62,701 research outputs found

    Magnetophoresis of nonmagnetic particles in ferrofluids

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    Ferrofluids containing nonmagnetic particles are called inverse ferrofluids. On the basis of the Ewald-Kornfeld formulation and the Maxwell-Garnett theory, we theoretically investigate the magnetophoretic force exerting on the nonmagnetic particles in inverse ferrofluids due to the presence of a nonuniform magnetic field, by taking into account the structural transition and long-range interaction. We numerically demonstrate that the force can be adjusted by choosing appropriate lattices, volume fractions, geometric shapes, and conductivities of the nonmagnetic particles, as well as frequencies of external magnetic fields.Comment: 24 pages, 7 figure

    Searching for high-KK isomers in the proton-rich A∼80A\sim80 mass region

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    Configuration-constrained potential-energy-surface calculations have been performed to investigate the KK isomerism in the proton-rich A∼80A\sim80 mass region. An abundance of high-KK states are predicted. These high-KK states arise from two and four-quasi-particle excitations, with Kπ=8+K^{\pi}=8^{+} and Kπ=16+K^{\pi}=16^{+}, respectively. Their excitation energies are comparatively low, making them good candidates for long-lived isomers. Since most nuclei under studies are prolate spheroids in their ground states, the oblate shapes of the predicted high-KK states may indicate a combination of KK isomerism and shape isomerism

    Semantic Wide and Deep Learning for Detecting Crisis-Information Categories on Social Media

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    When crises hit, many flog to social media to share or consume information related to the event. Social media posts during crises tend to provide valuable reports on affected people, donation offers, help requests, advice provision, etc. Automatically identifying the category of information (e.g., reports on affected individuals, donations and volunteers) contained in these posts is vital for their efficient handling and consumption by effected communities and concerned organisations. In this paper, we introduce Sem-CNN; a wide and deep Convolutional Neural Network (CNN) model designed for identifying the category of information contained in crisis-related social media content. Unlike previous models, which mainly rely on the lexical representations of words in the text, the proposed model integrates an additional layer of semantics that represents the named entities in the text, into a wide and deep CNN network. Results show that the Sem-CNN model consistently outperforms the baselines which consist of statistical and non-semantic deep learning models

    Consistency of shared reference frames should be reexamined

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    In a recent Letter [G. Chiribella et al., Phys. Rev. Lett. 98, 120501 (2007)], four protocols were proposed to secretly transmit a reference frame. Here We point out that in these protocols an eavesdropper can change the transmitted reference frame without being detected, which means the consistency of the shared reference frames should be reexamined. The way to check the above consistency is discussed. It is shown that this problem is quite different from that in previous protocols of quantum cryptography.Comment: 3 pages, 1 figure, comments are welcom

    Thermal and non-thermal emission in the Cygnus X region

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    Radio continuum observations detect non-thermal synchrotron and thermal bremsstrahlung radiation. Separation of the two different emission components is crucial to study the properties of diffuse interstellar medium. The Cygnus X region is one of the most complex areas in the radio sky which contains a number of massive stars and HII regions on the diffuse thermal and non-thermal background. More supernova remnants are expected to be discovered. We aim to develop a method which can properly separate the non-thermal and thermal radio continuum emission and apply it to the Cygnus X region. The result can be used to study the properties of different emission components and search for new supernova remnants in the complex. Multi-frequency radio continuum data from large-scale surveys are used to develop a new component separation method. Spectral analysis is done pixel by pixel for the non-thermal synchrotron emission with a realistic spectral index distribution and a fixed spectral index of beta = -2.1 for the thermal bremsstrahlung emission. With the new method, we separate the non-thermal and thermal components of the Cygnus X region at an angular resolution of 9.5arcmin. The thermal emission component is found to comprise 75% of the total continuum emission at 6cm. Thermal diffuse emission, rather than the discrete HII regions, is found to be the major contributor to the entire thermal budget. A smooth non-thermal emission background of 100 mK Tb is found. We successfully make the large-extent known supernova remnants and the HII regions embedded in the complex standing out, but no new large SNRs brighter than Sigma_1GHz = 3.7 x 10^-21 W m^-2 Hz^-1 sr^-1 are found.Comment: 9 pages, 5 figures, accepted by A&A. The quality of the figures is reduced due to file size limit of the websit

    Optimal Controlled Teleportation

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    We give the analytic expressions of maximal probabilities of successfully controlled teleportating an unknown qubit via every kind of tripartite states. Besides, another kind of localizable entanglement is also determined. Furthermore, we give the sufficient and necessary condition that a three-qubit state can be collapsed to an EPR pair by a measurement on one qubit, and characterize the three-qubit states that can be used as quantum channel for controlled teleporting a qubit of unknown information with unit probability and with unit fidelity.Comment: 4 page

    Probing polymer chain constraint and synergistic effects in nylon 6-clay nanocomposites and nylon 6-silica flake sub-micro composites with nanomechanics

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    In this study, we report that a synergistic effect exists in the surface mechanical properties of nylon 6–clay nanocomposites (NC) that can be shown by nanomechanical testing. The hardness, elastic modulus, and nanoindentation creep behavior of nylon 6 and its nanocomposites with different filler loading produced by melt compounding were contrasted to those of model nylon 6 sub-microcomposites (SMC) reinforced by sub-micro-thick silica flakes in which constraint cannot occur due to the difference in filler geometry. Polymer chain constraint was assessed by the analysis of nanoindentation creep data. Time-dependent creep decreased with increasing the filler loading in the NC consistent with the clay platelets exerting a constraint effect on the polymer chains which increases with filler loading. In contrast, there was no evidence of any reduced time-dependent creep for the SMC samples, consistent with a lack of constraint expected due to much lower aspect ratio of the silica flake
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