38,090 research outputs found

    The dynamics of cryosorption pumping

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    Dynamics of cryosorption pumping of air, argon, and hydrogen by activated charcoa

    Weak nonmesonic decay spectra of hypernuclei

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    We compute one- and two-nucleon kinetic-energy spectra and opening-angle distributions for the nonmesonic weak decay of several hypernuclei, and compare our results with some recent data. The decaymics is described by transition potentials of the one-meson-exchange type, and the nuclear structure aspects by two versions of the independent-particle shell model (IPSM). In version IPSM-a, the hole states are treated as stationary, while in version IPSM-b the deep hole states are considered to be quasi-stationary and are described by Breit-Wigner distributions.Comment: 3 pages 2 figures. To be published in Nucl. Phys. A; Contribution to the NN2009 International Conference, Beijing, China, August 200

    Nonlinear dielectric response at the excess wing of glass-forming liquids

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    We present nonlinear dielectric measurements of glass-forming glycerol and propylene carbonate applying electrical fields up to 671 kV/cm. The measurements extend to sufficiently high frequencies to allow for the investigation of the nonlinear behavior in the regime of the so-far mysterious excess wing, showing up in the loss spectra of many glass formers as a second power law at high frequencies. Surprisingly, we find a complete lack of nonlinear behavior in the excess wing, in marked contrast to the alpha-relaxation where, in agreement with previous reports, a strong increase of dielectric constant and loss is found.Comment: 8 pages (including 3 pages Supplementary Information), 4 + 1 figures. Revised according to suggestions of referee

    Phase Transitions in a Two-Component Site-Bond Percolation Model

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    A method to treat a N-component percolation model as effective one component model is presented by introducing a scaled control variable p+p_{+}. In Monte Carlo simulations on 16316^{3}, 32332^{3}, 64364^{3} and 1283128^{3} simple cubic lattices the percolation threshold in terms of p+p_{+} is determined for N=2. Phase transitions are reported in two limits for the bond existence probabilities p=p_{=} and pp_{\neq}. In the same limits, empirical formulas for the percolation threshold p+cp_{+}^{c} as function of one component-concentration, fbf_{b}, are proposed. In the limit p==0p_{=} = 0 a new site percolation threshold, fbc0.145f_{b}^{c} \simeq 0.145, is reported.Comment: RevTeX, 5 pages, 5 eps-figure

    Spectral estimates of solar radiation intercepted by corn canopies

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    Reflectance factor data were acquired with a Landsat band radiometer throughout two growing seasons for corn (Zea mays L.) canopies differing in planting dates, populations, and soil types. Agronomic data collected included leaf area index (LAI), biomass, development stage, and final grain yields. The spectral variable, greenness, was associated with 78 percent of the variation in LAI over all treatments. Single observations of LAI or greenness have limited value in predicting corn yields. The proportions of solar radiation intercepted (SRI) by these canopies were estimated using either measured LAI or greenness. Both SRI estimates, when accumulated over the growing season, accounted for approximately 65 percent of the variation in yields. Models which simulated the daily effects of weather and intercepted solar radiation on growth had the highest correlations to grain yields. This concept of estimating intercepted solar radiation using spectral data represents a viable approach for merging spectral and meteorological data for crop yield models

    Runtime Verification of Temporal Properties over Out-of-order Data Streams

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    We present a monitoring approach for verifying systems at runtime. Our approach targets systems whose components communicate with the monitors over unreliable channels, where messages can be delayed or lost. In contrast to prior works, whose property specification languages are limited to propositional temporal logics, our approach handles an extension of the real-time logic MTL with freeze quantifiers for reasoning about data values. We present its underlying theory based on a new three-valued semantics that is well suited to soundly and completely reason online about event streams in the presence of message delay or loss. We also evaluate our approach experimentally. Our prototype implementation processes hundreds of events per second in settings where messages are received out of order.Comment: long version of the CAV 2017 pape

    SLE-type growth processes and the Yang-Lee singularity

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    The recently introduced SLE growth processes are based on conformal maps from an open and simply-connected subset of the upper half-plane to the half-plane itself. We generalize this by considering a hierarchy of stochastic evolutions mapping open and simply-connected subsets of smaller and smaller fractions of the upper half-plane to these fractions themselves. The evolutions are all driven by one-dimensional Brownian motion. Ordinary SLE appears at grade one in the hierarchy. At grade two we find a direct correspondence to conformal field theory through the explicit construction of a level-four null vector in a highest-weight module of the Virasoro algebra. This conformal field theory has central charge c=-22/5 and is associated to the Yang-Lee singularity. Our construction may thus offer a novel description of this statistical model.Comment: 12 pages, LaTeX, v2: thorough revision with corrections, v3: version to be publishe
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