نتایج جستجو برای: teos
تعداد نتایج: 740 فیلتر نتایج به سال:
Palladium nanoparticles were supported on a fluorous organic-inorganic hybrid material prepared by the sol-gel process without TEOS. Recycling studies on the Heck coupling reaction have shown that the catalyst can be readily recovered and reused.
Ordered mesoporous silicas SBA-15 with high loadings of pendant vinyl groups have been synthesized via co-condensation of tetraethoxysilane (TEOS) and triethoxyvinylsilane (TEVS) templated with a triblock copolymer.
in this research controlled coating of magnetite (fe3o4) nanoparticles with sio2 was investigated. the fe3o4 nanoparticles were synthesized via chemical co-precipitation and then coated by silica according to stober method. effects of tetra ethyl ortho silicate (teos) concentration and ethanol to teos on the coating thickness were investigated. x-ray powder diffraction, fourier transform infrar...
Samples of a commercial glass fiber FM® (Fiber Max) were used to test the efficacy of a chemical sol-gel surface treatment to enhance their bioactivity. After treatment with tetraethoxysilane (TEOS), individual fiber samples were soaked into a simulated body fluid (SBF) solution, from which they were removed at intervals of 5 and 10 days. Micrographs obtained by scanning electron microscopy (SE...
Perylenediimide functionalized bridged siloxane nanoparticles were prepared by direct hydrolysis and condensation of a perylenediimide silane precursor in the presence of a catalytic amount of tetraethoxysilane (TEOS). The sizes of the particles were controlled by adjusting organotrialkoxysilane, base, and TEOS concentrations. Using this modified Stöber method, we were able to incorporate a hig...
classical xerogels are robust, inexpensive and nontoxic materials with low-ordered nanoporous structures. in water streams where the ph is higher than the point of zero charge, the surface of classical xerogels such as tetraethoxy orthosilan (teos) xerogel is negatively charged. it was assumed that a xerogel can work as a strong adsorbent for metal ions without further modification. therefore, ...
An efficient and reusable adsorbent, namely 3-mercaptopropionic acid modified tetraethyl orthosilicate (TEOS) grafted MnFe2O4 nanoparticles (MPA-TEOS-MnFe2O4 NPs) was synthesized and used for the extraction and preconcentration of trace amount of Al (III) and Cr (III) ions in water samples. MnFe2O4 NPs were prepared by chemical c...
هدف از انجام این پژوهش سنتز سیلیکا اروژل با فرایند سل-ژل با استفاده از پیش ماده آلی( TEOS)، آب و ایزو پروپیل الکل (IPA) و حلال n-هپتان و محلولهای کاتالیست HCl و NH4F با تغییر 4 پارامتر نسبتهای مولی TMCS/TEOS, Total H2O/TEOS, IPA/TEOS , و CNH4F و اندازه گیری دانسیته و تعیین درصد تخلخل و ضریب شکست نور بوده است. پیرسازی درون ایزوپروپیل الکل، تعویض حلال با n- هپتان و اصلاح سطح درون محلولهای 11%...
Abstract. The international Thermodynamic Equation of Seawater 2010 (TEOS-10) defined the enthalpy and entropy seawater, thus enabling global ocean heat content to be calculated as volume integral product in situ density, ?, potential enthalpy, h0 (with reference sea pressure 0 dbar). In terms Conservative Temperature, ?, is ?cp0?, where cp0 a constant “isobaric capacity”. However, many models ...
Ester-silica nanoparticles (NPs) were prepared using a facile two-surfactant synthesis route in neutral medium involving silica (tetraethyl orthosilicate, TEOS) and organosilica (3-(trimethoxysilyl)propyl 5-(trimethoxysilyl)pentanoate, PMe) precursors. The ester hydrolysis generates carboxylic acid groups, which confer strongly negative zeta potential to the NPs at pH. extent of during was quan...
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