نتایج جستجو برای: the surface area decreases x
تعداد نتایج: 16289058 فیلتر نتایج به سال:
In the present investigation, γ-alumina nanoparticles with particle sizes less than 10 nm, high specific surface area (351 m2/g), high pore volumes and relatively narrow pore sizes distribution was prepared via sol-gel method in presence of aluminum isopropoxide as an aluminum precursor, distilled water, acetic acid as hydrolysis rate controller and tert-butanol as solvent. They had meso ...
sol-gel derived sulfur modified and pure zno nanorod were prepared using zinc chloride and thiocarbamide as raw materials. prepared nanorods were characterized by means of x-ray diffraction (xrd), thermogravimetry- differential scanning calorimetry (tg–dsc), uv- vis absorption spectroscopy, brunauer emmett teller (bet) specific surface area and barrett joyner halenda (bjh) pore size distributio...
Based on the {S+, I-} pathway, the concentration of surfactant and surface charge density of silanolate groups control the phase transition from lamellar, to hexagonal through cubic form. The high surface charge density of silanolate groups was observed for the lamellar phase. With decrease of molar concentration of surfactant on the gel, the yield of...
In the present investigation surface modification of silica nanoparticles by alumina was carried out by sol-gel process. Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) confirmed the synthesis of silica and the surface modification as alumina is anchored to silica surface. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigation...
In the present investigation surface modification of silica nanoparticles by alumina was carried out by sol-gel process. Fourier transform infrared (FTIR) and X-ray fluorescence (XRF) confirmed the synthesis of silica and the surface modification as alumina is anchored to silica surface. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigation...
today, scouring is one of the important topics in the river and coastal engineering so that the most destruction in the bridges is occurred due to this phenomenon. whereas the bridges are assumed as the most important connecting structures in the communications roads in the country and their importance is doubled while floodwater, thus exact design and maintenance thereof is very crucial. f...
there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...
abstract governing was disorganized for years, when mongols attached to iran and it caused to clearing way for interference of mongols princes. dispatching of holaku to the west culminated in establishing iilkhanan government. holakus activities in destruction of abbaasis government and activities which shows his staying in iran, made force oulus juji to comparison against iilkhanis gover...
Background: Multiple beams are generally used with an increased possibility that the beam axis intersects the treatment table. Treatment tabletops are commonly made of carbon fiber due to its high mechanical strength and rigidity, low specific density, extremely light and low radiation beam attenuation properties. Purpose of this paper is investigated the dose changes in the buildup region and ...
structural properties and chemical composition change the photocatalytic activity in tio2-sio2 nanopowder composite. the sio2-tio2 nanostructure is synthesized based on sol–gel method. the nanoparticles are characterized by x-ray fluorescents (xrf), x- ray diffraction (xrd), tunneling electron microscopy (tem), field emission scanning electron microscopy (fe-sem), uv-vis. spectrophotometer and ...
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