含弱阻尼和源项的非线性波方程的初边值问题

研究了含弱阻尼和源项的非线性波方程初边值问题．利用势阱理论和凹方法，证明当初始能量E（0）满足0〈E（O）〈d时（其中d为势阱深度）整体解的不存在性．     

一类非线性波动方程的整体解和爆破解

文章关注一类带有阻尼与源项的非线性波动方程在初始能量E(0)小于一个定值d的前提下,整体解的存在问题。当方程的初始数据‖▽u~0‖_2~2小于一个常数λ_0时,利用势阱理论获得方程整体解的存在性,并且借助于积分不等式,得到该方程解的指数衰减性质。当该方程的阻尼项g(u~′)消失且初始数据‖▽u~0‖_2~2大于常数λ_0时,利用凸的方法获得方程的爆破解。     

离子注入射程分布的Brice方程的数学推导

Brice在1970—1975年给出离子注入射程分布所满足的方程: 其中,P(E,E′,R)是初始能量为E的离子当其能量下降为E′(0≤E′相似文献   

高阶拟线性橢圆方程的非橢边值间题

关于线性椭圆方程的非椭边值问题已有不少作者进行了大量的研究,H?rmander研究了一阶方程组的非椭边值问题。(非正则边值问题,亦即边值条件不满足Lopatinski条件),B.Winzell和等人研究了二阶椭圆方程的斜导数问题,关于高阶椭圆方程的非椭边值问题.E.Magenes,G.Stampacchia指出了该问题的解一般说来不具有整体正则性,即若f∈H~r(Ω),一般得不到u∈H~(2m r)(Ω)。本文将在一定条件下建立高阶椭圆方程非椭边值问题解的整体正则性。我们讨论下述问题     

一类非线性梁方程整体解的不存在性

利用两种不同的方法,研究了含有源项和阻尼项的一类非线性四阶波动方程的初边值问题整体解的不存在性,证明了当问题的初始能量E(0)＜d时,d为某正数,问题的解必blowup.     

关于一类非线性Schrdinger方程最佳爆破准则(英文)

考虑如下一类非线性Schrdinger方程iut+Δu+|u|p-1u+E(|u|2)u=0,t≥0,x∈RN,其中,p1,N=2,3,E(|u|2)为非局部奇异积分算子.利用变分方法,给出了上述发展方程解整体存在与爆破最佳判别准则一些最新研究进展的概述.     

关于一类非线性Schr(o)dinger方程最佳爆破准则

考虑如下一类非线性Schr(o)dinger方程iut+△u+| u|p-1u+E(| u|2)u =0, t≥0, x∈RN,其中,p＞1,N=2,3,E(|u|2)为非局部奇异积分算子.利用变分方法,给出了上述发展方程解整体存在与爆破最佳判别准则一些最新研究进展的概述.     

E变换及其应用

E变换系一种级数变换,主要用于求解描述离散系统的差分方程。本文阐述了E变换的基本概念和性质,给出了它的变换法则表和公式表。后面叙述了E变换的应用,包括解差分方程,解差分方程组,解变系数差分方程,解两个自变量的差分方程,以及求级数的和。     

一类非线性波动方程整体解的不存在性

运用PotentialWell方法研究了一类四阶非线性波动方程初边值问题整体解的不存在性 .首先定义了该问题的位势深度d ,然后运用索伯列夫空间中的嵌入定理结合Sobolev Hardy不等式证明位势深度d >0 ,再恰当地构造能量函数E(t) ,运用反证法证明了该问题整体解的不存在性 .当初值满足K(u0 ) <0 ,J(u0 ) 相似文献   

求解矩阵方程A_1XB_1＋A_2X~TB_2=E的一般解

将矩阵方程A1XB1＋A2XTB2=E解表示问题转化为对子矩阵块约束下矩阵方程AYB=E对称解表示问题。应用矩阵的Kronecker积、矩阵广义逆、广义奇异值分解等理论给出矩阵方程A1XB1＋A2XTB2=E解的表示。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the