نتایج جستجو برای: crystallite refinement

تعداد نتایج: 35490  

2017
Moges Tsega F.B. Dejene

Titanium dioxide (TiO2) nanoparticles were prepared by the sol-gel method at different pH values (3.2-6.8) with a hydrochloric acid (HCl) solution. Raw samples were calcined at 500 °C for 2 h. The effects of pH on the structural, morphological and optical properties of TiO2 nanoparticles were investigated. At pH 4.4-6.8, only the anatase phase of TiO2 was observed. Under strong acidic condition...

Journal: :journal of nanostructures 2012
r. raeisi shahraki m. ebrahimi

superparamagnetic single phase zinc ferrite nanoparticles have been prepared by coprecipitation method at 20 °c without any subsequent calcination. the composition, crystallite size, microstructure and magnetic properties of the prepared nanoparticles were investigated using x-ray diffraction (xrd), field emission scanning electron microscope (fesem), transmission electron microscope (tem), fou...

Journal: :journal of the iranian chemical research 0
ali ainirad department of chemistry, university of science and technology of iran, tehran, iran

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...

Journal: :journal of nanostructures 2012
a. ataie h. sabarou

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...

2005
Hannes Pahlke Burkhard Geil Danuta Kruk Franz Fujara

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 ...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2005
S Martin G Bryant W van Megen

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...

Journal: :The Journal of the Acoustical Society of America 2007
J A Hernández M Clark S D Sharples M G Somekh V H Lopez

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 ...

2012
R. Vijayalakshmi

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...

Journal: :The Journal of Nihon University School of Dentistry 1990
T Sakae M Sekikawa

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...

Journal: :international journal of iron & steel society of iran 2015
m. atapour m. m dana f. ashrafizadeh

aisi 304l austenitic stainless steel with different grain sizes of 0.5 -12 μm was obtained through the martensiticprocess. corrosion behavior of different samples was investigated in a 0.5m hcl solution using open circuitpotential, potentiodynamic polarization and electrochemical impedance spectroscopy tests. also, the correlationbetween the grain size and pitting corrosion resistance was asses...

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