768 research outputs found

    Hybrid Design for Advanced Magnetic Recording Media : Combining Exchange-Coupled Composite Media with Coupled Granular Continuous Media

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    In order to enhance the performance of advanced granular recording media and understand the physics behind the mechanism of the reversal process, an atomistic spin-dynamics simulation is used to investigate theoretically the magnetic properties and the magnetization-reversal behavior for a composite media design. This model allows us to investigate the effect of the magnetostatic interaction and inter- and intralayer exchange coupling for a realistic system. The composite granular medium investigated consists of hard and soft composite layers in which the grains are well segregated with a continuous capping layer deposited to provide uniform exchange coupling. We present a detailed calculation aimed to reveal the reversal mechanism. In particular, the angular dependence of the critical field is investigated to understand the switching process. The calculations show a complex reversal mechanism driven by the magnetostatic interaction. It is also demonstrated, at high sweep rates consistent with the recording process, that thermal effects lead to a significant and irreducible contribution to the switching field distribution

    Size and shape analysis of error-prone shape data

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    We consider the problem of comparing sizes and shapes of objects when landmark data are prone to measurement error. We show that naive implementation of ordinary Procrustes analysis that ignores measurement error can compromise inference. To account for measurement error, we propose the conditional score method for matching configurations, which guarantees consistent inference under mild model assumptions. The effects of measurement error on inference from naive Procrustes analysis and the performance of the proposed method are illustrated via simulation and application in three real data examples. Supplementary materials for this article are available online

    Imperfect nesting and transport properties in unconventional density waves

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    We consider the effect of imperfect nesting in quasi-one dimensional unconventional density waves. The phase diagram is very close to those in a conventional DW. The linear and non-linear aspects of the electric conductivity are discussed. At T=0 the frequency dependent electric conductivity develops a small dip at low frequencies. The threshold electric field depends strongly on the imperfect nesting parameter, allowing us to describe the measured threshold electric field in the low temperature phase of the quasi-two dimensional organic conductor, alpha-(BEDT-TTF)_2KHg(SCN)_4 very well.Comment: 9 pages, 9 figure

    The controlled teleportation of an arbitrary two-atom entangled state in driven cavity QED

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    In this paper, we propose a scheme for the controlled teleportation of an arbitrary two-atom entangled state ϕ>12=agg>12+bge>12+ceg>12+dee>12|\phi>_{12}=a|gg>_{12}+b|ge>_{12}+c|eg>_{12}+d|ee>_{12} in driven cavity QED. An arbitrary two-atom entangled state can be teleported perfectly with the help of the cooperation of the third side by constructing a three-atom GHZ entangled state as the controlled channel. This scheme does not involve apparent (or direct) Bell-state measurement and is insensitive to the cavity decay and the thermal field. The probability of the success in our scheme is 1.0.Comment: 10 page

    Measurement of the branching ratio of the decay D^0 -> \pi^-\mu^+\nu relative to D^0 -> K^-\mu^+\nu

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    We present a new measurement of the branching ratio of the Cabibbo suppressed decay D^0\to \pi^-\mu^+\nu relative to the Cabibbo favored decay D^0\to K^-\mu^+\nu and an improved measurement of the ratio |\frac{f_+^{\pi}(0)}{f_+^{K}(0)}|. Our results are 0.074 \pm 0.008 \pm 0.007 for the branching ratio and 0.85 \pm 0.04 \pm 0.04 \pm 0.01 for the form factor ratio, respectively.Comment: 13pages, 3 figure

    Search for a strongly decaying neutral charmed pentaquark

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    We present a search for a charmed pentaquark decaying strongly to D()pD^{(*)-}p. Finding no evidence for such a state, we set limits on the cross section times branching ratio relative to DD^{*-} and DD^- under particular assumptions about the production mechanism.Comment: To be published in Physics Letters

    Determination of Population Structure of Wheat Core Collection for Association Mapping

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    The microsatellites, as one of the most robust markers for identification of wheat varieties, were used for assessment of genetic diversity and population structure to promote effective use of genetic resources. In this study, the set of 284 wheat varieties were genotyped using 30 microsatellite markers. The chosen SSR markers were located among almost all linkage groups and covered all three genomes. The genotypes used originate from 24 different breeding centers worldwide and are included in an extensive core collection of the Institute of Field and Vegetable Crops in Novi Sad, Serbia. The total number of detected alleles was 349 at all analyzed loci. The average number of detected allelic variant per locus was 11.5. The mean value of polymorphic information content was 0.68. According to the probability of data obtained by program Structure, the results have shown presence of 6 subpopulations within the studied set of genotypes. The population structure positively correlated to some extent with geographic origin. The available pedigree data were included for additional explanation of population structure. The results of this study should provide valuable information for future association studies using the diverse wheat breeding material

    Generating fuzzy rules by learning from olive tree transpiration measurement - An algorithm to automatize Granier sap flow data analysis

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    The present study aims at developing an intelligent system of automating data analysis and prediction embedded in a fuzzy logic algorithm (FAUSY) to capture the relationship between environmental variables and sap flow measurements (Granier method). Environmental thermal gradients often interfere with Granier sap flow measurements since this method uses heat as a tracer, thus introducing a bias in transpiration flux calculation. The FAUSY algorithm is applied to solve measurement problems and provides an approximate and yet effective way of finding the relationship between the environmental variables and the natural temperature gradient (NTG), which is too complex or too ill-defined for precise mathematical analysis. In the process, FAUSY extracts the relationships from a set of input–output environmental observations, thus general directions for algorithm-based machine learning in fuzzy systems are outlined. Through an iterative procedure, the algorithm plays with the learning or forecasting via a simulated model. After a series of error control iterations, the outcome of the algorithm may become highly refined and be able to evolve into a more formal structure of rules, facilitating the automation of Granier sap flow data analysis. The system presented herein simulates the occurrence of NTG with reasonable accuracy, with an average residual error of 2.53% for sap flux rate, when compared to data processing performed in the usual way. For practical applications, this is an acceptable margin of error given that FAUSY could correct NTG errors up to an average of 76% of the normal manual correction process. In this sense, FAUSY provides a powerful and flexible way of establishing the relationships between the environment and NTG occurrencesinfo:eu-repo/semantics/publishedVersio

    Search for Single Top Production at LEP

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    Single top production in e+e- annihilations is searched for in data collected by the L3 detector at centre-of-mass energies from 189 to 209 GeV, corresponding to a total integrated luminosity of 634 pb-1. Investigating hadronic and semileptonic top decays, no evidence of single top production at LEP is obtained and upper limits on the single top cross section as a function of the centre-of-mass energy are derived. Limits on possible anomalous couplings, as well as on the scale of contact interactions responsible for single top production are determined
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