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Spin absorption by in situ deposited nanoscale magnets on graphene spin valves

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arXiv 2018年

作者： Amamou, Walid Stecklein, Gordon Koester, Steven J. Crowell, Paul A. Kawakami, Roland K. Program of Materials Science and Engineering University of California RiversideCA92521 United States School of Physics and Astronomy University of Minnesota MinneapolisMN55455 United States Department of Electrical and Computer Engineering University of Minnesota MinneapolisMN55455 United States Department of Physics Ohio State University ColumbusOH43210 United States

An in situ measurement of spin transport in a graphene nonlocal spin valve is used to quantify the spin current absorbed by a small (250 nm × 750 nm) metallic island. The experiment allows for successive depositions of either Fe or Cu without breaking vacuum, so that the thickness of the island is the only parameter that is varied. Furthermore, by measuring the effect of the island using separate contacts for injection and detection, we isolate the effect of spin absorption from any change in the spin injection and detection mechanisms. As inferred from the thickness dependence, the effective spin current je= 2e/h jsabsorbed by Fe is as large as 108A/m2. The maximum value of jeis limited by the resistance-area product of the graphene/Fe interface, which is as small as 3 Ωμm2. The spin current absorbed by the same thickness of Cu is smaller than for Fe, as expected given the longer spin diffusion length and larger spin resistance of Cu compared to Fe. These results allow for a quantitative assessment of the prospects for achieving spin transfer torque switching of a nanomagnet using a graphene-based nonlocal spin valve. Copyright © 2018, The Authors. All rights reserved.

关键词： Graphene

Eavesdropper’s ability to attack a free-space quantum-key-distribution receiver in atmospheric turbulence

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arXiv 2019年

作者： Chaiwongkhot, Poompong Kuntz, Katanya B. Zhang, Yanbao Huang, Anqi Bourgoin, Jean-Philippe Sajeed, Shihan Lütkenhaus, Norbert Jennewein, Thomas Makarov, Vadim Institute for Quantum Computing University of Waterloo WaterlooONN2L 3G1 Canada Department of Physics and Astronomy University of Waterloo WaterlooONN2L 3G1 Canada NTT Basic Research Laboratories NTT Corporation AtsugiKanagawa Japan NTT Research Center for Theoretical Quantum Physics NTT Corporation AtsugiKanagawa Japan Institute for Quantum Information & State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Changsha410073 China Department of Electrical and Computer Engineering University of Waterloo WaterlooONN2L 3G1 Canada Aegis Quantum WaterlooON Canada Department of Electrical and Computer Engineering University of Toronto M5S 3G4 Canada Quantum Information Science Program Canadian Institute for Advanced Research TorontoONM5G 1Z8 Canada Russian Quantum Center Skolkovo Moscow143025 Russia Shanghai Branch National Laboratory for Physical Sciences at Microscale and CAS Center for Excellence in Quantum Information University of Science and Technology of China Shanghai201315 China NTI Center for Quantum Communications National University of Science and Technology MISiS Moscow119049 Russia

The ability of an eavesdropper (Eve) to perform an intercept-resend attack on a free-space quantum key distribution (QKD) receiver by precisely controlling the incidence angle of an attack laser has been previously demonstrated. However, such an attack could be ineffective in the presence of atmospheric turbulence due to beam wander and spatial mode aberrations induced by the air’s varying index of refraction. We experimentally investigate the impact turbulence has on Eve’s attack on a free-space polarization-encoding QKD receiver by emulating atmospheric turbulence with a spatial light modulator. Our results identify how well Eve would need to compensate for turbulence to perform a successful attack by either reducing her distance to the receiver, or using beam wavefront correction via adaptive optics. Furthermore, we use an entanglement-breaking scheme to find a theoretical limit on the turbulence strength that hinders Eve’s attack. Copyright © 2019, The Authors. All rights reserved.

关键词： Atmospheric turbulence

Single-photon embedded eigenstates in coupled cavity-atom systems

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arXiv 2018年

作者： Cotrufo, Michele Alù, Andrea Department of Electrical and Computer Engineering University of Texas at Austin AustinTX78712 United States Photonics Initiative Advanced Science Research Center City University of New York NY10031 United States Physics Program Graduate Center City University of New York NY10016 United States Department of Electrical Engineering City College of The City University of New York NY10031 United States

Confining light in open structures is a long-sought goal in nanophotonics and cavity quantum electrodynamics. Embedded eigenstates provide infinite lifetime despite the presence of available leakage channels, but in linear time-invariant systems they cannot be excited from the outside, due to reciprocity. Here, we investigate how atomic nonlinearities may support single-photon embedded eigenstates, which can be populated by a multi-photon excitation followed by internal relaxation. We calculate the system dynamics and show that photon trapping, as well as the reverse release process, can be achieved with arbitrarily high efficiencies. We also discuss the impact of loss, and a path towards the experimental verification of these concepts. Copyright © 2018, The Authors. All rights reserved.

关键词： Particle beams

Tissue tropisms of avian influenza A viruses affect their spillovers from wild bird to domestic swine

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Tissue tropisms of avian influenza A viruses affect their sp...

作者： Xiaojian Zhang Fred L.Cunningham Lei Li Katie Hanson-Dorr Alicia Olivier Liyuan Liu Brandon S.Schmit Minhui Guan Jacqueline M.Nolting Andrew S.Bowman Mia Kim Torchetti Thomas J.DeLiberto Xiu-Feng Wan Missouri University Center for Research on Influenza Systems Biology (CRISB) University of Missouri Bond Life Sciences Center University of Missouri Department of Molecular Microbiology and Immunology School of Medicine University of Missouri Department of Basic Sciences College of Veterinary Medicine Mississippi State University Mississippi Field Station National Wildlife Research Center Wildlife Services Animal and Plant Health Inspection Service U.S. Department of Agriculture Department of Population and Pathobiology College of Veterinary Medicine Mississippi State University National Wildlife Disease Program Wildlife Services Animal and Plant Health Inspection Service U.S. Department of Agriculture Department of Veterinary Preventive Medicine The Ohio State University National Veterinary Services Laboratories Veterinary Services U.S. Department of Agriculture Department of Electrical Engineering & Computer Science College of Engineering University of Missouri Department of Pathobiology College of Veterinary Medicine University of Missouri MU Informatics Institute University of Missouri

Having both avian-like receptors (?±2,3-linked sialic acid, SA2,3Gal) and human-like receptors (?±2,6-linked sialic acid, SA2,6Gal), swine are proposed as??úmixing vessel??ùfor generating influenza pandemic strains. Laboratory experiments suggested all HA subtypes of influenza A virus (IAV) can infect swine. However, only sporadic cases of avian

关键词： Tissue tropisms of avian influenza A viruses affect their spillovers from wild bird to domestic swine

Accurate color imaging of pathology slides using holography and absorbance spectrum estimation of histochemical stains

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arXiv 2018年

作者： Zhang, Yibo Liu, Tairan Huang, Yujia Teng, Da Bian, Yinxu Wu, Yichen Rivenson, Yair Feizi, Alborz Ozcan, Aydogan Electrical and Computer Engineering Department University of California Los AngelesCA90095 United States Bioengineering Department University of California Los AngelesCA90095 United States University of California Los AngelesCA90095 United States Computer Science Department University of California Los AngelesCA90095 United States Department of Biomedical Engineering Yale University New HavenCT06520 United States Department of Surgery David Geffen School of Medicine University of California Los AngelesCA90095 United States

Holographic microscopy presents challenges for color reproduction due to the usage of narrow-band illumination sources, which especially impacts the imaging of stained pathology slides for clinical diagnoses. Here, an accurate color holographic microscopy framework using absorbance spectrum estimation is presented. This method uses multispectral holographic images acquired and reconstructed at a small number (e.g., three to six) of wavelengths, estimates the absorbance spectrum of the sample, and projects it onto a color tristimulus. Using this method, the wavelength selection is optimized to holographically image 25 pathology slide samples with different tissue and stain combinations to significantly reduce color errors in the final reconstructed images. The results can be used as a practical guide for various imaging applications and, in particular, to correct color distortions in holographic imaging of pathology samples spanning different dyes and tissue *** Codes 78A10 Copyright © 2018, The Authors. All rights reserved.

关键词： Spectrum analysis

Crimp analysis of connective tissue using quantitative second-harmonic generation microscopy

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Crimp analysis of connective tissue using quantitative secon...

Frontiers in Optics, FiO 2017

作者： Lee, Woowon Rahman, Hafizur Kersh, Mariana E. Toussaint, Kimani C. University of Illinois at Urbana-Champaign Department of Mechanical Science and Engineering UrbanaIL United States University of Illinois at Urbana-Champaign PROBE Lab UrbanaIL United States University of Illinois at Urbana-Champaign Affiliate in the Departments of Electrical and Computer Engineering and Bioengineering UrbanaIL United States

We assess the capacity for second-harmonic generation (SHG) microscopy by quantitatively characterizing collagen fiber crimp pattern in the posterior cruciate ligament (PCL) and disclosing the 3D structure in PCL and ... 详细信息

ISBN: (纸本)9781943580330

关键词： Harmonic generation

Modeling faults in communication protocols based on an aspect-oriented method 15

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Modeling faults in communication protocols based on an aspec...

15th IEEE International Conference on Industrial Informatics, INDIN 2017

作者： Dos Santos Roque, Alexandre Steinmetz, Charles Freitas, Edison Pignaton Pereira, Carlos Eduardo Federal University of Rio Grande Do sul - UFRGS Graduate Program in Electrical Engineering PPGEE Porto Alegre RS Brazil Regional Integrated University of High Uruguay and Missions URI Engineering and Computer Science Department Santo Ângelo RS Brazil

ISBN: (纸本)9781538608371

Faults in industrial communication protocols represent an important problem for industrial systems as they may lead to severe losses. Observing the need for approaches to deal with this type of problem, this paper studies reliability aspects related to industrial communication protocols and the modeling of possible communication faults. The work proposes a requirements specification based on aspect-oriented concepts to map and model common faults in design phases of embedded systems. A model integrating fault modeling in communication protocols extending the Real-Time From Requirements to Design using Aspects (RT-FRIDA) framework is presented. A case study on vehicular networks was conducted considering the nonfunctional requirements specification of an Active Suspension System. Then, a sequence of fault requirements based in recent studies is modeled and presented to validate the proposed approach. The main contribution of this work is to enable the use of fault modeling in communication protocols and aspect-oriented modeling techniques to mitigate the fault impact in the timing behavior of critical tasks. This study indicates the use of observers' technique modeled to fault diagnosis, so that they can be aggregated into a real-time control system. © 2017 IEEE.

关键词： Embedded systems

Tissue engineering: Controlled Apoptosis of Stromal Cells to Engineer Human Microlivers (Adv. Funct. Mater. 48/2020)

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Advanced Functional Materials 2020年第48期30卷

作者： Amanda X. Chen Arnav Chhabra Hyun‐Ho Greco Song Heather E. Fleming Christopher S. Chen Sangeeta N. Bhatia Department of Biological Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA Koch Institute for Integrative Cancer Research Massachusetts Institute of Technology Cambridge MA 02139 USA Harvard–MIT Program in Health Sciences and Technology Institute for Medical Engineering and Science Massachusetts Institute of Technology Cambridge MA 02139 USA Biological Design Center Department of Biomedical Engineering Boston University Boston MA 02215 USA Wyss Institute for Biologically Inspired Engineering Boston MA 02115 USA Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge MA 02142 USA Department of Medicine Brigham and Women's Hospital and Harvard Medical School Boston MA 02115 USA Broad Institute of Massachusetts Institute of Technology and Harvard Cambridge MA 02139 USA Howard Hughes Medical Institute Chevy Chase MD 20815 USA

Doubly Penalized LASSO for Reconstruction of Biological Networks

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Doubly Penalized LASSO for Reconstruction of Biological Netw...

作者： Asadi, Behrang Maurya, Mano Ram Tartakovsky, Daniel M. Subramaniam, Shankar Departments of Bioengineering and Mechanical and Aerospace Engineering University of California San Diego Danaher Labs la Jolla Santa ClaraCA United States San Diego Supercomputer Center Department of Bioengineering University of California San Diego San DiegoCA United States Department of Mechanical Aerospace Engineering University of California San Diego San DiegoCA United States Department of Bioengineering Departments of Computer Science and Engineering Cellular and Molecular Medicine and the Graduate Program in Bioinformatics University of California San Diego San DiegoCA United States

Reconstruction of biological and biochemical networks is a crucial step in extracting knowledge and causal information from large biological data sets. This task is particularly challenging when dealing with time-series data from dynamic networks. We have developed a new method, called doubly penalized least absolute shrinkage and selection operator (DPLASSO), for the reconstruction of dynamic biological networks. Our method consists of two components: statistical significance testing of model coefficients and penalized/constrained optimization. A partial least squares (PLS) with statistical significance testing acts as a supervisory-level filter to extract the most informative components of the network from a data set. Then, LASSO with extra weights on the smaller parameters identified in the first layer is employed to retain the main predictors and to set the smallest coefficients to zero. We present two case studies to compare the relative performance of DPLASSO and LASSO in terms of several metrics, such as sensitivity, specificity, and accuracy. The first case study employs a synthetic data set;it demonstrates that DPLASSO substantially improves network reconstruction in terms of accuracy and specificity. The second case study relies on simulated data sets for cell division cycle of fission yeast and shows that DPLASSO overall outperforms LASSO and PLS in terms of sensitivity, specificity, and accuracy. Combining PLS with statistical significance testing and LASSO provides good performance with respect to several metrics. DPLASSO is well suited for reconstruction of networks with low and moderate density. For high-density networks, high specificity is desired, making PLS a more suitable approach. © 1963-2012 IEEE.

关键词： Least squares approximations