首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
目的 建立5个方程新的行波解.方法 借助于双曲正切方法, 有理正余弦方法和正余弦方法.结果与结论 构造了方程有理三角正余弦形式解, 获得了方程周期解, 复数解, 钟形孤立子解.  相似文献   

2.
讨论具有Holling-Ⅱ型响应函数的捕食模型的齐次Neumann问题.首先通过构造上下解的方法研究了该问题半平凡解的全局稳定性,利用Lyapunov泛函和Routh-Hurwitz判定法分别讨论了正常数平衡解的全局稳定性和局部稳定性.其次给出了正平衡解的正的上下界的估计,以及非常数正平衡解的不存在性,最后利用拓扑度的方法研究了非常数正平衡解的存在性.  相似文献   

3.
讨论几类具有分布时滞的Volterra积分微分方程正周期解的存在性和多解性问题.利用锥不动点定理,分别获得了这类问题存在正周期解和存在至少两个正周期解的充分条件,推广和改进了已有文献的相关结果.  相似文献   

4.
本文研究一个带有齐次Neumann边界条件的双分子自催化反应扩散模型的非常数正平衡解.首先给出了正平衡解的正的上、下界估计,其次证明了非常数正平衡解的存在性.  相似文献   

5.
利用重合度理论中的延拓定理讨论了一类积分微分方程模型正周期解的存在性,利用GainesandMawhin[1]重合度理论中的连续性定理以及先验估计研究了一类积分微分方程模型正周期解的存在性,得出了保证正周期解存在的充分条件.此模型还包括了许多著名的生物数学模型作为特例.将此研究结果应用到一些更为具体的生物数学模型,得出了这些模型存在正周期解的充分性判据.研究表明此项研究的结果更为广泛,推广并改进了文献中已有的相关结果.  相似文献   

6.
无穷时滞泛函微分方程正周期解的存在性与多解性   总被引:1,自引:0,他引:1  
应用非线性泛函分析理论中的不动点指数定理、算子理论与锥理论,讨论了一类泛函微分方程的正周期解问题,与已往文献结果相比,研究结果不但获得了该类方程正周期解的存在性定理,而且在此基础上获得了该类方程正周期解的多解性定理.最后,利用Hematcpoiesis模型说明了所得结论在研究具有无穷时滞泛函微分方程正周期解的存在性与多解性问题中的有效性.  相似文献   

7.
在对N体问题中心构型的研究中,正多边形解是研究对象之一.其特点是,N个等质量的质点,位于一个正N边形的顶点上.有没有2 N个质点,构成一个正N边形解呢?即N个等质量的质点,位于一个正N边形的顶点上,另外N个等质量的质点,位于该正N边形的边的中点.本文研究了这种解的存在条件,并给出了具体的解.  相似文献   

8.
讨论一类带有内部存储和抑制剂的非均匀恒化器模型正平衡解的存在性.由于模型中比率项的奇性,导致通常的线性化方法对本模型并不适用.为克服这个困难,首先建立模型正平衡解细致的先验估计,该估计表明模型的正平衡解含于一个特殊的锥内.然后借助一类非线性特征值问题的主特征值及锥上的不动点指标理论给出了模型正平衡解存在的充分条件.结果表明当其对应的非线性特征值问题的主特征值满足一定关系时,系统至少存在一个正平衡解.  相似文献   

9.
主要考虑了具有Crowley-Martin型功能性反应的非自治捕食者-食饵系统的正周期解问题.在系统参数是周期的情形下,利用重合度延拓定理建立非自治捕食者-食饵系统的正周期解和边界周期解的存在性.最后,利用数值模拟验证和补充了该理论结果.  相似文献   

10.
讨论了一类食饵带有传染病的带Neumann齐次边界条件的反应扩散模型的正平衡态问题.给出了正平衡态解的先验估计及非常数正平衡态解的存在性和不存性及分歧.  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.
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   

15.
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   

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.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

19.
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   

20.
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   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号