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The wave-envelope method and absorbing boundary conditions

IEEE TRANSACTIONS ON MAGNETICS 1997年第2期33卷 1420-1423页

作者： Choi, CTM Webb, JP Computational Analysis and Design Laboratory Electrical Engineering Department McGill University Montreal Canada

An absorbing boundary condition (ABC) is an effective way to truncate the domain of an unbounded electromagnetic scattering problem, to allow it to be solved by the finite element method. However, the boundary on which the ABC is imposed must be separated from the scatterer by a thick layer of space, which can be expensive to model with conventional finite elements. The Wave-Envelope (WE) Method is here used to model the layer of space much more cheaply. Results demonstrate the accuracy and efficiency of this approach.

关键词： Boundary conditions Electromagnetic scattering Acoustic scattering Radar scattering Finite element methods Equations Electromagnetic radiation Electromagnetic analysis Laboratories Radar cross section

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ELIMINATING SPURIOUS MODES IN FINITE-ELEMENT WAVE-GUIDE PROBLEMS BY USING DIVERGENCE-FREE FIELDS

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ELECTRONICS LETTERS 1986年第11期22卷 569-570页

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

Spurious solutions in the finite-element analysis of the modes of waveguides and optical fibres are completely eliminated by the use of fields which are exactly divergence-free. Such fields are themselves computed by ... 详细信息

关键词： optical waveguide theory optical fibres Numerical approximation and analysis finite-element analysis Waveguide and cavity theory spurious modes elimination waveguide theory spurious solutions elimination Interpolation and function approximation (numerical analysis) finite element analysis finite-element waveguide problems divergence-free fields Fibre optics and fibre waveguides Fibre optics

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ADAPTIVE FINITE-ELEMENT ANALYSIS OF MICROWAVE AND OPTICAL-DEVICES USING HIERARCHICAL TRIANGLES

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IEEE TRANSACTIONS ON MAGNETICS 1992年第2期28卷 1708-1711页

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

Adaptive methods using hierarchal triangles can automatically determine a good distribution of free parameters for the finite-element analysis of microwave and optical devices. Such methods avoid repeated mesh-refinement, instead they vary the polynomial order of the elements in different parts of the mesh. A simple yet effective method for hierarchal adaption for high-frequency finite-element analysis is developed and evaluated.

关键词： Finite element methods Microwave devices Optical devices Optical waveguides Polynomials Rectangular waveguides Costs Distributed computing Optical computing Optical design

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EDGE ELEMENTS AND WHAT THEY CAN DO FOR YOU

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IEEE TRANSACTIONS ON MAGNETICS 1993年第2期29卷 1460-1465页

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

Edge elements are finite elements whose degrees of freedom are associated with edges rather than with nodes. They have been used to compute 3D vector electromagnetic fields in both power and microwave engineering. They have several useful properties: they allow the normal component of the vector to be discontinuous from one element to the next;they are better at handling field singularities;they eliminate spurious modes;they permit a unique separation of a vector field into the gradient of a scalar and a remaining part. Various tetrahedral and hexahedral edge elements exist, and triangular and quadrilateral edge elements have been developed for 2D problems.

关键词： Power engineering computing Finite element methods Electromagnetic fields Equations Laboratories Power engineering and energy Boundary conditions Vectors Hydrogen

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design process error-proofing: engineering peer review lessons from NASA

Design process error-proofing: Engineering peer review lesso...

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2004 ASME design engineering Technical Conferences and Computers and Information in engineering Conference

作者： Chao, Lawrence P. Tumer, Irem Ishii, Kosuke Department of Mechanical Engineering Design Division Stanford University Stanford CA 94305-4022 United States Computational Sciences Division NASA Ames Research Center Moffett Field CA 94035-1000 United States

This report describes the state of design reviews observed at NASA and research into improving review practices. There are many types of reviews at NASA. Formal, programmatic project reviews such as the Preliminary design Review and Critical design Review are a required part of every project and mission development. However, the informal and technical engineering peer reviews that support teams' work on such projects are informal, ad hoc, and inconsistent across the organization. The goal of this work is to identify best practices and lessons learned from NASA's review experience, benchmark against industry techniques, and develop methodologies to improve the process. Thus far, the research has determined that the organization, composition, scope, and execution, including the use of information technology and structured design methodologies, of reviews all impact the technical, engineering peer reviews to help NASA work towards error-proofing the design process.

关键词： Process control

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Correction: Materials laboratories of the future for alloys, amorphous, and composite materials (MRS Bulletin, (2025), 50, 2, (190-207), 10.1557/s43577-024-00846-y)

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MRS Bulletin 2025年 1-2页

作者： Banerjee, Sarbajit Meng, Y. Shirley Minor, Andrew M. Zhang, Minghao Zaluzec, Nestor J. Chan, Maria K.Y. Seidler, Gerald McComb, David W. Agar, Joshua Mukherjee, Partha P. Melot, Brent Chapman, Karena Guiton, Beth S. Klie, Robert F. McCue, Ian D. Voyles, Paul M. Robertson, Ian Li, Ling Chi, Miaofang Destino, Joel F. Devaraj, Arun Marquis, Emmanuelle A. Segre, Carlo U. Liu, Huinan H. Yang, Judith C. Momeni, Kasra Misra, Amit Abdolrahim, Niaz Medvedeva, Julia E. Cai, Wenjun Sehirlioglu, Alp Dizbay-Onat, Melike Mehta, Apurva Graham-Brady, Lori Maruyama, Benji Rajan, Krishna Warner, Jamie H. Taheri, Mitra L. Kalinin, Sergei V. Reeja-Jayan, B. Schwarz, Udo D. Simon, Sindee L. Brown, Craig M. Department of Chemistry and Department of Materials Science & Engineering Texas A & M University College Station United States Pritzker School of Molecular Engineering The University of Chicago Chicago United States Department of Materials Science & Engineering University of California Berkeley Berkeley United States National Center for Electron Microscopy Molecular Foundry Lawrence Berkeley National Laboratory Berkeley United States Center for Nanoscale Materials Argonne National Laboratory Lemont United States Department of Physics University of Washington Seattle United States Department of Materials Science & Engineering The Ohio State University Columbus United States Department of Mechanical Engineering and Mechanics Drexel University Philadelphia United States School of Mechanical Engineering Purdue University West Lafayette United States Department of Chemistry University of Southern California Los Angeles United States Department of Chemistry Stony Brook University The State University of New York Stony Brook United States Department of Chemistry University of Kentucky Lexington United States Department of Physics University of Illinois at Chicago Chicago United States Department of Materials Science & Engineering Northwestern University Evanston Bangladesh Department of Materials Science & Engineering University of Wisconsin–Madison Madison United States Department of Materials Science and Engineering University of Pennsylvania Philadelphia United States Department of Mechanical Engineering and Materials Science Duke University Durham United States Department of Chemistry Creighton University Omaha United States Physical and Computational Sciences Directorate Pacific Northwest National Laboratory Richland United States Department of Materials Science & Engineering University of Michigan–Ann Arbor Ann Arbor United States Department of Physics Illinois Institute of Technology Chicago United States Department of Bioengineering and the Mater

This article was updated to correct Minghao Zhang’s affiliation from "Pritzker School of Molecular engineering, The University of Chicago, Chicago, USA" to "Pritzker School of Molecular engineering, The University of Chicago, Chicago, USA;Argonne National Laboratory, Lemont, USA." Argonne National Laboratory was left off the original publication. © The Author(s) 2025.

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Wave-envelope and transformation methods for finite element solution of unbounded electromagnetic wave problems

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IEEE TRANSACTIONS ON MAGNETICS 1996年第3期32卷 886-889页

作者： Choi, CTM Webb, JP Computational Analysis and Design Laboratory Electrical Engineering Department McGill University Montreal QUE Canada

The Wave-Envelope (WE) Method is a technique that has been applied to acoustic problems to model the unbounded domain surrounding an acoustic source. Here it is applied to electromagnetic wave problems. A key feature of the method is that it uses a change of dependent variable to remove the wave-like qualities of the solution and thereby permits the use of arbitrarily large elements in the exterior domain. This makes it possible to apply to wave problems some of the techniques developed for magnetostatics, such as Transformation Methods. These methods map the very large exterior domain into a smaller region which is more easily meshed. The combined Wave-Envelope Transformation Method is applied to two time-harmonic electromagnetic wave problems: radiation of a single cylindrical wave function;and scattering of an incident plane wave by a perfectly-conducting circular cylinder. In both cases the near-zone electric field is compared to the exact solution, for a range of frequencies.

关键词： Finite element methods Electromagnetic scattering Acoustic waves Magnetostatics Electromagnetic radiation Wave functions Acoustic scattering Frequency

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Optimal discretization based refinement criteria for finite element adaption

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IEEE TRANSACTIONS ON MAGNETICS 1996年第3期32卷 1357-1360页

作者： McFee, S Giannacopoulos, D Computational Analysis and Design Laboratory Department of Electrical Engineering McGill University Montreal QUE Canada

One of the major research issues in adaptive finite element analysis is the feedback control system used to guide the adaption, Essentially, one needs to resolve which error data to feedback after each iteration, and how to use it to initialize the next adaptive step. Variational aspects of optimal discretizations for scalar Poisson and Helmholtz systems are used to derive new refinement criteria for adaptive finite element solvers. They are shown to be effective and economical for h-, p- and hp- schemes.

关键词： Finite element methods Programmable control Adaptive control Feedback control

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Fundamental Factors Governing Stabilization of Janus 2D-Bulk Heterostructures with Machine Learning

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ACS Applied Materials and Interfaces 2025年 2025 May 15页

作者： Gorelik, Rachel Boland, Tara M. Singh, Arunima K. School for Engineering of Matter Transport and Energy Arizona State University Tempe 85281 AZ United States Computational Atomic-Scale Materials Design (CAMD) Technical University of Denmark Kgs. Lyngby DK-2800 Denmark Department of Physics Arizona State University Tempe 85281 AZ United States

The more than 6000 2D materials predicted thus far provide a huge combinatorial space for forming functional heterostructures with bulk materials, with potential applications in nanoelectronics, sensing, and energy conversion. In this work, we investigate nearly 1000 heterostructures, the largest number of heterostructures thus far, of 2D Janus and bulk materials’ surfaces using ab initio simulations and machine learning (ML) to deduce the structure-property relationships of the complex interfaces in such heterostructures. We first perform van der Waals-corrected density functional theory simulations using a high-throughput computational framework on 51 Janus 2D materials and 19 metallic, cubic phase, elemental bulk materials that exhibit low lattice mismatches and low coincident site lattices. The formation energies of the resultant 1147 Janus 2D-bulk heterostructures were analyzed, and 828 were found to be thermodynamically stable. ML models were trained on the computed data, and we found that they could predict the binding energy and z-separation of 2D-bulk heterostructures with root mean squared errors (RMSEs) of 0.05 eV/atom and 0.14 Å, respectively. The feature importance of the models reveals that the properties of the bulk materials dominate the heterostructures’ energies and interfacial structures heavily. These findings are in line with experimentally observed behavior of several well-known 2D materials-bulk systems. The data used within this paper are freely available in the Ab Initio 2D-Bulk Heterostructure Database (aiHD). The fundamental insights into 2D-bulk heterostructures and the predictive ML models developed in this work could accelerate the application of thousands of 2D-bulk heterostructures, thus stimulating research within a wide range of electronic, quantum computing, sensing, and energy applications. © 2025 American Chemical Society.

关键词： database density functional theory heterostructure Janus machine learning two-dimensional materials

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Accuracy versus cost for three efficient finite-element solvers

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IEEE TRANSACTIONS ON MAGNETICS 1996年第3期32卷 1385-1388页

作者： Villeneuve, D Webb, JP Computational Analysis and Design Laboratory Electrical Engineering Department McGill University Montreal QUE Canada

Three efficient finite-element schemes are compared for Poisson problems on triangular meshes: (1) uniform subdivision of first order triangles and the incomplete-Choleski conjugate gradient method;(2) uniform subdivision of first-order triangles and a multilevel-preconditioned conjugate gradient method;and (3) uniform increase of polynomial older and diagonally-preconditioned conjugate gradients, Errors in the computed energy, and computational costs, are obtained for a square, air-filled coaxial cable;a linear, curl ent-driven magnetostatic problem;and a microstrip transmission line. Increasing the polynomial order is by far the best approach, i.e. gives the best accuracy for a given cost.

关键词： Costs Finite element methods Gradient methods Polynomials computational efficiency Coaxial cables Magnetostatics Microstrip Transmission lines

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