闭二维流形上的POINCARE—BENDIXSON型定理

对于平面二维自治系统,有著名的Poincare′—Bendixson定理:如果C~ 是一条有界正半轨线,而其W极限集Q(C~=)不含奇点,则或(i)C~ =Ω(C~ ),或(ⅱ)Q(C~ )=■-C~ ,在任何情况下,此处之Ω(C~ )都是闭轨线。对于二维流型M~2上的流,由于非闭P~-(P~-)稳定轨线可能存在,W极限集的构造一般说来是比较复杂的。余树祥[1]证明了:对于闭的二维流形(可定向或不可定向)M~2上定义的连续流f(除了环面T~2上无休止点的流之外)任何正半轨线f(P,R~-)的W极限集Ω_P如果不含休止点,则它必     

连结平面奇点轨线的存在性

对C1平面流f,如果存在点p0∈R2及奇点p1,p2,使得lim t→ ∞f(P0,t)=p1,lim t→-∞f(P0,t)=p2,称f(P0,R)是连结奇点p1,p2的轨线.利用连结弧的半有界性,得到了一些判别仅含2个奇点的平面动力系统连结轨线存在的准则.     

集值离散动力系统的极限行为

设(X,d)为紧致度量空间,f:X→X连续,K(X)是由X的所有非空紧致子集构成的集族,H是由d所诱导的Hausdorff度量,则(K(X),H)是由X的所有非空紧致子集构成的紧致度量空间,-f:K(X)→K(X)连续,-f(A)={f(x):x∈A}研究了-f的扩张性、点态稳定性、性质p、链可迁(混合)、伪轨跟踪性质,以及这些极限行为在(X,f)与(K(X),-f)之间的内在联系。     

三阶自治系统的相空间的一个性质

本文研究了,一个三阶自治系统,证明了该系统的相空间有闭轨线,但没有奇点。从而得出三阶自治系统的相空间虽有闭轨线,但可以没有奇点。研究下面三阶自治系统这里,f(x,g,z)为实变量的实函数,且对于任意的(x,y,z)∈R~3有f(x,y,z)>0。取V_1=x~2+y~2-1=0,V~2=z=0。通过(1)求得     

含函数微分的积分不等式

利用变分方法构造并证明了含变元微分的积分不等式方法,并用该方法推广了Hilbert不等式和Opial不等式,求出了下述不等式的最优常数: ∫Ω∫ΩF(x,y)f(x) g(y) dxdy≤C[∫Ωp(x)[Dβ1f(x))]2dx∫Ωp(x)[Dβ2g(x)]2dx]1/2, C1∫Ωp(x)[Dαf(x)]2d...     

一类半线性退化抛物方程的全局吸引子

利用Sobolev嵌入定理和渐近先验估计方法研究一类半线性退化抛物方程在?tu(x, t)=Δ_λu(x, t)+f(u(x,t))+g(x)解的长时间行为,其中非线性项f满足任意p-1(p≥2)次多项式增长,得到了半群{s (t)}_(t≥0)在L~2 (Ω),L~p(Ω)(p2)中的紧性,并由此得到L~2(Ω),L~p(Ω)中全局吸引子的存在性。     

树映射拓扑熵为零的几个充要条件

研究了拓扑熵为零的树 (即一维紧致连通不含圈的分支流形 )映射 ,其ω-极限集的特征 ,得到了 :设 f :T→ T是连续自映射 ,则 h(f ) =0充分且必要条件是对任意的 x∈ T,ω(x,f )或者是周期轨 ,或者是不含任何周期轨的无限集。此外 ,在系统具有伪轨追踪性质的假设下 ,得到了 h(f ) =0的另一个充分必要条件是 AP(f ) =R(f ) ,这些结果都推广了区间映射的相应结论。     

(PS)条件的证明

1 预备知识 定义1 记W0k,p(x)(Ω)的共轭空间为W-k,p'(x)(Ω),定义W-k,p'(x)(Ω)的范数如下: ‖ G ‖-k,p'=sup(|G(f)|)/(‖f‖k,p):f∈W0k,p(x)(Ω).     

带临界指数非线性椭圆方程非平凡解的存在性

讨论了有界区域上的Dirichlet问题-△u-λu=α(x)│u│~(p-1)u+f(x,u),x∈Ω,u=0,x∈Ω非平凡解的存在性。其中 p=(n+2)/(n-2),n≥3,f(x,u)是关于│u│的增涨阶低于p的连续函数,λ是正参数。我们先证明了一个不具(PS)条件的临界点定理。据此并利用Sobolev嵌入定理的最优常数,克服了失去紧性的困难,从而得到非平凡解的存在性。与Brezis—Nirenberg结果不同的是,我们没有假设λ<λ_1,λ_1是-△:H_0~1(Ω)→H~(-1)(Ω)的第一本征值。     

p(x)-Laplacian Dirichlet问题无穷多解的存在性

在变指数Lebesgue空间L~(p(x))(Ω)和变指数Sobolev空间W~(k,p(x))(Ω)理论框架下,研究了下面的p(x)-Laplacian Dirichlet问题:{-div[(d+|▽u|~2)~(p(x)/2-1)▽u]=f(x,u),x∈Ω:u=0,x∈Ω其中ΩR~N是有界区域,p(x)1,p(x)∈C(Ω),d0为常数.利用p(x)-Laplace算子-div[(d+|▽u|~2)~(p(x)/2-1)▽u]的性质及喷泉定理证明了这个问题无穷多个弱解的存在性.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

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

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.