Synthesis and thermal behavior of nanoceramic material based on Bi13Fe5Ti6O39

The process of formation by the chemical coprecipitation method of nanoceramic material based on layered perovskite-like complex oxide Bi13Fe5Ti6O39 with the structure of the Aurivillius phase has been described. The temperatures of the onset of formation, the onset of decomposition, and activation of sintering, as well as the coefficient of linear thermal extension of the material, have been determined. Technological parameters for the synthesis of the material with a high yield of the target product and the ability to vary the crystallite size in the range of 70‒85 nm have been determined.

Structural evolution and synthesis mechanism of ytterbium disilicate powders prepared by cocurrent chemical coprecipitation method

Ytterbium disilicate powders were synthesized by cocurrent chemical coprecipitation method. The influence of Si/Yb molar ratio and calcination temperature on compositions and structures of Yb2Si2O7 products were investigated. The formation mechanism and thermal behavior of precursor as well as the phase evolution of Yb2Si2O7 were also discussed in depth. Results show that pure β-Yb2Si2O7 powders with nanoscale size can be obtained from the precursor with Si/Yb molar ratio of 1.1 after being calcinated at temperatures above 1200 ℃. The Yb2Si2O7 precursor is an amorphous polymer cross-linked with -[Si-O-Yb]- chain segments which are formed though Yb atoms embedding in the -[Si-O-Si]- network. After a continuous dihydroxylation and structural ordering, the amorphous precursor transformed to α-Yb2Si2O7 crystals by atomic rearrangement. Elevated calcination temperature can induce to the coordination structures and environment evolutions of structural units and then converted to stable (Si2O7) groups and (YbO6) polyhedrons, which results in the formation of β-Yb2Si2O7.

Synthesis of Zinc Sulfide Nanoparticles by Chemical Coprecipitation Method and its Bactericidal Activity Application

A particle of zinc sulfide (ZnS) was synthesized by the chemical coprecipitation method using zinc sulfate heptahydrate (ZnSO4), ammonium sulfate (NH4)2SO4 as a reactant, and thiourea as a stabilizer and capping agent. The optioned product characterized by electron dispersive X-ray spectroscopy that exhibits the presence of Zn and S elements. The average particle size of the ZnS nanoparticles determined using X-ray diffraction is about 4.9 nm. The ultraviolet–visible spectroscopy showed the blue shift in wavelength and the band gap was 4.33 eV, the surface morphology of the synthesized ZnS nanoparticles powder was studied by scan electron microscopy which was showed the irregular and some spherical shapes of ZnS in a nanosized range. The Fourier-transform infrared spectroscopy observed an absorption peck at 657.73 and 613.36 cm−1 that were assigned to the stretching mods of the Zn-S band. The different amounts of ZnS nanoparticle were applied as bactericidal against Staphylococcus aureus by disk diffusion method. It displayed activity against S. aureus bacteria, which was carried out in the absence of irradiation.

Effect of protamine on Fe3O4@CS@GFTN composite magnetic nanoparticles

Fe3O4@chitosan (CS)@Gefitinib (GFTN) core-shell structure composite magnetic nanoparticles (NPs) were prepared by chemical coprecipitation method in this study. In addition, protamine was doped in Fe3O4 cores to prepare Fe3O4@protamine@CS@GFTN core-shell structure composite NPs, in order to increase the loading of GFTN in composite NPs. They were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and spectrophotometer. The results show that the average size of Fe3O4@CS@GFTN and Fe3O4@protamine@CS@GFTN composite NPs is approximately 19 and 21[Formula: see text]nm, respectively. The saturation magnetizations of composite magnetic NPs and corresponding magnetic fluids are 57.20, 20.79, 59.58 and 19.75[Formula: see text]emu/g, respectively. The loading of GFTN in composite NPs was measured by a spectrophotometer to be about 13.5% and 27.6%, respectively. The addition of protamine increased the loading of GFTN two times, indicating that it will play an important role in the management of lung diseases.