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Emergence of near-boundary segregation zones in face-centered cubic multiprincipal element alloys

Physical Review materials 2021年第11期5卷 113601-113601页

作者： Megan J. McCarthy Hui Zheng Diran Apelian William J. Bowman Horst Hahn Jian Luo Shyue Ping Ong Xiaoqing Pan Timothy J. Rupert Materials and Manufacturing Technology Program University of California Irvine California 92697 USA Department of NanoEngineering University of California San Diego La Jolla California 92093 USA Department of Materials Science and Engineering University of California Irvine California 92697 USA Institute of Nanotechnology Karlsruhe Institute of Technology 76344 Eggenstein-Leopoldshafen Germany

Grain boundaries have been shown to dramatically influence the behavior of relatively simple materials such as monatomic metals and binary alloys. The increased chemical complexity associated with multiprincipal element alloys is hypothesized to lead to unique grain boundary phenomena. To explore the relationship between grain boundary structure and chemistry in these materials, hybrid molecular dynamics/Monte Carlo simulations of a faceted Σ11 〈110〉 tilt boundary, chosen to sample both high- and low-energy boundary configurations, are performed in face-centered cubic (fcc) CrFeCoNiCu and CrFeCoNi equiatomic alloys. Unexpected enrichment of Fe is discovered in the fcc regions adjacent to the interface and found to be correlated with a structurally distinct region of reduced atomic volume. Comparison with the boundary of the same type in monatomic Cu demonstrates that altered near-boundary regions exist in simpler systems as well, with the chemical complexity of the multiprincipal element alloys highlighting its existence and importance.

关键词： Dopants Grain boundaries Microstructure Interfaces Solid-solid interfaces Molecular dynamics Monte Carlo methods

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Decoding the Roles of Amyloid-β (1-42)’s Key Oligomerization Domains toward Designing Epitope-Specific Aggregation Inhibitors

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JACS Au 2023年第4期3卷 1065-1075页

作者： Im, Dongjoon Kim, Soohyeong Yoon, Gyusub Hyun, Da Gyeong Eom, Yu-Gon Lee, Ye Eun Sohn, Chang Ho Choi, Jeong-Mo Kim, Hugh I. Department of Chemistry Korea University Seoul 02841 South Korea Center for Proteogenome Research Korea University Seoul 02841 South Korea Single Cell Analysis Laboratory Korea University Seoul 02841 South Korea Department of Chemistry Pusan National University Busan 46241 South Korea Center for Nanomedicine Institute for Basic Science (IBS) Seoul 03722 South Korea Graduate Program in Nanobiomedical Engineering Advanced Science Institute Yonsei University Seoul 03722 South Korea Chemistry Institute for Functional Materials Pusan National University Busan 46241 South Korea

Fibrillar amyloid aggregates are the pathological hallmarks of multiple neurodegenerative diseases. The amyloid-β (1-42) protein, in particular, is a major component of senile plaques in the brains of patients with Alzheimer’s disease and a primary target for disease treatment. Determining the essential domains of amyloid-β (1-42) that facilitate its oligomerization is critical for the development of aggregation inhibitors as potential therapeutic agents. In this study, we identified three key hydrophobic sites (¹⁷LVF¹⁹³²IGL³⁴, and ⁴¹IA⁴²) on amyloid-β (1-42) and investigated their involvement in the self-assembly process of the protein. Based on these findings, we designed candidate inhibitor peptides of amyloid-β (1-42) aggregation. Using the designed peptides, we characterized the roles of the three hydrophobic regions during amyloid-β (1-42) fibrillar aggregation and monitored the consequent effects on its aggregation property and structural conversion. Furthermore, we used an amyloid-β (1-42) double point mutant (I41N/A42N) to examine the interactions between the two C-terminal end residues with the two hydrophobic regions and their roles in amyloid self-assembly. Our results indicate that interchain interactions in the central hydrophobic region (¹⁷LVF¹⁹) of amyloid-β (1-42) are important for fibrillar aggregation, and its interaction with other domains is associated with the accessibility of the central hydrophobic region for initiating the oligomerization process. Our study provides mechanistic insights into the self-assembly of amyloid-β (1-42) and highlights key structural domains that facilitate this process. Our results can be further applied toward improving the rational design of candidate amyloid-β (1-42) aggregation inhibitors. © 2023 The Authors. Published by American Chemical Society.

关键词： aggregation conformation inhibitors oligomers peptides and proteins

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Sample Preconcentration Through Airjet-Induced Liquid Phase Enrichment

SSRN

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SSRN 2023年

作者： Wang, Edward Laurent, Louise C. Hall, Drew A. Lo, Yu-Hwa Department of Aerospace and Mechanical Engineering Materials Science and Engineering Program University of California La Jolla San DiegoCA United States Sanford Consortium of Regenerative Medicine United States Department of Electrical and Computer Engineering University of California La Jolla San DiegoCA United States Department of Bioengineering

Sample preparation is essential for nucleic acid assays, affecting their sensitivity and reliability. However, this process often results in a significant loss or dilution of the analyte, which becomes a bottleneck that limits downstream assay performance, particularly for assays that accept a limited input sample volume. To overcome this challenge, we present an evaporative-based sample enrichment method that uses an airjet to concentrate analytes within a small, defined volume by reversing the coffee-ring effect. A small, concentrated sample can then be collected for analysis to increase the initial sample load. The effectiveness of the reported airjet enrichment was quantified using qPCR of λ-DNA, HeLa-S3 RNA, and heat-inactivated SARS-CoV-2 samples. Comparisons between airjet enrichment and conventional evaporative concentration methods demonstrated significant advantages of airjet enrichment, including the ability to concentrate a high percentage of analyte within a 1 µL volume. The enrichment method was then integrated and adapted for various fluid volumes commonly found in nucleic acid sample preparation procedures. Here, airjet enrichment reduced the overall [[EQUATION]] by an average of 9.27 cycles for each analyte, resulting in a 600-fold enrichment from the initial concentration. In addition, to perform selective enrichment and prevent salt-based interference in downstream analysis, PEG was added to reduce the co-enrichment of salt. These studies show how airjet enrichment technology can be easily integrated into existing laboratory protocols with minimal modification and significantly improve the performance of nucleic acid amplification assays. © 2023, The Authors. All rights reserved.

关键词： Biomolecules

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Two-step electronic response to magnetic ordering in a van der Waals ferromagnet

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Physical Review B 2024年第4期109卷 045416-045416页

作者： Han Wu Jian-Xin Zhu Lebing Chen Matthew W. Butcher Ziqin Yue Dongsheng Yuan Yu He Ji Seop Oh Bin Gao Jianwei Huang Shan Wu Cheng Gong Yucheng Guo Sung-Kwan Mo Jonathan Denlinger Donghui Lu Makoto Hashimoto Matthew B. Stone Alexander I. Kolesnikov Songxue Chi Junichiro Kono Andriy H. Nevidomskyy Robert J. Birgeneau Pengcheng Dai Ming Yi Department of Physics and Astronomy and Rice Center for Quantum Materials Rice University Houston Texas 77005 USA Theoretical Division Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Center for Integrated Nanotechnologies Los Alamos National Laboratory Los Alamos New Mexico 87545 USA Department of Physics University of California at Berkeley Berkeley California 94720 USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA National Institute for Materials Science 1-1 Namiki Tsukuba Ibaraki 305-0044 Japan Department of Applied Physics Yale University New Haven Connecticut 06511 USA Department of Electrical and Computer Engineering and Quantum Technology Center University of Maryland College Park Maryland 20742 USA Advanced Light Source Lawrence Berkeley National Laboratory Berkeley California 94720 USA Stanford Synchrotron Radiation Lightsource SLAC National Accelerator Laboratory Menlo Park California 94025 USA Neutron Scattering Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Smalley-Curl Institute Rice University Houston Texas 77005 USA Department of Material Science and Nanoengineering Rice University Houston Texas 77005 USA Department of Materials Science and Engineering University of California Berkeley California 94720 USA

The two-dimensional material Cr2Ge2Te6 is a member of the class of insulating van der Waals (vdW) magnets. Here, using high resolution angle-resolved photoemission spectroscopy in a detailed temperature dependence study, we identify a clear response of the electronic structure to a dimensional crossover in the form of two distinct temperature scales marking onsets of modifications in the electronic structure. Specifically, we observe Te p-orbital-dominated bands to undergo changes at the Curie transition temperature TC while the Cr d-orbital-dominated bands begin evolving at a higher temperature scale. Combined with neutron scattering, density functional theory calculations, and Monte Carlo simulations, we find that the electronic system can be consistently understood to respond sequentially to the distinct temperatures at which in-plane and out-of-plane spin correlations exceed a characteristic length scale. Our findings reveal the sensitivity of the orbital-selective electronic structure for probing the dynamical evolution of local moment correlations in vdW insulating magnets.

关键词： Electronic structure Magnetic order Magnetic phase transitions Van der Waals systems Angle-resolved photoemission spectroscopy

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Subwavelength-Engineered Antislot Photonic Crystals in a Silicon Photonics Foundry for On-chip Communications

Subwavelength-Engineered Antislot Photonic Crystals in a Sil...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Kellen P. Arnold Joshua A. Allen Sami I. Halimi Landen D. Ryder Francis O. Afzal Yusheng Bian Abdelsalam Aboketaf Takako Hirokawa Kevin Dezfulian Michal Rakowski Rod Augur Karen Nummy Sharon M. Weiss Interdisciplinary Materials Science Program Vanderbilt University Nashville TN USA Department of Electrical and Computer Engineering Vanderbilt University Nashville TN USA NASA Goddard Space Flight Center Greenbelt MD US GlobalFoundries Malta NY USA

We report scalable foundry fabrication and characterization of photonic crystal nanobeam waveguides incorporating subwavelength-scale dielectric antislot unit cells. This work enables enhanced light-matter interaction... 详细信息

ISBN: (纸本)9798350369311

关键词： Mach-Zehnder interferometers Optical device fabrication Photonic crystals Waveguide lasers Lasers and electrooptics Electro-optic modulators Silicon photonics Foundries System-on-chip Electro-optical waveguides

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High-Order Nonlinear Electrophoresis in a Nematic Liquid Crystal

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Physical Review Letters 2024年第15期132卷 158102-158102页

作者： Mojtaba Rajabi Taras Turiv Bing-Xiang Li Hend Baza Dmitry Golovaty Oleg D. Lavrentovich Advanced Materials and Liquid Crystal Institute Kent State University Kent Ohio 44242 USA Department of Physics Kent State University Kent Ohio 44242 USA College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology) Nanjing University of Posts and Telecommunications Nanjing 210023 China Department of Mathematics The University of Akron Akron Ohio 44325-4002 USA Materials Science Graduate Program Kent State University Kent Ohio 44242 USA

Electrophoresis is the motion of particles relative to a surrounding fluid driven by a uniform electric field. In conventional electrophoresis, the electrophoretic velocity grows linearly with the applied field. Nonlinear effects with a quadratic speed vs field dependence are gaining research interest since an alternating current field could drive them. Here, we report on the giant nonlinearity of electrophoresis in a nematic liquid crystal in which the speed grows with the fourth and sixth powers of the electric field. The mechanism is attributed to the shear thinning of the nematic environment induced by the moving colloid. The observed giant nonlinear effect dramatically enhances the efficiency of electrophoretic transport.

关键词： Electrophoresis Non-Newtonian fluids Nonlinear dynamics in fluids Colloids Liquid crystals Nematic liquid crystals Optical microscopy Rheology techniques

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Intermetallic Compound Formation and Growth Behavior Between Ruthenium and Tin System

Intermetallic Compound Formation and Growth Behavior Between...

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International Conference on Electronics Packaging (ICEP)

作者： Hsiu-mei Yang Tzu-hsuan Huang Yu-hsuan Lin Min-cian Chen Shih-kang Lin Department of Materials Science and Engineering National Cheng Kung University Tainan Taiwan Program on Semiconductor Packaging and Testing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan Taiwan Taiwan Semiconductor Manufacturing Company Limited Hsinchu Taiwan

ISBN: (数字)9784991191190

ISBN: (纸本)9798331514747

This study investigates the liquid/solid reflow process under a vacuum environment of 1 Pa at reflow temperatures of 300°C for different reaction times. The research finds that at the Sn/Ru interface, during 300°C reflow for 24 hours, the RU 3 Sn 7 intermetallic compound was formed. As the reflow time increases, the IMC thickness increases. This study provides a fundamental understanding of the interfacial reactions between Sn and Ru. The mechanisms of the interfacial reactions and the growth kinetics of the intermetallic compounds (IMC) will be revealed through phase diagrams, thermodynamics, and kinetic analysis.

关键词： Thermodynamics Ruthenium Tin Atoms Kinetic theory Intermetallic Compounds Microstructure Substrates Electronics packaging

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Reduced graphene oxide-manganese ferrite/zinc oxide nanorods coated carbonized cotton fabric for absorption-dominant electromagnetic interference shielding

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Surfaces and Interfaces 2024年 46卷

作者： Gupta, Shivam Tripathy, Anupam Ruturaj Tai, Nyan-Hwa Department of Materials Science and Engineering National Tsing Hua University No. 101 Sec. 2 Guang-Fu Road Hsinchu 300 Taiwan Institute of NanoEngineering and MicroSystems National Tsing Hua University No. 101 Sec. 2 Guang-Fu Road Hsinchu 300 Taiwan

In this interconnected world, safeguarding electronic devices from electromagnetic interference (EMI) is crucial. This study introduces an innovative approach to enhance EMI shielding by synergistically coating cotton fabric with vertically aligned zinc oxide nanorods (ZnO NRs) and reduced graphene oxide-magnetic ferrite nanoparticles (RGO-MF). Vertical ZnO NRs coating is achieved by seeding cotton fabric with ZnO nanoparticles, followed by hydrothermal NR growth. Subsequently, uniform RGO-MF coating is carried out by spraying a solution of graphene oxide-MF nanoparticles onto ZnO NRs coated cotton, followed by thermal annealing to reduce graphene oxide. Our observations reveal that EMI shielding effectiveness increases with RGO loading, while reflection loss decreases due to enhanced cotton fabric conductivity. Careful optimization of RGO-MF on ZnO NRs coated cotton is demonstrated. The incorporation of MF nanoparticles not only improves EMI shielding but also enhances reflection loss, highlighting the shield's absorption-dominant nature. The resulting RGO-MF/ZnO NRs coated cotton exhibits a high total EMI shielding effectiveness of ∼55 dB, reflection loss of 6.8 dB, and an absorption coefficient of 74.5 %, which attribute to the remarkable dielectric properties of ZnO NRs, the exceptional conductivity of RGO sheets, the strong magnetism of MF nanoparticles, and the enhanced core-shell structure of the cotton fabric with these materials. © 2024 Elsevier B.V.

关键词： Electrical properties Electron microscopy EMI shielding Fabric composites Microwave absorption

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Dispersion of cobalt ferrite functionalized graphene nanoplatelets in PLA for EMI shielding applications 36

Dispersion of cobalt ferrite functionalized graphene nanopla...

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36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021

作者： Anurakparadorn, Kanat Taub, Alan Michielssen, Eric Department of Materials Science and Engineering Macromolecular Science and Engineering Program University of Michigan 2300 Hayward St Ann ArborMI48109 United States Department of Mechanical Engineering University of Michigan 2350 Hayward St Ann ArborMI48109 United States Department of Electrical Engineering and Computer Science University of Michigan 1310 Beal Ave Ann ArborMI48109 United States

ISBN: (纸本)9781713837596

The proliferation of wireless technology calls for the development of cost-effective Electromagnetic Interference (EMI) shielding materials that reduce the susceptibility of high-speed electronic circuits to undesired incoming radiation. Ideally, such materials offer protection over wide frequency ranges and are insensitive to the polarization or angle of incidence of the impinging fields. Here, next-generation EMI shielding materials composed of polymer composites with conductive and magnetic fillers are introduced. It is shown that careful control of the concentration and dispersion of the polymers’ conductive and magnetic constituents permits tuning of the composites’ intrinsic electrical and magnetic properties. The resulting EMI shields are lightweight, cheap and offer greater protection than traditional metal gaskets and foams. In this work, cobalt ferrite magnetic nanoparticles (CoFe2O4) decorated on graphene-based material were dispersed in polylactic acid (PLA) matrix for high EM absorption level in X-band (8-12 GHz). The decoration of the magnetic particles was performed on the as-prepared conductive graphene nanoplatelets (GNP) and reduced graphene oxide (rGO). GNP composites exhibited higher DC conductivity, and permittivity than rGO composites. This is attributed to issues associated with the reduction process, including a lack of conductivity due to the insulated oxygen functional groups and the reduction in the lateral size. Compared with rGOs, the lack of out-plane functional groups causes the cobalt ferrite nanoparticles to agglomerate and not cover the entire surface of the GNPs. These morphological differences improve the magnetization and EM absorption of the composite system. The compatibilizer (pyrene-PLA-OH) was added to the composites to enhance dispersion of the GNPs in the polymer matrix which benefits in higher absorption of the shield. The influence of the compatibilizer on parameter, the reflection loss (RL) of the composite were determi

关键词： Cost effectiveness

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Minimizing finite viscosity enhances relative kinetic energy absorption in bistable mechanical metamaterials but only with sufficiently fine discretization: a nonlinear dynamical size effect

arXiv

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arXiv 2024年

作者： Xiu, Haning Fancher, Ryan Frankel, Ian Ziemke, Patrick Fermen-Coker, Müge Begley, Matthew Boechler, Nicholas Department of Mechanical and Aerospace Engineering University of California La Jolla San DiegoCA United States Department of Mechanical Engineering University of California Santa Barbara Santa BarbaraCA United States Materials Department University of California Santa Barbara Santa BarbaraCA United States DEVCOM Army Research Laboratory Aberdeen Proving GroundMD United States Program in Materials Science and Engineering University of California La Jolla San DiegoCA United States

Bistable mechanical metamaterials have shown promise for mitigating the harmful consequences of impact by converting kinetic energy into stored strain energy, offering an alternative and potentially synergistic approach to conventional methods of attenuating energy transmission. In this work, we numerically study the dynamic response of a one-dimensional bistable metamaterial struck by a high speed impactor (where the impactor velocity is commensurate with the sound speed), using the peak kinetic energy experienced at midpoint of the metamaterial compared to that in an otherwise identical linear system as our performance metric. We make five key findings: 1) The bistable material can counter-intuitively perform better (to nearly 103× better than the linear system) as the viscosity decreases (but remains finite), but only when sufficiently fine discretization has been reached (i.e. the system approaches sufficiently close to the continuum limit);2) This discretization threshold is sharp, and depends on the viscosity present;3) The bistable materials can also perform significantly worse than linear systems (for low discretization and viscosity or zero viscosity);4) The dependence on discretization stems from the partition of energy into trains of solitary waves that have pulse lengths proportional to the unit cell size, where, with intersite viscosity, the solitary wave trains induce high velocity gradients and thus enhanced damping compared to linear, and low-unit-cell-number bistable, materials;and 5) When sufficiently fine discretization has been reached at low viscosities, the bistable system outperforms the linear one for a wide range of impactor conditions. The first point is particularly important, as it shows the existence of a nonlinear dynamical "size effect", where, given a protective layer of some thickness and otherwise identical quasi-static mechanical properties and total mass, e.g., a 1 mm thick layer having 200 unit cells of 5 µm thickness is predicte

关键词： Kinetic energy

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