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Fundamental bounds on the operation of Fano nonlinear isolators

Physical Review B 2018年第11期97卷 115431-115431页

作者： Dimitrios L. Sounas Andrea Alù 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 10031 USA Physics Program Graduate Center City University of New York New York 10016 USA Department of Electrical Engineering City College of The City University of New York New York 10031 USA

Nonlinear isolators have attracted significant attention for their ability to break reciprocity and provide isolation without the need of an external bias. A popular approach for the design of such devices is based on Fano resonators, which, due to their sharp frequency response, can lead to very large isolation for moderate input intensities. Here, we show that, independent of their specific implementation, these devices are subject to fundamental bounds on the transmission coefficient in the forward direction versus their quality factor, input power, and nonreciprocal intensity range. Our analysis quantifies a general tradeoff between forward transmission and these metrics, stemming directly from time-reversal symmetry, and that unitary transmission is only possible for vanishing nonreciprocity. Our results also shed light on the operation of resonant nonlinear isolators, reveal their fundamental limitations, and provide indications on how it is possible to design nonlinear isolators with optimal performance.

关键词： Electromagnetism Metamaterials Nonlinear optics

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Retracted: Implementation Method CUSUM to Determine the Accident Prone Areas in Web Based

Retracted: Implementation Method CUSUM to Determine the Acci...

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2018 Workshop on Multidisciplinary and Its Applications: Applied Mathematics, computer science, Information Systems, and Information Technology, WMA-Mathcomtech 2018

作者： Dinata, Rozzi Kesuma Abdullah, Dahlan Hartono, H. Erliana, Cut Ita Riasti, Berliana Kusuma Iskandar, Akbar Sari, Ifit Novita Nurmawati, N. Nanuru, Ricardo Freedom Putri, Lusi Dwi Manurung, Rosida Tiurma Sriadhi, S. Saleh, A.A. Astari, T. Khaddafi, Muammar Department of Informatics Universitas Malikussaleh Aceh Indonesia Department of Computer Science STMIK IBBI Medan Indonesia Department of Industrial Engineering Universitas Malikussaleh Aceh Indonesia Department of Informatics Universitas Sebelas Maret Surakarta Indonesia Department of Informatics STMIK AKBA Makassar Indonesia Departement Of: Social Science Education Program Post Graduate Program Universitas Kanjuruhan Malang Malang Indonesia Faculty of Industry Technique University of 45 Surabaya Indonesia Universitas Kristen Indonesia Maluku Ambon Indonesia Department of Civil Engineering Universitas Lancang Kuning Pekanbaru Indonesia Graduate Program in Scientific Psychology Universitas Kristen Maranatha Indonesia Department of Electrical Engineering Universitas Negeri Medan Indonesia Statistics Financial and Social Sciences Research Group Indonesia Department of Elementary School Teacher Education STKIP Citra Bangsa Aceh Utara Indonesia Department of Accounting Universitas Malikussaleh Aceh Indonesia

At the Unit Laka Lantas Polres Lhokseumawe determining accident-prone areas on roads in Lhokseumawe still using manual systems. Determination of accident-prone areas are less effective because the police Unit Laka Lantas Polres Lhokseumawe just using the data of the last year and had to repeatedly calculate manually accident-prone areas based on the number of human casualties. In this study the system implementation CUSUM method (Cummulative Summary) to determine the accident-prone areas designed using the web-based programming language PHP. In this system there are three processes to determine areas prone to accidents, the accident rate calculations based on the weighted severity, blacksite calculations using the Z-Score method for determining areas prone to accident blackspots and calculations using the CUSUM method to determine the critical points of an accident. The data used are secondary data obtained from the Police Unit Laka Lantas Polres Lhokseumawe years 2009-2013. © Published under licence by IOP Publishing Ltd.

关键词： Accidents

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A Comparative Study of the Ground State Transitions of CO and [C I] as Molecular Gas Tracers at High Redshift

arXiv

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arXiv 2024年

作者： Castillo, Marta Frias Rybak, Matus Hodge, Jacqueline A. van der Werf, Paul Smail, Ian Butterworth, Joshua Jansen, Jasper Topkaras, Theodoros Chen, Chian-Chou Chapman, Scott C. Weiss, Axel Algera, Hiddo Birkin, Jack E. da Cunha, Elisabete Chen, Jianhang Dannerbauer, Helmut Jiménez-Andrade, E.F. Ikarashi, Soh Liao, Cheng-Lin Murphy, Eric J. Swinbank, A.M. Walter, Fabian Rivera, Gabriela Calistro Ivison, R.J. Del Lagos, Claudia P. Leiden Observatory Leiden University P.O. Box 9513 Leiden2300 RA Netherlands Faculty of Electrical Engineering Mathematics and Computer Science Delft University of Technology Mekelweg 4 Delft2628 CD Netherlands SRON - Netherlands Institute for Space Research Niels Bohrweg 4 Leiden2333 CA Netherlands Centre for Extragalactic Astronomy Department of Physics Durham University South Road DurhamDH1 3LE United Kingdom I. Physikalisches Institut Universität zu Köln Zülpicher Str. 77 Köln50937 Germany No.1 Section 4 Roosevelt Road Taipei10617 Taiwan Department of Physics and Atmospheric Science Dalhousie University Halifax HalifaxNSB3H 3J5 Canada Max Planck Institut für Radioastronomie Auf dem Hügel 69 BonnD-53121 Germany Hiroshima Astrophysical Science Center Hiroshima University 1-3-1 Kagamiyama Hiroshima Higashi-Hiroshima739-8526 Japan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo Japan Department of Physics and Astronomy Texas A&M University 4242 TAMU College StationTX77843-4242 United States George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy Texas A&M University 4242 TAMU College StationTX77843-4242 United States International Centre for Radio Astronomy Research University of Western Australia 35 Stirling Hwy CrawleyWA6009 Australia Australia Karl-Schwarzschild-Straße 2 Garching bei München85748 Germany Tenerife La LagunaE-38205 Spain Dpto. Astrofísica Universidad de la Laguna Tenerife La LagunaE-38206 Spain Instituto de Radioastronomía y Astrofísica Universidad Nacional Autónoma de México Antigua Carretera a Pátzcuaro # 8701 Ex-Hda. San José de la Huerta Michoacán MoreliaC.P. 58089 Mexico Department of Physics General Studies College of Engineering Nihon University 1 Nakagawara Tokusada Tamuramachi Fukushima Koriyama963-8642 Japan National Astronomical Observatory of Japan 2-21-1 Osawa Mitaka Tokyo181-8588 Japan Graduate Institute of Astrophysics Na

The CO(1-0) and [C I](1-0) emission lines are well-established tracers of cold molecular gas mass in local galaxies. At high redshift, where the interstellar medium (ISM) is likely to be denser, there have been limited direct comparisons of both ground state transitions. Here we present a study of CO(1-0) and [C I](1-0) emission in a sample of 20 unlensed dusty, star-forming galaxies at z = 2 − 5. The CO(1-0)/[C I](1-0) ratio is constant up to at least z = 5, supporting the use of [CI](1-0) as a gas mass tracer. PDR modelling of the available data indicates a median H2 density of log(n [cm−3]) = 4.7 ± 0.2, and UV radiation field log(GUV [G0]) = 3.2 ± 0.2. We use the CO(1-0), [C I](1-0) and 3mm dust continuum measurements to cross-calibrate the respective gas mass conversion factors, finding no dependence of these factors on either redshift or infrared luminosity. Assuming a variable CO conversion factor then implies [C I] and dust conversion factors that differ from canonically assumed values but are consistent with the solar/super-solar metallicities expected for our sources. Radiative transfer modelling shows that the warmer CMB at high redshift can significantly affect the [C I] as well as CO emission, which can change the derived molecular gas masses by up to 70% for the coldest kinetic gas temperatures expected. Nevertheless, we show that the magnitude of the effect on the ratio of the tracers is within the known scatter of the L′CO − L′[CI] relation. Further determining the absolute decrease of individual line intensities will require well-sampled spectral line energy distributions (SLEDs) to model the gas excitation conditions in more detail. Copyright © 2024, The Authors. All rights reserved.

关键词： Ground state

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Deep learning on image denoising: An overview

arXiv

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arXiv 2019年

作者： Tian, Chunwei Fei, Lunke Zheng, Wenxian Xu, Yong Zuo, Wangmeng Lin, Chia-Wen Bio-Computing Research Center Harbin Institute of Technology Shenzhen Shenzhen Guangdong518055 China Shenzhen Key Laboratory of Visual Object Detection and Recognition Shenzhen Guangdong518055 China School of Computers Guangdong University of Technology Guangzhou Guangdong510006 China Tsinghua Shenzhen International Graduate School Shenzhen Guangdong518055 China Peng Cheng Laboratory Shenzhen Guangdong518055 China School of Computer Science and Technology Harbin Institute of Technology Harbin Heilongjiang150001 China Department of Electrical Engineering Institute of Communications Engineering National Tsing Hua University Hsinchu Taiwan

Deep learning techniques have obtained much attention in image denoising. However, deep learning methods of different types deal with the noise have enormous differences. Specifically, discriminative learning based on deep learning can well address the Gaussian noise. Optimization model methods based on deep learning have good effect on estimating of the real noise. So far, there are little related researches to summarize different deep learning techniques for image denoising. In this paper, we make such a comparative study of different deep techniques in image denoising. We first classify the (1) deep convolutional neural networks (CNNs) for additive white noisy images, (2) deep CNNs for real noisy images, (3) deep CNNs for blind denoising and (4) deep CNNs for hybrid noisy images, which is the combination of noisy, blurred and low-resolution images. Then, we analyze the motivations and principles of deep learning methods of different types. Next, we compare and verify the state-of-the-art methods on public denoising datasets in terms of quantitative and qualitative analysis. Finally, we point out some potential challenges and directions of future research. Copyright © 2019, The Authors. All rights reserved.

关键词： Deep neural networks

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Broadband Cyclic-Symmetric Magnet-less Circulatorsand Theoretical Bounds on their Bandwidth

arXiv

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arXiv 2018年

作者： Kord, Ahmed Sounas, Dimitrios L. Xiao, Zhicheng Alù, Andrea Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States Advanced Science Research Center Physics Program Graduate Center Photonics Initiative Department of Electrical Engineering City College of New York City University of New York New York NY10031 United States

In this paper, we explore theoretically and experimentally broadband spatiotemporally modulated (STM) magnet-less circulators realized by combining three-port non-reciprocal junctions with three identical bandpass filters. We develop a rigorous theory for the proposed circuit, which allows to optimize its design and to derive a global bound on the maximum possible bandwidth (BW). We verify our theory with simulations and measurements of a printed circuit board (PCB) prototype based on a differential wye junction and second-order Chebyshev bandpass filters, resulting in a measured fractional BW of 13.9% at a center frequency of 1 GHz. Copyright © 2018, The Authors. All rights reserved.

关键词： Bandwidth

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The complete mitogenome of Bagrid catfishChrysichthys nigrodigitatus(Siluriformes: Claroteidae)

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Mitochondrial DNA Part B 2018年第2期3卷 1239-1240页

作者： Nack-Keun Kim Fantong Zealous Gietbong Sapto Andriyono Ah Ran Kim Hyun-Woo Kim Interdisciplinary Program of Biomedical Mechanical and Electrical Engineering Pukyong National University Busan Republic of Korea Department of Marine Biology Pukyong National University Busan Republic of KoreaKOICA-PKNU International Graduate Program of Fisheries Science Graduate School of Global Fisheries Pukyong National University Busan Republic of Korea Interdisciplinary Program of Biomedical Mechanical and Electrical Engineering Pukyong National University Busan Republic of KoreaDepartment of Marine Fisheries and Marine Faculty Universitas Airlangga C Campus Jl. Mulyorejo Surabaya East Java Indonesia Department of Marine Biology Pukyong National University Busan Republic of Korea Interdisciplinary Program of Biomedical Mechanical and Electrical Engineering Pukyong National University Busan Republic of KoreaDepartment of Marine Biology Pukyong National University Busan Republic of Korea

We here report the complete mitochondrial genome ofChrysichthys nigrodigitatus, which is 16,514 bp in length. Mitogenome ofC. nigrodigitatusshowed the conserved 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and two noncoding regions including the light-strand replication origin (OL) and a putative control region (CR). All tRNA genes were predicted to fold into the typical cloverleaf secondary structures with the typical base-pairing except for tRNA-Ser(AGC). Phylogenetic analysis with currently known complete mitogenome sequences in Siluriformes showed thatC. nigrodigitatusis most closely related toAuchenoglanis occidentalisforming a family Claroteidae cluster.

关键词： Chrysichthys nigrodigitatus mitochondrial genome catfish Cameroon Africa

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Maximum Willis Coupling in Acoustic Scatterers

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Physical Review Letters 2018年第25期120卷 254301-254301页

作者： Li Quan Younes Ra’di Dimitrios L. Sounas Andrea Alù 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 Physics Program Graduate Center City University of New York New York New York 10026 USA Department of Electrical Engineering City College of New York New York New York 10031 USA

Willis coupling in acoustic materials defines the cross-coupling between strain and velocity, analogous to bianisotropic phenomena in electromagnetics. While these phenomena have been garnering significant attention in recent years, to date their effects have been considered mostly perturbative. Here, we derive general bounds on the Willis response of acoustic scatterers, show that these bounds can be reached in suitably designed scatterers, and outline a systematic venue for the realistic implementation of maximally bianisotropic acoustic inclusions. We then employ these inclusions to realize acoustic metasurfaces for bending and steering of sound with unitary efficiency.

关键词： Acoustic metamaterials Acoustic wave phenomena Acoustics Mechanical & acoustical properties

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Active Microwave Cloaking Using Parity-Time-Symmetric Satellites

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Physical Review Applied 2018年第5期10卷 054040-054040页

作者： Ahmed Kord Dimitrios L. Sounas Andrea Alù 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 Physics Program Graduate Center City University of New York New York New York 10026 USA Department of Electrical Engineering City College of New York New York New York 10031 USA

In this paper, we present and study the dynamics of an active microwave cloaking technique that alleviates the trade-offs between loss, bandwidth, and size inherent in passive approaches. The presented cloak consists of a finite number of satellite antennas loaded with parity-time-symmetric lumped admittances, which, without external control, can track in real time the amplitude, frequency, and phase variations of the impinging signals and generate the required current distributions at the antennas to totally suppress the scattered waves, including reflections and shadows. We analytically derive the optimal density and frequency dispersion of the antenna satellites surrounding the object in order to achieve substantial reduction in the scattering crosssection over a wide bandwidth. We also investigate the conditions necessary to maintain the cloak stability and study its transient response for excitation with pulsed signals.

关键词： Cloaking Metamaterials Optical cloaking PT-symmetry Microwave techniques

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Anisotropic superconductivity and frozen electronic states at the (111) LaAlO3/SrTiO3 interface

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Physical Review B 2018年第2期98卷 024504-024504页

作者： S. Davis Z. Huang K. Han Ariando T. Venkatesan V. Chandrasekhar Graduate Program in Applied Physics and Department of Physics and Astronomy Northwestern University 2145 Sheridan Road Evanston Illinois 60208 USA NUSNNI-Nanocore National University of Singapore 117411 Singapore Department of Physics National University of Singapore 117551 Singapore NUS Graduate School for Integrative Sciences & Engineering National University of Singapore 117456 Singapore Department of Physics National University of Singapore 117542 Singapore Department of Electrical and Computer Engineering National University of Singapore 117576 Singapore Department of Material Science and Engineering National University of Singapore 117575 Singapore

We report measurements of the superconducting properties of the two-dimensional (2D) gas that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) in the (111) crystal orientation, a system that permits in situ tuning of carrier density and disorder by means of a back-gate voltage Vg. Like the (001) oriented LAO/STO interface, superconductivity at the (111) LAO/STO interface can be tuned by Vg. The 2D superconductivity in these (111) LAO/STO samples shows an in-plane anisotropy, being different along different interface crystal directions, and “remembers” the disorder landscape at which they are cooled through the superconducting transition. The low energy scale and other characteristics of this memory effect distinguish it from charge-trapping effects previously observed in (001) interface samples.

关键词： electrical conductivity Impurities in superconductors Superconducting phase transition Superconductivity Interfaces Solid-solid interfaces Superconductors Two-dimensional electron gas Type-II superconductors Hall bar Resistivity measurements

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Signatures of electronic nematicity in (111) LaAlO3/SrTiO3 interfaces

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Physical Review B 2018年第4期97卷 041408(R)-041408(R)页

作者： S. Davis Z. Huang K. Han Ariando T. Venkatesan V. Chandrasekhar Graduate Program in Applied Physics and Department of Physics and Astronomy Northwestern University 2145 Sheridan Road Evanston Illinois 60208 USA NUSNNI-Nanocore National University of Singapore 117411 Singapore Department of Physics National University of Singapore 117551 Singapore NUS Graduate School for Integrative Sciences & Engineering National University of Singapore 117456 Singapore Department of Electrical and Computer Engineering National University of Singapore 117576 Singapore Department of Material Science and Engineering National University of Singapore 117575 Singapore

The two-dimensional conducting gas (2DCG) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has been widely studied due to the multitude of in situ tunable phenomena that exist at the interface. Recently it has been shown that nearly every property of the 2DEG that forms at the interface of (111) oriented LAO/STO is strongly anisotropic with respect to the in-plane crystal direction. This in-plane rotational symmetry breaking points to the existence of an electronic nematic phase at the interface that can be modified by an in situ electrostatic back-gate potential. Here we show that the onset temperature of the anisotropy in the longitudinal resistance is T≈22K, which does not match up with any known structural transition, and coincides with the onset of anisotropy in the Hall response of the system. Furthermore, below 22 K, charge transport is activated in nature with different activation energies along the two in-plane crystal directions. Such a response implies that the band edges along the two directions are different and provides further evidence of an electronic nematic state at the interface.

关键词： electrical properties Hall effect Nematic order Transport phenomena Hall bar Resistivity measurements Transport techniques

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