Search results for " Nanoparticle"

Magnetic nanoparticles between electrodes of tunnel junction: anomalous tunnel conductance

2002

Abstract Magnetic particles of microscopic size can be created in the process of Ni, Fe and Co mechanically controllable break junctions fabrication and trapped between the electrodes by magnetic dipole forces. Tunneling between the protruding nanoparticle and the sample electrode shows clear distinctions from the usual junctions: heavy deviation of the current–distance I(z) dependence from the expected exponential behavior at electrode separations z below 4.0– 4.5 A and on numerous occasions a sudden jump-like decrease of the tunnel current at z≈1.5– 2.0 A . Possible mechanisms behind observed anomalies including the short-range magnetic exchange coupling are discussed.

Coupling colloidal chemistry with coordination chemistry: Design of hybrid nanomaterials by the assembly of plasmonic nanoparticles and functional co…

2021

Nanotechnology involves the design, characterization, production and application of structures, devices and systems by the control of the shape and size at the nanometer scale involving different fields. In the last decade, nanotechnology development has boosted the interest in hybrid nanomaterials. These materials are a complimenting combination of two (or more) nanoparticles (NPs) with enhanced performance characteristics that offer exciting opportunities. It allows the possibility of integrating materials with different physical and chemical properties to widen the range of practical applications. In this context, Au NPs have recently attracted a lot of attention due to the great opportu…

Exploring the self-assembly of resorcinarenes : from molecular level interactions to mesoscopic structures

2012

A new efficient, highly dispersed, Pd nanoparticulate silica supported catalyst synthesized from an organometallic precursor. Study of the homogeneou…

2018

[EN] A new Pd(0) catalyst supported on silica UVM-7 has been synthesized from the organometallic [Pd-2(mu-(C6H4) Pp(2))(2)(CH3CN)(4)](BF4)(2) precursor, characterized by the high dispersion, activity, and small size of the palladium nanoclusters fixed on the silica surface. The catalyst was tested for the Suzuki-Miyaura (SM) reaction of different 4-substitutedphenyl halides with phenylboronic acid. The kinetic study concurs with most of the catalytic action was carried out by Pd species originated by the partial solubilization of Pd immobilized on mesoporous silica. The Schmidt's analysis of differential selectivity (SADS) in several competitive SM reactions, together the STEM-HAADF and HRT…

Mechanical and dentin bond strength properties of the nanosilver enriched glass ionomer cement

2019

Background The aim of this study was to investigate the mechanical properties and dentin microshear bond strength of a conventional glass ionomer cement (GIC) compared to GIC supplemented with silver nanoparticles (SNPs) at 0.1% and 0.2% (w/w). Material and Methods SNPs were incorporated into a conventional GIC at 0.1% and 0.2% (w/w). The unmodified GIC was used as the control group. Compressive strength, flexural strength, and micro-shear bond strength (µSBS) to dentin were evaluated using a universal testing machine. Surface microhardness was determined using a Vickers microhardness tester. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test. Results GICs co…

Influence of artificial aging and ZrO2 nanoparticle-reinforced repair resin on the denture repair strength

2019

Background The purpose of this study was to evaluate the effect of aging process on the tensile strength (TS) of repaired acrylic denture base using ZrO2 nanoparticles (nano-ZrO2)-reinforced autopolymerized resin. Material and Methods A total of 240 heat-polymerized acrylic resin specimens (n=10) were prepared and sectioned creating 2 mm-repair-gap. Autopolymerized acrylic resin, pure and modified with 2.5, 5, and 7.5wt% nano-ZrO2 were used for specimens repair. TS of repaired specimens were measured using the universal testing machine after water immersion at 37oC for 2, 7 and 30 days. At each time interval, half the immersed specimens underwent thermo-cycling aging process (5000 cycles at…

Electronic and optical properties of CeO 2 from first principles calculations

2016

International audience; First-principles calculations of the electronic structure of CeO2 nanoparticles (NPs) were performed to investigate published experimental data obtained by different spectroscopies. The main features of the valence and conduction bands have been analyzed from the total and partial density of states. Several functionals were applied to interpret and quantify the optical properties, including the dielectric function, extinction coefficient and refractive index. It is found that the on-site hybrid functional B3PW91 modelled most suitably the band gap region of CeO2 NPs and consequently gave a more accurate band gap value. It also agreed very well with the experimental v…

Solid Lipid Nanoparticles Containing Vancomycin

2007

Staphylococci coagulase-negative and Staphylococcus aureus are the most common cause of nosocomial infections and can induce a wide spectrum of diseases associated with remarkable morbidity and mortality. Biofilms of staphylococci are intrinsically resistant to conventional antibiotics and, being commonly associated with implanted medical device, such as catheters and vascular grafts, have the potential to cause blood-stream infections. In recent years increasing attention has been addressed to Solid Lipid Nanoparticles (SLNs), thanks to their biodegradability and ability to entrap a variety of biologically active compounds, in the area of modified drug delivery technology in the attempt to…

Resist-based silver nanocomposites synthesized by lithographic methods

2010

In this work, the formation of silver metal nanoparticles inside a negative-tone resist based on poly(vinyl alcohol) is achieved by electron beam lithography. The chemistry of this sensitive resist allows the production of nanoparticles as well as the polymer crosslinking by the electron radiation. Due to the presence of the silver nanoparticles, the final composite exhibits a plasmonic behavior, which was characterized by measuring the absorbance. The lithographic properties of the resist have been characterized. The technique has also been exported to UV lithography, where silver nanoparticles are obtained inside the polymeric patterns after optical lithography.

High-resolution electron-beam patternable nanocomposite containing metal nanoparticles for plasmonics

2008

Polymer nanocomposites containing noble metal nanoparticles are promising materials for plasmonic applications. In this paper, we report on a high-resolution negative-tone nanocomposite resist based on poly(vinyl alcohol) where silver nanoparticles and nanopatterns are simultaneously generated by electron-beam lithography. Our results indicate nanostructures with a relatively high concentration of nanoparticles and, consequently, an electromagnetic coupling among the nanoparticles. Therefore, the patternable nanocomposite described in this work may be a suitable material for future plasmonic circuitry.