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Statistical Modification Analysis of Helical Planetary Gears based on Response Surface Method and Monte Carlo Simulation

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Chinese Journal of Mechanical Engineering 2015年第6期28卷 1194-1203页

作者： ZHANG Jun guo fan School of Mechanical Engineering Anhui University of Technology

Tooth modification technique is widely used in gear industry to improve the meshing performance of gearings. However, few of the present studies on tooth modification considers the influence of inevitable random errors on gear modification effects. In order to investigate the uncertainties of tooth modification amount variations on system＇s dynamic behaviors of a helical planetary gears, an analytical dynamic model including tooth modification parameters is proposed to carry out a deterministic analysis on the dynamics of a helical planetary gear. The dynamic meshing forces as well as the dynamic transmission errors of the sun-planet 1 gear pair with and without tooth modifications are computed and compared to show the effectiveness of tooth modifications on gear dynamics enhancement. By using response surface method, a fitted regression model for the dynamic transmission error（DTE） fluctuations is established to quantify the relationship between modification amounts and DTE fluctuations. By shifting the inevitable random errors arousing from manufacturing and installing process to tooth modification amount variations, a statistical tooth modification model is developed and a methodology combining Monte Carlo simulation and response surface method is presented for uncertainty analysis of tooth modifications. The uncertainly analysis reveals that the system＇s dynamic behaviors do not obey the normal distribution rule even though the design variables are normally distributed. In addition, a deterministic modification amount will not definitely achieve an optimal result for both static and dynamic transmission error fluctuation reduction simultaneously.

关键词： tooth modification helical planetary gears response surface method Monte Carlo simulation

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Getting to the Bottom Morphology of Block Copolymer Thin Films

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Chinese Journal of Polymer Science 2016年第1期34卷 88-93页

作者： Wen-jin fan guo-qiang fan 张晓华杨朝晖 Center for Soft Condensed Matter Physics and Interdisciplinary Research Soochow UniversitySuzhou 215006China College of Physics Optoelectronics and EnergySoochow UniversitySuzhou 215006China SINOPEC Beijing Research Institute of Chemical Industry Beijing 100013China

We demonstrate a general approach for attaining the bottom morphology of block copolymer（BCP） thin films. In our former measurements on PS-b-PMMA films, surface morphology maps of the BCP films revealed distinct ordering regimes where the cylinders orient predominantly perpendicular or parallel to the interface and an ‘intermediate＇ regime where these morphologies coexist. However, this earlier work did not explore the bottom morphology of BCP thin films. In this study, we investigated the block copolymer morphology near the solid substrate in the cast block copolymer film having a perpendicular cylinder morphology on the surface.

关键词： Block copolymer Thin film Morphology

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Image Dehazing Based on Haziness Analysis

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International Journal of Automation and computing 2014年第1期11卷 78-86页

作者： fan guo Jin Tang Zi-Xing Cai School of Information Science and Engineering Central South University Hunan Engineering Laboratory for Advanced Control and Intelligent Automation

We present two haze removal algorithms for single image based on haziness *** algorithm regards haze as the veil layer,and the other takes haze as the *** former uses the illumination component image obtained by retinex algorithm and the depth information of the original image to remove the veil *** latter employs guided filter to obtain the refined haze transmission and separates it from the original *** main advantages of the proposed methods are that no user interaction is needed and the computing speed is relatively fast.A comparative study and quantitative evaluation with some main existing algorithms demonstrate that similar even better quality results can be obtained by the proposed *** the top of haze removal,several applications of the haze transmission including image refocusing,haze simulation,relighting and 2-dimensional(2D)to 3-dimensional(3D) stereoscopic conversion are also implemented.

关键词： Image dehazing haziness analysis retinex theory veil layer haze image model haze transmission

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Automated design of freeform imaging systems

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Light(Science & Applications) 2017年第1期6卷 431-440页

作者： Tong Yang guo-fan Jin Jun Zhu State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China

The automated design of imaging systems involving no or minimal human effort has always been the expectation of scientists,researchers and optical *** addition,it is challenging to choose an appropriate starting point for an optical system *** this paper,we present a novel design framework based on a point-by-point design process that can automatically obtain high-performance freeform *** framework only requires a combination of planes as the input based on the configuration requirements or the prior knowledge of *** point-by-point design framework is different from the decadeslong tradition of optimizing surface *** with the traditional design method,whereby the selection of the starting point and the optimization process are independent of each other and require extensive amount of human effort,there are no obvious differences between these two processes in our design framework,and the entire design process is mostly *** automated design process significantly reduces the amount of human effort required and does not rely on advanced design skills and *** demonstrate the feasibility of the proposed design framework,we successfully designed two highperformance systems as *** point-by-point design framework opens up new possibilities for automated optical design and can be used to develop automated optical design in the areas of remote sensing,telescopy,microscopy,spectroscopy,virtual reality and augmented reality.

关键词： automated design construction and iteration freeform imaging system point-by-point

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Time-dependent Density Functional-based Tight-bind Method Efficiently Implemented with OpenMP Parallel and GPU Acceleration

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Chinese Journal of Chemical Physics 2013年第6期26卷 635-645,I0003页

作者： guo-hong fan Ke-li Han guo-zhong He State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics ChineseAcademy of Sciences Dalian 116023 China

The time-dependent density functional-based tight-bind （TD-DFTB） method is implemented on the multi-core and the graphical processing unit （GPU） system for excited state calcu-lations of large system with hundreds or thousands of atoms. Sparse matrix and OpenMP multithreaded are used for building the Hamiltonian matrix. The diagonal of the eigenvalue problem in the ground state is implemented on the GPUs with double precision. The GPU- based acceleration fully preserves all the properties, and a considerable total speedup of 8.73 can be achieved. A Krylov-space-based algorithm with the OpenMP parallel and CPU acceleration is used for finding the lowest eigenvalue and eigenvector of the large TDDFT matrix, which greatly reduces the iterations taken and the time spent on the excited states eigenvalue problem. The Krylov solver with the GPU acceleration of matrix-vector product can converge quickly to obtain the final result and a notable speed-up of 206 times can be observed for system size of 812 atoms. The calculations on serials of small and large systems show that the fast TD-DFTB code can obtain reasonable result with a much cheaper computational requirement compared with the first-principle results of CIS and full TDDFT calculation.

关键词： Density-functional theory Tight-binding method Time-dependent densityfunctional theory Excited state Graphical processing unit Krylov iterative algorithm Sparse matrix OpenMP

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Nonlinear Longitudinal Attitude Control of an Unmanned Seaplane with Wave Filtering

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International Journal of Automation and computing 2016年第6期13卷 634-642页

作者： Huan Du guo-Liang fan Jian-Qiang Yi Institute of Automation Chinese Academy of Sciences

A new longitudinal attitude control system design for an unmanned seaplane in the severe sea states is presented in this paper. We develop a nonlinear passive observer, which is used to achieve wave filtering and state estimation. Moreover, the observer can be extended to achieve adaptive wave filtering in varying sea states. Using the estimated low-frequency states, a backstepping sliding mode controller is designed to keep the longitudinal attitude of the unmanned seaplane stable. The stability of the total closed loop system is analyzed by using Lyapunov theory. Simulations are performed in different wave conditions, including Seastate 3 and Seastate 5. The simulations results show that the proposed longitudinal attitude controller can improve the anti-waves capability effectively. Moreover, adaptive wave filter has a significant advantage over a filter with fixed model parameters in varying sea states.

关键词： observer backstepping unmanned sliding attitude longitudinal guaranteed disturbance filtering desired

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Penalized profile least squares-based statistical inference for varying coefficient partially linear errors-in-variables models

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Science China Mathematics 2018年第9期61卷 1677-1694页

作者： guo-liang fan Han-ying Liang Li-xing Zhu Institute of Statistics and Big Data Renmin University of China School of Mathematics and Physics Anhui Polytechnic University School of Mathematical Science Tongji University Department of Mathematics Hong Kong Baptist University School of Statistics Beijing Normal University

The purpose of this paper is two fold. First, we investigate estimation for varying coefficient partially linear models in which covariates in the nonparametric part are measured with errors. As there would be some spurious covariates in the linear part, a penalized profile least squares estimation is suggested with the assistance from smoothly clipped absolute deviation penalty. However, the estimator is often biased due to the existence of measurement errors, a bias correction is proposed such that the estimation consistency with the oracle property is proved. Second, based on the estimator, a test statistic is constructed to check a linear hypothesis of the parameters and its asymptotic properties are studied. We prove that the existence of measurement errors causes intractability of the limiting null distribution that requires a Monte Carlo approximation and the absence of the errors can lead to a chi-square limit. Furthermore, confidence regions of the parameter of interest can also be constructed. Simulation studies and a real data example are conducted to examine the performance of our estimators and test statistic.

关键词： diverging number of parameters varying coefficient partially linear model penalized likelihood SCAD variable selection

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SIMULATION OF TANK SLOSHING BASED ON OPENFOAM AND COUPLING WITH SHIP MOTIONS IN TIME DOMAIN

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Journal of Hydrodynamics 2012年第3期24卷 450-457页

作者： LI Yu-long ZHU Ren-chuan MIAO guo-ping fan Ju State Key Laboratory of Ocean Engineering School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong University Shanghai 200240 China

Tank sloshing in ship cargo is excited by ship motions, which induces impact load on tank wall and then affects the ship motion. Wave forces acting on ship hull and the retardation function are solved by using three-dimensional frequency domain theory and an impulse response function method based on the potential flow theory, and global ship motion is examined coupling with nonlinear tank sloshing which is simulated by viscous flow theory. Based on the open source Computational Fluid Dynamics （CFD） development platform Open Field Operation and Manipulation （OpenFOAM）, numerical calculation of ship motion coupled with tank sloshing is achieved and the corresponding numerical simulation and validation are carried out. With this method, the interactions of wave, ship body and tank sloshing are completely taken into consideration. This method has quite high efficiency for it takes advantage of potential flow theory for outer flow field and viscous flow theory for inside tank sloshing respectively. The numerical and experimental results of the ship motion agree well with each other.

关键词： Open Field Operation and Manipulation (OpenFOAM) time domain simulation tank sloshing and coupling effect,Impulse-Response Function (IRF)

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Assessment of subgrid-scale models in wall-modeled large-eddy simulations of turbulent channel flows

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Journal of Hydrodynamics 2023年第3期35卷 407-416页

作者： Wei-wen Zhao Fu-chang Zhou guo-qing fan De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Wuhan Second Ship Design and Research Institute Wuhan 430205China

Considering the demanding of grid requirements for high-Reynolds-number wall-bounded flow,the wall-modeled large-eddy simulation(WMLES)is an attractive method to deal with near wall ***,the effect of subgrid-scale(SGS)models for wall-bounded turbulent flow in combination with wall stress models is still *** this paper,turbulent channel flow at Reτ=1000 are numerically simulated by WMLES in conjunction with four different SGS models,i.e.,the wall-adapting local eddy-viscosity model,the dynamic Smagorinsky model,the dynamic SGS kinetic energy model and the dynamic Lagrangian *** mean velocity profiles are compared with the law of the wall,and the velocity fluctuations are compared with direct numerical simulation *** energy spectrum of velocity and wall pressure fluctuations are presented and the role of SGS models on predicting turbulent channel flow with WMLES is discussed.

关键词： Wall-modeled large-eddy simulation(WMLES) subgrid-scale(SGS)model turbulent channel flow energy spectra

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Two New Dihydroflavanoids from Patrinia villosa Juss

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Chinese Chemical Letters 2006年第2期17卷 218-220页

作者： Jin Yong PENG guo Rong fan Yu Tian WU Shanghai Key Laboratory for Pharmaceutical Metabolite Research School of Pharmacy Second Military Medical University Shanghai 200433

Two new dihydroflavonoids were obtained from the traditional Chinese medicinal herb Patrinia villosa Juss. Their structures were elucidated as （2S）-5, 7, 2＇, 6＇-tetrahydroxy-6, 8-di （γ, γ-dimethylallyl） flavanone （1） and （2S）-5, 7, 2＇, 6＇-tetrahydroxy-6-1avandulylated flavanone （2） by spectroscopic methods including UV, IR, HR-TOF-MS, 1D NMR and 2D NMR techniques.

关键词： Patrinia villosa Juss prenylated flavonoids.

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