13,374 research outputs found

    Collective spin waves in arrays of Permalloy nanowires with single-side periodically modulated width

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    We have experimentally and numerically investigated the dispersion of collective spin waves prop-agating through arrays of longitudinally magnetized nanowires with periodically modulated width. Two nanowire arrays with single-side modulation and different periodicity of modulation were studied and compared to the nanowires with homogeneous width. The spin-wave dispersion, meas-ured up to the third Brillouin zone of the reciprocal space, revealed the presence of two dispersive modes for the width-modulated NWs, whose amplitude of magnonic band depends on the modula-tion periodicity, and a set of nondispersive modes at higher frequency. These findings are different from those observed in homogeneous width NWs where only the lowest mode exhibits sizeable dis-persion. The measured spin-wave dispersion has been satisfactorily reproduced by means of dynam-ical matrix method. Results presented in this work are important in view of the possible realization of frequency tunable magnonic device

    The Microsoft 2017 Conversational Speech Recognition System

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    We describe the 2017 version of Microsoft's conversational speech recognition system, in which we update our 2016 system with recent developments in neural-network-based acoustic and language modeling to further advance the state of the art on the Switchboard speech recognition task. The system adds a CNN-BLSTM acoustic model to the set of model architectures we combined previously, and includes character-based and dialog session aware LSTM language models in rescoring. For system combination we adopt a two-stage approach, whereby subsets of acoustic models are first combined at the senone/frame level, followed by a word-level voting via confusion networks. We also added a confusion network rescoring step after system combination. The resulting system yields a 5.1\% word error rate on the 2000 Switchboard evaluation set

    Experimental verification of a Jarzynski-related information-theoretic equality using a single trapped ion

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    Most non-equilibrium processes in thermodynamics are quantified only by inequalities, however the Jarzynski relation presents a remarkably simple and general equality relating non-equilibrium quantities with the equilibrium free energy, and this equality holds in both classical and quantum regimes. We report a single-spin test and confirmation of the Jarzynski relation in quantum regime using a single ultracold 40Ca+^{40}Ca^{+} ion trapped in a harmonic potential, based on a general information-theoretic equality for a temporal evolution of the system sandwiched between two projective measurements. By considering both initially pure and mixed states, respectively, we verify, in an exact and fundamental fashion, the non-equilibrium quantum thermodynamics relevant to the mutual information and Jarzynski equality.Comment: 2 figure

    Identifying strongly correlated supersolid states on the optical lattice by quench-induced \pi-states

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    We consider the rapid quench of a one-dimensional strongly correlated supersolid to a localized density wave (checkerboard) phase, and calculate the first-order coherence signal following the quench. It is shown that unique coherence oscillations between the even and odd sublattice sites of the checkerboard are created by the quench, which are absent when the initial state is described by a Gutzwiller product state. This is a striking manifestation of the versatility of the far-from-equilbrium and nonperturbative collapse and revival phenomenon as a microscope for quantum correlations in complex many-body states. For the present example, this opens up the possibility to discriminate experimentally between mean-field and many-body origins of supersolidity.Comment: 6 pages of EPL2 style, 5 figure

    In-situ marginalisation : social impact of Chinese mega-projects

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    This study offers a detailed analysis of an under‐researched social problem of in‐situ marginalisation and its causes by drawing on the concept of state entrepreneurialism. Our empirical data stem from the Lingang mega project in Shanghai and one of its neighbourhoods named Neighbourhood No.57 where we find that the residents have not been relocated but are instead suffering from declining public services and environmental quality from surrounding industrial developments. The root cause of this problem is the municipal government’s prioritisation of its strategic objectives of economic development over the livelihood of local residents. The strategic vision of the municipality has led to mass relocation in its early phases of development but in its later stages leaves many residents waiting for relocation whilst being gradually surrounded by industrial developments. Despite continued residential complaints and petitions, in‐situ marginalisation is not resolved due to the institutional arrangement of Lingang, which has centralised planning and financing powers to newly created project‐oriented state organisation. Social responsibilities have been relegated to lower‐tiered governments in Lingang which have neither planning power nor the financial resources to resolve the problems of residents. By examining the case of Lingang, this paper provides a different analytical framework for explaining the social problems emerging from China’s mega urban developments

    Pillared two-dimensional metal-organic frameworks based on a lower-rim acid appended calix[4]arene

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    Solvothermal reactions of the lower-rim functionalized diacid calix[4]arene 25,27-bis(methoxycarboxylic acid)-26,28-dihydroxy-4-tert-butylcalix[4]arene (LH₂) with Zn(NO₃)₂•6H₂O and the dipyridyl ligands 4,4/-bipyridyl (4,4/-bipy), 1,2-di(4-pyridyl)ethylene (DPE) or 4,4/-azopyridyl (4,4/-azopy) afforded a series of 2-D structures of the formulae {[Zn(4,4/-bipy)(L)]•2¼DEF}n (1), {[Zn₂(L)(DPE)]•DEF}n (2) and {[Zn(OH₂)₂(L)(4,4/-azopy)]•DEF}n (3) (DEF = diethylformamide)

    Mechanical Properties And Creep Resistance Of Nickel Alloys After Complex Modification And Double Filtration

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    The paper presents the results of studies to determine the effect of complex surface and bulk modification and double filtration during mould pouring on the stereological parameters of macrostructure and mechanical properties of castings made from the post-production waste IN-713C and the MAR-247 nickel alloys. The evaluation covered the number of grains per 1mm2 of the sample surface area, the average area of grains and the shape index, hardness HB, tensile strength and resistance to high temperature creep. The results indicate the possibility of controlling the stereological parameters of macrostructure through application of several variants of the modification, controlling in this way also different low- and high-temperature properties. The positive effect of double filtration of the alloy during mould pouring on the metallurgical quality and mechanical properties of castings has also been emphasized
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