20,446 research outputs found

    Use of low-energy hydrogen ion implants in high-efficiency crystalline-silicon solar cells

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    The use of low-energy hydrogen implants in the fabrication of high-efficiency crystalline silicon solar cells was investigated. Low-energy hydrogen implants result in hydrogen-caused effects in all three regions of a solar cell: emitter, space charge region, and base. In web, Czochralski (Cz), and floating zone (Fz) material, low-energy hydrogen implants reduced surface recombination velocity. In all three, the implants passivated the space charge region recombination centers. It was established that hydrogen implants can alter the diffusion properties of ion-implanted boron in silicon, but not ion-implated arsenic

    Deductive Verification of Unmodified Linux Kernel Library Functions

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    This paper presents results from the development and evaluation of a deductive verification benchmark consisting of 26 unmodified Linux kernel library functions implementing conventional memory and string operations. The formal contract of the functions was extracted from their source code and was represented in the form of preconditions and postconditions. The correctness of 23 functions was completely proved using AstraVer toolset, although success for 11 functions was achieved using 2 new specification language constructs. Another 2 functions were proved after a minor modification of their source code, while the final one cannot be completely proved using the existing memory model. The benchmark can be used for the testing and evaluation of deductive verification tools and as a starting point for verifying other parts of the Linux kernel.Comment: 18 pages, 2 tables, 6 listings. Accepted to ISoLA 2018 conference. Evaluating Tools for Software Verification trac

    Higgs Triplets, Decoupling, and Precision Measurements

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    Electroweak precision data has been extensively used to constrain models containing physics beyond that of the Standard Model. When the model contains Higgs scalars in representations other than SU(2) singlets or doublets, and hence rho not equal to one at tree level, a correct renormalization scheme requires more inputs than the three needed for the Standard Model. We discuss the connection between the renormalization of models with Higgs triplets and the decoupling properties of the models as the mass scale for the scalar triplet field becomes much larger than the electroweak scale. The requirements of perturbativity of the couplings and agreement with electroweak data place strong restrictions on models with Higgs triplets. Our results have important implications for Little Higgs type models and other models with rho not equal to one at tree level.Comment: 23 page

    Computational Aspects of Optional P\'{o}lya Tree

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    Optional P\'{o}lya Tree (OPT) is a flexible non-parametric Bayesian model for density estimation. Despite its merits, the computation for OPT inference is challenging. In this paper we present time complexity analysis for OPT inference and propose two algorithmic improvements. The first improvement, named Limited-Lookahead Optional P\'{o}lya Tree (LL-OPT), aims at greatly accelerate the computation for OPT inference. The second improvement modifies the output of OPT or LL-OPT and produces a continuous piecewise linear density estimate. We demonstrate the performance of these two improvements using simulations

    Miraculous Survival of Three Trapping Miners by Drinking High Mineral Mine Water for 25

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    Little is known that how long a human been can survive a complete starvation. There were dozens of miners who lost their lives in a coal mine disaster at Qinglong,Guizhou,China in June 2009, only three of them were rescued 25 days later after they had been trapped in a coal mine 600 meters underground. They maintained their lives only by drinking mineral water in the mine, which created a miracle of life. We reported here on this life miracle in relation to high mineral mine water

    AMPHIBIAN DISTRIBUTION IN THE GEORGIA SEA ISLANDS: IMPLICATIONS FROM THE PAST AND FOR THE FUTURE

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    We summarized amphibian distributions for 12 coastal islands in Georgia, USA. Occurrence among islands was correlated with life history traits, habitats, island size, distance to other islands, and island geological age. Species’ distributions were determined from published literature. Island sizes and vegetation types were derived from 2011 Georgia Department of Natural Resources habitat maps, which included both federal and state vegetation classification systems. Species occurring on more islands tended to have greater total reproductive output (i.e., life span >4 years, and annual egg production >1,000 eggs) and adults had tolerance of brackish environs. Larger islands had great­er area of freshwater wetlands, predominantly short hydroperiod (<6 months). Species tied to long hydroperiod wetlands (>6 months) were more restricted in their distribution across islands. Overall, larger islands supported more species, but the correlation was weaker for geologically younger Ho­locene islands (age <11,000 years). While Euclidean distance between islands does not necessarily preclude inter-island dispersal, inhospitable habitat for amphibians (brackish tidal marshes and creeks interspersed with wide rivers) suggests that inter-island dispersal is very limited. The paucity of recent occurrence data for amphibians in this dynamic coastal region, let alone standardized annual moni­toring data, hinders efforts to model species’ vulnerability in a region susceptible to sea level rise and development pressure. The most common survey method, standardized amphibian vocal surveys, will detect Anuran reproductive efforts, but is unlikely to ascertain if breeding was successful or to detect salamanders. While it will not replace actual population data, consideration of critical life-history traits and breeding habitat availability can be used to direct management to support long-term species per­sistence in changing environs. Even common amphibians in coastal conservation areas of Georgia are vulnerable to increasing population isolation caused by unsuitable habitat

    Spectroscopy of q3qˉ3\rm{q}^3\bar{\rm{q}}^3-States in Quark Model and Baryon-Antibaryon Enhancements

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    We study the mass spectrum of the q3qˉ3\rm{q}^3\bar{\rm{q}}^3 mesons both from the quark model with triquark correlations and from common quark model with colormagnetic interactions and with relative S-waves between quarks. Two cluster configurations (q3)(qˉ3)(\rm{q}^3)-(\bar{\rm{q}}^3) and (q2qˉ)(qqˉ2)(\rm{q}^2\bar{\rm{q}})-(\rm{q}\bar{\rm{q}}^2) are considered. In the spectrum we find rather stable states which have the same quantum number with particle resonances which are corresponding to the ppˉp\bar{p} enhancement, pΛˉp\bar{\Lambda} enhancement and ΛΛˉ\Lambda\bar{\Lambda} enhancement with spin-0\mathbf{0} or 1\mathbf{1}. This imply these enhancements are NOT experimental artifacts. The color-spin-flavor structures of ppˉp\bar{p}, pΛˉp\bar{\Lambda}, and ΛΛˉ\Lambda\bar{\Lambda} enhancements are revealed. The existence of spin-1\mathbf{1} ΛΛˉ,pΛˉ,ppˉ\Lambda\bar{\Lambda}, p\bar{\Lambda}, p\bar{p} enhancements is predicted.Comment: 45 pages, 5 figure
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