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arXiv 2023年

作者： Nawano, Aya Schroers, Jan Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

Metallic glasses are frequently used as structural materials. Therefore, it is important to develop methods to predict their mechanical response as a function of the microstructure prior to loading. We develop a novel coarse-grained spring network model, which describes the mechanical response of metallic glasses using an equivalent series network of springs, which can break and re-form to mimic atomic rearrangements during deformation. To validate the spring network model, we perform numerical simulations of quasistatic, uniaxial tensile deformation of Lennard-Jones and embedded atom method (EAM) potentials for Cu50Zr50 metallic glasses in the absence of large-scale shear band formation. We consider samples prepared using a wide range of cooling rates and with different amounts of crystalline order. We show that both the Lennard-Jones and EAM models possess qualitatively similar stress σ versus strain γ curves. By specifying five parameters in the spring network model (ultimate strength, strain at ultimate strength, slopes of σ(γ) at γ = 0 and at large strain, and strain at fracture where σ = 0), we can accurately describe the form of the stress-strain curves during uniaxial tension for the computational studies of Cu50Zr50, as well as recent experimental studies of several Zr-based metallic glasses. For the computational studies of Cu50Zr50, we find that the yield strain distribution is shifted to larger strains for slowly cooled glasses compared to rapidly cooled glasses. In addition, the average number of new springs and their rate of formation decreases with decreasing cooling rate. These effects offset each other at large strains, causing the stress-strain curve to become independent of the sample preparation protocol in this regime. In future studies, we will extract the parameters that define the spring network model directly from atomic rearrangements that occur during uniaxial deformation. © 2023, CC BY-NC-ND.

关键词： Metallic glass

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Liquid crystal torons in Poiseuille-like flows

arXiv

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arXiv 2024年

作者： Amaral, Guilherme N.C. Zhao, Hanqing Sedahmed, Mahmoud Campante, Tomás Smalyukh, Ivan I. Tasinkevych, Mykola Telo da Gama, Margarida M. Coelho, Rodrigo C.V. Centro de Física Teórica e Computacional Faculdade de Ciências Universidade de Lisboa Lisboa1749-016 Portugal Departamento de Física Faculdade de Ciências Universidade de Lisboa LisboaP-1749-016 Portugal Department of Physics Soft Materials Research Center University of Colorado BoulderCO80309 United States Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima739-8511 Japan SOFT Group School of Science and Technology Nottingham Trent University Clifton Lane NottinghamNG11 8NS United Kingdom

Three-dimensional (3D) simulations of the structure of liquid crystal (LC) torons, topologically protected distortions of the LC director field, under material flows are rare but essential in microfluidic applications. Here, we show that torons adopt a steady-state configuration at low flow velocity before disintegrating at higher velocities, in line with experimental results. Furthermore, we show that under partial slip conditions at the boundaries, the flow induces a reversible elongation of the torons, also consistent with the experimental observations. These results are in contrast with previous simulation results for 2D skyrmions under similar flow conditions, highlighting the need for a 3D description of this LC soliton in relation to its coupling to the material flow. These findings pave the way for future studies of other topological solitons, like hopfions and heliknotons, in flowing soft matter systems. Copyright © 2024, The Authors. All rights reserved.

关键词： Crystal structure

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H2S Sensors: Fumarate‐Based fcu‐MOF Thin Film Grown on a Capacitive Interdigitated Electrode

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Angewandte Chemie 2016年第51期128卷

作者： Omar Yassine Osama Shekhah Ayalew H. Assen Youssef Belmabkhout Khaled N. Salama Mohamed Eddaoudi Sensors Lab Electrical Engineering Program Division of Computer Electrical and Mathematical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia Functional Materials Design Discovery and Development research group (FMD3) Advanced Membranes & Porous Materials Center Division of Physical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia

Herein we report the fabrication of an advanced sensor for the detection of hydrogen sulfide (H 2 S) at room temperature, using thin films of rare‐earth metal (RE)‐based metal–organic framework (MOF) with underlying fcu topology. This unique MOF‐based sensor is made via the in situ growth of fumarate‐based fcu ‐MOF (fum‐ fcu ‐MOF) thin film on a capacitive interdigitated electrode. The sensor showed a remarkable detection sensitivity for H 2 S at concentrations down to 100 ppb, with the lower detection limit around 5 ppb. The fum‐ fcu ‐MOF sensor exhibits a highly desirable detection selectivity towards H 2 S vs. CH 4 , NO 2 , H 2 , and C 7 H 8 as well as an outstanding H 2 S sensing stability as compared to other reported MOFs.

关键词： H2S Interdigital-Elektroden Metall-organische Gerüstverbindungen Seltenerdmetalle Sensoren

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Spongy Graphene as a Highly Efficient and Recyclable Sorbent for Oils and Organic Solvents

Spongy Graphene as a Highly Efficient and Recyclable Sorbent...

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The 4th International Conference of Recent Progress in Graphene Research 第四届石墨烯研究最新进展国际会议

作者： Hengchang BI Rodney S. Ruoff Xiao XIE Kuibo YIN Yilong ZHOU Shu WAN Longbing HE Feng XU Florian Banhart Litao SUN SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of EducationSoutheast UniversityNanjing210096P. R. China Department of Mechanical Engineering and Materials and Science ProgramThe University of Texas at AustinOne University Station C2200AustinTX 78712USA Institut de Physique et Chimie des MatériauxUMR 7504 CNRSUniversité de Strasbourg23 rue du Loess67034 StrasbourgFrance

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Reducing Anisotropy of Rhombohedral Bi-Rich Phase for High-Performance Ag-Alloyed Sn-Bi Low-Temperature Solders

SSRN

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SSRN 2023年

作者： Yang, Chih-Han Liu, Yu-Chen Nishikawa, Hiroshi Lin, Shih-Kang Department of Materials Science and Engineering National Cheng Kung University Tainan70101 Taiwan Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki Osaka567-0047 Japan Research Center National Cheng Kung University Tainan70101 Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan Core Facility Center National Cheng Kung University Tainan70101 Taiwan

The rhombohedral structure is with anisotropic properties, leading to brittle mechanical properties. However, it is one of the major constituent phases, the (Bi) phase, in the Sn-Bi-based low-temperature solders, which is demanding in the electronic industry for reducing the soldering temperature and alleviating the warpage in high-density fine-pitch electronic packaging. Herein, we proposed a high-performance Ag-alloyed Sn-Bi (SBA) low-temperature solder by reducing the fraction and, more importantly, the anisotropy of the (Bi) phase. We found that the (Bi) phase exhibited considerable solubility for Ag and Sn, even after thermal aging, without any nanoprecipitates as confirmed with both CALPHAD-type thermodynamic modeling and high-resolution TEM. The solution effects of Ag and Sn in the (Bi) phase is elaborated based on in situ nano-indentation, EPMA compositional analyses, EBSD characterizations, and ab initio calculations. The presence of Ag and Sn in the (Bi) phases resulted in both solid solution hardening and softening effects, depending on the Schmid factor of the grain. As a result, in (Bi) polycrystals, alloying could effectively mitigate the anisotropic mechanical properties of the (Bi) phase and facilitated a more uniform dispersion of forces exerted among (Bi) grains in all orientations. Consequently, the designed SBA solder exhibited superior mechanical properties, e.g., an ultimate tensile strength (UTS) of 55 MPa, elongation of 46%, and toughness of 20.6 x 106 J/m3 at a strain rate of 0.0005 s-1. This understanding opens the door for enhanced rhombohedral phase in alloy design for various applications. © 2023, The Authors. All rights reserved.

关键词： Anisotropy

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Spatially separated self-assembled silver dendrites for highly sensitive SERS applications

arXiv

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arXiv 2018年

作者： Yakimchuk, D.V. Kaniukov, E.Y. Lepeshov, S.I. Bundyukova, V.D. Demyanov, S.E. Arzumanyan, G.M. Doroshkevich, N.V. Mamatkulov, K.Z. Alù, A. Bochmann, A. Presselt, M. Stranik, O. Krasnok, A. Sivakov, V. Scientific-Practical Materials Research Center NAS of Belarus Minsk ITMO University St. Petersburg Russian Federation Joint Institute for Nuclear Research Dubna Russian Federation Dubna State University Dubna Russian Federation Photonics Initiative Advanced Science Research Center Physics Program Graduate Center City University of New York Department of Electrical Engineering City College of New York United States Ernst-Abbe-Hochschule Jena Jena Germany Leibniz Institute of Photonic Technology Jena Germany

Even after more than four decades of rapid-pace advances, the adoption of Surface-Enhanced Raman Scattering (SERS) remains limited, due to the difficulties in fabrication of effective and affordable nanostructured surfaces or templates. From this point-of-view, self-assembly techniques of SERS substrates formation allowing fabrication of highly branched dendritic silver nanostructures, which are very promising for biosensor applications. However, these techniques suffer from the lack of control over the resulting structures. Herein, we propose an electroless wetchemical approach for highly reproducible fabrication of spatially separated plasmonic active silver dendrites in a porous matrix of Si/SiO2 template via controlled self-assembly of silver in a limited volume. The proposed approach allows fabrication of spatially separated silver dendrites with sub-10-nm gaps between neighboring branches, which possessing strong electric field enhancement ina wide spectral range. The fabricated silver dendritic structures enable a SERS enhancement factor of ∼108and the analyte detection limit of ∼10-15M, which is at the level of single molecule sensitivity. The comparison of simulation results with SERS experiments allows to distinguish the presence of electromagnetic and chemical contributions, which have a different effect at various analyte concentrations. Copyright © 2018, The Authors. All rights reserved.

关键词： Fabrication

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Search for the magnetic monopole at a magnetoelectric surface

arXiv

引用

arXiv 2018年

作者： Meier, Q.N. Fechner, M. Nozaki, T. Sahashi, M. Salman, Z. Prokscha, T. Suter, A. Schoenherr, P. Lilienblum, M. Borisov, P. Dzyaloshinskii, I.E. Fiebig, M. Luetkens, H. Spaldin, N.A. Department of Materials ETH Zurich ZürichCH-8093 Switzerland Max Planck Institute for the Structure and Dynamics of Matter Hamburg22761 Germany Department of Electronic Engineering Tohoku University Sendai980-8579 Japan ImPACT Program Japan Science and Technology Agency Tokyo102-0076 Japan Laboratory for Muon Spin Spectroscopy Paul Scherrer Institute Villigen PSICH-5232 Switzerland Department of Physics School of Science Loughborough University LoughboroughLE11 3TU United Kingdom School of Physical Sciences University of California Irvine IrvineCA92697 United States

We show, by solving Maxwell's equations, that an electric charge on the surface of a slab of a linear magnetoelectric material generates an image magnetic monopole below the surface provided that the magnetoelectric has a diagonal component in its magnetoelectric response. The image monopole, in turn, generates an ideal monopolar magnetic field outside of the slab. Using realistic values of the electric- and magnetic- field susceptibilities, we calculate the magnitude of the effect for the prototypical magnetoelectric material Cr2O3. We use low energy muon spin rotation to measure the strength of the magnetic field generated by charged muons as a function of their distance from the surface of a Cr2O3 film, and show that the results are consistent with the existence of the monopole. We discuss other possible routes to detecting the monopolar field, and show that, while the predicted monopolar field generated by Cr2O3 is above the detection limit for standard magnetic force microscopy, detection of the field using this technique is prevented by surface charging effects. Copyright © 2018, The Authors. All rights reserved.

关键词： Chromium compounds

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Emulating Complex Synapses Using Interlinked Proton Conductors

arXiv

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arXiv 2024年

作者： Zhang, Lifu Li, Ji-An Hu, Yang Jiang, Jie Lai, Rongjie Benna, Marcus K. Shi, Jian Department of Materials Science and Engineering Rensselaer Polytechnic Institute TroyNY12180 United States Neurosciences Graduate Program University of California San Diego La Jolla CA92093 United States Department of Mathematics Purdue University West LafayetteIN47907 United States Department of Neurobiology School of Biological Sciences University of California at San Diego La Jolla CA92093 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute TroyNY12180 United States

In terms of energy efficiency and computational speed, neuromorphic electronics based on non-volatile memory devices is expected to be one of most promising hardware candidates for future artificial intelligence (AI). However, catastrophic forgetting, networks rapidly overwriting previously learned weights when learning new tasks, remains as a pivotal hurdle in either digital or analog AI chips for unleashing the true power of brain-like computing. To address catastrophic forgetting in the context of online memory storage, a complex synapse model (the Benna-Fusi model) has been proposed recently[1], whose synaptic weight and internal variables evolve following a diffusion dynamics. In this work, by designing a proton transistor with a series of charge-diffusion-controlled storage components, we have experimentally realized the Benna-Fusi artificial complex synapse. The memory consolidation from coupled storage components is revealed by both numerical simulations and experimental observations. Different memory timescales for the complex synapse are engineered by the diffusion length of charge carriers, the capacity and number of coupled storage components. The advantage of the demonstrated complex synapse in both memory capacity and memory consolidation is revealed by neural network simulations of face familiarity detection. Our experimental realization of the complex synapse suggests a promising approach to enhance memory capacity and to enable continual learning. Copyright © 2024, The Authors. All rights reserved.

关键词： Computational efficiency

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Effect of disorder on the metal-insulator transition of vanadium oxides: Local versus global effects

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Physical Review B 2015年第20期91卷 205123-205123页

作者： Juan Gabriel Ramirez Thomas Saerbeck Siming Wang J. Trastoy M. Malnou J. Lesueur Jean-Paul Crocombette Javier E. Villegas Ivan K. Schuller Department of Physics and Center for Advanced Nanoscience University of California San Diego La Jolla California 92093 USA Materials Science and Engineering Program University of California San Diego La Jolla California 92093 USA Unité Mixte de Physique CNRS/Thales 1 avenue A Fresnel 91767 Palaiseau France Université Paris Sud 11 91405 Orsay France LPEM CNRS-ESPCI 10 rue Vauquelin 75231 Paris France CEA DEN Service de Recherches de Métallurgie Physique F-91191 Gif-sur-Yvette France

In this paper we investigate the effect of disorder on highly correlated electron systems, which exhibit metal-insulator transition (MIT) and structural-phase transition (SPT). We show that the effect of ion irradiation is strikingly different between V2O3 and VO2, two otherwise similar materials. Upon irradiation, the MIT and SPT temperatures in V2O3 decrease drastically at low absolute dosages, much lower than for VO2. At a low threshold dose, the insulating state of V2O3 drastically collapses into a metallic state. Contrary to this, irradiation of VO2 leads to a much milder reduction of the MIT and SPT temperatures and to a weak, gradual decrease of the insulating state resistivity—not suppressed even at one order of magnitude higher doses than the V2O3 threshold. These major differences imply that the phase transition in V2O3 arises from global (rather than local as in VO2) physical mechanisms that are extremely sensitive to disorder. This shows that the MIT and SPT may have substantially different physical origins in different systems, with the consequent major implications for theoretical descriptions of the MIT in highly correlated electron systems.

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Cover Feature: Mechanical Bond Induced Enhancement and Purification of Pyrene Emission in the Solid State (Chem. Eur. J. 42/2024)

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Chemistry – A European Journal 2024年第42期30卷

作者： Shu Zhang Ru Zhou Ningjin Zhang Yi An Zhiyang Liu Xu-Man Chen Quan Li Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing 211189 China Instrumental Analytical Centre Shanghai Jiao Tong University Shanghai 201100 China Materials Science Graduate Program Kent State University Kent OH 44242 USA

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