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Chinese Journal of Polymer Science 2002年第2期20卷 160-170页

作者： Y. men Univ Freiburg Fak Phys D-79104 Freiburg Germany

The mechanism of tensile deformation in semi-crystalline polymers was studied based on true stress-strain curvesobtained with the aid of a video-controlled tensile set-up. The deformation is affected by both the crystalline and theamorphous phases. However, the relative weights of the two portions change with the deformation stage. At lowdeformations the coupling and coarse slips of the crystalline blocks dominate the mechanical properties, which allows thesystem to maintain a homogeneous strain distribution in the sample. As the stretching increases, at a critical strain the forcegenerated from entangled fluid portions reaches a critical value to destroy the crystallites. The dominant deformationmechanism then changes into a disaggregation - recrystallization process.

关键词： Semi-crystalline polymer Deformation mechanism Network Mechanical property

Composite Anti-Disturbance Control of Hidden Semi-Markov Jump Systems via Disturbance Observer

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Journal of Systems Science & Complexity 2023年第6期36卷 2255-2273页

作者： men Yunzhe SUN Jian National Key Lab of Autonomous Intelligent Unmanned Systems School of AutomationBeijing Institute of TechnologyBeijing100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120China

This paper focuses on the disturbance suppression issue of hidden semi-Markov jump systems leveraging composite *** system consists of a semi-Markov layer and an observed mode sequence layer,and it is subject to a matched disturbance generated by an exogenous system and a mismatched disturbance that is norm *** proposal is to design a composite controller based on a disturbance observer to counteract and attenuate the disturbances *** constructing a special Lyapunov function comparison point,the exponential stability is analyzed with the stability criterion in the form of linear matrix inequality is *** simulation examples are provided to demonstrate the practical merits of the composite controller relative to the single H_(∞)control.

关键词： Composite control disturbance observer ε-error hidden semi-Markov jump systems

Investigation of earthquake mechanisms and their impact on certain basic concepts in earthquake engineering and seismology

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Earthquake Engineering and Engineering Vibration 2002年第2期1卷 281-291页

作者： men Fulu Institute of Engineering Mechanies.China Seismological Bureau.Harbin.China

In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medium. The relationship of mantle flow to earthquakes is examined and clarified, and a new model, different from Haskell’s, is proposed for the earthquake mechanism. The proposed new model is based on the discovery that two pairs of jump stress and jump velocity will start to act from the fault plane. Records obtained directly from recent earthquakes nearby and right on the fault break show a very large velocity impulse, which verify, indirectly, the new mechanism proposed by the author. Further, at least two physical parameters that characterize the seismic intensity must be specified, because according to the discontinuous (jump) wave theory, at the earthquake source, the stress jump and the velocity jump of particle motion should act simultaneously when a sudden break occurs. The third key parameter is shown to be the break (fracture) propagation speed together with the break plane area. This parameter influences the form of the unloading time function at the source. The maximum seismic stress in and displacement of a building are estimated for two unfavorable combinations of the building and its base ground in terms of their relative rigidity. Finally, it is shown that Biot’s theory of wave propagation in fluid saturated porous media is valid only when fluid flow cannot occur.

关键词： mantle circulation flow plate motion earthquake mechanism wave propagation break (fracture) propagation unloading wave jump wave building Biot’s theory

振动疗法联合悬吊训练前交叉韧带重建后患者运动及膝关节功能的变化

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中国组织工程研究 2025年第11期29卷 2225-2230页

作者：陈文汉门杰杨伟赵小宇山西医科大学汾阳学院山西省吕梁市032200

背景:物理疗法对前交叉韧带重建术后恢复至关重要。近年来,许多医师都在优化前交叉韧带重建术后的物理康复方案,但仍然缺乏高效的前交叉韧带重建术后康复训练疗法。目的:探讨振动疗法联合悬吊训练对前交叉韧带重建患者术后运动及膝关节... 详细信息

背景:物理疗法对前交叉韧带重建术后恢复至关重要。近年来,许多医师都在优化前交叉韧带重建术后的物理康复方案,但仍然缺乏高效的前交叉韧带重建术后康复训练疗法。目的:探讨振动疗法联合悬吊训练对前交叉韧带重建患者术后运动及膝关节功能的影响。方法:纳入在上海体育大学附属体育医院就诊的80例首次行单侧前交叉韧带重建患者,按照随机数字表法将患者随机分为振动疗法组和振动疗法+悬吊训练组,每组40例。振动疗法组患者在前交叉韧带重建术后第13周开始进行振动疗法训练(每次10 min,1次/d,每周6次),振动疗法+悬吊训练组患者在前交叉韧带重建术后第13周开始进行振动疗法(每次10 min,1次/d,每周6次)联合悬吊训练(每周2次),共训练8周。训练前及训练8后,采用膝关节Lysholm评分评价膝关节功能,采用等速肌力评估训练系统评估屈膝对称性指数,采用平衡测试系统评估双侧多轴平均轨迹误差差值。结果与结论:(1)与训练前比较,两组患者训练8周后的膝关节Lysholm评分、屈膝与伸膝对称性指数均升高(P<0.05),双侧多轴平均轨迹误差差值降低(P<0.05);与振动疗法组比较,振动疗法+悬吊训练组患者膝关节Lysholm评分、屈膝与伸膝对称性指数均升高(P<0.05),双侧多轴平均轨迹误差差值降低(P<0.05);(2)结果表明,与单独进行振动疗法相比,振动疗法联合悬吊训练可显著改善前交叉韧带重建患者的膝关节功能,增加肌肉力量和对称性,提高平衡稳定性。

关键词：前交叉韧带重建振动疗法悬吊训练膝关节功能肌肉力量对称性平衡稳定性

A Stereo Matching Algorithm Based on Four-Moded Census and Relative Confidence Plane Fitting

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Chinese Journal of Electronics 2015年第4期24卷 807-812页

作者： men Yubo ZHANG Guoyin men Chaoguang LI Xiang MA Ning Collage of Computer Science and Technology Harbin Engineering University Harbin Commercial University

A four-moded Census transform stereo matching algorithm using bidirectional constraint dynamic programming and relative confidence plane fitting is proposed to solve the problems of matching quality. Using the four-moded Census transform which adds a restrictive condition replaces traditional Census transform to improve matching accuracy and mean value of all pixels intensity replaces the center pixel intensity in the Census window to solve the problem of the center pixel distortion effectively,a refined initial local matching cost can be obtained. During the disparity optimization, the difficulty of disparity computation in textureless areas is overcome by the estimated condition and defined relative confident pixels. Experiment results show that a better dense matching map can be obtained by the proposed algorithm.

关键词： Stereo matching Disparity estimation Census transform Plane fitting

A Sub-pixel Disparity Refinement Algorithm Based on Lagrange Interpolation

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Chinese Journal of Electronics 2017年第4期26卷 784-789页

作者： men Yubo ZHANG Guoyin men Chaoguang LI Xiang MA Ning College of Computer Science and Technology Harbin Engineering University Harbin Normal University

A sub-pixel disparity refinement algorithm based on Lagrange interpolation is proposed to calculate the sub-pixel disparity and the elevation of the target construction on the remote sensing image. The accurate integer matching feature points are obtained by improved affine scale invariant feature transform. A series of interpolation samples can be estimated through the three times magnification results of each feature matching point and its close neighbor pixels. The final sub-pixel deviation can be calculated by the interpolation samples. Experiment results show that a more accurate elevation information can be obtained on the remote sensing image with corrective epipolar line, and an accurate sub-pixel disparity result can be estimated without the epipolar line constraint as well.

关键词： Computer vision Remote sensing image processing Sub-pixel disparity Interpolation

DISPERSION AND TENSILE BEHAVIOR OF POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES PRODUCED VIA MELT INTERcaLATION

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Chinese Journal of Polymer Science 2003年第3期21卷 359-368页

作者： Y.men 傅强 Department of Physics Albert-Ludwigs University D-79104 Freiburg Germany Department of Polymer Science & Materials Sichuan University State Key Laboratory of Polymer Materials Engineering Chengdu 610065 China

Most of the articles on polymer nanocomposites focus on the importance of chemistry used to modify the surface of the clay, usually montmorillonite (MMT), and characterization of the nano-scale structure obtained. The role and importance of processing were also discussed recently. However, few papers concerning the correlation between morphology of MMT and mechanical properties were published. In order to understand. the tensile behavior of PP/Montmorillonite (MMT) nanocomposites better, and to further improve the reinforcement efficiency, we first prepared the PP nanocomposites via direct melt intercalation using conventional twin-screw extrusion. The dispersion and tensile property of the composites were then investigated by SEM, XRD, TEM and a video-controlled tensile set-up. The macroscopic and microscopic dispersion of MMT in PP matrix was verified by XRD and TEM, combined with SEM. The tensile properties were obtained by video-controlled tensile set-up, which gives true stress-strain curve. It was found that a partly intercalated and partly exfoliated structure (also called incomplete exfoliation) existed in the system. Though the tensile strength of PP nanocomposites is not much improved in engineering stress-strain curves, more than 20% increase of true stress was found in a true stress-strain experiment at high true strain, which indicates that only oriented silicate layers can have a big effect on tensile properties: Not only orientation of silicate platelets but also the degree of exfoliation is a key factor to determine the reinforcement efficiency. The reinforcement efficiency of MMT has been discussed based on the 'continuum' Halpin-Tsai equations. A good agreement was found between experimental data and theoretical prediction by changing N value (number of platelets per stack) which corresponding to different state of the dispersion of MMT in PP matrix.

关键词： polypropylene/montmorillonite nanocomposites dispersion orientation tensile property

Steady state equilibrium condition of npe~± gas and its application to astrophysics

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Research in Astronomy and Astrophysics 2011年第1期11卷 91-102页

作者： men-Quan Liu Center for Astrophysics University of Science and Technology of China Hefei 230026 China Institute of Theoretical Physics China West Normal University Nanchong 637002 China

The steady equilibrium conditions for a mixed gas of neutrons, protons, electrons, positrons and radiation fields （abbreviated as npe^± gas） with or without external neutrino flux are investigated, and a general chemical potential equilibrium equation μn = μp ＋ Cμe is obtained to describe the steady equilibrium at high temperatures （T 〉 10^9 K）. An analytic fitting formula of coefficient C is presented for the sake of simplicity, when neutrinos and antineutrinos are transparent. It is a simple method to estimate the electron fraction for the steady equilibrium npe^± gas that adopts the corresponding equilibrium condition. As an example, we apply this method to the GRB accretion disk and confirm that the composition in the inner region is approximately in equilibrium when the accretion rate is low. For the case with external neutrino flux, we calculate the initial electron fraction of neutrino-driven wind from the proto-neutron star model M15-l1-r1. The results show that the improved equilibrium condition makes the electron fraction decrease significantly more than the case μn = μp ＋ μe when the time is less than 5s post bounce, which may be useful for r-process nucleosynthesis models.

关键词： nuclear reactions -- nucleosynthesis weak-interaction GRB accretion disk -- neutrino-driven wind

Fractionation of Polyolefin Elastomer by a Modified SSA Technique

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Chinese Journal of Polymer Science 2022年第10期40卷 1252-1258,I0010页

作者： Xin-Tong Zhao Yong-Feng men State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China Schoolof Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

As an important part of semicrystalline polymer materials,polyolefin elastomers are widely used,and the in-depth analysis of their molecular chain structure information is of great significance to promote their rapid *** show in this work an effort in characterizing a commercial polyolefin elastomer of ethylene/1-octene copolymer by a modified successive self-nucleation and annealing(SSA)technique.A small amount of linear polyethylene was blended with the ethylene/1-octene copolymer serving as nucleation agent during *** turned out that a tiny fraction of linear polyethylene can significantly promote the crystallization of the copolymer during cooling from different annealing temperatures and increase the melting temperature of the fractions so that providing apparent methylene sequence length much closer to the real value than obtained by traditional SSA technique.

关键词： Polyolefin elastomer Ethylene-co-octene Thermal fractionation SSA Micro structure

Multifunctional conjugated polymer nanoparticles for photoacoustic-based multimodal imaging and cancer photothermal therapy

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Journal of Innovative Optical Health Sciences 2019年第3期12卷 3-15页

作者： Xiaoju men Zhen Yuan cancer Center Faculty of Health Sciences University of MacaoMacao SAR 999708P.R.China

Photoacoustic imaging(PAI)is a hybrid imaging method based on photoacoustic(PA)effects,which is able to capture the structure,function,and molecular information of biological tissues with high *** date,therapeutic techniques under the guidance of PAI have provided new strategies for accurate diagnosis and precise treatment of *** particular,conjugated polymer nanoparticles have been extensively inspected for PA-based cancer theranostics largely due to their superior optical properties such as tunable spectrum and large absorption coefficient and their good biocompatibility,and abundant functional *** mini-review mainly focuses on the recent advances toward the development of novel conjugated polymer nanoparticles for PA-based multimodal imaging and cancer photothermal therapy.

关键词： Conjugated polymer nanoparticles photoacoustic imaging photothermal therapy multimodal imaging