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arXiv 2019年

作者： Wei, Chaozhen Zhang, Luchan Han, Jian Srolovitz, David J. Xiang, Yang Department of Mathematics Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Hong Kong Institute for Advanced Study Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Hong Kong Department of Materials Science and Engineering University of Pennsylvania PhiladelphiaPA19104-6272 United States Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA19104-6272 United States Department of Materials Science and Engineering City University of Hong Kong Hong Kong Hong Kong

The microstructure of polycrystalline materials consists of networks of grain boundaries (GBs) and triple junctions (TJs), along which three GBs meet. The evolution of such microstructures may be driven by surface tension (capillarity), applied stresses, or other means that lead to a jump in chemical potential across the GBs. Here, we develop a model for the concurrent evolution of the GB/TJ network based upon the microscopic mechanism of motion;the motion of line defects (disconnections) in the GB that have both dislocation and step character. The evolution involves thermally-activated disconnection formation/annihilation and migration of multiple disconnections modes/types. We propose this crystallography-respecting continuum model for the disconnection mechanism of GB/TJ dynamics derived with a variational approach based on the principle of maximum energy dissipation. The resultant TJ dynamics is reduced to an optimization problem with constraints that account for local microstructure geometry, conservation of Burgers vectors, and thermal-kinetic limitations on disconnection fluxes. We present analysis of and numerical simulations based upon our model to demonstrate the dependence of the GB and TJ mobilities and the TJ drag effect on the disconnection properties, and compare the predictions with molecular dynamics and experimental *** Codes 35Q74, 74K30, 74E15, 74P10, 49N10, 49S05 Copyright © 2019, The Authors. All rights reserved.

关键词： Grain boundaries

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Corrosion behavior of 304L stainless steel concrete reinforcement in acid rain using fly ash as corrosion inhibitor

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Procedia Structural Integrity 2018年 10卷 41-48页

作者： S. Tsouli A.G. Lekatou S. Kleftakis T.E. Matikas P.T. Dalla Laboratory of Applied Metallurgy Department of Materials Science & Engineering University of Ioannina Ioannina 45110 Greece Mechanics Smart Sensors & Nondestructive Evaluation Laboratory Department of Materials Science & Engineering University of Ioannina Ioannina 45110 Greece

The corrosion performance of 304L stainless steel rebars in a solution simulating concrete exposed to acid rain with the addition of fly ash was studied by means of cyclic potentiodynamic polarization. Fly ash (0-25 wt.%) was added to a concrete simulating solution. 304L rebars embedded in standard concrete cubes containing 0-25 wt.% fly ash were subjected to salt spray testing for 4 m. Tensile testing of the rebars was conducted before and after 2 m of salt spraying. Although 304L showed susceptibility to localized corrosion, the positive effect of fly ash on the corrosion behavior is clearly manifested. Fly ash content of 20 wt.% in the electrolyte led to the highest corrosion resistance. Two months of salt spraying did not affect the tensile behavior of the steel.

关键词： 304L stainless steel rebars reinforced concrete fly ash acid rain cyclic polarization salt spray test tensile test

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Erratum “15.9% organic tandem solar cell with extended near-infrared absorption” [Appl. Phys. Lett. 116, 153501 (2020)]

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applied Physics Letters 2021年第21期118卷

作者： Xinjing Huang Bangjin Sun Yongxi Li Chao Jiang Dejiu Fan Jian Fan Stephen R. Forrest 1Applied Physics Program University of Michigan Ann Arbor Michigan 48109 USA 2Institute of Functional Nano and Soft Materials Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices Soochow University Suzhou Jiangsu 215123 China 3Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor Michigan 48109 USA 4Department of Physics and Material Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA

The authors regret that a related article was not cited in the original published article.1 In the first paragraph, the sentence “We introduce a surface treatme

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Generation of terahertz transients from Co2Fe0.4Mn0.6Si-Heusler-alloy/normal-metal nanobilayers excited by femtosecond optical pulses

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Physical Review Research 2021年第4期3卷 043025-043025页

作者： Sarah Heidtfeld Roman Adam Takahide Kubota Koki Takanashi Derang Cao Carolin Schmitz-Antoniak Daniel E. Bürgler Fangzhou Wang Christian Greb Genyu Chen Ivan Komissarov Hilde Hardtdegen Martin Mikulics Roman Sobolewski Shigemasa Suga Claus M. Schneider Research Centre Jülich Peter Grünberg Institute 52425 Jülich Germany Faculty of Physics University of Duisburg-Essen 47048 Duisburg Germany Institute for Materials Research Tohoku University Sendai 980-8577 Japan Center for Spintronics Research Network Tohoku University Sendai 980-8577 Japan Center for Science and Innovation in Spintronics (Core Research Cluster) Tohoku University Sendai 980-8577 Japan College of Physics National Demonstration Center for Experimental Applied Physics Education Qingdao University Qingdao 266071 China Materials Science Graduate Program University of Rochester Rochester New York 14627 USA Laboratory for Laser Energetics University of Rochester Rochester New York 14623 USA Department of Electrical and Computer Engineering University of Rochester Rochester New York 14627 USA Belarusian State University of Informatics and Radioelectronics Minsk 220013 Belarus Research Centre Jülich Ernst Ruska Centre for Microscopy and Spectroscopy with Electrons 52425 Jülich Germany Department of Physics and Astronomy University of Rochester Rochester New York 14627 USA The Institute of Scientific and Industrial Research Osaka University Ibaraki Osaka 567-0047 Japan Department of Physics University of California Davis Davis California 95616 USA

We generated pulses of electromagnetic radiation in the terahertz (THz) frequency range by optical excitation of Co2Fe0.4Mn0.6Si (CFMS)/normal-metal (NM) bilayer structures. The CFMS is a Heusler alloy showing a band gap in one spin channel and is therefore a half metal. We compared the THz emission efficiency in a systematic manner for four different CFMS/NM bilayers, where NM was either Pt, Ta, Cr, or Al. Our measurements show that the THz intensity is highest for a Pt capping. We also demonstrate the tunability of the THz amplitude by varying the magnetic field for all four bilayers. We attribute the THz generation to the inverse spin Hall effect. In order to investigate the role of the interface in THz generation, we measured the spin mixing conductance for each CFMS/NM bilayer using a ferromagnetic resonance method. We found that the spin-orbit coupling cannot completely describe the THz generation in the bilayers and that the spin transmission efficiency of the CFMS/NM interface and the spin diffusion length, as well as the oxidation of the NM layer, play crucial roles in the THz emission process.

关键词： Inverse spin Hall effect Magnetism Spin injection Spin pumping Spintronics Ferromagnetic resonance Terahertz time-domain spectroscopy

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Effect of Twin Boundary Orientation on the Mechanical Properties of Bicrystalline Copper Micropillars

SSRN

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SSRN 2019年

作者： Wei, DeAn Zaiser, Michael Feng, Zhiqiang Kang, Guozheng Fan, Haidong Zhang, Xu Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Engineering Southwest Jiaotong University Chengdu610031 China Department of Materials Science and Engineering Institute of Materials Simulation WW8 FAU University of Erlangen-Nuremberg Dr.-Mack-Str.77 Fürth90762 Germany LMEE Univ-Evry Université Paris-Saclay Evry France Department of Mechanics Sichuan University Chengdu610065 China

Twin boundaries (TBs) constitute a special type of symmetric grain boundary (GB). TBs influence plastic deformation in a complex manner. They not only act as dislocation obstacles but can also accommodate twinning dislocations (TDs) whose motion enables twin boundary migration as an alternative deformation mechanism. Exploiting this dual effect offers interesting perspectives in view of designing materials that combine high strength and ductility. In the present work,we propose a model for dislocation-TB interactions in the framework of discrete dislocation dynamics (DDD) simulations, which we use to investigate the mechanical properties of bicrystalline copper micropillars containing a TB. We systematically investigate how the compressive response depends on the orientation of the TB with respect to the micropillar cross section. The simulations show significant strengthening effects for TB orientation angles less than 45º, where the interaction between mixed dislocations and TBs plays an important *** angles larger than 45º, the interaction between screw dislocations and TB dominates, leading to weak strengthening. At 45º, dislocations on the dominant slip systems glide parallel to the TB and no strengthening is observed. © 2019, The Authors. All rights reserved.

关键词： Copper

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A multilevel dataset of microplastic abundance in the world’s upper ocean and the Laurentian Great Lakes

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Microplastics and Nanoplastics 2021年第1期1卷 1-14页

作者： Isobe, Atsuhiko Azuma, Takafumi Cordova, Muhammad Reza Cózar, Andrés Galgani, Francois Hagita, Ryuichi Kanhai, La Daana Imai, Keiri Iwasaki, Shinsuke Kako, Shin’ichro Kozlovskii, Nikolai Lusher, Amy L. Mason, Sherri A. Michida, Yutaka Mituhasi, Takahisa Morii, Yasuhiro Mukai, Tohru Popova, Anna Shimizu, Kenichi Tokai, Tadashi Uchida, Keiichi Yagi, Mitsuharu Zhang, Weiwei Research Institute for Applied Mechanics Kyushu University 6-1 Kasuga-Koen Kasuga 816-8580 Japan Training Vessel Kagoshima maru Faculty of Fisheries Kagoshima University 4-50-20 Shimoarata Kagoshima 890-0056 Japan Research Center for Oceanography Indonesian Institute of Sciences Jl. Pasir Putih 1 Ancol Timur Jakarta 14430 Indonesia Departamento de Biología University of Cadiz and European University of the Seas (SEA-EU) Instituto Universitario de Investigación Marina (INMAR) Puerto Real E-11510 Spain IFREMER Laboratoire LER/PAC immeuble Agostini ZI Furiani Bastia 20600 France Training and research Vessel Umitaka maru Tokyo University of Marine Science and Technology 4-5-7 Konan Minato-ku Tokyo 108-8477 Japan Department of Life Sciences The University of the West Indies W.I St. Augustine Campus Trinidad and Tobago School of Fisheries Sciences Hokkaido University 3-1-1 Minato-cho Hokkaido Hakodate 041-8611 Japan Civil Engineering Research Institute for Cold Region 1-3-1-34 Toyohira Sapporo 062-8602 Japan Department of Engineering Ocean Civil Engineering Program Kagoshima University Kagoshima 890-0054 Japan Pacific Geographical Institute Far Eastern Branch of Russian Academy of Sciences Radio 7 Vladivostok 690041 Russian Federation Norwegian Institute for Water Research Gaustadalléen 21 Oslo Norway Department of Biological Sciences University of Bergen Postboks 7803 Bergen 5020 Norway Pennsylvania State University The Behrend College 4701 College Dr Erie 16563 PA United States Atmosphere and Ocean Research Institute The University of Tokyo 5-1-5 Kashiwanoha Kashiwa 277-8564 Japan Faculty of Fisheries T/S Nagasaki-Maru Nagasaki University 1-14 Bunkyo machi Nagasaki city Nagasaki 852-8521 Japan Faculty of Fisheries Sciences Hokkaido University 3-1-1 Minato-cho Hokkaido Hakodate 041-8611 Japan Institute of Integrated Science and Technology Nagasaki University 1-14 Bunkyo machi Nagasaki city Nagasaki 852-8521 Japan Tokyo Uni

A total of 8218 pelagic microplastic samples from the world’s oceans were synthesized to create a dataset composed of raw, calibrated, processed, and gridded data which are made available to the public. The raw microplastic abundance data were obtained by different research projects using surface net tows or continuous seawater intake. Fibrous microplastics were removed from the calibrated dataset. Microplastic abundance which fluctuates due to vertical mixing under different oceanic conditions was standardized. An optimum interpolation method was used to create the gridded data;in total, there were 24.4 trillion pieces (8.2 × 10⁴ ~ 57.8 × 10⁴ tons) of microplastics in the world’s upper oceans. © The Author(s) 2021.

关键词： 2D maps in the world’s ocean Microplastic abundance Multilevel dataset

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Voltage gated inter-cation selective ion channels from graphene nanopores

arXiv

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arXiv 2019年

作者： Cantley, Lauren Swett, Jacob L. Lloyd, David Cullen, David A. Zhou, Ke Bedworth, Peter V. Heise, Scott Rondinone, Adam J. Xu, Zhiping Sinton, Steve Bunch, J. Scott Department of Mechanical Engineering Boston University BostonMA02215 United States Advanced Technology Center Lockheed Martin Space Palo AltoCA94304 United States Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak RidgeTN37831 United States Applied Mechanics Laboratory Department of Engineering Mechanics Center for Nano and Micro Mechanics Tsinghua University Beijing100084 China Division of Materials Science and Engineering Boston University BrooklineMA02446 United States

With the ability to selectively control ionic flux, biological protein ion channels perform a fundamental role in many physiological processes. For practical applications that require the functionality of a biological ion channel, graphene provides a promising solidstate alternative, due to its atomic thinness and mechanical strength. Here, we demonstrate that nanopores introduced into graphene membranes, as large as 50 nm in diameter, exhibit inter-cation selectivity with a ∼20x preference for K+over divalent cations and can be modulated by an applied gate voltage. Liquid atomic force microscopy of the graphene devices reveals surface nanobubbles near the pore to be responsible for the observed selective behavior. Molecular dynamics simulations indicate that translocation of ions across the pore likely occurs via a thin water layer at the edge of the pore and the nanobubble. Our results demonstrate a significant improvement in the inter-cation selectivity displayed by a solidstate nanopore device and by utilizing the pores in a de-wetted state, offers an approach to fabricating selective graphene membranes that does not rely on the fabrication of sub-nm pores. Copyright © 2019, The Authors. All rights reserved.

关键词： Graphene

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Current md forcefields fail to capture key features of protein structure and fluctuations: a case study of cyclophilin a and t4 lysozyme

arXiv

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arXiv 2020年

作者： Mei, Zhe Grigas, Alex T. Treado, John D. Corres, Gabriel Melendez Vuorte, Maisa Sammalkorpi, Maria Regan, Lynne Levine, Zachary A. O’Hern, Corey S. Department of Chemistry Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Department of Biology UPR Humacao Puerto RicoHumacao00792 Puerto Rico Department of Chemistry and Materials Science School of Chemical Engineering Aalto University Aalto Finland Department of Bioproducts and Biosystems School of Chemical Engineering Aalto University Aalto Finland Institute of Quantitative Biology Biochemistry and Biotechnology Center for Synthetic and Systems Biology School of Biological Sciences University of Edinburgh Edinburgh United Kingdom Department of Pathology Yale School of Medicine New HavenCT06520 United States Department of Molecular Biophysics and Biochemistry Yale University New HavenCT06520 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States

Globular proteins undergo thermal fluctuations in solution, while maintaining an overall well-defined folded structure. In particular, studies have shown that the core structure of globular proteins differs in small, but significant ways when they are solved by x-ray crystallography versus solution-based NMR spectroscopy. Given these discrepancies, it is unclear whether molecular dynamics (MD) simulations can accurately recapitulate protein conformations. We therefore perform extensive MD simulations across multiple force fields and sampling techniques to investigate the degree to which computer simulations can capture the ensemble of conformations observed in experiments. By analyzing fluctuations in the atomic coordinates and core packing, we show that conformations sampled in MD simulations both move away from and sample a larger conformational space than the ensemble of structures observed in NMR experiments. However, we find that adding inter-residue distance restraints that match those obtained via Nuclear Overhauser Effect measurements enables the MD simulations to sample more NMR-like conformations, though significant differences between the core packing features in restrained MD and the NMR ensemble remain. Given that the protein structures obtained from the MD simulations possess smaller and less dense protein cores compared to those solved by NMR, we suggest that future improvements to MD forcefields should aim to increase the packing of hydrophobic residues in protein cores. © 2020, CC BY.

关键词： Molecular dynamics

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Enhanced strength and ductility in a high-entropy alloy via ordered oxygen complexes (vol 563, pg 546, 2018)

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NATURE 2019年第7739期565卷 E8-E8页

作者： Lei, Zhifeng Liu, Xiongjun Wu, Yuan Wang, Hui Jiang, Suihe Wang, Shudao Hui, Xidong Wu, Yidong Gault, Baptiste Kontis, Paraskevas Raabe, Dierk Gu, Lin Zhang, Qinghua Chen, Houwen Wang, Hongtao Liu, Jiabin An, Ke Zeng, Qiaoshi Nieh, Tai-Gang Lu, Zhaoping Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing China Department of Microstructure Physics and Alloy Design Max-Planck-Institut für Eisenforschung Düsseldorf Germany Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China College of Materials Science and Engineering Chongqing University Chongqing China Institute of Applied Mechanics Zhejiang University Hangzhou China School of Materials Science and Engineering Zhejiang University Hangzhou China Spallation Neutron Source Oak Ridge National Laboratory Oak Ridge USA Center for High Pressure Science and Technology Advanced Research Pudong China Department of Materials Science and Engineering University of Tennessee Oak Ridge USA

Change history: In this Letter, owing to a production error, all the data points (except the two points for O-2 and N-2, respectively) were missing in Fig. 1b. The figure has been corrected online.

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Challenges with vitrification of Hanford High-Level Waste (HLW) to borosilicate glass – An overview

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Journal of Non-Crystalline Solids: X 2019年 4卷

作者： Goel, Ashutosh McCloy, John S. Pokorny, Richard Kruger, Albert A. Department of Materials Science and Engineering Rutgers The State University of New Jersey PiscatawayNJ United States School of Mechanical & Materials Engineering and Materials Science & Engineering Program Washington State University PullmanWA United States Laboratory of Inorganic Materials Joint Workplace of the University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czechia The Institute of Rock Structure and Mechanics of the ASCR v.v.i V Holešovičkách 41 Prague 8182 09 Czech Republic U.S. Department of Energy Office of River Protection RichlandWA United States

The Hanford site in Washington State houses ~56 million gallons of radioactive wastes stored in 177 underground tanks. The waste must be immobilized and permanently stored, and the plan is to separate the tank wastes into low activity waste (LAW) and high-level waste (HLW) streams. The U.S. department of Energy is building a Waste Treatment and Immobilization Plant at Hanford site to separately vitrify these two waste streams in borosilicate glass using Joule-heated ceramic melters (JHCM). Although the process of nuclear waste vitrification seems to be well established, in practicality, it is faced with complex problems starting from the design of glass compositions, to processing in melters and long-term performance of the final vitrified waste forms. The article presents an overview of our current understanding of critical challenges related to the development and performance of HLW glasses. © 2019

关键词： Radioactive wastes

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