微分反馈控制与延迟微分反馈控制

证明了微分反馈控制洛伦兹系统在三个平衡点S0，S1和S2的可控性，提出了延迟微分反馈控制DDFC，DDFC利用可测变量的微商进行反馈，理论证明DDFC加于洛伦兹系统的第3个方程时3个平衡点均不稳定可控，而加于洛伦兹系统的第2个方程时平衡点S0不可控而平衡点Sl和S2稳定可控，用Matlab进行数值仿真，调节延迟时间τ和控制增益k，DDFC系统能自动寻找和稳定不同的不稳定周期轨道UPO，实现混沌控制。     

Chen氏混沌系统的周期扰动控制

设计出反馈控制器和自适应控制器对Chen氏系统进行了有效控制;在反馈控制中,从理论上严格推导出将系统分别控制到零点和非零平衡点的控制参数k的范围;在此参数范围内,设计出周期扰动反馈控制器,可以将系统从不动点控制到周期轨道上.在自适应控制中,设计出自适应周期扰动控制器,也可以实现此目标;最后,研究了周期扰动函数对最后稳定周期轨道的影响.数值实验证明这种方法是切实有效的,也证明了周期扰动函数对最终周期轨道的影响.     

超混沌Lü系统的反馈控制

针对动力学行为更丰富更复杂的超混沌系统的控制问题,研究了最新提出的超混沌Lü系统的反馈控制问题,设计了一种线性反馈控制LFC(linear feedback control)和一种微分反馈控制DFC(differential feedback control)方法.用稳定性理论对反馈控制超混沌Lü系统的可控性和稳定性进行理论分析,理论分析和数值仿真都表明受控超混沌Lü系统可稳定地收敛到平衡点.采用文中的微分反馈控制DFC,通过调节控制增益,可以发现超混沌Lü系统不同的不稳定周期轨道UPO(unstable periodic orbit),并控制超混沌Lü系统到不同的不稳定周期轨道UPO.     

延迟微分反馈法控制混沌

利用可测变量的微商进行反馈,提出了用延迟微分反馈控制(DDFC:DelayedDifferentialFeedbackControl)实现混沌控制的方法。理论证明了微分反馈控制和DDFC控制Lü系统3个平衡点的稳定可控性。在Matlab进行了数值仿真,结果表明,通过调节延迟时间τ和控制增益k,DDFC系统能自动寻找和稳定不同的不稳定周期轨道(UPO:UnstablePeriodicOrbit),实现混沌控制。     

超混沌Lv系统的反馈控制

针对动力学行为更丰富更复杂的超混沌系统的控制问题,研究了最新提出的超混沌Lv系统的反馈控制问题,设计了一种线性反馈控制LFC（linear feedback control）和一种微分反馈控制DFC（differential feedback control）方法．用稳定性理论对反馈控制超混沌Lv系统的可控性和稳定性进行理论分析,理论分析和数值仿真都表明受控超混沌Lv系统可稳定地收敛到平衡点．采用文中的微分反馈控制DFC,通过调节控制增益,可以发现超混沌Lv系统不同的不稳定周期轨道UPO（unstable periodic orbit）,并控制超混沌Lv系统到不同的不稳定周期轨道UPO．     

变量延迟反馈法控制连续混沌系统的仿真实验

给出了应用PSPICE仿真平台,实现用变量延迟反馈(DFC)法控制连续自治电路系统混沌的仿真实验.结果表明:只要恰当地选择延迟时间和反馈系数,通过微扰控制即可得到混沌轨道中不稳定的周期轨道.     

碰摩转子映射系统的延迟反馈混沌控制

采用延迟反馈混沌控制方法对四维分段光滑碰摩转子映射系统进行混沌控制，通过选取合适的控制增益参数，可将碰摩转子映射系统的混沌运动控制到有规则的擦边周期1轨道或单点碰摩周期2轨道，并通过数值模拟证实了分析结果．     

一种控制蔡电路的分岔和混沌的方法

提出了用系统单变量的比例微分反馈实现蔡电路的分岔和混沌控制的方法.首先根据理论分析求出使蔡电路中不动点稳定的k1的取值范围和使系统发生Hopf分岔的临界值k0,然后对受控的系统做出了以k1(k1>k0)为控制参量的系统分岔图.由分岔图可以得到将系统控制到各种nP周期轨道的k1的取值范围,在这些范围内适当选择k1值,可以将蔡电路控制到1p,2p,3p,4p,6p和8p等周期轨道.数值仿真结果验证了这种控制分岔和混沌方法而且证明了理论结果的正确性.     

延迟反馈法控制Rossler系统的解析研究

用解析方法研究了延迟反馈法控制Rossler系统的问题。利用延迟系统出现Hopf分支的条件及处理方法，给出控制参数的一般解析条件。通过数值计算，在由解析分析得到的控制条件下，系统的不稳定周期轨道被稳定住。     

立方混沌系统的多种目标控制

运用系统变量的状态反馈与参数调整的混合控制策略,对立方混沌系统实施多种目标的混沌控制.理论研究和数值仿真表明:控制方法能实现离散混沌系统的倍周期分岔控制,通过延迟和抑制分岔,确保在较宽的参数范围内达到规则行为;能稳定嵌套在混沌吸引子中的不稳定周期轨道;实现变轨控制,即通过选择合适的调整参数,将系统从一个2n周期轨道控制...     

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