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arXiv 2023年

作者： Nawano, Aya Schroers, Jan Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

Metallic glasses are frequently used as structural materials. Therefore, it is important to develop methods to predict their mechanical response as a function of the microstructure prior to loading. We develop a novel coarse-grained spring network model, which describes the mechanical response of metallic glasses using an equivalent series network of springs, which can break and re-form to mimic atomic rearrangements during deformation. To validate the spring network model, we perform numerical simulations of quasistatic, uniaxial tensile deformation of Lennard-Jones and embedded atom method (EAM) potentials for Cu50Zr50 metallic glasses in the absence of large-scale shear band formation. We consider samples prepared using a wide range of cooling rates and with different amounts of crystalline order. We show that both the Lennard-Jones and EAM models possess qualitatively similar stress σ versus strain γ curves. By specifying five parameters in the spring network model (ultimate strength, strain at ultimate strength, slopes of σ(γ) at γ = 0 and at large strain, and strain at fracture where σ = 0), we can accurately describe the form of the stress-strain curves during uniaxial tension for the computational studies of Cu50Zr50, as well as recent experimental studies of several Zr-based metallic glasses. For the computational studies of Cu50Zr50, we find that the yield strain distribution is shifted to larger strains for slowly cooled glasses compared to rapidly cooled glasses. In addition, the average number of new springs and their rate of formation decreases with decreasing cooling rate. These effects offset each other at large strains, causing the stress-strain curve to become independent of the sample preparation protocol in this regime. In future studies, we will extract the parameters that define the spring network model directly from atomic rearrangements that occur during uniaxial deformation. © 2023, CC BY-NC-ND.

关键词： Metallic glass

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A study of why we need to reassess full reference image quality assessment with medical images

arXiv

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arXiv 2024年

作者： Breger, Anna Biguri, Ander Landman, Malena Sabaté Selby, Ian Amberg, Nicole Brunner, Elisabeth Gröhl, Janek Hatamikia, Sepideh Karner, Clemens Ning, Lipeng Dittmer, Sören Roberts, Michael Schönlieb, Carola-Bibiane University of Cambridge Department of Applied Mathematics and Theoretical Physics Cambridge United Kingdom Medical University of Vienna Center of Medical Physics and Biomedical Engineering Vienna Austria Emory University Department of Mathematics Atlanta United States University of Cambridge Department of Radiology Cambridge United Kingdom Medical University of Vienna Department of Neurology Vienna Austria University of Cambridge Department of Physics Cambridge United Kingdom Cancer Research UK Cambridge Institute University of Cambridge United Kingdom Department of Medicine Krems an der Donau Austria Austrian Center for Medical Innovation and Technology Wiener Neustadt Austria Harvard Medical School Brigham and Women’s Hospital BostonMA United States

Image quality assessment (IQA) is indispensable in clinical practice to ensure high standards, as well as in the development stage of machine learning algorithms that operate on medical images. The popular full reference (FR) IQA measures PSNR and SSIM are known and tested for working successfully in many natural imaging tasks, but discrepancies in medical scenarios have been reported in the literature, highlighting the gap between development and actual clinical application. Such inconsistencies are not surprising, as medical images have very different properties than natural images, and PSNR and SSIM have neither been targeted nor properly tested for medical images. This may cause unforeseen problems in clinical applications due to wrong judgment of novel methods. This paper provides a structured and comprehensive overview of examples where PSNR and SSIM prove to be unsuitable for the assessment of novel algorithms using different kinds of medical images, including real-world MRI, CT, OCT, X-Ray, digital pathology and photoacoustic imaging data. Therefore, improvement is urgently needed in particular in this era of AI to increase reliability and explainability in machine learning for medical imaging and beyond. Lastly, we will provide ideas for future research as well as suggesting guidelines for the usage of FR-IQA measures applied to medical images. © 2024, CC BY-NC-ND.

关键词： Clinical research

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Metal ratio and bimetal nanoarchitectonics of ammonia-based fluoride complex induced nickel hydroxide and manganese oxide composites as active materials of an energy storage device

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Journal of Energy Storage 2024年 80卷

作者： Hsu, Chuan-Chih Yu, You Zher Wu, Chung-Hsien Lee, Pin-Yan Chen, Hung-Ming Husain, Sadang Kongvarhodom, Chutima Hsiao, Yu-Cheng Lin, Lu-Yin Division of Cardiovascular Surgery Department of Surgery School of Medicine College of Medicine Taipei Medical University Taiwan Division of Cardiovascular Surgery Department of Surgery Taipei Medical University Hospital Taiwan Department of Chemical Engineering and Biotechnology National Taipei University of Technology Taipei Taiwan Gingen Technology Co. LTD. Rm. 7 10F. No.189 Sec. 2 Keelung Rd. Xinyi Dist. Taipei11054 Taiwan Department of Physics Faculty of Mathematics and Natural Science Lambung Mangkurat University Banjarmasin70124 Indonesia Department of Chemical Engineering King Mongkut's University of Technology Thonburi 126 Pracha-u-thit Toong-kru Bangkok10140 Thailand Department of Chemical Engineering Ming Chi University of Technology New Taipei City24301 Taiwan Cell Physiology and Molecular Image Research Center Wan Fang Hospital Taipei Medical University Taipei11696 Taiwan International PhD Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Stanford Byers Center for Biodesign Stanford University CA94305-5428 United States Graduate Institute of Biomedical Optomechatronics College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan

Nickel and manganese compounds are widely applied as efficient battery-type active materials for energy storage devices, due to high theoretical capacities and abundant redox states for generating redox reactions to store charges. Morphology plays significant roles on energy storage ability. Structure directing agent (SDA) is widely reported to have ability for modulating configurations of active materials and to achieve excellent surface properties. In this work, it is the first time to use NH4BF4 and NH4HF2 as structure directing agents for synthesizing nickel manganese compounds derived from ZIF67 as active materials of energy storage devices. Bimetallic compounds are composed of nickel hydroxide and manganese oxide, which presents the favorable two-dimensional flower-like structure with high surface area and abundant redox states. The largest specific capacitance (CF) of 1358.2 F/g corresponding to the capacity of 226.4 mAh/g are achieved for the bimetallic compound synthesized using the Ni to Mn precursor ratio of 1 to 1 (NiMn11). The energy storage device assembled using NiMn11 and reduced graphene oxide on Ni foams presents a maximum energy density of 11.45 Wh/kg at the power density of 0.35 kW/kg, and excellent long-term stability with the CF retention of 85.6% and Coulombic efficiency of 87.5% after 10,000 cycles. © 2023

关键词： Fluorine compounds

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Optically Tunable Many-Body Exciton-Phonon Quantum Interference

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Advanced Science 2024年第40期11卷 e2404741页

作者： Chang, Si-Jie Huang, Po-Chun Su, Jia-Sian Hsieh, Yu-Wei Quiroz Reyes, Carlos Jose Fan, Ting-Hsuan Sun, Han-Sheng Nguyem, Ai-Phuong Liu, Te-I Cheng, Ho-Wen Lin, Ching-Wei Hayashi, Michitoshi Yong, Chaw-Keong Department of Physics National Taiwan University Taipei10617 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei106319 Taiwan International Ph.D. Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University New Taipei235603 Taiwan Department of Chemistry National Tsing Hua University Hsinchu300044 Taiwan International Graduate Program of Molecular Science and Technology National Taiwan University Taipei106319 Taiwan Center for Condensed Matter Sciences National Taiwan University Taipei10617 Taiwan Center of Atomic Initiative for New Materials National Taiwan University Taipei10617 Taiwan National Center for Theoretical Sciences Taipei10617 Taiwan

This study introduces a novel paradigm for achieving widely tunable many-body Fano quantum interference in low-dimensional semiconducting nanostructures, beyond the conventional requirement of closely matched energy levels between discrete and continuum states observed in atomic Fano systems. Leveraging Floquet engineering, the remarkable tunability of Fano lineshapes is demonstrated, even when the original discrete and continuum states are separated by over 1 eV. Specifically, by controlling the quantum pathways of discrete phonon Raman scattering using femtosecond laser pulses, the Raman intermediate states across the excitonic Floquet band are tuned. This manipulation yields continuous transitions of Fano lineshapes from antiresonance to dispersive and to symmetric Lorentzian profiles, accompanied by significant variations in Fano parameter q and Raman intensity spanning 2 orders of magnitude. A subtle shift in the excitonic Floquet resonance is further shown, achieved by controlling the intensity of the femtosecond laser, which profoundly modifies quantum interference strength from destructive to constructive interference. The study reveals the crucial roles of Floquet engineering in coherent light-matter interactions and opens up new avenues for coherent control of Fano quantum interference over a broad energy spectrum in low-dimensional semiconducting nanostructures. © 2024 The Author(s). Advanced Science published by Wiley-VCH GmbH.

关键词： Femtosecond lasers

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Tunability of Magnetization in Hexagonal Perovskite Sr6co5o15 Ceramics Through 20% Fe-Substitution

SSRN

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SSRN 2023年

作者： Xu, Han-Shu Zeng, Suyuan Fang, Shijie Huang, Yuhu Xie, Wen Huang, Haoliang Lu, Yalin Tang, Kai-Bin Department of Applied Physics School of Biomedical Engineering Anhui Medical University Hefei230032 China Hefei National Research Center for Physical Sciences at the Microscale Department of Chemistry University of Science and Technology of China Hefei230026 China College of Chemistry and Chemical Engineering Liaocheng University Liaocheng252059 China Department of Physics Southern University of Science and Technology Guangdong Shenzhen518055 China Anhui Laboratory of Advanced Photon Science and Technology University of Science and Technology of China Hefei230026 China

Magnetism, transport and specific heat measurements have been performed to the hexagonal perovskite 20% Fe-substituted Sr6Co5O15 (that is Sr6(Co0.8Fe0.2)5O15) polycrystalline samples with quasi-one-dimensional structure. The system exhibits paramagnetism above 270 K, and with decreasing temperature, it undergoes two ferromagnetic phase transitions FM-I and FM-II at 220 K and 170 K, respectively, which correspondingly show two downward jumps on the resistivity curve of 0 T. The 20% Fe-substituting-induced changes in magnetic properties are discussed to be due to the changes in spin exchanges. © 2023, The Authors. All rights reserved.

关键词： Strontium compounds

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Screening confinement of entanglements: Role of a self-propelling end inducing ballistic chain reptation

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Physical Review E 2022年第2期106卷 L022501-L022501页

作者： Xue-Zheng Cao Holger Merlitz Chen-Xu Wu M. Gregory Forest Department of Physics Xiamen University Xiamen 361005 People's Republic of China Leibniz-Institut für Polymerforschung Dresden 01069 Dresden Germany Departments of Mathematics Applied Physical Sciences Biomedical Engineering University of North Carolina at Chapel Hill Chapel Hill North Carolina 27599-3250 USA

Synthetic and natural nanomaterials with self-propelling mechanisms continue to be explored to boost chain mobility beyond normal reptation in the crowded environments of entangled chains. Here we employ scaling theory and numerical simulations to demonstrate that activating one chain end of a singular or isolated chain boosts entanglement-constrained chain reptation from the one-dimensional diffusive mobility as described by the de Gennes–Edwards–Doi model to ballistic motion along the entanglement tube contour. The active chain is effectively screened from the constraint of entanglements on length scales exceeding the tube size.

关键词： Drug delivery Reptation Active matter Self-propelled particles Single polymer chains Molecular dynamics Polymer scaling theory

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Reduction of interface defects in gate-recessed GaN HEMTs by neutral beam etching

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Materials Today Advances 2024年 23卷

作者： Yu, Chia Hao Chiang, Wei Hsiang Chen, Yi-Ho Samukawa, Seiji Wuu, Dong Sing Chung, Chin-Han Hsiao, Ching-Lien Horng, Ray Hua Institute of Electronics National Yang Ming Chiao Tung University Department of Materials Science and Engineering National Chung Hsing University Graduate Degree Program of College of Electrical and Computer Engineering National Yang Ming Chiao Tung University Institute of Comunications Engineering National Yang Ming Chiao Tung University Department of Applied Materials and Optoelectronic Engineering National Chi Nan University International College of Semiconductor Technology National Yang Ming Chiao Tung University Thin Film Physics Division Department of Physics Chemistry and Biology (IFM) Linköping University

This study investigates and compares the impact of different etching techniques on the fabrication of GaN high electron mobility transistors (HEMTs) between the inductively coupled plasma reactive ion etching (ICP-RIE) and the neutral beam etching (NBE) for the gate recess. By conducting direct current analysis, it was found that devices manufactured using the NBE exhibited superior electrical performance as compared with those produced using the ICP-RIE. These enhanced electrical characteristics include a transconductance of up to 100.4 mS/mm, a threshold voltage (V_th) of −2.3 V, an on/off current ratio of 1.1 × 10⁹, a subthreshold swing (S.S.) of 99.63 mV/dec, and a remarkably low gate leakage current. Additionally, we noted varying degrees of hysteresis in the I–V characteristics were related to process disparities possibly leading to interface defects. Multi-frequency capacitance-voltage (C–V) measurements were used to identify the interface defects at the oxide/AlGaN interface of the gate. The results revealed that devices fabricated using the NBE exhibited a lower interface defect density as compared with those fabricated using the ICP-RIE, thereby elucidating the reduced hysteresis observed in the I–V characteristics. These findings indicated the significant advantages of the NBE process in the fabrication of GaN HEMTs. © 2024 The Authors

关键词： GaN HEMTs Gate recess Interface defects Multi-frequency C–V Neutral beam etching

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Quincke Oscillations of Colloids at Planar Electrodes

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Physical Review Letters 2021年第25期126卷 258001-258001页

作者： Zhengyan Zhang Hang Yuan Yong Dou Monica Olvera de la Cruz Kyle J. M. Bishop Department of Chemical Engineering Columbia University New York New York 10027 USA Applied Physics Program Northwestern University Evanston Illinois 60208 USA Department of Materials Science and Engineering Northwestern University Evanston Illinois 60208 USA

Dielectric particles in weakly conducting fluids rotate spontaneously when subject to strong electric fields. Such Quincke rotation near a plane electrode leads to particle translation that enables physical models of active matter. In this Letter, we show that Quincke rollers can also exhibit oscillatory dynamics, whereby particles move back and forth about a fixed location. We explain how oscillations arise for micron-scale particles commensurate with the thickness of a field-induced boundary layer in the nonpolar electrolyte. This work enables the design of colloidal oscillators.

关键词： Electrokinetic flows Active matter Self-propelled particles

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Analysis of high-power packages for white-light-emitting diode lamps with remote phosphor

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MRS Online Proceedings Library 2021年第1期892卷 166-171页

作者： Hong Luo Jong Kyu Kim Yangang Xi E. Fred Schubert Jaehee Cho Cheolsoo Sone Yongjo Park Department of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute Troy USA Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy USA Photonics Program Team Samsung Advanced Institute of Technology Suwon Korea

An optimized packaging configuration for high-power white-light-emitting diode (LED) lamps that employs a diffuse reflector cup, a remote phosphor and a hemi-spherically-shaped encapsulation is presented. Ray tracing simulations for this configuration show that the phosphor efficiency can be enhanced by up to 50% over conventional packages. It is experimentally shown that dichromatic LED lamps with remote phosphor and diffuse reflector cup configuration have higher phosphor efficiency by 15.4% for blue-pumped yellow phosphor and by 27% for ultraviolet-pumped blue phosphor over conventional packages. Those improvements are attributed to reduced absorption of the phosphorescence by the LED chip and the reduction of deterministic optical modes trapped inside the encapsulant.

关键词： packaging optoelectronic optical properties

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Quantum Logic Enhanced Sensing in Solid-State Spin Ensembles

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Physical Review Letters 2023年第10期131卷 100801-100801页

作者： Nithya Arunkumar Kevin S. Olsson Jner Tzern Oon Connor A. Hart Dominik B. Bucher David R. Glenn Mikhail D. Lukin Hongkun Park Donhee Ham Ronald L. Walsworth Department of Physics Harvard University Cambridge Massachusetts 02138 USA John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts 02138 USA Quantum Technology Center University of Maryland College Park Maryland 20742 USA Department of Electrical and Computer Engineering University of Maryland College Park Maryland 20742 USA Intelligence Community Postdoctoral Research Fellowship Program University of Maryland College Park Maryland 20742 USA Department of Physics University of Maryland College Park Maryland 20742 USA Department of Chemistry Technical University of Munich Lichtenbergstraße 4 85748 Garching Germany Department of Chemistry and Chemical Biology Harvard University Cambridge Massachusetts 02138 USA

We demonstrate quantum logic enhanced sensitivity for a macroscopic ensemble of solid-state, hybrid two-qubit sensors. We achieve over a factor of 30 improvement in the single-shot signal-to-noise ratio, translating to an ac magnetic field sensitivity enhancement exceeding an order of magnitude for time-averaged measurements. Using the electronic spins of nitrogen vacancy (NV) centers in diamond as sensors, we leverage the on-site nitrogen nuclear spins of the NV centers as memory qubits, in combination with homogeneous and stable bias and control fields, ensuring that all of the ∼109 two-qubit sensors are sufficiently identical to permit global control of the NV ensemble spin states. We find quantum logic sensitivity enhancement for multiple measurement protocols with varying optimal sensing intervals, including XY8 and DROID-60 dynamical decoupling, as well as correlation spectroscopy, using an applied ac magnetic field signal. The results are independent of the nature of the target signal and broadly applicable to measurements using NV centers and other solid-state spin ensembles. This work provides a benchmark for macroscopic ensembles of quantum sensors that employ quantum logic or quantum error correction algorithms for enhanced sensitivity.

关键词： NV centers Nuclear & electron resonance Quantum memories Quantum metrology Quantum sensing

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