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Reply to “Comment on ‘Scattering Cancellation-Based Cloaking for the Maxwell-Cattaneo Heat Waves’”

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Physical Review Applied 2021年第5期15卷 058002-058002页

作者： M. Farhat S. Guenneau P.-Y. Chen A. Alù K.N. Salama Computer Electrical and Mathematical Science and Engineering (CEMSE) Division King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia UMI 2004 Abraham de Moivre-CNRS Imperial College London London SW7 2AZ United Kingdom Department of Electrical and Computer Engineering University of Illinois at Chicago Chicago Illinois 60607 USA Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA

Spectral DiffuserCam: lensless snapshot hyperspectral imaging with a spectral filter array

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arXiv 2020年

作者： Monakhova, Kristina Yanny, Kyrollos Aggarwal, Neerja Waller, Laura Department of Electrical Engineering & Computer Sciences University of California BerkeleyCA94720 United States UCB/UCSF Joint Graduate Program in Bioengineering University of California BerkeleyCA94720 United States

Hyperspectral imaging is useful for applications ranging from medical diagnostics to crop monitoring;however, traditional scanning hyperspectral imagers are prohibitively slow and expensive for widespread adoption. Snapshot techniques exist but are often confined to bulky bench-top setups or have low spatio-spectral resolution. In this paper, we propose a novel, compact, and inexpensive computational camera for snapshot hyperspectral imaging. Our system consists of a repeated spectral filter array placed directly on the image sensor and a diffuser placed close to the sensor. Each point in the world maps to a unique pseudorandom pattern on the spectral filter array, which encodes multiplexed spatio-spectral information. A sparsity-constrained inverse problem solver then recovers the hyperspectral volume with good spatio-spectral resolution. By using a spectral filter array, our hyperspectral imaging framework is flexible and can be designed with contiguous or non-contiguous spectral filters that can be chosen for a given application. We provide theory for system design, demonstrate a prototype device, and present experimental results with high spatio-spectral resolution. © 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement Copyright © 2020, The Authors. All rights reserved.

关键词： Spectroscopy

Scalable Metagrating for Efficient Ultrasonic Focusing

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Physical Review Applied 2021年第6期16卷 064014-064014页

作者： Yan Kei Chiang Li Quan Yugui Peng Shahrokh Sepehrirahnama Sebastian Oberst Andrea Alù David A. Powell School of Engineering and Information Technology University of New South Wales Canberra ACT 2610 Australia Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Centre for Audio Acoustics and Vibration University of Technology Sydney Broadway NSW 2007 Australia Physics Program Graduate Center City University of New York New York New York 10016 USA

Acoustic metalenses have been pursued over the past decades due to their pivotal role in a wide variety of applications. Recent research efforts have demonstrated that, at ultrasonic regimes, acoustic levitation can be realized with standing waves, which are created by the interference between incoming and reflected focused waves. However, the conventional gradient-metasurface approach to focus ultrasonic waves is complex, leading to poor scalability. In this work, we propose a design principle for ultrasonic metalenses, based on metagratings—arrays of discrete scatters with coarser features than gradient metasurfaces. We achieve beam focusing by locally controlling the excitation of a single diffraction order with the use of metagratings, with geometry adiabatically varying over the lens aperture. We show that our metalens can effectively focus impinging ultrasonic waves to a focal point with a full width at half maximum of 0.364 of the wavelength. The focusing performance of the metalens is demonstrated experimentally, validating our proposed approach. This metagrating approach to focusing can be adopted for different operating frequencies by scaling the size of the structure, which has coarse features suitable for high-frequency designs, with potential applications ranging from biomedical science to nondestructive testing.

关键词： Acoustic measurements Acoustic metamaterials Acoustic modeling Acoustic wave phenomena Beam optics Ultrasonics Bloch-Floquet theorem Ultrasound techniques

Realizing and Experimentally Testing a Reluctance-Based Magnetic Lead Screw

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Realizing and Experimentally Testing a Reluctance-Based Magn...

International Symposium on Electromagnetic Fields in Mechatronics, electrical and Electronic engineering (ISEF) Book of Abstracts

作者： Mateus Cirolini Aly Ferreira Flores Filho Paulo Roberto Eckert Lucas Dalla Corte Franchi Post-Graduate Program in Electrical Engineering Federal University of Rio Grande do Sul Porto Alegre Brazil

ISBN: (数字)9781728115603

ISBN: (纸本)9781728115610

This paper presents the realization and the experimental tests of a new type of reluctance-based magnetic lead screw (RBMLS) that is attractive for many potential applications. The proposed topology presents structure simplification with the implementation of discretized permanent magnets (PM) and ferromagnetic semi-rings. The proposed RBMLS has PMs only in one of its movable parts, making it suitable for long-stroke applications. The dynamic experimental results for the realized prototype are going to be compared to the 3-D finite-element method (FEM) outcomes. Experimental static results have already been obtained and show good agreement.

关键词： Fasteners Lead Rotors Topology Magnetic resonance imaging Force Magnetic flux

Direct Torque Control Scheme for a Nine-Phase Induction Motor With Reduced Current Harmonic

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Direct Torque Control Scheme for a Nine-Phase Induction Moto...

Brazilian Power Electronics Conference, COBEP

作者： Gilielson F. da Paz Isaac S. de Freitas Victor F. M. B. Melo Alexandre G. F. da Silva Post-Graduate Program in Electrical Engineering - PPgEE UFPB Federal University of Paraíba Paraíba Brazil

ISBN: (数字)9781728141800

ISBN: (纸本)9781728141817

This paper discusses a modified Direct Torque Control (DTC) method in order to reduce phase current harmonic distortion in a nine-phase asymmetrical induction motor drive system. Since the classical DTC is a direct adaptation from the three-phase case, it does not take into account the presence of the non-producing torque current components obtained from the Space Vector Decomposition (SVD) technique. Thus, in classical DTC these non-producing torque components assume high amplitudes, causing distortion in phase currents. In this way, it is shown that modified DTC minimizes the undesired components, reducing significantly the distortion in phase currents while maintaining the fast dynamic response of classical DTC.

关键词： Torque Stators Switches Harmonic distortion Rotors Torque control

Identifying Materials-Level Sources of Performance Variation in Superconducting Transmon Qubits

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arXiv 2025年

作者： Murthy, Akshay A. Bal, Mustafa Bedzyk, Michael J. Cansizoglu, Hilal Chan, Randall K. Chandrasekhar, Venkat Crisa, Francesco Datta, Amlan Deng, Yanpei Matute Diaz, Celeo D. Dravid, Vinayak P. Garcia-Wetten, David A. Garattoni, Sabrina Ghimire, Sunil Goronzy, Dominic P. de Graaf, Sebastian E. Haeuser, Sam Hersam, Mark C. Isheim, Dieter Joshi, Kamal Kim, Richard Kolachina, Saagar Kopas, Cameron J. Kramer, Matthew J. Lachman, Ella O. Lee, Jaeyel Lim, Peter G. Lunin, Andrei Mah, William Marshall, Jayss Mutus, Josh Y. Oh, Jin-Su Pappas, David P. Park, Joong-Mok Prozorov, Ruslan dos Reis, Roberto Seidman, David N. Sung, Zuhawn Tanatar, Makariy Walker, Mitchell J. Wang, Jigang Wu, Haotian Zhou, Lin Zhu, Shaojiang Grassellino, Anna Romanenko, Alexander BataviaIL60510 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Rigetti Computing BerkeleyCA94710 United States Ames National Laboratory AmesIA50011 United States Department of Physics & Astronomy Iowa State University AmesIA50011 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States The NUANCE Center Northwestern University EvanstonIL60208 United States International Institute of Nanotechnology Northwestern University EvanstonIL60208 United States National Physical Laboratory TeddingtonTW11 0LW United Kingdom Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States Applied Physics Graduate Program Northwestern University EvanstonIL60208 United States Department of Materials Science and Engineering Iowa State University AmesIA50011 United States

The Superconducting Materials and Systems (SQMS) Center, a DOE National Quantum Information Science Research Center, has conducted a comprehensive and coordinated study using superconducting transmon qubit chips with known performance metrics to identify the underlying materials-level sources of device-to-device performance variation. Following qubit coherence measurements, these qubits of varying base superconducting metals and substrates have been examined with various nondestructive and invasive material characterization techniques at Northwestern University, Ames National Laboratory, and Fermilab as part of a blind study. We find trends in variations of the depth of the etched substrate trench, the thickness of the surface oxide, and the geometry of the sidewall, which when combined, lead to correlations with the T1 lifetime across different devices. In addition, we provide a list of features that varied from device to device, for which the impact on performance requires further studies. Finally, we identify two low-temperature characterization techniques that may potentially serve as proxy tools for qubit measurements. These insights provide materials-oriented solutions to not only reduce performance variations across neighboring devices, but also to engineer and fabricate devices with optimal geometries to achieve performance metrics beyond the state-of-the-art values. © 2025, CC BY.

关键词： Qubits

Terahertz chiral photonic-crystal cavities with broken time-reversal symmetry

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arXiv 2024年

作者： Tay, Fuyang Sanders, Stephen Baydin, Andrey Song, Zhigang Welakuh, Davis M. Alabastri, Alessandro Rokaj, Vasil Dag, Ceren B. Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley–Curl Institute Rice University HoustonTX77005 United States Smalley–Curl Institute Rice University HoustonTX77005 United States John A. Paulson School of Engineering and Applied Sciences Harvard University CambridgeMA02139 United States Max Planck Institute for The Structure and Dynamics of Matter Luruper Chaussee 149 Hamburg22761 Germany ITAMP Harvard-Smithsonian Center for Astrophysics CambridgeMA02138 United States Department of Physics Harvard University CambridgeMA02138 United States Department of Physics Villanova University VillanovaPA19085 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Strong coupling between matter and vacuum electromagnetic fields in a cavity can induce novel quantum phases in thermal equilibrium via symmetry breaking. Particularly, coupling with circularly polarized fields can break time-reversal symmetry, leading to topological modifications in the band structure. Therefore, chiral optical cavities that host chiral vacuum fields are being sought, especially in the terahertz (THz) frequency range, where various large-oscillator-strength resonances exist. Here, we present a novel approach to achieving THz chiral photonic-crystal cavities (PCCs) with high-quality factors (>400) using a magnetoplasma in a lightly doped semiconductor. Numerical simulations of an optimized structure based on InSb in a small perpendicular magnetic field (∼0.2 T) show chiral cavity resonances with near-perfect ellipticity at the surfaces of the central dielectric layer, where one can place atomically thin materials like monolayer graphene. We theoretically estimate an energy gap on the order of 1 meV in graphene when coupled to our proposed chiral cavity, which is potentially measurable in experiments. These THz chiral PCCs offer a promising platform for exploring new phases in cavity-dressed condensed matter with broken time-reversal symmetry. Copyright © 2024, The Authors. All rights reserved.

关键词： Crystal symmetry

High Impedance Fault Detection based on Stockwell Transform

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High Impedance Fault Detection based on Stockwell Transform

2018 IEEE PES Transmission and Distribution Conference and Exhibition - Latin America, T and D-LA

作者： Lima, Erica Mangueira De Almeida Coelho, Rodrigo Brito, Nubia Silva Dantas Alencar De Souza, Benemar Electrical Engineering Post Graduate Program Federal University of Campina Grande Campina Grande Brazil

ISBN: (纸本)9781538658444

A high impedance fault (HIF) detection method is proposed in this paper. Several parameters are extracted using the Stockwell transform, which is a relatively new multi-resolution tool with the ability to provide good resolution on both time and frequency domain, simultaneously. Those parameters are used to identify a HIF occurrence and distinguish it from other common disturbances such as capacitor banks switching, feeder energizing and solid faults. Two databases are used to validate the method, one with simulated data and one with real HIF oscillographic records, obtained from field experiments. A brief analysis of parameters behavior is also presented, since it is necessary for method's development. Results show the method is able to detect HIF on both simulated and real data in viable time, using only the substation as observation point. Also it can distinguish the fault from other tested disturbances. © 2018 IEEE.

关键词： Frequency domain analysis

Response to Comment on (Novel two-dimensional porous graphitic carbon nitride C6N7 monolayer: A First-principle calculations [Appl. Phys. Lett. 2021, 119, 142102])

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arXiv 2022年

作者： Bafekry, Asadollah Faraji, Mehrdad Fadlallah, Mohamed M. Sarsari, I. Abdolhosseini Jappor, Hamad R. Fazeli, Sara Ghergherehchi, Mitra Department of Radiation Application Shahid Beheshti University Tehran Iran Micro and Nanotechnology Graduate Program TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey Department of Physics Faculty of Science Benha University Benha13518 Egypt Department of Physics Isfahan University of Technology Isfahan84156-83111 Iran Department of Physics College of Education for Pure Sciences University of Babylon Hilla Iraq Department of Material Science and Engineering Sharif University of Technology PO Box 11155-9466 Tehran Iran Department of Electrical and Computer Engineering Sungkyunkwan University Suwon16419 Korea Republic of

Recently, reported a comments on the our paper [Appl. Phys. Lett. 119, 142102(2021)]. With our response, the APL journal rejected their non scientificcomments. There are some ambiguities about their claim: 1-They can check thephonon dispersion of their structure to see ZA out-of-plane mode. 2-They reportthe uniaxial stress-strain responses in Fig 2., which is unrelated to ourpaper. For a more helpful understanding of the mechanical properties of thenovel C6N7 monolayer, they can publish a paper. 3-They mentioned: Using the DFTmethod and with assuming a thickness of 3.35 A for the C6N7 monolayer based ongraphene thickness. Why did they choose this thickness while we know our C6N7monolayer is at without buckling? The distance of ZA out-of-plane movement ofions in C6N7 is different from Graphene. © 2022, CC BY.

关键词： Monolayers