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arXiv 2024年

作者： McKeown, Trevor Michael Gach, H. Hao, Yao An, Hongyu Robinson, Clifford G. Cuculich, Phillip S. Yang, Deshan Medical Physics Program Duke University United States Department of Radiation Oncology Duke University United States Department of Radiation Oncology School of Medicine Washington University in Saint Louis United States Department of Radiology School of Medicine Washington University in Saint Louis United States Department of Biomedical Engineering Washington University in Saint Louis United States Department of Cardiology School of Medicine Washington University in Saint Louis United States

Background: Quantification of cardiac motion on pre-treatment CT imaging for stereotactic arrhythmia radiotherapy patients is difficult due to the presence of image artifacts caused by metal leads of implantable cardioverter-defibrillators (ICDs). The CT scanners’ onboard metal artifact reduction tool does not sufficiently reduce these artifacts. More advanced artifact reduction techniques require the raw CT projection data and thus are not applicable to already reconstructed CT images. New methods are needed to accurately reduce the metal artifacts in already reconstructed CTs to recover the otherwise lost anatomical information. Purpose: To develop a methodology to automatically detect metal artifacts in cardiac CT scans and inpaint the affected volume with anatomically consistent structures and values. Methods: Breath-hold ECG-gated 4DCT scans of 12 patients who underwent cardiac radiation therapy for treating ventricular tachycardia were collected. The metal artifacts in the images caused by the ICD leads were manually contoured. A 2D U-Net deep learning (DL) model was developed to segment the metal artifacts automatically using eight patients for training, two for validation, and two for testing. A dataset of 592 synthetic CTs was prepared by adding segmented metal artifacts from the patient 4DCT images to artifact-free cardiac CTs of 148 patients. A 3D image inpainting DL model was trained to refill the metal artifact portion in the synthetic images with realistic image contents that approached the ground truth artifact-free images. The trained inpainting model was evaluated by analyzing the automated segmentation results of the four heart chambers with and without artifacts on the synthetic dataset. Additionally, the raw cardiac patient images with metal artifacts were processed using the inpainting model and the results of metal artifact reduction were qualitatively inspected. Results: The artifact detection model worked well and produced a Dice score of 0.9

关键词： Computerized tomography

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Emulating Complex Synapses Using Interlinked Proton Conductors

arXiv

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arXiv 2024年

作者： Zhang, Lifu Li, Ji-An Hu, Yang Jiang, Jie Lai, Rongjie Benna, Marcus K. Shi, Jian Department of Materials Science and Engineering Rensselaer Polytechnic Institute TroyNY12180 United States Neurosciences Graduate Program University of California San Diego La Jolla CA92093 United States Department of Mathematics Purdue University West LafayetteIN47907 United States Department of Neurobiology School of Biological Sciences University of California at San Diego La Jolla CA92093 United States Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute TroyNY12180 United States

In terms of energy efficiency and computational speed, neuromorphic electronics based on non-volatile memory devices is expected to be one of most promising hardware candidates for future artificial intelligence (AI). However, catastrophic forgetting, networks rapidly overwriting previously learned weights when learning new tasks, remains as a pivotal hurdle in either digital or analog AI chips for unleashing the true power of brain-like computing. To address catastrophic forgetting in the context of online memory storage, a complex synapse model (the Benna-Fusi model) has been proposed recently[1], whose synaptic weight and internal variables evolve following a diffusion dynamics. In this work, by designing a proton transistor with a series of charge-diffusion-controlled storage components, we have experimentally realized the Benna-Fusi artificial complex synapse. The memory consolidation from coupled storage components is revealed by both numerical simulations and experimental observations. Different memory timescales for the complex synapse are engineered by the diffusion length of charge carriers, the capacity and number of coupled storage components. The advantage of the demonstrated complex synapse in both memory capacity and memory consolidation is revealed by neural network simulations of face familiarity detection. Our experimental realization of the complex synapse suggests a promising approach to enhance memory capacity and to enable continual learning. Copyright © 2024, The Authors. All rights reserved.

关键词： Computational efficiency

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Accelerating Radiochemistry Development: Automated Robotic Platform for Performing Up to 64 Droplet Radiochemical Reactions in a Morning

SSRN

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SSRN 2023年

作者： Jones, Jason Do, Viviann Lu, Yingqing van Dam, R. Michael Los AngelesCA United States Physics and Biology in Medicine Interdepartmental Graduate Program UCLA United States Department of Molecular & Medical Pharmacology David Geffen School of Medicine UCLA United States Department of Biochemistry UCLA United States Department of Bioengineering Henry Samueli School of Engineering and Applied Science UCLA United States

The growing discovery and development of novel radiopharmaceuticals and radiolabeling methods requires an increasing capacity for radiochemistry experiments. However, such studies typically rely on radiosynthesizers designed for clinical batch production rather than research, greatly limiting throughput. Two general solutions are being pursued to address this: developing new synthesis optimization algorithms to minimize how many experiments are needed, and developing apparatus with enhanced experiment throughput. We describe here a novel high-throughput system based on performing arrays of droplet-based reactions at 10 μL volume scale in parallel. The automatic robotic platform can perform a set of 64 experiments in ~3 h (from isotope loading to crude product, plus sampling onto TLC plates), plus ~1 h for off-line radio-TLC analysis and radioactivity measurements, rather than the weeks or months that would be needed using a conventional system. We show the high repeatability and low crosstalk of the platform and demonstrate optimization studies for two 18F-labeled tracers. This novel automated platform greatly increases the practicality of performing arrays of droplet reactions by eliminating human error, vastly reducing tedium and fatigue, minimizing radiation exposure, and freeing up radiochemist time for more intellectually valuable pursuits. © 2023, The Authors. All rights reserved.

关键词： Drops

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Cell-type continuous electromagnetic radiation system generating millimeter waves for active denial system applications

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Defence Technology（防务技术） 2022年第10期18卷 1895-1913页

作者： Sun-Hong Min Ohjoon Kwon Matlabjon Sattorov Seontae Kim In-Keun Baek Seunghyuk Park Ranjan Kumar Barik Anirban Bera Dongpyo Hong Seonmyeong Kim Bong Hwan Hong Chawon Park Sukhwal Ma Minho Kim Kyo Chul Lee Yong Jin Lee Han Byul Kwon Young Joon Yoo Sang Yoon Park Gun-Sik Park Korea Institute of Radiological and Medical Sciences(KIRAMS) Seoul01812South Korea Institute for Basic Science Center for Axion and Precision Physics ResearchDaejeon34141South Korea Center for THz-Driven Biomedical Systems Department of Physics and AstronomyCollege of Natural SciencesSeoul National UniversitySeoul08826South Korea Center for Applied Electromagnetic Research Advanced Institute of Convergence TechnologySuwonGyeonggi-do16229South Korea R&D Department Seoul-TeracomInc.Suwon16229South Korea Mechatronics R&D Center Samsung Electronics Co.Ltd.Hwasung18448South Korea Hanwha Corporation Gumi730-030South Korea Council of Scientific and Industrial Research Central Electronics Engineering Research InstitutePilani333031India Home Economics Education/Biosystems and Biomedical Sciences Korea UniversitySeoul02841South Korea Current affiliation of Seontae Kim:Young IN ACE 1 F60Anyangcheondong-roDongan-guAnyang-siGyeonggi-do14042South Korea.

The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living *** irradiates a biological sample placed in a 30×30×50 cm^(3)cell with electromagnetic waves in the 3.15-mm-wavelength region(with an output of≥1 W)and analyzes the temperature change of the sample.A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency(RF)energy and radiates it to the target through an antenna,increasing the temperature through the absorption of RF energy in the *** system causes pain and ultimately reduces combat power.A cell-type continuous electromagnetic radiation system consisting of four parts—an electromagnetic-wave generator,a highvoltage power supply,a test cell,and a system controller—generates an RF signal of≥1 W in a continuous waveform at a 95-GHz center frequency,as well as a chemical solution with a dielectric constant similar to that of the skin of a living *** increase of 5°C lasting approximately 10 s was confirmed through an experiment.

关键词： Millimeter waves Terahertz waves Coupled-cavity backward wave oscillator(CCBWO) Cell-type continuous electromagnetic radiation Active denial system(ADS) Directed-energy weapon(DEW)

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Constrained Optimization of Charged Particle Tracking with Multi-Agent Reinforcement Learning

arXiv

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arXiv 2025年

作者： Kortus, Tobias Keidel, Ralf Gauger, Nicolas R. Kieseler, Jan Aehle, Max Alme, Johan Barnaföldi, Gergely Gábor Bodova, Tea Borshchov, Vyacheslav van den Brink, Anthony Chaar, Mamdouh Eikeland, Viljar Feofilov, Gregory Garth, Christoph Gauger, Nicolas R. Genov, Georgi Grøttvik, Ola Helstrup, Håvard Igolkin, Sergey Keidel, Ralf Kobdaj, Chinorat Kortus, Tobias Leonhardt, Viktor Mehendale, Shruti Mulawade, Raju Ningappa Odland, Odd Harald O’Neill, George Papp, Gábor Peitzmann, Thomas Pettersen, Helge Egil Seime Piersimoni, Pierluigi Protsenko, Maksym Rauch, Max Rehman, Attiq Ur Richter, Matthias Röhrich, Dieter Santana, Joshua Schilling, Alexander Seco, Joao Songmoolnak, Arnon Sudár, Ákos Sølie, Jarle Rambo Tambave, Ganesh Tymchuk, Ihor Ullaland, Kjetil Varga-Kofarago, Monika Wagner, Boris Xiao, RenZheng Yang, Shiming Yokoyama, Hiroki Kaiserslautern Germany Karlsruhe Germany Kaiserslautern67663 Germany Department of Physics and Technology University of Bergen Bergen5007 Norway Wigner Research Centre for Physics Budapest Hungary Kharkiv Ukraine Institute for Subatomic Physics Utrecht University/Nikhef Utrecht Netherlands St. Petersburg University St. Petersburg Russia Kaiserslautern67663 Germany Department of Computer Science Electrical Engineering and Mathematical Sciences Western Norway University of Applied Sciences Bergen5020 Norway University of Applied Sciences Worms Worms Germany Institute of Science Suranaree University of Technology Nakhon Ratchasima Thailand Department of Oncology and Medical Physics Haukeland University Hospital Bergen5021 Norway Institute for Physics Eötvös Loránd University 1/A Pázmány P. Sétány BudapestH-1117 Hungary UniCamillus – Saint Camillus International University of Health Sciences Rome Italy Department of Physics University of Oslo Oslo0371 Norway Department of Biomedical Physics in Radiation Oncology DKFZ—German Cancer Research Center Heidelberg Germany Department of Physics and Astronomy Heidelberg University Heidelberg Germany Budapest University of Technology and Economics Budapest Hungary Department of Diagnostic Physics Division of Radiology and Nuclear Medicine Oslo University Hospital Oslo Norway Bhubaneswar India College of Mechanical & Power Engineering China Three Gorges University Yichang China

Reinforcement learning demonstrated immense success in modelling complex physics-driven systems, providing end-to-end trainable solutions by interacting with a simulated or real environment, maximizing a scalar reward signal. In this work, we propose, building upon previous work, a multi-agent reinforcement learning approach with assignment constraints for reconstructing particle tracks in pixelated particle detectors. Our approach optimizes collaboratively a parametrized policy, functioning as a heuristic to a multidimensional assignment problem, by jointly minimizing the total amount of particle scattering over the reconstructed tracks in a readout frame. To satisfy constraints, guaranteeing a unique assignment of particle hits, we propose a safety layer solving a linear assignment problem for every joint action. Further, to enforce cost margins, increasing the distance of the local policies predictions to the decision boundaries of the optimizer mappings, we recommend the use of an additional component in the blackbox gradient estimation, forcing the policy to solutions with lower total assignment costs. We empirically show on simulated data, generated for a particle detector developed for proton imaging, the effectiveness of our approach, compared to multiple single- and multi-agent baselines. We further demonstrate the effectiveness of constraints with cost margins for both optimization and generalization, introduced by wider regions with high reconstruction performance as well as reduced predictive instabilities. Our results form the basis for further developments in RL-based tracking, offering both enhanced performance with constrained policies and greater flexibility in optimizing tracking algorithms through the option for individual and team rewards. Copyright © 2025, The Authors. All rights reserved.

关键词： Constrained optimization

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Chiral anomaly and Weyl orbit in three-dimensional Dirac semimetal Cd3As2 grown on Si

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Nanotechnology 2024年第16期35卷 165002-165002页

作者： Lin, Wei-Chen Tsai, Peng-Ying Zou, Jia-Zhu Lee, Jie-Ying Kuo, Chun-Wei Lee, Hsin-Hsuan Pan, Ching-Yang Yang, Cheng-Hsueh Chen, Sheng-Zong Wang, Jyh-Shyang Jiang, Pei-Hsun Liang, Chi-Te Chuang, Chiashain Taiwan International Graduate Program Academia Sinica Taipei115 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu300 Taiwan Graduate Institute of Applied Physics National Taiwan University Taipei106 Taiwan National Taiwan University Taipei106 Taiwan Department of Electronic Engineering Chung Yuan Christian University Taoyuan320 Taiwan Department of Physics Chung Yuan Christian University Taoyuan320 Taiwan Department of Physics National Taiwan Normal University 106 Taiwan Research Center for Semiconductor Materials and Advanced Optics Chung Yuan Christian University Taoyuan320 Taiwan

Preparing Cd3As2, which is a three-dimensional (3D) Dirac semimetal in certain crystal orientation, on Si is highly desirable as such a sample may well be fully compatible with existing Si CMOS technology. However, there is a dearth of such a study regarding Cd3As2 films grown on Si showing the chiral anomaly. Here, for the first time, we report the novel preparation and fabrication technique of a Cd3As2 (112) film on a Si (111) substrate with a ZnTe (111) buffer layer which explicitly shows the chiral anomaly with a nontrivial Berry’s phase of π. Despite the Hall carrier density ( n 3 D ≈ 9.42 × 10 17 cm−3) of our Cd3As2 film, which is almost beyond the limit for the portents of a 3D Dirac semimetal to emerge, we observe large linear magnetoresistance in a perpendicular magnetic field and negative magnetoresistance in a parallel magnetic field. These results clearly demonstrate the chiral magnetic effect and 3D Dirac semimetallic behavior in our silicon-based Cd3As2 film. Our tailoring growth of Cd3As2 on a conventional substrate such as Si keeps the sample quality, while also achieving a low carrier concentration. © 2024 IOP Publishing Ltd.

关键词： II-VI semiconductors

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Structural Properties of Hyperuniform Networks

arXiv

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arXiv 2024年

作者： Newby, Eli Shi, Wenlong Jiao, Yang Albert, Reka Torquato, Salvatore Department of Physics Pennsylvania State University University ParkPA16802 United States Materials Science and Engineering Arizona State University TempeAZ85287 United States Department of Physics Arizona State University TempeAZ85287 United States Department of Chemistry Princeton University PrincetonNJ08544 United States Department of Physics Princeton University PrincetonNJ08544 United States Princeton Institute of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States

Disordered hyperuniform many-particle systems are recently discovered exotic states of matter, characterized by a complete suppression of normalized infinite-wavelength density fluctuations, as in perfect crystals, and lack of conventional long-range order, as in liquids and glasses. In this work, we begin a program to quantify the structural properties of nonhyperuniform and hyperuniform networks. In particular, large two-dimensional (2D) Voronoi networks (graphs) containing approximately 10,000 nodes are created from a variety of different point configurations, including the antihyperuniform hyperplane intersection process (HIP), nonhyperuniform Poisson process, nonhyperuniform random sequential addition (RSA) saturated packing, and both non-stealthy and stealthy hyperuniform point processes. We carry out an extensive study of the Voronoi-cell area distribution of each of the networks through determining multiple metrics that characterize the distribution, including their higher-cumulants (i.e., skewness 1 and excess kurtosis 2). We show that the HIP distribution is far from Gaussian, as evidenced by a high skewness (γ1 = 3.16) and large positive excess kurtosis (γ2 = 16.2). The Poisson (with γ1 = 1.07 and γ2 = 1.79) and non-stealthy hyperuniform (with γ1 = 0.257 and γ2 = 0.0217) distributions are Gaussian-like distributions, since they exhibit a small but positive skewness and excess kurtosis. The RSA (with γ1 = 0.450 and γ2 = -0.0384) and the highest stealthy hyperuniform distributions (with γ1 = 0.0272 and γ2 = -0.0626) are also non-Gaussian because of their low skewness and negative excess kurtosis, which is diametrically opposite non-Gaussian behavior of the HIP. The fact that the cell-area distributions of large, finite-sized RSA and stealthy hyperuniform networks (e.g., with N ≈ 10, 000 nodes) are narrower, have larger peaks, and smaller tails than a Gaussian distribution implies that in the thermodynamic limit the distributions should exhibit compact suppo

关键词： Gaussian distribution

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Measuring 3D Chemistry at 1 nm Resolution with Fused Multi-Modal Electron Tomography

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Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada 2023年第1期29卷 1394-1395页

作者： Schwartz, Jonathan Di, Zichao Wendy Jiang, Yi Cho, Min Gee Qian, Yiwen Gu, Junsi Rozeveld, Steve Ercius, Peter Fessler, Jeffrey A. Xu, Ting Scott, Mary Hovden, Robert Department of Materials Science and Engineering University of Michigan Ann Arbor MI United States Mathematics and Computer Science Division Argonne National Laboratory Lemont IL United States Advanced Photon Source Argonne National Laboratory Lemont IL United States Department of Materials Science and Engineering University of California at Berkeley Berkeley CA United States National Center for Electron Microscopy Lawrence Berkeley National Laboratory Berkeley CA United States Dow Chemical Co. Midland MI United States Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI United States Materials Science Division Lawrence Berkeley National Laboratory Berkeley CA United States Applied Physics Program University of Michigan Ann Arbor MI United States

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Neutron Mammography Feasibility Studied Using Mcnpx and a Breast Voxel Anthropomorphic Phantom

SSRN

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SSRN 2024年

作者： Alghamdi, Ali A.A. Ma, Andy K.W. Mhareb, M.H.A. Saleh, Gameel Abuelhia, Elfateh Alshammari, Hamed A. Bradley, David Andrew Department of Radiological Sciences College of Applied Medical Science Imam Abdulrahman Bin Faisal University P.O. Box 2435 Dammam31441 Saudi Arabia School of Medicine Royal College of Surgeons in Ireland-Bahrain P.O.Box 15503 Adliya Bahrain Department of Physics College of Science Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia Department of Biomedical Engineering College of Engineering Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam Saudi Arabia School of Mathematics and Physics University of Surrey GuildfordGU2 7XH United Kingdom Applied Physics and Radiation Technologies Group CCDCU School of Engineering and Technology Sunway University Bandar Sunway Selangor Darul Ehsan 47500 Malaysia

The non-destructive imaging technique of neutron radiography offers particular advantage over X- or gamma-rays for internal inspection of low atomic number objects. Specifically, neutron interactions give rise to considerably greater contrast between the various low Z components making up such media, better enabling the visualization of structural details. The work herein explores the potential of neutron radiography for mammography. The focus is on Monte Carlo simulations using voxel phantoms, playing a vital role in analyzing neutron interactions within objects, including in biological bodies. Forming a feasibility study, investigation is made of the use of MCNPX 2.5.0 and a high-resolution breast voxel phantom, investigating collimation design and material effects in neutron imaging. Grayscale postprocessing techniques are employed to enhance image contrast. The results, reflected in image quality, demonstrate contrast improvement, influenced by specifics of the collimation and the impact of different neutron energies. Fast neutrons from the fission spectrum exhibit improved overall contrast, while polycarbonate is seen to be a promising collimation material due to its flexibility and availability. Further investigations are required in order to optimize collimation, to perform dose calculations, and to compare neutron radiography with that of traditional photon mammography. Overall, the study highlights the potential of neutron radiography in medical imaging and suggests avenues for future research and development. © 2024, The Authors. All rights reserved.

关键词： Monte Carlo methods

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Integrated application of grafted ZnO and fungicide to control the fungicide-resistant Colletotrichum spp

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Journal of the Taiwan Institute of Chemical Engineers 2024年 155卷

作者： Chang, Tao-Ho Chen, Yi-Chi Lai, Yu-Fang Wu, Tzu-Chien Lai, Chian-Hui Hsueh, Han-Yu Chang, Pi-Fang Linda Program in Plant Health Care Academy of Circular Economy National Chung Hsing University Nantou540216 Taiwan Innovation and Development Center of Sustainable Agriculture National Chung Hsing University Taichung402202 Taiwan Master Program for Plant Medicine and Good Agricultural Practice National Chung Hsing University Taichung402202 Taiwan Department of Material Science & Engineering National Chung Hsing University Taichung402202 Taiwan Graduate Institute of Biomedical Engineering National Chung Hsing University Taichung402202 Taiwan Department of Medicinal and Applied Chemistry Kaohsiung Medical University Kaohsiung807378 Taiwan Department of Plant Pathology National Chung Hsing University 402202 Taiwan

Background: The Food and Agriculture Organization has reported approximately 40 % of food loss due to damage from plant pests and diseases, including fungal infections. Continuous application of agrichemicals for controlling fungal infection cause the occurrence of fungicide resistance. Colletotrichum spp., major causal agents for strawberry anthracnose, have gained concern for fungicide resistance issues. Methods: We developed novel antifungal strategies in the present study by integrating multibranched flower-like ZnO (fZnO) and agrochemicals (trifloxystrobin). fZnO compounds were synthesised using an eco-friendly and efficient hydrothermal method. Charged polymers with steric structures, such as hydrophilic polyacrylic acid (PAA) and polyethyleneimine (PEI), were grafted onto fZnO surfaces to improve the suspension ability of the compounds. We used the grafted fZnO compounds in combination with the fungicide trifloxystrobin to evaluate the in vitro and in vivo activities. Significant findings: Grafted fZnO (80 ppm) and trifloxystrobin (100 ppm) effectively inhibited the growth of fungicide-resistant Colletotrichum spp. and limited strawberry anthracnose on leaves. PEI-grafted fZnO shows promise as an eco-friendly additive in sustainable agriculture due to its photocatalytic activity and ability to withstand environmental factors. © 2023

关键词： Zinc oxide

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