检索结果-南通市图书馆

TRANSPORTATION INEQUALITIES FOR WEAKLY DEPENDENT SEQUENCES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2011年第4期31卷 1494-1502页

作者：马宇韬 School of Mathematical sciences Beijing Normal University

In [3], they gave necessary and sufficient condition for T 1 C and then as applications T 1 C for weakly dependent sequences was established. In this note, based on Gozlan-L′eonard characterization for W 1 H -inequal... 详细信息

关键词： W 1 H inequality T p (C)-inequality weakly dependent sequences tensorization

Linear operators preserving the generalized decomposable numerical range

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第1期42卷 22-26页

作者： LEI TiangangDepartment of Mathematics, beijing normal university, beijing 100875,{2. Department of Mathematics Beijing Normal University Beijing 100875 China

LET G be a subgroup of the symmetric group Sm. Denote by CG the set of all functions f: G→C. A function f∈CG is said to be positive semi-definite （p. s. d. ） if there exists c∈CG such that for all τ∈G. In particular, the irreducible complex characters of G are p. s. d. Let Cn×m denote the set of all n×m complex matrices. For f∈CG, the

关键词： decomposable numerical range linear operator positive semi-definite function generalized matrix function.

Solvation effects on brain uptakes of isomers of ^(99m)Tc brain imaging agents

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第21期47卷 1786-1791页

作者： JIA Hongmei, MA Xiaohui, WANG Cunxin & LIU Boli1. Department of Chemistry, beijing normal university, beijing 100875,{2. 2. Center for Biomedical Engineering, beijing Polytechnic university, beijing 10002.,{2. 1. Department of Chemistry Beijing Normal University Beijing 100875 China 2. Center for Biomedical Engineering Beijing Polytechnic University Beijing 100022 China

Analysis of electrostatic hydration free energies of the isomers of the 99mTc-BAT and 99mTc-DADT complexes is carried out using the computer simulation technique. The results show that not only a correlation exists between the logarithm of the brain uptake and the electrostatic hydration free energy for the isomers of 99mTc-brain radiopharmaceu-ticals, but also a linear relationship exists between the logarithm of the ratio of the brain uptake of the syn isomer to that of the anti one and the difference between the electrostatic hydration free energy of the syn-isomer and that of the anti one. Furthermore, the investigation on the important factors influencing the brain uptakes of 99mTc-radiophar-maceuticals and the reasons of the different biodistribution of the isomers of the 99mTc-complexes is explored at the molecular level. The results may provide a reference for the rational drug design of brain imaging agents.

关键词： 99mTc-brain imaging agent isomer brain uptake electro-static hydration free energy.

Estimation methods of eco-environmental water requirements: Case study

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2005年第8期48卷 1280-1292页

作者： YANG Zhifeng1,2. CUI Baoshan1 & LIU Jingling 1. School of Environment, beijing normal university, beijing 100875,{2. 2. State Key Joint Laboratory of Environmental Simulation and Pollution Control, beijing 100875,{2. 1. School of Environment Beijing Normal University 100875 Beijing China 2. State Key Joint Laboratory of Environmental Simulation and Pollution Control 100875 Beijing China

Supplying water to the ecological environment with certain quantity and quality is significant for the protection of diversity and the realization of sustainable development. The conception and connotation of eco-environmental water requirements, including the definition of the conception, the composition and characteristics of eco-environmental water requirements, are evaluated in this paper. The classification and estimation methods of eco-environmental water requirements are then proposed. On the basis of the study on the Huang-Huai-Hai Area, the present water use, the minimum and suitable water requirement are estimated and the cor-responding water shortage is also calculated. According to the interrelated programs, the eco-environmental water requirements in the coming years (2.10, 2.30, 2.50) are estimated. The result indicates that the minimum and suitable eco-environmental water requirements fluc-tuate with the differences of function setting and the referential standard of water resources, and so as the water shortage. Moreover, the study indicates that the minimum eco-environmental water requirement of the study area ranges from 2.84×1010m3 to 1.02.1011m3, the suitable water requirement ranges from 6.45×1010m3 to 1.78×1011m3, the water shortage ranges from 9.1×109m3 to 2.16×1010m3 under the minimum water requirement, and it is from 3.07×1010m3 to 7.53×1010m3 under the suitable water requirement. According to the different values of the water shortage, the water priority can be allocated. The ranges of the eco-environmental water re-quirements in the three coming years (2.10, 2.30, 2.50) are 4.49×1010m3?1.73×1011m3, 5.99×10m3?2.09×1011m3, and 7.44×1010m3?2.52.1011m3, respectively.

关键词： eco-environmental water requirements, assessment methods, Huang-Huai-Hai area.

EXISTENCE AND ASYMPTOTIC BEHAVIOR OF THE SOLUTIONS FOR A NONLINEAR ELLIPTIC EQUATION ARISING IN ASTROPHYSICS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2006年第2期26卷 229-245页

作者：唐仲伟 School of Mathematical sciences beijing normal university Beijing 100875China

The author first analyzes the existence of ground state solutions and cylindrically symmetric solutions and then the asymptotic behavior of the ground state solution of the equation -△u =φ（r）u^p-1, u 〉 0 in R^N, u ∈ D^1,2.R^N）, where N ≥ 3, x = （x^1,z） ∈ R^K×R^N-K,2.≤ K ≤ N,r = ｜x′｜. It is proved that for 2.N-s）/（N-2. 〈 p 〈 2.＊ = 2./（N - 2., 0 〈 s 〈 2. the above equation has a ground state solution and a cylindrically symmetric solution. For p = 2.＊, the above equation does not have a ground state solution but a cylindrically ***, and when p close to 2.＊, the ground state solutions are not cylindrically symmetric. On the other hand, it is proved that as p close to 2., the ground state solution Up has a unique maximum point xp = （x′p, Zp） and as p → 2.＊, ｜x′p｜ → r0 which attains the maximum of φ on R^N. The asymptotic behavior of ground state solution Up is also given, which also deduces that the ground state solution is not cylindrically symmetric as p goes to 2.＊.

关键词： Cylindrical symmetry asymptotic behavior ground state solution

The Principal Eigenvalue for Jump Processes

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2000年第3期16卷 361-368页

作者： Mufa Chen Department of Mathematics,beijing normal {2.,beijing 100875,P.R.china Department of Mathematics Beijing Normal University Beijing 100875 P. R. China

A variational formula for the lower bound of the principal eigenvalue of general Markov jump processes is *** result is complete in the sense that the condition is fulfilled and the resulting bound is sharp for Markov... 详细信息

关键词： Principal eigenvalue Jump processes Variational formula for Dirichlet form

Redevelopment of liftoff rates of saltating sand grains based on a simple optimization model

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第4期53卷 568-574页

作者： CHENG Hong & ZOU XueYong State Key Laboratory of Earth Surface Processes and Resource Ecology,beijing normal {2.,beijing 100875,china MOE Engineering Center of Desertification and Blown-sand Control,beijing normal {2.,beijing 100875,china Key Laboratory of Environmental Change and Natural Disaster of the Ministry of Education of{12.,beijing normal {2.,beijing 100875,china 1. State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Beijing 100875 China2. MOE Engineering Center of Desertification and Blown-sand Control Beijing Normal University Beijing 100875 China3. Key Laboratory of Environmental Change and Natural Disaster of the Ministry of Education of China Beijing Normal University Beijing 100875 China

This paper is a redevelopment result of liftoff rates of saltating sand grains based on our previous *** sand flow is a complex multi-phase flow because of a special two-phase gas-solid flow near ground *** extensive research on the movement of blowing sand,no model fully characterizes aeolian sand flow,and large differences often exist between simulations of aeolian sand movement and field *** key problem is a few of sufficient research on liftoff rates of saltating sand grains(also called the number of liftoff sand grains per unit time and per unit bed area).It is necessary to re-search in advance liftoff rates of saltating sand *** redeveloped liftoff rates of saltating sand grains by establishing an optimization model based on the flux of aeolian sand flow at different heights of the sampler in wind tunnel and the simulated capture of saltating sand grains by different heights of the sampler that are from different liftoff position(distance from the sampler) in order to revise previous inversion condition of liftoff rates of saltating sand *** rates increased rapidly with increasing wind *** frictional wind velocities of u=0.67,0.77,0.82.0.83,and 0.87 m s-1,liftoff rates were 3840,954502.52.5114,5499407,and 76962.1 sand grain s-1 m-2.*** rates could be expressed as the square of the instantaneous frictional wind velocity and a constant(0.663) that differs from the critical(threshold) frictional wind velocity at which saltation *** our results require additional experimental validation and the simple optimization model must be improved,they nonetheless provide a strong basis for future research.

关键词： liftoff rates of saltating sand grains optimization model wind tunnel two-phase gas-solid flow

Entropy number and non-linear approximations on multivariate Besov space by manifolds of finite pseudo-dimension

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第3期16卷 260-265页

作者： LONG Jingfan and FANG Gensun (School of Mathematical sciences, beijing normal university,{2., china Department of Computer Science, Information Technology Institute, beijing 100101, china) [a]School of Mathematical sciences Beijing Normal University Beijing China [b]Department of Computer Science Information Technology Institute Beijing China

We determine the asymptotic order of entropy number and optimal non -linear approximations of anisotropic periodic Besov class of Bpθr(Td') (1≤p≤∞,1≤0≤∞) by manifolds of finite pseudo-dimension in the metric Lq... 详细信息

关键词： Pseudo-dimension anisotropic Besov class of functions entropy number nonlinear width.

Birth-death processes on trees

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2010年第11期53卷 2993-3004页

作者： MA YuTao School of Mathematical sciences & Laboratory of Mathematics and Complex Systems, beijing normal university,{2., china 1. School of Mathematical sciences & Laboratory of Mathematics and Complex Systems Beijing Normal University Beijing 100875 China

In this paper, we consider birth-death processes on a tree T and we are interested when it is regular, recurrent and ergodic (strongly, exponentially). By constructing two corresponding birth death processes on Z+, we obtain computable conditions sufficient or necessary for that (in many cases, these two conditions coincide). With the help of these constructions, we give explicit upper and lower bounds for the Dirichlet eigenvalue λ0. At last, some examples are investigated to justify our results.

关键词： birth-death process tree ergodicity Dirichlet eigenvalue