Sharif Digital Repository

In recent years magnesium nanoparticles due to their noticeable differences from bulk and their wide applications in various branches including the ability to absorb hydrogen, application in batteries, activation of propellant, different applications in biochemistry and strengthening secondary phase in composites, are well under investigation. The objective of this study is to find an easy, economical and high purity method to obtain magnesium nanoparticles and to introduce an innovative approach of magnesium nanoparticles synthesis in an industrial scale. To achieve this goal, milling process is applied. Micron-sized magnesium powders with different amounts of sodium chloride salt powders... 

It is necessary to monitor pollutants in aquatic samples, because many of these compounds can pose threats to human health and the ecosystem. Separation technology based on magnetic materials has received considerable attention in recent years. The magnetic extraction method is not only convenient, economical and highly efficient, but it also overcomes problems with conventional solid-phase extraction. In order to remove anionic dyes from single and ternary systems, zinc ferrite nanoparticle was synthesized using co-precipitation method and its surface was modified by Cetyltrimethyl ammonium bromide (CTAB) cationic surfactant. Surface characteristics of ZFN-CTAB was studied using Fourier... 

Sialons are materials which crystallize in four elements system (Si-Al-O-N). These materials have been widely observed by researchers because of their suitable properties like: high toughness and strength in high temperatures, high resistance to corrosion and stability in thermal shock. Because of these properties,Sialons are anti erosion materials. In this research, by controling the situations, mullite has been synthesized by sol-gel procedure. Then the powder has been ground by ballmill for 12 hours and by spex for 30 minutes. Then the produced powder was mixed with distinct amount of graphite and nano silica and was nitrided in the furnace at 1500 ̊C and was heated for 5 hours. Also... 

Graphene nanogrids fabricated by graphene nanoribbons obtained through oxidative unzipping of multi-walled carbon nanotubes, used as two-dimensional selective templates for accelerated differentiation of human mesenchymal stem cells (hMSCs), isolated from umbilical cord blood, into osteogenic lineage. The biocompatible and hydrophilic graphene nanogrids showed high actin cytoskeleton proliferations that coinciding with patterns of the nanogrids. The amounts of proliferations found are slightly better than proliferation on hydrophilic graphene oxide (GO) sheets, and significantly higher than non-uniform proliferations on hydrophobic reduced graphene oxide (rGO) sheets and polydimethylsiloxane... 

One atom thick layer of pure carbon in bonded and hexagonal lattice is named graphene. graphene has unique mechanical, optical, thermal and electrical properties and because of these properties has grabbed attention. graphene has been made from high pure graphite by different methods such as CVD(chemical vapor deposition) , chemical exfoliation , micromechanical cleavage and colloidal suspension. through these methods, green methods for synthesis of graphene, using eco-friendly reductants during synthesis of graphene instead of hydrazine and recently using waste(not graphite) are attractive for synthesis of graphene. Following this idea , a group has produced graphene from wastes such as... 

Graphene is a two dimensional lattice which is created from carbon atoms. Having special feature, it has such various medical usage, for example in diagnosing and treating cancer. Adding a particular factor to graphene could improve their efficiency. In comparis on with graphene itself, graphene oxide and reduced graphene oxide are much more successful in diagnosing and treating than others because of their higher hygroscopic. Recent studies state that hydrogenized combinations including hydrogenized graphene show desired results. Due to its higher hygroscopic and the possibility of adherence to the cells, hydrogenized graphene could be very effective in diagnosing and treating the sarcomas.... 

The Cu2ZnSnS4 (CZTS) quaternary compound, with suitable optical and electrical properties, is one of the most interesting materials for absorber layer of thin film solar cell. Since all constituents of CZTS, are abundant in earth’s crust and non-toxic, it is a proper replacement for the materials like CdTe and CuInSe2. The CZTS pellet was synthesized by the solid-state reaction and deposited on soda lime glass substrates by pulsed laser deposition (PLD) method. PLD technique has the advantages of offering stoichiometric preservation during the materials transformation from target to substrate and good crystallinity due to the highly energetic species. CZTS has was deposited in order to... 

The purpose of this research is the synthesis of nanoparticles using micro fluid glass.The microfluidic glassy building is studied. Glass microfluidic microchannels making hydrophobic the continuing experiments carried out so that the water droplets in the organic phase and at the end of nanoparticles should be synthesized. Tests hydrophobic microchannels and water droplets in the organic phase was formed. In order to ensure an escape water contact angle and FTIR micro-channel test is taken and to avoid the droplets merged with each of surfactant SDS was used. In the end, DLS and FESEM nanoparticles synthesized using the tests have been evaluated and the concentrations of reactants and flow... 

Green chemistry seeks to reduce or eliminate the use of hazardous substances in the chemical industry through the development of new products and processes .The replacement of harmful, widely used solvents and reagents is a key part of this approach. Supercritical fluid such as CO2 or water are good solvent for replaceement Exchange reactions involving the displacement of hydrogen bonded to carbon by deuterium are of interest in a broad variety of disciplines, such as the preparative chemistry of isotopically labeled materials, fundamental studies of carbonehydrogen bond activation processes, and studies of the nature of catalysts. The low cost of water and its environmental friendliness... 

Today organometallic perovskites are very important in fabrication of solar cells. This materials have advantages like high mobility of charge carriers, changing in range of light aborption with changing in structures atoms, having longer charge carrier diffusion lengths than other materials, high stability and efficiency, Low-cost fabrication process, having capability of studying and processing in low temperatures and having flexibility because of Weak chemical bond in perovskite structure. Due to the low stability and rapid decomposition of this material with the presence of light and moisture, in this study has tried to use PbS quantum dots which is used in sensitive dye solar cells as... 

Octahedral crystals of Fe-Metal-organic frameworks like Fe-MIL-101, which is the most stable and active metal-organic frameworks; in combination with graphitic carbon nitride nanosheets could significantly enhance the photocatalytic activity of g-C3N4 for inorganic dye degradation under the irradiation of visible light application. This appropriate cocatalyst modifies the performance of semiconductor via suppressing the recombination of photo-induced carriers and since the synthesized composite prepared by in-situ procedure possesses close contact between each other, the migration of electrons in the photocatalytic reaction will be continued, so the degradation process via the active species... 

To produce polyurea, a secondary or higher amine must be combined with a diisocyanate. For this purpose, we first combined diethylenetriamine, and hexamethylene diisocyanate, which did not have good mechanical properties due to the aliphatic nature of the molecules. Then, instead of hexamethylene diisocyanate, we used MDI, which was mixed using a mechanical mixer but became a paste that was not suitable for coating applications. To reduce the viscosity of MDI, propylene carbonate was added to improve mixing, but the gel time also increased. Because the solvent was non-polar and the amine was polar, it was decided to add the solvent, amine, and polyvinyl alcohol as surfactants to allow faster... 

A decade after discovery of graphene, the unique properties and characteristics of two-dimensional materials, particularly an emerging family of carbides and nitrides (MXenes), have attracted the attention of researchers. MXenes are two-dimensional structures of two or more layers of transition metals, with interstitial carbon and/or nitrogen atoms, with exceptional properties such as high specific surface area, excellent elastic modulus, metallic conductivity, and various termination groups. These properties can be altered by various factors, including chemical composition and synthesis processes, and any changes in these factors significantly affect the properties of MXene sheets. In this...