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arXiv 2023年

作者： Bialas, P. Burda, Z. Johnston, D.A. Institute of Applied Computer Science Jagiellonian University ul. Lojasiewicza 11 Kraków30-348 Poland AGH University of Krakow Faculty of Physics and Applied Computer Science al. Mickiewicza 30 Kraków30-059 Poland School of Mathematical and Computer Sciences Heriot-Watt University Riccarton EdinburghEH14 4AS United Kingdom

We discuss the distribution of partition function zeros for the grand-canonical ensemble of the zeta-urn model, where tuning a single parameter can give a first or any higher order condensation transition. We compute the locus of zeros for finite-size systems and test scaling relations describing the accumulation of zeros near the critical point against theoretical predictions for both the first and higher order transition regimes. © 2023, CC BY.

关键词： Relativity

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ADVANCEMENTS IN THE STUDIES OF MULTI-PHOTON DECAYS OF ORTHO-POSITRONIUM WITH J-PET

Acta Physica Polonica B, Proceedings Supplement

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Acta Physica Polonica B, Proceedings Supplement 2024年第7期17卷

作者： Tanty, Pooja del Rio, Elena Perez Moskal, Pawel the J-PET Collaboration Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland Centre for Theranostics Jagiellonian University Kraków31-501 Poland

Based on plastic scintillators, Jagiellonian PET (J-PET) is a multidiscipilinary PET scanner having a wide range of applications. With the potential of J-PET to register multiphotons, we aim at exploring the rare and forbidden decay channels of the Positronium triplet state, the ortho-Positronium (o-Ps). The o-Ps decaying into a higher number of photons than the predominant mode (o-Ps → 3γ) is six orders of magnitude smaller than expected from the Quantum Electrodynamics (QED) calculations. In this article, we intend to present the status of the preliminary studies of the multi-photon decays of ortho-Positronium. We will explain toy Monte Carlo simulations involving 4- and 5-gamma decays of the o-Ps, together with a preliminary estimation of a J-PET-like detector efficiencies for these channels. © 2024 Jagiellonian University. All rights reserved.

关键词： Photons

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Effect of Mg Deficiency on the Thermoelectric Properties of Mg2(Si, Sn) Solid Solutions

SSRN

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SSRN 2023年

作者： Byeon, Seokyeong Wiendlocha, Bartlomiej de Boor, Johannes Nielsch, Kornelius Jin, Hyungyu Korea Republic of AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. A. Mickiewicza 30 Krakow30-059 Poland KölnD-51147 Germany Leibniz Institute for Solid State and Materials Science Dresden01069 Germany Institute of Materials Science TU Dresden Dresden01062 Germany Institute of Applied Physics TU Dresden Dresden01062 Germany

Here we report a detailed analysis of the change in the thermoelectric properties of a Mg x (Si, Sn) system under variation of the nominal Mg content x (x = 1.8, 1.9, 2.1, 2.2, 2.3). Additional investigations were carried out to elucidate the mechanism by which Mg-deficient conditions induce point defects such as Mg vacancies and anion anti-site defects, and how these defects govern the thermoelectric properties of a Mg x (Si, Sn) system. We find that unmixing was induced by Mg deficiency, allowing the thermoelectric transport properties of the Mg x (Si, Sn) system to support the band gap reduction of the system. Temperature dependent measurement of the Seebeck coefficient and the Hall coefficient show that Mg-deficiency induces p-type behavior;this is further backed up by an analysis of the transport properties using a single parabolic band (SPB) model at low temperature and a simple two band model at high temperatures. The p-type conduction in the Mg-deficient system suggested that the predominant defects were Mg vacancies. However, the efficiency of p-type doping was much lower (~ 1018 cm-3) than expected when considering only Mg vacancies as origin of charge carriers. . Density functional theory (DFT) calculations suggest the anion anti-site defect on the Mg site as a reason for the low measured carrier concentration and low doping efficiency. Moreover, it is shown that the energy band structure of the Mg deficient Mgx(Si, Sn) system undergoes significant deformation and the formation of an impurity band at the X point as a result of the Mg-deficient conditions, allowing the system to have a relatively anion-rich condition. Furthermore, the Mg deficiency minimize the thermal conductivity with a range of 1 ~ 1.5 W/m∙K at room temperature due to an early bipolar contribution and separated structural phases. The presented study provides a new control parameter that can be utilized to enhance the p-type thermoelectric performance of Mg silicides. © 2023, The Authors

关键词： Phase separation

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Intracellular Uptake of Magnetic Nanocapsules with Ionic Chitosan Shells and Magnetically Triggered Cargo Release

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Nanotechnology, science and applications 2025年 18卷 263-275页

作者： Elżbieta Gumieniczek-Chłopek Joanna Odrobińska-Baliś Adriana Gilarska Gabriela Opiła Manuel Ricardo Ibarra Czesław Kapusta Szczepan Zapotoczny Faculty of Physics and Applied Computer Science AGH University of Krakow Krakow Poland. Jerzy Haber Institute of Catalysis and Surface Chemistry Polish Academy of Sciences Krakow Poland. Faculty of Chemistry Jagiellonian University Krakow Poland. Instituto de Nanociencia Y Materiales de Aragón (INMA) CSIC-Universidad de Zaragoza Laboratorio de Microscopías Avanzadas (LMA) Universidad de Zaragoza Zaragoza Spain.

Introduction:Drug delivery systems typically need to be equipped with targeting moieties in order to be efficiently internalized by cells. Alternatively, magnetic nanoparticles (MNs) combined with active compounds may be driven by magnetic field to the site of action. Delivery of hydrophobic drugs using this approach is challenging as it would require coupling of MNs and hydrophobic environment within nanocarriers and triggering of the drug release. Methods:We propose an approach enabling a magnetically induced forced uptake of core-shell nanocapsules carrying hydrophobic actives together with hydrophobized MNs. Such capsules, formed in a facile emulsification process, are composed of amphiphilic cationic or anionic chitosan (shell) and oil-dispersible MNs (oil core). The capsules were characterized using DLS, cryo-TEM. They were loaded with a model fluorescent dye, Nile Red, and pulled into cells applying a static magnetic field. Then, they were treated with an alternating magnetic field to disrupt the capsules thanks to the action of MNs. Results:Cryo-TEM imaging confirmed the presence of MNs inside the capsules (d≈200 nm). Confocal microscopy imaging showed the efficient capsules' intracellular uptake only after exposition to static magnetic field (some spontaneous uptake was observed for anionic capsules). Then, application of alternating magnetic fields induced rapture of the capsules inside the cells and release of the cargo. Discussion:This approach is very versatile as various lipophilic compounds could be encapsulated, then transported to desired tissues without active or passive targeting and kept there using static magnetic field, limiting undesired side effects of a therapy to the whole organism. The proposed capsules with MNs respond efficiently to magnetic field stimulation - they can be magnetically navigated into the cells and release their cargo after application of alternating magnetic field. This approach opens opportunities for controlled intrace

关键词： drug delivery systems iron oxide nanoparticles magnetic nanoparticles nanocarriers nanomedicine polymer capsules

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Constraining matter bounce scenario from scalar-induced vector perturbations

arXiv

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arXiv 2024年

作者： Zhu, Mian Chen, Chao Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Krakow30-348 Poland Department of Physics School of Science Jiangsu University of Science and Technology Zhenjiang212003 China Jockey Club Institute for Advanced Study The Hong Kong University of Science and Technology Hong Kong

Bouncing cosmologies, while offering a compelling alternative to inflationary models, face challenges from the growth of vector perturbations during the contracting phase. While linear vector instabilities can be avoided with specific initial conditions or the absence of vector degrees of freedom, we demonstrate the significant role of secondary vector perturbations generated by non-linear interactions with scalar fluctuations. Our analysis reveals that in a broad class of single-field matter bounce scenarios, these secondary vector perturbations inevitably get unacceptably large amplitudes, provided the curvature fluctuations are consistent with cosmic microwave background observations. This finding underscores the crucial importance of scalar-induced vector perturbations in bouncing cosmology and highlights the need for further investigation into their potential impact on the viability of these models. © 2024, CC BY.

关键词： Cosmology

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AAK24: Global QCD analysis on polarized parton distribution in the presence of A2 asymmetry measurements

arXiv

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arXiv 2024年

作者： Arbabifar, Fatemeh Tehrani, Shahin Atashbar Khanpour, Hamzeh Department of Physics Education Farhangian University P.O.Box 14665-889 Tehran Iran P.O.Box 19395-5531 Tehran Iran Department of Physics Faculty of Nano and Bio Science and Technology Persian Gulf University Bushehr75169 Iran AGH University Faculty of Physics and Applied Computer Science Al. Mickiewicza 30 Kraków30-055 Poland Department of Physics University of Science and Technology of Mazandaran P.O.Box 48518-78195 Behshahr Iran

This article introduces AAK24, a Next-to-Leading Order (NLO) QCD analysis of polarized data from both polarized Deep Inelastic Scattering (DIS) and Semi-Inclusive Deep Inelastic Scattering (SIDIS) experiments on the nucleon. The AAK24 QCD analysis incorporates SU(2) and SU(3) symmetry breaking, specifically δū ≠ δd¯ ≠ δs¯, while assuming δs¯ and δs are equal. Emphasizing the significance of the semi-inclusive data, the study explores the determination of polarized sea quark distributions. Recent experimental data from JLAB17, COMPASS16, and COMPASS17, including the A2 asymmetry measurements along with SIDIS observables, are thoroughly examined for their impact on the central values of polarized PDFs, their uncertainties, and overall fit quality. Additionally, we include the nonperturbative target mass corrections (TMC) as well as higher-twist terms (HT) which are particularly important. In this work, the uncertainties are quantified using the standard Hessian method. The main results and findings of the AAK24 QCD analysis show overall good agreement with the analyzed experimental data, aligning well with other polarized PDF determinations, particularly DSSV14, LSS10, JAM17, and AKS14, all considering SU(2) and SU(3) symmetry breaking. © 2024, CC BY.

关键词： Polarization

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Resetting induced multimodality

arXiv

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arXiv 2023年

作者： Pogorzelec, Przemyslaw Dybiec, Bartlomiej Doctoral School of Exact and Natural Sciences Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland Institute of Theoretical Physics Mark Kac Center for Complex Systems Research Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland

Properties of stochastic systems are defined by the noise type and deterministic forces acting on the system. In out-of-equilibrium setups, e.g., for motions under action of Lévy noises, the existence of the stationary state is not only determined by the potential but also by the noise. Potential wells need to be steeper than parabolic in order to assure existence of stationary states. The existence of stationary states, in sub-harmonic potential wells, can be restored by stochastic resetting, which is the protocol of starting over at random times. Herein we demonstrate that the combined action of Lévy noise and Poissonian stochastic resetting can result in the phase transition between non-equilibrium stationary states of various multimodality in the overdamped system in super-harmonic potentials. Fine-tuned resetting rates can increase the modality of stationary states, while for high resetting rates the multimodality is destroyed as the stochastic resetting limits the spread of particles. © 2023, CC BY.

关键词： Stochastic systems

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Multilayer CVD graphene electrodes using a transfer-free process for the next generation of optically transparent and MRI-compatible neural interfaces

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Microsystems & Nanoengineering 2022年第5期8卷 183-196页

作者： Nasim Bakhshaee Babaroud Merlin Palmar Andrada Iulia Velea Chiara Coletti Sebastian Weingärtner Frans Vos Wouter A.Serdijn Sten Vollebregt Vasiliki Giagka Department of Microelectronics Faculty of Electrical EngineeringMathematics and Computer ScienceDelft University of TechnologyMekelweg 4Delft 2628 CDThe Netherlands Technologies for Bioelectronics Group Department of System Integration and Interconnection TechnologiesFraunhofer Institute for Reliability and Micro-integration IZMGustav-Meyer-Allee 25Berlin 13355Germany Department of Imaging Physics Faculty of Applied ScienceDelft University of TechnologyLorentzweg 1Delft 2628 CJThe Netherlands Erasmus University Medical Center(Erasmus MC) dr.Molewaterplein 40Rotterdam 3015 GDThe Netherlands

Multimodal platforms combining electrical neural recording and stimulation,optogenetics,optical imaging,and magnetic resonance(MRI)imaging are emerging as a promising platform to enhance the depth of characterization in neuroscientific *** conductive,optically transparent,and MRI-compatible electrodes can optimally combine all *** as a suitable electrode candidate material can be grown via chemical vapor deposition(CVD)processes and sandwiched between transparent biocompatible ***,due to the high graphene growth temperature(≥900℃)and the presence of polymers,fabrication is commonly based on a manual transfer process of pre-grown graphene sheets,which causes reliability *** this paper,we present CVD-based multilayer graphene electrodes fabricated using a wafer-scale transfer-free process for use in optically transparent and MRI-compatible neural *** fabricated electrodes feature very low impedances which are comparable to those of noble metal electrodes of the same size and *** also exhibit the highest charge storage capacity(CSC)reported to date among all previously fabricated CVD graphene *** graphene electrodes did not reveal any photo-induced artifact during 10-Hz light pulse ***,we show here,for the first time,that CVD graphene electrodes do not cause any image artifact in a 3T MRI *** results demonstrate that multilayer graphene electrodes are excellent candidates for the next generation of neural interfaces and can substitute the standard conventional metal *** fabricated graphene electrodes enable multimodal neural recording,electrical and optogenetic stimulation,while allowing for optical imaging,as well as,artifact-free MRI studies.

关键词： transparent transfer process

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An improved KNN algorithm based on ensemble methods and correlation

An improved KNN algorithm based on ensemble methods and corr...

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International Conference on Information science and Technology (ICIST)

作者： Youness Manzali Khalidou Abdoulaye Barry Mohamed El Far Applied Physics Computer Science and Statistics Laboratory Faculty of Sciences Dhar El Mahraz Sidi Mohammed Ben Abdellah University Fez Morocco

K-Nearest Neighbors is a widely used algorithm due to its simplicity and efficacity. However, KNN suffers from many drawbacks, such as it does not work well with datasets with a high number of features. Also, not all the features contribute to the classification process. To resolve these issues, we present an improved KNN algorithm which uses KNN as a base learner in an ensemble method and correlation for selecting the features subsets. The experiment results show that the proposed algorithm performed better than other machine learning algorithms.

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DFDFTr + RAC-DAC: Dense Fusion with Deep Fusion Transformer and Realistic Actor-Critic combined with Decoupled Actor-Critic for end-to-end continuous multi-task robotic arm control

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Expert Systems with Applications 2025年 276卷

作者： Dang, Thi Phuc Nguyen, Truong Chinh Dau, Sy Hieu Department of Computer Science Faculty of Information Technology Industrial University of Ho Chi Minh City 12 Nguyen Van Bao Ho Chi Minh7000 Viet Nam Department of Applied Physics Faculty of Applied Science University of Technology - Viet Nam National University HCMC Ho Chi Minh City To Hien Thanh Ho Chi Minh7000 Viet Nam

In this paper, we propose novel methods to address the challenges of intelligent robotic arm operations in complex environments. Our approach includes a deep learning method for 6D object pose estimation and a deep reinforcement learning method for controlling complex tasks. For 6D object pose estimation, we introduce the Dense Fusion combined with Deep Fusion Transformer model (DFDFTr). This method integrates Dense Fusion and Deep Fusion Transformer, applies re-parameterization techniques such as Reparameterized Convolution and Batch Normalization Fusion, and incorporates specialized neural networks for each stage of the model. Experimental results on the LineMOD and Occlusion LineMOD datasets demonstrate that our method outperforms one-stage approaches like DenseFusion and MPF6D in accuracy and achieves results comparable to advanced two-stage methods such as PVN3D and DTr. Leveraging re-parameterization, our method maintains competitive inference speed with significantly fewer parameters than PVN3D and MPF6D, PoseCNN+ICP without sacrificing accuracy. Additionally, it efficiently processes multiple objects, handling 8 objects in 0.1 s compared to 0.07 s for a single object. For continuous task control, we propose a deep reinforcement learning approach using Realistic Actor-Critic combined with Decoupled Actor-Critic (RAC-DAC), integrated with techniques such as Relay Hindsight Experience Replay (RHER), Multi-step Hindsight Experience Replay (MHER), Curiosity-Driven Prioritization (CDP), and Projected Conflicting Gradients (PCGrad). Experimental results show that RAC-DAC-RHER achieves significantly higher success rates than DDPG-RHER and TD3-RHER, particularly in challenging tasks such as object grasping. It also ensures efficient learning and high accuracy. Furthermore, by refining hyperparameters and integrating MHER, CDP, PCGrad, MLP, and the Clipping Mechanism, we enhanced learning performance, mitigated instabilities, and enabled higher learning rates in spars

关键词： Robotic arms

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