Sharif Digital Repository

We studied the effects of the surrounding liquid environment on the size and optical properties of silver nanoparticles prepared by laser ablation by a pulsed Nd:YAG laser operated at 1.064 nm. The silver targets used were kept in acetone, water and ethanol. TEM observations and optical extinction were employed for characterization of particle size, shape and optical properties, respectively. Nano silver in acetone showed a narrow size distribution with a mean size of 5 nm and the colloidal solution was stable. In deionised water a rather narrow size distribution with a mean size of 13 nm was observed and nanoparticles were precipitated slowly after about two weeks. In ethanol, a broadening... 

The electrochemical behavior of captopril at the surface of a carbon-paste electrode (CPE) modified with cobalt-5-nitrolsalophen (CoNSal) is described. The prepared electrode shows an excellent electrocatalytic activity toward the oxidation of captopril, which is leading to marked lowering in the anodic overpotential and considerable improvement of sensitivity (anodic current). Whereas at the surface of unmodified electrode an electrochemical activity for captopril cannot be observed, a very sharp anodic wave with an anodic peak potential about 650 mV (versus Ag/AgCl) is obtained using the prepared modified electrode. This catalytic wave is assigned to mediating of Co(III)/Co(II) redox... 

Nanopowders are powders with particle size less than 100 nanometer. The applications of nanopowders are in the production and processing of nanocomposites, microelectronic, industrial cathalists, coating, sintering at low temperature, lubricants, propellants, purification of aqiuos solutions, biomaterials and filtration. In this work, a reactor for production of nanopowder using IGC method was designed and manufactured. By changing the production parameters such as chamber temperature and pressure, evaporation rate, precursor and evaporation time, silver powders were produced. The characteristics of the produced powders were studied using EDX, SEM and TEM techniques. The results showed that... 

A standard simulating technique test was investigated to assess the atmospheric corrosion behavior of silver coating. The rates of formation of corrosion products were measured in the simulating atmospheres of 100% humidity containing SO 2,H 2S and a complex atmosphere consist of SO 2,H 2S and NO 2 gases ,based on the mass increase method. The concentrations of corrosive gases were chosen according to real world conditions. XRD, SEM and EDS were used to examine the morphology and to determine the composition of the corrosion products under different experimental conditions. Results revealed the formation of Ag 2SO 4 and Ag 2S on the silver coating surfaces in the SO 2 and H 2S containing...