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2021 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2021

作者： Pourashraf, Shirin Gonzalez-Montoro, Andrea Cates, Joshua W. Zhao, Zhixiang Won, Jun Yeon Sung Lee, Jae Levin, Craig S. Stanford University Department of Radiology StanfordCA94305 United States Berkeley National Laboratory Applied Nuclear Physics Program at Lawrence BerkeleyCA94720 United States Shanghai Jiao Tong University School of Biomedical Engineering Shanghai China Seoul National University Department of Nuclear Medicine and Biomedical Sciences Seoul110-744 Korea Republic of Stanford University Molecular Imaging Program Departments of Radiology Bioengineering Physics and Electrical Engineering StanfordCA94305 United States

ISBN: (纸本)9781665421133

We have embedded a dynamic time-over-threshold (DynTOT) block in our scalable TOF-PET detector readout electronics to linearize the multiplexed energy spectra while keeping 100 ps FWHM Coincidence Time Resolution (CTR) performance. This DynTOT block is constructed by off-the-shelve components and consumes only 20 mW power per detector 'layer' in our design. Using 3×3×10 mm3 "LGSO"crystals coupled to arrays of 3×3 mm² SiPMs, energy resolution of 13.8±0.1%, 13.9±0.3%, and 17.1±0.6% were experimentally achieved for conventional pulse height, DynTOT, and conventional TOT methods, respectively. Including the DynTOT method, coincidence data were experimentally acquired using a low jitter FPGA-based TDC, and 103.6 ± 1.1 ps FWHM CTR was achieved, demonstrating the robustness of our novel and scalable timing electronic chain. © 2021 IEEE.

关键词： Medical imaging

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Topological Surface State Evolution in Bi2Se3 via Surface Etching

arXiv

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arXiv 2024年

作者： Yue, Ziqin Huang, Jianwei Wang, Ruohan Li, Jia-Wan Rong, Hongtao Guo, Yucheng Wu, Han Zhang, Yichen Kono, Junichiro Zhou, Xingjiang Hou, Yusheng Wu, Ruqian Yi, Ming Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices Center for Neutron Science and Technology School of Physics Sun Yat-Sen University Guangzhou510275 China Institute of Physics Chinese Academy of Sciences Beijing100190 China Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Department of Physics and Astronomy University of California Irvine IrvineCA92697 United States

Topological insulators are materials with an insulating bulk interior while maintaining gapless boundary states against back scattering. Bi2Se3 is a prototypical topological insulator with a Dirac-cone surface state around Γ. Here, we present a controlled methodology to gradually remove Se atoms from the surface Se-Bi-Se-Bi-Se quintuple layers, eventually forming bilayer-Bi on top of the quintuple bulk. Our method allows us to track the topological surface state and confirm its robustness throughout the surface modification. Importantly, we report a relocation of the topological Dirac cone in both real space and momentum space, as the top surface layer transitions from quintuple Se-Bi-Se-Bi-Se to bilayer-Bi. Additionally, charge transfer among different surface layers is identified. Our study provides a precise method to manipulate surface configurations, allowing for the fine-tuning of the topological surface states in Bi2Se3, which represents a significant advancement towards nano-engineering of topological states. Copyright © 2024, The Authors. All rights reserved.

关键词： Topological insulators

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Experimental implementation of an efficient test of quantumness

引用

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 Considerations for 3D Position Sensitive Scintillation Detectors that Achieve 100 ps Coincidence Time Resolution

Design Considerations for 3D Position Sensitive Scintillatio...

引用

2021 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2021

作者： Pourashraf, Shirin Zhao, Zhixiang Gonzalez-Montoro, Andrea Cates, Joshua W. Yeon Won, Jun Sung Lee, Jae Levin, Craig S. Stanford University Department of Radiology StanfordCA94305 United States Shanghai Jiao Tong University School of Biomedical Engineering Shanghai China Lawrence Berkeley National Laboratory Applied Nuclear Physics Program BerkeleyCA94720 United States Seoul National University Department of Nuclear Medicine and Biomedical Sciences Seoul110-744 Korea Republic of Stanford University Molecular Imaging Program Departments of Radiology Bioengineering Physics and Electrical Engineering StanfordCA94305 United States

ISBN: (纸本)9781665421133

We have studied design considerations for three dimension positioning sensitive (3DPS) scalable TOF- PET detectors that achieve 100 ps coincidence time resolution (CTR). These scintillation detectors are based on 3×3×10 mm3 'LGSO' crystals side- coupled to arrays of 3×3 mm2 SiPMs. A CPLD is used to provide 3 mm positioning resolution along the length of each crystal element. Revised mixed-signal front-end electronics decreased the power dissipation by 200% and increased the detector packing fraction while preserving the CTR performance. A low timing jitter FPGA-based TDC was used for data acquisition of the timing channels. Measured CTR was 102.2 ± 1.3 ps FWHM using a 22Na point source. © 2021 IEEE.

关键词： Data acquisition

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Understanding and controlling the geometry of memory organization in RNNs

arXiv

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arXiv 2025年

作者： Haputhanthri, Udith Storan, Liam Jiang, Yiqi Raheja, Tarun Shai, Adam Akengin, Orhun Miolane, Nina Schnitzer, Mark J. Dinc, Fatih Tanaka, Hidenori CNC Program Stanford University United States James H. Clark Center for Biomedical Engineering & Sciences Stanford University United States Kipo AI San Francisco United States Simplex Astera Institute EmeryvilleCA United States Geometric Intelligence Lab UC Santa Barbara Santa Barbara United States Howard Hughes Medical Institute United States Physics & Informatics Laboratories NTT Research Inc. SunnyvaleCA94085 United States Kavli Institute for Theoretical Physics UC Santa Barbara United States CBS-NTT Program in Physics of Intelligence Harvard University CambridgeMA94305 United States

Training recurrent neural networks (RNNs) is a high-dimensional process that requires updating numerous parameters. Therefore, it is often difficult to pinpoint the underlying learning mechanisms. To address this challenge, we propose to gain mechanistic insights into the phenomenon of abrupt learning by studying RNNs trained to perform diverse short-term memory tasks. In these tasks, RNN training begins with an initial search phase. Following a long period of plateau in accuracy, the values of the loss function suddenly drop, indicating abrupt learning. Analyzing the neural computation performed by these RNNs reveals geometric restructuring (GR) in their phase spaces prior to the drop. To promote these GR events, we introduce a temporal consistency regularization that accelerates (bioplausible) training, facilitates attractor formation, and enables efficient learning in strongly connected networks. Our findings offer testable predictions for neuroscientists and emphasize the need for goal-agnostic secondary mechanisms to facilitate learning in biological and artificial networks. © 2025, CC BY.

关键词： Phase space methods

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VALIDATION OF RAPID'S ALGORITHM FOR CONTROL RODS MOVEMENT USING THE JSI TRIGA REACTOR

VALIDATION OF RAPID'S ALGORITHM FOR CONTROL RODS MOVEMENT US...

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2021 International Conference on Mathematics and Computational Methods Applied to Nuclear Science and engineering, M and C 2021

作者： Mascolino, Valerio Haghighat, Alireza Pungerčič, Anže Snoj, Luka Nuclear Engineering Program Virginia Tech 7054 Haycock Road Falls ChurchVA22043 United States Reactor Physics Department Jožef Stefan Institute Jamova Cesta 39 LjubljanaSi-1000 Slovenia

ISBN: (纸本)9781713886310

As part of a collaboration between Virginia Tech and the Jožef Stefan Institute (JSI) of Slovenia the Multi-stage Response-function Transport (MRT) code system RAPID has been undergoing an extensive computational and experimental validation campaign using the JSI TRIGA Mark-II reactor. To do so a novel algorithm for treatment of control rods based on the Fission Matrix (FM) method was implemented in RAPID, referred to as FM-CRd. In this paper, we discuss the methodology and compare RAPID predictions to a set of experimental data collected in February 2019 utilizing large in-core fission chambers during rod-swap experiments at the JSI TRIGA reactor. The FM-CRd algorithm is shown to be able to very accurately account for the neutron source redistribution, calculating detector responses within around 1% of the measurements throughout the experiment. Copyright © 2021 AMERICAN NUCLEAR SOCIETY, INCORPORATED, LA GRANGE PARK, ILLINOIS *** rights reserved.

关键词： control rods experimental validation fission matrix RAPID

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Deep Learning Methods for Plankton Identification: A Bibliometric Analysis and General Review 1

Deep Learning Methods for Plankton Identification: A Bibliom...

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1st International Conference on Smart Technology, Applied Informatics, and engineering, APICS 2022

作者： Ardhi, Ovide Decroly Wisnu Soeprobowati, Tri Retnaningsih Adi, Kusworo Prakasa, Esa Rachman, Arief School of Postgraduate Studies Universitas Diponegoro Doctoral of Information System Program Semarang Indonesia Vocational School Universitas Sebelas Maret Department of Informatics Engineering Surakarta Indonesia Universitas Diponegoro Faculty of Science of Mathematics Department of Biology Semarang Indonesia Universitas Diponegoro Faculty of Science of Mathematics Department of Physics Semarang Indonesia Bandung Indonesia Jakarta Indonesia

ISBN: (数字)9781665489850

ISBN: (纸本)9781665489850

This study investigates trends in deep learning research on microscopic images to identify and classify plankton. We performed a bibliometric analysis using VOSviewer to display the visualizations. The first step is to extract the relevant journals from the Scopus database. Extraction from relevant journals found 42 articles, including 21 journals and 21 conferences. We analyzed publication trends and analyzes of co-authorship, co-occurrence, and citations. In addition, it examines the collaborative relationship between authors by country, the emergence of co-author keywords, and the citation of journal sources. We found that the researchers performed plankton classification tasks that achieved high accuracy (>90%). The plankton identification method uses a deep learning architecture based on the Convolutional Neural Network. Among the architectures are AlexNet, GoogleNet, InceptionV3, VGGNet (16.19), ResNet (50.101), DenseNet, NasNet, MobileNetV2, ResidualNet, Shufflenet, EfficienNet, and CapsNet. Some researchers combine CNN with SparseConvNets, LMP, SVM, MorphoCluster, and Quantification Algorithm (CC, AC, PCC, PAC, Hdy). Some methods also implement transfer learning, fine-tuning, and advanced features. In addition to the CNN approach, End-to-End Object Detection with transformers is one of the new approaches in the future to identify plankton. © 2022 IEEE.

关键词： Deep learning

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Penrose Super-Radiance in a Synthetically Rotating Metasurface

Penrose Super-Radiance in a Synthetically Rotating Metasurfa...

引用

2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2022

作者： Moussa, Hady Alù, Andrea City University of New York Photonics Initiative Advanced Science Research Center New York10031 United States City College of the City University of New York Department of Electrical Engineering New York10031 United States City University of New York Physics Program Graduate Center New YorkNY10016 United States

ISBN: (数字)9781665496582

ISBN: (纸本)9781665496582

Super-radiant amplification of scattering in a rotating medium was predicted by Sir Penrose as an exotic astrophysics phenomenon. Here we demonstrate its electromagnetic analogue using spatio-temporally modulated metasurfaces that experience a form of synthetic rotation. We consider excitations with signals carrying orbital angular momentum (OAM), highly beneficial for multiplexed wireless networks that demand high data rate capacity. The metasurface efficiently couples and can amplify selected OAM orders based on a phenomenon analogous to Penrose super-radiance. We build, analyze, and simulate a single circuit element, modulated in time through varactors, that efficiently manipulates three OAM orders and selectively amplifies them. We then show the possibility of observing angular Doppler shift and amplifying selected OAM signals using an array of these elements forming a metasurface. © 2022 IEEE.

关键词： Astrophysics

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Statistical mechanics of thermostatically controlled multizone buildings

引用

Physical Review E 2023年第3期107卷 034140-034140页

作者： Lucas Fuentes Valenzuela Lindell Williams Michael Chertkov Department of Electrical Engineering Stanford University 350 Jane Stanford Way Stanford California 94305 USA Department of Physics Cornell University 109 Clark Hall Ithaca New York 14853 USA Program in Applied Mathematics & Department of Mathematics University of Arizona 617 N. Santa Rita Tucson Arizona 85721 USA

We study the collective phenomena and constraints associated with the aggregation of individual cooling units from a statistical mechanics perspective. These units are modeled as thermostatically controlled loads (TCLs) and represent zones in a large commercial or residential building. Their energy input is centralized and controlled by a collective unit—the air handling unit (AHU)—delivering cool air to all TCLs, thereby coupling them together. Aiming to identify representative qualitative features of the AHU-to-TCL coupling, we build a simple but realistic model and analyze it in two distinct regimes: the constant supply temperature (CST) and the constant power input (CPI) regimes. In both cases, we center our analysis on the relaxation dynamics of individual TCL temperatures to a statistical steady state. We observe that while the dynamics are relatively fast in the CST regime, resulting in all TCLs evolving around the control set point, the CPI regime reveals the emergence of a bimodal probability distribution and two, possibly strongly separated, timescales. We observe that the two modes in the CPI regime are associated with all TCLs being in the same low or high airflow states, with an occasional collective transition between the modes akin to Kramer's phenomenon in statistical physics. To the best of our knowledge, this phenomenon has been overlooked in building energy systems despite its direct operational implications. It highlights a trade-off between occupational comfort—related to zonal temperature variations—and energy consumption.

关键词： Electric power transmission Energy-efficient infrastructure engineering Fluctuations & noise Irreversible processes Fokker–Planck equation Langevin algorithm Langevin equation Monte Carlo methods physics & society

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Non-Hermitian selective thermal emitter for thermophotovoltaics

Non-Hermitian selective thermal emitter for thermophotovolta...

引用

Conference on Lasers and Electro-Optics (CLEO)

作者： Ciril S. Prasad Samuel C. Raphaelson Gururaj V. Naik Department of Electrical and Computer Engineering Rice University Houston TX USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Department of Material Science and NanoEngineering Rice University Houston TX USA

Selective thermal emitters can boost the efficiency of heat-to-electricity conversion in thermophotovoltaic systems only if their spectral selectivity is high. We demonstrate a non-Hermitian metasurface-based selectiv... 详细信息

ISBN: (纸本)9781957171258

关键词： Emissivity Light intensity Optical constants Silicon Temperature Thermal emission

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