1,610 research outputs found
Study of 9Be+12C elastic scattering at energies near the Coulomb barrier
In this work, angular distribution measurements for the elastic channel were
performed for the 9Be+12C reaction at the energies ELab=13.0, 14.5, 17.3, 19.0
and 21.0 MeV, near the Coulomb barrier. The data have been analyzed in the
framework of the double folding S\~ao Paulo potential. The experimental elastic
scattering angular distributions were well described by the optical potential
at forward angles for all measured energies. However, for the three highest
energies, an enhancement was observed for intermediate and backward angles.
This can be explained by the elastic transfer mechanism.
Keywords: 9Be+12C, Elastic Scattering, S\~aoo Paulo Potential
6Li direct breakup lifetimes
alpha-d coincidence data were studied for the 6Li + 59Co reaction at E(lab) =
29.6 MeV. By using a kinematic analysis, it was possible to identify which
process, leading to the same final state, has the major contribution for each
of the selected angular regions. Contributions of the 6Li sequential and direct
breakup to the incomplete fusion/transfer process were discussed by considering
the lifetimes obtained by using a semiclassical approach, for both breakup
components.Comment: 5 pages, 4 figures, Invited Talk (Parrallel Sessions) of A. Szanto de
Toledo, prepared for the Proccedings of the 10th International Conference on
Nucleus-Nucleus Collisions, August 16-21, 2009, Beijing, China; submitted to
Nucl. Phys. A (Proceedings of NN2009
Avaliação do desempenho do puruí (Alibertia edulis L. Rich) A. Rich) na região de Manaus, AM.
As mudas de purui produzidas atraves de sementes possuem caracteristicas diferentes entre si. Observou-se que 50% das plantas iniciaram a producao a partir do segundo ano apos o plantio, indicando boa precocidade. No terceiro ano, cerca de 70% das plantas produziram frutos, destacando-se uma planta que produziu frutos maiores e em quantidade superiores as demais, apresentando boas caracteristicas para ser multiplicada assexuadamente.bitstream/item/83045/1/Pesquisa-17-1994.pd
Reaction mechanisms in the 6Li+59Co system
The reactions induced by the weakly bound 6Li projectile interacting with the
intermediate mass target 59Co were investigated. Light charged particles
singles and - coincidence measurements were performed at the near
barrier energies E_lab = 17.4, 21.5, 25.5 and 29.6 MeV. The main contributions
of the different competing mechanisms are discussed. A statistical model
analysis, Continuum-Discretized Coupled-Channels calculations and two-body
kinematics were used as tools to provide information to disentangle the main
components of these mechanisms. A significant contribution of the direct
breakup was observed through the difference between the experimental sequential
breakup cross section and the CDCC prediction for the non-capture breakup cross
section.Comment: 30 pages, 8 figure
Avaliação de espécies leguminosas na formação de cafezais no segmento da agricultura familiar no Acre.
Leguminosas quando consorciadas com o café e usadas como adubação verde podem contribuir fornecendo nitrogênio e proteção ao solo pela adição de matéria orgânica. O trabalho foi conduzido com o objetivo de avaliar o efeito do uso de leguminosas no sistema de produção de café, no segmento de agricultura familiar, visando promover a implantação e a manutenção dos cafezais de forma técnica e economicamente sustentável. O experimento foi conduzido no período de novembro de 2000 a abril de 2003, em delineamento experimental de blocos ao acaso em esquema de parcelas subdivididas, com quatro repetições. Os tratamentos utilizados nas parcelas foram as leguminosas (Stizolobium atterrimum, Cajanus cajan, Canavalia endiformis e Flemingia congesta) e a testemunha (sem leguminosa) e, nas subparcelas, duas doses de N (0 e 22 g de N por cova). A Flemingia congesta e a Mucuna aterrima foram as leguminosas que mais influenciaram positivamente a produtividade dos cafeeiros, independente da adubação nitrogenada. Em relação à testemunha, o aumento em produção foi de 109% quando utilizou-se a Flemingia congesta e 52% com a Mucuna aterrima. A Flemingia congesta foi também a leguminosa que melhor controlou as invasoras, dado o volume de fitomassa produzida e a possibilidade de 2 cortes durante um período de doze meses, evidenciando o potencial desta leguminosa na formação de novos cafezais no Acre. Por outro lado, a Canavalia ensiformis, leguminosa que é normalmente utilizada nas entrelinhas dos cafeeiros pelos cafeicultores, do Acre e de outras regiões produtoras, neste trabalho influenciou negativamente a altura das plantas, diâmetro da copa e crescimento dos cafeeiros
Projectile breakup dynamics for Li + Co: kinematical analysis of - coincidences
A study of the kinematics of the - coincidences in the Li +
Co system at a bombarding energy of MeV is presented.
With exclusive measurements performed over different angular intervals it is
possible to identify the respective contributions of the sequential projectile
breakup and direct projectile breakup components. A careful analysis using a
semiclassical approach of these processes provides information on both their
lifetime and their distance of occurrence with respect to the target. Breakup
to the low-lying (near-threshold) continuum is delayed, and happens at large
internuclear distances. This suggests that the influence of the projectile
breakup on the complete fusion process can be related essentially to direct
breakup to the Li high-lying continuum spectrum. %Comment: Revised version including new Fig.3 and Fig.4 with new CDCC
calculations. Accepted for publication at Eur. Phys. Jour. A. 11 pages, 6
figure
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