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Active Nematodynamics on Curved Surfaces–The influence of Geometric Forces on Motion Patterns of Topological Defects

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Communications in Computational Physics 2022年第3期31卷 947-965页

作者： Michael Nestler Axel voigt institut fur wissenschaftliches Rechnen TU Dresden01062 DresdenGermany Center for Systems Biology Dresden(CSBD) Pfotenhauerstraße 10801307 DresdenGermany Cluster of Excellence Physics of Life(PoL) 01062 DresdenGermany

We derive and numerically solve a surface active nematodynamics *** validate the numerical approach on a sphere and analyse the influence of hydro-dynamics on the oscillatory motion of topological *** ellipsoidal surfaces the influence of geometric forces on these motion patterns is addressed by taking into ac-count the effects of intrinsic as well as extrinsic curvature *** numerical experiments demonstrate the stronger coupling with geometric properties if extrinsic curvature contributions are present and provide a possibility to tuneflow and defect motion by surface properties.

关键词： Topological active matter defect dynamics hydrodynamic coupling surfacefinite elements

Tensile strength and damage of open-cell ceramic foams under cylindrical splitting test

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Journal of Advanced Ceramics 2023年第11期12卷 2003-2016页

作者： Yajie Dai Jana Hubálková Claudia voigt Martin Abendroth Xiong Liang Wen Yan Yawei Li Christos G.Aneziris State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081China institute of Ceramics Refractories and Composite MaterialsTU Bergakademie FreibergFreiberg 09599Germany institute of Mechanics and Fluid Dynamics TU BergakademieFreibergFreiberg 09599Germany National–provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology Wuhan 430081China

To widen the understanding of tensile failure of reticulated ceramic foams and expand the available mechanical method,a cylindrical splitting test is developed in the present study based on alumina open-cell foams of three different pore *** biaxial method is validated by characterization of mechanical parameters,and the in-situ fracture process is validated by a digital image correlation,followed by a formula correction for effective tensile strength with consideration of discrete crack *** experimental setup curved loading platens,compliant pad and intermediate quasi-static loading rate are proposed for guaranteeing tensile failure under a radial compressive *** strength,fracture energy,and brittleness increase with the foam pore density,and the fracture behavior is a balanced result of materials and foam structural support *** analytical model of splitting tensile strength with structural parameters is derived,which implies its dependence on cell size and critical stress intensity factor of strut materials.

关键词： cylindrical splitting test mechanical behavior structural parameters alumina ceramic foams digital image correlation

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含分段阻尼特性动力吸振器的吸振性能

振动工程学报 2024年第6期37卷 945-953页

作者：卢学礼邢海军阮子悦石家庄铁道大学机械工程学院河北石家庄050043

利用凸轮机构设计了一种分段阻尼装置。以传统voigt型动力吸振器为基础,将该装置安装于动力吸振器的主系统与子系统之间,建立了吸振器的动力学方程。利用在一个振动周期内阻尼耗能等效这一原理,在相同振动频率下得到了分段阻尼装置的等... 详细信息

利用凸轮机构设计了一种分段阻尼装置。以传统voigt型动力吸振器为基础,将该装置安装于动力吸振器的主系统与子系统之间,建立了吸振器的动力学方程。利用在一个振动周期内阻尼耗能等效这一原理,在相同振动频率下得到了分段阻尼装置的等效阻尼系数。推导得出了具有分段阻尼特性的动力吸振器的理论解,并用数值解进行了验证。比较分析了无阻尼、传统线性阻尼及具有分段阻尼特性的动力吸振器的吸振特性。结果表明,具有分段阻尼特性的动力吸振器的幅频特性综合了无阻尼和传统线性阻尼动力吸振器的特点,能保证反共振点处主系统的振幅很低,同时对主系统的共振振幅的抑制效果接近于传统线性阻尼动力吸振器。

关键词：动力吸振器分段阻尼共振反共振能量等效

On the laboratory rearing of green dock leaf beetles Gastrophysa viridula （Coleoptera： Chrysomelidae）

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insect Science 2011年第3期18卷 379-384页

作者： Dagmar voigt Naoe Hosoda Jan Schuppert Stanislav Gorb Evolutionary Biomaterials Group Department of Thin-Films and Biological Systems Max Planck Institute for Metals Research Stuttgart Department of Functional Morphology and Biomechanics Zoological Institute Christian Albrechts University of Kiel Kiel Germany Advanced Nano Materials Laboratory Interconnect Design Group National Institute for Materials Tsukuba Ibaraki Japan

Leaf beetles Gastrophysa viridula have attracted recently increased research interest from various points of view, since they are：（i） pest insects in rhubarb crops; （ii） potential biocontrol agents of dock plants Rumex spp. in grasslands; and （iii） a model species in ecological studies on insect population dynamics, biochemistry, behavior, biomechanics and biomimetics. The continuous rearing of beetles at standardized conditions may help to unify the fitness state of different individuals, allowing a better comparison of experimental results. The present communication suggests a modular space- and time-saving rearing method ofG. viridula in stackable faunariums under laboratory conditions, which has been successfully established and continuously used over the last 5 years. Several developmental stages were kept in separate boxes, and multiple generations were kept simultaneously, depending on the required number of beetles.

关键词： Chrysomelidae standardisation Rumex obtusifolius

Closing the gap between atomic-scale lattice deformations and continuum elasticity

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npj Computational Materials 2019年第1期5卷 737-745页

作者： Marco Salvalaglio Axel voigt Ken R.Elder institute of Scientific Computing Technische Universität Dresden01062 DresdenGermany Dresden Center for Computational Materials Science(DCMS) TU Dresden01062 DresdenGermany Department of Physics Oakland UniversityRochesterMI 48309USA

Crystal lattice deformations can be described microscopically by explicitly accounting for the position of atoms or macroscopically by continuum *** this work,we report on the description of continuous elastic fields derived from an atomistic representation of crystalline structures that also include features typical of the microscopic *** expressions for strain components are obtained from the complex amplitudes of the Fourier modes representing periodic lattice positions,which can be generally provided by atomistic modeling or *** magnitude and phase of these amplitudes,together with the continuous description of strains,are able to characterize crystal rotations,lattice deformations,and ***,combined with the so-called amplitude expansion of the phase-field crystal model,they provide a suitable tool for bridging microscopic to macroscopic *** study enables the in-depth analysis of elasticity effects for macroscale and mesoscale systems taking microscopic details into account.

关键词： lattice elasticity macroscopic

Geometric Evolution Laws for Thin Crystalline Films: Modeling and Numerics

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Communications in Computational Physics 2009年第8期6卷 433-482页

作者： Bo Li John Lowengrub Andreas Ratz Axel voigt Department of Mathematics and Center for Theoretical Biological Physics University of California at San DiegoLa JollaCA 92093-0112USA Department of Mathematics University of California at IrvineIrvineCA 92697-3875USA institut fur Wissenschaftliches Rechnen Technische Universitat Dresden01062 DresdenGermany Department of Physics Technical University of Helsinki02015 EspooFinland.

Geometrical evolution laws are widely used in continuum modeling of surface and interface motion in materials *** this article,we first give a brief review of various kinds of geometrical evolution laws and their variational derivations,with an emphasis on strong *** then survey some of the finite element based numerical methods for simulating the motion of interfaces focusing on the field of thin film *** discuss the finite element method applied to front-tracking,phase-field and level-set *** describe various applications of these geometrical evolution laws to materials science problems,and in particular,the growth and morphologies of thin crystalline films.

关键词： interface problems geometric evolution laws anisotropy kinetics front tracking level-set phase-field chemical vapor deposition molecular beam epitaxy liquid phase epitaxy electrodeposition

Migratory flight imposes oxidative stress in bats

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Current Zoology 2019年第2期65卷 147-153页

作者： David COSTANTiNi Oliver LiNDECKE Gunars PETERSONS Christian C. voigt UMR 7221 CNRS/MNHN Museum National d'Histoire Naturelle Sorbonne Universites 7 rue Cuvier Paris 75005 France Department of Biology University of Antwerp Universiteitsplein 1 Antwerp 2610 Belgium Department of Evolutionary Ecology Leibniz Institute for Zoo and Wildlife Research Alfred-Kowalke-StraBe 17 Berlin 10315Germany lnstitute of Biology Freie Universitat Berlin Takustr. 6 Berlin 14195 Germany Faculty of Veterinary Medicine Latvia University of Life Sciences and Technologies K. Helmaqa & Jelgava LV 3004 Latvia

Many animal species migrate over long distances, but the physiological challenges of migration are poorly understood. it has recently been suggested that increased molecular oxidative damage might be one important challenge for migratory animals. We tested the hypothesis that autumn migration imposes an oxidative challenge to bats by comparing values of 4 blood-based markers of oxidative status (oxidative damage and both enzymatic and nonenzymatic antioxidants) between Nathusius' bats Pipistrellus nathusii that were caught during migration flights with those measured in conspecifics after resting for 18 or 24 h. Experiments were carried out at Pape Ornithological Station in Pape (Latvia) in 2016 and 2017. Our results show that flying bats have a blood oxidative status different from that of resting bats due to higher oxidative damage and different expression of both non enzymatic and enzymatic antioxidants (glutathione peroxidase). The differences in oxidative status markers varied betwee n sampli ng years and were in depende nt from in dividual body con dition or sex. Our work provides evidence that migratory flight might impose acute oxidative stress to bats and that resting helps animals to recover from oxidative damage accrued en route. Our data suggest that migrating bats and birds might share similar strategies of mitigating and recovering from oxidative stress.

关键词： antioxidants mammals oxidative damage stopover stress

The Global Value Chains in BRiCS Countries

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Fudan Journal of the Humanities and Social Sciences 2014年第3期7卷 411-420页

作者： Ming Ye S. voigt Center for BRiCS Studies Fudan University Room 914 West Wing Guanghua Building220 Handan Road Shanghai China Centre for European Economic Research (ZEW) Mannheim Germany

This paper provides indicators on the length, location, and linkages of global value chains (GVCs) across BRiCS countries. These indicators are calculated at the country level using the WiOD database. We find that, as Chinese GVCs lengthen, production stages are increasingly concentrated in China. At the same time, the “upstreamness” of Chinese production stages in GVCs is also increasing. Compared with China, other BRiCS countries’ positions in GVCs remain relatively unchanged. Since 2000, a new phenomenon has emerged; i.e., some service sectors within the BRiCS have begun to participate in GVCs.

关键词：价值链金砖生产阶段服务行业中国数据库位置

Wireless Communication over ZigBee for Automotive inclination Measurement

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China Communications 2008年第3期5卷 140-144页

作者： Marco Diene Sebastian voigt Jan Mehner Thomas Gessner Department for Microsystems and Precision Engineering Chemnitz University of Technology Center for Microtechnologies Chemnitz University of Technology

With the ongoing development of microsystem technologies,sensors become smaller and *** is a low rate and low power WPAN for short range communication,which is particularly aimed at sensing and control *** data from many sensors can be read via ZigBee wireless communication for *** actors might be driven via ZigBee as *** this paper,a microcontroller HCS08 from Freescale gathers the inclination sensor’s data through interface *** then the MCU controls MC13192 RF data modem through SPi interface to transmit these *** RF iC receives the data,and the inclination angle is visually shown on the PC monitor in LabView~.in the end,the experiment was done.

关键词： ZigBee iEEE 802.15.4 vehicle sensor network sensor node