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    The TCVD growth of CNTs over copper-silver-palladium nanoparticles prepared by DC magnetron sputtering

    , Article Acta Physica Polonica A ; Volume 137, Issue 6 , 2020 , Pages 1075-1079 Rezaee, S ; Mardani, M ; Shakoury, R ; Sharif University of Technology
    Polish Academy of Sciences  2020
    Abstract
    In this study, we investigate the use of catalytic copper-silver-palladium substrates for the growth of multiwalled carbon nanotubes via the thermal chemical vapor deposition. These layers are comprised of nanocrystals of Cu2O, CuO, Ag, Pd, Cu, and PdO and were grown using a DC magnetron sputtering method. Scanning electron microscopy characterizations confirmed the significant growth of carbon nanotubes on the catalytic layer. A comparison of the growth of nanotubes indicated that the thickness of the catalytic layers has a significant impact on the quality and the diameter of the carbon nanotubes. Two major peaks were seen in the Raman spectrum. The formation of graphite multiwalled... 

    Stereometric analysis of TiO2 thin films deposited by electron beam ion assisted

    , Article Optical and Quantum Electronics ; Volume 52, Issue 5 , 2020 Shakoury, R ; Arman, A ; Ţălu, Ş ; Dastan, D ; Luna, C ; Rezaee, S ; Sharif University of Technology
    Springer  2020
    Abstract
    The micromorphology and semiconductor properties of TiO2 thin films growth using different ion beam energies have been finely analyzed using atomic force microscopy (AFM), ultra-violet visible (UV–visible) spectroscopy and stereometric analysis. The AFM measurements and surface stereometric analysis are essential for the accurate characterization of the 3-D surface topographic features and allow the determination of the 3-D surface texture parameters that influence the optical properties of the material. The samples were divided into four groups to discuss the obtained results, according to the ion beam energy applied in the sample preparation. The results obtained from experimental... 

    The effect of thickness and film homogeneity on the optical and microstructures of the ZrO2 thin films prepared by electron beam evaporation method

    , Article Optical and Quantum Electronics ; Volume 53, Issue 8 , 2021 ; 03068919 (ISSN) Shakoury, R ; Talebani, N ; Zelati, A ; Ţălu, Ş ; Arman, A ; Mirzaei, S ; Jafari, A ; Sharif University of Technology
    Springer  2021
    Abstract
    In this study, ZrO2 coatings with different thicknesses were grown by the electron beam evaporation technique. The crystalline structure was studied by XRD analysis which suggested the tetragonal and monoclinic phases for ZrO2 coatings. Additionally, the film thickness slightly enhanced the crystallinity. The surface morphology and fractal features were analyzed using Scanning Electron Microscopy (SEM). The surface statistical parameters and the fractal geometry were employed to analyze the impact of the coating thickness and homogeneity on the morphology of the films. The statistical processing and fractal dimension revealed variations in the morphology parameters due to the electron beam... 

    Effect of annealing on the micromorphology and corrosion properties of Ti/SS thin films

    , Article Superlattices and Microstructures ; Volume 146 , 2020 Rezaee, S ; Arman, A ; Jurečka, S ; Korpi, A. G ; Mwema, F ; Luna, C ; Sobola, D ; Kulesza, S ; Shakoury, R ; Bramowicz, M ; Ahmadpourian, A ; Sharif University of Technology
    Academic Press  2020
    Abstract
    Ti and TiN thin films were deposited by means of electron beam evaporation on stainless steel substrates, and subsequently annealed at different temperatures (650, 750 and 850 °C) in a nitrogen atmosphere. The surface morphology of the films studied by atomic force microscopy (AFM), was found to exhibit specific multifractal properties depending on the annealing temperature. It turned out that the width of the multifractal singularity spectra, f(α), decreased as the annealing temperature increased up to 750 °C, but it increased when the temperature was kept at 750 and 850 °C accompanied by the rapid development of the surface objects. The generalized fractal dimension followed a similar... 

    Optical properties and morphology analysis of hexagonal WO3 thin films obtained by electron beam evaporation

    , Article Journal of Materials Science: Materials in Electronics ; 2020 Shakoury, R ; Arman, A ; Rezaee, S ; Korpi, A. G ; Kulesza, S ; Luna, C ; Bramowicz, M ; Mardani, M ; Sharif University of Technology
    Springer  2020
    Abstract
    WO3 films with thicknesses between 550 and 853 nm were deposited on glass substrates using the electron beam evaporation method at room temperature. The microstructures and surface roughness of the films were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). It was observed that the crystalline structure of the WO3 thin films significantly changes from the amorphous to crystalline states with a crystalline texture, and the mosaicity and grain size dependent on the film thickness. The transmittance spectra of the obtained WO3 films were measured in the range from 340 to 850 nm, and the Swanepoel method was used to determine the refractive indices and the thicknesses of the... 

    Optical properties and morphology analysis of hexagonal WO3 thin films obtained by electron beam evaporation

    , Article Journal of Materials Science: Materials in Electronics ; Volume 32, Issue 1 , 2021 , Pages 798-805 ; 09574522 (ISSN) Shakoury, R ; Arman, A ; Rezaee, S ; Korpi, A. G ; Kulesza, S ; Luna, C ; Bramowicz, M ; Mardani, M ; Sharif University of Technology
    Springer  2021
    Abstract
    WO3 films with thicknesses between 550 and 853 nm were deposited on glass substrates using the electron beam evaporation method at room temperature. The microstructures and surface roughness of the films were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). It was observed that the crystalline structure of the WO3 thin films significantly changes from the amorphous to crystalline states with a crystalline texture, and the mosaicity and grain size dependent on the film thickness. The transmittance spectra of the obtained WO3 films were measured in the range from 340 to 850 nm, and the Swanepoel method was used to determine the refractive indices and the thicknesses of the... 

    Multifractal and optical bandgap characterization of Ta2O5 thin films deposited by electron gun method

    , Article Optical and Quantum Electronics ; Volume 52, Issue 2 , 2020 Shakoury, R ; Rezaee, S ; Mwema, F ; Luna, C ; Ghosh, K ; Jurečka, S ; Ţălu, Ş ; Arman, A ; Grayeli Korpi, A ; Sharif University of Technology
    Springer  2020
    Abstract
    The micromorphology of tantalum pentoxide (Ta2O5) thin films, deposited on glass substrates by electron gun method, has been analyzed using atomic force microscopy (AFM), UV–Vis–NIR spectrophotometry and multifractal analyses. Two samples were grown at basic pressure of 7 × 10−6 mbar, work pressures of 1.3 × 10−4 and 2.0 × 10−4 mbar, and thicknesses of 0.38 μm and 0.39 μm, respectively. Subsequently, these samples were annealed at 300 °C for 2 h. The physical, structural and optical analyses were investigated by spectroscopic ellipsometry, spectrophotometry and AFM. The measured transmittance spectra were studied based on the Swanepoel method, whose results also yielded to the estimation of... 

    Optical properties, microstructure, and multifractal analyses of ZnS thin films obtained by RF magnetron sputtering

    , Article Journal of Materials Science: Materials in Electronics ; Volume 31, Issue 7 , 2020 , Pages 5262-5273 Shakoury, R ; Arman, A ; Ţălu, Ş ; Ghosh, K ; Rezaee, S ; Luna, C ; Mwema, F ; Sherafat, K ; Salehi, M ; Mardani, M ; Sharif University of Technology
    Springer  2020
    Abstract
    The morphology, structure and optical properties of zinc sulfide (ZnS) thin films prepared through radio-frequency (RF) magnetron sputtering have been analyzed using atomic force microscopy (AFM), UV–Vis–NIR spectrophotometry, X-ray diffraction, and multifractal analyses. The X-ray diffraction patterns revealed that all ZnS thin films show a single peak at around 29.6°, which has been ascribed to the (111) planes of sphalerite phase, indicating that the growth direction of the films is the [111] direction. UV–Vis–NIR transmittance spectra were used to determine the refractive index of the samples, their thickness, and their band gap energy, showing the optical and semiconductor properties a... 

    Network vulnerability analysis through vulnerability take-grant model (VTG)

    , Article 7th International Conference on Information and Communications Security, ICICS 2005, Beijing, 10 December 2005 through 13 December 2005 ; Volume 3783 LNCS , 2005 , Pages 256-268 ; 03029743 (ISSN); 3540309349 (ISBN); 9783540309345 (ISBN) Shahriari, H. R ; Sadoddin, R ; Jalili, R ; Zakeri, R ; Omidian, A. R ; Sharif University of Technology
    2005
    Abstract
    Modeling and analysis of information system vulnerabilities helps us to predict possible attacks to networks using the network configuration and vulnerabilities information. As a fact, exploiting most of vulnerabilities result in access rights alteration. In this paper, we propose a new vulnerability analysis method based on the Take-Grant protection model. We extend the initial Take-Grant model to address the notion of vulnerabilities and introduce the vulnerabilities rewriting rules to specify how the protection state of the system can be changed by exploiting vulnerabilities. Our analysis is based on a bounded polynomial algorithm, which generates the closure of the Take-Grant graph... 

    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) Abdolvahab, R. H ; 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) Abdolvahab, R. H ; 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) Abedpour, N ; 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) Abedpour, N ; 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) Molk, A.M.N.G ; 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) Radja, N.H ; 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... 

    Multifunctional hyperelastic structured surface for tunable and switchable transparency

    , Article Applied Sciences (Switzerland) ; Volume 11, Issue 5 , 2021 , Pages 1-11 ; 20763417 (ISSN) Mahabadi, R. K ; Goudarzi, T ; Fleury, R ; Naghdabadi, R ; Sharif University of Technology
    MDPI AG  2021
    Abstract
    We leverage the crucial hyperelastic properties of a multifunctional structured surface to optimize the reconfigurability of the electromagnetic transmission under large nonlinear mechanical deformations. This multiphysics, multifunctional, hyperelastic structured surface (HSS) offers two simultaneous intriguing functionalities; tunability and switchability. It is made of copper reso-nators and a Polydimethylsiloxane (PDMS) substrate, which is one of the most favorable deformable substrates due to its hyperelastic behavior. The proposed HSS is fabricated via an original cost-effective technique and the multiphysics functionalities are captured in both experimental tests and numerical... 

    MaxHiC: A robust background correction model to identify biologically relevant chromatin interactions in Hi-C and capture Hi-C experiments

    , Article PLoS Computational Biology ; Volume 18, Issue 6 , 2022 ; 1553734X (ISSN) Alinejad Rokny, H ; Modegh, R. G ; Rabiee, H. R ; Sarbandi, E. R ; Rezaie, N ; Tam, K. T ; Forrest, A. R. R ; Sharif University of Technology
    Public Library of Science  2022
    Abstract
    Hi-C is a genome-wide chromosome conformation capture technology that detects interactions between pairs of genomic regions and exploits higher order chromatin structures. Conceptually Hi-C data counts interaction frequencies between every position in the genome and every other position. Biologically functional interactions are expected to occur more frequently than transient background and artefactual interactions. To identify biologically relevant interactions, several background models that take biases such as distance, GC content and mappability into account have been proposed. Here we introduce MaxHiC, a background correction tool that deals with these complex biases and robustly... 

    SER of M-PSK modulation in incremental-selective decode-and-forward cooperative communications over Rayleigh fading channels

    , Article International Conference on Advanced Communication Technology, ICACT, 13 February 2011 through 16 February 2011 ; February , 2011 , Pages 432-437 ; 17389445 (ISSN) ; 9788955191554 (ISBN) Renani, R. A ; Saadat, R ; Aref, M. R ; Mirjalily, G ; Sharif University of Technology
    2011
    Abstract
    In this paper we consider a cooperative communication systems over Rayleigh fading channels. The system utilizes a combination of incremental and selective decode-and-forward (ISDF) relaying protocols. The symbol error rate (SER) of M-PSK modulation for the ISDF protocol is derived. Using an approximation of the SER expression, the optimal power allocation is investigated. In order to reduce the complexity of the receiver, we used a modified version of the ISDF protocol which does not use the storage or retransmission of the first phase signal. We also derived optimal power allocation coefficient for modified ISDF. It has been noted that for the optimal power allocation in the ISDF protocol,... 

    Power allocation for incremental-selective decode-and-forward cooperative communications over Rician fading channels

    , Article International Conference on Advanced Communication Technology, ICACT, 13 February 2011 through 16 February 2011 ; February , 2011 , Pages 730-734 ; 17389445 (ISSN) ; 9788955191554 (ISBN) Renani, R. A ; Saadat, R ; Aref, M. R ; Mirjalily, G ; Sharif University of Technology
    2011
    Abstract
    In this paper we consider a relaying communication system over Rician fading channels. In this system we assume simple Incremental-Selective Decode-and-Forward (ISDF) protocol, which is jointly combining incremental and selective DF relaying protocols. In this protocol, storage or retransmission of the first phase signal are not allowed. We analyze the symbol error rate (SER) performance of the recommended protocol with M-PSK modulation. We evaluate the performance of the protocol in the frequency nonselective slow Rician fading channels. Using the approximation of the SER expression, the optimal power allocation is investigated. Our results show that at least 50% of total power must be used... 

    Efficient and practical protocol for silylation of hydroxyl groups using reusable lithium perchlorate dispread in silica gel under neutral condition [electronic resource]

    , Article Journal of Organometallic Chemistry ; 2006, Volume 691, Issue 5, Pages 817–820 Azizi, N. (Najmodin) ; Yousefi, R ; Saidi, M. R ; Sharif University of Technology
    Abstract
    A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups