various concentrations of copper were embedded into silica matrix to xerogel forms using copper source cu(no3)2∙3h2o. the xerogel samples were prepared by hydrolysis and condensation of tetraethyl ortho-silicate (teos) with determination of new molar ratio of the components by the sol-gel method. after ambient drying, the xerogel samples were heated from 60 to 1000˚c at a slow heating rate (50°...

the kalut-e-ashrafa area is located in the north-east of ardakan area in central iran, yazd province. this area promises copper mineralization. the most of the minerals in this study area are silica-rich veins and veinlets. therefore, in order to identify geological formations with silica zones and to determine potential mineralization areas, aster images and remote sensing methods were used. a...

A simple donor-acceptor linked dyad, 9-mesityl-10-methylacridinium ion (Acr(+)-Mes) was incorporated into nanosized mesoporous silica-alumina to form a composite, which in acetonitrile is highly dispersed. In this medium, upon visible light irradiation, the formation of an extremely long-lived electron-transfer state (Acr(•)-Mes(•+)) was confirmed by EPR and laser flash photolysis spectroscopic...

Hollow silica-copper-carbon (H-SCC) nanocomposites are first synthesized using copper metal-organic frameworks as skeletons to form Cu-MOF@SiO(2) and then subjected to heat treatment. In the composites, the hollow structure and the void space from the collapse of the MOF skeleton can accommodate the huge volume change, buffer the mechanical stress caused by lithium ion insertion/extraction and ...

this paper investigates axial compression process of multi-layered tubes with circular cross-section under the axial loading in the quasi-static condition using experimental method. some specimens are prepared in seven different groups, namely; empty carbon/epoxy composite tubes, solid carbon/epoxy composite rods, empty copper tubes, composite tubes with silicon sealant filler, concentrically s...

Highly ordered aluminum-containing mesoporous silica (Al-MCM-41) was prepared using attapulgite clay mineral as a Si and Al source. Mesoporous complexes embedded with CuO nanoparticles were subsequently prepared using various copper sources and different copper loadings in a direct synthetic route. The resulting CuO/Al-MCM-41 composite possessed p6mm hexagonally symmetry, well-developed mesopor...

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...

This paper investigates axial compression process of multi-layered tubes with circular cross-section under the axial loading in the quasi-static condition using experimental method. Some specimens are prepared in seven different groups, namely; empty carbon/epoxy composite tubes, solid carbon/epoxy composite rods, empty copper tubes, composite tubes with silicon sealant filler, concentrically s...

various concentrations of copper are embedded into silica matrix to xerogel form using copper source - cu(no3)2∙3h2o. the xerogel samples are prepared by hydrolysis and condensation of tetraethyl orthosilicate (teos) by the sol-gel method  and with determination of new molar ratio of components h2o/teos to be 6.2. in this investigation, the necessary amount of trihydrated copper nitrate is adde...