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Grain Boundary Segregation Models for High-Entropy Alloys: Theoretical Formulation and Derived Analytical Expressions to Elucidate High-Entropy Grain Boundaries

arXiv

引用

arXiv 2024年

作者： Luo, Jian Department of NanoEngineering University of California La Jolla San DiegoCA92093 United States Program in Materials Science and Engineering University of California La Jolla San DiegoCA92093 United States

Grain boundary (GB) segregation models are derived for multi-principal element and high-entropy alloys (MPEAs and HEAs). Differing from classical models where one component is taken as solvent and others are considered solutes, these models are referenced to the bulk composition to enable improved treatments of MPEAs and HEAs with no principal components. An ideal solution model is first formulated and solved to obtain analytical expressions that predict GB segregation and GB energy in MPEAs and HEAs. A regular solution model is further derived. The GB composition calculated using the simple analytical expression derived in this study and data from the materials Project agree well with a prior sphosipcated atomistic simulation for NbMoTaW. The simplicity of the derived analytical expressions makes them useful for not only conveniently predicting GB segregation trends in HEAs, but also analyzing nascent interfacial phenomena in composionally complex GBs. As an application example, the derived models are used to further formulate a set of useful equations to elucidate an emergent concept of high-entropy grain boundaries (HEGBs). © 2024, CC BY.

关键词： Entropy

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Reducing anisotropy of rhombohedral Bi-rich phase for high-performance Ag-alloyed Sn–Bi low-temperature solders

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Journal of materials Research and Technology 2024年 30卷 16-24页

作者： Yang, Chih-han Liu, Yu-chen Nishikawa, Hiroshi Lin, Shih-kang Department of Materials Science and Engineering National Cheng Kung University Tainan70101 Taiwan Joining and Welding Research Institute Osaka University 11-1 Mihogaoka Ibaraki Osaka567-0047 Japan Research Center National Cheng Kung University Tainan70101 Taiwan Program on Smart and Sustainable Manufacturing Academy of Innovative Semiconductor and Sustainable Manufacturing National Cheng Kung University Tainan70101 Taiwan Core Facility Center National Cheng Kung University Tainan70101 Taiwan

The rhombohedral structure is with anisotropic properties, leading to brittle mechanical properties. However, it is one of the major constituent phases, the (Bi) phase, in the Sn–Bi-based low-temperature solders, which is demanding in the electronic industry for reducing the soldering temperature and alleviating the warpage in high-density fine-pitch electronic packaging. Herein, we proposed a high-performance Ag-alloyed Sn–Bi (SBA) low-temperature solder by reducing the fraction and, more importantly, the anisotropy of the (Bi) phase. We found that the (Bi) phase exhibited considerable solubility for Ag and Sn, even after thermal aging, without any nanoprecipitates as confirmed with both CALPHAD-type thermodynamic modeling and high-resolution TEM. The solution effects of Ag and Sn in the (Bi) phase is elaborated based on in situ nano-indentation, EPMA compositional analyses, EBSD characterizations, and ab initio calculations. The presence of Ag and Sn in the (Bi) phases resulted in both solid solution hardening and softening effects, depending on the Schmid factor of the grain. As a result, in (Bi) polycrystals, alloying could effectively mitigate the anisotropic mechanical properties of the (Bi) phase and facilitated a more uniform dispersion of forces exerted among (Bi) grains in all orientations. Consequently, the designed SBA solder exhibited superior mechanical properties, e.g., an ultimate tensile strength (UTS) of 55 MPa, elongation of 46%, and toughness of 20.6 × 106 J/m3 at a strain rate of 0.0005 s−1. This understanding opens the door for enhanced rhombohedral phase in alloy design for various applications. © 2024 The Authors

关键词： Anisotropy

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Comparison of Coherent and Incoherent Donut Beams for Deep Tissue STED Microscopy

Comparison of Coherent and Incoherent Donut Beams for Deep T...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Thariq Shanavas Robert R. McLeod Mark E. Siemens Juliet T. Gopinath Department of Physics University of Colorado Boulder CO USA Department of Electrical Computer and Energy Engineering University of Colorado Boulder CO USA Department of Physics University of Denver Denver CO Materials Science Engineering Program University of Colorado Boulder CO USA

We numerically compare the null quality for STED microscopy generated by Laguerre-Gaussian beams with orbital angular momentum and donut beams generated by incoherent addition of orthogonal Hermite Gaussian beams when... 详细信息

ISBN: (纸本)9781957171258

关键词： Biological imaging Gaussian beams Microscopy Spatial light modulators Spiral phase Step index fibers

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Optical Imaging of Flavor Order in Flat Band Graphene

arXiv

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arXiv 2024年

作者： Xie, Tian Wolf, Tobias M. Xu, Siyuan Cui, Zhiyuan Xiong, Richen Ou, Yunbo Hays, Patrick Holleis, Ludwig F. Guo, Yi Sheekey, Owen I. Patterson, Caitlin Arp, Trevor Watanabe, Kenji Taniguchi, Takashi Tongay, Seth Ariel Young, Andrea F. MacDonald, Allan H. Jin, Chenhao Department of Physics University of California at Santa Barbara Santa BarbaraCA93116 United States Department of Physics University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program School of Engineering for Matter Transport and Energy Arizona State University TempeAZ85287 United States Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan

Spin- and valley flavor polarization plays a central role in the many-body physics of flat band graphene1–21, with fermi surface reconstructions—often accompanied by quantized anomalous Hall1–8 and superconducting state9–14—observed in a variety of experimental systems. Here we describe an optical technique that sensitively and selectively detects flavor textures via the exciton response of a proximal transition metal dichalcogenide layer. Through a systematic study of rhombohedral and rotationally faulted graphene bilayers and trilayers, we show that when the semiconducting dichalcogenide is in direct contact with the graphene, the exciton response is most sensitive to the large momentum rearrangement of the Fermi surface, providing information that is distinct from and complementary to electrical compressibility measurements. The wide-field imaging capability of optical probes allows us to obtain spatial maps of flavor orders with high throughput, and with broad temperature and device compatibility. Our work paves the way for optical probing and imaging of flavor orders in flat band graphene systems. Copyright © 2024, The Authors. All rights reserved.

关键词： Graphene

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Packing fraction related transport in disordered quantum dot arrays

arXiv

引用

arXiv 2024年

作者： Eshraghi, K. Natani, S. Bandaru, P. Program in Materials Science University of California La Jolla San DiegoCA92093 United States Department of Mechanical Engineering University of California La Jolla San DiegoCA92093 United States

Models to describe electrical conduction in quantum dot (QD) constituted films often overlook the effects of geometric disorder. We address related issues by examining the influence of the QD packing fraction (PF) on the charge transport and transmission in QD arrays. Using transfer matrix based algorithms and Monte Carlo simulations, we quantify the transmission across disordered QD assemblies. Our results indicate a critical packing fraction (PFc) of ∼ 0.64, marking a transition from a non-conducting to a conducting state, aligning well with experimental observations and analytical predictions. This study enhances the understanding of transport in QD arrays, with implications for designing efficient electronic devices based on disordered nanoscale systems. © 2024, CC BY-NC-SA.

关键词： Semiconductor quantum dots

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Achieving Near-Intrinsic Exciton Linewidth at Room Temperature in Monolayer WS2 Coupled with a Mie Resonator

Achieving Near-Intrinsic Exciton Linewidth at Room Temperatu...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Jie Fang Kan Yao Yuebing Zheng Materials Science & Engineering Program and Texas Materials Institute The University of Texas at Austin Austin TX USA Walker Department of Mechanical Engineering The University of Texas at Austin Austin TX USA

Strong multiparticle interactions at room temperature (RT) lead to broadened homogeneous exciton linewidths in 2D semiconductors, degrading the quality of excitonic mode and emission. By coupling a Mie resonator with ... 详细信息

ISBN: (数字)9781957171050

ISBN: (纸本)9781665466660

关键词： Couplings Laser theory Excitons Semiconductor lasers Kelvin Lasers and electrooptics Laser modes

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Real-time temperature correction for magnetoresistive biosensors integrated with temperature modulator

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Biosensors and Bioelectronics: X 2023年 14卷 100356页

作者： Kim, Songeun Wang, Shan X. Lee, Jung-Rok Division of Mechanical and Biomedical Engineering Ewha Womans University Seoul03760 Korea Republic of Graduate Program in Smart Factory Ewha Womans University Seoul03760 Korea Republic of Department of Materials Science and Engineering Stanford University StanfordCA93405 United States Department of Electrical Engineering Stanford University StanfordCA93405 United States

Magnetoresistance-based biosensors utilize changes in electrical resistance upon varying magnetic fields to measure biological molecules or events involved with magnetic tags. However, electrical resistance fluctuates with temperature. To decouple unwanted temperature-dependent signals from the signal of interest, various methods have been proposed to correct signals from magnetoresistance-based biosensors. Yet, there is still a need for a temperature correction method capable of instantaneously correcting signals from all sensors in an array, as multiple biomarkers need to be detected simultaneously with a group of sensors in a central laboratory or point-of-care setting. Here we report a giant magnetoresistive biosensor system that enables real-time temperature correction for individual sensors using temperature correction coefficients obtained through a temperature sweep generated by an integrated temperature modulator. The algorithm with individual temperature correction coefficients obviously outperformed that using the average temperature correction coefficient. Further, temperature regulation did not eliminate temperature-dependent signals completely. To demonstrate that the method can be used in biomedical applications where large temperature variations are involved, binding kinetics experiments and melting curve analysis were conducted with the temperature correction method. The method successfully removed all temperature-dependent artifacts and thus produced more precise kinetic parameters and melting temperatures of DNA hybrids. © 2023 The Authors

关键词： Kinetics

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Investigation of Sm Addition on Microstructural and Optical Properties of CoFe Thin Films

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materials 2023年第15期16卷 5380-5380页

作者： Liu, Wen-Jen Chang, Yung-Huang Chiang, Chia-Chin Lai, Jian-Xin Chen, Yuan-Tsung Chen, Hsiung-Liang Lin, Shih-Hung Department of Materials Science and Engineering I-Shou University Kaohsiung840 Taiwan Bachelor Program in Industrial Technology National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou640301 Taiwan Department of Mechanical Engineering National Kaohsiung University of Science and Technology Kaohsiung City80778 Taiwan Graduate School of Materials Science National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou640301 Taiwan Department of Electronic Engineering National Yunlin University of Science and Technology 123 University Road Section 3 Yunlin Douliou640301 Taiwan

CoFe-based alloys and rare earth (RE) elements are among the most studied materials in applying magnetic devices to improve soft magnetic characteristics. A series of Co40Fe40Sm20 films are deposited on a glass substrate via the sputtering technique, followed by an annealing process to investigate their effect on microstructural and optical properties of Co40Fe40Sm20 films. In this study, the increase in the thickness of Co40Fe40Sm20 films and annealing temperatures resulted in a smoother surface morphology. The 40 nm Co40Fe40Sm20 films annealed 300 °C are expected to have good wear resistance and adhesive properties due to their high values of H/E ratio and surface energy. Optical transparency also increased due to the smoother surface of the Co40Fe40Sm20 films. © 2023 by the authors.

关键词： Iron alloys

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Detection of toxic chemicals in hand sanitizers using near-infrared spectroscopy

Detection of toxic chemicals in hand sanitizers using near-i...

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Applied Industrial Spectroscopy, AIS 2021 - Part of Optical Sensors and Sensing Congress 2021

作者： Chowdhury, Aminur Rashid Burney, Umar Hutter, Dan Lee, Tse-Ang Hutter, Tanya Department of Mechanical Engineering University of Texas at Austin AustinTX United States Materials Science and Engineering Program Texas Materials Institute University of Texas at Austin AustinTX United States University of Texas at Austin AustinTX United States

Many alcohol-based hand sanitizer products contain toxic ethanol substitutes. In this work, we demonstrate the application of near-infrared spectroscopy for the detection of methanol and 1-propanol in hand sanitizer u... 详细信息

ISBN: (纸本)9781557528209

关键词： Infrared devices

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Anti-Termite Activity of Azadirachta excelsa Seed Kernel and Its Isolated Compound against Coptotermes curvignathus

Journal of the Korean Wood Science and Technology

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Journal of the Korean Wood science and Technology 2023年第3期51卷 157-172页

作者： Adfa, Morina Wiradimafan, Khafit Pratama, Ricky Febri Sanjaya, Angga Triawan, Deni Agus Yudha S., Salprima Ninomiya, Masayuki Rafi, Mohamad Koketsu, Mamoru Department of Chemistry Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Research Center of Sumatera Natural Product and Functional Materials University of Bengkulu Bengkulu38371 Indonesia Master of Chemistry Study Program Faculty of Mathematics and Natural Sciences University of Bengkulu Bengkulu38371 Indonesia Department of Chemistry and Biomolecular Science Faculty of Engineering Gifu University Gifu5011193 Japan Department of Chemistry Faculty of Mathematics and Natural Sciences IPB University Bogor16128 Indonesia Tropical Biopharmaca Research Center-Institute of Research and Community Services IPB University Bogor16128 Indonesia

Azadirachta excelsa, is a plant belonging to the same genus as Indian neem (Azadirachta indica), and its use as a pesticide is reported by few studies. Despite being a different species, it is expected to have the same biopesticide potential as A. indica. Therefore, this study aims to investigate the anti-termite activity of n-hexane and methanol extracts of A. excelsa seed kernel at various concentrations against Coptotermes curvignathus. The methanol extract demonstrated greater termicidal activity than n-hexane at doses test of 2%, 4%, and 8%. It also showed 100% termite mortality on the third day of administering the 8% dose. According to the gas chromatography with mass spectrometry data, the putative main components of the n-hexane extract were hexadecanoic acid, ethyl ester (18.99%), 9,12-octadecadienoic acid (Z,Z)-(16.31%), and 9-octadecenal (16.23%). In contrast, the principal constituents of methanol extract were patchouli alcohol (28.1%), delta-guaiene (15.15%), and alpha-guaiene (11.93%). Furthermore, limonoids profiling of A. excelsa methanol extract was determined using Ultrahigh-performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry. The number of limonoids identified tentatively was fifteen, such as 6-deacetylnimbin, nimbolidin C, nimbolide, 6-acetylnimbandiol, 6-deacetyl-nimbinene, salannol, 28-deoxonimbolide, gedunin, nimbandiol, epoxyazadiradione, azadirone, 2',3'-dihydrosalannin, marrangin, nimbocinol, and azadirachtin. They were the same as those reported in the seed and leaves of A. indica, but its largest component in A. excelsa was 6-deacetylnimbin. As a result, the presence of these compounds may be responsible for the anti-termite activity of A. excelsa seed kernel extract. Additionally, column chromatography of methanol extract yielded 6-deacetylnimbin, which was found to be antifeedant and termiticide against C. curvignathus. © 2023 The Korean Society of Wood science & Technology.

关键词： Mass spectrometry

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