silica exists in rice husk, an agriculture waste, as a naturally occurring phase. in first step, acidic pre-treatment and calcination of the rice husk were performed to obtain nano-silica, in which various sizes of the nano-silica, totally with sizes under 80 nm, were achieved. second, to reduce nano-silica to elemental si and subsequently formation of the composite, mg used as the reducing age...

in this paper, the morphology, roughness and nano structural properties of sio2/poly vinyl pyrrolidone  synthesized with sol gel method,  characterized by using scanning electron microscopy, atomic force microscopy and gps132a techniques.the main material taken from oxide silicon with weight percentage of 20, 40, 60, 80 and from poly vinyl pyrrolidone with percentages of 80, 60, 40, 20 is synth...

background and aim: this study investigated the reinforcing effect of silica nanoparticles when incorporated into the matrix phase of an experimental dental fiber reinforced composites (frc) through the evaluation of the flexural properties of the composites. materials and methods: in this experimental study frc samples were divided into two main groups (containing two or three bundles) either ...

in this experimental work, by using the method of plasma-chemical etching, we have dealtwith the causes of the creation of a distorted layer on the surface of silicon wafers during mechanicalmachining processes, in addition, the elucidation of connections between the structure of this layer andcharacteristic parameters of the mechanical strength of these wafers have been studied. experimentalre...

background peripheral nerve repair is often complicated by fibroblastic scar formation, nerve dysfunction, and traumatic neuroma formation. use of silicone may improve outcomes of these repairs. in this study, we tried to evaluate effectiveness of silicone gel on rats’ sciatic nerve repair, axon regeneration and scar formation around and in the nervous tissues. methods this experimental study w...

in this study, the radial distribution and gravimetric storage capacities of hydrogen on coronene (c24h12) and its si substituted forms, c24h12, c24-nsinh12 (n= 4-24), have been investigated at 298 k and 0.1 mpa (standard situation) using (n,v,t) monte carlo simulation by lennard-jones (lj) 12-6 potential. the results show that the increase of number of silicon substitution doesn’t have any eff...

wetability of biocompatible polymers can be improved by plasma surface modification. the purpose of this study was to surface modify an experimental poly (dimethylsiloxane) rubber (pdms) material in order to improve its wetability and biocompatibility. surface properties of the pdms were characterized using contact angles measurement for wetability analysis. samples of experimental silicone rub...

a r t i c l e i n f o In this work we demonstrate that the room-temperature deposition of the organic molecule 9,10-phenanthrenequinone (PQ) reduces the surface defect density of the silicon (100) surface by chemically bonding to the surface dangling bonds. Using various spectroscopic measurements we have investigated the electronic structure and band alignment properties of the PQ/Si interface...

Metal-assisted chemical etching of silicon is an electroless method that can produce porous silicon by immersing metal-modified silicon in a hydrofluoric acid solution without electrical bias. We have been studying the metal-assisted hydrofluoric acid etching of silicon using dissolved oxygen as an oxidizing agent. Three major factors control the etching reaction and the porous silicon structur...

Traditional fibre-optic drawing involves a thermally mediated geometric scaling where both the fibre materials and their relative positions are identical to those found in the fibre preform. To date, all thermally drawn fibres are limited to the preform composition and geometry. Here, we fabricate a metre-long crystalline silicon-core, silica-cladded fibre from a preform that does not contain a...