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Quasisymmetric property for conjugacies between Anosov diffeomorphisms of the two-torus

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Science China Mathematics 2010年第3期53卷 663-670页

作者： hu huyi 1 & JIANG YunPing 2, 1 Department of Mathematics, Michigan State University, East Lansing, MI 48824, USA 2 Department of Mathematics, the Graduate Center and Queens College of CUNY, Flushing, NY 11367, USA Department of Mathematics Michigan State University East Lansing USA Department of Mathematics the Graduate Center and Queens College of CUNY Flushing USA

We prove that the restrictions of the conjugacy between two Anosov diffeomorphisms of the twotorus to the stable and unstable manifolds are quasisymmetric homeomorphisms.

关键词： quasisymmetry Anosov diffeomorphisms conjugacy Hlder condition Markov partition

Numerical simulation of quasi-static compression on a complex rubber foam

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Acta Mechanica Solida Sinica 2017年第3期30卷 285-290页

作者： huyi Wang Wenjun hu Fengpeng Zhao Institute of Systems Engineering CAEP Mianyang 621900 China

A complex rubber foam under quasi-static compression is simulated using the finite element method （FEM）, The present work sets up the phenomenological constitutive model for the silicon rubber, The computerized tomography （CT） technique is utilized to reconstruct the real complex foam geometries, The quasi-static uniaxial compression on the foam is simulated in ABAQUS. The present work obtains the stress response as the nominal strain nearly reaches 80% and the foam exhibits hyper-elastic behavior, The FEM results achieve good agreements with the data obtained from the multi-scale simulation and the tests as the nominal strain is less than 60%.

关键词： Complex Rubber Foam Quasi-static Compression

稳定型咬合板治疗伴偏侧咀嚼单侧不可复性盘前移位患者MRI研究

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中华老年口腔医学杂志 2024年第2期22卷 95-100页

作者：徐鑫宇黄东宗王岩刘刚胡一帆胡敏刘洪臣姜华解放军总医院第一医学中心口腔修复科北京100853 解放军总医院第一医学中心放射诊断科北京100853 解放军总医院第一医学中心口腔颌面外科北京100853 解放军总医院口腔医学研究所口腔颌面战创伤军队重点实验室口腔颌面修复军队医学重点实验室

目的通过MRI评估稳定型咬合板治疗伴偏侧咀嚼单侧不可复性盘前移位患者的疗效。方法选取在解放军总医院第一医学中心口腔科就诊,经过临床检查及影像学检查诊断为单侧不可复性颞下颌关节盘前移位患者34例,根据其是否存在偏侧咀嚼习惯,将... 详细信息

目的通过MRI评估稳定型咬合板治疗伴偏侧咀嚼单侧不可复性盘前移位患者的疗效。方法选取在解放军总医院第一医学中心口腔科就诊,经过临床检查及影像学检查诊断为单侧不可复性颞下颌关节盘前移位患者34例,根据其是否存在偏侧咀嚼习惯,将其分为伴偏侧咀嚼组(17例)和无偏侧咀嚼组(17例),分析患者最大开口度、疼痛指数、关节盘长度、盘分界角、关节盘位置以及翼外肌特点。采用SPSS25.0软件对结果进行统计分析。结果稳定型咬合板治疗前,伴偏侧咀嚼(chewing side preference,CSP)组患者同侧关节盘-髁突角度(61.13±10.54°)大于无CSP组(51.12±17.27°);伴CSP组同侧、对侧关节盘-髁突角度差值(52.52±10.91°)大于无CSP组差值(41.26±17.78°);伴CSP组同侧、对侧翼外肌下头面积差值(-0.43±3.66mm2)小于无CSP组同侧、对侧翼外肌下头面积差值(0.288±4.57mm2),差异均有统计学意义(P0.05);稳定型咬合板治疗后两组患者关节盘-髁突角度、关节盘长度减小,差异均有统计学意义(P0.05)。两组稳定型咬合板治疗后翼外肌上、下头长度、厚度和面积的平均值接近,差异无统计学意义(P>0.05)。Logistic回归分析显示,MMO(OR=0.743)与偏侧咀嚼存在相关性(P<0.05)。结论MRI能无创诊断ADDWoR,伴CSP的单侧ADDWoR患者患侧关节移位更加显著,且单侧ADDWoR患者MMO与CSP存在相关性,通过稳定型咬合板治疗能显著改善ADDWoR患者开口度及疼痛症状,缓解关节盘受压及关节盘移位程度。

关键词：稳定型咬合板不可复性颞下颌关节盘前移位偏侧咀嚼 MRI

决定性动力系统中的随机现象:动力系统统计理论简介

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中国科学：数学 2017年第12期47卷 1665-1680页

作者：胡虎翼南方科技大学数学系深圳518055 Department of Mathematics Michigan State University

本文简要介绍动力系统的统计理论研究中所得到的一些概率定律.考虑动力系统(M,f)相空间M上的函数φ,随着系统演化,函数族{φ?fn}可以看作一个过程.虽然这个过程是确定性的,但是当系统的运动具有一定的紊动性,且函数φ具有一定的正则性时... 详细信息

本文简要介绍动力系统的统计理论研究中所得到的一些概率定律.考虑动力系统(M,f)相空间M上的函数φ,随着系统演化,函数族{φ?fn}可以看作一个过程.虽然这个过程是确定性的,但是当系统的运动具有一定的紊动性,且函数φ具有一定的正则性时,这个过程具有随机过程的很多性质,例如,服从大数定律、中心极限定理、重对数律、大偏差原理、局部极限定理和几乎确定不变性原理等.

关键词：动力系统统计性质双曲性物理测度大数定律中心极限定理几乎确定不变原理

Isometric Embeddings of Subsets of Boundaries of Teichmüller Spaces of Compact Hyperbolic Riemann Surfaces

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Acta Mathematica Sinica,English Series 2020年第5期36卷 605-619页

作者： Guang Ming hu Yi QI College of Science Jinling Institute of TechnologyNanjing 211169P.R.China LMIB and School of Mathematics and Systems Science Beihang UniversityBeijing 100191P.R.China

It is known that every finitely unbranched holomorphic covering π:S→S of a compact Riemann surface S with genus g≥2 induces an isometric embedding Φπ:Teich(S)→Teich(S).By the mutual relations between Strebel rays in Teich(S)and their embeddings in Teich(S),we show that the 1 st-strata space of the augmented Teichmüller space Teich(S)can be embedded in the augmented Teichmüller space Teich(S)***,we show that Φπ induces an isometric embedding from the set Teich(S)B(∞)consisting of Busemann points in the horofunction boundary of Teich(S)into Teich(S)B(∞)with the detour metric.

关键词： Teichmüller space augmented Teichmüller space Strebel ray Busemann points

NUMERICAL SIMULATION OF QUASI-STATIC COMPRESSION ON A COMPLEX RUBBER FOAM

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NUMERICAL SIMULATION OF QUASI-STATIC COMPRESSION ON A COMPLE...

Gamma radiation induced compressive response of silicon rubber foam: Experiments and modeling

中国力学大会-2017暨庆祝中国力学学会成立60周年大会

作者： huyi Wang Wenjun hu Fengpeng Zhao Institute of Systems Engineering CAEP

A complex rubber foam under quasi-static compression is numerically simulated by finite element method(FEM). Uniaxial compression is firstly tested on the base material. The obtained test data are used to calculate the parameters for the phenomenological constitutive model. Then computerized tomography(CT) technique is utilized to reconstruct the real complex foam structure. After implanting the phenomenological constitutive model into ABAQUS, simulation is done on the foam structure under quasi-static compression. The present FEM results are compared with those obtained by the multi-scale simulation and the experiments, and good agreements are achieved.

关键词： complex rubber foam quasi-static compression

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Gamma radiation induced compressive response of silicon rubb...

硅橡胶泡沫材料与刚性面准静态摩擦接触数值分析研究

中国力学大会（CCTAM2019）

作者： huyi Wang Yong Qiu Wenjun hu Yongmei Chen Institute of Systems Engineering CAEP Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province

Utilizing the experimental and numerical approaches, the gamma radiation induced compressive response of the silicon rubber foams under quasi-static compression are investigated. In the experimental research, the quasi-static compression is carried out on the samples of the silicon rubber and the silicon rubber foam. Both the samples are next exposed to the gamma radiation dose of 500 kGy with the dose rate of 100 Gy/min. The data comparison reveals that the gamma radiation hardens the samples. As the nominal strain is 20%, the compressive stresses of the rubber and the rubber foam both increase over 5 times after the gamma radiation. In the present work, a multi-scale method combined with finite element method is developed to numerically predict the compressive response of the silicon rubber foam before and after the gamma radiation. The micro-scale model is constructed according to the real micro-structures of the silicon rubber foam. Its stress and strain relationship is then simulated by using the phenomenological constitutive models, which are setup based on the testing data of the silicon rubber before and after the gamma radiation. Simulation results show that the gamma radiation strongly affect the compressive response of the micro-scale model. Based on the mechanical behaviors of the micro-scale model, the macro-scale models of the silicon rubber foam are investigated numerically. Results also reveal that the gamma radiation obviously increases the compressive stress. The obtained simulation results agree with the testing data well, which verifies the developed method. The present work develops a new method to predict the gamma radiation effects on mechanical properties of rubber foams.

关键词： gamma radiation compressed rubber foams quasi-static

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机械强度 2018年第6期40卷 1490-1494页

作者：王沪毅胡文军邱勇中国工程物理研究院总体工程研究所绵阳621999

基于有限元方法模拟研究硅橡胶泡沫材料与刚性接触面在准静态摩擦接触过程中的力学性能。基于多尺度方法建立与实际泡孔结构相符的细观模型-单胞泡孔模型。考虑泡孔壁之间摩擦因素,计算获得细观模型的力学性能。将细观模型性能通过数据... 详细信息

基于有限元方法模拟研究硅橡胶泡沫材料与刚性接触面在准静态摩擦接触过程中的力学性能。基于多尺度方法建立与实际泡孔结构相符的细观模型-单胞泡孔模型。考虑泡孔壁之间摩擦因素,计算获得细观模型的力学性能。将细观模型性能通过数据传递机制植入宏观模型,据此模拟研究硅橡胶泡沫材料与刚性加载面相互作用时的压缩载荷和结构变形情况,并讨论界面摩擦因数对该材料力学性能的影响。模拟结果表明,摩擦因数对硅橡胶泡沫材料的准静态单轴压缩力学性能影响较小,且所得模拟结果与实验结果吻合良好。

关键词：有限元硅橡胶泡沫材料刚性接触面摩擦接触多尺度

数值模拟中细观泡孔构型对硅橡胶泡沫材料力学性能的影响

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材料科学与工程学报 2019年第1期37卷 112-116页

作者：王沪毅胡文军尹益辉中国工程物理研究院总体工程研究所四川绵阳621999

基于有限元方法模拟准静态单轴压缩过程中硅橡胶泡沫材料的力学响应,并基于硅橡胶泡沫材料的泡孔特征,建立具有均匀分布且球孔尺寸一致的周期性物理模型,采用多尺度结合有限元数值方法进行模拟。根据已有的实验数据,拟合了实体硅橡胶材... 详细信息

基于有限元方法模拟准静态单轴压缩过程中硅橡胶泡沫材料的力学响应,并基于硅橡胶泡沫材料的泡孔特征,建立具有均匀分布且球孔尺寸一致的周期性物理模型,采用多尺度结合有限元数值方法进行模拟。根据已有的实验数据,拟合了实体硅橡胶材料的唯像本构方程。多尺度模拟研究中,建立了四种不同的细观泡孔单元,模拟了四种细观泡孔单元在准静态单轴压缩条件下的力学响应。模拟结果表明,四种细观泡孔单元均具有典型的超弹性力学特性,不同泡孔构型能造成细观模型力学响应的显著差异,四种细观泡孔单元中应力最大差值超过300%。细观模型的力学性能通过数据传递机制传输到均匀化的宏观模型后,采用有限元方法对宏观模型进行数值模拟。结果表明:宏观模型具有典型的超弹性力学特性,不同的细观泡孔构型能导致宏观模型力学响应的显著差异,其中应力最大差值超过300%。

关键词：有限元准静态单轴压缩硅橡胶泡沫多尺度模拟