关于Lienard方程极限环的唯一性

本文研究了Liénard型方程X f(x)x x=0的极限环的唯一性,所得结果推广了张芷芬的极限环唯一性定理.     

RFDE的解的唯一性与Liapunov泛函

本文讨论RFDE的解的唯一性与Liapunov泛函之间的关系,即用V(t,Φ)讨论RFDE的解的唯一性问题,由RFDE的唯一性来讨论V(t,Φ)的存在性问题。     

常微分方程解的存在唯一性定理的推广

推广了一阶微分方程dx/dt=F(t,x)初值问题解的存在唯一性定理,在F(t,x)满足Holder条件下,利用压缩映射原理证明了微分方程解的存在唯一性.     

差分多项式分担不动点的唯一性

利用Nevanlinna基本理论和基本方法,研究了差分多项式fnf(z+c)分担不动点的唯一性问题,得到了关于差分多项式的唯一性定理,改进了文献[5]的结果。     

二阶线性椭园、抛物型方程广义解的唯一性定理和最大值原理

本文在限制(8)、(9)下,给出了二阶线性椭园型方程广义解的唯一性定理和最大值原理之间的等价性,又在限制(19)和(20)下,证明了二阶线性抛物型方程广义解的唯一性定理和弱最大值原理。     

一类函数微分方程解析解的存在性和唯一性

在本文中,我们研究了函数微分方程xf'(x)-(sum(a_mα_mxf'(α_mx)) from m=1 to S)-sum(b_nf(β_nx)h(x)) from n=1 to T的解析解的存在唯一性。给出了方程(1)解析解的存在唯一性定理。     

双曲型方程的一类反问题

本文讨论了确定双曲型方程U_(tt)(x,t)-U_(xx)(x,t)+q(x)(U_t(x,t)+U(x,t))=F_(x,t)中未知系数q(x)的反问题,证明了此类方程柯西问题古典解的存在唯一性,得到了等价于反问题的含未知函数q(x),u(x,t)、U_t(x,t)、U_(tt)(x,t)的非线性积分方程组,证明了其局部解的存在唯一性,从而得到了反问题解的存在唯一性。     

基于广义位势理论的岩土塑性应变增量方向非唯一性问题

基于广义位势理论提出的考虑拟弹性的弹塑性模型(拟弹性弹塑性模型)把总的塑性应变分解为满足弹性分解准则的拟弹性部分和符合传统塑性理论假设的纯塑性部分,这样分解后建立的模型更为合理和简便,同时又可以解决岩土塑性应变增量方向非唯一性的问题。研究结果表明:基于广义位势理论的拟弹性弹塑性模型的模拟效果较好,传统的弹塑性模型只能反映塑性应变增量方向的唯一性,而拟弹性弹塑性模型则能够同时反映塑性应变增量方向的唯一性(高应力水平时)和非唯一性(低应力水平时),结果更符合实际,从而为解决塑性应变增量方向非唯一性问题提供了一种有效的方法。     

若干弹性力学问题解的唯一性定理

弹性力学问题解的适定性,包括存在性、唯一性以及稳定性(对边界条件的连续依赖性).其中解的唯一性定理是求解定解问题的一个有力工具,为各种求解方法提供理论依据,解是否满足唯一性是弹性理论的一个基本问题.然而,在物理上三维弹性问题存在非唯一解的例子广泛存在,其相应的数学模型并不能要求解的唯一性定理无条件成立.因此解的唯一性需在一定的条件下成立,如弹性张量、应变能函数和变形范围的限制条件.本文回顾了解的唯一性定理在弹性理论中的背景和发展历史,重点介绍了线性弹性理论、有限变形非线性弹性理论和具有初始应力场的弹性理论中边值问题的解的唯一性定理,给出了其中重要定理的证明方法.在此基础上,结合研究进展提出了弹性力学问题解的唯一性定理的待解决问题.     

无限时滞泛函微分方程概周期解的存在性和唯一性(英文)

以(C g,|·|g)为相空间,利用Liapunov泛函的方法研究了无限时滞泛函微分方程概周期解的存在性和唯一性,得到了方程概周期解的存在性和唯一性的新的判据.     

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.     

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.     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-