检索结果-内蒙古大学图书馆

An on-chip platform for multi-degree-of-freedom control of two-dimensional quantum and nonlinear materials

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Tang, Haoning Wang, Yiting Ni, Xueqi Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo Fan, Shanhui Mazur, Eric Yacoby, Amir Cao, Yuan School of Engineering and Applied Sciences Harvard University CambridgeMA02138 United States National Institute for Materials Science Namiki 1-1 Ibaraki Tsukuba305-0044 Japan Department of Physics Massachusetts Institute of Technology CambridgeMA02139 United States Department of Applied Physics Ginzton Laboratory Stanford University StanfordCA94305 United States Department of Physics Faculty of Art and Sciences Harvard University CambridgeMA02138 United States Society of Fellows Harvard University CambridgeMA02138 United States Department of Electrical Engineering and Computer Science University of California at Berkeley BerkeleyCA94720 United States

Two-dimensional materials (2DM) and their derived heterostructures have electrical and optical properties that are widely tunable via several approaches, most notably electrostatic gating and interfacial engineering such as twisting. While electrostatic gating is inherently simple and has thus been ubiquitously employed on 2DM, being able to tailor the interfacial properties in a similar real-time manner represents the next leap in our ability to modulate the underlying physics and build exotic quantum devices with 2DM1–6. However, all existing approaches rely on external machinery such as scanning microscopes, which often limit their scope of applications, and there is currently no means of tuning a 2D interface that has the same accessibility and scalability as device-level electrostatic gating. Here, we demonstrate the first on-chip platform designed for 2D materials with in situ tunable interfacial properties, utilizing a microelectromechanical system (MEMS). Each of these compact, cost-effective, and versatile devices is a standalone micromachine that allows voltage-controlled approaching, twisting, and pressurizing of two sheets of 2DM with high accuracy. As a demonstration, we engineer various flavours of synthetic topological singularities, known as half-skyrmions or merons, in the nonlinear optical susceptibility of twisted hexagonal boron nitride (h-BN)7–10, via simultaneous control of twist angle and interlayer separation. The chirality of the resulting moiré pattern further induces a strong circular dichroism in the second-harmonic generation. A potential application of this topological nonlinear susceptibility is to create integrated light sources that have widely and real-time tunable polarization, which we demonstrate experimentally. As a perspective, a quantum version of the same principle can generate entangled photon pairs with tunable entanglement characteristics. Our invention pushes the boundary of currently available technologies for manipulati

关键词： III-V semiconductors

MULTILINGUAL TRANSFORMERS FOR PRODUCT MATCHING - EXPERIMENTS AND A NEW BENCHMARK IN POLISH

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Możdżonek, Michal Wróblewska, Anna Tkachuk, Sergiy Lukasik, Szymon Facult of Mathematics and Information Science Warsaw Universit of Technolo Warsaw Poland Systems Research Institute Polish Academy of Sciences ul. Newelska 6 Warsaw01-447 Poland Faculty of Physics and Applied Computer Science AGH University of Science and Technology al Mickiewicza 30 Kraków30-059 Poland

Product matching corresponds to the task of matching identical products across different data sources. It typically employs available product features which, apart from being multimodal, i.e., comprised of various data types, might be non-homogeneous and incomplete. The paper shows that pre-trained, multilingual Transformer models, after fine-tuning, are suitable for solving the product matching problem using textual features both in English and Polish languages. We tested multilingual mBERT and XLM-RoBERTa models in English on Web Data Commons - training dataset and gold standard for large-scale product matching. The obtained results show that these models perform similarly to the latest solutions tested on this set, and in some cases, the results were even better. Additionally, we prepared a new dataset - *** - that is entirely in Polish and based on offers in selected categories obtained from several online stores for the research purpose. It is the first open dataset for product matching tasks in Polish, which allows comparing the effectiveness of the pre-trained models. Thus, we also showed the baseline results obtained by the fine-tuned mBERT and XLM-RoBERTa models on the Polish datasets. Copyright © 2022, The Authors. All rights reserved.

关键词： Electronic commerce

Comparative studies of the sensitivities of sparse and full geometries of Total-Body PET scanners built from crystals and plastic scintillators

学校读者我要写书评

暂无评论

arXiv 2023年

作者： Dadgar, Meysam Parzych, Szymon Baran, Jakub Chug, Neha Curceanu, Catalina Czerwiński, Eryk Dulski, Kamil Elyan, Kavya Gajos, Aleksander Hiesmayr, Beatrix C. Kaplon, Lukasz Klimaszewski, Konrad Konieczka, Pawel Korcyl, Grzegorz Kozik, Tomasz Krzemień, Wojciech Kumar, Deepak Niedźwiecki, Szymon Panek, Domonik del Rio, Eleną Perez Raczyński, Lech Sharma, Sushil Shivani Shopa, Roman Y. Skurzok, Magdalena Stępień, Ewa L. Ardebili, Faranak Tayefi Ardebili, Keyvan Tayefi Vandenberghe, Stefaan Wiślicki, Wojciech Moskal, Pawel Faculty of Physics Astronomy and Applied Computer Science Poland Department of Experimental Particle Physics and Applications Jagiellonian University Krakow Poland Total-Body Jagiellonian-PET Laboratory Jagiellonian University Krakow Poland Theranostics Center Jagiellonian University Krakow Poland INFN Laboratori Nazionali di Frascati Frascati Italy Faculty of Physics University of Vienna Vienna Austria Department of Complex Systems National Centre for Nuclear Research Otwock-Swierk Poland High Energy Physics Division National Centre for Nuclear Research Otwock-Swierk Poland Department of Electronics and Information Systems MEDISIP Ghent University-IBiTech Gent Belgium

Background: Alongside the benefits of Total-Body imaging modalities, such as higher sensitivity, single-bed position, low dose imaging, etc., their final construction cost prevents worldwide utilization. The main aim of this study is to present a simulation-based comparison of the sensitivities of existing and currently developed tomographs to introduce a cost-efficient solution for constructing a Total-Body PET scanner based on plastic scintillators. Methods: For the case of this study, eight tomographs based on the uEXPLORER configuration with different scintillator materials (BGO, LYSO), axial field-of-view (97.4 cm and 194.8 cm), and detector configuration (full and sparse) were simulated. In addition, 8 J-PET scanners with different configurations, such as various axial field-of-view (200 cm and 250 cm), the different cross-sections of plastic scintillator, and the multiple numbers of the plastic scintillator layers (2, 3, and 4), based on J-PET technology have been simulated by GATE software. Furthermore, Biograph Vision has been simulated to compare the results with standard PET scans. Two types of simulations have been performed. The first one with a centrally located source with a diameter of 1mm and a length of 250 cm, and the second one with the same source inside a water-filled cylindrical phantom with a diameter of 20 cm and a length of 183 cm. Results: With regards to sensitivity, among all the proposed scanners, the ones constructed with BGO crystals give the best performance (∼ 350 cps/kBq at the center). The utilization of sparse geometry or LYSO crystals significantly lowers the achievable sensitivity of such systems. The J-PET design gives a similar sensitivity to the sparse LYSO crystal-based detectors while having full detector coverage over the body. Moreover, it provides uniform sensitivity over the body with additional gain on its sides and provides the possibility for high-quality brain imaging. Conclusion: Taking into account not only the s

关键词： Ionization

Positronium Lifetime Imaging with the Biograph Vision Quadra using 124I

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Mercolli, Lorenzo Steinberger, William M. Rathod, Narendra Conti, Maurizio Moskal, Pawel Rominger, Axel Seifert, Robert Shi, Kuangyu Stępień, Ewa L. Sari, Hasan Department of Nuclear Medicine Inselspital Bern University Hostpital University of Bern Bern Switzerland ARTORG Center for Biomedical Engineering Research University of Bern Bern Switzerland Siemens Medical Solutions USA Inc. KnoxvilleTN United States Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Krakow Poland Centre for Theranostics Jagiellonian University Krakow Poland Siemens Healthineers International AG Zürich Switzerland

Purpose: Measuring the ortho-positronium (oPs) lifetime in human tissue bears the potential of adding clinically relevant information about the tissue microenvironment to conventional positron emission tomography (PET). Through phantom measurements, we investigate the voxel-wise measurement of oPs lifetime using a commercial long-axial field-of-view (LAFOV) PET scanner. Methods: We prepared four samples with mixtures of Amberlite XAD4, a porous polymeric adsorbent, and water and added between 1.12 MBq and 1.44 MBq of 124I. The samples were scanned in two different setups: once with a couple of centimeters between each sample (15 minutes scan time) and once with all samples taped together (40 minutes scan time). For each scan, we determine the oPs lifetime for the full samples and at the voxel level. The voxel sizes under consideration are 10.03 mm3, 7.13 mm3 and 4.03 mm3. Results: Amberlite XAD4 allows the preparation of samples with distinct oPs lifetime. Using a Bayesian fitting procedure, the oPs lifetimes in the whole samples are 2.52±0.03 ns, 2.37±0.03 ns, 2.27±0.04 ns and 1.82±0.02 ns, respectively. The voxel-wise oPs lifetime fits showed that even with 4.03 mm3 voxels the samples are clearly distinguishable and a central voxels have good count statistics. However, the situation with the samples close together remains challenging with respect to the spatial distinction of regions with different oPs lifetimes. Conclusion: Our study shows that positronium lifetime imaging on a commercial LAFOV PET/CT should be feasible under clinical conditions using 124I. © 2025, CC BY.

关键词： Tissue

Uninorm-like parametric activation functions for human-understandable neural models

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Csiszár, Orsolya Pusztaházi, Luca Sára Dénes-Fazakas, Lehel Gashler, Michael S. Kreinovich, Vladik Csiszár, Gábor Faculty of Electrical Engineering and Computer Science Aalen University Aalen Germany Physiological Controls Research Center Óbuda University Budapest Hungary Department of Computer Science University of Texas at El Paso El PasoTX79968 United States SupplyPike FayettevilleAR72703 United States Institute of Materials Physics University of Stuttgart Stuttgart Germany Applied Informatics and Applied Mathematics Doctoral School Óbuda University Budapest Hungary John von Neumann Faculty of Informatics Óbuda University Budapest Hungary

We present a deep learning model for finding human-understandable connections between input features. Our approach uses a parameterized, differentiable activation function, based on the theoretical background of nilpotent fuzzy logic and multi-criteria decision-making (MCDM). The learnable parameter has a semantic meaning indicating the level of compensation between input features. The neural network determines the parameters using gradient descent to find human-understandable relationships between input features. We demonstrate the utility and effectiveness of the model by successfully applying it to classification problems from the UCI Machine Learning Repository. © 2022, CC BY-NC-ND.

关键词： Chemical activation

Valley-Polarized Quantum Hall Phase in a Strain-Controlled Dirac System

学校读者我要写书评

暂无评论

Physical Review Letters 2024年第16期132卷 166601-166601页

作者： G. Krizman J. Bermejo-Ortiz T. Zakusylo M. Hajlaoui T. Takashiro M. Rosmus N. Olszowska J. J. Kołodziej G. Bauer Y. Guldner G. Springholz L.-A. de Vaulchier Institut für Halbleiter und Festkörperphysik Johannes Kepler Universität Altenberger Strasse 69 4040 Linz Austria Laboratoire de Physique de l’Ecole normale supérieure ENS Université PSL CNRS Sorbonne Université 24 rue Lhomond 75005 Paris France National Synchrotron Radiation Centre SOLARIS Jagiellonian University Czerwone Maki 98 30-392 Krakow Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University 30-348 Krakow Poland

In multivalley systems, the valley pseudospin offers rich physics going from encoding of information by its polarization (valleytronics), to exploring novel phases of matter when its degeneracy is changed. Here, by strain engineering, we reveal fully valley-polarized quantum Hall phases in the Pb1−xSnxSe Dirac system. Remarkably, when the valley energy splitting exceeds the fundamental band gap, we observe a “bipolar quantum Hall phase,” heralded by the coexistence of hole and electron chiral edge states at distinct valleys in the same quantum well. This suggests that spatially overlaid counterpropagating chiral edge states emerging at different valleys do not interfere with each other.

关键词： Edge states Integer quantum Hall effect Magneto-optics Magnetotransport Topological materials Valley degrees of freedom Valleytronics

Controllable magnetic anisotropy and spin orientation of a prototypical easy-plane antiferromagnet on a ferromagnetic support

学校读者我要写书评

暂无评论

Physical Review B 2021年第13期104卷 134434-134434页

作者： M. Ślęzak H. Nayyef P. Dróżdż W. Janus A. Kozioł-Rachwał M. Szpytma M. Zając T. O. Menteş F. Genuzio A. Locatelli T. Ślęzak AGH University of Science and Technology Faculty of Physics and Applied Computer Science Kraków Poland National Synchrotron Radiation Centre SOLARIS Jagiellonian University Kraków Poland Elettra - Sincrotrone Trieste Basovizza Trieste Italy CERIC-ERIC Basovizza Trieste Italy

We report the magnetic properties of easy-plane antiferromagnetic NiO(111) thin films epitaxially grown on ferromagnetic Fe(110) layers. We find that the magnetic moments in NiO are rotatable within the NiO(111) sample plane and both magnetic anisotropy and orientation of antiferromagnetic NiO spins are determined by the magnetic properties of underlying ferromagnetic Fe layer. Specifically, the magnetic state and anisotropy of antiferromagnetic NiO can be modified by tuning the thickness of Fe, changing the temperature, or applying small external magnetic field.

关键词： Crystal phenomena Magnetic anisotropy Magnetic interactions Magnetic order Magnetic phase transitions Methods in magnetism Antiferromagnets Crystal structures Ferromagnets Magnetic insulators Magnetic multilayers Surfaces Thin films Electron diffraction Epitaxy Evaporation Kerr effect Magnetization measurements X-ray absorption spectroscopy X-ray magnetic circular dichroism X-ray magnetic linear dichroism X-ray photoemission electron microscopy

Factorial cumulants from global baryon number conservation

学校读者我要写书评

暂无评论

Physical Review C 2020年第6期102卷 064908-064908页

作者： Michał Barej Adam Bzdak AGH University of Science and Technology Faculty of Physics and Applied Computer Science 30-059 Kraków Poland

The proton, antiproton, and mixed proton-antiproton factorial cumulants originating from the global conservation of baryon number are calculated analytically up to the sixth order. Our results can be directly tested i... 详细信息

关键词： Particle correlations & fluctuations Relativistic heavy-ion collisions

Text-Based Product Matching with Incomplete and Inconsistent Items Descriptions 21st

学校读者我要写书评

暂无评论

Text-Based Product Matching with Incomplete and Inconsisten...

21st International Conference on Computational science, ICCS 2021

作者： Lukasik, Szymon Michalowski, Andrzej Kowalski, Piotr A. Gandomi, Amir H. Faculty of Physics and Applied Computer Science AGH University of Science and Technology al. Mickiewicza 30 Kraków30-059 Poland Systems Research Institute Polish Academy of Sciences ul. Newelska 6 Warsaw01-447 Poland Synerise PLC ul. Lubostroń 1 Kraków30-383 Poland Faculty of Engineering and Information Technology University of Technology Sydney UltimoNSW2007 Australia

ISBN: (纸本)9783030779634

In recent years Machine Learning and Artificial Intelligence are reshaping the landscape of e-commerce and retail. Using advanced analytics, behavioral modeling, and inference, representatives of these industries can leverage collected data and increase their market performance. To perform assortment optimization – one of the most fundamentals problems in retail – one has to identify products that are present in the competitors’ portfolios. It is not possible without effective product matching. The paper deals with finding identical products in the offer of different retailers. The task is performed using a text-mining approach, assuming that the data may contain incomplete information. Besides the description of the algorithm, the results for real-world data fetched from the offers of two consumer electronics retailers are being demonstrated. © 2021, Springer Nature Switzerland AG.

关键词： Sales