Caracterización morfológica de nanotubos de ZnO

Abstract

En este trabajo se presenta el procedimiento llevado a cabo para la síntesis de nanotubos de óxido de zinc (ZnO) y su correspondiente caracterización morfológica. Los nanotubos fueron sintetizados sobre sustratos previamente optimizados, los cuales se denominan "capa semilla" y también sobre vidrio, para efectos de comparación. La optimización de los substratos se realizó mediante el depósito de una película delgada de ZnO utilizando la técnica de rocío químico ultrasónico. El crecimiento de los nanotubos de ZnO se llevó a cabo mediante la técnica depósito por baño químico, en el cual, los substratos fueron sumergidos en dirección paralela al fondo del vaso de precipitado. Las muestras fueron estudiadas utilizando la microscopía de fuerza atómica para determinar sus características morfológicas. A diferencia de otros trabajos, la síntesis se realizó en un medio acuoso a partir del precursor de nitrato de zinc utilizando como controlador la monoetanolamina. Se observó que los nanotubos de forma hexagonal con tamaño uniforme crecieron únicamente sobre los substratos con el depósito de la capa semilla. La posición del substrato originó un crecimiento vertical y uniforme de los nanotubos en dirección normal al substrato. El tamaño promedio del diámetro de los nanotubos fue de 31.6 nm. y la razón de aspecto promedio de 2.59 nm.

In situ morphological characterization of soursop (Annona muricata L.) plants in Manabí, Ecuador

“…In base to the expressed by Franco and Hidalgo (2003) and Hernández (2013), about the variability we can suggest the existence of greater variability of the Ecuadorian soursop germplasm versus other germplasms such as the studied by Padmini et al (2013), who in the characterization of a germplasm of 448 soursop accessions in Sri Lanka, Asia, with the use of 45 characters, discarded the length of the leaf, the length of the petiole of the leaf, the shape of the apex and of the base of the leaf, the undulation of the leaf, and the color of the mature leaf, characters that instead were highly variable in the Ecuadorian germplasm.…”

“…This character is particularly important because is related to productivity and profitability, being priority in genetic improvement programs (Jameel et al, 2015). Based on the considerations about the variability expressed by Franco and Hidalgo (2003) and Hernández (2013), it can be suggested, that there is greater variability of the Ecuadorian soursop germplasm compared to the germplasm studied by Padmini et al (2013), in which 448 soursop accessions were characterized, discarded the length of the leaf, the length of the petiole of the leaf (due to low variation coefficient), the shape of the apex and the base of the leaf (in both case only one form), the margin of the leaf (entire %), and the color of the mature leaf (dark green 100 %), characters that were highly variable in the Ecuadorian germplasm. No significant correlation coefficients were observed between the morphological descriptors, except between the number of fruits and the canopy diameter, which showed a highly significant positive correlation, although with a medium coefficient (r = 0.54).…”

Characterization of mamey [Pouteria sapota (Jacq.) Moore & Stearn] in the Totonacapan Poblano region of Puebla, Mexico

“…However, there are few studies regarding variations of growth habits, tree shape, and leaf shape (Calderón et al, 2011). The morphological characterization of plant genetic resources is a procedure used to measure and know the genetic variability of a population, to differentiate plants, and to conserve genetic resources (Hernández, 2013). This study had the objective of morphologically characterizing mamey (P. sapota), using morphological variables of trees, leaves and fruits in 10 municipalities of the Totonacapan Poblano region, with the purposes of improvement and conservation.…”