不确定系统的动态输出反馈镇定

研究一类单输入单输出非线性不确定系统的动态输出反馈镇定，当系统的确定性部分为最小相位系统时，提出一种构造动态补偿器的新方法。与先前有关结果比较，该动态２补偿器能适应更广类型的不确定性。     

不确定关联时滞系统基于观测器的鲁棒分散镇定

讨论了一类不确定关联时滞系统基于状态观测器的鲁棒分散镇定问题·系统的不确定性是未知时变且范数有界的,系统状态及控制输入、互联项中均存在时滞·根据李亚普诺夫稳定性理论,给出了系统可分散输出反馈镇定的充分条件,即一组线性矩阵不等式(LMI)有解·所设计的分散控制器保证系统渐进稳定·仿真结果表明,该方法是有效的·     

确定线性动态控制系统的鲁棒性设计方法

鲁棒线性控制器设计的主要问题是针对对象模型不确定性,寻找线性反馈控制器,使得不确定控制系统稳定。针对具有线性、非线性或时变结构的模型不确定性多变量动态系统,采用动态补偿器结构与原系统进行增广,构成闭环动态近似系统,根据Gronwall引理,推导出了基于不 确定性范数上界的动态线性系统鲁棒稳定的充分条件。根据鲁棒稳定条件,给出了具体的动态不确定系统的鲁棒性设计算法。通过选择适当的变换阵,利用特征值配置技术求出动态补偿器的参数,来满足鲁棒稳定条件,使得闭环不确定动态系统稳定,从而提出了一种时域内鲁棒线性 控制器设计方法－动态补偿器法。该方法同样适用于控制器为输出反馈的情形,给出了具体设计实例,以验证设计方法的简单性与有效性。     

不确定时滞线性系统的鲁棒镇定问题

针对过程控制中普遍存在的时滞和不确定现象,应用Lyapunov稳定方法和Riccati方程方法研究了存在滞后的不确定线性系统的鲁棒镇定问题,其中的不确定性是时变有界的,不要求满足“匹配条件”;获得了一类不确定线性时滞系统用状态反馈控制器进行鲁棒镇定的充分条件.该充分条件以线性矩阵等式存在对称正定解的形式给出,通过求解代数Riccati方程的对称正定解构造线性状态反馈稳定化控制器.最后给出了算例,结果证明了对于不确定线性时滞系统,应用该方法构造的线性状态反馈稳定化控制器,可使闭环系统渐近稳定.     

具有α-稳定性的线性不确定时滞系统鲁棒镇定

研究了一类具有时变状态时滞和参数不确定性的线性不确定时滞系统的鲁棒α镇定问题.基于线性矩阵不等式(LMI)方法,提出了依赖于时滞大小的鲁棒α稳定判据和状态反馈鲁棒α镇定控制律存在的充分条件及相应的控制器设计方法.数值算例验证了所给结果的有效性.     

不确定中立型系统输出反馈H∞控制

考虑一类含有参数不确定性的混合型中立型系统的输出反馈控制器设计问题·不确定性假设是时变的但范数有界,状态时滞是常数·利用线性矩阵不等式方法和Lyapunov函数方法相结合,研究了输出反馈鲁棒控制器的设计问题·目的是设计一个动态输出反馈控制器,使得在满足一定的条件下对所有的参数不确定性,闭环系统是渐近稳定的且从扰动到控制输出的传递函数的范数是不超过某个确定的上界,并给出了动态输出反馈控制器存在的充分条件·所得结论可化为标准的LMIs求解,具有一定的实际意义和可行性·     

一类不确定线性切换系统的鲁棒镇定

研究了一类不确定线性切换系统基于状态反馈的鲁棒镇定问题.此类切换系统不仅具有未知时变但有界的结构不确定性,还具有不满足匹配条件的外部扰动.首先利用完备性条件与共同李亚谱诺夫函数方法,在各子系统不需满足镇定的条件下,设计了切换系统的状态反馈鲁棒控制器及相应的切换策略,使不确定线性切换系统的状态在其平衡点处渐近稳定,得到了切换系统可状态反馈镇定的充分条件;然后基于凸组合技术与线性矩阵不等式方法,将所得结果用易于求解的线性矩阵不等式的形式表出;最后通过仿真例子表明所设计的状态反馈控制器在给定的切换策略下,可使不确定切换系统的状态达到渐近稳定.     

经由控制器切换下的不确定时滞系统的鲁棒控制

研究了一类基于控制器切换下的不确定系统的鲁棒镇定问题．假设系统存在有限个备选的静态状态反馈控制器，在每个备选的控制器均不能镇定系统的情况下，针对状态矩阵、控制输入矩阵及状态时滞部分同时带有参数不确定性的系统，利用凸组合条件设计出相应的切换策略，经由控制器切换得到了不确定系统镇定的一个充分条件，并且此条件可转化为求解线性矩阵不等式（LMI）问题．最后仿真结果表明所设计切换策略的正确有效性．     

不确定系统的输出反馈鲁棒正实优化设计

讨论了系数矩阵具有有界范数不确定性系统的输出反馈鲁棒严格正实设计问题。基于不确定系统二次扩展严格正实的概念,利用线性矩阵不等式方法,得到了不确定系统存在动态输出反馈控制使得闭环系统二次扩展严格正实的充要条件,并进一步给出了正实控制器的设计方法。     

不确定系统的输出反馈鲁棒正实优化设计

讨论了系数矩阵具有有界范数不确定性系统的输出反馈鲁棒严格正实设计问题。基于不确定系统二次扩展严格正实的概念，利用线性矩阵不等式方法，得到了不确定系统存在动态输出反馈控制使得闭环系统二次扩展严格正实的充要条件，并进一步给出了正实控制器的设计方法。     

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.     

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.     

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.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.