8,934 research outputs found

    Orientation-dependent pseudomorphic growth of InAs for use in lattice-mismatched mid-infrared photonic structures

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    In this study, InAs was deposited on GaAs (100) and GaAs (111)B 2 degrees towardssubstrates for the purpose of differentiating the InAs growth mode stemming from strain and then analyzed using in-situ reflection high energy electron diffraction, scanning electron microscopy, Raman spectroscopy, reflectance spectroscopy, and atomic force microscopy. The procession of InAs deposition throughout a range of deposition conditions results in assorted forms of strain relief revealing that, despite lattice mismatch for InAs on GaAs (approximately 7%), InAs does not necessarily result in typical quantum dot/wire formation on (111) surfaces, but instead proceeds two-dimensionally due primarily to the surface orientation

    A HYPERBOLIC TANGENT YIELD FUNCTION OF FLORIDA CITRUS

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    This study models Florida citrus production as a function of the age profile of a given tree stock. The age relationship is estimated using a modified hyperbolic tangent function and the parameters is solved by Spatial Process Models and Maximum Likelihood approach. The estimation is based on the production data of four citrus varieties in 25 regions of Florida from 1992 to 2005. The results show smooth S-shaped yield curves of Florida citrus. This analysis offers yield function of citrus as the first step for statistical modeling of the risks associated with citrus cancers aimed at pricing insurance rates.yield function, citrus, hyperbolic tangent, insurance, spatial autoregressive, Demand and Price Analysis,

    Penguin-induced Radiative Baryonic B Decays Revisited

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    Weak radiative baryonic B decays BˉB1Bˉ2γ\bar B\to B_1\bar B_2\gamma mediated by the electromagnetic penguin process bsγb\to s\gamma are re-examined within the framework of the pole model. The meson pole contribution that has been neglected before is taken into account in this work. It is found that the intermediate KK^* contribution dominates in the Σpˉγ\Sigma\bar p\gamma mode and is comparable to the baryon pole effect in Λpˉγ\Lambda\bar p\gamma and ΞΛˉγ\Xi\bar\Lambda\gamma modes. The branching ratios for BΛpˉγB^-\to\Lambda\bar p\gamma and BΞ0ΣˉγB^-\to\Xi^0\bar\Sigma^-\gamma are of order 2.6×1062.6\times 10^{-6} and 6×1076\times 10^{-7}, respectively. The threshold enhancement effect in the dibaryon mass spectrum is responsible by the meson pole diagram. We also study the angular distribution of the baryon in the dibaryon rest frame. The baryon pole diagrams imply that the antibaryon tends to emerge in the direction of the photon in the baryon-pair rest frame. The predicted angular asymmetry agrees with experiment for BΛpˉγB^-\to\Lambda\bar p\gamma. Measurements of the correlation of the photon with the baryon allow us to discriminate between different models for describing the radiative baryonic B decays. For decays BΞΣˉγB\to\Xi\bar\Sigma\gamma, a large correlation of the photon to the Σˉ\bar\Sigma and a broad bump in the dibaryon mass spectrum are predicted.Comment: 10 pages, 4 figure

    An operational open-end file transfer protocol for mobile satellite communications

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    This paper describes an operational open-end file transfer protocol which includes the connecting procedure, data transfer, and relinquishment procedure for mobile satellite communications. The protocol makes use of the frame level and packet level formats of the X.25 standard for the data link layer and network layer, respectively. The structure of a testbed for experimental simulation of this protocol over a mobile fading channel is also introduced

    Simultaneous Measurement Imputation and Outcome Prediction for Achilles Tendon Rupture Rehabilitation

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    Achilles Tendon Rupture (ATR) is one of the typical soft tissue injuries. Rehabilitation after such a musculoskeletal injury remains a prolonged process with a very variable outcome. Accurately predicting rehabilitation outcome is crucial for treatment decision support. However, it is challenging to train an automatic method for predicting the ATR rehabilitation outcome from treatment data, due to a massive amount of missing entries in the data recorded from ATR patients, as well as complex nonlinear relations between measurements and outcomes. In this work, we design an end-to-end probabilistic framework to impute missing data entries and predict rehabilitation outcomes simultaneously. We evaluate our model on a real-life ATR clinical cohort, comparing with various baselines. The proposed method demonstrates its clear superiority over traditional methods which typically perform imputation and prediction in two separate stages

    Spectroscopy studies of straincompensated mid-infrared QCL active regions on misoriented substrates

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    In this work, we perform spectroscopic studies of AlGaAs/InGaAs quantum cascade laser structures that demonstrate frequency mixing using strain-compensated active regions. Using a three-quantum well design based on diagonal transitions, we incorporate strain in the active region using single and double well configurations on various surface planes (100) and (111). We observe the influence of piezoelectric properties in molecular beam epitaxy grown structures, where the addition of indium in the GaAs matrix increases the band bending in between injector regions and demonstrates a strong dependence on process conditions that include sample preparation, deposition rates, mole fraction, and enhanced surface diffusion lengths. We produced mid-infrared structures under identical deposition conditions that differentiate the role of indium(strain) in intracavity frequency mixing and show evidence that this design can potentially be implemented using other material systems
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