eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3339
Nonlocal Interactions in DNA Molecules at Nano-Scale
M.R. Ejtehadi
ywjxuhtg@scientiaunknown.non
1
B. Eslami-Mossallam
jjjwmalj@scientiaunknown.non
2
Department of Physics,Sharif University of Technology
Department of Physics,Sharif University of Technology
In this paper, we try to explain the origin of the anomalous elastic behavior of nanometersized
DNA molecules, which has been observed in all-atom molecular dynamic simulations [A.K. Mazur,
Biophys. J. 2006]. It is shown that this anomalous behavior is a consequence of nonlocal interactions
between DNA base pairs and the intrinsic curvature of DNA. A nonlocal harmonic elastic rod model is
proposed, which can successfully describe the elastic behavior of short DNA molecules.
https://scientiairanica.sharif.edu/article_3339_c12a5b7a29a2d4e92372feb064c9581c.pdf
DNA
elasticity
Long-range interactions
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3340
A Comparative Study on Mechanical and Adhesion Properties of Calcinated and Non Calcinated Nanobioglass-Titania Nano Composite Coatings on Stainless Steel Substrates
M. S. Dadash
veiazeei@scientiaunknown.non
1
M. Nasr-Esfahani
iosriqfo@scientiaunknown.non
2
Reza Ebrahimi-Kahrizsangi
nxgqtxcu@scientiaunknown.non
3
Hojatollah Vali
xmrtemcf@scientiaunknown.non
4
Saeed Karbasi
ndvrukmv@scientiaunknown.non
5
Department of Materials and Engineering,Azad University
Department of Materials and Engineering,Azad University
Department of Materials Engineering,Azad University
Department of Materials Engineering,McGill University
Department of Biomedical Engineering,Isfahan University
Thick lms of calcinated and non calcinated nanobioglass(NBG)-titania nanocomposite
coatings were prepared on stainless steel substrates using an alkoxide sol-gel process. The prepared lms
were characterized by TEM, SEM, EDS, XRD and other methods. The composite lms obtained from
calcinated NBG particles were compared to the lms obtained from non calcinated NBG particles. Here,
we present a comparative study on the mechanical and adhesion properties of two types of lm (TiO2-
calcinated NBG and TiO2-non calcinated NBG). The prepared thick lms were smooth and free of macro
cracking, fracture or
aking. The grain size of these lms was uniform and its nano scale conrmed
using a TEM microscope. Adhesion tests were carried out according to the ASTM-D-3359-97 standard.
The results showed that both calcinated and non calcinated NBG-titania lms have very good adhesion
properties. The hardness of the prepared lms (TiO2-calcinated NBG and TiO2-non calcinated NBG)
was compared by using a micro hardness test method. The results veried that the presence of calcinated
NBG particles in a NBG-titania composite gradually enhanced the mechanical data of the prepared lms.
https://scientiairanica.sharif.edu/article_3340_6f1e1caf876a5ee2240b1ef56551ba3b.pdf
Nano bioglass (NBG)
Sol-gel process
Titania sol
Adhesion properties
Composite
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3341
A Dislocation-Based Model Considering Free Surface Theory Through HPT Process: Nano-Structured Ni
M. Kazeminezhad
fwqsnyrh@scientiaunknown.non
1
E. Hosseini
xuxipsdg@scientiaunknown.non
2
Department of Materials Science and Engineering,Sharif University of Technology
Department of Materials Science and Engineering,Sharif University of Technology
In this study, a dislocation-based model is presented for investigating the evolution of
microstructure and mechanical properties of thin lms during a wide range of straining. The model is
applied to the High Pressure Torsion (HPT) process of thin nickel disks that provides valuable information
on the evolution of material parameters during deformation. The model considers a free surface theory
for thin films and can explain the size effect phenomenon in agreement with previous reported trends in
literature.
https://scientiairanica.sharif.edu/article_3341_dbc5870d53a7e30ff32b5799f1a29067.pdf
Dislocation-based model
Free surface theory
Size effect phenomenon
HPT
thin film
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3342
Fabrication of Nanosized Cuprous Oxide Using Fehling's Solution
M. Kooti
lfzsbxek@scientiaunknown.non
1
L. Matouri
vwgyogkl@scientiaunknown.non
2
Department of Chemistry,Shahid Chamran University
Department of Chemistry,Shahid Chamran University
In this paper we describe a facile method for the synthesis of Cu2O nanoparticles by
reduction of Fehling's solution, using glucose as reducing agent. Copper sulfate is used as a precursor
with potassium sodium tartarate in an alkaline media to produce Fehling's solution. The precipitation
of Cu2O nanoparticles from this solution in the presence of glucose was controlled by addition of SLES
or Triton-X 100 as surfactants. The reactions have been carried out at 60C with high repeatability.
The purication process of the Cu2O product does not require expensive methods, since a solid product is
obtained from a reaction in liquid phase. The resulting Cu2O nanoparticles were characterized by X-Ray
Diraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX),
Transmission Electron Microscopy (TEM) and Fourier-transform infrared (FTIR) spectroscopy.
https://scientiairanica.sharif.edu/article_3342_cfe83863d0627833e5862db842417aae.pdf
Cu2O
Fehling's solution
Nanoparticles
Surfactants
SLES
Triton-X 100
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3343
Morphology and Mechanical Properties of Polyacrylonitrile/Multi-Walled Carbon Nanotube (PAN/MWNTs) Nanocomposite Electrospun Nanofibers
M. Yousefzadeh
feiswpkg@scientiaunknown.non
1
M. Amani-Tehran
oebcmygy@scientiaunknown.non
2
M. Latifi
rsmasiiw@scientiaunknown.non
3
S. Ramakrishan
hnltupjx@scientiaunknown.non
4
Department of Textile Engineering,Amirkabir University of Technology
Department of Textile Engineering,Amirkabir University of Technology
Department of Textile Engineering,Amirkabir University of Technology
Department of Textile Engineering,University of Surrey
In this research the morphology and mechanical properties of PAN/MWNTs nanobers are
studied. The electrospinning process is used to produce ber at micro and nano scale. The dispersion of
MWNTs in polymer solution is the key factor to obtain desirable properties in the nal product. Thus,
the dispersion condition is investigated using SEM images. The morphological study of ber mats show
that by increasing the amount of MWNTs in the polymer from 0 to 1 wt%, the surface roughness of bers
is increased. Increasing the percentage of MWNTs in ber improves the tensile stress at maximum load
for about 114% and modulus for about 40%.
https://scientiairanica.sharif.edu/article_3343_a3cdd0f9989c98a518d294fb5b4cbdec.pdf
Nanober
Electrospinning
Mechanical property
Carbon nanotube
Nanocomposite
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3344
Diffusion of Ionic Liquids into Elastomer/Carbon Nanotubes Composites and Tensile Mechanical Properties of Resulting Materials
Blaz Likozar
wckjmkgg@scientiaunknown.non
1
Faculty of Science,Azerbaijan State Oil Academy
In order to ensure better elastomer/functionalized Multi-Walled Carbon Nanotube
(MWCNT) compatibility and to enhance the dispersion, a series of ionic liquids has been tested in regard
to an improved interaction between elastomer and functionalized carbon nanotubes. We found that in
the presence of especially one ionic liquid, namely, 1-butyl-1-methylpyrrolidinium tetra
uoroborate, for
the hydrogenated nitrile elastomer, used as basic polymer, a 1.83 fold increase of elongation at break was
achieved with only 7 wt% ionic liquid loading. At this low concentration of ionic liquid the sample
can be stretched up to 508% without mechanical failure. The use of this ionic liquid additionally results
in high tensile strength (21.4 MPa) at low concentration (< 7 wt %) of ionic liquid. Energy-dispersive
X-ray spectrometric scanning electron microscopy conrmed the homogeneous distribution of ionic liquids
among nitrile elastomer chains by showing uniform signal belonging to
uorine in ionic liquid, when the
diffusion process of ionic liquid into nanocomposites was long enough (> 48 h) during the ionic liquid
absorption measurements. Transmission electron microscopic images confirmed the good dispersion of the
MWCNT along with the exfoliated structure of the CNTs in the rubber matrix.
https://scientiairanica.sharif.edu/article_3344_d6113be2407a5236442ece6a008ebba1.pdf
Nanocomposites
Functionalized multi-walled carbon nanotubes
Ionic liquid
Elastomer
Polymer
Diffusion coefficient
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3345
Structural and Magnetic Study of Active Screen Plasma Nitrided Fe73:5Si13:5B9Nb3Cu1 and Fe77Si11B9Nb2:4Cu0:6 Ribbons
Elmira Memarzadeh Lotfabad
nffvdngo@scientiaunknown.non
1
Hamid Reza Madaah Hosseini
qawtvjoa@scientiaunknown.non
2
Hossein Asghari Shivaee
riiaxqcz@scientiaunknown.non
3
Saied Roostaie
etjvgdux@scientiaunknown.non
4
Department of Materials Science and Engineering,Sharif University of Technology
Department of Materials Science and Engineering,Sharif University of Technology
Department of Materials Science and Engineering,Sharif University of Technology
Department of Materials Science and Engineering,Amirkabir University of Technology
The comparative study of Active Screen Plasma Nitriding (ASPN) treatment of two
Finemet-type alloys with the compositions of Fe73:5Si13:5B9Nb3Cu1 and Fe77Si11B9Nb2:4Cu0:6 was
investigated in dierent temperatures ranging from 410C to 560C. Dierential Scanning Calorimetry
(DSC), X-Ray Diractometery (XRD), Atomic Force Microscopy (AFM), Scanning Electron Microscopy
(SEM), electrical resistivity, microhardness measurements and magnetic characterization by a Vibrating
Sample Magnetometer (VSM) were utilized to characterize the treated samples. The comparison of
the DSC data for the alloys suggested that the smaller amount of Nb as a growth inhibitor shifted the
crystallization temperatures towards lower temperatures. Thus, the crystalline volume fraction and grain
size in each temperature for Fe77Si11B9Nb2:4Cu0:6 alloy increased compared to Fe73:5Si13:5B9Nb3Cu1 alloy.
The size of iron nitrides on the surface of the ribbons with the lower Si content was larger. The electrical
resistivity for the annealed and nitrided Fe77Si11B9Nb2:4Cu0:6 alloy was lower compared to the annealed
and nitrided Fe73:5Si13:5B9Nb3Cu1 alloy, due to the larger grain size and lower Si content of Fe(Si) phase
in Fe77Si11B9Nb2:4Cu0:6 alloy. The VSM results showed that the maximum saturation magnetization and
coercivity at 440C were obtained in Fe77Si11B9Nb2:4Cu0:6 alloy after nitriding under 75% H2 and 75%
N2 gas mixture, respectively.
https://scientiairanica.sharif.edu/article_3345_c59fe5aa1ec86624c9a972ad57d448e0.pdf
Fe-Si-Nb-B-Cu alloys
Comparative study
Crystallization
Active screen plasma nitriding
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3346
Qualitative Study of Nanoassembly Process: 2-D Molecular Dynamics Simulations
A. Meghdari
meghdari@sharif.edu
1
S. H. Mahboobi
ppcgrvbw@scientiaunknown.non
2
N. Jalili
kkkcxapa@scientiaunknown.non
3
F. Amiri
nzbqssvu@scientiaunknown.non
4
Department of Mechanical Engineering,Sharif University of Technology
Department of Materials and Engineering,Sharif University of Technology
Department of Materials and Engineering,Sharif University of Technology
Department of Materials and Engineering,Sharif University of Technology
Precise positioning of nanoclusters through manipulation in the presence of other clusters
is one of the main challenging tasks in nanoclusters assembly. Currently, the size of clusters which are
used as building blocks is decreasing to a few nanometers. As a result, the particle nature of the matter
has a crucial role in manipulator/cluster/substrate interactions. In order to understand and predict the
behavior of nanoclusters during the positioning process, it is, therefore, essential to have a deep insight
into the aforementioned nanoscale interactions. In this research, 2-D molecular dynamics simulations are
used to investigate such behaviors. Performing the planar simulations can provide a rather satisfactory
qualitative instrument for our aim while the computation time is considerably decreased in comparison
with 3-D simulations. The system considered here is made up of a tip, two clusters and a substrate. The
main focus here is on metallic nanoclusters. In order to study the behavior of the above system which
is made up of dierent transition metals, Nose-Hoover dynamics and Sutton-Chen interatomic potential
are used. Furthermore, the eect of the material characteristics, tip form and manipulation scheme on
the success of the process are examined. Such qualitative simulation studies can pave the pathway towards
certain nanopositioning scenarios when considering dierent working conditions before consuming largescale
computation time or high experimental expenses.
https://scientiairanica.sharif.edu/article_3346_0e3ac20814be671019b0c4e5a5256005.pdf
Metallic nanoclusters
Nanomanipulation
Molecular dynamics simulations
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3347
Controlling the Burst Eect of a Drug by Introducing Starch in the Structure of Magnetic Polyurethane Microspheres Containing Superparamagnetic Iron Oxide Nanoparticles
M. Mahmoudi
okvxsacr@scientiaunknown.non
1
Sophie Laurent
wvtxchme@scientiaunknown.non
2
Department of Science,University of Tehran
Department of Chemistry,Institut Henri poincare
The aim of this research is to prepare superparamagnetic polyurethane microspheres using
SPIONs. Theophylline was used as a drug and the various stoichiometric ratios of isocyanate/polyol were
studied to assess their application as a targeting delivery system. Magnetic polyurethane microspheres
containing superparamagnetic iron oxide nanoparticles loaded with theophylline were prepared by the water
in oil in water emulsion technique. The ratio of hexamethylenediisocyanate and polyol ("-polycaprolactone
and starch) was modied and the release of theophylline was determined for a period of 20 days. These
microspheres were characterized by TEM, SEM, FTIR and magnetometry. The microscopy images show
the morphological shape of the superparamagnetic microspheres with an average size of 5 m. The FTIR
and the magnetometry confirmed the presence of superparamagnetic nanoparticles in the microspheres.
The release of theophylline was studied and dosed by UV spectrophotometer. With the use of PCL with
a low molecular weight or in the presence of starch in the structure of polyurethane, the burst effect
of drug is decreased. Finally, a SEM study showed an important degradation of the microspheres after
the release process. The use of starch as a polyol caused significant improvement in burst effect of the
superparamagnetic polyurethane microspheres.
https://scientiairanica.sharif.edu/article_3347_89ec2226ec7d03964bccd711e267caba.pdf
Superparamagnetic iron oxide nanoparticles
Polyurethane
Magnetic microspheres
Theophylline
eng
Sharif University of Technology
Scientia Iranica
1026-3098
2345-3605
2010-06-01
17
1
3348
Tip Geometry Eects in Surface Characterization with Amplitude Modulation AFM
A. Meghdari
meghdari@sharif.edu
1
Hosein Nejat Pishkenari
oiywtgcd@scientiaunknown.non
2
Department of Mechanical Engineering,Sharif University of Technology
Department of Mechanical Engineering,Sharif University of Technology
In the present work, characterization of the surface trenches and vacancies with Amplitude
Modulation AFM (AM-AFM) using Molecular Dynamics (MD) is simulated and the eects of the tip shape
on the resulting images are investigated. The simulated system includes a recently developed gold coated
AFM probe which interacts with a sample including a surface trench or a single-atom vacancy. In order
to examine the behavior of the above system, including dierent transition metals, a Molecular Dynamics
(MD) simulation with Sutton-Chen (SC) interatomic potential is used. Special attention is dedicated to
the study of tip geometry eects such as the tip apex radius, the tip cone angle, the probe tilt angle, the tip
apex atoms number, and the tip axis direction with respect to the FCC lattice structure on the resulting
images.
https://scientiairanica.sharif.edu/article_3348_1a3ee40c2c41feec53bd795f7167ea9a.pdf
Surface trench characterization
Amplitude modulation AFM
Tip shape eects