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1.
§1引言本文沿用[1]、[2]中的记号和定义.设α_t(ω)(0≤t<ξ(ω))是齐次马尔可夫过程X=(x_t,(?),M_t,P_x)的几压缩几齐次几可乘泛函(详细定义见后),则(?)(t,x,Γ)=M_x(XΓ(xt)α_t)(t≥0,x ∈E,Γ∈(?))定义相空间(E,(?))上一转移函数.从直观看来,这相当于以一定的规律缩短原过程的生命而得到一新的转移函数,α_t 给出在时间区间[0,t]内生命不缩短的概率.(?)(t,x,Γ)对应的半群算子是  相似文献   

2.
研究广义Logstic型泛函微分方程x′(t)+[1+x(t)]F(t,x[·]α)=O(t≥O,α≥1)零解的全局吸引性.运用一些分析方法和技巧,对该方程的零解作出估计,得到方程零解是全局吸引的一些充分条件,结果推广并改进了现有文献中的相关结论.  相似文献   

3.
本文讨论扰动矢量方程dx_。,.’、—‘I、t,X少dt(1)其中:x=(x,,xZ,……,x。)堤R”空I’ed的矢量,f(t,x)是定义在I火Rn空l’ul 0(t<+co,}lx{l<+二(2)上的n维连续矢量函数,f(t,。)三。,满足解的存在及唯一性条件,并且假定解可以开拓到t二+co。 约定x二x(t;x“,t。)表示方程(1)满足初始条件x(t。)二x“的解。 本文的目的在于提出微分方程(1)的零解全局稳定和全局渐近稳定的充要条件。 定理1方程(1)的零解x二O全局稳定·‘的充要条件是:在1 XR“空间 t)t。.{{x}}<+co(3) 内存在无限大定正函数V(t,x),满足条件 V(t,x(t;x“,t。))(V(t。,x…  相似文献   

4.
本文主要讨论一类具有时滞的奇异微分积分方程Ex(t)=Ax(t)+f(t,x(t),x(t-r(t)))+∫/t-rg(t-s,x(s))ds,t≥t0,其中,[f(t,x,y)]+≤B[x]+L[y]+,[g(t-s,x(s))]+≤H(t-s)[x(s)]+.首先,阐述本文研究背景和意义,给出奇异微分积分方程指数稳定、Dini导数和M-矩阵的定义,以及一些必要的数学记号的含义.然后,利用分析技巧和方法并结合M-矩阵的性质,建立一个广义时滞微分积分不等式.最后,借助于建立的广义微分积分不等式,获得了含时滞的奇异微分积分方程零解全局指数稳定的一个充分条件,即当D∈M,D=-(A+B+L+r∫0H(s)ds),那么方程的零解是全局指数稳定的.  相似文献   

5.
通过不等式的推导,研究广义Logistic型泛函微分方程x'(t)+[1+x(t)]F(t,x[·])=0零解的全局吸引性.其中:t≥0,0<α≤1且α为两正奇数之比,F(t,Φ)是[0,+∞)×Ct上的连续泛函.将所得到的结果运用到方程讨论中,改进并推广了其他文献的一些结果.  相似文献   

6.
一类非线性二阶微分方程全局渐近稳定的充要条件   总被引:1,自引:0,他引:1  
本文研究如下一类二阶非线性方程(组)全局稳定的充要条件(Ⅰ)(a(t)x')' p(t,x,x')f(x)φ(x') q(t)g(x)h(x')=e(t,x,x')约定上述方程或方程组中出现的函数均在区域t≥0,|x| |y|<∞连续  相似文献   

7.
在适当的条件下研究二阶微分方程 x+p(x,x,t)f(x)Φ(x)+q(t)g(x)h(x)=e(x,x,t)及其特殊方程的零解x=x=0为全局渐近稳定的或一切解及其导数均趋向于(0,0)的充要条件。并在具有无界阻尼的条件下,对p(x,x,t)给出一个增长条件,以保证其零解为全局渐近稳定或一切解及其导数均趋向于(0,0)。  相似文献   

8.
设G是有限群,(?)是G的Cayley—子集.用X(G,(?))表示G关于(?)的Cayley图,其中V(X)-G,E(X)-{((?),)|(?)∈G,(?)∈(?)),本文证明了:对于(?)ilton群G,若X(G,(?))是连通的,则X(G,(?))有Hamiltonian(?)另外.本文也对有限交换群情形给出一个简单证明。  相似文献   

9.
讨论一类微分差分方程 x(t) =gradG(x(t) ) +f(t,x(t-r) )的周期解问题 ,其中x(t) =(x1(t) ,… ,xn(t) ) T 是n维连续向量 ,G(x)为连续可微函数 ,r>0 ,f(t,x)是n维连续向量函数 ,且f(t+ω ,x) =f(t,x) ,ω>0。利用重合度理论中的延拓定理并构造Lyapunov泛函得到了周期解的存在性和全局吸引性定理。改进并扩充了文 [3]的有关结果。  相似文献   

10.
利用L iapunov函数法,给出两类方程…x g(x。)x。 bx。 f(x)=e(t,x,x,。x。)和…x g(x。)x。 f(x)x。 cx=e(t,x,x,。x。)零解全局渐近稳定性的充分条件,推广文献[1~4]中的相关结论.  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.
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   

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.
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   

15.
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.  相似文献   

16.
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   

17.
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   

18.
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   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
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   

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