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arXiv 2024年

作者： Deptuch, Aleksandra Górska, Natalia Baran, Stanislaw Urbańska, Magdalena Institute of Nuclear Physics Polish Academy of Sciences Radzikowskiego 152 KrakówPL-31342 Poland Faculty of Chemistry Jagiellonian University Gronostajowa 2 KrakówPL-30387 Poland Jagiellonian University Faculty of Physics Astronomy and Applied Computer Science M. Smoluchowski Institute of Physics Lojasiewicza 11 KrakówPL-30-348 Poland Institute of Chemistry Military University of Technology Kaliskiego 2 WarsawPL-00908 Poland

Molecular arrangement in the chiral smectic phases of the glassforming (S)-4’-(1methylheptylcarbonyl)biphenyl-4-yl 4-[7-(2,2,3,3,4,4,4-heptafluorobutoxy) heptyl-1-oxy]benzoate is investigated by X-ray diffraction. An increased correlation length of the positional short-range order in the supercooled state agrees with the previous assumption of the hexatic smectic phase. However, the registered X-ray diffraction patterns are not typical for the hexatic phases. Comparison of the smectic layer spacing and optical tilt angle indicates a strongly non-linear shape of molecules, which enables choice of the molecular models obtained by DFT calculations, used subsequently to interpret the infrared spectra. The presumption of the hexatic smectic FA* or IA* phase is supported by the splitting of the absorption bands related to the C=O stretching in the supercooled state, which is absent in the smectic CA* phase above the melting temperature. The glass transition affects the temperature dependence of the smectic layer spacing but only subtly impacts the infra-red spectra. Application of the k-means cluster analysis enables distinction between the infra-red spectra below and above the glass transition temperature, but only for certain spectral ranges. © 2024, CC BY.

关键词： Glass transition

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Resource engines

arXiv 2023年

作者： Wojewódka-Ściążko, Hanna Puchala, Zbigniew Korzekwa, Kamil Institute of Mathematics University of Silesia in Katowice Bankowa 14 Katowice40-007 Poland Institute of Theoretical and Applied Informatics Polish Academy of Sciences Baltycka 5 Gliwice44-100 Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland

In this paper we aim to push the analogy between thermodynamics and quantum resource theories one step further. Previous inspirations were based predominantly on thermodynamic considerations concerning scenarios with a single heat bath, neglecting an important part of thermodynamics that studies heat engines operating between two baths at different temperatures. Here, we investigate the performance of resource engines, which replace the access to two heat baths at different temperatures with two arbitrary constraints on state transformations. The idea is to imitate the action of a two-stroke heat engine, where the system is sent to two agents (Alice and Bob) in turns, and they can transform it using their constrained sets of free operations. We raise and address several questions, including whether or not a resource engine can generate a full set of quantum operations or all possible state transformations, and how many strokes are needed for that. We also explain how the resource engine picture provides a natural way to fuse two or more resource theories, and we discuss in detail the fusion of two resource theories of thermodynamics with two different temperatures, and two resource theories of coherence with respect to two different bases. © 2023, CC BY.

关键词： Temperature

RELEVANCE OF MONTE CARLO SIMULATION VALIDATION ANALYSIS IN THE SCOPE OF THE DOSE-3D PROJECT

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Acta Physica Polonica B, Proceedings Supplement

Acta Physica Polonica B, Proceedings Supplement 2022年第4期15卷

作者： Górska, Wioleta Rachwal, Bartlomiej Szumlak, Tomasz Department of Medical Physics Maria Sklodowska-Curie National Research Institute of Oncology Kraków Branch Garncarska 11 Kraków31-115 Poland AGH University of Science and Technology Faculty of Physics and Applied Computer Science Mickiewicza 30 Kraków30-059 Poland Cracow University of Technology Faculty of Materials Science and Physics Warszawska 24 Kraków31-155 Poland

We present an analysis of the characteristics of a therapeutic photon beam simulated by the G4RT simulator which is based on the Monte Carlo method. Development of the G4RT is a part of the Dose-3D project. In order to verify the reliability of the implemented simulator, spatial dose distributions were compared with the real measurements and results from the PRIMO simulator. For the purpose of assessment, the primary photons analysis was performed. Results show the reliability of the G4RT. Therefore, the simulator can be used in further research. © 2022 Jagellonian University. All rights reserved.

关键词： Monte Carlo methods

Constrained Hybrid Metaheuristic Algorithm for Probabilistic Neural Networks Learning

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arXiv 2025年

作者： Kowalski, Piotr A. Kucharczyk, Szymon Mańdziuk, Jacek Faculty of Physics and Applied Computer Science AGH University of Krakow al. A. Mickiewicza 30 Cracow30-059 Poland Systems Research Institute Polish Academy of Sciences ul. Newelska 6 Warsaw01-447 Poland AGH Doctoral School AGH University of Krakow al. A. Mickiewicza 30 Cracow30-059 Poland Faculty of Mathematics and Information Science Warsaw University of Technology Koszykowa 75 Warsaw00-662 Poland Faculty of Computer Science AGH University of Krakow al. A. Mickiewicza 30 Cracow30-059 Poland

This study investigates the potential of hybrid metaheuristic algorithms to enhance the training of Probabilistic Neural Networks (PNNs) by leveraging the complementary strengths of multiple optimisation strategies. Traditional learning methods, such as gradient-based approaches, often struggle to optimise high-dimensional and uncertain environments, while single-method metaheuristics may fail to exploit the solution space fully. To address these challenges, we propose the constrained Hybrid Metaheuristic (cHM) algorithm, a novel approach that combines multiple population-based optimisation techniques into a unified framework. The proposed procedure operates in two phases: an initial probing phase evaluates multiple metaheuristics to identify the best-performing one based on the error rate, followed by a fitting phase where the selected metaheuristic refines the PNN to achieve optimal smoothing parameters. This iterative process ensures efficient exploration and convergence, enhancing the network’s generalisation and classification accuracy. cHM integrates several popular metaheuristics, such as BAT, Simulated Annealing, Flower Pollination Algorithm, Bacterial Foraging Optimization, and Particle Swarm Optimisation as internal optimisers. To evaluate cHM performance, experiments were conducted on 16 datasets with varying characteristics, including binary and multiclass classification tasks, balanced and imbalanced class distributions, and diverse feature dimensions. The results demonstrate that cHM effectively combines the strengths of individual metaheuristics, leading to faster convergence and more robust learning. By optimising the smoothing parameters of PNNs, the proposed method enhances classification performance across diverse datasets, proving its application flexibility and efficiency. © 2025, CC BY-NC-ND.

关键词： Contrastive Learning

Crystallization kinetics of equimolar liquid crystalline mixture and its components

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arXiv 2024年

作者： Deptuch, Aleksandra Paliga, Anna Drzewicz, Anna Piwowarczyk, Marcin Urbańska, Magdalena Juszyńska-Galązka, Ewa Institute of Nuclear Physics Polish Academy of Sciences Radzikowskiego 152 KrakówPL-31342 Poland Faculty of Physics and Applied Computer Science AGH University of Kraków Reymonta 19 KrakówPL-30059 Poland Institute of Chemistry Military University of Technology Kaliskiego 2 WarsawPL-00908 Poland Research Center for Thermal and Entropic Science Graduate School of Science Osaka University Osaka560-0043 Japan

The new equimolar mixture comprises liquid crystalline compounds MHPOBC and partially fluorinated 3F2HPhF6. The phase sequence of the mixture is determined by differential scanning calorimetry, polarizing optical microscopy, X-ray diffraction, and broadband dielectric spectroscopy. The enantiotropic smectic A*, C*, and CA* phases are observed for the mixture. Only partial crystallization of the mixture is observed during cooling at 2-40 K/min and the remaining smectic CA* phase undergoes vitrification. In contrast, the crystallization of the pure components is complete or almost complete for the same range of cooling rates. The kinetics of the non-isothermal and isothermal crystallization of the mixture and pure components are investigated by differential scanning calorimetry. The non-isothermal data are analyzed by the isoconversional method, while the isothermal data are analyzed using the Avrami model. Typically, the nucleation-controlled crystallization kinetics are observed. © 2024, CC BY.

关键词： Differential scanning calorimetry

Impedance Spectroscopy of NaBi(MoO4)2:Gd3+ Nanocrystals in the Pores of an Opal Matrix 1

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8th International science and Practice Conference Nanotechnology and Nanomaterials, NANO 2020

作者： Sal, Bilal Abu Hamam, Khalil J. Moiseyenko, V.N. Ohiienko, O.V. Derhachov, M.P. Holochalov, D.O. Applied Physics Department Faculty of Science Tafila Technical University Al-Eis 66141 P.O. Box 40 Tafila Jordan Physics Electronics and Computer Systems Department Oles Honchar Dnipro National University Prospect Gagarina 72 Dnipro49010 Ukraine

ISBN: (数字)9783030747411

ISBN: (纸本)9783030747404

Nanocomposite based on synthetic opal soaked with the NaBi(MO4)2:Gd3+ melt was characterized by X-ray diffraction patterns and Raman spectroscopy technique. Crystalline state of the substance inside opal pores is proved for composite. The angular positions and intensities of reflections in X-ray diffractograms were different for nanocrystals compared to crystal. Raman spectrum of opal-NaBi(MoO4)2:Gd3+ is not essentially changed compared to that of the single crystal, except for a shift of some Raman bands. The total conductivity of nanocrystals was measured in the frequency range from 1 Hz to 1 MHz and temperature range from 290 to 473 K. Impedance hodographs (Nyquist plots) for nanocomposite were plotted. The energy of activation of conductivity and the nature of its frequency dependence are determined. Hopping conduction mechanism was established. Comparison of the temperature dependence with theory made it possible to estimate the average size of nanocrystals in the pores of opal. © 2021, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Nanocrystals

Characterization of two electronic subsystems in cuprates through optical conductivity

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Physical Review B 2023年第14期107卷 144515-144515页

作者： C. M. N. Kumar A. Akrap C. C. Homes E. Martino B. Klebel-Knobloch W. Tabis O. S. Barišić D. K. Sunko N. Barišić Institute of Solid State Physics TU Wien 1040 Vienna Austria Institute of Physics Bijenička cesta 46 HR-10000 Zagreb Croatia The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences 152 Radzikowskiego Strasse 31-342 Krakow Poland Department of Physics University of Fribourg Chemin du Musée 3 CH-1700 Fribourg Switzerland Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USA National Synchrotron Light Source II Brookhaven National Laboratory Upton New York 11973 USA Institute of Physics École Polytechnique Fédéral de Lausanne (EPFL) CH-1015 Lausanne Switzerland AGH University of Science and Technology Faculty of Physics and Applied Computer Science 30-059 Krakow Poland Department of Physics Faculty of Science University of Zagreb Bijenička cesta 32 HR-10000 Zagreb Croatia

Understanding the physical properties of unconventional superconductors as well as of other correlated materials presents a formidable challenge. Their unusual evolution with doping, frequency, and temperature has frequently led to non-Fermi-liquid (non-FL) interpretations. Optical conductivity is a major challenge in this context. Here, the optical spectra of two archetypal cuprates, underdoped HgBa2CuO4+δ and optimally doped Bi2Sr2CaCu2O8+δ, are interpreted based on the standard Fermi-liquid (FL) paradigm. At both dopings, perfect frequency-temperature FL scaling is found to be modified by the presence of a second, gapped electronic subsystem. This non-FL component emerges as a well-defined mid-infrared spectral feature after the FL contribution, determined independently by transport, is subtracted. Temperature, frequency, and doping evolution of the MIR feature identify a gapped rather than dissipative response. In contrast, the dissipative response is found to be relevant for pnictides and ruthenates. Such an unbiased FL/non-FL separation is extended across the cuprate phase diagram, capturing all the key features of the normal state and providing a natural explanation why the superfluid density is attenuated on the overdoped side. Thus, we obtain a unified interpretation of optical responses and transport measurements in all analyzed physical regimes and all analyzed compounds.

关键词： Electrical properties Localization Microphase separation Optical conductivity Percolation Superconducting phase transition Superconductivity Superfluid density

Convolutional Neural Network-based Architecture for Detecting Face Mask in Crowded Areas

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Convolutional Neural Network-based Architecture for Detectin...

IEEE/SP Workshop on Statistical Signal Processing (SSP)

作者： Jad Abou Chaaya Batoul Zaraket Hassan Harb Ali Mansour Lab-STICC UMR 6285 CNRS ENSTA Bretagne Brest France Applied Physics Lab Faculty of Science Lebanese University Jdeideh Lebanon Department of Computer Science American University of Culture and Education Tyre Lebanon College of Engineering and Technology American University of the Middle East Kuwait

After the invasion of the Covid-19 virus, governments started containing the spread of the virus by forcing people to wear face masks in public places. Therefore, automatic face mask detection has become very important to limit the virus spread. Unfortunately, existing methods present limited performance in accurately detecting masks in crowded areas due to the significant number of faces per scene. In order to tackle this challenge, we propose a two-stage neural network-based architecture that can accurately detect face masks in crowded environments. Several simulations have been conducted to investigate the efficiency of the proposed architecture and the results show a high accuracy of detection that can reach up to 96.5%.

关键词：

A method for time calibration of PET systems using fixed β+ radioactive source

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A method for time calibration of PET systems using fixed β+...

作者： Dulski, K. Silarski, M. Moskal, P. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland

A method for the time calibration of the Time-of-Flight Positron Em-mission Tomograph (TOF-PET) systems using fixed sources is described. Compared to the commercially used calibration methods, the new method gives a chance to run the calibration during the medical scan. Reduction of the time needed for calibration can increase the number of patients examined by PET. The process of calibration of the Jagiellonian Positron Emission Tomograph (J-PET) detector is shown as an example. © 2020 Jagellonian University. All rights reserved.

关键词： Calibration

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

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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