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1.
文章主要研究了如下方程的振动性(r(t)|(x(t)+p(t)x(τ(t)))′|α-1(x(t)+p(t)x(τ(t)))′)′+q0(t)|x(τ0(t))|α-1x(τ0(t))+∑ni=1qi(t)|x(τi(t))|βi-1x(τi(t))=e(t),t≥T.其结果推广和改进了已有结论.  相似文献   

2.
讨论了一类奇异扩散方程ut=Δu^m+f(u)具齐次Neumann边值条件解的渐近性质.结果表明:1)若f(u)=-u^α,且u(x,t)是该问题在QT上的解,则t≤T0,此处T0=(max u0 x∈Ω)^1-α/(1-α) ;2)存在正常数c1,δ1,c2,δ2,使得‖▽u^m‖L^2(Ω)≤c1e^-δ1t以及‖u‖L^2(Ω)≤c2e^-δ2t.  相似文献   

3.
一阶双滞量时滞方程零解渐进稳定的充要条件   总被引:1,自引:1,他引:0  
考虑以下方程x(t)+I(b)x(t)+bx(t-τ)+cx(t-2τ)=0其中b,c,τ是常数,并且τ〉0,bc≠0,I(b)=2 0148τ[27(bτ)4-576(bτ)2-1 024],建立了方程零解渐进稳定的充要条件,易于检验和应用.  相似文献   

4.
运用上下解方法研究二阶边值问题这里0<α≤b<1,α,β,γ,δ,ζ,η>0,A,B均为给定的实数,且ρ:=αγ+αδ+βγ>0,f为满足Nagumo条件的Caratheodary函数.此问题有解当且仅当有一个上解y和一个下解x,且对所有的0≤t≤1,都有x(t)≤y(t).  相似文献   

5.
高阶非线性中立型方程的振动性   总被引:3,自引:2,他引:1  
研究了一类具有连续分布滞量的高阶非线性中立型方程{α(t)Ψ(x(t))[x(t) m↑∑↑i=1ci(t)x(τi(t))]^(n-1)}′ ∫α^bq(t,ζ)f(x(g(t,ζ)))dσ(ζ)=0的振动性,利用Riccati变换并运用数学分析方法和技巧,得到了该类方程新的振动准则。  相似文献   

6.
通过运用不等式和积分平均技巧,给出了一类形如 [r(t)|(x(t)+p(t)x(t-τ))′|^α-1(x(t)+p(t)x(t-τ))′]′+q(t)f(x[σ(t)])=0的二阶半线性中立型时滞微分方程的区间振动性判据,改进推广了一些已知的判据.  相似文献   

7.
研究了如下混合积分不等式up(x,y)≤a(x,y)+b(x,y)f^a(x0∫^a(x)0∫^∞βy[c(s,t)u(s,t)+e(s,t)]dtds,u^p(x,y)≤a(x,y)+∫a(x)0b(s,y)[u(s,y)])^pds+∫α(x)0∫^∞βy[c(s,t)u(s,t)+e(s,t)]dtds及u^p(x,y)≤a(x,y)+∫^a(x)0b(s,y)[u(s,y)]^pds+∫^α(x)0∫^∞βyF(s,t,u(s,t))dtds,并给出了其具体的应用实例.  相似文献   

8.
本文主要利用H( t,s)型函数和广义Riccati变换技巧,建立二阶中立型时滞拟线性微分方程[r(t)|x′(t)|γ-1x′(t)]′+q0(t)|y(t -σ)|γ-1y(t -σ)+q1(t)|y(t -σ1)|α-1y(t -σ1)+q2(t)|y(t -σ2)|β-1y(t -σ2)=0.其中x(t)=y(t)+p(t)y(t-τ),在0≤p(t)≤1的新的振动准则.  相似文献   

9.
无穷区间上二阶多点边值问题的多个正解的存在性   总被引:1,自引:0,他引:1  
利用Leggett-Williams不动点定理,得到了无穷区间上二阶多点边值问题{x″(t)+q(t)f(t),x′(t))=0,t∈J+,x(0)=^m-2∑i=1αix(ζi),x^′(∞)=0,3个正解的存在性结果.  相似文献   

10.
利用积分平均技巧和Hardy,Littlewood&Polya不等式建立了一类二阶非线性微分方程[r(t)|x′(t)|^α-1x′(t)]′+q(t)(|x|^α-1x+β|x|)=0的振动性判据,其中0≤β〈1为常数.所得结果将已有的部分结果推广到更加广泛的方程上,并完善了Manojlovic(1999)的证明过程.  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

14.
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.  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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-  相似文献   

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