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Computing grain boundary diagrams of thermodynamic and mechanical properties

npj Computational Materials 2021年第1期7卷 1442-1453页

作者： Chongze Hu Yanwen Li Zhiyang Yu Jian Luo Department of Nanoengineering University of California San DiegoLa JollaCA 92093USA Program of Materials Science and Engineering University of California San DiegoLa JollaCA 92093USA State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou University350002 FuzhouFujianP.R.China Department of Physics Southern University of Science and TechnologyShenzhenGuangdong 518055P.R.China

Computing the grain boundary(GB)counterparts to bulk phase diagrams represents an emerging research *** a classical embrittlement model system Ga-doped Al alloy,this study demonstrates the feasibility of computing temperature-and composition-dependent GB diagrams to represent not only equilibrium thermodynamic and structural characters,but also mechanical ***,hybrid Monte Carlo and molecular dynamics(MC/MD)simulations are used to obtain the equilibrium GB structure as a function of temperature and *** GB structures are validated by aberrationcorrected scanning transmission electron ***,MD tensile tests are performed on the simulated equilibrium GB *** diagrams are computed for not only GB adsorption and structural disorder,but also interfacial structural and chemical widths,MD ultimate tensile strength,and MD tensile *** study suggests a research direction to investigate GB composition–structure–property relationships via computing GB diagrams of thermodynamic,structural,and mechanical(or potentially other)properties.

关键词： grain toughness alloy

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Structural changes induced by electric currents in a single crystal of Pr2CuO4

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Physical Review Materials 2023年第8期7卷 083803-083803页

作者： Susmita Roy Feng Ye Zachary Morgan Kabir Mathur Anish Parulekar Syed I. A. Jalali Yu Zhang Gang Cao Nobu-Hisa Kaneko Martin Greven Rishi Raj Dmitry Reznik Department of Physics University of Colorado at Boulder Boulder Colorado 80309 USA Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge Tennessee 37830 USA Materials Science and Engineering Program Department of Mechanical Engineering University of Colorado Boulder Boulder Colorado 80309 USA National Institute of Advanced Industrial Science and Technology (AIST) Tsukuba Ibaraki 305-8563 Japan School of Physics and Astronomy University of Minnesota Minneapolis Minnesota 55455 USA Center for Experiments on Quantum Materials University of Colorado at Boulder Boulder Colorado 80309 USA

We demonstrate an approach to the structural and electronic property modification of perovskites, focusing on Pr2CuO4, an undoped parent compound of a class of electron-doped copper-oxide superconductors. Currents were passed parallel or perpendicular to the copper oxygen layers with the voltage ramped up until a rapid drop in the resistivity was achieved, a process referred to as “flash.” The current was then further increased tenfold in current-control mode. This state was quenched by immersion into liquid nitrogen. Flash can drive many compounds into different atomic structures with new properties, whereas the quench freezes them into a long-lived state. Single-crystal neutron diffraction of as-grown and modified Pr2CuO4 revealed a 10×10 superlattice due to oxygen-vacancy order. The diffraction peak intensities of the superlattice of the modified sample were significantly enhanced relative to the pristine sample. Raman-active phonons in the modified sample were considerably sharper. Measurements of electrical resistivity, magnetization, and two-magnon Raman scattering indicate that the modification affected only the Pr-O layers, but not the Cu-O planes. These results point to enhanced oxygen-vacancy order in the modified samples well beyond what can be achieved without passing electrical current. Our work opens a new avenue toward electric field/quench control of structure and properties of layered perovskite oxides.

关键词： Electrical properties Electroluminescence Magnetic order Magnetic susceptibility Superconductivity

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Numerical Experiment of Adding Patch Elements to X-band Microstrip Antennas

Numerical Experiment of Adding Patch Elements to X-band Micr...

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International RF and Microwave Conference, RFM

作者： Yusnita Rahayu Anhar Saktioto Irsan Taufik Ali Yussi Perdana Saputera M Novriza Teguh Praludi Department of Electrical Engineering Faculty of Engineering Universitas Riau Pekanbaru Indonesia Physics Dept. FMIPA Universitas Riau Pekanbaru Indonesia Doctoral Defense Post Graduate Program Universitas Brawijaya Malang Indonesia National Research and Innovation Agency Indonesia

This paper compares single microstrip antenna designs and microstrip arrays used for Manpack Radar with X-band frequency. Antenna array configurations were investigated for 1x2, 1x4, and 1x32 elements. A gain increase is required for each additional patch element. Patch dimensions are set at 9.17 x 10.10 x 0.035 mm. The parameters needed are X-Band frequency with gain >15 dBi, beamwidth angle of ≤5°, and bandwidth of more than 60 MHz. The simulation results show a good match with the target required for the 9.3 GHz frequency. The largest gain value numerically is obtained on the antenna with 32 patches, which is 17.1 dBi.

关键词： Radio frequency Microstrip antenna arrays Azimuth Simulation Microstrip antennas Radar Bandwidth

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Vibration Energy Harvesting: A Review on Trends, Challenges & Future Direction

Vibration Energy Harvesting: A Review on Trends, Challenges ...

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IEEE International Conference on Emerging & Sustainable Technologies for Power & ICT in a Developing Society (NIGERCON)

作者： Sunday A. Afolalu Temitayo S. Ogedengbe Moses E. Emetere Stella I. Monye Monye N. Snow Dept. of Mechanical and Mechatronics Engineering Department Afe Babalola University Ado-Ekiti Nigeria Dept. of Mechanical Science University Johannesburg South Africa Dept. of Mechanical Engineering Department Nile University of Nigeria Abuja Dept. of Physics Program Bowen University Iwo Osun State Nigeria Dept. of Information Communication Technology University of Delta Agbor Delta State Nigeria

ISBN: (数字)9798331542559

ISBN: (纸本)9798331542566

The worldwide need for sustainable energy solutions has continued to attract the attention of researchers. One vital means for such provision is the harvesting of energy using various methods. This study therefore reviews the recent trends in energy harvesting. Methods such as vibration energy harvesting as well as electrostatic energy harvesting and their applications have been thoroughly discussed. The study also reviewed the challenges with this energy harvesting methods and finally concludes with the future directions of this topic. It is believed that the generation of energy if greatly boosted will drive the economy of any state and ultimately result in wealth generation for the economy.

关键词： Vibrations Humanities Electric potential Reviews Developing countries Market research Energy harvesting Electrostatics

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Detailed dynamics of a moving magnetic skyrmion lattice in MnSi observed using small-angle neutron scattering under an alternating electric current flow

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Physical Review B 2024年第1期110卷 014431-014431页

作者： D. Okuyama M. Bleuel Q. Ye J. Krzywon N. Nagaosa A. Kikkawa Y. Taguchi Y. Tokura J. D. Reim Y. Nambu T. J. Sato Institute of Multidisciplinary Research for Advanced Materials (IMRAM) Institute of Materials Structure Science (IMSS) National Institute of Standards and Technology 100 Bureau Drive Gaithersburg Maryland 20899-8562 USA Department of Materials Science and Engineering (CEMS) Wako 351-0198 Japan Fundamental Quantum Science Program TRIP Headquarters RIKEN Wako 351-0198 Japan Tokyo College and Department of Applied Physics (IMR) Organization for Advanced Studies FOREST

Lattice formation of swirling textures is ubiquitous in solid-state materials, such as a magnetic skyrmion lattice in chiral magnets. In the magnetic skyrmion lattices, their moving states and dynamics under external perturbations are still unrevealed, although a detailed understanding of the dynamics is crucial to realizing spintronic applications, such as magnetic domain-wall racetrack memory [Parkin et al., Science 320, 190 (2008); Fert et al., Nat. Nanotechnol. 8, 152 (2013)]. Here, we report in detail on the transient state of a moving magnetic skyrmion lattice in bulk single-crystalline MnSi under alternating current (AC) using small-angle neutron scattering. A rotation and concomitant broadening of the spot width in the azimuthal direction of the magnetic skyrmion reflections originating from the plastic deformation of the magnetic skyrmion lattice were found only at low AC frequencies [Okuyama et al., Commun. Phys. 2, 79 (2019)], whereas above the threshold AC frequency (ft∼0.12Hz) the rotation was not observed, and the spot width becomes sharper. The observed complex response of the magnetic skyrmion reflections can be explained by the change in dislocation density in the magnetic skyrmion lattice. At frequencies higher than ft, the magnetic skyrmions oscillate removing the dislocations, indicating that the dislocation density is controlled by the AC frequency.

关键词： Magnetic texture Topological defects Chiral magnets Neutron diffraction

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Outcoupling Hyperbolic Modes from Aligned Carbon Nanotube Films

Outcoupling Hyperbolic Modes from Aligned Carbon Nanotube Fi...

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CLEO: QELS_Fundamental Science, QELS 2022

作者： Jerome, Bryant Prasad, Ciril S. Doumani, Jacques Dewey, Oliver S. Baydin, Andrey Pasquali, Matteo Kono, Junichiro Gao, Weilu Alabastri, Alessandro Naik, Gururaj V. Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Chemical and Biomolecular Engineering Rice University HoustonTX77005 United States Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Chemistry Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Electrical and Computer Engineering University of Utah Salt Lake CityUT84112 United States

Aligned carbon nanotube films make an excellent hyperbolic material platform in the infrared. Here, we experimentally demonstrate the presence of high-k modes in aligned carbon nanotube films and outcouple them to fre... 详细信息

ISBN: (纸本)9781557528209

关键词： Carbon films

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Early and advanced crystallization stages in lithia-alumina-silica glasses nucleated by ZrO2

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Ceramics International 2025年

作者： Revelo, Raúl Julián Souza, Mauricio Lima Pena, Rafaella Bartz Yoshida, Satoshi Zanotto, Edgar Dutra Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil São Carlos Institute of Physics University of São Paulo SP São Carlos13566-590 Brazil Materials Integration Laboratories AGC Inc 1-1 Suehiro-Cho Tsurumi-Ku Kanagawa Yokohama230-0045 Japan

ZrO2 is one of the most effective and widely used nucleating agents in various families of glass-ceramics;however, its detailed mechanism remains a subject of debate. Understanding its nucleation mechanism requires a thorough analysis of microstructural evolution and the identification of factors influencing this process. This study investigates the effects of ZrO2 incorporation on the internal nucleation and microstructural evolution in stoichiometric LAS (Li2O·Al2O3·nSiO2) glass-ceramics of varying composition. Glasses with different SiO2 molar ratios (n = 2, 4, 5, and 6) were prepared with ZrO2 additions of 3.0 and 3.5 mol%. Several thermal treatments were employed, followed by characterization using XRD, SEM, STEM, and Raman spectroscopy. The results indicate that a minimum of 3.5 mol% ZrO2 is required to induce internal nucleation in LAS glasses with n = 4, 5, and 6. In these compositions, Zr-enriched regions formed through liquid-liquid phase separation serve as preferential sites for ZrO2 crystal precipitation, which subsequently induces the nucleation of β-quartz solid solution. Upon further treatment at higher temperatures, this metastable phase transforms into β-spodumene or its solid solution. As expected, increasing SiO2 content enhances glass network polymerization, as evidenced by the increased presence of Q3 species in Raman spectroscopy, leading to higher characteristic temperatures of glass transition and peak crystallization in DSC analyses. A higher SiO2 content results in fewer but larger crystals, whereas a lower SiO2 content promotes a higher number density of crystals within the glass matrix. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Glass ceramics

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CO2 Capture Using Silica-Immobilized Dicationic Ionic Liquids with Magnetic and Non-Magnetic Properties

SSRN

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SSRN 2024年

作者： Duarte, Evandro Bernard, Franciele Moreira Dos Santos, Leonardo Polesso, Bárbara B. Duczinski, Rafael Forneck, Vitor Geshev, Julian Einloft, Sandra Post-Graduation Program in Materials Engineering and Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil School of Technology Pontifical Catholic University of Rio Grande do Sul – PUC RS Brazil Institute of Physics Federal University of Rio Grande do Sul RS Porto Alegre Brazil

The need to find alternative materials to replace aqueous amine solutions for CO2 capture in post-combustion technologies is pressing. This study assesses the CO2 sorption capacity and CO2/N2 selectivity of three dicationic ionic liquids with distinct anions immobilized in commercial mesoporous silica support (SBA-15). The samples were characterized by UART-FTIR, NMR, Raman, FESEM, TEM, TGA, Magnetometry (VSM), BET and BJH. The highest CO2 sorption capacity and CO2/N2 selectivity were obtained for sample SBA@DIL_2FeCl4 [at 1 bar and 25°C;57.31 (±0.02) mg CO2/g;12.27 (±0.72)]. The results were compared to pristine SBA-15 and revealed a similar sorption capacity, indicating that the IL has no impact on the silicás CO2 sorption capacity. On the other hand, the selectivity was improved by approximately 3.8, demonstrating the ionic liquid´s affinity for the CO2 molecule. The material underwent multiple sorption/desorption cycles and proved to be stable and a promising option for use in industrial CO2 capture processes. © 2024, The Authors. All rights reserved.

关键词： Carbon dioxide

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Analysis and Design of Metasurface Antennas Based on Temporal Metastructures

Analysis and Design of Metasurface Antennas Based on Tempora...

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European Conference on Antennas and Propagation, EuCAP

作者： L. Stefanini D. Ramaccia M. Barbuto M. Karamirad M. Longhi A. Monti S. Vellucci A. Toscano A. Alù V. Galdi F. Bilotti “Roma Tre” University Rome Italy “Niccolò Cusano” University Rome Italy Photonics Initiative Advanced Science Research Center New York New York USA Physics Program Graduate Center City University of New York New York NY USA Department of Engineering University of Sannio Benevento BN Italy

In this contribution, we present the analysis and design of a novel class of metasurface-based antennas, whose radiative capabilities are enabled by temporal (time-switched) metamaterials. In particular, we consider a thin metasurface supporting the propagation of a surface wave that can switch instantaneously from a finite capacitive value of the surface impedance to an open circuit, resulting in a temporal interface. We demonstrate that after the temporal switch of the metasurface properties, the surface wave is instantaneously coupled to free space realizing a highly directive beam in end-fire direction. Thanks to wavenumber conservation across a temporal interface, we demonstrate that the proposed metasurface-based antenna can radiate at a much higher frequency with respect to the source frequency. Analytical formulations and numerical simulations are provided to predict and verify the frequency upshift and the radiation characteristics of the proposed novel antenna.

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Hydrogen Powered Fuel Cell Systems - A Review

Hydrogen Powered Fuel Cell Systems - A Review

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IEEE International Conference on Emerging & Sustainable Technologies for Power & ICT in a Developing Society (NIGERCON)

作者： Sunday A. Afolalu Temitayo S. Ogedengbe Moses E. Emetere Stella I. Monye Monye N. Snow Dept. of Mechanical and Mechatronics Engineering Department Afe Babalola University Ado-Ekiti Nigeria Dept. of Mechanical Science University Johannesburg South Africa Dept. of Mechanical Engineering Department Nile University of Nigeria Abuja Dept. of Physics Program. Bowen University Iwo Osun State Nigeria Dept. of Information Communication Technology University of Delta Agbor Delta State Nigeria

ISBN: (数字)9798331542559

ISBN: (纸本)9798331542566

The urgent need for sustainable energy sources has fuelled research into alternative power generation technologies. Among these, hydrogen fuel cells have emerged as promising candidates due to their high energy efficiency and zero-emission profile. This study presents a review on hydrogen energy and fuel cell. The design principles for fuel cells, hydrogen production methods, hydrogen storage technologies and the integration of fuel cells into power systems have been discussed. The review concludes with a discussion on technological advances in fuel cell materials and environmental impacts/sustainability of hydrogen fuel cells.

关键词： Renewable energy sources Humanities Hydrogen storage Reviews Hydrogen Fuel cells Production Power systems Sustainable development Power generation

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