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多模式网络化控制系统稳定性分析

控制理论与应用 2006年第5期23卷 749-755页

作者：郑刚谭民 SONG y H 中国科学院软件研究所通用软件实验室北京100080 中国科学院自动化研究所北京100080 布鲁内尔大学电子与计算机工程系英国伦敦

网络传输引起的时滞在网络化控制系统中经常出现．针对存在多个运动模式的网络化控制系统,建立了时滞混杂自动机模型,分析了系统平衡点的稳定性,给出了平衡点保持稳定的充分条件在于构造的与离散状态相关的Lyapunov泛函在离散状态的切... 详细信息

网络传输引起的时滞在网络化控制系统中经常出现．针对存在多个运动模式的网络化控制系统,建立了时滞混杂自动机模型,分析了系统平衡点的稳定性,给出了平衡点保持稳定的充分条件在于构造的与离散状态相关的Lyapunov泛函在离散状态的切换时刻是非增的．当时滞混杂自动机中连续性子系统为线性时不变时滞系统时,可以利用线性矩阵不等式方法来寻找系统的公共Lyapunov泛函,并求解使系统平衡点保持稳定的时滞上界．最后,给出了一个例子说明了分析结果．

关键词：网络控制混杂系统稳定性时滞系统线性矩阵不等式

A dynamic solution for predicting resonant frequency of piston mode fluid oscillation in moonpools/narrow gaps

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Journal of Hydrodynamics 2020年第1期32卷 54-69页

作者： Lei tan Lin Lu Guo-qiang tang Liang Cheng State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China International Joint Laboratory on Offshore Oil and Gas Engineering Dalian University of TechnologyDalian 116024China School of Engineering The University of Western AustraliaPerthAustralia

The objective of this study is to develop a simple tool for predicting the resonant frequency of the piston mode wave oscillation in a moonpool or a narrow gap between twin floating *** on the dynamic analysis and the domain-decomposition,a linear harmonic oscillator model for the fluid oscillation in a confined space is formulated,which immediately leads to an explicit dynamic solution for the resonant *** the model,it is assumed that the water depth is equal to or greater than a critical value dependent on the ratio of the draft to the breadth of the floating *** predicted resonant frequencies are compared with the numerical results of the linear potential model and the viscous fluid model,the semi-analytical potential solutions and the experimental *** agreements are observed for a wide range of geometric parameters of the moonpool and the narrow gap of either sharp or round edge *** present dynamic method is also applied to predict the resonant frequency of the piston mode oscillation in the gap between a floating body and a vertical wall with a reasonable success.

关键词： Resonant frequency piston mode resonance moonpool narrow gap dynamic model

Risk Prediction of Aortic Dissection Operation Based on Boosting Trees

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Computers, Materials & Continua 2021年第11期69卷 2583-2598页

作者： Ling tan yun tan Jiaohua Qin Hao tang Xuyu Xiang Dongshu Xie Neal N.Xiong The Second Xiangya Hospital of Central South University Changsha410011HunanChina Central South University of Forestry&Technology Changsha410004HunanChina Northeastern State University Tahlequah74464OKUSA

During the COVID-19 pandemic,the treatment of aortic dissection has faced additional *** necessary medical resources are in serious shortage,and the preoperative waiting time has been significantly prolonged due to the requirement to test for COVID-19 *** this work,we focus on the risk prediction of aortic dissection surgery under the influence of the COVID-19 pandemic.A general scheme of medical data processing is proposed,which includes five modules,namely problem definition,data preprocessing,data mining,result analysis,and knowledge *** on effective data preprocessing,feature analysis and boosting trees,our proposed fusion decision model can obtain 100%accuracy for early postoperative mortality prediction,which outperforms machine learning methods based on a single model such as LightGBM,XGBoost,and *** results reveal the critical factors related to the postoperative mortality of aortic dissection,which can provide a theoretical basis for the formulation of clinical operation plans and help to effectively avoid risks in advance.

关键词： Risk prediction aortic dissection COVID-19 postoperative mortality boosting tree

STABLE PROGRAMMED MANIFOLD SOLVER FOR VIRTUAL PROTOTyPING MOTION SIMULATION

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Chinese Journal of Mechanical Engineering 2006年第1期19卷 76-80页

作者： tan Jianrong WANG Zheng LIU Zhenyu State Key Laboratory of CAD＆CG Zhejiang University Hangzhou 310027 China

Based on constructing programmed constraint and constraint perturbation equation, a kinematics and dynamics numerical simulation model is established for virtual mechanism, in which the difference scheme guarantee precision in simulation procedure and its mtmerical solutions satisfy programmed manifold stability. A crank-piston mechanism in a car engine, a steering mechanism and a suspension mechanism are simulated in a virtual environment, then comparing the simulation results with those obtained in ADAMS under the same circumstances proved the solver valid.

关键词： Kinematics Dynamics Constraint Differential-algebraic equation

Synthesis and characterization of SrCe_(0.95)y_(0.05)O_(3-δ) nano powders by low temperature combustion

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Rare Metals 2006年第1期25卷 79-83页

作者： MENG Bo tan Xiaoyao ZHANG Baoyan yANG Naitao College of Chemical Engineering and Technology Shandong University of Technology Zibo 255049 China College of Science Northeastern University Shenyang 110004 China

Nanosized SrCe0.95y0.05O3-δ powders with homogeneous composition were synthesized by the low temperature combustion process based on the Pechini method. A polymeric precursor sol was formed by using citric acid and ethylene glycol as the chelating agents of metal ions. The perovskite-type SrCe0.95y0.05O3-δpowders with uniform shape and smaller than 25 nm in size were obtained through the combustion of the polymeric precursor sol at the existence of nitric acid and ammonium hydroxide. It was found that modulating the quantifies of nitric acid and ammonium hydroxide could control the particle size, and the quantities of residue carbonate ions were also affected by the quantifies of citric acid and ethylene glycol.

关键词： inorganic nonmetal material perovskite-type oxides SrCe0.95y0.05O3-δ combustion synthesis

Dominance network structure across reproductive contexts in the cooperatively breeding cichlid fish Neolamprologus pulcher

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Current Zoology 2015年第1期61卷 45-54页

作者： Cody J. DEy Q.y. Joanne tan Constance M. O'CONNOR Adam R. REDDON J. Ryan CALDWELL Sigal BALSHINE Department of Biology McMaster University Hamilton Ontario ON L8S 4K1 Canada Department of Psychology Neuroscience and Behaviour McMaster University Hamilton Ontario L8S 4L8 Canada

While a large number of studies have described animal social networks, we have a poor understanding of how these networks vary with ecological and social conditions. For example, reproductive periods are an important life-history stage that may involve changes in dominance relationships among individuals, yet no study to date has compared social networks of do- minance interactions （i.e. dominance networks） across reproductive contexts. We first analyzed a long-term dataset on captive so- cial groups of the cooperatively breeding cichlid Neolamprologuspulcher, and found that eviction events were significantly more common around reproduction than expected by chance. Next, we compared the structure of dominance networks during early pa- rental care and non-reproductive periods, using one of the first applications of exponential random graph models in behavioral biology. Contrary to our predictions, we found that dominance networks showed few changes between early parental care and non-reproductive periods. We found no evidence that dominance interactions became more skewed towards larger individuals, became more frequent between similar-sized individuals, or became more biased towards a particular sex during parental care. However, we did find that there were relatively more dominance interactions between opposite-sex dyads in the early parental care period, which may be a by-product of increased sexual interactions during this time. This is the first study in behavioral ecology to compare social networks using exponential random graph modeling, and demonstrates a powerful analytical framework for future studies in the field [Current Zoology 61 （1）： 45-54, 2015].

关键词： Social network Aggression Submissive Hierarchy Parental care P* model

High Preformation SiC-AlN Composites

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Journal of Materials Science & Technology 1997年第4期13卷 342-344页

作者： Chen, ZM tan, SH Zhang, ZQ Jiang, DL Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

High performance SiC-AlN composites were fabricated by hot-pressing with y2O3 as additive via liquid phase sintering. The SiC-AlN composites containing 5 vol. pet AIN exhibit superior mechanical properties with flexural strength, fracture toughness and Vickers hardness of 1131 MPa, 6.1 MPa.m(1/2) and 28.6 GPa respectively. Microstructure observations indicate that the grain size of the composites is obviously inhibited due to the formation of solid solution. TEM-EDS analysis demonstrates the existence of the solid solution. In addition, subgrain boundaries induced by dislocations in the matrix SiC grains, seem to divide a large grain into numerous nano-sized small grains, which significantly increase the mechanical properties of the composites.

关键词： Ceramic matrix composites

Imidodiphosphorimidates (IDPis): Catalyst Motifs with Unprecedented Reactivity and Selectivity

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Chinese Journal of Chemistry 2023年第6期41卷 685-694页

作者： Jun Kee Cheng Shao-Hua Xiang Bin tan Shenzhen Grubbs Institute and Department of Chemistry Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhenGuangdong 518055China Academy for Advanced Interdisciplinary Studies Southern University of Science and TechnologyShenzhenGuangdong 518055China

The conceptually designed imidodiphosphorimidates(IDPis)have emerged as one of the most potent classes of chiral acid *** are characterized by enzyme-like,highly confined active site and high acidity,which underlie their wide-reaching applications as Bronsted acid catalysts and as precatalysts for silylium Lewis *** carbon-carbon and carbon-heteroatom bond formation reactions that were deemed intractable could now be attained with spectacular reactivity and *** that are small,unbiased and/or possess insufficient reactivity such as simple alkenes could now be *** high structural confinement is particularly invaluable to control stereo-and *** well-defined steric environment offers unique opportunity to control high-energy but structurally unbiased cation intermediates such as the norbonyl *** practical appeals such as good scalability as well as ease and modularity of preparation,the extremely low pre-catalyst loadings required to achieve high turnover and stereoselectivity have also come to define a new frontier in organocatalysis.

关键词： Bronsted acid catalyst Lewis acid catalyst Silylium ACDC Imidodiphosphorimidates Asymmetric organocatalysis

Effect of neodymium and yttrium addition on microstructure and DC soft magnetic property of dual-phase FeCoNi(CuAl)_(0.8)high-entropy alloy

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Journal of Rare Earths 2023年第10期41卷 1562-1567,I0004页

作者： Jiaxin Zhu Mengxin Lv Chang Liu Xiaohua tan Hui Xu Institute of Materials School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

The correlation between the microstructure and soft magnetic properties under the direct current(DC)mode of dual-phase FeCoNi(CuAl)_(0.8)RE_(0.05)(RE=Nd,y)high-entropy alloys(HEAs)was *** diffraction(XRD)and electron backscattered diffraction(EBSD)results show that all samples consist of face-centered cubic(FCC)and body-centered cubic(BCC)*** comparison to the volume fraction of BCC phase of the RE-free HEA(25.3%),Nd and y additions dramatically increase it to 42.0%and 43.3%,which leads to an increase of the saturation *** addition reduces the average grain size from 7.26 wm of the RE-free HEA to 5.42μm of RE=Nd HEA and 4.88μm of RE=y *** magnetic domain structure is observed in both FCC and BCC phases in the RE-free and RE-containing *** additives of Nd and y both decrease the stripe pattern width in FCC and BCC *** refined structure and finely spaced stripe domain by RE addition can decrease the *** with the RE-free HEA,RE addition can effectively enhance the DC soft magnetic property by decreasing the remanence,the coercivity,and the hysteresis loss.

关键词： Dual-phase high-entropy alloy Rare earths Soft magnetic property Stripe domain structure