990 resultados para Insertion de liens C-H


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PART I

The total cross-section for the reaction 21Ne(α, n)24Mg has been measured in the energy range 1.49 Mev ≤ Ecm ≤ 2.6 Mev. The cross-section factor, S(O), for this reaction has been determined, by means of an optical model calculation, to be in the range 1.52 x 1012 mb-Mev to 2.67 x 1012 mb-Mev, for interaction radii in the range 5.0 fm to 6.6 fm. With S(O) ≈ 2 x 1012 mb-Mev, the reaction 21Ne(α, n)24Mg can produce a large enough neutron flux to be a significant astrophysical source of neutrons.

PART II

The reaction12C(3He, p)14N has been studied over the energy range 12 Mev ≤ Elab ≤ 18 Mev. Angular distributions of the proton groups leading to the lowest seven levels in 14N were obtained.

Distorted wave calculations, based on two-nucleon transfer theory, were performed, and were found to be reliable for obtaining the value of the orbital angular momentum transferred. The present work shows that such calculations do not yield unambiguous values for the spectroscopic factors.

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A number of recent experiments have suggested the possibility of a highly inelastic resonance in K+p scattering. To study the inelastic K+p reactions, a 400 K exposure has been taken at the L.R.L. 25 inch bubble chamber. The data are spread over seven K+ momenta between 1.37 and 2.17 GeV/c.

Cross-sections have been measured for the reaction K+p → pK°π+ which is dominated by the quasi-two body channels K∆ and K*N. Both these channels are strongly peripheral, as at other momenta. The decay of the ∆ is in good agreement with the predictions of the rho-photon analogy of Stodolsky and Sakurai. The data on the K*p channel show evidence of both pseudo scalar and vector exchange.

Cross-sections for the final state pK+π+π- shows a strong contribution from the quasi-two body channel K*∆. This reaction is also very peripheral even at threshold. The decay angular distributions indicate the reaction is dominated as at higher momenta by a pion exchange mechanism. The data are also in good agreement with the quark model predictions of Bialas and Zalewski for the K* and ∆ decay.

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I. Ejercicios cortos de programación: - Enunciados. - Soluciones propuestas. II. Ejercicios largos: - Componentes electrónicos. - Hábitos de consumo: bebidas. - Emisora de radio. - Gasolinera. - Tienda. - Central eléctrica. - Ladrón Elca Comayor. - Cumbres de montaña. - Autopista. - Sala de juegos. - Farolas. - Pueblos de Guipúzcoa. - Olimpiadas. - Ventas S.A. - Accidentes de circulación. - Euskadi Irratia. - San Sebastián.

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I. Programazioko ariketa laburrak: - Enuntziatuak. - Soluzioen proposamenak. II. Ariketa luzeak: - Gailu elektronikoak. - Kontsumo ohiturak: edariak. - Irratsaioa. - Gasolindegia. - Denda. - Zentral elektrikoa. - Elca Comayor lapurra. - Medi igoerak. - Autopista. - Joko aretoa. - Farolak. - Herrien arteko distantziak. - Olinpiadak. - Ventas S.A. - Heriozko istripuak. - Euskadi Irratia. - San Sebastianak

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A obtenção de imagens usando tomografia computadorizada revolucionou o diagnóstico de doenças na medicina e é usada amplamente em diferentes áreas da pesquisa científica. Como parte do processo de obtenção das imagens tomográficas tridimensionais um conjunto de radiografias são processadas por um algoritmo computacional, o mais usado atualmente é o algoritmo de Feldkamp, David e Kress (FDK). Os usos do processamento paralelo para acelerar os cálculos em algoritmos computacionais usando as diferentes tecnologias disponíveis no mercado têm mostrado sua utilidade para diminuir os tempos de processamento. No presente trabalho é apresentada a paralelização do algoritmo de reconstrução de imagens tridimensionais FDK usando unidades gráficas de processamento (GPU) e a linguagem CUDA-C. São apresentadas as GPUs como uma opção viável para executar computação paralela e abordados os conceitos introdutórios associados à tomografia computadorizada, GPUs, CUDA-C e processamento paralelo. A versão paralela do algoritmo FDK executada na GPU é comparada com uma versão serial do mesmo, mostrando maior velocidade de processamento. Os testes de desempenho foram feitos em duas GPUs de diferentes capacidades: a placa NVIDIA GeForce 9400GT (16 núcleos) e a placa NVIDIA Quadro 2000 (192 núcleos).

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Tras la aparición de Arduino en el año 2002, emergió un fuerte movimiento concienciado con las plataformas libres, tanto en software como en hardware. Este movimiento junto con la filosofía del hágalo usted mismo (Do It Yourself) hizo que surgieran un sin fin de proyectos de todas las índoles, desde proyectos simples, como robots cartesianos, hasta proyecto más serios, como puede ser una máquina de control numérico. Todo esto es posible ya que junto con Arduino, han surgido infinidad de complementos y sensores asociados, fáciles de conseguir, baratos y que hacen que casi cualquier proyecto sea fácil de llevar a cabo y además económicamente viable. Lo que el autor de este proyecto fin de grado quiere hacer llegar al lector, es que un proyecto tan abrumador como puede ser una máquina de control numérico, puede ser perfectamente factible gracias a las bondades de una placa de un precio ínfimo y el ecosistema generado en torno a él.

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Este trabajo trata de un estudio profundo acerca del Cannabis y cómo ha ido evolucionando esta sustancia a lo largo de la historia, no solo desde un punto de vista antropológico en cuanto a los diferentes usos que se le han ido dando en diversas sociedades y tiempos, sino también cómo ha ido desarrollándose en materia legal y es ahí donde centro mi objeto de estudio en la regularización del Cannabis

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Phosphoglucose isomerase (PGI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. It is involved in glycolysis and in the regeneration of glucose-6-P molecules in the oxidative pentose phosphate pathway (OPPP). In chloroplasts of illuminated mesophyll cells PGI also connects the Calvin-Benson cycle with the starch biosynthetic pathway. In this work we isolated pgi1-3, a mutant totally lacking pPGI activity as a consequence of aberrant intron splicing of the pPGI encoding gene, PGI1. Starch content in pgi1-3 source leaves was ca. 10-15% of that of wild type (WT) leaves, which was similar to that of leaves of pgi1-2, a T-DNA insertion pPGI null mutant. Starch deficiency of pgi1 leaves could be reverted by the introduction of a sex1 null mutation impeding beta-amylolytic starch breakdown. Although previous studies showed that starch granules of pgi1-2 leaves are restricted to both bundle sheath cells adjacent to the mesophyll and stomata guard cells, microscopy analyses carried out in this work revealed the presence of starch granules in the chloroplasts of pgi1-2 and pgi1-3 mesophyll cells. RT-PCR analyses showed high expression levels of plastidic and extra-plastidic beta-amylase encoding genes in pgi1 leaves, which was accompanied by increased beta-amylase activity. Both pgi1-2 and pgi1-3 mutants displayed slow growth and reduced photosynthetic capacity phenotypes even under continuous light conditions. Metabolic analyses revealed that the adenylate energy charge and the NAD(P) H/NAD(P) ratios in pgi1 leaves were lower than those of WT leaves. These analyses also revealed that the content of plastidic 2-C-methyl-D-erythritol 4-phosphate (MEP)-pathway derived cytokinins (CKs) in pgi1 leaves were exceedingly lower than in WT leaves. Noteworthy, exogenous application of CKs largely reverted the low starch content phenotype of pgi1 leaves. The overall data show that pPGI is an important determinant of photosynthesis, energy status, growth and starch accumulation in mesophyll cells likely as a consequence of its involvement in the production of OPPP/glycolysis intermediates necessary for the synthesis of plastidic MEP-pathway derived hormones such as CKs.