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arXiv 2022年

作者： Ruzayqat, Hamza Beskos, Alexandros Crisan, Dan Jasra, Ajay Kantas, Nikolas Applied Mathematics and Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 KSA Saudi Arabia Department of Statistical Science University College London LondonWC1E 6BT United Kingdom Department of Mathematics Imperial College London LondonSW7 2AZ United Kingdom

We study the problem of unbiased estimation of expectations with respect to (w.r.t.) π a given, general probability measure on (d, B(d)) that is absolutely continuous with respect to a standard Gaussian measure. We focus on simulation associated to a particular class of diffusion processes, sometimes termed the Schrödinger-Föllmer Sampler, which is a simulation technique that approximates the law of a particular diffusion bridge process {Xt}tϵ[0,1]on d, d ϵ 0. This latter process is constructed such that, starting at X0= 0, one has X1∼ π. Typically, the drift of the diffusion is intractable and, even if it were not, exact sampling of the associated diffusion is not possible. As a result, [10, 16] consider a stochastic Euler-Maruyama scheme that allows the development of biased estimators for expectations w.r.t. π. We show that for this methodology to achieve a mean square error of O(ϵ2), for arbitrary ϵ > 0, the associated cost is O(ϵ-5). We then introduce an alternative approach that provides unbiased estimates of expectations w.r.t. π, that is, it does not suffer from the time discretization bias or the bias related with the approximation of the drift function. We prove that to achieve a mean square error of O(ϵ2), the associated cost (which is random) is, with high probability, O(ϵ-2| log(ϵ)|2+δ), for any δ > 0. We implement our method on several examples including Bayesian inverse *** Codes 60J60, 62D05, 65C40 © 2022, CC BY.

关键词： Diffusion

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Drone-borne calibration pulser for radio observatories detecting ultra-high-energy cosmic rays and neutrinos 38

Drone-borne calibration pulser for radio observatories detec...

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38th International Cosmic Ray Conference, ICRC 2023

作者： Nam, J. Kuo, C.-Y. Shin, B.K. Chen, P. Chen, Y. Hsu, S.-Y. Huang, J.-J. Huang, M.-H.A. Leung, C.H. Liu, T.-C. Wang, S.-H. Wang, M.-Z. Wang, Y.-H. Besson, D. Novikov, A. Hornhuber, C. Young, R. Department of Physics National Taiwan University Taipei Taiwan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei Taiwan Ulsan National Institute of Science and Technology Ulsan Korea Republic of Department of Energy and Resources National United University Miaoli Taiwan Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu300 Taiwan Department of applied physics National PingTung university PingTung900 Taiwan Chung Cheng Institute of Technology National Defense University TaoYuan335 Taiwan Undergraduate Degree Program of Systems Engineering and Technology National Yang Ming Chiao Tung University Hsinchu300 Taiwan Department of Physics and Astronomy University of Kansas Lawrence United States Instrumentation Design Lab University of Kansas Lawrence United States Moscow Russia Institute of Astronomy and Astrophysics Academia Sinica Astronomy-Mathematics Building No. 1 Sec. 4 Roosevelt Rd. Taipei Taiwan

We report on the development of a drone-borne calibration pulser (cal-pulser) for radio observatories detecting ultra-high energy (UHE) cosmic rays and neutrinos. This system allows us to calibrate the radio detector in its field of view regardless of the accessibility of the site. The system is compact and sufficiently lightweight to be attached to a commercial drone. It consists of a solid-state high-power pulse generator, a programmable attenuator, a transmitting antenna, and a differential GPS (D-GPS) module. The drone, with the ∼1.3 kg payload, has a typical flight time of around 25 minutes, corresponding to a maximum flight distance of around 10 km. After developing the first version of the system in 2019, it successfully demonstrated its calibration performance with the TAROGE stations in Taiwan and the TAROGE-M station in Mt. Melbourne, Antarctica. In 2022, the system was upgraded with a dual-band D-GPS for more reliable operation and more accurate determination of the coordinates of the cal-pulser. In addition to the cal-pulser, we investigated aerial photogrammetry using the built-in camera and the D-GPS, which is an efficient method to determine the coordinates of the detector. For objects within 10 m of the drone, an accuracy of a few millimeter was achieved. These drone-borne cal-pulser and the photogrammetry have become essential calibration procedures in the TAROGE-M experiment. We suggest these approaches may find application in many other radio experiments that detect UHE cosmic rays and neutrinos, such as ARIANNA, BEACON, GRAND, as well as IceCube-Gen2. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmic rays

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Experimental implementation of an efficient test of quantumness

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Physical Review A 2024年第1期109卷 012610-012610页

作者： Laura Lewis Daiwei Zhu Alexandru Gheorghiu Crystal Noel Or Katz Bahaa Harraz Qingfeng Wang Andrew Risinger Lei Feng Debopriyo Biswas Laird Egan Thomas Vidick Marko Cetina Christopher Monroe Institute for Quantum Information and Matter and Department of Computing and Mathematical Sciences California Institute of Technology Pasadena California 91125 USA Division of Physics Mathematics and Astronomy California Institute of Technology Pasadena California 91125 USA Joint Quantum Institute Departments of Physics and Electrical and Computer Engineering University of Maryland College Park Maryland 20742 USA Joint Center for Quantum Information and Computer Science NIST/University of Maryland College Park Maryland 20742 USA IonQ Inc. College Park Maryland 20740 USA Departments of Electrical and Computer Engineering University of Maryland College Park Maryland 20742 USA Institute for Theoretical Studies ETH Zürich Zürich CH 8001 Switzerland Duke Quantum Center and Department of Physics Duke University Durham North Carolina 27708 USA Department of Electrical and Computer Engineering Duke University Durham North Carolina 27708 USA Chemical Physics Program and Institute for Physical Science and Technology University of Maryland College Park Maryland 20742 USA

A test of quantumness is a protocol where a classical user issues challenges to a quantum device to determine if it exhibits nonclassical behavior, under certain cryptographic assumptions. Recent attempts to implement such tests on current quantum computers rely on either interactive challenges with efficient verification or noninteractive challenges with inefficient (exponential time) verification. In this paper, we execute an efficient noninteractive test of quantumness on an ion-trap quantum computer. Our results significantly exceed the bound for a classical device's success.

关键词： Quantum cryptography Quantum information with trapped ions Quantum protocols Quantum verification

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Design of experiments as a strategy for modulating the colloidal stability, physico-chemical properties and drug-delivery potential of small mesoporous silica nanoparticles

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Advanced Powder technology 2023年第10期34卷

作者： Lestari, Windy Ayu Saputra, Ozi Adi Díaz-García, Diana Wahyuningsih, Sayekti Gómez-Ruiz, Santiago Wibowo, Fajar Rakhman Magister Program in Chemistry Faculty of Mathematics and Natural Sciences Universitas Sebelas Maret Surakarta57126 Indonesia Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Sebelas Maret Surakarta57126 Indonesia COMET-NANO Group Departamento de Biología y Geología Física y Química Inorgánica Universidad Rey Juan Carlos Calle Tulipán s/n Madrid MóstolesE-28933 Spain Institute of Chemistry Taiwan International Graduate Program Sustainable Chemical Science and Technology Academia Sinica Taipei115 China Department of Chemical Engineering National Taiwan University Taipei10617 China

The synthesis of highly stable small mesoporous silica nanoparticles (SMSN) in colloid dispersions is still challenging for biomedical applications. This study is focus on the successfully synthesis and formulation of porous, highly dispersed and colloidal stable SMSN via the soft–templating method. This study reports how the differences in synthesis variables, namely, temperature, amount of triethylamine (TEA) and/or cetyltrimethylammonium bromide (CTAB) influence the morphology and textural properties of SMSN. The analysis of the particle size, surface area, pore size, pore volume, zeta potential, and colloidal stability (represent by absorbance decreasing rate) show that temperature is the most influential factor governing the preparation of SMSN. The optimal conditions found for the synthesis of these nanoparticles were 50 °C, using a molar ratio between TEA and CTAB (3.5971: 1). Therefore, our study shows interesting insights on the effect of each variable to control the morphology and properties of small MSN for the design of this kind of nanoparticulated systems, therefore, giving valuable data to be considered for the future construction of tailor-made effective drug carrier materials. © 2023 The Society of Powder technology Japan

关键词： Synthesis (chemical)

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Effect of Different Types of Preparation Methods on the Properties of Tempo-Oxidized Bacterial Cellulose Powder Film

SSRN

引用

SSRN 2023年

作者： Rahmadiawan, Dieter Abral, Hairul Shi, Shih-Chen Ilham, Mohammad Khalid Sugiarti, Eni Muslimin, Ahmad Novi Ilyas, R.A. Zainul, Rahadian Department of Mechanical Engineering Universitas Negeri Padang Sumatera Barat Padang25173 Indonesia Tainan Taiwan Laboratory of Nanoscience and Technology Department of Mechanical Engineering Andalas University Sumatera Barat Padang25163 Indonesia Research Collaboration Center for Nanocellulose BRIN-Andalas University Padang25163 Indonesia Serpong Indonesia Weaponry Technology Study Program Defense Technology Faculty Indonesia Defense University Sentul Bogor16810 Indonesia School of Chemical and Energy Engineering Faculty of Engineering Universiti Teknologi Malaysia Johor Bahru81310 Malaysia Department of Chemistry Faculty of Mathematics and Natural Science Universitas Negeri Padang West Sumatera 25171 Indonesia

The preparation method of cellulose films plays a vital role in their properties. This work aims to characterize 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized bacterial cellulose powder (TOBCP) films prepared with three different methods (casting, boiling-casting, and boiling-vacuum). It is found that film by casting (CT film) shows the best electrical properties. A light-emitting diode (LED) in a direct current circuit connected to the CT film glows the most brightly. However, this film had lower tensile strength and thermal stability than films from boiling and boiling-vacuum techniques. The boiling-vacuum film presents the most compact fiber structure and the highest tensile and thermal properties. This film also shows the lowest electrical properties and the dimmest LED light. These results demonstrate the TOBCP properties from different methods that can be used to prepare film with desirable properties. © 2023, The Authors. All rights reserved.

关键词： Light emitting diodes

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Subdiffusive wave transport and weak localization transition in three-dimensional stealthy hyperuniform disordered systems

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Physical Review B 2022年第6期105卷 064204-064204页

作者： F. Sgrignuoli S. Torquato L. Dal Negro Department of Electrical and Computer Engineering & Photonics Center Boston University 8 Saint Mary's Street Boston Massachusetts 02215 USA Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials and Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08540 USA Division of Material Science and Engineering Boston University 15 Saint Mary's Street Brookline Massachusetts 02446 USA Department of Physics Boston University 590 Commonwealth Avenue Boston Massachusetts 02215 USA

The purpose of this work is to understand the fundamental connection between structural correlations and light localization in three-dimensional (3D) open scattering systems of finite size. We numerically investigate the transport of vector electromagnetic waves scattered by resonant electric dipoles spatially arranged in 3D space by stealthy hyperuniform disordered point patterns. Three-dimensional stealthy hyperuniform disordered systems are engineered with different structural correlation properties determined by their degree of stealthiness χ. Such fine control of exotic states of amorphous matter enables the systematic design of optical media that interpolate in a tunable fashion between uncorrelated random structures and crystalline materials. By solving the electromagnetic multiple scattering problem using Green's matrix spectral method, we establish a transport phase diagram that demonstrates a distinctive transition from a diffusive to a weak localization regime beyond a critical scattering density that depends on χ. The transition is characterized by studying the Thouless number and the spectral statistics of the scattering resonances. In particular, by tuning the χ parameter, we demonstrate large spectral gaps and suppressed subradiant proximity resonances, facilitating light localization. Moreover, consistently with previous studies, our results show a region of the transport phase diagram where the investigated scattering systems become transparent. Our work provides a systematic description of the transport and weak localization properties of light in stealthy hyperuniform structures and motivates the engineering of photonic systems with enhanced light-matter interactions for applications to both classical and quantum devices.

关键词： Anderson localization Light-matter interaction Mesoscopics Photonics Scattering theory Weak localization Metamaterials

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Thermal Conductivity of Water at Extreme Conditions

arXiv

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arXiv 2023年

作者： Zhang, Cunzhi Puligheddu, Marcello Zhang, Linfeng Car, Roberto Galli, Giulia Pritzker School of Molecular Engineering University of Chicago ChicagoIL60637 United States Materials Science Division Center for Molecular Engineering Argonne National Laboratory LemontIL60439 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials Princeton University PrincetonNJ08544 United States Department of Chemistry University of Chicago ChicagoIL60637 United States

Measuring the thermal conductivity (κ) of water at extreme conditions is a challenging task and few experimental data are available. We predict κ for temperatures and pressures relevant to the conditions of the Earth mantle, between 1,000 and 2,000 K and up to 22 GPa. We employ close to equilibrium molecular dynamics simulations and a deep neural network potential fitted to density functional theory data. We then interpret our results by computing the equation of state of water on a fine grid of points and using a simple model for κ. We find that the thermal conductivity is weakly dependent on temperature and monotonically increases with pressure with an approximate square-root behavior. In addition we show how the increase of κ at high pressure, relative to ambient conditions, is related to the corresponding increase in the sound velocity. Although the relationships between the thermal conductivity, pressure and sound velocity established here are not rigorous, they are sufficiently accurate to allow for a robust estimate of the thermal conductivity of water in a broad range of temperatures and pressures, where experiments are still difficult to perform. Copyright © 2023, The Authors. All rights reserved.

关键词： Thermal conductivity

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Artificial neural network approach for turbulence models: A local framework

arXiv

引用

arXiv 2021年

作者： Xie, Chenyue Xiong, Xiangming Wang, Jianchun Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Mechanics and Aerospace Engineering Southern University of Science and Technology Shenzhen518055 China

A local artificial neural network (LANN) framework is developed for turbulence modeling. The Reynolds-averaged Navier-Stokes (RANS) unclosed terms are reconstructed by artificial neural network (ANN) based on the local coordinate system which is orthogonal to the curved walls. We verify the proposed model for the flows over periodic hills. The correlation coefficients of the RANS unclosed terms predicted by the LANN model can be made larger than 0.96 in an a priori analysis, and the relative error of the unclosed terms can be made smaller than 18%. In an a posteriori analysis, detailed comparisons are made on the results of RANS simulations using the LANN and Spalart-Allmaras (SA) models. It is shown that the LANN model performs better than the SA model in the prediction of the average velocity, wall-shear stress and average pressure, which gives the results that are essentially indistinguishable from the direct numerical simulation (DNS) data. The LANN model trained in low Reynolds number Re = 2800 can be directly applied in the cases of high Reynolds numbers Re = 5600, 10595, 19000, 37000 with accurate predictions. Furthermore, the LANN model is verified for flows over periodic hills with varying slopes. These results suggest that the LANN framework has a great potential to be applied to complex turbulent flows with curved *** Codes 76F40, 76F55, 76N99 Copyright © 2021, The Authors. All rights reserved.

关键词： Neural networks

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Z-scheme S, B co-doped g-C3N4 nanotube@MnO2 heterojunction with visible-light-responsive for enhanced photodegradation of diclofenac by peroxymonosulfate activation

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Chemical engineering Journal 2023年第Part2期452卷

作者： Dung Nguyen, Manh Binh Nguyen, Thanh Hai Tran, Linh Giang Nguyen, Thuy Fatimah, Is Prasetyo Kuncoro, Eko Doong, Ruey-An Department of Biomedical Engineering and Environmental Sciences National Tsing Hua University Hsinchu30013 Taiwan Institute of Aquatic Science and Technology National Kaohsiung University of Science and Technology Kaohsiung City81157 Taiwan Center of Crop Research for Adaptation to Climate Change Thai Nguyen University of Agriculture and Forestry Quyet Thang Ward Thai Nguyen City Viet Nam Department of Chemistry Faculty of Mathematics and Natural Science Universitas Islam Indonesia Kampus Terpadu UII J1. Kaliurang Km 14 Sleman Yogyakarta Indonesia Environmental Engineering Program Faculty of Science and Technology University of Airlangga Surabaya60115 Indonesia Institute of Analytical and Environmental Sciences National Tsing Hua University 101 Sec. 2 Kuang Fu Road Hsinchu30013 Taiwan

In this study, the manganese dioxide (MnO2) nanosheets were successfully embedded onto boron and sulfur co-doped g-C3N4 (CNBS) nanotubes to construct the flower-like core–shell CNBS@MnO2 heterojunction with Z-scheme structure for the enhanced photodegradation of diclofenac (DCF) in the presence of peroxymonosulfate (PMS) and 460-nm visible light. The CNBS@MnO2 provides large specific surface area and reduced interfacial resistance for rapid electron transport. Moreover, the redox cycling of Mn species effectively activates PMS to produce sulfate radicals for DCF photodegradation. The PMS-based photodegradation of DCF over CNBS@MnO2 displays the excellent photodegradation performance after 15 min of irradiation, and the efficiency is highly dependent on initial pH, ion species, and concentrations of PMS and DCF. The CNBS@MnO2 also shows its excellent stability and reusability over ten cycles. Besides, h+, O2●− and SO4●− are the dominantly reactive species for the enhanced degradation of DCF over Z-scheme CNBS@MnO2 heterojunction. The possible reaction mechanism as well as the degradation pathway of DCF over CNBS@MnO2 in the presence of PMS is also proposed. Results clearly highlight the superior photoactivity of Z-scheme CNBS@MnO2 toward micropollutant degradation by PMS activation, which can open an avenue to fabricate the g-C3N4 nanotube@metal oxide structure as an effective activator for water and wastewater purification. © 2022 Elsevier B.V.

关键词： Heterojunctions

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The Role of Heterogeneity in Autonomous Perimeter Defense Problems

arXiv

引用

arXiv 2022年

作者： Adler, Aviv Mickelin, Oscar Ramachandran, K. Sukhatme, Gaurav S. Karaman, Sertac Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States Program in Applied and Computational Mathematics Princeton University Princeton NJ08544 United States Department of Computer Science University of Southern California Los AngelesCA90089 United States Department of Aeronautics and Astronautics Massachusetts Institute of Technology CambridgeMA02139 United States

When is heterogeneity in the composition of an autonomous robotic team beneficial and when is it detrimental? We investigate and answer this question in the context of a minimally viable model that examines the role of heterogeneous speeds in perimeter defense problems, where defenders share a total allocated speed budget. We consider two distinct problem settings and develop strategies based on dynamic programming and on local interaction rules. We present a theoretical analysis of both approaches and our results are extensively validated using simulations. Interestingly, our results demonstrate that the viability of heterogeneous teams depends on the amount of information available to the defenders. Moreover, our results suggest a universality property: across a wide range of problem parameters the optimal ratio of the speeds of the defenders remains nearly constant. Copyright © 2022, The Authors. All rights reserved.

关键词： Dynamic programming

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