1,318 research outputs found
Spin-Exchange Interaction in ZnO-based Quantum Wells
Wurtzitic ZnO/(Zn,Mg)O quantum wells grown along the (0001) direction permit
unprecedented tunability of the short-range spin exchange interaction. In the
context of large exciton binding energies and electron-hole exchange
interaction in ZnO, this tunability results from the competition between
quantum confinement and giant quantum confined Stark effect. By using
time-resolved photoluminescence we identify, for well widths under 3 nm, the
redistribution of oscillator strengths between the A and B excitonic
transitions, due to the enhancement of the exchange interaction. Conversely,
for wider wells, the redistribution is cancelled by the dominant effect of
internal electric fields, which dramatically reduce the exchange energy.Comment: 14 pages, 3 figure
Seleção de épocas de plantio para minimizar o efeito de veranico para a cultura do milho: nota preliminar.
Graus-dia estimado com diferentes valores de temperatura base na cultura do milho (Zea mays L.).
Análise de interação de data de plantio, probabilidade de chuvas e consumo de água pela cultura do milho: nota preliminar.
Estimativa do período de florescimento e maturidade fisiólogica da cultura do sorgo por meio de graus-dias, calculado com diferentes valores de temperatura base.
Compressibility and structural stability of ultra-incompressible bimetallic interstitial carbides and nitrides
We have investigated by means of high-pressure x-ray diffraction the
structural stability of Pd2Mo3N, Ni2Mo3C0.52N0.48, Co3Mo3C0.62N0.38, and
Fe3Mo3C. We have found that they remain stable in their ambient-pressure cubic
phase at least up to 48 GPa. All of them have a bulk modulus larger than 330
GPa, being the least compressible material Fe3Mo3C, B0 = 374(3) GPa. In
addition, apparently a reduction of compressibility is detected as the carbon
content increased. The equation of state for each material is determined. A
comparison with other refractory materials indicates that interstitial nitrides
and carbides behave as ultra-incompressible materials.Comment: 14 pages, 3 figures, 1 tabl
Descripción morfológica de una nueva anomalía arterial coronaria en el hamster sirio Mesocricetus auratus (Waterhouse, 1839): interpretaciones genéticas y filogenéticas
Efeito da unidade do solo na germinação de sementes de milho tratadas com inseticidas e controle da lagarta do cartucho, Spodoptera frugiperda (Smith).
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