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General framework for the mechanical response of metallic glasses during strain-rate-dependent uniaxial compression

Physical Review Materials 2023年第10期7卷 105604-105604页

作者： Weiwei Jin Amit Datye Udo D. Schwarz Mark D. Shattuck Corey S. O'Hern Department of Mechanical Engineering and Materials Science Yale University New Haven Connecticut 06520 USA Department of Chemical and Environmental Engineering Yale University New Haven Connecticut 06520 USA Benjamin Levich Institute and Physics Department The City College of New York New York New York 10031 USA Department of Physics Yale University New Haven Connecticut 06520 USA Department of Applied Physics Yale University New Haven Connecticut 06520 USA Graduate Program in Computational Biology and Bioinformatics Yale University New Haven Connecticut 06520 USA

Experimental data on compressive strength σmax versus strain rate ɛ̇eng for metallic glasses undergoing uniaxial compression show varying strain rate sensitivity. For some metallic glasses, σmax decreases with increasing ɛ̇eng, while for others, σmax increases with increasing ɛ̇eng, and for certain alloys σmax versus ɛ̇eng is nonmonotonic. To understand their strain rate sensitivity, we conduct molecular dynamics simulations of metallic glasses undergoing uniaxial compression at finite strain rates and coupled to heat baths with a range of temperatures T0 and damping parameters b. In the T0→0 and b→0 limits, we find that the compressive strength σmax versus temperature T obeys a “chevron-shaped” scaling relation. In the low-strain-rate regime, σmax decreases linearly with increasing T, whereas σmax grows as a power law with decreasing T in the high-strain-rate regime. For T0>0, σmax(T) deviates from the scaling curve at low strain rates, but σmax(T) rejoins the scaling curve as the strain rate increases. Enhanced dissipation reduces compression-induced heating, which causes σmax(T) to deviate from the b→0 scaling behavior for intermediate strain rates, but σmax(T) converges to the high-strain-rate power-law scaling behavior at sufficiently high strain rates. Determining σmax(T) as a function of b and T0 provides a general framework for explaining the strain rate sensitivity of metallic glasses under compression.

关键词： Compressive strength Mechanical deformation Amorphous materials Metallic glasses Molecular dynamics

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To Sharpen or not to Sharpen? On the Effect of Sharpening Filters Applied to Magnified Images 14

To Sharpen or not to Sharpen? On the Effect of Sharpening Fi...

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14th International Conference on Digital Image Processing, ICDIP 2022

作者： Emmendorfer, Leonardo R. de Olviveira, Vinicius Menezes Schein, Tatiana T. de Jesus, Junior C. Rodriguez, Bárbara D.A. Electrical Energy Processing Department Federal University of Santa Maria 97105-340 Brazil Center for Computational Science Federal University of Rio Grande 96201-900 Brazil Computational Modeling PhD Program Federal University of Rio Grande 96201-900 Brazil Computer Engineering Graduate Program Federal University of Rio Grande 96201-900 Brazil Institute of Mathematics Statistics and Physics Federal University of Rio Grande 96201-900 Brazil

ISBN: (纸本)9781510657564

Super-resolution algorithms aim to produce magnified high-resolution versions from low-resolution images. Some methods, however, are prone to generate blur during the process. Simple sharpening filters are adopted to alleviate this type of artifact. However, the actual effectiveness of this approach is not clear-cut in the literature. This work evaluates the effect of three simple sharpening filters on the quality of images obtained from super-resolution methods. Two metrics were considered in the evaluation: the Peak signal-to-noise ratio (PSNR) metric, and the Learned Perceptual Image Patch Similarity (LPIPS). One of the filters could consistently improve the LPIPS metric of magnified images from diverse benchmark sets on top of seven super-resolution methods. The increments obtained for the perceptual metric seem to occur due to the sharpening effect. Improvements on PSNR values were not as consistent. © 2022 SPIE.

关键词： Quality control

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1D GRPIC Simulations of Stellar-Mass Black Hole Magnetospheres: Semi-Analytic Model of Gamma-Rays from Gaps

arXiv

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arXiv 2023年

作者： Kin, Koki Kisaka, Shota Toma, Kenji Kimura, Shigeo S. Levinson, Amir Astronomical Institute Graduate School of Science Tohoku University Sendai980-8578 Japan Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan Frontier Research Institute for Interdisciplinary Sciences Tohoku University Sendai980-8578 Japan The Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel

In the absence of a sufficient amount of plasma injection into the black hole (BH) magnetosphere, the force-free state of the magnetosphere cannot be maintained, leading to the emergence of strong, time-dependent, longitudinal electric field (spark gap). Recent studies of supermassive BH magnetospheres by using analytical methods and particle-in-cell (PIC) simulations propose the possibility of the efficient particle acceleration and consequent gamma-ray emission in the spark gap. In this work, we perform one-dimensional general relativistic PIC simulations to examine the gamma-ray emission from stellar-mass BH magnetospheres. We find that intermittent spark gaps emerge and particles are efficiently accelerated, in a similar manner to the supermassive BH case. We build a semi-analytic model of the plasma dynamics and radiative processes which reproduces the maximum electron energies and peak gamma-ray luminosities in the simulation results. Based on this model, we show that gamma-ray signals from stellar-mass BHs wandering through the interstellar medium could be detected by gamma-ray telescopes such as the Fermi Large Area Telescope, or the Cherenkov Telescope Array. Copyright © 2023, The Authors. All rights reserved.

关键词： Magnetosphere

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Evanescent wave spectral singularities in non-Hermitian photonics

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Physical Review B 2024年第4期109卷 L041405-L041405页

作者： Huan He Zhaoxian Chen Huanan Li Cheng-Hou Tu Jingjun Xu Andrea Alù MOE Key Laboratory of Weak-Light Nonlinear Photonics School of Physics Nankai University Tianjin 300071 China College of Engineering and Applied Sciences Collaborative Innovation Center of Advanced Microstructures and National Laboratory of Solid State Microstructures Nanjing University Nanjing 210023 China Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA

Spectral singularities (SSs) emerge at isolated real frequencies when the scattering coefficients of a system diverge, producing scattering anomalies in non-Hermitian systems. Here, based on parity-time symmetry, we introduce SSs for evanescent waves, and explore their exotic features. We show that evanescent wave SSs can realize highly reconfigurable unidirectional lasers and absorbers, and offer the opportunity to observe extreme scattering anomalies associated with SSs in fully passive platforms, decoupling their extreme scattering responses from energy considerations. More broadly, our study opens avenues for non-Hermitian wave engineering, showcasing a link between non-Hermitian physics and structured waves, with implications in nano-optics for extreme wave-matter interactions and functional devices.

关键词： Evanescent waves Wave scattering Non-Hermitian systems

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B(s) → D((s∗))M decays in the presence of final-state interaction

arXiv

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arXiv 2024年

作者： Panuluh, Albertus Hariwangsa Tanaka, Satoshi Umeeda, Hiroyuki Physics Program Graduate School of Advanced Science and Engineering Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima739-8526 Japan Department of Physics Education Faculty of Teacher Training and Education Sanata Dharma University Paingan Maguwohardjo Sleman Yogyakarta55282 Indonesia Ibaraki prefecture Japan Center for Theoretical Physics College of Physics Jilin University Changchun130012 China China Center of Advanced Science and Technology Beijing100190 China Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China

In light of the recent data for B¯(s) → D((s∗))P and B¯(s) → D(s)V decays, we perform a model-independent phenomenological analysis in the presence of quasi-elastic rescattering. With the Wilson coefficients including contributions beyond the standard model, lifetimes of B meson as well as the Bd0 −B¯d0 mixing are investigated for clarifying correlations among the observables. We show that parameter regions for quasi-elastic rescattering, the size of color-suppressed tree amplitudes and new physics are constrained due to the lifetime data. As a consequence, it is revealed that this scenario can be testable by the future LHCb measurement of width difference in Bd0 − B¯d0 mixing and semi-leptonic CP asymmetry. © 2024, CC BY.

关键词： Bosons

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Biodegradable Pbat/Pla Blend Films Incorporated with Turmeric and Cinnamomum Powder: A Potential Alternative for Active Food Packaging

SSRN

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SSRN 2023年

作者： de Castro, Layara L.R.L. Abreu, Iago R. Braz, Cristiano J.F. Rodrigues, Samara C.S. dos Araújo, Regilda S.R.M. Folkersma, Rudy de Carvalho, Laura H. Barbosa, Renata Alves, Tatianny S. Graduate Program in Materials Science and Engineering Federal University of Piauí Teresina64.049-550 Brazil Department of Physics Federal Institute of Education Science and Technology of Piauí Teresina Central Campus Teresina64.000-040 Brazil Department of Nutrition Federal University of Piauí Teresina64.049-550 Brazil NHL Stenden University of Applied Sciences Groningen9727 Netherlands Graduate Program in Materials Science and Engineering Federal University of Campina Grande PI TeresinaCEP: 58.100-000 Brazil

Active packaging made from biodegradable polymers and natural additives appears as an ecological alternative. In addition to having antioxidant activity and enhancing food preservation, it allows mitigating the negative impacts caused by improper disposal. This study pursued to produce biodegradable films based on a polymer blend PBAT/PLA (Ecovio®) using the flat extrusion method. The films were prepared with the incorporation of 5 wt% of powdered turmeric or cinnamon as natural additives. The films obtained, and those reprocessed twice, were characterized in terms of colorimetric, UV light transmittance, water contact angle, water vapor permeability, morphology, mechanical properties, and antioxidant activity. Cinnamon reduced the UV light transmittance and made a surface more hydrophobic. Reprocessing led to greater elongation and maximum load, associated with increased dispersion and distribution, as evidenced in the morphological analysis. The films developed have significant potential for applications in active food packaging, with emphasis on cinnamon-additivated films. © 2023, The Authors. All rights reserved.

关键词： Biodegradable polymers

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Giant long-range dipole-dipole interactions in a plasmonic lattice

Giant long-range dipole-dipole interactions in a plasmonic l...

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Frontiers in Optics + Laser Science 2021, FiO+LS 2021 - Part of Frontiers in Optics, FiO 2021

作者： Boddeti, Ashwin K. Guan, Jun Sentz, Tyler Juarez, Xitali Newman, Ward Cortes, Cristian Odom, Teri W. Jacob, Zubin School of Electrical and Computer Engineering Birck Nanotechnology Center Purdue University West LafayetteIN47907 United States Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Intel Corporation BeavertonOR97007 United States Center for Nanoscale Materials Argonne National Laboratory LemontIL60439 United States Graduate Program in Applied Physics Department of Materials Science and Engineering Department of Chemistry Northwestern University EvanstonIL60208 United States

We observe long-range dipole-dipole interactions in a plasmonic lattice. Fluorescence lifetime measurements show density-dependent non-exponential decay dynamics over 800nm mean nearest-neighbour separation distances ... 详细信息

ISBN: (纸本)9781557528209

关键词： Plasmonics

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Surface Second Harmonic Generation from Topological Dirac Semimetal PdTe2

arXiv

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arXiv 2023年

作者： Faizanuddin, Syed Mohammed Chien, Ching-Hang Chan, Yao-Jui Kuo, Chia-Nung Lue, Chin Shuan Wen, Yu-Chieh Institute of Physics Academia Sinica Taipei11529 Taiwan Nano Science and Technology Program Taiwan International Graduate Program Academia Sinica Taipei11529 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu300044 Taiwan Department of Physics National Cheng Kung University Tainan701401 Taiwan Research Center for Applied Sciences Academia Sinica Taipei11529 Taiwan

Three-dimensional topological semimetals were shown to host anomalously strong optical nonlinearity, but yet whether such enhancement can occur at their surfaces via topological boundary states remains an open question. Here we tackle this question by examining polarization-dependent rotational-anisotropy optical second harmonic generation (SHG) from transition metal dichalcogenide Dirac semimetal PdTe2. We find its reflected SHG to follow C3v surface symmetry with a time-varying intensity dictated by oxidation kinetics of the material after its surface cleavage, confirming the surface-derived origin of SHG. The complex surface nonlinear optical susceptibility tensor is fully characterized by heterodyne interferometry, unveiling a hidden giant out-of-plane response χzzz (2) (> 10.6 nm2/V or, equivalently, an effective bulk nonlinear susceptibility > 10.3 nm/V). Our results highlight the topological surfaces/interfaces as a new route toward nonlinear optical applications with released symmetry constraints, and demonstrate SHG as a viable means for in situ probing of surface chemistry of topological systems. Copyright © 2023, The Authors. All rights reserved.

关键词： Nonlinear optics

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Controllable Transmission Switch Based on Asymmetric Coupled Nonlinear Resonances

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Physical Review Applied 2023年第6期19卷 064002-064002页

作者： Hady Moussa Michele Cotrufo Andrea Alù Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Department of Electrical Engineering City College of City University of New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA

We explore the design and implementation of a passive reconfigurable switch based on nonlinear Fano resonators asymmetrically coupled to two ports. It was recently shown that asymmetric nonlinear resonators could provide passive bias-free nonreciprocal transmission when they were excited only from one port at a time. Here, we show that, by suitably exploiting time-reversal symmetry, this class of devices can also lead to controllable transmission routing, whereby a low-power pulse injected from one port controls the transmission of a larger power signal injected from the opposite port. This effect can be used to realize a power- and/or phase-controlled transmission switch with minimal power consumption. We first analyze the device with a circuit model to gain physical insights into its operation and to establish optimal operation conditions. We then provide a proof-of-principle experimental demonstration, reporting a device whereby the transmission of a 20-dBm signal can be switched from about 10% to 40% by controlling either the power or phase of a signal about 10 times weaker. This work demonstrates an alternative way to develop low-energy power-controlled reconfigurable switches for applications ranging from radar technology to wireless communications.

关键词： Metamaterials Nonlinear waveguides Optoelectronics Radio frequency techniques Devices

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Nernst-Ettingshausen effect in thin Pt and W films at low temperatures

arXiv

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arXiv 2023年

作者： Luo, Renjie Legvold, Tanner J. Chen, Liyang Natelson, Douglas Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

As spin caloritronic measurements become increasingly common techniques for characterizing material properties, it is important to quantify potentially confounding effects. We report measurements of the Nernst-Ettingshausen response from room temperature to 5 K in thin film wires of Pt and W, metals commonly used as inverse spin Hall detectors in spin Seebeck characterization. Johnson-Nyquist noise thermometry is used to assess the temperature change of the metals with heater power at low temperatures, and the thermal path is analyzed via finite-element modeling. The Nernst-Ettingshausen response of W is found to be approximately temperature-independent, while the response of Pt increases at low temperatures. These results are discussed in the context of theoretical expectations and the possible role of magnetic impurities in Pt. Copyright © 2023, The Authors. All rights reserved.

关键词： Inverse problems

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