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Application of silicon-polymer composite varistors to protect sensitive medical imaging circuits and performing better voltage bias for SIPMS

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Application of silicon-polymer composite varistors to protec...

作者： Ardebili, F. Tayefi Ghafouri, M. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Department of Physics Shabestar Branch Islamic Azad University Shabestar Iran

Nowadays, Silicon photomultipliers (SiPM) become a reasonable choice for Time-of-Flight Positron Emission Tomography (TOF-PET). To achieve the best performance of SiPMs, it is necessary to adjust a suitable voltage bias. In this article, we are using varistors which protect SiPM from voltage fluctuations. The silicon-polymer composite varistors prepared using hot press method have been investigated. Research on (current-voltage) characteristics of samples shows that by increasing silicon content in the mixture, the breakdown voltage decreases from 110 V to 70 V. The results also show that increasing silicon content decreases the potential barrier height from 0.29 eV to 0.26 eV, however, leakage current increases. Increasing silicon content increases nonlinear coefficient from 4.1 to 4.8. Using these techniques gives us ability to produce suitable surge protector for medical imaging modalities. © 2020 Jagellonian university. All rights reserved.

关键词： Timing circuits

Phase Separation in PCDTBT:PCBM Blends:from Flory-Huggins Interaction Parameters to Ternary Phase Diagrams

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Chinese Journal of Polymer science 2020年第9期38卷 1025-1033,I0009页

作者： Monika Biernat Pawel Dabczynski Pawel Biernat Jakub Rysz Jagiellonian University Faculty of Physics Astronomy and Applied Computer Science ul.lojasiewicza 1130-348 KrakówPoland Mathematisches Institut Rheinische Friedrich-Wilhelms-Universitat BonnEndenicher Allee 6053115 BonnGermany

The substantial increase in the efficiency of organic solar cells achieved in recent years would not have been possible without work on the synthesis of new materials and understanding the relationship between the morphology and performance of organic photovoltaic *** structure of solvent-cast active layers is a result of phase separation in mixtures of donor and acceptor *** a large extent,this process depends on the interactions between the components of the ***,we present a systematic analysis of the morphology of poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)](PCDTBT)and[6,6]-phenyl-C71-butyric acid methyl ester(PC70BM)films in terms of the ternary phase *** interaction parameters between PCDTBT and four different solvents,namely chloroform,chlorobenzene,o-dichlorobenzene,and toluene,were estimated based on swelling *** on these values,ternary phase diagrams of PCDTBT:PC70BM in different solvents were *** morphology of spin-coated films with different blend ratios cast from different solvents is discussed in terms of the obtained phase diagrams.

关键词： PCDTBT Ternary phase diagrams Interaction parameter Swelling

Automated control and optimization of laser-driven ion acceleration

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High Power Laser science and Engineering 2023年第3期11卷 32-40页

作者： B.Loughran M.J.V.Streeter H.Ahmed S.Astbury M.Balcazar M.Borghesi N.Bourgeois C.B.Curry S.J.D.Dann S.DiIorio N.P.Dover T.Dzelzainis O.C.Ettlinger M.Gauthier L.Giuffrida G.D.Glenn S.H.Glenzer J.S.Green R.J.Gray G.S.Hicks C.Hyland V.Istokskaia M.King D.Margarone O.McCusker P.McKenna Z.Najmudin C.Parisuaña P.Parsons C.Spindloe D.R.Symes A.G.R.Thomas F.Treffert N.Xu C.A.J.Palmer School of Mathematics and Physics Queen’s University BelfastBelfastUK Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUK Gérard Mourou Center for Ultrafast Optical Science University of MichiganAnn ArborMIUSA SLAC National Accelerator Laboratory Menlo ParkCAUSA Department of Electrical and Computer Engineering University of AlbertaEdmontonABCanada The John Adams Institute for Accelerator Science Imperial College LondonLondonUK ELI Beamlines Centre Institute of PhysicsCzech Academy of SciencesDolníBˇrežanyCzech Republic Department of Applied Physics Stanford UniversityStanfordCAUSA Department of Physics SUPAUniversity of StrathclydeGlasgowUK Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in PraguePragueCzech Republic Department of Mechanical Engineering Stanford UniversityStanfordCAUSA Institut für Kernphysik Technische Universität DarmstadtDarmstadtGermany

The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter *** limits the utility of sequential 1D scanning of experimental parameters for the optimization of secondary radiation,although to-date this has been the accepted methodology due to low data acquisition *** repetition-rate(HRR)lasers augmented by machine learning present a valuable opportunity for efficient source ***,an automated,HRR-compatible system produced high-fidelity parameter scans,revealing the influence of laser intensity on target pre-heating and proton generation.A closed-loop Bayesian optimization of maximum proton energy,through control of the laser wavefront and target position,produced proton beams with equivalent maximum energy to manually optimized laser pulses but using only 60%of the laser *** demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.

关键词： Bayesian optimization high repetition-rate laser-target interaction laser-driven particle acceleration proton generation

Solution of a problem of thermal stresses in a non-homogeneous thermoelastic infinite medium of isotropic material by finite difference method

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Journal of Ocean Engineering and science 2019年第3期4卷 256-262页

作者： A.M.Farhan A.M.Abd-Alla Moaiad A.Khder Physics Department Faculty of ScienceJazan UniversitySaudi Arabia Physics Department Faculty of ScienceZagzig UniversityEgypt Mathematics Department Faculty of ScienceSohag UniversityEgypt Department of Computer Science Applied Science UniversityBahrain

The present work deals with a new problem of thermoelasticity for an infinitely long and isotropic circular cylinder of temperature dependent physical *** inner and outer curved surfaces of the cylinder are subjected to both the mechanical and thermal boundary conditions.A finite difference model is developed to derive the solution of the problem in which the governing equations are uncoupled linear partial differential *** transient solution at any time can be evaluated directly from the *** order to demonstrate the efficiency of the present model we consider a suitable material and obtain the numerical solution of displacement,temperature,and stresses inside the cylinder for the homogeneous-dependent material properties of the *** results are analyzed with the help of different graphical plots.

关键词： Thermal stress Thermoelasticity Wave propagation Finite difference Method Non-homogeneous medium

Spin fluctuations sufficient to mediate superconductivity in nickelates

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arXiv 2023年

作者： Worm, Paul Wang, Qisi Kitatani, Motoharu Bialo, Izabela Gao, Qiang Ren, Xiaolin Choi, Jaewon Csontosová, Diana Zhou, Ke-Jin Zhou, Xingjiang Zhu, Zhihai Si, Liang Chang, Johan Tomczak, Jan M. Held, Karsten Institute of Solid State Physics TU Wien Vienna1040 Austria Physik-Institut Universität Zürich Winterthurerstrasse 190 ZürichCH-8057 Switzerland Department of Physics The Chinese University of Hong Kong Shatin Hong Kong Department of Material Science University of Hyogo Ako Hyogo678-1297 Japan Wako Saitama351-0198 Japan AGH University of Science and Technology Faculty of Physics and Applied Computer Science Kraków30-059 Poland Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China Diamond Light Source Harwell Campus DidcotOX11 0DE United Kingdom Department of Condensed Matter Physics Faculty of Science Masaryk University Kotlárská 2 Brno611 37 Czech Republic School of Physics Northwest University Xi'An710127 China Department of Physics King's College London Strand LondonWC2R 2LS United Kingdom

Infinite-layer nickelates show high-temperature superconductivity, and the experimental phase diagram agrees well with the one simulated within the dynamical vertex approximation (DΓA). Here, we compare the spin-fluctuation spectrum behind these calculations to resonant inelastic Xray scattering experiments. The overall agreement is good. This independent cross-validation of the strength of spin fluctuations strongly supports the scenario, advanced by DΓA, that spin-fluctuations are the mediator of the superconductivity observed in nickelates. © 2023, CC BY.

关键词： Spin fluctuations

Effective Landé factors for an electrostatically defined quantum point contact in silicene

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arXiv 2021年

作者： Rzeszotarski, Bartlomiej Mreńca-Kolasińska, Alina Peeters, François M. Szafran, Bartlomiej AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 Kraków30-059 Poland Department of Physics National Cheng Kung University Tainan70101 Taiwan Universiteit Antwerpen Departement Fysica Groenenborgerlaan 171 AntwerpenB-2020 Belgium

The transconductance and effective Landé g∗ factors for a quantum point contact defined in silicene by the electric field of a split gate is investigated. The strong spin-orbit coupling in buckled silicene reduces the g∗ factor for in-plane magnetic field from the nominal value 2 to around 1.2 for the first- to 0.45 for the third conduction subband. However, for perpendicular magnetic field we observe an enhancement of g∗ factors for the first subband to 5.8 in nanoribbon with zigzag and to 2.5 with armchair edge. The main contribution to the Zeeman splitting comes from the intrinsic spin-orbit coupling defined by the Kane-Mele form of interaction. Copyright © 2021, The Authors. All rights reserved.

关键词： Silicene

A highly flexible and low-profile metasurface antenna for wearable WBAN systems

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Optik 2024年 313卷

作者： Muhammad, Hevin A. Abdulkarim, Yadgar I. Abdoul, Peshwaz Abdulkareem Awl, Halgurd N. Teksen, Fikret Alpay Alkurt, Fatih O.zkan Karaaslan, Muharrem Bakır, Mehmet Appasani, Bhargav Department of Physics College of Science Charmo University 46023 Chamchamal Kurdistan Region Sulaimani Iraq Electrical and Computer Engineering Department University of Alberta EdmontonABT6G 2R3 Canada Department of Communication Engineering Sulaimani Polytechnic University Sulaimani46001 Iraq Faculty of Engineering and Computer Science Qaiwan International University Kurdistan Region Sulaimani Iraq Department of Electrical-Electronics Engineering Iskenderun Technical University Hatay 31200 Turkey Department of Computer Engineering Yozgat Bozok University Yozgat66200 Turkey School of Electronics Engineering Kalinga Institute of Industrial Technology Bhubaneswar751024 India

Recent years have witnessed the popularity of wearable devices. These devices use Wireless Body Area Networks (WBANs) for healthcare monitoring, personalized tracking, and various other applications. An important component of these devices is the wearable antenna that provides reliable and efficient wireless communication between body-worn sensors and external devices. This paper presents a novel metasurface-based wearable antenna for WBAN applications. By incorporating metasurfaces into the antenna design, achieving enhanced performance is possible. The design was tested using four flexible substrates: wool, paper, fleece, and felt. The paper substrate was chosen because of its superior performance. The dimensions of the antenna are 30 mm x 20 mm, and a 5 ×3 metasurface is used, whose unit cell comprises a square patch. Simulation and experimental results have been performed to measure the radiation pattern, return loss, and gain. A good corroboration is observed between the measured and simulated results. The antenna resonates at three frequencies and offers wide-band resonance characteristics when backed by the metasurface. The peak gain of the antenna without the metasurface was less than 4 dB, but when backed by the metasurface, the peak gain was enhanced to approximately 6 dB. Also, it has been observed that the designed antenna's performance is not significantly affected by the radius of curvature, making it ideal for on-body measurements. This design can inspire further research on low-cost paper substrate-based antennas for WBAN applications. © 2024 Elsevier GmbH

关键词： Wearable antennas

Entanglement properties of optomagnonic crystal from nonlinear perspective

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arXiv 2024年

作者： Wanic, M. Jasiukiewicz, C. Toklikishvili, Z. Jandieri, V. Trybus, M. Jartych, E. Mishra, S.K. Chotorlishvili, L. Department of Physics and Medical Engineering Rzeszów University of Technology Rzeszów35-959 Poland Faculty of Exact and Natural Sciences Tbilisi State University Chavchavadze av.3 Tbilisi0128 Georgia Faculty of Engineering University of Duisburg-Essen CENIDE - Center for Nanointegration Duisburg-Essen DuisburgD-47048 Germany Lublin University of Technology Department of Electronics and Information Technology Faculty of Electrical Engineering and Computer Science Lublin20-618 Poland Varanasi221005 India

Optomagnonics is a new field of research in condensed matter physics and quantum optics focused on strong magnon-photon interactions. Particular interest concerns realistic, experimentally feasible materials and prototype cheap elements for futuristic nanodevices implemented in the processing or storing of quantum information. Hence, magnon-photon entanglement is an essential ingredient since it allows manipulation and control of the quantum states of bipartite systems. Quantifying the entanglement between two continuous bosonic modes, such as magnons and photons, is not trivial. The state-of-the-art for today is the logarithmic negativity, calculated through the quantum Langevin equations subjected to thermal noise. However, due to its complexity, this method requires further approximation. Namely, after the linearization procedure, quantum operators are replaced by their semiclassical expectation values calculated near the steady state. The cost of this approximation is the loss of information about the phases of propagated quantum states. In the present work, we propose a new procedure that avoids the linearization of dynamics. Prior analyzing the quantum entanglement, we explore the nonlinear semiclassical dynamics in detail and precisely define the phase space. The typical nonlinear dynamical system holds bifurcation points and fixed points of different characters in its phase space: Saddle points, Stable and unstable spiral, and Stable node points. Here, we show that methods of the qualitative theory of nonlinear differential equations are also relevant for optomagnonic problems. Our main finding is that entanglement is not defined in the Saddle Point region. On the other hand, the maximum of the entanglement corresponds to the region near the border between the Stable node and Stable spiral regions. Our approach is quite general. However, in numerical calculations, we considered a particular system: optomagnonic crystal based on the yttrium iron garnet (YIG)

关键词： Covariance matrix

Polarization dynamics of solid-state quantum emitters

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arXiv 2023年

作者： Kumar, Anand Samaner, Çağlar Cholsuk, Chanaprom Matthes, Tjorben Paçal, Serkan Oyun, Yağız Zand, Ashkan Chapman, Robert J. Saerens, Grégoire Grange, Rachel Suwanna, Sujin Ateş, Serkan Vogl, Tobias Department of Computer Engineering School of Computation Information and Technology Technical University of Munich Munich80333 Germany Abbe Center of Photonics Institute of Applied Physics Friedrich Schiller University Jena Jena07745 Germany Department of Physics İzmir Institute of Technology İzmir35430 Turkey Department of Photonics İzmir Institute of Technology İzmir35430 Turkey Optical Nanomaterial Group Institute for Quantum Electronics Department of Physics ETH Zurich Zurich8093 Switzerland Optical and Quantum Physics Laboratory Department of Physics Faculty of Science Mahidol University Bangkok10400 Thailand

Quantum emitters in solid-state crystals have recently attracted a lot of attention due to their simple applicability in optical quantum technologies. The polarization of single photons generated by quantum emitters is one of the key parameters that play a crucial role in the applications, such as quantum computation that uses the indistinguishability of photons. However, the degree of single photon polarization is typically quantified using time-averaged photoluminescence intensity of single emitters, which provides limited information about the dipole properties in solids. In this work, we use single defects in hexagonal boron nitride and nanodiamond as efficient room-temperature single photon sources to reveal the origin and the temporal evolution of dipole orientation in solid-state quantum emitters. The angle of excitation and emission dipoles relative to the crystal axes are determined experimentally and then calculated using density functional theory, which results in characteristic angles for every specific defect that can be used as an efficient tool for defect identification and understanding their atomic structure. Moreover, the temporal polarization dynamics reveal a strongly modified linear polarization visibility that depends on the excited state decay time of individual excitation. This effect can be traced back potentially to the excitation of excess charges in the local crystal environment. Understanding such hidden time-dependent mechanisms can further be used to improve the performance of polarization-sensitive experiments, in particular that of quantum communication with single photon emitters. © 2023, CC BY.

关键词： Density functional theory