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The construction and characterization of MgO transmission dynodes

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arXiv 2023年

作者： Chan, H.W. Prodanović, V. Theulings, A.M.M.G. Tao, S. Smedley, J. Hagen, C.W. Sarro, P.M. Graaf, H.V.D. Science Park 105 Amsterdam1098 XG Netherlands Faculty of Electrical Engineering Mathematics and Computer Science Department of Microelectronics ECTM Delft University of Technology Feldmannweg 17 Delft2628 CT Netherlands Faculty of Applied Sciences Department of Imaging Physics Delft University of Technology Lorentzweg 1 Delft2628 CJ Netherlands Department of Applied Physics Eindhoven University of Technology Eindhoven5600 MB Netherlands SLAC National Accelerator Laboratory Stanford University 2575 Sand Hill Road Menlo ParkCA94025 United States

In this work we demonstrate that ultra-thin (5 and 15 nm) MgO transmission dynodes with sufficient high transmission electron yield (TEY) can be constructed. These transmission dynodes act as electron amplification stages in a novel vacuum electron multiplier: the Timed Photon Counter. The ultra-thin membranes with a diameter of 30 µm are arranged in a square 64-by-64-array. The TEY was determined with a scanning electron microscope using primary electrons with primary energies of 0.75 - 5 keV. The method allows a TEY map of the surface to be made while simultaneously imaging the surface. The TEY of individual membranes can be extracted from the TEY map. An averaged maximum TEY of 4.6 ± 0.2 was achieved by using 1.35 keV primary electrons on a TiN/MgO bi-layer membrane with a layer thickness of 2 and 5 nm, respectively. The TiN/MgO membrane with a layer thickness of 2 and 15 nm, respectively, has a maximum TEY of 3.3 ± 0.1 (2.35 keV). Furthermore, the effect of the electric field strength on transmission (secondary) electron emission was investigated by placing the emission surface of a transmission dynode in close proximity to a planar collector. By increasing the electric potential between the transmission dynode and the collector, from -50 V to -100 V, the averaged maximum TEY improved from 4.6 ± 0.2 to 5.0 ± 0.3 at a primary energy of 1.35 keV with an upper limit of 5.5 on one of the membranes. Copyright © 2023, The Authors. All rights reserved.

关键词： Electrons

Neural network reconstruction of cosmology using the Pantheon compilation

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arXiv 2023年

作者： Dialektopoulos, Konstantinos F. Mukherjee, Purba Said, Jackson Levi Mifsud, Jurgen Department of Mathematics and Computer Science Transilvania University of Brasov Eroilor 29 Brasov Romania Laboratory of Physics Faculty of Engineering Aristotle University of Thessaloniki Thessaloniki54124 Greece Physics and Applied Mathematics Unit Indian Statistical Institute Kolkata700108 India Institute of Space Sciences and Astronomy University of Malta MSD 2080 Malta Department of Physics University of Malta MSD 2080 Malta

In this work, we reconstruct the Hubble diagram using various data sets, including correlated ones, in Artificial Neural Networks (ANN). Using ReFANN, that was built for data sets with independent uncertainties, we expand it to include non-Guassian data points, as well as data sets with covariance matrices among others. Furthermore, we compare our results with the existing ones derived from Gaussian processes and we also perform null tests in order to test the validity of the concordance model of cosmology. Copyright © 2023, The Authors. All rights reserved.

关键词： Cosmology

Neural network reconstruction of scalar-tensor cosmology

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arXiv 2023年

Neural networks have shown great promise in providing a data-first approach to exploring new physics. In this work, we use the full implementation of late time cosmological data to reconstruct a number of scalar-tensor cosmological models within the context of neural network systems. In this pipeline, we incorporate covariances in the data in the neural network training algorithm, rather than a likelihood which is the approach taken in Markov chain Monte Carlo analyses. For general subclasses of classic scalar-tensor models, we find stricter bounds on functional models which may help in the understanding of which models are observationally viable. Copyright © 2023, The Authors. All rights reserved.

关键词： Cosmology

KNOWLEDGE-BASED DATASET FOR TRAINING PE MALWARE DETECTION MODELS

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arXiv 2022年

作者： Švec, Peter Balogh, Štefan Homola, Martin Kl’uka, Ján Institute of Computer Science and Mathematics Faculty of Electrical Engineering and Information Technology Slovak University of Technology Ilkovičova 3 Bratislava Slovakia Department of Applied Informatics Faculty of Mathematics Physics and Informatics Comenius University Mlynská dolina Bratislava Slovakia

Ontologies are a standard for semantic schemata in many knowledge-intensive domains of human interest. They are now becoming increasingly important also in areas until very recently dominated by subsymbolic representations and machine-learning-based data processing. One such area is information security, and more specifically malware detection. We propose PE Malware Ontology that offers a reusable semantic schema for Portable Executable (PE, Windows binary format) malware files. The ontology was inspired by the structure of the data in the EMBER dataset and it currently covers the data intended for static malware analysis. With this proposal, we hope to achieve: a) a unified semantic representation for PE malware datasets that are available or will be published in the future;(b) applicability of symbolic, neural-symbolic, or otherwise explainable approaches in the PE Malware domain that may lead to improved interpretability of results which may now be characterized by the terms defined in the ontology;and (c) by joint publishing of semantically treated EMBER data, including fractional datasets, also improved reproducibility of experiments. Copyright © 2022, The Authors. All rights reserved.

关键词： Ontology

Relationships between Microbiological and Physicochemical Properties of Substrata, Fungal Root Colonisation and Plant Performance of Commercially Available Ornamental Plant Species Grown in Pots

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SSRN

SSRN 2024年

作者： Móll, Maciej Skubala, Kaja Baran, Katarzyna Wróbel, Maria Rożek, Katarzyna Stanek, Malgorzata Orzechowska, Aleksandra Zubek, Szymon Institute of Botany Faculty of Biology Jagiellonian University in Kraków Gronostajowa 3 Kraków30-387 Poland W. Szafer Institute of Botany Polish Academy of Sciences Lubicz 46 Kraków31-512 Poland Faculty of Physics and Applied Computer Science AGH University of Kraków Al. Mickiewicza 30 Kraków30-059 Poland

The relationships of ornamental plants with soil microorganisms, which can either stimulate or suppress their performance and thereby impact the production process, remain largely unexplored. Therefore, we conducted a study on 10 common ornamental plant species available in large DIY stores to compare the microbiological and physicochemical properties of substrata used for their cultivation and assess their colonisation by root-inhabiting fungi, namely arbuscular mycorrhizal fungi (AMF), dark septate endophytes (DSE), and Olpidium. The substrata exhibited significant variations in their microbiological and physicochemical properties, depending on both their origin from DIY stores and the ornamental plant species. Hyphae and spores of AMF were not found in any analysed roots and substrata, respectively, except for the low level of colonisation observed in Echinacea purpurea roots. However, 8 plant species were colonised by DSE and 8 by Olpidium spp. More acidic substrata with a high content of organic matter and the ability to hold water favoured the colonisation of Olpidium spp. in roots, and the opposite trend was found for DSE. The occurrence of both groups of endophytes, especially Olpidium, was limited in plants with higher biomass and vitality. In conclusion, commercially available ornamental plant species rarely form symbiotic associations with AMF in pot cultivation. Instead, they are often colonised by other root-inhabiting fungi, such as DSE, which are known to have either positive or negative effects on their hosts, and Olpidium spp., which can transfer plant viruses. We suspect that these results are due to high nutrient, organic matter, and water contents in substrata. © 2024, The Authors. All rights reserved.

关键词： Fungi

Magnon Shake-up: Entanglement Generation and Sensing

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arXiv 2025年

作者： Azimi-Mousolou, Vahid Sjöqvist, Erik Delin, Anna Eriksson, Olle Department of Applied Mathematics and Computer Science Faculty of Mathematics and Statistics University of Isfahan Isfahan81746-73441 Iran Department of Physics and Astronomy Uppsala University Box 516 UppsalaSE-751 20 Sweden Department of Applied Physics School of Engineering Sciences KTH Royal Institute of Technology AlbaNova University Center StockholmSE-10691 Sweden Swedish e-Science Research Center KTH Royal Institute of Technology StockholmSE-10044 Sweden KTH Royal Institute of Technology StockholmSE-10044 Sweden WISE-Wallenberg Inititative Materials Science Uppsala University Box 516 UppsalaSE-751 20 Sweden

Shake-up phenomena, rooted in the sudden approximation and many-body quantum dynamics, unveil critical characteristics of quantum systems, with wide-ranging applications in molecular spectroscopy and electronic structure studies. Here, this principle is extended to magnetic systems, and magnon shake-up structures and their relevance in generating and sensing magnon-magnon entanglement are demonstrated. This not only reveals new insights into shake-up phenomena and quantum magnetism but also paves the way for new opportunities in quantum technologies. © 2025, CC BY.

关键词： Quantum entanglement

High pressure microreactor for minute amounts of catalyst on planar supports: a case study of CO2 hydrogenation over Pd0.25Zn0.75Ox nanoclusters

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SSRN

SSRN 2024年

作者： Abbas, Imran Romeggio, Filippo Pilarczyk, Kacper Kuhn, Simon Damsgaard, Christian Danvad Kibsgaard, Jakob Lievens, Peter Grandjean, Didier Janssens, Ewald Quantum Solid-State Physics Department of Physics and Astronomy KU Leuven Celestijnenlaan 200D Leuven3001 Belgium Department of Physics Technical University of Denmark Kongens Lyngby2800 Denmark Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. A. Mickiewicza 30 Kraków30-059 Poland Department of Chemical Engineering KU Leuven Celestijnenlaan 200F Leuven3001 Belgium National Centre for Nano Fabrication and Characterization Technical University of Denmark Kongens Lyngby2800 Denmark

igh-pressure studies of well-defined catalysts, deposited on planar supports in ultra-high vacuum using physical methods, may bridge the gap between surface science and applied catalysis approaches in order to develop better catalysts for crucial reactions such as CO2 hydrogenation. However, the chemical reactors necessary for such investigations, typically involving catalyst quantities down to a few hundred nanograms, are lacking. We present the novel design and evaluation of a 50 µL rectangular microchannel reactor capable of testing small quantities of catalyst at pressures up to 40 bar and temperatures up to 240°C. To evaluate the microreactor performance, Pd0.25Zn0.75Ox nanoclusters soft-landed on SiO2-coated mica sheets using the cluster beam deposition technique, were tested for the reverse water-gas shift reaction through a series of kinetic experiments. Experimental results, combined with computational fluid dynamics and mass transport analysis, demonstrate that the proposed microreactor setup allows for testing minute quantities of catalysts with very high sensitivity at industrially relevant temperatures and pressures. Although not restricted to a particular catalyst preparation method, the setup is an excellent platform for conducting catalytic tests on composition-controlled, mass-selected, gas-phase nanoparticles deposited on planar substrates, facilitating the determination of reliable structure-activity relationships and enabling a more rational design of catalysts © 2024, The Authors. All rights reserved.

关键词： Water gas shift

Mechanisms of Formation and Modeling of the Refractory Compound Film Structures

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Mechanisms of Formation and Modeling of the Refractory Compo...

International Conference on Nanomaterials: Application & Properties (NAP)

作者： Alexander Goncharov Ivan Kolinko Dmytro Shyrokorad Grygoriy Kornich Andrii Yunda Svetlana Goncharova Department of Applied Mathematics and Complex Systems Modelling Sumy State University Sumy Ukraine Institute of Materials Science Slovak University of Technology in Bratislava Slovak Republic Computer Sciences and Technologies Faculty National University “Zaporizhzhia Polytechnic” Zaporizhzhia Ukraine Institute of Applied Physics National Academy of Sciences of Ukraine Sumy Ukraine Department of Biophysics Biochemistry Pharmacology and Biomolecular Engineering Sumy State University Sumy Ukraine

ISBN: (数字)9798350380125

ISBN: (纸本)9798350380132

In this work, the molecular dynamics method was used for modeling the formation of critical nuclei at the initial stage. The deposition of a titanium nitride film on an iron substrate was chosen as a model object. The 2NN MEAM multiatomic potential was used to calculate the interaction between atoms. Simulations of N and Ti atom deposition on an Fe(100) substrate were carried out using the MPI version of the open-source program LAMMPS (Molecular Dynamics Simulator). The substrate was modeled as a semi-infinite crystal with a frozen lower atomic layer, periodic boundary conditions at the lateral crystal sides, and a free deposition surface.

关键词： Atomic layer deposition Crystals Atoms Titanium nitride Boundary conditions Iron Compounds Substrates Surface treatment

Effect of Annealing Temperature and MoO3 Composition on the Mechanical Properties of PEDOT:PSS-MoO3 Blend Thin Film Layers for Organic Solar Cells and Organic Light Emitting Diodes Applications

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Effect of Annealing Temperature and MoO3 Composition on the ...

Multidisciplinary Engineering and applied science (ICMEAS), International Conference on

作者： Kum Tatchen Buh Daniel Iramofu Amune Vitalis Chioh Anye Odette Fayen Ngasoh Abdulhakeem Bello Sadiq Thomas Department of Materials Science and Engineering African University of Science and Technology (AUST) Abuja Nigeria Department of Materials Science and Engineering Department of Electical-Electronics Engineering Faculty of Engineering African University of Science and Technology (AUST) Nile University of Nigeria Abuja Nigeria Department of Mechanical Engineering African University of Science and Technology (AUST) Abuja Nigeria Department of Theoritical & Applied Physics African University of Science and Technology (AUST) Abuja Nigeria Department of Computer Engineering Faculty of Engineering Nile University of Nigeria Abuja Abuja Nigeria

ISBN: (数字)9798350358834

ISBN: (纸本)9798350358841

Experimental and computational methods are employed in this study to examine how varying heat treatment temperatures and composition of Moo3nanoparticles, a transition metal oxide (TMO) impact the mechanical properties of PEDOT:PSS/MoO3 thin film blends for organic photovoltaics (OPVs) and organic light emitting diode (OLED) applications. The study primarily investigates the mechanical properties (hardness and Young's modulus), microstructure and surface morphology of solution-processed PEDOT:PSS/MoO3 ink blends of different compositions prepared at temperature regimes between 60 to 120 °C. Nanoindentation is used to investigate mechanical properties and Scanning Probe Microscopy to examine the surface morphological and microstructural changes. Mechanical maps and statistical deconvolutions are used to show the distribution of mechanical properties and phases respectively in the PEDOT:PSS/Mo03 thin film blends at the different annealing temperatures (60 - 120 °C). The experimental and computational results lead to the conclusion that incorporating different percentages of Moo3into PEDOT:PSS can, depending on the blended ratio improve the microstructure, mechanical properties and surface morphology of the PEDOT:PSS/MoO3 blends. Lightly doped PEDOT:PSS/MoO3 blends (1:0.1, 1:0.3), generally exhibit improved surface morphologies, enhanced elastic modulus and hardness, suitable for applications in efficient and mechanically durable electronic devices.

关键词： Temperature Annealing Surface morphology Morphology Organic light emitting diodes Mechanical factors Microstructure