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arXiv 2025年

作者： Mai, Han Lin Cui, Xiang-Yuan Hickel, Tilmann Neugebauer, Jörg Ringer, Simon P. Computational Materials Design Department Max Planck Institute for Sustainable Materials Max-Planck-Straße 1 40237 Germany School of Aerospace Mechanical and Mechatronic Engineering Australian Centre for Microscopy and Microanalysis The University of Sydney NSW2006 Australia BAM Federal Institute for Materials Research and Testing Berlin12489 Germany

Segregation of alloying elements and impurities at grain boundaries (GBs) critically influences material behavior by affecting cohesion. In this study, we present an ab initio high-throughput evaluation of segregation energies and cohesive effects for all elements in the periodic table (Z = 1–92, H–U) across six model ferritic iron GBs using density functional theory (DFT). From these data, we construct comprehensive elemental maps for solute segregation tendencies and cohesion at GBs, providing guidance for segregation engineering. We systematically assess the cohesive effects of different elements in all segregating positions along multiple fracture paths with a quantum-chemistry bond-order method as well as a modified Rice-Wang theory of interfacial cohesion. The effects of segregants on the cohesion of GBs are shown to vary drastically as a function of site character, and hence their induced cohesive effects must be considered as a thermodynamic average over the spectral energy distribution. Thus, models that overlook these aspects may fail to accurately predict the impacts of varying alloying concentrations, thermal processing conditions, or GB types. The insights presented here, along with our accompanying dataset, are expected to advance our understanding of GB segregation in steels and other materials. © 2025, CC BY-NC-ND.

关键词： Alloying elements

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Unique Temperature-Dependence of Polarization Switching Paths in Ferroelectric BaTiO3: A Molecular Dynamics Simulation Study

SSRN

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SSRN 2025年

作者： Azuma, Hikaru Ogawa, Tomohiro Ogata, Shuji Kobayashi, Ryo Uranagase, Masayuki Tsuzuki, Takahiro Wendler, Frank WW-8 Materials Simulation Germany Graduate School of Engineering Nagoya Institute of Technology Nagoya466-8555 Japan Laboratory for Computational Molecular Design RIKEN Center for Biosystems Dynamics Research Kobe650-0047 Japan Department of Material Science Friedrich-Alexander University of Erlangen-Nürnberg Fürth90762 Germany

Polarization switching in ferroelectrics under an external electric field is crucial for their application in memory devices and actuators. Experimental research has identified two distinct polarization switching processes in tetragonal BaTiO3 (BT) when applying an external electric field in the direction opposite to the polarization: (i) direct inversion of polarization and (ii) two-step inversion composed of two-times 90° rotation of polarization. In this study, we performed molecular dynamics simulations using accurate shell-model interatomic potential to unravel the mechanisms distinguishing these two processes. We established updated shell-model parameters by fitting them to various physical properties, including phonon dispersions obtained from density-functional theory utilizing an appropriate combination of meta-generalized gradient approximation exchange-correlation functional and dispersion force correction. When applying an external electric field in the –c -direction to a tetragonal BT crystal polarized along c-direction, the polarization switches through two-times 90° rotation at low temperatures and through formation of a polarization-inverted nucleus at high temperatures. The coercive field Ec|| along –c-direction increases with temperature at low temperatures, while decreases at high temperatures. In contrast, when the external electric field is applied along b-direction, the coercive field Ec⊥ is smaller than Ec|| and increases monotonically with temperature. The polarization rotated in b-direction without nucleation along with deformation through orthorhombic structure. Unique temperature dependencies of Ec|| and Ec⊥ are attributed to the pronounced fluctuations in local polarizations perpendicular to the system polarization and the proximity of temperature to the orthorhombic-tetragonal transition point. Present findings offer essential information in designing BT-based ferroelectrics with doping. © 2025, The Authors. All rights reserved.

关键词： Perovskite

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3D-Printed Stainless Steel Electrodes for Advancing Mems Microbial Fuel Cells Toward Sustainable on-chip Energy

3D-Printed Stainless Steel Electrodes for Advancing Mems Mic...

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IEEE International Conference on Micro Electro Mechanical Systems

作者： Anwar Elhadad Guangfa Li Jiaqi Yang Dehao Liu Seokheun Choi Department of Electrical & Computer Engineering Bioelectronics & Microsystems Laboratory State University of New York at Binghamton Binghamton New York USA Department of Mechanical Engineering Integrated Computational Materials Design Lab State University of New York at Binghamton Binghamton New York USA Center for Research in Advanced Sensing Technologies and Environmental Sustainability State University of New York at Binghamton Binghamton New York USA

ISBN: (数字)9798331508890

ISBN: (纸本)9798331508906

This study introduces a stainless steel microbial anode fabricated via advanced laser powder bed fusion, marking a transformative step in microbial fuel cell (MFC) technology. By leveraging this cutting-edge metal 3D printing approach, we achieve a 3D microporous structure with superior electrical conductivity, outstanding corrosion resistance in aquatic environments, robust mechanical strength, and adaptability for surface modification—essential attributes for sustainable, high-performance MFCs. The assembled MFC demonstrates unparalleled power output, along with exceptional durability and stability over multiple cycles, outperforming existing MFCs based on alternative 3D-printed substrates. This advancement not only solidifies the role of MFCs as a sustainable energy solution for powering on-chip electronics but also opens new avenues for scalable, cost-effective bioelectronic systems that align with the demands of next-generation technology.

关键词： Powders Catalysts Fuel cells Laser stability Three-dimensional printing System-on-chip Steel Anodes Laser fusion Surface treatment

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A COMPLETE E-PLANE ANALYSIS OF WAVE-GUIDE JUNCTIONS USING THE FINITE-ELEMENT METHOD

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1990年第3期38卷 290-295页

作者： KANELLOPOULOS, VN WEBB, JP Computational Analysis and Design Laboratory Department of Electrical Engineering McGill University Montreal Canada

A complete finite-element analysis of inhomogeneous E-plane waveguide junctions is presented. It is shown that at least two field components are needed for the analysis. This method solves for the three components of the magnetic field in two dimensions and calculates the scattering parameters of the junction. Precalculated matrices are used for fast matrix assembly. Results for a metallic post agree very well with earlier published values. A dielectric post was also analyzed.< >

关键词： Waveguide junctions Finite element methods Dielectrics Rectangular waveguides Magnetic analysis Scattering parameters Transmission line matrix methods Planar waveguides Magnetic fields Assembly

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Global Universal Scaling and Ultra-Small Parameterization in Machine Learning Interatomic Potentials with Super-Linearity

arXiv

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arXiv 2025年

作者： Hu, Yanxiao Sheng, Ye Huang, Jing Xu, Xiaoxin Yang, Yuyan Zhang, Mingqiang Wu, Yabei Ye, Caichao Yang, Jiong Zhang, Wenqing Department of Materials Science and Engineering Southern University of Science and Technology Guangdong Shenzhen518055 China Materials Genome Institute Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials Shanghai University Shanghai200444 China Institute of Innovative Materials Guangdong Provincial Key Lab for Computational Science and Materials Design Southern University of Science and Technology Guangdong Shenzhen518055 China

Using machine learning (ML) to construct interatomic interactions and thus potential energy surface (PES) has become a common strategy for materials design and simulations. However, those current models of machine learning interatomic potential (MLIP) provide no relevant physical constrains, and thus may owe intrinsic out-of-domain difficulty which underlies the challenges of model generalizability and physical scalability. Here, by incorporating physics-informed Universal-Scaling law and nonlinearity-embedded interaction function, we develop a Super-linear MLIP with both Ultra-Small parameterization and greatly expanded expressive capability, named SUS2-MLIP. Due to the global scaling rooting in universal equation of state (UEOS), SUS2-MLIP not only has significantly-reduced parameters by decoupling the element space from coordinate space, but also naturally outcomes the out-of-domain difficulty and endows the potentials with inherent generalizability and scalability even with relatively small training dataset. The nonlinearity-enbeding transformation for interaction function expands the expressive capability and make the potentials super-linear. The SUS2-MLIP outperforms the state-of-the-art MLIP models with its exceptional computational efficiency especially for multiple-element materials and physical scalability in property prediction. This work not only presents a highly-efficient universal MLIP model but also sheds light on incorporating physical constraints into artificial-intelligence-aided materials simulation. Copyright © 2025, The Authors. All rights reserved.

关键词： Scalability

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THE USE OF HIERARCHICAL TRIANGLES IN FINITE-ELEMENT ANALYSIS OF MICROWAVE AND OPTICAL-DEVICES

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IEEE TRANSACTIONS ON MAGNETICS 1991年第5期27卷 4040-4043页

作者： WEBB, JP MCFEE, S Electrical Engineering Department Computational Analysis and Design Laboratory Montreal ONT Canada

Hierarchal triangles are high-order finite elements which permit mixing of orders within the same mesh. They are particularly useful in microwave and optical problems, where the underlying wave-like variation of the field is modelled better by high-order elements than by low-order elements, but where the use of the same order throughout gives an inefficient distribution of degrees of freedom. Fields computed with hierarchal elements are shown for a microstrip patch, two posts in a rectangular waveguide, and a dielectric waveguide feed.

关键词： Finite element methods Microwave devices Optical devices Polynomials Mesh generation Optical waveguides Rectangular waveguides Optical scattering Lagrangian functions Laboratories

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Two-mode terms in Wigner transport equation elucidate anomalous thermal transport in amorphous silicon

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Physical Review B 2025年第9期111卷 094206-094206页

作者： Jin Yang Xueyan Zhu Alan J. H. McGaughey Yee Sin Ang Wee-Liat Ong ZJU-UIUC Institute College of Energy Engineering Zhejiang University Jiaxing Haining Zhejiang 314400 China China Academy of Engineering Physics Software Center for High Performance Numerical Simulation Beijing 100088 China Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Mechanical Engineering Carnegie Mellon University Pittsburgh Pennsylvania 15213 USA Science Mathematics and Technology Singapore University of Technology and Design 487372 Singapore State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou Zhejiang 310027 China

Over the past decades, our understanding of thermal transport in amorphous materials has predominantly relied on the inherently harmonic Allen-Feldman theory, which has been found to be insufficient. In this study, the Wigner transport formalism is adopted to explicitly account for anharmonicity. In studying the thermal transport in amorphous silicon, the results highlight that amorphous materials are not generally computationally equivalent to crystals with disordered primitive cells. A method that leverages the properties of the two-mode terms in the Wigner transport formalism is proposed to predict the bulk thermal conductivity of amorphous materials using finite-size models. In doing so, the need for mode classification schemes required in the Allen-Feldman theory is eliminated, and similarities are discovered between the two-mode terms and the carriers commonly used to describe thermal transport in amorphous materials, i.e., propagons, diffusons, and locons. Two competing trends are identified that shed light on the recently discovered anomalous decrease in the high-temperature thermal conductivity in some amorphous materials.

关键词： Heat transfer

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Spontaneous Donor Defects and Voltage-Assisted Hole Doping in Beta-Gallium Oxides under Multiple Epitaxy Conditions

arXiv

引用

arXiv 2025年

作者： Nie, Chenxi Liu, Kai Ke, Chengxuan Jiang, Xisong He, Yifeng Deng, Yonghong Yan, Yanhua Luo, Guangfu Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen518055 China Shenzhen CAPCHEM Technology Co. Ltd. Shabo Tongfuyu Industry Zone Pingshan District Shenzhen518118 China Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Shenzhen518055 China

Beta-phase gallium oxide (β-Ga2O3) is prone to the spontaneous formation of donor defects but poses a formidable challenge in achieving high-quality p-type doping, mainly due to its exceptionally low valence band maximum (VBM). In this study, we utilize first-principles computations to investigate the origin of spontaneous donor defects in β-Ga2O3 grown by three typical techniques: molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), and halide vapor phase epitaxy (HVPE). Our findings elucidate that the primary donor defects vary with the growth techniques, specifically Gai3+ for MBE, Hi+ and CGa+ for MOCVD, and (2VGa+Gai+2VO)+ and ClO+ for HVPE under unintentionally doped conditions. Employing a theoretically proposed voltage-assisted doping method, we computationally demonstrate that the dominant spontaneous donors can be significantly reduced accompanied by a noticeable increase in acceptors, leading to a stepwise reduction of Fermi level to 0.52, 0.88, and 2.10 eV above VBM for the MOCVD, HVPE, and MBE methods, and a hole concentration of 8.5 × 1017, 8.7 × 1011, and 2.7 × 10-9 cm-3, respectively, at room temperature without the use of external dopants. By introducing Mg doping, we further reduce the Fermi level for both the MBE and HVPE experiments. © 2025, CC BY.

关键词： Fermi level

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EFFICIENT GENERATION OF DIVERGENCE-FREE FIELDS FOR THE FINITE-ELEMENT ANALYSIS OF 3D CAVITY RESONANCES

引用

IEEE TRANSACTIONS ON MAGNETICS 1988年第1期24卷 162-165页

作者： WEBB, JP Computational Analysis and Design Laboratory Department of Electrical Engineering McGill University Montreal Canada

Spurious modes can be eliminated from the finite element solutions of three-dimensional resonant cavities by imposing solenoidality. The addition of a penalty term to the functional has the effect of pushing the spurious modes out of the range of interest. This approach is preferred because it does not destroy matrix sparsity; however, the selection of a suitable penalty parameter is difficult. A method is presented that allows for one penalty parameter per mode instead of one overall and adjusts the parameters automatically as the modes are computed. Results of using the method to analyze empty and dielectric-loaded cavities are presented.< >

关键词： Finite element methods Resonance Dielectrics Electromagnetic waveguides Magnetic fields Laboratories Transmission line matrix methods Electromagnetic scattering Electromagnetic devices Linear particle accelerator

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FINITE-ELEMENT ANALYSIS OF H-PLANE RECTANGULAR WAVE-GUIDE PROBLEMS

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IEE PROCEEDINGS-H MICROWAVES ANTENNAS AND PROPAGATION 1986年第2期133卷 91-94页

作者： WEBB, JP PARIHAR, S Computational Analysis and Design Laboratory Department of Electrical Engineering McGill University Montreal Canada

The equivalent circuit parameters of rectangular waveguide H-plane junctions, bends and obstacles may be found by a two-dimensional finite element method. Results are presented for perfectly conducting and dielectric ... 详细信息

关键词： Waveguides and microwave transmission lines dielectric obstacles Waveguide and microwave transmission line components Other numerical methods perfectly conducting obstacles two-dimensional finite element method equivalent circuit parameters rectangular waveguide H-plane junctions waveguide bend Waveguide and cavity theory waveguide couplers waveguide theory finite element analysis rectangular waveguides

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