检索结果-南通市图书馆

Monitoring the Cultivated Slope Land in the Three Gorges Reservoir Area Based on Remote Sensing and GIS

Wuhan university Journal of Natural sciences 2006年第4期11卷 915-921页

作者： ZHOU Jieming1, ZHOU Qigang 2, 3 ,HUANG Zhiqin 2, 3, 4 1. The Faculty of Geography and Resources science, sichuan normal university, chengdu 610066, sichuan, china 2. institute of Mountain Hazards and Environment, Chinese Academy of sciences, chengdu 610041, sichuan, china 3. Graduate university of the Chinese Academy of sciences, Beijing 100049, china 4. Information Center of Land and Resources Department of sichuan Province, chengdu 610041, sichuan, china The Faculty of Geography and Resources science Sichuan Normal University Chengdu Sichuan China institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate university of the Chinese Academy of sciences Beijing China Information Center of Land and Resources Department of sichuan Province Chengdu Sichuan China

By means of combining auto-extraction with manual interpretation, the current distribution information about cultivated land is obtained. The distribution information of 1992 is extracted from the dynamic polygons of 2002. The monitoring mini-system of the cultivated slope land is established. In the system, detailed surveys, focused on the resources of cultivated slope land, are carried out. The results indicate that the area of the cultivated slope land is very large. Meanwhile, there are lots of cultivated steep slopes with gradient above 35°. The areas of steep land cultivated had been slowly reduced from 1992 to 2002. At the same time, the pressures of returning farm land to forestry are great in all counties. The conflicts between population growth, insufficient grain supply and stagnant economic development sharpen increasingly. It is inevitable to improve the agricultural structure.

关键词： slope land cultivated remote sensing geography information system (GIS) the pressure of returning farm land to forestry Three Gorges Reservoir Area

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

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of N_(2)molecule

引用

science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 385-398页

作者： REN Weiyi1,2, SUN Weiguo1, HOU Shilin3 & FENG Hao4 1. institute of Physics, College of Chemical Engineering, sichuan university, chengdu 610065, china 2. institute of Theoretical Physics, Xihua normal university, Nanchong 637002, china 3. Department of Physics, china Oceanography university, Qingdao 266003, china 4. College of Physics, sichuan university, chengdu 610065, china institute of Physics College of Chemical Engineering Sichuan University Chengdu China institute of Theoretical Physics Xihua Normal University Nanchong China Department of Physics China Oceanography University Qingdao China College of Physics Sichuan University Chengdu China

It is usually very difficult to directly obtain molecular dissociation energy De and all accurate high-lying vibrational energies for most diatomic electronic states using modern experimental techniques or quantum theories, and it is also very difficult to give accurate analytical expression for diatomic molecular dissociation energy. This study proposes a new analytical formula for obtaining accurate molecular dissociation energy based on the LeRoy and Bernstein’s energy expression in dissociation limit. A set of full vibrational energy spectra for some electronic states of N2 molecule are studied using the algebraic method (AM) suggested recently, and the corresponding accurate molecular dissociation energies are evaluated using the proposed new formula and high-lying AM vibrational energies. The results show that the AM spectra and the new theoretical dissociation energies agree excellently with experimental data, and thereby providing a new physical approach to generating accurate dissociation energies for electronic states of diatomic molecules.

关键词： vibrational energy, dissociation energy, nitrogen molecule, algebraic method.

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

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

引用

science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2 & TIAN Anmin2 1. Department of Chemistry, Southwest-china normal university, Chongqing 400715, china 2. Department of Chemistry, sichuan university, chengdu 610064, china Department of Chemistry Southwest-China Normal University Chongqing China Department of Chemistry Sichuan University Chengdu China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

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

LOW ORDER NONCONFORMING RECTANGULAR FINITE ELEMENT METHODS FOR DARCY-STOKES PROBLEMS

引用

Journal of Computational mathematics 2009年第Z1期 400-424页

作者： Shiquan Zhang School of mathematics,sichuan university,chengdu 610064,china Xiaoping Xie Yangtze Center of mathematics and School of mathematics,sichuan university,chengdu 610064,china Yumei Chen School of mathematics,sichuan university,chengdu 610064,china College of mathematics and Information,china West normal university,Nanchong 637002,china

In this paper,we consider lower order rectangular finite element methods for the sin-gularly perturbed Stokes *** model problem reduces to a linear Stokes problemwhen the perturbation parameter is large and degenerates to a mixed formulation of Pois-son’s equation as the perturbation parameter tends to *** propose two 2D andtwo 3D nonconforming rectangular finite elements,and derive robust discretization *** experiments are carried out to verify the theoretical results.

关键词： Darcy-Stokes problem Finite element Uniformly stable

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

A study of the optimal solution of a macroeconomics model

引用

西南师范大学学报(自然科学版) 1999年第5期24卷 519-525页

作者： Xiong Dasheng 1,Du Dongyao 2 1 Department of mathematics,Southwest china normal university,Chongqing 400715 2 Financial Section,sichuan Union university,chengdu 610065 西南师范大学数学系重庆四川大学financial section 重庆

The optimal economic growth is always a main problem in economic control theory and it has been investigated by many scholars in their papers. A new sufficient condition of optimal control from a new angle is put forw... 详细信息

关键词： optimal economic growth optimal control sufficient condition trajectory

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

Efficient video cutout based on adaptive multilevel banded method

引用

science china(Information sciences) 2012年第5期55卷 1082-1092页

作者： CHEN MinGang 1,SUI BoCong 1,GAO Yan 2 & MA LiZhuang 1 1 Department of Computer science and Engineering,Shanghai Jiao Tong university,Shanghai 200240,china 2 software Engineering institute,East china normal university,Shanghai 200062,china Department of Computer science and Engineering Shanghai Jiao Tong University Shanghai China software Engineering institute East China Normal University Shanghai China

Although many efficient image cutout approaches have been proposed,it is still a challenge to cut out foreground objects from a video clip because of the costs of time and memory consumption and the difficulty in maintaining temporal coherence for the cutout *** this paper,we propose a novel and efficient video cutout approach by extending a multilevel banded image segmentation method to video *** our method,the segmentation results are propagated frame by frame at the lowest resolution level based on optical flow,and are refined in image pyramids level by level through banded graph *** construct an adaptive narrow band to ensure that the segmentation result falls exactly into the narrow band during *** results show that the video cutout approach based on adaptive multilevel bands dramatically reduces time and memory costs,and achieves ideal segmentation results.

关键词： video object cutout multilevel band graph cuts video segmentation

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

A New Process and Framework for Direct Anonymous Attestation Based on Symmetric Bilinear Maps

引用

Wuhan university Journal of Natural sciences 2011年第5期16卷 369-375页

作者： TAN Liang1,2, ZHOU Mingtian3 1. College of Computer/Key Lab of Visualization in Scientific Computing and Virtual Reality of sichuan, sichuan normal university, chengdu 610066, sichuan, china 2. institute of Computing Technology, Chinese Academy of sciences, Beijing 100190, china 3. School of Computer science and Engineering, university of Electronic science and Technology of china, chengdu 610054, sichuan, china College of Computer/Key Lab of Visualization in Scientific Computing and Virtual Reality of sichuan Sichuan Normal University Chengdu Sichuan China institute of Computing Technology Chinese Academy of Sciences Beijing China School of Computer science and Engineering University of Electronic Science and Technology of China Chengdu Sichuan China

For the problem of the original direct anonymous attestation （DAA） scheme＇s complexity and great time consumption, a new DAA scheme based on symmetric bilinear pairings is presented, which gives a practical solution to ECC-based TPM in protecting the privacy of the TPM. The scheme still includes five procedures or algorithms： Setup, Join, Sign, Verify and Rogue tagging, but gets rid of zero-knowledge proof and takes on a new process and framework, of which the main operations are addition, scalar multiplication and bilinear maps on supersingular elliptic curve systems. Moreover, the scheme adequately utilizes the properties of bilinear maps as well as the signature and verification of the ecliptic curve system itself. Compared with other schemes, the new DAA scheme not only satis- fies the same properties, and shows better simplicity and high effi- ciency. This paper gives not only a detailed security proof of the proposed scheme, but also a careful performance analysis by comparing with the existing DAA schemes.

关键词： direct anonymous attestation bilinear map privacy authentication trusted computing platform trusted platform module

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

An improved approach to the efficient construction of and search operations in motion graphs

引用

science china(Information sciences) 2012年第5期55卷 1042-1051页

作者： GAO Yan 1,CHEN ZhiHua 2,CHEN MinGang 3 & SHEN Yang 3 1 software Engineering institute,East china normal university,Shanghai 200062,china 2 Department of Computer science and Engineering,East china university of science and Technology,Shanghai 200237,china 3 Department of Computer science and Engineering,Shanghai Jiao Tong university,Shanghai 200240,china software Engineering institute East China Normal University Shanghai China Department of Computer science and Engineering East China University of Science and Technology Shanghai China Department of Computer science and Engineering Shanghai Jiao Tong University Shanghai China

Motion graphs have been widely used as an effective technique in the synthesis of human *** synthesize well-formed motions,motion graphs require smooth transitions and good ***,the time and costs grow quadratically as the graph size *** this paper,we present a method to set up a hierarchical structure,called a structure *** coarse level of this graph models different motion categories and their transitions,and the fine level mainly captures different motion *** interpolation space method is used to improve the graph connectivity at the fine *** structure guides the establishment of a faster and more realistic graphical *** the building process,this structure also helps with searching the motion graph,by performing a traverse search and placing the findings into a direct look-up table or local search ***,when there is no direct link between the different motions,a navigation map is introduced to conduct an appropriate search path via a series of transition motion *** experimental results indicate that our approach could lower the computation time in construction and searching,while simultaneously providing a richer variety of motion styles.

关键词： motion graph structure table registration curve motion interpolation

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

ON F-z-SUPPLEMENTED SUBGROUPS OF FINITE GROUPS

引用

Acta Mathematica Scientia 2011年第1期31卷 22-28页

作者：郭文彬唐娜李保军 Department of mathematics University of Science and Technology of China Department of mathematics Xuzhou Normal University Department of mathematics Huaiyin Teachers College School of mathematics Chengdu University of Information Technology

A subgroup H of a group G is called F-z-supplemented in G if there exists a subgroup K of G, such that G = HK and H∩K≤ Z∞F（G）, where Z∞F（G） is the F-hypercenter of G. We obtain some results about the F-z-suppl... 详细信息

关键词： Finite groups local formations F-z-supplemented subgroups supersoluble groups p-nilpotent groups

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

Analysis of forest backscattering characteristics based on polarization coherence tomography

引用

science china(Technological sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2,CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 21 institute of Geo-Spatial Information science and Technology,university of Electronic science and Technology of china,chengdu 610054,china 2 State Key Laboratory of Remote Sensing science,Jointly Sponsored by the institute of Remote Sensing Applications of Chinese Academy of sciences and Beijing normal university,Beijing 100101,china 3institute of Forest Resources Information Technique of Chinese Academy of Forestry,Beijing 100091,china 4 School of Electronic Engineering,university of Electronic science and Technology of china,chengdu 610054,china institute of Geo-Spatial Information science and Technology University of Electronic Science and Technology of China Chengdu China State Key Laboratory of Remote Sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China institute of Forest Resources Information Technique of Chinese Academy of Forestry Beijing China School of Electronic Engineering University of Electronic Science and Technology of China Chengdu China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

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：