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Dynamics of cantilever plates and its hybrid vibration control

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Acta Mechanica Sinica 2013年第5期29卷 738-748页

作者： Bo Ni chao hu School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai Institute of Spaceflight Fundamental Technology College of Civil Science and Engineering Yangzhou University

Applying Lagrange-Germain＇s theory of elas- tic thin plates and Hamiltonian formulation, the dynamics of cantilever plates and the problem of its vibration control are studied, and a general solution is finally given. Based on Hamiltonian and Lagrangian density function, we can obtain the flexural wave equation of the plate and the relationship between the transverse and the longitudinal eigenvalues. Based on eigenfunction expansion, dispersion equations of propagation mode of cantilever plates are deduced. By satisfying the boundary conditions of cantilever plates, the natural frequencies of the cantilever plate structure can be given. Then, analytic solution of the problem in plate structure is obtained. An hybrid wave/mode control approach, which is based on both independent modal space control and wave control methods, is described and adopted to analyze the active vibration control of cantilever plates. The low-order （controlled by modal control） and the high-order （controlled by wave control） frequency response of plates are both improved. The control spillover is avoided and the robustness of the system is also improved. Finally, simulation results are analyzed and discussed.

关键词： Cantilever plate Hamiltonian formulism - Dis- persion equations Modal control Elastic wave control - Hybrid control

Budget constrained flow interception location model for congested systems

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1255-1262页

作者： hu Dandan Yang chao Yang Jun Dept. of Management Science and Engineering Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

To study location problems with congestion demand, a bi-objective model based on flow intercep-tion problem is *** model is formulated from the view of M/M/m queuing *** quantity and quality are simultaneously considered as objectives, with constraint on total *** quality includes deviation distance from preplanned trips and customers＇ waiting *** quantity is the number of intercep-tion customers.A multi-objective evolutionary algorithm combined with greedy heuristic is *** a computational experiment is given, and the algorithm is proved to be efficient.

关键词： location flow interception bi-objective heuristic.

Model and algorithm of flow interception problem with multi-type of flows

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Journal of Systems Engineering and Electronics 2009年第4期20卷 755-761页

作者： hu Dandan Yang chao Yang Jun Dept. of Management Science and Engineering Huazhong Univ. of Science and Technology Wuhan 430074 P. R. China

To study simultaneous location of different kinds of facilities, a new model of flow interception problem with multi-type of flows is proposed, with the consideration of multi-purpose flows and the influence of facilities on each other. To be more practical, the objective is to maximize the benefits from flow-by customers instead of maximizing flows in the past. Since this problem is NP-hard and there is no optimal solution for large network, greedy and improved greedy heuristic algorithms are proposed. A computational example is presented to show that the optimal location decisions are proved to be strongly dependent on the influence coefficients and average profits by one customer and different types of facilities are almost co-located. Finally the results of sensitivity analysis are reported.

关键词： location flow interception greedy heuristic multi-purpose influence coefficient

Dithieno[a,e]pentalene Based Conjugated Polymers： Synthesis and Characterization

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Chinese Journal of Chemistry 2013年第11期31卷 1404-1408页

作者： chao hu Qing Zhang School of Chemistry and Chemical Engineering Shanghai Jiao Tong University Shanghai 200240 China

The concept of introducing n-conjugated but anti-aromatic repeating units into conjugated polymers has been explored. The thermal stability, optical and electrochemical properties of dithieno[a,e]pentalenes （DTP） based polymers have been studied. The effect of introducing electron withdrawing repeating units into DTP based poly- mer on the physical properties of polymer has also been investigated. The new polymers showed broad absorption in visible and near-infrared region.

关键词： pentalene conjugated polymer low-bandgap polymer anti-aromatic

GPS/CAPS dual-mode software receiver

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Science China(Physics,Mechanics & Astronomy) 2009年第3期52卷 360-367页

作者： NING ChunLin SHI huLi hu chao National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China Graduate University of Chinese Academy of Sciences Beijing 100049China

The positioning of the GPS or Chinese Area Positioning System (CAPS) software receiver was developed on a software receiver platform. The structure of the GPS/CAPS dual-mode software receiver was put forward after analyzing the differences in the satellite identification, ranging code, spread spectrum, coordinate system, time system, carrier band, and navigation data between GPS and CAPS. Based on Matlab software on a personal computer, baseband signal processing and positioning procedures were completed using real GPS and CAPS radio frequency signals received by two antennas. Three kinds of experiments including GPS positioning, CAPS positioning, and GPS/CAPS positioning were carried out. Stability and precision of the results were analyzed and compared. The experimental results show that the precision of CAPS is similar to that of GPS, while the positioning precision of the GPS/CAPS dual-mode software receiver is 1-2 m higher than that of CAPS or GPS. The smallest average variance of the positioning can be obtained by using the GPS/CAPS dual-mode software receiver.

关键词： Chinese area positioning system global navigation satellite system dual-mode software receiver

A Method for Rapidly Determining the Optimal Distribution Locations of GNSS Stations for Orbit and ERP Measurement Based on Map Grid Zooming and Genetic Algorithm

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Computer Modeling in Engineering & Sciences 2018年第12期117卷 509-525页

作者： Qianxin Wang chao hu Ya Mao NASG Key Laboratory of Land Environment and Disaster Monitoring China University of Mining and TechnologyXuzhou221116China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou221116China Mathematical and Geospatial Sciences RMIT UniversityMelbourne 3001Australia.

Designing the optimal distribution of Global Navigation Satellite System(GNSS)ground stations is crucial for determining the satellite orbit,satellite clock and Earth Rotation Parameters(ERP)at a desired precision using a limited number of *** this work,a new criterion for the optimal GNSS station distribution for orbit and ERP determination is proposed,named the minimum Orbit and ERP Dilution of Precision Factor(OEDOP)*** quickly identify the specific station locations for the optimal station distribution on a map,a method for the rapid determination of the selected station locations is developed,which is based on the map grid zooming and heuristic *** the minimum OEDOP criterion and the proposed method for the rapid determination of optimal station locations,an optimal or near-optimal station distribution scheme for 17 newly built BeiDou Navigation Satellite System(BDS)global tracking stations is *** verify the proposed criterion and method,real GNSS data are *** results show that the minimum OEDOP criterion is valid,as the smaller the value of OEDOP,the better the precision of the satellite orbit and ERP *** to the exhaustive method,the proposed method significantly improves the computational efficiency of the optimal station location *** the case of 3 newly built stations,the computational efficiency of the proposed method is 35 times greater than that of the exhaustive *** the number of stations increases,the improvement in the computational efficiency becomes increasingly obvious.

关键词： Global Navigation Satellite System(GNSS) optimal distribution of station network map grid zooming genetic algorithm.

Characteristics on Hydro-mechanical Transmission in Power Shift Process

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 50-56页

作者： hu Jibin WEI chao YUAN Shihua JING Chongbo National Key Laboratory of Vehicular Transmission Beijing Institute of Technology Beijing 100081 China

To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

关键词： stepless transmission hydro-mechanical transmission power shift

A combined continuous-discontinuous approach for failure process of quasi-brittle materials

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Science China(Technological Sciences) 2014年第3期57卷 550-559页

作者： CHANG XiaoLin hu chao ZHOU Wei MA Gang ZHANG chao State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

Rock,concrete and other geo-materials,due to the presence of microstructural inhomogeneity,their fracture processes and damage characteristics are associated with the distribution of micro-cracks contained in the *** this study,by introducing a cohesive zone model based on fracture mechanics into the framework of deformable discrete element method,a continuous-discontinuous coupling analysis approach for simulating the fracture of quasi-brittle materials is *** cohesive interface elements are inserted into certain engineering or research *** is assumed that damage and fracture occur only in the interface elements,while bulk material is modeled to be *** Mohr-Coulomb criterion with tension cut-off is adopted as the damage initiation criterion,and a scalar damage variable representing damage in the material is used to describe the rate at which the material stiffness is *** are simulated explicitly by the failure of the interface *** simulations are performed in order to validate the suggested *** applications are also *** results show that this method provides a simple but effective tool for the simulation of crack initiation and propagation,and it can reflect the whole process of quasi-brittle materials from small deformation to large deformation and failure.

关键词： quasi-brittle materials deformable discrete elements cohesive zone model crack propagation

Wave localization in randomly disordered periodic layered piezoelectric structures

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Acta Mechanica Sinica 2006年第6期22卷 559-567页

作者： Fengming Li Yuesheng Wang chao hu Wenhu huang Department of Aerospace Science and Mechanics Harbin Institute of Technology Harbin 150001 China Institute of Engineering Mechanics Beijing Jiaotong University Beijing 100044 China School of Aerospace Engineering and Mechanics TongJi University Shanghai 200092 China Department of Aerospace Engineering and Mechanics Harbin Institute of Technology Harbin 150001 China

Considering the mechnoelectrical coupling, the localization of SH-waves in disordered periodic layered piezoelectric structures is studied. The waves propagating in directions normal and tangential to the layers are considered. The transfer matrices between two consecutive unit cells are obtained according to the continuity conditions. The expressions of localization factor and localization length in the disordered periodic structures are presented. For the disordered periodic piezoelectric structures, the numerical results of localization factor and localization length are presented and discussed. It can be seen from the results that the frequency passbands and stopbands appear for the ordered periodic structures and the wave localization phenomenon occurs in the disordered periodic ones, and the larger the coefficient of variation is, the greater the degree of wave localization is. The widths of stopbands in the ordered periodic structures are very narrow when the properties of the consecutive piezoelectric materials are similar and the intervals of stopbands become broader when a certain material parameter has large changes. For the wave propagating in the direction normal to the layers the localization length has less dependence on the frequency, but for the wave propagating in the direction tangential to the layers the localization length is strongly dependent on the frequency.

关键词： Disordered periodic layered piezoelectric structures Transfer matrix Lyapunov exponent Localization factor Localization length