Sharif Digital Repository

Nowadays, thin film alloy deposition has much importance. These alloys are used for various opto-electronic device applications such as liquid crystal displays, flat panel displays, plasma displays, solar cells and computer memories. Exact control of elements ratio in alloy is one of the important issues in deposition of thin film alloys. In alloy deposition with electron beam gun method from its elements, uniformity improvement of each layer is a way to maintain elements ratio in different parts of sample. This uniformity has much importance especially in optical coatings such as high quality antireflection coatings, highly selective filters and low loss reflectance coatings. In this... 

In the present work, aluminothermic reduction of vanadium pentoxide have been used to produce aluminium vanadium alloys. The effect of addition of lime and excess aluminium on the produced alloy was studied. The experiments were carried out in air and in argon. The alloys microstructure were analyzed bu light and scanning electron microscopy. Other methods such as XRD, XRF, ICP, AAS and titration were employed to analyzed the alloy and the slag. It was found that the addition of lime and excess aluminium increase the yield of the alloy. Vanadium recovery was not affected by the atmosphere used.
 

In this work, Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) method was applied to investigate the decomposition routs of -halo alcohols on Ni(111) and Cu(111) crystallographic planes and Ni2Cu1(111) and Ni1Cu2(111) alloys. UBI-QEP calculates energetics, H and E, along reactions routes using heats of atomic adsorption as empirical inputs and in this way avoids needs to be very specific about every system. The results of analysis of -halo-propanols on Ni and Cu surfaces are in good agreement with experimental findings; namely in the formation of carbon-monoxide, ethylene, water and hydrogen over Ni and propene and water over Cu. Predicted activity of -halo-propanols,... 

The purpose of this project is the prediction of the activation barriers and enthalpy for elementary steps in the process of Fischer-Tropsch over the surfaces of Fe, Cu and Fe/Cu alloys catalyst by using of UBI-QEP method aiming at finding prediction of the activity and selectivity on the basis of energy criteria.
UBI-QEP methods is based on conservation of bond index of adsorbed molecules and follow the quadratic exponential potential for energy, calculate the enthalpy and activation barriers of reaction pathways in a heterogeneous catalytic process and select the most desirable path to take.
The elementary steps such as dissociation of CO, hydrogenation of carbidic carbon, C-C...