一维混沌系统的非线性反馈控制

提出了一种利用非线性反馈控制混沌的方法。理论分析和数值研究结果表明了该方法的有效性，采用此方法的连续和间歇反馈都能将系统从混沌状态控制到稳定的周期状态。     

Henon系统的混沌控制研究

运用数值仿真的方法,研究了三种控制Henon系统系统混沌的方法,并比较了这三种方法的适应性和控制效果。通过Henon系统在混沌状态下的吸引子、吸引盆、分岔图及其对应的最大Lyapunov指数谱,揭示了Henon系统系统通向混沌的途径。利用数值运算,得到系统的不稳定的周期1和不稳定周期2轨道。通过非线性反馈控制方法、间歇反馈方法和压缩相空间控制法,对系统进行了控制。结果表明,这3种控制方法都可以有效地将Henon系统的混沌状态控制到稳定的周期轨道。     

利用非线性反馈控制Henon混沌系统的低周期态

对混沌系统实施有效控制是利用混沌的重要环节,提出1种利用非线性反馈控制Honen系统混沌运动的方法．根据混沌系统稳定性理论,确定反馈系数的取值范围;利用描绘系统分岔图和计算Lyapunov指数数值研究方法,验证理论分析的正确性．采用连续控制不仅可以实现不动点的镇定,而且可以将混沌系统控制到二周期态;使用间歇控制可以将混沌系统控制到三周期态．该方法控制目标明确,反馈增益的取值范围容易确定。     

时滞反馈法控制含3参数的Sprott N混沌系统

利用非线性动力学理论,讨论了含有3个参数的Sprott N系统的混沌特性.在参数区间b∈[1.8,2.5]上,利用全局分岔图,Lyapunov指数谱准确的表征了系统在此区间内的丰富的非线性行为.应用时滞反馈法对系统的混沌控制进行了详细的理论分析和数值模拟.结果表明,通过该控制法,可将系统的混沌运动控制到稳定的周期运动状态.     

一类混沌系统的非线性反馈控制

提出一种利用非线性反馈控制混沌的方法.根据动力学系统的稳定性理论确定了反馈增益的取值范围:采用分岔图和Lyapunov指数等数值研究,结果表明该方法的有效性.基于这一方法的连续或间歇反馈都能非常有效地将Logistic系统从混沌状态控制到稳定的周期状态.     

时滞位移反馈对一类非对称参数激励系统混沌运动的控制

对一类非对称单自由度参数激励系统施加时滞位移反馈,研究时滞反馈对混沌运动的双向调节作用.定性研究了时滞反馈控制系统复杂行为的机理,结合系统相图,庞加莱截面图和谱分析发现:激励振幅的增大会使得原系统从单平衡点稳定走向倍周期运动和混沌运动;在正反馈的情况下,时滞反馈能够抑制系统的混沌运动,而在负反馈下时滞反馈反而诱发系统的混沌运动.     

Sprott-F系统的混沌控制研究

利用非线性动力学理论,讨论了改进的Sprott-F系统的混沌特性.在参数区b E[0,0.5]上,利用全局分岔图,Lyapunov指数谱准确的表征了系统在此区间内的丰富的非线性行为.应用时滞反馈法、比例微分器控制法和x|x|法对系统的混沌控制进行了详尽全面的理论分析和数值模拟.结果表明,选择适当的反馈系数,通过以上三种控制法,可将系统的混沌运动控制到稳定的低周期状态.     

时滞受控系统非线性动力学行为的数值分析

采用精细积分法和庞加莱截面法计算了不同反馈增益和时滞量情况下的受控系统响应,给出了系统随时滞变化的分岔图和庞加莱截面图,分析了含时滞反馈Duffing方程的分岔、混沌等非线性动力学行为,讨论了时滞和反馈增益对系统非线性特性的影响.结果表明,时滞受控系统的运动形式随着时滞的改变而改变,因此时滞可作为分岔开关来控制系统的运动形式,无论是倍周期运动、拟周期运动或者混沌运动,都可以通过选择合适的时滞量得以实现,并且随着控制增益的增大,系统的非线性特性表现得更加明显.     

一个新离散系统的混沌控制与反控制

研究了一个含有理分式的离散系统的混沌运动，分析了系统参数对系统稳定性的影响．结果表明，系统在适定的参数下处于混沌状态或周期状态．采用压缩映射方法对系统混沌状态实施混沌控制，运用非线性反馈方法对系统周期状态实施反控制，并利用数值模拟验证了所给方法的有效性．     

时滞位移反馈Duffing方程的复杂吸引子及其吸引域

 对时滞线性位移反馈引起的一类单自由度非线性自激振动系统的复杂动力学行为进行研究。所考虑的数学模型为van der Pol-Duffing振子系统加入线性时滞位移反馈而得到的时滞Duffing方程。定性分析了时滞引起的系统Hopf分岔,并通过定量研究发现时滞可引起系统的混沌运动与多种概周期运动共存现象。通过4阶Runge-Kutta法和Monte Carlo方法,划分了不同时滞量下的时滞系统的概周期吸引子和混沌吸引子及其吸引域,发现系统各吸引子吸引域的边界均光滑而不分形,尽管系统出现了混沌运动。研究结果对进一步研究混沌运动机制存在着潜在的应用价值。     

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.     

橡胶颗粒沥青混合料低温抗裂性试验研究

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.     

Jane Eyre——A Feminist In The 19th Century

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.     

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-