نتایج جستجو برای: the surface area decreases x
تعداد نتایج: 16289058 فیلتر نتایج به سال:
Nanocrystalline strontium hexaferrite (SrFe12O19) powders have been successfully synthesized using the facile Co-precipitation method. The ferrite precursors were achieved from mixtures of strontium and ferric chloride in an aqueous medium without any surfactant and soft template. The as-received powders were calcined at 800 and 1000 ˚C for 2 hours in air. The final powders were characterized b...
This work describes the optical and structure properties of nickel sulfide and cobalt sulfide nanoparticles in ZSM-5 zeolite. The samples were obtained by sulfidation of the Ni2+ and Co2+ ion-exchange ZSM-5 zeolites in a Na2S solution at room temperature. The optical properties of the samples were studied by UV-visible spectroscopy. Their crystalline structure and morphology were studied by X-r...
Nanostructured iron oxide powder that has been recovered from waste pickling liquor unit of steel industry was studied for oxidation catalytic applications. In this research, the powder was characterized by X-ray diffraction (XRD) and transition electron microscopy (TEM) for determination of phase structure, morphology and particle size. Furthermore, the specific surface area of the powder was ...
A facile and simple method was proposed to control the size and shape of the MgO nano structures with high surface area in the presence of efficient and cheap templates like PEG 200, PEG 600, PEG 4000 and sorbitol at low temperature within a little time. Nano rods and Nanoparticles have been achieved by applying these templates and altering other growth parameters. The products were charact...
CO2 reforming of methane (CRM) over unpromoted and potassium promoted Ni/Al2O3 catalysts was studied. The catalysts were prepared by impregnation method and characterized by X-ray diffraction (XRD), N2 adsorption (BET), temperature programmed reduction (TPR), temperature programmed oxidation (TPO) and scanning electron microscope (SEM) techniques. The obtained results showed that addition of K2...
in the area of vocabulary teaching and learning although much research has been done, only some of it has led to effective techniques of vocabulary teaching and many language learners still have problem learning vocabulary. the urge behind this study was to investigate three methods of teaching words. the first one was teaching words in context based on a traditional method of teaching that is,...
In this study, the composite material with composition of MgH2-5 wt% SiC has been prepared by co-milling of MgH2 with SiC powder. The effect of milling time and additive on MgH2 structure, i.e. crystallite size, lattice strain, particle size and specific surface area, and also hydrogen desorption properties of obtained composite was evaluated by thermal analyzer method and compared with pure un...
molecular dynamic simulation is a powerful method that monitors all variations in the atomic level in explicit solvent. by this method we can calculate many chemical and biochemical properties of large scale biological systems. in this work all-atom molecular dynamics simulation of polyalanine (pa) was investigated in the presence of 0.224, 0.448, 0.673, 0.897 and 1.122 m of guanidinium chlorid...
Ternary (%mol) (64SiO2-31CaO-5P2O5) system of sol-gel derived bioactive glass fibers was prepared by electrospinning method. X-ray Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and nitrogen adsorption test (BET) analyses were performed to investigate the phase and chemical group of the composition, morphology of the surface and specific surface area of the f...
In the current work, graphene oxide (GO) samples were prepared at room temperature from graphite flakes using a modified Hummer's method to produce metal-free electrocatalysts. The effect of the duration of the oxidation process on the structural, chemical and physical characteristics of the GO samples was evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ...
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