具有正负项的高阶中立型差分方程的振动性

讨论了具有正负项的高阶中立型差分方程△[an△m-1(x(n) pnx(n-τ))] f(n,x(n-σ))-g(n,x(n-ρ))=0.其中:△是前差分算子,△xn=xn 1-xn;m为正整数;ax,pn为非负实数序列;τ,σ,ρ为非负整数;f(n,u)和g(n,υ)为连续函数.建立了有界振动及有界概振动的判别准则.     

一类二阶非线性时滞差分方程的振动性

利用分析技巧,结合Riccati变换,研究了方程Δ[(xn+anxn-τ)kΔ(xn+anxn-τ)k]+bnf(xn-σ)=0,n≥n0在系数an,bn满足不同条件下的振动性,并举例说明.     

二阶非线性中立型差分方程的始终正解

研究了二阶非线性中立型差分方程Δ(a(n)Δ(x(n) p(n)x(n-τ))) f(n,x(σ(n)))=0的非振动性.利用Banach压缩映射原理,得到了这个方程具有某种极限性质的始终正解的存在性定理.     

一类中立型差分方程非振动解的存在和渐近性

讨论了非线性多时滞中立型差分方程　　　　Δ(x(n) - p(n)x(n-τ) ) +q(n) ∏mi =1(x(n -σi) ) αisgnx(n-σi) =0的非振动性 .其中 :p(n) ≥ 0 ,q(n)≥ 0且不恒等于 0 ;τ ,σi 是非负整数 ,i=1,2 ,… ,m ;αi >0 ,∑mi =1αi =1;Δ是前差分算子 ,Δx(n) =x(n+1) -x(n) .利用序列及映射的构造得出了方程最终正解的存在条件 ,并且引用以指数形式趋于 0的定义讨论了非振动解的渐近性态 .     

具正负系数的多滞量中立型差分方程的振动性

讨论了具正负系数的多滞量中立型差分方程Δ[x(n)-m∑l=1Rl(n)x(n-rl)] w∑i=1Pi(n)x(n-τi)-k∑j=1Qj(n)x(n-σj)=0的振动性.其中:w≥k;Rl,Pi,Qj∈([n0,∞),R );rl,τi,σj都是非负整数,并且关于l,i,j都是单调减的,τi≥σi.在新的条件下得到了该方程振动的充分条件.     

一类三阶非线性中立型时滞差分方程的振动性和渐近性

本文研究了一类三阶非线性中立型时滞差分方程Δ3(a(n)x(n)-b(n)x(n-τ)) q(n)f(x(n-σ))=0的振动性,得到了该方程振动的一个充分条件及其有界的非振动解趋于零的判据.     

一类非线性多时滞中立型差分方程的振动性

讨论了非线性多时滞中立型差分方程　　　　Δ(x(n) - p(n)x(n-τ) ) +q(n) ∏mi =1(x(n -σi) ) αisgnx(n-σi) =0的振动性 .其中 :p(n) ≥ 0 ,q(n)≥ 0且不恒等于 0 ;τ ,σi是非负整数 ,i=1,2 ,… ,m ;αi >0 ,∑mi=1αi=1;Δ是前差分算子 ,Δx(n) =x(n+1) -x(n) .采用离散的Riccati变换和某些函数变换 ,利用反证法 ,得出了此方程所有解的若干振动准则 .     

奇数阶非线性中立型时滞差分方程的振动性

研究了一类奇数阶非线性中立型时滞差分方程Δd(a(n)x(n)-p(n)x(n-τ))+q(n)f(x(n-σ))=0的振动性,得到了该方程振动的若干充分条件,推广并改进了现有文献中的结果.     

三阶非线性差分方程的振动性

利用分析方法研究了三阶非线性差分方程Δ[bnΔ(anΔxn)]+qnf(xσ(n))=0,n≥n0的振动性,并举例说明.     

一类高阶非线性中立型差分方程的振动性

研究了一类高阶非线性中立型时滞差分方程Δd(a(n)x(n)-p(n)x(n-τ))+sΣj=1qj(n)fj(x(n-σj))=0的振动性,得到了该方程振动的若干充分条件,推广了现有文献中的结果.     

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.     

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.     

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.     

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.     

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.     

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-