Search results for "nanostructure"

Nonlinear Transport in Hybrid Polypyrrole–Gold Nanostructures

2010

We have studied charge transport in nanometer scale films of polypyrrole (PPy) that were grown electrochemically onto discontinuous ultrathin films of gold. The gold films consisted of 100 nm size islands, separated from each other by nanometer-size gaps. The thickness of PPy can be varied from 30 to 200 nm. The I-V characteristics of these hybrid PPy-Au nanostructures show strong non-linearity at low temperatures, and in particular for the more insulating samples. The hopping transport is further verified from the log / versus V-1/4 plots. Furthermore, the I-V data follow an empirical relation dlog//dV(1/4) similar to T-1/2.

Mechanical, degradation and drug-release behavior of nano-grained Fe-Ag composites for biomedical applications.

2018

Abstract An original fabrication route of high-strength bulk Fe-5Ag and Fe-10Ag nanocomposites with enhanced degradation rate is reported. Near fully dense materials with fine nanostructures and uniform distribution of Ag nanoparticles were obtained employing high energy attrition milling of Fe-Ag2O powder blends followed by cold sintering – high pressure consolidation at ambient temperature that allowed the retention of the nanoscale structure. Annealing in hydrogen flow at 550 °C resulted in enhanced ductility without coarsening the nanostructure. The strength in compression of Fe5Ag and Fe10Ag nanocomposites was several-fold higher than the values reported for similar composites with mic…

Degradation of Diazinon based on photoelectrocatalytic technique using enhanced WO3 nanostructures: Mechanism and pathway

2021

[EN] In this work, a resistant and toxic pesticide called diazinon was degraded through the photoelectrocatalysis (PEC) technique using tungsten oxide (WO3) nanostructures, applying an external bias of 1VAg/AgCl and simulated solar illumination. For this, WO3 nanostructures have been synthesized using electrochemical anodization in 0.05 M hydrogen peroxide and 1.5 M of different acidic electrolytes: H2SO4, CH4O3S or HNO3. Morphology, composition and crystallinity of the samples were evaluated through Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM) and Raman Spectroscopy. Then, the photoelectrochemical properties of the samples were analyzed by Photo-Elect…

Subwavelength mapping of surface photonic states

2003

We show that the spectral tailoring of optical local density of states (LDOS) may be achieved by lithographically designed nanostructures and that the subwavelength mapping of the spectral variation of the optical LDOS is feasible by varying the driving frequency of the effective dipole used in an illumination mode scanning near-field optical microscope.

Smart High-κ Nanodielectrics Using Solid Supported Polyoxometalate-Rich Nanostructures

2011

Utilizing Langmuir-Blodgett deposition and scanning probe microscopy, we have investigated the extent to which cations alter the self-assembly processes of hybrid polyoxometalates (POMs) on surfaces. The well-defined 2D hexagonal nanostructures obtained were extensively characterized and their properties were studied, and this has revealed fascinating dielectric behavior and reversible capacitive properties. The nanostructures are extremely stable under ambient conditions, and yet exhibit fascinating self-patterning upon heating. These findings present POMs as effective smart nanodielectrics and open up a new field for future POM applications. (c) 2011 American Chemical Society.

ELECTRICAL-FIELD CONTROL OF MAGNETISM MEDIATED BY STRAIN IN Ni NANOSTRUCTURES FABRICATED ON PRE-POLED PMN–PT (011)

2013

We investigate the effects of piezoelectric-generated strain on the magnetization configuration of Ni nanostructures fabricated on pre-poled piezoelectric (011) [ Pb ( Mg 0.33 Nb 0.66) O 3]0.68–[ PbTiO 3]0.32 (PMN–PT) by high resolution X-ray microscopy. We observe a strong uniaxial anisotropy in the Ni nanostructures, due to the relaxation of the substrate following the deposition of the Ni . The anisotropy can be modified by the application of an electric field to the piezoelectric substrate (thus generating a piezoelectric strain in the system) through the magneto-elastic effect. By applying an electric field to the PMN–PT, the magnetization configuration in nanostructured Ni squares an…

Growth of gold tips onto hyperbranched CdTe nanostructures

2008

Multilayer modified NH<inf>4</inf>NO<inf>3</inf> granules with 3D nanoporous structure: Effect of the heat treatment regime o…

2017

The article is devoted to the investigation of the structure of macro- and mesopores on the surface and inside of modified NH4NO3 granules. The main quality indicators of modified NH4NO3 granules are presented and the relationship between the nanoporous structure of granules and the quality indicators is shown. Various thermodynamic conditions for obtaining a nanoporous structure of the surface and internal layers during the modification of granules are considered. The optimal regime for the uniformity of the temperature distribution in the vortex granulator is the regime of mixed motion of the drying agent. In this mode, mainly “modification” pores are formed, “mechanical” pores due to the…

Crystal growth of ZnO micro and nanostructures by PVT on c-sapphire and amorphous quartz substrates

2010

Abstract ZnO micro and nanostructures in the form of tripods, grains, arrows and wires have been grown at temperatures as low as 500–300  ∘ C by a vapour transport method without catalysis and using a well selected value of the carrier gas flow. A transition state between grains and nanowires is reported being characterized by arrow-like structures which are constituted by a pyramidal head and a tail that is growing from the basal plane of the head. In order to understand the effect of growth conditions on the morphology of micro and nanostructures, an analysis of temperature and species concentration conditions has been carried out. In addition two different kinds of substrates have been u…

Synthesis and physico-chemical characterization of gold nanoparticles softly coated by AOT

2006

Size-controlled gold nanoparticles/surfactant stable systems were prepared by the combined action of the solvated metal atom dispersion (SMAD) technique and confinement in anhydrous sodium bis(2-ethylhexyl)sulfosuccinate (AOT) micellar solution. From liquid samples, by evaporation of the organic solvent, solid gold nanoparticle-surfactant liquid crystals composites were obtained. Sample characterization was performed by X-ray diffraction (SAXS and WAXS), XPS spectroscopy and UV-vis-NIR spectroscopy. All experimental data consistently revealed the coexistence of two gold nanoparticle size populations: bigger nanoparticles (size 20-50 angstrom) and smaller ones (size of few angstrom). The two…