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Internal nanostructure diagnosis with hyperbolic phonon polaritons in hexagonal boron nitride

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arXiv 2018年

作者： Dai, Siyuan Tymchenko, Mykhailo Xu, Zai-Quan Tran, Toan T. Yang, Yafang Ma, Qiong Watanabe, Kenji Taniguchi, Takashi Jarillo-Herrero, Pablo Aharonovich, Igor Basov, Dimitri N. Tao, Tiger H. Alù, Andrea Department of Electrical & Computer Engineering University of Texas AustinTX78712 United States Institute of Biomedical Materials and Devices Faculty of Science University of Technology Sydney UltimoNSW2007 Australia Department of Physics Massachusetts Institute of Technology CambridgeMA02215 United States National Institute for Materials Science Namiki 1-1 Tsukuba Ibaraki305-0044 Japan Department of Physics Columbia University New YorkNY10027 United States Department of Mechanical Engineering University of Texas AustinTX78712 United States Photonics Initiative Advanced Science Research Center City University of New York New York10031 United States Physics Program Graduate Center City University of New York New York10016 United States Department of Electrical Engineering City College of the City University of New York New York10031 United States

Imaging materials and inner structures with resolution below the diffraction limit has become of fundamental importance in recent years for a wide variety of applications. In this work, we report sub-diffractive internal structure diagnosis of hexagonal boron nitride by exciting and imaging hyperbolic phonon polaritons. Based on their unique propagation properties, we are able to accurately locate defects in the crystal interior with nanometer resolution. The precise location, size and geometry of the concealed defects is reconstructed by analyzing the polariton wavelength, reflection coefficient and their dispersion. We have also studied the evolution of polariton reflection, transmission and scattering as a function of defect size and photon frequency. The nondestructive high-precision polaritonic structure diagnosis technique introduced here can be also applied to other hyperbolic or waveguide systems, and may be deployed in the next-generation bio-medical imaging, sensing and fine structure analysis. Copyright © 2018, The Authors. All rights reserved.

关键词： Van der Waals forces

Set-up of active magnetic bearings for control of flexible shaft

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AIP Conference Proceedings 2018年第1期2029卷

作者： Adam Piłat Bartosz Sikora Jan Klocek Jan Cieślik 1AGH University of Science and Technology Faculty of Electrical Engineering Automatics Computer Science and Biomedical Engineering Department of Automatic Control and Robotics Mickiewicza 30 30-059 Krakow Poland 2Optister Jalowcowa 50 31-329 Krakow Poland 3AGH University of Science and Technology Faculty of Mechanical Engineering and Robotics Department of Manufacturing Systems Mickiewicza 30 30-059 Krakow Poland

This paper presents the new laboratory test rig of the vertical axis flexible shaft supported by two active magnetic bearings. Behind the motivation of establishing this setup is the control of vibration modes of the flexible rotor - shaft assembly, while the rotational speed varies and the unbalanced mass on the whirling disc is introduced to the system. The proposed model is aimed to simulate real operation conditions of the rotating machinery with an applied external load, with a variable structure caused by a change of material properties of the rotor - shaft assembly, or due to a fault of some elements coupled with the rotor.

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On the Potential Galactic Origin of the Ultra-High-Energy Event KM3-230213A

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arXiv 2025年

作者： Adriani, O. Aiello, S. Albert, A. Alhebsi, A.R. Alshamsi, M. Garre, S. Alves Ambrosone, A. Ameli, F. Andre, M. Aphecetche, L. Ardid, M. Ardid, S. Aublin, J. Badaracco, F. Bailly-Salins, L. Bardačová, Z. Baret, B. Bariego-Quintana, A. Becherini, Y. Bendahman, M. Gualandi, F. Benfenati Benhassi, M. Bennani, M. Benoit, D.M. Berbee, E. Berti, E. Bertin, V. Betti, P. Biagi, S. Boettcher, M. Bonanno, D. Bottai, S. Bouasla, A.B. Boumaaza, J. Bouta, M. Bouwhuis, M. Bozza, C. Bozza, R.M. Brânzaş, H. Bretaudeau, F. Breuhaus, M. Bruijn, R. Brunner, J. Bruno, R. Buis, E. Buompane, R. Busto, J. Caiffi, B. Calvo, D. Capone, A. Carenini, F. Carretero, V. Cartraud, T. Castaldi, P. Cecchini, V. Celli, S. Cerisy, L. Chabab, M. Chen, A. Cherubini, S. Chiarusi, T. Circella, M. Clark, R. Cocimano, R. Coelho, J.A.B. Coleiro, A. Condorelli, A. Coniglione, R. Coyle, P. Creusot, A. Cuttone, G. Dallier, R. De Benedittis, A. De Wasseige, G. Decoene, V. Deguire, P. Del Rosso, I. Di Mauro, L.S. Di Palma, I. Díaz, A.F. Diego-Tortosa, D. Distefano, C. Domi, A. Donzaud, C. Dornic, D. Drakopoulou, E. Drouhin, D. Ducoin, J.-G. Duverne, P. Dvornický, R. Eberl, T. Eckerová, E. Eddymaoui, A. van Eeden, T. Eff, M. van Eijk, D. Bojaddaini, I.El. Hedri, S.El. Mentawi, S.El. Ellajosyula, V. Enzenhöfer, A. Ferrara, G. Filipović, M.D. Filippini, F. Franciotti, D. Fusco, L.A. Gal, T. Méndez, J. García Soto, A. Garcia Oliver, C. Gatius Geißelbrecht, N. Genton, E. Ghaddari, H. Gialanella, L. Gibson, B.K. Giorgio, E. Goos, I. Goswami, P. Gozzini, S.R. Gracia, R. Guidi, C. Guillon, B. Gutiérrez, M. Haack, C. van Haren, H. Heijboer, A. Hennig, L. Hernández-Rey, J.J. Idrissi, A. Ibnsalih, W. Idrissi Illuminati, G. Janik, O. Joly, D. de Jong, M. de Jong, P. Jung, B.J. Kalaczyński, P. Keegans, J. Kikvadze, V. Kistauri, G. Kopper, C. Kouchner, A. Kovalev, Y.Y. Krupa, L. Kueviakoe, V. Kulikovskiy, V. Kvatadze, R. Labalme, M. Lahmann, R. INFN Sezione di Firenze via Sansone 1 Sesto Fiorentino50019 Italy Università di Firenze Dipartimento di Fisica e Astronomia via Sansone 1 Sesto Fiorentino50019 Italy Via Santa Sofia 64 Catania95123 Italy Université de Strasbourg CNRS IPHC UMR 7178 StrasbourgF-67000 France Université de Haute Alsace rue des Frères Lumière Mulhouse68093Cedex France Khalifa University of Science and Technology Department of Physics PO Box 127788 Abu Dhabi United Arab Emirates Aix Marseille Univ CNRS IN2P3 CPPM Marseille France c/Catedrático José Beltrán 2 Valencia Paterna46980 Spain Università di Napoli "Federico II" Dip. Scienze Fisiche "E. Pancini" Complesso Universitario di Monte S. Angelo Via Cintia ed. G Napoli80126 Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo Via Cintia ed. G Napoli80126 Italy INFN Sezione di Roma Piazzale Aldo Moro 2 Roma00185 Italy Universitat Politècnica de Catalunya Laboratori d’Aplicacions Bioacústiques Centre Tecnològic de Vilanova i la Geltrú Avda. Rambla Exposició s/n Vilanova i la Geltrú08800 Spain Subatech IMT Atlantique IN2P3 CNRS Nantes Université 4 rue Alfred Kastler - La Chantrerie BP Nantes20722 44307 France Universitat Politècnica de València Instituto de Investigación para la Gestión Integrada de las Zonas Costeras C/ Paranimf 1 Gandia46730 Spain Université Paris Cité CNRS Astroparticule et Cosmologie ParisF-75013 France INFN Sezione di Genova Via Dodecaneso 33 Genova16146 Italy Università di Genova Via Dodecaneso 33 Genova16146 Italy LPC CAEN Normandie Univ ENSICAEN UNICAEN CNRS IN2P3 6 boulevard Maréchal Juin Caen14050 France Comenius University in Bratislava Department of Nuclear Physics and Biophysics Mlynska dolina F1 Bratislava842 48 Slovakia Czech Technical University in Prague Institute of Experimental and Applied Physics Husova 240/5 Prague110 00 Czech Republic Università di Bologna Dipartimento di Fisica e Astronomia v.le C. Berti-Pichat 6/2

The KM3NeT observatory detected the most energetic neutrino candidate ever observed, with an energy between 72 PeV and 2.6 EeV at the 90 % confidence level. The observed neutrino is likely of cosmic origin. In this article, it is investigated if the neutrino could have been produced within the Milky Way. Considering the low fluxes of the Galactic diffuse emission at these energies, the lack of a nearby potential Galactic particle accelerator in the direction of the event and the difficulty to accelerate particles to such high energies in Galactic systems, we conclude that if the event is indeed cosmic, it is most likely of extragalactic origin. Copyright © 2025, The Authors. All rights reserved.

关键词： Neutrons

Medical image denoising using sparse representations

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Medical image denoising using sparse representations

International Conference on Awareness science and Technology (iCAST)

作者： Fatma S. Abousaleh Neng-Hao Yu Kai-Lung Hua Wen-Huang Cheng Social Networks and Human Centered Computing Program Institute of Information Science Research Center for Information Technology Innovation Academia Sinica Taipei Taiwan Department of Computer Science National Chengchi University Taipei Taiwan Department of Computer Science and Information Engineering Taiwan University of Science and Technology Taipei Taiwan

Image noise reduction, or denoising, became an attractive research domain in the recent years. There are several published approaches in the image denoising field and each one has its presumptions, advantages, and limitations. In this paper, we address the problem of eliminating or even decreasing the noise from medical images. Some schemes for image noise reduction are proposed. The schemes include DCT_OMP, DCT_BOMP, Log Gabor_BOMP, DCT_OCMP and Wavelet_OMP. In these schemes, the image content is represented as a sparse linear combination of a set of atoms that can be obtained from some trained dictionaries. In literature, several algorithms are proposed to build up these kinds of dictionaries. In our study, the K-SVD algorithm is utilized to obtain a dictionary that can effectively describe the image. Also, some greedy algorithms are used to perform the sparse-coding of the signal. The proposed schemes have been tested on two different medical images with different levels of an additive noise. The Log Gabor_BOMP scheme showed a significant outperformance, in both the de-noising results and computational time, on all the other schemes.

关键词： Matching pursuit algorithms Dictionaries Approximation algorithms Image denoising Noise reduction Discrete cosine transforms Algorithm design and analysis

Wildlife-microbiome interactions and disease: exploring opportunities for disease mitigation across ecological scales

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Drug Discovery Today: Disease Models 2018年 28卷 105-115页

作者： Williams, Candace L. Caraballo-Rodríguez, Andrés Mauricio Allaband, Celeste Zarrinpar, Amir Knight, Rob Gauglitz, Julia M. Institute for Conservation Research San Diego Zoo Global United States Collaborative Mass Spectrometry Innovation Center Skaggs School of Pharmacy and Pharmaceutical Sciences University of California La Jolla San Diego 92307 CA United States Biomedical Sciences Graduate Program University of California La Jolla San Diego 92307 CA United States Department of Medicine University of California La Jolla San Diego 92307 CA United States Veterans Affairs San Diego Healthcare System San Diego California University of California La Jolla San Diego 92307 CA United States Department of Pediatrics University of California La Jolla San Diego 92037 CA United States Department of Bioengineering University of California La Jolla San Diego 92093 CA United States Department of Computer Science and Engineering University of California La Jolla San Diego 92093 CA United States Center for Microbiome Innovation University of California La Jolla San Diego 92307 CA United States

Captive wildlife are a unique set of animals, whose diverse host–microbe symbioses are underexplored. Compared to their wild counterparts they are particularly susceptible to a variety of diseases, many of which have explicit or purported links to the microbiome. In this perspective, we will examine how the microbiome influences gastrointestinal disorders, metabolic dysregulation, reproduction, and disease susceptibility in captive wildlife. Investigation of wildlife, and specifically captive wildlife, affords a unique opportunity to gain understanding of the broad diversity of the associated microbiota and learn from nature's molecular and microbial responses to disease. Studies like these could lead to the discovery of new interventions, ranging from dietary changes to the use of microbes or their natural products as treatment. Intervention strategies can lead to the discovery of medically relevant small molecules and the development of a novel platform for N-of-1 targeted medical investigations. © 2019 Elsevier Ltd

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Single shot ultrafast all optical magnetization switching of ferromagnetic Co/Pt multilayers

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Single shot ultrafast all optical magnetization switching of...

Berkeley Symposium on Energy Efficient Electronic Systems (E3S)

作者： Jon Gorchon Charles-Henri Lambert Yang Yang Akshay Pattabi Richard B. Wilson Sayeef Salahuddin Jeffrey Bokor Lawrence Berkeley National Laboratory Berkeley CA USA Department of Electrical Engineering and Computer Sciences University of California Berkeley CA USA Department of Materials Science and Engineering University of California Berkeley CA USA Department of Mechanical Engineering and Materials Science and Engineering Program University of California Riverside CA USA

ISBN: (纸本)9781538632918

The ability to control magnetism in sub-picosecond timescales using laser pulses has potential applications in fast magnetic devices. It has been demonstrated that a single femto-second laser pulse can reverse the magnetization of a film within a few picoseconds [1], a phenomenon called as all-optical switching (AOS). However, this phenomenon thus far has been observed only in ferrimagnetic GdFeCo films. On the other hand, ferromagnetic films, which are of greater interest than ferrimagnets in many technological applications, need multiple laser pulses for magnetization reversal [2], making the overall effect slow and energy inefficient. Fast, single-shot switching of a ferromagnet can open up new avenues for spintronic devices that operate at unprecedented picosecond timescales, thereby making them viable non-volatile replacements for silicon based RAMs and logic devices.

关键词： Optical switches Magnetization Ultrafast optics Magnetic separation Optical films Optical pulses

A novel approach for ellipsoidal outer-approximation of the intersection region of ellipses in the plane

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arXiv 2017年

作者： Yousefi, Siamak Chang, Xiao-Wen Wymeersch, Henk Champagne, Benoit Toussaint, Godfried Department of Electrical and Computer Engineering McGill University MontrealQC Canada School of Computer Science McGill University MontrealQC Canada Department of Signals and Systems Chalmers University of Technology Gothenburg Sweden Computer Science Program New York University Abu Dhabi United Arab Emirates

In this paper, a novel technique for tight outer-approximation of the intersection region of a finite number of ellipses in 2-dimensional (2D) space is proposed. First, the vertices of a tight polygon that contains the convex intersection of the ellipses are found in an efficient manner. To do so, the intersection points of the ellipses that fall on the boundary of the intersection region are determined, and a set of points is generated on the elliptic arcs connecting every two neighbouring intersection points. By finding the tangent lines to the ellipses at the extended set of points, a set of half-planes is obtained, whose intersection forms a polygon. To find the polygon more efficiently, the points are given an order and the intersection of the half-planes corresponding to every two neighbouring points is calculated. If the polygon is convex and bounded, these calculated points together with the initially obtained intersection points will form its vertices. If the polygon is non-convex or unbounded, we can detect this situation and then generate additional discrete points only on the elliptical arc segment causing the issue, and restart the algorithm to obtain a bounded and convex polygon. Finally, the smallest area ellipse that contains the vertices of the polygon is obtained by solving a convex optimization problem. Through numerical experiments, it is illustrated that the proposed technique returns a tighter outer-approximation of the intersection of multiple ellipses, compared to conventional techniques, with only slightly higher computational cost. Copyright © 2017, The Authors. All rights reserved.

关键词： Convex optimization

Author Correction: Effect of de novo transcriptome assembly on transcript quantification

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Scientific reports 2019年第1期9卷 18041页

作者： Ping-Han Hsieh Yen-Jen Oyang Chien-Yu Chen Graduate Institute of Biomedical Electronics and Bioinformatics National Taiwan University Taipei 10617 Taiwan. Department of Computer Science and Information Engineering National Taiwan University Taipei 10617 Taiwan. Department of Bio-Industrial Mechatronics Engineering National Taiwan University Taipei 10617 Taiwan. chienyuchen@ntu.edu.tw. Genome and Systems Biology Program National Taiwan University and Academia sinica Taipei 10617 Taiwan. chienyuchen@ntu.edu.tw.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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Streaming k-means clustering with fast queries

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arXiv 2017年

作者： Zhang, Yu Tangwongsan, Kanat Tirthapura, Srikanta Department of Electrical and Computer Engineering Iowa State University AmesIA50011 United States Compute Science Program Mahidol University International College Thailand Department of Electrical and Computer Engineering Iowa State University AmesIA50011 United States

We present methods for k-means clustering on a stream with a focus on providing fast responses to clustering queries. Compared to the current state-of-the-art, our methods provide substantial improvement in the query time for cluster centers while retaining the desirable properties of provably small approximation error and low space usage. Our algorithms rely on a novel idea of "coreset caching" that systematically reuses coresets (summaries of data) computed for recent queries in answering the current clustering query. We present both theoretical analysis and detailed experiments demonstrating their correctness and efficiency. Copyright © 2017, The Authors. All rights reserved.

关键词： Machine learning