一类利普希茨非线性系统的全局有限时间控制

讨论了一类Lipschitz非线性系统的全局有限时间控制问题,利用Lyapunov稳定性理论,齐次系统理论及系统局部有限时间稳定性理论,给出了一个连续非光滑的状态反馈控制器存在的充分条件,它能将满足全局Lipschitz条件的非线性系统在有限时间控制到平衡点.最后,通过仿真实验验证了方案的有效性.     

混沌系统的RBF网络补偿控制方法研究

针对混沌系统由线性和非线性两部分构成的特点,提出径向基函数网络(RBFNs)补偿控制非线性混沌运动的方法,用训练好的RBF网络消除混沌系统非线性因素影响,将原系统变成近似线性系统,再利用设计好的线性状态反馈控制器将混沌系统镇定到希望平衡位置.在理论分析的基础上,通过典型的连续时间混沌系统(Holmes非线性振子)进行计算机仿真实验,结果表明,所提出方法具备有效性.图4,参12.     

电动车用IPMSM损耗最小化电流求解方法

为了实现电动车用IPMSM的实时效率优化控制,实时地求解电机的损耗最小化电流,提出一种基于投影动态系统的IPMSM损耗化最小化电流求解方法.该方法首先将电机效率优化控制建模为基于转矩、电流和电压约束的优化问题;接着将该优化问题分为两种情况考虑,即损耗最小化电流处在电压约束区域内和约束边界上,利用优化理论将每种情况的电流求解转化为非线性方程组的求解;最后利用投影动态系统实现该非线性方程组的求解.基于投影理论和矩阵范数理论分析得出该动态方系统的收敛条件,该条件简单且易于求得.仿真结果表明该方法有效且正确.     

具有非线性扩散和时滞的Holling Ⅲ类功能性反应捕食系统的稳定性分析

研究了一类具有非线性扩散和HollingⅢ类功能性反应且同时具有连续时滞和离散时滞的非自治捕食竞争系统.运用比较定理,得到系统一致持久生存的充分条件.利用Liapunov稳定性理论,得到相应周期系统正周期解存在唯一及全局渐近稳定的充分条件.最后,通过数值模拟来验证结论的正确性.     

一类不确定非线性系统的串级主动补偿控制

针对一类具有下三角结构的单输入单输出不确定非线性系统,研究其稳定控制问题.提出一种结构简单、收敛速度可控以及抗扰性能良好的基于Backstepping方法的串级主动补偿控制策略,实现了闭环系统的渐近稳定控制.为解决闭环系统中不确定非线性未知问题,设计一种新的观测器,使得这种观测器能够实时跟踪闭环系统的不确定非线性.通过引入奇异扰动性理论,给出了闭环系统稳定性分析.仿真实验结果验证了该控制方法的有效性.     

基于CMAC神经网络的一类SISO非线性系统的自适应反馈 …

在已知名义系统的基础上,将ＣＡＡＣ神经网络用于一类状态反馈疔线性化的单输入单输出（ＳＩＳＯ）连续时间非线性系统的鲁棒自适应反馈线性化。使系统获得要求的跟踪性能,控制器的结构为自适应反馈线性化控制律加一个鲁棒控制项,在很弱的假设条件下,应用李雅普诺夫稳定性理论证明了闭环系统内的所有信号为ＵＵＢ（均匀最终有界）。本文衍特别适合于已知名义系统模型但具有不确定性的一类非线性系统的实时控制。仿真算例进一步证     

仿射非线性系统的在线自适应模糊神经网络辨识与控制

针对单输入单输出非线性系统的自适应控制问题,提出了一种在线自适应模糊神经网络辨识与鲁棒控制的方法.该方法首先利用广义模糊神经网络学习算法,实时建立对象模型未知系统的逆动态模型,实现网络结构和参数的同时在线自适应.考虑到网络建模误差和外部干扰的存在,还设计了基于控制理论的鲁棒补偿器.仿真结果表明,该方法能对模型未知仿射非线性系统实现鲁棒输出跟踪.     

基于CMAC神经网络的一类SISO非线性系统的自适应反馈线性化控制

在已知名义系统的基础上,将ＣＭＡＣ神经网络用于一类状态反馈可线性化的单输入单输出（ＳＩＳＯ）连续时间非线性系统的鲁棒自适应反馈线性化,使系统获得要求的跟踪性能,控制器的结构为自适应反馈线性化控制律加一个鲁棒控制项,在很弱的假设条件下,应用李雅普诺夫稳定性理论证明了闭环系统内的所有信号为ＵＵＢ（均匀最终有界）．本方法特别适合于已知名义系统模型但具有不确定性的一类非线性系统的实时控制。仿真算例进一步证明了本方法的正确与有效。     

两类异质混沌系统的同步研究

混沌系统的同步问题是非线性科学的研究热点问题之一.本文利用不连续动力系统理论研究了具有非线性控制约束的单摆系统与陀螺仪系统间的同步问题,给出了两个系统保持完全同步的条件,并通过建立同步开始或消失的转换条件,进一步讨论了两个系统的部分时间同步状态.最后通过数值模拟说明结论的有效性.     

钢与高强混凝土连续组合梁连接件的布置方式

采用ANSYS通用有限元软件,针对钢与高强混凝土连续组合梁本身结构及受力性能的复杂性,考虑材料非线性,提出了一个对钢与高强混凝土连续组合梁从加载到破坏的全过程非线性分析模式,对钢与高强混凝土连续组合梁连接件设计进行分析.研究连接件的布置方式对连续组合梁的影响,完善钢与高强混凝土连续组合梁中抗剪连接件的设计理论.     

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