20,446 research outputs found
Use of low-energy hydrogen ion implants in high-efficiency crystalline-silicon solar cells
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
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
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
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
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
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 -States in Quark Model and Baryon-Antibaryon Enhancements
We study the mass spectrum of the 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 and
are considered. In the spectrum
we find rather stable states which have the same quantum number with particle
resonances which are corresponding to the enhancement,
enhancement and enhancement with
spin- or . This imply these enhancements are NOT
experimental artifacts. The color-spin-flavor structures of ,
, and enhancements are revealed. The
existence of spin-
enhancements is predicted.Comment: 45 pages, 5 figure
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