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Rigidity of subfamilies of hypersurfaces in P^n with maximal length of Griffiths-Yukawa coupling

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Science China Mathematics 2014年第7期57卷 1419-1426页

作者： peng fan Department of Mathematics East China Normal University

Let f ： X → U be a family of smooth hypersurfaces in P nof degree d ＆gt; n＋1 over a smooth curve *** that the Griffiths-Yukawa coupling of f is *** f is ***,we generalize it to the case when the Griffiths-Yukawa c... 详细信息

关键词： families of hypersurfaces Griffiths-Yukawa coupling Higgs bundle variation of Hodge structures

Fourth-order phase-field modeling for brittle fracture in piezoelectric materials

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 837-856页

作者： Yu TAN fan peng Chang LIU Daiming peng Xiangyu LI State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Science Chang'an UniversityXi'an 710064China Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Failure analyses of piezoelectric structures and devices are of engineering and scientific *** this paper,a fourth-order phase-field fracture model for piezoelectric solids is developed based on the Hamilton *** typical electric boundary conditions are involved in the present model to characterize the fracture behaviors in various physical situations.A staggered algorithm is used to simulate the crack *** polynomial splines over hierarchical T-meshes(PHT-splines)are adopted as the basis function,which owns the *** numerical simulations are performed to study the influence of the electric boundary conditions and the applied electric field on the fracture behaviors of piezoelectric *** electric boundary conditions may influence crack paths and fracture loads *** present research may be helpful for the reliability evaluation of the piezoelectric structure in the future applications.

关键词： isogeometric analysis(IGA) brittle fracture fourth-order phase-field model piezoelectric solid

Controllable precision of the projective truncation approximation for Green's functions

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Chinese Physics B 2019年第4期28卷 317-325页

作者： peng fan Ning-Hua Tong Department of Physics Renmin University of China

Recently, we developed the projective truncation approximation for the equation of motion of two-time Green's functions(fan et al., Phys. Rev. B 97, 165140(2018)). In that approximation, the precision of results depends on the selection of operator basis. Here, for three successively larger operator bases, we calculate the local static averages and the impurity density of states of the single-band Anderson impurity model. The results converge systematically towards those of numerical renormalization group as the basis size is enlarged. We also propose a quantitative gauge of the truncation error within this method and demonstrate its usefulness using the Hubbard-I basis. We thus confirm that the projective truncation approximation is a method of controllable precision for quantum many-body systems.

关键词： projective truncation approximation two-time Green’s functions single-band Anderson impurity model numerical renormalization group

Extant primates and development of primatology in China: Publications, student training, and funding

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Zoological Research 2018年第4期39卷 249-254页

作者： peng-Fei fan Chi Ma School of Life Sciences Sun Yat-Sen University

China supports the richest non-human primate diversity in the northern hemisphere, providing an excellent opportunity for Chinese primatologists to take a leading role in advancing the study of primatology Primatology in China began to flourish after 1979. To date, Chinese primatologists have published more than 1 000 papers in journals indexed by the Chinese Science Citation Database and the Web of Science Core Collection, and universities and academic institutions have trained 107 PhD students and 370 Masters students between 1984 and 2016. In total, the National Science Foundation of China has funded 129 primate projects （RMB 71.7 million） supporting 59 researchers from 28 organizations. However, previous research has also shown obvious species bias. Rhinopithecus roxellana, Rhinopithecus bieti, and Macaca mulatta have received much greater research attention than other species. Researchers have also tended to continue to study the same species （55.2%） they studied during their PhD training. To promote the development of primatology in China, we suggest （1） the need for a comprehensive primatology textbook written in Chinese, （2） continued training of more PhD students, and （3） encouragement to study less well-known primate species.

关键词： Gibbon Snub-nosed monkey Leafmonkey Macaque Slow Iories

On the durable critic load in creep buckling of viscoelastic laminated plates and circular cylindrical shells

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Science China(Physics,Mechanics & Astronomy) 2008年第7期51卷 873-882页

作者： peng fan FU YiMing LIU Yifan College of Mechanics and Aerospace Hunan UniversityChangsha 410082China

Based on the first order shear deformation theory and classic buckling theory, the paper investigates the creep buckling behavior of viscoelastic laminated plates and laminated circular cylindrical shells. The analysis and elaboration of both instantaneous elastic critic load and durable critic load are emphasized. The buckling load in phase domain is obtained from governing equations by applying Laplace transform, and the instantaneous elastic critic load and durable critic load are determined according to the extreme value theorem for inverse Laplace transform. It is shown that viscoelastic approach and quasi-elastic approach yield identical solutions for these two types of critic load respectively. A transverse disturbance model is developed to give the same mechanics significance of durable critic load as that of elastic critic load. Two types of critic loads of boron/epoxy composite laminated plates and circular cylindrical shells are discussed in detail individually, and the influencing factors to induce creep buckling are revealed by examining the viscoelasticity incorporated in transverse shear deformation and in-plane flexibility.

关键词： Viscoelasticity laminated plate and shell creep buckling instantaneous elastic critic load durable critic load transverse shear deformation

Internal Structure of Cambrian Fossil Embryo Markuelia Revealed in the Light of Synchrotron Radiation X-ray Tomographic Microscopy

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Acta Geologica Sinica(English Edition) 2011年第1期85卷 81-90页

作者： CHENG Gong peng fan DUAN Baichuan DONG Xiping School of Earth and Space Sciences Peking University Beijing 100871 China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

In the light of Synchrotron Radiation X-ray Tomographic Microscopy （SRXTM）, the internal structure of Markuelia hunanensis is revealed. In one example, vitrification and peeling show the annuli hidden under the chorion. Sectioning and 3-D reconstruction display an intact digestive tract from the inverted introvert to the terminal anus. The inverted introvert forms a rugby cavum. The following digestive tract is rope-like coiling, parallel to the body axis, about 650 μm in length, and uniform in diameter （-80 μm）. An exquisitely preserved pipe-like structure is hidden in the middle of the rope-like structure, diameter 20--40 lam, with a length of -120 μm. We interpret this pipe-like structure as the possible epidermis of the gut and its surroundings as the possible residue of musculature, similar to that in Priapulans. The two symmetrical rod-shape structures connecting the body wall and digestive tract are interpreted as the possible retractor muscles. After comparing the well preserved Left-form and Right-form Body of Markuelia, we suggest that they may represent a dimorphism. Counted directly, one sample of Markuelia hunanensis possesses 62 annulations and the other 68.

关键词： Markuelia Synchrotron Radiation X-ray Tomographic Microscopy (SRXTM),dimorphism

Mathematical and computational approaches to epidemic modeling： a comprehensive review

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Frontiers of Computer Science 2015年第5期9卷 806-826页

作者： Wei DUAN Zongchen fan peng ZHANG Gang GUO Xiaogang QIU Center of Computational Experiments and Parallel Systems Technology College of Information Systems and Management National University of Defense Technology Chang sha 410073 China

Mathematical and computational approaches are important tools for understanding epidemic spread patterns and evaluating policies of disease control. In recent years, epidemiology has become increasingly integrated with mathematics, sociology, management science, complexity science, and computer science. The cross of multiple disciplines has caused rapid development of mathematical and computational approaches to epidemic modeling. In this article, we carry out a comprehensive review of epidemic models to provide an insight into the literature of epidemic modeling and *** introduce major epidemic models in three directions, including mathematical models, complex network models, and agent-based models. We discuss the principles, applications, advantages, and limitations of these models. Meanwhile, we also propose some future research directions in epidemic modeling.

关键词： mathematics complex networks agent-basedmodels epidemic modeling human dynamics infectious diseases

Strain Softening of Styrene-Isoprene-Styrene Copolymers under Large Amplitude Oscillatory Shear for Clarifying Payne Effect in Rubbers and Their Nanocomposites

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Chinese Journal of Polymer Science 2023年第1期41卷 153-165页

作者： Xin-peng fan Yi-Hu Song Qiang Zheng Wan-Jie Wang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou310027China Shanxi-Zheda Institute of New Materials and Chemical Engineering Taiyuan030000China College of Materials Science and Engineering Henan Key Laboratory of Advanced Nylon Materials and ApplicationZhengzhou UniversityZhengzhou450001China

To illustrate mechanisms of Payne effect in rubbers and their nanocomposites experiencing large amplitude oscillatory shear(LAOS),comparison studies were performed in styrene-isoprene-styrene(SIS)copolymers and their selectively crosslinked materials at temperatures below and above glass transition temperature of the polystyrene(PS)*** was found that under periodic dynamic shear,the strain softening is reversible when the polyisoprene(PI)phase,either crosslinked or not,is restricted by hard PS domains but it shows hysteresis once the PS domains *** strain softening can happen at the time scale of intrinsic Rouse relaxation of elastically active network *** stress of strain softening scales with number density of elastically active network strands,a simple relation being verified not only in the selectively crosslinked SIS copolymers but also in PI gum vulcanizates and carbon black filled PI *** effect is traditionally used to term strain softening of highly filled rubber vulcanizates under LAOS deformation while evidenced herein is that the Payne effect of highly filled rubber vulcanizates shares the mechanism being common to the strain softening of SIS copolymers.

关键词： Large amplitude oscillatory shear SIS Rubber nanocomposites Strain softening

Advances in microfluidic chips based on islet hormone-sensing techniques

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World Journal of Diabetes 2023年第1期14卷 17-25页

作者： Wei Li You-fan peng Department of Endocrinology Suzhou Hospital of Anhui Medical UniversitySuzhou 234000Anhui ProvinceChina Department of Respiratory and Critical Care Medicine The Affiliated Hospital of Youjiang Medical University for NationalitiesBaise 533000Guangxi Zhuang Autonomous RegionChina

Diabetes mellitus is a global health problem resulting from islet dysfunction or insulin *** mechanisms of islet dysfunction are still under *** hormone secretion is the main function of islets,and serves an important role in the homeostasis of blood *** the detailed mechanism of islet hormone secretome distortion can provide clues for the treatment of ***,it is crucial to develop accurate,real-time,laborsaving,high-throughput,automated,and cost-effective techniques for the sensing of islet *** chips,an elegant platform that combines biology,engineering,computer science,and biomaterials,have attracted tremendous interest from scientists in the field of diabetes *** tiny devices are miniatures of traditional experimental systems with more advantages of timesaving,reagent-minimization,automation,high-throughput,and online *** features of microfluidic chips meet the demands of islet secretome analysis and a variety of chips have been designed in the past 20 *** this review,we present a brief introduction of microfluidic chips,and three microfluidic chipsbased islet hormone sensing *** focus mainly on the theory of these techniques,and provide detailed examples based on these theories with the hope of providing some insights into the design of future chips or whole detection systems.

关键词： Microfluidic chips Islet hormone Secretome Diabetes Sensing