Sharif Digital Repository

Photodynamic therapy that has developed over last century, now has become more widely used medical tool for the treatment of various diseases such as cancer. This technique involves delivery of photosensitizing drugs, irradiation of light and motivation of drugs. The limitation of light penetration in body tissue, may resolve by application of upconversion nanoparticles. Upconverting nanoparticles could help treatment of cancer tumors in deep or critical points of body by converting high penetrating Near-Infrared emissions to higher energy visible emissions.In this research Er3+-Yb3+ Co-doped titanium dioxide upconversion nanoparticles prepared by Sol-gel method. The phase structure and... 

Photodynamic therapy that has been developed over last century, now has become more widely used medical tool for the treatment of various diseases such as cancer. This technique involves delivery of photosensitizing drugs, irradiation of light and motivation of drugs. The limitation of light penetration in body tissue, may resolve by application of upconversion nanoparticles. Upconverting nanoparticles could help treatment of cancer tumors in deep or critical points of body by converting high penetrating Near-Infrared emissions to higher energy visible emissions. In the present work, rare earth elements doped TiO2 nanoparticles are synthesized. The photodynamic properties of rare earth... 

Nowadays, apatite mineral is one of the most sought for the recovery of rare earth elements. This mineral is also the main source of phosphoric acid production. To achieve this end, apatite has to react with sulfuric acid to give phosphoric acid. This process is called the wet process. During the wet process, more rare elements enter the remaining solids called phosphogypsum (PG). For the dissolution of rare elements, PG, which is the same as chalk, can be leach with an acidic solution. In this project, the phosphate concentrate from Chadormalu iron ore waste after characteristics diagnosis is digested in concentrated sulfuric acid at temperatures below 100 ° C, and then hydration is... 

The term “Rare Earth”, represents 17 metalic elements such as Sc, Y and Lanthanides wich have similar chemical properties. Lanthanides are a group of elements with atomic numbers of 57 to 71 that all of them exept Pm are present in nature. Rare earth elements are never concentrated in a special mine rock, but they could be found in various rocks and at very low concentrations. In the present study, apatite concentrate of Chadormalu was used for leaching and solvent extraction of Cerium, Lanthanum and Neodymium. After leaching step, its optimum conditions were found as follow: 30% nitric acid, 10 mins time and 10% for solid to liquid ratio. After finding optimum conditions, sufficient leach... 

Vehicle exhaust gas catalysts play a significant role in air pollution control. In order to solve the problems of cold start and limited supply of precious metals, new studies have focused on the development of three-way catalysts for gasoline vehicles with small amounts of precious metals and increase thermal stability. Different metal ions, especially rare earth metals, due to different physical and chemical properties, show different reinforcing effects on the properties of ceria-zirconia-based materials. Previous studies have shown that the enhancing effect of these materials and the ceria-zirconia ratio on catalyst activity and stability, as well as studies on thermal stability at 1050... 

In this research, Chadormalou apatite concentrate was dissolved by 40% nitric acid and a solid to liquid ratio of 0.4 at 70 ° C for 2 hours, and its rare earth elements were dissolved. Recovery percents for Cerum, Neodymium and Lanthanum were 62.4, 48.7 and 49.6, respectively. In the solvent extraction step, the effect of HQ concentration as extractant, pH, temperature and phase ratio on the concentration of the adsorbed elements in organic phase, extraction percentage, distribution ratio and separation factor of rare earths were investigated. Organic solutions containing HQ in the kerosene alone pricipitated after contacting with PLS solutions. In order to prevent HQ pricipitation in the... 

Considering the demand for electronic and other products that rare earth elements are one of the necessary materials for their production, recovery of these elements plays an important roll today.The term “rare earth”, represents a group of 17 metalic elements with similar physical and chemical properties such as Sc,Y and lanthanides. Lanthanides are a group of elements with 57 to 71 atomic numbers and all of them except Pr, are present in earth crust.Some of these elements are available in phosphate concentrate(iron ore waste) of chadormalu in bafgh. Base on the analysis performed on apatite concatrate, it was represented that Ce,La and Nd elements are more than the others. So this research... 

Waste of iron ore concentrate production plant of Chadormalu contains apatite mineral. The content of rare earths elements (REEs) in apatite concentrate of Chadormalu is about one percent. However, considering apatite deposite and production rate, extraction of REEs from apatite is one of valuable source for production of REEs. Lanthanum, cerium and neodymium which have most application amonge other REEs and have the highest frequency in the apatite. Due to their similar physical and chemical properties, it is difficult to separate individual rare earths from each other and the separation process are too complicated. In this study, in order to extract REEs from apatite, it was leached by... 

There are two challenging problems with the physical properties of the recently discovered cuprate, Y3Ba5Cu8O19 δ (Y358): (1) the value of its transition temperature (Tc) and (2) its unknown crystal structure. While some reports argue that Tc of Y358 and its crystal structure are completely different from those of the YBa2Cu3O7 δʹ (Y123) compound, other reports indicate the similarity of both transition temperatures and XRD patterns (or crystal structure) of these materials. It has been suggested that these similarities are due to oxygen deficiency (δ) of Y3Ba5Cu8O19 δ or the decomposition of Y358 to Y123. In this thesis, we address these issues. At first, we have tried to answer the... 

The first study of the present research aims to the possibility of developing simple, accurate and selective potentiometric sensors for the detection of scandium ions in aqueous solution, which is done for the first time. In this study, a sensor array consisting of 17 miniaturized potentiometric sensors based on polymeric membranes containing various ion-extracting ligands were designed and fabricated. Ligands as the active component of the membranes included phosphine oxides and diamides of various organic acids, which were used in the extraction of rare earth metal ions. The possibility of using these extractants in the polymer matrix of membranes for the development of scandium-sensitive... 

Properties of stents are significantly dependent on the mechanical properties of the microtubes used in their construction. Therefore, investigating the influence of various factors on the mechanical behavior of magnesium microtubes employed in the fabrication of biodegradable stents can play an indispensable role in the development of the emerging industry of biodegradable stent manufacturing. In this dissertation, the effects of different parameters on the mechanical behavior of magnesium microtubes used in the construction of biodegradable stents have been examined. To achieve this, the objectives of this dissertation have been divided into three main sections. In the first section, a...