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arXiv 2021年

作者： Abdollahramezani, Sajjad Hemmatyar, Omid Taghinejad, Mohammad Taghinejad, Hossein Krasnok, Alex Eftekhar, Ali A. Teichrib, Christian Deshmukh, Sanchit El-Sayed, Mostafa Pop, Eric Wuttig, Matthias Alù, Andrea Cai, Wenshan Adibi, Ali School of Electrical and Computer Engineering Georgia Institute of Technology 778 Atlantic Drive NW AtlantaGA30332-0250 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical Engineering Precourt Institute for Energy Stanford University StanfordCA94305 United States Laser Dynamics Laboratory School of Chemistry and Biochemistry Georgia Institute of Technology AtlantaGA30332-0400 United States George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology AtlantaGA30332-0405 United States Physikalisches Institut IA RWTH Aachen Sommerfeldstrasse 14 Aachen52074 Germany Physics Program Graduate Center City University of New York New YorkNY10016 United States School of Materials Science and Engineering Georgia Institute of Technology 801 Ferst Drive NW AtlantaGA30332-0295 United States

Despite recent advances in active metaoptics, efficient wide dynamic range combined with highspeed reconfigurable solutions is still elusive. Phase-change materials (PCMs) offer a compelling platform for metasurface optical elements, owing to the large index contrast and fast yet stable phase transition properties. Here, we experimentally demonstrate an in situ electrically driven reprogrammable metasurface by harnessing the unique properties of a phase-change chalcogenide alloy, Ge2Sb2Te5 (GST), in order to realize non-volatile, reversible, multilevel, fast, and pronounced optical modulation in the near-infrared spectral range. Co-optimized through a multiphysics analysis, we integrate an efficient heterostructure resistive microheater that indirectly heats and transforms the embedded GST film without compromising the optical performance of the metasurface even after several reversible phase transitions. A hybrid plasmonic-PCM meta-switch with a record eleven-fold change in the reectance (an absolute reectance contrast reaching 80%), unprecedented quasi-continuous spectral tuning over 250 nm, and operation speed that can potentially reach a few kHz is presented. Our work represents a significant step towards the development of fully integrable dynamic metasurfaces and their potential for beamforming applications. © 2021, CC BY.

关键词： Phase change materials

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Reconfigurable Hyperbolic Polaritonics with Correlated Oxide Metasurfaces

Research Square

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Research Square 2021年

作者： Aghamiri, Neda Alsadat Hu, Guangwei Fali, Alireza Zhang, Zhen Li, Jiahan Balendhran, Sivacarendran Walia, Sumeet Sriram, Sharath Edgar, James H. Ramanathan, Shriram Alù, Andrea Abate, Yohannes Department of Physics and Astronomy University of Georgia AthensGA30602 United States Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical and Computer Engineering National University of Singapore Kent Ridge Singapore117583 Singapore School of Materials Engineering Purdue University West LafayetteIN47907 United States Tim Taylor Department of Chemical Engineering Kansas State University ManhattanKN 66506 United States School of Physics University of Melbourne ParkvilleVIC3010 Australia School of Engineering RMIT University MelbourneVIC Australia Functional Materials and Microsystems Research Group Micro Nano Research Facility RMIT University MelbourneVIC Australia ARC Centre of Excellence for Transformative Meta-Optical Systems RMIT University MelbourneVIC Australia Physics Program Graduate Center City University of New York New YorkNY10016 United States

Polaritons enable subwavelength confinement and highly anisotropic flows of light over a wide spectral range, holding the promise for applications in modern nanophotonic and optoelectronic devices. However, to fully realize their practical application potential, facile methods enabling nanoscale active control of polaritons are needed. Here, we introduce a hybrid polaritonic-oxide heterostructure platform consisting of van der Waals crystals, such as hexagonal boron nitride (hBN) or alpha-phase molybdenum trioxide (α-MoO3), transferred on nanoscale oxygen vacancy patterns on the surface of prototypical correlated perovskite oxide SmNiO3 (SNO). Using a combination of scanning probe microscopy and infrared nanoimaging techniques, we demonstrate nanoscale real-time reconfigurability of complex hyperbolic phonon polaritons patterned at the nanoscale with unmatched resolution. Hydrogenation and temperature modulation allow spatially localized conductivity modulation of SNO nanoscale patterns, enabling robust real-time modulation and nanoscale reconfiguration of hyperbolic polaritons. Our work paves the way towards nanoscale programmable metasurface engineering as a new paradigm for reconfigurable nanophotonic applications facilitated by a hybrid material platform exploiting extreme light-matter interactions in polaritonic systems. © 2021, CC BY.

关键词： Polariton

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Observation of anti-parity-time-symmetry, phase transitions and exceptional points in an optical fibre

arXiv

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arXiv 2020年

作者： Bergman, Arik Duggan, Robert Sharma, Kavita Tur, Moshe Zadok, Avi Alù, Andrea Faculty of Engineering Institute for Nano-Technology and Advanced Materials Bar-Ilan University Ramat-Gan5290002 Israel Photonics Initiative Advanced Science Research Center City University of New York New YorkNY10031 United States Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States School of Electrical Engineering Tel-Aviv University Tel-Aviv6997801 Israel Physics Program Graduate Center City University of New York New YorkNY10026 United States

The exotic physics emerging in non-Hermitian systems with balanced distributions of gain and loss has drawn a great deal of attention in recent years. These systems exhibit phase transitions and exceptional point singularities in their spectra, at which eigen-values and eigen-modes coalesce and the overall dimensionality is reduced. Among several peculiar phenomena observed at exceptional points, an especially intriguing property, with relevant practical potential, consists in the inherently enhanced sensitivity to small-scale perturbations. So far, however, these principles have been implemented at the expenses of precise fabrication and tuning requirements, involving tailored nano-structured devices with controlled distributions of optical gain and loss. In this work, anti-parity-time symmetric phase transitions and exceptional point singularities are demonstrated in a single strand of standard single-mode telecommunication fibre, using a setup consisting of entirely of off-the-shelf components. Two propagating signals are amplified and coupled through stimulated Brillouin scattering, which makes the process non-Hermitian and enables exquisite control over gain and loss. Singular response to small variations around the exceptional point and topological features arising around this singularity are experimentally demonstrated with large precision, enabling robustly enhanced spectral response to small-scale changes in the Brillouin frequency shift. Our findings open exciting opportunities for the exploration of non-Hermitian phenomena over a table-top setup, with straightforward extensions to higher-order Hamiltonians and applications in quantum optics, nanophotonics and sensing. Copyright © 2020, The Authors. All rights reserved.

关键词： Optical fibers

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Fast, accurate, and versatile data analysis platform for the quantification of molecular spatiotemporal signals

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Cell 2025年第10期188卷 2794-2809.e21页

作者： Mi, Xuelong Chen, Alex Bo-Yuan Duarte, Daniela Carey, Erin Taylor, Charlotte R. Braaker, Philipp N. Bright, Mark Almeida, Rafael G. Lim, Jing-Xuan Ruetten, Virginia M.S. Wang, Yizhi Wang, Mengfan Zhang, Weizhan Zheng, Wei Reitman, Michael E. Huang, Yongkang Wang, Xiaoyu Li, Lei Deng, HanFei Shi, Song-Hai Poskanzer, Kira E. Lyons, David A. Nimmerjahn, Axel Ahrens, Misha B. Yu, Guoqiang Bradley Department of Electrical and Computer Engineering Virginia Polytechnic Institute and State University Arlington 22203 VA United States Janelia Research Campus Howard Hughes Medical Institute Ashburn 20147 VA United States Department of Molecular and Cellular Biology Harvard University Cambridge 02138 MA United States Graduate Program in Neuroscience Harvard Medical School Boston 02115 MA United States Waitt Advanced Biophotonics Center The Salk Institute for Biological Studies La Jolla 92037 CA United States Department of Biochemistry & Biophysics University of California San Francisco San Francisco CA United States Neuroscience Graduate Program University of California San Francisco San Francisco CA United States Centre for Discovery Brain Sciences University of Edinburgh Edinburgh BioQuarter Edinburgh EH16 4SB United Kingdom Gatsby Computational Neuroscience Unit UCL London W1T 4JG United Kingdom Kavli Institute for Fundamental Neuroscience San Francisco CA United States Department of Automation Tsinghua University Beijing 100084 China IDG/McGovern Institute for Brain Research Tsinghua University Beijing 100084 China New Cornerstone Science Laboratory Tsinghua-Peking Center for Life Sciences Beijing Frontier Research Center for Biological Structure School of Life Sciences Tsinghua University Beijing 100084 China State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain Science Fudan University Shanghai 200032 China Beijing National Research Center for Information Science and Technology Beijing 100084 China

Optical recording of intricate molecular dynamics is becoming an indispensable technique for biological studies, accelerated by the development of new or improved biosensors and microscopy technology. This creates major computational challenges to extract and quantify biologically meaningful spatiotemporal patterns embedded within complex and rich data sources, many of which cannot be captured with existing methods. Here, we introduce activity quantification and analysis (AQuA2), a fast, accurate, and versatile data analysis platform built upon advanced machine-learning techniques. It decomposes complex live-imaging-based datasets into elementary signaling events, allowing accurate and unbiased quantification of molecular activities and identification of consensus functional units. We demonstrate applications across a wide range of biosensors, cell types, organs, animal models, microscopy techniques, and imaging approaches. As exemplar findings, we show how AQuA2 identified drug-dependent interactions between neurons and astroglia, as well as distinct sensorimotor signal propagation patterns in the mouse spinal cord. © 2025 The Author(s)

关键词： AQuA2 astrocytes cell interaction analysis functional units glial cells image analysis machine learning molecular spatiotemporal signals neurons time-lapse imaging

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A Control Strategy with Seamless Mode Transition for a Low-voltage Distributed Generation System Without an Energy Storage System 3

A Control Strategy with Seamless Mode Transition for a Low-v...

引用

3rd Workshop on Communication Networks and Power Systems, WCNPS 2018

作者： Ribeiro Damasceno, Yuri Iohanssen De Araújo Ribeiro, Ricardo Lúcio De Oliveira Alves Rocha, Thiago De Cavalcante Paiva, Sâmara Electrical and Computer Engineering Graduate Program - UFRN Natal Brazil Electrical Engineering Department Federal University of Rio Grande Do Norte - UFRN Natal Brazil Electrical Engineering Department Federal Rural University of the Semi-arid Region - UFERSA Caraúbas Brazil

ISBN: (纸本)9781728106700

The world energy demand is expected to rise in the coming decades. Renewable Energy Source Distributed Generation (RES-DG) is being used to meet this increased demand. RES-DG systems can serve local loads on an isolated system (autonomous operation) or connected to the power grid (grid-connected operation). Ideally, RES-DG systems should have the ability to transition smoothly between modes so that a continuous supply of power is achieved regardless of the grid state. This paper proposes a communication-less control strategy for a low-voltage RES-DG system capable of operating in autonomous as well in grid-connected mode and of achieving a smooth transfer between modes. An energy storage system is not required for operation in autonomous mode since the energy balance is maintained by acting in the power generated by the RES. The proposed control strategy is divided in three parts: (a) the VSI control, which constitutes the inner control loops of the Voltage Source Inverter (VSI) (current, voltage and power control loops), (b) mode-related control loops (DC link, voltage at the PCC and DG system angular frequency control loops) and (c) the synchronization and islanding detection methods. The control strategy is validated through simulation of a three-phase RES-DG system. The proposed strategy presents a smooth transition between modes, with little to no perturbation on the PCC voltage, and a fast synchronization process from autonomous to grid-connected mode. In addition, it also presents a fast DC link voltage control response time that is capable of maintaining the transitory small, even for large power imbalances during mode transition. © 2018 IEEE.

关键词： Distributed power generation

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Development of An POF-based Navigation System for People with Mild Cognitive Impairment Based on Wandering Detection

Development of An POF-based Navigation System for People wit...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Tsung-Yu Liu Tan-Hsu Tan Yung-Fa Huang Han-Lin Lin Shang-Chih Ma Ming-Yih Lee Shing-Hong Liu Department of Multimedia and Game Development Science Lunghwa University of Science and Technology Department of Electrical Engineering National Taipei University of Technology Department of Information and Communication Engineering Chaoyang University of Technology Graduate Institute of Biomedical Engineering Chang Gung University Department of Computer Science and Information Engineering Chaoyang University of Technology

This study develops a point of familiarity (POF)-based navigation system for people with mild cognitive impairment (PMCI) based on wandering detection. The proposed system has four main functionalities: optimal path planning, POF-based navigation, wandering detection, and remote route tracking. An improved A * algorithm which introduced the θ_WD approach is employed to plan an optimal path for the PMCI. As any wandering behavior is detected, the PMCI who holds a mobile phone will receive the pof data sent by the remote monitoring system for guiding to the point of familiarity (POF) to wait for rescue. The travelling status of the PMCI will be recorded by the remote route tracking unit. Experiment results show that the proposed system achieves the accuracy of 91.7% for wandering detection in the normal GPS environments. Furthermore, the POF-based navigation saves about 19% of the traveling time as compared to the MAP-based navigation approach. Therefore, the system has great potential in helping the PMCI to go home safely.

关键词： Global Positioning System Optical fibers Trajectory Senior citizens Lapping Servers

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Nanoscale probing of image-potential states and electron transfer doping in borophene polymorphs

arXiv

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arXiv 2020年

作者： Liu, Xiaolong Wang, Luqing Yakobson, Boris I. Hersam, Mark C. Applied Physics Graduate Program Northwestern University EvanstonIL60208 United States Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States Department of Chemistry Rice University HoustonTX77005 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States

Using field-emission resonance spectroscopy with an ultrahigh vacuum scanning tunneling microscope, we reveal Stark-shifted image-potential states of the v1/6 and v1/5 borophene polymorphs on Ag(111) with long lifetimes, suggesting high borophene lattice and interface quality. These image-potential states allow the local work function and interfacial charge transfer of borophene to be probed at the nanoscale and test the widely employed self-doping model of borophene. Supported by apparent barrier height measurements and density functional theory calculations, electron transfer doping occurs for both borophene phases from the Ag(111) substrate. In contradiction with the self-doping model, a higher electron transfer doping level occurs for denser v1/6 borophene compared to v1/5 borophene, thus revealing the importance of substrate effects on borophene electron transfer. Copyright © 2020, The Authors. All rights reserved.

关键词： Electron transitions

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Application of Message Security Application Using Vigenere Cipher Algorithm Utilizing One Time Pad (OTP) Algorithm as a Key Generator 1

Application of Message Security Application Using Vigenere C...

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1st Workshop on Environmental Science, Society, and Technology, WESTECH 2018

作者： Pardede, A.M.H. Br Sitepu, Lorena Perbina Zarlis, Muhammad Tulus Iskandar, Akbar Sriadhi, S. Manurung, Rosida Tiurma Siregar, Nurintan Asyiah Sari, Ayu Esteka Yunawati, Sri Mursyidah, M. Mursalin, M. Kurniasih, Nuning Kurniawan, Citra Winarno, Edy STMIK Kaputama Sumatera Utara Binjai Indonesia Department of Computer Science Universitas Sumatera Utara Medan Indonesia Department of Mathematics Universitas Sumatera Utara Medan Indonesia Department of Electrical Engineering Universitas Negeri Medan Indonesia Graduate Program in Scientific Psychology Universitas Kristen Maranatha Indonesia Department of Management STIE Labuhanbatu Sumatera Utara Indonesia Department of Management STIE Sakti Alam Kerinci Jambi Indonesia Program Study of Accounting Pasir Pengaraian University Riau Indonesia Departement of Information Technology and Computer Politeknik Negeri Lhokseumawe Aceh Indonesia Department of Mathematics Education Universitas Malikussaleh Aceh Indonesia Faculty of Communication Sciences Library and Information Science Program Universitas Padjadjaran Bandung Indonesia Department of Electrical Engineering Sekolah Tinggi Teknik Malang Indonesia Faculty of Information Technology Universitas Stikubank Semarang Indonesia

Cryptography is the science and art of maintaining the security of messages when messages are sent from one place to another. One of the ways securing the form of text message information is by the encryption process using the Vigenere Cipher algorithm and utilizing the One Time Pad (OTP) algorithm as a key generator, where the message will be random when it is opened. The message encryption process used the vigenere cipher algorithm while OTP is used to secure the key with the same formula. After this research has been done, an application was designed to secure text messages by converting the text message into a random message so that the message was unreadable due to a secret message that could not be known by others. The results achieved can secure an encrypted message that cannot be reopened and if those messages were reopened, they must be decrypted. © Published under licence by IOP Publishing Ltd.

关键词： Cryptography

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Design approach for additive manufacturing in spare part supply chains

arXiv

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arXiv 2020年

作者： de Brito, Filipe Marinho da Cruz Júnior, Gélson Frazzon, Enzo Morosini Basto, João Pedro Tavares Vieira Alcalá, Symone Gomes Soares School of Electrical Mechanical and Computer Engineering Federal University of Goiás GoiâniaGoiás74605-010 Brazil INESC P&D Brasil São Paulo11055-300 Brazil Graduate Program in Production Engineering Department of Production Engineering and Systems Federal University of Santa Catarina Florianópolis88040-900 Brazil Department of Industrial Engineering and Management Faculty of Engineering University of Porto Porto4200-465 Portugal INESC TEC - Technology Faculty of Engineering University of Porto Porto4200-465 Portugal Production Engineering Faculty of Sciences and Technology Federal University of Goiás Aparecida de Goiânia Goiás74968-755 Brazil

In the current industrial revolution, additive manufacturing (AM) embodies a promising technology that can enhance the effectiveness, adaptability, and competitiveness of supply chains (SCs). Moreover, it facilitates the development of distributed SCs, thereby enhancing product availability, inventory levels, and lead time. However, the wide adoption of AM in industrial SCs creates various challenges, leading to new difficulties for SC design. In this context, this paper proposes a new design approach to AM SCs using optimization methods. More specifically, the proposed approach, comprising the pmedian and mixed-integer linear programming models, considers the decision of deploying productive resources (3D printers) in specific locations of generic spare part SCs. The approach was evaluated in a real-world use case of an elevator maintenance service provider. The obtained results demonstrated the promising capabilities of the proposed design approach in managing the challenges arising from the forthcoming widespread use of 3D printers in manufacturing SCs. © 2020, CC-BY-NC-ND.

关键词： 3D printers

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Spectral evidence for unidirectional charge density wave in detwinned BaNi2As2

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Physical Review B 2023年第8期108卷 L081104-L081104页

作者： Yucheng Guo Mason Klemm Ji Seop Oh Yaofeng Xie Bing-Hua Lei Luca Moreschini Cheng Chen Ziqin Yue Sergey Gorovikov Tor Pedersen Matteo Michiardi Sergey Zhdanovich Andrea Damascelli Jonathan Denlinger Makoto Hashimoto Donghui Lu Chris Jozwiak Aaron Bostwick Eli Rotenberg Sung-Kwan Mo Rob G. Moore Junichiro Kono Robert J. Birgeneau David J. Singh Pengcheng Dai Ming Yi Department of Physics and Astronomy Rice University Houston Texas 77005 USA Advanced Light Source Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Physics University of California Berkeley California 94720 USA Department of Physics and Astronomy University of Missouri Columbia Missouri 65211 USA Materials Science Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA Department of Physics University of Oxford Oxford OX1 3PU United Kingdom Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston Texas 77005 USA Canadian Light Source Inc. 44 Innovation Boulevard Saskatoon SK S7N 2V3 Canada Department of Physics and Astronomy University of British Columbia Vancouver British Columbia V6T 1Z1 Canada Quantum Matter Institute University of British Columbia Vancouver British Columbia V6T 1Z4 Canada Max Planck Institute for Chemical Physics of Solids Nöthnitzer Straße 40 01187 Dresden Germany Stanford Synchrotron Radiation Lightsource SLAC National Accelerator Laboratory Menlo Park California 94025 USA Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Electrical and Computer Engineering Rice University Houston Texas 77005 USA Smalley-Curl Institute Rice University Houston Texas 77005 USA Department of Materials Science and NanoEngineering Rice University Houston Texas 77005 USA Department of Chemistry University of Missouri Columbia Missouri 65211 USA

In the iron-based superconductors, unconventional superconductivity emerges in proximity to intertwined electronic orders consisting of an electronic nematic order and a spin density wave (SDW). Recently, BaNi2As2, like its well-known iron-based analog BaFe2As2, has been discovered to host a symmetry-breaking structural transition but coupled to a unidirectional charge density wave (CDW) instead of SDW, providing a novel platform to study intertwined orders. Here, through a systematic angle-resolved photoemission spectroscopy study combined with a detwinning B1g uniaxial strain, we identify distinct spectral evidence of band evolution due to the structural transition as well as CDW-induced band folding. In contrast to the nematicity and spin density wave in BaFe2As2, the structural and CDW order parameters in BaNi2As2 are observed to be strongly coupled and do not separate in the presence of uniaxial strain. Furthermore, no nematic band splitting is resolved above the structural transition. Our measurements point to a likely lattice origin of the CDW order in BaNi2As2.

关键词： Charge density waves Nematic phase transition Iron-based superconductors Angle-resolved photoemission spectroscopy

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