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arXiv 2023年

作者： Biborski, Andrzej Zegrodnik, Michal Wójcik, Pawel Nowak, Michal P. Academic Centre for Materials and Nanotechnology AGH University of Krakow Al. Mickiewicza 30 Krakow30-059 Poland Faculty of Physics and Applied Computer Science AGH University of Krakow Al. Mickiewicza 30 Krakow30-059 Poland

We study theoretically the electronic properties of the artificial quantum dot honeycomb lattice defined in a two-dimensional electron gas, focusing on the possibility of achieving a regime in which electronic correlations play a dominant role. At first we establish a non-interacting model compatible with recently studied experimentally devices. According to the values of the obtained electron-electron interaction integrals, we postulate that the inclusion of inherent electron-gas self-screening is indispensable to reconstruct the experimental observations. Applying the Thomas-Fermi type of screening, we show that the radius of the anti-dot is crucial to achieve a correlated state in which phenomena like antiferromagentic ordering and interaction-induced insulating state appear. We estimate the conditions for which the electronically correlated state in an artificial honeycomb lattice can be realized. © 2023, CC BY.

关键词： Electron-electron interactions

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Deep neural networks for smooth approximation of physics with higher order and continuity B-spline base functions

arXiv

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arXiv 2022年

作者： Doleglo, Kamil Paszyńska, Anna Paszyński, Maciej Demkowicz, Leszek Institute of Computer Science AGH University of Science and Technology Kraków Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Oden Institute for Computational and Engineering Sciences The University of Texas at Austin United States

This paper deals with the following important research question. Traditionally, the neural network employs non-linear activation functions concatenated with linear operators to approximate a given physical phenomenon. They "fill the space" with the concatenations of the activation functions and linear operators and adjust their coefficients to approximate the physical phenomena. We claim that it is better to "fill the space" with linear combinations of smooth higher-order B-splines base functions as employed by isogeometric analysis and utilize the neural networks to adjust the coefficients of linear combinations. In other words, the possibilities of using neural networks for approximating the B-spline base functions' coefficients and by approximating the solution directly are evaluated. Solving differential equations with neural networks has been proposed by Maziar Raissi et al. in 2017 [16] by introducing physics-informed Neural Networks (PINN), which naturally encode underlying physical laws as prior information. Approximation of coefficients using a function as an input leverages the well-known capability of neural networks being universal function approximators [6]. In essence, in the PINN approach the network approximates the value of the given field at a given point. We present an alternative approach, where the physcial quantity is approximated as a linear combination of smooth B-spline basis functions, and the neural network approximates the coefficients of B-splines. This research compares results from the DNN approximating the coefficients of the linear combination of B-spline basis functions, with the DNN approximating the solution directly. We show that our approach is cheaper and more accurate when approximating smooth physical fields. © 2022, CC BY.

关键词： Deep neural networks

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Mrs. Correct and majority colorings

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Discrete Mathematics 2025年第11期348卷

作者： Anholcer, Marcin Bosek, Bartłomiej Grytczuk, Jarosław Gutowski, Grzegorz Przybyło, Jakub Zając, Mariusz Institute of Informatics and Quantitative Economics Poznań University of Economics and Business Poznań Poland Institute of Theoretical Computer Science Faculty of Mathematics and Computer Science Jagiellonian University Kraków Poland Faculty of Mathematics and Information Science Warsaw University of Technology Warsaw Poland AGH University of Krakow Faculty of Applied Mathematics al. A. Mickiewicza 30 Kraków 30-059 Poland

A majority coloring of a directed graph is a vertex coloring in which each vertex has the same color as at most half of its out-neighbors. In this note we simplify some proof techniques and generalize previously known results on various generalizations of majority coloring. In particular, our unified and simplified approach works for paintability – an on-line analog of the list coloring. © 2025 The Author(s)

关键词： List coloring Majority coloring Paintability

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Isolation of Microcrystalline Cellulose from Wood and Fabrication of Polylactic Acid(PLA)Based Green Biocomposites

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Journal of Renewable Materials 2024年第8期12卷 1455-1474页

作者： Selwin Maria Sekar Rajini Nagarajan Ponsuriyaprakash Selvakumar Ismail Sikiru Oluwarotimi Kumar Krishnan Faruq Mohammad Mohammed Rafi Shaik Nadir Ayrilmis Department of Mechanical Engineering Kalasalingam Academy of Research and EducationKrishnankoil626126India Department of Mechanical Engineering SSM Institute of Engineering and TechnologyDindigul624002India Department of Engineering Centre for Engineering ResearchSchool of PhysicsEngineering and Computer ScienceUniversity of HertfordshireHatfieldAL109ABUK INTI International University Persiaran Perdana BBNNilai71800Malaysia Department of Chemistry College of ScienceKing Saud UniversityP.O.Box 2455Riyadh11451Kingdom of Saudi Arabia Department of Wood Mechanics and Technology Faculty of ForestryIstanbul University–CerrahpasaBahcekoySariyerIstanbul34473Turkey

An innovative microcrystalline cellulose(MCC)natural fibre powder-reinforced PLA biocomposite was investigated using the hand lay-up *** polymer matrix composite(PMC)samples were prepared by varying the weight percentages(wt.%)of both PLA matrix and MCC reinforcement:pure PLA/100:0,90:10,80:20,70:30,60:40 and 50:50 wt.%,*** the results obtained,MCC powder,with its impressive aspect ratio,proved to be an ideal reinforcement for the PLA,exhibiting exceptional mechanical *** was evident that the 80:20 wt.%biocomposite sample exhibited the maximum improvement in the tensile,flexural,notched impact,compressive strength and hardness by 28.85%,20.00%,91.66%,21.53%and 35.82%,respectively compared to the pure PLA ***,during the thermogravimetric analysis(TGA),the same 80:20 wt.%biocomposite sample showed a minimum weight loss of 20%at 400℃,among *** morphological study using Field Emission Scanning Electron Microscopy(FE-SEM)revealed that the uniform distribution of cellulose reinforcement in the PLA matrix actively improved the mechanical properties of the biocomposites,especially the optimal 80:20 wt.%***,it was evident that the optimal PLA/cellulose biocomposite sample could be a suitable and alternative sustainable,environmentally friendly and biodegradable material for semi/structural applications,replacing synthetic and traditional components.

关键词： Polylactic acid micro crystalline cellulose biocomposite characterizations FESEM environmental pollution

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Quantifying colors at micrometer scale by colorimetric microscopy (C-Microscopy) approach

arXiv

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arXiv 2023年

作者： Jany, Benedykt R. Marian Smoluchowski Institute of Physics Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Krakow30348 Poland

The color is the primal property of the objects around us and is direct manifestation of light-matter interactions. The color information is used in many different fields of science, technology and industry to investigate material properties or for identification of concentrations of substances. Usually the color information is used as a global parameter in a macro scale. To quantitatively measure color information in micro scale one needs to use dedicated microscope spectrophotometers or specialized micro-reflectance setups. Here, the Colorimetric Microscopy (C-Microscopy) approach based on digital optical microscopy and a free software is presented. The C-Microscopy approach uses color calibrated image and colorimetric calculations to obtain physically meaningful quantities i. e., dominant wavelength and excitation purity maps at micro level scale. This allows for the discovery of the local color details of samples surfaces. Later, to fully characterize the optical properties, the hyperspectral reflectance data at micro scale (reflectance as a function of wavelength for a each point) are colorimetrically recovered. The C-Microscopy approach was successfully applied to various types of samples i.e., two metamorphic rocks unakite and lapis lazuli, which are mixtures of different minerals;and to the surface of gold 99.999 % pellet, which exhibits different types of surface features. The C-Microscopy approach could be used to quantify the local optical properties changes of various materials at microscale in an accessible way. The approach is freely available as a set of python jupyter notebooks. © 2023, CC BY.

关键词： Color

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A Pseudo-Spectral Scheme for Systems of Two-Point Boundary Value Problems with Left and Right Sided Fractional Derivatives and Related Integral Equations

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computer Modeling in Engineering & sciences 2021年第7期128卷 21-41页

作者： I.G.Ameen N.A.Elkot M.A.Zaky A.S.Hendy E.H.Doha Department of Mathematics Faculty of ScienceAl-Azhar UniversityCairoEgypt Department of Mathematics Faculty of ScienceCairo UniversityGiza12613Egypt Department of Applied Mathematics Physics DivisionNational Research CentreDokkiCairo12622Egypt Department of Computational Mathematics and Computer Science Institute of Natural Sciences and MathematicsUral Federal UniversityYekaterinburg620002Russia Department of Mathematics Faculty of ScienceBenha UniversityBenha13511Egypt

We target here to solve numerically a class of nonlinear fractional two-point boundary value problems involving left-and right-sided fractional *** main ingredient of the proposed method is to recast the problem into an equivalent system of weakly singular integral ***,a Legendre-based spectral collocation method is developed for solving the transformed ***,we can make good use of the advantages of the Gauss quadrature *** present the construction and analysis of the collocation *** results can be indirectly applied to solve fractional optimal control problems by considering the corresponding Euler–Lagrange *** numerical examples are given to confirm the convergence analysis and robustness of the scheme.

关键词： Spectral collocation method weakly singular integral equations two-point boundary value problems convergence analysis

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Superconductivity near the Mott-Ioffe-Regel limit in the high-entropy alloy superconductor (ScZrNb)1−x(RhPd)x with a CsCl-type lattice

arXiv

引用

arXiv 2023年

作者： Gutowska, Sylwia Kawala, Alicja Wiendlocha, Bartlomiej Faculty of Physics and Applied Computer Science AGH University of Science and Technology Aleja Mickiewicza 30 Krakow30-059 Poland Department of Quantum Many-Body Theory Jagiellonian University ul. prof. S. Lojasiewicza 11 Krakow30-348 Poland

Theoretical analysis of the electronic structure of the high-entropy-type superconductor (ScZrNb)1−x(RhPd)x, x ∈ (0.35,0.45) is presented. The studied material is a partially ordered CsCl-type structure, with two sublattices, randomly occupied by Sc, Zr, Nb (first sublattice) and Nb, Rh, and Pd (second sublattice). Calculations were done using the Korringa-Kohn-Rostoker method with the coherent potential approximation (KKR-CPA) and take into account the substitutional disorder. Our total energy calculations confirm the preference for the partially ordered structure over the fully random bcc-type one. Electronic densities of states N(E), dispersion relations, and McMillan-Hopfield parameters η (electronic contribution to electron-phonon coupling) are studied as a function of composition. The computed increasing trends in N(EF) and η with x are opposite to what we expected based on the experimental results, where the decrease in the critical temperature with increasing x was found. Very strong electron scattering due to disorder is observed, as the electronic dispersion relations are strongly smeared. As a result, the computed electronic lifetimes τ are very short, leading to a small mean-free path of electrons of the order of interatomic distance, which puts (ScZrNb)1−x(RhPd)x near the Mott-Ioffe-Regel limit. The trend in τ(x) is similar to the trend observed experimentally in Tc(x), suggesting that disorder may be the factor that influences Tc in this series of alloys. Copyright © 2023, The Authors. All rights reserved.

关键词： Crystal structure

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ML-based Expert Products Scoring System

ML-based Expert Products Scoring System

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Progress in applied Electrical Engineering (PAEE)

作者： Patryk Mendoń Mariusz Pelc Aleksandra Kawala-Sterniuk Mariusz Gola Faculty of Electrical Engineering Automatic Control and Informatics Opole University of Technology Opole Poland Faculty of Mathematics Physics and Computer Science University of Opole Opole Poland

ISBN: (数字)9798331527563

ISBN: (纸本)9798331527570

In this paper the authors propose a system architecture which allows product scoring based on sentiment analysis and utilising Machine Learning (ML) and Expert systems technologies. This solution presented in this paper allows decoupling the AI-based part, which is very capable in sentiment analysis but is lacking some flexibility to actually put the sentiment analysis results in a wider context to make a better sense as to what the results actually mean. This task in our solution is performed by the Expert system where the expert may provide some decision making rules in order to determine the final system *** results confirm discrepancy between reviews and star ratings.

关键词： Knowledge engineering Fuzzy logic Sentiment analysis Reviews Systems architecture Stars Machine learning Cognition Expert systems System analysis and design

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Operating Point Shift Induced by Relay Asymmetry: An Iterative Solution Proposal

Operating Point Shift Induced by Relay Asymmetry: An Iterati...

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International Conference on Process Control (PC)

作者： Libor Pekař Radek Matušů Hubert Guzowski František Gazdoš Faculty of Applied Informatics Tomas Bata University in Zlín nám T. G. Masaryka 5555 Zlín Czech Republic Institute of Computer Science AGH University of Science and Technology Krakow Poland

This contribution focuses on a problem that appears when using a relay with non-symmetric output in the closed loop. Such a scheme is usually used for process model parameters identification, possibly followed by automatic controller tuning. Whenever static or dynamic properties of the process reveal asymmetry when the sign of the input changes, the setpoint (reference) becomes different from the operating point value of the process output. As a class of relay-based identification methods utilize calculations in the frequency domain that are based on integral computation around the operating point, the discrepancy between the setpoint and the operating point can lead to incorrect results. The aim of the paper is mainly to provide the reader with problem formulation and step-by-step proposition of how it can be solved. Concise numerical examples are also given. The concluding remarks suggest possible further ways of research.

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Investigating the shunting effect in a Fe/Co ferromagnetic metal hybrid structure and its impact on the spin Seebeck effect

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Physical Review B 2024年第10期109卷 104423-104423页

作者： Santi Phumying Chalothon Wongjom Ekkarat Pongophas Yingyot Infahsaeng Wasan Maiaugree Rungrueang Pattanakul Mati Horprathum Chanunthorn Chananonnawathorn Piyawat Piyasin Supree Pinitsoontorn Harihara Ramamoorthy Ratchanok Somphonsane Wanchai Pijitrojana Sarute Ummartyotin Pruet Kalasuwan Poramed Wongjom Division of Physics Faculty of Science and Technology Thammasat University Pathum Thani 12120 Thailand Synchrotron Light Research Institute Nakhon Ratchasima 30000 Thailand Opto-Electrochemical Sensing Research Team Spectroscopic and Sensing Devices Research Group National Electronics and Computer Technology Center Pathum Thani 12120 Thailand Department of Physics Faculty of Science Khon Kaen University Khon Kaen 40002 Thailand Department of Electronics Engineering School of Engineering King Mongkut's Institute of Technology Ladkrabang Bangkok 10520 Thailand Department of Physics School of Science King Mongkut's Institute of Technology Ladkrabang Bangkok 10520 Thailand Electrical and Computer Engineering Department Thammasat School of Engineering Thammasat University Rangsit Campus Klongluang Pathumthani 12120 Thailand Department of Materials and Textile Technology Faculty of Science and Technology Thammasat University Klongluang Pathum Thani 12120 Thailand Division of Physical Science Faculty of Science Prince of Songkla University Hat Yai Songkhla 90110 Thailand

The generation of spin voltage by heat, known as the spin Seebeck effect (SSE), involves the injection of spin current from a ferromagnetic to a normal metal. In this study, the shunting effect in SSE is investigated within a hybrid structure consisting of iron (Fe) and cobalt (Co) films deposited on a Si-wafer substrate using thermal evaporation [Si/Fe(500 nm)/Co(10 nm)]. Spin voltage measurements performed in the in-plane configuration revealed a voltage reversal in the Co film and Fe film. However, in the hybrid structure (Si/Fe/Co), the voltage signal exhibited consistent directionality. This intriguing observation hints at a potential shunting effect, wherein the voltage influence from the Fe layer contributes to the Co film. Consequently, it is deduced that a significant shunting effect occurs when the resistivity of Fe is approximately three orders of magnitude lower than that of the Co film. This insight sheds light on the intricate dynamics of spin thermoelectric applications, emphasizing the role of material properties in optimizing performance.

关键词： Charge Diffusion Electrical properties Magnetic coupling Magnetism Spin dynamics Spin-orbit coupling Spintronics Temperature Thermal properties

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