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Numerical simulation on the adaptation of forms in trabecular bone to mechanical disuse and basic multi-cellular unit activation threshold at menopause

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Acta Mechanica Sinica 2008年第2期24卷 207-214页

作者： He Gong Yubo fan ming zhang Department of Health Technology and Informatics The Hong Kong Polytechnic University Hong Kong China Department of Bioengineering Beihang UniversityBeijing 100083 China Department of Mechanics Jilin University Changchun 130012 China

The objective of this paper is to identify the effects of mechanical disuse and basic multi-cellular unit （BMU） activation threshold on the form of trabecular bone during menopause. A bone adaptation model with mechanical- biological factors at BMU level was integrated with finite element analysis to simulate the changes of trabecular bone structure during menopause. Mechanical disuse and changes in the BMU activation threshold were applied to the model for the period from 4 years before to 4 years after menopause. The changes in bone volume fraction, trabecular thickness and fractal dimension of the trabecular structures were used to quantify the changes of trabecular bone in three different cases associated with mechanical disuse and BMU activation threshold. It was found that the changes in the simulated bone volume fraction were highly correlated and consistent with clinical data, and that the trabecular thickness reduced signi-ficantly during menopause and was highly linearly correlated with the bone volume fraction, and that the change trend of fractal dimension of the simulated trabecular structure was in correspondence with clinical observations. The numerical simulation in this paper may help to better understand the relationship between the bone morphology and the mecha-nical, as well as biological environment; and can provide a quantitative computational model and methodology for the numerical simulation of the bone structural morphological changes caused by the mechanical environment, and/or the biological environment.

关键词： Disuse Activation Trabecular bone Menopause Functional adaptation

Emergent vegetation flow with varying vertical porosity

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Journal of Hydrodynamics 2019年第5期31卷 1043-1051页

作者： ming-deng Zhao Zi-long fan State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Department of Engineering and Information Technology China International Water and Electric Corporation(CWE)Beijing 100120China China Three Gorges Corporation(CTG) Beijing J 00038China

The vertical distribution of an emergent vegetation in wetlands and marshes is generally non-uniform due to the variations of the stem thickness and the leaf *** study focuses on the effect of the varying vertical porosity on the hydrodynamic characteristics of the emergent vegetation *** new governing equation for the emergent vegetation flow with varying vertical porosity is established by applying the poroelastic media flow *** to the movement mechanism of the water flow in the porous media and the experimental data,the best fitted expression of the permeability is established for the emergent vegetation *** velocity distribution is obtained with the finite analytic ***,a flume experiment is performed using truncated cones to simulate the actual vegetation with varying vertical *** calculated velocity distribution is compared with the measured data,which shows that the theoretical results are in good agreement with the experimental ***,the influence of the vertical porosity distribution on the vegetation flow characteristics is analyzed *** study can provide a useful reference and technical support for further study of the flow with a complex shape vegetation.

关键词： Emergent vegetation flow velocity distribution varying vertical porosity finite analytic method Biot^poroelastic theory

Robust optimization of the billet for isothermal local loading transitional region of a Ti-alloy rib-web component based on dual-response surface method

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Frontiers of Mechanical Engineering 2018年第3期13卷 376-384页

作者： Ke WEI Xiaoguang fan Mei zhan Miao MENG State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710071 China

Billet optimization can greatly improve the forming quality of the transitional region in the isothermal local loading forming （ILLF） of large-scale Ti-alloy ribweb components. However, the final quality of the transitional region may be deteriorated by uncontrollable factors, such as the manufacturing tolerance of the preforming billet, fluctuation of the stroke length, and friction factor. Thus, a dual-response surface method （RSM）-based robust optimization of the billet was proposed to address the uncontrollable factors in transi- tional region of the ILLF. Given that the die underfilling and folding defect are two key factors that influence the forming quality of the transitional region, minimizing the mean and standard deviation of the die underfilling rate and avoiding folding defect were defined as the objective function and constraint condition in robust optimization. Then, the cross array design was constructed, a dual-RSM model was established for the mean and standard deviation of the die underfilling rate by considering the size parameters of the billet and uncontrollable factors. Subsequently, an optimum solution was derived to achieve the robust optimization of the billet. A case study on robust optimization was conducted. Good results were attained for improving the die filling and avoiding folding defect, suggesting that the robust optimization of the billet in the transitional region of the ILLF was efficient and reliable.

关键词： isothermal local loading forming rib-web component transitional region robust optimization dual response surface method

Deformation warning index for reinforced concrete dam based on structural health monitoring data and numerical simulation

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Water Science and Engineering 2023年第4期16卷 408-418页

作者： ming-qiang zhan Bo Chen Zhong-ru Wu State Key Laboratory of Hydrology–Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing 210098China Fujian Shuikou Power Generation Group Co. Ltd.Fuzhou 350004China

The material mechanical parameters of the dam body and foundation will change when a dam is reinforced during the aging *** causes significant changes in the structural state of the project and makes it difficult to ensure its structural *** this study,a new deformation warning index for reinforced concrete dams was developed according to the prototype monitoring data,statistical models,three-dimensional finite element model(FEM)numerical simulation,and the critical conditions of the dam structure.A statistical model was established to separate the water pressure ***,a three-dimensional FEM of the reinforced concrete dam was constructed to simulate the water pressure ***,the deformation components that affected the mechanical parameters of the dam under the same amount of reservoir water level change were separated and quantified *** addition,the method for inversion of comprehensive mechanical parameters after dam reinforcement was *** influence mechanisms of the deformation behavior of concrete dams under the reservoir water level and temperature changes were investigated.A new deformation warning index was developed by combining the forward-simulated critical water pressure component and temperature component in the period of extreme temperature decrease with the aging component separated by the statistical *** new deformation warning index considers the structural state of the dam before and after reinforcement and links the structural strength criterion and the deformation evolution *** provides a theoretical foundation and decision support for long-term service and operation management of reinforced dams.

关键词： Deformation warning index Structural health monitoring Finite element simulation Reinforcement Multiple-arch dam Parameter inverse analysis

An optimized texture-by-numbers synthesis method and its visual applications

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Science China(Information Sciences) 2013年第5期56卷 50-63页

作者： fan Jing SHI XiaoYing ZHOU zhan TANG Ying School of Computer Science and Technology Zhejiang University of Technology Key Laboratory of Visual Media Intelligent Processing Technology of Zhejiang Province School of Information Engineering Zhejiang University of Technology

The framework of texture-by-numbers(TBN) synthesizes images of global-varying patterns with intuitive user *** TBN synthesis methods have difficulties in achieving high-quality synthesis results and efficiency *** paper proposes a fast TBN synthesis method based on texture optimization,which uses global optimization to solve the controllable non-homogeneous texture synthesis *** algorithm produces high quality synthesis results by combining texture optimization into TBN framework with two *** initialization process is adopted to generate the initial output of the global optimization algorithm,which speeds up the algorithm’s convergence rate and enhances synthesis *** distance metrics to measure image similarities are specifically designed for different images to better match human visual perception for structural patterns and a user study is conducted to verify the effectiveness of the *** further improve the synthesis speed,the algorithm is entirely implemented on GPU based on CUDA *** optimized TBN method is applied to various visual applications including not only traditional TBN applications,but also image in-painting and texture-based flow *** experimental results show that our method synthesizes images of higher or comparable qualities with higher efficiency than other state-of-art synthesis methods.

关键词： texture-by-number texture optimization feature synthesis CUDA

Electrostatic Encapsulation of Cobalt Ions into Crystalline Framework Derived Polymer Aerogel:Ultra-light,Pressure Resistant,Hydrophobic,Photothermal Conversion,Heat Insulation and Infrared Stealth

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Chinese Journal of Polymer Science 2024年第7期42卷 946-957,I0007页

作者： Yi-fan Kang Jin-Lu Tang ming Song Wei Wang Jia-Cheng Ma zhan-You Ji Tong Liu Wen-Huan Huang China Key Laboratory of Chemical Additives for China National Light Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and TechnologyXi’an710021China College of New Energy Xi’an Shiyou UniversityXi’an710065China Xi’an Key Laboratory of Functional Supramolecular Structure and Materials College of Chemistry and Materials ScienceNorthwest UniversityXi’an710127China

A variety of electromagnetic wave absorption materials(EMWAs)have been reported,but the integration of powder materials and multifunctional devices should be investigated in-depth to adapt to practical ***,carbon-coated cobalt composites were prepared by adsorbing magnetic metal cations into an anionic crystalline framework through an electrostatic encapsulate *** reflection loss(RL_(min))of-40.49 d B and effective absorption bandwidth(EAB)of 5.36 GHz(RL<-10 d B,10.4-15.76 GHz)was achieved with an optimal radar cross section(RCS)reduction of 34.9 dB·m^(2) for the sample *** commercial applications,Co@CN-4 was integrated into sodium carboxymethyl cellulose(CMC)aerogel to create an ultra-lightweight composite aerogel that is compressive resistant and heat-holding while also having photothermal conversion *** hydrophobic modification makes it more widely *** study provides a new strategy for EWAMs to integrate versatility and improve their application prospects.

关键词： Electrostatic incorporation Magnetic nanoparticle Co@CN composites Electromagnetic wave absorbing Metal-organic framework

Modeling the blast load induced by a close-in explosion considering cylindrical charge parameters

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Defence Technology（防务技术） 2023年第6期24卷 83-108页

作者： Yi fan Li Chen zhan Li Heng-bo Xiang Qin fang State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of the PLANanjingJiangsu210007China Engineering Research Center of Safety and Protection of Explosion&Impact of the Ministry of Education Southeast UniversityNanjingJiangsu211189China

Structural damage is significantly influenced by the various parameters of a close-in *** establish a close-in blast loading model for cylindrical charges according to these parameters,a series of field experiments and a systematic numerical analysis were conducted.A high-fidelity finite element model developed using AUTODYN was first validated using blast data collected from field tests conducted in this and previous studies.A quantitative analysis was then performed to determine the influence of the charge shape,aspect ratio(length to diameter),orientation,and detonation configuration on the characteristics and distributions of the blast loading(incident peak overpressure and impulse)according to scaled *** results revealed that the secondary peak overpressure generated by a cylindrical charge was mainly distributed along the axial direction and was smaller than the overpressure generated by an equivalent spherical *** effects of charge shape on the blast loading at 45°and 67.5°in the axial plane could be neglected at scaled distances greater than 2 m/kg^(1/3);the effect of aspect ratios greater than 2 on the peak overpressure in the 90°(radial)direction could be neglected at all scaled distances;and double-end detonation increased the radial blast loading by up to 60%compared to singleend ***,an empirical cylindrical charge blast loading model was developed considering the influences of charge aspect ratio,orientation,and detonation *** results obtained in this study can serve as a reference for the design of blast tests using cylindrical charges and aid engineers in the design of blast-resistant structures.

关键词： Cylindrical charge Secondary peak overpressure Aspect ratio Orientation Detonation initiation point Blast loading model

Drag reduction and hairpin packets of the turbulent boundary layer over the superhydrophobic-riblets surface

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Journal of Hydrodynamics 2021年第3期33卷 621-635页

作者： Xin-wei Wang Zi-ye fan zhan-qi Tang Nan Jiang School of Mechanical Engineering Tianjin UniversityTianjin300354China Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin300354China

This paper presents experimental measurements by the time-resolved particle image velocimetry(TR-PIV)for the turbulent boundary layer(TBL)over the smooth surface,the superhydrophobic(SH)surface,and the superhydrophobic-riblets(SR)surface in an open-surface recirculating water *** Reynolds number based on the wall friction velocity and the thickness of the TBL over the smooth surface is *** SH surface and the SR surface are manufactured by the laser texturing method on the smooth surface and the riblets surface,*** employing the(modified)Clauser method,a superior efficacy of the drag reduction of about 22.1%is obtained on the SR surface,while the drag reduction rate for the SH surface is about 18.7%.Comparing with the SH surface,the declining 2-order statistics in the near-wall region also indicates a significant drag reduction over the SR *** large-scale structure components extracted by the proper orthogonal decomposition are found to generate a majority of the Reynolds shear stress in the region y^(+)>*** strength of the large-scale features over the rough surfaces(SH and SR surfaces)at disparate wall-normal positions is visualized by the Quadrant splitting method and the conditional *** appearance of the large-scale structures such as the hairpin packets characterized by the two-point correlation shows an excellent consistency with the statistics *** hairpin packets over the SH surface seem always smaller and weaker than those over the smooth *** the SR surface,the hairpin packets in the region 0.1≤y/δ<0.3 are the smallest and weakest among those over the three surfaces,while the scale and the strength of the hairpin packets exceed those over the smooth surface in the region 0.3

关键词： Turbulent boundary layer superhydrophobic riblets drag reduction hairpin packets

Quantum coherence of multiqubit states in correlated noisy channels

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Science China(Physics,Mechanics & Astronomy) 2020年第3期63卷 116-119页

作者： ming-Liang Hu Heng fan School of Science Xi’an University of Posts and TelecommunicationsXi’an 710121China Institute of Physics Chinese Academy of SciencesBeijing 100190China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

Quantum coherence captures the essential nature of a quantum system[1]and can serve as a resource for quantum information processing[2].Recent studies also provide evidence that long-lived quantum coherence is crucial for overcoming the classical limits of measurement accuracy in quantum metrology[3-5].However,in practice,the unavoidable interaction of a principal system with its surroundings results in decoherence in most ***,the advantage of quantum coherence in empowering the performance of quantum tasks will disappear in a very short time interval,which remains one of the major obstacles in its potential application.

关键词： quantum system disappear