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Friction 2014年第4期2卷 310-316页

作者： Anatolii BABUTSKYI andreas CHRYSANTHOU Chuanli ZHAO School of Engineering and Technology University of HertfordshireHatfieldUK

Disc specimens manufactured from commercial bearing rollers(AISI 52100 steel,62−63 HRC)in initial state and after pre‐treatment by pulsed magnetic field(PMF)with a magnetic field strength of 1−7 MA/m were tested with sunflower oil using pin‐on‐disk *** to the obtained results the treatment causes a reduction in the coefficient of friction and *** explain the results,nano‐and microhardness tests as well as optical and atomic force microscopy were *** of the effect of PMF on the friction and wear were discussed.

关键词： bearing rollers pulsed magnetic field

Live-Cell Imaging of Dual-Labeled Golgi Stacks in Tobacco BY-2 Cells Reveals Similar Behaviors for Different Cisternae during Movement and Brefeldin A Treatment

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Molecular Plant 2011年第5期4卷 896-908页

作者： Stephanie L. Madison andreas Nebenfuhr Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN 37996-0840 USA

In plant cells, the Golgi apparatus consists of numerous stacks that, in turn, are composed of several flattened cisternae with a clear cis-to-trans polarity. During normal functioning within living cells, this unusual organelle displays a wide range of dynamic behaviors such as whole stack motility, constant membrane flux through the cisternae, and Golgi enzyme recycling through the ER. In order to further investigate various aspects of Golgi stack dynamics and integrity, we co-expressed pairs of established Golgi markers in tobacco BY-2 cells to distinguish sub-compartments of the Golgi during monensin treatments, movement, and brefeldin A （BFA）-induced disassembly. A combination of cis and trans markers revealed that Golgi stacks remain intact as they move through the cytoplasm. The Golgi stack orientation during these movements showed a slight preference for the cis side moving ahead, but trans cisternae were also found at the leading edge. During BFA treatments, the different sub-compartments of about half of the observed stacks fused with the ER sequentially; however, no consistent order could be detected. In contrast, the ionophore monensin resulted in swelling of trans cisternae while medial and particularly cis cisternae were mostly unaffected. Our results thus demonstrate a re- markable equivalence of the different cisternae with respect to movement and BFA-induced fusion with the ER. In addi- tion, we propose that a combination of dual-label fluorescence microscopy and drug treatments can provide a simple alternative approach to the determination of protein localization to specific Golgi sub-compartments.

关键词： Golgi apparatus Golgi stack integrity brefeldin A monensin tobacco BY-2 cells live-cell imaging.

Energy band alignment at ferroelectric/electrode interface determined by photoelectron spectroscopy

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Chinese Physics B 2014年第1期23卷 1-16页

作者：陈峰吴文彬李舜怡 andreas Klein High Magnetic Field Laboratory Chinese Academy of Sciences (CAS) and Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China High Magnetic Field Laboratory Chinese Academy of Sciences (CAS) and Hefei National Laboratory for Physical Sciences at MicroscaleUniversity of Science and Technology of China TechnischeUniversitt Darmstadt Department of Materials and Earth Sciences

The most important interface-related quantities determined by band alignment are the barrier heights for charge trans- port, given by the Fermi level position at the interface. Taking Pb（Zr, Ti）O3 （PZT） as a typical ferroelectric material and applying X-ray photoelectron spectroscopy （XPS）, we briefly review the interface formation and barrier heights at the inter- faces between PZT and electrodes made of various metals or conductive oxides. Polarization dependence of the Schottky barrier height at a ferroelectric/electrode interface is also directly observed using XPS.

关键词： ferroelectric band alignment Schottky barrier X-ray photoelectron spectroscopy

Photoemission Spectroscopy and Electronic Structures of LiMn2O4

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Chinese Physics Letters 2006年第8期23卷 2202-2205页

作者：吴启辉 THISSEN andreas JAEGERMANN Wolfram Department of Physics and Semiconductor Photonics Research Center Xiamen University Xiamen 361005 Surface Science Institute Department of Materials Science Darmstadt University of Technology Petersenstr. 2364287 Darmstadt Germany

We study the electronic structures of LiMn2O4 by x-ray and ultraviolet photoelectron spectroscopy （XPS, UPS） and resonant photoelectron spectroscopy （RPES）. XPS data suggest that the average oxidation state of Mn ions is 3.55, probably due to the small amount of lithium oxides on the surface. UPS and RPES data imply that Mn ions are in a high spin state, and RPES results show strong Mn3d-O2p hybridization in the LiMn2O4 valence band.

关键词： RAY PHOTOELECTRON-SPECTROSCOPY PHASE-TRANSITION THIN-FILMS SPINELS LI LI(X)MN2O4 SYSTEMS CELLS

Estimation of particle dynamics in 2-D fluidized beds using particle tracking velocimetry

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Particuology 2015年第5期13卷 39-51页

作者： Thomas Hagemeier Christoph Roloff andreas Buck Evangelos Tsotsas NaWiTec Thermal Process EngineeringOtto-von-Guericke University MagdeburgUniversitaetsplatz 239106 MagdeburgGermany Fluid Dynamics and Technical Flow Otto-von-Guericke University MagdeburgUniversitaetsplatz 239106 MagdeburgGermany

The experimental characterization of particle dynamics in fluidized beds is of great importance in fostering an understanding of solid phase motion and its effect on particle properties in granulation processes, Commonly used techniques such as particle image velocimetry rely on the cross-correlation of illumination intensity and averaging procedures. It is not possible to obtain single particle velocities with such techniques. Moreover, the estimated velocities may not accurately represent the local particle velocities in regions with high velocity gradients. Consequently, there is a need for devices and methods that are capable of acquiring individual particle velocities. This paper describes how particle tracking velocimetry can be adapted to dense particulate flows. The approach presented in this paper couples high-speed imaging with an innovative segmentation algorithm for particle detection, and employs the Voronoi method to solve the assignment problem usually encountered in densely seeded fows. Lagrangian particle tracks are obtained as primary information, and these serve as the basis for calculating sophisticated quantities such as the solid-phase flow field, granular temperature, and solid volume fraction. We show that the consistency of individual trajectories is sufficient to recognize collision events.

关键词： Particle dynamics Particle tracking velocimetry Pseudo-2D Fluidized bed

Numerical Simulation of the Mechanical Properties of Sintered and Bonded Perforated Hollow Sphere Structures (PHSS)

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Journal of Materials Science & Technology 2010年第8期26卷 730-736页

作者： andreas chsner Seyed Mohammad Hossein Hosseini Markus Merkel Department of Applied Mechanics Technical University of Malaysia Centre for Mass and Mechanical Transport in Engineering Materials The University of Newcastle CallaghanNewSouth Wales 2308Australia Department of Mechanical Engineering University of Applied Sciences Aalen

This paper investigated the uniaxial mechanical properties of a new type of hollow sphere structures. For this new type, the sphere shell was perforated by several holes in order to open the inner sphere volume and surface. The mechanical properties, i.e. elastic properties and initial yield stress of perforated hollow sphere structures （PHSS） in a primitive cubic arrangement were numerically evaluated for different hole diameters and different joining techniques of the hollow spheres. The results are compared to classical configurations without perforation.

关键词： Mechanical properties Cellular material Porous structure Finite element method

Microcrack Formation During Gas Metal Arc Welding of High-Strength Fine-Grained Structural Steel

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 140-148页

作者： Christoph Heinze Thomas Michael andreas Pittner Michael Rethmeier Division 9.3 "Welding Technology" BAM Federal Institute for Materials Research and TestingUnter den Eichen 8712205 BerlinGermany Joining and Coating Technology Fraunhofer-Institute for Production Systems and Design Technology IPKPascalstraβe 8-910587 BerlinGermany

The recent development of high-performance-modified spray arc processes in gas metal arc welding due to modern digital control technology and inverter power sources enables a focused spray arc, which results in higher penetration depths and welding speed. However, rnicrocracks occurred in the weld metal while approaching the process limits of the modified spray arc, represented by a 20-mm double layer DV-groove butt-weld, These cracks were detected in structural steel exhibiting a yield strength level of up to 960 MPa and are neither dependent on the used weld power source nor a consequence of the modified spray arc process itself. The metallographic and fractographic investigations of the rather exceptional fracture surface lead to the classification of the microcracks as hot cracks, The effects of certain welding parameters on the crack probability are clarified using a statistical design of experiment. However, these microcracks do not impact the design specification for toughness in the Charpy V-notch test （absorbed energy at -40 ℃ for the present material is 30 J）.

关键词： High-strength low-alloy steel Welding Fracture Design of experiments Microcracking

Finite size specimens with cracks of icosahedral Al Pd Mn quasicrystals

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Chinese Physics B 2014年第5期23卷 404-413页

作者：杨连枝 Ricoeur andreas 何蕃民高阳 College of Science China Agricultural University College of Engineering China Agricultural University Institute of Mechanics University of Kassel Sichuan Hydropower Investment & Management Group LTD

Icosahedral quasicrystals are the most important and thermodynamically stable in all about 200 kinds of quasicrystals currently observed. Beyond the scope of classical elasticity, apart from a phonon displacement field, there is a phason displacement field in the elasticity of the quasicrystal, which induces an important effect on the mechanical properties of the material and makes an analytical solution difficult to obtain. In this paper, a finite element algorithm for the static elasticity of icosahedral quasicrystals is developed by transforming the elastic boundary value problem of the icosahedral quasicrystals into an equivalent variational problem. Analytical and numerical solutions for an icosahedral A1-Pd-Mn quasicrystal cuboid subjected to a uniaxial tension with different phonon-phason coupling parameters are given to verify the validity of the numerical approach. A comparison between the analytical and numerical solutions of the specimen demonstrates the accuracy and efficiency of the present algorithm. Finally, in order to reveal the fracture behavior of the icosahedral A1-Pd-Mn quasicrystal, a cracked specimen with a finite size of matter is investigated, both with and without phonon-phason coupling. Meanwhile, the geometry factors are calculated, including the stress intensity factor and the crack opening displacement for the finite-size specimen. Computational results reveal the importance of pbonon-phason coupling effect on the icosahedral A1-Pd-Mn quasicrystal. Furthermore, the finite element procedure can be used to solve more complicated boundary value problems.

关键词： icosahedral quasicrystals finite-size crack specimen finite element method cuboid

Self-consistent extraction of photoabsorption time delays in attosecond streak camera

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Science China(Physics,Mechanics & Astronomy) 2024年第12期67卷 8-16页

作者： Yutong Gao Hongcheng Ni andreas Becker Jian Wu State Key Laboratory of Precision Spectroscopy East China Normal UniversityShanghai 200241China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China JILA and Department of Physics University of ColoradoBoulder 80309-0440USA Chongqing Key Laboratoryof PrecisionOptics Chongqing Institute of East China Normal UniversityChongqing 4112China

Photoionization can generally be decomposed into a photoabsorption process plus a half-scattering *** streaking time delay observed in the attosecond streak camera,correspondingly,can be decomposed into a photoabsorption time delay and a continuum time *** propose a self-consistent method to account for the potential-laser coupling effect and extract the intrinsic absorption time delay,without invoking an implicit assumption of a constant continuum correction made in previous streaking *** concept is based on an iterative technique starting from an initial guess of the absorption time delay and using classical electron trajectories to consistently remove the coupling-induced momentum shift to the streak *** show that the self-consistent iterative algorithm converges quickly and is robust against different initial *** method is applied to laser-induced ionization of atoms to obtain the absorption time delay in resonant two-photon ionization and to explore possible time delays in above-threshold *** results confirm an absorption time delay linearly dependent on the ionizing pulse duration in resonant two-photon *** method is also shown to perform better than conventional methods and to identify a small negative absorption time delay(less than 2 attoseconds) in above-threshold ionization.

关键词： attosecond streak camera photoabsorption time delay photoionization

Combining High-Resolution Imaging,Deep Learning,and Dynamic Modeling to Separate Disease and Senescence in Wheat Canopies

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Plant Phenomics 2023年第2期5卷 295-312页

作者： Jonas Anderegg Radek Zenkl Achim Walter andreas Hund Plant Pathology Group Institute of Integrative BiologyETH ZurichZurichSwitzerland Crop Science Group Institute of Agricultural SciencesETH ZurichZurichSwitzerland

Maintenance of sufficiently healthy green leaf area after anthesis is key to ensuring an adequate assimilate supply for grain *** regulated age-related physiological senescence and various biotic and abiotic stressors drive overall greenness decay dynamics under field *** direct effects on green leaf area in terms of leaf damage,stressors often anticipate or accelerate physiological senescence,which may multiply their negative impact on grain ***,we present an image processing methodology that enables the monitoring of chlorosis and necrosis separately for ears and shoots(stems+leaves)based on deep learning models for semantic segmentation and color properties of vegetation.A vegetation segmentation model was trained using semisynthetic training data generated using image composition and generative adversarial neural networks,which greatly reduced the risk of annotation uncertainties and annotation *** of the models to image time series revealed temporal patterns of greenness decay as well as the relative contributions of chlorosis and ***-based estimation of greenness decay dynamics was highly correlated with scoring-based estimations(r≈0.9).Contrasting patterns were observed for plots with different levels of foliar diseases,particularly septoria tritici *** results suggest that tracking the chlorotic and necrotic fractions separately may enable(a)a separate quantification of the contribution of biotic stress and physiological senescence on overall green leaf area dynamics and(b)investigation of interactions between biotic stress and physiological *** high-throughput nature of our methodology paves the way to conducting genetic studies of disease resistance and tolerance.

关键词： Wheat enable image