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arXiv 2022年

作者： Sung, Suk Hyun Schnitzer, Noah Millsaps, William Kourkoutis, Lena F. Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering Cornell University IthacaNY14853 United States Engineering Physics Program University of Michigan Ann ArborMI48109 United States School of Applied and Engineering Physics Cornell University IthacaNY14853 United States Kavli Institute Cornell for Nanoscale Science Cornell University IthacaNY14853 United States

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. © 2022, CC BY.

关键词： High resolution transmission electron microscopy

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Mitigating oxygen reduction reaction barriers: An in-depth first-principles exploration of high-entropy alloy as catalysts

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Electrochemistry Communications 2024年 166卷

作者： Chen, Ming-Yi Thanh Thuy Tran, Ngoc Hsu, Wen-Dung Department of Materials Science and Engineering National Cheng Kung University 1 University Road Tainan701 Taiwan Research Center National Cheng Kung University Tainan701 Taiwan Program on Semiconductor Packaging and Testing Academy of Innovative Semiconductor and Sustainable Manufacture National Cheng Kung University Tainan701 Taiwan

This study investigates the effectiveness of high-entropy alloys (HEAs) as catalysts for reducing the energy barrier of the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). Four HEAs—IrPdPtRh, CoCrFeNi, NbMoTaW, and TiZrNbTa—are analyzed as potential catalysts. This superiority arises from the shift in the overall d-band center position towards negative energy in HEAs. The study suggests that an increased standard deviation of atomic valences within HEAs correlates positively with improved ORR efficiency, indicating it as a potential design indicator for cost-effective catalysts. Moreover, predictions of valence variations based on differences in electronegativity between individual elements are proposed. Additionally, the research highlights that additional surface adsorption of Pt on HEAs would further enhance ORR activity. © 2024

关键词： Catalysts

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Graphene-based analog of single-slit electron diffraction

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Physical Review B 2023年第12期108卷 125420-125420页

作者： Dipanjan Saha Dacen Waters Ching-Chen Yeh Swapnil M. Mhatre Ngoc Thanh Mai Tran Heather M. Hill Kenji Watanabe Takashi Taniguchi David B. Newell Matthew Yankowitz Albert F. Rigosi Physical Measurement Laboratory National Institute of Standards and Technology (NIST) Gaithersburg Maryland 20899 USA Intelligence Community Postdoctoral Research Fellowship Program University of Washington Seattle Washington 98195 USA Department of Physics University of Washington Seattle Washington 98195 USA Department of Physics National Taiwan University Taipei 10617 Taiwan Joint Quantum Institute University of Maryland College Park Maryland 20742 USA Research Center for Functional Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan International Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Department of Materials Science and Engineering University of Washington Seattle Washington 98195 USA

In this paper, we report on the experimental demonstration of single-slit diffraction exhibited by electrons propagating in encapsulated graphene with an effective de Broglie wavelength corresponding to their attributes as massless Dirac fermions. Nanometer-scale device designs were implemented to fabricate a single-slit followed by five detector paths. Predictive calculations were also utilized to readily understand the observations reported. These calculations required the modeling of wave propagation in ideal case scenarios of the reported device designs to more accurately describe the observed single-slit phenomenon. This experiment was performed at room temperature and 190 K, where data from the latter highlighted the exaggerated asymmetry between electrons and holes, recently ascribed to slightly different Fermi velocities near the K point. This observation and device concept may be used for building diffraction switches with versatile applicability.

关键词： Interference & diffraction of light Electrons Graphene

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Groundwater-Surface Water Interactions Research: Past Trends and Future Directions

SSRN

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SSRN 2024年

作者： Irvine, Dylan J. Singha, Kamini Kurylyk, Barret L. Briggs, Martin A. Sebastian, Yakub Tait, Douglas R. Helton, Ashley M. Research Institute for the Environment and Livelihoods Faculty of Science and Technology Charles Darwin University CasuarinaNT Australia National Centre for Groundwater Research and Training Bedford ParkSA Australia Hydrologic Science and Engineering Program Colorado School of Mines GoldenCO United States Department of Civil and Resource Engineering Centre for Water Resources Studies Dalhousie University Halifax Canada U.S. Geological Survey Observing Systems Division Hydrologic Remote Sensing Branch StorrsCT United States Faculty of Science and Engineering Southern Cross University Lismore Australia Department of Natural Resources and the Environment The Center for Environmental Sciences and Engineering University of Connecticut StorrsCT United States

Interactions between groundwater and surface water sustain groundwater-dependent ecosystems, provide baseflow to rivers, and regulate river temperature and biogeochemical cycles, amongst many other processes. These interactions occur in freshwater environments including rivers, springs, lakes, and wetlands, and in coastal environments via tidal pumping, submarine groundwater discharge, and seawater intrusion. Here, we use a data-driven approach to explore groundwater-surface water interactions research using 20,275 journal papers published between 1970 and 2023. Analyses show that research into groundwater-surface water interactions is highly multi-disciplinary, with growing contributions from the social and biological sciences. As in the case with many research areas, the number of groundwater-surface water interactions papers is rapidly increasing with over 1200 papers published per year since 2020. Drawing on our data-driven approach and expert knowledge, we synthesise current research trends and identify critical future research directions. Despite the thousands of papers on groundwater-surface water interactions, there are still important processes that are difficult to quantify or predict at meaningful spatial scales to inform management. We see benefits in future groundwater-surface water interactions research focusing on: (1) embracing new technologies including the use of internet-of-things-based sensors and further use of uncrewed vehicles in data capture and remote sensing approaches to inform groundwater-surface water interactions at large scales, (2) capitalising on the increased computational power, availability of physically based models, and machine learning to inform hydrological and biogeochemical processes, and (3) continuing the movement towards multi-disciplinary investigations to better inform the quantification of groundwater-surface water interactions that will enable better management outcomes. © 2024, The Authors. All rights reserved.

关键词： Rivers

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Propolis nanoemulsion extract from celebes stingless bee (Tetragonula biroi) phytochemistry and antibacterial analysis to periodontopathogen bacteria

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Journal of Oral Biology and Craniofacial Research 2025年第3期15卷 576-584页

作者： Amalia, Nadya Rafika Budhy, Theresia Indah Ridwan, Rini Devijanti Rianti, Devi Bramantoro, Taufan Luthfi, Muhammad Ramadhani, Nastiti Faradilla Pramusita, Adya Putranti, Nurul Aisyah Rizki Nugraha, Albertus Putera Situmorang, Putri Cahaya Shariff, Khairul Anuar Nugraha, Alexander Patera Dental Health Science Study Program Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Oral and Maxillofacial Pathology Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Oral Biology Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Dental Material Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Dental Public Health Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Dentomaxillofacial Radiology Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Department of Orthodontic Faculty of Dental Medicine Universitas Airlangga Surabaya Indonesia Faculty of Medicine Universitas Airlangga Surabaya Indonesia Biology Study Program Faculty of Mathematics and Natural Sciences Universitas Sumatera Utara Medan Indonesia School of Materials and Mineral Resources Engineering Engineering Campus Universiti Sains Malaysia Penang Nibong Tebal 14300 Malaysia

Background: Propolis from Sulawesi's stingless bees (Tetragonula biroi) contains antioxidants, more flavonoids than propolis from Apis bees, and the antibacterial ability. Objective: to examine the antibacterial properties of Propolis Nanoemulsion Extract (PNE), which is extracted from the Celebes Stingless Bee (T. biroi), in relation to the periodontopathogen bacteria such as Fusobacterium nucleatum (Fn), Porphyromonas gingivalis (Pg), Aggregatibacter actinomycetemcomitans (Aa), and Provotella intermedia (Pi). This investigation also examines PNE's phytochemistry, particle size analysis (PSA), and zeta potential. Methods: The maceration process with 96 % ethanol was used to create PNE from Celebes stingless bee (T. biroi), which was then subjected to zeta potential measurement and PSA. Phytochemical analysis was used to identify phytochemical constituents in the PNE (T. biroi). Diffusion zone, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) were used to assess antibacterial efficacy against Aa, Pg, Pi, and Fn. Furthermore, the statistical analysis was used to extract the data. Results: Phenols, alkaloids, and flavonoids were identified;however, triterpenoids and saponins were not. Between 151.28 and 182.2 diameter nanometers (***) was the range of the PNE's diameter. At 1.56 % propolis (T. biroi) concentration, the MIC, MBC, and diffusion zone analysis performed better than at 0.76 %, with a significant difference (p:0.01;p < 0.05) to Aa, Pg, Pi, and Fn. Conclusions: The highest antibacterial activity against Aa, Pg, Pi, and Fn as periodontopathogen bacteria is demonstrated by alkaloids, flavonoids, and phenols in PNE from Celebes (T. biroi) at a concentration of 1.56 %. © 2025 The Authors

关键词： Antibacterial Communicable disease Infectious disease Medicine Periodontal disease

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Enhancing oxygen reduction reaction with Pt-decorated Cu@Pd and high-entropy alloy catalysts: Insights from first-principles analysis of Pt arrangement

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Applied Catalysis A: General 2024年 669卷

作者： Chen, Ming-Yi Tran, Ngoc Thanh Thuy Alao, Ahmed Abubakar Hsu, Wen-Dung Department of Materials Science and Engineering National Cheng Kung University 1 University Road Tainan701 Taiwan Research Center National Cheng Kung University Tainan701 Taiwan Program on Semiconductor Packaging and Testing Academy of Innovative semiconductor and Sustainable Manufacture National Cheng Kung University Tainan701 Taiwan

The efficiency of oxygen reduction reaction (ORR) in the proton-exchange membrane fuel cells (PEMFCs) heavily relies on the surface Pt atom arrangement, which can be represented by the Pt-Pt average distance. Here, we employed density functional theory (DFT) to examine the influence of Pt arrangement on the ORR efficiency of Cu@Pd core-shell and high-entropy alloy catalysts. Our DFT calculations reveal that a shorter Pt-Pt average distance on the surface leads to a lower O2 dissociation barrier. Nevertheless, a shorter Pt-Pt average distance is not thermodynamically favored for the Cu@Pt catalyst. Moreover, we discovered a robust correlation between the level of the d-band center of the catalyst and the O2 adsorption energy. To explore the potential of controlling Pt arrangement, we investigated the use of NbMoTaW high-entropy alloy (HEA) substrates. Our findings suggest that HEA substrates provide promising surface chemistry for tuning Pt arrangement and controlling the O2 dissociation barrier. © 2023

关键词： Oxygen

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Determination of Majorana type-phases from the time evolution of lepton numbers

arXiv

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arXiv 2022年

作者： Benoit, Nicholas J. Kawamura, Yuta Hamada, Saki Morozumi, Takuya Shimizu, Yusuke Yamamoto, Kei Graduate School of Science Hiroshima University Higashi-Hiroshima739-8526 Japan Mie Yokkaichi City Japan Higashi-Hiroshima Japan Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8526 Japan Core of Research for the Energetic Universe Hiroshima University Higashi-Hiroshima739-8526 Japan Department of Information Kaishi Professional University Niigata950-0916 Japan Faculty of Science and Engineering Department of Physical Science and Materials Engineering Studies in Mathematical Science and Physics Iwate University Japan

We have investigated an approach to determine the Majorana type-phases using the time evolution of lepton family numbers. The Majorana type-phases are related to the orientation of unitarity triangles for the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix, and the Majorana phases α21 and α31. After taking the second-order time derivative of the lepton family number expectation values, the dependencies on the summation of Majorana type-phases can be determined. Thus allowing for the extraction of the orientation of the unitarity triangles and the Majorana phases. We study how to extract the Majorana type-phases and the lightest neutrino mass for three massive neutrinos, and when a neutrino is massless, i.e., m1,3 = 0. Theoretically, our results indicate lepton number can be used to determine the orientation of the PMNS unitarity triangles and the Majorana phases. To show how the Majorana phases and Majorana-type phases are related to the CP violation for leptogenesis at high energy, we first adopt a parametrization where the diagonal elements of the effective Majorana mass matrix at low energy are given by real positive numbers. In this basis, the phase of the off-diagonal elements related to the CP violating phases in PMNS matrix. We explicitly show the relation between the single Majorana phase and the phase of the effective Majorana mass matrix for two generation case of active neutrinos. Then for type I seesaw model with two gauge singlet neutrinos and two families of lepton doublet, we study the effective Majorana mass matrix generated by the seesaw model. We are able to show how the Majorana phase at low energy is related to two CP violating phases in the seesaw model and the relation between Majorana phase at low energy and CP violating phases related to the lepton number asymmetries of the heavy Majorana neutrinos decays is established. © 2022, CC BY.

关键词： Neutrons

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Measurement of Water Diffusion Coefficient in Cross-Linked Gelatins Using the Terahertz Time-Domain Spectroscopy Technique

Measurement of Water Diffusion Coefficient in Cross-Linked G...

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CLEO: Applications and Technology in CLEO 2024, CLEO: A and T 2024 - Part of Conference on Lasers and Electro-Optics

作者： Walden, D. Chakraborty, D. Cheng, J. Straksys, A. Stirke, A. Melo, W.C.M.A. Jukna, A. Komissarov, I. Sobolewski, Roman Department of Physics and Astronomy University of Rochester RochesterNY14627 United States Laboratory for Laser Energetics University of Rochester RochesterNY14623-1299 United States Materials Science Graduate Program University of Rochester RochesterNY14627 United States State Research Institute Center for Physical Sciences & Technology Vilnius Lithuania Department of Physics Vilnius Gediminas Technical University Vilnius Lithuania Department of Electrical and Computer Engineering University of Rochester RochesterNY14627 United States

A novel method has been developed to evaluate the water diffusion dynamics in gelatin-based gels, based on transient terahertz time-domain spectroscopy measurements. Such gels are widely used models for human skin. &#... 详细信息

关键词： Terahertz spectroscopy

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Decorative coating or corrosion product? TEM and SEM Study on a Late Neolithic Axe to find origins of silver metal on the surface

arXiv

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arXiv 2023年

作者： Saleem, Khurram Schürmann, Ulrich Grandin, Lena Horn, Christian Jürgens, Fritz Müller, Johannes von Carnap-Bornheim, Claus Kienle, Lorenz Institute of Materials Science and Engineering CAU Kiel Germany Institute of Prehistoric and Protohistoric Archaeology CAU Keil Germany Departement of Historical Studies University of Gothenburg Sweden Schleswig-Holstein State Museum Schloss Gottorf Schleswig Germany

Here we report on the analysis of a metallic Late Neolithic copper axe by means of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The axe was found at Eskilstorp, south-west Scania during archaeological excavations in autumn of 2015. It showed a hint of silver enrichment on the surface which is unusual for Late Neolithic axes from Pile type hoard. To identify the origin of the silver content, we extracted a thin lamella of the axe interior using Focused Ion Beam (FIB) technology to reach the internal structure to keep the process extremely minimally invasive. The results revealed the presence of porous external layer of copper oxide enriched with silver particles. It is shown with the corrosion test performed on copper-silver experimental replica that the silver enrichment is attributed to the selective dissolution of copper metal as a resut of corrosion process on the axe. The corrosion experiment is performed in the presence of an organic electrolyte such as Hemic Acid (HA) which replicates soil and natural water environment. In the scope of this research work, we found a strong evidence that the silver on the surface of the axe was not decrative layer and instead remained on the surface due to its more noble character while copper leached out into the soil due to corrosion. Copyright © 2023, The Authors. All rights reserved.

关键词： Copper oxides

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DIRECT OBSERVATION OF DRYING BY NEUTRON AND X-RAY TOMOGRAPHY ANALYSIS 17

DIRECT OBSERVATION OF DRYING BY NEUTRON AND X-RAY TOMOGRAPHY...

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17th Unified International Technical Conference on Refractories, UNITECR 2022

作者： Moreira, M.H. Dal Pont, S. Tengattini, A. Luz, A.P. Cunha, T.M. Ausas, R.F. Pandolfelli, V.C. Federal University of Sao Carlos Graduate Program in Materials Science and Engineering SP Sao Carlos Brazil 3SR Université Grenoble Alpes Grenoble France Large Scale Structures Institut Laue-Langevin Grenoble France Institute of Mathematical and Computer Sciences University of São Paulo São Carlos Brazil

The drying of refractory monolithics is one of the main drawbacks of this class of materials due to its implication on the production halt of many industrial equipment. This is especially true for calcium aluminate cement (CAC)-bonded castables, where the vapor derived from the unreacted water and dehydration reactions can pressurize yielding cracks and explosions of the ceramic lining. Numerous advances on additives have been made to increase these materials' resistance to explosive spalling, however, the fundamentals of the physical phenomena that yields such a problem remain an open issue. For years, the techniques used to study this process were limited to indirect tests, such as the thermogravimetric analysis or the pressure and temperature measurements of samples being unidirectionally heated. Recently, direct techniques such as nuclear magnetic resonance and X-ray tomography were applied in the context of regular concrete on fire scenarios. The current work presents preliminary results of neutron tomography applied to monitoring the drying of refractory castables. The overall behavior of the castable was qualitatively similar to those observed for regular concrete, and the results provide information that can be successfully applied on numerical simulations of larger pieces with dimensions closer to the industrial ones, overcoming the main drawback of such techniques, their small sample dimensions. © 2022 Unified International Technical Conference on Refractories, UNITECR 2022 - Proceedings. All rights reserved.

关键词： Drying

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