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silicon-nitride
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Investigation of Si3n4 Nano Particle Addition on the Hardening Behavior of Anodized Coated 1050 Aluminum Alloy
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor)
Abstract
In the present study, it has been tried out to increase the hardness and wear resistance of anodized aluminum coating byadding Si3N4 nanoparticles to the anodizing bath and making a composite coating. In order to investigate the influence of other effective parameters on the properties of anodized coating before the compositing process, hardness and thickness were optimized in the Sulphoric/oxalic bath using design of experimental method (central composite design). The properties of these coatings are dependent on various parameters among which time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were considered in the present study. Analysis of...
Complete steric exclusion of ions and proton transport through confined monolayer water
, Article Science ; Volume 363, Issue 6423 , 2019 , Pages 145-148 ; 00368075 (ISSN) ; Hu, S ; Esfandiar, A ; Lozada Hidalgo, M ; Wang, F. C ; Yang, Q ; Tyurnina, A. V ; Keerthi, A ; Radha, B ; Geim, A. K ; Sharif University of Technology
American Association for the Advancement of Science
2019
Abstract
It has long been an aspirational goal to create artificial structures that allow fast permeation of water but reject even the smallest hydrated ions, replicating the feat achieved by nature in protein channels (e.g., aquaporins). Despite recent progress in creating nanoscale pores and capillaries, these structures still remain distinctly larger than protein channels. We report capillaries made by effectively extracting one atomic plane from bulk crystals, which leaves a two-dimensional slit of a few angstroms in height. Water moves through these capillaries with little resistance, whereas no permeation could be detected even for such small ions as Na + and Cl − . Only protons (H + ) can...
Comprehensive simulation of the effects of process conditions on plasma enhanced chemical vapor deposition of silicon nitride
, Article Semiconductor Science and Technology ; Volume 23, Issue 9 , 22 August , 2008 ; 02681242 (ISSN) ; Ilati, H ; Rashidian, B ; Sharif University of Technology
2008
Abstract
A numerical model for the deposition of silicon nitride using silane and ammonia mixture in a radio frequency plasma reactor has been developed. Plasma enhanced chemical vapor deposition process is simulated by combined analysis for the glow discharge, fluid flow and chemical reactions. The main goal is to investigate the effect of variations of the process parameters on the deposition rate, and uniformity of the resulting layer. The approach used is based on the theoretical partial differential equation models, without any empirical approximation of the critical data being used. Owing to the fact that the relevant equations are highly nonlinear, the discretization method is of great...