

引用

Petroleum science 2010年第2期7卷 147-163页

作者： Pang Xiongqi Tian Jun Pang Hong Xiang Caifu Jiang Zhenxue Li sumei Basin and Reservoir Research Center School of Natural Resources and Information Technology China University ofPetroleum Beijing 102249 China state Key Laboratory of Petroleum resources and Prospecting China University of Petroleum Beijing 102249 China Petrochina Tarim Oilfield Company Korla Xinjiang 841000 China

The Tarim Basin is the largest petroliferous basin in the northwest of china, and is composed of a Paleozoic marine craton basin and a Meso-Cenozoic continental foreland basin. It is of great significance in exploration of Ordovician. In over 50 years of exploration, oil and gas totaling over 1.6 billion tonnes oil-equivalent has been discovered in the Ordovician carbonate formation. The accumulation mechanisms and distribution rules are quite complicated because of the burial depth more than 3.500 m, multi-source, and multi-stage accumulation, adjustment, reconstruction and re-enrichment in Ordovician. In this paper, we summarized four major advances in the hydrocarbon accumulation mechanisms of Ordovician carbonate reservoirs. First, oil came from Cambrian and Ordovician source rocks separately and as a mixture, while natural gas was mainly cracked gas generated from the Cambrian-Lower Ordovician crude oil. second, most hydrocarbon migrated along unconformities and faults, with different directions in different regions. Third, hydrocarbon migration and accumulation had four periods： Caledonian, early Hercynian, late Hercynian and Himalayan, and the latter two were the most important for oil and gas exploration. Fourth, hydrocarbon accumulation and evolution can be generally divided into four stages： Caledonian （the period of hydrocarbon accumulation）, early Hercynian （the period of destruction）, late Hercynian （the period of hydrocarbon reconstruction and re-accumulation）, and Himalayan （the period of hydrocarbon adjustment and re-accumulation）. source rocks （s）, combinations of reservoir-seal （C）, paleo-uplifts （M）, structure balance belt （B） matched in the same time （T） control the hydrocarbon accumulation and distribution in the Ordovician formations. Reservoir adjustment and reconstruction can be classified into two modes of physical adjustment and variation of chemical compositions and five mechanisms. These mechanisms are occurrence displacement, biodegradat

关键词： Tarim Basin carbonate reservoirs oil and gas exploration of the Ordovician hydrocarbon accumulation mechanism hydrocarbon enrichment rule

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 Research Progress and status of In-situ Remediation Technology of Groundwater

引用

地学前缘 2009年第S1期16卷 34-35页

作者： Liuxin Jing,Guanji Zhao,Yancheng Dong school of Water resources & Environment,china {3. of geosciences(beijing),beijing 100083.china.

The characteristics and application of the in-situ remediation technology of groundwater,including air sparing,electro kinetic remediation,in-situ chemical oxidation,in-situ groundwater bioremediation and permeable re... 详细信息

关键词： groundwater remediation technology natural attenuation permeable reactive barriers

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

Ev surge Illuminates Pathto sustainable Mobility

引用

中印对话（英文版） 2024年第1期38卷 56-58页

作者： china-lndia Dialogue 不详

china's Booming NEVs zhang Yifan occupation:PhD student at the school of Philosophy,Renmin university of china Birth Place:Panzhihua,sichuan Current Residence:Lijiang,Yunnan Rapid advancements in technological innovation and energy transformation within the automotive industry in recent years have far exceeded *** market share of new energy vehicles(NEVs)in the automotive sector continues to grow,with globally recognized brands like Tesla and domestically acclaimed brands such as Xiaomi frequently capturing the public's attention.

关键词： sustainable occupation globally

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

Thermodynamic properties of LaCrO_3

引用

Rare Metals 2006年第5期25卷 562-566页

作者： CHEN Zhanheng XING Xianran YUAN Wenxia HUANG Xiaowei LI Hongwei school of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Office of the Chinese society of Rare earths Beijing 100081 China National Engineering Research Center for Rare earth Materials Beijing 100088 China

The nano powders of LaCrO3.were prepared by a sol-gel route. The heat capacity of LaCrO3.nano powders from 3.0 to 550 K was measured by DsC method and expressed as： Cpa2CrO3. （±0.112） = 166.844 - 8.500 ×10^-3.- 1.022×10^6T^-2 （J/（mol.K））（3.0-550 K）. An EMF measurement assembly was developed with CaF2 as an electrolyte for the galvanic cell. From measured EMF data of the reversible cell, （-） PL La2O3. LaF3. O2 （1 atm）lCaF2O2（1 atm）, LaF3. LaCrO3. Cr2O3. Pt（＋）, and the relevant value of Gibbs free energy, the Gibbs free energy of formation of LaCrO3.was calculated from 700 to 885 K： △G ФaLaCrO3.= -1555.3.4 ＋ 0.3.4T （kJ/mol）（700-885 K）. And the Gibbs free energy change of reaction from simple oxides La2O3.and Cr2O3.was calculated to be： AG f Oox（LaCrO3. = -94.758 ＋ 8.53.×10^-2T（kJ/mol）（700-885 K）.

关键词： lanthanum chromate Gibbs free energy of formation heat capacity EMF measurement nano powder

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 review of the New geophysics:a new understanding of pre-fracturing deformation in the crack-critical crust with implications for hydrocarbon production

引用

Petroleum science 2008年第1期5卷 1-12页

作者： stuart Crampin Yuan Gao school of geosciences University of Edinburgh UK Edinburgh Anisotropy Project British Geological Survey Edinburgh UK Institute of earthquake science China Earthquake Administration Beijing China

This paper reviews a new understanding of shear-wave splitting （seismic-birefringence） that is a fundamental revision of conventional fluid-rock deformation. It is a New geophysics with implications for almost all solid-earth geosciences, including hydrocarbon exploration and production, and earthquake forecasting. Widespread observations of shear-wave splitting show that deformation in in situ rocks is controlled by stress-aligned fluid-saturated grain-boundary cracks and preferentially orientated pores and pore-throats pervasive in almost all igneous, metamorphic, and sedimentary rocks in the earth＇s crust. These fluid-saturated microcracks are the most compliant elements of the rock-mass and control rock deformation. The degree of splitting shows that the microcracks in almost all rocks are so closely spaced that they verge on fracture-criticality and failure by fracturing, and are critical systems with the “butterfly wing＇s” sensitivity of all critical systems. As a result of this crack-criticality, evolution of fluid-saturated stress-aligned microcracked rock under changing conditions can be modelled with anisotropic poroelasticity （APE）. Consequently, low-level deformation can be： monitored with shear-wave splitting; future behaviour calculated with APE; future behaviour predicted with APE, if the change in conditions can be quantified; and in principle, future behaviour controlled by feed-back. This paper reviews our current understanding of the New geophysics of low-level pre-fracturing deformation.

关键词： Crack anisotropy New geophysics pre-fracturing deformation seismic birefringence,shear-wave splitting

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

Thermodynamic study on Process in Copper Converters (The Copper-making stage)

引用

International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 184-188页

作者： Chunlin Chen, Jiayun Zhang, Tuping Zhou, shoukun Wei, Xingxiang Lu2), Meng Bai, Jinhong Jiang ( Metallurgy school, university of science and Technology beijing,{3. Guixi smelter, Jiangxi, 3.5424) Metallurgy school University of Science and Technology Beijing Beijing 100083 China Guixi smelter Jiangxi 335424 China

Theoretical calculations were based on thermodynamic equilibrium in the multi-component and multi-phase system with heat and mass balance as well as the oxygen efficiency to take account for the effects of process kinetics. The variations of temperature, mass fractions of dissolved oxygen and sulfur in blister copper, partial pressures for O2, s2, sO2 in gas phase for the copper-making stage were calculated. The model predicted temperature, time of blowing as well as mass of the blister copper at end points for 6 heats showed a fairly good agreements with corresponding plant data. The calculated content of 0.065% and content of 0.87% in blister copper were both at reasonable levels. Compared with the so called Goto model, the present model has very much improved process description of copper-making stage as well as the prediction of end points for a copper converter by introducing the oxygen efficiency.

关键词： Peirce-smith copper converter thermodynamic model copper-making stage

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：