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International Conference on Advances in Material science, ICAMS 2020

作者： Kumar, Pawan Hodgson, Peter Beladi, Hossein Chowdhury, Amit Roy Makhatha, M.E. Dutt, A.K. University of Johannesburg Faculty of Engineering and the Built Environment Department of Engineering Metallurgy John Orr Building DFC 25 Louisa St Doornfontein Johannesburg2028 South Africa Institute For Frontier Materials Deakin University AustraliaVIC3216 Australia Aerospace Engineering and Applied Mechanics Department Indian Institute of Engineering Science and Technology Shibpur India Netaji Subhash Institute of Technology Bihta Amhara801118 India

ISBN: (纸本)9783035738353

Uni-axial compression (UAC) tests and further post deformation annealing (PDA) were done for 23Cr-6Ni-3Mo duplex stainless steel (DSS). The initial morphology was equiaxed (EQ) in nature. In the first stage of PDA, austenite showed limited static recrystallization (SRX) followed by static recovery (SRV);however ferrite showed static recovery (SRV). In the second stage of PDA, the austenite showed grain coarsening followed by disintegration of substructures (DIS);and ferrite revealed mostly SRV leading to grain coarsening. The third stage of PDA envisages substructural disintegration of unstable substructure leading to saturation in both austenite and ferrite. The substructural characteristics were provided by Electron backscattered diffraction (EBSD) and its post processing were done by using HKL Channel 5 software. © 2021 Trans Tech Publications Ltd, Switzerland.

关键词： Restoration

Vanadium-Doped Molybdenum Disulfide Monolayers with Tunable Electronic and Magnetic Properties: Do Vanadium-Vacancy Pairs Matter?

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arXiv 2024年

作者： Zhou, Da Pham, Yen Thi Hai Dang, Diem Thi-Xuan Sanchez, David Oberoi, Aaryan Wang, Ke Fest, Andres Sredenschek, Alexander Liu, Mingzu Terrones, Humberto Das, Saptarshi Le, Dai-Nam Woods, Lilia M. Phan, Manh-Huong Terrones, Mauricio Department of Physics The Pennsylvania State University University ParkPA16802 United States Center for 2- Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States Department of Physics University of South Florida TampaFL33620 United States Department of Materials Science and Engineering The Pennsylvania State University University ParkPA16802 United States Department of Engineering Science and Mechanics The Pennsylvania State University University ParkPA16802 United States Materials Research Institute The Pennsylvania State University University ParkPA16802 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute TroyNY12180 United States Department of Chemistry The Pennsylvania State University University ParkPA16802 United States

Monolayers of molybdenum disulfide (MoS2) are the most studied two-dimensional (2D) transition-metal dichalcogenides (TMDs), due to its exceptional optical, electronic, and optoelectronic properties. Recent studies have shown the possibility of incorporating a small amount of magnetic transition metals (e.g., Fe, Co, Mn, V) into MoS2 to form a 2D dilute magnetic semiconductor (2D-DMS). However, the origin of the observed ferromagnetism has remained elusive, due to the presence of randomly generated sulfur vacancies during synthesis that can pair with magnetic dopants to form complex dopant-vacancy configurations altering the magnetic order induced by the dopants. By combining high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging with first-principles density functional theory (DFT) calculations and magnetometry data, we demonstrate the critical effects of sulfur vacancies and their pairings with vanadium atoms on the magnetic ordering in V-doped MoS2 (V-MoS2) monolayers. Additionally, we fabricated a series of field effect transistors on these V-MoS2 monolayers and observed the emergence of p-type behavior as the vanadium concentration increased. Our study sheds light on the origin of ferromagnetism in V-MoS2 monolayers and provides a foundation for future research on defect engineering to tune the electronic and magnetic properties of atomically thin TMD-based DMSs. © 2024, CC BY.

关键词： Monolayers

Autonomous Electron Tomography Reconstruction with Machine Learning

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arXiv 2023年

作者： Millsaps, William Schwartz, Jonathan Di, Zichao Wendy Jiang, Yi Hovden, Robert Department of Nuclear Engineering & Radiological Sciences University of Michigan Ann ArborMI United States Department of Materials Science and Engineering University of Michigan Ann ArborMI United States Mathematics and Computer Science Division Argonne National Laboratory LemontIL United States Advanced Photon Source Facility Argonne National Laboratory LemontIL United States Applied Physics Program University of Michigan Ann ArborMI United States

This manuscript is published in Microscopy and Microanalysis (DOI: 10.1093/micmic/ozad083). Modern electron tomography has progressed to higher resolution at lower doses by leveraging compressed sensing methods that minimize total variation (TV). However, these sparsity-emphasized reconstruction algorithms introduce tunable parameters that greatly influence the reconstruction quality. Here, Pareto front analysis shows that high-quality tomograms are reproducibly achieved when TV minimization is heavily weighted. However, in excess, compressed sensing tomography creates overly smoothed 3D reconstructions. Adding momentum to the gradient descent during reconstruction reduces the risk of over-smoothing and better ensures that compressed sensing is well behaved. For simulated data, the tedious process of tomography parameter selection is efficiently solved using Bayesian optimization with Gaussian processes. In combination, Bayesian optimization with momentum-based compressed sensing greatly reduces the required compute time-an 80% reduction was observed for the 3D reconstruction of SrTiO3 nanocubes. Automated parameter selection is necessary for large scale tomographic simulations that enable the 3D characterization of a wider range of inorganic and biological materials. © 2023, CC BY.

关键词： Compressed sensing

X-ray tomography based finite element modelling of non-crIMP fabric based fibre composite 18

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X-ray tomography based finite element modelling of non-crIMP...

18th European Conference on Composite materials, ECCM 2018

作者： Jespersen, Kristine M. Asp, Leif E. Hosoi, Atsushi Kawada, Hiroyuki Mikkelsen, Lars P. Department of Wind Energy Section of Composites and Materials Mechanics Technical University of Denmark Risø Campus Roskilde Denmark Department of Applied Mechanics and Aerospace Engineering Waseda University Tokyo Japan Kanagawa Japan Industrial and Materials Science Department Chalmers University of Technology Gothenburg Sweden

ISBN: (纸本)9781510896932

The current study presents a workflow to import a fibre bundle structure of a non-crimp fabric based fibre composite obtained by X-ray CT to a solvable 3D model in the finite element software ABAQUS. The considered fibre composite is similar to that used for the load carrying parts of wind turbine blades, and each layer of the non-crimp fabric contains fibre bundles oriented in the 0◦, 90◦, and ±45◦ directions. The 3D fibre bundle geometry is first segmented in the software AVIZO and then imported to Geomagic Wrap where the geometry is smoothened and converted into a nurbs surface that can be imported into ABAQUS. The resulting stress distribution is qualitatively compared to previous experimental observations and discussed. © CCM 2020 - 18th European Conference on Composite materials. All rights reserved.

关键词： Finite element method

BEAST DB: Grand-Canonical Database of Electrocatalyst Properties

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arXiv 2024年

作者： Tezak, Cooper Clary, Jacob Gerits, Sophie Quinton, Joshua Rich, Benjamin Singstock, Nicholas Alherz, Abdulaziz Aubry, Taylor Clark, Struan Hurst, Rachel Ben, Mauro Del Sutton, Christopher Sundararaman, Ravishankar Musgrave, Charles Vigil-Fowler, Derek Department of Chemical and Biological Engineering University of Colorado Boulder BoulderCO80309 United States Materials Chemical and Computational Science Directorate National Renewable Energy Laboratory GoldenCO80401 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute TroyNY12180 United States Department of Chemistry University of Colorado Boulder BoulderCO80309 United States Department of Mechanical Engineering University of Colorado Boulder BoulderCO80309 United States Department of Chemical Engineering College of Engineering and Petroleum Kuwait University Safat13060 Kuwait Applied Mathematics & Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Chemistry and Biochemistry University of South Carolina ColumbiaSC29208 United States Department of Materials Science and Engineering Rensselaer Polytechnic Institute TroyNY12180 United States Materials Science and Engineering Program University of Colorado Boulder BoulderCO80309 United States Renewable and Sustainable Energy Institute University of Colorado Boulder BoulderCO80309 United States Department of Chemical Engineering University of Utah Salt Lake CityUT84112 United States

We present BEAST DB, an open-source database comprised of ab initio electrochemical data computed using grand-canonical density functional theory in implicit solvent at consistent calculation parameters. The database contains over 20,000 surface calculations and covers a broad set of heterogenous catalyst materials and electrochemical reactions. Calculations were performed at self-consistent fixed potential as well as constant charge to facilitate comparisons to the computational hydrogen electrode. This article presents common use cases of the database to rationalize trends in catalyst activity, screen catalyst material spaces, understand elementary mechanistic steps, analyze electronic structure, and train machine learning models to predict higher fidelity properties. Users can interact graphically with the database by querying for individual calculations to gain granular understanding of reaction steps or by querying for an entire reaction pathway on a given material using an interactive reaction pathway tool. BEAST DB will be periodically updated, with planned future updates to include advanced electronic structure data, surface speciation studies, and greater reaction coverage. Copyright © 2024, The Authors. All rights reserved.

关键词： Database systems

Molecular dynamics simulations of heat transport using machine-learned potentials: A mini review and tutorial on GPUMD with neuroevolution potentials

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arXiv 2024年

作者： Dong, Haikuan Shi, Yongbo Ying, Penghua Xu, Ke Liang, Ting Wang, Yanzhou Zeng, Zezhu Wu, Xin Zhou, Wenjiang Xiong, Shiyun Chen, Shunda Fan, Zheyong College of Physical Science and Technology Bohai University Jinzhou China Department of Physical Chemistry School of Chemistry Tel Aviv University Tel Aviv6997801 Israel Department of Electronic Engineering and Materials Science and Technology Research Center The Chinese University of Hong Kong N.T. Shatin999077 Hong Kong MSP group QTF Centre of Excellence Department of Applied Physics Aalto University Aalto EspooFI-00076 Finland The Institute of Science and Technology Austria Am Campus 1 Klosterneuburg3400 Austria Department of Engineering Mechanics School of Civil Engineering and Transportation South China University of Technology Guangdong Province Guangzhou510640 China Department of Energy and Resources Engineering Peking University Beijing100871 China School of Advanced Engineering Great Bay University Dongguan523000 China Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices School of Materials and Energy Guangdong University of Technology Guangzhou510006 China Department of Civil and Environmental Engineering George Washington University WashingtonDC20052 United States

Molecular dynamics (MD) simulations play an important role in understanding and engineering heat transport properties of complex materials. An essential requirement for reliably predicting heat transport properties is the use of accurate and efficient interatomic potentials. Recently, machine-learned potentials (MLPs) have shown great promise in providing the required accuracy for a broad range of materials. In this mini review and tutorial, we delve into the fundamentals of heat transport, explore pertinent MD simulation methods, and survey the applications of MLPs in MD simulations of heat transport. Furthermore, we provide a step-by-step tutorial on developing MLPs for highly efficient and predictive heat transport simulations, utilizing the neuroevolution potentials (NEPs) as implemented in the GPUMD package. Our aim with this mini review and tutorial is to empower researchers with valuable insights into cutting-edge methodologies that can significantly enhance the accuracy and efficiency of MD simulations for heat transport studies. Copyright © 2024, The Authors. All rights reserved.

关键词： Molecular dynamics

Subdiffusive wave transport and weak localization transition in three-dimensional stealthy hyperuniform disordered systems

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Physical Review B 2022年第6期105卷 064204-064204页

作者： F. Sgrignuoli S. Torquato L. Dal Negro Department of Electrical and Computer Engineering & Photonics Center Boston University 8 Saint Mary's Street Boston Massachusetts 02215 USA Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08540 USA Division of Material Science and Engineering Boston University 15 Saint Mary's Street Brookline Massachusetts 02446 USA Department of Physics Boston University 590 Commonwealth Avenue Boston Massachusetts 02215 USA

The purpose of this work is to understand the fundamental connection between structural correlations and light localization in three-dimensional (3D) open scattering systems of finite size. We numerically investigate the transport of vector electromagnetic waves scattered by resonant electric dipoles spatially arranged in 3D space by stealthy hyperuniform disordered point patterns. Three-dimensional stealthy hyperuniform disordered systems are engineered with different structural correlation properties determined by their degree of stealthiness χ. Such fine control of exotic states of amorphous matter enables the systematic design of optical media that interpolate in a tunable fashion between uncorrelated random structures and crystalline materials. By solving the electromagnetic multiple scattering problem using Green's matrix spectral method, we establish a transport phase diagram that demonstrates a distinctive transition from a diffusive to a weak localization regime beyond a critical scattering density that depends on χ. The transition is characterized by studying the Thouless number and the spectral statistics of the scattering resonances. In particular, by tuning the χ parameter, we demonstrate large spectral gaps and suppressed subradiant proximity resonances, facilitating light localization. Moreover, consistently with previous studies, our results show a region of the transport phase diagram where the investigated scattering systems become transparent. Our work provides a systematic description of the transport and weak localization properties of light in stealthy hyperuniform structures and motivates the engineering of photonic systems with enhanced light-matter interactions for applications to both classical and quantum devices.

关键词： Anderson localization Light-matter interaction Mesoscopics Photonics Scattering theory Weak localization Metamaterials

Stretch-based kirigami structure with folding lines for stretchable electronics

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npj Flexible Electronics 2025年第1期9卷 1-8页

作者： Nakamura, Nagi Iwase, Eiji Department of Applied Mechanics and Aerospace Engineering Waseda University Tokyo Japan Kagami Memorial Research Institute for Materials Science and Technology Waseda University Tokyo Japan

We propose a stretch-based kirigami structure with folding lines (referred to as a “kiri-origami” structure) and folding methods of the kiri-origami structure for stretchable electronic devices. The kiri-origami structures have the advantages that rigid electronic elements such as surface mount devices (SMDs) can be mounted and large-number-of-unit structures can be folded up. We achieved the folding-up of the kiri-origami structure using buffer structures and biaxial extension to remove the cause of distortion and effectively utilized tensile force for folding. Undesirable deformations, such as panel warpage and hinge torsion, could not be ignored when using materials and configurations as stretchable electronic substrates and affected the foldability of the kirigami structure. However, our folding method could accurately fold the hinges in this situation. Finally, as a demonstration, we fabricated a kiri-origami LED matrix display with more than 500 hinges. The results indicate that kiri-origami structures are feasible for creating stretchable electronic devices with rigid electronic elements and large-area structures. © The Author(s) 2025.

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Variational Onsager Neural Networks (VONNs): A thermodynamics-based variational learning strategy for non-equilibrium PDEs

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arXiv 2021年

作者： Huang, Shenglin He, Zequn Chem, Bryan Reina, Celia Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania PhiladelphiaPA19104 United States Department of Materials Science and Engineering University of Pennsylvania PhiladelphiaPA19104 United States

We propose a thermodynamics-based learning strategy for non-equilibrium evolution equations based on Onsager's variational principle, which allows to write such PDEs in terms of two potentials: the free energy and the dissipation potential. Specifically, these two potentials are learned from spatio-temporal measurements of macroscopic observables via proposed neural network architectures that strongly enforce the satisfaction of the second law of thermodynamics. The method is applied to three distinct physical processes aimed at highlighting the robustness and versatility of the proposed approach. These include (i) the phase transformation of a coiled-coil protein, characterized by a non-convex free-energy density;(ii) the one-dimensional dynamic response of a three-dimensional viscoelastic solid, which leverages the variational formulation as a tool for obtaining reduced order models;and (iii) linear and nonlinear diffusion models, characterized by a lack of uniqueness of the free energy and dissipation potentials. These illustrative examples showcase the possibility of learning partial differential equations through their variational action density (i.e., a function instead), by leveraging the thermodynamic structure intrinsic to mechanical and multiphysics problems. Copyright © 2021, The Authors. All rights reserved.

关键词： Free energy

Observation of the dual quantum spin Hall insulator by density-tuned correlations in a van der Waals monolayer

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arXiv 2024年

作者： Tang, Jian Ding, Thomas Siyuan Chen, Hongyu Gao, Anyuan Qian, Tiema Huang, Zumeng Sun, Zhe Han, Xin Strasser, Alex Li, Jiangxu Geiwitz, Michael Shehabeldin, Mohamed Belosevich, Vsevolod Wang, Zihan Wang, Yiping Watanabe, Kenji Taniguchi, Takashi Bell, David C. Wang, Ziqiang Fu, Liang Zhang, Yang Qian, Xiaofeng Burch, Kenneth S. Shi, Youguo Ni, Ni Chang, Guoqing Xu, Su-Yang Ma, Qiong Department of Physics Boston College Chestnut HillMA United States Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore Singapore Department of Chemistry and Chemical Biology Harvard University CambridgeMA United States Department of Physics and Astronomy and California NanoSystems Institute University of California Los Angeles Los AngelesCA United States Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China Department of Materials Science and Engineering Texas A&M University College StationTX United States Department of Physics and Astronomy University of Tennessee KnoxvilleTN United States Min H. Kao Department of Electrical Engineering and Computer Science University of Tennessee KnoxvilleTN United States Research Center for Electronic and Optical Materials National Institute for Materials Science Tsukuba Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science Tsukuba Japan Harvard John A. Paulson School of Engineering and Applied Sciences The Center for Nanoscale system Harvard University CambridgeMA United States Department of Physics Massachusetts Institute of Technology CambridgeMA United States CIFAR Azrieli Global Scholars program CIFAR Toronto Canada

The convergence of topology and correlations represents a highly coveted realm in the pursuit of novel quantum states of matter [1, 2]. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order [3- 10], not possible in quantum Hall and Chern insulator systems. However, the QSH insulator with quantized edge conductance remains rare, let alone that with significant correlations. In this work, we report a novel dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator that aligns with single-particle band structure calculations, manifesting enhanced nonlocal transport and quantized helical edge conductance. Interestingly, upon introducing electrons from charge neutrality, TaIrTe4 only shows metallic behavior in a small range of charge densities but quickly goes into a new insulating state, entirely unexpected based on TaIrTe4's single-particle band structure. This insulating state could arise from a strong electronic instability near the van Hove singularities (VHS), likely leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state, marked by the revival of nonlocal transport and quantized helical edge conduction. Our observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands via CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism [3-5, 11, 12]. Copyright © 2024, The Authors. All rights reserved.

关键词： Charge density waves