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133rd Audio Engineering Society Convention 2012, AES 2012

作者： Xie, Bo-Sun Shi, Bei Xiang, Ning Physics Dept. School of Science South China University of Technology Guangzhou 510641 China Graduate Program in Architectural Acoustics Rensselaer Polytechnic Institute School of Architecture 12180 Troy NY United States

ISBN: (纸本)9781622766031

An algorithm of audio signal dccorrclation is proposed. The algorithm is based on a pair of all-pass filters whose responses match with a pair of reciprocal maximal length sequences (MLSs). Taking advantage of the characters of uniform power spectrum and low-valued cross-correlation of reciprocal MLSs, the filters create a pair of output signals with low cross-correlation but almost identical magnitude spectra to the input signal. The proposed algorithm is applied to broadening the auditory source-width and enhancing subjective envelopment in multichannel sound reproduction. Preliminary psychoacoustic experiments validate the performance of the proposed algorithm.

关键词： Bandpass filters

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Ultrahigh zT from strong electron-phonon interactions and a low-dimensional Fermi surface

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Energy and Environmental science 2024年第5期17卷 1904-1915页

作者： Ranganayakulu, V.K. Wang, Te-Hsien Chen, Cheng-Lung Huang, Angus Ma, Ma-Hsuan Wu, Chun-Min Tsai, Wei-Han Hung, Tsu-Lien Ou, Min-Nan Jeng, Horng-Tay Lee, Chih-Hao Chen, Kuei-Hsien Li, Wen-Hsien Brod, Madison K. Snyder, G. Jeffrey Chen, Yang-Yuan Institute of Physics Academia Sinica Taipei11529 Taiwan Department of Engineering and System Science National Tsing Hua University Hsinchu30013 Taiwan Taiwan International Graduate Program Taipei11529 Taiwan Department of Physics National Chung Hsing University Taichung City40227 Taiwan Graduate School of Materials Science National Yunlin University of Science and Technology Yunlin64002 Taiwan Bachelor Program in Semiconductor Materials and Fabrication Ming Chi University of Technology New Taipei City243303 Taiwan Department of Physics National Tsing Hua University Hsinchu30013 Taiwan Center for Theory and Computation National Tsing Hua University Hsinchu30013 Taiwan Physics Division National Center for Theoretical Sciences Taipei10617 Taiwan Department of Physics National Central University Jhongli32001 Taiwan National Synchrotron Radiation Research Center Hsinchu Science Park Hsinchu30076 Taiwan Institute of Atomic and Molecular Sciences Academia Sinica Taipei10617 Taiwan Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Graduate Institute of Applied Physics National Chengchi University Taipei11605 Taiwan

The outstanding thermoelectric performance of GeTe has attracted significant attention in the research community in recent years. However, many of the underlying physical mechanisms that contribute to GeTe's exceptionally high figure of merit (zT) remain not fully understood. In this study, an Sb-Bi codoped GeTe single crystal (Ge0.86Sb0.08Bi0.06)Te with an ultrahigh zT of 2.7 at 700 K and a record high device zT of 1.41 in the temperature range of 300-773 K was synthesized and investigated. The ultrahigh zT is attributed to the extremely low lattice thermal conductivity induced by strong electron-phonon (EP) interactions as revealed by the experimentally observed Kohn anomaly, through inelastic neutron scattering (INS) measurements. First-principles calculations further demonstrate that the remarkable EP interaction arises from the Fermi surface nesting featured in a one-dimensional (double-walled) topology. Our finding unravels the ultrahigh-zT mechanism in GeTe-based materials, serving as an inspiring guide toward high thermoelectric performance. © 2024 The Royal Society of Chemistry.

关键词： Neutron scattering

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Investigation of Overcoming the Chu Lower Bound on Quality Factor for Antennas Tuned with Highly Dispersive Lossy Material 22

Investigation of Overcoming the Chu Lower Bound on Quality F...

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22nd International Conference on Electromagnetics in Advanced Applications, ICEAA 2021

作者： Ra'di, Younes Alu, Andrea City University of New York Advanced Science Research Center Photonics Initiative NY10031 United States City University of New York Physics Program Graduate Center NY10016 United States

ISBN: (纸本)9781665413862

The quality factor of an antenna is a powerful quantity that usually provides a good sense of its bandwidth helping antenna designers to evaluate the overall performance. The fundamental relationships between impedance, bandwidth, and Q factor of antennas have always been one of the most important and exciting research topics benefitting both theoretical and applied electromagnetics [1]. © 2021 IEEE.

关键词： Antennas

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AI-Based Intelligent-Annotation Algorithm for Medical Segmentation from Ultrasound Data 20th

AI-Based Intelligent-Annotation Algorithm for Medical Segmen...

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20th Pacific Rim International Conference on Artificial Intelligence, PRICAI 2023

作者： Peng, Tao Zhang, Yaogong Dong, Yan Ruan, Yiwen Jin, Rui Liu, Zhaorui Wu, Hongzhuang Shen, Yuling Zhang, Lei School of Future Science and Engineering Soochow University Suzhou China Medical Physics Graduate Program and Data Science Research Center Duke Kunshan University Jiangsu Kunshan China Department of Ultrasonography The First Affiliated Hospital of Soochow University Suzhou China

ISBN: (纸本)9789819970247

The management of prostate cancer, a prevalent source of mortality in men, calls for meticulous delineation of the prostate in transrectal ultrasound (TRUS) images for effective treatment planning. This paper introduces a hybrid artificial intelligence approach for prostate delineation, leveraging prior information from experts, a machine learning model, and a quantum-inspired evolutionary network to augment the accuracy of prostate segmentation. The approach incorporates three novel elements: 1) limited prior information from expert and adaptive polygon tracking (APT) module for initial segmentation;2) a novel historical storage-based quantum-inspired evolutionary network (HQIE) mechanism to search for the optimal neural network and enhancing solution diversity and capacity to address unimodal and multimodal challenges, and 3) a unique mathematical formulation denoted by parameters of the neural network is used to achieve smooth prostate periphery. The method was evaluated across various noise conditions and against several state-of-the-art methods using a multi-center dataset. In addition, an ablation study was performed to evaluate the efficacy of each component. The results demonstrated the superior performance of the hybrid AI method (Dice index: 96.4 ± 2.4%) against state-of-the-art deep learning methods (e.g., UTNet, Dice index: 90.1 ± 5.7%). The hybrid method also showed higher robustness to image noise than traditional methods. This study suggests new insights and technical approaches in the field of prostate segmentation using hybrid artificial intelligence methods. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2024.

关键词： Ultrasonics

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Performance Evaluation of "XRPIX" Event-Driven SOI Pixel Detector for Cosmic MeV Gamma-ray Observation 38

Performance Evaluation of "XRPIX" Event-Driven SOI Pixel Det...

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38th International Cosmic Ray Conference, ICRC 2023

作者： Hashizume, Masaki Suda, Yusuke Fukazawa, Yasushi Tsuru, Takeshi Go Takeda, Ayaki Physics Program Graduate School of Advanced Science and Engineering Hiroshima University 1-3-1 Kagamiyama Higashi-Hiroshima Hiroshima Japan Kyoto University Graduate School of Science Yoshida-Honmachi Sakyo-ku Kyoto Japan University of Miyazaki Department of Technology 1-1 Gakuen Kibanadai-nishi Miyazaki Japan

Cosmic MeV gamma-ray observations are important for elucidating physics in high-energy objects such as gamma-ray bursts and active galactic nuclear jet blazars, for detecting nuclear gamma-rays in supernova explosions, and for advancing multi-messenger astronomy. However, there has been no progress since the COMPTEL detector on board the CGRO satellites in the 1990s, and a satellite for MeV gamma-ray observations is essential. Compton scattering is the dominant interaction between MeV gamma-rays and matter. The minimal way to reconstruct the arrival direction of an incident gamma-ray is to utilize both the deposit energy and hit position measured in both the scatterer and absorber, giving an event circle. The circle can be reduced to an arc if the initial direction of the Compton scattered electron is measured. Thus such an electron-tracking Compton camera is expected to improve the source sensitivity by reducing background events. Therefore, our goal is to enable more accurate Compton imaging by using an event-driven SOI pixel detector "XRPIX" as a scatterer in an electron-track Compton camera. The pixel size of XRPIX is as small as 36 um square, so it is expected to capture electron trajectories for scattering of gamma-rays of several hundred keV. In this contribution, we report on the evaluation of the depletion layer thickness of XRPIX8.5, which can be fully depleted at room temperature, the sensor response when irradiated with gamma-rays such as 662 keV of Cs-137 and 511 keV of Na-22, and a method for estimating the direction of scattered electrons. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmology

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Accuracy of DFT computed oxygen-vacancy formation energies and high-throughput search of solar thermochemical water-splitting compounds

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Physical Review Materials 2023年第6期7卷 065403-065403页

作者： Bianca Baldassarri Jiangang He Xin Qian Emanuela Mastronardo Sean Griesemer Sossina M. Haile Christopher Wolverton Graduate Program in Applied Physics Northwestern University Evanston Illinois USA Department of Materials Science and Engineering Northwestern University Evanston Illinois USA

The enthalpy change involved in metal oxide reduction is a key quantity in various processes related to energy conversion and storage and is of particular interest for computational prediction. Often this prediction involves the simulation of a high-temperature reduction process with a 0-K methodology like density functional theory (DFT), and it is not infrequent for the high temperature and 0-K stable crystal structures to differ. This introduces a conundrum with regard to the choice of crystal structure to utilize in the computation, with approaches in the literature varying and experimental validation remaining scarce. In this work, we address both the crystal structure conundrum and the experimental validation, and then apply the insights we gain to guide a high-throughput search for new materials for solar thermochemical water-splitting applications. By computing the DFT+U oxygen-vacancy formation energy (ΔEvf) of a selection of ABO3 compounds and comparing different crystal structures for each composition, we highlight the issues that arise when the structure utilized in the computation is dynamically unstable at 0 K, namely the presence of an artificial lowering of ΔEvf, and the lack of convergence of ΔEvf with cell size. We solve these limitations by identifying and employing a suitable surrogate dynamically stable structure. We then validate the predictive power of our calculations against appositely generated experimental measurements of reduction enthalpy for a series of Hubbard U values, finding an accuracy ranging between 0.2–0.6 eV/O. In light of such conclusions, we revise and expand a previous a high-throughput DFT study on ABO3 perovskite oxides. We provide a list of candidate STCH materials, highlight trends with redox-active cation and structural distortion, and identify Mn4+, Mn3+, and Co3+ as the most promising redox-active cations.

关键词： Energy applications First-principles calculations Hydrogen energy

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Lumen loaded of kenaf pulp with magnetic pigment

Lumen loaded of kenaf pulp with magnetic pigment

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59th Appita Annual Conference and Exhibition, incorporating the 13th ISWFPC: International Symposium on Wood, Fibre and Pulping Chemistry

作者： Zakaria, Sarani Hoong, Ong Boon Ahmad, Sahrim Hj. Abdullah, Mustaffc Hj. Van De Ven, T.G.M. Yamauchi, Tatsuo Materilsl Science Program School of Applied Physics Universiti Kebangsaan Malaysia 43600 Bangi Malaysia Pulp and Paper Research Center McGill University Montreal Canada Graduate School Faculty of Agricultre Kyoto University Kyoto

Lumen-loading technology allows filler particles to be introduced exclusively into the lumens of the fibres while leaving the external surfaces free of filler. This study focuses on the development of lumen-loading process for the preparation of magnetic pulp. Magnetic pulp was prepared from unbleached kraft pulp lumen-loaded with magnetite (Fe3O4). Cationic polyethylenimine (PEI) or alum as retention aids in the lumen-loading process produced a better retention of the pigments in the preparation of this magnetic pulp. The physical properties of loading pup showed a decreased value as the filler content increased. The SEM picture showed the deposition of filler in the lumen.

关键词： Kenaf fibers

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Excitations in layered materials from a non-empirical Wannier-localized optimally-tuned screened rangeseparated hybrid functional

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npj Computational Materials 2024年第1期10卷 132-140页

作者： María Camarasa-Gómez Stephen E.Gant Guy Ohad Jeffrey B.Neaton Ashwin Ramasubramaniam Leeor Kronik Department of Molecular Chemistry and Materials Science Weizmann Institute of ScienceRehovoth7610001Israel Department of Physics University of CaliforniaBerkeleyCA94720USA Materials Sciences Division Lawrence Berkeley National LaboratoryBerkeleyCA94720USA Kavli Energy NanoSciences Institute at Berkeley University of CaliforniaBerkeleyCA94720USA Department of Mechanical and Industrial Engineering University of Massachusetts AmherstAmherstMA01003USA Materials Science and Engineering Graduate Program University of MassachusettsAmherstAmherstMA01003USA

Accurate prediction of electronic and optical excitations in van der Waals(vdW)materials is a long-standing challenge for density functional *** recent Wannier-localized optimally-tuned screened range-separated hybrid(WOT-SRSH)functional has proven successful in non-empirical determination of electronic band gaps and optical absorption spectra for covalent and ionic ***,for vdW materials the tuning of the material-and structure-dependent functional parameters has only been attained ***,we present a non-empirical WOT-SRSH approach applicable to vdW materials,with the optimal functional parameters transferable between monolayer and *** apply this methodology to prototypical vdW materials:black phosphorus,molybdenum disulfide,and hexagonal boron nitride(in the latter case including zero-point renormalization).We show that the WOT-SRSH approach consistently achieves accuracy levels comparable to experiments and many-body perturbation theory(MBPT)calculations for band structures and optical absorption spectra,both on its own and as an optimal starting point for MBPT calculations.

关键词： theory optimal functional

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Wavefront-selective Fano resonant metasurfaces

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Advanced Photonics 2021年第2期3卷 78-88页

作者： Adam Overvig Andrea Alù City University of New York Advanced Science Research CenterPhotonics InitiativeNew YorkUnited States City University of New York Graduate CenterPhysics ProgramNew YorkUnited States

Fano resonances are conventionally understood as sharp spectral features with selectivity in the momentum-frequency domain,implying that they can be excited only by plane waves with specific frequencies and incident *** demonstrate that Fano resonances can be made generally selective in the spacefrequency *** can be tailored to resonate only when excited by a frequency,polarization,and wavefront of *** generalization reveals that Fano systems are characterized by eigenwaves that scatter to their time-reversed image upon *** in conventional Fano systems this trivially occurs for normally incident plane waves,we show that,in general,the selected wavefront is locally retroreflected everywhere across the *** results show that conventional Fano resonances are a subset of a broader dichroic phenomenon with spin,spatial,and spectral *** demonstrate these concepts with nonlocal metasurfaces whose governing principles are deeply rooted in the symmetry features of quasi-bound states in the *** light–matter interactions and symmetry-protection make these phenomena uniquely suited for enriching applications in quantum optics,non-linear optics,augmented reality,and secure optical communications,laying the groundwork for a range of novel compact optical sources and devices.

关键词： nonlocal metasurface Fano resonance spatial selectivity quasi-bound states in the continuum

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Photoluminescence of CdSe/ZnS quantum dots in GaN/quantum dots/GaN wafer bonded system

Photoluminescence of CdSe/ZnS quantum dots in GaN/quantum do...

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作者： Li, Y. Giles, A. Stokes, E. Optical Science and Engineering Graduate Program Department of Physics and Optical Science University of North Carolina at Charlotte 9201 University City Boulevard Charlotte NC 28223 United States Nanoscale Science Graduate Program Department of Chemistry University of North Carolina at Charlotte 9201 University City Boulevard Charlotte NC 28223 United States Department of Electrical and Computer Engineering University of North Carolina at Charlotte 9201 University City Boulevard Charlotte NC 28223 United States

ISBN: (纸本)9781607681908

Wafer bonding technology is applied to the GaN/quantum dots/GaN system, where CdSe/ZnS Quantum Dots serve as both the active layer and the binding layer. Photoluminescence is observed from quantum dots following wafer bonding at various temperatures under ultra high vacuum condition. Temperature dependences of bond strength and photoluminescence properties are characterized. Annealing at elevated temperature to form wafer bonds degrades photoluminescence intensity and slightly blue shifts the wavelength. Transmission Electron Microscopy is applied to study the physical properties of vacuum annealed QDs, in which agglomeration is observed. ©The Electrochemical Society.

关键词： Gallium nitride

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