Sharif University of Technology is a public research university in Tehran, Iran known traditionally to be first choice of top ranked Iranian high school and university students in engineering and physical science. The university is located in the Tarasht neighborhood of Tehran within close proximity of Azadi Square, and also has an international campus in Kish, a resort island in the Persian Gulf.Established in 1966, it was formerly named the Aryamehr University of Technology and for a short period after the 1979 revolution, the university was called Tehran University of Technology. Following the revolution the university was named after Majid Sharif Vaghefi, a former student who was killed in 1975.Today, the university provides both undergraduate and graduate programs in 15 main departments. The student body consists of about 6,000 undergraduate students and 4,700 graduate students from all the 30 provinces of Iran. Funding for Sharif University is provided by the government and through private funding. Undergraduate admission to Sharif is limited to the top 1 percent of students who pass the national entrance examination administered annually by the Iranian Ministry of Science, Research and Technology.In the 2013 Academic Ranking of World Universities Engineering/Technology and Computer science rankings, SUT is ranked 5th in the Middle East. It is in the top 251-275 universities in the world and 37th in Asia in the 2014 Times Higher Education World University Rankings. SUT also ranked 1st in the Middle East, 6th in Asia, and 27th in the world in Times Higher Education's top 100 universities under 50. Wikipedia.
Tavazoei M.S.,Sharif University of Technology
Automatica | Year: 2010
In this paper, it is shown that the fractional-order derivatives of a periodic function with a specific period cannot be a periodic function with the same period. The fractional-order derivative considered here can be obtained based on each of the well-known definitions Grunwald-Letnikov definition, Riemann-Liouville definition and Caputo definition. This concluded point confirms the result of a recently published work proving the non-existence of periodic solutions in a class of fractional-order models. Also, based on this point it can be easily proved the absence of periodic responses in a wider class of fractional-order models. Finally, some examples are presented to show the applicability of the paper achievements in the solution analysis of fractional-order systems. © 2010 Elsevier Ltd. All rights reserved.
Khavasi A.,Sharif University of Technology
Optics Letters | Year: 2013
Li's Fourier factorization rules [J. Opt. Soc. Am. A 13, 1870 (1996)] should be applied to achieve a fast convergence rate in the analysis of diffraction gratings with the Fourier modal method. I show, however, that Li's inverse rule cannot be applied for periodic patterns of graphene when the conventional boundary condition is used. I derive an approximate boundary condition in which a nonzero but sufficiently small height is assumed for the boundary. The proposed boundary condition enables us to apply the inverse rule, leading to a significantly improved convergence rate. A periodic array of graphene ribbons is in fact a special type of finite-conductivity strip grating, and thus the proposed approach is also applicable to these kinds of structures. © 2013 Optical Society of America.
Akhavan O.,Sharif University of Technology
Carbon | Year: 2010
Graphene thin films with very low concentration of oxygen-containing functional groups were produced by reduction of graphene oxide nanosheets (prepared by using a chemical exfoliation) in a reducing environment and using two different heat treatment procedures (called one and two-step heat treatment procedures). The effects of heat treatment procedure and temperature on thickness variation of graphene platelets and also on reduction of the oxygen-containing functional groups of the graphene oxide nanosheets were studied by atomic force microscopy and X-ray photoelectron spectroscopy. While formation of the thin films composed of single-layer graphene nanosheets with minimum thickness of 0.37 nm and nearly without any functional group bonds was observed at the high temperature of 1000 °C in the one-step reducing procedure, similar high quality graphene thin films were obtained at the lower temperature of 500 °C in our two-step reducing temperature. The results also indicated possibility of efficient reduction of the graphene oxide thin films at even lower heat treatment temperatures (≤500 °C). © 2009 Elsevier Ltd. All rights reserved.
Asghari M.,Sharif University of Technology
International Journal of Engineering Science | Year: 2012
The couple stress theory is a non-classical continuum theory which is capable to capture size effects in small-scale structures. This property makes it appropriate for modeling the structures in micron and sub-micron scales. The purpose of this paper is the derivation of the governing motion equations and boundary conditions for the geometrically nonlinear micro-plates with arbitrary shapes based on the modified version of the couple stress theory. The consistent boundary conditions are provided at smooth parts of the plate periphery and also at the sharp corners of the periphery using variational approach. © 2011 Elsevier Ltd. All rights reserved.
Tavazoei M.S.,Sharif University of Technology
IEEE Industrial Electronics Magazine | Year: 2012
Proportional-integral (PI) controllers are the most common form of feedback used in industrial applications today . The use of proportional and integral feedback also has a long history of practical applications . For example, in the middle of the 18th century, centrifugal governors as the proportional feedback were applied to regulate the speed of windmills . By the 19th century, it was known that using integral feedback could remove the offsets appearing in working with governors . At present, PI control, still a very basic form of feedback, is also one of the first solutions often considered in the control of industrial systems . On the other hand, in some applications, using the PI controller in its traditional form may not be satisfactory, and a more advanced controller is needed to achieve control objectives. In such cases, modified versions of the PI controller have been proposed to enhance the controller's performance. The fractional-order PI controller is one of these modified versions, and it is attracting increased interest in control system design uses , . The idea of using such a controller originated with fractional calculus, known as a generalization for classical calculus . The following section presents a brief review of recent fractional calculus applications in control system design. © 2011 IEEE.