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Proceedings of the 2025 ACM/SIGDA International Symposium on Field programmable Gate Arrays

作者： Ling-Chi Yang Chi-Jui Chen Trung Le Bo-Cheng Lai Scott Hauck Shih-Chieh Hsu Institute of Electronics National Yang Ming Chiao Tung University Hsinchu Taiwan Graduate Degree Program of College of Electrical and Computer Engineering in National Yang Ming Chiao Tung University Hsinchu Taiwan Electrical and Computer Engineering in University of Washington Seattle USA Electrical and Computer Engineering University of Washington Seattle USA Physics University of Washington Seattle USA

ISBN: (纸本)9798400713965

FPGAs are a compelling substrate for supporting machine learning inference. Tools such as High-Level Synthesis and hls4ml can shorten the development cycle for deploying ML algorithms on FPGAs, but can struggle to handle the large on-chip storage needed for many of these models. In particular the high BRAM usage found in many of these flows can cause Place & Route failures during synthesis. In this paper we propose using a Simulated-Annealing based flow to perform BRAM-aware quantization. This approach trades off inference accuracy with BRAM usage, to provide a high-quality inference engine that still meets on-chip resource constraints. We demonstrate this flow for Transformer-based machine learning algorithms, which include Flash Attention in a Stream-based Dataflow architecture. Our system imposes minimal accuracy drops, yet can reduce BRAM usage by 20%-50%, and improve power efficiency by 264%-812% compared to existing Transformer-based accelerators on FPGAs

关键词： efficient transformer

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Thermo-optical properties of luminescent carbon dots produced from biomass of Orbignya speciosa (babassu coconut)

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Journal of Molecular Liquids 2025年 423卷

作者： Oliveira, Maykol Christian Damasceno Silva, Adriano Almeida Silva-Silva, Tânia Patrícia Silva, Jhaemely Gabrielly Vieira da Silva Júnior, José Ferreira Sanchez, David Bell, Maria José Valenzuela Garcia, Hans Anderson Viana, Bartolomeu Cruz Terrones, Mauricio Costa, Rubens Silva Santos, Francisco Eroni Paz Physics Department Federal University of Piauí PI 64049550 Brazil Postgraduate Program in Engineering and Materials Science Federal University of 64049550 PI Teresina Brazil Department of Physics and Center for 2-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States Federal University of Juiz de Fora Institute of Exact Sciences Department of Physics University Campus - UFJF/ ICE/ Department of Physics Martelos MG Juiz de Fora36036330 Brazil Federal Institute of Piauí Paranaíba Campus PI Parnaíba64211145 Brazil

Exploring materials with high nonlinearities derived from organic and biological sources has become a significant focus within the scientific community. Among these materials, carbon dots (CDs) synthesized from biomass have emerged as promising candidates due to their sustainable and cost-effective production methods. This study synthesized CDs from Orbignya speciosa (babassu coconut) biomass via a hydrothermal route. UV–visible absorption and Infrared spectrum analysis revealed characteristic bands associated with the formation of dots and the electronic transitions π–π* from aromatic C=C bonds in the CDs’ core and n–π* transitions of surface carboxylate groups, photoluminescence as a function of temperature and lifetime decay measurements show that the photoluminescence mechanisms in these materials due this transitions comes from electronic indirect transitions from primary sources of the core and carbonyl boundings in the surface of the material, additionally, to this the Dynamic Light Scattering (DLS) and Transmission Electronic Microscopy (TEM) give the structural properties of the dots, amorphous and with a large size distribution with a mean size of (21 ± 1) nm. Thermal lens spectroscopy (TLS) was employed to determine the material's thermal diffusivity, reaching a maximum value of 2.03 × 10−7 m2/s as a function of dilution. The Z-scan technique under continuous wave (CW) excitation at 532 nm investigated nonlinear optical properties, yielding a maximum thermal nonlinear refractive index (n2(th)) value of −5.87 × 10−5 esu. Furthermore, the photothermal efficiency of the CDs was quantified at 505 nm, demonstrating a high absorption efficiency of 94.9 %, suggesting their potential application in photothermal therapies. These findings contribute to understanding babassu coconut CDs’ thermo-optical behavior, highlighting their promise for various practical applications, particularly in biomedicine. © 2025 Elsevier B.V.

关键词： Refractive index

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Visualizing Field-free Deterministic Magnetic Switching of all–van der Waals Spin-Orbit Torque System Using Spin Ensembles in Hexagonal Boron Nitride

arXiv

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arXiv 2025年

作者： Zhang, Xi Zhou, Jingcheng Hu, Chaowei Deng, Kuangyin Wang, Chuangtang Agarwal, Nishkarsh Jin, Hanshang Al-Matouq, Faris A. Xu, Stelo Trivedi, Roshan S. Li, Senlei Rathi, Sumedh Lu, Hanyi Jiang, Zhigang Taufour, Valentin Hovden, Robert Zhao, Liuyan Cheng, Ran Xu, Xiaodong Chu, Jiun-Haw Du, Chunhui Rita Wang, Hailong School of Physics Georgia Institute of Technology AtlantaGA30332 United States Department of Physics University of Washington SeattleWA98105 United States Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California DavisCA95616 United States Department of Physics University of California San Diego La Jolla CA92093 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California RiversideCA92521 United States Department of Materials Science and Engineering University of Washington SeattleWA98105 United States

Recently, optically active spin defects embedded in van der Waals (vdW) crystals have emerged as a transformative quantum sensing platform to explore cutting-edge materials science and quantum physics. Taking advantage of excellent solid-state integrability, this new class of spin defects can be arranged in controllable nanoscale proximity of target materials in vdW heterostructures, showing great promise for improving spatial resolution and field sensitivity of current sensing technologies. Building on this state-of-the-art measurement platform, here we report hexagonal boron nitride-based quantum imaging of field-free deterministic magnetic switching of room-temperature two-dimensional magnet Fe3GaTe2 in an all-vdW spin-orbit torque (SOT) system. By visualizing SOT-driven variations of nanoscale Fe3GaTe2 magnetic stray field profile under different conditions, we have revealed how the observed magnetic switching evolves from deterministic to indeterministic behavior due to the interplay between out-of-plane spins, in-plane spins and Joule heating. This understanding, which is otherwise difficult to access by conventional transport measurements, offers valuable insights on material design, testing, and evaluation of next-generation vdW spintronic devices. Copyright © 2025, The Authors. All rights reserved.

关键词： Van der Waals forces

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Structural properties of hyperuniform Voronoi networks

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Physical Review E 2025年第3期111卷 034123-034123页

作者： Eli Newby Wenlong Shi Yang Jiao Reka Albert Salvatore Torquato Department of Physics Pennsylvania State University University Park Pennsylvania 16802 USA Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Disordered hyperuniform many-particle systems are recently discovered exotic states of matter, characterized by the complete suppression of normalized infinite-wavelength density fluctuations, as in perfect crystals, while lacking 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 by determining multiple metrics that characterize the distribution, including their average areas and corresponding variances as well as higher-order cumulants (i.e., skewness γ1 and excess kurtosis γ2). 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 of the 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 th

关键词： Gaussian distribution

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Three-dimensional construction of hyperuniform, nonhyperuniform, and antihyperuniform disordered heterogeneous materials and their transport properties via spectral density functions

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Physical Review E 2025年第3期111卷 035310-035310页

作者： Wenlong Shi Yang Jiao Salvatore Torquato Materials Science and Engineering Arizona State University Tempe Arizona 85287 USA Department of Physics Arizona State University Tempe Arizona 85287 USA Department of Chemistry Princeton University Princeton New Jersey 08544 USA Department of Physics Princeton University Princeton New Jersey 08544 USA Princeton Institute of Materials Princeton University Princeton New Jersey 08544 USA Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA

Rigorous theories connecting physical properties of a heterogeneous material to its microstructure offer a promising avenue to guide the computational material design and optimization. The spectral density function χ̃V(k), which can be obtained experimentally from scattering data, enables accurate determination of various transport and wave propagation characteristics, including the time-dependent diffusion spreadability S(t) and effective dynamic dielectric constant εe for electromagnetic wave propagation. Moreover, χ̃V(k) determines rigorous upper bounds on the fluid permeability K. Given the importance of χ̃V(k), we present here an efficient Fourier-space based computational framework to construct three-dimensional (3D) statistically isotropic two-phase heterogeneous materials corresponding to targeted spectral density functions. In particular, we employ a variety of analytical functional forms for χ̃V(k) that satisfy all known necessary conditions to construct disordered stealthy hyperuniform, standard hyperuniform, nonhyperuniform, and antihyperuniform two-phase heterogeneous material systems at varying phase volume fractions. We show that by tuning the correlations in the system across length scales via the targeted functions, one can generate a rich spectrum of distinct structures within each of the above classes of materials. Importantly, we present the first realization of antihyperuniform two-phase heterogeneous materials in 3D, which are characterized by autocovariance function χV(r) with a power-law tail, resulting in microstructures that contain clusters of dramatically different sizes and morphologies. We also determine the diffusion spreadability S(t) and estimate the fluid permeability K associated with all of the constructed materials directly from the corresponding spectral densities. Although it is well established that the long-time asymptotic scaling behavior of S(t) only depends on the functional form of χ̃V(k), with the stealthy hyperuniform a

关键词： Spectral density

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Spatio-temporal characterisation of the Beekeeper Formation of Australia: facies development, mixing of carbonate and siliciclastic materials, and influencing factors

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Petroleum Research 2025年

作者： Adhari, Muhammad Ridha Marwan Husin, Husni Ismail, Nazli Ghani, Azman A. Doctoral Program School of Engineering Post Graduate School Universitas Syiah Kuala Banda Aceh23111 Indonesia Department of Geological Engineering Universitas Syiah Kuala Banda Aceh23111 Indonesia Department of Geophysical Engineering Universitas Syiah Kuala Banda Aceh23111 Indonesia Department of Chemical Engineering Universitas Syiah Kuala Banda Aceh23111 Indonesia Department of Physics Universitas Syiah Kuala Banda Aceh23111 Indonesia Department of Geology Universiti Malaya Kuala Lumpur50603 Malaysia

The Beekeeper Formation, a mixed carbonate-siliciclastic reservoir, has long been known as a proven gas reservoir in the northern Perth Basin, Australia. However, its characteristics, and spatio-temporal distribution are still not well understood. There are two main objectives of this study: (1) to identify the main cutting facies groups/subgroups, and electrofacies of the Beekeeper Formation;and (2) to understand spatio-temporal characteristics, and development of the Beekeeper Formation. Integrated multi analyses have been conducted to achieve these objectives including cutting, wireline logging, and XRF analyses. Fifteen types of cutting components, and nine electrofacies were identified forming the Beekeeper Formation. The Beekeeper Formation consists of nine facies sub-groups, and these are classified into carbonate-dominated facies group, siliciclastic-dominated facies group, and mixed carbonate-siliciclastic facies group. Furthermore, this formation can vertically be divided into three parts on the basis of the main facies groups: the lower, middle, and upper parts. The lower and upper parts consist predominantly of siliciclastic materials, while the middle part is dominated by carbonate materials. In the north of the study area, the Beekeeper Formation consists predominantly of siliciclastic materials with minor carbonate materials, whereas in the central to south it consists mainly of carbonate material with minor-moderate siliciclastic materials. Various processes have influenced the evolution of the Beekeeper Formation including influx of siliciclastic components, mixing of carbonate and siliciclastic materials, suitable environment for the growth of carbonate biotas, sea level fluctuation, and tectonic activities. It is expected that findings from this study will provide new insights into characteristics of mixed carbonate-siliciclastic reservoirs in general, and will have regional and global applicability. © 2025 The Authors

关键词： Sea level

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Quantitative Imaging of 55CO and 18F-Labeled Tracers in a Single “Multiplexed” Pet Imaging Session

Quantitative Imaging of 55CO and 18F-Labeled Tracers in a Si...

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IEEE International Symposium on Biomedical Imaging

作者： Sarah J. Zou Irene Lim Jackson W. Foster Garry Chinn Hailey A. Houson Suzanne E. Lapi Jianghong Rao Craig S. Levin Department of Electrical Engineering Stanford University Department of Radiology and Molecular Imaging Program at Stanford (MIPS) Stanford University Chemistry and Biochemistry Department Bates College Department of Radiology University of Alabama at Birmingham Department of Bioengineering Stanford University Department of Physics Stanford University

ISBN: (数字)9798331520526

ISBN: (纸本)9798331520533

In this study, we explore the use of Cobalt-55 as a radioisotope for multiplexed PET (mPET) by utilizing its emission of a prompt gamma-ray in cascade with a positron during decay. We leverage the prompt-gamma signal to generate triple coincidences for a Co-55-labeled tracer, allowing us to distinguish it from a tracer labeled with a pure positron emitter F-18, which yields a two photon coincidence. By employing this triple versus double coincidence detection and signal processing methodology, we show the potential to separate and quantify the Co-55 signal from that of F-18. Phantom studies showed strong linear correlation $(R^{2}=0.99)$ between Co-55 double and triple coincidence counts and total Co-55 activity. Finally, we highlight the capability of this method to quantify overlapping and non-overlapping hot spots within a warm background to within a 3 to 15% error range. Moreover, we demonstrate the feasibility of simultaneously imaging two tracers in vivo during a single PET session using mice.

关键词： Multiplexing Sensitivity Translation Positrons Biomarkers Recording Labeling Positron emission tomography Isotopes Cancer

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Natural Alkaloids (Caffeine, Theobromine and Theophylline) as Dielectric Capping Layers for Gold and Aluminum Gate Electrodes in Low Operating Voltage Organic Field-Effect Transistors

IEEE Journal on Flexible Electronics

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IEEE Journal on Flexible Electronics 2025年

作者： Irimia, Cristian Vlad Yumusak, Cigdem Ban, Boyuan Leeb, Elisabeth Mayr, Felix Schimanofsky, Corina Mardare, Andrei Ionut Molnar, Maximilian Alexander Teichert, Christian Sariciftci, Niyazi Serdar Irimia-Vladu, Mihai Institute of Physical Chemistry Altenberger Str. 69 Linz4040 Austria Graz University of Technology in Graz Master of Science student in Advanced Materials Science program Austria Montanuniversität Leoben Chair of Physics Department of Physics Mechanics and Electrical Engineering Franz Josef Str. 18 Leoben8700 Austria Key Lab of Photovoltaic and Energy Conservation Materials Institute of Solid-State Physics Hefei Institute of Physical Science Hefei230031 China Altenberger Str. 69 Linz4040 Austria National Institute for Lasers Plasma and Radiation Physics Magurele077125 Romania

Three natural alkaloids: caffeine, theobromine and theophylline are reported for their application as dielectric layers in organic field effect transistors (OFETs) utilizing both gold and aluminum gate electrodes. After careful purification of the materials, a detailed analysis using x-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), contact angle (CA), impedance spectroscopy, amplitude modulated kelvin probe force microscope (AM-KPFM) and cyclic voltammetry (CV) is performed. OFET devices operating at typical voltages between 2 and 4 V have been fabricated with the investigated alkaloid films processed via blade coating (caffeine) or vacuum processing (theobromine and theophylline). The dielectric properties of these three alkaloids are measured in impedance spectroscopy and negligible leakage currents are observed when deposited in thin films as dielectric layers in OFETs on aluminum electrodes. There is a high tendency of these molecules to crystallize and form uneven surfaces. When the thin film forming properties are carefully controlled, organic alkaloids can be employed in applications involving implantable, transient or even edible electronics. © 2022 IEEE.

关键词： Fourier transform infrared spectroscopy

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Large Negative Magnetoresistance in off-Stochiometric Topological Material PrSbTe

arXiv

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arXiv 2025年

作者： Acharya, Gokul Pandey, Krishna Sharma, M.M. Wang, Jian Chhetri, Santosh Karki Nabi, Md Rafique Un Upreti, Dinesh Basnet, Rabindra Sakon, Josh Hu, Jin Department of Physics University of Arkansas FayettevilleAR United States Materials Science and Engineering Program Institute for Nanoscience and Engineering University of Arkansas FayettevilleAR United States Department of Chemistry and Biochemistry Wichita State University WichitaKS United States Department of Chemistry & Physics University of Arkansas at Pine Bluff Pine BluffAR71603 United States Department of Chemistry and Biochemistry University of Arkansas FayettevilleAR72701 United States

Magnetic topological materials LnSbTe (Ln = lanthanide) have attracted intensive attention because of the presence of interplay between magnetism, topological, and electron correlations depending on the choices of magnetic Ln elements. Varying Sb and Te composition is an efficient approach to control structural, magnetic, and electronic properties. Here we report the composition-dependent properties in PrSbxTe2-x. We identified the tetragonal-to-orthorhombic structure transitions in this material system, and very large negative magnetoresistance in the x = 0.3 composition, which might be ascribed to the coupling between magnetism and transport. Such unusual magnetotransport enables PrSbxTe2-x topological materials as a promising platform for device applications. © 2025, CC BY-NC-ND.

关键词： Magnetoresistance

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Carbon nanotube/conductive carbon black-filled natural rubber composites for strain sensing

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Materials Chemistry and physics 2025年 341卷

作者： Kitisavetjit, Wasuthon Paradee, Noppawan Ounjai, Kajornwut Kalkornsurapranee, Ekwipoo Promsung, Rawiporn Johns, Jobish Nakaramontri, Yeampon Sustainable Polymer & Innovative Composites Material Research Group Department of Chemistry Faculty of Science King Mongkut's University of Technology Thonburi Bangkok Thailand Biological Engineering Program Faculty of Engineering King Mongkut's University of Technology Thonburi Bangkok Thailand Neuroscience Center for Research and Innovation Learning Institute KMUTT Bangkok Thailand Division of Physical Sciences Faculty of Science Prince of Songkla University Hat-Yai Thailand Department of Physics Rajarajeswari College of Engineering Bangalore India

Strain sensors were developed using conductive natural rubber (NR) and epoxidized natural rubber (ENR) composites filled with carbon nanotubes (CNT) and carbon black (CCB) to evaluate their rapid recovery after elastic deformation. The CCB concentration was set at 1.5 times the CNT concentration, with CNT and CCB contents maximized at 25 and 37.5 parts per hundred rubbers (phr), respectively. The crosslink propagation, mechanical and dynamic mechanical properties, and morphological characteristics were analyzed to elucidate the effect of the CNT/CCB hybrid filler within the NR and ENR matrices. Increasing the CNT/CCB content above 5/7.5 phr reduced the tensile strength and elongation at break due to filler agglomeration. However, the crosslink density, modulus, and production time improved. Compared to NR composites, ENR composites exhibited superior properties, attributed to the improved dispersion and distribution of fillers facilitated by the polarity of the ENR molecular chains. The selected composites were subjected to piezoresistive testing to evaluate the performance of strain sensors under stretching, compression, and bending protocols. The results revealed that CNT/CCB-filled ENR composites exhibited high sensitivity in tension and bending tests, while NR composites demonstrated appropriate signal responses in compression modes. This behavior was attributed to the critical CNT:CCB ratio of 20:30 phr, which enabled an optimal correlation between modulus and extensibility in the rubber matrix. This balance facilitated interactions between rubber molecular chains and the hybrid filler surface under multidirectional forces. These findings offer valuable insights for motion detection applications, particularly in scenarios involving deformation in multiple directions. © 2025

关键词： Tensile strength

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