非线性Volterra延迟积分微分方程多步Runge-Kutta方法的散逸性

将(k,l)-代数稳定的多步Runge-Kutta方法应用于非线性沃尔泰拉延迟积分微分方程,讨论了该方法的数值散逸性,并获得了(k,l)-代数稳定的多步Runge-Kutta方法的有限维和无限维散逸性结论.     

多延迟微分方程Runge-Kutta方法的散逸性

研究了一类多延迟微分方程数值方法的散逸性问题.介绍了GD(l)-散逸性,并证明了代数稳定的Runge-Kutta方法用于此类问题时是GD(l)-散逸的.该结果表明,所考虑的数值方法继承了方程本身的散逸性.     

Volterra泛函微分方程二阶BDF方法的散逸性

本文研究一类Volterra泛函微分方程二阶BDF方法的散逸性.给出了二阶BDF方法的数值散逸性结果,此结果表明所考虑的数值方法继承了方程本身的散逸性.     

中立型多延迟微分方程θ-方法的散逸性

中立型多延迟微分方程广泛应用于生态学、化学等领域,其理论和数值方法的散逸性研究一直是十分重要的课题。本文研究了中立型多延迟微分方程θ-方法的散逸性,给出了θ-方法的数值散逸性结果,此结果表明所考虑的数值方法继承了方程本身的散逸性。     

分段连续型微分方程θ-方法的散逸性

针对带有一个延迟项的分段连续型微分方程,研究θ-方法的数值散逸性.将两种θ-方法:线性θ-方法和单腿θ-方法应用于试验方程,得到数值解为散逸的充分条件.主要定理显示两种θ-方法具有一致的散逸性结果,且都保持了原方程的散逸性.     

Volterra泛函微分方程线性θ-方法的散逸性

研究一类Volterra泛函微分方程数值方法的散逸性问题.给出求解此类问题的线性θ-方法的散逸性结果,结果表明该数值方法继承方程本身的散逸性,数值试验佐证理论结果的正确性.     

基于年龄结构带跳与分数Brown运动种群系统数值解的均方散逸性

讨论了一类基于年龄结构的带跳与分数Brown运动的种群系统数值解的均方散逸性.在一定条件下,利用It?公式、Cauchy-Schwarz不等式和Bwllman-Gronwall-Type估计等证明了所讨论的系统具有均方散逸性.然后讨论了利用分步倒向Euler方法和带补偿的倒向Euler方法得到的数值解的均方散逸性,并给出详细的证明,得到两种数值方法保留了原方程的散逸特性.     

分数Brown运动随机固定资产模型数值解的均方散逸性

讨论一类带分数Brown运动随机固定资产模型数值解的均方散逸性.在一定条件下,根据It?公式和Bellman-Gronwall型引理,得出了模型具有均方散逸性.分别利用分步倒向Euler方法和补偿倒向Euler方法讨论数值解的均方散逸性,并给出数值解散逸存在的充分条件,通过数值算例对所给出的结论进行验证.     

一类比例延迟系统的散逸性

讨论了一类比例延迟系统的散逸性，并证明了变步长Euler方法应用于该系统后仍然保留其散逸性。     

高阶平均向量场方法在Allen-Cahn方程中的应用

Allen-Cahn方程是材料科学中描述流体动力学问题和反应扩散问题中的一类重要方程。Allen-Cahn方程的能量具有散逸性,即能量会随着时间的增长会逐渐降低。在数值模拟中,设计精确地保持Allen-Cahn方程能量散逸性的格式对模拟方程的演化具有显著的优点。目前,保Allen-Cahn方程能量散逸性的数值格式都是低阶的。最近有人构造了保持常微分方程能量散逸特性的高阶平均向量场方法,是一种有效的离散梯度法。国内外还少有人把保能量散逸性的高阶离散梯度方法应用于能量散逸性的偏微分方程。利用高阶离散梯度方法构造了Allen-Cahn方程的高阶格式。新的高阶格式能很好地长时间模拟Allen-Cahn方程数值解的演化,并长时间保持Allen-Cahn方程的内在特性。     

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