检索结果-南通市图书馆

Numerical study of the auroral particle transport in the polar upper atmosphere

Science china(Technological Sciences) 2008年第10期51卷 1759-1771页

作者： CAI HongTao1,2, MA ShuYing1,2 & PU ZuYin3.1 School of Electronic Information, wuhan University, wuhan 43.079, china 2 {3. laboratory of geospace environment and geodesy, ministry of education of prc, wuhan 43.079, china 3.School of Earth and Space Sciences, Peking University, Beijing 100871, china School of Electronic Information Wuhan University Wuhan China key laboratory of geospace {3. and geodesy Ministry of Education of PRC Wuhan China School of Earth and Space Sciences Peking University Beijing China

Starting from the Boltzmann equation and with some reasonable assumptions, a one-dimensional transport equation of charged energetic particles is derived by taking account of major interactions with neutral species in the upper atmosphere, including the processes of elastic scattering, the excitation, the ionization and the secondary electron production. The transport equation is numerically solved, for a simplified atmosphere consisting only of nitrogen molecules (N2), to obtain the variations of incident electron fluxes as a function of altitude, energy and pitch angle. The model results can describe fairly the transport characteristics of pre-cipitating auroral electron spectra in the polar upper atmosphere; meanwhile the N2 ionization rates calculated from the modeled differential flux spectra also exhibit good agreements with existing empirical models in terms of several key parameters. Taking the energy flux spectra of precipitating electrons observed by FAST satellite flying over EISCAT site on May 15, 1997 as model inputs, the model-calculated ionization rate profile of neutral atmosphere consists reasonably with that recon-structed from electron density measurements by the radar.

关键词： aurora particle precipitation polar upper atmosphere electron transport equation numerical simulation

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

SATELLITE GRAVITY SURVEYING TECHNOLOGY AND RESEARCH OF EARTH’S GRAVITY FIELD

引用

大地测量与地球动力学 2003年第B12期23卷 1-7页

作者： Ning Jinsheng (The key laboratory of geo Space {3. and geodesy, ministry of education, wuhan University, wuhan 43.079, china) The key laboratory of geo-Space {3. and geodesy Ministry of EducationWuhan University Wuhan 430079 China

This is a summarized paper. Two topics are discussed: Firstly, the concept, development and application of four kinds of satellite gravity surveying technology are introduced; Secondly, some problems of theory and method, which must be considered in the study of the \{Earth’s\} gravity field based on satellite gravity data, are expounded.

关键词：卫星重力测量技术地球重力场卫星轨道技术概念技术进展技术应用空中重力测量

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

GRACE detection of the medium-to far-field coseismic gravity changes caused by the 2004 Mw9.3.Sumatra-Andaman earthquake

引用

Earthquake Science 2012年第3期25卷 235-240页

作者： Jin Li1,2,3.and Wenbin Shen1,3.4, 1 Department of geophysics, School of geodesy and geomatics, {3. University, wuhan 43.079, china 2 key laboratory of geodynamic geodesy of Chinese Academy, {3. 43.077, china 3.key laboratory of geospace environment and geodesy (ministry of education), {3. University, wuhan 43.079, china 4 State key laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, wuhan 43.079, china Department of geophysics School of Geodesy and Geomatics Wuhan University Wuhan China key laboratory of geodynamic {3. of Chinese Academy Wuhan China key laboratory of geospace {3. and geodesy (ministry of education) Wuhan University Wuhan China State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan China

Large earthquakes cause observable changes in the Earth’s gravity field, which have been detected by the Gravity Recovery and Climate Experiment (GRACE). Since most previous studies focus on the detection of near-field gravity effects, this study provides the results from the medium- to far-field gravity changes caused by the 2004 Sumatra-Andaman earthquake that are recorded within GRACE monthly solutions. Utilizing a spherical-earth dislocation model we documented that large-scale signals predominate in the global field of the coseismic gravity changes caused by the earthquake. After removing the near-field effects, the coseismic gravity changes show a negative anomaly feature with an average magnitude of -0.18×10-8 m·s-2 in the region ranging ～40° from the epicenter, which is considered as the 'medium ffield' in this study. From the GRACE data released by Center for Space Research from August 2002 to December 2008, we retrieved the large-scale gravity changes smoothed with 3.000 km Gaussian ffilter. The results show that the coseismic gravity changes detected by GRACE in the medium field have an average of (-0.20±0.06)×10-8 m·s-2, which agrees with the model prediction. The detection confirms that GRACE is sensitive to large-scale medium-field coseismic gravitational effects of mega earthquakes, and also validates the spherical-earth dislocation model in the medium field from the perspective of satellite gravimetry.

关键词： GRACE medium-to far-field coseismic gravity change 2004 Sumatra-Andaman earthquake spherical-Earth dislocation 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

A numerical study on nonlinear propagation and short-term variability of the migrating diurnal and semidiurnal tides

引用

Chinese Science Bulletin 2005年第17期50卷 1940-1948页

作者： HUANG Chunming1,2, ZHANG Shaodong1,2 & YI Fan1,2 1. School of Electronic Information, wuhan Universiy, wuhan 43.079, china 2. {3. laboratory of geospace environment and geodesy, ministry of education, wuhan University, wuhan 43.079, china School of Electronic Information Wuhan Universiy Wuhan China key laboratory of geospace {3. and geodesy Ministry of Education Wuhan University Wuhan China

By using a three-dimensional fully nonlinear numerical model in spherical coordinates and taking the linear steady solutions of the migrating diurnal and semidi-urnal tides in January from the Global-Scale Wave Model (GSWM) as the initial values, we simulate the linear and nonlinear propagations of the migrating diurnal and semidi-urnal tides in the atmosphere from the ground to the lower thermosphere. A comparison of our simulations with the results of GSWM is also presented. The simulation results show that affected by the nonlinearity, the migrating diurnal and semidiurnal tides propagating in the middle and upper atmosphere exhibit evident short-term variability. The nonlinear interactions between the migrating tides and the background atmosphere can obviously alter the background wind and temperature fields, which suggests that the nonlin-ear propagations of the migrating diurnal and semidiurnal tides impact significantly on the transient dynamical and thermal structures of the background middle and upper at-mosphere and the nonlinear effect is an important cause of the difference between the results of GSWM and observa-tions.

关键词：大气非线性传播数学模型可变性温度场

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

Global analysis on slope stability and its engineering application

引用

Science china(Technological Sciences) 2009年第2期52卷 507-512页

作者： ZHENG Hong1,2 & ZHOU ChuangBing3.1 State key laboratory of geomechanics and geotechnical Engineering, wuhan 43.071, china 2 china Three Gorges University, key laboratory of geological Hazards on Three Gorges Reservoir Area, ministry of education, Yi Chang 443.02, china 3.School of Civil Engineering, wuhan University, wuhan 43.072, china State key laboratory of geomechanics and geotechnical Engineering Wuhan China china Three Gorges University Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of Education Yi Chang China School of Civil Engineering Wuhan University Wuhan China

In hydraulic engineering, sometimes it is necessary to consider the stability of sliding bodies with lateral frictional boundaries. Neither the existing three dimensional limit equilibrium methods nor the commercial software products are able to treat such situations. The three dimensional factor of safety is accordingly underestimated; while the shearing strength based on the three dimensional back analysis is overestimated. In this study, the lateral boundaries are regarded as the part of the slip surface. Based on the expression of the normal pressure on the slip surface and the patch interpolation, a rigorous solution for the three dimensional limit equilibrium analysis is realized. Meanwhile, the proposed procedure is applied to the stability analysis of the slope with a cable platform on the right bank in Da Gang Shan hydraulic project under construction.

关键词： slope stability the limit equilibrium methods three dimensional problems

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

Atmospheric correction of HJ-1A/B CCD images over Chinese coastal waters using MODIS-Terra aerosol data

引用

Science china(Technological Sciences) 2010年第S1期53卷 191-195页

作者： TIAN LiQiao 1,LU JianZhong 1,CHEN XiaoLing 1,2,3.YU ZhiFeng 1,XIAO JingJing 1,QIU Feng 1 & ZHAO Xi 1 1 State key laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,wuhan University,wuhan 43.079,china 2key laboratory of Poyang Lake Wetland and Watershed Research,ministry of education,Jiangxi Normal University,Nanchang 3.0022,china 3.The key laboratory of Poyang Lake {13. and Resource Utilization,ministry of education,Nanchang University,Nanchang 3.003.,china State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan University Wuhan China key laboratory of Poyang Lake Wetland and Watershed Research Ministry of Education Jiangxi Normal University Nanchang China The key laboratory of Poyang Lake environment and Resource Utilization Ministry of Education Nanchang University Nanchang China

This paper demonstrates an atmospheric correction method to process HJ-1A/B CCD images over Chinese coastal waters with the aid of MODIS-Terra aerosol *** on the assumption of zero water-leaving radiance at the two near-infrared (NIR)bands or the shortwave infrared(SWIR)bands,the atmospheric aerosol optical depth(AOD)is firstly retrieved from MODIS-Terra with a simple extension of the NIR-SWIR combined atmospheric correction approach embedded in SeaDAS (SeaWiFS data analysis system).Then the"turbid"and"non-turbid"waters are separated by the turbid water *** probability of AOD at 551 nm band is derived based on the NIR information over"non-turbid"waters and FLAASH model is selected to do the atmospheric correction of the HJ-1A/B CCD imagery using the AOD values of highest probabilities as ***,according to the histogram of the AOD distribution at 551 nm band,the studied turbid water area is divided into several blocks and HJ-1A/B CCD imagery is corrected with the corresponding AOD values displayed with the highest frequency in each *** method has been applied to several HJ-1A/B images over Chinese coastal waters and validated by synchronous in-situ *** results have shown that this method is effective in the atmospheric correction process of HJ-1A/B CCD images for ocean color remote sensing study and application in the coastal waters.

关键词： ocean color remote sensing atmospheric correction turbid coastal waters HJ-1A/B MODIS

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

Petrogenesis of Songshugou dunite body in the Qinling orogenic belt, Central china: Constraints from geochemistry and melt inclusions

引用

Science china Earth Sciences 2005年第8期48卷 1146-1157页

作者： SU Li1,2, SONG Shuguang3.& ZHOU Dingwu1 1. key laboratory of Continental Dynamics of the ministry of {3., Department of geology, Northwestern University, Xi’an 710069, china 2. The geological Lab Center, china University of geosciences (Beijing), Beijing 100083. china 3. key laboratory of Orogenic Belts of the ministry of {3., Department of geology, Peking University, Beijing 100871, china key laboratory of Continental Dynamics of the ministry of {3. Department of Geology Northwestern University Xi’an China The geological Lab Center China University of Geosciences (Beijing)Beijing China key laboratory of Orogenic Belts of the ministry of {3. Department of Geology Peking University Beijing China

The Songshugou dunite body, which occupies an area of about 20 km2, is the largest ultramafic massif in the eastern Qinling orogenic belt, Central china. The major compo-nent of this body is dunitic rocks including mylonitic dunite and coarse-grained dunite; they oc-cupy about 95 vol% of the total body. Petrography, mineral composition, major and trace ele-ments and primitive melt inclusions have been investigated in this paper; all revealed that this dunite body is the product of melt-rock interaction by porous percolation flow. In comparison with dunite sills or veins in harzburgite from the basal part of Oman ophiolite, this dunite body is characterized by lower contents of Al2O3. CaO and HREE but higher content of highly incom-patible elements and Zr and Hf. The LREE enriched patterns and primitive mantle normalized spidergrams of trace elements are also different from the Oman dunite. Combining with melt in-clusions observed in olivines, we conclude that this dunite body is the product of large- scale porous percolation flow of high-MgO melts within depleted mantle peridotites. The high-MgO magma, in essence, was most probably produced at the hot head of an upwelling mantle plume. The occurrence of the Songshugou dunite body is closely associated with the activity of mantle super-plume in Neo-Proterozoic era in the Yangtze Craton.

关键词： Songshugou dunite body, geochemistry, melt inclusion, mantle plume, Qinling orogenic belt.

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

Node ordinal encoded genetic algorithm for the optimal allocation of water resources

引用

Progress in Natural Science:Materials International 2005年第5期15卷 448-452页

作者： YANG Xiaohua1*, YANG Zhifeng 1,2, SHEN Zhenyao1 and LI Jianqiang3.1. State key laboratory of Water environment Simulation, School of environment, Beijing Normal University, Beijing 100875, china 2. key laboratory for Water and Sediment Sciences ministry of education, School of environment, Beijing Normal University, Beijing 100875, china 3. Water Resources and Hydropower Planning and Design General Institute, MWR, Beijing 100011, china) State key Lab. of Water Environ. Simulation Sch. of Environ. Beijing Normal Univ. Beijing 100875 China key Lab. for Water and Sediment Sci. Min. of Edu. Sch. of Environ. Beijing Normal Univ. Beijing 100875 China Water Resources and Hydropower Planning and Design General Inst. MWR Beijing 100011 China

A new method, node ordinal encoded genetic algorithm (NOEGA), is proposed for solving water resources optimal allocation problems, in which the capacity of water resources is split into a number of smaller parts so that successive operations can be overlapped. Our objective is to maximize the whole benefit function. To overcome the “dimensionality and algorithm complexity curse” while searching for solutions and looking for an optimal solution, the operations of one-point crossover operator, gene exchange operator, gene random operator, gene shift operator and node ordinal strings are established. It is proved to be an effective optimal method in searching for global solutions. The NOEGA does not need a diversity of initial population, and it does not have the problem of immature convergence. The results of two cases show that using NOEGA to solve the optimal allocation model is very efficient and robust. In addition, the algorithm complexity of NOEGA is discussed.

关键词： water resources optimal allocation node ordinal code genetic algorithm.

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

MULTISCALE MECHANICAL BEHAVIORS IN DISCRETE MATERIALS: A REVIEW

引用

Acta Mechanica Solida Sinica 2010年第6期23卷 579-591页

作者： Xiaojing Zheng Dengming Wang (key laboratory of Mechanics on Western Disaster and environment,the {3. of education of china,Lanzhou University,Lanzhou 73.000,china) key laboratory of Mechanics on Western Disaster and environment the Ministry of Education of China Lanzhou University Lanzhou China

The discrete material, which belongs to the category of soft materials, is one of the most prevalent forms of matter in nature and engineering fields. These materials often exhibit abundant and complex mechanical properties which are still far from being perfectly understood. From the view of multi-scale framework concentrated on the ＇bridge＇ role in the macro-micro relation, this review mainly introduces some theoretical investigations of mechanical behaviors in discrete materials, including the continuum constitutive model based on the macroscopic phenomenological approach and coupled micro-macro approach, the statistical analysis of some microscopic physical quantities involved contacted forces between particles and its transmission within the whole system, and the statistical analysis for some microscopic processes in aeolian landform systems involving the grain-bed impact, the transportation and sedimentation of wind-blown sand flux, et al. Finally, some further worthwhile challenges in these fields are suggested.

关键词： discrete material multiple space and time scales trans-scales correlation sanddune statistical analysis

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

Transport network and flow mechanism of shallow ore-bearing magma in Tongling ore cluster area

引用

Science china Earth Sciences 2006年第4期49卷 397-407页

作者： DENG Jun1,2, WANG Qingfei1,2 , HUANG Dinghua3., WAN Li4, YANG Liqiang1,2 & GAO Bangfei1,2 1. State key laboratory of geological Processes and Mineral Resources,{3. University of geosciences, Beijing 100083.{3. 2. key laboratory of Lithosphere Tectonics and Lithoprobing Technology of ministry of education,{3. University of geo- sciences, Beijing 100083.{3. 3. Faculty of Earth Sciences,{3. University of geosciences, wuhan 43.074,{3. 4. School of Mathematics and Information Science, Guangzhou University, Guangzhou 510405,{3. State key laboratory of geological Processes and Mineral Resources China University of Geosciences Beijing China key laboratory of Lithosphere Tectonics and Lithoprobing Technology of ministry of {3. China University of Geosciences Beijing China Faculty of Earth Sciences China University of Geosciences Wuhan China School of Mathematics and Information Science Guangzhou University Guangzhou China

Abundant studies revealed that shallow intrusions of the Yanshanian epoch resulted in the mass mineralization of the Tongling region. Various evidences showed there existed a concealed magma chamber at ?10 km depth in the middle part of this region during Yanshanian epoch, from which the ore-forming magma was generated and then transported to the superficial layer. Yet the transport network and flow mechanism of the shallow ore-bearing magma, the key problem associ- ated with ore-forming process, was relatively little focused on. Integrate analysis of structural me- chanics, statistical fractal and geological facts suggested that NE trending high-angle fold-related thrust faults and the tessellated basement ones served as the main pathways for the shallow magma’s transporting, moreover, the saddle void spaces among adjacent strata in the folds upon this fault system provided the place for magma’s emplacement. So the folds in the upper part and faults in the lower part of the upper crust constituted the fluid’s transport and emplacement network. During the deformation of geologic body with multi-layer structure, the layers in the upper part tended to fold when received the jacking stress from the lower part, while the lower one inclined to fault undergoing loads of the upper part. And the producing probability of this structure assemblage was highly in- creased in the condition, such as in the Tongling area, that the mechanic rigidity of the lower layers was stronger than that of the upper ones. For the pre-existence of fluid-conducting network, the top magma with high volatile in the magma chamber transported rapidly to the superficial layer in dyking pattern, located in the void spaces of folds, filled and reconstructed them. The sudden drop of pres- sure caused the fluid unmixing from the magma and mass ore-forming elements concentration. Pulse activity of the dyking may be the principal reason why magmatic bodies in the Tongling area were spatially-temporally con

关键词： Tongling, structural network, magma intrusion, fractal, dyke.

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：