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SSRN 2022年

作者： Gong, Helin Cheng, Sibo Chen, Zhang Li, Qing Quilodrán-Casas, César Xiao, Dunhui Arcucci, Rossella SJTU-ParisTech Elite Institute of Technology Shanghai 200240 China Data Science Institute Imperial College London LondonSW7 2AZ United Kingdom Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Faculty of Sciences and Engineering Swansea University SwanseaSA1 8EN United Kingdom Department of Earth Science & Engineering Imperial College London LondonSW7 2AZ United Kingdom

This paper proposes an approach that combines reduced-order models with machine learning in order to create an digital twin to predict the power distribution over the core during the operation stage. The operational digital twin is designed to solve forward problems given input operation parameters, as well as to solve inverse problems given some observations of the power field. The forward model is realised using SVD autoencoder reduced order model and machine learning methods. The inverse model is based on a generalised latent assimilation method. The effectiveness in the sense of accuracy and real-time solver of the digital twin is illustrated through a real engineering problem in nuclear reactor physics - reactor core simulation in the life cycle of HPR1000 affected by control rod inserting step, burnup, power level and inlet temperature of the coolant, which shows potential applications for on-line monitoring purpose. © 2022, The Authors. All rights reserved.

关键词： Inverse problems

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Observation of Reverse Saturable Absorption of an X-ray Laser

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Physical Review Letters 2017年第7期119卷 075002-075002页

作者： B. I. Cho M. S. Cho M. Kim H.-K. Chung B. Barbrel K. Engelhorn T. Burian J. Chalupský O. Ciricosta G. L. Dakovski V. Hájková M. Holmes L. Juha J. Krzywinski R. W. Lee Chang Hee Nam D. S. Rackstraw S. Toleikis J. J. Turner S. M. Vinko J. S. Wark U. Zastrau P. A. Heimann Center for Relativistic Laser Science Institute for Basic Science (IBS) Gwangju 61005 Korea Department of Physics and Photon Science Gwangju Institute of Science and Technology Gwangju 61005 Korea Atomic and Molecular Data Unit Nuclear Data Section IAEA P.O. Box 100 A-1400 Vienna Austria Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Institute of Physics ASCR Na Slovance 2 18221 Prague 8 Czech Republic Department of Physics Clarendon Laboratory University of Oxford Parks Road Oxford OX1 3PU United Kingdom SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park California 94025 USA Department of Physics University of California Berkeley California 94720 USA Deutsches-Elektronensynchrotron DESY Notkestrasse 85 D-22603 Hamburg Germany European XFEL Holzkoppel 4 22869 Schenefeld Germany

A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 1016 –1017 W/cm2. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray free-electron laser pulses.

关键词： High-energy-density plasmas Laser light absorption in plasmas Multiphoton or tunneling ionization & excitation Plasma production & heating by laser beams, laser-foil, laser-cluster X-ray beams & optics Hot dense plasma

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Physics-informed Neural Network for system identification of rotors ⁎

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IFAC-PapersOnLine 2024年第15期58卷 307-312页

作者： Xue Liu Wei Cheng Ji Xing Xuefeng Chen Zhibin Zhao Rongyong Zhang Qian Huang Jinqi Lu Hongpeng Zhou Wei Xing Zheng Wei Pan The National Key Laboratory of Aerospace Power System and Plasma Technology and School of Mechanical Engineering Xi’an Jiaotong University Xi’an China China Nuclear Power Engineering Co. Ltd. Beijing China Shanghai Apollo Machinery Co. Ltd. Shanghai China Department of Computer Science University of Manchester Manchester United Kingdom School of Computer Data and Mathematical Sciences Western Sydney University Sydney Australia

The condition of the rotor system remains difficult to assess due to system nonlinearity and nosiy measurements. To deal with the problem, we proposed a hierarchical physics-informed neural network (HPINN) to discover the ordinary differential equation (ODE) of a healthy/faulty rotor system from noise measurements and then assess the machine condition based on the discovered ODE. Specifically, the ODE of a healthy rotor system is first stably identified from noise measurement through HPINN guided by rotor dynamics. Based on the identified healthy ODE, the extra fault terms in the ODE of the faulty rotor system are then sparsely regressed from the predefined library embedded in HPINN. Moreover, with the mathematical terms of discovered fault, the potential fault and the health indicator (HI) are diagnosed and constructed to assess the condition of the rotor system, respectively. Finally, the effectiveness of the proposed method is verified by the data set collected on the circulating water test bench, showing the potential for practical applications.

关键词： rotor system fault diagnosis health indicator physics-informed neural network

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Estimating geographic variation of infection fatality ratios during epidemics

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Infectious Disease Modelling 2024年第2期9卷 634-643页

作者： Joshua Ladau Eoin L.Brodie Nicola Falco Ishan Bansal Elijah B.Hoffman Marcin P.Joachimiak Ana M.Mora Angelica M.Walker Haruko M.Wainwright Yulun Wu Mirko Pavicic Daniel Jacobson Matthias Hess James B.Brown Katrina Abuabara Departments of Computational Precision Health and Dermatology University of CaliforniaSan FranciscoCA94115USA Arva Intelligence Inc.Salt Lake CityUT84101USA Computational Biosciences Group Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Earth and Environmental Sciences Area Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Graduate Group in Biostatistics University of CaliforniaBerkeleyCA94720USA Biosystems Data Science Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCA94720USA Center for Environmental Research and Community Health(CERCH) School of Public HealthUniversity of CaliforniaBerkeleyCA94720USA Bredesen Center for Interdisciplinary Research and Graduate Education University of TennesseeKnoxvilleTN37996USA Department of Nuclear Science and Engineering Massachusetts Institute of TechnologyBostonMA02139USA Biosciences Oak Ridge National LaboratoryOak RidgeTN37830USA University of California DavisCA95616USA Statistics Department University of CaliforniaBerkeleyCA94720USA Division of Epidemiology and Biostatistics University of California Berkeley School of Public Health2121 Berkeley WayBerkeleyCA94720USA

Objectives We aim to estimate geographic variability in total numbers of infections and infection fatality ratios(IFR;the number of deaths caused by an infection per 1,000 infected people)when the availability and quality of data on disease burden are limited during an *** We develop a noncentral hypergeometric framework that accounts for differential probabilities of positive tests and reflects the fact that symptomatic people are more likely to seek *** demonstrate the robustness,accuracy,and precision of this framework,and apply it to the United States(U.S.)COVID-19 pandemic to estimate county-level SARS-CoV-2 *** The estimators for the numbers of infections and IFRs showed high accuracy and precision;for instance,when applied to simulated validation data sets,across counties,Pearson correlation coefficients between estimator means and true values were 0.996 and 0.928,respectively,and they showed strong robustness to model *** the county-level estimators to the real,unsimulated COVID-19 data spanning April 1,2020 to September 30,2020 from across the U.S.,we found that IFRs varied from 0 to 44.69,with a standard deviation of 3.55 and a median of *** The proposed estimation framework can be used to identify geographic variation in IFRs across settings.

关键词： Infection fatality ratio Infection fatality rate Noncentral hypergeometric distribution COVID-19 SARS-CoV-2

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Light atom quantum oscillations in UC and US

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Physical Review B 2016年第1期93卷 014306-014306页

作者： Yuen Yiu A. A. Aczel G. E. Granroth D. L. Abernathy M. B. Stone W. J. L. Buyers J. Y. Y. Lin G. D. Samolyuk G. M. Stocks S. E. Nagler Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA Quantum Condensed Matter Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Neutron Data Analysis and Visualization Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Canadian Neutron Beam Centre Canadian Nuclear Laboratories Chalk River Ontario Canada K0J 1J0 California Institute of Technology Pasadena California 91125 USA Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA

High-energy vibrational scattering in the binary systems UC and US is measured using time-of-flight inelastic neutron scattering. A clear set of well-defined peaks equally separated in energy is observed in UC, corresponding to harmonic oscillations of the light C atoms in a cage of heavy U atoms. The scattering is much weaker in US and only a few oscillator peaks are visible. We show how the difference between the materials can be understood by considering the neutron scattering lengths and masses of the lighter atoms. Monte Carlo ray tracing is used to simulate the scattering, with near quantitative agreement with the data in UC, and some differences with US. The possibility of observing anharmonicity and anisotropy in the potentials of the light atoms is investigated in UC. Overall, the observed data is well accounted for by considering each light atom as a single atom isotropic quantum harmonic oscillator.

关键词： Phonons Inelastic neutron scattering Monte Carlo methods

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Quantum Advantage in Cryptography with a Low-Connectivity Quantum Annealer

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Physical Review Applied 2020年第5期13卷 054062-054062页

作者： Feng Hu Lucas Lamata Chao Wang Xi Chen Enrique Solano Mikel Sanz Key Laboratory of Specialty Fiber Optics and Optical Access Networks Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication Shanghai Institute for Advanced Communication and Data Science Shanghai University Shanghai 200444 China Department of Physical Chemistry University of the Basque Country UPV/EHU Apartado 644 48080 Bilbao Spain Departamento de Física Atómica Molecular y Nuclear Universidad de Sevilla Sevilla 41080 Spain International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics Shanghai University Shanghai 200444 China IKERBASQUE Basque Foundation for Science María Díaz de Haro 3 Bilbao 48013 Spain IQM Munich Germany

The application in cryptography of quantum algorithms for prime factorization fostered the interest in quantum computing. However, quantum computers, and particularly quantum annealers, can also be helpful to construct secure cryptographic keys. Indeed, finding robust Boolean functions for cryptography is an important problem in sequence ciphers, block ciphers, and hash functions, among others. Due to the superexponential size O(22n) of the associated space, finding n-variable Boolean functions with global cryptographic constraints is computationally hard. This problem has already been addressed employing generic low-connected incoherent D-Wave quantum annealers. However, the limited connectivity of the Chimera graph, together with the exponential growth in the complexity of the Boolean-function design problem, limit the problem scalability. Here, we propose a special-purpose coherent quantum-annealing architecture with three couplers per qubit, designed to optimally encode the bent-function design problem. A coherent quantum annealer with this tree-type architecture has the potential to solve the eight-variable bent-function design problem, which is classically unsolved, with only 127 physical qubits and 126 couplers. This paves the way to reach useful quantum supremacy within the framework of quantum annealing for cryptographic purposes.

关键词： Adiabatic quantum optimization Boolean satisfiability problem Quantum algorithms Quantum cryptography Quantum simulation Ising model

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Corrigendum to “Measurement of the 134 Xe(n, 2n) 133m,g Xe and 136 Xe(n, 2n) 135m,g Xe reaction cross-sections and isomeric ratios induced by the 14.8 MeV neutrons” [Appl. Radiat. Isot. 200 (2023) 110948]

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Applied Radiation and Isotopes 2023年 201卷

作者： Hao Guo Qian Li Chunlei Zhang Liyang Jiang Xichao Ruan Qi Sun Chao Liu Key Laboratory of Nuclear Data China Institute of Atomic Energy BeiJing 102413 China College of Nuclear Science and Technology Beijing Normal University BeiJing 100875 China

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Saturable Absorption of an X-Ray Free-Electron-Laser Heated Solid-Density Aluminum Plasma

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Physical Review Letters 2015年第1期114卷 015003-015003页

作者： D. S. Rackstraw O. Ciricosta S. M. Vinko B. Barbrel T. Burian J. Chalupský B. I. Cho H.-K. Chung G. L. Dakovski K. Engelhorn V. Hájková P. Heimann M. Holmes L. Juha J. Krzywinski R. W. Lee S. Toleikis J. J. Turner U. Zastrau J. S. Wark Department of Physics Clarendon Laboratory University of Oxford Parks Road Oxford OX1 3PU United Kingdom Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley California 94720 USA Institute of Physics ASCR Na Slovance 2 18221 Prague 8 Czech Republic Department of Physics and Photon Science Gwangju Institute of Science and Technology Gwangju 500-712 Republic of Korea Center for Relativistic Laser Science Institute for Basic Science (IBS) Gwangju 500-712 Republic of Korea Atomic and Molecular Data Unit Nuclear Data Section IAEA P.O. Box 100 A-1400 Vienna Austria SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park California 94025 USA Department of Physics University of California Berkeley California 94720 USA Deutsches-Elektronensynchrotron DESY Notkestrasse 85 22603 Hamburg Germany IOQ Friedrich-Schiller-Universität Jena Max-Wien-Platz 1 07743 Jena Germany

High-intensity x-ray pulses from an x-ray free-electron laser are used to heat and probe a solid-density aluminum sample. The photon-energy-dependent transmission of the heating beam is studied through the use of a photodiode. Saturable absorption is observed, with the resulting transmission differing significantly from the cold case, in good agreement with atomic-kinetics simulations.

关键词： X-rays ELECTRONS LASERS DYNAMICS ATOMS

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Coexistence and Competition of the Short-Range Incommensurate Antiferromagnetic Order with the Superconducting State of BaFe2−xNixAs2

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Physical Review Letters 2012年第24期108卷 247002-247002页

作者： Huiqian Luo Rui Zhang Mark Laver Zahra Yamani Meng Wang Xingye Lu Miaoyin Wang Yanchao Chen Shiliang Li Sung Chang Jeffrey W. Lynn Pengcheng Dai Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Laboratory for Neutron Scattering Paul Scherrer Institute CH-5232 Villigen Switzerland Department of Physics Technical University of Denmark DK-2800 Kongens Lyngby Denmark Canadian Neutron Beam Centre National Research Council Chalk River Laboratories Chalk River Ontario K0J 1J0 Canada Department of Physics and Astronomy The University of Tennessee Knoxville Tennessee 37996-1200 USA Science and Technology on Nuclear Data Laboratory China Institute of Atomic Energy Beijing 102413 China NIST Center for Neutron Research National Institute of Standards and Technology Gaithersburg Maryland 20899 USA

Superconductivity in the iron pnictides develops near antiferromagnetism, and the antiferromagnetic (AF) phase appears to overlap with the superconducting phase in some materials such as BaFe2−xTxAs2 (where T=Co or Ni). Here we use neutron scattering to demonstrate that genuine long-range AF order and superconductivity do not coexist in BaFe2−xNixAs2 near optimal superconductivity. In addition, we find a first-order-like AF-to-superconductivity phase transition with no evidence for a magnetic quantum critical point. Instead, the data reveal that incommensurate short-range AF order coexists and competes with superconductivity, where the AF spin correlation length is comparable to the superconducting coherence length.

关键词： EXISTENCE theorems ANTIFERROMAGNETISM IRON compounds METAL ions NEUTRON scattering SUPERCONDUCTIVITY PHASE transformations (Physics) CORRELATION (Statistics) COHERENT states

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Search for the doubly charmed baryon Ω_(cc)^(+)

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science China(Physics,Mechanics & Astronomy) 2021年第10期64卷 2-13页

作者： LHCb Collaboration Centro Brasileiro de Pesquisas Físicas (CBPF) Rio de Janeiro Brazil Universidade Federal do Rio de Janeiro (UFRJ) Rio de Janeiro Brazil Center for High Energy Physics Tsinghua University Beijing 100084 China Institute Of High Energy Physics (IHEP) Beijing 100039 China School of Physics State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100091 China University of Chinese Academy of Sciences Beijing 100086 China Institute of Particle Physics Central China Normal University Wuhan 430079 China CNRS IN2P3-LAPP Univ. Savoie Mont Blanc Annecy France CNRS/IN2P3 LPC Université Clermont Auvergne Clermont-Ferrand France CNRS/IN2P3 CPPM Aix Marseille Univ Marseille France CNRS/IN2P3 IJCLab Université Paris-Saclay Orsay France Laboratoire Leprince-Ringuet CNRS/IN2P3 Ecole Polytechnique Institut Polytechnique de Paris Palaiseau France LPNHE Sorbonne Université Paris Diderot Sorbonne Paris Cité CNRS/IN2P3 Paris France I. Physikalisches Institut RWTH Aachen University Aachen Germany Fakultät Physik Technische Universität Dortmund Dortmund Germany Max-Planck-Institut für Kernphysik (MPIK) Heidelberg Germany Physikalisches Institut Ruprecht-Karls-Universität Heidelberg Heidelberg Germany School of Physics University College Dublin Dublin Ireland INFN Sezione di Bari Bari Italy INFN Sezione di Bologna Bologna Italy INFN Sezione di Ferrara Ferrara Italy INFN Sezione di Firenze Firenze Italy INFN Laboratori Nazionali di Frascati Frascati Italy INFN Sezione di Genova Genova Italy INFN Sezione di Milano Milano Italy INFN Sezione di Milano-Bicocca Milano Italy INFN Sezione di Cagliari Monserrato Italy Universita degli Studi di Padova Universita e INFN Padova Padova Italy INFN Sezione di Pisa Pisa Italy INFN Sezione di Roma La Sapienza Roma Italy INFN Sezione di Roma Tor Vergata Roma Italy Nikhef National Institute for Subatomic Physics Amsterdam Netherlands Nikhef National Institute for Subatomic Physics and VU Unive

A search for the doubly charmed baryon ?cc+ with the decay mode c Ω_(cc)^(+)→ Ξc+K-π+ is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. No significant signal is observed within the invariant mass range of 3.6 to 4.0 GeV/c2. Upper limits are set on the ratio R of the production cross-section times the total branching fraction of the Ω_(cc)^(+)→ Ξc+K-π+ decay with respect to the Ξcc++→ Λc+K-π+π+ decay. Upper limits at 95% credibility level for R in the range 0.005 to 0.11 are obtained for diferent hypotheses on the ?cc+ mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15 GeV/c.

关键词： charmed baryons limits on production of particles charmed quarks experimental tests

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