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Conference on Lasers and Electro-Optics (CLEO)

作者： Nicholas A. Nobile Chuanyu Lian Hongyi Sun Yi-Siou Huang Brian Mills Cosmin Constantin Popescu Dennis Callahan Juejun Hu Carlos A. Ríos Ocampo Nathan Youngblood Electrical & Computer Engineering Department University of Pittsburgh Pittsburgh PA USA Department of Materials Science & Engineering University of Maryland College Park MD USA Institute for Research in Electronics and Applied Physics University of Maryland College Park MD USA Department of Materials Science & Engineering Massachusetts Institute of Technology Cambridge MA USA Draper Scholar Program The Charles Stark Draper Laboratory Inc Cambridge MA USA The Charles Stark Draper Laboratory Inc Cambridge MA USA

Sb 2 Se 3 is used to switch between broadband transparency and enhanced index contrast in two device types leveraging Bragg gratings for tunable stop-and pass-band functionalities. Experimental results highlight fabr... 详细信息

ISBN: (纸本)9798350369311

关键词： Bragg gratings Waveguide transitions Phase change materials Optical filters Optical switches Refractive index Fabry-Perot Indexes Passband Optical waveguides

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Lattice distortion enabling enhanced strength and plasticity in high entropy intermetallic alloy

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Nature Communications 2024年第1期15卷 6782页

作者： Wang, H. Yang, P.Y. Zhao, W.J. Ma, S.H. Hou, J.H. He, Q.F. Wu, C.L. Chen, H.A. Wang, Q. Cheng, Q. Guo, B.S. Qiao, J.C. Lu, W.J. Zhao, S.J. Xu, X.D. Liu, C.T. Liu, Y. Pao, C.W. Yang, Y. Department of Mechanical Engineering City University of Hong Kong Tat Chee Avenue Kowloon Tong Research Center for Applied Sciences Academia Sinica State Key Laboratory of Powder Metallurgy Central South University Department of Mechanical and Energy Engineering Southern University of Science and Technology Institute of Materials Modification and Modeling School of Materials Science and Engineering Shanghai Jiao Tong University Department of Materials and Mineral Resources Engineering National Taipei University of Technology Laboratory for Microstructures Institute of Materials Shanghai University Centre for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Institute of Advanced Wear & amp Corrosion Resistant and Functional Materials Jinan University School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Department of Materials Science and Engineering City University of Hong Kong Tat Chee Avenue Kowloon Tong

Intermetallic alloys have traditionally been characterized by their inherent brittleness due to their lack of sufficient slip systems and absence of strain hardening. However, here we developed a single-phase B2 high-entropy intermetallic alloy that is both strong and plastic. Unlike conventional intermetallics, this high-entropy alloy features a highly distorted crystalline lattice with complex chemical order, leading to multiple slip systems and high flow stress. In addition, the alloy exhibits a dynamic hardening mechanism triggered by dislocation gliding that preserves its strength across a wide range of temperatures. As a result, this high-entropy intermetallic circumvents precipitous thermal softening, with extensive plastic flows even at high homologous temperatures, outperforming a variety of both body-centered cubic and B2 alloys. These findings reveal a promising direction for the development of intermetallic alloys with broad engineering applications. © The Author(s) 2024.

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NOMAD: Nonlinear Manifold Decoders for Operator Learning

arXiv

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arXiv 2022年

作者： Seidman, Jacob H. Kissas, Georgios Perdikaris, Paris Pappas, George J. Graduate Program in Applied Mathematics and Computational Science University of Pennsylvania United States Department of Mechanical Engineering and Applied Mechanics University of Pennsylvania United States Department of Electrical and Systems Engineering University of Pennsylvania United States

Supervised learning in function spaces is an emerging area of machine learning research with applications to the prediction of complex physical systems such as fluid flows, solid mechanics, and climate modeling. By directly learning maps (operators) between infinite dimensional function spaces, these models are able to learn discretization invariant representations of target functions. A common approach is to represent such target functions as linear combinations of basis elements learned from data. However, there are simple scenarios where, even though the target functions form a low dimensional submanifold, a very large number of basis elements is needed for an accurate linear representation. Here we present NOMAD, a novel operator learning framework with a nonlinear decoder map capable of learning finite dimensional representations of nonlinear submanifolds in function spaces. We show this method is able to accurately learn low dimensional representations of solution manifolds to partial differential equations while outperforming linear models of larger size. Additionally, we compare to state-of-the-art operator learning methods on a complex fluid dynamics benchmark and achieve competitive performance with a significantly smaller model size and training cost. © 2022, CC BY-NC-SA.

关键词： Benchmarking

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The thin lens equation in elasticity: imaging with gradient index phononic crystals

arXiv

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arXiv 2024年

作者： Beoletto, P.H. Nistri, F. Gliozzi, A.S. Pugno, N.M. Bosia, F. Department of Applied Science and Technology Politecnico di Torino C.so Duca degli Abruzzi Torino24 - 10129 Italy Laboratory for Bio-inspired Bionic Nano Meta Materials and Mechanics Department of Civil Environmental and Mechanical Engineering University of Trento Trento38123 Italy School of Engineering and Materials Science Queen Mary University of London Mile End Road LondonE1 4NS United Kingdom

Many works in elasticity have exploited the concept of gradient index (GRIN) lenses, borrowed from optics, for wave focusing and control. These effects are particularly attractive for cloaking, absorption or energy harvesting applications. Despite their potential, current lens designs suffer from limitations, mainly related to the difficulty in imaging point-like sources. Here, we exploit an alternative GRIN lens design, which enables a one-to-one correspondence between input and output phase, and allows to determine the focal length using the well-known thin lens equation, effectively establishing the elastic equivalent of the convex lens in optics. This is demonstrated analytically, obtaining a bijective relation between the location of a point-like source and its image, and the results are confirmed numerically and experimentally in an aluminium plate, where the lens is realized by introducing rows of circular cavities of variable diameters. Moreover, a proof-of-concept experiment demonstrates the possibility to image sources of flexural waves at the centimetre scale with subwavelength resolution. This research can extend applications of elastic GRIN lenses to new fields such as imaging and non-destructive testing, where the location of defects can be identified by focusing the scattered field. Multiple sources can be imaged simultaneously, and the combined effect of multiple lenses can also be used to design more complex systems, opening new possibilities in the technological exploitation of elastic wave manipulation. © 2024, CC BY-NC-ND.

关键词： Gradient index optics

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Impact of Quantum Well Thickness on Efficiency Loss in InGaN/GaN LEDs: Challenges for Thin-Well Designs

arXiv

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arXiv 2025年

作者： Li, Xuefeng Pant, Nick Rahman, Sheikh Ifatur Armitage, Rob Rajan, Siddharth Kioupakis, Emmanouil Feezell, Daniel University of New Mexico AlbuquerqueNM87106 United States Department of Materials Science & Engineering University of Michigan Ann ArborMI48109 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Electrical and Computer Engineering The Ohio State University ColumbusOH43210 United States Lumileds LLC San JoseCA95131 United States Department of Materials Science and Engineering The Ohio State University ColumbusOH43210 United States

We investigate the impact of quantum well (QW) thickness on efficiency loss in c-plane InGaN/GaN LEDs using a small-signal electroluminescence (SSEL) technique. Multiple mechanisms related to efficiency loss are independently examined, including injection efficiency, carrier density vs. current density relationship, phase space filling (PSF), quantum confined stark effect (QCSE), and Coulomb enhancement. An optimal QW thickness of around 2.7 nm in these InGaN/GaN LEDs was determined for quantum wells having constant In composition. Despite better control of deep-level defects and lower carrier density at a given current density, LEDs with thin QWs still suffer from an imbalance of enhancement effects on the radiative and intrinsic Auger-Meitner recombination coefficients. The imbalance of enhancement effects results in a decline in internal quantum efficiency (IQE) and radiative efficiency with decreasing QW thickness at low current density in LEDs with QW thicknesses below 2.7 nm. We also investigate how LED modulation bandwidth varies with quantum well thickness, identifying the key trends and their implications for device performance. Copyright © 2025, The Authors. All rights reserved.

关键词： Semiconductor quantum wells

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Ronchigram Simulation and Aberration Correction Training Using ***

引用

Microscopy Today 2022年第5期30卷 40-43页

作者： Sung, Suk Hyun Schnitzer, Noah Millsaps, William Kourkoutis, Lena F Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann Arbor MI 48109 Department of Materials Science and Engineering Cornell University Ithaca NY 14853 Engineering Physics Program University of Michigan Ann Arbor MI 48109 School of Applied and Engineering Physics Cornell University Ithaca NY 14853 Kavli Institute at Cornell for Nanoscale Science Cornell University Ithaca NY 14853

This article introduces a training simulator for electron beam alignment using Ronchigrams. The interactive web application,***, is an advanced educational tool aimed at making scanning transmission electron microscopy (STEM) more accessible and open. For experienced microscopists, the tool offers on-hand quantification of simulated Ronchigrams and their resolution limits.

关键词： Ronchigram scanning transmission electron microscopy aberration correction image simulation software

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Tunable topologically protected waveguiding in auxetic nonlinear metamaterials

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Physical Review applied 2024年第3期21卷 034024-034024页

作者： M. Morvaridi F. Bosia M. Brun V.F. Dal Poggetto A.S. Gliozzi M. Miniaci C. Croënne N.M. Pugno G. Carta Department of Applied Science and Technology Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy Department of Mechanical Chemical and Materials Engineering University of Cagliari Piazza d’Armi 09123 Cagliari Italy Laboratory for Bioinspired Bionic Nano Meta Materials and Mechanics Department of Civil Environmental and Mechanical Engineering University of Trento Trento 38123 Italy Univ. Lille CNRS Centrale Lille Junia Univ. Polytechnique Hauts-de-France UMR 8520 - IEMN - Institut d’Electronique de Microélectronique et de Nanotechnologie F-59000 Lille France School of Engineering and Materials Science Queen Mary University of London London E1 4NS UK

In this paper, we discuss the possibility of achieving tunable topologically protected edge modes through the application of uniaxial prestrain in an auxetic metamaterial. The proposed structure consists of a thin slab with oriented cuts in a hexagonal lattice, where topologically protected band gaps are opened by introducing a controlled variation in selected cut lengths. Numerical simulations demonstrate the existence of topologically protected and scatter-free wave propagation in the structure at the interface between two subdomains with modified cells, in distinct frequency ranges. For the metamaterial considered in this study, this happens only in the presence of auxeticity. In addition, exploiting geometrical nonlinearity, the application of a uniaxial prestrain can be used to close the band gaps or to modify their frequency range, i.e., to weaken the localization effects or to shift the frequency at which they occur. The spatial and temporal variation of the applied strain field can thus be used for the dynamic tuning of metamaterial topological waveguiding properties, with applications in mechanical devices for logic operations and computation.

关键词： Acoustic phonons Elasticity Poisson ratio Strain Acoustic metamaterials Auxetic materials Mechanical metamaterials Finite-element method

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Dependence of Mesoscale Structure of Drawn High-Carbon Steel Wire on Wire Diameter 13th

Dependence of Mesoscale Structure of Drawn High-Carbon Steel...

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13th International Conference on the Technology of Plasticity, ICTP 2021

作者： Gondo, Shiori Tanemura, Rena Mitsui, Ryuki Kajino, Satoshi Asakawa, Motoo Takemoto, Kosuke Tashima, Kenichi Suzuki, Shinsuke 1-2-1 Namiki Tsukuba Ibaraki305-8564 Japan Department of Applied Mechanics Graduate School of Fundamental Science and Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Department of Applied Mechanics Graduate School of Fundamental Science and Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Department of Applied Mechanics and Aerospace Engineering School of Fundamental Science and Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Department of Applied Mechanics and Aerospace Engineering Faculty of Science and Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Factory-Automation Electronics Inc 1-6-14 Higashi-Nakajima Higashi-Yodogawa Osaka Osaka533-0033 Japan Department of Materials Science Faculty of Science and Engineering Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Kagami Memorial Research Institute of Materials Science and Technology Waseda University 2-8-26 Nishi-Waseda Shinjuku Tokyo169-0051 Japan

ISBN: (纸本)9783030753801

This study aims to clarify the transition of mesoscale structure of a drawn wire versus drawing strain. High-carbon steel wires 0.276, 0.444, and 0.936 mm in diameter were drawn until wires could be drawn without rupture. Two results were obtained from a crystal orientation analysis of the electron backscatter diffraction pattern. First, the mesoscale structure in the wire consisted only of a subprimary fiber texture {100}-{111} at the drawing limit, that is the largest drawing strain when the wire could be drawn without rupture. Second, it is predicted that the transition of the mesoscale structure versus the drawing strain will occur as follows regardless of the initial wire diameter: In the beginning of wire drawing, the wire will have only a primary fiber texture {100}-{111}. After a slight increase in the drawing strain, the wire will have the primary fiber texture at its outer side and a secondary fiber texture {111}-{110} at the inner side. After a further increase in the drawing strain, the wire will have a subprimary fiber texture at the outer side and a secondary fiber texture at the inner side. Moreover, increase in the drawing strain, the wire will have only a subprimary fiber texture. © 2021, The Minerals, Metals & materials Society.

关键词： Crystal orientation

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Optimization of lowpass filtered and amplified PRBS phase modulation for SBS mitigation 8

Optimization of lowpass filtered and amplified PRBS phase mo...

引用

8th Symposium on Novel Photoelectronic Detection Technology and Applications

作者： Li, Binglin Yang, Yifeng Liu, Meizhong Wang, Hanbin Gao, Heng Xian, Yuqiao He, Bing Zhou, Jun Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai201800 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China Department of Physics Harbin Institute of Technology Harbin150001 China

ISBN: (数字)9781510653122

ISBN: (纸本)9781510653115

In this work, we investigate the SBS mitigation of the pseudo random bit sequences (PRBS) modulation analytically and numerically. The lightwave is phase modulated by a Butterworth lowpass filtered and amplified PRBS signal, and the SBS suppressing capability versus the parameters such as the filter order, the filter cutoff frequency, the modulation depth, and the pattern length are illustrated. Therefore, we redefine the modulation depth by normalized RMS voltage to integrate binary sequences modulation signal and multi-value sequences modulation signal. On this basis, we demonstrate the impact of pattern length, modulation depth and modulation cutting rate on SBS mitigation and found the corresponding optimal component of n=9, 22.72 dBm and 0.54. On this situation, contrast to the unfiltered PRBS phase modulation scheme, a 17.7% enhancement of normalized SBS threshold can be obtained by using normalized power in the barrel to estimates the linewidth. This work may provide a new idea for SBS mitigation by lowpass filtered PRBS phase modulation in narrow linewidth fiber amplifiers. © 2022 SPIE

关键词： Binary sequences

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Challenges for and Pathways toward Li-MetalBased All-Solid-State Batteries

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ACS ENERGY LETTERS 2021年第4期6卷 1399-1404页

作者： Albertus, Paul Anandan, Venkataramani Ban, Chunmei Balsara, Nitash Belharouak, Ilias Buettner-Garrett, Josh Chen, Zonghai Daniel, Claus Doeff, Marca Dudney, Nancy J. Dunn, Bruce Harris, Stephen J. Herle, Subramanya Herbert, Eric Kalnaus, Sergiy Libera, Joesph A. Lu, Dongping Martin, Steve McCloskey, Bryan D. McDowell, Matthew T. Meng, Y. Shirley Nanda, Jagjit Sakamoto, Jeff Self, Ethan C. Tepavcevic, Sanja Wachsman, Eric Wang, Chunsheng Westover, Andrew S. Xiao, Jie Yersak, Thomas Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 United States Ford Motor Company Dearborn Michigan 48121 United States Mechanical Engineering Department University of Colorado Boulder Colorado 80309 United States Department of Chemical and Biomolecular Engineering and Lawrence Berkeley National Laboratory Materials Sciences Division University of California Berkeley California 94720 United States Energy and Transportation Science Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 United States Solid Power Inc. Louisville Colorado 80027 United States Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Argonne Illinois 60439 United States Lawrence Berkeley National Laboratory Energy Storage and Distributed Resources Division University of California Berkeley California 94720 United States Department of Materials Science and Engineering University of California Los Angeles California 90095 United States Applied Materials Inc. 3225 Oakmead Village Drive B12_2F6 Santa Clara California 95054 United States Department of Materials Science and Engineering Michigan Technological University Houghton Michigan 49931 United States Energy and Environmental Directorate Pacific Northwest National Laboratory Richland Washington 99352 United States Department of Materials Science & Engineering Iowa State University of Science & Technology Ames Iowa 50011 United States Woodruff School of Mechanical Engineering and School of Materials Science and Engineering Georgia Institute of Technology Atlanta Georgia 30332 United States Department of NanoEngineering and Materials Science and Engineering Program University of California San Diego La Jolla California 92093 United States Department of Materials Science and Engineering and Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 United States Chemical and Materials Systems Laborat

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