检索结果-南通市图书馆

Calculating soil moisture by remote sensing and analyzing hydrologic cycle process in the Yellow River basin

science china(Technological sciences) 2004年第Z1期47卷 1-13页

作者： YANG Shengtian1 & LIU Changming1, 2 1. School of Environmental sciences, beijing normal university, beijing 100875, china 2. Institute of Geographic science and Natural resources Research, beijing 100101, china School of Environmental sciences Beijing Normal University Beijing China Institute of Geographic science and Natural resources Research Beijing China

Based on the AVHRR pathfinder remote sensing data, soil moisture, precipitation and evaporation during the period of 1982—1998, soil moisture of all layers of soil-profile (0—1 m) in the Yellow River basin over the 17 years are calculated by the remote sensing model of calculating soil water. The Yellow River basin is divided into seven subcatchments as control sections at the location of six hydrologic stations (Lanzhou, Toudaoguai, Longmen, Sanmenxia, Huayuankou and Lijin). After calculating soil moisture and obtaining runoff data and precipitation data, the dynamical features of hydrological cycle in the Yellow River basin are analyzed for the period from 1982 to 1988 using water balance method. The conclusions are as follows: It is feasible to calculate the soil water on the macro-scale, in the soil profile with temporal continuity by means of remote sensing and survey in land. Some values of the key water cycle factors in the Yellow River are obtained, which include the annual precipitation of 4000 km3, the evapotranspiration of 3000-3500 km3, and the soil moisture transformation of ?500- 500 km3. Consequently, we analyzed the process of the water cycle in the Yellow River over the 17 years, and the results show that the segment upstream of Lanzhou city is a relatively humid region, and the area of internal waters and the reaches of Shanshan is the most desiccated region. Therefore, the runoff in the depth process is intensive and the runoff-generating process is weak in more arid regions.

关键词： the Yellow River, soil moisture, remote sensing, hydrologic cycle.

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

Threshold quantum secure direct communication without entanglement

引用

science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3 & WEN QiaoYan2 1 college of Computer science and technology, beijing university of technology, beijing 100022, china 2 School of science, beijing university of Posts and Telecommunications, beijing 100876, china 3 State Key Laboratory of Information Security (Graduate School of Chinese Academy of sciences), beijing 100049, china college of Computer science and technology Beijing University of Technology Beijing China State Key Laboratory of Information Security (Graduate School of Chinese Academy of sciences) Beijing China School of science Beijing University of Posts and Telecommunications Beijing China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

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

Sufficient and Necessary Conditions for Stochastic Comparability of Jump Processes

引用

Acta Mathematica Sinica,English Series 2000年第1期16卷 99-102页

作者： Yuhui Zhang Department of Mathematics,beijing normal university,beijing 100875,P.R.china Department of Mathematics Beijing Normal University Beijing 100875 P.R. China

This note is devoted to the study of the stochastic comparability of jump *** the basis of[2]and[3],it is proved that two jump processes are stochastically comparable if and only if their q-pairs are ***,the result co... 详细信息

关键词： Stochastically comparable Totally stable Conservative Uniqueness

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 Theory of Relativity on the Finsler Spacetime

引用

Journal of Systems Engineering and Electronics 1995年第4期6卷 239-252页

作者： Cao ShengLin (Department of Astronomy, beijing normal university, beijing 100875, china) Department of Astronomy Beijing Normal University Beijing 100875 China

According to some local properties of Lorentz transformation, Einstein stated: 'Vetheitiss greater than that of light have no possibility of existence.' He neglected to point out the applicable range of the special theory of relativity. In fact, it could only be applied to the subluminal-speeds. This paper shows that if ones think of the possibility of the existence of the superluminal-speeds and redescribe the special theory of relativity following Einstein's way, it could be supposed that the physical spacetime is a Finsler spacetime, characterized by the metric ds4=gijkldxidxidxkdxl. If so, a new spactime transformation could be found by invariant ds4 and the theory of relativity is discussed on this transformation it is possible that the Finsler spacetime F(x,y) may be endowed with a catastrophic nature. Based on the different properties between the ds2 and ds4, it is discussed that the flat spacetime will also have the catastrophic nature on the Finsler metric ds4. The spacetime transformations and the Physical quantities will suddenly change at the catastrophe set of the spacetime, the light cone. It will be supposed that only the dual velocity of the superluminal-speeds could be observed. If so, a particle with the superluminal-speed v> c could be regarded as its anti-particle with the dual velocity v1=c2/ v< c. On the other hand, it could be assumed that the horizon of the field of the general relativity is also a catastrophic set. If so, a particle with the superluminal-speeds could be projected near the horizon of these fields, and the particle will move on the sauce-like curves. It is very interesting that, in the Schwarzschild fields, the theoretical calculation for the sauce-like curves should be in agreement with tie data of the superluminal expansion of extragalactic radio sources observed year after year. (see Gao, 1992b).The ca- tastrophe of spacetime has some deep cosmological means. According to the some interested subjects in the Process of

关键词： Theory of relativity Finsler spacetime Superluminal-speed Subluminal-speed Catastrophe theory Superluminal expansion Extragalactic radio sources Cosmology

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 china’s Water Security and Virtual Water Trade

引用

Chinese Journal of Population,resources and Environment 2006年第4期4卷 18-23页

作者： Wang Hongrui1,2,Liu Xinghan3,Dong Yanyan1,2,Wang Junhong1,2 1.college of Water sciences,beijing normal university,beijing 100875,china 2.Key Laboratory for Water and Sediment sciences Ministry of Education,beijing 100875,china 3.college of Economics&Management,beijing university of technology,beijing 100022,china college of Water sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China college of Economics & Management Beijing University of Technology Beijing 100022 China College of Water Sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China college of Water sciences Beijing Normal University Beijing 100875 China Key Laboratory for Water and Sediment sciences Ministry of Education Beijing 100875 China

Producing goods and services all needs water *** water used in the process of an agricultural or industrial product is called the"Virtual Water"contained in this product. Through international trade,water-scarce countries and regions could purchase water-intensive products--especially foods,from water-rich countries to balance their water deficits and achieve water *** is one of the 13 most water-deficit countries whose water safety have been severely *** paper generalized the recent global research development and made a brief introduction about the methods calculating virtual water content in specific *** a case study,we qualified china's annual virtual water flows from year 2000 to 2002 with trade in crops,and ended with some policy advice for application and practice of virtual water strategy.

关键词： water security virtual water virtual water trade crops

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

Finite-dimensional (*)-serial algebras

引用

science china Mathematics 2010年第12期53卷 3049-3056页

作者： YAO HaiLou & FAN WeiLi college of Applied science, beijing university of technology, beijing 100124, china college of Applied science Beijing University of Technology Beijing China

Let A be a finite-dimensional associative algebra with identity over a field k. In this paper we introduce the concept of (*)-serial algebras which is a generalization of serial algebras. We investigate the properties of (*)-serial algebras, and we obtain suficient and necessary conditions for an associative algebra to be (*)-serial.

关键词： (*)-serial algebras biserial modules uniserial modules

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

Level Set interface treatment and its application in Euler method

引用

science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 227-236页

作者： WU KaiTeng1,2,HAO Li3,WANG Cheng4 & ZHANG Li1,2 1 Numerical Simulation Sichuan Higher School Key Laboratory,Neijiang normal university,Neijiang 641112,china 2 college of Mathematics and Information science,Neijiang normal university,Neijiang 641112,china 3.college of science,beijing university of Civil Engineering and Architecture,beijing 100044,china 4 State Key Laboratory of Explosion science and technology,beijing Institute of technology,beijing 100081,china Numerical Simulation Sichuan Higher School Key Laboratory Neijiang Normal University Neijiang China college of Mathematics and Information science Neijiang Normal University Neijiang China college of science Beijing University of Civil Engineering and Architecture Beijing China State Key Laboratory of Explosion science and technology Beijing Institute of Technology Beijing China

Level Set interface treatment method is introduced into Euler method,which is employed for interface treatment method for multi-materials. Combined with the ghost fluid method,the moving interface is tracked. Fifth-order WENO spatial discretization and third-order TVD Runge-Kutta time discretization methods are used. Shock-wave action on bubble,implosion and velocity field Shock effect bubbles; implosion and velocity field are simulated by means of LS-MMIC3D programmed by C++. Nu-merical results show that the Level Set interface treatment method is effective and feasible for multi-material interface treatment in comparison with the WENO method.

关键词： Euler method Level Set method shock-wave action on bubble implosion 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

Bursting of Morris-Lecar neuronal model with current-feedback control

引用

science china(Technological sciences) 2009年第3期52卷 771-781页

作者： DUAN LiXia1, LU QiShao2 & CHENG DaiZhan3 1 college of science, North china university of technology, beijing 100144, china 2 School of science, beijing university of Aeronautics and Astronautics, beijing 100191, china 3 Institute of Systems science, Chinese Academy of sciences, beijing 100190, china college of science North China University of Technology Beijing China School of science Beijing University of Aeronautics and Astronautics Beijing China Institute of Systems science Chinese Academy of Sciences Beijing China

The Morris-Lecar (ML) neuronal model with current-feedback control is considered as a typical fast-slow dynamical system to study the combined influences of the reversal potential VCa of Ca2+ and the feedback current I on the generation and transition of different bursting oscillations. Two-parameter bifurcation analysis of the fast subsystem is performed in the parameter (I, VCa)-plane at first. Three important codimension-2 bifurcation points and some codimension-1 bifurcation curves are obtained which enable one to determine the parameter regions for different types of bursting. Next, we further divide the control parameter (V0, VCa)-plane into five different bursting regions, namely, the "fold/fold" bursting region R1, the "fold/Hopf" bursting region R2, the "fold/homoclinic" bursting region R3, the "subHopf/homoclinic" bursting region R4 and the "subHopf/subHopf" bursting region R5, as well as a silence region R6. Codimension-1 and -2 bifurcations are responsible for explanation of transition mechanisms between different types of bursting. The results are instructive for further understanding the dynamical behavior and mechanisms of complex firing activities and information processing in biological nervous systems.

关键词： neuron bursting bifurcation fast-slow dynamics analysis codimension

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

Presenting degenerate Ringel-Hall algebras of type B

引用

science china Mathematics 2012年第5期55卷 949-960页

作者： FAN LiJuan1 & ZHAO ZhongHua2,1Department of Mathematics,beijing normal university,beijing 100875,china 2Department of Mathematics and Computer science,School of science,beijing university of Chemical technology,beijing 100029,china Department of Mathematics Beijing Normal University Beijing China Department of Mathematics and Computer science School of Science Beijing University of Chemical Technology Beijing China

We give a presentation for the degenerate Ringel-Hall algebras of type B by studying the corresponding generic extension monoid *** an application,it is shown that the degenerate Ringel-Hall algebras of type B admit m... 详细信息

关键词： degenerate Ringel-Hall algebras generic extension monoid algebras Auslander-Reiten quivers Frobenius morphism

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

Boundedness of Multilinear Operators in Herz-type Hardy Space

引用

Acta Mathematica Sinica,English Series 2000年第2期16卷 295-306页

作者： Lin Tang Dachun Yang Department of Mathematics,beijing normal university,beijing 100875,P.R.china Department of Mathematics Beijing Normal University Beijing 100875 P. R. China

Let k ∈ *** prove that the lnultilinear operators of finite sums of products of singular integrals on Rn are bounded from H Kqlαl·pl（Rn）×…×HKqkαk,pk（Rn）into HKqα,p（Rn）if they have vanishing moments up to a certain order dictated by the target *** conditions on vanishing moments satisfied by the multilinear operators are also necessary when αj（?）0 and the singular integrals considered here include the Calderón-Zygmund singular integrals and the fractional integrals of any orders.

关键词： Multilinear operator Calderón-Zygmund operator Fractional integral Multiplier Herz space Hardy space Atom

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：