Search for: electron
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Article Physica E: Low-dimensional Systems and Nanostructures ; Volume 40, Issue 9 , August , 2008 , Pages 2965–2972 ; Non-Equilibrium Green's function ; Gholami, M. R. (Mohammad Reza) ; Monajjemi, M ; Ganji, M. D ; Sharif University of Technology
The electron transport characteristics of a 1,10-dimethylene-1,10-dicarba-closo-decaborane (10-vertex carborane) single molecular conductor is investigated via the density functional-based non-equilibrium Green's function (DFT-NEGF) method. We consider three configurations for the molecular wire sandwiched between two Au(1 0 0) electrodes: the hollow site, top site and bridge site positions. Our results show that the energetically favorable hollow site configuration has a higher current intensity than the other configurations. The projection of the density of states (PDOS) and the transmission coefficients T(E) of the two-probe system at zero bias are analyzed, and it suggests that the...
Article IPAC 2014: Proceedings of the 5th International Particle Accelerator Conference ; Jul , 2014 , p. 2075-2077 ; Khosroabad, I H ; Amiri, S ; Ghasem, H ; Lamehi Rachti, M ; Rahighi, J ; Sharif University of Technology
In this paper the effect of emittance on the relevant issues of the synchrotron radiation sources, optics and beamline design for two values of emittance, e
x=3.278 and 0.937 nm.rad, suggested for the Iranian Light Source Facility lattice design, have been discussed. The effect of spot size and divergence of the electron beam, and strength of the bending magnet field, have been considered in the calculations. The results show that reducing of emittance, increases the brilliance of the undulator by factor 5, and decrease the foot print on the optical elements and spot size of photon beam on the sample by a factor of about 2
Book ; Outland, Jonathan ; King, David R ; Lee, Jae Kyu ; Liang, Ting-Peng ; Turban, Deborrah C
Springer International Publishing AG 2018
Article Solid-State Electronics ; Volume 122 , 2016 , Pages 37-44 ; 00381101 (ISSN) ; Sharif University of Technology
Elsevier Ltd 2016
We present an explicit solution of carrier and field distributions in abrupt PN junctions under equilibrium. An accurate logarithmic numerical method is implemented and results are compared to the analytical solutions. Analysis of results shows reasonable agreement with numerical solution as well as the depletion layer approximation. We discuss extensions to the asymmetric junctions. Approximate relations for differential capacitance C-V and current-voltage I-V characteristics are also found under non-zero external bias
M.Sc. Thesis Sharif University of Technology ; Sarvari, Reza ; Kolahdouz Esfahani, Mohammad Reza
In recent years, flexible electronics have started to attract a tremendeos amount of attention, partly on its remarkable growth in new technologies like IoT, wearable electronics, personal and health care devices. This emerging field offers many advantages compared to its traditional rigid counterparts, such as bendability, stretchablity, recyclability and biocompatibility. Inkjet printing is one of the most promising method for realizing flexible electronics due to its low-investment cost, fully additive nature, low material westage, relatively low temperature process and non-contact patterning.A printed circuit board (PCB), is undoubtedly a vital part of any electronics systems. So,...
Article Scientia Iranica ; Volume 20, Issue 3 , 2013 , Pages 637-646 ; 10263098 (ISSN) ; Takhtaei, B ; Mohajeri, J ; Sharif University of Technology
Eslami and Talebi (2011)  proposed an untraceable electronic cash scheme and claimed that their scheme protects the anonymity of customers, detects the identity of double spenders and provides the date attachability of coins to manage the bank database. In this paper, illustrating Eslami and Talebi's scheme, as one of the latest untraceable electronic cash schemes, and showing its weaknesses (in fulfilling the properties of perceptibility of double spender, unforgeability and date attainability of coins) and its faults (related to exchange protocol), we propose a new untraceable electronic cash scheme which is immune to the weaknesses of the former. Our scheme contains anonymity,...
M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan
Due to the considerable changes taken place in the economic structures and financial systems, the role of banks as substantial economic organizations has become more important and highlighted. Therefore, it is required for banks to develop their services with the world-wide growth of information technology in order to meet the rising online needs of their customers. This goal could be better achieved by the alignment of electronic banking services with a perfect strategy for IT service management which has been made up of widely accepted best practices. Accordingly, the aim of this thesis is establishing a guideline from which banks can plan, implement, and measure their electronic banking...
M.Sc. Thesis Sharif University of Technology ; Moayedi, Vafa
The main purpose of my research is to present a predictive E-Commerce plan for Iran. For many people the term "electronic commerce" means shopping on the part of the Internet called the World Wide Web, but other technologies such as wireless transmissions on mobile telephone and personal digital assistant devices are also included. In our thesis the term Electronic Commerce or (E-Commerce) is used in its broadest sense, and includes all business activities conducted using electronic data transmission technologies. In Iran e-commerce has achieved an important role and is facing remarkable acceptance in trade operations, therefore my study focuses on the development of E-Commerce model in...
Anomalous magnetic moment of hot quarks, inverse magnetic catalysis, and reentrance of the chiral symmetry broken phase, Article Physical Review D - Particles, Fields, Gravitation and Cosmology ; Vol. 90, issue. 10 , 2014 ; ISSN: 15507998 ; Sadooghi, N ; Sharif University of Technology
The effect of the anomalous magnetic moment of quarks on thermodynamic properties of the chiral condensate is studied, using a two-flavor Nambu-Jona-Lasinio model at finite temperature T, chemical potential μ, and in the presence of a uniform magnetic field eB. To this purpose, the Schwinger linear-in-B ansatz for the anomalous magnetic moment of quarks is considered in terms of the nonperturbative Bohr magneton. In a two-dimensional flavor space, it leads to the correction TSch=κQeB in the energy dispersion relation of quarks. Here, Q is the quark charge matrix. We consider three different sets for κ, and numerically determine the dependence of the constituent quark mass on T,μ, and eB for...
Article Journal of Alloys and Compounds ; Vol. 597 , June , 2014 , pp. 142-147 ; ISSN: 09258388 ; Kokabi, A. H ; Dolati, A ; Sharif University of Technology
The microstructural characteristic of HSLA welds containing different amounts of titanium were evaluated carefully. It was observed that the microstructure of welds consisted of ferrite with mixed morphologies, and small amounts of pearlite and martensite-austenite micro-constituents. Because of insufficient time for diffusion of carbon, formation of pearlite lamellae could not be completed in the weld region. Martensite was formed from carbon enrichment of austenite during nucleation and growth of acicular ferrite and bainitic ferrite. While coarse manganese sulfide particles had weak interface strength with matrix and formed some micro-fissures; increasing titanium amount of welds...
Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 92, Issue 3 , 2015 ; 15393755 (ISSN) ; Taher Ghahramani, F ; Shafiee, A ; Sharif University of Technology
American Physical Society 2015
We examine the olfactory discrimination of left- and right-handed enantiomers of chiral odorants based on the odorant-mediated electron transport from a donor to an acceptor of the olfactory receptors embodied in a biological environment. The chiral odorant is effectively described by an asymmetric double-well potential whose minima are associated to the left- and right-handed enantiomers. The introduced asymmetry is considered an overall measure of chiral interactions. The biological environment is conveniently modeled as a bath of harmonic oscillators. The resulting spin-boson model is adapted by a polaron transformation to derive the corresponding Born-Markov master equation with which we...
Article Journal of Applied Physics ; Volume 117, Issue 14 , April , 2015 ; 00218979 (ISSN) ; Yazdani, E ; Sadighi Bonabi, R ; Anvari, A ; Hora, H ; Sharif University of Technology
American Institute of Physics Inc 2015
The interaction of the sub-picosecond UV laser in sub-relativistic intensities with deuterium is investigated. At high plasma temperatures, based on the quantum correction in the collision frequency, the electron heating and the ion block generation in plasma are studied. It is found that due to the quantum correction, the electron heating increases considerably and the electron temperature uniformly reaches up to the maximum value of 4.91-×-107-K. Considering the quantum correction, the electron temperature at the laser initial coupling stage is improved more than 66.55% of the amount achieved in the classical model. As a consequence, by the modified collision frequency, the ion block is...
Article Iranian Journal of Physics Research ; Volume 17, Issue 2 , 2017 , Pages 263-268 ; 16826957 (ISSN) ; Zavarian, A. A ; Hafezi, F ; Sharif University of Technology
Isfahan University of Technology 2017
In this paper, the vacuum film deposition through electron beam evaporation has been reviewed and the effect of magnetic field on the operation of this system has been explained. Then, the magnetic field distribution due to magnetic components configuartion of a commercial evaporation source with 270-degree electron beam gun (manufactured by Sharif University Branch of ACECR), has been simulated by means of a finite element software, ANSYS. The simulation result was verified by comparing with the results obtained from measurement by Hall Effect sensor. Furthermore, by using the ray-tracing capability of the software, the capability of the magnetic lens of this device for electron beam...
Article Physical Review B - Condensed Matter and Materials Physics ; Volume 80, Issue 15 , 2009 ; 10980121 (ISSN) ; Capone, M ; Nafari, N ; Sharif University of Technology
The effect of a solid-vacuum interface on the properties of a strongly coupled electron-phonon system is analyzed using dynamical mean-field theory to solve the Holstein model in a semi-infinite cubic lattice. Polaron formation is found to occur more easily, i.e., for a weaker electron-phonon coupling, on the surface than in the bulk. On the other hand, the metal-insulator transition associated with the binding of polarons takes place at a unique critical strength in the bulk and at the surface. © 2009 The American Physical Society
Oxidative transformation of organic compounds using bis(1,10- phenanthroline)silver(II) peroxydisulfate as a twin catalyst/oxidant, Article Journal of the Iranian Chemical Society ; Volume 5, Issue SUPPL.1 , 2008 , Pages S108-S112 ; 1735207X (ISSN) ; Bahadori, M ; Rafiee, E ; Bagherzadeh, M ; Sharif University of Technology
Iranian Chemical Society 2008
The mild and efficient oxidation of a variety of organic functional groups with a twin catalyst/oxidant, bis(phenanthroline)silver(II) peroxydisulfate, [Ag(phen)2]S2O8, is reported. This reagent shows high selectivity and the type of obtained products and the extent of oxidation are strongly dependent to the type of the functional groups and oxidant/substrate molar ratios
Article International Journal of Modern Physics B ; Volume 21, Issue 13-14 , 2007 , Pages 2134-2144 ; 02179792 (ISSN) ; Subaşi, A. L ; Esfarjani, K ; Fazeli, S. M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd 2007
Two-dimensional (2D) electron systems in the presence of disorder are of interest in connection with the observed metal-insulator transition in such systems. We use density functional theory in its local-spin density approximation (LSDA) to calculate the ground-state energy of a 2D electron system in the presence of remote charged impurities which up on averaging provides disorder. The inverse compressibility calculated from the ground-state energy exhibits a minimum at a critical density controlled by the disorder strength. Our findings are in agreement with experimental results. © World Scientific Publishing Company
Article Physical Review B - Condensed Matter and Materials Physics ; Volume 75, Issue 17 , 2007 ; 10980121 (ISSN) ; Langari, A ; Sharif University of Technology
The anisotropic Kondo necklace model in two and three dimensions is treated as a genuine model for magnetic to Kondo singlet quantum phase transitions in the heavy fermion compounds. The variation of the quantum critical point with anisotropy parameters has been investigated previously in the zero-field case. Here, we extend the treatment to finite fields using a generalized bond operator representation including all triplet states. The variation of critical tc with magnetic field and the associated phase diagram is derived. The influence of anisotropies and the different g factors for localized and itinerant spins on the field dependence of tc is also investigated. It is found that three...
Article Physical Review B - Condensed Matter and Materials Physics ; Volume 74, Issue 2 , 2006 ; 10980121 (ISSN) ; Thalmeier, P ; Sharif University of Technology
We have studied the effect of anisotropies on the quantum phase transition of the Kondo necklace model in dimensions D=1, 2, and 3. Both the anisotropy δ of the intersite interaction term and anisotropy Δ of the on-site Kondo interaction have been included. We use a bond operator method with constraints implemented in mean-field approximation. Starting from the paramagnetic phase we determine the critical ratio (t J)c of the quantum critical point and associated scaling exponents of the Kondo-singlet gap. We show that in the case of easy-axis type anisotropy δ>1 a qualitatively different behavior in comparison to the conventional Kondo necklace model with (δ,Δ) = (0,1) appears. We have also...
Article Proceedings of the 9th International Conference on New Diamond, Tokyo, 26 March 2004 through 29 March 2004 ; Volume 13, Issue 11-12 , 2004 , Pages 2125-2130 ; 09259635 (ISSN) ; Vesaghi, M. A ; Esfarjani, K ; Shafiekhani, A ; Sharif University of Technology
A new model to calculate electronic states of the diamond vacancies has been developed using many body techniques. This model is based on physical assumptions of previous molecular models but does not use configuration interaction. Present model allows an accurate and unified treatment of electronic levels and related eigen functions for diamond vacancies, in addition to transition energies of the first dipole-allowed transitions in the neutral (V0) and negatively charged (V-) vacancies, GR1 and ND1 band. For the first time, we calculated their optical transition intensities. For obtaining these results, we solved a generalized form of the Hubbard Hamiltonian, which consists of all...
Article New Astronomy Reviews ; Volume 48, Issue 1-4 , 2004 , Pages 287-292 ; 13876473 (ISSN) ; O'Neill, T. J ; Akyüz, A ; Samimi, J ; Zych, A. D ; Sharif University of Technology
A prototype balloon-borne telescope is being constructed for γ-ray observations in the MeV energy range. The Tracking and Imaging Gamma-Ray Experiment (TIGRE) uses multi-layers of thin silicon detectors to track and measure the energy losses of Compton recoil electrons. When combined with the direction and energy of the Compton scattered γ-ray a unique incident direction for each photon event is determined. This facilitates background rejection, improved sensitivity and image reconstruction. The converter/tracker also serves as an electron-positron pair detector for γ-rays up to 100 MeV. The initial continental US flight will be used to determine the sub-orbital atmospheric backgrounds and...