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Proceedings of the 4th International Conference on
Nanostructures (ICNS4)12-14 March 2012, Kish Island, I.R. Iran
Abstract Book|INST| Sharif University of Technology|184
MOD
MOD 067
Morten Willatzen*, Benny Lassen
Mads Clausen Institute, University of Southern Denmark, Snderborg, DK-
6400, Denmark
Atomisc and Connuum Electromechanical Efects in
Nanostructures
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Computational methods for calculating strain and piezoelectric
elds in nanostructures are presented. Comparison is made between
continuum and valence force eld atomistic models and the validity
of the former in predicting strain elds for small nanostructures is
tested. An important conclusion is that a continuum model captures
well atomistic strain results; a fact that allows us to use a continuum
formulation even in cases where structure dimensions are in the
order of a few lattice constants. Since realistically grown structures
are subject to inhomogeneous concentration proling it is important
to determine the inuence of concentration grading effects for thestrain distribution and subsequently electronic eigenstates. We discuss
strain and piezoelectric results in the case where a spherical quantum
dot region is gradually proled from GaAs to InAs assuming the
concentration is a function of the distance to the quantum dot sphere
center. It is shown that quantum dot concentration gradings affect
strain elds and biaxial strains, and hence also electronic states and
optical properties. In the nal part of this work, a differential geometry
analysis of strain and electronic wave functions for a Mbius-shaped
quantum-dot structure is presented. We analyze conduction-band
states of Mbius structures and identify eigenstate connement
changes due to deformation potential effects especially for thicker
Mbius structures.
Keywords: Electromechanical effects; Nanostructures, Boundary
conditions.
MOD 068
SnO2 nanoparticles were synthesized by thermal decompositionmethod. Synthetic factors which led to tin oxide nanoparticles were
discussed. Taguchi analysis, a statistical experimental design method
was used to nd the effect of three parameters, molar concentration ratio
[nitrate solution/SnCl4
solution], temperature and time of calcinations,
on the size of SnO2
particles. The nanoparticles were characterized by
X-ray diffraction (XRD), transmission electron microscopy (TEM)
and UV-visible spectroscopy techniques. In this study was shown the
molar concentration ratio of [nitrate solution]/ [SnCl4
solution] was
the most inuencing parameter on the particles size. The resultant
nanoparticles were efcient catalysts in Knoevenagel condensation
reaction. The activities over SnO2
particles with different sizes are
compared. Moreover, the advantage of well ordered nanocrystallines
R. Memarzadeha, S. Ebrahimpourmoghaddamb, H. Sharghi,b S. Javadpourc*aDepartment of Materials Science and Engineering, Marvdasht Branch,Islamic
Azad University, Marvdasht, Iranb Department of Chemistry, College of Science, Shiraz University, Shiraz, IrancMaterials & Science Engineering Department, Shiraz University, Shiraz, Iran
Tin Oxide Nanoparcles by Taghuchi Robust Design Method
and Its Applicaon in Knoevenagel Condensaon
in catalyzing reactions was demonstrated. The various active methylene
group compounds, such as diethyl malonate, malononitrile and ethyl
acetoacetate were chosen to react with benzaldehyde. The catalyst
was completely recyclable without signicant loss of activity up to
ve reaction cycles, which confers its stability during reaction unlike
commercial catalysts.
Keywords: Tin oxide; Nanoparticles; Taguchi analysis; Knoevenagel
condensation.