Modal synthesis of multivariable systems with observers of specified order

The problem of pole assignment in multivariable linear systems with observers of a given order v is considered. By way of a simple proof, a very general result is established which constitutes an extension of all theorems known in the literature on pole assignment via observers. On its basis, an efficient design algorithm is worked out.     

基于内容的差错控制方法研究与实现

视频在传输过程中会因为信道噪声等原因导致失真,采取差错控制方可以保证视频传输的质量.传统的差错控制方法将视频当成普通的比特流,而忽视了视频的内容特征.提出的基于内容的差错控制方法按照内容特征划分视频结构单元并分配相应的差错控制方法.实验结果表明,该差错恢复方法不仅能有效利用信道带宽,而且可保护显著性区域,使重建的视频更加符合用户的视觉需求,实现用小的代价保护重要的视频内容.     

Harmonic Analysis and Loss Comparison of Microcomputer-Based PWM Strategies for Induction Motor Drive

The results presented in this paper were specially chosen to provide a comparative basis for assessing the performance of induction motor drive operating on PWM strategies that have been suitably modified to facilitate real-time implementation using microcomputers. The comparison is made for harmonic copper loss with and without skin effect, end leakage losses, and stray load losses. The simulation results confirm that for low speed operation, Selective Harmonic Elimination (SHE) Technique is unsuited. The regular sampled strategies, in general, are superior to harmonic elimination technique in low and mid frequency range, and associated harmonic losses could be as low as one fourth of the losses occurring with SHE strategies. Sensitivity of the optimal regular sampled strategies for relative phase shift is also investigated. Reduction of 6% in harmonic copper losses occurs for phase shift of 180 at modulation depth of 1.2. teaching tool, and its open architecture would permit the expansion to customize specific requirements. More importantly, users can get     

Effect of pipe orientation on dense-phase transport in inclined upward and downward flows

A physical model is presented to describe the flow characteristics of cocurrent two-layer upflow and downflow through inclined tubes. The influence of inclination angle on these two kinds of flow patterns has been investigated. For inclined upflow, the solids/gas velocity ratio is less than unity and decreases slightly with the increase of inclination angle, whereas for inclined downflow, this velocity ratio is, in general, greater than unity and increases with the inclination angle. The average voidage increases as the inclination angle decreases for inclined upflow while an opposite trend exists for inclined downflow. The pressure gradient is invariably negative for inclined upflow at various inclination angles and for inclined downflow of low inclination; however, the gradient becomes positive for inclined downflow at higher inclination angles. A flow regime map has also been presented. The present predictions agree well with the existing published experimental results.     

Parameters for the attractive coefficient of the patel-teja-valderrama equation of state

A three-parameter form of the temperature dependence of the attractive term in cubic van der Waals type equations of state (AS; Almeida et al., 1991; Aznar and Silva-Telles, 1992) has been applied to a generalized equation of state known as the Patel-Teja-Valderrama equation (PTV; Valderrama, 1990). The parameters of the AS model in the PTV equation of state were calculated for 457 substances of different polarity, molecular size, and chemical nature. The parameters were calculated using vapor pressure data determined through accurate equations available in the literature (Wagner 1973, Antoine 1888, Frost and Kalkwarf, 1953). The deviations between the equation of state calculations and vapor pressure information are lower than 0.5% for most fluids. The study shows that both the generalized PTV cubic equation and the AS represent good tools for pressure-temperature calculations in engineering applications.     

中国古代书院理水中的儒家思想初探

中国古代书院是一种重要的教育组织形式,它除了具有讲学、藏书、祭祀的功能之外,其内部的园林中也体现了士人的寄情山水、崇尚自然、陶冶人格的文化内涵。理水作为中国园林理法中不可或缺的要素,它的运用对于书院园林景象的营造有着重要意义。     

可持续设计策略在建筑几何母题创作中的应用

以基本几何形为母题进行建筑形体和立面设计是一种传统的形态构成方式,可持续性概念是现代主义建筑新思潮下的新思维,两者的良好结合能够使建筑兼备形式美和可持续性。文章剖析了在建筑几何母题创作中可持续设计思想发挥的作用,从几何母题单元和组合两个方面阐释了如何将可持续设计思想融入几何母题创作,进而为可持续建筑设计方法提供新思路。     

一座王府两代帝王：醇亲王府

位于后海北沿的醇亲王府是清朝末期最为显赫的一座王府,先后有光绪、宣统两位皇帝出生于此。新中国成立以来,这里又成为了中华人民共和国荣誉主席宋庆龄的居所,同时也被机关单位占用。因此,规制完整、代表典型的醇亲王府成为了特定历史环境下为数不多保存完好的北京王府之一。本文利用《意见》印发的契机,通过对醇亲王府的选址、沿革、规制的研究,对充分挖掘北京清代王府的历史文化与建筑特色,完整继承北京清代王府的传统文化特色,真正发挥北京清代王府的旅游价值具有重要的现实意义。     

绍兴东浦古镇的景观特色解析

绍兴东浦古镇是历史悠久的水乡集镇,是著名的酒乡、桥乡、名士之乡。本文基于现场的调研,从选址、总体布局、水系和街巷网络、水乡建筑、特色景观节点以及景观序列方面,全面总结了古镇景观特色。该成果有助于对于今天对东浦古镇的保护和利用。     

三峡滨水文物保护规划若干问题的刍议--以瞿塘峡摩崖石刻保护规划为例

三峡滨水文物是历史文化遗产也是长江生态的重要组成部分,对其要采取环境友好型的文物保护策略。本文以瞿塘峡摩崖石刻为例,深入探究在保护区划中,如何应对三峡地区特殊的地理环境、生态保护要求和文物保护要求。希望通过这次个案的经验总结,为三峡滨水文物今后的保护提供参考。