نتایج جستجو برای: silica distribution
تعداد نتایج: 644141 فیلتر نتایج به سال:
اخیراً استفاده از معرف های تثبیت شده بر روی جامدات به دلیل سهولت جداسازی از محیط واکنش گسترش یافته است. در اینجا قصد داریم کاربرد h2so4-silica را به عنوان کاتالیزور اسیدی جامد که از سولفوریک اسید و سیلیکاژل تهیه می شود را برای تهیه نیترو فنول ها و کینولین ها گزارش کنیم. نیترو فنول ها از واکنش بین مشتق های فنول با استرانسیم نیترات در مجاورت h2so4-silica در دمای اتاق و شرایط بدون حلال تهیه شدند. م...
micro silica (ms) is an extremely fine, spherical powder that is used as an additive for improving concrete performance. it is obtained as a by product of silicon metal and ferrosilicon alloy production. due to its pozzolanic nature, micro silica can be used to enhance the qualities of both fresh and hardened concrete. addition of micro silica into the concrete as a cement replacement, dec...
One way of thermal stability methods and ablation improving for polyurethane elastomers to solid propellant rocket insulation, is using of fillers with high ablation property such as silica particles. In this research, first polyurethane-silica composites (16, 25 and 38% by weight) and polyurethane-silica nanocomposites (5, 10, 16 and 25% by weight) were prepared and then interaction, morpholog...
PURPOSE The effects of particle size on the tissue distribution and excretion kinetics of silica nanoparticles and their biological fates were investigated following a single oral administration to male and female rats. METHODS Silica nanoparticles of two different sizes (20 nm and 100 nm) were orally administered to male and female rats, respectively. Tissue distribution kinetics, excretion ...
the silica supported platinum nanoparticles was synthesized by using the sol-gel method. the possibility of using diamminedinitro platinum (ii) as pt precursor and effect of metal precursor concentration on the final pt nanoparticle size was investigated. a stable silica sol was prepared via hydrolysis of tetraethyl orthosilicate (teos) as a metal alcoxide and condensation reaction. subsequentl...
A three-dimensional micromechanical finite element model is developed to study the viscoelastic behavior of the silica nanoparticle/polyimide nanocomposites. The representative volume element (RVE) of the model consists of three phases including silica nanoparticle, polyimide matrix and interphase which surrounds the nanoparticle. The interphase region is created due to the interaction between ...
in this work, sio2 –zro2 mixed oxides was prepared by the polymeric sol–gel route. the characterization of pore structure, which determines the permeation process of membrane, is of great importance. so far, most investigations have focused on such pore structure as specific surface area and pore size distribution, but the surface fractal, the important parameter reflecting the roughness of por...
We report the optoelectronic device properties of individual Au-silica hybrid nanowires prepared by microwave plasma enhanced chemical vapor deposition. Due to the surface plasmon resonance (SPR) effect the photo-responsivity peak strongly depends on the shape of the embedded gold nanostructures in the silica nanowire in which the shape can be modified by controlling the growth time of Au-silic...
We describe the synthesis of magnetic and fluorescent silica microspheres fabricated by incorporating maghemite (gamma-Fe2O3) nanoparticles (MPs) and CdSe/CdZnS core/shell quantum dots (QDs) into a silica shell around preformed silica microspheres. The resultant approximately 500 nm microspheres have a narrow size distribution and show uniform incorporation of QDs and MPs into the shell. We hav...
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