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2009 Asia-Pacific Power and Energy engineering Conference, APPEEC 2009

作者： Yin, Jiacong Xie, Yu Chen, Pu Department of Mechanics and Aerospace Engineering State Key Laboratory for Turbulence and Complex System College of Engineering Beijing 100871 China

ISBN: (纸本)9781424424870

The composite blades of wind turbines are made up of composite shell components. However, blades are often simplified as Eulerian beam in finite element analysis. In design both special and general purpose finite element codes are used worldwide. The verification of a special finite element code BModes vs. a popular general purpose finite element code ANSYS are performed via a uniform blade in both still and spinning cases in this paper. The test reveals that general finite element codes like ANSYS might overestimate the lag frequencies in spinning case. After verification of beam model, the approach is applied to complete the modal analysis of a practical wind turbine blade. The results are compared with a known shell model from literature. The comparison validates the simplified Eulerian beam model. Finally a guideline of usage for these two models is given. © 2009 IEEE.

关键词： Modal analysis

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ROBUSTNESS ANALYSIS OF LEADER-FOLLOWER CONSENSUS

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Journal of systems Science & complexity 2009年第2期22卷 186-206页

作者： Jinzhi WANG Ying TAN · Iven MAREELS State Key Laboratory for Turbulence and Complex System and Department of Mechanics and Aerospace Engi-neering College of Engineering Peking University Beijing 100871 China. Departmen~ of Electrical and Electronic Engineering University of Melbourne Melbourne VIC. 3010 Aus-tralia.

In this paper,robustness properties of the leader-follower consensus are *** of presentation,the attention is focused on a group of continuous-time first-order dynamicagents with a time-invariant communication topology in the presence of communication *** orderto evaluate the robustness of leader-follower consensus,two robustness measures are proposed:the L_2gain of the error vector to the state of the network and the worst case L_2 gain at a *** L_2 gain of the error vector to the state of the network is widely used in robust control design andanalysis,the worst case L_2 gain at a node is less conservative with respect to the number of nodes inthe *** is thus suggested that the worst case L_2 gain at a node is used when the robustnessof consensus is *** analysis and simulation results show that these two measuresare sensitive to the communication *** general,the 'optimal' communication topology thatcan achieve most robust performance with respect to either of the proposed robustness measures isdifficult to characterize and/or *** the in-degree of each follower is one,it is shown thatboth measures reach a minimum when the leader can communicate to each node in the network.

关键词： Communication errors leader-follower consensus robustness.

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NO_x reduction in the sintering process

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 143-148页

作者： Yan-guang Chen Zhan-cheng Guo Zhi Wang Gen-sheng Feng State Key Laboratory of Multiphase Complex System Institute of Process Engineering Chinese Academy Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of the Ministry of Education of China for Recycling ＆ Ecologic Metallurgy University of Science and Technology Beijing Beijing 100083China

A new process, NOx reduction with recycling flue gas and modifying coke breeze, was proposed. The effects of modified coke breeze and recycled flue gas on NOx reduction were investigated by sinter pot tests. The results show that the NOx reduction rate is over 10wt% in the sintering of modified coke breeze, the effects of the additives on NOx reduction are： CeO2〉CaO〉K2CO3. The NOx reduction rate increases with the amount of recycled flue gas, and is 22.35wt% in the sintering with recycling 30vol% of the flue gas. When 30vol% of the flue gas is recycled into the sintering of CeO2, CaO, and K2CO3 modified coke breeze, the NOx reduction rates are 36.10wt%, 32.56wt%, and 32.17wt%, respectively.

关键词： nitrogen oxide flue gas coke breeze cerium oxide sintering

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Characteristics of pyrolytic topping in fluidized bed for different volatile coals

Characteristics of pyrolytic topping in fluidized bed for di...

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20th International Conference on Fluidized Bed Combustion

作者： Xiong, R. Dong, L. Xu, G.W. State Key Laboratory of Multi-Phase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China

Coal is generally combusted or gasified directly to destroy completely the chemical structures, such as aromatic rings containing in volatile coals including bituminite and lignite. Coal topping refers to a process that extracts chemicals with aromatic rings from such volatile coals in advance of combustion or gasification and thereby takes advantage of the value of coal as a kind of chemical structure resource. CFB boiler is the coal utilization facility that can be easily retrofitted to implement coal topping. A critical issue for performing coal topping is the choice of the pyrolytic reactor that can be different types. The present study concerns fluidized bed reactor that has rarely been tested for use in coal topping. Two different types of coals, one being Xiaolongtan (XLT) lignite and the other Shanxi (SX) bituminous, were tested to clarify the yield and composition of pyrolysis liquid and gas under conditions simulating actual operations. The results showed that XLT lignite coals had the maximum tar yield in 823-873K and SX bituminite realized its highest tar yield in 873∼923K. Overall, lignite produced lower tar yield than bituminous coal. The pyrolysis gas from lignite coals contained more CO and CO2 and less CH4, H2 and C2+C 3 (C2H4, C2H6, C 3H6, C3H8) components comparing to that from bituminous coal. TG-FTIR analysis of tars demonstrated that for different coals there are different amounts of typical chemical species. Using coal ash of CFB boiler, instead of quartz sand, as the fluidized particles decreased the yields of both tar and gas for all the tested coals. Besides, pyrolysis in a reaction atmosphere simulating the pyrolysis gas (instead of N2) resulted also in higher production of pyrolysis liquid.

关键词： Fluidized beds

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Synthesis of Ordered Cubic Periodic Mesoporous Silica with High Hydrothermal Stability

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Chemical Research in Chinese Universities 2009年第5期25卷 773-774页

作者： LAI Xiao-yong TU Jin-chun WANG Hong DU Jiang YANG Mei MAO Dan XING Chao-jian WANG Dan LI Xiao-tian College of Materials Science and Engineering Jilin University Changchun 130012 P. R. China State Key Laboratory of Multi-phase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 P. R. China

1 Introduction Since its first discovery in 1992, ordered mesoporous silica material with large pore size, high surface area, and high pore volume has attracted great attention for the potentially wide application in catalysis, adsorption, separation, and ion exchange, etc. However, the poor hydrothermal stability of mesoporous silica has limited its wide application in industry. Therefore, in the last 10 years, many studies have been dedicated to improving the hydrothermal stability of mesoporous silica. Xiao et al.

关键词： Mesoporous silica Hydrothermal stability Nanocasting Ia3d cubic structure

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Theoretical mean-variance relationship of IP network traffic based on ON/OFF model

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Science in China(Series F) 2009年第4期52卷 645-655页

作者： JIN Yi ZHOU Gang JIANG DongChen YUAN Shuai WANG LiLi CAO JianTing State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China School of Computer Science & Engineering Beihang University Beijing 100191 China National Digital Switching System Engineering & Technological Research Center Zhengzhou 450002 China

Mean-variance relationship （MVR）, nowadays agreed in power law form, is an important function. It is currently used by traffic matrix estimation as a basic statistical assumption. Because all the existing papers obtain MVR only through empirical ways, they cannot provide theoretical support to power law MVR or the definition of its power exponent. Furthermore, because of the lack of theoretical model, all traffic matrix estimation methods based on MVR have not been theoretically supported yet. By observing both our laboratory and campus network for more than one year, we find that such an empirical MVR is not sufficient to describe actual network traffic. In this paper, we derive a theoretical MVR from ON/OFF model. Then we prove that current empirical power law MVR is generally reasonable by the fact that it is an approximate form of theoretical MVR under specific precondition, which can theoretically support those traffic matrix estimation algorithms of using MVR. Through verifying our MVR by actual observation and public DECPKT traces, we verify that our theoretical MVR is valid and more capable of describing actual network traffic than power law MVR.

关键词： traffic matrix mean-variance relationship self-similar

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Equality detection for linear arithmetic constraints

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2009年第12期10卷 1784-1789页

作者： Li LI Kai-duo HE Ming GU Xiao-yu SONG Department of Computer Science and Technology Tsinghua University Beijing 100084 China School of Software Tsinghua University Beijing 100084 China MOE Key Laboratory for Information System Security Beijing 100084 China Department of Electrical and Computer Engineering Portland State University Oregon 97207 USA

Satisfiability modulo theories (SMT) play a key role in verification applications. A crucial SMT problem is to combine separate theory solvers for the union of theories. In previous work, the simplex method is used to determine the solvability of constraint systems and the equalities implied by constraint systems are detected by a multitude of applications of the dual simplex method. We present an effective simplex tableau-based method to identify all implicit equalities such that the simplex method is harnessed to an irreducible minimum. Experimental results show that the method is feasible and effective.

关键词： Model checking Satisfiability modulo theories （SMT） Linear arithmetic

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Process analysis of lignite circulating fluidized bed boiler coupled with pyrolysis topping

Process analysis of lignite circulating fluidized bed boiler...

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20th International Conference on Fluidized Bed Combustion

作者： Wang, Baoqun Dong, Li Wang, Yin Matsuzawa, Y. Xu, Guangwen State Key Laboratory of Multiphase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing China Research Laboratory IHI Corporation Ltd. Yokohama Japan

We developed a comprehensive process model in ASPEN Plus to simulate the energy and mass balances of a lignite-fueled atmospheric circulating fluidized bed (CFB) boiler integrated with coal predrying and pyrolysis topping. In this model, it is assumed that the heat from exhausted flue gas was employed for coal predrying, and the sensible heat derived from circulated bed material was used for the pyrolysis topping (endothermic process). The simulation was conducted with respect to the Yunnan Kaiyuan CFB boiler, and two representative lignite coals from Xiao Long Tan (XLT) and Xin Shao (XS) were considered. The result shows that the predrying of coal with the sensible heat of above 363 K from flue gas, the amount of coal consumed in the boiler can be reduced by 3.5% and 5.3% for XLT lignite and XS lignite, respectively. It was also found that integration of pyrolysis topping with the boiler increased the coal consumption of the boiler, and the extent of consumption-increase varies with the yields of tar and gas in the pyrolysis topping process. For a gas yield of 5.2% and a tar yield of 5-6%, the consumption of XS lignite increased by about 20% comparing to that in the case without topping.

关键词： Pyrolysis

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Preparation and Photocatalytic Property of Porous TiO_2 Film with Net-like Framework

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Chemical Research in Chinese Universities 2009年第1期25卷 95-97页

作者： XU Rong-guo YAO Jian-xi LAI Xiao-yong MAO Dan XING Chao-jian WANG Dan State Key Laboratory of Multi-phase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 P. R. China Graduate University of Chinese Academy of Sciences Beijing 100049 P. R. China

By the UV-curing method, a porous TiO2 film with net-like framework has been prepared. The characterization results of the porous TiO2 film by means of SEM, TEM, XRD, and N2 adsorption-desorption analysis show that the net-like framework of the porous TiO2 film is composed of TiO2 nanoparticles, forming three dimensional porous structure. The porous TiO2 film exhibits higher photocatalytic activity for the degradation of methylene blue（MB） dye compared with the conventional dense TiO2 film.

关键词： UV-curing TiO2 Porous film Photocatalytic activity

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High bandwidth real-time network traffic generation with self-similarity

High bandwidth real-time network traffic generation with sel...

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2009 International Conference on Computational Intelligence and software engineering, CiSE 2009

作者： Yuan, Shuai Zhou, Gang Jin, Yi State Key Laboratory of Software Development Environment Beihang University Beijing China National Digital Switching System Engineering and Technological Research Center Information Engineering University Zhengzhou China

ISBN: (纸本)9781424445073

Network traffic generation has always been a hot spot in network measurement and simulation research. However, traditional methods of generating network traffic are either insufficient in fulfilling bandwidth requirement or matching the characteristics of a real network. In this paper we propose a platform of generating high bandwidth real-time network traffic with self-similarity characteristic. The high bandwidth real-time generating feature guarantees the feasibility and self-similarity characteristic makes the platform more reliable. In the platform, we choose Cavium OCTEON CN3860 as the core and implemented ON/OFF aggregation model in a discrete-event way. The Hurst parameter of synthetic traffic is estimated both by R/S statistics method and wavelet estimator. Although there are differences between two estimators in various kinds of conditions, the validation of the platform is empirically discussed and proved. ©2009 IEEE.

关键词： Bandwidth

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