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Band structure of a nonparabolic two-dimensional electron gas system

Physical Review B 2023年第15期107卷 155139-155139页

作者： Dawid Wutke Mariusz Garb Agnieszka Krawczyk Anna Mielczarek Natalia Olszowska Marcin Rosmus Jacek J. Kolodziej Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 30-348 Kraków Poland National Synchrotron Radiation Centre SOLARIS Jagiellonian University Czerwone Maki 98 PL-30392 Kraków Poland

Using angle-resolved photoelectron spectroscopy (ARPES), we study the band structures of two-dimensional electron gases (2DEGs) formed at Te-doped surfaces of InAs(110), as a result of band bending. The selected surface system is very clean and stable; therefore, ARPES spectra may be registered in short times, with minimal adsorption of residual gases and no photon beam-induced damage. We record a set of data that allows for a detailed analysis of the 2DEG band shapes, their thermal dependencies, and for an assessment of the many-body interactions. We find the electron-phonon interaction extremally weak and the electron-electron interactions hidden in dominant electron-donor interactions. While 2DEG band shapes are observed to be variable in correlation with the 2DEG density, this is tracked down to the variability of the band-bending potential and nonparabolicity of the system, and not to the many-body interactions. Thus, many-body renormalization of the 2DEG bands is not required, and the bands are described well by using the one-electron theoretical frame.

关键词： Electronic structure Two-dimensional electron system Photoemission spectroscopy k dot p method

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Strong emission at 1000 nm from Pr3+/Yb3+-codoped multicomponent tellurite glass

Strong emission at 1000 nm from Pr3+/Yb3+-codoped multicompo...

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作者： Burtan-Gwizdala, Bozena Reben, Manuela Cisowski, Jan Yousef, El Sayed Lisiecki, Radoslaw Nosidlak, Natalia Institute of Physics Cracow University of Technology ul. Podchorazych 1 Cracow30-084 Poland Faculty of Materials Science and Ceramics AGH University of Science and Technology al. Mickiewicza 30 Cracow30-059 Poland Department of Physics Faculty of Sciences King Khalid University P.O. Box 9004 Abha Saudi Arabia Institute of Low Temperatures and Structure Research Polish Academy of Sciences ul. Okolna 2 Wroclaw50-950 Poland

We have investigated the spectroscopic properties of Pr3+-doped and Pr3+/Yb3+-codoped tellurite glass with the molar composition 78TeO2-10Nb2O5-5PbO-1PbF2-5Li2O-1La2O3. Analysis of the absorption data has allowed us to calculate the radiative lifetimes of 3P0 excited state of Pr3+ ions and 2F5/2 excited state of Yb3+ ions as being equal to 9.43 and 440 μs, respectively. These values appear to be much higher than those obtained from the lifetime measurements indicating the presence of various energy transfer mechanisms. This conclusion is supported by analysis of the emission spectra obtained for doped glasses under the 445 nm excitation;the visible spectra consist of only Pr3+ transitions, while the near infrared spectrum of Pr3+/Yb3+-codoped glass demonstrates a strong emission from the 2F5/2 excited state of Yb3+ ion around 1000 nm. This emission is a result of the Pr3+-Yb3+ down-conversion energy transfer and its efficiency for our Pr3+/Yb3+-codoped glass is estimated as 29%. For potential applications, it is important to increase this efficiency and further studies are desirable, in particular, an optimal choice of Pr3+ and Yb3+ concentrations to minimize non-radiative energy transfers among the ions through cross-relaxation and energy migration processes. © 2021 IUPAC & De Gruyter. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. For more information, please visit: http://***/licenses/by-nc-nd/4.0/.

关键词： Ions

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Mrs. Correct and Majority Colorings

arXiv

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arXiv 2022年

作者： Anholcer, Marcin Bosek, Bartlomiej Grytczuk, Jaroslaw Gutowski, Grzegorz Przybylo, Jakub Zając, Mariusz Institute of Informatics and Electronic 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 Science and Technology Faculty of Applied Mathematics al. A. Mickiewicza 30 Kraków30-059 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 *** Codes 05C15 © 2022, CC BY-NC-ND.

关键词： Coloring

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Calcification Alters the Viscoelastic Properties of Tendon Fascicle Bundles Depending on Matrix Content

SSRN

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SSRN 2022年

作者： Dabrowska, Sylwia Ekiert-Radecka, Martyna Karbowniczek, Joanna Weglarz, Wladyslaw P. Heljak, Marcin Lojkowski, Maciej Obuchowicz, Rafal Swieszkowski, Wojciech Mlyniec, Andrzej AGH University of Science and Technology Faculty of Mechanical Engineering and Robotics Krakow Poland AGH University of Science and Technology Faculty of Metals Engineering and Industrial Computer Science Krakow Poland Institute of Nuclear Physics Polish Academy of Sciences Krakow Poland Warsaw University of Technology Faculty of Materials Science and Engineering Warsaw Poland Jagiellonian University Collegium Medicum Department of Radiology Krakow Poland Centre for Advanced Materials and Technologies CEZAMAT Warsaw University of Technology Warsaw Poland

Tendon fascicle bundles are often used as a material for biological grafts in the repair of anterior cruciate ligaments. Tendons intended for biostatic allogenic grafts must meet certain requirements ensuring the appropriate quality of the graft, such as excluding calcifications, which alter the biomechanical properties of soft tissues. In this work, we investigate the influence of early-stage calcification on the mechanical and structural properties of tendon fascicle bundles with varying matrix content. The calcification process was modeled using incubation of the samples in concentrated simulated body fluid. Mechanical and structural properties were investigated using uniaxial tests with relaxation periods and hysteresis, dynamic mechanical analysis, as well as 9.4T magnetic resonance imaging (MRI) and atomic force microscopy (AFM). Mechanical tests showed that the initial phase of calcification causes an increase in the elasticity, storage, and loss modulus, as well as a drop in the normalized value of hysteresis. Further calcification of the samples results in decreased modulus of elasticity and a slight increase in the normalized value of hysteresis. Analysis via MRI and scanning electron microscopy (SEM) showed that incubation alters fibrillar relationships within the tendon structure as well as the flow of body fluids. In the initial stage of calcification, hydroxyapatite crystals are barely visible;however, extending the incubation time for the next 14 days results in the appearance of hydroxyapatite crystals within the tendon structure and leads to damage in its structure. Our results show that the calcification process modifies the collagen-matrix relationships and leads to a change in their mechanical properties. Comparison of results from mechanical tests, SEM, and MRI provides new information regarding the impact of the calcification process on the static and dynamic properties of the tendon, as well as changes in the tendon structure. These findings w

关键词： Bone

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An Overview of Machine Learning Applications in Blockchain for Green Energy Exchanges

An Overview of Machine Learning Applications in Blockchain f...

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Power Engineering Conference (SAUPEC), Southern African Universities

作者： Pfano Nemakonde Fhulufhelo Nemangwele Mukovhe Ratshitanga Dept. of Physics Faculty Science Engineering and Agriculture University of Venda Thohoyandou South Africa Dept. of Electrical Electronic and Computer Engineering Cape Peninsula University of Technology Bellville South Africa

ISBN: (数字)9798331535162

ISBN: (纸本)9798331535179

There is an increasing demand for affordable, decentralised and distributed electricity, which is one of the key motivating factors that has incentivised this review article's writing. Industrial 4.0 has been a conduit through which the conventional grids shift towards a self-autonomous system, and blockchain platforms are emerging as viable solutions to facilitate that paradigm. With the advent of peer-to-peer (P2P) energy trading, community-based energy exchanges have significantly contributed to reduced grid dependency. Machine learning (ML) is being implemented in predictive analytics for energy forecasting (EF), thereby aiding both distribution network operators (DNOs) and aggregators to precisely and predictably monitor, optimise and stabilise grid operations through smart agents. The main aim of this review paper is to provide a detailed analysis of the existing research and implementation approaches on blockchain-based P2P energy trading and a comparative overview of how ML applications aid predictive analytics in community-based energy exchanges.

关键词： Green energy Power engineering Reviews Machine learning Smart grids Peer-to-peer computing Blockchains Predictive analytics Forecasting Monitoring

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High Efficiency and Optically Transparent 2D-MoS2 Heaters for Silicon Photonics

High Efficiency and Optically Transparent 2D-MoS2 Heaters fo...

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Conference on Lasers and Electro-Optics (CLEO)

作者： Dor Oz Nathan Suleymanov Boris Minkovich Vladislav Kostianovskii Liron Gantz Dmitry Polyushkin Thomas Mueller Ilya Goykhman The Faculty of Science and The Center for Nanoscience and Nanotechnology Institute of Applied Physics The Hebrew University of Jerusalem Jerusalem Israel Department of Electrical and Computer Engineering Technion Haifa Israel NVIDIA Israel LTD Yokneam Israel Institute of Photonics Vienna University of Technology Vienna Austria

We experimentally demonstrate the first 1L-MoS2 microheater integrated with a silicon MRR, showing the best-reported power efficiency of ~7.5 mW/n with no significant penalty on insertion loss when placed close to the... 详细信息

ISBN: (纸本)9798350369311

关键词： Optical losses Heating systems Optical resonators Insertion loss Lasers and electrooptics Silicon photonics Electro-optical waveguides

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Initial and final state temperature of in Beam Energy Scan of Au–Au collisions at RHIC energies

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The European Physical Journal Plus 2024年第5期139卷 1-11页

作者： Waqas, Muhammad Ajaz, Muhammad Saidani, Taoufik Haj Ismail, Abd Al Karim School of Mathematics Physics and Optoelectronic Engineering Hubei University of Automotive Technology Shiyan People’s Republic of China Department of Physics Abdul Wali Khan University Mardan Mardan Pakistan Department of Computer Sciences Faculty of Computing and Information Technology Northern Border University Rafha Saudi Arabia Department of Mathematics and Science Ajman University Ajman UAE

To determine the center of mass energy at which ordinary matter undergoes a transition to hot and dense matter, we employed a combination of the blast wave model and Tsallis statistics. Specifically, we analyzed the transverse momentum spectra of resonance particles (in this case, $$K^{*0}$$ ) produced in different centrality intervals during Au–Au collisions at various energies ranging from $$\sqrt{s_{NN}}= 7.7$$ to 39 GeV. Our findings include the phase transition from hadronic matter to the quark-gluon plasma (QGP), and a quick expansion of the system at higher energies and in more central collisions, and disclose the fact that the central collision system, as well as the systems with higher center of mass energies, are easy to be in equilibrium. Our observations indicate a phase transition occurring from ordinary hadronic matter to the quark-gluon plasma (QGP) state in the final stages of collisions but not in the initial stages. Besides, we presented the correlation of $$T_0$$ with various parameters and reported the higher excitation degree of the fireball and its rapid expansion. Our results can provide further insights into the role of the fluctuations in thermal excitation and collective expansion.

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Model Free Deep Deterministic Policy Gradient Controller for Setpoint Tracking of Non-Minimum Phase Systems

Model Free Deep Deterministic Policy Gradient Controller for...

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UKACC International Conference on Control (CONTROL)

作者： Fatemeh Tavakkoli Pouria Sarhadi Benoit Clement Wasif Naeem Faculty of Electrical and Computer Engineering Department Babol Noshirvani University of Technology Babol Iran School of Physics Engineering and Computer Science University of Hertfordshire Hertfordshire UK ENSTA Bretagne CROSSING ILR CNRS 2010 and Flinders University Australia School of Electronics Electrical Engineering and Computer Science Queen's University Belfast UK

ISBN: (数字)9798350374261

ISBN: (纸本)9798350374278

Deep Reinforcement Learning (DRL) techniques have received significant attention in control and decision-making algorithms. Most applications involve complex decision-making systems, justified by the algorithms' computational power and cost. While model-based versions are emerging, model-free DRL approaches are intriguing for their independence from models, yet they remain relatively less explored in terms of performance, particularly in applied control. This study conducts a thorough performance analysis comparing the data-driven DRL paradigm with a classical state feedback controller, both designed based on the same cost (reward) function of the linear quadratic regulator (LQR) problem. Twelve additional performance criteria are introduced to assess the controllers' performance, independent of the LQR problem for which they are designed. Two Deep Deterministic Policy Gradient (DDPG)-based controllers are developed, leveraging DDPG's widespread reputation. These controllers are aimed at addressing a challenging setpoint tracking problem in a Non-Minimum Phase (NMP) system. The performance and robustness of the controllers are assessed in the presence of operational challenges, including disturbance, noise, initial conditions, and model uncertainties. The findings suggest that the DDPG controller demonstrates promising behavior under rigorous test conditions. Nevertheless, further improvements are necessary for the DDPG controller to outperform classical methods in all criteria. While DRL algorithms may excel in complex environments owing to the flexibility in the reward function definition, this paper offers practical insights and a comparison framework specifically designed to evaluate these algorithms within the context of control engineering.

关键词： Training State feedback Uncertainty Costs Computational modeling Decision making Noise

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TOWARDS IMPROVING THE SENSITIVITY OF THE CPT SYMMETRY IN POSITRONIUM DECAYS WITH THE MODULAR J-PET DETECTOR

Acta Physica Polonica B, Proceedings Supplement

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

作者： Chug, N. Gajos, A. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland and Center for Theranostics Jagiellonian University Kraków Poland

The Jagiellonian Positron Emission Tomograph (J-PET) is the first plastic scintillator-based tomographic device used to test discrete symmetries in the charged leptonic sector. One of such tests is for the CPT symmetry, under the combined transformation of charge, parity, and time reversal in the decays of positronium atoms. J-PET performed its first measurement for the CPT symmetry test by searching for non-vanishing CPT-violating angular correlations between the spin and orientation of the decay plane of ortho-positronium (o-Ps) atoms, which is the triplet state of positronium. The sensitivity of testing CPT symmetry with the J-PET detector reaches the precision level of 10−4. Here, we will discuss the prospects of improving the sensitivity of this test beyond the level of 10−4 by enhancing the photon registration efficiency using a new layer of densely packed plastic scintillators and a spherical annihilation chamber as a positronium production medium. © 2022 Jagellonian university. All rights reserved.

关键词： Scintillation counters

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Modification of electrospun PI membranes with active chlorine for antimicrobial skin patches applications

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applied Surface science 2022年 592卷

作者： Sroczyk, Ewa A. Bryant, Jack A. de Cogan, Felicity Knapczyk-Korczak, Joanna Marzec, Mateusz M. Szewczyk, Piotr K. Banzhaf, Manuel Stachewicz, Urszula AGH University of Science and Technology Faculty of Metals Engineering and Industrial Computer Science Cracow30-023 Poland University of Birmingham Institute for Microbiology and Infection B15 2TT Birmingham United Kingdom AGH University of Science and Technology Academic Centre for Materials and Nanotechnology Cracow30-001 Poland

Atopic dermatitis (AD) is a common andcomplex disorder caused by many inherently intractable factors. One of the symptoms is an increased amount of Staphylococcus aureus on the skin surface. These bacteria trigger, accelerate, and exacerbate AD. In order to reduce inflammation, we designed antimicrobial patches, which inhibit bacterial growth. Using electrospinning, we produced polyimide (PI) nanofibers collected in the form of porous membranes. These PI membranes were modified with sodium hypochlorite (NaOCl). The active chlorine content was confirmed with scanning electron microscopy (SEM) with secondary electrons (SE) mode, backscattered electrons (BSE) mode, and energy-dispersive X-ray (EDX) spectroscopy, with Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Moreover, we evaluated the wettability and zeta potential of the patches. Finally, we performed an antimicrobial efficacy assay against the Gram-positive model organism S. aureus and the Gram-negative model, Escherichia coli. We observed that the chlorinated PI patches demonstrate effective bacterial killing, making them excellent material for antimicrobial skin patches applications. © 2022 Elsevier B.V.

关键词： Polyimides

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