Materials Literature
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A systematic manipulation of the morphology and the optical emission properties of MOVPE grown ensembles of InAs/InP quantum dots is demonstrated by changing the growth kinetics parameters. Under non-equilibrium conditions of a comparatively higher growth rate and low growth temperature, the quantum dot density, their…
Layered organic conductors (BEDO-TTF)_2ReO_4*H_2O (metal) and (BEDT-TTF)_xDy(NO_3)_z (paramagnetic insulator) are studied by CW-EPR and SQUID methods. A correlation in resonance and transport properties of both compounds is attributed to a similar mechanism of fine anion ordering (AO) at T_AO=200 K. Due to the hydroge…
We investigated the structural and dynamical properties of a tetrahedrally coordinated crystalline ice from first principles based on density functional theory within the generalized gradient approximation with the projected augmented wave method. First, we report the structural behaviour of ice at finite temperatures…
Crystalline bilayers of charged colloidal suspensions which are confined between two parallel plates and sheared via a relative motion of the two plates are studied by extensive Brownian dynamics computer simulations. The charge-stabilized suspension is modeled by a Yukawa pair potential. The unsheared equilibrium con…
The low-energy part of the vibration spectrum in PbMg$_{1/3}$Nb$_{2/3}$O$_3$ (PMN) relaxor ferroelectric has been studied by neutron scattering above and below the Burns temperature, T$_d$. The transverse acoustic and the lowest transverse optic phonons are strongly coupled and we have obtained a model for this coupli…
This paper presents a novel method for preparation of raspberry-like organic−inorganic hybrid microspheres with PMMA as core and nanosilica particles as shell. A cationic monomer, 2-(methacryloyl)ethyltrimethylammonium chloride (MTC), was used as an auxiliary monomer, and nanosilica particles were deposited onto the s…
An electrochemical method is developed to quantitatively modify and spectroscopically monitor the size and shape of Ag nanotriangles fabricated by nanosphere lithography (NSL) on an indium tin oxide (ITO) electrode surface. AFM and SEM results demonstrate that the preferential order of electrochemical oxidation for a…
Research in diatom biology has entered the postgenomic era since the recent completion of the Thalassiosira pseudonana genome project. However, the molecular tools available for genetic manipulation of diatoms are still sparse, impeding the functional analysis of diatom genes in vivo. Here we describe the first method…
We report a synthesis of discrete, single-crystal, defect-free, and hexagonal Bi2Te3 nanoplatelets using a high-temperature organic solution approach, and we demonstrate a two-step epitaxial growth of the cylindrical strings of Bi2Te3 nanoplatelets on the surface of the Te rod by packing them along c-axis in a top-bot…
Self-heating in deep submicron transistors (e.g., silicon-on-insulator and strained-Si) and thermal engineering of many nanoscale devices such as nanocalorimeters and high-density thermomechanical data storage are strongly influenced by thermal conduction in ultra-thin silicon layers. The lateral thermal conductivity…
The molecular structure, photochemistry, and device physics of conjugated polymers have been investigated by single-molecule spectroscopy (SMS), using the unique ability of this technique to unravel complex spectra and dynamics. Surprisingly efficient and directional electronic energy funneling was observed for conjug…
Abstract Micron‐sized monodisperse superparamagnetic polyglycidyl methacrylate (PGMA) particles with functional amino groups were prepared by a process involving: (1) preparation of parent monodisperse PGMA particles by the dispersion polymerization method, (2) chemical modification of the PGMA particles with ethylene…
We report here an electrodeposition route for the preparation of oriented and well-defined ZnO nanostructures by kinetically controlling the growth rates of various facets of the deposit by appropriate capping agents. We demonstrated that adsorption of Cl(-) takes places preferentially onto the (0001) planes to hinder…
There has been considerable recent interest in the design of diluted magnetic semiconductors, with a particular focus on the exploration of different semiconductor hosts. Among these, the oxide-based diluted magnetic semiconductors are attracting increasing attention, following reports of room temperature ferromagneti…
Single-wall carbon nanotube field-effect transistors (CNFETs) have been shown to behave as Schottky barrier (SB) devices. It is not clear, however, what factors control the SB size. Here we present the first statistical analysis of this issue. We show that a large data set of more than 100 devices can be consistently…
Abstract Summary: An original direct melt extrusion processing of nylon 6/clay nanocomposites was reported based on pristine (Na + ‐based) montmorillonite as well as a simple approach using a typical two‐screw extruder. By the application of intercalation agents as the thermodynamic assistants, this method is as an ap…
Abstract A series of new side‐chain cholesteric elastomers derived from cholesteryl 4‐(10‐undecylen‐1‐yloxy)‐4′‐ethoxybenzoate and phenyl 4,4′‐bis(10‐undecylen‐1‐yloxybenzoyloxy‐ p ‐ethoxybenzoate) was synthesized. The chemical structures of the monomers were confirmed by elemental analyses, Fourier transform infrared…
The variations of X-ray diffraction intensities from a crystal in the presence of a permanent external electric field is modeled analytically using a first-order stationary perturbation theory. The change in a crystal, induced by an external electric field, is separated into two contributions. The first one is related…
Helicobacter pylori has been implicated in the etiology of stomach cancer and ulcers. The activity of total extract and polarfraction of Iranian medicinal plants Dracocephalum moldavica, Lavandula angustifolia, Rosmarinus officinalis, Salvia officinalis, Teucrium polium, Thymus daenensis and Zataria multiflora from th…
Abstract Summary: The molecular dynamics of polymer melts with molecular weights above their critical values have been described by a power law dependence of the spin‐lattice relaxation time on the Larmor frequency. Three different regimes of power laws describing the relaxation dispersion of polymers for the chain mo…