一类含非局部源和非变分形式的椭圆型方程组正解的存在性

本文研究一类含非局部源的椭圆型方程组{-A(∫Ω|u|kdc)△pu=λvm∫Ωuαvβdx,x∈Ω -B(∫Ω|v|sdx)△qv=μun∫Ωuγvδdx,x∈Ω (0.1)并且带有Dirichlet零边界条件的正解存在性.这里Ω是RN,N≥1中的有界区域,边界( 6)Ω光滑.为了得到它的解,我们先考虑与之相应的局部椭圆型方程组-△pu=λvm,-△qv=μuninΩ;u=v=0,on (6)Ω (2)正解的存在性.我们将应用上下解方法得到问题(1)和(2)的解.     

一类流行病数学模型解的研究

该文讨论了如下一类非线性抛物线方程组解的性质｛(e)u/(e)t=d1△u-a11u+∫Ωk(ξ)v(ξ,t)dξ (e)v/(e)t=d2△v-a22v+um (x,t)∈Ω×(0,∞) u(x,0)=u0(x) v(x,0)=v0(x) x∈Ω (1) B[u]=a(x)(e)u/(e)n+β(x)u=0 B[v]=a(x)(e)v/(e)n+β(x)v=0 x∈(e)Ω 利用微分方程上、下解方法证明了初值适当小时,方程存在整体解;初值适当大时,解在有限时间上爆破,推广了文献[1]的结果.     

具非局部源退化抛物方程组解全局存在和爆破

本文讨论了下列非局部退化抛物方程组ut=uT(△u ∫Ω f(v)dx),vt=(△v ∫Ωg(v)dx),(x,t)∈Ω×(0,∞)的爆破性质.在一定条件下,方程组解在有限时刻爆破且爆破点集是整个区域.     

一类哈密顿型椭圆方程组解的存在性与多重性

考虑哈密顿型椭圆方程组{-△u+V(x)u=Hv(x,u,v) x∈RN -△v+V(x)v=Hu(x,u,v) x∈RN u(x)→0,v(x)→0 | x |→∞其中z=(u,v):RN→R×R,N≥3.假设位势V是非周期的,0(∈)σ(-△+V);H(x,z)关于x是非周期的,关于z=(u,v)是渐近二次的.利用变分方法讨论了解的存在性与多重性.     

Darboux变换求一个新的孤子方程的精确解

以平凡解u=0,v=1作为种子解,代入矩阵谱问题Φx=UΦ,U=(-λ+u v～(1/2) v λ-u),Φt=VΦ,V=(V1 V2 V3 -V1),其中V1=-λ2+u2+1/6ux+1/6(lnv)xx+1/8(lnv)x2,V2=vλ+uv-1/2vx,V3=(vλ)～(1/2)+uv～(1/2)+vx/(4v～(1/2)).求出基本解.选取两个基本解φ(λj)=(coshξjβjsinhξj+λj coshξj),ф(λj)=(sinhξjβjcoshξj+λj sinhξj),其中ξj=βj(x+λj t),βj=(λj2+1)～(1/2),(1≤j≤N-1).再利用克莱姆法则和达布变换求出方程的非平凡解,最后又具体给出N=1和N=2两种情形.     

边色数的点与边临界性质

关于边色数的点与边临界我们得到如下结论: 定理1 设图G是边色数边临界的。d(v)=2。N(v)={u,w}。且(u,w)∈E(G)。令G′=G·v,若x是G′中分离u,w之割点,则必存在y∈V(G′),使得(x,y)∈E(G′)且d(x)=d(y)=△(G)。定理2 若图G是边色数边临界的,且边集{e,f}为G的二边割,又设e=(x,y),f=(u,w)则二边割e,f边分别关联G的最大次顶点。     

含多奇性临界双调和椭圆型问题解的存在性

文章主要在有界域Ω中研究了如下含多奇性的半线形椭圆型问题{△2u=k∑i=1λiu/|x-ai|4 u2*-1,x∈Ω u=(б)u/(б)v=0,x∈(б)Ω u＞0,x∈Ω\{a1,…,an}其中N≥5,k∈N,(λ1,λ2,…,λk)∈Rk,(a1,a2,…,ak)∈RkN且2*=2N(-)N-4是临界的嵌入指数,由于Sobolev嵌入失去紧性,所以文章将通过集中紧原理得到正解的存在性.     

含临界指数的双调和问题非平凡解的存在性

讨论如下含临界指数的双调和方程非平凡解的存在性{Δ2u=μ(u)/(|x|s) |u|2*-2u λu f(x), x∈Ω,u=((e)u)/((e)v)=0, x∈(e)Ω .其中Ω(∪)RN是有界光滑区域,0∈Ω, N≥5, 0≤s≤4,0≤μ＜(-μ)=(N(N-4)/4)2,2*=(2N)/(N-4)为W2,2(Ω)中Sobolev嵌入的临界指数,u, v表示(e)Ω的外法线方向,f(x)为给定函数.通过变分方法,我们证明了含临界指数的双调和方程非平凡解的存在性.     

人口问题中的三维Ginzburg-Landau模型方程

讨论以下三维广义Ginzburg—Landau方程的初边值问题{u1=-a1↓△^4u a2↓△^24 ↓△^2g(u) g(u),u|DΩ=0,↓△^2u|DΩ=0,u(x,0)=u0(x)。首先，应用Galerkin方法和紧致性定理证明上述问题整体广义解和整体古典解的存在性和惟一性；其次，给出了解爆破的充分条件；最后，证明上述问题的广义解和古典解当t→ ∞时依L2范数趋于零。     

一类耦合型薛定谔系统径向正解的存在性

利用变分法和椭圆方程理论研究如下的非线性薛定谔方程组:{-Δu+u=h(u)+λ2uv~2/(1+u~2v~2),x∈R~N,-Δv+v=g(v)+λ2u~2v/(1+u~2v~2),x∈R~N,u→0,v→0,x→+∞.假设h和g满足一定的条件,■λ_0∈(0,1),λ∈(0,λ_0),得到径向正解的存在性.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。