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arXiv 2023年

作者： Camarasa-Gómez, María Ramasubramaniam, Ashwin Neaton, Jeffrey B. Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts Amherst AmherstMA01003 United States Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States

The accurate description of electronic properties and optical absorption spectra is a long-standing challenge for density functional theory. Recently, the introduction of screened range-separated hybrid (SRSH) functionals for solid-state materials has allowed for the calculation of fundamental band gaps and optical absorption spectra that are in very good agreement with many-body perturbation theory. However, since solid-state SRSH functionals are typically tuned to reproduce the properties of bulk phases, their transferability to low-dimensional structures, which experience substantially different screening than in the bulk, remains an open question. In this work, we explore the transferability of SRSH functionals to several prototypical van der Waals materials, including transition-metal sulfides and selenides, indium selenide, black phosphorus, and hexagonal boron nitride. Considering the bulk and a monolayer of these materials as limiting cases, we show that the parameters of the SRSH functional can be determined systematically, using only the band-edge quasiparticle energies of these extremal structural phases as fitting targets. The resulting SRSH functionals can describe both electronic bandstructures and optical absorption spectra with accuracy comparable to more demanding ab initio many-body perturbation theory (GW and Bethe-Salpeter equation) approaches. Selected examples also demonstrate that the SRSH parameters, obtained from the bulk and monolayer reference structures, display good accuracy for bandstructures and optical spectra of bilayers, indicating a degree of transferability that is independent of the fitting procedure. Copyright © 2023, The Authors. All rights reserved.

关键词： Transition metals

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DRYING OF REFRACTORY CASTABLES - HOW COMPLEX THE MODELLING NEEDS TO BE? A NUMERICAL AND EXPERIMENTAL STUDY 17

DRYING OF REFRACTORY CASTABLES - HOW COMPLEX THE MODELLING N...

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17th Unified International Technical Conference on Refractories, UNITECR 2022

作者： Moreira, M.H. Pont, S. Dal Ausas, R.F. Cunha, T.M. Luz, A.P. Pandolfelli, V.C. Federal University of Sao Carlos Graduate Program in Materials Science and Engineering SP Sao Carlos Brazil CNRS Grenoble INP 3SR Université Grenoble Alpes Grenoble38000 France Institute of Mathematical and Computer Sciences University of São Paulo SP São Carlos13566-590 Brazil

Calcium aluminate cement (CAC)bonded castables have numerous benefits when compared to monolithic refractories. Their main drawback is their long initial heating, when the physical and chemically-bonded water are released. If the mass flux of water to the ambient is lower than the vapor generation, the gas pressure can increase well above the material's strength resulting in cracks and spalling of the ceramic lining. In order to avoid this, optimized heat up curves are needed, and one promising methodology by using numerical models. Most of these calculations are based on tools used for simulating Portland cement concrete structures on fire and they vary both in complexity and their basic assumptions. Thus, the main question that remains is how complex such models need to be in order to capture the fundamental aspects of this phenomenon. The present work aimed to solve this issue by implementing multiple numerical tools reported in the literature with distinct complexity levels and fundamental assumptions and by also conducting neutron tomography tests on a CAC-bonded castable. It was possible to see that the pressure values predicted by such methodologies are equivalent and the water content predicted is qualitatively similar within the models and with the experimental values, indicating that the simplest approach might be used for predicting the castables' drying. © 2022 Unified International Technical Conference on Refractories, UNITECR 2022 - Proceedings. All rights reserved.

关键词： Portland cement

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Unraveling the Cr₂N Precipitation and Its Negative Effect on the Corrosion Resistance of Friction Stir Welded UNS S32760 Super Duplex Stainless Steel

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Surfaces and Interfaces 2025年 71卷

作者： Vacchi, G.S. de Carvalho, W.S. Meinhardt, C.P. Bergmann, L.A. Amancio-Filho, S.T. Rovere, C.A.D. Munir Rachid Corrosion Laboratory Department of Materials Engineering Federal University of São Carlos Rodovia Washington Luis Km 235 SP São Carlos 13565-905 Brazil Graduate Program in Materials Science and Engineering Federal University of São Carlos Brazil Institute of Materials Science Joining and Forming BMK Endowed Professorship for Aviation Graz University of Technology – TU Graz Kopernikusgasse 24/1 Graz 8010 Austria Department of Mechanical Engineering Federal University of Pampa Avenida Tiarajú 810 RS Alegrete Brazil Helmholtz-Zentrum Hereon Institute of Materials Mechanics Solid State Materials Processing Max-Planck-Straße 1 Geesthacht Germany

The root surface of a friction stir welded super duplex stainless steel (UNS S32760) was thoroughly characterized in this study. The findings revealed a refined grain structure and a conspicuous increase of 50 HV_0.3 in the Root's hardness. Interestingly, the volume fraction of the ferrite phase remained largely unchanged. Rapid cooling in the welding process led to the Cr₂N precipitation at the ferrite/ferrite grain boundaries in the root area, significantly increasing sensitization, reducing localized corrosion resistance under high electrode potentials in a neutral pH saline environment, and adversely affecting root passivity in a hydrochloric acid environment compared to the base metal. © 2025

关键词： Friction stir welding Localized corrosion Polarization Sensitization Super duplex stainless steel

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Terahertz phonon polariton concentrator based on perovskite oxides

Terahertz phonon polariton concentrator based on perovskite ...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Rui Xu Tong Lin Jiaming Luo Xiaotong Chen Elizabeth R. Blackert Alyssa R. Moon Khalil M. JeBailey Hanyu Zhu Department of Materials Science and Nano Engineering Rice University Houston U.S.A. Applied Physics Graduate Program Rice University Houston U.S.A. Nanotechnology Research Experience for Undergraduates (Nano REU) Program Rice University Houston U.S.A.

We report the experimental demonstration of surface phonon-polaritonic devices in a broad spectral range of 7-13 THz based on SrTiO 3 . We designed planar ultrafast concentrators that amplifies transient electric fiel... 详细信息

ISBN: (纸本)9781957171258

关键词： Concentrators Electric fields Fast Fourier transforms Field enhancement Fused silica Second harmonic generation

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Designing of Fe2O3/GO heterostructure with enhanced photocatalytic activity and biological applications

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Nanotechnology for Environmental engineering 2021年第3期6卷 1-14页

作者： Ramesh, Abhilash Mavinakere Gangadhar, Akshatha Chikkamadaiah, Mahendra Nagabhushana, Chandra Mohana Kodandaram, Anju Krishnegowda, Jagadish Mahadevaiah, Kiran Budiguppe Shivanna, Srikantaswamy Department of Studies in Environmental Science University of Mysore Manasagangotri Mysore570 006 India Department of Studies in Botany University of Mysore Manasagangotri Mysore570 006 India Department of Studies in Microbiology University of Mysore Manasagangotri Mysore570 006 India Department of Chemistry Yuvaraja’s College University of Mysore Manasagangotri Mysore570 005 India Department of Civil Engineering Adichuchanagiri Institute of Technology Chikmagalur577 101 India Centre for Materials Science and Technology University of Mysore Vijinana Bhavan Manasagangotri Mysore570 006 India

A systematic method have been followed in Fe2O3/GO heterostructure synthesis via, a facile chemical vapor deposition (C-CVD) and hydrothermal route. The synthesized Fe2O3/GO which performs a single step process of photocatalytic degradation of Eosin Yellow (EY) with hazardless small molecular intermediates obtained. Concurrently, five different heavy metal removal is done under influence of solar radiation when exposed to sunlight. The first-rate antibacterial/fungal activity against Bacillus subtilis (MTCC 121);Staphylococcus aureus (MTCC 7443);Salmonella typhi (MTCC 733);Candida albicans (MTCC 183), Fusarium verticillioides (MTCC 8792). And biocompatibility studies on Human embryonic kidney (HEK-293) cell lines was systematically achieved. This work offers the opportunity to constructing of efficient photocatalyst with excellent biology to a safer environment. Graphic abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Heavy metals

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Toward a comprehensive hypothesis of oxygen-evolution reaction in the presence of iron and gold

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Journal of Energy Chemistry 2024年第2期89卷 172-183,I0005页

作者： Negah Hashemi Jafar Hussain Shah Cejun Hu Subhajit Nandy Pavlo Aleshkevych Sumbal Farid Keun Hwa Chae Wei Xie Taifeng Liu Junhu Wang Mohammad Mahdi Najafpour Department of Chemistry Institute for Advanced Studies in Basic Sciences(IASBS)Zanjan 45137-66731Iran Center for Advanced Mössbauer Spectroscopy Mössbauer Effect Data CenterDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Key Lab of Advanced Energy Materials Chemistry(Ministry of Education) Renewable Energy Conversion and Storage CenterCollege of ChemistryNankai UniversityTianjin 300071China Advanced Analysis Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Institute of Physics Polish Academy of SciencesWarsaw 02-668Poland National and Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Henan UniversityKaifeng 475004HenanChina Center of Climate Change and Global Warming Institute for Advanced Studies in Basic Sciences(IASBS)Zanjan 45137-66731Iran Research Center for Basic Sciences&Modern Technologies(RBST) Institute for Advanced Studies in Basic Sciences(IASBS)Zanjan 45137-66731Iran

This study investigates the effects of Fe on the oxygen-evolution reaction(OER)in the presence of *** distinct areas of OER were identified:the first associated with Fe sites at low overpotential(~330 mV),and the second with Au sites at high overpotential(~870 mV).Various factors such as surface Fe concentration,electrochemical method,scan rate,potential range,concentration,method of adding K_(2)Fe O_(4),nature of Fe,and temperature were varied to observe diverse behaviors during OER for Fe O_(x)H_(y)/*** amounts of Fe ions had a significant impact on OER,reaching a saturation point where the activity did not increase *** electronic interaction between Fe and Au ions was indicated by X-ray photoelectron spectroscopy(XPS)and electron paramagnetic resonance(EPR)*** situ visible spectroscopy confirmed the formation of Fe O_(4)^(2-)during *** situ Mossbauer and surfaceenhanced Raman spectroscopy(SERS)analyses suggest the involvement of Fe-based species as intermediates during the rate-determining step of OER.A lattice OER mechanism based on Fe O_(x)H_(y)was proposed for operation at low *** functional theory(DFT)calculations revealed that Fe oxide,Fe-oxide clusters,and Fe doping on the Au foil exhibited different activities and stabilities during *** study provides insights into the interplay between Fe and Au in OER,advancing the understanding of OER mechanisms and offering implications for the design of efficient electrocatalytic systems.

关键词： DFT calculation Fe/Au electrocatalysis Mechanism Oxygen evolution Water oxidation

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Microscopic picture of paraelectric perovskites from structural prototypes

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Physical Review Research 2022年第1期4卷 L012042-L012042页

作者： Michele Kotiuga Samed Halilov Boris Kozinsky Marco Fornari Nicola Marzari Giovanni Pizzi Theory and Simulation of Materials (THEOS) National Centre for Computational Design and Discovery of Novel Materials (MARVEL) École Polytechnique Fédérale de Lausanne CH-1015 Lausanne Switzerland Designed Material Technologies LLC P.O. Box 14548 Richmond Virginia 23221-9998 USA John A. Paulson School of Engineering and Applied Sciences Harvard University 29 Oxford Street Cambridge Massachusetts 02138 USA Robert Bosch LLC Research and Technology Center Cambridge Massachusetts 02139 USA Department of Physics and Science of Advanced Materials Program Central Michigan University Mt. Pleasant Michigan 48859 USA

We highlight with first-principles molecular dynamics the persistence of intrinsic 〈111〉 Ti off-centerings for BaTiO3 in its cubic paraelectric phase. Intriguingly, these are inconsistent with the Pm3¯m space group often used to atomistically model this phase using density-functional theory or similar methods. Therefore, we deploy a systematic symmetry analysis to construct representative structural models in the form of supercells that satisfy a desired point symmetry but are built from the combination of lower-symmetry primitive cells. We define as structural prototypes the smallest of these that are both energetically and dynamically stable. Remarkably, two 40-atom prototypes can be identified for paraelectric BaTiO3; these are also common to many other ABO3 perovskites. These prototypes can offer structural models of paraelectric phases that can be used for the computational engineering of functional materials. Last, we show that the emergence of B-cation off-centerings and the primitive-cell phonon instabilities is controlled by the equilibrium volume, in turn, dictated by the filler A cation.

关键词： Crystal symmetry Ferroelectricity Structural order parameter Paraelectrics

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Isolated Pt atoms tethered to N-doped MoSx as highly efficient and sustainable hydrogen evolution reaction electrocatalyst

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Applied Surface science 2023年第1期614卷

作者： Lee, Ting-Wei Lo, Ying-Chen Wu, Chia-Hua Ho, Cheng-Yuan Alamani, Bryan G. Chen, Jeng-Lung Chen, Chiaying Department of Environmental Engineering National Chung Hsing University Taichung City402 Taiwan Department of Materials Science and Engineering National Yang Ming Chiao Tung University Hsinchu300 Taiwan Department of Chemical Engineering College of Engineering University of the Philippines Diliman Quezon City1101 Philippines Environmental Engineering Program College of Engineering University of the Philippines Diliman Quezon City1101 Philippines National Synchrotron Radiation Research Center Hsinchu30076 Taiwan

In this work, synergistic NH4+ intercalation and nitrogen-containing molecule doping realize a crystalline-to-amorphous (i.e., MoSx) structure transition with enhanced HER reactivity and superior stability obtained via structural distortion and abundant active sites. The applied N dopants partially replace the bridging S22− and form Mo-N bonds, where the alkyl N-dopant tetramethylammonium chloride (TEA) achieves the most effective doping. The HER activity increases with an increasing number of bridging S22− and MoⅤ species, both of which contribute to advance electrocatalytic performance. Furthermore, N-doped MoSx is identified as an exceptional stabilizing platform to anchor single Pt atoms (PtSA) through Pt-S bonding, rendering MoSx/TEA/PtSA a highly promising electrocatalyst. MoSx/TEA/PtSA achieved comparable performance to that of the benchmark Pt/C catalyst (i.e., a cathodic current density of 10 mA·cm−2 at overpotential of 97 mV) with much lower loading of Pt (0.67 wt%). Theoretical calculations based on density functional theory indicate that Pt atoms and Pt-adjacent sulfur atoms act as active sites. The superior interfacial electron transfer and thus HER performance of MoSx/TEA/PtSA arises from (1) boosted electronic metal-support interaction through Pt-S bonds and (2) enhanced H adsorption ability of Pt-adjacent sulfur atoms due to Pt coordination. © 2022 Elsevier B.V.

关键词： Doping (additives)

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Introducing self-healing properties to polyethersulfone (PES) membrane via poly(vinyl alcohol)/ polyacrylic acid (PVA/PAA) surface coating

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Chemosphere 2024年 349卷 140772页

作者： Lim, Yi Heng Wong, Eng Cheong Chong, Woon Chan Mohammad, Abdul Wahab Koo, Chai Hoon Lau, Woei Jye Department of Chemical Engineering Lee Kong Chian Faculty of Engineering and Science Universiti Tunku Abdul Rahman Sungai Long Campus Jalan Sungai Long Cheras Selangor Kajang43000 Malaysia Centre for Advanced and Sustainable Materials Research Universiti Tunku Abdul Rahman Sungai Long Campus Jalan Sungai Long Cheras Selangor Kajang43000 Malaysia Chemical and Water Desalination Program College of Engineering University of Sharjah Sharjah27272 United Arab Emirates Chemical Engineering Programme Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia Selangor Bangi43600 Malaysia Faculty of Chemical and Energy Engineering Universiti Teknologi Malaysia Johor Johor Bahru81310 Malaysia

During membrane filtration, it is inevitable that a membrane will experience physical damage, leading to a loss of its integrity and a decrease in separation efficiency. Hence, the development of a water-responsive membrane capable of healing itself autonomously after physical damage is significantly important in the field of water filtration. Herein, a water-enabled self-healing composite polyethersulfone (PES) membrane was synthesized by coating the membrane surface using a mixed solution composed of poly (vinyl alcohol) and polyacrylic acid (PVA-PAA). The self-healing efficiency of the coated PES membrane was examined based on the changes in water flux at three stages which are pre-damaged, post-damaged, and post-healing. The self-healing process was initiated by the swelling of the water-responsive PVA and PAA, followed by the formation of reversible hydrogen bonds, completing the self-healing process. The coated PES membrane with three layers of PVA-PAA coatings (at 3:1 ratio) demonstrated high water flux and remarkable self-healing efficiency of up to 98.3%. The self-healing capability was evidenced by the morphology of the membrane observed via scanning electron microscope (SEM). The findings of this investigation present a novel architecture approach for fabricating self-healing membranes using PVA-PAA, in addition to other relevant parameters as reported. © 2023 Elsevier Ltd

关键词： Membranes

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3DDGD: 3D Deepfake Generation and Detection Using 3D Face Meshes

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IEEE Access 2025年 13卷 107429-107441页

作者： Hichem Felouat Huy H. Nguyen Junichi Yamagishi Isao Echizen Informatics Program The Graduate University for Advanced Studies SOKENDAI Hayama Kanagawa Japan Information and Society Research Division National Institute of Informatics (NII) Tokyo Japan Digital Content and Media Sciences Research Division National Institute of Informatics (NII) Tokyo Japan Department of Information and Communication Engineering Graduate School of Information Science and Technology The University of Tokyo Tokyo Japan

3D face technology is revolutionizing various fields by providing superior security and realism compared with 2D methods. In biometric authentication, 3D facial features serve as unique, hard-to-forge identifiers, improving accuracy in facial recognition for border control and criminal identification. Additionally, 3D avatars enhance virtual interactions. In this study, we aimed to strengthen 3D facial biometric systems against deepfakes. Key contributions include proving the superior protection of 3D faces over 2D ones, creating a dataset of real and fake 3D faces, and developing advanced models for accurate 3D deepfake detection. We evaluated our models for generalization to other datasets and stability when changing training data. Our experiments used the mesh multi-layer perceptron model for deepfake detection along with self-attention mechanisms and the newly introduced TabTransformer model. Results indicate that 3D face meshes greatly improve security by distinguishing real faces from deepfakes. Future work will focus on enhancing detection tools and integrating geometric features with facial textures for more accurate 3D deepfake detection. The dataset and models are publicly available on GitHub, excluding licensed elements: https://***/hichemfelouat/3DDGD

关键词： Three-dimensional displays Face recognition Deepfakes Solid modeling Shape Image reconstruction Faces Point cloud compression Accuracy Feature extraction

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