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Numerical and experimental studies on unsupervised deep Lagrangian learning based rotor balancing method

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Science China(Technological Sciences) 2023年第4期66卷 1050-1061页

作者： ZHONG Shun hou Lei Department of Mechanics Tianjin UniversityTianjin 300000China School of Astronautics Harbin Institute of TechnologyHarbin 150001China

Rotor balancing is essential to rotor dynamic *** make the balancing process convenient and costless,a balancing method using unsupervised deep Lagrangian network without weight trail is *** the proposed network,a Lagrangian layer is applied to the network to introduce the physical prior *** to traditional balancing method,trail weight process is not ***,parameter sharing mechanics in baseline design or Lagrangian layer are applied to identify the unbalanced force without labeled *** numerical case study and corresponding experiment are conducted to validate the *** experimental and numerical results find that the proposed rotor balancing approach gives reasonable and comparative results with the considerations of both cost and *** with the baseline,to which no physical prior is applied,the balancing method with Lagrangian mechanism involved could achieve better *** proposed rotor dynamic balancing method gives out an alternative approach of rotor balancing methods.

关键词： rotor balancing unsupervised deep learning Lagrangian layer weight trial experimental rig balancing experiment

FULL DISCRETE TWO-LEVEL CORRECTION SCHEME FOR NAVIER-STOKES EQUATIONS

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Journal of Computational Mathematics 2008年第2期26卷 209-226页

作者： Yanren hou Liquan Mei College of Science Xi'an Jiaotong University Xi'an 710049 China

In this paper, a full discrete two-level scheme for the unsteady Navier-Stokes equations based on a time dependent projection approach is proposed. In the sense of the new projection and its related space splitting, non-linearity is treated only on the coarse level subspace at each time step by solving exactly the standard Galerkin equation while a linear equation has to be solved on the fine level subspace to get the final approximation at this time step. Thus, it is a two-level based correction scheme for the standard Galerkin approximation. Stability and error estimate for this scheme are investigated in the paper.

关键词： Two-level method Galerkin approximation Correction Navier-Stokes equation

MODIFIED DISCREPANCY PRINCIPLES WITH PERTURBED OPERATORS AND NOISY DATA

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Journal of Computational Mathematics 1996年第2期14卷 108-119页

作者： Chen, H hou, ZY WUHAN UNIV DEPT MATHWUHAN 430072PEOPLES R CHINA FUDAN UNIV INST MATHSHANGHAI 200433PEOPLES R CHINA

We investigate a class of a posterior parameter choice for iterated Tikhonov regularization with perturbed operators and noisy data by using modified Arcangeli's method. The rate of convergence of regularization appro... 详细信息

关键词： Ill posed problems Computational mathematics Approximation Linear transformations

Theoretical models and experimental determination methods for equations of state of silicate melts: A review

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Science China Earth Sciences 2019年第5期62卷 751-770页

作者： Juntao hou Qiong LIU MOE Key Laboratory of Orogenic Belt and Crustal Evolution School of Earth and Space Sciences Peking University

Silicate melts are very active in the interior of the Earth and other terrestrial planets, and are important carriers for the transport of material and energy. The determination of the equation of state(EOS) for silicate melts and the acquisition of a precise quantitative relationship between molar volume(or density) and temperature, pressure, and composition is essential for simulating the generation, migration, and eruption processes of magmas and the evolution of the magma ocean stage during the early formation of the Earth and other terrestrial planets, for calculating and modeling the phase equilibria involving silicate melts, and for revealing the variation of the microstructure of silicate melts with pressure. However, it is experimentally challenging to determine the volumetric properties of silicate melts and the accumulated density data at high pressure are still very limited due to a series of problems such as: the high liquidus temperature of silicate rocks; proneness for silicate melts to react with sample capsules to change the melt composition; and proneness for melts to flow and leak during the high pressure and high temperature experiments. In recent years, there is rapid progress in the high pressure and high temperature experimental techniques, in terms of not only the extension of temperature and pressure ranges but also the improvement on the accuracy of measurements, and the emergence of new methods for in-situ measurements. Here, we review the widely-used theoretical models of ambient-pressure and high-pressure EOS for silicate melts, and illustrate some problems that need to be solved urgently:(1) the room pressure EOS for iron-and titanium-bearing silicate melts needs to be improved;(2) the partial molar properties of the H2 O and CO2 components in silicate melts containing volatile components may vary markedly with the melt composition, which need to be addressed in high-pressure EOS;(3) how the formulation and applicable range of EOS corre

关键词： Silicate melts Equations of state Theoretical models Determination methods Melt structure Compression mechanisms

A FINITE DIMENSIONAL METHOD FOR SOLVINGNONLINEAR ILL-POSED PROBLEMS

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Journal of Computational Mathematics 1999年第3期17卷 315-326页

作者： Jin, QN hou, ZY Nanjing Univ Inst Math Nanjing 210008 Peoples R China Fudan Univ Inst Math Shanghai 200433 Peoples R China

We propose a finite dimensional method to compute the solution of nonlinear ill-posed problems approximately and show that under certain conditions, the convergence can be guaranteed. Moreover, we obtain the rate of convergence of our method provided that the true solution satisfies suitable smoothness condition. Finally, we present two examples from the parameter estimation problems of differential equations and illustrate the applicability of our method.

关键词： nonlinear ill-posed problems finite dimensional method convergence and convergence rates

A NEW NEURAL NETWORK-BASED ADAPTIVE ILC FOR NONLINEAR DISCRETE-TIME SYSTEMS WITH DEAD ZONE SCHEME

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Journal of Systems Science & Complexity 2009年第3期22卷 435-445页

作者： Ronghu CHI Zhongsheng hou Institute of Autonomous Navigation and Intelligent Control School of Automation and Electrical EngineeringQingdao University of Science and Technology Qingdao 266042 China. Advanced Control Systems Laboratory School of Electronics and Information Engineering Beijing JiaotongUniversity Beijing 100044 China.

By introducing a deadwzone scheme, a new neural network based adaptive iterative learning control （ILC）（NN-AILC） scheme is presented for nonlinear discrete-time systems, where the NN weights are time-varying. The most distinct contribution of the proposed NN-AILC is the relaxation of the identical conditions of initial state and reference trajectory, which are common requirements in traditional ILC problems. Convergence analysis indicates that the tracking error converges to a bounded ball, whose size is determined by the dead-zone nonlinearity. Computer simulations verify the theoretical results.

关键词： Adaptive control iterative learning control neural network non-identical initial condition,non-identical trajectory.

Multiscale mechanical modeling of hydrated cement paste under tensile load using the combined DEM-MD method

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Frontiers of Structural and Civil Engineering 2017年第3期11卷 270-278页

作者： Yue hou Linbing WANG National Center for Materials Service Safety University of Science and Technology Beijing Beijing 100083 China Joint USTB-Virginia Tech Lab on Multifunctional Materials USTB Beijing Virginia Tech Blacksburg VA 24061 USA

In this paper, a combined DEM-MD method is proposed to simulate the crack failure process of Hydrated Cement Paste （HCP） under a tensile force. A three-dimensional （3D） multiscale mechanical model is established using the combined Discrete Element Method （DEM）-Molecular Dynamics （MD） method in LAMMPS （Large-scale Atomic/ Molecular Massively Parallel Simulator）. In the 3D model, HCP consists of discrete particles and atoms. Simulation results show that the combined DEM-MD model is computationally efficient with good accuracy in predicting tensile failures of HCP.

关键词： hydrated cement paste multiscale MD simulation DEM

Effects of large-amplitude internal solitary waves on ROV operation--A numerical study

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Science China Earth Sciences 2016年第5期59卷 1074-1080页

作者： SHEN Hui hou YiJun Nanjing University of Information Science and Technology Naniine 210044 China Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China

Remotely operated vehicles(ROVs) are unique tools for underwater industrial exploration and scientific research of offshore areas and the deep ocean. With broadening application of ROVs, the study of factors that affect their safe operation is important. Besides the technical skills to control ROV movement, the dynamical ocean environment may also play a vital role in the safe operation of ROVs. In this paper, we investigate the influence of large-amplitude internal solitary waves(ISWs), focusing on the forces exerted on ROVs by ISWs. We present a methodology for modeling ISW-induced currents based on Kd V model and calculate the ISW forces using the Morrison equation. Our results show that an extremely considerable load is exerted by the ISW on the ROV, resulting in a strong disturbance of the vehicle's stability, affecting the ROV control. The numerical results of this work emphasize the importance of considering dynamical conditions when operating underwater vessels, such as ROV. Further laboratory and field investigation are suggested to gain more understanding of this subject.

关键词： Remotely operated vehicle Internal solitary waves Morrison equation

Synthesis of a Magnetic Core-shell Fe_(3)O_(4)@Cu_(3)(BTC)_(2) Catalyst and Its Application in Aerobic Olefin Epoxidation

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Chemical Research in Chinese Universities 2023年第6期39卷 1044-1050页

作者： hou Junying hou Chuanyuan LI Jianchang HAO Jianjun College of Mechanical and Electrical Engineering Hebei Agriculture UniversityBaoding 071001P.R.China

Olefin epoxidation is a fundamental reaction in organic ***,a novel magnetic core-shell Fe_(3)O_(4)@Cu_(3)(BTC)_(2) metal-organic framework(MOF)heterogeneous catalyst was synthesized for the use in olefin ***,the size selectivity of the Fe_(3)O_(4)@Cu_(3)(BTC)_(2) catalyst in olefin epoxidation was *** electron microscopy(SEM)and transmission electron microscopy(TEM)results indicated that Fe_(3)O_(4)@Cu_(3)(BTC)_(2) presented a microsphere morphology,and Cu_(3)(BTC)_(2) MOFs were well dispersed on the Fe_(3)O_(4)(PAA)surface after 10 cycles of the synthesis *** synthesized magnetic core-shell Fe_(3)O_(4)@Cu_(3)(BTC)_(2) heterogeneous catalyst could facilitate efficient aerobic olefin ***,the catalyst was used in the aerobic oxidation of alcohols and was found to exhibit excellent activity for primary alcohols.

关键词： Core-shell Metal-organic framework(MOF) Heterogeneous catalyst Molecular oxygen Olefin epoxidation Alcohol oxidation