Belousov-Zhabotinsky反应中的周期电反馈效应

讨论了BZ反应的Oregonator(俄勒冈)模型在周期反馈下的动力学行为.指出无反馈存在时,系统可能存在稳定的平衡态,并由Hopf分岔导致周期振荡.而当周期扰动存在时,随着扰动幅值的逐步增大,系统由周期增加分岔直至无穷导致混沌.混沌失稳后产生不同周期的振荡,并由周期增加分岔引起另一混沌吸引子.     

系统x··+RF''''(x)x·+1/L F(x)=Ae(t)

该文研究系统ｘ＋ＲＦ＇（ｘ）ｘ＋１ＬＦ（ｘ）＝Ａｅ（ｔ）Ｆ（ｘ）＝∑ｎｉ＝０ａ２ｉ＋１ｘ２ｉ＋１出现的概周期振荡现象，结合运用Ｌｉａｐｕｎａｖ函数，获得了系统产生概周期振荡的先兆性条件，为避免系统产生概周期振荡提供了参考数据。     

一个生化系统的周期行为

本文定性地研究了一个生化反应系统的自治周期行为,得到了此系统周期振荡产生的条件和不产生的条件。     

具有周期强迫的Filippov Brusselator系统的动力学研究

通过利用阈值策略控制(TPC),本文提出了一个具有周期强迫的Filippov Brusselator系统.基于Brusselator系统的平衡点的存在性和稳定性分析,研究了Filippov Brusselator系统的滑动周期解的存在性和稳定性,以及滑动区域与周期解之间的关系,并采用数值模拟探究了不同的关键参数对其周期解振荡模式的影响.结果表明:当关键参数发生变化时,该系统的周期解的振荡模式也会发生变化.     

黑洞双星高频准周期振荡3∶2∶1频率比的理想模型(英文)

在Blandford-Znajek(BZ)过程和非轴对称磁场的磁耦合(MC)过程共存模型的基础上解释了黑洞双星XTE J1550-564令人困惑的高频准周期振荡(HFQPO)的3∶2∶1频率比.结果表明:高频准周期振荡中的两个频率可以用MC过程导致的两个旋转热斑来拟合,另外一个高频准周期振荡频率与BZ过程产生的磁热斑有关.进一步地,讨论了与黑洞双星XTEJ1550-564高频准周期振荡、喷流以及态转变相关的天体物理环境.     

基于比率的Holling-Tanner干扰扩散系统的周期解

利用重合度理论中的延拓定理,讨论具有比率依赖和时滞的Holling-Tanner干扰扩散系统全局正周期解的存在性,得到了保证周期解存在的充分条件.结果表明,当食饵种群的內禀增长率大于其总消耗率时系统将产生生物性周期振荡.     

具时滞物价瑞利方程的动力学性质

以滞量r为分支参数,研究了具时滞的物价瑞利模型的动力学行为,这些行为包括:系统在平衡点附近的稳定性,局部Hopf分支的存在性,发生条件、Hopf分支的方向,分支周期解的稳定性以及分支随参数变化其周期解的周期变化.最后通过数值模拟验证了理论分析结果,并用分支理论解释了物价瑞利模型产生且维持周期振荡的原因.     

电力系统在周期扰动下的混沌研究

为了研究电力系统在周期扰动下产生混沌的现象,提高电力系统的稳定性,将单机无限大系统转化为周期干扰下的Hamilton系统,并利用Melnikov方法研究电力系统产生混沌的物理条件.推导了Melnikov函数具有简单零点的条件,得出了产生混沌的参数区域,为准确判别混沌振荡提供了计算依据.理论分析和数值仿真表明,如果扰动功率较小,则不会产生混沌;如果扰动功率较大,系统将出现混沌.     

含磁准零刚度隔振器的非常规分岔

通过并联具有负刚度特性的磁力弹簧与线性正刚度弹簧,设计了一种新型含磁准零刚度隔振器模型,并推导出其无量纲化动力学方程.运用分岔图、时间响应图、相平面图、最大Lyapunov指数图等揭示了该系统的复杂非线性簇发振荡形式,发现了一种新颖的非常规分岔行为,多次切分岔导致周期簇发振荡与混沌簇发振荡反复交替,周期簇发振荡反复出现跨临界分岔.此现象表明,这类含磁准零刚度隔振器的动力学分岔行为敏感依赖于系统参数,外激励频率的变化导致系统产生不同形式的簇发振荡现象.     

L-D循环对果蝇生理活动的影响

针对Goldbeter五维果蝇生理节律模型进行了分析,得出系统平衡点的渐近稳定性条件,同时分析了果蝇的生理节律.在L-D循环光照作用下,当果蝇的生物钟处于渐近稳定条件时,利用摄动理论证明系统可以产生周期振荡,且当果蝇的生物钟具有周期解时,系统在一定条件下可能出现倍周期现象.     

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