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tungsten
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Fabrication, Characterization and Field Emission Study of GLAD Tungsten Nanostructures
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Azimirad, Ruhollah (Supervisor)
Abstract
Recently nanostructure materials have used in various technologies and hence an extensive part of research focused on preparing and optimization of growth of nanostructure materials. Usually common procedure is based on a two-step process. First, construction a pre-layer by means of different deposition methods and then formation a nanostructure with a thermal treatment which increases the cost of research. Hence with one step method such as glancing angle deposition (GLAD ( it is possible to form a desirable structure with low cost. In this research Nano columns of tungsten was deposited on Si(133) by means of GLAD-RF sputtering without any heat treatment at substrate rotational speed ( )...
Investigating the Effect of Tungsten Nanoparticles on the Physical Properties of Polymer Composites
, M.Sc. Thesis Sharif University of Technology ; Musavi, Abbas (Supervisor) ; Shojaei, Akbar (Supervisor)
Abstract
The precise measurement of fluid flow in different fields of the industry is vitally important. In addition, due to enormous hydrocarbon reservoirs, Iran is the biggest owner of gas reservoirs in the world and exact measurement of fluids is of considerable importance to consumption or export. Ultrasonic flowmeters that are the most useful ones of them consist of three elements made of piezoelectric, impedance matching layer and backing material. In this study, on the contrary to former backing materials which usually use of titanium, tungsten, and aluminum oxide as a composite Filler, for the first time, tungsten oxide is used. In order to do this, composite samples were built of tungsten...
Reduction of Sulfur Content of Model Feed by Oxidative Process in them Presence of Carbon Structures Based W-Mo Nanocatalysts
, Ph.D. Dissertation Sharif University of Technology ; Kazemini, Mohammad (Supervisor) ; Rashidi, Alimorad (Supervisor) ; Hajjar, Zeinab (Co-Supervisor)
Abstract
In this research, molybdenum and tungsten catalysts modified with cobalt and nickel on a carbon support have been synthesized and investigated in the oxidation desulfurization process. A model fuel was used to evaluate the synthesized catalysts. This model fuel was n-decane. dibenzothiophene was also used as a sulfur model. The synthesized catalysts were subjected to various analyzes such as XRD, FTIR, Raman, BET-BJH, NH3-TPD, TEM and ICP-OES for structural evaluation. On the other hand, synthetic parameters such as metal loading rate, molar or weight ratio of secondary metal (cobalt and nickel) to primary metal (molybdenum and tungsten) and molar ratio of citric acid to primary metal as...