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A family of robust adaptive excitation controllers for synchronous generators with steam valve via Hamiltonian function method

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控制理论与应用（英文版） 2012年第1期10卷 11-18页

作者： song xu Xiaorong HOU School of Automation Engineering University of Electronic Science and Technology of China Chengdu Sichuan 611731 China Faculty of Science Ningbo University Ningbo Zhejiang 315211 China

Using the Hamiltonian function method, this paper proposes a family of robust adaptive excitation con- trollers for synchronous generators with steam valve control. First, a parameterization method of robust adaptive controllers is investigated for dissipative Hamiltonian systems. This method avoids solving Hamilton-Jacobi-Issacs inequalities. The parameters in the family of controllers thus obtained are determined by a locally positive semidefinite function, which has only 2n independent variables, twice as many as the one used to characterize the state feedback. Then, with the parame- terization method and the structural properties of dissipative Hamiltonian systems, a family of robust adaptive excitation controllers is designed for synchronous generators with steam valve control, disturbances and unknown parameters. Simu- lations illustrate the effectiveness and feasibility of the excitation control strategy proposed in the paper.

关键词： Pararneterization Robust adaptive controller Synchronous generator Steam valve control Hamiltonianfunction method

CO_(2)-Induced Modulation of Si-O Bonds for Low Temperature Plastic Deformation of Amorphous Silica Nanoparticles with Enhanced Photoluminescence

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Energy & Environmental Materials 2024年第4期7卷 404-412页

作者： Kang Huang Wenzhuo Wu song xu Pengfei Yan Zhongming Wei Qun xu Henan Institute of Advanced Technology Zhengzhou UniversityZhengzhou 450001China College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China

Modulation of Si-O bonds under mild conditions has been a challenging issue in the field of material science,which is critical to manufacture highperformance silica-based optical and photonic ***,we introduce a nondestructive technique to achieve Si-O bond rearrangement,leading to plastic deformation and photoluminescence enhancement of amorphous silica nanoparticles using supercritical carbon dioxides in EtOH/H_(2)O solution under mild ***,plastic deformation is achieved by treating hollow mesoporous silica nanospheres using supercritical CO_(2)at 40°C under 20 *** and theoretical studies revealed the critical role of supercritical CO_(2)in the plastic deformation process,which can be intercalated into the hollow mesoporous silica nanospheres with anisotropic stresses and induces the rearrangement of Si-O bonds and transformation of ring *** work suggests a novel approach to engineer high-performance nano-silica glass components for numerous optical and photonic devices under mild condition.

关键词： amorphous silica anisotropic stress photoluminescence plastic deformation supercritical CO_(2)

A Dynamic Programming Algorithm on Project- Gang Investment Decision Making

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Wuhan University Journal of Natural Sciences 2002年第4期7卷 403-407页

作者： xu xu-song Wu Jian-mou Wuhan University

The investment decision making of Project Gang, the projects that are associated with one another on economy and technique, is studied. In order to find out the best Scheme that can make the maximum profit, a dynamic programming algorithm on the investment decision making of Project Gang is brought forward, and this algorithm can find out the best Scheme of distributing the m resources to the n Items in the time of O(m 2 n).

关键词： Project-Gang investment decision making dynamic programming algorithm

Dynamics of Polymeric Fluids：Part Ⅱ The Molecular Theory of Die Swell： Correlation of Ultimate Die Swelling Effect to the Molecular Parameters and the Operational Variables

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Journal of Materials Science & Technology 2006年第5期22卷 664-676页

作者： Mingshi song Qiang xu Guixian HU Sizhu WU Key Laboratory of Science and Technology of Controlled Chemical Reactions Beijing University of Chemical TechnologyBeijing 100029 China

A general expression for the correlation of the simple shear （tanφ） to the molecular parameters and the shear rate （·↑γ） was deduced. It shows that the simple shear （tanφ） may be resolved into free recoil （recoverable strain） and viscous heating （unrecoverable strain）. The magnitudes of the simple shears for recoil （tanφE） and （tanφv） for viscous heating not only depended on the molecular parameters and the operational variables, but also on the exponential fractions of the recoverable （1--↑W·↑γ） and unrecoverable （-↑W·↑γ） conformations for recoil and viscous heating. Therefore the magnitudes of the simple shears （tanφE） for recoil and （tanφv） for viscous heating are, respectively, expressed as the partition function to the （1--↑W·↑γ）th power and the partition function to the （-↑W·↑γ）th power. Thus correlations of the total recoil and the ultimately recoverable strains to the molecular parameters [n′, α, η0, GN^0 and （1--↑W·↑γ）] and the operational variables （·↑γ, （L/D） and tr） were deduced respectively, which show that at very different shear rates （0≤·↑γ≤∞） the polymeric liquids may exhibit a very different viscoelastic behaviors. After introducing the uniform two-dimensional extension, the definition of swelling ratio and the ratio of L to D [De=（L/D）], two expressions for the ultimate die swelling effect and the ultimate extrudate swelling ratio BEVT5 to the molecular parameters [n′, α, η0, GN^0 and （1--↑W·↑γ）] and the operational variables （·↑γ, （L/D） and tr） were obtained. The two correlation expressions were verified by the experimental data of high-density polyethylene （HDPE） which shows that the two correlation expressions can be used to predict the correlations of the ultimate extrudate swelling behaviors of polymeric liquids to the molecular parameters and the operational variables.

关键词： Die swell Viscoelastic recoil Entanglement

A Family of Adaptive H_∞ Controllers with Full Information for Dissipative Hamiltonian Systems

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International Journal of Automation and computing 2011年第2期8卷 209-214页

作者： song xu Xiao-Rong Hou School of Automation Engineering University of Electronic Science and Technology of China Chengdu 611731 PRC Faculty of Science Ningbo University Ningbo 315211 PRC

This paper investigates a parameterization method of adaptive H∞ controllers for dissipative Hamiltonian systems with disturbances and unknown *** family of adaptive H∞ controllers with full information is obtained by interconnecting an adaptive H∞ controller with a generalized zero-energy-gradient （ZEG） detectable,free generalized Hamiltonian *** present parameterization method avoids solving Hamilton-Jacobi-Issacs equations and thus the controllers obtained are easier in operation as compared to some existing *** show the effectiveness and feasibility of the adaptive control strategy proposed in this paper.

关键词： Parameterization adaptive H∞ controller dissipative Hamiltonian system full information generalized zero-energygradient (ZEG) detectable.

Value of cerebral perfusion and vascular reserve for the treatment of symptomatic intracranial arterial stenosis

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Neural Regeneration Research 2008年第1期3卷 79-82页

作者： Li＇an Huang xuewen song Anding xu Department of Neurology First Affiliated Hospital of Jinan University Guangdong 510632 Guangzhou Province China

BACKGROUND： It is crucial to understand cerebral perfusion and vascular reserve in stegnotic arterial blood-supply regions to treat ischemic cerebrovascular diseases. However, effects on symptomatic intracranial arterial stenosis （SICAS） need to be further studied in additional applications. OBJECTIVE： To evaluate and summarize the effects of cerebral perfusion and vascular reserve on the treatment of SICAS. RETRIEVAL STRATEGY： A computer-based online search of English language publications from January 2000 to July 2007 was conducted in PubMed to identify publications that addressed cerebral perfusion and vascular reserve of SICAS. Search key words were ＂intracranial stenosis, perfusion, brain reserve＂. Relevant data were also searched with the China Journal Net, using the same key words in Chinese from January 2000 to January 2007. In total, 101 articles were retrieved. Inclusion criteria：（1） Articles describing the current status for the diagnosis and treatment of SICAS; （2） Articles concerning research developments of cerebral perfusion and vascular reserve of SICAS. Exclusion criteria： duplicated articles. LITERATURE EVALUATION： This study included 21 articles of experimental studies and conference reports. DATA SYNTHESIS： When performing interventional surgery in SICAS patients, it is important to understand cerebral perfusion and vascular reserve in addition to knowing the clinical symptoms and degrees of arterial stenosis. In recent years, there are a growing number of reports on measurements of vascular reserve through the use of magnetic resonance perfusion imaging （MR-PWI）. Investigations demonstrate cerebral perfusion and vascular reserve decrease in many SICAS patients. Many studies show that both improve after surgical intervention. CONCLUSION： Cerebral perfusion could provide direct evidence of whether ischemia has occurred in the brain. Because of lateral circulation and cerebral vascular reserve, intracranial vascular stenosis and/or decreased intr

关键词： intracranial stenosis perfusion brain reserve

Nonclassical Effects of a Four-Level Excited-Doublet Atom Model

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Communications in Theoretical Physics 2006年第6X期46卷 1069-1073页

作者： ZHANG Jian-song xu Jing-Bo Zhejlang Institute of Modern Physics and Department of Physics Zhejiang University Hangzhou 310027 China

We adopt a dynamical algebraic method to study a four-level excited-doublet atom model and obtain the explicit expressions of the time-evolution operator and the density operator for the system. The nonclassical effects of the system, such as collapses and revivals of the atomic inversion and squeezing of the radiation field, are also discussed.

关键词： atom-field interaction nonclassical effects

Rate allocation strategies for energy-efficient multipath routing in Ad-hoc networks towards B3G

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 84-88页

作者： ZHAN song-tao xu Guo-xin Wireless Technologies Innovation Institute Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Wireless mobile Ad-hoc network is a special network that all nodes can serf-organize and work together. It is flexible to form a network and extend the coverage area dynamically without infrastructure, so Ad-hoc network is envisioned as cornerstones of future generation networking technologies （B3G or 4（3）. However, the dynamic network topology makes the communication cost not only the energy of source/destination nodes, but also the relay nodes. Another problem of the Ad-hoc network is it is hard to provide a stable and persistent quality of service （QoS）, which is strongly required by the beyond 3rd generation （B3G） system. In this article, the authors establish a scenario that contains B3G cellular base station and Ad-hoc mobile nodes, and propose two algorithms minimum incremental rate algorithm and power feed-back rate allocation algorithm in multipath routing. The algorithms can maintain a constant total transmission rate and bit error ratio （BER） to provide the QoS guarantee and reach the minimum power consumption of the relay nodes by adjusting the rate of each path in the multipath routing.

关键词： Ad-hoc network B3G multipath routing energy consumption QoS

Ruthenium catalyzed amination cyclization of 1,2,4-butanetriol with primary amines:A borrowing hydrogen strategy for 3-pyrrolidinol synthesis

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Chinese Chemical Letters 2020年第1期31卷 103-106页

作者： Qing-song xu Chen Li Yong xu Defeng xu Mei-Hua Shen Hua-Dong xu School of Pharmaceutical Engineering & Life Science Changzhou University

A ruthenium based catalytic system([Ru(p-cymene)Cl2]2/XantPhos with substoichiometric Cs2CO3)has been established to effectively achieve the first direct amination cyclization of 1,2,4-butanetriol with primary aromati... 详细信息

关键词： Amination cyclization N-Alkylation 1,2,4-Butanetriol 3-Pyrrolidinol Borrowing hydrogen Hydrogen autotransfer [Ru(p-cymene)Cl2]2