Loading...
Search for:
zakeri--r
0.101 seconds
Total 7083 records
Variation of the lateral Casimir force between corrugated conductors due to the presence of a dielectric slab
, Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 86, Issue 2 , 2012 ; 10502947 (ISSN) ; Soltani, M ; Zakeri, P ; Jafari, S. A ; Sharif University of Technology
APS
2012
Abstract
We investigate the lateral Casimir interaction between two corrugated conductors when they enclose a dielectric slab. The magnitude of the lateral Casimir force can be changed due to the presence of a dielectric slab between them, and it strongly depends on the thickness (d) and dielectric function of the slab and also on the position of the slab with respect to the conductors. In addition, the distance between the conductors (H) and their corrugation wavelengths play important roles in tuning the lateral Casimir interaction. For fixed d and H, quite interestingly, the magnitude of the lateral Casimir force varies when the position of the slab with respect to conductors changes, and it has a...
Pressureless sintering of ZrB 2 ceramics codoped with TiC and graphite
, Article International Journal of Refractory Metals and Hard Materials ; Volume 81 , 2019 , Pages 189-195 ; 02634368 (ISSN) ; Nemati, A ; Zakeri, M ; Shahedi Asl, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this research, the pressureless sintering of ZrB 2 composites were studied to obtain the highest densification and investigate the effects of TiC (2–10% wt) and graphite (1–2% wt) additives on the sinterability. The results showed that by adding TiC, the porosity and water absorption of the samples decreased, resulting in an increase in the density of the samples up to ~98% of the theoretical density. The addition of graphite and TiC reduced the surface oxide layers, improved the density and prevented the grain growth. The graphite additive reacted with B 2 O 3 and ZrO 2 and allowed the system to achieve a complete densification at 2000 °C. Both TiC and graphite additives were completely...
Enhancement of efficient Ag-S/TiO2 nanophotocatalyst for photocatalytic degradation under visible light
, Article Industrial and Engineering Chemistry Research ; Vol. 53, issue. 23 , 2014 , Pages 9578-9586 ; ISSN: 08885885 ; Vossoughi, M ; Zakeri, S. M. E ; Rahimi, M ; Sharif University of Technology
2014
Abstract
A new photocatalyst (Ag-S/PEG/TiO2) was synthesized by adding polyethylene glycol (PEG) to an efficient Ag-S/TiO2 photocatalyst, to obtain a photocatalyst that is highly active under visible light. In addition to Ag-S/PEG/TiO2, Ag-S/TiO2 and pure TiO2 were prepared to compare their properties and activities. Specifically, the morphologies and microstructures of the nanophotocatalysts were characterized by means of powder X-ray diffraction (XRD), N2 adsorption-desorption measurements, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy,...
Three dimensional finite element modeling of laser cladding of nickel alloy with 1.5wt.% and 3wt.% nano Ceo2 on the low carbon steel 1015
, Article ; 2011 Conference on Lasers and Electro-Optics: Laser Science to Photonic Applications, CLEO 2011, 1 May 2011 through 6 May 2011, Baltimore, MD , 2011 ; 9781557529107 (ISBN) ; Vaghefi, M ; Zakeri, S. S ; Seyedin, A ; Sharif University of Technology
2011
Abstract
Multilayer laser cladding process for the material properties of low carbon steel 1015 for workpiece and nickel alloy with 1.5 wt.% and 3 wt.% nano CeO2 as the powder particles is modeled. Finite Element Method (FEM) solutions of transient heat transfer and mass transfer equations in laser cladding process are presented. Geometry of the deposited material as well as temperature and thermal stress fields across the process area are calculated
Comprehensive study on the effect of SiC and carbon additives on the pressureless sintering and microstructural and mechanical characteristics of new ultra-high temperature ZrB2 ceramics
,
Article
Ceramics International
;
Volume 41, Issue 9, Part A
,
November
,
2015
,
Pages 11456–11463
;
02728842 (ISSN)
; Nemati, A
; Zakeri, M
; Tamizifar, M
; Samadi, H
;
Sharif University of Technology
Elsevier Ltd
2015
Abstract
The combined effects of SiC and carbon additives on the densification, structure and characteristics of pressureless sintered ZrB2 -SiC ceramic composites were studied. The ZrB2 -SiC (1-10wt%) composite powders were mixed by 1-2wt% carbon. The prepared powder mixtures were then cold-consolidated and sintered in argon environment in the temperature range of 1800-2100°C for 2h. The constituted phases and microstructural evolutions were studied using x-ray diffraction and scanning electron microscope equipped with an energy dispersive x-ray detector. The obtained results concluded that the densification was increased by extending the sintering time and also by prior holding...
All-optical flip-flop composed of a single nonlinear passive microring coupled to two straight waveguides
, Article Optics Communications ; Volume 282, Issue 3 , 2009 , Pages 427-433 ; 00304018 (ISSN) ; Mirzaee, M. A ; Farman, F ; Zakeri, S ; Sharif University of Technology
2009
Abstract
Microrings can have different hysteresis characteristics at their different resonance frequencies. They can be used as a multi-hysteresis optical component. In this paper an optical D-flip-flop circuit composed of a single nonlinear passive microring coupled to two straight waveguide based on the Kerr effect is proposed. The proposed circuit can operate as an optical digital circuit which synchronizes input DATA with the CLOCK of the circuit. A simple analytical model for hysteresis design and the transient analysis of the proposed D-flip-flop are presented. According to our model, the switching time of the flip-flop is in the order of 10 ps. Crown Copyright © 2008
Characterization of nanostructured biodegradable Zn-Mn alloy synthesized by mechanical alloying
, Article Journal of Alloys and Compounds ; Volume 735 , 2018 , Pages 1319-1327 ; 09258388 (ISSN) ; Khaleghpanah, S ; Sheibani, S ; Khakbiz, M ; Zakeri, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this study, nanostructured biodegradable pure Zn, Zn-4 wt. % Mn and Zn-24 wt % Mn alloys were produced by 20 h mechanical alloying and consequent cold pressing and sintering. Structural evolutions were investigated using the X-ray diffraction technique. Also, the microstructure was characterized by scanning electron microscopy. The effects of alloy composition on density, mechanical properties, corrosion behavior in Hank's solution, cell viability and cell attachment were investigated. Crystallite size of the synthesized alloys after 20 h of milling reached to less than 40 nm and remained less than 80 nm after consolidation and sintering for 1 h. Alloys contain MnZn13 as second phase...
Simualtion of Two-Phase Gas-Solid Flow in Electrostatic Precipitator to Increase Particulate Collection Efficiency Using Plate with Aerodynamic Bulges
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor) ; Zakeri, Ramin (Supervisor)
Abstract
Electrostatic precipitators (ESPs) are widely recognized for their pivotal role in the collection of dust and particulate matter. ESPs are essential to ensure a particle- and dust-free atmosphere in industrial and non-industrial work environments. With the ever-increasing significance of maintaining air quality at the desired standards, the role of ESPs has gained paramount importance in mitigating airborne pollutants and protecting public health. Achieving higher collection efficiency for particulate matter and attaining cleaner air is of great importance in the design and selection of precipitators. On the other hand, particle collection efficiency is considered as a crucial factor for ESP...
Compact and secure design of masked AES S-box
, Article 9th International Conference on Information and Communications Security, ICICS 2007, Zhengzhou, 12 December 2007 through 15 December 2007 ; Volume 4861 LNCS , 2007 , Pages 216-229 ; 03029743 (ISSN); 9783540770473 (ISBN) ; Salmasizadeh, M ; Moradi, A ; Tabandeh, M ; Manzuri Shalmani, M. T ; Sharif University of Technology
Springer Verlag
2007
Abstract
Composite field arithmetic is known as an alternative method for lookup tables in implementation of S-box block of AES algorithm. The idea is to breakdown the computations to lower order fields and compute the inverse there. Recently this idea have been used both for reducing the area in implementation of S-boxes and masking implementations of AES algorithm. The most compact design using this technique is presented by Canright using only 92 gates for an S-box block. In another approach, IAIK laboratory has presented a masked implementation of AES algorithm with higher security comparing common masking methods using Composite field arithmetic. Our work in this paper is to use basic ideas of...
Individual and interaction effects of operating parameters on the photocatalytic degradation under visible light illumination: response surface methodological approach
, Article Canadian Journal of Chemical Engineering ; Volume 95, Issue 7 , 2017 , Pages 1228-1235 ; 00084034 (ISSN) ; Rahimi, M ; Zakeri, S. M. E ; Mahinpey, N ; Vossoughi, M ; Qanbarzadeh, M ; Sharif University of Technology
2017
Abstract
In this study, for the first time a statistical analysis based on the response surface methodology (RSM) was employed to investigate individual and interaction effects of key operating parameters of the photocatalytic degradation under visible-light irradiation using Ag-S/PEG/TiO2. Ag-S/PEG/TiO2 is a visible-light-driven photocatalyst and was synthesized (based on earlier research) by co-doping of TiO2 with silver and sulphur and addition of polyethylene glycol (as a reagent template). In addition, the model pollutant was methylene orange (MO) and the studied operating parameters included the photocatalyst loading, initial concentration of the pollutant, and pH of the solution. The...
Photocatalytic removal of 2-nitrophenol using silver and sulfur co-doped TiO2 under natural solar light
, Article Water Science and Technology ; Volume 72, Issue 3 , 2015 , Pages 339-346 ; 02731223 (ISSN) ; Delparish, A ; Toufigh Bararpour, S ; Abedini Najafabadi, H ; Zakeri, S. M. E ; Vossoughi, M ; Sharif University of Technology
IWA Publishing
2015
Abstract
To overcome the drawback of poor solar light utilization brought about by the narrow photoresponse range of TiO2, a silver and sulfur co-doped TiO2 was synthesized. Using the prepared catalyst, solar photocatalytic degradation of 2-nitrophenol (2-NP) by a TiO2-based catalyst was studied for the first time. Effects of the co-doping on the structural, optical and morphological properties of the synthesized nanoparticles were investigated by different characterization methods: X-ray diffraction, N2 adsorption-desorption measurements, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, UV-visible diffuse reflectance spectroscopy and Fourier...
Photocatalytic degradation of dibenzothiophene using La/PEG-modified TiO2 under visible light irradiation
, Article Research on Chemical Intermediates ; Jan , 2014 , pp. 1-17 ; Vossoughi, M ; Feilizadeh, M ; Zakeri, S. M. E ; Mohammadi, M. M ; Rashtchian, D ; Yoosefi Booshehri, A ; Sharif University of Technology
2014
Abstract
While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is investigated for the...
Photocatalytic degradation of dibenzothiophene using La/PEG-modified TiO2 under visible light irradiation
,
Article
Research on Chemical Intermediates
;
Volume 41, Issue 7
,
July
,
2015
,
Pages 4151-4167
;
09226168 (ISSN)
; Vossoughi, M
; Feilizadeh, M
; Zakeri, S. M. E
; Mohammadi, M. M
; Rashtchian, D
; Yoosefi Booshehri, A
;
Sharif University of Technology
Kluwer Academic Publishers
2015
Abstract
While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low levels of pollutants such as dibenzothiophene (DBT) is occasionally reported. In the present work, lanthanide/polyethylene glycol-modified TiO2 (La/PEG/TiO2 ) has been successfully synthesized by a sol-gel method. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-Vis diffusive reflectance spectroscopy, and energy dispersive X-ray analysis. Moreover, the photocatalytic degradation of DBT under visible light irradiation is...
Design, Expression, and Evaluation of Nanoparticle Structure Containing Malaria Vaccine Candidate Antigen by Self-assembled Peptide Nanoparticles (SAPNs) and Confirmation of its Antigenicity Using Serum of Malaria Patients
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Abouei Mehrizi, Akram (Supervisor) ; Sardari, Soroush (Co-Supervisor) ; Zakeri, Sedigheh (Co-Supervisor)
Abstract
Malaria is one of the most important infectious diseases in the tropical and subtropical regions of the world and is caused in humans by the bite of the female Anopheles mosquito of five species of Plasmodium. According to the World Health Organization, about 229 million people worldwide were infected in 2019 by the disease, and 409,000 people died from the disease. Resistance of the parasite against drugs and resistance of vectors to insecticides and larvicides, which prevents the elimination and eradication of malaria, shows the need for new strategies, such as having an effective vaccine against this disease. In the second generation of vaccines, to develop malaria vaccines, recombinant...
Sequence dependence of the binding energy in chaperone-driven polymer translocation through a nanopore
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 83, Issue 1 , January , 2011 ; 15393755 (ISSN) ; Ejtehadi, M. R ; Metzler, R ; Sharif University of Technology
2011
Abstract
We study the translocation of stiff polymers through a nanopore, driven by the chemical-potential gradient exerted by binding proteins (chaperones) on the trans side of the pore. Bound chaperones prevent backsliding through the pore and, therefore, partially rectify the polymer passage. We show that the sequence of chain monomers with different binding affinity for the chaperones significantly affects the translocation dynamics. In particular, we investigate the effect of the nearest-neighbor adjacency probability of the two monomer types. Depending on the magnitude of the involved binding energies, the translocation speed may either increase or decrease with the adjacency probability. We...
First passage time distribution of chaperone driven polymer translocation through a nanopore: Homopolymer and heteropolymer cases
, Article Journal of Chemical Physics ; Volume 135, Issue 24 , 2011 ; 00219606 (ISSN) ; Metzler, R ; Ejtehadi, M. R ; Sharif University of Technology
2011
Abstract
Combining the advection-diffusion equation approach with Monte Carlo simulations we study chaperone driven polymer translocation of a stiff polymer through a nanopore. We demonstrate that the probability density function of first passage times across the pore depends solely on the Péclet number, a dimensionless parameter comparing drift strength and diffusivity. Moreover it is shown that the characteristic exponent in the power-law dependence of the translocation time on the chain length, a function of the chaperone-polymer binding energy, the chaperone concentration, and the chain length, is also effectively determined by the Péclet number. We investigate the effect of the chaperone size on...
Reply: Abedpour, asgari, and tabar
, Article Physical Review Letters ; Volume 106, Issue 20 , 2011 ; 00319007 (ISSN) ; Asgari, R ; Tabar, M. R. R ; Sharif University of Technology
2011
Irreversibility in response to forces acting on graphene sheets
, Article Physical Review Letters ; Volume 104, Issue 19 , May , 2010 ; 00319007 (ISSN) ; Asgari, R ; Tabar, M. R. R ; Sharif University of Technology
2010
Abstract
The amount of rippling in graphene sheets is related to the interactions with the substrate or with the suspending structure. Here, we report on an irreversibility in the response to forces that act on suspended graphene sheets. This may explain why one always observes a ripple structure on suspended graphene. We show that a compression-relaxation mechanism produces static ripples on graphene sheets and determine a peculiar temperature Tc, such that for T
Analysis of design goals of cryptography algorithms based on different components
, Article Indonesian Journal of Electrical Engineering and Computer Science ; Volume 23, Issue 1 , 2021 , Pages 540-548 ; 25024752 (ISSN) ; Aref, M. R ; Khorshiddoust, R. R ; Sharif University of Technology
Institute of Advanced Engineering and Science
2021
Abstract
Cryptography algorithms are a fundamental part of a cryptographic system that is designed and implemented to increase information security. They are the center of attention of experts in the information technology domains. Although the cryptography algorithms are implemented to attain the goals such as confidentially, integrity, and authenticity of designing, but other matters that must be noticed by designers include speed, resource consumption, reliability, flexibility, usage type, and so on. For the useful allocation of hardware, software, and human resources, it is important to identify the role of each of the factors influencing the design of cryptographic algorithms to invest in the...
Conservation of statistical results under the reduction of pair-contact interactions to solvation interactions
, Article Physical Review E - Statistical, Nonlinear, and Soft Matter Physics ; Volume 72, Issue 6 , 2005 ; 15393755 (ISSN) ; Farzami, R. R ; Ejtehadi, M. R ; Sharif University of Technology
2005
Abstract
We show that the hydrophobicity of sequences is the leading term in Miyazawa-Jernigan interactions. Being the source of additive (solvation) terms in pair-contact interactions, they were used to reduce the energy parameters while resulting in a clear vector manipulation of energy. The reduced (additive) potential performs considerably successful in predicting the statistical properties of arbitrary structures. The evaluated designabilities of the structures by both models are highly correlated. Suggesting geometrically nondegenerate vectors (structures) as proteinlike structures, the additive model is a powerful tool for protein design. Moreover, a crossing point in the log-linear diagram of...