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Early performance of two tropical dry forest species after assisted migration to pine-oak forests at different altitudes:strategic response to climate change

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Journal of Forestry Research 2020年第4期31卷 1215-1223页

作者： Pilar angélica gómez-Ruiz Cuauhtémoc sáenz-Romero Roberto Lindig-Cisneros Catedrática CONACYT Centro de Investigaciónde Ciencias Ambientales CICAFacultad de Ciencias NaturalesUniversidad Autónoma del CarmenCiudad del CarmenCampecheMexico Instituto de Investigaciones Agropecuarias y Forestales Universidad Michoacana de San Nicolás de Hidalgo(IIAFUMSNH)MoreliaMexico Instituto de Investigaciones en Ecosistemas y sustentabilidad(IIEs) Universidad Nacional Autónoma de MéxicoCampus MoreliaMoreliaMexico

Assisted migration has been proposed as a strategy for adaptive management of forest species in response to expected effects of climate change,but it is controversial for several *** dry forests are among the most threatened ecosystems in the *** Mexico,historically,land-use change and deforestation have been decreasing forest cover,and climate change is shifting the potential distribution of different forest types,exacerbating the risk of local *** altitudinal migration could be a feasible strategy for reducing local extinctions in response to climate change and lack of landscape *** objective was to evaluate survival and growth of Albizia plurijuga and Ceiba aesculifolia,two tropical deciduous forests species in *** transplanted 4-month-old seedlings to experimental raised beds at three altitudes(2100,2400 and 2700 m a.s.l.),exceeding their upper regional limit of distribution(2000 m a.s.l.).We also tested seed germination at each *** monitored the experiment for 10 *** both species,as altitude increased and cold weather was more prevalent,plant performance *** species,differences in individual growth were significant among *** survival was 18.5%for *** and 24.5%for *** species had higher survival and better growth at lower altitude,and no seedling emergence at any *** conclude that assisted migration can be implemented for each species by an upward attitudinal shift within,and not exceeding,400 m beyond their present upper altitudinal limit of *** results indicate that for many species that show altitudinal gradients at regional scales,unless current climate conditions change,the potential to establish outside their range is minimal.

关键词： Albizia plurijuga Ceiba aesculifolia Climate change Fabaceae Forest management Mitigation strategy Range expansion

A micromechanical model based on hypersingular integro-differential equations for analyzing micro-crazed interfaces between dissimilar elastic materials

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 193-206页

作者： X.Wang W.T.ang h.FAN school of Mechanical and Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore

The current work models a weak(soft) interface between two elastic materials as containing a periodic array of micro-crazes. The boundary conditions on the interfacial micro-crazes are formulated in terms of a system of hypersingular integro-differential equations with unknown functions given by the displacement jumps across opposite faces of the micro-crazes. Once the displacement jumps are obtained by approximately solving the integro-differential equations, the effective stiffness of the micro-crazed interface can be readily computed. The effective stiffness is an important quantity needed for expressing the interfacial conditions in the spring-like macro-model of soft interfaces. specific case studies are conducted to gain physical insights into how the effective stiffness of the interface may be influenced by the details of the interfacial micro-crazes.

关键词： micromechanical modeling micro-crazed interface effective stiffness coefficient hypersingular integro-differential equation

An Overview of self-piercing Riveting Process with Focus on Joint Failures, Corrosion Issues and Optimisation Techniques

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Chinese Journal of Mechanical Engineering 2021年第1期34卷 89-113页

作者： hua Qian ang school of Engineering RMIT UniversityBundooraVictoria 3083Australia

self-piercing riveting(sPR)is a cold forming technique used to fasten together two or more sheets of materials with a rivet without the need to predrill a *** application of sPR in the automotive sector has become increasingly popular mainly due to the growing use of lightweight materials in transportation ***,sPR joining of these advanced light materials remains a challenge as these materials often lack a good combination of high strength and ductility to resist the large plastic deformation induced by the sPR *** this paper,sPR joints of advanced materials and their corresponding failure mechanisms are discussed,aiming to provide the foundation for future improvement of sPR joint *** paper is divided into three major sections:1)joint failures focusing on joint defects originated from the sPR process and joint failure modes under different mechanical loading conditions,2)joint corrosion issues,and 3)joint optimisation via process parameters and advanced techniques.

关键词： self-piercing riveting Mechanical joining Joint defects Failure mechanisms Corrosion Joint optimisation

Refining constitutive relation by integration of finite element simulations and gleeble experiments

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Journal of Materials science & Technology 2019年第6期35卷 1039-1043页

作者： D.J. Yu D.s. Xu h. W ang Z.B. Zhao g.Z. Wei R. Yang College of sciences Northeastern University Shenyang 110004 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

Thermo-mechanical coupled finite element calculations were carried out to simulate the gleeble compression of the samples of a titanium alloy(Ti60), and the results are analyzed and compared with the actual compression tests conducted on a gleeble 3800 thermo-mechanical simulator. The changes in temperature, stress and strain distribution in the samples and the source of error on the constitutive relations from gleeble hot compression test were analyzed in detail. Both simulations and experiments showed that the temperature distribution in the specimen is not uniform during hot compression, resulting in significant deformation inhomogeneity and non-ignorable error in the flow stress strain relation,invalidating the uniform strain assumption commonly assumed when extracting the constitutive relation from gleeble tests. Based on the finite element simulations with iterative corrections, we propose a scheme to refine the constitutive relations from gleeble tests.

关键词： Titanium alloy Constitutive relation Finite element Compression Temperature distribution

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数字经济、创新能力与经济高质量发展

江苏商论 2025年第1期 22-27,36页

作者：臧守芳盐城师范学院数学与统计学院盐城数字经济研究院数字金融研究所江苏盐城224002

当前,中国经济已经由高速发展转向高质量发展,数字经济作为经济发展的新动能,正成为推动经济高质量发展的重要引擎。文章基于2011—2019年省级面板数据,通过构建综合评价指标体系,利用固定效应模型,从创新视角出发,探究数字经济影响高... 详细信息

当前,中国经济已经由高速发展转向高质量发展,数字经济作为经济发展的新动能,正成为推动经济高质量发展的重要引擎。文章基于2011—2019年省级面板数据,通过构建综合评价指标体系,利用固定效应模型,从创新视角出发,探究数字经济影响高质量发展的内在机制。结果表明,数字经济有效推动了经济高质量发展;创新能力在其中发挥了正向调节作用。这种影响作用存在区域异质性,中西部地区相较于东部地区更为明显。因此,文章提出了加强科技创新,持续推进数字产业化和产业数字化建设,施行差异化数字转型策略,并加强风险防范的建议。

关键词：创新能力数字经济高质量发展

Role of interstitial flow in tumor migration through 3D ECM

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Acta Mechanica sinica 2020年第3期36卷 768-774页

作者： ang Li Ren sun MOE Key Laboratory of hydrodynamics School of Naval ArchitectureOcean&Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Cancer invasion in tissue is simultaneously regulated by chemical and mechanical *** suggest that interstitial flow plays a critical role in tumor *** one hand,the distribution of chemokines around cell is influenced by *** the other hand,interstitial flow may reconfigure the alignment of fiber matrix,which greatly changes the contact force between cell and extracellular *** this study,we have upgraded a model by which we can quantitatively investigate the influence of flow on tumor cell migration.A hydrodynamic analysis of shear stress on a slender body is introduced to simulate the fiber *** such as subtle flow and cell-matrix interaction which dominate tumor migration are integrated in this novel *** results show interstitial flow facilitates tumor cell migration in the flow ***,the flow-related chemical and mechanical cues have a synergistic effect on the *** model provides better understanding on cancer metastasis and helps design vitro experiment precisely.

关键词： Interstitial flow Tumor cell migration Extracellular matrix

gradient structured Copper by Rotationally Accelerated shot Peening

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Journal of Materials science & Technology 2017年第7期33卷 758-761页

作者： X.Wang Y.s.Li Q.Z.ang Y.h.Zhao Y.T.Zhu Nano structural Materials Center School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China school of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Materials science and Engineering North Carolina State University Raleigh NC 27695 USA

A new technology-rotationally accelerated shot peening（RAsP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RAsP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RAsP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RAsP technology and other established techniques in preparing gradient structured materials is discussed. The RAsP technology exhibits a promoting future for large-scale manufacturing of gradient materials.

关键词： Microstructure Rotationally accelerated shot peening gradient structure hardness Copper

sYNThEsIs AND ChARACTERIZATION OF A NOVEL POLYMER ELECTROLYTE BAsED ON ACRYLONITRILE/N-[4-(AMINOsULFONYL)PhENYL]ACRYLAMIDE COPOLYMERs

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Chinese Journal of Polymer science 2010年第1期28卷 129-135页

作者： ang-ran Wang 包永忠 state Key Laboratory of Chemical Engineering Zhejiang University

Acrylonitrile/N-[4-（aminosulfonyl）phenyl]acrylamide （AN/AsPAA） copolymers were synthesized and used as a host of lithium ion conducting electrolytes. The composition, molecular weight and molecular weight distribution of AN/AsPAA copolymers were determined, and the influence of copolymer composition on the glass temperature of AN/AsPAA copolymers and the ion conductivity of electrolytes were investigated. The molecular weights of AN/AsPAA copolymers were lower than those of AN and AsPAA homopolymers due to the cross-termination reaction. The glass temperatures of AN/AsPAA copolymers increased as the molar fraction of AsPAA units in copolymers increased. The lithium ion conductivities of the polymer electrolytes increased initially as the molar fraction of AsPAA units in copolymers increased, and a maximum conductivity was achieved when the molar fraction of AsPAA in the copolymer was 16.8%.

关键词： Acrylonitrile N-[4-(aminosulfonyl)phenyl]acrylamide Copolymerization Composition Polymer electrolyte

stepping up after spinal cord injury:negotiating an obstacle during walking

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Neural Regeneration Research 2025年第7期20卷 1919-1929页

作者： Alain Frigon Charly g.Lecomte Department of Pharmacology-Physiology Faculty of Medicine and Health SciencesUniversitéde SherbrookeCentre de recherche du Centre Hospitalier Universitaire de SherbrookeSherbrookeQCCanada

Every day walking consists of frequent voluntary modifications in the gait pattern to negotiate *** spinal cord injury,stepping over an obstacle becomes *** over an obstacle requires sensorimotor transformations in several structures of the brain,including the parietal cortex,premotor cortex,and motor *** information and planning are transformed into motor commands,which are sent from the motor cortex to spinal neuronal circuits to alter limb trajectory,coordinate the limbs,and maintain *** spinal cord injury,bidirectional communication between the brain and spinal cord is disrupted and animals,including humans,fail to voluntarily modify limb trajectory to step over an ***,in this review,we discuss the neuromechanical control of stepping over an obstacle,why it fails after spinal cord injury,and how it recovers to a certain extent.

关键词： biomechanics locomotion neurophysiology obstacle negotiation spinal cord injury