3,771 research outputs found

    Study of drift-field solar cells damaged by low-energy protons Progress report, Jun. 15 - Aug. 10, 1965

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    Irradiation damage of drift-field solar cells by low energy protons - calibration of irradiation apparatus and monitoring equipmen

    Antiproton annihilation on light nuclei at very low energies

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    The recent experimental data obtained by the OBELIX group on pˉ\bar{p}D and pˉ4\bar{p}^4He total annihilation cross sections are analyzed. The combined analysis of these data with existing antiprotonic atom data allows, for the first time, the imaginary parts of the S-wave scattering lengths for the two nuclei to be extracted. The obtained values are: Ima0sc=[0.62±0.02(stat)±0.04(sys)]fmIm a^{sc}_0 = [- 0.62 \pm 0.02 ({stat}) \pm 0.04 ({sys})] fm for pˉ\bar{p}D and Ima0sc=[0.36±0.03(stat)0.11+0.19(sys)]fmIm a^{sc}_0 = [- 0.36\pm 0.03({stat})^{+0.19}_{-0.11}({sys})] fm for pˉ4\bar{p}^4He. This analysis indicates an unexpected behaviour of the imaginary part of the pˉ\bar{p}-nucleus S-wave scattering length as a function of the atomic weight A: Ima0sc|Im a^{sc}_0| (pˉ\bar{p}p) > Ima0sc|Im a^{sc}_0| (pˉ\bar{p}D) > Ima0sc|Im a^{sc}_0| (pˉ4\bar{p}^4He).Comment: 13 pages, 5 figure

    ExoMol molecular line lists XXX: a complete high-accuracy line list for water

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    A new line list for H2_216^{16}O is presented. This line list, which is called POKAZATEL, includes transitions between rotation-vibrational energy levels up to 41000 cm1^{-1} in energy and is the most complete to date. The potential energy surface (PES) used for producing the line list was obtained by fitting a high-quality ab initio PES to experimental energy levels with energies of 41000 cm1^{-1} and for rotational excitations up to J=5J=5. The final line list comprises all energy levels up to 41000 cm1^{-1} and rotational angular momentum JJ up to 72. An accurate ab initio dipole moment surface (DMS) was used for the calculation of line intensities and reproduces high-precision experimental intensity data with an accuracy close to 1 %. The final line list uses empirical energy levels whenever they are available, to ensure that line positions are reproduced as accurately as possible. The POKAZATEL line list contains over 5 billion transitions and is available from the ExoMol website (www.exomol.com) and the CDS database

    Avaliação de genótipos de milho no município de Brasiléia-Acre.

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    A cultura do milho no município de Brasiléia, assume significa tiva relevância sócio-econômica, contribuindo com 20,65% na produção global do Estado (CEPA/1988). Além de ser utilizado na alimentação humana e ração animal, o excedente da produção tem sido comercializado no mercado local, em Rio Branco e Cobija, cidade frobteiriça (Bolivia). A cultura apresenta problemas diversos: cultivares pouco produtivas, cultivo em consorcio, grandes espaçamentos entre plantas, cultivares de grande porte, índices elevados de acamamento, doenças, ocorrência de baixa produtividade. Estes problemas têm constituído em fatores limitantes a oferta de milho ao mercado, além de resultar no baixo retorno econômico da pequena produção. Com o objetivo de selecionar cultivares mais produtivas e resistentes aos principais problemas da região, a UEPAE de Rio Branco vem desenvolvendo trabalhos no Núcleo de Pesquisa -Quixadá, localizado em Brasiléia.bitstream/item/117388/1/1158.pd

    Hot Zero and Full Power Validation of PHISICS RELAP-5 Coupling

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    PHISICS is a reactor analysis toolkit developed over the last 3 years at the Idaho National Laboratory. It has been coupled with the reactor safety analysis code RELAP5-3D. PHISICS is aimed at providing an optimal trade off between needed computational resources (in the range of 10~100 computer processors) and accuracy. In fact, this range has been identified as the next 5 to 10 years average computational capability available to nuclear reactor design and optimization nuclear reactor cores. Detailed information about the individual modules of PHISICS can be found in [1]. An overview of the modules used in this study is given in the next subsection. Lately, the Idaho National Laboratory gained access plant data for the first cycle of a PWR, including Hot Zero Power (HZP) and Hot Full Power (HFP). This data provides the opportunity to validate the transport solver, the interpolation capability for mixed macro and micro cross section and the criticality search option of the PHISICS pack

    Experimental evidence of antiproton reflection by a solid surface

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    We report here experimental evidence of the reflection of a large fraction of a beam of low energy antiprotons by an aluminum wall. This derives from the analysis of a set of annihilations of antiprotons that come to rest in rarefied helium gas after hitting the end wall of the apparatus. A Monte Carlo simulation of the antiproton path in aluminum indicates that the observed reflection occurs primarily via a multiple Rutherford-style scattering on Al nuclei, at least in the energy range 1-10 keV where the phenomenon is most visible in the analyzed data. These results contradict the common belief according to which the interactions between matter and antimatter are dominated by the reciprocally destructive phenomenon of annihilation.Comment: 5 pages with 5 figure
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