2,706 research outputs found

    Annealing characteristics of amorphous silicon alloy solar cells irradiated with 1.00 MeV protons

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    Amorphous Si:H and amorphous Si sub x, Ge sub (1-x):H solar cells were irradiated with 1.00 MeV proton fluences in the range of 1.00E14 to 1.25E15 cm (exp -2). Annealing of the short circuit current density was studied at 0, 22, 50, 100, and 150 C. Annealing times ranged from an hour to several days. The measurements confirmed that annealing occurs at 0 C and the initial characteristics of the cells are restored by annealing at 200 C. The rate of annealing does not appear to follow a simple nth order reaction rate model. Calculations of the short-circuit current density using quantum efficiency measurements and the standard AM1.5 global spectrum compare favorably with measured values. It is proposed that the degradation in J sub sc with irradiation is due to carrier recombination through the fraction of D (o) states bounded by the quasi-Fermi energies. The time dependence of the rate of annealing of J sub sc does appear to be consistent with the interpretation that there is a thermally activated dispersive transport mechanism which leads to the passivation of the irradiation induced defects

    Probing the magnetic ground state of the molecular Dysprosium triangle

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    We present zero field muon spin lattice relaxation measurements of a Dysprosium triangle molecular magnet. The local magnetic fields sensed by the implanted muons indicate the coexistence of static and dynamic internal magnetic fields below T∗ 35T^* ~35 K. Bulk magnetization and heat capacity measurements show no indication of magnetic ordering below this temperature. We attribute the static fields to the slow relaxation of the magnetization in the ground state of Dy3. The fluctuation time of the dynamic part of the field is estimated to be ~0.55 μ\mus at low temperaturesComment: 5 pages, 5 figures, accepted for publication in Phys. Rev.

    The Nonlinear Cosmological Matter Power Spectrum with Massive Neutrinos I: The Halo Model

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    Measurements of the linear power spectrum of galaxies have placed tight constraints on neutrino masses. We extend the framework of the halo model of cosmological nonlinear matter clustering to include the effect of massive neutrino infall into cold dark matter (CDM) halos. The magnitude of the effect of neutrino clustering for three degenerate mass neutrinos with m_nu=0.9 eV is of order ~1%, within the potential sensitivity of upcoming weak lensing surveys. In order to use these measurements to further constrain--or eventually detect--neutrino masses, accurate theoretical predictions of the nonlinear power spectrum in the presence of massive neutrinos will be needed, likely only possible through high-resolution multiple particle (neutrino, CDM and baryon) simulations.Comment: v2: matches PRD versio

    Use of intravenous anti-D in patients with refractory and relapsed immune thrombocytopenic purpura

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    Objective: To determine the response to IV anti-D and its comparison with splenectomy as second line therapy in refractory and relapsed cases of ITP, in the Aga Khan University Hospital, Karachi. Methods: A total of 23 patients with chronic ITP were treated with either anti-D or splenectomy as second line treatment. The patients were assessed for time to achieve a response to second line treatment, duration ofresponse and adverse events. Results: There were 12 patients in the anti-D group and 11 in the splenectomy group. The mean platelet count at presentation was 9,000/cumm. The mean age was 8.9 years and 13.0 years and the male to female ratio was 1:1 and 1:1.2 in anti-D and splenectomy group respectively. 54.5% of the patient in the anti-D group responded compared to 81.8% in the splenectomy group. Median time to achieve a response was 7 days in the anti-D group and 1 day in the splenectomy group. Mean time to relapse was 87.8 days in the anti-D group and 55.4 days in the splenectomy group. No adverse events were recorded for any of the infusions of anti-D and none of the patients had more than 0.5 gm /dl fall in the hemoglobin level following anti-D infusion. Conclusion: It was thus concluded that Anti-D is a relatively safe, convenient and effective therapy for chronic ITP and can be used as a splenectomy sparing agent when treatment is clinically indicated

    Distibusi Bivalvia (Moluska) Di Danau Sipogas Kabupaten Rokan Hulu Provinsi Riau

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    The aims of this study was to determine distribution of Bivalvia (Mollusca) in Sipogas Lake Rokan Hulu Regency, Riau Province. The study was conducted in November to December 2014 with survey method. Sample collected by using eckman dredge with purposive random sampling, with four stations. Results showed, 1 species was found, it was Corbicula javanica with a total number of 77 individuals. The density was ranged from 17.78 to 64 individuals/m2, with distribution patterns on pattern of grouped distribution

    Precise Particle Tracking Against a Complicated Background: Polynomial Fitting with Gaussian Weight

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    We present a new particle tracking software algorithm designed to accurately track the motion of low-contrast particles against a background with large variations in light levels. The method is based on a polynomial fit of the intensity around each feature point, weighted by a Gaussian function of the distance from the centre, and is especially suitable for tracking endogeneous particles in the cell, imaged with bright field, phase contrast or fluorescence optical microscopy. Furthermore, the method can simultaneously track particles of all different sizes, and allows significant freedom in their shape. The algorithm is evaluated using the quantitative measures of accuracy and precision of previous authors, using simulated images at variable signal-to-noise ratios. To these we add a new test of the error due to a non-uniform background. Finally the tracking of particles in real cell images is demonstrated. The method is made freely available for non-commencial use as a software package with a graphical user-inferface, which can be run within the Matlab programming environment
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