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Bonding and Failure Mechanisms of Sintered-silver Die-attach on Electroless Nickel (Phosphorus) Surface Finish for Packaging Power Electronics Modules

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IEEE Transactions on Power Electronics 2024年

作者： Wang, Meiyu Zhang, Haobo Hu, Weibo Mei, Yunhui Lu, Guo-Quan Nankai University College of Electronic Information and Optical Engineering Tianjin300350 China Shenzhen research institute of Nankai University Shenzhen518083 China Nankai University Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Tianjin300350 China Tiangong University School of Electrical Engineering Tianjin300387 China The Bradley Department of Electrical and Computer Engineering The Department of Materials Science and Engineering BlacksburgVA24061 United States

The low-temperature silver sintering technology has been increasingly applied for die-attach in power electronics modules. Most reported studies of the technology involved bonding on silver (Ag) or gold (Au) surface finish. Compared to Ag or Au, electroless nickel (phosphorus) or Ni(P) is a cost-effective and widely-used process for surface-finishing module substrates. However, there is a lack of studies on sintered-Ag bonding on the Ni(P) surface. In this study, IGBT devices were bonded using pressureless Ag-sintering on electroless Ni(P)-plated substrates. Micro-morphologies and macro-properties were then characterized before and after three reliability tests including high temperature storage life (HTSL), steady-state temperature-humidity bias life (STHBL), and temperature cycling (TC) tests. The as-sintered joints measured strong adhesion of 39 MPa, resulting from Ag-NiO-Ni chemical bonds across the (111) crystal planes with reduced lattice misfit. The Ag-Ni(P) joints exhibited high reliability under high-temperature and thermo-mechanical stress in the HTSL and TC tests, but performed poorly when exposed to high humidity in the STHBL test. The founding in this study helps understand the physical nature of bonding between sintered-Ag and Ni(P), and its failure mechanisms under the influence of different physical stresses. © 1986-2012 IEEE.

关键词： Bond strength (chemical)

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Why Room Temperature GeSn Lasers Need Carbon

Why Room Temperature GeSn Lasers Need Carbon

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IEEE International Conference on Group IV Photonics

作者： Tuhin Dey Augustus W. Arbogast Qian Meng Shamim Reza Aaron Muhowski Joshua Cooper Rachel S. Goldman Thales Borrely Seth R. Bank Mark A. Wistey Materials Science Engineering and Commercialization Program Texas State University San Marcos Texas USA Department of Physics Texas State University San Marcos Texas USA Department of Electrical and Computer Engineering University of Texas at Austin Austin Texas USA Department of Materials Science and Engineering University of Michigan Ann Arbor MI USA Departments of MSE Physics and EECS University of Michigan Ann Arbor MI USA Department of Physics and MSEC Program Texas State University San Marcos Texas USA

Device models show GeSn lasers are limited by weak electron and photon confinement. Adding carbon offers strong conduction band offsets, freeing SiGeSn layers for separate confinement heterostructures, reducing thresh...

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Periodic phase diagrams in micromagnetics with an eigenvalue solver

arXiv

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arXiv 2024年

作者： Ai, Fangzhou Lin, Zhuonan Duan, Jiawei Lomakin, Vitaliy Department of Electrical and Computer Engineering University of California La Jolla San DiegoCA92093 United States Center for Memory and Recording Research University of California La Jolla San DiegoCA92093 United States Program in Materials Science and Engineering University of California La Jolla San Diego92093 United States

This work introduces an approach to compute periodic phase diagram of micromagnetic systems by solving a periodic linearized Landau-Lifshitz-Gilbert (LLG) equation using an eigenvalue solver with the Finite Element Method formalism. The linear operator in the eigenvalue problem is defined as a function of the periodic phase shift wave vector. The dispersion diagrams are obtained by solving the eigenvalue problem for complex eigen frequencies and corresponding eigen states for a range of prescribed wave vectors. The presented approach incorporates a calculation of the periodic effective field, including the exchange and magnetostatic field components. The approach is general in that it allows handling 3D problems with any 1D, 2D, and 3D periodicities. The ability to calculated periodic diagrams provides insights into the spin wave propagation and localized resonances in complex micromagnetic structures. © 2024, CC BY-NC-ND.

关键词： Spin waves

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Semi-supervised Large-scale Fiber Detection in Material Images with Synthetic Data

arXiv

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arXiv 2023年

作者： Fu, Lan Liu, Zhiyuan Li, Jinlong Simmons, Jeff Yu, Hongkai Wang, Song The Department of Computer Science & Engineering University of South Carolina SC United States The Department of Computer Science University of North Carolina Chapel HillNC United States The School of Information Engineering Chang'an University Xi'An China The Department of Electrical Engineering and Computer Science Cleveland State University OH United States The Materials and Manufacturing Directorate Air Force Research Lab OH United States

Accurate detection of large-scale, elliptical-shape fibers, including their parameters of center, orientation and major/minor axes, on the 2D cross-sectioned image slices is very important for characterizing the underlying cylinder 3D structures in microscopic material images. Detecting fibers in a degraded image poses a challenge to both current fiber detection and ellipse detection methods. This paper proposes a new semi-supervised deep learning method for large-scale elliptical fiber detection with synthetic data, which frees people from heavy data annotations and is robust to various kinds of image degradations. A domain adaptation strategy is utilized to reduce the domain distribution discrepancy between the synthetic data and the real data, and a new Region of Interest (RoI)-ellipse learning and a novel RoI ranking with the symmetry constraint are embedded in the proposed method. Experiments on real microscopic material images demonstrate the effectiveness of the proposed approach in large-scale fiber detection. Copyright © 2023, The Authors. All rights reserved.

关键词： Fibers

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RATE-DEPENDENT TRACTION LAW FOR GLASS FIBER-EPOXY INTERPHASE DEVELOPED USING MOLECULAR SIMULATIONS

RATE-DEPENDENT TRACTION LAW FOR GLASS FIBER-EPOXY INTERPHASE...

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SAMPE 2022 Conference and Exhibition

作者： Chowdhury, Sanjib C. Gillespie, John W. University of Delaware NewarkDE19716 United States Department of Materials Science & Engineering University of Delaware NewarkDE19716 United States Department of Civil & Environmental Engineering University of Delaware NewarkDE19716 United States Department of Mechanical Engineering University of Delaware NewarkDE19716 United States Department of Electrical and Computer Engineering University of Delaware NewarkDE19716 United States

ISBN: (纸本)9781934551417

Impact loading of composites subjects the constituents such as the nanometer scale interphase to high strain loading that can cause fiber-matrix debonding. In multi-scale modeling, interphase debonding is modeled using the interphase traction-separation laws. In this paper, we develop strain rate dependent Mode-I traction law for the glass fiber-epoxy interphase using all-atom molecular dynamics (MD) simulation. The interphase model is prepared considering monolayer glycidoxypropyltrimethoxy silane (GPS) in between the glass surface and epoxy matrix using our developed protocol [Chowdhury et al. Applied Surface science 2021, 542:148738]. Traction laws are developed over a full range of strain rates from quasi-static to super-high strain rate (~ 1e16/s) where a theoretical plateau strength limit is predicted. A stress-relaxation methodology is introduced to construct quasi-static traction-separation responses from high strain rate loading. Simulation results reveal that the interphase traction-separation responses are strain rate dependent. Variations of peak traction and energy with strain rates show a characteristic S-shape pattern in a semi-log plot with a gradual increase in properties up to 1e12/s where a steep transition occurs between 1e13/s to 1e14/s followed by a strain rate independent plateau. MD predicted traction and energy are fitted with mathematical correlations to use them in the finite element-based continuum level micro-mechanics modeling to bridge the length scale for multi-scaling. Copyright 2022. Used by the Society of the Advancement of Material and Process engineering with permission.

关键词： Strain rate

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Analyzing Errors in Controlled Turret System Given Target Location Input from Artificial Intelligence Methods in Automatic Target Recognition

arXiv

引用

arXiv 2024年

作者： Karlson, Matthew Ban, Heng Cole, Daniel G. Abdelhakim, Mai Forsythe, Jennifer Department of Mechanical Engineering and Materials Science University of Pittsburgh PittsburghPA15260 United States Department of Electrical and Computer Engineering University of Pittsburgh PittsburghPA15260 United States DEVCOM Analysis Center Aberdeen Proving GroundMD21005 United States

In this paper, we assess the movement error of a targeting system given target location data from artificial intelligence (AI) methods in automatic target recognition (ATR) systems. Few studies evaluate the impacts on the accuracy in moving a targeting system to an aimpoint provided in this manner. To address this knowledge gap, we assess the performance of a controlled gun turret system given target location from an object detector developed from AI methods. In our assessment, we define a measure of object detector error and examine the correlations with several standard metrics in object detection. We then statistically analyze the object detector error data and turret movement error data acquired from controlled targeting simulations, as well as their aggregate error, to examine the impact on turret movement accuracy. Finally, we study the correlations between additional metrics and the probability of a hit. The results indicate that AI technologies are a significant source of error to targeting systems. Moreover, the results suggest that metrics such as the confidence score, intersection-over-union, average precision and average recall are predictors of accuracy against stationary targets with our system parameters. © 2024, CC BY-NC-ND.

关键词： Object detection

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Exploring the Potential of Tesla Valve for Filtering and Sorting Microscale Active Swimmers: A Computational Study

SSRN

引用

SSRN 2023年

作者： Rogers, Ariel He, Zhiyao Wang, Yong Department of Physics University of Arkansas FayettevilleAR72701 United States Department of Computer Science and Computer Engineering University of Arkansas FayettevilleAR72701 United States Materials Science & Engineering Program University of Arkansas FayettevilleAR72701 United States Cell & Molecular Biology Program University of Arkansas FayettevilleAR72701 United States

An interesting connection between shark spiral intestines and the Tesla valve was proposed recently;however, how Tesla valves interact with active matters and the potential applications of Tesla valves in biology remain largely unexplored. Here, we present a computational study on the potential use of Tesla valves for filtering and sorting microscale active swimmers such as bacteria. We investigated the behavior of microswimmers passing through the Tesla valve at different linear and angular velocities using numerical simulations, and quantified the diodicity of the Tesla valve for active swimmers. Our results demonstrate that the Tesla valve can effectively filter and sort microscale swimmers based on their swimming behavior. The findings of this study suggest that Tesla valves could have potential applications in microscale sorting and chromatography, with significant implications for biomedical and environmental engineering. © 2023, The Authors. All rights reserved.

关键词： Bacteria

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Spectral Extremal Connectivity of Two-State Seizure Brain Waves

arXiv

引用

arXiv 2025年

作者： Talento, Mara Sherlin D. Richards, Jordan Pinto-Orellana, Marco Huser, Raphael Ombao, Hernando C. Statistics Program Computer Electrical and Mathematical Science & Engineering Division King Abdullah University of Science and Technology 23955 - 6900 Saudi Arabia Neuro-AI Laboratory Computer Electrical and Mathematical Science & Engineering Division King Abdullah University of Science and Technology 23955 - 6900 Saudi Arabia School of Mathematics Maxwell Institute for Mathematical Sciences University of Edinburgh EdinburghEH9 3FD United Kingdom Department of Biomedical Engineering University of California Irvine92697 United States

Coherence analysis plays a vital role in the study of functional brain connectivity. However, coherence captures only linear spectral associations, and thus can produce misleading findings when ignoring variations of connectivity in the tails of the distribution. This limitation becomes important when investigating extreme neural events that are characterized by large signal amplitudes. The focus of this paper is to examine connectivity in the tails of the distribution, as this reveals salient information that may be overlooked by standard methods. We develop a novel notion of spectral tail association of periodograms to study connectivity in the network of electroencephalogram (EEG) signals of seizure-prone neonates. We further develop a novel non-stationary extremal dependence model for multivariate time series that captures differences in extremal dependence during different brain phases, namely burst-suppression and non-burst-suppression. One advantage of our proposed approach is its ability to identify tail connectivity at key frequency bands that could be associated with outbursts of energy which may lead to seizures. We discuss these novel scientific findings alongside a comparison of the extremal behavior of brain signals for epileptic and non-epileptic patients. © 2025, CC BY.

关键词： Electroencephalography

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Power-efficient optical bottle-beam traps

Power-efficient optical bottle-beam traps

引用

CLEO: science and Innovations, S and I 2022

作者： Xiao, Yuzhe Yu, Zhaoning Wambold, Raymond A. Mei, Hongyan Hickman, Garrett Goldsmith, Randall H. Saffman, Mark Kats, Mikhail A. Department of Electrical and Computer Engineering University of Wisconsin-Madison MadisonWI53706 United States Department of Physics University of Wisconsin-Madison MadisonWI53706 United States Department of Chemistry University of Wisconsin-Madison MadisonWI53706 United States Materials Science and Engineering University of Wisconsin-Madison MadisonWI53706 United States

We introduced a figure of merit for optical bottle-beam traps, and identified optical bottle-beam traps based on metasurfaces illuminated by a Gaussian beam that are superior in terms of power efficiency compared to e... 详细信息

ISBN: (纸本)9781557528209

关键词： Gaussian beams

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Strain-Balanced AlScN/GaN HEMTs with fT/fMAX of 173/321 GHz

Strain-Balanced AlScN/GaN HEMTs with fT/fMAX of 173/321 GHz

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International Electron Devices Meeting (IEDM)

作者： T. S. Nguyen K. Nomoto W. Zhao C. Savant H. G. Xing D. Jena Department of Materials Science and Engineering Cornell University Ithaca NY USA School of Electrical and Computer Engineering Cornell University Ithaca NY USA School of Applied and Engineering Physics Cornell University Ithaca NY USA Kavli Institute at Cornell for Nanoscale Science Cornell University Ithaca NY USA

ISBN: (数字)9798350365429

ISBN: (纸本)9798350365436

We report the effect of scaling the gate length from 0.8 µm to 40 nm on the performance of novel strain-balanced AlScN/GaN high electron mobility transistors (HEMTs) on SiC substrates. A new strain-balanced heterostructure is introduced where the tensile strain of the AlN interlayer is balanced by the compressive strain in the AlScN barrier layer. MBE regrown source/drain ohmics with ultralow contact resistance of 0.09 Ω·mm allow a low HEMT on resistance of 0.83 Ω·mm. The shortest gate length AlScN/GaN HEMTs exhibit maximum drain currents of 2.8 A/mm, peak transconductance of 0.55 S/mm, and speed characterized by $f_{T}$ / $f_{MAX}$ of 173/321 GHz. The highest $f_{MAX}$ obtained here is ~2X higher than previous AlScN HEMTs.

关键词： Resistance Tensile strain Silicon carbide HEMTs Logic gates MODFETs III-V semiconductor materials Electron devices Transconductance Substrates

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