نتایج جستجو برای: crystallite
تعداد نتایج: 2291 فیلتر نتایج به سال:
in this work, ce0.75gd0.1ca0.15o1.8 nanopowders are successfully synthesized by a glycine-nitrate combustionprocess under the microwave irradiation. then calcination was carried out at 700 °c. calcined powdersidentified by room temperature x-ray diffraction were single phase and had a crystallite size between 16 to 24nm (based on schererr formula). scanning electron microscopy (sem) was employe...
the synthesis of nano- structured cobalt through a controlled chemical process followed by heat treating at various temperatures is studied. the product is characterized by icp, xrd, fesem , and tem, indicating that the as- synthesized particles have an amorphous structure with 1.76 for co/b ratio, an average size of 50 nm. the transformation of intermediate phases into single phase nano- cryst...
1. Introduction Measuring diffusion in zeolites is a long-lasting challenge. For more than 70 years many efforts have been made to determine the diffusion coefficient of host molecules in the porous framework of zeolites [1]. Actually the different techniques, which were applied, observed different processes and provided dissenting diffusion coefficients. Precisely, there are methods observing ...
In this paper we present measurements of the crystallization kinetics of binary mixtures of two different sized hard sphere particles. The growth of the Bragg reflections over time were analyzed to yield the crystallite scattering vector, the total amount of crystal, and the average linear crystal size. It was observed that a particle size distribution skewed to higher sized particles has a les...
Materials that consist of a random microstructure can affect ultrasonic measurements--reducing signal strength, increasing noise, and reducing measurement accuracy--through scattering and aberration of the acoustic field. To account for these adverse effects a phase screen model, alongside the stochastic wave equation, has been developed. This approach allows the field and study aberrations to ...
In this paper, we report the comparison between TiO2 nanoparticles prepared via two different routes; i) via sol-gel route and ii) by hydrothermal method. It was found that when prepared under the same ambient conditions viz temperature, pressure etc. and keeping all the parameters same viz precursors, mole ratio, solvent etc; the nanoparticles prepared via sol-gel route were highly crystalline...
X-ray powder diffraction of red kangaroo (Macropus rufus) dental enamel, with a relative density greater than 2.60, showed a longer a-axis length of the apatite unit cell, a = 9.462 A, a shorter c-axis length, c = 6.877 A, and a smaller crystallite size, ca. 185 A, than those of human dental enamel. The a-axis of red kangaroo dental enamel was one of the longest among the values reported previo...
Cobalt-doped iron oxide nanoparticles were prepared by solution combustion technique. The structural and magnetic properties of the prepared samples were also investigated. The average crystallite size of cobalt ferrite (CoFe2O4) magnetic nanoparticle was calculated using Scherrer equation, and it was found to be 16±5 nm. The particle size was measured by transmission electron microscope. This ...
We explore the effects of crystallite size (L(a)) on the linear and non-linear optical properties of chemical vapor deposition grown polycrystalline graphene. The π-plasmon resonance present at ∼4.75 eV (∼260 nm) in the optical absorption spectrum of graphene follows the empirical relationship λ(π) = 250.5 nm + 89.5 nm(2)/L(a), where λ(π) represents the π-plasmon wavelength. Furthermore, our Z-...
Response Surface Methodology Study on Magnetite Nanoparticle Formation under Hydrothermal Conditions
In a hydrothermal preparation of crystalline magnetite (Fe3O4) nanoparticles, the influence of the experimental parameters (initial molar ratio of ferrous/ferric ions, initial concentration of ferrous ions, and heating time), and their interactions, on the particle formation was studied using response surface methodology (RSM), based on a statistical design of experiments (DOE). As indices indi...
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