具超线性中立项时滞微分方程解的振动性

在α>1且0<β<α情形下,研究了具超线性中立项时滞微分方程[x(t)?pxα(t?τ)]′ q(t)xβ(t?σ)=0,t≥t0,解的振动性.利用一些新的技巧,获得了保证上述方程所有解振动的几乎“sharp”振动准则和至少存在一个非振动解的非振动准则,所得结果补充和扩展了已有文献.     

二阶非线性泛函微分方程解的振动性与渐近性

讨论了两类二阶非线性泛函微分方程(a(t).(y'(t))σ)' q(t)f(y(τ(t)))g(y'(t))=0,(a(t).(y'(t))σ)' q(t)F(y(t),y(τ(t))g(y'(t))=0,其中t≥to,σ为正常数,当t≥to时a(t)>0,q(t)≥0,且q(t)不最终恒为0,τ'(t)>0,且limt→ ∞τ(t)= ∞.利用一些分析的技巧,得到了这两类方程的解振动与渐近性的充分性判据,所获结果可分别应用于σ=奇/奇与σ=偶/奇的情形.改进并推广了已有文献中的相应结论.     

一类三阶非线性中立型时滞微分方程的振动性

主要研究三阶非线性中立型时滞微分方程[a(t)((b(t)(x(t)+p(t)x(σ(t)))’)α)’]’+q(t)f(x(τ(t)))=0,t≥t0,的振动性,其中α是两个正奇数的商且α≥1,给出了弱振动准则,所得结果改进和推广了现有的若干结论.     

一类缺项级数在有理点上值的超越性

我们用N,Q分别表示全体自然数和全体有理数的集合。令σ(z)=sum from n=1 to ∞α_nz~(Cn),(1)其中α_n∈Q,Cn∈N,Cn↑∞。用M_k表示α_1,α_2……α_k的公分母。对于δ>0及a∈N,a≥2定义集合S(a,δ)={p/q|p/q∈Q,(p,q)=1,q≥a,|p|≤q~δ} (2) 本文得到了两个关于σ(z)在有理点上值的超越性的判定定理: 定理1 如果对于级数(1),存在常数A>0使那么,当时,对于任何p/q∈S(a,δ),σ(p/q)是超越数。定理2 如果对于级数(1),存在无穷实数列β_n(n=1,2…)适合其中k_0∈N,K>0是常数。那么,当(4)、(5)、(6)成立时,对于任何p/q∈S(a,δ),σ(p/q)是超越数。     

半线性中立型二阶时滞微分方程的振动准则

研究广义Emden-Fowler中立型时滞微分方程(r(t)|z′(t)|α-1 z′(t))′+q1(t)|x(σ1(t))|β1-1 x(σ1(t))+q2(t)|x(σ2(t))|β2-1 x(σ2(t))=0,t≥t0,其中z(t)=x(t)+p(t)x(τ(t)),β2αβ10.利用广义Riccati变换、积分平均和不等式技巧,给出了该方程的若干新的振动准则,推广了最近文献中的相关结果.     

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 .     

C~n中Stieltjes积分族与几个全纯函数空间的关系

在Cn中讨论了Cauchy-Stieltjes积分族Jp和Bloch型空间、Besov空间、Bergman空间的包含关系,得到如下结果:(1)当0≤qp+1时,Jp βq;(3)当q>p≥0时,Jp Δq;(4)当p>0时,Δp Jp;(5)当0相似文献   

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 .     

具有强迫项正负系数中立型差分方程的振动性

针对强迫项正负系数中立型差分方程Δ(xn-γnxn -r) +Pnxn -τ-qnxn -σ=cn　n≥n0 (1)的振动性 ,给出了该方程在条件n≥n0 时 ,An =γn + n - 1i=n -τ +σqi≥ 1下方程 (1)振动的充分条件。其中cn∈R　γn,Pn,qn∈ (0 , ∞ )　r,τ ,σ∈ { 1,2 ,… }τ>σ。     

半线性中立型Emden-Fowler泛函微分方程的振动准则

建立了中立型Emden-Fowler泛函微分方程(r(t)︱z′(t)︱~(α-1)z′(t))′+q(t)︱x(σ(t))︱~(β-1)x(σ(t))=0,t≥t_0的若干振动准则,推广、统一了半线性微分方程和Emden-Fowler型微分方程的某些振动性结果,其中z(t)=x(t)+p(t)x(τ(t)),α0,β0为常数.最后,通过几个实例说明了结果的正确性.     

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.     

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.     

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