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Acta Mechanica Sinica 2021年第9期37卷 1446-1456,I0003页

作者： biao hu Juan Liu Yuxing Wang Bo Zhang huoming Shen Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiao Tong UniversityChengdu610031China

Αn analytical method is developed to explore the wave propagation characteristics of piezoelectric sandwich nanoplates in the present *** sandwich nanoplates are composed of a graphene reinforced composite core layer with two piezoelectric surface layers exposed to electric *** material properties of the nanocomposite layer are given by the Halpin–Tsai model and mixture’s *** Euler–Lagrange equation of the nanoplates is obtained by Hamilton's principle and first-order shear deformation ***,combining the high-order nonlocal strain gradient theory with the hygrothermal constitutive relationship of composite nanoplates,the nonlocal governing equations are ***,numerical studies are conducted to demonstrate the influences of scale parameters,applied external voltage,temperature variation,moisture variation,graphene size,and weight fraction on wave *** results reveal that low-order and high-order nonlocal parameters and length scale parameters have different effects on wave *** wave frequency can be reduced by increasing temperature and the thickness of *** could facilitate the investigation of the dynamic properties of graphene nanocomposite structures.

关键词： Wave propagation High-order nonlocal strain gradient theory Piezoelectric sandwich nanoplates Graphene platelets Hygrothermal environment

Composite quantile regression estimation for P-GARCH processes

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Science China Mathematics 2016年第5期59卷 977-998页

作者： ZHAO biao chen Zhao TAO GuiPing chen Min Department of Statistics and Finance University of Science and Technology of China Department of Statistics Pennsylvnia State University School of Statistics Capital University of Economics and Business Academy of Mathematics and Systems Science Chinese Academy of Sciences

We consider the periodic generalized autoregressive conditional heteroskedasticity(P-GARCH) process and propose a robust estimator by composite quantile regression. We study some useful properties about the P-GARCH model. Under some mild conditions, we establish the asymptotic results of proposed *** Monte Carlo simulation is presented to assess the performance of proposed estimator. Numerical study results show that our proposed estimation outperforms other existing methods for heavy tailed *** proposed methodology is also illustrated by Va R on stock price data.

关键词： composite quantile regression periodic GARCH process strictly periodic stationarity strong consistency asymptotic normality

Exact Analytical Solutions in Bose-Einstein Condensates with Time-Dependent Atomic Scattering Length

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Communications in Theoretical Physics 2007年第1期47卷 143-148页

作者： chen Yong LI biao ZHENG Yu Nonlinear Science Center and Department of Mathematics Ningbo University Ningbo 315211 China Department of Mathematics East China Normal University Shanghai 200062 China MM Key Lab the Chinese Academy of Sciences Beijing 100080 China

In the paper, the generalized Riccati equation rational expansion method is presented. Making use of the method and symbolic computation, we present three families of exact analytical solutions of Bose-Einstein condensates with the time-dependent interatomic interaction in an expulsive parabolic potential. Then the dynamics of two anlytical solutions are demonstrated by computer simulations under some selectable parameters including the Feshbach-managed nonlinear coefficient and the hyperbolic secant function coefficient.

关键词： NLS equation soliton symbolic computation

Techniques for Radar Imaging Based onMUSIC Algorithm

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Journal of Systems Engineering and Electronics 1999年第1期10卷 31-38页

作者： Guo, biao Lu, Xiaoying chen, Zengping Air Force Inst of Radar Beijing China

At first, the radar target scattering centers model and MUSIC algorithm are analyzed in this paper. How to efficiently set the parameters of the MUSIC algorithms is given by a great deal of simulated radar data in experiments. After that, according to measured data from two kinds of plane targets on fully polarized and high range resolution radar system, the author mainly investigated particular utilization of MUSIC algorithm in radar imaging. And two-dimensional radar images are generated for two targets measured in compact range. In the end, a conclusion is drew about the relation of radar target scattering properties and imaging results.

关键词： Algorithms Electromagnetic wave scattering Mathematical models Radar systems Radar target recognition

Differences in both the structure and interaction of the crust and mantle on the eastern and western sides of the Ordos Block

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Science China Earth Sciences 2024年第12期67卷 3900-3913页

作者： Yong chen Yifang chen Jiuhui chen biao GUO Yu LI Panpan ZHAO State Key Laboratory of Seismic Dynamics Institute of GeologyChina Earthquake AdministrationBeijing 100029China National Field Scientific Observatory for Continental Rift Valley Dynamics in Taiyuan Beijing 100029China Institute of Earthquake Forecasting China Earthquake AdministrationKey Laboratory for Earthquake PredictionBeijing 100036China

The Ordos Block,the western part of the North China Craton(NCC),has preserved most of its cratonic lithospheric roots during the destruction and modification of the NCC,and nowconnects two distinctly different tectonic units,i.e.,the Tibetan Plateau(TP)to the west and the North China Plain to the *** is important to studythe detailed crust-mantle structure of the Ordos Block and surroundings to understand the interactions between the Ordos and adjacent regions and the dynamics of the NCC *** this study,the S-wave velocity structure at depths of 0–100 km along an E-W profile at around 36.5°N from the Qilian orogen(QLO)to the Trans-North China Orogen(TNCO)within the NCC was investigated by joint inversion of the receiver functions(RFs)and surface wave dispersion data from 104 broadband seismic stations deployed in the region under the ChinArray project(PhaseⅡand PhaseⅢ).The image of discontinuity structures along the profile was further constructed by common conversion point stacking of *** main results are as follows:(1)The depth of the Moho in the study region gradually decreases from west to east,being the deepest in the QLO,the second in the Ordos Block,and the shallowest in the *** depression and uplift of the Moho are also identified beneath the Haiyuan fault zone and the Shanxi-Shaanxi rift system(SSR),respectively.(2)The crust-mantle structure displays obvious lateral heterogeneities among tectonic regions.A pronounced low-velocity anomaly is observed at depths of 20–40 km beneath the QLO and becomes weakened and thinned to the east,indicating that thickening of the mid-to-lower crust probably occurred in the QLO during the growth and lateral extrusion of the northeastern TP under the resistance of the *** lithosphere-asthenosphere boundary beneath the TNCO is imaged at~90 km depth,which is significantly shallower than that beneath the Ordos *** observation suggests that the lithosphere of the TNCO may have experienced a nota

关键词： Ordos Block Qilian orogen Shanxi-Shaanxi rift system Mid-to-lower crustal thickening Mantle upwelling

Resonant Quantum Search with Monitor Qubits

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Chinese Physics Letters 2020年第5期37卷 15-19页

作者： Frank Wilczek Hong-Ye hu biao Wu Center for Theoretical Physics MITCambridgeMA 02139USA D.Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China Wilczek Quantum Center School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Department of Physics Stockholm UniversityStockholmSE-10691Sweden Department of Physics Arizona State UniversityTempeAZ 25287USA Department of Physics University of CalifornianSan DiegoCA 92093USA International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China

We present an algorithm for the generalized search problem(searching k marked items among N items)based on a continuous Hamiltonian and exploiting *** resonant algorithm has the same time complexity O(√N/k)as the Grover algorithm.A natural extension of the algorithm,incorporating auxiliary"monitor"qubits,can determine k precisely,if it is *** time complexity of our counting algorithm is O(√N),similar to the best quantum approximate counting algorithm,or better,given appropriate physical resources.

关键词： resonant Hamiltonian auxiliary

A Diffusive Predator-Prey Model with Spatially Heterogeneous Carrying Capacity

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Journal of Partial Differential Equations 2023年第4期36卷 435-453页

作者： chen Jiawei WANG biao College of Science Xi'an University of Science and TechnologyXi'an 710054China

We study local dynamics of a diffusive predator-prey model in a spatially heterogeneous environment,where intrinsic growth rate of the prey is spatially ho-mogeneous,whereas carrying capacity of the habitat is spatially *** comparison with the existing predator-prey models,the stability of semi-trivial steady state of this model displays distinct *** example,for certain intermediate ranges of the death rate of the predator,the semi-trivial steady state can change its stability at least once as the dispersal rate of the prey varies from small to large,while the stability of the semi-trivial steady state is immune from the dispersal rate of the predator.

关键词： Predator-prey model carrying capacity spatial heterogeneity stability

Infrared radiation characteristics of a hypersonic vehicle under time-varying angles of attack

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Chinese Journal of Aeronautics 2019年第4期32卷 861-874页

作者： Qinglin NIU Zhichao YUAN biao chen Shikui DONG School of Energy Science and Engineering Harbin Institute of Technology Key Laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology Harbin Institute of Technology Key Laboratory of Chemical Laser Dalian Institute of Chemical Physics Chinese Academy of Sciences

Hypersonic vehicles emit strong infrared(IR) radiation signatures that can be treated as a detecting source for object identification and routine diagnosis. This paper is aimed at examining the intrinsic radiation characteristics of a Boost-Glide Vehicle(BGV) under the condition of various Angles of Attack(AOAs). A two-temperature model considering the thermal and chemical nonequilibrium effects is coupled with Navier-Stokes equations solved by the finite volume technique.A gas–solid conjunction heat transfer model is also added into the fluid solver to simulate the surface temperature of the vehicle. The radiative transfer equation is solved with Line of Sight(LOS)algorithm. The computational results for a Hypersonic Technology Vehicle-2(HTV-2) type vehicle show that radiances of the vehicle are strongly dependent on the surface temperature. The presence of AOA results in the significant difference of the surface temperature. Infrared radiation characteristics are also changed in intensity and spectral band due to the AOA. Simulations are performed with two time-varying AOAs. Transient results indicate that the variation of AOA does have a great effect on the infrared radiance and is closely related to observation angle, spectral band, angle size,angular velocity and time history.

关键词： Angle of attack Fluid-thermal interaction HTV-2 Hypersonic vehicle IR radiation Surface temperature

Novel approach for determining the optimal axial preload of a simulating rotary table spindle system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 812-817页

作者： SHAN Xiao-biao XIE Tao chen Wei-shan School of Mechatronics Engineering Harbin Institute of Technology Harbin 15001 China

This paper presents a new theoretical model to determine the optimal axial preload of a spindle system, for challenging the traditional method which relies heavily on experience of engineers. The axial preloading stiffness was treated as the sum of the spindle modal stiffness and the framework elastic stiffness, based on a novel concept that magnitude of preloads can be controlled by measuring the resonant frequency of a spindle system. By employing an example of a certain type of aircraft simulating rotary table, the modal stiffness was measured on the Agilent 35670A Dynamic Signal Analyzer by experimental modal analysis. The equivalent elastic stiffness was simulated by both finite element analysis in ANSYS? and a curve fitting in MATLAB?. Results showed that the static preloading stiffness of the spindle was 7.2125×107 N/m, and that the optimal preloading force was 120.0848 N. Practical application proved the feasibility of our method.

关键词： Three-axis simulating rotary table Axial position preload Stiffness Experimental modal analysis Finite elementanalysis

Orthogonal procrustes based semi-blind MIMO channel estimation under space-time block code transmissions

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 20-24页

作者： hu Feng JIN Li-biao LI Jian-zeng School of Information Engineering Communication University of China Beijing 100024 China

This work investigates a novel semi-blind channel estimation for multiple-input multiple-output （MIMO） space-time block coding （STBC） systems. Algorithms for channel estimation based on whitening-rotation （WR） decomposition that provides a combined quality and spatial scalability is utilized. Using a space-time code-constrained input design, our approach exploits the orthogonality of the signal and noise subspaces in conjunction with orthogonal procrustes （OP） technique to obtain an accurate estimate of the unitary rotation matrix and, consequently, of the channel parameters. Unitary rotation matrices are parameterized a much fewer number of parameters, and significant estimation gains can then be achieved by estimation of such orthogonal matrices. Furthermore, the proposed semi-blind MIMO channel estimation approach is conducted to reduce the complexity of system design when the number of the receive antennas is no less than the number of transmit antennas. Computer simulations are conducted to corroborate the effectiveness of the proposed channel estimation, and they demonstrate the improved performance compared to the existing training-based estimation.

关键词： MIMO semi-blind channel estimation STBC orthogonal procrustes singular value decomposition